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+[{"q_id": "5ld1qa", "category": "Repost", "title": "why does stretching feel good?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dbuxo0k", "dbuwmjh", "dbuwokt", "dbvn49y"], "text": ["as u/Midnight Rising said, you use your muscles all day long. however you also use them to an extent at night. they tend to tighten up do to this. most people compare muscles to a rubber band, however when you use a rubber band, you cause it to wear down and break. when you use a muscle it actualy tightens. this is usually do to some chemical you release during activities (someone help me I don't remember the chemical). so basically think of your muscles as a rope. and using them ties knots in said rope. these muscles are connected to different things, so having more rope to spare makes it easier to work with. however, by making these knots, you have \"less\" rope and it makes it harder to move. stretching is like untying those knots. you give out \"more\" rope and make it easier to move or do things. your muscles are more free and less inhibited. it's not so much that stretching feels good as it is that not stretching feels bad. it's just the comparison of before and after that makes you feel better. side note, you should stretch often and thoroughly. tight muscles are a pain in that area, however they can cause more pain after a period of time due to the areas they connect. for example my back hurts a lot due to my posture. but many areas of my back hurt due to the knotted muscles pulling on other objects. and for the love of God if I'm wrong please someone correct me in a nice way so I can do better for myself, and forgive any typos. kinda drunk", "All those little motions you make throughout the day make your muscles tighten up. Stretching helps this, making your muscles go back to normal!", "After long periods of inactivity, your muscles, tendons, legements, etc., are at rest. When you stretch, your body releases these chemicals called marklar that, much like n-dolphins, help you feel better.", "Also, a lot of things that are good for you \"feel good.\" It's like nature's motivation. Eating feels good, which is nature's way of motivating you to take in energy. Having sex feels good, which is nature's way of motivating you to reproduce. I think somewhere along the line in evolution, essential tasks/behaviors became intertwined with the activation of reward centers in your brain. So if in some bizarro universe licking your nipples was essential for your survival, that would feel good too, because everybody who hated licking nipples would've died off."], "text_urls": [[], [], [], []], "score": [52, 8, 7, 3]}}, {"q_id": "5ldkl0", "category": "Repost", "title": "Why blueprints are done on blue paper", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dbux617", "dbv8beh"], "text": ["The drawings (before computers) were done on a special kind of paper that was then put into a tube filled with ammonia gas. The ammonia would react with the paper to generate the blueprint. The special paper used was tinted blue by the chemical which reacted with the ammonia and the lines creating the drawing became dark blue.", "Blueprints are actually [cyanotypes.]( URL_0 ) I work with them regularly at my job at the Historical Society of Pennsylvania. There are two cool things about them. They will fade if let out in natural or artificial light, but will become brighter again when placed in darkness, and, for a time, they were used as a cheaper alternative to other photographic processes, so there is a lot of cool photography in shades of blue. At HSP we have a beautiful cyanotype scrapbook of a 1900s bohemian couple touring Europe on bikes. I know some artists still use the process as an aesthetic choice, also cause you can still make them yourself fairly easily. I know they were replaced by [Photostat copying]( URL_1 ). I don't know that much about the actual chemical process and method of creating them, but I hope that helps."], "text_urls": [[], ["https://en.wikipedia.org/wiki/Cyanotype", "https://en.wikipedia.org/wiki/Photostat_machine"]], "score": [19, 3]}}, {"q_id": "5ldt11", "category": "Repost", "title": "What is the significance of prime numbers in encryption? Why are we trying to find bigger ones?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dbuzva4", "dbuycp6"], "text": ["If you take one number, let's say five, and multiply it by itself some number of times, let's say three, you get an exponential expression, which we would write in this case as 5^3 = 125 which we say as five to the power of three is 125. If we made the three bigger, the result would get huge very fast. It's really easy for a computer to calculate an exponent though. On the other hand, what if we knew that 5 raised to some power is 78125, can we easily figure out what the missing number is? This is still very easy for computers to do using a function called the logarithm. Remember that when you divide two numbers, a/b, you may get a remainder. We call this remainder the modulo of base b (the denominator, or second number in the division). Sometimes it's just called 'the modulo', for short if it's understood what the base is. We will use base five. What is the modulo of 7^2? 7^2 is equal to 49, if we divide by five there is a remainder of 4. So the modulo is 4. This is still a very easy computation for a computer to do. But what if we know that 7 raised to some power modulo 5 is equal to 4; can we figure out what the mising number is? There's a limited number of answers you can get, so you know that there has to be more than one possible solution. It turns out that solving this problem (called the discrete logarithm problem) is very hard for computers to do. Any computer could handle the given problem easily, but only because the numbers used are really small, it becomes essentially impossible for sufficiently large numbers. So what does this have to do with prime numbers? Let's say you have some known number raised to the power of a variable modulo some known base, and you start plugging in values for the variable, 1,2,3 and so on you will eventually get to a point where the sequence of values starts repeating itself. Every number in the sequence will be between zero and one less than the base of the modulo, but you might not get *all* of these. It turns out that if the first constant is a prime number, you will get every possible value no matter what the base is. This is the mathematical property that public key encryption (the kind that relies on prime numbers) exploits. I mentioned before that crypto systems need to use really big prime numbers. A more honest statement, mathematically, would be that they rely on kinda large prime numbers. The size of the prime number depends on how much computing power it needs to be able to withstand. As computers in general get faster, we need to use larger prime numbers to remain secure. The largest prime numbers that we know are much, much, much, much bigger than the prime numbers we deal with in crypto. Knowing these numbers isn't particularly useful in and of itself. Mostly we're just interested in finding *more* prime numbers because there are still lots of things the best mathematicians can't figure out about them. Because there are just so many of them though, we tend to be interested in the biggest ones we can find (we've known for a few thousand years that there is not a biggest prime number). One interesting property of prime numbers is that the bigger you get, the further apart they become. This means that when a new biggest prime number is found, there's a good chance it will be a fair bit larger than the previous one.", "Mainly because we have no good method of prime factorization with computers, and the complexity of the problem scales exponentially in trying to find bigger primes. RSA for example mainly relies on multiplying two relatively large primes together. You could theoretically decrypt it if you could find the prime factorization of the very large number used to encrypt it. But that is task still to complex for the world's best supercomputers. Currently the biggest primes are found via mathematical tricks, such as the famous 2^n - 1, which will for quite a few values of n, spit out a prime number."], "text_urls": [[], []], "score": [8, 3]}}, {"q_id": "5ldw62", "category": "Repost", "title": "How are fireworks able to make certain shapes while exploding in mid air? Such as a smiley face, heart, star, etc.", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dbuz1c6", "dbuyt8x"], "text": ["Because the secondary charge is packed in the shape of a star or a smiley and a small charge ignites and inflates the shape before the secondary charge blows up. URL_0", "That's a good question. I've also wondered about this and other related effects. I'd like to add to this question by asking the following: How do they figure out the angles so that the audience, let's say on a beach, are able to see the shapes as they are intended? Also, are there multiple fireworks needed to make effects...like ink blot art?"], "text_urls": [["http://www.skylighter.com/images/newsletter/116/8-inch-star-pattern.jpg"], []], "score": [14, 5]}}, {"q_id": "5lem9z", "category": "Repost", "title": "What exactly does it mean for a system to be 8 bit/16 bit/32 bit/64 bit? Why is it in multiples of 8?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dbv7k19", "dbv92v2", "dbv3ozc", "dbw1qi9", "dbv3my7"], "text": ["A lot of replies in this thread say that it is because a bit is base two and 8/16/32/64 are powers of 2. This is NOT the correct reasoning. Firstly, each bit is a binary digit that is either 0 or 1 (think of a switch, it's either on or off). Each bit has 2 possibilities. A 1-bit system is obviously not too useful because of the two states it can represent, so we connect multiple 1-bit systems together. So for a 2-bit system, there are 2^2 = 4 representations. 3-bit systems have 2^3 = 8 representations, 2^4 = 16 representations, etc. You might have seen or heard that computers cannot handle numbers larger than about 2.1 billion. This is where the limitation of 32-bit systems come from (2^31 is about 2.1 billion. One of the bits is used to represent the positive/negative sign). There is nothing stopping you from building a 3-bit system, or a 23-bit system, or a 377-bit system (the point is none of these are powers of 2). In fact, this has been done before. There are modern video cards that have 192-bit memory channels which is not a power of 2. I don't know what the real reason is (perhaps someone who works in processor design can better answer this) but I am suspecting that this comes down to convenience and scalability from old to new software/hardware. System with weird bit sizes are usually designed to do a specific task. For example, digital signal processors (DSPs) have used 9 bits, 18 bits, 26 bits, 48 bits, etc. in the past.", "It indicates the size of a pointer(computers use this to address memory). 32 bit pointers can address up to 2^32 bytes(around 4 gigabytes) of memory and 64 bit pointers can address up to 2^64 bytes or 16.8 million terabytes. It is multiple of 8 because for almost all computers, 1 byte is the minimum addressable unit of memory and 1 byte equals 8 bit.", "It's multiples of 2, and it's because bits are 2-base. This means they are either 0 or 1. So when we have a number that is 8-bit it means it is a number represented by 8 bits. This can be converted to the regular number system -- decimal also known as 10 base -- by going from right to left along the 1s and 0s and adding. The bit on the right is 1 or 0. The next bit to the left is 2 or 0. The next bit to the left is 4 or 0. The next is 8 or 0, etc. For example, 0110 in binary is equal to 6, because the 1 spot is 0, the 2 spot is 1, the 4 spot is 1, and the 8 spot is 0. This means we have a 2 and a 4, so we add them to get 6. In this example we are dealing with a 4-bit number, because there are 4 bits. In an OS it generally means the size of an integer, and can affect things like the amount of memory that can be used. Interesting addition: 4 bits is a nibble, 8 bits is a byte.", "Sigh... Computer engineer here, all of the answers in this thread have thus far missed the mark. The simplest and most correct answer is that there is no technical definition of a microprocessor's \"bit width\". They're largely marketing terms that rest on a foundation defined entirely by the manufacturer. Consider for example the MIPS R4000 microprocessor used famously in the Nintendo 64. It's widely known as being one of the first \"64 bit\" microprocessors, and it does indeed have 64-bit instructions. However, most of these 64-bit instructions are implemented in microcode on top of 32-bit harder and involve the sequential execution of multiple 32-bit instructions. Despite its namesake, very few if any Nintendo 64 games used the R4000's 64-bit instructions because they were simply too slow. Consider next the Intel 8086, marketed as a 16-bit microprocessor. It is true that the 8086 has 16-bit general purpose registers and can perform only 16-bit arithmetic, but it uses a segmented address space which provides access to 20 bits worth of memory (1 megabyte). Intel introduced the MMX instruction set extensions with the P5 series of microprocessors. The MMX instructions included the ability to load and store 64-bit values in the MMX registers, perform boolean logic operations on 64-bit values, shift 64-bit values, perform vector arithmetic on packed values (two 32-bit values, four 16-bit values, or eight 8-bit values), but did not include the ability to perform scalar arithmetic on unpacked 64-bit values. Despite having some 64-bit capabilities, they were not marketed as 64-bit microprocessors. The most common reference point for a microprocessor's \"bit width\" is the width of the microprocessor's general purpose registers which is where most of the microprocessor's instructions are executed. Specialised registers such as those used for floating point arithmetic, vector arithmetic, and special functions are not considered, nor is the width of the external address and data busses. The Intel 8088 was an Intel 8086 with an 8-bit external data bus rather than a 16-bit external data bus yet it was still marketed as a 16-bit microprocessor with a 20-bit address space.", "It means how much memory can be addressed. The bigger the number the more memory. Since computer memory must be a power of two the measure is expressed as such."], "text_urls": [[], [], [], [], []], "score": [27, 5, 5, 5, 3]}}, {"q_id": "5lemcr", "category": "Repost", "title": "what is a director/maestro doing with his hands?", "title_urls": {"url": []}, "selftext": "Everybody has his sheet of music, so what is he doing?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dbv4n6k", "dbv4hfd", "dbv5jf7"], "text": ["In the most basic sense... you have a group of 40 people that all need to start playing their instruments at the same second. Without the director, they'd basically never know when to start, or the start of the song would ve extremely choppy as people are trying to catch up or figure out when to start. Unless someone yelled out \"ok start\" and then began playing. The director is that role. And then, the director keeps tempo and signals coming changes in music. Again, if he wasn't there, you wouldn't know how fast or slow to play. You'd need to just hope that someone is staying on beat and that you can follow them. The director centralizes that. He is leading. Not some random person who should be focused on playing their music.", "He is controlling tempo or beats per minute. He can also signal a crescendo, an increase of volume, or a decrescendo, a decrease in volume and how slow they should be. He can signal to slow down or pick up speed. Sometimes, he will help emphasize certain instrument or vocal parts. For example, he may wave his hands in time of a particular instrument's parts. The orchestra knows the music and if needed, they could play the whole piece without the maestro, but it is hard to keep a steady pace. The maestro controls how fast they go and keeps them unified during harder parts, such as a slowing down, picking up, growing louder, or growing softer.", "With the left (usually for right-hand dominant) he keeps time. Upward counts one. Down counts two, left three, right four. The larger the movement, the more volume he wants out of the band/choir. He may supplement with the right if he feels there needs to be emphasis on the degree of change in speed/volume. With the right, he queues in or gestures out the next group or helps adjust speed/volume/execution of the phrase or note."], "text_urls": [[], [], []], "score": [32, 13, 9]}}, {"q_id": "5lenlt", "category": "Repost", "title": "What is the difference between a good lawyer and the \"best lawyers money can get you\" while defending you in a case?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dbv46g3"], "text": ["To put it simply as thus: A good lawyer works within the law to get you the best result possible. They work with the system, and don't break the rules, and so are good all round. The best lawyer money can buy, however, is one who knows when, where, and how the rules can be bent. They know how far the rules can be bent, and which rules can be bent in which situation. And thus, they are able to get a much more favourable outcome that the good lawyer can provide, albeit at a high cost. In addition to this, the best laywers are very specialised in what they do. A top end laywer who defends you in a murder case, for example, may have spent their entire career studying the criminal laws for murder, and cases where the rules have been bent, both successfully and unsuccessfully, and what results came out of it. If you hired this lawyer then, to defend a libel case, or a common dispute, they wouldn't be as good as a different top end laywer who has studied these cases. Think of it like surgeons. Most surgeons are good all round, and they can deal with most types of surgery, with no issues. But for specific and technical surgeries, like organ transplantation, brain surgery, or reconstructive surgery, a regular surgeon is not going to cut it, and you need to hire a specialist to get the job done the best. EDIT: Further clarification."], "text_urls": [[]], "score": [43]}}, {"q_id": "5lephi", "category": "Repost", "title": "why do you have to turn your phones off for takeoff and landing in planes", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dbv44pn", "dbv4b0e"], "text": ["Aircraft Maintenance here. It does not mess with the navigation equipment at all, despite what they tell you. It is mostly to prevent distractions with the crew during crucial periods of flight for individuals who don't have the courtesy to put it on silent.", "Here's the explanation given by one of my electromagnetic fields and waves lecturers: The lead time on producing new aircraft is 10-20 years, while the lead time on new phones is more like 5. This means that the EM interference protections on planes are 15 years out of date - still designed, at best, for very early 4G and 2.5G wifi b/g. The actual reason is more of a precaution than knowledge that any particular issue could occur. Mythbusters tested it and showed that it isn't anything to actually worry about."], "text_urls": [[], []], "score": [14, 8]}}, {"q_id": "5lex5r", "category": "Repost", "title": "why do people cover their mouths/foreheads/faces when they are surprised?", "title_urls": {"url": []}, "selftext": "The kind of action all girls seem to make when they are proposed to, for example.", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dbvgz3e"], "text": ["If this is a repost ( it's flaired as such) can whoever tagged it please link up to the repost? There's currently one comment here (besides mine) and it's been removed."], "text_urls": [[]], "score": [3]}}, {"q_id": "5lfhvy", "category": "Repost", "title": "how come when waking up with a stuffy nose only one nostril is usualy clogged?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dbva7q6"], "text": ["You have something called a nasal cycle, in which one sinus swells slightly, then switching to the other, after a bit of time. Mostly you don't notice it, but when ill and your nose is easier to block, you do notice"], "text_urls": [[]], "score": [14]}}, {"q_id": "5lfkm7", "category": "Repost", "title": "Why are weightlifters fat?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dbvji5u", "dbv9pby", "dbva5de", "dbv9zy7", "dbvgpr7", "dbvik3u", "dbvqx07", "dbvq18b"], "text": ["long-time \"Olympic-Style\" lifter here... (I lift primarily to be strong and stay in shape. I'm not \"competition strong\" nor am I \"super buff\" in the slightest, but I do lift heavy with the goal of increasing strength and muscle.) The way you get stronger and build muscle is by putting on mass. This means you have to eat at a caloric surplus everyday in order to fuel the growth, development, and healing of your muscles. If you do not eat enough, you cannot increase muscularity, and eventually cannot even maintain it. This is because muscles are insanely dense and require more 'food' to sustain. If you don't, and your body starts 'burning' calories, it will burn some readily available fat first, but then eventually begin breaking down excess muscle tissue because it 1) gives more fuel for your body, and 2) is harder to maintain, so it'll burn it off to get you back to an equilibrium based off of what you're eating. Since these competitors are trying to be as strong as possible, they do not balance their surpluses with diets, because dieting will cost them strength and physical muscle in the process. They eat big, lift big, get big. They don't want to lose any muscle. Ever. I can personally say that you will lose noticeable amount of your peak strength if you go on a diet in order to lower body fat and get \"ripped\". For me, I lost roughly 10-15% of my peak lifting after dieting and losing about 30lbs (from 182lbs at 24% BF to 153lbs at 13% BF). 10-15% for me is not much. But if those competitors did that, they would basically lose their ability to compete in Strongman comps. They would probably sacrifice up to a quarter of their lift numbers unless they used steroids in order to counteract the potential loss of muscle.", "1. Not all of them are. 2. Cutting weight reduces strength, which is the entire point of competing in lifting.", "Most aren't, since Olympic weightlifting and powerlifting (I'm assuming you meant one of these) are weight class sports, so to get the most muscle and strength in your weight class you'll need to be low in bodyfat. However, there's usually a superheavy class which is something like 125kg+. For lifters in that category, there's no reason not to get fat (until it limits mobility) since it's much easier to gain muscle and avoid injury while on a calorie surplus.", "As the muscles get larger, a thick layer of subcutaneous fat forms over their [huge] muscles, making them look fat. Without the musculature, they would look like a person of average build. The reason for this is ~~to provide a large supply of ready-to-use energy that the muscle can grab whenever it needs.~~ to protect the muscles from physical damage, and help in hormone production. In addition to this, when they are actively lifting, their stomach pushes out because of the sheer amount of muscle there. Zyndrunas Savickas is a good example of that. He is around 160kg, but is around 18% body fat (average level). EDIT: Further clarification EDIT2: Major correction", "Different weightlifting goals=different body types. Some lift to be strong, some lift to sculpt the body, to highlight the muscles. You will never see a body-builder enter or win a \"Strong Man\" Competition. Totally different animal. Totally different goals. Body builders have to lift heavy weights but they are far from being as strong as someone training for a Strong Man competition. A typical body-builder will for example deadlift 300 to 400 lbs for reps whereas a Strong Man competitor will deadlift nearly double that for reps while training. Eddie Hall has the deadlift record for \"bar and straps only\" at 1025 lbs. Also, Strong Man competitors eat a lot of food, a whole lot of food, to fuel their bodies. Bodybuilders eat a lot as well but not nearly as much as a Strong Man competitor.", "Most weightlifters aren't fat. But basically eating a lot (more calories than you burn) helps you get stronger. A common method is a period of 'bulking', eating a lot to get stronger, and probably gain some fat as a result. Followed by a shorter period of 'cutting', eating fewer calories than you burn in order to lose the gained fat.", "Because you'll never be at your strongest when totally lean, most likely. These guys lift and eat like crazy to ensure their muscles are growing at a maximum, ensuring max strength. This requires a lot of calories, and even if you're eating super clean, you'll gain some fat. Essentially you saturate your body's caloric uptake so that you are your strongest, with some fluff being added as collateral damage.", "It depends on goals and what works best for you. Some bodybuilders bulk up during off-season and then cut for competition while others remain quite lean year-round and that's just figuring out what works best for you. It's easier to just bulk because your diet can be no as strict and you progress faster but you also have to cut more after that. Olympic weightlifting and powerlifting has weight classes so lifters that want to be competitive choose the best class for themselves. If you're taller/have a bigger frame you'd wanna go to a higher weight class so you can fill out your frame because a shorter lifter at the same weight can carry more muscle and outlift you. Like bodybuilders, some weightlifters and powerlifters cut for a competition or do water manipulation or whatever else they do to get in their weight class. Also if you look at lighter classes you can find some really jacked powerlifters or weightlifters. I've noticed that usually lighter lifters deadlift more than they squat and it's the opposite for heavy guys. All that thickness makes it harder to get down in the position for the deadlift but for the squat you start from the top and when you descend areas of your body push against each other and provide some support (same for bench but probably less). So that's something to consider how your weight affects how you lift."], "text_urls": [[], [], [], [], [], [], [], []], "score": [91, 53, 34, 12, 8, 5, 3, 3]}}, {"q_id": "5lfw4b", "category": "Repost", "title": "What is the emotional 'awwww' feeling we get when we see cute things? Why does it happen?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dbvdape", "dbvouwg", "dbvoobs", "dbvj7lp", "dbvtowr", "dbvrspq", "dbvrl0o", "dbvs28d", "dbvopu9", "dbvtv64"], "text": ["This is basically the brain releasing neurotransmitters like oxytocin which is normally only released when we are in love or when we feel safe/protected or are caring for children. Allegedly animals we find cute (cats/dogs) were selected for their \"cuteness\" over centuries but what makes them cute turns out to be the ratio/proportion/distance of their eyes and face face shape, which is nearly that of human children. So, in essence only human children were originally meant to elicit that feeling but we have created/found other things that also stimulate that part of the brain and thus sort of tricks us into finding it attractive/urge to protect it from harm. Baby animals are also like this and there have been citations of adult animals caring for young of other species probably also for similar reasons: their brains are sort of hardwired to instinctively care for \"cute things\" which babies of most species are.", "Can anyone explain why, despite being a human male, I find babies to be annoying and uninteresting but my heart melts like an ice cream in the sun when I see a cute little puppy?", "Michael from Vsauce explains it amazingly in his video - URL_0", "I want to know if this sensation is less prominent in people who have had children of their own. Does the stab of awww wane as we have cute children of our own? Does it come back once the children are grown?", "The important news is that humanity has sunk a lot of resources into giving themselves this response. -Entire species of dogs left effectively helpless, but for their capacity to appeal to human standards for oxytocin release. -Entire subreddits devoted to masturbating this oxytocin release. -Tuning competitive impulses to release *other* neurochemicals whenever we present an \"explanation\" that's really just a cursory view of biological artifacts, rather than any proper effort to deconstruct modern human experiences. The thing that's metaphysically happening is that humans want to connect with everything they can, and there are certain visual cues that make that easier. But we have gifs of buildings falling down, and all it takes is a little face doodle to get us to empathize with them. In the present environment, descriptions of neurotransmitters is just another way to release neurotransmitters, not any proper explanation of a thing.", "I can understand the reason we feel 'awww' for babies etc (instinct to take care of offspring) but why do we think fluffy animals are so cute? Humans aren't fluffy. Is this because we've come to associate them with pets as we grow up, and not so much a hardwired thought?", "First off, babies are annoying. They have to be as they need lots of reliable attention to get the care they need to survive. They tune their crying to match the natural resonant frequency of their parents ear canals. This means they also match random other people's ears too. This makes it very tempting to smash them with a large rock. Their parents won't because they are under the influence of oxytocin, but the other tribe members need the awww instinct to prevent random baby smashings. Baby animals trigger it too, because instincts aren't exactly smart. They only need to work well enough for people to survive.", "Question I have is why do I not feel this way towards anything? I have looked at pictures and videos of babies and animals and felt nothing while people around me did.", "It's a vestigial hunting instinct. Notice that it's almost always accompanied by a desire to squeeze the thing as hard as you can.", "Emotions are like memories from our evolutionary history. They direct our behavior without us learning them first, because they are part our genetic code. We respond to certain queues around youth, like a high eye size to head size ratio with a caring impulse. It helps our species survive by making us more likely to care for our young."], "text_urls": [[], [], ["https://www.youtube.com/watch?v=Z0zConOPZ8Y"], [], [], [], [], [], [], []], "score": [1384, 339, 34, 20, 10, 8, 8, 6, 3, 3]}}, {"q_id": "5lgw8l", "category": "Repost", "title": "How does one \"waste water\" when using it in your home. Doesn't it just get added directly back to the water supply?", "title_urls": {"url": []}, "selftext": "Note: NOT in regards to agriculture or outdoor water usage. I just saw a commercial that said something to the effect of not turning off water while brushing wastes like 4 gallons of water. I don't understand this, because according to my admittedly limited understanding of how our water supply works, the water just goes back into the city water supply after its treated.", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dbvlg25", "dbvkbkh"], "text": ["\"Wasting water\" really means \"wasting energy\". Not every place on the planet has a nearly unlimited water source (like Washington and Idaho). In places like California, New Mexico, or Arizona, where clean water is scarce, using more water than you need to means that they have to ship more water from other areas and spend a great deal of money and energy to ensure everyone has the water they need. In those places that are totally flush with clean water, like the aforementioned pacific northwest USA, you really couldn't waste enough water to even be a bother. In places like those drought areas, wasting water means higher water costs for everyone, and higher costs for the city.", "Treating that water on its way out, treating it and pumping it around into storage tanks as fresh water all take energy and machines to make happen."], "text_urls": [[], []], "score": [80, 7]}}, {"q_id": "5linvd", "category": "Repost", "title": "Can we go below absolute zero? Yes - > how / No - > Why", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dbvzcxq", "dbw16d3", "dbvzzpg"], "text": ["You can't go below absolute zero because that's where there is no energy and you can't have negative energy.", "The colder something is, the harder it is to cool it even more, and the more energy it would take. If you tried to cool anything to or below absolute 0 (0 K), it would take an infinite amount of energy. Therefore, you can not cool something to below 0 K the way you would cool something to 1 K or to any other temperature. However, there are cases where a temperature of below 0 K is obtained when you run the maths, but these are actually hotter than an infinite temperature, and you cannot get to below 0 from 0 K by cooling even more. This is a bit harder to explain simply, but I'll try : imagine a bunch of balls on a hill : all the balls will naturally roll to the bottom of the hill. When they are all at the bottom, everything is at its lowest point in energy and nothing is moving, that is absolute 0. If you give a bit of energy to the balls, they start to move a bit higher up the hill. That's the balls \"heating up\". When you heat the balls up enough that they can get anywhere from the bottom to the top of the hill, and are actually distributed everywhere equally, that's an infinite temperature. If you somehow manage to give even more energy to force the balls to stay closer to the top of the hill than the bottom on average, that's when you get to a negative temperature. Hope that is simple enough for a 5 year old!", "It depends on how you define temperature. For most purposes, we simply define temperature on a macroscopic scale as the amount of heat energy in a system. With this definition, absolute zero is an absolute limit (that you can never actually reach). If you place an object at absolute zero next to an object at any other temperature, heat will always flow to the absolute zero object. However, it is possible to view temperature as involving the statistical likelihood that components of your system occupy different energy states. In this sense, a negative temperature becomes possible by fiddling with the entropy and energy involved in a system. But this isn't a 'negative temperature' that makes sense in the more common definition of the term above. I'm not sure there's any way to explain this second definition at an ELI5 level other than to point out that it exists and will never affect your fashion choices. If you're curious about all the details, I'd recommend /r/askscience."], "text_urls": [[], [], []], "score": [5, 5, 3]}}, {"q_id": "5ljkan", "category": "Repost", "title": "Why do we get brain freeze?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dbw7jhn"], "text": ["There is a big nerve at the roof of our mouth. When this nerve gets exposed to extreme cold it hurts and sends pain signals to our brain. That's why sticking your thumb to the roof of your mouth will get rid of brain freeze."], "text_urls": [[]], "score": [4]}}, {"q_id": "5lnd4v", "category": "Repost", "title": "Why is one currency worth more than another?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dbx0bds"], "text": ["It's all to do with perspective. Let's say you and two other friends want to trade. You've got oranges, one friend has apples and the other has peaches. If you want a peach, you could just trade one orange for it. But what happens if you think your orange is worth more than a single peach? If your friend with apples really wants oranges too, he might be willing to give you multiple apples for a single orange. If there's a higher demand for your oranges, you can sell them for more. This is essentially where the \"worth\" of a currency comes from. Traders take a lot of things into account when buying and selling currency. Things like having a strong economy will increase the value of currency, by driving up demand (lots of people want it). If traders feel the currency is high risk, there will be low demand which means in order to sell it you have to drop the value. The external value of a currency isn't everything though. You can buy about 10 Norwegian Kroner for one Pound Sterling, but things in Norway cost about 10 or 20 times as much."], "text_urls": [[]], "score": [4]}}, {"q_id": "5loclz", "category": "Repost", "title": "The P=NP problem", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dbxaah1"], "text": ["*P* and *NP* are both so-called *complexity classes*. They are basically classes of problems in computer science that can be solved in a certain amount of time (Note: Time here means computational steps, not actual time). Problems in *P* take polynomial time, which means increasing the problem size (for a sorting problem for example the number of keys to be sorted) linearly results in a polynomial increase in computation time. Problems in *NP*, on the other hand, are problems that are guaranteed to take longer than polynomial time. They might take up to exponential time (like the breakpoint construction for buchi automata or the [Travelling Salesman problem]( URL_0 )) in the worst case. The *P=NP* problem is now to either proof or disprove whether all problems that lie in *NP* also lie in *P*. This would mean every problem in *NP* also has an algorithm that finds the solution in polynomial time. That would be a huge step forward for computer science since problems from *NP* are generally orders of magnitude harder to solve for large inputs and take up considerable computation time."], "text_urls": [["https://en.wikipedia.org/wiki/Travelling_salesman_problem"]], "score": [3]}}, {"q_id": "5losix", "category": "Repost", "title": "Why can't people float on water while a 197,362 ton ship can?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dbxal1a"], "text": ["Ships displace more water than they weigh. Ships can do this despite being made of metal and being very large, by virtue of being hollow. Even a very large ship weighs less overall than an equivalent volume of water so they float."], "text_urls": [[]], "score": [5]}}, {"q_id": "5lqy1a", "category": "Repost", "title": "How does CGI cost so much money for TV shows?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dbxsesy", "dbxsc1g"], "text": ["It takes a lot of expert animators working hard to make CGI look good, and then a lot of good hardware to render it. Those people all have salaries. Note that it's a LOT harder and more expensive to incorporate CGI into a live-action show than to just make an entire show out of low-grade CGI. The CGI kids cartoons you see are relatively cheap to make because it's totally fine for things to look like shiny plastic spheres or play-dough blobs, it's fine for them to move in simple ways, and because they only make the characters and most of the environments once,and get to constantly re-use them. Doing CGI for a war sequence in Game of Thrones, where you're inventing totally new things for individual scenes and expecting them to look good incorporated into real-life footage, is a lot harder. A lot of CGI TV cartoons use toys or inanimate objects as main characters because that makes it even cheaper. You don't need to carefully animate good facial movements on talking cars and trains and you don't need Barbie and Ken's skin to look soft and natural. The first big all-CGI movie was Toy Story, and they chose toys for exactly this reason -- it was incredibly demanding to create realistic looking stuff, but if you made the characters toys, the fact that they looked like plastic or wood was actually an advantage!", "When you are good at something never do it for free. And render times are long, you need lots of high qualified people for these nice Hollywood cgi effects. This all adds up"], "text_urls": [[], []], "score": [21, 4]}}, {"q_id": "5lrj4e", "category": "Repost", "title": "How much power does a President have. If Presidents come and go, is there a fundamental long term plan that can't be altered by each new leader?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dbxwsfz"], "text": ["The president is the leader of the executive branch of government. Duties and responsibilities include things like: - Appointing people to serve in the cabinet and other high-level government positions - Establishing and maintaining diplomatic relations with other countries - Deciding if/when to bomb another nation (e.g. in retaliation to an attack) - Providing guidance with respect to how federal laws should be enforced and how to prioritize government resources - Approving or vetoing legislation/bills that are passed by congress - Creating executive orders (basically a temporary law/policy put into place by the president, but which is only enforceable to the extent that the executive branch of government has the constitutional power/authority to institute such a law/policy) There is nothing that a president that can do, by himself, that will be guaranteed to survive his presidency (i.e. continue on to the next presidency). However, laws passed by congress can be difficult to repeal later on and unlike an executive order it cannot simply be undone when the next president gets elected into office. So, the president can encourage lawmakers in congress to pass legislation and, if successful, that legislation will likely remain active for many years or decades after they leave office. However, if the president does not have the support of the majority of senators and representatives, then it becomes very difficult to pass legislation. Edit: as others have pointed out (and I should have mentioned), the constitution provides a long-term framework for how the government should operate and what powers and authority each branch of government has. In that sense, it's a long-term plan that cannot be altered by each new leader."], "text_urls": [[]], "score": [25]}}, {"q_id": "5lrqbl", "category": "Repost", "title": "If atomic interactions mean that objects never truly \"touch\" each other, then why do \"collisions\" produce sound (e.g. clapping)?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dbxx5pf"], "text": ["It depends on what you mean by touch. The atoms get close to each other, interact with each other, there is a mechanical impact, the atoms will not pass each other, etc. So it is all the things we relate to touching. It is these interaction between the atoms that cause vibrations in the materials that creates sound. If you do not consider atoms to be touching each other when you clap your hands together then I wonder what you consider touching. It is unlikely that any particles have any size at all but are defined by their interactions with each other. You have to draw the line between touching and not touching somewhere."], "text_urls": [[]], "score": [9]}}, {"q_id": "5lsfog", "category": "Repost", "title": "When my phone doesn't have signal it says \"emergency calls only.\" How can I still make emergency calls without service?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dby1zm7"], "text": ["Its a legal requirement for all wireless carriers. Even if you do not have a valid contract/service plan with a carrier, they _must_ accept 911 calls from your mobile device. Imagine if you have a pay-as-you-go and you're in an accident and need an ambulance. But wait, your pay-as-you-go account has $0 balance! It would suck if you had to call your carrier, give your credit card number, I'm sorry you didn't press a valid entry, please call back and try again meanwhile IM BLEEDING TO DEATH OMG! other side note of interest - when you call 911 your phone goes into emergency call mode - all apps get dumped, the phone app gets highest cpu priority and regardless of how many bars you may or may not have, transmit power is boosted to 11; meanwhile aggressive power management kicks in to maximize battery life to maintain your emergency call for as long as possible; usually your phone will go to 1-2% then power itself down - in emergency mode your phone will run itself until the battery has 0. Meanwhile on the cell tower side, the system will reserve a channel exclusively for your use, kicking other calls if it has to."], "text_urls": [[]], "score": [4]}}, {"q_id": "5lvavv", "category": "Repost", "title": "If cardio is good for your heart health because it speeds up your heart rate for a period of time, why isn't cocaine also good for your cardiovasciular health?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dbyr22q"], "text": ["When you work out, an elevated heart rate is part of a much bigger metabolic system based on needing to send oxygen to places your body normally wouldn't normally require it or as much of it. Your blood vessels will relax among other things and your body will work together in unison. When you do uppers, increased heart rate is simply a by product of the drug where your heart is off doing it's own thing regardless of how else the rest of your body is acting. This conflict is what prevents it from being a good thing since your blood vessels will actually contract, one of the main things that make it a health risk."], "text_urls": [[]], "score": [4]}}, {"q_id": "5lvokp", "category": "Repost", "title": "Why do you see weird shapes like tv static when you close your eyes and press on them?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dbyub7h", "dbyvwus", "dbz3rui"], "text": ["You are stimulating your retina from the outside. You'll notice if you press on the bottom-outside of your eye you see a spot in the top-inside of your vision since that part of your retina receives the light from the top-inside of your visual field.", "Light hits the retina, which sends signals to the brain for interpretation. The random stimulation that is caused by squishing your eye is just that: random. However, your brain still wants to make sense of it, so the randomness is interpreted into something you already know, like TV static, or lights flashing, or colorful geometric shape patterns.", "The phenomenon is called \"phosphenes\" and the cause is still unknown when this occurs without applying pressure to your eye. When you rub your eyes you see light because the photoreceptors ( light receptors or the thing that recognizes light in your eye) are modified mechanoreceptors (receptors that perceive pressure or touch). That means when you push on your eye you can make this receptor think it's seeing light by applying pressure."], "text_urls": [[], [], []], "score": [25, 11, 11]}}, {"q_id": "5lymsb", "category": "Repost", "title": "Why are there so many screw drive types (phillips, hex, etc)?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dbzfcu6", "dbzguw1"], "text": ["Originally the companies had different types so that you would have to buy their size and shape tool for a premium. Not prevalent anymore, but it's a practical thing. i.e hex keys are simple and cheap yet effective, so that's why they are in flat packs.", "Slotted heads were first because of simplicity and cost. The biggest downside is they cannot be torqued very high and are prone to stripping. So other head designs were made to increase the amount of torque and to prevent stripping. The next evolution came in making them tamper proof. Think about the ones you see in bathroom stalls. The other step in creating different heads was for proprietary/monetary reason. If you are a car manufacturer and can make a special bolt that needs special tools to work on then people have to use your dealerships for service. This also applied to the tool manufacturers who would gladly try to engineer a new design as it meant they would be the only company you could buy the tools from needed to work on that component."], "text_urls": [[], []], "score": [5, 3]}}, {"q_id": "5lz4kl", "category": "Repost", "title": "Why do American corporations have the same constitutional rights as citizens? Isn't this the reason they are able to become so corrupt and able to get all their power and control?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dbzix17", "dbziofc"], "text": ["First, as pointed out below, corporations do not have the same rights as people, but they do have a certain legal personhood, which includes some rights. Why? Well, it's sort of the point of a corporation. The while idea, since they first came into existence, was that the corporation existed as a distinct legal entity from the people that owned or ran it. And, in some ways, it's a benefit in the legal field. That a corporation is a person means it can be sued, that it can own and have responsibility for property, that it can be taxed, etc... The controversies have less to do with the idea of corporations bring people than with the extention of particular legal rights to corporations, like free speech rights or religious rights, where there's less clearly a historical basis.", "> The basis for allowing corporations to assert protection under the U.S. Constitution is that they are organizations of people, and the people should not be deprived of their constitutional rights when they act collectively. In this view, treating corporations as \"persons\" is a convenient legal fiction which allows corporations to sue and to be sued, provides a single entity for easier taxation and regulation, simplifies complex transactions that would otherwise involve, in the case of large corporations, thousands of people, and protects the individual rights of the shareholders as well as the right of association. Source: Wikipedia From the same source, it is clear corporations do **NOT** get all the same Constitutional rights as individuals (such as the 5th Amendment)."], "text_urls": [[], []], "score": [12, 3]}}, {"q_id": "5lzfp8", "category": "Repost", "title": "What is Common Core and why do some people hate it so much?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dbzl7ri"], "text": ["Common Core was an agreement between state departments of education on a common set of standards for primary school education. It defines what will be taught, at the concept level. There are two kinds of people that don't like it: A) Anti-Federalists - These people think that schooling is a local matter because it's paid for with local taxes (usually property taxes). They think that local school boards should be making these curriculum decisions and the more that distant government entitles (particularly at the federal level) are involved, the less it will match local needs. B) Traditionalists - These people want to be able to help their kids learn, and they think this would be a lot easier if their kids were taught the same way they were. This is particularly a concern with primary math (addition, subtraction, multiplication, division). Older people learned these math topics through memorization, like flash cards. In the intervening years, educational psychology experiments have discovered that this is not the best way to teach math because it does not scale to algebra. Thus the Common Core (informed by these studies) defined that math would be taught in a more abstract way. This makes many parents \"knowledge of how to learn math\" obsolete, even though math answers have not changed. These two groups can sometimes be allies, for example when the Common Core teaches evolution as science and local school boards would like to teach that there are many possible explanations for animal diversity - including a religiously founded one."], "text_urls": [[]], "score": [3]}}, {"q_id": "5m2uv9", "category": "Repost", "title": "Why do we get \"goose bumps\"? What actually are they?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dc0dv0y", "dc0dbfa"], "text": ["I was always told it also ties to your fight or flight reflex. Same reason why dogs hair will stand up when they are threatened. Heat and cold tied into the body being threatened in an evolutionary type of way", "We get goosebumps usually because we're cold. They are from when we were covered in hair. It raise the hair trapping in the warm air/heat. Ever wonder why a cat or dog is fluffier after being out in the cold. It's because they have goosebumps to keep the heat in."], "text_urls": [[], []], "score": [4, 4]}}, {"q_id": "5m3c0d", "category": "Repost", "title": "Why does cold water from the sink feel warm if my hands are freezing cold from snow?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dc0hcxb"], "text": ["It's all because you are incapable of feeling temperature. You can only feel a change in temperature. Heat always flows from warmer things to colder things. If something feels hot, it's because you are getting heat from it. If something feels cold, its because you are loosing heat to it. If the skin of your hands is colder than the water, the water will feel warm, because you are receiving heat from it."], "text_urls": [[]], "score": [3]}}, {"q_id": "5m60xt", "category": "Repost", "title": "Why does moving forward or backward on a bike make it easier to balance?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dc135rz"], "text": ["When the bike is moving, turning the handlebars causes the front wheel to move sideways, which gives you a way to correct a fall. When the bike is stationary, that doesn't work any more."], "text_urls": [[]], "score": [5]}}, {"q_id": "5m6k0z", "category": "Repost", "title": "How does national debt works?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dc15alp"], "text": ["> How does national debt works? A country (in the form of its Finance Ministry/Treasury) will issue bonds and sell them on the open market. These bonds are obligations by the country to pay back the purchase price, plus interest, after a set number of years. Then after that time has passed, the holder will come to the Finance Ministry, hand in their bond, and get cash back. > And is it possible for a country to pay all of the debt back? Absolutely. It could cover all the outstanding bonds in the regular way and just not issue any new ones, or it could buy all of its bonds back early and cancel them. > And what are the usual interest rates? Depends very much on the country. From fractions of a percent to maybe up to 5% or more for very risky countries like Greece at the height of the Euro crisis. Very respected economies can even issue negative-yield bonds, like Germany did at some recent point I think - when the bond is handed back in, the holder gets less than the bond's original sales price. This is because people trust the German government more than they trust a bank where they would normally deposit their money. > And why do countries take up soo much debt? Sometimes for political reasons (they need to pay for something that they promised their voters). But in general, as long as the interest rate is lower than your economic growth rate, it makes sense to borrow money for investing in things like infrastructure that bring long-term economic benefit. Say a country borrows a hundred million euros today to build a new power station. It's a stable, rich country, so the bond yield (total interest rate) over ten years is 1%. In ten years it will have to pay out a hundred and one million euros, but its tax revenue over those ten years has increased more than 1% - as a share of its budget, 101 million euros today is less than 100 million euros ten years ago. Plus the power station has been powering new homes and factories all this time, which is a great benefit! Generally, if your bond yields are lower than your economic growth, then you can just keep rolling the debt over - borrowing money again to pay off the recently expired bonds. That's how countries maintain debts for very long periods. Because of the economic growth, the burden of the debt actually decreases over time, and it's worth keeping it rolled over. **This, incidentally, is why the enormous US national debt is not too scary.**"], "text_urls": [[]], "score": [17]}}, {"q_id": "5mbj4a", "category": "Repost", "title": "Why do lights that are far away have a \"twinkling\" quality to them?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dc2bm42"], "text": ["Yes, heat & particulate (ice, dust) distortion in the air. That's why cold air provides clearer views, especially for astronomy."], "text_urls": [[]], "score": [6]}}, {"q_id": "5mcc0v", "category": "Repost", "title": "Why does pornography become unappealing, sometimes even gross, after you have finished \"using\" it?", "title_urls": {"url": []}, "selftext": "I have never understood why seemingly the most attractive woman in the world very quickly turns into someone I wouldn't look twice at walking down the street.", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dc2oho6", "dc2y5jr", "dc2nqeq", "dc2iupr", "dc2uut0", "dc2usrp", "dc3e7dq", "dc350fa"], "text": ["I read from somewhere else that when we are aroused, it overrides the disgust. But it is over-simplified. Edit: spelling", "I don't have the sources at hand but here's the gist of it: 1. When you're horny you override some feelings of disgust in your partner. This is to better facilitate passing on your genes. 2. When you \"finish,\" you don't want to keep pumping because your penis acts as plunger and pushes everything out. It's designed that way to push out other's semen but not your own. That's why your body gets hit with chemicals to instantly shut the thrusting down. This is where the disgust comes back, it's part and parcel with the chemical dump and the initial disgust if there was any.", "When u bust a nut, you're experiencing a quick high due to dopamine being released. It goes away after a few seconds and you have a hard come down, just like coming off cocaine. The come down makes you feel depressed and down and that comes with feelings of regret (subconscious) so you look at it and it's not appealing anymore. We like busting nuts not only because it feels good to our schlongs, but it gets us a little high for 2 or 3 seconds.. that's the chase and the come down off that drug is looking at the big bootied chick on your screen with a scowl instead of fervishly choking your chicken to her voluptuous body a few seconds ago", "Because porn is Like eating fast food , you have a craving for it but once you got what you wanted , it is less appealing . Why? Because you don't need it anymore . In the mind the objectif was \" i need something that feel extremely great , a peak of fun !\" After that the mind is satisfied \"task completed\" . Now you are there thinking \" what was i thinking ?!?\" And the cycle continue!", "I mean, it is kinda gross, in every way except people having sexy sex. From a film-making perspective there's usually not a lot to recommend porn - crappy sets, bad acting, kinda unappealing people. When you're horny, hey, all cool because sexy stuff is happening. Once you're done, you're just watching a bad movie with way too many tasteless sex scenes.", "Sex seems mean, selfish, and unsanitary when you remove the context of sex drive and horniness. While horny, everything gross seems hot and kinky. Then you cum and realize you probably did some regretful shit.", "Culture plays a part here too: promiscuity and desire have been deemed suspect when attached to certain genders or situations. Pornography is not ethically neutral. We aren't just talking about the mechanics of sex. We're also talking about the vehicle used to deliver the payload.", "My understanding is that when sexually aroused the human brain inhibits disgust. Disgust is a very useful emotion to make us avoid moldy bread, parasites, contagious diseases and so forth. But if we were disgusted with our own reproductive activities all the time, the species would not have lived on."], "text_urls": [[], [], [], [], [], [], [], []], "score": [51, 40, 19, 11, 7, 4, 3, 3]}}, {"q_id": "5mcd6z", "category": "Repost", "title": "How is soap still a \"cleaning\" product after touching many dirty things?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dc2hrkl", "dc2hs05", "dc2iwx7"], "text": ["Okay so some of the dirt and grime on your hands etc will dissolve in water (like sweat and salt), and some may be washed of just from the force of the water (like actual soil). However some stuff like bacteria can stick to your hands, and things like oil won't dissolve in water. Soap contains a \"surfactant\". What a surfactant molecule has, is one end that \"likes\" water (hydrophilic end) and this will dissolve in water; and another end that \"hates\" water (it likes oil instead, this is hydrophobic). The surfactant molecules can stick to your oil dirt, and help to take them into the water by forming layers around them. They can arrange themselves so that there is a shell of the molecules where on the inside it's all \"water hate\" and the outside is all \"water love\". These layers can form bubble like structures called \"micelles\".", "Soap \"dissolves\" into water and then creates little \"bubbles\" around the dirt/grease and is then left behind in the water as you remove your hands.", "Well your question is asking several things. As you wash your butt with your raw bar of soap (I know you don't use a wash cloth you animal) the outer layers of soap disolve into the water and fats that are on your skin, and the water rinses it off. Each time you use your bar, layers come off of it. It may seem like a lie since hairs stick to it - but it happens. The rate of stuff deposited on your bar is less than what is rinsed off - generally. Also, your bar of soap is a great emulsifier. This means that it disolves organic solvents (fat, oil, petrol) as well as polar solvents (water, some alcohols etc). One side of each soap molecule likes fat, and the other likes water. In chemistry there is a phrase \"like likes like\" meaning that similar molecules will dissolve in similar molecules. Soap just happens to have ends that act like each of the extremes of chemical solutions, so its all good. Soap is made by reacting a strong base (OH-) with fat molecules. Its a relatively easy process developed by pioneers and their ancestors long ago. In short: lye + fat + perfume + mixing = soap. This means as you wet your body and the soap, the soap molecules have a chance to strip away all the fat and organic material from your skin, as well as become absorbed into the rushing rinsing water. Your skin is resilient and alive and connected to each other so it doesn't get taken away (although given a high concentration it would definitely dissolve too) but all the crud on top of you does. In our world, most things are separated into polar and non-polar molecules, and soap dissolves them both. Rinse off the dissolved solution of soap+crud and you have \"clean\" skin. Cleaning your skin with soap also kills beneficial bacteria. Tis a symptom of \"cleanliness\" I suppose."], "text_urls": [[], [], []], "score": [7, 3, 3]}}, {"q_id": "5mcslm", "category": "Repost", "title": "As short-sighted person, when looking at a mirror without my glasses, why do things in the background appear blurry even though I'm standing at a distance where I could normally see things clearly?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dc2keuw", "dc2l4r1"], "text": ["Great observation! (No pun intended) Because a mirror doesn't give you a view of what it 'sees' but merely extends what's called the 'light field' by the same distance that you are away from the mirror. Therefore to be in focus for you an object must be a distance from the mirror whose distance, when added to YOUR distance from the mirror, equals your focal distance.", "Mirror doesn't hold a picture of anything. It merely bends and, well, mirrors rays of light. Shortsightedness is inability to focus rays of light that come from far away into separate points within retina. Retina being the back of your eye where picture is formed. As far as mirror image is concerned, light rays essentially behave the same as looking at an object that's behind the mirror, at equal distance. You can contrast mirror image with something like computer screen. Computer screen holds a picture of whatever its showing you. I once forgot my glasses for a lecture, and used camera of my phone to see the writing on the blackboard. Fun times."], "text_urls": [[], []], "score": [11, 8]}}, {"q_id": "5mcwq4", "category": "Repost", "title": "What is net neutrality?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dc2lb2e"], "text": ["It's the concept that your internet provider is not allowed to discriminate between websites. If you try to visit Netflix, they should treat your network traffic the same way they'd treat it if you want to visit Google or Reddit. In other words, they are not allowed to, for example, have a policy that \"when you visit Netflix, we'll slow down your connection, because we have an in-house video streaming service that we want you to use instead\". Under net neutrality rules, they are required to treat all of your traffic as equal. The reason this is a big deal is that: - it prevents the ISP from upselling you different plans (you're currently on the Google plan. We can see you'd like to stream music from Spotify as well. Would you like to be upgraded to our Streaming+ service? It'll only be an additional $20/month\". - it helps competition. If ISP's were allowed to discriminate against specific sites, then they could, for example, run their own streaming service, and then slow down your bandwidth when visiting competing services and suddenly Netflix would be in trouble. Or Microsoft could enter a partnership with your ISP whereby your ISP would give Bing priority over Google's search engine. Any time you try to use Google, they could slow it down a bit, and when you use Bing they might give that traffic priority. Something like that could easily be used by big sites to prevent competition. Say you wanted to start up a new social network to be the new Facebook. Unfortunately, Facebook has *a lot* of money, and they might just go out to the big ISP's and say \"here's a bag of money. Please give our site priority over this new upstart\". Users then get a worse experience visiting your new site, so they stop using it."], "text_urls": [[]], "score": [4]}}, {"q_id": "5mdzm5", "category": "Repost", "title": "The Lehman Brothers Collapse/ Subprime Mortgage Crisis", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dc2t3dk"], "text": ["A Mortgage: Somebody borrows money in order to buy a house. The taker of the loan now has a house. The owner of the loan now has steady rate of income from this loan until it is paid off. A subprime mortgage: A person with a low income who can't afford a house takes out a mortgage. This is a high risk for the lender, who therefore requires a higher interest or some other compensation. Asset swap: An investor buys a rate of capital from another investor. E.g. Investor A gives investor B $5mill for loans that will pay back $10mill over 10 years. Investor B gets money now. Investor A has more money later. Asset bubble in Lehman Brothers: Somebody goes out and buys an awful lot of loans for real money. Then claim they are really rich. Bubble bursts: Suddenly everyone realises that these loans are not going to be paid back. Suddenly these loans are now declared worthless. Lehman Brothers now has no money, all they have are worthless loans. Scandal: Banks like Goldman Sachs have been instructing their own customers to buy the loans from them that Goldman Sachs themselves have been buying. Thus Goldman Sachs made a fortune. Their customers lost a bundle. Consequences: Poor people lost their houses. Mid range investors lost money. Goldman Sachs got even richer."], "text_urls": [[]], "score": [5]}}, {"q_id": "5me57w", "category": "Repost", "title": "Doesn't Guaranteed Basic Income just cause crazy inflation? Is there any evidence that GBI actually works in the long term?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dc2tus4"], "text": ["Why would it result in inflation? Inflation would only occur if you increased the total money supply too rapidly compared to the total value of goods and services available in the country. If you just redistribute some of it (presumably you transfer the money from other government programs) then there shouldn't be inflation. The two main causes of inflation aside from printing new money are from increased demand outpacing production or from increased costs of production. I don't think providing people a GBI would cause such an increased demand for goods and services that the demand would outpace production. At least I've never seen any studies or numbers that indicate that. There's also no reason GBI would increase production costs. Increasing minimum wage might, but that's because the wages are paid out by businesses. Edit: Of course it depends on the amount, but I'm assuming something reasonable like $5k - $20k. If you give such a high GBI that people quit their jobs en masse or the government has to print money or cancel important programs to pay for it you'll have inflation and other issues. It should also be noted that Alaska already has a GBI of $2000/year, but there are quite a few things different about Alaska from most places like it's small population, climate, and location."], "text_urls": [[]], "score": [8]}}, {"q_id": "5mek5w", "category": "Repost", "title": "Why do humans forget most or everything that happened before 5th or 6th birthday?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dc2y40y"], "text": ["The best theory I've heard so far is that it's based around language development. Until a person has the words and cognitive concept, it's impossible to remember. Some things like walking, eating, sleeping, etc are so innate that we don't need words to learn them. Other things like 'friends', 'birthday cake', 'presents', 'birthday' are more complex. A person doesn't remember something because they don't know that it's something to remember."], "text_urls": [[]], "score": [4]}}, {"q_id": "5mext2", "category": "Repost", "title": "Why do we count seconds, hours, days, and weeks in weird terms like 60, 24, 7 and 52 but once we get to years we go into base ten (decades, centuries, etc.)?", "title_urls": {"url": []}, "selftext": "Seems odd. Never thought about it until now. Edit: Thanks for all the input! Had no idea our system for timekeeping had so much history from so many cultures behind it.", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dc31ezs", "dc3jog6", "dc31c54", "dc3h1d3", "dc30p5h", "dc3u0jh", "dc421oh", "dc3fadg", "dc3fe4g", "dc31nzz", "dc3l3ea"], "text": ["Putting 24 hours in a day came from the ancient Egyptians who split the day into 2 parts. Daytime was 10 hours with an hour of twilight on either side and nighttime was 12 hours. Nighttime was 12 hours based on 36 stars called \"decans\" that the Egyptians used to keep track of time based on when they rose in the sky. 18 decans would be visible at any given time of the year, but 3 were assigned to each side of twilight, so there 12 leftover for nighttime hours. The 60 minutes in an hour and 60 seconds in a minute comes from the ancient Babylonians who liked to split things in base 60. They had a thing for the number 360 because they thought that's how many days there were in year. They also like 60 because, like 12, it can easily be divided into several other whole numbers (2, 3, 4, 6). The 7-day week came up independently in a few ancient societies. It's unclear why exactly, but most likely because it's 1/4 of the lunar cycle. It just so happens that about 52 weeks fit in a year. People didn't start keeping track of years in their current form until significantly later on. The first person to start counting years from Jesus' birth was a Scythian monk named Dionysius Exiguus in 525 CE (and his system didn't become widespread until sometime later). Before that most people would count the number of years of the current king or other relevant ruler. So it would be something like the 10th year in the reign of King Virgo911. In Rome they would also sometimes count the number of years from the founding of the city. Most cultures around the world did this (counting years from a significant event or based on the ascension of a ruler or dynasty) and, in fact, that's what the current calendar does (counts years from a significant event, i.e. the birth of Jesus). We do it in base 10 because we're simply counting years from a reference point. Edit: Since this is picking up some steam, more fun facts. The Romans used an 8 day week during the Republic. They switched over to a 7 day week during the Empire (and officially adopted it in 321 CE). The Mayans had two different length weeks. One of 13 days where the days were just numbered and one of 20 days where the days were named. I'm not really sure how that works in practice. The Jews had a 7 day week because of the creation story taking place over 7 days. It's unclear where 7 came from. The French tried to implement decimal time shortly after the French Revolution, but it never caught on. In decimal time there are 10 hours in a day, 100 minutes in an hour, and 100 seconds in a minute.", "I just want to emphasize that some of these divisions are physical; that is, that's just how they are. The length of the day is fixed -- it's how long it takes for the Sun to move *all* the way around the Earth. At noon on day 1, the Sun is at its highest point. At noon on day 2, the Sun is again at its highest point. The length of the day is the time between these two. How we measure it is another matter. Notice that I didn't say that it's the time that it takes for the Earth to spin around its axis. That's because it actually takes less than a day to do that. It's just that, by the time it has spun around, it's also moved a bit in its orbit, so the point that was directly facing the Sun is now a little bit behind. Also, since the Earth's orbit is elliptical, the length of the day we use is really more of an average. The other physical quantity we use today is the solar year. That's how long it takes for the Earth to go all the way around the Sun. The year is actually *not* exactly 365 days but a bit longer, which is why we add a day every four years or so (the rule for leap years is that we add one day whenever the year is a multiple of 4, unless it's a multiple of 100, in which case we add it only if it's a multiple of 400). Nobody thought, hm, let's make the year 365 days. 365 (and a bit) is just how long it takes for the Earth to go around the Sun. The 7-day week is just something that stuck with us from ancient cultures. The ancient Israelites, for example, used a 7-day week, in which the 7th day was the day of rest. In the Abrahamic traditions, that 7-day week was kept, though Christians and Muslims both changed the position of the day of rest within that week. Other cultures had different weeks. The Mayans, for example, had a 13-day week and a 20-day month, making a 260-day ritual year (that obviously didn't line up with the solar year; they used a different system for that). It just so happened that the 7-day week is the one we use today, thanks in large part to the spread of Christianity, and the fact that there are 52 weeks in a year (plus a day, or two in leap years) is just coincidental. Another physical quantity we use, but a lot less often, is the lunar month. This is how long it takes for the Moon to make its way around the Earth, kinda. Just like with the length of the day, the actual measure is how long it takes between new moon and new moon, when the relative position of the Sun, Earth, and Moon are the same. This is some quantity between 29 and 30 days. Many cultures use it, including the Jews, the Muslims, and the Chinese; the phases of the moon are a fairly reliable way to mark time. Have you ever seen those moon calendars that tell you the phase of the moon on a given day? These are completely unnecessary in lunar calendars -- you always know the phase of the moon because it's the same every month! (The word \"month\" is even derived from \"Moon\" in English!) At some point, the Christians moved to a solar calendar, and they got rid of the lunar months. The thing we call a month now is kind of arbitrary. The fact is that there are a few days less than 12 turns of the Moon around the Earth in one turn of the Earth around the Sun, so they split the solar year into 12 non-lunar months like we have today, each one with 30 or 31 days (I don't know why they made February have fewer), and they no longer line up with the Moon. But the cultures that still use the lunar calendar have to work out ways to deal with the difference. The Muslims simply don't. Their year doesn't line up with the solar year at all and they're OK with that. The Jews, on the other hand, insert a leap *month* 7 years out of every 19, and there are a few other months that get an added day in some cases, mostly in order to make various holidays not fall on various days of the week (the 21st day of the 7th month, Hoshana Rabah, isn't allowed to fall on Saturday, for example). The main impetus here is to make sure that the 1st (Biblical) month is actually in the spring (note that long, long ago, Jews switched to a calendar that begins on the 7th month, which begins in the fall), so a month is added if the 12th month ends too early. In addition to this, I should mention that the division sexagesimal (meaning 60) division of minutes and seconds isn't *actually* from the Babylonians. Before decimals were invented by [John Napier]( URL_0 ) in the late 1500's/early 1600's, people actually measured everything in fractions of 60. This included degrees of a circle and parts of the hour. So a time might be 4 hours and a bit. How much was a bit? 26 60ths and a bit. The first 60th subdivision was tiny so it was called a minute subdivision, and the second subdivision was called... well, they ran out of fucks to give so it was just the second subdivision. So the time could be 4 hours, 26 minute subdivisions of an hour, and 5 second subdivisions of an hour. Of course, you could also have third subdivisions of things and fourth subdivisions and so on, but there wasn't much reason to use them once decimals caught on. On the other hand, hours kept their subdivisions because they were in common use by regular people, and degrees kept theirs because they were used in navigational star charts and such. The only number I haven't explained here is the 24 hours in a day, but I think other people already have so I'll leave it at that!", "364/5 is defined by orbital mechanics. The rest is courtesy of the Sumerian-Babylonian astronomers and mathematicians. Their commoners had rituals centered around the 7-day week but at the same time the mathematicians used a base-twelve arithmetic, creating favour for 5*12=60 minutes per hour. Whereas the roots for \"decade\", \"century\" and \"millennium\" all come from Latin, and Romans used baseless mathematics but favoured multiples of ten. \"Century\" for them basically meant \"a hundred dudes\", such as a unit of hundred Legionnaires led by a Centurion.", "Another fun, somewhat related fact for you. I was told that if you take a look at deck of cards, then that represents a year as well. 4 suites - 4 seasons 52 cards - 52 weeks.", "24 and 60 are more easily divided into smaller amounts. With 10, you can divide by 5 and 2 but that's it. We don't count anything by 52. It's just approx. How many weeks are in a year.", "Somewhat random comment: The calendar should be 13 months of 28 days each (364 days). Leap year should simply add a free day between December and January that isn't in a month. Just a free day for everyone. But no, 31, 28/9, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 is way easier and much more logical.", "A lot of people have great historical information, but are missing why some of these cultures used non-base 10 systems. \"They liked a different base\" is insufficient. 24 and 60 are both [highly composite numbers]( URL_0 ) which is a number that has more divisors than any other number smaller than it. 24, for example, has 8 divisors (1, 2, 3, 4, 6, 8, 12, 24), more than any lower number, such as 20, which only has 6 divisors (1, 2, 4, 5, 10, 20). The advantage of HCM's is their usability is better for general use due to their divisibility. You can divide an hour in half, or quarters, or fifths... in fact, you can divide it into up equal parts 12 different ways (1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30, 60). The Imperial Number system also uses a large amount of HCM's. Using the Imperial System to build a shelf with equal sections is much easier than building a shelf in the metric system with equal sections. Some one once challenged me on this by trying to go to base 10 \"What if the shelf is 10 feet, that doesn't divide evenly into 3 parts!\"... it does, 120 inches is a HCM!", "Solid top explanation. Sixty is divisible by 2, 4, 5, 6, 10, 12, 15, 20 and 30. You divide an hour into 60 smaller, more 'minute' equal time periods (minutes), and then do it a second time into 60 (seconds).", "The Babylonians used a base 60 system, so to them that was a very natural number, like 10 to us. Once you define a week as having 7 days, which has been considered a special number for a very long time, 52 is just how many weeks are in a solar year, so that number isn't really an invention.", "Days to years is pretty obvious. Days to weeks, and weeks to years makes sense because it's an easy to subdivide portions of the year so that they divide nicely with both the solar (year) and lunar (monthly) calendars. Seconds, minutes, and hours are all a function of Babylonian and Sumerian timekeepers, who liked base 12 and base 60 number systems. For whatever reason, we never really tried to move on from that until the French revolution, when Metrification started, and when they tried to include a concept of metric time. It failed miserably, although the rest of the unit system *did* end up working.", "Technically, the Second isn't even based on astronomical observations and movements anymore. Officially, the SI second is now 9,192,631,770 transitions of a cesium atom, which pretty closely approximates 1/31.5M of the time between vernal points ^(known on Earth as the First Point of Aries.... which is actually in Pisces currently). Additionally, the current time of day (TAI) is measured by the number of those seconds or fractions thereof, averaged across ~400 atomic clocks, since some semi-arbitrary point in time that we call January 1st, 1977. We apply a number of leap seconds to that (currently 37) to get UTC time, then we can apply a time-zone correction, and that's how we know the time and date today, technically speaking. While seemingly pedantic, this method actually is critically important to a variety of things. For instance, computers and machinery use it to coordinate events and in some cases motion control across systems. In radio communications, it can be used to synchronize the transmissions of multiple transmitters to allow for proper operation (both cell phones and LMRs make use of this in some situations). Typically it's either determined through a GPS receiver, a local high precision clock, NTP, or PTP, or a combination of those."], "text_urls": [[], ["http://www-groups.dcs.st-and.ac.uk/~history/Biographies/Napier.html"], [], [], [], [], ["https://en.wikipedia.org/wiki/Highly_composite_number"], [], [], [], []], "score": [2355, 67, 33, 29, 25, 19, 6, 5, 3, 3, 3]}}, {"q_id": "5miliq", "category": "Repost", "title": "How does RAM on computers work", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dc3wsw5", "dc3vybr", "dc44qmo"], "text": ["It likely uses the same 4GB over and over. The 'random' in its name means that it supports 'random access' as opposed to 'sequential access'. Random access really means something like 'arbitrary access': you can access individual bytes of RAM quickly even if they're stored far apart, as opposed to a spinning hard disk, which can read bytes stored together closely very fast, but takes a longer time to access a byte that's further a away. edit: A good analogy is kind of like having papers around on your desk as opposed to filed away in drawers. If you need something on your desk, you can kind of just go straight to it. But if it's filed away, you need to take out the file and go through it until you find the paper you were looking for.", "RAM (random access memory) is so named because it is (nearly) just as fast to access one chip as another. As such, as far as I'm aware at least, no OS will prioritize any specific memory locations- an application asks for a block of memory, and the OS reserves whatever it stumbles across that is free first.", "RAM stands for Random Access Memory, meaning that any individual chunk in memory could be accessed at any time. So that 4 GB could be located within those 16 GB, and it doesn't have to be in a continuous chunk. However, since RAM Chips are slower (but much much cheaper) then the memory caches and registers built directly into your CPU, larger continuous chunks of memory are copied into caches, then smaller chunks are copied into registers. After a certain amount of time, the modified chunks of data are copied back into the caches then back into RAM. This process is fairly slow, and if the computer needs to refer to a piece of data located outside the cache, it will have to copy all the data it has modified back to RAM, then reload the cache. Fast operating systems will do their best to make sure that data used by specific programs are generally located fairly close together, so that it will reduce the number of cache misses. So your RAM will generally be fairly spread out with fairly dense clusters of continuous memory being used by a single program."], "text_urls": [[], [], []], "score": [9, 4, 3]}}, {"q_id": "5mll09", "category": "Repost", "title": "Why did Obama win the Nobel Peace Prize?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dc4g8e1", "dc4g7sp", "dc4gc39", "dc4i5e5"], "text": ["The 2009 Nobel Peace Prize was awarded to United States President Barack Obama for his \"extraordinary efforts to strengthen international diplomacy and cooperation between peoples\". The Norwegian Nobel Committee announced the award on October 9, 2009, citing Obama's promotion of nuclear nonproliferation and a \"new climate\" in international relations fostered by Obama, especially in reaching out to the Muslim world.", "It's a complicated matter but Obama was awarded the Nobel Peace Price in 2009 because the committee said that him and his administration did a lot to reach out to the Muslim world and his work with nuclear nonproliferation (not producing as many nuclear weapons) Needless to say, this did have mixed reactions.", "After the Bush administration, which pursued a very unilateral policy, it was thought that Obama's foreign policy would emphasize international cooperation and less militarism. It was awarded \"for his extraordinary efforts to strengthen international diplomacy and cooperation between peoples\". The Nobel Institute recently admitted that the award didn't really have the effect they had hoped for.", "Officially he won it for the reasons others have listed. Unofficially it was a FU to George W Bush. President Obama had only been sworn into office about a week before nominations were closed so he had no time to do anything to promote peace. Maybe it was a few weeks. I forget when the nominations were actually closed, but it was a relatively short time. If Hillary Clinton had won the presidency in 2008 they would have given it to her. The committee that awards the prize is appointed by the Norwegian government so there is naturally some political motivation involved."], "text_urls": [[], [], [], []], "score": [7, 3, 3, 3]}}, {"q_id": "5mlxwk", "category": "Repost", "title": "When a piece of music is \"remastered\" what actually takes place?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dc4ml7o", "dc4j929"], "text": ["they take master stems of old songs and add post production effects and processing that is popular at the current time of remastering. listening to original black sabbath albums you can really hear how muddy everything sounds because they lacked proper equipment, time, and money to do things such as recording each individual instrument, vocal, drum head which is fairly common now. a lot of bands back then ONLY had a 4 track recorder and had to make that work in one way or another (look into how fucking arduous recording queens vocals were, seriously) this sound is IMO better than the remasters. the remasters sound very crisp, you get a lot of high end popping out in things such as cymbals and guitars tend to cut through a little bit more. low end on kick drums is usually emphasized as well since people today LOVE them some FUKIN HARD HITTIN KICKS. this is all done with modern eq's, compressors, and a whole variety of effects that weren't available back then. i even think theres a sample delay used on the harmonica for The Wizard because its very, very wide on the remasters. all of these things are neat and all but dont necessarily fit the image or tone of black sabbath i feel, since that muddiness kinda made that era of music what it was. those in charge of the remasters are still very talented though and i'd wager that a lot of people in charge of mastering are just given a check they cant refuse from some of the huge labels that own the rights to that music. hope this helps!", "When music is recorded, it is normally recorded as multiple tracks. These tracks are then mixed down to the final recording you hear on the media you buy. 'Remastering' means that you take those master tracks and remix them to create a different final mix. In the modern day, remastering is also sometimes used to refer to taking source material and digitally re-processing the sound. For example, if you've got a recording from the 30s it's unlikely you'll have useable master tapes to reproduce the song as above. So instead you take what recordings you do have and send them through digital filters to remove artifacts and change the overall sound of the recording."], "text_urls": [[], []], "score": [7, 3]}}, {"q_id": "5mnf5l", "category": "Repost", "title": "The basic relationship between Christianity and Judaism, and their respective holy books", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dc4w9aq", "dc4ujv7", "dc4umw2"], "text": ["So around 3500 years ago, a tribe of people began to exist in the middle east, and they began to create a holy text. This text gradually became what is now called the Old Testament of The Bible. The oldest parts of the Bible date from that time, but new parts continued to be added. This people eventually came to be known as the Jews. Among the holy texts was the idea that one day, a special savior would come along--the anointed one, the messiah, the christ. Every once in awhile, some Jewish guy would claim to be that person. This particularly happened when the Jews were in a bad situation. About 2000 years ago, at the time that the Roman Empire conquered Jewish lands, it was an especially bad time, and there were multiple men who claimed to be the messiah. Jesus was one of them. Some Jews thought he was the messiah, most did not. Eventually, the group who thought he was the messiah broke off from Judaism and formed its own religion, Christianity. They used Jewish holy books, which they now called the Old Testament--texts pre-dating the arrival of the messiah. They also created new holy books, which they called the New Testament, which they see as superseding the Old Testament laws. The Jews continued along with their own religion and own texts. Jews don't believe in proselytizing, so Judaism stayed a small religion primarily composed of the descendants of Jews from generation to generation. Jews continue to believe that one day a messiah will come, but that belief is only a very minor part of what Judaism is, so it's not something most Jews talk about or spend many prayers on. Christianity believes in proselytizing, plus eventually gained the adherence of the leaders of the Roman Empire, resulting in Christianity growing tremendously. Jews continue to use the Old Testament as their holy books, but of course don't call it the Old Testament, because that's a Christian designation. Plus the Jewish Old Testament contains slightly different texts than the Christian Old Testament does. And different Christian denominations have selected somewhat different books for their Old Testament, anyway. Like, one book, the Book of Esther, is part of the Old Testament for some Christian denominations, and not others, for example. And for Jews, the most important of the holy books is the Torah--Genesis, Exodus, Leviticus, Numbers and Deuteronomy. Those are part of the Christian holy books, but not as centrally important as they are to Judaism.", "Jesus was a Jew. The first half of the Christian Bible, the Old Testament, is pretty much the same as the Jewish ~~Torah~~ Tanakh.", "Judaism predates Christianity by many years (thousands). Jesus was, in fact, Jewish. The Jewish holy book is referred to by Christians as the Old Testament. Christians believe the New Testament, which is basically the gospels of the life of Jesus, takes precedent over the Old Testament. Christians believe that Jesus was the long-promised Messiah. Jews believe he was just another false prophet."], "text_urls": [[], [], []], "score": [14, 4, 4]}}, {"q_id": "5morer", "category": "Repost", "title": "What happens when your foot \"falls asleep\"", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dc5arnm"], "text": ["The simple version is a nerve was temporarily pinched, preventing full feeling from reaching the rest of the nervous system. The nerves that innervate your muscles are different than the nerves that innervate your skin which is why you can still move your foot, despite not having full feeling in the skin."], "text_urls": [[]], "score": [13]}}, {"q_id": "5mpgo0", "category": "Repost", "title": "what is it about eggs that make them so useful in baking?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dc5cybg", "dc5czfw", "dc5czyk", "dc5cx6c"], "text": ["They stick things together. Try making mince meat burger patties without them and they just fall apart. Also the whites are great for lightening mixtures; just beat them up until they're a light foam and fold the result into a cake mix to make more much more air inside the cake. The extreme is meringue which is essentially egg whites and dissolved sugar baked hard.", "You know how when you crack an egg it's all gushy but when you cook it, it gets hard? Eggs work the same way in cakes, so when you mix them into batter & bake it, the eggs turn solid & give your cake structure. There's also fat in eggs, which adds flavor/richness the same way butter & cream do in food. Now I want cake.", "Took culinary courses. Eggs can act as an emulsifier, to prevent seperation in certain dishes and desserts. It is also used to help provide support in pastries and desserts as well.", "Apparently its the stickyness. It helps hold the pastries together and not fall apart. That's what I was told from a friend."], "text_urls": [[], [], [], []], "score": [13, 11, 5, 3]}}, {"q_id": "5mqthp", "category": "Repost", "title": "How does youtubers gets money from videos they uploaded? Does it per view?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dc5n33y"], "text": ["On average YouTubers get paid $2-$3 per 1000 views. However, most YouTubers have other sources. The first one is sponsored mentions - a YouTuber will use a product from a certain company and the company will pay them for it. The second method is merchandise. This is when they have T-shirts, hoodies e.t.c. they'll sell and the money is split between the YouTuber and the website they are selling their items on. Finally, they have is affiliate links. This is where a company which sells items online will give the YouTuber a link for a product or possibly the site. Whenever something is bought using that link the YouTuber gets paid a certain amount."], "text_urls": [[]], "score": [4]}}, {"q_id": "5mupr7", "category": "Repost", "title": "Why are there no parachutes in planes as a security measure?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dc6hxkf", "dc6i5t4", "dc6j9nh", "dc6i1gf", "dc6i0xo"], "text": ["because it's kind of hard to have 300 people that don't know jack about putting a parachute on try to do it with the plane falling out of the air. and it's pretty lethal to jump out of an airliner going 500mph, even if you're a professional skydiver. and if the pilot was in control enough to slow the plane down to under 100mph, when it's safe to jump out....he might as well just guide it in for a landing.", "Because they'd be completely useless in any real emergency. The vast majority of accidents take place during takeoff and landing, at heights too low for parachutes to work (and happening too fast for anyone to even put on a parachute in the first place). For an accident at a higher altitude, parachutes will still be useless for anything catastrophic involving sudden cabin depressurization, because you'll pass out if you leave your seat (since you'll have to take off your oxygen mask). The only time a parachute might be useful is a situation where you have enough time to get everyone in the plane to put them on and exit the plane, and for a couple of hundred people (including children, infants, the elderly, and the infirm), none of whom have ever parachuted before, that's probably going to take a couple of hours, minimum. There's no situation I can think of that both takes a couple of hours, and is also safer to parachute out when you have no idea what you're doing with a parachute. Passengers are much safer staying in the plane as it attempts a controlled landing. And that's all ignoring the cost of carrying around all of that extra weight. Ticket prices would probably double, and almost no one would fly.", "It would be heavy, meaning added fuel consumption/expense for every single flight. It would be expensive to implement and expensive/time consuming for maintenance. It would take up a lot of space on the airplane. Passengers are not trained in their use nor could reliably be trained for various emergency circumstances in a short period of time. Commercial airlines fly too fast and too high for practical use of parachutes. Most accidents happen during takeoff and landing, when parachutes are useless. **TL;DR:** Impractical and expensive. Very unlikely to make any difference.", "This has been on TIL. Most accidents occur during takeoff and landing, where parachutes are useless.", "Most accidents happen during take iff and landing. Neither of those scenarios allow enough time to use parachute properly."], "text_urls": [[], [], [], [], []], "score": [36, 14, 6, 3, 3]}}, {"q_id": "5mvmhy", "category": "Repost", "title": "Why is your body more sore two days after a workout instead of the day after?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dc6pfre"], "text": ["DOMS is delayed onset muscle soreness and goes back to our survival backgrounds when hunting would mean exerting our bodies for days at a time and so we wouldn't feel the muscle soreness until a while after so that we weren't likely to be in a dangerous situation."], "text_urls": [[]], "score": [3]}}, {"q_id": "5mw5z1", "category": "Repost", "title": "Why do giants in movies always seem to move so slowly compared to human sized characters?", "title_urls": {"url": []}, "selftext": "You always seem to see characters under the shadow of a giants foot but they somehow slip away because the giants foot comes down so slowly. Surely they should be able to stomp down just as fast as us stomping on an ant?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dc6vk9l"], "text": ["By the square-cube law the bigger an animal is the more it has to work to move. The amount of mass to move increases much faster than the number of available muscle fibers. Additionally, can you imagine what it would do if it could? If you've ever picked up a light object after lifting weights for a while you know how much harder you can swing things around when you're suddenly using more force than you normally would. A hundred foot tall giant putting his foot down as relatively hard as a human would be like dropping a bomb. The only thing I've seen take notice of that well is the old Prototype games, where your suddenly superpowered character cracks pavement when he runs."], "text_urls": [[]], "score": [6]}}, {"q_id": "5mxdop", "category": "Repost", "title": "how can a single speaker diaphragm create an unlimited number of sounds/frequencies at the same time?", "title_urls": {"url": []}, "selftext": "I understand how it can vibrate at a single frequency, but they produced 10's if not hundreds at once, voices, guitars, pianos, all in crystal clarity.", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dc71ws8", "dc7cfb6"], "text": ["Look what happenes when you add multiple to another. The result is yet another wave. For many of the resulting waves the speaker can produce a wave that is close enough that we can't distinguish them easily. URL_0", "Sound is all just waves, right? When waves interfere with one another, they combine to [an average]( URL_0 ). Each possible sound ever, can be expressed mathematically as the combination of its component sound waves. So, we give the speaker the ability to produce a range of waves, then tell it the mathematical function for the combination of the waves. It then produces the average wave for your listening pleasure."], "text_urls": [["http://wolframalpha.com/input/?i=sin%28t%29+%2B+sin%283*t%29%2F3+%2B+sin%285*t%29%2F5&amp;x=0&amp;y=0"], ["http://hyperphysics.phy-astr.gsu.edu/hbase/Sound/imgsou/int5.gif"]], "score": [9, 5]}}, {"q_id": "5myvxn", "category": "Repost", "title": "Why do Auctioneers speak the way they do?", "title_urls": {"url": []}, "selftext": "I assume it's to give the buyers a sense of urgency, but are they even saying anything?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dc7cmf4", "dc7fosh", "dc7ma3c", "dc7jz20", "dc7ig6q", "dc7cavz", "dc7pduw"], "text": ["The heart of the auctioneer chant consists of two pieces of information. Piece of information #1: The current amount bid on the lot in question. Piece of information #2: The next highest bid increment. If you want the item, you have to offer that second number. When someone does, that becomes the new #1 piece of information, with the next increment being called. Styles vary from place to place, but the stereotype auction chant includes a lot of 'filler', which is really just there to make it feel like something is happening, when really the auctioneer is just trying to keep dead air from happening while waiting for someone to make up their mind and raise their card. Some try to make this filler more useful, like dropping information about the item, reminding people if remote bidders are still in or out, and things like that, but really it's just to keep awkward silences from forming.", "I assume here that we're speaking of the [auction chant]( URL_0 ), yes? Individual auctioneers develop their own style and patter, but it's still immediately recognizable as auction chant. Yes, the reason they speak that way does have to do with \"urgency,\" but it's *not* just about artificially creating an atmosphere that the auctioneer hopes will encourage people to bid. There are far more practical things going on. The auction chant is all about delivering just two pieces of information, distinctly, as quickly as possible: the current bid, and the next bid. All the rest is basically filler. It's okay that it's almost impossible to understand the filler as long as the *numbers* are distinct. Why do things that way? Because it's the best way to move as many lots as possible, as quickly as possible. This is particularly important in commercial auctions (e.g., livestock, cars), where there is often a truly *staggering* amount of goods, both in volume and value. Also, in many cases, simply getting all of the buyers and sellers together in one place can be a real trick. For things like livestock and other commodities, simply getting everyone together in one time, at one place, so that transactions can be completed on the spot, is a *huge* logistical undertaking. Every day a buyer/seller spends at the auction is a day they're *not* spending on whatever business brought them there in the first place. If everybody can only afford to be in town for a day or two, the auctioneer had best be able to move *everybody's* inventory in that day or two. Further, the auction chant has kind of become a thing in its own right. It's how people *expect* auctions to be conducted, even if it's only a single-item, (e.g., public sale of a house with no contents, etc.). The people have come out to an auction, and darn it, they wanna hear the auctioneer do his thing. So tradition has a lot to do with it, particularly in smaller auctions. Of course, none of that applies to auctioneers at *very* high end houses like Cristie's, Sotheby's, etc. Those guys seem to make a point, as a matter of class/style/whatever, to hardly speak at all. As they don't really have to: there are only a few items up at any given time, and they're of sufficient cost and/or uniqueness that the items themselves generate all the interest/urgency needed. Also, that godawful, plebian yelling is just *so* unsophisticated. What is this, a fish market? /s", "I worked as an auctioneer as well as went to auctioneer school. It is about creating excitement and in retail auction it can have a significant effect on how much you get for an item. As an example of showmanship making a difference, I have done auctions where you are required to sell everything from an estate (often times because there is in fighting between heirs). So nearing the end of the auction you have crap like a box of stuff that was under the kitchen sink. You can't get anyone to pay a dollar, keeping asking for it is going to kill the mood. You pair it with a few more boxes of crap and ask for a dollar. The crown is dead, you are loosing them. I take a dollar bill out of my pocket, throw it in the box and now you will get a chuckle and the very same pile of boxes will bring five bucks. More importantly you have won back the crowd. That is increases what you get on subsequent boxes.", "It seems to be confined to certain types of auctions and places. Here in the UK, for example, you'll hear something akin to the sort of thing I assume you're talking about (continuous, near-incomprehensible gabbling) at, say, some cattle auctions - but go to the average general or fine arts auction, and you'll get something very different; much clearer, with the auctioneer often working the room with comments, observations and even jokes to get the best price (of which the auction house, naturally, takes its not-insignificant cut; good selling = more profit). I can see why you might want to keep talking without saying much when, basically, you're selling the same item over and over again (\"Oh look, it's another bullock!\"), and need to fill time; outside of that, though, personally, I can't help feeling that the US-style incomprehensible auction drawl is often basically a \"traditional\" affectation that serves little to no purpose _per se_.", "I once saw an auctioneer who couldn't talk fast enough so after every increment he'd go grluuuuuuh (he'd roll his tongue on the 'l').", "I'm guessing because an auction is a fairly fast-paced event so they need to be quick and not linger on bids for too long. And it keeps the excitement alive.", "As many have said, it's about adding urgency, avoiding silences, and generally keeping people engaged and therefore more likely to bid. But the auctioneer-speak has also become somewhat of an art form in and of itself. My granddad used to run a dairy farm, but even after retiring he'd sometimes take me to bull auctions to watch the auctions and listen to the various auctioneers. A lot of people would go for the same reason; it was almost like going to an auctioneering competition as much as it was going to an auction. Also, it's so they can sound lit as fuck over a good beat: URL_0"], "text_urls": [[], ["https://en.wikipedia.org/wiki/Auction_chant"], [], [], [], [], ["https://www.youtube.com/watch?v=xzIw5GSBzPo"]], "score": [233, 184, 32, 10, 5, 4, 4]}}, {"q_id": "5mz37c", "category": "Repost", "title": "How does salt melt snow and ice?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dc7ifhz", "dc7e0kw"], "text": ["Think of water molecules as shoeboxes. When they're thrown around haphazardly, that's liquid water. When they're stacked together neatly, that's solid ice. The thing is, these shoeboxes are vibrating. The warmer the temperature, the stronger the vibration. If the temperature is too high, that nice orderly stack of shoeboxes gets shaken apart into a disordered pile - it melts into a liquid. Now mix in some salt - throw a bunch of golf balls into your pile of shoeboxes. Now when you try to stack them together, there are golf balls getting in the way and causing the boxes to slide around. It's much harder for them to stack up neatly, and even a tiny bit of vibration is enough to collapse the stack. In order words, mixing salt into the water makes it much harder for the water molecules to line up into solid form. It therefore lowers the melting point of the ice below 0 degrees Celsius, and the solid crystals of water collapse back into liquid form.", "Salt is composed of NaCl. When NaCl meets with water, it forms a compound with a much lower freezing point that the freezing point of water. So, the new pseudo-ice compound melts."], "text_urls": [[], []], "score": [27, 6]}}, {"q_id": "5n0mij", "category": "Repost", "title": "What language are computer programming languages written in? What was the first programming language written in?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dc7qykw"], "text": ["Modern computer programs are written in a huge variety of languages depending on the purpose. Examples are Java, Python, C, C++ etc. All of these are essentially sets of instructions that tell more basic bits of software what to do. This cycles all the way back to \"machine code\". Machine code is literally the 1001 0101 binary that you've no doubt seen before. This essentially tells specific bits of the physical computer hardware whether to be on or off. This has certain outcomes such as sending a bit of information to your screen."], "text_urls": [[]], "score": [3]}}, {"q_id": "5n2vwx", "category": "Repost", "title": "The controversy surrounding GMO's and why are they so stigmatized.", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dc8ao8n", "dc8kzxo", "dc8ayzc", "dc8bqzv", "dc93alh"], "text": ["There is no controversy around GM crops outside of anti-science and conspiracy theory nuts. The scientific consensus on GM crops is more solid than on climate change.", "So far, no one has answered the question, so I'll try to play advocate for the anti-GMO people: - Being genetically modified, some people are afraid that consumption of GMO crops will have as yet unknown health impacts or cause allergic reactions. - Farms will be even more at the mercy of big corporations, if they are forced to buy seed with copyrighted DNA from Monsanto etc in order to stay competitive. - Reduction of diversity: There is a fear that crop diversity will be further reduced by the introduction of GMOs, opening up the risk of widespread crop failures if a new disease comes along. - \"Normal\" farms operating next to GMO farms might get sued for using copyrighted DNA because the GMO plants have spread to their farmland. - Making crops more resistant to pesticide/insecticide through genetic manipulation could lead to farmers spraying more of these poisons on the crop, which isn't all that great for consumers or the the ground water. So, these are the main arguments stated by the opponents. Did I miss any? I myself am not anti-GMO, but I felt this thread was a bit one-sided with everyone circle-jerking about how everyone with half a brain HAS to be pro-GMO", "So, the short answer is that, from the perspective of the fearful, a GMO is a novel product and should be treated as such. With traditional foods, there's a long and extensive history where we've evaluated them for their nutritional benefits and costs, but with foods that are genetically engineered, there can be a large enough change between the base food and the GMO that we can't safely assume they have the same benefits and costs as their base organisms. But, quite frankly, those GMO foods are potentially dangerous enough that they triggered those reactions in some tremendously smart people well before the general populace was exposed to them. They have been more rigorously studied for short an long term side effects than any other foodstuffs available to our populations. To the best damned ability for us to figure it, the ones allowed for human consumption are completely safe. And, quite frankly, the anti-GMOers have a(n accidental) point. The foods we eat deserve a much more rigorous study than they've received. Without multi-generational double blind studies, there's no way to completely rule on how safe any given food is for humans. And those studies have never, and never can be, done.", "Whether or not the GMO food itself is safe or not isn't really the issue for me. One of the biggest concerns I have is (let's take corn for example) that these crops have been engineered to withstand the haphazard application of more and more toxic pesticides. Also Bt corn which produces it's own toxins to kill certain insects. Problem is that we are seeing these insects developing resistance just a short time in and also having possible adverse effects on non-harmful insects. Bottom line, don't worry about whether or not the food itself is going to hurt you. Worry about the side effects from the development of these crops and monoculture in general. Sorry it's late, I'm tired and rushed through this.", "Here is a short list of reasons why people are against GE crops, followed by an explanation of why they are not legitimate. All of them are \u201cmanufactured\u201d \u2013 they are the end result of concerted efforts to discredit biotechnology. Organic farmers have a financial incentive to convince consumers that \"GMOs\" are bad. \u2022 Patents: Seeds have been patentable since the 1930s. Many non-GE crops are patented \u2013 odds are you have grown patented strains in your garden. \u2022 Monoculture: Most non-GE crops are grown in monoculture, because higher yield can be obtained. \u2022 Diversity: All seed developers cross GE traits into multiple strains of crops. GE crops have the same amount of diversity as their parent strains. \u2022 Corporatism: The seed market, by all accounts, is highly competitive overall. A few giants (DuPont, Monsanto, Syngenta) have cornered the market on certain crops (corn, soy, cotton, sugarbeet, canola), but there are dozens upon dozens of seed companies operating in the US and Canada to choose from. Also, these companies all sell organic seeds as well \u2013 so labelling/banning GE crops doesn\u2019t actually help anyone avoid products from big corporations. \u2022 Unnatural traits: Essentially every crop has been modified to the point where it is \u201cunnatural\u201d \u2013 food crops are further, genetically, from their pre-historic relatives than Shih Tzus are from coyotes. \u2022 Hurting small farms: The argument that genetic engineering hurts small farmers doesn\u2019t hold up to scrutiny. Farmers are not obliged to purchase GE crops. Small co-ops still dominate the North American market, and farmers in developing countries report great success with products such as Bt cotton."], "text_urls": [[], [], [], [], []], "score": [30, 12, 9, 5, 3]}}, {"q_id": "5n3o78", "category": "Repost", "title": "How bad is global warming right now?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dc8i501", "dc8qf9v"], "text": ["This question has been discussed in [this]( URL_0 ) thread recently. Going through those posts might answer your question.", "It's mostly referred to as global climate change AFAIK. For good reason too. Just one instance of evidence would be climate and weather patterns becoming more 'extreme' worldwide, not necessarily temperatures rising universally. More frequent and more severe droughts, floods, forest fires, tornados happening where it never occurred before. It's pretty bad but probably manageable if world leaders cooperate."], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/5gzhbd/eli5_what_is_the_current_status_on_global_warming/"], []], "score": [3, 3]}}, {"q_id": "5n3y0t", "category": "Repost", "title": "Why are GMOs supposedly bad for you?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dc8ideu", "dc8hlgo", "dc8nb7n"], "text": ["Seems most people here haven't really read your question. I'm pro-GMO, but these are some of the arguments I often encounter. 1) It's not natural. Basically,a general belief that humans shouldn't meddle with things that are part of nature, and that nature is simply better than anything we can accomplish. 2) It's new. Basically, the general belief that because it's relatively new, we can't have studies it's effects over many decades, because they didn't exist yet. 3) Association with the agro-industrial complex. Basically, GMO's are often part of the big agro industry, with pesticide use and heavy cultivation of fields. 4) Bad science. Though the scientific consensus in favor of GMO's is strong, there are contrary studies, of varying quality and thoroughness. Think the Seralini affair and all that.", "Quite simply, they aren't, so the people *claiming* they're bad for you are either lying or misinformed and spreading misinformation and fear-mongering. Eating GMO foods does not cause ill effects. The food DNA doesn't recombine with your own any more than non-engineered food. In fact, GMO foods can often be *better* for you than non-GMO foods, such as the nutrition added to golden rice using genetic technology.", "There is nothing fundamental to genetic modification that makes food dangerous. It's important to understand that humans have been genetically modifying plants and animals for thousands of years - practically all food that humans eat are genetically modified. The difference is that genetic modification used to be carried out through selective breeding (a slow and indirect process) whereas we can now carry out genetic modification that is faster and targeted by directly modifying the genetic information of plants (or animals). But the result is pretty much the same as the genetic modification that humans have been carrying out for thousands of years, it's just more powerful. That's not to say that there are absolutely no risks with GMO. It is of course completely possible to modify an organism to make it harmful, just as it is possible to modify an organism to make it beneficial. There are also some environmental and socio-economic concerns that some people have with GMO. But none of these problems are necessarily intrinsic to genetic modification."], "text_urls": [[], [], []], "score": [13, 12, 3]}}, {"q_id": "5n4crx", "category": "Repost", "title": "How do computers read binary if thats all their software consists of?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dc8kfuf"], "text": ["Because computers aren't just software, it's hardware too. The CPU contains circuits that are hardwired to decode the software instructions and execute them. For example, lets look at the simple CPU instructions `ADD r1 r2` which means \"add the value stored inside register 2 into the value stored inside register 1\". This instruction has some binary representation. The CPU has a circuit that interprets this command as \"ADD\" according to that binary representation - it signals one circuit that it should take the values that are currently stored inside registers 1 and 2 and send them to the Arithmetic Logic Unit (ALU). It signals the ALU that it should perform the addition function on its two inputs. Then it signals another circuit that it should take the output value from the ALU and store it back to register 1."], "text_urls": [[]], "score": [5]}}, {"q_id": "5n5rlc", "category": "Repost", "title": "The difference between a psychopath and a sociopath", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dc8utw1", "dc9187g", "dc9aszs", "dc8xtmk", "dc8yg3n", "dc924wr", "dc930ik", "dc8x2tp", "dc9c3b4", "dc9bemq", "dc97bt6", "dc9e5n3"], "text": ["Sociopath and psychopath aren't official medical terms and so don't have a clear, explicit definition, or a direct mapping to a medical concept. The way they're used can vary depending on the person using them. Usually they'll either be used interchangeably, or 'psychopath' will be used to mean an especially severe or violent sociopath. There are *some* professionals who use them to mean different things; Robert Hare, a criminal psychology expert, uses 'sociopath' to refer to a condition you develop as a result of abuse, neglect, growing up in an extremely harsh and uncaring environment (eg being a child soldier or slave), and 'psychopath' to refer to a condition with similar symptoms that is more concrete and innate. But even he admits this is just a convenient way to talk about things in his writing on criminal psychology (where he's an expert) and not necessarily a hard neurological truth. The medical concept is called Antisocial Personality Disorder. Antisocial, note, does not mean introverted or shy or lonely, that's usually called being *a*social. Antisocial means more 'against society.' Antisocial Personality Disorder/'sociopathy' is defined by an inability to conceive of other people as actual people, extremely muted social emotion, exaggerated and uncontrolled nonsocial emotion (eg something that would make a normal person mildly irritated will make them seethe with rage), and usually attributes of narcissism (\"everything other people say and do is secretly about me, if anything bad happens to me it was other people being jealous and malicious because nothing is ever my fault\").", "These are all great answers, but I would like to underscore the first point in the top comment: These are not official or clinical terms in the field of psychiatry. A person can't be \"diagnosed\" as a psychopath. Rather, these are social labels that people use to define abstract concepts of complex personalities. Naturally, that means that they overlap a lot. A lot of people have mentioned Antisocial Personality Disorder as mirroring cultural ideas of sociopathy, but I haven't seen anyone mention Conduct Disorder. CD is probably the closest clinical relative of psychopathy, like APD is to sociopathy. It's your basic toddlers-drowning-kittens type of thing, and only presents from a very young age. Like most personality disorders, this is also not something that can be easily handled by medication. I would *heavily* hesitate (Edit: flat out refuse) to relate general psychosis (ie. schizophrenia) to psychopathy, since the two definitions just don't overlap enough. Doing so only increases stigma on an already vulnerable group, who are much more likely to be victims of violence than perpetrators. Just my input as someone who has worked with these populations.", "My shrink told me the following once: A sociopath thinks what he's doing is right, even though it's considered generally wrong by society. A psychopath knows its wrong but doesn't care or doesn't think there really IS a right or wrong in the world. A psychopath thinks of people as furniture to be moved out of the way on any whim, which leaves them prone to climbing the corporate ladder, which is why so much of our commercial society is fucked up.", "The distinctions between 'sociopathy' and 'psychopathy' has been widely debated in the field of Psychology due to the very issue surrounding whether 'sociopathy' is an officially diagnosable term. Psychopathy is firstly recognized as the neurological imbalance and lesions within the amygdala, the part of the brain that controls fear and judgment. With that in mind, those diagnosed with psychopathy primarily lack general empathetic abilities; the ability to understand and comprehend hurt, grief, love, and affection, as well as the desire to experience thrill-seeking emotions, often to 'compensate' for the lack of other 'basic' emotions that they lack. Psychopaths are often greatly misunderstood due to media accounts of serial killers, manipulators, liars. Whilst they most certainly have the ability to deceive and manipulate, only a very small fraction of diagnosed psychopaths are dangerous. Generally speaking, psychopaths may live their lives without causing pain or harm to others, although can be masters of manipulation due to their lack of empathy, guilt, or fear. Bankers are currently statistically rated to have the most psychopaths in its profession; as well as thrill-seeking tendencies, money, achievements, status, ego, and power are often viewed as a desire for those with such traits. They are able to reach goals through the lack of hesitation and perceived fear. Now, onto Sociopathy. Again, is it an officially diagnosed term? Or is it a pseudo-scientific, watered-down variation of the term, 'psychopathy'? The current DSM categorizes psychopathy as a variation of an antisocial personality disorder prevalent to biological factors. 'Sociopaths' are often vaguely described as similar in traits, although its root causes are based on environmental factors (such as levels of childhood trauma/abuse/grief, etc) in which cause, could also then be contributed to such disorders as 'post traumatic stress disorder', which also causes the same perceived traits as 'sociopaths'. In which case, psychopathy is more clearly definable in terms of the DSM, as a form of an antisocial personality disorder, whereas Sociopathy is often confused with a byproduct of past environmental trauma. Whilst there is a rather clear difference between the both disorders, with a rather similar outcome, I believe there needs to be more extensive theorized studies in order to strengthen the legitimacy of the term, 'sociopath'. Hope this helps.", "Although Psychopathy and Sociopathy are often used interchangeably Psychopathy is not regarded as the same as anti social personality disorder in psychpathological/forensic/psych literature. ASPD shows a pretty common pathway from ADHD to Conduct Disorder to Substance Abuse to ASPD. It also seems to have a much bigger nurture component than Psychopathy. Take a super impulsive, poorly self regulating kid put him in a terrible home life and your likely to get ASDP in the adult. Psychopathy on the other hand seems less determind by nurture. Psychopath born in a bad environment = jail, Psychopath born in a nurturing environment =CEO. The main difference between the two are what's known as low prosocial traits: callousness, lacking empathy (although not the theory of mind kind which can be impaired in autism), lacking remorse. ASPD folk can often report feelings of guilt or shame. Interestingly although the DSM doesn't recognise Psychopathy in adults as seperate from ASPD the most recent edition DSMV does aknowledge a subtype of conduct disorder in teens (the usual precursor to an adult ASPD diagnosis) which is characterised by low prosocial traits. So they're kind of aknowledging the difference.", "The short version from my psych professor years ago: A psychopath doesn't know right from wrong. A sociopath knows, but doesn't care.", "While not medical terms, psychopath and sociopath are used differently: Sociopath is generally someone who is particularly uncaring toward others. Often a master manipulator who only views other people as tools to get what they want. Experiences extreme feelings and emotions, but acts on them in antisocial ways, often violently. Psychopaths are people who genuinely are incapable or have extreme difficulty feeling. Like a sociopath, they have no problem using other people to get what they want, but unlike a sociopath, they have only a cerebral understanding of human emotions, and do not actually feel them. A perfect example of the contrast is Tony Soprano (sociopath played by the late and great James Gandolfini) vs Valerie (psychopath played by Beau Garrett) from Season 6 Episode 12 of \"House\". Edit: more clarity on my examples. Also, Dexter (psychopath played by Michael C Hall) would be another and slightly less obscure example.", "A sociopath is somebody with anti-social personality disorder. This personality disorder involves a complete lack of empathy - the ability to understand other people's feelings. Sometimes murderers are sociopaths, but definitely not all murderers, and not all sociopaths are murderers. Psychopathy is less clearly diagnostically defined, but generally it means someone who is not in touch with reality. A psychotic break is an event where a person does not understand the reality around them, this might include delusions or hallucinations. Someone who is psychotic might sometimes understand reality and sometimes not. Edit: since people are whining, yes, I am aware I defined psychotic not psychopath because *there is no clinical definition of psychopath*. You can't be diagnosed as a psychopath. I alluded to this in the first sentence of my second paragraph. Source: psychology post-grad student", "I have been waiting for this forever! I've studied this inside and out for about a year. They both are covered under a diagnosis of AntiSocial Personality Disorder, but they definitely have some differences (although, like other users have noted, people sometimes use them interchangably, which is not correct). Criteria for an ASPD diagnosis can be found [here]( URL_0 ). A note: regarding the nature versus nurture debate, psychopaths are generally considered to be formed by 'nature' and sociopaths are considered to be formed by 'nurture'. Psychopaths. I've met one, been abused by her, and escaped. Not fun. Psychopaths are completely remorseless. They view other people as rungs on a ladder to climb in order to gain whatever they want- money, power, etc. They will pretend to be affectionate with you while you are useful and discard you when you become a liability. They don't give a shit how they hurt you- and if they hurt you, they are aware of it. They are the ice to the sociopath's fire. They can mimic emotions and love with extreme accuracy, making them nearly indistinguishable from the real thing. They don't feel nervousness or anxiety- they are unflappable. Due to their lack of conscience and their view of other people as tools, they are extremely manipulative. Speaking from personal experience, they can make you believe that left is right. They tend to have an extreme sense of self- preservation (some will say otherwise, but the psychopath will not risk their neck). In terms of serial killers, psychopaths tend to be the organized killers. Sociopaths, on the other hand, *tend* to be made through circumstances that cause them to become this way. They're very reckless, and tend to be adrenaline junkies. They're the type of person that other people view as unhinged. Their negative emotions tend to be cranked up to ten, so pissing a sociopath off is an extremely dumb thing to do. Unlike psychopaths, they have the capability of having a conscience, but it's a pretty small one. Correct me please if I got anything wrong!", "A great book I read called the \"Sociopath Next Door\" details stories of some sociopaths. One that stood out to me is the sociopath driving to an important work meeting then realizes he forgot to feed his dog and his dog will likely die. The pure calculations the sociopath creates to justify his actions of not stopping this meeting or even contacting a friend (Sociopaths dont have true friends) to help sent chills down my spine. My friend was married to a sociopath. She found his Chrome history of gay hookup sites and confronted him with it. His response? I only got married and had kids to put a picture on my desk at work. All successful people have families.", "By no way do I work in this field of psychology or anything. I always thought a sociopath was a individual who did violent things from years of abuse neglect Things of a physical nature from society groom that person into violent. A psychopath was a individual who would do violent and obscene things that are rooted from not being able to grasp \"normal\" concepts of things like moral, love, (emotional response) because their perception is on a completely different means of compression.", "Lotta smart folks on this thread. I have a question: is it possible to simply grow out of a severe personality disorder? I was an abused child, over the top discipline from an angry Father, years of beatings, and I became detached from reality by the time I was 14. I knew something was wrong. Anyway, 18, can't take care of myself, failed relationships, ostracized, jailed, homeless for 6 years, thief, liar, con artist, drunk, lost, hopeless, trapped all the way to the age of 29/30 and then....and then clarity, somewhat, a light at the end of the tunnel to walk towards, no psychological help, one foot in front of the other, quit drinking (cold turkey, solo), been with the same wonderful woman for 24 years, honorable, stable, generous, empathetic, sane (though I hear a screw rattle at times). How did I go being public enemy # 1 to being HOA president?"], "text_urls": [[], [], [], [], [], [], [], [], ["http://psychnews.psychiatryonline.org/doi/10.1176/pn.39.1.0025a"], [], [], []], "score": [1516, 240, 37, 27, 24, 18, 18, 14, 6, 5, 3, 3]}}, {"q_id": "5n75zd", "category": "Repost", "title": "Why school buses don't have seat belts.", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dc968kb", "dc95xfm", "dc96a8o", "dc96q5c"], "text": ["School buses are already remarkably safe due to their height and weight and kids are unlikely to use seat belts correctly on them anyway. Instead, school buses rely on putting seats close together and covering them in foam so if the bus does get in a wreck, the kids will hit the foam in front of them. Adding seat belts would cost money and require more room, which means fewer kids per bus. Misuse could also result in more injuries than injury prevention. Even if we did want to put seat belts in, who would get ticketed for kids not buckling up? In a family car, the parent can usually exercise some authority over their own children and make them buckle up, but that's unreasonable to expect from a bus driver who has to drive dozens of kids around.", "The school buses I was on as a kid always had them. The kids however never actually wore them.", "In Texas there is [no money]( URL_0 ) for seat belts. $500,000/$10,000,000 actually spent on lap belts from the lap belt budget. Edit: an excerpt... \"Parents and others fighting to protect children on school buses celebrated in 2009, when Texas lawmakers earmarked $10 million to equip the vehicles with seat belts. Yet six years later, the money is gone - with less than half a million dollars ever awarded to school districts for the devices.\"", "School buses are already much safer than regular cars. Seat belt laws vary by state. In NY, they are required to be present, but not be used."], "text_urls": [[], [], ["https://www.google.com/amp/www.houstonchronicle.com/news/education/amp/Full-state-funding-for-seat-belts-on-school-buses-6540202.php?client=safari"], []], "score": [11, 6, 4, 3]}}, {"q_id": "5n94gh", "category": "Repost", "title": "What changed in technology to allow for ubiquitous quadcopter drones?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dc9mn2j"], "text": ["There's a few things. Batteries are one of the big ones. Cell phones have really pushed the development of high capacity, long life, lightweight batteries. They've also pushed the development of low power CPUs, which are essential to keeping a drone flying. Thirdly, thanks to things like the Nintendo Wii controller, tiny gyroscopes & accelerometers are also widely & cheaply available."], "text_urls": [[]], "score": [4]}}, {"q_id": "5nano2", "category": "Repost", "title": "why is the QWERTY keyboard configured the way that it is?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dca05z7", "dca08jd"], "text": ["Mechanical typewriters have a bunch of arms that stamp the paper when you push a button. If arms too close together are pressed in rapid succession they'll collide and jam up the typewriter. The QWERTY layout avoided this by putting commonly placed together letters on opposite hands and ensuring you hit adjacent buttons as rarely as possible.", "Layout is based on old typewriter (Sholes and Glidden) and became popular due Remington N.2 because it included upper and lower key letters. After this it became industry standard. It was created in 1870s and was trying created by trial and error trying to mimic most used letter pairs far away from each other when typing in English. There is even field of study that is focus on bigram (letter-pair) frequency that may have influenced the development of QUERTY keyboard."], "text_urls": [[], []], "score": [7, 3]}}, {"q_id": "5ngzhf", "category": "Repost", "title": "Where does \"lost\" weight go?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dcbg6tt"], "text": ["Fat is basically made of carbon and hydrogen. It gets combined with oxygen to make carbon dioxide and water, which you mostly exhale. This process also produces energy, which is used to power your muscles, brain, etc. Ordinarily, your body runs on glycogen, which is a starch-like compound that stores energy and is kept in your muscles and liver. Your body makes it when you consume sugar (or things that can be broken down into sugar, like carbs and fats and proteins to an extent). It gets broken back down into sugar and \"burned\" (combined with oxygen to release energy) in your cells all over your body. When you run out of stored glycogen - because you are burning more energy than you have consumed recently - your body will start to break down fats in a similar way."], "text_urls": [[]], "score": [3]}}, {"q_id": "5nls51", "category": "Repost", "title": "Why when we see a video of a computer monitor, usually you see white lines moving across the monitor?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dccgsjc"], "text": ["Most likely you are [referring to moire]( URL_0 ). Your camera uses pixels, your display uses pixels, if you use the former to record the latter, the pixels won't match up perfectly, and if your camera is close enough to see the pixels, then you will get that effect. Also, if you try to display a picture of another display on your computer, you will also get this effect; also, if you use your phone display to view your recording of the computer display, you can also get this. If you are not referring to this, then you are referring to the fps of your camera not capturing your entire display's frames at once. Also, most consumer cameras are CMOS, meaning they don't record a frame all at once, they record from top down, this can cause the top of the frame to capture a different computer frame than the one at the bottom. Also, a complete mismatch of fps to Hz also will cause imperfect recordings."], "text_urls": [["https://kylejanzen.files.wordpress.com/2012/03/moiremaker2.jpg"]], "score": [8]}}, {"q_id": "5nm9hb", "category": "Repost", "title": "why can't anyone/ thing go faster than the speed of light?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dccodv5"], "text": ["Technically, there's nothing that prevents anything from going *faster* than the speed of light, you're just not able to go *exactly* the speed of light, unless you have no mass. (There are hypothesized particles, called *tachyons*, that travel faster than light. They've never been observed and may not/probably don't exist, but they're not against the rules, as far as we can tell.) The reason why you can't go *exactly* the sped of light is all due to relativity. We know that light has a constant speed in a vacuum (called *c*). We know that because we've observed it, it's just a built-in fact of the Universe. So, think about how speed works in classical Newtonian mechanics: If I'm traveling at 50 MPH toward you and you're traveling at 50 MPH toward me, we each see the other going 100 MPH. But what if, while I'm traveling toward you at 50 MPH and I shine a light at you? Do you see the light I shine at (speed of light)+50 MPH? Nope, you still see it at *c*. This has been shown in countless experiments throughout history, and in fact things that we use every day like GPS depend on this property. For the speed of light to be constant for all observers even when they're moving relative to each other, means that things have to \"squish\" along their axis of movement (called \"length contraction\"). This is separate from the feeling you get of being pushed backwards when you accelerate. This contraction means that, in your moving inertial frame, an inch on a ruler would still be an inch to anyone else in your reference frame, but might be longer or shorter to someone else moving differently from you - and the difference would be exactly enough that if you measured the speed of light (as distance/time) using that ruler, you'd get the same results. The other person's ruler would likewise look longer or shorter to you. What's really fun is that it's not just rulers, it's clocks too. If you measured a second, it would still be a second to you, but to someone moving differently it would be longer or shorter (and vice-versa), again just enough that all measurements of the speed of light would be identical for both of you. (This leads to a bizarre feature of the Universe, the relativity of simultaneity: two different observers can disagree as to the order of two events happening, one would see event A happen before event B, while the other would see the opposite...*and they'd both be right*.) So now you know that rulers shrink when you travel. Now, to simplify things further, go back to normal driving. Say you're driving to work. If you double your speed, you get there in half the time. If you quadruple your speed, you get there in a quarter of the time. If you went the speed of light, you'd get there at the same time you left, because your ruler would be shrunk to the \"unit\" length. (And if you went faster than the speed of light, you'd get there before you left, because your ruler would go \"negative\", which has plenty of its own problems.) Remember that mass and energy are the same thing. The faster I'm going (relative to you) when I hit you, the more energy is conveyed: I hit you harder going 20 MPH than I do going 10 MPH. As force is equal to mass * energy, we can view this as me getting more massive the faster I go relative to you. The amount of mass I gain relative to you grows and shrinks in the same way as the clock and the ruler, such that people traveling the same speed and direction as me see me have the same amount of mass I always have, while you (because I'm hurtling toward you) see me having more. Additionally, since mass takes energy to accelerate, as I gain mass, I need more energy to accelerate, and then I gain more mass, so I need more energy to keep accelerating... Because the speed of light is constant in all reference frames, the mass thing also varies like the rulers and clocks do, such that if I were traveling the speed of light, I'd have infinite mass (because I would appear to be traveling in at the speed of light in all reference frames). So it turns out that if I'm going the speed of light, I have infinite mass. Moving an infinite amount of mass takes, you guessed it, an infinite amount of energy. So you can't go the speed of light unless you get an infinite amount of energy (impossible) or have no mass (i.e. you are a light particle). This is grossly simplified, and is also drawing on decades-old memories of school, and I'm most certainly not an expert, but I think I'm vaguely right in the generalities."], "text_urls": [[]], "score": [9]}}, {"q_id": "5nmdws", "category": "Repost", "title": "Why is the speed of light the fastest speed anything could ever reach?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dccm3ah"], "text": ["It's not like the laws of the Universe say \"Ok, Light's pretty fast, let's make that the harsh speed limit\". It's the max speed because photons have no mass, once you have any mass, you would need infinite energy, which isn't possible. Anything with photos move at light speed, such as radio waves. The starting velocity of the light source doesn't matter, as photos are always travellijg at that speed, they aren't accelerating to it, under normal circumstanses. Also, we right now are moving over 2,000,000 mph, take that in. Also, due to reletivity, time dilation, etc., the light from relative to P is the same as a light coming from P, so that doesn't matter."], "text_urls": [[]], "score": [6]}}, {"q_id": "5nmret", "category": "Repost", "title": "Why is is easier to sneeze when looking into a bright light?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dccp690"], "text": ["If this happens to you, you probably possess the [Photic Sneeze Reflex]( URL_0 ) also known as (ugh) ACHOO. It's similar to an allergic reaction to bright light."], "text_urls": [["https://en.wikipedia.org/wiki/Photic_sneeze_reflex"]], "score": [3]}}, {"q_id": "5nnfjf", "category": "Repost", "title": "Why does e^pi*i + 1 = 0?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dccv499", "dccv6p6"], "text": ["Probably can't explain at an ELI5 level, but here's the gist of it: e^angle*i is a rotation of a point in the complex plane (just pretend it's typical \"x is horizontal y is vertal\" for the moment) angle=0 degrees means the point (1,0). angle =90 degrees means the point (0,1) angle=180 degrees means the point (-1,0). *Pay attention to this one* angle=270 degrees means (0,-1) angle=360 degrees means (1,0). You're back where you started. Here's the deal. In the complex plane, x means \"real numbers\", y means \"imaginary numbers\". so for example (2,7) would mean 2+7i. So (1,0) means 1+0i (or just 1)....(0,-1) means 0+-i (or just -i) and so on. What is 180 degrees in terms of radians? Well, it's just pi. So e^ pi * i = e^ 180 x i = (-1,0) = -1+0i (or just -1). So now you have e ^ pi * i =-1. Add 1 to both sides of the equation, I'll leave that as an exercise for the reader.", "[this]( URL_0 ) is a great video that assumes you only know how to add, subtract, multiply, and divide, and actually ELI5's it (with pictures) the best I have ever seen, for this question. Mathematically: the function f(x) = e^(ix), when x is a real number, maps you onto the unit circle (the circle of radius 1 centered at 0+0i) on the complex plane. When x=0, e^(0) = 1, as usual. Travel \u03c0 around the unit circle from there, and you get to -1. Hence e^(i\u03c0) = -1."], "text_urls": [[], ["https://m.youtube.com/watch?v=-dhHrg-KbJ0"]], "score": [6, 3]}}, {"q_id": "5nno9t", "category": "Repost", "title": "How was the speed of light measured? I know it had to do with light and mirrors and mountains but after that I'm completely lost.", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dcd5rlc", "dcd1jvd"], "text": ["Leon Foucault (of \"Foucault's pendulum\" fame) measured the speed of light to a very high precision in the 1860s, using a variation on this experimental setup: He used a lantern instead of a laser, obviously, but the principle is the same. URL_0 Take a mirror that's rotating at a known set rate, and shine a pulse of light at it. The light bounces off the rotating mirror, out to a stationary mirror a long way away, and back to the rotating mirror. In the time it took the light to bounce out to the stationary mirror and back, the rotating mirror rotated a little bit, so the pulse doesn't end up bouncing back to the original laser/lantern. Instead it bounces a little bit off to the side. The distance between the laser/lantern and the final reflected beam can be used to calculate the time it took the light to bounce between the mirrors, and thus the speed of light.", "The idea that light had speed (rather than being something \"instantaneous\") gained momentum with observations of Jupiter. The orbits of Jupiter's moons were established for quite a while, and some astronomers started writing out tables forecasting the time each [Galilean Moons]( URL_0 ) in the same way we forecast Moon/Sun rise and set times. Once the tables were established, an odd discrepancy was noticed. The tables were off, but were off in a very distinct pattern. The times would range from being spot-on, to being late (or early) by up to (about) a quarter-hour. By some clever geometry, it was eventually worked out that this was due to changes in the distance between Earth and Jupiter as the distance between them changes due to the planets' movement in their orbits. Newton made a good estimate of 7-8 light minutes between the Earth and the Sun, for example. It was not until later that we worked out the size of the various orbits and could measure the true speed (and not just relative transit time), but that was the beginning. The experiment you are thinking of used a wheel with a series of little windows. The idea was that a lantern was set so that the light could shine through the gap each time the wheel spun and the gap was in front of the lantern. A second wheel ten miles away could be set up in a similar fashion, blocking a mirror. Noting the RPMs of the wheels each time the \"signal\" (light) remains steady (rather than flickering) against the mirror allowed the scientists to work out possible speeds of light--that is, the speed or speeds that would be necessary in order for the \"signal\" to behave as it did (blocked or unblocked). Eventually competing teams were able to come to within about 1000 miles per hour of the correct speed, this is no small feat considering their only tools were lanterns, spinning wheels, and land-survey equipment (to measure the distance between the wheels). If memory serves, one team used two wheels, the other used a wheel and a spinning mirror, but my memory may be off in that regard."], "text_urls": [["https://upload.wikimedia.org/wikipedia/commons/4/46/Speed_of_light_%28foucault%29.PNG"], ["http://lasp.colorado.edu/education/outerplanets/moons_galilean.php"]], "score": [8, 7]}}, {"q_id": "5no9ff", "category": "Repost", "title": "What is a computer server?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dcd1j8g"], "text": ["A computer. It's a computer that has a whole lot of storage space and a really sturdy processor. It also runs specific software for specific tasks. An office's file server, for example, would be a totally normal computer except it would have, say, four terabytes of storage. That computer goes on the local network and is made accessible to, and from, any computers on that same network. The employees then use said server to exchange files. They will also use Windows Server (or the equivalent) rather than Windows 7/10 due to software features."], "text_urls": [[]], "score": [3]}}, {"q_id": "5np58o", "category": "Repost", "title": "Why exactly does our perception of time change as we get older? (Years and days seeming shorter, life going by faster)", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dcd98uj"], "text": ["When you're 5, a year is 20% of your life. When you're 10, a year is 10% of your life. When you're 20, a year is 5% of your life. When you're 40, a year is 2.5% of your life. And so it goes on."], "text_urls": [[]], "score": [3]}}, {"q_id": "5nu3ot", "category": "Repost", "title": "Why are drones widely available and popular now?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dcebtft"], "text": ["Battery technology improvements allows for longer flight time. Also 3d printing technology along with better plastic materials makes it easy to create very efficient and durable propellers not to mention can be made cheaply. That's pretty much it."], "text_urls": [[]], "score": [3]}}, {"q_id": "5nuu8z", "category": "Repost", "title": "Why are the planets so bright?", "title_urls": {"url": []}, "selftext": "I understand they reflect light, because, well, they are matter, but why do they seem so much brighter than the stars? The light from the stars are farther away, of course, but once they get here, they're here? Is it merely an illusion due to the distance difference? Is it possible some of the \"stars\" I see are actually super-huge planets?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dcehvf8", "dcejcv5"], "text": ["No the star you see are not super-huge planets. But you might have mistaken on of the our 5 planets that we can see with nake eyes for a star. It's really only the difference in distance. Take venus for exemple. At it's closest to earth it's only at 38 million km. The closest star is at 4.24 light years away. That's 10.5 millions times farther aways.", "So as you know, light radiates out in all directions from a star. This means that the energy a star puts out is spread out across a sphere with a radius equal to the distance from the observer to the center of that star. For the Sun, even with the added distance of traveling to a planet and then traveling back, is much, much, much, **much** less than the distance even to the closest star. Since the entirety of the energy spreads out over this entire sphere surface, the amount of light intensity that reaches us from other stars is much less than what reaches us reflected from planets."], "text_urls": [[], []], "score": [9, 6]}}, {"q_id": "5nvaxa", "category": "Repost", "title": "Why is cold drinking water more refreshing than warmer water?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dcen76t"], "text": ["While learning to sail our crew would always have lots of water, everyday we would offer our instructor a nice cold bottle of water from our cool box and everyday he would accept but then leave the bottle on the side till it got to room temperature, after a few days I asked him why and he explained that when you drink cold water your body has to heat it up which takes time and energy, and when you drink hot water your body has to cool it down which again takes time and energy, he explained that the best way to hydrate yourself is to drink room temperature water. Although it doesn't answer the question I wouldn't be surprised if this was in some way connected to it."], "text_urls": [[]], "score": [3]}}, {"q_id": "5nwdx6", "category": "Repost", "title": "Why can some computers run videos of a game when they cannot run the actual game itself?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dcesyx5"], "text": ["To run a video of a game, which is the same as a PewDiePie episode or a SpongeBob episode.. all your computer has to do is play back the video using whatever player and codec. To actually play the game you have to render a scene, calculate lighting and graphical effects, calculate AI and what not and read player input. Most of these 60 or 30 times a second. Simply put, it's like buying a shoe compared with making a shoe?"], "text_urls": [[]], "score": [11]}}, {"q_id": "5nxvvm", "category": "Repost", "title": "Why do you have to 'safely remove hardware' before removing a USB flash drive. What exactly is happening and why is this step necessary?", "title_urls": {"url": []}, "selftext": "I've always followed this procedure but I never really understood the actual pros/cons of completing this process or not.", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dcf2icc", "dcfamde"], "text": ["Writes can be cached to memory to speed things up. This step is making sure the write cache is flushed. There's a slight risk of losing or corrupting data if you don't follow that step.", "The file index structure must be updated, not just the file itself, that is added, changed or erased. Interrupting this corrupts the file system so it's read-only next time or maybe even unreadable. Then you need to use a program to repair the file system."], "text_urls": [[], []], "score": [5, 5]}}, {"q_id": "5nybbe", "category": "Repost", "title": "Why do black lines appear over screens when you try to record them/take a picture of them?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dcf6fxx", "dcf7j7e"], "text": ["It has to do with frame rate and rolling shutters. Your camera records one line at a time - *really damn fast* but only one line at a time. Your screen also has a refresh rate, and the light behind the pixels also has a cycle rate. Normally this is far too fast for your brain to perceive. If your screen refresh rate is different than your camera's frame rate, there will be moments when the screen is in the middle of refreshing and the pixels will be black, and the camera will record black pixels. Since your camera is going one line at a time, it creates a weird rolling lines across the screen. [Relevant Standupmaths]( URL_0 ), and [relevant Tom Scott]( URL_1 ).", "This was usually a problem with CRTs. Modern digital flats have higher refresh rates making the black lines effect more difficult to capture with a consumer-grade camera. Some flats may also apply GIF-like technology, changing only what needs to change, which can remove the black lines effect entirely."], "text_urls": [["https://www.youtube.com/watch?v=3GJUM6pCpew", "https://www.youtube.com/watch?v=uzP8FFKpwQ0"], []], "score": [8, 3]}}, {"q_id": "5nyyid", "category": "Repost", "title": "If waters boiling point is 100 degrees celsius, why does it still evaporate at room temperature?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dcfb6cw"], "text": ["Rate of evaporation is depends on temperature. At 100 C, evaporation is very fast. At Room temperature, evaporation is slow. At freezing temperature, evaporation is extremely slow. Tl;DR: Water evaporates at all temperature."], "text_urls": [[]], "score": [7]}}, {"q_id": "5o0akc", "category": "Repost", "title": "Why does TV almost never \"lag\", and why can't internet to not lag the same way?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dcfmdor", "dcflqa6"], "text": ["Replace film with text. Internet works by writing it on separate pieces of paper, then taking a piece to each of your neighbors one by one. TV works by writing one large poster and hanging it out of your window for everyone to see. TV is faster (especially if you walk very slowly and have a lot of neighbors), but on the internet you can send different messages to different people (on TV we all get the same thing).", "When you use the Internet, sometimes it lags because of shared bandwidth. You and your neighbors share a connection that has a finite speed; and then the customers of you ISP in your town will share one or more outbound connections, also with finite speed. As a result, the amount of bandwidth actually available to you at any given time varies. With broadcast television signal, it doesn't have to share bandwidth. It operates on what's called \"licensed spectrum\" meaning only that television station has the right to broadcast on that frequency in your area. As a result, the TV station has a very predictable amount of bandwidth to work with. Think of it like driving home on a highway, then to your house where you have a long driveway. You can't ever be 100% sure how long it takes you to get home because traffic might be heavy or light. But you always know exactly how long it takes to get up your driveway because there's *never* any other traffic on it."], "text_urls": [[], []], "score": [9, 7]}}, {"q_id": "5o5v97", "category": "Repost", "title": "How do candles work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dcgt4ai"], "text": ["A candle consists of wax that is used as the fuel, and a wick that is used to transport the wax to the flame. The wick starts infused with wax. When you light the candle, the wax in the wick melts, and then turns to a gas, and then the gas burns by combining with oxygen in the atmosphere. That produces heat, which melts the wax near the wick. The melted wax is then pulled up into the wick via capillary action, vaporized by the flame from the wax that is already burning, and then burns itself, continuing the cycle. And since a standalone candlestick has no sides to hold in the wax, some of it will flow down the sides of the candle rather than into the wick, and be wasted rather than burned. Candles in jars don't have this problem."], "text_urls": [[]], "score": [3]}}, {"q_id": "5o5xxa", "category": "Repost", "title": "How did accents become a thing?", "title_urls": {"url": []}, "selftext": "I'm very curious on how accents became a thing(i.e. British to American, and a southern to northern). Curious on all accents from the world also.", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dcgtltw", "dch0394"], "text": ["Language is always changing, and language in distinct, rarely-interacting groups of speakers changes in different ways. Normally they're distinct because of geography, but there are also \"sociolects\", differences in how different social classes speak. When the differences between two groups are small enough we say they're speaking dialects of the same language - when you need serious translation effort for one to speak to the other we say the dialects have diverged into separate languages. You can imagine it like [a tree, growing new branches indefinitely]( URL_0 ).", "From another thread of the same question [\u2013]DiogenesKuon 6 points 3 years ago Languages tend to change slowly over time. People in the same area will tend to pick up these changes together, but those in a different area will be changing in a different way (as long as their isn't heavy spoken interaction between the two groups). Over time these collection of changes start to be noticeable, and it gets called an accent. Wait a bit longer and the changes start to be large enough that it might start to be difficult for other people to fully understand the accent, and then it becomes a dialect. Wait further still and the speech becomes mostly unrecognizable, and we start to consider it it's own language. [\u2013]the-uncle 2 points 3 years ago I would add to that the argument by Robin Dunbar he makes in his book: accents help to quickly recognize if someone else is part of your in-group (family, community, region, etc.). As such, accents are deemed to be a mean to establish trust between people on a certain level. [\u2013]DiogenesKuon 2 points 3 years ago By the same token, accents also have a long tradition of being used to ferret out spies or enemy soldiers, by forcing them to pronounce words that are pronounced differently locally. [\u2013]RikoThePanda 0 points 3 years ago Why do they develop the way that they do though? [\u2013]DiogenesKuon 3 points 3 years ago It's mostly just small random changes that often start out as a mistake. Someone moves which syllable gets accented for a word. The word is still understandable, so it's not like it's something that must be corrected, so the error continues. More people hear that alternate and copy it (either consciously because they are unfamiliar with the \"correct\" pronunciation, or subconsciously). A large number of these build up in a geographic area, and now you have an accent."], "text_urls": [["http://www.sssscomic.com/comicpages/196.jpg"], []], "score": [4, 3]}}, {"q_id": "5o7oar", "category": "Repost", "title": "How were languages first translated?", "title_urls": {"url": []}, "selftext": "I mean in terms of more modern times, so -for example, German to English. Not how did cavemen understand each other. How did they decide which words meant what? -if that makes sense...", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dch8yhx", "dchmigz"], "text": ["Imagine teaching a child how to speak. You point at a chair and say \"chair.\" Then you point at a dog and say \"dog.\" Same thing with simple verbs, you could walk or run and say the word for what you're doing at the same time. Since you'd be doing this with an adult, they'd learn a lot easier than a child, and once you've gotten a bunch of words across, they can ask you things and you can start explaining how to express higher concepts. Of course, they'd be teaching you if you wanted, and the more you each learn the faster you can explain things to each other.", "Language is something that has developed in all civilizations independently. When cultures came together physically making translation necessary, both cultures already had their own words for things. For example, water is the same thing everywhere but has different names like agua in Spanish, wasser in German, etc. it was just a matter of learning what other cultures called the same things. Some things may not exist in both places, for example, kindergarten is a German word that means garden for children and was imported by the US as a model for early childhood education. The word was adopted along with the philosophy. Sometimes, such as in the case of Algonquin, one of the primary languages spoken by people indigenous to North America, the \"winner\" in translation is about cultural dominance, in that the white settlers set up schools to re-educate Indian youth away from native languages to assimilate them. Many Algonquin words were lost in this forced translation. Sub-cultures and oppressed groups can also use language to rebel against mainstream cultures by re-labeling and/or reclaiming language used to dominate them such as queer, bitch, or fat and attaching an empowered translation of these terms."], "text_urls": [[], []], "score": [21, 3]}}, {"q_id": "5o93wc", "category": "Repost", "title": "Expand on the noise canceling please.", "title_urls": {"url": []}, "selftext": "When you guys explained noise canceling in the recent post, you said that the wave peaks top and bottom at the same time so it cancels each other out and you said its not more noise. Maybe it isnt more, but I feel like it'd just push on your ear drum More and slowly less and vibrate differently. but the push would be like a truck see pic: URL_0 More like how you push a q-tip into your ear, its not a wave, it just pushes.", "selftext_urls": {"url": ["https://s29.postimg.org/9zcsoolvb/sound_wave_truck.jpg"]}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dchl74t"], "text": ["Sound waves are mechanical longitudinal waves. In other words, the particle motion is in the direction of the wave. This can be difficult to visualize, so here's a picture: URL_0 So even though we often model longitudinal waves as transversal (like the waves in your drawing), that's just to help visualize them. When the waves cancel each other out, there is nothing. No more push. Even if the waves were transversal, the intensity of the wave is determined by amplitude."], "text_urls": [["http://www.gcsescience.com/longitudinal-wave.gif"]], "score": [3]}}, {"q_id": "5o99md", "category": "Repost", "title": "why is it that in cartoons, especially older ones like Scooby Doo, Flinstones, and The Jetsons, objects that move are noticeably lighter than the objects around them. Is this to help animators know which items to draw?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dchm5fc"], "text": ["Traditional animation was drawn on transparent sheets of celluloid, which were then stacked up to assemble a scene. So you might have a sheet for the background, a sheet for static props, a sheet for a character's body, and another sheet on top for things that actually move. Things that move need to be on top because that sheet has to be swapped out for each frame, and that makes it possible to do so without disturbing the background. Since the background is behind several sheets of celluloid (and they're not *perfectly* transparent), objects that are actually the same color appear darker. Additionally, the backgrounds were often done as matte paintings rather than cell shaded flat colors, so it wouldn't be possible to match them perfectly. Modern digital animation uses similar layered techniques, but with perfect transparency and no limits on what layers the animators can work on."], "text_urls": [[]], "score": [3]}}, {"q_id": "5ob10p", "category": "Repost", "title": "Why does the US not have a health care system like Canada or Germany for example?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dchx0a1", "dchxqun"], "text": ["Without getting into a political debate about why we should or should not have a health care system like Canada or Germany, the reason is because the political climates are different in the United States vs. those other countries. The debate is different (goal posts are moved) and the overall belief of what is required from the government is different. Also, there is higher diversity and around 5x to 10x more people in the US than Canada and Germany, and there is some question about scaling of a universal health care system.", "A lot of it stems from WW2. In the UK, for example, there was an Emergency Hospital Service nationwide to insure people injured as a result of enemy actions could receive treatment. Effectively nationalizing their health care. It was a smoother transition from that to a permanent nationalized solution. In the US, medical insurance became a perk that employers could use to keep/recruit employees. Wages were frozen, and even the ability to switch jobs was heavily restricted. But fringe benefits, like medical insurance, were still a tool employers could use to attract workers. So medical insurance as a perk, rather than a necessity, became the accepted norm in the US."], "text_urls": [[], []], "score": [5, 3]}}, {"q_id": "5ob3e4", "category": "Repost", "title": "Why does liquid stay in the straw when you cover the tip of it?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dchx9rx", "dci3rpc"], "text": ["No air can come in to replace it from the top, and the surface of the liquid at the bottom end is too strong to just break. That strength is size-dependent, though; so, with a fat enough straw, the bottom surface can break, letting the liquid spill down and out of the straw along one side while air replaces it along the other side, even while the top remains covered.", "What happens when you suck water up a straw? The act of sucking comes from your mouth, but that isn't what actually propels the water up the straw. The force that pushes the water up is atmospheric pressure aka the weight of the air above your glass of water. By sucking on one end of a straw you lower the pressure and since the pressure on the glass of water is now higher, it forces the water up the straw. When you then put your finger over the end of the straw you are sealing it. When the water tries to fall out of the straw due to gravity there is nowhere for air to come in on the finger side and so it would produce a vacuum if it were to move down, and for that same reason, the air pressure holds it up in the straw. If you were to tilt the straw and lay it horizontal, eventually the water would pour out sideways because it would open a channel for air to move along the straw to replace the vacuum."], "text_urls": [[], []], "score": [10, 5]}}, {"q_id": "5obhcx", "category": "Repost", "title": "When men get gun-shy around other men in a restroom, and can't make themselves \"go,\" what is happening to them physiologically?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dci0v9q"], "text": ["Just like their privacy and this is a very private moment. It has nothing to do with being an Alpha male or someone else's penis. It's learned. Bathrooms in homes are typically built for only one person to use the toilet."], "text_urls": [[]], "score": [3]}}, {"q_id": "5od45r", "category": "Repost", "title": "Could I essentially live off of vitamins and basic food for fuel?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dcieb90"], "text": ["It's not even all that hard. Go buy Soylent. Its a brand of meal replacement product."], "text_urls": [[]], "score": [3]}}, {"q_id": "5ofug4", "category": "Repost", "title": "How text messages sent to a dead phone will arrive once the phone is turned on", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dcj0ptb"], "text": ["The text is sent to a server belonging to your service provider and is stored, when the phone turns back on it sends the server a signal saying its on and the server sends all the texts that were received and stored while the phone was off."], "text_urls": [[]], "score": [4]}}, {"q_id": "5oieog", "category": "Repost", "title": "Why do humans require such a comprehensive and well-balanced diet while most animals thrive on a seemingly limited number of food sources.", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dcjitue", "dcjv4b2", "dcjove8", "dcjhnb8", "dcjxnho", "dcju41s", "dcjv1t2", "dckjpky", "dck36xm", "dckk8sx", "dcjx7si", "dckl18q", "dcjufn9", "dckccsy", "dcjxl6d", "dck22j6", "dckkuc5", "dcjxu59"], "text": ["It's actually the other way around. Human can survive on one of the most diverse diet. Most animal have a very specific diet and can't usually change it. If they lose that source of food, they can often be in danger. Cats for exemple, lack the ability to produce certain aminos-acid and vitamins so they can't survive without meat to give them those things. Human can produce a lot of those so they mostly need a source of energy to produce what they need. They still need specific nutrient, but those are usually frequent and a lot of source of food can provide them. People can survive on a LOT of different diet. But of course as we know more have the exact need of our body, you can specify our diet to make sure that we get all of what our body need, but that's not needed to be relatively healthy or to stay alive.", "We don't really \"require\" a carefully balanced diet. Humanity as a species and would do fine if we all raised three kids and died from malnutrition around age 35. The problem is, we don't really like that idea. And if you want to live till you're 80, you need to take proper care of your body. And thus people have figured out some pretty great and healthy diets. That's not required (just look at people who eat nothing but junkfood), but it will greatly improve the odds of growing old. Think of it as maintaining a car. If you plan to scrap it after 50k miles, you can do whatever you want. But if you want to drive 350k on it, you need to change the oil, clean the filters, properly inflate the tires, use the right fuel etc. But you only have to do that if you want it to last a long time.", "Most of the advice for well-balanced diets is to extend your life. A human doesn't need to live for 60 or 80 or 100 years, but we want to. Evolution targets efficiency, and efficiency is \"live long enough to reproduce and then die as soon as you're not useful.\" Humans can live to 40 on terrible diets, which is fine if you reproduce at 20. Most people don't want that lifestyle, so we use knowledge of medicine and our bodies to extend our life further than evolution deems necessary.", "Animals have all sorts of malnourishment problems. Humans just have enough food to be able to consider stuff like health and 'well-balanced diet'. Animals need that as well. For example cats that don't hunt need extra calcium in their food because they never eat bones (NEVER give your cat cooked bones, only raw) and so on. Without a balanced diet they will die or get sick as well.", "It's funny, I just got out of TAing a course about human brain development where we were talking about what constraints act on the development of large brains at a species level. Related to your question about diet is the question of cooking -- specifically, when foods are cooked they can allow us to extract more usable calories from them. As an adult human, your brain requires about 25% of your caloric intake daily. The development of skills like cooking as well as biological specializations to process certain foods makes our large and complex brain (relative to our body size and food consumption) possible! Not sure if this exactly answers your question, but it's interesting at least!", "If we had the same ambitions as most animals... To survive long enough to reproduce a few times, then die... Then we could worry a lot less about a balanced diet also. We could just eat bacon for 14 years or so, bang a few out, then die of a heart attack.", "Keep in mind that food intolerances are actually pretty common. 65% of adults have lactose intolerance. Most food intolerances have little or no research associated with them. Part of the reason why different cultures have different foods is due to living in different geographic environments where only certain types of of food can be grown. Prehistoric immigrants to these areas were forced to adopt to the local food sources or die", "You assumption is incorrect that animals don't need a wide variety of foods. Look up one of our closest relatives, the gorilla, for example. They eat hundreds of varieties of foods when in the wild. Think about a whale eating krill and plankton in the ocean. It also ingests every other thing in the water when it is feeding, and eats it. The problem is that in captivity it is very difficult or impossible to provide that level of variety, and we give animals supplements to compensate. The lack of variety and the lack of a need to spend hours a days foraging also creates behavioral problems for captive animals, because they don't need to and can't forage, but that's what they wired to do. Not all animals require a large variety of course. But I encourage you to reexamine the assumption in your question.", "We don't. Humans can live on a great number of different diets. That's why we can live literally ANYWHERE on the planet.", "There are two type of nutrients; micronutrients and macronutrients. The latter is what you need every day to keep going: fats, carbohydrates, and protein ( the body can actually sometimes finagle conversions between them). Micronutrients are vitamins and minerals we need in small amounts over the long run; they're what we need from vegetables and what makes \"superfoods\" super. Most carnivorous animals get their micronutrients from organ tissue- it's full of them, even though it's fallen out of style in our modern diets. That's how at least carnivores are able to get a complete diet; with herbivores I'd assume they just eat the right variety of plants.", "I should mention that the \"diet problem\" was the first problem addressed by the Simplex Method of Linear Programming. The issue is how to formulate a diet which includes all macro-nutrients and micro-nutrients in a minimum cost diet. [YouTube]( URL_0 ) The actual problem is larger than you will usually find in accessible resources.", "I lived with a guy who subsisted almost entirely on Jack & Cokes and nicotine. Not the healthiest guy but he could do it.", "to add to other people we really dont need to eat a large number of different things. we could eat the same meals every day and have the nutrition we need but we just dont like to do that when there is such a variety of foods made available to us.", "Isn't there a guy that's like 150lbs but has eaten nothing but pizza for the past ten years?", "It has to do with the amount of calories our brain requires to function is relation to our size. This can be easily compared to other animals and their brain sizes. There is a Ted talk a while back were this was greatly explained. I'll attach a link. URL_0", "Related question: How do mammals not so different form each other have such opposite diets? e.g. the grazers that only each grass and leaves (zebra, giraffe, antelope etc.) and their prey that only eat meat. (lions, leopards, wolves etc.). Isn't someone not getting their vitamin C and beta kerotene? And isn't someone else not getting their protein and iron?", "You could survive on bread and water for a surprisingly long time (assuming it's old school bread made from unrefined stuff). However, you won't thrive. A diverse diet is recommended for best results. If you're only interested in survival, and you accept some health issues to go with it, then your diet could be very narrow and limited in range. It won't kill you, probably, but you won't be in the best of health either.", "This isn't quite the case. For example, despite what some may say - you can't feed a dog cat food for an extended period of time and expect them to stay healthy, and vice versa. This is because dogs' bodies require specific amino acids. Some of these amino acids they cannot make themselves (essential amino acids). These essential amino acids are different for dogs, cats, and even humans. The same is true for certain vitamins. Considering the fact that many animals are not omnivores but strictly carnivorous or strictly herbivorous, their food source options are even further limited to specific sources of food for survival. This is why the changes in the ecosystem are very impactful on the animal community."], "text_urls": [[], [], [], [], [], [], [], [], [], [], ["https://youtu.be/96wBC6DYdXE"], [], [], [], ["https://youtu.be/_7_XH1CBzGw"], [], [], []], "score": [2451, 817, 212, 168, 71, 36, 18, 17, 13, 11, 9, 7, 6, 3, 3, 3, 3, 3]}}, {"q_id": "5ojayg", "category": "Repost", "title": "Given that we don't get colds and other seasonal illnesses just from being cold, why do most of us get sick more frequently in the winter than the summer? In other words, why or how are some illnesses seasonal rather than year round?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dcjp8c1"], "text": ["Winter is Just Better^TM for transmitting diseases. People stay inside more, which means they're closer together. People travel to visit family, taking the local strains of microbes with them. The air is dryer, which dries out the mucous membranes in your nose and throat, making them more vulnerable to infection."], "text_urls": [[]], "score": [10]}}, {"q_id": "5ojogp", "category": "Repost", "title": "when attempting to sneeze, why does looking at the sun/a light source trigger it?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dcjt4p3", "dcjt5e8", "dcjuwxt", "dcjt66o", "dcjtbli", "dcjtt8k", "dcjyf6m", "dcjvxx6", "dcju1fp"], "text": ["Imagine your nerves controlling sight as a sidewalk in a neighborhood. Normally, there's a normal supply of people walking on it and everyone stays on the path. Sometimes, there's a huge burst of people (looking at something bright). The sidewalk is so crowded that some people end up stepping on the lawn of the neighboring houses. Mr. Sneeze, living in one of the houses, sees this and gets out of his house to yell at the people to get off his lawn. The process is known as photic sneeze reflex and it affects 18-35% of the population. The mechanics behind it are not fully understood but it may be due to nerve signals being confused when there is a rapid burst from seeing bright light.", "It doesn't for everyone. About 18-35% of people are affected by this; it's called [photic sneeze reflex]( URL_0 ).", "I shit you not, there is another name for this condition that is way better than photic sneezing. It's Autosomal Dominant Compelling Helio-Ophthalmic Outburst Syndrome. Or ACHOO for short :) [Proof]( URL_0 )", "The optic nerve takes all the light information from the eyes to the brain. The maxillary nerve causes the sneeze reflex. These two nerves run next to each other for part of their course. When there is lots of electrical activity going down the optic nerve, then because they are next to each other, this activity can \"leak\" onto the maxillary nerve and push it over the limit, causing a sneeze.", "No one really knows. Some scientists say it's caused by confusion in the nervous system. Since all senses are linked, the pupil dilation response to light is translated to a nasal irritation and causes a sneeze. Other scientists suggest it's evolutionary, a trait that helped our ancestors survive in primitive life. (Clear the nose of smoke/other smells after leaving a cave to help smell threats/food sources).", "As someone who does this, I've noticed that squinting your eyes moves the sinus cavity. I imagine this affects the process as well", "I was told that looking at the sun/light normally involved looking up, which opened your airways. And that was why it helps you sneeze. No idea how true that is, though I've noticed it has the same effect in a dark room as when I'm outside.", "This is known as [photic sneeze reflex]( URL_0 ) caused by a genetic mutation that results in some sensory inputs to become \"crossed\" for example sudden bright light can be interpreted by the brain as nasal irritation.", "I actually have the same thing. Strangely enough it can apparently it can be passed down. At least my mom has it and apparently my grandmother did as well. It's kinda annoying but only because the sneezes come on so quick that I can't see what I'm going and have to pause."], "text_urls": [[], ["https://en.wikipedia.org/wiki/Photic_sneeze_reflex"], ["https://www.ncbi.nlm.nih.gov/books/NBK109193/"], [], [], [], [], ["https://en.wikipedia.org/wiki/Photic_sneeze_reflex"], []], "score": [350, 224, 53, 14, 13, 9, 7, 3, 3]}}, {"q_id": "5owa4i", "category": "Repost", "title": "Why has Socialism such a bad stigma in the U.S.?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dcmjmi6", "dcmk0xu"], "text": ["Many Americans are trained that the American dream is to work hard and become rich through that. That are also trained that socialism will steal all of their hard earned money and make the working class pay for all of the needs of those in poverty, this then removing any motivation for those in poverty to work for themselves.", "Politics and economics are not sciences. *Gasp* but I was told they were!? You got lied to. Science is able to make an accurate prediction about the future. Economists and political scientists cannot do this accurately. Thus everyone thought Hillary would win. Everyone thought Obamacare would have enrollments twice as high as it does and at half the cost. So... when we say \"does socialism work?\" we can't look to theory and use that theory to predict the future because economics and politics can't do that. What we can do is look to real world examples and ask \"did it work there?\" And the answer to that question is always no. Some european countries flirt with some socialist theories, but they are not really socialist. The socialists are the Cubas, the Venezuella's, the Soviet Unions, the Vietnams, the North Koreas. And they just, simply, do not work. America has a more hard nosed view of this than Europe because many European countries have flavored their cup of capitalism with a drizzle of socialism and had a good result. So its natural for you to ask \"what if we add more socialism, or go full socialism\". America has had a good experience with its cup of capitalism and would like a second if at all possible."], "text_urls": [[], []], "score": [4, 3]}}, {"q_id": "5oyjai", "category": "Repost", "title": "How does a sailboat get to a westward destination if the wind is out of the west?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dcn136d", "dcn140a"], "text": ["You don't sail in a straight line, you sail at an angle so the sails can catch the wind, then turn and go the other way, in a zigzag pattern. It's called \"tacking\".", "A boat can only sail in 270/360 degrees of possible travel. So if you imagine a clock face on the water with noon point at the direction of travel from 10 to 2 is called irons or the no-go zone. This is where the wind is coming from and the sailboat can't sail. In order to travel in this direction, the boat has to tack (turn) back and forth and zig zag up the lake/river/ocean. *So in your example the boat would probably travel northwest and then tack to head south-west and then northwest again zig zagging so that the north/south travel is canceled out and then westward travel remains edit*"], "text_urls": [[], []], "score": [11, 3]}}, {"q_id": "5p2r7n", "category": "Repost", "title": "Why do colossal creatures appear to move so slowly?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dcnz33c"], "text": ["Ask yourself this: are they really moving slowly? Say a humanoid creature ten times the size of a normal human is capable of swinging its fist just as fast as a normal human can. Well, the speed's the same, but since the creature is so large, there's much more distance to cover, so it takes more time to complete actions that would take a normal-sized creature less time, even if the two different-sized creatures move their limbs, or whatever, at the same exact speed. Your next question might be, why wouldn't the giant creature move faster since it's so much stronger? Well sure, the giant has more muscle so it can apply greater forces, but its size means it also has a lot of mass to deal with as well. This could probably be explained better, but if you take Newton's Second Law: F (force) = m (mass) x a (acceleration) and rearrange it to read a = F / m then you increase both the force AND the mass to represent our giant's increased musculature but also its greater size, you find that if F and m are increased at around the same rate, the resulting acceleration stays about the same. So since more muscles means more mass to move, and more size means more distance to travel, you end up with big lumbering giants like in the movies. It just makes more sense."], "text_urls": [[]], "score": [4]}}, {"q_id": "5p79tt", "category": "Repost", "title": "What is a Denial of Service (DoS) attack.", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dcoy9xe"], "text": ["As some internet smartass once put it \"Wanna DDoS a bar? Get a shitload of friends to all go in and keep asking for glasses of water.\" The point of a distributed denial of service attack is to tie up one server with **so many** requests that ultimately aren't real that it has no time to service the actual users who want to visit the page. All web traffic starts with *some* form of request and conversation between the two computers. The attacking computers in a DoS scenario just drop the conversation and start over from the top every few seconds. Usually to pull off a DoS attack effectively, you need a botnet, a network of thousands of virus'd computers that accept commands you give them. If you tried to pull a DoS attack with just one or relatively few computers, it would be very easy to trace and blacklist you. But if thousands of computers all over the world all connect to your victim's server simulatenously, that server can't tell which incoming requests might belong to real users and which are bogus and going to end early."], "text_urls": [[]], "score": [6]}}, {"q_id": "5p8fg4", "category": "Repost", "title": "How are devices like cellphones and laptops still able to keep track of time even after their batteries are removed but my clocks need to be reset every time the power goes out?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dcp87yd"], "text": ["Cellphones are a bad example because they'll synchronize their time with cell towers as soon as they get powered up again. Laptops have another battery explicitly for keeping the clock going and ensuring low level settings are preserved, just like desktop PCs."], "text_urls": [[]], "score": [6]}}, {"q_id": "5p8zk9", "category": "Repost", "title": "Why can you sometimes \"feel\" someone watching you?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dcpdx6b", "dcpdkxv", "dcpe5pq", "dcpiidr"], "text": ["When you turn to look at someone they can notice the motion of you turning and look at you, so it appears to you they have been staring at you. The rest is probably just confirmation bias. A study in 1913 where the test subjects could not see the person staring reported 50.2% correct guesses, indicating that there is no basis to whether someone is looking at you. URL_0", "There is no reason to think that a human can. My guess as to why this myth persists would be a combination of good old fashioned confirmation bias. As well the fact the **you** turning your head gets the attention of the person you *thought* was looking at you causing them to look at you. So you see them looking at you & assume you were right.", "Your brain has evolved to keep you alive in the wild against literal lions, tigers and bears. It also helps you see prey and is geared for social interactions. You literally have brain circuits to notice when you see eyes. Even if you don't consciously notice it the feeling is there. Is it a deer in the trees? A large predator? Grognak the barbarian to ambush you? You don't know but the circuits activate and you feel on edge.", "Most people say its not real since there has been no scientifically supported and reproduced proof of any cause or even the feeling itself. However, and this is heading into anecdotal territory, I know a number of veterans and many have told me about how their escape and evasion trainers taught them to never look directly at the person you're hiding from. Instead watch them in your peripheral vision. I do casual experiments with this technique often and to be honest it definitely seems to work. Explanations given were varied including the most convincing and succinct: \"You can camouflage your whole body 'cept the whites of your eyes so don't show em.\""], "text_urls": [["http://www.jstor.org/stable/1413454"], [], [], []], "score": [90, 27, 14, 11]}}, {"q_id": "5p945b", "category": "Repost", "title": "Why do SCUBA divers go into the water backwards instead of front first?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dcpek8o", "dcpjxge", "dcpe3v7", "dcpe6fu", "dcpp6wt", "dcpjuyi", "dcpevzr", "dcpmkiu", "dcpqicm"], "text": ["If they don't go back first, they go feet first. Both for several reasons. 1. Out of the water, the tank is **heavy**. Imagine doing a belly flop while wearing a backpack full of cinder blocks. You hit the water, then the pack hits you. Ouch. 2. Hitting the water face first means you get the mask smacked into your face. Ouch again. 3. Some kinds of SCUBA gear will have bits extending behind your head. Going face first means you have a good chance of smacking the back of your head on them. Not fun. 4. When you hit the water, you are less concerned about landing on the guy that is already in the water than you are about the next guy in line landing on *you*. Going back first means you can see what's going on above you and move if needed. 5. Lastly, sometimes shit happens and you need to quickly ditch your gear. If you are face down, you have to get out from under the stuff after you undo the buckles, risking getting something getting caught in a stray loop. Face up means everything is below you, thus much less risk of getting snagged.", "In the PNW we very rarely use the seated back roll entry technique unless entering the water from a boat like a zodiac or similar. Usually we use a giant stride entry when entering from boats or docks. But the reason for the seated back roll is because when you're diving you have a lot of heavy and loose gear, and you want to be in control of it all and yourself the whole time. The seated back roll (SBR from now on) is really good for wrangling your hoses and accessories in front of you where it can all be held onto while at the same time holding the clasp of your weight belt. It also allows you to lead with the hardest heaviest and least fragile part of your body and gear: the tank. If say, a log floated up next to the boat while you were managing all your gear and getting ready to take a dip, and you didn't see it, when you roll backwards, your tank shields you from the blow of hitting the log from a small height with sometimes nearly 100 lbs of gear on top of you. It also serves to propeller you away from the boat quickly and with little effort. This way, you clear the boat, which may be bobbing up and down on rough seas, as well as allow someone else to enter behind you. It also serves to, usually, orient you facing the boat when you surface so you can signal the boat that you're OK and do not need assistance. Also, if the seas are you specially rough, your tank breaks the water for you so you don't get smacked in the face with an upswell right as the boat breaks the crest of the previous wave and you fall face first into it (no fun). Tl;Dr - it's easier and safer than the alternatives sometimes. Source - am PADI Divemaster, out of teaching status Master SCUBA Diver Trainer. Yes, I know, we have the best \"ranks/titles\"", "In short, divers have two main ways to \u2018jump in\u2019 from a scuba dive boat: The Giant Stride Entry (requires a stable platform from where to step off; common in larger boats) The Backward Roll Entry (preferred technique when the boat is smaller, less steady, and lacks a secure platform or ladder) Plus, think about this: walking around in fins is difficult and you're carrying the weight of a scuba tank (not light)- it's easier to roll backwards off the boat than to walk to the edge and stride off.", "One method is to take a step off the boat into the water - this works well when your boat has a platform that you can step straight off of into the water. If you're trying to enter the water over a gunwale going forwards, your flippers will get in the way, making it difficult to smoothly enter the water. Instead, divers sit on the gunwale, which allows them to smoothly lean back into the water, rather than making an awkward forward step over the gunwale. Sitting on the gunwhale also helps ensure you won't hit your tank or head against anything as you enter the water.", "Simple explanation for a five year old: Because it's easier to sit on the side of the boat and fall backward into the water than it is to lift your feet with fins, stand on the narrow side wall of the boat, balance yourself for a second without falling back into the boat, and then jump forward into the water.", "I understand what you meant, in fact most people did but divers can be dicks... So we have two different kinds of entries when diving. The first is called a 'giant stride entry' which is what is says on the tin. You take a big stride into the water. This is typically off of the back of a big hard boat or from a shore entry with a drop below. Don't hop in because you're likely to hit your cylinder on the entry point and knock yourself clean out (I've dragged a couple of people out who have done this.) The second, which is the one you're on about, [is typically out of a rigid hulled inflatable boat (RHIB.)]( URL_0 ) The reason we roll off backwards is because the boat will rock like crazy if you try to stand up in heavy dive gear. It's pretty low in the water and you're also less like to knock any gear off as you enter. Everyone needs to go at the same time or you risk clocking someone in the face with your cylinder. The super fun entries are negative entries using RHIBs off of big boats in strong currents - you roll into the water as a group with no air in your jacket and head straight down. Feels like being a navy seal.", "When walking from shore, it's easier to walk backwards with fins on. When sitting in a small boat you usually face inward while underway, and it's easier to just fall backwards over the side than to turn yourself around. Perhaps another reason is that hitting the water face first could dislodge your mask or regulator.", "Actually most SCUBA divers dont usually enter the water backwards, and ill get to that in a second. But first the answer to your question. I assume that the entry technique you are referring to is when the diver rolls backwards of the side of a smaller boat. In that case it is because when geared up you are crazy top heavy, and most people are not super graceful on land when in full gear. Couple that with a small and rolling boat, and you must be able to put your gear on and drop in to the water without standing up. It also minimizes the risk of people dropping in on top of each other, as divers will each drop from a different spot on the boat, and once they hit the water they can see the boat and get out of the way of the next diver. As a side note doing \"negative\" (non floaty) entries from small boats in rough waters makes you feel really cool. However there are many other entry techniques which are also very common. In a lot of places people dont dive of boats in the first place, and when shore diving you would just walk out into the water, or do a \"giant stride\" if there is a dock or something. A giant stride is common from bigger boats and is just a fancy word for stepping of the boat forwards. Of course there are tons of ways to get in to the water, and a part of being a good diver is to choose an appropriate one for the situation. When diving of my familys sail boat for example I usually make my gear buoyant and throw it down first before going in after it, since the entry is quite high and there is not much room up on the back. A favourite entry of mine as an alternative to a giant step, is to do three quarters of a flip forwards and land on the tank (on my back). But that is only with people I know, it looks kind of uncontrolled and is not a favourite with DMs and boat crew, its good fun tough.", "We only do that on boats where it's not practical to jump into water feet first, like on inflatable boats. Space in these boats is scarce and the two big tubes on the sides are hard to step over (especially with fins, in a thick suit, and with 25kg of gear on our backs). Standing on the tubes is dangerous as they are slippery, unstable and not flat , so it's easier (safer) to sit on them and fall backwards. Generally speaking, in an inflatable you avoid standing up when you have your gear on anyway. With any boat that has a big platform in the back, it's much easier to jump feet first."], "text_urls": [[], [], [], [], [], ["http://www.maritimejournal.com/__data/assets/image/0021/514083/MJNOV13DU-Zodiac.jpg"], [], [], []], "score": [7552, 1585, 295, 18, 17, 13, 7, 5, 3]}}, {"q_id": "5p9u02", "category": "Repost", "title": "If some letters are silent in certain words then why include then at all?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dcpj342"], "text": ["Often just tradition. When they began printing books in English, there weren't many typesetters in England, so they imported Dutch typesetters who often spelled English words in a Dutch way. So that's how we got the 'h' in 'ghost' and 'ghastly.' Other times the silent letter actually serves a purpose. The difference between 'can' and 'cane' is the silent letter 'e.' That 'e' lets the reader know that they should pronounce the 'a' as a long vowel. Edit: [A much more eloquent source]( URL_0 )"], "text_urls": [["http://www.bbc.com/culture/story/20150605-your-language-is-sinful"]], "score": [4]}}, {"q_id": "5pahgk", "category": "Repost", "title": "How exactly is data transferred wirelessly? Bluetooth, Radio, Satellite, NFC, Wi-Fi, Li-Fi etc?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dcpo0ue", "dcq7iqo", "dcpp8wv"], "text": ["Imagine the hose in your garden. Its connected to a faucet. If you open and close it fast enough and in a pattern, water comes out of the other end also in a pattern. Now, devices have recievers and transmitters. These know how to \"read\" and \"write\" patterns respectively. We can now set this up so that certain patterns can mean certain symbols. A collection of symbols can ultimately form an email, a message on facebook, and more complex streams like pictures and videos. in real life, these devices turn on and off at tremendous speeds, and as a general rule, the faster you can turn on and off, the more information you can send in a single time frame.", "Imagine that you have a light that you can switch on and off rapidly. You could use this light to send messages to other people. Not just simple yes/no signaling, but actual textual messages by using a code like Morse Code. Now, computers don't use Morse code, they use other various things, but the analogy holds. If you speed up the pulsing on and off of the light to something way faster than your eye could perceive, but not so fast that it couldn't be picked out mechanically (this doesn't take much, by the way), you could have a computer looking at that light and reading the messages out of it. That's Li-Fi, which is the easiest of these to understand. Now, let's take it a step further. Let's say you made that light a single color on the spectrum. Let's start with green, since that's roughly at the middle of the visible spectrum. Green light, like all light, is made up of electromagnetic waves, and these have a *frequency* that defines the color. The frequency is the number of these electromagnetic waves that arrive in a second. For green light, that frequency is somewhere around 6,000,000,000,000,000 time per second, or 6 petahertz (PHz). If you made the light blue instead, it would be more like 7.5 PHz; red would be closer to 4.2 PHz. The human eye can perceive electromagnetic waves from roughly 4.2 PHz to 7.7 PHz. A little faster than this, and you get ultraviolet light, which is what give you a suntan or sunburn, but you can't see it; A little slower and you get infrared light, which, when you go far enough slower, you will feel as heat. What happens if you go even lower? When you go down below 300,000,000,000 waves per second, or 300 GHz, you are starting to enter the realm of radio waves. In particular, radio waves from about 400-600 MHz up through 300 GHz are called \"microwaves\", and these are used for Bluetooth (around 2.4 GHz), Wi-Fi (around 2.4 GHz and 5 GHz) and sometimes for other things. For satellite, whether it be radio, television, data or phone, the same process is involved. However, in this case, there is a relay station in orbit around the planet. A parabolic reflector (i.e. a dish) is used to focus the radio waves on the satellite so that they can travel the long distance. The satellite receives the radio waves, and then sends the same message back down on another frequency. A similar reflector is used to focus the incoming beam to make it strong enough to decode. For radio, it's much simpler. Radio doesn't use microwaves, but lower frequencies. FM ranges from 88,000,000 wavefronts per second to 108,000,000 wavefronts per second, or 88-108 MHz, and these are the numbers you see on your radio dial. AM goes even lower, running from 530,000 to 1,710,000, or 530-1710 kHz, again, the numbers you see on the radio dial. For FM radio, the \"color\" of the radio wave (its frequency) is varied up and down, so a radio station on, say, 99.5, may actually be on 99.425 to 99.575 at any given moment, this change in the frequency being what carries the information. This is called Frequency Modulation, and is what FM stands for. For AM radio, the \"brightness\" of the radio wave (its amplitude) is varied from off to double some central value, and this change in ampiltude is what carries the information. This is called Amplitude Modulation, and is what AM stands for. I can talk a little more about digital things like WiFi or Bluetooth, but it would no longer be ELI5.", "Wireless technologies will generally use electromagnetic radiation to communicate. Well known examples of electromagnetic radiation are radio waves and visible light. We can see light, but other forms of radiation are generally not easy to detect with human senses. In a way vaguely similar to how it's possible for you to communicate without wires at a distance by flashing a torch (say, by using Morse code), you can use OTHER types of electromagnetic radiation to transmit signals between devices - so long as the devices are equipped with the right sensors and are close enough to see signals (in our morse torch example, this is just being close enough to see the torch, and having eyes to see the flashing - in technology, this is being within broadcast range and having the right receivers)"], "text_urls": [[], [], []], "score": [46, 12, 5]}}, {"q_id": "5paiy8", "category": "Repost", "title": "Why all the countries can't have the same currency? It would be possible in the future?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dcpnjsd", "dcpnft9"], "text": ["This would require surrendering their monetary sovereignty. Governments don't like other people having control over the figurative printing press, and would loathe to give this up to a supranational body. Furthermore, this would likely require the establishment of a global central bank, which would conduct the other end of monetary policy; the conflicting interests of member states coming into conflict can be clearly seen in the case of the European Central Bank. Basically, you need *every nation in the world* to work together. So, unless someone takes over the world and crushes all the other nation-states, it's not happening.", "The reason the Euro is having so much trouble is all countries currency has the same value but they all have different economic policies that generate different economic worths."], "text_urls": [[], []], "score": [5, 3]}}, {"q_id": "5pfdog", "category": "Repost", "title": "what are muscle knots?", "title_urls": {"url": []}, "selftext": "I was getting a back rub yesterday and my wife found a knot in my back that kept \"clicking\" when she would pass over it. What is it and what is the best way to get rid of them?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dcqta2u", "dcqsm4d"], "text": ["Muscle 'knots' or trigger points are a frequent discussion topic among health professionals and no one can really agree on what they are. There are a lot of conflicting opinions etc out there but we do know that muscle releasing techniques (massage/dry needling/acupuncture/foam rolling or using a spikey ball) can help alleviate any pain related to them. As for the clicking, that can be caused by rolling tendons or bands of muscle across each other or over a boney point/surface. It's normal for these to feel a bit sore when applying pressure to them so no need to be concerned or anything. Stretching and the other aforementioned methods are great for treating these 'knots'. However please don't try to dry needle or acupuncture yourself. That would be silly.", "A swollen, torn, or tense muscle. I get them in my back and neck.. I press on the knots for a couple seconds, gets me kind of dizzy, then I massage it and take an ibuprofen to relax it."], "text_urls": [[], []], "score": [12, 6]}}, {"q_id": "5ph37b", "category": "Repost", "title": "What is a pyramid scheme and why is it bad?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dcr4gjx"], "text": ["The guy at the top starts and recruits 6 people to sell his product. He gets all of their sales and the only way they can make money is to recruit 6 more each. The same thing for those people. Only problem is, after the 7th or 8th generation, the number of people involved becomes greater than the global population. Big problem, right? So those at the very top get incredibly rich while those at the bottom get screwed."], "text_urls": [[]], "score": [4]}}, {"q_id": "5pj0if", "category": "Repost", "title": "What do massive, widespread protests actually accomplish?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dcrims4"], "text": ["A range of things, sometimes all of them, sometimes none: - Raise awareness for an issue or group - Tell governments (or other protestees) that many members of the public are not OK with their actions - Show decision makers that a certain action is desired by many members of the public - \"Threaten\" decision makers that your group cam mobilize many people (this is relevant, say, in trade union-employer talks, where trade unions try to proof they can mobilize the workforce for a strike with a smaller, shorter protest first to strenghen their position)\u00a8 - Give protesters hope, show that they are not alone - Serve as a way to organize more people - by showing that you can organzie a big protest, others are more likely to join your cause or group"], "text_urls": [[]], "score": [7]}}, {"q_id": "5pjuca", "category": "Repost", "title": "Why is it when you speed up a voice it becomes higher pitched?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dcroeew", "dcroh51"], "text": ["Another word for 'pitch' is 'frequency', which is measured in Hertz (Hz), or cycles per second. If you speed up music, it goes through the same number of cycles in a shorter time, therefore more cycles per second, therefore a higher frequency. Music is made up of many frequencies played simultaneously, but all of them are affected in the same way when sped up. Taken from [this]( URL_0 ) and /u/lithiumdeuteride", "It's to do with the frequency. If you picture sounds as a wave. A higher pitched sound vibrates more than a slower sound. Therefore speeding up a sound causes it to vibrate more quickly, changing the pitch. The same is also true in reverse. If you slow a sound down, it vibrates less and lowers the pitch"], "text_urls": [["https://www.reddit.com/r/askscience/comments/1d9b6f/why_does_sped_up_music_sound_higher_pitched/"], []], "score": [19, 4]}}, {"q_id": "5plqoe", "category": "Repost", "title": "So what powers does the Queen of England actually have? Does she really have authority to do anything?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dcs5cqd", "dcsl6ow"], "text": ["The Queen holds the power to deny assent. This is the equivalent of the POTUS veto power. She has only ever used it at the request of the Prime Minister, but she does technically have the power to use it on her own. The Queen also technically has the power to force a new election of Parliament if she feels it is corrupted. This power was used in the 1970s in Australia to force a re-election by her proxy in Australia. This power has also been heavily limited in laws passed in 2011 by Parliament. The Queen is the Commander in Chief of all her armed forces. So the UK military and every military division held by the Commonwealth nations that has \"Royal\" in the title are under her command. She has never (or at least rarely) ever issued a direct command and instead relies on Generals that act as her proxy but she has the power to command the troop in the same way that the POTUS has the power to command US troops. And like the US she cannot declare war, that is done by Parliament for the UK like it is with Congress for the US. She and Royal family also act as the top level ambassadors, and approve the appointment of all ambassadors. This is a function like what the US President does.", "/u/cdb03b has answered the question well, so I'll just add something separately. The Queen has many titles and roles, but none of these include the \"Queen of England\" as England isn't a Kingdom on its own. That stopped back in 1707 when the thrones of England and Scotland were united to create the British throne. It's like calling Trump the President of California or something - it's just a bit of a larger country that they're in charge of. In this context you would call her the Queen of the United Kingdom, or UK for short. She's also the Queen of 15 other nations, and these are collectively known as the Commonwealth Realms."], "text_urls": [[], []], "score": [58, 4]}}, {"q_id": "5pp1ls", "category": "Repost", "title": "Why do we have eyebrows?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dcspddm"], "text": ["Sweat catching may have been the original reason, but it's also been shown that people are able to read facial expressions based on eyebrows far easier than just eyes alone."], "text_urls": [[]], "score": [3]}}, {"q_id": "5pp5yp", "category": "Repost", "title": "How do those 'I'm not a robot' captchas work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dcspqfx"], "text": ["Most people think those captchas are tricking the machine into not knowing where to click because it's an image, but that's not the case most of the time. When those captchas are being done, there's a multitude of things being taken into consideration, such as how long you take to move the mouse between boxes, if your mouse moves directly to the box, or a little more sporadically. It's much easier to program something to be extremely slick, direct, and careful. It's hard to program something that actually behaves like a human by not being incredibly perfect. Things like that alert the system that the \"user\" is likely just a program trying to hack into it, and it then stops access."], "text_urls": [[]], "score": [3]}}, {"q_id": "5ppmcr", "category": "Repost", "title": "How is Universal Basic Income supposed to redistribute wealth?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dcst3vg", "dcstfgz", "dcszgui"], "text": ["The simplified version is that while everyone would get some money, it would mostly be the wealthy *paying* it. Universal income requires an increase in taxes to cover it, and the idea is to have those increased taxes mostly fall on the wealthy. Say you have someone earning $10 million per year in income. Right now they pay ~40% income tax, or around $4 million per year, so they take home ~$6 million. For universal income to work, they would need to increase that person's taxes, say to 50% or $5 million per year. Now the government is getting an extra $1 million per year from that person. If the universal income is $20,000/year, that means that one person is now funding the basic income for 50 people (well, 49, since he gets a piece too).", "Because it would phase out as one earns income from jobs, the effect would mostly be to replace funds coming from a number of different aid programs into one. Instead of collecting welfare or unemployment, housing vouchers, food stamps, school lunches, medicaid, etc. it would just provide a single sum of money to set a baseline for living on. There would be some incentive to work and keep income from a low wage job plus UBI, or at least much of it, but the types of things somebody just coming out of poverty would buy with additional income are not supply constrained to the point of causing inflation as a result.", "It's not meant to redistribute wealth, it's meant to keep labor from starving to death when they are replaced with automation."], "text_urls": [[], [], []], "score": [12, 8, 3]}}, {"q_id": "5ps32a", "category": "Repost", "title": "What's the whole deal with Flint, MI?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dctdh8k", "dctddvg"], "text": ["So, the pipes were made of lead and lined with something else to keep the water safe. Then they changed sources and the lining got stripped, leeching lead into the water. People won't fix it because literally the entire city, everyone's houses, and the pipes leading out of the city would need to be dug up and replaced.", "The powers is group of people. They can't just wave the magic wand and everything is all dandy. They're in process of replacing a million miles of underground pipes. Digging up the ground and laying new pipe costs money and time. And nobody is willing to pay the overtime for it."], "text_urls": [[], []], "score": [5, 3]}}, {"q_id": "5psffh", "category": "Repost", "title": "What are the differences between socialism and communism?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dctic9v"], "text": ["These terms have been used in many different ways by many different people, and often if you say \"socialism\" you're going to mean something fundamentally different than what the person you're talking to thinks you mean. With that said, at least in classic Marxist theory, the difference is commonly summed up by a couple phrases: \"Socialism\": \"From each according to his ability, to each according to his contribution\". \"Communism\": \"From each according to his ability, to each according to his need\". Before continuing, a couple things should be noted here: (1) Marx viewed \"socialism\" as being a stepping stone leading from \"capitalism\" to \"communism\". (2) By \"capitalism\", he didn't really mean exactly what you might think of when you hear that term today; think more like \"robber baron\". The small ownership class just flat out exploits the masses of the laborer class, with little to no governmental regulation, and little to no hope of economic mobility between the classes. In the remainder of this post, I will be using \"capitalism\" to mean something like what Marx meant by it, not what we mean by it today. So, in classical Marxist theory, capitalism eventually collapses, because \"Jesus Christ fuck that shit\", say the huge masses of exploited laborers. This leads to socialism, wherein the state takes over ownership of the means of production (factories and whatnot), and the benefits of labor are distributed in a more egalitarian fashion (as opposed to the \"owners profit and laborers subsist\" of capitalism). But there are still economic classes, because \"to each according to his contribution\". So, you get more if you're more skilled, or you are more productive, or whatever. Eventually the economy is really up and running on all \"from each according to his ability\" cylinders. This makes the economy much more productive than under capitalism, for multiple reasons. For example, there's no longer the useless leeching of the ownership class. Another example, many truly productive people whose abilities would have been squandered by capitalism (due to just being considered things to be exploited, chewed up, used up, and thrown away) are now prospering in roles that suit them better, which leads to better production all around. So now the economy is really, really productive. It's so productive it's creating a massive surplus. The surplus is so vast that there's really no need anymore for economic classes - if someone needs something, society can provide, regardless of whether that person is some sort of production superstar or less so. So, \"to each according to his need\", and we've now arrived at communism."], "text_urls": [[]], "score": [3]}}, {"q_id": "5pwho5", "category": "Repost", "title": "Why can't bots check the \"I am not a robot\" captcha?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dcuc33n", "dcuc3ye", "dcuhat1", "dcuc3c3"], "text": ["The checkbox is not the real test. Checking a box is easy. What it does it is reada your mouse movement while you're on the page, and since you move the mouse in an organic, imperfect way it decides you are not a script or \"bot\".", "[From May 2016: ]( URL_0 ) Google is keeping its algorithms secret so all we can really do is make guesses about how it works, but my understanding is that the new system will analyze your activity across all of Google's services (and possibly other sites that Google has some control over, such as websites that have Google ads). Thus, it is likely that the checks are not limited to just the page that has the checkbox on it. For example, if they detect that your computer/IP address you are using was also used in the past to do things that a normal human would do - things like checking Gmail, searching on Google search, uploading files to Drive, sharing photos, browsing the web etc. - then it can probably be reasonably sure that you are a human and allow you to skip the image verification. On the other hand, if it can't associate your computer with any previous human-like activity, then it would be more suspicious and give you the image verification. Though the mouse behavior as it clicks the checkbox may be one factor it analyzes, there is almost certainly a lot more to it.", "You are definitely [not the first person to ask this question 'round here]( URL_0 ). tl;dr it's not just the click.", "The way a human moves the mouse before checking the checkbox can be distinct from how a program (a bot) checks a checkbox. It's a game of prediction. Somehow, Google needs to predict whether you are human or a bot from what you do on their site. So first a system needs to be trained to predict whether the user is human or not. For this you need training data (which Google has plenty). That data includes sample movements of mouse made by humans as well as robots (programs). Using this training data, a predictive model is made. So when you move your mouse to check the checkbox. That movement is an input to the model and based on that it's predicted whether you are human or not. If you are then fine, otherwise the same old method of filtering humans through a distorted image is used."], "text_urls": [[], ["https://www.reddit.com/r/explainlikeimfive/comments/4j5t1z/eli5_how_does_googles_no_captcha_recaptcha_work/"], ["https://www.reddit.com/r/explainlikeimfive/search?q=i+am+not+a+robot&amp;restrict_sr=on&amp;sort=relevance&amp;t=all"], []], "score": [18, 5, 3, 3]}}, {"q_id": "5pxfka", "category": "Repost", "title": "Why is it that when we chew mint gum, everything we drink is super cold?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dcuk50d"], "text": ["Minty flavoring works by activating the cold sensors in your mouth. It basically tricks your mouth into thinking everything got colder, and you get the minty feeling. And naturally, when you drink something that actually IS colder than your mouth, the feeling is magnified. EDIT: small correction"], "text_urls": [[]], "score": [20]}}, {"q_id": "5pyx56", "category": "Repost", "title": "Why can't fighter jets reach outer space just like normal spaceships do?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dcux26j", "dcuxcu4"], "text": ["Spaceships carry both fuel and oxidizer with them, whereas jets carry fuel only and use the atmosphere to provide the oxidizer. As the jets fly higher up, the atmosphere get's thinner, meaning there is less oxygen available for combustion, which is how you push the plane or the rocket in the first place. In addition, with the thinner atmosphere, it's harder to generate lift through aerodynamic forces, which makes it rather difficult to fly.", "Jets move forward by sucking in air and then pushing it back out at high speed. The less air there is, the less thrust they can get. Air-breathing systems become very inefficient well before they would reach the official boundary of space (100 km) because of how little air there is at high altitudes. A rocket is different because what it shoots out the back to accelerate is gases created by on-board fuel and oxidizer rather than sucking in outside gases, so it can keep accelerating even as the outside air thins to vacuum."], "text_urls": [[], []], "score": [13, 7]}}, {"q_id": "5pz24t", "category": "Repost", "title": "Why are men's nipples perfectly acceptable to show on Tv, social medias etc, but not women's nipples and breast?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dcuyftr", "dcuzvte"], "text": ["Men find these parts of women highly sexually attractive. Consider the existence on this very website of /r/boobies and /r/boobs and /r/boobbounce and /r/Nipples and and /r/nipslip and /r/BreastsInTheirPrime and many, many more subreddits whose only purpose is staring at pictures of breasts and nipples. The reverse is not equally true. The sight of male nipples is not, for the average woman (or man), a huge source of sexual arousal.", "Also, mens nipples can be used for arousal and I'm sure there is some kind of fetish for them. Might as well cage all nipples. While were at it, a ban on showing feet since the dirty minds of humans find a fancy for those."], "text_urls": [[], []], "score": [11, 3]}}, {"q_id": "5q0tzf", "category": "Repost", "title": "How can we move freely in a car when it's going at high speeds?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dcve7yz", "dcvdyws", "dcve469", "dcveiqc"], "text": ["Because you are moving *with* the vehicle. The key here is relative speeds -- your speed relative to the interior of the vehicle is 0. You *and* the car are both traveling at 60 mph, or whatever. This isn't the case, however, when the car is accelerating. This is why you feel pressed against the back of the seat, or against the seat belt when the car brakes. This is why seat belts are so important -- in the event of the crash, the car itself, being made of metal, decelerates rapidly. You, however, do not, until you hit something hard. Like the dash.", "what force is it that you thing would prevent you from moving?", "If the car goes at a constant speed, it has no impact on your movements, it's physics. What makes you move forward or backward in a vehicle is the acceleration (or the deceleration).", "The same reason why you can move freely and walk down the street. Earth also moves at very high speeds, multiple times more than a moving car. But when the Earth or a car moves, you also move with it, thus having the same velocity. Say a bus travels at 60km/hr, and you are walking at a rate of 5km/hr. When you walk inside a bus, you are actually moving at 65km/hr relative to the Earth, thus making you 5km/hr faster than the bus. Which gives you the \"being able to move freely\" sensation."], "text_urls": [[], [], [], []], "score": [7, 5, 3, 3]}}, {"q_id": "5q15mp", "category": "Repost", "title": "Aside from signing executive orders, what power does the president actually have to force Mexico to pay for a border wall?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dcvhblf"], "text": ["Theoretically you can threaten tarrifs on their goods if they don't pay and offer them trade deals if they do. That's about the only real power short of war. If they don't pay either we build it and pay for it or we don't build it."], "text_urls": [[]], "score": [3]}}, {"q_id": "5q1hla", "category": "Repost", "title": "Why do we suddenly jerk when we're about to fall asleep?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dcvk90e", "dcvk0wr"], "text": ["It's called a hypnic jerk. It's believed to be your nerves misfiring when you transition to sleep. Some say they are worse when you are stressed or have anxiety. I get them severely.", "Its called a myclonic jerk. In essence, your brain sometimes thinks a rapid loss of consciousness might be death or shock, rather than sleep, so it sends and impulse through your body in order to verify a response and make sure you're still alive."], "text_urls": [[], []], "score": [9, 6]}}, {"q_id": "5q3na3", "category": "Repost", "title": "How does Full Disk Encryption (in particular Bitlocker) work?", "title_urls": {"url": []}, "selftext": "So is the whole drive encrypted from start to finish with a specific password or keyword? Is this why the 'recovery key' is fairly long and unique? I understand my Windows password forces the TPM chip to automatically unlock the drive, but who creates the actual algorithm? What happens if one block of the data becomes corrupt? Does it not corrupt the entire drive? Are the files encrypted/decrypted individually on the fly, and if so, why does it not slow performance. Can a virus still infect the HDD if it's not mounted (could someone boot from an infected USB drive) or is the drive entirely locked without the key.", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dcw05l4"], "text": ["A boot sequence executes during the startup process of Microsoft\u00ae Windows, Apple Mac OS X, or Linux\u00ae operating systems. The boot system is the initial set of operations that the computer performs when it is switched on. A boot loader (or a bootstrap loader) is a short computer program that loads the main operating system for the computer. The boot loader first looks at a boot record or partition table, which is the logical area \u201czero\u201d (or starting point) of the disk drive. Whole disk encryption modifies the zero point area of the drive. A computer protected with Whole Disk Encryption presents a modified \u201cpre-boot\u201d environment to the user. This modified pre-boot screen prompts a user for authentication credentials in the form of a passphrase (a long password that is like a sentence). At this point, the computer may ask for additional credentials such as a smart card or token. After the user enters valid authentication credentials, the operating system continues to load and the user can use the computer. Whole Disk Encryption software also provides the ability to encrypt removable storage media such as USB drives. When you insert an encrypted USB drive into a computer system, it prompts for passphrase, and upon successful authentication, you can use the USB drive."], "text_urls": [[]], "score": [4]}}, {"q_id": "5q3odv", "category": "Repost", "title": "why are people harder to pick up as \"dead weight\" as opposed to when they're letting you lift them? they don't really change weight", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dcw0edo", "dcw1boj", "dcw0agq", "dcwi26y", "dcx3dwi", "dcxcc1s"], "text": ["They don't change weight, but they do shift and support their weight to make it easier for you to grab and maintain balance. That's also why a 45 pound block of wood is easy to lift but a 45 pound bag of water is a nightmare. You can't grab or balance the water and its center of gravity is constantly shifting as you fumble with it.", "It's not weight but weight distribution. People tend to orient themselves for maximum comfort which helps keep weight balanced and easier to carry. Try lifting at the gym without locking the plates in. Same weight but it requires good balance and technique in addition to strength. So it's harder. It's why you center a bag on your shoulder or evenly space dishes on a tray.", "If they're awake, chances are they're grabbing your neck/shoulders and pulling themselves up at the same time that you're lifting them. This distributes their weight somewhat more evenly through your torso, making them feel lighter.", "Balance. Picking up a cone horizontaly by the small end is harder than picking up by the large end. That proves that balanced objects are easier to lift and handle. Alive people don't like to fall and have a sense of equilibrium that helps them balance their weight whe you're carrying them. Dead people don't do this.", "Dancers know about this well. It doesn't matter how big the girl is, if she doesn't \"hold herself\" then it's like trying to lift a sack of potatoes above your head. A girl at my dance college was broad and nearly 6ft. When we started partner lifts, she wanted to skip class because she was \"too big\" She had a solid core and was the easiest to lift and partner.", "Also, a conscious human body acts more like a single solid object, where as an unconscious body (or one that's deliberately limp) is more like a collection of huge sausages tied together, which is much harder to lift and carry. Which is saying the same thing as everyone else, just in a different way. When our daughter was little enough to carry you could really feel the difference between when she was making an effort to balance/hold herself together and when she wasn't, usually if she was tired. She absolutely felt heavier, it was amazing. We used to say her antigravity wasn't working."], "text_urls": [[], [], [], [], [], []], "score": [129, 13, 6, 6, 3, 3]}}, {"q_id": "5q5m21", "category": "Repost", "title": "How does the sun give us vitamin D?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dcwh821", "dcwk2a1", "dcwh5lx"], "text": ["It doesn't, people just say it does as a shorthand way of talking about it. Your body naturally produces it... most of the way. But it takes ultraviolet light to trigger the last chemical reaction that makes it biologically viable to the body.", "Vitamin D isn't actually a single chemical, but a compound material. In fact, it's not even technically a vitamin, becuase it's produced in the human body and it is absent from nearly all natural foods (save egg yolks and some fish), and even when it's obtained from those foods it must be transformed by the body before it can do any good. As our habits have changed through the years, most of us can no long rely on vitamin D produces the old fashioned way, by our bodies. Instead, we increasingly depend on supplements and artificially fortified foods, like milk. Sunlight is the key to utilizing vitamin D. The natural type is produced in the skin from a universally present form of cholesterol, 7-dehydrocholesterol. Ultraviolet B (UVB) energy converts the precursor to vitamin D3. Dietary supplements are manufactured by exposing plant sterols to UVB, producing vitamin D2. Because their function is almost identical, both types are lumped under the heading vitamin D. Most importantly, neither of them will function until the body works its magic. The suns energy converts the 7-dehydrocholesterol to vitamin D3, which is carried to the liver, where it picks up extra oxygen and hydrogen molecules to become 25-hydroxyvitamin D (this is what doctors measure to detect deficiencies) and then kidneys, where it acquires a final pair of oxygen and hydrogen molecules, and is transformed to active vitamin D. Vitamin D deficiencies were rare when people worked more outdoors in fields and such, but as work shifted from farms to offices, that changed. In addition, deficiencies are often found in people with intestinal disorders, kidney or liver disease, and people who suffer from short gut syndrome.", "We have a molecule called 7-dehydrocholesterol, which, when properly struck by UV light, undergoes a chemical change into a precursor called Previtamin D3; it then converts to Vitamin D3 on its own (spontaneously, but not necessarily quickly)."], "text_urls": [[], [], []], "score": [24, 17, 6]}}, {"q_id": "5q6blk", "category": "Repost", "title": "National Debt", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dcwo5jq", "dcwrddf"], "text": ["> * How it works The US government issues Treasury Bills (aka T-Bills). These are low interest loans that the purchaser is giving to the government. They act something like \"Buy this T-Bill for $98, and in 2 years, we will pay you $100 for it\" > * Who the money goes to Whoever wants to buy it. Most of the US Debt is held by US Citizens and corporations. China owns about 7% of it. They have very low return on investment, but the US has always paid every single debt. It has never failed to do so. this makes it a safe investment. > * How much is healthy or not healthy This depends on the US' \"income.\" If you had a credit card debt of $100,000, that could be crippling. If Bill Gates had a credit card debt of $100,000, it would be completely negligible. So the amount that is healthy is the amount of debt that can be incurred (spending is good for the economy) while being able to comfortably pay it back. The \"income\" of the US is referred to as the GDP, Gross Domestic Product. > * What it would mean if we were \"positive\" (as in, instead of being $20T in debt, if we had a positive balance. If that makes sense?) Positive would be referred to as a Surplus. If there was a surplus that could be done in a way that doesn't harm the economy, that would be the best of both worlds (most likely, we would just borrow more anyway). Bill Clinton was the last president to have a budget surplus (not a surplus vs. the entire debt, but that the government earned more than it spent in the 10-year budget from Bill Clinton. George W. Bush gave everyone $300 on their taxes to spend that surplus)", "> - How it works > - Who the money goes to The US borrows money mainly by issuing treasury bonds -- fixed-term, low-interest loans. [Much of this debt]( URL_0 ) is held by governments, foreign citizens, and banks or mutual funds - anybody who needs to securely invest a large number of US dollars. Famously, the government of China owns many treasury notes, because they tend to have an excess of US dollars from trade, but exchanging these dollars for renminbi would increase the value of renminbi relative to dollars, making it more expensive for the US to import Chinese goods. > How much is healthy or not healthy Typically, a debt-to-GDP ratio below 100% is considered \"safe,\" although there is no hard-and-fast rule. It is obviously not sustainable for the debt to grow faster than the economy, and sustainable economic growth rates and interest rates typically hover around 2%. The US has the advantage of borrowing in a currency it controls, so it is unlikely to face a debt crisis like Venezuela (who borrows in US dollars) or Greece (who borrows in Euros) so it they can borrow quite safely. Whenever borrowing money can stimulate GDP growth at a faster rate than interest on the loan accumulates, it makes sense to do so. > - What it would mean if we were \"positive\" (as in, instead of being $20T in debt, if we had a positive balance. If that makes sense?) Your question makes sense, but it does not make sense to maintain a cash surplus. It would make more sense to decide how best to spend this money - by improving infrastructure or education, funding scientific research, etc. Cash sitting in a vault somewhere does nobody any good."], "text_urls": [[], ["https://en.wikipedia.org/wiki/National_debt_of_the_United_States#/media/File:Estimated_ownership_of_treasury_securities_by_year.gif"]], "score": [9, 4]}}, {"q_id": "5q8e7e", "category": "Repost", "title": "Why are men so attracted to breasts? What makes them so sexual?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dcxbj2x", "dcxd80u", "dcx9b2h", "dcx7n2w", "dcx8m0y", "dcxhzjy", "dcxcrrs", "dcxfegs", "dcxcalp", "dcxeiez", "dcxg4fy", "dcxgkvt", "dcxglin", "dcx79ah", "dcxkj36"], "text": ["They are indicators of fertility and so we are biologically programmed to be attracted to them. The same is true of having wide hips, and having shiny hair indicates good health. Breast firmness indicate age, so having developed and firm breasts indicates you are still young so potentially able to have more children, and having larger breasts indicates you have access to a stable food source so are a good potential mate. But these biological indicators are just starting points to things. Most of our infatuation is socially developed and due to a myriad of social factors including how taboo sex is or is not, and how taboo nudity is or is not. The more taboo something is, the more attractive we tend to find the things that skirt the limits of that taboo, or the violate it completely.", "Human breasts are unique among mammals with no other mammals having permanently swollen breasts. For other mammals their breasts are only engorged when nursing. Some anthropologists believe this is an adaptation to bipedalism, a frontal display of virility to supplement the view of gluts from behind. You'll notice the cleavage of breasts and the cleavage of butts are indistinguishable. * Edit This has some relevant info URL_0", "I don't want to discount any of the opinions offered, but the answer lies somewhere in the middle. There is an instinctual response as the shape and movement of a woman's breasts CAN indicate perceivable fertility and likelihood of successful child rearing. Humans vary, so hormonal variances, social stressers, and biological influence can factor into the level of sexuality breasts are designated. There are also psychological elements, experiences, and fetishes that can complicate matters further. Based on anecdotal evidence, anything more than a handful is just asking for a thumb sprain.", "Everyone loves breasts, not just men. They are a sign of having good genes and the being able to feed their young. It's primordial and ingrained on the genetic level really.", "Some societies don't sexualize breasts, so it isn't completely ingrained into our genes. They're sexual because they're hidden. They're attractive because they're forbidden. We grow up told they're sexual so we believe they're sexual. That's all there is to it.", "~~The thing is breast size and fertility aren't particularly related. However,~~ breast symmetry and fertility are. Women with symmetrical breast are more fertile than those asymmetrical breasts. An evolutionary theory is that, since it's easier to tell symmetry from bigger breasts, men gravitated towards that. As a side note, evolutionary psychology has found some pretty amazing things. For example, men are more attractive when they're surrounding by other women but women are more attractive when they're not with a man. (This applies to long-term heterosexual relationships) Edit: As promised, references. As I was rereading [the chapter]( URL_0 ), I realised I misread a word: breast size is not associated to milk production but it is to fertility. Sorry for the mistake. Here's the link to the original study, if you're interested Edit 2: the second link has a parenthesis so I have to post it directly: URL_1", "If large breasts are indication of good genes and good nourishment, then can someone please explain why some men are attracted to small breasts like me?", "Check this out: URL_0 Brin speculates that attraction to breasts is an evolved pedophilia-avoidance behavior: he writes that most of the common desirability signals for women are youth indicators, so attraction to boobs is your genes' way of distinguishing 'young and fertile' from 'way too young dude'. No idea if there's any verified science in the theory but it's an interesting read.", "It's half and half nurture and nature. Half is due to the fact that, as others have indicated, it's one of the visual indicators of fertility. However, a large part of it is also cultural, as the level of attraction and sexual taboo varies per culture, and cultures that put a heavy emphasis on sexuality of the breasts will perpetuate that.", "I learned in a documentary that they are some kind of replacement for the buttocks. When humans walked around on 4 legs (like monkeys still do). The view to the vagina was always in company with the buttocks. Later when the evolving human started to walk straight on two legs the line of view changed and a fake buttocks evolved way up higher. Edit: here is a link to this theory: URL_0", "I just want to put in here that big boobs do NOT mean a woman is more fertile and small boobs are NOT a sign that a woman can't feed her children.", "Took an anthropology class quite some time ago. Apparently, back when we were monkeys the female buttock was the major sign of fertility. When we started to stand up and become hominids or whatever the butt moved to the chest.", "I heard when evolution made us walk on two feet, the butt lost his ability to attract fertile males because it was no longer in middle of the field of view. So the breasts took over that role. Big breasts imitate the form of a juicy butt and are a sign that the female has the ability to feed her child and raise a strong descendant.", "So, women are attractive to men as a biological imperative to procreate. Wide hips and large breasts are indicators that a woman is more likely to be able to be biologically capable of childbearing and feeding breast milk, further enforcing the biological imperative with the increased odds of survival for the offspring. Personal note - These factors are largely irrelevant in civilized society, but biology is a stubborn bitch, and for that, we get to think boobies are awesome.", "The reason men are attracted to them is because they are withheld and sexualized by our culture. When I went to Spain and saw beautiful women with their tops off on the beach all around, the people around me imprinted on me a different attitude, and suddenly they stopped being what they were. When I came back to America, slowly they became sexual areas again"], "text_urls": [[], ["https://www.theguardian.com/science/2010/may/14/breast-size-evolution"], [], [], [], ["https://www.researchgate.net/publication/233285975_A_Brief_History_of_the_Theory_of_Evolution", "http://www.ehbonline.org/article/S0162-3095(97)00002-0/abstract"], [], ["http://www.davidbrin.com/nonfiction/neoteny2.html"], [], ["http://news.softpedia.com/news/Why-Do-Women-Have-Breasts-46783.shtml"], [], [], [], [], []], "score": [888, 112, 45, 35, 34, 28, 22, 20, 10, 6, 5, 4, 4, 4, 3]}}, {"q_id": "5q8tug", "category": "Repost", "title": "How are prescription glasses prescribed for infants?", "title_urls": {"url": []}, "selftext": "How do the physicians know whether or not they got it right?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dcx9lts"], "text": ["The machines are so advanced that they can scan retnas and determine optimal prescription without user imput. I just got new glasses with this method and never had to say what was worse or better, the machine did its thing and my new prescription is perfect."], "text_urls": [[]], "score": [11]}}, {"q_id": "5q96cf", "category": "Repost", "title": "Why can ocean water not be used and filtered for drinking water?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dcxcegj", "dcxctpi", "dcxczuv", "dcxfqv6"], "text": ["It is. It can be expensive to do this for large amounts of water, however, and the main issue is transporting that water to non-coastal cities. Simple evaporation combined with a condenser would purify most of the water.", "The city of Dubai is only possible because exactly this technology is used. As taggedjc said. You simply evaporate / cook water and add the right amount of minerals in after condensing it.", "[This article]( URL_0 ) is pretty much an ELI5 of desalination. What it really boils down to is cost but given regional water shortages, the cost is becoming less prohibitive.", "This can be done on an individual level. There are several survival/outdoors hand-pump based systems that use reverse osmosis to filter out pretty much everything, including salt."], "text_urls": [[], [], ["https://www.scientificamerican.com/article/why-dont-we-get-our-drinking-water-from-the-ocean/"], []], "score": [44, 13, 5, 3]}}, {"q_id": "5q975p", "category": "Repost", "title": "How did Hitler rise to power?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dcxcwa2", "dcxcs7s", "dcxgjmx"], "text": ["This will be a quite oversimplification. Pre World War I, Germany had an authoritarian government (Kaiser was like the Emperor). After, there was a democratic reform. Consequently, World War I occured where Germany suffered a terrible defeat. Not only did they have to pay reparations, they also had to sign the War Guilt Clause. That taken account with ravaged German infrastructure and economy led people to have a general dislike for the democratic government. Hitler's Nazi Party had a platform that appealed to industrialists, and offered to restore 'honour' to the German people. Furthermore, he said that all problems that Germany was facing were a result of the Jews; effectively directing discontent. Furthermore, he invited blind nationalism by arguing the superiority of the Germans. Although he seemed the appeal to the German citizens, who were probably desperate for any strand of hope, never actually had/formed a majority government. In fact, the most seats they had in the Reichstag were 33%. Eventually Hitler was elected Chancellor. A combination of the President's death and the burning of the Reichstag, led to Hitler passing the Enabking Act of 1933 DEMOCRATICALLY. That Act dissolved democracy and concentrated all power in the hands of Hitler. The only reason why this passed, democratically mind you, was because a) the German people were desperate for stability, and b) Hitler promised to restore stability and eventually reinstate democracy once stability was reached. As it has gone in history, Hitler never returned democracy and ala World War 2 eventually ensued after the invasion of Poland.", "Like the populists do it today. He promised everybody what they wanted to hear while presenting \"alternative facts\". He found a scapegoat for the people to blame for their own faults: Foreigners, yews (Muslims weren't broadly known then). He promised jobs, he promised higher wages. He said \"Germany first!\". He used easy to understand paroles so that even the dumbest person could scream them. He blamed his predecessors for everything bad and even twisted the truth to depict good social changes from his predecessors as something bad. By the way...Any resemblance to a living politician is purely coincidental, likewise the resemblance to fish.", "Top-level comment because this is important, but quoting /u/MLBlaster: > Hitler passing the Enabking Act of 1933 DEMOCRATICALLY One thing about the way the Enabling Act was passed is that it was lots of things, but it wasn't democratic. Hitler's party, the NSDAP (the \"Nazi\" party) had just been elected with 44% (not 33%) of the votes, just short of the absolute majority he wanted. This meant he had to form a coalition, and this was going to make life really difficult. An Enabling Act is a piece of legislation that grants the government temporary powers to deal with an emergency, so this is how the Reichstag fire played into this. But that kind of legislation needed a 2/3 majority to pass, and the Nazis weren't going to get that without some skulduggery. And there was a lot of skulduggery. Before the crucial vote, the Nazis managed to force through a change in parliamentary procedure. For the vote to be valid, at least 2/3 of the elected members needed to be present; the risk was that some of the left-wing parties might simply stay away and render the assembly inquorate. The change meant that any member who was absent without leave was deemed to be present, but this included about 200 members who had already been thrown into prison. As a result, it wasn't possible to sabotage the vote simply by walking out. The Nazis also posted members of their own paramilitary wing, the SA, outside the debating chamber (which, following the Reichstag fire, was now in a nearby opera house) in order to intimidate members. Later, one of the members who was there wrote that if the Nazis hadn't been allowed to do this (it was transparently illegal, but nobody was brave enough to stop them), they'd have lost the vote. Many members had even received threats to their own lives, and the lives and security of their families. The Nazis relied mostly on the votes of the Centre Party, which was deeply divided over the issue, and the Bavarian People's Party. Hitler secured their vote by making certain assurances -- basically saying, \"I won't turn Germany into a totalitarian dictatorship, scout's honour, cross my heart, etc. etc.\" That was, of course, an outright lie: Hitler had no intention of keeping his promises. And that's how the Enabling Act was passed: a mixture of political sleight-of-hand, deliberate deception and straightforward bullying. It wasn't democratic by anyone's standards, but nobody was brave enough to stand up to Hitler. Not surprisingly: 200 of their colleagues had been arrested or were on the run, and they were being threatened and intimidated."], "text_urls": [[], [], []], "score": [7, 3, 3]}}, {"q_id": "5q9cil", "category": "Repost", "title": "if you have two videos of equal duration, why aren't their file sizes the same?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dcxdrts"], "text": ["Because video files are compressed. Compression depends on various factors such as how good the compression algorithm is, the level of compression (more compression = lower quality video) and how compressible is the video (for example a video of a blank screen is a lot more compressible than an action scene - see [this video]( URL_0 ) for a demonstration)."], "text_urls": [["https://www.youtube.com/watch?v=r6Rp-uo6HmI"]], "score": [5]}}, {"q_id": "5qa50b", "category": "Repost", "title": "what is the feeling of a 'knotted stomach' or butterflies in your belly", "title_urls": {"url": []}, "selftext": "And what physiologically causes us to feel it", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dcxtq8q"], "text": ["Stomach butterflies are associated with the body\u2019s fight-or-flight response. When the brain perceives a potential threat to survival, it increases alertness by raising heart rate, blood pressure, and breathing rate. At the same time, the nervous system stimulates the adrenal glands, which release hormones including adrenaline and cortisol that can make the body tense. This causes the stomach muscles to get extra-sensitive during the fight-or-flight response, and that's partially what causes the butterflies. Neurons along the brain-gut axis let the stomach know when we're freaking out about something which adds to the butterfly effect. Butterflies and the fight-or-flight response are thought to serve an evolutionary function."], "text_urls": [[]], "score": [11]}}, {"q_id": "5qbph0", "category": "Repost", "title": "I'm arguing with dumb relatives on Facebook- can some one please explain global warming like I'm ACTUALLY FIVE?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dcxwpgv"], "text": ["Human make carbon pollution. Trap heat. Earth get hot. Climate changes. Bambi can't handle it. Bambi dies."], "text_urls": [[]], "score": [3]}}, {"q_id": "5qfz1l", "category": "Repost", "title": "Why do we sometimes feel more awake with little sleep, but feel more sleepy after a lot of sleep?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dcyzmfx"], "text": ["This has been discussed on reddit before, but it has to do with natural sleep cycles. We each have natural sleep cycles; the common theory seems to be that most of us have natural sleep rhythms that occur in roughly 90 minute cycles. If you interrupt this cycle, you feel less refreshed and groggy. If you wake at the natural end of one of these cycles you feel like you've had a good sleep. We don't all follow the 90 minute average, but using that as an example, if you only slept for 3 hours (2x 90 minutes) you might wake up and feel great. If you slept for 7 hours (4.666 x 90 minutes) you would interrupt your sleep in the middle of a natural sleep cycle, and feel like you have not slept well. If 90 minutes actually is a reliable average of people's sleep cycles, the common advice of \"8 hours of sleep\" would be ill-advised. That means you would wake in 5.33 sleep cycles. You'd be better off to sleep for 7.5 hours, or 9 hours."], "text_urls": [[]], "score": [6]}}, {"q_id": "5qglv4", "category": "Repost", "title": "Wouldn't a 20% tariff on Mexican products ultimately end with US citizens paying for the wall?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dcz1wjl", "dcz1uax", "dcz1wg7", "dcz6czn", "dcz5n06"], "text": ["Correct. Prices will go up for the American consumer. Mexican companies will start to look for other markets in which to sell their goods. If they can't then the job market in Mexico will become more difficult, thereby increasing the incentive for them to enter our country, legally or not.", "More than beer comes from there, my friend. A significant amount of food produce is grown in Mexico. And tes, such a tariff would make everyday purchases go significantly up for every American. And yes, Americans would be paying for the wall.", "The general idea is that if there was a 20% tariff on Mexican goods then the price would spike and american citizens wouldn't buy them. Its more of a threat than an actual way to get money from mexico to finance the wall. Its also a terrible plan because their aren't enough U.S goods that compete with Mexican and citizens would end up paying for it.", "It's not really a 20% tariff they're talking about. URL_0 > A tax on imports, but not on exports. This sounds like a tariff. > A border adjustment is not a tariff, nor would it give the U.S. a trade advantage. > At first glance, a border adjustment sounds like a tariff because it applies to imports, but does not apply to exports. The adoption of a border-adjustable tax is sometimes praised as a cure for the U.S. trade deficit, or promoted as giving the U.S. a competitive edge, or offsetting a competitive edge now enjoyed by foreign producers whose countries use border-adjusted taxes. Such claims are unfounded, and based on a misunderstanding. For instance, Senator Ted Cruz wrongly argued that his plan would benefit exports. > A border-adjusted tax falls equally on domestic and imported goods, in order to tax the amount of income people spend on consumption. A domestically produced good and an imported good will face the same tax. Goods produced in the U.S. and exported abroad are exempt from taxation, but exports are not consumed at home. However, the foreign buyer may be subject to a consumption tax levied in his home country, but that is not the concern of the U.S. taxing authority. > Of course, U.S. producers may think of this as a subsidy for exports because they would not be taxed on sales overseas. But if businesses were able to reduce the prices of their goods they sell overseas due to the border adjustment, this would trigger a higher demand for dollars in order to purchase those goods. This higher demand for dollars would increase the value of the dollar relative to foreign currencies and offset any perceived trade advantage granted by the border adjustment. Most of the media has gotten this wrong because they are English majors and don't understand economics.", "It will also lead to a huge surge in illegal immigration. If jobs leave Mexico people will have no choice but to follow them."], "text_urls": [[], [], [], ["https://taxfoundation.org/house-gop-s-destination-based-cash-flow-tax-explained"], []], "score": [37, 11, 10, 10, 5]}}, {"q_id": "5qgodg", "category": "Repost", "title": "Black American accent/dialect", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dcz38xr", "dcz2ef7"], "text": ["This is phenomenon that sociolinguistics describes as [Speech Communities]( URL_1 ). here's a quick snippet from wikipedia. > Speech community is a concept in sociolinguistics that describes a distinct group of people who use language in a unique and mutually accepted way among themselves. This is sometimes referred to as a Sprechbund. > To be considered part of a speech community, one must have a communicative competence. That is, the speaker has the ability to use language in a way that is appropriate in the given situation. It is possible for a speaker to be communicatively competent in more than one language.[10] Speaking the socially acceptable way correctly is one way others in the group can recognize you as a \"member.\" A counterexample to this would be the stereotypical nerdy old guy trying and failing to relate to teenagers by adapting their language. > Speech communities can be members of a profession with a specialized jargon, distinct social groups like high school students or hip hop fans, or even tight-knit groups like families and friends. Members of speech communities will often develop slang or jargon to serve the group's special purposes and priorities. We all conform to different language structures and vocabulary depending on what context we're in. Most of the time, we're not accutely aware of this, but if something breaks norms, they risk isolating themselves. You know that guy who shows up at college parties using big words trying to show off how intelligent he is. We're all subject to social pressures to conform to the standard langauge, and black people can be criticized for \"talking white\" among peers, just like white people can be criticized for \"talking black\" in the same context. Keenan Michael Key from Key and Peele said in an interview that his parents were college professors or something, and insisted he speak standard english at home, but at school he would fall into black vernacular english with his classmates and friends. > Community of Practice allows for sociolinguistics to examine the relationship between socialization, competence, and identity. Since identity is a very complex structure, studying language socialization is a means to examine the micro interactional level of practical activity (everyday activities). The learning of a language is greatly influenced by family but it is supported by the larger local surroundings, such as school, sports teams, or religion. Speech communities may exist within a larger community of practice.[11] EDIT So language is highly socialized and strongly tied to identity, which is a difficult concept to parse. Ben Carson maybe speaks with his family and old friends in typical black vernacular english, but would speak to a fellow doctors in a completely different way, while adapting yet another langauge in political circles. (I'm not sure how true this is for Carson specifically, but you get the idea.) You can also delve deeper into the concept of speech communities by reading the [full wikipedia page]( URL_0 ) Edit its also worth mentioning that black people in the Northern part of the country aren't far removed from southern black communities. The vast majority of black people lived in the southern US until the mid 20th century and the Great Migration, which saw an influx of black people moving to other regions of the US, like the Midwest, northeast and West. They brought their culture and their language with them and since they came in such great numbers, it remained intact.", "Different groups develop different dialects if they don't intermingle much- it's why you'll find people in different social strata sound different. (The guy in the bleachers at Fenway and the Kennedys aren't exactly talking with the dialect.) Since African Americans have been pushed out of main (white) Society for so long, first by slavery and then by decades of racism, they've developed their own dialects as well. You'll see the same thing in other racial groups in America, and though you might think someone from Boston and Alabama sound the same, they likely can tell the difference far more easily than you can."], "text_urls": [["https://en.wikipedia.org/wiki/Speech_community", "https://en.wikipedia.org/wiki/Sociolinguistics#Speech_community"], []], "score": [6, 4]}}, {"q_id": "5qgwgr", "category": "Repost", "title": "How have we come so far with visual technology like 4k and 8k screens but a phone call still sounds like am radio?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dcznw5i", "dczjkiq", "dcz6hod", "dcz49vo", "dczfral", "dczjtw0", "dczmzeh", "dczlj2k", "dczjj4t", "dczoboi", "dczn4er", "dczubyh", "dczs5yp", "dcziybz", "dczlev3", "dczd2k0", "dczgf7d", "dcz4yi6", "dczpskp"], "text": ["The reason phone calls don't have perfect audio has all to do with three things. * Bandwidth * Physical medium of the delivery technology * The codec used They are all closely related. If you think of a data connection as a water pipe, there is only so much data that can be passed down the connection, just like a water pipe can only carry so many gallons of water a second. If you make the water pipe bigger, the pipe can carry more gallons a second and deliver more water faster to its source. This is broadly comparable to using better connectivity for our data connections. For example fibre optic cable can carry much more data a lot faster than the copper cables that are used to connect most of our homes. To that end, when a phone conversation is initiated between two people, the sound of the voices from each party is in fact, a data connection that gets converted into an analogue frequency. Now uncompressed audio takes up a lot of space and can be slow to transfer, so to reduce it down to something more manageable, phone systems use something called a CODEC (en*CO*de/*DEC*ode) that basically analyses the audio, and throws out the bits of data that it thinks is not relevant to the clarity of the conversation. The more data it throws out, the more \"AM Radio\" the conversation sounds. The standard codec used by most public telephone systems (Generally known as the \"PSTN\" to phone engineers or \"Public Switched Telephone Network\") is something called U-LAW. Europe uses a variation of it called A-LAW. It allows 64Kbp/s of data for each way of the conversation (So 128Kbp/s total). It's been around since the 70's and is fairly embedded into most phone systems. It also closely matched and fitted the best data rate offered by twisted copper connections that where used at the time (And predominantly still are). The days of the \"AM radio\" phone call are coming to an end though, if quite slowly. Many new codecs have been developed alongside newer communications technology since the 70's that allow for greater clarity in a phone conversation. They do this by improved methods of packing in the audio data and more sophisticated ways of deciding what parts of the audio need to be thrown away and what needs to be kept. Some are even able to do this using a smaller transfer speed than the U-LAW codec. Most of these improved quality codecs are referred to as wideband codecs or \"HD audio\". This has come about with the rise of a technology called VOIP or \"Voice Over IP\" which is basically a phone system that utilizes the same technology that underpins the internet (TCP/IP) to deliver an all digital phone service. One of the most popular codecs used by internal phone systems of companies/organizations (Which is sometimes referred to as a PBX or Private Branch Exchange) is a codec called G722. The difference in audio quality between G722 and U-LAW is like night and day. Cellular technology is also catching up on the wideband conversation game. Indeed many mobile carriers are offering wideband calls between users on the same network. This uses a codec called AMR-WB. It's generally predicted within ten years or so wideband audio for mobile phone calls will become the norm **where supported**. I emphasise that \"Where supported\" bit because like most communication methods, a phone call has to negotiate down to the level of the lowest offering. So if a phone conversation is initiated between two phone systems, one side tries to use a wideband codec like G722 and the other side only supports U-LAW, then both phones will use U-LAW and the conversation will return to the \"AM Radio\" quality for both callers.", "The history of the telephone began with Plain Old Telephone Service (POTS) which simply refers to the old, analog phone system we used for the first 100 or so years. Although humans (young ones anyways) can hear a range of frequencies between 20hz and 20,000hz, the vast majority of human speech is well below 4,000hz. The original designers of the POTS system designed what became known as a standard Voice Grade Channel (VGC) with practical limits due to the way electronic circuits worked so a standard VGC was typically 300hz to 3,400hz. When we switched to digital telephones they simply continued that standard by digitally sampling voice and consuming that same amount of bandwidth. Fun fact. I worked with digital, encrypted telephones when I was in the Air Force and depending on the quality of the phone line and the bandwidth available, the encrypted phone would start at 4,000hz bandwidth and throttle to a smaller bandwidth if it couldn't maintain synchronization. At half that standard bandwidth or 2,000hz the quality of the speech reduced so you wouldn't recognize your own mom. At half again of that or 1,000hz you could barely understand it and could not recognize male from female speakers on the other end", "Also: it's got to be compatible with all phones on the network; theoretically your call might be digitised then turned analogue then digitised then turned analogue then digitised then sent analogue down a 100-year-old rusty copper line into a 50 year old handset. Lower common denominator.", "Have ~~no~~ you not had an HD Voice (aka Wideband Audio) call? Most all carriers support it now, ~~by~~ but it's only if both parties have the same carrier and supported devices. T-Mobile even has a more advanced audio quality feature for a handful of phones. As for why normal calls are low quality, because that's what is decent enough to understand people, and improving that quality is way too expensive compared to implementing Wideband Audio which simply uses VoIP (the VoLTE setting on your phone).", "I worked in telecom a long time and the answer is rather surprising. People prefer it this way. Back in the switch to digital many telecom companies converted early to save on replacing outdated multiplexing equipment. The resulting clean zero ambient noise calls actually irritated customers and made them anxious that the phone wasn't working. So they added the noise back manually.", "To save on bandwidth, many of the audio codec compresses in a lossy format to squeeze more active calls simultaneously. There are lots of phone in a given region, and there's never enough capacity to carry all the phones calling at the same time. There's also the problem that if you don't have at least a bit of noise on the phone, people think it is not working, so even if you are in a quiet room calling another phone in a quiet room, you're likely to hear some white noise to help you differentiate between an active call with silence on the line vs a phone without an active call. Most carriers in North America should have HD voice, which should improve voice quality. But it's definitely possible that if you make a call through a network that doesn't support it, the call falls back to the older standards. In Hong Kong a couple of years ago, any calls to CMHK number would sound worse than other carriers.", "If you call a Cisco (or other) digital VOIP phone within the same network/building, it's so crystal clear, it's like the other person is standing next to you. It's actually kind of unsettling because it doesn't sound like a \"phone\" anymore.", "Let me shine here for a while: at the moment in the US and in the World the mobile networks still widely use 20+ years old standards for voice calls: 2G (GSM) and 3G (CDMA, WCDMA). They are still following the same voice codecs created and standartized for handset (phone) equimpent in late 80s (GSM) and mid 90s (CDMA/WCDMA). In order to keep old equipment still able to use modern network, they do not switch of completely such dinosaur codecs as HR, FR, AMR and are unable to replace them by more modern. Older mobile networks is a mess of old and new equipment which is not always economically feasible to replace/upgrade, so it is still the case you could hear voice quality similar or just slightly above than brick Nokia from mid 90's. As for modern 4G (LTE) network the standard itself offers quite good codecs on par is what used in Facetime or Skype, but the introduction of Voice Over LTE (VoLTE) is such pain in the ass, as you should retroactively support all possible connection combinations like calling from old phone old 2G base station to the new VoLTE 4G Samsung and therefor VoLTE is not adopted widely.", "There is considerably less demand for high definition voice calling than there is for high definition televisions and screens in general. If anything, there is less demand than ever for high definition audio calling as texting has replaced a lot of calling.", "I read all the comments so far and didn't see one thing that's very important for sound quality: the electric to sound transducer, the \"speaker\" at the end of the chain. Your phone sounds like an AM radio because the speaker is built like an AM radio. It has a very small membrane that vibrates, it cannot reproduce bass sounds well because it's too small. If you listen to a phone call through high quality headphones or speakers you'll hear a much better sound.", "Others have answered the original question very well, but maybe as a sound engineer I can add something about why so many telecom companies still use low bandwidth for voice, even though high definition sound is available, variously branded as HD Voice or Wideband Audio. Much of what we hear is actually an illusion. Our brain fills in the sounds it expects to hear based upon what it has heard before. So, much like Compact Disc worked by filtering out certain frequencies so that huge amounts of information could be squeezed onto a format which could only store around 750MB of data, the telephone system is also designed to carry *just enough* sound information, so that our ears can reconstruct what they expect to hear in an ordinary human voice. To demonstrate this to your own satisfaction, you could ask someone you're talking with to play music over the phone. The quality quickly dips into an indiscernible mess, because there's too much sound information for the digital converter software running on the telephone company's computers to process it in such a way that it fits into the available bandwidth. However, as anyone who has ever been placed on-hold will tell you, the muzak which plays is clear enough to listen to (albeit for only a short amount of time, before losing your mind). This is because it has been *squeezed* electronically so that it only takes up the same space which would ordinarily be used by the human voice, meaning that the telephone network effectively *sees* it as such. The reason the networks do this is down to costs. You can squeeze many more separate point to point phone calls down a single fiberoptic cable if none of the data which would be necessary for a full HD quality stream is included. To get around this HD Voice systems tend to rely on the user's handset to do the encoding and decoding which would have traditionally been performed by the phone company's equipment. This is only possible because it uses the increased processing power now available on modern smart phones, but it tends to introduce a slight delay because the software running on both phones 'waits' for enough information to reconstruct a clear sound before sending it down the line. This delay can be negligible if you and the person you're talking to are geographically close to one another, but it becomes noticeably worse if you're making an international call - where the delay is similar to those which cause problems for live satellite link-up TV news reports.", "Short short answer, is bandwidth efficiency. Back in the day, prior to mobile communications, telephony was 'circuit switched'. This meant that when communicating from point A to point B, dedicated resources would be assigned on all the equipment between. As there was always a limit to the amount of resources available, the algorithms used to compress voice into transmittable data favoured very high compression over voice quality. If the number of calls exceeds the available resources, then calls are not connected. You can imagine this like the old style telephone operators connecting calls. If there were more calls than operators, some calls wouldn't be connected. The internet, and data networks, are packet switched. This means that rather than reserving dedicated resources between two endpoints, the resources are shared. The upshot of this is that when resources are highly available, you get very high performance. As the resources drop the performance for all drops, but the communications continues for all (albeit at a lower rate). Now lets fast forward to mobile communications. You'd think it's all packet switched right? Well, no. Mobile telephony was built as a concept long before data transmissions to mobile phones was considered. As a result, mobile phone calls were always (and in almost all cases still are) circuit switched. As a result of this, and the fact that earlier radio technologies (2G/3G) had much lower available bandwidth high compression algorithms (codec's) are mainly used. Now, in 2G and 3G mobile telephony, the codec's used are AMR (Adaptive Multi Rate) and AMR-WB (Adaptive Multi Rate Wide Band - otherwise known as HD Voice). The Adaptive Multi Rate codecs are pretty clever, as they can scale their quality/efficiency based on the available bandwidth. With 2G and 3G radio's, bandwidth is directly related to signal strength. So as the signal strength drops, the quality drops. Now lets move up to today, and 4G. Unlike 2G and 3G radio's, the bandwidth of 4G isn't directly related to the signal strength, and as a result can maintain higher quality calls at weaker signal strengths. Additionally, where with 2G and 3G data is transmitted as a packet switched network over the circuit switched bearer, with 4G it's an entirely packet switched network and the voice (know as VoLTE, Voice over LTE) is carried out exactly like a VoIP phone (although the technical specs elaborate on is massively). However, almost all carriers that deploy 4G, use 'Circuit Switched Fallback' for voice, meaning that when placing or receiving a phone call the mobile phone falls back to 2G or 3G to connect the call. This is mainly because most carriers haven't yet deployed VoLTE. The combinations of these technologies mean that when you connect a call using AMR-WB over 4G (VoLTE), it supports higher bandwidth modes than over 3G, so you get even better quality. Sadly VoLTE isn't widely deployed, and even HD voice on 3G isn't that widely deployed, and when you call up your friend it doesn't matter if your phone/carrier supports the top end voice codec's if the other end is stuck on a circuit switched (2G/3G or fixed line) connection. Credentials: Telephony Consultant, specialising in VoLTE and Fixed Line IMS Edit: Grammar, spelling and some expanded information on the lack of VoLTE service worldwide", "Try FaceTime audio, digital and makes a difference. Why all providers can't use this?", "The issue is the bandwidth of the radio lines, your phone can record and output your voice just fine. Correct me if I'm wrong, but you can hear about 20kHz, the radio has bandwidth for only 2. To perfectly mimic real voice you have to utilize something that does not require as much bandwidth. But because of the frequency this isn't really faisable. So basically, data becomes lost and all that's left is a bad but understandable 2kHz audio signal. Also, lower frequency automatically means lower baudrate, thus a slower transmission speed is sufficient.", "It basically boils down to cost vs. demand. Higher quality audio requires higher quality analog POTS lines (Plain Old Telephone Service) or more bandwidth for digital voice. Both of those things are a cost to the carrier (AT & T, Verizon, etc). But would you pay any amount more for better audio quality? Virtually no consumer will, so the carrier finds the lowest balance between audio quality and customer complaints in order to maximize profits. High quality audio calls are totally a thing, but you have to have a device on both end that supports it as well as a proper network to support it every hop of the way between both endpoints. You won't see this on much consumer equipment because consumers won't pay for it. But you will see it a lot more on private phone systems where the carrier isn't involved, like intra-office calling on a VoIP system (voice over internet). Source: a decade working in telecom and explaining to customers that their calls sound like shit because they won't pay for quality audio lines/bandwidth.", "LPT: Google hangouts has some of the best audio quality for free. Works great on LTE or on Wifi and you can choose to use the video feature as well or turn it off.", "There's also a technological thing going. Voice gets priority over data transmission. You don't want any delays not do you want missing days package resulting in voice doing out. This is why voice data is not in high bandwidth. This goes through easier.", "Basically, people are not ready to pay more for more quality of voice during their call. Especially since most people text these days. So company probably tested that and figure out that it would cost them money to upgrade their system in term of quality of voice, and that they would probably lose consumer because of their higher prices. But people are happy to pay more to get better looking tv Show and movies.", "A long time ago when previous generation phone networks were being built, there was very limited capacity in the system so a decision was made to only allow X amount of that capacity per call. This way the system could carry more calls that sounded \"OK\" vs a fewer number of calls that sounded \"Good\". It was simply a compromise toward capacity vs performance. These days, there are actually quite a lot of scenarios where that no longer applies and calls should sound much better. For instance, an end to end VoIP call that doesn't traverse the public telephone network (PSTN) at all. Think of Skype, Google Hangouts, Ventrio, Teamspeak, an internal call at a business using a VoIP phone system, etc. Those calls will generally sound much better than a standard phone call transiting the PSTN because they can use much more bandwidth. Of course, this is assuming that the IP network in between the two endpoints is performing well, has relatively low latency/jitter, and has sufficient available bandwidth. VoLTE (Voice over LTE) is something a lot of cell phone companies have now, which basically uses VoIP behind the scenes. This only works when the entire call path is on a compatible network (i.e. if you call a PSTN phone from your VoLTE-compatible cell phone, you're not getting VoLTE end to end so you're not going to get the better call quality, but if you called another cell VoLTE-compatible cell phone on the same carrier you should). Some parts of the PSTN are better than others. For instance, many businesses use ISDN or SIP instead of regular analog phone lines (like what you'd typically have at your home) and these are both digital technologies. So, in some circumstances, even a call you place over the PSTN could be digital end to end, and that call will typically sound better than a call that's transiting an analog network, although it usually won't sound as good as a VoIP call."], "text_urls": [[], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], []], "score": [1622, 1200, 888, 670, 423, 299, 30, 30, 20, 15, 8, 7, 5, 4, 4, 3, 3, 3, 3]}}, {"q_id": "5qgyv0", "category": "Repost", "title": "Why do countries have huge 'national debt' and 'deficits' even if they are wealthy countries in general?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dcz66mm", "dcz8lrc", "dczipsb", "dczk653"], "text": ["It's all about rate of return. If my country has $1bil to invest into itself for the year, I can pour it into Solar Panel manufacturer subsides and make 10% back for the populace. The smart guys that make these estimates say that if I were to spend up to $3bil I would still make 10%. But I only have the $1bil, so to really maximize my gains, it would make good business sense to see if anyone else wants in on my solar panel action. So I start selling bonds at a 4% interest rate. Citizens, countries, companies, anyone can buy them. I'll owe them 4% every year on the $2bil we had to borrow, but I'll make 6% on that $2bil through solar panel sales. That's an extra $120mil that I give back to my people that I wouldn't have had without debt financing. The real catch is whether those estimates were accurate, and we could execute close to the assumptions they had to make. Once those bonds are sold, I definitely HAVE to pay $2bil + 4% interest to my debtors, even if we find out that the Solar Panel guys were just selling cardboard and construction paper. Just like household debt, it's not inherently bad if those making the financial decisions are responsible.", "National debt isn't necessarily a bad thing, you have to look at it a little bit differently than house hold debt. For instance, the USA is about 19.5 trillion in debt. This doesn't mean that they have gone out and asked to borrow different countries for trillions of dollars. If you've ever been given a US savings bond, then the united states owes you money, and this is where the national debt comes from. Investors use these bonds as a low risk investment for a nearly guaranteed return. You have to look at the debt as an investment opportunity. A 30yr t-bond has an interest rate of about 3%. So if you bought a $1,000 bond, the US government is paying you $30 per year for that money, and in turn the government gets to finance national security, social security, infrastructure, etc. So that's all well and good, what about paying it? Like I said, US bonds are considered an extremely safe investment because they are backed by the US government, so they are basically guaranteed to be paid back. The confidence level is based on multiple things, but a key indicator is the Debt to GDP ratio. The [ratio]( URL_0 ) for 2016 was 71.8%, meaning that 72 cents of every dollar that the US takes in from taxes goes to servicing debt. To answer your question as to why does this happen? It happens because there is a demand for debt. As long as there is a demand for bonds, then the US and other countries will continue to issue them. If demand were to go down, then the interest yields would go down to a point that they weren't really worth investing in, and investors would be forced to move in to other investments.", "Because having debt isn't in an of itself a bad thing, and the wealthier you are, the more confidence you lenders have in your debts being paid back. When you buy a house, you take on a huge amount of debt and have to pay interest on it. But this is usually good for in the long run...having a house **now** will benefit you more than saving up and buying a house outright 10-20 years from now. National debt works the same way. Having a bridge or school or airport **now** is worth the interest you would pay in the long run.", "Having a lot of debt is a measure of your wealth. The US is able to rack up so much debt because they have the ability to pay it all back. They continually invest their earnings. The same is said for any major tech company. Amazon rarely ever turns a profit, but they are one of the largest and wealthiest companies. This is because they put all their profits back into the company."], "text_urls": [[], ["https://en.wikipedia.org/wiki/Debt-to-GDP_ratio"], [], []], "score": [89, 13, 8, 4]}}, {"q_id": "5qicwo", "category": "Repost", "title": "why do we have finger and hand prints?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dczfyzr"], "text": ["Grip. So when we go to pick things up or pull ourselves into something, there's variable traction. This is also why the skin on your hands and feet are tougher. As for the prints themselves, genetic uniqueness"], "text_urls": [[]], "score": [3]}}, {"q_id": "5qlbf7", "category": "Repost", "title": "Why/how is lobbying allowed?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dd064lg", "dd05z8b"], "text": ["> I see it as some sort of bribery Lobbying is informing the representatives of the people what a group of people want them to do. You can't very well have a representative democracy if the people being represented can't inform their speakers what they should say. Lobbyists are professional messengers. Cleetus on the farm has strong views but he works at the farm all day and isn't the best speaker. He and his extended family can hire a city slicker who talks like greased lightning and has a silver tongue to sit in town all day and chat up the representatives for Cleetus and everyone. This is all perfectly legal and proper. How would you stop it? Can you tell the city boy that he can't be any more clever a talker than Cleetus? Can you tell Cleetus he can't talk to the representatives any more often than Jimbob who can't be arsed to ever leave his hut in the hills? Of course not! So professionals who spend all day trying to push the message of interested parties are here to stay.", "Bribery itself is forbidden, lobbying in its allowed form not. Essentially it is supposed to be representatives from different branches talking to politicians about possible law changes or to tell them about flaws in proposed ones. This in itself is not so bad, politicians are seldom knowledgeable about their work or did not work in the industry to know about unforeseen consequences of laws. Expert groups are good and well but on-hand experience is valuable too. The problem is , the system does not work this way. The intentions while noble are forgotten. Nowadays it's just big players getting their will , instead of offering advise. Open bribes will still be persecuted but the practice itself is still legal under the pretense that it works like I stated above."], "text_urls": [[], []], "score": [6, 4]}}, {"q_id": "5qmvan", "category": "Repost", "title": "Where is the Center of Universe?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dd0ik53"], "text": ["There is no centre of the universe! According to the standard theories of cosmology, the universe started with a \"Big Bang\" about 14 thousand million years ago and has been expanding ever since. Yet there is no centre to the expansion; it is the same everywhere. The Big Bang should not be visualised as an ordinary explosion. The universe is not expanding out from a centre into space; rather, the whole universe is expanding and it is doing so equally at all places, as far as we can tell. In 1929 Edwin Hubble announced that he had measured the speed of galaxies at different distances from us, and had discovered that the farther they were, the faster they were receding. This might suggest that we are at the centre of the expanding universe, but in fact if the universe is expanding uniformly according to Hubble's law, then it will appear to do so from any vantage point. If we see a galaxy B receding from us at 10,000 km/s, an alien in galaxy B will see our galaxy A receding from it at 10,000 km/s in the opposite direction. Another galaxy C twice as far away in the same direction as B will be seen by us as receding at 20,000 km/s. The alien will see it receding at 10,000 km/s: A B C From A 0 km/s 10,000 km/s 20,000 km/s From B -10,000 km/s 0 km/s 10,000 km/s So from the point of view of the alien at B, everything is expanding away from it, whichever direction it looks in, just the same as it does for us."], "text_urls": [[]], "score": [9]}}, {"q_id": "5qo9b6", "category": "Repost", "title": "Why are socialists considered \"left\" and extremism \"right\"? Why not the other way around?", "title_urls": {"url": []}, "selftext": "I've been thinking about this for some time.. I'd like to know why one is called \"left\" or \"right\" and not the other way around.", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dd0rp0s", "dd0rnpg", "dd0uglq"], "text": ["It comes from around the time of the French Revolution. In the National Assembly supporters of the king sat on the right and revolutionaries sat on the left. People started referring to either side as the left or the right and it's been carried on from there.", "Fundamentalists are right wing, and can tend to be extreme. There have been plenty of left extremists (like the Bolsheviks). No one has a monopoly on extremism. If you want to diagram it, it's easier to add a Y axis and make a [Political Compass]( URL_0 ) There's left and right, and then on the Y axis, there are Authoritarian and Libertarian. Communism is left and authoritarian (socialism is too, but it's closer to the middle between authoritarian and libertarian). Fascism is right and Authoritarian.", "\"[Extremism]( URL_0 )\" is mostly a pejorative, not an actual ideology."], "text_urls": [[], ["https://en.wikipedia.org/wiki/Political_compass"], ["https://en.m.wikipedia.org/wiki/Extremism"]], "score": [34, 9, 7]}}, {"q_id": "5qp08n", "category": "Repost", "title": "How do executive orders work in a system of checks and balances in the US democracy?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dd0x9qn"], "text": ["1) They are limited in scope. They can only instruct the various departments of the Executive Branch on how to implement current laws. He cannot create new laws. 2) If the President over reaches too much the order can be overturned by the Supreme Court as being unconstitutional. 3) If the President over reaches too often or too severely he can be impeached by congress."], "text_urls": [[]], "score": [5]}}, {"q_id": "5qu8gj", "category": "Repost", "title": "why in old hand drawn cartoons items that are gonna be intervened with look lighter or different from the rest of the background?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dd24ft0"], "text": ["Cartoons back then were animated using layers, similar to how you would on Photoshop. The back layer holds the background, and is made to be set and forgotten about. If a character is called on to interact with a background piece, that piece is pulled into the foreground layer. Because of the methods they used, as the video ages, and video playback becomes more detailed, the contrast between the fore and background layers becomes more noticeably different, and you can see the transition more easily."], "text_urls": [[]], "score": [5]}}, {"q_id": "5qutec", "category": "Repost", "title": "Why is 100\u00b0F air extremely hot and uncomfortable for humans, while 100\u00b0F water is slightly warm and pleasant?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dd2aw0x", "dd2ata7", "dd2d7yn", "dd2qt94", "dd2o3hf"], "text": ["I've seen this answered a million times before, but for whatever reason, I can't find more than one post on this subject. The answer is heat flux. Water transmits heat 20 times faster than air, meaning that you would be losing heat faster in water than air. To give you an example of this, [watch this video]( URL_0 ). Both objects are at the same temperature, but the metal in the metal hard drive transfers heat faster so it feels colder than the book.", "100\u00b0F is pretty damned hot for water. Most hot tubs are about that temperature, and take some serious getting used to, and can be dangerous for people in poor health. Temperature and heat are not the same thing. Water has a very high heat capacity, which means it takes a lot of heat energy to raise it's temperature by 1 degree - it's roughly 4x that of air.", "Sit in 100 degree water for an hour and then compare the experience to standing in 100 degree air for an hour.", "100 \u00b0F (38 \u00b0C) water isn't too pleasant if you're immersed in it for a long time. When you take a shower it is warm and pleasant because you don't overheat. A hot tub is nice and cozy because it warms you up. A very weak 100 \u00b0F sauna is also nice and pleasant at first. Edit: [this article]( URL_0 ) is a great source. It mentions that air is thermoneutral (i.e. neither raises nor lowers your body temperature) only up to ~28 degrees (because it can't carry heat as well as water), while water is thermoneutral to 35.5 degrees. So 38 degree water would only be slightly above the limit while 38 degree air would be significantly above it.", "Whether 100\u00b0F air is comfortable or not depends a lot on other circumstances. I've discovered you can be quite comfortable at that temperature as long as (1) the humidity is very low--think desert-like; (2) you are well hydrated--maybe drinking a cool drink; (3) you are not doing any physical work; (4) you are sitting in the shade; (5) there is a light breeze; (6) you are dressed in light, loose clothing. I experienced this in the eastern part of Washington state, east of the Cascades, where the humidity is typically very low in summer."], "text_urls": [["https://www.youtube.com/watch?v=vqDbMEdLiCs"], [], [], ["https://extremephysiolmed.biomedcentral.com/articles/10.1186/2046-7648-3-12"], []], "score": [94, 33, 7, 7, 5]}}, {"q_id": "5quvgg", "category": "Repost", "title": "How does AI (Bots) work in video games?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dd2ajfo", "dd3cah5"], "text": ["AI in games has to have a couple things first; you have to have a designed goal for the AI to do first, and allow it access to stuff to achieve that goal. In a video game this might turn out to be something like a standard fighting game; where the AI is designed to win the match, and is given access to button combination inputs to achieve that. If they want to get a bit into it with difficulty settings, they could change which moves/combos the AI can execute, or how quickly it reacts. In something else like a strategy game, they tend to give the AI certain goals to hit before launching an attack/defending an attack. IE: Have 10 builders/harvesters, 20 attackers, and 2 defensive structures; then issue commands to move attackers across the map toward a target destination. How that all is built is basically programming the AI, although depending on what you want the AI to do, it might range from just mashing buttons to figuring out pathfinding for a giant army. And in plenty of cases, the person programming the AI might let the AI cheat a bit. Now in cases where people argue they want difficulty to mean something more than enemies become bullet sponges, while the player hits like a wet noodle. They want the difficulty increase to mean enemies are smarter too - but that comes at a cost in programming & CPU cycles. Is it really worthit to add in more in-depth AI that checks whether one room is good to hang out in because it has a lot of cover (and having all the programmatic checks and balances to go with that), or use those precious spare moments on the CPU to push out a few more frames per second?", "Ill give you an example. In Dark Souls 1, there are zombie-like enemies with a spear, shield, and medium armor. The enemy is programmed to keep its shield up when you are nearby. From there it can do a few things that are reactions to the players command. Lets say I attack the enemy and hit the shield. My weapon (generally) bounces off and I have a small recover window, then it strikes with its spear. If I don't attack, after a cycle it will attack, which can be parried, blocked, dodged, or I can get hit. Sometimes it changes its cycle to throw you off. Like, the first one you encounter doesnt attack until 5 seconds of waiting, or even waiting over a minute. This teaches patience and the importance of mastering the kick attack, which (when kicking a raised shield) generally puts the enemy into a stun cycle so you can deal the damage you need. It's a more beginner enemy to teach you how to read an enemy's patterns. Also technically bots are VI (virtual intelligence) but nobody uses the term. Doesnt make any sense to me."], "text_urls": [[], []], "score": [23, 3]}}, {"q_id": "5qwc2g", "category": "Repost", "title": "How does hypnotism work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dd2la4b"], "text": ["We are not quite sure, we just know that it works. I am not a professional hypnotist, but I have learned hypnotism, self hypnotism and have been hypnotised. It is the power of suggestion, but we are not quite sure what that is. When hypnotised one comes into a suggestive state. It is my theory that this state is very similar to the state during REM sleep (dreaming) when our brains are going through all the knowledge of the day sorting and storing information. I believe any information given at this time the brain assumes is true because, normally, our brains have processed the information already for storage so has already been \"vetted\" as being true. Just a way of sticking information into the brain that the brain thinks it thought of itself. I have never heard this theory before, or even thought of it, until I just typed it."], "text_urls": [[]], "score": [3]}}, {"q_id": "5qxg3u", "category": "Repost", "title": "How did \"bad words\" become bad? Why can't we use them as just a normal way of expressing your feelings?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dd2us8x"], "text": ["People say angry things sometimes, and they tend to use words for things that are unappealing or imply weakness: *shit, asshole, fuck you, bitch* etc. Those words tend to be tainted by their association with angry speech (in linguistics we call it pejoration), so they become \"bad\" words. The next generation acquires these words with the stigma built in: we as a linguistic community agree that these words should be avoided in polite speech, and you can't just change the way everyone uses words."], "text_urls": [[]], "score": [3]}}, {"q_id": "5qy254", "category": "Repost", "title": "Why do plastic objects (grocery bags, any plastic tubing) turn white when bent or stretched?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dd34han", "dd3cff3", "dd30xpm", "dd3ddng"], "text": ["Bending a clear plastic deforms the material and the small amounts of friction on the inside and outside of the materiel. Heating a polymer changes the crystalline structure of the plastic and way light scatters though the object and thus changes the transparency", "Plastics are made up of long interlocking hydrocarbon chains. When plastic items leave the factory, these hydrocarbon chains are semi-randomly entangled, like a drawer full of computer cables or a well-stirred bowl of spaghetti. This is called an amorphous crystal structure, and it happens to be rather transparent to the human eye. Bending/stretching/slightly heating this amorphous crystal leads to the hydrocarbon chains aligning with one another, meaning the crystal becomes more ordered, more tightly packed (density increases), and harder (work-hardening). This is like the dry spaghetti when they're still in the box: long chains running (mostly) in parallel. This changes the refractive properties of the plastic, making it opaque. Another effect of this process is that the plastic becomes more brittle, which is why if you bend it back and forth a few times, the piece of plastic will break in two along the hardened line you have created.", "I think it more has to do with the unique heat generated at the stress point causing crystallization which has different colour properties.", "Other explanations are good but not really ELI5, so here's mine: Plastic may seem smooth, but if you look through a microscope, it's a little rough, and reflects only certain colours to your eyes, these are the colour we see to begin with. When you bend or stretch it, it becomes smoother, likens polished surface and reflects more light, and if we see all the colours at once, we see white. Extra: the reason it becomes smoother is because plastic is made of lots of little long chains of plastic and when we stretch it, they slide over each other to hold on, but it makes the plastic a little thinner as they all squish up and become smoother."], "text_urls": [[], [], [], []], "score": [95, 95, 10, 7]}}, {"q_id": "5qynhi", "category": "Repost", "title": "Why can't America, adopt some type of healthcare program like Canada or the UK uses?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dd34fpu"], "text": ["It's not that America \"can't\" do that. It'c clearly something that can be done. But the majority of Americans don't *want* to adopt that type of healthcare program, and they've voted for politicians who oppose that type of healthcare."], "text_urls": [[]], "score": [5]}}, {"q_id": "5qyvjr", "category": "Repost", "title": "Why doesnt the earth move from under me while im in the air.", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dd36bsx", "dd36ays"], "text": ["Because of Newton's First Law of Motion: \"In an inertial reference frame, an object either remains at rest or continues to move at a constant velocity, unless acted upon by a force.\" You were moving along with the surface when you jumped or whatever and being in the air doesn't change that.", "It's because you're moving at the same speed. This is the same reason, if you were to flip a coin in an airplane, it wouldn't go flying to the back of the plane. It's moving at the same speed as the plane so, relative to the plane, it's stationary. Likewise, relative to the surface of the Earth, you're stationary."], "text_urls": [[], []], "score": [11, 7]}}, {"q_id": "5qz5cw", "category": "Repost", "title": "How come Americans don't sound like the British even though the British brought the language over?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dd38jjd"], "text": ["OK, actual professor here who teaches and publishes about Old English, Middle English, and historical linguistics (particularly the history of the English language), so I might be able to shed a little light on this topic. Two things to note when we're talking about language change: 1.) Language change is constant, and cannot be stopped. Even languages that spend centuries in isolation (like Hawaiian) will drift. Although contact with other languages can have very real effects on the direction and pace of language change, the change itself will always occur. 2.) Even relatively fast language change (such as what happened in England after the Norman invasion in 1066), is pretty slow. Everyone always feels that they speak the same language as their grandparents, and then when they are older, the same language as their grandchildren, but over the generations the constant changes add up. Let's imagine for a moment that the first human community all spoke the same language -- why then doesn't everyone in the world still speak the same language? It's because of geography ... something that you probably intuitively assume just because you realize that speakers of the same language all tend to live in the same region. So, back to that imaginary first language. If there were only a few hundred humans living in a Garden of Eden, we WOULD all speak the same language with the same accent, and although that language would drift and change, we would all drift and change together, because language is by its nature a communal activity. You speak the language you speak because you were raised in a community that speaks that way. Now then, let's imagine that our first human community grows so large that it separates -- Group A follows and hunts herds living on the east side of a mountain chain, and Group B follows and hunts herds living on the west side. Because they are separated from daily conversation by that mountain chain, the languages of Group A and Group B will both drift, but not necessarily in the same direction. After a few generations, those differences in the way the language is pronounced will become strong enough that we would talk about the Group A accent and the Group B accent. Eventually, those differences will become so strong that they will become to separate languages, and as those communities in turn divide up into geographically-separate communities, and we get different language families over the centuries. So, what about the specific case of English? Well, English starts as a language when speakers of a language we call Proto-Germanic came and settled in Britain, and the geographic separation that the English Channel provided meant that over the centuries the languages drifted off in different directions -- English developing in England, and languages like German, Danish, Swedish, Norwegian, etc developing on the continent. The different Anglo-Saxon kingdoms had very different English accents -- again, because of geographic separation. English speakers way up in Northumbria spoke quite differently than speakers in the southern kingdoms like Wessex. So, fast-forward to the settlement of the New World -- remember that mountain chain that separated our two language groups in my theoretical example? Well, take that and turn the \"mountain chain\" into the Atlantic Ocean. As English-speakers settled the New World, they were no longer in daily spoken communication with people in England, so their accents began to drift off in different directions (add to this the complicating factor that something else was going on in English called the \"Great Vowel Shift,\" but there's no need to get into that). One other little side note -- there has been a lot of discussion about whether American or British English is closer in pronunciation to Middle and Early Modern English. The truth is that American English tends to be much more conservative in pronunciation than British English, so Americans sound more like Early Modern English speakers (such as Shakespeare) than British speakers. I would emphasize, however, that \"closer\" pronunciation doesn't mean \"the same.\" If you'd like to hear a bit for yourself, check this out: URL_0 TL;DR version -- Accents develop over time because communities are not in daily conversation with one another."], "text_urls": [["http://www.youtube.com/watch?v=dWe1b9mjjkM"]], "score": [3]}}, {"q_id": "5r0dcw", "category": "Repost", "title": "How did STD's originate?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dd3hnmz"], "text": ["STD only means it's \"usually\" transmitted via sex. You can get anything through a cut or other means, it's just very unlikely. In the past there was a species of hard working bacteria that was trying to spread on contact.. A few members of the group got inside someone, probably through a skin tear, and started multiplying. Some of them were spread to a partner during sex, and discovered this was a lot more effective technique. As the bacteria evolved over the years, the bacteria that spread through sex became more effective. There were more of them, and the other branch of that bacterial family tree died out. It's the same way any form of life spreads into a new niche. The first individuals to make the journey were lucky (unlucky?) and after that it's just expansion in the newly found niche."], "text_urls": [[]], "score": [7]}}, {"q_id": "5r6flv", "category": "Repost", "title": "What are the implications of losing net neutrality?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dd4zjhh", "dd4zfk6", "dd4tua2", "dd4xvjh", "dd4yz6e", "dd4xxrf", "dd52r0i", "dd4yqu6", "dd50p7z", "dd4y6nd", "dd4zwrd", "dd505wk", "dd51r7r", "dd4yec9", "dd4xx1i", "dd51eot", "dd55owi", "dd4xxsg", "dd52iz4", "dd53m26", "dd52xm2", "dd50c05", "dd596c7", "dd54w05", "dd5tets", "dd52k4p", "dd55hwi", "dd4z3hi", "dd597qu"], "text": ["Imagine if we had a separate privatized road network where you need to pay to drive on it (sort of like a tollway but more of a global subscription). You might think it's suspicious when I suggest it now, but let's say it passes popular opinion because it's _newly built_ road that otherwise wouldn't have been built (therefore not affecting the \"normal\" road network. You might think this is a good plan. It can help ease the congestion of the normal roads since there are now alternatives available for those who can afford it. But in time, you start noticing things: * Speed limits are being lowered on normal roads much more excessively than on paid roads. This could be done to urge/pester people into paying for the subscription. * Newly invented safety measures are implemented on the paid road system first, and will not be fully implemented (if at all) on the normal road network because the budget doesn't allow for it. * Car manufacturers start improving their cars in ways that adhere to paid road standards and become less applicable on the normal road. E.g. would you pay more for a car which has bluetooth connectivity to switch road lights on (paid roads feature) if you do not have a road subscription and there is no bluetooth system on norma roads? No? So that means that a notable subset of new cars that are released are irrelevant for you (or at least unjustifiably expensive). Unless you buy a subscription... * The company you want to find a job at needs someone who starts early, and quickly loses interest in those who do not have the paid road subscription. It's never said explicitly, but it's painfully obvious in the interviewer's posture and interest in the interview. * There is a new company that builds a road that is much safer to drive at high speeds and cheaper to build. However, because this new company is not yet a big player, they might never get picked up because the old road company only just reaches the government's minimum standards for road safety (but, by definition, just over the minimum quality is allowed) * The police is seemingly more helpful to catch reckless drivers on the paid roads. Speed camera's, however, are vastly more frequent on the unpaid roads. Again, this is never explicitly stated as a rule, but rather implied through the results of police actions. * During a particularly brutal election year, the current Rep/Dem government adjust the roads. Lanes are closed, speed limits are lowered, and it will take you hours to get to your destination. \"Coincidentally\", the roads that are affected are the roads that lead towards the Dem/Rep conventions (the opposite party). * (edit: added by /u/FrogLeatherShoes, elaborated by me) Car manufacturers have to pay licensing fees to the road people to make the car compliant, preventing any new car manufacturers from entering the market. BMW can pay the $10,000 licensing fee per car easily. But a new startup will not be able to, because they can't run their business when everything they sell will have to be $10,000 more expensive to cover the licensing cost _that nets their own company not a single benefit_. There are many ways in which this system can be manipulated into urging people to pay for the subscription. Doesn't matter whether it's through making the unsubscribed version more shit (or improving it less than the paid version), preventing previously unknown companies from making the next breakthrough, or causing a divide between the subscribed and unsubscribed people (economically, employment, ...). And once we get to a point where practically everyone has the road subscription, then _no one_ gets the benefit from having a subscription anymore (since the paid roads are just as congested because everyone can drive anywhere again) **but we are all still paying for the subscription nonetheless**. ----------- This problem, and many like it, can be summed up like this: * We make a separate option that's better, but more expensive. The main argument for having it is exclusivity (e.g. uncongested roads) which makes things nicer for those who can afford it. * Big business, however, is in it for the money. They are constantly trying to get more people to partake in the system, because more customers means more money. * As the percentage of people paying the extra increases, the company's profits increase. However, the original benefit (exclusivity and separation) moves out of sight because the majority of people are now all exclusive. * Once big business has completed its goal and convinced everyone to pay the extra, the exclusivity is completely gone. People have paid for years for something that has slowly slipped from them, and they didn't even realize it. Worse still, they can't even opt out of paying extra now, because everyone is doing it and it is now expected of you. Not paying the extra makes you the poor outcast. * Suddenly, everyone is locked in a system where they are all paying more, no one is getting any benefit from it anymore, but no one wants to leave out of fear for being ostracized or simply getting the short end of the stick at a point where they need it most. ------- Edit /u/manfromporlock made a [comic]( URL_0 ) about pretty much the same analogy.", "Remember when Facebook came around and we all switched from Myspace? Now imagine Myspace saw this threat and was able to throw around their (at the time) considerable clout and money, and ensure that anyone accessing Facebook would do so at a significantly slower speed than Myspace. Sure would make the switch less compelling, wouldn't it? In short, net neutrality ~~combats~~ protects \"free trade\" of an open internet. We choose the service we like / are better, not the one with enough money to ensure they're fastest. Imgur is en vogue, Photobucket is not. Gmail is, AOL is not. Google is, askJeeves is not. Reddit is, SomethingAwful is not. You get the idea. We evolve. Net neutrality preserves our ability for a nobody to make a website that challenges the service of a somebody.", "1. Companies and governments can block certain websites they see against their worldview or interests. 2. Companies can make certain websites very slow 3. Big companies like Facebook and Google will destroy competition creating monopoly 4. Consumer issues will not be addressed. 5. Censorship of unpresedented heights 6. Internet as a whole will collapse as few people comtrol what is spread and shared around 7. Will impact economic growth as internet censorship affects new startups.", "[Here]( URL_0 ) is a good representation of what it might look like if net neutrality were abolished. Basically, Internet Providers could charge you for accessing different websites the same way TV Providers currently charge you for accessing different channels.", "You buy a microwave from Corp A. When you microwave a burrito purchased from Corp A or one of their partners, it is free. When you microwave a burrito purchased anywhere else, it costs you an additional $1 per burrito.", "One of the many implications is the possible appearance of so called 'fast lanes'. Without net neutrality, ISPs (Internet Service Providers) could start prioritizing traffic however they desire. They could slow down traffic to website they do not like while providing fast traffic to their 'partners'. This would like lead to deals where website providers would have to pay the ISPs for them to provide fast access to the site. While this would not be much of an issue for large companies like Google or Facebook, it would essentially shut out new competition as they might not be able to afford what is essentially extortion money. And you as a consumer would only get fast access to websites that your ISP want you to go to, essentially leading into corporate censorship.", "Basically all big corporations that sell internet connectivity also sell cable tv. They also have their own streaming services that are not as good as netflix, primevideo or hbo. And by law these corporations must treat all traffic equally. In contrast cable tv is a huge dated mess with total lack of innovation and rising costs and amount of commercials. These big players want you to use cable. They want you to think cable is what you want. By adding bandwidth caps and making online video services worse they artificially make cable look better. The thing is that when the equal traffic limitation is changed it allows the big corporations to fully control the internet as a market. They can choose who gets in and who gets out. And I'm not talking about people who use the internet. I'm talking about big and small businesses that use internet. This means the internet selling corporations can double dip. Or actually tripple dip. They can ask \"connection money\" from other businesses who use the internet. Amazon, google, hbo, netflix, reddit, foxnews, nascar... If you have a website you need to pay for it to be available to people. Then they can ask you to pay twice. First for your internet connection and then to get access to some other sites. You may be thinking this sounds right? Surely they should not be forced to offer that service for the other corporations for free, right? The thing is it is not free. YOU pay for it. You pay for your access to google, netflix or whatever when you pay for your monthly fees. You pay it through the taxes because these companies have been given billions of money to build and update the infrastructure. Which they have not done. But they want more. So those other businesses? Google and netflix buy their own server hardware so they can be connected by people like us who buy internet connections from the big internet providers like comcast, att, timewarner, verizon and such. It is not that netflix or such are being unreasonable by just trying to force comcast to play along. Netflix have even offered to pay and install their servers in comcast's server locations but comcast will not allow it. They want netflix to give them money while accepting worse terms. So what happens is that tripple dipping I mentioned earlier. What it does it stagnates the market. Because the only way to compete is to own the network and essentially own the customers. Being a newcomer like netflix is literally impossible. Not only do you need to take a gigantic financial risk to pay for the connection fees, server hardware and content creation costs but you need to compete with one hand tied behind your back. Your customers get slower speeds, worse connectivity and have to worry about datacaps. All the while the comcast's own service can utilize the full bandwitdth and users don't need to worry about datacaps. At least in the beginning. It is impossible to compete against that. And it is a huge untapped goldpot for the comcasts. How much can you ask from google, microsoft, sony, facebook etc for them to be accessible through internet? They can not afford to not pay! The profits are rediculous. All the same time you as a customer can be asked to pay more. And it doesn't even end there. These comcasts want to be the big players. They don't like facebook and google selling ads. They want to track you and be the ad server facebook and google can only dream of being. You can try to avoid services like google and facebook if you don't like being tracked. But when it is your internet connection that is tracking you then the only way to opt out is to not use internet at all.", "Sorry! That's not available on your current Internet package! Upgrade your plan and add great sites like Reddit\u2122 today!", "I wrote a comic explaining it here: URL_0 . TL;DR: Losing net neutrality lets your ISP hold your ability to connect to any given website hostage, for their profit. That's from 2014, though, so I didn't go too deep into the political implications of that. Which are: It doesn't have to be for profit. It can be for political reasons--because they, or politicians who are leaning on them, don't want you reading or watching specific things on the internet.", "Can vouch that Chinese internet sucks, living here for 3 years. Anything anti-government (or that is against the government worldview) is blocked or deleted, from websites to individual posts and comments. Imagine all those videos of discrimination against blacks by police being removed immediately, for example. Or if trump is in charge in the u.s., anything anti-trump. Certain sites or pages made intentionally slow to the point of you not wanting to use them. Shitty websites have a monopoly because they're government-supported. No porn. Etc.", "Net neutrality came about a long time ago, actually. Back in the early telephone days in the 1800's, you'd see dozens of telephone lines hanging outside your apartment building, from different companies. This was a safety hazard, so government said \"Only one of you is allowed, but you have to share that line with everyone equally\" and so common carrier was born. This remains in effect to this day, because ISPs are monopolies, and they have to play by monopoly rules saying they have to share their line to your house. Otherwise we'd be back to dozens of different lines from different companies attached to your house. Common carrier means the people connected to your house can't interfere with the actual communications - they only sell the physical line. This is net neutrality. Without net-neutrality, Comcast, for example, can now censor your communications if you use their network. Right now you can criticize Comcast, but without net neutrality, they can monitor your communications and ban you for criticizing them. Comcast can ban you for any reason, actually, even if they just don't like you. You will have no right to their network. You will most likely have to pay for sites that you now access for free. Those sites that rely on ads are now going to have their ads blocked by default on Comcast's network. They will have to pay Comcast to allow you to use their network to reach you. If they don't, their data rates will be slowed down, if not completely banned.", "The \"great firewall of china\" is what happens to \"the free world\" without net neutrality. You just replace China with USA. In China Google = Beidu, YouTube = Youku, Facebook = WeChat etc. Why? Because why allow foreign companies to make money, when national companies can. Many foreign services are NOT blocked or illegal - the speed is just SO bad that it just doesn't work! That Swedish Spotify? Could be slow shit compared to \"random commercial interest\".", "It's important to remember that net neutrality in the United States only happened in 2015. So it's not like there was a massive problem that it fixed or the Internet sucked before it. That said, net neutrality came right before problems really started to occur. One of the main things that happened to create outrage was that Netflix accused Comcast, with plenty of evidence, that netflix data was being slowed down. This wasn't to charge the customer more, but for Comcast to strong arm netflix into peering agreements, and this tactic actually worked. Data is charged on both sides. You as a consumer want to access Netflix. But Comcast needs to provide access to Netflix if they're your isp. While many are correct that the absence of NN would allow Comcast to charge you more to access Netflix, they could also charge Netflix more money directly to still deliver its customers. This was the tactic previously taken before NN. To use the road analog every one else is using, instead of charging a toll to use the road, they can also charge the businesses along the road more money to allow their customers on that road. Beat Buy pays more than Walmart to use the road, so when you get on the road, you can drive faster to best buy but have to use the slow lane to get to Walmart. As a consumer, it doesn't cost you more directly, but it does influence your decision. All in all, net neutrality ensures all traffic on the Internet is created equal. It doesn't matter if you're watching netflix or pornhub, they will be delivered at the same speeds and without an additional package from your isp.", "I'm doubtful that ISP would completely block certain websites from being accessed, as there would be enormous outcry from the public, but there is a very real danger of sites like Facebook and Netflix loading far quicker than websites owned by people who can't afford to pay the ISPs huge sums of money.", "Net neutrality is a basic principle of the internet free and equal ability for everyone. If you register URL_0 you can technically compete with google, getting rid of net neutrality is eroding this whilst making money solely for net providers", "A few giant conglomerates, some of the most hated companies in America, would have complete control over how you access the internet. They could exert that control in subtle ways. Oh, is Netflix slow and choppy? (because we made it that way) Are you about to hit your video streaming data cap? - just sign up for Comcast XFinity instead! It'll always be unlimited and the fastest because there's a direct pipeline between our asshole and your face! They could exert that controls in not so subtle ways. Walmart paid Comcast so that you could no longer get on URL_0 , and in fact, trying to go to URL_0 redirects you to URL_1 . Or Microsoft pays Comcast to ban Playstation network traffic. They could start trying to make up for their losing cable business by stratifying and charging for the internet in the same way. Pay an extra $10 a month for the social media tier, so you get unlimited access to facebook, twitter, etc. Pay $10 a month for a gaming tier, so you can access steam, xbox live, etc. This could also work on the back end, too. They could start demanding that Netflix, amazon, etc. pay them to get their website accessible from their network. This would ultimately raise costs for consumers too. They could start to control what information you could see at all. They could literally block sites they decide are unfavorable to them and redirect to sites they view as favorable to them. They could censor or redirect the internet in whatever way they wanted. Access to information today is as great a need to people as having electricity or indoor plumbing was decades ago. How you interact with the world and what you know is shaped by your access to the internet. Would you be comfortable giving complete control over that access to a few telecom companies that we already know are hostile to consumers and which most people despise? And for almost no benefit to the consumer. It hurts the consumer, it hurts every other business other than the telecom companies, and the only reason anyone is even thinking about it is because the telecom companies are the biggest ~~source of bribes~~ lobbying industry there is. Network neutrality has been the policy of the internet since it's inception, and it's largely why it has been the greatest market for the free exchange of products, services, information, discussion, and ideas that has ever existed.", "There is a lot of fear mongering and Chicken Little in this thread. Net neutrality ensures all bits are treated equally, which sounds great in principle, but would have very detrimental unintended consequences. The easiest example to think about is being on a Skype call vs sending a large file over email. On the Skype call, even the slightest lag time is very distracting and disruptive to the call. But if your email takes an extra 10 seconds to get to its intended destination, you probably don't give a shit. As bandwidth needs continue to increase at a 50% CAGR, network congestion will increase. Yes, ISPs and others are constantly upgrading their network, but there are bound to be situations where nodes get overly congested. To combat that, rules can be set to prioritize traffic like Skype calls or gaming, and deprioritize your neighbor's email featuring every stupid picture taken on their family vacation. That is an oversimplified, but still accurate and relevant, explanation of why net neutrality isn't the right solution. The \"ISPs will charge for privilege\" fears listed here can be combatted through other ways the FCC can implement. Net neutrality is just too broad of a ruling to counteract those few particular fears.", "Surcharges and packages based on what websites or content you want to access. These may be negotiated between the carrier and the content provider or between the carrier and the consumer, but either way the consumer will pay for them.", "This was addressed in a pretty ELI5 way by The Oatmeal: URL_0 Also like this take as an explanation: URL_1", "Net neutrality is a fancy word meaning government control. The FCC has been upset about the fact they dont have control over the internet since it was invented. Thats all this is. Its a very bad thing. The funny thing is that if the world knew it would threaten their free internet porn, it wouldn't pass in a million years.", "the structure of the Internet itself is to be node-agnostic, i.e. traffic can flow through any available set of routers and computers to facilitate communication. DARPA did this on purpose to make the network highly robust, and neutrality is a natural consequence. Non-neutrality therefore defeats the original robustness intent. Let's just say that when the military or the government needs to use the Internet, that they suddenly won't find themselves scrambling to pay unexpected fees first. \"I gotta communicate with my battalion!\" \"Oh, military data! We have a special $299.95 per hour rate! Because obviously you'll want the best bandwidth for that right hee hee.\"", "Imagine Verizon starting their own streaming service (assuming they don't already have one, I'm not in the US) that competes with Netflix. Let's say you're paying for a 50 Mbit connection from them, but still, for some inexplicable reason, Netflix is always slow and buffering when you want to watch Ultra HD content. Verizon's Netflix competitor, however, is always flawless. Without net neutrality, there's nothing preventing Verizon to configure their system like that. Verizon could demand that either the customer paid extra to get full speed to Netflix, or they could demand that Netflix paid them extra if they wanted Verizon customers to get a good experience, or (most likely) both. Now, Netflix is big enough and rich enough to be able to deal with this sort of extortion, so they'll stay in business. A new competitor on the streaming video market, however, might not be able to afford this, and a significant portion of their potential customers would stay away from them because they would always get poor quality video from them, which could very well lead to this new competitor going out of business. Essentially, it opens up the doors to segment the internet connection a lot. Companies that are in a near-monopoly situation in a region could demand extra money for every online service that competed with something they were offering themselves, or just demand extra money for anything they think is so important for their customers that a significant portion would pay for it. To use an analogy, it would be like the bus driver asking you what you were planning on doing downtown. If you said \"watch a movie\", the ride would cost you 3 bucks, but if you said \"buy a game\" the price would be 5 bucks. After all, the game is going to entertain you for ten times as long as the movie would, so that's a fair deal, right? Of course, it wouldn't be as easy to lie about what you were going to do to an ISP.", "Pay walls everywhere. Websites being like tv stations so unless you pay for it you dont get it. So if you wanna look something up but don't wanna pay $50 a month for wikipedia then it sucks to be you. And more over these costs would be on the consumers and the website owners. Whose very existance is already profiting the ISP's. So it would just be giving more money to some of the wealthiest companies in the world in a market they already have huge profit margins in.", "None of the top answers feel eli5-worthy, so I'll give it a shot. Let's say you have an electrical outlet in your room. You pay for electricity monthly, so you expect that when you plug in something like a lamp or a toaster, it's going to work. But now imagine that on top of what the electrical company charges you, they're also charging the manufacturers of each gadget for the privilege of working on electricity. So Big Toast, the world's largest toaster company, pays the electrical company millions, and passes that cost onto you, by increasing the price of their toasters. When you buy a Big Toast toaster, it immediately works, and you get delicious toasty bread within 3 minutes. But Small Toast just doesn't have the money to pay the electrical company, so it doesn't do it. And what happens when you buy this toaster? It hardly works, because it barely gets any electricity from plugging it to the wall. It's really slow to toast, and you need to wait 20 minutes to get a golden piece of bread. Small Toast didn't pay the electrical company its extortion fee, and because of that, you (who pays the electrical company every month) aren't able to use the electricity as you see fit. This is what net neutrality prevents. Cable companies can censor your internet on a whim. They can prioritize companies who pay them, or they can block access to sites they just don't like--- such as filesharing sites that will use up a lot of band-with, or porn sites they find morally reprehensible. Without net neutrality, there's no limits to what they can or can't do. And because all cable companies are doing it, switching to a competitor won't help. There's also nothing stopping cable companies from prioritizing their own streaming sites, and preventing you from connecting to their competition--- which would be analogous to your electrical company forcing you to buy their own branded toaster.", "I've had good luck with a similar, more simplified analogy: Image if people could pay to have more green traffic lights. Instead of each car waiting their turn at intersections, drivers who pay a fee could have the light always turn green for them while non-paying drivers have to wait extra.", "My question is, did we see any examples of these problems pre-net neutrality that didn't stand the test of capitalism? Sure, Comcast I think tried with Netflix, but ultimately backed down. Now instead, positive anti-net neutrality line what T-Mobile (free YouTube data and most music services) is doing may soon be classified as illegal.", "Tell me if Im wrong please. With Net neutrality it puts the power into the hands of the FCC? If that is true that means that the govt ends up having the power of the net and can change the rules when they want. Also is this not happening today? In the sense that net neutrality is suppose to allow for a free open internet where companies dont dictate traffic. But yet we see companies giving free data away for their sister companies or other companies that buy into their service. Such as ATT with DirectTV and Tmobile with there stream unlimited plans. Forgive me if im wrong.", "There are two major concerns here, and they are not what most people think they are. The first problem is that many of the largest US companies, and certainly the fastest growing US companies, are almost exclusively in the Internet business. Google, Facebook, Amazon, Microsoft, Netflix, LinkedIn, Groupon, TripAdvisor, Twitter, Spotify and even Apple all have business models that partially or entirely depend on net neutrality. One of the remaining markets where US companies can actually still successfully compete, will be devastated. The second and perhaps more disturbing, it that it makes the US infrastructure more vulnerable to attacks from terrorist organisations, foreign nations and natural disasters. If content on the Internet is limited to a certain providers network, when the next feces to fan intersection happens, and all lines are busy due to artificially low bandwidth, how is that going to ruin your day?", "Right now when you pay for internet, your internet provider is required by law to treat any sites you might go to equally. Your ISP treats Hulu and Netflix equally. But Comcast owns a large share in Hulu, and Netflix is there competitor. So if Comcast if your ISP, they don't want to treat Netflix equally, they want to make Hulu run faster. They want to give more bandwidth to Hulu. If we lose net neutrality, your internet provider gets the OPTION to give preferential treatment to some web services over others. Netflix might slow down while Hulu speeds up. Or Netflix might never get enough bandwidth to run in HD. Your internet provider also gets the OPTION to charge you more for some services. And they could insist that Netflix pay them in order to receive the same service they had before. So Net Neutrality is bad for internet service providers (because they have fewer options) and is good for consumers and companies that are dependent on the internet because it protects them. Internet service provider tend to be legalized monopolies because the government wants to discouraging running 3 different cables through high population areas and zero cables to rural areas. instead of 3 options for cities, and zero options for rural, they want at least 1 option for everyone. In exchange for being a legal monopoly, they have traditional accepted this high level of regulation. Customer cannot leave Comcast for another ISP, so Comcast isn't allowed to screw them over."], "text_urls": [["http://economixcomix.com/home/net-neutrality/"], [], [], ["http://theamericangenius.com/wp-content/uploads/2014/01/net-neutrality.jpg"], [], [], [], [], ["http://economixcomix.com/home/net-neutrality"], [], [], [], [], [], ["www.sbskbeksks.com"], ["amazon.com", "Walmart.com"], [], [], ["http://theoatmeal.com/blog/net_neutrality", "https://www.youtube.com/watch?v=rz4Ej3IVefo"], [], [], [], [], [], [], [], [], [], []], "score": [8102, 1546, 1421, 473, 174, 171, 170, 117, 63, 51, 38, 21, 18, 14, 12, 12, 9, 6, 5, 5, 5, 5, 4, 4, 3, 3, 3, 3, 3]}}, {"q_id": "5r6s74", "category": "Repost", "title": "Why are there so many programming languages?", "title_urls": {"url": []}, "selftext": "I'm beginning to learn how to code, and know some basic javascript, python and c++. The question I have is why there are so many programming languages? I haven't come across anything that I can do in python that I can't do in javascript or c++, and I've heard that c++ is generally a faster and therefore more popular language for applications, but there are some things that c can do that c++ can't etc., but I still don't understand why there are so many? Why do java, python, ruby, ruby rails, c, c#, c++ etc all need to coexist? Why can't one language cover all bases?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dd50uzj", "dd4wfdf", "dd4wpey", "dd4ye15"], "text": ["Practically speaking, all programming languages make trade-offs, and different programming languages prioritize some things, like performance, control, readability, and convenience, over others. For example, C++ prioritizes runtime performance, but must be compiled ahead of time and requires more lower level understanding. Python is generally a lot slower, but abstracts away certain kinds of complexity (such as memory management) and is generally easier and faster to develop. A lot like human languages, different programming languages also encourage different ways of thinking. Almost all the languages you mentioned are primarily designed to support what is called \"imperative\" programming. If you want to see something really different, look up a language that encourages \"functional\" programming, such as Clojure, Haskell, or Scheme.", "Because who would own that language? Who knows best? And what if you want to do things differently? There are - for some languages - more technical reasons since not all languages will work in every situation. (Programming for a web environment is different from a windows environment, which is different from a unix environment, etc) But basically the same reason you have 20 kinds of peanut butter : Diversity, choice and i know better than the rest :)", "Since programming languages were first invented a lot of new ideas and new ways to use them were created. You have different ideas about how it is easiest or best to write a program and thus end up with languages that are imperative or object oriented instead. In addition to that you have programming languages that are built for certain purposes. For example PHP while it can and is used as a general purpose programming language was originally conceived especially as a language that would work well for helping creating dynamic websites and has many tools for connecting to databases and working with html built in. That is nothing you couldn't do in most other languages, but it would be a lot harder in many of them. Other languages differ in how they are used. You have languages that are compiled into binaries and others meant to be used in scripts that are interpreted on the fly any times they are run and hybrids between the two like Java. You might say that you have some many different languages because you will always need to use the right tool for the right job, but the thing with programming languages is that you can achieve the desired result with almost all of them if you really try. A lot of it comes down to personal preferences and fashion fads in the end.", "Different programming languages do different things, there are many, many ecosystems that require a different touch when it comes to how they're programmed. To give you an idea of the different applications, consider a hospital. Hospitals have specialised equipment, and can therefore have one 'technological ecosystem'. The hospital requires that the software written for their ecosystem be robust, to the point and able to process a large amount of data. Writing programs like this in JavaScript is incredibly difficult; JavaScript cannot *itself* communicate with low-level computer processes, it needs some sort of executor (Chrome, for instance.) Java would be a better bet, Java is a robust language that can execute low level tasks, but it still requires a Java Virtual Machine to be running on the hospital machines. This is where .Net would come into its own; able to communicate with low-level hardware, and with built in UI drawing, memory management, strict type-safety, and security. For a business? The backend would most likely be Java, but try creating a front-end in pure Java! (As an aside, I like Java FX, but it isn't a competitor to a JS/HTML front end) Java is free, quick, supported everywhere, and has a huge library of functions to integrate with other software services (Google APIs, Databases ect.) Netflix uses Java to deliver its service, using a Spring Web-MVC framework, but what you see when you log in is all JavaScript and HTML. The \"Which language is best?\" argument pops up quite a lot, and it gets to a point when you're working as a software developer where your reply is \"Well, what are you trying to achieve?\" and provide an answer with valid reasoning. When you start programming the languages seem to all do the same thing: print \"Hello World\", find the answer to this problem, reverse this string, but when you start actually working on a project you will see that development is so far beyond these simple tasks. For instance, I'm using Groovy to write automation tools for companies. Why Groovy? Groovy is an extension of Java, but what is special about it is it can run as a 'script', rather than being built into a .jar like Java. This means that a developer can use Java, an incredibly powerful language, and integrate it into other platforms in small chunks. Even popular applications like Jenkins allow you to write pipelines in Groovy, it's a fantastic language. Anyway, to learn the difference between languages, you have to ask! That's the best way to get the knowledge and become a more rounded developer. I also recommend picking up an object oriented language like Java or C++, it's incredibly useful and has lots of transferable skills when you move on to other languages. Let me know if you'd like anything explained further, I'm happy to expand on any languages I know about."], "text_urls": [[], [], [], []], "score": [6, 5, 4, 3]}}, {"q_id": "5ratwq", "category": "Repost", "title": "Why hasn't the world try to create a unified global currency?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dd5r3rd"], "text": ["Because global economics is extremely complicated and volatile for such a thing. Just look at the income/cost disparity here in the USA alone. Now try to apply that all over the world and try to get people to agree upon which units of the same currency are worth which items/functions. It would be a mess. It's hard enough dealing with our currency translations. Now, imagine every country on this planet all agreeing, all the time, to what the values of each unit of currency were."], "text_urls": [[]], "score": [3]}}, {"q_id": "73kad3", "category": "Repost", "title": "Why do mirrors only reverse images horizontally?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dnqy5x2", "dnqy5qy", "dnqy5p5", "dnr08ql"], "text": ["They actually don't flip horizontally. They flip front-to-back. It just *seems* to flip left and right because in order for you to face in the opposite direction, you imagine rotating around 180 degrees. But since the image's left side reacts to your left side's motion, it appears to be the left side (from your point of view) of a rotated person (since they appear to be facing you), which you know to be that person's right hand.", "It doesn't actually reverse images horizontally, it reverses them front-to-back. However, when you see the image of a person facing you, you expect it to look like you would if you stepped forward and turned around. That rotation has the effect of flipping front-to-back and left-to-right, while leaving top and bottom alone. So when you see an image that is only flipped front-to-back, you think that the mirror started with the rotated image that you expected to see and then flipped it left-to-right.", "They don't. They flip front to back. Stand in front of a mirror. Point left. Reflection points in the same direction. Point up. Reflection points the same way. Point at your reflection...", "Imagine yourself lying on your side, looking at a mirror. Are you flipped left to right relative to yourself, or left to right relative to the room? It depends on how you imagine yourself turning to get to that position. If you roll over, then your left hand would be where the image of the right hand is. But if you turn around a vertical axis, your head is where the image of the feet are. Likewise, when standing in front of a mirror, you could imagine yourself flipping head over heels and your inverted top to bottom."], "text_urls": [[], [], [], []], "score": [10, 10, 8, 3]}}, {"q_id": "73l9je", "category": "Repost", "title": "If inside my house is 60\u00b0 in the summer it feels nice. If it's 60\u00b0 in the winter it feels cold. Why?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dnr82ac", "dnr63hd", "dnr6hg1", "dnr5yi2", "dnr759g", "dnr66ot", "dnrcw0x", "dnr4qs0", "dnr5k85", "dnr7adg", "dnr6n03"], "text": ["The real answer is relative humidity (moisture level of air), not all 60 degree temperature is equal, you are constantly losing moisture through your skin, and for that moisture to boil off (evapourate) it saps energy from you, cooling you down. In the summer, there is a higher relative humidity in the air, slowing this process, if you heat yourself up enough, you will noticeably sweat as this moisture is having a slow evaporation process In the winter relative humidity is drastically lower, causing this process to almost immediately draw moisture off of your skin cooling you rapidly, therefore making you colder, even though the air is still 60 degrees. This is more common in older homes that don't have a vapour barrier, if you install a humidifier, (or even have a hot shower or two without running the fan to raise levels) you may see noticeable improvements.", "It\u2019s due to heat transfer from radiation. There are three types of heat transfer: convection, conduction, and radiation. Convection and conduction both transfer heat linearly with changes in temperature, but radiation\u2019s heat transfer is to the fourth power of temperature. So basically if it\u2019s 90 degrees out and you have a window pane, the inside of the glass may be 85 degrees, and it is radiating heat towards your body at a constant rate. Drop the outside temperature to 60 outside, and the drop of radiation heat transfer drops an absolutely massive amount. Remember, it\u2019s not temperature you feel but the amount of energy that\u2019s being transferred to your body ( think a 60 degree pool vs 60 degree air) Edit: typo", "Neat, I know this one. There are three basic forms of heat transfer, convective (transfered through air) conductive (transferred through solid material contact) and radiative (does not need a medium to travel). If you're standing in the middle of the room, the heat transfer rate between the air and yourself is the same in both 60 degrees scenarios, however you're losing large amounts of heat to the cold exterior walls/windows through radiative heat transfer in the winter, making you feel relatively colder.", "It is the opposite for anyone I've ever talked to. 72 indoors feels cold in the summer and 72 indoors feels hot in the winter.", "ITT, Americans taking about temperatures casually while the rest of the world wonders how anyone could find 60\u00baC *cold*", "For the same reason it feels different in winter when it's sunny or when it's cloudy even if the actual temperature is the same and no wind is blowing. The surface temperature of walls, windows, floor and roof is not the same. You feel the difference through thermal radiation.", "As a licensed professional engineer in HVAC, there are a variety of factors that have mostly been touched on already.: **Radiation:** You radiate heat to everything around you. When the temperature of everything around you decreases (such as the walls and windows would in the winter) you'll lose more heat. **Convection:** When the walls and windows are colder than the room, the air near them will cool, and this cold air will fall to the ground and move around your feet (Called a draft). In the summer, warm air goes up to the ceiling and unless you're 9ft tall, you won't feel that as much. **Humidity:** In the winter the air is often more dry in your house because the outside air can't hold as much much moisture. The sweat that you're always producing on some level will evaporate more quickly with low humidity, making you feel colder. In general, temperatures don't make us comfortable. A certain level of **heat transfer** makes us comfortable. There's actually a standard in our industry: ASHRAE standard 55 for thermal comfort that goes into great detail on this.", "Your question's flawed as staying inside your house being 60 degrees in any season will not feel comfortable for long. Stay in there without anything but enough thin clothes for decency and you'll end up being cold pretty soon. But this isn't so much a Physics question as a biology one. The reason it's immediately comfortable is due to a combination of humidity levels and your body being used to the other extreme. If you've been outside in a \"true\" subzero winter where you're actually cold due to not enough insulated clothing and your body has chilled down, sixty degrees coming in feels GREAT because it's so much warmer than what you've been used to. On the opposite side of the spectrum, coming inside after being outside in sweltering humid temperatures where your body couldn't evaporate sweat (its primary mechanism for self-controlled cooling) because the air was already saturated so no cooling evaporative effect could occur, that sixty degree temperature also feels great. The conditioned air in your house, which has MUCH lower humidity, helps evaporate your built up sweat, and suddenly you're almost instantly cooler and more comfortable... for a while, until that sixty degrees starts becoming chilly. And part of how you feel is what you're used to at that time of year. If a northern Canadian goes to Florida in mid-winter, they can delightedly amble around outside in a t-shirt (as long as they don't get sunburned) while the locals complain about how frigid it is. But they'll shrivel up if the temp's 85 the next day while the locals are quite comfortable.", "I'm curious if you really have your AC set to 60. Your electric bills must be insane. If you really do, one factor is probably the relative humidity. The second is how the thermostat knows when to turn on. Usually there are a few degrees it will drift above and below the set temp before turning on or off. So in the winter it would probably get below 60 much more often than in the summer, especially in rooms away from the thermostat this would be even more exagerated.", "I think it's expectations. Just like how if you drink room temp coffee it seems cold but room temp soda seems hot, even though they are the same temperature.", "It's hard to say for sure without more information but it's only 60 at the thermostat. There's going to be a gradient towards the outside walls and the outside temperature. Imagine a drafty house with 60 at the thermostat. In the summer it will be warmer closer to the window but in the winter it will colder closer to the window. If you are actually comfortable at 70 and you usual sit closer to the window you might need the thermostat at 80 in the winter."], "text_urls": [[], [], [], [], [], [], [], [], [], [], []], "score": [1148, 793, 116, 62, 58, 53, 45, 30, 26, 14, 12]}}, {"q_id": "73lfhn", "category": "Repost", "title": "What is happening when your foot/other body part falls asleep?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dnr5no2"], "text": ["Restricted blood flow to nerves or putting pressure on the nerve itself messes with the signal that can be transmitted along the length of the nerve. You perceive that \"messing with the signal\" as the limb going to sleep. You're not damaging anything in the short term, though. I've read that from the time a foot or leg goes to sleep, you're still 2-3 hours away from damage to the cells involved."], "text_urls": [[]], "score": [3]}}, {"q_id": "73mbwa", "category": "Repost", "title": "How do broadcasting companies know how many people tune in to their radio shows or tv shows?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dnrfgpq"], "text": ["They send out surveys through companies like Nielsen. You can volunteer to participate by filling out a form listing what shows you watched in a given week. They can also do it technologically. In the old days, volunteers would be given \"set meters\", which would record what channel the household was watching, and at what times. Today this data can be scraped from digital cable boxes."], "text_urls": [[]], "score": [3]}}, {"q_id": "73mihp", "category": "Repost", "title": "Why is the keyboard arranged in the way it is and why is QWERTY the most popular arrangement?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dnrdi9y"], "text": ["QWERTY is a hold-over from the days of typewriting. The common misconception is that it's designed to slow a person down, which it isn't. The fastest QWERTY speeds are on par with other keyboard layouts by and large. What QWERTY does is attempt to split up common letter patterns on different sides of the keyboard. Back when keypresses actually caused a metal arm to swing up and punch the ink onto the page, the mechanism could get jammed up if nearby keys are pressed at the same time. QWERTY helps keep more of your keypresses coming from alternating hands and letters that aren't right next to each other on the typewriter mechanism."], "text_urls": [[]], "score": [3]}}, {"q_id": "73nws1", "category": "Repost", "title": "What would happen if a US State tried to secede today?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dnrq8pp", "dnrrhn8", "dnrqyvy", "dnrrims"], "text": ["Last time it was tried, we had a war that killed a million Americans. There's no reason to think it would go down any differently this time. There's no peaceful way for it to go down in current law. While, technically, anything is possible if you can pass an amendment, it's highly unlikely that you could get 2/3 of the states to support one allowing a state to leave the union.", "There's no real way to answer this question in the abstract: it would depend entirely on what state wanted to secede, why they wanted to, and how people in that state and the rest of the country felt about it. The outcomes could range from anything between an amicable dissolution to a second civil war.", "The United States government views secession as attempted theft of federal land and property. It wouldn't be allowed. I'd imagine they would try to quell something like that first with federal law enforcement, leaving military intervention as a last resort. But they absolutely would stamp in out militarily if that became necessary. Tl;dr ain't gonna happen.", "There is no legal process for succession. No state can do it. If a Governor attempted to use the national guard to establish some kind of independant nation regardless of legal opinion, it would likely be interpreted as an attempted coup d'tat"], "text_urls": [[], [], [], []], "score": [10, 5, 5, 4]}}, {"q_id": "73r3w0", "category": "Repost", "title": "Why is Semen easier to clean with Cold water instead of Hot water?", "title_urls": {"url": []}, "selftext": "Isnt almost every other sticky material easier to clean with Hot Water, including Cyanoacrylate?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dnsgv2o", "dnsnhky"], "text": ["Semen is full of proteins. When they get hot, they denature and become sticky. It's like scrambling an egg.", "I've actually learned about this in anatomy courses (not specifically the cleaning it off surfaces part though) so here's a bit more information off the top of my head. Without getting too detailed, there are a lot of things in semen. Within the first few minutes or so, there are proteins that will coagulate and make it sticky. Heat makes microscopic things move faster, so something warm will speed up the process. There are also enzymes that will start to break down the proteins, making the semen more liquid again after another 10 minutes or so. There doesn't seem to be a reason for it as far as we know, and I can't confirm it because I've never left semen around long enough to find out. I think you'll find that if exposed to air it will start to dry up anyway, which kinda negates the fact that it gets less sticky."], "text_urls": [[], []], "score": [14713, 768]}}, {"q_id": "73rhl1", "category": "Repost", "title": "If camera lenses are circular, why do are pictures come out as a rectangle?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dnsjply", "dnsjji2", "dnsjxjq", "dnsjik0", "dnsk64p"], "text": ["Lenses are round because they're easier to manufacture that way and it means they can be rotated to for zoom without that affecting how the lens works. ~~It's also easier to make a shutter that works in a circle.~~ This just gets the light in and focuses it. The light falls onto a light sensitive detector or film which is rectangular. In both cases this is because that's the preferred format for pictures...but also because it's easier to make (for film) and maximises the space used for capturing a picture (both film and digital).", "They let the light in through a circular hole, that is correct, but the sensor that's inside the camera has a rectangular shape, and it's smaller than the hole. Only the light that hits the sensor gets recorded into the picture, the rest of the light, out of the sensor, is lost.", "A lens in a camera collects light from a large area and bends it's path into a much smaller area. It does not record the light to form an image. The recording is done by a sensor or film that is in this small area where the light is bent into. This sensor is rectangular and thus the image is rectangular.", "Because the sensor (or film, if you go the vintage route) in which the image is projected is a rectangle. I can go a bit more in detail (as far as I know, I'm just a hobbyst), but the base is just that.", "The round image is croped to a rectangle. How big the rectangle is depends on various factors. First it is dependent on the size of the lense and how much light comes through. Some lenses project on a bigger surface than others. An other important (theoretical) factor is the distance of the lens to the surface the light is projected upon, think about a projector projecting a movie or a slide upon a wall: the larger the distance the larger the surface it projects upon. This cropping is not a bad thing since lenses tend to have errors on the outer edge of the lens. At the edge the image the lens gives starts to deform and give strange colors, just like when you look through a glass of water to the world. So in film you have small format (35x24 mm), medium format (starting at 4x5cm to 6x7cm) and large format (everything bigger) and with every camera type the distance of the lens to the surface it projects on further and further away. In todays digital cameras the size of the image is also dependent on the size of the chip in the camera. First the chip gives the amount of megapixel: a square of 1000px X 1000px is 1 megapixel. The other factor is the actual size of the chip. Chips that are larger give a different image what is mostly seen as a better image."], "text_urls": [[], [], [], [], []], "score": [19, 6, 6, 3, 3]}}, {"q_id": "73rknh", "category": "Repost", "title": "How do vinyl records work and how are they made?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dnskg3x", "dnsjyws"], "text": ["I googled this a few weeks ago, and literally just cannot get my head round it, I've resigned to believing it's actually magic.", "Acoustic analog recording is achieved by a microphone diaphragm that can detect and sense the changes in atmospheric pressure caused by acoustic sound waves and record them as a mechanical representation of the sound waves on a medium such as a phonograph record (in which a stylus cuts grooves on a record) Once cranked through an amplifier, like a record player, what sound waves recorded on the record will be produced."], "text_urls": [[], []], "score": [4, 3]}}, {"q_id": "73rssl", "category": "Repost", "title": "Why do some people put on weight in different areas of their body to other people?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dnsmq9x"], "text": ["RN but this is not my field. I'll wager a somewhat educated guess though. There are two answers. Fat cell distribution, and ascites. Your fat cell location determine where the fat deposits on the body. Women carry more fat under their skin, particularly thighs (storage for milk production). We all have an omentum which is a lacy layer of fat surrounding the abdominal cavity. The bigger we get, the thicker and less lacy the omentum is, in general. Ascites. Alcohol drinkers in particular will stress the liver to the point it becomes leaky. Free fluid will then build up in the belly giving a \"pregnant\" appearance. The omentum could also be thicker which compounds this appearance. As I said. I'm not a doctor or have any specialized experience in this area. This is purely an educated guess based on what I know about the human body."], "text_urls": [[]], "score": [6]}}, {"q_id": "73upba", "category": "Repost", "title": "How do companies like whatsapp earn revenue?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dnt9a4y", "dnt9d0h"], "text": ["It doesn't at the moment really. As more and more people get it and it becomes ingrained even more in most people's routine, that's where they can strike... while they may not go obvious advert routes, they have previously said they will allow people to chat directly with companies they want to hear from.... which sounds basically like an ad.", "Whatsapp is quickly growing. It operates at a loss to sustain the growth, which is funded by investors who feel that it may make money in the future."], "text_urls": [[], []], "score": [4, 3]}}, {"q_id": "73y4ct", "category": "Repost", "title": "why do fans make air feel cold even if it\u2019s just pushing around hot air?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dnu1gzf", "dnu3318"], "text": ["It only works because you sweat. The moving air carries the moisture off your skin, which carries away heat. This is why those spray bottles with fans are so effective and is also why moving air doesn't make you cooler when it's humid (because the already-saturated air can't carry away any additional moisture).", "Air is a poor conductor, but a good insulator. Your skin warms up the air in thin layer surrounding it and the fan blows that air away."], "text_urls": [[], []], "score": [4, 3]}}, {"q_id": "73yvvd", "category": "Repost", "title": "Voltage vs. Current in electricity", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dnu6vls"], "text": ["Current is the amount of electric charge passing a point per unit of time. The unit of current, the Ampere, is equal to one Coulomb (6.24x10^18 electrons) per second. Voltage, or potential difference, is the amount of energy electrical charge gains from being allowed to pass from one point in space (of high electrical potential) to another (of low electrical potential.) The unit of potential difference, the Volt, is equal to one Joule per Coulomb."], "text_urls": [[]], "score": [3]}}, {"q_id": "73zot0", "category": "Repost", "title": "Why is it so hard to pass a gun control law in the US, even though the majority of the citizens are for some gun control?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dnuc5cb", "dnubjly"], "text": ["It's a complex scenario. Firstly, the NRA has an enormous amount of sway with the US government, whether Democratic or Republican. They will try their utmost to prevent gun control being tightened, because they stand to lose a huge amount of money. Secondly, there's a large, very vocal, very politically active segment of the US who are very much in favour of keeping gun laws as they are now, for their own personal gain. This may be driven by fear, desire for power, or other motives. They also tend to be collected into individual states, which tend to vote Republican. As a result, they have strong voting power. And a party that wants to get into power is unable to declare that they want to restrict gun ownership, as a result. Thirdly, the US has gone too far along the path of gun culture. There are now significantly more firearms in the US than people. If the government were to announce a buy-back and subsequent ban, law-abiding citizens would be the only ones who would return their weapons. Criminals would keep theirs. And that, needless to say, is unpalatable to the majority. Put simply, the US desperately needs to tighten gun control, and needs to make it a federal law rather than allowing states to set their own rules. In Nevada, it is shockingly easy to acquire an arsenal of semi-automatic rifles, as has recently been proven. The same is true in several other states. If a federal law were passed, it would be the same for all, and it would be easier to control weapon acquisition as a result. But for that to happen, a party willing to do so needs to be in power of both the House and the Senate - and that is not something that is likely to occur in the near future.", "If you pass such a law, the gun manufacturers stand to lose a lot of money, and they don't like that idea. So, they throw shitloads of money at the government to make sure that such a law doesn't pass."], "text_urls": [[], []], "score": [5, 4]}}, {"q_id": "7414pq", "category": "Repost", "title": "Why can a 30 minute nap do you wonders, but sleeping too long makes you tired?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dnupuo2", "dnup8da"], "text": ["All right! One I can actually answer. So generally it\u2019s actually a 15 to 20 minute nap that does your wonders. A 30 minute nap is almost pushing your luck -of course you may be factoring in the time it takes to fall asleep, too. Sleep happens in roughly 90 minutes cycles and each 90 minute cycle is broken down into four phases. The first phase is the lightest phase of sleep and it lasts about 15 to 20 minutes before you switch into the deeper phases. It\u2019s easy to wake up out of that first phase but each successive phase is harder to wake in the middle of. A power nap seems to improve blood flow in and around the brain, which helps improve peoples\u2019 memory, cognition and many fine motor skills such as playing the piano. There is still a lot of research to be done as to what exactly our brains are doing when we sleep, but it seems like taking a power nap allows you to start reaping those benefits without getting your brain into the depths that will leave you groggy, should you wake up in the middle of them. Apparently a 90 minute power nap will also leave you feeling great and re-charged, but you\u2019re very lucky if you can afford a 90 minute nap before 4 PM each day. [Night School by Richard Wiseman]( URL_0 ) is an excellent read on all things we\u2019ve learned about sleep.", "My understanding of the sleep research is that short naps (no more than 25 minutes) put you in one phase of sleep, but sleeping longer than that puts you in a deeper sleep cycle that takes 1.5 hours. Interrupting that 1.5 hour cycle can leave you feeling groggy and less rested. So ideally you want to sleep for no more than 25 minutes or some multiple of 1.5 hours."], "text_urls": [["https://www.amazon.ca/Night-School-Wake-power-sleep/dp/149735644X"], []], "score": [10, 8]}}, {"q_id": "746sl4", "category": "Repost", "title": "Why do some people always sneeze 2 times in a row and other people 3 times in a row.", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dnw024n"], "text": ["for me at least, i sneeze anywhere from 1-4 times. lately though (past year or so) i have been sneezing like 6+ times sometimes. so yeah i doubt there is anything making someone \"always\" sneeze a set number of times"], "text_urls": [[]], "score": [3]}}, {"q_id": "7479dc", "category": "Repost", "title": "When an organ is removed, like a kidney, what happens to the space where the organs used to be?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dnw0bop", "dnw27rn", "dnw2vfv"], "text": ["The organs is not fixed rigidly in place. It is more like a gym bag where the clothes will be pushed around and squashed between the other clothes and the side of the bag. In the same way organs is squished between other organs, the skeleton and the skin. So any voids will be filled by the other organs.", "Other things fill the space. Our bodies are good at moving everything around to make room - look at a pregnant woman and wonder where all the stuff in the bottom half of her abdomen went to make room for the baby. Hint: it all went up and now she has constant heartburn and can't breathe.", "FYI: For kidney transplants, the bad kidney is more often left inside the person... so they now have three kidneys."], "text_urls": [[], [], []], "score": [34, 31, 15]}}, {"q_id": "747rkj", "category": "Repost", "title": "While traveling to and from a location, it always seems to feel quicker when returning", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dnw3qdd"], "text": ["Because you already \"know\" your way back and does not need to pay attention to not get lost. Also, since you fulfilled your needs, you are less anxious while \"traveling\"."], "text_urls": [[]], "score": [3]}}, {"q_id": "748du7", "category": "Repost", "title": "Why do you occasionally get hickups, after eating really hot food?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dnwbf5y", "dnwjsds"], "text": ["This happens to me when I eat spicy food too quickly. Now I can feel it before it comes on and just slow down for a minute. Seems to help", "Yo ho ho! Yer not alone in askin', and kind strangers have explained: 1. [ELI5 Why do people hiccup when eating spicy food? ]( URL_4 ) 1. [ELI5: Why spicy things often cause hiccups? ]( URL_6 ) 1. [ELI5: Why do I get hiccups every time I eat really spicy foods? ]( URL_5 ) 1. [ELI5: Why is it some people hiccup when eating spicy foods? ]( URL_7 ) 1. [ELI5: Why do hiccups occur, what causes it to stop, and why does it sometimes hurt? ]( URL_0 ) 1. [ELI5 Why do some people get hiccups from spicy food? ]( URL_9 ) 1. [ELI5:Why do some people get hiccups from spicy food? ]( URL_3 ) 1. [Why does eating extremely hot peppers cause hiccups? ]( URL_1 ) 1. [ELI5: why does spicy stuff make you hiccup? ]( URL_2 ) 1. [ELI5: Why do hiccups happen and how can I easily get rid of them? ]( URL_8 )"], "text_urls": [[], ["https://www.reddit.com/r/explainlikeimfive/comments/5ckxdi/eli5_why_do_hiccups_occur_what_causes_it_to_stop/", "https://www.reddit.com/r/NoStupidQuestions/comments/4dwnrq/why_does_eating_extremely_hot_peppers_cause/", "https://www.reddit.com/r/explainlikeimfive/comments/3zis6v/eli5_why_does_spicy_stuff_make_you_hiccup/", "https://www.reddit.com/r/explainlikeimfive/comments/4it9vo/eli5why_do_some_people_get_hiccups_from_spicy_food/", "https://www.reddit.com/r/explainlikeimfive/comments/6utpi1/eli5_why_do_people_hiccup_when_eating_spicy_food/", "https://www.reddit.com/r/explainlikeimfive/comments/1jt52v/eli5_why_do_i_get_hiccups_every_time_i_eat_really/", "https://www.reddit.com/r/explainlikeimfive/comments/6kc5n4/eli5_why_spicy_things_often_cause_hiccups/", "https://www.reddit.com/r/explainlikeimfive/comments/6493v0/eli5_why_is_it_some_people_hiccup_when_eating/", "https://www.reddit.com/r/explainlikeimfive/comments/1n2qsn/eli5_why_do_hiccups_happen_and_how_can_i_easily/", "https://www.reddit.com/r/explainlikeimfive/comments/5ixbbv/eli5_why_do_some_people_get_hiccups_from_spicy/"]], "score": [6, 3]}}, {"q_id": "74a50m", "category": "Repost", "title": "Why do ice cubes pop sometimes when water is poured over them?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dnwo1yh", "dnwqw8d", "dnwo0x2"], "text": ["That's the ice fissuring due to the large difference in temperature causing a high amount of stress and slight expansion on the structure of the ice It's the same concept with a hot glass and cold liquid breaking the glass", "Ice you make in your fridge is under stress. When you freeze ice in an ice tray, the cold hits it from all angles, and the ice forms from the outside in. As you may know, water expands when it freezes. Since the outer shell forms first, the inner water expands, which puts stress on the outer shell of ice- this can also cause the funny shapes you some times see on the tops of ice cubes. When you pour water over ice, that melts away the outer shell, weakening it. The ice cracks because the stress that it is under is not strong enough to break the fully frozen ice cube, but is strong enough to break the weakened outer ice that has been partially melted. What other said about temperature differential is also true.", "Water is warmer than ice, and when ice gets warmed up really fast by pouring water over it there's too much energy brought in for the ice to stay together, and it cracks inside from the pressure and shock."], "text_urls": [[], [], []], "score": [7, 6, 3]}}, {"q_id": "74ajts", "category": "Repost", "title": "How do body wash and shampoo differ?", "title_urls": {"url": []}, "selftext": "Is there really a need to buy separate shampoo and body wash or would either one work well enough to wash both your body and hair?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dnx75oo", "dnxmqdl"], "text": ["The ingredients in shampoo are designed to make your hair soft and shiny whilst maintaining natural oils. Body wash is usually just soap based. Using body wash on your hair will clean it but can leave it feeling dry and less manageable. Using shampoo on your skin can cause irritation and/or a slimy feel due to the extra ingredients not designed for bare skin.", "Soaps and shampoos have things in them called surfactants. This is what makes them lather. They coat the dirt and oil and then wash off. These also have a tendency to dry out your skin. Your hair and skin have a certain pH. Shampoo and body wash also have certain pH. Changing the pH of your hair or skin changes how it feel and acts. For example, your hair is basically a thin strand of protein, coated in tiny translucent scales. When your pH goes higher those scales stand or open up. On a minor scale this makes your hair frizzy, on a major scale its what lets you change the color or curliness of hair permanently. When your oils seep back out and mix with your sweat it creates a protective layer on your skin and hair and rebalances your pH. Anyone who's bleached or dyed their hair and gotten it on their hands can tell you that your skin on your body and the skin on your scalp react very differently to chemicals. Because of all of this, body wash, soap, and shampoo have different conditioners and use different surfactants for different uses. Shampoos are also made to balance out different \"issues\" with your scalp. There are moisturizing shampoos, thickening shampoos, sensitive scalp shampoos, clarifying(which just means it's strips everything from your hair and are often used to remove build up of product). Higher quality shampoos will be more closely balanced to your natural pH. The skin on your body is much rougher than your scalp for the most part and can withstand rougher chemicals and don't generally need to treat any issues unless you have a skin condition. Using a body wash on your hair would be too rough and would strip too much of the natural oils without replacing them. The same goes for face washes. Those will be the most gentle soaps because the skin on your face, neck, and collar are thinner and more sensitive. As for the 3-in-1 soaps, there's nothing technically stating you can't use the same soap for all of those uses but those things really tend to be harsh. They tend to be more targeted to men who are low maintenance because it's all in one and its easy. Ultimately it comes down to what each individual values though. Hope that helped. I'm a licensed cosmetologist btw."], "text_urls": [[], []], "score": [4, 4]}}, {"q_id": "74b48n", "category": "Repost", "title": "How are car blinkers perfectly in-sync for s few seconds, then not?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dnwvynn", "dnww4nj"], "text": ["Because they weren't perfectly in sync. [Here is a gif to show you what you witnessed more eloquently.]( URL_0 )", "> How are car blinkers perfectly in-sync for s few seconds, then not? They are not perfectly in sync for a few seconds, they are at most theoretically in sync for an infinitesimal period of time which they may not even be lit up for. What is happening is that for a period of time they are so close as to be indistinguishable to you and then they are not. Any regular sequences which are not of the same period will gradually tend toward synchronization and then away again afterwards. Turn signals don't have any compelling reason to have exactly the same frequency of blinks so it is the norm that whatever timing method they use is consistent for a given vehicle, but not between different kinds of vehicles."], "text_urls": [["https://media.giphy.com/media/KrzvaTeFSvUk0/giphy-downsized-large.gif"], []], "score": [4, 3]}}, {"q_id": "74ccog", "category": "Repost", "title": "can someone please simplify an EMP?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dnx6api", "dnxakwd"], "text": ["When a magnetic field moves relative to a conductor, or vice-versa, a voltage is generator in that conductor. An EMP is a very big, very fast magnetic field; when it hits conductors (like every wire within range), it generates large voltages in them (because it's so big and moving so fast). These voltages are enough to damage a lot of electronics. Keeping them in a faraday cage, basically a complete layer of metal that is insulated from the contents, can guide this field away from them, thus keeping them safe.", "You know how if you put aluminum foil in a microwave, it will spark and create electric arcs? That's essentially what an EMP does to electronics. Nukes can generate an EMP but usually only when detonated above the atmosphere. This is because the atmosphere absorbs the radiation that generates an EMP before it can do so. Without the atmosphere present, nuclear detonations generate WAY more high energy radiation like Neutrons, X-Rays, and Gamma Rays. All this high energy radiation interacts with the Earth's magnetic field to generate the EMP. It's possible to block the EMP from damaging electronics but it usually requires electrical shielding like Aluminum Foil, Faraday Cages, or burying them underground. This can be bulky and difficult and is hard to integrate into already established electronic devices."], "text_urls": [[], []], "score": [4, 3]}}, {"q_id": "74d4ye", "category": "Repost", "title": "Why do coupons often write \"Cash value 1/100 of 1 cent\" in the bottom print?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dnxdqv6"], "text": ["Coupons were introduced to American customers about a hundred years ago, along with a thing called \"trade stamps.\" You know how you can get 10 hole punches in a card at a coffee shop and then get a free coffee? Same sort of thing. The coupons and trade stamps were a big hit with most customers, but some of them were anxious about this new-fangled invention and felt like they were getting ripped off when they got \"trade stamps\" with their purchases. So various local governments stepped in and said \"Okay, you can keep doing this weird coupon stuff, but you have to give people the option to just take cash instead.\" So all the coupons and trade stamps were assigned some minuscule cash value. Now, a hundred years later, all the people afraid of coupons are dead. But the laws remain. So companies still put on coupons that they are worth some ridiculously small amount of money."], "text_urls": [[]], "score": [9]}}, {"q_id": "74exe7", "category": "Repost", "title": "How did E = mc\u00b2 become a famous equation?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dnxqk5d", "dnxr8t6", "dnxq2hb", "dnxttgn", "dnxq9gb"], "text": ["It stated that energy could be converted into matter and vice versa. That's a big shocker in physics to the layperson. We all know, or think we know, what matter is - stuff we can hold, or at least contain. But energy appears different. Light, heat, motion, they just feel like they're in a different class of stuff. But Einstein says they're the same, and he can prove it.", "What's important to consider is that \"E = mc\u00b2\" is the culmination of decades of painstaking scientific research by many brilliant scientists. In the end it lead to the theories of Special and General Relativity: arguably the most profound development in our understanding of the universe of all time. \"E = mc\u00b2\" is one of the conclusions Einstein was able to draw, after years of hard work and number crunching for conclusive, airtight proof of all of their findings. It is, in fact, an extremely condensed equation and a mathematical explanation of why this equation is true and the mass\u2013energy equivalence is indeed what it is, would require many, many pages to explain. Since us mere mortals couldn't begin to understand all the theories and mathematics behind it all, E = mc\u00b2 became General Relativity's catchphrase as it were. Great marketing, really.", "Aside from being elegant and simple it has a lot of application (nuclear bomb, nuclear fusion, ITER).", "Einstein came up with the Theory of Special Relativity which describes how things behave when they are traveling very fast (i.e. close to the speed of light). One of the main equations in this theory is: E^2 = p^2 c^2 + m^2 c^4 (where E is the energy, p is the momentum, m is the mass, and c is the speed of light). If p=0, then you get E=mc^2 . This is different from the Newtonian equation E = p^2 /2m which works well for large/slow things. The key difference being that an objects mass (multiplied by c^2) can be considered as an energy. Now energy can be converted from one form into another, e.g. from potential energy into kinetic energy. So people could see the possibility of getting energy from this rest energy mc^2 term. This is exactly what happens, for example, when we split a Uranium atom (fission) or combine two Hydrogen atoms (fusion). So the E=mc^2 equation more-or-less leads to Nuclear power. This is why the equation is important in Physics, as to why it became famous in the general public is down to a mix of wanting something short and sweet and the awe people felt for the atomic bomb in the 40s & 50s.", "Einstein was ridiculously famous & Relativity was a huge discovery. E=mc^2 is short and sweet and easy to understand, even if you don't know what it means. Perfect recipe for a pop-culture phenomenon."], "text_urls": [[], [], [], [], []], "score": [11, 7, 6, 6, 4]}}, {"q_id": "74fe17", "category": "Repost", "title": "Why do we see strange patterns when we push on our eyes when they are closed?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dnxsvz4"], "text": ["There are nerves in your eyes which are especially sensitive to light. But that does not mean they will not respond to pressure. They will send signals to the brain which the other nerves will interpret as light."], "text_urls": [[]], "score": [5]}}, {"q_id": "74jv2l", "category": "Repost", "title": "why does 70 degrees from an air conditioner and a heater feel different?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dnyuktm"], "text": ["A thermostat sets a destination, not a course. The output from an Air Conditioner will be in the 50s or 60s. The output of a heater will be in the 90+ range. Once they get to the target temperature they turn off, but they don't output air at the target temperature, it would take forever to reach it that way"], "text_urls": [[]], "score": [6]}}, {"q_id": "74nad0", "category": "Repost", "title": "How are video game environments with vast proportions created? Does it take a painstakingly long time to code or are there any design hacks to create environments?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dnzldtf"], "text": ["Short answer is both. Take for example The Elder Scrolls IV: Oblivion, this was a procedurally generated world(something like how minecraft worlds are created), and probably had some added polish after it. The Elder Scrolls V: Skyrim was a different story, and there were more level designers and less of the world was procedurally generated. So yes, it is painstakingly long but there are also design hacks to shorten the time needed to create an environment, though most of the time the game world is 'better' if its more level designers working, and less hacks to shorten the time"], "text_urls": [[]], "score": [3]}}, {"q_id": "74oizt", "category": "Repost", "title": "Why do stimulants calm ADHD/ADD people down when they have an opposite effect on everyone else?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dnzvyk8", "dnzw2k9", "dnzy4bm"], "text": ["Stimulants can help a person who has poor concentration (like a person with ADHD) to [focus]( URL_0 ). It's related to parts of the brain that make use of a chemical called dopamine which is responsible for the pleasure of anticipating a reward, but people with ADHD find it hard to get that kind of pleasure so they can be hyperactive to try to achieve that feeling. Stimulants make it easier for a person with ADHD to activate the reward anticipation parts of their brain, which suppresses their hyperactive behaviour.", "It doesn't \"calm\" anyone down really. It just makes you focus the energy you have. Some will apear calmer from an outside perspective but its because all of the energy that was being used for 20 things is now being used for 2 things.", "Imagine being bored at school to some place, so your mind wanders, in an effort to not be bored, and you try to find some way to entertain yourself. People with ADD/ADHD struggle with that feeling in many situations other than just school. Now imagine if you could take a pill that made school interesting to you. Now you're paying attention because you aren't worrying about finding something to entertain yourself because you aren't \"bored\" anymore. Now imagine that you don't normally have a problem with paying attention, but you take one of the pills anyway. Now school is more interesting, but this is in addition to the fact that you usually concentrate fine, so now you might tend to act in a hyperactive manner. Also note that if you have ADHD/ADD and you take too big of a dose, you can also become hyperactive in this way."], "text_urls": [["https://allpsych.com/disorders/neurodevelopmental-disorders/attention-deficit-hyperactivity-disorder-adhd/adhd-stimulant-paradox/"], [], []], "score": [16, 8, 5]}}, {"q_id": "74owj3", "category": "Repost", "title": "why honey never expires", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["do004ym", "do05gyw", "do054jf", "do000gh", "do001bg", "do024sh", "do0caq0", "do0uqzc", "do111pl", "do18qv2"], "text": ["It's high in sugar and low in water. Bacteria, like all living things, requires water to survive. Honey has so little water that it will pull water out of any bacteria and kill it. Also, too much sugar is also a good way to kill bacteria. If all the bacteria that get on the honey die, there's none left to produce any of the hazardous byproducts that make food go bad and expire.", "Others have already commented on the low moisture and low water activity being the primary method of preservation. To add to this, bees naturally produce small amounts of hydrogen peroxide when they break down the sugars. Hydrogen peroxide both inhibits growth and can kill certain types of bacteria and fungal spores. Source: Am food scientist", "As others have said, it's the lack of water and resulting osmotic effects that is the primary cause. However, when compared to concentrated sugar solutions, honey has even more antibacterial effects. So there are additional naturally occurring compounds to preserve honey as well.", "Bacteria and mold need moisture to grow - honey has effectively no moisture so it doesn't spoil when properly stored. It can last for centuries even.", "Life requires water. Honey doesn't have enough water content to support the growth of microbes.", "The lack of water preventing bacteria/mold from growing. Also, honey is mostly stable sugars. They don't break down in that environment (assuming a lack of light and heat) so it doesn't go 'rancid' or nasty.", "Why can\u2019t we use honey as an antibiotic then?", "So my honey in my cupboard that is old and crystalizing is not \"bad\" I just can't use it because I can't get it out of the jar?", "Doesn\u2019t oil also not contain water yet that can go bad?", "Perfect spot for a question I've had. My hubby brought home a number of jars of honey that had been sitting for an insane amount of time in his grandparents old house. I want to say somewhere in the vacinity of 12+ years. The stuff looks almost black and it's all solidified at this point, but all the containers have lids on them, so they haven't been open to the air. I think it's all raw honey too. They have beekeepers that use a bit of their land for their hives, and as payment, they give them raw honey, so I'm assuming this is from them. It's still ok? The hubby makes beer and meads and such, and was thinking about using this for his meads."], "text_urls": [[], [], [], [], [], [], [], [], [], []], "score": [1373, 688, 53, 32, 11, 7, 5, 4, 3, 3]}}, {"q_id": "74qwek", "category": "Repost", "title": "What exactly does Cos, Sin, and Tan, measure in a triangle?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["do0fau9", "do0hlep", "do0g3uh"], "text": ["They are the ratios of sides of a right triangle. So you've got a right triangle, and one of the non-right angles is marked. The sine of that angle, for example, is the length of the side opposite (across) from it, divided by the length of the hypotenuse. The ratio of the side next to the angle and the hypotenuse is the cosine, and the ratio of the last combination (the opposite and adjacent sides) is the tangent.", "URL_0 I always drew this for my students when they came in for tutoring. Literally any problem they had from precalc through calc 3 I started drawing a unit circle. Often they would tell me they knew it but we always used it more than once.", "If you know one angle and one side of a right triangle, they tell you the length of the other sides. Let's say you want to know how high your drone can fly. You place it on the ground, pace out 50 feet, then fly it to maximum height. You measure its angle above the horizon to be 75^(o). That's all you need to measure its height: Adjacent side = 50 feet Angle = 75^o tan(75^(o)) = opposite / adjacent tan(75^(o)) ~= 3.7 3.7 = opposite / 50 feet 187 feet = opposite Similarly, we know the drone is 50 feet / cos(75^o) = 193 feet directly away from you,"], "text_urls": [[], ["https://i.pinimg.com/736x/15/51/9a/15519adcc0fecaa912e3927c52e88ec3--calculus-textbook-calculus-help.jpg"], []], "score": [9, 5, 5]}}, {"q_id": "74xjg0", "category": "Repost", "title": "as a non-american, what are HOAs? Every story I've ever heard about HOAs in America makes them out to horrible, petty and just all around pointless. What is the point of a homeowners association? What do they do other than bother people? Are there non-horror stories?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["do1td22", "do1tyu9", "do1t9xo"], "text": ["They're Homeowner's Associations. When you buy a house or condo, if an HOA has been established in the community, you're essentially contractually forced into paying some amount of money each month to fund the HOA, and you agree to follow the HOA's rules. The HOA then typically uses that money to maintain and upgrade common areas like private parks, sports courts, pools, etc. in the neighborhood. The HOA may also enforce rules on what your home looks like form the street. The goal of an HOA is to maintain higher home values through these public spaces and home appearances, which can definitely be a good thing. Too often, though, the HOA leadership becomes petty people on a powertrip, which is where the horror stories usually come from.", "I like our HOA, for the most part. We live in a condo complex so we have common areas such as pool/hot tub, grassy area, landscaping, etc. which need maintenance. The HOA is also responsible for the outside of our condos including roofs, etc. We've had the HOA pay for a contractor when we had termites. They do have rules about what kind of front doors we have and of course we wouldn't repaint the outside (there's no obvious divider on the outside between ours and our neighbor's condos) but our HOA is not that intrusive. Dues have actually gone down while we've lived here.", "In a planned community, a homeowner's association manages shared resources. In a condominium building, for example, the HOA will be responsible for maintaining the outside of the building, the hallways, and the lobby. They also can pass rules about what homeowners in the community are allowed to do with their homes. If you live in a rowhome for example, you probably will not be allowed to paint your part of the outside bright pink with yellow polka dots no matter how much you want. There are certainly plenty of communities that take it too far, but most of them are just the homeowners pooling resources for the upkeep of their homes."], "text_urls": [[], [], []], "score": [11, 3, 3]}}, {"q_id": "753st0", "category": "Repost", "title": "Why is it that in small vehicles (cars, etc), seat belts are present and required - but in large passenger vehicles (buses, limousines), they are not present?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["do37sql"], "text": ["A large vehicle isn't going to stop suddenly from high speed unless it hits something similar size or bigger which is much less likely. It's less likely to be travelling at high speed anyway. It's got more bodywork to crumple and spread out much of the impact over a period of time."], "text_urls": [[]], "score": [3]}}, {"q_id": "755d01", "category": "Repost", "title": "Entropy of space", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["do3nntz"], "text": ["If you have a glass of water at 60F, in a room that is 70F, energy from the room will exchange with the water, and eventually you will have water and room at the same temperature (slightly less than 70F, given a completely closed system). Space is the same. Imagine that all of space consists of one star. Space is 0 degrees K and the star is 6000 degrees K. Eventually the star will burn up all of its fuel, and die. Over billions of years the heat energy of the star will dissipate into space, and the space will be a uniform temperature again."], "text_urls": [[]], "score": [7]}}, {"q_id": "755ect", "category": "Repost", "title": "Why does feces end up being a brown color most of the time? And if it ends up a different color, why is that?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["do3kxjm"], "text": ["Yarr! Yer not alone in askin', and kind strangers have explained: 1. [ELI5:Why is poop almost always brown? ]( URL_4 ) 1. [ELI5: Why poop is brown ]( URL_5 ) 1. [ELI5: Why is it that the stool is always the same brown color (almost) regardless of what we have eaten, and same thing with urine. But if we eat beetroot both feces and urine becomes red? ]( URL_0 ) 1. [ELI5:Why is poop brown? ]( URL_6 ) 1. [ELI5: Why is feces always (generally) the same color regardless of the food you eat? ]( URL_3 ) 1. [ELI5: Why is poop brown and not blue or pink? ]( URL_2 ) 1. [Why is poop brown? ]( URL_7 ) 1. [Why is poop brown? ]( URL_1 ) 1. [ELI5: Why is poop brown? ]( URL_8 )"], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/5u6tas/eli5_why_is_it_that_the_stool_is_always_the_same/", "https://www.reddit.com/r/NoStupidQuestions/comments/68iunt/why_is_poop_brown/", "https://www.reddit.com/r/explainlikeimfive/comments/13j0em/eli5_why_is_poop_brown_and_not_blue_or_pink/", "https://www.reddit.com/r/explainlikeimfive/comments/24t8ry/eli5_why_is_feces_always_generally_the_same_color/", "https://www.reddit.com/r/explainlikeimfive/comments/1lavyf/eli5why_is_poop_almost_always_brown/", "https://www.reddit.com/r/explainlikeimfive/comments/nwtbl/eli5_why_poop_is_brown/", "https://www.reddit.com/r/explainlikeimfive/comments/2db025/eli5why_is_poop_brown/", "https://www.reddit.com/r/explainlikeimfive/comments/jm34m/why_is_poop_brown/", "https://www.reddit.com/r/explainlikeimfive/comments/18dlvl/eli5_why_is_poop_brown/"]], "score": [5]}}, {"q_id": "75bkb2", "category": "Repost", "title": "why do voices sound high pitched when sped up?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["do4wr8a", "do4vbtb", "do4x8lk", "do4vcpj", "do5uavk", "do59tpy", "do4xgpl", "do4wq20", "do5f0o9", "do5fk3q", "do4y7ip"], "text": ["This has been answered accurately already so I'm gonna try to do a better job of explaining it to a 5 year old. When you talk, there are \"strings\" (not actual strings, more like folds) in your neck called vocal cords that make the talking sound. The faster they move (or vibrate), the higher the sound they make. Children's voices sound higher than adult voices because children's vocal cords aren't as big, so they're able to vibrate faster and make a higher pitched sound. The same thing happens if you take that sound and play it even faster. You're artificially making the vibrations of the sound move faster so it sounds higher pitched. This is true of any sound, not just voices. ***Edit***: In case I simplified too much... here's a longer answer for anyone who wants to go a bit deeper, or who wants to complain about slight technical misunderstandings of what my simplified explanation meant: When vocal cords are smaller they naturally vibrate faster when air is pushed by them, which means the frequency of the audiowave pattern they produced gets repeated quicker. That's the frequency, which determines how high we hear its sound. The faster something vibrates, the higher pitched it is. You do the same thing when you take a recording and run it faster. You increase the frequency of the audiowave pattern, so the pitch gets shifted up. So the \"Explain it like I'm 18 and just haven't taken physics for some reason\" answer is that in audio, pitch = frequency, and frequency = wavespeed / wavelength. If you speed up the wavespeed without changing the wavelength, you get a higher frequency, which equals higher pitch. But that answer had already been given when I wrote this, so I went for something a little more illustrative, and a lot of people seemed to find it more helpful. ***Final edit*** For accuracy I adjusted some words and added some notes in parentheses. I originally talked about the length of the vocal cords instead of just overall size, which, while accurate, is not AS accurate, and just seemed to confuse the issue.", "Pitch is determined by the frequency of the sound waves. When you speed up a playback, it shortens the duration between the sound waves, resulting in a higher frequency and thus a higher pitched sound.", "> Pitch, noun: the degree of inclination or slope; angle. As in \"pitched roof\". When you have waves like this: _ _ _/ \\_ _/ \\_ _/ \\_/ \\_ with time along the bottom axis, and you squeeze the time, you get this: /\\ /\\ / \\ / \\ / \\/ \\ So you've **literally**, by the above definition, increased the pitch.", "The pitch of a sound is based on its frequency. When you're speeding up a sound, you're doing the same amount of \"sound waves\" in fewer seconds. e.g, you've increased the frequency.", "Everyone has explained frequency and /u/AssaultedCracker even brought up vocal cords, but nobody has explained why bringing up the frequency makes things sound *unnaturally* high pitched (not just as if a singer were singing higher), so let me cover that. When we talk or sing, the sound we produce is made by two things: first, the vocal cords make a pitch, or a basic tone. Then the rest of the inside of the mouth and throat *filter* that sound, emphasizing some parts (frequencies) and getting rid of others. This is how we can tell vowels like \"e\" and \"o\" apart: the basic pitch may be the same, but by moving our mouth and tongue we change the resulting sound that comes out. If you've ever brought a glass or cup to your ear and listened as you move it closer and closer and eventually seal it off, you've experienced filtering. The cup changes which frequencies are emphasized or removed and things sound strange. In general, males have larger \"filters\" (mouth and throat) than females and kids have smaller ones. The larger the filter, the lower the general frequencies. This is why male voices sound deeper and kids' voices sound higher pitched. The range of the vocal cords also changes, but a guy and a girl may be singing the same note and yet the guy will still sound deeper on average. The interesting thing is that when we sing higher or lower the basic pitch changes (the note our vocal cords make), but the rest stays the same: the filter still filters the same frequencies. But when we speed up a recording, we're not only changing the base pitch but also everything else, including the effects of the filter. And so, slowing down a recording of a woman makes her sound more like a man, and speeding it up makes her sound more like a kid. And if you go high enough, it'll start sounding like a Smurf, which is what we've come to associate with unnaturally sped up human voices. This component of speech besides the base pitch is called the *formants*. Speeding up audio shifts the formants up higher in frequency. And that's why speeding up a voice makes it sound funny and high pitched. Specialized software (like Melodyne) can be used to edit this, changing the pitch of a voice without altering the formants or the tempo, or any other combination of those. For example, GlaDOS from the Portal games is a female voice that was edited to \"autotune\" the pitch but also with the formants shifted higher to make her sound oddly childish and robotic. Similarly, the stereotypical \"bad guy voice\" in games is often just a voice with the formants brought way lower with digital editing.", "I have a question on that, can you keep the same pitch but speed it up?", "1. frequency means how often something happens 2. sound is made up of frequencies 3. speeding up sound means increasing frequency 4. increasing frequency is raising pitch now if your question is why pitch increases with frequency its similar to asking why some frequency of light is a certain color: it just is, based on the medium the waves are in", "Though it is correct that faster playback pushes pitch upwards, an additional important aspect is that the formant areas of the voice (the resonant areas of the voice which distinguishes the tone from a male and female singing the same notes apart) is also pushed higher, making it sound chipmunk-y when sped up or beast-y when slowed down.", "Corollary question: Is this related at all to the doppler effect?", "Sound is made by shaking. If shaking is slower, sound is lower. If shaking is faster, sound is higher. If you take a slow shake, and speed it up, the shaking is faster, so, the sound is higher.", "Let's do this: try to tap water with your finger in the same spot keeping some tempo. You will see that you create circular paths around your finger. That circular path, is a wave, which has highs (the highest point of the wave) and valleys (the lowest point of the wave) Now, sound is a wave. Try to tap in the water by moving your finger in some fixed direction (=on a straight line): you will see that the valleys of your waves are approaching in the direction you are moving. If you don't have water around to try the experiment, here you are a [video]( URL_0 ) Okay so, we said sound is a wave. A wave has a frequency which is \"how many valleys that wave generates in a second\". So, when you tap without moving your finger, the wave you are generating has a fixed frequency BUT the waves you generate moving your finger, has an increased frequency on the direction you are moving and a decreased frequency in the opposite direction because, valleys are going further from each other. Higher frequency = higher sounds Lower frequencies = lower sounds There you go :)"], "text_urls": [[], [], [], [], [], [], [], [], [], [], ["https://youtu.be/JmpChd5D0d0"]], "score": [3692, 1313, 153, 54, 34, 19, 12, 8, 5, 4, 4]}}, {"q_id": "75k0mr", "category": "Repost", "title": "How does clicking a box to confirm you're not a robot stop robots?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["do6r3uy", "do6r5fu", "do6r0iq"], "text": ["The captcha isn't checking that you clicked the box. But how you clicked the box. What was the path of the mouse cursor movement. What was the delay in movement. What was the speed of the movement. What were the initial and ending coordinates Applying heuristics, it can give a confidence level if it matches any known bot clickers. And your data is compared to all other human and bot clickers to see if you are a bot clicker", "What's actually being measured is the way your cursor moves towards the box, how quickly it moves, and how quickly/accurately it clicks the box. Humans tend to move the cursor imperfectly, and this is what the pop-up expects. You can make bots that move the cursor more organically, yes, but this tends to filter out the majority of low-effort bots.", "It takes note of your browser user-agent, time you spent on that page, your mouse movement inside the box etc. If it's still suspicious, you have to do an image recognition task, which is not simple for a computer to do."], "text_urls": [[], [], []], "score": [28, 12, 5]}}, {"q_id": "75klnq", "category": "Repost", "title": "How does pain medication such as advil or tylenol \u201cknow\u201d where the pain in your body is and how do they then go about counteracting it.", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["do6vw0t"], "text": ["Pain medicine works systemically. It does not \"know\" where pain in your body is. Various pain medications work in different ways. We're still not sure exactly what Tylenol (acetaminophen/paracetamol) does. Advil (ibuprofen) isn't a great painkiller, but it is really good at reducing inflammation, which can cause pain in itself. It does have some relatively minor pain-relieving effects as well. It attacks [the enzymes that cause inflammation.]( URL_0 )"], "text_urls": [["https://en.wikipedia.org/wiki/Cyclooxygenase"]], "score": [6]}}, {"q_id": "75n9us", "category": "Repost", "title": "How do birds (especially pigeons) determine what is edible and what not?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["do7k7x7"], "text": ["Experience, just like humans. As children, we frequently attempt to eat pretty much anything that's put in our general vicinity. Some things taste bad, some things are hard, some things are tasty. We quickly learn which things are tasty, and focus on those things as a food source as we grow up. We also get additional information from our parents and peers, who eat things around us and may feed us as well, adding to our experience of edible foodstuffs. Pigeons, other birds, and other animals learn through the same process."], "text_urls": [[]], "score": [3]}}, {"q_id": "75ntx8", "category": "Repost", "title": "Why aren't the computer keyboard letters placed in alphabetical order?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["do7kr3i"], "text": ["They tried to do this for typewriters originally but people were too fast and jammed the mechanisms. They switched to qwerty and it and stuck since."], "text_urls": [[]], "score": [3]}}, {"q_id": "75rm6p", "category": "Repost", "title": "How did cartographers create accurate maps prior to the days of air travel?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["do8dke1", "do8ippt"], "text": ["First: they simply weren't as accurate. Second: surveying. Pick a point, measure the distance and direction to some other point. Repeat until you have lots of points, and make a map with that info.", "There is an entire branch of engineering known as Surveying. These are the guys you see out on the side of the road with tripod looking things. George Washington trained as a surveyor when he was young. Basically you start from a known point, setup your equipment, and have another guy hike to Point B with a long stick. He stands there with the stick and you look through your equipment and note the angle, height, and distance between A & B. Then you move on to point B, he goes to point C, and your repeat. Do this enough times and you have the data you need to draw a map, using a little Trig to help you. The equipment has a gotten fancier (lasers are used for accuracy) but the basic concepts are the same."], "text_urls": [[], []], "score": [11, 7]}}, {"q_id": "75svu9", "category": "Repost", "title": "How does alcohol make you drunk?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["do8pfw7", "do8qewv"], "text": ["When you drink alcoholic beverages, the ethanol (responsible for making you drunk) gets absorbed from the stomach to the bloodstream. The liver will break down ethanol up to just carbon dioxide and water in a long complex process, meanwhile some of the ethanol will pass through our cells in our brain if the liver has its queue full of ethanol waiting to be broken down. Ethanol has an interesting perk that can depress the neurons responsible for tasks such as motor function, speech, etc. This makes the intoxicated feel \"liberated\" or \"sluggish\". however once more of ethanol enters your brain it gets worse; nausea, vomiting and unconsciousness are the common symptoms of alcohol intoxication. That's the simplest of how alcohol can get us intoxicated. TLDR: when you drink too much, unprocessed ethanol can get to your brain and interfere with the cells there, making you groggy and have slurred speech as some of the common side effects.", "The main thing in alcohol that has an effect is [ethanol, or ethyl alcohol]( URL_0 ), a surprisingly simple molecule, especially compared to most other drugs. Beer is about 3-10% ethanol, wine is 10-15% ethanol, and liquours are about 40% ethanol. Ethanol gets absorbed into your bloodstream, and from there can pass easily into your brain. Once in the brain, it has a **ton** of effects. The biggest one is probably activating a type of protein on nerve cells called a GABA receptor, which essentially \"turns the neuron down\" (makes it less likely to activate). Another major one is that it blocks another protein called an NMDA receptor, which tends to activate neurons--so by blocking it, it again turns the neuron down. Like everything having to do with the brain, exactly how we go from that to the effects we notice is insanely complex and not completely understood. For various reasons, it tends to \"turn down\" neurons in certain brain regions more than others. It hits the cerebellum (at the top of the back of your neck), which is important in controlling your movement. It hits your prefrontal cortex (right above your eyes) pretty hard--and that's an area that's involved in \"higher\" functions like planning and decision-making. Most seriously, it also affects your brain stem, which is the part of our brain that controls little things like our heart continuing to beat, our lungs continuing to breathe, maintaining consciousness, etc. The ELI5 version: imagine your brain is a giant company headquarters office building filled with thousands of workers in different departments. Alcohol is like a computer virus that gets into the network and starts making the computers in a bunch of different departments run incredibly slowly and crash."], "text_urls": [[], ["https://lifeischemistry.files.wordpress.com/2011/11/800px-ethanol-3d-balls.png"]], "score": [7, 3]}}, {"q_id": "75tdbl", "category": "Repost", "title": "What is the differences between Hepatitis A, B, and C?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["do8tncp", "do8syxj", "do97d9u", "do99k29"], "text": ["The hepatitis viruses (including D and E also) were identified in a time when biologists and medical professionals knew very little about viruses, or where able to classify them appropriately. The word hepatitis means \"inflammation of the liver,\" so naturally this is what all the hepatitis viruses have in common. They all cause some form of inflammation in the liver which leads to symptoms that are similar. Hepatitis A is in the picornavirus family of viruses, same family as polio. It's an illness that people get by drinking or eating contaminated foods (this is refered to as fecal-oral transmission) often in third world countries where sanitation is poor. It looks and feels way worse than it is, lasting only one month and almost never killing anyone who gets it. Hep B is a member of the hepadnovirus family. It's transmitted through sex and needle sharing, making it a blood borne pathogen. It looks much like hep A at the onset of illness, resolves, but unlike hep A which has no carrier state, hep B has a carrier state which often times develops into chronic hepatitis (chronic liver inflammation) over the course of many years, and often presents with kidney failure and even liver cancer. whether or not this occurs depends on the persons immune system. Unlike hep A, when we find hep B infections we treat them aggressively with antiviral medications. Hep C belongs to the flavivirus family, same as West Nile virus. It is transmitted only through blood, which makes it most common in people who share needles. Unlike hep B, hep c infections become chronic most of the time, leading to liver cirrhosis (hardening) and also liver cancer, same as hep B, but much more commonly. Infact, hep c is the most common cause of hepatocellular carninoma. We treat hep c as we do hep b, but cannot vaccinate against it (as with hep b) because the virus itself is too variable in the way it coats its outer shell. In summary, the hepatitis viruses are not a family of viruses. They are a group of viruses from different famililies that all happen to affect the liver in some way.", "They are caused by different viruses and therefore cause different illnesses. While they all cause \"hepatitis\" or inflammation of the liver, they are far from the only viruses that cause that. EBV (the most common form of \"mono\") also can. As can CMV and other viruses...as well as many non-viral causes (autoimmune diseases, Fe overload, tylenol toxicity, fatty liver, alcohol, etc). Speaking in broad strokes, Hepatits A tends to be transmitted through a fecal-oral route...meaning fecal contamination of food or water and is typically ingested. It often causes a brief illness that most people get over from, but can be dangerous to certain groups of people. Hepatits B is a virus made from DNA (the other 2 are RNA). It is usually sexually transmitted. It can also occur through blood-borne transmission (transfusions, sharing needles for IV drug use) and in some cases can even be passed from mother to child during pregnancy and birth. Unlike Hepatitis A which usually is only a transient illness, Hepatitis B can lead to immunity in some people, but other people can develop chronic disease which can eventually lead to cirrhosis or liver cancer (\"hepatocellular carcinoma)\" Hep C is usually transmitted by the blood borne route. Most people do not develop immunity to it and have chronic infection which ultimately leads to either liver cancer or cirrhosis. There is no vaccine for Hep C but there are new drugs that can kill the virus. Meanwhile, there are vaccines for HepA and HepB.", "From my experience Hep A, wasn't nearly as bad as you'd expect. I somehow managed to get Mono (EBV) and Hep A (as well as tonsilitis and pharyngitis) at the same time, ended up in hospital for a week. My only real symptoms of EBV and Hep A were hot feverish sweats and headaches from EBV like a severe cold/flu without coughing and sneezing etc and yellow itchy skin coupled with really strong smelling brown urine and white excrement. Sleep was not my friend for about a month, thats to say uninterrupted sleep - even now 3 months later I can't get enough rest - what I wouldn't give for a good 12 hours sleep a day. The only reason they kept me in hospital was to make absolutely certain my liver recovered ok and that there wasnt some kind of underlying illness on top. For anybody interested both the hospital and my personal Dr seem to think it was caused by my work, I'm a broadband, and phone technician. I go into people's homes to fix faults, I used to have drinks sometimes when offered - not these days. Also I have to work in manholes in the street but take precautions but could also be that somehow. This was probably about 3 months ago and I am still struggling with energy levels at work and home - about 1 or 2 in the afternoon I'm ready for a nap.", "Just to add, while Hepatitis B is transmitted by blood contact, it is extremely transmissible via this route. An outbreak in Sweden among cross-country runners was tracked to a Hepatitis B carrier who was among the faster runners - small cuts on his legs from grasses/flax and twigs provided a means of infection for following runners. In New Zealand, there is a high endemic rate of infection among Polynesian groups due to maternal infection of babies who generally develop chronic Hepatitis B infection (95%). This impacts the general population, with \"playground infection\" a common infection vector. I've been involved with treatment trials for chronic Hepatitis B, and there have been some really positive developments."], "text_urls": [[], [], [], []], "score": [556, 41, 6, 3]}}, {"q_id": "75ztw4", "category": "Repost", "title": "How do we know how much humans contribute to climate change when the Earth has always had vastly fluctuating temperatures?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["doa6uuu", "doa6ngw", "doa6ib1"], "text": ["I don't think we could ever say with 100% confidence how much of climate change is because of human action, but we can draw reasonable conclusions. As an example, we can see and measure very clearly that carbon emissions and other greenhouse gasses trap heat in the atmosphere. We can also see and measure how we are producing those emissions. We can also see and measure that there is a strong correlation between our emissions and the rising temperature. We can also use other measurements to see what the atmosphere has looked historically and compare that to where we are now. From those measurements and observations (in addition to other measurements and observations) conclusions are drawn. If we know that there is a strong relationship between carbon dioxide in the atmosphere and global temperatures, *and* we know that we are producing record amounts of carbon dioxide, we can reasonably conclude that our emissions are contributing to rising global temperatures. There is obviously some debate about how precisely we can measure our emissions and its relationship to the climate, but we can tell very clearly that we are responsible to a high degree (no pun intended). One of the best visual examples of how we know how much we're contributing is in this comic: URL_0", "Well, we can look at rates of change compared to historical fluctuation. Turns out, temperatures are rising higher and faster than we see in any of the \"natural cycles\" of which we have records (and we *do* have records, thanks to things like ice-cores. Science is *cool*). Combine this with the close correlation between increased greenhouse-gas emissions and climate change, also visible from historical records, and with the fact that we know the effects greenhouse gases can have on small scales, and you get some pretty strong evidence.", "We can look at patterns of what we think the temperatures were like in the past (using things like ice cores in Antarctica which traps \"atmosphere\" from the past). We see gradual changes over the thousands of years, and then very sharp changes in the last 150-160 years. Changes that would have taken thousands of years in nature. We haven't been manually recording temperatures for very long. Since about the industrial revolution, which is where we usually get concerned with human activity on the environment (as things changed dramatically regarding what we put into the atmosphere and water)"], "text_urls": [["https://xkcd.com/1732/"], [], []], "score": [7, 3, 3]}}, {"q_id": "762lp7", "category": "Repost", "title": "whats the difference between soap and body wash?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["doawljd", "doax1se"], "text": ["Bar soap is a detergent (cleaning) chemical that remains in solid form at room temperature, and doesn't immediately dissolve when put in running water. Body wash is also a detergent, but its chemical form is more like shampoo in that it's pre-dissolved in a small amount of water. Because it's already dissolved, it's more convenient in a number of ways, but less convenient in some others. The conveniences are that it can be spread and turned into bubbly foam much more easily than soap can, and manufacturers can load it up with additives like strong scents and ingredients like skin conditioners that a bar of soap just can't hold. And because its packaging is permanent, you don't have to deal with grody, slimy hair-covered bars of soap that have gone a little soft and are shared with other people. But the compromise is it's more expensive as a liquid to package and ship, and you go through it a lot more quickly due to the water content so you end up buying a whole lot more.", "Also, body wash creates a lot less soap scum in the bathroom. Went to boot camp before body wash wash became popular (1998). My RDC (drill Sgt for those not familiar with the term) forced us to only buy prell shampoo for use as both hair and body cleanser. He did not want to see a bar of soap anywhere. Reason being that the prell did not create soap scum and we passed inspection more often. another fun fact....barbasol shaving cream is great for cleaning showers and the bottoms of shower shoes.!"], "text_urls": [[], []], "score": [10, 6]}}, {"q_id": "767x8w", "category": "Repost", "title": "SSRI's reinforce depression", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["doc40ss"], "text": ["There's a couple problems with this. Firstly, the model that depression=low levels of serotonin in your brain is oversimplified and certainly not wholly accurate. For one thing, we don't have a way to measure the levels of serotonin in living subjects. In addition, some people with depression likely have normal and even above-average levels of serotonin in their brains. Secondly, drugs like SSRIs increase the concentration of serotonin in the brain right away--but their effects on mood don't manifest themselves for weeks later, after a whole series of cascading reactions happen in the brain, which probably include reducing the number of receptors for serotonin making the increased serotonin less effective than it was initially. Secondly, you would have to find some drug that binds to a target which causes the brain to increase its amount of serotonin production in order to test this. When pharmacy identifies a drug which is effective for some condition, most research in that area goes into refining variations of the drug that have better efficacy, safety and reduced side effects, rather than looking for entirely new drugs (cost much more with much less likelihood of attaining benefit). There are certainly some ground breaking new drugs out there, but that isn't where most new drugs come from."], "text_urls": [[]], "score": [3]}}, {"q_id": "76byq7", "category": "Repost", "title": "How are games cracked?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["doct1nv", "doct3l2"], "text": ["The executable files of a game are basically just a bunch of machine code. Machine code are instructions executed by your computer. By using a so called Dissassembler, you can turn the machine code into a somewhat human readable format called \"Assembler language\". If you are good, you can then analyse the code and modify to circumvent copy protection mechanisms, e.g. by taking the copy protection code out or jumping over it.", "Crackers basically change the inside programing of it For example : If a game has an online protection (that requires to be online to be played), they'll modify the code, to make the game think that you are actually online. /u/dale_glass also answered this 2 years ago :) > Some games come with code that makes it hard to run a copy by just possessing the data for it. For instance, it may make you enter a serial number. You copy the CD fine, install it, and it asks you for the number. You don't know it, so the game refuses to work. > Well, somewhere inside the game there is logic like this: > Ask user for serial number > Perform some operation to check the number. For instance, all digits should sum up to 9. > If the answer is right, continue > Cracking is just interfering with this logic. You can modify the code to jump past the verification step. You can make it still ask for the serial number, but accept any number at all. You could flip the logic around so that it accepts only invalid numbers. Etc. > This was the early era of cracking. Then the companies started making things more complicated. The program may be encrypted and self-verifying, so not only you need to break the encryption and make the change, but also find how it checks itself and defeat that as well. > Some are more devious and don't make it obvious that they know something is wrong. Instead the game runs, but breaks something subtly in such a way that the 5th level becomes impossible to finish. > Any kind of protection is breakable, but with enough effort it's possible to make something that requires considerable thought and time to get around, and it's quite possible that if the protection is good enough the game will remain uncracked for months. Hope it helped ;)"], "text_urls": [[], []], "score": [6, 3]}}, {"q_id": "76bznf", "category": "Repost", "title": "How were the Buddhist monks who self immolated able to show no pain at all?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["docvypt", "doczdpc", "dod6avd"], "text": ["Many of these monks are able to achieve a meditative state, which allows them to focus to a seemingly superhuman degree. Often, when consumed in flames that are hot enough, the nerves near the surface of the flesh are burned quickly, so the pain would be very intense, but relatively brief. Following nerve-death, shock sets in, which causes a flood of chemicals to the brain, some of which block the sensations of pain coming from still-living nerves, and some of which trigger a fight-or-flight response. The combination of uncommon focus and the physical effects of shock, adrenaline, etc make the monks appear calm and apparently in no pain. There have been many self-immolations recently in south east Asia, and if you look at the (shocking and upsetting) photographs, you see that most of them light themselves and immediately begin to run around, flailing and panicking. Most of these recent immolators are not monks, and not practiced in meditation and mental focus. They run because their fight or flight response to the pain of burning causes them to try to flee the danger. Running while in flames can provide some relief, clearing the face and airways of smoke and heat, so the victim may remain conscious longer, having inhaled less of the hot gasses and smoke, and more of their nerves remain intact and responsive for longer, causing greater levels of shock and higher, more prolonged pain. The famous monks are absolutely in terrible pain, but their mental training allows them to better tolerate the response to pain. Coupled with the fact that they remain motionless, the fire consumes their flesh and nerves quickly, they are overcome by inhaling hot gasses and flame, and their systems begin to shut down and succumb to the trauma more quickly and \"consistently\" than people untrained in meditation. Simply, they show no pain because they have trained to tolerate pain. Control over the body's response to stimulus (physical and emotional/mental) is a central purpose and goal of most Buddhist meditative traditions.", "The real answer is opium, although the Buddhists would claim that those monks could withstand pain just by entering a deep meditative state.", "Basically, we are extrapolating from a single case of Th\u00edch Qu\u1ea3ng \u0110\u1ee9c in 1963, which is the only case I am aware of that was captured on film. We have no idea if others ran around screaming. In his case, it was likely combination of mediation and strong will, possibly with drugs thrown into the mix. Also, while obviously it is going to be extremely painful, the pain might not last very long. If you covered your entire body with an accelerate, the initial shock of all those nerves firing at once could last long enough for asphyxiation and nerve killing third-degree burns to set in. It might be harder to suppress the horror of your mutilation and impending death than the pain itself."], "text_urls": [[], [], []], "score": [142, 9, 6]}}, {"q_id": "76dg9o", "category": "Repost", "title": "Why does cold water taste better than warm or room temperature water?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dod3kvn"], "text": ["Basically, because the cold further stimulates the receptors on your tongue that can tell if your drinking, and make you feel hydrated."], "text_urls": [[]], "score": [5]}}, {"q_id": "76girz", "category": "Repost", "title": "How does radiation cause cells to mutate? What is actually happening to them?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dodu5jz", "dodx4t3"], "text": ["Radiation physically damages your DNA, which can cause cells to replicate improperly. Imagine having a blueprint for a house you want to build, but you accidentally light part of it on fire. You now have to build the house with part of the blueprint missing, and even if you use your best guess as to what was in the blueprint before, there's a very good chance you'll end up building the house wrong.", "Ionizing radiation can cause energy to be absorbed by electrons. Because electrons are involved in chemical bonds, this can cause chemical bonds to break and/or new chemical bonds to form. If this happens to DNA, it damages DNA. Cells have various ways of repairing DNA, but this doesn't always perfectly fix the problem. So, you can end up with a cell with changed DNA. Changes in DNA can have various consequences, like cells producing proteins which are changed from their normal arrangement, and function differently."], "text_urls": [[], []], "score": [19, 5]}}, {"q_id": "76gjtu", "category": "Repost", "title": "Why does alcohol work as a sterilizing agent?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dodu8ul"], "text": ["Alcohol breaks down a cell's wall, and the cell falls apart. Imagine a liquid that when poured over a balloon just destroyed the rubber part of the balloon. Then all the water and such pours out and the cell is thus killed, and this works on nearly all cells (not 100%, but roughly 99%)."], "text_urls": [[]], "score": [23]}}, {"q_id": "76hzi2", "category": "Repost", "title": "Why, in humans, are males generally larger than females when it is the opposite in most other species?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["doe5w4o", "doe5u7g", "doe55ek"], "text": ["Humans, like most non-human primates, have sexual dimorphism in which the males tend to be larger than the females. Some primates (like chimpanzees and bonobos) see the males almost twice the size of females. Sexual dimorphism appears in body size, muscle mass, canine teeth, craniofacial structure, and even sometimes deepening voices. There are very few primate species that have reverse dimorphism (females larger than males), so it appears to be \"normal\" that humans display the same dimorphism that other primates \"typically\" have.", "Females are larger when mating is just about finding the female and doing it. Males are bigger when you have to fight other males to mate. Being big is expensive, its easier to be a spider that has to catch a couple of flies to reach sexual maturity than it is to be one that has to eat hundreds. Males just need to mate. Make some spunk and fire it up the ol' baby hole. So they just get to the point they can spunk and then they want to use all energy finding some strange. Females have to make babies, which is super hard, and the bigger you are the more bigger stronger babies you can have, so females want to be big. However, if you're a male that has to round up a harem of ladies, you have to be big enough to fight off the next bozo who wants your ladies. Or you have to be big enough to steal the ladies from the other bozo, so being bigger makes you better at kicking Chad's arse and stealing his Stacey. Human/prehumans evolved under a system of tribal harems, with common raiding for mate stealing and rape. So you have to be able to be bigger to defend your cave Stacey's from Chad-Ugg's, otherwise you're getting cucked. Our own system is rather unique but similar mate protection systems exist with larger males, gorilla, lions are famous ones. And there's loads of male competition examples too.", "Fighting. In species where males fight each other to gain access to females, the males will be larger. Do humans be fighting each other at the club to try to \"win a girl\"? You bet they do. There is a wide range of sexual dimorphism in the animal kingdom, with many examples of both males and females being larger. Females can't be too small because they usually still have to give birth to the young. One of the most extreme is with angler fish where the female is much larger. The males are not much more than swimming reproductive organs."], "text_urls": [[], [], []], "score": [36, 25, 14]}}, {"q_id": "76i19b", "category": "Repost", "title": "If electricity speed is about 300,000 km/s, why does ping of internet depend so much on the distance?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["doe8ddd", "doey0bt", "doeajnv", "doe5rsp", "doen5nt", "doeadw3", "doed7k7", "doe6bf6", "doe5vdn", "doeqouj", "doepmen", "does1x9", "dof3skz"], "text": ["Imagine that all cars, freight ships, trucks, and airplanes would move at light speed. Now think about how long it would take to send a package around the world. Of course it would be faster now, but it wouldn't come close to the speed of light. _Moving the package_ would take almost no time, but the package would still spend a significant amount of time being inspected, loaded, unloaded, etc... This is essentially how the internet works, too. Many of the same words are used here as well: traffic, package, destination, route, ... The information _moves_ at light speed, but spends a lot of time being _routed_ or even queued. Just like you don't have a dedicated road to every person on earth, data packages have to manoeuvre through a network of shared connections. Imagine you're a router in such a network and you receive a package labeled with the destination \"216.58.207.78\" and you're connected to five other routers. You're gonna have think about where to send this for a bit unless you would want to send it to all of your router friends, which would make the internet wildly inefficient. On top of that, as several people already pointed out: When looking at the scale of the earth the speed of light suddenly becomes significant. Going from Los Angeles to Berlin at light speed will take 31ms. Go back and forth (that's what a ping does) and you're at 62ms. That's already enough to ruin most online games. The overhead from routing roughly doubles the travel time, so in practice you would be working with a ping of around 124ms, which will make the game feel like you're wearing oven mitts. EDIT: As /u/HakushiBestShaman pointed out, the information doesn't actually travel through the cabel at light speed, but quite a bit slower [at around two-thirds light speed]( URL_0 ). Taking that into account it seems that the overhead from routing is quite low for long distances along _common_ routes, e.g. US < - > EU.", "The speed of light is 300,000 km/s (in a vacuum), the speed of an electrical signal in copper cabling is probably closer to 120,000 km/s, and there are things like drift and collisions that present problems. When you are sending a signal across the internet, that signal isn't just travelling in copper. If you're on WiFi, it's first travelling through the air as a radio signal. Then it's hitting an access point which will likely convert the signal to copper. Then it will probably go to the cable modem, which will transform the signal again so that it can travel across coaxial cable to the neighborhood junction. From there it shifts again in shape and enters the cable provider's network. That's still copper until it gets to a point where it's reasonable to have laid fiber and reasonable to splice into it. The signal is converted again, but this time it's blended with other traffic. Who knows how many hops from there until it reaches a network bridging point between providers, then across the adjacent providers network until the desired endpoint is reached. All this combining and converting signals is problematic. All sorts of things can happen along the way to mess up the message. Anything from regular old drift to radio interference to electromagnetic interference to stinking cosmic rays or just bad luck. So there's a language that all of these components speak at layer 1/2 to help ensure that the communication is clear and reliable. (layer 1 is the physical layer, e.g. the actual components, layer 2 is the data link layer, basic electrical communication is defined at both levels). Then there are the things that happens at level 3 - the network layer. This is the routing and switching. These are the \"hops\" you see on a traceroute. Kind of. Basically, these are the components that send all the right signals in all the right directions, put everything into packets, do all the sequencing. We think about TCP/IP as sort of the base level of communication, but that doesn't even start until layer 4. At layers 1, 2, and 3 there's all kinds of groundwork that needs to happen before TCP/IP can even be a thought. All of these different components need to have connectivity. They need to know about each other. They need to have a common language. All of that means signalling. And that means signalling on the same set of connections that your data is travelling through. We think of a web request as data going to the server, data coming back from the server. No... At layers 1, 2, and 3 there is a lot of off-band bidirectional communication so that everything along the way knows what is what. You don't want to send signal down a dead path. You want to prefer shortest pathways. You need to be aware of other potential pathways. You need to know what language the other components of the network speak. You need to tell them about you. All of those bi-directional conversations... well every bidirectional stanza effectively doubles the length of the path a signal has to take. Now when you get to Layer 4, there's TCP/IP. The reason so much of the internet uses TCP/IP is that it's a reliable protocol. Lot's of extra communication happens to get something going. Starting a connection means Syn - SynAck - Ack. That just tripled the distance required. Within TCP, messages are cut into chunks of transmission sized data. Intelligent endpoints will inspect those chunks and do things with them along the way. It could be resequencing (not every packet comes in order). It could be rejecting. It could be forwarding. It could be re-packaging and sending along. It could be re-packaging, splitting, and sending on. The decision for what to do takes processing power and time. Every \"hop\" you see in a traceroute has these decisions to make and adds time to the transmission. It can also mean requests for re-transmission, again doubling the signal distance (actually, potentially multiplying the distance by 5). Then you move up the layer stack and guess what? More bi-directional communication at each layer (there are 7 layers, we haven't talked about the session, presentation, and application layers at all). And let's remember too that when you send a message to grandma's house 3 miles away, the actual phyical paths that a message travels could be anywhere between 5 miles and 700 miles or more. If each layer multiplies the travel distance of a signal by 5, you are now at 39,420.5 km travelled. Yeah, that's a tenth of a second, but that's only the first transmission. Now that connectivity is established each consecutive communication has less distance to travel and all of those devices along the way can work faster now that they've worked things out. Still, all of those devices have work to do and the more devices (and the less clear the signal to those devices) the more work has to get done. But that's not really the amazing thing. A signal isn't travelling at all. No single electron makes it's way from one end of the pathway to another. What you've done is told one electron to dance, and it's told it's nearest neighbor to dance as well. And so on and so forth. Consider that there are 3 trillion atoms in a spec of dust. And of course there are several electrons in each atom. Lay that out end to end over tens of thousands of kilometers and you have interacted with a number of atomic particles that you cannot even fathom. All by pushing a button on a keyboard. And we live in the one special place in the universe with the right temperature, the right combination of elements, the right amount of gravity, the right amount of everything that makes it possible for you to cause all of those little pieces of universe to bend to your will as if you were waving a streamer like a gymnast. And you live in the one special place in the universe where life was generated intelligent enough to figure all that was necessary to build this structure out AND had the motivation to do it. Billions upon billions of cubic miles of nothingness and your particles just happened to end up in the right spot so YOUR BRAIN could make the decision to tell the other person on the XBox Network \"you are a good shot!\" It's very much a miracle that any of this happens at all. One little blip. One meteorite that hits at a different time or at a different angle at the right time in history and we're all bits of moon rock desperately trying to stay still and do nothing. Or you know... some other reason. I don't really know for sure.", "It's also noteworthy that the speed of light isn't the same in every material. Optical fibers lower the speed by a decent percentage (~30%), and many common copper data cables (cat 5/6) can be even worse. See URL_0 Interestingly, optical fibers _wouldn't work_ if the speed of light in them wasn't significantly lower than the speed of light in air/vacuum.", "The latency comes more from the various bits of hardware the signal has to pass through, than from the wires. Even so, if you're going halfway around the world at the speed of light without detours, that's 20,000 km / 300,000 km/s = 66 ms (edit: in each direction, so the ping time would be +133 just from distance) which is already a pretty respectable ping time.", "For the same reason it takes only 4-5 hours to fly from Los Angeles to Chicago, but you can sit there waiting for a connecting flight in Denver for 4 more hours if there's no directs available.", "The other answers deal with why latency exists, but I would like to add that electricity does not travel at the speed of light through a vacuum, through wiring. It's varies from 50-99% of that. Still extremely fast, so the limiting factor is still computers receiving, retransmitting, and calculating and all that. Now if satellite is brought in to the picture anywhere, there's actually a lag solely because of the travel time to and from the satellite. Not a problem for most connections, but those with satellite internet can't avoid a minimum lag from that.", "First of all, the electrons making up electricity do not move at that speed. They absolutely CRAWL along. You are talking about the speed of energy transmission, a bit like a line of billiard balls. The balls tap the one ahead and the energy moves forward. OK, not a perfect analogy, but enough to get the gist. If it were only just the transmission of the initial energy that reached it's destination, then you could measure the distance and using the speed, work out the time involved. BUT..... as others have described, there's a lot of crap going on during the journey and it is THAT which slows everything down.", "Lets think about what you said. You say that electricity travels at 300,000 km/s and you seem to be suggesting that if that's so fast it shouldn't effect internet speeds. Internet speeds (ping) are measured in milliseconds (ms), so sending a data packet 300,000km would be 1000ms and 300km would be 1ms, which is pretty quick.", "Ping is just no a single light that is bounced back. It's certain types of packets that are processed and forwarded by routers. There are no single long cables between all the computers, but many central hubs where a huge portion of the traffic travels. For example there are only couple of connections across the atlantic. Every time a packet is received at the router, it is in a queue and eventually processed. This adds up with long distances.", "Questions like this allow me to feel confident in my job Security. My parents told me the next generation of children will all be computer whizzes so I better study hard because they are born with devices and master them. Today I realize just because a lot of people know how to drive it doesn\u2019t mean they know how a modern internal combustion engine works.", "One part of the problem is, the speed of light is 300,000 km/s **through a vaccum**, such as outerspace. The speed of light drops when going through a medium (e.g. Water, atmosphere, fiber optic cables, copper cables)", "ping \u2260 propagation delay. The latency experienced is composed of many different components. Processing delays at different network layers are accumulated. Of course if you compare a satellite link to optical fibre connection you will see a massive difference as the physical layer latency of a sat link is larger an order of magnitude. Routing and forwarding delays are a significant factor. To experiment, traceroute different countries that are geographically close but use different routes. Traceroute will show you the route and corresponding delays. If you are in Europe for insance compare pings of two websites from Iran and Japan. You will see the effect of physical length of the cables might be superseded by topology of the network in some cases.", "-The circumference of earth is 40075km. -The speed of light is 300,000km/s. Let\u2019s say you set up a light fiber directly for two locations between the earth without any other router. The light needs 0.1335 secs to travel there and back, or 133.5ms. That\u2019s too ideal and signal will be weak without enhancement, weak signal will make lots of errors. That\u2019s the physical barrier we can\u2019t breach unless we can control something faster than light. Communication between computers is not simply \u2018hello\u2019-\u2018goodbye\u2019, computer still needs to think and check, it\u2019s more like: -\u2018I have send 50 encrypted packages to you and some might got stuck in a crowded server at France, please check up\u2019 -\u2018Ok ummm, who are you again? Ok I\u2019m decoding, I got it and I checked there are 49 of them, please send the #29 again\u2019 So that will take some time. All added up, you can expect 10ms read messages, but light in fibers travel in 0.7 light speed, that will take 190ms. It\u2019s 200ms, The real latency is around this. You see, no matter how fast you can read and how servers getting better, the latency will always be there, mostly the light is still not fast enough."], "text_urls": [["https://physics.stackexchange.com/questions/80043/how-fast-does-light-travel-through-a-fibre-optic-cable"], [], ["https://en.m.wikipedia.org/wiki/Velocity_factor"], [], [], [], [], [], [], [], [], [], []], "score": [1830, 743, 162, 75, 21, 19, 9, 8, 7, 5, 3, 3, 3]}}, {"q_id": "76i668", "category": "Repost", "title": "why is there this thorny thing on my ice cube?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["doe6osx"], "text": ["they are called ice spikes im sorry I can't explain it myself, but this video will definitely do URL_0"], "text_urls": [["https://youtu.be/5RLQ9WMP2Es"]], "score": [3]}}, {"q_id": "76idf1", "category": "Repost", "title": "How come in English we capitalise the word \u201cI\u201d but don\u2019t do so for \u201ca\u201d or other personal pronouns such as \u201cyou\u201d?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["doe8a5f"], "text": ["According to [ URL_1 ]( URL_0 ) it used to be lowercase. Then, people started writing it a little bigger likely because it looked funny all on its own. Eventually, people started to capitalize it."], "text_urls": [["http://www.dictionary.com/e/whycapitali/", "dictionary.com"]], "score": [3]}}, {"q_id": "76jq5h", "category": "Repost", "title": "why is it when we yawn sometimes we start to get teary?", "title_urls": {"url": []}, "selftext": "What's the connection?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["doeh86z"], "text": ["Because when you yawn your faces scrunches up and squeezes your tear ducts which are also installed in your face."], "text_urls": [[]], "score": [5]}}, {"q_id": "76jzx3", "category": "Repost", "title": "Does every single car in the world have a unique key?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["doeiql2", "doejl7q", "doerba7", "doerrh8", "doesc6f", "doepu7e"], "text": ["> Does every single car in the world have a unique key? No. There are too many cars and too few combinations. It is possible for the coded chips to have a truly unique combination but the physical keys are reused.", "No they don't GM used to only have about 50 different unique key cuts and about 10 resistor values within the keys. So thats not that many unique combinations. (500) Honda had a key until quite recently with 8! Different keys which worked out about 40,000 different keys but they made about 4,500,000 cars in a year so there were a lot of identical keys.", "I had a 1977ish Mercury Monarch that had the same key as my Dad's brand new 1986ish Ford LTD", "No, they repeat keys. My sister and I accidentally stole someone's car after we had just had an argument with the person. Her key worked to open and start the car. I think they were both 99' Toyota Camrys. We figured out a couple miles down the road when we noticed a backpack in the back seat and went straight back. He had called the cops on her and they just laughed it off.", "All international trucks use the same exact key. We have several in our fleet and we all just have a key and it works any truck, including the rentals we occasionally get.", "I accidentally opened up another rx7 one day. Don't know the maths, but the random occurrence made me think there shouldn't be too many of those \ud83d\udd11"], "text_urls": [[], [], [], [], [], []], "score": [28, 21, 6, 6, 4, 3]}}, {"q_id": "76nddv", "category": "Repost", "title": "Why does our voice sound different to us than to other people?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dofbmfr"], "text": ["I'll type fast because your post will be removed. Your voice is carried by your skull bones to your ear. Skull bones carry sound a little differently."], "text_urls": [[]], "score": [8]}}, {"q_id": "76ppys", "category": "Repost", "title": "How did colonists communicate with natives of the country", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dofs70k", "dofso0l"], "text": ["They start with the basics. For example, Antonio Pigafetta, an Italian who travelled with Magellan, interviewed members of several indigenous peoples that the expedition encountered. Using gestures and pointing, he would prompt them to tell him their languages' words for simple concrete objects - \"sun\", \"leg\"', etc. - so that he could write them down, and then (at least in a few instances) gradually work up to more abstract words. Exchanges like these in other times and places enabled some people from both populations to learn the other group's language well enough to serve as interpreters and laid the groundwork for more intensive studies of indigenous languages later on.", "Gestures and actions, mainly, until some people started to understand the language well enough to start communicating that way. It's perfectly possible to learn a language without any help from dictionaries, vocabulary lists and grammar books, and the living proof of that is literally every single person on earth. Everyone was born without knowing a single language, but you learned it just through exposure. As long as the people are willing to try and communicate with each other, they will eventually be able to understand."], "text_urls": [[], []], "score": [4, 3]}}, {"q_id": "76r9y8", "category": "Repost", "title": "why did the sky in NE England go dark for about 20 mins this afternoon?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dog30cr"], "text": ["Storm Ophelia has picked up lots of dust from the African desert and it's all blowing around in the sky. URL_0"], "text_urls": [["https://www.standard.co.uk/news/uk/london-sky-cloaked-in-strange-orange-glow-in-storm-ophelia-dust-phenomenon-a3659886.html"]], "score": [3]}}, {"q_id": "76rswn", "category": "Repost", "title": "why can\u2019t your Download/Upload be the same speed?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dog6yzj", "dog6y8i", "dog734p"], "text": ["It can, and for commercial internet connections they often are. Those are symmetrical connections. But most home users download far more than they upload, so the connections are skewed to reflect that. These are asymmetrical connections. If you have 20 Mb down and 2 Mb up, you may be thinking that \"hey, I'm getting robbed of 18 Mb upload speed\". That's not it at all -- you have a 22 Mb connection, and instead of getting 11 Mb down and 11 Mb up, it's configured to give a (far more useful to most people) 20 Mb down and 2 Mb up.", "It definitely *can* be. Here are a couple reasons why there may not be: * Your ISP limits your upload to prevent congestion and misuse of their network. * Your computer may not be capable of sending out data as quickly as it can receive it.", "Most internet connections can be thought of as a highway with multiple lanes. You can have each lane going whichever direction you want, but you can't have cars (data) travelling in different directions on the same lane. ISPs realized that people download a lot more than they upload, so they made most of these lanes be download lanes."], "text_urls": [[], [], []], "score": [10, 3, 3]}}, {"q_id": "76zdfc", "category": "Repost", "title": "If a toy drone was hovering in a train carriage, would it hit the back wall when the train started moving, or would it stay in the same spot?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dohrxw1"], "text": ["While the train is accelerating, the drone will lurch backwards toward the back of the train. Once the train reaches constant velocity, the drone will stop moving (relative to the train)."], "text_urls": [[]], "score": [3]}}, {"q_id": "76zm1k", "category": "Repost", "title": "Why do most species have breeding seasons but humans don't?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dohuc65", "dohuf3h", "dohyzqd", "dohwrqb"], "text": ["This is because in their environment, there are only a few times a year that \"allow for the optimization of survival of young due to factors such as ambient temperature, food and water availability, and changes in the predation behaviors of other species\" There is no special month that makes it better or worse for humans. We have no predators, and food + water is available all year round.", "Most humans and their relatives (apes) don't have a specific mating season. The climate the apes live in doesn't really have drastically different seasons with varying levels of food availability, which often dictates other animals mating seasons. On top of that sex and mating are integral to primate social dynamics, especially with humans, Bonobos, and Chimps. Lastly humans and Apes have some pretty damn long infancy spans, meaning no matter what you're gonna have to take care of offspring throughout the year anyway.", "We do. Its called Christmas break. Ever wonder why all kids have birthdays in late August to October these days?", "Humans evolved in the tropics, so it didn't matter what time of year you had children. One month was as good as the next. Animals that evolved in more temperate regions had to time their births so that their children were able to survive the winter."], "text_urls": [[], [], [], []], "score": [20, 13, 5, 3]}}, {"q_id": "7754dt", "category": "Repost", "title": "Why do horses wear shoes if wild horses don't?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["doj400j", "doj61t1"], "text": ["URL_0 > Many changes brought about by the domestication of the horse have led to a need for shoes for numerous reasons, mostly linked to management that results in horses' hooves hardening less and being more vulnerable to injury. In the wild, a horse may travel up to 50 miles per day to obtain adequate forage. While horses in the wild cover large areas of terrain, they usually do so at relatively slow speeds, unless being chased by a predator.[4] They also tend to live in arid steppe climates. The consequence of slow but nonstop travel in a dry climate is that horses' feet are naturally worn to a small, smooth, even and hard state. The continual stimulation of the sole of the foot keeps it thick and hard. However, in domestication, the ways horses are used differ from what they would encounter in their natural environment. Domesticated horses are brought to colder and wetter areas than their ancestral habitat. These softer and heavier soils soften the hooves and make them prone to splitting, making hoof protection necessary.[4] Consequently, it was in northern Europe that the nailed horseshoe arose in its modern form. > Domesticated horses are also subject to inconsistent movement between stabling and work; they must carry or pull additional weight, and in modern times, they are often kept and worked on very soft footing, such as irrigated land, arena footing, or stall bedding. In some cases, management is also inadequate. The hooves of horses that are kept in stalls or small turnouts, even when cleaned adequately, are exposed to more moisture than would be encountered in the wild, as well as to ammonia from urine. The hoof capsule is mostly made from keratin, a protein, and is weakened by this exposure, becoming even more fragile and soft. Shoes do not prevent or reduce damage from moisture and ammonia exposure. Rather, they protect already weakened hooves. Further, without the natural conditioning factors present in the wild, the feet of horses grow overly large and long unless trimmed regularly. Hence, protection from rocks, pebbles, and hard, uneven surfaces is lacking. A balanced diet with proper nutrition also is a factor. Without these precautions, cracks in overgrown and overly brittle hoof walls are a danger, as is bruising of the soft tissues within the foot because of inadequately thick and hard sole material.", "Horses in the wild don't carry heavy loads, and aren't asked to traverse rocks and pavement. URL_0"], "text_urls": [["https://en.wikipedia.org/wiki/Horseshoe"], ["https://www.reddit.com/r/explainlikeimfive/comments/227udt/eli5why_do_we_put_horse_shoes_on_horses_when_in/"]], "score": [24, 3]}}, {"q_id": "7754gb", "category": "Repost", "title": "Why haven't we yet found a cure for HIV/Aids", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["doj4lk3", "doj72zb", "doj6ivj", "doj7efe", "doj6rgs", "doj4pus", "dojd6uy", "doj7a6i", "doj5qhm", "dojgm2x", "doj6uh7", "doj6ym0", "doj8coj", "dojaz5n"], "text": ["As I understand it: HIV\u2019s genome is made of RNA. In order to infect human genomes, it has to first be transcribed into DNA. It accomplishes this via a protein called \u201creverse transcriptase.\u201d Reverse transcriptase has a very high error rate. It makes a lot of mistakes. Because of the high rate of errors and the high rate of reproduction of HIV-infected cells, there\u2019s a lot of mutations that are different but still functional. That means that HIV has a lot of opportunity to mutate in a way that makes our treatments no longer effective. That\u2019s why most AIDS patients are on what they refer to as a \u201ccocktail.\u201d It\u2019s not just one treatment. It\u2019s like 5 or 6. So if their particular strain starts to develop an immunity to treatment A, they\u2019re still affected by treatments B through E. That said, there technically is a \u201ccure\u201d for it. A small subset of the population has a natural immunity to HIV. Their immune cells aren\u2019t susceptible to infection by HIV. By chance (I think), one of those people donated bone marrow to someone who was HIV positive. Bone marrow is the place in your body that makes immune cells. The donated marrow began producing HIV-resistant immune cells. Eventually, the patient was AIDS-free. However, bone marrow transplants are very dangerous and risky, and have high rates of failure and/or patient death from complications. So while there is technically a cure, it\u2019s not a very useful or viable cure. It\u2019s not terribly worth it considering that the HIV treatment cocktail has become very good and effective and most HIV patients live longer and have a better quality of life compared to bone marrow transplant recipients.", "I'm seeing many comments on here that diseases are kept infectious because they're 'profitable.' Please take off the tin foil hat. I am a medical research scientist and I can tell you, the massively talented team I'm in work extremely hard to combat illness and improve survival rate. Sure, unfortunately some treatments for illnesses are not manufactured. This is due to a cost-benefit analysis of the medication. A costly to produce treatment for an uncommon illness, or treatment that may not be hugely successful or it doesn't improve survival rates much, will not be marketed. Even if there is some evidence it works. Unfortunately that's the way of it. Whenever we get the red light on a product line, we all think 'but if my mum had this illness...and companies have shelved a cure...' But we need to move on and focus on a treatment for an illness that's extremely common: HIV/cancer for example. Not only would this net massive profits for the company that have put in sometimes hundreds of millions into R & D, but it will save, or improve, countless lives. If we produced medication at a loss, we'd go out of business. And then there'd be no more cures for anything. The cost of medical isn't the cost of producing it, that pales in comparison to the cost of developing and approving it. Recently we did an animal trial on 3 pigs. The cost? 1.8million GBP. To show something we already knew. Add that on top of a 3 year project which has already cost in excess of 30million and you'll see where the cost comes from. And if this product doesn't make it to market, the losses also have to be recouped from somewhere. I.e. Another product line.", "Thanks for the answers everyone. Very informative and a great read! :-) I've heard that most people with HIV can live relatively normal lives thanks to the development of drugs in this field. In fact, I think I remember reading that the levels of HIV in the blood of positive people is so low that it's virtually impossible to pass it on. Is this true?", "First, the distinction between HIV and AIDS. HIV (human immunodeficiency virus) is the virus that is transmitted between people and that causes AIDS. HIV likes to infect immune cells (or certain types of immune cells), which are the cells that are called to action to get rid of (or clear/resolve) an infection of any kind. AIDS (acquired immune deficiency syndrome) is a set of rare/unusual diseases that can occur in HIV-infected individual when the HIV virus has destroyed a certain amount of immune cells. AIDS is pretty preventable, if using the right medications. Most people with HIV can avoid progressing to AIDS if they're taking the right medicines and if they're taking their medicine properly. [This is thanks to antiretroviral therapy (ART)]( URL_0 ). So far, HIV itself can be controlled but not cured. A lot of commenters have touched on important aspects of HIV that make it hard to fight. However, it is important to note that HIV, as a retrovirus, integrates into the genome of the cells it infects. What this means is that once it gets into a cell, HIV takes its genome and puts it into the genome of the cell it is infecting. This means that, for that particular cell, HIV is now part of the DNA of the person. (This only happens in infected cells and it does not happen to \"germline\" cells, so you can't 'inherit' HIV in the way you would inherit, e.g., eye colour). This is different from other non-retroviral viruses, which by-and-large remain outside of the host genome. It is currently very hard (read: impossible) for any methods we have to determine which cells have this little HIV stowaway and which ones don't. This is all aggravated by HIV's preference for certain immune cells. Essentially, the cells that are responsible for clearing viruses are the targets of HIV infection. This is bad at first because when an HIV infection starts, these cells rush to the site of infection to try to limit the spread - and this ends up making it worse. As time goes on, HIV destroys these immune cells; this weakens the immune system so that it becomes unable to protect the body against HIV (and, in the context of AIDS, it becomes unable to protect the body against all sorts of things that immunocompetent people never have to worry about). The answers provided by /u/wittymcusername and /u/burhunk are also important, but I think you should also keep in mind that HIV isn't like a lot of other viruses - once it is inside a cell, it becomes essentially indistinguishable from the host by inserting its genome into the host's genome. The [person cured of HIV]( URL_3 ) that was mentioned by /u/wittymcusername was only cured because his immune cells (in which HIV lives) were destroyed (by radio/chemotherap) for the stem cell transplant he received ([because he had acute myeloid leukemia]( URL_1 )). I don't think this would ever be done in the case of an HIV+ patient that does not have acute myeloid leukemia because radio/chemotherapy for cancers are very damaging in themselves. Also, this man was lucky to be compatible to someone with an HIV-resistance - not everyone could have received stem cells from this donor. Even if you did want to use this as a \"cure\", you would need a lot more donors with the HIV-resistance phenotype (called \"delta 32\") than there actually are. If it makes you feel better, there are hardly any cures for any viral diseases ([Hepatitis C]( URL_2 ) is the only one I can think of off the top of my head; maybe rabies, although I'm not sure whether to count it as a cure). Most resolve on their own (by the action of the immune system), or never resolve. Some of these viruses do infect immune cells, but are different because they do not integrate into the genomes of these cells like HIV does. Vaccines are usually the best approach to combat viruses. They are not a cure exactly, but they prevent an infection from happening in the first place. Why *vaccines* don't work for HIV (so far) is a different story - this relates more to what other commenters are saying about high error rates and a disguised shell (/u/Its_just_a_Prank-bro). Basically, HIV changes too quickly for vaccines to keep up. This is superficially similar to how you need to get a different Flu vaccine every year. Edits: removed an extra period and corrected \"Acquired immunodeficiency syndrome\" to \"Acquired immune deficiency syndrome\" (thanks /u/jeffbaier)", "Great question! To put it simply: When HIV infects a new cell and inserts its genetic material into the cell\u2019s DNA, it has two choices. It can start making more viruses right away (this is what happens the majority of the time) or it can choose the sneaky option. The sneaky option is to do nothing. Inhibitors (HIV treatment) can find cells making HIV and stop them, but they can\u2019t do anything when a cell\u2019s only sign of being infected is a little bit of virus DNA. These cells that have the virus DNA that aren\u2019t actively making new virus are the latent cells Someone with HIV who takes a few doses of inhibitors and stops might be fine for a while, but eventually the latent cells in their bodies will become active and start making virus. Then they\u2019ll get sick all over again. This life-long cycle of inhibitors is the only way to keep HIV in check until scientists can find a way to kill latent cells before they ever start making HIV. With a combination of inhibitors and drugs that target latent cells, we\u2019ll have a cure.", "HIV is a virus that damages a person's immune system and kills their white blood cells, allowing simple diseases or infections to become deadly. AIDS is a syndrome diagnosed when you have a low enough white blood cell count. Viruses like HIV aren't living beings like bacteria, and don't need special conditions and \"food\" to live, they are just packets of DNA that inject themselves into human cells and try to reproduce and sometimes cause problems. Because they are so simple, viruses can evolve and mutate very fast meaning drugs which can kill them stop working very fast. Since viruses lock onto cells it is currently impossible to hurt the viruses without damaging the host's body as well. That goes for any virus, although some are more dangerous than others. Medicines today only control the symptoms the virus causes, and cannot permanently kill the virus itself. Some viruses have vaccines that train your body to fight the virus so that if you were to become infected, your body would instantly know how to kill the virus before it can spread and mutate.", "I'm an HIV vaccine researcher. /u/wittymcusername does a great job of identifying some of the challenges involved with HIV cure research. But that's only part of the picture. Here is every reason I can think of. **Viral Escape.** As described by /u/wittymcusername, HIV has a high mutation rate. In addition to changing the proteins that make up the individual virions, the virus has a coat of sugar-like molecules called glycans that essentially shield the virus protein from being targetted. Every time your body comes up with some way to shut the virus down, some of the HIV in your body reacts by changing these glycans. This is like if the Police say they are looking for a suspect wearing a bunny mask, then the criminals take off their bunny masks and instead dawn tiger masks. **Immune Targetting.** HIV is especially problematic because unlike most infections, it specifically targets immune cells. Imagine an organized crime ring: You have enforcing agents who go around gathering \"protection\" money from businesses, drug dealers, etc... but also crooked cops who have been convinced to help the criminals instead of the people. HIV effectively turns good cops bad by making them stop working well. This is especially problematic because the cells HIV infects are responsible for major immune decisions, including the \"internal affairs\" units. Essentially, the only way to get rid of these bad agents is to eliminate all of them and replenish from an uncorrupted source. So far, we've accomplished this once, which I'll mention how in a little bit. **Viral Reservoirs** are the hardest modern challenge facing current cure efforts. Viral escape, mentioned earlier, creates entirely new infectious HIV. But it also creates non-replicative HIV sleeper cells: some mutant HIV viruses insert their genetic code into host cells in odd places. The cell doesn't seem to be infected until one day, it gets an atypical but normal signal and **BOOM!** it starts spewing out fresh HIV viruses. Because the cell is not making HIV proteins, it is nearly impossible to target... Thus it serves as a reservoir for restoring HIV should the active virus be eliminated in the future. This is the major focus of current cure research: It may sound scary, but the goal to figure out how to safely reactivate these reservoirs so that the secretly infected cells can be eliminated. It may be high risk as well, but the hope is that we can manage to eliminate it effectively. **We have cured one person.** Timothy Ray Brown, aka *The Berlin Patient* is considered HIV negative and takes no anti-HIV drugs anymore because he is believed to be cured of HIV. This happened because he had cancer. Brown recieved Chemo, Radiation, and a Bone Marrow transplant in addition to HIV treatment. When he finished having his cancer treated and cured, he was tested for HIV and found to be negative for it. For the Police/Criminal metaphor, this would be like killing all the Police seargeants, burning the Police Academy to the ground, and building a new academy. Brown has to take medication to keep his transplant healthy, but HIV medication isn't part of it.", "There's a lot of great answers on why, and a lot of them refer to its high mutation rate. This is a factor in finding medicines that work against it. The reason we can't really cure it is because it becomes a part of you once it infects you. First to understand how the virus works: URL_2 To talk you through the video if you do not understand it: first there is a detailed description of how the HIV virus particle enters the cell. This is not extremely relevant but it is interesting. Then it goes on about how the RNA (the genetic information of the HIV virion) becomes DNA (which is the 'format' of genetic information our cells use in their nucleus). A lot of errors are made in this step, which is why the virus is constantly evolving. Next what you see is that the Virus' genetic information becomes a part of our own genome, i.e. it becomes an unseperable part of the cell it has infected. Once it is in there, it is not going to get removed again. It stays there for the rest of the cell's lifetime. It then can start producing new virus particles. It doesn't necessarily do this directly. It could do so immediately, or it might wait a few months or even years before it starts this process. This means that you may be infected without any way of knowing (but during this time you are probably not going to be able to infect other people, unless there are other infected cells which are producing HIV particles of course). The only way to completely cure a person from HIV is to either kill all the cells that have been infected, or remove the genetic material from those cells. The former is really difficult, because you will just kill the entire immune system of the infected person, and there is no way of being sure that there are no infected cells left, so it is not a realistic option. The latter is really also impossible at the moment. First of all, even if we could, we would not be allowed to, since we are not allowed to genetically modify people. Secondly, we don't have the means of transporting the proteins capable of doing so into the target cells (and the target cells only). Some people are looking towards CRISPR/CAS9 as a possible solution to this problem, but perhaps it might be more realistic at a current stage to look for people who are immune to HIV because of a certain mutation (although there is no way of telling how soon the virus will then evolve to be able to infect those people as well). Some more material for understanding HIV that is really easy to understand: URL_1 URL_0 Disclaimer: I am not a specialist in this field, I'm just a humble biology student, so anyone who knows better, please feel free to correct me.", "Well the easy answer without too much complex terms is that HIV is a virus, which means it can very easily change the properties of it's shell. So that would be like putting on a disguise so that the white blood cells can't detect it, and doesn't know how to combat it. And the other reason is that it directly attacks the white blood cells so the body can't even fight back if it wanted, this is AIDS part which is the autoimmune deficiency syndrome, so not only the body cannot attack the HIV but also any other disease which is worst part", "Wow! Can't believe this is still going. It's going to take me a while to read through all these posts but a massive thanks to everyone for posting, even the more controversial posts.", "There are a few reasons. 1. HIV is a *retrovirus*. Retroviruses have a single strand of RNA instead of double-helix DNA, like we have. RNA is less stable than DNA and easier to break, which means that retroviruses mutate and adapt very quickly. Even if you developed a drug that could cure it, a new strain would soon appear that is immune to your drug. Even vaccines only help against the current strain, and they only work if you get them before being infected. Other retroviruses include the cold and the flu, which don't have proper cures either - of course, these illnesses are less serious than HIV, because a healthy immune system can fight them off without a need for drugs (it can do this because the immune system, like the virus itself, is capable of adapting quickly basically by *trying everything* and \"seeing what sticks\" - unlike drugs, which must be developed and tested by humans, who are much slower). Which brings us to the second point... 2. HIV targets the immune system itself. Almost every drug we have is only there to give the body's immune system an \"edge\" in the fight; exterminating every last virus in the body is pretty much impossible - we rely on the immune system to clean up the survivors. Unfortunately, once HIV gets a foothold in the body the immune system can't fight it effectively, because white blood cells are the cells that the virus *targets* to reproduce. So to really cure HIV, you'd need to kill *every single virus*. Cancer has a similar issue (except in cancer's case, the problem is that the body doesn't recognize it as dangerous, so unless you kill every single cell it will grow back).", "HIV does not just copy itself cells, it inserts itself into their DNA. For those cells it succesfully infects, it becomes a part of who you are. Medications can stop it from growing, and help you live a long life, but they can never take it out of your DNA. If you stop taking your pills, the virus will come back. Not only that, but when HIV mutates itself faster than almost any organism we know. This allows it to quickly develop resistance to drugs, unless you are on so many drugs at the same time that the virus is unlikely to mutate resistance to all of them at once. While some scientists are working on a way to cut the HIV out of people's DNA, we do technically have a cure, but it is very expensive and dangerous. You have to kill all your white blood cells, where HIV hides, then replace them with cells from someone who can't be infected with HIV.", "To all those believing we don't invest in finding cures because it's more profitable to treat a patient for life: Look at Gilead. They created a CURE for hepatitis C recently. It's 99% effective with minimal side effects. They made over $12 billion in a single year curing people. The older medicines that weren't as effective were withdrawn from the market. There's definitely money in a cure. They are just really difficult to make. Also, we've only known about HIV/AIDS since the 80s. To have the medicines we have today that are so effective in such a relatively short amount of time is nothing short of amazing.", "So normal cells have an error checking mechanism to keep error rates at roughly one in a trillion. HIV has an enzyme called reverse transcriptase. Basically, it makes DNA from RNA, and when the virus is inside a cell, it becomes a part of its DNA. Now the virus doesn't have any error checking of any kind. So it goes through the replication process unchecked, and if the virus makes any sort or errors or mistakes, it just rolls with it. It does this at such a rapid pace, that it can never stay stable enough to develop a cure for it. So to quote Q from Skyfall, \"It's like solving a Rubik's Cube that's fighting back\"."], "text_urls": [[], [], [], ["http://www.aidsmap.com/Life-expectancy-near-normal-in-people-with-CD4-counts-over-350-a-year-after-starting-therapy/page/3142626/", "https://www.cancer.org/cancer/acute-myeloid-leukemia/treating/bone-marrow-stem-cell-transplant.html", "https://www.webmd.com/hepatitis/features/cure#1", "https://en.wikipedia.org/wiki/The_Berlin_Patient"], [], [], [], ["https://www.youtube.com/watch?v=0TipTogQT3E", "https://www.youtube.com/watch?v=FDVNdn0CvKI", "https://www.youtube.com/watch?v=odRyv7V8LAE"], [], [], [], [], [], []], "score": [4270, 1094, 864, 338, 53, 29, 17, 12, 11, 9, 9, 7, 5, 3]}}, {"q_id": "776otm", "category": "Repost", "title": "How did people book plane tickets before the internet and phones?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dojelmi"], "text": ["Phones were invented before planes were, so by the time commercial plane traffic was a thing, telephones had already proliferated. There were also things called Travel Agencies. They're still around, but not used as they much as they used to be. You'd call them, tell them where you wanted to go and when, and they'd make all the arrangements for you."], "text_urls": [[]], "score": [3]}}, {"q_id": "779z8k", "category": "Repost", "title": "Why is it that Nagasaki/Hiroshima were safe weeks after the explosion but Chernobyl won't be for thousands of years?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dok6k5b", "dok8nsk"], "text": ["The bombs had orders of magnitude less radioactive material, and they were detonated in the air, thus spreading the material wide and largely into the wind. As a result, the region recovered quickly as the radiation was dispersed. In contrast, Chernobyl had significantly more radioactive material and melted, combining it with steel and dirt, resulting in a sludge of very highly radioactive material. It solidified into the infamous \"elephant's foot\" that is so radioactive that people can't be in the same room as it without high risk.", "Hiroshima was an air burst of 140 lbs of U-235 in a gun-type arrangement. The weapon was detonated at ~1,800' above the ground and this greatly reduced the amount of neutron activation in fallout debris lifted in the updraft that you would get from a ground burst. This means this small amount of radioactive material is the principle component spread across a ~4 mile radius. Approximately 2% of the uranium was fissioned in the detonation. Uranium has a long half life, over 4 billion years. This means it's pretty stable, and the rate of decay is actually pretty slow. Depleted uranium, U-238, is used as an anti-tank projectile and handled with bare hands. Thorium can be bought in any quantity from any welding supplier. The neutron activated products and some of the radioactive byproducts from radioactive decay have a much shorter half life, so they're hot, they're active, they're dangerous because they're dosing quite a bit over a short time, and the material spread so thin, it cools off relatively quickly. Chernobyl reactor 4 had 210 tons of radioactive fuel in it, and it was emitting fire, steam, and gasses for over a week. It contaminated the ground water, which spread into the surrounding environment, and it kept on leaking. Chernobyl released ~400x radioactive material into the atmosphere than Hiroshima, and a number of radioactive products not seen in significant quantities from the nuclear weapon. With Chernobyl, it's the amount of material in the environment, despite their longer half-lives, at this point, that makes the whole area so dangerous. > Why can't it be cleaned? How? It's not like there is visible radioactive bits that can be swept up. Think atomic sized dust. You would have to strip the whole landscape bare, like a strip mine. You would have to follow all the contaminated ground water paths. You would have to ensure the material removed doesn't leave containment and that the cleaned area doesn't itself get re-contaminated. The logistics are simply unfathomable."], "text_urls": [[], []], "score": [19, 5]}}, {"q_id": "77aaik", "category": "Repost", "title": "Why does India have so many people?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["doka3po", "dokakpn", "dokdroi"], "text": ["The poorer part of India is against birth control, breeds until they have enough men to sustain the family, because once you're old you're supported by your children, and other cultural reasons that promote large families.", "In addition to the history of ideal conditions for population growth, appears to me like a cultural issue as well. It's a culture in which men are controlling and women have no say in family planning. This is why in developed nations where gender equality is more pronounced and women have more autonomy, the rates of births will decrease.", "I am an Indian and will try to explain from my understanding of our history. 1.Indians totally value family above all else. So the concept of an only child is pretty rare. 2.Historically India was many many kingdoms constantly at war with each other. It was not till 200 years back that wars reduced. So it was common for couples to have many children as many would die. 3.Improved health care is definitely a contributor. 4.Lack of education. Poorer classes still believe their sons would be able to support them."], "text_urls": [[], [], []], "score": [11, 9, 4]}}, {"q_id": "77ako0", "category": "Repost", "title": "How do courtroom stenographers record everything that is said accurately?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["doke0s8", "dokb0qm"], "text": ["Yes, I do this for a living (transcription, not stenography)! I can answer this question! xD Okay, so you've got two types transcription: stenography and regular keyboard transcription. Stenographers essentially use a phonetic keyboard. They can type an entire word by simultaneously pressing multiple keys on their board, much like a pianist playing multiple notes to make a chord. Because each word only takes one press, it's very easy to keep up with the pace of someone's speech if you've been trained to use a stenotype. They're more frequently used in running trials and civil cases where the counsel for the parties needs a running transcript of the proceedings as soon as humanly possible. It takes a lot of training to become a stenographer and they're becoming increasingly more rare. The large bulk of transcripts (in Australia) are now performed by keyboard typists. When needed to do real-time transcription, they work in groups of two to three, on alternating blocks of audio that they can pause and rewind.", "They use a shorthand keyboard called a stenotype. It's missing some letters like C because it can be replaced with an S or a K, so you don't have to use as many letters."], "text_urls": [[], []], "score": [4, 3]}}, {"q_id": "77cmru", "category": "Repost", "title": "How the hell do speakers create sound? How is something that vibrates able to recreate entire orchestras and audiences clapping?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["doksxqf"], "text": ["First, remember that all sound is just vibrations in the air that hit our ears. They're very specific vibrations, but vibrations nonetheless. Speakers work VIA magnets, specifically electromagnets interacting with traditional magnets. So when you run an electrical current through a coil of wire, you produce a magnetic field. This is the basis of electromagnets; Speakers work by having an electromagnet coil attached to a thin membrane, and then a little bit away having a static magnet. Electromagnets have alternating polarity of the magnets, while static magnets have, well, a static north pole and south pole. So as the current flows through the wire, it alternates the north and south poles, creating attraction and repulsion forces *very* quickly. The signal changes based on the sound that is trying to be played through, but here's the genius: a microphone and a speaker are basically the same thing. Much like running an electrical speaker through a coil of wire will produce a magnetic field, moving coils of wire around a magnetic field will produce an electrical charge. So a microphone picks up sound waves through the thin membrane, which moves a coil of wire around a magnet, and sends that electrical signal to a computer (or something, but these days it's a computer) that can store the electrical data that is sent out. Then when the recording is played back, it sends that electrical signal out to the speakers, which creates a magnetic field which moves the thin membrane to push air in proper sound waves."], "text_urls": [[]], "score": [4]}}, {"q_id": "77dzjs", "category": "Repost", "title": "How does Einstein's theory of relativity work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dol24gw"], "text": ["Here is how I think about it. We have two conflicting rules: 1) Nothing can move faster than the speed of light; and 2) For every action, there is an equal and opposite reaction (which mathematically is expressed as Force = Mass X Acceleration) If you are traveling in a spaceship going just under the speed of light, say 0.9999999999999% this doesn't break rule 1 or 2. No problem. But then say you throw a sofa out of the back of your spaceship. Rule 2 says you should speed up. But rule 1 says you can't. So the universe cheats. Force = Mass X Acceleration has, as its basic units, Force, Mass, Distance, Time. To preserve Rule 1, the universe starts to mess with Mass, and Time. It slows time down in fact, and the faster you are going, the slower time goes. In fact, when you really are going at 0.9999999999999% the speed of light, your rocket engine is really a time machine. You turn on your rocket and instead of going faster, you make time slow down more and more and more from your perspective. You, personally, could travel across the galaxy in a few weeks if you just had a conventional rocket big enough. On earth thousands of years would pass, but for you, it would be virtually no time at all."], "text_urls": [[]], "score": [3]}}, {"q_id": "77fx9w", "category": "Repost", "title": "The Iran-Contra Affair... What exactly was it?", "title_urls": {"url": []}, "selftext": "I've done a bit of research into it, but for whatever reason I'm having trouble understanding EXACTLY what happened, how the Reagan Administration was involved, how the CIA was involved, and what the consequences of it were. Could someone break it down for me? What happened with Iran, what happened in Nicaragua? Thanks!", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dollkdh"], "text": ["The US was not allowed to trade with Iran (because of the hostage crisis in 1979 when they deposed The Shah, who was... let's say \"friendly\" to the US). Reagan also wanted to support Nicaraguan rebels called The Contras against the socialist government that was there. But he couldn't get the money from Congress to do it. Iran was in the middle of a war with Iraq (whom the US sold weapons to as well), so the US sold them conventional weapons to get money to give to the right-wing Contras. When this was found out, Oliver North was thrown under the bus, and Reagan (dozens of times) did not remember what happened. > What happened with Iran, They got a lot of guns from the US government > what happened in Nicaragua? The Contras weren't very effective. The government in Nicaragua sued the United States in the International Court of Justice but didn't win because they couldn't prove the US directed the Contras, just gave them money and propaganda. However, evidence did come out that the US was condoning atrocities that the Contras were committing."], "text_urls": [[]], "score": [6]}}, {"q_id": "77i5gl", "category": "Repost", "title": "Why do beverages taste different in cans than they do in plastic or glass bottles?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dom1pnt"], "text": ["Probably not what you're looking for, but I know that plastic bottles don't hold carbonation as well because of the way the molecules bond together compared to glass or aluminum cans."], "text_urls": [[]], "score": [3]}}, {"q_id": "77lnt9", "category": "Repost", "title": "How stock trading works/worked? I've only seen it in movies so I'm wondering why these people were always just screaming and waving pieces of paper around and call it a job.", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["domtsp5", "domu0u4", "domtqpt", "domuumv", "domvhyd"], "text": ["The angered mob was buying and selling shares of stock to one another. The setting for these trades is called the trading floor. The loud shouting was to inform anyone your interest of selling or buying a quantity of stock at a price. Once you find someone to make the trade with, you each fill out a trading slip and the transaction is confirmed. Now, more popularly, the asking and bidding on shares is performed via computers.", "It's not like that anymore, but it used to be pretty much what it looks like. Guy 1: \"I'm selling $STOCK for $MONEY\" Guy 2: \"I'll buy 1,000 $STOCK for $MONEY!\" Guy 1: \"Sold!\" Remember, the movie scenes are almost always pegged on some crazy fiscal meltdown. It didn't look that chaotic most of the time. These days it's all digital. Sellers post their prices, and buyers try to buy only to get screwed out of a nickel by unscrupulous flash traders. Heh.", "It's almost all digital nowadays. There are people offering to buy stocks at a certain price and there are people offering to sell stocks at a certain price. A computer matches them and executes the transaction.", "In very very very basic terms it's the super dilution of ownership of a company. Stock is basically, well the stake of a company, broken up into tiny tiny pieces and put on the public market. Usually a board of directors own enough shares to control the company while the shares that go out on the market are called publicly traded shares. Say for example, you are a cannibal recipe website called Facecook and you as a private company have grown in popularity. You now need an injection of money to go to the next level and you don't want some huge investment firm controlling so much they could replace you. You break up your company's ownership into tiny shares, keep a majority for yourself, pass on some smaller amounts to your board of directors and your employees and the rest goes on the market. You set a reasonable valuation for it on the day it goes public, called the IPO or initial public offering. People all want a piece of the action, because they know if you do well, the stock value goes up (including that face cook stock you bought). Stock price goes up as demand goes up, or if there's rumors of something awesome you're doing. But in all honesty, most people on the public market are there as hawkers at a bazaar. Their aim is to buy at low prices and sell at high prices. The amount they get to own of your company is so little, they have little to no say in what your company does as an individual. But as a collective, every time there's Frenzy to buy, they drive your stock price up and inject capital into your company. EDIT (here's the part you were looking for): For individuals who play the game at the frenzied bazaar full time, they're all trying to hit gold. Have those few super massive successful trades that can make them millionaires in a matter of minutes. With thousands of people trading non stop around the world, values fluctuate like crazy. And provided you have the right mix and the right access to buy and sell stocks from the right company, you can make a killing (and lose it). When they scream sell sell sell, they want people to dump the stock because there's reason to believe it will drop. Once it bottoms out. They'll buy it again and sell it once it rises. It's like a manifestation of what nature is - an adrenaline fuelled chaotic race for survival over limited resources where wit, cunning and luck can all work in your favour or you can lose out despite 'doing everything right'", "Nowadays it's almost entirely electronic. Traders submit orders into the exchange that are like \"I want to buy 100 shares of XYZ at $30,\" and as soon as someone is willing to sell at that price, the exchange informs both parties that the trade has occurred. The exchange will also list what the current highest \"bid\" and lowest \"ask\" are, so you'd see that someone is currently willing to buy 100 shares of XYZ for $30 and someone else is willing to sell 500 shares for $30.01. You can also submit a \"market order\" like \"sell 1000 shares to whomever will give me the best price,\" which in the above example might cause you to sell 100 shares to the guy bidding $30, then another 400 to some other guy bidding $29.99, and the last 500 to someone else bidding $29.98. The exchange will automatically figure out who owes what and handle the transactions. However, this was all much harder before computers. Instead of submitting your order automatically, you'd need to have someone on the floor of the exchange yelling about how much you wanted to buy/sell and the price. When you tried to buy stock for your personal account, your bank would then contact their floor trader to buy that stock for you. The pieces of paper were for writing down what trades that trader personally had done. When you'd see those people in movies, it'd be during major moves in the price, which would cause significant activity in the area and increase the general level of chaos. You might think \"why wouldn't they lie about what happened?\" They could do that, but failing to follow through with a trade just because it ended up bad for you would destroy your reputation, and the rest of the traders would know and you'd never get trades again."], "text_urls": [[], [], [], [], []], "score": [53, 51, 41, 9, 4]}}, {"q_id": "77m0ob", "category": "Repost", "title": "How does Silicone hold information. basically giving us computers", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["domwqvo"], "text": ["It is silicon. [Measured by mass, silicon makes up 27.7% of the Earth's crust]( URL_0 ) Silicon is next to aluminum It is a member of group 14 in the periodic table, along with carbon above it and germanium, tin, and lead below. It is a semiconductor, neither a good conductor like aluminum or an insulator. As such it can be loaded with electrons, or have electrons removed leaving 'gaps, or spaces for electrons. This means it can be used as a 'gate' to regulate the flow of electrons, or current. Farmers know gates are very useful. So do electrical engineers, the ability to start and stop a current flow makes transistors, printed circuits, chips, and diodes possible."], "text_urls": [["https://en.wikipedia.org/wiki/Silicon"]], "score": [3]}}, {"q_id": "77mts0", "category": "Repost", "title": "If bones can heal itself, Why cant our teeth do the same?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["don2i1u"], "text": ["Contrary to semi-popular belief, teeth are not bones. As a result, they do not feature the same regenerative abilities as bones."], "text_urls": [[]], "score": [5]}}, {"q_id": "77n1tu", "category": "Repost", "title": "What is it that our bodies do when we sleep? Why do we need it, what is \"replenished\" etc?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["don9sa8"], "text": ["We don't really have a definite answer, some say it's important in the conversion of short term to long term memory, that when you sleep your mind basically gets a chance to\"De-fragment\" all of the information you took in that day. Others say it's necessary in order to give our bodies time to heal and recover, but our bodies are constantly healing and generating new tissue, while sleep may make the process easier it's not as if our bodies only heal while we're asleep. Some scientists believe it's something living organisms simply adapted to do as a way to conserve energy, we can't hunt or gather food when our vision at night is poor, so it would make sense to go dormant as a survival mechanism in order to not waste energy. It could be one of these, it could all of them, or something we don't even know, but at this point the jury is still out. Sleep is necessary to us, but why we and many living organism developed this nessecity is still unknown. *Edit some typos."], "text_urls": [[]], "score": [17]}}, {"q_id": "77qsf0", "category": "Repost", "title": "Is there an 'fps' for sound?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["donzjbl", "donznn2"], "text": ["It's called the sample rate. Standard for CD audio is 44,100 samples per second. Unlike FPS it is usually fixed.", "Yes. CDs use 44 & #8239;100 samples per second. More modern formats are moving to 48 & #8239;000 and some audiophile content uses 96 & #8239;000 or even 192 & #8239;000. Human hearing goes up to about 20 & #8239;000 & #8239;Hz and theory says you need at least double that to represent the waveform (because each cycle involves a wave going up and then down, so you need to capture both peaks). On the lower end of the quality scale, phones use 8 & #8239;000 samples per second, because this is enough to carry the human voice. Unlike video, where you need a whole frame as a \"sample\", sound needs only a single number per channel, i.e., 1 number for mono, 2 for stereo, etc. Each number represents the height of the sound wave at an instant in time."], "text_urls": [[], []], "score": [7, 3]}}, {"q_id": "77rysi", "category": "Repost", "title": "How is binaural audio made and how does it work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dooaq6c", "doobnii"], "text": ["Imagine you held a seashell up to your ear, and you hear it change the sound around you and make it sound like white noise. This is due to it's shape and reflectivity. If you were to put a microphone inside the shell, record the sound, and then play it back on a headphone, you would hear the same effect as if you had a shell up to your ear, because you're using the shell as a kind of audio filter, and recording the result. When it's played back, you hear the filtered sound which your brain interprets as a seashell next to your ear. HRTF or Head Related Transfer Function is an examination of perceptual cues we use in order to tell which direction a sound is coming from. Because of the shape of the exterior ear lobe, and the ear canal, the timbre or quality of a sound changes depending upon the direction it is coming from. This affects not just how loud it is, and which ear it is loudest in, but also if it's clear or muffled, and the delay between when one ear hears it first, and then the other. The brain uses all of these cues in order to understand where a sound is coming from. There have been software technologies that attempt to digitally modify sounds in a stereo headset, in order to provide these directional cues, but binaural audio takes this a step further. Actual ears are used, and a microphone is placed deep inside the ear canal inside of a dummy head, with prosthetic ears. The dummy head adds to the realism by reflecting sounds off of the face and side of the head much like skin, as well as the shape of the artificial ear encoding the directional cues in a very accurate way. When you play back the audio using headphones, your ears are hearing the original sound, modified by the shape of the dummy ear. And since headphones are as direct a way to hear sound as we can get, they act like binoculars for our ears, blocking out external sounds, and giving a very clear audio image, of the recorded binaural audio, and you hear it as 3 dimensional.", "ELI5 answer: it's a way of trying to capture exactly what a person would hear in a particular position, by installing microphones inside a dummy head where your ears would be. If done properly to a high fidelity, and you listen to the results with good headphones, it should recreate the 3D experience as if you were there. Pearl Jam recorded an album - *Binaural* - that use the technique on several slower tracks, including [Nothing As It Seems] ( URL_0 )."], "text_urls": [[], ["https://www.youtube.com/watch?v=Id920P5eg0A"]], "score": [9, 3]}}, {"q_id": "77shpy", "category": "Repost", "title": "What happens on a molecular level when you cut or shred something?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["doobvyv", "dooehoz"], "text": ["You are not breaking apart molecules. You are however breaking the bonds between the molecules", "You sheer the structure. Think of it like tearing apart a lego sculpture. The individual blocks (molecules) are still intact, but you have broken where they lock into other ones."], "text_urls": [[], []], "score": [6, 3]}}, {"q_id": "77tg4e", "category": "Repost", "title": "How do vinyls, specifically their grooves, work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dooi0lb"], "text": ["There is only one long groove on a record. It begins around the outer circumference of the record and spirals in towards the label. As you play a side, you can watch the needle move closer and closer to the center over the 15 minutes-or-so it takes for the side to be played."], "text_urls": [[]], "score": [3]}}, {"q_id": "7837j0", "category": "Repost", "title": "How important is the language in humans' thinking process? How were humans able to think before the existence of any language?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["doqnylv"], "text": ["Language is definitely not required for the human thinking process, though the task of explaining your thoughts using a language can help. Computer programmers often use a technique called \"rubber ducking\", where one programmer explains his or her problem to another programmer, while the second programmer does nothing except nod their head and say \"uh huh\" over and over again. This process of forcing thought to language helps organise the thought process, and helps with problem solving."], "text_urls": [[]], "score": [4]}}, {"q_id": "786cy8", "category": "Repost", "title": "why is it that when all other species show their teeth it is an act of aggression but when humans do it, it's a friendly gesture?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dorfqdo", "dorg0ol"], "text": ["The smile evolved in primates approximately 30 million years ago, humans got it from there. Evolutionary biologist think it evolved from a submission response. IE it used to be a I submit to you, co-opted to an I approve/am happy. What does this have to do with teeth? The submission response was in turn an adaptation of a fear response. I am scared of you, so I submit to you. Many fear responses involve the bearing of weapons or making yourself seem bigger, see cat's arching backs or hissing. TL:DR: used to be fear look - > submission look - > approval look.", "Here is a good [Scientific American article on that very subject]( URL_0 ). It's interesting to note that amongst babies showing teeth is more a sign of fright than it is of friendliness/friendship. That provides a clue and is accordance with the saying \"ontogeny recapitulates phylogeny\" (i.e. the development of an organism tells you about its evolutionary history). Frank McAndrew, a facial expression researcher has this to say: > \"Baring one's teeth is not always a threat. In primates, showing the teeth, especially teeth held together, is almost always a sign of submission. The human smile probably has evolved from that. > \"In the primate threat, the lips are curled back and the teeth are apart--you are ready to bite. But if the teeth are pressed together and the lips are relaxed, then clearly you are not prepared to do any damage. These displays are combined with other facial features, such as what you do with your eyes, to express a whole range of feelings. In a lot of human smiling, it is something you do in public, but it does not reflect true 'friendly' feelings--think of politicians smiling for photographers. He also points out that it is so deeply ingrained in us that even congenitally blind people smile in the same way in response to the same stimulus as sighted people. There are a few links to further reading on the subject at the conclusion of the article."], "text_urls": [[], ["https://www.scientificamerican.com/article/how-did-the-smile-become-a-friendly-gesture-in-humans/"]], "score": [9, 3]}}, {"q_id": "788r0x", "category": "Repost", "title": "Why do India and China have such massive populations in comparison to the rest of the world?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dorvsn7"], "text": ["I'm almost certain this has been answered before, but it's largely due to geography. India and China both have exceptionally fertile river valleys capable of supporting large populations with pre-industrial technology. Even before the world population started exploding during the past two centuries, they were the two largest and richest civilizations on Earth - for example, in the early days of India being a part of the British Empire, it's 'GDP' was over half the productivity of the entire British Empire (including the British Isles themselves)."], "text_urls": [[]], "score": [6]}}, {"q_id": "78ey8c", "category": "Repost", "title": "What do the police do with the money after a big drug bust?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dot9q0w", "dotauhd"], "text": ["In the USA, the money is essentially charged with suspected illegal activity and seized to be used as law enforcement sees fit, unless the owner of the money can prove that the money was not used in any illegal activity. This process is called [civil forfeiture]( URL_0 ). Note that this process is separate from the owner being charged.", "And is there a quota for bust money budget? Like do they increase #of speed ticket quota if there is a shortage of bust money this quarter? Edit. Now I want to see the police financial statements. Are these public?"], "text_urls": [["https://en.wikipedia.org/wiki/Civil_forfeiture_in_the_United_States"], []], "score": [35, 3]}}, {"q_id": "78j9pj", "category": "Repost", "title": "Why does the name \"Germany\" in English sound so much different than the actual name of Deutschland?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dou94z6"], "text": ["\"Germany\" as a place name (from the Latin Germania, named for the \"Germani\" people) existed long, long before \"Deutchland\". That part of Europe has gone through a lot of political changes throughout history. It's almost more appropriate to think of \"Deutschland\" as the nation currently in the area called \"Germany\". 200+ years ago \"Germany\" was the home to the Holy Roman Empire. We still called it the region \"Germany\"."], "text_urls": [[]], "score": [8]}}, {"q_id": "78olk6", "category": "Repost", "title": "What's an ion thruster? How does it work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dovened", "dovncfa"], "text": ["It is a propulsion device that uses a combination of a gas plus some sort of electric field to accelerate the gas and shoot it out the back of the thruster assembly. The gas, usually xenon or argon, is given a negative charge. electric charge by passing it over an electric filament. The gas is then sent to the thrust chamber where they are accelerated by a combination of magnets and electrically charged plates. That acceleration combined with the ejection of the ions out the back gives the assembly its thrust.", "In space travel there's a problem often referred to as \"the tyranny of the rocket equation.\" You have to use fuel to accelerate, but the more fuel you bring the more fuel it takes to accelerate. To go incrementally faster you need exponentially more fuel. To maximize the \"fuel efficiency\" of a space propulsion system you want the highest possible exhaust velocity. This means that you get more impulse (force \u00d7 time) for a given amount of fuel. Rockets are often described in terms of \"Specific impulse,\" or Isp, which quantifies this value. It's in units of \"seconds.\" In a chemical rocket the energy for accelerating the propellant comes from the propellant itself. This means that there's a limit on how fast the exhaust can ever be: even if you convert 100% of the chemical energy of the fuel into thermal energy of the exhaust and perfectly handle the nozzle there's a max exhaust velocity you'll achieve. In an ion thruster you do away with the idea that the propellant should be an energy source, too. You harvest energy from a solar panel (or other source, but only solar panels are attractive for their weight), then you use strong electric fields to massively accelerate tiny quantities of fuel to speeds that can start to be non-trivial fractions of the speed of light. These thrusters typically have tiny amounts of thrust, but they use fuel incredibly slowly. The general concept for using an ion thruster is that it will provide thrust over weeks or months, ultimately reaching speeds that are unfeasible for a chemical rocket. While chemical rockets are often doing well to have Isp ratings in the 400-500s range, ion thrusters can sometimes reach the 10,000s+ range."], "text_urls": [[], []], "score": [10, 7]}}, {"q_id": "78pog1", "category": "Repost", "title": "In the search for extraterrestrial life, why do we assume water must exist on a planet for life to exist? Why can't there be organisms with different biologies that survive on elements other than hydrogen and oxygen?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dovnpad", "dovo13o"], "text": ["Because our only point of reference is carbon-based lifeforms that rely on water. Of course there's the potential for other forms of life that are not carbon based and/or don't live in enviornments with water, but how would you even begin to look for something you can't define since you have no point of reference? The universe is mind-bogglingly large, you need to narrow down your search somehow.", "because we don't have any knowledge of those types of life. we would have no idea how they work or how to look for them. we are very familiar with carbon based life, so that's what we're looking for. sci fi shows have made up silicon based life forms but they're just made up. we have no idea if they would exist or not."], "text_urls": [[], []], "score": [4, 3]}}, {"q_id": "78pprh", "category": "Repost", "title": "How do TV programmes like The Simpsons make money from being aired?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dovnvip"], "text": ["Fox pays the creators of The Simpsons to create 1 or more seasons (depending on the contract). They use this money to pay the writers, animators, voice actors, creative staff, and everyone else involved with making the actual show. Fox is paying the creators because a certain number of viewers will watch the show which means that companies are paying Fox to air commercials during the time slot The Simpsons is airing. The more viewers, the more ad revenue can be asked for. Depending on the contract, Fox might also get a cut of any DVD/digital, merchandise sales."], "text_urls": [[]], "score": [4]}}, {"q_id": "78qgud", "category": "Repost", "title": "How does hand soap kill/destroy/remove bacteria on your hands?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dovv0e7"], "text": ["A lot of it is simply mechanical removal. Soap molecules have one end that is attracted to water and one end that is attracted to oil. If bacteria get coated in these molecules, then water will rinse them off more easily (with a good scubbing). Soap can also kill bacteria directly, because their membranes are also made of molecules with one water-loving end and one oil-loving end. This allows soap molecules to interact with these membranes, and this interaction can punch holes in the bacterial surface."], "text_urls": [[]], "score": [5]}}, {"q_id": "78u9u2", "category": "Repost", "title": "Difference between lobbying and bribing?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dowqk4f", "dowqdfr", "dowrelt"], "text": ["There are a few main differences: * The first is transparency. Lobbying is recorded, and generally has to be accounted for. A bribe would obviously be unrecorded and under the table. By keeping track of donations via lobbyists, it makes it harder to make really oblique payments. Most political officials are also restricted from receiving certain kinds of gifts or services. * The second is the level on which it takes place. Bribery is generally done on a one-to-one level. A single person offers money to a single official for a specifically desired outcome. Lobbying is a bit more general, a donation to a larger campaign effort or party coalition, and usually with a more broad goal of leaning things a certain way, but not directly paying for a specific returned outcome. * Additionally, unlike how a bribe is generally considered, there's no true obligation on the part of a government official to act a certain way. There's no recourse or threat that can be done by a lobbying group if the official decides to not vote along the lines they wanted, regardless of donation. They can simply choose not to donate to that person again. * Laws also put a (theoretical) limit on how much can be donated from one person or group at one time, and all that money is tracked and logged by oversight committees.", "Not much I'm afraid. Their pretty much the same thing with bribery being illegal but lobbying legal. Also, lobbying usually includes a bunch of parties but bribing only 2", "There is a huge misconception that lobbying is just bribery. In reality lobbying is much broader. If you ring up your representative, you are lobbying. If you present a report to a representative, you are lobbying. Basically any contact with MP's/Senators (or your local equivalent) for political purposes constitutes lobbying. The democratic process *relies* on lobbying."], "text_urls": [[], [], []], "score": [8, 5, 3]}}, {"q_id": "78x7fp", "category": "Repost", "title": "Why is it after an activity like running, things like music sound like they are going in slow motion?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["doxd4ww"], "text": ["Never experienced that. Perhaps you should see a doctor?"], "text_urls": [[]], "score": [6]}}, {"q_id": "78zijj", "category": "Repost", "title": "the first law of thermodynamics", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["doxwt0d", "doxwvuh"], "text": ["In an isolated system, energy can be changed to other forms but it cannot be created or destroyed. This law is true for all isolated systems and non-nuclear reactions.", "The 1st Law of Thermodynamics states that in thermodynamic systems energy must be conserved. You can move energy around, you can change the form of the energy, but you can't create or destroy energy. Put in simple terms \"There's no such thing as a free lunch.\" Everything costs something."], "text_urls": [[], []], "score": [11, 3]}}, {"q_id": "790438", "category": "Repost", "title": "What purpose do eggs serve in baking? It seems as if we put eggs in almost everything we bake, but what do eggs do chemically that is crucial for the baking process?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["doy2rue"], "text": ["As you probably already know, oil and water don't mix. Well, this can be a problem when you're cooking, because you might have some ingredients that are water-based, and other ingredients that are fat (or oil) based. So, how do we mix them? We need an intermediary - something that can combine the two of them. Egg yolk contains lecithin which is great for this purpose - it's a molecule that attracts water molecules on one side and oil molecules on the other. Without this, lots of foods would separate, and you don't want that!"], "text_urls": [[]], "score": [8]}}, {"q_id": "7920lf", "category": "Repost", "title": "Why does the urge to pee increase so much when you are approaching the front door?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["doyi3qf"], "text": ["Pavlov call. Your body predicts as task and prepares for it. Same with ordering food. You will create lots of saliva while ordering food because your body knows it is going to take food so more saliva will help break down the food."], "text_urls": [[]], "score": [12]}}, {"q_id": "793t1b", "category": "Repost", "title": "How are cheat codes discovered in video games?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["doyvyi7"], "text": ["The vast majority of them are released by the developers themselves. A lot of the early cheat codes were simply stated in strategy guides or gaming magazines, so intentionally distributed for people. Another group of them come from developers but not officially, they just leak over time since many coders, devs and testers were aware of them eventually they share that information. Sometimes the 'cheat codes' are part of a debugging system that just never gets removed when the game ships. Then another portion are discovered in the code itself. Eventually someone will crack open the game code, look around and find extra areas or extra codes and commands that will do various things. And some of it is password systems like in Old NES games where people kind of crack the code and figure out entering certain codes will force the game into a specific state, Metroid in particular has a big list of these where the save game can give you unlimited missles, invincibility etc... But very few of these things are discovered by just hitting random buttons to find them."], "text_urls": [[]], "score": [4]}}, {"q_id": "7943xx", "category": "Repost", "title": "How does a mirage work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["doyz0xs"], "text": ["The example that's easiest to explain in simple terms are mirages in the desert, often mistaken for bodies of water. Mirages can occur elsewhere (e.g., long stretches of highway or at sea), but let's stick with just one place for simplicity's sake. One thing to keep in mind: mirages almost invariably occur in conditions involving bright, unclouded sunshine and relatively high temperatures. In terms of their *effect*, mirages are basically air-mirrors. Unlike regular mirrors, mirages function by \"refraction\" (i.e., *bending*) light rather than \"reflection\" (i.e., *bouncing* light), but the optical *effect* winds up being pretty similar in this case. What happens is that in the desert, the temperature in the few inches above the sand is *dramatically* hotter than the temperature even one foot up. As much as 30-40F. Light behaves differently in different media, yes? This is why lenses work: the transition from air to glass *bends* the light. Well, the *temperature* difference in the few inches of air immediately above the surface of the sand is enough to act like a lens, of sorts. Light comes down from the sky, is bent by that thin layer of hot air so that it comes *up* to meet your eye, *without* reflecting off the sand. So you're looking *down*, but the light you're seeing actually comes from *above*, and has not interacted with the surface of the sand at all. Because the eye expects bodies of water to reflect the sky above them, your brain interprets this *refraction*, caused by a thin layer of hot air, as if it were the result of *reflection* from a body of water. Mirages can create other sorts of images too. For example, you can see an inverted image of a ship near the horizon, or a mountain off in the distance, not just an apparent \"reflection\" of the sky. Same principle."], "text_urls": [[]], "score": [3]}}, {"q_id": "7944t3", "category": "Repost", "title": "Before toothbrushes, how did humans clean their teeth?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["doz4311", "doyydzv", "doyyllf"], "text": ["I think there is also a difference in diet that makes cleaning a little less important. We eat a lot of sugar that was not available historically.", "Some didn't, some picked at their teeth with twigs and stuff, some would fray the end of a fibrous plant stalk and make a little brush, etc.", "Basically by gnawing on twigs and roots and stuff. Muslims still have this tradition and will sometimes use a sewak. According to some of their legends they can earn favor with their gods by using a sawak before praying URL_0"], "text_urls": [[], [], ["https://www.amazon.com/Sewak-Al-Falah-Traditional-Natural-Toothbrush/dp/B00F22IZY4"]], "score": [15, 11, 6]}}, {"q_id": "797s3z", "category": "Repost", "title": "How did last names come to existence? How are new last names made?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["doztuad"], "text": ["Many were their professions. Smith, Baker, or my father who made our family name after his favorite duty. Dickinson"], "text_urls": [[]], "score": [4]}}, {"q_id": "799f3a", "category": "Repost", "title": "Why if something spins very fast we see that it changes direction.", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dp06683"], "text": ["That's actually an artefact of the *recording* process. Since we only capture a certain number of frames each second, if there's, for example, a clock face with the minute hand spinning around extremely fast, then if it's moving at *just under* once around every second, and we're recording at 60 frames per second, then every time the camera records the scene, the minute hand will be slightly *before* where it was the previous frame, since after the picture it spins all the way around again until just before its current position which is right when the camera is ready to take another picture. Imagine taking one photograph every second. If you are walking around in a circle, but are walking that circle in just under one second, then every time the photo is taken it'll be just before you reach the point you were in when the photo was last taken. If you put all of these photographs together one after the other, you'll *appear* to be moving backwards, because the parts where you walked all the way around are missing, and so when we watch an animation of those photographs, we assume you were just walking backwards and taking the photos more rapidly."], "text_urls": [[]], "score": [8]}}, {"q_id": "79azcl", "category": "Repost", "title": "How are we able to drink liquid upside down?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dp0i5ld"], "text": ["Same reason astronauts can eat in space: Humans don't rely on gravity to consume things. We swallow with muscles."], "text_urls": [[]], "score": [3]}}, {"q_id": "79fp90", "category": "Repost", "title": "Why melting icebergs cause sea level to rise while ice cubes melting in water glass don't?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dp1kz6m"], "text": ["I may be wrong but I always thought these icebergs were, at least partially, out of water, on land. So the run off from the melting glacier/Berg goes into the water."], "text_urls": [[]], "score": [3]}}, {"q_id": "79hmkp", "category": "Repost", "title": "How do activated carbon filters work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dp204ov", "dp22br8", "dp2c7ko", "dp2ek8a"], "text": ["Basically the carbon has tiny tiny pores that pull things out of water/air/etc via what's called the van der waals force. Different base materials (coconut, wood, animal bone) result in different size pores which are used in different applications depending on the medium and what you're trying to filter out.", "The carbon used is created by heating some kind of organic material in an oxygen-free, low-pressure chamber. Apparently coconut husks wok well for this. The result of this is pyrolytic carbon. On a very small scale, the carbon consists of a spongy, randomized, lace-like network of carbon atoms. The material has an extremely high surface area. Large molecules such as volatile organic compounds (VOC's) tend to get trapped in all the tiny voids and crevices in the material, while small molecules like N2, O2, or H2O can fairly easily pass through it.", "Insanely huge surface area, allowing it adsorb huge amounts (relative to the amount of carbon) of what have you", "They are two reasons: - Very high ratio surface/volume -Due to incomplete burning process there are several different organic groups attached that can hold back different kinds of molecules, this with the non-specific forces allow activated carbon to filter a very large range of compounds."], "text_urls": [[], [], [], []], "score": [40, 10, 8, 3]}}, {"q_id": "79jokn", "category": "Repost", "title": "Why do ice cubes crackle when liquid is poured on them?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dp2hlj7"], "text": ["So most things expand when heated and retract when cooled. Because ice is already so cold, when you pour a liquid on ice, the surface that the liquid hits will instantly expand, and the rest of the ice doesn't have time to catch up. The top surface expands from heat and the rest of the ice remains cold and doesn't expand. Suddenly, boom, the ice cracks. Tl;dr: Thermal shock."], "text_urls": [[]], "score": [12]}}, {"q_id": "79mv8w", "category": "Repost", "title": "The Boltzmann brain theory", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dp37yq1"], "text": ["The 2nd Law of Thermodynamics (which for our purposes says that the disorder in an isolated system can't go down over time) is statistical, not absolute. Over extremely large spans of time, the possibility of a fluctuation from a disordered to a more ordered state in any particular region approaches 100%. An eternal universe spends infinitely more time in it's highly disordered later stages than it's more ordered early stages. Thus, what is more likely: that you are really living on Earth with several billion other humans, 14 billion years from the birth of our observable universe, or that you are a statistical fluctuation of a brain that just came into existence at some arbitrary point in time, structured in such a way that you have memories corresponding to living on Earth with several billion other humans, 14 billion years from the birth of our observable universe?"], "text_urls": [[]], "score": [4]}}, {"q_id": "79uiee", "category": "Repost", "title": "Zoning out while driving and not killing anyone", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dp4zb32", "dp573jn", "dp4yjfd"], "text": ["You go into autopilot, your brain doesn't take logs unless something interesting occurs, but while you're in autopilot you are still actively scanning the road and controlling the car and responding to routine inputs(stop signs, road markings, corners in the road) Once you do a task enough your brain makes an autopilot routine for it, this is why you can walk and chew gum at the same time. Why you can have a deep conversation with someone and walk up a flight of stairs. Walking has been fully automated since you were young, if you think about how you're walking up the stairs it'll be awkward. While you may not remember paying attention it doesn't mean that your brain wasn't paying attention. It just means that this morning's commute was completely uneventful", "While you are doing something boring and repetitive like driving, you are fully aware and paying attention in the moment. All that happens within the context of your short-term memory. Why you feel like you zoned out is because nothing interesting enough happened to transfer those memories from short-term to long-term memory. You are aware, you just don't remember being aware.", "To be completely honest, that's probably about half luck and half subconscious. A term they love to use in driver's ed is \"highway hypnosis\" which is basically just what you described, what you're doing is so mundane and consistent that it's practically as automated as breathing, to the point where you end up speeding (or in some cases slowing down, whichever direction your foot decides to go, but generally gravity is the winner there), potentially swerving/drifting until you hit rumble strips, etc and so forth. There are an ton of accidents that result from this situation, but that also has to factor in density of traffic, other people making sketchy choices as they change lanes or merge and the like."], "text_urls": [[], [], []], "score": [28, 4, 4]}}, {"q_id": "79vdvk", "category": "Repost", "title": "how can a GPS or in car navigation system work with no internet, but google maps on my phone requires a signal?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dp50qrh", "dp50omp"], "text": ["You don't need a connection to the internet for the GPS, you need it for the maps. GPS just receives a signal from the GPS satellites and uses it determine your location. The maps however needs to be downloaded from somewhere - in your car navigation system the maps are already stored on the device, but in Google maps they are downloaded on the fly.", "Your phone doesn't save the actual maps of places locally and, by default, downloads them from Google's servers when you use google maps whereas your car's computer just stores them. You can download and store maps on your phone to use google maps offline if you know you'll be without internet. Edit: you need the maps to do anything other than finding your latitude and longitude (i.e. reverse geocoding to turn those coordinates to an address). The GPS itself doesn't require an internet connection, it's all the other data you need to use the maps service that does."], "text_urls": [[], []], "score": [3, 3]}}, {"q_id": "7a38wl", "category": "Repost", "title": "How are video games cracked?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dp6rswn"], "text": ["Video Games are ran by a set of internal codes. If someone has the appropriate software they are able to see the internal codes (which are hundreds of thousands of pages long). If they are able to get into which line of code contains the players ammunition (for instance) then they are able to modify that line of code to constantly be changed to full ammunition. Cracking is not easy, depends on the publisher really."], "text_urls": [[]], "score": [3]}}, {"q_id": "7a6hpg", "category": "Repost", "title": "If most trees shed their leaves at winter, does that mean there is less oxygen in the winter months due to photosynthesis?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dp7im9v"], "text": ["Yes, there is seasonal variation in atmospheric oxygen concentrations, but it's important to note that trees are not the primary source of atmospheric oxygen. Most of the oxygen in the atmosphere comes from phytoplankton in the ocean."], "text_urls": [[]], "score": [5]}}, {"q_id": "7a72tt", "category": "Repost", "title": "What is subnetting?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dp7pnkb"], "text": ["It's a way to divide up the IP addresses of the Internet so everyone can find them (4+ billion of them on the IPv4 Internet). Every computer, phone, etc, can't keep track of billions of addresses and how to reach them, so grouping them into subnets is necessary. It's like phone numbers - +1 (555) 555-5555. The +1 means the U.S. The (555) is an area code (or NPA) inside the U.S. The 555- is an area within that area code (NXX). And then the 5555 is one of 10,000 possible phones in that area. If I make a call to my local NXX, the local switch knows where all those numbers are. If it's not in my local NXX, but it's in the same area code, it can send it to a nearby switch that would know where those 10,000 numbers are. If I call out of my area code, the local switch doesn't need to know all about the number, but will know from the country code or area code that it should send it to a long distance provider / switch. Dividing up the address space is necessary so everyone doesn't need to keep and update a list of billions or trillions of numbers and where to find them. You keep track of your local numbers and make sure everyone else knows that you've got that block of numbers so they can reach you."], "text_urls": [[]], "score": [3]}}, {"q_id": "7a8xgy", "category": "Repost", "title": "why do things get darker when wet?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dp84to5", "dp82t6l"], "text": ["When things are wet they have a layer of water over them. Light hits the surface, and some of it gets absorbed, then light hits the object and bounces back, but some of it is absorbed again. As the light goes back through the water layer, some is absorbed, some goes through and some more goes back towards the object. So when things are wet less light can reflect off of it and into your eyes.", "Imagine light is food. When you add water to things it eats up some of that light. So when you look at it it is darker."], "text_urls": [[], []], "score": [7, 6]}}, {"q_id": "7aa6ch", "category": "Repost", "title": "Why does wind or moving air in general feel cooler than the surrounding air?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dp8bypd"], "text": ["Humans produce heat so any wind that passes us removes some of our own radiated heat. Like blowing on hot food. Even though the wind may be hotter it will still feel cooler when it blows by because instead of our heat adding to the heat from the air at least now our radiated heat is being pulled away."], "text_urls": [[]], "score": [3]}}, {"q_id": "7abpar", "category": "Repost", "title": "What physically is a smell?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dp8mkay"], "text": ["Odors comes from molecules that have evaporated into the air, the same way water becomes water vapor. Your nose has thousands of receptors, each tune to a particular kind of molecule. When a molecule binds to them, it sends a signal to our brains we interpret as a particular smell."], "text_urls": [[]], "score": [6]}}, {"q_id": "7af7zp", "category": "Repost", "title": "Why are there no green flowers?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dp9giie"], "text": ["The point of flowers is to attract pollinating animals like insects and birds. It's essentially a lure to get such animals to approach the flower (and the right part of the flower) to collect and distribute pollen. That said, [there are green flowers]( URL_0 )"], "text_urls": [["https://www.proflowers.com/blog/green-flowers"]], "score": [3]}}, {"q_id": "7aidb1", "category": "Repost", "title": "How does hypnotism work? Are all people susceptible?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dpa5m97"], "text": ["In psychology, we've figured out that hypnotism isn't really a thing. Any effect attributed to hypnotism is almost entirely due to to the \"hypnotized\" person being willing to trick themselves into believing it is working, so they just go along with whatever the hypnotist is suggesting. It's a placebo effect."], "text_urls": [[]], "score": [6]}}, {"q_id": "7aits9", "category": "Repost", "title": "What\u2019s the science behind \u201cBest used By\u201d dates on food?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dpadghd"], "text": ["Varies depending on the food, but basically we store it as intended and watch it/taste it. Mostly you only have to do this for parts. So while a cake will last a long time, cream won't so we don't test a cream cake since we know it will be off when the cream will be off, and the dates for typical cakes and creams are widely known. In some cases there is no method and it is simply a case of \"We are legally required to put a date on this food, so here is a date.\" Tinned food for example will last indefinitely without spoiling yet has a date printed on it for legal reasons. Other times it is an extrapolation. Bottled water for example *does* expire because the plastic leeches into the water. We can take a few samples and then extrapolate that the water will no longer be fit for consumption by a certain date."], "text_urls": [[]], "score": [3]}}, {"q_id": "7aiw1u", "category": "Repost", "title": "Why does the the thermostat need someone to direct it to either heat or cool the room? Why isn't just providing the desired temperature enough for the system to figure it out itself?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dpa924z", "dpa9xs0", "dpa927i", "dpabiph", "dpacxvo"], "text": ["Because that\u2019s not usually a desirable feature. For example, I have my thermostat set to 65 and heat because it\u2019s starting to get cold. If the temperature gets a little higher than that, I\u2019m not going to complain, I just don\u2019t want it to go lower. The opposite is true in the summer. I\u2019ll set my thermostat to 78 and cool. If the temperature drifts down to say, 75, why would I waste energy bringing it back up to 78 when I\u2019m trying to stay cool?", "Most new thermostats have auto feature where you set range and it does just that. Personally, I don't use it because I feel like both turning on in the same day might break something. I have no evidence of that, just crazy.", "If the room is set to cool at 72, but the thermostat reads the air as 68, the system won't kick on, because it knows it is cold. I am not an HVAC tech, so I don't feel qualified to answer the other piece, but maybe because it would be incredibly inefficient to keep switching back and forth around a temperature, and stressing on the components.", "My Google Nest does. Most thermostats you install yourself will take a range and keep it inside that range. You're probably confused by older thermostats and/or new building thermostats. With new building thermostats it's fairly simple - the builders were cheap and a fancy thermostat costs more.", "Newer thermostats commonly come with heat, cool, and auto settings for the mode of operation. The auto setting usually incorporates a programmable deadband that is factory set to 5 degrees. when changing the heating setpoint in this mode from 67 to 68, you\u2019ll notice the cooling setpoint raise from 72 to 73. This allows the HVAC system to run without \u201cfighting\u201d itself. It works well, but i\u2019ve seen most customers prefer the swap modes manually."], "text_urls": [[], [], [], [], []], "score": [16, 9, 5, 4, 3]}}, {"q_id": "7ankug", "category": "Repost", "title": "Why is the moon so much smaller on my phone's camera than what it looks like with my eyes?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dpbe1zp", "dpbe5wz", "dpbepwp"], "text": ["Your phone's camera uses what's called a wide angle lens. Because of the wide angle lens, it looks at a wide area all at once. This is good for taking group photos and pictures of things nearby, but when you take a picture of something small or far away like the moon then your phone's camera is looking at not only the moon but a lot of space around it. Your eyes are different. You see a smaller amount at once and your brain makes this even more apparent because you're able to focus on little details of things thanks to your \"fovea\". The fovea is a little patch in the back of your eye which makes your eyesight its absolute best right in the middle of what you're looking at.", "Your phone camera has a wide angle lens. This allows you to fit more stuff into a single shot, but the side effect is that everything in the distance becomes smaller to fit into the frame. The same thing happens with the moon. Since it is far away, it becomes smaller on a cell phone camera picture. The opposite is also true: if you take a picture of the moon using a telephoto lens, the moon can appear absolutely massive relative to the foreground.", "Some of this is in your mind. Your impression of an object's size is subconsciously adjusted on the basis of many cues. For example, people automatically have an impression of an object's actual size independent of how far away it is. It's well known that the moon seems to us to be bigger when near the horizon that when it's high in the sky. Some the effect is because human eyes have better dynamic range than cameras, or at least than JPEG files. If you point your camera towards the dark sky it will automatically try to adjust to brighten the image. Probably all the pixels of the moon will be at maximum brightness, allowing no way to see any features. Even though the moon is quite a dark grey object, it's also a sunlit object so daytime exposure settings are more appropriate than night-time ones. Without a very long lens it will take up such a small percentage of the image that any automatic exposure system will largely ignore it. Phone cameras typically don't have manual settings."], "text_urls": [[], [], []], "score": [23, 8, 3]}}, {"q_id": "7aqits", "category": "Repost", "title": "How does anti-dandruff shampoo like Head & Shoulders for example work? Does it really help to decrease amount of dandruff and HOW?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dpc009o"], "text": ["Mostly, it contains a fungicide which kills the microscopic fungus (similar to a yeast) that causes much dandruff. It also sometimes contains a moisturizer which can help if dry scalp is adding to your dandruff."], "text_urls": [[]], "score": [6]}}, {"q_id": "7axiu4", "category": "Repost", "title": "How does a Jet Afterburner work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dpdjmwp", "dpdjp2f"], "text": ["Raw fuel is dumped in to the exhaust pipe and is ignited to create the thrust. If you are interested in jet engines and How they work, here is a cool YouTube channel about jets, their working and maintenance of them URL_0", "It's actually neither of those. Afterburners simply inject fuel downstream of the turbine, where it burns, increasing the velocity of the exhaust, hence increasing the speed of the plane. This comes at the cost of being incredibly fuel inefficient."], "text_urls": [["www.youtube.com/user/AgentJayZ"], []], "score": [5, 3]}}, {"q_id": "7aznxb", "category": "Repost", "title": "CPU cores, logical cores, threads, and hyperthreading, and how they all work together?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dpe3q5u", "dpea5dm"], "text": ["Yer not alone in askin', and kind strangers have explained: 1. [ELI5:CPU Hyper-threading and Threads ]( URL_7 ) 1. [ELI5: Hyperthreading ]( URL_4 ) 1. [ELI5: How Hyperthreading works/what Hyperthreading is ]( URL_0 ) 1. [[ELI5] Why does Intel Hyper-threading use only 2 threads per core(1 physical core as 2 logical cores), why not more? ]( URL_6 ) 1. [ELI5: What exactly is the difference between \"cores\" and \"threads\" on a CPU? ]( URL_3 ) 1. [ELI5: What is hyper-threading? ]( URL_1 ) 1. [ELI5 Someone explain CPU cores to me ]( URL_2 ) 1. [ELI5: How hyper-threading works and why we can't have a core hyper-threaded more times. ]( URL_8 ) 1. [ELI5: How does hyperthreading in Intel CPUs work? ]( URL_5 )", "A **CPU core** is a processing unit. In a multicore chip, each of them functions as a regular single core processor, but they usually share cache memory. Therefore they are bound to some synchronization issues, and a 4 core processor doesn't guarantee a 4x increase in performance over a single core processor. A **thread** is a sequence of instructions executed on a core. Usually this is one process at a time, but a thread may switch between processes rather quickly. Since not all instructions require the full hardware of a core, smart scheduling can use these unused resources for instructions of a second thread. With small hardware adjustments as well, one physical core can simulate multiple **logical cores** which each handle a thread. This is called multithreading, and usually done for two logical cores per single core. Intel calls its implementation of this **hyperthreading**, AMD calls it **Simultaneous Multithreading** (or SMT)."], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/mq98c/eli5_how_hyperthreading_workswhat_hyperthreading/", "https://www.reddit.com/r/explainlikeimfive/comments/2xqf8s/eli5_what_is_hyperthreading/", "https://www.reddit.com/r/explainlikeimfive/comments/4pjtim/eli5_someone_explain_cpu_cores_to_me/", "https://www.reddit.com/r/explainlikeimfive/comments/5xcjnc/eli5_what_exactly_is_the_difference_between_cores/", "https://www.reddit.com/r/explainlikeimfive/comments/33cx7e/eli5_hyperthreading/", "https://www.reddit.com/r/explainlikeimfive/comments/1ywzbk/eli5_how_does_hyperthreading_in_intel_cpus_work/", "https://www.reddit.com/r/explainlikeimfive/comments/51ivxt/eli5_why_does_intel_hyperthreading_use_only_2/", "https://www.reddit.com/r/explainlikeimfive/comments/1y8q7m/eli5cpu_hyperthreading_and_threads/", "https://www.reddit.com/r/explainlikeimfive/comments/43hk9x/eli5_how_hyperthreading_works_and_why_we_cant/"], []], "score": [7, 3]}}, {"q_id": "7b0d2w", "category": "Repost", "title": "How does a lie detector work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dpe8m9y", "dpe8rt8"], "text": ["It doesn't. There is absolutely no proof that any purported \"lie detector\" test (polygraph, VSA, etc) actually works. The inventor of the polygraph actually said many times that it doesn't work. Polygraphs claim to detect falsehoods by measuring heart rate, respiration, blood pressure, and galvanic skin response. They may accurately measure those things, but none of those factors are related to lying in any meaningful way.", "Well, first lets get this out of the way: it doesn't measure lies. What a lie detector measures are physical stress responses. It measures very small physical responses like heartbeat, blood pressure, muscle contractions etc. The idea is that if someone lies, they are going to be more stressed out about that then when they are telling the truth and the test will show that. In reality, these tests are bunk. People can have stress responses for any number of reasons (like, say, discussing an incredibly traumatic thing) and similarly, plenty of people can lie without having any bodily response whatsoever (plenty of murderers that passed polygraph tests)"], "text_urls": [[], []], "score": [27, 8]}}, {"q_id": "7b2417", "category": "Repost", "title": "How do aircrafts know when they are being targeted?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dpennhj", "dpepsg3"], "text": ["Two basic ways: Sensors on the aircraft detect the targeting radar of a ground installation or missile being pointed at the aircraft. Radars depend on hitting a target with energy and then detecting the energy as it bounces off the target and returns. Planes can detect when a radar is simply scanning the whole sky and when it is focused specifically on them by analyzing the radar energy hitting the plane. Missile Approach Warning systems scan the sky for missiles using pulse-doppler radar, infrared, and ultraviolet sensors. The radar can quickly detect objects moving fast towards the aircraft, and the IR/UV sensors look for the bright light produced by the missile's rocket motor.", "Most commonly used missiles and platforms capable of firing missiles use radar to detect and range their target. Military aircraft are equipped with radar warning receivers. Signals from antennas placed on the aircraft pick up radar pulses then send them pulses through the radar warning receiver where they are processed. Each type of radar platform has a unique signature based on things such as frequency and pulse width. The radar warning receiver is pre-programmed to identify these radar signatures and alerts the pilot if a detected signal matches a known threat. If the threat is the radar from a missile, it will make a \"beep beep beep beeeeep,\" prompting the pilot to take evasive action and/or launch countermeasures. Source: Engineer that makes radar warning receivers."], "text_urls": [[], []], "score": [30, 6]}}, {"q_id": "7b3e4k", "category": "Repost", "title": "Why is cancer so hard to cure?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dpey2jr", "dpey7ly", "dpey9oy"], "text": ["A \"cure for cancer\" will NEVER exist. Cancers are a huge number of widely varied diseases, the only common link is out of control cell reproduction. There are so many types and subtypes it's insane", "It is so hard to cure because it's not caused by a germ or a bug. It is parts of your own body that decides to grow in a way your body doesn't want it to. And to get rid of cancer, doctors have to figure out a way to kill your bad cells without also killing your behaving cells.", "We can't. There is no cure for cancer. That sucks to say, but it is true. There are so many different types of cancer that finding a cure for cancer is impossible. Cancer manifests itself in so many different ways, that have so many different behaviors, that curing it is functionally impossible. Cancer also has the nasty fact of being normal cells that have gone rogue. So killing the tumor without killing the surrounding healthy cells is difficult. Many, many different things kill cancer cells. Far fewer do that without colossal risk to patient. I'm not an oncologist, so I'm sure one will come along and dunk on my answer in terms of depth but that's the gist of it."], "text_urls": [[], [], []], "score": [7, 4, 3]}}, {"q_id": "7b4as1", "category": "Repost", "title": "What is depression and how is it different to being sad and unmotivated?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dpf4mol", "dpf3qrh", "dpf3wnx", "dpf4yhq", "dpf3qlj", "dpf5ibn", "dpf88tp", "dpf8q3e", "dpf9d98", "dpf99np", "dpf6dm3"], "text": ["> Sadness is a normal human emotion. We\u2019ve all experienced it and we all will again. Sadness is usually triggered by a difficult, hurtful, challenging, or disappointing event, experience, or situation. In other words, we tend to feel sad about something. This also means that when that something changes, when our emotional hurt fades, when we\u2019ve adjusted or gotten over the loss or disappointment, our sadness remits. > Depression is an abnormal emotional state, a mental illness that affects our thinking, emotions, perceptions, and behaviors in pervasive and chronic ways. When we\u2019re depressed we feel sad about everything. Depression does not necessarily require a difficult event or situation, a loss, or a change of circumstance as a trigger. In fact, it often occurs in the absence of any such triggers. People\u2019s lives on paper might be totally fine\u2014they would even admit this is true\u2014and yet they still feel horrible. > Depression colors all aspects of our lives, making everything less enjoyable, less interesting, less important, less lovable, and less worthwhile. Depression saps our energy, motivation, and ability to experience joy, pleasure, excitement, anticipation, satisfaction, connection, and meaning. All your thresholds tend to be lower. You\u2019re more impatient, quicker to anger and get frustrated, quicker to break down, and it takes you longer to bounce back from everything. [Source]( URL_0 )", "Depression and unmotivated can go hand in hand. Sadness can cause depression. There are a lot of different kinds of depression. Often people who suffer from chronic or repeating depression don't have a known emotional reason for the said depression (this is not counting people who faced trauma and abuse). I have Major depressive disorder, I occasionally get a week or two where I start to feel worthless, meaningless, unwanted, not valued, and I just want to escape people and beat myself up. Over years of therapy I've been unable to figure out any known cause or trigger. It just happens.", "Definitely not a doctor or psychologist, but I can give a patient point of view. I\u2019m not depressed now but I was for quite a long time. It\u2019s kind of like, I\u2019m bad at explaining... sleeping because you\u2019re too tired to stay awake and you know you\u2019ll feel better later vs sleeping because you\u2019re too tired of being awake. I guess it feels like being forced to do something as opposed to choosing to do something in a way. When you\u2019re sad you cry but when you\u2019re depressed you sleep. Everything feels hard and crying is way too much energy. You want to lie down and stare at nothing because you genuinely don\u2019t have enough energy to even be sad. I\u2019m sorry I tried super hard to explain that, it was better in my head.", "- Hey, how's it going? - Not good. Everything feels like a chore, I don't even want to draw, I have to remind myself to eat, I could barely brush my teeth this morning, I'm always tired, I don't know why I'm even doing anything. - Oh dear. You've been like this for a while, huh? What happened? - Nothing. Absolutely nothing. I just feel like shit for no reason. When my mum asks me how I am and I say something like \"meh, could be better...\" she often asks me why and there's absolutely nothing I can say because there IS no reason. Sure, sometimes I can point to some event that triggered my current depressive episode. But even then, it's usually something that shouldn't completely incapacitate me and take me weeks to get over. For depression to be diagnosed it has to last for at least two weeks and (severely) impair your ability to function. It's not (necessarily) feeling bad about something that happened, not feeling like doing something. It's a constant weight on you that makes it hard or impossible to do what you KNOW you should / need / even want to do. It's feeling low and at the same time not having a clue why. It's feeling like a lazy piece of crap because you can't get your shit together and clean your room and take out the trash even though you actually WANT to do it. I really do WANT to do the dishes every evening, it would take me 5 minutes maybe if I did - but far too often, especially during severe episodes, I just physically cannot do it, my body won't move, no matter how much I yell at myself, encourage myself, try to think of rewards for myself. Depression is \"in your head\" in the truest, literal sense. It's your brain chemistry not working as it should. Certain chemicals that are necessary for your brain to do what it needs to, for your brain's commands to properly be submitted to the rest of your body, aren't available in sufficient amount or not at all. Serotonin for example is part of a group of what's colloquially called \"happiness hormones\". Some depressed brains reabsorb any serotonin produced too quickly so the hormone can't take effect. That's where drugs called SSRI's come in: the acronym stands for selective serotonin reuptake inhibitors. They prevent the reuptake of the serotonin, so the hormone can do its job. So unlike what most people experience every once in a while, when they feel sad or unmotivated, this is an actual physiological issue.", "Let me preempt by saying I work in this field. Depression is persistently feeling sad until it affects your life negatively in some way. Bonus: For specific criteria read up on dsm or icd (mostly used for research/clinical work). Anyone can feel sad when something sad happens. This is normal, but normally we all recover somehow and life goes on. Being unmotivated can be a symptom of something, however, it by itself might not mean you have depression. There are many reasons (often normal) why one might be unmotivated to do something or everything, and again this might be normal.", "It\u2019s like every day is cloudy, all your extremities weigh 500lbs, you took five Benadryl and can\u2019t think and for some reason you don\u2019t care about anything. You\u2019re just there", "> Now and then, there\u2019s some task you just have to do. You really don\u2019t want to, you\u2019d rather put it off until later \u2014 but you\u2019re an adult, and you know it\u2019s important. So you suck it up, and you get it done. Maybe it\u2019s doing some D.I.Y. around the house, maybe it\u2019s going to the dentist, doing your taxes, whatever it is \u2014 you really don\u2019t want to do it but you make yourself do it anyway. --- > Imagine if each morning, you felt the way about getting up the way you did about that difficult task. This is different from just not wanting to get up \u2014 you want to get up, you know you need to get up, but it feels like a huge amount of effort. If it\u2019s now and then you could handle it, but instead it\u2019s every single morning. --- URL_0", "Honestly, the comic Hyperbole and a Half described it EXTREMELY well from a first-hand point of view. Be sure to read both parts. [part 1]( URL_0 ) [part 2]( URL_1 )", "So, being hungry kind of sucks, but it's usually a passing thing. You know where it comes from - lack of food, boredom, exercise, and so on - and you know what to do to remedy the feeling. You eat. There's a chemical mechanism in your body that tells you it wants food, and then when you give it food, it gives you positive feedback. Sadness is not too different. It sucks, but usually you know where it comes from, and you know what needs to happen in order to feel better. There's a chemical mechanism in your body that makes you sad, and when you get over the reason or something nice happens, it gives you positive feedback. Now imagine that you're hungry even though you just ate. And eating does nothing to fill you up. The chemical mechanism that drives you to do something and then rewards you for doing it is *broken*. You know exactly what you'd usually have to do to feel better, but it *doesn't work*. After a while, you stop doing those things, because they're pointless anyway. After a while longer, you feel like a failure because you know, rationally, that the task that you need solve is so *easy*. You enter into a vicious cycle because the mechanisms to beat you down still work perfectly, but the mechanisms that enable you to experience satisfaction and rewards do not. That's depression. One of the deadliest diseases that exist.", "Depression is the absence of emotion. Or a muffled sense of emotion. You can't feel happy even if you win something. You won't feel excited even if you get a free vacation to Paris. You might feel extremely sad though. But that too will grow muffled with time. You won't be too shocked by anything. It's a feeling of emptiness...or maybe see talks by Andrew Solomon on depression. He explains it really well.", "depression can present itself in so many different ways. For many, it turns into almost complete lack of energy and life force. For me, it shows itself through mild drug abuse and crying all the time because everything is horrible and I'm most horrible of all. It just depends on the person. I used to get sad, but it never resulted in laying in bed for weeks doing nothing but hating myself and everything around me. Many depressed people get unmotivated. The difference, I think, is sheer scale. Sadness, non motivation bug you for a bit, but depression will kick your ass for years on end if you don't take proper steps to help it."], "text_urls": [["https://www.psychologytoday.com/blog/the-squeaky-wheel/201510/the-important-difference-between-sadness-and-depression"], [], [], [], [], [], ["https://medium.com/@PhonicUK/why-cant-you-just-stop-being-sad-e6d73e390ecd"], ["http://hyperboleandahalf.blogspot.com/2011/10/adventures-in-depression.html", "http://hyperboleandahalf.blogspot.com/2013/05/depression-part-two.html"], [], [], []], "score": [311, 52, 42, 25, 12, 8, 7, 5, 5, 3, 3]}}, {"q_id": "7b7dfa", "category": "Repost", "title": "How do we know global warming is different than something like the \"Medieval Warm Period\", and that it is not just another anomaly?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dpfrw48"], "text": ["Frankly, we've already out done the Medieval warming by an order of magnitude today, and that's not including what we predict will happen, only how much the climate has already warmed. Rather than deeply explain it, I give you this webcomic: URL_0 (Your medieval warm period is listed by name near the bottom.)"], "text_urls": [["https://xkcd.com/1732/"]], "score": [9]}}, {"q_id": "7b7s32", "category": "Repost", "title": "How is it possible for us to know if a sound comes from the top or the bottom given that we only have two ears aligned horizontally?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dpfwx2j", "dpfvcar"], "text": ["The shape of your ears directs sound into your ear canals difforently based on the angle it comes in at. If you change the shape of your ears with something like play dough you lose this ablilty all togeather. Other animals like dogs aren't as good st this and so tilt their heads to get a better idea of what virtical angle the sound is coming from. Here is a great video by Smarter Every Day all about it: URL_0", "It's difficult for human to determine the height of a sound. Owls for example have an ear higher that the other to better be able to locate sounds"], "text_urls": [["https://m.youtube.com/watch?v=Oai7HUqncAA"], []], "score": [5, 4]}}, {"q_id": "7bbsj6", "category": "Repost", "title": "How did the 40 hour week, or 8 hours a day for 5 days, for jobs become the standard for a full time job, and why is anything less or more considered part-time or overtime respectively?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dpgrwdg"], "text": ["Early 20th century, for the US anyhow. There were a lot of protest for fair wages, and reasonable hours, after a while companies realized production and quality improved with workers who were not working 80 hours and starving."], "text_urls": [[]], "score": [4]}}, {"q_id": "7bdhvq", "category": "Repost", "title": "Legally how are Samsung allowed show Apple products and logos in their new advert?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dph2yso", "dph3lwa"], "text": ["There's no law prohibiting it. The same thing is common in car commercials showing how one brand has better technology or towing capacity than the competitors. Look at the ad where chevy trashes ford for their aluminum by dropping a load of bricks in each", "So long as it is not misleading advertising and only represents facts, most jurisdictions allow direct advertisment. Its just not always good for PR obviously cause its a direct jab at your competitors."], "text_urls": [[], []], "score": [4, 3]}}, {"q_id": "7belj4", "category": "Repost", "title": "If We control our brains, and our brains control our bodies. Why can't we control our bodies?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dphccvx"], "text": ["Because it is not useful to be able to manually control the beating of your heart. You always need your heart beating, so it is more efficient to just do it constantly, without conscious thought. Devoting a part of your brain to modifying the heart's behaviour manually would have been a waste of resources. Contrast this to breath control. Being able to not breathe in at a specific time *is* incredibly useful, for a creature that is unable to breathe in liquids but who sometimes finds themselves underwater. Being able to hold your breath is immensely useful, and mammals have acquired this adaptive trait long, long ago. And of course it still isn't 100% voluntary even if you try to assume direct control. Even if I say \"You are now manually breathing\" you can't just choose to stop breathing altogether - your body automatically starts breathing again before (or as) you pass out from lack of air."], "text_urls": [[]], "score": [5]}}, {"q_id": "7bid2l", "category": "Repost", "title": "In the age of Google, why does this subreddit exist?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dpi89bf", "dpibjtb", "dpi8kjj"], "text": ["The purpose of this sub is to provide simple explanations for things that may be too complex or otherwise difficult to wrap your mind around if you only relied on Google results. But sadly, many questions are posted with easily googleable answers but people are just lazy and want someone to tell them the answer.", "Googling is a skill, and you have to know how to find what you're looking for. Out here, people know how to phrase things directly, instead of making you look for an answer. Even then, an answer that at least *seems* right. Ever wonder why people in IT can fix computer issues easily? They are adept googlers. They know what to look for.", "depends. Sometimes it can take a while to find answers that make sense to you. I spend a lot of time in wikipedia-black holes of time. Some of the math/physics entries are bogged down with a lot of exacting tecno-talk and math equations. I often find myself dusting off parts of my brain that haven't been exercised in a while. I enjoy that stuff.....but not everyone wants to spend an hour trying to remember some terminology they learned many years ago just to answer a simple question. And trying to get a simple answer (that you trust) on some topics can be hard. Is global warming a hoax? Google it..... just try it - i did.....Donald Trump's twitter account came in the 2nd spot.... With the \"top 10\" that came up for you in your google search....do you now trust google to give you \"accurate\" information? or just the top 10 places they found the internet reading about that topic so they can sell targeted adds to your cookie tracked demographics.... now try URL_0 are your results different? yahoo? bing? screw it....ask reddit."], "text_urls": [[], [], ["duckduckgo.com"]], "score": [15, 6, 5]}}, {"q_id": "7bio0v", "category": "Repost", "title": "Why does the moon sometimes look much bigger on some nights than on other?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dpibfl6", "dpig3zt"], "text": ["[It's an optical illusion.]( URL_0 ) This happens when the moon is near the horizon and you can see other things in the same field of vision. But when it's overhead it doesn't look as large.", "There are two elements to this. * Perspective. When nearer the ground, you have a fixed point of reference relative to the moons size. By which I mean you have mountains, trees or buildings directly up against the moon in your vision which let you easily get a feel for its size. This makes it look a lot larger than it does when right up in the sky surrounded by nothing but black night sky. * The Moon's orbit (Supermoon) The moon doesn't orbit around the Earth in a perfect circle, it orbits in a slightly flattened circle, and the Earth isn't in the centre of that orbit anyway, not quite. Have a look at [this]( URL_0 ) image to see what I mean. There is a point where the Moon is closer to the Earth than it is anywhere else in its orbit, called the 'Perigee' on that map, and at that point the Moon will look up to 30% brighter, and almost 15% larger than it normally does. If you have a Supermoon situation combined with the moon being low towards the horizon, it'll look unusually huge compared to normal."], "text_urls": [["https://en.wikipedia.org/wiki/Moon_illusion"], ["https://solarsystem.nasa.gov/images/galleries/Earth_Orbit1.jpg"]], "score": [3, 3]}}, {"q_id": "7bjyki", "category": "Repost", "title": "Why did peppermint become the standard flavour for toothpaste and other things like that?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dpiki5z", "dpil4h9"], "text": ["A lot of reasons make it and its nearby variations like wintergreen or spearmint into popular flavourings in toothpaste and other breath-fresheners like gum or mints. In its earlier days, peppermint oil was easy to extract from natural easily-grown sources. It's associated with freshness. We've known about it for a very long time due to its ability to make a nice herbal tea, so when searching for something that would mask the chalkiness of otherwise-unflavoured toothpastes it was a natural hit. Its smell is associated with freshness and is excellent at masking or washing away the type of smells you get from not-quite-perfect oral hygiene, which is why it finds its way into a lot of desserts or dishes served as sides to strong food (e.g. yogourt-based sauces). And the \"cooling effect\" of the oil, which you can really feel if you get a massage involving it, makes your mouth feel cleaner than otherwise. Other flavourings such as clove oil, anise or cinnamon also work, but they're often stronger or unpleasant to more people so they're not as popular everywhere.", "As a side note, peppermint has historically been used as a treatment for abdominal/digestive issues. I wouldn't doubt that was considered."], "text_urls": [[], []], "score": [4, 3]}}, {"q_id": "7bkpkg", "category": "Repost", "title": "What makes spicy foods spicy?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dpiqap4"], "text": ["In most spicy foods, there is a chemical called Capsaicin, which is responsible for the spicy heat that comes off foods. It works in two ways: the first, is that it irritates, causing a slight pain sensation that activates nerves that otherwise aren't activated. The second is that it effects the temperature receptors on the tongue, TRPV1 (short for Transient Receptor Potential Vanilloid 1). It makes these receptors more sensitive to heat, essentially lowering the threshold that makes them send a signal to the brain indicating the mouth is \"hot.\" It's actually your own ambient mouth temperature that causes the heat, the Capsaicin just made the receptors more sensitive."], "text_urls": [[]], "score": [3]}}, {"q_id": "7bkyv7", "category": "Repost", "title": "body fat sensors on scales...how are they supposed to work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dpir70q", "dpirx4x", "dpirvdu"], "text": ["You enter your height and it knows your weight so it calculates your body mass index (BMI) to give you the inaccurate number that the BMI represents.", "Usually bio-impedence. It passes a current through your body up one leg and down the other. From this it can measure the resistance of your body. As fat contains less water than fat the higher your body fat the higher the resistance. It uses this along with your weight and height to give a very rough estimate of body fat%. Note however that things like what you have eaten that day and how hydrated you our can cause big changes in the reading.", "They measure the impedance of your body - URL_0"], "text_urls": [[], [], ["https://en.m.wikipedia.org/wiki/Bioelectrical_impedance_analysis"]], "score": [4, 4, 3]}}, {"q_id": "7bl529", "category": "Repost", "title": "how cd disks store data", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dpirxnl"], "text": ["It is an easier answer than you would think. CDs work exactly like records with two differences. 1) instead of translating waves they only have to care about an up or down position. 2) instead of a physical needle they use a laser. They are literally a long line of up and down positions (ones and zeros) that are wound in to a great big circle like a record with grooves so small you can\u2019t see."], "text_urls": [[]], "score": [3]}}, {"q_id": "7blm0n", "category": "Repost", "title": "Why is it that sitting for extended periods can cause blood clots but laying down sleeping for 6-8 hours a night doesn\u2019t?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dpivgkj", "dpj20r4", "dpj6th2", "dpjm3wb", "dpjem7v", "dpivhsc", "dpjpq5p", "dpj9nlx", "dpjugah", "dpivhfq", "dpj6fcp", "dpj6r2h", "dpjvkr4", "dpjhvri"], "text": ["When you sleep your blood does not have to flow upwards, your body is mostly straight and you are still moving alot in sleep. So If your leg is broken and you can't move a little your chance developing cloths is higher. That's why they give you shots in hospital every day. While sitting the legs aren't moved much, they are angled and the blood have to flow upwards.", "In sitting your blood has to work against gravity to go back up. In lying everything is the same level and doesn\u2019t have to work as hard to go to your feet and back. An extra fun fact: clots in your calves can go to your lungs and kill you that\u2019s why it is important to prevent them", "This is called a deep vein thrombosis and its more common after surgery, during travel, and in people who are at greater risk for it due to blood conditions and platelet count. The changes undergone in the body after having surgery can increase clotting and the chances of having a clot. This is made more likely by being more sedentary when recovering due to pain and mobility so it's important that people get up and walk at set schedules, even if it hurts. Patients are often given heparin injections to thin the blood after surgery, even going so far as to have patients self inject for days after being released from the hospital. Sitting for long periods isn't great for the body, but under normal conditions it isn't that bad. However when traveling for long periods of time, crammed into small and uncomfortable airline, train, or bus, seats, coupled with the seating position, circulation problems from seat design, and that at many times people are discouraged from getting out of their seat, people are more likely to develop them. Blood also tends to pool in the lower extremities when seated for long periods. Imagine a 20 hour flight to Australia in coach, where you can only get up and move around sparingly due to tightly packed seats. Outside of restroom breaks you might not get up at all. Laying down in bed doesn't put so much pressure on the thighs and cause blood to pool in the legs. It also doesn't affect circulation in any negative way unlike sitting. Standing still causes blood to pool in the lower limbs, however the action of walking helps with circulation and the muscle movements and motion help stimulate blood flow.", "To answer this, we should first take a look first at the circulatory system\u2019s method of flow. The blood comes out of the heart and into the aorta and arterial system. The arteries are much thicker because of their more robust tunica media layer. That\u2019s basically a smooth muscle layer that handles the high pressure, and in the case of the arterioles (medium sized arteries), it changes tone to effect your blood pressure. Once the blood goes through the capillary level (where it moves more slowly to accommodate oxygen, CO2, and metabolite diffusion), it goes into the venous system to make its journey back to the heart and lungs. ***CUE Part where DVTs (deep vein thromboses) happen The venous system is composed of very floppy vessels with valves to help prevent backflow of blood. It has a much thinner tunica media and it depends on the contraction of skeletal muscle (the voluntary muscles you use to walk) near it to help with blood flow when flow fights gravity (returns to the heart). If blood isn\u2019t moving fast enough, the clotting mechanisms kick in and you get a thrombus (fancy pants word for clot). When you\u2019re sleeping, your legs are more or less at the phlebostatic axis (on a horizontal plane with your heart), meaning return flow is *much* easier because you aren\u2019t fighting gravity to get that blood back up to the heart. When you sleep, your body moves a tiny bit to keep venous return flow going, but the gravity is your most influential variable. With the gravity being alleviated, you aren\u2019t usually laying down long enough to make a difference. If you\u2019re down for more than a day or two, we start to treat it a bit. *In the hospital, we use some anticoagulants (anti-clot meds) and powered compression devices to simulate skeletal muscle contraction. This is mostly because people are in bed for days at a time without a lot of motion while recovering. The tops of the beds also tilt up, so gravity makes an appearance again. This is why nurses put pillows under the knees or slightly elevate the legs (some nicer beds can do this) so the hips are the lowest part of the body (not with a straight knee as that actually inhibits flow as well\u2014I\u2019ll get into that at the bottom). Minimizing the effects of gravity helps the venous circulation even more than the compression machines by themselves. Quadriplegic people bound to wheelchairs often have tilt chairs because they get almost no skeletal muscle activity in their whole body. **Answer time/ TL;DR** When you\u2019re sitting for prolonged periods, your skeletal muscle activity is low, but because you\u2019re flighting gravity, your blood has a tendency to push into the venous walls and expand them (remember they\u2019re floppy), causing a decrease in flow velocity due to a widened vessel. It\u2019s like taking the sprayer nozzle off a garden hose. The change in diameter causes an inverse change with regards to flow even though the same amount of fluid is going through. When the blood is allowed to slow down like this, it causes an increased risk of clot. You may be wondering why a clot is so bad. It can break away and float to your lung, causing a Pulmonary Embolus (PE) and killing part of your lung. It could float to your brain and give you a massive stroke. It could also block your coronary circulation and give you a heart attack. All three of those can kill you. Getting up frequently on flights helps decrease the risk for clots. Couple that with compression socks/sleeves/tights (the leg is more at risk than the thigh and is the more important part for compression), and that usually reduces the risk of clot formation *dramatically*. Also to note, compression shorts aren\u2019t a good idea because they prevent a backflow as the blood goes from the uncompressed leg to the compressed thigh. Distal is more important, so the compression should be greater there and should decrease as it gets more proximal to your body (distal = further from heart, proximal = closer). If you have clotting disorders, consult your physician before flying. If you\u2019re on birth control or pregnant, it\u2019s a good idea to get your PTT/INR checked regularly (clotting factors). This is purely educational and not a substitute for medical advice. *As promised: the straight knees thing! Straight knees actually cause the veins to bend a tight (but small) turn. Think of it as a kink in the garden hose that causes resistance in the vessel. When people pass out from standing with straight legs, this is why.* Hope this helped! I love physiology! Let me know if you have questions! Again, this is just for educational purposes. Please excuse any typos/autocorrects. I did this on my mobile. Edit: Yay Gold!!! Thank you so much kind stranger!!!! I\u2019m stoked to figure out what it does \ud83d\ude01", "I have a followup ELI5 - When people wear the compression socks to help with circulation, how does it not just cut off or restrict blood circulation to the feet? Are compression sleeves a good thing to wear in general if you sit for long periods of time? Does it actually help?", "Sitting is not a \"natural\" position - we haven't been doing it for very long in evolutionary terms, so it can cause problems due to how our bodies are shaped. For most of human history, and still in very poor and ancient cultures, people would squat instead of sitting. We evolved buttocks because they store fat to burn when walking or running, not for padding to sit on. Lying down, however, *is* a natural posture for us that doesn't interfere as much with circulation.", "How do people who are chronically confined to a wheelchair deal with this?", "Well laying down for an extended period will eventually also lead to thrombosis. However sleeping usually does not trigger thrombosis because: 1. While you are sleeping you still sometimes move your legs, activating your muscle pumps and reducing the risk of thrombosis. 2. Blood does not have to flow upwards like in a supine position. And thrombosis after sitting for extended periods of time is usually in tight spaces (e.g. planes), where the veins are additionally compressed externally - this is also known as \u201ceconomy class syndrome\u201d.", "See, I'm a hemophiliac, which means my blood is super shitty at clotting. That means I actually have an advantage when it comes to any task or activity that is sedentary for long periods of time! Can't build up a deadly blood clot if I can't can't clot to begin with! That pretty much makes me the Ubermensch of any office setting. I'm just going to sit here and smile at my screen smugly knowing that there's nothing anyone can say at this point to deliver any sort of come-uppance.", "It can? Maybe happens less Often but th\u00e9 Point being is that you need to move to lower it's risk. If you wake up, site for 8 hours and go to bed again you higher th\u00e9 risk. Maybe also because blood lowers to the legs when sitting. More blood there with less pressure on it. Cloths can form more easily?", "Neglecting the aspects of moving and such that everyone else is mentioning, Here's a basic principle. Pressure = Force/Area. The more area you have, the less force that area is subject to. Bloodclots are caused when the pressure forces the blood vessels closed, or prevent flow of blood. When you are sitting, the pressure(on just your butt area) on such a small area prevent blood from moving and therefore, you end up with blood clots. When you are sleeping, the pressure is distributed much more evenly. (more surface area, Your back, legs, head, etc.) Now to the sciency mathy parts. rounded to really nice even numbers just because i'm lazy, but its close enough. If you divide you butt are by weight. That comes out to the pressure you exert on the are. It averages out to something like 15mm hg (there's math behind this and i'm pulling number out of my butt.. literally :P ) Now we all know that flow needs a pressure difference in order to move. (gravity, pressure, concentration, etc) The pressure difference between the arteries and the venous system is just about 10 mmhg. So.. when you sit down, you exert 15 mmhg of additional pressure prevent blood flow to leave an area, and that's why you end up with blood clots. When sleeping, the area is more distributed, the pressure less, and less blood clots. Onto the Yes i know.. but what about... Bedsores. (yes.. certain areas carry more weight. If you don't end up moving, blood clots and flow issues. The LEGS MAN, What about the legs!!!! Her legs, and right where her legs meet her back. That - actually that whole area. That and - and above it. Gravity. Yes.. Gravity plays a part. Reminds me of a story...", "Sitting doesn't cause blood clots by itself. The danger of a pulmonary embolism is when someone has an injury like a torn calf muscle and they go on say a long plane flight, a blood clot could grow larger than usual because of lack of movement and then break free, travelling to the heart and stopping blood flow causing a heart attack. Normally the blood clot never gets that big because with regular movement smaller bits will break free and get absorbed by the body. At least that's how it was explained to me by a doctor that was an expert witness in a legal case where I had to design the visual representation (animation and stills) for the jury. Dude was suing his doctor because he flew to Australia with a tennis injury and almost died because of a pulmonary embolism. Said his doctor didn't properly warn him to get up and walk around every so often to keep the blood clot from getting too big. Don't recall if he won or not, but that's why they say to get up and walk around on long flights, in case you have an injury that could cause a clot to grow while sitting for long periods. I have no idea if this is a danger while sleeping too, but I would think that with normal sleep movement it wouldn't be an issue since you're constantly changing positions while asleep.", "Physiologist here: Blood tends to clot when it stagnates (i.e. isn't flowing very fast). Your heart pumps blood from it to the rest of the body under high pressure in arteries. By the time the blood reaches the distant parts of your body (e.g. fingers, toes) and passes through the capillary bed (small network of blood vessels that connect arteries and veins), there is very little blood pressure remaining - not enough, for example, to move blood from the feet to the heart when the blood is working against gravity (when you are standing or seated). Blood is mostly water (it's heavy) and it takes quite a bit of pressure to move it from your feet to your heart when you are sitting or standing - as your heart is located at least a meter or more above your feet. To help move blood back to the heart when you are sitting/standing, your veins have one-way valves in them. Muscles surrounding these veins contract, squeeze the vein, and the one-way valve ensures that blood in the vein only moves towards the heart. When you are normally sitting or standing, periodically moving your legs causes your leg muscles to contract, squeeze veins that run through/near them and help to pump blood back to the heart. When you're seated , your leg muscles are normally relaxed. Those leg muscles, therefore, aren't frequently contracting and relaxing as when you are standing/walking and shifting your feet; they aren't pumping a lot of blood back to the heart. Blood tends to pool in your feet/lower legs, and this can cause blood clots to form. When you're sleeping, you typically are lying down. Blood in your lower extremities is typically only a few centimeters lower than your heart. It doesn't, therefore, take much energy to get that blood back to the heart. The small amount of pressure in your veins is typically sufficient to push the blood from your lower extremities to your heart when you are lying down.", "Is sitting down cross legged just as bad as sifting down normally?"], "text_urls": [[], [], [], [], [], [], [], [], [], [], [], [], [], []], "score": [4914, 970, 228, 98, 70, 24, 22, 17, 14, 13, 7, 6, 5, 3]}}, {"q_id": "7bo00y", "category": "Repost", "title": "If babies can't provide feedback to eye doctors, how do eye doctors know what type of specs to give them?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dpjfmyv", "dpjfh81", "dpjfv97"], "text": ["They scan the retina through a machine. Since you have to look through the eyes lens to see the retina, that also gives plenty of information about the lens's properties. This works fine for adults too, and they'll often do it to get a ballpark estimation before you start trying different lenses. The thing is, adults are a bit more picky than a baby, and if something is a tiny bit out of focus it's gonna be annoying. The machine can't quite detect these small imperfections, and sometimes its just down to personal taste, so it's best to let people decide for themselves what looks best. Babies don't really care about these small differences.", "I had this question, too. The eye doctor told me the instruments they use are able to tell what prescription a baby would require.", "There is a family of \"automatic\" prescription checking machines. Most of them work on the same principle, you look at a high contrast panorama image, like a deeply colored hot air balloon in a light blue sky. The machine that projects the image also contains a camera that looks through the optics to sense the image on the back of your eyeball. The optics are varied, under computer control, changing their focus until the sensor detects a sharply formed image on the back of your eyeball. This optics adjustment measures the correction needed to make your eye focus at distance. Since children's eyes work the same way, they don't need to \"participate\"."], "text_urls": [[], [], []], "score": [5, 3, 3]}}, {"q_id": "7bq195", "category": "Repost", "title": "Why do you get nauseous when you read in a car?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dpjwkd2"], "text": ["Your brain doesn't like the discrepancy between what your eyes see and what your body feels. You have an organ in each ear that senses changes in acceleration. When you go around a corner in a car, you body senses this but if you're just looking at a book in the car, your eyes don't see this corner. According to your eyes, you're not in motion. Your brain can't account for both and it gets confused, making you nauseous. It's far less likely to happen on planes boats and trains since they mostly travel in straight lines."], "text_urls": [[]], "score": [3]}}, {"q_id": "7bsjjb", "category": "Repost", "title": "Why are players from South Korea so dominant in video games?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dpkf4bt", "dpkixof"], "text": ["Not especially MOBAs. They dominate Starcraft BW and Starcraft II. They basically dominate any games they start investing real time on. They currently dominate what, SC, LoL, OW (the games I know of). I think it's mostly cultural. Asians = > Work hard, for yourself, your family + with all that eSport knowledge and background they have solid infrastructure around players.", "There are many reasons: - the country is small but densely populated. Servers placed in Seoul can often provide players with pings < 10ms - essentially the same as in a LAN. For MOBAs this means that pro players get to practice EVERY DAY in the very environment they will play on stage in tournaments. At this level of play, having a ping of 50 or even 80 (which are common for many servers in EU or the US) is essentially like playing a different game. This makes their practice for tournaments less efficient. - Esports (competitive video games) have a long tradition in Korea. Because of that, they are much more accepted and viewed as \"legitimate\". People can actually envision having a career in the field. While in most other countries it is still viewed as a hobby and even pro players always have to keep their future in mind. - Because of that long tradition, Korea also has way more experience when it comes to training, coaching, etc. - for some reason Koreans are much more likely to play this kind of video game. Take League of Legends, the \"tiny\" Korea has roughly the same playerbase in that game as the much larger US and is comparable even to the entire EU. To summarize: - you have a huge pool of potentials - the environment/working conditions are better than in pretty much any other region - you have experienced coaches & infrastructure - \"soft skills\" like the fabled work ethics and more importantly the willingness to listen to elders (coaches) compared to many western players."], "text_urls": [[], []], "score": [3, 3]}}, {"q_id": "7bsk8j", "category": "Repost", "title": "How does Google Maps navigation provide information regarding traffic, accidents etc. so fast and accurately?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dpkfhlo", "dpkfqwn"], "text": ["You might know that google is one of the driving forces behind the Android system for smartphones. They have all their services installed, and many people use those services including stuff like location based services. Now for that kind of service requires as you might guess, the current location of that person. One persons data can be used mostly for services for that one person, but google has access to many data points. Now imagine the google server sees 300 people traveling on a highway at normal speed. Well then you can already start doing some calculations with other informations you might know, like the average amount of android devices in an area to interpolate how much traffic there is. And then, those 300 data points suddenly all slow down while on the highway. There aren't that many possiblities why this could happen. If they speed up after a certain point, you can also start to pinpoint where the problem is. You can opt-out of those types of data-gathering, but many choose not to for one reason or another. Aslong as enough people send their data, they can use that data to calculate all sorts of useful stuff.", "Google maps has access to data from every user of Google maps, Waze, and Android in addition to traffic reports put out by various agencies. That\u2019s a lot of real-time data showing location, speed, traffic density."], "text_urls": [[], []], "score": [8, 3]}}, {"q_id": "7bt08p", "category": "Repost", "title": "How do we get vitamin D from the sun? There's no vitamins in light so how does it work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dpki0wa"], "text": ["The majority of animals produce Vitamin D (actually a group of compounds known as secosteroids) through photosynthesis, meaning synthesis through light exposure. The human body requires Vitamin D3 and D2 primarily. The precursor to Vitamin D3 is called 7-dehydrocholesterol, which the body can make on its own - when that chemical is exposed to sunlight, specifically UV light, in the skin, it undergoes photosynthesis to produce Vitamin D3."], "text_urls": [[]], "score": [3]}}, {"q_id": "7bved3", "category": "Repost", "title": "How auto-dimming rearview mirrors work", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dpl1kzf"], "text": ["Yarr! Yer not alone in askin', and kind strangers have explained: 1. [ELI5: how do auto-dimming rearview mirrors work? ]( URL_0 ) 1. [ELI5: how do autodimming mirrors work? ]( URL_1 )"], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/3btuom/eli5_how_do_autodimming_rearview_mirrors_work/", "https://www.reddit.com/r/explainlikeimfive/comments/6zgub4/eli5_how_do_autodimming_mirrors_work/"]], "score": [4]}}, {"q_id": "7bvpb9", "category": "Repost", "title": "How is the sun able to burn for millions(?) of years?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dpl43kv", "dpl71wq"], "text": ["The sun doesn't burn it fuses atoms to release energy. At high enough pressure, like in the center of a star, two Hydrogen nuclei get squeezed into one to make a Helium nuclei. When this happens a small amount of matter is lost and turns into an enormous amount of energy (Einstein's equation Energy= mass times the speed of light^2). There is enough hydrogen fuel in the sun to keep it fusing for about 9 billion years.", "The Sun burns about 6x10^(11) kgs of hydrogen every second. Luckily, the Sun has about 1.45x10^(30) kgs of hydrogen to burn. Thus, the Sun has enough hydrogen to live for about 2.4x10^(18) seconds, or about 76 billion years. Of course, the majority of that hydrogen will not be burned before the Sun dies, but the point is that compared to the size of the Sun, the amount of hydrogen burnt is minuscule. If you remove 6 L/sec from the world's oceans (The Amazon River discharges about 200 ML/sec), you'll be emptying the oceans at nearly the same rate that the sun is burning through its hydrogen reserves."], "text_urls": [[], []], "score": [9, 3]}}, {"q_id": "7bxkwp", "category": "Repost", "title": "Why does using a scissor to put pressure along a ribbon cause it to curl up?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dpll3ez"], "text": ["You actually cause an asymmetrical stretching of the material- The far side of the ribbon is being stretched more than the facing side, so it bends. URL_0"], "text_urls": [["https://www.scientificamerican.com/article/secret-of-ribbon-curling/"]], "score": [12]}}, {"q_id": "7c13zz", "category": "Repost", "title": "Why do we swing our arms back and forth as we walk?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dpmbdkx", "dpmbfsd"], "text": ["Your arms naturally swing when walking. Not swinging your arms when walking engages your muscles and might not be as comfortable.", "Because it balances our body to keep walking straight Here is a great article on wiki: URL_0"], "text_urls": [[], ["https://en.m.wikipedia.org/wiki/Arm_swing_in_human_locomotion"]], "score": [4, 3]}}, {"q_id": "7c1oyt", "category": "Repost", "title": "Why does everything seem more quiet when it snows?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dpmg01a", "dpmgbqs", "dpmg2l5"], "text": ["Snow is a \"soft\" substance. It does not reflect sound waves well. When the sound vibrates the outer layer of the snow, the air pockets and the general weakness of a snow flake means that much of the energy is absorbed by deforming the snowflake. Since the sound you hear is the sum of the sound that comes directly to you and the sound that is reflected to you, covering the outside with a sound-absorbing substance greatly reduces the sound reflected to you.", "Snowflakes have open space in their structure acting as a sound buffer. This reduces noise. Sound travels in waves and needs to vibrate the molecules in the solids, liquids or gasses to be transmitted. Sounds also travel faster in warmer conditions, so air temperature helps to slow down or speed up the waves, changing what is heard. If there are objects in the way, sound can be dampened, reducing what is heard. Snowflakes do just that! As snow begins to melt and change shape, sounds change yet again. When snow melts, the space in between each crystal is reduced as well as the buffering property, and the silence of a fresh snow goes away. In fact, as snow turns into ice, it can actually make sounds louder because it will reflect sound waves instead of absorbing them.", "Snow contains a lot of air cavities, these trap sound waves and prevent some of the reflection. If you've seen those quiet rooms with foam cones on the walls, snow kind of operates in a similar manner."], "text_urls": [[], [], []], "score": [49, 6, 3]}}, {"q_id": "7c6qi0", "category": "Repost", "title": "Why do paper towels become more transparent when they are wet?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dpnnnyq"], "text": ["Refractive index matching. Paper is made up of cellulose fibers and air pockets. Air and cellulose have very different refractive indices, and light trends to scatter each time it encounters a refractive index change. Water is much closer in index to paper, so there is less scattering."], "text_urls": [[]], "score": [3]}}, {"q_id": "7c8qrs", "category": "Repost", "title": "The financial crisis of 2008", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dpnzw8n"], "text": ["Disclaimer: I'm taking all of this straight out of The Big Short. It's worth watching - great movie and it's basically an ELI5 itself. Basically, there's a form of security that's, well, secured by mortgages. It's been around for decades, and basically consists of a bunch of mortgages bundled together. The reasoning is that everybody pays their mortgage, so it's \"safe\" to bet on it. But there's only so many homes in the world, and only so many mortgages to bundle together into mortgage-backed securities. They had previously only included mortgages from trustworthy people who had good credit, but now they've run out of those people. So, these mortgage-backed securities started including B rated loans, meaning less trustworthy people who might not pay them back. Some people got smart and realized this, and they started betting against the market. They assumed when the securities started consisting of mostly subprime mortgages, the bubble would burst. But that didn't happen at first, because the loans were still rated highly. Basically, the companies that accredit the mortgages were getting bribed/extorted by investment banks to issue A ratings for loans that were, frankly, crappy. We're talking stripper-in-miami-with-five-mortgages-takes-out-a-loan-to-buy-another-house kind of crappy. This kept things going for a while, but eventually these people were unable to pay back their mortgages and defaulted, and that's what caused the collapse."], "text_urls": [[]], "score": [3]}}, {"q_id": "7c8wll", "category": "Repost", "title": "How do windmills work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dpo1h3d"], "text": ["Windmills are giant mechanical 'pestle and mortar' devices. Wind pushes the rotors, which are angled, meaning the wind forces them to spin. The spinning rotors are connected to a series of gears, eventually leading to a giant 'pestle and mortar' type device. The giant 'pestle and mortar' device grinds with great force, allowing for the easy production of flour and other commodities."], "text_urls": [[]], "score": [6]}}, {"q_id": "7cbe3j", "category": "Repost", "title": "Why do our Stomachs Rumble?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dpokf70", "dpoqphe"], "text": ["Fluids and gasses are moving about in a really foldy tube which contracts to move things around. It's pure mechanical noise of the process.", "It's called peristalsis. Your intestines/stomach do this to move food through your digestive system. The rumbling happens because peristalsis occurs periodically even when there's no food in you, to make sure your stomach was totally emptied whenever you might eat something"], "text_urls": [[], []], "score": [60, 11]}}, {"q_id": "7cd5g1", "category": "Repost", "title": ". Why does alcohol make you pee?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dpp068c"], "text": ["ADH (a hormone) is made by the hypothalamus (part of the brain) and stored in the kidneys. It tells the kidneys how much water to absorb. Alcohol inhibits ADH. Instead of the water being absorbed it goes to the bladder which makes you pee more often."], "text_urls": [[]], "score": [13]}}, {"q_id": "7cdx53", "category": "Repost", "title": "Why do some noises (like nails on a chalkboard) make us cringe?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dpp9hrz"], "text": ["Best answer I have is the variation of the different frequencies you create when you scrape a plate/chalkboard, crush styrofoam, etc. It can trigger the unpleasant feeling for humans. The frequency is different for everyone (just like how most children can hear a dog whistle but adults can't) but it lies somewhere between 2,000-4,000 Hz."], "text_urls": [[]], "score": [4]}}, {"q_id": "7ce5da", "category": "Repost", "title": "Where does dust come from? and what it is made of?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dpp8chd", "dppk2uf"], "text": ["Depends where you are. In a home dust is mostly human skin. In a granary it's mostly wheat or corn or beans, seeds maybe sunflowers. Could be rye or barley.", "It comes through the window It comes through the floor It comes through the roof and It comes through the door Dust is everywhere Sweep."], "text_urls": [[], []], "score": [19, 13]}}, {"q_id": "7cffdn", "category": "Repost", "title": "How does fridges or freezers work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dppgm3d", "dppicjb", "dppjxrt", "dpphvmo"], "text": ["Have you ever held a can of compressed air while you pressed the trigger? The can gets really cold. When compressed gas is released the container cools. Imagine a loop of pipe. There is a very small valve on one side and a pump on the other. The pump pressurizes the coolant. The valve creates the same reaction of pressure being released. So the side where the pressure is released is cold, but the side with the pump is hot. That's why they put the hot pump on the outside (of the air conditioner or refrigerator). And the cold valve on the inside.", "Imagine you have a collapsible container of some gas at room temperature, and you begin squeezing it. You're doing *work* on it, which means you're transferring *energy* into it. The only place that energy can go is into the temperature of the gas: i.e., it gets hotter. Now you let the outside air cool the container back down to room temperature. Then you relax your grip on the container and let it expand again. This time the gas is doing work on your hands, and the only place that energy can come from is the temperature of the gas -- so it gets *below* room temperature. In the fridge, a gas goes through a compressor to accomplish the first step. The high-temp gas then runs through tubes outside the fridge in back, where the air cools it. Then it goes through a small orifice, which accomplishes the second step; then it runs through tubes inside the fridge, picking up heat from the contents, and finally back to the compressor. Lather, rinse, repeat.", "Engineering student currently taking thermodynamics. Fridges and freezers are what\u2019s called thermopumps. Essentially, heat is the kinetic energy of atoms and molecules wizzing and vibrating. As long as a substance is above absolute 0, there is always heat within it. A thermopump sucks in the heat from a region (the inside of your fridge) and dissipates it in another (your kitchen). In nature, heat only moves from hot to cold regions, so how does a thermopump manages to do the opposite? We achieve this by having a refrigerant substance run through a system of tubes, the substance is choosen such that it can be vaporized and liquified easily. There are heat transfers that come with the phase changes (liquid to vapor and vice versa). Last bit of science we need to be aware of to understand the themopump is the fact that not only temperature can induce a phase change, pressure is equally important. In everyday life everything happens at 100kPa so we don\u2019t notice it as much, but water will boil under 100C in high altitude where the pressure is lower. So our refrigerant can be boiled by simply changing the pressure. So now we can get a more applied idea of how the thermopump works. The refrigerant will start as a cold low pressure liquid (colder than the inside of your fridge) that will go through long winding tubes in the inside of your fridge, sucking out the heat to undergo a phase change, turning into vapor. Then enter the compressor, the part of your fridge that requires power, to raise the pressure and temperature of the vapor. It will then go through long winding tubes again, this time on the outside of fridge (your kitchen). The vapor will liquify and thus pouring alot of the heat it gathered earlier inside the fridge, into your kitchen. The high pressure hot liquid will then go through an expansion valve (which will essentially lower the pressure and temperature). Bringing us back to the low pressure cold liquid from the begining. Thus completing the refrigeration cycle. The pressure changes are done to change the phase change point of the refridgerant to the ambiant temperature of both regions. This can be reversed to heat up a home. These systems are more efficient than traditional electrical heaters because they use energy moving heat rather than just generating it. TL;DR: They move the heat inside your fridge/freezer to your kitchen by playing with the refrigerant\u2019s pressure and temperature and phase changes.", "When you compress air (Make a volume of air take up less space), you heat it up. This happens because all the energy is compressed into a smaller volume. When you decompress air, the opposite happens. This is charles law. So, they take a refrigerant, compress it a lot, then cool it off with room temperature air. They then decompress it and it becomes very cold. You can do this with regular air (nitrogen, oxygen, and carbon dioxide), but it doesn't work as well. Then they run air in the fridge across the cold heat exchanger, which warms the refrigerant up. Rinse Repeat. Air conditioners in your house and car work in the exact same way, but on a larger system."], "text_urls": [[], [], [], []], "score": [45, 14, 6, 5]}}, {"q_id": "7cg90c", "category": "Repost", "title": "How do pills know where to go?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dppm04x"], "text": ["They don't, they more or less just (in general) go everywhere in your body via the bloodstream. They just float around their bloodstream until their chemical composition happens to fit somewhere, and that's where they end up. Imagine a round peg going around your body. it will try to fit into every hole it comes across. Eventually it will find the round hole where it fits, but there might be a lot of other combinations it attempted in the meantime. This is among the reasons why Chemo therapy is so invasive, the chemicals being used don't know what are cancer cells and what are healthy cells. They more or less just attack everything with the strategy of killing the cancer before either it or the chemicals kill you."], "text_urls": [[]], "score": [10]}}, {"q_id": "7cg9gx", "category": "Repost", "title": "How are receipes for Coca-Cola, KFC and others kept secret with so many people involved in production?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dppm40p", "dpporiu", "dppo0bv", "dppomdb", "dppnivy", "dppm6uu", "dppo2oq"], "text": ["compartmentalization, Have no one person know the whole recipe. KFC has the original recipe in a double locked safe with vials of the 11 herbs and spices, and 2 factories that mix them separately before being combined. Coke numbers its ingredients from 1 to 9 with 1 though 4 being publicly known whist 5 though 9 are unknown, there is also considerable speculation on what ingredient 7x is. That could be the main ingredient or just a publicity stunt to cause speculation on why it has the x.", "Of *course* people know the ingredients in Coca-Cola. Anyone working on the shipping dock knows exactly what goes into the secret formula. Even the notorious \"7x\" ingredient has a whole procurement department who negotiates with suppliers and arranges its shipping. It's not the Manhattan Project over there. But the secret formula is more than a list of ingredients. For example, Coke has quite a bit of distilled orange oil in it. How hot and long you run the still has a huge impact on the drink's eventual flavor. Same thing goes for the coca extraction, and the nutmeg-cinnamon preparation--little changes in procedure can make a big difference. That's why Sam's Choice Cola always tastes a little off. It's the same ingredients, processed roughly the same way. But it's never quite the *same*. You'd have to rebuild Coke's entire production line and supply chain to make a true bottle of Coca-Cola. EDIT: But yeah, they almost certainly keep secret records about the *process* (for example, they would need a record of the ideal viscosity and PH of the orange oil distillate, in case the still breaks and they need to repair it back to original condition). I imagine very few people have access to the whole archive--ie, the quality control guy that verifies the orange oil blend probably has no idea about how to prepare the nutmeg mix. So somewhere in a safe, there is likely the information necessary to make a much better Coke knockoff. But it's a lot more complicated than the list of ingredients. It would be binders full of chemical analysis and procedural notes.", "They aren\u2019t actually secret. Many companies have already worked out what the recipes are. It\u2019s the brand that can\u2019t be replicated, and it\u2019s the brand that people buy.", "I worked at a Coca-Cola bottling plant during summers in high school. I was a Syrup Technician. (No joke, that was my actual title) The formula for making coke syrup is as follows: - Man sized barrel number 1 shipped in from a Caribbean factory - Man sized barrel number 2 shipped in from a completely different factory on a different island - 5000 gallons of corn syrup and water That's how its a secret. The barrels were from different places, unlabeled, except for \"#1\" & \"#2\", plain white plastic.", "Even if someone knew the recipe, it wouldn't matter all that much. Of the ingredients, such as cinnamon, carry widely in taste and wildly effect the taste of composite flavor profiles like Coca-Cola when they are changed even a small amount. All ingredients in Coca-Cola are sourced a single way. You couldn't take the recipe and recreate it.", "From my understanding every step along the way is compartmentalized. Just like when the us built the atom bomb during ww2. All the departments were working on its own part but not really understanding the whole. For instance kfc is not its own company but owned by a parent company thus when they buy the 11 secret herbs and spices from various distributors its hard to tell where its gonna go.", "Compartmentalization, to try and prevent knowledge of the whole thing, and non disclosure agreements to keep employees from talking even to each other. Happens all the time in corporate environments."], "text_urls": [[], [], [], [], [], [], []], "score": [227, 56, 41, 33, 11, 9, 3]}}, {"q_id": "7cknz9", "category": "Repost", "title": "Why is it that people like celebrities can admit to committing crimes in autobiographies but not be penalized?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dpqngnc", "dpqolu0"], "text": ["Same way people can talk about crime in a song, etc. It's not a confessional testifying under oath, so as far as anyone is concerned, it's fiction.", "Most crimes have a statute of limitation. Such as 5 years for vandalizing a storefront. (Numbers pulled from butt) So you can freely admit something after a period of time without fear of being arrested."], "text_urls": [[], []], "score": [6, 3]}}, {"q_id": "7cq6ed", "category": "Repost", "title": "The difference between race, ethnicity, and nationality.", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dprrzef"], "text": ["Race is your skin color and other typical features of a group. Ethnicity is a combination of race and cultural heritage. Nationality is citizenship to a particular nation or state."], "text_urls": [[]], "score": [3]}}, {"q_id": "7cu0fw", "category": "Repost", "title": "Why do we have dominant hands?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dpsp06q", "dpsov9n", "dpsobb1"], "text": ["Also, why is the herd dominant - side usually the right? Are there places in there world where left-handedness is the norm?", "The best answer i've heard for this has to do with language. As humans developed language it was usually developed in one side of the brain (the left). Before this point there is no clear evidence that humans were right hand dominant. After this point we have evidence that most humans are right hand dominant. The left hemisphere of your brain also controls the right side of your body. The hypothesis is that your right hand (and foot) becoming dominant was a side effect of this side of the brain doing more processing. There is also evidence that people who process language on the right side of their brain tend to be left handed. As for people who process language on their left side of the brain and are left handed? I don't know.", "In addition to OPs question does the same go for legs? I remember snowboarding for the first time and goofy was the only way. My right leg had to be in front. So what exactly causes that?"], "text_urls": [[], [], []], "score": [4, 4, 3]}}, {"q_id": "7cudtd", "category": "Repost", "title": "If technology is advancing exponentially, why is a new computer only marginally faster than my three year old computer?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dpsqb3z", "dpsqvnd", "dpsq4he", "dpsqkfc"], "text": ["How are you measuring speed? Time it takes to boot up your system? Hard drive speed increased significantly between HDDs and SSDs but is largely on the same level between those. FPS in a game? That should have increased significantly. Time it takes to respond to your input? That is largely a peripheral issue with only minor improvements.", "Probably because you're not buying the latest technology. For example, three years ago a cutting edge i7-5960X (at the time the \"fastest desktop CPU ever\") scores 15994 on cpubenchmark. The fastest current desktop CPU scores over 27000. That certainly isn't marginal. Comparing GPU's from the same period also shows a significant increase in speed. The reason your new computer is only marginally faster is because that's what the market wants. Most people don't want the latest technology at huge cost. They'd rather have cheap and cheerful that does the job.", "It's disingenuous for anyone to claim \"tech is advancing exponentially.\" There's no single value for the quality of our technology, so all it really means is that the new stuff being made depends on the most recent discoveries also being present. The changes might be more significant/visible as AI continues to be integrated. I've already seen some crazy stuff it can do, and each incremental success contributes to the next.", "The answer is that while speed was proceeding exponentially before, the rate of progress slowed down when they hit physics problems we could not easily solve. Space between the bits of the chips were getting so small that weird quantum mechanics was causing electrons to teleport and short circuit the device. The CPUs were running so fast they were practically melting unless you used liquids to cool them down. We sustained some speed increases by working with the stuff we had alot better, or just adding more of the stuff we already had. But until we solve those problems progress is going to be much slower. Once we solve those problems, or find a different way of doing things, we get exponential growth again. This happens with pretty much any technology. For example, compare a gun made in 1887, 1917, 1947, 1997 and 2017. 1887 - > 1917 HOLY SHIT IT NOW SHOOTS MULTIPLE TIMES 1917 - > 1947 HOLY SHIT IT'S LIKE A RIFLE AND A MACHINE GUN HAD A BABY 1947 - > 1997 Uhh, it's made of plastic I guess, oh and it's a bull pup now, thats kinda cool 1997- > 2017 There was a change?"], "text_urls": [[], [], [], []], "score": [8, 5, 4, 4]}}, {"q_id": "7cushe", "category": "Repost", "title": "Why do we lose Appetite when we are anxious/Nervous?", "title_urls": {"url": []}, "selftext": "Always happens and it would be awesome to dig a bit into the science of it as well.", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dpst6l0", "dpsusqp", "dpsv6k8", "dpsvb69", "dpt53ya", "dpsy67x", "dpsywy8", "dpsx392", "dptantj", "dpsxokm", "dptd7na", "dpt72om", "dpt2arq", "dptlf8b", "dptbm4i"], "text": ["Much like the 'Fight or Flight' response related to real-world dangers and how we react to them, the brain has a hard time telling difference between a physical threat or a psychological one. Anxiety and Nervousness can be as frightening mentally as a dark alley way or a guy with a knife across the street. When your body goes into 'Fight or Flight' blood is moved away from the stomach and to areas where it might be used to run or fight, such as the legs or arms. Less activity in the abdominal region and an increase in adrenaline are some of the many causes to losing your appetite. TLDR- Your body is allocating bodily resources effectively for a threat it perceives to be real and life threatening, but is really just mental anguish that it cannot differentiate.", "To tag on to OP's question, why do some of us do the opposite and stress eat?", "To go along with other answer, your gut can also sometimes induce vomiting if you are under very heavy stress In order to free up even more resources for the fight or flight response. The sympathetic nervous system, I believe, is responsible for increased heart rate, faster breathing, and tightness in the gut in order to prepare you to respond to threats. Even though it may just be as simple as a math test. Our body releases the same stress hormone so we have the same reaction. Even though the stress we feel today is mostly social anxiety stress or such, we still react as though we are physically in danger and food can wait to digest later. Surviving now is more important than getting a bite to eat to our brain. Edit: changed reaxy to react. What the hell autocorrect", "The exact response is determined by the type of anxiety or stress you\u2019re feeling. Long term stress such as a final coming up/big event you have to get ready for are handled by the internal medulla of the kidney. This area produces a \u201ccompliment\u201d to adrenaline called cortisol. Cortisol causes you to have a large craving for fats and carbs so that your body has energy reserves for when the big event occurs. It expects you to be in a big fight or have to run far, so it can turn the fat stores into energy. Thats why stress eating is such a problem. It\u2019s natural and can\u2019t truly be fixed The external kidney, the adrenal gland, produces adrenaline. Adrenaline acts to stim blood flow away from non-essential parts of your body to your lungs and heart so you can do things faster (important to note NOT LONGER). It primarily pulls it away from the gastro-intestinal region, the extremities, etc. This is why great cold medicine uses pseudoephedrine. This copy of adrenaline is made as an extended release to open airways so you can get more oxygen and counter that stuff nose", "Anxiety is fun: The liver releases sugars and fats which flow into the blood stream to provide energy. Breathing becomes faster, providing more oxygen. Heart beats faster and blood pressure rises to make sure blood reaches the areas needed. Blood clotting mechanisms are activated in case of injury and bleeding. Muscles tighten, ready to run or fight. Saliva dries up and digestion stops so that more blood can be diverted to the muscles. Sweating increases to cool the body. Bowel and bladder muscles may become loose. Pupils in the eyes widen to let in more light and help clearer vision. All senses are heightened. Brain thinks of other things that could be a threat. Blood supply is diverted from the skin to reduce bleeding if injured.", "for questions like this I find its always very helpful to adopt a \"primitive\" mindset. by this I mean lets think about this if we were living in caves in the year 10000BC what would make us nervous/anxious back then? a predator coming to eat us. under these conditions would it be useful to be distracted by a nagging sense of hunger? Nope. to effect the necessary changes we have the Sympathetic and Parasympathetic nervous system. Simply put; just equate sympathetic to \"fight or flight\" and parasympathetic to \"rest and digest\".", "Your brain is so focused on whatever is going on in your head that it forgets about your stomach. Basically it's saying \"I'm hungry but I'll worry about that later because this shit's more important.\"", "The stomach and intestines don\u2019t need much blood when you\u2019re ready to run. If they ain\u2019t got blood they don\u2019t need food.", "Same reason you might have to poop when you're nervous. It's part of the fight or flight response. Your body might need to move, FAST - less weight can make that happen.", "Also neurotransmitters which ordinarily are sympathetic, (speed up/stimulate) others area of the body such as the heart and noradrenaline, have a parasympathetic effect on the stomach and digestive organs! Slows down digestive tract and gastrin release when released!", "To add to what everyone has been saying about fight or flight, I'll add a little bit of Neuroscience. Your stomach has a lot of neurons in it, therefore there's a lot of neurotransmitter action happening there. This is where our \"gut feeling\" comes from. When it comes to fight or flight, you're dealing with the transmitters epinephrine (adrenaline) and norepinephrine (noradrenaline). Norepinephrine acts first. It's function is to get the body ready for action. Specifically, in the digestive tract, it activates this thing called gastrointestinal motility, which, for the digestice tract, is the ability to move food down the tract. To recap, fight or flight is triggered then a transmitter called norepinephrine inhibits the digestion process and it can do this because the stomach has a lot of neurons. Okay, now why does this need to happen? Yes, part of it is that you have better shit to worry about in the moment but that just doesnt have to do with the presence of danger. Part of it is to counter the negative effects of adrenaline. Adrenaline is the thing that gives you an increased heart rate and a higher blood pressure when you are in a fight or flight situation (also helped by noradrenaline which releases glucose in your body) and when it's released, it increases stress and gives anxiety and in the stomach, it makes it rumbly. Noradrenaline comes in and controls this effect, which ends up as you not feeling hungry! Tada! Sources: a few psych/neuroscience classes and I have adrenal issues.", "Follow up question: Why do I eat my weight in Doritos when I'm nervous?", "A bookend question, why after your nerves calm do you have a sudden urge to poop?", "When you're scared your body thinks you are in imminent, physical danger If you're in danger of death, you really don't need to digest any food inside of you, you have more important things to worry about Part of your body's response is to take blood away from your stomach and to the muscles in your arms and legs, since you will need to either run or fight", "here is a physiological explanation for this. When your are frightened, anxious or nervous, your body increases the activity of the sympathetic nervous system. This makes your body ready to run if there were some sort of danger. Sympathetic activity includes - Increased heart rate and increased heart contractility to increase the amount of blood reaching your muscles - Increased blood shunting (taking blood away) from non important parts of the body in times of danger (such as the stomach, intestines, prefrontal cortex, kidneys etc) -Increased blood flow to the muscles and heart to react Anxiety is the result of chronic activation of this system which explains the seemingly permanent loss of appetite."], "text_urls": [[], [], [], [], [], [], [], [], [], [], [], [], [], [], []], "score": [5800, 491, 180, 50, 28, 15, 7, 6, 5, 5, 4, 3, 3, 3, 3]}}, {"q_id": "7cvd2h", "category": "Repost", "title": "Why does moss/algae podaminantly grow on the north side of trees, houses etc.", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dpswj1j"], "text": ["The sun rises in the east and sets in the West and Generally in the northern hemisphere the Sun comes out of the South so the north side of buildings, trees, etc. Is the only side that doesn't receive direct sunlight and is thus the most likely to grow moss. The lack of direct sunlight results in dew, rain etc drying up the slowest on this side letting the moss grow."], "text_urls": [[]], "score": [3]}}, {"q_id": "7cz2j0", "category": "Repost", "title": "- In moments of intense concentration... why do we poke our tongues out?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dptru3g"], "text": ["When we focus on precise tasks, ideally you'd want to devote 'everything you've got' to finishing or performing them. Take painting for example, most of your focus is directed towards your hands and arms (Motor skills). Your body is always gathering information and reconstructing how, for example, the surface of a table feels, how cold or hot things are, and if you're upside down or right side up. A very important receptor is your *tongue*, which is one of the most densely populated bundles of receptors you've got. from a young age, you might have done this unconsciously yourself when focusing on a difficult or precise task. Essentially your tongue pokes out to prevent the sensations, tastes, and general feelings your tongue will send to your brain and disrupt your focus on other parts of the body. TLDR- In an effort to keep focus on a task, your body will unconsciously suspend some more prominent motor skills and sensations (In this example, the tongue) to prevent external stimuli from interfering with whatever you're currently focused on."], "text_urls": [[]], "score": [3]}}, {"q_id": "7cz6lw", "category": "Repost", "title": "Why are scientists looking for water on other planets? It may be necessary for life here, but what makes us think other species need it too?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dptrs5g", "dpts72r"], "text": ["We know what life looks like that requires water. We know the signs, we know it is possible, and it is something we can look for at a distance. Could there be an alien species out there that views water as acid and ammonia as clean air? Sure. But we have no idea if life can do that, and we have no idea what to look for if it does. So we go with what we know, at least until making planetfall onto distance planets is an option.", "Currently Earth is the only reference for life we have, so our current searches for life are based on it."], "text_urls": [[], []], "score": [5, 3]}}, {"q_id": "7d19n6", "category": "Repost", "title": "Why does hitting your shin on something like a scooter or shopping cart hurt so much and for such a long time?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dpu9exd"], "text": ["Probably because it's a more direct hit on your bones. There's no (or very little) muscle there to absorb the hit."], "text_urls": [[]], "score": [4]}}, {"q_id": "7d2qgd", "category": "Repost", "title": "What causes the tingling sensation known as 'pins and needles'? I know that it is a lack of blood flow in a part of the body, but why does that make it tingle?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dpulaoe"], "text": ["Contrary to popular belief, the pins and needles feeling isn't due to lack of blood flow to a body part. If that were true, my leg would have probably died due to lack of oxygen on the bus ride home. It's actually due to the fact that once you put pressure on a part of your body, you can actually cut off communication to that part from the point of pressure onwards. The pressure squeezes your nerve pathways so that they can't transmit sensations or receive orders from the brain as well as it should be. It's why your foot goes numb if you sit with one of your legs crossed, or if you're on a long cramped bus ride. Pins and needles occur after this connection with the brain is back to normal. It takes a while for your leg or whatever to get back in the full swing of things, and the pins and needles are just the sensations of that body part's nerves adjusting to the stronger connection it's getting."], "text_urls": [[]], "score": [8]}}, {"q_id": "7d2s8o", "category": "Repost", "title": "What causes the feeling of D\u00e9j\u00e0-Vu?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dpupg08", "dpuppi3"], "text": ["Sometimes something *really has* happened before. Like this question! :-) 1. [ELI5: What happens when we experience d\u00e9j\u00e0 vu? ]( URL_6 ) 1. [ELI5: Why do I sometimes experience D\u00e9j\u00e0 Vu? ]( URL_4 ) 1. [ELI5: What is deja vu and how does it work? ]( URL_5 ) 1. [ELI5: Why do we sometimes feel D\u00e9j\u00e0 Vu's ]( URL_2 ) 1. [ELI5: How exactly does Deja Vu happen, and is it abnormal to experience it daily? ]( URL_7 ) 1. [ELI5:Why do We Have Deja-Vu In Different amounts of Severeness? ]( URL_8 ) 1. [ELI5: D\u00e9j\u00e0 vu ]( URL_3 ) 1. [ELI5: Why do people have Deja vu for things that clearly never happened? In other words, what happens in your brain when you experience deja vu? ]( URL_1 ) 1. [ELI5: Deja Vu. Why does it happen and How? ]( URL_0 )", "Another analogy is that you brain sends a message to your \u2018memory bank\u2019 & then waits for the memory bank to confirm it has received it. Sometimes there is a delay in the memory bank sending the confirmation it has received the message, so the brain sends the message again & the memory bank gets double stimulation. It\u2019s the confirmation from the second lot of stimulation that gives us the feeling of \u2018I\u2019ve seen this before.....\u2019 Yes. Less than a millisecond ago, but because it didn\u2019t get confirmed as stored the first time, you can\u2019t remember where you\u2019ve seen it"], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/1tljgo/eli5_deja_vu_why_does_it_happen_and_how/", "https://www.reddit.com/r/explainlikeimfive/comments/2zyk7o/eli5_why_do_people_have_deja_vu_for_things_that/", "https://www.reddit.com/r/explainlikeimfive/comments/3gupq1/eli5_why_do_we_sometimes_feel_d%C3%A9j%C3%A0_vus/", "https://www.reddit.com/r/explainlikeimfive/comments/1jnspm/eli5_d%C3%A9j%C3%A0_vu/", "https://www.reddit.com/r/explainlikeimfive/comments/1mwes3/eli5_why_do_i_sometimes_experience_d%C3%A9j%C3%A0_vu/", "https://www.reddit.com/r/explainlikeimfive/comments/12saub/eli5_what_is_deja_vu_and_how_does_it_work/", "https://www.reddit.com/r/explainlikeimfive/comments/512esi/eli5_what_happens_when_we_experience_d%C3%A9j%C3%A0_vu/", "https://www.reddit.com/r/explainlikeimfive/comments/2ts9ge/eli5_how_exactly_does_deja_vu_happen_and_is_it/", "https://www.reddit.com/r/explainlikeimfive/comments/59xxeq/eli5why_do_we_have_dejavu_in_different_amounts_of/"], []], "score": [6, 3]}}, {"q_id": "7d4h83", "category": "Repost", "title": "How does a mental condition like stress or depression take a physical toll on ones body?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dpuza40"], "text": ["Think of your body as a regular starship. Usually the crew goes on with its regular duties, on regular schedule and work efficiently. A lot of the stuff is boring stuff like routine maintenance, cleaning the ships, preparing meals etc. Then an alarm goes off. \"Under attack by Klingons!\" The crew now goes on high alert. The phasers are ready to be fired on command. The shields can be deployed in a split second. All life-support systems are checked to ensure that nothing goes wrong. But this comes at a price. They are now working on shorter sleep. All non-essential tasks get cut back. Trash accumulates, the meals served get simpler, regular maintenance is postponed. This lasts as long as the alert is on. But the alert never goes off, even when there is no threat. All that lack of maintenance comes back and things start breaking over time. Garbage accumulates. The crew makes mistakes due to lack of sleep. Stress is like a state of constant alert. In the short term, the body is able to do stuff it could not normally do. Pull an all-nighter for that exam- pfft. In the long run, everything that the body has been postponing addressing comes back to bite you, and the body suffers as a result."], "text_urls": [[]], "score": [4]}}, {"q_id": "7d5l3g", "category": "Repost", "title": "Why do men go bald but most women don\u2019t?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dpv7nub"], "text": ["**Dihydrotestosterone (DHT).** It's a more potent cousin of normal testosterone. It's a super hormone of sorts! And it has profound impact on the men. From the development of genitals to pubic/body hair to maintenance of prostate, etc. Sadly, as a side effect, it also causes pattern hair loss typically associated with men. Some men's hair follicles are more sensitive to it than others'. Some produce more DHT than others. And typically those people have higher likelihood to become bald. Women don't need DHT as much as men do. So, they produce far less. So, DHT is not the leading factor for their hair fall."], "text_urls": [[]], "score": [3]}}, {"q_id": "7d8x4p", "category": "Repost", "title": "How exactly does lobotomy work and how does it affect the person after the procedure?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dpvxv19"], "text": ["Depends on what kind is performed. The \"ice pick\" one we've all heard of is very rudimentary and accesses the frontal lobe through the eye socket. It attempts to \"helpfully\" damage the frontal lobe to theoretically calm people with violent or volotile emotions. Mostly it just leaves them catatonic. Edit: I recently learned this from the book \"brain on fire\" about the author who struggled with encephalitis"], "text_urls": [[]], "score": [3]}}, {"q_id": "7dbun3", "category": "Repost", "title": "Why does social media sites like Facebook want you to use their app instead of the mobile website?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dpwjtzc"], "text": ["If you download and install their app they have a lot more data on you. If the service is free the product is you."], "text_urls": [[]], "score": [6]}}, {"q_id": "7dcxmj", "category": "Repost", "title": "Why does an object traveling at the speed of light gain infinite mass", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dpwrzue"], "text": ["Relativistic mass is an outdated concept. Many contemporary authors such as Taylor and Wheeler strongly argue against the concept of dynamic mass, and most modern textbooks actually avoid it. Taylor and Wheeler state [1] > The concept of \"relativistic mass\" is subject to misunderstanding. That's why we don't use it. First, it applies the name mass - belonging to the magnitude of a 4-vector - to a very different concept, the time component of a 4-vector. Second, it makes increase of energy of an object with velocity or momentum appear to be connected with some change in internal structure of the object. In reality, the increase of energy with velocity originates not in the object but in the geometric properties of spacetime itself. It is a lot more more useful to simply stick to rest mass and consider the increase in kinetic energy of a fast moving object. [1] E. F. Taylor, J. A. Wheeler (1992), Spacetime Physics"], "text_urls": [[]], "score": [5]}}, {"q_id": "7dhq8o", "category": "Repost", "title": "why some people pass out when they see blood?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dpxvxuw"], "text": ["This is caused by the vasovagal reflex/reaction/response. It's the same thing that can make you pass out from severe pain, fear, or being stuck in a stuffy, hot room. Normally this reflex helps maintain your blood pressure, but when it's triggered by emotional reactions it can \"run away\" without control. Super simply put, it's dropping your blood pressure until you pass out. Some people have a really strong fear of blood due to past experiences and/or lack of normal exposure to blood -- enough so to trigger this response uncontrollably."], "text_urls": [[]], "score": [4]}}, {"q_id": "7eg9ra", "category": "Repost", "title": "How can almost every country in the world be in debt? Can't some of the debt cancel out?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dq4utkg", "dq4t0h0", "dq53i4k", "dq4xrtc", "dq50jxf"], "text": ["Countries borrow money from other countries **and** individuals. You can buy a bond from your country - meaning your country owes you money.", "Alice borrows $1 from Bob. Bob borrows $1 from Claire. Claire borrows $1 from Alice. Everyone is in debt. If there is interest on the loans, then everyone owes more than they are owed.", "It does cancel out. I think the word you mean is **deficit** not **debt**. I owe my brother Rick $20 for beers last night, which I'll pay him later. I also have some cash in the bank. I have a *debt*, but in total I have more money than I owe. I have a *surplus*. ... My friend Kevin owes $10k to the student loan company which he pays every month, but he only has $5k in the bank. Kevin has a *debt* that is more one than he has. Kevin has a *deficit*. ... My parents owe nothing and they own a house. They have *no debt*. They have more money than they owe. My parents have a *surplus*. ... Just because a country (or person) has a debt does not mean it [has a deficit]( URL_0 ).", "Debt is simply money owed at a certain time. Countries issue bonds or make other agreements to pay others at a later date, so now they are in debt. They can\u2019t pay it all off because right now isn\u2019t the time all that money is due.", "The money that is owed by governments is not necessarily owed to other governments. It is owed to all kinds of people--individuals, companies, and organizations that might be anywhere in the world. If you own a government bond, then part of that debt is owed to you."], "text_urls": [[], [], ["https://en.wikipedia.org/wiki/List_of_countries_by_current_account_balance"], [], []], "score": [22, 13, 5, 3, 3]}}, {"q_id": "7ep8nm", "category": "Repost", "title": "How do ISPs work? Where do they get their internet?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dq6kjnj"], "text": ["Think of it this way. The internet is like a postal network. The ISPs are the postal service. They coordinate all of the packages and make sure that they arrive at the right place, on time. The ISPs can also expand the road network to reach more customers. They can also widen existing roads so that more traffic can be handled. All of the different ISPs around the world work together just like most postal services around the world."], "text_urls": [[]], "score": [6]}}, {"q_id": "7f1xbh", "category": "Repost", "title": "Shaken not stirred", "title_urls": {"url": []}, "selftext": "Can anyone explain why or what would be the difference between a shaken drink or a stirred one.", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dq8w9b8", "dq8y1s1"], "text": ["For drinks it's much more \"high class\" to have it stirred and not shaken as many think it dilutes the ice more if it's shaken... That's why it was always odd when James bond would say shaken on stirred... But honestly I've never tasted a difference between the two... It's just a weird thing like pinkies out and stuff like that", "When you shake it, the ice breaks a little, melting faster, watering down the martini. Stirred could be seen as the more pretentious, upper class way of drinking it, and it could be part of James' desire to rebel against the posh world he finds himself in by having the more down to earth, \"rough and ready\" version of the drink. However, I do believe in the books he asks for it stirred, not shaken, but when making the first movie they decided it sounded better the other way around."], "text_urls": [[], []], "score": [4, 4]}}, {"q_id": "7f35f9", "category": "Repost", "title": "Why do you have to salt pasta water? Why isn't the pasta already salted?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dq966fd"], "text": ["There are a few reasons not to add salt to the pasta dough itself. The most important that I know of is that adding salt to the dough slows down gluten production. Since pasta dough tends to be made quite quickly (unlike bread dough which is given time to rise) the addition of salt at the dough stage would result in a sloppy dough. It's easier form a manufacturing standpoint to leave the salt out at this stage and compensate later. A second reason is that pasta dough is usually made with only flour and egg - no water. Thus, there is little material for the salt to dissolve in and one tends to end up with grains of salt present in the dough. This provides an unappealing texture as well as potentially uneven flavor to the pasta. Perhaps this can be circumvented somewhat by pre-dissolving the salt in the egg mixture. Thirdly, it is good from a manufacturer's point of view to allow the consumer to season the pasta to their desired level of saltiness, both for health reasons and personal flavor preference. It also allows them to get a lower sodium measurement on the packaging."], "text_urls": [[]], "score": [21]}}, {"q_id": "7f4ii7", "category": "Repost", "title": "What exactly are the economic benefits behind Black Friday for companies and consumers?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dq9jmyq", "dq9fh8p", "dq9jnsa"], "text": ["They\u2019re goal is to get you in the store with the promise of a $150 50 inch 4K tv ( which they only have about 7 of) so you can then spend money on other things at the store.", "They don't actually make a whole lot of money it's all about sales numbers, it actually cost him quite a bit in margins at the store level. But the idea is that you win the consumer over for the holidays so they spend the rest of their money there that you have marked up.", "Many manufacturers have left over inventory and want to move all this product. Others just want you in the store, because you might buy other stuff (not on sale). There are tons of reasons to mark stuff down around the holidays, and black Friday grew into it's own holiday as a full day for shopping is good for all retailers."], "text_urls": [[], [], []], "score": [5, 5, 3]}}, {"q_id": "7fb2op", "category": "Repost", "title": "How do cellphones know what signal from what network to listen to? What is different about different networks' cell towers that a phone can decipher which one to listen to?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dqamlpl"], "text": ["Your cell phone is basically a very fancy radio. For it to communicate with the tower it needs to know what frequencies to broadcast on. It has a SIM card that tells it what network you're subscribed to and which frequencies to broadcast over and receive."], "text_urls": [[]], "score": [6]}}, {"q_id": "7fdex8", "category": "Repost", "title": "why didn't medevil paintings have any perspective?", "title_urls": {"url": []}, "selftext": "For example: [No perspective]( URL_2 ) [Nearly flat]( URL_0 ) [An attempt at creating perspective but it comes off as almost abstract]( URL_1 ) [Looks like they were going for realism, but still that darn perspective]( URL_3 ) Now I'm not bashing medieval artists (and I'm not a history buff so I could be pulling some of these from different points in time, I just hope they're all before the rennaisiance) but it strikes me as a bit odd that these people, who were in the profession of making art and probably had been for most of their lives, were leaving out such an important detail like figures getting smaller the further away they were. Maybe it was just the style at the time, maybe they were just designed to be easy to read on a mural as a story, maybe without glasses to enhance vision it didn't really matter if there wasn't a certain degree of detail, whichever way I've always wondered this, and the fact that as you go further back in time, you seem to get less and less perspective (think Egyptian art) Can anyone tell me if there are any theories or anything explaining this?", "selftext_urls": {"url": ["https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcTWPXJfwjx1qCvWlylo-lHJWfeKcX5az4R6Dtg1M2OcsbXZYU95CA", "http://cdn-2.medievalchronicles.com/wp-content/uploads/2015/06/Famous-Medieval-Painting-Duccio-last-supper.jpg?e2299c", "https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcTs_JOTidK0pU03eWxP_CBg9JncR6iO7jtofWDzdYIqmtWiNbgtiQ", "https://www.metmuseum.org/toah/images/h5/h5_37.80.4.jpg"]}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dqb3uu0", "dqb4175", "dqbsq3h"], "text": ["Artists had not developed the technique of perspective until the beginning of the 15th century with Italian architect and artist Fillipo Brunelleschi. Medieval paintings don\u2019t have perspective because it was not a \u201cthing\u201d yet. A lot of artists attempted to create it but didn\u2019t really understand how to. Brunelleschi was the first to figure out linear perspective, or making two lines converge to make them appear to look more distant. Other artists then caught on, mimicking the technique.", "> it strikes me as a bit odd that these people, who were in the profession of making art and probably had been for most of their lives, were leaving out such an important detail like figures getting smaller the further away they were. It is a one-two punch of being ignorant of the technique and not desiring to learn it, as the focus of the art wasn't the accurate reproduction of the scene or the human form but rather the spiritual or symbolic meaning behind the image. Baby Jesus for example didn't look like a real human child, but it may have been considered a virtue that he didn't appear as such because he was supposed to be different. There is also the matter of what defines \"good art\" in the view of the time. Was it perspective and proportion, or subtle shading and composition to draw the eye? Is symbolism or making sure the top of the table is parallel to the ground more important? The focus and meaning of art was different during that time which yielded images that may not be seen as good today.", "I'm not an art historian but I did take an art history course which explained one reason why it was hard for artists to nail perspective. Before the invention of oil paints, most paintings were frescos. A fresco is color applied to a wet plaster wall or ceiling. Once the plaster dries, the work cannot be altered and the plaster dries quickly. Therefore the painting must be done rapidly, without too much attention paid to details like perspective. Another drawback to a fresco is that it must be done on the wall, which - depending on the wall - may limit the use of live subjects. This may mean the artist has to rely on memory or sketches of the scene. Paper wasn't even available until 1100 and was quite expensive once it did become available, so most preparatory drawings were done on wood, slate, or wax. These preparatory drawings tended to be reused by an artist for multiple paintings since they were difficult to produce. The advent and wide adoption of oil paint in the 15th century fixed these two problems. Oil painting allowed artists to work slowly and granted them the freedom to use canvas which is comparatively mobile. This meant they could actually be at a scene they were trying to illustrate and could take days or weeks to work instead of hours, so their subjects could really be studied and their paintings could be perfected. Also, by 1500, paper and graphite were widely available and sketching began to be considered a serious art. This probably also had some impact on artists as they refined their sketching skills which no doubt translates to better painting skills. Edit: I forgot to mention that with a fresco you cannot even fix a mistake by applying a second color over the first color. With oils, you can wait for the first color to dry and apply a new layer of paint. This plus the ability to work slow dramatically changed how painters worked."], "text_urls": [[], [], []], "score": [19, 4, 3]}}, {"q_id": "7fk0zl", "category": "Repost", "title": "How are mountain goats so nimble and sure footed?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dqchetp", "dqce5t7", "dqcmysh"], "text": ["Part of the success of mountain goats is the design of their hoof. Think of them like a set of hands that are able to grab onto the mountain. They are less standing on the side of the mountain and more grabbing the side of the mountain. That said sometimes mistakes happen, and those mistakes help to guide the next generation.", "Because the ones that aren't went **splat** on the side of a mountain and didn't get to make babies. The ones that survived had the best sense of balance, the best feet, and the best instincts for surviving.", "Mountain goats have a rather bizarre foot structure, where they essentially balancing on thier toes and have a fatty cushion for their heel. They can also control their hoof split. Imagine a ballet dancer with no discomfort who can also wrap her toes around things. I've climbed fifty feet up a sheer rock face only to have one of these bastards run straight up to say hello. They can hug crimps that we can barely see. On top of that, they have a severe lack of the fear of heights. But they aren't perfect. Recently in my local news a goat jumped off a cliff and landed on a car. As they age, their weaknesses kill them. The ones with better balance and eyesight live much longer and have more offspring. They are built like linebackers. They have extreme control, and that helps them evade predators and reach food. Tl;dr study bodies, nimble feet."], "text_urls": [[], [], []], "score": [7, 6, 3]}}, {"q_id": "7fmt1c", "category": "Repost", "title": "Why do Tupperware (and some other plastics) get white spots after being washed in washing machine?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dqcwntf", "dqd3ca4"], "text": ["The dishwasher (and microwave) can get too hot, melting the plastic, which causes this. To prevent, hand wash and don\u2019t use in the microwave.", "Everyone else is wrong. White spots on Tupperware are hard water deposits. Good luck preventing them, they are harmless though."], "text_urls": [[], []], "score": [199, 3]}}, {"q_id": "7fn3t4", "category": "Repost", "title": "Why are credit cards used so much these days and what are the benefits of it over a debit card?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dqcyup2", "dqcy6w4", "dqczcri"], "text": ["A lot of people seem to be giving you the same bad information you've likely already heard. Credit cards don't inherently equal debt, they are tools. Different cards are intended for different uses. Many people think of credit cards as a way to buy now, and pay over time. While you certainly can do that, you really shouldn't in most cases. There are two types of credit card users. Revolvers, and transactors. Revolvers spend money, and carry a balance, paying interest over time. This type of credit card use should be avoided except in circumstances where you may have no other choice. Transactors use credit cards for their normal spending, and pay them off in full every month. Many people aren't even aware of the fact that if you pay your statement balance in full every month, you don't pay any interest. Credit cards have 4 primary advantages: Rewards- Typically in the form of cash back, or travel points etc. Security- If your card is ever compromised, it's much easier to deal with the claim on credit than it is on debit. Benefits- Credit card companies also offer you some purchase benefits, such as extended warranties, free insurance in rental cars, matching sales prices after purchase, ticket concierge services, and more. Flexibility- Being able to purchase the things you need, and pay bills when they're due, and knowing you'll have a single payment on the same day every month makes it much easier to budget. It can help avoid a paycheck to paycheck lifestyle. It requires discipline to use credit cards and not accumulate debt, but the advantages are well worth it for those who can use them properly.", "A credit card provides protections that you don't have with a debit card. For example, if your credit card is compromised, you simply dispute the charges, you are not actually out any real money. If your debit card is compromised the fraudulent charges aren't just on paper, the money is actually taken out of your account, so you then have to go through the whole dispute process to get your money back. In the meantime your account is locked and you have no access to your money, if there is any left.", "* It's easier than carrying cash * It's _way_ easier than paying with a check * It's an easy way to track how much you're spending and where * As long as you pay off your balance in full each month, there's (generally) no additional cost * Having available credit in the form of a credit card boosts your credit score (provided you aren't carrying a huge balance). Paying it off (or at least the minimum payment) consistently each month builds a good credit history. Both are good things to have. * Credit cards often offer rewards, in the form of airline miles, points, cash back, etc. * Lesser known benefit: purchase protection/warranty extension. Credit card companies will often cover purchases for a limited time after the manufacturers warranty expires. I was able to get a tablet computer replaced 14 months after I bought it because I bought it on a credit card. As far as benefits over debit cards, as other people have eluded to the risk is higher with a debit card. If someone charges $1000 to your credit card, you have a $1000 charge on your card until your card issuer reverses it. If someone withdraws $1000 from your bank account, that money is gone until the bank replaces it. That means checks may start bouncing, you can't withdraw money, etc. Huge hassle. There are benefits to debit cards, however: * Using them (or misusing them) won't affect your credit score. It will affect your bank account, however. * Prices using debit cards can (sometimes) be lower. Swipe fees charged by banks to merchants are generally lower for debit. That savings is sometimes passed on to you. * If you can get a bank account, you can get a debit card. If you have bad or no credit, getting a credit card can be difficult: you may end up with higher fees, a lower credit limit, or you may be outright rejected. Tl;dr: Easier, less liability, more rewards. Just be smart about it."], "text_urls": [[], [], []], "score": [140, 13, 7]}}, {"q_id": "7frj2o", "category": "Repost", "title": "How can a piece of paper folded 103 times be larger than the observable universe?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dqdw00b", "dqe1hxx", "dqdvvbb", "dqdwacq", "dqebsck", "dqebkx0"], "text": ["Exponential growth. Each fold doubles the thickness of the paper. If I gave you 1 penny today, and promised to give you twice as much money tomorrow, and twice as much the day after, and so on and so on, on day 30 I'm giving you over $5 million dollars. You can do the math on this yourself pretty easily though. Open the calculator on your computer, and type in 0.0039 (the thickness of a piece of paper). Press the Times button, and then the number 2, and press enter. Now press enter 102 more times. By the mid-50's your calculator will actually reach a point where it has to start using exponents, and by 60 you'll have surpassed the what the calculator is capable of.", "And not to be pedantic, but wouldn't the stack of folded paper be *thicker* than the diameter of the observable universe, but it's *width* would be 1/2^103 times the size of the original width dimension, and it's length unchanged? The point being the *folded paper* won't be bigger than the observable universe; only one of it's principal dimensions (thickness).", "When you fold something once, you make it 2x as thick. Fold it again, you make it 4x as thick. Fold it N times, you make it 2^N times as thick. 2^103 is a very, very, very large number. (Approximately 1 followed by 31 zeros.) So even if you are folding something very thin, if you were able to fold it that many times, it would become 10^31 times thicker.", "It's math. Theoretical in that I think 10 times is about the most that's ever been achieved. More interesting to me has always been how big a piece of paper would have to be to start with, assuming it possible to be in a position to fold it 103 times. That's even simpler math but I've never gotten around to it.", "As others have pointed, it's not physically possible. If it were, the surface area of the paper would also shrink by a factor of 2 each time. So you'd end up with more like one very, very, very thin rod that's longer than the observable universe. The long and short of it is, exponential growth is *very* fast. The difference between a single byte and a kibibyte is just 10 powers of 2. Same with going up to a mebibyte, gibibyte, tebibyte.. That's still \"only\" 40 powers of 2.", "It's not so much an arbitrary number of folds, as it is an exponential increase in thickness. Imagine it took X folds of a single sheet to be taller than the empire state building. At X-1 (one away) it would only be half as tall. At X-2 it would only be 1/4 as tall. Another way to think about it is each fold doubles the height, thus the 20th fold creates the same increase in size as all of the 19 folds that came before, and the 100th fold creates the same increase as all the 99 folds before it. What is interesting is when it comes to the maximum size something can be, and the minimum size, our existence is quite a bit closer to the maximum, than the minimum. Like if you changed your size by a factor of 10, you could do this farm more times getting smaller, than you could getting larger."], "text_urls": [[], [], [], [], [], []], "score": [949, 73, 30, 10, 8, 5]}}, {"q_id": "7frqkg", "category": "Repost", "title": "Holding onto nothing but paint, how can a praying mantis stay on the roof of a car traveling 60 mph and not get blown away?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dqdysbn"], "text": ["The micro surface of the paint, and the mantid\u2019s legs, are both rough. Think like the legs of a hiking boot dug into rocky ground as you face the gale."], "text_urls": [[]], "score": [4]}}, {"q_id": "7fv07s", "category": "Repost", "title": "how does one alphabetize kanji?", "title_urls": {"url": []}, "selftext": "English for example has 26 letters in defined order and words or names can be sorted easily this way, for example, making directory for business employee or phone book, or dictionary for words. But in Asian countries like Japan, their name aren't spelled in letters but in kanji and there can be several thousand different symbols for words or names. How would a school sort student's name? Or how would a typical Japanese dictionary be sorted so they can quickly look up word? Not just Japan, but many Asian countries (China, Korea, etc)", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dqekzyt", "dqek1pn", "dqeirns"], "text": ["Korean doesn't fall into this category: it actually uses a real alphabet. Those characters that look like complicated Chinese-style logograms are actually syllable blocks, made up of (usually) two or three letters that represent sounds, and these letters have a fixed order (however, North Korea and South Korea use different alphabetical orders). For example, the writing system is called \"\ud55c\uae00\". It's two syllables, and each syllable is read from left to right and from top to bottom. The individual letters are: * \u314e = h * \u314f = a * \u3134 = n * \u3131 = g * \u3161 = eu (sometimes transliterated \"\u016d\") * \u3139 = l -- so: \"hangeul\". No problem at all: \"\u314e\" is 19th in the South Korean alphabet. Chinese ideograms, or kanji in Japanese, are more complicated. They're sorted by radical and stroke count. The \"radical\" is the part of the character that gives you a clue about the meaning of a word. For example, the character \"\u5abd\" means \"mother\": the radical is on the left, \"\u5973\" and means \"woman\". The rest of the character, \"\u99ac\", gives a clue about the pronunciation. Its actual meaning is \"horse\", but in Mandarin Chinese it's pronounced \"m\u01ce\". This is *almost* the same as \"m\u0101\", the word for \"mother\", so the whole character means: \"This is a word for a woman, and it sounds a bit like the word for a horse.\" There are a bit more than 200 radicals in Chinese, and they're sorted according to the number of strokes you need to write them. [Here's a list of the 214 radicals encoded in Unicode]( URL_0 ) -- notice how they get more complex the further down the list you go. So most dictionaries are arranged such that you first look up the radical, and then you look for the character you're searching for, again according to the number of strokes. If you want to look up \"\u5abd\", for example, you need to first find \"\u5973\", which is the 38th radical. You'll have a long list of characters that use that radical, again sorted from least strokes to most strokes -- you know that \"\u5abd\", which needs 10 extra strokes, is going to be further down the list than \"\u5974\", which needs 2. [This is the list of characters that use the 38th radical]( URL_1 ) -- there are 681 in all.", "There are three different kinds of character systems in use in East Asian languages, ones that represent simple sounds (alphabets), ones that represent whole syllables (syllabaries), and ones that represent concepts (logographic systems). They're treated differently, and the same language sometimes uses multiple sorts (for instance, written Japanese uses both the logographic kanji and the syllabaries hiragana and katakana). Alphabets and syllabaries typically just have a canonical ordering of the characters, and they're sorted lexicographically in the usual way. Logographic writing systems are really what you're asking about, though, and those have a couple different ways. The most common is the radical-and-stroke system. Each character is classified into groups based on what the \"primary\" component (known as a radical) is, and those radicals are then ordered. Within a single radical, characters are sorted by the number of lines (known as strokes) used in the character, from least to most. Within a group of characters with the same primary radical and number of strokes, ties are broken relatively arbitrarily (usually there's a convention for this). Another way is to sort them based on how they would be written in a different writing system that has a built-in sorting method. Some Japanese dictionaries and such are done this way, by sorting words based on how they'd be written in kana. Some languages that use CJK characters don't have such an option, though, since they don't have more than one writing system.", "Korea has an alphabet song, just like English. Their is an order is \uac00 \ub098 \ub2e4, etc. So, names are ordered by their \"alphabet\" first symbol."], "text_urls": [["https://en.wikipedia.org/wiki/Kangxi_radical#Unicode", "https://en.wikipedia.org/wiki/Radical_38"], [], []], "score": [16, 5, 3]}}, {"q_id": "7fw4gr", "category": "Repost", "title": "Why does hard physical activity sometimes cause you to throw-up?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dqesbhp"], "text": ["Basically, it's an evolved response. Intense exercise triggers the production of hormones like adrenaline. These hormones divert blood from the digestive system and to you muscles in order to provide your muscles with the oxygen and nutrients needed to perform. The lack of blood flow to your digestive system causes digestive disfunction like nausea and diarrhea. In a world where we are fleeing from predators, every bit of energy is needed to survive. Temporarily halting normal digestion to provide extra energy to your muscles can be the difference between life and death. Additionally, dehydration and over hydration (hyponatremia), both common in exercising individuals, can cause nausea."], "text_urls": [[]], "score": [8]}}, {"q_id": "7fxzrg", "category": "Repost", "title": "Why do people get hiccups when they're drunk?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dqf91rx"], "text": ["Yo ho ho! Yer not alone in askin', and kind strangers have explained: 1. [ELI5: Why do people hiccup when they are drunk? ]( URL_8 ) 1. [ELI5: Why do you get hiccups when you drink too much? ]( URL_3 ) 1. [ELI5: why are people more likely to get the hiccups when they're drunk? ]( URL_4 ) 1. [Why is having the hiccups associated with being drunk in film and television? ]( URL_7 ) 1. [ELI5 why do intoxicated characters in old cartoons get the hick ups? ]( URL_2 ) 1. [ELI5: Cold weather alcohol = hiccups. Why? ]( URL_5 ) 1. [ELI5: Why do people get the hiccups when drinking? ]( URL_1 ) 1. [ELI5: Why does alcohol cause hiccups? ]( URL_6 ) 1. [ELI5:Why do people hiccup when they've been drinking alcohol? ]( URL_0 )"], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/1uxua8/eli5why_do_people_hiccup_when_theyve_been/", "https://www.reddit.com/r/explainlikeimfive/comments/5ejdsg/eli5_why_do_people_get_the_hiccups_when_drinking/", "https://www.reddit.com/r/explainlikeimfive/comments/34lp17/eli5_why_do_intoxicated_characters_in_old/", "https://www.reddit.com/r/explainlikeimfive/comments/1ie0nx/eli5_why_do_you_get_hiccups_when_you_drink_too/", "https://www.reddit.com/r/explainlikeimfive/comments/2mc2p5/eli5_why_are_people_more_likely_to_get_the/", "https://www.reddit.com/r/explainlikeimfive/comments/5j72co/eli5_cold_weather_alcohol_hiccups_why/", "https://www.reddit.com/r/explainlikeimfive/comments/4k2b8m/eli5_why_does_alcohol_cause_hiccups/", "https://www.reddit.com/r/NoStupidQuestions/comments/2s2kz5/why_is_having_the_hiccups_associated_with_being/", "https://www.reddit.com/r/explainlikeimfive/comments/367mlu/eli5_why_do_people_hiccup_when_they_are_drunk/"]], "score": [5]}}, {"q_id": "7fzkyr", "category": "Repost", "title": "Why do ice cubes in a drink not want to move no matter how much you rotate the cup?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dqfhzpc", "dqfxg7i"], "text": ["Friction and inertia. Ice floating in water has very little friction with glass. In fact, the water functions as a lubricant between the two. The ice has mass. Mass resist motion. By spinning the glass you are trying to move the ice by moving the water. Water doesn't have enough friction on its own to move the ice easily. Given enough time in one direction the ice will begin to spin. If you oscillate you cancel out all movement.", "When you rotate a glass you generally do this at low speeds. The ice cubes will not rotate because the only method to transfer momentum at these low speeds is through friction, specifically shear stress in the fluid. This can be attributed to the \"stickiness\" of the liquid, and can be visualized if add something like soap to water. You will see as you rotate the glass the fluid near the glass edge moves at approximately the same speed as its surface, but towards the center there is virtually no movement. You can solve this using polar-cylindrical coordinates of the Navier-Stokes equations. Now, if you put a spoon into the glass and spin it, youll find that the ice cubes move much more easily. This is because the spoon induces advection. Advection can be thought of as bulk motion of the fluid, for example large vorticies you see behind airplanes or the turbulence you observe when you jump into a pool. Advection is dissipated through shear stress, which is described above and why these large vorticies eventually \"disappear\". Essentially, motion that induces advection induces higher pressure gradients, which in turn induce a larger force on near by bodies. TLDR: turning the glass does not induce advection, it induces viscus motion which is only appreciable at small scales of motion."], "text_urls": [[], []], "score": [18, 3]}}, {"q_id": "7g50d0", "category": "Repost", "title": "Why do balloons make such a loud noise when they pop?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dqgkbt1", "dqgv4n0", "dqgvklu", "dqgsi16", "dqh22kt", "dqhd4og", "dqgsul4"], "text": ["A balloon is essentially a vessel of compressed air. When the balloon pops, all of the air inside is released instantly and forms a pressure wave as it disperses to return to atmospheric pressure. You perceive the pressure wave as a loud noise when it strikes your ear drum.", "Imagine you had a phone booth full of water somehow sitting on the surface of a calm lake, and suddenly its walls disappeared. The water would rush out of it and create a wave that shot out in all directions until the lake evened itself out again. This is similar to how all of the air squeezed up inside a balloon pushes out and creates a pressure wave that you can hear when it bursts and equalizes with the air around it. People are pointing out that the balloon pop itself isn't really all that loud, it's mostly the acoustics of the room around it. To understand this, imagine you have the same phone booth sitting at the middle of a circular swimming pool. When the water rushes out, the resulting wave will bounce off of the outer edge of the pool and rush back inwards. It can then combine with itself and cause even bigger waves! Where the water in the lake will soon just have a small wave spread over a large area, the pool water will still have really big waves for a while after as they bounce around and interact with each other. If you pop a balloon in an 'anechoic chamber' (basically like a pool whose walls absorb waves completely and don't let them bounce back) then you'll only hear that first smallish wave of pressure.", "But bubbles don't make a loud sound when they pop?", "Most of the answers I'm seeing are missing a key point. It's the tension. Here's a fun trick. Tape a section then stab the taped area. Quietly deflates. Edit: fixed a typo Edit again! Seems to be a lot of people under the impression I'm saying it isn't the pressure - it is. The point I'm making is that the tension is the root cause, it's why the pressure erupts. Without the tension, the pressure wouldn't erupt. Kind of like why plants are green - yes, it's because they reflect green light, but that only gives a small bit of the answer.", "This might get buried but I have a related ELI5 question: why do latex balloons break into a bunch of pieces when popped instead of just letting air out of the puncture wound like other materials?", "Here\u2019s an example of a large balloon popping in slow motion. Tearing rubber snaps instantly. The tear doesn\u2019t move through stable rubber, the moving rubber travels through the air faster than the speed of sound, creating anywhere from a very minor to a slightly bigger sonic boom. Video should start at 80 seconds in, slow motion is maybe 15 seconds later. URL_0", "It doesnt. A balloon pop is actually quiet! What makes it loud is reflections and reverberation from the surroundings. Dont believe me? URL_0"], "text_urls": [[], [], [], [], [], ["https://m.youtube.com/watch?v=KdtSN7Zl9WQ&amp;t=80"], ["https://www.youtube.com/watch?v=MyP7i1B_QNk"]], "score": [16456, 441, 315, 140, 12, 10, 8]}}, {"q_id": "7g5ex6", "category": "Repost", "title": "How does google search work so quickly when there are so many web pages to search through?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dqglxkb"], "text": ["Through the use of indexes. Just like a book might have an index of key words and what pages to find them; Google does the same thing electronically by creating an index of key words and what web pages to find them. It\u2019s just that Google\u2019s index is many orders of magnitude larger - which is made possible by computing power. The method in which Google creates its index and prioritizes which web pages (based on how often a key word shows up or how much traffic a site may get, etc.) is part of its \u2018secret sauce\u2019."], "text_urls": [[]], "score": [4]}}, {"q_id": "7g9p73", "category": "Repost", "title": "When documentaries are released that feature people doing highly illegal things (mainly drug selling/making), is there anything that prevents the police from obtaining their information from the journalists to arrest them?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dqhjxqr"], "text": ["I know of some cases of people being arrested as a result of investigative journalism. For example, the TV program *60 Minutes* once did a feature about a man whose profession was to alter the odometers on cars, so that the cars would appear to have been driven fewer miles than they actually had been (thus enhancing their re-sale value). After the feature aired, the man was arrested. He foolishly had not tried to hide his identity. If journalists agree to hide someone's identity, however, they will generally be very insistent upon doing so, and for a very practical reason. If you cannot trust journalists to keep identities hidden, then many people will no longer be willing to grant interviews to journalists. There are cases of journalists who were ordered by a judge to reveal an identity and still refused to do so, even though they went to prison as a result. Many people who are engaged in illegal activities do want to present their point of view to the public. Also note that laws can change. Look at all the jurisdictions in which recreational use of marijuana is now legal. So just because something is illegal, does not mean that you cannot argue in favor of it."], "text_urls": [[]], "score": [3]}}, {"q_id": "7gbn8r", "category": "Repost", "title": "Why does chewing mint gum make everything you drink feel like liquid nitrogen?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dqhxh5i", "dqi5c68", "dqi5p9r"], "text": ["Your mouth has receptors called TRPM8 that usually respond when there is low temperature in your mouth which tells your body \"Hey its cold!\". It does this by opening an ion channel and letting charged molecules flow through which creates an electric signal that goes your brain. Menthol or mint oil in mint gum can bind to these receptors, causing them to activate. This tells your brain \"Hey its cold!\" in your mouth when it really isn't. A similar mechanism exists for chillies, which is why they're \"Hot\". EDIT: Fixed name thanks /u/PM_ME_XBOX_MONEYCODE", "I like to take advantage of this phenomenon; I often have refrigerator-cold water waiting after brushing my teeth or eating a mint!", "It usually has nothing to do with the mint, most sugar free gum uses sugar alcohol (super sweet low calorie sweetener) to sweeten it. URL_0 \u201cIn addition to their sweetness, some sugar alcohols can produce a noticeable cooling sensation in the mouth when highly concentrated, for instance in sugar-free hard candy or chewing gum. This happens, for example, with the crystalline phase of sorbitol, erythritol, xylitol, mannitol, lactitol and maltitol. The cooling sensation is due to the dissolution of the sugar alcohol being an endothermic (heat-absorbing) reaction, one with a strong heat of solution.[11]\u201d"], "text_urls": [[], [], ["https://en.m.wikipedia.org/wiki/Sugar_alcohol"]], "score": [1429, 17, 6]}}, {"q_id": "7gcgxl", "category": "Repost", "title": "Why does microwaving food cause it to lose nutritional value compared to oven cooking?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dqi297q"], "text": ["Microwaves aren't magic. Food is not losing nutritional value by being microwaved - at least no more than if it were cooked in any other way. This is a myth."], "text_urls": [[]], "score": [7]}}, {"q_id": "7gfu88", "category": "Repost", "title": "why do French fries lose their crisp when microwaved?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dqiqtmu"], "text": ["Water in the potato turns to steam. Steam takes up much more space than the same number of particles of liquid water. So the pressure forces the steam out into the fried outer layer. When the outer layer cools, some of the steam condenses back to water."], "text_urls": [[]], "score": [3]}}, {"q_id": "7gg6cd", "category": "Repost", "title": "The Freemasons", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dqitd0b"], "text": ["If you ignore all the assassin's creed/conspiratorial thinking, the Freemasons are just a fraternal organization. They're selective about who they let in and it's a conduit for networking between fellow Masons, and an excuse to do secret rituals and be 'in the know' about things that random plebians don't. Basically the adult equivalent of the cool kid's club. I did go to dinner at a Masonic lodge once and the food was outstanding"], "text_urls": [[]], "score": [11]}}, {"q_id": "7gmyco", "category": "Repost", "title": "how batteries lose charge over time", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dqkso8f"], "text": ["First things first, you need to know how a battery works. Basically, two metals are submerged in an electrolyte solution, and separated from each other by something non-conductive. The electrolyte causes the metal to corrode, sort of how steel turns to rust. One wants to give off electrons in order to corrode, the other wants to take in electrons. Between the two, you can get a flow of electrons, which is electricity. Since they're separated by something non-conductive, they're only connected when you're using the battery. Like steel left in the rain, those metals are sitting in that electrolytic fluid. They naturally want to corrode. The process speeds up when you use the battery, but it's still happening when you're not. When charging a battery, you're basically reversing the process, using energy to break apart the corrosion on the metals so they can re-corrode when you need them to."], "text_urls": [[]], "score": [4]}}, {"q_id": "7gyxzd", "category": "Repost", "title": "What is a Boltzmann Brain and do humans and other intelligent, self-aware organisms count as one?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dqmxukl"], "text": ["Say you had a box of marbles, seperated half blue and half red down the middle. Now we shake the box, what will happen? It will become more disorganized, obviously. Red and blue marbles will mix up as you shake it. Eventually, it will reach the point where the are completely mixed up, in equilibrium. Shaking more won't make any further large scale changes. Your headphones in your pocket are the same deal. Put them in nice and organized, walk around a bit, and they come out a tangled mess. What I just described is the second law of thermodynamics. Entropy increases, things become more chaotic and disorganized over time. Now, this law is just statistical though. There's no reason why a bunch of mixed up marbles couldn't seperate themselves as you shake, or why you couldn't put your headphones in your pocket tangled and then take them out nice and coiled. It's just very unlikely. If you considered every possible setup of the marbles in the box, there's way, way more than are disorganized than there is seperated. If you considered your headphones, there's many more ways they can be tangled than they can be nice and coiled. Now, imagine instead of a box of marbles we have a universe full of atoms. Now consider this: A bunch of atoms grouped up nicely into a galaxy, a nice planet around a star with the perfect conditions, and a few carbons atoms randomly self replicating molecules, and this resulting in trillions of very complex brains of conscious humans and animals all in the same place at the same time. Now consider this alternative: a soup of particles just randomly all over the place in equilibrium. Small changes happen all the time, but overall the universe is just the shaken up box of marbles and it looks more or less the same everywhere. Nothing special, organized, or complex going on, just a nothingness of chaos. Which is more likely? Well, possibly the second. So why are well all here? Maybe we're not. Consider the marbles again. Them all sorting themselves back out through shaking is so unlikely it will never happen. But a small little pocket of red marbles could certainly group up, that's not as unlikely. Maybe somewhere out there in that soup of random gas in equilibrium floating through a universe of nothing, a random bit of gas spontaneously becomes slightly organized and fakes a single consciousness. A single consciousness not made of atoms on earth as we (believe) we are, but one with the fake memories of all of what we perceive as existance now. It's certainly could be more likely than 7 billion of then alive right now on the same rock. That consciousness is a Boltzmann brain, a spontaneous consciousness popping out of small localized bit or organization in a universe in equilibrium. It's kinda like the \"everything is all just one true person's dream, and none of this is real\" type of deal, but the dreamer is a bunch of red marble atoms that randomly got together in a fully shaken up universe and formed their brain. So no, people and animals as they appear aren't Boltzmann brains. As we observe ourselves, we don't exist in a state of equilibrium, a fully mixed up box of marbles. We exist in a slightly mixed up box of marbles, and we feed off the nature of the organization of the environment to keep oursleves alive. Alive being a highly organized state. And in the process make the universe around us more disorganized, life makes a mess of chaos around itself to stay alive."], "text_urls": [[]], "score": [4]}}, {"q_id": "7h94td", "category": "Repost", "title": "What is fire made of ?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dqp59fe", "dqp5vap", "dqpcgib", "dqp6293"], "text": ["Fire is hot gas. That's all. In the case of a wood flame, it's hot carbon dioxide, carbon monoxide, and water vapor. Take wood which has carbon and hydrogen. Add oxygen + heat, and they recombine into CO2, H2O, CO + energy. The +energy adds more heat to the flame, keeping combustion going. Since Carbon Dioxide has lower potential energy than Carbon and Oxygen by themselves, if you combine them you get energy in the form of heat and chemical energy + a newly minted molecule of carbon monoxide. If you could capture an open flame in a glass vial and then measure whats inside of it, if it were from a wood fire you'd find carbon dioxide, carbon monoxide, oxygen (from incomplete combustion), water vapor, minerals like aluminum oxide (from minerals trapped in the wood) silica, and other minerals, and trace amounts of more exotic carbon compounds like waxes, tars, etc.", "fire is flammable gas that is reacting with oxygen. when solid objects or fluids burn (paper, wood, oil, etc), the heat of the flame heats the object until it releases flammable gasses. fire is hot because the chemical bond between the atoms in the fuel and the oxygen contain more energy than the chemical bonds in the echaust gasses (usually carbon dioxide and water). the bright, red flame that is typical for candles, lighters or campfires is heated soot (small carbon particles), that is produced because there is not enough oxygen for an optimal burn process. the flame heats the soot and the soot starts emitting light. if you add more oxygen (like in a blowtorch), the flame gets hotter, but also paler and turns blue.", "Fire is NOT a hot gas (no more than gas is a hot liquid anyway). Fire is a form of plasma, constituted of ionised atoms. URL_0", "Gas. Solids and liquids don't really burn - they need to be in the gas phase. A flame is a mixture of gases. Take your common candle - the heat of the flame melts the wax, which is drawn up into the wick. It gets hot enough to vaporise into a gas, which is what you see burning. The colour of the flame is due to various types of atoms being 'excited' and their valence electrons oscillating from ground state to excited state, giving off various wavelengths of visible light."], "text_urls": [[], [], ["http://www.askamathematician.com/2013/05/q-is-fire-a-plasma-what-is-plasma/"], []], "score": [11, 5, 3, 3]}}, {"q_id": "7h96re", "category": "Repost", "title": "What exactly is dust? Where does it come from and how the heck does it get everywhere regardless of what measures you take (e.g. covering things in plastic)?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dqp5ct9", "dqpdx3n", "dqp5rts", "dqpg444", "dqpb1vr", "dqphfx1", "dqpesg3", "dqpeb80", "dqpf73f", "dqpwf06", "dqq9mni", "dqpjcnf", "dqpwbnz"], "text": ["Soil, pollen and various other really fine particles which can be blown about by the slightest breeze, meaning that they can get almost everywhere.", "The air isn't 100% clean. Microscopic particles are all around you at all times. You can see this by using a strong flashlight in a dark room. These particles consist of anything from human skin cells (which we shed daily), pollen, small human hair, microscopic space dust dust coming from space and even the roads around your house as cars break down the surface over time and that creates dust. All this enters your house when you walk inside, through vents or windows etc. and eventually settles.", "I know that inside buildings a lot of dust is composed of small shed skin particles. I\u2019m allergic to this specific form of \u201cdust\u201d and to dust mites who feed on it.", "I've been on a ship with no land in sight for two months. We cleaned everyday top to bottom and there was always plenty of dust the next day.", "Carried in to a building on people and their clothing, or entrained in air that infiltrates into the building. No normal buildings are air-tight, there is air moving in & an equal flow rate moving out, all the time. Carried in on air supplied intentionally for ventilation; clean room ventilation systems are complex and have several stages of filtration. Some places require you to wear a CSI disposable suit and shower on the way in. If you want to keep dust down, the answer is a positive pressure ventilation system, so that filtered air is supplied and more air leaks out than leaks in. There was a study done years ago ( I can't quote a source, I don't recall where I read it) examining various energy saving heating systems. Positive pressure ventilation with heat recovery was effective *IF* you included savings in cleaning labour (vacuum cleaning) and materials.", "We actually gain dust from space as well. The Earth gets heavier every year because of it... I want to say 2 cm roughly per annum.", "I'm more interested in how dust gets 'recycled' back into the environment. Something has to be getting rid of said dust or else our entire world would be one big dust bunny by now. Obviously we can physically combust it to transform it into gases, but what natural phenomena gets rid of it?", "A huge amount of the dust in your bathroom is from toilet paper. Any room with cat litter box is going to quickly become covered in clay dust", "Someone had asked one of my Science professors this specific question back in college. I believe that they said that it was the object breaking down. Objects simply break down over time and the result is dust.", "While I was in bootcamp, no one had any other clothing except what the navy provided. I noticed that every spec of dust in our berthing was blue. We spent a lot of time sweeping and my intuition told me that \"if we sweep the same hall 3 times a day, at some point we'd just be sweeping clean hallways. NOPE! There was always this blue dust, it gathered together like tumbleweed. It was from all of our uniform items, the blue fabric rubbed off from so many of us peons that it gathered in large balls everywhere. It wasn't just new uniforms, because even 6 weeks into our stay we were still seeing no reduction in this blue fluff. It came from 100's of \"sailor's\" uniforms, like when the uniform rubs against itself, between the legs and arm pits.", "It\u2019s dead skin and dust mite faeces. They shit all over us and we shed our shit laden skin everywhere. Some things are best left unknown.", "On top of the various terrestrial sources pointed out Earth also get a tiny amount of dust and tiny particles falling in from space. Estimated to about 60 tonnes worth every day. It would be a sizable heap if it all fell in one place but obviously it's spread very thinly across the whole planet so it's pretty much undetectable by the time it reach the ground (they estimate the amount by collecting samples from high altitude balloons and such).", "Take a flashlight, and shine it in a dark room. Look at the beam and you'll see lots of floating particles. Some of it can be pollen, skin flakes, dirt/soot. Those particles will eventually settle on top of a nearby surface."], "text_urls": [[], [], [], [], [], [], [], [], [], [], [], [], []], "score": [4966, 2705, 745, 296, 90, 39, 28, 10, 7, 6, 4, 4, 3]}}, {"q_id": "7he2h1", "category": "Repost", "title": "Why when were on the phone do we start to walk around aimlessly", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dqqaud3"], "text": ["It's based on primal instincts. When we are on the phone we are distracted audibly (not listening to our surroundings). In our past generations this could possibly be dangerous because of predators. So subconsciously our brain likes to walk around and check the surroundings while our conscious mind is occupied."], "text_urls": [[]], "score": [5]}}, {"q_id": "7hguy3", "category": "Repost", "title": "Why can we pop our ears, and why can we hear much better when we pop them?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dqqudc2", "dqr4q2x"], "text": ["You can hear things because there is a thin \u201cdrum\u201d in your ear that sounds make vibrate. Your brain feels those vibrations and you experience it as sound. Air cannot go through that ear drum, just like a normal drum. Air gets to the other side through a different hole deep inside your head. The amount of air around you depends on how high up you are, the higher you are, the less air. If you go up or down quickly, the different hole that goes to the other side of the ear drum doesn\u2019t let air through quickly enough, or at all if it gets clogged with goop, and the outside part of the drum (that you could see by looking in your ear) has a different amount of air pushing on it. Your brain knows how sounds work when both sides have the same amount of air, and gets confused when they have different amounts. When your ears pop, that is air moving into the inner part of your ear and making the pressure the same. Now you hear like normal again!", "The ear drum needs air pressure on its two sides to be similar in order to vibrate when sound waves hit it. Behind each ear drum is the Eustachian tube that runs from the middle ear to the back of the throat. It is there to equalize the air pressure inside and outside the ear drum. You can feel the tension on the ear drum when it is stretched due to different air pressure inside and outside the ear. For example, when you go up in a plane or drive up a tall mountain, the outside of your ear has lower pressure but the inside of your ear still has sea-level pressure. Ear drum is stretched outward. Until you yawn, sneeze or otherwise open your Eustachian tube. Going under water more than six feet causes the same sensation, but here the outside pressure is higher that the middle ear pressure, stretching the ear drum inward. Most medical drawing illustrate the Eustachian tube as if it were a rigid pipe. It is more analogous to a sock, open when on your foot, but closed when lying on the floor. When you pinch your nose and blow (a \"Valsalva\" maneuver), you temporarily inflate the Eustachian tube, opening it up and allowing pressure inside and outside the ear to equilibrate. The Eustachian tubes can get clogged. Babies, like every other part of their body, have tiny Eustachian tubes that get blocked with mucus easily (during a common cold) ... that's why one is more likely to get ear infections when younger, less often when older, when the Eustachian is bigger and harder to clog. Although some adults have small Eustachian tubes just via bad luck."], "text_urls": [[], []], "score": [7, 4]}}, {"q_id": "7hk208", "category": "Repost", "title": "The game of cricket", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dqrl9la"], "text": ["I'm going to assume you know how to play baseball, because I will use that sport as a comparison. In cricket, there is an outfield team and batting team just like in baseball. However, when a person is at bat, they keep hitting until they are out. Instead of three outs, there are ten. Also, in some types of matches, there are things called overs. An over is six pitches (iirc). The defending team switches bowlers (pitcher) every over. Anyways, some games have a limited amount of overs. So, even if the batsman doesn't get out, the attacking team retires once they reach the maximum amount of pitches. Innings work the same way, but can last for hours, even days. Depending on the type of game, they only play a couple of innings. A person can score multiple runs for each at bat. The bowler throws the ball to the batter and the batter tries to strike it. In cricket, the batsman can hit the ball in any direction, including behind him; there are no foul balls. When he hits the ball, he and another batsman (think of him as the next batter up), run between the wickets. Instead of running around four bases, think of it as the two of them running between 1st and home plate over and over again. Every time they make it across, that's a run. If the batsman hits the ball, and it rolls out of the filed, that's a called a four. It is four automatic points; it is similar to a ground rule double. If the ball is hit directly out of bounds, that's a six (six points); it is a home run. Getting the batter out is very similar to baseball. If the batter strikes to ball and it is caught in the air, that's an out. If the batters are running between wickets, but the defense team breaks the wicket before the batter is in the batting box, that's like tagging someone out at the base. If the bowlers throws the ball and it hits the wicket, that's like a strikeout, but only with a single strike. There are many more technical rules, but that is the gist of it."], "text_urls": [[]], "score": [6]}}, {"q_id": "7hmd8m", "category": "Repost", "title": "How does \u201cactivated charcoal\u201d work and why has it become so wildly popular in beauty/cosmetic products?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dqs4f2u", "dqsbva9", "dqs7rir", "dqs9rq6", "dqscmgs", "dqshcva", "dqsfmhc", "dqsa6ih", "dqsmbqw", "dqsdcf4", "dqsgnu2", "dqsjj99", "dqsjnld", "dqsff1a", "dqspl1v", "dqstaxv"], "text": ["\"Activated charcoal\" is carbon - which, you know, is what charcoal is made out of, mostly. They press it into smaller bits with more surface area. Carbon like that has a lot of porous area where chemical *adsorption* can occur. Adsorption is like absorption, kind of, in that your material is \"sucking up\" something from a liquid or gas. In the case of adsorption, atoms and molecules stick to the surface area of your material. Charcoal, particularly activated charcoal, has a *lot* of surface area, so it can adsorb a *lot* of stuff and it can do it quickly and efficiently, and also cheaply. ~~That's why they use charcoal to pump your stomach when you have alcohol poisoning. The carbon sucks up all the alcohol, then they remove the saturated carbon from your stomach, bringing the alcohol with it. What carbon remains to go through your digestive tract contains the alcohol so you can't absorb it into your blood.~~ [^^Or ^^not ^^maybe?]( URL_0 ) ^^I ^^dunno, ^^point ^^is ^^it ^^sucks ^^up ^^poisonous ^^stuff ^^in ^^your ^^stomach. It's also used in aquariums to suck up waste in the water so it can be removed when you change your filter. It's especially good at removing heavy metals, which are sometimes present in your water at concentrations that are not high enough to hurt you but high enough to hurt your livestock. Similarly, it's used in water purification systems (like your Brita filter) to similarly suck up some stuff in your tap water that you are trying to filter out. EDIT: And some gas masks, and industrial air pollution scrubbers, and a number of similar filtering applications. It's quite good at actually sucking up toxic chemicals. Just, you know...not out of your face. That tendency to suck up heavy metals has created a mystique about it, that it sucks up \"toxins\". If it can purify your water, why not purify your skin? It can suck up \"toxins\" out of your face! (Pro tip: it doesn't.) Edit: when they make you swallow charcoal for a pill overdose or swallowing poison, *it does nothing to the drugs or poison in your blood*. If you still have some left in your stomach, it soaks that up so that your OD or poisoning doesn't get any worse. What's in your blood is still there and has to be dealt with in other ways.", "Serious question. Does activated charcoal brushing powder actually do shit? On amazon i always see before and after pictures. I figured your average joe would just upload two seperate images. But these people always have a single image divided up. Seems to professinal. Seems fake. Not buying it. Seems like its all a scam.", "Take a piece of wood. Now heat it to very high temperatures in the absence of oxygen (no combustion) - this creates a very pure carbon, a charcoal. Now, expose this to an \"activating\" agent (like carbon dioxode) that creates a very porous structure that gives it a lot of surface area. The more area you have means you can adsorb (sort of like a sponge) more contaminants. Activating also alters the surface such that it is more attractive toward, specifically, organic compounds. Examples of organic compounds that would be of interest include oils and grime in your skin, tea/coffee stains on your teeth, and taste/odor compounds and organic contaminants in your drinking water (think fridge filter). Activated carbon is in the adsorbent family of treatment options. There are other options, but carbon is cheap and it can be sustainable if one uses resilient sources like bamboo or waste products such as coconut shell. A great invention would be turning waste plastic into activated carbon, something many are working on! *How much surface area? The amount of AC that fits in your palm (or half a banana, if you must) is equivalent in surface area to about five football fields.", "Carbon is porous and acts like a filter that small tidbits will stick to. It doesn't actually do anything, for your skin, better than washing. The reason it's so popular in skin care is because of marketing.", "Can anyone confirm if this actually works for beauty products? Mostly interested in the effectiveness of whitening your teeth with it? I always heard baking soda works but then my dentist told me it scratches your enamel (which doesn\u2019t heal) because baking soda is too rough and not ground up finely enough. So then, what are the cons of charcoal teeth whitening, if it does work?", "So, lots of comments asserting that activated charcoal doesn't actually adsorb toxins off the skin. 'Toxins' is, of course, a nebulous, sort of meaningless term in this context, so that doesn't surprise me. But does charcoal in a skin-care product really not adsorb things like the bacteria that can cause ance, or excess sebum and oil that can block pores and cause breakouts? In my own experience, some charcoal face-wash scrubs I've tried were quite potent at cleaning oily skin. Maybe even too strong.", "Unlike a fine silica gel which attracts very polar oils and chemicals, charcoal (carbon) is very non polar and attracts very non-polar oils and chemicals to it, including some stains as well. Pharmaceutical companies use it while making certain drugs to make their pills more uniformly white since people would rather take a white pill than a tan or brown pill. For cosmetics I assume for cleaning purposes it adds a benefit of adhering to and eliminating certain otherwise stubborn lipids or oils that don't clean up well with soap and water; also maybe to eliminate the oil built up in natural creases in the skin crafting the illusion that someone looks younger due to their wrinkles being less prominent. Wanting to look younger is a thing right?", "The charcoal serves to absorb toxins and stains but will not actually whiten your teeth. Teeth color comes from the color of \u201cdentin\u201d which is a layer underneath the surface of your teeth. Things like whitestrips will bleach/stain the dentin white. Almost everyone has naturally off-white/yellow natural teeth. Active charcoal will just get your teeth as \u201cwhite\u201d as your teeth naturally are, but won\u2019t give you that Hollywood smile.", "Taking charcoal pills regularly is very much NOT recommended outside of prescribed medical use. If you are on any kind of daily medication, activated charcoal can prevent your medication from being absorbed properly - antidepressants, birth control, antihistamines, etc, can all be rendered less effective by taking charcoal along with your prescribed dose of medication. Furthermore, taking activated charcoal internally has never been shown to provide any medical benefit as part of a daily routine, and can actually be harmful if taken with food as it may prevent essential nutrients from being absorbed. It's just another marketing fad selling you snake oil. Don't be fooled!", "Activated Charcoal is porous and it attaches to other molecules. It is used to neutralized poisons in an Emergency room. The Efficacy on it's use everyday for hygienic reasons is most likely that it is has harmful effects. I would not purchase these products. Activated Charcoal would make other topical and internal medicines less effected.", "Regular carbon (charcoal) has small nooks and crannies that capture impurities. Activated carbon is charcoal that has been crushed, soaked in acid and baked. This process makes the carbon bits smaller and the are now microscopic if not smaller nooks and crannies that can now capture even more impurities. Like a billion times more crevices and also captures smaller impurities. Not sure about it being in makeup though.", "Activated charcoal: Its a marketing term for \"activated carbon\" which is a processed form of carbon thats more poreous than other forms of carbon, thus allowing certain thigns to be absorbed into it easier. What it is used for in cosmetics: It has been in use for hundreds of years and has become more available in modern times for use in hospitals etc. It can be used as a cleanser, mask, and many other products. Why is it popular: Marketing has rediscovered this term for use in cosmetics. People who don't know any better are paying a few extra dollars on something that is not necessarily more effective than other cleansers. People will buy anything that are marketed to make you look younger without really doing any solid research.", "Is this why my whiskey says triple-filtered with active charcoal?", "Is it okay to use charcoal toothpaste very sporadically? Like weeks before another use?", "As a layman, where do i read stuff about what's really good for our health/skincare? is there a kind of honest ebook i could look up to? I highly sceptical of those product marketing or people claiming a particular compound is secret for everlasting beauty.", "Wendy Zuckerman did a good show on this on [science vs]( URL_0 ). It has become wildly popular in beauty/cosmetic products because it's easy to make wild claims that are plausible-sounding enough to get people to part with their money. It is used medically to treat certain poisonings and overdoses following oral ingestion. If you can convince people that their self-perceived flaws are caused by something as intensely unlikable as \"toxins\", you can easily convince them to spend their money on your activated charcoal. It's benign enough not to hurt you, so why not? The reason it's effective for things it's *truly* effective for is that the process of \"activating\" it gives small particles a large surface area that allows it to absorb a much larger amount of contaminants than it would otherwise, so you can get away with using much smaller amounts."], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/7hmd8m/eli5_how_does_activated_charcoal_work_and_why_has/dqs6r6a/"], [], [], [], [], [], [], [], [], [], [], [], [], [], [], ["https://gimletmedia.com/episode/detoxing-cleanses-work/"]], "score": [6589, 498, 362, 176, 153, 57, 25, 13, 7, 6, 5, 4, 3, 3, 3, 3]}}, {"q_id": "7hv1wu", "category": "Repost", "title": "why do so many stores in the U.S. sell things with a .99 at the back? E.g. 9.99, 1.99, 999. Why not just use 10.0, 2.00, 1000?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dqu18br", "dqu1aue"], "text": ["It\u2019s a technique used to make the average person think at a first glance that $1.99 is not $2 and is only $1. Sorry if this is explained bad, I heard this from my 7th grade teacher", "This is a classic marketing trick that makes you think the item is cheaper than it actually. Your subconscious latches onto the first digit and your purchase seems more justified despite the almost insignificant change in price. Also in the U.S. the tax isn't included in the sales price so the total price is usually over the even price anyway (Ex: $10.08"], "text_urls": [[], []], "score": [5, 3]}}, {"q_id": "7hx1a2", "category": "Repost", "title": "how can a device be turned off for years, but when it's turned back on again it still knows the date?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dqufu5r"], "text": ["Electronic devices have a clock they use to keep time, and a battery to keep track of the time. So your PS4 knows what the time was last time it was on and how long it's been since then."], "text_urls": [[]], "score": [5]}}, {"q_id": "7hzhud", "category": "Repost", "title": "how hacking works, since it seems to be misrepresented in most movies?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dquy0hc", "dquy440"], "text": ["Hacking refers to a wide variety of activities. You might as well be asking \"how theft works.\" Generally speaking: 1. You perform reconnaissance on the target. Gather as much information as you can. 2. You identify weaknesses or vulnerabilities. 3. You develop a pan of attack to exploit those weaknesses and vulnerabilities. 4. You execute the plan, taking measures to avoid notice or leave a trace. What is misrepresented is that a lot of hacking research. Imagine filming someone doing a book report for school. A lot of hacking involves less-than-technical methods. Such as social engineering and tried-and-true real-world techniques like dumpster diving. For parts of hacking that involves software much of it is automated. Most tools used don't have flashy interfaces, nor is a real-time back-and-forth battle of wits between a hacker and IT security.", "I work for a computer security company and deal with this kinda stuff all day, so here's the short version. There's two ways to do it, essentially. Trick a human, or find a mistake in the way a machine works and take advantage of it. In the case of human tricking, this is phishing emails asking for usernames/passwords, \"hey download & run this totally-not-a-virus-thing please\", \"hi I'm bob from Microsoft please give me your password for a security check thanks\", and other such scams. Frequently, that works just fine. You can also just try logging into websites and other services and hope someone set their password to \"password.\" And yes, that frequently works just fine too! No enormous technical skills required! As for \"real\" hacking... a lot of websites, services etc rely on the same basic components. Linux & Windows are super-common, web server programs like Apache or Microsoft IIS... these tools are all working behind the scenes to power the modern web. So what someone does is gets their hands on one of these (not hard) and starts poking around to find an \"exploit.\" A good example of an exploit was the [heartbleed bug a few years ago, which xkcd made a comic explaining.]( URL_0 ) Basically, they discovered a bug that would make OpenSSL (a very common program) cough up too much information. Then, now that you KNOW about this exploit, you use it against real-world servers run by actual companies, in the hopes that one will unintentionally spit out somebody's password. Other exploits often let you run code when a server shouldn't be letting you run code. So you build a little package designed to get run by the exploit, and once that lil package gets to run, it sits and listens for you to give it more commands to run on the remote computer, letting you change passwords, access lists etc so you can login for real. And that'd be a type of virus! There's a lot to cybersecurity but hopefully this helps scratch the surface"], "text_urls": [[], ["https://xkcd.com/1354/"]], "score": [3, 3]}}, {"q_id": "7i45d5", "category": "Repost", "title": "How was the internet made? Like how did they discover coding, etc?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dqvzwvk"], "text": ["Computers predate the internet by several decades, but the origins of the internet can be traced back to a US Military project in the 1960's called Arpanet. They wanted to see if they could get computers to communicate with each other. The first data packet was sent from a computer at UCLA to one at Stanford in 1969. The technology that came out of Arpanet ultimately led to the commercial internet."], "text_urls": [[]], "score": [3]}}, {"q_id": "7i4j0n", "category": "Repost", "title": "What is a stroke, and what causes it.", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dqw2u7l", "dqw2hm0"], "text": ["Your brain requires an immense amount of oxygen and energy to continue functioning. And it requires it nearly continually. A stroke is a blockage of the blood flow to the brain. This results in the parts of the brain that the blood is flowing to to become negatively affected. Usually this is on one side of the brain or the other, which is why you see unequal movement or strength in one side of the body. As blood flow continues to be restricted, brain damage can occur, which is why responding to a stroke quickly is so important. Don't forget FAST! FACE (Ask the potential victim to smile, if it is uneven, that's the first sign) ARM (See if one arm is weaker than the other. The best way is to ask them to hold their arms in front of them and level. If they are unlevel, that's another sign.) SPEECH (If their speech is slurred, that might be the first sign you notice. If you're not sure, ask them to talk a bit.) TIME (If you think a stroke is possible, call emergency services right away. Better to be safe than sorry in a stroke.) There are a few other quick checks: Have them stick out their tongue straight forward. IS it uneven? If so, it's another sign. Also, you can have them cover one eye. If they say their vision is suddenly worse with one eye, it is another sign. Strokes don't just affect older people. I've lost two friends in the last year to cardiovascular disease, and both were under 40.", "A stroke is when part of your brain has no blood circulation. This causes parts of your brain to die. Strokes can be caused by blood clots or other blockages blocking off the way of the blood flow or even bleeding in the brain (blood is just pooling around the brain instead of going where it needs to go)."], "text_urls": [[], []], "score": [8, 3]}}, {"q_id": "7i8p53", "category": "Repost", "title": "How does radiation kill cancer cells without mutating normal cells?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dqwwyy5", "dqwx2gp"], "text": ["They use gamma rays, which largely pass through the body. Then, they fire those rays in multiple bursts from multiple directions, each aimed at the tumor but from a different direction. This ensures, that only the tumor is hit multiple times, the rest of your body is only hit once. Thus, the amount of radiation absorbed by the tumor is much higher than that absorbed by healthy cells.", "It doesn't. Radiation used to fight cancer is dosed high enough to kill all cells, cancerous or not. The idea is to concentrate it into areas where the cancer is rather than healthy areas."], "text_urls": [[], []], "score": [11, 5]}}, {"q_id": "7i8sfs", "category": "Repost", "title": "Last night I woke up and was unable to move for a few seconds. It felt like something was holding me down. I couldn't even speak. Then a couple seconds latter I was completely fine. Is there a name and explanation for this phenomenon?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dqwxk3u"], "text": ["Sleep paralysis is a temporary inability to move or speak that occurs when you're waking up or falling asleep. It's not harmful and should pass in a few seconds or minutes, but can be very frightening."], "text_urls": [[]], "score": [9]}}, {"q_id": "7ia59y", "category": "Repost", "title": "what exactly do antioxidants do?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dqx9515"], "text": ["Practically all cellular processes have a needed initiator and a consequential product. These cellular processes are chemical processes with a lot of variation going on. They don't also go perfectly. There accidental or uncontrolled products which can form a chemical product called a radical - a compound missing an electron. This is a HUGE issue, because compounds want to be stable, and missing an electron will make that compound react with whatever is closest to it, that fits some properties it likes. Its a little like, a product of one of these reactions is a firecracker that destroys a functioning unit in your cell when it touches it. Not good. These are called oxidized species - its just terminology. A way to remove this issue to is to add a reducing agent - a compound which will give up an electron, or even form a stable compound with an oxidized agent. You would like these to be safe to our cells regular function, and to interact with the radicals. If you can give your cells antioxidants, you can both prevent the destruction of a functional unit, and create a safety buffer so that if one does happen, it'll react with something not-critical. Thus, they are good for us because they protect our cells from the inevitable damage which happens due to the small chemical errors in our natural system. This allows the cells to live longer and not have any complications, improving our over-all health."], "text_urls": [[]], "score": [5]}}, {"q_id": "7iabpj", "category": "Repost", "title": "Who decides when (for example) the Canadian dollar goes up and down in worth? And how does that work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dqxa6qi"], "text": ["Foreign exchange markets. Let's pretend I have 100 USD and 100 CAD. At the moment I write this it's 100 CAD = 77.8 USD. If I wanted to have only USD, I am selling my 100 CAD to a foreign exchange service to receive 77.8 USD minus some sort of exchange service fee. Let's now pretend I have 100 billion USD and 100 billion CAD. Let's say I sold the 100 billion CAD. I would likely get significantly less than 77.8 billion USD, because the act of my selling this quantity of CAD for dollars has significantly increased supply of the canadian dollar while simultaneously increasing demand for US dollars. The exchange rate would move by a good amount, so that 100 CAD would be worth significantly less than 77.8 USD. That's how foreign exchange markets work - the relative demand of currencies. Why some currencies are in demand and not others is not something really answerable in a ELI5 way."], "text_urls": [[]], "score": [5]}}, {"q_id": "7icdpo", "category": "Repost", "title": "What exactly happened during the Enron Scandal in 2002?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dqxsphn", "dqxqvqc", "dqxv0wc"], "text": ["In trying to make their oil company cool, they wanted to think of themselves as a trading firm. So they started doing things like trading energy or Internet traffic. Because of their mindset, all they cared about the cash on the books at the end of each quarter. In order to get cash on the books when they had none, they devised many accounting tricks to increase the cash on the books and decrease losses. Not in reality, just in reporting. For example, they would sell portions of loss making subsidiaries, where there was some weird rules like if they sold a tiny fraction of the subsidiary, then they won't be the owners and not have to report the losses. Something like sell 7% of a electric plant and not have to report loses of that. In addition, the would write down all potential gains in the first year of contract. Like if they had a contract in 1997 to provide water to a region for 7 years, they guessed your much money they would make from that over the seven years and book all the potential profits in the first year. Regardless if they ever made any money or profit, they didn't go back and revise down. So it looked like they made a lot of money. Back to the selling assets, their CFO, while CFO, started a hedge fund which would be the place that Enron would sell their fractions troubled assets. As CFO, he was able to negotiate both sides of the deal, and because Enron was desperate to unload losses from their sheets, they would sell at a very bad price for Enron, and a great price for the hedge fund. Many of the investors in the hedge fund were employees of Enron, or bankers who wanted to do business with Enron (the CFO would give them preferential treatment). Check out book and or documentary \"smartest guys in the room\"", "They started hiding their losses in crazy accounting methods and then lost more and then did crazier accounting tricks.", "The energy markets were deregulated. Essentially, what that means is that instead of there being fixed rules on power generation and sales, power could be bought and sold by speculators on a market. So essentially, what used to be a system where a power plant might sell energy to the grid at a fixed price, there was a constantly fluctuating price of energy being bought and sold. So at 8am maybe energy is only $0.12/kwh, but maybe at 8:30 it's now $0.25/kwh, and maybe for 3 minutes at 6:23pm it's $5/kwh. Electric companies have to pay the \"market rate\" to provide the power. Because buying and selling energy on a market used to be governed by rules, and now it was not, Enron could do all sorts of things to make money. They could lock all the power producers into markets they owned, forcing them to sell at the constantly changing rate to electric companies. So Enron could then make money on each little transaction, like a stock market might. But because there was no regulation, Enron could act like a buyer of energy and a deliverer of energy if it wanted. So Enron could make money by promising to buy natural gas at some rate (say $1), and then if the market went up, then they could sell it at $2, still paying the producer the agreed upon $1. What happened is that they started using fishy accounting practices. For example, if they were buying 1000 CCFs of natural gas at $1 today and next year selling it at $2, then they'd write on today's books that they made $1000, even though they never sold it next year. When next year rolls around, they have a problem if gas is still $1. Obviously, that can only last so long before it's discovered, but the guys at Enron were really pretty smart, and so they were making tons of money other ways, and also coming up with more creative ways to make it look like Enron was still making money on these contracts that seemed like they were worth more than they really were. The most creative of these was to create another company who was \"buying the loss\" which essentially allowed them to show that Enron was doing good, but this other company had all of those -$1 losses from the market not rising like it was promised. That company was hidden from all the investors, so it wasn't obvious that it was a part of Enron. Eventually, like all houses of cards, it was discovered that Enron didn't have all the money it claimed it did, and then it went bankrupt - but that disrupted companies who were buying their energy on their market (electricity, natural gas), which is why it turned into such a big deal. It was also difficult as Enron was a Fortune 500 company that would have been thought to be too large to fail so suddenly."], "text_urls": [[], [], []], "score": [19, 4, 4]}}, {"q_id": "7igb6i", "category": "Repost", "title": "Why has it been so difficult to unseat the big ticket sellers (like Ticketmaster) and start a new ticket system?", "title_urls": {"url": []}, "selftext": "I feel like people have been hating on Ticketmaster since they existed, but I have never seen another company unseat them, or band/label change the way they sell tickets. I mean, we seen Uber disrupt the taxi system, which was once considered unchangeable. Any thoughts?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dqykqq0", "dqykfr8", "dqykbnx"], "text": ["What would you have to do to displace Ticketmaster? 1) Start a new company to serve the same market, this would require a significant capital investment. 2) Convince venues to break their highly profitable contracts with Ticketmaster - or at least switch to you as renewal time. This would require taking a smaller cut than Ticketmaster takes. 3) Convince consumers that your service doesn't have the same problems as Ticketmaster. You still can only sell the tickets allocated to you, so all those \"good seats\" the promoter and venue reserve for themselves aren't available for your customers. If you can't solve the \"didn't get the tickets I wanted\" problem, you're going to do it for a smaller fee?? 4) Demonstrate to the marketplace that you can sell tickets as fast as Ticketmaster, which will require quite a bit of IT. Your basic concept is to make a huge investment for less return and sell it at lower prices - that's not disruptive, it's going out of business. If you do well for a while, your investors are going to get a purchase option from Ticketmaster, and you're going to be sold out to them. Think about what you hate about Ticketmaster - it's not something that can be fixed because Ticketmaster is a very efficient company. People just like to complain that they can't get to sit down front.", "Yo ho ho! Yer not alone in askin', and kind strangers have explained: 1. [ELI5 - How is it that Ticketmaster seems to have a total monopoly over all things tickets, or, why does it cost $18 to mail me tickets? ]( URL_3 ) 1. [ELI5: Ticketmaster ]( URL_1 ) 1. [ELI5: What necessary service do companies like TicektMaster provide? ]( URL_5 ) 1. [ELI5: Why isn't there a viable alternative to Ticketmaster? ]( URL_7 ) 1. [ELI5: Why do so many events sell tickets through ticketmaster instead of through their own website? ]( URL_0 ) 1. [ELI5: How does event ticketing work, i.e., What economic principles allow Ticketmaster to charge such high fees for such an easy task? ]( URL_8 ) 1. [ELI5: Why doesn't Ticketmaster have any real competition and why isn't it considered an illegal monopoly? ]( URL_2 ) 1. [ELI5: How is Ticketmaster able to avoid Monopoly laws? ]( URL_6 ) 1. [If everyone hates Ticketmaster, why doesn't it have any real competition? ]( URL_4 )", "The [latest episode of Freakonomics Radio]( URL_0 ) speaks directly to this topic. I haven't listened to the whole thing yet, but the gist I've gotten so far is that Ticketmaster takes the brunt of the bad PR for charging fees, but sees very little of those fees. Also, there is the \"fact\" that live show ticket prices are SEVERELY under-priced. If you're interested in a real answer to this question I recommend listening to the podcast."], "text_urls": [[], ["https://www.reddit.com/r/explainlikeimfive/comments/1muw5n/eli5_why_do_so_many_events_sell_tickets_through/", "https://www.reddit.com/r/explainlikeimfive/comments/3tp7tv/eli5_ticketmaster/", "https://www.reddit.com/r/explainlikeimfive/comments/kq5ys/eli5_why_doesnt_ticketmaster_have_any_real/", "https://www.reddit.com/r/explainlikeimfive/comments/qqdps/eli5_how_is_it_that_ticketmaster_seems_to_have_a/", "https://www.reddit.com/r/NoStupidQuestions/comments/4298zg/if_everyone_hates_ticketmaster_why_doesnt_it_have/", "https://www.reddit.com/r/explainlikeimfive/comments/4a8fok/eli5_what_necessary_service_do_companies_like/", "https://www.reddit.com/r/explainlikeimfive/comments/1j0xa3/eli5_how_is_ticketmaster_able_to_avoid_monopoly/", "https://www.reddit.com/r/explainlikeimfive/comments/3mcff5/eli5_why_isnt_there_a_viable_alternative_to/", "https://www.reddit.com/r/explainlikeimfive/comments/44io31/eli5_how_does_event_ticketing_work_ie_what/"], ["http://freakonomics.com/podcast/live-event-ticket-market-screwed/"]], "score": [12, 7, 4]}}, {"q_id": "7iggza", "category": "Repost", "title": "How do they decaffeinate coffee and tea?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dqyk324"], "text": ["Yarr! Yer not alone in askin', and kind strangers have explained: 1. [How is the caffeine removed from decaffeinated tea and coffee? ]( URL_6 ) 1. [ELI5: How do they decaffeinate coffee and teas? ]( URL_2 ) 1. [ELI5: How do they take the caffeine out of tea and coffee to make decaffeinated versions? ]( URL_4 ) 1. [How do they make decaffeinated tea and coffee? ]( URL_3 ) 1. [ELI5: What is caffein and how can it be removed from coffee? ]( URL_8 ) 1. [ELI5: How is coffee decaffeinated? ]( URL_1 ) 1. [ELI5: How do they decaffeinate coffee? ]( URL_0 ) 1. [ELI5: How do you decaffeinate coffee. ]( URL_7 ) 1. [ELI5: How do they decaffeinate coffee? ]( URL_5 ) 1. [ELI5: Decaffeinated coffee ]( URL_9 )"], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/554eqb/eli5_how_do_they_decaffeinate_coffee/", "https://www.reddit.com/r/explainlikeimfive/comments/3o1mys/eli5_how_is_coffee_decaffeinated/", "https://www.reddit.com/r/explainlikeimfive/comments/2nslza/eli5_how_do_they_decaffeinate_coffee_and_teas/", "https://www.reddit.com/r/explainlikeimfive/comments/1v7f9y/how_do_they_make_decaffeinated_tea_and_coffee/", "https://www.reddit.com/r/explainlikeimfive/comments/2rwo0n/eli5_how_do_they_take_the_caffeine_out_of_tea_and/", "https://www.reddit.com/r/explainlikeimfive/comments/5qhy0i/eli5_how_do_they_decaffeinate_coffee/", "https://www.reddit.com/r/NoStupidQuestions/comments/6zaxvl/how_is_the_caffeine_removed_from_decaffeinated/", "https://www.reddit.com/r/explainlikeimfive/comments/2b289f/eli5_how_do_you_decaffeinate_coffee/", "https://www.reddit.com/r/explainlikeimfive/comments/2gojnv/eli5_what_is_caffein_and_how_can_it_be_removed/", "https://www.reddit.com/r/explainlikeimfive/comments/5k34g2/eli5_decaffeinated_coffee/"]], "score": [4]}}, {"q_id": "7ih6ch", "category": "Repost", "title": "Why do our noses run when we are outside when it is really cold?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dqypa6m"], "text": ["I remember asking my parents this when I was little, and they said something like the nose is trying to keep itself warm and moist, because cold air is often dry, and when your nose gets really cold it can't tell if it's dry or not. I'd be interested to hear from the pros if that's the case or not."], "text_urls": [[]], "score": [6]}}, {"q_id": "7ijqbj", "category": "Repost", "title": "Why does wind chill exist?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dqz9xit"], "text": ["Ever put a tea bag into water? Notice how the tea sticks close to the bag at first? But then you stir it and the tea goes everywhere. Same with body heat. It dissipates but stays close to you until the wind blows (especially under your clothes). The wind blows that heat away and therefore the temperature right next to your skin gets colder even though the temp of the air is the same"], "text_urls": [[]], "score": [3]}}, {"q_id": "7ikquq", "category": "Repost", "title": "How does a car know how fast it\u2019s going?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dqzh924"], "text": ["Ahoy, matey! Yer not alone in askin', and kind strangers have explained: 1. [ELI5: How does a car know how fast it's going? ]( URL_0 ) ^(_11 comments_) 1. [ELI5: How do cars know how fast they're going? ]( URL_3 ) ^(_16 comments_) 1. [ELI5: How do cars know how fast they are going? ]( URL_9 ) ^(_8 comments_) 1. [ELI5: how exactly does a car's speedometer work? ]( URL_6 ) ^(_7 comments_) 1. [ELI5: How does a speedometer know how fast you are traveling? ]( URL_7 ) ^(_4 comments_) 1. [ELI5: How does a car measure it's speed to show up in the speedometer? What happens if the car is replaced with wheels of different diameters? Does it matter? ]( URL_1 ) ^(_17 comments_) 1. [ELI5: How does car's speedometer & tachometer work? ]( URL_4 ) ^(_13 comments_) 1. [ELI5: How does a speedometer work? How are they able to adjust it to mph vs kmh? ]( URL_5 ) ^(_7 comments_) 1. [ELI5: How does a cars speedometer work? ]( URL_8 ) ^(_19 comments_) 1. [ELI5: How do speedometers work? ]( URL_2 ) ^(_5 comments_)"], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/6iu1si/eli5_how_does_a_car_know_how_fast_its_going/", "https://www.reddit.com/r/explainlikeimfive/comments/1uwq23/eli5_how_does_a_car_measure_its_speed_to_show_up/", "https://www.reddit.com/r/explainlikeimfive/comments/5ug54o/eli5_how_do_speedometers_work/", "https://www.reddit.com/r/explainlikeimfive/comments/6xiw9i/eli5_how_do_cars_know_how_fast_theyre_going/", "https://www.reddit.com/r/explainlikeimfive/comments/791tz7/eli5_how_does_cars_speedometer_tachometer_work/", "https://www.reddit.com/r/explainlikeimfive/comments/4dnn28/eli5_how_does_a_speedometer_work_how_are_they/", "https://www.reddit.com/r/explainlikeimfive/comments/1q4zyl/eli5_how_exactly_does_a_cars_speedometer_work/", "https://www.reddit.com/r/explainlikeimfive/comments/4157kv/eli5_how_does_a_speedometer_know_how_fast_you_are/", "https://www.reddit.com/r/explainlikeimfive/comments/2iy8ti/eli5_how_does_a_cars_speedometer_work/", "https://www.reddit.com/r/explainlikeimfive/comments/1dimpp/eli5_how_do_cars_know_how_fast_they_are_going/"]], "score": [5]}}, {"q_id": "7ilwhu", "category": "Repost", "title": "Why do some people have better cold or heat tolerances than others?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dqzpiih"], "text": ["Because we're tougher. Nah it's a combination of a few things but weight, circulation and practice/familiarity are major factors. If you don't keep your heating on all the time you just get used to it"], "text_urls": [[]], "score": [5]}}, {"q_id": "7imgg2", "category": "Repost", "title": "Why did 20th century bombs dropped from aircraft usually made high-pitched, loud whistle-like sounds while falling?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dqzsrez", "dqzu577"], "text": ["The whistles were purposefully attached to the bombs. Their purpose was to weaken enemy morale and to enhance the intimidation of dive-bombing. Look at the Stuka dive-bomber, a similar case. What other purpose did it's sirens have? As far as warning the target, it's too late to get to safety once you hear the whistle if you're not there already (bombs fall fast). Not all bombs were equipped with whistles, but they still all made noise as they fell due to air displacement (just not the famous whistling sound). This ( URL_0 ) page gives one example of bombs that were purposefully fitted with whistles.", "Because it's terrifying - imagine being on the ground and hearing the whistle. You know that a bomb is coming, but there is no way you can see it, and even if you could working out which direction its moving would be impossible. The modern sniper rifles deployed in Iraq got a similar fearsome reputation because of their extreme range - you'd be minding your own business and a wall behind you explodes before you even hear the gunshot. Where did it come from? No idea. What can I use for protection? Nothing, the fucker goes through walls and sandbags."], "text_urls": [["https://en.wikipedia.org/wiki/Junkers_Ju_87#Ju_87B"], []], "score": [37, 29]}}, {"q_id": "7in216", "category": "Repost", "title": "What causes that feeling in joints that makes you want to crack your neck? Why is cracking your neck so satisfying and addicting?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dr008yr"], "text": ["Yo ho ho! Yer not alone in askin', and kind strangers have explained: 1. [Why does cracking / popping your back feel so good? ]( URL_2 ) ^(_47 comments_) 1. [ELI5: Why does cracking your knuckles/back/neck feel good? ]( URL_1 ) ^(_29 comments_) 1. [ELI5: why does cracking your neck and fingers feel so good? ]( URL_8 ) ^(_4 comments_) 1. [ELI5: What cracking your neck actually does. ]( URL_0 ) ^(_2 comments_) 1. [ELI5: What happens when you pop your neck and is it dangerous to do to yourself? ]( URL_6 ) ^(_5 comments_) 1. [ELI5: What exactly happens when you \"pop\" your neck or any other body part? ]( URL_7 ) ^(_26 comments_) 1. [ELI5:What happens when I crack my neck/back, and why does it give me relief? ]( URL_5 ) ^(_2 comments_) 1. [ELI5: Why do we feel relief when we \"crack\" our knuckles/joints? ]( URL_3 ) ^(_20 comments_) 1. [ELI5:What happens when I crack my neck? Why does it feel better than just stretching? Is it harmful or helpful?? ]( URL_4 ) ^(_1 comment_)"], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/49tfu0/eli5_what_cracking_your_neck_actually_does/", "https://www.reddit.com/r/explainlikeimfive/comments/2m2fmp/eli5_why_does_cracking_your_knucklesbackneck_feel/", "https://www.reddit.com/r/NoStupidQuestions/comments/5srdvz/why_does_cracking_popping_your_back_feel_so_good/", "https://www.reddit.com/r/explainlikeimfive/comments/597spn/eli5_why_do_we_feel_relief_when_we_crack_our/", "https://www.reddit.com/r/explainlikeimfive/comments/1mvee7/eli5what_happens_when_i_crack_my_neck_why_does_it/", "https://www.reddit.com/r/explainlikeimfive/comments/1lcney/eli5what_happens_when_i_crack_my_neckback_and_why/", "https://www.reddit.com/r/explainlikeimfive/comments/5jfmq7/eli5_what_happens_when_you_pop_your_neck_and_is/", "https://www.reddit.com/r/explainlikeimfive/comments/6eqxfb/eli5_what_exactly_happens_when_you_pop_your_neck/", "https://www.reddit.com/r/explainlikeimfive/comments/6ui7kq/eli5_why_does_cracking_your_neck_and_fingers_feel/"]], "score": [6]}}, {"q_id": "7ip7ke", "category": "Repost", "title": "the difference between 4 Wheel Drive and All Wheel Drive.", "title_urls": {"url": []}, "selftext": "Edit: I couldn\u2019t find a simple answer for my question online so I went to reddit for the answer and you delivered! I was on a knowledge quest not a karma quest- I had no idea this would blow up. Woo magical internet points!!!", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dr0d956", "dr0oxdr", "dr0e3hc", "dr0dbzv", "dr0nidn", "dr0e1n1", "dr0d2mr", "dr0rma4", "dr0euyw", "dr0g5yo", "dr0i32n", "dr0evl7", "dr0t97s", "dr0un9z", "dr0l0jz", "dr10ei7", "dr0p6yj", "dr0g2r9", "dr0qob4", "dr0qc3c", "dr0n4xf"], "text": ["4WD and AWD roughly do the same thing but in different ways, the car is proving power to all four of its wheels. The difference is how that power is divided between them. An all-wheel-drive car can allow each wheel to turn at a different rate, while a four-wheel-drive car generally has its wheel all turning at the same rate. This 4WD set up is better for offroad driving, but can cause problems in city driving, where the inside wheels need to turn slower around a corner than the outside wheels do. Because of this, a lot of 4WD cars are designed to be able to switch to rear-wheel drive when the 4WD is not needed. EDIT: RIP my inbox", "This is actually a very complex question with a very complex answer but by the time you're done with this comment you will understand it as well as anyone. So buckle up, tape your eyelids open, and go brew a bucket of coffee. To begin you need to have a good idea of how a differential works and what it is. As usual in the car world, the best way to learn is to watch a video from the 1930's (really, it is, I swear). Namely [this one]( URL_0 ). You're back? Good. That's what we call an open differential. It's the most basic type of differential. When you get stuck in the snow or mud and one wheel spins like mad and one does nothing at all, that's because there's an open differential. A ***limited slip differential, or LSD***, is a differential that allows the wheels to only turn at a limited range of different rates. If one starts to spin too much faster than the other, the differential sends power to the other wheel. Some LSD's are clutch pack type, where the speed imbalance causes the spinning wheel to be braked against the inside of the differential housing using a clutch pack. You don't really need to know how that works mechanically, but understand the effect is the same as if you were to apply the brake on just that wheel (a thing some cars actually do- brake based torque vectoring, which we'll get into later.) Others are of the \"torsen\" type, which is short for \"torque sensing.\" It uses magic, I think, but if you're in a torsen equipped vehicle, and one wheel is spinning uselessly, you should try lightly applying the brakes, as this will cause the torsen differential to send power to the other wheel, using magic. Anyone who's watched my cousin Vinny could have probably skipped the last two paragraphs. A ***locking differential*** is an open differential which has the additional ability to be locked so that both wheels turn at the same rate no matter what (unless you try to use it on dry pavement, then it'll probably break). A ***viscious coupling*** uses a fluid coupling of some sort to distribute power between the wheels. Usually using a computer. Some viscious couplings are made of stacks of plates attached to the input and output shaft alternately, and by squeezing them closer together, the viscosity of a fluid causes power to be transmitted from the input to the output. Others can work like a torque converter in a transmission, where fluid is splashed by one plate onto another, pushing the second plate. [If you care to learn how torque converters work you can watch this old army video, but it's not really applicable here. Still well worth a watch]( URL_1 ) A ***wet clutch*** works a bit like brakes, but backwards. If you've ever driven a manual, you have an idea of how a clutch works, but a wet clutch is full of oil too, so it doesn't wear out and can handle continuous slipping. This may be used when you want to allow a computer to dole out power to each wheel individually as it chooses. If you watched the video above (you did, right? Right?), you know that the wheels have to turn at different rates on the driven axle, but you might not know they also need to turn at different rates between the front and the rear axle. So if we want to drive the front and rear wheels, we need a differential for the front wheels and a differential for the rear wheels as well as a differential between the front and rear axles. This is where things start to get really complicated and you'll see that 4wd and Awd are just marketing terms developed because it's easier than explaining the myriad of differences to non-enthusiasts. You've made it this far, so keep going. Let's start with 4 wheel drive. 4 wheel drive generally implies that there is a degree of selectability, and something's getting locked to something. Because of the need for each axle to turn independently, most 4 wheel drive systems are 2 wheel drive almost all the time. When you get stuck, you select 4 wheel drive, and you're out. This is done with the transfer case. Usually the transfer case will allow you to select 4 Hi, 4Lo, N, and 2Hi. 4Hi is for driving at speed in 4 wheel drive on a surface that will allow the wheels to slip, such as snow or gravel. 4Lo is for when you're stuck and you want to not be stuck, or you're crawling along in really rough terrain and you need torque, not speed. N is just neutral, and 2Hi is 2 wheel drive, high range, and is just what you'd normally use putting around town. Putting the car into anything but 2Hi on tarmac is a great way to make my day, because I'm a mechanic, and I like nice things. Because the axles need to turn independently and they can't, you go around a corner, get a nice loud crunch, and get to check if your AAA membership is still valid. Now some vehicles don't use a selectable transfer case like that. Instead the front differential is always driven. What you do is you lock the front wheels to the differential at the hubs, and unlock it when you don't want 4 wheel drive. But this generally requires getting out of the truck and that's not nice. Some cars do this on their own using a computer or mechanical system. So now you can send power to the front and rear axles. Most of the time this is great. But what if one wheel on each axle is on snow and the other is wedged up against a rock? You're still not going anywhere. Now you need locking differentials. Note that simply having 4 wheel drive doesn't mean you have locking differentials. See? Marketing mumbo jumbo. So that's 4 wheel drive. What about all wheel drive? Well, the system varies from car to car. Awd is a blanket term that means all of the wheels can be driven at some point or another. Note that in 4 wheel drive, power comes out of the engine, into the transmission, out of a driveshaft, into the transfer case, and then out into a front and rear driveshaft. All wheel drive may do that, or it may send the rear wheels power from the back of the transmission, and the front wheels power from the sides. It's truly a clusterfuck of variability. The most simple type of all wheel drive is an open differential for the front wheels, an open differential for the rear wheels, and an open differential to spilt the power between each axle. This is marginally more useful than 2 wheel drive, but only just. See, if even 1 wheel has no grip, you're not going anywhere. Unless the car has good brake based torque vectoring (that works, which is a crapshoot as well, as some cars have shitty brake based torque vectoring systems), in which case it brakes just the spinning wheel, forcing the power to flow to the other wheels. In any case, this electronical approach tends not to be quite so good as most mechanical ones, but better than some, so we'll keep going. The next most simple uses a locking center differential. This means normally the car has 3 open differentials, but when wheelspin is detected, or you push a button, the center differential locks, and now it works like 4 wheel drive with open differentials. This is actually pretty good. However it only really works if you're stopped. It can't safely engage while you're moving (or stuck, but with the wheels spinning). Part time all wheel drive means normally the rear wheels aren't connected to the engine at all, until they need to be. This is accomplished using a dry clutch (in which case it behaves like a locking center diff), or a wet clutch or viscious coupling. In the latter instances, the computer engages the rear driveshaft through the coupling, causing power to be sent back there. This is how most awd crossovers do it, like the crv. I'll save you some time and tell you it's generally garbage. With a wet clutch/viscous coupling, you've got regular, not brake based torque vectoring. Finally, you can have a limited slip or torsen limited slip center differential. This, I think, is the best bet for most people. Because of its mechanical nature you're not at the mercy of a computer programmed by someone who lives in the city and doesn't understand why people don't just take the train. It actually works. It's smoother, doesn't require any driver interaction or even driver attention, and it just works. Except torsen which might require you to apply a bit of brake. So the center differential is covered. Understand that every principle that can be applied to the center differential can also be applied to the front and rear differentials. In a perfect world, all three differentials would have computer controlled clutch packs capable of precisely sending a carefully selected amount of torque to each wheel. This is a thing in some cars. I believe it's the basis of acura's super handling awd (could be wrong, don't qu\u00f3te me on that) and the Nissan gtr and a select few other cars. In a next to ideal world all 3 differentials would be torsen or lsd type differentials. This is fairly common. In the worst case you'd have 3 open differentials. In the rear world, all wheel drive systems can be found that are pretty much every variation of this, many with different systems for each axle, but now that you understand what each does and how it works in the real world, you can make pretty informed decisions if you do your research first. Understand that all wheel drive and 4 wheel drive are blanket terms and in order to get anything that's actually useful, you have to understand the actual mechanicals underlying the marketing term. Edit: thanks for the gold. Also, none of you are actually 5 years old. I hope. There are boobs on here, so you shouldn't be. If you want an explanation that doesn't explain the difference between 4wd and Awd, read someone else's concise and misleading explanation. The reason I have to go into so much detail is that the differences between \"4WD\" and \"AWD\" are highly nuanced. Both are made up terms, and originally awd basically meant \"shitty 4wd,\" but thats not the case anymore. If I can type this on a blackberry, you can read it.", "Prettt simply put, AWD has a center differential which allows front and rear axles to rotate at different speeds. 4WD does not have this center diff so at all times 1 front and 1 rear wheel have to rotate at the same speed. Sometimes its how a manufacturer names it too. I know for a time at least the Jeep Cherokee could run in a full time 4WD mode which had an open center diff, putting it in part time 4WD mode would just lock that center diff.", "Different manufacturers and people use the terms differently, but in general: 4WD = off-road cars. The 4WD system can be turned on/off by the driver so the car is only driving two wheels normally, but engages the other two for difficult conditions. When engaged, the front and rear axles are connected mechanically - there's no (or little) provision for different wheel speeds as you would experience when taking a turn in the road. AWD = normal/sport cars. All four wheels are driven at all times, with a differential in between to allow \"slippage\" when taking turns. This is better for road use, but not as good for difficult terrain.", "This question is basically how to start a fight on auto/truck/offroad forums. While there's a consensus on 4WD, what function it provides and how's it's implemented, AWD is still not nearly as defined. Manufacturers will often implement it differently and the function is very different. Even to the point of implementing a Full-Time-4WD and then calling it AWD. You'll get 1 answer on 4WD and a dozen different answers for AWD.", "These days 4WD means you can switch between 2wd and 4wd. AWD you don't have a choice. As far as what wheels get torque and when - that is more a matter of what differentials you have in the front and rear axles. LSD (limited slip) will allow wheels to slip a bit in tight low speed cornering - this helps with not destroying your tires in parking lots for AWD and 4WD systems Locking differentials are a different beast and will actually force front or real axles to spin the wheels at the same rate and time.", "All-wheel drive is in some ways similar to the full-time 4WD system in that it also sends torque to all four wheels constantly. However, most modern AWD systems don't offer drivers the option to operate in two-wheel drive and, unlike the 4WD systems, the differential between the front and rear axles cannot be locked. [Source]( URL_0 )", "Finnaly something I'm an expert at. 4WD 4x4 and All wheel drive, if we're talking about a car, are all the same. This terminology just determines how many wheels can put power from the engine to the ground. AKA \"driving wheel\" Lets run a few examples to make it clear 1: If i have a regular motorcycle, it is 1 wheel drive. But if I get one of those Dakar modified bikes, that have 2 wheel drive, it will be simultaneously 2WD, AWD and 2x2. All possible wheels have \"power\" Now a modern four by four like the jeep renegade, it is on demand 4WD. Power goes to the front wheels all the time, and when needed also goes to the rear wheels. The vehicle has 2WD and 4WD modes. When in 4WD it is also in 4x4 and AWD. See where I'm going with this? It's just a matter of semantics. If you get what the words really mean in practice, that's it. All those terms tell you is how many wheels in the particular vehicle are capable of driving. Now, for the nitty gritty: Every manufacturer likes to call their traction systems a fancy name, like Subaru with their symetrical all wheel drive, or Land Rover with therir Terrain Response, or Jeep with Terrain Select. There are also many types of all wheel drive, or four wheel drive, or four by four... you get the point. I'll just call it AWD from now on. Older vehicles will be rear wheel drive, with the option to turn AWD on. Most modern \"common\" awd vehicles will be normally FWD and switch to AWD on the fly when needed. Some vehicles you need to switch by hand, at the wheel, others have electronic engagement, while others there's just a clutch that couples the secondary axle. The famous Land Rover Defender is what is called Full Time AWD, where the vehicle always sends power to all four wheels, you don't have the option of turning AWD off. For those cases, there's a third differential between the front and rear axles to compensate for the wheel speed difference between axles. Anybody that tells you AWD must do this, 4WD must do that, 4x4 must do that other thing, is just wrong and has no idea what they are talking about. Source: Am fourth generation mechanic. Also Mechatronic Engineer, and worked for one of the 5 biggest car manufactures in the world, in the AWD deppartament. TLDR: AWD 4WD are the same, if you are referring to a car. It just serves the purpose of conveying the information of how many wheels are capable of powering that particular vehicle. edit: Even people that work in this field are confused by the terminology. That's why the real question should be: What Kind of AWD or 4WD or 4x4 do you have/want/need. Not the difference between these terms. Even manufacturers use different terms to describe the same thing.", "4WD is typically selective (can be driven in 2WD or RWD) where AWD is always on. Typically 4WD uses a mechanical center differential with no slip (chain or gear drive) where AWD uses a viscous coupler (kind of like a wet clutch) where it can have some \u201cslip\u201d and direct power to front or rear as needed. Obviously very basic description but hope you get the idea.", "The difference is in the relationship between the front differential and the back differential. All-wheel drives usually have a horizontal differential that transfers torque to the axle with most resistance, making it better for driving on roads. In a 4Wd both axles are supplied with the same torque at all times, making it better for off-road.", "A truck that is capable of 4WD is usually a rear wheel drive vehicle for road driving until you lock the front diff. The front and rear diffs are usually locked harder than an AWD and will suffer on sealed surfaces for it. A Subarus diff (for instance) will have a baseline front and rear balance for power delivery. I.e. at 5% throttle it acts like a FWD, 20% throttle you'll get 10% of power to the rear wheels. When you floor it the distribution looks something like 60/40. The front and rear diffs are designed to be engaged at all times so can move to allow differential rotation. An AWD is supposed to be AWD at all times and is designed as such. A 4wd lets you choose how the powertrain operates based on your situation, and is not designed to be perpetually engaged. Hope that makes sense.", "If you have more than 4 wheels, then AWD > 4WD! :-) It's about traction distribution, AWD is a type of 4WD that is on all the time, so usually changes traction distribution according to what use you are giving it.", "While users like /u/krovek42 gave you a good technical description, understand that for some manufacturers, 4WD vs AWD is a marketing distinction, not a technical distinction. Ford uses 4WD when they market for off-road use and AWD when they market for all-weathr highway use. Let's look at the Escape and Edge: both use a front transaxle (FWD) equipped with a power take-off unit that connects to the rear driveshaft- > rear differential - > rear wheels. However, the Escape is marketed as 4WD since it still is marketed as a \"sport\" utility vehicle while the Edge is a crossover and gets an AWD designation.", "4WD= All the wheels get turn at same speed AWD=power can be split/directed between front and back.", "Generally speaking 4 Wheel drive sends equal amount of power at all times. All wheel drive is usually sending 80:20/70:30/60/40 to the front or back wheels. When the wheel recieving the most power starts to slip, the opposite end kicks in and the wheels are then divided at 50:50 until traction is regained, at which point it goes back to its original ratio.", "I'm starting to hate r/EIL5. AWD means the tires can move at different speeds based on road conditions. 4WD means all tires are spinning, but at the same speed. This is good off road but bad on road. That's how I'd explain it to a 5 year old.", "imagine if you had a car on a lift and tried to stop each wheel from moving: AWD: only one tire out of 4 moves 4WD: only one of the front and one of the rear moves There are different devices to change this, such as limited slip differentials, locking differentials, smart stuff like brakes helping.", "There's no official difference, but 4WD generally refers to a system designed to work best off of paved roads and AWD generally refers to a system designed to work on paved roads. AWD, like an Audi, puts the power to the wheels with the most grip, and 4WD, like a Jeep, locks the wheels so they always spin at the same speed.", "AWD is a marketing term originating with Subaru to differentiate its passenger car market from the larger 4WD market even though it\u2019s the same thing. Since then AWD has been appropriated by other manufacturers in their non-off-road offerings. From a technical perspective, there are, at its core, very few differences, however AWD systems used in passenger cars often include torque splitting technology to provide more or less power to front or rear wheels (and side to side). Ultimately AWD is used to market on road use passenger vehicles while 4WD is used to market vehicles with off road purposes.", "Edit: The top voted answer is now a better one. The top voted answer is incorrect, there is no difference. Just like there is no difference between a station wagon and an estate car. It's just two different names for the same thing. There are however many different versions of systems that drive on all four wheels and some are better than others for certain tasks. It's all a trade off between different use cases, price, weight, fuel economy etc. Nearly every car manufacturer puts a slight twist on their system and if you want to find what's best for you have to start learning about different types of all wheels drive systems and diffs etc.", "If the car has 4 wheels, and they all drive, we have both 4 wheel drive and all wheel drive. A few decades ago, most 4 wheel drive vehicles were offroad or utility vehicles, so the term \"4WD\" came to be associated with such vehicles. When 4WD on passenger cars was getting more popular, the marketing department had to invent a new term to dissociate themself from the image of the offroad trucks; and so \"AWD\" was born. So, the only \"difference\" is one of marketing, not of engineering or technical detail. Other answers mention different types of differential but that is a different topic really. You can have various types of differential in cars marketed as \"AWD\" and in vehicles marketed as \"4WD\"."], "text_urls": [[], ["https://youtu.be/yYAw79386WI", "https://youtu.be/xm8EHTTNPEg"], [], [], [], [], ["https://www.motoring.com.au/what-is-the-difference-between-4wd-and-awd-7530/"], [], [], [], [], [], [], [], [], [], [], [], [], [], []], "score": [12229, 11671, 468, 125, 111, 40, 34, 22, 13, 6, 6, 5, 5, 4, 4, 3, 3, 3, 3, 3, 3]}}, {"q_id": "7ivpiw", "category": "Repost", "title": "If we can see through water how come when snow is frozen its pure white?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dr1qr1b"], "text": ["Water and snow are structured differently in the same way that coal and diamonds are structures differently. In both scenarios, they are the same chemicals, but the orientation and layout of the chemicals changes their visual properties. In snow and coal, there is more space between the individual atoms, resulting in a greater surface area, which means there are more surfaces for light to hit and a lesser chance of light making it all the way through."], "text_urls": [[]], "score": [5]}}, {"q_id": "7iwaxj", "category": "Repost", "title": "Why are there so many types of screws? (Phillips, flathead, Allen, etc.) Why isn\u2019t there a single, standardized type of fastener?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dr1wbbl", "dr1wab7", "dr29pq2", "dr1zkbk", "dr21ch8", "dr1yxk2", "dr2a6ua", "dr1w4as", "dr2hjmy", "dr29i7y", "dr2hlu1", "dr2dqh3"], "text": ["As usual, there is a relevant XKCD... URL_0 Automod appeasement edit: At one point, there was only one type of screw. I'm no screwolologist, but it seems fair that the straight slot would've been that one type. Its ups were that it was easy to manufacture and it was easy to make a tool for it, but anybody who's used a straight-head knows it's a terrible, terrible screw head. So somebody set out to make a better one. I've no idea if I'm right, but I'm gonna guess it was a guy named Phillips. So he said, if one slot was ok, then two slots should be better! But anybody who's used a Phillips screw knows that they come with an appallingly low torque limit before you now have a conical-head screw that's impossible to do anything with. So somebody said straight heads suck, and phillips heads aren't much better, so I'll make one with some more meat in the tool and straight sides so rounding off and breaking tips wasn't such a concern. Thus, the Allen head was born. Except that allen/hex heads, below a certain size, are even easier to round out than Phillips heads were, and it's fucking impossible to get the hex key in there straight/to full depth in the fastener. So somebody said, that Allen guy was on the right track, but he didn't go far enough. So the Torx bit got invented. But then, people said that Torx was too complicated and it's impossible to tell the difference between a T25 and a T27 and oh my god why are there so many choices? So we went back to basics and saw if we couldn't improve on the Phillips design, which beyond its propensity to snap tips and round off fastener heads wasn't a *bad* design. So we got stuff like JIS, which is virtually identical to Phillips but designed to destroy your phillips bits, and Posidriv, which is the bane of my personal existence because they're designed to never, never strip while tightening (which they don't), but to always always strip immediately when removing (which they do). So that shit got real complicated and somebody said, guys, guys, you're making this too complicated, eh? What if we took an Allen, which is ok but has too small a load-bearing shoulder and too-great leverage angles, and simplified it, eh? And the Robertson (us Yanks call it a square bit) drive was born. And it was good. But somebody saw that the construction industry was using a messy hodgepodge of phillips and robertson screws and said, what if we combine them so construction people don't have to buy so many different bits? So now there's a combined R1/#2 phillips bit and screw. I guess that guy never got told about Torx bits, but hey, whatever. So now the construction industry is using an even messier hodgepodge of phillips, robertson, torx, and combi-drive bits. And then, electronics came along, and at some point electronics manufacturers decided that we lowly consumers couldn't be trusted/were too dumb to open their electronics, so anti-tamper bits had to be made, because everybody had tools to open the bits that were already around, for the most part. So they made those, starting with the Torx bits with the little posts in the middle, but it turns out those are pretty expensive to manufacture so they started making tri-wing screws, and those dove-tail head screws and the two-post screws and etc. etc. etc. because all the same shit that happened in the 10 paragraphs above happened in the anti-tamper-bit world all over again. Over time each industry sort of settled on certain screw type heads for certain applications, because as there was no \"perfect\" screw head each type had its strengths and weaknesses, and everybody is firmly entrenched in their own screw head system, and there is *very* little hope of ever unifying everybody, because there's a lot of money in it now. That doesn't stop people from trying, though - but since they don't understand the market dynamics and why there will never be such a thing as the one true screw head, all they do is just add yet another type to the mix, confusing everybody just that much more. Edit 2: well now my inbox is screwed, and it seems somebody has put an idea for a new screw head next to my name.", "In addition to Skatingraccoon's answer, many companies develop their own screws or other methods of attachment for their products to make it harder for the consumer to repair the item on their own. A proprietary screw needs a proprietary screwdriver, and if the company that makes the screw doesn't sell the driver, then it means people have to go to the company for repairs, which allows the company to charge them more than it actually costs to fix the product. Nowadays, smartphones are growing more and more proprietary, and the reason is so that it is more difficult to fix a damaged phone. With some of Apple's earlier iPhones you can see the unique shape of the screw: ( URL_0 ) Although apple did not create the 5-point screw, when they made the iPhone 4s they recognized that it was a very uncommon fastener, so they have used it to make their iPhones ever since. As the industry is racing towards thinner phones with larger screens and smaller bezels, some manufacturers have removed external screws altogether. The Google Pixel for example, has no screws on the outside. The Samsung Galaxy S7 Edge is another phone without visible screws. This is achieved by using an adhesive to fasten the screen to the frame, which saves space, and makes self-repairs much harder than before. That's just the relation to smartphones though, in construction and industry there are many other applications for unique screws. A little-known fact about screws is that screws with more vertices and angles in the bit design grip the driver better. For example, if you had a screw that had a bit shaped like an octopus, that would give the drill bit 9 points to transfer energy into the screw (8 legs and the head). If you had a screw with a bit shaped like a snowflake, it would be even better. The problem with forcing a lot of vertices into the design of the screw/bit is that it becomes easier to break the screw/bit, and the time/cost of production increases. That's why there are so many kinds of screws, so that consumers can choose the right one based on what they're doing and what their budget is. Hope this helped!", "Far more than you ever wanted to know: URL_0 Flathead screwdrivers suck, but they were something you could make with a hammer and anvil and forge. Philips (the real ones) were designed before power drivers with torque control were invented. There are a zillion modern designs to provide greater torque limits with reduced material (weight/space/size) that view standardization as an accomplice to theft. They are designed to be difficult to unscrew without the exactly correct driver, to deter theft.", "Some things that determine the type of a screw head: * How hard it is (or was) to manufacture * Patents and copyrights * industry inertia * what tools the installer or maintainer will have * Whether the screw will be installed by a robot * How much force does the screw have to withstand * How much of the screw head can stick out of the surface * The size of the screw * other environmental factors (expected corrosion, paint, hard to reach etc)", "Another angle people are not really covering. The world wasn\u2019t always as it is today. Transportation of products was far more difficult and expensive. Things like screws, bolts, and fasteners are fairly cheap to make. People making more complex items would either make these fasteners themselves, or get them from someone local. Now expand that idea across the entire world. With information and products being shared more everyday, there is less variation. However habit is a strong motivator. If my manufacturing process is working smoothly, why change? In all honestly is surprising there are not more variations. On a side note, this expands to many things. Recently I took a truck driving job. I found it really odd how many different warehouses, even by the same company, have totally different procedures in the way they do logistics. Unless I\u2019ve been to that exact warehouse before, I have no idea what policy\u2019s and procedures they will have. What makes things even more complicated is that everyone assumes that things are done the same everywhere, so there\u2019s an assumption I should know what to do. You\u2019d think there\u2019s one best way to do things, right?", "The first screws had a simple slit. When automation began, the Phillips screw was invented because it is self centering. The sides are angled, so if the first machines applied to much torque, they would slip rather than break. When machines got torque limiters, there was no need for angled sides. Pozidrive (pz) screws were developed. They only have small angled slits to make them slip should too much torque get applied. Later came hex and torx screws. They do not slip anymore, so the torque gets transferred completely and they break without efficient torque limiting.", "I know that each have their advantages and disadvantages in machining and construction, but specifically the \"Phillips\" head (AKA Cross-head) screw which is most common is often misused. 1. It has a notoriously low torque point, so it strips fairly easily. However, this is specifically needed with some industrial and automated applications, where engineers would rather have the screw strip at a certain torque applied by error rather than apply more torque and damage the item in question. 2. The Phillips is self-centering, so when an automated drill drive a screw in, all of the torque is evenly centered and distributed. Again, essential for some automated applications. So often the Phillips screw is used where higher torque would be helpful, but because of its availability and popularity it's often encountered in places where it's low torque become an unwelcome hassle. Not an engineer but that's the general point.", "It has to do with application. A simple flat head or Phillips is mostly used to just do a simple fastening. Allen is more for fastening with more torque, let's say you're going to machine a part and are fastening to a fixture, you would feel more comfortable using Allen set screws so your part doesn't bounce around. Some of the other screws are more rare so someone doesn't come along and unscrew anything.", "In short, because manufacturers and engineers are constantly improving and customizing products for their specific applications. Fasteners are the easiest thing to change when engineering a new product. It is easier to design a new fastener then scrap a good design because stock fasteners won't work. Thus, you have tons of different types of screws on the market. For a specific example, look at just machine screws. Originally, there were basically just slotted drive screws that you would drive with a Slotted or \"flat head\" screw drivers. The slotted driver would tend to slip out of the head so in the 1930's the Phillips screw and screw driver was invented. In both cases, they made a flat head for countersinking into the surface of a material, and a round head that stood proud of the material for use in hard materials that didn't easily countersink. Unfortunately, the Phillips drive can still slip and will tend to strip easily so at some point the Allen drive or internal hex drive was invented. That fastener was made with several head styles as well and was also made with a very strong alloy for high strength industrial applications. However, the internal hex drive can still strip in high torque applications so engineers improved on it with the development of the Torx drive (also called star drive, or six-lobe). As you can see, just the narrow application of machine threaded screws, we are already at dozens of combinations of heads and drives. Multiply that by several different materials that they can be made of (soft steel, alloy, stainless, brass), dozens platings and coatings, and dozens of different lengths for each combination and we have options in the thousands. Now there is a more recent issue of products being made with custom fasteners with obscure drives in order to make it harder for the consumer to service the items themselves. This is common in electronics and automotive applications. This has increased the number of different types of fasteners exponentially as well. Every type of bolt, wood screw, pin, and clip has gone through a similar progression and evolution.", "Tech companies (for example) want their products to be really difficult to disassemble so you have to pay them to get a repair if it breaks.", "When you're a robot or a human laying on your back with an automated driver and a fastener balanced on top of your bit, few things fit better than a 6-sized torx or perhaps a Robertson with shank. When you're a machinist and you have to countersink the bolt head in a smallish circular hole, Allens work best. This sometimes happens with complex whatsamajiggers that add another layer on top of the preexisting countersunk fastener. Phillips and slotted are legacy products.", "Essentially for all the screw head types, you can make a statement like \"straight screw heads are easy to manufacture, but with power tools there is a strong tendency for the bit to slip out of the slot and mar the work surface.\" or \"Philips heads won't slip out under power and will cam out rather than over tighten, but they will strip easily making it difficult to remove. You have to push in while screwing out.\" or \"Robinson heads won't slip out, won't strip, and work well with a tortion clutch to prevent ovdrtightening. Too bad Robinson was stingy with his patents so no one supports his screw heads outside of Canada\", or similar \"this screw head is good for these reasons, but is bad for these other reasons.\" Picking one standard would work well for some things, but not others."], "text_urls": [["https://xkcd.com/927/"], ["https://goo.gl/images/sTQqgN"], ["http://www.instructables.com/id/When-a-Phillips-is-not-a-Phillips/"], [], [], [], [], [], [], [], [], []], "score": [7565, 97, 96, 39, 34, 21, 7, 6, 4, 3, 3, 3]}}, {"q_id": "7j0m1h", "category": "Repost", "title": "How do antidepressants work in the human brain?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dr2rwaa"], "text": ["I'll just touch on the most common type of antidepressant, which are SSRIs, or \"selective serotonin reuptake inhibitors.\" Serotonin is a chemical transmitter that we understand to be important for regulating mood and other \"higher\" functions. It's released from neurons in certain parts of the brain, where it binds to neurons elsewhere and tells them to do things. Without getting too complicated, this brain activity helps make us feel \"normal,\" or not depressed. People with depression tend to have low stores of serotonin to release, or don't release as much as they should. The purpose of an SSRI is to make that available serotonin last longer. Naturally, the brain recovers serotonin that's been released, and recycles it for later. As the name implies, a \"reuptake inhibitor\" will stop the brain from recovering that serotonin, so it has more time to float around and do its job. **True ELI5 Answer:** If you imagine serotonin as kids running around being happy in a playground, SSRIs are equivalent to giving them snacks and water so they can play all day. That, or like slashing their parent's tires so they literally can't leave."], "text_urls": [[]], "score": [7]}}, {"q_id": "7j6mry", "category": "Repost", "title": "Why are female breasts and boobs seen as so 'inappropriate' even if the woman if breastfeeding, but things much more out of the ordinary such as dismembered limbs and torture are PG13?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dr40knk"], "text": ["Ahoy, matey! Yer not alone in askin', and kind strangers have explained: 1. [ELI5: Why is porn more censored than violence ? ]( URL_5 ) ^(_9 comments_) 1. [ELI5: Why is Violence more tolerable than Sex in America? ]( URL_6 ) ^(_ > 100 comments_) 1. [ELI5: In movies, why is excessive violence/blood OK, but sexuality off-limits? ]( URL_3 ) ^(_19 comments_) 1. [Why is violence considered acceptable to show on american television but anything sexual isn't? ]( URL_7 ) ^(_5 comments_) 1. [ELI5: Why is violence more acceptable than nudity or sexual content in media? ]( URL_2 ) ^(_60 comments_) 1. [ELI5: Why is it appropriate for PG13 movies/shows to display extreme violence (such as mass murder, shootouts), but not appropriate to display any form of sexual affection (nudity, sex etc.)? ]( URL_1 ) ^(_ > 100 comments_) 1. [ELI5: Why do we shield children from sexual content, but not violent content? ]( URL_0 ) ^(_74 comments_) 1. [ELI5:Why are parents so afraid of nudity or sexual content? ]( URL_4 ) ^(_7 comments_)"], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/1yahp4/eli5_why_do_we_shield_children_from_sexual/", "https://www.reddit.com/r/explainlikeimfive/comments/5uhr0x/eli5_why_is_it_appropriate_for_pg13_moviesshows/", "https://www.reddit.com/r/explainlikeimfive/comments/34pg6o/eli5_why_is_violence_more_acceptable_than_nudity/", "https://www.reddit.com/r/explainlikeimfive/comments/30arpa/eli5_in_movies_why_is_excessive_violenceblood_ok/", "https://www.reddit.com/r/explainlikeimfive/comments/3zz2a4/eli5why_are_parents_so_afraid_of_nudity_or_sexual/", "https://www.reddit.com/r/explainlikeimfive/comments/zk37g/eli5_why_is_porn_more_censored_than_violence/", "https://www.reddit.com/r/explainlikeimfive/comments/3q25bp/eli5_why_is_violence_more_tolerable_than_sex_in/", "https://www.reddit.com/r/NoStupidQuestions/comments/7e40cy/why_is_violence_considered_acceptable_to_show_on/"]], "score": [4]}}, {"q_id": "7j9st6", "category": "Repost", "title": "How and why exactly does anxiety affect your whole body? (eg. digestive system, feeling cold, etc)", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dr4otxx", "dr4pjw0"], "text": ["Stress causes your adrenal glands to release adrenaline which causes a wide range of physical symptoms.", "Anxiety evolved to deal with threats, so the body can respond accordingly. A lot of the physical symptoms are related to the hormones released to prepare your body to fight or flee. The reason you get digestive symptoms is because the hormones restrict blood flow to your digestive system, so there is more blood available for your muscles and other organs to use. Feeling cold is explained by blood vessels near your skin constricting to divert more blood to muscles and other important organs."], "text_urls": [[], []], "score": [17, 14]}}, {"q_id": "7jjl9r", "category": "Repost", "title": "How did gold and silver became the currency in ancient civilizations even why they didn't have any practical use?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dr6u990", "dr6sod4"], "text": ["You could hardly find a better metal than gold to serve as a low tech money. * It's rare enough to be valuable in small amounts (so a man can carry enough to facilitate almost any transaction). Also it's almost always found in high purity forms. * It's soft/malleable enough to be easily made into change on the spot. * It's dense enough that it's very hard to counterfeit and easy to verify the density with two vessels, a balance, and some water. * It's almost totally incorruptible, so if you hide away some gold, you can be assured that it will be in the same amount and form when you find it (presuming no one stole it from your hiding place). [This is gold]( URL_0 ) that's been sitting at the bottom of the ocean for thousands of years, while some other stuff has accumulated, the gold is unchanged. It's quite hard to find any other objects that meet all those specifications.", "No practical use? Gold and silver are noble metals-that is they resist corrosion. Silver does slowly tarnish, but because of the long lasting beauty of these metals, they have always been valued. And since they don't degrade, they make good stores of value over time."], "text_urls": [["http://images.nationalgeographic.com/wpf/media-live/photos/000/185/cache/bronze-age-shipwreck-curtsinger_18502_600x450.jpg"], []], "score": [9, 5]}}, {"q_id": "7jks54", "category": "Repost", "title": "what makes the sound of my tummy rumbling when I'm hungry?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dr73fj9", "dr7c98p"], "text": ["Your stomach always rumbles, it's just loader when it's empty. Imagine having a bongo and stuffing it full of towels, it would sound muffled and wouldn't be very loud. Now take them out, and give it a bash, it is now loud and actually makes a sound.", "Borborygmus (the medical term for that rumbling in your stomach) is caused by peristalsis acting on the contents of your intestinal tract. Peristalsis is a constant series of waves of contraction that move the contents along towards the exit. It's like putting your fingers around one end of a ketchup packet and running them towards the open end to get the ketchup onto your fries. Your gastrointestinal tract always has solids, liquids, and gases in it. As the wave of contraction moves along the tract, this stuff gets mashed together and moved along, making the noises you here."], "text_urls": [[], []], "score": [5, 3]}}, {"q_id": "7jnnxq", "category": "Repost", "title": "How do mathematicians actually go about calculating the digits of pi or of other infinite, non repeating numbers like e?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dr7r3ga", "dr7wgl4"], "text": ["For most of these numbers there are some equations, series, sums or other 'simple' methods for calculating the number to any desired precision. For instance one of the first definitions of e was e = (1 + 1/n)^n as n approaches infinity. So if you want to approximate e just plug in any number instead of n. The larger number you pick, the closer your calculation will be to e. For Pi there are so many sums that slowly tent towards pi that it's quite ridiculous. [Wolfram Alpha has a very large page explaining the most common formulas]( URL_0 ). They'll tend towards pi at different rates, but they'll eventually get closer and closer. Pi also has a fun algorithm that can be used to calculate any arbitrary digit of pi, which is handy if for some reason you wish to *only* calculate the 50013rd digit of Pi for some reason. And so on and so forth. For most irrational constants that have names and well defined values there are also some methods to approximate those values.", "They prove that a particular infinite series converges to pi, then simply compute enough terms of that series to get the digits they are looking for out of pi. For example: pi = 4 - 4/3 +4/5 - 4/7 + 4/9 ... All you have to do is keep computing terms and you can get whatever degree of accuracy you wish. That particular series is kind of terrible and converges very slow, but more complicated once converge more quickly."], "text_urls": [["http://mathworld.wolfram.com/PiFormulas.html"], []], "score": [7, 3]}}, {"q_id": "7jr7e7", "category": "Repost", "title": "What causes heat tolerance differences between people?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dr8iqbe"], "text": ["So many different things. Amount of muscle and fat, overall size, skin density and sensitivity, size and distribution of sweat glands, simple preference. Women tend to get cold faster than men because their network of blood vessels is denser in their core, causing lower blood flow to extremities like fingers and toes."], "text_urls": [[]], "score": [7]}}, {"q_id": "7jrrda", "category": "Repost", "title": "Why does repeating a word or phrase over and over make it lose meaning in your brain?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dr8oq0i", "dr8oinz"], "text": ["It\u2019s a phenomenon known as Semantic Satiation. It\u2019s just as you describe; one will say a phrase or word so many times that it eventually temporarily loses its meaning. Interestingly enough, there\u2019s also a phenomenon where if you engage in Semantic Satiation, doing the task at hand will become slightly more difficult. URL_0 Edit: There\u2019s a more so \u201cexplain like I\u2019m an adult\u201d explanation on the phenomenon where tasks become more difficult if you verbally repeat them, but I couldn\u2019t find much (on the cellular or neurological level) as to why Semantic Satiation in specific occurs.", "words only have meaning when you use them with other words... so by using it improperly over and over (repeating it nonsensically), your brain eventually begins to believe it really means nothing."], "text_urls": [["https://en.m.wikipedia.org/wiki/Semantic_satiation"], []], "score": [14, 10]}}, {"q_id": "7jt3w0", "category": "Repost", "title": "Why do headphone wires get entangled?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dr8zjgt"], "text": ["Entropy, there's only one way for them to be untangled but billions of ways for them to be all tangled up. Any change of state, say they get jostled or moved about will statistically lead them to be tangled as opposed to untangled."], "text_urls": [[]], "score": [5]}}, {"q_id": "7jy6zy", "category": "Repost", "title": "Why do we get that sharp ringing noise in our ears out of nowhere?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dra42ty"], "text": ["this is called sudden brief unilateral tapering tinnitus...a temporary loud ringing in one ear that after around a minute or so tapers off into nothing. also known as an sbutt :) not much is known about what causes them, but it seems around 3/4 of everybody has had at least one episode, and that having it in the right ear is about twice as common as in the left. there seems to be a loose correlation with regular tinnitus, with people who have tinnitus being more likely to have sbutts, and people who have a lot of sbutts are likely to have or develop tinnitus. all in all, there doesn't seem to be any hearing loss associated with the occasional sbutt."], "text_urls": [[]], "score": [37]}}, {"q_id": "7jymvg", "category": "Repost", "title": "Where does the giant amount of money out of the 21 century fox purchase by Disney go to?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dra6hrc"], "text": ["It goes to the current owners. Since 21st Century Fox is a publicly listed company, anyone can own shares of the company - you or me, for example. I suspect that most of the company is owned by things like pension funds. Most of the payment will be made in the form of shares, rather than cash. According to the [Financial Times]( URL_0 ), current shareholders will each receive 27.4 cents worth of Disney shares per Fox share they own, and at the end of the transaction they will own 25% of the new, combined company."], "text_urls": [["https://www.ft.com/content/c9635a99-8be6-33ed-9711-beb8c5bcc177"]], "score": [7]}}, {"q_id": "7k0fw2", "category": "Repost", "title": "Why are perfume ads all uniformly bizarre?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drajm11", "dral0ka"], "text": ["Short answer: because they can't use the TV to show what the stuff smells like. Long answer: because they want to make sure that the brand is cemented into your mind in a slightly positive way, so they flood the senses with imagery related to sexuality, pleasant activity, and intrigue, which gets you to remember their version of toilet water above others.", "We all know what brand of batteries uses an annoying bunny in their ads, we all know which burger chain has a redhead clown in their ads. The thing is all batteries are pretty much the same package of chemicals and a burger is a burger so the more your product is the same as your competition's the more you have to advertise it and use ads that in some way stand out. All perfumes are solutions of smelly things in alcohol so they have to put a lot of effort into making you remember their brand when you decide to find out what it smells like, which they can't possibly communicate in advertising."], "text_urls": [[], []], "score": [43, 5]}}, {"q_id": "7k0rau", "category": "Repost", "title": "Why are images in infinite mirrors turning greener after each level?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drb0ds4", "dramtmd", "dramuhr"], "text": ["Even truly tiny amounts of iron will tint glass a greenish color. So the green color in mirrors is a result of the glass itself being not totally colorless. Note that other elements will lend different colors to glass, cobalt produces an unmistakable ocean blue and cadmium sulfide produces yellow. Now, since iron is the fourth most common element in earth's crust, and considering that the basic raw materials for glass are bulk minerals like sand and limestone, getting traces of iron out of glass is exceptionally difficult. Nevertheless for things like optical fibers it's important to get high clarity and for that all traces of impurities need to be removed. This is typically done by converting raw silica sand into silicon tetrachloride (SiCl4) which has a low boiling point, then distilling it several times. Then finally the SiCl4 is reacted with water vapor producing ultrapure silicon dioxide. In cheaper grades of glass, such as those used to make bottles, the greenish tint tends to be more obvious. Extra iron salts may be added to make dark green wine bottles. This helps absorb UV light which can degrade wines.", "Class is not perfectly clear. Nor is the color of the reflection a perfect reproduction. Over many interations you're seeing the slight color variation from the glass stack up over and over.", "The glass used in mirrors is greenish. Normally it's too thin to notice, but after a reflection has passed through the glass pane thirty times you're now effectively seeing several inches of glass instead of 1/8\"."], "text_urls": [[], [], []], "score": [9, 6, 5]}}, {"q_id": "7k0z7k", "category": "Repost", "title": "Why do we experience brainfreezes when we consume cold drinks too fast?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drap78x"], "text": ["Brainfreeze is caused by your nerves not being totally connected in obvious paths. The trigeminal nerve serves the forehead as well as the roof of the mouth. The brain processes \"too hot\" signals from the roof of the mouth correctly, if you sip a hot beverage. Alas, \"too cold\" signals get mistaken for \"bumped head\" signals because these nerves are a party line. The real term for brain freeze is sphenopalatine ganglioneuralgia (meaning \"pain of the sphenopalatine ganglion\"), and we're not going to switch to that any day soon."], "text_urls": [[]], "score": [3]}}, {"q_id": "7k11rz", "category": "Repost", "title": "Why does tubberware never dry properly in the dishwasher?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["draoq68", "draoxsy"], "text": ["Plastic doesn't conduct heat as well as porcelain or glass does, so the water isn't able to evaporate from the plastic due to the lower temperature of the material.", "Plastic dumps it's heat way faster than glass and ceramic because it's far less dense, thus the water doesn't dry off. and this topic comes up a lot in ELI5."], "text_urls": [[], []], "score": [8, 4]}}, {"q_id": "7k6a4l", "category": "Repost", "title": "what causes the pins and needles sensation when a body part falls asleep?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drbx76i"], "text": ["It's actually usually pressure on the nerve, not blood vessels. Basically, when you press on the nerve, it makes it fire extra signals which confuses your brain. It takes a little bit after the pressure is released for everything to readjust back to normal."], "text_urls": [[]], "score": [5]}}, {"q_id": "7k6ayo", "category": "Repost", "title": "Could a person get access to the internet without an ISP? How much money and equipment would it take to connect to the internet by yourself?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drbvxxg"], "text": ["Your ISP is very much like the post office, it helps you send and receive packages of data (packets) between you and your destination (a server). So, along these lines you are asking the question of \u201chow can a person get mail without a post office?\u201d Well, he would have to create his own post office. You will find very quickly that you end up right back with the same system you were trying to get rid of. In reality you would have to recreate the massive infrastructure that Verizon, Comcast, and the rest have collectively spent trillions on in the past 100 years. It\u2019s just extraordinarily prohibitively expensive."], "text_urls": [[]], "score": [3]}}, {"q_id": "7k6mhq", "category": "Repost", "title": "why do some things stick together while other things do not", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drbyqgr"], "text": ["You are staring at the fact that different substances are, well, different. Water is wet. Dry sand is dry. Wet sand can be shaped. If you carefully shape wet sand with a hollow in it you can pour liquid metal into the hollow. When it cools you have a shaped tool. If you are in a subway car and the next car is full of zombies you can wet newspaper and put it over the windows. In that movie zombies did not try to attack you if they could not see you. They were calmer. Atoms have nuclei, very small regions where protons and neutrons are assembled. It took a lot of energy to get them together. But once together they mostly stayed together if the combinations was stable. Most combinations are not stable and will fly apart. So we see the survivors, the combinations which are much more stable than other combinations. Being stable, that is being able to stay together for a long time, often the length of the universe, means the long range effects of stable nuclei show up. Nuclei have a positive charge. No electrons allowed in. But they are attracted to nuclei until they bump up against the strong force which keeps them away. That is why it took a lot of energy to form the nuclei, the strong force keeping things away. Instead of joining the positive forces in the nuclei the electrons will occupy orbitals around nuclei. Generally the most stable configuration is a number of electrons matching the number of protons in the nucleus. Electrons generally stay away from each other. They have the same charge. But two of them can stay closer if they have an opposite characteristic unfortunately called \"spin.\" This spin is not what pool balls, basketballs, or any other balls do when spinning. But the name was thought up and it stuck. Maybe this quality should be renamed. But it is hard enough to visualize things at an atomic level. Electrons are not really little balls, nor do they actually spin, probably. They do exist. They have properties. One is called spin. That is the way it is. Electrons dance around in the area around nuclei. While they dance they arrange themselves into pairs and singlets. They change energy states giving off or absorbing photons. Electrons at the outer edge of these areas called orbitals interact with the rest of the universe. They may actually be in a position between two or more nuclei. They will be occupying something like an orbital, an orbital far more complex than the simple ones close to nuclei, but they are at an energy state less energetic than a free roaming electron. They gave off a photon. They interact far less with the universe. Theoretically free roaming electrons can respond to other electrons and protons very far away. It can be confusing. But these interactions mean some things are sticky while others are less sticky. It is the electrons in the outer cloud of electrons surrounding the nuclei which determine if something is sticky. If the nuclei have an odd number of protons then and odd number of electrons, a number matching the number of protons, surround the nucleus. The electrons between two or more nuclei will tend to stay there if they help balance the electrical charges. But they can move. So when you move two substances together they either stick, or they do not."], "text_urls": [[]], "score": [3]}}, {"q_id": "7k6sxh", "category": "Repost", "title": "Where do we get oxygen from during winter?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drbyqkw"], "text": ["Most of the world's oxygen comes from the ocean. About 70% actually. And it isn't winter everywhere at the same time, in fact it's pretty much always winter equally globally. The southern hemisphere is actually in Summer right now. Perks of living on a big wet ball, things are pretty much always balanced out"], "text_urls": [[]], "score": [13]}}, {"q_id": "7k70i0", "category": "Repost", "title": "Why can you become ill from eating chicken that\u2019s undercooked, but you don\u2019t from other meats, like beef?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drc0es9"], "text": ["First, you're not quite fully correct. You can easily get sick from eating other undercooked meat. Happens all the time in places where there's not the greatest sanitation or proper handling processes. Different meat animals are raised and handled under different circumstances, and then prepared in different ways. Different types of organisms live in, on and around them before and during their processing as well. A lot of chickens pretty much wallow in their own filth, for example, and so there's all sorts of possible sources of Salmonella bacteria when someone mishandles them. Fully cooking chicken kills the bacteria and removes the problem. And some food poisoning sources like the trichinosis roundworm live more with one type of animals than others, and so you're instructed to cook pork thoroughly to avoid that one. You're still taking a chance when you eat blue or rare beef, but usually it's prepared in a way that minimizes its exposure to surfaces, and people usually sear its outside where the bacteria might accumulate. Not quite as true with ground beef though - grinding it exposes a tremendous new surface area to your appliances... and that's why 'medium' hamburger or \"steak tartare\" are not served in a lot of restaurants as a way to reduce the chances of food poisoning."], "text_urls": [[]], "score": [9]}}, {"q_id": "7k8mp1", "category": "Repost", "title": "How do fishes gills work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drcekfm"], "text": ["Ahoy, matey! Yer not alone in askin', and kind strangers have explained: 1. [ELI5: How do fish gills work? ]( URL_5 ) ^(_6 comments_) 1. [ELI5: How do fish gills actually work? ]( URL_1 ) ^(_11 comments_) 1. [ELI5: How do fish gills work? ]( URL_7 ) ^(_7 comments_) 1. [ELI5: How do gills work, and why can't fish survive on land very long? ]( URL_0 ) ^(_2 comments_) 1. [ELI5: how do the gills on a fish filter out the oxygen from the water? ]( URL_6 ) ^(_40 comments_) 1. [ELI5: Do we know how do gills work? If we do, what is stopping us from designing fake gills that you can simply put into your mouth or up your nostrils? ]( URL_8 ) ^(_4 comments_) 1. [ELI5 What do gills do? Why do fish need oxygen in water but can't breathe air? ]( URL_2 ) ^(_5 comments_) 1. [ELI5: Why fish can pull oxygen from the water yet not from the air. ]( URL_3 ) ^(_11 comments_) 1. [ELI5: How do fish \"breathe\" water? ]( URL_4 ) ^(_6 comments_)"], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/631c3s/eli5_how_do_gills_work_and_why_cant_fish_survive/", "https://www.reddit.com/r/explainlikeimfive/comments/5cdaul/eli5_how_do_fish_gills_actually_work/", "https://www.reddit.com/r/explainlikeimfive/comments/1uaym8/eli5_what_do_gills_do_why_do_fish_need_oxygen_in/", "https://www.reddit.com/r/explainlikeimfive/comments/m0gkq/eli5_why_fish_can_pull_oxygen_from_the_water_yet/", "https://www.reddit.com/r/explainlikeimfive/comments/3v8xq8/eli5_how_do_fish_breathe_water/", "https://www.reddit.com/r/explainlikeimfive/comments/63ek5q/eli5_how_do_fish_gills_work/", "https://www.reddit.com/r/explainlikeimfive/comments/3nowet/eli5_how_do_the_gills_on_a_fish_filter_out_the/", "https://www.reddit.com/r/explainlikeimfive/comments/1qf7e9/eli5_how_do_fish_gills_work/", "https://www.reddit.com/r/explainlikeimfive/comments/1rdat5/eli5_do_we_know_how_do_gills_work_if_we_do_what/"]], "score": [7]}}, {"q_id": "7k991o", "category": "Repost", "title": "How can some things look worse or better in real life than in a photo/video, for example the saying that 'the camera adds ten pounds'?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drchynl", "drcjuqc", "drckqsp"], "text": ["The specific lens a camera uses distorts light. Likewise, certain lighting can make a major difference, as can the angle at which a photo is taken. All of these factors mean that a photo can make something look much better or worse than it normally does, by manipulating those factors.", "I think a lens can certainly play a factor but I think there are probably some other things at play even if lens distortion is at a minimum. For example they are seeing themselves at an angle different from what they are used to seeing in the mirror. Their posture could be different and the lighting could be more or less flattering.", "The process that turns a real life object to a picture is full of distortions. To start with the light's path to the sensor: Each lens distorts the incoming light with in a handfull of ways. This can only be partly corrected by adding more lenses. In digital cameras, light is maped to 3 colors: red green and blue (RGB), which match the corresponding photoreceptor cells in the human eye. Although it is impossible to to build a sensor that matches the exact wavelengths and dynamic range of the human eye which varies between individuals. Corrections can be made with digital image processing. The output is then stored in a file which again uses RGB to represent a color. Which are again displayd with RGB dots on a digital monitor. Given the theory of the CIE 1931color space, 3 colors are unable to cover the entire spectrum of the eye, so a digital picture will never look like its real life counterpart. TV display manufacturers try to improove vibrance by adding a fourth color e.g. yellow."], "text_urls": [[], [], []], "score": [10, 4, 3]}}, {"q_id": "7kcbxm", "category": "Repost", "title": "Why is that when something spins fast in one direction, it looks like it's spinning in the other direction?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drd8r7b"], "text": ["Your brain processes imagery at a certain rate; how fast the rate actually is depends in many things such as whether something moves in the center of your vision or at the edge, the motion in question, the colors and lighting evolved, your choice psychological state, etc. For the sake of argument, let's assume our eyes capture a visual snapshot 100 times per second and send it to the brain for processing. If something like the rotor blades of a helicopter was to spin at 100 revolutions per second, the blades would appear to stand still in mid air, as your eyes catch them in the same position each time. But what if they turned at only 95 revolutions per second? Each time your eyes send a snapshot, the blades would almost have reached their previous position, but not quite. And here's the trick: your mind actually interprets this as the blades having moved backwards as it never got to see the intermediate states. Add this up over many snapshots and a rotating object will appear to spin backwards at certain speeds."], "text_urls": [[]], "score": [8]}}, {"q_id": "7kd0hg", "category": "Repost", "title": "Where do ISPs get their 'internet'?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drddo2v", "drdd5wp", "drdd3wz", "drdf16y"], "text": ["Consumer level isp's get their upstream connection from backbone isp's. Backbone isp's lay down wire that connect regional or cross country and international cross ocean. Backbone isp's are like level3, CenturyLink, cogent. If you run a tracert command to somewhere like Europe or Asia, you'll see these names pop up.", "ISPs are like roads with toll booths. The internet is a network of roads. The stuff you want is the trucks and cars that travel on the roads; the ISPs (roads) don't *make* the content, they only delivery it from point a to point b. If you want your own isp you need to be able to put in the money up front to make a whole bunch of roads, including putting in wires to individual houses and providing the modems & routers they need, and then connect their traffic to the larger backbone infrastructure of networks.", "At that level it doesnt really work like that, there is no \"central clearinghouse\" ISP's have routers (not dissimilar to your router at home, but way way bigger and with loads more interfaces) They also have cables that connect them to other ISP's instead of one up link these core routers have different links to different networks (other ISP's) and a routing table ( URL_0 ) to make sense of what ip's are reachable, and via what distance sometimes traffic for a single IP will traverse several different \"ISP's\" networks before getting to its destination IP Hosting firms (that own data centers) just count as thier own ISP's in this model", "> I know that the internet is made up of servers that are inter connected and you can instruct your browser to access certain servers, and that all ISPs do is provide the wiring to connect these servers to your house but where does it all meet up? If I were to start my own ISP, how do I set up my service to be able to connect everywhere else? A wholesale internet for want of a better term. Thanks. Your question is sort of asking where all the roads in your country meet up, which doesn't really make sense, considering how many roads there are. If you were to start your own ISP, you might connect to another Internet service provider, say Level3, which have routers that have connections to other ISPs and whatnot. The road analogy is pretty good here, as it is pretty much the same thing. You just need to connect your road or set of roads to some other set of roads with connections to everywhere else. You may want to look at [this AMA post]( URL_0 ) about someone who set up a rural wireless ISP that launches in January."], "text_urls": [[], [], ["https://en.wikipedia.org/wiki/Routing_table"], ["https://www.reddit.com/r/IAmA/comments/7etu6x/iama_guy_who_setup_a_lowlatency_rural_wireless/"]], "score": [3, 3, 3, 3]}}, {"q_id": "7kemv3", "category": "Repost", "title": "Why does Coke taste different out of Glass, Plastic or Aluminium?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drdog9e", "drdohzq"], "text": ["Cans contain lining material that may or may not absorb flavor, plastic bottles have chemicals that can migrate (in very minute amounts) into the soda, glass bottles are inert and only really affected by light contamination and temperature changers. Though I find the difference almost non-existent from an objective standpoint when it's poured into a glass. Drinking directly from a can I can tell the difference though b.c. I can taste the aluminium. That all being said, I do think glass bottle coke is better than canned or plastic bottled. Ha", "Different environments make the same food taste different. * wine in different glasses. URL_0 * food on an airplane URL_1"], "text_urls": [[], ["http://www.sciencedirect.com/science/article/pii/S0195666303000825", "http://www.bbc.com/future/story/20150112-why-in-flight-food-tastes-weird"]], "score": [6, 3]}}, {"q_id": "7kh9mg", "category": "Repost", "title": "What are memories? How do they happen? How are they stored? Why do they fade?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dredr16"], "text": ["Imagine you're building a tiny robot. It's incredibly primitive. About the size of a marble. With tiny wires, legs, and the smallest of circuits that can only remember very basic commands. Mostly it just sort of wanders aimlessly around until it bumps into energy, which is uses as food. Or perhaps other robots. Which they dissemble for food, if that other robot can't run or fight them off. This tiny robot can make more of itself though (if it finds sufficient materials). But the catch is...every time it does, the new one has minuscule, *almost* random changes AND the robots existing adaptions might be passed down to it's \"offspring\". Before long you have tens of thousands of tiny robots. Most of these changes are entirely neutral. But some of them are actually useful - such as improvements to locomotion, new ways of detecting food, or running away from aggressive robots. Conversely, the adaptions that are less useful start to die off as they make it harder for a robot to exist. Given sufficient time, you'll see an amazing menagerie of fantastic robot designs. Some will remain the size of marbles, but some will gradually become bigger! Some of them will smooth their legs over many generations to become wheels, and zip around speedily and efficiently. Some will get larger, or even armored, to dissuade predator robots. Some might get bigger circuit boards to accommodate more chips and wires. Now, one of these robots has an interesting adaption with it's enlarged circuit board adaption. It is able to *remember* things. It has a very primitive temporary storage system that lets it remember food locations. One location at a time. And this gives it a survival advantage over other robots that are just floating aimlessly. This in turn leads to offspring with this advantage, who expand that storage system further so it can remember two things at a time. And then again. And again. The storage space gets bigger, the circuit gets bigger, but it's still a really primitive system build on an ancient way of remembering where food is. And that system is prone to error, data loss and misinterpretation. No matter how many robot generations you observe, that memory system is never going to be perfect because it's a steady gradient of alterations on a primitive system. With no overarching goal and no intelligence watching over it. The only thing deciding whether or not the adaption is an improvement is whether it works *well-enough to not get you killed* and well enough to get you to breeding age. Perfection isn't important. On the other side of the coin, take hard drives. Where an intelligent designer has gone *\"right, we need this data stored and retrieved perfectly. How do we achieve this\"*. Then selected specific piece of technology to do it (Magnetic Disk), provided all the necessary parts, tested it a thousand times, then manufactured it. The system is designed for it's intended role, right from the get-go. **TL;DR** - Our \"memories\" are just sensations stored by our food locating/survival system contained inside our skulls. And said recollections are stored and retrieved imperfectly because the system that designed it (evolution) did not reward perfection. Only what works \"well enough.\""], "text_urls": [[]], "score": [4]}}, {"q_id": "7kjvhx", "category": "Repost", "title": "How do Phone Scammers Spoof Their Caller ID?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dreybv1"], "text": ["Many are using VOIP programs that mimic calls, but use a computer instead of a phone. This bypasses the need for a phone service plan, the number can be changed at any time, and no Caller ID in the world would accurately judge where the call was coming from. These are lovely benefits to someone who wants to make a whole lot of spam calls in a short period of time, because the computer can make many calls simultaneously while a phone can really only do one."], "text_urls": [[]], "score": [6]}}, {"q_id": "7kjyy5", "category": "Repost", "title": "why are keyboards 'qwerty' and not alphabetical?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dreyl6n", "dreya0k"], "text": ["We don't use all the keys with similar frequency while typing. In English ETA are the most used alphabets so ETA are pressed more times than other letters. In the past age of mechanical keyboards and typewriters, when two keys which are next to each other are pressed it caused typewriters to jam To prevent this the most used letters are placed far and requires one to alternate hands which reduced jamming of the keys and lesser used keys(like X) are placed at tricky positions which are not so easy to reach. Other keyboard layouts also exists like Dvorak and workman which are suitable for typing in other languages than English. **ALSO** Contrary to the popular belief QWERTY layout was not designed to slow the typist but rather to speed up typing by reducing jams and alternating hands(which is a desirable trait for good speed).", "The arrangement of characters on a QWERTY keyboard was designed in 1868 by Christopher Sholes, the inventor of the typewriter. According to popular myth, Sholes arranged the keys in their odd fashion to prevent jamming on mechanical typewriters by separating commonly used letter combinations."], "text_urls": [[], []], "score": [9, 8]}}, {"q_id": "7kks14", "category": "Repost", "title": "Why does pouring salt on snow or ice make it melt?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drf32pd"], "text": ["It lowers it's freezing point. So you were right. A 10-percent salt solution freezes at 20 F (-6 C), and a 20-percent solution freezes at 2 F (-16 C). Even in snow there is small amount of liquid water. Salt dissolves there and starts to \"spread\". You can try this yourself with a ice cube and a pinch of salt."], "text_urls": [[]], "score": [4]}}, {"q_id": "7kq461", "category": "Repost", "title": "How do Anti Virus programs work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drgb7on"], "text": ["Most anti-virus software uses a combination of techniques. One is comparing a file or program on your system to its definitions database, a collection of files/programs that are known to be or install malware. The second is \"heuristics\" - basically algorithms and profiles it applies to files and programs on your computer to determine how likely something is to be malware. If something is a certain percentage of a match, it gets quarantined and flagged for deletion. In the terms of cops 'n' robbers (apologies for the not so politically correct analogy)... The first one would be like taking a suspect's fingerprints and seeing they're wanted for a crime. The second would be like police profiling/stereotyping of suspected drug dealers in certain neighborhoods."], "text_urls": [[]], "score": [11]}}, {"q_id": "7kqvxa", "category": "Repost", "title": "Why cookies get soft when there is a piece of bread in the container with them", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drghnbz", "drgifj8"], "text": ["The cookies absorb the moisture from the bread, so you couldn\u2019t use stale or naturally hard bread to get the same results as you would from a nice fresh slice of soft wheat or white bread. If its an enclosed space its normal for moisture to transfer to dryer substances in this space.", "Cookies are crunchy because they have little water. Bread is soft because it has a lot of water. If you put the two together, water will evaporate from the bread making it tough and chewy, and will be absorbed into the cookies making them soft."], "text_urls": [[], []], "score": [6, 3]}}, {"q_id": "7ks2lx", "category": "Repost", "title": "what is blue tooth?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drgqm6b", "drgqym8"], "text": ["Bluetooth is a high frequency radiowave communication system. It is not proven to be harmful.", "A radio signal is sent from one device to the other. Not that different from ones your FM radio uses. This type of electromagnetic radiation has been extensively studied for any negative health effects, and no link between it and negative health effects has been found. There also isn't any known way it could effect our health. Bluetooth uses similar waves as cell phone uses, but the transmitters are operating at significantly lower power than cell phone transmitters are, so even if you'd be convinced cell phones cause health problems(a proposition which has been studied and found false), using bluetooth devices would reduce the amount of radiation you receive by factor of 1000. So the gist of it is, there aren't many things in this world that have been scientifically proven to be as safe as bluetooth devices radiation. Eating bananas is demonstrably more dangerous for example."], "text_urls": [[], []], "score": [3, 3]}}, {"q_id": "7ks8vw", "category": "Repost", "title": "The theory of time travel via High Speeds", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drgroki"], "text": ["Basically, by travelling really fast, time slows down for the traveller. The formula for it is [here]( URL_0 ). As you get closer and closer to the speed of light, time for you slows down faster and faster. Note that it is not a linear relationship, so travelling at 10% of the speed of light does not slow your time down by 10%. Now, for example, if you travel at 80% of the speed of the light, following the formula you see that your time slows down by 40% relative to a stationary person. In other times, the other people are going through time 60% faster than you are. So if you traveled for 1 year at the speed of the light and arrived at another planet, the people on the planet would actually have aged 1.6 years, and you had *traveled* into the future by 0.6 years."], "text_urls": [["http://www.walter-fendt.de/ph14e/timedilation.htm"]], "score": [3]}}, {"q_id": "7kvjll", "category": "Repost", "title": "how can the universe be finite? If it has a putter boundary, doesn\u2019t there have to be something (even empty space) beyond it?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drhixbi", "drhi8w6", "drhifne", "drhhro4"], "text": ["The universe is not finite. The *observable universe* is finite. Light has a fixed speed. We can only see as far as (light speed) divided by (the amount of time passed). The universe itself is infinite. What does that mean? Imagine traveling in one direction until you get to the edge of what you can see currently. What would you see as you look out in the direction you were traveling? *More universe*. This will happen no matter how many times you travel to the edge of that observable universe, and no matter the direction. (This happens in a flat, open, or closed curvature universe). An analogy would be sitting on a ship in the sea. What you can see from that ship is the *observable universe*. But if you sail to the farthest point that you can see, you'd still just see more sea. You can keep sailing in that direction, and you'll never get to the end. *You might even end up exactly where you started*, but you'd still never reach the \"end\". The sea you are traveling in is infinite, in the mathematical/physical sense. While the area of sailable locations might be finite, the topology of sailable locations is infinite. This is an example of closed topological curvature. Flat or open curvature are similar, except you'll never end up back where you started. You'll just keep getting further and further away from your origin if you continue on one direction (think the difference between an infinite 2d plane [flat] vs a 2d sheet of paper wrapped around a sphere [closed]). Edit: the Universe's expansion is somewhat answered by the infinite nature of it. The Universe is all inclusive. So it is \"expanding\" into *itself*. There's really not an excellent way to describe it, Just a lot of thinking. The Universe's expansion isn't like an explosion, or blowing up a balloon, or a loaf of rising bread. **If** the things that make up the explosion, or the balloon plus things inside, or the bread dough, where a representation of everything that is, was, and ever could be, then using them as an example for the Universe's expansion would be somewhat accurate. The point is - you can never be \"outside\" the universe. It is *everything*, so it's expansion is into *something*, and *something* is apart of *everything*, so it's expansion is into itself.", "It's not clear what the volume of the universe is, or even if a three-dimensional volume is the correct description. A sphere has a finite area, but no edge. The universe may be similarly bounded and unbounded. It does appear to have finite *matter* though, infinite mass (even at great distances) would cause problems in our current understanding of gravity and universal expansion.", "Ah the old what's beyond our observable universe question. Simple answer is no one knows if it's finite or infinite or whatever. It's pure speculation.", "I think when people say finite they mean that if you go a googol light years away, you'll actually be in 'empty space', but there will be a discrete 'finite' universe that may still be expanding into that empty space. An interesting thing to think about though is that the electromagnetic field permeates all of space, and so long as there is a field you'll always have the spontaneous generation of particles and antiparticles. So even if you leave the universe you'll still have stuff popping in and out of existence around you."], "text_urls": [[], [], [], []], "score": [18, 17, 4, 4]}}, {"q_id": "7kx88x", "category": "Repost", "title": "If air particles are moving around randomly at very high speeds, how does wind occur and what happens to the air particles?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drhv54c"], "text": ["They blow my mind! Just kidding. Mostly particles are more vibrating rather than running around crazy. When you get wind it's because of high pressure and low pressure zones in the atmosphere and the wind 'flows' like water 'downhill', or to the area of low pressure. Then the air particles are actually moving."], "text_urls": [[]], "score": [3]}}, {"q_id": "7l6szc", "category": "Repost", "title": "What Mastering is, when music gets Remastered.", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drjztzb", "drk0pyj"], "text": ["So let's say we have an old recording of something. Like The Beatles (Sgt. Peppers was just remastered for example). In older music the recording methods were not near the levels of perfection that we currently have. Audio samples might have some interference that was undesirable and couldn't be entirely removed. This is easier with digitization. We can also take old samples and boost different frequencies, change the volume, change the dynamic range. You can pretty much change any property of the sound you want. Another example is mono and stereo. Old records (The White Album for example) was mixed for mono, all the audio plays out on channel. This conformed to older system standards. Eventually people bought stereos that were able to have multiple channels so now you can play the guitars out one and the singers out the other so it sounds clearer. Changing from mono to stereo is another form of remastering. TLDR: You scrub undesired noise from the recording and add effects to create the \"perfect\" sound.", "A *master* is the original finished copy of a piece of audio or video. Before the 1980s, all masters were analog. Copying it meant playing it, and each time you played, it would wear out a little. Masters were used a little as possible, you'd make 10 copies, then 10 copies of each of those copies, etc., until you had all that you needed. Between occasional copies and just the physical breakdown over time, the quality of the master would degrade. Remaster means two things. First, you convert the master to digital, which does not wear out. Then you carefully process the digital copy to remove and repair an imperfection, resulting in a better version that will never break down."], "text_urls": [[], []], "score": [5, 4]}}, {"q_id": "7l6zz2", "category": "Repost", "title": "Why do our eyes get heavy and blurry when we are sleepy?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drk5ndp"], "text": ["Quite simply, you eye muscles are tired. You might have been staring at something for a long time (such as a screen or road) or just might have had a long day. Keeping your eyes open and blinking takes energy, and using a muscle too much can make it sore."], "text_urls": [[]], "score": [5]}}, {"q_id": "7l8oi7", "category": "Repost", "title": "How does binary code operate computers with a series of 1s and 0s?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drkcmj6", "drkdmli", "drkcq7o"], "text": ["Your computer CPU has lots of transistors and those 1's and 0's tell those transistors to turn on or off. Like a bunch of light switches basically.", "The best answer I got for this is by u/r00nk which I have saved. Here it is: > Lets dive right into the magical land of data. > Whats the symbol for five? 5. Whats the symbol for ten? 10. But wait, isn't that the symbol for one and zero? Right, so in our numbering system, when we get to the number ten, we write the symbol for one and zero. > There is no symbol for ten, we simply recycle the ones we already have. Because of this, we call our numbering system \"base-ten\", or \"decimal\". > \"Ones and zeros\",\"true and false\", and \"on or off\" are all terms you have probably heard before. What these all are referring to is a different kind of numbering system. For our decimal system, we write a '10' when we get > to ten, but for binary, we write a '10' when we get to two. There is no symbol for two in binary, exactly how there is no symbol for ten in decimal. \"On\" or \"off\" simply refers to '1' or '0' in binary. > Just to make sure that makes sense (as its super important): > 01 = one; > 10 = two; > 11 = three; > Make sense? Cool (if not google \"binary\"). > Ok, now for something completely different, but related. > Theres something in computer theory called a \"logic gate\". It's a device. It has two inputs, and one output. The only input it accepts is \"on\" or \"off\", and the output is the same, \"on\" or \"off\". You might see the relation to > binary. > A logic gates output is based on its input. An example of a logic gate is a \"AND\" gate. When both of the inputs are on, the output is on. Otherwise, the output is off. > You still with me? Don't worry, the cool stuff is coming soon. > Another logic gate is the \"NOT\" gate. The NOT gate has one input. If the input is off, the output is on, and vice versa. The output is not the input. Get it? > Now, if we put the input of a NOT gate on the output of an AND gate, we get a NAND gate. Creative, I know. We nerds don't get out much. Anyways, try to figure out what the output would be for all the four different possible combinations of the two inputs for the NAND gate. > [Anyways, heres what a NAND gate looks like drawn.]( URL_2 ) > Now, you have probably heard of computer memory right? [**ta da!**]( URL_0 ) > It's not going to make total sense at first, but that diagram shows a memory-holder-thingamajig. Look at it for a while and try to figure out what it does. Basically it holds a \"bit\" of memory. You could say that a bit is like > one digit of a binary number. You line a bunch of these in a row, and you can start holding numbers. > But what do you do with those numbers? > This is where it gets cool. You do math with those numbers. This next device is called an \"adder\". > The gate on top is called an XOR gate, its output is on if only one of its inputs is on. If there both on or off, then the output is off. > Now, make it [a little more complex]( URL_1 ) and you can add multiple bits at the same time, by linking the last ones \"Cout\" to the next ones \"Cin\". > Cool, now we have a basic calculator. How can we turn this up to 11 and make a computer? > Code. > Now, you know what data is, and so code is easy to explain. Its just data. Thats all it is. Really. > The reason why its different then other data though, is because the CPU interprets it as instructions. > f we wanted to do math for example, and we got to decide the instruction definitions we could use a system like; > 00000001 = *add* a number to another number; > 00000010 = *subtract* a number from another number; > With this, we can set what logic gates are being used based on data. > Now, real quick, memory is organized on a computer by something called memory addresses, basically they just allow the CPU to ask for memory at a specific location. Generally speaking the addresses are sized by \"bytes\" which is just another word for \"eight bits\". So if we wanted to access memory location five or whatever we could store that as '00000101'. > Lets go back and add some more to our table; > 00000011 = move this data into some location; > Cool, now we can say something like: > \"add the number at location #5 in memory to the other number at location #7 in memory.\" > By breaking it down into: > (add) (memory address #5) (memory address #7) > Which is really just > 00000001 00000101 00000111 > Pretty sweet right? > But hold on, how does the CPU know where to get its instructions? > On the cpu, Theres a tiny amount of memory, it does various things, such as hold something called the \"instruction pointer\". The instruction pointer holds the address of the next instruction, and increments itself after every instruction. So basically, the cpu reads the instruction pointer, fetches the next instruction, does it, adds one to the instruction pointer, and then goes back to step one. > But what happens when it runs out of instructions? > Lets go back to our table. Last time, I promise: > 00000100 = set instruction pointer to address > Basically, all this instruction does is set the instruction pointer to a number. You ever wonder what an infinite loop is on a computer? Thats what happens when an instruction pointer is set to instructions that keep telling the instruction pointer to set itself to that same set of instructions. > Thats computers in a nutshell.", "I guess I'll tackle this. When dealing with electricity, the easiest way to send a signal is having it on (flowing, or in binary, 1) or off (not flowing, 0). Within a CPU, you will have tons of logic gates. These logic gates have what are called transistors, which are very small switches of sorts. Logic gates take inputs and give an output. There's a ton of them, and you need a lot to get a functioning computer. Having a lot of logic gates working together will let you process all sorts of things. But if you Google logic.gates, the Wikipedia has a TON of useful pictures and stuff to better visualize logic gates as well as all of their functions."], "text_urls": [[], ["https://en.wikipedia.org/wiki/Flip-flop_(electronics)#mediaviewer/File:SR_Flip-flop_Diagram.svg", "http://i.stack.imgur.com/0rqZz.png", "https://en.wikipedia.org/wiki/NAND_gate#mediaviewer/File:NAND_ANSI_Labelled.svg"], []], "score": [6, 5, 4]}}, {"q_id": "7lck80", "category": "Repost", "title": "how do people mature things like steaks without them rotting?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drl7lcr"], "text": ["Yer not alone in askin', and kind strangers have explained: 1. [ELI5: How dry aging meat doesn't make it dangerous. ]( URL_1 ) ^(_ > 100 comments_) 1. [ELI5: How dry-aging meat does not spoil even after 200 days? ]( URL_2 ) ^(_24 comments_) 1. [ELI5: Why does aging steak not cause it to go bad? ]( URL_11 ) ^(_2 comments_) 1. [ELI5: How are cuts of beef \"aged\"? ]( URL_8 ) ^(_1 comment_) 1. [ELI5:How does aging meats and things like cheese work and not just make them rot and gross? ]( URL_9 ) ^(_17 comments_) 1. [ELI5:When you dry age beef, why doesnt it just rot and spoil? What all is going on? ]( URL_10 ) ^(_3 comments_) 1. [ELI5: How can a butcher \"age\" beef for a large period of time (21 days etc.) yet if you were to take the same cut of meat not aged and leave it in the fridge for a time after its expiry it would turn rancid and have to be thrown out? ]( URL_5 ) ^(_7 comments_) 1. [ELI5: why is it safe to dry age beef, but unsafe to keep supermarket beef in the fridge for more than a few days? ]( URL_4 ) ^(_7 comments_) 1. [How is beef dry aged? ]( URL_6 ) ^(_2 comments_) 1. [ELI5:How do you \"dry age\" beef? Is it safe to eat this dry age, or does it pose serious risks like tar tar? ]( URL_3 ) ^(_5 comments_) 1. [ELI5:Why is some food \"aged\" and still edible while others are rotten and tossed out? ]( URL_7 ) ^(_20 comments_) 1. [ELI5: how can a steak be matured for 28 days, but have an expiration date of 3 days when on the store shelf ]( URL_0 ) ^(_21 comments_)"], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/355m22/eli5_how_can_a_steak_be_matured_for_28_days_but/", "https://www.reddit.com/r/explainlikeimfive/comments/2fsz5c/eli5_how_dry_aging_meat_doesnt_make_it_dangerous/", "https://www.reddit.com/r/explainlikeimfive/comments/6ngkbx/eli5_how_dryaging_meat_does_not_spoil_even_after/", "https://www.reddit.com/r/explainlikeimfive/comments/2ob914/eli5how_do_you_dry_age_beef_is_it_safe_to_eat/", "https://www.reddit.com/r/explainlikeimfive/comments/6n5eh6/eli5_why_is_it_safe_to_dry_age_beef_but_unsafe_to/", "https://www.reddit.com/r/explainlikeimfive/comments/35r2s0/eli5_how_can_a_butcher_age_beef_for_a_large/", "https://www.reddit.com/r/NoStupidQuestions/comments/42mxj0/how_is_beef_dry_aged/", "https://www.reddit.com/r/explainlikeimfive/comments/7gamwl/eli5why_is_some_food_aged_and_still_edible_while/", "https://www.reddit.com/r/explainlikeimfive/comments/2jnft1/eli5_how_are_cuts_of_beef_aged/", "https://www.reddit.com/r/explainlikeimfive/comments/6992vi/eli5how_does_aging_meats_and_things_like_cheese/", "https://www.reddit.com/r/explainlikeimfive/comments/38kvl9/eli5when_you_dry_age_beef_why_doesnt_it_just_rot/", "https://www.reddit.com/r/explainlikeimfive/comments/1si9xe/eli5_why_does_aging_steak_not_cause_it_to_go_bad/"]], "score": [5]}}, {"q_id": "7lcvzo", "category": "Repost", "title": "When breathing humid air, what prevents our lungs from filling with water (like a dehumidifier)?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drla9z1"], "text": ["Because you breathe *out* humid air as well. A dehumidifier requires special equipment to extract the water from the air."], "text_urls": [[]], "score": [6]}}, {"q_id": "7leszf", "category": "Repost", "title": "why do fans collect so much dust", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drlq2cw"], "text": ["There is a certain amount of dust in the air in a room, and as the fan is circulating the air, it has the chance to collect more of it as compared to something passive like a table top. For the table top - only the dust that happens to float by might have a chance to land. The other thing is the friction of blades churning through air creates static charges which then draw dust particles out of the air and they cling to the charged surface. There are actually air filtration systems that use this idea to pull particles out of the air - by forcing it through an intentionally charged up grid."], "text_urls": [[]], "score": [3]}}, {"q_id": "7lgc6i", "category": "Repost", "title": "Why do pilots sometimes ask you to turn off all electronic devices when there is poor ground visibility?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drm13pv"], "text": ["The instruments that the pilots use, called the *Instrument Landing System*, is a sensitive device. The small interference from cell phones or other radio devices can disrupt the radio signals from the ground to the plane and vice versa. In conditions where there is low ground visibility, pilots go for the safe route and ask that you turn the devices off to be sure that they receive accurate information that is crucial for landing and these devices can interfere with the readings given. In such poor conditions, there are a lot of things that can do wrong, so to be safe they ask you to turn them off."], "text_urls": [[]], "score": [9]}}, {"q_id": "7ljk82", "category": "Repost", "title": "Why do some smells like gas smell so strong and the smells stays for so long but for something like a cup of tea you need to come close to smell it", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drmpkil", "drmp4wo", "drmpgdk"], "text": ["The stuff that makes gas smell \"like gas\" is actually tert-Butylthiol (t-butyl mercaptan). This is a chemical that humans can detect in very small amounts. Ordinary methane is odorless, which is a safety problem when leaks are possible.", "Part of the answer is \"volatility\" or how easily a substance evaporates and then disperses through the air. This might be what you're looking for. There's also a question of concentration-- gasoline is mostly \"smelly stuff\", while tea is mostly water, with some of that stuff added. And we're more sensitive to some smells than others, for reasons which are insanely complicated (some of it is what you'd expect, though-- smells that are dangerous to us or unusual get our attention because it's useful for us to be aware and cautious around them).", "The type of gas that runs through your house that you heat and cook with is given a strong smell so it\u2019s easily detectable. Tea is just water with leaves, very neutral."], "text_urls": [[], [], []], "score": [8, 6, 4]}}, {"q_id": "7ll2to", "category": "Repost", "title": "How do modern smartphones and devices know what battery percent they\u2019re on?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drn1hge"], "text": ["Batteries lose voltage as they drain. So a computer that can read its own battery's voltage and has seen how high/low it goes in a charge cycle can guess how much charge is left, and guess (with less accuracy) how long it'll take to drain."], "text_urls": [[]], "score": [3]}}, {"q_id": "7lncrp", "category": "Repost", "title": "What is asbestos and why is it dangerous/lethal?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drnj1uc", "drnjyix"], "text": ["It is a fibrous material (like the hair on a coconut) that can create little bits of dust that are easy to breathe in. These little fibers hang out in your lungs, and if there are too many of them, it gets really hard to breathe.", "[It's a mineral that has a microscopic structure like fibers.]( URL_2 ) [It makes for a great insulator, and does not burn, so it was made into cloth and wrapped or stuffed into just about everything.]( URL_3 ) [It was so fluffy, it was even used as fake snow on movie sets.]( URL_4 ) [Turns out that the dust can get into your lungs and poke your cells so bad that you get lung cancer.]( URL_1 ) So it was (eventually) banned from being used, but not before it was used in just about everything. [So now, when people want to remove it from an old building or something, they have to jump through all kinds of hoops and wear hazmat suits.]( URL_0 )"], "text_urls": [[], ["https://cdn.fixr.com/media/images/cost-guides/asbestos-removal.jpg", "https://i.imgur.com/waiKMLA.png", "https://4.bp.blogspot.com/-Z1AagMk5r74/WRg2t16OZ5I/AAAAAAAAGN4/Hr4nP4yMegQgY0K7nDWvuYe7JNClXoxDwCLcB/s1600/16.jpg", "https://www.asbestos.com/wp-content/uploads/asbestos_house_diagram.png", "https://i.imgur.com/MxUvejl.jpg"]], "score": [18, 6]}}, {"q_id": "7lnvv1", "category": "Repost", "title": "how did clocks stay in sync back in the 1800s?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drnmklt", "drnmtpg"], "text": ["you have one master clock in town, and everyone syncs their clock to that. hopefully you have a competent master clock caretaker. London's Big Ben is literally what that's for.", "The nearest train station was the best place to set your watch because there was a telegraph system that connected and synched clocks between stations. If I remember correctly they were accurate to within 2-3 minutes. How accurate a watch stayed is anyone's guess and dependent on the quality of the watch. Chances are good that the further someone lived from a train station, the less concerned they were with accurate time."], "text_urls": [[], []], "score": [7, 3]}}, {"q_id": "7lphla", "category": "Repost", "title": "Who was Henrietta Lacks and why are her HeLa cells so important?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drnzv9h", "drnye5i"], "text": ["The problem with cancer cells is that, among other things, they don't undergo programmed cell death. All of the cells in your body have genes in them coding for when they should die, so they can make room for new cells. Cancerous cells have a mutation or damage to those genes, so they don't die when they're supposed to. Even so, cancer cells still eventually wear out and die. Henrietta Lacks' cancerous tissue didn't. The cells just kept dividing and growing when isolated in the lab. That tissue is, essentially, immortal. Samples from that original tissue are *still* alive and in use today. The immortal tissues allow scientists to study all kinds of things that normally require a human patient (or close enough animal substitute) because they need to study the long-term effects of something on cell growth - something you can't do with a normal tissue sample because the cells will most likely die after dividing around 40 times regardless. It also gives you a perfect control sample, since you know your control will be genetically identical to the sample being tested. The tissue was taken without Henrietta Lacks' consent, which at the time was not unusual. And not only because she was a black woman, but because informed consent wasn't really a concept anyone used then. [Relevant SciShow]( URL_0 )", "She was a Black woman who got cancer and had a tumor biopsied in the 1950s. Her doctor decided to use the biopsied cells for research without her consent. This is, of course, fucking terrible, but it was normal at the time. I'd like to imagine that we've all grown a lot since then. Anyway, it's easier to order an existing cell culture than to find someone with a tumor that's being biopsied around the time you need to do your research. It also makes results more reproducible: you can tell someone else that this treatment kills HeLa cancer cells but has no effect on some other, non-cancerous cell culture, for instance. They're also used when you just need human cells rather than cancer cells in particular. They're cancerous, which means their behavior doesn't precisely match healthy human cells, but on the plus side, they don't stop reproducing. That means the same line of cells can be used for centuries."], "text_urls": [["https://www.youtube.com/watch?v=sXY6-wLesYY"], []], "score": [5, 3]}}, {"q_id": "7lqoo0", "category": "Repost", "title": "irrational coefficients Pi and e", "title_urls": {"url": []}, "selftext": "Im an engineering student, and at times when Pi or e appear in formulas it makes no sense why is it there for first, and then how did it even originate. Okay, I know how the Pi was created. But sometimes I dont understand when in formulas it appears, when there is no apparent connection to circles. ( Could be underlying physics rules though) And the second one is natural number e 2.7.. how in the world was it created and how did someone think its going to be important for.. again.. so many formulas and equations. I use it all the time, but when I think about it. It hardly makes sense", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dro7nty", "drowxvj", "dro7k47", "drooe6k", "drocbnn"], "text": ["Without knowing the specific formulas, it would be impossible to answer why they involve pi or e. Sometimes it even baffles scientists and mathematicians. But, e, that's easy to answer. Imagine a bank that returns 100% of your investment at the end of the year. You put in $1 in at the beginning you get $2 out. Let's take that same bank and compound the interest bi-annually. Instead of getting 100% at the end, you get 50% of your investment 6 months in, then 50% of *that* at the end. You put in $1 in the beginning and get $2.25 out (1 * 1.5 * 1.5) Three times a year you'd get $2.37. (1 * 4/3 * 4/3 * 4/3) n times a year can be calculated by the formula (1 + 1/n)^n As n approaches infinity, your return approaches an irrational number, approximately 2.7182... and given the label *e*. *e* is the amount of money you'd get back each year from a bank that nets 100% return and compounds your interest continually.", "Pi is related to circles but it's also part of the formula for sine and cosine, which are related to angles, waves, and periodic functions. So anything periodic or involving waves will probably involve pi somewhere.", "Yer not alone in askin', and kind strangers have explained: 1. [ELI5: What is Pi? Why does it exist? Why was it created? And why is it \"infinite\"? ]( URL_1 ) ^(_ > 100 comments_) 1. [ELI5: How does Pi work, how was it discovered, and why is it so critical in mathematics? ]( URL_0 ) ^(_ > 100 comments_) 1. [ELI5: The number 'e'. ]( URL_9 ) ^(_41 comments_) 1. [ELI5:How were the values of constants such as e and pi historically determined, and why do these constants find themselves in so many formulae? ]( URL_7 ) ^(_7 comments_) 1. [ELI5: What makes the number e so special and why is it used as the base of the natural logarithm? ]( URL_8 ) ^(_90 comments_) 1. [ELI5: The concept of e in mathematics. ]( URL_2 ) ^(_26 comments_) 1. [ELI5:How was Pi discovered? ]( URL_11 ) ^(_ > 100 comments_) 1. [ELI5: What is 'e' in math? ]( URL_3 ) ^(_16 comments_) 1. [ELI5: In simple terms, what does the mathematical constant \"e\" mean? ]( URL_4 ) ^(_21 comments_) 1. [ELI5: Why does e (the number) come up in so many seemingly random applications? ]( URL_6 ) ^(_ > 100 comments_) 1. [ELI5: Why is the number PI such a big deal? ]( URL_10 ) ^(_7 comments_) 1. [ELI5 why the value of pi is very important? ]( URL_5 ) ^(_18 comments_)", "e^(Pi*i)+1=0 There is a reason these (pi and e) occur so often (efficiency of geometry and the efficiency of compounded growth... respectively), but it is still quite amazing how much we misrepresent how powerful they are.", "Wherever there's a pi, there's a circle. Generally, it pops up in physics because stuff is radially symmetric, which means everything looks the same when you rotate. This simplifies things, and puts a pi out front because you're doing everything in circles. But pi pops up in statistics and factorials and many more things. All of these have some connection with planar or Euclidean geometry, where pi is sort of the number that describes how it works. For example, pi is in the formula for the Normal Distribution. But this is because you use properties of the circle to find the area under such a curve, and the functions involved turn out to work nicely with circles and planar geometry. So pi pops up."], "text_urls": [[], [], ["https://www.reddit.com/r/explainlikeimfive/comments/4a2etu/eli5_how_does_pi_work_how_was_it_discovered_and/", "https://www.reddit.com/r/explainlikeimfive/comments/2lr9hk/eli5_what_is_pi_why_does_it_exist_why_was_it/", "https://www.reddit.com/r/explainlikeimfive/comments/5a8xwn/eli5_the_concept_of_e_in_mathematics/", "https://www.reddit.com/r/explainlikeimfive/comments/2xv91z/eli5_what_is_e_in_math/", "https://www.reddit.com/r/explainlikeimfive/comments/2vduss/eli5_in_simple_terms_what_does_the_mathematical/", "https://www.reddit.com/r/explainlikeimfive/comments/k4vzr/eli5_why_the_value_of_pi_is_very_important/", "https://www.reddit.com/r/explainlikeimfive/comments/6f40be/eli5_why_does_e_the_number_come_up_in_so_many/", "https://www.reddit.com/r/explainlikeimfive/comments/5pu36m/eli5how_were_the_values_of_constants_such_as_e/", "https://www.reddit.com/r/explainlikeimfive/comments/1quw6t/eli5_what_makes_the_number_e_so_special_and_why/", "https://www.reddit.com/r/explainlikeimfive/comments/3c0rti/eli5_the_number_e/", "https://www.reddit.com/r/explainlikeimfive/comments/2mth8h/eli5_why_is_the_number_pi_such_a_big_deal/", "https://www.reddit.com/r/explainlikeimfive/comments/1w35tr/eli5how_was_pi_discovered/"], [], []], "score": [22, 8, 4, 3, 3]}}, {"q_id": "7lslav", "category": "Repost", "title": "Why do some materials become brittle when they get cold and others do not?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dropgav", "drp379v", "drozc37", "droojci", "drp6q5i", "drovdk2", "droq9ph"], "text": ["This is more ELI am a teenager. I'm sorry, but it's the best I can do. When a material fails, it can fail in two different ways. One way is for the material to deform which is caused by the atoms in that material moving past one another. This is called plastic flow. The other way, is for a crack in the material to propagate all the way through the material cleaving it into two different pieces. This is called crack propagation. In general, failure of a material is heavily dependent on its atomic structure. In some types of materials their susceptibility to fail from plastic flow is heavily temperature dependent, while its susceptibility to failure through crack propagation is not. When these types of materials get cold they lose their ability to fail due to plastic flow (which is synonymous with their ability to deform), and so crack propagation takes over. When a material fails through crack propagation instead of through plastic flow, we call this a brittle fracture. Materials that show this change in susceptibility to plastically flow are said to go through a [*\"ductile to brittle transition.\"*]( URL_0 ) What this means is that some materials when they are warm fail due to plastic flow but when they get cold they begin to fail in a brittle fashion. As a disclaimer, I will add that almost all materials become more brittle as they get colder, but some materials still stay what we would consider ductile as their temperature drops. This is due to the fact that plastic flow becomes easier when atoms are further apart which is the case when a material is warmer. Atoms are vibrating more quickly, and so on average they are farther apart from one another in a warmer material. Because of this they can slide past one another more easily, which is essential for a material to deform. Conversely, a material that is brittle will fail without deforming much at all... It will simply crack all the way through. Credentials: I am a PhD candidate in mechanical engineering, specializing in Mat. Sci. and I often guest lecture for the Mat. Sci. and Engineering course at my college.", "Like others have said, it\u2019s more of a question of *when* a material gets brittle, not if. That said, the reason the temperature varies is that the atoms can be arranged in different ways that can then move (dissipate energy) in different ways. The best example I can think of is casserole. Imagine a casserole made of small regularly shaped noodles like penne. Put it in the refrigerator. If you tried to break off a piece with your hands, it\u2019d be pretty easy (brittle). Now imagine making be same dish but using spaghetti...suddenly when you try to break off a piece, it is tangled with the rest of of the casserole and doesn\u2019t break off as easily or cleanly (ductile)! That said, if you put it in the freezer instead of just the fridge, it\u2019d probably break in either case.", "Y\u2019all need to chill about brittle transitions and glass transitions. You need to take it back to what\u2019s causing all of this in the first place. Energetics and kinetics. Yes bcc metals will often be more ductile than hcp bc of slip planes in the system. Yes metals are more ductile bc of metallic bonding. Yes polymers experience a glass transition that allows for polymer flow to begin. Sure whatever fine. Elit: But the reason materials fail in a brittle fashion in colder temperatures is because it\u2019s more convenient to break bonds than it is to create more disorder in the system. go look at a stress strain curve and take the integral. The area under the curve is the toughness of the material, how much work it can take before failure. Work and heat are the similar, and heat capacity is dependent on temperature. Hotter the material, more work can be done. How much the heat capacity varies in temperature determines how much more brittle it will be as it gets colder. Then compare to what is favorable, adding entropy in forms of dislocation, or break a bond.", "What doesn't get brittle when it gets cold? It is a matter of your \"cold\" scale. My memory is incomplete, but I believe only Helium won't \"freeze\" to a solid state (and it can under special conditions). I'm sure someone can fill in my gaps here. A common solid you may be thinking of would be a metal. Metals are malleable (depending on metal/alloy) due to metallic bonding. Metallic bonding is like an old school stereotype of a hippie commune. Electrons are shared pretty easily, and the atoms slide between partners easily. When cooled further the atoms tend to form lattice structures, like crystals. For the analogy, the atoms are forming long term partnerships like marriage, children, and perhaps get a little selfish with their atoms (though some brittle materials like superconductors share electrons like madmen). These structure cannot slide or move (much). The colder a material gets, the more lattice forms until CRACK! An analogy marriage ends with a full divorce and they are arguing over who gets to keep the box set of Friends.", "Just like how some materials boil faster than others some materials freeze faster than others. All materials will become brittle at a certain freezing temperature. This has a lot to do with water content. For those things with little to no water content you will have to go to an extremely low temperature to make them freeZe enough to become sufficiently brittle that you can break them easily. Why do objects become brittle ? Because the bonds between molecules weaker as there is no room for movement.", "Ok, so everything will break if the rate at which you deform it is high enough. Think about silly puddy, if you pull it really quick it will snap. Let's call this 'brittle yield strength' - how high of a strain rate something can have applied to it before it breaks. It just so happens that some materials have interesting atomic and molecular properties which make then have lower brittle strain rates as they get cold, and others are not as sensitive. A true ELI5 is difficult without a few basic chemical principles.", "In material science, this phenomenon is known as the ductile to brittle transition temperature (DBTT). Once a material is cooled below a certain temperature, it will exhibit brittle fracture characterized by a lack of plastic deformation before failure (no yield). There are several different mechanisms responsible for this behaviour depending on the material. The best understood mechanisms is in body-centered cubic (BCC) metals. BCC refers to the crystallographic alignment of the atoms (crystal structure), which varies from metal to metal. So to answer your question, the mechanisms responsible for a material's DBTT are not always well understood but in the case of metals it is strongly influenced by the material's crystal structure."], "text_urls": [["https://www.intechopen.com/source/html/50809/media/fig1.png"], [], [], [], [], [], []], "score": [1689, 42, 30, 10, 5, 3, 3]}}, {"q_id": "7luceo", "category": "Repost", "title": "Can someone explain SpaceX contrail pattern to me?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drp2e6z"], "text": ["Right, I'm an expert because I saw an image explaining it an hour ago and I've read some hard sci-fi. First, It was bright because it was high enough to catch sunlight after the sun had set on ground level. As it climbed it stayed thin, then it stopped. It stopped and started again because this is the first stage stopping and separating and the second stage starting. Then the plume started to expand. This happened for two reasons. First, at higher altitudes the air is thinner and the exhaust gas expands more than it does lower down. This is usually not observed because it would be difficult to see against a daylight backdrop. Secondly, the first stage, still traveling at high speed just behind the now separated and firing second stage, had turned around and fired its main engine to slow down. SpaceX has this nifty trick of bringing the first stage back and using it again. The exhaust from the first stage and second stage were blasting into each other like the wands of harry potter and ol' no-nose. They decided not to land this one to reuse, but wanted to pilot it to a safe place anyway. Good guy SpaceX. Lastly the fairings (thin aerodynamic covers) had poped off (intentionally) and were flipping over in the wake, creating some pulsing dots in the fat exhaust stream. I think I covered it all, make sense?"], "text_urls": [[]], "score": [5]}}, {"q_id": "7lux0x", "category": "Repost", "title": "In cartoons, why are objects that are interacted with a different color than static objects?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drp5b7w"], "text": ["It has to do with saving effort where you can, plus the timing associated with producing cartoons. In the clip you show, Spongebob is interacting with only a couple objects including the board in question, but the rest are entirely still. For everything else, a \"background artist\" has to paint it only once for the entire sequence in the cartoon because it's still and not moving. (That background stays in every shot, and the moving parts are on transparent plastic or digital images placed on top of it, depending on how the cartoon is produced.) Because it will move, that board is actually drawn *on top of* the background part of the image - the hole it sits in - as a different layer, so when it's ripped up (removed), you can see the hole. And because it moves, every frame in the image must deal with that board separately. So not only is it drawn later on top of the background image, there are about 10 frames or so where Spongebob was tugging at it and it was changing in appearance. So that's 1 copied-many-times original board, 10-or-so changing frames of bent board, and 1 copied-many-times image of the half-board left after it snaps. And all drawn later than the original background pic so you know precisely where to put that board. The combination of keeping things simple without perfect shading so it's much faster to produce that sequence in the cartoon, and drawing it later, adds up to the colour difference. P.S. You could often REALLY see this in older cartoons with lots of background interaction. Lots of cases in Scooby Doo and Looney Tunes where you knew some part of the background was going to get changed somehow."], "text_urls": [[]], "score": [12]}}, {"q_id": "7m1071", "category": "Repost", "title": "Calculus and why it\u2019s important to our day to day lives", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drqjwhs", "drrj8z0", "drqm317"], "text": ["Calculus measures the rate of change of things. So anytime you do the stuff equation: Change in stuff over time = (stuff in) minus (stuff out) plus (stuff generated) minus (stuff consumed) Thats calculus. And thats fundamental to any sort of process design ever. If it changes then you are using calculus. EDIT: time not tome", "The computer you're using was designed by people for whom calculus was indispensable in developing computer technology. So calculus might not be directly relevant to your life-you may not actually use it every day-it nevertheless is fundamental to modern society if we want to have all the technological innovations that need calculus to come into existence. I personally know nothing about plumbing. But without abundant, clean running water, and without modern sewage disposal systems, and without gas lines that heat my house, my life would not be very comfortable. In fact, without plumbing and people specialized in it, modern civilization is not possible. The same is true with calculus.", "First off if you want to actually learn calculus, I recommend Khan Academy's video series. I won't go into much mathematical details here. Calculus is the mathematics of change, it is useful because our world is constantly changing. I am not just talking about changes in time, I am also talking about changes of many things with respect to many other things. Here is a very simple example: You hang an object down from the ceiling with a spring. When you stretch the spring, you feel a force trying to restore balance. The more you stretch the spring, the stronger that force becomes. Here we have our first change: The restoring force increases with the stretch. Suppose we want to find out how exactly the end of the spring bobs up and down when it is released, ie we want to find a mathematical function of time, h(t), that predicts the height of the object at any time. Our relation for the first change can be summed up into a nice equation: F=-k*h(t) Where F is the restoring force. The minus sign indicates that the force always opposes the stretch. k is a number that tells you how strong the force is, and h(t) is the UNKNOWN mathematical function of time that we are trying to find. We then apply Newton's Second Law, which states that the force applied on an object causes it to accelerate. ie, the force causes the acceleration, aka the rate of change of velocity, aka the rate of change of the rate of change of height of the object. In mathematical language, it says: F = m*a = m*d^2 /dt^2 h(t) Where F is again the force, m is the mass/inertia of the object, and h(t) is the position of the object(again an unknown function in time). The notation d^2/dt^2 (A THING) means \"rate of change of rate of change of A THING\", in this case the object's height. If we combine the two equations together, we get m*d^2 /dt^2 h(t)=-k*h(t) And if we have the mathematical tools to solve the unknown function h(t), then we can predict exactly how the bob goes up or down. If you know calculus, you can work out that h(t)=A sin(sqrt(k/m)t) + B cos(sqrt(k/m)t). The height of the bob oscillates up and down, just as one expects. That is one of the almost infinite amount of applications of calculus to the real world."], "text_urls": [[], [], []], "score": [11, 3, 3]}}, {"q_id": "7m11cl", "category": "Repost", "title": "Why is water odourless?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drqjr0i"], "text": ["Because it's incredibly pervasive. Water is contained in tremendous amounts in the air already, in the form of water vapour, and with its amount measured as \"humidity\". If our nose had adapted during our evolution to smell it, it'd be smelling it ALL THE TIME. That would be entirely useless information so we didn't adapt to sense it. What we can smell, though is 'rain coming' or 'the salt seashore' or other smells associated with water. This is more because damp moist air carries smell to our scent receptors better than dry air, so other smells that we don't normally detect as easily come across as more intense. Water also causes some additional smells to come out of the environment, like that incredibly fresh smell you sometimes get from the woods after a summer rain. And it can affect temperature too, which is why woodland waterfalls often smell deeper and richer."], "text_urls": [[]], "score": [3]}}, {"q_id": "7m4isg", "category": "Repost", "title": "How do artificial neural networks work and how do machines learn?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drrat6r"], "text": ["A single neuron in an artificial neural network is just a thing that has some number of inputs and outputs that are either \"on\" or \"off\". The \"weight\" of each input is some number. If the sum of the weights of the inputs exceeds some value, you trigger the outputs. Those outputs can be the inputs to other layers of neurons. Exactly what an input is is entirely up to the person designing the system. They \"learn\" by adjusting all weights and arrangements of those neurons. This is not something the NN knows how to do on its own, it's something done externally. The NN is generally static once you've developed it and put it into work. They're not really all that complex, at least at the local level. Complexity comes in when you start stacking up thousands of nodes together and using complex methods to test & reprogram the weights of all those inputs."], "text_urls": [[]], "score": [5]}}, {"q_id": "7m549a", "category": "Repost", "title": "How do documentaries get to film organised crime from within like drug dealing, interviewing kingpins...etc?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drrgo17", "drrh2d6"], "text": ["Police can rarely compel reporters to give up their sources. It's protected. And it's not useful anyway. Who cares where some gang members did an interview months ago. There's no physical evidence of the crime that goes with the story. It's just that, a story, otherwise known as hearsay. It's not admissible in court.", "I\u2019m a documentarian, though never with that type of crime doc. But I\u2019ve read about and talked with others and am familiar with consenting process. I don\u2019t think there is one specific way, but I think often having one solid person who trusts you enough and you convince you\u2019re doing it from a journalistic standpoint and, probably more than anything else, you say you are putting a human face to crime, getting their point of view. You\u2019re probably not going to get the most badass and worst of the worst criminals, you\u2019re going to get the criminals that are open to a sympathetic filmmaker who is trying to get \u201cthe other side\u201d or their side of \u201cthe streets\u201d. As for legal, yeah, contracts can spell out how the film is for journalistic purposes... I\u2019m not sure how often courts don\u2019t try to challenge that, but a journalist (and a documentarian) can defend their ability to get a story and not have it be used in court."], "text_urls": [[], []], "score": [11, 3]}}, {"q_id": "7m5dpp", "category": "Repost", "title": "what makes fire invisible? And why are most fires orange/yellow?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drri7fz", "drril2k"], "text": ["The color is based on the energy level. Think of it like a rainbow. The lower energy, you have at the start of the rainbow. Red, orange, yellow. If it gets even higher, you can get green and even blue flames! Now if it gets so high, it can go beyond the visible spectrum. Still emitting light, of course, but you can\u2019t see it. So it\u2019s invisible. Or vice versa, below the visible spectrum. But usually that\u2019s too low energy to burn so it\u2019s rare. This is why you hear \u201cinfrared\u201d and \u201cultraviolet\u201d light. Infrared is below red on the visible spectrum, so you can\u2019t see it, but it\u2019s still light. Ultraviolet is above violet. Also can\u2019t see it. Edit: typo", "As a general rule, there's a relationship between the total heat of an object and the wavelengths of light it gives off. ([Blackbody radiation.]( URL_0 ) Most of the things which fall into the range of \"much more heat than we'd like in our watery blob bodies but still something we might live to see\" correspond to us as red, orange, yellow and eventually a whitish mix as some blues get added. In the fire, you're seeing high-heat atoms in the wood and some floating upwards. If it were a stronger fire (giving off atoms that have more heat) the color would be different. \"Invisible\" fires are often because it's pure gas combusting without any hot solid flecks which would be brighter and easier to see."], "text_urls": [[], ["https://en.wikipedia.org/wiki/Black-body_radiation"]], "score": [23, 3]}}, {"q_id": "7m5swl", "category": "Repost", "title": "Why does metal spark in the microwave?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drrlra3"], "text": ["Metal objects spark in microwave ovens because those objects have peaks and points where static charge can accumulate and spark out. If you could somehow get something metal in a microwave where the metal thing was both perfectly round and perfectly smooth, there would then be (presumably) nowhere on the outside of the metal thing for charge to accumulate. However, this doesn't mean there would be no accumulation at all. It would simply not be on the surface. (Physics Reddit, please correct me if I'm wrong.)"], "text_urls": [[]], "score": [3]}}, {"q_id": "7m630p", "category": "Repost", "title": "Why do plastic water bottles start to smell bad when left for a prolonged period after being opened?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drrnopy", "drrot22"], "text": ["2 Main things: 1 standing water breeds bacteria, so water left to sit will get nasty no matter what it is in. 2. cheap plastic bottles will leach plastic into them over time (and quicker if its warm). This is why all those bottles have small print saying not to reuse them. Its not too bad if its a day or 2, but you probably shouldn't reuse a bottle for more than a week (if that).", "Ahoy, matey! Yer not alone in askin', and kind strangers have explained: 1. [ELI5:Why does water left in bottles start to smell bad after a few days? ]( URL_0 ) ^(_19 comments_) 1. [Why does a plastic bottle start to stink after a while? ]( URL_3 ) ^(_5 comments_) 1. [ELI5: Why do many plastic water bottles cause the water to smell/taste bad after being opened and allowed to sit for a while? ]( URL_1 ) ^(_2 comments_) 1. [ELI5: Why do plastic bottles stink after a couple of days with the same water? ]( URL_2 ) ^(_3 comments_) 1. [Why does my water bottle keep smelling bad? ]( URL_4 ) ^(_9 comments_)"], "text_urls": [[], ["https://www.reddit.com/r/explainlikeimfive/comments/51kn0d/eli5why_does_water_left_in_bottles_start_to_smell/", "https://www.reddit.com/r/explainlikeimfive/comments/5ipyir/eli5_why_do_many_plastic_water_bottles_cause_the/", "https://www.reddit.com/r/explainlikeimfive/comments/56gkex/eli5_why_do_plastic_bottles_stink_after_a_couple/", "https://www.reddit.com/r/NoStupidQuestions/comments/79nd8r/why_does_a_plastic_bottle_start_to_stink_after_a/", "https://www.reddit.com/r/NoStupidQuestions/comments/5borqf/why_does_my_water_bottle_keep_smelling_bad/"]], "score": [7, 3]}}, {"q_id": "7m6wpo", "category": "Repost", "title": "Why does meat get tougher when you cook it through in the pan, yet when you slow cook it the meat is soft?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drrswvi"], "text": ["When you cook meat in a pan, all the moisture is removed. This makes the meat tough. When you cook meat in a slow cooker with liquids, it is absorbed into the meat which either breaks down the meat or makes it tender."], "text_urls": [[]], "score": [5]}}, {"q_id": "7mb35n", "category": "Repost", "title": "If there is no cellphone signal, how does the \"emergency calls only\" mode works?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drsnag8", "drsxmdn", "drsvqk9", "drsn6xz", "drsugqy", "drstxfr", "drsv6yj", "drsvibi", "drssc1h", "drswbem", "drswsyg", "drsuz9y", "drsz15l", "drsy4ab", "drt1nrj", "drt17f7", "drt6ix8"], "text": ["Your phone is allowed to use any network its physically capable of using for emergency calls, whereas normally it can only use networks you've paid to use E.G. signals from a Verizon tower. EDIT: Looks like I was partially wrong. Quoting /u/psfilmsbob \"Every carrier has roaming deals with other carriers who use the same signal, meaning your AT+T phone will work on T-Mobile towers, vice-versa. Same with every major carrier.\"", "My time to shine. I've written software for this -- if I say anything more, I might be identified easily by the people who know this. Edit: Important and useful distinction: At least one carrier needs to have coverage in the location you are trying to make an emergency call from. If none of them do, your cellphone won't be able to connect an emergency call. It's not magic, just engineering :) Edit: Since this got upvoted like crazy, disclaimer time. Do not use anything I've said here to make decisions on how you want to act in an emergency. Assume anything I've said below can be completely wrong. Having said that, I've been as truthful as I can be and as my memory serves me. The physical components for connecting to cell phone towers of various carriers and various tech (2G, 3G, etc) are mostly the same. The difference comes in which cell towers you tune to. A cell phone connects to a tower by \"tuning\" into what are called bands or channels. For something simple as GSM, it is literally frequency bands. For newer tech like CDMA and LTE, it's a bit more complicated because the tower signal jumps frequency bands and is mathematically encoded (stuff that even I don't understand well). When you buy phones from different carriers, they are set to ignore bands or channels that the carrier doesn't use. It serves several purposes - 1) to make sure you can't take to phone to another carrier 2) to make sure your phone doesn't waste time and battery tuning to cell towers that won't accept them (if you have an AT & T service, the T-Mobile tower will reject you even if you can talk to it) 3) Less testing of the phone necessary, etc. There's software that picks the best tower out of all the towers your phone can hear/talk to (you might be able hear/talk to multiple towers from your carrier, you want to pick the closest one or the one that supports the fastest data, etc). When you make an emergency call, the software that's responsible for picking to tower tells the tuning software \"THIS IS A FUCKIN EMERGENCY CALL. FULL SPEED AHEAD! CONNECT TO WHATEVER YOU CAN FIND\". The tuning software also keeps track of the last few bands/channels in which it saw any signal. It'll try them first so that you can connect the call quickly. If it can't find any, it'll do a full sweep of all the bands the physical hardware can possibly tune to. Once it finds a tower, the software for making calls says \"HEY MAN, I KNOW WE MIGHT NOT BE COOL WITH EACH OTHER, BUT THIS IS A FUCKIN EMERGENCY CALL MAN! CAN YOU PLEASE CONNECT THIS?\". The tower goes \"OH FUCK! SHIT! I'll connect you\". If the tower is at full capacity, it'll kick out someone who's not in an emergency call and then connect the incoming emergency call. In fact, you don't even need a SIM card (in some countries) or ever have had service in a cell phone to make an emergency call. That's why when there's no SIM card, the phone will still tune to a tower with good signal and show \"Emergency call mode\". This is to make sure we don't waste time when you actually need to make an emergency call. This is why if you are in an area with no cell service from any carrier, your phone drains the battery soon - because it keeps searching each band asking \"Can any tower hear me?\". So you should put it in airplane mode. And if you are in airplane mode and make an emergency call, it'll automatically get out of airplane mode. Again to save you time. In case your call disconnects, you phone will connect back to the same tower again. This is so that the carrier can try to locate you using the tower signals. If you had connected to another tower, the emergency people might have to connect to the different carrier and start locating you all over again. Disclaimer: don't try the next part in a real emergency unless you really don't have any other options. I'm not sure all phones do, but a significant portion of them will. Each country has a different emergency call number. It's 911 in the US, it's 112 (I think) in Europe, something else in Japan. What if someone goes to a different country and get into an emergency? They won't remember what that country's emergency number is -- so the software in your phone will see you are dialing 911 in Europe and go \"this person just wants to make an emergency call. I'll just connect to 112 instead\". There's a ton of cool stuff that goes on in your phone and the carrier to make sure we do absolutely anything possible to connect an emergency call. Hope this was an interesting read. **Edit:** Wow, this blew up way more than I expected. My most up voted comment by a wide margin. Really happy that so many of you enjoyed it as much as I did writing some of this software. It makes me emotional when I think about this work. And obligatory thanks for the Reddit gold. Edit: Also, so many people assuming that this means it's feasible to hack or asking if it's feasible to hack. No, it's super trivial to avoid hacking this to make free calls. The tower just needs to check the number you are calling is an actual emergency number. Also, I wouldn't be surprised if the emergency calls have special routing behavior to make sure it goes to your nearest call center. So it's even more easy to prevent free phone calls.", "After being stranded in the middle of the Big Bend backcountry, I can attest that calling 911, even on \u201cemergency calls only\u201d doesn\u2019t always work. Word to the wise, for any outdoorsy people on this thread: buy a satellite phone Edit: Story below in the comments but just thought I\u2019d put it here as well Its just good to have. We honestly couldn\u2019t\u2019ve prevented our situation. Friends foot was bleeding intensely and as a result we were not keeping pace with our water consumption. It was desert weather mid spring and no rivers, so we had to carry all our water the entire trip and it would\u2019ve taken days for my friend to get back, so we would\u2019ve run out. Ended up giving almost all our water to one guy so he can go all the way back himself to his car and go off-road to either come get us or get help. It was weird how valuable water sorta became, made me change my perspectives on life in a few ways. In a sense I knew that we could eat cactus to stay alive, and we knew the way back to the road, but just being put in that situation where things are kinda uncertain was strange. I remember giving that guy almost all our water and thinking that there was no way for me to know what is about to happen until it just sorta happened. Interesting experience 10/10 for life lessons 2/10 would do again The guy came back with his car, we got back within 20 ish hours", "There might be cellphone signal, it just might not be a signal from your phone carrier. Say you have a contract with company A, but all the cell towers around you can only connect you to company B. obviously you can't use that signal. However all cell phone networks, irregardless of what company they serve, must serve emergency calls by law. If your phone has any signal to any network around it it can make an emergency call, it just might not be able to make a normal call. EDIT: I will stand by my decision to use 'irregardless' despite the fact that it contains a double negative and is a nonstandard word. It is a true and tested word that has been[ causing fierce debates since the late 1800s]( URL_0 ), and I am proud to honor that tradition! ^^^sorry, ^^^won't ^^^do ^^^it ^^^again", "Emergency calls are attempted to be made no matter what, and on any network the phone can connect to. Normal calls, on the other hand, are not made this way.", "I had an emergency situation (car wreck in the middle of the night, 5m away from our tent) while backpacking in rural Chile, in the patagonia. The cell phone simply did not work.", "If I have an American cell phone and travel internationally will it work for local emergency number?", "Another thing that happens is that service may be limited in special circumstances. I'm not sure of all providers do this though. But in tje event of, say a natural disaster where people will be making a lot of calls they may limit service to only 911. My phone company also did this 2 occasions this summer, once when there was a major storm that cut power to the towers, so they're operating on emergency systems, and they prematurely did it when a wildfire threatened some towers.", "Let's you access any cell signal available no matter the carrier. Just as an emergency service. But if there is no signal from anyone I guess it would not work. Unless somehow it can connect to a satellite.", "The other answers about useing other companies towers are correct however most states have a department of natural resources, or US Forrest service, or Bureau of Land Management that maintains radio towers for short range radios. Lots of these have a CDMA and GSM (cell phone for the 5 years olds) converter on them. So while you dial 911 you are actually talking to a Forrest Ranger who's useing a handheld/truck two way radio.", "If there is no signal...it DOESN'T work If there is no sim card, it can still access the network, and any cell tower will patch through an emergency call, regardless of whether the phone has a sim, or account with anyone.", "Do emergency calls use the same amount of bandwidth as normal calls?", "FCC mandates that all phones be able to dial 911 (in the us) even if that phone is roaming or not activated with any carrier.", "Each cell company operates on only certain frequencies (Sprint: 800, 1900.. Verizon: 600, 1500... You get the idea). Most phones are capable of operating on most of those frequencies, hardware-wise. Emergency calls are able to be made on any band for safety purposes. As long as your phone can ping a tower, you can call 911.", "US and UK law (probably most other countries, but I can only attest to these) require cell towers, regardless of their networks, allow a device to connect and make emergency calls. So, imagine it like this. You're in a town filled with private clubs, and they all require a membership pass (reference: your sim card). But, if you're bleeding and require emergency medical attention, they're not allowed to turn you away. Regardless of if you're a member of their club, some other club, or no clubs at all. No signal, displayed in the GUI of your phone, doesn't mean there's \"absolutely no signal\", just that there are no cell towers that you are eligible to use. But, if you've got the slightest signal and try to make an emergency call, it will connect to the strongest signalling tower to make the call. If the cell tower is operating legally, they're in a rental contract with the appropriate government which states that they will allow, free of charge, calls to emergency numbers. However, there are places on Earth where you're completely out of signal (e.g. FAR out at sea, since there are sometimes cell towers covering a large distance from the coast for distress calls, and also in mountain regions, anywhere near military bases). In these places, you shouldn't be told you can make emergency calls. Edit: Some other things I forgot to mention... When your phone is running normally, it will have a soft limit as to how much power it's [the antenna] willing to expend to connect to a tower. Usually there's a hard limit of about 1 Watt, but this isn't universal (necessarily). But the soft limit, to preserve battery, will be lower; so if you're seeing \"Emergency Calls Only\", you could actually have a weak signal to your own carrier. The weaker the signal, the more power required to communicate with it effectively. So to preserve the power, it doesn't bother connecting to this eligible tower under normal circumstances, meaning you won't receive SMS messages or calls, and can't make them to non-emergency numbers. Whenever you make an emergency call in any country (in accordance with your phone/sim configuration), your phone's antenna begins using the full hard limit. It will establish and register with the strongest signals it can, and maximum priority is given to responding to the pings which are used to triangulate your location. This allows emergency operators to find you pretty much immediately - unlike in movies where it takes an arbitrary amount of time, it's actually a fraction of a second if you're connected to 3 towers in full accordance.", "Your cell is calibrated to let's say, Comcast. It will only detect Comcast signals, which if you are out of range, will not detect a Comcast signal. If you need an emergency call, your phone will use Verizon's network.", "Inside your cell phone there is a list called the PRL or *Programmable Roaming List*. The PRL list contains the list of cell towers you can use normally to make calls, get data, Etc. This list is frequently updated by your carrier. Cell sites in your PRL should recognized and permit your phone to log into it automatically. When a phone is in emergency call mode, it connects through the already connected cell site to complete the call. If it's got no bars and no PRL-listed site handy, it will use the strongest tower nearby it can talk to. If you are in the middle of nowhere with no bars, you will be lucky to be able to make any call - even an emergency one. As long as there's some carrier present though, emergency calls should be possible."], "text_urls": [[], [], [], ["https://books.google.com/ngrams/graph?content=irregardless&amp;year_start=1800&amp;year_end=2000&amp;corpus=15&amp;smoothing=3&amp;share=&amp;direct_url=t1%3B%2Cirregardless%3B%2Cc0#t1%3B%2Cirregardless%3B%2Cc1"], [], [], [], [], [], [], [], [], [], [], [], [], []], "score": [23876, 19167, 1702, 609, 221, 103, 70, 47, 30, 12, 10, 6, 6, 4, 4, 3, 3]}}, {"q_id": "7mbpxg", "category": "Repost", "title": "Why do people hear their voices differently when they speak vs. when they hear it played back on video or tape?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drsrxnj"], "text": ["When you speak, the sound is transmitted to your ears both through the air, and through the bones in your skull. When someone else hears you speak, they only hear the vibrations in the air. That's also the only thing a recording hears. Thus a recording accurately represents what you sound like to everyone but yourself."], "text_urls": [[]], "score": [3]}}, {"q_id": "7mdnnh", "category": "Repost", "title": "How does a diamond, the hardest substance on earth, still get shattered by a hydraulic press?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drt6jc4", "drt88tq", "drt74l3"], "text": ["Because it's just hardest, not toughest. It won't scratch easily, that's true. But hardness won't prevent it from turning into expensive dust once you apply enough pressure to it.", "Hardness, as an intrinsic property of a material is understandably important but it is also easiest to define (see Mho\u2019s scale of hardness); Other engineering properties however, such as Toughness and Strength, are not. On the Mho\u2019s scale, every subsequently harder type of material will \u2018scratch\u2019 all materials that are softer. The second hardest substance for example - Corundum, that sapphires are made of, can only be scratched with a piece of diamond (which makes it an excellent choice for \u2018sapphire-crystal\u2019 glass such as on a high end watch). But in most cases, hard materials are almost always \u2018Brittle\u2019. Brittleness of a material implies that it is susceptible to shattering - the way that glass shatters. A hard material may be resistant to \u2018scratching\u2019 at the surface level, but at the bulk level, instead of deforming when struck with enough force or put under sufficient stress (like under a press) will fracture into smaller pieces. The most appropriate example to demonstrate these properties (in fashion with diamond) would be steel (both are crystalline). Steel is also extremely versatile and can be heat treated to either be Hard & Brittle or Soft & Tough (also see malleability and ductility). As an engineered implementation, Japanese swords make use of both forms of steel because neither is desirable by itself (hard steel can hold a sharp edge but can easily shatter and break while softer steel might be tough and resilient but fails as a sword). TL;DR : Hardness is not the only notable physical aspect of a material. There are only other equally significant attributes like Toughness and Strength. (Titanium shakes head in neglect)", "Being hard and being *strong* are two very different things. Diamond is incredibly hard, and won't scratch, but it's also fairly brittle, because of how hard it is. It will break or shatter before it will bend or otherwise be able to withstand high pressures."], "text_urls": [[], [], []], "score": [15, 6, 4]}}, {"q_id": "7me3ld", "category": "Repost", "title": "How does salt and/or sand \u201cmelt\u201d snow?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drt97cr"], "text": ["Normal rain water freezes at 0\u00b0c. Salty water freezes at a lower temperature. As long as it's not cold enough to freeze salty water the ice melts. It's often laid as grit and or sand because salt is soluble, it melts the ice but then it dissolves and runs down the drains with the water. Grit and sand helps hold the salt in place and dissolve more slowly. Interestingly as the ice melts it ~~looses~~ loses energy and actually gets colder! Thats why it's important to grit before the paths and roads go icy to have the greatest effect *Edit typos*"], "text_urls": [[]], "score": [12]}}, {"q_id": "7mesl6", "category": "Repost", "title": "Why is it difficult to make a fist with your hand when you wake up first thing in the morning?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drtdnjz", "drtdkmg"], "text": ["Actually, if you put your mind to it, you can. Breathe a little bit and engage your entire upper body muscle, and you can. This means that the physical strength of your body has not degraded, but the readiness, or the mental reaction, hasn't kicked in yet. You've been asleep for a while so you wouldn't be ready to start running or grip with strength. Or, (not quite like sleep paralysis) your physical state and mental state aren't locked in together quite well yet Same reason why you can't flex your biceps or do pushups, or something. Let me give you an example: when I wake up every day at 7:15, I know that alarm is crucial, and I know that I need to stop the alarm fast ~~to drift to sleep~~to start getting busy. I jump right out of my bed because my muscle memory is triggered, not because of readiness to the environment", "You knuckles swell slightly over night. I often can't get my ring off first things in the morning either."], "text_urls": [[], []], "score": [12, 4]}}, {"q_id": "7mf052", "category": "Repost", "title": "Why are 11 and 12 eleven and twelve and not one-teen and two-teen", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drteo5w"], "text": ["There's nothing special about the number ten when you're an illiterate peasant in early medieval Europe. Yes the king's tax men use a base ten system, but they're using latin numerals and you can't count any higher than your fingers or knuckles can handle. Because of that, the common speech around numbers evolved somewhat arbitrarily in each language until enough people understood enough math to really start cementing and standardizing it. In English, the switch to systematic naming happens at 13. In Spanish, it's at 16."], "text_urls": [[]], "score": [3]}}, {"q_id": "7mg1b3", "category": "Repost", "title": "What is Dandruff? How do dandruff shampoos try to stop it?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drtmcze"], "text": ["Yer not alone in askin', and kind strangers have explained: 1. [ELI5 - Why does anti dandruff shampoo get rid of dandruff while other shampoo doesnt really? ]( URL_0 ) ^(_8 comments_) 1. [ELI5: What does Anti-Dandruff shampoo do that is different from regular shampoo? ]( URL_6 ) ^(_ > 100 comments_) 1. [ELI5: What is dandruff and how does pyrithione zinc (head and shoulders) stop it? ]( URL_4 ) ^(_19 comments_) 1. [ELI5: What makes a shampoo anti-dandruff? ]( URL_1 ) ^(_10 comments_) 1. [ELI5: The difference between dry scalp and dandruff. ]( URL_5 ) ^(_33 comments_) 1. [ELI5: How does anti dandruff shampoo specifically target dandruff? How is it different from regular shampoo? ]( URL_2 ) ^(_5 comments_) 1. [ELI5: Anti-dandruff shampoo ]( URL_3 ) ^(_4 comments_)"], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/vhdsm/eli5_why_does_anti_dandruff_shampoo_get_rid_of/", "https://www.reddit.com/r/explainlikeimfive/comments/6jrm50/eli5_what_makes_a_shampoo_antidandruff/", "https://www.reddit.com/r/explainlikeimfive/comments/43fztf/eli5_how_does_anti_dandruff_shampoo_specifically/", "https://www.reddit.com/r/explainlikeimfive/comments/1mnu20/eli5_antidandruff_shampoo/", "https://www.reddit.com/r/explainlikeimfive/comments/2kj09z/eli5_what_is_dandruff_and_how_does_pyrithione/", "https://www.reddit.com/r/explainlikeimfive/comments/3qqr4x/eli5_the_difference_between_dry_scalp_and_dandruff/", "https://www.reddit.com/r/explainlikeimfive/comments/3kfzjk/eli5_what_does_antidandruff_shampoo_do_that_is/"]], "score": [6]}}, {"q_id": "7mgb93", "category": "Repost", "title": "how do large companies buy other large companies? Who gets the money? What happens to the employees? Is every company for sale?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drtpfxl"], "text": ["When a company is buying another company, what they're doing is purchasing the stock of that company. The money goes to whoever owned that stock. So if you owned 10 shares of ABC corp and XYZ corp acquired ABC corp you'd be paid for your 10 shares at a fair price, or alternatively your shares would convert into X shares of XYZ corp. Nothing happens to the employees just because of an acquisition. All it means is that a different set of people own the company. In some cases those people acquired the company because the company was profitable, so they'll not change much in the company because it's working. Other times they acquire the company because it has something valuable (patents, buildings, etc.) but it's otherwise not that useful, so they may fire many of the employees. Companies get acquired when people representing a majority (or more) ownership agree to it. The terms of the agreement decide what happens next. If you own 51% of a company and you refuse to sell for any price then your company is not for sale. The reality is most people get ownership of companies to make money, so there's probably some price that's worth selling. In some cases, very big companies can only reasonably be acquired by other very large companies, and in those cases the government might step in and prevent the sale, since it would be harmful for customers and others if it went through."], "text_urls": [[]], "score": [3]}}, {"q_id": "7mkbej", "category": "Repost", "title": "How is antivenom made and why is snake venom beneficial for this process?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drun01n"], "text": ["This question gets asked a lot so please do a search next time but: antivenom works basically the same was as vaccines; you give your immune system a \"preview\" of whatever the vaccine is for. Not enough to make you sick, but enough for your body to produce antibodies that are ready to go. For antivenom, they use horses as an intermediary. They inject the horse with a tiny amount of diluted venom \"milked\" from a venomous animal. Not enough to sicken the horse, but enough for the horse's body to produce antibodies to the venom. Then they take a blood sample from the horse and remove everything else so only the antibodies remain, and that's the antivenom. Like vaccines, antivenom only works on the venom from the specific species or closely related species of the animal that it came from. In the same way a flu shot doesn't protect you from the measles, antivenom for a bite from a cobra won't help you against a bite from a venomous spider. That's why a lot of different antivenins exist for different species or groups of species of venomous animals."], "text_urls": [[]], "score": [3]}}, {"q_id": "7mkgzr", "category": "Repost", "title": "How did language split so drastically to the point that we have the vast amount of languages today?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["druo1pv", "druoh8w"], "text": ["Languages naturally drift. If you compare, say, American English today to how it was spoken 100 years ago, you will see noticeable differences in vocabulary, syntax, grammar, and pronunciation. Not so much that it can no longer be understood, but still quite significant. Even in recent years, things like dangling prepositions and using \"they\" as a gender-neutral singular pronoun have become acceptable. These differences were more pronounced it the past, before universal education and literacy, and when people were more isolated. With few central authorities declaring exactly how a language should be used and people rarely straying more than a day's walk from the village they were born in, they was very little to keep communities who spoke a given language synchronized, and in as little as a few centuries they could no longer be mutually understood.", "Very generally speaking, we do not precisely know. We use somewhat messy tools, like *statistical linguistics*, to sort of reverse-engineer our current languages' ancestors and estimate the geographical paths they took. two general postulates seem to be pretty popular right now, but they are not by any means certain or proven: * unlike biological life - where truly all living things on this globe may be traced back to a single common ancestor, and thus a single original burst of life from lifelessness - it is thought that language came about multiple times and that the \"family tree\" of human language may have multiple trunks. specifically, these trunks are the big language superfamilies like Indo-European (containing almost every language widely spoken between Alaska, Argentina, Greenland, the Urals, Bangladesh, and the Mediterranean, with the prominent exception of Uralic, the wildcard family that links Hungarian (Magyar) and Finnish, along with several others), Sino-Tibetan (a smaller East Asian family which nonetheless contains the world's most spoken first language, Mandarin Chinese), Afro-Asiatic (much of the Maghreb and wider Arabic-speaking world), and [many others]( URL_1 ). * Indo-European has received particular attention in the western world, as it is by far its most dominant and influential language family and cultural bias has granted it a preeminent status in acedemia. We think it maybe came from somewhere around southern Russia and the Caucasus republics, and [Proto-Indo-European]( URL_0 ) is the term for both that real language if it existed and our statistical guesses at what it sounded like, trying to work backward from later languages and our best knowledge of how sounds shift with time (flipped backwards). an interesting aside. Indo-Aryan is a sort of sister family to Indo-European which contains a commanding chunk of the many languages spoken in modern South Asia. this term had a broader, and wronger, meaning in the early 20th century, and it is thought possible that this early fumbling attempt at linguistic taxonomy was a major route for the previously-obscure term \"aryan\" into european languages such as English and German. Adolf Hitler, we know, erroneously conflated ethnicity and language (they are quite different, though interplay with each other) and it is from this series of deliberately poor understandings that a large part of Nazi racial doctrine arose. the moral of the story: the popular consensus is definitely not the proven fact of nature. do not ever kill people because of linguistics. killing people over orthography and grammar is frowned on."], "text_urls": [[], ["https://en.wikipedia.org/wiki/Proto-Indo-European_language", "https://en.wikipedia.org/wiki/Language_family#/media/File:Primary_Human_Language_Families_Map.png"]], "score": [7, 3]}}, {"q_id": "7mkzcf", "category": "Repost", "title": "what is the difference between a debit card and a credit card?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["druqm52"], "text": ["A debit card withdraws money out of your account right away. So you have $10, buy something worth $5, you have $5 remaining in your account. A credit card allows you to borrow money with interest to pay at a later time. So you have $10, put $5 on credit, and you still have $10 in your account. But at the end of the month, you'll have to pay back the $5 on credit with interest, so now you pay $5.25."], "text_urls": [[]], "score": [6]}}, {"q_id": "7ml8nz", "category": "Repost", "title": "why is it when we stretch our hearing gets muffled?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drutdlb"], "text": ["Because most of the time you will open your mouth at the maximum to yawn and tighten a lots of muscles around your eyes. The muscle, tendon and skin will tighten and will slightly increase the tension in your eardrum. That extra tension make the ear drum less sensitive and the sound will feel muffled. If you can successfully stretch yourself without yawning you will see no change in your hearing"], "text_urls": [[]], "score": [3]}}, {"q_id": "7mlwx8", "category": "Repost", "title": "how do refrigerators work. Like how do they make things cold", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["druw9mk"], "text": ["1. The compressor constricts the refrigerant vapor, raising its pressure, and pushes it into the coils on the outside of the refrigerator. 2. When the hot gas in the coils meets the cooler air temperature of the kitchen, it becomes a liquid. 3. Now in liquid form at high pressure, the refrigerant cools down as it flows into the coils inside the freezer and the fridge. 4. The refrigerant absorbs the heat inside the fridge, cooling down the air. 5. Last, the refrigerant evaporates to a gas, then flows back to the compressor, where the cycle starts all over."], "text_urls": [[]], "score": [5]}}, {"q_id": "7mngch", "category": "Repost", "title": "How does a \u201ccitizen\u2019s arrest\u201d work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drv7pvf", "drv7xfn", "drv7qlj"], "text": ["> Do different states have different rules regarding when/where/who/why you can do this? Yes, which makes answering your other questions hard since it is going to vary by state. For example, in California, you can perform a citizen's arrest under these circumstances * For a public offense committed or attempted in his/her presence. * When the person arrested has committed a felony, although not in his presence. * When a felony has been in fact committed, and he or she has reasonable cause for believing the person arrested to have committed it.", "Laws vary by jurisdiction. In Canada, this is known as a section 494 arrest, and while it can technically be effected by anyone, its purpose is really to empower e.g. security personnel who are not actually law enforcement or officers of the court to make arrest and detention prior to transfer of custody. To be valid, you must personally witness someone **in the act** of committing an indictable offense (analogous to US felony: assault, including assault by trespass, theft over $5000, narcotics trafficking, etc.), inform the person that they are being arrested and why, and inform them of their Charter rights (US Miranda warning). An arrest under .494 cannot be made for summary conviction offenses (US misdemeanors), and any use of force applied to effect an arrest and detention must be reasonable and necessary. Security officers may need to be licensed by their province to act in this capacity, and may need to be separately endorsed to use restraints (handcuffs).", "Chances are, you\u2019re gonna get yourself into trouble if you attempt a citizen\u2019s arrest. You can restrain someone until the police arrive if you are preventing harm to yourself or others. But in almost every other situation, you\u2019re opening yourself up to lawsuits. Not mention scrutiny from the arresting officers."], "text_urls": [[], [], []], "score": [21, 11, 7]}}, {"q_id": "7mnlb0", "category": "Repost", "title": "Why does boiling water turn to snow when thrown in extreme cold temperatures and cold water doesn't?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drva5vj"], "text": ["[This]( URL_0 ) is a pretty decent explanation of it. Basically, the water isn't actually turning into snow, but evaporating and then very quickly condensing into a cloud. Near-boiling water is very near to its evaporation point. When you throw it into the air (any temperature air), some of the water will vaporize due the elimination of cohesive force of adjacent water molecules. For an instant you have a bunch of steam in the air. Now when you do this in very cold air, the steam then cools rapidly and condenses back into water vapor, creating a cloud."], "text_urls": [["http://thevane.gawker.com/the-science-behind-turning-boiling-water-into-snow-on-1678181346"]], "score": [15]}}, {"q_id": "7mov1x", "category": "Repost", "title": "What happens in a cpu that causes it to generate heat?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drvitk9"], "text": ["Computations take electrical energy to work. Energy can't be created or destroyed, it can only be converted from one form to another. The electrical energy gets converted to thermal energy by the processor as a consequence of performing the computation."], "text_urls": [[]], "score": [4]}}, {"q_id": "7mqqgy", "category": "Repost", "title": "When you have a stuffed nose, why is it that one nostril is always blocked/more blocked", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drvy9ji"], "text": ["Importantly, the blockage is not \"stuff\" (like mucus/snot) that's clogging up the nostril; it's the lining of the nose swelling up and closing off the airway. There are two important facts to know about blocked noses: 1. There's something called the \"nasal cycle\" that occurs normally, where the mucus membrane in your nostrils swells slightly, alternating between nostrils throughout the day. This happens all the time, every day, but isn't severe enough to really be noticeable. 2. When you have a cold, the mucus membranes in *both* nostrils swell slightly as part of your body's immune response. When you combine the two, the nostril that's normally slightly swollen from the nasal cycle gets even *more* swollen because of the cold, and that nostril swells shut. That's why blowing your nose doesn't fix it (it's not blocked by anything that can be blown out), why it switches nostrils occasionally (the nasal cycles changes which nostril is swollen more than the other), and why nose drops don't completely fix the issue (they can't completely eliminate the extra swelling from having a cold)."], "text_urls": [[]], "score": [7]}}, {"q_id": "7mrx7o", "category": "Repost", "title": "How does the camouflage skin of Octopi, Squid, and Cuddlefish match their surrounding color and texture so accurately?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drwjudz"], "text": ["They have highly specialized cells that get a signal from the brain when it detects a certain surrounding colour and then expand or contract in order to change the pigment in the cells. You can notice that they\u2019re never fully campouphlaged but only partly and being under water helps them become \u2018invisible\u2019. Due to lack of time I\u2019ll post a link here: URL_0"], "text_urls": [["https://www.google.nl/amp/ocean.si.edu/ocean-news/how-octopuses-and-squids-change-color%3famp"]], "score": [3]}}, {"q_id": "7mtcnm", "category": "Repost", "title": "Why does Horizon Organic milk last so much longer than normal milk?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drwijbn", "drwihnl"], "text": ["It has been \"ultra pasteurized\", meaning it has been processed by heating it to a high temperature longer than normal milk. This will increase its shelf life while imparting a somewhat \"burn\" flavor which those unfamiliar with it can find off-putting. It doesn't really have anything to do with it being \"organic\", other than that organic producers are not as common so the milk needs to travel a longer distance before being consumed so the longer shelf life is desirable. So in summary it is because it is old burnt milk.", "Milk, fresh from the cow, spoils fairly quickly because there's naturally occurring microorganisms that like to \"eat\" it. Normal milk is *pasteurized*. That means it's briefly heated to high temperatures to kill the microorganisms. The downside is that this slightly changes the flavor but nobody notices anymore because nearly all milk is pasteurized. The organic milk you find in the store is often [ultra-high-temperature (UHT) pasteurized]( URL_0 ) to kill off *even more* of the microorganisms and make it last even longer. The downside is that this impacts the flavor even more but since organic milk is a niche product it needs to be done. There are fewer producers of organic milk so it often needs to be shipped further & there are fewer consumers so it often sits on the shelves longer before being sold, so it must have a longer shelf-life to be a feasible product."], "text_urls": [[], ["https://en.wikipedia.org/wiki/Ultra-high-temperature_processing"]], "score": [13, 10]}}, {"q_id": "7mtfo7", "category": "Repost", "title": "How does Anti-Dandruff Shampoo work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drwj366", "drwj3rh", "drwqesj"], "text": ["When i took a class on fungi in college the professor told us that the secret to Head and Shoulders or any similar dandruff shampoo is that it is actually a fungicide. The dead skin flakes from your scalp are acually held together by a fungus and by killing it with the shampoo the dandruff flakes break apart into smaller pieces. So really by using the shampoo you're not eliminating your dandruff all together but making the dead skin flakes small enough so they're not noticeable. Plus I'm sure there are some moisturizers and what not in it also to help hydrate your scalp.", "If my understanding is correct, dandruff is caused by an imbalance in a yeast production in the skin called seborrheic dermatitis. The active ingredient curbs the yeast production reducing the itchy flaky skin.", "Pro-tip: Sometimes \u201canti-dandruff\u201d shampoo doesn\u2019t work. If you\u2019ve only got flakes but not as much of an itchy scalp, then give it a whirl! But, if your head feels dry as a Londoner\u2019s humor with an itch you just can\u2019t scratch, then you should try shampoo specifically for moisturizing dry scalps. The active ingredient in standard Head and Shoulders can cause a person with dry scalp to itch more, resulting in more flakes. (OH THE HUMANITY!) Source: A guy who learned that lesson and never looked back at his shoulders again."], "text_urls": [[], [], []], "score": [24, 7, 7]}}, {"q_id": "7mu3ko", "category": "Repost", "title": "How does the television show \u201cPlanet Earth\u201d film without disturbing the wildlife?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drwnca5", "drwnekk"], "text": ["With patience, very high quality cameras with powerful zooms, camouflaged bunkers, and careful shot selection. You don\u2019t see the thousands of hours of completely useless footage they get", "After finding a group of animals to film, filmmakers will analyze the best places to film from and they may have to wait for days, even weeks, to get the shot they want. This is especially the case for migratory filming where they may have to stay put and wait for a single opportunity to present itself. This is one of the reasons major documentaries like PE take so long to film. The filmmakers are literally in and out of the field for years capturing wild life video."], "text_urls": [[], []], "score": [11, 5]}}, {"q_id": "7mue54", "category": "Repost", "title": "Why is laughter contagious?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drwq0ev", "drwqcv0"], "text": ["Because your brain is wired to react to social cues. These reactions, like joining in a laugh, are survival traits for social animals. To survive as part of a group, empathic behavior is mandatory, it sets in-group/out-group dynamics and group cohesion.", "There are a few theories about why we laugh. But i don't think there is any general consensus. One theory is that we laugh when we realize a situation isn't what we expected it to be. Especially when we though a situation would be dangerous but its actually not dangerous. I.e. You got scared because you though you saw a snake, but its only a tree branch. Hahaha. So its contagious then to help spread the message. Everything is okay, things are not the way they initially appeared. We also laugh in a lot of social situations. If things get tense between two people in a group, one person laughs, the whole group laughs, things are now less tense. We're saying this is not a serious situation. Take it easy. The general answer is that laughter communicates a socials message, and when the group wants to re-enforce that message, the whole group laughs. Its sometimes not contagious, like when you laugh at the wrong time. Nobody else laughs because they are taking it seriously. Then you feel shitty."], "text_urls": [[], []], "score": [21, 10]}}, {"q_id": "7mul7v", "category": "Repost", "title": "How do carnivores like Tigers and Lions get enough nutrient balance by only eating meat?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drwr2p5"], "text": ["One, By eating things like blood, skin, organs, bones, etc. Obviously that animal they ate *contains all vitamins and minerals required for that prey animal to live* so consuming all, or most, of a prey animal will include a wider variety of vitamins and nutrients. Humans can do this too, for example fish liver oil, whale blubber etc,. Whale blubber contains high amounts of vitamin C. Two, Different animals have different dietary needs. We primates require Vitamin C in our diets but we can manufacture other vitamins , many other mammals, including cats and dogs, *can actually synthesize their own vitamin C* so it isn't a dietary requirement. Cats require vitamin A from animal sources, they cannot process carotenoids(from plants) into vitamin A. Dogs, and us, can eat a carrot and make vitamin A. Different animals have different needs and different capabilities to manufacture vitamins or to dietary input into essential compounds."], "text_urls": [[]], "score": [9]}}, {"q_id": "7muw7j", "category": "Repost", "title": "Occam's Razor", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drwttr9", "drwv7qq", "drwsyx8"], "text": ["You go to your room and find a new large purple stain on your bed. Your sibling is standing next to your bed holding a cup that has the remnants of grape juice in it. However, you now remember that your parents recently painted the basement walls purple. Could some of that paint somehow gotten on to your bed and created the stain? Sure, but the simpler explanation is that your sibling spilled the grape juice. This principle, of going with the simpler explanation, is Occam's Razor.", "The traditional Occam's Razor example is \"When you hear hoofbeats, think of horses not zebras\" In most places the chances of you encountering a horse are far larger than the chances of encountering a zebra so if you think horse you are far more likely to be correct about the source of the hoofbeats. A choice of zebra implies that someone went, picked up some zebras from Africa, shipped them to whereever you are, and set them loose. That's a lot more steps than a mounted police officer or horse from nearby farm is coming. The answer with the fewest assumptions is most likely to be right and should be the one you pick", "In essence, Occam's Razor is a kind of rule of thumb to take the simplest explanation when multiple are given."], "text_urls": [[], [], []], "score": [45, 14, 12]}}, {"q_id": "7muygi", "category": "Repost", "title": "The heat death of the universe", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drwtgx0"], "text": ["The universe is expanding. The volume of the universe is increasing, and the amount of usable energy is decreasing (entropy is increasing). Eventually, the universe will expand so much that no particle will ever interact with any other particle again. The universe will be 0 Kelvin, and completely dead."], "text_urls": [[]], "score": [9]}}, {"q_id": "7mvu80", "category": "Repost", "title": "Why does ice cream not melt when being deep fried?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drx2rty"], "text": ["It's only deep-fried for about 10 seconds which isn't enough time for the heat to reach anywhere but the surface."], "text_urls": [[]], "score": [3]}}, {"q_id": "7mw6j0", "category": "Repost", "title": "what is entropy?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drx7555"], "text": ["You're going to get a lot of people telling you that entropy is like 'disorder', but I think that's a poor analogy. Entropy tends to lead to things breaking into smaller pieces and mixing together. While this can appear disorderly at first, it will ultimately lead to something that looks extremely ordered. So if not disorder, then what? Personally, I like to look at the original engineering definition of entropy for guidance. Such a definition might read: \"Entropy is a measure of the energy in a system that cannot be made to do useful work, normalized by the temperature\". If we look at the temperature as an indicator of the thermal energy, then entropy is a ratio that indicates how easily the energy in a system can be made to do something. So a system with high energy and high entropy can't be made to move things very well, despite having a lot of energy. Similarly, a system with low energy and low entropy can be made to move things fairly easily, but won't move them very much. In a word, this is laziness. Entropy is a measure of the laziness of a system, and the second law of thermodynamics says that a closed system will only become lazier with time. Here's a few examples of how you can visualize this. Children are high energy, low entropy: they often move around a lot no matter how you try to restrain them. Teenagers are high energy, high entropy: they have the energy to accomplish a lot, but you would have a hard time convincing them to move. Retirees are often low energy, low entropy: they seem to be constantly on the move, but they move very slowly, and take frequent naps to recharge. TL;DR: Entropy is laziness."], "text_urls": [[]], "score": [3]}}, {"q_id": "7mxhgf", "category": "Repost", "title": "How do shows like The Grand Tour get away with obvious speeding on public roads all over the world?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drxemfw"], "text": ["You go through a shitload of paperwork and permits to shoot a television show. Meanwhile the \"magic of television\" means that say it's an open public road, but in all likelihood traffic is being controlled in the areas where they're shooting. It's really no different to get a permit to speed, than it is to get a permit to set off massive amounts of explosives for a visual effects shots."], "text_urls": [[]], "score": [6]}}, {"q_id": "7mxnsb", "category": "Repost", "title": "When there is heavy snowfall, why does it sound so quiet outside?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drxg8lb"], "text": ["Snow is an excellent insulator. So many crags and crannies redirecting sound waves end up nullifying the random ambient sounds."], "text_urls": [[]], "score": [3]}}, {"q_id": "7myeaj", "category": "Repost", "title": "Hot vs Cold water wash", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drxs54c"], "text": ["Hot water has more energy to allow compounds to dissolve (and it also increases the rate at which dissolving occurs). The heat can break bonds between the stain and the object it is adhered to (like food on a plate) and the water also has more molecules with enough energy to form the bonds required to dissolve the particles. Proteins are usually easier to clean with cold water (like blood stains on clothing) due to the hot water denaturing the protein and making it adhere to objects (especially clothing) more. Detergents and washing powders that utilise enzymes will not work with hot water, as they are also composed of proteins which will denature and not work."], "text_urls": [[]], "score": [5]}}, {"q_id": "7mygqq", "category": "Repost", "title": "How are underwater tunnels made without flooding and killing the workers?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drxnqiv", "drxpxhn"], "text": ["They don't build the tunnel through the water, they dig *under* the rock that's under the water. [Here is a diagram]( URL_0 ) so you can see what it looks like.", "The tunnel is bored into the material (rock/clay/sand/etc) that is below the bottom of the body of water. As the machine digs, 2 things happen. First, the area that is directly being bored through is sealed off from the area behind it (where the machine has been) and is pressurized. You know how an airplane is pressurized? Same sort of thing. In this case, the pressure is high enough to keep the water out of the tunnel...or most of it. As the machine moves ahead, the second thing happens. Large sections of concrete (curved to fit the hole) are attached. This both stops the tunnel from caving in, and holds back the water. The machine then moves ahead and repeats the process. Some machines have the ability to pump material ahead of the cutter to fill the cracks in the rock to stop the water from coming in. Another method involves building the full tunnel section on land. Both ends are sealed, and the section is floated out. When over the right spot, the section is partially flooded with water. It sinks, and then is connected by divers to the previous section. At that point, one end is unsealed, the water is pumped out, and then the process is repeated. This tunnel ends up *on top* of the sea/river/lake floor. It's then covered by fill to protect it."], "text_urls": [["https://upload.wikimedia.org/wikipedia/commons/thumb/3/36/Seikan_Tunnel_profile_diagram.svg/800px-Seikan_Tunnel_profile_diagram.svg.png"], []], "score": [9, 4]}}, {"q_id": "7myob4", "category": "Repost", "title": "What is the difference between my 5GHz wifi vs. my 2.4GHz wifi?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drxoh8k"], "text": ["1. Frequency. One operates at ~5Ghz, one operates at ~2.4Ghz 2. Interference. More non-wifi (802.11b/g to be specific) devices utilize the 2.4ghz spectrum/generate radio waves at this spectrum, such as old portable phones, microwaves, bluetooth, etc. 3. Range, speed, and penetration. 5Ghz (802.11ac and 5Ghz n, to be specific) wifi has superior speed, however the range and ability to penetrate solid matter such as walls is inferior to 2.4Ghz wifi."], "text_urls": [[]], "score": [9]}}, {"q_id": "7n0jdu", "category": "Repost", "title": "what is computation, and how does brain compute?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dry41bj"], "text": ["Basically, computational theory of mind is the idea that your brain works like a computer does; information goes in, programs are run on it, and information goes out. In a computer, the stuff going in is strokes on a keyboard or mouse movements. The programs are... programs... and the stuff going out would be what's on the screen or what you print. In a brain, the input is the sight, smell, taste, sounds... everything your senses tell you. The output is your words and actions. The programming between the input and the output is what we're still learning. Because we can't watch a brain working (though fMRIs are making this a bit easier), and we can't read the source code for the brain, we learn what it's doing the same way we can learn what a program does; putting things in and seeing what comes out."], "text_urls": [[]], "score": [4]}}, {"q_id": "7n1f43", "category": "Repost", "title": "Why is it that extremely cold things can feel hot and vice versa?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drya465", "dryhd9x"], "text": ["To the molecules in your hands, feeling something cold is like being in a car that's slowing down and feeling something hot is like being in a car that is speeding up. But feeling something really hot is like being hit by a car and feeling something really cold is like hitting parked car. Either way you crash and it feels similar.", "When you feel something sort of cold or sort of hot, your nerves tell your brain that it's cold or hot. When you feel something way too hot or way too cold, the only thing your nerves tell your brain is, \"Ouch, don't touch that!\" At that point your brain can't tell what temperature it is, only that it's dangerous, so it sort of guesses."], "text_urls": [[], []], "score": [35, 26]}}, {"q_id": "7n4nwd", "category": "Repost", "title": "How crypto currencies fluctuate in price", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drz0h1w"], "text": ["You can think of crypto currencies just as any other finite good or asset: its price is determined by supply and demand which are also influenced by its scarcity. People buy bitcoins or other crypto currencies for different reasons: some do because they believe its price will rise in the future and they will be able to sell it with a profit, others do because they prefer to use them for financial transactions instead of \"real\" currencies. People sell crypto currencies because they want to have \"real\" money instead or because they exchange it for goods. The more people use a crypto currency for buying real goods (instead of exchanging it for \"real money\"), the higher the value of the currency and the higher the price (in terms of dollar) of the currency (and vice versa). This is because the value of a given currency is determined by how likely it is that someone will accept it as payment. This is the difference to goods: while they are consumed, currencies are used to exchange them again for other goods in the future. So as more and more people accept a given crypto currency, more and more people will also want to own it as they will be able to exchange them for other goods with people who accept the crypto currency. However, the massive fluctuations of crypto currencies (as opposed to general trends over time) are largely caused by speculation, i.e. by traders who buy and sell the currency in order to profit from price differences over time. In this regard a crypto currency can be seen as any other financial asset. However, there is one important difference to other goods and assets: bubbles that are intentionally created by a single actor or a small group of people who spread rumors online that the price of a particular crypto currency is going to rise in the hope that many people will follow the advice and buy that crypto currency. They then sell a lot of that crypto currency which they had acquired before spreading the rumor, thereby making a lot of money. As a consequence the price of the crypto currency falls dramatically (as the one who spread the rumor sold a lot at once)."], "text_urls": [[]], "score": [3]}}, {"q_id": "7n7k77", "category": "Repost", "title": "Internet cookies?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drzofow", "drzp3ae"], "text": ["Imagine you're reading a book. You're at a specific part of the book, somewhere in the middle. You decide \"that's enough book for today\" and you close the book. Next time you open your book, you're going to have to flip through all those pages again and manually find your page. Rather than having to remember what page you're on, why not just have the book remember for you? So you decide to put a bookmark in the book. You can also write down little notes on this bookmark, like \"This character just did this\" so that next time you open the book you can easily remember what you just read and pick up exactly where you left off. Cookies are essentially bits of data that websites leave in your browser so that they can quickly easily access them next time you visit. For example, if you sign into Facebook and say \"Remember Me\", Facebook leaves a cookie that remembers that you logged in on this machine and that you want to be logged in automatically in the future.", "Yarr! Yer not alone in askin', and kind strangers have explained: 1. [ELI5: How does internet cookies work, exactly? ]( URL_7 ) ^(_9 comments_) 1. [ELI5 what internet cookies are. ]( URL_4 ) ^(_2 comments_) 1. [ELI5: What are (internet) cookies and why am I supposed to clear them periodically? ]( URL_2 ) ^(_8 comments_) 1. [ELI5: What are internet cookies? ]( URL_1 ) ^(_4 comments_) 1. [ELI5: what actually are internet cookies, what do they do and why are they called 'cookies'? ]( URL_5 ) ^(_2 comments_) 1. [ELI5: What are internet cookies? ]( URL_3 ) ^(_7 comments_) 1. [ELI5: What exactly is a \"cookie/s\" when it comes to the internet? ]( URL_0 ) ^(_7 comments_) 1. [ELI5:Why are cookies (as in the things that track your internet history) called cookies? ]( URL_8 ) ^(_4 comments_) 1. [ELI5: What exactly are \"cookies\" in regards to internet browsing history? ]( URL_6 ) ^(_2 comments_)"], "text_urls": [[], ["https://www.reddit.com/r/explainlikeimfive/comments/3p3b4j/eli5_what_exactly_is_a_cookies_when_it_comes_to/", "https://www.reddit.com/r/explainlikeimfive/comments/1iifkq/eli5_what_are_internet_cookies/", "https://www.reddit.com/r/explainlikeimfive/comments/x1olr/eli5_what_are_internet_cookies_and_why_am_i/", "https://www.reddit.com/r/explainlikeimfive/comments/1i6lc2/eli5_what_are_internet_cookies/", "https://www.reddit.com/r/explainlikeimfive/comments/145xfm/eli5_what_internet_cookies_are/", "https://www.reddit.com/r/explainlikeimfive/comments/2augbg/eli5_what_actually_are_internet_cookies_what_do/", "https://www.reddit.com/r/explainlikeimfive/comments/1nx6u4/eli5_what_exactly_are_cookies_in_regards_to/", "https://www.reddit.com/r/explainlikeimfive/comments/3wp0i2/eli5_how_does_internet_cookies_work_exactly/", "https://www.reddit.com/r/explainlikeimfive/comments/73071d/eli5why_are_cookies_as_in_the_things_that_track/"]], "score": [9, 4]}}, {"q_id": "7n7ncu", "category": "Repost", "title": "why ice in a beverage stays in the same position when the glass is turned.", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drzpmv7", "drzoq0g"], "text": ["Newton's First Law of Motion states that an object at rest tends to stay at rest unless acted upon by an outside force, and an object in motion tends to stay in motion unless acted upon an outside force. So you have ice floating in a liquid in a glass. Ice has a low coefficient of friction, meaning it's slippery. So when you turn the glass, there is very little rotational force along the interface between the ice/liquid and the glass. So given this lack of force, the ice will tend to stay where it is.", "Because Ice doesnt care about anything its not touching. A fluid will always arrange itself by density if nothing else acts on it, so the denser part will be on the bottom. The fluid didn\u2019t move so the ice wont either, all they care about is gravity."], "text_urls": [[], []], "score": [10, 4]}}, {"q_id": "7n7pld", "category": "Repost", "title": "What is the difference between Microprocessors found in Smartphone (Snapdragon, Apple) and in PC/mac (Intel, AMD)?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drzozrr", "drzqh2w"], "text": ["Speed and power consumption. But, at the end of the day it's all about 1's and 0's. Also, I had to edit this because the auto mod said it wasn't sufficiently long enough so hopefully this is long enough now because not everything needs a big explanation. But, just incase... Both computers and smartphones are marketed heavily by their processor, and while the function is the same \u2013 both allow the individual devices to work \u2013 there are two major differences: When processors run they generate heat. Lots of heat. Because mobile devices are considerably smaller than computers, the heat generated by a running mobile processor is often amplified and can seriously harm components, or even melt them. Therefore, the developers and designers of the devices limit, or throttle, the speed at which a mobile processor can run. This means that if a processor is getting hot, it will limit its speed, which equates to slower performance. Because of this throttling, the processor on many phones will actually run slower than the advertised speed. In fact, the advertised speed of mobile processors is normally the maximum. Compare this to most computer processors, where the advertised speed is usually the average running speed, and you begin to see why computers are more powerful. The second big difference is connected with performance. If you take a computer and compare it to a mobile device with the same speed of processor, the computer will usually be able to do more. This is because the processor is limited in what it can do by the other hardware components, like the RAM, Graphics Processing Unit, etc. Computers have more space, so they can fit more advanced components, and are consequently able to do more. That being said, processor and other mobile technology is advancing at a blistering pace and it is highly likely that mobile hardware will continue to increase in overall power, and eventually be able to compete more effectively with larger computers.", "Yo ho ho! Yer not alone in askin', and kind strangers have explained: 1. [ELI5: What is the difference between Processor of a mobile phone and Desktop computer? And, how does it bring a change in performance to an end-user? ]( URL_4 ) ^(_11 comments_) 1. [ELI5: Why is it my phones processor is better than my laptops processor, yet my laptop is still faster (details inside)? ]( URL_2 ) ^(_4 comments_) 1. [ELI5: how are the processor of phones compared to PC's? ]( URL_1 ) ^(_5 comments_) 1. [ELI5: Smartphone CPUs, compared to PC ones ]( URL_0 ) ^(_6 comments_) 1. [ELI5: if Samsung make good processors for iPhone, why can't they make good processors for Samsung phones? ]( URL_3 ) ^(_10 comments_)"], "text_urls": [[], ["https://www.reddit.com/r/explainlikeimfive/comments/5qw1o3/eli5_smartphone_cpus_compared_to_pc_ones/", "https://www.reddit.com/r/explainlikeimfive/comments/33cakb/eli5_how_are_the_processor_of_phones_compared_to/", "https://www.reddit.com/r/explainlikeimfive/comments/3b86xi/eli5_why_is_it_my_phones_processor_is_better_than/", "https://www.reddit.com/r/explainlikeimfive/comments/529488/eli5_if_samsung_make_good_processors_for_iphone/", "https://www.reddit.com/r/explainlikeimfive/comments/3xy6d6/eli5_what_is_the_difference_between_processor_of/"]], "score": [7, 3]}}, {"q_id": "7n7spl", "category": "Repost", "title": "Given the sheer volume of snowflakes, isn't it statistically unlikely that they will be unique, even with all the possible permutations?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["drzpkp2"], "text": ["Ahoy, matey! Yer not alone in askin', and kind strangers have explained: 1. [ELI5: How do we know all snowflakes are unique, maybe there's such a large variety of them that it just seems that way. ]( URL_0 ) ^(_5 comments_) 1. [ELI5:How can EVERY snow flake be unique? ]( URL_2 ) ^(_17 comments_) 1. [ELI5: How do we know that two identical snowflakes have never existed and never will? ]( URL_5 ) ^(_20 comments_) 1. [ELI5: How can every snowflake be unique? And furthermore how do we know? ]( URL_6 ) ^(_2 comments_) 1. [ELI5: How Do We Know That Every Snowflake Is Different? There Are So Many, And They Melt Whenever They Touch Something Remotely Warmer Than Them. ]( URL_1 ) ^(_4 comments_) 1. [ELI5: Why does every snowflake have a different patten? ]( URL_4 ) ^(_2 comments_) 1. [ELI5:Why are snowflakes supposed to be unique? ]( URL_3 ) ^(_6 comments_)"], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/5skfm8/eli5_how_do_we_know_all_snowflakes_are_unique/", "https://www.reddit.com/r/explainlikeimfive/comments/3e5qs9/eli5_how_do_we_know_that_every_snowflake_is/", "https://www.reddit.com/r/explainlikeimfive/comments/1xmh0k/eli5how_can_every_snow_flake_be_unique/", "https://www.reddit.com/r/explainlikeimfive/comments/nihkg/eli5why_are_snowflakes_supposed_to_be_unique/", "https://www.reddit.com/r/explainlikeimfive/comments/5j53na/eli5_why_does_every_snowflake_have_a_different/", "https://www.reddit.com/r/explainlikeimfive/comments/7m6z1g/eli5_how_do_we_know_that_two_identical_snowflakes/", "https://www.reddit.com/r/explainlikeimfive/comments/3ygqev/eli5_how_can_every_snowflake_be_unique_and/"]], "score": [5]}}, {"q_id": "7n9v5e", "category": "Repost", "title": "why does the human body go into a \"coma\" and what is the body doing during this period?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ds0d7jh", "ds0dhvz", "ds0yyil"], "text": ["At the most basic level the body is prioritizing the immediate tasks needed to stay alive (keeping the heart beating & breathing) at the expense of more advanced stuff like processing stimuli and thinking. Comas can happen for a variety of reasons (trauma & infections being the main ones) and can be induced by medical professionals to keep the body focused on repair when it might not have the resources to both fix itself and fully function. Edit: Medically induced comas are also used to minimize psychological trauma which might result from being semiconscious while intubated (tube down your throat to your lungs to handle breathing); it\u2019s not a pleasant time. Edit: There\u2019s a variety of different awareness states & pain relief goals that can be targeted by a provider, which range from local anesthesia where a patient is conscious with a specific spot numbed to general anesthesia where a patient is fully unconscious & unresponsive to stimulus. The approach is dictated by the patient\u2019s particular presentation, history, & the goal of treatment. If you\u2019re interested in how a \u201ccoma\u201d is defined clinically (in treatment like a hospital), you can look at the \u201cGlasgow Coma Scale\u201d which provides gradiations of consciousness depending on patient presentation. There\u2019s a lot that needs to go wrong to put someone into a comatose state as the body is pretty resilient to outside changes. But if stressed, the body is structured to protect heart & brain function, at the expense of other parts of the body. For example, when cold, the body will constrict blood vessels far from the core (fingers, toes, etc) which saves heat and blood for important organs. The body can do this successfully because some tissues are more tolerant of being deprived than others, the use of tourniquets for bleeding is a great example. Tourniquets are used to stop massive blood loss on a limb (leg or arm), and when applied correctly, completely cut off blood flow. If you did this to a brain, it would be begin to take damage and die in a matter of minutes, but the limbs can be cut off from blood completely for several hours without tissue death. A coma is where the body has so few resources that it prioritizes basic functions (heartbeat and maybe breathing if it can be managed) but can\u2019t do anything else. These base functions are typically the last to go before death. The heart runs on an internal pacemaker, so even if the connection between the brain and the heart fails the heart continues to beat. You need signals from your brain to breath, but in a hospital setting that can be managed by a machine if your body won\u2019t do it.", "Since this is ELI5, there are many factors that can cause coma, but lets simplify: Brain damage, your brain is like a computer, sometimes circuits can be rerouted and that takes time so your brain has to shut down for a while to do this work. Thankfully, most basic functions to stay alive are automatic, things like breathing and heart beating, even digestion despite the fact that you can't feed yourself. This can happen from a seizure, an impact, infection, lack of oxygen, stroke, or other problems. Self preservation, some events can cause so much damage to the body that continued function would lead to death, as a product of evolution designed to survive, your brain can turn you off to take time to perform repairs and try its best to keep you from dying. This can happen from overdoses, chemical imbalances, even poor nutrition causing nervous system malfunction. For adults wanting a little more depth than a five-year-old; Hyponatremia, hypoglycemia, and diabetes are all common causes of coma.", "I'd like to ask a follow up question on this. Why is it that some comas last for several years, decades or even forever, long after any damage has been fixed? Does the body not have enough control to wake you up again? And why can't we medically wake someone up?"], "text_urls": [[], [], []], "score": [791, 76, 23]}}, {"q_id": "5re01q", "category": "Repost", "title": "Why is it that when my internet connection is poor, whatever video/stream I am watching lags terribly, while the advertisements before it are perfect quality?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dd6o8qg", "dd6iunt", "dd6j63v", "dd6my7b", "dd6jmm2"], "text": ["Ads are programmed by your site, often even regardless of what you're watching. Youtube essentially knows you're a techie guy and will start preloading techie ads before you ever get to actually watch any. That way, then it comes to showing you an advert, it will often just play one that it already locally downloaded to your buffer. This is a common technique that anyone who's worked with mobile apps and games is familiar with. Most advertising networks provide preload functions, and ways to check whether your ad has loaded. In short: your video is streamed, but your ads are downloaded before they play.", "The programming is delivered at a variable bitrate. If your connection is slow, your program stream switches to a lowered quality in an attempt to keep it flowing. Advertisers do not want to pay for their beautiful commercials to be displayed at that crappy quality, so they insist on being displayed at highest quality, regardless of whether it causes a bottleneck or not. Source: commercial producer for a major cable company(sorry...)", "If you're referring to web commercials, it's because they're highly compressed and tend to be loaded before your video even begins to buffer", "Adverts are short and don't play until the whole thing is ready. Films are streaming and if your internet is slow it drops the quality in preference to pausing while it buffers.", "It's the other way around with 70Mbps Virgin Media connection in the UK - ads take an annoyingly long time to load (which means it takes longer until I can skip them) then the video loads straight away. I assume it's because they are big enough to have worked out their own routing and caching with YouTube but don't use it on the adverts."], "text_urls": [[], [], [], [], []], "score": [29, 26, 4, 3, 3]}}, {"q_id": "5rey1d", "category": "Repost", "title": "How comes the universe is flat?", "title_urls": {"url": []}, "selftext": "I read it everywhere lately. 2D universe, holographic world, etcetc... But didn't find any explanation. D: Is this a legit theory at all? I mean like compared to hypertorus, for example. Also how this 2D universe comes together with string theory, or with any other popular theory? Thanks for the answers.", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dd6r1n4"], "text": ["You are mixing different concepts here. When cosmologists say \"the universe is flat\", it has nothing to do with the number of dimensions. The surface of Earth is not flat in that context. If you make a triangle on a perfectly flat area, the interior angles add to exactly 180 degrees. If you make a triangle on the surface of Earth, you'll see that the angles add to more than 180 degrees: The surface of Earth is curved. Within the precision of our current measurements, the universe is flat: If you make a triangle, the angles will add up to 180 degrees. Holographic universe: It is the idea that the world might have one dimension less than we think it has, similar to a hologram on a 2-dimensional paper that looks 3-dimensional if you see it (hence the name). We don't know if that is true. A recent study found that both a normal 3-dimensional world and a 2-dimensional world are in agreement with observations, with the 3-dimensional world leading to a slightly better (!) agreement. We don't know yet, and we will need more precise measurements to see what works and what does not. All this is independent of string theory, which is an interesting approach, but cannot make good predictions yet."], "text_urls": [[]], "score": [3]}}, {"q_id": "5rf0v2", "category": "Repost", "title": "What's the benefit of displaying a menu price without tax included? Plenty of countries include the tax in the final price but the U.S adds it separately.", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dd6p8vb", "dd6p6kw", "dd6r2jt", "dd6ppa9"], "text": ["If your competition doesn't show the price tax-included, it makes their products seem less expensive (even if they're the exact same price or a little higher). In addition, it allows advertising to be done for prices across boundaries where the tax rates might be different (such as across state borders - or sometimes even within a given state). It also means any changes to the taxes in an area doesn't mean you suddenly have to reprice everything manually. It also lets you easily see exactly how much tax is being paid by looking at your receipt, instead of just assuming that the company is paying the sales taxes properly.", "Gets people to spend more. Same reason why most prices are not rounded. $4.99 14,995 Strangely enough studies have shown that menu prices in restaurants that just show a whole dollar figure make the diner feel like the restaurant is more luxurious. I.e. 12- vs $11.95.", "Just taking McDonlads as an example. There are over 14,000 restaurants in the nation. Printing menu signs for each and every one is going to cost a significant amount of time and money. Standardizing the signs across the board allows them to save a lot of money and give a consistent experience. Taxes and laws are different everywhere in the USA, even just across the street. It is to the benefit if the companies to not have to include sales tax so they do not have to individualize each menu. Taxes also change, remember NYs soda tax? Should every restaurant be forced to alter their menu while the law is tested in courts? It would be nice to know the exact dollar amount you are going to pay but if you live in the USA no matter where it is your responsibility to know the local taxes. As an alternative, consider shopping more local as many local places at least around me just do flat fees for food and such, they just worked out the price and tax to equal an even number or close to it.", "Tax can vary by region, and occasionally day. For countries like that, it's easier to put the initial price."], "text_urls": [[], [], [], []], "score": [73, 21, 8, 7]}}, {"q_id": "5rfbc3", "category": "Repost", "title": "Why do our arms move back and forth as we walk?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dd6r4re", "dd6rb4i"], "text": ["You lift your right foot up off the ground and move it forward. You have now shifted the centre of gravity slightly forwards and to the right. If you did nothing to counter this shift in the centre of gravity then you would stumble forwards and walking would be very ungainly. But what you do is swing you left arm backwards (as well as doing other things like contracting certain muscles in your back and other leg) in order to shift the centre of gravity back to the middle and keep your balance.", "It's something your body has subconsciously developed to help you maintain your sense of balance. If you will watch a child learning to walk they do not do it as much and fall a lot. Once then understand how to walk they also develop the arm swing."], "text_urls": [[], []], "score": [5, 3]}}, {"q_id": "5rfioh", "category": "Repost", "title": "What is fair tax and flat tax?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dd6srv1", "dd6usys"], "text": ["A flat tax is one of two things. 1) You charge the same exact tax to every person. So if the tax is $2000 you charge everyone $2000. 2) You charge everyone the same percentage. So everyone is taxed at say 30%. The issue with a flat tax is that it hurts the poor more than it hurts the rich, as there are no exemptions or deductions. Everyone owe a flat percentage of their income, and due to the costs of the government that percentage has to be set high in order to get the money it needs to function. A fair tax does not means anything specific, but I think you are asking about a progressive tax. In a progressive tax you take into account how much harm a tax will do to someone. So the poorest will pay no taxes, and you gradually increase the amount paid in tiers going up 5% or so per tier. This is more \"fair\" because it does less harm. $2000 means a lot when it is 1 months pay or more, but it does not really mean much of anything if it is 1% of your salary.", "The term fair tax is subjective, depending on what is viewed as \"fair\", but I can tell you what a flat tax is. It is generally regarded as a system of income tax where everybody, regardless of income level or possible deductions under current tax law, pays the same percentage of their income as tax. It doesn't matter if you make 20,000 or 2 million, you both would pay whatever it is, be it 10%, 20%, etc. Under most versions of the flat tax, there are no deductions, reinforcing the idea of it being flat and unchanging. Currently in the US, and Europe, and most of the world, taxes operate using brackets, where different levels of income are taxed at different rates. Keep in mind, income is only taxed at the bracket it lies in. If I make 100,000, at the first 10,000 is tax exempt, I pay no income on that. However, income between 80,000 and 100,000 might be taxed at 25%. There are arguments for and against a flat tax, and whether it is fair. One argument for it is that since everybody pays the same percentage, and the same amount relative to income, its the most fair way of handling it. The argument against it is that affluent people have the ability to pay higher taxes without hurting themselves financially as much as the same tax would hurt a poorer person."], "text_urls": [[], []], "score": [7, 3]}}, {"q_id": "5rkz3q", "category": "Repost", "title": "How did the first bilingual person learn a second language?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dd83ewz"], "text": ["This is basically how two people who have different languages learn to speak to each other (think two people on an otherwise deserted island). So, you start with basics. Point at yourself and say your name. Point at a coconut and say \"coconut\". Point at a fish and say \"fish\". The other person does the same in their language. You go from there and get more complex as you go. Fish becomes \"trout\" or \"bass\" and so on. Make a face when you taste something awful and say \"bad\". Now you are on adjectives. Keep going and eventually you will be chatting away."], "text_urls": [[]], "score": [3]}}, {"q_id": "5rl1dp", "category": "Repost", "title": "The Doomsday Clock", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dd84h8k"], "text": ["The Doomsday Clock is a symbolic clock used to represent how close we are to total nuclear war, which happens at midnight. It's promoted/managed by a committee of nuclear scientists in cooperation with other people. Every now and then they look at the current political climate, and international tensions between countries with nuclear weapons, and make a formal statement about the dangers of the current situation to continued human existence. They are concerned scientists worried that politicians, and most people, are not completely aware of the dangers and implications of global conflicts in an age where nuclear weapons exist. They do this by ceremonially adjusting the clock hands closer or further away from midnight, depending on how close they think we are from war. In short, it's a fancy ceremonial political statement by scientists using a symbolic clock, a criticism of how people do not take nuclear threat seriously enough."], "text_urls": [[]], "score": [3]}}, {"q_id": "5rlzt3", "category": "Repost", "title": "(and not American): What is \"Alt Right\" and why is it a big deal that their sub was banned?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dd8b5mk", "dd8b7oh"], "text": ["Alt right is a term used to describe a group of mostly young white males who feel that they have become disillusioned and lost in the shuffle. With things such as affirmative action, there has been a big push for women, minorities, and members of the LBGT community to have more representation in jobs and culture (certainly not limited to starring roles in movies and TV). Because of this push, these young white men feel that there's no place for them, that because they're not minorities or women, that their opportunities are diminishing. It's a big deal because they support racist, sexiest, and xenophobic ideals. They see those women and minorities as a threat to their livelihood. I mean, imagine having the feeling that you don't belong in society? You're going to find someone to blame. (This is the anecdotal part, please don't delete this comment) Personally, as a young-ish white male, I don't agree with the alt right movement but I completely understand where they're coming from. I will fully admit that there has been more of a push for inclusion, but the fact is that most of the jobs are still given to white males.", "Internet neo-nazi's, white nationalists and white supremacists decided to rebrand themselves. If you listen to self-described alt-right people talk, they talk about how the white race is under attack, wanting a white homeland, and the 14 words (the big neo-nazi slogan). They give \"statistics\" on the IQ of different races. Neo-nazi's decided to rebrand themselves, and we let them. Some people are mad that reddit banned the group for doxing (revealing private/confidential information), calling it censorship and an attack on free speech. But reddit isn't the government, so it's not an attack on free speech. And it has the right to ban people for violating their ToS. Also, no one should have to host content on their site that they don't want."], "text_urls": [[], []], "score": [29, 12]}}, {"q_id": "5rn990", "category": "Repost", "title": "What is gaslighting and what are ways to tell if it's happening?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dd8k4ok", "dd8jqy2", "dd8jr2k", "dd8madf", "dd8lgsn", "dd8lidw", "dd8lai1"], "text": ["Gaslighting is a form of psychological abuse where the abuser attempts to convince the abused that they are crazy. It is named after an old movie called *The Gaslight* where a wealthy heiress is seduced by a man who wants her fortune; one of the key parts of the movie is that she believes their gas lights are flickering, but he says that's not possible to hide the fact that while searching for her fortune he is disrupting the gas flow to the lights. The main sign of gaslighting is someone denying and lying about things you know to be true. Such as lying about things you've done or things that you've both experienced. Lying about other abuse is a common form of this in schoolyards (e.g. I didn't push you, you fell and I tried to catch you). This kind of abuse can also include other typical signs of psychological abuse like cutting you off from other people (causing you to become dependent upon your abuser), and making you feel stupid or unskilled.", "Gaslighting: to manipulate (someone) by psychological means into questioning their own sanity. There is a list here of actions to be able to identify: They tell blatant lies. They deny they ever said something, even though you have proof. They use what is near and dear to you as ammunition. They wear you down over time. Their actions do not match their words. They throw in positive reinforcement to confuse you They know confusion weakens people. They project. They try to align people against you. They tell you or others that you are crazy. They tell you everyone else is a liar. [Source]( URL_0 )", "If you feel normal away from someone, but insane when they have influence, that's a sign the person is intentionally, or unintentionally \"gaslighting\" you. Being unknowingly involved with unbalanced people makes us question our own sanity.", "As others have said it's repeatedly lying to a victim until they question their own sanity. What I wanted to point out though is a famous (albeit fictional) example many people may not have realized. There is a famous Star Trek: The Next Generation episode (\"Chain of Command\") where Picard is captured and tortured. He is repeatedly asked how many lights his captor is shining. There are 4 lights, and he repeatedly tells this to his captor. But the captor always tells him he is mistaken. This is gas lighting. His captor is attempting to break Picard by getting him to admit there is a different number of lights than are actually present.", "There was a gas lighting ELI5 a couple months ago and it had some really good explanations in it! I would search for it if you can, there were really good examples.", "Ah, gaslighting. That's when someone is trying to make you think you're crazy by asserting that something they know to have happened did not in fact happen or vice versa. This is the worst thing you can do to a person with a mental illness. People with bipolar disorder, to use a disorder I'm familiar with, have bouts of paranoia. This can be triggered by psychotic episodes or major depressive episodes. They rely on those closest to them to \"sanity check...\" i.e. \"Am I perceiving these events correctly or am I misinterpreting what happened.\" If that person abuses that trust (\"this is all in your head!\") to win an argument, now there's less trust and instead of sanity checking the mentally ill person will just go with what they're perceiving.", "Is the term gaslighting applicable if the offender is unaware they're doing it, i.e. They are suffering from BPD or some degree of NPD that results in them having revisionist memories?"], "text_urls": [[], ["https://www.psychologytoday.com/blog/here-there-and-everywhere/201701/gaslighting-know-it-and-identify-it-protect-yourself"], [], [], [], [], []], "score": [160, 45, 17, 10, 4, 4, 3]}}, {"q_id": "5rq8z6", "category": "Repost", "title": "How can they know what a black-white picture looks like in color?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dd99r0e"], "text": ["They just guess what colors should be there. For example we know what color the grass, sky, or skin color would be. Things such as a shirt, wall paper, or a book would just be our best judgement."], "text_urls": [[]], "score": [3]}}, {"q_id": "5rqp3d", "category": "Repost", "title": "[Video Inside] Brick layers using domino effect which then shoots backward at 2x speed seemingly against physics to lay the bricks perfectly.", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dd9dku8"], "text": ["It's not at all against physics. Here's a [video]( URL_0 ) that explains it with words *and* pictures, but since I don't wan't the mods mad at me for not explaining shit in ELI5, here's the explanation: When a brick falls, it pushes into the next brick, which pushes into the next, and so on. As brick A falls, it gets caught on the edge of brick B, which is caught on the edge of brick C, and so on. When brick Z falls, it doesn't hit something, so it can fall all the way. That frees brick Y to fall the rest of the way, which frees brick X, and so on, until brick A falls. Since the second round of falling doesn't need the bricks to fall as far to trigger the next drop, the return happens even faster."], "text_urls": [["https://www.youtube.com/watch?v=coqbMpJtHcg"]], "score": [8]}}, {"q_id": "5rt68m", "category": "Repost", "title": "If a hummingbird is flying inside of a car and the car is moving but the hummingbird is simply hovering will it hit the rear window because it is not flying forward? When the car stops would the hummingbird hit the front windshield?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dd9xabh", "dd9xp9n", "dd9x96e"], "text": ["It's as if you were standing in the train. At a constant speed you don't really feel anything, but when accelerating or decelerating you will feel the effects. So at constant speed the hummingbird can just hover, but when accelerating it will be drawn to the back and when braking it will be drawn to the front.", "I wonder if a hummingbird would behave the same was as a helium balloon. The behaviour is a little counter intuitive. When you accellerate, the balloon moves FORWARDS in the car. and when you brake, it moves backwards. Why? Air pressure. When you accellerate, the air gently moves towards the back of the car. There is more pressure in the back, thus pushing very light floating things forwards. Vice versa for braking. Here's a video discussing it: URL_0", "Thee hummingbird flys because it is pushing the air with its wings. All the air in the car is moving forward at the same speed as the car. Think of it the same way you would a fish swimming in a fish tank in the back of your truck."], "text_urls": [[], ["https://www.youtube.com/watch?v=y8mzDvpKzfY"], []], "score": [10, 5, 3]}}, {"q_id": "5ryp1m", "category": "Repost", "title": "Why is polygamy illegal?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddb7391"], "text": ["Because to the state, marriage is not about romance or fidelity; it is about a legal partnership. So they have regulated it to be uniform."], "text_urls": [[]], "score": [7]}}, {"q_id": "5rzb5g", "category": "Repost", "title": "The Dodd Frank act.", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddbciud"], "text": ["With the disclaimer that Dodd Frank is an incredibly complex law and it's hard to know all the details, here are some of the hightlights: * 1. instituted higher capital requirements for \"too big to fail\", including so called shadow banks like GE's finance arm * created the Volcker rule to limit proprietary trading(basically, you can't use peoples deposits to bet on stuff for your own bank), which can be risky * created a wind down procedure for big banks, so in the case of a crisis they won't threaten the rest of the URL_0 's a \"living will\". Basically, they have to simulate how what they would do if the economy tanked again, so they don't blow up and take everyone else with em. the of the above are audited/enforced by the Fed to insure compliance * created the CFPB- the SEC's sister orgnanization(the SEC only protects investors, not consumers), whose goal is to protect consumers (they were behind the big Wells Fargo fake account bust), mainly by consolidating regulations that were already on the books in various agencies, but not a priority * required derivatives to be traded through a clearing house to improve transparency (ie, to enforce standards so people know what they're getting into tldr: Tries to make banking safer by reducing the amount of risk that banks can take on, in order to avoid another 2008. edit: Sorry about formatting, lists are a pain in the butt."], "text_urls": [["economy.It"]], "score": [4]}}, {"q_id": "5rzeh7", "category": "Repost", "title": "Why do we feel the urge to destroy things when we're angry?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddbdmwc", "ddbdi8b"], "text": ["I'm sure someone can answer this better, but I can at least partially try, since I teach this to 5 year olds as part of a self-regulation program in my classroom! So, there's a part of your brain called the amygdala, which has to do with emotions. Basically, when you get angry, your brain perceives there is some sort of threat to you, and your amygdala triggers the impulsive fight or flight response. Things such as hitting someone or throwing something/destroying something when we're angry are examples of this. There's another part of your brain called the pre-frontal cortex that we call the 'wise leader'. This part is where reasoning happens, where you, for example, assess the situation that you're in and choose a course of action (such as using words when angry, instead of hitting/throwing). We teach this to young children because in order to think reasonably in the face of emotions such as fear/anger, you need to be able to 'calm the amygdala' so that your pre-frontal cortex can think things through before you react. Some people are better at this than others (young children, for example, but this skill in adults also varies greatly), but it's also something that can be taught and learned. 'Exercising the brain', if you will!", "Probably has something to do with the evolutionary roots of anger, and it triggering a response that would have been advantageous. I imagine anger is useful to override sensible feelings of fear where one would rationally select the flight over fight response. Threats to offspring would probably be the instance where this is evolutionarily wise - get angry and punch that lion in the face, it might decide your bebe isn't worth it, or it turns to you and your troupe of kids get away to sew your genes further down the road. Upto a point, defending resources, and safeguarding the life points they give you is another probable."], "text_urls": [[], []], "score": [10, 6]}}, {"q_id": "5s04ti", "category": "Repost", "title": "What is happening when you're falling asleep and suddenly feel like you're falling?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddbhko3", "ddbk0p0", "ddbjp4d", "ddbk4ki", "ddbkk3l", "ddbj728"], "text": ["It's called a hypnic jerk, and I only know of a theory, as it is poorly understood. So, you're lying down, feeling sleepy, you've had a rough day, your body tries to rush you into sleeping, instead of going through all sleep phases, it skips them and goes directly to REM sleep (rapid eye movement - this is when you usually start dreaming). When your brain does that, it didn't give your systems enough time to cool off, so instead of a gradual lowering of temperature(T) , heart beat(HR) and respiration rate(RR) , there's a sudden low T, HR, & RR, your brain then thinks yours systems are failing, and sends a signal, a twitch throughout your body to jump start them again. Again, this is one of the suggested theories as it's still a poorly understood phenomenon.", "Many years ago I read a book, I think it was Dragons of Eden by Carl Sagan. In the book was the theory that it was a reaction based on our evolution from apes. We used to sleep in trees and if we were to slip while asleep our bodies would jerk us awake to prevent our fall. I could be wrong. I often am.", "During Stage 1 NREM, the body is trying to transition from awake states to deep sleep. During that period, the body starts to block some sensations and slow down bodily processes. The reason you feel like you are falling is because your body has desensitized the sensation of pressure from the bed, so you panic and reach out to grab something, which brings you back awake to realize you were just in your bed.", "Its called hypnagogic jerk. It is believed to be a minor epileptic event. Vsauce talks about it in his video about Dejavu. Worth watching. URL_0", "scientists of reddit. I experience 'falling down' almost each time when i sleep after drinking. If you sponsor me drinking, i can volunteer in your research.", "When you sleep all your muscles will relax. This causes the part of your brain that balances you to detect that you're falling as it thinks you're still standing up and if your muscles are relaxed then you would be falling so it does a massive jerk to stop you."], "text_urls": [[], [], [], ["https://youtu.be/CSf8i8bHIns"], [], []], "score": [514, 89, 27, 20, 18, 9]}}, {"q_id": "5s0vni", "category": "Repost", "title": "Why do we use the base 10 system, and what are its benefits over other mathematical systems?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddblh1q", "ddbphmd", "ddbm56r"], "text": ["no benefit, other than a convenient correlation with the number of fingers. there are better systems that work better with the base 2 of computers and which have more easily divisable fractions. Base 16 would probably be an ideal candidate for both things.", "tl;dr: The decimal (base 10) system came to be bacause humans have 10 fingers and it made sense. There are other systems that are better, but we're stuck with this one because people don't like change. It was used by the ancient Egyptians and Greeks (Romans had a decimal number system, but they did it differently, and nowadays it's used in a more decorative context) and our modern 10 written numbers come from Arabic numbers. There are plenty tribes in the world that use different number systems, like base 12, 32 and 27. It's understandable that these don't make much sense to us, but it's important to note that mathematics doesn't care about which number system is used - the basic principles still apply. Curiously, the people who use base-27 actually point to their body to indicate numbers as we would by extending fingers. As for advantages of the decimal system, well, multiples of 2, 5 and 10 are easier to calculate in your head than, say, multiples of 7. That being said, many systems are superior in terms of factors, like aforementioned base-12 which can be divided nicely into twos, threes, fours and sixes, or the base-60 system which was used by the Babylonians, which has 12 factors! If you'd like to know more, [here's a nice video from Numberphile]( URL_0 ) - it's about base-12, but he talks about the decimal system too, as well as some interesting tidbits that I haven't mentioned, like the role the French Revolution had in most measuring units being decimal.", "It's arbitrary. I think 12 would be great (so many divsors) or better, hexadecimal. I'm assuming that alien civilisations we encounter will use hex. They aren't stupid."], "text_urls": [[], ["https://www.youtube.com/watch?v=U6xJfP7-HCc"], []], "score": [13, 5, 3]}}, {"q_id": "5s142p", "category": "Repost", "title": "How can fishes survive tremendous pressure in sea/oceans with soft skin?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddbmwzi", "ddbqab7"], "text": ["It's not pressure that kills us, it's pressure differences. We can't survive down there because we're filled with air, and the pressure difference is so great that we'd be crushed. Fish, however, are filled with the same water that they're swimming in, so at best the pressure difference is minimal", "Jammin-Johns answer is about the size of it. There are also microscopic differences in their biochemical structure but his answer is essentially right. Copying and pasting from my answer about \"Why are Sea Creatures to Big? Shouldn't Pressure make them small?\" Considered modifying it slightly to address the difference in your question but think it's just additional helpful information, so leaving it. The major issue has to do with differences in pressure. If you took a submarine and sent it to the ocean floor, it would get crushed. But if you cut a hole in the submarine and let it sink to the bottom, it would not, because the water inside would be at the same pressure outside and they would cancel eachother out. Humans have a problem because we have all sorts of air in our bodies. There is air in your lungs. In your digestive system. There is air in the sinuses of your skull. If you tried holding your breath and diving to the ocean floor, your rib cage and skull would crush long before you got there. There are other structural, metabolic and physiologic problems for humans to survive at depths but I don't think you were asking about those. Deep sea fish don't have so much air in their bodies, so, for example, they won't have swim bladders life surface fish do. They also have a very high water content of their cells. Water is notoriously incompressible. Putting more pressure on it will simply make it push back with the same pressure---its volume won't change, unlike a balloon filled with any gas. Deep sea creatures also have differences in terms of the structure of their organs and even the enzymes in their cells so that they can withstand higher pressures while maintaining their shape and function. You don't have this, so you would get squished even if air wasn't a big problem. What about whales? Whales are actually mammals and breathe air. They have lungs. But unlike you, their rib cage is very flexible and their lungs are specifically adapted to getting crushed when they dive. Pressure itself then is not a very limiting when it comes to size. In fact, the ocean environment (though not pressure) might even facilitate it. Because of buoyancy, they feel less stress from gravity enabling them to reach larger sizes. Large size also means they have less surface area to lose their body heat, so they can survive with slower metabolism, even in colder temperatures. There aren't so many things that can go into the deep sea, so they might be less likely to suffer from predation. I made that last one up, though. We don't really know why/how some creatures got to be so big, but pressure is not a limiting factor, at least not for the pressures you encounter in the deep sea."], "text_urls": [[], []], "score": [28, 18]}}, {"q_id": "5s18el", "category": "Repost", "title": "Why is it that, on electric fans and other appliances, the order of the settings is OFF, HI, MED, LO?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddboxem", "ddbr7la"], "text": ["The motors need a lot of power to start from a stop position. Low power sometimes isn't enough power so the best choice is putting it on high as the first step.", "Electrician in the works here It's bad practice to demand more electricity as the knobs turn. So it starts off at the highest to demand the electricity it needs to start and then lessens the load as you go on. High med low All fans are designed this way for safety"], "text_urls": [[], []], "score": [30, 10]}}, {"q_id": "5s1a4y", "category": "Repost", "title": "how do cows gain so much weight eating only grass?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddbrm9u"], "text": ["In a day, a cow spends about 6.5 hours eating and drinking all of her food. The cow has four stomachs and undergoes a special digestive process to break down the tough and coarse food it eats. When the cow first eats, it chews the food just enough to swallow it. The unchewed food travels to the first two stomachs, the rumen and the reticulum, where it is stored until later. When the cow is full from this eating process, she rests. Later, the cow coughs up bits of the unchewed food called cud and chews it completely this time before swallowing it again. The cud then goes to the third and fourth stomachs, the omasum and abomasum, where it is fully digested. Some of this digested food enters the bloodstream and travels to a bag called the udder, where it is made into milk that will come out of her teats, while the rest goes towards the cow's nourishment."], "text_urls": [[]], "score": [3]}}, {"q_id": "5s5r9e", "category": "Repost", "title": "Why do places like India and China have such a higher population than the rest of the world?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddcmxrh", "ddcl9f8", "ddclpm3", "ddcq9d5", "ddcmckr"], "text": ["Rice, rice, baby. Of all the crops available to the preindustrial world, rice produces the most calories per acre. At the same time, rice is more labor intensive than most crops. That means rice can both support more people per acre, and *requires* more people per acre to farm it. If you have a lot of land suitable for rice, you are going to have a great population density than your barley growing neighbors.", "I'm from India, and I think the one of the major issues is the culture here. It was kind off the norm to have multiple kids. At that hasn't changed since. Lack of education is also one of the major reasons. The poorer sections of the society are ignorant of contraceptions or are indifferent. Even if their income is barely sufficient to sustain them, they continue to have sex and make children, because that's all that they know. And since almost 70% of the population of India are in the poorer side of the spectrum, the ramifications of this is large. Hence the population continues to blow up since a family will atleast have 2 or 3 children.", "They have had a larger population for a very long time. Agriculture developed in their river valleys. Farming there developed a population density which persists. You can watch youtube videos on this. They still are very productive.", "They don't. India and China have about the same square km size as Europe, however, Europe has a lot more mountainous regions and areas of low/little farming/habitation compared to those regions if you account for everything. Europe has a population of ~900 million with China and India having 1.3 and 1.2 Billion respectively. N. and S. America are just less populated because they have only experienced the agricultural revolution for about 500 years, give or take, on a large scale so their collective population is 1 Billion.", "There may be an element of having lots of children so that you will be fed and cared for in your later years. It is also a cultural thing."], "text_urls": [[], [], [], [], []], "score": [18, 10, 4, 4, 3]}}, {"q_id": "5s6gtt", "category": "Repost", "title": "How/why does a circular camera lens create a rectangular picture?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddcr4pl"], "text": ["A circular lens projects a circular image, as you'd expect. That image, however, is projected onto a rectangular piece of film or a rectangular electronic sensor and the far edges of the image get cut off. This is good because the stuff at the edge tends to be blurry, dim, distorted and out of focus."], "text_urls": [[]], "score": [5]}}, {"q_id": "5s80hp", "category": "Repost", "title": "why do people's accents seem to disappear when they sing?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddd4l9a", "ddd4dlg"], "text": ["BA in linguistics here. I believe it is for a couple reasons. Reason number one being that you simply don't hear it as much. The differentiators in accents (particularly American accents) are in things like \"r\" sounds and vowel sounds, and when you hold these sounds out in a long way like you're singing, they sort of morph into a more universal pronunciation- if you're Scottish and roll your R sounds, or American and pronounce your R sounds very hard, or from London or Boston and ignore them completely (like \"cah\" instead of \"car\") it all sort of comes out the same when you hold it out to fit the cadence of a song. Second major reason has to do with the style of music. I think pop music and rock music are generally associated with a specific style, same way country music is. Look at Keith Urban, he is an Australian country singer and he still sounds like all the other county singers from the US. EDIT: spellings and stuff", "One of the hallmarks of good singing is to produce big rich vowels. Making the resonant cavity of your mouth and throat as big and open as possible helps with this. Certain accents rely on having a more closed vowel sound, so singers (in English at least) often drift towards a more generic accent because the focus is on achieving a better tone. That being said, a common criticism of singers is that they sing with a fake accent. Americans that sound British, Brits that sound American, etc. Here on the west coast I've met a lot of singers who unintentionally put on a southern accent."], "text_urls": [[], []], "score": [5, 3]}}, {"q_id": "5saoe2", "category": "Repost", "title": "What makes a person left handed and why? How is it possible considering most people are right handed?", "title_urls": {"url": []}, "selftext": "I hate to sound like an ass, but this is something i recently thought of when watching my brother draw. He's one of three or four lefties on our moms side and it's just something that caught my interest recently. What exactly makes a person left handed and why? Also I didn't want the title box to be super long, but I also wanted to know if there were any cultures or civilizations that are predominantly left handed.", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dddscx8", "dddl142", "dde1t5d"], "text": ["It's a genetic thing. [Some current theories]( URL_1 ) about handedness are that it takes several different genes in a particular alignment to make someone display a left hand dominance. This is why only about 10% of the population is left hand dominate. However, only a small percentage of that 10% is truly left hand dominate. Most are really [Cross Dominate]( URL_2 ) meaning that they use either hand to accomplish various tasks. Not that they can use either hand to accomplish the same task, but for various tasks, they have a dominate hand. Me for example, I write and hold eating utensils always with my left hand. But I hold drinking containers in my right hand. I'm also completely right handed in baseball and hockey, which is slightly weird because right handedness in hockey is the minority. > but I also wanted to know if there were any cultures or civilizations that are predominantly left handed. Probably not as being left handed is (still to this day) [frowned upon by some cultures]( URL_0 ) as being \"evil\".", "[This]( URL_0 ) very informative video answers most of your questions. Hope it helps.", "The fact that I'm left-handed has nothing at all to do with genetics. When I was a baby, my step-dad(who's a leftie) wanted me to also be a leftie. Whenever I had become old enough to start to reach for things, I would do so with my right hand. He would actually gently push my hand away over and over until I reached for whatever it was with my left hand. After so many times of him doing that, I must've learned that I would get what I wanted whenever I reached for things with my left hand. I love being left-handed, but I let my daughter choose for herself lol. She's a rightie :)"], "text_urls": [["https://en.wikipedia.org/wiki/Bias_against_left-handed_people", "http://onlinelibrary.wiley.com/doi/10.1111/nyas.12102/abstract;jsessionid=CEB71D536F35708B3A4779EA4A6E8D06.f02t04", "https://en.wikipedia.org/wiki/Cross-dominance"], ["https://youtu.be/TGLYcYCm2FM"], []], "score": [17, 6, 3]}}, {"q_id": "5sc6bo", "category": "Repost", "title": "The act of cutting a piece of paper or any other material. How does it work on the microscopic/atomic level?", "title_urls": {"url": []}, "selftext": "When cutting any material how exactly does it separate on the tiniest of levels. What causes the separation? Why are some materials sharper than others?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dde1dbu", "dde0w83", "dde2w0r", "dde012i", "dde9235", "dde74pd", "dde9m7z", "dde3ulk", "ddebuic"], "text": ["That's a lot of questions. Let's do them one by one. Edit: Yes. I know it's \"intermolecular\" not \"intramolecular\" I messed it up and you're right if you corrected me. **How does cutting something work?** Individual molecules are connected by bonds called ~~*intramolecular*~~ *intermolecular bonds*. These come in a wide variety of types, some more permanent than others. In the case of something like a metal (or any single element bonded to itself many times over) this means there shared electrons forming a permanent bond between any two atoms of the material. In the case of more complex molecules, this means there are weaker bonds holding the material together, either through polymerization, hydrogen bonding, dipole-dipole interactions, or London Forces (although the last three happen most often in liquids and are fairly temporary bonds comparatively). Paper is a polymer. You can see the general structure of the main component, cellulose, [here]( URL_1 ). The structures shown in brackets in the previous diagram repeat throughout the material, and connect to a structure of the same type at the ends that cross the brackets. If you expand the idea of what a polymer is to be anything with a repeating unit, then most things can fall into that category (metals are a repeat of the metal atom unit; glass is the repeat of the Silicon Oxide unit). You might notice on the cellulose that it only had connections at either end of the molecule (where it crossed the brackets); other materials can have many more connections between their repeating units (for example, glass can form more [3-dimensional structures]( URL_3 ) that loop back onto themselves, and iron forms a fairly regular [metallic structure]( URL_2 )). However, when the material is forming, different *grains* can form. In polymers like paper and plastics, this means that there are distinct layers and \"strings\" of polymer can form. In materials like metals or glass this means that several different areas will crystallize independently forming areas that are uniform but which run into areas that are different yet uniform with themselves (you can see the idea of \"grains\" [here]( URL_4 ) where each area that's shaded uniformly is uniform with itself, but not necessarily oriented the same as the areas directly next to it). **What causes the separation?** Either way, when you cut a material, you're exploiting the fact that there are imperfections in it. In the case of paper this means that you're cutting \"between strings\" of polymer and occasionally breaking a bond between two pieces of a single polymer string. Picture a big plate of spaghetti, if you push a knife down the middle of the plate, some of the noodles are going to move out of the way and some of them are going to get cut. That's what's going on when you cut paper, except imagine that your paper is about 400,000 noodles wide. Metals will tend to break along grain boundaries. It's possible to break it where you want instead of the grain boundary, but if you were to just chisel at a metal you'd tend to break along the grain boundaries. When you cut it with a more precise tool (such as a saw) you're relying on the fact that the connections holding any single atom that you're not directly influencing are stronger than the connections holding onto the atoms you are directly influencing. If you extend the Iron structure I linked to earlier further out and imagine you're cutting a swath out of the middle of it, it's easy to see how there are more connections holding the rest of the atoms together than are holding the atoms you're cutting away. **Why are some materials sharper than others?** The issue here isn't *sharpness* so much as *hardness*. Hardness isn't particularly well-defined scientifically, although we know it depends on bond strength and geometry. Bond Strength: This is the cumulative force holding together the material. It includes all the ~~intramolecular~~ intermolecular forces we discussed earlier. Iron is stronger than paper in part because iron bonds many more times to itself than paper bonds to itself. The energy it takes to remove a single iron atom is much larger than the energy it takes to remove a single cellulose repeating unit because the iron is better held in place. Bond strength also involves the chemistry of the molecules that are bonding. Geometry: Triangles are strong. That's why we use them in [bridges]( URL_0 ) so often. A force on any point distributes the force to the two adjacent sides. Thus, if a grain boundary ends in an edge similar to a triangle, it's going to be able to withstand much more force than a grain boundary that doesn't. It's very hard to get a paper polymer boundary that is triangle-shaped, but it's pretty easy to get an iron boundary that is. If material A has better bond strength and geometry than material B, then material A is harder and will cut through material B. How much harder A is than B determines how many times you can cut through B before your chunk of A is useless as a cutting tool. (When your A and B come together, A does cut B, but B does some damage to A as well, this is why knives dull with use).", "Just for an easier example, if i have a bunch of magnets stuck together, each magnet being an atom, and i separate the magnets, the magnets dont get cut in half. The bond between the magnet simply is removed. That is essentially what happens with cutting a material. Edit: Wow guys, thanks for the upvotes! As for people questioning about why paper therefore doesn't bond back together, that is because many other particles get in between the paper pieces, preventing them from completely bonding back together. There are ways to bond materials back together, but those involve energy being used, and vary depending on material. Also, definitely check out the other results that explain much more in depth how this works, this is just a quick analogy for those who want a simple example.", "I always wonder two things about cutting stuff... 1) I understand that when I cut things, I am simply breaking the bonds between the molecules. Why then, can't I hold those pieces back together and have them refuse at some point. Is the gap I created simply too far? 2) Why don't I ever accidentally, given the number of things I cut over my lifetime, ever cut an atom in half and blow up my town?", "Nothing is happening at the molecular or atomic level. The paper is held together by intermolecular (electrostatic) forces. Pretty much every bulk piece of matter, other than metal or crystal, is held together this way. When you cut with the scissors, you are pulling apart weak bonds between molecules.", "Top answer is not for 5yo and most of the stuff here is wrong. My attempt: Paper (and other materials) are made of small chains called molecules. They are bound very closely together with electrical forces. These forces can give up and those molecules separate from each other when you apply some force like with a scissors. You cannot simply \"glue\" the pieces together by touching sides because you need them to be incredibly close together so the electrical force is strong enough to hold them together again. You you could, it would work. And, when you rip paper apart, you're separating these molecules the same way. The only thing scissors do, is help you apply a stronger force along an exact line.", "You know how you when you move you cut through air? Your molecular structure is more dense therefore you moving through other molecules separates them because they have less space inbetween. Everything works kinda like that. Bonds are forces that hold molecules together and there are several types of bonds. Gas molecules are kinda loosely floating about, rather light in weight, and aren't super attracted to each other so they're very easy to seperate and just kind of move aside. Liquid molecules are heavier and like to hug together but not enough to hold a shape so they have enough space in between and few enough bonds to still fairly easy to seperate so they move aside but want to connect. Solid molecules have lots of connections holding them all together like threads hold a shirt together. They're the heaviest molecules and they are able to push other molecules out of the way. Mass/weight is one of the main factors in being able to move things, the other being energy. If the molecules are extremely densely packed in a very tightly arranged formation with strong bonds holding them together, then they're going to be hard to separate. The tighter the bonds and structure and less space inbetween, the sharper it can be. Some materials are typically strongly bonded, very dense and heavy, and able to hold together in very thin strands of molecules. These are sharp. Other materials aren't as heavy or bonded as strongly, so they can't be as thinly strung or they'll just fall apart. There are many exceptions depending on the elements making up the molecules of course, and different atoms or forces shared between them can make them interact differently.", "Question: if you do cut paper, why does not lead to the edges breaking the chain and lead to a new compound along the edges?", "The simplest explanation I can come up with is that your cutting tool comes in between intermolecular forces holding the material intact. In your example, your scissors force an edge in between hydrogen bonds, causing the bonds move farther apart, which after some distance reduces the probability of their affecting each other to pretty much 0. Some materials are sharper than others because they expose an edge that isn't as wide. Of course, they're more brittle for basically the same reasons (fewer bonds, etc). Disclaimer: Not an expert.", "Basically the pressure that you apply with scissors or knife is stronger than the bonds between molecules, so they just break apart. Imagine squeezing some lego bricks quite hard and how they would split off even though they are stuck together to begin with."], "text_urls": [["https://mathspace-production-media.mathspace.co/media/upload/images/8-Geometrie/8th-geometry-warren-truss-bridge.jpg", "https://upload.wikimedia.org/wikipedia/commons/0/07/Cellulose_Sessel.svg", "http://previews.123rf.com/images/molekuul/molekuul1301/molekuul130100056/17236567-Iron-Fe-ferrite-metal-crystal-structure-Unit-cell--Stock-Photo.jpg", "http://www.pslc.ws/macrog/images/glass01.gif", "https://i.ytimg.com/vi/uG35D_euM-0/maxresdefault.jpg"], [], [], [], [], [], [], [], []], "score": [2960, 2198, 464, 98, 41, 20, 4, 4, 3]}}, {"q_id": "5sf8bv", "category": "Repost", "title": "If our body temperature is 98F, why is room temperature 72F as opposed to 98 or any other temperature?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddekboh", "ddelncf"], "text": ["In a 98F environment, the body would not be able to get rid of excess heat (generated by metabolism) by passive conduction, and sweating becomes the only efficient means of discharging heat. In addition, in most climates, such a temperature would be expensive to maintain as opposed to the 70s", "Disclaimer: values in Celsius because I can't Fahrenheit. The human body produces heat through its activities. The amount of heat generated will vary depending on the individual metabolism and whether we are standing still, running, sleeping etc, but generally speaking the heat generated is more or less constant. Our bodies however have developed mechanisms that allows it to modulate the heat dissipation, which in turn makes us able to live in contact with a wide array of environmental conditions. We can survive relatively well in cold temperatures (around 0\u00b0C) by producing more heat/letting less heat escape (through our body hair for example); on the other hand, sweating allows easier heat dissipation when confronted with warm environments (32\u00b0C +). That being said, room temperature (25\u00b0C) is just a arbitrary point chosen by us, warm-bodied humans, as a temperature in which the amount heat generated by our bodies is more or less equal to the heat dissipated to the enviroment (due to it being slightly colder than our bodies), thus generally being regarded as pleasant."], "text_urls": [[], []], "score": [6, 4]}}, {"q_id": "5sfhtv", "category": "Repost", "title": "How does converting cars and such to electric help the environment?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddemn7w"], "text": ["Non-electric cars run on some form of fossil fuel that is extremely polluting. When you use electricity instead you have more options for producing the energy fueling the cars. So it becomes possible to use less polluting energy sources like solar power, wind power or even nuclear energy. Edited to be more clear"], "text_urls": [[]], "score": [3]}}, {"q_id": "5sg6ry", "category": "Repost", "title": "Why is the measurement of time (seconds, minutes, hours) based around the number 60? Why not a more common base, like 10 or 100?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddes772", "ddez8m2", "ddf64rs", "ddf3pmi", "ddf8xc0", "ddeueaf", "ddf0hbc", "ddf79ja", "ddf2xb8", "ddfcn5i", "ddfa809", "ddf8kgr", "ddfai8h", "ddfao3u", "ddf9yh2", "ddfbbkl", "ddey5c0", "ddf761n"], "text": ["60 is divisible by 2, 3, 4, 5, 6, 10, 12, 15, 20, and 30. Lots of options for splitting time into neat segments. You can divide 60 into halves, thirds, quarters, fifths, sixths, tenths, twelfths, fifteenths, twentieths, and thirtieths. 10 is only divisible by 2 and 5. So you can only divide it neatly into halves and fifths. It's just not as flexible. Edit: I'm a political junkie, so I comment on a lot of threads featuring hot-button issues. But according to my inbox, this is the most incendiary comment I've ever made.", "Everyone answered this well, but note that if you count finger bones (3 on each of 4 fingers) rather than fingertips, you could be counting in base 12 and counting/tracking up to 60 is simple 12 bones and 5 fingertips (which is what we believe the Sumerians did).", "URL_0 \"There are two entirely different kinds of \"minute\" or \"second\", and you have to be careful not to confuse them. In each case, they are 1/60 of some larger unit. When we measure time, we divide each HOUR into 60 equal parts called \"minutes\", and each minute into 60 equal \"seconds\". We also do the same thing when we measure angles, so that each DEGREE is divided into 60 minutes, and each minute OF ANGLE is divided into 60 seconds. The units are different; an hour is not the same as a degree in any sense, and their relationship has nothing to do with the angle corresponding to a minute on a clock, or in the earth's rotation. Here's what happened. The ancient Babylonians liked the number 60, and in fact based their number system on it almost the way we base ours on 10. So any unit would be divided naturally into 60 equal parts. That worked well for various reasons, so early astronomers used that scheme to measure angles, dividing a circle into 360 parts (6 times 60), and then dividing each of those parts into 60 minutes, and then into 60 seconds. The word \"minute\" just meant \"little part\", and \"second\" meant \"second division into little parts\"! At some point people started wanting to divide time into smaller parts too; in ancient times it was hard enough to measure hours, but once mechanical clocks were invented it became possible to divide hours up. How many units should there be in each hour? They might have used 12, as they had long before divided the day and the night each into 12 parts; but someone felt that 60 parts would be nice (probably an astronomer!). So they needed a name for 1/60 of an hour, and since \"minute\" already meant \"1/60 of something\", they called it a minute. They probably never considered the confusion it would cause when someone looked at a clock and asked how far the hand had moved. If I say it moved 30 minutes, do I mean 30/60 of an hour on the dial, or 30/60 of a degree of angle? That's unfortunate; but if you remember that the size of a degree has nothing to do with the length of an hour, and that the two kinds of minutes are just 1/60 of an hour or a degree respectively, then you can see that they just aren't related. If you have any further questions, feel free to write back. - Doctor Peterson, The Math Forum URL_1 Associat\"", "The answers here are interesting, but they just provide arguments why 60 is a good choice, no historical reason as for why 60 was chosen. The previous edition of this question really nailed it. I could go ahead and copy some comments verbatim but it's so young that users there can still receive karma: URL_0", "Lots of people mention the Sumerians, but they definitely didn't have hours, minutes, and seconds to measure time. Rather, the answer lies with the Greeks. In Egypt. Because Egypt was Greek at one point. Specifically, the famous 4th century CE astronomer Ptolemy, whose wildly incorrect views of the universe were the basis of modern science until basically Galileo. In his time, we didn't have decimals. I mean, we didn't even have *digits* yet; those came from India a few centuries later. So we used fractions, and thanks in part to the astronomical traditions inherited from the Babylonians, the common method of approximating numbers was with fractions in base 60. You had some whole number of a quantity, then some number of minute divisions, and some number of *second* divisions, *third* divisions, etc., each of them 1/60 of the previous one. So degrees were divided into minutes (1/60th of a degree), seconds (1/60th of a minute), thirds (1/60th of a second), and so forth, and that's how Ptolemy did his astronomical calculations in the Almagest. Since his book was so influential, it's what people continued to use, in Arabia and then Europe, for centuries until Ptolemy's geocentric view was replaced by actual orbital mechanics around the Sun. Meanwhile, a system of describing time needed to be precise as well for these calculations. They didn't have *clocks*. They had divided the day and the night into 12 hours each, and these were standardized as being all the same length so there'd be 24 equal hours in a day (this was an Egyptian thing too), but there were no clocks so it's not like you could see what time it was. But the numbers were used in the calculations, so they were divided the same way degrees were, into minutes, seconds, thirds, etc. Note that even if you assume geocentricity, the Sun still goes around the Earth on a 24-hour cycle, so you could draw that circle of the Sun going around the Earth and use it as a reference point for the other celestial events being modeled. Well, eventually we got clocks, and since we were already using minutes and seconds as divisions of the hour, those became standard. Thirds were too small to use, so there was no point. That's why today we don't bother with thirds, just minutes and seconds, and we use decimals (because they've been invented) to get smaller bits of time.", "Some good answers already, just wanted to add that they could count to 60 by using the five fingers of one hand to point to the twelve knuckles of the other hand.", "/u/ezbot0 is the only correct person here so far. The ancient Sumerians used base 60 for all numerical values and invented the concept of the second that we use today. All of this stuff about divisibility is total nonsense", "Ten and 100 are common bases now, but we've been measuring time since before base ten was fashionable.", "first of all, we use 360 degrees to make circles and measure the angles of polygons. Next, we use 32 degrees as freezing, add 180 deg. F., and we get the boiling point of water, 212. It's definitely NOT decimal, only. Next, we use 24 hours to a day, 60 minutes to the hour, 60 seconds to the minute, and so forth. Same with degrees latitude and longitude, 1 degree equals 60 minutes, 1' equals 60\", and so forth. also we use 12 to make a dozen as well. It's the same principle, as 24 hours in a day. The reason is Babylonia's hexadecimal system which was base 60, essentially. IN ancient times, they did not have our fractions system. They used integral fractions, which the Egyptians invented and were the basis of fractional maths until about the 1400's AD or so. Each fraction was 1/n, so that everything fractional was expressed as a series of 1/n. 1/2 was easy, but could be expressed using 1/6 plus 1/3. It was a very efficient method of dealing with the details of measurements, the fractions. It was highly efficient as most methods from Khemet. Pen and ink we still use the last 5K years, right? Efficiency. For the Egyptians, PI was 4(8/9 squared). It's about 3.16, and it's the easiest way of expressing PI, as well. using their integral fraction methods. Note how many ways we can cross out 2 3's, 4's, 6 & 8, and so forth. It's a very quick calculation method and finding. But the key was as stated briefly below. 12 is divisible by 1, 2, 3, 4, 6, and 12. Which made divvying up objects a lot easier. Bakers use the dozen even today. This made partial amounts LOTS easier to manipulate. 24 hours in a day?, perfect number, 1, 2, 3, 4, 6, 8, 12, 24. Again, easy to divvy up the days, is not? The numbers of companies in an Egyptian military division column? You guessed it. 12. And multiply by 5, and get 60. So, where using fractions was key, as in measuring, it provided a HUGEly simple, time saving method to do the calculations, right? & highly accurate, too. It WAS Efficient!! Nothing better for 4000 years!!! Least energy all the way. & that's why it was used and succeeded and still does. Least Energy Rules. and THAT's why we still use it. Least Energy, 2nd law of thermodynamics. Processes strongly tend toward least energy paths. Even planets in orbits. Even suns orbiting the galaxy. Even the paths of every single, observable & known, photon. Least energy. Universally true, in the entire universe. Facts? Fusion is seen throughout the observable universe, and the combining of 4 protons to make a very stable He4 atom is least energy favored. 14 gigalight years into the future and up to the present and all spaces in between. & 14 GIGayears into the past, up to the present and ALL times in between. Enormous stability. Also least energy. So, it's NOT just ease of calculating, but thermodynamics and AND physics, too. Least energy Rules. This Is how it works: URL_2 Save energy and the system massively grows, in the long term, as above. This is how it works in the brain/mind: URL_1 And that's the \"Depths within Depths\" understanding underlying the 60's, 24, and 12 counts, too. Physics, universal. And our brain works using least energy, as Dr. Karl Friston (Univ. Coll. London, Dept. Neuroimaging), has repeatedly shown, too, in his work on brain and neuroscience. Dr. M. O'Keefe there got a Nobel Prize in Med./Physiology in 2014, to give some idea of the quality of work there. To whit: a deep and rigorous sets of evidences, URL_0 But you asked..........", "The real question here is why don't we use a base 12 number system? :( then questions like this wouldn't exist", "What's always bothered me is, why make a mile 5280 feet? Why not just a nice crisp, easily mathed number like 5000?", "A little more in-depth than a ELI-5 typical answer because understanding the historical context is key to the reason behind the 'standards' used to measure time. URL_0 TLDR: The ability to measure time increased in precision as advances in technology progressed. Metric system debuted about the time it was possible to measure 'seconds' with reliable precision. First was day/night. It was either dark or it was light. Tracking the movement of the sun/stars made it possible to be somewhat more 'precise' in knowing when it was during day/night in general. Time-keeping devices made it easier to 'sub-divide' the day into smaller increments. Those increments used the 'common' measurements of the day, i.e. base 12, then base 10, and continuing to today's ability to measure to the zeptosecond. A zeptosecond is one trillionth of a billionth of a second. It was used to measure an electron escaping its atom for the first time in 2016.", "I always thought it was based on the average heart beat, about 60 bpm. Could still be partly true, but there's some great other answers here!", "60 hours? I don't think so. 12 hours, as in 12 months (lunar cycles). I would think 12 would be the base, and then come the other (both greater and smaller).", "The French tried to do this after the revolution in 1789. They restructured much of their daily lives, like renaming the months of the year and restarting the calendar. Some things lasted longer than others, but keeping time with 100 seconds per minute/100 minutes per hour/10 hours per day was not one of them.", "I read somewhere once (don't remember the source) that it has to do with our Gregorian calendar. Sort of irrelevant , but that's why Stonehenge has around 56? pits dug into the middle area. Had to do with their different form of keeping track of time. But that doesn't really explain why they still go by normal (as listed above) hours , time, minutes, etc.", "URL_0 Take a look at the first 4:30min of the video. He talk about highly divisible numbers. Meaning which numbers have a lot of divisible numbers. That's why we use 60. 10 is really not a good numbers for that. The only reason it seem more natural is because we count in base 10 and we count in base 10 because we have 10 fingers. That's also why the imperial system is in base 12, 24 hours in a day, or that we use 360 degrees in a circle.", "Because it's historically how they did it. When humans tried to count time a long time ago, they separated the circle the sun dial went around in 360 degrees, (6x60), and then each degree in 60 arc minutes, and each arc minute in 60 arc seconds. 60 has lots of dividers (2x2x3x5) so its a convenient number. This system dates back to ancient romans and Greeks, if not before, if I'm not mistaken. Then, in the French revolution, people did try to change it to decimal, when they invented the metric system. They made decimal clocks with hours 100 minutes long, and minutes 100 seconds long, decimal calendars with weeks of 10 days, etc. But they never managed to implement it fully before they got replaced with another government, and the old way to count time stuck even though the metric system stayed. Honestly I think they shouldn't have used base 10: they should've used base 12, just like inches and feet use, but make every unit of measurement use 12. It has more dividers than 10 (2x2x3) which makes for easier fractions and multiplication, and people were already used to it thanks to the feet and inches. Oh well."], "text_urls": [[], [], ["http://mathforum.org/library/drmath/view/65468.html", "http://mathforum.org/dr.math/"], ["https://www.reddit.com/r/explainlikeimfive/comments/5mext2/eli5_why_do_we_count_seconds_hours_days_and_weeks/"], [], [], [], [], ["http://rsif.royalsocietypublishing.org/content/10/86/20130475", "https://jochesh00.wordpress.com/2015/06/03/a-mothers-wisdom/", "https://jochesh00.wordpress.com/2015/09/01/evolution-growth-development-a-deeper-understanding/"], [], [], ["https://www.reddit.com/r/AskReddit/comments/3mknlr/if_hours_are_based_of_60_minutes_and_a_minute_is/cvfssu3/"], [], [], [], [], ["https://www.youtube.com/watch?v=2JM2oImb9Qg"], []], "score": [5552, 1399, 73, 26, 24, 10, 8, 7, 6, 4, 4, 4, 3, 3, 3, 3, 3, 3]}}, {"q_id": "5sjhc0", "category": "Repost", "title": "Why are humans the only species that needs to cook (most kinds of) meat to eat it?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddfksjg", "ddfki3d", "ddflfcs", "ddfjte7", "ddfk7s2", "ddfkijc", "ddflt0e", "ddgbrxo", "ddfv90w", "ddghox1"], "text": ["Short answer: Because we figured out how. Cooking meat allows us to extract about 15% more calories from it because of the denatured proteins. Similar for being able to mechanically digest it. So ground beef that's been cooked to medium has about 25% more effective calories than the same weight of uncooked roast. That lets humans be the efficient ape. Compared to Chimps (our closest relatives), we've got about the same amount of gut and about half as much jaw for twice the ape. Cooking food kicks ass. And this is even skipping over the huge gains that we get from our ability to take \"questionable\" (read, not really questionable, but almost certainly full of Trichinosis) meat and make it fully safe by sitting it over a smoky fire for a few hours. Really, it may not be necessary to cook your meat, but it's so much better that it's no wonder the thermivore ape kicked the ever loving shit out of the omnivore apes when it came to competition for environment suitable for living/fucking/fighting.", "We don't need to cook meat. You can eat it raw if you want so long as it's fresh. Humans were just the only ones to discover cooking meat prolongs its life and makes it easier to digest, which in turn allows us to absorb nutrients better. You can survive just fine on raw meat. You can't do it on week old raw meat though and our food system is designed so that the majority of meat people have access to or will use is old enough for it to be unsafe or at the very least risky to eat raw (because it's assumed you'll cook it).", "Humans don't need to cook meat. Freshly butchered meat is reasonably safe raw, unless it has parasites. And that is the same risk other animals take when they eat raw meat. Humans cook meat because: * it kills parasites * it preserves the meat * it makes more calories available from it * because we can", "We don't need to cook meat to eat it. This should be obvious what with all the sushi restaurants. Cocking food makes the nutrients more available for our digestion and clears out many parasites so it became the norm. It is not required though.", "Cooking food has allowed us humans to take on more calories in a shorter amount of time. Cooked food, e.g vegetables, are easier to consume, digest and absorbed into the body. Hence, unlike cows and other animals that has to spend the entire day grazing on the fields to meet their daily calorie intake, humans just need a short period of time (breakfast, lunch and dinner) to have sufficient energy. On top of that, cooked food reduces the odds of getting food poisoning.", "We don't when we have a fresh kill. The issue is that we do not eat meat within minutes of killing the animal, we kill it days or even weeks before we consume them and ship them about the world and buy them in grocery stores. That allows bacteria to grow and that bacterial growth is what will make us ill.", "Because we don't have the flora needed to neutralize the excess bacteria/parasites in raw meat.", "Besides some of the replies here, it also saved us a bunch of time in the day, allowing us to pursue other interests. Most other animals spend much of their waking hours chewing and eating. Watch Cooked on Netflix. It deals with this very concept", "Reading all of these correct answers, something else occurs to me: Because it tastes better? Sure you get more calories from cooked food, but in the end, I think the driving factor for the first couple of thousand years was that a cooked piece of food usually tastes a lot better, and who doesn't choose that?", "Because we are actually an alien species and Earth is not our natural habitat. Think about it. Why do we need cooked food or clothes and shelter when others species just sleep outside. Why do we need all this infrastructure and overhead just to exist on this planet. We are the most foreign thing compared the rest of the planet and its inhabitants."], "text_urls": [[], [], [], [], [], [], [], [], [], []], "score": [422, 151, 64, 36, 13, 8, 4, 3, 3, 3]}}, {"q_id": "5sl0yq", "category": "Repost", "title": "bose-einstein condensate", "title_urls": {"url": []}, "selftext": "What is it? How is it made? What practical applications does it have? What's it's history?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddfu7uw"], "text": ["A Bose-Einstein condensate is a very special phase of matter which certain elements and compounds are thought to be able to enter. One which is known to be able to enter it is helium-4, which we call superfluid (slightly different but closely related) when it does so. The origin comes from statistical and quantum mechanics and can be a little complicated but I'll try to give a breakdown. **Fermions vs. bosons:** one way to categorise particles is by their spin. Spin is an intrinsic property of particles (like charge or mass), and goes in units of 1/2. Fermions are particles which have half-spin mutliples (e.g. 1/2 or 3/2), whilst bosons are particles which have integer spin multiples (e.g. 0 or 1). Spin belongs to elementary particles like electrons with spin 1/2, or photons with spin 1, but also to composite particles like atoms. As an example, helium 4 is composed of four protons, four neutrons and four electrons, each with spin 1/2. But these spins pair up and align against each other (e.g. two electrons pair up, one has spin +1/2 and one has spin -1/2, so the pair has a total spin of zero). This means that even though helium-4 is made of fermions, it is itself a boson. **Quantum states:** quantum mechanics tells us that particles live in something called a state. The state has a defined energy (among other qualities). The lowest energy state is called the *ground state*. **Statistical distributions:** fermions and bosons follow two different statistical distributions (Fermi-Dirac and Bose-Einstein respectively). These tell us how ensembles of these particles behave. The long and short of it is that fermions can't share the same state, whilst bosons can. With these things in mind, lets consider an ensemble of bosons (e.g. helium-4). What happens when it cool it right down towards absolute zero? Well at some point (for helium-2, about 2.5 kelvin), all the particles drop into the lowest energy state, the ground state, from all the states above. We now have a state of matter in its lowest possible energy configuration. That's why Bose-Einstein condensates from. It's tough to explain without a bit of quantum mechanics. You make it, as said, by cooling the right kinds of particles down to the transition temperature for it to happen. In terms of history, Bose-Einstein condensates were predicted in 1924-25, then superfluid helium-4 was experimentally made about 12 years later. It finds applications as a quantum solvent, letting scientists study particles as though were in a gas; in high-precision gyroscopes, and in cooling devices when things have to be cooled to extremely low temperatures. Superfluid helium-4 was also used to slow down light, effectively trapping it, in an experiment in 1999."], "text_urls": [[]], "score": [21]}}, {"q_id": "5sl6zu", "category": "Repost", "title": "Is Aspartame hazardous to your health? I use to believe it wasn't but has that scientific consensus changed?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddfvl2g"], "text": ["Aspartame is probably the most heavily tested and verified safe food additive that exists. At various times conspiracy theorists and hypochondriacs have accused it of being dangerous but they have always been at odds with science."], "text_urls": [[]], "score": [6]}}, {"q_id": "5slhqv", "category": "Repost", "title": "In these sanctuary cities, Why are the Mayor and city council not being charged with aiding and abetting a criminal, and harboring a fugitive?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddfwxl4", "ddfx7nb"], "text": ["They aren't actually breaking any laws or (legally speaking) aiding and abetting anyone. They're just refusing to do the Federal Government's job for them. It's not up to individual local governments to enforce federal law and they can't be forced to if they don't want to. If they were actively preventing federal officials from entering their cities that would be a different story, but that's not what they are doing.", "A few decades ago, the federal government passed a gun control law that mandated that local sheriffs enforce federal gun licensing. The sheriffs refused, and took the case to the Supreme Court. The Court decided that the federal government didn't have the right to force states to use state resources to enforce federal laws, and invalidated that part of the law. Same thing applies here. The feds can't make it a crime for state police forces not to enforce federal law, at least not without some legal maneuvering that has yet to be tried. Also, I would add, I'm most cases this wouldn't be aiding and abetting or harboring a fugitive. Those are usually very specific charges that require more than not giving someone's immigration status to a federal agency."], "text_urls": [[], []], "score": [8, 4]}}, {"q_id": "5smioq", "category": "Repost", "title": "How does the physical infrastructure of the internet actually work on a local and international level to connect everyone?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddgknvs", "ddgb9s4", "ddgbae1", "ddgmcwf", "ddgo9rt", "ddg8g3l", "ddg7ipr", "ddghyyo", "ddgetgb", "ddgo3w3", "ddgbuww", "ddgdyi2", "ddghgq5", "ddgn3k9", "ddglxvn", "ddgbkns", "ddh692f", "ddgn4yu", "ddgij0s", "ddh27m7"], "text": ["The coaxial (cable)/twisted pair (ADSL) leaves your house and goes to a building that's nearby (a mileish) called a Central Office (CO). These cables are buried underground, usually down the street in front of your house or alleyway, or carried on poles if you get your telephone or cable that way. In the CO all of the copper lines from all of the houses in the area come together and are plugged into some devices there. The step from the local office to your house is called the \"last mile\". These devices detect amplitude (how big) and/or frequency (how often) changes in the voltage on the line and convert it into digital data (ones and zeros). This process is called demodulation. From here your data is lumped together with all the other data coming into the CO and sent over a fibre optic line, usually buried under the street or hung on a pole, to a big data center where your ISP's routers are. Fibre optics can go very far, so there are usually only a few of these big data centers in a city. These data centers are physically connected to one another with buried fibre optic cables, and then one or more of the data centers in each city are directly connected to one or more of the data centers in neighbouring cities. So the fibre goes from your neighbourhood CO a mile or so away to a much bigger building somewhere in the city, which then has connections to other data centers in the city and in neighbouring cities. Electrical signals are converted into light using a transceiver. The light then bounces down the fibre optic line to the transceiver on the other end, where it's turned back into electrical signals. In the data center your ISP's routers look at the data. Routers are responsible for moving data between different networks. They look at the destination IP address and figure out which IP network the data is destined for. Then they look at these big tables (500,000+ entries) that match each IP network to an ISP based on the ISP's autonomous system number (ASN), which is how the internet sees an ISP. You see \"Verizon\", the internet sees ASN 701. Having it's own ASN, and having a copy of the table listing all of the IP network to ASN assignments is basically what makes an ISP an ISP (well, that and connecting to other ISPs). Once the router knows which ASN the data has to go to, it looks for the edge router that is closest to the destination ASN, and then sends the data bouncing through its data centers, city by city, until it gets to that edge router. More about edge routers later. ISPs connect to one another by burying fibre optic cable from one of their own data centers to an internet exchange (IX), which is a place where a bunch of other ISPs have agreed to drag fibre lines to as well. For obvious reasons, ISPs will also just designate one of their own data centers a Point of Presence (POP) and \"allow\" other ISPs to bring fibre cables there and rent rack space in the building. ISPs themselves, or companies that specialize in this, will also sometimes bury cables directly between IXs and POPs that are far apart (e.g. on different continents). These connections can be very, very long and very, very expensive. They will bury it over land or sea, farmland, forest, mountain, coral reef or deep ocean. These lines are usually one big continuous unbroken link, minus a few repeaters/amplifiers/regenerators which keep the signal strength up, and go for thousands of miles. In an IX or POP, which is basically a warehouse, each ISP is given space on computer racks in the building. So your ISP has brought their fibre optic cable hundreds of miles from their data center to the IX or POP and routed it through the building to their racks. They then place their edge router in the rack and hook up their backhaul fibre cable to it. A physical fibre optic or copper cable is then ran from your own ISPs edge router, through the building, to the other ISPs edge router, which is connected to its own long distance fibre cable back to that ISP's data centers. ~~And that's how babies are made~~ Edge routers tell whatever ISP they are connected to which IP networks your ISP owns, and then, importantly, they also usually say which additional ISPs your ISP is connected to as well. ISPs will then sign agreements between themselves regarding how much, if anything, they will charge one another for data going between them, and whether or not they are allowed to send data only to that particular ISP, or if they are allowed to also send to ISPs that THAT ISP is connect to as well. This is called peering. It should go without saying, this is a huge simplification and stereotypification of something that can go a billion different ways. One usual variation is that there are companies that specialize in burying fibre optic lines between IXs and POPs, so that if ISP A wants to talk directly to ISP B, but is far away from ISP B, they can pay to use part of one of these companies fibre lines to get from an IX where ISP A is to an IX where ISP B is, rather than paying to construct their own long distance cable. *Edit* I realize this is more of a ELI 1st year college student... but there you go... *Second Edit* Obligatory thank you for the gold, kind stranger. May your internet be forever fast and reliable... *Third Edit(s)* Good points from some great folks that newer implementations of DSL move the aggregation point (where your DSL line ends and your data is sent onwards over fibre optics) much closer to you and it is likely just a cabinet down the block. This makes things faster for you. Also remembered what a CMTS was, corrected a few typos, and added a few terms.", "Cables , there are literally cables circling the world under the sea. Smaller cables go to your house but ultimately connects with them. Satellites also exist on the Internet network of cables connected by sat dishes plugged in This is the simplest I could think to explain it to give a mental picture of it. Think there is no difference in small to large scale connections just think of it bigger", "Of course there is more to it than this, but it gives you an idea of routing and priority. When visualizing the routing protocols I try to turn it from data packages into real packages (mail), imagine this scenario. There is a post office at each local, city, region, country. **Case 1** The example address of 3805 S Keystone Ave, Indianapolis, IN 46227 USA going to 1400 E Hanna Ave, Indianapolis, IN 46227 USA. When the letter is given to the clerk at \"Indianapolis, IN 46227\". They recognize that the destination is already from their routing point and just puts the letter back in the out box. The local mailman knows about \"1400 E Hanna Ave\" and proceeds to drive to the destination. **Case 2** The example address of 3805 S Keystone Ave, Indianapolis, IN 46227 USA going to 87-135 Brompton Rd, Knightsbridge, London SW1X 7XL, UK The clerk at \"Indianapolis, IN 46227\" sees this is for a different City and sends it up to state level. The clerk at \"Indiana\" sees this is for a different country and sends it up to the National level. The clerk at \"USA\" Sees this is for \"UK\" and then sends it to their routing hub. From there \"England\" down to \"London\", then finally to \"Knightsbridge\" Which hands it to the mailman that goes to 87-135 Brompton Rd for delivery. **Edit:** Adding a data visualization of the [Internet backbone]( URL_0 #/media/File:Internet_map_1024.jpg) from the [wikipedia]( URL_0 )", "Network engineer here in the Portland, OR area. Internationally, you have few grade 1 providers such as L3 networks, XO communications, ATT, Verizon, etc. Pretty much old school telco providers that have the scratch $ to invest in high speed cabling. Most of this cabling is fiber optic bundles of a few strands to several thousand strands. Each pair of strands can currently carry up to (theoretical max at this time) 255Tbit per second, but most pairs are currently carrying 100Gbit and are aggregated together into a single connection for trans continental or trans oceanic crossings. They essentially hop along the shortest path of each respective network from router or Layer 3 switch (which is also a type of router) to the next and often utilize border gateway protocol (BGP) and Open Shortest Path First (OSPF) which is are algorithms that find the shortest paths on networks. BGP is self healing and automatically detects accidental fiber cuts or outages due to hardware failure. Think of these as \"upstream\" networks as most international traffic terminates at these types of carriers. Going down to more the local level, there are usually major network hubs in the world. Examples of this are: Seattle, Portland, San Francisco, Los Angeles, New York, London, (Fortaleza, Brazil), (Seixal, Portugal), (Mumbai, India), Hong Kong, Tokyo, (Pusan, S. Korea) etc. There are more worldwide, but I only usually deal with US based carriers as my work only serves US needs since it has to do with a national healthcare network. These terminate all of these high speed connections to lower level providers like your Comcast, Time Warner, ATT, British Telecom, Telekom, etc. distribute their private and public networks which then resell the upstream bandwidth to individual customers. Here in Portland specifically, there are roughly 2 single buildings that if, were destroyed would probably knock the whole state of OR offline because almost everything downstream flows through them and are the terminus for most of the networks from CA and WA and far east. This reselling of bandwith is sometimes done on an oversubscribed method. They sell more than they have. This is where you get into instances of \"slow\" internet locally and used to happen a lot more than it does now, but is still an issue in a lot of places. The carrier simply does not purchase enough upstream bandwidth to carry all of their customer's data. This is where caching nodes come in, such as Akamai, Amazon cloud, Microsoft Cloud, Netflix etc. These are geographically disbursed data centers that basically have local copies of all content on the internet that people are trying to access. For instance, someone in San Jose, CA wants to Netflix \"stranger things\" they get it straight from Netflix's data-center near San Jose. But then Joe in the UK wants to watch it, that data is sent from San Jose to somewhere in London to a cache node at super high speed and then stored there. Joe doesn't notice this but now that it's stored locally in London's cache node, everyone else on that node has access to it without having to make additional pulls from the original and thus slowing down the internet as a whole. Some 3rd world countries that have extreme restrictions on what their people can access, such as North Korea, use deep packet inspection and firewalls to say what people can access. This also results in them usually only having one single point of internet coming into the country which can be knocked out easily if someone gets out with a backhoe and digs up the fiber cable. EDIT: forgot OSPF and little odd and end items", "This is complicated. There are lots of different things going on at the same time. The analogy with letters by /u/Atzen doesn't really match how it works, unfortunately. It's a little more like phone numbers and a phone book. But I'm going to strip out the analogies. **DNS:** Let's start with typing in something like URL_0 into your browser. A certain part of that, URL_1 , is the *domain name* which tells you which computer has what you're looking for. But the domain name is not enough, it's like knowing a person's name. What you really want is something like a phone number or address. The post office doesn't know how to deliver a letter to \"Joe\" and the phone company doesn't know how to route a call to \"Joe\" either. So the first step is to look URL_1 up in a directory and you get an IP address, like 192.168.200.5. Now you can send packets of data to that address. **Routing:** So your computer sends a packet to 192.168.200.5. Let's say your computer has an address of 10.1.2.3. First, it checks if the address is on your network. Maybe your network has addresses like 10.X.Y.Z, but 192.168.200.5 doesn't look like that, so your computer needs to send the packet to a router that will send it to the right network. Maybe the router has address 10.0.0.1. So your computer sends a packet to 10.0.0.1, with the instructions \"please send this to 192.168.200.5 for me\". Your router is dumb, and only knows that it should send everything over your internet connection to your ISP. At your ISP, there are some smarter routers. One of them will get the packet, and look at it, and say, \"I know where the 192.168 network is, I'll send it that way.\" Your ISP isn't connected directly to that network, so it takes a few hops and visits a couple more routers along the way. Later on, a router might say, \"192.168, that's me! Actually, 192.168.200 is its own network, but I know where that is\". Eventually, you'll get to the 192.168.200 network, and the router will just send your packet straight to its destination. Each router only has a little bit of information. (There are other ways to route packets\u2026 sometimes you take a smart router, have it write some instructions on a packet, and then send the packet to a bunch of dumb routers which just read the instructions written on the packet.) If you want to see exactly which routers you use, try running a terminal command like `traceroute URL_1 ` **Connections:** Routers are connected to each other mostly through fiber optic cables buried in the ground. This is super expensive but very fast and reliable. Some connections go across the country, or across the world, and some connections just go to other parts of the city. They mostly work the same way: you take a router, give it a little bit of information like \"192.168 is that way\", \"10.0 is over there\", \"172.16 is behind you\". However, it gets a fair bit more complicated when you realize that for every router and piece of fiber optic cable, somebody *owns* that piece of equipment, and wants to get paid for letting you use it. The way it works is each company builds out their own networks, and then the networks get connected to each other at special places. So maybe I have my own network, CoolNet, and I run fiber optic cables from Seattle to Portland, San Francisco, Los Angeles, and San Diego. Then another company, AwesomeCom, runs a cable from San Francisco to Reno to Salt Lake City. If you're Kirkland, WA and make a video call (Facetime / skype whatever) to your uncle in Provo, UT, your packets goes through a few networks. * First, it goes through your home WiFi network. * Then it goes to your ISP's network. Your ISP has a bunch of cables going from their buildings to their customer's houses, and a cable which goes to Seattle (plus a few backup cables). * Once in Seattle, it goes to what's called a \"colocation facility\". It's a building, or maybe a couple floors of an office building, where everybody connects their networks together. Your ISP has a cable that goes here, and they have a router inside the building. They rent space from the colocation owner. The colocation facility has its own little network inside. * Since CoolNet also has cables going to the Seattle colo facility, your packet now goes through CoolNet. I can't connect you to Provo, but I can send your packet to another colocation facility, this one in San Francisco, CA. * Now AwesomeCom carries it to a colo facility in Salt Lake City, UT. (AwesomeCom and CoolNet are both huge networks, so we have a \"peering\" agreement where we can just send packets through each other's networks for free, since it's good for both of us.) * And your uncle's ISP carries it to Provo, UT. * And your uncle's router will send it to your uncle's iPad or whatever. If you are running a business and want a website that's easy to access, a great way to do that is put your computers inside a colocation facility. That way, your servers will have like 20 internet connections, instead of just one or two, and it will be easy to access.", "To get internet across the ocean there's these giant cables underwater that transfers the information physically. It's impossible to do that wirelessly without satellites and satellites are way more extensive than the cables.", "There is no difference between local and international. The internet knows no borders like we humans do. However different devices and protocols are used for different scales. BGP is what drives the internet on really large scales, it decides where certain IP addresses are (blocks to be more precise). Different peers (entities) decide at forehand where stuff should be. These really large routers keep track of these locations. The big traffic is mostly moved over fiber and satellites owned by private corporations and some gov. here and there. The cross Atlantic fiber optic cable is a good example of this. Then it arrives at the ISP's (and big corporations). They have their own internal network which uses different technology to move the traffic. These are the people that provide the connection for the \"home user\" Be it mobile network or broadband connections etc. The ISP makes sure you have a connection with them and they make sure they have a connection with other ISP's (this is a simplification) I could expand on this for a long time but I think this will cover the basic idea.", "There are 2 kinds of 'addresses' (that is, something that uniquely identifies a device). At a local and directly connected level (or level 2), you have the MAC address. Every device in the world has a different MAC. This helps 'packets' (of info / data) be sent at a local level. Next, you have your public IP address. If your MAC is your house number, your public IP is your street name and post code. This is referred to as 'level 3' routing Finally, you have your private IP. This would be like an individual person. Like in real life, people might have the first name and last name, but generally never in the same house. A device's private IP (like 192.168.x.x) is not unique, but it's unique to your house, and identifies your device. Now, imagine you live in America and want to Skype some one in Australia. Your PC can't find the IP address it's looking to send a packet to locally, so it uses its mac address to send it to the router. The router, too, can't find it directly connected to itself, so it uses a DNS server (which is like a road map) to see where to send it. It will then send the packet to the next-best router, and this will repeat. While the destination MAC address changes each time (as it is used to route locally), the destination IP doesn't. (E.g, while driving from place A to B, the road you drive on changes, you can only go on roads connected to yours, but your destination is the same). Finally, the packet will arrive at the right router (your house's private IP ), and will send it to the device it was destined for. For all of this to happen, there needs to be a connection (be it copper, fibreglass or wireless / satalite) from end to end, and way that this info is sent depends on each kind of medium used. If you were to travel by sea, you'd use a boat. If you were to travel by land, a car would do. Similarly, a router will determine how to send the packet, depending on the medium of the next router (or next 'hop').", "At the physical layer (aka layer 1), transoceanic fiber optic cables owned and operated by service providers (some private, some government). This video, although a little old, does a great job of explaining layers 2-4 at a level that most people understand. URL_0", "As far as the global internet infrastructure is, A device can connect to the internet and transmit data via an **Internet Service Provider** or **ISP**. Some examples of ISPs would be companies like Verizon or AT & T (these companies provide in the U.S.). These ISPs house their own data communication facilities called **Points of Presence**, or **POPs**, in local regions. These POPs just houses racks of routers and modems. Each POP gathers the data received from local users' devices and transmits this data further out in the internet infrastructure. And this works vice versa - POPs receives data from further out of the internet and sending them to their locally connected devices. The POP's functions are analogous to those of a local post office, but by using [modems]( URL_3 ) and [routers]( URL_0 ). The physical means for the data to travel between device and POP and then onwards, I'm not sure, but it varies depending on the existing local infrastructure and what the ISP can make use of. So what happens beyond the POP? These POPs, which belong to ISPs, are linked together with other POPs from other ISPs (by, again depending on the existing local infrastructure) along with data centers owned by governments and large organizations, at **Internet Exchange Points** or **IXPs**. IXPs houses [network switches]( URL_7 ). Just as POPs are like local post offices, the IXPs are like the larger sorting offices. (No single organization owns an IXP. The ISPs and other participants voluntarily agrees to link together for the sake of serving their customers and lowering costs, practicing what is known as [peering]( URL_1 ) . **You can check out an interactive map of the IXPs around the world by TeleGeography [here]( URL_6 )** The IXPs are then connected to other IXPs through [internet backbones]( URL_4 ). An internet backbone is made of fiber optic cables serving as principal routes for data to transmit at high capacity. Many of these fiber optic cables - [more than 550,000 miles of cable - are buried under sea to connect IXPs worldwide]( URL_2 ). **You can check out an a interactive map of the undersea fiber optic cables [here]( URL_5 )** also by TeleGeography. **TL;DR** **Globally: From device to local Point of Presence(racks of routers and modems) via an Internet Service Provider, to Internet Exchange Point(racks of network switches), to an internet backbone(under sea fiber optic cables), is how information is sent. Then from the internet backbone, it is received at a different IXP, POP, and finally device somewhere else on the globe.** Another key aspect of the internet infrastructure is how the information is sent \u2013 for example, a data file is not sent whole like mail. You should look up **I.P. address** and **data packets.**", "Why do I have to pay long distance to call someone one state over, but can communicate with someone in Korea over the Internet for free?", "It's a lot like how cars and planes move people around. There are streets that connect houses to other houses or to the city, cities are connected with highways or interstates, etc. There's no one road that everyone connects to,but the combination of all roads connects everyone (even if some are closed sometimes).", "Imagine those Russian nesting dolls.Matryoshka The one in the center has the data you are sent. The one that contains it has your house number. The next one has the street The next has the town name/zip or postal code The next has the state/province The next has the country. So the data is encapsulated in layers. When you have data to you it gets to your country border and that layer is peeled off. Next it gets sent to your town and that layer is peeled off After that it gets sent to your street and that layer is removed until it arrives to your house and the data is handed to you. The sorting and shipping process is handed by exchanges, routing equipment and switches. I know it is vague and messy but I am on my phone.", "There are a few ways. There are boats that actually put cables under the sea, and these cables carry our internet across the world where land isn't walkable. From the ISP to your home, from the ISP to other ISPs, from one nation to another - Cables are the most common connection. Other options are Satellites. We use satellites to 'bounce' signals off of so that we don't have to lay cables. Satellites come with a delay though - the travel time for the signal is very long, so doing things like gaming, two-way video, etc are all slowed down, or unusable. This is commonly how the US Armed Forces get their internet in the middle of no-where. (including at sea!) Then there is shortwave. Things like \"cell phone internet\" and radio towers. Microwave towers (those giant sea-shell/drum-shaped items on towers? Microwaves!)We use microwave towers to beam signals across the earth when laying cables across the same expanse is too costly, or impractical to maintain. We can also use cell phone like internet from these towers. These towers can be expensive to set up, and are often used in mountainous places. When you access URL_0 from the UK, you go over copper wires from your house (or over the air to your cellphone tower), to fiber wires at the street, to your ISP. These go over more fiber-wires to the oceanic coastal ISP who has a trans-atlantic cable. Your signal goes over this cable. Then it goes over more fiber cables in the US until it reaches the datacenter in the with URL_0 on it. It goes from the fiber back to copper at this datacenter (or maybe staying fiber) and connects to a physical box that serves of URL_0 for you. Then the data goes back to you. This travel process (forward and back) takes < 500 milliseconds. If for some reason any of the connections on the way to reddit and back stop working, the internet is designed (where the term web comes from) to use another route that exists, just like you being able to take another road when one is closed. Here is a website showing you how the world connects by wire! URL_1", "This question is very broad, but I'm going to focus on routing, or how the devices know which way to send traffic. I'm also going to focus on the large scale (network to network) instead of how the packet moves around within the network. In other words, I'm going to focus on how data might go webhost-provider - > Level3 - > Spectrum (my ISP) and gloss over the fact that someone like Level3 is actually made up of many devices internally. There are two basic problems. We need some sort of address for destinations, and we need some sort of way to know which direction we need to send data for it to eventually reach the destination. Addressing is actually pretty simple. We just use numbers. To keep it simple, we assign out these numbers to networks in large ranges. When you see people talking about IP addresses, those are the addresses, and when you see subnet mask, that is the range. Even though IP addresses and subnet masks are presented to humans as 4 numbers each, they are each actually just one large number that is being converted to 4 small numbers to make it easier for humans. So, the IP address identifies a specific destination, and if you add a subnet mask you can express an entire range of destinations, and you only need two numbers to do this. The second problem to solve is how everyone knows how to reach everyone else. Each large network has routers that use a protocol called BGP to communicate this information. Since IP and netmask together make up an entire range, routers don't need to remember every single IP. They can think (and speak to each other) in large ranges. When networks connect, they trade the entire contents of their BGP routing table. This table contains all of their own ranges and also all of the other ranges they heard from everyone else they connect to. If a network hears the same range can be reached by two paths, it picks the best one and puts only the best one in the table. In this way, every BGP network on the Internet has an entry for every single range that any ISP in the world says can be reached through them, and that table also says which connection is the best path. The table is big and growing: URL_0 For the most part, the big BGP routers on the Internet will have that entire table in their memory. At this point, we've established a system where everyone has an address, those addresses can be expressed in large ranges, and every network has a lookup table that contains every range and which direction to hand off the data for that range. So, the actual process is simply to receive a bit of data (a packet), look it up in this table, and then hand it off in the direction indicated by the table. When that packet reaches the next network, it simply repeats the exact same process of looking up the destination in the table and sending it off in the direction indicated. Source: Am a network engineer. I'm currently sitting in a room with the people who run the Internet. Well, most of them, and in North America at least. :) I'm at the NANOG meeting in Washington, DC.", "The internet is routed. Each router in the network only cares about its connected devices and their addresses. When a packet comes along the router only knows to hand the packet off in the correct direction.", "Play a game with your classmates. The rule is that you all can only pass messages to your neighbor and only the teacher can pass the message to the other classroom. Each class room is a country. Your classmates are local.", "Network engineer here, the internet is a combo bubble hyper node machinerator which coagulates the modems and transmogrifies them down the super information highway -- essentially a series of tubes. A common misnomer for internet infrastructure is that it's similar to a large van or lorry that computers just dump things on. I can tell you it's neither of these things (i'm a network engineer, in case you didn't see before).", "The internet is a network of networks. A network is just someone with a bunch of computers with website on them, or a bunch of people who want to reach websites. When two networks physically connect they tell each other what's on their own network and other places they are conected to and can reach, with that informaiton they agree to swap traffic to get it to the right place. because every network is connected to other networks traffic can always find a route to where it needs to be.", "So many network engineers TTH for an ELI5! The ELI5 answer is that routers of varying capacities, from your cheap home modem to the big carrier grade devices , send packets across various media types towards the the direction of a requested destination. The \"internet\" has a converged addressing schema that provides instructions on how to arrive to a given address, a path. That explains the transit. Content is provided by warehouses that carry computers connected to the same network. These routers and addressing schemas provide knowledge on how to send information between you and those computers. Finally what really makes it the \"internet\" is the distributed global participation of adjoining sub networks. Or as /u/ollybee pointed out the internet is a , \"network of networks\". You need not concern yourself with the stupendous amount of minutiae in ever changing media types (fiber, coax, ethernet, w/e) or furthermore the varying capacities, models, or brands of routers. That stuff gets into the weeds and becomes off topic from your question as everyone's situation is different. Since all the routers are speaking common languages we don't need to concern ourselves about the media types except for on a case by case basis defined in requirements."], "text_urls": [[], [], ["https://en.wikipedia.org/wiki/Internet_backbone", "https://en.wikipedia.org/wiki/Internet_backbone#/media/File:Internet_map_1024.jpg"], [], ["http://www.example.com/cheese.html", "www.example.com"], [], [], [], ["https://youtu.be/PBWhzz_Gn10"], ["https://en.wikipedia.org/wiki/Router_(computing)", "https://www.youtube.com/watch?v=i5oe63pOhLI", "http://apps.washingtonpost.com/g/page/business/a-connected-world/305/", "https://en.wikipedia.org/wiki/Modem", "https://en.wikipedia.org/wiki/Internet_backbone", "http://www.submarinecablemap.com/", "http://www.internetexchangemap.com/", "https://en.wikipedia.org/wiki/Network_switch"], [], [], [], ["reddit.com", "http://www.submarinecablemap.com/"], ["http://bgp.potaroo.net/as1221/"], [], [], [], [], []], "score": [4985, 874, 366, 187, 133, 89, 28, 17, 15, 10, 8, 7, 6, 4, 4, 3, 3, 3, 3, 3]}}, {"q_id": "5sohcc", "category": "Repost", "title": "What would happen if every country in the world had the same currency? How would things change?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddgmfzr"], "text": ["Eurozone nations share a currency, so they can't individually print money to pay their debts. This is a major weakness; it means they sometimes default on debts, which nations such as the UK or US never will. A further problem is that the movements in the currency's value, interest rates etc. that best serve one nation won't be right for another. If the whole world had one currency, it would be like the Eurozone on a larger scale."], "text_urls": [[]], "score": [3]}}, {"q_id": "5splpa", "category": "Repost", "title": "Why is the majority of the world right handed?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddgwfdu"], "text": ["\"The right shift theory and developed by psychologist Marian Annett at the University of Leicester, suggests that a single gene increases the likelihood of being right-handed. \"The essence of my right shift theory is that there is a gene that helps to develop speech in the left hemisphere of the brain and increases the probability of right-handedness,\" Annett told LiveScience.\" There's a common myth that swords and shields are a huge factor (shield in left hand protects the heart, right hand to attack). But there's a lot of evidence that right handedness existed long before then."], "text_urls": [[]], "score": [6]}}, {"q_id": "5spv7s", "category": "Repost", "title": "Why can't we go back in time?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddh0bs5", "ddgxj0i", "ddgyvc9"], "text": ["This is an unsolved problem in physics. Really. The mathematical equations that describe physics generally work just as well backwards in time as they do forwards, so it's not immediately apparent why time only goes one way. If a system would do *this thing* going forwards in time, you can just flip the signs and infer that it would do *the opposite thing* going backwards in time. This sort of thing is at play in the claim that going faster than light would take you backwards in time. That's one way of interpreting the math, but it may not really have any material meaning if it's impossible to accelerate anything *to* the speed of light, let alone past it (doing so would involve an infinite amount of energy). The single-direction nature of our movement through time is known as the **arrow of time**. It's connected to the second law of thermodynamics - the idea that entropy always increases. But for a more fundamentally satisfying \"why\"? Good question. URL_0", "If I could add to this question. If time is considered an extension the three dimension onto a fourth, wouldn't putting something into the past take an infinite (or at least gargantuan) amount of energy?", "So you have a piece of paper, the topside represents the future and the bottom side represents the past. As these two segments of time are separated by the piece of paper itself, you can't really go back and forth from one side to the other. The only way to interact with the segments of time would be to poke a hole through the paper. Good luck poking a hole through the universe."], "text_urls": [["https://en.wikipedia.org/wiki/Arrow_of_time"], [], []], "score": [5, 3, 3]}}, {"q_id": "5sqib5", "category": "Repost", "title": "What happens when you \"get the wind knocked out\" of yourself?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddh38q9"], "text": ["It usually happens when an impact (be it falling or getting hit) temporarily paralyzes your diaphragm, making it difficult to collect enough air. It's called getting the wind knocked out of you because it *feels* like the impact forced all the air out of your lungs."], "text_urls": [[]], "score": [6]}}, {"q_id": "5srowe", "category": "Repost", "title": "How can gorillas and other herbavores get so big and muscular from a diet of essentially leaves and plants, while vegan humans tend to loose muscle mass on plant based diets?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddhdrkp", "ddhbuql", "ddhhl9q", "ddhdyso", "ddhd4f2", "ddhd08x", "ddhgv5x", "ddhgf28", "ddhgqhe", "ddhfof4", "ddhhygt", "ddhh6n4", "ddhi0bg", "ddhhhp9", "ddhh9o7", "ddhgxgc", "ddhivuq", "ddhj0yk", "ddhco1j"], "text": ["Nobody here has addressed the genetic basis and control of muscle mass and buildup in response to testosterone levels. One reason for example that a male gorilla simply builds muscle easily is because their muscles do not atrophy as easily and \"build\" with much less limitation for little exercise.", "Do people who follow vegan diets properly actually lose muscle mass? Because I don't think they do. There are people who eat tons of meat who have no muscle mass whatsoever. And humans and gorillas and other herbivores have a different physical make up... regardless of diet.", "There are a lot of misguided responses here, so I figured I'd add a little more science to some partially true responses. First: you lose muscle if you don't use it. The human body won't maintain above a certain level of fitness without constant stimulation, to save resources. Second: the great apes are omnivores. They eat bugs, and anything small enough that they can get their hands on. Often this includes rival apes, especially their young. Third: humans have a great deal of stabilizer muscles. We sacrificed raw strength for the ability to interact with the world with incredible dexterity. To address the misinformation... First: We can extract plenty of nutrients from everything we eat. However, the reason we treat food with heat (ie cooking) is to make these nutrients more readily available. We cannot break down the parts of plants that are incredibly tough (cellulose), but this is something that is rather exclusive to herbivores. it requires a great deal of specialization (like the cow and its four part \"stomach\") and a LOT of plant matter to be worth it. they also repeated grind and mash their food during digestion (chewing their cud). our bodies are very adaptable to different diets, especially during infancy. there are some incredibly interesting studies on human gut bacteria that are worth checking out here Second: you can live just fine on a vegan diet. many people need supplements, because it can be time consuming and expensive to get a complete array of required nutrients from just a vegetable diet alone, but it is very possible.", "One thing i feel the compulsion to point out is you listed gorillas specifically as herbivores and they are not Great apes ( gorillas, chimpanzee etc ) are omnivorous, while they do exist largely on a diet of fruits and vegetables they will not pass up adding insects and even the occasional small monkey to their diet if readily available", "People like [Patrick Baboumian]( URL_2 ), [David Carter]( URL_0 ), [Kendrick Farris]( URL_3 ) and [Billy Simmonds]( URL_1 ) show that humans don't necessarily lose muscle mass on plant based diets.", "Vegan humans don't lose muscle mass. Plants and animals share the same amino acids (as does all life) and therefore if you eat the right plants (or enough plant) you can get all of the nutrients you need.", "Gorillas aren't the only ones. Bison, cattle, elephants, and many other very large animals develop massive muscle and bone structure on a plant-based diet. Think about how large and powerful a horse is, and it isn't even one of the really big ones. Also consider that they all eat a TON of food and must spend most of their waking hours grazing. Humans don't have to do that. Gorillas eat about 40 lbs of vegetation every day. We'd die if we tried that. Our teeth wouldn't last. So even if there is less nutritional value in much of their diet, the quantity makes up for it. I don't know the scientific details, but their systems have evolved to metabolize the nutrients in their diet into powerful muscle and bone mass. We develop muscle and bone too, but obviously our conversion process is unique to us, just as it is with every other animal. I realize this isn't a direct answer, but hopefully gives you more to think about...", "I do not know how to say this without looking like a douchebag.. but I'm vegan and I have a LOT of muscle mass. Vegans have the skinny stereotype, but muscle mass really depends on metabolism body types (ectomorphic, endomorphic, and mesomorphic). Again, I'm not trying to be one of those annoying vegans who preach about what I eat, but the skinny vegan is definitely a stereotype.", "I think this is more of a question of culture and lifestyle than biology. There are flabby and weak humans who eat meat. There are vegan body builders who have significant muscle tone. Most vegans I've ever met do not work out. They would have muscle if they worked out.", "For my two cents worth, I'd say the largest difference is lifestyle. Humans of any sort live very different lives to gorillas. Gorillas just east, shit, bang and run around. Humans do the same, but with a lot more sitting down ( generally). Anecdotally, since going vegan and working out more, I have lost fat and weight, but my muscle mass is increasing If I just ate lettuce and didn't exercise, for sure I'd be skin and bone. But so would most animals", "> vegan humans tend to loose muscle mass on plant based diets Evidence? (Like actual evidence, not some gym bro gossip) Never heard this claim before", "It is all about net hypertrophy. The easiest way to answer this question is referencing the human mutation to the MSTN gene (myostatin-related muscle hypertrophy). Normally, humans atrophy at a greater rate than most animals for good reason, we are not a labor intensive species anymore. Myostatin is a protein encoded by MSTN that, when received on muscle cell receptors, inhibit muscle hypertrophy. The mutation to either the MSTN gene or the receptor that receives myostatin prevents this inhibition, causing full net muscle hypertrophy. You can see these effects in cattle, certain dog species, and even a handful of humans across the world (see worlds strongest toddler). Gorillas are genetically encoded to not go through muscle atrophy by limiting the amount of myostatin produced.", "What vegan humans tend to lose muscle mass on a plant-based diet?", "I mean as a vegan my muscle mass has gone up since I became one. I used to be baby fat pepperoni pizza body. Now I only have A little chub and muscle", "1000 calories of Broccoli is still 1000 calories. Might be 6.5 lbs worth, but the numbers are there :D", "Watch vegan gains if you are interested in learning how the body is supposed to be on a plant based diet, how the body is not built for eating meat, how the body can build muscle with plant proteins, and how to live a vegan lifestyle. Building muscle being vegan is possible and not hard at all.", "BACTERIA! I'm surprised nobody has mentioned the role of bacteria in converting plant matter to energy. When this question was asked in r/AskScience several years ago, the top answer was enlightening: URL_1 Look at a gorilla's stomach - it's a have huge fermenting vat. Also see [here]( URL_0 ) for an answer slightly above 5-year old level: > The gorilla has six times the absorption available from the colon than does the human, which also means they have many times the amount of bacteria available for digestion of plant cellulose. The high fiber in the gorilla diet is fermented by the colonic bacteria, yielding short chained fatty acids (SCFA). In other words, the indigestible carbohydrates are converted to saturated fat and absorbed into the blood. A human eating a similar diet would just end up crapping most of it out, receiving little benefit. > The gorilla can obtain about 65% of their energy from their hind-gut, whereas the human only receives about 10% from the colon. The butyrate created in the human colon is mostly used locally by the cells of the intestinal lining and only a very insignificant amount is absorbed. This is why a human can live without a colon and an ape can\u2019t. (see my post \u201cThe Planet That Went Ape!\u201d for more on ape vs. human gut ratio)", "I have been vegan for four years and I have never lost weight. As a matter of fact I gained 24 pounds. The mistake lies in thinking we only eat leaves and lettuce. But I don't blame you", "Pretty simple. True herbivores have the digestion system to handle such a diet. A herbivore has intestines up to 20 times their height/length. Human, like most omnivores, have about 6 times (so 30-35 feet for us). Carnivores have about 3 times. Herbivores are by far better suited to digest plant matter."], "text_urls": [[], [], [], [], ["https://en.wikipedia.org/wiki/David_Carter_%28defensive_lineman%29", "https://en.wikipedia.org/wiki/Billy_Simmonds", "https://en.wikipedia.org/wiki/Patrik_Baboumian", "https://en.wikipedia.org/wiki/Kendrick_Farris"], [], [], [], [], [], [], [], [], [], [], [], ["http://roarofwolverine.com/archives/1437?print=print", "https://www.reddit.com/r/askscience/comments/ow8tr/how_do_gorillas_manintain_their_large_muscle_mass/c3kk9nv/"], [], []], "score": [239, 104, 87, 51, 39, 38, 29, 27, 23, 19, 15, 12, 11, 8, 7, 6, 6, 4, 4]}}, {"q_id": "5ssuco", "category": "Repost", "title": "Why do subtle vibrations on the road put us to sleep so easily?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddhlxtu"], "text": ["Gentle rhythmic movements work just like rocking a baby to sleep. The road noise also provides a white noise effect that helps you tune out other city noises that might making sleeping harder."], "text_urls": [[]], "score": [3]}}, {"q_id": "5sw4di", "category": "Repost", "title": "Do cell phones really give you cancer? Is there enough supporting evidence to say if it does or not?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddia62x"], "text": ["If you are asking if the electromagnetic radiation transmitted and received by cell phones can cause cancer in living organisms, the answer is no. This is because the wavelengths used for cell phone communication are too long, which is another way of saying they are too low energy. There are different types of EM waves: Radio, Microwave, Infrared, Visible, UV, X-Ray, and Gamma. These are not hard cut-offs but general spans of radiation. Each category can do different things to atoms/molecules/nuclei. Here's a brief description of each. Radio waves: Nuclear atomic spin transitions (these have no practical every day use to lay people but are very useful in science). Microwave: Molecular rotational transitions which cause molcules/atoms to rotate/spin. In microwave ovens, this causes water molecules to rotate and when they bump into each other, this rotational energy is converted/dissipated in other ways (see next). Infrared: Atomic translational and bond vibration. This is generally what we perceive as temperature. Up until here, nothing too dangerous can happen. Visible/Ultraviolet: electronic transitions. What this means is that the electrons in bonds get excited. This generally makes molecules more reactive and they can go off and do bad things. Your DNA making random bonds with other things is not a good thing. This can cause cancer the more energetic the radiation is (UV or higher) X-rays: Higher energy electronic transitions. UV radiation generally deals with outer shells of atomic electrons. X-rays can excite/eject core shell electrons. The amount of energy imparted could cause molecules to break apart and at the very least generates very reactive states that can go off and do bad things. You don't want this happening to your DNA. This can cause cancer. Gamma Rays: This causes nuclear excitations. This is not like the spin state change in radio waves. This type of radiation excites protons/neutrons to higher energy states which can cause the nucleus to fission or dissipate the energy in other ways which can generate reactive atoms/molecules. Nuclei blowing up in your DNA is not a good thing. This can cause cancer. So in summary, the radiation sent/received from cell phones cannot cause cancer because the radiation sent/received is incapable of hurting your DNA."], "text_urls": [[]], "score": [3]}}, {"q_id": "5swk12", "category": "Repost", "title": "Why does air get cooler as it goes through a fan?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddid85x"], "text": ["This has been answered many times. It doesn't , the wind carries away heat from the skin which we feel/understand as cooling when in fact the room temp is the same. Even worse, the motor actually heats up a closed space :)"], "text_urls": [[]], "score": [3]}}, {"q_id": "5sxzxa", "category": "Repost", "title": "What is the dark web vs. deep web? How exactly do you get there? And how dangerous is it if you don't know what you're doing?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddipnai"], "text": ["the dark web refers to the part of the internet that requires using the TOR routing service to gain access. Once you have access it is much like the rest of the internet only generally targeted towards much more shady things and conversations that people want to remain anonymous for. the deep web refers to all parts of the internet that are unindexed, that is to say are not publicly accessible to just anyone. Every page and post on reddit if properly searched for can be found on google and therefore indicates that it is indexed. Companies have many web pages, documents, and data that require special credentials and logins to access. The deep web refers to all of these various pages and locations. If you're a member of a private forum that requires you to log in to see information, congratulations, you've been to the deep web and there is nothing dangerous about it. If you've downloaded the TOR software and connected, congratulations you've been to the dark web. the level of dangerousness is correlated directly with the activities and websites you visit, though largely harmless you may find yourself on a list at some government agency :p"], "text_urls": [[]], "score": [13]}}, {"q_id": "5sy33l", "category": "Repost", "title": "What creates gravity", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddit6i6"], "text": ["If you figure that out, enjoy your Nobel Prize. We can quantify gravitational force, but are yet to discover what causes gravity. The working hypothesis is that there are massless particles called gravitons that emit gravitational fields, but we've never been able to detect one."], "text_urls": [[]], "score": [5]}}, {"q_id": "5syfnt", "category": "Repost", "title": "When did humans start kissing each other & what was the initial purpose for?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddisxzy", "ddivaig", "ddj0ap8", "ddivwjl"], "text": ["Baby has virus. Mom kisses/licks baby. Mom gets virus. Mom creates antibodies against virus. Breastmilk contains antibodies. Baby survives to reproduce. This is the leading hypothesis, then most likely it was seen as a sign of affection and it blew up from there Edit: this may have been pre human and our primate ancestors did it", "Its believed that kissing is linked with the food needs of the baby birds and the way their mother feeds them. Im pretty bad at explanations, so heres a video where is explained pretty well. I hope i've been helpful! URL_0", "The most primordial instincts of any species are survival and reproduction. The mouth is one of the first organs to develop in the fetus. That's one of the first things that a baby learns to control, is highly complex and has a lot of nerves. We use the mouth for feeding, tasting, communicating, displaying emotions, sensing our environment and even attacking. The mouth is also a notable erogenous zone. Therefore, it's not surprising that it has a prominent role in social interaction. **When:** possibly as soon as our ancestral species developed affection. Many species interact socially with the mouth either by touching, licking or biting. Even birds interact with their beaks. Kissing itself is just another development of these actions. **Initial purpose:** I guess the purpose of kissing should have been always the same as today. And it's intimate nature certainly helped on the development of the immune system which emphasized it's survival role further down in the evolutionary process.", "Some scientists believe that kissing originated as a form of giving food to the kid. The mom chews the food for the kid and the kid eats it, just like how bird moms do. This creates antibodies in the mom which goes to the breast milk and that passes on to the child, making it stronger. Although today it's considered gross, it's not a bad thing if your mouth's clean. VSauce explains this very well: URL_0"], "text_urls": [[], ["https://youtu.be/ixQbCXLUUj8"], [], ["https://www.youtube.com/watch?v=ixQbCXLUUj8"]], "score": [51, 5, 4, 3]}}, {"q_id": "5syqe7", "category": "Repost", "title": "How did map makers make maps and know the shapes of the continents before satellite images?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddiuzms", "ddiyljo"], "text": ["Well, they didn't to be honest. The earliest map makers were elites at using compasses and measuring distances visually to determine the shape of a coast line or a river ect, but they never were to accurate. If you look up examples of old maps compared to sati lite imaging it's wildly different. Mapping the middle of the ocean would prove to be a lot harder though, some how they still did it. The early map makers could decipher there position on the globe by looking at the locations of constellations compared to the location of the constellations at home. All in all the people who made the maps spent their whole lives making them.", "On top of what the other commenters said, the United States maps were very accurate in the late 19th century because mountains and hills were used to develop a carefully triangulated network of reference stations, [see here]( URL_1 ) for the reference stations between California and Colorado. Surveyors were literally on top of mountain peaks with very heavy theodolites, supplies, and equipment for days on end, taking careful measurements of all the other reference stations over distances of 100-200 miles. If you dig around you can find stories of these surveys, they were often extremely difficult and surveyors sometimes got killed on these mountains. Using these triangulated reference stations, math and very careful measurements was what made the maps so accurate. Using these stations as reference points they could fill in the smaller scale details in the local areas. The British likewise had triangulation surveys... [here is one such map of India]( URL_0 ) in 1870. You can see lines extending northward on the top right side of the map. Nepal was off limits to the British, and these lines were attempts to measure the Himalayas from a distance, including Mt. Everest. These were all surprisingly good measurements."], "text_urls": [[], ["https://upload.wikimedia.org/wikipedia/commons/thumb/0/00/1870_Index_Chart_to_GTS_India-1.jpg/1068px-1870_Index_Chart_to_GTS_India-1.jpg", "http://i.imgur.com/Ynts7Ya.jpg"]], "score": [7, 4]}}, {"q_id": "5szbjp", "category": "Repost", "title": "Why were plants so big in prehistoric times but evolved to the size they are now?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddize6j"], "text": ["Back in dinosaur times, there was a lot more carbon dioxide in the air (like 5x as much). Plants literally make themselves out of the carbon in the air (they take in CO2, put out Oxygen during photosynthesis. They use the carbon they take in to build their plant body). As the atmosphere changed, there was less CO2, so there's less stuff to make plants out of."], "text_urls": [[]], "score": [9]}}, {"q_id": "5szuuf", "category": "Repost", "title": "If the Universe is 13.8 Billion Years old - How did it grow to be 46 Billion light years wide?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddj1tms", "ddj1lql"], "text": ["URL_0 Look at this video, it will explain well with visualisation. But basically, space itself is expanding. You can't really calculate the speed at which space expand, but you can use two point of reference (a star and our solar system for example). What happen is that every volume of space is expanding, so the more distance between these two object, the more volume of space there will be between the two, more volume that all expand, making the speed at which those 2 stars are getting further away faster. At some point, those two star are getting further away at the speed of light and it's at this moment that they emit the last photon we will ever see from earth. But space will continue to expand pushing that star even farther away. By the time the last photon reach us, that star will be even further away. The light from star 46 billions years away is the light that they emitted before they were getting away from us at the speed of light. And yes nothing can move at the speed of light in space, but it's the space that expand, dragging the stars with it.", "The growth of the universe is not limited by the speed of light. That is the speed limit inside the universe but the universe itself can expand faster"], "text_urls": [["https://youtu.be/gzLM6ltw3l0?t=6m50s"], []], "score": [6, 3]}}, {"q_id": "5t00rf", "category": "Repost", "title": "How exactly does an EMP disable electronics?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddj3a23", "ddj2kpy", "ddj38ko", "ddj6d9c", "ddj476j"], "text": ["This has been asked [a few times already]( URL_0 ). Here's one of the answers: > An EMP is simply a massive burst of EM. > EM is Electromagnetic Radiation. This is the generic term for Radio Waves, Microwaves, Light, UV, X-Rays, and Gamma Rays. All of these are fundamentally the same thing. They're all just photons given off by ions. But what they're called by us humans is determined by their wave-length (we call this color). > Your EMP is a very bright FLASH of a board spectrum of EM radiation (so radio waves, microwaves, etc.). This energy is Electromagnetic so it interacts with electrical hardware. This is how mankind is able to build cellphones, radio stations, fiber optic cables, digital x-ray machines, etc. > When you send out A LOT at once. You overwhelm the sensor frying it. If you send out EVEN MORE you make wires behave like antenna. This overloads an electrical circuits frying them.", "The simple answer is that an EMP causes strong electromagnetic fields that can cause a huge power surge in electronic components. It basically overloads and thus fries them.", "Every wire is an antenna. And if you send a strong enough radio signal you can create very high voltages though that antenna and damage any components connected to the antenna.", "I probably have a 5 yr olds understanding of this so here goes. When an electrical conductor moves through a magnetic field electricity is produced. This is how a generator works. You have magnets around a coil of wire and spin the wire around inside the magnets field. So if you have an electrical conductor and hold it still but move the magnets around, you still have a conductor moving through a magnetic field which creates electricity. So as the magnetic field moves away from the source of the EMP, every conductor it moves through will generate electricity. Look at a circuit board and imagine every line on the board having current run through it simultaneously at levels it's not made to withstand.", "So I'll let you in on a secret. You remember how big independent flashes on cameras have a weird beeeping sound after they go off? That's the sound of the flash \"recharging\" back to full capacity. It basically stores energy in a capacitor/inductor and then releases it all very fast once the camera's button is pressed. Similarly, in an emp generator, we gather a large amount of charge and discharge it quickly to create a pulse of energy which creates a massive current in the device you point it at, frying them up."], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/search?q=EMP&amp;restrict_sr=on&amp;sort=relevance&amp;t=all"], [], [], [], []], "score": [19, 10, 5, 4, 3]}}, {"q_id": "5t155i", "category": "Repost", "title": "Why do things physically hurt more when we are cold?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddjlcub"], "text": ["Your body is filed with thermoreceptors to detect the temperature. You have 2 main thermoreceptors for cold: regular cold thermoreceptors and extreme cold thermoreceptors. The second one, extreme cold, sends pain signals to your brain. So when it's cold and something hurts you, your brain is getting 2 different pain signals that compound with each other"], "text_urls": [[]], "score": [10]}}, {"q_id": "5t1rgi", "category": "Repost", "title": "If the universe is constantly expanding, what is it expanding into?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddjle41", "ddjgacm", "ddjgk4p", "ddkcoju"], "text": ["Let me get right to the point, the universe isn't expanding, it's stretching, and there is a difference. Expanding is a terrible word to use, but it's the easiest, shortest path to express to the layman through media the concepts behind what we observe, that everything is moving away from us in all directions. And it's not that things are flying away from one another like sparks of a firework being blasted away from each other, but instead that if the universe were a surface those sparks sat upon, it's that surface that is moving, carrying the sparks with it. For those who have the intellect to ask, \"expanding into what\" is a very reasonable and the logical conclusion. And you are correct for asking it. But that's the trick behind the concept of an infinite universe. Let us not forget that the \"Uni-\" in *uni*verse means *one*. Even the speculative \"multi-verse\" theory is still encompassed by one reality, and that is the universe. There again lies a slippery slope sold by the common media, because people struggle to even grasp the idea that you can have more than 3 dimensions at right angles from one another (learn what a matrix is in Linear Algebra to understand this), it's just easier to say \"somewhere out there, if you travel far enough, you might come across another universe.\" That's *really not what they meant*, but they also had to pull a scratch lottery in Alabama that was arctic themed because a significant number of players couldn't grasp the concept of what a negative number is... No, the universe is infinite, and fixed in size at infinity, and we're seeing a stretching. If you need an analogy, let's use the old inflating balloon. Instead of thinking about how it's being filled with air, and thus expanding into the adjacent space, the balloon is fixed in size and rather elastic - a balloon that's under inflated. If you draw some dots on the surface and then stretch the balloon just where the dots are, you will see that you get the same expansion behavior while the volume in the balloon remains the same size. And you can stretch the whole balloon without changing it's volume, if you just grab it by two ends and pull. The analogy breaks down because we necessarily have to manipulate the balloon in 3D space, when really it's only the surface and the volume of the balloon that are the important factors. There's a whole branch of math dedicated to this called Topology, and it's a very hot topic for math research.", "Nothing. It's just... expanding. Let's say you have a row of blocks. 5. You insert a block in between each. You have to spread - or *expand* - those blocks apart to make room. Now you have 9. Do it again and it expands again and you have 17. And so on. But imagine that row of blocks was infinitely long. You can still insert blocks in between making it \"longer\" (though it's still infinitely long). And instead of a row of blocks imagine a grid and you are expanding in both directions. Then imagine it in 3-dimensions and you basically have what is happening to the universe. Instead of blocks its space itself.", "It's easier to think of this in terms of time. Today is Feb 9 where I am. History is the time behind today. History is expanding at a rate of 1 day per day. It's not, however, expanding into something. It would be wrong to say that Feb 11 is \"there in history waiting to be observed\". We've agreed that we're going to label whatever happens Saturday with Feb 11 when the history is recorded.", "A new theory is actually evolving somewhat into a universal wobble, where the universe expands and contracts continuously. Wrap your head around that one. Basically, the current popular theory is that universe is expanding into empty space. Or maybe it's a single point that is not expanding and we are all just data in virtual space or a hologram or a simulation. Or the universe stays the same size and the bending of space due to gravity \"simulates\" an expanding universe and masses and energies distribute themselves throughout the universe. That's my personal favourite."], "text_urls": [[], [], [], []], "score": [11, 9, 8, 3]}}, {"q_id": "5t2pma", "category": "Repost", "title": "Why are precious metals still so valuable despite no longer being used as currency?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddjnz4t"], "text": ["Solely because people are still willing to spend so much to own them. Inherently they're worth nothing, they only have value because we say they do."], "text_urls": [[]], "score": [6]}}, {"q_id": "5t2sco", "category": "Repost", "title": "Why is black pepper nearly as universal as salt as a seasoning for savory food?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddjsyxu", "ddjwhlc"], "text": ["Peppercorns are easy to transport and keep fresh, which mattered a lot more in the Middle Ages to 1940. Because it was one of the few spices that was widely available, it became a staple in recipes.", "Black pepper acts as a flavor-balancer. Not every dish requires it, but dishes with stronger flavor profiles tend to benefit with the addition of a little black pepper. Let's take a look at a classic dish: strawberries and cream. Typically, the cream overpowers the strawberries. Adding a little black pepper helps balance the sweetness of the cream with the natural flavors of the strawberry. TL;DR It helps with dishes that can easily have imbalanced flavors."], "text_urls": [[], []], "score": [11, 8]}}, {"q_id": "5t411m", "category": "Repost", "title": "Why is there a flu \"season\"? Also, do other viruses and bacteria have time frames during which they are more active?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddjz02a"], "text": ["It's cold outside. Everyone goes inside to be warmer, and to avoid hypothermia. Now you have many people concentrated in a small area. Germs now pass along easier. Viruses die quickly without a host but now they can find hosts easily."], "text_urls": [[]], "score": [5]}}, {"q_id": "5t55h3", "category": "Repost", "title": "what happens to all those amazing discoveries on reddit like \"scientists come up with omega antibiotic, or a cure for cancer, or professor founds protein to cure alzheimer, or high school students create $5 epipen, that we never hear of any of them ever again?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddkhrio", "ddkcioh", "ddk9w0m", "ddkaryf", "ddkl7q6", "ddkg3xt", "ddkh442", "ddkhtyh", "ddkdone", "ddkbwie", "ddkhfmi", "ddkifdz", "ddkfxj7", "ddkj3ul", "ddkiv7y", "ddkjb76", "ddk8gfs", "ddkn2oe", "ddkbw7d", "ddka1ul", "ddkm178", "ddkgsqt", "ddkl3us", "ddkm5sk", "ddkgz5n", "ddkn5lr", "ddlky9w"], "text": ["I'm a scientist! So let me try to offer my insight: So first of all, like every other job in the world, scientists need money in order to work on their projects/research. Unlike \"regular\" companies though, scientists don't really *sell* anything, so it's going to be hard to go to Wells Fargo and ask for money without being able to show them how you plan on paying them back. Enter organizations like the National Science Foundation (NSF), the National Institutes of Health (NIH), Defense Advanced Research Projects Agency (DARPA), NASA, the European Commission, and the list goes on. These organizations have many purposes, and one of them is to allocate researching funding to promising projects. What they'll do is, for example, put out a \"call for proposals\" and then allow scientists to apply for funding. For example, the NSF might put out a call for proposal on the subject of say \"childhood education.\" So you're a scientist doing research in \"teenage education.\" You have a lot of experience on research in education in teenagers, and you think that you might be able to apply your work to education in children as well. You just don't have the time, or money, or staff, to actually do it. But now that there's this call for proposal, it's your chance! So you write a grant proposal which basically outlines what you are going to do, how you are going to do it, why you are going to do it, and a lot of other things are involved. Will your project involve any ethical considerations? You'll need to include documentation showing how you will follow ethical approvals, for example. You'll also need to submit some kind of budget guidelines. If you are requesting $500,000, how will this be used? $500,000 sounds like a lot, but in terms of research it's not really. The NSF might award you the grant for $500,000, but you need to keep in mind that this money is for the duration of the project. Do you need equipment (you will)? Do you need lab space (you do)? Do you need to hire new staff (you might)? New staff could be other researchers or grad students to help you. They need to get paid, after all, and so do you. In the end: my point is: we **need** money just like everybody else. But unlike Boeing, and unlike Intel, and unlike Apple, or Google, etc... the money that I am asking for to do my project, actually has no promise of monetary return to my investors. What I promise to return to the NSF, or to NASA, etc, is the promise of advancement in research. I do this by using the money to conduct experiments, and then publishing papers about it or giving talks at conferences. From the journal articles, other scientists will be able to follow my findings and either use it or try to test it etc and build upon their own research. From the conferences, I show things that are essentially \"works in progress\" but hey, maybe my idea is exactly what someone else was missing, and if they see me talk about it, they might come find me later on (or email) asking to collaborate. These are things that we *all* benefit from (we as in scientists), and these are essentially the \"returns\" that I promise to the NSF when I write my proposals. When I publish or talk at conferences, I am talking to my peers. I am talking to colleagues. I am talking to scientists. When I talk to my peers, I would never make claims like \"this line of research can, **will**, definitely improve childhood education by 500%!\" When I talk to my peers I am trying to discuss my work. But when I am talking to media (be it the press, a TV program/interview, Twitter, my personal website/blog, message boards, or my university's press office, or hell, even my own non-scientist friends and family), I am not trying to discuss my work. **I am trying to sell my work.** I want to sell my work because, like I said, my work is entirely based on receiving money. Without money, there is no research, period. So I might exaggerate a tiny bit, or trump up all the benefits of what I'm doing and then throw in a very minute detail about how those gains are the theoretical maximum assuming that all the planets are aligned. I'm not really lying about anything, I'm just giving a, perhaps very, optimistic view of my research. (After that, the journalists usually run off with it, and replace words like \"could maybe\" or \"might possibly\" into \"will definitely\" and so on.) When I apply for funding, I like to think that the system is merit based, as in they'll review my track record and past research and so on. In general this is more or less true. So I'm not actually trying to sell my work to these agencies like NSF etc. Who I'm trying to sell to is to both the tax paying public and to the politicians in charge of appropriating money to the NSF. Since I am not making anything, or selling anything, I need to convince the public that their tax dollars are being used in a productive and/or beneficial manner. I need to convince the politicians not to defund the NSF, because I need that money to do my research. I need to convince the public that my work is crucial, vital even, so that they might complain loudly when a politician decides that they want to cut funding to the NSF.", "Beyond what people are writing about the huge investment these things take, the truth is often that these \"discoveries\" are nonsense. For example, often you will hear a story about a \"miracle cure\" for such and such. But if you look deeper, the story is reporting on a lab experiment testing the drug in cells in vitro which may have a novel or promising mechanism of action...but that's a far cry from repeating its success in other studies, much less animals and much less demonstrating effectiveness in treating human diseases. While that does take years and some of these drugs are ultimately successful, the vast majority are abandoned down the pipeline because they aren't as effective as was hoped. You see another version of this with claims about \"new drug treats so and so with virtually no side effects.\" That may be true in clinical trials when its given to a limited number of people...but once the drug hits the market, who gets it? Many many more people. Elderly. Children. Pregnant women. People of various ethnicities, not to mention just many more people with varying genetics. Everything has side effects and some of them are pretty darned serious. You'll see articles about cures for cancer that are developed. But the stories are misleading because they are really talking about preliminary success in developing a new strategy to target one specific type of cancer. Even if it passes muster throughout its years of development its impact is going to be pretty limited. You'll probably never know of its usage unless you or someone you know eventually comes down with that specific disease. For example, researchers in Glasgow and Hong Kong last year discovered that injecting a protein into mice brains could reduce amyloid plaques. That's important work. It's all well and good. But doctors aren't sure that amyloid plaques cause Alzheimer's or are just another symptom of the disease. In the unlikely event we find a way to increase the expression of this protein in human brains and in the unlikely event it removes 100% of amyloid plaques, it might turn out to have 0% effect on curing Alzheimer's...and it will be years before we find that out. These stories are amazing because the media wants you to read their website so they publish interesting yet mundane stories in an overly sensational way. EDIT: I did not mean the discoveries themselves were nonsense. I meant the media is overdrawing the conclusions of preliminary evidence to nonsensical levels. Should have phrased more carefully.", "It depends. Sometimes the stories are misleading, say for instance they've made a small breakthrough but the research still needs more time and/or human trials, but the story published makes it sound like it's available on the market right now. Sometimes it's just a grab to get people to a site and it's a whole lot of rubbish.", "Pharmacist-in-training here. At least in the field of medicine, all new methods of treatment must be \"evidence based\" meaning someone has to take that new thing and compare it to the one currently available. As an example, comparing the how well the $5 epipen works against a typical $30 one. For this reply, let's ASSUME the $5 epipen actually works and isn't a sham. This process is called a \"Clinical Trial\" and often costs millions of dollars because you need to recruit hundreds, if not thousands, of people to use your $5 epipen or the $30 epipen and check back for results and such. This often requires hundreds of staff members, facilities, tools, and even the pens themselves, and if I'm not wrong, not many high-school students or even adults have millions of dollars they can invest into this process. It's the same for the new omega antibiotic, cure for cancer, or protein to cure Alzheimer's Disease. Regardless of whether it works or not, in order for it to be regularly used, it takes years of work and lots of money, which is why these \"amazing discoveries\" are rarely followed-up.", "When I was a 'journo' I'd use sources like URL_1 to find nice stories that I could rewrite so they were unique and then promote them on social media sites. Eurekalert is already Buzzfeedy in its headlines, and you can tell when you read a little deeper into the article that the research was not as groundbreaking as the headline makes it appear. It might be a mouse model, it might be just a survey of 2000 people, it might be a study involving 20 people. Then when I wrote it up, I would purposefully try to avoid anything that highlighted how meaningless the study was, and I'd try to write something even more Buzzfeedy than the actual article. AIDS cure 'around the corner', 'Study: AIDS can be cured by bananas'. If I put some of the headline in 'snatch quotes', i.e. apostrophes, or put a colon indicating that someone had said something, i.e. 'Cameron: Fuck Daesh', then I would have covered my ass from misrepresenting the topic, provided I didn't totally misrepresent it. And I was churning out 5,000 words a day, often researching and spinning a 200-word article in 20 minutes. I would honestly just skimread the original source, I'd only actually read it to fully understand it if I was personally interested in the research. Furthermore, my understanding of complicated science is nowhere near good enough to be able to criticise a scientific study, all I'd do is 'spin' it. Churnalism, it's called. Shockingly, one of my skills is being able to push things to the top of Google search results. Quite often, when writing something more meaty, my research would be reading whatever was at the top of Google search results, which I know full well is written by someone who's just as big a moron as me and who's just as pressed for time as me. tldr, the internet is a tapestry of bullshit. .... Here's an example, in fact if I was spending 20 minutes on 200 words I would've spent 5 of them on Facebook. URL_0 See it's all full of confusing stuff but I might think 'this is the kind of thing people will read'. This doesn't comply with all the rules of news writing but it's pretty close: Could e-cigarette users face a higher cancer risk than smokers? Alternatives to tobacco, such as e-cigarettes, have become increasingly popular in recent years, and are much-touted for their health benefits. However, a new study, which found that smokeless tobacco users have higher levels of carcinogens than smokers, could end any claims that alternatives to cigarettes are better for you than cigarettes themselves. The research, which was published in Cancer Epidemiology, Biomarkers & Prevention, a journal of the American Association for Cancer Research, found people who use smokeless tobacco have higher levels of tobacco constituents cotinine, NNAL and other deadly toxins than people who exclusively smoked cigarettes. Brian Rostron, PhD, an epidemiologist in the Center for Tobacco Products at the U.S. Food and Drug Administration, said that these biomarkers show that smokeless tobacco users face \"adverse health effects, including cancer\". \"Our findings demonstrate the need for continuing study of the toxic constituents of smokeless tobacco as well as their health effects on the individuals who use them,\" he added. As well as e-cigarettes, other popular nicotine-replacement devices include snus, snuff and chewing tobacco. PS it's all bullshit man, the study's about smokeless tobacco products, and I strongly assume that this means snuff and snus and chewing tobacco and that ecigs don't even count. But nobody's gonna sue me and it's the kinda thing people would share. > This is a repost of my most popular post ever! From: URL_2", "There is huge amounts of misreporting in the media of scientific results. Media outlets are interested in sensation and views - actual medical research is incredibly dense, technical and therefore boring to many people. For example, you often hear about cures for cancer. The problem is that cancers are incredibly complex with a vast variety among them. There maybe thousands of tiny molecules, each with a name and chemical formula, that researchers are studying. The 'breakthrough' may be showing that one of those compounds is elevated in x disease. What actually needs to occur for a real life change? They need to then figure out the causal relationships - I.e. Is the compound elevated as a cause of the disease? Or is it as a result of the disease? If we lower it, does the disease get better? Or is it useful as a marker of disease? If so, how can we measure it in people? Can we use a medicine to improve it? Once there's finally a possible therapy, it's tested in animals and people and that takes forever. You also often hear about the successes but not the scientific failures (there are more failures than successes). Other researchers then painstakingly research other compounds, using different methodologies, all in hope of very very slowly piecing together a coherent picture in order to achieve therapy. So basically, medical and scientific research more generally, is akin to carving away a wall with a spoon.", "In 99% of the cases, it's bullshit. News organizations love to exaggerate scientific findings or experiments because they get a lot of views - like getting first page on Reddit. This is extremely common in \"scientific news\", not only in medicine. Preliminar studies, meant to show an idea is worth of extra funding for more conclusive tests, gets overblown as a decisive result. HIV gets killed by this drug in petri dishes? \"SCIENTISTS FIND CURE FOR AIDS!\". Pesky details that get in the way are ignored. A better treatment for one cancer was found? \"SCIENTISTS CURE CANCER\". Treatments in the very first steps of development are reported as certain and ready, when in fact most of them will be discarded while being developed or accepted for one or more of several reasons. Initial testing shows a discrete improvement in Alzheimer patients? \"CURE FOR ALZHEIMER IN THE WORKS\". Most people stop at the headline, some get to the article, almost no one goes to the paper, so it gets shared, viewed and upvoted. Just check /r/Futurology to see how effective this is. And since most of new developments in these areas fail to reach the market, these solutions simply disappear.", "> \u201cBriefly stated, the **Gell-Mann Amnesia** effect is as follows. You open the newspaper to an article on some subject you know well. In Murray's case, physics. In mine, show business. You read the article and see the journalist has absolutely no understanding of either the facts or the issues. Often, the article is so wrong it actually presents the story backward\u2014reversing cause and effect. I call these the \"wet streets cause rain\" stories. Paper's full of them. > In any case, you read with exasperation or amusement the multiple errors in a story, and then turn the page to national or international affairs, and read as if the rest of the newspaper was somehow more accurate about Palestine than the baloney you just read. You turn the page, and forget what you know.\u201d", "Most articles from a pop news site are often written by scientifically illiterate journalists, or journalists who don't know that much about the field and rewarded for reporting something that sounds exciting. This [comic]( URL_0 ) sums it up. Also, preliminary findings in animals or in vitro get touted as promising. We've cured millions of mice with various treatments that don't translate into humans. Last there is a publication bias, meaning I am more likely to publish an interesting finding. Let's say 100 people flip a coin 10 times. One guy gets heads all ten times. It was chance, but he doesn't know that, since he doesn't know about the other people. He submits his paper showing how coin flips always end up heads, and the journal publishes this. Then later, someone else repeats the study (hopefully) and it turns out that the initial finding was random chance.", "My girlfriend does pharmaceutical development, she takes things like this and tries to convert it to a tablet or however else you are supposed to use it. It is a super complicated process to do this, and at some points in development you basically take what you think is the proper way to package these drugs and place it on a shelf for a few years to see how it breaks down and how it is coated. Doesn't always work out and you have to try again and play the waiting game, which means you start over and have to wait. We have been together for almost three years and drugs that she was developing when we met are still doing the shelf waiting game.", "I work in scientific research. My job is to take research and get investment from industry to move the science into a commercial outcome. I see a lot of ideas here that represent the 'next big thing', but is really just a very early stage idea. When I point this out to people I get downvoted to oblivion. So basically what happens on reddit is that people love the idea and pile on with the upvotes, even when the idea has little merit. So from a reader perspective, the concept looks like the greatest thing ever, but its just really just vapourware.", "TL;DR Media talks shit. Rarely understands what they're reporting on and generally misleads the public. Most advances take years to decades to go from concept to in production.", "Survival rates for a lot of diseases are up compared with 10 years ago. We have super-computers that fit in our pockets. We have cars that drive themselves and run on batteries. The future doesn't arrives in big jumps, but it arrives on non-impressive small steps. It is so slow that you get used to most incredible and amazing technologies without realizing it. Medicine is not different from the rest. Keep investing in education and research, wait for it. :D", "They don't happen in the first place. In the vast majority of cases those headlines are massively overstated. A new anti-cancer drug gets the go-ahead for a small round of human trials and /r/science reports it as 'NEW CANCER-MELTING WONDER-DRUG APPROVED FOR HUMAN USE'. SpaceX announces a new booster rocket design and /r/space cries that 'ELON MUSK IS TAKING US TO MARS THIS YEAR IN A LUXURIOUS USS-ENTERPRISE-LIKE SPACECRAFT'. The new version of Android has slightly fewer bugs and security flaws than the previous one and /r/technology decides that 'NEW SMARTPHONE SOFTWARE ELIMINIATES YOUR NEED TO EAT SLEEP OR PEE'. If you actually read the articles, you would realise that this is nearly always the case.", "Same as all the global warming articles about how there will be no more ice by 2015, the world is doomed, global warming is \"even worse than we first thought\" repeated each week. Fake news to make scientists money", "From what I've learned it is often a 3 step process. Invention = making a new discovery or creating a new product. For example, someone creates a flat glass touchscreen. Innovation = taking an existing product or invention and making improvements to make it more user friendly or applying the invention to an actual problem. Example, I found a way to put the glass touch screen on a phone. Entrepreneurship = Creating a business that meet a demand by selling a product in a profitable way. Example, you start selling the first iPhone. These steps can all be done by the same company or individual, or sometimes each is a separate entity. You could invent something incredible, but it is lacking in usability, or maybe this inventor even has an innovative product which meets a need, but lacks the business acumen to turn it into marketable product.", "Because either there were scam artists or there was a fundamental issue exposed on the path to commercialisation. You have ideas, theory and lab results on one hand, and real world practicality and profitability on the other.", "u/toastshop posted this about a year ago in a very similar eli5 thread. I think it's something every person in the world needs to read at least once. When I was a 'journo' I'd use sources like URL_0 to find nice stories that I could rewrite so they were unique and then promote them on social media sites. Eurekalert is already Buzzfeedy in its headlines, and you can tell when you read a little deeper into the article that the research was not as groundbreaking as the headline makes it appear. It might be a mouse model, it might be just a survey of 2000 people, it might be a study involving 20 people. Then when I wrote it up, I would purposefully try to avoid anything that highlighted how meaningless the study was, and I'd try to write something even more Buzzfeedy than the actual article. AIDS cure 'around the corner', 'Study: AIDS can be cured by bananas'. If I put some of the headline in 'snatch quotes', i.e. apostrophes, or put a colon indicating that someone had said something, i.e. 'Cameron: Fuck Daesh', then I would have covered my ass from misrepresenting the topic, provided I didn't totally misrepresent it. And I was churning out 5,000 words a day, often researching and spinning a 200-word article in 20 minutes. I would honestly just skimread the original source, I'd only actually read it to fully understand it if I was personally interested in the research. Furthermore, my understanding of complicated science is nowhere near good enough to be able to criticise a scientific study, all I'd do is 'spin' it. Churnalism, it's called. Shockingly, one of my skills is being able to push things to the top of Google search results. Quite often, when writing something more meaty, my research would be reading whatever was at the top of Google search results, which I know full well is written by someone who's just as big a moron as me and who's just as pressed for time as me. tldr, the internet is a tapestry of bullshit.", "Just remember that when they announce a discovery, they then have to be approved for and perform human trials which may take 5-20 years. Also, the $10 \"EPI\" pen was just released.", "With more promising breakthroughs, what happens at times is a problem is discovered in the next step or 2 and it's then halted and sweapt under the rug, or back to the drawing board. Then we hear about it again.", "I do product development and formerly have been a scientist and entrepreneur. Let me sum up. Media typically overstates scientific discoveries. This is because science is nuanced but media usually isn't, since most stuff is written for a 7th grade reading level or below. Media has to sell ads to survive so they keep it accessible. A discovery in the lab is one part of building a product you can sell, but there's a lot more to it. Many things can go wrong in between a discovery and trying to create a successful product and business to support it.", "Testing. When they say they have found a cure for cancer they mean in a select few test subjects under certain lab conditions. Doing the real tests to make sure its safe for everybody can take years and may or may not be successful. As for the $5 epipen you can take a look at projects on kickstarter that have failed. There are people who've made really cool stuff for a reasonable price but, when they suddenly have 100,000 pre orders they find that to actually fulfil that many orders costs a lot more than they originally asked for. So whilst this kid created an epipen for $5, to actually produce it on an industrial scale could push the price up a lot further. That being said there is a $10 epipen available now.", "It's simply sensational news, Reddit's forte. The same trend can be seen in politics - every word out of a loved politicians mouth is praised and every word out of a hated politician is twisted and exaggerated. The same thing can be seen with terrorists who kill < 20 Americans worldwide a year. You'd think 50 people were dying over here a day as much as it's talked about. Spend 1/1000th of the effort that we spend on terrorism on something like cigarettes, obesity, opioid and save more lives. So it's not about lives... wtf is it about? It's about the media and about $. CNN and Reddit and every other news organization is rewarded with views (ad revenue) for every sensational story that's run. It's the same reason a \"cure for cancer\" shoots to the top of Reddit even though some of them can be considered \"fake news\". The scary party is I'm not sure if there's a solution unless it comes from within society.. which ain't happening.", "For the examples you gave, there are brutal regulatory hurdles. Governments don't want people selling \"a cure for cancer\" without evidence that the treatment actually cures cancer. To demonstrate that you need to conduct pretty extensive clinical trials - which themselves are highly regulated. That's because governments don't want people to administer drugs where the effects and side effects aren't known - except in tightly controlled circumstances. This process can take many many years. In addition to this, the path to commercialization isn't easy - and that holds true for almost every invention. Going from \"proof of concept\" to prototype is generally all hand crafted one-offs. The commercial model needs to be developed such that it can be produced in mass quantities, and preferably at low cost. Figuring this part out is hard, expensive and high risk - and usually the people who are great at inventing or discovering stuff aren't great at scaling up, supply chain, and logistics. It requires distinctly different skill sets and attitudes. This part of the product development cycle is sometimes referred to as \"The Valley of Death\" because so many inventions and discoveries do not make it past this point.", "I worked in a University laboratory for 3 years. We were funded by NIH. We had defined goals that we would meet in x amount of time. On our way to meeting our defined goals we produced \"new\" techniques and information, yet to be seen in our lifetime. If journalists or people that were generally interested in our research, understood (scientifically), what we were doing they can write about and extrapolate on our findings. Often, scientist (legit scientist, not some Boflex commercial people) ONLY publish their results in research journals, accredited/validated sources of information. Not to say journalists or PROMISING stories are false but it is people, with a science background, making claims that are possible but unjustified. Its like stem cell research, is it legit, WELL DUH, but depending what protein or genetic aspect you are studying. Scientists dedicate their lives to studying one protein or one organism and define as much as they can about it. It is easy to say something can or will do this, but in reality it is an extrapolation of possibility. Basically, you can and will read an article that says \"Cancer has been cured\" but this is not in Nature the science journal. It is someone with a science background jumping to inconclusive conclusions. Articles that state miracles extrapolate, and make the grunt of science look great. While beneficial to fund and continue research they are not accurate nor truthful.", "Speaking of the Epipen, pharmaceutical prices in the US are basically arbitrary in regards to pricing a specific product. There's no reason an Epipen should cost $600, and widgetpill costs $6, They could just as well be reversed. Someone in a suit just entered numbers in a computer and decided that's what the price would be. The reason for that is so much of the cost of drugs has no relation to the actual drug. You can sell the drug for slightly more than the cost of production in Togo, but you need to make up the costs somehow. And that burden falls to consumers in the US because our insurance company can pay for it (and if there's no insurance there's normally discount programs so we pay something more like someone in Togo. Not a lot of uninsured people are paying cash at the point of sale full price for Epipens, those that are our obviously squawking about it so we hear about it.) So why do drugs cost so much?, yes, unlike most hospitals and some insurance companies pharmaceutical companies are for-profit, but developing a drug is unfathomably expensive ($2.5 Billion), and America is so litigious that ads seeking to sue pharmaceutical companies are a television staple. So what about the $5 epipen. It's easy to 3D print something and say you can manufacture it for \"X\". But to get it approved for sale, buy insurance for when you get sued by someone saying it made her ears turn purple, it's probably going to be well north of $100. Still cheaper than the alternative, but no bank is going to upfront money to pay for studies and tooling when the Epipen makers could just lower their price to $95 in response to competition on that product (and raise price of widgetpill to $600 to compensate).", "As a scientist, I cannot tell you how maddening it is to read (most of) those articles. News articles like that are almost always written by people with no formal education on the topic they speak of, and I dare say little informal training. They sensationalize findings, because they are more concerned with how many people read their story than how well they are representing the actual facts. Usually the researchers themselves include a discussion that puts their findings into context, but you have to read more than simply the abstract to get to that. News reporters misrepresent the relevance/strength of findings to the point of fiction. I've seen it countless times. Or worse - they report on things as \"scientific breakthroughs\" that haven't even been vetted by peer review. I saw an excerpt on the news recently about a professor who was able to power his house with a glass of water thanks to a new highly efficient device that creates energy using water as fuel - something that can be done but not anywhere close to the remarkable efficiency of his. They waited until the very end of the segment to mention that the professor is holding off on submitting his findings for peer review until he gets a \"worldwide patent.\" The same can be said for that Italian neurosurgeon who was supposedly doing head transplants. A single study only carries as much weight as the strength of its methods, especially regarding the sample size. Findings must be taken into context of the larger body of research already existing. It is not particularly uncommon for a small study to conflict with the actual truth - and by \"truth\" I'm referring to the collective pool of data from all well-run studies on the topic. This is because of statistics, and something called confidence intervals which I won't get into here but if you're interested I'll expand upon. Yet, very rarely do organizations such as the American Heart Association, who compile multiple studies and come out with only strongly supported findings, report anything that is (to a general audience) striking or newsworthy. You don't see the Cochrane Library upturning well-established facts with new and sensational studies every week. Because that's just not how science really works, with very few exceptions."], "text_urls": [[], [], [], [], ["http://www.eurekalert.org/pub_releases/2015-11/aafc-hnc111615.php", "http://www.eurekalert.org/", "https://www.reddit.com/r/explainlikeimfive/comments/3tb9gl/eli5_why_nearly_everyday_is_there_a_post_on_the/"], [], [], [], ["http://www.phdcomics.com/comics/archive.php?comicid=1174"], [], [], [], [], [], [], [], [], ["http://www.eurekalert.org/"], [], [], [], [], [], [], [], [], []], "score": [5097, 2417, 1773, 384, 141, 129, 62, 35, 26, 15, 14, 12, 12, 9, 6, 6, 5, 4, 3, 3, 3, 3, 3, 3, 3, 3, 3]}}, {"q_id": "5t5j6k", "category": "Repost", "title": "How does a turning a faucet change the temperature of water", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddkbkr2"], "text": ["There are two tubes running into your faucet. One straight from the mains, and the other from your water heater. When you open the faucet, the tap itself opens to allow water to flow out. When you turn the faucet, you are changing the amount of water coming through each of the pipes. All the way to the hot side opens only the hot water pipe and not the cold one. Same for the cold water side. In the middle should ideally be half and half, but since the water heater heats the water to uncomfortable temperatures, the middle generally allows more cold water so you don't burn yourself."], "text_urls": [[]], "score": [5]}}, {"q_id": "5t8hbl", "category": "Repost", "title": "What happens when you download something?", "title_urls": {"url": []}, "selftext": "How does data get from one computer to mine, and what happens if I pause/cancel it half way?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddkwqkx"], "text": ["The data is a file. There are other explanations for how the Internet works if you search. The file exists somewhere as a complete file. It can be a photograph, music, speech, a video, some program you can run, anything which is data. Your download command is a request that the file be sent to you. Sometimes these files exist in multiple locations, called mirrors. The responding computer, or server, a specialized computer for moving information, starts transmitting this file to your computer breaking the data up into little bits called packets. Each packet has your computer's address built in and enough information that your computer can reassemble the data perfectly. This includes tricks used for error checking. If packets get lost or scrambled there are routines for retransmitting them. The file was only copied. It is not destroyed at the source. Your computer receives all the packets and reassembles the file. In the file there is a description of what it is and what to do with it. If it is a photograph there are instructions as to how big it is. If it is music there is a description of how the file was coded. Your computer will process this file according to the instructions. It will show you a video, play a song, or run a program. Some of the programs are viruses which can harm your operating system."], "text_urls": [[]], "score": [9]}}, {"q_id": "5ta4xl", "category": "Repost", "title": "Why do men become bald-headed more often than women?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddlbaio"], "text": ["Testosterone, while it is responsible for secondary sex characteristics such as body hair growth and the deepening of the voice, is also toxic to hair follicles on the top of the head based on its reaction with some of their androgen receptors. Based on genetics and cell type, different parts of the body respond to testosterone differently."], "text_urls": [[]], "score": [16]}}, {"q_id": "5thihs", "category": "Repost", "title": "What actually happened with the Y2K bug and exactly how was it resolved?", "title_urls": {"url": []}, "selftext": "I was alive then but too young to recall any of it but I hear about what a big deal it was quite often.", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddmiyiu"], "text": ["Okay. So a lot of early computers kept track of the date with just the last two digits. This let them save space and time programming, back when every little bit of information mattered. This meant that for many old computers, going from 99 to 00 would make it seem like everything was now in the past, that new files would be made that happened before the existing ones. This had the potential to really mess up a lot of systems. So a concentrated effort by computer programmers around the world was made to ensure that this wouldn't happen. They found old computer code that used just the last two digits and expanded them so that you wouldn't have problems when it became the year 2000. It could have been a serious problem, but we managed to pretty much keep it all under control."], "text_urls": [[]], "score": [11]}}, {"q_id": "5tkz8g", "category": "Repost", "title": "why (some) Americans hate Obamacare?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddndckg", "ddna4nz", "ddnbobf", "ddna60j"], "text": ["1.) It fundamentally changed the relationship between the federal government and the individual citizen. This was discussed at length during the Supreme Court hearing (by Kennedy, I believe), pointing out that the government had never claimed the power to force individuals into engaging in commerce with other private parties under penalty of law. 2.) It was a windfall for the very insurance industry that was villainized during its passage. You would be hard-pressed to think of a better way to enrich the Insurance companies while doing very little to address the underlying issues with the cost of healthcare. 3.) It is detrimental to a significant portion of young working families by either forcing them to buy insurance at a time when it is reasonable to forego it due to low risks or to buy it at higher premiums. 4.) The law was huge and complicated, but passed in a rushed, opaque manner at a time when the Democrats had a near supermajority in Congress. It really felt like they were trying to slip something by before anyone had a chance to fully analyze it, leading to a very difficult implementation. The law was rapidly written in a piecemeal fashion by multiple parties, leading to contradictory language and badly in need of a streamlined approach. 5.) It failed to remove long-standing and important barriers to insurance access such as the an on interstate purchase of insurance. This a particularly egregious example of congressional overreach based on the Commerce clause of the Constitution. Congress simultaneously bans interstate commerce on insurance and claims the right to regulate it as interstate commerce. 6.) It is the worst of all solutions. It is neither the relatively simplified and easily regulated single payer solution nor the fully competitive free market solution (I.e. removing barriers like in number 5), but with arguably some of the worst elements of both. I could g on, but I hope this at least shows that it's not all partisan vitriol spewed by puppets of the almighty Fox News clown show as some claim.", "Middle-class hates it. For the lower class it really is helpful and useful, but if you make a normal amount of money it is expensive as FUCK to pay for", "I could be mistaken, but I could have sworn before it came into effect, Obama promised that it wouldn't cause my current insurance costs to go up. They went up a fucking lot.", "The government forces people to buy a certain product or be penalized, which is illegal and stupid. Obamacare made everyone's health insurance cost go up by a huge amount (my wife's increased by 400%). Also, it's immoral for someone to steal my money at gunpoint to pay for someone else's medical care."], "text_urls": [[], [], [], []], "score": [11, 8, 6, 6]}}, {"q_id": "5tl0mb", "category": "Repost", "title": "Why is it that when we are enjoying ourselves that time seems to go by quicker?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddnauo9", "ddndox6", "ddngw8l"], "text": ["I think one of the main reasons is we get lost in what we are doing and don't think about the time passing, but when you're going through something you don't like you are constantly thinking about the time and looking at the clock", "There's something called \"flow\". It's a mental state created by doing something that matches your skill level, and is enjoyable, but also slightly challenging. Flow is like when you're extremely focused on your task and the world kind of disappears.", "A cool book just came out called \"Why Time Flies\" and what I have read of it was really cool!"], "text_urls": [[], [], []], "score": [29, 12, 3]}}, {"q_id": "5tlo9g", "category": "Repost", "title": "How come our TV never buffers like videos on our phone or computer does?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddne61l"], "text": ["Your TV has an input source dedicated to just providing the video stream. It is never interrupted with other traffic. Internet streams are split up into small chunks called packets, which are sent through many different routing devices to get from the server to your computer. Each of those devices has a maximum speed, and if one if them gets overloaded with a spike in traffic then some of that traffic will have to wait. To try and avoid random pausing in the video your receiving device will 'buffer' a few seconds of the video. That is it has for example the next 10 seconds already downloaded and ready to play. If the download is stopped for a second it will keep playing through the 'buffered' 10 seconds, and keep downloading as it can. It will also try to download a bit faster to increase the size of the buffer. Satellite TV doesn't do this because the satellite is broadcasting a dedicated stream directly to your receiver. There are no intermediary devices, and no other traffic to get in the way."], "text_urls": [[]], "score": [3]}}, {"q_id": "5tm0sd", "category": "Repost", "title": "who decided we needed different timezones? Why couldn't 1AM be the afternoon in parts of the world?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddngcif", "ddnge3p"], "text": ["Because that would be inconvenient, especially if you travel between time zones often enough. It would be frustrating to check the time and see that it's 1pm and think it's lunch time, only to realize that the sun is setting and you have to go to bed in order to be up for work. Noon was designated to be the time when the sun was at its highest point, so 1 pm is one hour past that time. It's been like that for thousands of years, ever since timekeeping became a thing. Consider this: Right now, if a business lies across time zones, it can still have consistent times that it's open. For example, it could be open 7am to 2pm. And this would be basically the same time of the day across the country. However, if there were no \"time zones\", then each area would have to have its own opening hours set in order to be open around the same time of day as the other locations (let's say it's a breakfast and lunch-type diner) and so you wouldn't be able to advertise \"Open at 7am every morning!\" across the country, but would have to make separate advertisements for every single area your business is in with their own hours (\"Open at 1am every morning!\"). Also consider: It's 4pm where you are. With time zones, you can check what time it is in Australia, and see that it would be an inappropriate time to call there. However, if you didn't have time zones, you would have no way of knowing unless you looked up some kind of additional chart to see what part of the day that would be.", "Before timezones everyone set time locally. Noon was when the sun was directly overhead and all other hours were set accordingly. Timezones formed because of trains and the need to have more accurate and consistent timekeeping for the arrival and departure of the trains. The timezones were designed so that noon stayed roughly overhead at mid-day in each timezone as to not disrupt work schedules and life. The suffix pm means \"post-meridiem\" meaning after midday. The suffix am means \"ante-meridiem\" meaning before midday. AM times cannot be in the afternoon because that is \"AFTER NOON\"."], "text_urls": [[], []], "score": [16, 6]}}, {"q_id": "5tmh19", "category": "Repost", "title": "Why do we not remember the last moments before we fall asleep?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddnjmzb"], "text": ["One aspect is that the information isn't that important and you're not receiving much information into the brain, so what is there to remember? It's also important to realise that 'sleep' and 'wakefulness' are really just two points on an entire spectrum of consciousness. It isn't like you instantly go from being awake to being asleep; your brain slowly begins to inhibit lots of different parts of itself and the body. Your muscles become more paralysed, incoming information is filtered out, and eventually many of your brain processes (including memory) are inhibited."], "text_urls": [[]], "score": [9]}}, {"q_id": "5tmzwk", "category": "Repost", "title": "Why is it so hard to produce a good consumer printer?", "title_urls": {"url": []}, "selftext": "I understand, that requirements for printers are vastly different in the enterprise, small business and private sector. But it can't be that hard to produce and easy to maintain and reliable device, can it? Most of the time when I print at home either the colors are off because one of the cartridges gives up or my OS takes ages to get a connection to the printer. So: Why is it so hard to produce a good consumer printer?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddnmo93"], "text": ["It's not. It's hard to produce a great quality consumer printer _at a price that people are willing to pay_. Long ago printer manufacturers discovered that they could make more money by offering dirt cheap printers (I saw one on sale recently for $10!) and charging exorbitant prices for the ink. I'm sure there's some consumer psychology at work here, i.e. people will want to pay less up front even if it means they pay more over time for the supporting consumables (ink) than pay a lot up front in exchange for cheaper consumables down the road. There's some sense to that since the consumables are a less predictable cost."], "text_urls": [[]], "score": [5]}}, {"q_id": "5toche", "category": "Repost", "title": "What happens when you are driving from a country that drives on the left side to a country that drives on the right side?", "title_urls": {"url": []}, "selftext": "i.e. Thailand to Cambodia or vice versa.", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddnukg6"], "text": ["They make you stop at the border and cross sides, and lots of warning signs remind you about it. [example]( URL_0 ) In a *very few* cases, a special cross-over ramp is built so you can change sides without stopping, but that's expensive. [example]( URL_1 )"], "text_urls": [["http://iloapp.postkortsamling.com/data/_gallery/public/32/1253944666_resized.jpg", "http://images.fastcompany.com/upload/Dia15____JPG_800x600_q85.jpg"]], "score": [15]}}, {"q_id": "5tq0p7", "category": "Repost", "title": "Why does your chest actually hurt during emotional distress?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddoeuzh"], "text": ["One line of thinking postulates that there are two components to physical pain - affective and sensory. The affective component is strongly associated with a part of the brain called the dorsal anterior cingulate cortex (dACC; note there is no exact 1:1 mapping, just a strong correlation). It has been found that the dACC is also highly active during emotionally, but NOT physically painful events, such as financial hardship. The idea is that, because pain is such a useful tool to have in terms of adaptive fitness, the dACC has been \"coopted\" to activate during purely emotionally painful events, and the feeling is subjectively similar. See a paper called \"Broken hearts and broken bones: a neural perspective on the similarities between social and physical pain\" (Eisenberger, 2012) for a more complete overview."], "text_urls": [[]], "score": [16]}}, {"q_id": "5tq1le", "category": "Repost", "title": "Why is it that, when you are congested, one nostril is a mucky swamp and one is dry as a bone but then they pull at fast one on you and switch??", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddo9hyl", "ddo9fpj", "ddoenbf", "ddo9msd", "ddoekkr", "ddoi495", "ddoixtq", "ddof9va", "ddogvxq", "ddoj6w3"], "text": ["You don't notice it when you're not sick, but your nostril actually do this all the time. It's just exaggerated when you're sick. It's called the nasal cycle. At any given time, one of your nostrils is doing most of the work and is clear, while the other one is \"resting\" and is more congested. It's managed by your autonomic nervous system so you can't control it and most of the time don't notice it. There are two reasons for this. The first is that it gives the cilia and mucous membranes a chance to rest so they can better filter and humidify when they're doing the work. The second is that it helps you smell better. Some smells are better detected in fast-moving air, and some are better detected in slow moving air.", "Most people have a so called \"nasal cycle\" where the amount of air going through each nostril fluctuates. At any given time even without a cold if you put your hand under your nose, you may be able to feel that more air is coming out of one side than the other. This helps us smell better by giving each nostril a break once in a while. So when you are congested the nasal cycle continues and the side that is getting more air flow will be less stuffed up than the side that is taking a break.", "What happens if you don't have a nasal cycle? I had multiple sinus surgeries as a child by a not so great ENT (literally cauterized my sinuses with too little local anesthetic) and I don't experience this. If I'm lying down, congestion will switch sides if I change position, but only then. I also have a terrible sense of smell.", "Not sure about the congested part (because personal experience is different), but generally one of your nostrils is always (partly) blocked while the other does the breathing, and they switch periodically. One hypothesis is that this forces a human to change sides when sleeping, [which prevents stalling of circulation in the body parts under pressure]( URL_0 ). Source: Wikipedia.", "There's a very good episode of SciShow that discusses exactly this topic: URL_0", "I believe all the other commentors are correct, but let me say that it feels amazing being able to breath through two nostrils for a minute or two when you're *that* sick.", "I like when it makes a small click sound and suddenly that nostril is open to breath freely. I've noticed this since I was a little kid.", "After having a ER room visit (temp spiked at 104.8) level of the flu for the past 7 days, I was also wondering this as I rarely get sick and never dealt with a stuffy nose that randomly selected the side it was going to piss me off with before. Thanks OP for asking, this honestly helped.", "Why does it flip when i change sides in bed? Also what does nasal spray do?", "This is why I love ELI5. It answers questions I think about when I'm sick but forget about the rest of the time."], "text_urls": [[], [], [], ["https://www.reddit.com/r/askscience/comments/1urizz/why_do_we_change_positions_during_sleep/"], ["https://youtu.be/BGACvb3Mm60"], [], [], [], [], []], "score": [833, 38, 16, 12, 8, 8, 6, 6, 4, 3]}}, {"q_id": "5tqah0", "category": "Repost", "title": "What do people on Wall street actually do?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddo9450", "ddo8v36", "ddo9b4n", "ddoc7l8", "ddog6ia", "ddoc6eq", "ddoat9q", "ddon7ww", "ddob0co", "ddofmoq", "ddodbjr", "ddofw48", "ddof507", "ddoeee1", "ddom4cj", "ddof0uk", "ddoer7z", "ddog04u", "ddolbai", "ddom3qu", "ddoaz69", "ddoh50p", "ddoih7d", "ddofz0s", "ddoesay", "ddoj00p", "ddohwro", "ddogeyx", "ddol021"], "text": ["Let's say you want to make widgets, but you need money. You could ask out investors, but if every inventor had to talk to every investor it would be time consuming. So investors give their money to fund managers and the fund managers distribute the money to inventors (taking a cut off the profits from investments or charging or fees). Everything else is just increasingly more complicated ways of trading risk for money. It's not much different than a grocery store. If every person that needed did had to contact and trade with every farmer it'd be insane. The grocer doesn't make anything, but they take a cut for facilitating a trade (essentially).", "on a very simple level - they move around money. and they move this money between things which are all the time changing in value. so if $100 is moved over into the form of a share in a company, the next day (or the next minute..) that money could now be worth something else. given the size of wall st, we are talking about the movement of hundreds of millions of dollars. and when an investment goes badly and $100 million becomes $50 million, or vice versa, and when this happens all the time with BILLIONS of dollars - it effects the economy. So what purpose does it serve society..? Not too much really... but what effect does it have? HUGE Edit: i have received some flack for my last line saying Wall St does not do much to serve society. What I meant by this is to be neutral - Wall St certainly has its benefits, but was also the cause of the global financial crisis in 2008. But I think its effects are more interesting to discuss then what purpose it serves society. Edit 2: I am receiving more and more aggressive messages about how wrong my post is, followed by long complicated answers which simply expand on exactly what I said - Wall St moves money around. And by moving it around, it causes ripple effects across the economy. I apologise for not being able to explain the ins and outs of Wall st in less than 100 words - shout out to SteelGun for his great response below Edit 3 (and final edit): HOLY CRAP REDDIT YOU'RE SO MEAN. While I am getting abused to death I still have not had ANYONE disagree with my fundamental explanation of what the people on Wall St actually do. I have however mislead people into believing that Wall St serves no purpose to society - I accept that this was written extremely poorly, and not meant to come out that way. Never have I even thought that Wall St is just a thing that's there that serves no purpose.. and you shouldn't either. I wanted to edit the post when it was on like 20 likes but only bad redditors remove things they said that people didn't agree with, so I'll leave it but yes that last line was fucking dumb. HOWEVER I have also received messages from many people backing me up and saying my answer was pretty well written for such a massive question in ELI5 terms. If you are new to this thread please read many of the long well written posts below for *other* good answers too. peace fucking lol i got gilded", "It's difficult for some people who work for a company that creates a tangible product to understand, but these financial institutes are almost always vital to a business' health at one time or another.", "When movies refer to \"Wall Street\" professions, they often refer to investment banking (like Patrick Bateman in American Psycho). In real life, Investment banks often provide transaction services and advice to companies. Their \"clients\" are companies that are looking to either buy other companies, sell their company to another company, or merge their company with another one in order to increase enterprise value (this can be referred to as M & A Advisory or just simply an investment bank). Other lesser known \"Wall Street\" jobs are in Private Equity. A private equity firm essentially raises capital from outside investors with a lot of money (high net worth individuals, family offices, pension funds, sovereign wealth funds, insurance companies) and combines that money into a \"fund\". Private equity firms leverage those funds to own stakes in other companies, infrastructure, and more in hopes of providing returns to those investors. Others, Hedge Funds, are similar to private equity firms in that they can raise and leverage massive amounts of outside capital, but hedge funds are able to invest in conventional securities like stocks, bonds, etc as well as non-conventional ones that are difficult for the \"average joe\" to understand like distressed real estate debt. Essentially, these employees are researching, analyzing, and executing and combining many strategies including buying, selling, shorting to \"hedge\" investments and seek the highest returns for themselves and their investors. Hope this helps. Source: work in finance Edit: Stakes.. not steaks - was probably hungry when I wrote this comment", "#**First lets define wall street** If by \"wall street\", you mean the general financial institutions and markets around the world including in the United States, then this is a *very* broad question. With that being said, I will give it my best shot. - ---------------------- We have three basic divisions of the financial industry. This theory on the financial industry I learned when getting both of my undergrads is not all encompassing, and obviously one could come up with other divisions that would equally describe the market. Neither description would be wrong and this will suffice. #**Financial institutions** These are (generally) the regulatory agencies that intervene in the market for various purposes. Examples include the SEC, the Federal reserve and so on. These (mostly) government institutions help regulate the market, provide various services (like issuing money), and pursue legal action against criminals. *example* The federal reserve may raise interest rates to stop or curtail inflation or it may increase reserve requirements for banks for a variety of reasons. ---------- #**Financial markets** These are the physical and virtual (ie: internet) meeting places where the various parties meet up to conduct business. In the same way you and I have a market to pick up our groceries or buy a car, markets in the financial industry are set up to reduce the cost of doing business and to allow for interested parties to conduct said business. *Example* A farmer wants to sell an options contract on the bushels of wheat he is growing for harvest. In order to meet with potential buyers, this farmer sells options contracts for a specified price on the Options market. He may do this at the Chicago Mercantile exchange, which was famous for exactly this kind of transaction. Without the Chicago Mercantile exchange it would be nearly impossible for prospective sellers and buyers of the options contracts to meet and conduct business. Another example may include a company looking to raise revenue for planned business expansion by listing shares in the company on a market (through a broker, which we will discuss below). Without being able to have buyers and sellers meet, this task is made nearly impossible, and the benefits to this transaction would not occur, namely the business would be much less likely to expand and at the same amount, and investors would have less avenues for wealth creation. ------------ #**Financial Brokers** This is a lot easier to explain. The brokers are the various clearing house associations and stock market intermediaries that facilitate these market transactions. To use the brief example I gave above about going to the store to buy groceries, if grocery stores *as a whole* are the market, then the Shop and Save company would be a broker in this analogy. ------------------- Now that we have a Very^very^very basic understanding of the background information needed to understand the financial industry, lets start answering your questions. Keep in mind, I answer these as someone with two 4 year degrees, one in Business, and the other in Economics, both with a focus on finance. > Do create anything? Simply, yes. Types of services offered include, but are not limited to the following: * Trading risk from risk averse to risk takers, like in our options contract example above * Allowing groups of people, like corporations, to raise funds, including but not limited to debt and equity issuance * Investment banks provide a wide array of services like business appraisal, Mergers and Acquisitions, and identifying market trends. * engineering complex financial instruments (usually a type of derivative) to meet some kind of goal EG: collateralized debt obligations Etc From an economic standpoint, one might distill it down to simply this saying, That the financial industry allows \"Net-Savers\" (used broadly) to lend funds to \"Net-spenders\" for a return, who then generally use the funds for some end. These transaction *generally* only occur when both parties benefit more than they lose out, and everyone is left better off. > Are they just playing with everybody's money No serious person who has studied the financial industry believes this. There are *real* socially beneficial services provided by this industry. Furthermore competition in finance is intense, and those companies and individuals that are not serious about providing value for stakeholders are ushered out or lose money quite fast. > I really have no idea Fear not, most people have no clue. In a similar fashion to medicine, or physics, Finance is a highly specialized field with professionals that often need bachelors degree or higher to break into entry level positions. There is industry specific jargon, lots of math (which the general population has issues with), and abstract concepts that take awhile to truly understand on the second level. It took me about a year of undergrad finance courses to really *truly* understand what the heck is going on in finance. I hope that helps, and if you have any questions, feel free to ask, and if I have the knowledge, I will answer to the best of my abilities.", "There's a big variety of roles in Finance. At a high level, financial institutions essentially facilitate the growth of literally every other industry there is by finding someone with money to invest in someone with a plan/project. Think small business going to a bank for a loan, but it gets scaled up and more complex with huge companies. In more detail, you have the \"sell-side\" and the \"buy-side.\" The sell-side is what you think of as Investment Banks. These are the companies like Morgan Stanley, Citi, JP Morgan, Goldman, etc. that work with institutional clients. This mainly happens through advisory and trading functions: - Advisory is what is \"Investment Banking,\" think analysts grinding away for 100 hours a week. Let's say a client retail company comes to a bank and wants to raise money/acquire a company/get sold. Let's say raise money for now, and they want to do that by selling equity (i.e. ownership stakes). First, the industry coverage group for retail learns everything about the company, and uses their expertise in this industry to put a value on the company. Once they do a lot of that, they hand it off to a market facing product group called Equity Capital Markets (the product meaning equity). This group sees what the market will accept and finishes pricing and marketing these new shares in the company. Let's say selling these shares raises $100 million. The advisory group earns a fee for doing this, as a percentage of the amount raised. - Sales and Trading. This is what you'd see in Wolf of Wall Street. Trading teams are called \"market makers.\" Someone wants to buy a stock/bond, someone wants to sell, they're in the middle. They buy the security from the seller and sell it to the buyer and a SLIGHTLY higher price and make a spread. They are out of the door at 5 PM and don't work weekends. Clients are large asset management funds (see below) and hedge funds and shit. The buy-side is actual investing. You have things like: - Mutual funds: Pretty standard funds of stocks and bonds and shit - Large asset managers: Think Blackrock. Has many mutual funds and other strategies - Alternatives: Real estate investors, private equity investors (buy a whole company, grow it for a few years, sell it for profit), and hedge funds (similar to Sales and Trading but they're the ones actually buying and selling stocks/bonds)", "Most people haven't touched upon that they help companies raise money by either issuing stock or bonds. Basically a company sometimes needs a lot of money at once to do a project or release out a new product, but they don't have that money. So in order to get that money they go to Wall Street and say \"hey I need a billion dollars to launch my new idea\". For bonds, Wall Street banks get together and say okay we have found 5 banks interested in giving you that money as long as you pay us back in 20 years and 5 percent interest. They give the company the money and the company pays them back over time. For stock it's similar but they are basically helping a company issue shares of stock for the public to invest in the company for a fix price in which the company gets the money while the investing public get potential future return from the stock in either dividends or stock appreciation. The incentive for banks to help the company issue the stock is that they get to be some of the first people who buy it.", "Hi, 15 years in an investment bank here, and I'm slightly disappointed with the top answers I'm reading, so here is my version. \"Wall Street\" is a pretty broad term and most of the big firms do a lot of things, however I'll broadly split them up as follows: **1) Corporate Banking / Advisory** **What is it?** Providing advice, lending, and all kinds of services to big companies, ranging from multi-billion dollar merger/acquisition to day-to-day payment processing **Who benefits?** This one is easy... the big companies benefit, or they wouldn't pay the fees. Every big multinational operating in different countries relies on the services the big banks provide. **Why do they get paid so much?** At the top end, the biggest transactions (e.g. the $85 billion merger between AT & T / Time Warner last year) are worth so much that the advisor's fee is like an afterthought. If you believe some good advice will get even 0.5% difference on the price paid, that's still almost half a billion dollars. Which makes a $50 million fee look like great value. **2) Sales & trading / intermediary services** **What is it?** This is probably the most complex to explain. Broadly it is buying and selling shares and other securities on behalf of other people, either private individuals or professional investors. That includes offering advice to and making purcheses on behalf of buyers (Broking), as well as advising issuers, creating derivatives, and marketing financial products on behalf of sellers (Sales). Finally there are pure intermediary services where a firm acts as \"market maker\" in other words offers to act as buyer or seller for anyone in the market to speed up the operation and avoid having to individually pair up every buyer/seller who wants to exchange their shares/securities. The market maker gets paid from the small difference (\"spread\") between buy price and the sell price. **Who benefits?** As before, many services have a direct fee that the client pays - so it is the client who benefits. In many cases the client is another bank or a professional investor. Ultimately, any company that relies on the markets for funding, or any individual who has investments or pensions, will benefit from markets operating efficiently. **Why do they get paid so much?** In a word, volume. Not many companies can provide these complex services, and the amount of money that goes through big banks' trading floors is immense, so even small percentages or spreads add up quickly. It's not just traders on phones buying and selling, there are large numbers of mathematicians, lawyers, IT people, researchers and so on making sure the services are efficient, legal, and the advice is the best available. **3) Professional Investors** **What is it?** Operating funds and making investments. This is often what people think about when the term \"casino banking\" comes up. Fund managers operate funds with other peoples money, such as pension and investment funds. Proprietary traders use a bank's own money, but they often have to try and manage the bank's own risk to ensure it has a stable overall risk profile and is less likely to fail if there is a big shock or crash. Hedge funds use a combination of their own money and other (generally large) investors to borrow money and invest it, with higher risk but higher chances for rewards too. **Who benefits?** The investors, clearly, if the fund is successful. Everyone's savings and investments are likely managed by one of these fund managers and we all rely on them doing a good job for our own prosperity and retirement prospects. **Why do they get paid so much?** They manage large amounts of money and when they get it right, they make huge sums for their investors. The rewards follow the performance of the fund and it's a cut-throat world if you fail. Overall, the answer to the question of \"who benefits\" comes down to \"money makes the world go round\". There are people with money to invest (savers, pension funds, big companies with cash reserves) and many people who want access to that money (startups, governments, major corporations wanting to invest, individual borrowers). Banks help put two and two together, in all the hugely complicated ways that a modern economy operates. Everyone who needs money, who wants to borrow or invest or even just store and move money benefits from the banks doing their job properly, in all the different ways I outlined above.", "You're going to get a lot of bias on this one, my own included. Like most jobs, there is a purpose and it can be mishandled and cause significant harm. The purpose at a high level is to create \"liquidity\". Matching good ideas/companies with money so that they can grow faster. May work best with an example. Imagine an extreme with no banks. I own a business that makes the best tacos in the world. But opening a taco stand costs a lot of money. I could work hard at other jobs, or sell tacos out of my house for a while to make the money to open my shop, but that takes a long time. Investors/loans allow me to skip the step if I can convince people my tacos are indeed the best. At a larger scale, a proven restaurant can grow much faster if they don't have to rely solely on the profits of the first restaurant to build new ones. On the other side of the bias, current wall street instruments include \"derivatives\" which basically allow someone to make more complex investments with more specific \"win\" conditions. It is arguable whether these instruments actually provide additional liquidity. Their complexity means it is easy to have unintended consequences that screw everyone over - hence the bad rap.", "Former finance bro here. The top answer is complete nonsense. Asking what is Wall St and what does it do is similar to asking what is a scientist and what does a scientist do? There are many types of scientists, and likewise, there are many posititions throughout \"Wall St\" that serve a variety of value added functions. One of the most important aspects of capitalism, at least in my country, the United States, is our free enterprise system that has taken shape in the form of the various stock exchanges - NYSE (New York Stock Exchange), NASDAQ, etc. Essentially when you see the ticker on CNBC for each respective company and a price next to it, that is the share value for a stock that means nothing except the price it costs you to buy one share of stock. A share is an ownership stake in the company being discussed. For example AAPL, is Apple which trades on the NASDAQ stock exchange and is currently valued at $132 a share. When people talk about the \"market cap\" or market capitalization, that's the value of all the outstanding shares at $132 times the total number of shares issued. This gives you the idea of the complete valuation of a company. This number is based on all cash flows and takes into consideration assets and liabilities to give you an accessible idea on the value for even the most unsophisticated investors, or workers or anyone to participate in our capitalist system. It's seriously accessible to anyone. You can buy stock for $8 a trade on some websites nowadays. So one of the most important functions of \"Wall St\" is to help companies in the process of issuing stock. When Steve Jobs and friends built Apple, they created a company and sold computers. Their individual wealth was tied into the cash flows from their ability to sell computers at a profit. In order to grow into the massive company they are today that has created technology that most of us use daily, they issued stock, which sold off shares of their company in exchange for capital. This capital is used to rapidly grow companies, and is one of the most beautiful aspects of our capitalist system. That is why any entrepreneur with a dream, creates a business, employs people, does their best to sell the best product---with the dream of eventually seeing their company they created out of their blood, sweat, and tears up on one of those stock tickers on the various exchanges. These Wall Street firms help companies grow and raise capital. That is but one function. I myself used to be a commodities trader, I worked in oil in hedging fuel prices for a major air line. We ensured stability in fuel prices which represented almost 35% of the cost structure of the company I worked for.", "Short basic explanation of how stocks work, which is a lot of what goes on at Wall Street: Imagine you have a company you own. You think your company could earn more money if you had some more cash, but you also don't want to go to the bank for a loan. Instead you cut up ownership of the company into pieces (shares) and you sell them to people interested. People will want to own a piece of your company because you say that every now and then, you will give them some a piece of the profits you earn (dividends). So theoretically, if they buy a share from you now when it is cheap, then later when you're making lots of money, they will get their money back over time with the dividends. If your shares can be bought by anyone, then they are publicly traded. If someone is buying stocks, they probably buy lots of different ones so that if one company fails, other companies will keep going and they won't lose too much. Keeping track of all this can be a full time job, so people hire other people (brokers, fund managers, etc.) to deal with this for them. Wall Street is where many of these brokers and fund managers work. Because they tend to be in contact with each other (this was more common in the past but works a little differently with the internet and high-frequency computer trading) this can cause ripples in the economy for investors. For example if one broker lets it slip to many others that, say, Samsung might be releasing a new device that will make them a lot of money (resulting in high profits, and thus high dividends) many brokers will encourage their clients to buy Samsung shares so that the brokers can get some of that money. Then if it turns out that Samsung aren't releasing anything new and actually accidentally made a lot of phones explode, people don't want that stock any more and will want to sell it to someone else quickly so they can use their money to buy something more profitable.", "I feel that these comments are leaving something out. Are there scumbags and parasites on wall street? Of course. But wall street also provides legitimate services. Companies need capital (money) to grow. Wall street provides that money. The main ways companies raise money are by going public (stock) or selling bonds (debt). Venture capital can only get you so far. Amazon, Apple, Home Depot, Google are all publicly traded companies and wouldn't be as big as they are or might not even exist, if they didn't go public. An investment bank helps you go public or sell bonds. These companies need money, but have no idea how to go public (or sell bonds). They go to an investment bank and the investment bank makes it happen. Wall street isn't all hookers and blow like wolf of wall street. There are a lot of really smart guys (nerds) working long hours in front of computers. These guys make good money but nothing to brag about, especially in NYC. Most of these guys can't even afford to live in the city and are laid off every time there is a downturn.", "So imagine there's a cake. And when someone slices off a piece of that cake, Wall street takes that piece of cake and hands it to someone else. In that process, a small crumb falls off the piece and Wall Street people take that for themselves. Soon enough they will have their own cake made up of parts of other people's cake. Then they can sell their own cake to others. They can also slice up and package their own freakish cake as something \"special\" like the daily special at a restaurant. (LPT: don't ever order the seafood special at a restaurant and if anyone in Finance tries to sell you something special, run) They also do other weird things with the cake and crumbs. Like letting people bet on whether the crumb lands on the floor, or the table. Or other things like having other people buy a piece of small cake today and promise them a bigger piece tomorrow.", "Oooh I can finally answer a question! A lot of the answers here are riddled with misinformation. The answer to your question is people on Wall Street do a ton of different things. Investment Banking: this department is essentially corporate finance advisory. There are a few different areas of IB, the most well known area of ibanking is mergers and acquisitions, investment bankers advise companies on buying and merging with other companies. When you hear about Facebook buying WhatsApp, or mega mergers, investment banks were behind the scenes trying to help the deal go through. There are also other areas of banking like restructuring, equity capital markets (releasing stock to raise capital), debt capital markets (issuing bonds and debt to raise capital). Research/Sales/Trading: this is the part of investment banks that buy, sell, trade, and release research reports. They trade investor money and try to make money essentially any way they can. Some people trade derivatives, others mortgage backed securities, and many other products. Then there are other areas of finance like asset management which can range from helping people manage personal savings to helping manage pension funds etc. Do they create things? Kind of. Wall Street enables a hundred different industries by providing debt and helping to raise capital. The asset management side of things help ensure that pension funds don't run insolvent to ensure that senior citizens have cash that they have rightly earned over their careers. Obviously, there have been many unethical actions taken by financial institutions over the years, but historically have created far more wealth and value than they have destroyed. It is incredibly difficult to get hired. The majority of front office functions of banks (functions that are revenue generating) are held by Ivy League graduates with top gpas. Many front office positions require a ton of hours and are incredibly high stress. Source: have worked a variety of different positions at a variety of banks.", "Wall Street does a ton of things and it's huge. Trying to say all of what wall street does in this answer is not possible. Instead, I'll talk about two big things that wall street does. 1) Wall Street moves money from people who have it to people who need it. 2) Wall Street moves risk from people who have it to people who want it As for 1) when a company issues stock or bonds, they're doing that because they want to raise money. They want to invest that money in the business (hopefully) to hire more people or build more factories or w/e. These companies go to Wall Street (Let's say they go to our friends at Goldman sachs) and Wall Street will hook them up with the investors (hedge funds, pension funds, other asset managers, whatever). These investors are looking for a place to put their money and hopefully generate more money. Goldman Sachs will then facilitate the linking process between these two groups. This is just one example of how Wall Street moves money from the people who have it to the people who need it. Another example might be when you invest your money by giving it to Vanguard. You have surplus money right now, and you feel that in the future, you will need more money (you'll be retired or w/e.). Vanguard will then take that money and invest it so that in the future it'll be the same (or hopefully more) amount of money. There are a ton of other examples of how Wall Street moves money from the people who have it to the people who need it. 2) Risk - Let's say you're McDonalds. You make burgers that ppl like to buy. But, as a part of your business model, you want to charge a constant price for these burgers. You want to always charge $5 for a big mac. But, the price of wheat/beef/lettuce/whatever ISN'T constant. If there's some disease that kills a bunch of cows, then the price of beef will go up. How do you, as McDonalds, still provide a constant price to your customers? Well, you'll go over to your friends on Wall Street, and try to arrange a deal, where you can acquire beef/lettuce/whatever at a price that you set now. In that sense, you can eliminate the risk of the price going up and you can charge your customers a constant price for your products. On the other side, let's say you're an expert on lettuce farming techniques, and you're sure that the price of lettuce is about to crash. You have info on a new GMO that will make lettuce a lot easier to produce. To exploit this knowledge, you'll take on the risk that McDonalds previously had by selling them lettuce at a set price for future delivery. If all goes well, the price of lettuce will go down and you will be able to buy lettuce for cheap, and then give it to McDonalds at the higher price you set today. Wall Street facilitates these transactions. This is a small example of how Wall Street can help transfer risk from people who don't want risk to speculators. This is a pretty short summary of what Wall Street does. There are a ton of other services that Wall Street provides to the public. If someone says Wall Street doesn't do anything important, then they really don't know what Wall Street does. Wall Street provides an essential service to the public. But yeah, obviously they do get greedy and stupid sometimes.", "Whatever everyone else says, there's at least a couple of guys on wall street who sell falafel. I've met them.", "The service provided by the stock market is resource allocation. By buying and selling, they find the market value of things. It allows successful companies to raise capital. Wall St firms all have analyists, whose job it is to go over company's numbers, and make judgements about their future earnings, trying to find potential investments. This is basically why people hire brokers, because it's time consuming to do this reseach yourself. And the of course there is the shady side of it, collusion, insider trading, pump and dump. Those guys are all jerks.", "People on Wall Street get rich. That is their #1 goal. Ideally Wall Street's function is to allocate capital properly. In reality, due to unrestrained greed, regulatory capture, etc., and with the help of Sen Schumer Wall Street makes money by cheating, scamming, high frequency trading, and the such. Goldman is the top bank of Wall Street, and in the word of Matt Taibi, \"the world's most powerful investment bank is a great vampire squid wrapped around the face of humanity, relentlessly jamming its blood funnel into anything that smells like money.\" Edit: typo, accurate quotation", "At the broadest level, the financial system takes money from people who aren't spending it (savers/investors/lenders) and channels it to people who need it (borrowers), either to smooth out their income or to make productive investments. There are two main ways to do this: institutions and markets. Commercial banks are institutions that take money from savers (deposits, CDs etc) and lend it to borrowers. The US (for historical and regulatory reasons) has thousands of commercial banks, spread throughout the country. Some of the biggest ones (like JP Morgan or Citi) are based in NY, others (like Wells Fargo or Bank of America) are not. The other channel is markets. Companies issue stocks (which are risky but offer upside because they pay a share of the profits) and bonds (which offer a guaranteed return, hence safer (but not completely safe because the company could always go bust) but less upside) to investors. Other entities - especially governments - also issue bonds. Fund managers (such as Vanguard or Fidelity) put these stocks and bonds together into funds that are diversified, hence less risky, and sell them to investors. Some funds (hedge funds) take on additional risk (but, in principle, better return) by borrowing money rather than just selling shares to investors. The main stock and bond markets in the US are based in NY, but the fund managers are headquartered all over the country. Investment banks (like Goldman Sachs and Morgan Stanley) do many things, but historically have two functions: banking and trading. The banking side helps big companies issue stocks and bonds. They gauge the market demand, set appropriate prices, find big investors to take up the securities, manage the logistical aspects. Related to this, when there's a merger or takeover, investment banks provide advice and help arrange the financing. On the trading side, investment banks have proprietary \"desks\" that specialize in buying and selling stocks, bonds and other kinds of securities. Partly this helps them understand the markets so they can do better at banking and advisory, but also (some would argue mainly) it's a way to make money. Most investment banks are based in NY, so they can be \"close\" to the markets (there are some smaller regional ones). The Depression-era Glass-Steagall Law put tough limits on what commercial and investment banks could do, and mandated that these institutional types be separate (in other countries, esp in Europe, \"universal banks\" have historically done both commercial and investment banking). Glass Steagall was gradually worn down over the years, until the Gramm-Leach-Bliley Act of the late 1990s essentially allowed commercial and investment banks to do pretty much anything the other could do. They were still regulated by separate bodies, however, with the commercial banks under a still relatively strict regime run by the Fed and the Comptroller of the Currency (for larger banks) and the FDIC and state regulators (for smaller ones). The investment banks were under a \"light touch\" regime run by the SEC, which focused on making sure markets ran smoothly. Since the 2007-09 financial crisis and the Dodd Frank Act, the remaining big investment banks converted themselves into Bank Holding Companies (hence under the Fed for regulation) and have been supervised much more closely. Do they create anything? Well, they help allocate money more efficiently. That sounds pretty weak, but in a $17 trillion economy it can actually be pretty important. As we learned in 2008, when it goes wrong it can have some big consequences. There is research saying the financial system is probably bigger than it needs to be - and after a point, a larger financial system does not seem to help countries much in terms of growth. But that doesn't mean it's worthless either.", "There is a Netflix documentary called The Pit. It explains commodities trading and all those people standing on the floor yelling at each other.", "Buy, sell, borrow and loan, basically. On the plus side, they can diversify risk away and let people move money through time, which can unlock tons of economic opportunity and innovation. On the downside, they can amplify risk and create a lot of useless friction, especially when they give into either excessive automation or let cognitive biases get away from them. Or when they're selfish a-holes. Basically, those who treat finance as a zero-sum game destroy value, and those who treat it as a win-win create value.", "Wall Street's intended function is the optimal allocation of resources. With many investors choosing where to put their money, the theory is that this will result in the most worthwhile and beneficial projects receiving the most capital. The incentive is pretty simple. If you direct your capital to a project you believe in (by buying a share of stock), you can later sell it for more money, once that enterprise has used your money to become successful. Or you can keep it and be entitled to a portion of the enterprise's proceeds (dividends). And for the most part, it works. The tricky part is that it leverages greed. And greed has a way of gaming it the system. The players can become less interested in the worthy allocation of capital and more interested in making a quick buck. That is why we regulate trading pretty heavily (and some would say not heavily enough).", "Here is the \"non complicated\" answer - Wall street is a place where people with money come to make more money and where people who need money come to ask for money so they can also make more money. And here are the answers to your questions. Do they create anything? Yes. They create liquidity and opportunities for both parties in my definition above to make money. They provide services for both parties so those parties can provide tangible products and services to you, the consumer. Are they just playing with people's money? No. No one would trust their hard earned (or easily earned) money with someone who just fucks around. People want a return on their investment not someone to \"play\" with their money. Does it serve any purpose to society? Yes. The roads you drive on, the buildings you live in are all built by money that is facilitated from wall street. The products and services that are provided to you (iphones, toaster ovens, etc.) have all come from the help of wall street (loans and stock/bond offerings). If you want to learn more about finance you can try khan academy or URL_0 . Don't listen to these fucking morons on the internet who think wall street serves \"not too much\" of a purpose to society.", "From a very basic view, they facilitate the movement of excess money (or capital) from people/funds/corporations (investors) to companies/corporations that require additional capital to create value.", "Bank takes your money to protect it and pays your 3% interest, takes the money you're not using and loans it out for 6%. Then they go out for golf at 3. It's called the 3-6-3 plan.", "Really, Wall St right now is more residential than business. Many of the larger financial firms have moved to midtown NYC and buildings are being quickly turned residential. Edit: I should also add that the stock exchanges all exist in data centers in New Jersey.", "They solve this problem, mainly for companies: \"I want to do something productive with a lot of money, but I don't have the money yet.\" This is why companies sell ownership in themselves (stock) and promises to pay you back later a little more than you pay now (bonds). Doing this is very complicated, and Wall Street firms will hold your hand through processes like IPO and bond issue in exchange for a percentage of what you raise. Then, *lots* of interesting things happen because what people are willing to pay for those stocks and bonds can change over time. Wall street companies help themselves (proprietary trading) and their clients (investment banking) turn money into more money based on these price movements. This is (kind of) the same money that helps companies do expensive stuff.", "Assuming you don't just mean stock markets, but generally the financial industry on wall street. Some people are brokers, like middleman finding two people who want to have a transaction. Imagine you have a trainload of corn to sell - you need to sell that to someone who wants a trainload of corn. Instead of calling all of your friends, you call up a Wall Street broker, who can put this corn up for sale, helping find a buisness who wants all that corn. Other people are investors. Maybe they take the corn, and hold onto it for a few days, and when the price of corn goes up, they sell it. They can also invest another way, by \"borrowing\" someone's corn at the current market rate, selling it now, and waiting for the price to go down before buying the corn back to return to the original owner. Still others are bankers, holding on to money for lots of people, and in turn lending some portion of that money out for others. The people giving their money to the bank get more money back (because people who were lent money must pay interest back), and the bankers make some money on those loans. People getting loans get money they need \"right now\" with the expectation that they can \"pay it back later.\" But what really makes wall street tick is not each of these individual transactions, but rather these transactions in all together. For every transaction that makes money, there's transactions that lose money. Thus, the banker holding on to people's money and lending it out, might lend it out to people who don't pay him back. Or maybe the price of corn goes down after you bought it and now you have to sell it at a loss, because what are you gonna do with all that corn? Wall Street has enough outlets like this such that wall street businesses can protect these \"bets\" by placing opposite bets - maybe you buy the corn, but then protect that by also betting at worse odds that the market for corn will go down. You can spread these buying and selling across different places, so that maybe you protect your corn by buying gold, or putting money in a bank. Similarly, anything can essentially be sold. Those loans that were offered by that bank? Well, those people are going to be paying interest over time. Maybe the bank would rather sell off those loans now to someone else who wants to get those interest payments. Maybe there's four house loans together that cost the bank $1million to loan out, but over 30 years the bank gets $1.3 million back (the loan plus interest). The bank could sell that to someone else for $1.1 million, thus making back their money, but now not risking those people forgetting to make their payments over 30 years. The person buying those loans takes the risk that those loans might go bad, for $0.2million gain. These sort of transactions help sellers with things, sell them when they want to, for a \"fair\" rate. It also helps buyers who want things find the things they want. In the middle, people make money off of the transactions. Some people don't like the fact that the middle man makes money. You can imagine wall street like a fancy Walmart. Walmart doesn't \"make\" those nike shoes, panasonic tvs, or lays potato chips, they buy them for less than they sell them for. What do you the consumer get? You get access to those goods in the same place, for a low price, because Walmart is able to negotiate the purchase of millions of units. Without Walmart in the middle, you'd have to find a way to get distributor-level access to all of those products, or go through a specialty shop, which would mark up the goods even more. That's not to say middlemen are always good, but perhaps a necessary evil that must be somewhat limited with a few strict rules.", "Wall Street is a massive term for banks on and around Manhattan in NYC. Hell, even banks and funds in NJ gets lumped with Wall Street, sometimes as far as Greenwich, CT. So for argument, let's define Wall Street as most serious financial institutions in the proximity of Manhattan. These institutions can vary very much in size. From the smallest one man funds, to large investment banks with thousands of employees. The various companies focus on different things: Some only deal in certain markets and niches, while others have many different divisions that tackle these. **Investment Banks (IB)** = In general, they underwrite. That is, they raise capital for their clients (companies) from potential investors. But they also do many, many other things. Regular credit/commercial banks can't do this, because of the laws. So when you go to Bank of America (or whatever), it's not the same branch of the bank that deals with IB stuff. **Mergers and Acquisitions (MA)** = When two companies want to merge, or one wants to acquire another, they contact banks to help them structure the process. **Private Equity (PE)** = PE groups, or funds, strictly deal with private capital, and private companies. Large PE groups own private companies. If you go to a Investment Bank, and say that you want to sell your company to the best bidder, they usually get in touch with PE groups in larger banks, or smaller PE firms. **Real Estate (RE)** = Same as PE, but they own assets that are tied up to Real Estate. Want to start a fund that invests in the rising real estate prices? You contact the RE groups. **Private Wealth Management (PWM)** = The group and managers that handles the wealth/portfolio of private individuals. **Hedge Funds (HF)** = Investment funds that minimize/offset risk by hedging. Basically, if you forecast that one investment is going to rise by a rate of two, and also forecast that another investment is going to sink by one (maybe it's even tied up to investment one, in one way or another), you invest in both. In the end, you should end up with a net sum of positive one. This is a safety measure. Hedge funds have been extremely popular for the 20 last years, and you've seen all sorts of \"exotic\" types. **Venture Capital** = These funds and groups raise money for promising and new companies, i.e Startups. This is by nature very risky, but the reward can be huge. And the list goes on. So the banks either raise capital, advise, or invest on their own behalf, or on clients behalf. Clients can be individuals, trust funds, funds, global funds, companies, and what not. How do they affect you? In many ways. Look at these examples As a inventor / entrepreneur: You come up with a great idea, but don't have enough money to develop it. What do you do? One option is to contact **Venture Capitalists**. You meet up with them, pitch your idea, and they love it. They offer to back up your startup, for a share of the company. No growth = no success, so you agree. Maybe they get 70% of the company, and you / early members get the 30%. Your startup turns out to be wildly successful, and 5-10 years down the road, you and the VC's agree that it's time to let in other investors. That is, you turn your company to a publicly traded company. Well how does one do that? You contact the **Investment Banks**! Or maybe a smaller firm that focuses on the whole process. In the end, you settle for a couple of different groups, from different banks. Banks like Morgan Stanley, Credit Suisse, Goldman Sachs. Either way, your company is now being traded. Everyone can buy shares, and own a bit of your company. You decide to retire, and sell all your shares. Maybe you net a nice billion or two. What happens next? A) For your part, you can spend the money as you like. Maybe you want to invest them on your own, or maybe you contact a PWM manager to do that for you. B) For the companies part: Maybe some PE group now owns them, or a huge chunk of the company. Sometime down the road, maybe a competitor offers a Merger. Who knows. Either way, all these banks and firms have been part of the deals. Sorry for the long write-up, as it's a huge, huge topic. But the real **TL;DR ELI5** would be: Wall Street banks raise capital/underwrite, offer advisory to clients, invest money or their own, or their clients behalf. Everything that is related to Finance, they do. There's no monstrous catch-all bank that excels at absolutely everything...different firms on wall street are good at different things. You find these banks in, and in the areas around: Wall Street (NYC), City (of London), Frankfurt, Singapore, etc."], "text_urls": [[], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], ["investopedia.com"], [], [], [], [], [], []], "score": [3209, 3097, 168, 156, 147, 100, 65, 61, 21, 20, 12, 11, 8, 7, 7, 6, 5, 5, 5, 4, 4, 4, 4, 3, 3, 3, 3, 3, 3]}}, {"q_id": "5tstlh", "category": "Repost", "title": "Why is there a male chess competition and a female one?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddoqov3"], "text": ["There aren't. There is the open competition, and a separate one for women only. Top female chess players have competed in the open competitions. For example, [Judit Polgar]( URL_0 ) Since most people who play chess are male, and women have felt alienated by the mostly-male environment of open chess competitions, women-only chess competitions were set up to help grow the hobby among women."], "text_urls": [["https://en.wikipedia.org/wiki/Judit_Polg%C3%A1r"]], "score": [7]}}, {"q_id": "5tupif", "category": "Repost", "title": "Why do food or drinks taste different when hot or cold?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddp5053"], "text": ["URL_0 URL_1 Basically our tastes buds are more sensitive to certain tastes at different temperatures, which send different signals to the brain."], "text_urls": [["https://www.google.com/amp/amp.livescience.com/20286-foods-taste-hot-cold.html?client=safari", "http://mobile.foodnavigator.com/Science/Food-temperature-affects-taste-reveal-scientists"]], "score": [3]}}, {"q_id": "5txg3e", "category": "Repost", "title": "Why do people \"Black Out\" after a night of heavy drinking and can't remember what they've done the next morning?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddpsh1n", "ddpsf0w", "ddq370b", "ddpxx16", "ddq03ml"], "text": ["Alcohol messes with a part of your brain called the Hippocampus that, among other things, manages transferring short-term memories into long-term ones. The result is that some or all of the short term memories from the time you are intoxicated don't get transferred, and once your body has removed all the alcohol and you're sober again, you can't remember some or all of what happened.", "Consumption of alcohol impairs a person's ability to form long-term memories. It's like writing an essay but forgetting to save it somewhere when you're done. You know what is going on in the moment but as soon as you're done all of that information is gone.", "A lot of the comments here are close to the money but don't touch it just right. Alcohol is a toxin to the body. The main area where it is detoxified is in the liver. The detoxification of alcohol produces a few side products that start to accumulate in the liver cells. The most important one is a molecule called NADH, which is used by liver cells for energy production as well as glucose production. An imbalance in this molecule is created because of the alcohol, so the cells get confused and think there's enough energy, so they stop the cellular power plant, but this also stop prevents the liver from producing glucose naturally. Your brain requires glucose directly from the blood in order to function properly, so once it starts running low on fuel, it begins to malfunction. This malfunctioning is what shows up as drunkenness. As more and more parts of the brain run out of supplies, you start to become more and more drunk. The outer most parts of the brain get affected the most very early on, and the inner parts of the brain are affected later, because brain blood flow works from inside to out. The hippocampus is a part of the brain that's located very deep inside the brain. Because it's a very old and basic part of every brain, it gets a lot of blood to stay in tip top shape. When you drink enough alcohol to reduce fuel to this area, your brain cells stop firing properly, and they lose the ability to register new information. It's kind of like writing with disappearing ink. It's there for 10 minutes while you do it, because there are other parts of your brain that allow you to think and act immediately, but it can't be saved to paper. This process isn't absolute though. In between, people can eat food, or the alcohol starts to get metabolized and a little more blood glucose comes in. This lets the brain save memory in parts, and allows for atleast partial recollection of the events the next day. It's sort of like keeping a brief snapshot, which your friends help fill in the gap with. Also, alcohol can directly slow down functioning in the brain by mimicking little molecules that switch off or prevent neurons from firing. TL;DR The only thing that's known about memories right now is that they are formed in part by brain cells firing off in particular patterns. These patterns are what make memories. Firing off neurons needs fuel in the form of glucose. The brain needs fuel to work and save memories. Alcohol tells your body's main fuel factory in the liver that there's enough energy, so your brain runs out of fuel overtime. The part of your brain that makes memories runs out of fuel only when the blood sugars are too low, and that's what makes you blackout. Plus alcohol also directly prevents neurons from firing off by mimicking molecules that act like brakes. So it's a bit of a combination of both fuel stoppage, and hitting the brakes too hard.", "I have a follow up question: why do some people black out more than others (and some, like me, seem to never black out)?", "I'm just here to complain, none of these answers tell me what I came here to read. \"Alcohol inhibits the brains ability to form new memories\". That doesn't help. What are the mechanisms, why does it happens? We already know it happens. Edit:u/RedditorDoc hits closer to what I had been hoping for."], "text_urls": [[], [], [], [], []], "score": [85, 33, 32, 10, 8]}}, {"q_id": "5txqel", "category": "Repost", "title": "How do QR codes and Barcodes work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddq5ha4"], "text": ["When a barcode/QR code is scanned, you are actually scanning a string of characters (ex. 123456, abcde, etc.) each character has its own distinct set of 'bars', so || | could equal 1 and | || could equal 2, ||| || is 3, so on and so forth. Once the barcode is scanned (this is done by shooting a red light at the barcode and having a sensor detect the reflected light; black reflects the least light, white reflects the most) the black and white lines are translated into binary (1s and 0s, so black black white could be 110) and sent to the computer where the information can be translated into some useful information like price, name, etc. QR codes work essentially the same way, but instead of bars its black and white dots. \"But why not just scan numbers and letters themselves?\" you might ask. Well, barcodes tend to be much more reliable than letters and numbers. 0 and O might be mixed up or I, l, 1, you get the idea. Having each character be represented by bars/squares simply produces less errors. so with the basics of barcodes out of the way... 1. I can use an app on my phone to scan one of them; why do stores need a fancy machine to scan them? although stores could technically use phones to do all the scanning and pricing for them, dragging the item across the scanner (like they do in most stores) is simply much easier and faster than aiming the phone at the barcode for each item. As for calling those machines fancy, they actually just translate black and white lines into 1s and 0s. That metal square you (and all of us) have religiously bound ourselves to is a much more complex device :) 2. If my phone can read them, does that mean it's just a picture that, once scanned, can take you to a website and such? yep, your phone scans the QR code, translates the black and white boxes into a website link, and goes to that website 3. If so, do all brands need to work together to make sure two different products aren't given the same code? Yes. Well, sort of. So let's say you are the CEO at Snapple and you want to release a new flavor. Before you can start manufacturing the new Snapple flavor you have to order what us called a UPC, or Universal Product Code. This is basically a unique 12 digit code that isn't on any other commercial product. So brands don't necessarily work together to maintain fully unique product codes, but rather all brands answer to some upper corporation that makes sure all of their products have unique barcodes sorry if i forgot some stuff or didn't elaborate on something else, its 2am here and I'm pretty worn out"], "text_urls": [[]], "score": [5]}}, {"q_id": "5ty8la", "category": "Repost", "title": "How do placebos function?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddpyknm", "ddpy0z9"], "text": ["For the most part, they don't work. The placebo effect isn't about positive thinking or willpower or anything like that. Placebos have almost no objective effects. But assessing how you *feel* is very subjective, and easily influenced. Placebos play into that by making you *think* you feel a little better. > if there was a drug to cure the common cold virus, and a placebo also worked to cure that cold virus because they believed it was the medicine, That is not what happens, the placebo doesn't cure anything. If you are sick and take a placebo, your temperature won't go down any sooner, less snot won't come out of your nose. All that happens is the expectation that the pill will make you better causes your self-assessment of how you feel to go up a little.", "> Can the actual willpower of thinking you'll be cured from that actually cure you? Pretty much, yes. That or just circumstance. For example, most people who have the cold will have the cold go away on its own relatively soon, so they would think it was from the medication when it was going to go away anyway. In this case, though, if the \"drug to cure the common cold virus\" had *the same* effect as a placebo, it means the drug almost certainly did nothing at all to cure the cold and it was just the placebo effect there, too."], "text_urls": [[], []], "score": [4, 3]}}, {"q_id": "5tzvwg", "category": "Repost", "title": "What is the difference between an expat and an immigrant?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddq8ppf"], "text": ["As a political commentary they may be right. But as a literal definition no. An expat is a person living in a country where they are not a citizen, and often retaining the option to return to their native land. An immigrant is a person living in a country where they are (or seek to be) a citizen, and typically to spend the rest of their live and their descendants' lives there. URL_0"], "text_urls": [["https://panampost.com/yael-ossowski/2015/03/26/the-difference-between-expats-and-immigrants-its-passports-not-race/"]], "score": [3]}}, {"q_id": "5u31wq", "category": "Repost", "title": "What makes the \"I'm not a robot\" captcha hard for bots? Can't spammers just create a program that clicks on the box?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddqxsac", "ddqy1nx", "ddqxrf6", "ddr9twi", "ddr4ng7"], "text": ["The \"I'm not a robot\" captcha takes into account more than just the click itself. It takes into account factors like \"time spent on page before click\", \"mouse path to button\", \"accuracy of click\", et cetera, to predict whether you're an automated software or an actual person.", "If you're logged into a google account, google looks at your account activity to decide whether you're a person or not. If it's not sure you're a person, you get to click on a bunch of pictures of store fronts or road signs.", "Sure, but the way that the bot clicks that box is very telling. If the mouse snaps exactly to that square, instead of moving to it like a human would, then it's a bot. If the whole page gets filled in at the same time the mouse is moving to the box, then it's probably a bot. Things like that.", "One other thing not mentioned: spambots aren't usually using browsers like how an ordinary person would. It does not usually work through a graphical user interface, it just submits form data after form data. Think of this captcha more like a speed bump. If it restricts bots to the same speed as a human spammer could (which captchas can't prevent anyway), then it's done its job.", "Sure they could make a bot do it, but they have to vary the time, and path of the cursor into the box, and the co-ordinates of the click too. which is dramatically harder than just sending a \"mousedown\" event at \"location of checkbox\""], "text_urls": [[], [], [], [], []], "score": [92, 12, 12, 9, 3]}}, {"q_id": "5u4ahy", "category": "Repost", "title": "Why isn't 17th-19th century style classical music not composed anymore?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddr8odc", "ddr9mpw", "ddra3j8"], "text": ["Composers of 20th/21st century classical music are always pushing the genre forward and looking to do something new. If they wrote something which was too close to the music of centuries ago, it would be dismissed as a \"pastiche\" and not a new work of art.", "[It is still composed.]( URL_0 ) Aside from film scoring it just tends to be less visible, overshadowed and squeezed out of airplay by the traditional masters of the genre.", "Its definitely still being made, it's just not so mainstream. Most composers of such music nowaday tend to work in Film and TV creating musical scores. John Williams, Hans Zimmer, Danny Elfman for example..."], "text_urls": [[], ["https://en.wikipedia.org/wiki/Classical_music"], []], "score": [6, 3, 3]}}, {"q_id": "5u4kxa", "category": "Repost", "title": "Why is Venezuela's economy in utter collapse when they're a major oil exporting country?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddrav4h"], "text": ["Since the end of 2014, the price of oil has collapsed. Prices went from aroun $100 per barrel down to $38 per barrel and stayed depressed ever since then. So essentially their national income has fallen by 50%. Couple that with their debilitating socialist obligations and anti-business tendencies and it's a recipe for financial ruin."], "text_urls": [[]], "score": [5]}}, {"q_id": "5u6uyl", "category": "Repost", "title": "Why do a significant number of people still deny climate change?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddrrgde"], "text": ["It's become subject to partisan politics. There have been interesting studies that show once people's emotions are involved facts lose a lot of meaning. We think of ourselves as rational beings but in reality it's very easy to ignore evidence that doesn't conform to your world view and to selectively give weight to evidence that supports your emotional position."], "text_urls": [[]], "score": [7]}}, {"q_id": "5u88jv", "category": "Repost", "title": "in low light conditions, why is it easier to see objects by looking next to them, rather than right at them?", "title_urls": {"url": []}, "selftext": "Hope I explained my question well. I find it hard to see things by looking directly at them in low light. By looking next to the object I want to look at, it becomes more clear.", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dds2zby", "dds2idb"], "text": ["There are two types of light detecting cell in your eye, cones give you color vision and are highest in density at the fovea(the part of the retina that corresponds to the center of your vision). Rods are more sensitive, react faster, don't filter colors, and are a higher density outside the fovea. Basically, the center of your eye is optimized for inspecting things and noticing subtle differences in color, while the rest is optimized for high sensitivity/fast reaction time. It's the high sensitivity part that lets you see stuff more easily in low light.", "This is an effect of how our eyes have evolved. Our eyes color receptors (\"cones\") are located in the central part of our eye and they make it easier to see detail and color but are not as light sensitive in low light conditions. Our peripheral vision uses \"rods\" which are not color sensitive and less detail sensitive but are more light sensitive in low light conditions. This may be because when reacting to something you see in your periphery it is more important to see that SOMETHING is there rather than what exactly is there so you can either flee or turn your head and eyes to then use the more detail oriented part of your eye to see what it is."], "text_urls": [[], []], "score": [13, 4]}}, {"q_id": "5ua9q2", "category": "Repost", "title": "Why is it called the 3rd world, where is the 2nd?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddshu61", "ddshy5a"], "text": ["This term is a heritage from the Cold War. There were the NATO-aligned first world, the Soviet Bloc-aligned second world, and the third world were the remaining non-aligned countries.", "2nd World refers to the former communist countries of the Soviet Union and other socialist and industrialist states. There's quite a bit of info if you just Google it."], "text_urls": [[], []], "score": [23, 5]}}, {"q_id": "5ub3pl", "category": "Repost", "title": "why do the white ceiling tiles (seen in all schools) turn brown when wet?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddsp3kd"], "text": ["I believe it's because the outer white covering that's \"moisture resisant\" becomes transparent and shows the inner brown material. The inner material also looks darker when moist."], "text_urls": [[]], "score": [6]}}, {"q_id": "5ubdlv", "category": "Repost", "title": "How did the first programmers program programs? For example, how did they program the Operating System or CMD if they had no programs or programming languages.", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddswn76", "ddt4x4l", "ddsvqo5", "ddssgeb", "ddstjq5", "ddt6tor", "ddsv7lz", "ddt324e", "ddsybe7", "ddt3ek6", "ddt5ax7", "ddt6dpu", "ddt8lgf", "ddtabf3"], "text": ["Step 1: Build a computer that can only be programmed by physically moving wires around to change the patterns of 1's and 0's. Step 2: Get sick of that, so create a computer that can read those ones and zeros off a physical medium, such as a long strip of paper, or cards. This is called programming in \"Machine Language\". Step 3: Get sick of writing ones and zeros for the commands, so give names to the various opcodes, such as \"LSR\", for Left Shift Register. This is called \"Assembly Language\". Write a program that does a 1 to 1 translation of assembly command to machine command. Step 4: Realize that you keep doing the same sequence of assembly language instructions over and over, so you create a program that can convert a special command, such as \"loop X times\" into that sequence of assembly language commands. Step 5: Keep adding more commands, and realize that symbolic addresses are useful, too. Before you know it, you have a compiler for a high level language, written in assembly language. Step 6: Do future iterations of this process in the higher language to build even higher level languages.", "How do you mass produce tools? First, you sort of cobble a tool together using whatever you've got. Then you have your proto-tools, you use those to bootstrap yourself up to the next level, hand-crafting your nice tools. Ok, now you have some actual tools, but you still haven't gotten mass-production. So you use your nice tools to build some tool-building tools, and then once you have those, you build some tool-building-tool-weilding automation systems (you could call them robots, or factory lines, depending which era you're talking about). And so on. It's basically just bootstrapping again and again and again. Somebody took the first circuits and said \"if I connect these two wires in this way, I get this output\". Somebody else said \"well let me take some circuit boards and print them in such a way that it's easy to switch the inputs around to get different outputs\". Then somebody said \"cool, now that you have that, I'm going to come up with a set of common rules on how best to get a certain output using these circuit paths. As long as your circuit machines follow this convention, other people can quickly bang out circuits using that same convention without having to build it from scratch every time\". That's assembly. Then somebody else said \"ok cool, but some people don't really understand circuits, so I'm going to abstract that one level further\". If you are a programmer, any time you abstract some concept into an easier to use API, you are doing the exact same sort of process the early programmers were doing. They just didn't have so many shoulders to stand on as you do. When I write fetch('/foo').then(r = > r.text()).then(console.log.bind(console)), I am not actually thinking about all the various pieces that breaks down into. But somebody else at some point said \"you know what, javascript needs a way to make http requests\". And somebody before them said \"you know what, there should be a quick and easy way to make a standardized tcp connection to a server, receive some data, and close the connection\". Somebody before that said \"I wish there were a protocol that would help me send packets of data across a network in a standardized way\". Before that somebody said \"I wish there were some way to beam bits of light across ethernet cables\". etc. Obviously take these generalizations with a grain of salt, I'm sort of making it up to prove a point.", "The operating systems, and compilers are all there to make life easier. As a child I had a z80 computer which came as a box of components and a circuit diagram. The input was three banks of buttons one (8 button bank) for the byte, one for the address and a small number of functions like write memory, show memory, run program and the like. To write a program for this monster I would get a piece of paper and work out what i wanted it to do. I would then write (by hand) the machine code instructions and then refer to another sheet of paper with the binary equivalents for each instruction. I then used some graph paper on which i had columns for memory address, op code (the command) and the data, all written as 1's and 0's. I would then use the keyboard to enter the memory address (in binary) and the command or data i wanted to enter. After many hours I would then hit the run button and watch as the bank of 8 Light bulbs would flicker in a set sequence, and have to start all over again as the computer had no long term memory. Earlier than that, NASA and other organisaitons used \"braid memory\" which is literally bundles of wires braided together into the binary patterns for the program to be run. This means that rocket's flew into space running computer programs entered into them by little old ladies basically knitting miles and miles of wire. ( URL_0 ) And even earlier than that the Bombe (a code breaking computer from 1939) had rotating switches for memory, you programmed it by turning dials for each memory location before running it. Although the bombe was only capable of running one \"program\" without physically re-building it, and the memory was more like a saved configuration file for that program in today's terms.", "With hand entered machine code, computers take binary numbers as commands and data. If you know their instruction set specification and are patient you can write them by hand. Very early computers had a bank of switches, set 8 or so binary values and then flip the \"submit\" switch.", "Are you asking us how programmers programmed programs when they didn't have any programming programs to program programs with? If you look at the predecessor to Windows, MS-DOS, you will notice how simple it is, and how little it could do. So somebody wrote compilers for it, which allowed people to write more complex programs for it. Then people wrote graphical Software Development Kits, and slowly the beast just grew and grew. What was important here was the fact that everyone settled on using the same computer - what was known as the IBM-compatible, or as it's called today: The PC. I had an 8-bit machine back in the eighties, and we could buy magazines with programs to enter. It would come in the shape of a page of machine code, and a tiny BASIC program that you could enter the machine code into in order to write it to disk. Oh, yeah, and if you got any of the bytes wrong, you'd just crash and would essentially have to start over. I'd say \"Good times\", but damn it, it wasn't. The 8-bit processor would itself come with a ROM - read-only-memory, which would provide basic functionality. To the best of my knowledge, this was actually hardware. As in, the programs were written with logic gates. I did have a PASCAL compiler back in the mid-eighties, but the compiler itself took up most of the disc space itself, so you couldn't really do much with it. :p TL;DR: With logic gates and machine code. And very slowly.", "I am enjoying this topic, so let me try my hand at explaining it. ------------------- First, you must understand that a computer is essentially a really complicated series of switches. Each switch does something specific with a bit (1 or 0). Flipping a switch may send a bit to one place or another. A different switch may save that bit for later. Yet another switch may flip a series of other switches which all preform a more complicated action like binary multiplication. It may even do something really fancy, like light up a pixel on an external display. As you can imagine, a computer has a lot of these switches in the processor. Millions or billions of them in fact. Basically, way too many to set individually. So, when we design a chip, we make a few switches that control all the rest of them. We call this an instruction. An instruction for a simple processor may just be 8 bits, something like '11001100' which means we turn on the 3rd, 4th, 7th, and 8th switches, while leaving the others off. When you use the switches this way, it may cause a cascading action that adds two bits together, and outputs the result. Now that there are easier instructions, users can just input the instructions that they want the computer to run, one at a time! This is effectively a language, called machine code. Old-school processors came with a thick book of instruction decodes (Add A to B is 11010001), and you would have to run it that way. Okay, so users can put in one command at a time. Too Slow! So what we do is save commonly used commands that handle standard tasks, such as reading a keyboard press, displaying text on a screen, or reading a harddrive. All these simple tasks can be saved to a memory chip that runs the moment we press the power button, and continues running as long as the computer is on. So that way, it knows when you press the keyboard for example. But still, no person programs in machine code these days. Instead, we abstract that by making a language that is easier to read and write. Something like C, or Python. So what we do is write code in those languages, and then another program turns that language into the machine code that runs the computer. -------------- TL;DR - Basic tasks that are necessary to get a computer to a point where you can program it are hard coded 1s and 0s that drive the transistors in your processor to a state where you can load more complicated code.", "Before digital computers, there were very advanced analog computers. When they built the first digital computers, they just came up with a way to represent electronically the things that were already being done with gears and levers and cogs and wheels. Read about the amazing machine that was the Mark 1A Fire Control Computer here: URL_0", "It was done by physically plugging in cables. URL_0", "They used straight up binary and machine code until they created assembly which they used to create the higher level stuff.", "old guy here. In college we had assemblers, compilers. After i graduated (1975) I built a MITS ALTAR. My assembler was a pencil and pad of paper. I hand toggled in byte by byte. After a while I built an EPROM board, put a bunch of utilities on it, and had sort of an operating system.", "Lots of long answers, so here's a short one. Programming languages are like regular languages. They are words and symbols that we use to put ideas into writing. Instead of stories, programming languages write recipes for the computer to execute. You can write recipes with a much simpler language; think of how a caveman talks. It's more difficult to express complex ideas, and it takes longer to do, but it can work out to mean the same thing. Assembly is the lowest level programming language, and it corresponds directly to machine instructions. Things like \"Add these two numbers\" and \"Write this register to memory.\" Assembly is still required when writing code for embedded systems, especially for when a microcontroller starts up and needs to set up a C or C++ runtime environment. So even if you are using a higher level language, you are likely going to compile some assembly in there just to get started.", "All of these answers answer your question on a general level, but I would really recommend reading [Code: The Hidden Language of Computer Hardware and Software by Charles Petzold]( URL_0 ) for a deeper understanding. He talks about how the first computers were built and how they were programmed, and he does it in a way that's understandable even to a person that doesn't know a thing about computers.", "almost every answer here fails to answer your question. none of the previous threads posted by mod answered it either. you are not really asking what is the first program, but rather how does the first program interact w/ hardware. how does a computer (hardware) at the end of the day understands code (lines of abstract letters and numbers). it starts w/ CPU, which has built in instructions made by the maker. these are physical circuit that are wired to do specific things. for example, one instruction always add two things together. one instruction is compare two values. one thing is store it to ram. etc. etc. each instruction can be called in sequence to do amazing complex things. this video explains how a CPU is built to understand basic instructions and how to trigger them URL_0 we build software that essentially manipulate the wires of the CPU by sending charges thru wires, and since there are tons of these wires and we are sending these instructions billions times a second, it can do crazy powerful thing, so much so that CPU has evolved to have special instruction built in to do things like decode MP3, or compress video files, or 3D game, etc. when u turn on a cpu, imagine a specific list of instructions are fired in sequence, that has been hard coded into the hardware (storage or firmware depending on the device). this software then allows other things to be executed.", "I think binary is beyond the ELI5 approach. But if you understand that a decimal number can be written in binary like 5 is actually 101, this can correspond to wires with voltage flowing on the '1' wires, and no voltage flowing on the 0's. I can attach these wires to a CIRCUIT. Some smart guys came up with electric circuits that can do mathematical operations. This isn't as magical as it seems, for more details see the bottom of my post. So they make a circuit that takes maybe 16 wires as input, and depending on what the 1st 4 wires do, directs the rest of the current towards different circuits. So if the first 4 wires are 1010 it uses the 'add' circuit. And if it's 1011 it does a subtract (this is just an example). I can do adds and subtractions all day but finding the output of basic math (even really fast) isn't going to change the world. I need to at least store some of the results. So some guys develop a circuit that when you send some current in it stores that value and outputs the last thing stored inside it. This is data storage and I'm not going to explain this part suffice to say it's the magic of transistors. I can do math and store stuff now. Still not very dynamic. What if every operation I send in I label as instruction 1,2,3, etc. And they have their machine (henceforth known as PROCESSOR) go down the list of instructions sequentially. Now I make an operation (circuit) called JUMP (just like add) that moves the Processor back to an operation of my choice. How does the processor move between operations? It stores what the next instruction # should be, so I just change that number. So now instruction 9 could say go back to instruction 2. Now we have loops. We'd also like to be able to make simple decisions like comparing two numbers. This is actually pretty easy; A human would look at each digit individually until he/she found a difference. That's too slow for a computer. The computer just subtracts number1 from number2 and checks if the result is 0. If it's not 0 then clearly num1 and num2 weren't the same. SO Basically... the guys with the punch cards had holes open and closed on the paper. They'd have metal connectors that would fit through the holes in the punch cards which would allow electrical current to flow through some inputs and not others which would turn voltage on wires on and off. They could write rudimentary programs with those and they'd usually receive the output from an actual printer. Those rudimentary programs wrote tools to help write more complicated programs, and this happened over and over until we now have modern computing. Obviously technical progress in memory capacity and cpu speed helped. If the original engineers had the same memory/cpu's we do today they would've done things completely different. Like other disciplines, computing builds on what other giants have done before you. The first \"operating system\" was some guys who wanted to be able to run some common programs instead of loading stuff from tape or punch card every time so they stored the programs in memory and wrote some code they could type a name into and it would run the program with that name. This is not all that OS's do... They're much more complicated now, but that's certainly a part of what they do. Anyway I promised some basic stuff. There are some logic gates that you put on a circuit. They make these with collections of transistors. One is an 'AND' gate. This will output a 1 (voltage on) if both inputs 'a', and 'b' are also 1. AND a|b|output 0|0|0 0|1|0 1|0|0 1|1|1 OR (outputs true if Any input a or b is on) a|b|output 0|0|0 (no inputs on) 0|1|1 (b is on) 1|0|1 (a is on) 1|1|1 XOR ('exclusive or'. Outputs 1 if a or b is 1, but 0 if both are 1. a|b|output 0|0|0 (no inputs on) 0|1|1 (b is on) 1|0|1 (a is on) 1|1|0 (both are on, and xor doesn't like that) Now we'll do a basic 'add' in binary without a carry digit. how about 0 + 1, 1+0, and 1+1... 0 1 1 1 0 1 --+ --+ --+ 1 1 2 ... ok but 2 doesn't exist so like 9+1 in decimal we write 0: 1+1 = 0 * where * is a carry. You'll notice that this lines up with a xor gate. Meaning if both inputs for a given digit spot are true or both false, the output is 0, if only a or b is 1 then the output is 1. So my simple adder takes 2 inputs a and b runs them both through an 'and' gate for the carry output, and a 'xor' gate for the adding. I have two outputs a carry and the result. This gets a little more complicated now.. My next adder needs to account for 3 bits as input.. a, b, and C where C is the carry. This is possible, and it's how math is done in a computer. It's just getting a bit too complicated for reddit now. You chain a bunch of these adders together like say maybe 64 of them... And you can do addition of 64 bit numbers with a simple routing of electrons."], "text_urls": [[], [], ["https://en.wikipedia.org/wiki/Core_rope_memory"], [], [], [], ["https://arstechnica.com/information-technology/2014/03/gears-of-war-when-mechanical-analog-computers-ruled-the-waves/"], ["http://www.columbia.edu/cu/computinghistory/eniac.html"], [], [], [], ["https://www.amazon.com/Code-Language-Computer-Hardware-Software/dp/0735611319"], ["https://www.youtube.com/watch?v=cNN_tTXABUA"], []], "score": [1570, 229, 45, 36, 25, 17, 9, 8, 8, 8, 6, 5, 3, 3]}}, {"q_id": "5ue0lp", "category": "Repost", "title": "How do insects walk on walls?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddtblt5", "ddtblza", "ddtcsng"], "text": ["They do not weigh much. Remember insects also fly. Not weighing much has a lot of advantages. Walls are not smooth, not microscopically. You know this when you put you hand on one for support. The infinitesimal weight of a bug is supported by their equivalent of a toe and fingerhold.", "Van der waals forces. When something slightly positive meets something slightly negative, they will attract. This is occurring in their legs with the wall on a microscopic level. The electrostatic attraction > gravity.", "Things like insects and gecko's tend to have skin on their legs/feet that give it a really large surface area. This allows the van der Waals forces between the wall and the creature to be strong enough to support its weight Below is a close up of a gecko's foot under a microscope. Its similar thing with insects where lots of hairs are present to increase surface area URL_1 Also found a fly's foot for comparison URL_0"], "text_urls": [[], [], ["https://www.eurekalert.org/multimedia/pub/438.php", "http://www.sciencephoto.com/media/379140/view"]], "score": [9, 6, 5]}}, {"q_id": "5ue0vr", "category": "Repost", "title": "Why is everyone on reddit explaining their edits? Even when it is just a typo and they added 1 letter, they write: \"Edit: Typo. I was on a phone\" or something like that.", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddtbslj", "ddtbp09"], "text": ["You can troll people by posting something, waiting for people to reply, then edit your post to something else so the replies no longer mean what they intended. E.g. You post something innocent like \"noodles are the best food\". Someone replies \"I agree\". Then you edit your post to say \"Hitler was right\". Now it looks like the other person is agreeing with that. To combat this, reddit shows a star next to posts that have been edited. So if you see that star, you know that the post could have said something very different originally. So when people edit for legitimate reasons, they say what they edited so you're not left wondering if the post originally said something completely different.", "Because you get the asterix (*) character to let people know you've edited, now if you wrote something that attracted unjustified criticism ( on reddit ? Who'da thunk ?) then the edit might make people think you're not standing by your post (again, remember the audience here) so a harmless edit to correct typos is mentioned."], "text_urls": [[], []], "score": [9, 4]}}, {"q_id": "5uf1id", "category": "Repost", "title": "Why does drinking coffee speed up my bowels?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddth9v5"], "text": ["[Pours 3rd cup this morning] \"looking forward to reading the answers to this in about 30 minutes\""], "text_urls": [[]], "score": [6]}}, {"q_id": "5ui48e", "category": "Repost", "title": "If we replace our layers of skin, why do we still have scars?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddu60op"], "text": ["Skin is actual made of of three layers: - The epidermis, the outermost layer of skin, provides a waterproof barrier and creates our skin tone. - The dermis, beneath the epidermis, contains tough connective tissue, hair follicles, and sweat glands. - The deeper subcutaneous tissue (hypodermis) is made of fat and connective tissue. The epidermis is the part of the skin that gets refreshed often. If you damage that it will just refresh itself, no big deal. The dermis doesn't replace itself, so if you get damage that deep, you will develop scar tissue."], "text_urls": [[]], "score": [3]}}, {"q_id": "5ui6oh", "category": "Repost", "title": "Fast food locations", "title_urls": {"url": []}, "selftext": "Why do some fast food joints place locations right next to each other? For example, next to my neighborhood there is a Burger King, but in the Walmart across the street there is another burger king. Doesn't this cannibalize sales?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddu6q4a", "ddu6k51"], "text": ["It's called [Hotelling's Law]( URL_0 ) and it basically says it's more profitable to split an existing customer base with a competitor than to try and find customers further away from where customers are already proven to be.", "Burger King has looked at the demographics and doesn't feel that it cannibalizes sales enough to justify having only one store. The idea is that people who want Burger King won't go into the Walmart to get it, and people in the Walmart won't leave to go across the street."], "text_urls": [["https://en.wikipedia.org/wiki/Hotelling's_law"], []], "score": [6, 3]}}, {"q_id": "5ujyhg", "category": "Repost", "title": "Why do we get the feeling that we are being watched?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddus0pt"], "text": ["I'm not 100% sure how accurate this is, but I've heard it described as a prey instinct. Basically, your body is taking in more signals than you can consciously interpret, so a lot of them are off loaded to your unconscious. It's a holdover from when we lived in tiny tribes and were in danger of being eaten daily, your subconscious would be on alert for the predators and give you a sense of wrongness if something didn't jibe. So when your mind detects that the information it's collecting doesn't all match up, it gives you this feeling of wrongness or of being watched. A common similar example is nausea while in a car. You see the landscape fly by but you feel like you're stationary. So in response, your body thinks that it ingested poison and needs to throw up the poison. Again, I think this is accurate but it may be totally wrong \u00af\\_(\u30c4)_/\u00af"], "text_urls": [[]], "score": [4]}}, {"q_id": "5uljuf", "category": "Repost", "title": "Why do some countries use daylight savings and is there a real need for us to use it?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dduxi0o", "dduy4hp"], "text": ["Without DST, in London the sun would rise at 3.45am. That \"wastes\" a lot of daylight when most people are asleep. Applying DST \"moves\" an hour of daylight from early morning to the evening, when more people are awake. Originally, the motivation was to reduce the fuel needed for heating and lighting in the evening. You could achieve the same thing by getting up an hour earlier, but changing the clocks gets that effect without changing everyone's schedules.", "Others have already explained the basics, but no one has mentioned the importance of geography yet. The further you travel in distance from the equator and the closer you are in time to the solstices, they greater the difference in length between night and day. Daylight savings time makes perfect sense in Helsinki, Finland and Invercargill, New Zealand, but none at all in Quito, Ecuador, where every day is an equinox."], "text_urls": [[], []], "score": [13, 9]}}, {"q_id": "5ulx5q", "category": "Repost", "title": "Why as a modern society do we worship celebrities and sports entertainers while intellectuals like academics and pilosophers seemed to get a lot more recognition in ancient times?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dduzkln", "ddv1zpz"], "text": ["The short answer is that they didn't. It's just that we don't have that many records of much 'popular' stuff from ancient times.", "I don't think that's true. Sportspeople and entertainers have been popular for millennia. The Roman chariot races have been mentioned. Mozart was highly popular in his time. And so on. And conversely there are some academics that are quite well known today. Stephen Hawking, Brian Cox, Neil DeGrasse Tyson."], "text_urls": [[], []], "score": [10, 5]}}, {"q_id": "5umkan", "category": "Repost", "title": "Could I use a bucket of dirt to ground a small generator? Why or why not?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddv7iuc", "ddv5tz0", "ddv7xly", "ddvgxyg"], "text": ["No. \"Grounding\" is not about having access to some dirt. Grounding is about having access to an object so huge -- usually the planet Earth itself -- that it can absorb unlimited amounts of electricity without becoming noticeably charged.", "No, because the bucket would act as an insulator. If you are really worried about grounding a generator just go to Home Depot, they sell long copper spikes, get a small sledgehammer and pound it into the ground near the generator. Then use a wire clamp, sold right near the copper spike, to connect it up with a piece of 12 gauge or thicker wire. However, for most purposes, you don't need to ground a generator, unless it's a semi permanent installation. I think most generators now have GFCI outlets as standard, which should provide enough protection.", "If you want to use that \"grounding rig\", lose the bucket, put a metal clamp of some kind at the end of the wire (think of jumper cable clamps), and clamp it onto anything metal that is anchored into the ground, like that platform/walkway/railing that the generator is shitting on.", "No, the purpose of the generator ground is to provide a low-resistance circuit from any point where the generator feeds power back to the ground point. Sticking a conductor into a (?plastic?/even metal on grass or dry surface) bucket is not going to serve the purpose."], "text_urls": [[], [], [], []], "score": [75, 9, 7, 4]}}, {"q_id": "5un3c5", "category": "Repost", "title": "If ageing is a biological process, how does time dilation slow it down?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddv9j51"], "text": ["Time dilation changes the rate at which time passes relative to someone else at a different speed. Imagine that you are on a spaceship and you have 10x time dilation relative to Earth. To you, you age normally. If you are 20 now, and live to age 90, then you will experience 70 years of growing and aging. The aging process doesn't really change. But at the end of those 70 years, 700 years will have passed on Earth. The people on earth age at the proper rate for that frame of reference, and you age at the proper rate for yours. So, while 700 years will pass on Earth during this time, you wouldn't experience it as 700 years -- just 70."], "text_urls": [[]], "score": [4]}}, {"q_id": "5unn0w", "category": "Repost", "title": "What is it in music that makes minor notes sound sad and major notes sound happy?", "title_urls": {"url": []}, "selftext": "Is this an intrinsic characteristic of the music- i.e there is something in major/minor notes which evokes a certain response in the brain, or is it more of a cultural response which has been conditioned over time?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddvljua", "ddvfw5b"], "text": ["**Perform a keyword search, you may find good explanations in past threads. You should also consider looking for your question in the FAQ.** This has been asked a ridiculous number of times in the past. Like, possibly more than \"why does mint gum make water feel cold in my mouth?\" URL_0", "Two notes played together sound most pleasing if their frequencies are in a simple ratio. 2:1, 3:2, 4:3, to our ear they blend the best, and give a sense of order and well being. Ratios that blend less well, like 6:5, sound less orderly, and when compared to the simpler ratios, give the impression something is amiss. Music that uses major chords and intervals utilizes the simplest ratios, and sounds more pure. Music that uses the various minor chords sounds more dissonant."], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/search?q=minor+sad+major+happy&amp;restrict_sr=on"], []], "score": [4, 4]}}, {"q_id": "5uq9dy", "category": "Repost", "title": "Why does a PC that has not been reboot in a long time run poorly?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddw0j3y"], "text": ["There are a lot of tiny data from processes before that didn't get deleted and also a lot of defective datas that just take away space or stop programms from working propperly. Like a gear-wheel that looses spikes or gets sand inside. The reebot renews the gear-wheels and makes them run smooth again."], "text_urls": [[]], "score": [3]}}, {"q_id": "5uqjmp", "category": "Repost", "title": "How did popcorn become the standard movie watching snack?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddw4h5f", "ddw4olv"], "text": ["I believe it came from being a cheap food that was incentive for movie goers during the depression.", "im just guessing here but it might be because you can throw it at some blabbermouth in the theater without doing grievous bodily harm"], "text_urls": [[], []], "score": [6, 3]}}, {"q_id": "5urpmv", "category": "Repost", "title": "What is a 'port' (with regard to file sharing) and why are there seemingly tens of thousands to choose from?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddwch1o", "ddwch9v", "ddwd8jh"], "text": ["Your computer has an IP address, which is like the address of an apartment building. It tells the network where to send messages. Within your computer there are multiple programs. Ports are like post boxes in the apartment building. They're there so that when a message comes in from outside the computer it knows which program it should be delivered to. Ports are identified by a field in the headers of TCP and UDP messages that is 16 bits wide. That means there are exactly 2^16 = 65 536 of them. Normally they're represented as the numbers 0-65 535 but we don't really do math with them - they're really just strings of bits we assign to particular programs for a while.", "It's just a more specific way of breaking down where to send a packet. For example, your connecting to 7.12.54.75 over standard internet connection. Well, that IP address is used for many different protocols like web browsing, file sharing, email, encrypted web, etc. So you specify what protocol you're using. Http is port 80. So you're basically saying \"I would like to talk to 7.12.54.75 via standard internet\". You could also do it encrypted via port 443. It's like adding a zip code to an address. It helps route things faster to the right destination, rather than trying multiple different post offices until you get the right one with 123 Main Street.", "Lets say I have a apartment building address. You go to that address but you realise that you were not given the apartment number. Which apartment am I supposed to go to? This is when port numbers come into play. A port number is like a apartment number which tells where to send the packet (or in the analogy, the person) at the given IP address. Lets say I have a apartment number 80 which is running a web sever. Now I know where to go since I have the apartment/port number and now I am able to retrieve/send anything from that specific apartment/server. 192.168.0.1 would be the street name and apartment building. Port 80 would be the apartment number. This is usually displayed as 192.168.0.1:80"], "text_urls": [[], [], []], "score": [15, 3, 3]}}, {"q_id": "5urrv4", "category": "Repost", "title": "How are the kcal of food obtained?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddwgzrv"], "text": ["In a lab setting you use a bomb calorimeter - essentially you burn the substance and measure how much heat is released. Practically, edible food only contains a few different types of digestible components - carbs, proteins, sugars, etc - and the calorie/mass amount for each is well known, so just by knowing the ratio of each in a substance you can fairly easily calculate it's overall caloric value."], "text_urls": [[]], "score": [3]}}, {"q_id": "5us466", "category": "Repost", "title": "Why is CCTV footage almost always blurry and low quality? Considering how much better video technology is", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddwexk3"], "text": ["Video takes up a lot of space and CCTV is always recording, 24 hours a day, 7 days a week. And then I'd rarely ever just 1 camera, so if they were all HD, even a 1TB drive could fill up in less than a day."], "text_urls": [[]], "score": [3]}}, {"q_id": "5utdfr", "category": "Repost", "title": "What does salt do to snails?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddwoizr"], "text": ["Snails and slugs have an outer mucous membrane with water-based slime on the outside, The saltdissolves in this slime, forming a highly concentrated solution of salt. ... As a result, they shrink for loss of moisture, and a pool of salty water forms around them. - Quora"], "text_urls": [[]], "score": [22]}}, {"q_id": "5uttnp", "category": "Repost", "title": "How do some people say the holocaust never happened?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddwsb4v"], "text": ["\u201cGet it all on record now \u2013 get the films \u2013 get the witnesses \u2013 because somewhere down the track of history some bastard will get up and say that this never happened.\u201d \u2013 General Dwight D. Eisenhower, on future Holocaust denial"], "text_urls": [[]], "score": [3]}}, {"q_id": "5utuo5", "category": "Repost", "title": "What is the actual difference between premium fuels and regular ones besides the price.", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddwuv6o", "ddwsjvf", "ddwvxmd", "ddwshn8"], "text": ["It is not really \"premium\" in that sense. It's not a better gas for your car. What it means is the octane rating is higher, meaning it needs more compression in order to explode (which is how car engines work). Luxury cars and \"sporty\" cars use higher octane fuel, but only because their engines are specifically designed for that octane. Putting it in a car designed for regular will do nothing. If you want guaranteed better quality gas, visit a Top Tier station, such as Shell, Chevron, Costco, etc. These stations have submitted to testing to show that they have more detergents than required on all their octane variants, which causes less carbon buildup and other benefits. Now, that doesn't mean gas stations not rated Top Tier aren't as good, it's just that Top Tier stations are guaranteed to be good.", "So... \"Gasoline\" or \"petrol\" is typically measured on its \"octane rating\". Octane is just a hydrocarbon made up of 8 carbons and can be straight, branched or cyclic. However, the combustion properties of n-octane, that is H3C(CH2)6CH3 are well studied. In an engine you are compressing and heating a fuel in the pistons which causes the fuel/air mix in each piston to explode and drive the engine. Pure octane does this at x pressure and y temperature. Higher performance engines may run at higher compressions, and higher temperatures for various reasons. Because of this, n-octane may explode sooner than optimal in the engine cycle. Thus you use a \"higher octane\" fuel, which explodes at a higher temperature/pressure. The \"pre-detonation\" or \"knocking\" can be noticed when low grade fuel is used in engines designed for high octane fuel, however \"normal\" engines will not experience any noticeable difference in performance.", "These Answers suck and in one case just wrong. Here's the correct answer, but in a few parts. 1). The way the engine works is by compressing the gas/air then making it explode. Pushing the piston down. The best time for the explosion to happen is right around the time when the piston is about to go down. [IMAGE]( URL_1 ) 2). Stuff Blows up when it's hot. If you put paper in the oven at ~~451\u00baF~~ Around 500\u00baF it will catch fire. Gas is the same way. There is a temperature which gas will just catch fire. 3). Doing stuff creates heat. If you take a paperclip and bend it over and over again you'll notice where you bend it gets hot. Similarly as car engines do stuff they get hot. Higher performance engines are doing more stuff in a shorter time so they tend to get hotter. Combining 1,2, and 3. You put gas in a performance engine. The engine gets so hot that the gas burns before the piston is ready to move down. Now the engine is pushing up while the explosion is pushing down. This can damage the engine a little (so little it doesn't matter) and wastes energy. So how to stop this. You have to change something in 1,2, or 3. Without 1, the engine doesn't work. You need that motion. 3 cannot be changed because that's just how the universe works. You're left with 2. You can change the temperature at which gas burns. By making the temperture higher then you stop it from burning when it shouldn't. OK now a little older stuff, for the teenager. When do you need 91 octane (premium). It's when the engine is working in such a way that it is really hot. This normally happens with engines running really fast as a lot of heat is created in a short amount of time. So if your car has a redline of maybe 6,000 rpm. It might only need this more expensive fuel for the times you are running over 4,000rpm. Which if you drive like a grandma is never. If you drive like me, that's only for a few seconds after a green light. Super Chargers and Turbo Chargers. These compress air to put more \"Stuff\" into the engine. More air and More gas = More Power. But by compressing stuff you make it hotter. Thus air going into the combustion chamber will be hotter from a turbo/super charger engine then without one. This means turbo/super changer cars are more likely to need a higher octane. Premium spin. There are also some cars which say premium only. This is often times just a marketing ploy. You spent a lot of money on your car so of course it needs the more expensive gas. Not true. In fact ~~most~~ cars now days can sense if you're using Premium gas or Regular. The computers will adjust to prevent this early burn from happening. (Early burn, or predetonation, creates a sound called knock. You have in your car a Knock sensor which listens for this boom) Edit: Article = URL_0", "Higher octane rating means the gas is less likely to explode too early, which can be a problem in engines designed for higher performance. An engine will not benefit from a higher octane rating than is recommended in the owners manual, assuming the other non-octane additives are equal."], "text_urls": [[], [], ["http://www.boiseweekly.com/boise/aaa-us-drivers-wasting-billions-on-premium-gas/Content?oid=3893468", "https://i2.wp.com/mechstuff.com/wp-content/uploads/2015/10/4-stroke-engine.jpg"], []], "score": [117, 74, 15, 5]}}, {"q_id": "5uuf3v", "category": "Repost", "title": "How can the average person prove the earth is round?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddwwuo0", "ddwx1p9", "ddwxt6o", "ddwx03n", "ddwxefg"], "text": ["Stand next to the ocean and watch a tall ship sail over the horizon. If the earth were flat, it'd just recede into the distance forever, but instead the ship seems to disappear from the bottom up. That's how the ancient Greeks knew the Earth is round!", "You know that we have picture of the earth from multiple angles that show it as round. If they can't believe their own eyes they may be too stupid to exist.", "Get a weather balloon from eBay and tie your GoPro to the end of it.. maybe tape your iPhone to it so you can find the contraption when it lands. It would certainly get high enough to begin to see the curvature. People have done it in the past with more elaborate contraptions, but it could easily be done for a few hundred USD. Would it convince them? Probably not.. Some people just want to believe what they want to believe, evidence be damned..", "The sort of proof you can provide is not the sort they will accept. The Earth being round(ish) is the simplest explanation for a wide range of phenomena. Flat earthers jowever, proefer to cook up complex and convoluted explanations for the same thing. Example, they will say you don't fly around the globe, you circle the circumference of a flat earth instead. It's difficult to prove them wrong mostly because the standard proofs rely on some basic physics the flat earthers refuse to accept. I wouldn't get worked up about it.", "I'm not suggesting you actually do this, but this is how you *could* do it: Put a stick in the ground, face north, and measure the angle of the sticks shadow from north, at a particular time. The next day, travel a few miles south, and repeat the same procedure, at the same time. There will be a difference in the angles, and after a bit of thinking you realise that that could only happen on a curved surface, not a flat one. That's how they did it about 2500 years ago."], "text_urls": [[], [], [], [], []], "score": [16, 4, 4, 4, 3]}}, {"q_id": "5uur0m", "category": "Repost", "title": "how do people lose their accents when they sing?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddx0bk6"], "text": ["First, nobody doesn't have an accent. A Midwestern American is what we think of when we hear 'no accent' but really everyone has one. Second, they don't lose their accent when they sing. It's really no different than you singing I'm Gonna Be by the proclaimers; you just adapt your singing to what they sound like. Sometimes it's a bit harder, like going from an American rolling 'r' sound that's made by 'oscillating' the end of your tongue (I can't think of a word) to something more like a French 'r' that's made in your throat. I hope this helps!"], "text_urls": [[]], "score": [3]}}, {"q_id": "5uwqzf", "category": "Repost", "title": "Why do people think the earth is flat? Even people with easy access to internet and information", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddxgz53"], "text": ["Some people are distrustful of authority for a variety of reasons. Predictably, the \"bad authorities\" are usually government, law enforcement, or schoolteachers. However, the distrust can extend to scientists, statisticians, historical records, and other sources of information that support the teachings/laws/policy used by those \"bad authorities\". When these people learn that the world was thought to be flat *until scientists figured out that it was round* they immediately believe that those scientists and/or this history book are lying, and that the people who thought it was flat (before the scientists/historians interfered) must have been correct. The roots of this distrust often come from religion, which can teach information that contradicts scientific evidence. This forces followers to \"pick sides\" and sometimes view scientists as untrustworthy or as liars. When it gets to the point where somebody thinks the Earth is flat, with obvious physical and theoretical proof otherwise, it would usually be classified as a mental illness. Particularly diseases which cause paranoia would be involved."], "text_urls": [[]], "score": [3]}}, {"q_id": "5uxh5n", "category": "Repost", "title": "If women are being paid less than men for what is TRULY the same work, then why aren't companies only hiring women?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddxnpbg", "ddxmz28", "ddxmu01", "ddxml96", "ddxqhme"], "text": ["It's a myth and there is no serious economist on the planet that will perpetuate the tired factoid narrative that women get paid less than a man for the same job - period. And, the simple tidbit of logic you just dropped seems completely lost on the masses who continue to repeat this false narrative. *If* we can assume that all businesses have one central goal, and that goal is to benefit their bottom line (profits). And *if* they could legally get away with paying women 75 cents to a man's dollar (as we are being told women are getting paid). And *IF* those women could get paid that amount while working the same hours as a man and doing the same exact jobs as men while producing the same output as men....then the obvious question is **why would businesses *ever* hire men....ever?** They would be useless and expensive when women can do the same jobs and get the same results. Obviously this is not what is happening. If women are getting paid less than men, it is because... * They are not working the same amount of hours * They are not producing the same amount of output * They are not taking the same risks * They are not working in the same specialized fields (in-demand highly-specialized fields that are harder to fill and demand a higher pay grade). And this is exactly the reason women get paid LESS overall than a man does. Because, if women are in the same field as a man and have the same education, they still end up working less hours than a man...which contributes to getting paid less. Or, as statistics show, the majority of women in the world (the more developed the country, the more true this is by the way - women in less developed countries tend to strive for more technical degrees) opt to obtain degrees in low-paying, less technical fields such as early childhood education or nursing. And, women are significantly less likely to work in highly dangerous jobs that involve high risk of personal injury (either because they are physically incapable or simply not interested...the very fact that something like 90% of all work-place deaths are men is testimony to this...I for one have literally never seen a woman working construction for example). And, as many studies show, there are only about 50% of college-educated women still working after the age of 40 while something like over 90% of college-educated men are still working after 40. So in many instances women just opt out of the work force completely, sometimes for years or decades. So no...women do not get paid less than men for doing the same work. They get paid less than men because they DON'T do the same work or produce the same output.", "This is a growing issue in Iran, funnily enough. University-educated women there find it considerably easier to get work than men because they can legally be paid less. In western countries the wage gap is widely misunderstood (which is not the same as it being a myth, as is often claimed). The question is not \"why do women get paid less for the same work as men\"- the evidence for which is debateable- but \"why do the jobs women gravitate towards pay less\".", "The long and short of it is, the wage gap is crap. Otherwise they'd be doing exactly what you're saying. Men and women make different choices and when you control for those the wage gap disappears. Anyone who pushes this lie are doing a disservice to women because it distracts from real problems that exist.", "Look, any serious economist knows that this wage gap argument is false. If you take the time to actually look at the statistics that have been out for years, it's all across the board. Men are more likely to ask for a raise, least likely to take time off work, and work in deadlier jobs. I lost my amazing boyfriend last week due to his line of work, and we both knew why he was doing it. Money, plus he loved climbing trees. It all comes down to choices. And I'm sorry, but I have only met a few women who actually weld or have went to training schools. Women are more prone to be nurses, vets, or stay at home moms. Which aren't bad things.", "The argument is that an unconscious bias pervades business. Even though women can be hired less expensively than men, people feel that women cannot do as good a job as men. They might not even know they are acting out a bias. I'm just the messenger. Don't hate on me. ;)"], "text_urls": [[], [], [], [], []], "score": [130, 44, 28, 8, 7]}}, {"q_id": "5uxhno", "category": "Repost", "title": "why the moon is visible during the day sometimes", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddxmejy"], "text": ["Because the orbit of the Moon around the Earth (which determines when we can see the Moon) has nothing to do with the rotation of the Earth around its axis (which determines when it's day and night). Earth rotates around its axis once every 24 hours, while the Moon revolves around the Earth at a much slower rate - once every 29.5 days. So sometimes the moon is on the side of Earth's that's away from the Sun (so it is visible at night), while at other times it's on the side of Earth that's closer to the Sun (so it is visible during the day)."], "text_urls": [[]], "score": [3]}}, {"q_id": "5uz168", "category": "Repost", "title": "Why did fully wireless earphones/earbuds take so long to reach the market, when those quirky bluetooth headsets have been around for so long?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddxxoor", "ddy0yd1", "ddxxlir", "ddy9vb8"], "text": ["A big part of the problem was and still is that the buds need to receive a stereo signal at exactly the same time. The phone being in your pocket on one side of your body is enough to throw that off. URL_0", "For a long time, bluetooth audio streaming was not good enough. It would use massive amounts of power consumption in relativity to the range of operation - and would be interfered by lots of things. It wasn't until bluetooth 3 and 4 that it really got better, and added functionality for multiple device connection (ie, connecting your phone via bluetooth to the headset and at the same time your computer or another phone, or even a second pair of headphones) The audio quality still isn't all there, in my opinion. At a rate of 25MB/s, one would think that it would be able to stream at lossless audio quality - but almost every bluetooth audio device i've seen implements some form of audio dithering (reducing the bitrate to make it smaller and easier on the network) before sending it out via bluetooth wireless protocol. *Edit - spelling/grammar*", "The wireless package has been around for quite a while already. The problem was battery life and size. Newer technology allows for long enough battery life to last a day of listening. I had wireless ones 5 or 6 years ago and they only last 4hrs.", "Bluetooth is not \"broadcast\" where the signal is available for anything listening. It is a two-way \"conversation\" which is why you need to \"pair\" your phone/source to your listening device. In short, two Bluetooth devices doing the same thing with the same source at the same time involves at least moderate difficulties beyond making two clones of the same device. As others have mentioned this was not actually possible until later revisions."], "text_urls": [["http://www.businessinsider.com/apple-airpods-delay-wireless-earbuds-technical-issues-2016-12"], [], [], []], "score": [44, 32, 5, 4]}}, {"q_id": "5uz2ko", "category": "Repost", "title": "Why is water transparent, but snow and ice appear to be white?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddxxvnk"], "text": ["For the same reason that the individually transparent hairs of a polar bear look white in the aggregate. You're seeing the result of scattering and absorption of incident light, and the end result for snow is white. The denser the ice however, the more you'll see a deep blue emerge, not unlike the case with liquid water. It's just another case of why the sky is blue, if you know what I mean. See; Rayleigh Scattering. The reason why you get white is that the scattering isn't preferential (until the ice becomes sufficiently dense)."], "text_urls": [[]], "score": [10]}}, {"q_id": "5uzg6j", "category": "Repost", "title": "Are the different shampoos and soap actually different or is it all just a marketing trick?", "title_urls": {"url": []}, "selftext": "if they aren't then is there is any ultimate product that includes everything?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddy74dw", "ddydptm", "ddytskc", "ddyk5cb", "ddyei8u", "ddygazx", "ddyqopi"], "text": ["I assume it's the same for soap, but as a hairdresser I can say that yeah, shampoos and conditioners for different things actually are different, especially if it's a professional product -cheaper products may contain lower quality ingredients and are often much harsher but should still do the job of cleaning your hair. To keep it simple a colour protecting shampoo will be sulfate free, a shampoo for fine hair may be silicone free while one for coarser hair may not be, shampoo for curly hair may be designed so that it won't lather as much, and one for damaged hair will contain more protein than a shampoo that isn't for damaged hair. Designing a \"one size fits all\" product is very difficult since ingredients will contradict each other and using something good for one hair type could be terrible for another. For example, for damaged hair to really get the benefits of a shampoo there would have to be extra protein, and extra protein isn't good for healthy hair and can actually make it brittle since it's too much.", "I recently learned on Reddit that tide is more expensive because the enzymes and ingredients they use are more expensive then most other laundry soap. My son gets bloody noses frequently and tide gets his sheets clean every time. We have tried others and would love to save money on a cheaper detergent, but whatever they use in tide is unique and worth the price.", "I worked for an industrial soap making company, and yes, each of our soaps were designed to lift a specific range of grimes from specific surfaces. There are surfactants which help wet a surface so the soap molecules can cosy up to the grime, chelates which help the molecules disperse the grime into solution, the soap molecules which are double ended. One end sticks to a bit of some kind of dirt, the other end sticks to water. Flush and rip dat dirt outta there. But there are many other things that affect the performance of a detergent like moderating bits, protectors and conditioners for the clean surface, perfumes and colors. Heat improves activity in most chemistry so a temperature range for best results is according to the formulation. Complex stuff. Your mileage may vary.", "Correct me if I'm wrong here: I was always taught shampoos/soaps that boasted about containing vitamins were bullshit because your skin/hair can't absorb them and it's all a marketing ploy. I've tried googling it, but of course all that pops up are beauty blogs talking about vitamin enriched products.", "I bought shampoo at the dollar store and it wouldn't bubble or really spread through my hair.", "I think soaps all use the same detergents, just varying amounts of it. The cheap soaps have mostly fragrance & sulfates, while better soaps contain less sulfates (or none at all, like lye soaps) and more moisturizers. I buy most of my soaps locally, as they are cheap and I have very sensitive skin. You can make your own soap from a kit at Michael's and make your own scent. Better quality soaps are completely worth it and they aren't ridiculously more expensive for a better soap. Shampoo is a completely different story and doing your research is tedious. Cheap brands are mostly water & bubbles.", "Interesting, I just went to a soap making class yesterday. We made cold pressed soap using coconut oil, palm oil, olive oil, lye - this makes the soap, but it needs time to turn into soap. You add whatever color and fragrance to it that you want. My teacher said that Dove and Irish Spring aren't real soaps, but instead fragrance bars. Something about their ingredients. I'm not too sure about the specifics of it, but it was something she was very adamant about. To make cold pressed soap you can use a lot of different things. The oils I mentioned above or fats (like chicken fat) or even butters (like coco butters). There's a whole online recipe guide that helps you pick ingredients for the type of soap you want. Creamy, more lather, for dry skin, etc. So yes there appears to be many differences."], "text_urls": [[], [], [], [], [], [], []], "score": [333, 46, 23, 22, 14, 5, 3]}}, {"q_id": "5uzp4h", "category": "Repost", "title": "Why does adding salt to water make it boil faster?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddy3ahm", "ddy3kja"], "text": ["Adding salt won't make it boil faster. If you have two pots with the same amount of water, and add salt to one, it will heat more slowly because you're heating up the same amount of water, but also heating the salt in the second pot. However, if you were to take one pot with 1Kg of water, and one pot of 20% salt solution totaling 1Kg, the salt water pot will boil faster. That's because it takes more energy to heat up water than it does salt. And the salt water pot has less water than the plain water pot.", "Adding salt to water actually increases the boiling point. About 2 degrees Celsius on the usual. However, salt water will still reach its boiling point before non-salt water. This is because \"pure\" water takes a lot of energy to change temperature. Large heat capacity in other words. When you add salt the water is then no longer \"pure\" and thus has a lesser heat capacity. Now even though the boiling point is greater it takes less energy to raise the temperature."], "text_urls": [[], []], "score": [7, 3]}}, {"q_id": "5v0639", "category": "Repost", "title": "If all of the cells in your body are replace d every ten or so years, how do small blemishes like moles stick around?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddy8mqk"], "text": ["Your skin contains several different types of cells. The skin cells you're thinking of that regenerate and slough off every so often are called keratinocytes. The cells that make up moles/birthmarks are a different cell type called melanocytes. Melanocytes do not get replaced by keratinocytes. As far as cancerous moles go, the skin regeneration is the problem! UV light causes damage to cells by forming abnormal linkages in the DNA. Often this damage can be corrected, but the more UV exposure, the more damage that occurs. If it cannot be corrected, then it is possible that certain regions in the DNA are not read correctly during replication. Some mutations can cause this new cell to become immortal, and it will keep on replicating. This abnormal growth is cancer."], "text_urls": [[]], "score": [12]}}, {"q_id": "5v07mf", "category": "Repost", "title": "What do words fascism and fascist mean?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddy7dad", "ddyajeo", "ddya7vg"], "text": ["Fascism has a few key ingredients. Here's my paraphrasing of some of them: 1. Nationalism 2. Dictatorship/Totalitarianism (it's explicitly anti-Democratic) 3. Economic nationalism, protectionism 4. Violence and oppression used against political opponents and perceived social or political threats (unpopular minorities, for example) 5. Traditional roles and scripts (in whatever culture it starts in; and it only really needs to be the perceived traditions, not actual ones). 6. Cultivating a national paranoia and vigilance against political opponents. Legit fascism and the fascism we use in modern language are a bit different: we use fascist as an insult these days. In general, we call anyone who has different ideas about how to use the national government to achieve some goal a fascist (because they're mustering the national government to \"force\" a certain policy position across the country). This isn't necessarily fascist. But it can be, depending on whether the other factors are present.", "Are you asking what fascism is, or what the word itself means? I'll answer both questions for you. **What fascism is** Fascism is a specific populist political ideology which starts with the premise that war is not only inevitable, but actually desireable: it purges society of the weak and ultimately makes it stronger. A fascist regime rules the country on almost military lines, with a strict hierarchy and the believe that the entire population should be ready to form a fighting force, should the need arise. Government is run by the military and big business, not politicians, and everyone in the country is expected to do their bit. Fascism also strives to make the country self-sufficient, insisting on growing all its own food and manufacturing all its own goods instead of trading with other countries. Fascists also believe that democracy has failed, and the only way to run a state is through a one-party dictatorship. If you take all of that, and add to it violent anti-semitism and a doctrine of racial superiority, you get National Socialism, which is the ideology of Adolf Hitler. That's the basic definition of fascism. In a wider sense, though, people use \"fascist\" to describe any right-wing political ideology; occasionally, some people use the word as an insult to apply to any political movement they disagree with, in much the same way that some people on the other side of the political spectrum will use \"communist\" or \"socialist\" to describe any political movement *they* disagree with. **Where the word \"fascism\" comes from** Originally, it comes from the Latin word \"fasces\", which described [a bundle of wooden rods tied together, sometimes with an axe protruding from it]( URL_0 ). It's thought the bundle of rods represents strength through unity -- a single rod can easily be broken, but tied together they are virtually unbreakable -- while the axe-head represents the power of the Roman magistrate, who could order the death sentence. In 19th century Italy, political organisations called \"fascii\" were formed, which campaigned for some sort of revolution and used the fasces as a symbol of strength. They were scattered about Italy and didn't belong to any one particular part of the political spectrum, until Mussolini brought them all together and gave them direction. This became the Fascist Movement, which gave its name to the political ideology of fascism.", "Imagine a society run like a large corporation with a single CEO and his private army. That is fascism."], "text_urls": [[], ["https://uschs.files.wordpress.com/2011/10/bronze-fasces-detail.jpg"], []], "score": [44, 13, 5]}}, {"q_id": "5v28kl", "category": "Repost", "title": "Can someone explain to me how time dilation works? \ufeff", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddypazv"], "text": ["Imagine that you and your friend are standing 10 feet away from each other, and you're throwing a football back and forth. That football is traveling 10 feet. Now imagine that you're both standing on the wing of an airplane flying through the air. You're still 10 feet apart, and you're throwing a football back and forth. From your point of view, the football is still traveling 10 feet with every throw. But from the point of view of the ground, the football is traveling 10 feet across, and also 10 feet to the side, in the direction that the plane is flying. 10 feet forward, and 10 feet to the left is a hypotenuse of 14 feet. So from your point of view, the football went 10 feet. From the point of view of someone on the ground, the ball went 14 feet. The faster the plane is moving, the larger the disparity. For you, it will always seem like 10 feet, but if you're going near the speed of light, including momentum to the side in the direction the plane is flying, the ball might be traveling *miles* from the point of view of the ground. The distance is relative, depending on where you're seeing it from. Time works the same way, though understanding why takes a lot more than an ELI5."], "text_urls": [[]], "score": [10]}}, {"q_id": "5v2mfa", "category": "Repost", "title": "How do the \"I'm not a robot\" check boxes work", "title_urls": {"url": []}, "selftext": "They are becoming more and more common and i'm happy but how come sometimes it'll have me select signs or extra junk but others nothing", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddysx9d"], "text": ["They are looking for things like how quickly you click the box, if the mouse scrolls or clicks directly on the spot with no discernable movement, and other things that would identify you."], "text_urls": [[]], "score": [13]}}, {"q_id": "5v2pbv", "category": "Repost", "title": "How exactly does a human die when they are exposed to the vacuum of space?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddyt5pb", "ddytc8g"], "text": ["There are a number of different things going on at once, any one of which can ultimately be fatal. The one that is likely to kill you first is the lack of oxygen. You can't hold your breath in space because, with no atmosphere to interact with, the air in your lungs is going to expand rapidly---and if you don't let it out, your lungs will swell and burst and you will die. When you do let it out, it means you will have 5 or 10 seconds before blacking out and dying of lack of oxygen just like on earth. At the same time, the fluid and gasses in your skin are doing the same thing. So the water is evaporating rapidly and turning your exterior into leather. This causes widespread---though not irreversible---damage and will lower your body temperature pretty rapidly. Over your whole body, the pain and heat loss might be enough to put you into shock and kill you. Even if it doesn't, within a few minutes the pressure changes start to impact the balance of gasses in your blood stream. Just as a diver is at risk if they surface too quickly, \"the bends\" starts to become a serious possibility as gas bubbles form in your blood stream and spread to your organs and brain. This, too, can be fatal. And, in the longer term, if you're close enough to the sun you'll eventually cook/roast, and if you're far from the sun you'll eventually (i've seen measures in hours) end up so cold that life can't be sustained. source -- spouse asked whether Chris Pratt's helmet-but-no-space-suit thing would work in real life. Looked at a bunch of websites.", "Well first off you don't explode like you see on TV and movies. Your skin does stretch alot because of the expansion of gases in your body and the lack of pressure in the vacuum of space. Your blood would bubble and circulation would pretty much cease, you'd get horrible sunburn, and ultimately you'd probably just be rendered unconscious and then die after a few agonizing minutes. Oh, also, the water vapor in your lungs would freeze. Just overall a terrible way to die"], "text_urls": [[], []], "score": [13, 4]}}, {"q_id": "5v2rhc", "category": "Repost", "title": "Why can't we throw human rubbish/waste to space?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddythfg"], "text": ["It is extremely expensive to put things in space. Far, far more expensive than it would be to do almost anything else with the garbage. For instance, the goal of [space X is 1,000 dollars per pound]( URL_0 ). The U.S. alone produces about 200 million tons of solid waste a year. That's 400 billion pounds. So just getting the U.S.'s waste into space using the cheapest launch system available (assuming you could launch fast enough, that you have no catastrophic failures that spread garbage over half of a state, etc...) it would cost you 400 trillion dollars. The world's GDP is only 75 trillion."], "text_urls": [["http://www.airspacemag.com/space/is-spacex-changing-the-rocket-equation-132285884/"]], "score": [3]}}, {"q_id": "5v3xzk", "category": "Repost", "title": "When choosing the 'Restart' option on my computer, how does it know how to turn itself on, after being turned off?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddzch1z", "ddz23jm", "ddz9j6z", "ddz2oru", "ddzaaq3", "ddz8w4n", "de0016j", "ddzgut4", "ddzgn2j", "ddzga54", "de04da4", "ddz2tlb", "ddzj2m5", "de028i1"], "text": ["Short answer: it knows you want to restart because up until you actually do the restart it can remember things, including whether you clicked \"shutdown\" or \"restart\". If you tell it to restart, it doesn't actually turn off power - it just wipes the CPU back to a \"clean\" state. Long answer: Your OS will shut down normally (flush writes to disk, park the drives, etc). However, while doing so it will also know whether it's going for a halt or a restart. Once it's finished shutting down, the processor will then send an ACPI command to the motherboard. Again, depending on the shut-down mode you've selected, this will either be a \"shutdown\" command or a \"restart\" command. In the case of a shutdown command, the CPU basically tells the motherboard to turn off the power supply. You wouldn't want your power supply running all the time and consuming power, so normally only a small part of the power supply is turned on while idling. When your motherboard wants power turned on it completes a circuit which tells the power supply to turn on power to the rest of the system. Normally this is when you push the power switch - but modern motherboards can start themselves on a timer, or from a USB event (clicking the mouse), or from a [network command from a remote computer]( URL_0 ). During shut-down, it simply breaks this circuit and the power supply turns off. If it wants to do a restart instead, the CPU executes an instruction which returns everything to the \"default\" state. This clears all the registers, the internal modes (by default every CPU boots up in [an ancient mode]( URL_2 ) that would let it boot very old operating systems), the cache, etc. It's just like the CPU had just had power applied to it. In theory there's no reason you couldn't actually have the system shut off and set a start timer for one second later (since the motherboard can start the system on a timer). It's just easier and faster to reset the CPU. One problematic area can be the other components in your system. The CPU may be wiped clean, but things like your graphics card's frame-buffers will not be. Some applications (particularly games) won't wipe their window buffer before they start - so while they're loading it may display a picture of the URL_1 page you were on before you did the restart. Memory, also, is pretty notorious for having the ability to hold data for much longer than its specs would imply (especially if you hit it with something ultra-cold like liquid nitrogen). On the software side of things - one interesting aspect of modern OSs is they never really \"shut down\". It used to be that when you shut your computer down all the operating system internal code (the kernel) would have to be re-initialized from scratch. This takes a really long time, several seconds even on a fast computer. So modern OSs (Windows 8 and up) will actually write the kernel's state to disk before they shut down. Then they will just load the kernel state from disk rather than set everything up from scratch. This is the \"Fast Boot\" mode, officially called Hybrid Boot because it's a hybrid of a shutdown and a hibernate.", "The computer never fully turns off. So long as the power supply is connected to power, it'll deliver standby power to the motherboard. Once you tell it to restart, it'll shutdown the operating system and then send a reset signal to the motherboard which is, as I described, still powered on.", "The parts of the motherboard which control these things (power control, etc) are aware of whether they are performing a \"hot\" or a \" cold\" start. Cold starts are coming up from no power to the machine, when you physically give the start signal to a powered off machine, and the machine completely initializes itself from nothing. When you perform a soft reset, or a hot reset, you aren't reinitializing the hardware of the machine quite the same way. Some of the management controls just roll back to a certain point of their power-on cycle (we'll call it step 2, whereas step 1 is actually providing power to everything) and kicks the BIOS off and back into your operating system. Because a soft reset like when you do a \"restart\" command never interrupts power to your computer, the management controllers can influence how they turn back on. If you want to think of it in a flowchart kind of way, hitting the power button initiates step 1 of the power on process, and the power controller(s) will provide power to all of the peripheral devices to get them initialized. Step 2 will load firmware/BIOS and run them to get everything on the motherboard synchronized with eachother. A soft reset would skip step 1 and go right to step 2, because it knows step1 is already done. that's a very simplified (to the point of some minor inaccuracies or assumptions based on computer architecture) explanation. Source: am computer engineer for a company that makes embedded processor boards.", "When it's bedtime, how does your body wake up again? Because part of your brain never completely turns off. A computer has a little part inside of it that never completely turns off.", "It doesn't actually turn off. Back in the 90s you would often see a message like \"it is now safe to turn off your computer\" as the computer didn't actually have the ability to power off. It was usually a physical switch. Then some power management features were designed and made standard. This was know as ACPI and one of those features was to do a full shutdown of the machine so that \"it is now safe to turn off\" message was relegated to the past.", "~~I think I have more grounds to answer this fully, since I'm working around issues with restarting.~~ (crossed out, as I am too full of myself) I actually work on components and programs that are involved in restarting computer. It is true, that as long a s computer has power, it's not fully turned off, but it's not the case in 100%. I mean, you have, in fact, more than one computer in your case, and in your motherboard. In modern computer there are at least 3 (4 in business-class motherboards) independent systems, two of them are inside the chipset, one is located within the CPU itself. ~~They have their own memory, operating systems, clocks and are restricted. They are for controlling power distribution (one in CPU), for low-power device management - like SPI BIOS, LPC, I2C, general I/O (second in chipset - and it offloads that control to main CPU after boot), and one controlling interfaces - HSIO, PCI-Express, and couple of other inter-device links, temperatures and power (that one is always active). In business class systems there is one extra system, that is responsible for offline network interface handling, security, and other features that are required for effective management in enterprise environment - this one is also always active.~~ **(this is valid, but too technical, so I crossed it out as not important)** ~~They sip very little power, and generally operate at 30-400 MHz frequency range, and in most cases are single core CPUs.~~ **This is also not important** Back to your original question: When you say 'reset', the firmware (the program that runs directly on the small embedded computers inside your motherboard) inside the chipset just executes a program that says 'shutdown this, this this, and this, cut power to this, and this, and then activate this and this, and go', and then computer boots. Manufacturers have a lot to say about what firmware does while doing reset and power on, especially when they use custom power delivery control systems, like Asus and MSI.", "Lots of really good answers here, but nobody mentions one thing **B**asic **I**nput **O**utput **S**ystem ---- ELI5 The BIOS is the thing that makes it take a few seconds before you get the windows logo. It checks to see whats connected, what the processor is and it's timing, and a couple other things. It can do that because it is a processing system separate from the CPU and the OS. When you tell the computer to restart, the OS tells the BIOS \"Hey we need to restart\". The BIOS then shuts down (not off) everything except the power, and then when everything has reported back \"I'm down\", the BIOS triggers the restart. Remember when you added RAM to the computer that message you got? > System memory changed from 512KB to 640KB. Continue? (Y/n) That was the BIOS. Windows has no idea how much RAM there is, nor most things about the hardware attached to the system, until the BIOS decides to tell it.", "It's kinda like when you go to sleep, you are like the computer restarting. It might look like its turned off, but it isn't all the way turned off. So the computer is really just taking a really short nap.", "Short ELI5 answer: It doesn't turn off when you click restart. It just reloads the operating system.", "Lots of very good replies here. One thing I'd like to add is with the adoption of the ATX form factor/spec gave the operating system the ability to control the power supply. The old AT form factor did not, hence the \"You can now turn off the your computer\" message after the hard drive had parked.", "Restart doesn't actually turn off the computer at all. The OS turns off all of its processes, cleans up its open files, and then when it's done, it sends a signal to the processor that says \"act like you just turned on.\" The PC then goes to the BIOS and starts loading it all over again, which leads to finding the hard disk, reading the master boot sector, and starting up the OS over again.", "When the computer turns on it have a known state. Normally everything is zeroed out as that is the simplest to implement in electronics. From this zeroed out state the CPU will by default start to execute the code at memory location zero, which by default is the BIOS, in non-restricted mode. So to restart the computer the operating system needs to get back to this initial state. So it resets all the devices that needs to be reset, makes sure the BIOS gets back its memory location if that have been changed, etc. Finally it will reset the CPU back to its original boot configuration using a special restart command. The first CPUs did not have this restart command. Instead the OS used an unspecified behavior in the error handling routine that most CPUs would handle by restarting. However nowadays the specification includes a way to reset the CPU back to its initial configuration.", "Minor details that might be interesting more for an ELI25: 1) A restart doesn't just \"wipe the CPU back to 'clean' slate\" on modern x86 computers, but something like that was more common a long time ago. It actually causes the reset signal (an actual wire that goes to a lot of the chips on the motherboard, including the CPU) to be asserted. Think of this as the wire going from zero volts to 5 volts. in practice, though it's more likely asserting reset means going from 3.3V to 0V (inverted and different voltage). This should wipe ALL of those chips to an initial state, so the video buffer issue described by /u/capn_hector isn't really an issue these days. Even so, there are often different levels of reset that are probably invisible to the end user and are utilized for different purposes. 2) While shutting down almost always involves turning off the power supply, that is all abstracted from the CPU/operating system. What the OS actually does is tells the motherboard something like \"put the system into the deepest sleep state\" which happens to be off, but is different than the power being unplugged. Yes, your computer can tell the difference between being turned off with the power button and having the power cable unplugged.", "Your computer shuts down windows first. Your BIOS is still active and your computer can still think about basic things. After windows is shut down your BIOS gets sent a restart command and your PC restarts without losing power. At no point did your computer ever really lose the ability to \"think\"."], "text_urls": [["https://en.wikipedia.org/wiki/Wake-on-LAN", "FreakyMidgets.com", "https://en.wikipedia.org/wiki/Real_mode"], [], [], [], [], [], [], [], [], [], [], [], [], []], "score": [3639, 3431, 890, 549, 334, 70, 22, 16, 13, 7, 6, 5, 4, 3]}}, {"q_id": "5v4a2s", "category": "Repost", "title": "What is that voice in your head", "title_urls": {"url": []}, "selftext": "to which some have just thought \" what voice \" I am referring to *that voice*", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddz9jtj", "ddzcbj2"], "text": ["Well, there's 'hearing voices' and there's your internal monologue. One is some people's stream of consciousness - the way they think - in a verbal way rather than visual way. The other is often a symptom of schizophrenia or a hallucination. Whether these two things are linked is an interesting question. i.e is the fact that I recognise my inner voice as my own thoughts the only thing that differs? I believe this inner voice is (at least one of the things) that Buddhists are trying to escape from by meditating. Which I don't really understand. e.g I was out walking last night and I constantly converse with myself, think of different ideas and mull things as I'm doing that, to the point where I can have covered a large distance without really being aware. To me that's what makes activities like cycling and walking relaxing. Whereas it seems to be that Buddhists believe that ignoring your thoughts and instead trying to focus on being in the moment is important. Perhaps a lot depends upon what kind of thoughts you have. If you're fretting and anxious about things maybe you would want to escape it. I can't help thinking that a lot of epiphanies in maths and physics were reached by this kind of inner conversation - I'm sure most of us are thinking about more mundane things though.", "This wiki article is my favorite that addresses it. URL_0 It basically talks about how there is a part of our brain that appears to be \"speaking\" and a part that \"obeys\" Much like when you are very nervous or unsure and ask yourself \"Am I really going to do this?\" And you truly don't know but then you somehow decide and either do it or don't! It also mentions how this type of inner dialog may have influenced humans view of religion because they literally heard someone telling them what to do. Like the voice of God \"Go find food and water, you can do it\" and as this part of our brain evolved it became more of a part of us and less \"disconnected\" I definitely recommend checking out the link. :) Edit: As I stated in the 1st sentence this is my favorite article that addresses it. I did not state that this is true or scientifically sound. Its interesting and talks about it."], "text_urls": [[], ["https://en.m.wikipedia.org/wiki/Bicameralism_(psychology)"]], "score": [25, 19]}}, {"q_id": "5v4ll4", "category": "Repost", "title": "Why is it a persons natural reaction to grab whichever part of the body has been injured? For example, if you get hit in the back of the head, the first thing you do is grab your head.", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddz5sp3", "ddz88gx"], "text": ["It's the quickest way to protect the injured part. You pull it away from danger and protect it with an uninjured part of the body.", "Had a psychobiology professor explain that since we have way more touch receptors than pain receptors (like 10:1), that grabbing the injured body part is an attempt to overwhelm the pain we are experiencing."], "text_urls": [[], []], "score": [12, 5]}}, {"q_id": "5v4sif", "category": "Repost", "title": "What is the difference between sound waves and electromagnetic waves (light)?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddz7lxs"], "text": ["Sound is a vibration through a medium. It requires something to move through. You hear sound when the vibration reaches your ear. You can feel a sound if it vibrates your body. Electromagnetic radiation is a self propagating electric and magnetic field. Electric fields can make magnetic fields and magnetic fields can make electric fields. These fields can interact with matter (you see light when it hits your eye) but they dont need matter in order to move."], "text_urls": [[]], "score": [3]}}, {"q_id": "5v4xi7", "category": "Repost", "title": "Why does the tray in a microwave rotate?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ddz8gzl"], "text": ["Because there are hot and cooler spots due to the way the microwaves reflect around inside the oven. Rotating the food attempts to distribute the heat in the food more evenly."], "text_urls": [[]], "score": [3]}}, {"q_id": "5v72sk", "category": "Repost", "title": "How do scientists measure the speed of light?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["de02asu", "ddzq4kw"], "text": ["With a rotating prism. Start with two observatories on mountain tops (a good place for observatories) that are far away from each other, but still close enough that they can see each other. Being on mountain tops helps to see over all of the stuff in between them. Measure how far apart the observatories are. Carefully put up a mirror at the far observatory so that the other observatory can see itself in the mirror (very far away, but they have telescopes in observatories for that.) From the near observatory, shine a beam of light at the mirror at the far observatory. Thanks to the mirror, you can see your own beam of light shining back at you from the far observatory. Now take a prism, but not the triangle prism that makes rainbows, no. Use a prism with an even number of sides, like a square or an octagon. This way you can look straight through the prism from one side and out the other. Put the prism in the beam of light. If you hold it perfectly straight, then the light will still shine all of the way to the far observatory and back, but only if it is straight, not crooked. Now spin the prism. Use an electric motor so that you know how fast it is spinning. As the prism spins, when it lines up with the beam of light, a tiny flash of light will go straight through and to the mirror at the far observatory. But by the time the flash of light gets back, the prism will have kept spinning and it won't be lined up with the light beam any more. But if you speed up the motor that is spinning the prism to *just* the right speed, then the little flash of light that gets through the prism and reflects back from the mirror will arrive at exactly the right time to go *back* through the prism when it lines up with the light beam the next time. So if you know how fast the motor spinning the prism is turning, and you know how far away the mirror at the far observatory is, then you know how long it took for the little flash of light to travel that distance. Distance/Time = Speed. And that is how you measure the speed of light.", "Now-a-days we have extremely precise equipment that can measure the time between a photon being sent from a source and it being detected some distance away. Distance over time = velocity (or speed). Back before the invention of fancy lazers and what-not, one of the more famous examples was done by Danish Astronomer Ole R\u00f6mer. He noticed that eclipses on one of Jupiters moons would happen at slightly different times at different points in the year. He used the radius of Earth's orbit and Jupiter's orbit, as well as Earth's position at varying points in the year, to estimate the speed of light (he got 220,000 kilometers per second just 27% off in the 1700s!)."], "text_urls": [[], []], "score": [20, 16]}}, {"q_id": "5v8e4n", "category": "Repost", "title": "Why does the brain not start recording memory for the first few years of life?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["de02o0r", "de0hql6"], "text": ["Your brain saves every single little detail, emotion, color, smell, sound and taste you will ever do starting from day 0 when you're born. It's the greatest and most efficient super computer that exists (today). Problem with that is that certain information is just not relevant for you and you tend to \"forget\" certain things. You might have some slight memories once in a while that you don't even recognize because they are that deep inside your brain. So if there is something really important that happened in your earliest years you would remember (most times that would be some kind of trauma) because the brain filters the importance of information that it gets.", "Your brain is always recording memory- in fact, it lays down more memory in the first few years than it ever will later. Thing is, there's more than one kind of memory. Memory as your question defines refers to events- specific patterns of behaviour in specific locations with specific people. Early on, we have little need for such memory, since we don't have the brain development to make sense of it. Instead, the brain is laying down vast quantities of memory in relation to how your body moves, what faces and people are, what sight and sound is, how words and language work, etc. This type memory isn't linked to specific events, but rather the brain processing other information."], "text_urls": [[], []], "score": [5, 3]}}, {"q_id": "5v8wph", "category": "Repost", "title": "how does a memory card permanently delete a file or Photo? Data is stored somewhere, so does it just vanish with no trace?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["de04t72"], "text": ["It marks the sectors containing the photo as free and deletes the record with the file name from the directory. The data is still there, but not accessible without special software"], "text_urls": [[]], "score": [5]}}, {"q_id": "5vbvtx", "category": "Repost", "title": "Why is it that after 3 years or so laptops become so slow they're almost unusable even if you're just using them for the Internet and nothing huge?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["de0xm5o", "de0stgf", "de15cpv", "de0uofs", "de0uzkn", "de0tnjw", "de0tw1n", "de0u38n", "de12e4r", "de1copk", "de1bv3g", "de196en", "de1c62v"], "text": ["85% Poor maintenance with people cluttering their laptops up with junk and never clearing it. In my experience the older generation does this more, my dad literally had 3 different full install programs to \"test his internet speed\" running all the time. The last 15% is a mix of websites/programs getting updated and modernised and using more resources, with a tiny bit of hardware and software wear and tear depending on useage amounts. Personally I am typing this on an inherited 2011 macbook air that still runs as fast as the day I got it. Open the laptop to typing in 2-3 seconds, full restart in under 60 seconds etc. Never had any issues with it beyond some of my top line keys randomly not working sometimes. Compare that to my mothers macbook from the same period...", "You probably are doing something wrong tbh. You probably accumulated a lot of crap from internet that slow your computer down. You should reformat your computer and reinstall windows. Then protect your computer better, anti-virus, scan, firewall, etc. Maybe you are going on unsafe websites and should limit that. It's normal to reformat your computer from time to time to clean all the stuff that accumulate. It's also normal for computer to slow down over time because new program and operating system need more resources than old ones. But if it become unusable after 3 years either you bought a crap computer, or you don't protect your computer much.", "So many answers but nobody mentioned overheating. Yes, bloated Windows (or other OSes) will get slowed down, but even if you format your computer, it might still be slow. That's because of two reasons. The first is, your hard drive will get slower. Buy an SSD, should be good for the next 5 years. The second, more common one (since as seen in this thread, nobody cares about it) is the fact that your processor starts overheating after years of use. That's not because the processor gets bad or anything, it's because the thermal paste on the processor is old, it dries up, cracks, fills with air bubbles which overheat. If you change the thermal paste on your processor (and graphics unit) your computer should be as good as new. You won't even necessarily notice your computer is overheating. That's because most laptops opt to slow down the processor instead of letting it overheat too much, but in some extreme cases your computer might end up turning off whenever you put too much strain on it. I've seen a case of a core2duo that should be running at 3GHz running at 600 MHz. Change your thermal pastes people!", "The most basic reason for computers \"slowing down\" is that users are asking them to do more work. Imagine you buy a car to drive around town. It's got a top speed of 40mph. Works perfectly. Now you want to take the highway to the next town. The speed limit is 65mph. Your car can't keep up because it wasn't designed to go that fast. It will still drive around town the same as it always did though. Your computer's hardware was designed to run the software of its day. New software (including web browsers and sites) makes use of newer, better hardware available. Much like the car that wasn't designed for highway speeds, your computer is having a hard time keeping up. However, if you want to run the same software you always did, the computer should be able to do that more or less indefinitely. This is the reason you'll often see ancient computers in commercial settings, such as a restaurant or warehouse. They don't need to upgrade the hardware because they never upgrade the software. Those computers can easily last 20+ years if all they do is operate a delivery database or manage shipping and receiving. tl;dr: your computer slows down because it needs to do more work than it can handle.", "Also consider the increased RAM requirement of your web browser as computing power increases. I'm picking on RAM because I've personally noticed my web browsers eating all of mine on occasion. Two factors: - updates to the software make it less efficient by adding more resource-hungry features - as compute and network grows, \"web applications\" grow their resource requirements as well In both cases, the developers don't notice the relatively minor increase in resource use, and by the time it's added up to affect you, they've upgraded their computers. So ideally you'd notice this at 5 rather than 3 years, and you'd not notice it if your \"internet use\" involves one window with one tab on one page at a time. I notice it because I leave my browser open 24/7 with 10-50 tabs, 3 of which are pinned web apps like Gmail and Facebook. So many fucking memory leaks.", "In a general sense, people whom purchase laptops expect them to work the same forever and thus do not partake in any sort of care or maintenance. This means that they will never delete temporary files, uninstall unused programs, or clean out the exhaust or intake pipes and holes with compressed air. Another major problem is that laptop users excessively rely on the lid-closed standby mode, which does not in fact turn off the computer. They will often go weeks or more before properly turning off their laptop. This means two things: one, your hardware is getting unnecessarily strained and two, the components which store voltage-volatile data (data that is erased upon power-down) are never cleared, which only slows things down further. A hard drive will decrease in performance the more information that is stored upon it, especially those slow, 5400 RPM laptop drives. Finally, many laptop owners will accidentally allow their laptop to overheat many times over its lifespan, will drop it, spill things upon it and more. You combine *all of these factors* and on average, the laptop physically and electronically is not nearly as functional as it once was. Edit: forgot another important factor in that almost every laptop at the sub $800 has strong compromises in its design. An old mentor of mine once said that a laptop engineer would sell his grandmother if it meant saving money on the laptop design.", "They don't, they are just like any other computer and last as long as you take care of them. If you've been updating your operating system and installing software down the years then it's not a fair comparison with when you started. Try backing up all your files (remember this bit) the re-installing the operating system.", "Computer repair tech with over 20 years experience here. Laptops and desktops with standard hard drives will slow down after a few years because of several reasons. The main reason is that the drives actually spin slower over time, which will slow down the computer, especially during startup and when running programs. Also, malware software will accumulate causing the internet to load pages more slowly because the malware will be sending info out over the internet while you are trying to browse. Most people have poor upload speeds on their home internet which means that the info being sent out by the malware will clog your bandwidth. Another problem causing slowdowns is hard drive fragmentation. You can run a defrag program, but in my experience it is best for performance to erase the hard drive and completely reinstall windows. If you want a computer that is fast, and will stay fast for more than a few years, invest in a computer with a solid state drive or upgrade your current computer from a standard hard disk drive to a solid state drive. Also, make sure your computer has a cpu with speed above 2.0ghz, or it will be slow as molasses. Many manufacturers sell cheap laptops with low speeds and standard hard drives to keep you coming back every couple years for another cheap laptop. Don't fall victim to the scams. Educate yourself and make a good choice based on specs, not just the lowest price.", "Im still in my 2012 MBA and it's still fan-freaking-tastic. Battery life and standby still rocks.", "Depends on the laptop. If you're talking about older laptops with hard drives then that's your issue. Hard drives are mechanical; the components wear and tear as a result they crawl to a stop. The new SSD laptops will last a VERY long time before becoming slow; even your lifetime. But sometimes it's usually that there's lots of junk processes running built up over the years that crunch valuable CPU time and consume memory; not so common with consumers that only browse the web using chrome. Sure Linux laptops & Apple Macbook's are generally better because the OS is better made (Read Patch vs. Core; basically about how Unix programmers fixed core issues while Windows developers patch n patched n patched'ed over crap)", "After three years time, there's only a few reasonable causes I can think of for a severe loss of usability in a computer. 1) The computer is cheap, and is using hardware that is already several years out of date at the time of purchase (I'm looking at you, Intel Celeron and Pentium). As far as a solution, well, don't buy dirt cheap laptops. The \"Diminishing Returns Curve of Computer Hardware\" is a term I like to throw around. Basically, it's a graph of dollars spent v. performance yield of the computer. Despite somewhat popular belief, it is curved on both ends. Spend more than, say, $800, you will start to see less performance gain per dollar, and the strength of this effect gets stronger and stronger as you keep spending more money. Spend less than, say, $300, you will start to see *more performance loss* per dollar taken off. Those dollar amounts are rough and not true values to live by, but the point is there is a middle ground. 2) Very poor treatment of the operating system, be it Windows, OSX or a Linux distribution. This kind of piggy backs on #1, as newer hardware can better cope with the abuse, but if you have a ton of junky programs on your computer, you will find it is going to run quite poorly. If this is the case, some single use programs (for Windows systems) I like are [Junkware Removal Tool] ( URL_0 ) and [adwcleaner] ( URL_2 ). I hesitate to say antivirus will help, because those are targeting malicious software that is actually trying to steal your information or damage your system, and junkware isn't always malicious. That said, antivirus is always a good idea because malware can end up causing system slowdowns. Some antivirus names I am familiar with and haven't had a bad time with are Malwarebytes, Kaspersky, Avast and Sophos. 3) A bit of a stretch, but a failing storage device in a computer is extremely disruptive to system performance. Not to mention, your data will be in danger if you don't back it up to another device before it fully fails. There are tools, such as [Piriform's Speccy] ( URL_1 ) that can tell you what is called the \"SMART status\" of your storage devices. Basically, SMART is a system that makes your storage device self aware of it's own health. If it's not \"Good\" or \"Verified\" or some other synonym of the word \"Good\", then something is wrong with the device and you should back up your data before it inevitably fails. edit: formatting didn't work as magically as I wanted it to", "I've had the same laptop for about 8 years. I put a new Linux install on maybe once every six months. Runs like a dream.", "A lot of really great insight and advice going around here, but I've yet to see a pretty obvious reason. Three years is a long time for a computer of any kind to go without hardware upgrades as well as reformatting. Heck, most people only keep their cell phones for 2 years or less. That all said, I agree with the others here saying it's a little strange that your laptop becomes basically unusable after only 3 years of internet browsing. Almost certainly a maintenance issue. Periodically reformat your HDD with a fresh install of your chosen OS. Don't ever use your laptop on a fabric surface to avoid overheating internal components. If you carry your laptop around a lot in a case or backpack, be gentle with it. If you have a tech friend have them show you how to use Event Viewer and Resource Monitor to better diagnose where your problems are originating. Computers are like cars - if you don't take care of them they'll eventually break down."], "text_urls": [[], [], [], [], [], [], [], [], [], [], ["https://www.malwarebytes.com/junkwareremovaltool/", "https://www.piriform.com/speccy", "https://www.malwarebytes.com/adwcleaner/"], [], []], "score": [274, 240, 65, 35, 22, 8, 7, 5, 4, 4, 4, 3, 3]}}, {"q_id": "5vdh7q", "category": "Repost", "title": "Why do people invest in US government bonds if they are in trillions of dollars of debt?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["de1bbj1", "de1604r", "de16jbv", "de1b3g1", "de17ktz", "de1de4z", "de163qc", "de1nww2", "de1lz1x", "de1a6nk", "de18tp6"], "text": ["Imagine that you have founded a new Business trying to create a new Factory to produce Widgets. You don't have the cash on hand to build that Factory, and you don't have the Credit History to borrow it all from one place. You *could* issue Stock, but that would reduce your control over the business significantly. Instead, you decide that you will issue Bonds. Bonds are *promissory notes*, basically an IOU. A Bond is a promise that you will pay whoever legally owns it back what they bought it for, plus a certain amount of interest, on or after a certain date. Bonds are *much smaller* than Loans. The big benefit to Bonds over a Loan is that Creditors get to choose how much of a risk they're taking on you. Also, if you want, you can offer to buy back Bonds early for *less* than they're going to be worth if people hold onto them. Bonds don't work like Loans or like Credit, which are the two types of Debt that most Americans deal with every day. You know *exactly* what you're going to owe, and *exactly* when you're going to owe it. If someone forgets to redeem their bond, they **will not** continue to accumulate interest past the date it could be redeemed. Bonds \"growing\" past their Redemption Date is a Myth, and I blame Sitcoms for it. The present it as if it were compound interest, when it's really just the Bond's Terms allowing for its value at the date of redemption to be adjusted for Inflation. It should be noted that some Bonds *do* expire after a reasonable period of time, for the same reason that Gift Cards expire after a reasonable period of time. It's to keep the Accounting Ledgers from accumulating *countless* entries that will never be redeemed, because the Bond has been forgotten. Government Bonds *usually* don't include an expiration date, though. --- The United States Government *looks* like it has an unmanageable amount of Debt. Indeed, were it a Line of Credit (Credit Card) or a Loan with a reasonable interest rate... I'd doubt that we would ever be able to pay it off. Compound Interest would *murder us*. Fortunately, our government isn't **stupid** enough to go with Credit or Loans when it comes to the National Debt. We know when *every* Bond that has been issued will be due and how much they will be worth; and we have planned accordingly. The United States pays off *every* Bond that someone wants to Redeem. In its entire history, the United States Treasury has never failed to pay a Bond that it has issued. There aren't many Countries that can say that, and that's why US Treasury Bonds are seen as a safe investment. The Debt *will* be paid off as it comes due. It has *always* been paid of exactly when it comes due. The United States is nowhere near being in a position where we can't pay off our Debts as they come due. You'll know when we get near that position, because the Head of the Federal Reserve and the Treasury Secretary will appear on all the News Channels talking about the situation. --- Interesting Side Notes: **We owe most of the Debt to ourselves.** ~$5.54 Trillion Dollars of our Debt is owed to Agencies within the United States Federal Government. I've checked, and there is no typo in the sentence that preceded this one. Almost *a third* of the Debt is owed to the US Federal Government. ~$2.463 Trillion Dollars of our Debt is owed to the United States Federal Reserve Bank. The Feds alone hold ~$8 Trillion Dollars of our National Debt, if you count the Reserve Bank (which we should, since Federal Appointees make up half of its Board). That's kinda interesting, considering how Foreign Governments only hold ~$6.281 Trillion Dollars. Yep, that's right. The US Federal Government owes more money *to itself* than it does to all Foreign Governments *combined*. You'll notice that there's a lot of debt missing there, though. That's what the Feds owe to *American Citizens*, and the lower levels of Government (State, County, and Municipal Governments). Most of it is held in Mutual Funds, Pension Funds, and so on. So... yeah. Considering how the Social Security Fund handles its Investment Mandate by buying Treasury Bonds, it's fair to assume that the Average American's Retirement Fund is mostly made out of US Federal Debt. **The Countries that own our Debt might surprise you.** There are certain segments of the Media that like to talk about China \"coming over to collect.\" However, the biggest Foreign Holder of American Debt is not China, it's Japan... which doesn't have the capacity to launch an invasion across the Pacific (running a supply-line across an ocean isn't easy). The most current list of Debt Holders that I could find is the following: 1. Japan 2. China 3. The United Kingdom 4. *Ireland* 5. The Cayman Isles Japan and The United Kingdom are both major players in International Banking. China has the second-largest Exporting Economy in the world, behind the United States by a fairly large margin thanks to the Trade Sanctions other countries have leveled against them due to their labor practices. The holdings in Ireland and The Cayman Isles are probably Tax Shelters. Those countries get used for Tax Dodging *a lot*. Oh, yeah... didn't mention that, did I? The amount we owe to these \"Foreign Nations\" aren't just owed to their governments. We combine Debt held by their Governments with Debt held by their Citizens. As we've already established: US Treasury Bonds are a ludicrously safe investment, so they get *bought* and *resold* on the International Market. I could literally buy one from London, if I wanted to, and own it as an American Citizen. Most Debt owed to Japan and the UK is actually owed to Banks and Businesses there. The Debt owed to China is split between their Government and their Corporations... which is a blurry line due to their weird Capitalism-Communism Hybrid system. **Tl;Dr:** We aren't anywhere close to defaulting on our Debt, and most of it is owed to ourselves. **Edit**: Removing a few things that were vaguely political. Also, something that was factually inaccurate but irrelevant to the point.", "> US government bonds are seen as a safe investment aren't they? Yes, they are. > Why is this the case? Because the US is a $17,000,000,000,000 economy with strong stable government and hasn't defaulted on its sovereign debt in its entire history. > It seems like this will never be paid... They are paid off everyday. The US has been continually paying off and issuing new debt for decades (if not longer).", "The US has hundreds of years of history of paying bonds off exactly on time. They've never missed a payment so you can be sure that they won't miss yours.", "Basically if the US defaults on it's debt to the point that it can't pay your bonds back then there are much much bigger issues and most of your other investments are likely in trouble too.", "Because even though the aggregated debt is enormous, the U.S. still has a strong likelihood of paying back the loans. For now at least. You will find that although U.S. public debt is 80% of its GDP (in the most recent year sampled, using the leftmost metric on the Wikipedia chart), this is only 25th-highest among the countries that provided numbers. Here are some notable countries that have higher percentages: \u2022 Japan (174%) \u2022 Greece (158%) \u2022 Zimbabwe (129%) \u2022 Portugal (116%) \u2022 Italy (115%) \u2022 Ireland (110%) \u2022 Singapore (110%) \u2022 Belgium (91%) \u2022 UK (90%) \u2022 France (87%) In theory (ignoring the governmental & legal idiosyncrasies between these countries), the economies of these countries are less likely to support debt reductions than the United States economy. (Note that the World Average for this metric is 64%. There are also a few countries with negative-debt, such as Norway and Saudi Arabia.)", "I'd add that the debt is in dollars. The US government CAN create any number of dollars at any time to pay off its debts. That's not how it's done because that causes other problems, but it COULD be done. Therefore no lender to the US government is likely to ever not be paid.", "Because the US government bonds are the safest investment on the planet. The US has never defaulted on its debt when it has come due in its history and the interest is at a set locked in rate when you purchase the bond.", "Many people don't quite put this together, but U.S. government bonds ARE the debt. The reason the debt is so high is not because the U.S. spends too much and must therefore seek out lenders, cap in hand. Just the opposite--investors all over the world simply love buying the bonds, because they're such a stable investment. There's no shortage of people willing to buy bonds (i.e., people willing to lend the U.S. money for cheap). So the government supplies what the buyers want--bonds. The U.S. has never defaulted on a loan, and every bond issued to date has been paid in full. If, magically, the U.S. national debt were to be paid off instantly, in full, it would rise up again. Because people want the bonds.", "The simplest explanation is because they have never missed a \"payment.\" Any bond is just ownership of a piece of debt. Owning the debt entitles you to payment based on the terms of the bond, which consists of (a)repayment of your original purchase amount after a set amount of time and (b)interest (called \"yield\"), paid out periodically between now and then. The interest rate reflects the level of risk that the bond may not be repaid. US Treasury bonds have very low yield, due to the fact that they are considered to be among the safest, if not the very safest, investments on planet earth. The US has always returned on and repaid their bonds, exactly as promised. By contrast, a country like, say, Greece, would have a very high yield on their government debt, because they have defaulted in the past, and the likelihood they will default again in the future is very high.", "Just because there is a high dollar amount of debt isn't a source of concern if there is the ability to pay it back, and the U.S. has always been able to pay its debts. New debts are issued and old debts are paid and retired on a daily basis.", "The debt isn't something that has to be paid off all at once; as long as the government makes sure to pay back each bond once it reaches its point of maturity (which they have never failed to do, ever), they're golden. At this point the U.S debt is an arbitrary number which has little meaning if they keep increasing it by a steady amount"], "text_urls": [[], [], [], [], [], [], [], [], [], [], []], "score": [1560, 142, 39, 21, 15, 6, 5, 4, 4, 3, 3]}}, {"q_id": "5vf24p", "category": "Repost", "title": "Why does the world need money?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["de1ktza", "de1kjlv", "de1jvqi", "de1l3tc"], "text": ["Because without money, trading usually hits a dead end. Like in this example. > \"Hey Roof Guy, my roof is broken. Can I trade you two chickens to fix my roof?\" > \"Sure thing, Chicken Dude.\" **Two weeks later** > \"Hey Chicken Dude, I'm really hungry. Can I have some more chickens?\" > \"I don't have anything that needs fixing, go away Roof Guy.\" Once you add money into the mix, Roof Guy doesn't have to starve. Each of us only has so many skills or goods to trade; money allows us to turn that skill into value that can be used now or later, even if our services aren't needed.", "It's an easy way to make an indirect trade. Rather than be paid in potatoes or grain or whatever the employer or tradesman had on hand, it's much easier to be paid in a trustworthy currency and then exchange that for whatever it is you really need or want, whenever you happen to need it.", "Because after many tries and experiments, people found that it was really, really inconvenient to buy a water buffalo with skittles. Just as an example.", "Probably too much of an answer, but this (very long) quote from the fictional character Francisco D'Anconia in the Book Atlas Shrugged (1957) addresses the value of money. \u201cSo you think that money is the root of all evil?\u201d said Francisco d\u2019Anconia. \u201cHave you ever asked what is the root of money? Money is a tool of exchange, which can\u2019t exist unless there are goods produced and men able to produce them. Money is the material shape of the principle that men who wish to deal with one another must deal by trade and give value for value. Money is not the tool of the moochers, who claim your product by tears, or of the looters, who take it from you by force. Money is made possible only by the men who produce. Is this what you consider evil? \u201cWhen you accept money in payment for your effort, you do so only on the conviction that you will exchange it for the product of the effort of others. It is not the moochers or the looters who give value to money. Not an ocean of tears not all the guns in the world can transform those pieces of paper in your wallet into the bread you will need to survive tomorrow. Those pieces of paper, which should have been gold, are a token of honor\u2013your claim upon the energy of the men who produce. Your wallet is your statement of hope that somewhere in the world around you there are men who will not default on that moral principle which is the root of money, Is this what you consider evil?\""], "text_urls": [[], [], [], []], "score": [13, 6, 4, 3]}}, {"q_id": "5vfl8q", "category": "Repost", "title": "What do pharmacists do? Doctors write the scripts, big pharma manufactures the drugs, what's the pharmacist do other than select a bottle from the shelf and dole out the pills?", "title_urls": {"url": []}, "selftext": "Genuinely interested, sorry for belittling an entire profession.", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["de1otqc", "de1zzqv", "de2gbmi", "de1p2a3", "de1oshn", "de1riqa", "de2a91q", "de1oubz", "de1pd4c", "de2eom6"], "text": ["A pharmacist is basically a specialist in medication, meaning they probably know more about medicines than some medical practitioners. They do so much more than dispense medicine, they also offer consults on use and dosage. They are also the last line of defence when it comes to drug interactions, especially when a patient is treated by numerous practitioners. And last but not least, they deserve a medal for being able to translate a practitioner's handwriting.", "I'm a nurse in a hospital, and pharmacists do a lot. They dose medication for patients whose liver or kidneys aren't functioning properly (meaning they're not able to clear the meds out of their system like a usual person would) and dose especially toxic medicines based on lab results. Lots of meds my patients get come with a physician order stating \"Pharmacy to dose\" bc the pharmacists are experts in how the drug works in and is processed by the body. They figure out alternate ways of getting a medicine into a patient when the usual ways aren't working, like when the patient needs a pill but chokes on everything they try to swallow, or need an IV drug but don't have an IV for whatever reason, because they have the knowledge to compare different methods if the same drug or alternate drugs that can go in a different way. They also double check medicine compatibility and dosage, which seems like a computer could do, but gets complicated when you have patients on many drugs being used in non-standard dosages for different conditions. They also physically mix the drugs, which requires a lot of knowledge of the chemistry of the body in order to ensure the med is safe to give and being given correctly. They're also in charge of a lot of the facets of making sure med errors don't happen. Pharmacists are experts on the drugs, so the doctor can focus on treating the patient, instead of reinventing the wheel.", "Canadian retail pharmacist here: - My main job is to \"check\" prescriptions that come my way to make sure they're accurate. My assistant 99 times out of a 100 is the one who types the prescription and counts the actual pills. Common physical things I catch are wrong doses (2.5 mg instead of 25mg), wrong drugs (doxycycline-an antibiotic to be avoided in pregnancy vs doxylamine a morning sickness pill) and illegal prescriptions (narcotic forgeries). Some trained technicians can perform this step but IMO the above are easier to spot with pharmacist training. - Check prescriptions for \"drug related problems\" such as interactions. In my experience, pharmacists tend to be overly cautious people. So yes, we will run certain drug combos through our computer, or glance at the patient hand-out to \"double check\" ourselves-this is a good thing. Sometimes I need to remind myself of a drug I haven't seen in a long time! Once we get the information we can interpret its severity quickly, which a lay person could not. As others have pointed out, there are tons of interactions that get \"flagged\" and a pharmacist is able to determine which is important based on the individual patient. For example, I have prevented very serious problems by contacting doctors over a dangerously high dose of antibiotics in a child, or a drug interaction that was only meaningful because it was for a frail elderly lady. This is a pharmacist's job-doctors are trained for diagnosis, not drug interactions. - I help people understand their medications. For example, the man who just had a heart attack and is leaving the hospital overwhelmed with a pile of meds. Without me they usually will stop taking one or two (or go back to smoking, or try a over-the-counter snake oil instead) and be at risk for a second heart attack. I sit down with them, and based on their personal needs talk about the risks vs benefits of the meds. Then I call them in a few days and follow up, making sure they've made an appointment with their family doctor. Or, I do a medication reconciliation with an elderly woman who has too many medications with side effects, and work with her doctor to see if some can be stopped. - I answer people's questions 24 hours a day with more accuracy and clarity than google. (We are open extended hours) For example- its 2 AM and someone comes in with a sick child: what medication do they use? Should they go to the ER? This saves the healthcare system (or you, if you're American) money. - I give flu shots which saves the government money as they pay us less than doctors, and the patient time. I also give other vaccinations, such as hepatitis B, so if you're going to Mexico you can be protected without the need for extra doctor visits. - I prescribe certain medications for minor conditions, again saving the healthcare system money and the patient time. - I can change some prescriptions with the patient's ok, for example if a product isn't available or something is missing from the prescription. - I specialty make a lot of drugs, for example certain seizure medication for children isn't sold in liquid form- I will make this for you at 3AM when you realize you are completely out of doses for your kid. - I dispense and monitor methadone, helping former addicts come off narcotics and re-integrate back in society (in partnership with their awesome nurses.) - I deal with insurance agencies to try to get medications covered, sometimes contacting your doctor to see if an alternate drug would be acceptable. - I consult on the phone with doctors, nurses, homecare workers etc deciding what course of action would be in the best interest of the patient. - I use math calculations to be able to figure out the correct dose of things like Tylenol for infants too small to be listed on the box, again at 2 AM. Or help someone self-adjust their insulin. - I get annoyed when someone is yelling at me from across the counter wondering why their order isn't done yet, asking what the heck I do all day. ;) TL;DR: Pharmacist's are drug therapy experts who can help you take charge of your health and decide if a certain medication is right for you. Like any profession there are a few dumb/lazy ones out there- but most of us work our butts off to keep you safe!", "Pharmacists are experts in medications, even more so that doctors. Doctors are responsible for a lot of information and decisions, done quickly. Under those circumstances, it can be easy to order medications that are incompatible in the same patient. One of their chief responsibilities is to make sure medication orders make sense, drug interactions are minimized, doses are appropriate, and so on. That makes it sound like they're only purpose is to doublecheck Dr.'s work, but in truth they tend to have a much more in-depth knowledge of the field of medications, their effects, and their doses. There's a lot more to it than that. The stuff you see them doing is counting to make sure the right number of pills get into your prescription. It gets much more difficult when there are multiple prescriptions on the same patient. Also sometimes doctors need doses that don't exist in pill form. In these cases it's up to the pharmacist to make a new pills, or capsules, or syrup liquids, in order to make the doses precise. For example, let's say there is an antibiotic that is only available in 200 mg tablets. A doctor needs syrup made up to give to a baby that has 75 mg in 1 teaspoon. A pharmacist has the technical expertise and know how to mix the syrup with the pills that are available. They really are an indispensable part of the care team.", "Makes sure that your Doctor isn't asleep or overworked by checking for interactions. Providing a ton of free advice about what cream for this rash or that minor condition you may have. Teaching about generics which might save you money. Calling your Doc and working out an alternative prescription which IS covered under your health insurance.", "Pharmacists assume I'm an idiot and view all of my prescriptions as pending death certificates for my patients. And, I can't be more pleased about it. Everyone makes mistakes. Even doctors. Pharmacists have saved my patients from my mistakes many times.", "My pharmacist has saved my life a couple of times. I take a medication every day that doesn't play nicely with other drugs. When my doctor prescribes me something else like an antibiotic or an anti-inflammatory, even though she always checks her computer for interaction issues with my main meds, I still always double-check with the pharmacist. More than a few times he's had to call my doctor and say \"oh hell no\" and recommend a different drug. His knowledge of medications, uses and interactions is on a different level from my doctor's. Her focus is in diagnosis. So the two work together in concert very well.", "Pharmacy technician here, They check that the prescription has been written correctly, that the patient can take the drug, i.e. is not allergic to something in it or that any other medications they take can be taken with the drug, and that the dispensed drug is correct. They also answer any questions that the patient has about the medication", "Typically they counsel patients on proper dosage, potential side effects, any adverse issues when used in conjunction with other drugs, and recommend generics when available.", "I have to say that my pharmacist is a great guy. I get multiple scripts. Some are mail order through the Caremark, which CVS pharmacy is a part of. Carmark CONSTANTLY fucks up my orders. It becomes a big deal when I ordered my daughter's insulin 2 weeks ago and we are down to the last of it, and the mail order assholes still say it will be another 2 days. Sure I can get it at the CVS directly but it will cost $250 for one vial. This is when Dave, the pharmacist of the year, takes over. He called Carmark, chewed them out, got them to cover the cost of the temp vial due to it being their screw up, and there was no charge. Caremark has fucked up about 90% of any mail order scripts I have ordered. I have gone weeks without my blood pressure meds due to their screw ups. It is one thing to deal with high blood pressure, but quite another when your young kid is T1 diabetic. Thanks Dave! You are awesome and make my life easier."], "text_urls": [[], [], [], [], [], [], [], [], [], []], "score": [355, 46, 34, 33, 15, 12, 6, 5, 4, 3]}}, {"q_id": "5vfq4q", "category": "Repost", "title": "Why do novels always seem to have 2-3 extra blank pages in the back?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["de1poso"], "text": ["Commercial printing is done the same way that a home printer does, one page at a time. They print whole sheets with a bunch of pages at a time then cut and bind them together in bundles. If your book doesn't neatly match the bundle size, you have blank pages & it's easier to leave them than to remove them."], "text_urls": [[]], "score": [5]}}, {"q_id": "5vggr9", "category": "Repost", "title": "why do some commercials get cut off half a second into the content and skip to another commercial?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["de1wu4x"], "text": ["The commercial that gets skipped to is usually inserted by the local station. The station is given a list of timeslots for commercials and they program their video switcher & playback system to switch to the local commercial at the appropriate time. Somewhere along the way, though, there may be a clock that's not quite synchronized or someone didn't tag a commercial with the exact right length, or in some older systems, someone has to push the \"take\" button on the router manually at the right time."], "text_urls": [[]], "score": [3]}}, {"q_id": "5viovo", "category": "Repost", "title": "How do islands float?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["de2ceaz"], "text": ["The thing in the video is basically a *boat*, not an island. Islands are connected to the ground under the water."], "text_urls": [[]], "score": [4]}}, {"q_id": "5vjl2v", "category": "Repost", "title": "Whats the big deal with the new AMD Ryzen CPU?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["de2mqso", "de2jkp2", "de2nhjk"], "text": ["As stated on the comment above, Intel thoroughly dominated the desktop CPU market for way too long. Why you may ask? Let's rewind back to 2011, Intel just released their 2nd gen of core i3/i5/i7 CPUs and AMD needed to respond. AMD's response to the market is their Bulldozer line of CPUs, Bulldozer failed because it was made with too much emphasis on multi-core performance and as a result, Bulldozer CPU's single core performance were horrible. Combine that with the fact that most programs at the time did not support multi-core CPUs, AMD gave way for Intel. Fast forward to 2014 and Intel knew that AMD weren't a threat anymore, as a result Intel gotten lazy at generational improvements, causing them to \"milk\" the CPU market for time to come. Fast forward to the present and AMD needs to respond badly, and Zen is their last ditch effort at it. Zen was made with single core performance in mind and as a result, Zen is reported to have a 52% improvement in single core performance over Bulldozer, enough to put them in place with 5th generation core i3/i5/i7 CPUs. AMD needs Zen to succeed badly, because if they fail to meet their quota, AMD may never compete in the desktop CPU market ever again. We need Zen to succeed badly, not because of AMD's sake, but for the sake of competition in the CPU market.", "basiclly intel has dominated amd for the past several years while amd has hade nothing much to combat it. Granted amd does have the budget friendly FX series which has the bottom of the cpu market. The new Ryzen line offers products that match and or beat intels line up and in all having a lower cost to them", "An article I read earlier showed performance numbers for the $400 Ryzen 1700x matching the performance of the $1100 i7 6900k. For $500, you can get a Ryzen 1800x that BEATS that 6900k. If these are actual, un-altered numbers, this is huge for not only AMD and the PC world, but will really lead to some innovations in CPU technology in the coming years because of new-found competition from AMD."], "text_urls": [[], [], []], "score": [13, 7, 5]}}, {"q_id": "5vnf2c", "category": "Repost", "title": "Why does food stored in cans stay good for so long?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["de3enbd", "de3thlf", "de3sm1q", "de3nh05", "de3rex8", "de3roy2", "de3s53t", "de3sh7e", "de3sz71", "de3r3mk", "de3t989"], "text": ["Because the food processing company (or home food preservationist) carefully kills all the germs inside the can either immediately before or immediately after it's sealed. In home canning (which, if there were any justice in the world, would be called home jarring, because nobody uses metal cans at home, but there ain't no justice), you put your food- tomatoes, asparagus, jam, whatever- into a jar, seal up the jar, and then boil the jar, whole, for several minutes, until the jar and everything in it has been at boiling temperatures, killing any germs that might have been inside. Afterwards, there are no (live) germs inside to spoil the food, and since the jar is sealed, no germs from outside can get in.", "Food is usually heated prior to being filled into cans, but it doesn't have to be. Once the can is filled it is sealed, then it is heat processed. The severity of the heat process usually depends on the pH of the food. Below a pH of 4.6 it can be pasteurised - given a heating process at 100\u00b0C or less. Foods above a pH of 4.6 are considered \"low acid\" foods. Commercially canned low acid foods are heated to an equivalent of 121\u00b0C or 250\u00b0F to the centre of the food, for a minimum of 3 minutes (though usually longer). Because it takes a long time to heat the right through the food it will often take about an hour to process something like a can of baked beans at 121\u00b0C. This is done in a pressurised vessel called a retort. The pressure prevents the can from bursting or distorting and can allow the use of water for processing (though steam is also commonly used for heating the cans). This temperature and time combination is enough to kill the highly heat resistant spores of clostridium botulinum. If any survive the process they can reproduce and kill the consumer of the food. The legal minimum processing time for a canned food is designed to produce \"12 log\" reduction in the number of these spores, so if there's a single spore in the very middle of a can it'll have a 1 in 10^12 chance of surviving. Virtually zero. This bacterium produces botulinum toxin (botox) the most lethal neurotoxin known. Interestingly it doesn't need oxygen to grow, in fact it is actually an obligate anaerobe - it needs an absence of oxygen. It prefers the absence of other bacteria, it doesn't produce gas as it grows (so cans don't swell indicating that something is wrong) and the spores often germinate after a significant heat treatment. It's also the most heat resistant pathogen, which is why it is the target organism of the canning process.", "The can is sealed by a hermetic seam, and must pass several quality assurance checks before it leaves the factory. The food is put in the can, and then sealed before being sterilised to kill all of the bacteria that are present. If there is any kind of leak on the seam, the bacteria are free to enter and the can, can (in extreme cases) explode under the pressure of the increase in volume due to the bacteria. Here's a picture of the double hermetic seam used to seal cans: URL_0 : TLDR: there is nowhere for bacteria to enter the can, and therefore it cannot perish. Source: specialist canning engineer", "Pretty much just seal the food in an air tight container, like a metal can, then boil the can in water to kill off all the germs inside of it with the extreme heat. Afterwards more germs can't get in the sealed container. Works pretty darn well.", "Food ruining baddies are killed after the can is closed. No more can get in afterwards to ruin your food", "Food doesn't just go bad on its own. It has to have bacteria or germs to make it go bad. When you can or jar food, it removes these factors. Without them, it can stay good for an extremely long time.", "After boiling and killing them what happens to the germs inside the can? they stay inside? evaporate?", "To ride on OP's question, assuming the container is in perfect condition, will the food ever go bad?", "ELI5: How does the heating process not end up cooking the food?", "Food doesn't just go bad on it's own, it's germs that make it go bad. Canning kills all the germs in the food, and stops new germs from getting to the food.", "This question would be better in reverse, given that conservation of food kill all bacteria and seal it. What makes it eventually go bad? Usually it is that the package itself doesn't hold up. So storing the can in a friendly environment helps it last longer. If the date on the package says 5 year from production, the product can be safe to eat 20 years later. Do not buy damaged cans for long term storage. Avoid humidity or even wet places to avoid rust. Avoid temperature swings so the expansion contraction of the content stress the can and its seals."], "text_urls": [[], [], ["https://www.google.co.uk/search?q=hermetic+seam&amp;rlz=1CDGOYI_enGB604GB604&amp;hl=en-GB&amp;prmd=isvn&amp;source=lnms&amp;tbm=isch&amp;sa=X&amp;ved=0ahUKEwiDnJTr9aXSAhVsCcAKHRhpDGIQ_AUIBygB&amp;biw=375&amp;bih=591#hl=en-GB&amp;tbm=isch&amp;q=hermetic+double+seam&amp;imgrc=sxRD4EKv6VNaCM"], [], [], [], [], [], [], [], []], "score": [1473, 101, 87, 62, 25, 18, 8, 6, 3, 3, 3]}}, {"q_id": "5vp30n", "category": "Repost", "title": "Why does all planets have semi-spherical geometry?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["de3q38c"], "text": ["Lets say a large object is in space, large enough to have its own gravity. Gravity pulls from every side pointing towards the middle of the object. Other smaller objects come along and gets pulled along with the large object. Its very similar to how rolling a snowball into a snowman works."], "text_urls": [[]], "score": [5]}}, {"q_id": "5vqdi7", "category": "Repost", "title": "Why do people think they can tell when someone is looking at them?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["de40970", "de451de"], "text": ["As humans, we're often lousy at trusting our intuition when it comes to validating a belief. We tend to ignore evidence that conflicts with an assumption, and overvalue evidence that agrees with it. So if we get a prickly feeling, and we look around, and make eye contact with someone, we think 'oh the prickly feeling was from someone looking at me.' We may get 100 other prickly feelings, look around, and see nothing, and go back to what we're doing, and never think of it again. Then we get a prickly feeling, and make more eye contact, and we think \"See?! I can TELL!\" even though statistics are not on our side. We remember our 2 successes, 3 successes, and so on, and forget about 100 failures, 200 failures, etc. Add to that other factors that can help further the belief: we're predisposed towards eye contact and our brain seeks out faces in our visual field with alacrity, other people are apt to look up when they see us moving around, and they will look towards our face, and we may notice people with other senses than vision without realizing it, prompting us to look around, and you wind up with an easy recipe for thinking we've got an extra sense.", "You know how when you wash your car, it always rains? Of course it really doesn't, but you are more likely to remember the time when this happen, leaving the impression is occurs more often than it really does. This is known as confirmation bias, and all humans experience it. Similarly, when you look up just when someone is looking at you, it makes in an impression you remember. But you don't remember all the times you looked up and someone wasn't watching you."], "text_urls": [[], []], "score": [8, 3]}}, {"q_id": "5vt1ss", "category": "Repost", "title": "Pyramid Schemes, what are they and how do they work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["de4mv8u"], "text": ["Let's say you tell two people that something good will happen if they give you a dollar, and they can also have something good happen to people who give them a dollar, so long as they give you half of what they earn. In turn, they both tell two people they talk to the exact same thing, so you have four people who give the first two people a dollar for a total of $4. In turn, those people give you half of those dollars, so you get $2 and they're left with $1 each. Those four people do this again, so you have 8 people at the bottom layer. Money changes hands: $8 - $4 - $2. Then again: $16 - $8 - $4 - $2. The people at the bottom are funding the people at the top. That's the basic structure of a pyramid scheme. Of course, IRL, it's not that simple. Usually, people become sellers of a brand's product with the option of franchising, but the money is really in the franchising and not the sales. It's just made to seem like a legitimate sales business so they can sucker new people into joining the bottom layer of the scheme. If new members aren't being added, money isn't being paid out and the business collapses. Pyramid schemes exist worldwide, and almost every country has laws against them."], "text_urls": [[]], "score": [3]}}, {"q_id": "5vu2i5", "category": "Repost", "title": "Why size of same ios apps are more then that of android apps?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["de4yp4d"], "text": ["Could be explained by many things: 1. iOS apps might be using a more verbose language. They're developed in Swift or Objective-C. Android apps are typically developed in Java. Java has a reputation for verbosity, but Objective-C might actually be worse. Doing something in Java might just require less lines of code than to do that same thing in Obj-C or Swift. So potentially the application code is just longer in the iOS apps. I don't think this is the case. 2. The amount of code you need to write for an application depends a lot on the external libraries you can include. A \"library\" in programming is just some code that someone else wrote, that you can include in your app. These will cut down on the code you need to write, but may increase the total lines of code in the app (because the library is included). Often, using an external library will be more total lines of codes than doing something yourself, as that library is likely to include edge cases and logic that you don't end up using. So it could be that iOS has more (or larger) third-party libraries, making the total lines-of-code higher in iOS apps than Android apps. This might be a partial cause (you could check by looking at open-source applications and seeing the size of their codebases). 3. Besides third-party libraries, you need to include all the code necessary for your application to work on a mobile device. iOS and Android provide SDK's, so that you can build apps that work on those platforms. So in addition to the user code and the user's libraries, there's also all the platform code necessary. For example, Apple doesn't make it's developers re-create a \"Button\" object - they want to make common stuff easy to use, and they implement that for you. iOS could provide more lines of code out of the box. 4. Before building applications, the code is often run through compilation steps, to turn it into something that the mobile device can actually run. Additionally, some apps may include steps of minification or obfuscation (shrinking or obfuscating the code, for example by replacing a variable name like \"facebookUsername\" with \"a\" - harder to read, but shorter and just as easy for the computer to execute). So compilation steps will be a large factor - it might be the case that Android apps are smaller because Java compilers do better than Objective-C or Swift compilers. 5. Besides code, applications include assets (images, files, videos). To cover different screen sizes and devices, often duplicated assets need to be provided (like one for small displays, one for large). iOS might require more here than Android does - I don't think so though, since they have fewer screen sizes they need to support. Hope this makes sense. The difference is due to either the code and assets in the project, or the compilation steps that turn that code into something that runs (a built, executable program). There could be more causes, but I'm guessing causes 3 and 4 are mostly responsible for file size differences."], "text_urls": [[]], "score": [3]}}, {"q_id": "5vwd9w", "category": "Repost", "title": "What is autism? And what is the difference between mild autism and high-functioning autism?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["de5ic2l", "de5rjc0", "de5lrbz"], "text": ["Autism is a pervasive developmental disorder, giving rise to a range of symptoms concerning perception, behaviour and intellectual capacity. People with autism range from severely handicapped to almost normally functioning. The severity of autism is a continuum, referred to as the autism spectrum. In the most recent diagnostic manuals, the several subtypes of autism have been removed, and the diagnose is now Autism Spectrum Disorder, which includes such diverse previous diagnoses as Asperger syndrome (normal to high intelligence) to seriously disabled patients in need of constant care. In reference to another answer here which defines \"high functioning\" autists as \"being able to function, on some level, without constant supervision\", I find this to be seriously under-representing the capacity of these people, as many high-functioning autists are able to live perfectly normal and independent lives. Source: Am parent of \"high-functioning\" autist (Asperger).", "Aspie here. I don't mean to toot my own horn here but aspies are generally smart but lack the natural development of social skills. Think of it as a permanent item in an RPG that grants +15 intelligence but -15 charisma.", "What is autism? The important thing to recognize is that \"autism\", as such, does not appear to be a single, discrete disease. Not like, say, Down Syndrome is, anyway. Down Syndrome is the result of a *very* particular genetic defect--having an extra copy of chromosome 21--and it produces a very well-recognized set of symptoms, through a series of very well-understood mechanisms. Precisely what symptoms any particular individual winds up with seems largely random, but we have a pretty good working knowledge of what's going on. This is *not* true of what is now known as \"autism spectrum disorder.\" The term is basically a catch-all for a variety of brain disorders that, for whatever reason, produce a related set of *symptoms*, rather than a term that refers to a specific, identified *disease mechanism*. These disorders have to do with both the internal structures of the brain and the connections between various brain structures, but they're not all the same. If there's any single, unifying cause for the conditions we describe with the term \"autism,\" nobody has identified it yet. It's not even clear whether it's a collection of related disorders with similar mechanisms, or a wildly diverse set of disorders that only produce the symptoms we recognize as \"autism\" by chance. In short: we don't really have any idea what \"autism,\" as such actually is. It's just a diagnosis we apply to anyone that suffers from a particular spectrum of symptoms. With respect to Asperger's Syndrome, the reason people say it's \"outdated\" is that it's no longer officially recognized as a distinct diagnosis. Psychiatric/psychological disorders are officially categorized in the Diagnostic and Statistical Manual (usually referred to by the acronym \"DSM\"). In the previous version of the DSM, the DSM-IV, Asperger's was a formally recognized diagnosis largely independent of other conditions. But the DSM-V has recategorized it as a sub-species of what is now known as \"autism spectrum disorder.\" Again, autism isn't necessarily a single *disease* as much as a related set of *symptoms*. The re-categorization of Asperger's is consistent with that perspective."], "text_urls": [[], [], []], "score": [24, 5, 4]}}, {"q_id": "5vwu1t", "category": "Repost", "title": "Why is the USA more conservative on attitudes about sex compared to other developed nations?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["de5iuc4", "de5jpsd", "de5oikr"], "text": ["I think it's because the country was founded by Puritans who fled the United Kingdom because they were on the other side of religious persecution, being a minority religion in a majority Protestant country. In the New World, they were free to do the oppressing and forbid any fun activities. They kicked Roger Williams out of Massachusetts Bay for \"spreading new and dangerous ideas\" like religious tolerance and separation of church and state. They also kicked out the Quakers and executed four by hanging when they stayed behind and kept practicing. Nice guys, these Puritans, don't you think? The enforcers of religious dogma seem to be obsessed with people's sexuality. Controlling when and how you procreate and what you're allowed to teach your offspring creates a ready-made army of God. There's no higher purpose than that, really.", "Americans have this thing called Bible Belt. America only tolerates religious fundamentalism and extremism of the Jesus variant.", "It's because of the way the USA distributes power unevenly to the rural areas of the country. There are many areas of the country with relaxed attitudes about sex on par with Europe (Las Vegas, New Orleans, New York, San Francisco, etc). However, rural areas have a disproportionate voice in the Senate and Presidential elections so they still get to make the rules."], "text_urls": [[], [], []], "score": [19, 9, 5]}}, {"q_id": "5vy6f7", "category": "Repost", "title": "If there's no air in space, that mean there should be little to no friction. Why can't we just reach the speed of light by burning fuel in a particular direction for A while?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["de5se0m"], "text": ["This works for a while, but once you actually start to get close to light speed the usual f=ma physics stop working so cleanly. At speeds that are an appreciable fraction of light speed (c) the energy required to continue accelerating begins to increase exponentially. Going from .8c to .9c takes far more energy than 0 to .1c, and the energy cost quickly becomes prohibitive. No amount of energy in the universe can propel an object with mass to 1c, the equation approaches infinity. There are also more practical problems like fuel load, acceleration time, stopping, ship controls, and impacting stray dust particles at relativistic speed."], "text_urls": [[]], "score": [3]}}, {"q_id": "5vz0en", "category": "Repost", "title": "How do some justify that the holocaust was fake?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["de5zg76", "de5zjg4", "de63rpg"], "text": ["They deny that the sources attesting to it are accurate. Since we are now reaching a point in history where many of the first hand witnesses are dying, it is in the process of passing out of living memory. This is usually ideologically motivated, because the people proposing it either want to reduce sympathy for Jewish people, or because they want to promote a set of policies widely associated with Nazis. There is usually an element of conspiratorial thinking involved in promoting this viewpoint--that somehow a conspiracy of individuals has lied to the world to create the impression that the holocaust happened. This is also used by some groups as a way to fish for individuals who might be vulnerable to this sort of thinking in general. Many groups will pay special attention to recruiting individuals who accept holocaust denial, because that indicates that they are--at the very least--not strong critical thinkers, and not sympathetic towards Jewish people. This makes them ideal recruitment candidates for ideologically extreme political and religious groups who are historically anti-semitic.", "When your goal is to prove a point regardless of the facts, you selectively read and pick evidence that supports your position and reject all contrary evidence for whatever reason you can come up with. Holocaust deniers dismiss the testimony of thousands of survivors, archaeological artifacts, and contemporary second-hand accounts made during or shortly after the war. They also make make strawman arguments like \"The gas chambers couldn't have killed 6 million people!\" (that's true, but 6 million people is the total number that died, not the number killed in gas chambers). These threads from /r/askhistorians address this topic more in-depth: URL_0 URL_2 URL_1", "In some countries, Not the USA, not western Europe, history is taught poorly and press is not free. So you can say to your people who cannot read another language than their own, everything. In my country, many children of North African ancestry did not believe that the killing of 6,000,000 Jews had happened. In 1945 the people of Germany and the rest of Western Europe could hardly believe that that had happened. The children were taken to a trip to Auschwitz to see the Vernichtungslager, to see the human hair that was cut of the death bodies before they were cremated, the spectacles. Then they could also believe the stories about soap made out of human fat, the lampshades made of human skin. The terrible experiments performed by Doctor Mengele. Free press, no censorship is very important. People in the USA or Western Europe who have access to all sources should not deny this genocide. If they do it is blatant lying."], "text_urls": [[], ["https://www.reddit.com/r/AskHistorians/comments/57w1hh/monday_methods_holocaust_denial_and_how_to_combat/", "https://www.reddit.com/r/AskHistorians/comments/z9ywa/how_to_deal_with_holocaust_denial/", "https://www.reddit.com/r/AskHistorians/comments/1n3vwo/do_holocaust_deniers_have_any_valid_points/"], []], "score": [13, 5, 3]}}, {"q_id": "5vz5bw", "category": "Repost", "title": "How does VX (the nerve agent that killed Kim Jong-nam) kill you even with a tiny amount applied to the skin?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["de60ixe"], "text": ["From Wikipedia: *\"VX blocks the action of acetylcholinesterase, resulting in an accumulation of acetylcholine in the space between the neuron and muscle cell, leading to uncontrolled muscle contraction. This results in initial violent contractions, followed by sustained supercontraction restricted to the subjunctional endplate sarcoplasm and prolonged depolarizing neuromuscular blockade, the latter resulting in flaccid paralysis of all the muscles in the body. Sustained paralysis of the diaphragm muscle causes death by asphyxiation.*\" TLDR? VX stops communication between your nerves and muscles, causing your diapraghm to stop working, which makes you suffocate."], "text_urls": [[]], "score": [17]}}, {"q_id": "5w0rwt", "category": "Repost", "title": "Why does eating spicy food make my nose run?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["de6et0f"], "text": ["It's an inflammation response. Many spicy foods, especially those made with chili peppers, contain an oil called *capsaicin* which is a very powerful irritant to mucous membranes in mammals, such as the eyes, nose, and throat. This is a defense mechanism from the chili pepper plant's perspective, since the GI tract of a mammal would wreck the seeds as they passed through and out. Birds can't taste capsaicin, and along with their relatively gentler digestive system and their ability to fly, the seeds from a chili pepper are much more likely to survive and be spread much farther away. Other spicy foods like horseradish use a different mechanism to produce their spicy taste, but that's a different story."], "text_urls": [[]], "score": [21]}}, {"q_id": "5w0uro", "category": "Repost", "title": "Why are human babies born so incapable of survival compared to other animal babies?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["de6f8l6"], "text": ["We have big brains, which means we need bigass heads. Big heads do not fit through a primate pelvis particularly well. So the compromise is to have babies early, before their brains are fully developed. Because we are a smart and social species the group can protect the helpless young, so it isn't a huge evolutionary disadvantage."], "text_urls": [[]], "score": [4]}}, {"q_id": "5w13qe", "category": "Repost", "title": "What is an SHA-1 and an SHA-1 collision?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["de6iplw", "de6l0gx", "de6i5r7"], "text": ["A hash is a one way math function that can't be reversed. It's most common use it to store passwords. So say you have a number 2345 and you have a hash algorithm that adds the numbers together. The total is 15. From 15, you can't get the original number, but you can figure out IFA number you receive matches 15. So you store 15. Now someone says my password is \"3456\" , you add it all up and get 18. 18 doesn't match 15 and you know that it's not the right password even though you dont have the original password. Now someone finds out you have stored 15 and that you add the digits together to get the password and send you 5550. Using your algorithm, you add the digits and get 15. So you know it's the right password. Crap! Now, you have two different numbers but with the same password. SHA1 is like your algorithm but much more complicated. The two passwords are a \"collision\" because they have the same result from your algorithm. Now let's pretend that you use your algorithm to sign something. \" The file I sent you, when run through my algorithm gives a result X.\". A hacker could generate a different file and craft it so it has the same result and you would think it's the original because it has the same result from your algorithm. In the real world, SHA1 is no longer used for security stuff because it was declared unsafe 1-2 years ago. Please excuse any mistakes in my message, I am kinda drunk.", "SHA-1 is known as a hashing algorithm. Note that I will be talking about hashing algorithms in general here, since the only thing different between them and SHA-1 is that the math behind them is different. This is something which you can use for several different purposes, but generally used to make sure that two different sets of data are identical. You take a set of data, be it a file or a phrase, run it through a program that applies the SHA-1 algorithm to it, and out you get a 40 character hexadecimal, or 20 byte long phrase known as a \"hash.\" For example, I ran the hashing algorithm through a random file I have, here is its hash. SHA1: 0DA324A381B410ACBAF6857BF577C0998FF53842 Now, there are several important things about hashing algorithms in general. Firstly, they always produce the same hash when the same file is run through it. Second, it is destructive, meaning that the hash cannot be turned back into the original file. For example, a simple hash for a bunch of numbers would be just to sum the digits, you take the number 456, sum the digits, you get a hash of 15. Any time you sum the digits, it will always be 456, but you can't get 456 out of 15 necessarily. Point is, it is not reversible. So, what is it used for? A variety of things, but generally to make sure that two copies of data are the same. For example, some smaller software devs, especially open source ones, will list the SHA-1 hashes of their files when downloading them to verify that the download is correct. Another good example is that of WikiLeaks, they have their data mirrored by many people so that in case the main site goes down, people can still access it. But how do we verify the data is legit. Through this algorithm, these hashes are small enough to say tweet or do something similar, so this way, people can verify that their downloaded files are legit. Another use of this is for password storage. Websites (at least the good ones) like Reddit NEVER store your password in a normal text file, or store it at all. Instead, their database will contain the hashes for all the passwords. When you login, you send your password over through an encrypted connection, the server will take your password, run it through the hashing algorithm, and check that the hash matches that for your user in the database. Why is this important? So that in case the database is leaked, your password is not. Beside this, it has significantly more uses with things like SSL certificates and complicated stuff I don't want to get in. Point is, it deals with a lot of security stuff. You might have noticed above for our simple hashing function of summing the digits, there can be multiple phrases that fit that hash. Like 285, or 852, or 366. This is true of all hashing algorithms, it is a basic fact of math that to verify that two sets of data are the same, the only way to do so with 100% accuracy is to check each point of data in each set of data and see if they match. A hashing algorithm works 99% of the time. That brings us into the next question. What is a hashing collision? It is when two files or pieces of data have the same hash. Now, this is not good. Hashing algorithms are important since they verify the identity of a piece of data, and if a piece of data can pretend to be another piece of data... well, this is no bueno. The fact is that hashes are small enough to be feasible to say copy paste or write down, but large enough so that they are complex enough to avoid collisions like this happening just by pure luck (more letters and numbers in the hash, more things it can be). The main thing is that you can manufacture data that has the same hash as another piece of data. For example, if someone finds a phase of numbers and letters that has the same hash as your reddit password, they can login with that into reddit, even though that is not the password you set. So, what happened today. Google released 2 pdf's today. URL_1 URL_0 These are different PDFs. But they have the same SHA-1 hash. They claim to have figured out a simpler way to find a hash collision for SHA-1 and will publish the method for how to do so in 3 months (waiting 3 months so that anything that uses SHA-1 has time to switch to a more complex algorithm like SHA-256 or SHA-3). By simpler, I mean one that still requires $100,000 worth of computing power, but point is, they found a way that isn't unfeasible. Any security relying on SHA-1 has to switch now basically.", "Sha-1 is a so called hashing algorithm. Basically its an assembly line for your password, where the end product is scrambled, skewed, reversed etc in a way that is consistent but makes it impossible* to go the other way up the assembly line and figure out what the starting product was from an endproduct. Imagine that you create an account on a website and you put in your username and password you want. The password then passed through the SHA-1 chain which outputs a scrambled piece of data. This way, if someone ever gets hold of that scrambled data, he/she could never find out what your original password is. When logging in, the password you put it goes through the SHA-1 chain and then compared to the saved SHA-1 string. * This has now been broken, which ties into the SHA-1 collision where two strings of text could end up being the same result."], "text_urls": [[], ["http://shattered.io/static/shattered-2.pdf", "http://shattered.io/static/shattered-1.pdf"], []], "score": [17, 11, 3]}}, {"q_id": "5w1zxx", "category": "Repost", "title": "why do women's periods sync up when they spend a lot of time together?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["de6ozlg", "de6p0t9"], "text": ["They don't. It's a common myth. What happens is that most women's periods have *roughly* the same length. This means that they will drift in and out of sync as time passes. It's only really noticeable when they're in sync. In a more easily observed example, notice how the turn signals of cars seem to be in sync for a bit then drift off after a while. If you want a visual demonstration [watch all of these pendulums making patterns & chaos]( URL_0 ).", "They don't. Statistically, any set of sequential events that each occur at a roughly persistent interval are bound to line up eventually. Think of it like a line of cars in the turn lane at a red light. All of those turn indicators blink at their own persistent interval, and each of those intervals is *slightly* different from the one behind it; but if you watch long enough, there will be a few times where a few of them seem to blink in unison a few times before falling out of sync again. And if you watch even longer, eventually **all** of them might appear to blink at the same time. But they eventually fall out of sync again as well, because they each blink at their own specific frequency completely independent of each other. Then there's always the healthy dose of confirmation bias that we're so prone to. You remember all the times you and your lady friends' cycles matched up because that shared event is remarkable. But you disregard the dozens of times they *didn't* line up."], "text_urls": [["https://www.youtube.com/watch?v=yVkdfJ9PkRQ"], []], "score": [13, 3]}}, {"q_id": "5w2din", "category": "Repost", "title": "What are Ponzi schemes and why do so many people fall for it even after being in the news so much?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["de6s8rl"], "text": ["A ponzi scheme is a kind of fraud where the scammer uses money they get from \"new\" clients to pay \"dividends\" to older clients. It's a *little* like a pyramid scheme. The idea is to get enough people buzzing about getting good dividends to capture a lot of people. The scammer then just takes the bulk of the money, distributes \"dividends\" as long as they are able to increase their scam base, and eventually just disappears with all their cash. People fall for them because it isn't always abundantly clear that one is going on. Did you just find a really good investment, or is it a scheme? Unless you know how to do your research, you probably aren't equipped to *truly* tell the difference until its too late. The way to avoid them is to: 1) Consider investing in mutual funds and investment houses. Something like Oakmark can yield decent returns. 2) Understand that the saying \"It's too good to be true.\" Amazing profits? It's almost certainly a scam. 3) Avoid 'buying' a way to wealth. If someone is selling you a method to get wealthy, then why aren't they just using it themselves to get crazy wealthy? 4) DO. YOUR. HOMEWORK. Google shit. Find news stories on major financial sites. Go dig around places like reddit. Finance and investment dorks LOVE talking about these things. Find a group and pitch an idea and just like any other topic you'll find loads of peopel ready to say \"yeah that's awesome\" or \"no that's a scam\""], "text_urls": [[]], "score": [5]}}, {"q_id": "5w2ji7", "category": "Repost", "title": "If the stars and planets are light-years away, are we seeing the planets that many years back?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["de6tdbp"], "text": ["Yes. Everything we see in the sky is from the light it generated/reflected in the past. Even the sun is several light minutes away, so we are always seeing it as it was a few minutes ago. A star 10 light years away, we will see the light that is now 10 years old. The further an object is away, the further in the past our perception of it is."], "text_urls": [[]], "score": [3]}}, {"q_id": "5w6voe", "category": "Repost", "title": "Theory of relativity", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["de7qu7i"], "text": ["Einstein made two postulates: * All observers in frames of reference with constant motion (i.e. no acceleration) will always observe light to be travelling at the same speed, approximately *c* = 300,000,000 m/s. * There is no privileged reference frame with which all things move with respect to, or in which observations are inherently correct - all observers move relative to each other. From these two postulates and some basic maths, Einstein draws some remarkable conclusions: * Observers will see the clocks of others who are moving with respect to them tick slower - this is called time dilation. The closer they travel to the speed of light, the greater the dilation. * Observers will see the path they travel shorten parallel to their direction of motion - this is called length contraction. The closer they travel to the speed of light, the greater the contraction. * Observers will not necessarily agree on whether two events were simultaneous or not, depending on their state of motion. * No object with mass can accelerate to the speed of light. Velocity is also no longer linearly additive. * Mass is a form of energy, and an object's energy tends towards infinity as it gets closer to the speed of light. This is the special theory of relativity. If you want to see an intuitive and simple derivation of time dilation, look up the Light Clock example. In the general theory of relativity, which is a lot more complex, Einstein deals with gravity. He tells us that space is curved by the presence of mass (like a bowling ball on a trampoline) and the curvature of the path of objects through space is the force of gravity. I realise I'm essentially listing things about relativity, and that's because the reasoning behind it is deep. If you want to know more about any particular things, or you have some confusion (there are plenty of apparent paradoxes when you start to think about the logic), then I can try to elaborate."], "text_urls": [[]], "score": [4]}}, {"q_id": "5w8jbu", "category": "Repost", "title": "Why are Microsoft computers more prone to viruses compared to Apple computers? Also why does Microsoft have so many more operating system updates compared to Apple?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["de84o2d", "de84ixi", "de855mp"], "text": ["Microsoft is maintaining backwards compatibility with operating systems which presumed that each PC was an island, unconnected to anything else. There were few security checks, because there were few security threats. This approach encouraged lots of hardware and software vendors, making the windows marketplace the largest market (for making money) and the largest target (of evildoers). Apple had a different market strategy, strictly controlling who could make what hardware and software. They did this to control the user experience, but it accidentally turned out to promote security once all personal computers were on the Internet. They did it to promote \"Apple computers just work\" even though that might mean \"they don't work with that non-Apple stuff\". Since Apple doesn't make malware (neither does Microsoft, by the way) this turned out to make malware much harder. Evildoers are not going to work harder to target a smaller part of the marketplace. It's a little like having a security sign in your front yard, the crook just decides to break into the house next door.", "Not enough people use Apple Computers to justify making viruses for them? #ShitPost", "It's the economy of scale, more people use Windows. Therefore there's more incentive to create viruses for it. Also Apple is expensive, and most viruses come from poor Eastern Europe and Russia. Not many hackers can afford one."], "text_urls": [[], [], []], "score": [20, 6, 4]}}, {"q_id": "5w9es3", "category": "Repost", "title": "Why do sounds like fingers scraping on chalkboards get a reaction from our body?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["de8c4co"], "text": ["Overall, research shows that this ear-splitting noise has the same frequency as that of a crying baby and a human scream, indicating that these sounds are tied to survival. For instance, people attuned to these frequencies may rescue a crying infant sooner, improving the baby's longevity."], "text_urls": [[]], "score": [15]}}, {"q_id": "5w9pb5", "category": "Repost", "title": "Why can't relative speed go above the speed of light? (That is two objects moving towards each other, both near the speed of light)", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["de8ef8a"], "text": ["This is the basis for relativity - even relative speeds can't go above the speed of light (I might call it c below to save time) because space and time bend in order to make it work. I'll try give a brief explanation, but it all comes down to reference frames. A reference frame is the \"point of view\" you use when you measure your speed. If you're driving along a road at 20 mph and you pass a pedestrian who is stood still on the sidewalk, then I'm sure you know that your relative speed is 20 mph. From the point of view of the pedestrian, he is perfectly still and your car goes past him at 20 mph. That's his reference frame. From your perspective, it's perfectly valid to say that you and your car are perfectly still, and the pedestrian, and even the rest of the world, are moving past you at 20 mph. That'd be your reference frame. In everyday life you usually don't consider things this way, but from a maths/physics perspective it's completely valid to define your point of view like that. In case that's difficult to get your head around, I'll give another example. If you're with me so far, you're welcome to skip this paragraph. But consider you're in a spaceship, flying away from teh earth at a relative speed of 1000 mph. From the perspective of (or in the reference frame of) people on earth, they are stationary and you are moving away from them at 1000 mph. But from your perspective, it's equally valid to claim that you are sitting still and the earth is moving away from you at 1000 mph. This is because there's nothing which is \"absolutely still\" so all speed has to be defined as relative to something else. Now this is all fine, but when we start approaching the speed of light, funny things happen. We observed through a range of experiments that it doesn't matter if you're moving relative to the direction of the light, no matter how you measure it, the speed of light will always come out as the same number. Before we go further it's worth noting that this isn't accounting for optical phenomena like refraction - things like the speed of light moving at smaller proportions its speed in a vacuum in certain substances. When I say the speed of light in this explanation, we ignore all the stuff like that because it's irrelevant and would only make things more complicated. But it turns out, from various measurements that **the speed of light is constant in all reference frames**. That's in bold because that's the \"postulate of invariance\" of special relativity, which is one of the basic laws of the theory we derive everything else from. To give an example of this - consider you're in your car (which has had a bit of an upgrade to allow it to travel at very, very high speeds) and you're travelling alongside a light beam. If you measure how fast the light beam is relative to you when you're not moving, you get the ordinary speed of light, as you might expect. But if you start driving alongside it, it doesn't matter how fast you go - even if you go at 0.99c (that's 0.99 * the speed of light - in reality it's a very messy and long number so proportional terms are easier to think about) then you will still always measure that light beam as going at the same speed relative to you. That may not make sense at first, and you may expect that when you're travelling close to the speed of light that then the beam would appear to \"slow down\" relative to you, but it's simply not the case and has been shown through various experiments. It also follows that you can't ever reach the speed of light - the amount of energy needed to accelerate you tends to infinity as you approach c, and we know that there isn't infinite energy in the universe, so that simply means that we can't ever reach the speed of light. Now consider your example of two objects moving towards each other at approximately the speed of light - how about we assume that they are both travelling at 0.8c in a \"stationary\" reference frame to make the maths easier. Non-relativistic mechanics would suggest that their relative speed is 1.6c. Now we know from above that it's perfectly valid to consider the reference frame, or point of view of one of these objects - and in that reference frame, if not for relativity then it would be stationary and another object would be heading towards it faster than the speed of light. As we've seen above this would lead to serious inconsistencies - in the reference frame of the object, this would mean that the object hurtling towards it must have infinite energy, whereas in the \"stationary\" reference frame both objects have finite energy. We know that both reference frames must be equally valid, but that inconsistency would mean that they can't be - the solution, then, is that even relative speeds can't be above the speed of light. Now it's tricky to explain what actually goes on, but ultimately space and time start to distort when objects start approaching the speed of light. Length contracts and time dilates to such a degree that no matter your reference frame, no object can travel faster than the speed of light, and we can express and measure this mathematically with a [Lorentz factor]( URL_0 ) where v is the velocity of the object and c is the speed of light. This may sound crazy or made-up but it has been measured experimentally. The [Hafele and Keating Experiment]( URL_1 ) in 1972 put two perfectly synced caesium atomic clocks on planes going around the world, one in one direction and the other in the opposite direction. This meant that they had a relative speed which while a long, long way below c was enough for relativistic effects to kick in. After a few trips, the clocks were no longer in sync - one had gained a few nanoseconds and one had lost a few nanoseconds - and the amount of time they had gained or lost was almost exactly the amount predicted by relativity. Ok, I've written a lot there. I hope I'd helped to answer your question, but if not then feel free to ask me anything you need in terms of clarification."], "text_urls": [["http://file.scirp.org/Html/5-7500526/4d116bf4-c0f6-4707-8e79-4e434eaa81e7.jpg", "http://hyperphysics.phy-astr.gsu.edu/hbase/Relativ/airtim.html"]], "score": [11]}}, {"q_id": "5waan3", "category": "Repost", "title": "What is Red Pill and what does it have to do with sexism on Reddit?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["de8hyix"], "text": ["Red Pill refers to the film the Matrix, where taking the red pill allows someone to free their mind from the Matrix, a giant computer which all humanity is hooked up to creating the illusion of a free world when they are in fact enslaved by ~~aliens~~ robots far in the future. Taking the red pill lets freedom fighters bring people out to the real world to help free humanity overall. In today's parlance, it refers to the idea that society has brainwashed people into some kind of PC liberal ideology where women are getting a free ride at the expense of the rights of men. This often also applies to minority ethnic groups and white people. Those who have taken this so-called Red Pill have seen the world for what it truly is, recognise that sexism is made up, the Patriarchy doesn't exist, women have it easier and feminism is slavery, and they are trying to free all the rest of us. It is used to justify the attitude these people have towards women and minorities and it commonly goes along with far right political leanings akin to fascism. Please note that I do not agree with this point of view."], "text_urls": [[]], "score": [6]}}, {"q_id": "5wdng4", "category": "Repost", "title": "How do woman's periods sync up?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["de99ahw", "de998f5", "de9a353", "de99z9u", "de9bj8g"], "text": ["They don't. If you have a number of women living together for a long time, it's likely that at some point at least two of them will have a period at the same time. People present this as evidence for the claim, when it's really just chance. The end of this article has an interesting visualisation of this: URL_0", "They don't. It's a pretty common myth, and a lot of people still believe it, but it isn't true. It's just a coincidence that people tend to notice, especially since periods can last up to 7 days. Two women with 1 overlapping day cover nearly half the month, so add 1-2 more women in to the equation and it's nearly certain that there will be some overlap.", "They don't. The original study was published in 1971 and subsequent attempts to replicate the study failed. Also, there were problems with the original study as well. [Wiki link]( URL_0 )", "Most women's cycles aren't truly 28 days, they vary and can change month to month, that's just the average. And some women vary wildly in the length of their period (before the pill my periods would last anywhere from 2 days to 8, but usually 4-5). Ultimately, its a stupid myth. Anytime you get a bunch of women (who aren't on then pill) together, someone will 'sync' eventually. For a week.", "Have you ever been on a turning lane at a stop light with other cars in the lane and everyone has their blinkers on? And every once in a while a few of the cars blinkers seem to \"sync up\"? But after a while they get out of sync again? Similar principle. If you have many women together for long enough, it will appear that their cycles will sync together, but as others have stated, it is a myth."], "text_urls": [["http://www.bbc.co.uk/news/magazine-37256161"], [], ["https://en.wikipedia.org/wiki/Menstrual_synchrony"], [], []], "score": [20, 17, 6, 5, 5]}}, {"q_id": "5we9bb", "category": "Repost", "title": "How are different domains(.com, .net, etc.) created and how do we connect to them?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["de9h0pr"], "text": ["There's a set of servers called \"root name servers\". These servers are managed by ICANN (Internet Corporation for Assigned Names and Numbers) and form the basis of the domain name system. Only top level domains (.space, .io, .tv, .com, .net) that are recognized by ICANN and placed in these root servers are visible on the internet. You can't just arbitrarily pick a TLD like .zoiggy and start using it because it is not registered in the root servers. Now, if you want to get your own TLD, all it takes is a $250K check to ICANN and some legal paperwork."], "text_urls": [[]], "score": [5]}}, {"q_id": "5wenpn", "category": "Repost", "title": "why did the natives (north and South America) die to diseases from Europe but Europeans didn't die from native diseases?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["de9i88l"], "text": ["Europeans had been living in denser populated cities for a lot longer, and they had wider trade routes across more of the world for a lot longer, exposing them to more diseases over longer periods, helping them build immunities (or at least weeding out people with the least resistance) to a wider range of pathogens. Thus the Europeans were far more likely to be resistant to whatever the new world people had than the other way round"], "text_urls": [[]], "score": [4]}}, {"q_id": "5wh2vn", "category": "Repost", "title": "Why do we get sick of eating the same food?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["de9z3n2", "dea104s"], "text": ["I know people who don't and it's weird. My ex husband would eat stuffing and hard boiled eggs everyday for months and months", "A balanced diet is important to make sure you ingest al the necessary vitamins, proteins... and such that your body needs to make it work. As an example: your body needs a certain component of proteins it makes, an amino acid called lysine we cannot make in our own body (that's why it's called an essential amino acid). A person eating lots of cereals and nothing else (which was / is the case in some poor countries), won't get enough lysine, as it is (almost) not present in those foods. Their bodies won't be able to make some proteins necessary to get their bodies to work properly, and they'll get sick."], "text_urls": [[], []], "score": [3, 3]}}, {"q_id": "5whzc4", "category": "Repost", "title": "Since we use programs to write new programs, how were the first computers programmed ?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dea6db5"], "text": ["There's something even earlier than punch cards, though the other guy's example is good. URL_0 Sit through this quest of tedium, if you dare. Early computers were programmed with switches. Up for a 1, down for a 0, press a button to put that data in and move onto the next memory bank, do that dozens or hundreds of times, press \"run\", then watch the red lights on the front for your answer. That's. It. This required understanding binary and figuring out exactly what the code should be with nothing but scratch paper and your brain."], "text_urls": [["https://www.youtube.com/watch?v=Qab-960Dl1E"]], "score": [9]}}, {"q_id": "5wi8gs", "category": "Repost", "title": "How do airlines get away with overbooking flights?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dea8r05", "dea8qey", "dea8jlr"], "text": ["Because there's no law against it. When you buy a ticket they are not guaranteeing you a seat, it's right there in the contract. If you don't like it, use an airline that does not overbook their flights. You should expect to pay a higher price for that airline. You can't have the best of all worlds, part of how airlines get their prices down are by overbooking flights. (the flowing numbers are 100% fictional) They know that on average for every 100 seats sold only 98 will show up at fight time. So on a 300 person flight they'll have 6 empty. While that 98/100 is a simple average, they also know what the standard deviation on that average is. This means that they can make a statement like if we sell 306 tickets for a 300 seat flight, it'll only be a problem 1 out of 100 times. They make a business decision that it's OK to piss off 1 out of every 3000 customers if it means more revenue per flight (and therefore a lower price per seat).", "I've heard that there is a certain percent of no-show among passengers (non-refundable tickets). Knowing that airlines sell more tickets than they have seats. Surprisingly, they prefer the risk of paying a compensation to a person who they didn't have a seat for, meaning that they get more money from 'no-show' people. So, basically, it's a gamble.", "Because on average a certain number of people won't show up, and flying with empty seats is more costly since they use the same fuel either way (more or less) but sold less tickets for the flight with more empty seats. They *could* only sell as many tickets as there were seats, but this would mean the planes would almost always fly with empty seats so the price of the tickets would have to go up to compensate for this loss."], "text_urls": [[], [], []], "score": [5, 3, 3]}}, {"q_id": "5wiytl", "category": "Repost", "title": "What is true socialism, and why do people think it will save America?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["deah6uj", "deafsqq"], "text": ["Literally nobody thinks it will save America. But certain socialist policies have proven highly effective in the past and in other first-world countries. First, socialism is not a form of government in and of itself. Socialism is an economic model in which the government controls industries and exerts significant control over how revenues are shared. Practically no one, save perhaps North Korea, is 100% socialist. Every modern country has a mix of socialist and capitalist policies. Second, it is entirely possible for a country to implement socialism and still fall into ruin through incompetence and mismanagement (see: Venezuela). When people talk about socialism in America, they normally mean socialized medicine and increased welfare (such as a minimum guaranteed income). The goal is to alleviate poverty and prevent wealth from accumulating in the hands of the very few. That ends the unbiased explanation. My *personal assessment* is that the only rational course of action is to implement at least some socialist policies. Ruthless, cut-throat capitalism as the GOP supports it is untenable. It never has worked and it never will. The market will always require government intervention in order to make it function properly and safely. Certain functions, like medical care and education, have completely failed as capitalist institutions and need to be entirely recast as government-controlled operations. Social welfare programs, especially for the sick and the elderly, are vital to alleviating poverty. And as our planet runs out of fossil fuels and suffers the burdens of overpopulation, we will increasingly require rational government control over how resources are allocated. Again, I must insist: Not saying that all capitalism is evil, but certain functions will inevitably require significant government interventions that would qualify as \"socialist.\"", "Socialism is a system of economics, not government. It's seen as preferable to capitalism (though not necessarily superior) because it allows for more even distribution of wealth and resources eg universal healthcare and tuition-free post-secondary education. This must obviously be funded somehow, and the solution most often proposed is a tax increase, generally applying most to the wealthiest members of a given society. The issue is that very few people honestly want to pay higher taxes regardless of the benefits."], "text_urls": [[], []], "score": [13, 4]}}, {"q_id": "5wj1yx", "category": "Repost", "title": "Why does milk spoil when it's left out at room temperature, but safe to drink warm or add to coffee?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["deagbuv", "deafr4k"], "text": ["Milk spoils from bacterial growth not just heat. Bacteria grow better in warm temperatures and much more slowly when kept cold. Brief periods of warmth or heat does not leave enough time for the bacteria to grow.", "Milk doesn't immediately spoil at room temp, its just a temp at which bacteria will grow faster. Milk can still spoil in the fridge, it just takes longer. Am I misunderstanding your question?"], "text_urls": [[], []], "score": [5, 4]}}, {"q_id": "5wjera", "category": "Repost", "title": "how do you determine when to use affect vs effect?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["deaizri"], "text": ["An Effect is a reaction of something. Affect is an action taken (by you or someone or something. A verb). So you can affect something, and cause it to have an effect. That effect it has could in turn affect you in some way."], "text_urls": [[]], "score": [3]}}, {"q_id": "5wk39u", "category": "Repost", "title": "Why does America need a $58bn increase in the military budget if it's already more than the next 8 countries combined?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["deaonxa", "deapc2z", "deaqd6y", "deapxc0", "deaq4e5"], "text": ["It is subjective if the US *needs* such investment. However there is an enormous benefit to being untouchable militarily and you don't do that by being stingy.", "Short answer we don't. There are many reasons why we increase military spending and one is the fear of decrease. The military in the US doesn't run the US but it benefits greatly from our current system. Their biggest fear is a new Jefferson who asks why we need a standing military so big with no real enemies. So if your budget is $700 billion it's easier to take a 25% cut. There is a smaller portion in my opinion where fear drives the military growth. Not an expert just a reader of history", "It doesn't. But the current leader thinks that spending a lot more on the military provides good optics, and that a bigger military is always better. And the other things the money could be spent on (healthcare, the environment, infrastructure) are not as neat (or he is downright hostile to them). So, with the limited resources we have, he wants even more on the military. It's not about needs. It's about wants.", "2 primary reasons. There was a requirement (by the bush administration) to be able to wage two full wars. This means that while they are fighting a war in iraq, that they can still defend other territories as needed. This leads to the other reason: that there exists many contractual agreements with other countries that while they have stations on foreign soil, that they would agree to defend said soil. It takes large sums of money/resources to defend one's country in order to abide by certain un standards, and some countries can get away with this requirement because the american army is their defense. There are other reasons, but the bulk of why the NA budget is so enormous is because of these. The reason places like norway doesn't have a military budget is because the usa does it for them.", "All these people who dont get free access to healthcare have to choose between saving their mom and keeping their house, but good thing America can take out any nation in the world."], "text_urls": [[], [], [], [], []], "score": [27, 14, 6, 6, 5]}}, {"q_id": "5wkurj", "category": "Repost", "title": "How do Captcha's know that I'm not a robot when all I had to do was click on a box?", "title_urls": {"url": []}, "selftext": "So I understand how most captcha's work, but what I'm wondering is how sometimes it doesn't even make me fill the entire captcha out and automatically decides that I'm not a robot. It just seems odd to me that it can do that right after I click one button and how botters/spammers can't abuse this on their bots.", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["deaxir0"], "text": ["The boxes usually capture mouse movement, to see if it's \"natural\" movement, versus just sending the commands directly. It also looks at your public cookies to see if they're consistent with a real internet user, versus a single-purpose bot."], "text_urls": [[]], "score": [10]}}, {"q_id": "5wl1dq", "category": "Repost", "title": "How do professional mathematicians make a living? Excluding teaching, what other careers exist for pure mathematics?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["deaxweg"], "text": ["Lots of things involve math, and many pure math PhDs do not work in academia, mainly because the wages are far lower than in other fields, like finance, technology, and security work. I know quite a few mathematicians due to my line of work. A few have worked in the academy, but as much as being a professor looks like a great job, there are many drawbacks as well. Many find teaching tedious, the academic world boring, or pure research a chore. Academics have to publish all the time, and many find that merely \"busy work.\" So many mathematicians work in other places, particularly in banking and finance. In the old days, people would research different stocks, bonds, and financial instruments and try and pick ones that they thought would grow or pay dividends. With the rise of financialization in the 1980s, and the rise of computational power in the 1990s and early 2000s, lots of trading and investing is increasingly done by algorithm, that is by computer programs. But these computer programs are very difficult to write, so they need people with strong mathematics backgrounds to write them. They need people who can figure out complex patterns in the markets and the ways to make money off of what is basically a very large real-world math problem. People in this field make a lot more money than professors, and many find the work challenging and fun, because they can put their problem solving skills to the test and have them compete in real markets with real money. Another place mathematicians are working is in robotics and automation, and what could be considered pre-artificial intelligence, or machine learning. These problems all require high levels of mathematical ability, and they pay a lot more than academia as well. I have a friend who works for the government working on cryptology and spying, cryptology is the process by which one takes intelligible things and makes them unintelligible without a special key, sort of like a lock. They are a mathematician, and they break codes for the government. They cannot talk about their work much, but the government needs people who are good at math who can work at really complex problems like trying to figure out what people are hiding from the government, like picking a lock except with computers. There are many other jobs for mathematicians. I know one who was an air traffic controller, which is a very stressful job that requires a strong knowledge of math and excellent quick problem solving skills. Pure math is a very good field, but it is also very difficult at an academic level. There is very little writing, but a great deal of work. Many people who start PhDs in maths do not finish their degrees, as they are offered jobs that pay much better than professors before they graduate, so there are also not that many maths PhDs to actually teach. It is one of the few positions within the university that is difficult to find workers for. Hope this helps!"], "text_urls": [[]], "score": [10]}}, {"q_id": "5woc2x", "category": "Repost", "title": "Why does a photo of a monitor taken from a phone switch form and color as soon as I zoom in or out?", "title_urls": {"url": []}, "selftext": "I don't know if it's a common phenomenon, but when I take a picture of my desktop monitor, the pixels look really weird, it swirls around in every direction and it's all full of little squares. But as soon as I zoom in a bit, everything starts to clear up and none of the structure of those swirls and whatnot ist gone. Why does that happen?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["debltlf"], "text": ["You're probably describing moire, which is the optical illusion you'll see when you see a grid through another grid. I'll not try to describe of explain it with words (it's difficult to, since it's a visual phenomenon), but have a look through this article, and it'll explain what you're seeing: URL_0"], "text_urls": [["https://en.m.wikipedia.org/wiki/Moir\u00e9_pattern"]], "score": [3]}}, {"q_id": "5wsb3n", "category": "Repost", "title": "What makes rape so traumatic? And why does it's emotional effects stick for so long?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["decl9np", "decl4s5", "decncjy", "decqp4j"], "text": ["There are a lot of factors to this. I'll talk about three of them. [Statistically]( URL_0 ), most rapes are perpetrated by someone the victim knew, not by a criminal leaping out of a dark alleyway at night. This betrayal of trust can hurt a lot. In addition, sometimes people will climax during a rape, despite their conscious wishes. This feels like your own body turning against you. The way rape is viewed culturally can also have an impact. \"Don't drop the soap\" jokes trivialize male rape victims' experience, and many people don't even think men can be raped. Legally, not every area recognizes this possibility, depending on how they define rape. Contrary to how it may seem in the media, female rape victims are still made to feel like it was their fault for trusting the wrong guy, wearing the wrong thing, drinking too much, etc.", "Intimacy and closeness are elements that affect multiple levels of consciousness. We are sexual beings from the moment we are born and experiencing closeness and intimacy from the way we interact with our care givers. Intimacy is hard wired into our brains and an assault and force within that framework is devastating because it's how we hold our self- esteem, self- efficiency, and sense of security. It's devastating to have that which makes us feel loved and close to be used as an angry and possessive act. It's a terrible to be a victim and incredibly difficult to stop feeling like one.", "I'm going to give you the benefit of the doubt and assume you're asking this because you genuinely want to know. Rape affects survivors on multiple levels. First, there's the physical aspect. It's usually a painful ordeal, even if the rapist doesn't engage in violence as a means to an end. Tissue tearing, bruising, fissures, and more. Then there is the mental and emotional toll. There is the abject humiliation. The fear. The degradation. Someone has taken your autonomy, they've violated you not just physically but violated your trust, they've robbed you of your sovereignty, inflicted their will upon you in the most intimate way. They've taken a piece of you. It is the ultimate breach of the boundary between your self and the outside world. Add to this the other ways in which it takes a mental and emotional toll on a person. Self-doubt and self-blame. Fear. There's abundant research to show many rape survivors experience PTSD. An estimated 1.3 million people have rape-related PTSD. But that isn't the only mental after-effect. Not by a long shot. Anxiety, depression, suicidal ideation. Fear. Previously unknown levels of fear. And it isn't just fear of being raped again. It's fear of the aftermath. Of getting pregnant, contracting a disease. Of how others will see you. Of being \"damaged goods\". Of how you'll be treated. Other long term outcomes include eating disorders, sexual dysfunction, alcohol and drug abuse, physical symptoms absent medical reasons, maladaptive beliefs, perceptions of lack of control, nightmares, night terrors, extreme social anxiety, and more. However it happened, whatever the outcome, you will be put on trial. Did you ask for it? Were you drinking? What were you wearing? How many relationships have you had? Were you popular in high school? What color were your clothes? Where were you? Why? Were there marks? Did you know the rapist? Had you had contact with them before? Do you flirt? Do you laugh in public? Have you ever enjoyed rough sex? Did you resist enough to count as a victim? Unlike ANY other crime, the effects of rape are traumatic in two major ways: first, the rape itself. Second, the reaction to the rape *from others*. In no other crime where you are the victim will you be made to feel like you did something to make it happen the way you will, with such vehemence, as with rape. In no other crime where you are the victim will you be made to feel like it is you who was the criminal. Additionally, it can take what *should be* the most intimate, loving act and turn it into something ugly and horrifying. It can take the very act by which we show love and attraction for our mates and make it a weapon used to destroy us from the inside. And then, when you're feeling the most alone it is possible for you to feel, some asshole will tell you you asked for it, or make a joke about it, or use it as a weapon with which to hurt you in an argument or tell you how damaged you are or how no one will ever be able to love you now. Do you see how that might be traumatic?", "From a female point of view, someone is forcing their way INSIDE your body. We all like to pretend sex can be casual and maybe for some it can be but truly at least for women we are letting you into our body. That isn't casual it's very intimate, the vulnerability in inviting someone to go there with you is partly why it's so intense. If we got all the same chemical and physical effects from thumb wresting it wouldn't be such a traumatic experience. One should certainly get to decide who does and does not get to be inside. To have that taken, to be broken into like with a battering ram or drugged till you cannot turn an intruder away. It's violent, traumatizing, embarrassing to have lost power over your own body. I know men are raped too, I'm sure there are facets I cannot fathom to that. Feeling a loss of control over ones own body as a male is likely equally upsetting. But in both cases deep down we are hard wired to physically express affection, acceptance, connection, passion and if we are lucky love through sex. To have that incredibly beautiful act overlaid with violence, disrespect, and degradation is a pretty upsetting thing to experience one that could very easily have long lasting emotional impact."], "text_urls": [["https://www.rainn.org/statistics/perpetrators-sexual-violence"], [], [], []], "score": [24, 9, 7, 5]}}, {"q_id": "5wsqpw", "category": "Repost", "title": "how are chip cards more secure than swipe cards?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["decphfq"], "text": ["The chips generate a rolling code and would be imposible to predict or duplicate. So suffice it to say that you cannot spoof the card. So unless you actually steal the card (easy to identify and report) you are out of luck. so any retailer that uses a chip is effectively immune from credit card fraud or atleast bogus claims of fraud."], "text_urls": [[]], "score": [8]}}, {"q_id": "5wsquw", "category": "Repost", "title": "the problem in the image, can the plane take-off??", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["decq9tr", "decpru9", "decpkpg"], "text": ["It's a trick question: something breaks, either before or after the plane takes off. Let's work backwards. If the plane has no air moving over its wings then it cannot take off. That much is true. If the plane is not moving relative to the ground then it does not have air moving over its wings and cannot take off. Again, a true claim. If the speed of the treadmill (backwards) matches the speed of the wheels (forwards) then the plane is not moving relative to the ground and does not have air moving over its wings so it cannot take off. This is as far as the (trick) question wants you to get, because once again we're left with a true statement. There's one final question to ask, though: can you set up the treadmill to match the speed of the wheels? In the question we just assume that this is true, but if we're starting from a false premise then we can't expect to get sensible results. It turns out that the question is \"no\" for this question, at least for most sets of simplifying assumptions\\* (things like neglecting friction). As you point out, the wheels spin freely. This means that you should be able to keep the plane from rolling backwards while sitting on a treadmill using almost no force (exactly zero if we completely ignore friction, but even in the real world bearings are very good and the rolling friction is very low). As soon as you start applying thrust on the 747 it tries to creep forward. The treadmill, attempting to keep the plane from rolling backwards. However, the treadmill doesn't slow the plane: it just makes the wheels spin faster. In response to the faster wheel speed the treadmill increases its speed, but again it is unable to slow the jet and just makes the wheels spin faster. This feedback loop rockets off towards infinite speed until the wheels shred or the treadmill breaks. Meanwhile the jet is still picking up forward speed, violating the assumption that the treadmill speed will equal the wheel speed. The jet moves forward, gets air over its wings, and takes off, or it would except that all of its wheels shredded their tires and subsequently their hubs as the treadmill broke the sound barrier a hundred times over, sending shrapnel into orbit. But hey, in the ensuing explosion caused by the exponentially accelerating treadmill I bet *some* part of the airplane would become airborne. ******* \\* I mentioned that the answer to that question is \"no\" when we make simplifying assumptions. Generally we'd look at the wheels as having no inertia of their own and as simply an interface between the plane and the ground with either zero friction or a friction that is independent of speed. In reality wheels do have a bit of inertia to them. Increasing the speed of the treadmill will impart a bit of force to the wheel (and thus to the plane) to increase the wheel's rotational speed. There's also some speed-dependent friction and if you could get the treadmill up to a sufficiently high speed then that could, in theory, hold the plane. In all likelihood these problems can be safely ignored as the speed or acceleration necessary to make them relevant are so far outside of the realm of practicality that the answer of \"you'd break things\" is still correct. The question evokes the idea of a treadmill that runs at roughly 747 takeoff speeds, but for these things to be relevant you'd need to be going well over the speed of sound.", "A plane does not use its wheels to accelerate. It produces thrust by pushing against the air, which in this scenario is not moving in any unusual way. The ground moving backwards as it contacts the wheels shouldn't matter since the wheels are not involved in changing the speed of the plane. The wheels would spin faster than normal since the ground is moving \"backwards\" and this could cause heat, stress, or even failures of the wheels. Whether these practical concerns would actually cause major problems is a question for a flight engineer (which I am not). But with an ideal plane working as intended, it won't make a difference.", "so if i understand the question, the conveyer belt is moving in the opposite direction of the plane? Planes generate lift by air flowing over and under the wings at different speeds, a plane can't take off if it isn't going fast enough for air to flow over/under the wings."], "text_urls": [[], [], []], "score": [10, 4, 3]}}, {"q_id": "5wss5g", "category": "Repost", "title": "Does Freedom of Speech in the USA grant the right to heckle your opponents?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["decplcs"], "text": ["The principle of freedom of speech only applies to the government. That's where the guarantee is, that the government won't be infringe our right to free speech. Individual people are not barred from heckling their opponents by the Constitution or the Bill of Rights. Human decency should limit heckling, but not the Constitution."], "text_urls": [[]], "score": [3]}}, {"q_id": "5wvbca", "category": "Repost", "title": "how are computer processors designed? Do engineers actually design it diode by diode?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ded5kkd", "ded696i", "ded69ol"], "text": ["First of all, the important component of a processor is the transistor. A diode simply allows current in one direction but not the other. A transistor can be thought of as an on/off switch for current flowing in one direction. Processing happens at a binary level. Ones and zeros in different arrangements mean different things, essentially different on off switches in sequence. Modern processors have a massive number of transistors to allow for the processing power we use in modern devices. Systems that use binary logic are described as digital systems. These types of systems are usually design from a top-level perspective, where the engineer has a function in mind such as memory and signal specifications. Then they decide how to arrange and connect the components to accomplish the task. Design of this level is all done on a computer with simulations to check if the design works because the materials the processors are built on are very expensive.", "No. There are libraries of existing designs for subcomponents that can be used. And these are often collections of subcomponents. Eventually you get to a point that was designed component by component, but those will have been designed by other engineers, many will have worked for different companies.", "No, they write a description of what the circuit is supposed to do using a *hardware description language*. They run that through a simulator to test its behavior before they commit anything to hardware. When they're confident it will work, different software converts the HDL code into a transistor layout. When chips were less complicated, this used to be done by hand by actually \"taping out\" a huge version of the layout that was then photographed and reduced, but no human could design a modern CPU like that these days."], "text_urls": [[], [], []], "score": [9, 4, 3]}}, {"q_id": "5wvocj", "category": "Repost", "title": "Why is W called \"double U\" when it is clearly \"double V\"?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dedb0e2", "ded794h", "ded8fqu", "dedae6i", "deddus4", "ded773r", "dedanz7", "ded9osb", "dedb139", "dedhd7p", "deda9bm", "ded97ga", "dedalpk", "dedh6lr", "dedbied", "dedbj0c", "dedfs9b", "ded6831", "dedjubd", "deddppz", "deduqw1", "dee5kc7", "dedb3o8", "deddme7", "dedk5a8", "dedgwbq", "dedahjp", "dedk7bj", "dedygtz", "dedwtdc", "dedh8v9", "dedk181", "dedbdhr", "dedhz14"], "text": ["When Old English was written, it used a mixture of Latin letters and older runes. One of these runes was Wynn, which was used to represent the wound that w gives today: URL_0 That runes was sometimes replaced by the combination uu - a double u - for the same sound. In german, the letter v changed in sound to be pronounced as f in most cases (it still is). In a few cases the v-sound was retained. To distinguish these cases, scribes began to write vv for these. When printing was developed in what is today Germany (and to some extent Italy, but that is less relevant here), the printing press manufacturers made types for the letters that they had. Since the combination vv was very common, they made a letter for it - w. In most languages letter is called \"double-v\". These printing presses and the letters for them were exported everywhere, including to England. The English quickly realized that they didn't have types for all their letters, so they made do with what they had. Since English didn't have the w before printing, they simply reused that letter for the Wynn rune, which was missing. It is called \"double-u\" because it was also sometimes written as \"uu\" Similar story for the letter Thorn, which was also missing when printing and became the \"th\" combination. URL_1", "In the 7th century, the old English language was starting to be written in the Latin alphabet, but it had a sound that the Latin didn't, the W sound. To get around this, they doubled the U symbol to represent it. The following century, the \"uu\" digraph was replaced with the \u01f7 (wynn) rune. This died out after a while and in the 11th century, the Norman (French) scribes reintroduced the \"uu\" digraph as a single, though jointed instead of curved, character, the \"w.\" Source: URL_0", "In French \"w\" is called \"double v\". I wonder how it ended up like this, and what other languages call it.", "I'd rather want to know why English went with \"double-u\" instead of something like \"Wee\". It works perfectly fine that way in other languages.", "At one point, U and V were not regarded as different letters (and in fact, F, U, V, and Y are all ultimately derived from the same Phoenician letter). You may be familiar with this to some degree if you've ever seen a picture of [a Roman inscription like this one]( URL_3 ), whose first two lines read *senatus populusque romanus*. A holdover of this usage appears in the [branding of some Italian luxury products]( URL_1 ). UU and VV, the ancestors of modern W, were similarly interchangeable. In Middle English (during the Middle Ages), the pointed V was used at the beginning of a word, while the round U was used elsewhere. As time went on, English and other languages began assigning more discrete, well-defined roles to what started off as two visual representations of the same letter. By and large, V has become a consonant and U has become a vowel, but W is a bit of an odd case. The [w] sound it makes in English is a kind of consonant often referred to as a \"semivowel\". In German, it is strictly a consonant (representing [v]). In Welsh, W is a vowel. It is also [a word]( URL_0 ) in Welsh, and you can even put an accent mark over it, like in [the Welsh word for 'water']( URL_2 ). Whether you call it \"double-U\" or \"double-V\" varies from language to language. In upright type, it tends to have a pointed appearance, but in italics (as in cursive handwriting), many typefaces give it a more rounded look, a relic of when it was written *uu* in a calligraphic hand.", "Originally, U and V were just different ways of writing the same letter, a bit like a and & #x1d4b6;. Later they became separate letters, but the name of W didn't keep up with the change. Some languages do call it \"double V\", though, and w is sometimes written as & #x1d4cc;.", "In spanish it is \"double V\" doble ve. URL_0 URL_1 EDIT: apparently it depends on where in spanish-speaking-land you are. It may be double you, or double vee.", "W is the only letter you could \"spell out\" as a word without using the actual letter itself. 4th dimension stuff, I know. Edit: lol. If only all this processing power was used for good. Nice work all. The podcast I heard this on didn't think of any others.", "> when it is clearly \"double V\" That depends on the font used. I learned to hand-write \"W\" with curves rather than angles. Most computer-based fonts use a more \"V\" looking shape.", "Funny thing I've noticed about these odd letters... #**Italian** For example, the Italian alphabet has only 21 letters. It does not have J, K, W, X, Y. They do, however, often know those letters and use them to make a name sound exotic! You would often see that in small business, where the business owner wants to create a sort of foreign 'intrigue' and appear different or exotic. One way is to spell your name with one of those funny foreign letters - often a \"W\" or a \"K\". In Italian, the letter K's work is done by \"CH\" - pronounced as the English K. You can still find the word 'Yacht' in an Italian dictionary - the only entry with the letter 'Y' and practically the only word I know in Italian that does not end with a vowel. **Polish** There is a similar story for Polish where the Polish alphabet does not have the letters \"Q, V, X\". An exotic name for them would begin with a 'V' for example. EG: Viktoria instead of Wiktoria. **Spanish** Spanish says \"Double V\" (*'doble ve'*); while Italian does not have this letter at all and it is rare in French mostly reserved for foreign words. This is somewhat surprising as otherwise, Italian and Spanish are often so similar they are often mutually intelligible if spoken very slowly.", "F, U, V, W, and Y are all descended from the same Phoenician letter, *waw*, and they branched off at different points (and ended up making different sounds in different languages). In Latin, the W and U sounds were made with a V (remember, vini vidi vici is pronounced \"winy widy wicky\"). And Latin was the alphabet that mattered. But the V had started to be pronounced like a V, so people needed a letter to do what V had formerly done. So, W is actually a doubling of the letter that made the U sound, V.", "While it is most commonly seen as w, or two v's, when I was a kid I was taught to write it as a double u, meaning it was curved and didn't have those points that make it a v. Also in cursive it's written as uu", "The \"U\" as we know it as a more modern version of the Roman \"V\" which represented our U and W. In earlier versions of written English before spelling was more standardized, U and V could be used interchangeably, but would most often be reversed from their modern usage. It's not uncommon to see \"Uery Trve uirtve\" instead of \"Very true virtue.\" Essentially, the name \"Double U\" stuck from this time period, but the usage of the letters changed. EDIT: My source for this is anecdotal, but I have an English degree and have read A LOT of texts using outdated spellings.", "So the add-on question. Why isn't 'm' called a 'double n' ?", "In French it's pronounced as the equivalent of \"double v\", even if you type double u in google translate it comes out as double v in French.", "So I took a years worth of Latin a while back and there is a letter, \"v\" which in latin is easily confused with the other letter in latin, \"v\". Whereas the letter \"v\" is familiar to a modern speaker, as in the word \"very\", the letter \"v\" is not so familiar because it is pronounced with more of a \"w\" sound, so in Latin a \"v\", as in \"veni, vidi, vici\" (Caesar's famous quote) is pronounced \"weni, widi, wiki\" (the \"c\" in Latin is hard, but began to change around the time of Cicero to a soft \"c\"). It can be wery confusing for a learner of Latin, so our course (the Oxford course- not the school, its a curriculum) preferred that in cases where the latin \"v\" was to be pronounced as a \"w\" we should just write a \"u\". Based on this I like to imagine that the \"w\" is really just an adaptation of the Latin alphabet's letter \"v\" (\"u\") ( < ---- thats not supposed to look like a face.) edit: here's a [wikipedia link]( URL_0 ) that might be interesting.", "Isn't it normally written as double-u when handwritten? That's how I write it.", "Well, it was double-u back when the shapes of U and V were switched up, I believe. I was reading an excerpt of Genesis for an English assignment, and both letters were swapped.", "Am I the only person who writes my W's rounded? So essentially I'm writing double U", "Not an explanation because I'm not sure - but a protip: when talking to a Scandinavian language native, often when they say \"V,\" they mean \"W.\" I've had a few interesting conversations about motorcycles with coworkers where they talk about the \"VR450\" when they are talking about the \"WR450.\" It can get very confusing very quickly.", "In all fairness, while in English it does make little sense, in other languages, they did get it right, like German, they call it double-v or something. But at the same time, when written softly, or in other type faces, it can look like a double u, and not like Vs. I had a friend in primary school who always wrote it is a double u, and never with corners. meh", "UUhere did you learn to uurite your uu's?", "forgetting the technical explanations, lower case W's are normally like uu when written by hand", "In the french language, this is exactly how we describe the letter \"w\". The direct translation means double v.", "Am I the only one never thought of W as \"double U\" Lol took me quite sometime to figure this out", "Despite good historical justifications, I propose a movement where we begin calling it a double V. Hell, that can be the name of the movement.", "a lot of historical talk here, but... is nobody aware that different fonts exist? [this one]( URL_0 ) is clearly a double U, not a double V", "In Italian, it's called doppia vu which just means double v. I used to hear on the radio where the DJ would shorthand websites www as vu vu vu.", "It's called double V in French but in the last 18 years of my French education life i don't ever recall reading a French word with W in it.", "In portuguese we say \"Double V\" (Dobre-v\u00ea), but its so ugly that nowadays everyone says \"Da-blee-u\" which sounds a lot better when u r spelling any website ( URL_0 )", "Different languages call \"W\" different things. In French it's \"Double Vay \", in Italian, it's \"Doppia Vu\". (Pronounce the French version Doobleh). As noted, there is probably a source that is very old, coupled with the exigencies of needing ways to print sounds that were either written out or handed down orally in the traditional fashion.", "In fairness, a lower case W is w, and when written BY HAND: the lower case version tends to look like it has two curved u's in it. If that makes any sense at all. Not sure about the origination of the way we say our letters but, especially in cursive; it definitely looks like two lower cased U's.", "Look at the sounds. The w sound is basically the \"oo\" vowel sound turned into a consonant, so it makes sense why they would call it that. Plus originally I think it was actually made with two u's, like uu, and it became easier to write is as two v's. Now what I'd like to know is why in German, Polish, and I believe other languages, w makes a v sound.", "Despite we don't use the letter in Portugal, when talking about it, even in school, I always heard it being pronounced as something like double U, but also very often as double U V. So I consider this very interesting to see what you all think about it. Personally I think the double V makes more sense, but I also understand that it all depends on the history of the language or perhaps cultural influences."], "text_urls": [["https://en.wikipedia.org/wiki/Wynn", "https://en.wikipedia.org/wiki/Thorn_(letter)"], ["http://www.grammarphobia.com/blog/2011/04/double-u.html"], [], [], ["https://en.wiktionary.org/wiki/w#Welsh", "https://en.wikipedia.org/wiki/Bulgari", "https://en.wiktionary.org/wiki/d%C5%B5r", "https://upload.wikimedia.org/wikipedia/commons/4/40/Arch.of.Titus-Inscription.jpg"], [], ["http://www.spanish411.net/images/Infographics/Spanish-Alphabet.jpg", "http://www.spanish411.net/Spanish-Alphabet.asp"], [], [], [], [], [], [], [], [], ["https://en.wikipedia.org/wiki/V#Descendants_and_related_letters_in_the_Latin_alphabet"], [], [], [], [], [], [], [], [], [], [], ["http://1stwebdesigner.com/wp-content/uploads/2012/10/30.jpg"], [], [], ["WWW.google.com"], [], [], [], []], "score": [11847, 1054, 900, 282, 252, 106, 64, 44, 41, 29, 27, 18, 16, 14, 13, 9, 6, 6, 4, 4, 4, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3]}}, {"q_id": "5wy5sk", "category": "Repost", "title": "If melting ice in a glass of water does not change the water level, why would glaciers at our poles?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dedpr76", "dedr82b", "dedq6eq", "dedpxub", "dedprpp", "deduo4y", "dedq2ym", "dedprfj"], "text": ["Ice *in water* melting does not change the water level, because the ice is already displacing the same amount of water as it would do when liquid. The problem is ice *not* in water. For instance covering the landscape of the continent of Antarctica. When that ice melts, it flows downhill into the ocean, which rises because it now has more water in it.", "To add, ice reflects radiant heat at wavelengths that can penetrate our atmosphere and out into space. Without ice, the exposed land and waters will absorb that heat. The heat can be radiated out again, but it will be at wavelengths greenhouse gases will absorb and trap in the atmosphere. The loss of ice makes the Earth hotter *faster*. Edit: Think *planet Venus*.", "Wow I just posted this and already there's a lot of great responses! So what I'm understanding is the main factor to rising water levels will be Antarctica, and the Arctic will have little to no effect. Thanks for all the responses, and let's hope we don't have to see this experiment acted out in real life.", "Glaciers are on land, not floating in water. So they are not displacing water. So when they melt you are just adding water to the oceans thus raising their level.", "Antarctica is a continent. It is land and ice sitting on land does make a difference in water level. So do glaciers on land elsewhere in the world.", "First, ice on the land (Antarctica) will melt and run into the oceans. This isn't ice in a glass melting, this is ice from the tray in you freezer being added to the glass. Second, it's a feedback loop. Ice reflects the Sun's rays back into space. Water is much darker and absorbs a lot of the Sun's heat, then slowly releases it back out in another form that gets trapped by the atmosphere. Ice is not only a result of a cooler Earth, but a cause of a cooler Earth. Less ice means the planet will warm up more. (This is called the Runaway Greenhouse Effect, and could theoretically boil away the oceans if we raised the average global temperature by about 34\u00b0C/61\u00b0F.)", "While melting the glaciers that are floating on the water or submerged in the water would not change the level of the ocean (or at least not significantly due to density differences with salt water ice), we need to also account for the ice on solid land melting and flowing into the ocean. [source]( URL_0 )", "The ice in Antarctica is on land, mostly, so when it melts, it's only adding to the ocean volume."], "text_urls": [[], [], [], [], [], [], ["http://smithplanet.com/stuff/iceandwater.htm"], []], "score": [97, 15, 10, 8, 7, 6, 5, 4]}}, {"q_id": "5wyjtx", "category": "Repost", "title": "Why and how do we get dark circles under our eyes when we don't get a lot of sleep?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dedv5gg", "dee1dkz"], "text": ["If you don\u2019t get enough sleep or you\u2019re always stressed out, your body will produce more cortisol in an effort to keep you alert. Over time, cortisol can constrict blood vessels or, in this case, dilate them and make the ones under your eyes bigger. Allergies can be a major cause as well. Allergic reactions cause your body to release histamines, which also dilate blood vessels. Also, sunlight can damage the skin cells around your eyes and kill them off if you don\u2019t protect your face. Less skin cells means thinner skin, which means darker circles. And lastly, as you get older, you have less fat underneath the skin and it gets thinner. (source: URL_0 )", "In my experience (I'm not a doctor or a beauty therapist) but I used to have horrendous black circles until I read an article about dehydration and skin issues. I read; The skin on the face is very thin, which is why we gain and lose weight on our faces so noticibly and when we drink too much water we get 'water bloating' on our face. The skin under the eyes is very thin so it's the first spot to show any dehydration in the skin. If you personally suffer with eyebags try getting 40 winks and drinking the right amount of water. * I knew a girl who used sleep with her propped up and eyebags on each night to keep her eyes hydrated. I alwayd told her she didn't need them and she would tell me \"that's exactly the point! They work!\""], "text_urls": [["lifehacker.com"], []], "score": [19, 3]}}, {"q_id": "5wz5gd", "category": "Repost", "title": "Why do different types of alcohol, such as beer vs vodka vs whiskey, produce a different feeling of being drunk?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dedzmct"], "text": ["Alcoholic beverages contain substances called congeners. These substances include small amounts of chemicals such as methanol and other alcohols (known as fusel alcohols), acetone, acetaldehyde, esters, tannins, and aldehydes. Different types of liquor have different amounts and types of congeners based on how they were made. This is partly responsible for the taste and aftertaste of the alcohol as well as contributing to the felt hangover effects. As far as different liquors producing different \"moods\" or kinds of being drunk (ie, \"whiskey makes me angry and violent, tequila makes me happy and flirtatious\"), that is entirely inside your head and either the result of social pressure or confirmation bias. Ethanol is ethanol is ethanol. It all does the same thing to the body and the brain. If a certain kind of liquor makes you feel like you get more angry or more touchy and flirty, that is just your own preconceptions and social pressures acting subconsciously to make you more prone to acting like that. There is nothing different about the liquor that makes you act or feel one way over another. It's just in your head."], "text_urls": [[]], "score": [4]}}, {"q_id": "5wz9mt", "category": "Repost", "title": "What is bad about a country being in debt? US is in debt trillions and they seem to be fine.", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dedzo22", "dedzr4n", "dee0s0a"], "text": ["It's bad if your country is unable to make the payments it has set on its debts, because then other entities will decide it isn't safe to lend you money anymore (since they aren't getting it back as agreed) and won't want to do so. That takes away a valuable tool for funding activities in your country, limiting you to cash on hand. If you *can* make the payments, then it is not necessarily bad at all. But it does *sound* scary to many people, and so politicians will still use it as a scare tactic.", "There is nothing wrong with being in debt as long as you can pay what you owe on time. Anyone with a mortage, car payments, students loans are also in debt, but they pay their payments on time so the banks trust them, With a country its no different.", "These previous posts might be helpful, this is a common question: URL_1 URL_0 URL_2"], "text_urls": [[], [], ["https://www.reddit.com/r/explainlikeimfive/search?q=title%3A%28US+debt%29&amp;restrict_sr=on&amp;sort=relevance&amp;t=all", "https://www.reddit.com/r/explainlikeimfive/search?q=title%3A%28national+debt%29&amp;restrict_sr=on&amp;sort=relevance&amp;t=all", "https://www.reddit.com/r/explainlikeimfive/search?q=title%3A%28U.S.+debt%29&amp;restrict_sr=on&amp;sort=relevance&amp;t=all"]], "score": [7, 6, 4]}}, {"q_id": "5wzo62", "category": "Repost", "title": "Why do countries have different power outlets & sockets when they could share one universal standard?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dee3g5f", "dee3b4o"], "text": ["When countries electrified, they were much more economically isolated from each other than today. They built up their electrical infrastructure from scratch, and their specific needs, resources, and arbitrary choices led to some differences from country to country. Over time, other industries built up around using that country's standards - e.g., consumer products needed to have cords that fit the sockets. So there is a lot of money and existing infrastructure invested in a given country's system. Unifying standards worldwide would save money in the long-term, but in the short-term a lot of businesses would have to invest to change their infrastructure and product design. Governments could subsidize the transition, but there is not much political will to pay for such drastic changes for the sake of long-term savings.", "Each electrical system grew independently. Frankly it's amazing that there are so few given the number of electrifying governments/companies that sprung up around the same time all over the world. The answer why they do not switch to make things easier for you is because they do not care about you. Tourist's struggling with adapters is a tiny problem compared to rewiring whole continents of electric customers."], "text_urls": [[], []], "score": [7, 4]}}, {"q_id": "5x0zxt", "category": "Repost", "title": "What exactly is going on when food feels like it's \"going down the wrong hole\"?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["deeepri", "deeh7fy"], "text": ["You have two \"holes\" one leads to the esophagus, where food is supposed to go, the other leads to the trachea where air is supposed to go. When foreign objects (food, water, etc) go down towards the trachea there are tons of highly sensitive nerves that detect this and initiate the cough reflex to try to get it out. Your airway is sterile and does not like any foreign objects there as they can cause infection and block the airway, so you will cough and cough until the foreign object is expelled.", "You breathe through one hole and you eat through the other. When you eat food and it misses the food hole it hits the breathing hole. The breathing hole has an alarm system on it that prevents food from going in it. When food gets too close it trips the alarm and all the air in breathing hole comes out in a blast to get all the food out of the way. Sometimes it takes a few blasts to clear the food. All that blasting is called coughing and its just your body trying to keep air in the right hole and food where it belongs."], "text_urls": [[], []], "score": [10, 4]}}, {"q_id": "5x26me", "category": "Repost", "title": "Why does the US debt keep going up? Will it ever be repaid? Will China ever stop lending?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["deenszz", "deeo47y", "deeopkd"], "text": ["Your understanding of the basic situation is off. Most years, Congress allocates more spending than the projected tax revenue, which means the US must issue bonds to make up the shortfall. There's no requirement that Congress pass a balanced budget, and they routinely don't. Also, the executive branch has basically no control over spending, Congress has eliminated most of the opportunities for discretion. If Congress allocates a certain amount of money for a purpose, the department in charge of that has to spend that much money, they usually can't choose to spend either more or less. As far as the sustainability of this, note that governmental finances are significantly different than private finances, so trying to treat them similarly is a bad idea. First, the US government can borrow money extremely cheaply, often below the rate of inflation (the current interest they pay on a ten-year bond is 2.36%; a year ago it was 1.75%), which means that effectively investors are paying the US government to borrow money from it. Second, unlike a private party, the US government is in control of both its revenue and its spending. That means that it's very unlikely to be unable to pay off its debts, because it can raise taxes to bring in more money if it feels the need. Third, the US government doesn't need to be time-limited in its outlook. If taking on more debt today means that the country is better off in the future, that's a fine tradeoff to make, because the US government doesn't need to plan for retirement or save up to buy a house or worry about dying or any of the other things that cause regular people to modify their finances. The US is nowhere near being unable to borrow. The interest rates they pay are so low because US Treasury bonds are considered among the safest investments in the world. Something catastrophic would have to happen for the US to default on its debt.", "This is not a direct answer to your question but just a correction of one of your assumptions. You mention China assuming (as many people do) that borrowing from China is significant. This is not the case. The US national debt is about $20 Trillion (2016). Of this Japan and China each hold about $1 trillion each. That is only 5% of the total debt so China is not the biggest lender by any means. The overall debt breaks down (very) roughly as follows: * Intragovernment holdings: $5.5 trillion (mainly government trust funds & retirement funds) * Public held debt: $8.0 trillion (federal reserve, mutual funds, private pension funds, banks, insurance, private investors) * Foreign governments & investors: $6.5 trillion (China, Japan, Ireland, Brazil, Switzerland, UK, etc) So most of the money is owed to organisations both private and public within the US. They in turn get their money from the American public as investments, savings, pensions etc. More information [here]( URL_0 )", "We had a huge surplus until the Republicans got in control in 2000. They went from having a $200 billion surplus, plus another $150 billion surplus in Social Security, every year. But they spent, and spent, and spent, but never raised any taxes to pay for it. They gave huge tax cuts to the rich, that we have to borrow money to pay for. They did this both in 2001 and 2003. Tax cuts, but didn't pay for it, this means borrowing to give rich guys tax cuts, and they are about to do it again. Also, they gave a huge prescription drug benefit, without paying for, for Medicare recipients. While this may sound nice, without paying for it, it bankrupts the Medicare trust fund. So Obamacare make the rich pay more, so Medicare won't bankrupt as fast, and the Republicans want to repeal it giving billionaires an $11 Trillion dollar tax cut over the next ten years. Had we stayed on the path that President Clinton set out for us, we would have paid off our debt in 2012. Instead we got huge tax cuts for the rich, huge medicare benefit not paid for, and two wars that cost over $1.5 Trillion so far. Now they want more tax cuts, which means higher deficits and more borrowing. If interest rates get up to 4%, we will be Greece and unable to service our debt. Do the math, there is a huge difference between 2% interest on $20 trillion and 4% on $20 trillion of debt."], "text_urls": [[], ["https://www.thebalance.com/who-owns-the-u-s-national-debt-3306124"], []], "score": [11, 5, 3]}}, {"q_id": "5x31j9", "category": "Repost", "title": "Why do scientists immediately dismiss alien life if there is no oxygen? How do we know that other life needs oxygen versus any other chemical to live?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["deet29l", "deeth13", "deetr5z"], "text": ["Quite simply, we know for a fact that life can exist in the conditions we live in now, so that is what we search for. We don't know for a fact if life can exist in other ways so there is no point looking. We look for what we know works, not guess and look blindly. Edit: by no point looking I mean, we've already got millions or billions of planets just within the scope of our life needs to look through, adding worlds that could support life if they had other needs than oxygen would just make the task impossible.", "The main reason we're looking for life *at this time* is to answer the \"are we alone\" question. To that end, our search focuses on finding life **as we know it,** because it's familiar; we know it's possible for life to flourish under Earth like conditions. We don't know how likely it is for life to exist in different environments, and we don't have experience in recognizing it. That being said, liquid water is more indicative of this than oxygen. Many microorganisms are anaerobic. It's not that the possibility of life is dismissed, but that we don't know how likely it is to exist in other environments - we are choosing familiar targets first due to limited resources available for the search.", "There are simple organisms living on Earth right now that do not need oxygen to live and will actually die in the presence of it. Source: URL_0"], "text_urls": [[], [], ["https://en.wikipedia.org/wiki/Anaerobic_organism"]], "score": [14, 11, 3]}}, {"q_id": "5x3oe7", "category": "Repost", "title": "I know that we get vitamin D from being in sunglight but how?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["deeye4k"], "text": ["There's a molecule in that your body uses to make cholesterol called 7-dehydrocholesterol (let's call it 7D). 7D that gets exposed to the UV-B light emitted by the sun or tanning bed is converted into vitamin D3."], "text_urls": [[]], "score": [4]}}, {"q_id": "5x49g6", "category": "Repost", "title": "why is 'turning it off and on again' a fix-all for so many technological problems?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["def3hhe"], "text": ["Have you ever done a really complicated math problem and gotten lost half way through? Sometimes you can fix your mistake, but sometimes you just need to scrap it and start all over. A computer program is just a really, really complex ball of math. If there's a mistake somewhere, sometimes the only way to get things working again is to start all over from the beginning."], "text_urls": [[]], "score": [5]}}, {"q_id": "5x4mth", "category": "Repost", "title": "National debt, is there even enough money to pay it all off", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["def63eh", "def6l9r", "def6lzh", "def6hdg"], "text": ["Why would you think these debts are insurmountable? The US, for instance, has absolutely huge numbers in its debt, yet it is successfully paying it off. It doesn't 'go away' because the US pays off some debts and accrues new ones. It is not a goal of the US government to reach \"0 debt\" because this doesn't offer a lot of particular tangible benefits.", "First thing to remember is that most money is imaginary. Debt is really just an agreement to pay off a certain amount of money eventually, and so long as you continue to pay interest on that loan, everything is fine. Nations aren't actually interested in debt being paid off, as the endless paying of interest is actually more profitable for them. So, there doesn't have to be enough money to \"pay off a loan\" so long as governments can afford to keep paying the interest on all those loans. This is why Greece almost collapsed, because they couldn't afford those interest payments anymore.", "Do your parents have enough money to pay off their mortgage? Probably not. They make payments on the interest and pay down the balance regularly. If they couldn't do that or didn't want to do that they might sell the house and that money would pay off the loan.", "There are a lot of agencies that track national debt health, and almost all of them are quite healthy, the United States included. The US has a debt-to-gdp ratio of 104%. That means that it owes 104% of it's annual income in debt. So, it's comparable to someone who just bought a $31,200 dollar Ford pickup truck with a few features who makes $30,000 a year. Something people do in their lives all the time. Now, the fact that it's ever-increasing is, in the long term, a little concerning. But it's not really concerning in the immediate or unsolvable sense. The US can afford to wait on the global economy to be in boom times to raise taxes and/or cut spending to balance the budget."], "text_urls": [[], [], [], []], "score": [4, 4, 3, 3]}}, {"q_id": "5x51wd", "category": "Repost", "title": "Why do Britain and other English empire countries still bow to monarchs? What real purpose does the queen serve?", "title_urls": {"url": []}, "selftext": "I just read the entire Wikipedia entry on Elizabeth's reign, and it seems like she does almost nothing at all. She goes on tours, gives speeches, holds dinners, and gives her opinion on certain matters. Of her accomplishments, the only things I can find read like \"The Queen's composure and skill in controlling her mount were widely praised.\" Or \"the Queen's \"calmness and courage in the face of the violence\" was noted.\" To me, an American, it seems ridiculous that anyone would respect such a person. Nonetheless, when I make fun of her on Reddit, lots of people rush to Elizabeth's defense. They seem very offended. I suppose she is a symbol for their culture, but why? Her office is completely unnecessary. Is it just because they don't want to change the old ways? Is there more to it than that? I just don't get what all the fuss is about. To me, she is an old bat in a silly hat.", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["defbvy5", "def9yu8", "defa09d", "defn592", "defpb34", "defcoxz", "deffuy4", "defocda"], "text": ["The monarch is head of state, as opposed to head of government (that would be the Prime Minister); in European republics, the monarch is usually replaced by a President, who may have more definite powers and is either directly or indirectly elected. The head of state basically represents the country, while the head of government sets the broad agenda for the legislature and also chairs the cabinet. The US President effectively combines the roles of head of state and head of government, which is sometimes problematic in terms of diplomacy: a recent petition (signed by 1.8 million people) called on the government not to accord President Trump the honour of a full state visit due to controversies surrounding his conduct as head of government. In the last few centuries, the role of monarch has declined, and since Victoria has kept out of party politics altogether -- in public, that is. In private, she has regular audiences with the Prime Minister in which they talk of matters of state. In theory, the most important role the British monarch has is to ensure good governance, but it's unclear how much she can actually do to that end. It's also unclear just how much influence she does have on government policy, since the details of her meetings with the PM are confidential. It is known that Margaret Thatcher, a Conservative, once complained that if the queen could vote, she would vote Liberal Democrat. The murky nature of her exact role, given that she is unelected and accountable only to constitutional law (whatever that may be on a given day), obviously makes a lot of people nervous. On the other hand, given her very long reign (her first Prime Minister was Winston Churchill), her experience may well be extremely useful. Diplomatically, she performs a role that is arguably very important. As head of state, she meets other heads of states, and that certainly helps to oil the complex machinery of international relations. It may be helpful that, since she is a hereditary monarch, she doesn't have to toe the party line or keep one eye on her approval ratings.", "She's like a living historical monument to all of the monarchs that have ruled before her. You also have to remember that the monarchy creates an additional \u00a3300 million/year for the UK. Maintaining the monarchy costs the UK about \u00a350 million/year, BUT because of a hundreds of years old agreement, the monarchy owns land that it lets the UK government collect rent on to the tune of about \u00a3350 million/year.", "Probably because of the following: \"The monarch and his or her immediate family undertake various official, ceremonial, diplomatic and representational duties. As the monarchy is constitutional, the monarch is limited to non-partisan functions such as bestowing honours and appointing the Prime Minister. The monarch is, by tradition, commander-in-chief of the British Armed Forces. Though the ultimate formal executive authority over the government of the United Kingdom is still by and through the monarch's royal prerogative, these powers may only be used according to laws enacted in Parliament and, in practice, within the constraints of convention and precedent.\" [Sauce]( URL_0 )", "She had a lot of diplomatic duties. She meets with foreign leaders and dictates broad policy. The Queen is basically the face of Britain. She represents her country in the global scale. She also has religious duties as the head of the Church of England. And she has the public eye. She's basically the world's most famous celebrity. It's a power that can be used to a very strong effect if done right. Like if the British Parliment decides to pass a law she strongly objects to, all she has to do is say something. She can't legally stop it, but she is respected enough that going against her wishes would cause a massive public backlash. So she can use this to subtly influence policy by persuading voters to weigh in on things she wants done or undone.", "In simplest terms, here's the British Public's relationship with the Queen: We agree to do whatever she says, as long as she agrees to never actually tell us to do anything. As for what actual role the Monarchy actually performs, the Queen is a figurehead, similar to an Ambassador. If a world leader visits the UK and is invited to an audience with the Queen, it's a show of respect. The other part is basically tradition. they're a huge tourist draw and a merchandising empire. They generate about \u00a3500m a year for the UK through tourism alone.", "[Australia had a government shutdown once. In the end, the queen fired everyone in Parliament.]( URL_0 ) It's her royal prerogative as head of state to dissolve Parliament if it's in that country's greater interest. It's the ultimate in checks and balances / separation of power.", "It is all ceremony and tradition, a way to keep in touch with the grand thousand year history that has revolved around the British Monarchy. The British follow royalty like Americans follow Kardashians, there doesn't have to be much point to it. The monarchy exerts almost no real political power, and should it try to exert what little powers it had against a Commonwealth member's wishes, the country would almost certainly leave the Commonwealth. In practical terms, the monarchy is a significant tourist draw, and by some analyses, it pays for itself.", "I'll take Sweden as an example. Our king has no real power. He serves only a purpose of representing the country. In the constitution, he is referred to as \"ceremonial power\", to give you an idea. So I guess it's more of a patriotic thing, that honnoring the monarchy is like honoring the history of the country. The only real power he has is to accept the letters of credence (basically authorising the ambassador to be in the country for a diplomatic purpose) from foreign ambassadors coming to Sweden, meaning that in theory he could refuse a person coming for diplomatic purposes to stay in the country."], "text_urls": [[], [], ["https://en.wikipedia.org/wiki/Monarchy_of_the_United_Kingdom"], [], [], ["https://www.washingtonpost.com/news/worldviews/wp/2013/10/01/australia-had-a-government-shutdown-once-it-ended-with-the-queen-firing-everyone-in-parliament/?utm_term=.b79d4b07eb65"], [], []], "score": [36, 15, 11, 9, 7, 6, 5, 3]}}, {"q_id": "5x56ub", "category": "Repost", "title": "What is sleep paralysis and why do we 'get' it", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["defb1xj"], "text": ["When your brain goes into sleep mode, your nervous system sort of \"shuts down\" your body's responses to brain signals. This is because if it didn't every time you did something in a dream, your body would do the same and you'd injure yourself. So when you're dreaming about running, your legs don't (usually) flail around in bed, for example. Sometimes, when you're in a state where your brain is on the verge of or just into sleep, but you're still aware, your body may not respond to your brain's signals because your body is basically in \"sleep mode\". More reading here: URL_0"], "text_urls": [["https://en.wikipedia.org/wiki/Sleep_paralysis"]], "score": [3]}}, {"q_id": "5x6j82", "category": "Repost", "title": "4th dimension", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["defosme"], "text": ["Dimensions are how many numbers you need to identify a point. In our normal 3D space, you need 3 numbers to describe any point. For exapmle: * (latitude, longitude, altitude). * Or you can describe where your lamp is compared to where you are by saying something like (turn 40 degrees left, 10 degrees up, then go 5 feet forward along that line). In 4D you need 4 numbers to uniquely identify a point. In physics, time is often described as the 4th dimension. If you describe the location of your lamp, you have to give a time number too. The lamp wasn't always there, so you have to specify the location in time as well. In more advanced physics, you *must* consider both space and time together to make sense of the universe. ____________________________________ BTW you don't have to be describing *physical* space. For example if you are measuring temperature at any point on earth, you are working with a four dimensional space. Specifically the four numbers you need are (lattitude, longitude, altitude, temperature). In fact there don't need to be any physical aspect at all. For example, colours in computers are often described with three numbers (r,g,b), where r describes how red the colour is. g and b do the same for green and blue."], "text_urls": [[]], "score": [8]}}, {"q_id": "5x6mpr", "category": "Repost", "title": "If I dug a hole to the other side of the world like Bugs Bunny, and jumped in it, would I come out the other side or would gravity do something weird around the center?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["defnyid", "defo5d6", "defonal"], "text": ["In theory, and this is assuming that you don't get burnt up by the heat of the planet, and this hole doesn't automatically fill with water and magma and doesn't take the planet apart or anything of that nature, and ignoring air resistance, you'd fall through to the other side, slow down, and start falling at the same height above ground there as you did here. And it'd be about 42 minutes of constant falling. In reality, other than all of the ways you'd be dead, if we consider air resistance you'd probably hit terminal velocity relatively quickly, so you likely wouldn't make it to the other end, just bounce around in progressively smaller and smaller steps until you stop at the centre of the earth.", "(Sidenote: There *must* have been a show that had this recently. This is like the 5th post asking this question.) Anyway, assuming: * the tunnel sides don't crush under the pressure deep in the Earth, * you don't burn to death * Earth isn't rotating, so you don't bump into the side of the tunnel * Earth is perfectly round * there is no air (or other source of friction) Then yes, you would pop out the other side of the Earth in approximately 40 minutes. Gravity would switch directions once you get past the centre of the Earth, but you'll have built *exactly* enough speed to be able to get to the other side.", "If the hole contains a vacuum, and we can ignore air resistance: You come out of the hole on the other side of the planet 38 minutes and 11 seconds later and at exactly the same speed at which you entered the hole. You would achieve a maximum velocity of around 18,000mph during your trip. If the hole contains air: You reach the terminal velocity of a free-falling human (around 125mph) after the first 15 seconds and then continue falling for another 32 hours or so until you get to the center of the Earth, at which point you yo-yo back and forth for a bit before coming to a stop."], "text_urls": [[], [], []], "score": [16, 9, 4]}}, {"q_id": "5x6mw3", "category": "Repost", "title": "Why do we hiccup?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["defsdxr"], "text": ["There's not much of a 'reason' as to why we hiccup. Hiccups are caused by involuntary contractions of our diaphragms, the muscle that allows us to breath. These are pretty much just 'twitches', and there's no scientific reason why we hiccup once in a while."], "text_urls": [[]], "score": [3]}}, {"q_id": "5x6sxy", "category": "Repost", "title": "If a hole was drilled so that it passed through the exact center of the earth, would an object dropped through that hole \"float\" at the center due to gravity on all sides?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["defq2an"], "text": ["Assuming you hollowed out a protected space free from heat, pressure, and all other factors, then: If it was placed there, yes. If it was dropped there, no - it would oscillate around the center with a strange periodic motion due to the increasing gravity off center."], "text_urls": [[]], "score": [4]}}, {"q_id": "5x6tu9", "category": "Repost", "title": "How do we not lose data when compressing text or software files into .rar or other zipped formats?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["defqjx9"], "text": ["There are many different types of compression. Some types of compression do discard data, but others do not. Compression that discards data is called **lossy** compression. Compression that does not discard data is called **lossless** compression. Video, audio and image compression is generally lossy. You can discard a surprisingly large amount of data before it can be easily perceived by humans. RAR and ZIP are lossless compression formats. They work because most real world data has a lot of repetition in it, and the same information can be represented in a more compact format. For example, if I have a file with the contents \"aaaaaaaaaaaaabbbbbbb\", I could represent the same data as \"13a7b\", meaning that there are thirteen a's followed by 7 b's. Real compression algorithms are more complex and general purpose, but that's the basic idea."], "text_urls": [[]], "score": [4]}}, {"q_id": "5x82ev", "category": "Repost", "title": "How do TV shows make money, how do ratings work and do stations receive payment for them?", "title_urls": {"url": []}, "selftext": "hey guys, I'm watching Game of Thrones and they're known to spend a lot of money per episode, my question is, how exactly does a TV show make its money, how do ratings work/are measured, and are stations paid for how many people view the show? I've always wondered about all this. let me know! :) thanks", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["deg0vr7", "deg0tf6", "degtkjk", "degkbzj"], "text": ["Since Game of Thrones is on a paid network with no commercials, it works a bit different. HBO gets paid via subscribers, shows like Game of Thrones help pull in people who might not otherwise have subscribed. Add in DVD sales, and you've got pretty much it's whole pool of available money. For most TV it works a bit different through. Ratings: Ratings indicate how many people are watching a show. They're typically measured by the Nielsen group, which hands randomly selected family a special box that monitors what they watch. If 1 in 10,000 families have a Nielsen box, then each Nielsen box represents 10,000 views. It's honestly a terrible system, because certain types of are more prone to be selected/be willing to be a Nielsen family. It also doesn't take into account things like DVR, streaming, etc. Based on a shows ratings, a sponsor can estimate how many people will see a commercial if they buy air time during the show. A show like \"The Big Bang Theory\" that is routinely the highest rated sitcom on TV, can offer a huge audience, which makes its time more valuable. A 3rd string show on a smaller network gets less viewer, and thus demands less money. Ultimately the networks sell ad time to sponsors, at a rate based on ratings for the show. The network \"buys the show\" at a fixed rater per season, by paying the production company that makes the show \"$300,000 per episode\" or whatever, again based on ratings and thus earnings potential for the show.", "For cable TV, they make money through advertising. For channels like HBO, ShoTime and Stars, they make money through customer subscription. As far as ratings go, that's how TV networks know how much to charge for the advertising time. Take the Super Bowl for example. It is notoriously known for having ridiculously high ad prices because they know a shit ton of people are going to be watching. TV networks don't receive money for having high ratings, per se. There is an independent company (Nielsen) that conducts the ratings and then the Account Executives of the networks use those numbers to sell ads. I worked in radio advertising for a bit and they operate in much the same way as television.", "Most of these answers explain how TV networks make money airing shows, but shows are also profitable in and of themselves for the studios that produce them. Here's how it usually works: The Studio develops an idea for Awesome Show and sells it to a network. In this case we'll say the network is ABC. ABC doesn't actually buy the show outright though, they essentially rent it for a limited amount of time. This is called licensing. If the show costs The Studio $100 per episode to make, ABC might license it for $30 per episode, for the right to air it first and for the next 5 years. The Studio is now getting $30 back for every $100 it spends. Not enough to make money, so it goes to other networks in other countries and tries to sell the show to them. Maybe a network in Germany buys it for $10 an episode, a UK network buys it for $15, and a French one buys it for $5. That's another $30 per episode. Combined with the $30 from the US, The Studio now gets $60 back for every $100 it spends. Still not great. To cover that deficit The Studio will shoot the show in a location that gives them a tax credit for bringing shooting the production there (many states and other countries have give shows tax credits because the shows create jobs and spend $ wherever they go). So The Studio shoots Awesome Show in Canada where they can get a 30% tax credit (essentially a cash rebate), which is another $30 they can add to the pot. So now they are making $90 back for every $100 they spend. Now surprisingly, this may be all the studio is able to get at first. So they end up making the show at a loss and covering the difference themselves. This is called \"deficit financing\" and it's how most shows are made. If the show runs only one season (or just a few episodes) and is canceled, the studio is just out all that money. But if the show runs a long time (let's say 7 seasons) the economics really start to favor the studio. That's because they will continue to try and sell the show around the world, and the more successful a show is and the longer it runs, the more other people want it. So in season 3 they are suddenly able to sell the show in Belgium, Denmark, Croatia, Italy, Costa Rico and Portugal, for a total of $25. Now they are making $115 for every $100 they spend. AND, that money comes in for all three of the original seasons, retroactively covering their deficit and putting them in profit for every episode the've made. And after ABC's 5 year window expires, the money pot grows even bigger because now The Studio can sell Awesome Show in the U.S. to other markets again. When you see a show that originally aired on NBC run in repeats on TNT, that's the studio selling it again and making serious money. They'll also sell it to other services like Netflix or Amazon, sell it directly to consumers via iTunes, and if it's popular enough, put it out on DVD. All that is more retroactive income. AND, The Studio can continue to Awesome Show like this FOREVER. After TNT's second window expires in another 5 years, they'll sell the show to another market, then another and another. And now when they do the sale, it's for the full run of the show. So it's not just $5 an episode for one season, it's $5 an episode for 7 seasons. All pure profit at this point. And as new markets are created (Hulu, Netflix, iTunes) they'll sell it there too. You know how you see shows like the original Star Trek still appearing on places like Netflix or your local TV network? That's a 50-year-old series STILL generating money for its owner. And once the original cost is covered, that's pure profit for almost no work. This snowball effect can make shows insanely profitable. A successful show that runs for many season and sells well can generate BILLIONS of dollars over time. Seinfeld is estimated to have generated $3.1 billion in profit for example. And it's still selling today. I know of one show that was almost canceled every season and barely made it to five seasons (two of them shortened) and still made $100 million in profit. That's why many companies that own TV networks also own their own studios. They can sell a show to their own network (or surprisingly to other networks), and make money both on the licensing side (through ad revenue) and on the selling side. It's a money machine. (Note: This works differently for pay services like HBO and Netflix, which often pay huge sums to own their shows outright...I'm mostly talking about broadcast TV and basic cable shows).", "Neilsen ratings are going the way of the dodo bird. If your cable box is connected to the internet, most are. They are collecting information about everything you watch."], "text_urls": [[], [], [], []], "score": [287, 12, 10, 7]}}, {"q_id": "5xcisg", "category": "Repost", "title": "why do grades in school skip \"E\" and go straight to \"F\" as the lowest grade?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["deh0n20", "deh0h93"], "text": ["The oldest grades were given at Yale, optimum, magis, maxime (best, worse, worst). William Farish invented *letter* grades about 200 years ago. He borrowed the system used by shoe factories in determining if shoes were good enough for sale. Shoes were graded as \"Excellent, Satisfactory, Needs Improvement, and Unacceptable\" Excellent and Satisfactory shoes were allowed to go to market (at different prices), Needs Improvement shoes were sent back to be repaired, and Unacceptable shoes were thrown out. These became abbreviated E-S-N(I)-U. The advantage of this system is it allows a teacher to spend less time in the classroom and to have a classroom with more students. With the rapid expansion of education in the 19th century, schools in English-speaking countries adopted the faster, streamlined grading system instead of sitting with each student until he understands the concept. These grades, shortened to E-S-N-U were the most popular system used in grade schools until the mid-20th century. I went to a private school that still used this system in the 1980s. Harvard adopted *alphabetical* letter grades in the 1880s, but, reticent to equate men to shoes, it gave five ranks A-B-C-D-E. In 1897 Harvard switched to A-F grades with no E, to avoid confusion with other schools students had attended where E was the top mark. By the 1930s, the A-E system was entirely replaced with A-F at US colleges using grading systems. In the mid-20th century the notion of a grade of \"unacceptable\" seemed harsh to give little boys and girls. So elementary schools gradually switched to letters which didn't contain value judgments. Students however in colleges had already noted that the F grade could stand for Failure, and that turn was generally adopted as being synonymous with the grade F.", "The earliest usage of the letter grade system as we know it dates to the late 19th century, most notably at Mount Holyoke College, and it was in fact rated from A-E, and eventually A-F (inclusive of E), before E was eventually faded out as a rule. [Here's a nice article about it]( URL_0 ). D was never initially intended to mean \"Deficient\" as some here are claiming, but that usage may have been colloquially adopted over the years."], "text_urls": [[], ["http://www.businessinsider.com/why-there-is-no-e-grade-2014-9"]], "score": [45, 13]}}, {"q_id": "5xesz4", "category": "Repost", "title": "Why do dead batteries in remote controls work again after you whack the remote one good time?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dehjph5"], "text": ["Because they weren't dead. They may have been weak, but they were making poor contact with the remote. They may have started leaking and corroded the contacts."], "text_urls": [[]], "score": [8]}}, {"q_id": "5xfnjw", "category": "Repost", "title": "What is the significance of having headphones in the correct ears when listening to music?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dehpr9x"], "text": ["There isn't one from a music perspective, (some songs have differences in the left-right channel, but it doesn't really matter if it is reversed). The problem is with the shape of the headphones themselves. The right headphone is shaped for the right ear, so if you put it in the left ear then it will be backwards and won't be as good of a shape."], "text_urls": [[]], "score": [5]}}, {"q_id": "5xgh6d", "category": "Repost", "title": "How/Where does the electricity used in our nervous systems to send signals come from?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dehvlj6"], "text": ["This has been asked before. You should search. It is not electricity as we know it. The electricity we know flows along wires. The electrons flow freely. The nerve impulse is a rapid set of biochemical reactions along the surface of a neuron. The speed is far slower than the speed of electricity along a wire. Cations and Anions move across the cell membrane inducing the movement to continue down the neuron. There is a synapse where the axons of one neuron meet the dendrite of another. Another set of chemical reactions happen there inducing another nerve impulse to travel."], "text_urls": [[]], "score": [6]}}, {"q_id": "5xgt9z", "category": "Repost", "title": "Why do we get dizzy from simply spinning around on the spot?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dehxy23"], "text": ["Inside your ear you have a little pocket of fluid and a bunch of tiny hairs that are feeling how that fluid is moving. The fluid wants to go down because of gravity. This helps you know where down is. It also moves around when you move around. So you can tell that the car you're in is accelerating, you've turned your head suddenly or even falling. When you spin around and around it's like swirling water in a glass. You get a small whirlpool effect. So the fluid in your ear is still moving and splashing around. Which means the tiny hairs are getting weird messages. Your brain is trying to understand why you're moving all over the place and why down keeps changing. So you keep trying to adjust your balance to counter what movement your ears feel and wherever down seems to be but it's never in the same spot for very long and never where down actually is. So you usually stumble and fall. One solution to the problem is to quickly spin once in the other direction. This cancels out the momentum the fluid has and settles everything down. No more dizzy."], "text_urls": [[]], "score": [4]}}, {"q_id": "5xh5od", "category": "Repost", "title": "How is it that I am allowed to take oestrogen if I feel like a woman trapped inside a man's body, but not testosterone if I feel like a strong, attractive man trapped inside a weak man's body?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dei0dno"], "text": ["Um, well...you can. You just can't actively participate in competition sports that outlaw steroid use. So, go for it. I am sure you can find a doctor to prescribe it."], "text_urls": [[]], "score": [3]}}, {"q_id": "5xidge", "category": "Repost", "title": "How do chip-embedded credit cards offer more security when in fact they seem more inconvenient?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["deia4v2", "deidceg"], "text": ["The data on a magnetic strip is just stored there passively. If you copy the magnetic data, there's no way for the data to \"know\" that it has been copied and put on another plastic card. On a card with a chip, the chip contains electronic circuitry that performs cryptographic calculations when it is read, which means every time the card is used, the card reader gets an unique value calculated by that particular chip. A chip on a different is not able to calculate the exact same values because of the cryptographic functions found in it, and therefore you can't copy the contents to a different card. I have no idea why you'd still need to sign it. That's only a backup solution here. If the chip reader can't get a network connection to verify the code, you have to sign it as a regular non-chip card. Perhaps most of the stores you go to just haven't bothered investing in the devices and services required to give you a safe transaction?", "The problem is mostly with the way the US has adopted chip technology, which is not nearly as secure as the way the technology has been adopted in other countries. In other countries that have implemented chip technology for credit cards, chip + PIN is usually the default or mandatory standard (meaning that you are required to input your PIN every time you insert your chip card into a payment terminal). However, in the US, most cards are still using the signature method so that if/when a person's credit card gets compromised, a criminal does not need to know a PIN to complete in-store transactions. Another difference is that in other countries that have implemented chip technology, just about every single payment terminal in the country has already been upgraded to support chip cards. Additionally, these chip terminals will not allow you to swipe cards (using the magnetic stripe) if they were issued by your bank as chip cards. This basically means that if someone does manage to duplicate the magnetic stripe on your card (which is relatively easy/trivial to do), the duplicate card is essentially rendered useless because nowhere will accept it (all the stores, restaurants, etc. will require the person to insert the chip which is extremely difficult to duplicate). However, in the US, many payment terminals\u2014especially at restaurants and fast-food outlets\u2014are still not equipped to process chip transactions and still use the older magnetic stripe method, leaving open a massive security hole. Another difference is that in other countries like Canada that have implemented chip technology, the customer (even at restaurants) maintains possession of their credit card at all times. That is to say, employees never ask a customer to hand over their credit card and don't take it away or out of view from the customer. Ideally the employee is never supposed to touch the card and the customer is supposed to complete the transaction using the payment terminal completely on their own. However, in the US, there are many situations\u2014especially at restaurants and fast-food outlets\u2014where employees do ask you to hand over your card and will take your card away (out of view). This provides an additional opportunity for employees to skim/duplicate your card or write down your card details which increases the chances your card may be compromised online or duplicated and used fraudulently at locations that still are using magnetic stripe technology. So chip technology provides many security advantages when it is implemented properly, but unfortunately the way it has been currently implemented in the US provides very limited protections and still leaves a lot of opportunities open for credit card fraud."], "text_urls": [[], []], "score": [17, 7]}}, {"q_id": "5xj63m", "category": "Repost", "title": "Our bodies have adapted to make sugary things taste good since they provide energy. Why hasn't the same thing developed with healthy items like vegetables?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["deigb0g", "deiirc6", "deig8xs", "deivx8r"], "text": ["Because vegetables don't provide as much energy as sugars. They are only considered healthy in a modern context of an abundance of food. If you go back several thousand years (an eyeblink in evolutionary terms) finding enough food was a real problem that occupied most of your time. High energy foods like sugary fruits and fatty meats were *way* better than vegetables.", "In addition to the others, many of the nutrients in veggies are important to overall healthy lifestyle but calories keep you going. In a survival sense it critical to keep calories up to keep you moving. Vitamins and minerals are a luxury by comparison. Edit: An anecdote: I recall a story of a man in a life boat lost in the ocean. He distilled sea water and caught fish to survive. I remember he said for the first days and weeks he was eating the meat of fish but after a while he was suddenly craving the skin and organs of the fish. He had satisfied his caloric needs but as his body started needing those other nutrients his cravings shifted to account for it.", "Because healthy items such as vegetables provide little energy and what your body wants is not to stay healthy but to stay alive. For that, the first thing it must do is not starve. Energy not used is stored as fat for later. This will keep you alive if you don't find more food this week.", "In modern society we have access to a shit ton of food. By age 20 you have probably eaten more food than most \"cave men\" ate in their entire lives possibly earlier than that. Eating a full 3 square meals a day is great and when you can get those by simply heading to the store you can balance a proper healthy diet. But back in caveman days you ate what ever the fuck you could get you hands on. Yes you could eat apples on an apple tree as long as it was summer and other competitors for that food source had not eaten it already. But an apple only provides so many calories and is only available at certain times a year. Meat on the other hand is available year round and killing an animal would provide you with far more calories than eating 15 apples would. So the \"cave men\" whos bodies wanted meat instead of apples had a better chance to reproduce because they were able to eat year round and when they ate they ate better. When they woke up and got hungry they chose to go hunt instead of go to the apple tree. Over time the natural selection of these genes that made people want more meat and sugars instead of carrots (via them tasting better than the other options and having stronger cravings for the higher calorie option) survived better and had more offspring because they had denser muscles and better fat reserves (traditionally speaking this is why women like men with big arms and strong shoulders/backs because it means that they were able to actually eat because they could hunt and get the calories to make those muscles and would be able to provide for you). Skip a few thousand generations and you come along with those same genes that make a steak covered with butter or Honey buns taste far better than a salad with no dressing."], "text_urls": [[], [], [], []], "score": [33, 9, 8, 3]}}, {"q_id": "5xjdgy", "category": "Repost", "title": "How did the configuration of the computer keyboard come to be?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["deihpln"], "text": ["The QWERTY layout was designed with typewriters in mind to keep commonly used clumps of letters separated, preventing jamming of the hammers while typing."], "text_urls": [[]], "score": [3]}}, {"q_id": "5xk9n3", "category": "Repost", "title": "Are GMO foods actually harmful or are people against them for other reasons?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["deip4o7", "deirllr", "deipa4y", "dejfmv9", "deisdpy"], "text": ["When people hear \"genetically modified\" it can often times startle them, in truth, there is nothing to worry about. In fact, genetically modified fruits often stay ripe longer and can contain more nutrients than normal. I believe the most common reason is the fact that not everyone fully understands the effects of gmo fruits, which may alarm them.", "> for other reasons Genetic engineering is not permitted in organic agriculture, thus the organic industry demonizes it in order the protect/increase their market share.", "There really hasn't been evidence that they are harmful...unless there is some massive food conspiracy. I think it just makes people uncomfortable and it's hard to trust because it is some serious tinkering with nature. We really are kinda playing god and redesigning organisms for our convenience. It's weird, but I don't care about it really...as long as the food is cheap I'll still buy it. I can certainly understand the apprehension but food is still food.", "[Have you considered reading the last 200+ times this was posted in this sub?]( URL_0 )", "There 2 major issues that are attached to this: 1) GMO's (some, not all, but blame Monsanto for most) are engineered to be sterile so farmers cannot save seed. This is bad because it could easily lead to mass famine and other issues. In short, it is a business attempt to control food supplies. 2) Some GMO's use 'natural' pesticides like [**BT**]( URL_0 ) that hasn't been tested in the way other pesticides are tested. It is considered safe, but nothing is totally safe and there are always unforeseen circumstances."], "text_urls": [[], [], [], ["https://www.reddit.com/r/explainlikeimfive/search?q=Monsanto+OR+GMO+OR+%22genetically+modified%22&amp;sort=new&amp;restrict_sr=on&amp;t=all"], ["https://en.wikipedia.org/wiki/Bt_cotton"]], "score": [20, 7, 5, 3, 3]}}, {"q_id": "5xn3o9", "category": "Repost", "title": "What is the purpose of the International Space Station?", "title_urls": {"url": []}, "selftext": "And the space program in general for that matter. Like most people reading this right now, I'm a science oriented thinker driven by curiosity and turned on by knowledge. I hear political arguments on the opposing view that (US tax) money is better spent elsewhere. What are the main goals and expectations of the space program as it stands now, funded by 'the people'?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dejbzjw", "deje4hg", "dejceet", "dejik26", "dek5z1b"], "text": ["The space station is currently used for conducting experiments in micro gravity. But it can also be used as a checkpoint for longer missions that require heavy payloads. For example: if we want to send a ship to the moon we can send the ship without fuel to the ISS (International Space Station) and then send the fuel tank to refuel the spaceship. Tell me if you require further explanation", "The ISS is essentially a research station in Earth orbit. The astronauts there perform a variety of experiments that can't be performed on Earth (usually because they examine the effects of microgravity). These experiments cover a wide variety of topics, including, biology, genetics, physics, astronomy, meteorology, and many other fields. A focus of these experiments is to examine how extended stays in space effect humans. If humans ever want to leave Earth (to go to Mars or beyond), we'll need to know how the human body will respond to a long term stay in space. As for the purpose of the space program: In general, its purpose is to explore the origin, evolution, and future of the Earth, the Solar System, and the universe. If you're talking about studying the Earth, this has important implications: Think weather patterns, storms, atmospheric composition, stuff like that. Much of these measurements are taken with space based observation satellites, and it's hard to argue against their results. It's nice to know about a hurricane a couple weeks before it hits your house. We also observe our solar system through the use of telescopes and space probes. These can help us answer questions about our planetary neighbors and their evolution. These can answer questions that are important to our survival as a species. Things like: Why did Mars become such a frozen wasteland? Can that happen to Earth? How did Venus's runaway greenhouse effect turn the planet into the literal definition of Hell? Could that happen to Earth? Are there ways to predict solar flares that could knock out power grids here on Earth? What about asteroids? How many are out there that could hit Earth? In addition, they answer other things about our place in the universe. For example, we now believe (thanks to our space exploration program), that Mars (and maybe Venus, too) were warm, temperate worlds with flowing water, just like Earth. Did they have life? If they didn't, why didn't they? Is life on Earth special, or could it have developed elsewhere? Could Humans eventually live on Mars? These are all questions that our space program strives to answer. Lastly, we have many telescopes in space that observe the rest of the universe (the most famous of these is the Hubble Space Telescope). These telescopes are in space mainly to avoid looking through the Earth's atmosphere, as the atmosphere distorts images (think twinkling stars). These telescopes again help answer fundamental questions about the universe and our place in it. For example, just 30 years ago, we didn't even know if other solar systems had planets. Know we know that almost every star has at least one planet, and about 20% of those have planets similar to Earth in size and orbit (maybe habitable). We also are able to peer into the early universe and examine the way it has developed over its lifetime. This can pave the way to new discoveries about the laws of nature. All in all, I think most of those are pretty noble causes. And the United States has the world's biggest space program, but we only spend about .5% of our budget a year on it (~$18 Billion). So yeah, maybe we can find better short term places to spend them money, but I see it more as a very small investment into our future as a species with huge potential payoffs.", "This article brings up many good points. URL_0 To summarize: 1. Tech developed for space exploration has turned into important modern tech (MRIs , smoke detectors, etc). 2. Space programs educate the public 3. Creates lots of high skill jobs 4. Gets us closer to becoming a multi-planetary species. It's extinction insurance for when the next mass extinction event happens on earth. 5. We learn more about the origin of the solar system and our universe. The value of this information in intangible but the more we understand our environment the more we can control it.", "I have done a LOT of research into the station, but I'm in no way an engineer on the project. The station is used to study how people/animals/bacteria/diseases/etc. react to microgravity. The station is large enough to support a LOT of experiments at once, (I'd say thousands but I'm unsure on that number) some even in the vacuum of space (That station has multiple airlocks that can be used to move experiments out into the vacuum). They also search for cures to diseases that may have to be made only in space, such as possible cures for cancer. Also, multiple Earth-observing experiments are onboard the station, such as ones to monitor the ozone layer, rainfall totals, lightning, etc. The ISS may also be used to test out new technologies for space exploration, such as new foods, exercise equipment, spacesuit designs, etc. Finally, many commercial companies can test out large-scale pieces of equipment onboard the station, like Bigelow's inflatable test module, and Boeing's future small experiment airlock. One side effect of having the station that you may know about is the amount of amazing pictures taken from the station.", "I keep this link in my back pocket every time someone asks why money should be spent on the space program instead of \"things here on earth like poverty, etc.\" Dr. Stuhlinger's letter speaks for itself. URL_0"], "text_urls": [[], [], ["https://www.google.com/amp/www.universetoday.com/37079/benefits-of-space-exploration/amp/"], [], ["http://www.lettersofnote.com/2012/08/why-explore-space.html"]], "score": [76, 65, 37, 4, 3]}}, {"q_id": "5xnpzk", "category": "Repost", "title": "Why does paper not burn when put in the microwave?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dejgqng", "dejgjkk"], "text": ["Microwaves work by exciting water molecules, and the water conducts that heat into the food. Paper has virtually zero water in it, so it doesn't heat up.", "A microwave only produces heat in objects that contain water molecules. So items that are completely dry like paper towels won't heat up."], "text_urls": [[], []], "score": [4, 3]}}, {"q_id": "5xrzl5", "category": "Repost", "title": "How does a fighter jet's defense system know that a missile has locked onto the jet?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dekfa87"], "text": ["When missiles lock onto a craft the tracking measures they use ie radar focuses down on that craft and pings much faster to get more accurate and frequent readings . If the aircraft has sensors they can detect this focusing of pings. However not all missiles use aggresive tracking measures (sending signals out) some use passive measures such as heat seaking missiles."], "text_urls": [[]], "score": [7]}}, {"q_id": "5xsa0q", "category": "Repost", "title": "Time dilation", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["deki3zz"], "text": ["What time dilation is not: --- In order to explain time dilation, let me fist explain what it is **not**. A popular, but entirely wrong notion of time dilation states, that time passes slower the faster you move. A quick examination of this claim, however, reveals that it cannot be true. There is no absolute velocity, so velocity only makes sense with respect to a frame of reference. Thus, if this version of time dilation were true, time on your spaceship would magically speed up and slow down depending on the frame of reference you measure your spaceship's velocity against. Thus, the statement that the rate at which time passes depends on your velocity (relative to an arbitrary frame of reference) cannot be true. Now, let's get started with actual time dilation: Why does time dilation happen? --- To understand how time dilation can happen, let's consider the following thought experiment: A clock is any object that does an action periodically. As such, a light beam bouncing off two mirrors can be considered a clock, with each period of the photon bouncing up and down again being one tick. Let's now consider a train with such a clock in one of the compartments, as seen [here]( URL_0 ). Imagine a person in a train with a flashlight. They shine the beam of the flashlight across the carriage and time how long it takes to return to them. Very simply it is just the distance the light travels (twice the width of the carriage (d)) divided by the speed of light (c). Someone on the embankment by the train will also agree with the measurement of the time that the light beam takes to get back to the person with the torch after reflecting from the mirror. They will both say that the time (t) is 2d/c. Now consider what happens as the train moves at a constant speed along the track. The person in the train still considers that the light has gone from the torch, straight across the carriage and returned to them. It has still traveled a distance of 2d and if the speed of light is c the time (t) it has taken is 2d/c. However to the person on the embankment this is not the case. For them, the train has been moving during a tick of the clock, and the photon has to travel a longer distance accordingly. Now in classical physics, pre relativity, we would now say that since the light beam has moved further in the same time it must be moving faster, in other words we have to \"add\" the speed of the train to the speed of the light. But the theory of relativity does not allow us to do this. It says that the speed of light is constant. Thus, the photon will take longer to reach its destination from the point of view of the observer on the embankment. Hence we know that it takes the photon longer to complete this journey from the point of view of the observer on the embankment than it does from the point of view of an observer resting in the train. And we know that the time it takes the photon to complete its journey up and down again corresponds to one tick of a clock. Thus, it follows logically that the observer on the embankment sees clocks on the moving train as ticking slower than someone resting in the train. Which is exactly what special relativity is all about. Due to the equivalence principle, however, it is entirely valid to state that the train is at rest and the embankment is moving at a velocity of -v relative to the train. This leads us to the conclusion, that the clocks on the embankment are also slowed down from the perspective of the person on the train. This means, each observer sees the clocks of the other observer as being slowed down. This might seem paradoxical at first, but can be solved withing the confines of special relativity. The thought experiment addressing this issue is the so called Twin paradox: --- One of the central claims in special relativity is, that all inertial frames of reference are equally valid to describe a phenomenon. That is, the laws of physics are the same in all frames of reference that are not being accelerated. This is called the equivalence principle. Consider an inertial frame of reference I and another inertial frame of reference I' that moves at a constant velocity v relative to I. Time dilation states, that an observer O resting in I will measure clocks resting in I' as ticking slower than their own clocks. According to the equivalence principle, the same statement has to be true for an observer O' resting in I' as well, since they are both in inertial frames of reference. Thus, the observer O' resting in I' sees clocks resting in I as ticking slower than their own. **Time dilation is a symmetrical effect. Both observers see clocks in the other observer's frame of reference as ticking slower.** \"But wait\", you might interject at this point, \"what about the [twin paradox]( URL_1 ). The twin making a trip to space ages less than the twin remaining on earth. Doesn't that contradict what you are saying?\" While that seems true on the first glance, this is actually not a contradiction. In order for the twin paradox to work, the twin traveling in the space ship has to return to earth. In order to do that, he has to change direction at some point. This change in direction implies acceleration, and acceleration breaks the symmetry of the problem. Remember, that we stated that all *inertial* (un-acclerated) frames of reference are equal. By accelerating, the space traveling twin breaks the symmetry of the equivalence principle, thus leading to the observable difference in passed time."], "text_urls": [["http://www.schoolphysics.co.uk/age16-19/Relativity/text/Time_dilation/images/1.png", "https://en.wikipedia.org/wiki/Twin_paradox"]], "score": [6]}}, {"q_id": "5xvb7f", "category": "Repost", "title": "Why is discovering the Higgs-Boson particle so significant?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["del4y6b", "del4lsg", "delqj3q"], "text": ["The Higgs boson was the last major prediction of the Standard Model of Particle Physics, but for many years it's discovery eluded physicists. The Higgs mechanism tells us how elementary particles get their mass. You can imagine the Higgs field being like treacle. Particles which couple to the Higgs field will slow down from the speed of light in the field. If they do so, they have mass, like the electron. If not, they are massless, like the photon. There Higgs boson is an excitation of this field, like a vibrating spring in a mattress, and finding one confirms that the field exists and the mechanism is correct. But the Higgs boson was predicted to have a very high mass (although the exact value could not be predicted), and therefore would be very short lived because it could quickly decay to lighter particles. This means you don't see many of them hanging around, so you need to put a lot of energy into one place to make one. This is one of the reasons why scientists built the LHC, as it allows us to accelerate particles to extremely high energy, smash them together, and see what the energy of that collision makes by analysing the products. They managed to do this in 2012. So, finding the Higgs boson confirms the last major piece of the Standard Model. But it also has more potential than that. While the Standard Model does a great job of explaining everything it tries to, it leaves a lot out, namely gravity. If we can find any irregularities in the properties of the Higgs from what the Standard Model predicts, we might be able to find a lead to the new physics we desperately need to connect quantum field theory with gravity. More analysis of the Higgs will be done in the coming months and years to see if we can find any such leads.", "It verified parts of our current mathematical model of the fundamental functions of our universe, which predicted the existence of the particle, though that partical had never been observed. That means our current model of the universe is close to correct in this area, and is therefore useful for predicting how certain things behave.", "Ok so quick tl;dr version of quantum field theory. 1: A field is a function defined over some region space and time. If that sounds scary it's not. You're used to some of these, think gravitational fields and magnetic fields. 2: In the case of quantum fields, they're what give rise to the fundamental particles. Individual particles are excitations in their related quantum field. Basically this means there is for example one electron field and every election can be described as an excited state of that field. That's a littreal scarier, but the nutshell is that if you find a fundamental particle, it means it's field is also a thing. 3: The interactions between those particles can be described by the interactions between the corresponding quantum fields. The higgs field in particular is of major interest, because interactions with it are why some particles have mass, which is why everything isn't traveling at light speed and why we're here talking about this. You'll note the lack of qualifiers in that sentence, a couple years ago the words \"we think\" would have been included there. 4: Those fields are a PITA to study directly. You can use QFT to make empirical predictions and etc, but you can't realy point at something and go \"yup that's the higgs field\" 5: fortunately if the field exists it has a corresponding particle, and particles are things you can point at. So if you find the higgs boson (which is the particle associated with the higgs field), and its properties match the theoretically predicted ones by extensions you've gone a long way to confirming the existence of and the properties of the higgs field. Which is kind of a big deal, if you do that you get to move from \"we'll this is probably right\" to \"yup this is definitely how things work\" In the case of the higgs boson it was a big deal because it had been predicted to be a thing back in the 60s and half a century of waiting for confirmation is a long time to build hype, especially when it proved to be much much harder to create and detect than initially expected. The LHC was built in large part to finally find the damn thing."], "text_urls": [[], [], []], "score": [52, 9, 5]}}, {"q_id": "5xve3i", "category": "Repost", "title": "Why is our brain programmed to like sugar, salt and fat if it's bad for our health?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["del57eb", "del9ntq", "del7v5t", "del64db", "deld7en", "del4uie", "deldenf", "del4ql6", "delglek", "delic8t", "delexs6", "del56cj", "delc8yf", "delp296", "del9rs5", "delbngj", "delg0qn", "delc66t", "delbhcm", "deln5ls", "delih58", "del7zrb", "delex2o", "delhztw", "delm63v", "dels1gm", "delpkm2", "delc4pp", "delfgl3", "del9wd0", "delnflt", "delbg6p", "delkpq2", "dem3lkd", "delnmsk", "del9jhn", "dem5hh9"], "text": ["As humans, we're only separated by about ~20,000 years from our hunter/gatherer ancestors. That period of time is extremely short in terms of evolution so although we live completely different lifestyles, our bodies have not changed much. We crave sugar, fat, and salt because they were \"healthy\" back in those days just because of how rare those things were to our hunter/gatherer ancestors. Being able to eat the calorie dense sugar and fats means that we would be able to survive more days without food, improving our overall \"health.\" We needed salt to replenish all the salts lost through sweat because humans are built for endurance running (early human hunters would jog along until the prey runs out of energy). The humans who didn't crave sugars, fats, and salt would not build up enough energy and wouldn't survive as well as those who did crave them. Nowadays, the food industry takes advantage of our primitive brain cravings to sell us more food. Normally, a person only eats a constant amount of food. If that was the case, for the food industry, the profits will never increase. They have to make people eat more food to generate profits. Thus, there is a strong incentive to put more sugars, fats, and salt in our foods so we eat more of it, regardless if it was healthy for us.", "It isn't bad for our health. They are essential for life. When we lived in the wild those were the things that retained water best for us (salt), and had the highest calories (sugar and fat). Our brains don't know they live in a time where food=fridge in a sense, so it is still in 10,000 BC where when you find sugary and fatty food you pig out on it to gain fat to hold over until you can get your next bit of fat. Think of a gas engine. Give it gas, and it functions. Give it 40L of gas and it will function longer. Give it 100L of gas and it will function even longer than with 40L. Sure, it'll weight more having a bigger tank attached to it, but It'll just keep humming along for that much longer because it has that much more gas. The gas engine will only last as long as it has gas, and because it doesn't have knowledge of when it will consume some again it will allow you to fill it as much as possible. Exactly like the body. That part of the brain only functions in the now you could say, and that is why it goes \"FAT/SUGAR/SALT!!!! GIMME GIMME!!!!!!!!\" because it knows that eating 1lb of those foods will make it survive far more than foods with very little of it. So due to being \"cut off\" from the other parts of the brain that could think \"we can just eat more in 3 hours....fat ass\" it will just forever crave it as long as it knows it's in front of you. **Edit/sidenote:** It's trans fats that are bad for us, processed sugars(in relations to it often being found in empty calories), and TOO MUCH of those. All those metals we need in our body do wonders for us, but my god can they do damage to us if we consume too much of them. Much like anything we consume: moderation. It's all good in moderation, and all bad without. Look at fibre. It can constipate you, but can also give you diarrhea. **Edit2:** Should've mentioned a bit more detail about sugar. Its the only energy source for the brain. While people explained to me we, as mammals, can make our own. With that being said, it is still easier to just consume some instead of making the body do it all itself. **Edit2b:** I have been informed by many of you that recently science has discovered that the brain can survive on ketones made by the liver with fats. **Edit3:** Thanks for the gold and the upvotes everyone! **Edit 4:** Many people pointed out I screwed up on my explanation when I said sugar=high calories. What I should've/wanted to say was that sugary foods were highly beneficial to our survival due to often being rich in nutrients (apples, berries, etc), and being found in abundance (apple tree with 800lbs of apples). I didn't mean to make it sound like gram to gram sugar (carbs) has more calories.", "It's not bad for our health, in the amounts we \"naturally\" get it. We're programmed to seek out the biggest bang for the buck, nutritionally speaking. For most of our history, resources were scarce, so we needed to be encouraged to seek out the stuff that would do us the most good. That's why we like those flavors. The problem is in modern time, that scarcity doesn't exist anymore, but we're still programmed to act like it does. If you eat \"bad\" stuff in moderation, you'll be fine. It's only when you regularly gorge (eat more than you burn) that it really becomes a problem.", "Because sugar, salt, and fat are only bad for you when consumed in excess amounts. In fact, salt and fat are quite necessary for a healthy diet. For the vast majority of human history those things were not available for consumption in excess amounts, except for by the most wealthy nobility.", "First of all, nutritional fat isn't really that bad for us. That's a myth that was pushed for decades in the US, because the sugar companies wanted to cover up the real cause of obesity. Second, humans today are in a much different situation than our ancestors. They had to hunt and forage for everything they ate, so if there was a way to eat something that would provide quick energy and some fat storage, it was great. Today, we have no problem getting enough to eat. The problem is getting ourselves to stop eating when we're already full.", "Because for most of humanity's existence (when the genes were selected that determine your tastes), the risk of starvation was much higher than the risk of obesity related diseases. Sugar and fat were great sources of calories to avoid starvation.", "Salt is only bad for you if your organs already don't function well and/or are unable to drink enough potable water. Fats aren't bad for you, with the exception of artificial trans fats, which are only possible to make with modern industrial methods. With the exception of trans fat studies, there is a dearth of studies on the health effects of dietary fat that are focused on healthy populations, with control groups, that account for lifestyles and food quality in general. Naturally occurring sugars tend to be fine because they're packed with water and fiber and it's neigh impossible to match a Western diet without processed foods. As with trans fats, processing makes them bad for you.", "Mostly because evolution is very slow, and it's only recently that we've had access to those things in large enough quantities to present a danger to our health before we were able to pass on our genes. Sugar, salt, and fat are important parts of the human diet. And that's doubly-so when we had to chase an animal for a few miles and beat it to death with a rock and a stick. As far as evolution is concerned, we're still right about at that level--so it makes sense that the body is designed to crave those things and get them when it has access to them.", "Your question is based on the dubious assumption that fat is bad for you. That aside - If you get a ruler and put your finger on 29.9cm the bit that is left is about where 'we' are in terms of human evolution. For the rest of this time we were out hunting animals to live. Humans survived because we were great over long distance. As long as we could follow the prey - the prey was fucked. So we had a high fat/protein diet. Every now and then we would find some berries etc and it was like motherfucking xmas. This would give us a mad sugar rush, so we are programmed to crave fat and sugar. (Our brain knows these kept us alive.) Problem is that these days instead of our hunter gatherer brethren who had a 99/1 ratio of fat/sugar we now have something more like a 70/30 the other way. Even if we were still running all day to catch a fucking elk this still wouldn't be a great diet. The brain can't cope with this much sugar (anyone who tells you to lower your cholesterol doesn't realise what makes up 1/4 of the brain yet) and I'll assume everyone knows about blood sugar by now. So...tldr: Our brains crave what they need. It's our shitty interpretation of this that is making us all sick, fat and smelly :) Edit - So many good answers here that probably explained it better, but I said fuck a few times so I'm just gonna leave it.", "For 99.9999999999% of our evolutionary history, the biggest threat from food was not getting enough. Starvation. Foods that are high in calories and easy to digest are excellent anti famine foods. Imagine you are stuck in the desert and come across a fast food value menu. That'll provide 2000 calories for less than 5 minutes of chewing and eating. That is enough energy to walk for hours. Basically, its only today when we have an unlimited supply of anti-famine foods that it causes us to develop health issues like diabetes, obesity and vascular disease.", "The only one or these that is truly bad for you when eaten on a regular basis is sugar. Humans are well adapted to eating fat and require salt to function. Sugar, however, messes with our hormones and is metabolized by the liver directly into visceral fat, ultimately leading to fatty liver disease.", "The human brain did most of its evolution prior to the 20th century. Prior to the 20th century, famine and salt-deficiency were major killers, not colesterol buildup or high blood-pressure (also infection, plague, and violence). People also had kids earlier (20 year-old Romeo crushing on 14 year-old Juliet wasn't creepy by the contemporary standards), so there was limited evolutionary pressure to extend the human lifespan beyond 50-60 years old, an age where hard-laboring farmers became more burden than help to their families. Therefore, the unhealthy excesses of sugar and fat simply wasn't possible for most people, and other deaths probably people before obesity got the chance, so getting your hands on as much salt and fat as you could was generally a net benefit in context.", "Fat is a necessary macro nutrient you need and salt is a necessary electrolyte you need. You don't need sugar but it's an easy to digest source of energy.", "Our instincts and tastes evolved long before we became civilized and technologically advanced. In our natural, pre-mega-technological state, things that are bad for us to overeat were rare and valuable to our diet - salts, sugars and fats were hard to get, and virtually impossible to get too much of. In small amounts they are all vital to our health, making us strong and powerful. This positive effect became a strong selective force that pushed us to evolve the instinctual desire to eat them. Lethargy and bad body habits were also difficult to achieve - you didn't have a choice to sit in an air-conditioned apartment and binge netflix. You had to interact with community/nature for food, materials and entertainment. Any extra rest you could 'steal' was a bonus, so we evolved to desire lethargy even though we couldn't maintain it. It used to be impossible. Fast forward to 2017, we mass-produce everything and live cushy lifestyles. The impossible combination of sloth and overeating is now possible. Our instincts are outdated, but they don't kill us before child-bearing age. Thus we are unable to evolve a counter-balancing set of instincts, stuck in the loop of the desire to eat chocolate cake until diabetes.", "Evolution doesn't really care about our concept of health. It just cares that we reproduce before we kick off. Whatever food gets us there, is evolutionally \"healthy\".", "Because those are hard to find in the wild and we do need them in small doses so our \"caveman brain\" is programmed to always be on the look out. Only problem is now you can get all three for $8 at a drive though.", "As I explain to my students... \"you have an instinctive urge to eat them. Two are energy sources (sugar and fat) and the other is an electrolyte (salt). 100,000 years of humans and human like species were instinctual like all animals. We increase our probability of staying alive with them in our diet, hence you and I like eating them so much.\" Edit:wording", "Sugar and fat aren't bad for you. In a way, the reason they're unhealthy is they're *too* good for you. Sugar and fat have extremely high energy density. You get a LOT of calories per pound...so when we lived as hunter gatherers, it made sense that you wanted food that provided you with as much energy as possible, so evolution conditioned us to seek out foods that contained a lot of both. Basically a green salad might provide you with enough calories to sustain you for a couple of hours. A big slice of cake will give you enough calories to last a couple of days. The problem is that today we don't spend all day walking around a forest gathering nuts and berries, or spending a couple of days tracking an animal for its meat. We call the pizza place and get our food delivered to our door. Basically, we're eating a lot of high-energy food, but not working enough to burn off the calories...something our primitive ancestors didn't have to worry about. It's a similar situation with salt. Salt is an extremely important micronutrient. It acts as an electrolyte and, quite simply, we can't live without it... but salt only occurs in tiny amounts in most of our foods, so our bodies basically treat it like crack. When we find a source our bodies essentially go \"Holy crap! Salt! Get as much of this as possible!\" Of course, today, salt is everywhere, but our bodies have evolved to treat is as a rare resource.", "Fat isn't bad at all. Salt is quite necessary, but of course take it in moderation. Sugar is garbage. Get it from your fruit and cut the rest out as much as possible. We're programmed to like it because of its rarity back in the day, but the stuff we're consuming right now is toxic trash.", "Sugar is what's really bad for you. It acts like a drug and messes with your hormones. Nothing wrong with salt and fats. Your neurons need both to function. You don't need sugar.", "Salt and fat are not bad for your health. Unless combined with sugar. However, sugar alone IS bad for your health.", "It's much worse for your health to have no access to any sugar, salt, or fat at all, so they taste good to get us to seek them out.", "In the quantities we could get it in when we had to hunt our own food the more you could get the better", "Because they're great and necessary for our health. Sugar is rare in nature. Industry concentrates sugars and fats and makes obtaining them totally effortless. There is no obesity in the wild.", "Human evolutionary biologist here. This is a classic example of an \"evolutionary mismatch\" in which what was once an advantageous behavior (consuming as many calorie-rich foods as possible) is maladaptive in the current environment. Premature death from obesity was not a major force of selection in human evolutionary history, but starvation was. See also: My fat cat. Another example of evolutionary mismatch is moths being attracted to lights. In the evolutionary past, the only lights at night came from the stars, so moths evolved to navigate by starlight. Add artificial lights to the system and now this once-adaptive behavior is seriously maladaptive.", "Too much of anything is bad for you. This is the issue, not the sugar, salt and fat themselves. Food is essential to life. The reasons why we crave junk foods...well I'm shit at explaining but I'll try. Basically they're dense and full of energy, its easy to break down by our bodies and gives us instant gratification. Sends a lot of happy signals to the brain, but it doesn't last very long and lends you to craving more. A vicious circle. Because it's so dense, its very easy to eat too much of these maligned sugar, salt and fats. That's when the health problems come.", "Fat isn't bad for us. See paleo and keto diet ideologies. Saturated fats have been improperly demonized by science thanks to funding from the sugar industries.", "I'm going to go against the grain here and say that salt isn't bad for you, even in excess. The hypertension caused by salt is temporary and not associated with negative health outcomes. You'd have to eat a crazy amount of salt to really hurt yourself. [ URL_0 ]( URL_0 ).", "It's not. You've been programmed about that by Big Sugar, and Big Agriculture in general. Sugar is bad for the brain, and fat is a much better food source for it. If you eat a keto diet for a while, you'll feel less hungry, sharper, more energised, and won't even like the taste of the sugar-laden junk sold in stores, much less crave it.", "As every time this is asked, because they are only bad when eaten in excess. Salt is necessary for many biological processes and must be consumed for you to continue to live. Sugar and fat are highly calorie dense, so in the far past when food was scarce, sugary and fatty foods offered the best bang for the buck as far as energy expenditure per calorie gained was concerned. It's only now that food is so abundant that we can be selective enough to not eat all the food available to us.", "Because those things are not bad for your health. They are ESSENTIAL to life If you drink enough water you die from hydro-shock, do you categorize water as \"bad for your health\" too ?", "Is it just me or is \"Explain like I'm 5\" supposed to be in simple terms yet most answers for physics and science are very complex I'm new to this subreddit please correct me if I'm wrong", "Fat and salt are not bad for you. Fat gives good calorie density and salt provides electrolytes, too much of either is bad for you. Sugar is the only one which is generally bad for you, but again can be consumed sensibly with mild issues.", "Sugar is horrible, anything refined to a powder can be considered a form of sugar. It's basically toxic and is the leading cause of food triggers. The fat on your meat is the healthiest part of red meat. Salt, shit girl we all crave that mineral just take it easy.", "Actually.. On the ketogenic diet these are STILL the best fuels for our bodies and minds. I shit when I seen someone say that they weren't. Our bodies need 10,000 years to adjust genetically to any massive technological change like the agricultural boom we experienced which is how we've got shit loads of food on the shelves in stores and other madness. RIP.", "Because we evolved to take advantage of things in a state of scarcity. Sugar, before modern civilization was rare, and things that were sweet often provided a lot of nutrients needed to survive. However, with modern agriculture, we have way TOO MUCH sweet stuff today and we tend to overeat, not undereat, and we tend to make artificial stuff with things like fructose, which is far less healthy than natural sugars found in fruits. Our sense of liking sweet stuff, back in the day drew us to fruits and stuff. Now we drink tons of soda and stuff which is extremely unhealthy.", "This is actually backwards, believe it or not. Sugar, salt, and fat are bad for our health *because* our brain is programmed to like them. These are fairly rare in the wild, but they're needed for survival. We need carbohydrates (sugar) and fat in order to survive, but these things aren't so easy to find. The fruits we eat today have been bred over the last few thousand years to provide us sugar, but they don't have fat; meanwhile, our only source or protein and fat is animals, unless we turn to agriculture (tofu doesn't grow on trees, generally). Animals are difficult to obtain. So, we pretty much have to like those things so that we'll spend the effort required to get them, because we will die without them. Salt is necessary for our electrolyte balance, but it's even rarer, and it's also part of eating animals that have these electrolytes in us (there's a whole food chain thingy to get us our sodium). Well, we humans are smart, and we figured out ways to obtain sugar, salt, and fat much more easily: farming. Or however it is we get salt -- mining, drying seawater, etc. In the last several decades, we've improved on these processes *so* much that it's actually cheaper to eat foods with sugar, salt, and fat than to eat foods without them. All because our brain is programmed to like them. We invented capitalism, which means that companies will sell us what we'll buy, and we'll buy what our brains are programmed to like, so companies will pack their products with as much sugar, salt, and fat as they can, because the more we like them, the more money they make. Our brain is programmed to make us like those things that were hard to get so that we'll work to get them, but this backfired, because we worked so hard that it's now too *easy* to get them and we get sick. See, humans are intelligent and *lazy*. We use our large brains to make life easier for us when we evolved from animals whose lives were hard and whose bodies were optimized life being hard. We're too smart for our own good, we humans."], "text_urls": [[], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], ["https://www.scientificamerican.com/article/its-time-to-end-the-war-on-salt/"], [], [], [], [], [], [], [], [], []], "score": [9455, 5633, 2047, 235, 81, 53, 51, 49, 48, 45, 36, 23, 14, 12, 11, 11, 11, 11, 10, 9, 8, 6, 5, 5, 5, 5, 4, 4, 4, 4, 3, 3, 3, 3, 3, 3, 3]}}, {"q_id": "5xvfbb", "category": "Repost", "title": "Why does a lack of sleep give people bags under their eyes?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dela5zg"], "text": ["It's the extended strain on your facial muscles from having to keep your eyes open for longer than they normally should be open. Note: this isn't the *only* reason for eye bags/circles, it's also genetics, dehydration, allergies, and too much sodium."], "text_urls": [[]], "score": [23]}}, {"q_id": "5xxhzo", "category": "Repost", "title": "Why are larger objects often depicted as moving in slow motion when viewed from the perspective of a smaller objecr?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dellxr2"], "text": ["Because large animals like elephants move more slowly than small animals like dogs. If an elephant moved at the speed of a dog, the forces involved would exceed the strength of the materials an elephant is made from."], "text_urls": [[]], "score": [5]}}, {"q_id": "5xyh83", "category": "Repost", "title": "What exactly is sleep? And why do we do it?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["delzqeh"], "text": ["Sleep is the brain's \"clean\" cycle. Your brain cells aren't connected directly to the bloodstream. There's a barrier in the way, the *blood-brain barrier*, that prevents random chemicals in the blood from affecting brain function. You wouldn't want your personality to change based on what you had for lunch, for example. This means that the brain cells need some other way to get nutrients and dispose of their waste. So they use the *cerebrospinal fluid* (CSF). CSF is a nutrient soup that surrounds and fills the brain. It flows slowly through the brain, and nutrients float around in it to be absorbed by the brain cells. But those cells have to expel waste - they expel their waste into the CSF, too. And the CSF doesn't flow fast enough to really carry that waste away, so it just sits there, building up. By the end of the day, the cells are basically floating in a soup of their own waste products, which is bad for brain function. So the brain enters sleep mode. During sleep, channels around the brain open up. The day's old and grimy CSF is pumped out, and fresh CSF is pumped in, flushing away all those waste products. By morning, you wake up with a squeaky-clean brain."], "text_urls": [[]], "score": [10]}}, {"q_id": "5y1b8e", "category": "Repost", "title": "Why does bright sunlight make people sneeze?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["demeptu"], "text": ["Other light should be causing it. It's a reaction that some people have called the [Photic Sneeze Reflex.]( URL_0 ) It's similar to an allergy in that if you take antihistamines, it reduces the light's effects."], "text_urls": [["https://en.wikipedia.org/wiki/Photic_sneeze_reflex"]], "score": [3]}}, {"q_id": "5y1cfi", "category": "Repost", "title": "Why do guys have morning wood? And is there a variation of it for girls?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["demm9ex", "demiolc", "den98cp", "den1g26", "demkfn7", "demxggn", "denl4d2", "denppzo"], "text": ["Erections are stimulated by the parasympathetic nervous system causing Nitric oxide release within the corpora. This pro-erection process is counter-balanced by an anti-erection effect from the sympathetic nervous system. Normally, they cancel each other out. The Sympathetic nervous system activity dips in the small hours whilst you are asleep and the parasympathetic effect 'wins'. Coupled with a normal diurnal rise in testosterone levels; you get a stonking boner. Source: Urologist", "This other poster is incorrect, it has nothing to do with the bladder pressing on the prostate. > the absence of norepinephrine during the REM phase of the sleep causes erections. In women, this phenomenon is called Nocturnal clitoral tumescence while it is called Nocturnal penile tumescence in men. Considering women have a similar phenomena, and dont have a prostate....it should be fairly obvious that this has nothing to do with a prostate... URL_0 EDIT: Note that there is apparently some debate as to the exact reason for morning wood. The stimulation of the prostate is from a sentence on Wikipedia where citation is needed. While the cause is not entirely known, stimulation of the prostate is absurd", "The female equivalent is referred to euphemistically as \"morning dew\", because the female equivalent is unplanned lubrication.", "Though it is less common, women experience something similar! When aroused the clitoris has increased blood flow, and women can wake up with this still happening.", "Before I became sexually active (with anyone but myself) especially as a teenager, I would have REALLY sexual sensations in my dreams. I wouldnt necessarily come during these dreams, but because I was pretty sexually frustrated my body would begin the sexual arousal process in my dreams. So, this is equatable to morning wood.", "Sometimes I wake up to me humping my mattress...that's my morning wood i guess?", "Girl here. We may not have the same physical \"wood\", exactly, but yes, clitorises get hard. But I often wake up earlier than my partner and fade in and out of horny sleep until we're both awake enough.... by the time he wakes up I'm so damn ready. My understanding is that estrogen levels increase in early waking hours, which makes sense, because i come so much harder from morning sex. So, yes, i get morning wood. Very much so.", "I remember once hearing an explanation that was obviously just a joke but it always stuck with me. And it was basically that nobody really knows why we dream, or where dreams come from, so maybe an erect penis is actually an antenna where we receive our dreams."], "text_urls": [[], ["https://www.google.com/webhp?sourceid=chrome-instant&amp;amp;ion=1&amp;amp;espv=2&amp;amp;ie=UTF-8#q=female+morning+wood&amp;amp"], [], [], [], [], [], []], "score": [1057, 436, 97, 25, 23, 16, 15, 5]}}, {"q_id": "5y2cy1", "category": "Repost", "title": "Why is telephone hold music still so shitty?", "title_urls": {"url": []}, "selftext": "Even though voice audio quality has definitely improved, it seems like all hold music still has serious issues with static, volume control, \"tinny-ness\", etc. Why can't we apply the same methods to the music as we do to the voice?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["demlt60"], "text": ["There's actually an optimization in use to keep the data usage down. Audio encoding methods we normally use for music can handle a wide range of frequencies. However, because the human voice only has a limited range (and we usually speak in only a small slice of that) the audio encoding system used on phone lines doesn't bother to properly encode highs and lows, making songs sound like ass but saving data. If we switched to a better encoding system, it'd mean more data traveling over the same phone network, which'd put more strain on the network and probably lead to the phone companies charging everyone more to carry it. So we decided to just deal. It's not like the hold music is **good** music even when you can hear it properly, right?"], "text_urls": [[]], "score": [5]}}, {"q_id": "5y36bd", "category": "Repost", "title": "why does a wooden spoon prevent a pan from boiling over?", "title_urls": {"url": []}, "selftext": "In use this LPT a lot (placing the spoon horizontally across the pan, under the lid), and it works perfectly. So what's the science / witchcraft?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["demsxu6", "demsj8p", "demsozc"], "text": ["Two main reasons: 1. The rough surface of the wooden spoon will break the water bubbles, causing the foam to break around the spoon. 2. The contents of the bubbles is mostly steam, and when it comes into contact with the room-temperature spoon the steam condenses into liquid water. This hack isn't a complete fix though, and will stop working when the spoon gets saturated with water or reaches a similar temperature to its surroundings.", "The bubbles are little pockets of air that push up off the water. When they interact with a smooth object, like the side of the pan or the lid, they don't pop very easily and can overflow the top of the pan. A wooden spoon is not smooth, it is course and has tiny pits and gaps and ridges. This helps pop bubbles as they come up, preventing them from running over the top of the pan.", "Two reasons. One is that the spoon causes the bubbles to burst by breaking surface tension. You could sit there and rapidly poke bubbles and this would have an effect, too. Second, the wood spoon is at room temperature and is able to absorb some of the heat - not much, but just enough to help (this is why a metal spoon won't work). You can also blow on the bubbles which will both decrease their heat and pop some of the bubbles. It doesn't actually work perfectly, though. If it's boiling rapidly enough, it'll boil over anyway. As an aside, if you do this enough with a wooden spoon, it will also warp it."], "text_urls": [[], [], []], "score": [3, 3, 3]}}, {"q_id": "5y4l89", "category": "Repost", "title": "Who's in charge of coming up with street names and is there any approval by a committee? Also, if you were someone that decided street names how did you come up with them?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["den4ljg", "denj8e0"], "text": ["In private developments in Ohio, it's up to the discretion of the developer. For example, the development I live in AND the street I live ON are both named after the developer's grandson... who lived in the development. The development I used to live in was interesting because every street was named after a winner of the Kentucky Derby. I would guess that the county commissioners name the public streets. This is probably different in all fifty states and I'm sure it's different in other countries.", "I am not sure how heavily it's enforced anymore, but I believe that here in New Zealand the type of road (Street, Avenue, Road, Lane etc) used to be (may still be?) dictated by features of the location, while the unique part at the start was up to the land owner. I've always wanted to see a place called Lois Lane"], "text_urls": [[], []], "score": [8, 3]}}, {"q_id": "5y5w65", "category": "Repost", "title": "What is it about corn syrup that makes it so bad? What is the difference between it and other forms of sugar?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["denfv21", "denhs3u"], "text": ["The biggest problem with (high fructose) corn syrup has nothing to do with it's chemical differences from pure sugar, it's about the economics and ubiquity of it. Due to the massive subsidies the American government gives the corn industry, the cost of HFCS is ridiculously low. People have sweet tooths so we're drawn toward eating sweet things. When the cost of sugar is artificially low, that creates incentive for manufacturers to use lots of sugar in *everything* we eat which means we're eating more sugar & consuming more calories. This leads to weight gain & the obesity epidemic.", "There are real difference between high fructose corn syrup and glucose (another form of sugar) and how they affect satiety, or how satisfied you feel after a meal. That feeling of satiety comes from leptin, a chemical released from fat cells that signals the hypothalamus that you've had food. Fructose has been shown to have a much smaller level of leptin release than glucose after consumption, meaning that the \"I've had food!\" signal is a lot weaker, so you tend to consume more food. If fructose is the soda of sugars, then glucose would be your balanced meal! There are also a ton more differences between the different types of sugars and how they are absorbed and used for fuel by your body! Definitely good information to know while trying to be health conscious!"], "text_urls": [[], []], "score": [5, 4]}}, {"q_id": "5yb7k3", "category": "Repost", "title": "How will the economy still function when automation takes the majority of jobs and nobody has money to purchase anything?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["deomld7", "deomqgv", "deorucl"], "text": ["Automation taking the majority of jobs will quickly lead to an economic situation called [post-scarcity]( URL_0 ), where the majority of people's needs and most of people's wants will be satisfied at little to no cost. The capitalist economic system you're familiar with, with free markets and money, is fundamentally incompatible with post-scarcity. A new economic system will take its place.", "In its current state, it won't. This is a crucial issue for millennials because it is our future that is at stake. Many will be without work unless they are in a skilled trade, or work in the must haves(IT, nurses, teachers, etc). Any uneducated labor will have no place in the modern world. Many other countries are trying things like minimum income, widened welfare, etc but those methods are ideologies that do not bode well in the United States as we tend to be more of a 'you get what you earn' culture. Countries like Germany have completely revamped their educational system in an effort to reduce this mass group of uneducated people, but the long term results are still yet to be seen. The places hit the hardest are going to be urban areas. Unfortunately the answer that many people are given is goto college but that doesn't work for everyone and presents its own problems such as being saddled with student debt. There are over two million jobs available in the skilled trades but unions and companies have a hard time finding quality candidates. Instead a different form of slavery is being pressed upon the youth of this nation, one from which they can never escape. I said this was an important issue because it is, but there are so many other variables out there that could cause any solution to fail. Leaving the top 1% and the skilled with jobs hauling the uneducated masses. I don't have a solution, but I know where our obstacles are. This has been something I've thought about for sometime. Maybe one day I will create a plan for it.", "Automation has already taken the majority of jobs. 200 years ago, 90% of people worked in agriculture. It has been automated so heavily today that number is only 2%. Did 88% of people lose their jobs? Not really. New jobs are created by new technology. Technology/automation is actually the driver of our standard of living in the long run. [See the Solow Model]( URL_1 ), which is taught to every economics student at the intermediate level. In the long run it is actually the destruction of jobs that boosts our wealth, it allows us to produce more with less people, dropping the price of goods. Automation really is a non-concern for economists. I shouldn't say that, because many economists are actually very concerned with it, concerned with encouraging it! Don't believe the fear mongering. Historically, people are always pessimistic about the future. You can say \"oh, but AI is different!\" the response to this is: 1. You can construct a model where humans are capable of producing only 1 or 2 goods, and automate them. Humans will still benefit from this and reach full employment. 2. If truly all jobs today and in the future were to be automated - everything would essentially be free, making this a non-issue. We would be so insanely wealthy, even a miniscule portion of GDP dedicated to social welfare would make the average welfare recipient as wealthy as the average 1%er today. [See this classic piece on the subject by a nobel prize winning economist]( URL_0 )"], "text_urls": [["https://en.wikipedia.org/wiki/Post-scarcity_economy"], [], ["http://www.slate.com/articles/business/the_dismal_science/1997/01/the_accidental_theorist.html", "http://www.pitt.edu/~mgahagan/Solow.htm"]], "score": [7, 4, 3]}}, {"q_id": "5yc575", "category": "Repost", "title": "would eating 24,000 calories at once result in more weight gain than the food weighs?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["deoun5q"], "text": ["> Doesn't that violate the Law of Conservation of Mass? No, because the fat cells are also going to contain water which the person is assumed to be drinking as needed."], "text_urls": [[]], "score": [4]}}, {"q_id": "5yep76", "category": "Repost", "title": "How does a record player work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["depe23l"], "text": ["Very simply (please don't add on to something here. It's explain like I'm 5, not a PhD ) The record as small groves on it that the plastic piece travels through as the record spin. The groves are jagged and curved to give off certain sounds, which are amplified by a speaker. Newer ones instead hooked an electric pulse on the other end of the stick, plugged into a speaker where the electricity moves the magnet inside the speaker and vibrates the plastic/paper cover of the speaker. Now you know how a record and speaker work."], "text_urls": [[]], "score": [9]}}, {"q_id": "5yewdj", "category": "Repost", "title": "When your phone is plugged into the wall, electricity is moving through the cable. If the charger is left plugged into the wall with nothing attatched to the end, how come it doesn't shock you when you touch the end, or catch fire when left unattended?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["depfbwu"], "text": ["The adapter changes the voltage from whatever it is that you have in your country to about 5 volts. A laptop might be 20 V. The electrical resistance of a human body (dry) is 100.000 Ohm, more or less. If you were to connect perfectly to the 5 volts and close the circuit (which you don't), and you were dry (please, don't do this right out of the shower) electrical current will pass through you: I = V / R = 5 Volts / 100.000 Ohm = 0.05 mA. Threshold of sensation is 1 mA. [Death is around 0.2 ampere (200 mA). Don't play with electricity.] But, again, you don't really close the circuit. Air is in the way. Air has an even higher resistance to electrical current. You need thousands of volts to make electricity travel through it (we call that lightning). It's closing the circuit (air is everywhere) with an insulator. That's why the open end charger doesn't catch fire."], "text_urls": [[]], "score": [5]}}, {"q_id": "5yezfw", "category": "Repost", "title": "What happens to all the cancer cures in the news? Where do they go?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["depfmtm"], "text": ["They sensationalize minor breakthroughs. So for example, say the process to develop a full blown cure for a specific type takes 100 steps. They finally unlock step number 38, which was really complicated and exciting to overcome for the scientists. But the news reports it like it only takes one step and finally a cure is here...well no. There are still a lot of other issues to overcome."], "text_urls": [[]], "score": [4]}}, {"q_id": "5yg49m", "category": "Repost", "title": "How does CRISPR and Cas9 work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["depslj6"], "text": ["Hey ! The question has already been asked [multiple times]( URL_0 ) so you might wanna go check these posts you'll probably find what you're searching for :)"], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/search?q=crispr&amp;restrict_sr=on&amp;sort=relevance&amp;t=all"]], "score": [5]}}, {"q_id": "5yjmei", "category": "Repost", "title": "What is happening when people experience voices in their head?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["deqn5pl", "deqqqld"], "text": ["The first thing to know about hearing is that it is mostly processed within the temporal lobe of the brain. This part of your brain lies just inside your ears. Scientists discovered that certain regions of the left temporal lobe are more active during an auditory hallucination, as compared to when a patient is not hallucinating. When one talks, their brain tells itself that it's talking, now, and that they must be talking to someone else. In studies of this nature, scientists have concluded that the brain signals originating in speech-generating regions of the brain were not bothering to tell the auditory regions that the forthcoming thought was actually self-generated. If the auditory part of the brain does not expect to hear its own voice, then any voices that are heard MUST belong to someone else. The actual problem, which was discovered, is an anatomical error within the fiber bundle that connects speech-generating areas in the frontal lobe with auditory cortex in the temporoparietal lobe Essentially, if you do not know with certainty that you are speaking then you will assume that the voices are talking TO you.", "I use to run an interprofessional club at school, one of the workshops we did was about mental health. We did this one activity where we had a bunch of iPods with this audio stimulator to somewhat understand or experience the voices in your head. We had members walk around the school, speak to friends, get food or a coffee, just typical student activities while listening to the stimulator. If anyone felt uncomfortable they were free to stop anytime. It's a very interesting experience. Here is a popular audio stimulator from YouTube if you'd like to try it out, URL_0"], "text_urls": [[], ["https://www.youtube.com/watch?v=0vvU-Ajwbok&amp;sns=em"]], "score": [17, 4]}}, {"q_id": "5ylwrz", "category": "Repost", "title": "why foods taste so different when hot vs cold?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dercnt2"], "text": ["I have a degree in food science and this was a very interesting topic to me. I'll try to answer to the best of my ability while keeping it simple. The first reason relates to how you actually taste things. The way we perceive taste is actually a combination of our taste buds and our nose working. Taste buds send a signal to the brain when food touches them. But your nose is also very important. You have probably experienced the decrease in taste perception when you have a cold or stuffy nose. There is a passageway in the back of your throat called the retronasal route that leads into your nose. So when the food hits this spot, you essentially \"smell\" it from inside your mouth, and this adds another layer to flavor perception. Different food flavors volatilize, or become airborne (smellable) at different temperature. You will notice this when you cook. As you pull the ingredients out of the fridge they might have some odor to them, but once they are all in a pot together cooking the smell is amplified and starts to fill the whole house. In the same way, you will essentially \"smell\" hotter food through the retronasal route in your throat more than colder food, because the flavors are more airbourne. There is also an interesting link between temperature and taste. In studies, people tend to perceive spicy foods as less spicy when they are cold. If you keep your hot sauce in the fridge, you will notice this. This is probably due to the reasons I explained above."], "text_urls": [[]], "score": [18]}}, {"q_id": "5ymsmn", "category": "Repost", "title": "Why are all the planets spherical?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["der945a", "derf1b4", "der97p6", "dergg47", "dercoep"], "text": ["Gravity. When something has enough mass, the gravity from the center will pull equally in all directions. This will make a sphere. In the case of planets \"mostly spherical.\" Something like an asteroid doesn't have enough mass to \"crush\" itself into a sphere, so they can take many shapes. One of the requirements of being called a planet is that it is spherical (to a certain degree).", "Imagine you had a non-spherical object the size of the earth (let's say, it's a Cube instead) Well, in that case, certain parts of the cube (the corners) would be farther away from the center of mass than other parts (the center of the faces). Because the corners are farther away, they have more potential energy (the same way a brick on top of a building has more potential energy than the same brick resting on the ground). Now Gravity is trying to crush everything into the center (it's just what Gravity does, attracts mass towards other mass), the areas with higher potential energy have a higher likelihood of 'Falling' from their elevated position to a lower 'Rest State'. As this 'Falling' action occurs (over vast periods of time), your Cubic-Planet would crush itself into a Spherical-Planet, where all points on the surface experience the same gravitational force. (Sidenote: other's have already pointed out planets aren't spheres, they're spheroids. This is because the rotational energy counteracts gravity more at the equator than at the poles)", "Well they're not really spherical, they're kind of compressed spheres. Essentially what happens is that in a sphere, everything is as close to the gravitational center of the planet as possible. If you had, say, a cube, then the corners would stick out, and tend to be pulled back toward the center of the planet over time. Essentially the same force that makes a mound of sand unstable and likely to spill down makes planets roughly spherical.", "Gravity pulls planets into a shape that has the lowest surface area; to mass ratio, which is a sphere.", "First look [at this video]( URL_0 ) of water in space. The lack of gravity makes the water spherical because the forces inside the water itself are enough to keep them together and nature always choose the less energy shape to keep something that is in equilibrium that, in that case, is a sphere. Because the planets are rotating, they are not really a perfect sphere. Earth for example is larger at equator because the speed is bigger there and trends to make the whole thing expand a little bit. In fact, earth's south half is larger than the north one. So earth is like a pear but the differences between all parts are minimum, just detectable thru instruments."], "text_urls": [[], [], [], [], ["https://www.youtube.com/watch?v=ntQ7qGilqZE"]], "score": [308, 66, 14, 5, 5]}}, {"q_id": "5yn0ol", "category": "Repost", "title": "Why do computers slow down over time?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["derccon", "derdwv1"], "text": ["Slowing down is not always the problem. A lot of it is caused by newer software/websites require additional resources that weren't so easily available back when that computer was designed so it makes it seem slower. There is also maintenance that people forget about; I've seen tons of computers that have so much bloatware installed using resources for no reason. Rarely it will be the actual computer slowing down. If you don't dust often the insides can get hotter than needed and cause long term damage that can lead to a slower computer. I hope this answers your question.", "No. I personally do not think it's something that can be simply fixed. The computer slowdown is mainly because you keep filling more programs and files into it. They start to fill up your memory. Some of the programs that you install run theirselves in background, which makes the computer allocate some of the resources to run it. For example, the Skype app defaults to start when you start your computer. That can make your computer slower to turn on and also slow your computer down realllyyy slightly even when it's on standby. Because, the Skype app needs to listen to incoming calls when you're logged in. It needs to keep updating the status of your friends, so you don't have to see the loading screen everytime. This consumes a small amount of processor, memory (RAM), and disk resource. Examples of other app would be Antivirus. They also run updates, scans, and their stuff even when they're on standby. Now, one application might not be that big of a deal, but it all adds up when you install a lot of applications. When RAM starts to fill up, things may get really slow. RAM is the memory used to store currently running program. It's basically the difference of a Skype app lying in your desktop, but unopened, thus not consuming RAM, and the opened Skype app after a loading screen (from the disk). After a brief moment of loading, the application will always be ready for you to use even when it's minimized, until you exit it by yourself. The Skype app is saved in RAM. If the RAM fills up, then they need to start closing programs, do memory compressions, and sometimes use some of the disk to help the RAM! Disk is slower, by much, than RAM is. Another might be disk activity. Usually applications like antivirus checks your disk now and then. Even many other applications do their minor disk check / write every now and then. If you use a Hard Disk Drive (contrary to SSD), the read/write operation is going to get really slow. Imagine a really big room and you need to take/put items from one edge, and then the other edge, and then in the middle. You will need to move a lot, unless if it was located in the same place. Hard Disk Drive (HDD) only has one arm per platter, like CD readers, that's why I somewhat crudely used this analogue. This analogue is what is usually called, in computer terms, 4K Random Read/Write (scattered files) and Sequential Read/Write (when the files are in one place). Random Read/Write is where SSD excels by a lot, because they're mostly wires and chips. You can split the workload between a lot of chips easily, but it would be impractical for use in a HDD because a platter needs its' own share of components and making it really small so that a HDD can hold a lot of platters to multiply the speed would not be beneficial. Some programs also consume processor time, when they need to process data. Now, if you ask on how to fix them, I'd recommend upgrading your PC so that you won't really notice the slowdown even after you have installed many programs. Also, uninstall programs that you deem not necessary, and delete your really unused files (so that SSDs can do better garbage collection and HDDs can defrag faster, but the performance gain is miniscule). I'd start by recommending SSD upgrade! Since many of the slowdowns I saw, as far as I know, are disk-related."], "text_urls": [[], []], "score": [7, 3]}}, {"q_id": "5ypx4k", "category": "Repost", "title": "Why do we have fingernails?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["des0hap"], "text": ["We evolved from animals that had claws. Wikipedia cites a few functions: to protect the soft tissues at the end of the digits, to enhance sensitivity of the fingertips by causing counter-pressure when the fingers press against something, to act as tools for precision pinching, and to be used for cutting or scraping certain things. It is thought that broadening of the nail went along with broadening of the finger that allowed for primates to grip small branches more easily."], "text_urls": [[]], "score": [3]}}, {"q_id": "5ypzhc", "category": "Repost", "title": "Why isn't sales tax included on American price tags?", "title_urls": {"url": []}, "selftext": "It seems as though in most other countries it is quite rare for the price tag of something in a store to not include taxes, why is the same not true in America? Yes, taxes vary state to state but why does that make it 100% impossible to include it?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["des0orx"], "text": ["Keep in mind that taxes don't just vary by state, they also change by county and by town. A lot of companies want to set the price for their product, including by printing it on the product. It really just becomes a burden by having to do different prices by city."], "text_urls": [[]], "score": [3]}}, {"q_id": "5yq2q1", "category": "Repost", "title": "Borderline Personality Disorder", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["des25lo"], "text": ["My mother has borderline personality disorder so I've done a shitload of reading on it. What it is at its core is a complete inability to regulate your emotions. Every emotion that you feel is turned up to such an intensity that it is just unbearable for the feeler. And that phenomenon of strong emotion is combined with a lack of formed identity in your brain. People with BPD have a really unstable sense of self. They don't feel like complete people on their own. They feel non-existent or like their identities are constantly shifting. So they tie themselves to other people and fix themselves to their identity which helps for a while. But then they become absolutely *terrified* that the person will abandon them, which means they will lose their identity. And that feeling gets ramped up to 11, and this establishes the push-pull dynamic that is typical of BPD. \"I hate you, don't leave me,\" is the title of a very popular books on BPD. What causes it? Most people with BPD have really chaotic or abusive childhoods that seemed to lead to their unstable sense of selves. If you figure out who you are based on other people's reactions to you, but then those people don't have consistent reactions, how do you figure out who you are? Your young sense of identity gets screwed up and that carries later into life. How do you identify someone who has it? You can armchair diagnose by evaluating whether they have the [9 symptoms of BPD]( URL_0 ), but really that's something that should only be done by a professional. I think it's important to state that BPD is treatable, and many people these days have profound success with DBT, dialectical behavioral therapy. Treatment is rigorous and has to take place over a number of years, but people with BPD can have stable, happy lives with some work."], "text_urls": [["https://www.helpguide.org/articles/personality-disorders/borderline-personality-disorder.htm"]], "score": [3]}}, {"q_id": "5yqx9d", "category": "Repost", "title": "why are ancient civilizations buried underground?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["des9eqp"], "text": ["It depends on the environment, honestly. Not all ancient ruins are actually underground. But there are a few factors that are important, as far as I understand it: *Wind*: consider that the wind is constantly blowing around tiny bits of sand and dirt, along with leaves and other things. You might not notice them over the course of a year or so, but after a hundred years of not being lived in, things start to pile up. *Erosion*: untended buildings don't tend to survive hundreds of years. Weather wears them down even stone can be slowly worn away over a long period of time. What we find are often crumbling remains 'close to the ground' so the speak. 100ft tall buildings aren't being burried. Additionally, things burried under dirt or shielded by other natural things tend to be much better preserved than things exposed to the elements. There are certainly huge numbers of things destroyed by the elements long before we could ever have found them. *Human action*: human civilizations sometimes built stop each other. What is easier: eating land for your own city or town, or building in the ruins of one already cleared? Also, often things we find are burried remains of animals and pottery and the like. These things may have been burried on purpose by the people. Most notably, people bury *other people* usually. We can find the bones of the ancients from their funerals."], "text_urls": [[]], "score": [3]}}, {"q_id": "5yqzf0", "category": "Repost", "title": "Why does the voice in our head sound like our voice but isn't actually audible?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["des9fal", "desj43f"], "text": ["Actually, the voice in our head is whatever we make of it. We can mimic anyone's voice, but we usually use our own because it is us that thinks our thoughts, not someone else. If that makes any sense.", "Google subvocalization. Some people have it, some people don't. A lot of people who have this constant voice accompanying thought think that it is universal. It isn't."], "text_urls": [[], []], "score": [7, 3]}}, {"q_id": "5ysdwg", "category": "Repost", "title": "Why are screeching sounds so annoying?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["desli7s"], "text": ["There are only a couple of things that make a screeching sound in nature: birds of prey, crying babies, and a human scream. Evolutionarily, these either induce terror (because some part of our brain remains from when large scary birds used to eat us) or alarm (is our baby in danger? Is that person screaming because danger is nearby?) But since we need to hear them, our ears and brains are very sensitive to those frequencies, and we hear them as irritating, because if we didn't, we or our children would be more likely to die. Nails on the chalkboard, forks on plates, etc. all make a sound in roughly the same frequency range. Since this frequency range is never a good thing in nature, even when we know things are safe, and especially due to that increased evolutionary sensitivity, our brain finds it to be very unpleasant."], "text_urls": [[]], "score": [11]}}, {"q_id": "5ysho5", "category": "Repost", "title": "how does the switch thing on a rearview mirror work to make lights behind you dimmer, just by changing the angle of the mirror?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["desk4d0"], "text": ["Unlike common mirror, where the glass and the reflective coating on the back side are parallel, in the rearview mirrors the glass has an angle, like the cross-section of the glass is not a very thin parallelogram like any mirror, but is in fact a triangle. This way, the front of the glass is not parallel to the reflective coat in the back. You can see this in this diagram: URL_2 When you have the mirror in \"day\" mode, what you see is what gets reflected in the coating, like any other mirror. When you tilt it to \"night\" mode, you end up seeing what gets reflected on the *surface* of the glass, not on the reflective coat (that light just shines above your eyes) like this: URL_0 Because the reflection on the very surface of the glass is a lot dimmer than the one in the reflective coat, you see the lights of the cars but it doesn't bother you as much. If you watch with more attention, you can see that in night mode you end up seeing the roof of your car in the reflective coat, but because the roof is just very dark, it doesn't interfere with the glass reflection. For another explanation if mine is not so good (I'm not a native English speaker), see this: URL_1 Regards!"], "text_urls": [["http://www.edu.pe.ca/gray/class_pages/krcutcliffe/physics521/17reflection/definitions/rearview.bmp", "http://www.edu.pe.ca/gray/class_pages/krcutcliffe/physics521/17reflection/articles/rearview.htm", "http://www.edu.pe.ca/gray/class_pages/krcutcliffe/physics521/17reflection/definitions/rearview%20day.bmp"]], "score": [59]}}, {"q_id": "5ysht0", "category": "Repost", "title": "the root differences between all different facets of Christianity like Protestant, Catholic, Evangelical and other?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["desl6ow"], "text": ["So there are 3 main branches of Christianity: Catholics were more or less the original. They believe that Peter, one of Jesus' disciples, was put in charge of the church. His successors are the Popes, and they believe the Pope to be God's representative here on earth. They don't worship him, they just think he has a really good idea of what God wants and so he's in charge of the church. The Orthodox Church is really big in Eastern Europe. They split off in the 400s over some very minor-sounding technicalities, and they that they are in fact the real church, descended from Peter, and that Catholics are wrong. They're based in Constantinople instead of Rome. Their beliefs are fairly similar to Catholicism, but they don't listen to the Pope. The Protestants are every other kind of Christian you've ever heard of. Basically, Protestant just means \"not Catholic.\" They split off in the 1500s because the Catholic Church had gotten really really corrupt and was way too involved with making money and political affairs. So Martin Luther founded his own church in Germany (Lutherans), and Henry VIII founded his own church in England (Church of England/Anglicans). Their beliefs aren't terribly different from Catholics nowadays, but they also don't listen to the Pope. They also stress more of a direct relationship with God, so they are less likely to pray to saints to intercede with God on their behalf, and they don't need to confess their sins to a priest, they do so directly to God through prayer. Notably, in response to the whole Protestant thing, the Catholic church changed itself quite a bit in order to correct some of the really weird stuff they were up to, this was called the Reformation. After things started splitting, they got really carried away. Thousands of Protestant sects appeared and usually disappeared. Some have survived. The Church of England came to America and renamed themselves Episcopalians. The Methodists later formed as an offshoot of them. The Evangelicals aren't necessarily a particular denomination, but a movement that grew out of Protestantism. During the 1700s, there was a huge revival of religion in America and Europe, and people started getting into a more \"charismatic\" style of Christianity, rather than the very calm and ritualized Catholic style. Speakers were fiery, and stressed an intense personal relationship with God and especially the need to be \"born again\" into life as a Christian. Rather than the very regimented education system for priests that had previously been taken, pastors started sprouting up all over the place to fuel the demand for this intense new religion, and rather than an organizing structure of rituals like the Catholic church, they stressed going back to what was actually written in the Bible, rather than tradition. Of course, this was as open to interpretation as anything else, so millions of churches sprung up, some of whom believed similar things, and some that were really off-the-wall (like handling venomous snakes to prove your faith. Some of the ones who agreed on things formed their own denominations, or kindof took over existing ones. The Baptists, Methodists, and Presbyterians are all heavily influenced by the Evangelical movement. Others just kind of kept their own church going, some of which got really big (like the ones you see on TV)."], "text_urls": [[]], "score": [27]}}, {"q_id": "5ysvsf", "category": "Repost", "title": "Why do we have designated foods for breakfast, lunch and dinner?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["desn73a", "despu68"], "text": ["Thats really a first world/western thing. Most cultures eat the same type of food all day long.", "These answers are terrible lol. I never understood American breakfast habits, even tho I do enjoy them from time to time. Bacon, pancakes, a mountain of eggs, ham.. all that stuff is delicious but it makes for a terrible start for my day. Here in the Middle East breakfasts are usually much lighter than lunches, which makes perfect sense. Just something to start the day. Usually just a little cheese and bread and some tea."], "text_urls": [[], []], "score": [4, 3]}}, {"q_id": "5yttff", "category": "Repost", "title": "Why do pigeons move their head back and forth when they walk?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["desu2g1"], "text": ["Pigeon eyes cannot focus when they are in motion, so they keep their head still as long as possible when walking. When they move it, they move it as far forward as they can, and then hold it stationary as long as possible to maintain focus."], "text_urls": [[]], "score": [4]}}, {"q_id": "5ywehk", "category": "Repost", "title": "How does antivirus software know what to look for when scanning a computer's files?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["detf9kj"], "text": ["They maintain a massive database of known malware and it looks for anything that matches that code. This is why it is important to update your antivirus frequently, as new malware is discovered, it is added to the database."], "text_urls": [[]], "score": [3]}}, {"q_id": "5yx6sz", "category": "Repost", "title": "Why do we have a permanent human presence in ISS, and want one for mars, but not for moon?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["detm3x4", "detm4rh", "detmqju", "detpfln", "detvg5z", "detwj1s"], "text": ["We use the ISS to conduct experiments, usually centered around how things react in micro-gravity. The moon has enough gravity that it wouldn't serve this purpose. This along with the moon being pretty dull means we know all we need to know about it. Mars on the other hand has resources and could possible support human life. We could theoretically live there long term, which could proof useful seeing how the earth is gonna reach its maximum occupancy soon. Meanwhile, the moon is a boring rock with very little promise for supporting any life.", "There is water on mars so it's easy to imagine a future where humans can live and thrive on that planet. The moon doesn't offer that. ISS is basically the same as a moon base would be only it won't take three days of space flight to get there.", "Because we more or less (with exception, ofc) did most of the things we wanted to do on the moon. Basically, been there, done that, now let's go to Mars.", "I'm no expert but let me try to answer this question the best I can. Mars is the preferred over the moon for an extraterrestrial colony because of several reasons - It has an atmosphere. The moon doesn't. Mars's rotational cycle is around 24 hr 40 min, which is pretty close to an Earth day. This means that our plants will find it easier to adjust. If we want a permanent colony on an off-world rock, a launch facility is a must. Mars is rich in iron and the atmosphere is filled with carbon dioxide and oxygen-which can be used to produce rocket fuel. I'm not a native English speaker so I apologize for any grammatical errors.", "The moon is really, really far away. It is not even comparable to the ISS so logistically it may not be possible now. That said, the moon is also much, much closer than Mars so it isn't as exciting. This makes it harder to get funding since we've been there and it was supposedly not even worth going back when the Saturn program was launching every six months. Starting Saturn over from scratch would be extremely hard and needs the kind of enthusiasm that Mars exploration generates. On a side note, the moon is actually much more diverse in content than was believed until the Chinese got some rocks of their own. It seems that, through some coincidence, all the different Apollo missions landed on similarly composed areas leading to a false impression that the moon is \"boring.\"", "Because there is already a permanent presence on the dark side of the moon. It isn't human. But we know him as Santa Claus. He has a number of operations running up there."], "text_urls": [[], [], [], [], [], []], "score": [56, 10, 5, 5, 4, 3]}}, {"q_id": "5yx9sz", "category": "Repost", "title": "What's the difference between Sunni and Shia?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["detmj1u"], "text": ["After the death of our Prophet Muhammad (Peace and blessing on him), some believed that the leadership of the Islamic community should go to someone in his bloodline. Others believed that those who were closest to him and who learned the most from him and whom he trusted most should lead the Muslims. The former (bloodline people) were the Shia. The second were the Sunni. Over the centuries, more ideological differences popped up but I'm not 100% sure of all of them, but this was the main origin of the schism between the two sects. To be honest, it's all a little outdated and stupid. In some countries, there is still bloodshed over Sunni vs Shia and it's ridiculous. Unnecessary violence. We're all Muslims and we have far greater problems in our community than Sunni vs Shia. We should be getting together to solve the bigger problems our community is facing. Source: I'm Sunni Muslim."], "text_urls": [[]], "score": [15]}}, {"q_id": "5yx9ur", "category": "Repost", "title": "Why does everyone with down syndrome have the relatively similar facial features?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["detnrs2"], "text": ["Down syndrome is a condition of the genes where chromosome 21 has 3 copies instead of two. It happens when there is a problem during meiosis in one of the parents. This causes chromosome 21 to not work properly. As a result certain things that are supposed to happen as the fetus developes, don't end up happening, and the person grows a little differently the he or she otherwise would. Whatever these irregularities are, they are consistent in everyone with the condition, so they all share the same unusual facial characteristics that result."], "text_urls": [[]], "score": [12]}}, {"q_id": "5yxb27", "category": "Repost", "title": "In what way, EXACTLY, is sleep as crucial to human health and fitness as they say it is?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["detmjq7"], "text": ["We dont actually know why we need to sleep. There are a lot of theories ranging from it being crucial to tissue regeneration to it actually changing our brain chemistry. What we do know is that if you go long enough without sleeping organ failure tends to occur within a week or so."], "text_urls": [[]], "score": [12]}}, {"q_id": "5yxk46", "category": "Repost", "title": "what part of my clothes does dryer lint come from?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["detr7vg"], "text": ["It's little fibers breaking off of the threads your clothes are made up of. Slowly, over time with many dryer cycles, the clothes will give up most of the fibers they had, and this is when you start developing \"ratty\" clothing with holes in it, even though you never put enough stress on the clothes to rip them."], "text_urls": [[]], "score": [3]}}, {"q_id": "5yz046", "category": "Repost", "title": "How does travelling near light speed cause time dilation?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["detyjwl"], "text": ["There is a very elegant way to think about this that I think is reasonably accurate: instead of imagining us living and moving around in three dimensions like normal, imagine us in four dimensions, our three plus time, and that everything must always move in those four dimensions at the same speed, the speed of light. If you're not moving at all in space, you're only moving through time, at full speed. As you start moving, your velocity in space is increasing, which would increase your total 4D speed which is the sum of your speed in space and in time. So to keep that 4D speed constant, you have to slow down in time and experience time dilation. (A more to the point explanation will talk about how time dilation is necessary to keep other physics consistent in the context of constant speed of light, but I'll leave ELI5ing *that* to someone smarter.)"], "text_urls": [[]], "score": [15]}}, {"q_id": "5yzr1a", "category": "Repost", "title": "Why does NASA assume that there is no life on planets that has conditions that are not ideal for humans, when the organisms on the planets could have adapted to their respective conditions and thrive?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["deu4wbz", "deu4i6s", "deu4iy9", "deu7dwu", "deu4ywf"], "text": ["Let's say you are walking down the street and dropped your keys. They might have landed in the gutter, or gone down the sewer. Where do you look? You look in the gutter because if they are down sewer, you won't be able to find them. That's the approach organizations searching for life are taking. We know a *lot* about earth like life, and have very good ideas what it might look like from light years away. We know nothing about other forms of life, and might not be able to detect it in our own solar system.", "Because exept for a few very strange occurances, mankind has not observed any form of \"life\" that is able to survive in environments unlike our own. The only thing we know are carbon based lifeforms and we're pretty good at telling how well we can survive our own evironment. We can't be sure of anything that is off planet until we directly observe evidence of the contrary.", "We call \"life\" what we see in this planet. Not necessarily what humans need. There are bacteria that thrive on sulphuric acid. That we know, and if we found a planet that offered the adequate conditions it would be labeled as such. But life (as we know it, human or not) requires ranges of temperatures and pressures that are usually not found \"out there\"", "If you are referring to the goldilocks zone the definition does not mean that conditions are ideal for human life. The definition is that conditions will allow for liquid water. The reason for this is that all life that we are aware of requires liquid water at some level. While it is possible for life to exist without liquid water it is all theoretical as far as I know.", "They don't assume that, it's just a lot easier to search for planets that have ideal conditions for life that we know of then to search for lifeforms we have no knowledge about."], "text_urls": [[], [], [], [], []], "score": [53, 24, 7, 7, 4]}}, {"q_id": "5yzust", "category": "Repost", "title": "How do they actually figure out the nutrition values in food, such as calories, carbs, cholesterol.. Etc?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["deukfat"], "text": ["Nobody has really answered this question yet. I am a food scientist and work at a large food company and we have a certified analytical lab that does testing on food samples. To get the fat% for instance, one popular method is to boil a sample of the food in a non-polar compound like ether. Since fat is also non-polar (opposite of water which is polar) you can remove all of the fat from the product and weigh the difference. For protein you basically extract the nitrogen in the product and use that data to tell you the amount of protein. For minerals, you put the product in a furnace to burn off all of the organic material. Moisture you put the sample in a special oven or microwave and cook off all the water. Carbs is usually done by just calculating the difference of all the components from the mass of the sample. There are other methods like using near infrared detection but I don't know the details of how those work."], "text_urls": [[]], "score": [11]}}, {"q_id": "5z2glv", "category": "Repost", "title": "Why do we get brain freeze?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["deurg1c"], "text": ["From mayo clinic Scientists are still unsure about the exact mechanism that causes this pain. One theory is that the cold food or drink may temporarily alter blood flow in your nervous system, causing a brief headache. Blood vessels constrict to prevent the loss of body heat and then relax again to let blood flow rise. This results in a burst of pain that subsides once the body adapts to the temperature change."], "text_urls": [[]], "score": [3]}}, {"q_id": "5z2p61", "category": "Repost", "title": "Why dont other countries have military bases in the US, While the US has bases in many other countries?", "title_urls": {"url": []}, "selftext": "Can you explain why we have bases in so many other countries while they have none in ours? I caught interest in this when watching a video on the US vs The European Union, and how our militaries match up against each other.", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["deutar2", "deutt2s", "deutif4"], "text": ["The US has a huge military force with the primary mission of projecting force worldwide. Most other countries have comparatively small forces with a mission of only local self defense or regional force projection. Local self defense obviously does not require bases half the world away. Many countries also depend on the US for military protection. The US has always been the backbone of NATO forces, with the other members being a relative footnote. Western European states therefor have many US bases because they depended on US forces to protect them from the USSR during the Cold War.", "It is the result of the end if World War 2. In short, as the war was winding down, Stalin, Churchill, and FDR convened in Yalta in Crimea to discuss how the liberated countries of Europe would be granted self governance. In reality, as the war ended, the Russians already had plans for occupied territories. The UK and U.S. realized this, so it outlined essentially how the powers would be divided as the Cold War commenced at the end of WWII. The U.S. began spreading its military throughout its occupied territories as Europe was rebuilt and subsequently divided across ideological lines. Furthermore, Europe lost a lot of power after the war. As a result, their territories fought and gained independence quite rapidly. Power vacuums were left, and communists, nationalists, republicans, etc. fought for control of their governments. Well, that, or brutal dictatorships developed from offices once regulated by European powers. These nations were easily exploited and/or open to influence from both the Soviets and the Americans. As a result, aid and resources flowed from both the world's superpowers. A lot of countries had resources from either power, especially in the Southeast Asia and some Latin Countries. Because our power and influence was contingent on having control of these countries in some regard, the U.S. stationed basis there. For instance, n Europe, the U.S. had control of military strongholds.", "Well, primarily because the US doesn't allow other countries to, nor do they really want to. Some countries often to take US bases into their territory for two primary reasons, they want the protection of the US or just want something from the US in exchange for a permit to build a base in the country."], "text_urls": [[], [], []], "score": [13, 10, 3]}}, {"q_id": "5z2v1y", "category": "Repost", "title": "Why do we have tax Brackets and not a continuum?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["deuv5sq", "deuuo00", "deuvpwc", "deuvqdb"], "text": ["So it's a \"graduated system\" ELI5 simple: the first $100 you make gets taxed at 0%, the next $900 you make gets taxed at 10%, and the next bracket (anything over) is taxed at 20%. You make $50, you get taxed $0. You make $100, you get taxed $0. You make $200, you pay $0 on your first $100 and 10% on your next $100 so you pay $10, or a 5% rate. You make $1000, you pay $0 on your first $100, and 10% on the next $900, so you pay $90, or a 9% rate. You make $5000, you pay $0 on your first $100, 10% on your next $900 so $90, and 20% on your next $4000 so $800, so $890 in total, which is just under 18%. You're thinking it's You make $50, you get taxed $0. You make $100, you get taxed $0. You make $200, you pay 10% or $20. You make $1000, you pay 10% so $100. You make $5000, you pay 20% so $1000. which is wrong", "No, because when you move into a higher bracket, the new percentage only applies to money over that cutoff line, not to the money under the cutoff line that has already been taxed at lower rates.", "> But in the bracket system, don't you create scenarios where if someone is close to the top of one bracket, and they make a few dollars more in a year, they could end up losing money by being pushed to the next tax bracket and owing a higher percentage? This is false information. The way the tax brackets work is that you are taxed at that percentage for all money earned within that bracket. So if you have $5 in the new tax bracket only that $5 is taxed at the higher percentage.", "So as other's have explained we have a graduated system that ensures that you are not penalized by \"graduating\" to a higher tax bracket. To address the other part of your question, why don't we use an equation... For one reason main reason. Politics. The reason we have tax brackets is to tax different sections of the population differently. These brackets allow us to adjust bracket A without having to do anything to bracket B and C, and then we can move D a bit as well.. Take a look at the tax brackets we currently have, 10%, 15%, 25%, 28%, 33%, 35%, 39.6%...There isn't exactly any rhyme or reason to these percentages and therefore any equation trying to capture this would be wildly complex and pretty damn unwieldy. The downside an equation type system would encounter (which frankly is also a benefit imo) is it is inflexible and would be difficult to change in a political way (raise taxes on the rich, lowering them on the power, and keeping the middle class un-effected)"], "text_urls": [[], [], [], []], "score": [13, 8, 6, 3]}}, {"q_id": "5z3935", "category": "Repost", "title": "Why is every planet spherical?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["deuxyj9"], "text": ["Planets form spheres because of the gravity emitted by their own mass. In space, any mass in space that exceeds about 6x10^20kg, or about 1/10,000 the mass of Earth, will compress itself into a sphere because its gravity pulls all of the mass in. Ideally, this leads to a shape where all the mass is equally distant to the center, or, a sphere."], "text_urls": [[]], "score": [3]}}, {"q_id": "5z4uri", "category": "Repost", "title": "If we get sick because of virus and bacteria, why do we get sick when it's cold?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dev9hdr"], "text": ["Two reasons: 1. When the temperature drops severely, your immune system is more compromised (mostly because at that point your body is focused on staying at 98.6 degrees than it is on fighting off invaders). 2. When it's cold outside, people stay inside more. If you're inside with other people, you're more likely to transmit and/or catch a virus than if you're all outside building a barn or playing frisbee or selling vacuum cleaners door to door or whatever."], "text_urls": [[]], "score": [3]}}, {"q_id": "5z4wrx", "category": "Repost", "title": "Why are there countless numbers of animal subspecies, but no human subspecies?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["deva3vf", "devbkbh", "devhjm2", "devo7wc", "devkrru", "devigrz", "dew5eu6", "devov4k", "dew9fc4", "dew5x1r"], "text": ["Well subspecies is a rather nebulous term. See when a two population of the same species become separated geographically, they won't exchange genetic material through breeding. If they are separated for long enough of put under enough pressure, they will genetically change enough that they will eventually become different species. But it's a long process so you have some population are that in between. Meaning they become different enough that they are clearly not the same species, but didn't change enough to be clearly two different species. But you probably don't talk about that, because there isn't that many subspecies. You probably talk about species that look similar, like how there is like 8 different species of bears. Now it depend on what you consider human. Are human only homo sapiens or all Homo are humans? Because there was something like 16 different Homo Species. Some went extinct by their own, but other were assimilated or killed off by home sapiens. The difference between other animal and us is our intelligence. The intelligence that allowed us to spread to the whole globe very quickly. See usually animal don't spread as much and if they do, it take them a LOT of time. So by the time they reached another continent, they already became a new species. We spread so quickly, that by the time we covered all of the planet we were still the same species and competed with all the other Homo species for resources and we won all over the world.", "All modern humans *are* a subspecies, *Homo sapiens sapiens*. There is an ancestral subspecies also defined, *Homo sapiens idaltu*, and some taxonomies propose classifying Neanderthals as a subspecies of *Homo sapiens* rather than a separate species. A major objection to classifying human racial groups as subspecies is that the variation in smooth and different features vary in different ways. To identify subspecies it's usually expected that there is distinct uniformity within each subspecies and clear differences to the others and that's not the case for humans. Evolutionarily, the ability and willingness of humans to cross all sorts of geographic barriers is probably what's prevented the races from becoming clearly distinct subspecies.", "Depends on your definition of \"human\", but it is not unfair to say that neanderthals were human, or that homo floresiensis or rudolfensis should be considered human. Neanderthals died out 30,000 years ago, and floresiensis were around as recently as 12,000 years ago (with the very first cities being as much as 8-9000 years old, this is surprisingly recent). So you could say that up until very recent human history, there were human subspecies which we interacted with. We even mated with neanderthals. Now, why humans currently are the only ones left is a matter of speculation. It could be that we simply killed off the others, or that we out-competed them in the struggle for resources and food. Or something else. We simply do not know. If you are interested in this and don't want to dig into really hardcore anthropology, I can recommend the book \"Sapiens: A Brief History of Humankind\".", "There are genetic differences between races (indisputable), they are just small because humans spread out so quickly, relative to other animals, once they began spreading out.", "There are many examples of animals where there is only one living subspecies, humans are not unique in this regard. There were other subspecies of *Homo sapiens*, but there are not extinct. We don't consider human races to be subspecies, because in general, there is more genetic diversity within a race than between races.", "There are. Take an Australian Aborigine, A Japanese, A Russian, A Somalian, An Arab, A Native American, An Inuit, and a Native Chilean. One could call the different races \"subspecies\" They all share differences within their subs, but are majority similar as a whole. It's just not politically correct to do this, so you get called a racist.", "There are. Although for political and social reasons western societies don't acknowledge this.", "Because we killed all of them. There used to be a time where there were a few different human-type beings that lived concurrently. Homo Sapiens weren't the strongest of the bunch, rather, we were the smartest, so we were able to conquer the other species of human-like beings.", "There differences that exist between Europeans and Africans are similar in magnitude to those that exist between certain animal subspecies -- say, a sheepdog and a border collie. The fact is that when you divide two populations of a given species by an ocean, they will take on different characteristics. Back in the day, it was normal to classify humans into different subspecies based on observable differences. That's not kosher today, because it's kind of bullshit. But it's not really that much more bullshit than the different classification of certain dogs.", "Because it wouldn't be politically correct. If you look at the different subspecies of African Gray Parrots you can tell that they are physically extremely similar looking, much more so than an African and a European."], "text_urls": [[], [], [], [], [], [], [], [], [], []], "score": [100, 36, 21, 13, 7, 6, 5, 5, 5, 4]}}, {"q_id": "5z5ajq", "category": "Repost", "title": "What is te difference between pansexual and bisexual", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["devcsn8", "devctp8", "devcroj"], "text": ["\"Bisexual\" people are attracted to males and females. The root of the word is \"bi,\" which means \"two.\" \"Pansexual\" people are attracted to males, females, transgender people of all points in the spectrum of transition, and to people who don't closely fit typical gender roles. The root of the word is \"pan,\" which means \"all.\"", "Bisexual is a term people use to identify as being sexually attracted to either genders. Pansexual is a term that is used by people who are attracted to any infinite number of genders or someone who claims to have a lack of gender. For example, if I decided I was a cis gendered attack helicopter it would be rude if you claimed to be bisexual while being attracted to me because my attack helicopter gender is not one of the binary genders. It would be more \"politically correct\" on Tumblr for you to say you are pansexual to show you appreciate my attack helicopter gender identity.", "I have a friend that identifies as pansexual. When I asked her what the difference was, she said that she basically has \"no limit\" on who she's attracted to as she believes there are more than two genders. She doesn't base her feelings on whether they are male or female."], "text_urls": [[], [], []], "score": [7, 4, 3]}}, {"q_id": "5z5m00", "category": "Repost", "title": "Why do some drunk people get belligerent and angry, while others get cheerful and jolly?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["devglp1"], "text": ["> One of the most well-recognized behavioral effects is disinhibition, where behaviors that are normally suppressed are displayed following intoxication. A large body of evidence has shown that alcohol-induced disinhibition in humans affects attention, verbal, sexual, and locomotor behaviors [link]( URL_0 )"], "text_urls": [["http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0092965"]], "score": [3]}}, {"q_id": "5z87cc", "category": "Repost", "title": "What's the difference between an atomic bomb and a hydrogen bomb", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dew1lnc", "dew1hny"], "text": ["An atomic bomb, in the traditional sense of being like the ones dropped on Japan are powered by nuclear fission. Fission is the process of taking one big atom and breaking it down into two smaller atoms, which releases energy. The \"big\" atoms used are heavy elements like Uranium, Plutonium, etc. Hydrogen bombs rely on nuclear fusion. Fusion is the process of taking two small atoms and fusing them together, which also releases energy. The atoms involved are the particularly light ones, like hydrogen being fused into helium. Fusion is the process by which the sun and all other stars work. There is one caveat to fusion bombs - fusion as a process as a relatively high energy barrier. Simply put that means that in order to get fusion to happen, the hydrogen need to have lots of energy before they can fuse. Usually this means they need to be in a very, very hot, environment. Unfortunately the only way we know of to create this environment in a way that can be turned into a bomb is a fission bomb explosion, so most hydrogen bombs have a regular atomic bomb built in to get them going.", "An atomic bomb is any weapon which uses nuclear reactions. A hydrogen bomb is just a specific type of atomic bomb where hydrogen is fused to create an explosion. More specifically, in a hydrogen bomb there is first a fission reaction (atoms splitting) which is used to compress hydrogen to the right pressure for fusion which releases huge amounts of energy."], "text_urls": [[], []], "score": [7, 3]}}, {"q_id": "5z9beq", "category": "Repost", "title": "The Multiverse Theory", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dewb7oq"], "text": ["The basic idea is every single decision any**thing** makes creates multiple universes, each where another outcome was decided. Like if you are walking down a path and it splits into two. As soon as you decide to take one path another universe is created where you decided to take the other. Repeat this for all time since the big bang and you have every single possible universe created at some point. There may be one where a string of decisions made me the president of Mexico! Bow before your president se\u00f1or!"], "text_urls": [[]], "score": [4]}}, {"q_id": "5z9yox", "category": "Repost", "title": "Why do you see shapes and color while rubbing your eyes?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dewhovc"], "text": ["In addition to light, the rods and cones in your retina can be stimulated by pressure. When you rub your eyes hard, the pressure gets transmitted through the jelly part of your eye to your retina. **This is not a good thing to do.** Putting pressure on your eyes like this puts stress on your retina. There's a small chance that you could tear your retina. That could cause partial or even permanent blindness. If you must rub your eyes, do so gently. Or better yet, use eye drops if your eyes are irritated. *Source: I have torn retinas, so I have learned a bit about this subject.*"], "text_urls": [[]], "score": [15]}}, {"q_id": "5zaebl", "category": "Repost", "title": "Why do cigarettes contain so many toxic chemicals?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dewnslq", "dewzmca"], "text": ["Burning any plant matter produces a bunch of toxins. Cigarette tobacco is different in that tobacco companies use chemicals to cure the tobacco, and add other chemicals for different purposes such as changing the flavor, the rate of burn, etc.", "Some of the chemicals you inhale are just part of the plant and the result of chemical reactions as the leaf dries and chemical reactions that occur when the leaves are burned in a cigarette. Those chemicals are bad enough, but then there is the whole assortment of other chemicals added during the manufacturing process that add another level of danger or uncertainty. [List of additives]( URL_0 ) Not all of those additives are in every cigarette. Many are added as flavorings or fragrances and many of them are used in other consumer items like perfumes and food products and many occur naturally. You've probably eaten one or more of these compounds today. Some of the compounds are preservatives to help increase the shelf life of cigarettes. Others have multiple uses. For example, ammonia is commonly added and may act as an anti-microbial during process, but it also acts to \"freebase\" the nicotine, meaning that it chemically alters the nicotine so that our bodies can absorb more of it (and increase how addictive it is). Like I said, many of these compounds are used or consumed on a daily basis from natural or man-made sources with little to no negative effects. The problem is when you mix them all together, burn them, and then inhale them into the lungs that things get dicey."], "text_urls": [[], ["https://en.wikipedia.org/wiki/List_of_additives_in_cigarettes"]], "score": [6, 3]}}, {"q_id": "5zav0p", "category": "Repost", "title": "what do the two numbers on engine oil mean? Such as 5w 20 and 10w 40", "title_urls": {"url": []}, "selftext": "Also, is it okay to put higher weight oil in a car during the summer?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dewo3ev"], "text": ["Previous reply was pretty close. \"W\" is often referred to as winter or more specifically cold, this is the viscosity of the oil when it is cold. The 2nd number is the operational viscosity, or how well it flows once heated. It's is best to put the recommended oil weight in a car. Truth be told there is a complex science to the correct oil ratios. And oil that is too thick may not be able to efficiently move thru oil lines or one that is too thin may not properly lubricant the cylinder walls. In my experience as long as the 2nd digit is the same you should be fine in summer, but the correct weight will always be the safest bet."], "text_urls": [[]], "score": [4]}}, {"q_id": "5zbakg", "category": "Repost", "title": "If energy cannot be created or destroyed, where did all the energy from the Big Bang come from, and where will all the energy go when the Universe collapses?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dewqjby"], "text": ["As far as I know, all that energy was contained within the singularity that all things once were before the big bang. As for \"the big collapse\", it's still not certain that there ever will be a big collapse, as the universe keeps expanding beyond what previous models of the universe originally theorized. Basically, if their theories were completely correct, the expansion should be slowing down, however is is actually speeding up, which means there is some form of energy that is increasing the rate of expansion. So, where will all that energy go? Outward, inward, up, and down. It appears that more and more energy is appearing out of nowhere, which is why scientists are theorizing \"dark energy\", a form of energy that we don't yet know how to observe directly. The only reason they think it exists is because of the expansion of the universe which would be impossible without some unknown force at work. I don't think a 5 year old would understand this, but I don't know how else to explain it."], "text_urls": [[]], "score": [3]}}, {"q_id": "5zd8dg", "category": "Repost", "title": "How are clubs and other social gathering places allowed to have \"Ladies Night\" without people pulling out the discrimination card?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dex5dnr", "dex5ja4"], "text": ["People can pull out whatever cards they want. It's a free country. They generally don't, because it also benefits guys in that it brings more women to bars - men often go to bars to meet women or at the very least enjoy their presence. Having a Men's Night with discounted drinks for men would mean they're paying less for drinks but it would also exacerbate the existing issues with too many men and not enough women at 99% of bars.", "In general it is because 'ladies night' benefits both groups. Yes, men don't receive the monetary discount that women do, but they gain the benefit of there being more women in the club/at social gathering that would not otherwise be there. Therefore no one complains."], "text_urls": [[], []], "score": [8, 3]}}, {"q_id": "5zecg4", "category": "Repost", "title": "Why can we put plates in the microwave but not things like silverware?", "title_urls": {"url": []}, "selftext": "I know there are microwaveable plates and such but I want to understand why and how something is not okay to out in the microwave.", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dexeon8"], "text": ["Microwaves are essentially high-powered radio waves, so think about how your radio works -- you have a long, pointy metal part that sticks up from your radio that \"soaks up\" radio waves from the air, and turn it into electrical flow that, in your radio, gets turned into sound. Those long, straight forks and spoons you put into the microwave will do the same: soak up the radio waves and turn it into an electrical charge. Unfortunately, they're relatively large, compared to the interior of the microwave, and the microwave is beaming 500 - 1000 watts of energy into the enclosure. All those watts start building up on the silverware, but unlike the food, the silverware isn't getting hot -- it's building up an electrical charge. That charge is going to arc to ground when it builds up a whole lot of energy; that spark will jump off the pointy end of your utensil to something and cause a bunch of damage at the points it touches. You'll note that microwaves are, well, made of metal, and some microwaves even have a metal rack or thermometer that can go inside; those are there because they are designed for microwaves; your fork is an unexpected thing that hasn't been designed around, so it's going to throw things off."], "text_urls": [[]], "score": [5]}}, {"q_id": "5zegyw", "category": "Repost", "title": "What's the minimum number of people that need to survive so that when they reproduce, it doesn't become an inbred gene pool?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dexfm6y", "dexfzvo", "dexg16b", "dexsqa6"], "text": ["This is called the [Minimum Viable Population]( URL_0 ) According to [NewScientist]( URL_1 ) it's been calculated to 160 (unrelated) people for a space trip of 200 years, but there's no hard number for humans.", "You need to define exactly what you mean by \"survive\". If you wanted to keep them in a zoo where they get all the food and shelter and medical care they need, there is a decent chance they could survive indefinitely, despite severe genetic problems. If you need them to colonize an alien and inhospitable world, a few hundred might not be enough.", "Since this is one of the things we're going to have to do to get to other solar systems, there's been a lot of studies. But the number is a lot smaller than you might think. [160 is just one study I dug up.]( URL_0 ) Look up \"minimum viable population\". It depends on what you want the population for - if the goal is to get there and back in just a generation or two, you need fewer. If its to plant a thriving population that will survive 40-50 generations you need more. Incidentally, I just finished Aurora by Kim Stanley Robinson which is exactly about this problem. Her population was 2,000 or so.", "Lower than you might think. But you'll need some harsh eugenics laws to maintain it below about 5000 people. Some Aboriginal Australians managed to create long term groups with low population values (low hundreds total, amongst several small isolated groups.) by using strict marriage laws to prevent unintentional inbreeding. basically, you are assigned a surname based on who your parents surnames are, and you are only allowed to marry a person with a specific other surname (usually one that isn't either of your parents or her parents.) This seems to have been stable over multiple thousands of years."], "text_urls": [["https://en.wikipedia.org/wiki/Minimum_viable_population", "https://www.newscientist.com/article/dn1936-magic-number-for-space-pioneers-calculated#.VBiC_XtDLwo"], [], ["https://www.newscientist.com/article/dn1936-magic-number-for-space-pioneers-calculated#.VBiC_XtDLwo"], []], "score": [19, 6, 5, 3]}}, {"q_id": "5zepsd", "category": "Repost", "title": "How are we able to make boats that weigh thousands of tons float?", "title_urls": {"url": []}, "selftext": "I remember reading somewhere once that some aircraft carriers weigh over 100,000 pounds and I imagine most military vessels weigh thousands and thousands of pounds so how are we able to make things\u200b that heavy float? Edit: I meant to say thousands of pounds in the title not tons", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dexhra1", "dexhtsd"], "text": ["As long as the water displaced by the hull weighs more than the boat does, the boat will float. Just look up Archimedes' Principle (of bouyancy).", "The largest US aircraft carriers weigh in excess of 100,000 **tons.** They float on top of the water because the amount of water they displace (the area of their hull which is underwater) weighs exactly the same amount as their entire structure. Water is **heavy** and it doesn't care if the weight sitting within it is caused by water or steel, it behaves the same."], "text_urls": [[], []], "score": [7, 5]}}, {"q_id": "5zfyua", "category": "Repost", "title": "Why do grocery stores use huge rows of open refrigerators without doors, while some refrigeration units at the very same grocery store will have doors which would presumably be much more energy efficient?", "title_urls": {"url": []}, "selftext": "It turns the whole side of the store into an igloo; making customers cold and uncomfortable would seem to not be a good idea. Or does the laziness of not having to open a door to get to your food product win out over the coldness and huge energy costs? No one has a door-less refrigerator at their house", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dext0r2", "dexst3o", "dexsqig", "deycjcz"], "text": ["The energy costs on an open cold case are not as high as you might imagine. It's very different from simply leaving the door open on your refrigerator. Open cold cases are equipped with air curtains, which are sets of narrow vents that blow cold air from the top of the case into corresponding vents at the bottom of the cases (which draw that air in). This effectively forms a \"curtain\" that helps prevent the cold air inside the case from mixing with the warmer air outside. Cases that are heavily shopped and require frequent re-stocking (many times per day), such as produce and meat cases, are less likely to have doors because this reduces the time needed for employees to work the product, which saves money on labor, and it also makes it easier for customers shop, which invites more sales. These items are also much less perishable and able to withstand greater temperature fluctuations than frozen products like ice cream, which you will never find without doors. Side note: the retailer I work for once experimented with doors on all of our wall coolers, including meat and produce, for a little more than a year, not to save money directly, but to collect some kind of energy-efficiency tax credits. Those same doors came off just as soon as those tax credits expired (or so I was told).", "The counter height open top ones are surprisingly efficient. In the modern stores, the only ones with doors are frozen foods and easily spoiled like milk. And yes - not having to open a door makes folks much more likely to just buy it. The energy costs just aren't that huge.", "Most items in the open refrigerated section are things that need to be cold but not necessarily frozen. Like you said, it's easier to see and grab items when there isn't a door in your way. The items in the freezer section (ones with big glass doors) are things that, you guessed it, need to be frozen so they are needed. At night when supermarkets are closed, they actually drape plastic or something similar over the refrigerated section to save energy.", "Everything everyone said about them being surprisingly efficient is true. They can actually be more efficient then ones with doors. Depending on how often or how long they'll be opened. On a meat case where there's always someone looking through the steaks to find the right one the doors would always be open. Or very heavily shopped sections the doors would always be open. The milk and eggs are often in fidges with doors because there's a whole walking fridge behind the display where the back up is kept, and the restocking is done."], "text_urls": [[], [], [], []], "score": [92, 11, 7, 3]}}, {"q_id": "5ziryl", "category": "Repost", "title": "How does the internet work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["deyezvk"], "text": ["I've been recently making a timeline of computer history. Let me make a short summary of the Internet for you: - 1969: ARPANET network was established - It was the first network that was based on the idea of packet switching. Before this, communication between computers was based on establishing a \"circuit\" between A and B. The idea of packets was that anyone could talk to anyone by fragmenting their messages into small amounts of data - packets - that would be sent into a highly interconnected network, the packets would find their way (thanks to addressing) to their destination where they would be joined again to form the message. EDIT: in the beginning the ARPANET consisted of several interconnected computers at different universities, later more and more institutes joined in. - 29.10.1969: First transmission over ARPANET happened - a letter \"L\" was send over a network that would become the Internet. - 1974: A protocol named TCP was \"invented/suggested\" in a document called RFC 675, to replace the NPC protocol that was being used until then in the ARPANET. The document was also already using the word \"Internet\" at this time. TCP protocol would become one of the foundations of the Internet - it specifies how computers should talk to each other in a network based on packets. - 1983: Paul Mockapetri invents DNS - a system that allows translation between computer (IP) addresses and human friendly addresses - domains (such as URL_1 ). - 1990: Tim Berners-Lee invents technology for WWW at CERN. Note that until now the Internet allowed computers to communicate, but there was no world-wide-web of web pages as we know it today. He made these things: - HTTP procotol: a protocol (set of rules for communication) to request and send websites. - HTML language: a language to create websites. - 1st web browser named WorldWideWeb - [1st website]( URL_0 ) - 1994: Tim Berners-Lee founds W3 consortium to make standards for the Internet, such as new versions of the protocols he made. - 1996: Internet grows bigger and is running out of addresses! As a result, IPv6 protocol is being developed to provide more addresses and features. - 1996: Google starts as a research project by Larry Page and Sergey Brin. - 1996: W3 releases the first CSS standard - this allows webpages to look \"prettier\". - 2001: Wikipedia starts. - 2003: 4chan starts, anonymous start to form on the website. - 2003: Mark Zuckenberk writes Facemash, to later become Facebook. - 2005: reddit starts. - 2006: Twitter starts, 1st tweet sent. - 2006: Facebook launches publicly. - 2011: Last IPv4 address was given out. EDIT: but don't worry, we've got IPv6 widely supported now, so we've got more addresses to use"], "text_urls": [["http://info.cern.ch/hypertext/WWW/TheProject.html", "www.example.com"]], "score": [13]}}, {"q_id": "5zj0mb", "category": "Repost", "title": "How can some food / diet drinks have 0 calories?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["deyflyo"], "text": ["The drinks are usually just flavored water with artificial sweeteners like acesulfame-k that pass right through the body. The konjac pasta is a type of fibre that is not absorbed by the body. It fills up your stomach though so makes you feel full. People who are trying to lose weight should probably not eat them, and instead lots of green beans and other water\\fibre rich vegetables which do the same thing but also provide vital nutrients."], "text_urls": [[]], "score": [4]}}, {"q_id": "5zjv3m", "category": "Repost", "title": "How does sound travel through a phone?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["deymulh", "deymwd4"], "text": ["In essence it doesn't. Sound is converted into an electric signal by a microphone which then travels to the destination where it's converted back into sound by a speaker.", "The phone has a microphone and a speaker. The microphone picks up the sound waves and translate them into an electric signal. The electric signal travels through the phone lines (or in the case of cell phones, gets translated into a radio signal and sent through the air), and the phone on the other end receives the electrical signal, then use them to activate the speaker in the phone, generating soundwaves that are roughly the same as what entered the microphone on the other end."], "text_urls": [[], []], "score": [3, 3]}}, {"q_id": "5zjzhu", "category": "Repost", "title": "Why does most articles in the internet tend to be cut by a 'Continue Reading' button?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["deynly4", "deyo2qv", "deyrw4p", "deysc5x"], "text": ["Knowing that the person is actually reading the page allows higher advertising rates to be charged. I mean, if you were an advertiser, wouldn't you pay more for a page that had proof that it was being read over a page that didn't?", "What the other guy said was true, and they'll also \"double dip\" on ads sometimes. Hitting the continue button may load another blob of ads between the article chunks, or may cause the ads on the page to refresh and change. This lets them sneak in a couple more ad views.", "They divide an article in several pages so you have to click to see the next page and more ads appear, increasing the chances of someone clicking an add or showing ads more times. This happens because advertisers pay per click or per number of times an ad appears.", "Put it all on one page, you only show the user one page worth of ads. Put it on 10 different pages, you get 10 times as many ads. Also, subscription-only sites (newspapers are notorious for this). They let you read the first part of an article, then once you've made your way into the content and want to learn more, you're presented with a \"Click here to continue reading\" that takes you to a page that informs you that you need to be a paid subscriber to continue reading."], "text_urls": [[], [], [], []], "score": [23, 14, 5, 3]}}, {"q_id": "5zka75", "category": "Repost", "title": "Why can't an electric car power itself?", "title_urls": {"url": []}, "selftext": "Couldn't you create a system that uses the circular motion of the wheels to crank a generator/alternator to create electricity to recharge a battery?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["deyq0qp", "deyr3ud", "deytggi"], "text": ["No, because taking energy away from the wheels as they're turning will make the car slow down. You can never get back the same amount of energy you put in and still have the car move forward. What you can do is charge the battery a bit when you *want* to slow down. Electric cars can do that, but it cannot ever be enough to actually recharge the battery entirely. You just get a little bit of energy back.", "One of the fundamental laws of the universe is that you can never get more energy back than what you put into something. The total amount of the energy in the universe is constant--you can't make energy from nothing! Another important factor is that no machine we can make is going to be 100% efficient. This means that some of the energy we put into a system is going to get \"wasted\", meaning that it becomes a form of energy that doesn't do the kind of work we want it to. This is usually heat in a system such as an engine. In electronics, for example, some of the electricity traveling through a wire turns into heat and heats up the wire, meaning you will always lose some energy along the trip. Let's look at this in terms of an electric car. I don't know much about the details of how an electric car engine works, but you can imagine there are lots of places where the electrical or mechanical energy gets turned into waste heat--think of electric wires heating up, or the friction of a drive shaft on its bearings heating them both up and taking some of the rotational energy away. Therefore, the energy that is put out by turning the wheels is always a little bit less than the energy you \"pull out\" of the battery. So, in order to charge the battery, what would you have to do? You'd have to have **extra** energy in the wheels compared to the energy you put into the engine, which is impossible because of the first part up above--you can't make energy out of nothing! You could conceivably hook up a system so that half of the energy going to the wheels goes to recharge the battery, but that's kind of silly, since you would then need to pump out twice as much energy out of the battery to make the wheels spin at the same rate--so it works out to be the same. What about charging with solar panels? Well, now you've added another source of energy--the sun! We're no longer just powering the car off the energy stored in the battery; we're also using the gigantic fusion explosion happening constantly 93 million miles over our heads! Clearly, there's enough energy there. The problem is converting it to electricity fast enough and efficiently enough to power the wheels or recharge the battery in any sort of useful way. I don't know the mathematical details, but somebody on reddit recently did the math and I believe it would take a couple of days to charge the battery of a Tesla with the most efficient solar panels we have if they covered the car. You then have to take into account that solar panels are heavy, and they might make the car less efficient to move in general.", "This is a perpetual motion machine. They are impossible as they violate the second law of thermodynamics, in that you cannot get out more energy than is put in. No machine is perfect, there will always be losses in the form of heat and motion. If a motor were to drive a generator, the losses come in the form of heat due to electrical resistance and bearing friction, and eddy currents opposing rotation of both the motor and the generator. So all a car can do is try to minimize loss by reducing aerodynamic and rolling resistance, recapture inefficiency through regenerative breaking and coasting, and utilize free energy in the form of solar (though right now no production vehicle has solar panels on the sun bearing surfaces because they're not yet that cost effective, you only see this in solar racers, and those \"cars\" are made of balsa wood and weigh 300kg or less)."], "text_urls": [[], [], []], "score": [16, 14, 6]}}, {"q_id": "5zlb59", "category": "Repost", "title": "Why do we cry when we're sad?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["deyyvuw"], "text": ["We also cry when we're happy. It's because there's not enough room to keep all the feels inside, and so they spill over. Now flair your post or you'll cry when it's deleted."], "text_urls": [[]], "score": [4]}}, {"q_id": "5zlh3m", "category": "Repost", "title": "how does the Higgs boson give things mass?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dez5nfr"], "text": ["The vast majority of the mass in the universe is not due to the Higgs boson. It's actually due to the energy of the strong force. But to answer your question, I'm going to have to go to take a small detour to special relativity and light. Light doesn't have mass, but it does carry momentum and does have energy. Because it has momentum, when a photon \"bounces\" off a reflective surface, it imparts momentum to that surface. This is the way [solar sails]( URL_1 ) work: light from the sun reflects off the surface of the sail and imparts momentum to the sail and spacecraft. OK, so what would happen if you build an extremely lightweight box with perfectly reflecting walls and stick a whole bunch of light inside? If you run through the math, it turns out the box will act just like it has mass corresponding to the energy of all the light inside. It acts in every way like it has mass: you can accelerate the box; you can decelerate the box; the box will be attracted to massive bodies (in general relativity, massive bodies bend the path of light); and so forth. This is the [mass-energy equivalence principle]( URL_0 ). OK, so energy and mass are equivalent. With the strong force, we have something similar to the light box: the strong force creates a \"box\" (a neutron or proton) about which quarks and gluons can exist. Most of the energy in the neutron or proton is actually in the strong field. Very little of it is the mass of the quarks. Since most mass in the visible universe is due to nucleons, most of the mass of the universe is actually the energy of the strong force. So now, we get back to the idea of the Higgs boson. How does it give mass to quarks, electrons, and neutrinos? The theory is very complex, but it basically boils down to the same sort of thing. The Higgs field generates a \"higgs box\" around those fundamental particles where the particles interact with the Higgs field. There is energy associated with this and the result is again that the particles act like they have mass -- they can accelerate, be attracted by massive bodies, etc.... Since they act like they have mass in every way, we just say they do have mass. And I can hear the inevitable question coming: why to photons again have zero mass? They have energy right, so why doesn't the mass-equivalence principle apply to them? So a photon by itself doesn't have mass because it travels at the speed of light. There is no accelerating it. It always just travels at the cosmic speed limit (the speed of light). Once you put a \"box\" around the photon and *force it to interact*, the box gains mass equal to the mass of the photon. Mass then is the ability to accelerate and is a measure about how difficult it is to accelerate things."], "text_urls": [["https://en.wikipedia.org/wiki/Mass%E2%80%93energy_equivalence", "https://en.wikipedia.org/wiki/Solar_sail"]], "score": [25]}}, {"q_id": "5zlk7x", "category": "Repost", "title": "Why are some companies not profitable, with no proven route to profitability, worth billions of dollars?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dez1bo5", "dez1jrq", "dez4zrw", "dez3zfb"], "text": ["Welcome to the world of investing. One unwritten rule is that if enough people believe something is true, it will be true. It's gambling really. These companies live off marketing, dreams and the pockets of people who hope to strike it rich. If you can generate enough buzz and hype it can become self fulfilling because people will buy the stock, thus creating the very value the company balance sheet lacks.", "Either investors think there will be a path to profitability once a critical mass of customers is achieved, or there are investors who think the company's technology/customer base/business model/etc is a likely acquisition target.", "You're assuming that there is a \"rational\" relationship between profit and valuation. Rational means different things to different people. A stock is worth nothing more than what someone's willing to pay for it RIGHT NOW. What people are willing to pay for a stock is often correlated with things like profit, growth potential, etc. Don't get confused with correlation and causation. The cause of a stock YOU perceive to be worthless being bought at $100/share? Someone was willing to pay $100 for it. The rest is correlation. And some variables (profit, growth potential) correlate much better than others (news article hype, buyout rumors, product leaks). Successful investors make their millions finding opportunities where the perceived value is either too low or too high based on many of the indicators I just mentioned.", "Those companies are not worth billions of dollars. A company with no proven route to profitability is very likely going to end up being traded as a penny stock if it goes public. Take, All American Pet Company - actually makes products and sells them, but not profitable and not worth billions of dollars. If you are talking things like Tesla - where the company is worth billions despite making a \"profit\" - you need to understand the numbers and what constitutes \"profit.\" Tesla earns quite a lot of revenue actually. But the thing is that it is a fairly new company with lots of costs, and it is a tech company, so lots of research. If you solely looked at money in for goods sold, costs out for labor and cost of goods sold - Tesla is \"profitable.\" However, it then turns around and reinvest millions into research so it can stay ahead of the curve and invent new batteries, etc. Investors look at the numbers and figure out that by xyz they will have all the infrastructure in place will have all the tech needed, and will be making cash hand over fist and eventually pay out dividends."], "text_urls": [[], [], [], []], "score": [6, 4, 3, 3]}}, {"q_id": "5zlkfo", "category": "Repost", "title": "How are potholes created on an otherwise consistent surface?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dez1c6d"], "text": ["Roads aren't consistent surfaces; they are porous and water can seep through asphalt. Water will soften the soil beneath the road. When it gets cold, water trapped under the road expands and pushes the asphalt upwards. When the water thaws, there is now a gap in the pavement where the ice used to be and the softened soil; frequent traffic will break the asphalt apart and erode a hole into the road."], "text_urls": [[]], "score": [4]}}, {"q_id": "5zmb5p", "category": "Repost", "title": "Imaginary Time", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dez9z3t"], "text": ["[Wikipedia sums it up pretty well]( URL_0 ): > If we imagine \"regular time\" as a horizontal line running between \"past\" in one direction and \"future\" in the other, then imaginary time would run perpendicular to this line as the imaginary numbers run perpendicular to the real numbers in the complex plane. Imaginary time is not imaginary in the sense that it is unreal or made-up \u2014 it simply runs in a direction different from the type of time we experience. In essence, imaginary time is a way of looking at the time dimension as if it were a dimension of space: you can move forward and backward along imaginary time, just like you can move right and left in space. > > The concept is useful in cosmology because it can help to smooth out gravitational singularities in models of the universe, where known physical laws do not apply. The Big Bang, for example, appears as a singularity in \"regular time.\" But, when visualized with imaginary time, the singularity is removed and the Big Bang functions like any other point in spacetime. We don't have evidence of its existence. Today, it is still just an idea that helps deal with certain mathematical problems we encounter in physics. Whether it's the correct solution to those problems or not is not yet known."], "text_urls": [["https://en.wikipedia.org/wiki/Imaginary_time"]], "score": [3]}}, {"q_id": "5zmn9o", "category": "Repost", "title": "How does a 2-in-1 shampoo and conditioner work", "title_urls": {"url": []}, "selftext": "I always thought that shampoo removes some oils and conditioner adds others, so how do these opposite effects get combined into one bottle?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dezcqw1"], "text": ["Not very well, is the short answer. Cosmetics companies did find conditioning chemicals that stay on the hair when used in a 2-in-1, possibly they're more resistant to the cleaning chemicals than natural oils. But they're still not able to match what a separate shampoo and conditioner can do, and product buildup in your hair can be a problem. On the other hand it's usually better than shampoo alone. Of course there are plenty of people who swear by conditioner-only, water-only, and even no hairwashing at all. Do whatever seems to work for your own hair."], "text_urls": [[]], "score": [5]}}, {"q_id": "5zmq3h", "category": "Repost", "title": "how artists make money through apps like Spotify or iTunes?", "title_urls": {"url": []}, "selftext": "I have Spotify Premium because I like to think I'm contributing to the artists I listen to. But how exactly does that work? Do the musicians receive so much money each time a song of theirs is downloaded? I really don't know the first thing about this so I was hoping someone could enlighten me.", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dezc7rd", "dezmki5"], "text": ["As fas as I know, you as an artist get money from Spotify depending on the percentile over the total plays of any song in Spotify that your creations represent. Or something like that. I've got friends with small groups that have their music on Spotify and they get paid peanuts, if anything.", "Cool story about a band making $20 grand from spotify. The band wanted to raise money to go on a new tour so they released a record that was nothing but silence and asked their fans to stream it while they were sleeping. lol they made 20k for literally nothing. URL_0"], "text_urls": [[], ["http://www.theverge.com/2014/5/7/5690590/spotify-removes-silent-album-that-earned-indie-band-20000"]], "score": [6, 5]}}, {"q_id": "5zndsm", "category": "Repost", "title": "Whats the difference between 32Bit and 64Bit machines?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dezryxf", "dezjfhc", "dezue6l"], "text": ["For a true ELI5 answer let me try this. It's an incredibly simplistic explanation, but I think it might help. Imagine that you can only count with your fingers. You can only count to 10 before you have to write down your current answer and then keep counting on your fingers until you get to the number you want. So to count to five you just count five fingers. To count to 10 you count all 10 fingers. To count to 15, you first count to 10 and write that down. Then you count to 5 and write that down. Then you add those two numbers together and you get 15. If you had 20 fingers, you could count to 15 all at once and be done. A 32 bit computer has 4,294,967,296 fingers. a 64 bit computer has 18,446,744,073,709,551,616 fingers", "A 32 bit machine means that it can handle individual things that are up to 32 bits long. That means it can add, subtract, and copy 32 bit numbers. It also means that it can use 32 bit numbers as a addresses. because there are 2^32 (4,294,967,296) possible values that a 32 number can hold, and each byte of memory needs its own unique address, it can only address 4,294,967,296 bytes, which is 4 GB. So even if you have more than 4 GB of RAM, a 32-bit machine can only use 4 GB of RAM because it doesn't handle numbers big enough to address more than that. A 64 bit system, on the other hand, could theoretically address as many as 2^64 (or 18,446,744,073,709,551,616) bytes (or 4,294,967,296 GB). The same goes for 32 bit programs (even if they're running on a 64 bit machine). There are less significant benefits to a 64 bit machine vs 32 bit. If you need to add two 64 bit numbers on a 32 bit machine, the programmer has to split each number into two different numbers, and add the less significant half as well as the most significant half. That's like breaking 25 into 2 and 5 and breaking 46 into 4 and 6, then adding 5 and 6 and storing the result (1), with incrementing the 2 in 26 (because you need to carry), then adding the ten's column. A 64 bit machine could do this in just one instruction, while adding a 64 bit number broken into 32 bit numbers would take at least two instructions. However , most programs don't need to use 64 bit numbers. Also, the 64 bit version of the CPUs the run on PCs have twice as many registers (16 vs 8). Registers are fast places to store numbers on the CPU so that they can be immediately available to do something. If your software is 64 bit, then it can use those extra registers instead of wasting time going to RAM. A 32 bit program can't make that assumption, because those registers weren't there before 64 bit versions of PC CPUs were made.", "To oversimplify things: The difference is mostly in how much memory they can use. Computers use memory (RAM) to work it is an important part of their \"brains\". The CPU is what they use to \"think\" and the RAM is where they hold their \"thoughts\" (and short term memory) while doing so. The amount of memory a computer has limits the size of things they can think about. If stuff gets to big for their memory they have to do tricks like writing things down like when you have to write down long division on paper when you can't do it in your head. This writing things down (on the disk) takes a really long time compared to just doing the calculations in your head so things start to become really slow if you have to deal with things that don't fir into your memory whole. Some things that are too big for your memory can't even be really worked with even if you use all sorts of tricks. So having a large memory that can hold lots of ideas at once helps a computer. Because a computer's memory works different from a human one the limits of how much you can put into it are much more fixed. Each piece of information you put into the memory needs to have an address of where you put it. You can think of it like a sheet of graph paper with all these boxes predawn on it and each box fits exactly one number or letter. The more boxes there are the more information you can write on the paper. The way a computer works is by numbering those boxes and then specifying that the number it ones is for example in the 137th box. The problem here is that if you number the boxes you end up with some pretty large numbers like box 1,048,576. That information about where the information is needs to be written in boxes itself. Writing out numbers in the millions would take 7 boxes in normal human writing. If you only left six boxes of room to write down the number you can only address the first 999,999 boxes and any additional paper you may have with empty boxes that is leftover is useless to you. Computers don't write things down in number like 1, 2, 3, 4, 5, 6, 7, 8, 9, and 0 but just use two numbers 1 and 0. (we call that binary) One binary digit (usually called bit) can be either a 1 or a 0. Where a normal two digit number can have 100 different values (00-99) and two binary digit number (2-bit number) has only 4 different values (00, 01, 10 and 11). If you use 8 bits you can have 256 different values we usually call these 8-bit numbers a byte. Computer systems using 2 bytes or 16-bits can use them to make 65,536 values. Computer systems using 4 bytes or 32-bits can use them to make 4,294,967,296 values. Computer systems using 8 bytes or 64-bits can use them to make 18,446,744,073,709,551,616 values. When I bought my first computer it had 64 thousand byte of memory which was sufficient at the time. Later computers used different architectures which allowed them to address much more memory than that. Up until a few years ago using 4 bytes to address where in the memory something was stored was sufficient. after all you had over 4 billion places to store things. This worked out to a storage space of 4 Gigabyte. Nowadays it is common to use more than 4GB of memory even in home computers. To take advantage of that you need both hardware that can work with 64bit addresses and software which can do that too. Vendors like Intel and AMD started making CPUs which could do 64-bit and operating systems like Windows started coming out some time ago. Nowadays 64-bit has become the standard for most normal computers."], "text_urls": [[], [], []], "score": [105, 5, 4]}}, {"q_id": "5znmcq", "category": "Repost", "title": "Why do people tilt their heads while they're writing?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dezkrhs"], "text": ["That was explained a couple of years ago [here]( URL_0 )"], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/2a2fqo/eli5_why_do_i_tilt_my_head_the_the_left_when_i/"]], "score": [6]}}, {"q_id": "5znvf0", "category": "Repost", "title": "Why is it that unplugging the WiFi router can fix the problem with slow internet, and what happens to cause it to becomes slower than it should be?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dezm22e"], "text": ["The router has something called a translation table. It's a list of all connections currently going on. When a computer using the router wants to connect to something on the internet, the router writes it down in the translation table so that when a response arrives the router knows what to do with it and to which computer to send it. The router is supposed to know when connections end and remove them from the table, but like all programs, router software can have bugs, and sometimes those bugs cause connections to stay in the table forever. Eventually, the table fills up, and when your computer tries to make a new connection, it fails because the router has nowhere to write it down. This makes your internet work erratically, because most of the time it won't work, but sometimes some space in the table frees up and briefly you can make connections again. Restarting the router empties the table and solves the problem until it fills up again. There are some other possible reasons for this - maybe the router's software crashed, or there is a problem with the connection between it and the internet that will be solved by starting it from scratch - but I think this is the most likely, and the others are too specific to know about or explain anyway."], "text_urls": [[]], "score": [5]}}, {"q_id": "5zo86d", "category": "Repost", "title": "How did colors end up with their associations? (Pink/Purple being \"girly\", Blue for boys, Green with envy). Where did it start?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dezos5m", "dezpn1i"], "text": ["Depends on culture. Romans used purple to signify royalty. Indians view pink as lucky and it is worn by both sexes. Different colors mean different things to different cultures. They aren't universally symbolic generally. As to the specific origin of the symbols you're asking about: I dont know. I'll leave that to someone else.", "Purple used to be the most expensive dye, being produced from shellfish in the city of Tyre; as it was so expensive only the top could afford it, so it became the colour of Nobility"], "text_urls": [[], []], "score": [18, 11]}}, {"q_id": "5zox0i", "category": "Repost", "title": "why are photos rectangular when camera lenses are circular ?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dezuph9"], "text": ["Because lenses don't capture photos, sensors and film do. The sensor and film are rectangular. Lenses just focus light. You can even make[a camera without a lens]( URL_0 )."], "text_urls": [["https://en.wikipedia.org/wiki/Pinhole_camera"]], "score": [8]}}, {"q_id": "5zql3z", "category": "Repost", "title": "Why are the really old black and white videos almost always sped up?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["df07xn3"], "text": ["Actually, time was faster about a hundred years ago. That's why life expectancy was shorter and smoking was healthy."], "text_urls": [[]], "score": [4]}}, {"q_id": "5zqmix", "category": "Repost", "title": "How does medication that targets specific areas of the body (such as back/head/sinuses) work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["df06i8j", "df06onj"], "text": ["Well it doesn't. Medicine, specifically pills are ingested and spread throughout the body through blood once it hits the liver. It then travels through the whole body and provides relief in problem areas but can also provide side effects in other areas. Thats why there is usually a long list of side effects becauce while it may fix your issue it can create another else where be it minor or major. One pill can reduce headaches but could also cause dry mouth. Sometimes we use medicine for their side effects. There is an anti inflammatory I used to take because one of the side effects were less sweating, I have hyperhidrosis which causes extra sweating of the palms. So while I didnt need the anti-inflammatory effects, the side effects were useful.", "It doesn't. You notice a change where you have pain and not where you don't have pain. Just like a \u00a35/$5 box of paracetamol (tylenol) works no better than a 16p box. Source: I'm a doctor."], "text_urls": [[], []], "score": [4, 3]}}, {"q_id": "5zt880", "category": "Repost", "title": "Why do words we've known our whole lives occasionally look and sound really awkward to us?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["df10nuj", "df0ucju"], "text": ["It's actually a psychological phenomena called Jamais Vu, the opposite of Deja vu, and it's the process of something recognizable becoming unfamiliar with repeated use, such as if you say one word over and over, it will eventually just become sounds to your brain and lose its meaning.", "Not sure if I'm right but you might be experiencing [semantic satiation]( URL_0 ). If you pay attention to a certain word (such as \"bath\") and repeat it numerous times, your brain starts getting \"tired\" of it and starts thinking it's just \"random nonsensical sounds\" for some time."], "text_urls": [[], ["https://en.wikipedia.org/wiki/Semantic_satiation"]], "score": [8, 4]}}, {"q_id": "5zth0g", "category": "Repost", "title": "Third-Wave Feminism", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["df0xo5t"], "text": ["The various \"waves\" of feminism refer generally to mainstream feminist movements in Western countries (US/UK, primariily). First-wave feminism focused on basic rights (1800 - 1950s) like voting and property ownership. Second-wave feminism (1960s - 1980s) broadened out to more social rights that were of concern to middle-class women -- reproductive rights, sexual freedom, hiring, domestic violence, etc. Third-wave feminism (1990s - present) broadens out what \"feminist issues\" include, as it starts to include more issues that are of interest outside the world-view of white, middle-class, heterosexual women. LGBTQ and racial issues become more central, and the question of \"intersectionality\" becomes key. Intersectionality says that any individual woman is an intersection of many different cultural identities -- she's not just a woman, she's also from a particular culture, has a particular sexuality, raised in a particular religious tradition, and so on, and that all these intersecting identities are all a part of her lived experience. As this is also the first time that trans issues have been included as a part of feminist issues, the question of \"what is a woman\" is raised in this wave for the first time, or at least defining it beyond genital sex at birth; this has led to a questioning of how many sexes there are and whether or not gender even needs to be a definitive category. There are also some who talk about a fourth-wave feminism, though that's a topic of some debate."], "text_urls": [[]], "score": [8]}}, {"q_id": "5ztqo3", "category": "Repost", "title": "Why do we use English names (Spain, Japan, India) for non-English places (Espa\u00f1a, Nippon, Bharat/Hindustan)?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["df0ynw4"], "text": ["Many languages have names for other countries in their own language. It's not racism, it's just familiarity. Example : America in Korean is \ubbf8\uad6d (mi-gook) which means land of rice (meaning wealthy) and then they call Canada \uce74\ub098\ub2e4 which is simply pronounced Canada. It really depends on what language your using, that's all."], "text_urls": [[]], "score": [7]}}, {"q_id": "5zwu7i", "category": "Repost", "title": "How do tattoos work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["df1o2lz"], "text": ["Tattoos work by depositing a small amount of ink into the dermis of the skin, which is your second layer of skin. The needle being used punctures your epidermis somewhere between 50-3000 times a minute. Every time it punctures your epidermis and enters the dermis, it deposits ink. The cells in the dermis are more stable than those in the epidermis, which is why the dermis is used along with visibility reasons. The ink becomes trapped there and is only subject to fading and minor dispersement over time. As for certain colors of ink hurting more, I've personally never heard that and I have several tattoos and have never experienced it. Hopefully someone else can answer it."], "text_urls": [[]], "score": [7]}}, {"q_id": "5zx3ns", "category": "Repost", "title": "What makes up the crust that sometimes forms in our eyes when we wake up?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["df1prc8"], "text": ["rheum. It's dried mucus that has accumulated while you slept, without the normal activity of your blinking eyes to flush it away. It is like runny snot, with some dead skin, dust, and blood cells."], "text_urls": [[]], "score": [5]}}, {"q_id": "5zxxpo", "category": "Repost", "title": "How does this [image of CPU die] make a computer work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["df1x1ui"], "text": ["> I'm talking more on a physical level. Like, what is actually going on with all those gold(?) pads and traces? That is an immensely complex question. Those \"gold pads\" are not gold pads, they are densely packed masses of transistors and memory structures. They are so small that even that magnified view has no hope of showing them as anything other than a slightly iridescent sheen of material. In this case they are 14 nanometers which is roughly half the length of a ribosome, or about twice as thick as a cell membrane. Ultimately how computers operate comes down to the concept of a transistor, or a solid-state electrical switch that conducts or insulates a junction based upon the presence of a current on a third wire. By combining those structures basic mathematic operations can be performed, and the results transferred on to other similar structures. How that all translates into what computers do on a daily basis is far too complex for such a forum."], "text_urls": [[]], "score": [6]}}, {"q_id": "5zy238", "category": "Repost", "title": "Why do we only define all humans as 1 species compared to animals and insects where very slight differences can define a new species", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["df1xf8w"], "text": ["One of the main characteristics of a species is being able to mate and produce fertile offspring."], "text_urls": [[]], "score": [6]}}, {"q_id": "5zy3bl", "category": "Repost", "title": "Why is an elevated heart rate bad for you when it's due to nerves/anxiety but good for you when it comes from exercise/activity?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["df1xmr7", "df1xlx3"], "text": ["Seems more like the anxiety one is a constant thing - your heart pounding away for no reason. While the exercise is limited duration, and more importantly, associated with muscle activity elsewhere - that activity is the healthy part.", "Very much so. The sudden jump in heart rate and strain on the cardiovascular system is what can cause acute myocardial infarction( heart attack) along with stress. The endorphins released during exercise is what is positive for your body along with the gradual rise, and fall, of heart rate."], "text_urls": [[], []], "score": [3, 3]}}, {"q_id": "5zzu03", "category": "Repost", "title": "Why is it that we stretch when we get tired?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["df2ihja"], "text": ["Physical activity stimulates blood flow, including to the brain. Increased blood flow to the brain increases wakefulness. Stretching is basically the \"lowest cost\" way your body has of getting that physical activity, and thus the most instinctive."], "text_urls": [[]], "score": [6]}}, {"q_id": "601mw0", "category": "Repost", "title": "What is fire?", "title_urls": {"url": []}, "selftext": "I think I know fire is gases, but physically what in the heck is fire? You can't physically grab it, but you can certainly feel it. What in the heck is it?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["df2szsi", "df2tbmw", "df2wzx2", "df2v0gi"], "text": ["Fire is the rapid oxidation of the molecules in the fuel source (i.e. logs in a fireplace). It is an exothermic reaction which is where the heat comes from. The energy generated from the oxidation of the atoms excites the electrons in the combustible material. When the excited electrons fall back down to their ground state, they release photons which is the source of the light that you see (i.e. flames).", "Let's say we take a magnifying glass and focus the sun's light on a piece of wood. The focused light \"burns\" the wood. A little bit of white smoke comes off the wood, and a black mark is left on the wood. The black dot is essentially a little black dot of charcoal. The white smoke is volatile and flammable compounds. That white smoke is actually what becomes fire. As those flammable compounds are released from a piece of wood or paper, if they get hot enough, and mix with oxygen from the air, they go through another chemical reaction. They combine with oxygen, turning into carbon dioxide and water, and maybe some other things. This reaction releases a lot of energy, in the form of heat and light. This is what you see as the flame.", "Fire the rapid oxidation with the evolution of heat and light. What happens is the material are heat so much, they turn to a gas which then can be light on fire Fun experiment to do to understand this, but don't fire is super dangerous and you might burn down everything, Take a big cardboard tube (from tinfoil, paper towel, wrapping paper) and light one end. Hold it up straight or diagonally. Be careful!! Use tongs or a glove, it gets hot!! Smoke will start to come out the top, and it may even spontaneously ignite. The smoke is parts of the tube that became a gas and now are burning.", "Fire is a process. It oxidizes a fuel source, releasing hot gas and heat/light."], "text_urls": [[], [], [], []], "score": [73, 15, 6, 5]}}, {"q_id": "601txq", "category": "Repost", "title": "how were languages first translated?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["df2tlwe"], "text": ["You literally have to start somewhere, and the universal understanding of touching or pointing at an object and declaring it is the start of that process."], "text_urls": [[]], "score": [4]}}, {"q_id": "6020fd", "category": "Repost", "title": "How do buffets stay in business?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["df2uz4n", "df2vung", "df2vsbd", "df2zmg0", "df2wpru"], "text": ["because if you buy in bulk it's insanely cheap. sure they might lose money on the one or two big eaters, but everyone else eating salads and cheap filler foods more than make up the difference. with the amount of food going through, buffets can buy cheaper cuts of meat and stuff closer to expiration dates since they're insanely marked down. labor isn't as expensive as you think.", "Typically a buffet will require less wait staff than a regular restraunt which saves some money.", "Much more efficient to make lots of the same thing than jumping from roll to roll, it's a way to use up what's got less life left(ie. they've got a surplus of salmon, put out more salmon rolls and people will eat what's out), for each person that eats a ton there are two who don't eat that much, they make the mark-up on sake or cocktails, etc.", "at a pizza buffet, a person needed to eat 40 slices (they're not too big but that's still thousands of calories) in order for the company to break even", "Some good answers here, but to be holistic, keep in mind that food costs are only a part of a restaurant's business model. For most restaurants, food costs are only 25-35% of total operating expense. Nobody ever eats $15 worth of food costs (although they might waste it. I've seen plenty of that). For a buffet, the volume of people going through helps, but if you average the food consumed, people actually eat a lot less than you might expect. At our pizza/chicken buffet, each guest equates to a third of a pizza for planning what we need to have cooking. The buffet prices tend to be high because there's lot of overhead involved in running a large restaurant (and most buffets are large, particularly the chains. We seat 300.) and the dinner prices encompass all of that. Food cost is only a small portion."], "text_urls": [[], [], [], [], []], "score": [29, 15, 7, 3, 3]}}, {"q_id": "602j30", "category": "Repost", "title": "Why is 24 FPS unplayable in video games, but looks fine to me in movies/TV shows?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["df36353", "df308hv", "df3240s", "df2zl8q", "df3ixir", "df3azzo", "df3akrc", "df31ar7", "df30wwf", "df3c67b"], "text": ["A lot of these responses are correct but are missing a critical point; That is that games require input and interaction while movies and television are passively observed. When a game renders a low amount of frames per second, *especially* when it dips under ~30 FPS, the player can feel the difference much more because it takes more time for input to be read and then displayed on the screen. In other words, this means that every action a player makes in such a scenario feels sluggish and unresponsive because when our brains are expecting to perceive a change much faster than we do. It can cause an element of frustration and it certainly does not help in immersing the player into the game as they are effectively being constantly reminded that something is wrong. Television and movies on the other hand require no input from those watching it so utilizing lower frame rates - so long as they are constant - is far more comfortable than if we were to play a game at the same FPS.", "Film has natural inherent motion blur which smooths things out. When played back, each image is actually flashed two or three times which also helps. Standard definition television was interlaced, so the nominal 25 fps of PAL or 30 of NTSC actually meant new image data being displayed 50 or 60 times a second but only half the image each time. Games displayed on a monitor or modern TV have neither of those things. Additionally a rock-solid 24 fps in a game, with a monitor refresh rate suitably matched, probably wouldn't be so bad. The problems really come when an average 24 fps comes with stutter and lag, and momentary dips well below that, and screen tearing because the monitor refresh rate doesn't match. EDIT: The replies show split opinion on that, which is not too surprising. I think partly it's what you're accustomed to. Console gamers are used to 30 fps and don't mind it, but PC gamers who usually play at 60+ will notice.", "Motion pictures work because of an attribute of our visual processing called persistence of vision. If you are shown a rapid series of still frames that are moved into position quickly (without bluring them which is what a shutter in a movie projector does) then it tricks the eye into seeing motion. 24FPS happens to be on the lower end of the minimum number of frames to fool the eye into seeing motion without causing discomfort however it's not high enough to show all types of motion clearly. There is something called the picket fence effect, where objects panning past a 24fps movie camera, appear to judder or jump past the camera noticeably, making it hard to make out the clear edges of the fence boards. This is why panning shots in movies are generally done slowly and controlled, so the frame rate of the camera isn't over loaded with too much motion. In a video game though it is up to you to control how quickly the camera pans around, and you generally need to look around quickly, which doesn't work so well at 24fps. It might look okay for a cut scene where the game director can slow down the camera so it looks good, but in live play it's not enough. At 30fps, most motion looks acceptable, but panning motions still seem jumpy. At 60fps even panning and strafing shots seem smooth but the eye can still see even more detail all the way out to 100+fps if very fast motion is observed. This is why many gamers prefer 60+fps in games, because most kinds of game motion like spinning the camera around, aiming, jumping, running, all basically look smooth, with higher frame rates having diminishing returns. Ironically when you shoot film at higher FPS, at a certain point it stops looking like film and starts looking more like video like a news or sports broadcast. Movies have a certain look to them that is a combination of the color pallete and dynamic range of the image, but also the lower fixed frame rate which gives movies that 'film' look.", "Movies are static or low-movement shots. Video games are smooth panning with a constantly-moving camera point of view. Low FPS is most noticeable during panning, making video games much more sensitive to bad FPS.", "FWIW, 24 fps looks pretty bad in a lot of common movie scenarios, such as panning across the landscape. In those cases, you can easily see how rough it makes the image.", "Professional game designer here. It really depends a lot on the game. While more fps is always better, it's not always needed. For something that requires twitch based reaction and frame counting, such as fighting games, 60 fps is the minimum acceptable speed. Strategy and casual games usually are a bit more relaxed with 30 fps being fairly acceptable. I haven't worked directly with Sony or Microsoft in recent years, but both used to have a TCR/TRC that stated you game should not fall below 15 fps for any prolonged length of time. Now, \"prolonged length of time\" is fairly subjective, so we always did our best to never fall below 30 fps, but considered it a critical bug if the game ever fell below 15 fps...at least when getting ready for submission (in regular production we didn't care as much). You would be surprised how hard this is to actually accomplish in open world games. Near the end of my first project, we seriously had to pick and choose what bushes/foliage we wanted to leave in and to take out to improve framerate. Foliage is the WORST to deal with. While particle effects can be rough too, foliage is pretty much always around. It usually has to move in the wind, move for the player and be translucent around the edges. Even when we started using professional middleware (speedtree) for our foliage it was still an fps killer. Anyhoo...that was long...Yeah. More frames = good.", "Movies don't look fine. Watch the edge of the screen, let's say of an aerial fly by shot of mountains. They look so jittery as they pass off the screen.", "Film has motion blur because that 24 fps (usually) captures 0.5 seconds for every second of footage. So each frame is about 0.02 seconds of motion captured in a still image. Games, on the other hand, create each individual frame as one instant in time and won't have motion blur unless it's artificially added in.", "You watch movies but play video games. A movie doesn't matter because you just have to sit there and take it in. Video games you need to control. And the faster you are able to receive the information the faster and more accurately you can respond to it", "When you play a video game, you are thinking of an action to take, you take the action, and you expect instantaneous response from the game. When I'm playing rocket league, I think \"hit the ball now.\" I press the A button and move my thumb stick forward. If the car doesn't instantly flip forward due to lag or whatever else, it's incredibly obvious that something didn't work out. In a movie, you probably don't have any idea what's about to happen and there is no input required from you, so you are a passive observer."], "text_urls": [[], [], [], [], [], [], [], [], [], []], "score": [788, 94, 59, 18, 10, 9, 8, 8, 3, 3]}}, {"q_id": "6030ja", "category": "Repost", "title": "Why is it not recommended to refreeze food that has previously been frozen and thawed?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["df33arx"], "text": ["Condensation/water content/bacteria Doing this can lead to food being incredibly dry or tough. Additionally: if meat sits out for awhile and grows bacteria, that bacteria may not always be killed by the cold that occurs from refreezing and can spoil it."], "text_urls": [[]], "score": [4]}}, {"q_id": "6047wl", "category": "Repost", "title": "the concept of bankruptcy", "title_urls": {"url": []}, "selftext": "I read the wiki page, but I still don't get it. So it's about paying back debt or not being able to do so? What are the different \"chapters\"? What exactly happens when you file bankruptcy? Isn't every homeless person bankrupt? [Related]( URL_0 )", "selftext_urls": {"url": ["https://s-media-cache-ak0.pinimg.com/564x/c2/0c/47/c20c474db5c6a6c5d2025e0faf5fd627.jpg"]}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["df3h6pr", "df3bvc4", "df3cc1r", "df3lvpy", "df3cxrf", "df3rce0", "df3vhes", "df4223z", "df3rirp", "df3cbte", "df3q4h9", "df466r4", "df3qjnr", "df3w50w", "df3pa1e"], "text": ["From the [previous thread]( URL_0 ) - this is a great ELI5 version > Like you're Five: On the day you get your allowance, you buy a bag of candy. The next day, you want more candy, but you spent your allowance, so you ask your brother if you can borrow his allowance, and pay him back with your next allowance. You buy another bag of candy. The next day you ask your sister if you can borrow her allowance, and promise to pay her back when you get your allowance. You buy another bag of candy. > When you finally get your allowance, you realise you're in trouble - you can't pay your brother and your sister. You get so worried about it that you go buy a bag of candy instead. When you get home, you get in a big fight with your brother and sister about it. > When your Mom asks what you're fighting about, your brother and sister tell her that you borrowed money and you won't give it back. She asks you why not, and you say that you spent all of the money on candy, and you don't have any money left. She sighs, and makes you give all the candy you have left to your brother and sister. They want to know when they get their money back, and she tells them the money is gone, and they need to stop fighting with you and forgive you. They say that that isn't fair, and she says that it really isn't, and that they should remember this the next time you ask them for money.", "Declaring bankruptcy is seeking legal protection from your creditors (people you owe money to). As far as personal bankruptcies go, chapter 7 is what people generally think of when they bankruptcy. The courts allow you to discharge your unsecured debts (credit cards, medical bills, personal/ payday loans, civil lawsuits, repossessed vehicles, foreclosed real estate, etc). The entire process takes a few months to be discharged and you also have to income qualify- if you make more than the median income in your state you would have to pay back some portion of your debts. You can only do this once every eight years, it will bring down your credit score as you have demonstrated that you were unable to pay back your debts and creditors in the future might not want to lend to you or only will at a higher interest rate. A chapter 13 is a bit different and can deal with other debts as well as unsecured. You would file this if you make too much for a chapter 7, if you are behind on a financed vehicle/ real estate that you want to keep, if you have a lot of back taxes to pay off or to freeze student loans. A monthly payment would be determined based on which of those debts are being dealt with, how much the debts are and also on your income. You would make this payment to a bankruptcy trustee for 3-5 years and your unsecured creditors would receive a percentage of their debts, secured creditors receive 100% (generally). You would be discharged of any unpaid debts at the end of the bankruptcy. This is an overview of the type I'd give to a person seeking information about filing. Source: legal assistant to a bankruptcy attorney.", "Bankruptcy is a highly nuanced area of the law. With that in mind, I provide the following answers in _very_ ELI5 terms. Let's first make a distinction between \"bankruptcy\" and \"solvency.\" The terms \"bankrupt\" and \"insolvent\" are often used interchangeably in common discussion, but they are entirely different (albeit related) legal concepts. \"Solvency\" refers to a person's/company's ability to pay his or her debts. If you are unable to pay your debts as they come due, you are \"insolvent.\" \"Bankruptcy\" specifically means the legal proceedings in which an insolvent debtor pays, reorganizes, and/or discharges its debts. So in any bankruptcy proceeding, you have a debtor (the bankrupt party) and (usually) _several_ creditors to whom the debtor is indebted. The problem is that the debtor has no way to pay back the creditors. Bankruptcy provides an orderly, judicially-administered process by which the debtor partially satisfies and/or reorganizes its debt. In very general terms, bankruptcy seeks to maximize the recovery for creditors in a way that protects the debtor from being constantly mired in an unending cycle of lawsuits and debt collection. Without bankruptcy, creditors would essentially race one another to the courthouse to try to get as big a piece of the debtor's remaining assets as possible. This would create situations where a debtor's credit card company (for example) could get a 100% recovery on the debtor's credit card debt, while the debtor's mortgage lender (who is owed way more money) gets nothing. As you note, there are several chapters of bankruptcy, which include: Chapter 7, Liquidation - In this chapter, a debtor's assets are liquidated (auctioned off for cash) and the proceeds are divvied up among the creditors. In the context of an individual person's bankruptcy, there are several carve-outs (\"exemptions\") for property that they get to keep, in spite of their debts. If an individual debtor obeys the rules of the bankruptcy court (e.g., doesn't try to hide assets), he'll get a \"discharge,\" which means that (most of) his debts are wiped clean at the end of the proceedings. If the debtor is a company, ALL of its assets are sold and it essentially dies. Chapter 9, Municipal Bankruptcy - A rather uncommon type of case, chapter 9 cases involve municipal institutions that have become insolvent. It permits the reorganization of their debts _kind of_ like a Chapter 11 below. Chapter 11, Reorganization - In these cases, the debtor (usually a business) still has a lot of value and income. It just needs a little help to pay its bills. In a chapter 11, the goal is to come up with a \"plan\" that reorganizes the terms of the debtor's debt. If a plan is successfully confirmed, it becomes the new deal between the debtor and the creditors going forward. Chapter 12, Farmers and Fisherfolk - This is essentially a specific type of Chapter 13 bankruptcy (below) available to farmers, fishermen and the like. These are kind of uniquely positioned debtors because these are often blue collar jobs that require very high capital commitments. Chapter 13, Reorganization - Available only for individual persons who meet specific debt requirements, these are quicker and easier proceedings that permit an individual to reorganize his debts. Chapter 15, International Bankruptcy - Chapter 15 permits creditors or debtors in a foreign bankruptcy proceeding to obtain certain bankruptcy relief in the U.S. So that's it in _very_ broad strokes. If you have any questions, feel free to ask.", "I meet all kinds of people in my line of work. Just because someone is \"homeless.\" Doesn't mean they are broke. They may have more money in their chequeings account than you do. I have met some of these people. They just like the lifestyle of being off the grid and not have to answer to anyone. Weird, but to each their own. One man stands out in the back of my mind the most. Has a cellphone, regular bill and PO Box. Has a Facebook account and is a professional violinist that has seen more of the world than I ever will. He also used to makes violins by hand. And lives on the street. I met him when I arrested him for trespassing into an old factory. He broke and entered to stay warm. As that is not an indictable offence, charges were dropped and he just had to pay damages.", "Why isn't every homeless person bankrupt? Because bankruptcy is a legal thing: it means that the people you owe money to taking you to court. The bankruptcy \"chapters\" are just the rules the court will use. Homeless people tend not to have money, so there's no point in taking them to court. Are there any creditors who would be happy with a scuffed-up duffel bag and a cardboard sign? Answer: no. There's simply no upside to taking a homeless person to court. They have nothing, so the creditors can get nothing.", "Can I declare bankruptcy if I only have $100 in debt?", "One positive thing about the idea of bankruptcy is that it takes some of the risk out of entrepreneurship. If you start a business and it fails and your hundreds of thousands in debt that's going to essentially ruin the rest of your life. Bankruptcy is a kind of safety net so people will be less afraid of taking risks. We want people to start businesses and innovate but it's a big personal risk.", "Sue someone in civil court for damages. Win. Judge bangs gavel. Makes debt appear. File for bankruptcy in bankruptcy court. Follow all the correct rules and procedures. Judge bangs gavel. Makes debt disappear. Chapter 7 is for throwing in the towel. You sell your assets, except those assets which are exempt. The proceeds are divided among your creditors. You get any change leftover. There won't be any change leftover. All of your debts, except for certain kinds like student loans or debts that you got because you hurt someone go away. Chapter 13 is for hitching up to the plow. You agree to work for 3 or 4 or 5 years and some amount of your proceeds go towards your creditors. At the end, all of your debts, except for the same kind mentioned above, go away. Chapter 11 is for reorganization. Businesses with a ton of assets who got too far in debt to dig themselves out can do this. The creditors may take over the company, or you may get to keep it. It depends on what you can bring in and what everyone, including the court, agrees to. Chapter 12 is like Chapter 13, but for farmers. Chapter 9 is like Chapter 11, but for cities. Source: Lawyer, took bankruptcy in law school. Never had a case, though.", "Bankruptcy is when someone borrows more than they are able to repay. Typically, someone who wants to file bankruptcy will go to a lawyer's office for a consultation, where the lawyer will ask a series of questions to determine if that person is eligible to file for bankruptcy. If they are, then the lawyer will determine which type, or chapter, of bankruptcy is best for that person to file under. For individuals, there are two main chapters of bankruptcy: 7 and 13. Chapter 7 is when the person sells their stuff to the companies they owe. In return, the companies will use their debtor's assets to settle their accounts. Typically, people who file Chapter 7 bankruptcy have little to no income, either because they're unemployed, disabled and unable to work, or live off a fixed income, and have very few if any valuable assets to sell to their creditors. Chapter 7 bankruptcy provides immediate relief to debtors, meaning that once the court approves the debtor's case, any and all debts mentioned on the debtor's paperwork are forgiven in full, provided that the debtor meets their end of the deal. Chapter 13 is different from Chapter 7 because under Chapter 13, the debtor gets to keep all of their assets. However, the trade off is that the debts are not immediately forgiven, as they are under Chapter 7. A debtor who files for Chapter 13 bankruptcy is said to 'restructure' their debts. This means that the debtor must make monthly payments to a Trustee, someone who is designated by the state to make sure the creditors receive their money each month. The Trustee also helps debtors by providing them with financial literacy courses. Depending on the state the debtor lives in, they may be required to take a certain number of financial literacy courses from their Trustee to help assure creditors that the debtor can make better financial decisions in the future. The amount that the debtor must repay each month is based on several factors, mostly how much they owe, and the debtor's current income. Debtors are usually required to make payments for 36-60 months, or 3-5 years. The length of time is usually determined by considering how much the debtor will owe against the debtor's disposable income, or how much money is left after the debtor pays for important things like rent, utilities, groceries, etc. Debtors are also required to obtain approval from their Trustee if they intend to take on credit over a certain amount while making payments on their bankruptcy. Credit cards are unlikely to receive approval, but a car loan is more likely to be approved, since the debtor might require transportation to maintain their income. Once the debtor makes all of their monthly payments as agreed upon with the court, any remaining debt is forgiven. Under both and all other chapters, the debtor is placed under legal protection by the bankruptcy court once the lawyer has filed the debtor's paperwork. This means that creditors are not allowed to contact the debtor directly, especially to make collections. If creditors continue to contact the debtor directly, then the creditor may face legal recourse, up to and including the amount the debtor owes. The debtor is protected by the court until the judge discharges the bankruptcy once the judge feels that the debtor has met their obligations to the court.", "I agree with everything said above but would clarify the only time a chapter 13 is 3 years is when the debtor is under median income and would otherwise qualify for ch. 7 but needs to file ch. 13 - perhaps to save a house, car, taxes, etc. Most chapter 13s are 5 year plans.", "Jesus, guys... not many easy explanations in here. At the expense of tanking your credit rating, you can give back all of your assets to cancel all of your debt. Essentially, *you get to start again from zero*. Credit rating is important for running a business, getting a loan, and generally being an adult, so bankruptcy is a tactic of last resort.", "One thing I learned personally is this.. If you get over your head in debt,and feel you must do the \"honorable\" thing and pay it back even if it takes 10 yrs. Consider this...you will be called a deadbeat,cheap bastard and every other name in the book.....When and if you manage to pay it back you will still be called those names not to mention your credit may be shit for paying late...plus all the headaches you went thru. On the other hand,bankruptcy allows you to provide ONE signature to dissolve all of your debt. 2 minutes and it's over! They will for sure call you a deadbeat and cheap bastard when you file bankruptcy..but you'll be far ahead and FREE of debt.", "Bankruptcy is when a court or other body of similar standing recognises that a person or a company can't pay their debt. For a company, the court appoints a lawyer or accountant who figures out how to divide any remaining assets. The previous owners of the company lose their ownership of the company but won't lose more than that, but will be free to start a new company (provided it's a normal type of company). It can get a bit messy, when there is bank debt, debt from other places, pension funds and so on. Often it takes ages to get to a deal and the actual deal is not very good meaning a lot of the value of the assets is wasted. For an individual, I believe the process is similar. The court will appoint an administrator who will work with all the debt holders to the figure out how to divide the assets of the person who went bankrupt. But the court can also impose a penalty on the person, saying they have to pay back X dollars from future earnings, or X% of future earnings.", "A lot of people have made comments and many have a degree of accuracy but also state things that are patently untrue. I have been a bankruptcy paralegal and petition preparer for 7 years. 1. You will not be forced to sell everything you own. The law provides exemptions to cover most, and usually all, of your belongings (including bank accounts). 2. You do not \"qualify\" for bankruptcy because of unpaid loans. Many people have never missed a payment when they file. The only \"qualifiers\" (and I use that term loosely) are income-which will be a determining factor as to which chapter you might file and prior filings. 3. If you file chapter 7 you cannot file chapter 7 again for 8 years. 4. If you file chapter 7, you can file a subsequent chapter 13 even if you received a discharge in 7. 5. If you file chapter 13 and receive a discharge, you may not file a chapter 7 until 6 years from the date of filing. If you file chapter 13 and are dismissed without discharge, you may refine-multiple times even, unless the court bars you from doing so. 6. Chapter 7 stays on your credit report for 10 years but if you manage your credit properly your credit will rebound very quickly and you can get a mortgage in as little as 2 years from discharge. 7. Chapter 13 with a discharge stays on your credit report for 7 years. 8. Chapter 13 dismissed without discharge stays on your report for 10 years. There were more but those are some highlights.", "Bankruptcy is a way to deal with owing too much money in an orderly fashion. There are a couple of ways to deal with people and businesses who owe too much money, each in a separate \"chapter\" of the Bankruptcy Code. Because other answers deal with how bankruptcy protects the person or company owing the money (the \"debtor\"), I'll focus on why the people **owed** the money (the \"creditors\") want bankruptcy. There is something called a \"scramble for assets.\" If there isn't enough money to pay off all the debts, each creditor wants to make sure *it* gets paid first. That's especially true when you consider that creditors don't look to sell property they've seized to pay a debt for the highest price\u2014anything over the amount they're owed gets returned to the debtor\u2014so a creditor might squander an asset, leaving less for both the debtor and other creditors. Consider a single piece of commercial property secured by two mortgages. (We'll make it commercial property so there are no problems foreclosing on it, or seizing it to pay the debt). Let's make it a $5 million asset, say that the loan used to buy it has been paid down to $2 million, and that the company then took out another $2 million loan to pay for expansion. So we have a $ 5 million asset securing $4 million in loans. But if the first company forecloses, it has no incentive to sell the property for more than $2 million. If it sells it for $4 million, the second creditor might be happy (there is $2 million left to pay it), but the debtor can reasonably ask, \"Where's my other $1 million?\" Even worse, if the foreclosing creditor sells the property for $3 million, now the second creditor has lost $1 million that really it had a right to. It used to be owed money by someone whose assets were worth more than their liabilities: now it is owed $1 million by someone without any money. So, what we want is an orderly way to decide who gets paid and when. There seem to be some fair rules that we can agree on, and we want to enforce those rules. Creditors who loan money on the debtor's promise that they can foreclose on property (\"secured\" creditors) should not have to worry about a creditor without a mortgage or lien (an \"unsecured\" creditor) taking the property, selling it, and keeping the money. Employees who are owed back wages should get paid before money goes to a company's other creditors. Etc. Also, at some point we want to give individuals a fresh start. Imagine if you owed $3 million because a jury found that the reason a warehouse burned down was because you were negligent in flicking a cigarette butt. You would like to be able to earn some money without having the creditor take it away before you could spend it on food, let alone rent and your children's education. And not everyone who misses a payment needs to have their debts wiped away. Maybe they can pay all their creditors *without* anyone seizing their assets if they are given a little bit more time. So everyone wants their to be an orderly way to deal with a debtor who isn't paying his debtors, and most people want there to be some relief extended to debtors. Thus, the Constitution allows Congress to establish uniform rules for bankruptcy that overcome any state laws (the process for actually seizing property and enforcing debts comes from state law), and Congress enacted the Bankruptcy Code under that authority. The \"order\" bit gets guaranteed by something called the \"automatic stay.\" Either the debtor (or creditors worried that there will be a scramble for assets) can file a \"petition\" with the local bankruptcy court, and as soon as it is filed, no one may try to collect any debt from the debtor. No new lawsuits may be filed, no foreclosure actions may be initiated or continued, and all lawsuits already filed are paused until the bankruptcy court says otherwise. The bankruptcy court will decide what happens next based on which \"chapter\" of the Bankruptcy Code the petition was filed under. Other posters have described the chapters well enough. In any event, unless the debtor really doesn't have any assets to distribute and is only looking to have his or her debts wiped away under Chapter 7, the creditors then file \"claims,\" saying the debtor owes them such and such. Then the bankruptcy court decides what debts are actually owed, which debts are secured by assets and which are not, etc. That is known as the \"claims allowance process.\" Then, everyone gets together and comes up with a plan. The creditors are told what assets will be sold, who will sell them, how the money will be distributed, etc.. The debtor can usually protect some assets if he or she is an individual (e.g., forestall foreclosure on his or her only house). If the debts are going to be restructured, a payment plan gets worked out. Usually, every creditor gets paid less than they were owed (unless there were assets enough to satisfy the secured creditors), but more than they could expect from a scramble for assets. The plan gets confirmed by the bankruptcy judge, the debtor follows the plan, and voila! no more bankruptcy. Now, as you can imagine, that is an expensive process. And one of the groups of people who are assured of being paid (other than employees with back wages and the government owed its taxes) are the lawyers. So, to your last question: every homeless person could probably have all their debts wiped away by filing for bankruptcy. But they have no assets, so there is no real danger of a scramble for assets. And because they will never pay their debts back anyway, no one cares about whether those debts were discharged in bankruptcy or just go uncollected. Creditors don't hound homeless people for the simple reason that hounds are expensive. So, not a lot of homeless people end up in bankruptcy."], "text_urls": [["https://redd.it/jerb3"], [], [], [], [], [], [], [], [], [], [], [], [], [], []], "score": [3264, 1828, 85, 28, 14, 8, 8, 7, 6, 5, 4, 3, 3, 3, 3]}}, {"q_id": "604v52", "category": "Repost", "title": "What is the trail an airplane leaves behind when it flies through the sky?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["df3kkgy", "df3glri", "df3hytg"], "text": ["Take a water bottle and drink most of the water. Then, close the cap. Twist the bottle so that it is pressurized and split into two sections. Quickly take off the cap, you will hear a loud POP. In that moment, the air goes from high to low pressure. And if you look at the bottle, it will be emitting a little cloud of water vapor. The same thing is happening with the planes. All of the pressure systems about the wings forms water vapor clouds behind the plane.", "water. URL_0 with a few impurities due from the incomplete burning of fuel, but basically just water. (or ice)", "Just for interest sake, currently being in Europe I see it a lot. I noticed it in France and now while in the U.K. It was very new to me as I had never seen them caused by planes while living in South Africa. Not to say it doesn't happen there but it's definitely something I had never seen before and I lived about 10km from O.R Tambo Airport (Johannesburg)."], "text_urls": [[], ["https://en.wikipedia.org/wiki/Contrail"], []], "score": [13, 12, 3]}}, {"q_id": "604ywf", "category": "Repost", "title": "Why do things that are spinning at a fast rate (airplane propellers and car tires) seem to reverse direction?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["df3ii7x"], "text": ["It's something that is commonly known as the \"wagon-wheel\" effect. Cameras record footage not continuously, but by capturing a series of images in quick succession, at a specified frame rate. With many movie cameras, that rate is 24 frames per second. When the frequency of a wheel's spin matches the frame rate of the camera recording it (say, 24 revolutions per second), each of the wheel's spokes completes a full revolution every 1/24 seconds, such that it ends up in the same position every time the camera captures a frame. The result is footage in which the wheel in question appears motionless. So when a wheel seems to spin in a direction opposite to its actual rotation, it's because each spoke has come up a few degrees shy of the position it occupied when it was last imaged by the camera."], "text_urls": [[]], "score": [5]}}, {"q_id": "6053lx", "category": "Repost", "title": "What power does the British Monarchy actually hold? Versus the Prime Minister and Parliament more specifically. What can or can't they do with it without the permission of Parliament or the Prime Minister?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["df3oye6", "df3it76"], "text": ["The British Monarchy is a great example of the *\"de jure\"* (\"matter of law\") vs. *\"de facto\"* (\"matter of fact\") distinction. The Queen holds power *de jure*. The government is run in her name and on her behalf. She appoints Prime Ministers and criminal prosecutions are brought in her name. But Parliament and the government (\"Government\" in UK politics refers specifically to the prime minister and some of the prime minister's secretaries and ministers) hold power *de facto*. They decide what the laws are and whether to puruse criminal convictions. The Queen has almost no *de facto* power. She can't pass laws, she doesn't have a say in her salary or income (formally), and while she \"advises\" the Prime minister at a weekly meeting, the prime minister is under no obligation to listen to her.", "The British monarchy owns a bunch of land that they turn over to Parliament to administer in exchange for their annual stipend, though they could, in theory, say \"nah, we'll just manage it ourselves\" (though in reality this would probably not fly). As far as political power is concerned, the political power of the monarch, and this actually holds for most parliamentary systems whether their head of state is a figurehead president or a monarch, is to designate which party will lead negotiations to form a government after an election. In principle, this is really a non-power, particularly in the UK where absolute majorities in parliament are the norm: The monarch just names the designated prime minister from the majority/plurality leading party as the Formateur (person who leads negotiations to form a government). However, in some cases, supposedly toothless monarchs have used this power to affect political change. I know in some cases the monarch has been to some extent involved in the actual coalition formation. For example, in Belgium in 2007-2008 there was something of a constitutional crisis between the Walloon and Flemish populations and there was a ton of difficulty in getting a coalition together. It's pretty widely believed that the King was putting a lot of pressure on the parties to come up with a deal to avoid worsening the crisis."], "text_urls": [[], []], "score": [6, 4]}}, {"q_id": "605p9j", "category": "Repost", "title": "Why can't we freeze food twice?", "title_urls": {"url": []}, "selftext": "I always hear that it's because bacterias can grow faster but it doesn't make any sense, they would grow faster at a higher temperature anyway so why shouldn't we freeze food again after unfreezing it?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["df3o4d9"], "text": ["This is a myth. You can freeze and re-freeze food as much as you'd like, because the freezing process kills bacteria. The optimum temperature for bacterial growth is close to body temperature or higher for many bacteria (40\u00b0 F and 140\u00b0 F). This is the \"danger zone\". What you don't want to do is refrigerate food over and over again. Or freeze a giant meal, reheat the whole damn thing and let it sit out on the counter for a while, then refreeze the whole damn thing again. If you take a meal out of the refrigerator, heat it a little, then put it back in the refrigerator, you're bringing the temperature up into the \"danger zone\". If you do this over and over again, you allow the bugs to multiply a lot. Freezing rapidly can kill these bacteria. But you also have the risk of the toxins from the bacteria in your food (which will not be removed via freezing). Check out the [USDA's page regarding leftovers]( URL_0 before Republicans remove it from the website. The best thing you can do is take leftovers as soon as you eat the food and separate them into smaller quantities for freezing. Then only bring out one portion at a time, heat it and eat all of it. Putting it back and forth into the fridge can be dangerous."], "text_urls": [["https://www.fsis.usda.gov/wps/portal/fsis/topics/food-safety-education/get-answers/food-safety-fact-sheets/safe-food-handling/leftovers-and-food-safety/ct_index/!ut/p/a1/jZFRb8IgEIB_jY_06OpM3VvTZNFutjNmE_tisAVK0kIDzG779UP3ootuck_cfV_g7qAEAqWieymok1rR9nAvJ1u8xJNwmuKsmIaPeJ6_LYunNMXx6t4Dmz-APLrRv3IS_J-f3fDAnVmkCwFlT12DpOIaiGAOUWUHZiwQrnWNLOXMfSJOK4dsw5jzhUMOHasNVXUrlQDSMu703nver9GJCqRyW6lq9gFrKM-_hUMf8zxajWdZHuFi_Bu4MLcf4PpgfOei1bvjkjaJ2kWxb9Ewzgwzwbvx6ca53j6M8AgPwxAIrUXLgkp3I3xJabR1QM5J6LtX8vWczLB"]], "score": [4]}}, {"q_id": "607mk2", "category": "Repost", "title": "Why does our moon not spin at all?", "title_urls": {"url": []}, "selftext": "Ive always been so confused why we always see the same side of our moon when most objects in space seem to spin.", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["df43urx", "df4448u"], "text": ["The moon spins at the exact speed where one orbit around the earth (28 days) is the same amount of time it takes it to spin around its axis. It is [tidally locked]( URL_0 ).", "The Earth's gravity slightly distorts and elongates the moon. This means if the moon tries to rotate, this elongates axis gets pulled back into line with the Earth. The Moon does, on fact, wobble back and forth as this effect occurs. This effect is called 'tidal locking'. A long time ago, the Moon did rotate, but this effect slowed and eventually lockes the Moon in the current position."], "text_urls": [["https://en.wikipedia.org/wiki/Tidal_locking"], []], "score": [19, 4]}}, {"q_id": "607vxu", "category": "Repost", "title": "how do reality shows record illegal acts in series?", "title_urls": {"url": []}, "selftext": "Like moonshiners or street outlaws, those are illegal things people are doing in the show so how do they record the footage and not get in trouble?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["df45zcy", "df48o9u", "df4co8l", "df48j3t", "df48219", "df4cqlq", "df4g18n"], "text": ["You generally can't prove from the footage whether or not the acts are actually illegal, or just fake reenactments for the show. And police generally have more important things to worry about then trying to hunt down possibly-fake moonshiners. You know, like solving actual murders, or responding to victims of domestic violence.", "It's not illegal to film a crime so that let's the studio off the hook. Most reality shows are fake. Producers either help create situations or suggest reactions. I honestly can't watch much of it at this point. You would think it would be obvious to everyone at this point.", "Moonshiners and Street Outlaws are both fake. All the drama is 100% scripted and no laws are being broken. Moonshiners doesn't actually film anyone who makes\u200b any liquor. You really think cops would leave a note saying \"we'll get you next time\"? Street Outlaws pays local law enforcement to close the street, just like any film set closes down stretches of city road and has an ambulance and emergency crews on standby. They also buy giant lights to illuminate the street so they can film. Not to mention the drivers are all members of NHRA, which is very strict about illegal racing.", "Reality tv is all fake, police wouldn't bother with people pretending to break laws for crappy tv.", "The same way they film them for every other film and and tv show, it's not illegal if it's fake.", "In many countries including the USA and the UK you are generally not required to report any suspected crimes to the police. Provided they do not cross the line into aiding and abetting, the camera crew and TV producers are not breaking any laws even if the stuff they're filming is illegal.", "There have been reality series that ended because acts aired on tv were investigated and people were charged. As far as film crews documenting said \"crimes\" they fall in the category documentary journalism. A third party that does not partake but is there to merely document events. As long as they do not actively involve themselves beyond this they cannot be charged with accessory, aiding, or any other involvement charges."], "text_urls": [[], [], [], [], [], [], []], "score": [35, 15, 14, 9, 7, 3, 3]}}, {"q_id": "6088ov", "category": "Repost", "title": "Why climate change is happening and why it's bad", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["df4bwin", "df498r3"], "text": ["#What's happening and why? So very basically, carbon dioxide (CO2) is a \"greenhouse gas\". That means that CO2 absorbs heat very well and radiates it back towards the earth. Sunlight goes in, heat comes out, and heat from the earth gets trapped here like CO2 is a blanket. Sure, the Earth still radiates some heat away, but not as much as it used to. The more CO2 there is in the atmosphere, the worse the effect is. There are other greenhouse gases involved, too, like methane, but CO2 is the big one. Even though methane does it better, there's just *so much* CO2 that most of the warming comes from that. As the Earth warms up, it melt some of the polar icecaps. [In this gif]( URL_10 ) you can see the ice slowly shrinking over time. Keep in mind that's the average: the ice partially melts in the summer, then refreezes in the winter. Unfortunately, it's melting way more than refreezing right now. That's a huge problem because that ice is very reflective and can reflect a lot of sunlight away from the earth. Less ice means more sunlight is getting absorbed and turned into heat. So the earth is warming even faster. The oceans hold a lot of dissolved CO2, and as the water heats up a lot of that CO2 ends up getting released into the atmosphere from deep in the ocean, making the earth warm up *even faster*. At the same time, there's a lot of CO2 getting absorbed into the oceans, which makes the water more acidic which is harmful to marine life. Regardless of what mechanisms are currently running out of control, it's pretty much accepted by the vast, *vast* majority of scientists that humans started it and are still contributing to it significantly. Every time you burn something, particularly a fossil fuel like gasoline or coal, you produce CO2. [Here is a graph of the atmospheric CO2 concentrations over several hundreds of thousands of years]( URL_0 ). You'll notice it's mostly cyclical - it rises a bit, then falls a bit, then goes back up. It's cyclical even during a single year. During the northern hemisphere's spring and summer, the huge swaths of forests in Northern American and Siberia absorb literal millions of tons of CO2 during photosynthesis and trap the carbon in sugars and cellulose. Then, during the winter months, the trees shed their leaves and stop photosynthesizing as much, relying on the food they stored during the summer and releasing a significant chunk of CO2 back into the atmosphere. However, this past year in September, when the CO2 concentration will be at its lowest point of the year as the trees finish the summer photosynthesis, the CO2 concentration was *higher* than it normal would be at the end of *winter*. [Here's a chart of CO2 for the last several decades]( URL_5 ). CO2 last year reached [400 pmm]( URL_7 ), which is higher than it has been in 4 million years. We know what CO2 levels have been for millions of years by, among other things, looking at arctic and antarctic ice deep inside glaciers. That ice has been frozen and compacted under more layers of ice for millions of years, and we can test that ice and compare it to ice formed recently, and from that we can get a very good idea of how much CO2 was in the atmosphere. We can also compare tree rings and look at chemical concentrations in those samples from very old trees (even fossilized trees), as well as [looking at coral skeletons]( URL_8 ) and comparing the concentrations of certain elements. So don't let anyone tell you that we don't actually know, because scientists are studying a *lot* of different data points. [Here is XKCD's excellent temperature timeline that really helps give the scale of what's happening]( URL_2 ). The earth's average temperature is skyrocketing. Why a one or two degree change may not sound like much, remember that it's the average for the entire planet, which means there are going to be some really wild swings to get the average to move. Again, look at the XKCD timeline and consider that for tens of thousands of years the average temperature barely changed by 4 or 5 degrees C, and 4C lower than the modern average was an ice age. **TL;DR:** Humans make a lot of CO2 through industry and burning fossil fuels. CO2 is like a blanket for the Earth: it traps heat whether we want it to or not, which causes more problems that cause more warming which cause more problems, etc. #Why is it bad? Melting ice increases the volume of the oceans, along with the slight thermal expansion of the water as it heats up. That could threaten a lot of coastal cities, and since [most of the world population lives in coastal cities]( URL_6 ), that is a problem. More than likely, they won't be underwater, but they'll probably look a lot like Venice in a bad way. That also means storm surges will push farther inland, causing massive damage and making life in those coastal cities untenable, even if the buildings are literally underwater. The melting ice also affects ocean currents. The major currents are driving by temperature extremes as warm, less dense water from the tropics flows to the poles, where it gets colder, denser, and sinks down, creating space that vacuums more warm water from the tropics, and so on. But the fresh water melting from the icecaps, cold though it is, is still less dense than the saltwater. So it doesn't sink down, and instead is filling the space the warm water from the tropics would normally fill. That disrupts the ocean currents, and ocean currents drive the Earth's climate in the same way that the poles and equator drive the ocean currents - warm water heats the air above it, bringing warm, wet air over parts of the Earth that are far north and would normally be very cold without those currents. So England goes from being chilly but mild to being *very* cold. That also means less warm, wet air going over places where it normally becomes rain, leading to widespread drought. It's no coincidence that much of the US, particularly California, is experiencing the worst droughts we've had in hundreds, if not thousands of years. At the same time, those shifting weather patterns create more intense weather, so you see more and worse hurricanes, and more destructive storms that cause dangerous flooding. Which is why the American Southeast is simultaneously in the worst drought in hundreds of years *and* got hit with the worst flooding we've seen in hundreds of years. Less rain means less food. You can't grow crops without water, and you can't exactly truck water thousands of miles from the ocean to your wheat farms. The changing climate [has already destabilized parts of the world]( URL_1 ) that can't handle the droughts and associated food shortages. Many coastal communities are dependent on the ocean for food, too, with fishing. But remember the ocean becoming more acidic in addition to warming up? The coral reefs are incredibly delicate webs of life and the increasing temperatures and acidity are killing the corals [throughout the Earth's reefs]( URL_4 ). No corals means no things that eat corals, no things that hide in corals, no things that eat those things, and so on, destroying a vast food web with far-reaching implications that we can't fully understand. We're already overfishing, disrupting the ocean's food webs and running out of viable fishing options for us, so the fact that the reefs are dying is apocalyptically bad news. [We are almost certain already experiencing a mass extinction event]( URL_3 ). There is a normal background level of how many things go extinct, and we are currently experiencing extinctions at thousands of times that normal level. Biodiversity is important for preserving the delicate food webs around the world. Say one bird dies, but turns out that bird eats an insect that eats flowers, so those insects run amok and destroy huge fields of flowers. Bees rely on those flowers for food, so the bees die off, and since bees pollinate our food crop trees like apples, [without bees you don't get apples]( URL_9 ). That's one small example out of the millions of species living on Earth. Humans might be able to live when white rhinos and giant pandas go extinct, but there are a lot of species we *can't* live without. And of course, the Earth is also just getting really hot. That may not sound like a big deal, but consider how god-awful the southeast can get in the summer (I live in GA; in the summer GA turns into Satan's swampy ass crack). It's just going to get worse, and it can get *dangerously* warm, so that heat stroke just from being outside is a real possibility. So the Earth may simply become incompatible with human life. Which is obviously undesirable. We may also trigger a new ice age as the changing climate patterns cause a rapid, out of control cooling of the Earth, which would do everything above in the opposite direction (too cold for crops, too cold for species so it cripples biodiversity, etc.). **TL;DR:** Earth may literally become unlivable for humans. Species we depend on for food are dying off because they can't adapt to the changes, and we may not be able to find new solutions. War, famine, etc. are real possibilities in the coming decades.", "I think this has been asked about 5000 times now. Did you try the search function?"], "text_urls": [["http://assets.climatecentral.org/images/made/5_2_13_news_andrew_co2800000yrs_1050_591_s_c1_c_c.jpg", "https://www.nytimes.com/2015/03/03/science/earth/study-links-syria-conflict-to-drought-caused-by-climate-change.html", "https://xkcd.com/1732/", "http://www.biologicaldiversity.org/programs/biodiversity/elements_of_biodiversity/extinction_crisis/", "http://news.nationalgeographic.com/2016/03/160321-coral-bleaching-great-barrier-reef-climate-change/", "http://www-das.uwyo.edu/~geerts/cwx/notes/chap01/mauna_loa_co2.gif", "http://i.imgur.com/aZndj0s.jpg", "http://www.climatecentral.org/news/world-passes-400-ppm-threshold-permanently-20738", "https://www.youtube.com/watch?v=aXmCU6IYnsA", "http://www.foxnews.com/food-drink/2012/07/19/10-crops-that-would-disappear-without-bees.html", "https://upload.wikimedia.org/wikipedia/commons/3/33/Arctic_sea_ice_loss_animation.gif"], []], "score": [6, 4]}}, {"q_id": "608g3k", "category": "Repost", "title": "Why can hard cheese age for months while being made, but once they hit the grocery store shelves they only last a few weeks at most?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["df4bcgv"], "text": ["Cheese only \"ages\" under the correct conditions, usually a specific temperature and humidity range (often around 55 degrees F). Too warm, and the wrong microbes get involved, too cold and the ones you want die, moisture condenses, etc. Often cheese is carefully maintained, rotated, brushed, brined, that kind of thing, during the aging process. Other cheeses form a thick rind which acts to keep out undesirable microbes and oxygen. Still other cheese are dipped in wax to seal them, and something like Muenster is swabbed with a bacterial solution to ripen it. Some cheeses, especially the soft cheeses like brie or camembert just have a given lifespan, and there is no magic about being sold at a shop. You buy them, and usually hold on to them until they hit their peak. Hard cheeses though can be aged for an *extremely* long time, whole, in the right conditions. Once you cut it up and take it out of those right conditions though, game over... it's like cutting a flower; you can delay the inevitable, but it's just a delay. Then you have something like parmesan, which can last pretty much forever in a store or anywhere else you care to put it. Cheese has many varieties, and some need to be eaten within days of manufacture, others are best after years in a dark, cool place, and everything in between."], "text_urls": [[]], "score": [5]}}, {"q_id": "608vv6", "category": "Repost", "title": "Why do we close our eyes when kissing? Is this innate or learned?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["df4gc5j", "df4fvs0", "df4ifp3", "df4kx6t", "df4klwa", "df4hzej", "df4o7n2", "df4ia66", "df4n7x2", "df4jug4", "df4k2lg", "df4k1ni", "df4ni6u", "df4g93u", "df4ln6p", "df4mbwx", "df4j0wv", "df4kooe", "df4lg16", "df4fxp0", "df4n3y4", "df4nzil", "df4mepm", "df4tsu7", "df4mcgw", "df4lc7d", "df4llo4", "df4saeq", "df4te9j", "df4t59n", "df4q5pj", "df4m9e5", "df4j8xr", "df4nhnz", "df4jrx6", "df4kycx"], "text": ["[It's because we want to focus on the kiss.]( URL_0 ) We have learned to rely more on visual stimuli than on tactile so in the brain visual stimuli is superior. That means that if we kiss with our eyes open what we see will be at the center of our attention rather than the subtle feeling of kissing. If we close our eyes on the other hand it's a lot easier to focus on the kiss. You can try this on your own. Have someone kiss an area on your back. You won't feel much. Then close your eyes and try again, the feeling will be more intense ... Edit: Added source.", "Because it's awkward to stare someone in the eye while you suck on their mouthparts, which is what it becomes if your eyes are open. Also, my understanding is that kissing is thought to be an entirely learned behavior for modern humans, despite some evolutionary basis for the practice. But those explanations (kissing was about pre-chewing tough food for infants and grew into a sign of affection by representing this maternal behavior) still revolve around the kissing *symbolizing* something, so I would classify it as a cultural trait rather than some sort of innate behavior like sneezing or seeking valuable nutrients in food.", "We tend to close our eyes any time we are really enjoying a sensation. A spoonful of delicious ice cream, a juicy cut of steak, etc. It helps us by eliminating other input and allowing the brain to focus on the enjoyable sensation.", "Personal antidote tells me that it's learned, because my first girlfriend yelled at me for not closing my eyes.", "Sometimes I open my eyes to check if my SO is opening her eyes, if she is we laugh and I ruin the moment if she's not I close my eyes and continue.", "Ever smelled something. Like really, really smelled something? What did you do? You closed your eyes, leaned back, and probably let out a big sigh after. When we do things, especially sensory things, we use body language to express what we are doing, even if doing so doesn't really help us achieve the task. We close our eyes when we use the other parts of the face so we can focus on what we are doing and ignore everything else. Also try kissing with your eyes open sometime. It's kinda fun.", "This is not an answered question, although there are answers for *similar* questions, which you've gotten many of here.^1 To say it's innate means it happens on its own and automatically. Many people here are saying it's because your brain can't handle the stimuli of both the kiss and visualization. However, that does not make the act of closing your eyes innate. For many people, myself included, it feels more natural leave the eyes open. Interestingly, [monkeys do not necessarily close their eyes while kissing.]( URL_0 ) So my guess is that it's not innate because it's not universal, but I don't have a hard-and-fast study to back this up. 1: In Thinking, Fast and Slow, Daniel Kahneman points out that when faced with a question we can't answer, we often substitute a similar yet easier question *without realizing it.* For example, if we can't answer the question, \"is this behavior innate?\" we may instead answer the question, \"is this behavior influenced by some biological limitation which makes the result of closing our eyes more likely?\"", "I know why my girlfriend closes her eyes when we kiss. She hates seeing me enjoying myself.", "In middle school I saw a girl kissing her BF with her eyes open. It kind of looked like she was eating his face. It was weird enough to still remember it 20 years later.", "This is not common in all cultures. In Asia, we tend to keep our eyes open, to watch out for predators.", "When showing affection, a general rule of thumb is to do anything within your power to prevent the other person fleeing the room in horror.", "Because a kiss is about intimacy, it moves beyond liking what you see and showing the other person, in very gentle and harmonious way how you feel while allowing them to share the same things with you. You experience so much sensory input during a good kiss that having your eyes open during one detracts from the experience. Kisses are like beer, proof God loves us and wants us to be happy. Close your eyes and experience one for what it is. Her breath, her scents, the smell of her makeup, shampoo and lipstick and everything. Her being in your space and you in hers and that being better than ok. And then her lips, her thighs against yours, her hands closing tightly on your hips to guide you closer ... man kisses are the best... shut up and close your eyes.", "It is learned. Young children kiss with their eyes open. Young teenagers will kiss in the same manner but they quickly learn this \"kills the mood\". Get into someone's face with your eyes wide open! It's intimidating and used as such as a tactic. We close our eyes to convey trust, emotion, and pleasure, but it is learned. Kittens keep their eyes open when being pet, as do puppies. But cats and dogs learn to convey their trust, emotion, and pleasure, by closing their eyes. edit: typos", "Just some insight... I have a pair of Devon Rex's , my sister immediately noticed that my female closes her eyes when I kiss her nose, she squints and lets me do it. My male on the other hand..., eyes wide open.., and recoprocates with thorough nose licking.", "I was once told in a lecture that people started kissing with their eyes closed because they saw people do it in movies. They did it in movies because apparently kissing with your eyes open looked really weird. However, I can't find any articles to corroborate this so I'm starting to have my doubts it's true. Kind of a plausible theory at least?", "I think that Top Gun explained it best when they sang You never close your eyes any more when I kiss your lips And there's no tenderness like before in your fingertips You're tryin' hard not to show it, baby But baby, baby I know it You've lost that lovin' feelin' Whoa that lovin' feelin' You've lost that lovin' feelin', Now its gone, gone, gone whoaohoh", "Speaking as someone who enjoys looking into her partner's eyes at some times and just closing them and sinking into it at others, it's learned.", "Too close to focus properly, hair touching face causing reflexive blink. That and it's awkward as fuck to be staring at someone that close", "Yeah, I don't do that. My current girlfriend thought it was really odd when so opened her eyes and saw me starring at her. Now she's loves it, we always kiss with out eyes open.", "The brain has difficulty processing physical stimuli and visual stimuli, which means trying to focus on both the visual aspects of keeping your eyes open and the tactile essence of kissing is unnecessarily difficult to do for your brain. Given that there is little to no reason to be looking at something so closely as your eyes could not effectively focus on it anyway, your brain just automatically tells you to close your eyes and fuckin' focus on kissin that chick, man!", "Because stuff that close to our eyes gets blurry. our eyeballs are roughly a 50mm lens. If you've ever tried to focus a camera lens on something too close it keeps trying and trying to focus and nothing happens. IT hurts my eyes to keep trying to focus on something way to close.", "Psychologists at Royal Holloway University show the brain is unable to cope with the combination of visual data and tactile sensation of kissing. It used to be thought that people closed their eyes while sharing a kiss because their vision could not focus on something as close up as the other person's face.Mar 20, 2016 If you would like to read the full article, follow this link: URL_0", "Why do girls lift one foot while being kissed?", "Kissing is weird when you think about it. Thinking of having a persons tongue in my mouth is generally disgusting. However, it is very appealing if I'm attracted to the person. Weird with a capital G.", "I keep my eyes open and many a girlfriend has yelled at me because they think it's weird. I have to consciously remind myself to close my eyes sometimes because every girl I've ever kissed hates it. But kissing kinda seems dumb anyway. Just sucking on each other's mouths...", "Story time. I had to learn to close my eyes. My first kiss I a) did the goldfish - technique got rated 0/10 and b) had eyes wide open, no blinking... she was a foot shorter than me and very petite but my survival instincts said if you close your eyes you will make yourself very vulnerable... So for me closing eyes when kissing was learned.", "My girlfriend kisses with her eyes open, it's weird. I have been caught out trying to watch tv while kissing because she doesn't close her eyes.", "Am I the only person who sneaks peeks when I'm kissing?", "I would say learned since I always had my eyes open when I met my boyfriend but he said it was weird. I still peek.", "Prob cause it's too strainful on the eyes trying to focus...Not to mention it's super awkward staring someone in the eyes that close while kissing...Try it without laughing.", "I have my eyes open when I kiss the majority of the time. I only close them sometimes because it feels awkward to have them open when everyone else closes them..", "I kissed a girl in school with my eyes wide open like a fish ,, and I got made fun of for at least a year . It was hilarious, I never made that mistake again . It's definitely learned", "Personally I can't help but to close my eyes cause it's just so enjoyable. People that have a partner can definitely relate to this I believe. And for those that they don't have I'm pretty sure they will find out when the time comes.", "Learned for me. I very clearly remember thinking \"Wait. She closed her eyes. Does that mean I should? Probably. Maybe she's just really enjoying it? No. That's unlikely. Yeah. I should close my eyes.\" But by then I'd overthought it, and ended up missing. She ended up asking if I was trying to eat her nose. We didn't date long.", "Because kissing with your eyes open is like staring in surprise as a predator tries to eat your tongue. Well, to most people at least! It's learned and reinforced by negative attitudes towards kissers who keep their eyes open. Kissing itself varies aming cultures, both in intensity and type. Of course, focusing on tactile stimuli etc. provide and extra incentive to keep those eyes closed, but kissing is (to begin with) a learned act.", "The hardest part of your question is if it's learnt or innate because some of what we think is innate is actually learnt, for example, since children we see people kissing on movies or TV and they close their eyes while doing it, so we may pick up on that since there are many ways of learning. Personally, I think (and there is no scientific background behind my proposition, so bear with me) that we close our eyes because we are engulfed by a moment of utter intimacy when we become one with another person."], "text_urls": [["http://www.telegraph.co.uk/news/12199716/Revealed-The-reason-why-we-close-our-eyes-while-sharing-a-kiss.html"], [], [], [], [], [], ["https://www.youtube.com/watch?v=ca0na8NrOhs"], [], [], [], [], [], [], [], [], [], [], [], [], [], [], ["http://www.telegraph.co.uk/news/12199716/Revealed-The-reason-why-we-close-our-eyes-while-sharing-a-kiss.html"], [], [], [], [], [], [], [], [], [], [], [], [], [], []], "score": [5521, 1300, 652, 341, 282, 140, 120, 109, 101, 98, 74, 69, 43, 26, 25, 24, 15, 11, 8, 8, 7, 7, 6, 5, 5, 5, 4, 3, 3, 3, 3, 3, 3, 3, 3, 3]}}, {"q_id": "609qv3", "category": "Repost", "title": "Why has it been so challenging for humans to create artificial wings?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["df4l007", "df4l5ws"], "text": ["Birds have hollow bones and muscle structures designed for flight humans do not posses these things currently", "Birds have hollow bones, no teeth, and a very different respiratory system to get more oxygen. Massive chest muscles. Very high wing to body weight ratio to reach a similar wing to body weight ratio you'd need wings like 25 feet across and chest muscles the size of a washing machine. Think about the size of the wings on a hang glider or ultralight aircraft compared to the size of the person URL_0 Take a look at this ultralight plane. Imagine instead of a small combustion engine it's an extra 75 pounds of muscle attached to his ribs, and then his arms would have to be wings as big as the wingspan of that craft. We just can't have wings that big powered by puny human muscles! Gliding is much easier, you have hanggliders and wingsuits, in both cases you need to climb or fly to an elevation because you don't make powered lift. Jetpacks have the right power ratio and size, but fuel and *searing hot exhaust* is a major issue. A gliding wingsuit is pretty much the closest you can get."], "text_urls": [[], ["http://www.ultralightnews.com/_media/img/large/quicksilver-mx-ultralight-aircraft.jpg"]], "score": [4, 3]}}, {"q_id": "609ykf", "category": "Repost", "title": "If raising our heart rate through exercise is healthy why is raising our heart rate with stimulants like caffeine considered bad for our hearts?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["df4n9vk", "df4mor4", "df4mz76"], "text": ["It is dangerous based on how it causes heart rate increase. With exercise, you are increasing the muscular need for oxygen and, therefore, the cellular response from muscle to blood stream is to increase heart rate and blood flow to those muscles. Your heart rate increases, blood pumps faster, your breathing increases to increase oxygen turn over, the process continues. However, with amphetamines, you bypass all that natural signalling and cause increased heart rate and vascular constriction with no target for exchange of oxygen or co2. As such, that same reaction is dangerous without an outlet, if that makes sense. Your pumping massive amounts of blood and elevating a heart rate with no way of alleviating that pressure in the system. Your muscles aren't\u200b needing the extra blood flow so your circulatory system is just pounding away. That kind of stress is unhealthy for the system because there is no outlet (the muscles, liver, and brain don't need the extra blood flow so it's just zooming around increasing pressure within the system). Also it's a neurochemical reaction so the stimulant binds to receptors in the brain and 'fakes' the need for increased 'fight or flight' reaction so there is adrenaline in the reaction which isn't as present in exercise. The whole process is more physiological stress than healthy physiological need. The drugs fake a need, cause an extra reaction, and ultimately cause stress on a system. Repeated stress will cause system failure eventually. I hope this makes sense.", "hoping this gets alot of replies since i am curious to know too, my theory is probably that exercise is natural and caffeine is a drug that can activate the fight/flight response which is adrenaline", "When you exercise you can control the rates of your heart. You can speed it up or slow it down through alternating between exercise and resting. With chemical stimulants you can't regulate your heart. Your heart is on, full speed, all the time. It gets worse with harsher chemicals than caffeine. Imagine redlining your car engine for extended period of time."], "text_urls": [[], [], []], "score": [6, 4, 4]}}, {"q_id": "60aej7", "category": "Repost", "title": "Why did the Concord stop flying ?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["df5eu6s", "df4rtf5", "df4tzn7", "df4tg3d", "df4qi7v", "df4y36p", "df524dm", "df4yekp", "df4xasj", "df4uv2b", "df50b5z", "df4yz1k", "df4xnar", "df4z36b", "df58hmr", "df5cgmu", "df5gm8w", "df55oxw"], "text": ["Hello. Pilot here. There are a LOT of inaccurate replies to this post. Let me clear some things up. Concord stopped flying for a huuuuuuge range of reasons. No one factor or reason killed it by itself, but as a combination they mounted up and where eventually too much. I will list the main reasons that killed it off. **1. A tiring airframe** Aircraft have a shelf life of sorts. Unlike a car, an aircraft is exposed to a lot of stresses and strains during its operational lifetime that weaken it's structure and components. Different parts of the aircraft have different life expectancies (The engines being the largest components with the shortest life expectancy) but generally an aircraft lifespan is measured in something called cycles. Depending on the aircraft, one cycle is either one complete startup and shutdown of the engine, or one take off and landing (Regardless of how long the aircraft is actually in the air). An aircraft can only do so many of them before specific maintenance has to be carried out to extend it's life so it can do more cycles. The more it is extended, the more expensive and in depth that maintenance becomes. Eventually there comes a point where it's just not worth it and it has to be retired. Concord was getting close to this point. She was an old aircraft and extending her life further and further would soon have come with complications like shortened flight hours, restrictions of movement/speed and all kinds of things that is undesirable in a commercial aircraft. I will allude to this more later, but many people view the Paris Air France crash as the end of the Concord. It wasn't. Her airframe cycle life would have killed her off a few years later regardless, but we will touch more upon that later. **2. A reluctant maintenance company** Airbus had a contract to maintain the Concord and it was said that they where somewhat reluctant to continue on with it beyond its renewal date. Maintaining the Concord required extremely skilled people and sophisticated facilities only a company like Airbus could bring to the table. When Airbus indicated they did not want to do it any more, that was a big problem that did not really have an immediate solution. **3. A downturn in it's economy** Contrary to popular belief, Concord was always profitable. It can never be said to have been a huge source of profit for BA/AF and it might be fair to say it sometimes was closer to breaking even but it never ran at a loss. The reason for this was economy of scale. It ran on a schedule that allowed it to break even. Concord never flew with empty seats. The price of a ticket was astronomical and that reflected its operating costs. The upside of this was that flying on it was almost a zero wait experience that got you from London to New York in 4 hours 15 minutes once check in time was calculated. There where no queues at the airports or checking in three hours early or anything like that. Minimum check in was 45 minutes before the flight, it had it's own baggage check lines and security for only 160 people. Your time in the airport was kept to an absolute minimum. The downside of this was you couldn't book a flight to fit your dates, you fitted your dates round flying on Concord. An aircraft on the ground that isn't flying and carrying passengers absolutely haemorrhages money for an airline, but in the case of Concord the time spent on the ground was unavoidable so it was factored into the cost of a ticket. That being said, there was a downturn in it's economy that began to pinch into this. As fuel prices and maintenance costs rose, the ticket prices couldn't really begin to keep up, high as they where already and it was predicted its maintenance costs would outstrip what could reasonably be claimed back in it's ticket costs in the near future. This meant at some point, the aircraft WAS going to begin operating at a loss. **4. A loss of confidence and increased safety measures after the crash of an Air France Concord in Paris** Many people like to believe that the loss of the Air France Concord in Paris was the final nail in the coffin for Concord. It wasn't. In fact all other things being equal it would barely have phased BA/AF in terms of worrying about the aircraft's future as the aircraft had a near flawless safety record at that time. At some point in time, every airframe has a crash for some reason. The fact Concord had operated for so long before it's first fatal accident was a testament to the aircraft. However it was just one of the factors that weighed up against the aircraft. A lot of safety measures had to be retrofitted to the aircraft after the crash. It's worth noting though if the crash had been directly to do with a fault in the airframe then Concord would likely have been scrapped there and then. It's no secret in the aviation world that the damage to the engine and resulting fire from the tyre debris striking the fuel tanks did not destroy the Concord. Had it remained on the ground and come to a stop it would likely have been possible to get some or maybe all of the passengers off. Sadly what destroyed the aircraft was that the plane took off before it's take off speed had been achieved and the aircraft basically stalled into the ground. Therefore BA/AF where confident that with the adaptions to the engines and fuel tank strengthening the aircraft would be as safe as it could be. However they where hugely expensive to implement and BA/AF where never fully sure of being able to recoup the costs against a potentially nervous and very small (Due to the cost of a ticket) customer base. Then 9/11 happened which further had a bad ripple effect across the airline industry and Concord unfortunately had to take some of the brunt of that as well (One of the huge impacts was no longer being allowed to visit the cockpit of Concord mid flight which was often a big part of the experience). **5. BA/AF did not want to share their toys** After it was announced that the Concord's would be retired, British Airways and Air France had a multitude of offers from several aviation companies to take or buy the aircraft and continue flying them. One of the most likely offers was from Virgin Atlantic. However Richard Branson did not believe he should have to buy them after they where basically gifted to BA/AF by the French and British governments. As it turns out BA where not willing to continue operating them but they sure as hell wheren't going to let anyone else have the prestige of operating them, and as they legally owned them, they said no. It was entirely feasible they could have had a few more years in them, but BA did not want them appearing in someone elses livery. Hopefully this clears up the main reasons why Concord stopped flying. It was a shame she stopped flying when she did but make no mistake, her time was coming to an end regardless of any crashes. --- Follow up comment with answers to some questions I have been asked as this post is too long. URL_0", "For two reasons. Firstly, was the France disaster, where a Concord took off, suffered some major malfunction, and wound up upside down on the ground, with everyone onboard dead. While it was a genuinely magnificent plane (and I did get the chance to see one arrive at my local airport once, when I was a kid), such a well-publicized disaster occurring to one of the very few Concords in the world (iirc, there were only 12 in commercial operation) killed the brand stone-dead. Work was done go recover things. After years of investigation and reengineering, Concord was prepared and readied to fly once again. A press event was arranged, and a crew of press, enthusiasts, and airline senior bods were assembled for a flight from London to New York, which they hoped would reestablish the Concord as the premier choice for those who wanted fast, luxury travel. The flight was successful, the landing event for the press went exactly to plan, and everything seemed poised for success. And then, just thirty minutes later, the first plane hit the World Trade Centre. Concord's return was overshadowed by about the single worst thing that could possibly overshadow it. The aviation industry took a long time to recover from those attacks. Concord's relaunch didn't stand a chance, and was given up on in mid 2002.", "The Concorde was never a financial success. It cost as much as a 747 to operate, with a third of the passengers. And when you figure all the non-flight time involved in door-to-door travel across the Atlantic, it wasn't that much faster, you are still going to waste most of your day in transit. Finally, because of the sonic booms, it could only travel at full speed over the ocean. Then in 2000, Air France flight 4950 hit some debris on the runway during takeoff, ruptured a fuel tank, and wound up crashing into a hotel. Over 100 people died. The Concorde was grounded for a while, and by the time it returned to service, 9/11 happened, result in a decrease in air travel. The airplane was also badly outdated and due for a major upgrade. British Airways and Air France instead decided to pull the plug at that point.", "On top of what other people have been saying, the relative time advantage of a faster flight disappeared. Let's say the flight is 3 hours vs 6 hours. That's twice as fast, that's a big deal. You could easily wake up in the morning, fly to Europe for an afternoon meeting, and fly back home in time for dinner with your family. Indeed, this is how they originally pitched it. Over the years, airports have become busier, security has become tighter. You can't just hop on a plane anymore. You need to show up for your flight a couple hours in advance. Factor in the extra time you spend getting to/from the airport because a lot more people fly these days. Pretty quickly, the whole advantage of having a flight that's faster starts to disappear. Even if you had the Concord available today, you couldn't really fly to Europe for your meeting and get back the same day anymore.", "basically, it was too inefficient. everything about it was just to make it go faster. the only reason it ever flew was because back then, people were willing to pay for that. with a full tank, it could barely fly from the uk to the east coast. compared to a 747 or an a380, which can go double the distance with the same amount of fuel and carry 4-5 times as many passengers, airlines just weren't able to make enough profits to keep it flying, which is why they took it out of business. I'm not really great at explaining things quickly, but hopefully you get the idea:) p.s. my dad also told me a few years ago that it was because it was a very uncomfortable aircraft. he asked me \"would you rather spend an hour in a really cramped, uncomfortable aircraft, or two hours in a plane with lots of space where you can also get work done while you're at it?\"", "A new Boeing 787 which is one of the most efficient commercial planes has an mpg per passenger of about 104. The concord had 14.", "Wendover Productions YouTube channel has some good videos on the airline industry. They did one on the [Concorde] ( URL_0 ) failure. Plane was really expensive to operate because it had horrible fuel efficiency. It also could only seat about 1/3 as many passengers as a typical transatlantic flight so tickets were very expensive for what was basically just a coach seat. Those who could afford it, opted to pay the same price for a luxurious first class seat on a slower flight.", "Vox has a really cool video about the Concord: URL_0 Its only about 10 minutes and really well edited. It pretty much tells you everything the other responses have explained but just in case you want something pretty to look at :)", "I did a report on this is in college and it had a large part do to the safety concerns after the crash. Which was the only one to ever occur. But one reason I found was that it was too loud. NASA did a study on how the vibrations were very disruptive to the surrounding areas. One of the biggest problems was the economical cost of the plane, it what decommissioned because it wasn't marking much money, this was due to the fears of flying after 9/11. Many less people were flying so they didn't have the seats to fill required for them to make a profit. TL:DR- 9/11 a lot of people weren't flying. Sorry about the format I'm on mobile.", "When the Concorde first flew in the 70s it was more or less the same seating as upper class in other slower planes so it was actually quite nice for business executives to fly over the Atlantic ocean in less then half the time. But it was still really expensive, far more than the regular price, to fly and the Atlantic crossing was basically the only route it could fly with some advantages because it couldn't fly supersonic overland, didn't have the long range such as the 747 and the time margins for short flights are so small it wouldn't warrant the price tag anyway. With the advent of much more luxurious regular and first class seating in 'normal' planes during the late 80s and 90s even those executives who could even afford the Concorde flights would decide to rather fly 8 hours in what is essentially a bed with tv instead of 3 hours in 'economy' seats. The only ever reason for people to fly Concorde where out of pure curiosity and for the time saved and people decided it wasn't worth the time anymore because you could fly much more comfortably. Also, one day travel time to anywhere on the planet was accepted as you spend an hour at the airport anyways. By the late 90s many of those 100 seat aircraft flew half empty when the airline needed them to be almost full to make money and those passengers often just used saved up miles to fly it out of curiosity. Add to that the 2000 crash killing all passengers, even more increased airport time post 9/11, besides the fact that the first flight after the accident was actually on 9/11 and you understand why the Concorde was retired", "Additional - Concorde was very unpopular because IT WAS SO FREAKIN LOUD!!! URL_0 Like miles away from London Heathrow you would hear it, people complained about it all the time, and with noise regs. etc. tightening up, didnt help.", "I asked a pilot this and one of the reasons was because they lost a significant portion of their frequent flier clients in the September 11th attacks. [Here]( URL_0 ) is an article that cites the claim", "The short answer it is the crash of Air France Flight 4590 and 9/11. The reality is the Concord program was essentially NEVER profitable, not when R & D is thrown in. Air France & British Airways kept the tiny fleet of 12 planes in the air basically as a lost leader advertising their brand and a fair amount of corporate ego. But the double-whammy of the crash plus the plummet in air travel following the WTC attacks killed the the program. It would have have cost both airlines millions each *month* to keep the planes going.", "Also relevant. It could only be used for trans Atlantic flight due to the Sonic boom. So the market for its use was pretty limited.", "So [this]( URL_0 ) is a really great video that covers exactly what you're asking! TLDW, Concorde planes did fly much faster, but because of the extra fuel demands of their engines, they were extremely expensive to operate. Their cabins were also small and cramped, so clients ended up choosing business class on the longer flight that at least had the ability to extend into a bed so they could get some sleep at a cheaper price. Airlines were also changing their business model during this time to attract middle class families instead of businessmen, so the cost ended up being the biggest factor in choosing a flight. Most people didn't have the money, so Concorde flights were flying with less than half the cabin full of paying customers.", "[This video]( URL_0 ) pretty much sums it up. Also talks about planes speed in general.", "I lived in Bergen Beach, NY, an area in Brooklyn that is right under the concord's approach path to JFK. She always announced herself when she was coming in over us.", "As well as the excellent points raised here, there was another issue. The Concorde was essentially hand-built with 1960s technology. There was a limited (and reducing) stock of spare parts available to keep them flying and a limited (and aging) group of mechanics who knew how to maintain them. Both British Airways and Air France knew that they couldn't keep Concorde flying forever and there were strong rumours that BA at least was seriously looking at shutting down Concorde operations even before the Air France crash. That just sealed the deal."], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/60aej7/eli5_why_did_the_concord_stop_flying/df61yqp/"], [], [], [], [], [], ["https://youtu.be/n1QEj09Pe6k"], ["https://youtu.be/a_wuykzfFzE"], [], [], ["https://www.youtube.com/watch?v=N-xMOOEngJw"], ["http://www.telegraph.co.uk/comment/personal-view/3597978/How-Concorde-finally-fell-victim-to-the-bean-counters.html"], [], [], ["https://youtu.be/n1QEj09Pe6k"], ["https://youtu.be/n1QEj09Pe6k"], [], []], "score": [1303, 1135, 473, 116, 97, 67, 59, 24, 14, 12, 11, 8, 6, 5, 4, 3, 3, 3]}}, {"q_id": "60ahgf", "category": "Repost", "title": "Despite both being highly totalitarian, how are Nazi Germany and Soviet Russia polar opposites in political ideology?", "title_urls": {"url": []}, "selftext": "Nazi Germany was far-right and Soviet Russia was far-left. Despite this, both were highly oppressive, totalitarian dictatorships. What made their ideologies so unable to get along with?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["df4zzhs", "df4v88q", "df4t9c5", "df563rl"], "text": ["Nazism was a nationalist movement, meaning that they were all about the (mythic, idealized) German people and German state. They were all about taking care of the German people first (and, obviously, horrible anti-Semitism and racism and so on) because they believed that Germany in particular was better than everybody else. Meanwhile, the ultimate goal of Communism is a stateless society where the working class owns the factories and stuff and there's no need for top-down control. In this philosophy, the Soviet Union was actually an intermediate stage-- basically, \"we're going to control everything until you guys realize how great Communism is and rise up to overthrow all the other governments.\" (Obviously the USSR in practice would probably not have given up control at some future point, but that was the justification for its totalitarian governance.) So Nazism says \"GERMANY IS THE BEST NATION AND THE GERMAN PEOPLE ARE THE BEST\" and Communism says \"NO MORE NATIONS, ALL PEOPLE ARE EQUAL.\" Boom, ideological clash.", "In both ideologies, the problematic elements arise from the notion that the group is superior to the individual. In classic Enlightenment philosophy, the group exists only to serve the needs of the individual within that group. Thus the group's actions must be morally reflective of the individuals within that group. In contrast, Nazism and Communism claim the group itself is paramount and the individual must be subordinate to it - and the only morality is the needs of the group. As a result, both doctrines tend to reject all moral restraint so long as it can be argued that the group benefits. However, they differ in terms of how they define the group. With Communism, your group is an ideology. Communism is based on the notion that Marxism is a scientific doctrine explaining all of history, economics and politics. Anyone who doesn't accept this doctrine is clearly wrong and must be educated/exploited/eliminated. However, as long as someone accepts your doctrine, they can be a member of the group. This is roughly similar to how Islam spread - you conquer people and make their lives miserable until they convert to Islam. In contrast, Nazis viewed the group as ethnic/racial group. Their scientific basis was eugenics, where inferior races should either be subordinate to superior races or eliminated entirely. Since you can't educate away racial inferiority, that really means your only solution is to exploit them for labor until you can rid the world of them. These different categorizations of the 'in-group' meant that Nazis and Communists couldn't really get along.", "Nazi ideology was not merely at odds with Soviet ideology; it was created in direct and hateful opposition to Marxism and all Slavic people (which includes most of the Soviet population.) Hitler spoke of Marxism and Judaism as the world's two evils, considered Slavs to be barely human and Soviet Communists to be puppets of powerful Jews, and spoke of a need for Germany to expand east and displace/destroy them. Promptly after taking power, he began to suppress Communism in Germany and issue anti-Soviet propaganda. He overtly hated the Soviets and wasn't subtle about it. As for the Soviets, they had some interest in closer ties, but until 1939 their top-ranking diplomat was Jewish and therefore rejected by Nazi leadership.", "I feel like everyone isn't getting it. From a purely ideological standpoint, Naziism and communism are complete opposites. From a \"apply ideals to real life\" standpoint they are the same because the human element is the same literally everywhere you go. **Eli5 of difference:** Communists view everyone as equal - socially as well as economically. Nazis view one group as absolutely superior to others. If those two ideas aren't opposites then I don't know what is. Also do try to remember that communism sprang from Marxism. Karl Marx was a German Jew. Hitler hated Jews, remember?"], "text_urls": [[], [], [], []], "score": [50, 23, 16, 15]}}, {"q_id": "60bnon", "category": "Repost", "title": "Why can't we build a type of plane that can fly out of the atmosphere and into outer space instead of using rockets?", "title_urls": {"url": []}, "selftext": "I understand the space shuttle is kind of like that but why do we not have something that can take off, go into space, and come back and land no problem all on its own? I feel like using rockets to get shit into orbit is a little Overkill and primitive. For instance the sr71 Blackbird reached the edge of Earths atmosphere why couldn't it just keep going until it is in orbit?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["df50nm6", "df50s7w", "df51bmz"], "text": ["Planes fly by forcing air over their wings to create lift. They use engines to make the plane go forward and the forward speed causes the air to push up on the wings which counteracts gravity. There is not any air in space. So wings are useless. The only way to make yourself go forward is to throw a bunch of stuff away behind you. Which is what a rocket does.", "Jet engines require oxygen to combust with fuel and air flowing around the wings to create lift. In the upper atmosphere you run out of both of those things and so the plane simply cannot climb any higher. Now, you could still escape gravity with a rocket, but then you can just build a rocket - like the one the space shuttle is strapped to on takeoff.", "As you go up, air pressure goes down. This means air-breathing engines lose their oxidizer, and you have nothing for the wings to lift up against. Some kinds of specialized super-aircraft such as the SR-71 that compensate for this by going extremely fast. There are potentially faster technologies such as [scramjets]( URL_0 ), but even as incredible as these could be, even at their fastest they can only reach half orbital speed. The rest of that speed can only be reached by rockets right now. Because that speed needs rockets, and rockets needs fuel, this means any scramjet plane or whatever needs to bring all that fuel with it all the way up. This makes designing such a plane awkward and very heavy. For example, the [Skylon project]( URL_1 ). Skylon short-circuits the problem by having engines which can switch between air-breathing and being pure rockets, but it will be a long time yet until such complex engines are working."], "text_urls": [[], [], ["https://en.wikipedia.org/wiki/Scramjet", "https://en.wikipedia.org/wiki/Skylon_(spacecraft)"]], "score": [17, 6, 4]}}, {"q_id": "60g3eb", "category": "Repost", "title": "Why fabrics go dark when they get wet", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["df63l99"], "text": ["Darker means there's less light reflected. Reflection occurs when light goes from one refractive index to another. As an example, air and glass have different indices, so you will see some reflection in a window. The bigger the difference in refractive indices, the more reflection there is. So when light goes from the air to the fabric, there's a big difference between the indices, so lots of reflection. Now add water. There's now a layer of water between the air and the fabric. Water has a refractive index between that of the fabric and the air, so there's less reflection. To break this down, when light reached the air/water boundary, the difference in indices is lower, so less reflection. Then when it meets the water/fabric the difference is again lower, so less reflection."], "text_urls": [[]], "score": [6]}}, {"q_id": "60g86e", "category": "Repost", "title": "the concept of the dark web. I understand that you need certain software etc, but is it like the regular net? Do you just type in wed adresses, and is there a dark google or something? [Other]", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["df64dd5"], "text": ["The dark web refers to anything that can not be gotten to by any common web search engine. This includes a lot of networks that is not connected to the regular Internet such as banking networks, government networks, medical networks, military networks, private home networks, etc. There is also a lot of big sites with not much interesting in them that the search engines do not bother indexing. There are tons of wikipedia clones out there that is just skipped by the search indexers. And what about URL_0 with its huge data storage that itself contain more data then is available on the rest of the \"white\" web? And then there is private storage hosting services like Dropbox and Google Drive. Everything is available on the Internet but not in a public fashion. This also include your private facebook images and your reddit DM messages. So the dark web is huge and contains a lot of things that is not easily available for a good reason. There is some sites that are hidden to avoid prosecution as their content would be illegal. Of course the common web search engines do not index these. One popular way to hide your identity is Tor Onion Router which is a project to help people stay anonymous online which is helping oppressed people around the world including in China, Libya and Russia. Of course they can not distinguish between people using the service for planning demonstrations against their oppressive governments and people who want to score some weed or even child prostitution. If you have a web site hosted on Tor you get a randomly chosen web address in the .onion domain. There is no search engine for it and it only composes a tiny portion of the dark web but this is where you usually find those websites that the creators do not want you to find."], "text_urls": [["archive.org"]], "score": [3]}}, {"q_id": "60gau1", "category": "Repost", "title": "What is the physiological reason behind being \"hangry,\" and why does it seem to affect women more than men?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["df64dln"], "text": ["I have to carry around a secret stash of snacks for when my girlfriend starts snapping at me."], "text_urls": [[]], "score": [5]}}, {"q_id": "60gqv3", "category": "Repost", "title": "Does the NASA EM drive work? If so, how does it work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["df6a4rr"], "text": ["No one has proved it to work and no one has disproved it to work. The reported thrust could be explained by noise interference or the microwaves interacting with something on the quantum scale. We don't know, and the majority of the scientific community think it doesn't work because based on our understanding of science it really shouldn't work."], "text_urls": [[]], "score": [3]}}, {"q_id": "60ixnv", "category": "Repost", "title": "National debt", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["df6r5qi"], "text": ["> I feel like if 82% of the work I did equated to debt I owed, I would be really struggling!? National debt and personal debt isn't the same. And *many* people have way more than 100% debt. When you get a mortgage, you're likely borrowing WAY more than 100% of your yearly income, especially if you're in a high cost of living area. Shit, even financing a new car can easily throw you over 50% debt. Countries borrow money to spend money, and as long as the return on that spending is higher than the interest, it's worth it."], "text_urls": [[]], "score": [3]}}, {"q_id": "60jbyg", "category": "Repost", "title": "why do the majority of cartoon characters only have 4 fingers?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["df6u6eq", "df6vaa9"], "text": ["Drawing hands are HARD. If you try to draw a hand and it's not perfect, it looks SO WRONG and distracting to people. Instead, they don't even try. Hell, they try hard to make the hands look fake (wrong number of fingers). This way it's so wrong it doesn't annoy people. It's like when robots are made to look as realistic as possible, but they just end up looking weird and creepy. But robot-looking computer bots made of metal look fine to us; they're so far away from looking like a person, we don't compare them to real people.", "With many cartoons, all the features are simplified. Eyes become dots, hair becomes a few squiggles, etc. It would be incongruous for a character to have a simple face and very detailed hands, so losing fingers is one way to reduce detail. Unless you are looking, close, 4 and 5 fingers look about the same, while at three, you start getting crab people. Another way to do this is to draw mitten hands."], "text_urls": [[], []], "score": [16, 7]}}, {"q_id": "60k2zz", "category": "Repost", "title": "Net neutrality", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["df73br3"], "text": ["Net Neutrality is the idea that all Internet traffic should have the same priority regardless of content. Its an unspoken agreement that ISPs wont throttle content from competitors while boosting content from their own sources. Comcast throttling Netflix to extort money is a prime example of the douchebaggery that Net Neutrality is meant to prevent."], "text_urls": [[]], "score": [4]}}, {"q_id": "60mib5", "category": "Repost", "title": "Why is it important not to fall unconscious after you suffer a concussion?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["df7kdm5", "df7pf88", "df7oefc", "df7r77s", "df7l14o", "df7l4h7", "df7rky1", "df7pg9x", "df7y8re", "df7p8bl", "df7tw6f", "df7rs4d", "df7udim", "df88ogc", "df7w0yu", "df814r8", "df8fe3y"], "text": ["It has nothing to do with consciousness affecting your recovery. It's all about them being able to ask you questions and observe your responses. If you're awake with your eyes open they can tell if your pupils dilate properly or if your speech is slurred or if you're even aware of your surroundings. These are all important tests to see how severe your concussion is. Without that, the only option is a brainscan.", "Emergency doctor here (work in ED / A & E / ER depending on your locality). Just to add on a little to the previous answers which are mostly correct that, in short, it's not actually important to keep someone awake after a head injury. Everyone, especially children, can become quite sleepy after a good enough blow to the head. That, in itself, isn't a cause for concern. But we are looking at how rousable you are from that sleepiness amongst a list of other \"red flag\" symptoms and signs (such as vomiting or the more obviously neurological signs such as weakness or seizures). If, after a couple of hours, your natural state is still to drift off to sleep shortly after being roused - you've just earned yourself a CT head to look for signs of a significant head injury (e.g., bleeds). But if you were so sleepy that it took a reasonable amount of painful stimulus to wake you up then there would be no waiting and you'd be getting scanned straight away. So, again in summary, there's no benefit to remaining awake after a head injury - you won't suddenly drift in a coma because you wanted to rest your eyes for a moment... Instead, it's how easily you're woken or how long that sleepiness lasts for after the head injury that matters. Edit: I need to address one of my bugbears (... where on earth does that phrase come from?) which is in the current top answer: Pupil reflexes. If you have uneven pupils due to the effects of a head injury **you will not be conscious!** The cause of unilateral dilated pupils, in the context of head injury, is due to there being a significant enough rise in intracranial pressure - due to the presence of blood within the head - that it causes a 3rd nerve palsy. The other softer signs of significant head injury will already be present long before you blow a pupil.", "Medical resident here: the major concern regarding head injuries is the potential presence for an epidural or subdural hematoma (a bleed above or under the dura mater that surrounds the brain). As we prefer not to perform a CT scan on every person who bumps his head, many people are sent home from the emergency department with instructions to have a family member wake the person every 1-4 hours to check his alertness and ability to orient to name, where he/she is, and what month it is. Any new confusion or increased difficulty waking a person up fully can indicate the presence of brain swelling or intracranial bleeds that may require neurosurgical intervention.", "From an EMS standpoint, we don't want you napping on us because we want to be able to monitor your mental state. If your mental state becomes altered (you have trouble speaking, you think you're the President, etc), it gives us an indication that something likely isn't okay in your noggin. When a patient's mental state changes in a bad way, that upgrades your transport to high priority (if it isn't already high). Since EMTs have a limited scope of practice (we don't really have many tools available due to our level of training/certification), and we often don't have the manpower to accurately monitor your vital signs while we're packaging and moving you, keeping you awake and talking allows us to maintain a general idea of how things are doing in your body until we can get you to definitive care (a hospital). It's just one of the tools that we have in our pretty tiny toolbox. Realize that this isn't specific to head injuries---I prefer all of my patients to stay awake for the whole transport. As for what the doctors prefer in the ER, that's well outside of my swim lane.", "My wife works in concussion research and the idea that you needed to keep someone awake after a head injury can actually be detrimental to their recovery. She says that if someone is falling unconscious that you should let them. If you overstimulate their brain with questions poking prodding and lights in their eyes you can only make it worse. The brain needs to rest same as if you injure another put of your body and falling unconscious is your brain's reflexive way of forcing itself to rest.", "I think the myth about *keeping someone with a head injury awake because they might fall into a coma* has been debunked in recent years. They are perfectly fine to let them rest unless you need to keep asking them questions to judge their functions.", "Subdural hematoma patient here. Ex pushed me and I fell. Hit the lower part of my skull (where it meets the spine) pretty hard on the edge of a metal framed glass topped patio table. Thought nothing of it (I've fallen over before on my own drunken accord... I was apparently 25 and indestructible). Two weeks later I'm immobilized in bed with serious migraines. Never had headaches before. Lost 20lbs in two weeks (win). Avoided the hospital for lack of medical coverage. Lost sense of taste. Lost sense of smell. Vision went DOUBLE. Saw two of everything and couldn't walk to my kitchen without banging into walls. Finally decided to go to the ER. Waited 7 hours. Saw dopeheads get meds before I was seen. Once finally admitted, explained symptoms... immediate CT scan. Brain surgery an hour later. Could've died. Still can't smell the scent of shit (yay?) and have limited peripheral vision four years later. Hit your head? Feel funny? SEE A FUCKING DOCTOR. Scariest experience of my life. Head trauma is no joke.", "Please note that it is also important to actually get sleep after a concussion. Sleeping is a critical factor of recovery, and the closer to the incident you can sleep the better. Once you are done being questioned, and once you answer questions every once in a while, do NOT try to stay awake if tired. URL_0", "Emergency medicine resident: most good points have been made, but there are some floridly incorrect points being spread here. Immediately after the injury, I care if you passed out when you hit your head or have amnesia for the 30 minutes prior to the event. This helps me risk stratify who needs a CT scan and who doesn't. This isn't us being frugal; if you CT scan every comer who has minor head trauma, you will eventually cause a tumor. En route, its good to keep assessing you to make sure your status hasn't changed. The classic presentation for an epidural hematoma (blood between the dura, a tight layer against the skull, and the skull) is a \"talk-die\" lesion; i.e. the patient briefly loses conciousnes, rouses and speaks, and then dies of rapid expansion. Once you've been assessed and observed and diagnosed with a concussion (i.e. too low risk to need a CT scan) and sent home, there is no need at all to be woken up. I do not advise my patients to have someone wake them when they are sleeping. I personally use the Canadian CT Head rule to stratify who needs a CT scan. Its been validated to rule out those scary bleeds, described above. You should be given \"return to the ED\" instructions on discharge that cover red flag symptoms. These are usually vomiting more than 2 times, severe pain despite NSAID's, or confusion.", "This is actually a falsehood, in a way. They say that you shouldn't fall asleep if you have a subdural hematoma. Basically, if your brain is bleeding. If your brain is bleeding you can suffer all kinds of adverse effects, up to and including death. If you just have a concussion, it is unwise to stay awake. In fact, sleep is the best thing you can do to heal. Src: Had concussions.", "That is no longer the suggestion for someone who suffered the concussion. We now know that during a concussion, there's a massive energy imbalance, where there's a huge \"surge\" of energy and nurtrients can't get into the cell fast enough for the brain to function like that. The best way to recover quickly is to limit the amount of neurons firing, which is what sleep does. The previous suggestion to them not falling asleep, is that they are worried about a hematoma forming. These hematoma's are what can be deadly, or seriously life altering in cases of concussion. There are two types of hematoma, one is subdural and one is epidural, which just describes what layer they are on (Dura matter is a lining around the brain, inside is the subdural and outside of it is epidural). Subdural is the one they are worried about, because the subdural layer contains the veins rather than arteries, which are on the epidural. Because of the way the veins work rather than the arteries, when a vein is ruptured it bleeds much more slowly, so in order to monitor the symptoms of someone, you need them to be awake (since there really isn't any tell tale signs of the injury when they're sleeping, unless they don't wake up). Epidural/Arterial Hematoma's will form much more quickly and you should see an effect soon after, rather than later that day, or even a few days later. But as everyone else has said, it's all about the ability to monitor symptoms and make sure you don't slip into a coma. It's fine to let someone sleep after a concussion, but the suggestion now is to check on them every half hour to an hour.", "Because the symptoms of more serious problems cannot be observed while the person is not conscious, there may be serious brain damage which isnt obvious at first glance.", "There has been mew information released that is perfectly ok to sleep with a concussion now. Once you do the initial checks like check pupils can dilate. If you are responding ok. Then you can go to sleep as this is when most of the healing occurs.", "You're not supposed to go to sleep before you see a doctor, a concussion will make you sleepy. You could have bleeding on the brain, which could cause you to die. It's fine to sleep after going to the hospital and having your brain scanned and they find no bleeding.", "Cave, extremely simplified answer. The reason why it's advised to regulary rouse kids and adults after head trauma is to make sure they are not getting increasingly somnolent (sleepy to the point of not bein rousable anymore), because that could indicate increaed intracranial pressure, brain bleeds etc., which could lead to death. If you had an uncomplicated concussion, you could sleep all you want - but since we don't know how severe your trauma is, we check. The sleeping afterwards is not what is dangerous, it is that you might miss an altered state of consciousness (think of someone awake who talks to you, then starts slurring speech as time goes by and drifts off, unrousable, to give an extreme example). TL;DR: If someone is sleeping/unconscious, it's harder to tell if the are just resting (yay!) or currently dying (nay!).", "The immediate concern is that you have internal bleeding in your head. Going to sleep could mask blacking out due to pressure on the brain, which could lead to death. After a brain scan, the concern is considerably lower, so you are allowed to go to sleep in a monitored environment (I.e. hospital). They will continue to check on you in case of a slow bleed that had not been immediately evident.", "By all technicality is better for we you to fall asleep if you feel tired. Staying awake actually has the potential to cause brain damage. However (and it's a big one), humans often require the assistance of other humans - particularly when they're injured. Being awake facilitates someone effectively monitoring your condition without needing something like a brain scan (which only a limited number of people can read anyway). Source: related to a Neuro-psychitrist"], "text_urls": [[], [], [], [], [], [], [], ["https://www.cdc.gov/traumaticbraininjury/recovery.html"], [], [], [], [], [], [], [], [], []], "score": [16160, 3608, 288, 209, 170, 99, 91, 35, 24, 21, 17, 9, 4, 4, 4, 3, 3]}}, {"q_id": "60n38g", "category": "Repost", "title": "The Higgs Boson and Higgs field", "title_urls": {"url": []}, "selftext": "I've been trying to read up on them but I don't understand many of the physics words necessary.", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["df7tamo"], "text": ["Basically, quantum field theory says that all particles are just fluctuations in a particle field. Imagine the ocean. Normally it is flat, but if you drop a rock into it it'll form ripples that travel outwards. Particle fields act the same. F.ex the electromagnetic field is usually pretty smooth. But if you poke it hard enough it'll start to ripple. Those ripples look like particles to us, in this specific case photons. Every particle has an associated particle field. So an electron is a disruption in the electron field. An up quark is a disruption in the up quark field etc. So that explains the relation between the Higgs field and the Higgs boson. The Higgs field is just another particle field and the Higgs boson is a disruption in that field. So why is the Higgs boson such a big deal? There are dozens of particles, what makes the Higgs boson so special? The answer to that is mass. What is mass anyway? Mass is just a resistance to acceleration. If I try to push a car it won't instantly zip away at the speed of light, it will slowly start rolling, providing counterforce as long as I try to accelerate it. Einstein has shown us with E=mc^2 that mass is just confined energy. Say I have a massless box lined with perfect mirrors. Say I release a photon in the box. If I now try to push that box the photon will get redshifted on the far side and blueshifted on the near side. Since photons do have momentum, this causes the photon to push harder on the near side than the far side. The box is suddenly pushing against me. The box suddenly acts as if it has mass, while it is entirely made out of massless particles! Turns out that all mass is just an emergent behavior of massless particles interacting with other massless particles. You are a lot like that box of photons: Just a whole load of massless bits interacting to give the illusion of mass. This works very well for every composite particle. The protons and neutrons in atomic nuclei get 99% of their mass from tossing gluons between their constituent quarks. However, there was a problem: That remaining 1%. Certain particles have mass, even if they're all alone and not interacting with anything. For example, electrons have mass, but as far as we're aware they aren't made of any smaller particles. This is where the Higgs field comes in. The idea was that Electrons, quarks and other particles have mass because they're constantly interacting with the Higgs field. They're constantly dumping and stealing something called Weak Hypercharge from the Higgs field, and due to those interactions they have mass. This was theorized back in the 1960's. But theories mean jack shit without evidence. So how do you detect if a particle field exists? By detecting the particle of course. So this is what happened in 2012. They used the LHC to give the Higgs field such a large whack that it produced a Higgs particle. That Higgs particle quickly decayed, but scientists managed to measure the resulting debris, thus showing that the Higgs field is real and explaining why particles have mass."], "text_urls": [[]], "score": [3]}}, {"q_id": "60n59k", "category": "Repost", "title": "How does inbreeding cause so many issues?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["df7oojb"], "text": ["The reason are so called \"recessive genetic disorders\". Those are genetic diseases which only express themselves when you have two copies of the defective gene. If there's only one of them, they may have a reduced effect, no effect at all or even a benefit in some cases. Because of this, it is necessary that both the father and the mother carry the defective gene. So if 1% of all people carry the defective gene, only 1%\\*1%= 0.01% of all couples both carry it, and therefore could have diseased children. 1/4 of their children would suffer from the disease, which is a total of 0.0025% of all children. However, siblings and other closely related people are much more like to have inherited that gene. For example, if one parent has it, each child has a 1/2 chance of carrying the defective gene, so two of them would have a 1/4 chance of both carrying the gene. So the chance of having that same disease among siblings would be 0.25%, 100 times more likely. So in short: Children of closely related parents are far more likely to have one of these recessive genetic diseases, many of which are incredibly rare otherwise."], "text_urls": [[]], "score": [3]}}, {"q_id": "60nb1e", "category": "Repost", "title": "How does something like Alzheimer's lead to death?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["df7pj4i"], "text": ["The disease itself doesn't directly cause death, however it slowly causes the affected person to lose the ability to take care of themselves - they lose motor functions and the ability to speak, and end up spending their days bedridden, which also results in lack of proper diet and weakening of the immune system. They usually die from something like infections caused by pressure ulcers or pneumonia."], "text_urls": [[]], "score": [5]}}, {"q_id": "60obl8", "category": "Repost", "title": "Why do countries around the world have different outlets? Why couldn't we have decided on one before?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["df7xz35", "df7y4jv", "df84do6"], "text": ["I'd like to refer to this XKCD comic: [Link]( URL_0 ) At this point it is too expensive to go through and redo the outlets in different countries, which would lead into breakups of the industries and supply chains that make products internationally.", "> Why couldn't we have decided on one before? Who is we? The United Nations or even the League of Nations before it existed long after Electricity became a thing. Plus even if they had the foresight for it there would be no consensus, the world would probably be split into two or three sockets surrounding the political divides of the time. Different countries have different outlets just because they do, each one came up with their own. Sometimes its practically pointless, the only difference between port and port is shape. Other times, countries will have differing amperage and voltages in their electrical grids, so plugging a device intended for one into the other is a good way to fry the device, so preventing the user from doing so until they get an adapter is a good thing.", "Electricity predated portable devices and inexpensive travel. It didn't matter if the outlet in the UK and the US were different, because few people traveled, and those that did weren't bringing their 100 lb. radio cabinets with them. By the time more people were travelling with more devices, the different outlet types were too entrenched to change."], "text_urls": [["https://xkcd.com/927/"], [], []], "score": [5, 5, 3]}}, {"q_id": "60r6cq", "category": "Repost", "title": "How is the chip on a credit card more secure than the magnetic strip on the back?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["df8muf5", "df8mehf", "df8u3s4"], "text": ["The mag strip is just the card information on the front stored in a magnetic medium for quick machine reading (swiping it just tells the reader card number, name, expiration, etc). OTOH the chip reader queries the chip with a challenge string which the chip encodes using a secret algorithm and sends back to the reader that forwards it to the bank system to verify.", "[insert repost flair] The chip is designed to be much more difficult to clone, as it does not expose a static output. In order for a transaction to take place, the reader must establish two-way communication with the chip.", "The chip is a miniature computer. There is a permanent storage, there is a CPU, there is a RAM memory to run a small application. When the chip is programmed at the factory, a public key of the bank is stored in the chip. This allows to perform [public-key cryptography]( URL_0 ). The chip knows it's communicating with the bank who issued this chip, and the bank knows it's communicating with authentic chip issued by them. The communication between them is encrypted. Reading storage on the chip is extremely difficult because the storage elements are just a few hundred atoms big (maybe even tens of atoms these days). You will probably need to spend tens of millions dollars to create a reading device (so that you can clone it). Compared to the chip magnetic stripe is a joke. You can get a stripe reader for a few hundreds of dollars and copy the information to a blank card."], "text_urls": [[], [], ["https://simple.wikipedia.org/wiki/Public-key_cryptography"]], "score": [10, 3, 3]}}, {"q_id": "60rtlq", "category": "Repost", "title": "What happens when you get knocked out?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["df8t3fa"], "text": ["The trauma from the brain bouncing around your skull basically overloads the neurotransmitters in your brain, making you go into a short-term paralysis. You then lose consciousness and your muscles relax. This isn't going into internal bleeding and many other things that can happen that can kill you."], "text_urls": [[]], "score": [7]}}, {"q_id": "60svz7", "category": "Repost", "title": "If a camera lens is a circle, then why is the picture a rectangle?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["df91iie"], "text": ["The lens is a circle but bends light so that it hits a rectangular sensor (digital) or rectangular film in the desired way"], "text_urls": [[]], "score": [3]}}, {"q_id": "60vedh", "category": "Repost", "title": "How do scientists know that planets so many light years away, that are only blurs on our telescopes, have water and other such elements on them?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["df9mijo", "df9jok7", "dfa95nm"], "text": ["It's called spectroscopy. Simply put, when light go through an element like hydrogen, the atoms will absorb different wavelength of the light. When you analyse the spectrum of light that when through hydrogen you will see a couple of black line where the wavelength were absorbed. It's a bit like the fingerprint of the element. URL_0 Here a few example of the ''finger print'' of different element. So if you look at the light from a star, that light was produce in the core of the star and had to go through the star atmosphere before reach us. So we can see which ''finger print'' of element we see in the spectrum and determine which element there is in the atmopshere of the star and what percentage of each there is. For a planet, the light emitted by their star went through their atmopshere, bounced on the ground, went through the atmosphere again and then reached us. So we can see what elements that light went through.", "They looked at a spectrum of light and saw water absorption lines. URL_0", "the netflix show cosmos goes over this too. i recommend everyone watch it. basically explains a bunch of science and what not."], "text_urls": [["https://image.slidesharecdn.com/stars-100913132254-phpapp01/95/stars-4-728.jpg?cb=1320914863"], ["https://phys.org/news/2017-02-atmosphere-hot-jupiter-exoplanet-pegasi.html"], []], "score": [24, 7, 3]}}, {"q_id": "60z6b0", "category": "Repost", "title": "What exactly is clean coal?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfahbcn", "dfah40t"], "text": ["The term \"clean coal\" is a myth brought about by the coal industry's public relations team and really the correct term is coal pollution mitigation. There is no such thing as clean coal. Coal is the dirtiest of the energy production fuels and there is no way to really use coal in a clean fashion, but there are ways to mitigate the pollution. However, all methods essentially swap one pollutant for another pollutant so the trade off is marginal. There are a number of different methods, but none of them have proven to either be successful for large scale use or they are just so expensive that they are economically unfeasible. Do date, no \"clean coal\" energy source is in use. Clean coal is an oxymoron that is purely sold to the public for political purposes.", "Coal burning that uses special converters to make the byproduct less harmful for the environment but still more harmful then most other energy sources. URL_0"], "text_urls": [[], ["http://www.yaleclimateconnections.org/2010/03/clean-dirty-clean-coal/"]], "score": [8, 4]}}, {"q_id": "60z6qk", "category": "Repost", "title": "Why can some people feel storms approaching in their hips, knees or other joints?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfajjur", "dfai1p7"], "text": ["The air in our atmosphere is constantly pushing down on us, although this pressure does vary all the time. This is called barometric pressure. Low pressure in the atmosphere tends to have storms that come with them ( why that is, is meteorological and some one could expand on that). When low pressure \"fronts\" come ( and the storm) the pressure against your body drops as well, and your joints and areas that are injured or are old can begin to swell/ inflamed and \"ache\". I broke my tibia (lower leg bone) from a motorcycle accident and my knee from the accident tends to act up when storms come. Just like anything else in life it's not a 100% accurate measurement though. Edit: spelling and grammer.", "I want to add to your question. I can feel storms coming in some joints but only the ones I've broken. What makes the broken and healed joints different than the ones that have never been broken"], "text_urls": [[], []], "score": [4, 3]}}, {"q_id": "60zi2l", "category": "Repost", "title": "What are the bright dots you see sometimes when rubbing your eyes?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfal8yc"], "text": ["It is called phosphene. it is an illusion that is caused by manually stimulating the cells of the eye. For more checkout this Wikipedia article URL_0"], "text_urls": [["https://en.m.wikipedia.org/wiki/Phosphene"]], "score": [3]}}, {"q_id": "612fuh", "category": "Repost", "title": "Why do we see colours when we push our eyes?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfb6cto", "dfb923h"], "text": ["The receptors in your eyes are normally stimulated by light, but that's not the only thing that can stimulate them. Electrical activity and pressure, for instance, can also do so. So when you push on your eyes, you exert pressure against those receptors, which causes them to send signals to the brain. The brain is ignorant of the *cause* of the stimulation, it just says \"Hey I got information from the color guys\" and so it paints you a picture based on the signals.", "Could someone apply a pattern of pressure to create distinct images?"], "text_urls": [[], []], "score": [36, 12]}}, {"q_id": "613380", "category": "Repost", "title": "What Happens on a Molecular Level When Two Things Touch?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfbb8nm"], "text": ["The atoms of your finger have electrons around their nucleus. When you push down on a keyboard key with your fingertip, then electrons in the tip of your finger get really close to the electrons in the plastic atoms on the top of the key. Since electrons repel each other, eventually your electrons are pushing away the key's electrons enough that the key moves. That's how you type. I call that contact, but it's not exactly the same."], "text_urls": [[]], "score": [3]}}, {"q_id": "6145x5", "category": "Repost", "title": "Space Time.", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfbmcoa"], "text": ["Up until Einstein people followed **Newton**s concept of an \"absolute time\". This means while there might be different timezones (since we just arbitrarily set them a couple of hundred years ago), one hour for you would have the same lenght as one hour for me, **independent** of where we are or how fast we move (or anything else). What **Einstein realized** was that **time and space are** actually not separate concepts but **linked**, this is what we call spacetime and is at the center of the theory of relativity. In most cases the reciprocal influence between what we call space and time is small, which is why we get away with ignoring it in our day-to-day-lives (unless you are an astronomer or work with GPS or so). It's like saying the surface of a lake or sea is flat - while we know that the earth is round and it thus has a tiny tiny curvature, but this curvature won't matter much to you (or me). When you move faster (close to the speed of light) or are near really, really heavy objects (black holes for example) the interactions between space and time however become larger and larger. This all starts being a (tiny) bit more intuitive if you think of time as just another dimension (in addition to the 3 spatial ones) and then use \"standard matrix calculus\" to transform coordinates from one reference system to another (but for this to really apply to someone that person needs to have an understanding of maths at a college/university level, so not exactly ELI5) **Highly simplified:** - being near large masses makes you age faster (astronauts age about 0.01 second per year less than people on earth) - moving faster makes you age slower (flying in planes around the world makes you age about the fifth millionth part of a second less....so not really worth it) - the thing that \"connects\" space and time is the speed of light (c) which is the upper limit for the speed anything can achieve, independent of reference system. This means that - counterintuitive, I know - if you send out 2 lightbeams into opposite directions and then \"look\" from one of the beams at the other (make it your reference system), it will still only move away from you with the speed of light (and not twice as fast). - This is also kind of the reason the equation E = mc\u00b2 is so famous, as it illustrates that connection. PS: I'm a physics graduate, but I fear my professors would probably murder me for butchering the concepts like this. still, general idea should be fine and I hope somewhat understandable. edit: formating/highlighting"], "text_urls": [[]], "score": [4]}}, {"q_id": "617d3d", "category": "Repost", "title": "Why were prehistoric creatures so much larger than creatures of today?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfcb5y8"], "text": ["There are a couple of theories. In the Paleozoic Era, there seems to have been more oxygen in the air which allowed for massive insects. Being larger also can have evolutionary advantages. Larger animals are harder to predate. But as a result, the predators also grow bigger. A third theory is that shifts in temperature has some effect on size, as temperature has an effect on metabolism."], "text_urls": [[]], "score": [3]}}, {"q_id": "617nu8", "category": "Repost", "title": "How a conventional battery stores power.", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfcdtoh", "dfceirq"], "text": ["Technically the batteries don't store electricity, if you pull them apart you won't find it, they produce it as the result of chemical reaction happening in them. It doesn't release all at once because chemical reaction happen relatively slowly. Capacitors are the things that can store electricity and can release it at once. In non-rechargeable batteries the reaction happens once, and once it's out of reagents it produces nothing more, in rechargeable batteries the reaction can be reversed through electrolysis if you add electricity to it.", "*TL;DR:* **Because nature allows us to change one form of energy into others, batteries allow us to store electrical energy in the form of certain chemicals, and we can cause those chemicals to convert that energy back into electricity in a controlled way.** Electricity is a form of energy, kind of like heat and light are forms of energy. All of those things can be stored up in certain chemicals. A great example is a tree: when it grows, it \"stores up\" chemical energy by turning sunlight and water and air into wood. We can then burn the wood from that tree, and it releases that chemical energy, a whole lot faster, in the form of heat and light. But it doesn't *instantly* release 100% of that energy, the process takes time because the chemicals take time to meet and react to each other since wood chunks are very large and not every bit of them is exposed to lots and lots of air. Batteries, pretty much the same thing, but they are built to convert their chemicals to electricity instead, and you can then convert that electrical energy into heat, light or movement depending on how you apply it. Batteries store up that chemical energy in two ways. The first way allows for a lot of energy storage but unfortunately is a one-way process - once it's drained, you can't feed energy back in and recreate the battery's original chemistry, kind of like how burning wood makes that wood go away. The second way allows you to feed energy back in and create the battery's original chemistry. This requires more engineering and is tougher to build though, so rechargeable batteries are more expensive. And in the same way the wood doesn't just explode into energy instantly, the battery's construction regulates the speed at which it converts the chemical energy inside it into electricity."], "text_urls": [[], []], "score": [6, 3]}}, {"q_id": "618qhj", "category": "Repost", "title": "Why are galaxies relatively flat as opposed to being spherical?", "title_urls": {"url": []}, "selftext": "I took a look at [this post]( URL_0 ) and noticed every galaxy I see are always generally flat and not spherical, why is that? Please remember I'm 5. Edit : front page? ok", "selftext_urls": {"url": ["https://g.redditmedia.com/WD31u97UFUWUarQJtWkX1sdqewJ7iS2Zjt3fe5Ze6K8.gif?fm=mp4&amp;mp4-fragmented=false&amp;s=edc7f53ee8330194e6f1d8bc9d440b0e"]}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfclo41", "dfcsav5", "dfctttn", "dfd437x", "dfcup32", "dfcjdto", "dfcl8si", "dfctgf1", "dfd851m", "dfcuf73", "dfckfgu", "dfd4c84", "dfdgg5i", "dfdo7fn", "dfd9vdn"], "text": ["From [Previous thread]( URL_0 ) - Here is a great ELI5 explanation. > Have you ever seen pizza made from scratch? The dough begins as a ball. It is then thrown in the air and spun. As it spins, the dough flattens and moves outwards into a disc shape. Solar systems and galaxies form like that. > Because they spin. When you have loosely connected matter, like the dust from which galaxies are formed--or, say, pizza dough--as it rotates, it tends to push material away from the axis of rotation. Thus, gravity can compress the matter into a disc-like shape, but the faster it rotates, the harder it is for it to compress into a spherical shape. > This applies to the formation of many objects in astrophysics--it's why solar systems tend to have a 'plane' much like galaxies, and even stars are originally formed from a collapsing disk. > It's also worth noting that there are more spherical galaxies, as well as a large central bulge in otherwise 'flat' galaxies. There's quite a lot of variance.", "As kind of an addendum to this question, is it possible for a disc shaped planet or star to exist? Or is it not possible for one to spin fast enough to achieve the effect? Is a pulsar the closest you can get to this?", "If you have a large clump of particles swirling around randomly, there is generally a direction of rotation that the whole clump is spinning in. As for why its flat; generally, while the whole is spinning, the up and down motion tends to cancel out as particles crash into each other with the spin persisting. The result is a spinning flat disk that many galaxies this video describes it better than i ever could URL_0", "So the main thing at work here is conservation of angular momentum, which is a fancy way of saying that the total amount of rotation in a closed (isolated, not connected to some other source or sink of energy) system has to stay the same. So say you have a huge cloud of dust that will one day be a galaxy. At the moment it's a huge blob with particles flying in all directions and bumping into each other. If you add up the trajectories of all of the particles in that cloud, you will end up with a net amount of rotation on one axis (in 3D space), which means that the whole cloud is rotating in some direction on some 2D plane. Since the total amount of angular momentum in an isolated system has to stay the same, that means that the cloud must rotate no matter how the forces inside it end up balancing out. Particles that aren't rotating in that direction continue to bump into each other, as well as rotating particles, and over time, all of those opposing directional forces cancel out, leaving the cloud more or less all rotating in the same direction, on that same flat plane. The reason the disc doesn't collapse into a sphere is because the particles are individually too light relative to their distance between each other to overcome the centripetal forces keeping them locked in their orbits. Planets form spheres rather than discs because the particles that make them up, while starting as a cloud and collapsing into a disc, are able to pull together into clumps gravitationally. They still keep rotating in the same direction, but they all become larger chunks with enough mass to maintain a 3D shape against the speed of their rotation. This is also why all of the planets in most solar systems orbit in the same direction, because all of the particles that made them did so as well, and had nowhere to dump that rotation.", "Actually most galaxies aren't flat. The ones you know like andromeda and our own milky way, have a disk where most of the stars, planets, dust etc is but theres also a halo or sphere/oval shaped area around these galaxies which have less tightly packed dust, stars, star clusters, and planets. Theres also alot of rogue objects which arent really bound to anything gravitationally and are just drifting. The halo isn't really visible but there are objects that are a part of the galaxy out there. Then there are other types of galaxies which some don't even have a defined shape. Source: studied astronomy in college", "If you have a lot of stuff rotating in random directions, then they tend to bump into each other a lot. The result is that stuff is either ejected or gets a change to its direction. Now, if you were to sum up all the stuff, *some* direction is going to have more stuff moving along it than the rest. The other directions will tend to cancel each other out, leaving you with the direction with the *most* stuff to be the remaining one.", "Actually, there are several types of galaxies- Elliptical (Round), Spiral (The flat one in question), and undefined (no specified shape). The reason why spiral ones are flat are because systems of stars are an orbit, and therefore are going on usually the same path, which cannot happen in a spiral galaxy.", "I've heard the term \"conservation of angular momentum.\" Can someone explain that? Or is that wrong?", "Try spinning a mop around its axis, and see what the treads do. If a group of (celestial) bodies move in a way that implies a center of gravity between them, centripetal force will flatten the spinning collective. Minutephysics has a great vid on it. Don't have the link now. Anyone?", "Additional question: Our solar system is usually represented in the popular media as flat, i.e. all planets (excluding Pluto) orbiting in the same plane. The exception is Pluto, which orbits in an angle (and having more of an elliptical than a near-circular orbit). Is that truthful? And if so, is that because of the same reason (i.e. like a pizza)?", "Rotating things spread out. But also, there are lots of round and roundish galaxies. Ie: these are close neighbors to the Milky Way [Magellanic Clouds]( URL_0 )", "Same reason pizza dough flattens out when they smash and spin it in the air! Centrifugal force from the spinning brings an outward force while spinning. It's a similar reason as to why a bicycle gets more stable the faster the wheels turn!", "Things start spherical, rotating in all directions. Over astronomical timescales, things collide with eachother until they start to look flat. At this point, collisions are quite rare, so things continue to rotate in a relatively stable, flat shape.", "short answer because you cant spin in every direction at once. long answer, You can only spin in a single direction at a time, even if you add other rotation vectors to the spin all that does is transform the original rotation vector (it changes the direction of the spin), this is why galaxies are planar disks instead of a spheroid blob", "Any dust cloud in space has some kind of overall angular momentum about its centre of mass. This means that it has one \"amount of going-around-ness\" that it prefers. This is a conserved quantity, so no matter what happens inside the cloud the end result will have the same amount of going-round-ness Imagine that the final galaxy lies on a sheet of paper. Any vertical motion, through the page, starts off essentially random, but because of this lack of preference friction will eventually even it out. Think if two dust particles approach from above and below the page, their collision will nullify a lot of each particle's vertical motion but their motion around the surface of the page will be unaffected. Particles that are already moving in the on the surface of the page experience less bumps from other particles, so eventually it ends up where all the dust particles are going in a circle in the same direction around the surface of the page. Take away the page metaphor and you have a galaxy. This is also why our solar system is really flat, the same friction effects caused our primordial dust cloud to collapse into a ring around the sun from which our planets formed, that's why the planets all line up and orbit in the same direction."], "text_urls": [["https://redd.it/2rpq0u"], [], ["https://youtu.be/tmNXKqeUtJM"], [], [], [], [], [], [], [], ["http://astropixels.com/galaxies/images/SMC-02w.jpg"], [], [], [], []], "score": [6935, 420, 284, 92, 61, 49, 21, 10, 10, 9, 8, 4, 3, 3, 3]}}, {"q_id": "61ceyf", "category": "Repost", "title": "Gentrification", "title_urls": {"url": []}, "selftext": "I recently stumbled onto this topic and have been largely confused by the controversy. I could easily see myself as a \"Yuppie\" moving into a poorer area to save money or to renovate a home. Why would this be a bad thing?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfdf6i6", "dfdkdie", "dfdf2n3"], "text": ["It's taking a place that's isn't so nice and making it a more desirable place to live and hangout. They do this by commissioning artists to brighten the scenery, getting investors to start businesses such as restaurant or bars, adding parks for people to relax at, and driving out \"undesirables\" by either jacking up rent prices or hiring security to shoo away the homeless. It is looked down upon by some because it gives an area a commercialized and fake feeling. On top of that, it crowds the area with a bunch of \"yuppies\" whom some people find annoying. Also, I imagine people that lived there before gentrification would be angry about rising rent prices.", "The knock against gentrification is that it often displaces people who have lived there longer, with lower incomes. Rents go up, Property taxes go up, and those with lower incomes can no longer afford to live there. While home owners who want to sell can benefit from increase property values, often they don't want to leave their friends, family and neighbors nearby, it may be close to their job, and lower cost housing may be in higher crime areas, etc.", "Because it ends up pushing up property values, taxes, rates, etc. beyond what the current residents can afford. If someone rich moves into an area and does up the house, it increases the value of property in the area. It means more affluent people coming in and doing the same, further raising the prices and status of the area. Eventually it is no longer affordable for poorer people to live there so they end up displaced. And poor people need to be able to afford to live in houses."], "text_urls": [[], [], []], "score": [6, 5, 5]}}, {"q_id": "61do0h", "category": "Repost", "title": "How did all the water on earth today get here originally?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfdpycl"], "text": ["We're not entirely sure, but there are two major theories: **1.** It has always been here and was integral to the formation of the planet. **2.** It arrived after the planet was formed, delivered by comets, asteroids, or other debris that was still flying around the solar system in the early years. The important thing to remember is that water molecules are abundant throughout the solar system, so the earth is not special by its presence alone. What makes Earth special is its size and distance from the sun that allows water to remain stable in a liquid state."], "text_urls": [[]], "score": [4]}}, {"q_id": "61eqad", "category": "Repost", "title": "Why do we see a bunch of strange colors and shapes when we press up against our eyelids?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfdyo0s", "dfe3272", "dfe1ea4"], "text": ["It's not damaging at all. Your eyes are always trying to see, but when they're closed they don't have any visual stimulus - putting pressure on them by rubbing or pressing on them makes them think that there's something to see, so they're lighting up trying to process it. [Further reading]( URL_0 )", "Similar question: With my eyes open, if I lightly press in the bottom left corner or one eye (pushing on the open lid not the eyeball) I see a black spot in the top right corner of my vision. Happens with the entire eye - any light press on one side = black spot on the other. Does anybody know about this? I asked my housemate a while ago but he said it doesn't happen to him.", "Follow up. Why does this not happen when I close my eyes and press?... Just black, maybe a little white but that's when I'm not pressing."], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/1tj8fp/when_you_close_your_eyes_and_press_on_them_with/"], [], []], "score": [26, 5, 3]}}, {"q_id": "61etdz", "category": "Repost", "title": "Why cannot objects travel at or past the speed of light?", "title_urls": {"url": []}, "selftext": "Also, what would happen if the object attempts to?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfdzl4d"], "text": ["Everything we say about science comes from a model - a group of theories that together describe the universe. We make observations, develop a model, use that model to make predictions, experiment and observe to confirm or disprove those predictions, and further refine the model. The best model we have for the universe is called Special Relativity. It makes many predictions that have been fully confirmed. It works like this. Time is just another direction, like length, breadth and depth are. Space and Time are really the same thing, so we call it 'spacetime'. Every item -literally everything - always travels through 'spacetime' at the speed of light. Particles without mass cannot travel through time, so must travel through space at the speed of light. Light is just such a massless particle, which is why it travels at that speed. Every item with mass - like a star, planet, person, coffee cup, dust mote or electron, can travel through space, if made to do so by some force. But it still travels through spacetime at the speed of light. This is why we experience time 'passing'. because we are forced to move through it. But the more we move through space, the less we move through time. It is like we are travelling diagonally through spacetime at a fixed speed. Eventually, if we are moving 'sideways' through space at nearly the speed of light, we practically stop moving through time. This is all very unexpected, and nothing like you'd expect from moving at more terrestrial speeds, but when we make things move very fast, we see just this happening."], "text_urls": [[]], "score": [7]}}, {"q_id": "61f28r", "category": "Repost", "title": "How does code translate to circuits?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfe0eyg"], "text": ["If you take a stripped clean cpu architecture with no sophistication, it is loading an instruction from memory based on the instruction pointer value, and decoding that instruction to signals used to control the cpu circuitry. Then automatically advancing the instruction pointer to the next instruction. This is called the fetch\u2013decode\u2013execute cycle. One instruction could be decoded to what signal levels to send to hundreds of other places in the circuitry of the cpu. Signals control if registers should store the value on the bus, control if registers should put their value on a bus, what operation the ALU should use on input values. Control if the latest comparison flags should control the storing of values. And so on.. A loop is nothing else but the conditional write to the instruction pointer register. So a while loop in a high level language is some test instructions for the condition, and the condition outcome is stored in a condition register, then followed by the conditional write to the instruction register based on a bit in the conditions, if it should jump to the instruction after the while loop, or just continue into the while loop for another iteration until its end, where an unconditional jump goes up to the test instructions again. Types of variables is a high-level construct. In assembly language everything is bits in registers and loadable from memory. Assembly instructions use these values for specific purposes. It is perfectly possible to multiply a memory address with another value, but the result value is not useful. It is however useful to add a value to a pointer (to calculate the address of an element in an array). Many high-high languages zero-initialize variables instead of letting them have the value of whatever existed in the memory where it is allocated. However, a modern cpu has lots of sophistication to make it run faster, but they all maintain compatibility with the above model. A compiler writer or developer writing a tight loop in assembly can use understanding of the sophistication to get faster running code though."], "text_urls": [[]], "score": [4]}}, {"q_id": "61f6we", "category": "Repost", "title": "Sleep paralysis.", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfe29il", "dfe23zy", "dfe1gqc"], "text": ["I'm not a scientist or doctor but I've had this since I was about 12, hundreds of times. When you go to sleep your brain stops communicating with your body to move/react so you do not react out on your dreams and potentially hurt yourself or those around you. Some sort of peripheral nervous system disconnection?? What happens is your mind wakes up without telling your body to. This can be terrifying and also include hallucinations. It has also been referred to as the old hag; an idea that some witch or demon is sitting on you and sucking your life away. When this happens I still sometimes get scared but most of the time I recognize what is happening and calmly pull myself out of it. If this happens to you and you're scared, focus on moving something such as a finger and once you're able to it will immediately stop in most cases.", "When you sleep your body releases chemicals that paralyzes you to prevent you from acting out your dreams. That is completely normal. However under certain conditions it is possible to be awake, or wake up while this is happening without the paralysis ending immediately, which is not normal. Some things that are known to increase to the risk of it happening are lack of sleep, irregular sleeping patterns and sleeping on your back. If it happens to you and you want to get out of the paralysis faster, here are some things that have worked for me: Being aware what is going on and not panicking. Focusing on wiggling toes and/or fingers. Don't be scared of the old hag, it's just a hallucination. Focusing on breathing or trying to breathe fast.", "Body thinks its asleep But you see things In real life But you're still dreaming So your mind makes you see/hear/feels things"], "text_urls": [[], [], []], "score": [11, 4, 3]}}, {"q_id": "61gs3c", "category": "Repost", "title": "Why do paper cuts on fingers hurt so much, even though they're relatively small?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfecnc2"], "text": ["Paper isn't sharp, it's ragged along the edge and just sort of rips it's way in rather than cutting. That's what makes it hurt, if you used a hack saw to cut yourself with it would hurt a hell of a lot more than a razor blade."], "text_urls": [[]], "score": [3]}}, {"q_id": "61jxvx", "category": "Repost", "title": "Why do many people feel safer when they're in bed with the blankets pulled up, even though blankets provide no actual protection?", "title_urls": {"url": []}, "selftext": "Not a judgement. I totally do this, too. I just don't understand it.", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dffaz73", "dff4zcd", "dffce1i", "dffmmju"], "text": ["Blankets with a particular level of weight activate pressure sensors in our skin. They tell us that we are \"covered\" and help with calming our hormonal responses. It's the same premise as \"thunder jackets\" for dogs. It's a calming sensation.", "Because you're \"covered\". IT doesn't matter if it's a thin piece of cloth that wouldn't stop anything, it's better than \"nothing\" It's the animal instincts in our brain telling us that being \"hidden\" is superior to not being hidden, and helps us feel better, even if the coverage is useless at anything but warmth.", "It doesn't provide physical protection, but you are still hidden and out of sight. Of course anyone can see when someone is under a blanket, but it might not be so obvious for an animal for example. Its just an instinct to hide when in a dangerous situation.", "I'm not sure on the scientific research behind this, but this is the theory I have heard. The idea is that it triggers the same sensation in the body as if we are being hugged. In social animals, a sense of security/safeness is primarily attained (especially in the younger years) by physical proximity to others in the pack (hugging or touching). It triggers the attachment system, which is basically our \"cool down\" system. There are different groups of 'happy' or 'pleasant' emotions. There are the stimulating ones (excitement, accomplishment, pride), which feel good but also make us feel more energetic rather than relaxed. All those \"uppers\" are the ones that motivate us to go out and *do*. And then there are the soothing ones that promote a sense of security (warmth, connection, belonging, togetherness - which are all to do with our social needs and generally promote a 'relaxed' sense of being rather than an energetic sense of being). So we rely on this affiliation system to calm down and relax - these are essentially our inbuilt \"downers\". The reason we don't literally need other people around all the time as we grow (unlike as a young child) is because we internalise the sense that we have people behind us (as in others care about us) and use this felt sense of connection to soothe us. Therefore, simulating the sensation of being hugged triggers the 'calm down' emotions, as does hugging a pillow or a soft toy. Based on this theory there have been weighted blankets created for people with depression and anxiety as the extra pressure/sensation promotes better sleep and more of a sense of security. As I say, this is the theory I have heard but I am not a scientist and have no actual expertise, so if someone else knows this to be bullshit, please do let me know."], "text_urls": [[], [], [], []], "score": [135, 79, 10, 6]}}, {"q_id": "61lni5", "category": "Repost", "title": "Why do most products cost \"X.99\" units of currency, rather than simply round up? [Economics]", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfff16m"], "text": ["Psychological pricing (also price ending, charm pricing) is a pricing/marketing strategy based on the theory that certain prices have a psychological impact. ... Thus, prices such as $1.99 are associated with spending $1 rather than $2."], "text_urls": [[]], "score": [5]}}, {"q_id": "61pefr", "category": "Repost", "title": "The recent bill passed in America that allows personal browsing data to be sold.", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfga4cp"], "text": ["In 2016, the FCC set up new rules for ISPs which would have taken effect this year. Basically, these rules would require ISPs to actually ask you before they sell your information - called opting in. Currently, you have to find their contact form and actually tell them they're not allowed to share your information - opting out. The Senate bill just prevents those changes from taking effect. So as assholish as the Senate is being... technically, nothing changes. Here's a summary of what the new rules would be, [from ArsTechnica]( URL_0 ): > **Opt-in**: ISPs are required to obtain affirmative \u201copt-in\u201d consent from consumers to use and share sensitive information. The rules specify categories of information that are considered sensitive, which include precise geo-location, financial information, health information, children\u2019s information, Social Security numbers, Web browsing history, app usage history, and the content of communications. > **Opt-out**: ISPs would be allowed to use and share non-sensitive information unless a customer \u201copts-out.\u201d All other individually identifiable customer information\u2014for example, e-mail address or service tier information\u2014would be considered non-sensitive, and the use and sharing of that information would be subject to opt-out consent, consistent with consumer expectations. > **Exceptions to consent requirements**: Customer consent is inferred for certain purposes specified in the statute, including the provision of broadband service or billing and collection. For the use of this information, no additional customer consent is required beyond the creation of the customer-ISP relationship."], "text_urls": [["https://arstechnica.com/information-technology/2016/10/isps-will-soon-have-to-ask-you-before-sharing-private-data-with-advertisers/"]], "score": [5]}}, {"q_id": "61pf8i", "category": "Repost", "title": "What would the consequences be if a United States President was Found to have Colluded with a Foreign Power for Election?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfg9bdd"], "text": ["Nothing. His party controls Congress and his voters don't care about that. Most likely, it will just be used to distract us from his dismantling of our safety nets and large give always to the rich."], "text_urls": [[]], "score": [3]}}, {"q_id": "61phy6", "category": "Repost", "title": "Why are most homeless people guys ?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfgb3rt", "dfgb0fn"], "text": ["One contributing factor may be that women, especially women with children, tend to get some priority when it comes to shelters and housing programs.", "Just as said previously, men are more prone to mental disorders. This has to do with genetics with the X and Y chromosomes. Ex. Color Blindness. The Y chromosome can't help deny the trait, so the X chromosome can freely cause the disorder. Meanwhile in women, the other X chromosome can help keep the gene recessive. Therefore in the end, disorders can be shown in men, more than women. It's just way more common to be recessive in females. Now that that's out of the way, Studies have shown that a majority of homeless people are usually struggling with some type of mental disorder. Usually, these homeless people are problematic in the fact that, some of them choose to be in their current state. Some of the mental disorders impacting the population is good ol' schizophrenia. This is probably not the best answer, but I think it's stable enough to go with."], "text_urls": [[], []], "score": [21, 9]}}, {"q_id": "61piwj", "category": "Repost", "title": "Why is over the internet calls (VoIP, FB Messenger, etc.) audio quality still overall worse than that of cellphone calls?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfgasob", "dfgaxsf"], "text": ["Have to disagree man. Most VOIP calls I make are better than ANY cell call. Maybe you have a better network? And Skype calls... those are now being used for livecasts on tv and radio because they're SO much better than cell or landline.", "It depends on your internet connection. When you are calling with any of the examples you stated the sound quality depends on your internet speed and the internet speed of the person you're calling. If you 'just' call someone the quality depends on your connection to the provider. So if internet speed > connection with provider your internet calls will sound better than regular ones. (I am by no means an expert on this subject so i could very well be wrong, just seems like the logical explanation to me)"], "text_urls": [[], []], "score": [5, 3]}}, {"q_id": "61puva", "category": "Repost", "title": "What do VPNs do, and why is it worth using one?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfgdr6d"], "text": ["VPN stands for Virtual Private Network. The most basic description is that another computer is acting as a *relay* for yours. This other computer can either be run by a VPN provider, or by a company you work for. When using VPN, all of the information coming and going out of your computer *doesn't* go straight to it's destination. Instead, it's encrypted and sent to the relay machine first, who *then* sends it on it's merry way to it's final destination. There's a few perks to this. * It means all traffic passing through your ISP is encrypted and they cannot read it. * This also applies to anyone who might be snooping the coffee shop wi-fi or any other stage along the journey, if they managed to get your data in transit they wouldn't get anything. * If the relay server is setup attached to a corporation's private network, then VPN users can acess the server and talk to other computers inside the building as if they too were on-site, even though they're not. This means they only need to poke one hole in their network. It's not perfect. If the VPN provider is compromised in some way you could get snooped, and if your own computer is compromised youcould get snooped. But it's a lot better than nothing, and in the corporate world is considered a normal seurity measure."], "text_urls": [[]], "score": [3]}}, {"q_id": "61qc5u", "category": "Repost", "title": "How is it that lobbyists offering things to lawmakers doesn\u2019t qualify as an illegal conflict of interest?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfgi1lu", "dfghndy", "dfgi2xm"], "text": ["Well, Timmy, it's ok because the lawmakers said it's totally ok and passed laws that say it's totally ok.", "\"Buying votes\" is exactly what it is. Politicians are directly influenced by lobbyists which is why lobbying is despised. Corporations can bribe politicians through lobbying.", "What? Buying votes? No... that's ridiculous. The lobbyists are just showing their support for senators, obviously the senators never let any donations affect how they vote."], "text_urls": [[], [], []], "score": [6, 5, 3]}}, {"q_id": "61s7mc", "category": "Repost", "title": "Why cant we fold any paper more than 8 times ?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfgtzih"], "text": ["Little bit if physical and a little bit of math. Every fold doubles the number of layers that need to be folded while halving the size of the area to fold. 8 times is the same as 2^8 or 256 layers. If you start with a 1ft by 1ft sheet of paper, you would have 256 layers of paper with 0.046 square inches of folding space, or a 3 dimensional rectangular cuboid that is 0.046\u00d70.046x0.99 inches. Interesting fact: if it were possible to fold a piece of paper 103 times, its thickness would be greater than the diameter of the known universe. Interesting facr 2: the record for folding paper in half the most is 12 times. This was done with 4000 feet of toilet (3/4ths of a mile)"], "text_urls": [[]], "score": [11]}}, {"q_id": "61ustk", "category": "Repost", "title": "Before eyeglasses were a common product, how were people with poor vision able to cope with it?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfhgg6e", "dfhgctx"], "text": ["You don't need great vision to farm. Back when most people didn't get \"book learning\" it wasn't necessary to read so fairly poor eyesight wasn't a terrible hindrance.", "Most people with glasses can still walk around without. Most people historically were farmers and didn't need to read. A magnifying glass could be used if you were a scholar and needed to read."], "text_urls": [[], []], "score": [3, 3]}}, {"q_id": "61xuiw", "category": "Repost", "title": "Why can't price tags in the US include sales tax?", "title_urls": {"url": []}, "selftext": "When I worked in retail back in the early/mid '90s, we would get constantly updated price tags based on regional sales and products. The POS terminals were connected to the same AS400 mainframe and the local tax rates were updated automatically. I've read many comments saying that it is too difficult to keep up with state and municipal sales tax changes, but it didn't seem to be an issue with the POS registers. That was 20+ years ago. Is there still a significant technological barrier or just corporate inertia?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfi73n5", "dfi5rcg", "dfi7mcw"], "text": ["1) Some groups and people are exempt from some sales taxes. It is easier on the cashier if they do not have that tax already baked into the price. But this is less of a problem with computers. 2)This is a bigger one. Every city, county, and State has the right to put a sales tax on things. This means that it will be difficult to advertise things because you would have to have a different ad for virtually every single store location. That is extremely expensive for a company. 3) The biggest reason is that people are more likely to buy goods with the lower price on the shelf. By having taxes not included you make things look cheaper and psychologically people are more inclined to buy them. It is the same reasons things are price with 99 cents rather than rounding to the nearest dollar.", "It has never been a technological barrier. However retailers want to announce the lowest price possible when customers are deciding on weather or not to buy something. If the price tag say $1.99 you might be more inclined to take it to the checkout then if it said $2.19. But this is not a good reason to prevent legislation for this so they present the argument that it is too difficult to keep up with the local regulation.", "Most retail locations do not have digital price tags for their products and must print them every time there is a change in price. Paper is expensive and constantly reprinting signage for items that do not regularly change their price would be wasteful. Also, some signage is mass printed for all stores (think \"SPECIAL SALE!\" signage and such) that would be very expensive to print separately for each store's individual taxes."], "text_urls": [[], [], []], "score": [7, 4, 3]}}, {"q_id": "61ycyj", "category": "Repost", "title": "What is the fifth dimension like?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfi9nf6", "dfi9mh7", "dfibst4", "dfimigi"], "text": ["Time is not exactly seen as a fourth spatial dimension. It's often used as a representation, but a classic example of a four-dimensional object would be the Tesseract, or Hypercube. It is basically not really imaginable for us how higher dimensions work, just like a two-dimensional object could not fathom a three-dimensional one. It would appear like a shape changing size when passing through the flat surface.", "Don't know about the others, but the [5th dimension]( URL_0 ) is kinda R & B, pop/soul.", "If we forget about theoretical physics for a moment and focus on the world as we've seen it up until Einstein(Newtonian physics, if that tells you anything), then the world is 3-dimensional. There is no 4th dimension, 5th dimension, or any such things. Just our 3 dimensions to move about. Now, it's also important to understand that we talk about world being 3-dimensional. Dimensions however aren't places. You can't travel there. There is no way you can travel to \"second dimension\" or \"third dimension\". 3-dimensionality just tells you that in our world, there are 3 directions you can go toward. How you decide which direction is which is up to you, the only thing that doesn't depend on your choice is the number 3. So \"fifth dimension\" looks exactly like \"third dimension\" looks like: Absolutely nothing sensible. What could look like something is \"5-dimensional world\", where you had 5 directions to go towards. Now, humans are bad at imagining directions that go beyond \"up/down, forward/backward, left/right\". Mathematically there is no problem at saying there is 4th dimension, but we have trouble visualizing it. Modern physics kinda claims that there are more dimensions, but that they're like, really small. It's not different from how string is sort of 1-dimensional if you look it from far enough, you can only go forwards and backwards on a string. But if you look reeeeeally close, you'll notice extra directions, you could go around that string, left, right, forward and backward, but that movement gets lost if you look from far away because there's so little room to move in those directions. Modern physics basically says that the world is like this, there are tiny dimensions that only allow very little movement about them, and we're too huge to notice that detail. Theory of relativity on the other hand claims time is 4th dimension, and it creates this concept of \"spacetime\". Time kinda starts looking like direction you can go towards in Einstein's theory, but it never quite becomes the same as other directions. I don't really understand it well enough to explain it. The point is: * Dimension is not a place * No one can quite imagine higher dimension visually * Dimensions higher than 3 aren't part of everyday experience * Modern physics uses higher dimensions in at least two different, contradicting ways", "When you're writing down a bunch of properties of something, the number of properties is called the dimension. We usually think of a pack of cards as being 2-dimensional: (number, suit). We use two numbers (latitude, longitude) to specify a point on the surface of the earth, so the surface of the earth is 2-dimensional. The pixels on a computer screen have different amounts of red, green, and blue light, so the space of colors the screen can represent is 3-dimensional (R,G,B). An animated gif is six dimensional: you have to specify what the color is (RGB) at each position (x,y) and time (t). Sometimes physicists talk about how spacetime might have ten or 26 dimensions. In those models, the extra dimensions we don't see are \"curled up\": an animated gif has a time dimension that curls back on itself, since if the gif lasts for 5 seconds, then it's showing the same thing at t=6sec as at t=1sec. If you look at a garden hose from a long way off, it looks like a one-dimensional thing (how far along the hose?) but when you get up close, you can see the other dimension (what angle around the hose?). The curled-up dimensions are supposed to be around one Planck length long (the size of a proton to the size of a meter is the same as a Planck length to a proton)."], "text_urls": [[], ["https://en.wikipedia.org/wiki/The_5th_Dimension"], [], []], "score": [14, 5, 5, 3]}}, {"q_id": "61yg3k", "category": "Repost", "title": "How was the second invented", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dficm05"], "text": ["A second is the *second* split of an hour, divided into sixtieths. First you have an hour, which you divide into sixty parts, the minutes, and dividing each of those parts into sixty new parts results in a second. The reason why its divided by 60 and not some other number like 10 is because the system has its roots in ancient civilization like the Babylonians, who used 60 as a base instead of 10 like we do. 60 might seem like a random number, but it isn't. It has very many divisors - 1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30 and 60 itself. It makes for a pretty natural and sensible number base to play around with when it comes to math and commerce."], "text_urls": [[]], "score": [4]}}, {"q_id": "61ygum", "category": "Repost", "title": "How do pronunciation characters work in dictionaries?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfi9fd8"], "text": ["The Oxford version uses the [International Phonetic Alphabet]( URL_0 ) which, while more complicated, is also more precise. For example, in the more 'layman friendly' URL_1 version, how is _per_ pronounced? Does it rhyme with _fur_, or _air_? The IPA symbol \u0259 tells us precisely that it's a schwa, the kind of relaxed sound we'd use for comm_a_ or _a_-fraid."], "text_urls": [["https://en.wikipedia.org/wiki/International_Phonetic_Alphabet", "dictionary.com"]], "score": [6]}}, {"q_id": "61ys7s", "category": "Repost", "title": "The year 2038 problem for computing systems?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dficaxb", "dfibso2", "dfic3mn"], "text": ["**Background information** Whenever you stored data in the computer system, you allocate a certain amount of space in memory for that. And you can't go over that space. There are physical limitations to memory. You have to buy it. And fifty years ago, it was **much** more expensive than it is now. (I paid $130 for a 128 **megabyte** hard drive around 1989. Imagine what you would have to spend to store all the names and demographics on a group of people for a university or government office.) Imagine that you're writing a database for a group of your friends that include Mary, John, Frank, and Lisa. Looking at your data you see that first names tend to be four or five characters long. Maybe you allocate a few extra characters in case you get some weirdo with a long name. So you set your first names field to be six characters. And then along comes Abraham and Roseanne. How do you store their data? **Historical Reference** Back in the 1970s, the Air Force set up a computing system for payroll. Back then memory was very expensive, so as much as possible was done to limit how much information was stored on the computer. Think about a personal check. A lot of information is already printed on the check. The stuff that stays the same: your banking information, your printed name, your address: that's all pre-printed on the check. The stuff that changes from check to check\u2014the payee and amount\u2014is the only thing that gets filled in. Businesses would have a form with as much information as possible already filled in. The computer would store and then generate only the information that changed. The Air Force actually printed \"197\" on their forms and only stored the final digit of the year. As 1980 approached, they realized they had a problem. They fixed the problem by adding another digit, DOUBLING the space they required for year data, but they made a very bad assumption. > Some programmer: \"You know, this problem is going to reoccur in 20 years.\" > Somebody with higher rank: \"There's no way we will still be using this software in 20 years.\" The problem was, it's actually much easier to add code modules to a large program to make it do new things than it is to rewrite an entire program from scratch. So as 1999 approached, people realized that their old two-digit date systems were still everywhere, and on January 1, 2000, it would look no different from January 1, 1900. **2038 Specifically** UNIX systems calculate dates based on the number of seconds since January 1, 1970. They store this information in binary in a 32-bit signed integer. The first digit is 0 if positive, 1 if negative. The rest of the 31 digits are a binary number 1,111,111,111,111,111,111,111,111,111,111 in binary is 2,147,483,647. That many seconds after midnight January 1, 1970 is exactly 3:14:07 UTC on Tuesday, 19 January 2038. At the next second, the counter goes to 10,000,000,000,000,000,000,000,000,000,000 and to computers all over the place (the Internet runs on UNIX) it will look like we are back in 1901. Systems are already being affected by this. The Congressional Budget Office can't run forecasts past 2037. How do you calculate interest payments on a 30-year loan after 2008? (Answer: on a Windows box.) So? We've got 21 years to solve this problem, right? **That's exactly how much time we had between the discovery of the Air Force payroll problem in 1979 and Y2K.**", "Time on a computer commonly uses the starting date of the 1st of January 1970 at 00:00:00 UTC and is counted up in seconds. The time will be stored in memory as a 32-bit integer which means it can have 2^31 unique values or 2,147,483,647. If you try to add in anymore it causes issues sometimes the computer may crash or sometimes it may reset or other times weird things can happen. 2^31 seconds since 1/1/1970 00:00 is 19/1/2038 somewhere around 1pm UTC (Using the UK date format btw). How much can this effect? Pretty much everything electronic. The internet runs on databases that use SQL to get information, anything relating to time may break. Autopilot systems on plans need the time so they're at risk. GPS uses time to get your location so everything that uses a GPS has a potential to break. The solution is to move to 64 bit systems as soon as possible. Which we're already doing for other reasons so it's not something to panic about. This would give us 2^63 seconds of time. That might not sound a lot and you might be worried about this running out but that's not for another 290 billion years or so.", "That's the time UNIX time rolls over signed 32bit integer storage capability. 32 bits just tells you how many binary digits you're using to write down a binary number. 32 digits. It's not unlike to having 2 decimal places to write down a number. After 01 comes 02. After 11 comes 12. But after 99 comes..? With computers, result is either an error, or 00. Year 2038 is when signed 32bit binary number used to indicate time and date rolls over its limits. Unix time itself is just the number of seconds that have passed since New Year's eve 00:00 of 1970. It's what most computer system use to indicate time and date."], "text_urls": [[], [], []], "score": [19, 10, 3]}}, {"q_id": "61zkyk", "category": "Repost", "title": "Why is 36.7 degrees celcius the perfect temperature for a shower, but 30 degree weather is too hot? (if you're Irish like me that is)", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfiid53"], "text": ["You shower for maybe twenty minutes at a time, which is enough to warm your outer body temperature and it feels warm and comfortable but not enough time to hugely affect your internal temperature. If you spend too long in the hot water, you might notice how you'll start feeling tired and weak. That's because your body is overheating, and you might even feel a little dizzy if you overdid it too much. That's one of the very first signs of heatstroke, and if you stayed in hot temperatures too long you'd start seeing more serious signs too. But if you're outside, you're spending longer periods in hot weather and breathing in hot air, which itself raises your internal temperature faster. Your body will start sweating to cool itself down, which can leave you feeling dehydrated. This makes it harder for your body to cope with the stress of heat, and your body will start making you feel uncomfortable as one of the first warning signs to tell you to get to somewhere cooler."], "text_urls": [[]], "score": [3]}}, {"q_id": "620vsf", "category": "Repost", "title": "Why do airlines price tickets at a remarkable increase close to takeoff (next day flights) when they know they're likely not to sell?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfitbaq", "dfitcy2"], "text": ["Those tickets actually do sell, because of reasonable market values. Air travel isn't about getting you to your cousin's wedding at the last minute. It is about business travelers. If there is million dollar business deal on the line, paying $1800 for a same day flight isn't that big a deal. In fact, those travelers expect those seats to be available, and are *happy* to pay that much, rather than not being able to travel. They consider it a valuable *feature* of air travel.", "Many people who book last minute have urgent matters/business and are willing to pay whatever to get there. Often it's business travel, where the person booking isn't the one paying in the end. So the airline might be better off selling 1-2 expensive seats than filling all 8 remaining at rock bottom -- same revenue and less luggage, fewer people to board, less weight/fuel needed"], "text_urls": [[], []], "score": [13, 7]}}, {"q_id": "622nd0", "category": "Repost", "title": "What exactly is freemasonry? What do freemasons do?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfj7zf5"], "text": ["It's just a fraternal club like the Elks or the Moose Lodge. They don't do anything creepy. They just keep their ceremonies secret. Sort of. There are a few documentaries that expose some of the ceremonies. If there was a conspiracy here then someone would have come forward just like all the people who left Scientology."], "text_urls": [[]], "score": [3]}}, {"q_id": "623s29", "category": "Repost", "title": "Why can't we just dump all our trash in molten lava to rid of it instead of having it seep and pollute the ground water while in the landfill?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfji0xj"], "text": ["The gasses released by burning the trash would be a huge pollutant. When the lava cooled, you'd still have rocks full of whatever didn't burn away."], "text_urls": [[]], "score": [6]}}, {"q_id": "624liz", "category": "Repost", "title": "If the primary colors are red/blue/yellow, why is the RGB model so popular?", "title_urls": {"url": []}, "selftext": "I'm just wondering what the difference is. If RBY are the primary colors, shouldn't they be the generic model that we use to distinguish colors?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfjpgti", "dfjqctq"], "text": ["> If the primary colors are red/blue/yellow They're not. There are two methods of creating different colors from starting, \"base\" colors. There's additive color (combining different colors of light, where each new color adds more to the overall color, getting it closer to white), and subtractive color (combining different colors of pigment, where each new color removes some color, getting it closer to black). The primary additive colors are red, blue, and green. The primary subtractive colors are cyan, yellow, and magenta. The red, blue, yellow color model is outdated, and mainly used in art. But you can't actually produce every color from red, blue, and yellow pigment. For instance, those colors can never produce cyan or magenta.", "They are a set of primary colors. There are many different sets, each of which can be combined to produce a different set of colors (called a gamut). RBY is easy to each kids, but isn't as dynamic as other sets. RGB is primarily used for additive color sources such as light. Added more colors adds wavelengths to the final color. You mix them all, you get white. RGB is used because it corresponds with how our eyes interpret color. CYMK (cyan, yellow, magenta, black) is commonly used for subtractive sources such as ink. They remove colors by absorbing wavelengths of light while reflecting others, so you mix them all you get darker colors. CYM are basically the opposite of RGB on the color wheel."], "text_urls": [[], []], "score": [10, 3]}}, {"q_id": "62535k", "category": "Repost", "title": "Where did all these different American accents come from and when did they start to form?", "title_urls": {"url": []}, "selftext": "For example, where the hell did a southern accent come from? What about a New York accent, a New Jersey accent? Since the colonists had British accents, why has the British accent not been retained all these years? Did it have anything to do with having Native Americans near, or are some American accents derived from Native American tongue? Is there a recorded time when these different accents began to appear, or when the erasure of the British accent in America occurred?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfjt50l", "dfk1f68"], "text": ["The way people speak in Britain has changed *a lot* since Britain started colonising America. So those original colonists didn't have \"British accents\" as they are now. [Here's a video about how Shakespeare would have sounded back then]( URL_0 ;). So Americans didn't lose their British accents as such. Their accents just diverged from the accents in Britain. Some argue that a typical American accent is actually more similar to those old British accents than a typical modern British accent. Particularly in the way R is pronounced.", "Many original colonists were British, but don't forget that America is the melting pot! For example, my great great several greats over grandfather came from Scotland in the 1600s and was part of the first ever group of pioneers to explore and settle in Tennessee (which to me is kinda cool!), those first settlers there were for the most part all Scottish. Different parts of the country were explored and pioneered by many types of cultural groups, bringing along not only their own languages and slang, but their own customs. This is most easily seen today in the Creole habits in Louisiana from French colonization (before the Louisiana purchase, it was owned by Napoleon) and the Mexican influences in the southwest such as Texas."], "text_urls": [["https://www.youtube.com/watch?v=gPlpphT7n9s&amp"], []], "score": [25, 4]}}, {"q_id": "625x93", "category": "Repost", "title": "Classes and Objects in programming", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfjy7sg", "dfjyeqm", "dfjy8wg"], "text": ["A class is essentially a description of *how* a thing should work. An object of a class is an actual working thing, that fits the description. Example: A car has four wheels, an engine and a chassis. Using the pedals, you can accelerate or stop the car. Using the steering wheel, you can turn the car. This is the *class Car*. The Audi A4 my dad has in his garage, fits the description of the class Car. It has four wheels, an engine, and he can use it to actually drive around. This is *an object of the class Car*.", "Class = blueprint/plan Object = thing made from that blue print In programming creating an object from a class is known as construction. In C#/Java it would be something like this: var fordMondeo = new Car(); forMondeo is an object created from class Car.", "you can define attributes(variables) and methods(functions) that belong together or are to be used together in a context. the definition itself is the class. if you create values based on that class you are creating an object. an object is to a class what a variable is to a datatype. example: classname: human Attributes: gender, age, haircolor methods: born, move, age the above is a very basic definition of the class human. an object to this class is an individual person that has its own gender, age and haircolor. the person is able to be created in the first place(born), able to move and able to age(change its' attribute age) it is also possible to create multiple different objects/persons that have different values to their attributes"], "text_urls": [[], [], []], "score": [18, 7, 4]}}, {"q_id": "6269fv", "category": "Repost", "title": "VPNs", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfk2xs0", "dfk45rf", "dfk4ma9", "dfk2yva", "dfkf3cm", "dfl53eq"], "text": ["Virtual Private Network A system whereby you can connect to another computer over the internet via a secured 'tunnel'. This is different to connecting to a website or other computer via a simple SSL link as it creates a virtual network adapter on your PC and IP addresses are privately assigned to those adapters, thus making it a private network. When you connect this way, you could use a PC in Korea to connect to the internet, which in effect makes your PC in the UK or US look as though it is in Korea, since the Korean host is acting as a gateway to the internet for you. So your PC could be seen as creating a tunnel from the UK to Korea and emerging on the other side and accessing the internet or other resources there. Uses: - Being part of a big private corporate network - Pretending you are in another country when you want to access geo restricted resources - Totally secure file transfer between peers", "So, when you send data it goes to your ISP, who read the instructions that come with the data and pass your data on to whoever you want to send it to. A VPN is a middle man. When using a VPN you lock your data in an encrypted bag with instructions on the outside saying 'send everything to my VPN server'. Your VPN server is the only one with the encryption key to read your data. Your VPN server will now unlock your encryption bag, take the data out, and send it to a different ISP along with the original instructions of where it should go. Good VPNs won't read your data when they do this. The key thing is that none of these bags are marked, and lots of other people are using your VPN server. That way as soon as your encryption bag enters the VPN server it gets mixed up with all the others and nobody knows where it came from, so nobody can trace the data back to you. Unless of course you leave some identifiable information inside the bag with the data, something that plugins like Java tend to do a lot. One thing to remember is that expert intelligence services will find ways to trace everything back to you if they have an interest in doing so. VPNs are not protection for doing wildly illegal stuff. But they will work against automated systems that log data traffic, public routers that are tracking what you are doing, and ISPs that want to sell your data off to advertisers.", "Open internet: you and neighbor pal, Jimmie, each yell out from your respective bedroom windows to talk to each other. VPN: you and Jimmie run a single, physical, powered telephone system between your bedrooms. Obviously it's much more complicated but that's the ELI5 version.", "First and foremost: Explaining VPNs in general is quite a difficult task, if my answer does not satisfy you, please clarify what you want explained about VPNs. General explanation: VPN means Virtual Private Network. What this means is that a VPN connection (whichever kind is used) will connect 2 seperate networks over a public medium (usually, the internet) so that it seems as if the networks were directly connected via a direct wire connection. There's a number of uses for technology like this, for example to link home office workers to the main office or to connect 2 different offices (Company HQ in City X with Remote Office in City Y). VPNs are necessary because these networks usually transmit sensitive information (client data, company secrets, ...) which should not be send via the public internet. There are different technologies to implement VPNs (IpSec and SSL) but explaining these and the differences between them would probably go beyond the scope of ELI5 and this question.", "There are, however, some alternatives to VPNs, which can require fees to set up. There are the freely available Tor \"onion\" protocol and the Invisible Internet Protocol, or i2p, also known as the \"garlic\" protocol. i2p is easier to understand. All hosts connected to the garlic router network act as anonymous nodes. Your connection is doubly encrypted and your initial access point could be any garlic router in the network, and makes it appear that all of your packets originate from that IP address. Packets take random paths through the network to obscure their origin and destination. It is incredibly secure. Tor operates in a similar, but more complicated, manner. P2P sharing of network resources for the purpose of obscuring identifying information. I2p is more versatile as it supports all types of protocols including anonymous torrenting. Tor is strictly a hypertext system. Both protocols can be used to access the \"Dark Web\", which is not accessible by normal http/https methods. This region of the web contains everything from benign freedom of information and political interest sites, to more nefarious things like drug trafficking, arms dealing, even hitmen...contrary to popular belief though, most people simply want to browse anonymously an avoid the illegal sectors of the darknet.", "Imagine two semi trucks driving down a highway One of them is an open, flat bed trailer hauling a farm tractor. The other truck is a walmart box trailer. Your internet connection with a vpn would be like the walmart box truck. You can see it moving (your internet traffic) but you don't know what's inside. iPhones? Clothes? Food? Who knows, only you do. Your internet connection with no vpn would be like the flat bed; anyone that looks at it can easily see what you're trafficking from where it started, to where it ends. But there's a little more. With a vpn it would be like If you wanted to move the truck from NY to FL...but the truck stops in Toronto first, switches contents to a completely different trailer, then heads off to fl. While you can still track where it came from, it will be much more difficult than a one way trip."], "text_urls": [[], [], [], [], [], []], "score": [17, 13, 7, 4, 4, 3]}}, {"q_id": "629ed6", "category": "Repost", "title": "Why cant we go faster than the speed of light?", "title_urls": {"url": []}, "selftext": "Ignoring the \"you need unlimited energy\", what makes it that there comes a point where we just can't accelerate anymore?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfkum55"], "text": ["Even with unlimited/infinite energy it won't happen (though you can get quite close). When approaching the speed of light, more energy is converted into mass than is converted into increased speed, right up to the point at 0.999999(etc)c, all the additional energy would go into increasing mass instead of speed. There are two fundamental rules at play: Firstly that the speed of light is the upper limit of speed in the universe (otherwise causality would break down - you could see an event happen before it actually happened, for instance), and secondly that energy can't be created or destroyed. If you keep pumping energy into an object which is already travelling at 0.99999(etc)c, the object's energy increases, but its speed cannot. Kinetic energy is calculated as 1/2mv^2, and once v^2 is fixed (at ~c^2 ), the object's kinetic energy increase is converted to mass. Source: Am constantly travelling at circa 299,792,457m/s. Mass more than a large moon."], "text_urls": [[]], "score": [3]}}, {"q_id": "62a9rt", "category": "Repost", "title": "Why is lobbyism normal in the US? What's the difference to corruption?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfl9i6u", "dfl08lv", "dflbix8", "dflf4gu", "dfl22ki", "dflho0b", "dfl97y0", "dfli4uc", "dfl27wn", "dflpb6v", "dfl94nu", "dflls75", "dflixjx", "dfl7q5s", "dfla25o", "dflame2", "dflgbog", "dflc92v", "dfl9d5c", "dfljd9q", "dfla1d0", "dflea5q", "dflfwzh", "dfldvqa", "dflgiwc", "dfl9y2n", "dflf3zr"], "text": ["Lobbying in its current state evolved from a more acceptable practice of simply getting advice from people knowledgable in a given field. For example: If you are trying to enact reform on law enforcement, a congressman who has little interaction with the police would have a hard time drafting legislation to address any of the prevalent problems. Therefore lobbyists would come to the Congressman to give their perspective. Activists from groups such as the NAACP or ACLU might give their opinion on the problems with how law enforcement currently affects people negatively, so he would know what problems need to be fixed. Representatives from the police union might give their opinion on the reasons officers act with the protocols they use. The congressman needs this kind of information to do their job effectively. The reason lobbying in it's current form is often thought of as pseudo-corruption is that the theoretical lobbying described above requires access to politicians and open communication. This is also more or less a given due to constitutional freedom of speech. Furthermore, it is somewhat of a necessity to have an organized media campaign and infrastructure if you want to run for office on a large scale, such as when running for a congressional district that expands far beyond your own city. As a result, most politicians need to spend money to campaign, and the law thus allows people to donate to politicians. While this may seem like it invites corruption, consider the alternative: The law cannot restrict an individual from spending their OWN money on a television ad to promote themself, due to freedom of speech. So if there was no mechanism for politicians to raise money, almost all large scale political campaigns would be inaccessible to anyone who was not privately wealthy or famous. Allowing fundraising makes it theoretically possible for anyone to run an effective campaign so long as they have supporters. The result of these two things: The open access of politicians to lobbyists as a necessity of the job, and the legality of fundraising as a necessity of campaigning, means that anyone can make their wishes known to politicians and can donate money to them if that politician ends up doing what they wish. From a technical perspective, there is a simple way to avoid corruption in the legally culpable sense: If you do not make an explicit or legally binding promise of payment as a result of a specific action on the politician's part, it is not a bribe. You are simply exercising your legal right to talk to your local government representative, and your legal right to donate money to that candidate. The loophole comes from the fact that even if your candidate fulfils their promise, there is no guarantee that you will actually pay them, despite your informal promise. Or inversely, if you donate to a candidate there is no guarantee that they will take the actions you desire. Without such a direct provable cause/effect, you can't definitively prove corruption. EDIT: To address the common responses in the comments: 1. I am not trying to advocate or condemn the current system. The question asked why lobbying isn't legally corruption, so I explained what the current system is and the reasoning for how it resulted, and did so in a neutral tone, but I don't make any claim as to whether this is a good or bad system. 2. Many bring up Publicly Funded Elections, where the government gives all candidates money to run. This already exists, to a degree. For example, any political party which achieves a certain threshold in a presidential election gets federal funding in the next cycle. The reason that this alone can't solve the problem is that the Constitution can't stop an individual from campaigning on their own money, so even with public funding a wealthy person is very advantages over a poor person. 3. As for WHY we can't block individual spending on a campaign, this was the interpretation of the supreme Court on the case of \"Buckley v Valeo\". Due to the wording of our constitution, such a law would be invalid here, Despite it being legal in some other countries. Obviously the Constitution can potentially be amended, but that's a broader conversation than I am focusing on with this comment.", "Keep in mind that Lobbying is just talking to your representative, and you can be representing a group of people when you do it. You're informing a politician of your group's wants and needs. That's it. There doesn't need to be money involved. A few years ago, the US Supreme Court determined that restricting money = restricting speech (this is colloquially known as Citizens United if you want to see more info). Now, you still can't put money directly into these politicians' hands. But you can give it to a group that supports them (A Super PAC, which they can *almost* do whatever they want with the money. It's very flimsy, as far as regulations go). The practice of lobbying by itself isn't corrupt, but because money = speech in the eyes of the law, that allows for corruption to happen legally.", "> Why is lobbyism normal in the US? First, you need to ask, what is lobbying? The 1st Amendment to the Constitution of the US says: > Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof; or abridging the freedom of speech, or of the press; or the right of the people peaceably to assemble, and **to petition the Government for a redress of grievances.** So, we all have the right to go into our local politician's office and be heard. If I want to go to the office of my House Rep, he has to hear what I have to say. It's my right to *petition*. Same goes for my city councilmember, mayor, State Rep, Governor, Senator, and even the President. They all have to hear what US citizens have to say. Now, as an example, let's say you want to see a Congressman. There are 435 Congressional Districts in the US, each representing populations of 711,000 people. Imagine the queue you'd have to make if everyone in the district wanted to *redress grievances* with their Congressman! So, to make things more efficient, people created companies that, when hired, would petition your politicians for you. This is called lobbying. This is why lobbying is legal, and population (and geographical) sizes is why it's normal. It's very hard for an American in Hawaii to visit their Representative in Washington. And it's very hard for 711,000 people to be heard all at the same time. > What's the difference between lobbying and corruption? Lobbying is associated with corruption because special interest groups would donate money to politicians who are open to their ideas. For example, let's say Congressman A is in favor of the oil industry, the oil industry lobbyists would be more willing to donate money to Congressman A's re-election campaign. In contrast, the solar industry lobby would not only abstain from donating to Congressman A's campaign, but they'd be more willing to donate to Congressman B's campaign, because Congressman B is a proponent of solar power as an alternative to oil! This looks like corruption because it appears that money is being exchanged for votes. But, can we prove that's the case? Or is it the case that these Congressmen already agreed with a particular position, and lobbyists are simply endorsing these candidates because they agree? The law makes a very clear distinction: if money is given in exchange for votes, then it's corruption. So, if you say to a candidate \"Vote for this bill and I'll give $500K\", that's corruption; it's a bribe. However, if the lobbyists says, \"Remember that bill we talked about the other day? I saw you voted the way we like. It is clear that your worldview and ours are compatible, and since we like you so much, here's $500 for your campaign\", then that's not corruption. It is perfectly legal. It's a fine line, to be sure, but the law has drawn the line there, and in that fashion. Right to petition is an important right for any free society to have. In the United States, congressmen have been investigated and arrested for bribery. In other words, the US *does* prosecute outright bribery. So lobbyists and politicians need to be very careful to not cross the line. The good news is that the line exists. The bad news is that many people disagree about where the line is currently drawn, and believe it should be drawn elsewhere.", "What's so bizarre to me about most of the responses in this thread, is that 'in the US' has been consistently interpreted to contextualize intra-US politics. To be more specific, I was surprised that comparisons are not being made to other countries ie 'what does lobbying look like outside the US?' This is a fundamental question to ask, because many Americans don't realize that many countries around the world do not distinguish between lobbying and bribery. In fact, when US media outlets talk about bribery happening in other countries, the legalistic offenses often relate specifically to \"lobbying\" efforts. Read more cynically, the reason the US political system is thought not to have endemic corruption is because we have redefined what it means to be corrupt - not because we have uprooted corruption itself. **TLDR:** In many other countries, lobbying *is considered the same thing as* bribery. **EDIT:** A lot of replies appear to confound free speech and lobbying. There's a difference. I'm not trying to argue that actual free speech directed at politicians is necessarily lobbying. Ironically, this thread demonstrates why we have such issues in the first place around bribery. The courts in the US have exploited this to manipulate the definition of lobbying, political donations, etc (this is why we can't just say 'lobbying' in the US is the same thing as 'lobbying' in other countries). Funny how there was a Chomsky thread that hit the front page on the same day. *Actually, /u/BrotherPazzo explained this point much more concisely, so go check out his comment!* Also, most responses have referred to western democracies in their rebuttals - but see that's exactly my point. While there are western democracies that criminalize the equivalent of lobbying in the US, there are a great many countries (democratic ones!) outside the west that do the same. Apparently, we're not supposed to take their laws seriously.", "Lobbyism is normal in the US because of the constitutional rights to freedom of speech and \u201cpetitioning the Government for a redress of grievances\u201d. The eight largest lobbying groups in the US are US Chamber of Commerce National Association of Realtors American Medical Association General Electric American Hospital Association Pharmaceutical Research & Manufacturers of America Blue Cross/Blue Shield AARP Those cover a lot of people's interests, GE is 106,000 US employees alone", "Way too complicated answers. It's normal because multi national corporations and the establishment have bought off the process, rigged the system and made it normal. What is the difference from corruption? Nothing, except that they don't call it corruption. In reality, it absolutely is, and until that system changes the U.S.will not be a democracy as much as it is a oligarchy, catering to the desires of the elite/establishment. See? No huge multi paragraph answers required, it's quite simple, really.", "Lobbying doesnt even have to be immoral. If I start a petition that the government should do something about the heroin epidemic or other real problem, and pester congressmen about it, that's lobbying. Like most things humans do, its not the act itself, its the people involved who turn it slimy.", "Americans should quit trying to rationalise what is clearly just a corrupt system in the eyes of the rest of the civilized world, where such practices are severely prohibited. It's the law of the rich, plain and simple. Democracy of the highest bidder kind.", "As another comment mentioned, lobbying is just speaking to politicians about your needs and/or the way laws impact you. The problem is that people have very unequal access to politicians, and money greatly increases the chances you'll be able to have your voice heard (maybe literally). There are also concerns about direct bribes or more traditional forms of corruption in the process of lobbyists interacting with politicians. An example is simply eating a meal with a politician to talk-- who pays for that meal? I believe there are actually rules about that specific thing, but somebody will always believe they are too restrictive or not restrictive enough. And in general there are all sorts of opportunities for partnerships, payment, or gifts when your job is to hang out with politicians all day.", "As an Italian lawyer, i can tell you that in the vast majority of cases it would be considered corruption in here. The objection is \"but it's not guaranteed the politician will actually do x\" would just make it attempted corruption (still a crime). I'll give you an example. Say a local group has an interest in the local administration to green light a project, something like modernizing a harbor, because they'll profit from it (construction companies, unions). They make sizeable above the board perfectly legal donations to candidates, that need that money to run for office in that administration. That's lobbying in the US and textbook corruption in Italy. You can try to rationalize it all you want, but the simple truth is that politician in the US need money to run for office, this is provided by donations. Now why would that person/ group donate again if the promises made don't get fullfilled. So you have a politician that needs to fullfill, or at the very least do his best to fullfill, the promises made to the donor, and the only difference with corruption is that you have a legalized system in place and a different name for it.", "Paid speeches Campaign contributions Well paid non-executive board positions High paying corporate jobs after you've left office All of these are methods for washing bribe money. Many politicians who get these perks are taking them as payment for favourable legislation they have helped pass during their term in office.", "It's not corruption because it's legal, and it's legal because the super rich like owning politicians. If you or I approached a senator and offered him $100 bill to vote a certain way, we would be engaging in bribery. But if we funnel $100k into his campaign accounts through a web of various entities, in order to obscure our involvement, then we hire the senator's nephew to an executive position which he has no qualifications for, that's lobbying.", "I worked in a Maryland State legislature and was in charge of ethics in one of the representatives offices, which is indirectly tied with lobbying. Lobbying in itself is not an issue, tiny, community organizations do it all the time. Hell, paid lobbyists I've encountered were often quite frequently terrible, and ineffective, compared to local community organizations who often made quite convincing arguments about their issues. Problem is the Supreme Court ruling concluding that companies = people, and allowing these \"people\" to funnel unlimited amounts of money into politics. It is impossible to prove unspoken *quid pro quo* between business and politicians that happens because of this. As far as I can tell, that is mainly an issue on federal level, my experience with reps on state level was overwhelmingly positive, despite me being rather skeptical when I started there. At least in MD...", "Lobbying in the US is similar to bribery. I think you should already know how it works. The lobbyist represent a person/group/company will talk to someone in congress and will persuade him to vote a certain way so that the person/group/company they represent will help him in the next re-election (they donate the money to his Super Pac, and they dont have to reveal who donated that money to you, until way after the election is over, and by then, nobody cares... Stephen Colbert does a great coverage of this when John Stewart was running Stephen's Super PAC). Its a system that its hard to change, why? Because money wins elections. You can hire smarter people, or more people, air more ads, etc, etc... And its a system that everyone in the government know is wrong but there is nothing they can do about it because they all need the money to keep going. Also because presidential campaign takes almost a fking year, and its getting earlier and earlier to get your name out, while other countries presidential election are rather short. The longer the election campaign, the more money you need.", "I just heard this [this story]( URL_0 ) on NPR this morning about Professor Joseph Bankman. It's an interesting story of a man paying for his own lobbyist out of pocket to push \"no-brainer\" legislation, but going up against a corporation and California politics.", "Imagine you have a playground (the country) with a bunch of different sections for playing (various business industries) that has a person in charge that makes decisions about the playground (the government). You love slides and go to the park everyday to play on them. However there are some rumors going around that the person in charge is planning on implementing a rule of \"no one can be higher than 10 feet off the ground\". This is because kids were playing on swings and were getting up too high than getting hurt. However you know that the slide and other toys are actually higher than 10 feet and so they will be affected by this new rule too. So you, the jungle gym kid, and the monkey bars kid get together and have a friend of yours (the lobbyist) go talk to the rule makers. This friend knows all about safety and which parts of the park that are high off the ground and so you trust him to talk to the rule maker about changing this bill. Your friend does this and gets the rule maker to make the rule now say \"No swinging higher than 10 feet off the ground\". So that it doesn't affect the other equipment. The part where corruption gets involved is imagine that the sandbox kid hears about the original rule and likes it because it will mean more people will play in the sandbox. So he gets a friend of his to give the rule maker some money if they keep the text of the rule the same no matter what anyone else says. TL:DR - A lobbyist is an informed friend of an industry who's goal is to work with the government so that they are aware of the specifics of the group they represent. Corruption starts getting involved when they begin offering money and job offers to get what they or their industry want.", "In my opinion there is NO DIFFERENCE. Lobbying is the exact means by which the wealthy have taken over the US government, and I wish it could be severely limited. Unfortunately, the people with the power to impose limits on it are the very legislators whose political careers depend on it. Trump supporters on reddit have asked what he could do that would make haters change their minds about him. My answer: write an executive order severely restricting lobbyist access to members of Congress.", "I don't get why they don't just have a government run standardized election channel. It would literally just tell you who's running and shit about elections. Each candidate would get the same amount of air time for ads or whatever with a rotation for prime time or something and so on to make it unbiased. Maybe more of an organization then a channel. The National Campaign Organization. Have check and balances and shit, would ideally separate corporations from politicians by changing how Campaigning and election coverage operates.", "There will be many answers saying one is legal and the other isn't. They will also talk about how lobbying means you get your gov't rep's ear but not necessarily forcing that person into a specific decision. Those are in theory correct but that doesn't mean that it doesn't end up devolving into bribery. But in terms of why one is \"normal\" and viewed as acceptable and the other isn't, you can also look at it like this. Corruption is bribery for the benefit of a few. Lobbying is bribery for the benefit of a large interest group.", "Don't let the United States of Ammendment fanboys fool you, there is no discernable difference between corruption, bribery and lobbying in the current US political system. The only reason it's not addressed as such is due to this developing slowly over time than being blown out in a scandal early on. Of course everyone has/should have the right to speak to their representative but any exchange of money for time/ideas/orders is a dictionairy definition of corruption.", "Simply put, there is more than one type of lobbying. The main type we hear about is big corporate lobbying which is sometime accompanied with 'pay offs' to the politicians. However, there are also lobbyists for things such as Clean Water, Clean Energy, Social programs, ect. There are specific ways that the 'bad' lobbying occurs and rules that have to be followed. A good lobbyist will at least adhere to the rules. NPR just recently did a piece on this a few weekends ago with some previous lobbyists as guests. I tried to find it but failed sorry.", "There are going to be a lot more nuanced answers here, but the gist of it is that people with a lot of capital can just use that capital to legitimize nearly anything they want to do as long as it doesn't step on the toes of other people with capital. The modern lobbying context grew from the fact that everyone with capital benefited from having near-exclusive access to politicians, so it became the new normal by virtue of everyone with money participating. It very different from corruption not because it has a different effect on the political landscape (it has the exact same effect on the political landscape), but because there are a few laws the people with capital agreed upon that enforce and justify the system. It's not a complete free-for-all, there is a particular process to it, but that's because even those who are functionally corrupt aren't complete savages and like a little nuance with their definitely-not-criminal activity. Also by having at least *some* laws on the books it helps them point to it anytime someone calls it out as bullshit. \"Hey, we aren't corrupt, we aren't breaking the laws we created!\"", "Partial solution: no campaign advertising is allowed other than in a government provided booklet and .gov page available to all voters explaining your positions/ideals.", "There is no difference, its legalized bribery because thats what corporations (and politicians) want. because more $$$ is better than less $$$ you dont need me to explain that one right? thought so.", "lobbyism is the number one reason that democracy fails. for instance lawmakers are supposed to regulate finacial institutions and keep their power over society in check. how are they ever going to achieve that, if lawmakers are depended on finacial support from those finacial institutions they are to make regulatory laws for!? the media doesant get invited to back office deals! anything could be going on, anything could be standard practise!", "Lobbying as an individual person, acting independently of any business interests is so rare. What its actually turned into is corporations (who are legally treated like an individual) and other PAC (political action committees) donating lots of money to politicians to get legislation passed in their favor. In my opinion, there is really no difference in how lobbying is actually being practiced in America right now and corruption. Somehow it is being allowed because they have found numerous loopholes to cover their asses in the event of a lawsuit or any other scrutinization.", "Lobbyism wasn't always the norm. It is just the way civil society is structured these days. Before the 1960's, 'interest groups' (as you would call them) were composed of federations of people that worked together to advance their mutual interests in policy. During the civil rights movement, however, new more efficient strategies were invented to accomodate for the fewer resources and manpower among minority groups such as women and African Americans (because the federations were generally segregated). These strategies were much more efficient. Think the NAACP, an organization of 'experts' whose salaries are paid through donations. The problem is that these organizations were too efficient, and their use has spread considerably. More organizations are utilizing this rent-structure funded by grants from corporations and wealthy donors. The consequence is that these organizations disproportionately are at odds with the middle class and are more beholden to the wealthier segments of society. This is 'corruption' because it goes against the notion of popular jurisdiction by granting unfair advantages to a select elite."], "text_urls": [[], [], [], [], [], [], [], [], [], [], [], [], [], [], ["http://www.npr.org/sections/money/2017/03/22/521132960/episode-760-tax-hero"], [], [], [], [], [], [], [], [], [], [], [], []], "score": [3505, 2498, 541, 304, 112, 69, 55, 54, 52, 23, 22, 20, 15, 15, 14, 6, 5, 5, 5, 4, 4, 4, 3, 3, 3, 3, 3]}}, {"q_id": "62btz2", "category": "Repost", "title": "How can a VPN hide your browsing history from your ISP if all of the data still passes through their network to & from your computer, and they know exactly who they're supplying internet to?", "title_urls": {"url": []}, "selftext": "I understand how it masks your IP from the rest of the web, but doesn't your ISP still know exactly who they're providing internet to? Data is still going through their lines to reach your computer. They know I subscribe to my internet service. I'm sure they also know my device's MAC address/other identifying information.", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfldfhn", "dflc64i", "dflgfpg"], "text": ["Imagine that you want to send a note to your friend Sally, but she's too far away. So you have your friend Nosy Ned deliver it for you. Only problem is that Nosy Ned is, well, nosy. You know he's going to read your letter, and probably post it all over Facebook. So instead you write \"The narwhal bacons\" on a slip of paper and pay Nosy Ned to give it to George. And Ned reads it and thinks, \"WTF?\" Meanwhile, George receives the letter, looks up the code on his cheat sheet, and writes down, \"Meet me at the library.\" He delivers it to Sally, who writes a response: \"2 pm.\" George uses his cheat sheet again to encode the message as, \"at midnight,\" and gives it to Nosy Ned to return to you. Ned, of course, peeks, and again is like, \"WTF? Why are these two idiots talking about narwhals?\" Nosy Ned is your ISP, and George is your VPN. Everything that goes between you and the VPN is gibberish. Your ISP knows you are sending a coded message, but they can't read what it says. And everyone else only sees the massages George relays; they don't see you relaying it. Of course, you still have to trust your VPN is not selling your data.", "A VPN will have an encrypted connection between the VPN server and the client. As a result, the only thing the ISP can see is that you are using a VPN, they must be able to read where to send the data to, therefore the IP address of the VPN server remains unencrypted, but the contents of the message is secure. During a normal web request like accessing reddit, it is similar, the connection itself is encrypted, but they know you are going to URL_0 since you are sending packets to reddit's servers. Once the VPN connection reaches the VPN, it is both a) probably in another ISP's network, therefore not something your ISP can access, and 2) unknown which VPN client is sending sending out which data since multiple VPN clients are connected to one VPN server and the ISP cannot tell which packets that go and access webpages and the general internet correlate to which of the VPN clients.", "**Regular internet access** *Browser*: May I please get the website from URL_0 ? *ISP*: logs that customer A wants to go to URL_0 and then sends request to URL_0 *Reddit*: Oh, here ya go buddy! I'll encrypt it for you. *ISP*: Logs the fact that URL_0 sent encrypted data back to customer A and then sends them the data. *Browser*: Sweet here's the data from Reddit. **VPN** *Browser*: May I please get the website from URL_0 ? *VPN software on computer*: Sure *ISP*: cvape[rutcfe54ctujhf7te5yt98w745nc78yvb874gpm245j2hgu logs the fact that customer A sent some unknown encrypted data to the VPN *VPN*: Oh snap that dude wants URL_0 , Reddit may I please have? *Reddit: Hey VPN Server, here's the data from URL_0 let me encrypt that for you. *VPN*: Thanks Reddit! I'm gonna send this back to the guy. *ISP*: phc8f5yt04985yffg74358hf47383478cb4783gb & ^$%$* & T*G & gv logs the fact that VPN sent some unknown encrypted data to customer A *VPN software on computer*: Beep boop beep here's the data from URL_0 *Browser*: Here's URL_0 **So you see....** The difference is that with regular internet access, your ISP can see the websites you visit. With a VPN all they can see is that you are sending encrypted data to a VPN server and getting encrypted data back from the VPN server. Also the ISP that the VPN server uses sees a whole bunch of requests but they don't know who each request belongs to so they can't really package that data in a useful way."], "text_urls": [[], ["reddit.com"], ["Reddit.com"]], "score": [6, 4, 3]}}, {"q_id": "62d722", "category": "Repost", "title": "So whats up with Congress and their browsing data.. why does everyone want to buy them?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dflkntv"], "text": ["Congress were scumbags and sold out the us public. New law says your ISP can record and sell your browsing data. They want to buy congressmen browsing data to find gross or encriminating or dumb searches"], "text_urls": [[]], "score": [5]}}, {"q_id": "62e3h9", "category": "Repost", "title": "Why do you get heavier when you go \"limp\"?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dflrbk2", "dflrcjh", "dfltc7n"], "text": ["You don't. What makes it harder to lift someone when they go limp is basically about finding a good hand hold that provides a level lift. If you have to use extra strength to grip them, that's strength you can't use to lift them.", "You don't get heavier, you get more unwieldly. By being a weight with a shifting center of gravity extra effort is required to keep the weight steady rather than sliding off to the side.", "It's the same reason why you can't lift as much weight using barbells/dumbells as you can using a weight machine: you're forced to use stablizing muscles to balance the shifting center of mass, and therefore can't use as much strength to do the press/pull."], "text_urls": [[], [], []], "score": [16, 10, 10]}}, {"q_id": "62g9v1", "category": "Repost", "title": "When our internet history becomes widely available for all to see, what actually links it to a person's identity?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfmd2o1"], "text": ["Well, it depends on where it becomes \"Widely available\" but I'll answer in all cases. Also, this is how *I* understand it. You use an ISP (Internet service provider). This is a company that connects you to a server your computer is trying to reach. In the process, your ISP may or may not record your public IP and what it's trying to connect to. This isn't *your* specific history, this is the history of essentially whatever your specific modem requests. Since multiple people could be connected to the same line that uses a single public IP, it's impossible to tell exactly who is requesting what. That could only be known by your router. Your router assigns each of its connection a private IP. It would normally be 192.168.num.num and is specifically for private networks. Your private IP cannot be seen by your ISP. So, the only entity that could have your internet history is your ISP *if* it's been logging what you visit. Some are more honest than others. Because even if you visit a website and type all of your information in, someone will know that *that* specific IP is you but they will only know that you visited *that* specific site. They don't know what other sites an IP has visited because that kind of information isn't exchanged between server and computer when you connect to a website. Google chrome or internet explorer knows since it records the sites you've visited. But even your ISP doesn't know since you're using a public IP and there may be multiple people using the same connection. Meaning, at most, they'll be spying on a group of people, not one specific person. Now a \"man in the middle\" attack is essentially the only reliable way of knowing what a specific person is visiting. It would also have to be based on your router. Essentially what they would have to do is connect to your router and \"sniff\" the packets that your private IP address is requesting (what your computer/phone/tablet is requesting). There's an easy way around this although not 100% fool proof. A VPN, virtual private network, or proxy. Essentially what this does is connect you to a VPN's server and request sites from there. Basically, the only thing someone spying on you would see is that you're sending requests and info to one address constantly, the VPN server. Usually, if it's a good VPN, this info is encrypted and only you and the VPN server can decrypt it. Your computer essentially asks the VPN server to connect you to whatever you're trying to reach. Be warned though that the VPN provider could be recording your history (I believe it's a law to do so in the UK). A good VPN could promise it won't but you can't really know. It's still good protection from essentially anyone who isn't very powerful, but you can never *know*. EDIT: A good VPN I use is CyberGhost 6. I believe you could use it for free or you could go premium. VPN providers need to pay property tax, maintenance, and electrical bills for their servers so normally a good VPN is one that you pay for. Not one that is influenced by who it advertises since the only other way a free VPN could pay to keep its services up and running is through Ad revenue. FURTHER READING: Now, very powerful agencies like the FBI have methods to identify to a certain degree of certainty who you are and what you do online. This has to do more with psychology than hacking. Psychological patterns, ways of typing, etc can give them an idea of who is doing what but cannot definitively prove who a person is. It could only really be used to spy on someone and possibly lead to an interception of an illegal package for instance which will lead to an arrest. You can't really be anonymous if the FBI or some other major government agency is targeting you. But from hackers, corporations, etc you can to a good degree with a good VPN using a good VPN. If you're *REALLY* drop dead paranoid, use a VPN to connect to another VPN. Meaning the only thing your first VPN provider knows is that you requested to be connected to another VPN and the only thing your second VPN provider knows is that sites are being requested from your first VPN provider's server. I feel like I'm nurturing an unhealthy amount of paranoia in the minds of people who think they'll ever need to use this haha."], "text_urls": [[]], "score": [3]}}, {"q_id": "62gjdz", "category": "Repost", "title": "when reading weather reports and it says 50% chance of rain, what does that actually mean and how is it calculated?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfmeyuy"], "text": ["It means that in all cases that look like what we see now, 50% of them will end up with rain, and the rest will end up without rain. It's based on two things: looking at past cases that resembled today's situation, and running a computer simulation that mathematically shows how weather works."], "text_urls": [[]], "score": [5]}}, {"q_id": "62h08w", "category": "Repost", "title": "Can y'all simplify what's happening with/about/around Devin Nunes?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfmj16c"], "text": ["He is Chairman of the House Intelligence Oversight Committee. In that position he would be resopnsible for looking into allegations of Russian interference with the 2016 election and any collusion in that interference by Americans, particularly Trump staff/surrogates. He as steadfastedly refused to look into this, and instead has tried to deflect attention away from it by claimin to have secret information supporting Trump's twitter allegation that \"Obama had Trump Tower wiretapped\" which, rather than share with the other members of h. s committee, he instead rushed to the white house to share with Trump staffers. And now it turns out that Trump staffers are the sources of that still unreleased and unshared information to begin with."], "text_urls": [[]], "score": [3]}}, {"q_id": "62iewu", "category": "Repost", "title": "How was coding first invented without a coded thing to run what was being written?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfmtv91"], "text": ["One of the early programming methods was punch cards. You would punch a hole in a card or a long sheet of paper. The holes in the cards would turn circuits on or off, which was used to send 1's and 0's to a computer."], "text_urls": [[]], "score": [3]}}, {"q_id": "62ivnt", "category": "Repost", "title": "what is the difference between a president and a prime minister?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfmyk6d"], "text": ["Presidents are elected directly by the people in a vote. A prime minister is the head of the party with the most seats (or head of coalition of parties) in parliament. The PM is not directly voted for by the people, rather is selected by the party (but typically done in advance of elections so peeps obviously know who will be PM if any given party wins the most seats). Typical parliamentary system you just vote for your local MP (and local senate member if applicable). IMHO the most significant consequence of the difference is that with a prime minister you know the head of state likely has legislative power, bc his or her party is the largest. With a president it could be a lame duck in terms of being able to implement policy. Edit: and some places have both, with varying divisions of power."], "text_urls": [[]], "score": [3]}}, {"q_id": "62k7bm", "category": "Repost", "title": "Why is, let's say 50 dollars written like $50 and not 50$?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfn7104", "dfn7elm", "dfnaa2i", "dfn9kfi", "dfn7chc", "dfnalff", "dfncl60", "dfnamoq", "dfncjmj"], "text": ["Back in the day, when books were kept physically in paper books you would write $1,000.00 in the ledger, because it makes it harder to modify the entry. If it was written as 1,000.00$ it would be easier to forge it to become, for example, 91,000.00$ by appending a single digit in front. It's the same for say, the thousand separator which separates groups of digits in three so that not only they're more easily readable, they make even changes from say, $1,252,001.- to $1,2152,001.- easily detectable. Source: I dunno, googled some and this here was an explanation that more or less sounded sound.", "Different countries have different ways of writing their currency symbols. Some write it before the number, some after. Generally, people write it a certain way because that's how people before them wrote it. In the US we write the sign before the number because that's how the British wrote the pound sign before us. There are many benefits to writing the $ before the number. It makes it harder for forgers to modify numbers. You can't change $100 to $2100 by adding a number because there's a dollar sign in the way. Also it's easy to read the difference between dollars and cents on a sign, because the cent sign is written after the number. It's written like $3 and 50\u00a2. Also if you wrote an amount as a decimal, 3.50$ the dollar sign is next to the cents values, and that could get confusing. But there is little to no evidence that any of these were the reason that way of writing currencies became standard. Language, symbols, and writing systems are constantly evolving, and their origins are too old to know with any certainty. People tend to keep doing what was done before unless there is a good reason to change. That's why we write the dollar sign before the number. Any more specific explanation is speculation at best.", "The short answer is \"history\" and the slightly longer answer is \"nobody really knows.\" The US uses the English convention for writing currency symbols: the symbol of the primary currency unit goes before the number. So it's not just $50 but also \u00a350, \u20ac50, \u00a550 etc. Other languages do this differently, so saying that it's to reduce forgery seems like pure speculation: there is no good reason to suppose that only English-speaking businessmen saw a greater need to reduce forgery in this way.", "Not an answer , but still relevant. In French, the dollar sign is always after the amount. In English $123.45 In French 123,45$ I have no idea why the English put the sign first. [ Edit : When I wrote 'French', I meant 'French Canadian' ]", "I can't find anything concrete to confirm it, but I think it may be something that English borrowed from Latin and then stuck with. Certainly the symbols for pre-decimal British currency are derived from Roman currency. Some (most?) other languages put the currency symbol after the number.", "Then the question becomes, why don't we say \"Dollars fifty\"?", "Because the fact that the dollar sign ($) means end of line in a regular expression, hence one regular expression for matching 50 dollars would be [0-9]+\\\\$$ rather than \\\\$[0-9]+$ which is clearly and objectively more ugly.", "I understood it to be written like that to provide a frame of reference for the number. I.e. $ 50 - so the currency is Dollar, and there are 50 of them. Otherwise, you are almost qualifying the number by its definition after the fact and I agree with the other comments, making it harder to add an extra number or two in front of the actual figure.", "Fun Fact: The dollar sign originally came about by superimposing a \"U\" on an \"S\" (for US). People then got lazy and made it two vertical lines instead of a U, and got even lazier by putting only one vertical line. The more you know."], "text_urls": [[], [], [], [], [], [], [], [], []], "score": [1482, 724, 21, 17, 11, 9, 7, 4, 3]}}, {"q_id": "62kfzu", "category": "Repost", "title": "If my ISP starts selling my browsing history, will everyone on our home wi-fi start getting porn click bait and cock ring advertisements?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfn9ibi", "dfn9ppj", "dfnb150", "dfn8w09", "dfn9llb", "dfna9r7", "dfnavy6", "dfnariq", "dfn9jaw"], "text": ["Not really. A lot of ad services specifically will not advertise \"adult content\". This is for a number of reasons, but one is that most sites don't want to be seen with that kind of advert. For the same reason, most advertisers will go to ad services that prohibit use on 'adult' websites. This is what really leads to the difference in ads on adult and non-adult sites. You won't likely see any ads for 'horny girls in your area' where you hadn't before, because they aren't really targeted at anyone.", "Sorry if I'm a lot off-topic but how do VPN's factor into all of this? Are there ways for them to still track our history if we use them?", "Want to know the fun part about this? This is repealing a bill that hadn't even been put into effect yet, your ISP has already been doing this for a long time.", "If it's any consolation, if it does happen they don't have to know it was because you where on porn, plus, your dad watches porn so there's that", "The way Internet Service Providers are gathering your internet history is by simply tracking what websites you request and what is delivered to your network. If you request to see URL_0 then the ISP will see your request and route the traffic accordingly. And now they log that you requested URL_0 and can legally sell that to anyone buying. If they can see which individual computer is the one requesting the website is another story. It depends on how far ISPs implement in order to gather your history. If they have router access, Which is likely, than they can see which specific computer requested to see those luscious videos. I believe this is a logical concern. But I do not think it will be a problem. As ISPs will likely have some sort of identifier (Say a local IP or MAC Address) for who wanted the traffic and target that person individually. It wouldn't make sense if sharon wanted shoes and they send bob some lovely coupons on his next pair of high heels. The targeted advertising wouldn't be effective then.", "well first this is something that has been going on for a long time already and a they don't really need your history. A lot of ad services can track you by your ip address and serve up relevant ads to you across multiple sites and devices. That said though there are limit's like you shouldn't be seeing porn ads show up on walmart for example and most porn sites are basically on \"fringe\" ad networks because many reputable advertisement company's / brands don't want to be associated with those sites for the most part. Long story short is you really should only be getting porn ad's on porn sites or super shady sites.", "Related question: Can my ISP sell my browsing history to my employer?", "This is why i use tor for porn. Its slower and buffers more, but its less likley to leak my fetishes.", "I have a question too. Is this similar to what Google already does to me? For instance, if I look up a tent on the internet I will receive adds for tents on the sidebar of websites for weeks. How is this ISP sale different?"], "text_urls": [[], [], [], [], ["google.com"], [], [], [], []], "score": [92, 32, 27, 12, 9, 7, 4, 3, 3]}}, {"q_id": "62ln77", "category": "Repost", "title": "How and why is HTTP not secure (vs HTTPS)?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfnhe06", "dfnj03x"], "text": ["There are lots of ways. But anyone that owns any question you are communicating with or through, they can capture and copy and view anything that passes through their equipment. If you are communicating wirelessly, then that is even easier. Anyone on the same wireless network as you are can just listen to whatever it is your computer is transmitting.", "If you send data over an unencrypted connection, anyone who inserts themselves into the network between you and the intended recipient can see what you're sending. For example, if your laptop is connected to a network that I control, and you go to an unencrypted web site and you log in on that web site, your laptop's browser basically says, in plaintext \"hi website, i am 16o1denRatio and i want to log in, and my password is \"greatpassword123\". If I have the right equipment connected to that network I control, I could read all this data as it passes through the network and leaves for the internet. I now know your password. If this is a wired network, it requires me to have access to the cables and network equipment if I want to do this, so it requires a bit of work. If this is a wireless, unsecured network, such as for example at starbucks, every laptop (or phone) can see what every other laptop is sending and receiving (because the radio waves from the wifi router are sent in every direction, not just in a straight line to a particular device). However, all these devices are normally set up to ignore all the information they see that isn't addressed to them, but there are ways to make your laptop stop ignoring data that's not meant for it, and then I would be able to read everything that every Starbucks user sends and receives, unless the websites and apps they use encrypt the data before sending it (and of course also only receive encrypted data). If a connection is encrypted, even if you have the ability to see the transmissions, the data in the transmission will just look like garbage (like when your laptop sent \"my password is greatpassword123\", to me it would just looks like \"jj5#\u00a4%dsdjflsk%\"gg34\"), instead of actual usernames, passwords, or any other readable data."], "text_urls": [[], []], "score": [3, 3]}}, {"q_id": "62mdxn", "category": "Repost", "title": "Why do public toilet seats always seem to be horseshoe shaped but home toilet seats are complete circles?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfnxlz6", "dfnozxb"], "text": ["Also, if you realize you did not lift the toilet seat whilst peeing, the gap will act as a passage for your pee so you can still lift the toilet seat up without having to hold your pee in.", "Right from the Toilet page on wikipedia, apparently it's so folks can wipe from the front without having their genitals touch the toilet. > The purpose for this seat design is to allow women to wipe the perineal area after using the toilet without contacting the seat. It also omits an area of the seat that could be contaminated with urine, and avoids contact between the seat and the user's genitals. I suppose because public toilets are bound to be dirtier than your own - plus you have a much better idea of the last time your own toilet was cleaned. I've seen plenty of home toilets with the split fronts as well though."], "text_urls": [[], []], "score": [3, 3]}}, {"q_id": "62mymp", "category": "Repost", "title": "can someone explain how I'm \"wasting water\" when I'm turning my faucets on?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfns9j5", "dfnslk5"], "text": ["All of that process uses energy and resources. Your individual excess water usage might not really matter but if millions of people are doing that, that's heaps of resources devoted to making some noise while you brush your teeth. Also depending on where you live fresh water might be scarce and letting it run for nothing (again multiplied by everyone in your city) is a huge volume of water used for nothing.", "Water isn't generally recycled, it gets cleaned up a bit and is then dumped in the ocean or a river which ultimately carries it to the ocean. It may be used for purposes such as cooling power plants, in order to conserve fresh clean water, but it's not going to come back out of your tap anytime in the near future, not till it's ultimately run off to the ocean and evaporated to fall on the land as rain again. URL_0"], "text_urls": [[], ["https://water.usgs.gov/edu/wuww.html"]], "score": [7, 5]}}, {"q_id": "62o0um", "category": "Repost", "title": "How did language begin, and how did we assign words to stuff?", "title_urls": {"url": []}, "selftext": "Back when using words to communicate was a new thing, how did those people first assign words to stuff and let others know that a certain word meant a specific thing? For example how did the very first humans to use the word \"love\" communicate to the other person what they meant by that word?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfo1410"], "text": ["Oh, if only anthropologists and linguists could go back to that moment and see how it happened! But they can't, so we have to speculate based on incidents we have been able to observe. One of my favorite stories to talk about for this example is the birth of Nicaraguan sign language. Back in the 70s, deaf people had no centralized education. They were isolated from each other and had no means of communication. In the late 70s and early 80s they started putting deaf children into a special school and trying to teach them spanish and lip reading. It didn't go very well. But something remarkable happened. The kids basically invented their own sign language to start communicating with each other. The adults had no idea what they were saying so they brought in some linguistic experts to figure it out. It started as a simple pidgin, but over a few years, the students evolved it to a full language with verbs and verb tenses and other complex patterns of speech. This example is often used as evidence that language is something that's just hardwired inside of the human brain. That our brains just work that way. So if the human brain just works that way, then you have to go back to speculate about how earlier humanoid species might have started using language to get to your answer."], "text_urls": [[]], "score": [5]}}, {"q_id": "62oqqp", "category": "Repost", "title": "Please explain Unitarianism in the simplest way possible.", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfo80zs", "dfoex91", "dfoghiz"], "text": ["There are two fairly distinct movements that call themselves \"Unitarian\". The first refers simply to any Christian movement that rejects Trinitarianism (the belief of one God in three Persons), Binitarianism (one God in two Persons), or any of the other Christologies that view God as anything other than an absolutely single entity. The more common meaning today refers to the Unitarian Universalist Association, its members, churches, and philosophy. They are a movement that was originally Unitarian in the Christian sense above (and also Universalist, meaning they believed everyone went to Heaven), but now rejects any one religious doctrine in favor of a philosophy of \"recognizing the inherent worth of every human\" and \"supporting everyone's search for meaning\".", "Simplest? I'll do my best: There is one God. Jesus was a good human dude. Not god People are basically good, and they can choose their destiny, but can and do often choose evil, which is a real thing. The Bible is cool, but not perfect. No one religion is all- right. No one creed is perfect. Hell? Meh..... Be kind.", "The way I always heard it when I went to a Unitarian church is \"God is one and not a trinity; Jesus was man and not divinity.\""], "text_urls": [[], [], []], "score": [12, 8, 3]}}, {"q_id": "62r3o0", "category": "Repost", "title": "What is the point of a conductor in an orchestra when everyone knows what they are playing?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfonkxm", "dfoq2ee", "dfot0y1", "dfonh72"], "text": ["Everyone knows their parts and can play it nice on their own but once you have to coordinate a complex piece of music with lots of other musicians it can be very hard. First of all sound takes some time to travel from one side of the stage to the other. So if you were to base your tempo on someone across the room you will be off and it will sound horrible. So you need to use visuals to find the tempo as light travels much faster. This is why the conductor swings his arms in beat with the music. But there is also a lot of other things that is different each time you play a piece. The performers are in different states of mind, the instruments might be affected by temperature and humidity, the sound changes depending on the room, the audience act differently, etc. So the conductor is \"playing\" on the performers as if they were a big instrument. If one section of the band is too loud he can tell them to bring it down, if someone gets out of beat he can tell them to they are ahead or behind, some pieces have sections that is deliberately changing beat or does not have a beat and it is up to the conductor to find the right timing, etc. Basically if you have a large group of musicians you need someone to coordinate them to make great music.", "In addition to keeping it all together during a performance, most of the hard work a conductor does is during the preperation that leads up to the performance. It is the conductor that usually decides and applies what the musical details are.", "Explainations here are very good, and I would like to add that the conductor may look useless during the representation, but s.he's responsible from how the final piece will sound like. An example of the choices made by the conductor to change the sound of a piece can be heard in the difference between the interpretations of the same Mozart's Requiem Lacrimosa, [one from Celibidache]( URL_3 ) and [one from Bernstein]( URL_0 ). Apart from the speed, you can notice that the violin \"response\" melody at the beginning of the movment is much louder in Berstein's, and that it has a lot of room to 'express' : you hear it a lot more than in Celibidache's. The *qua resurget* from Berstein sounds way more split, probably because of the slower pace, but in the the following *lacrimosa dies illa*, you can hear the alti louder in Bernstein's (this is a faint difference, but still). Another example is the baryton's entry at 34:48 on Celibidache's version (36:31 for Bernstein) : they acentuate the first note, then the next one is lower. This creates more movment than in Bernstein's, where the two note are sung with the same power, adding to the 'rigorous' moment. At the opposite side of the spectrum, the same moment in [collin davis's version]( URL_2 ), the men sing at the same level all the time and the other voices are forced to sing louder to be heard (notice that in Celibidache's, the men go lower so we hear the alti and tenors). That's one of the many examples you can give (and they're just in 2 minutes extracts !). Try to listen to two different versions of the same piece (why not Beethoven ? [one]( URL_1 ) and [two]( URL_4 ) ). Listen to the different paces, and the crescendi at around 10sec into the 5th symphony. (btw Duhamel conducted tthis year's New Year concert in Vienna, and it may be cool to compare the Radetzky's march versions over the time). You could try the same with different versions of the Star Wars theme, too, comparing professional orchestras to local schools playing it and try to notice the differences)", "Helps keep everyone on beat, cues different groups in (if you have to count like 80 beats of rest and miscount) I think most important is the conductor directs the expression, phrasing, etc of the music. How loud to get, how quickly you want to get loud. What melodies should be heard more and which ones softer. Oh yea, and when to stop playing!"], "text_urls": [[], [], ["https://youtu.be/m3wFdajeAwU?t=33m14s", "https://www.youtube.com/watch?v=OGnBrabqdP4", "https://youtu.be/D95igow6I6g?t=30m42s", "https://youtu.be/_9vuUJcUbkE?t=31m44s", "https://www.youtube.com/watch?v=MKjX5u1p4mc"], []], "score": [76, 8, 8, 6]}}, {"q_id": "62unxb", "category": "Repost", "title": "What happens if you turn on a lamp in a vantablack room?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfp9dny"], "text": ["It would look like a flat black background with a lamp in front of it. Sort of like [this]( URL_0 ) only without the dangling lamp parts being visible if they were painted Vantablack."], "text_urls": [["http://more-sky.com/data/out/4/IMG_36696.png"]], "score": [8]}}, {"q_id": "62vt39", "category": "Repost", "title": "Why do you get something like a bright vision when you rub your closed eyes?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfpgoqm"], "text": ["Nerves can be stimulated by many things. Some are built to trigger when they get hot, or hit by light, or touch a certain molecule. No matter what it is, the nerve will send the same signal to the brain. The brain interprets the signal based on which nerve brought it. Imagine two babies, one in a red hat and one in a blue hat. The red one cries when it's hot and the blue one cries when it's cold, and the cries sound the same. However, you can determine the temperature of the room based on which baby is crying. The nerves in your eyes that are activated by light can also be activated by mechanical force, ie, rubbing. Imagine if the red hat baby also cries if it was being spanked. If someone spanked the baby and you saw it crying, you'd think the room is hot, even if it isn't. This is what is happening with the brain. It detects signals from the light receptor nerves and interprets them as incoming light. You'd get the same effect if you rubbed your open eyes, but there would be obstacles. First, lots of real light is coming in, which would overshadow the false lights. Like a speaker blasting heavy metal in the baby room. If you were in total darkness, it would also hurt and you'd be too preoccupied to notice the false lights. Like if the microwave went off, signalling the completion of your hot pockets. Would you go an tend to the babies when there are hot pockets waiting to be eaten? I didn't think so."], "text_urls": [[]], "score": [3]}}, {"q_id": "62whn8", "category": "Repost", "title": "How is the calorie content in food and drinks determined?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfpln0i"], "text": ["I've heard of three methods. The first is to burn it and see how much heat it produces. This is basically what the body does except that we use enzymes to control the burn rate. In labs they burn it in an oxygen rich environment in a sealed insulated container. This will give you a good measure of the total calories in food. The second is to feed a lab subject carefully measured quantities of food and to regularly weigh the subject and their feces while monitoring their physical exertion. Then we can back calculate the calories from the relationship between these measures. This gives you a good measure of how many calories humans absorbed from food. Finally for some foods we just add up the calories in the ingredients. This has the advantage of being significantly easier than the other two."], "text_urls": [[]], "score": [10]}}, {"q_id": "62xxyu", "category": "Repost", "title": "What stocks are", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfpwfuc"], "text": ["A share is a piece of a company that you can buy. Stocks are just all the shares without regard for which company they belong to. You can buy a share of a company and sell it later. That's the primary thing most people think about when they're playing the stock market. If that share's value goes up, you can turn a profit by buying it when it's cheap and selling it when it's expensive (\"buy low, sell high\"). Unfortunately, you don't know if a stock will go up or down, so you're playing a bit of a guessing game. Shares rise in value if the company either did well in the last fiscal quarter (in the last few months) or is predicted to do well in the next fiscal quarter (in the next few months). There are tons of other things you can buy and sell that aren't stocks on the stock market, and different ways of buying and selling everything, but I'm just giving the very basics here. If you want to know how to get started, you should look it up in /r/personalfinance or similar. Someone has probably already asked how to get started, so you can just look for that thread."], "text_urls": [[]], "score": [3]}}, {"q_id": "63071u", "category": "Repost", "title": "If you were in space without a suit - what would kill you first - the pressure difference, temperature, lack of oxygen, radiation or something else?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfqbvro", "dfqaklg", "dfqvfqt"], "text": ["Lack of oxygen to the brain would kill you first. How you get there is a bit complicated. You can make your last few moments a lot more painful by trying to hold your breath, as your lungs and your body can't handle the pressure of gases inside your lungs trying to escape into the vacuum outside, causing very violent damage to lungs and surroundings. Because the estimated time you have to live in space without a suit is measured in seconds or minutes, I'm not exactly sure if it would dramatically shorten your lifespan, but it would make rescue almost impossible, and it would most certainly be really painful. So assuming you're not holding your breath, you would have maybe 10s before you lose consciousness. After this, lack of oxygen and various problems related to pressure or lack thereof would kill you over the course of maybe 2 minutes. My sources estimate that if you're rescued up until 90s after entering vacuum, you have fairly good chance of walking it off, but any longer than that and your odds of survival are dropping fast. So maybe 2min before lack of oxygen kills you. If you were not under direct sunlight(finding a shade in space may be difficult, but lets say you managed to find one, otherwise your might never freeze), you would die of hypothermia within a couple of hours. Because lack of oxygen kills you in less than 2 minutes, this isn't really relevant. If you were under direct sunlight, you would not necessarily freeze at all, and instead you'd have to worry about really severe sunburns. Radiation would not kill you, probably. Your risk of getting cancer would increase slightly, but onset period of cancer would probably be measured in decades. Even if you got terribly unlucky, it's hard to see how you could die of radiation in less than a year of space exposure. Sources: URL_1 URL_0", "If you tried to hold your breath your lungs would likely rupture, killing you in a few seconds. If you exhale before leaving the ship, you've got about 15 seconds before you pass out, and then a couple minutes before you die from lack of oxygen. Everything else would take longer to kill you.", "Some of this happened to a NASA volunteer subject in 1966 when he was accidentally depressurized in a test chamber. In a zero-pressure environment, gases come out of solution and water evaporates. He lost consciousness in about 15 seconds because his blood was rapidly de-oxygenated. In air you can last 2-3 minutes without breathing because it takes that time use up the oxygen that your blood is carrying. You'd get some ice in your airway from evaporative cooling. When a liquid evaporates it takes some heat with it. You can demonstrate this for yourself if you get a can of compressed air, turn it upside-down, and spray it on something. The liquid inside (which isn't air at all but that's for another day) sprays out and immediately evaporates, leaving a little bit of ice wherever it landed. Apart from your mouth, nose and throat, the rest of your body would take some time to get cold because a vacuum doesn't conduct heat very well. Water in your soft tissues would start to evaporate and you'd swell up like the Michelin Man. From animal studies, it appears you can survive if you're put back in a pressurized environment within a minute and a half, before your heart muscle is seriously damaged. The point about lungs rupturing would be an interesting experiment if you could do it without dying. It is true you can do that to your lungs coming up from a deep SCUBA dive but that involves pressure differences of a few atmospheres rather than the one-atmosphere difference between space and your space ship. It might depend on what you were doing with your chest wall and diaphragm. Your chest withstands substantial pressure differences between inside and outside every time you blow up a balloon and there are people who can blow up a hot water bottle to the point where it bursts. As for radiation, if you were on your way to the Moon or Mars you wouldn't be protected by Earth's magnetic field and if you were REALLY unlucky you could get caught in a storm of charged protons that could cause radiation sickness, but of course you'd be dead from hypoxia before that. According to [this NASA page]( URL_0 ) \"Between the Apollo 16 and 17 missions, one of the largest solar proton events ever recorded occurred, and it produced radiation levels of sufficient energy for the astronauts outside of the Earth's magnetosphere to absorb lethal doses within 10 hours after the start of the event. It is indeed fortunate that the timing of this event did not coincide with one of the Apollo missions.\""], "text_urls": [["https://en.wikipedia.org/wiki/Space_exposure", "http://www.geoffreylandis.com/vacuum.html"], [], ["https://srag.jsc.nasa.gov/spaceradiation/What/What.cfm"]], "score": [15, 11, 3]}}, {"q_id": "631lnw", "category": "Repost", "title": "Why does inbreeding only cause disadvantageous mutation?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfqldat"], "text": ["It doesn't cause them. It exposes them. We all have mutations, but we also have two copies of each gene. They are called alleles. If your parents are not related, it's unlikely they will have the same bad copy. If they are related, they could have both inherited the same bad allele from their shared ancestor. Mutations usually result in losing that gene's normal function. As long as you have one good copy, you do fine. If you have both bad copies (the same mutated version) you're SOL."], "text_urls": [[]], "score": [4]}}, {"q_id": "632rj8", "category": "Repost", "title": "how do cell phones make calls when they don't have a sim card or any carrier attached to them?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfqv33e"], "text": ["When you have no sim card inserted, the phone can still connect to nearby cell towers however you'll get a no service notification because whichever network the cell tower belongs to is refusing connection since it can't tell what network the phone is linked to. In the United States all carriers are required to connect any 911 calls regardless if the call is coming from a phone in the carrier network or not. Even if there's no service or you don't have a sim card your phone can still call 911 unless you're in the middle of nowhere."], "text_urls": [[]], "score": [9]}}, {"q_id": "63611g", "category": "Repost", "title": "How did the earliest humans know how to reproduce?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfrkuey"], "text": ["Yeh it was instinct, in the same way sexual animals know how to reproduce. They saw a pretty stone girl and wanted to put their penis in them, and hey presto!"], "text_urls": [[]], "score": [7]}}, {"q_id": "63a7a2", "category": "Repost", "title": "Is some sort of time travel possible if humans are able to move almost as fast as the speed of light?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfshhoo", "dfsh5as"], "text": ["Theoretically, yes. A human could effectively \"move into the future\" relative to other humans. Time is experienced more slowly at higher speeds (\"time dilation.\") The effect ramps up sharply as one approaches the speed of light. At 2/3 the speed of light it's only about 34% slower, but at 99% of light speed it's over seven times slower, at 99.9% almost 23 times slower. So, let's say we find a brave ~~astronaut~~ chrononaut who gets on a spaceship, flies away for six months at 299,500 km/s (99.9% light speed) then six months back at the same speed. He would find that almost twenty-three years had passed on Earth, with his friends and family considerably older, yet he would only have aged a year. For my money, that's time travel. Practically speaking, mass also increases sharply as one approaches light speed, so getting up to relativistic speeds isn't easy. Relativity corrections do have to be made to GPS satellites, which go fast enough to experience time just a little slower relative to us.", "Sure, forward in time. But we sort of already have that kind of time travel - we travel forward at the rate of one second per second. But yes, if you somehow were to accelerate up to near the speed of light, and then slow back down again after, you'll have aged less than the people who did not accelerate up and down again. This is called the *twin paradox*. URL_1 URL_0"], "text_urls": [[], ["https://www.youtube.com/watch?v=0iJZ_QGMLD0", "https://www.youtube.com/watch?v=Bg9MVRQYmBQ"]], "score": [21, 6]}}, {"q_id": "63b8nn", "category": "Repost", "title": "How do we determine how many calories are in a food?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfsqq7a"], "text": ["One method is called a bomb calorimeter. It's a special device that burns food and measures how much heat the resulting fire generates. It's carefully designed to detect the energy output of just the food and not the ignition source (thing that sets the food on fire)."], "text_urls": [[]], "score": [3]}}, {"q_id": "63bnj1", "category": "Repost", "title": "How do websites detect that you're using an Ad-blocker?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfsvwij"], "text": ["When you use an ad blocker, it removes the HTML element for the ad from the page or modifies it to be hidden. The site will have some JavaScript running to check for modifications like that, and if they occur then the site knows you're blocking the ads. There are some other methods like /u/hashtag_lives_matter mentioned, but this is the most common and simplest to implement."], "text_urls": [[]], "score": [3]}}, {"q_id": "63g7qh", "category": "Repost", "title": "If all our cells get replaced every 7 years, what is keeping tattoo's so permanent?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dftttbz", "dftty93"], "text": ["The tattoo ink isn't part of your skin cells, it's literally just sitting in between cells of your lower skin layers, like [in this picture]( URL_0 ). It's like a little bubble of ink floating in a sea of skin cells. So the cells around it are constantly being replaced, but the ink is designed to be very stable and stick around, suspended in your body, for a very long time. Your body does slowly break it down, so tattoos do fade with age, but only over a long period of time.", "All your cells do not get replaced every 7 years. Neural tissues are not replaced. Bones take 10 years. But tattoo ink is placed below the skin, but above the deeper tissues."], "text_urls": [["https://s-media-cache-ak0.pinimg.com/564x/92/09/44/9209440c600006411eac12c6e1b093f0.jpg"], []], "score": [81, 14]}}, {"q_id": "63gjlk", "category": "Repost", "title": "If Every Other Major Object in Our Solar System Has a Name, Why is The Moon, just 'Moon', and The Sun, simply 'Sun'?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dftx3jo", "dftwdmi", "dftwtrz", "dftxggn", "dftx7yt", "dftz2fn"], "text": ["Moon and Sun got their names long before we knew that other moons and suns existed. The Moon was just Moon - it was a proper name, the same as Mars or Venus or Jupiter. When we found out that other planets had things orbiting them, we called them \"moons\" because they reminded us of Moon. But the proper term is \"natural satellite\". Little-m \"moon\" is just an informal term based on their similarity to big-M Moon. The same reasoning applies to other stars; you can call them little-s \"suns\" based on their resemblance to the Sun, but the proper term is \"stars\".", "The moon has a name. It is called Luna. The Sun has a name. It is called Sol. This is why we have a solar system. That we don't use the names doesn't change that.", "According to the International Astronomical Union (IAU), the official name-givers on this planet, the name of our star is Sun and the name of Earth's moon is Moon. I guess using Sun rather than The Star is a genuine name, but for The Moon, you're right. A bigger problem is that most grammar guides don't capitalize Sun and Moon, as though they don't accept the IAU's notion that we only have one of each. This seems like a grammar question, not a physics one.", "Lets go back 3000 years. Ancient people looked up at the sky and saw three kinds of things: they saw a big yellow ball, a big white ball, and lots of tiny dots. They called the yellow ball \"Sun\", the white ball \"Moon\" and the tiny dots \"stars\" (or whatever word they had for them in their languages). They also realized that a few of these \"stars\" are actually moving, so they called them \"planets\" (meaning \"wanderer\" in Greek). These names carried on over time and between languages. Fast forward to a couple hundred years ago. Astronomers realized that the planets as well as Earth are all orbiting around the Sun, and that the Moon is orbiting Earth. They also found out that the planets also have things orbiting around them - so they called these things \"moons\" as well. All these moons were given proper names, but our own moon just kept its name - *The* Moon. The same thing happened with the Sun - we realized that the Sun is a star just like all the rest we see in the night sky, so suddenly the terms \"star\" and \"sun\" became interchangeable. However like the Moon, our Sun kept its original name - *The* Sun.", "The Moon and the Sun were all named (not those particular names) before we knew of other Moons and Suns in large mass. And Earth was named when we thought the Earth was special in some way.", "Jupiter's name is Jupiter as much as the Moon's name is The Moon. Not everyone calls it Jupiter, and not everyone calls the Moon the Moon. The reason why the Moon doesn't appear to have an \"individual name\" but share its (frequently used) name with a classification of objects (moons) is because we named that class of objects for the Moon, our first representative of it. So it's not that the Moon just got an catagory name like naming a car \"car\" but the otherway round."], "text_urls": [[], [], [], [], [], []], "score": [30, 10, 8, 5, 4, 4]}}, {"q_id": "63gp3i", "category": "Repost", "title": "Why are there unnecessary and poisonous chemicals like tar in cigarettes?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfu07jf", "dfty52i", "dftxwtk", "dftxvg8", "dftyekn", "dftxvdj"], "text": ["They don't add tar to cigarettes. Tar is, *by definition*, the byproduct of combustion. So you get tar *because* you burned the cigarette. There is quite the laundry list of chemicals that *can be* added to a cigarette, though that doesn't necessarily mean it is. These fall into a number of categories: * Chemicals to increase nicotine absorption into the body. * Chemicals to increase nicotine vaporization in the cigarette. * Flavor compounds. * Fire retardants for safety. * Preservatives to increase freshness, stability, and shelf-life. * Chemicals to prevent you from getting sick from other chemicals. There's no knowing what exactly is in your cigarette as the tobacco companies aren't required to disclose their blends on their packaging, they're only required to use the approved chemicals up to their maximum safe dosages. The nicotine absorption and vaporization chemicals aren't part of some conspiracy to get kids hooked, nicotine is the active ingredient people want - the reason why they smoke - the chemical that *gets them high*. Can you believe it? People smoke cigarettes all the time, getting intoxicated by a drug, and yet they're allowed to smoke these things just about anywhere, or while operating heavy machinery. I'm not a habitual smoker, but when I do it *fucks me up*, depending on how much anywhere from a few minutes to a couple hours. So that's why they add poisonous chemicals - people want more nicotine, tobacco is going to deliver more nicotine. They don't just add it, they can't just add it, and even if they did, they need to increase the amount you can and will absorb, which, there's more nicotine in tobacco than you're going to absorb anyway, so they have plenty to work with. But here's a fun little gem: tobacco is Chernobyl nuclear-style radioactive, because all commercial tobacco in the US is fertilized with apatite, a naturally occurring mineral that is typically radioactive and used as a fertilizer. It's illegal to use it on food, but tobacco has no such restriction, and this shit is *cheap*. It makes the ground radioactive and when they switch the fields back over to food, the food becomes radioactive. How radioactive is tobacco from this stuff? Well this much I can say from experience: cigarettes are a shipping HAZMAT material *only* because of the amount of radiation they throw off. Cigarette trucks set off radiation alarms at shipping checkpoints, and release more radiation to the environment in a day than a nuclear power plant. A pack-a-day smoker receives the equivalent of 2,000 chest X-Rays a year. The recommended safe maximum exposure in a one year window for a civilian is 4. **BUT WAIT, THERE'S MORE!** If you are *utterly terrified* of radiation and cancer, you god damn should be. But if that weren't enough, let's talk briefly about \"carcinogens\". Yes, carcinogens, that lovely word we hear so often we don't hear it anymore. If you live in California especially, EVERYTHING give you cancer, according to them and their testing, right? Well here's the thing. Burning tobacco produces more than just tar, the chemical cocktails created in the tar are carcinogens. These are non-radioactive chemical compounds that absorb into your cells, come in contact with your DNA, and *rips it to shreds*. Your DNA tries to heal itself, and the errors are what we call \"cancer\". If radiation is a cute cancer puppy that just wants to love you, then chemical carcinogens are a swarm of near-immortal cancer locusts ravaging your countryside and blotting out the sun. These chemicals are *extremely* aggressive and long lived, and far more active than the radiation. If you are terrified of the radiation, then you should be shitting your pants right about now. And the dangers of radiation and carcinogens is cumulative. The longer you live, the more you're exposed to, the more likely it's going to kill you. This is why smoking around children should be a punishable crime. A couple more things: death from smoking related cancer is higher than it has ever been, even for non-smokers, even though smoking is at an all time low. See above about the children. And almost no tobacco is imported into the US, especially not for cigarettes, because if you think we put weird shit in our cigarettes, the original Indonesian Kretek can contain up to 25 mg of *rubber glue*, among other things.", "The whole \"unnecessary and poisonous chemicals\" in cigarettes is a big distortion. Any time you burn plant matter, you are going to release a bunch of toxic chemicals in small amounts, whether it is tobacco or a camp fire. That is an unavoidable part of smoking.", "Tar is a byproduct of burning plants. The same is true of carbon monoxide and many of the other chemicals.", "The tar isn't in the cigarettes when you buy it. It is created by the process of burning the cigarettes. Consuming tobacco by other means may reduce the amount of tar that would be created, or eliminate it completely.", "'Tar' as it refers to cigarettes isn't exactly what you think. It's not tar that you would use to patch a driveway, and it isn't added in. 'Tar' just refers to the resin-y (resinous?) Mess that forms from smoking product. Think the dirty black slime at the end of a joint, both are 'tar' in this sense. Wiki-Source: Tar, Tobacco Residue URL_1 Which isn't to say there aren't a shit ton (technical measurement) of additives in commercial tobacco. They are sort of necessary. Some are natural-ish (plant extracts) and some are more man made. They serve as flavor enhancers, preservatives, products to maintain moisture content, products to keep the tobacco 'clumped' properly so it doesn't reduce to powder. [Here's a list]( URL_0 ) (Wikipedia again) although it's a little light in detail of what each product is for.", "Tar comes from the burning plant matter, the other chemicals do things like make the cigarette stay burning, make it burn more evenly, or slower..."], "text_urls": [[], [], [], [], ["https://en.wikipedia.org/wiki/List_of_additives_in_cigarettes#T", "https://en.wikipedia.org/wiki/Tar_(tobacco_residue)"], []], "score": [23, 7, 5, 5, 4, 3]}}, {"q_id": "63gz83", "category": "Repost", "title": "Why is it illegal to use chemical weapons during war but it's perfectly okay to bomb, shoot, stab, drone strike and beat someone to death in the same context?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfu0kn5", "dfu3apu", "dfu4gdd"], "text": ["Chemical weapons have other issues associated with them (such as use against civilians), and beating someone to death slowly would be considered cruel and isn't typically allowed unless there was no other reasonable way to deal with the situation. Bombings might sound bad, but many people hit by bombings are killed pretty quickly. Chemical weapons often kill slowly and in am agonizing way.", "Chemical weapons often result in horrifying effects on a large scale and the user has little control of who is effected. And civilians are the most vulnerable to them. Bombs, missiles, and bullets are typically used on specific targets for a military gains. Also, people are OK with killing cars with missiles because we see it all the time. Its normal. That said, when push comes to shove, and you are about to lose an actual war, you use all the weapons you have. The world tried to ban them because you can't use what you don't have.", "Blame WW1 when chemical weapons were just getting started. The generals were well used to conventional weapons like bullets and bayonets. But chemical weapons were a new thing, horrifying, and it showed them just how terrible war is. Next, chemicals poison the land and lie in wait for the weather conditions to change. A shift in wind or sudden rainfall could start killing their own men. Even days later. They cannot be controlled. Next, a well prepared army had little to fear in chemical warfare, civilians did not have those preparations. The generals wanted to feel honorable, and while it's honorable to kill 10000 soldiers in war, it's not honorable to kill 10000 civilians. By the same token, there are bans against cluster munitions and minefields, bans that came about from the precedence of banning chemical weapons."], "text_urls": [[], [], []], "score": [21, 5, 5]}}, {"q_id": "63h02n", "category": "Repost", "title": "Why would you choose a trebuchet over a catapult?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfu1pky", "dfu0sht", "dfu0qcv", "dfu96ps"], "text": ["By \"catapult\", I assume you mean a device where a wooden length is bent back to gather force to hurl a stone. The upper limit of the force you can gather for this device (which thus sets your upper bounds for range and weight of projectile) is a function of the tensile strength of your \"bending arm\". With a fixed maximum force, that means you have a set maximum range. You're also stressing your \"bending arm\" in the ordinary process of use, which means each use carries the risk of partial to catastrophic failure with the arm breaking at some point. The trebuchet gathers force through gravity and a lever-arm. The weigh-bearing basket is the limiting factor on how much gravitational energy can be stored, with the lever-arm determining the final energy released. Thus, it's possible to generate a **lot** more energy, for greater range, heavier projectiles, or both. The trebuchet has its own risk of failure, but it's most likely to fail after the shot is released. It also has a longer \"reload\" time, as it's necessary to unload the basket, reset the arm, and then reload the basket.", "Speaking from personal experience, back when I was in high school, we had to design and build a catapult for physics class. My classmate and I built a trebuchet(which is still technically a catapult). We went for the trebuchet mostly because it was easy to build(just a pole on a pivot with a weight on the end) vs a catapult(which would have required finding a material that would be strong enough and finding a way to mount it). So yeah, I chose a trebuchet because it was easier to build than a catapult.", "A trebuchet is capable of hurling heavier weights a longer distance as it doesn't rely upon the elasticity of materials but rather weight and gravity. However they are often considered to be larger and to be harder to move and quickly reload.", "ELI5: why do people care so much about this question?"], "text_urls": [[], [], [], []], "score": [48, 13, 10, 3]}}, {"q_id": "63hio2", "category": "Repost", "title": "What Determines the Value of Art?", "title_urls": {"url": []}, "selftext": "How can someone paint something like [this]( URL_0 ) and have it sold for millions of dollars when anyone in the world could paint the same thing?", "selftext_urls": {"url": ["https://redflag.org/wp-content/uploads/2012/10/Barnett-2.jpg"]}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfu4w53"], "text": ["Art is subjective therefor it's worth what someone is willing to pay for it. It has no *real value* other than the value someone would place on it. Paintings can go on sale for millions but if it doesn't sell its worth fuck all. If it sells for 30k it's worth that to some people, it may re sell for more or less depending on the artists popularity and rarity etc."], "text_urls": [[]], "score": [6]}}, {"q_id": "63hmf4", "category": "Repost", "title": "Why are electric vehicles more carbon efficient? The electricity comes from power plants, right?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfu5w5w"], "text": ["A car engine turns about 30% of the energy from gas into motion. The other 70% is lost as heat. Power plants that use fossil fuels use the heat from burning fuel to heat water that turn a generator. This is a more efficient conversion of the energy. Add to that, that not all of the electricity is generated by fossil fuel. Some planets are hydroelectric, wind, or solar. So an electric car is also running of some carbon-zero energy sources as well."], "text_urls": [[]], "score": [5]}}, {"q_id": "63kqbi", "category": "Repost", "title": "Why is a human's dead weight heavier than if they were even slightly conscious?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfuwfpx", "dfuuuug"], "text": ["A conscious person will shift the centre of their weight closer to the person carrying them, thereby making them easier to lift. An unconscious persons limbs and head will dangle off to the side increasing the effort required to lift. It's like the difference between carrying a bar bell (simple enough) versus a sofa (too unwieldy). They're not heavier. It's just their centre of mass is uneven forcing you to put more effort to maintaining balance.", "The body will naturally try and move in the easiest way possible, so it will shift its weight and help as much as possible while concious"], "text_urls": [[], []], "score": [8, 3]}}, {"q_id": "63ktg1", "category": "Repost", "title": "Why is internet in Australia crap ?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfuw6c2", "dfuvxde"], "text": ["It's a large continent with a small population, and it's very isolated from the rest of the world. That means you have to lay a ton of undersea cables connecting Australia to Europe, Asia, and the USA, while not having many people to fund it. In addition there has been political back-and-forth on it leading to issues. Basically, one major party argues that high-speed future-proof fiber should be partly publicly funded because it's going to be crucial fundamental infrastructure (like the road and water systems) in the future and Australia doesn't have the population and population density for it to work by market forces. The other party disagrees, sometimes for controversial reasons like considering the internet an entertainment medium or having a much lower definition of acceptable speed. As power shifts between the parties, the level and future of internet infrastructure changes. It is worth noting that Australian internet access is generally improving at a rate better than in the Americas. Australia has traditionally had universal transfer caps, and in the last few years they've started disappearing; the USA and Canada have traditionally not had them, but in the last few years they've started appearing. And for the same price in the same house, I have gone from 1.3 Mbps to 22 Mbps to 94 Mbps over the last 5 years.", "95% of the English language internet is located off the island. This means they need transoceanic cables to connect to the rest of the world. It's a long distance, there's a small population & there not any other major developed countries nearby so there's not a lot of money in laying new cables. Since there's shitty connectivity to the outside world, the whole island is stuck sharing some undersized connections. This is on top of the problems that low population density causes with laying broadband lines on land."], "text_urls": [[], []], "score": [5, 4]}}, {"q_id": "63m51t", "category": "Repost", "title": "If wage gap exists between the sexes, why can't businesses hire more women as a way of saving money on salaries?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfv6x7u", "dfv5tgz", "dfv5tlz", "dfv77c6", "dfv5rzb", "dfv5xtm"], "text": ["> If wage gap exists between the sexes It doesn't. The \"70 cents to the dollar\" stat that people throw around doesn't take into account things like hours worked, years of experience, etc. When you control for these things, the gap closes to 98 cents to the dollar. The slight difference here is believed to be differences in how aggressive men and women are when negotiating salaries and raises.", "They could seek out women, but it is illegal to pay someone more or less based solely on their sex, age, etc. That said, the wage gap doesn't really exist in the way that it is often portrayed. Generally speaking there is little to no wage gap for the same work in the same field/position. The wage gap is simply taking all income of full time earners of men vs women in the country and comparing them. This \"gap\" of all overall earned income between the sexes doesn't take into account actual hours worked, education level, position, fields they elect to go into, etc. Women as a whole tend to work less hours, in jobs that are less stressful/dangerous, have more flexibility with hours and choose to go into fields that are generally less paying than men. This among many other similar factors is what contributes to the vast majority of the wage gap. There's a lot of propaganda and misleading information in the news/media that try to make people believe otherwise, but it goes against all facts and data. It's more of a politically correct argument than a sound/rational one. The truth is that women are more likely to get a degree and in nearly all metropolitan areas of the US single, childless women earn more than men. As these trends continue in favor of women, young men have begun to speak out and advancing the myth of the wage gap is slowly becoming less politically correct as the current generation of workers enter the job market and find that men are actually less \"privileged\" than women in many regards. The \"wage gap\" is largely a product of life choices that women and families make for themselves and not something that can be explained squarely as a product of bias in the workplace.", "The wage gap isn't real. Not in that sense. The only way women make less is if you look at every profession of both sexes and average out incomes. The reason the gap comes up is that men tend to take higher paying jobs like doctors and construction workers. As where women tend to take jobs like nurses and teachers which pay much less. There's exceptions but that's really the only way it works out to a gap.", "It's just a myth to get more Democrats outraged by inequality even when there isn't inequality. That's one of the ways the left tricks young sensitive people to vote for their party.", "First: supply and demand. If the demand for women increases, then that drives up competition and increases salaries. Second: a wage gap exists between entry level employees and C-level employees, so why don't business replace all their C-level employees with entry level employees?", "It is illegal to discriminate in pay between genders. The difference in wages between men and women comes down to differences in the types of jobs men and women take and differences in tenure. Women are paid the same for the same work as men. Women do not tend to have the same sort of education, participate in the same industries, or stay in their positions for the same periods of time as men do on average. What this means for the employers is that even if they look for people to fill particular roles and are completely blind to gender, there will still be differences in the average pay of women vs men."], "text_urls": [[], [], [], [], [], []], "score": [9, 9, 7, 5, 5, 5]}}, {"q_id": "63mwrw", "category": "Repost", "title": "The \"sovereign man\" movement, wherein people act like they not subject to the laws of the land. How does this work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfvfaql", "dfvcx05", "dfvcn1y", "dfvcn6q"], "text": ["Lawyer here. > How does this work? It doesn't. The Sovereign Citizen/Freeman-on-the-Land/Moorish movement is a complete and utter fabrication devoid of any legal substance or intellectual rigor. Not terribly long ago, con artists began giving seminars and selling literature that ultimately formed these movements. Their ideas are based on very tortured and supremely technical interpretations of ancient laws, which, when mixed with a lot of mumbo jumbo and logical witchcraft, result in academic-sounding nonsense. But this nonsense is appealing to some people because it offers them a (supposed) solution to their problems, so they buy into it even though they don't understand it. They _want_ to believe they can trade in their birth certificate for a huge stack of cash. They _want_ to believe they don't have to pay child support because the flag in the courtroom has gold trim. And so they do. They watch the youtube videos and pay for the seminars and buy the literature. They file arcane and bizarre \"legal\" documents with all sorts of colorful text and stamps because it gives them a greater sense of purpose than just hiring a lawyer (to say nothing of the fact that it's far cheaper, and probably at least a little bit more fun). For a while, courts struggled with what to do with these kinds of people. Judges everywhere tend to take it easy on *pro se* parties (individuals without attorneys). Most often, they simply cannot afford a lawyer, and judges don't want to dispose of meritorious cases just because one party is broke. So early on, the judicial response was slow and tempered. But as the movement grew, so did the burden on the judicial system. Judges get pretty tired of defendants who won't identify themselves in court, who refuse to enter pleas, who interrupt the proceedings to spout nonsense, who make their clerks process nonsensical documents, etc. Now there's something of a playbook forming to dispose of these types of claims. There's a Canadian case called _Meads v. Meads_ (google it), where the judge is faced with a litigant like this. He goes the extra mile in researching the Sov Citizen movemen, dissecting their \"legal\" arguments, and discussing why they don't hold water. I think the movement has produced some newer flavors of insanity since _Meads,_ but it's still a pretty comprehensive overview.", "It doesn't work. People get so wrapped up in their own philosophical interpretation of the law that they forget that law is ultimately about who has the power to enforce their views.", "It doesn't work. They make dramatic leaps of logic to create a poorly conceived view of \"how law works\" and then lose in court.", "It \"works\" in that someone believes crazy people with stupid ideas about how the law works and then simply declare that the law doesn't apply to them. Law enforcement however disagrees and applies the law to them regardless of their views on the subject, and people generally point and laugh at their idiocy."], "text_urls": [[], [], [], []], "score": [22, 6, 4, 3]}}, {"q_id": "63pd76", "category": "Repost", "title": "If human body temperature is 37 C (99 F), why is it when it's the same temperature out we feel incredible discomfort?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfvxtgc"], "text": ["We generate heat, and then lose it. When it's closer to 70 degrees, its a good balances of generating heat and then cooling down. When its 99 degrees out, we are generating heat, and then still heating. Basically, when it's cooler out our body can generate enough heat to keep us comfortable. When it's hot out, the heat we create is just in addition to it being already hot. Thats the general idea."], "text_urls": [[]], "score": [4]}}, {"q_id": "63q08n", "category": "Repost", "title": "Why aren't taxes just done automatically?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfw3iac", "dfw4dfc", "dfw3mw7"], "text": ["Planet Money on NPR had an episode about this a little while ago. A big reason is that tax preparing (H & R Block, TurboTax, etc) is a huge industry that employs a lot of people, and they've been able to leverage that into political power to keep taxes complicated.", "We have a pay as you earn system in the U.K. It's your employers job to get your tax right so all a person needs to do is double check that they're in the right tax code when they start work. We get sent a document each year called a P60 which is a statement of tax paid. [PAYE]( URL_0 )", "It could be possible for the IRS to provide a pre-filled form using the information they have, but that may be discouraged by the tax preparation companies. And for the majority of filers, they have numerous free options for filing out federal returns, although they require manual entry of many forms. However, for some people, there is a lot of paperwork involved. (I'm 21 and my return was over 12 pages long, and I could not use the 1040A or 1040ez forms). For those living without complicated situations, the IRS has a one-page simplified 1040ez that can be filled out in minutes."], "text_urls": [[], ["https://en.m.wikipedia.org/wiki/Pay-as-you-earn_tax"], []], "score": [11, 7, 3]}}, {"q_id": "63qqd0", "category": "Repost", "title": "Why if you throw, for example, a spider from a tall height, chances are it will survive with no injuries, but if a human is thrown from the equivalent height, we'd be badly injured/die?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfw9wvr"], "text": ["Spiders aren't heavy enough for them to be greatly damaged by a fall, plus their skeletons are outside, so it acts like armor. Humans are heavy, and our skeleton is inside, for support rather than protection (skull, spine, and ribs notwithstanding)."], "text_urls": [[]], "score": [3]}}, {"q_id": "63u4la", "category": "Repost", "title": "What is offensive about the Kendall Jenner Pepsi Commercial?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfwz8at", "dfwzenf", "dfx16fd", "dfx1rgt"], "text": ["Reducing the complex and nuanced issue of police tensions with protesters to an oversimplified use of the platitude \"cant we all just get along, man?\". Shitty sugary sodas won't solve widespread issues.", "\"Police are systematically targeting, killing, or imprisoning in a forced labor system the black youth of America. We demand justice!\" \"Have a soda, you will feel better.\" \"Oh, well it's all good, man.\" That doesn't seem maybe a little offensive?", "Besides what other comments have said, it's opportunistic as fuck. Capitalizing on what is a huge social issue like this is in poor taste. Expect Pepsi to make some huge donation or start a foundation very soon.", "Pepsi claims to care about social justice but in reality it is just trying to sell drinks. The ad is superficial and disingenuous, and quite obviously so. The use of a Kardashian family member does not add credibility."], "text_urls": [[], [], [], []], "score": [60, 35, 27, 13]}}, {"q_id": "63v8ij", "category": "Repost", "title": "How exactly does radiation kill you? Slowly and instantly?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfx8v4w", "dfx8yi7"], "text": ["Radiation kills off cells. The type of radiation and the exposure dose determines how death occurs. Extremely high doses can be instantly fatal while lethal high doses can do things like kill off the cells of your GI tract and prevent the body from taking up nutrients. Other forms can cause cancers or other diseases that have various lengths of time before being fatal. Mostly, its unpleasant.", "It depends on the degree of exposure. It can damage the structure of cells, and also DNA. If the structure of a cell is damaged, it can kill cells outright. If the DNA is damaged, it can be in such a way that the cell divides problematically and does not 'terminate' as desired, resulting in cancer. How you die depends on what is damaged, to what degree that is damaged, and what form the damage takes. If your GI tract is ruined, versus if you get cancer in your GI tract, as an example. A low dose exposure may not cause you any noticeable harm at all, and in fact we are all exposed to some level of background radiation all the time."], "text_urls": [[], []], "score": [7, 3]}}, {"q_id": "63wbl5", "category": "Repost", "title": "How to anti-virus scanners scan for a virus? How do they tell what is and isn't a virus?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfxigx7"], "text": ["Most modern antivirus programs scan for virus in a variety of ways simultaneously. Most will use some combination of known virus \"names\" (common file names and extensions that have already been identified) and a heuristic analysis that recognizes specific \"behaviors\" that are considered harmful. For instance, let's imagine that you're a business, and you have a database located on your server. If a program were regularly turning itself on, accessing the data in the database, packaging it, and sending it out through the internet to some place, a heuristic analysis may read that behavior as potentially malicious, and quarantine the program. That doesn't mean the program is a virus, or is doing anything nefarious or harmful in any way -- it's just that a lot of viruses behave that way, and the heuristic analysis is just looking for a set of behaviors. I actually work for a company that makes a kind of data integration software that does just that -- accesses data in a database to be made available to different partners for different services. We often have to work with our clients to set up exceptions so that our files don't get quarantined (or in some cases, outright deleted) by their security software."], "text_urls": [[]], "score": [3]}}, {"q_id": "63xpmr", "category": "Repost", "title": "What exactly happens when we die of \"natural causes\" or old age?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfxthc6"], "text": ["As we get older (on the span of hours), our cells die. To replace them, our body splits living cells into more cells (mitosis). Sometimes, the two copies of the cell aren't perfect. Generally, cells work correctly and everything is good, even if there are some mistakes in copying DNA for the cell split. As we get really old (on the span of decades), these mistakes add up, and eventually, our cells are not able to split quickly and correctly enough to counteract natural cell death."], "text_urls": [[]], "score": [3]}}, {"q_id": "63zpq2", "category": "Repost", "title": "How do streaming websites like Netflix etc. protect their videos from downloading?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfyb201", "dfy88ha", "dfyf39o", "dfyicf0", "dfysujy", "dfyq5cl", "dfyhlmj", "dfyz2iz"], "text": ["The monthly subscription price is cheaper than buying the hard drives necessary to save the shows you might download. People don't want to pirate content, its just that when someone wants to charge an unfair price for it, or tie it down with all sorts of BS use restrictions, people will. Netflix proves that if you ask people to pay a reasonable sum for content and provide it in a nice, easy, manner, you don't have to worry about piracy. Edit: Seeing some of the reply comments I really think you can't read my comment without also reading /u/tomatoaway 's comment (and I would like to think vice versa as well).", "Rather than sending the whole video as one continuous UDP procession, you can instead split it into HTTP packets and send it. These packets can then contain cookie-specific information that only correctly parse data for the current web client, so copying and pasting the video address into another browser won't work because it lacks the same cookies (or that cookie is already in use). Most browsers worth their salt let you jump around this though, by holding a record of all packets that were recieved and letting you save them externally. Edit: I should also add, [don't use Netflix/Chrome if you value an open internet]( URL_0 )", "It's not a simple video file that you would download from a torrent or through P2P. It's an adaptive stream using what's probably a proprietary format. Meaning, if your connection slows down, the quality will adapt and look blurry. If your connection is fast, the quality will get better. Most offline video players support something called variable bitrate (VBR) but it's not quite the same thing. That isn't really the issue though because if people wanted to get around that and save the videos they could. But the point is that it's not worth the effort when the subscription is so cheap and they can watch the shows immediately when they're released. With that said, people *do* download Netflix shows from torrents so it does happen. Also, I believe Netflix started allowing offline viewing not too long ago so that probably makes it easier. Another important point that makes it more difficult is that Netflix doesn't download the whole movie. If you pause the stream, it will only buffer so much ahead of where you are. This also allows it to pick up where you left off if your computer crashes. So there is a constant communication between your browser and Netflix that makes downloading videos a bit more tricky than they otherwise would be.", "There are always ways around it. It is difficult to download it as a file, but you can get a program to record the screen while it is playing and save that recording. I remember when I was big into downloading and got some music, but it was DRM protected so I could not copy it to another device or burn it to a disc. So I got a program that plays and records a new file and that was a good way around that.", "While I don't know about the Netflix specifics, I worked in a similar system 6-7 years ago for a music streaming service. I was responsible for this area. While I can't go into details, up to now, we still haven't found anyone that 'cracked' the system. The only way to 'download' the music from that system is by recording the audio output in realtime. I developed a real-time encryption server that encrypted the music as it was being sent, and was based on several variables and independent of each user. We also had the audio data encrypted in a different format in memory and only decrypt it in small blocks (again based on several variables) when sending it to the audio device. I was approached by both Spotify and Netflix due to this project but ended up refusing as I knew part of what they wanted was the algorithms I developed and they were at the time property of the company that employed me.", "They don't really, its trivial to capture the stream and save it to disk. But, you don't really gain anything from doing this, as you can watch whatever you want, whenever, so all you do is fill your harkdisk with files you don't need. If you wanted to, you could pirate them from other sources anyway, so they just make it slightly trickier than doing that. No point making it any more secure.", "They don't not really well they do take some steps but it's annoying to pirates than anything else. Worse case scenario is people would just record the video right off their screens if need be to pirate the video. You don't even need to go that far though because there are ways to grab that data straight from a web browser. Thing is that Netflix is convenient and cheap enough that most people don't bother with that usually and the ones that do wouldn't have paid for the service anyway. They even actually added the ability recently to download stuff for viewing offline to even further the convenience aspect.", "Pirate here. Been doing it for almost 10 years from sites like PirateBay, Demonoid, Kickass and even Mininova (back when it was good). Netflix really can't protect their stuff from being downloaded fully. They can protect it from things like Extensions on Google Chrome (like video downloader professional) but if someone has recording software, like Bandicam, and uploads it on a website? then it can be downloaded of course but the quality isn't that great. However most people don't download Netflix original content (house of Cards, Daredevil..) because the membership fee is so cheap, maybe something like The Walking Dead because it doesn't hit Netflix til later in the year after it finishes off the season on AMC. Personally I don't see a point in pirating Netflix original shows because of how cheap it is and there are even shows and documentaries that are old enough that you'd be hard pressed to find on any pirating website. The only people who do are those who're tight for cash or live in countries where Netflix isn't available or the show itself is not available on Netflix in their region."], "text_urls": [[], ["https://stallman.org/netflix.html"], [], [], [], [], [], []], "score": [210, 107, 16, 5, 5, 4, 3, 3]}}, {"q_id": "6416z5", "category": "Repost", "title": "For websites, what's the difference between .com, .org, and .net?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfyjxaw"], "text": ["The idea was that .com would be used by general-purpose commercial entities, .org would be used by non-profits, and .net would be used by network providers. There's no policing or enforcement of this. Anyone can register a .com, .org or .net and they behave identically."], "text_urls": [[]], "score": [4]}}, {"q_id": "64186p", "category": "Repost", "title": "Why do some products say \"refrigerate after opening\" when they can sit on a shelf at a grocery store at room temperature?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfyk9u8"], "text": ["Those foods are usually vacuum sealed, and are therefore protected from contaminants. Combined with the preservatives inside them, they can sit on a shelf for months or years and still be edible. Even most foods that have a \"best by\" date, are still perfect edible months or even years after they have \"expired.\" But once you open a product like that, you increase the risk of contamination which may cause the food to spoil. Keeping it refrigerated slows or prevents the growth of bacteria that may put the food off."], "text_urls": [[]], "score": [3]}}, {"q_id": "642rug", "category": "Repost", "title": "Why do most females \"throw like girls\"?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfyy21i", "dfyygo9", "dfyy9bx", "dfyztmr"], "text": ["It's just from lack of proper instruction. At least in the US, people (boys and girls) who don't play baseball or softball aren't taught proper throwing mechanics, and the \"elbow in front of the hand\" technique is just what your brain thinks needs to happen. Try to throw with your non-dominant hand and see if you \"throw like a girl\" I bet dollars to donuts you will.", "People in this thread have mentioned that girls who \"throw like girls\" don't have athletic training, which is definitely true and almost certainly the primary factor. However, it would be unfair not to mention that women are physically weaker than men. Studies have suggested that nearly all women are weaker than nearly all men. [Graph.]( URL_0 ) I mention this only because OP asked if there was a physical difference. There is, it's just not the biggest factor.", "\"Throwing like a girl\" is really not knowing how to throw properly, lack of practice, and a lack of muscle memory. Your left arm is evidence of that. The phrase most likely came about because boys have historically been more interested in playing sports while girls were often actively discouraged from playing, leading to the belief that an inexperienced arm is a \"girls arm,\" so to speak. There is no structural difference between a girl's and boy's arm that would make someone throw a ball differently.", "Blah blah triggered etc anyway this is actually interesting my sister and I were both pitchers in a softball league, it took her a lot longer to get the hang of it underhanded but once she did she was more accurate then me although my pitches were way faster. When we threw overhand no matter how many times they tried to beat It into her head she always \"threw like a girl\". All the guys got it immediately they threw like a hardball pitcher while all the girls did this weird throw using a shit ton of elbow and the arm would only extend at the last minute causing an extremely weak throw overhand. Personally I think it has to do with how the brain works. Only 1 girl got the hang of it at a decent rate out of the 10 that were on the team. After a few years that weird throw was eventually ironed out of their brains but they all did that weird elbow throw for ages. Science dictates that most girls tend to be better right hemisphere and men better left hemisphere so I would say that has something to do with it. Dudes tend to be really good at replicating actions and things while women seem better at coming up with original ideas and planning for most scenarios. At the Olympic stage women are 10% weaker than men which is negligible. This gap become a lot wider in normal everyday life as women tend to be smaller then males. When you take all the feminism and bullshit out of it and look at the data it can be really revealing."], "text_urls": [[], ["http://www.unz.com/wp-content/uploads/2016/07/Pa3fEwuyuzaNqxWWfjkfuQecyVO6IZcSiNsl7n5uEg8.png"], [], []], "score": [5, 4, 3, 3]}}, {"q_id": "6430kq", "category": "Repost", "title": "What makes your body decide you're allergic to certain things?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dfz05nc"], "text": ["An allergy is the incorrect identification by your body of a chemical as being toxic. Some people are allergic to foods such as nuts because their bodies identify chemicals in those foods as being toxic, while bodies of people who are not allergic do not identify those things as being toxic. It comes down to the receptors on the surfaces of the cells that detect toxins."], "text_urls": [[]], "score": [3]}}, {"q_id": "649yxb", "category": "Repost", "title": "Why does no other animal have their own language like humans?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dg0hwg7"], "text": ["Some do, mostly whales and dolphins are thought to have some of the most complex languages other than humans. Bottlenosed Dolphins for example, have been shown to have \"name clicks,\" sounds other dolphins use to get their attention. Human researchers have reproduced these sounds and can still get the same dolphins attention."], "text_urls": [[]], "score": [3]}}, {"q_id": "64ath9", "category": "Repost", "title": "Why are cartoon characters always drawn with 4 fingers rather than 5?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dg0p607", "dg0zads"], "text": ["according to this: URL_0 because it was cheaper (quicker) this way. (also that's why there are exceptions to this rule, like God in the Simpsons, main characters in Disney movies, etc)", "In the sense of practicality, it's cheaper and much easier to draw. It's basically a work around that made animation much easier to produce. Obviously the hand of a character plays a vital role when trying to depict an action or emotion, so it is crucial to animate the hand more effectively without the burden of adding a finger. However, some shows are starting to include the fifth finger. One example is Steven Universe. Consider a YouTube search of why early Disney Characters wore white gloves. It could tie its way into answering your question."], "text_urls": [["http://www.refinery29.com/2017/03/147781/why-cartoon-characters-have-four-fingers"], []], "score": [28, 8]}}, {"q_id": "64b0ev", "category": "Repost", "title": "Why do we get heartaches when feeling sad", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dg10559", "dg0zyg7", "dg10ooz"], "text": ["I recall it has something to do with stress and blood flowing rapidly from your heart to throughout your body leading to that \"heart broken\" feeling.", "You got heartbroken by an ex too? :(", "Increased levels of cortisol I'd imagine. Also, when you are emotionally distraught, you breathe less uniformly. Leading to a build up of lactic acid resulting from anaerobic respiration; which can equate to feeling physically exhausted."], "text_urls": [[], [], []], "score": [11, 6, 4]}}, {"q_id": "64bcom", "category": "Repost", "title": "Why are chemical weapons seemingly more abhorred than conventional weapons? (Chemical weapons are \"banned\" from warfare etc.)", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dg0tvdm", "dg0ty5h", "dg0ts1p"], "text": ["It is has long lasting effects, it kills indiscriminately, and can get out of control very quickly.", "World War 1. They were used extensively by both sides, didn't prove to have much strategic value to winning a battle, because you can't go in the area you just dropped mustard gas on either, and they cause a slow, particularly brutal death compared to conventional weapons.", "It's usually a pretty particularly fucking brutal and vicious way to kill someone, and it isn't as quick and 'humane' as a bullet. War is fucked up, but we need certain rules to prevent atrocities like the Rwandan Genocide (the first case of rape being officially declared a weapon of war)."], "text_urls": [[], [], []], "score": [3, 3, 3]}}, {"q_id": "64cbel", "category": "Repost", "title": "Why is the right hand the dominant hand for most people?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dg1cdv8"], "text": ["I'd like insight. I'm decent with daily tasks with my left hand and was an excellent pitcher in baseball. If I was lefty I definitely would have made the majors if the same shoulder injury didn't happen to the other. (osteoarthritus at 16) now I have a little boy who I try teaching everything lefty. Thinking it was taught not genetics. He always ends up using his right hand by the end of it."], "text_urls": [[]], "score": [3]}}, {"q_id": "64ieb4", "category": "Repost", "title": "Why do we get dark patches under our eyes when we haven't slept enough?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dg2k0s2"], "text": ["Increased cortisol from sleep deprivation causes dilation of blood vessels, which causes the bags under the eyes."], "text_urls": [[]], "score": [139]}}, {"q_id": "64ipxr", "category": "Repost", "title": "What's the difference between unleaded, plus unleaded, and premium unleaded gasoline?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dg2fhvk"], "text": ["The Octane rating is different for each one. Unleaded starts at 87 unleaded + is usually 89 and super is usually 91 or 93 depending on where you live. The octane rating is the fuel's resistance to combustion. The higher the rating the hotter the fuel has to be in order to light off. High performance engines operate at higher temperatures and pressures so they need a fuel that won't light off before the engine is ready. When this happens it can cause severe damage to your engine, but if your engine doesn't need it you're just wasting money."], "text_urls": [[]], "score": [8]}}, {"q_id": "64iry7", "category": "Repost", "title": "What is laughing and why do we do it?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dg2lp77", "dg2nk5v", "dg2vxf4"], "text": ["Laughter is an instinctual jocular reaction to the inevitable ironies relevant to survival; sex, food, water, sleep, relationships to others, excretion, dangers from the elements, death, etc. Hypotheses as to it's evolutionary origin run the gamut. I favor the ones that claim positive responses to inevitable unpleasantness are adaptive for us, as negative responses to them would cause dysfunction through avoidance, thereby magnifying the problems.", "Below is an explanation I recall. Laughing has a similar effect to panting, it helps increase our energy levels to perform a task. Panting out loud also lets others around us know that we've found something good like a fruit tree and that it's safe to approach it without risk. Over the course of many years it helped us to find energy, i.e. be happy about things that usually would bore us to death. This eventually lead to the creation of jokes which help us artificially find happiness in otherwise boring or sad tasks which we were under obligation to complete.", "Laughter, at it's core, is a natural reaction to avoiding death/danger that evolved in order to alert others in the tribe that you are alive and the area is safe. This is the reason we find slapstick humor so funny. Simple things like a pie-to-the-face, or slipping on a banana are funny even to chimps, because they also share a similar evolutionary trait."], "text_urls": [[], [], []], "score": [40, 10, 4]}}, {"q_id": "64itcy", "category": "Repost", "title": "Why do we twitch in our sleep?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dg2gt8v"], "text": ["Basically your brain has a reflex to check if all the parts of your body is still alive. During your sleep, it happens that your brain, as it notices your catatonic state, feels the need to check if some parts of your body are still alive. It does so by sending impulses to the muscles through the nerves in order to obtain a response. The impulse to the muscle is the twitch you have. So don't worry: it's just your brain doing his job at making sure you're fine"], "text_urls": [[]], "score": [23]}}, {"q_id": "64j0qu", "category": "Repost", "title": "How computers store information, even when they're off", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dg2hzv0"], "text": ["There are two types of memory, firstly volatile such as RAM which is consumed while the machine is on and needs power to keep it running. Second is non-volatile and will not be lost on powering off, such as hard drives and SSD memory. Hard drives store the states in charge, i.e. Positive or negative charge for 1 or 0. SSD's have essentially tiny switches which can be set to these positions. Because electricity is then not needed to maintain this information you can safely power off keeping everything in position."], "text_urls": [[]], "score": [3]}}, {"q_id": "64jbt5", "category": "Repost", "title": "Where do electric eels get their electricity?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dg2rlus"], "text": ["Ions. It works just like the way electrical signals travel down your nerve cells, but in the electric organ of the eel, the cells are setup more like a battery than the \"communications wires\" of the nervous system. Just like with nerves there are ion pumps on the cells of the electric organ that maintain an unbalanced chemical and electrical gradient across the membranes of the cells, with more positive ions outside the cells than inside. This means there is a voltage across the membranes. When the signal to discharge arrives at the organ, ion channels open allowing certain ions to flow in, and certain ions to flow out, generating an electrical field as the current flows."], "text_urls": [[]], "score": [18]}}, {"q_id": "64ji6s", "category": "Repost", "title": "Why do words start looking weird if you stare at them long enough?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dg2lryu", "dg2zwd1"], "text": ["It's called [semantic satiation](Semantic satiation - Wikipedia URL_0 ). According to Wikipedia: > The explanation for the phenomenon is that, in the cortex, verbal repetition repeatedly arouses a specific neural pattern that corresponds to the meaning of the word. Rapid repetition makes both the peripheralsensorimotor activity and central neural activation fire repeatedly. This is known to cause reactive inhibition, hence a reduction in the intensity of the activity with each repetition. Jakobovits James (1962) calls this conclusion the beginning of \"experimental neurosemantics\". So tl;dr, based on my admittedly basic understanding: after reading a word over and over, your brain goes \"we're seeing that same signal too much, better tone it down\" and makes itself less sensitive to that word, which is why the word starts to sound less meaningful", "This is really good question, and so awesome that it has an actual answer. I swear this happens to me more often than it probably should."], "text_urls": [["https://en.m.wikipedia.org/wiki/Semantic_satiation"], []], "score": [53, 5]}}, {"q_id": "64jto6", "category": "Repost", "title": "How will a self-driving car react when facing a choice: killing the driver or a pedestrian?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dg2nfcc"], "text": ["There wouldn't be that kind of decision baked into it, deciding which lives to kill. It would follow the standard programming for collision avoidance. If it detected something heading toward it, it would brake, or steer into an available space to avoid the collision, or both. Nothing is perfect. Humans do this already. If a ball bounces into the road, you stop or swerve. Hopefully paying attention as you're supposed to at the lanes and traffic around you so you always have somewhere to go in such a situation. An automated car would do the same thing. The default solution would be to hit nothing. It doesn't matter if its a person or a vehicle. If the sensors detect a probable collision it would slow or move to prevent it. A person is just another thing not to hit. You would have code that also makes sure there is an out in a situation, such as making sure cars are spaced appropriately enough that there's an escape lane, proper distance between vehicles, and everything else. Are things perfect? No, but people aren't perfect either. Accidents happen, usually because of someone doing something stupid, like running into a street."], "text_urls": [[]], "score": [4]}}, {"q_id": "64ke6y", "category": "Repost", "title": "Why do we forget whole chunks of time when we are \"blackout drunk?\"", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dg2v7rg"], "text": ["There's a part of your brain called the hippocampus that is believed to be important to the process of saving your thoughts and sensory experiences into long term memory. Excessive alcohol consumption appears to interfere with two neurotransmitters (gamma-Aminobutyric acid (GABA) and N-methyl-D-aspartate (NMDA)) that are used to communicate between neurons in the hippocampus, and so the theory is that the alcohol stops the chemical process of creating memories until your blood alcohol level decreases."], "text_urls": [[]], "score": [5]}}, {"q_id": "64kfpn", "category": "Repost", "title": "How do airlines often overbook flights?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dg2svyj", "dg2snpd", "dg2st7z", "dg37xvg", "dg2ss45", "dg2zrtk", "dg2tnal", "dg2yyhd", "dg3apac", "dg2zcz7"], "text": ["Because they intentionally overbook them. They know that some people don't show for flights. They have pretty good stats on how many people, on average, won't show, so they know how many to overbook each flight. An empty seat is lost money. Sometimes there are fewer no-shows, and that's an overbook. They do have to compensate people for bumping them from the flight, but that's cheaper than having unsold seats.", "It's intentional. If someone doesn't show for a flight or cancels, that's money the airline doesn't make on that flight. Overbooking gives them some cushion for cancellations and allows them to make more money per flight.", "Large planes use almost the same amount of fuel whether they're half empty or packed, and airline companies know this. They also know from experience that some small percentage of booked passengers don't show up. They maximize profit margins (the margins on cheap seats are razor thin) by booking 102 seats on a 100 seat plane and assuming that at least two aren't gonna show. Usually they're right, but occasionally all 102 people show up and someone's waiting for the next plane.", "As a crew scheduler, If a pilot or flight attendant gets sick somewhere we don't have reserve staffing I have to overbook flights to get a back-up out there. It's better to strand 1 person in Chicago than 97 in Fargo. Plus if the plane doesn't leave Fargo then planes that the crew in Fargo were supposed to operate later in the day might also get stranded. It can easily snowball into a huge mess, better to ruin one person's weekend than completely screw over 97 (or more) others. Edit: ok back from work let's see what Reddit thinks Edit numero dos: Reddit had 3 misunderstanding and 2 jokes about beating up an old Dr. I think I righted the misunderstandings and doubled the joke total.", "they know that some people will not show up for the flight, so it is prudent to overbook to make sure they fill the flight, and if their statistics betray them, they will bump them to a later flight for a few hundred bucks. cheaper to pay to bump people on occassion than to fly with 10 empty seats almost every time.", "Here's an outstanding video which should cover your question. [I hope this helps!]( URL_0 )", "Overbooking flights in pretty common because airlines know a certain percentage of people will miss their flight or change their plans. Depending on the particular route it might be more or fewer seats. A Tues 8am flight from Chicago to New York probably has a lot of changes since it's mostly business travel, so it might get oversold by more seats that other flights... say a Sat AM flight to Orlando, which is much less likely to have changes since a family planning a trip to Disney World is going to keep their plans for Disney World.", "Further how is this not false advertising when they sell more seats than they have ?", "Airlines want to make as much money as they can, which means operating each flight as close to 100% full as possible. Imagine you're operating an airline. Most of the time, a few people don't show up for their flight. So you start selling a few extra tickets for each flight. If everyone shows up, you don't have seats for them all. But everyone showing up is very unlikely. Actual airlines use statistics to determine how many no-shows are likely to happen on each flight. They factor in everything, such as where the flight is to and from, age of the passenger, gender of the passenger, if they're flying with anyone else, the time of the flight, the weather that day, and a *ton* of other factors. With all of this information, they can get a *very* good estimate of how many people won't show up for a particular flight. So they then go ahead and sell more tickets for that flight, based on their estimate. Most of the time, there's no issue. Everyone who shows up gets to fly. But some of the time, there is an issue, because more people than expected showed up for the flight. In these cases, airlines typically offer incentives for travelers to voluntarily give up their seat on the flight, and although this costs the airline some money, the extra money they make by overbooking to get every flight as full as possible more than offsets this cost.", "When I travel for my company my secretary will book multiple flights in case I want to leave earlier or later. We only get charged for the flight I take."], "text_urls": [[], [], [], [], [], ["https://www.youtube.com/watch?v=ZFNstNKgEDI"], [], [], [], []], "score": [386, 81, 56, 18, 14, 9, 5, 4, 4, 3]}}, {"q_id": "64ksls", "category": "Repost", "title": "Why do many guys find legs, foot, stockings, pantyhose, etc. sexy? Aren't those parts far away from sexually sensitive zones, and not part of the female secondary sex characteristics?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dg2xsit"], "text": ["Actually in the primary motor and primary somatosensory cortexes, the area of the brain associated with the genital areas is very close to that part of the brain associated with the legs and feet. The brain overlap theory states these areas can communicate with each other leading some individuals to sexualise feet. URL_0"], "text_urls": [["https://s-media-cache-ak0.pinimg.com/originals/d1/92/9b/d1929b83315290322cf8e1ed06ba0830.jpg"]], "score": [3]}}, {"q_id": "64lnqg", "category": "Repost", "title": "At what \"fps\" do a human's eyes see at?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dg34v7o"], "text": ["Eyes don't have a FPS. Your eyes take in a constant analog stream of light (until you get down to the individual photon level). The speed at which you see is mostly limited by the speed it takes the nerves in your retina to process and send the information to the brain. At that point, your brain processes the signals coming in to make your consciousness \"see\" whatever you are seeing. This is a combination of what the retinas are actually seeing, and what your brain \"fills in\" as what it thinks you should see. This is where a lot of optical illusions happen. If what you are asking is at what FPS do we need to see something for it to appear real, that's different. Things may appear real at 24 fps (the traditional cinema fps, which was mostly chosen because it was the slowest that would be flicker free), but that's because your brain is good at filling in those details. Watching the same video at 60 or 24 fps should be pretty noticeable. Some people think the slower traditional cinema speeds are better because of the motion blur that naturally occurs at the slower filming speed. 60 fps is too crisp and clean in motion scenes, not reproducing accurately the motion blur that naturally occurs to us (incidentally, this gets added in during post production in higher fps films now). But it's also an argument that we are seeing more frames than people previously thought. How many frames can your sight really differentiate? There's no solid answer for that. And it may vary wildly between individuals. Many people claim to be able to see a drastic difference between a 144Hz monitor and a 60Hz one. Others may not. But this also depends on the application. For instance, gamers often want the absolute highest refresh rate because they don't want to miss a single frame of action, in case that frame happens to have the critical info they need. But they often have been training themselves for years (not deliberately, necessarily) to be able to pull the data out of those frames quickly. The brain is pretty fluid in its abilities, so having it change how it processes visual stimulation is not surprising at all."], "text_urls": [[]], "score": [25]}}, {"q_id": "64lqtl", "category": "Repost", "title": "With the universe constantly expanding in all directions, is there a centre of the universe and how do we find it?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dg34f1l", "dg3em7h", "dg38g7d", "dg3j2al", "dg3akbb", "dg3ec4j", "dg3r80b"], "text": ["No, the general thought is that there is no center. Everything is moving away from everything else and there is no central point.", "The center is right where you are standing. If you hopped in a time machine that was stationary but could travel through time like the one in H.G. Wells's \"The Time Machine,\" and set the dials for the beginning of the universe, you'd zoom back through time as the universe shrank around you. The universe would shrink to a size too small for you and your time machine to be in before you got to the beginning though, and even before you got to the end of the [cosmic inflation]( URL_1 ) period, at which time the universe was about the size of a grain of sand. On the other hand, we can \"see\" all the way to the cosmological horizon already, the edge of the observable universe. What we see there is photons that were emitted about 380,000 years after the start of the universe. Before that, the universe was so densely packed with stuff that any photon emitted by one atom would be absorbed by another atom almost immediately. Those photons have been travelling for so long and so far that they are all [redshifted]( URL_0 ) to microwaves, but in any direction, that redshift indicates a distance of 46.5 billion light years. The observable universe is a sphere 93 billion light years across, with you at the center.", "It's all the centre. Like the surface of a balloon when you blow it up, but with the extra dimension.", "Since everything is moving away from everything else, it will appear as though the point of observation is the center of the universe. That makes you the center of your universe. Have a nice day!", "The more space between two object the faster the expansion is. This is due to dark energy. This means that where ever you are in the universe everything is generally moving away from you (with exceptions due to gravity). This means that all points appear to be the location of the big bag and the center of the universe from that locations frame of reference. Therefore it is not possible to find the center ( if there is one ) with this method. An easy way to demostrate this is to take a rubber band cut it so that it is a straight line and make different points on it with a marker. Stretch it and check the movements of each of the points relative to several different frames of reference and you will find all things seem to move away from the frame of reference you choose.", "This [video by Minute Physics]( URL_0 ) explains it rather well.", "Has any of this ever been animated? It might be a lot easier to understand if there was a visual to illustrate the concept. I don't know, it may be so complicated that a visual model is impossible."], "text_urls": [[], ["https://en.wikipedia.org/wiki/Redshift", "https://en.wikipedia.org/wiki/Inflation_\\(cosmology\\)"], [], [], [], ["https://www.youtube.com/watch?v=W4c-gX9MT1Q"], []], "score": [170, 11, 10, 9, 9, 4, 3]}}, {"q_id": "64n99i", "category": "Repost", "title": "Why are controversial moments in sport or politics dubbed \"gate\", e.g \"towelgate\" or \"deflategate\"", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dg3ho3x"], "text": ["Um, because of watergate? EDIT: Oh right, most of reddit was born long after Watergate, forgot :) Well this happened, it was a thing: URL_0"], "text_urls": [["https://en.wikipedia.org/wiki/Watergate_scandal"]], "score": [3]}}, {"q_id": "64q6u8", "category": "Repost", "title": "How does a bank work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dg45agn"], "text": ["A traditional bank offers two services: Loans and savings. Loans are where the bank will lend money to a person or business, who will then pay the money back to the bank (plus interest). Savings are where a person or business will ask a bank to hold onto their money for them and the bank will pay them interest over time. The money that banks use for loans is the money deposited by people saving with bank. Banks make money by charging a higher interest rate on loans than they pay out to savers. For example, a bank might ask for 6% interest on a \u00a3100 loan and then pay 1% interest on a savings account with \u00a3100. This means that the bank will make \u00a35 in profit. Investment banking is quite different. An investment bank offers advisory services to businesses looking to \"float\" themselves on the stock market. The investment bank can also buy all of a company's shares when they are issued and sell them to investors on the company's behalf (saving the company a lot of time and effort with finding investors). The investment bank makes money by selling the shares for a higher amount than they paid for them. As investment banking is based on a lot of speculation (trying to predict changes in the market), it's inherently risky. If an investment bank buys 10,000 shares in a company at \u00a320 each, it could sell them for \u00a325 (25% profit) each if it correctly predicts the market but it could also get it wrong and have the shares be worth less on the market than what they paid for them."], "text_urls": [[]], "score": [4]}}, {"q_id": "64qo7r", "category": "Repost", "title": "is the universe as long as it as tall, or does it expand farther in one direction than the other", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dg48c3y"], "text": ["The universe is likely infinite in size. The observable universe, the part we can see, is limited by the speed of light and age of the universe so it is a sphere."], "text_urls": [[]], "score": [5]}}, {"q_id": "64qwn8", "category": "Repost", "title": "What is a raspberry pi and why is it so significant?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dg4ac9u"], "text": ["They are very small, very cheap computers. They have very little processing power compared to more expensive devices, but they are powerful enough to run a basic desktop OS. You can use them for all sorts of things such as emulating old video games, or as a media player, a home automation controller. They also have generic IO connections so they can be used to control things like motors, allowing you to use them for basic robotics for example. They're aimed at hobbyists mainly. It's up to you to configure/program it to do whatever you want."], "text_urls": [[]], "score": [10]}}, {"q_id": "64s82v", "category": "Repost", "title": "How did programming start?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dg4njsa"], "text": ["In a couple of ways, depending on how you look at it. The first \"programmable machines\" in the modern sense were looms and player pianos. Instructions would be encoded and punched into paper tape or cards, and the loom would weave patterns/piano would play music based on whether a lever/cog/puff of air made it through a hole or not. The first electronic computers were single-purposes devices. To change their programming you very literally rewired them. These early computers would have \"wiring boards\" that consisted of pegs and wrapped wires, and you'd wrap different pegs together to change the program. With the advent of stored-program computers, things got a little easier. The earliest ones would have a bank of switches as wide as a memory word, and a button that said \"store\". You'd flip the switches to represent a word of memory (on switches were 1 bits, off switches were 0), hit \"store\" and that word would be stored into memory. Believe it or not, they actually made these awesome giant-roller things with pins on them like music boxes that they'd roll up to the computer and hand crank - the pins would flip switches on and off and it made life easier. Early computers also used punched cards, which got their start as I said above with looms (and theorized by Charles Babbage for his machines), but which really hit their stride during the 1890 United States Census, where they were used to input census data. There wasn't a \"program\" per se in this case: cards would be put in a machine and holes would allow wires to touch, completing an electric circuit and incrementing a counter. At the end of a batch of cards, you could look at the counters to see what was tallied. However, since programs are just data, and because data processing equipment using cards was plentiful and well-tested, using cards to store program data became common place. The principle was the same as above: a card would be fed into the computer and a hole would allow an electric circuit to be completed, flipping a bit to \"on\" and storing that word somewhere. Eventually the programmer would say \"go\" and the stored program would be run. The code that a computer executes is called its \"machine code\". The number \"7\" for example, when interpreted as an instruction, might mean \"add the following two numbers together and put the result in memory location 382\" or whatever. Different types of computers have different machine codes, referred to as \"instruction sets\" or \"instruction set architectures\" (there's more to it than that, but that's the gist of it). Programmers used to write machine code directly. They'd put those numbers into whatever format was accessible to the computer. Then in the 1950s, we got the ideas of \"assemblers\", which would let you use \"mnemonics\" (easy to remember names) for instructions. So instead of saying \"7 2 4\" to add two and four, you could say \"ADD 2, 4\" and the assembler program would translate it into the appropriate machine code. Assemblers are just programs themselves, so the first assembler was written in machine code and then the second one would be written in assembler, and assembled by the first one, and from there on out you'd basically pulled yourself up by your own bootstraps. Compilers are the next level up. A compiler translates a (usually more complex-for-the-computer-but-easier-for-the-human) language to another language. Often they transform a language like C or C++ or whatever to assembly instructions or directly to machine code, meaning the programmer can write \"print 'hello'\" or whatever, instead of having to write whatever machine code or assembly the computer needs to write things to the screen/file/whatever. Sometimes the compiler generates machine code for a machine that doesn't really exist, called a *virtual machine*, and an emulator (a program that interprets the instruction set of that virtual machine) is run to interpret that program. This is how a lot of languages work, like Python. (There's a huge variety of compilation and interpretation strategies out there, further complicated by things like \"just-in-time compilation\" and what have you, but that's well beyond the the scope of this answer and at the end of the day is really just details...)"], "text_urls": [[]], "score": [6]}}, {"q_id": "64wb10", "category": "Repost", "title": "Why is the wind from fans cooler than the rest of the room?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dg5izec"], "text": ["This is the same as other forms of wind chill. We are constantly losing body heat to the air around us, and in doing so we cause the air next to our skins to warm up. This heat eventually dissipates, and we lose more heat to the now cooled air. Wind chill speeds up this process by replacing the air around us as we are warming it up, in essence making us feel the \"real\" temperature of the air by blowing away the layer of body-heated air next to our skin."], "text_urls": [[]], "score": [6]}}, {"q_id": "64x3it", "category": "Repost", "title": "Why are photos rectangular not circular?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dg5qrk8", "dg5o5vf", "dg5pbmj"], "text": ["Other's have addressed the fact that the image from the lens is round. Something not covered is that you generally cannot use the entire circular image. The image quality is terrible at the edge (soft focus), and the light falls off (image is darker). So you have to chop some out. Since you have to chop something out, what shape should you choose.... 16 century. You want to paint on canvas. You have to stretch the canvas on a frame. You go to the guy that makes frames and say \"make me a circular frame\". He laughs at you, points at his stock, which is all straight sticks. Why? Because it is easy to cut straight sticks out of a log, and it wastes the least material. Any idiot can cut a straight line, and then with a bunch of straight sticks you can make any size frame you want. If you want a different sized circular frame, that means a different radius, which means a different cut. Instead of storing sticks, he needs to store entire boards, and then custom cut the wood for your frame, and throw a lot of wood away. Your $30 rectangular frame becomes a $450 circular one. Hmm, maybe you'll paint a rectangular painting! Aesthetics. I want to put something interesting in the foreground. In a circular painting, it has to be dead center. So, I don't have a lot of artistic license. In a rectangular one I can put it left, right, near center, or way off. I have choices. Then I need to frame the painting. Frame shop is going to have a lot of straight narrow sticks to make a frame from. It is easy to cut glass and mattes in straight lines, very hard in circles. Do you want to pay $300 for framing, or $2500? By the time cameras were around, images in commerce was a thing. Billboards. Theater posters. Flyers. Cereal boxes. Pages of magazines. Newspapers. Books. All needing images, and a photograph is cheaper than paying somebody to draw or paint something. These objects are all mostly square/rectangular for a multitude of reasons. So, we want square/rectangular images to put on them, mostly. Early cameras did not use film - photographs first went directly on metal. That was the final image. Which is cheaper and easier - cutting a rectangular piece of metal, or a round one, do you think? Soon they went to glass plates for the film. Think it is easier and cheaper to cut glass in rectangles or circles? Which is easier to transport? The cameras were those accordian looking contraptions where you put your head under the cloth. The accordion part was so you could move the film plate closer or further from the lens to focus. It is made of pleated paper/felt. Ever tried to fold paper into a cylindrical accordion? Pretty hard compared to a rectangle. The camera is basically several rectangular frames - one to hold the lens, one to hold the plate, and then the base. Why rectangular - easy to build. And, these were HUGE. If you wanted a 16x20 image, you needed a 16x20 camera. Everything is easiest to make rectangular, so they will be. So you want to carry all this material, only to get a photograph 15\" round? No! You aren't going to throw away parts of the image. Everything is rectangular, so here is your 16x20 image. And so on. Everything makes rectangles preferable, cheaper, and easier in the vast majority of cases.", "Because they're captured on a rectangular segment of a roll of film- or, nowadays, a rectangular array of light-sensitive electronics. This way, it's easier to print the resulting images on rectangular paper, or display them on a rectangular computer or phone screen.", "Let's use a digital camera, as this is simply easier. The image itself is square because that is the shape of the image sensor, which collects the light. The sensor is square, as it is made of millions of pixels, each of which collects and measures the amounts of red, green and blue light to create the colour we see as the image. These pixels are square, so it is easier for millions of these pixels to simply make up a larger square, rather than any other shape. However, the lens is circular. Why, then, does this not create a circular image? As it turns out, the image is circular when it comes out of the lens. The sensor just takes a rectangular image from inside this circle. Check out the \"Image Circle\" wikipedia page, there's a good image. I would link it, but I'm on mobile. So why is the lens circular? Simply put, it's just easier to make a circular lens. Lenses are ground to the correct shape on a lathe, which spins the lens and grinds away material. It would be nearly impossible to do this with a rectangular lens. A square lens would also not bend light in the same way as a circular lens, without more complex shapes. A circular lens alters the light uniformly, while a square has corners and edges. The aperture (iris) is easier to make as a circle, squares are difficult. There's more, advanced reasons why circular lenses are used, but this is ELI5 and you only asked for why the photos are rectangular. Hope this helped!"], "text_urls": [[], [], []], "score": [13, 4, 3]}}, {"q_id": "650c6i", "category": "Repost", "title": "How do televisions measure their viewership ?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dg6fo58"], "text": ["There are survey companies. One is called \"Nielsen\", like \"The Nielsen Ratings\" you might have heard about. By a process of magic, they select your household and send you an envelope. You fill out details about your household: how old you are, how many live there, what kind of shows you like to watch, radio stations... and you mail that back to them. They take that information and enter it into their database. They thank you. They tell you they may call you up and ask you questions, or maybe email you, things like this. Back in the day, the could also send you an electronic box to hook into your TV. This box would register what you watched as you flipped through the channels... and like Windows 10 but nicer, send that information back to Headquarters. So they have a group of people//households giving them information. They compile that information, think \"what if this was everybody\" type of thoughts, and then generate their ratings for TV shows."], "text_urls": [[]], "score": [3]}}, {"q_id": "651j6o", "category": "Repost", "title": "How was a language first translated into another language?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dg6oysp"], "text": ["Point at tree, repeatedly say \"tree\" until the other person says the same word a few times. Rinse and repeat."], "text_urls": [[]], "score": [6]}}, {"q_id": "651ro8", "category": "Repost", "title": "How do the O2 monitors you clip to your finger work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dg6qp9h", "dg6qo09"], "text": ["So those finger clips don't actually measure oxygen saturation. They measure how much infrared light is absorbed by the cells. So let's say you were in a burning building and happen to inhale quite a bit of smoke. The O2 probe would probably read 100% because most of these finger probes cannot tell the difference between oxygen and carbon monoxide.", "The protein in your red blood cells called hemoglobin has a small molecule of iron on it. Hemoglobin carries oxygen in your body, and the oxygen is stuck on that molecule of iron. When the iron has oxygen stuck to it, it's a slightly different color than when it doesn't have oxygen stuck to it. The finger device shines a light through your finger, and the amount of oxygen in your blood determines the color of your blood and thus how the light interacts with it. Sort of. Edit: thumb -- > finger"], "text_urls": [[], []], "score": [3, 3]}}, {"q_id": "6561xo", "category": "Repost", "title": "why is smoking bad for you specifically and emotionally what can it do to your body? How long would it take to smoke for it to hurt your body?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dg7oprs", "dg7qgp7", "dg7pbpk"], "text": ["Gonna assume you mean smoking tobacco. Tobacco smoke contains carcinogenic compounds. These are chemicals that attack the DNA in your cells. 99.9% of the time that just results in the cell dying, and your body replacing it, but a small fraction of cells will become cancerous and start multiplying. Every cigarette is basically playing the cancer lottery. You could get cancer from the first one you ever smoke (*very* unlikely) or you could smoke 50 a day for 40 years and never get cancer (also *very* unlikely). Tobacco smoke also contains tar and other chemicals bad for your mouth, throat, and lungs. Smoking *will* lead to emphysema, and other lung disease, causes high blood pressure, and seriously increases your risk of heart attack and stroke. It also kills your senses of taste and smell pretty effectively. Smoking is never good for you, and it's a habit you should definitely avoid. Trust me. It's inconvenient, expensive, and a total bitch to quit. Edit: Nicotine is a seriously lame drug anyway. You get a little buzz at first, but after you get tolerant to it you get nothing at all except a constant craving to go smoke.", "Imagine you're at a theme park and you get on one of those white-water rapid rides. When the ride ends, what are you probably going to see? Some of the riders are going to be soaked. Some are going to be at least a little wet. And there will probably be at least one person who didn't get wet at all. That's kind of how the negative effects of smoking work on a group. Most people are going to feel some negative effects from smoking over time. Some are going to get drenched in health issues (like cancer). A lucky few will get through unscathed. In both cases, the more you ride/smoke, the greater the likelihood that your luck runs out. I'm oversimplifying, of course, but I think it's a decent analogy. You get on the water ride assuming you'll get wet, not that you'll stay dry. You should pick up cigarettes assuming they'll cause health problems at some point.", "There's no recognized \"lower limit\" to smoking safety, one cigarette is theoretically enough to cause harm. That being said, many of the prominent harms from smoking, increased cancer risk, decline in lung capability, are cumulative effects. So the more you smoke, the greater your risk/harm. But *any* smoking is recognized as a risk."], "text_urls": [[], [], []], "score": [22, 9, 3]}}, {"q_id": "65628x", "category": "Repost", "title": "Why does ribbon curl with scissors?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dg7psd3"], "text": ["When you run the edge of the blade of the scissor over the ribbon, you break the ribbon's structure a little causing one side to be stronger than the other. The stronger side curls the weaker side inward creating the curls."], "text_urls": [[]], "score": [3]}}, {"q_id": "6562ll", "category": "Repost", "title": "How does more viewers or viewers in general(in tv , youtube) convert into money", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dg7osy7"], "text": ["Advertising. Companies will pay other companies to put their products in front of your eyes. more eyes = more money."], "text_urls": [[]], "score": [6]}}, {"q_id": "65663r", "category": "Repost", "title": "Why do men go bald solely on top of the head as opposed to on the sides or on the back?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dg7tzwh", "dg7tax1", "dg85fio", "dg8f2x3"], "text": ["There are different levels of \"why\". There is something different about the hairs in that zone that makes them more sensitive to a particular hormone called DHT. There is a whole series of inflammatory events that slowly kill the follicle. Now, why are the hairs in one spot more sensitive than the hairs in another spot? No one knows.", "The hair on top of the head is more sensitive to the hormones that cause the follicles to shrink in people who have male pattern baldness. This is why hair restoration procedures can implant hair from the back of your head/neck on the top and it will grow like normal hair (it is resistant to what caused the baldness).", "I want to know how everybody else in my family has good hair and I was already mostly bald on top by 17. I shaved my head at 19 when I got tired of fighting it.", "Why can't we grow bald on the back?!?!?"], "text_urls": [[], [], [], []], "score": [181, 34, 19, 3]}}, {"q_id": "6574bb", "category": "Repost", "title": "Anti-aliasing", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dg87hvk", "dg8jsqh", "dg8qpfu", "dg8n5g3", "dg852f8", "dg85xhe", "dg84i29", "dg8o2zs", "dg92h8a", "dg873zt", "dg8bik4", "dg89lwz", "dg88m4m", "dg87vqm", "dg8qgah"], "text": ["**ELI5 Answer** Pixels are all square. That means they are very good at drawing straight lines, but very bad at drawing curved and diagonal lines, because things start looking jagged. Anti-aliasing uses blur and smoothing to hide the jagged edges so that things don't look quite as pixelated. [Here is a good example side by side]( URL_0 ).", "Try taking some basic LEGO\u00ae bricks (let's use some black 2x2 blocks for our example, part #3003) and try to make a diagonal line with them. You'll find the best you can do looks like a staircase with zigzaggy corners. Now step back and squint a bit so your vision is blurry. The further you are, the less you notice the pointy corners. If you were to do the same thing with DUPLO\u00ae bricks of the same 2x2 size and color (part #3437), you'de find a similar effect, but you'de have to be much farther away to make it look less zigzaggy. So how can we get rid of the zigzaggyness? One way, as we saw, is to use smaller bricks (pixels), which allow us to be closer. But there's also another trick you can use. Going back to your original smaller bricks (which are black, on your conviniently white table), start placing grey bricks so that they touch a black brick on two sides. You'll notice the line is bigger, but if you step back and squint, it'll look even less zigzaggy than before. That's because the grey is the color in between the line and the background, which means they blend together better when we look at them. This is a type of antialiasing.", "*I copy-pasted this from an old post I made on /r/pcmasterrace* To understand how anti aliasing works, I'm first going to explain why it is needed. First you need to know what a sample is. ###How images are rendered Imagine your computer is rendering an [image of a tomato on top of a table]( URL_0 ). In order to render the image each of the 1920 \\* 1080 pixels on your screen needs to have colors assigned to them. This isn't as easy as viewing a video or an image. The tomato can be viewed from any angle, and the pixels will need to be recalculated many times every second to produce a smooth animation. A sample is a light/color calculation that can be thought of as an infinitesimally thin ray of light. Imagine that you have a bunch of these rays of light, and pretend these light rays are 1-dimensional objects - lines - that are going straight through your screen. For those familiar with optics this is called normally incident. Most often each pixel will get one ray of light. Most often your computer runs a [single one of these rays through the middle of a pixel]( URL_1 ) (the surrounding pixels in that image are highlighted to make it easier to see the sample). When one of the rays hits an object in the game, it bounces off and goes back through the same pixel it came from, this time with the color of the object it hit. [That ray then determines the color for the whole pixel]( URL_4 ). ###Why AA is needed Now most of the time this works pretty well. If you have two pixels from the same object that are right next to each other - like two pixels on the inside of our tomato - they'll have pretty similar colors and the image will look smooth. However, when you reach the edge of this tomato, [you'll eventually find a pixel is no longer over top of the tomato]( URL_3 ). The pixel on the left will be red like the tomato, but the one to the right of it will be brown like the table it's on. The difference in color is dramatic. The pixels are either on the tomato or not, there is no middle ground. The problem here is that the pixel's don't accurately represent what's going. If you look at the \"pixels\" drawn over [the image of the tomato]( URL_2 ) you'll see that the area covered by the some of pixel has too much information to be conveyed by a single ray of light. On the right half of the pixel there's the table, and on the left half there's the tomato. Other pixels contain significantly less information. The pixels in the upper left corner of the image have fairly uniform colors throughout them, so when they are reduced to a single sample there is less information loss. The solution programmers have come up with this problem is what we call anti-aliasing. The game engine [takes more than one sample per pixel]( URL_5 ) (either one in each corner of the pixel, a few different samples in a grid formation, or sometimes even in random locations). Some will hit the tomato and some will hit the table. The colors are then averaged together to give you your final pixel color. ###Types of Antialiasing The method of AA that's the simplest to understand is called super sampling anti-aliasing (SSAA). It simply takes more than one sample in every pixel on the screen. Because sample calculations take a while to do, this form of AA is extremely taxing on your graphics card. You're essentially rendering the same screen multiple times. Another form of AA is called multi-sampling anti-aliasing (MSAA). This form of AA has an intelligent algorithm that finds out what pixels need more than one sample, and then simply does more samples on those pixels. This form of AA is much cheaper than SSAA and is also a lot more popular. MSAA doesn't work well for all games. Minecraft is the best example of a game where the edges of objects aren't the only thing that needs to be anti-aliased. Take a look at the insides of block textures. The game doesn't blur anything inside of blocks like most other games do, so SSAA is the best option for Minecraft. There are other forms of AA, but these two are the most popular and the simplest to describe.", "Apparently Reddit is full of gamers who tell you nothing of the core concept. So let's start with what aliasing is. Let's say your checking to see how often a light blinks. So you decide you are going to check it every minute to see if it's on. You start the timer and you see that the light is on at the minute mark. Aha.. You say it blinks every minute. But wait... What if it was blinking every 30 seconds... And because you were checking every minute, you only saw every second blink and missed the 30th second blink event. So you say... Fine. I will check every 30 seconds now. And yet the question can be asked... What it was blinking every 15 seconds and you only saw every second and forth blink event? Essentially, you were seeing blinks that were partly determined by your speed of checking for them. You saw 1 when there could have been 2,4,6,8 etc. Blinks in that minute. There is a pattern here which I won't get you but this inaccuracy that occurred is called aliasing. This goes on and on and you eventually reach a conclusion. You can only be absolutely sure of the frequency of something if you check it at least twice as fast as that frequency. This is called the Shannon Nyquist sampling theorem. Anti-aliasing is basically the opposite of this and depending on how complicated the setup of frequencies is, methods to anti alias also change. The fundamental method of anti aliasing is simply check the frequency more often in time or space and hope that you are at least twice as fast as the actual frequency. This is called supersampling. You could do something more complicated. For example. You could check every 10 seconds , and also every 15 seconds. This means you will be able to see blinks if they occur at some point for all multiples of 10 and 15 seconds. That's pretty good. By checking at 2 different speeds, you've sort of reduced the need to go faster for one frequency. This is called multisampling Now in a computer for graphics, aliasing occurs because pixels are processed at a certain frequency, change at another and are displayed at still another frequency. This creates the jarring because of aliasing (you aren't getting all processor produced pixels displayed because you screen refresh is to slow for example). You have to use extra tricks in the GPU to makes sure the image does not get jarred. This is anti-aliasing... Performed by more complicated algorithms of the same basic steps above. Edit : A lot people seem to be assuming that the word \"frequency\" only refers to temporal frequency. It doesn't, your assumption is flawed. Before the \"this is wrong\" comment, I recommend you read up on Fourier analysis. URL_0 and URL_1 These links are definitely not for 5 year olds, but are suitable for the poorly informed tunnel-visioned teenagers who are whining below.", "Depends on the type of antialiasing. They're all very different. MSAA and SSAA work on a pretty simple principle: increase the resolution of the content being rendered. You get more detail that way, which decreases aliasing. SSAA straight up increases the internal resolution of any 3D image. MSAA is more complex and selective, but still works on the same principle. Purely post-process antialiasing techniques like FXAA do not actually change how the picture is rendered at all. It's just a filter overlayed over the image being rendered. Think of an overlay making all colours red. It's that kind of filter. It's just a flat 2D filter overlaying your screen. It doesn't touch any of the 3D rendered model data in any way. Only instead of changing the colour value of all pixels to red it changes their values strategically to try to reduce the colour difference between contrasting parts of an image. This reduces the visual perception of aliasing. There are different hybrid forms of anti-aliasing as well. Some of them are pretty clever in how they achieve their goals.", "Aliasing, in the most general sense, is a concept in the field of signal processing that happens when sampling a continuous signal. Think of a sine wave -- you could sample its value anywhere in time (assuming the time domain is continuous). But if you don't sample frequently enough, you might not get enough information in order to understand the original signal. As a contrived degenerate example, imagine a sine wave with a frequency of 1Hz. If your sampling rate is also 1Hz, you'd see the same exact value every time you sample, and you'd have no way of knowing that the value was fluctuating in between your samples. This concept extends to more complex signals -- by sampling a continuous signal at discrete intervals, you can lose information. ANTI-aliasing, which is what you asked about, is the set of techniques that can be used to mitigate the problems (known as artifacts) resulting from aliasing. If you give a little more info about exactly what application are you are talking about, e.g. computer graphics, I can provide more details.", "Think of two squares touching at corners... the image is quite jaggedy. In things such as video games AA predicts what should be in the empty space to create a smoother images on thing objects (such as wires or lines) or object outlines.", "This Linus tech video covers it. Saw 3 days ago URL_0 TL:DW - pixels are squares like a grid, which makes diagonals shit, so either add more tiny pixels to trick the eye into thinking it is smoother or smooth the colour of the pixels around.", "Aliasing happens when you try to describe something that changes rapidly, and you can't describe it fast enough. For example, imagine you're measuring a half a meter deep hole, and your measuring stick is only capable of measuring in full meters. Whatever measurement you leave with, you've lost information of the real size; you're left with an approximation. The same thing happens in sound. Say you want to measure a 10Hz wave (moves up and down ten times a second), but you are only capable of measuring it five times a second. You'll never get an accurate representation of the true shape of the wave, and anything you come out with is distorted. This is aliasing. The more samples you make, the closer you get to a real representation what the shape truly is. A guy called Nyquist proved that in order to sample a frequency, we need to sample at at least twice the rate. So, anti aliasing is a way of getting around these fundamental issues in what happens when we lose information in our signals. With pixels for example, the square edges introduce such a harsh transition that we lose information of what goes on between the pixels. An interesting way of reducing this effect includes sub pixel anti aliasing, where you take advantage of the fact that each pixel is comprised of a discrete R, G, B value, smaller than the pixel itself and therefore capable of generating higher 'spatial' frequencies. It has been proven that you can share these colour components with neighbours to try and spoof the missing information, producing what appears to be a much higher quality image.", "Screens are grids of rectangular dots called \"pixels\"; they're pretty small, but they're still _waaay_ too big to perfectly show curved or even just \"crooked\" shapes. This is most noticeable when computers are drawing shapes; if I draw a circle using only those dots, it'll look jagged. That's called _aliasing_. Humans don't expect their smooth shapes to look jagged, so aliasing makes computer-generated images look less real. _Anti-aliasing_ is a term for techniques you can use to trick people into not seeing as much of that jaggedness. One technique is to trace around the outside with \"lighter\" (less-saturated) versions of the color of the edge. This creates an optical illusion of \"blurriness\" which tricks us into thinking the edge is smoother and less jagged. And less-jagged images look more realistic to humans.", "Aliasing is a duplication of signals that occurs when a signal is digitized. In the real world, signals like sound and light are *analog time continuous*. This means that their values can take any value at all. For example, a sound signal might have a maximum loudness, or intensity of 99.579 dB, and a frequency of 15 kHz. You can think of a wave as a collection of infinite points, that all together make a continuous wave. Because computers are digital, they can only take a certain amount of point from this wave. Computers measure the intensity, or sample the wave, at a certain rate, to measure the signal. This rate is called the sampling rate. If the sampling rate over twice our frequency, say, ~~20~~ 40kHz, then our signal of 15 kHz can be reconstructed pretty accurately. However, if we have a sampling rate of~~10~~* 20kHz, we will start running into problems. Because the sampling rate is less than our signal, it cannot accurately measure it. The signal reconstructed by our computer will be distorted, and will look like a lower frequency signal, or an *alias*. (will add a picture later for clarity) In order to fix this, frequencies higher than twice our sampling rate are simply blocked. In music files, the sampling rate is about ~~26~~ 44kHz, which means a maximum audible frequency of 22kHz. Since the human hearing range tops out at 20kHz, it doesn't matter that these high frequencies are blocked out, because we can't hear them. Edit: Thanks to /u/ipwnmice and /u/oonniioonn for some corrections.", "Imagine pixels as a bunch of squares covering a perfectly smooth image. How do you color the pixels so they look like the image underneath? You could color each pixel according to the color of the image exactly at its center. But what if there's detail smaller than the pixel, and you happen to hit a small detail that doesn't represent the color of the whole pixel? You'll color the whole pixel like that small detail, and it will have a color that's mostly wrong. Really what you want is the *average* color of all the details inside the pixel. That means that all the details smaller than a pixel get smoothed out. This makes the image look better and smoother, and can also prevent pixels from blinking on and off as the centers move over small, high-contrast details. It's very hard to *exactly* compute the average, so must anti-aliasing techniques work by measuring the color at multiple specific locations inside each pixel, and mixing together the results. The way you mix things (i.e. [weighting locations differently]( URL_0 ) according to whether they are near the center of the pixel or far away) can affect the perception sharpness, or the brightness of fine details like highlights.", "So there are a bunch of different techniques for anti-aliasing, but there are two main categories: render-time AA and post-process AA. **Render-Time AA** - These techniques are applied *during* the render of the scene. As pointed out elsewhere, one of the main ways of doing this is by super-sampling, or drawing the scene at a higher resolution before down-sampling it to the display resolution. This can fix both [jagged edges]( URL_2 ) and thin lines disappearing. Nvidia's [page on DSR]( URL_0 ) does a pretty god job of showing how super-sampling helps with both of these. One of the most important differences is that render-time techniques get to use information about the 3d geometry of the world, and only smooth things like the edges of polygons. **Post-Process AA** - These techniques are applied *after* the whole scene has already been drawn. The input to these is just the \"finished\" 2d image. The most common post-process AA is FXAA. The basic idea of these is to look at neighboring pixels and look for big changes in neighboring pixel color. These indicate hard-edges, which are where aliasing occurs. [Here]( URL_1 ) is an image showing the edge-detection steps of FXAA. Once you detect those edges, you can blur them a little, hiding the aliasing. Post-process AA is super easy to add to your game, because you just stick it on at the very end of your render pipeline. Just make sure to apply it before you add in your UI, because all those hard edges in the text and boxes will come out blurry. The problem with post-processes is that it doesn't know if a hard edge is *supposed* to be there. It may end up blurring some of your textures, especially if there is text on them.", "Pixels are square, and solid colored outlines look jagged if the squares aren't small enough. Anti-aliasing corrects this by adding steps of transparent color near the edge to create the illusion of a smooth surface. Here's a [diagram]( URL_0 ) I made to show you with and without anti-aliasing.", "Followup question: ELI5 Anisotropic Filtering? I mean, I know what it does (make surfaces you look at a small angle be less blurry), but my question is, why are they blurry to begin with and require extra filtering, if the same surface looks non-blurry if viewed at a direct angle."], "text_urls": [["https://qph.ec.quoracdn.net/main-qimg-10856ecbea4f439fb9fb751d41ff704a"], [], ["http://i.imgur.com/Y4gW0Qu.png", "http://i.imgur.com/IG9pbks.png", "http://i.imgur.com/rc3wMbi.png", "http://i.imgur.com/xSFk13p.png", "http://i.imgur.com/SK1vYX4.png", "http://i.imgur.com/ip01OiT.png"], ["https://www.cs.auckland.ac.nz/courses/compsci773s1c/lectures/ImageProcessing-html/topic1.htm", "http://homepages.inf.ed.ac.uk/rbf/HIPR2/fourier.htm"], [], [], [], ["https://youtu.be/hqi0114mwtY"], [], [], [], ["https://en.wikipedia.org/wiki/Window_function"], ["http://www.geforce.com/hardware/technology/dsr/technology", "https://i.kinja-img.com/gawker-media/image/upload/t_original/18j12dtou8x64jpg.jpg", "https://people.cs.clemson.edu/~tadavis/cs809/aa/aliasing2.png"], ["http://i.imgur.com/p9DRVfj.jpg"], []], "score": [5377, 2946, 837, 127, 91, 51, 43, 9, 8, 7, 6, 4, 4, 3, 3]}}, {"q_id": "659prn", "category": "Repost", "title": "Why can't we create infinite energy with something like this?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dg8kpuh"], "text": ["This is called a perpetual motion machine, where the energy you give in is less than the energy the machine gives out. I'm too inexperienced to answer this, but [this video by Tom Scott]( URL_0 ) debunks it and it features your machine (well a variant of it) also!"], "text_urls": [["https://www.youtube.com/watch?v=EiZU3BvqvP4"]], "score": [4]}}, {"q_id": "65apmw", "category": "Repost", "title": "why atomic bombs make mushroom clouds", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dg8stpq", "dg8t15q"], "text": ["It's not just atomic bombs that produce these. Other bombs do as well, just to a smaller extent. It occurs because the core or center of the explosion has a very high heat intensity. As the heat rises it picks up debris and carries it into the air. As the hot air cools it begins to dissipate creating the mushroom effect.", "Energy release - > big boom fireball - > hot hot - > expands, starts to rise - > creates vacuum - > more air come in - > they rise too - > keep rising until the air on the top is like \"you shall not pass\" - > so the boop shape on the top"], "text_urls": [[], []], "score": [11, 9]}}, {"q_id": "65b9pl", "category": "Repost", "title": "Why does your mouth water before you throw up?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dg8wlzq"], "text": ["It's a reflex to protect your mouth. Vomit is very acidic and can cause damage to your teeth and the soft tissue in your mouth (and esophagus too). Healthy saliva is neutral (neither acidic or basic) so it helps buffer the acid in vomit. By /u/thejennadaisy URL_0"], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/37stwa/eli5_why_does_my_mouth_water_before_i_throw_up/"]], "score": [4]}}, {"q_id": "65bwma", "category": "Repost", "title": "Out of all the human beings, living and dead, why in this particular body did I have my consciousness?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dg90k30"], "text": ["Well, you had to turn into someone. Turns out you turned into you. It's not that YOU were predetermined to be, it is not that you were before or will be after. It is simply because your body has a brain and that brain experiences consciousness and that consciousness happens to be you. Every person has to be someone."], "text_urls": [[]], "score": [6]}}, {"q_id": "65c5p2", "category": "Repost", "title": "why do hackers want to use linux os even though it's easier to use windows or mac OS?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dg922zu", "dg92d42"], "text": ["Once they get through the learning curve it is easier to use linux. Besides, linux is free. The other two will cost eventually.", "Linux is generally far more customisable and it's far easier to change things, test out ideas, etc. Also you're less likely to get viruses."], "text_urls": [[], []], "score": [4, 3]}}, {"q_id": "65dhh5", "category": "Repost", "title": "Why does pulling a ribbon across the edge of a pair of scissors cause the ribbon to be curled?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dg9cqyg"], "text": ["When you run the edge of the blade of the scissor over the ribbon, you break the ribbon's structure a little causing one side to be stronger than the other. The stronger side curls the weaker side inward creating the curls."], "text_urls": [[]], "score": [7]}}, {"q_id": "65ej9i", "category": "Repost", "title": "How do people figure out what colors to use when coloring an old black and white photo?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dg9mnc3", "dg9p24u"], "text": ["\"Black\" and \"white\" are actually a ton of different shades of grey. If you know the method the picture was taken with and how it converts visible light into something that can be put onto film in greyscale, you can tell with a pretty high degree of accuracy which shade of grey corresponds to which visible light color.", "Historical perspective, contextual clues, hues and saturations, going with \"expected colors\". The sky is blue, the grass is green, cement is gray. Certain militaries wore certain colors, we have their uniforms today. Once you get through the \"basics\" and what we expect to see, you have quite a bit of info there. Then the other clues can help fill that in. All the colors may not be perfect, but there is still plenty of information in a photo to get buy and colorize it."], "text_urls": [[], []], "score": [8, 3]}}, {"q_id": "65fe4x", "category": "Repost", "title": "Pee shivers", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dg9vfq5"], "text": ["No one can explain this like you are five because this is an open, unanswered scientific question. Some people believe that your body temperature drops when you expel warm liquid, which is contradicted by the fact that you don't experience the same thing when you vomit, shit or donate blood. (Leaving out the Oxford comma for the fun implications). The most scientific explanation that I found had to do with the idea that when you switch from continence mode to free flowing, there is a switchover from sympathetic to parasympathetic nervous system activation and somehow this switchover causes the shivering. Seriously, though, if you answer this question, you're probably a candidate for the igNobel."], "text_urls": [[]], "score": [13]}}, {"q_id": "65fs5q", "category": "Repost", "title": "long division. i'm now 30 nobody has ever been able to explain it to me. also long multiplication", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dg9y4qd"], "text": ["Let's say you have 573.5 and want to divide it by 25. First, you know 25\u2022**2**=50, so 25\u202220=500. That leaves 73.5 left over. Now 25\u20223=75, so close, but a little too high, so we know it has to be between 2-3. 25\u2022**2**=50 - > 73.5-50 = 23.5 Now, 23.5 is a bit less than 25, so we are gonna deal with decimals. To make things easier, let's times it by 10, making it thus 235. If we had to guess, 25\u2022**9** should get us pretty close, it actually gives us 225. Now we have 10 left (actually 1 because we timed by by 10). Now, 10 is less than 25, so let's times it by 10 again (making it now times 100), giving us 100. This should be easy, 25\u2022**4**=100. **Answer:** 22.94 In long division notation, the process should look like this: 2 \u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014 25| 573.5 -500 \u2014\u2014\u2014\u2014\u2014\u2014\u2014 73.5 \u2014\u2014\u2014\u2014\u2014\u2014 22 \u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014 25| 573.5 -500 \u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014 73.5 -50 \u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014 23.5 \u2014\u2014\u2014\u2014\u2014\u2014 22.9 \u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014 25| 573.5 -500 \u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014 73.5 -50 \u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014 23.5 -22.5 \u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014 1.0 \u2014\u2014\u2014\u2014\u2014\u2014 22.94 \u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014 25| 573.5 -500 \u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014 73.5 -50 \u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014 23.5 -22.5 \u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014 1.0 -1.0 \u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014 0 Obviously you this is all a single workout, but I had to show the process in text. For even better visualization: 20.000 \u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014 25| 573.5 -500 \u2014\u2014\u2014\u2014\u2014\u2014\u2014 73.5 \u2014\u2014\u2014\u2014\u2014\u2014 22.000 \u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014 25| 573.5 -500 \u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014 73.5 -50 \u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014 23.5 \u2014\u2014\u2014\u2014\u2014\u2014 22.900 \u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014 25| 573.5 -500 \u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014 73.5 -50 \u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014 23.5 -22.5 \u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014 1.0 \u2014\u2014\u2014\u2014\u2014\u2014 22.940 \u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014 25| 573.5 -500 \u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014 73.5 -50 \u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014 23.5 -22.5 \u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014 1.0 -1.0 \u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014 0"], "text_urls": [[]], "score": [7]}}, {"q_id": "65hc8h", "category": "Repost", "title": "Why do guys get post jerk off guilt syndrome?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dgaa9wg", "dgaal56"], "text": ["Post-orgasm your body quickly loses dopamine (chemicals which make you feel good which you get during orgasm) as it returns to its normal state. This quick loss of dopamine makes you feel a lot less happy than you were a few seconds ago, making you feel sad or guilty.", "Sorry I can't help but I find this weird. Is it normal to have post jerk off guilt? I don't think I've ever had it."], "text_urls": [[], []], "score": [5, 3]}}, {"q_id": "65if0u", "category": "Repost", "title": "How binary code works?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dgair4m", "dgal1lx"], "text": ["Binary code is just another way to count. Instead having 10 digits, you only have two. In the 10 digit system, every digit to the left is the digit times 10^n (where n is the number of digits to the right, starting at 0). So the decimal number 4711 is basically 1 * 10^0 + 1 * 10^1 + 7 * 10^2 + 4 * 10^3 = 1 + 10 + 700 + 4000 = 4711. The binary system shifts everything times 2^n, so 1011 = 1 * 2^0 + 1 * 2^1 + 1 * 2^3 = 1 + 2 + 8 = 11. You can tell a system (like a computer) to interpret certain combinations of 0 and 1 as a code. For example, ASCII (the first usable text interpretation code) is a 7-digit binary code where every combination is one symbol (printable and non-printable), resulting in 128 possible symbols. For example, the ASCII code 1000001 is 1 + 64 = 65 in decimal and represents the symbol 'A'.", "I'm currently a Computer Science major, and Computer Organization was my most recent course. Binary inside computers is like math with different rules. We manipulate the properties of it to do very complicated things. ~**The basics of binary:** Binary is, at its heart, a different counting base. Normal people count with Base10, where each place (ones, tens, hundreds) is simply a number multiplied by its base...Ten to a power. Base10 gets its name from having ten digits: 0,1,2,3,4,5,6,7,8,9. How Base10 works: 534 = 4x10^0 + 3x10^1 + 5x10^2. Binary, instead of ten numbers, works with two: 0 and 1. So the binary number 1111 isn't one thousand one hundred and eleven in binary. It is: 1111 = 1x2^0 + 1x2^1 + 1x2^2 + 1x2^3 1 + 2 + 4 + 8 = 15 This is how we count in binary. The whole power thing gets complex, so you usually pick up the powers of two. From right to left, you can label the bits 1, 2, 4, 8, 16, 32, 64, 128, 256.....Etc etc etc if that helps. ~**The Intermediate of Binary** So, now we have a grasp of WHAT a binary number is: it's just a number, represented in Base2 instead of Base10. How can we manipulate it? Well, arithmetic is a nice thing to do! Let's cover the basics. Adding 2 binary numbers: 1010 ... AKA Ten in Base10 0011 ... AKA Three in Base10 --------- 1101 ... AKA Thirteen in Base10 The numbers get added just like you remember from Base10. 0+0=0. 0+1=1. 1+0=1. 1+1=0 carry the 1. Multiplying 2 binary numbers: For the sake of staying near ELI5, we're going to do the easy multiplication: Multiplying something by 2, 4, 8, etc. Think of what happens when you multiply by ten in Base10. 6 becomes 60. 745 becomes 7450. Everything just shifts left one. Binary is no different when you multiply by 2. 01001 -- > 10010 Multiply by 4? Everything shifts twice. 001101 -- > 110100 ~**The Harder Levels of Binary** So now we know that Binary is a number system...And it has mathematical operations. However...Binary is also conveniently an easy way to control switches. One and Zero can count....Or One and Zero can be On and Off....Or One and Zero can be both. If I have 4 LEDs (lights) in a row on a breadboard, I can describe their states in binary. 1 0 0 1 On off off on. Computers use binary in this way as well. It can count, it can catalog, and it can serve as simple on/off. It will use a certain string of binary (example, 0111) sent to a certain place at a certain time to signal that something is being pulled from RAM. It will then use binary to define the address (think of how we define RAM. 512KB? That's stored in binary. See how it's a convenient 2-multiple?). The value stored at that address is a binary number. *How* this binary string is used depends entirely on context. You could be adding. You could be controlling switches. You could just be feeding into a complicated logic diagram of ANDs, ORs, XORs. It all depends on the context. As far as what binary physically does inside a computer....It just activates transistors - microscopic switches. It's boring and repetitive on an eli5 level..But oh so fascinating on a collegiate level. If you want to learn more about that: find an online Computer Organization course. It will teach you everything you want to know about computer basics. Binary logic - > Logic gates - > Solid State Machines - > Processors - > Memory (to include building memory gates) - > Registers - > etc. ~**Some fun facts:** 1 binary digit is a bit. 8 binary digits are a byte. 4 binary digits are a nibble. Hexadecimal numbers are just a bunch of nibbles (2^4 = 16). When you see a MAC address, an ugly default router password, or an IPV6 address, it's just a shorthand, eye-friendly way of showing you a humongous binary number (4 bits for every character)."], "text_urls": [[], []], "score": [4, 3]}}, {"q_id": "65j997", "category": "Repost", "title": "How do glass and other transparent materials work on a molecular level? Do they have more space in between molecules? Does the light interact a lot less with their molecules? How does the light come through where in other materials the light is absorbed?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dgauj5h", "dgavccp", "dgb69ba", "dgbcf86", "dgayopa"], "text": ["Glass does absorb light, but not in the visible spectrum. Molecules have molecular energy levels for their electrons (and atoms also have atomic energy levels the same way). When they absorb light, the energy of the light matches the energy difference between the energy levels, and an electron is promoted to a higher energy level. It just so happens that typically, the molecules in glass (mostly SiO2) don't have a difference in energy levels corresponding to the energy of visible light. They do happen to have a difference in energy level that corresponds to light in the UV spectrum, hence UV light does not pass through normal glass very easily (unless it's pure SiO2). This also means you're unlikely to get a sunburn in your car with the windows up. It also happens that the glass molecules are generally not the right size or shape to scatter visible light either very much. However there is some light reflected from the surface because glass has a different refractive index than air (ie. light travels slower through glass). At any boundary where there is a refractive index change, some light will usually reflect (see the Fresnel Equations). Hence if the surface of the glass is not smooth, it will reflect light in many directions, and it will effectively scatter light at the surface. EDIT: like Mariofosheezy pointed out, also remember that most matter is not very dense, most of the volume is made up the \"electron clouds\" hence if the molecular orbitals of the glass don't interact much with the light, then it is basically passing though 99.9% empty space as far as it's concerned. EDIT2: It get's more complicated than this. Many other materials have other properties that make it so that visible light can't really pass through. Some have very good absorbance in the visible spectrum, others have very densely packed molecules/atoms that attenuate light very rapidly, etc.", "The interactivity, attenuation, and refractive index of a material varies with the frequency/energy of the emr. Glass is mostly non interactive with visible light but will usually absorb infrared and ultraviolet light. Your cellphone still works indoors even though you can't see through walls. [Here is a stove top that is opaque to visible light but transparent to an infrared camera]( URL_0 ) A photon needs to be able to excite a molecule in order for it to be absorbed so it would need to have an energy near the band gap of its electron's next highest level or able to rotationally excite the molecule. Density matters some but only as it places more matter for light to travel through and the same effect could be achieved with a thicker window of less dense material.", "Essentially the answer is one of your suggestions. The light interacts less with the molecules. Detail below: First, we need to understand that light is weird. It's neither strictly a wave, nor a particle. Under certain metrics it behaves like one or the other. This is called the \"wave-particle duality\". When referring to light when it behaves like a particle we call it a photon. Next, light of different colours has different wavelengths. Each individual photon has a specific wavelength, and light is essentially made up of a constant stream of photons. Smaller wavelengths are more energetic (this may seem counterintuitive when first introduced to the concept but you can think of a smaller wavelengths as vibrating faster). Blue has a smaller wavelength than red, thereby giving it more energy per photon. Similarly, ultraviolet has more energy then blue. The spectrum of light ranges from radio waves (1km+) to gamma rays (1nm-). The smallest wavelengths are incredibly energetic, enough to break apart chemical bonds and can even cause damage to a person's DNA. Visible light is approximately in the 500-1000nm range. When an opaque object is struck by these photons, the energy is absorbed. For each photon absorbed, a corresponding electron is bumped up to a higher energy state. The \"space\" where that electron used to \"fill\" is called a hole. These holes generally want to be filled again with electrons. After a very brief delay (incredibly brief for almost all materials), the electrons that are energized \"fall\" back into the hole. When this happens, they are no longer in a high energy state and need to expel the excess energy that they absorbed earlier. Depending on from what energy level they fell from, different amounts of energy needs to be expelled. This energy is released as new photon. However, the electrons don't fall back down in one step. There are only certain ranges of energy levels that electrons are allowed to be in (depending on atomic/crystal structures). This is different for every material. The electrons falls back down in a few steps and emits a photon for each jump down. For many objects, the energy between these gaps results in photons that have an energy level that puts them in the visible spectrum. Some have multiple jumps in the visible spectrum, and to the human eye they'll appear white or brown or some other \"non-rainbow\" colour. Now let's look at transparent objects. In glass (SiO), the bands of allowable energies that the electrons can have is quite limited. When a photon strikes the glass, it wants to give it's energy to an electron so it can jump up in energy levels. However, since the gap between allowable electron energies is so large, there would be nowhere for such an energized electron to go. Thus, the photon does not get absorbed and remains the same colour as it entered the glass and passes through unchanged in wavelength. (A percentage of photons may change direction due to reflection/refraction, but the colour remains the same) Photons that have a higher energy level may be able to overcome this bandgap. They will be absorbed and re-emit new photons just like if the glass were opaque. However, this isn't within the visible spectrum and can't be seen. Sidenote: The energy absorbed when the photon strikes an object doesn't have to ALL be re-released as new photons. It can also create \"phonons\" which are essentially molecular vibrations that increase the thermal energy (heat) of the object. That's why objects that don't re-emit the light (appears black to the human eye) get hotter when exposed to light.", "Professor Moriarty explains it well in [this]( URL_0 ) video. He is a photon trying to get through his office, there are lots of ball pit balls on the floor (atoms). He wants to move them onto the shelf. If he manages to move the balls he uses his energy to move them off the floor and doesn't get through the room. If the shelf is too high to reach (the energy gap is too great) he doesn't move any balls and continues through the room and gets out the other side.", "It's best to think of light in terms of waves for this. If ray of light hits a molecule, it will absorb part of it and emit another ray of light in the same direction as it usually can't absorb it. However the time it takes for the molecule to re-emit the wave varies. If a molecule re-emits the wave fast enough, it will appear that nothing has changed, and the light just passed through. If a molecule is too slow to emit, the new wave might vibrate in the opposite direction to the old wave, hence reducing the amount of light getting through. If the material is thick enough, no light will pass through at all, such as in wood."], "text_urls": [[], ["https://www.reddit.com/r/mildlyinteresting/comments/58781h/my_infrared_game_camera_can_see_through_my_stove/"], [], ["https://youtu.be/Omr0JNyDBI0"], []], "score": [206, 18, 11, 7, 3]}}, {"q_id": "65lcda", "category": "Repost", "title": "If two or more items are plural, and one item is singular, why is zero items plural?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dgb5q8v"], "text": ["Because singular is only one item. Zero isn't one, therefore it is plural. It may be intuitive to think of plural as being \"more than one\" but it isn't like that."], "text_urls": [[]], "score": [3]}}, {"q_id": "65ls1n", "category": "Repost", "title": "When someone is given the death penalty, why are they on death row for so long?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dgb9gz3", "dgb9g1l", "dgbwjzb"], "text": ["There's an appeals process that has to be followed, and that can take years because the courts are really very busy. Then there's the fact that issuing stays of execution is a very easy, low-cost way for governors to earn brownie points with more liberal constituencies who understand how many innocent men have danced the sisal two-step because the State was in a rush to punish someone.", "There's a line for appeals, they have the right to challenge the ruling and exhaust their options. Then it comes down to the state and its resources; timing the executions. It can take a very long time to do all of this, years and years.", "As NarnBatSquad and HappyShrapnel said, it all comes down to resources, legal avenues of appeal, and the long, long list of people that are already there. Many that are on 'death row' are actually awaiting a new trial or hearing; one of the West Memphis Three was on the Last Mile for 18 years, fighting for a new hearing, because his initial conviction was pretty much a show trial. Incidentally, while the 'last meal' for a death row inmate is simply a custom, and not a requirement or obligation, most prisons have stopped following the tradition because inmates regularly abuse the 'last meal' custom by ordering huge amounts of food that they can't possibly finish."], "text_urls": [[], [], []], "score": [4, 3, 3]}}, {"q_id": "65mvpz", "category": "Repost", "title": "What is dust?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dgbjdmq"], "text": ["Skin particles, human/animal fibers, minerals of various types, pollen, etc. The type of dust you encounter/inhale depends on the type of environment you're in. For example, you'll obviously inhale more paper fibers in a carpenters workshop than in a kitchen or some other random area."], "text_urls": [[]], "score": [4]}}, {"q_id": "65oled", "category": "Repost", "title": "Dark Matter", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dgbxlbp"], "text": ["The laws of gravity are exceptionally well understood. They tell us exactly how an object of some mass should move around. On a cosmic scale we use Einstein's general theory of relativity to do this. All the major predictions of general relativity have been shown to be correct, so we are exceptionally confident that this is the right theory of gravity for our Universe. That being said, when we look at galaxies, we find that they don't move in accordance with our predictions from the law of gravity, based on all the mass we can see in them. We find that they rotate far too fast - if there was only the mass we could see, they should be breaking apart, yet they are still held together\u200b. Since we're exceptionally confident that our description of gravity is correct, it's only logical to assume that there must be some unseen mass. We call this dark matter. What is dark matter made of? We don't know. Leading theories suggest a new type of particle, that interacts via gravity and the weak force but not electromagnetism (which is why we can't see it). We call these hypothetical particles weakly-interacting massive particles, or WIMPs. Experiments are underway to try to detect them but so far we haven't found any. Particle theorists are also coming up with theories to predict what these new particles should be, but they are also having trouble. There are other ideas as to what dark matter could be, and some mavericks do suggest that our theory of gravity may be wrong, which is possible but unlikely given it's success in other areas."], "text_urls": [[]], "score": [12]}}, {"q_id": "65p4p6", "category": "Repost", "title": "Why do we seem to look different in mirrors compared to photos and such?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dgc1kms"], "text": ["because mirror image is flipped (mirrored), in other words mirror image is just how you see yourself (your perspective of 'you'). Whereas photos aren't flipped and display yourself as it is, in other words, you in a photo is how other people see you."], "text_urls": [[]], "score": [5]}}, {"q_id": "65pmyr", "category": "Repost", "title": "Muscle Growth", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dgc5hgd"], "text": ["When you lift weights you're actually creating tears in the muscle tissue. The tears heal and create scar tissue on the muscles. That scar tissue is what causes muscles to grow."], "text_urls": [[]], "score": [4]}}, {"q_id": "65qyii", "category": "Repost", "title": "How did different languages start and how did people who first encountered new civilizations learn the languages?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dgch22x", "dgcgy9b"], "text": ["The relationships are quite complicated. [This great graphic]( URL_0 ) goes a good job of showing the connections.", "Languages started through basic communication. Arbitrary sounds that related to a specific thing. Those naturally evolve over time and become more efficient and complicated at the same time. As for translation, they would have to start with common ground. Say you pick up a rock and say \"rock.\" You could establish how to say rock in both languages as long as the other person realizes you mean to communicate, which is pretty easy to determine. Have you ever tried to communicate with someone who didnt speak your language? Its the same process."], "text_urls": [["http://mentalfloss.com/article/59665/feast-your-eyes-beautiful-linguistic-family-tree"], []], "score": [3, 3]}}, {"q_id": "65r28y", "category": "Repost", "title": "What do the bunny and eggs have to do with the resurrection of Jesus Christ?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dgchthn", "dgchre4"], "text": ["Nothing. Not even as much as Santa and Christmas. Spring fertility celebrations go way back into pagan days, and the new religions tried to fold in the things people enjoyed - it's good marketing.", "They are all pagan rituals adapted to Christian mythos to increase the amount of believers."], "text_urls": [[], []], "score": [4, 3]}}, {"q_id": "65rong", "category": "Repost", "title": "How do amplifiers work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dgcodlg", "dgcopmy"], "text": ["This explanation depends somewhat on knowing basic electronics concepts. A transistor is a unit with 3 connections only. One is a pathway for current out of the transistor, usually ground. One is for controlling current. The last one is connected to a higher voltage, which is the source for current. If you expose the control to a changing signal, you'll get a changing amount of current flowing through the transistor. Technically, a certain type of amplification is already occurring. But we usually start with voltage and want to end with voltage. One way to achieve this is for the transistor to draw its current through a resistor, which will produce a changing voltage thanks to the fundamental relationship between current and voltage passing through a resistor. The problem is, this is a changing amount of current flowing in one direction. We usually want current flowing in both directions, alternately, for a signal like music playing through headphones. In short, you use an assortment of transistors passing electricity in one direction only *within each one*, but in opposite directions to other ones in the circuit. It takes some complex and clever design, but you get it balanced right and you can create current flow in both directions, just like your original source. A helpful tool is that you can make \"backwards\" transistors that control flow with a controlling signal that is compared to the high voltage, not low. Going into much more detail gets into \"take a class\" or \"read an intro to EE\" textbook levels of explanation, but that's the basic idea. Transistors take small signals and make them big. Hook them together right and you can get them to take the signal you need to use and produce a bigger one of the right type.", "In general terms, an amplifier is a system where a small change in the input causes a big change in the resulted output. For an analogy, think about the flow of the river through a dam. When the dam is closed no water can pass through, but if we raise the damn just a few centimeters, a large amount of water from the river behind him will start to rush in. The electronic vacuum tube or the solid-state transistors in your amplifier are working in a similar fashion. Without getting into the physics behind their operation, you can think of an amplifier as a set of vacuum tubes or a set of transistors, acting as dams and directing the flow of electricity from the main power supply to your headphones or speakers. A small change of current at the base of the transistor will result in a big change of the current that pass through him from the supply to the output."], "text_urls": [[], []], "score": [11, 3]}}, {"q_id": "65rxjw", "category": "Repost", "title": "Why is it that you have to look right next or past an object in the dark to see it rather then just looking at it directly?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dgcq43g", "dgcpnhq"], "text": ["This is a result of the structure of receptors in your eye. The cones in the center are more sensitive to color and details, while the rods which are used for peripheral vision are more sensitive to light and movement. So looking sideways allows you to observe the darker object around you.", "Rods and cones :D Rods are much more sensitive to low light than cones are so most (all?) low light vision is with rods. There are far fewer rods at the center of your vision than elsewhere on the retina so you see far less low level light there. URL_0 > \"If you see a dim star in your peripheral vision, it may disappear when you look at it directly since you are then moving the image onto the cone-rich fovea region which is less light sensitive. You can detect motion better with your peripheral vision, since it is primarily rod vision.\""], "text_urls": [[], ["http://hyperphysics.phy-astr.gsu.edu/hbase/vision/rodcone.html"]], "score": [5, 5]}}, {"q_id": "65tltt", "category": "Repost", "title": "Brexit", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dgd6ra0"], "text": ["EUROPE! Post WWII they all play nice and friendly. They form the European Union. ([And the Eurozone, Council of Europe, Schenzen zone, OMG SO MANY AGREEMENTS]( URL_0 )) Anyway, they're friends, they come together, they trade, travel, and all play along. Like how the states in the USA play nice... but without the big giant federal government enforcing it. A group of people in the UK don't like the how they're getting treated, don't want to play nice, and want to leave the EU. To appease them, Prime Minister David Cameron says they'll have a referendum on the matter in a few years. It's a special vote. Like, \"hey people, should we leave the EU\". People in London, Scotland, and N. Ireland voted to stay part of the EU, the country bumkins voted to leave. They get 51%. Cameron steps down. Theresa May becomes to new Prime Minister (it's like our president). And... it looks like it's happening. A lot of deals are being undone, rules enacted, but at least they never switched to their money to the Euro, so that's not a mess. So... Why did they want to leave the EU? That's a tough one. And you'll get a lot of political opinion that's only marginally associated with the truth on the matter. From both sides sadly. There are parallels between the Brexit vote and the victory of Trump in America. It's the effect of the rise of the [UK Independence Party]( URL_1 ). Both were rural, right-wing, mostly white, somewhat nationalistic, opposed multiculturalism, opposed immigration, and appealed to populism. Oh hey, tax cuts and climate change denial are both in there too. The two movements are quite similar. If you're looking for a \"why\", then pretty much every explanation you've heard for the Trump presidency applies to Brexit too. Something something, populist nationalism, disenfranchised working class, blaming immigrants, fight elitism. I personally blame automation taking away the jobs and growing inequality as seen by the GINI coefficient. But it's a lot easier to get people to vote for you if you have a more familiar scape-goat, and historically everyone hates immigrants. Imagine if Trump got elected as governor to Texas on the platform of separating from the USA. And that was legal and currently in the works. It's a lot like that."], "text_urls": [["http://cdn1.vox-cdn.com/assets/4719042/Supranational_European_Bodies.png", "https://en.wikipedia.org/wiki/UK_Independence_Party"]], "score": [3]}}, {"q_id": "65ubl2", "category": "Repost", "title": "Who decides if art is 'good' and what it's worth?", "title_urls": {"url": []}, "selftext": "I remember reading a few years ago that a painting of a black dot on a white canvas sold for millions of dollars. Who actually decides if an art piece is actually any good?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dgdaghw", "dgda09v", "dgdksqs"], "text": ["Usually it's based on the body of work of the artist. For example, by the end of his work life Joan Mir\u00f3 was placing a single stripe of paint on a canvas and these are very prized even though *anybody* could place a stripe of paint on a canvas. Like he'd stare at the canvas for a while and then in one fluid movement put a single stroke down and he'd love it and everyone else would love it. This is because he spent his whole life evolving from being a talented painter that you'd probably call \"normal\" (i.e. he made pretty pictures with paint) to becoming a more and more abstract painter. He kept reducing the complexity of his forms to see how to express emotions and form in an ever increasingly abstract way so that after decades of doing this he had developed a kind of language of form that was uniquely his. So if you're aware of his progression and have an understanding of how to \"read\" his abstraction you can see how his single stripe of paint has meaning and is different and special compared to a stupid stripe of paint that just *anyone* could do.", "If someone wants it they'll buy it. If someone else wants it more they'll pay more for it. Eventually you've got an expensive work of art. As for why people want it, preferences are impossible to determine across a population.", "This is what we mean when we say \"market forces\". So there is no single person or organization that decides what is worth what. A thing is worth as much as someone else is willing to pay for it. That dot sold for what it did because someone else was willing to pay that much for it. There is no central authority that sets prices for art. The question is, why would someone pay that much for a dot painting. And the answer is complex. Could be that they really liked the dot and really hated money, but likely not. A better answer is that they felt, given their experience in buying art, that this particular painting by this particular artist was worth that much money. This feeling was based on other paintings by that artist and how much other people have paid for them, along with a general feeling about what the future value of that artist's paintings is going to be. Art has no intrinsic value. Meaning, you can't break it down and sell it for parts. Art is only worth money because other people are willing to pay for it. If people all of a sudden decided that Pasco's paintings were all worthless, you'd not be able to sell them at all. The price of art is 100% based on other people's perceptions."], "text_urls": [[], [], []], "score": [10, 3, 3]}}, {"q_id": "65vmxi", "category": "Repost", "title": "Why does netflix drop titles?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dgdi0jl"], "text": ["Netflix has agreements with content owners that can include specific times when content may be available. Its not always Netflix that decides. They also need a way to drive new subscribers and want to appear that they have things you have not seen yet. There is limited screen real estate on a web page and frankly viewer patience, and they want to keep your interest. Netflix is NOT a library."], "text_urls": [[]], "score": [7]}}, {"q_id": "65vssj", "category": "Repost", "title": "Why do some words have silent letters?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dgdkf90"], "text": ["\"Pneumonia\" is spelled that way because it comes from the Greek word \"pneumon\" which means \"lung\" (so \"inflammation of the lungs\"). In Greek, the \"p\" was (and still is) pronounced very clearly. But this cluster of consonants at the beginning of a word is not allowed in the phonology of English -- \"phonology\" being the rules about what sounds a language has and how they can be combined to make words. We can either insert a vowel between the consonants and say \"puh-neumonia\", or we can just not pronounce one of them -- which is what we choose to do. But we have kept the Greek spelling. Spanish-speakers, incidentally, have a similar problem with the consonant clusters \"sp-\" and \"st-\" at the beginning of a word. They find it quite difficult to say the English word \"Spanish\", and in Spanish itself words like \"to study\" become \"estudiar\", with an extra \"e\". French goes one better by then leaving off the \"s\" as well, to make \"\u00e9tudier\". Another example is a word like \"night\", with a silent \"gh\" in the middle. This is a much older English word, and originally the \"gh\" represented a sound like a rasping or gurgling noise in the back of the mouth. The German language still has this sound (and spells it \"ch\" as in the German for \"night\", \"Nacht\"), but English doesn't any more. However, we haven't bothered to update the spelling."], "text_urls": [[]], "score": [21]}}, {"q_id": "65w83z", "category": "Repost", "title": "Why are the planets all on the same plane?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dgdmkr9"], "text": ["Because the solar system is spinning. Spinning things become flat. Like pizza dough when they throw it in the air."], "text_urls": [[]], "score": [4]}}, {"q_id": "65yhqi", "category": "Repost", "title": "Why is it easier to carry a 50kg human than a 50kg dumbbell?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dge5rs3"], "text": ["There are two parts to this problem. First, the human is larger, so you have more even weight distribution. You also generally carry a human differently from how you carry weights. Second, the human moves and shifts center of mass, which may make it harder to carry a person. The combination of these factors causes the weight carrying experience to be different. Different people may perceive one to be easier than the other or for them to be the same."], "text_urls": [[]], "score": [6]}}, {"q_id": "660k65", "category": "Repost", "title": "What is special relativity, and what does it mean for how we understand the Universe?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dgeq4pa", "dgerapr"], "text": ["Do you realize that entire college degrees are spent understanding this topic and its applications?", "From Maxwell's equations to the Michelson-Morley experiment, the universe seemed to be telling us the speed of light was invariant. While scientists of the time saw this as a failure of the equations and experiments, Einstein recognized it as a confirmation of a fundamental truth of the universe. He accepted the fact that the invariant speed of the universe is defined as a constant c. From this postulate alone, Special Relativity is nearly the entire reformulation of physics to satisfy this postulate. We normally think of time as a parameter and distance as an observation: the position of an object as it moves through space is measured against time. x(t) represents the object's x coordinate at time t. And even then we could have recognized that space doesn't have a very meaningful intuition: depending on the reference frame used, your coordinates could map an object traversing a line or a parabolic path. This made movement a relationship between an object and a rigid body, not really between a natural set of spatial coordinates. Anyways... Depending on your frame of reference, a photon would travel a different path which requires an adjustment in the values of d and t to guarantee the velocity of light remains c. No longer is time simply a parameter, but is now also an observation\u200b dependent on the frame of reference used, similar to the previous example used of space. So now we create a new coordinate system that integrates both space and time as a transformation via reference frame to model reality instead of just modeling space."], "text_urls": [[], []], "score": [3, 3]}}, {"q_id": "660rpg", "category": "Repost", "title": "What is encryption?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dgesgyp", "dgeq9ak", "dgf6szm", "dgesirr"], "text": ["First off, this isn't mine, source at the bottom. Secondly, imagine that the lockbox is an algorithm. Alice wants to send a private message to Bob, and the only easy way they have to communicate is via postal mail. Unfortunately, Alice is pretty sure that the postman is reading the mail she sends. That makes Alice sad, so she decides to find a way to send messages to Bob without anyone else being able to read them. **Symmetric-Key Encryption** Alice decides to put the message inside a lockbox, then mail the box to Bob. She buys a lockbox and two identical keys to open it. But then she realizes she can\u2019t send the key to open the box to Bob via mail, as the mailman might open that package and take a copy of the key. Instead, Alice arranges to meet Bob at a nearby bar to give him one of the keys. It\u2019s inconvenient, but she only has to do it once. After Alice gets home she uses her key to lock her message into the box. Then she sends the lockbox to Bob. The mailman could look at the outside, or even throw the box away so Bob doesn\u2019t get the message \u2013 but there\u2019s no way he can read the message, as he has no way of opening the lockbox. Bob can use his identical key to unlock the lockbox and read the message. This works well, and now that Alice and Bob have identical keys Bob can use the same method to securely reply. Meeting at a bar to exchange keys is inconvenient, though. It gets even more inconvenient when Alice and Bob are on opposite sides of an ocean. **Public-Key Encryption** This time, Alice and Bob don\u2019t ever need to meet. First Bob buys a padlock and matching key. Then Bob mails the (unlocked) padlock to Alice, keeping the key safe. Alice buys a simple lockbox that closes with a padlock, and puts her message in it. Then she locks it with Bob\u2019s padlock, and mails it to Bob. She knows that the mailman can\u2019t read the message, as he has no way of opening the padlock. When Bob receives the lockbox he can open it with his key, and read the message. This only works to send messages in one direction, but Alice could buy a blue padlock and key and mail the padlock to Bob so that he can reply. Or, instead of sending a message in the padlock-secured lockbox, Alice could send Bob one of a pair of identical keys. Then Alice and Bob can send messages back and forth in their symmetric-key lockbox, as they did in the first example. This is how real world public-key encryption is often done. Bob generates a key pair, consisting of his public key (red padlock) and private key (red key). Bob then publishes his public key, and Alice fetches it (Bob mails his padlock to Alice). Alice then generates a temporary symmetric key (the pair of orange keys) and uses Bob\u2019s public key (red padlock) to securely send it to Bob. Bob then uses his private key (red key) to unlock his copy of the symmetric key (orange key). Bob and Alice can then use those symmetric keys to securely send messages back and forth. Each time you click on an SSL link or connect to your mailserver this story plays out. Your browser or mail client plays the part of Alice and the server you\u2019re connecting to plays Bob [source]( URL_0 )", "Complex math done to scramble computer information. The only way to decode it is with a special secret password (that you give to only special people you want to see the info) that would takes hundreds of years to guess even with the fastest computers. You cant see the computer info without the special password.", "Shortest possible answer: Using some sort of \"key\" to scramble a message so that it is unreadable to anyone without knowledge of the key. Simple +1 cipher. You send me the message \"Hello\". You use a +1 key, meaning A becomes B. B becomes C. C becomes D. etc. H=I E=F L=M L=M O=P. The message \"IFMMP\" is useless to anyone who doesn't know how to unscramble it. Obviously, +1 would be way too easy to figure out. That's why effective encryption uses a very complex math process and key. Now that most information is \"digital\" (can be represented on a computer with numerical values) complex math works very well for scrambling the data.", "Imagine I have a message I want to send, but it's not something I want everybody to read. I can send it \"in code\" so it seems like gibberish to anyone else. That's basically what encryption is. I could for instance just move every letter up one space in the alphabet, so A becomes B, B becomes C, and so on. So the message \"I like pineapple on my pizza\" becomes \"J mjlf qjofbqqmf po nz qjaab\". Not making much sense, it it? But if you *know* what I did, you can just reverse it and read the message. So I make sure I only tell the people I want to be able to read that message, and I won't have to worry about anyone else reading it. In this case it's \"symmetric encryption\", because anyone who knows how the message was encrypted can also decrypt it. There's another form of encryption called \"asymmetric encryption\", which is essentially the same, except you need to use one specific way to encrypt your message, and then you can only use a *different* method to decrypt it again. You could also compare it a bit like sending your message in a lockbox. In asymmetric encryption, you give out padlocks and keys to everyone who asks for them, but those keys can only *lock* the padlocks. Only a special key can unlock it, and you're the only one with that key. In symmetric encryption you have to be very careful who you give the keys to, because anyone with a key can open any lockbox sent to or from you. Now, in computer terms, this is quite common, for instance in web traffic. You've probably heard of SSL at some point. SSL uses asymmetric encryption - so you connect to a server (which is really just the computer you're talking to) and it gives you a *public key* (the one that can only lock the box). You encrypt your messages with the public key, and because only the server you're talking to has the private key, you can be sure that nobody listening in on what you're sending can read what you send. The server does the same thing the other way around - you give the server *your* public key, which the server then uses to encrypt messages sent back to you, so only you can read them."], "text_urls": [["https://wordtothewise.com/2014/09/cryptography-alice-bob/"], [], [], []], "score": [23, 5, 4, 3]}}, {"q_id": "669tic", "category": "Repost", "title": "Why do we have to turn off our cellphones during flights?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dggqaxn", "dggsexy"], "text": ["Because takeoff and landing are by far the most dangerous parts of any flight and are therefore the bits where you most need to be listening to the flight crew in case of emergency and not distracted by your phone. If they were actually dangerous to the aircraft, they wouldn't let you have them at all.", "Air flight control and commercial ISP's run on different frequencies, so no. There is no interference. But its the better safe than sorry principle. There are no guarantees that all wireless devices are up to regulation standard."], "text_urls": [[], []], "score": [9, 3]}}, {"q_id": "66cj87", "category": "Repost", "title": "What is cultural appropriation and why is it a bad thing?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dghe4hg", "dghfdwp"], "text": ["It's basically when a majority group latches onto the trends started by a minority group. It's a pretty loaded term, and often taken to extremes to mean that one idea or custom belongs to that group and no one else can have it, when in a society with free trade and exchange of ideas, it will be inevitable. As with many things, the context of why someone is using those cultural items matters more than them just simply using them. If Youre dressing in blackface, that's bad. If you like native americans and want to own a dream catcher, nothing wrong with that.", "Simplest terms. Do you share the culture of the one you are representing it? Are you attending a cultural event that requires this garb? Do you understand the cultural significance of this garb, and are you wearing it appropriately? This is not an issue of opinion. Appropriation of culture is when one individual attempts to use a culture as a fashion statement, and not for it's intended use. Let me add on to this using examples: A white man has a Native American dream catcher in their car as a mirror hang: appropriation A white man has a Native American dream catcher in a window or door way: not appropriation. A company sells kimono's as a Halloween costume: can you guess? It shouldn't be a guess because it's not a costume. Anyone can partake in any culture. That's not appropriation, that's appreciation. It's when someone decides it's use outside of the cultural norm."], "text_urls": [[], []], "score": [7, 3]}}, {"q_id": "66cnrt", "category": "Repost", "title": "How can ~90% of the web be on the dark/deep web when the majority of the users on the surface web don't even know what it is?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dghkl42", "dgheza7", "dghewbf", "dghtih8", "dghukoe", "dghevz5", "dghx1b5", "dghsxko", "dghf4c6", "dgi00ro", "dgi2oog", "dgi3e17", "dghzxzj", "dgi37b1", "dgi50z8"], "text": ["This is what happens when the mainstream media and its useful idiots make shit up, publish it, only to have it gobbled up, misinterpreted, and regurgitated by other useful idiots. The surface web, deep web, and dark web are all manufactured concepts that are almost entirely meaningless to any computer academic. Summed up briefly, they can be roughly defined as follows: Surface web: The surface web consists of web pages that are accessible or discoverable through search engines. Deep web: The deep web consists of content that is not accessible or discoverable through search engines, often requiring extensive navigation or even authentication. Most \"deep web\" content is obvious, such as password-protected services; for example, the contents of your GMail account will not be found on an anonymously accessible search engine. Dark web / Dark net: The dark web consists of content that is accessible only through the use of special software, most notably Tor, I2P, and Freenet. The problem: It's often repeated that 90% of web content is found on the deep web or dark web. However, a \"web page\" is entirely impossible to quantify, it's not a metric in any sane sense. Accordingly, it's impossible to evaluate objectively. The static web page of the 1990s and early 2000s is gone, now everything is dynamic. To make matters worse, most \"deep web\" content isn't actually deep at all, it's expressly excluded from search indexing at the website maintainer's request because it's not search worthy. However, this alone does not mean that it is not indirectly accessible through a search engine by way of another resource that incorporates it. To make matters worse, how big is a piece of \"web content\"? Are the petabytes of Youtube videos considered to be part of the surface web? It would have been more appropriate to say that there is a great deal more content on the internet than is available through most search engines; this maintains the largely subjective and highly imprecise and non-scientific matter of trying to quantify and classify the internet.", "It's important to understand that the **deep web** should not be confused with the **dark net**. The **deep web** is simply composed of all the web pages on the Internet not typically indexed by search engines like Google. This includes things like password-protected pages, dynamic pages, or encrypted networks. You visit these pages all the time, usually through means of starting from a page found on the surface web and navigating further through the website. What you're likely thinking of is the **dark net**, which is a subset of the deep web accessible only through special means, the most well-known of which is likely the TOR network. It is here that you're more likely (but not always) to find \"shady\" transactions and media content. So, to answer your question, most people actually know *what* the deep web is but simply don't know *it's called.*", "The majority of the internet is on the \"deep web\" because it is simply not indexed. This is things like user profiles on private web sites, all pages behind paywalls, and so on. Basically anything that requires you to log in, since most of those pages won't be indexed. The \"dark web\" is a very small part of the internet that also happens to be not indexed (so it's part of the deep web).", "Ok, the deep web isn't the dark net. How large a portion of the Internet is the dark net? Also the claim that most of the Internet is porn and most people using the Internet are watching porn (which I've seen claimed plenty of times), how accurate is that?", "Surface web/clearnet: google and anything you can find by using search engines. This accounts for the majority of sites and content (youtube, tv shows, pictures, ect). Deep web: Places you can't get to using a search engine. These include everything from email to databases to online libraries. For example, I can't access my Uni's online records or ebook library without a special login. Dark web: Refers to content accessible only through a tor browser in order to provide security and anonymity. An example of a dark web site is: URL_1 This is a mirror of an informative site ( URL_0 ), if you were to click on it in firefox, you'd get an error message because the address links to a 'darknet' page.", "The deep Web is simply stuff that is Web hosted but not publically available through url links. So, for a super simplified example companies use intranets all the time for document and data storage. My lab, for example, has tens of terabytes of data from the last 2 years available for our collaborators to access. That's more data than I have probably downloaded personally in the last 20 years of using the Web. But it's not publically archived or accessible, so is classed as deep web.", "well % of something does not mean % of the people who see it. my apple is 95% white, but the vast majority of people seeing it only saw the red part. theres also the black seeds, but thats the bad part and we dont really go there because thats a bit more taboo/illegal. you definitely cant see the seeds by just looking at the skin though", "When that stat was developed, a healthy portion of the 90% of the data was the [NOAA's climate database]( URL_0 ) and several other large, public data sets. Which search engines pointed to but didn't index the data stored there.", "The deep web is just anything that is not indexed by a search engine. If you have web-based email, every single part of that is \"deep.\" If you've gone to a site like amazon and bought something, the page with the purchase information is deep. As is any page that has content change based on if you are logged in. Dynamically generated pages like these far exceed the number of static web pages you could normally find, and so they make up the majority of the web. Even though a lot of them only exist temporarily.", "What are some of the \"Must see\" or must visit sites on TOR? I've had an onion browser on my iPhone for a long time but I hardly ever use it. It's a paid for one so it's updated regularly.", "ELI5 how do people access the dark web? Do they need a certain computer? Router? Edit: seems I only need the URL to a dark site, hook ya boy up! Unless it's illegal, then hook a friend of mine up!", "My website is part of the deep web, because I told robots to stay away. I use it for testing, and I don't want it indexed.", "It's like when you live in a big city and decide to shop at Walmart and target for everything when there are hundreds of smaller businesses you might have never heard of that you could go get all that stuff from instead.", "There's no correlation. The underlying layers are like outdated infrastructure that nobody uses. The criminal element we're all enchanted with is a small portion of that. Imagine subway tunnels being successively built on top of each other due to unstable ground, rising water levels, or whatever. Once you've built the 4th tunnel, 75% of \"the subway system\" is unused. It still exists, and you might even have a few people in scuba gear doing some shady shit down there.", "The Deep web is mostly just personal data and databases and stuff. And the darknet is a small part of the deep web. Sometimes, people separate the terms. The point is... Amazon, Google, Walmart, all those sites have lots of data. They have their own internal systems for managing data. And no one gets to browse this stuff, except for them. Now, granted, each company individually is not that much, but all of the companies together have a lot of data! That's the deep web. The non-indexable stuff. The private stuff. The dark web is TOR sites and doesn't take up that much storage. Compared, the deep web is huge and includes *all* non-public network-accessed pages. Some consider deep web to include darknet sites, and others don't. Really just arguing semantics at that point IMO."], "text_urls": [[], [], [], [], ["deepdotweb.com", "http://deepdot35wvmeyd5.onion"], [], [], ["https://www.ncdc.noaa.gov/cdo-web/"], [], [], [], [], [], [], []], "score": [6702, 3287, 164, 59, 38, 30, 16, 14, 9, 6, 6, 3, 3, 3, 3]}}, {"q_id": "66ds5x", "category": "Repost", "title": "What prevents banks and other institutions that hold money electronically from just digitally changing the amount that they have?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dghoen9", "dghsziy", "dghucmv", "dghoin9"], "text": ["There are audit trails. Every time money is added to an account, there **must** be a corresponding removal from another account somewhere, and every step has to be recorded. If government auditors find that there was fraud committed, and money just materialized out of nowhere, someone is going to federal prison for a very long time.", "banks don't actually hold money electronically in that sense. what they have is claims on other entities. for example, if they've given lons, they hve a right to repayment. if they change the amount loaned on their books, naturally the borrower will notice and sue them. if you're thinking of the \"spare cash\" a bank has, well, it has to keep it with some other bank, right? that's usually the central bank, which generally doubles as the regulator. and if you pretend you have more money deposited with it than you do, well, that'll go about as well as you pretending you're a millionaire.", "The electronic banking record isn't a record of \"amount that they have\", but a record of how much money they owe to/from somebody. You can calculate the capital that a bank owns by subtracting the claims others have on the bank (i.e. customer deposits) from claims the bank has (i.e. loans, funds held with other institutions, bonds), but it's a secondary metric that depends on the actual claims that each can be verified separately. Changing the record doesn't change how much money you owe, it just means that you have a wrong record - which will be (generally) noticed by the other party. I.e. if a bank would set your account balance to zero and refuse to correct it, you'd go to a (small claims?) court and get your money anyway. It's a bit misleading to think of electronic banking as electronic cash (this analogy might be more suitable for Bitcoin), they're really electronic I-owe-you's exchanged all around.", "They are audited by a 3rd party. If they tried to make something appear from nowhere, there would be a discrepancy in the records. Penalties could range from huge fines to criminal charges."], "text_urls": [[], [], [], []], "score": [39, 10, 5, 4]}}, {"q_id": "66fv4q", "category": "Repost", "title": "If laws over marijuana use is such a concern-how can people (Willie Nelson, Woody Harrelson, Seth Rogen, etc) flaunt such a lifestyle seemingly without consequence?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dgi6v05", "dgi6v1l", "dgi6s5q"], "text": ["Possession is what is illegal. Snoop was arrested here in Texas after they pulled over his tour bus.", "They have enough money that any punishment the court could possibly levy against them can be bargained away. With money, either given directly to the court system or donated to law enforcement.", "Being caught with marijuana is only an issue for people that can't afford to get caught with marijuana. Edit: in states where it's still an issue."], "text_urls": [[], [], []], "score": [4, 4, 3]}}, {"q_id": "66ha0v", "category": "Repost", "title": "Why can't video game graphics be as realistic as movie CGI or the in-game cutscenes?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dgifjfl", "dgigflt", "dgifcan", "dgifhex", "dgii7oa", "dgijfpv", "dgihbda"], "text": ["Think about it - the difference between a cut scene, and actual gameplay. The main difference is that in a cut scene, it is a video. It may looks 3D but it in fact is not, it is a 2D flat video image which depicts a 3D scene. In game, however, everything has to be rendered in real time in 3D. It requires processing power and memory.", "The question you're asking is about a process called rendering. Rendering is the grunt work that the computer does that turns code and 2d images into a simulated 3d scene. With a cut scene, or CGI they can make it incredibly complex, something that takes hours and hours to render using a very powerful computer. Then take that movie clip and show it to you. This is known as pre-rendering. It allows for very good, very complex computer generated graphics. Video games can't work that way because the scene has dynamic elements to it. Where your character is located, and what direction they are looking in changes the scene being displayed. You can't pre-render this kind of thing because that perspective information is required in advance. So with a video game, the game needs to do the rendering on the fly, as you are playing. That means they don't get to use a supercomputer for several hours to calculate the movement of individual strands of hair on someone's head. So they take shortcuts that are \"good enough\" but still noticeable. And that's why the graphics are not as good.", "CGI is rendered on very high end hardware and usually takes hours to render. In game graphics need to be rendered 30+ times a second", "The amount of time taken to render those scenes is massive. So if you have a movie that's two hours of CGI kickassery, that's probably close to a year of hard work from multiple artists. Taking that and applying it to a video game, making every inch of an environment, the characters, and anything else look that good would take even longer. Especially since in a movie, you aren't walking into every nook and cranny searching for things.", "Former game developer here, The difference is in the capabilities of pre-rendering and real-time rendering. A modern console can render ~400k polygons per single frame - at 60 frames per second. A pre-render in a cutscene or in a movie is going to be in the hundreds of millions per frame. Further, the equations and algorithms we use to light and color each pixel are very different. pre-render doesn't care about cost so much as correctness, because they can always throw more hardware at the problem. In video games, we fake it as much as possible. A pre-render is far more capable in their visual effects than a game engine. The two simply do not compare and they never will. As real-time rendering becomes more capable, which is strictly a hardware problem, so too will pre-rendering.", "If you'd like an extreme--and extremely stupid--example, I happen to have one: * URL_0 The original of this image was made from two 9999 x 6179 renders in DAZ Studio. It took just about 24 hours to compute each one to produce a red-blue 3D image. It's true that the processor was an old Intel Core 2 Quad, but it still ran GTA V at mediocre settings and 1280 x 768 resolution above 30 frames per second. (And yeah, the background is shite because I hand-drew it on a windy mountaintop.) So there you go: 30 frames per second versus one frame per *day*, helped along by various dumb decisions on my own part. Professionals don't make the mistakes I do and don't deal with obsolete hardware, but it still illustrates the disparity between a native render and a a game render: the game has to be (30 x 60 x 60 x 24 x 2) 86,400 times faster to be playable!", "There are several reasons. Note that on this list number 2 and 3 apply less to in game cutscenes, even when rendered in real time. Two in particular is why you get stuff like Shepard in Mass Effect pulling out a pistol when you've got an assault rifle. 1) Processing power. This is a big one, doing it in real time on a home PC affords a lot less power than a week on a computing farm. 2) Games are dynamic - you have to have animations which work for any situation. By contrast, in a movie you can specifically do every single animation. Similarly, if you have a character in a game with equipment that you can change, the number of different permutations means each animation will look better or worse for each weapon. 3) Manual tweaks. Sometimes stuff looks a little weird randomly. Maybe a model will intersect another, maybe it will be perfectly accurate but look weird (for instance, lens flair is used in games / movies, but isn't actually realistic). For whatever reason, when this comes up in a movie, they can manually tweak that specific frame / section. Not so in video games."], "text_urls": [[], [], [], [], [], ["http://imgur.com/gallery/hN9hL"], []], "score": [8, 4, 3, 3, 3, 3, 3]}}, {"q_id": "66noxx", "category": "Repost", "title": "What is a fascist?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dgjye5k", "dgjxs4j", "dgjwwwa", "dgk4rny", "dgjxg1i", "dgjx9uy", "dgjydqx", "dgjx8qi"], "text": ["Fascism doesn't have a universal definition that can fit every iteration. Due to its roots in extreme nationalism, the \"flavor\" of a fascist ideology will vary heavily based on its country of origin. Hitler's National Socialism was not the same as Mussolini's Fascism, or Franco's Falange. Any homegrown American fascism will not be the same as Nazism. But by and large, fascist ideologies tend to be extremely nationalist, extremely statist, and extremely racist. However, the fascist ideologies tend to share a number of common or similar factors. [Umberto Eco's 1995 essay \"Ur-Fascism\" is extremely useful in this regard]( URL_0 ). Eco (who lived his childhood during Mussolini's rule of Italy) pinpointed 14 common factors that fascist ideologies largely share. I will attempt to briefly summarize each. 1. **Cult of Tradition**. Fascists will attempt to combine their associate their new ideology with much older traditions and traditional imagery. For example, in *Triumph of the Will*, there are many shots of centuries-old churches, cathedrals, and other medieval architecture, frequently with huge Nazi flags flying over them; the objective being to associate Nazism and Nazi rule with the stability and longevity of these buildings. This also played into Nazi architecture (an imitation of classical Greek and Rome) and symbolism (Nazis heavily, heavily cribbed Roman imagery) 2. **Rejection of Modernism**. Fascists will reject modern culture, political values, and art. They will frequently attempt to portray modern, post-Enlightenment values and art as \"degenerate\" in some way. For example, the Nazis suppressed \"degenerate\" art by Modernist artists, decrying it as \"Cultural Bolshevism\" (an attempt by the Jews to undermine German culture from within) and either throwing said dissidents into concentration camps or expelling them from the country. They also encouraged their own vision of \"traditional\" art. 3. **Cult of Action for Action's Sake**. Thinking and intellectualism is weak, degenerate, and unmanly. Fascists persecute intellectuals because intellectuals will be their fiercest and most dangerous political opponents. Thus, they must be discredited, so their professions and habits themselves must be portrayed as \"un-manly\", \"degenerate\", or \"cultural betrayal\". Proper INSERTCULTURE men shouldn't stop to think like a Jew or a woman, they should throw themselves against the Enemy in defense of the Nation without hesitation. 4. **Disagreement is Treason**. Fascist dogma is irrational and largely a pack of lies, and will not survive dedicated analytical criticism. Building upon #3, intellectuals must be persecuted and dissent suppressed. 5. **Fear of Difference**. Fascists stoke ethnic, religious, national, and/or racial divisions to channel the energy of their populations. They must fear the intervention and machinations of a great enemy or enemies. Arbitrary lines will be drawn to divide \"True Nationians\" from \"Others\". For the Nazis, this was the International Jewish Conspiracy against Germany. 6. **Appeal to the frustrated Middle Class**. Fascism's biggest support tends to come from a frustrated middle class that feels they are under intense pressure. This middle class will be resentful of the wealthy and privileged upper class far above them and fearful of the restless lower class below. Fascist takeovers are typically precipitated by major economic stress and the spectre of a socialist or communist revolution. 7. **Ethno-Nationalist Identity** and **Obsession With A Plot**. Fascists will seek to unite their key demographics through extreme ethno-nationalism. They will define what a \"Tue Nationian\" is via arbitrary lines and set that demographic against the Other. The Nazis used the Aryan ideal and anti-Jewish persecution to determine what a \"True German\" was. Additionally, fascists must convince their \"True Nationians\" that they are constantly under threat, under siege, by their enemies. They will do this by drumming up major xenophobic sentiments and targeting minority races and ethnicities. 8. **Paradoxical Opposing Strength**. Fascists must convince their people that their enemies are simultaneously so overwhelmingly strong that they humiliate the nation, but they also weak enough to be overcome by the united effort of the nation and people. Because they must encourage this narrative and in fascism dogma dominates policy, fascist nations frequently cannot objectively estimate the true strength of their enemies and will lose wars as a result. 9. **Life is Permanent Warfare**. Fascists are frequently extreme Social Darwinists. Struggle always improves oneself. The great enemy can only be overcome through struggle. The strong must constantly compete to determine the strongest. In reality, this creates a mess of petty, unstable politics as fascist officials backstab each other for advancement. Hitler's Nazi Party and German armed forces were an absolute mess of cross-jurisdictional conflicts. 10. **Contempt for the Weak**. Fascism is extremely hierarchical, and the masses from whom the fascists have seized power and mandate by force (it must always be by force in a democracy) must be kept under heel. Those who fail in the permanent struggle of life are weak and not worthy of attention. Fascists must despise their subordinates as weaker specimens of mankind. It is a popular elitism that plays into the fascist narratives of Social Darwinism and Ethno-Nationalist Identity. 11. **Cult of Heroic Death**. There is no greater virtue than to die in service of the Nation. Men are encouraged to seek a heroic death on the battlefield above all things. The ideal fascist hero *craves* his heroic death and will not hesitate to throw himself (or his subordinates) into combat against the enemies. This is a critical step in indoctrinating millions of young men into unquestioning military service. 12. **Machismo**. Women are held in contempt and confined to strict gender roles. Their primary purpose is to tend to the home and breed more soldiers. Hyper-masculine virtues are encouraged, and any lifestyle that runs counter (such as homosexuality) to hyper-masculinity is decried as \"degenerate\". 13. **Selective Populism**. The People is a monolithic entity. The People must be willing to sacrifice their individual rights and freedoms and fall in rank to support the State and the Leader. The Leader represents the voice and common will of the People. Fascists will drum up populist imagery and rhetoric in order to seize power, but the population is expected to fall in line behind them once they are in power. For example (and combining with #10), near the end of the war, when the Soviets battled for Berlin, Hitler expressed ultimate contempt for his own people and claimed that the German people \"deserved\" to be annihilated by the Soviets - they had voted him into power (they didn't), supported him as the embodiment of their Common Will (out of fear), struggled against their enemies, failed, and thus deserved to pay the price of extermination. 14. **Newspeak**. Fascists must alter language itself to suppress criticism, dissidence, and \"degenerate\" art. They will frequently use loaded phrases to communicate meaning or encourage certain concepts. Frequently, any communicative media that is not run by the State is suppressed, because the only truth comes from the State, the Party, and the Leader. To go on a slight tangent here at the end, the popular film *Fight Club* is a really great portrayal of the rise of a fictional fascist ideology, and it hits many of these exact points. And yes, Project Mayhem is *fascist*, not anarchist.", "ITT: People defining a complex political term in terms of other complex political terms. A fascist is someone who: - believes their country is the best - convinces the people he has a plan or making his country the best - wants to elimimate other voices, opinions, and plans for making the country the best - wants to not be held accountable by the country's rules or constitution as he follows through on his plan - is willing to use force to keep the people in check as he follows through on his plan", "Fascism specifically refers to authoritarian rule via nationalism. It comes from Mussolini's party pre-WWII. It's only associated with the Nazis because Germany was the more prominent Axis power.", "Fascism is actually an Italian word, *fascismo*, which comes from the harmless word *fascia*, which is simply any device used to keep together or bundle things, like a buckle and strap. Fascismo is called that because it's the idea of keeping everything and everyone together under one \"fascia\". The meaning of the word is actually quite literal. In fact, it should probably be called fascismo in English as well, since the root of the word is 100% Italian, just like solo, arpeggio, scale, opera, orchestra, etc. Fascism is simply the word Mussolini used to coin his type of rule. A fascia is basically a fastener to bundle things together, so if we were to translate the word *fascismo*, it would be something like \"fastenerism\".", "While there are specific meanings given in other answers, it's important to note that these days, \"Fascist\" is little more than a grab-bag political insult to mean basically \"anyone who doesn't agree with me\". Because of its association with Hitler, 'fascist' is the strongest pejorative used by both Left and Right to discredit/attack anyone they don't like. So be careful when you read that this person called this other person a 'fascist'.", "In technical terms, a person subscribing to the political ideology of fascism: a socially-far-right, economically- and nationalist-authoritarian movement with a strong tendency to economic protectionism, militarism, and imperialism. Fascism tends to promote a totalitarian military government, and reject democracy. In (inaccurate and) hyperbolic rhetoric, anyone of an apparently authoritarian bent whom the speaker dislikes.", "Under Fascism there's a strong emphasis on political, social and cultural unity. The [original symbol of Fascism] ( URL_0 ) in Italy is a tight bundle of sticks, symbolising strength through unity: one stick is weak, a bundle is strong if tightly bound. So anything that threatens that unity is a threat to the state and must be suppressed, even if that's just a dissenting opinion. It's important to understand that Fascism alone is not a system of government or an economic model: it appears alongside other systems. For example, Stalinism = communism that had fascist elements to enforce it, while National Socialsim (Nazism) was a warped, belligerent form of Socialism that favoured large private industries, with Fascism to ensure national unity behind the state's goals.", "A person supporting a system of government based around extreme authoritarianism, nationalism and optionally a \"third position\" in economics against both capitalism and communism, or a member of a party that supports that system."], "text_urls": [["http://www.pegc.us/archive/Articles/eco_ur-fascism.pdf"], [], [], [], [], [], ["https://en.wikipedia.org/wiki/Fascist_symbolism"], []], "score": [190, 135, 37, 12, 10, 7, 4, 3]}}, {"q_id": "66onrk", "category": "Repost", "title": "When and why did 18 years old become considered \"adult age\" worldwide?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dgk2l0z"], "text": ["Eighteen is, on average, the age when people stop getting any taller, so many societies adopted that age as the age of adulthood."], "text_urls": [[]], "score": [7]}}, {"q_id": "66pr62", "category": "Repost", "title": "what is morning breath and why do we have it?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dgkaz6o"], "text": ["Your mouth is filled with hundreds of millions of bacteria. Generally when you sleep, your mouth is open, which dries it out. Your salivary glands are also much less active when you sleep. This allows those bacteria to hang around and produce nasty-smelling compounds that are not swept away by your saliva and swallowed as they are when you're awake. If you want to reduce the stench of your morning breath, keep a glass of water next to your bed and have a few sips every time you wake up."], "text_urls": [[]], "score": [8]}}, {"q_id": "66pxej", "category": "Repost", "title": "How can baby animals start walking basically immediately after their birth, but humans can't?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dgkc06j", "dgkc2rt"], "text": ["Some species of animals are *precocial* which means they are relatively mature and mobile from the moment they are born (or hatched.) Humans are *altricial* which means our young are born pretty much helpless. But we are far from the only altricial species! Rabbits are born blind and hairless, for instance, which is why rabbits give birth underground. Most other primates are altricial as well. It has to do with evolution and habitat. For instance, cetaceans (whales and dolphins) are precocial, because they live in the sea, and their babies would drown if they couldn't swim from birth.", "Humans are not able to survive alone. They are not very mature at birth, because their huge brain needs to grow and if their head was any bigger it wouldn't fit through their mother's pelvis. It takes months for it to grow enough that they can crawl, and years before then can walk and run adroitly. Smaller brains are simpler, less flexible, and fit into a smaller head, even though they can still control a large body."], "text_urls": [[], []], "score": [7, 3]}}, {"q_id": "66t6p8", "category": "Repost", "title": "What is Net Neutrality?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dgl2x7a"], "text": ["its basically forcing internet service provider companies to treat all internet sites and services as equals instead of picking and choosing or setting up impossible hurdles for whom they want , either for money or other stuff. like imagine you had watchflicks and could potentially make a lot of money but the ISP couldnt handle the traffic or doesnt want to invest into the infrastrucuture/ R & D and instead they make it so your customers can only watch raw potato quality video after they buffer for 3 days and 2 nights in the bahamas, courtesy of you."], "text_urls": [[]], "score": [5]}}, {"q_id": "66t71q", "category": "Repost", "title": "why school busses don't have seat belts?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dgl4usx"], "text": ["The primary purpose of a seatbelt is to prevent ejection through the windshield. This is a smaller risk in a bus because of the seat configuration and because of the mass of the vehicle. If a bus collides with a car the result will be that the bus pretty much just plows right through it because it weighs 10 times as much."], "text_urls": [[]], "score": [8]}}, {"q_id": "66u9pa", "category": "Repost", "title": "\"Beer before liquor, never been sicker. Liquor before beer, you're in the clear\"", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dglco2x", "dgldotf"], "text": ["It is a myth. It is based on the fact that if you drink hard liquor later in an evening of partying where you have already gotten drunk off of beer you will be more likely to drink too much and become too drunk, thus making you have a worse hangover and possibly making you sick during the night. But if you drink hard liquor first to get drunk then drink beer through the night you will tend to get less drunk due to beer having a lower amount of alcohol in it.", "The mantra addresses the concept of \"tapering off\". Hit the hard stuff early and transition to the weak. It applies to most substances. Do a couple lines and then bump as necccesary. Dab and then smoke to maintenance the high. Start with a full tab and take a half if you aren't peaking. Remember: Alcohol is alcohol and drugs are drugs. Be smart about things and you'll always be \"in the clear\"."], "text_urls": [[], []], "score": [13, 3]}}, {"q_id": "66uo58", "category": "Repost", "title": "Why do rockets start vertically and not horizontally likes planes to reduce the needed thrust for the takeoff?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dglfpgg"], "text": ["It takes less fuel to launch vertically, get higher in the atmosphere where the air is thinner (less resistance to work against), and curve gradually to increase orbital velocity. The goal is to get out of as much of the thick lower atmosphere as possible using as little fuel as they can"], "text_urls": [[]], "score": [14]}}, {"q_id": "66vyp3", "category": "Repost", "title": "What are G\u00f6del's Incompleteness Theorems?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dglp0t0", "dgluxmh"], "text": ["Maths is based on things called axioms. These are rules that we accept before we can do maths. For example, 10 + 5 = 5 + 10 the order in which we add numbers doesn't matter. Axioms are just rules we take to be true and using these rules we try and find out other things and prove whether something is true or false. Obviously in maths, in particular arithmetic (adding, subtracting ...), we have many axioms and those axioms form a system. A complete system is one where you can prove whether something within the system is either true or false. A consistent system is one where you will never get a contradiction i.e. something that can be proven both true and false. Godel's theorem states that you can never have both of these in an axiomatic system. Meaning you will either end up with a contradiction or there will be certain things that cannot be proved true or false no matter how hard you try", "Mathematicians like to have systems for answering questions. You probably learned some of these systems in school. Long division is just a system for answering questions like \"What is 156/12?\" But mathematicians don't like having a different system for each kind of question. They want one system that can answer any kind of question. The first incompleteness theorem proved that this is impossible. No matter how cool your system is, there will always be some questions it can't answer. The second incompleteness theorem gives an example of an important question no system can answer. Specifically, no system can answer the question of whether they will ever contradict themselves."], "text_urls": [[], []], "score": [8, 3]}}, {"q_id": "66w3yj", "category": "Repost", "title": "How is it possible for a \"master key\" to exist?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dglr6ta"], "text": ["A cylinder or 'Yale' lock has a rotating cylinder inside a fixed lock body. There are vertical holes in the lock body and cylinder, with pins in them, with each pin being cut into two pieces. The key lifts the pins by just the right amount so the cut lines up with the join between cylinder and body so the cylinder can rotate. If the wrong key is used the cuts don't line up and the pins stop the cylinder rotating. It's much easier to explain with a diagram: URL_0 To make such a lock work with a master key, each pin simply has two cuts not one. One set of cuts will be made to line up by the master key, the other set will be made to line up by different keys for each lock."], "text_urls": [["https://en.wikipedia.org/wiki/Pin_tumbler_lock#Design"]], "score": [5]}}, {"q_id": "6711se", "category": "Repost", "title": "What is a VPN and what does it do?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dgmut9y"], "text": ["The internet is similar to a postal system, everyone has an address and with that address, the post office knows how and where to send something. On the internet, this is done in the form of IP addresses, usually 4 different numbers that act as everyone's address. When you want to connect to google, your computer uses a system called DNS to find the IP address of google and send stuff back and forth between it. However, the person controlling your wifi can stop a signal to an address similarly to how a post office can stop your package from reaching other post offices if they don't want you sending something to that address. What to do then? Well, a VPN acts as a proxy in this case (it can be used for more, but this is its most common use). You want to send a letter to bob, but the post office doesn't let you send a letter to bob. So what you do is you go to your friend Joe who lives a city over and ask him to forward all your packages to him to Bob. And if bob wants to send you packages, he sends them to Joe, who sends them to you."], "text_urls": [[]], "score": [6]}}, {"q_id": "673pp1", "category": "Repost", "title": "Why does splitting an atom release so much energy?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dgnetgd"], "text": ["More specifically, nuclear reactions are not splitting just one atom. They split one atom, which succeeds at splitting more atoms, which split even more atoms. Each time those atoms split, they release a small amount of energy. Do this several billion billion times in a very short amount of time and you get a big release of energy, also known as an explosion."], "text_urls": [[]], "score": [5]}}, {"q_id": "673rc8", "category": "Repost", "title": "If you have a really long stick.", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dgneyvo", "dgni9br"], "text": ["No, the pressure moves at the speed of sound. This would be kind of entertaining because the stick, from a faster-than-light-thought-experiment standpoint, would be really curved.", "No. An imaginary perfectly rigid stick would be impossible to rotate fast enough, its 'moment of inertia' - resistance to having its spin sped up - would increase without limit as its tip got closer and closer to the speed of light. A real stick would bend."], "text_urls": [[], []], "score": [6, 3]}}, {"q_id": "673riy", "category": "Repost", "title": "Why do some body parts (e.g. breasts and penises) vary so widely in size and appearance while others (e.g. fingers and ears) stay within a relatively narrow range of size and appearance?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dgnh0uq", "dgnevdi"], "text": ["It's because breasts and penises are soft tissue while your fingers have bones in them. The bones are what ultimately dictates their size, and don't allow for as much variance across the population.", "I think it has allot to do with hormones and genetics. So fingers and ears aren't that greatly affected by hormones compared to genitals and breasts. Also there's an evolutionary aspects to the shape of our ears, feet, hands, head, nose etc... They're shaped that way through evolutionary means. For breasts and genitals they generally all do their job so shape and size isn't as important as long as it works for what it's there for (breast feeding, pro creating). It may also have to do with what we generally see and how attractive ppl find others. Generally you don't use genital appearance or breasts size as a deciding factor to find a mate. I'm no expert but this is how I look at it, not sure if it answers and if someone has a better answer, I'd love you be educated on this as well."], "text_urls": [[], []], "score": [5, 3]}}, {"q_id": "673wzj", "category": "Repost", "title": "Why is salt and pepper used to season EVERYTHING in the culinary world? Like, what makes these two things so special?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dgngm61"], "text": ["Pepper isn't *that* ubiquitous; it very much depends upon the cook and the style. Salt, on the other hand, is one of the basic flavours to which humans are sensitive, so it's hardly surprising that we like to be able to regulate the level of it in our food. It's like sweetness in that respect, only it doesn't occur naturally in as many foods, so having it as an additive is more useful. That's before we even consider what others (at the time of editing, BrokenSpectr and bashar_speaks) have noted about the body *needing* sodium and potassium, and their chlorides being among the most readily-available salts for consumption (OK, that's not exactly what they said, but I don't think inserting extra information should be a problem)."], "text_urls": [[]], "score": [5]}}, {"q_id": "674bwr", "category": "Repost", "title": "If a Nuclear war can bring Havoc to worldwide climate then why that didn't happen when nuclear tests were in full swing ?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dgnjqmw"], "text": ["Well, to be honest, a few theoretical problems relating to nuclear weapons didn't really pan out. For one, some people thought even a small nuclear test would start a chain reaction in the Uranium in the Earth's crust, effectively scorching the entire surface of the planet. Or maybe igniting the atmosphere, and leaving us like Mars. It's not precisely 'nukes' that were going to cause climate havoc. Nuclear winter isn't really nuclear, necessarily. It just means enough crap gets kicked up that it blots out the sun for a while, and long-term increases the reflective powers of the atmosphere: less radiation, cold as Fick, ice age. You could get the same effect from a series of huge volcanoes, or even a big enough/proper distribution of conventional weapons. There's actually a device that can output particulate into the atmosphere, lowering the temperature quite drastically. It's more of a weapon than a solution though. I seem to have losty thread a bit. Nuclear winter would require multiple bombs in multiple locations. That said, large scale testing (that is, the big Russian bombs) did impact the weather for relatively short periods, similar to the eruption of Mount St Helens. Edit: Oh or a really big asteroid impact. Or possibly setting all the oil wells on fire at once. Or a magma plume ignites a huge coal seam (I think this might have been the cause of one of the major extinction events but I'm not sure). Remember the dinosaurs? Anyway. The end is fucking nigh, you know?"], "text_urls": [[]], "score": [3]}}, {"q_id": "675pn5", "category": "Repost", "title": "How do we build a tolerance for spicy foods as we eat more of it?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dgnvoo7"], "text": ["As we expose ourselves to more capsaicin, the chemical responsible for the \"burning\" sensation in chili peppers, the taste buds lose sensitivity to it. It's kind of like exposing your hands to gradually hotter temperatures. Your hands will become less sensitive to heat, but there's a limit."], "text_urls": [[]], "score": [4]}}, {"q_id": "675zkd", "category": "Repost", "title": "When a person is diagnosed with a terminal illness how does a doctor figure out how much time the patient has left?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dgo45ii", "dgnyefl", "dgo11u4", "dgo124u"], "text": ["Hospice RN here. We get asked this all the time. Doctors and other medical personnel can prognosticate (make an educated guess) about how long a patient has left, but it is not an exact science. We don't usually given a exact answer; we would tend to say \"several months\" or \"several weeks\" or \"days to weeks\" or \"a few days\" or the absolute worst \"minutes to hours.\" Here are a few things that affect that educated guess: 1. How advanced the disease is. Cancer only in the lungs isn't as bad as as cancer in the lungs, bones, brain, and liver. Other diseases like COPD and heart failure are evaluated on how bad the symptoms are and how frequently they happen. When the symptoms happen all the time at rest (no physical exertion.) 2. The overall health of the person. If someone was a healthy marathon runner in their 50's diagnosed with the same terminal cancer as someone in their 80's with uncontrolled diabetes, high blood pressure, and general advanced age, guess who would live longer? The marathon runner is likely to live much longer. 3. Loss of functional status. How quickly is the patient physically declining? If someone was able to fully take care of themselves (eat, bathe, drive, pay bills) three months ago and now is bed bound and cannot perform any self care and is mentally out of it, they likely don't have long. If that same decline took two years, the patient likely has more time because rate of decline is slower. It's not an exact science and patients can surprise us. Sometimes the disease can cause sudden death - cancer patients are much more likely to throw a blood clot and die suddenly - cancer makes the blood hypercoagulable - basically more sticky. If a cancer eats into a major blood vessel or cuts off circulation to a major organ, it's lights out pretty quick. Likewise, heart failure makes the possibility of a heart attack much more likely. On the other hand, patients can live longer than expected - sometimes people's bodies are more resilient than we can quantify. tl:dr - it's not an exact science but we evaluate the overall disease progression and health status of the patient.", "By comparing their diagnosis to other, similar cases. Also, doctors rarely say \"you have six months to live\". They typically say things like \"About 50% of the time, patients with this diagnosis do not survive more than 6 months\".", "Back in the day, doctors sort of...guessed. Studies have shown their predictions were not very accurate. Nowadays, we have much more data and evidence because we track disease and outcomes overtime. Let's say you have cancer. Doctors will look at what specific type of cancer you have (for example, anaplastic astrocytoma vs glioblastoma multiforme vs low grade glioma). In some cancers they might look at what genetic subtypes there are, etc. They will also look at where that cancer has spread. For other diseased, such as cirrhosis, they might look at what residual liver function you have left which they can determine from laboratory testing. If you have a bleeding disorder or renal failure secondary to the cirrhosis, that has a poorer prognosis than not having those things. Based on that information they look for published data from studies which might show that for patients with similar cases the median survival is 2 yrs, meaning half of all patients live longer and half live less than that. They might also find that overall the survival at 5 years is less than 10%, meaning 90% of patients die within 5 yrs. Depending on the stage of the disease there might be a lot or there might be very little variability in terms of survival. So while patients might say \"doctors gave me only 2 years to live\" the doctor *probably* didn't say that but that might be what the patient comes away with anyway. It's a lot to absorb being told you're going to die and patients often like a number.", "There are also computational tools we use to give us a good estimation. For example: lab values in patients with liver failure can be used to estimate likelihood of dying in the next few months."], "text_urls": [[], [], [], []], "score": [51, 20, 6, 3]}}, {"q_id": "678ctj", "category": "Repost", "title": "What is an API in programming", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dgoflvq"], "text": ["It's a complicated word for a simple concept. It stands for Application Programming Interface, but it's barely worth remembering. It's just a promise or a contract. Like 'if you give me a number A and then a number B, I'll give you A+B'. This kind of thing is used EVERYWHERE in programming, including that exact example. The word now tends to be used to refer to a handful of Web technologies, but the premise is the same - a promise that if you give me X I'll give you Y."], "text_urls": [[]], "score": [3]}}, {"q_id": "67eagg", "category": "Repost", "title": "If swelling is the body's natural response to some injuries, why do doctors generally recommend doing things to reduce swelling? Isn't the swelling response there for a reason?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dgprz0r"], "text": ["[Recent relevant SciShow]( URL_0 ). Sometimes your body goes too far and the swelling becomes more harmful than helpful as too much blood attempts to rush into the injured area to bring resources, and as a result it gets clogged up and at the very least is no longer being helpful. Ice reduces the swelling, allowing the fresh blood to flow better - until your body sends even *more* blood to warm that area back up. So you get more of the resources your body is trying to bring you. With modern diets, medicine, and activities you're not losing much by reducing the swelling, even if you were losing some of the beneficial effects. In the mean time, swelling is often inconvenient: it hurts, it makes it hard to use that limb, and most things that reduce swelling (like ice) also help take some of the pain away."], "text_urls": [["https://www.youtube.com/watch?v=-P8Qh4MuyVc"]], "score": [6]}}, {"q_id": "67fqqu", "category": "Repost", "title": "what causes the growling noises your stomach makes when you're hungry?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dgq33ap"], "text": ["The short answer is that you are feeling/hearing fluid (swallowed saliva, digestive juices, liquids you drank recently) and small amounts of air (swallowed or produced by bacteria or chemical reactions) in your stomach and intestines being pushed around when the muscles of your digestive tract contract. These events become noticeably rumble-y when the muscle activity increases. One reason that happens is because when you're hungry, you naturally think about eating, so your nervous system tells the muscles in your digestive tract to start working since soon there might be food to digest and move through it. Being nervous can also cause muscle activity in your digestive tract to increase, so you might notice that your stomach growls more than usual during a first date or an important meeting."], "text_urls": [[]], "score": [19]}}, {"q_id": "67gme3", "category": "Repost", "title": "Why do mirrors only flip the image horizontally and not vertically as well?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dgq77cv", "dgq80u7", "dgq79fp", "dgq7f9f"], "text": ["Mirrors don't flip images, the mirror is displaying exactly what is in front of it. For example when you stand in front of the mirror you see your right arm on the right. That is because it is directly in front of that portion of the mirror. So...when you are standing in front of the mirror your head is at the top, because it is directly in front of that section of the mirror.", "I think this has come up before, but anyways; mirrors don't flip left and right, [they flip front and back]( URL_0 ).", "They don't flip anything. The orientation of the reflection is directly across from where the object is.", "Mirrors don't flip things at all. You're comparing what you see in the mirror to what you would see if you walked in front of yourself and turned around horizontally. Alternatively, if you stood on your head, the view would be reflected vertically compared to what you see in a mirror."], "text_urls": [[], ["https://www.youtube.com/watch?v=vBpxhfBlVLU"], [], []], "score": [8, 6, 5, 3]}}, {"q_id": "67k8dy", "category": "Repost", "title": "Pharmacists, why does it take 15-30 minutes to fill a prescription like pills, even when it's not busy?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dgr1kcz"], "text": ["Just because you're the only person physically there doesn't mean you're the only person getting a prescription filled. Prescriptions are transmitted directly to pharmacies from doctors offices, prescriptions are dropped off for later pick-up, and refills can be requested via certain pharmacy apps given the script used allowed for refills. A pharmacy tech will have a workload and while a person there waiting might get dropped in for more immediate filling, if you're standing there wondering why it's taking so long, you're not an emergent situation."], "text_urls": [[]], "score": [3]}}, {"q_id": "67ml9d", "category": "Repost", "title": "Where do banks keep their money? What stops them from just adding a 0 somewhere?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dgrl1o2", "dgrl4es"], "text": ["The Government or a Government Empowered Organization makes sure by Auditing the Bank. They check through the records of how the money came and went and how interest was payed out to make sure nobody accidentally or intentionally messed up the numbers.", "But clearly they don't have a bunch of physical money. If your account has 100k it's not like they have 100k sitting around. (X thousands of people's balances). It's all numbers on paper/computer (how did they keep track before computers?)"], "text_urls": [[], []], "score": [4, 3]}}, {"q_id": "67qr3o", "category": "Repost", "title": "Why can humans get Vitamin D from sunlight but not from artificial light?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dgsha73", "dgshe5s"], "text": ["The lights need to emit ultraviolet B rays in order for your body to create vitamin D. Unfortunately, too much exposure increases the risk of skin cancer, so you generally do not want to have standard lights that emit that ultraviolet light. You *can* get specially made artificial lights that emit ultraviolet B rays for people that live in areas without too much sun, but they usually have a timer on them to auto shut off after a time and a warning against too much exposure.", "You get vitamin D from ultraviolet light, and there isn't much ultraviolet light emitted by everyday light bulbs. You can use a tanning bed or other source of artificial UV, though."], "text_urls": [[], []], "score": [8, 3]}}, {"q_id": "67s1jm", "category": "Repost", "title": "Why do women's menstrual cycles sync up after a while when living together?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dgsrszj"], "text": ["They don't, it's a popular misinform. Am a woman, get periods and have had many female roommates over the years"], "text_urls": [[]], "score": [5]}}, {"q_id": "67ueww", "category": "Repost", "title": "64 and 32 bit, and the differences?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dgtc2k4"], "text": ["32 or 64 Bit describes the length of numbers in binary the processor calculates with, which means there's a maximum number the processor can handle. For 32 Bit that is 2^32 - 1 so about 4 billion. 64 bit means bigger numbers, bigger calculations. 64 Bit can handle 2^64 - 1, which is 9,223,372,036,854,775,807. But one of the bigger reasons to use 64 Bit is that the memory is also limited by that number length. 32 Bit means up to 2^32 Bytes can be adressed, that's roughly 4 GB of RAM. In today's age that is not much. With 64 Bit the processor can adress 2^64. So you could have up to 9 Exabyte or 9 billion GB of RAM. If you have the money that is :P Source: I'm studying a combination of CS & EE Edit: I'm sorry that seems more like an age 10 explanation. Edit2: As an addition: You also can see the 32 Bit limitation on flash drives with older file systems because they have the limitation that a file may not be bigger than 4 GB, because the file size only has 32 Bit."], "text_urls": [[]], "score": [6]}}, {"q_id": "67uyjp", "category": "Repost", "title": "Why the numbers Eleven and Twelve not follow the same naming convention as the teens?", "title_urls": {"url": []}, "selftext": "I was just wondering why eleven isn't firsteen and twelve seconteen?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dgtercs", "dgteqd3"], "text": ["Most western societies used to use base 12 as its counting system. To understand what that is would be an ELI5 in itself, but basically rather than consider things in blocks or multiples of 10 like we do, they consider it in blocks or multiples of 12. So 11 and 12 weren't thought of as being part of the same group as the teens. France, under Napoleon, instead started adopting the decimal system. It caught on, but not until after our language had already decided on what to call those numbers.", "Depending on how you think about it, humans either make complete sense or they are completely illogical. A dozen used to be an important unit of measure. So, counting to twelve was important kind of as an alternative to counting to ten. And multiples of twelve (dozens) made sense. It is sort of like how our clocks use a weird mix of 24 hours and 60 minutes and 60 seconds to mark out a day made sense once, so we just sort of stuck with it. Notice that 24 hours is just twelve hours of day and twelve hours of night."], "text_urls": [[], []], "score": [19, 4]}}, {"q_id": "67v6nx", "category": "Repost", "title": "Why are birds and bees associated with talking to kids about sex?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dgth8ag", "dgtgp3b", "dgtgfx6", "dgtgxof", "dgthpe9", "dgtie0m", "dgtgzu6"], "text": ["Usually the first thing you learn about procreation is that of plants (flowers). The German expression is, appropriately, \u201cBienen und Bl\u00fcmchen\u201d, which translates to \u201cbees and flowers\u201d. There are male and female plants, and the pollen is the equivalent to sperm, while the blossom is the equivalent to the female parts, leading the pollen to the egg cell. Some plants are pollinated by birds instead of (or in addition to?) insects. So \u201ctalking about the birds and the bees\u201d (or the bees and the flowers) is a euphemism for talking about procreation/sexuality.", "I could be wrong but I think it's because birds lay eggs, women have eggs. Bees pollinate things, sperm pollinates the eggs.", "I believe the closest answer i ever found to this question was the female is represented as the bird, and the bee represents the male because of it's stinger (penis). Not really sure why the female is a bird though", "I always took it to mean the way birds and bees gather nectar from flowers. Then again, if you've ever seen a bird swallow a worm...", "I believe it's a reference to the 50's song. I forget the name. Singer might have been Sam Cooke. \"Let me tell you 'bout the birds and the bees and the flowers and the trees. And a thing called love.\"", "The idea of fertilization (which is the most important step of reproduction) is easily explained without using body parts by using flowers. It was usually taught this way, explaining how pollen is spread and how seed works. Birds and bees assist in this process and became the unofficial mascot of the conversation.", "I thought it was coz birds and bees are prevalent in spring time and thats when everybody in nature is mating"], "text_urls": [[], [], [], [], [], [], []], "score": [128, 56, 48, 23, 10, 9, 5]}}, {"q_id": "67x1ze", "category": "Repost", "title": "Why, when speaking on the phone, do I have a compulsion to walk in circles and touch random things around the room?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dgtyaul", "dgu91z4", "dguh4kv"], "text": ["Here's an answer courtesy of u/jambola2 [This mentalfloss article summarizes a lot of points on why we pace while we think, and I think it likely applies to while talking on the phone too.]( URL_0 ) Studies have shown that people are better at thinking of creative solutions while pacing about. Studies have shown that performing repetitive actions (like moving up and down in the same way) often has a destressing effect. Another study talks about how pacing about may be a somewhat involuntary response to stress and anxiety.", "Another possible theory is that (face-to-face) communication usually involves body language, gesturing, etc., and when you're on the phone you still feel the need to do something with your body while you communicate.", "Here, you go broseph. Search is your friend. URL_0"], "text_urls": [["http://mentalfloss.com/article/64404/why-do-we-pace-when-were-thinking"], [], ["https://www.reddit.com/r/explainlikeimfive/comments/4yhsio/eli5_why_are_we_inclined_to_walk_around_during_a/?ref=search_posts"]], "score": [214, 115, 6]}}, {"q_id": "67xrwc", "category": "Repost", "title": "What is Voltage?", "title_urls": {"url": []}, "selftext": "I get that it is a unit of electrical energy (Volts, also Joules per Coulumbe) but conceptually I don't get it.", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dgu1gi6"], "text": ["It's sort of like gravity, except it only works on charged particles (whereas gravity works on everything). So, charged particles operate in this weird world where there is another kind of \"gravity\" that pulls them in various directions. Make sense?"], "text_urls": [[]], "score": [4]}}, {"q_id": "681sqt", "category": "Repost", "title": "How did salt and pepper become the primary seasonings of choice?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dguzid0"], "text": ["Sodium, which is a major component of salt, is needed by the body for a huge number of biological processes. So, salt is pretty obvious as a favorite seasoning. Pepper became popular when people figured out that it could be used to cover up the taste of semi-rotten meat. Source: URL_0"], "text_urls": [["http://www.straightdope.com/columns/read/393/how-did-salt-and-pepper-become-the-standard-table-spices"]], "score": [5]}}, {"q_id": "684bpz", "category": "Repost", "title": "Why do laptops have \"waves\" going across the screen when looking through a phone camera, but they are not seen by our naked eye?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dgvki8j", "dgvkvmr", "dgvkcaf"], "text": ["It's called aliasing, or more exactly moire pattern: both camera sensors and LCD screens are made from pixels. Pixels are not contiguous but are made to either display (LCD) or capture (sensors) specific color, like red green or blue. Now when you focus your camera on laptop screen, the individual pixels on the sensor do not match the pattern of pixels from the LCD - you get a piece of adjacent red or blue pixel or even uneven number of LCD pixels projected onto sensor pixel - that causes unevenness of light exposure and thus a Moire pattern, which you call \"wave\".", "Imagine that you are looking through a fine net, like one of those nets to prevent small bugs from getting in the house. You can see no problems through the net but if you add another net, it is harder to see. You will also see these \"wave\" patterns when putting the nets on top of eachother. You can say that the holes in the net are pixels, and when these two layers are on top of each-other, the vision or quality of the video is lowered and you will see these wave patterns.", "It's called a moire pattern, and it's caused by the regularly spaces pixels in the camera not aligning perfectly with the regularly spaces pixels in the LCD display. Your eye doesn't use pixels, for this and many other reasons, so you don't se the effect with your eye."], "text_urls": [[], [], []], "score": [8, 6, 4]}}, {"q_id": "68902h", "category": "Repost", "title": "Why does for instance, fans, make the air feel cool on your skin even though it's circulating air of the same temperature?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dgwlx9z"], "text": ["The air movement increases the rate of evaporation from your skins surface. Because of waters high latent heat of vaporisation, evaporation uses a lot of thermal energy so your skin feels cold"], "text_urls": [[]], "score": [5]}}, {"q_id": "68aji7", "category": "Repost", "title": "Why is collecting rainwater illegal in the US?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dgwy3p1", "dgwybwi", "dgwy96e"], "text": ["Its only illegal in some parts of the US. I live in the Eastern US, where water rights are not fought over, and I can collect all the rain I want. If you go to the western US, water rights are very important. Lakes and streams are fed from runoff rain water. Think of it this way. If my neighbor downstream has water rights, I can not build a damn and cut off his access to water. In the same way, there are places that rely on runoff water, and if everybody were to collect it, places downstream would have no water. Often a small rain barrel is not an issue, but if everybody started collecting thousands of gallons of water, there would be problems.", "It is illegal in 9 states, not the whole U.S. On top of that, most of those states where it is regulated allows a homeowner to collect it from his roof. So a blanket statement of \"it is illegal to collect rainwater in the U.S.\" is wrong.", "It is only illegal in a couple states, and usually for safety reasons. Additionally, It's usually done by local governments, not on a large scale. In those few states, it's not, for example, having a bucket sit out that collects some water for your flowers. It's having a shit ton of barrels sit out to collect large amounts of water and/or fucking with dams/water manipulating devices without a permit from the state/local govt. One person doing this wont hurt many people, but if 50% of the people in the town do it, it can start to cause ecological issues. More Reading: URL_0"], "text_urls": [[], [], ["http://www.enlight-inc.com/blog/?p=1036"]], "score": [16, 3, 3]}}, {"q_id": "68bvga", "category": "Repost", "title": "Why is day divided in 24 hours and not some other number?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dgx94nd", "dgx9dc9", "dgx8xra"], "text": ["Its easily divisible. Decimals are a fairly new mathematical concept so having numbers that divide into a lot of things easily makes things easier. 24 into half, thirds, fourths, sixths, and twelfths.", "Do [the numerous previous answers here in ELI5]( URL_0 ) help some?", "People used to have bad math education and no calculators and didn't really standardize everything into base 10 like we do so having things be really easily divideable was the most important thing so lots of olde timey stuff is base 12 or base 60 or some multiple of that. Like a modern person, even one that is terrible at math has had years of schooling to not freak out when a third of 10 is 3.33333 repeating, but if you are some guy in the year 1200 then that is way way beyond you so you'd rather a third of 12 be 4 or a sixth be 2 or normal people numbers you can write without fancy ideas like decimal points."], "text_urls": [[], ["https://www.google.com/search?q=eli5+why+24+hours+day"], []], "score": [4, 3, 3]}}, {"q_id": "68d7zy", "category": "Repost", "title": "Why male and female adults get attracted to each another?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dgxk9de"], "text": ["To my understanding, it started out as a biological need to reproduce. A long time ago our sole goal in life to was reproduce so our bloodline continues. Our bodies would attract us to the other sex (and typically more towards someone \"hot\") because you would deem them worthy to carry on your bloodline with."], "text_urls": [[]], "score": [3]}}, {"q_id": "68dj11", "category": "Repost", "title": "Why does everyone hate Comic Sans so much?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dgxn4kp"], "text": ["I think because it simply got way over-used, in many contexts it wasn't designed for. It's casual, playful, and has a fun name, so a lot of people started using it for everything. Folks got tired of that, because it's annoying to have a sign in the breakroom with a serious message but a playful font, and the anti-comic sans movement was born. Remember Dolores Umbridge from Harry Potter? How annoying it is that she's always smiling despite the context, and how much everyone hated her? Comic Sans is kind of like that."], "text_urls": [[]], "score": [7]}}, {"q_id": "68en7x", "category": "Repost", "title": "Why do small language differences exist, as in \"color\" and \"colour\"?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dgxvsvc"], "text": ["In that particular case it's because someone in America made a conscious effort to reform spelling to make it more simple and distinctly \"American\". So they took the unnecessary 'u' in colour out, as well as turning 'centre' into 'center'. But in other cases it can't always be traced back to a specific thing. Sometimes words fall out of use in one place, or get replaced with new words, or they start being pronounced differently for no obvious reason. These changes will happen differently in different places when people who speak a language are separated."], "text_urls": [[]], "score": [4]}}, {"q_id": "68k80o", "category": "Repost", "title": "How do music makers know if a melody has been taken or not?", "title_urls": {"url": []}, "selftext": "If say a song you thought up just happens to have the same melody as another song you've never heard of that's already been published and copyrighted how would you know before you make a mistake of using that song?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dgz5omb", "dgzc837", "dgz7tay", "dgziye7", "dgz5q7c", "dgzfmg1", "dgzcv3f", "dgzcl72", "dgz9a09", "dgzdjrp", "dgzd1za", "dgzctnx", "dgzvtux", "dgzeaxg", "dgzhkq3", "dgzc0e7", "dgzck5e", "dgzfvot", "dgzcepl", "dgzcht5", "dgzkdy9", "dgze6xr", "dgzergz", "dgzcu48", "dh048qa", "dgzc4mx", "dgzcynn", "dgzf2w6", "dgzc494", "dgzhfi7", "dgzjxgv", "dgzhaft", "dh05qy6", "dgzqxsx", "dgze8eq", "dgzmgy3", "dgzlpl9", "dgzlkxo", "dgzct0l", "dh0225c", "dgzpgc6", "dgzl36q", "dgzncgn", "dgzlkfi", "dgzgh75", "dgzirtx", "dgzszve", "dh0g9cf"], "text": ["you don't. basically, copyright law is against *copying*; if you come up with the exact same melody by yourself, then it's fine, as long as you can prove that. to prevent people from abusing this, there's a rule that if you've had access to (heard, for example) a previous creation (in this case, the song) and your work is similar to that previous creation, then it will be presumed that you did copy and you have to prove you didn't (not easy). you can also be found to have \"subconsciously copied\". balancing this is the rule that if you didn't *intentionally* copy, you won't be required to pay damages, only enjoined (ordered by way of injunction) to stop infringing the original copyright (so you can't sell your song etc.) so if your song sounds similar to a popular one, you probably will be stopped from doing much with it even if you didn't consciously copy, but you won't have to pay crazy sums or anything unless you obviously intended to copy and profit from the original. edit: there are some other replies that say you can't copyright a melody. this is untrue; there is one copyright subsisting in the lyrics and another in the melody. this is why song credits list the songwriter/composer separately. second edit: the first edit is true in the UK and Australia. there's a comment somewhere here which apparently says that that's not the case in the US, but I can't tell for sure (don't know much about US IP law). third edit: some people are asking \"what about beats/chord progressions etc.\" basically, there's this concept of an idea-expression dichotomy in copyright law. copyright protects expressions, not ideas. to illustrate, if I told everyone to write a love story, they would probably come up with fairly different things. the idea here is \"love story\", but each writer has come up with a different *expression* of that idea, and each individual expression has its own copyright. the simpler an expression, the closer it is to the idea, and the more difficult it is to prove infringement of the copyright protecting that expression. the reason is that if you protect the idea, you basically give the holder of the copyright a monopoly over *every single expression of that idea*. so, in my love story example, that would mean that if I had copyright in it, I would be the only person who could ever write love stories, or allow anyone to. stuff like chord progressions and beats are very, very close to ideas. for example, the simple I-IV-V-I can be played slow or fast, loud or soft, on the trombone or the glockenspiel, in A Major or F# Major, etc.. when you step so close to an idea, you would have to copy someone more or less wholesale to be liable for copyright infringement.", "This is a pretty real worry for a lot of songwriters, who have to consider carefully if they've actually come up with something new, or if they'e suffering from cryptamnesia where they've simply forgotten where something came from. Paul Mccartney famously spent weeks shopping his melody for 'Yesterday' around people in the music biz, seeing if anyone had heard it before. Even if it does happen, there are ways for them to amicably handle any claims through the music industry's crediting and royalty system.", "There are actually a lot of musicians, songwriters, and producers who won't accept unsolicited music from people because of this. If they take your demo then sometime in the future they make a song that sounds similar to something on that demo it might be hard for them argue that they had never heard your song before (even if they just tossed your demo in the trash).", "As a songwriter, I'll just say that it's more difficult than you might imagine to accidentally create the same melody as someone else. This may be surprising since many of the most popular songs in the world use the same 2-3 chord progressions. There's a comedic team that does a medley of all the songs that use the Canon in D progression, and it's striking just how different the melodies are from one to the next, but they all work perfectly with the music. Now, sometimes you will get a similar melody for a few notes, sometimes you'll notice you're doing it, sometimes you won't. It wasn't until after I recorded a song for an album that I realized our chorus had the same three notes from the line \"Take On Me.\" A few people joked about it but mostly not, because the rest of the song is so totally different, and it's three notes. It happens. Even if you wrote a chorus with the exact same chord progression and tempo as another song, the chances of accidentally writing the same melody even for a few notes in a row is astronomical. If two songs sound similar enough to be copied, they probably are. The thing is it can be unintentional. I heard a song in a store yesterday, no idea who or what it was, but it was hip-hop. The hook was catchy. 30 mins later I found my brain writing a song in another genre around that chord progression, though I had forgotten what the melody sounded like. I decided to forget it just in case more of the melody I was dreaming up was from that song than I meant it to be, and even if it was, nobody would have ever put the two together if I'd released it. One funny story though, in regards to music and not vocal melody, Back in about 2005 I wrote an arpeggio riff that I played with guitar tapping; it was a breakdown-outro to a song. We recorded a demo of it but ended up leaving the song off the record we were writing because the rest of the song wasn't very good. Fast forward 11 years and the first half of that riff is now the theme for the Daredevil show on Netflix. I still plan on using that riff in a song though, because it's good, and I wrote it first, dammit. But do I think the composer copied me? Even if we'd released the song to the public, no, I would not think that. Here's my riff: URL_3 Here's the Daredevil theme, in the same key, no less: URL_1 Edit: funny thing, I heard the same melody from the beginning of this part in a classical song on the radio today. Edit 2: I just remembered another funny story, tangentially related. While writing that same album I mentioned, I had decided that [Escape from the Bomb House by Less Than Jake]( URL_0 ) was a great song and I would just rip it off. This happens fairly often too, and what I mean is that I liked the vibe of the song, I liked the chord progression, I liked the way I felt when I listened to it, and so I wanted to try to get as many of those same things together in a new song. This would probably mean using the same tempo and maybe some of the same chords, but that I'd fool around using that song as a base and eventually it would turn into something new. This is often how songs are written anyway, I'd end up writing something new while learning something else, so I decided I would do it on purpose this time. Well anyway I get my guitar out and start figuring out how to play the song and am surprised to find that we had already written a song with almost the exact same chord progression from start to finish! [Stitches by Much The Same]( URL_2 ) It's not exactly the same and it's in a different key, but if you're musically inclined you'll hear that if you removed the vocals and put it in the same key, the chord progression in the verses and choruses are almost identical. The reason this is related is because despite these two songs being similar, and me being a big fan of one as we wrote the other, the melodies are worlds apart. Of course I could not try to write another song with almost the same progression for the same album, so I dropped that idea. That brings us to now, when we are writing our newest album, and it turns out that two of our new songs, written by the same guy, are almost the exact same chord progression as each other, in the same key, enough that as we're learning them I keep getting them mixed up. Like so similar the way those two Nickelback songs can be played on top of each other. But they're both really good in their own way, and nobody would be likely to notice the similarity unless they tried to learn them on guitar, so whatever. =)", "Sometimes they don't. Sam Smith's song Stay With Me basically uses the exact same ~~chords~~ melody as Tom Petty's I Won't Back Down, which was written decades ago by Petty and Jeff Lynne. Sam Smith had no honest idea that the two songs shared that similarity, and no one had actually noticed until some lawyer/manager/whoever realized that the songs were similar enough to warrant some sort of royalty. So Smith went ahead and gave them both songwriting credits to avoid the legal headache that would've surely followed. EDIT: I get it, I get it, it was the melody. I'm sorry. Shit.", "I am a professional musician, and I have an issue with Deja Vu where I often believe the things I write or play, I've heard before. The thing I and my mates have found is that there is always a 90% chance someone has played the same progression of notes, chords, or rhythms, but rarely the combination of the three. So it is highly likely that there are chunks of songs that sound really similar all the time. But most of the time, the connection is never made, nor do people WANT to make it made. Much like politics, it's not illegal to be unaware. If it looks like you are copying large chunks of lyrics and music, there are unwritten rules about whether or not you get sued; like when Van Halen was informed that their song \"Jump\" sounded really close to an Australian 70s band, they just said \"Well, oops.\" The pursuit of any dispute was tossed because \"Jump\" is a million times more famous and popular. So, technically, if you do accidentally copy a riff note-for-note, just become the most popular version of the song. There is a website that makes a list of a lot of \"Suspiciously Similar Songs\" and most of them make no mention of lawsuits. URL_0", "In some cases they even copy themselves without knowing. A case brought against Andrew Lloyd Webber claimed that a song from Phantom of the Opera (1984) copied another artist's work from 1978. Webber eventually won because a music expert proved that he had written the same melody in Joseph and the Amazing Technicolour Dreamcoat during the sixties. URL_0", "They don't, and it happens often. The same thing happens in literature as well - Isaac Asimov once wrote a short story very similar to one which existed, and it so happened he had that book in his personal library although he may have never read it. Generally speaking the done thing in this situation (and the only legally sound thing, unless the other person is kind rather than greedy) is to give royalties despite the fact that you've done nothing wrong - which is what Asimov did, and many other artists who've been in that situation. This is similar to how people have been punished for plagiarism for having accidentally typed a sentence which has been typed before - it does happen, although in that situation you're kind of fucked.", "This post and the subsequent replies made me think about the near-lawsuit similarity between \"Ice Ice Baby\" and Queen's \"Under Pressure\". I think Vanilla Ice said it wasn't plagiarism because he tweaked the iconic beat (barely), but he still ended up having to pay up and tarnished his reputation in the process.", "[Down Under vs Kookaburra]( URL_0 ) is an example of this. Down Under came out in 1981, whereas Kookaburra Sits in an Old Gum Tree is from 1934. The original author of Kookaburra died in 1988, and the song Down Under is so iconic in Australia that it's difficult to imagine she hadn't heard it. Nonetheless nobody really noticed or talked about it until [it came up in a TV show in 2008]( URL_1 ) and the copyright owners pursued the case and succeeded, resulting in the flautist who played the riff on Down Under committing suicide.", "Some people do it intentionally but steal melodies that are in the public domain. I'm aging myself a bit here but the first example to come to mind is \"Groovy Kind of Love\" recorded by Phil Collins. The song (which Collins didn't write\" was a slowed-down version of the rondo movement of Sonatina in G Major op. 36 no.5 by Muzio Clementi, a composer from the late 1700's.", "They don't have to really, melodies and tunes are the same a lot of the time, you just don't notice it until it is pointed out. If you want a fun example of this check out \"The Axis of Awesome 4 Chords\". Shows the crossover of songs using the lowest common denominator. URL_0", "Isn't this exactly the problem that Pied Piper was originally going to address?", "John Fogerty got sued by his old label for making songs with his new label that sounded too similar to John Fogerty.", "Been writing music since I was nine. I can say at this point, I have learned not to worry too much. As long as I'm not ripping off some song note for note, it is all good with me. Fuck, I even rip off my own songs from time to time. Good music only has so many possibilities and thats why most of everyone's favorite songs all share the same melodic premise (firsts and fourths all day). To me, music is more about compounding knowledge and ideas to grow individuality by listening, studying, and enjoying music rather than trying to make it out of thin air in hopes to be something different. Posers are sick. I've also noticed even when you think you've came up with something original, it's actually partially (or sometimes fully) a song from your subconscious or already a song by like 92719 different people lol.", "The way they taught us in music comp is that you follow the 8 chord rule. Basically, an 8 chord progression would be considered a melody, and your progression has to be different by at least 1 chord. Almost all pop songs follow the same chord progression though, it just varies on the key, major/minor, etc.", "That just happened to Led Zeppelin for the arpeggio from the opening sequence to Stairway To Heaven. Someone claimed Zep stole it from them. They lost. Apparently it's been used dozens of times through history. Interesting stuff. Edit: Context + Embarrassing spelling mistake for a big Zep fan. ;)", "I'm seeing a lot of uninformed answers on here. People are misunderstanding a key difference. Melody isn't the same as chords. You have harmony and then melody. You cannot copywrite a harmony. (There are only 7 chords in a diatonic scale, and any other chord is outside of the key.) All of pop only uses 6 of the 7 chords. I,ii,iii,IV,V,vi. No matter what order they are in, you cannot copywrite that. The thing you are thinking of is melody. Melody is separate from harmony. You play chords and then a melody of the chords go on top. The reason axis of awesome does that is to show the harmony is the same. The melody isn't.", "I listened to a lot of emo music as a kid (yes I know) and I remember noticing a massive similarity between a Lostprophets song and an All American Rejects one. Both albums came out at roughly the same time, and the choruses are virtually identical. I always wondered how that happened, if it was just coincidence, or what. Edit: Not in any way supporting Ian Watkins. This was long before that news came out. Just noting the similarities between the two songs.", "For a good example of how these things can happen you can view this URL_0 The guy accidentally wrote the theme song to the office.", "Coincidently the song My Sweet Lord by George Harrison was playing on my computer because Spotify was promoting the Guardian of the Galaxy soundtrack. I looked up the song on Wikipedia to see WTF it was about. Apparently, that song was the center of a lawsuit that established the legal precedent for your question. I know it's just the Baader-Meinhof phenomena but it's still a weird feeling when that happens. Anyways here's the [link]( URL_0 ).", "There is nothing new under the sun. There are 12 proper notes on a guitar, piano...western tunings. Don't know about sitars and all that. There are lots of ways to play and arrange those notes but it's still just twelve. Amazing really.", "As a musician you will regularly re-write some of the dankest hooks ever written. I still feel the pain from the time I realised I had written Euthrymic's \"Sweet Dreams\" melody... about 20 years after they had.", "musicians steal from each other all the time. its practically a standard industry practice.", "Pied piper! It is a proprietary middle out software that allows you to search for copyright infringement developed by richard hendricks", "Spider Robinson wrote an award-winning SF short story about this decades ago. [Melancholy Elephants]( URL_0 ) discusses a future where all the creative works have been staked out.", "You don't... You rely on everyone you play the song to (before its release) to tell you if it sounds like something else. Even then stuff slips under the radar: URL_0 URL_1", "Very basically all music is the same. There isn't any new chord progressions there aren't any new notes. What makes each piece of music different than any other is how it's played and how it sounds overall. Think of those compilation video on YouTube where the band plays the same chord progression over and over again and then just does different parts of different songs that use that same chord progression. Technically they all have the same notes but what makes it artistic is how you present those same notes.", "They don't and it happens more often than you think and quite often there is no issue between the two creating artists. One of my fav examples URL_0", "Think of it like a book. All books that are in the English language are made up of 26 letters but they all tell a different story. It's just what you make of it", "I have a question regarding melodys and chords. I seem to remember someone telling me that you can copyright a melody, but you can not copyright a chord progression. That being said, i composed a song with a unique set of chords that obveously is based off of a melody that everyone already knows URL_0", "This is actually one of the [many] hazards of our absurdly long copyright terms. There's a pretty good chance that the melody has been used before, it's very difficult to find this out, and this problem is only going to get worse as more and more stuff gets copyrighted. There's a fantastic short story (in regards to this, combined with clinical immortality), but I can't find it :/", "Have you heard of this new app called Pied Piper?", "Would it be possible to play your melody into something like Shazam and see if there are any hits?", "My music producer friend says \"When your body starts tingling after you finish the melody, then you know that the beat is OG in your heart\".", "This actually happened w/ Guns n' Roses 'Sweet Child of Mine' and some Australian band who released a VERY similar sounding song years earlier. Somehow I don't think 80's sunset strip rock bands were listening to Australian pop music in the pre-internet era with easily accessible music, however take a listen and see what you think: URL_0", "On the flip side of some of these responses, which show music similarities, here's a melody you know that you won't recognize: URL_0 Don't spoil it for others please (Reddit now has spoiler tags, use them if you must), but you have heard this melody before. It's also cool as it's a one-time thing, you also won't be able to \"hear\" the video the same way once you learn what it is.", "I'm no musician, but I bet you can find precedence for most melodies in classical music which isn't copyrighted now. No, I didn't copy you, I copied Pachabel from the 1600's :-)", "They don't. I've heard people \"sample\" melodies before. Just the notes or a few notes were reused. But honestly it's hard not to use songs that you like in music you make. It's where we draw inspiration.", "As a band-member we usually write a riff or a full song and at some point either somebody asks \"Hey wait a second, isn't that how *so and so song* goes?\", or they don't and we never really think about it.", "Well they generally don't. But we used to play a game where we would write a riff. Then we would play it to the app Shazam and see what it would come up with, in an effort to create a unique riff.", "Would asking Siri help? \"Hey Siri what song is this\" and if it detects the melody as something familiar it will tell you the name of the song. Then you can compare it to your melody and see if it's the exact same", "Theoretically speaking how likely is it that a corporation could publish and copyright music algorithmically via a formula to copyright-squat on a likeness? I imagine all music is or will be owned by a few conglomerates and change their business model to a tiered license fee for would-be musician. How likely I this to becoming reality if it isn't already?", "I remember hearing Daryl Hall of Hall & Oates say Michael Jackson told him he got his idea for the bass line in Billie Jean from Hall & Oates' \"I can't go for that\". Daryl just said great, I'm flattered and left it at that. Didn't even think about a lawsuit. Good for him. The beats are similar, but not note for note.", "back when I was a student, I thought of a plan to write a computer program to create all possible melodies and put a snip of it on a website. doo dee doo. doo doo dee. dee doo doo, etc. Then I'd sue anyone who ever made a song. I was going to branch out and also make all possible word combinations, and sue about lyrics.", "There are not enough combinations of notes and chords to make the huge amount of music that we have now (and will have in the future) musically unique. See this track by the Axis of Awesome to demonstrate that sharing chord progressions is something very common in popular music: URL_0 Most song writers will know which chord progressions create certain emotions and reactions within people, and design tracks to embody this. Beyond changing the rules of music theory or the frequencies assigned with each note (for example) you wouldn't be able to guarantee uniqueness in tonality. This is why tracks have to be unique in other ways, such as lyrics, sound design, tempo, etc.", "I've got a fine example of that. Here is a moombahton track by Nadastrom, a project of Dave Nada, called [I!!]( URL_0 ). It was published in 2011, but went largely unnoticed. A few months later, Skrillex released [Bangarang]( URL_2 ). Guess what. It's pretty much a different song but with the same core. Did Skrillex hear and copy the track from Nadastrom? My guess is that unconsciously, he did, but probably he isn't even aware of it. What he made of that same core, is totally different, so even if it may have the same core, it is an entirely different piece of art. And that is what matters: it was *not* a copy. Did Skrillex get in trouble over this? Nope. Nor should he have been (IMHO). In general you'll only get in trouble for releasing similarly built up songs, if you're *very* successful, as in the case where [Led Zeppelin was sued over \"Stairway To Haven\"]( URL_1 ). And in that case, the similarity was *extremely* superficial.", "This metaphor isn't completely accurate, but melodies are like quotes. The quotes are made up of words in a particular order, just as melodies are made up of notes in a particular order. Even more, the quotes are made up of little phrases which help to make a coherent whole. Take the quote: \"say what you will, 'tis better to be left than never to have been loved\". You can say that maybe on the whole that the quote is original, but it is comprised of two very common phrases (\"say what you will\", \"to have been loved\"). How does someone know that they aren't coming up with a quote which has already been taken? They don't. The words they are using are shared by everyone else. Even more so, they are using common phrases. The simpler and shorter the quote, the more likely someone else had said it. The longer and more nuanced, the less likely it has been copied, or at least copied in its full extent. Though there are an infinity of ways to combine words, only so many of them make sense. You can make any mish-mash sentence which is unique, and it is only unique because nobody else would really want or care to say it. With melodies, many can be seen as a variation of a more simple melody. Anyway, my argument is that the less complex a melody is, the more likely someone else is to have come up with it themselves. The more complex a melody, the more likely it is unique. It being unique doesn't necessarily mean it is wholly original, as it likely shares a lot in common with a lot of other melodies. Even more so, most melodies are made of common phrases, and none of the phrases are original. It is the arrangement of these phrases which creates something more unique. It is an impossible question to really tackle because there are so many simple ideas out there that anyone could stumble on. Stairway to Heaven is a common example of a song that was plagiarized with the opening arpeggio, but opening isn't that hard to stumble across. Almost any Metallica song is like that. So many of the riffs are such that a novice guitar player could have made them (take Nothing Else Matters), but it just so happens that Metallica found them and realized their brilliance. I am of the opinion that originality ought to be less valued, and composition and delivery ought to be more valued. It isn't a problem that musicians come up with similar or even the same ideas, but it is how they execute those ideas that matters."], "text_urls": [[], [], [], ["https://www.youtube.com/watch?v=qvlJ-OJVFik", "https://www.youtube.com/watch?v=KFYFh8w4758&amp;feature=youtu.be&amp;t=17s", "https://www.youtube.com/watch?v=iIykLzlIHNw", "https://instaud.io/UNr"], [], ["http://tvtropes.org/pmwiki/pmwiki.php/SuspiciouslySimilarSong/Music"], ["https://www.google.com.au/amp/www.newyorker.com/magazine/2004/11/22/something-borrowed/amp"], [], [], ["https://www.youtube.com/watch?v=2Mfve0oxbPA", "https://en.wikipedia.org/wiki/Down_Under_(song)"], [], ["https://www.youtube.com/watch?v=oOlDewpCfZQ"], [], [], [], [], [], [], [], ["https://www.youtube.com/watch?v=165kMdtfp00"], ["https://en.wikipedia.org/wiki/My_Sweet_Lord#Copyright_infringement_suit"], [], [], [], [], ["http://www.spiderrobinson.com/melancholyelephants.html"], ["https://www.youtube.com/watch?v=sYiEesMbe2I", "http://ultimateclassicrock.com/george-harrison-my-sweet-lord-plagiarism/"], [], ["https://www.youtube.com/watch?v=KrLThSLBQv8"], [], ["https://youtu.be/hVla9pjp6js"], [], [], [], [], ["https://www.youtube.com/watch?v=oxqreCG0htQ"], ["https://www.youtube.com/watch?v=MbPufI-ulAE"], [], [], [], [], [], [], [], [], ["https://youtu.be/oOlDewpCfZQ"], ["https://www.youtube.com/watch?v=QicDzxQ_ImM", "http://www.rollingstone.com/music/news/led-zeppelin-prevail-in-stairway-to-heaven-lawsuit-20160623", "https://www.youtube.com/watch?v=YJVmu6yttiw"], []], "score": [4132, 1786, 528, 410, 332, 242, 182, 123, 121, 40, 35, 34, 27, 26, 26, 25, 22, 18, 14, 13, 10, 9, 8, 7, 7, 7, 7, 7, 6, 5, 5, 5, 4, 4, 4, 4, 4, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3]}}, {"q_id": "68lhok", "category": "Repost", "title": "Why do we look for life in earth-looking planets only? Couldn't other forms of life generate in other environments?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dgzcozm", "dgzcm5r", "dgzd89c"], "text": ["While it is highly likely that life completely different to what we have and know about on earth could exist somewhere in the universe, it is a lot easier to look for things similar to what we have on earth, as we know for certain that all life we are aware of is carbon based and at least requires food and water. We're already venturing into the unknown looking for life in space, so we can cut out a lot of variables and make the process a lot less random if we just look for life similar to what we have here on earth. It makes it less of a complete stab in the dark if we already sort of know what we're looking for EDIT: TL;DR: We know it works here, chances are it'll work somewhere out there too", "I believe it is because we have proof that life on earthlike planets could exist, since we are here, but no proof of life on any other kind of planet (yet). Looking on those planets should then, theoretically, increase the chances of finding it, since we \"know\" some kind of life form would be able to survive there. In my opinion, you are not wrong in thinking that other life forms could have wildely different criteria for survival, however some people do believe that for life to be formed, it needs water and oxygen like here in earth.", "When looking to duplicate results you look for as many similarities as possible in order to maximize your chances of success. We know with 100% certainty that earth can sustain life and so the greatest chance, with the knowledge we have, of finding another life form is on a planet identical to our own. From there you create allowable variances using information we already have (min and max temperatures we know life exists in, min/max pressures etc) to find similar but not identical planets in order to generate a list of candidates to investigate further. Once those have been exhausted you expand your tolerances to include more planets until you find what your looking for(or don't find anything). If we ever discovered another planet with life than whatever conditions that planet was in would be used to further refine our search criteria. Edit: here are too many planets for us to investigate all of them at random and the information we get too limited to not use a frame of reference like earth to compare against. However, we are searching for like or signs of life in nearby planets and moons in our solar system and if found would drastically change our search criteria."], "text_urls": [[], [], []], "score": [8, 3, 3]}}, {"q_id": "68lqpp", "category": "Repost", "title": "What makes some melodies \"catchy\" and others not?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dgzfb3d"], "text": ["Basically it depends on how easily one can sing the song. Composers will choose easy intervals and simple rhythms to make it as easy as possible for the audience to remember what was played or sung. This goes back to Mozart and even farther. You would most likely remember a Mozart tune better than you would a Wagner tune, because Mozart wrote easily singable melodies, and simple rhythms. Listen to a song you think is catchy one time, then sing it back. We remember catchy music because we don't have to pay attention to it. It's just there and it's easy."], "text_urls": [[]], "score": [6]}}, {"q_id": "68n3zz", "category": "Repost", "title": "Why is prostitution illegal?", "title_urls": {"url": []}, "selftext": "Commonly called the oldest profession in the world, prostitution has been around as long as people have formed societies. Unlike legalization of drugs or alcohol the use of it puts no ones lives in danger. In fact it may be able to save some. So what is the problem?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dgzp9g2", "dgzp5k2", "dgzpkxt"], "text": ["It's too hard to tax. The government doesn't want people getting off without giving them a little reach around.", "That's where many people don't realize the extent of sex trafficking. Many prostitutes are forced into it either through extortion for money, or trafficked into it (happens to a very high extent in Asia and Eastern Europe, even in the Americas). This is a violent, drug-filled, exploitive, unhealthy, and utterly immoral trade to engage in. To discourage this, it was made illegal, but some countries realized that it might cost more to prevent all of it than to allow it under strict regulations.", "> it puts no ones lives in danger. Because, in many instances, this statement is blatantly false. For that to be true, it assumes complete agency on the part of the sex worker. I.e. the sex worker is voluntarily selling their body. In many scenarios, this is not the case. The sex worker is frequently forced or coerced into prostitution through threat of violence or other forms of control (drug addiction, control over someone's passport, etc.) Even in scenarios where the sex worker has taken up prostitution on his/her own, it's a private, physical act that carriers with it health risks for both parties, as well as the risk of violence from one party against the other (particularly since it occurs behind closed doors). Those risks may be deemed by society to be too high or impactful to allow the activity to occur _at all_, and so it is made illegal (I would personally argue that you can better mitigate those risks by *regulating* the activity instead of banning it, since banning it drives it underground and _increases_ such risks. There may be less of the activity overall than there would be if it were legal, but the remaining illegal activity that does occur is of much higher risk to the parties. It's basically a trade-off between ubiquity and harm.) And, of course, there's the moral / religious argument, which is only valid so far as all parties involved agree with that moral / religious basis."], "text_urls": [[], [], []], "score": [19, 6, 4]}}, {"q_id": "68snxt", "category": "Repost", "title": "why does 70 degrees inside my house feel considerably colder than 70 degrees outside?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dh0xrvg"], "text": ["Air conditioners also dehumidify the air to a degree. So any humidity that would make it feel warmer outside is reduced drastically. 70 degrees with no humidity will feel cooler than 70 degrees with 30% humidity."], "text_urls": [[]], "score": [3]}}, {"q_id": "68t7ii", "category": "Repost", "title": "What caused the recession in 2008?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dh13e17"], "text": ["This one is a bit complicated, but at the core, this is an issue with **confidence**. When a Bank loans you money, they do it in the hope that : a) you pay back the loan you have taken (like if you ask for 100 000$, you pay back 100 000 dollars), and b) you pay back interest upon the sum of money they lent you The amount of money a bank gain each month is Benefit = Sum_lent x interest_rate. As a bank is a company, their role is make a benefit, pay their employees (and other bills) and give back dividend to their shareholders. So they want to make more benefits. And there are three ways to do that : A) Increasing interest rates, which an work, but if you ask a interest rate too high, a customer will try to get a loan elsewhere. So its not very sustainable. B) Lending more money. But most people asking for money and able to easily pay back already get the amount they asks. The only way to do this is then to loan money to people which could have difficulties to pay back the loan. It's not especially a good thing, since if a guy default on his debts, the bank **loose** money. SO they have to get a higher interest rate to compensate the risks, and people probably would want a credit too expensive. That's where the **subprime mortgages** comes. The prices of housing was growing regularly, and at a relatively high rate. Banks decided to create a loan which was available to relatively unsafe borrowers ate the condition it was used to buy a house, and that the house were to be taken by the bank if the borrower could pay back. On the paper, it was extremely safe : if a borrower pay back, the bank made money, if the borrower don't, they get a house worth about as much as the money they lent (which they could then sold), and all the payment already made. On the other side, it was relatively nice for unsafe borrower (called **subprime borrowers**, usually poor people) to be able to buy a home, at a moderate cost (since it was relatively safe for the banks, they used a rather low interest rate). The issue came when the a lot of these subprime borrowers couldn't pay. The banks seized their homes and tried to sell them. At this point, the price of houses was high because people expected to be able to sell their homes at least at the price they bought them, probably more. And as people were expecting to be able to do the same, they kept buying. That's a **price bubble**, where rising prices of something make people buying this stuff to sell it later with a profit. But when the banks tried to sell them, there were not enough people trying to buy house to buy them all. In order to avoid loses too high, banks tried to sell them a little bit less than their value. It made the **bubble burst** as people were thinking \"I'm not sure I can get a profit anymore, better wait a bit to see what happens\". And then, everything went to hell, and no wanted to buy at the market prices for houses, forcing banks to sell at a lower prices, which in turn made people wanting even less to buy... And since the houses were a mean for banks to limit loses, they weren't able to avoid taking HUGE losses (think billions of dollars). They lost so much money that the debts the banks contracted were higher than the market values of the banks. Therefore, banks were on the verge of bankruptcy."], "text_urls": [[]], "score": [3]}}, {"q_id": "68tkky", "category": "Repost", "title": "Why is Reddit's search so bad?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dh15w40"], "text": ["Conspiracy answer: It's intentionally busted, because if the search works well, you might find that your \"clever awesome post\" has already been posted a dozen times, and you won't share it. If you *can't* find that you're reposting something, you'll post it, get views, get comments, get traffic, and make Reddit feel like it has more content than it really has. Probably the real answer: Making a great search system is very complex, especially when it's searching through an enormous amount of posts, comments, links, etc. Keywording is really important, and most reddit users don't know anything about search engine optimization. Posts aren't really made in a way that allows them to be catalogued easily. So even if you're searching the exact title of a post that you saw 10 minutes ago, the search is still barreling though 10 years and billions of posts from tens of millions of users to try to find something, and it's going to struggle, a lot. One of the main reasons Google is our overlord today is because they came up with great (proprietary) search equations. It's very hard to do."], "text_urls": [[]], "score": [5]}}, {"q_id": "68v8y4", "category": "Repost", "title": "Why can a company ship me a package from Sweden to US for free, but if I try to ship it back to their address it costs me $100?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dh1jgpf", "dh1jgx2"], "text": ["Nothing is \"free\". The cost is covered by you. You've paid shipping, it's simply buried in the cost of the goods you purchased.", "So two things. The company pays for the shipping, they're just including it as part of the price of the item you're paying for. Large companies can get really good deal on shipping because they buy it in bulk. Individuals can't get those deals. Likewise, large companies often are able to save money on international shipping by loading up shipping containers with their products, which then get shipped locally. You can't get that sort of deal as an individual."], "text_urls": [[], []], "score": [4, 3]}}, {"q_id": "68zqb8", "category": "Repost", "title": "why does tensing your legs help you reach orgasm?", "title_urls": {"url": []}, "selftext": "E: holy shit 6k upvotes. E2: just a note, I did my search beforehand and apparently I didn't do it correctly. Move on. E3: reposts should be considered on a case by case basis. Or somehow allow archive posts to be marked active again or at least commentable. New information can be discovered by simple conversation in a short time period. You can't expect people to get an answer to things from the past if the previous post either didn't answer the question or is outdated (not saying that's my case but just makes sense for others).", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dh2nbra", "dh2m8jx", "dh2uyu9", "dh2xiso", "dh30iyb", "dh3027y", "dh2qh78", "dh2v7td", "dh2uyod", "dh30it8", "dh2q2im", "dh2sjw3", "dh2sss1", "dh2uqp6", "dh30obu", "dh2qv1l", "dh30hwl", "dh2y8vw", "dh31gey", "dh31edb"], "text": ["Best ELI5 Answer from the previous thread - An orgasm is, partly, an uncontrolled muscular spasm. By tensing up your legs, you're tensing up other things, and by other things, I mean your ass, since it's hard not to when you're tensing your thighs. When you tense up your ass, you also tense up everything in the general pelvic area, including the muscles involved in the orgasm. In this way, you're helping those muscles reach the point of necessary release faster than they would on their own, leading to a quicker pay-off. It also seems more intense because you're involving more of your muscles in the process, combined with the relaxation of everything once you finish.", "Has some interesting answers to this repost URL_0", "You're not flexing just your legs, you're flexing your quads, glutes, and kegels as well. Tensing these pushes your pelvis forward, which is the best position for insemination. In females, the height of this flexing straightens the vaginal canal and aligns it with the opening of the cervix. In males, the height of this flexing also creates the greatest pressure of ejaculation which results in deeper insemination, and more ejaculate being released in total. Prior to climax, you're not just flexing and holding, you're flexing and then relaxing repeatedly. Flexing forces more blood into erogenous zones, giving nerves the oxygen needed to keep sending pleasure signals from activity. Relaxing allows deoxygenated blood to drain from the erogenous zones. This process of pleasure reward for optimal reproductive actions is a product of evolution. You flex because it feels good. It feels good because it works (i.e. successfully encourages reproduction).", "I'm sure this is buried, but just in case you read it - consider posting to AskScience, which limits the answers to only fact-based ones. Lots of speculation in this (and the linked) thread.", "I have a feeling this has been answered already... But, from my perspective as a urologist... The muscles involved most directly during an orgasm have closely linked nerve roots/nerves to those innervating the muscles of the upper leg. Specifically, these will be the adductors of the leg (the muscles that allow you to close your legs). As an example, in men... the obturator nerve, that controls the adductors, runs alongside the prostate gland and innervates the muscles around it, too. When the leg muscles contract, those around the prostate do as well (a bit more complicated than this, but that's the gist), and that *squeeze* feels good during, or before, an orgasm.", "Anyone else here have trouble cumming when you jerk off standing up? I don't know why but I just can't jerk off standing up, like in the shower. It's way too much effort. If I lay down, I can crack one off quickly if I have to.. say my wife's out in the garden or something, but if I'm standing up it takes forever.", "Tensing your legs bring more blood to your pelvic floor area, thus increasing sensation and the urge to orgasm. If you are a guy trying to achieve a \"normal\" orgasm without tensing your legs, try tensing your balls instead. It will have the similar effect of forcing more blood to your pelvic floor area.", "Man, i think i am the only one here who when i tense my legs, i lose my boner. So it does the opposite of what OP is saying. Pretty cool trick when you are out in public , like on the bus, and you need to lose your boner quick.", "Tensing your legs helps increase venous return of blood to the heart by literally milking the blood in your veins towards the heart. This increase in blood volume to the heart increases cardiac output, stroke volume, and therefore increases mean arterial pressure. That means more blood is flowing out to your body and in this case, to your sexual organs. Increased blood flow helps you achieve orgasm. Source: Anatomy and Physiology class I'm taking right now. We just finished heart and blood vessel physiology.", "I can't get even get close without tensing my legs. I thought it was just me. It may have to do with forcing more blood into the torso and contributing to engorgement.", "Blood flow in that area man.. ever hit legs at the gym after 4 days no whacking it and using a test booster like d-aspartic acid? It aint only two legs that get a pump.", "Holding your breath also helps a lot. That's why people wind up choking themselves with belts and dying. I always figured they were related. Tensing up your muscles burns oxygen in your body.", "Because you don't know how to kegel and when you flex your legs it activates those muscles.", "It may not be the legs as much as you accidentally doing kegels as well. Those really help you finish quicker.", "Works both ways - to last longer, relax your lower body and legs when you think you're getting close. Wish I knew this trick years ago.", "Because tensing your legs facilitates greater blood flow to your genital region, and then this greater blood flow facilitates tumescence (swelling) of the genital tissues, which is instrumental in orgasms. Similar to how compression stockings work to prevent blood clots.", "This is... a thing? Never heard of it.", "I do that when receiving head. Had a mind blowing orgasm once. Felt like a wave building from my fingers and toes, and eventually through my dick. Was awesome.", "It's a learned behavior - if you did this during your first orgasms ever you are likely to continue using it and then orgasming without it becomes difficult or seemingly impossible. But it's reversible through some focus and exercises. You may have to train your patience while practicing cause it's not a speedy process. I SERIOUSLY recommend checking out work of Dr Betty Dodson, sex educator who taught many people how to overcome this. She answered this question on youtube. She's inspirational and more people should be aware of her work. Tensing your muscles stops the easy flow of orgasm wave through your body and feels like an explosion or implosion while tension free orgasm lasts longer and feels like multiple waves you can ride with practice. Also sounds like a song compared to tension grunts.", "I believe it isn't as much the tensing bringing the orgasm as the orgasm bringing the tension. When you orgasm, for both men and women, muscles tense and cause an explosion of, well there isn't really a sciency word for it, sexual excitement. Now my answer is somewhat wrong as it is believed that it is the tensing of muscles around certain glands that cause this release, but in reference to the leg tensing I do believe that it is a product of the orgasm as opposed to a cause. If you would like to think of it this way an orgasm is commonly thought of in stages, there is the build up when you first scratch the edges of orgasm, the plateau where almost maximum pleasure is achieved (usually where you begin to feel the tension in your legs), the release where the maximum pleasure is commonly achieved (usually when you find that tension at it's max or releasing) , and then the fall (or the afterglow as some call it). Some stages can be enhanced by a change in pace or motion or can be skipped over all together depending on the person. For males the orgasm tends to be shorter and more focused, and for women the orgasm tends to be an all over experience, although this is not solid fact as orgasms and sex are fairly hard to research reliably due to sex being a rather personalized experience and hard to generalize."], "text_urls": [[], ["https://www.reddit.com/r/explainlikeimfive/comments/2p4jnj/eli5_why_does_tensing_my_leg_muscles_help_me_to/"], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], []], "score": [4253, 3084, 746, 306, 76, 74, 34, 27, 17, 10, 10, 9, 5, 5, 5, 5, 4, 4, 4, 4]}}, {"q_id": "691ykn", "category": "Repost", "title": "Why exactly is it that 2 negatives make a positive?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dh31zl9", "dh35b91", "dh32qhm", "dh34qct", "dh327t6", "dh3qlty"], "text": ["because the first one is negative. The second one reverses the first one. A car is blue. A car is NOT blue. A car is NOT, NOT blue. < --- so, the car IS blue then.", "A good analogy from another thread on this was a car on a road. Assume a North-South Road with North being + Car can face North (+) and go forward (+) = travel North (+) Car can face South (-) and go forward (+) = travel South (-) Car can face North (+) and go reverse (-) = travel South (-) Car can face South (-) and go reverse (-) = travel North (+)", "In English, they don't. It's just that back in the late 1800s, a number of English speakers started trying to import Latin rules into their English in an effort to make their English sound more \"proper\" than that of the unwashed masses. Whether or not one acquiesced to this change signaled how submissive one was to authority figures. English was divided, into those who spoke \"properly\", and those who spoke the way English had always been spoken, with \"improper\" speech becoming grounds for prejudice. It's possible you ain't never heard of nothing like that before. It is *impossible* that you needed to count the negatives in the preceding sentence in order to understand the meaning (assuming, of course, you are a native speaker). Sometimes negatives counteract each other. Other times they accentuate each other. It isn't difficult to discern which case is which, and the only reason to argue otherwise is pedantry motivated by a desire to assert one's superior class.", "The negative is the additive inverse. That is, if you have a number and you add another number to it, you can add the negative of the second number to the result to get the first number back again. An inverse is literally just the same thing in reverse. Imagine it like turning 180\u00b0. If you do it twice, you're facing the original direction again.", "~~You've got ten dollars in the bank. You have a debt of 5 dollars to the bank. The bank offers you a coupon which cancels your debt. Equation:~~ ~~(+10) - (-5) = positive 15~~ You are taking away a debt. It's as if you have harvested 20 apples, but you need to give 10 of them to your robot overlords, which means you would have 10 to keep yourself. Suddenly, the robot overlords die inexplicably or no longer require apples to function. You no longer owe those 10 apples, therefore you now have 20 apples to keep yourself. EDIT: crossed out the idiotic parts", "if you're willing to follow a little bit of silly but not at all too complicated math: (1 + -1)^2 = (0) ^2 (because 1 + -1 is 0) (1 + -1)^2 = (1)*(1) +(-1)*(1) + (-1)*(1) +(-1)*(-1) (Quite a few 1's, but it's just the distributive property) 1*1 is 1 1*(-1) = -1 (by the definition of 1, anything multiplied by 1 is itself) so with some cleaning up that gives 1 + -1 + -1 + (-1)(-1) and this equals 0 by the first line. so then the 1 and first -1 cancel: 0 + -1 +(-1)(-1) = 0 and then solve (-1)(-1) = 1 and from here it should be clear why it works for all negative numbers, take -5*-9 = (-1)(5)(-1)(9) and you just collect the -1's to get 1."], "text_urls": [[], [], [], [], [], []], "score": [43, 9, 4, 3, 3, 3]}}, {"q_id": "6933lj", "category": "Repost", "title": "Telling people not to sleep and to fight loss of consciousness after a serious injury", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dh3c9d7"], "text": ["Having people stay awake is mostly for diagnostic purposes. Whether they can stay awake is a data point, and if they are awake you can ask questions. We naturally want to sleep so the body can repair itself, sleep on its own is actually okay in most cases."], "text_urls": [[]], "score": [9]}}, {"q_id": "693b8l", "category": "Repost", "title": "- If camera lenses are circular, why are pictures rectangles?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dh3dzp1", "dh3e0cb", "dh3gvb2", "dh3fof5"], "text": ["The lens is not what actually captures the image. The lens focuses the light and allows it in to whatever type of sensor you are using, such as a CCD for a digital camera, or chemically treated film for an old camera. It's the shape of the sensor that determines the shape of the photograph.", "They can be circular the shape of pictures has to do with the media receiving light from the lens Typically film is either on a strip or a plate, but you could expose a round negative, or with digital the I believe CMOS sensor is typically rectangular but there's probably no reason you couldn't make it round or any other shape.", "Many people have answered that the sensor is rectangular, but this, in my mind, just brings up other questions. Like: why would the sensor be rectangular? As far as I've understood this is because the human field of vision is more wide than it's tall. There is a post on stackexchange with a bunch of details and a short paragraph explaining below them. URL_0", "Because the photo sensor is rectangular! If you take a lens constructed for an APSC sensor and mount it on a camera with a full frame sensor (which is larger than an APSC sensor), the picture will be circular but the image itself (like the file on the camera or your pc) will still be rectangular. That basically shows the effect of the lens and the function of the sensor :)"], "text_urls": [[], [], ["https://biology.stackexchange.com/questions/24046/if-human-eyes-watch-an-area-whats-the-shape-of-its-capturing-shape-rectangula"], []], "score": [21, 4, 3, 3]}}, {"q_id": "693ycc", "category": "Repost", "title": "sometimes when I'm falling asleep I'll jolt myself awake and feel like I tripped over my feet and was falling, my co-workers say they experience this also. Is there any explanation?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dh3jk40"], "text": ["It's called a [hypnic jerk]( URL_0 ) and apparently happens to lots of people. I like the possible explanation that the primate part of your brain thinks you're about to fall out of your tree."], "text_urls": [["https://en.wikipedia.org/wiki/Hypnic_jerk"]], "score": [4]}}, {"q_id": "695pz8", "category": "Repost", "title": "How did bigbang happen and where did the stuff before bigbang came from?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dh40fzc", "dh40t7h", "dh48cle"], "text": ["There currently is no known answer to these questions. There are a bunch of theories, but scientifically, we know little to nothing of the moment of the big bang and anything that may have happened before it.", "I think the best explanation I read of it so far was: \"In the beginning there was nothing, which exploded.\" basically for the time before the big bang you have to switch off your common sense, as the big bang seems to have been the time when universal standards like time and dimensions came into being. So there was no before, because there was no time before.", "I have always liked the big bounce theory, the gist (to my understanding anyway) is that the universe expands to a point where it can't sustain itself, collapses in on itself and once it reaches a point of infinitesimal smallness and density re-expands into a new universe, perhaps with new laws of physics, rinse and repeat for eternity. Maybe the energy from the collapse of the old universe transfers to the new universe allowing the expansion. A new question is raised with this theory is how did it all begin and if this theory is correct how many universes have there been before?"], "text_urls": [[], [], []], "score": [13, 12, 4]}}, {"q_id": "696mtt", "category": "Repost", "title": "Why do some sounds make people shudder/cringe?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dh45jqo"], "text": ["I believe that would be because of [Sensory Overload.]( URL_0 ) Where when one of the body's senses gets so overwhelmed by stimuli, it is unable to handle what it's processing. Some people have sensory processing disorder, where this sort of feeling can be easily caused by other things, such as a crowd of people talking, or the sound of fabric scraping against itself."], "text_urls": [["https://en.wikipedia.org/wiki/Sensory_overload"]], "score": [7]}}, {"q_id": "696trn", "category": "Repost", "title": "How does my phone/laptop measure what percentage of its battery's charge is left?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dh48dty"], "text": ["Let's say a there is a battery with 2V. This battery may be full at 2V and 1V when allmost empty. Your phone or your laptop will take that voltage reading and will calculate how much power has left to your device. This is the way where you calculate the percentage by measuring the voltage. To be more specific your phone uses a fuel gauge ( Coulomb counter ) which measures the consumed current , then it compares it with the battery capacity and shows you the percentage. This cant be totally precise because of the way some batteries work. LiIon batteries which operate at low temperatures can lose some of their power and the counter isn't able to calculate it. Also batteries after some years lose some of their \"health\" due to overcharging, damages or other issues. This has as a result of inaccurate percentages from the coulomb counter."], "text_urls": [[]], "score": [25]}}, {"q_id": "699i59", "category": "Repost", "title": "Why do we enjoy and have emotional reactions to music?", "title_urls": {"url": []}, "selftext": "Why do I get a tingling sensation down my spine when certain tones in music play? Why do certain a songs make me cry? Why do I play songs on repeat when I'm exercising intensely because it seems to give me more energy?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dh59vzu"], "text": ["One of the many reasons(I'm not claiming to know them all btw) is that music is made up of fundamental frequencies. What's interesting about this is that our brains naturally resonate with fundamental frequencies and from this we feel something from the music. However this idea isn't just limited to music but it is limited to frequencies below our hearing range. For example say if somebody was to play a sound whose fundamental frequency was 11hz(not entirely sure if this is the right number) and if they did it loud enough, it would hurt the listeners eyeballs because the eyeballs themselves have a fundamental frequency of 11hz. In a nutshell because songs are made up of a number of different ones, utilising different timbres, across different instruments they resonate with our own fundamental frequency. I'm not entirely sure if If I've got all of the science correct(amateur music producer) but it's roughly there."], "text_urls": [[]], "score": [3]}}, {"q_id": "699vyg", "category": "Repost", "title": "What is the difference between fascism and communism?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dh4x0s4"], "text": ["That's not really an apples-to-apples question. Communism is a set of economic systems that share certain characteristics - mostly that the workers (manifested as the communist government) owns and operates the means of production. So, ostensibly, the people who make shit are in charge of what happens to that shit and how it gets distributed. This is pretty much as far Left as you can go. There is no private property - all property is held communally, but this in practice means the government runs everything. Karl Marx had a phrase that summed this up: \"From each according to his ability, to each according to his needs\". Strictly speaking, communism is economics only, and all other baggage with that (say, in Soviet Russia, or Mao's China, or Cuba) is not really part of communism per se. Typically communist governments devolve into totalitarianism before too long, but it's important to note that this isn't really part of communism as such. Fascism is a very loose term that can apply to many different situations. The terms as we use it comes from Mussolini's Italy, and basically it's a super-right-wing nationalist ethnocentric militant government (in rhetoric or violence) that puts the nation state above the individual. There's not *really* any specific economic system associated with fascism, but usually it starts with free market capitalism and then the state will take over businesses or co-opt them to work for the state, so in that regard it can resemble communism a bit. As you might be able to tell, extreme sets of ideologies break down the Left-Right spectrum of politics, as they kind of wrap back up on each other. There are other interpretations of the political spectrum that account for this, such as the [Horseshoe Theory]( URL_0 )."], "text_urls": [["https://en.wikipedia.org/wiki/Horseshoe_theory"]], "score": [8]}}, {"q_id": "699zc4", "category": "Repost", "title": "Why are there two different screwdrivers (Phillips and Flathead) Wouldn't it be much more useful to just only use Phillips head?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dh4xpv0", "dh4xwot", "dh4y0zj"], "text": ["Slotted screws have been around for centuries. Phillips head screws came about in the 1930's. The Phillips head was better for assembly lines because it works better with power screwdrivers. With a regular slotted screw, you have to line up the screwdriver in the slot just right. You also risk overtightening if you keep applying torque. With a Phillips head, if you get the tip of the screwdriver anywhere near the center of the slot it will slide into place. And since the slot is more shallow, if you keep apply torque after the screw is tightened, the screwdriver will slip out of the slot. Both of those things were important for power screwdrivers since it could be a pain to line them up perfectly with screws on a fast moving assembly line and because it was easy to overtighten with them. Slotted screws still have some advantages, though. The slot can usually be deeper, which helps it resist stripping. And if you do strip it, you can always make the slot deeper on your own. A Phillips screwdriver requires machinery to make and strips more easily since the slot is shallower. Also, you can use almost anything to turn a slotted screw if you don't have a screwdriver on you, whereas you need a Phillips head screwdriver to turn a Phillips head screw.", "There are lots of different types of head, each with their own benefits. A flathead for example is very easy to machine compared to others. Other screw heads may be less likely to cam out, or be *designed* to cam out so as to protect against stripping the threads. Still others are just obscure so as to discourage unauthorized or unskilled persons poking around where they shouldn't.", "There's actually a lot more than just these 2 types, and it's mainly all about application. The slotted screw head was one of the most common because it's cheap to make and can be easily screwed in by hand, but it was prone to the screw driver slipping out or being off center, so someone created the Phillips head, where the screw driver would self center and have a smaller chance of slipping out, so that's one of the most common now. But with these 2 types, stripping the head was a common issue in higher torque applications, especially when an electric driver is used, so other kinds were invented, such as hex bolts, used with sockets. Allen/hex heads, for example, were made to be used in tighter/smaller areas."], "text_urls": [[], [], []], "score": [11, 9, 9]}}, {"q_id": "69a3t8", "category": "Repost", "title": "When your nose is blocked, why does each nostril take it in turns to block/unblock depending on what side you're lying down on?", "title_urls": {"url": []}, "selftext": "Why can't they decide? I have a cold :(", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dh4zw7m"], "text": ["Actually the answer to this question is a little known fact about the human body. Our noses have cavities. These cavities are the tubes that bring the air we breath through our nose into the lungs. Rather than being clear tubes where the air can just pass right through, our nasal cavities have inward projections called turbinates which serve to narrow the passage and increase the overall surface area of the cavity. Why is surface area important? Our noses act to humidify the air we breathe so it does not dry out our lower airways and the increased surface area allows more of this humidifying to occur. Now, what most people do not know is we have something called a nasal cycle. This cycle happens every day, automatically, and it serves many purposes. What happens during this cycle is the walls of the nasal cavity fill with blood in one nostril and they decrease blood in the other nostril. This effectively narrows one of the cavities and opens another one. This happens every day but usually we don't notice it because both cavities still remain open. When we are sick, the walls of the cavities are already inflamed and narrow so when the cycle fills one side with blood, this side becomes even more narrow and eventually blocked. For more info look up nasal cycle."], "text_urls": [[]], "score": [4]}}, {"q_id": "69c2zi", "category": "Repost", "title": "Why is it if you pick up someone when they are limp (dead weight) it feels heavier than when they're not?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dh5g9kx"], "text": ["When being picked up you subconsciously shift your weight. If you are unconscious, then you aren't an active participant anymore, this your weight isn't being shifted to assist the person picking you up"], "text_urls": [[]], "score": [4]}}, {"q_id": "69c9ze", "category": "Repost", "title": "What's the difference between a 32 bit and 64 bit computer?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dh5haej", "dh5h4o9"], "text": ["Inside the processor are chunks of memory that hold a single value, called a \"register.\" In a 32 bit processor, the registers are 32 bits \"wide\", meaning they hold a 32 bit chunk of data. In a 64 bit processor, they hold a chunk of data that's 64 bits wide. A special register, called the \"stack pointer\" holds onto an \"address\" which holds the location in memory of data that the processor uses to load things into its other registers, or to store the data when it's done. Each possible value of the stack pointer is the address of a single byte (8 bits) of data. If the processor has a 32 bit wide stack pointer register, that means it can access up to 2^32 different bytes of data in memory. That's just over 4GB of memory. Plenty for the vast majority of applications, but it's a limitation. If the processor has a 64 bit wide stack pointer register, it can access 2^64 bytes of data, which is around 16 exabytes of memory (16 million terabytes). Clearly that's a winner. In addition, decimal numbers are commonly stored as 32 bit values. With some trickery, you can use a 64 bit register to hold two 32 bit values and process them at the same time. This can speed up some calculations. I should mention that accessing more than 4GB of memory is possible with modern computers, which use some extra tricks to get around the issue. In addition, modern Intel based processors have a few 128 bit wide registers that are used to process four 32 bit numbers or two 64 bit numbers at the same time. If you see a piece of software that requires \"SSE\" support, that's what it's referencing. Lastly, highly optimized software manipulates the fact that values are stored as 32 bits on older processors. Without the processor manufacturing offering backwards compatibility with the new hardware, or the developer reworking the software, it won't necessarily work on a 64 bit system if it was designed to work on a 32 bit system. This is more rare than you would think, because most people aren't manipulating bits at the processor level. It still pops up in some multimedia software.", "The value refers to the size of the processor's registers. A register is simply where the processor stores a value for computation. So a 32 bit processor can compute values up to 2^31 or 22,147,483,647. Why not 2^32 you ask? Because the last bit is used to encode the sign + or -). A 64 bit processor can compute values up to 2^63 or 9,223,372,036,854,775,807. This has implications for memory limits as well. A 32 bit processor can only address around 4 Gigabytes of memory where as a 64 bit processor can address around 16 Terabytes! Of course no PC exists that has 16 Terabytes of RAM, but the old 4 Gigabyte limit was a serious impediment to personal computing, which is why all personal computers nowadays use 64 bit processors."], "text_urls": [[], []], "score": [4, 3]}}, {"q_id": "69dnkf", "category": "Repost", "title": "What is the source code of a game? Why was the golden disk so valuable?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dh5rnqc", "dh5rj6f", "dh64gbq"], "text": ["TL,DR: A source code is a recipe to a cake. The final game is the cake itself. It's far harder to change an ingredient after* baking the cake and finding what ingredients are in a cake given just the cake can be difficult. There are three questions here: 1. What is a source code? 2. Do we as consumers not get the source when we get the game? 3. What is a golden disk (or a master copy) starting at the top: A source code is the actual human-readable code that the developers write and maintain. It is in plain text, often well commented for clarity and well structured for appearance. Given the source code anyone with programming knowledge can change the game, and even release their own version and potentially profit (illegally). Two: While the source code is understandable by humans computers don't know what to do with some letters in a file. What you get on your game disc is compiled, which describes the \"code\" the computer can understand. This sequence of numbers can be understood by the computer, but is just a string of numbers and thus humans usually can't understand or modify it. Even if you use some program (called a decompiler) to turn the byte code back into some human source code it will usually loose all structure, have generated and non-descriptive variable names, and have no comments, making it a pain to read (not mentioning that decompiling a program usually is against the terms of service.) A master disc (a gold disc) is the final version of a games source code, when a game goes gold the source code and executable is printed onto a disc to indicate no further changes are to be made to the game and it is ready for production. This dates back when albums where pressed on a gold vinyl before publishing: all further records would be copied from this gold master record. In summary: this is a source code as we would see it: //this is a comment, This is ignored by the computer. #include < iostream > using namespace std; //This is a program that prints \"hello, world!\" int main(){ cout < < \"Hello, World!\"; //Prints hello world to screen. return 0; //Exit. } While this program might look like this to the computer when compiled. 0x00 0xff 0xaf 0xaf 0x00 0xab 0x14 0x15 0x16 0xab 0xff 0xf3 0x00 ..... you get the idea Which isn't really easy to change. If I wanted the program to also print the name of the user I could add that change into the source in less than 20 seconds. I'd take a lot lot longer to even begin to find where and what bytes to splice into the byte code.", "We dont actually get the source code when buying software in general. The Files distributed are actually just executives protected by DRM, or in common language, software protection. Lets take the starcraft example, The programmers made the source code, the pure code as-is, this is raw code, not protected, nor encrypted, and plainly readable/editable/copyable. If this code would be stolen, the perpetrators could make changes to this code and release it as their own. They could also learn the secrets and mechanics other people have worked hard for and simply just copy or use this in their own project. Now, When a game/software gets released, this source code gets protected, built into executables, DLL's etc. this is obfuscated code and nearly impossible to reverse-engineer without going to great lengths and in best case only achieving limited success. Without these measures there would be stolen software and code everywhere.", "But my question is: why would it be valuable to them NOW? Sure, if he returned it to them years ago before they had to write a new one - holy shit yeah. But now? They already started over and completed the game...so what's the big deal?"], "text_urls": [[], [], []], "score": [37, 5, 3]}}, {"q_id": "69e4ca", "category": "Repost", "title": "- how does antibiotic resistance work?", "title_urls": {"url": []}, "selftext": "I understand antibiotic resistance is a major concern, but if it's random mutations that cause the resistance, wouldn't these happen anyway, making the bacteria resistant without ever coming into contact with the antibiotic ? Or is there something else that allows them to build a resistance, like humans and chillies; if you eat them regularly you can build a resistance.", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dh5u6hu", "dh5u4st", "dh5ui1y", "dh64jns", "dh65cvi", "dh65gi1", "dh5vxh5"], "text": ["So you're taking an antibiotic. It's helps kill bacteria. But in that population of bacteria it kills off the weakest first (the ones without this mutation for resistance). You keep taking the antibiotics and the bacteria keep dying. Except those with the highest resistance. They're still around and now they have the freedom to multiply. So now when they grow and a new population is formed, they're all clones of this highly resistant bacteria forming a population of resistant bacteria", "It's evolution really. Since bacteria replicate so fast, their evolution is way faster. The problem with resistance is not that it exists, but because if you use antibiotics the wrong way, for too little time or for things that don't need it, the few resistant bacteria will survive while the others dont, leaving all the food to the resistant ones, whoch will then become even more resistant and multiply, no longer harmed by antibiotics.", "Your right because it's a random mutation a bacterium could become resistant to an antibiotic even if it never encounters it. But the important question is whether this bacterium will multiply and continue multiplying fast than its dieing. For example if a bacterium becomes resistant to a antibiotic but also become less effective at gathering food as a trade off in an environment where there is non of that antibiotic then that bacteria will likely die off because being resistant to that antibiotic doesn't benefit it in any way and those bacteria that can gather food better than it will reproduce fast taking up more food till there isn't any food left for the antibiotic resistance bacteria. But if it was in an environment where there was that antibiotic then it wouldn't matter that is was worse at gathering food because all the other bacteria would be killed off so they don't have to compete for the food. (Not my area of expertise please correct me if I've got something wrong)", "A very short and non-technical explanation I remember from a microbiology course is this: You killed everything that wasn't resistant to the antibiotic so the ones that were are all that remain to reproduce. You do this enough and nothing will be able to be killed by the antibiotic in question. . . as you've already killed everything that could have been. The whole \"the strong survive\" thing. The people not taking the entire course of antibiotics is a problem too because some of the bacteria aren't COMPLETELY resistant to the antibiotic, but a bit stronger than the rest. If you had taken all your pills they would have died too but since you didn't they get to live and make more bacteria with the same and/or more resistance to that antibiotic. Edit to add: Some microorganisms can also pass their genetic info laterally (like to it's \"sister\" and not exclusively to the \"children\") so the DNA that encodes this resistance can be spread among current generations as well and not limited to offspring.", "So today you have 1 billion bacteria we need to get rid of, so we give you amoxicillin, which we determined is able to kill it. We took a sample so we know for sure. Unfortunately, of the 1 billion bacteria, 1,000 of them randomly got a thicker cell wall. One in a million chance. It didn't show up on the culture because only one in a million have this thick wall. So you take your amoxicillin. And it works great. Let's assume ideal conditions and it killed 100% of the susceptible bacteria. Let's also assume your body is totally incapable of killing the rest. Now you have 1,000 bacteria in your body, 100% of which amoxicillin cannot help you. It grows back. You are back to 1 billion bacteria in your body. Your friend comes in contact with you and gets this new bacterial infection. Now you both need stronger antibiotics. Except, randomly, .0001% of those billion messed up making their sodium pump, and now it expels the new drug... Obviously the mechanisms of defense will be different, the body will play a large role in killing the infections, and the percents won't be as clean, but that is the general idea.", "Everyone else has the \"kill the weak, save the resistant\" side explained, but we havent really explained the \"why wouldnt they just become resistant evem without antibiotics\". Its simply because evolution/natural selection selects for what is better than what came before in a given environment. Without antibiotic flushing, antibiotic resistance just isnt terribly useful, so while its not deleted from the gene pool, its just not going to propagate because it has no discernable benefits.", "> I understand antibiotic resistance is a major concern, but if it's random mutations that cause the resistance, wouldn't these happen anyway, making the bacteria resistant without ever coming into contact with the antibiotic ? Yes, but without the antibiotics in the bacteria's environment there is nothing to promote that mutation over any other, so that resistant bacteria will just be one in billions, insignificant, it will be as likely as all the others to reproduce and survive because there is in their environment it has no advantage, and it's genetics will continue to be insignificant. If the antibiotic is present that bacteria will stand out - survive and reproduce, while the non resistant will die. sooner or later all surviving bacteria will be descendants of that first random mutation that happened to resistant. It's not really that simple actually, resistance isn't black or white. some mutation may give some resistance and multiple mutations over generations may be needed to develop sufficient resistance. If there isn't the antibiotic around all the required mutations would not happen do develop on the same bacteria, so none would be sufficiently resistant."], "text_urls": [[], [], [], [], [], [], []], "score": [13, 7, 6, 4, 4, 3, 3]}}, {"q_id": "69eihe", "category": "Repost", "title": "Why fish meat is vastly different to all meats from land animals", "title_urls": {"url": []}, "selftext": "What I mean is fish is pale and flakes apart whereas most land animal meat doesn't flake and is a lot tougher to eat and cut, what is it that causes this difference as they are both just muscle tissue I thought?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dh62qpa", "dh5x02e", "dh6risj", "dh6ageb", "dh6egb6", "dh6rre0"], "text": ["> fish is pale Most fish is \"white meat\" (even salmon, which is pink because of fish diet, not because it's made of \"dark meat\"). This is because these muscles are used for occasional movements and not for constant swimming. The most common exception is some tuna meat, since tuna are very active swimmers. > and flakes apart The flakes you see are [myomeres]( URL_0 ), bands of muscle tissue in the body that allow the fish to swim with a fishy wiggling motion. Most of the meat you eat from land animals comes from the limb muscles, and isn't segmented like this. You can see the remnants of such segmentation on the body (eg, ab muscles) but even there it's not set up in the same way and doesn't provide the flake.", "There are a few reasons for the difference, the main being the difference in lifestyle. The muscles of a fish are adapted for swimming, whereas muscles of mammals are adapted for moving on land. This means animals need larger, thicker muscles to combat gravity to walk around on land, instead of having natural buoyancy from the ocean. Therefore the muscles are flakier and less dense.", "With regards to colour, mammals have red muscles because of the presence of myoglobin. This protein is absent in the majority of the muscles found in most fish. Myoglobin is an oxygen binding protein that is found in muscles (Similar to hemoglobin in blood). In fish the majority of the muscles (white muscles) are used for bursts of speed and are anaerobic (do not require oxygen). Due to not needing oxygen, an oxygen binding protein is not needed. The grey flesh of the fish near the skin, is the muscles it uses to swim constantly. URL_0", "No one has mentioned gravity in these answers. Fish have a much finer skeleton and different muscle mass mainly because they are supported by the water against the effects of gravity whereas land animals have to fight gravity using their muscles to support themselves in an upright position. Fish muscles are therefore used in a different way. This is why pound for pound, farmed fish add mass far quicker than farmed land animals", "if you've eaten frog, you'll see that their meat is like a cross between fish and land animal meat.", "Nobody has mentioned whale meat, which looks a lot like how beef would look if cows evolved to swim."], "text_urls": [["https://qph.ec.quoracdn.net/main-qimg-b162a317e5b89562d8074cae3c56493f"], [], ["https://www.exploratorium.edu/cooking/meat/INT-what-meat-color.html"], [], [], []], "score": [415, 110, 29, 21, 8, 7]}}, {"q_id": "69eyst", "category": "Repost", "title": "Why can we eat certain food raw (or almost, i.e. steak, sashimi) but not others (chicken, pork)?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dh617qv"], "text": ["It's due to food poisoning (bacteria) and parasite risk. All sashimi-grade fish are flash-frozen to kill off any parasites that may be in the meat. In addition, most sashimi fish are from salt water so it is less likely for the parasites to survive in our non-salt water bodies. Certain fresh water sashimi like mackerel (Saba) have to be pickled beforehand to get rid of fresh water parasites that have an easier time living in our bodies. Steak can be eaten nearly raw because of the large pieces of meat. If you have a large piece of meat, only the outside can be exposed to bacteria. If you cut out the inside, it is generally free from contamination. However, if you ground the entire piece of beef, the grounding mixes the outside with the inside, increasing risk of contamination. Chicken and pork end up carrying a lot more possible food poisoning issues (salmonella and parasites) than beef or sheep. There's also an issue due to the way we raise huge numbers of them and slaughter them which raises the risk of contamination in general (also applies to beef but as stated before, you can get larger cuts of meat from cattle). This is why cooking chicken and pork thoroughly is highly recommended."], "text_urls": [[]], "score": [4]}}, {"q_id": "69f9f0", "category": "Repost", "title": "How does Gerrymandering occur for the borders to be drawn up.", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dh63cw8", "dh67rti"], "text": ["States are allowed to draw up their Congressional lines, meaning they get to decide where the boundaries are for their Congressional districts. These boundaries constantly change because people move within the state and the population of the states change and with that change the number of districts they have to carve out causing a complete rework of the boundaries. Previously the Supreme Court has ruled that states have to *gerrymander* their districts to provide African American/black voters a Congressional district when possible. The idea behind this was that they wanted to increase black representation in Congress. So you're not allowed to draw your Congressional lines in such a way as to reduce the impact of black voters, in fact, you often have to draw them in ways to increase their representation. Now this gets weird, because some states can easily carve up their black populations neatly (or not neatly) into one or two Congressional districts and basically give away that seat to Democrats while reducing their voting block for the surrounding districts and help ensure they remain Republican or give Republicans a better chance at winning them. So if they do that, the courts can rule against them for race based gerrymandering, which is a very contentious issue because the Supreme Court has already mandated that they have to gerrymander in ways that discriminate against non-black/minority voters. So those rulings and legal battles get very interesting where they have a very tight line they have to balance on and intent is typically the deciding factor and needs to be proven the court. Historically, most of the challenges to gerrymandering has been in regards to these race based lines. Either too much preferential treatment towards minorities, or not enough. The Wisconsin case that is going to the Supreme Court is a little more unique because the judges ruled that it isn't a racial thing, it's a party affiliation thing and that they intended to disenfranchise voters of a particular political party. They are saying this violates the 1st and 14th amendment by drawing lines based on presumed party affiliation. If this is confirmed by the Supreme Court we can assume that the minority party in many states will file suit against their state for politically biased districts since essentially every state's majority party who gets to draw the lines does this. And Republicans happen to have the majority in the most states so it could have greater impacts on their ability to hold seats in the House of Reps. It could also have some impacts on the highly influential Congressional Black Caucus who have been reaping the rewards of gerrymandering for some time now. The interesting thing about gerrymandering is that Democrats win the majority of the most gerrymandered districts. But, Republicans are more likely to have drawn those lines. As an example, check out one of the most gerrymandered districts: [NC 12th District]( URL_5 ). This district was drawn in such a convoluted way which gave advantage to a black female Democrat like [Alma Adams]( URL_1 ) to win this seat and she sits as the chair of the NC Legislative Chair of their Black Caucus. Black Americans make up ~20% of NC, but they make up nearly 50% of this district. Is this district highly gerrymandered? YES. Was it illegal or where they just following the guidelines by the Supreme Court to give advantage to black representation? Up to a court to decide. But if this district is redrawn you'd potentially lose Alma Adams, the Black Caucus chair and people would say Republicans were racist for changing it. As you can see this can be hotly debated and quite fascinating in my opinion. Another great example of gerrymandering is the Louisiana 2nd district. This district was purposely gerrymandered to great a \"majority-minority\" district to protect against race based gerrymandering in the 1980s. Ironic, yes, but that's the law and what was done. This seat is occupied by Cedric Richmond. He is the chair of the Congressional Black Caucus for the federal government. If the Supreme Court decides against Wisconsin and Democrats start attacking Republican gerrymandering to their benefit, will Republicans attack districts like Cedric Richmond's which was purposely gerrymandered for race/political biases to get a black politician elected? And if they do, what would be the race relations from such a move? Again, high stakes and tremendously interesting. Some more race based gerrymandered districts: Brenda Lawrence - [Michigan's 14th]( URL_4 ). CBC Secretary. John Conyers - [Michigan's 13th] ( URL_3 ). CBC Member, Dean of House of Reps Elijah Cummings - [Maryland's 7th] ( URL_0 ). CBC. Ranking Member of Congressional Oversight and Reform Committee Sheila Jackson Lee - [Texas 18th] ( URL_2 ). CBC. Thinks Neil Armstrong planted a flag on Mars, complains Hurricane names are too white, thinks the constitution is 400 years old, thinks Congress writes Executive Orders for President Obama, etc.", "There are two types of Gerrymanders: \"Packing\" districts and \"cracking\" districts. For packing, district lines are drawn so that a disproportionate amount of voters from the minority party are in a single district. While this hands that district over to that party, the surrounding districts now have very few members of the minority party, and so will be easily won by the majority party each year. When districts are \"cracked\", lines are redrawn so that, rather than members of one party having a vast majority in one district, they are dispersed across multiple districts. This gives that party a slight majority, enabling them to win congressional seats."], "text_urls": [["https://en.wikipedia.org/wiki/Maryland%27s_7th_congressional_district", "https://en.wikipedia.org/wiki/Alma_Adams", "http://www.texasgopvote.com/images-upload/TX18.JPG", "http://wdet.org/media/daguerre/2016/07/14/aa6b7df6843a25b6bf0d.png", "http://wdet.org/media/daguerre/2016/05/25/53c6d8296e7eeb63f3ad.png", "https://img.washingtonpost.com/wp-apps/imrs.php?src=https://img.washingtonpost.com/blogs/wonkblog/files/2014/05/districts-02.png&amp;w=1484"], []], "score": [5, 3]}}, {"q_id": "69fd5j", "category": "Repost", "title": "Why do CGI use the color green for their background?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dh6473y", "dh640mz"], "text": ["so what these programs do is take any color you want, and remove it from the shot. You can then overlay other things on top of that color. By that definition, you can use any color you want, as long as the live elements of the shot that you do want to keep don't also have that color. Green has the least interference with things like human skin. If you were to use reds/oranges, skin would start to flicker because there's a bit of those colors on skin. Blue was popular in the early days for this, but green seems to be what reacts to skin the least.", "Because green is the farthest color away from any natural hair or skin tone. If you were to use another color, it'd cause really bad clipping. So, using green is the safest bet."], "text_urls": [[], []], "score": [6, 4]}}, {"q_id": "69fd6j", "category": "Repost", "title": "How do batteries work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dh64cof"], "text": ["Electricity, as you may know, is the flow of electrons from one place to another. So in a battery, you put two different metals in there. One of them has extra electrons that it wants to give, the other one is missing electrons and wants to take them. We call this an electrochemical reaction. Electrons flow from the anode (the negative end) over to the cathode (the positive end.) Eventually the anode stops being able to give up electrons, so either the battery is dead and you have to chuck it, or else you have to apply external current to reverse the flow of electrons (in a rechargeable battery)"], "text_urls": [[]], "score": [5]}}, {"q_id": "69fype", "category": "Repost", "title": "Why do MRIs cost so much in the US compared to India", "title_urls": {"url": []}, "selftext": "I recently had a minor ankle injury and the doctor wanted and recommended an MRI. I'm in Ohio and I was quoted $2100 by the hospital to get an MRI on my ankle. I have an HSA so this would have been all out of pocket. I already had a work trip scheduled to India so I waited it out for 2.5 weeks until I got there to find out how much an MRI procedure cost. I was quoted $110, after converting the Indian Rupee to USD, for the MRI. The MRI machine was a Siemens machine and looked fairly new. I went ahead and had the MRI done in India and brought the images back to my doctor in the US and he was able to make a diagnosis and was shocked at the price I paid for the MRI. I know the fee I paid was not subsidized. Can someone please explain to me why the US pays soo much more for the MRI then our Asian counterparts when the results we get are the same?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dh6at4k", "dh6b67n"], "text": ["It's not just asia. Compare US prices to those paid even next door in Canada. This is the same for almost all medical care - in America you pay much more for the same thing. In all 3 of those countries an MRI machine costs a lot of money. In two of those countries that MRI machine will be utilized to the fullest because of market forces; India doesn't have enough rich people to pay inflated rates so they need to recoup the cost in smaller increments, in Canada the government who is paying most medical bills is a strong negotiator so again they must be efficient and productive to make a profit. In the US however you simply have sick people who are in no position to negotiate - the consumers overwhelming desire to continue *living* removes the choice of the free market, creating the conditions for an easy monopoly even among a number of 'competing' entities. In such a position the MRI machine owner has a choice - operate the machine 24 hours a day at $500 per patient, or operate it for 6 hours a day at $2000 per patient. Sure many patients can't afford those rates but since you only need to serve a few to make the same gross (and a higher profit once operating expenses are subtracted) it's actually better to serve fewer patients. Sure that means 3 out of 4 people get no care while the one who does might go into bankruptcy but it means more money in the pocket of the MRI owner.", "1. The US has a culture of lawsuits and so, the cost of these is priced in to the cost of treatment, which India does not. 2. The profit motive is stronger in the US than other countries. I live in Spain now, but used to, until fairly recently, live in the US. My wife was diagnosed with stage 0 breast cancer a few years ago here. Total cost of her treatment was 90 euro (around US$100). I shudder to think how much the treatment would cost in the States. It would be higher even though she has US insurance."], "text_urls": [[], []], "score": [10, 5]}}, {"q_id": "69fzuk", "category": "Repost", "title": "Why do hangovers worsen with age?", "title_urls": {"url": []}, "selftext": "For instance, why are my hangovers worse at age 18 versus 25. I know part of it is just getting old, but it can't be the only reason. I'm very hungover right now.", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dh6a2dh"], "text": ["The biggest factor is your liver. As you age your liver doesn't produce antioxidants as well as it used to, the alcohol stays in your system longer than it used to, and you get more hangovers. Given you seem to have been drinking since you were 18, you've also probably fattened up your liver a bit (alcohol = calories, those calories usually don't get fully utilized = fat in liver), further decreasing how well your liver can cope with bursts of drinking."], "text_urls": [[]], "score": [4]}}, {"q_id": "69gs28", "category": "Repost", "title": "Why haven't we developed an immunity towards the common cold and flu?", "title_urls": {"url": []}, "selftext": "I mean most people will get either one or both every year...why haven't we as species developed an immunity against it until now? Wouldn't our bodies know how to fight it the moment we get it? Edit: if it mutates all the time how are medications working? How would they be able to fight different mutations..known and unknown and our bodies cannot? Edit: does it mean then that if I am already sick and wash my teeth on theory I shouldn't get sick again for reusing the same toothbrush as I should have developed an imunity to this strain? Why do we have to change toothbrushesh after being sick then?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dh6g32y"], "text": ["The problem with the flu is that it is one of the diseases that mutate the most, it may be very simple, but it mutates so often that as the body develops resistance, the flu is already changing to infect another human in a different way :)"], "text_urls": [[]], "score": [3]}}, {"q_id": "69gwum", "category": "Repost", "title": "What is a source code?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dh6hjl1", "dh6h3pf"], "text": ["Programmers create code by typing in instructions such as [this]( URL_1 ), and that is the \"source code.\" The processor chip on your computer doesn't understand that; processors only understand 1's and 0's, so after the \"source code\" is typed, they apply a program called a \"compiler\" to translate the words and human-readable instructions that you see in the source code into 1's and 0's that the processor understands. So when you get the installation disk for a program, say Microsoft Office, if you look at the files that are included in the disk, you'll only see the binary executable files that the computer understands. The disk doesn't have any of the source code. And because the disk doesn't have any of the source code, you can't read through to check if Microsoft has put instructions in their Office program to steal all your data. Companies usually don't give out the source code for their programs and apps, because it's proprietary and they don't want the competition to steal their coding ideas and make a better program. However, some programmers and some companies do provide the source code; this is called \"[open source]( URL_0 )\" (as in, anyone can open and read it if they want to), and it's usually done to show that there are not hidden tricks in the code.", "Computer programs are constructed of sequences of binary values that, when run through computer circuits, perform various logical operations. Obviously this would be extremely difficult to write by hand when making more complex programs such as games, so to try to make things more friendly \"programming languages\" were developed. These languages allow logical sequences to be constructed with human-friendly terms and then to be \"compiled\" into the actual binary code of the program by a specialized program. \"Source code\" is the human-friendly language for the program before it is compiled. Once it is compiled it is a hopelessly dense and confusing mess, but the source code is easy to read, understand, and change."], "text_urls": [["https://en.wikipedia.org/wiki/Open-source_software", "http://i1-news.softpedia-static.com/images/news2/Keep-Your-Programming-Code-Safe-Obfuscate-It-480832-2.jpg"], []], "score": [10, 3]}}, {"q_id": "69iez6", "category": "Repost", "title": "What material form is fire? is it solid, liquid or gas?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dh6tzz2"], "text": ["Except for very hot fires (which can be ionized (charged) enough to become plasma), fire is just very hot gas being created by the process of combustion, and moving up rapidly and cooling because it's far more buoyant compared to the much cooler air around it. The light is \"blackbody radiation\", which in simple terms is the same reason stoves glow red-hot, or metal glows when it's heated, or stars shine as they undergo nuclear reactions. The reaction of burning creates heat, and being hot gives off light. Our own body heat gives off this same light, actually, except it's at a lower wavelength than visible light, and this is what infrared cameras see."], "text_urls": [[]], "score": [4]}}, {"q_id": "69isdt", "category": "Repost", "title": "Why is Africa so underdeveloped and has not kept up with the rest of the world?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dh6wqcv"], "text": ["It's catching up now pretty quickly. The reason they're underdeveloped on average is because they got screwed by Europe and weren't allowed to develop the proper way due to that. Once they finish recovering it's fine. You see similar patterns in several other regions too."], "text_urls": [[]], "score": [3]}}, {"q_id": "69jr26", "category": "Repost", "title": "What are the differences between communism and socialism?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dh75q7y", "dh75aww"], "text": ["Socialism is when the government owns or regulates parts of society that could be a privately owned businesses. For example, the police, firefighters, roads, post office, public schools, public parks, and military are all examples of socialism. Some may say that socialism is the opposite of capitalism, but socialist systems and capitalist systems (privately owned businesses) usually go hand-in-hand. Every modern government uses a combination of both. Communism doesn't really fit in the socialist/capitalist model. The idea of communism is that you don't have to have private owners, or governments, deciding who owns what. Instead, society divides everything up based on who needs stuff, and everyone works as hard as they can to make everyone more stuff. It has sort of worked on very small scales, like in hunter-gatherer tribe or in little communes (hence the name.) Some may say that communism is a more extreme version of socialism, but this is not the goal of communism. In the past, when people tried to build communism, it didn't work, and the government devolved into totalitarian socialism. This gave people the idea that communism *is* totalitarian socialism. But this is kind of like saying \"anarchy is people killing you for your shoes.\" That's certainly one possible outcome of anarchy, but that's not the outcome anarchists are trying to achieve.", "Communism is effectively a more extreme version of socialism. On paper (as in practice many socialist and basically ALL communist governments we've had throughout history were anything but!): * Basic Idea Under Communism, classes make no sense. Even top country leaders should be seen as nothing more than workers, and should have no more privileges or wealth than the lowliest cashier (truth be told cashiers deal with some seriously f**ked up sh*t though). Under Socialism Everyone should have access to the methods and means by which they can self-actualize, but how far you go remains mostly up to you. Nevertheless, the profits and returns from innovation and industry SHOULD benefit society as a whole. Most property is common, but small parts beyond the minimum can then be split off and owned by individuals once the needs of the population have been met. * Profit Under socialism, profit should be redistributed in accordance with the value of your work. Everyone benefits, but someone whose work was more important gets more. A goalie would be paid more than the right defender. The head programmer for a piece of software would be paid more than one of the ten marketing guys. Under Communism the profits are 'removed' and turned into more stuff. You get the prestige and glory of your position, but the janitor can have the same nice couch and widescreen TVs as the project manager. Any advances in production technology in particular are to be used to up *everybody*'s quality of life as soon as possible. * What did that mean? who owns what? Communism: Nobody. Technically everything including your shirt is just assigned to you as the user - often 'permanent' user. You need a house you get a house. You need a car you get a car. But when you die, your car does not become your son's second car: he needed a car he *got* a car. Your car is going to someone else who's about to need a car. Because it wasn't yours, it was everyone's. But if you needed something, you got it. Socialism: Individual luxuries and items are the individual's. That's your shirt. That's your bicycle. That's your glasses. That's your house. But any means of production or infrastructure, those are the state's to control, for everyone. The appartment building, the factory, the hospital, the school; all of those are \"everybody's\" and to be run as such. You don't get to own factory workers. You don't get to lord massive profits over them. But you CAN use the money you make for your hard work to buy yourself a nice dinner or a new watch. * Just one last thing: To be very clear, while we have had governments call themselves communist, not once in human history have we ACTUALLY had an ACTUAL communist country. North Korea's calling itself a Democracy too, after all. I think Star Trek's Federation is one, or somewhere in between Socialism and actual Communism depending on how you view the fact that when you die they'll probably just chuck everything into a replicator and turn it into other people's stuff."], "text_urls": [[], []], "score": [4, 4]}}, {"q_id": "69kh26", "category": "Repost", "title": "if video can be measured in frames per second, is there an equivalent unit for audio?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dh7a4kl", "dh7i3aj", "dh7a17r"], "text": ["Yes, it's samples per second aka the sampling rate of an audio signal. When you convert analog sound to a digital format it is done by sampling the analog wave thousands of times a second to convert it into a number like a voltage. The higher the sampling rate, the greater the frequency in hz that can be represented. It ends up needing about twice the sampling rate, to correctly sample a specific frequency of sound. For instance if you need to record a 20,000hz analog soundwave, you need to sample it at 40,000 times a second or 44.1khz which is what music on a CD is sampled at. The other factor is the size of each sample which effects how many levels of sound it can encode for each sample. This is analogous to how many colors an image has. An 8 bit sample allows for 0-255 levels of sound, or 256 colors if it were photographic data. Where as a 16 bit sample allows for 0-65,355 levels or voltages, or 65,356 colors if it were an image. So a 16 bit 44.1khz wave file encodes 65,356 discrete \"loudness\" or voltages in each sample and it samples (or does it) 44,100 times a second.", "Several people have mentioned that the sampling rate of a digital audio signal needs to be at least twice the highest frequency you want to accurately capture. This is called the Nyquist limit, and [I whipped up a quick graphic to explain why here.]( URL_0 ) The gist is that to produce a faithful representation of a continuous periodic function using finitely many data points, you need to have at least two points present in every period, or you won't have enough information to recreate the original signal. Real audio signals have many component frequencies, not just one like the pure tone in those images, so you need to decide what the maximum frequency you want to capture is, and then sample at least twice that often. For most people, human hearing really drops off past 20-25 kHz, so sampling at 40-50 kHz will sound good, hence the CD audio standard of 44.1 kHz.", "For digital audio there is the sample rate. Audio is recorded in digital form by taking the amplitude of the sound wave at regular intervals. CD quality audio does this at 44.1kHz, in other words 44100 times a second."], "text_urls": [[], ["http://imgur.com/a/PcWxd"], []], "score": [156, 6, 4]}}, {"q_id": "69l9nd", "category": "Repost", "title": "How does the Higgs field impart mass?", "title_urls": {"url": []}, "selftext": "Sean Carrol uses the analogy of a crowded party where a physicist and Angelina Jolie show up and both try to get to the bar. Angelina finds it difficult to cross the room because everyone wants to meet her. She has much mass. The physicist has little trouble getting to the bar. He's a lightweight. The Higgs field he describes as something like molasses and particles with an affinity for the Higgs field get stuck in it and this appears to us as \"mass\". OK, this analogy has some rather serious flaws: For example, Newton's laws: *an object in motion remains in motion* (Even a heavy object does not stop once it is set in motion in space, especially a heavy object.) High mass only resists acceleration, not motion itself. The two analogies above treat the Higgs field like some kind of friction force. Moreover, mass generates gravity. The more massive the particle, the more gravity it puts out. So is the Higgs mechanism intimately tied to gravity? So a better layman's explanation is needed ... How does the Higgs field impart the quality of \"mass\" to other particles?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dh7h01u"], "text": ["Okay, so the way he describes mass is meant for people who don't care about the little details. The Higgs field makes it harder for particles to *accelerate*, not just slow them, which is where your understanding is correct. The analogy can't be really good because there's not much intuition behind anything quantum. As far as gravity goes, it turns out that gravity isn't based on mass, but on energy and momentum, the former of which can be intuitively derived from E = mc^2 and the latter can be intuitively derived from the actual equation Einstein gave, which takes into account relativity: E^2 = (p c)^2 + (m c^2 )^2 . So, the Higgs field links energy and momentum to mass. Edit: Whoops, forgot to mention, E is energy, m is mass, c is the \"speed of light\" constant, and p is momentum, which can be calculated with p = gamma m_0 v where m_0 is the resting mass, v is the velocity, and gamma is the Lorentz factor as given by gamma = 1/sqrt(1 - v^2 / c^2 ) where v and c are the same as above, velocity and \"speed of light\" respectively."], "text_urls": [[]], "score": [7]}}, {"q_id": "69n62k", "category": "Repost", "title": "Why are toilet seats shaped like '0' at home and 'C' in public restrooms?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dh7uug4", "dh7zho5", "dh7yllz", "dh7uu36", "dh80p2n"], "text": ["The cut out in the C shaped toilet seats is right where genitalia would touch if it was O shaped. The cut out prevents people from smearing their dirty crotch on the seat and transferring grossness to the next person. The cut out is NOT for males to try to pee in between.", "Contrary to the top comment, the space is definitely there to counteract drops of urine. Since that is the area where urine most commonly drops while the person urinating is finishing it makes perfect sense for there to be no seat there thus eliminating the need for a person sitting down on the toilet to have to wipe up another person's urine.", "[Uniform Plumbing Code]( URL_0 ) > \u201cWater closet seats shall be properly sized for the water closet bowl type, and shall be of smooth, non-absorbent material. Seats, for public use, shall be of the elongated type and either of the open front type or have an automatic seat cover dispenser.\u201d", "Public restrooms are usually more industrially designed to allow a lot of people to do their business while making as easily clean-uppable a mess as possible. So unless the place is posh, they don't use toilet lids and the seats are C-shaped. Intent is for you to get your stuff done and get out, without making extra work for cleaning staff. Plus, one less thing to bang and break and have to replace. Home washroom toilets are designed with lids for a number of reasons: appeal, because they generally get a lot less traffic so there's not as much cleaning and wear-and-tear, and because you don't want to drop stuff that you use and store in your (usually smaller) bathroom in them accidentally.", "I have done some research and the best I can come up with is the open c shape got adopted as code in many municipalities and the trend just continued to today. The c shaped seat doesn't seem to have any real commercial advantage and some even say they are a less robust design for a commercial use. Could be a case of, well that's just how we've always done it. Shoulder shrug."], "text_urls": [[], [], ["http://epubs.iapmo.org/UPC/mobile/index.html"], [], []], "score": [107, 28, 16, 12, 3]}}, {"q_id": "69q9zy", "category": "Repost", "title": "Why water spirals down the plug hole, and why it is spirals the other way in the opposite hemisphere", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dh8k1o1"], "text": ["It doesn't spiral the other way in the opposite hemisphere... That's a misconception. It just spirals whatever way it wants depending on how the water flows into the drain and other external factors etc. The rotation of the earth/gravity isn't strong enough for it to affect the direction water spirals into a drain."], "text_urls": [[]], "score": [8]}}, {"q_id": "69u69k", "category": "Repost", "title": "why is removing your flash drive from the computer harmful and how does hitting eject on your computer make it safe to remove it?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dh9dnbg"], "text": ["When your flash drive is plugged in/mounted, your computer is accessing the files. When you hit the eject button, that is telling your computer to put everything back where it found it because you're about to remove the device. If you just pulled it out, there is a chance that your computer was modifying a file on it that could now be corrupted."], "text_urls": [[]], "score": [3]}}, {"q_id": "69uuhm", "category": "Repost", "title": "Why are we not boiling thousands of gallons of seawater and collecting the steam?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dh9jeiq"], "text": ["The energy required to boil that much water would be pretty immense, and would leave a lot of salt residue behind. And, I mean, why would we?"], "text_urls": [[]], "score": [3]}}, {"q_id": "69vq99", "category": "Repost", "title": "Why do FM radio stations only end in odd numbers?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dh9qxj1"], "text": ["Radio station frequencies that have a .1 MHz difference would interfere with each other if they were in range of each other. Generally a difference of .2 MHz or greater is ideal so to reduce any interference."], "text_urls": [[]], "score": [3]}}, {"q_id": "69xkhb", "category": "Repost", "title": "why do you get goosebumps when you hear someone sing well?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dha6vi8", "dha3i5n"], "text": ["The answer is we are not sure and there are many theories Goose bumps start in the part of the body called the sympathetic nervous system. The sympathetic nervous system sends signals from your brain to your skin. Goose bumps usually happen when you get cold or feel certain powerful emotions, such as fear. When you feel certain powerful emotions, a part of your brain called the hypothalamus sends a message via your nerves to the muscles in your skin to tighten up. When the skin on your body gets tight, your hairs stand on end and goose bumps form. **You're probably still wondering exactly how goose bumps are related to music.** As you may have experienced before, goose bumps can occur when you hear a love song, a classic song, or a passionate version of the Star Spangled Banner. A theory about why people get goose bumps from music is that People can feel intense emotions, like sadness and passion. When people feel strong emotions, their brains release the same chemicals that tell the skin to form goose bumps. *More details for nerd 5 year old -* About 50 percent of people get chills when listening to music. [Research shows]( URL_3 ) that\u2019s because music stimulates an ancient reward pathway in the brain, encouraging dopamine to flood the striatum\u2014a part of the forebrain activated by addiction, reward, and motivation. Music, it seems, may affect our brains the same way that sex, gambling, and potato chips do. Strangely, those dopamine levels can peak several seconds before the song\u2019s special moment. That\u2019s because your brain is a good listener\u2014it\u2019s constantly predicting what\u2019s going to happen next. (Evolutionarily speaking, it\u2019s a handy habit to have. Making good predictions is essential for survival.) But music is tricky. It can be unpredictable, teasing our brains and keeping those dopamine triggers guessing. And that\u2019s where the chills may come in. Because when you finally hear that long awaited chord, the striatum sighs with dopamine-soaked satisfaction and\u2014BAM\u2014you get the chills. The greater the build-up, the greater the chill. You can feel chills from any genre, whether it\u2019s Mozart, Madonna, tango, or techno. It\u2019s the structure\u2014not the style\u2014that counts. Goosebumps most often occur when something unexpected happens: A new instrument enters, the form shifts, the volume suddenly dims. It\u2019s all about the element of surprise. **But there are competing theories.** Neuroscientist [Jaak Panksepp]( URL_0 ), for example, discovered that sad music triggers chills more often than happy music. He argues that a melancholy tune activates an ancient, chill-inducing mechanism\u2014a distress response our ancestors felt when separated from family. When a ballad makes us feel nostalgic or wistful, that evolutionary design kicks into gear. __________________________________________________________________________________________ Source 1 - URL_1 Source 2 - URL_2", "It's depends on the person, but I recently read a study about people who get intensely pleasurable experiences, like \"chills\", from listening to music. They noted that when this happened, the same parts of the brain are active that 'rewards' itself by releasing dopamine from things such as sex, eating, and even opiates. [Here]( URL_0 ) is a link to that study, for the curious."], "text_urls": [["http://www.sensoryresearch.net/misc/EmotionalSourcesOfChillsInducedByMusic.pdf", "http://wonderopolis.org/wonder/why-do-you-get-goose-bumps-when-someone-sings-beautifully", "http://mentalfloss.com/article/51745/why-does-music-give-us-chills", "http://www.nature.com/neuro/journal/v14/n2/abs/nn.2726.html"], ["http://www.pnas.org/content/98/20/11818.full"]], "score": [149, 23]}}, {"q_id": "69xlgb", "category": "Repost", "title": "Why do game companies charge the same for a digital download as they would for a hard copy?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dha3kdj"], "text": ["Because that's what the market will accept a game is worth. Cost of shipping is a very negligible part of the cost, printing a disc costs a few cents and the middle man won't impact the cost of a single copy to a significant degree. Most of the cost is from the actual costs of development. Even if we assume there is a significant difference the market is willing to pay the same price for a game. As soon as the market decides it isn't worth the cost the prices will start to drop."], "text_urls": [[]], "score": [4]}}, {"q_id": "69ya0b", "category": "Repost", "title": "How do carrier pigeons/ravens know where to go?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dha8ih0"], "text": ["they don't go elsewhere. they only go home. if you wanted to send a message to city A, you have to have a pigeon that was homed in city A. if you wanted to send a message to city B, you have a pigeon that grew up in city B. once you send that message over. then you have to send a messenger by horse to bring you another pigeon from that location to where you are."], "text_urls": [[]], "score": [13]}}, {"q_id": "69yf86", "category": "Repost", "title": "How does the weight exit your body when you're losing weight?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dha9ntm", "dha9nz1", "dha9pb2", "dha9ool", "dhalgy0"], "text": ["The vast majority of fat is lost through breathing. Since fat is stored as long hydrocarbon chains, the body can break it down for energy, then the leftover bits are carbon which is shuttled to the lungs where you breath it out as carbon dioxide.", "Awesome question: you breathe it out! This has actually been known since at least the 1950's. In part, you will lose a small amount in urine, fecal matter, sweat and so on - but mostly it is breathed out in the form of carbon dioxide.", "It gets converted into water and CO2. The CO2 is carried into your bloodstream and is exhaled out the lungs, and you sweat or pee out the water.", "Some of it leaves in your breath. You breathe in oxygen and exhale carbon dioxide. Other amounts leave your body as other waste material, urine and poop, or as sweat.", "The vast majority of the weight leaves your body by breathing--specifically, exhaling CO2. But please don't take this to mean that the way you're going to lose weight is by hyperventilating. Exhaling is just the mechanism for your body to physically lose those carbon atoms, you still need to exercise to make your body burn the fuel in your body first."], "text_urls": [[], [], [], [], []], "score": [57, 15, 14, 14, 4]}}, {"q_id": "69ytru", "category": "Repost", "title": "How is time the 4th dimension?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhadpf4"], "text": ["There are different types of dimensions, spatial and temporal. We live in three spatial dimensions and one temporal dimension. And time doesn't \"exist in first-third dimensions\" quite like you describe it. Think of dimensions like coordinates; how much information do you need to precisely describe any point in the universe? If the universe were 1-dimensional (like a ruler) you'd need only a single piece of information\u2014length\u2014to pinpoint any location. All points would be just a different amount of distance away from one end of the ruler. In a 2D universe, like a map, you would also need width. Both longitude and latitude are necessary to know your exact location on a map. And in a 3D universe, you also need to know depth. If you stand on a globe, height is important because otherwise you could be underground or in orbit. Those are the three spatial dimensions, xyz. However, in our 4D universe, we also need to know _when_. Any point or event occurs at a specific time, which is why people often talk about spacetime as a combination of the four dimensions. Often just dealing with what and where is not enough, but you also have to take into account when and for how long. When people talk about fourth dimension being unfathomable, they usually refer to a hypothetical fourth _spatial_ dimension. Likewise, a second _temporal_ dimension would be utterly alien to us. What would it even mean if time had that sort of \"width?\""], "text_urls": [[]], "score": [5]}}, {"q_id": "69zn5q", "category": "Repost", "title": "If there is no mechanical storage to read or write on, where and how is data stored on SSD?", "title_urls": {"url": []}, "selftext": "There are players that claim that there is no movement of mechanical parts in SSDs, and that leads to better performance (?) Energy efficiency And less heat. If this is true, then how is the data stored?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhaklhh", "dhajmry"], "text": ["Just imagine a giant prison, billions of rows deep, wide, and maybe 64 stories tall. In SLC, the good fast kind, if there are three electrons in the cell it it is a zero. If there are five electrons, it is a one. Then you just use two conductors (prison guards) to measure the charge inside to get the value, and to change the value you let every electron in a given prison block (512 byte cluster) out into the yard (cache) and then put them back in with the desired number of electrons (lockdown). After you write enough times to one cell, the door hinge breaks and that cell is retired. Extra unused cells are held in reserve for this eventuality, Enterprise drives with less capacity are just reserving more cells because they expect more writes. In tightly packed TLC prisons, a third value of seven electrons can be used to finagle some extra info out of the same cell, increasing density.", "> If this is true, then how is the data stored? It is true. The data is stored in solid-state chips which use semiconductor switches to direct electrons into insulated \"cells\" that will trap the charge and store it long-term. This allows binary data to be encoded in a very small space and be retrieved without any mechanical movement."], "text_urls": [[], []], "score": [5, 3]}}, {"q_id": "6a4nnj", "category": "Repost", "title": "Why do specific words start to sound foreign to us after hearing/seeing them too many times?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhboa8a"], "text": ["It's a phenomenon called [semantic satiation]( URL_0 ) in which repetition causes a word or phrase to temporarily lose meaning for the listener, who then perceives the speech as repeated meaningless sounds."], "text_urls": [["https://en.wikipedia.org/wiki/Semantic_satiation"]], "score": [3]}}, {"q_id": "6a5tph", "category": "Repost", "title": "Diplomats diplomatic immunity and why are they considered \"above the law\"?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhbwarj", "dhbwo22"], "text": ["Basically it's to protect them from political retribution from their host country. Imagine a diplomat to a dictatorship. Every time that dictator was mad at that diplomat's country, he could invent some bullshit crime to imprison/execute the diplomat. With the existence of diplomatic immunity countries lose any reasonable pretext to imprison diplomats, meaning that if they do so anyway it pretty much can only be interpreted as an act of war. Now, countries can expel diplomats that they don't like/want and the country of origin for a diplomat can still prosecute them for any crimes they have committed, so it's not like they're totally exempt from the consequences of their actions.", "basically they have immunity from being prosecuted by the host country, this doesn't make them above the law. In the event they commit a crime the host country will inform the home country and the home country will decide to either take the diplomat home for punishment, allow the host country to punish them, or take the diplomat home and not punish them. This is useful because it deters nations from making absurd laws only to punish the diplomat and the concept is protected by the Vienna conventions on diplomatic immunity and if broken would open the host country up to a whole host of issues with other countries possibly no longer respecting their diplomatic immunity."], "text_urls": [[], []], "score": [5, 3]}}, {"q_id": "6aakgs", "category": "Repost", "title": "In music, why do we perceive minor keys as sounding sad?", "title_urls": {"url": []}, "selftext": "I've noticed that writing in any minor key (Cm, Fm, and Gm being especially harsh) evoke emotions of sadness, loneliness, and depression. While this may not be the case the entire time, it seems to be that way most of the time. Why is it, that as humans, we perceive the minor keys as sounding \"sad\" or not happy? Obviously, there are not very many happy songs that are centered around a minor key, so why is it that they are used to evoke these emotions? Does it involve the way we process the sound, or is it because our ears were trained since birth to associate intervals with sadness?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhd7za1", "dhdgycf"], "text": ["ELI5 answer: It sounds like sad voices. More detailed answer: Research into this shows that it is not purely cultural. Scientists have played Western music to tribes who have never heard major or minor scales and identified minor as being sad and melancholy by comparison. Further research shows that the minor key mimics the tones we use when we sob, cry, moan, wail, and groan. > We reveal that the minor third also occurs in the pitch contour of speech conveying sadness. Bisyllabic speech samples conveying four emotions were recorded by 9 actresses. Acoustic analyses revealed that the relationship between the 2 salient pitches of the sad speech samples tended to approximate a minor third. Sad voice study: URL_0 Tribe study: URL_1", "If your interest has been piqued, Oliver Sachs wrote a great book relating to all this called 'Musicophilia'. It can be a little heavy at times, but for the most part, it's a simple and engaging read."], "text_urls": [["http://ase.tufts.edu/psychology/music-cognition/pdfs/Curtis&amp;Bharucha2010Emotion.pdf", "http://www.sciencedirect.com/science/article/pii/S0960982209008136"], []], "score": [32, 7]}}, {"q_id": "6aaw13", "category": "Repost", "title": "Why do you get startled/feel a rush of a adrenaline if you catch yourself falling asleep?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhd3udp"], "text": ["Are you talking about hypnic jerk (sometimes called hypnagogic jerk)? That feeling where you jerk suddenly back awake sometimes when you're falling asleep? The prevailing theory is this is an evolutionary holdover from our earlier primate days, and is a danger response so our ancestors didn't accidentally fall out of trees."], "text_urls": [[]], "score": [5]}}, {"q_id": "6aazvy", "category": "Repost", "title": "How do EMPs work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhd5jkp", "dhdau4y"], "text": ["Electricity and magnetism have a direct relationship. A magnetic field induces an electrical field and vice versa. For instance this is how turbines work. Magnets spin around a conductor, and the electrical field they induce gets pumped through wires allllll the way to the device you're using to get onto Reddit. Now imagine you exploded a GIANT magnet, in the sky. The field it emits will be conducted by anything...well anything conductive. In practical application this would take the form of an air burst nuclear device. The thing is, electrical fields, and magnetic fields are actually types of minor radiation. As part of the nuclear device's huge destructive instantaneous decay, and all of the dangerous ionizing radiation it gives off, you also get a massive amount of electromagnetic radiation. That's your EMP. Now you might ask \"how does that actually screw with my electronics?\" Well, you're talking about integrated circuits with lots of semiconductors, transistors, capacitors, etc etc... they're only able to handle so much current and voltage. So when antennas, power lines, or wiring get hit with this massive EMP, they conduct the fields into electricity which can overload the circuits. How can you protect stuff from an EMP? Good question. Your answer is something called a Faraday cage. Basically, you create a conductive envelope which effectively insulates the material inside from the outside environment, as electricity will simply flow through the cage and thus around the object.", "An EMP is a massive burst of radio waves. In a similar way to how an explosion shockwave is a sudden burst of sound. The effects of an EMP are to induce an electrical current in anything conductive in the area. This results in electronics frying as huge voltages suddenly appear in the middle of circuits, where they are not supposed to be. Large metal objects will heat up significantly due to the current. There are many ways to create an EMP, a large radio antenna attached to a magnet and some explosives is one, the other common way is a nuclear bomb in the upper-atmosphere. The nuclear bomb generates an EMP by ionising the air, kicking out lots of very fast-moving electrons. These electons zoom through the Earth's magnetic field, causing them to bend their path. A moving charged particle changing direction causes radio waves to be emitted. A nuclear bomb detonated in deep space would not cause an EMP, it is the Earth's magnetic field and the ionised electrons from the air which cause it!"], "text_urls": [[], []], "score": [7, 3]}}, {"q_id": "6abeh6", "category": "Repost", "title": "How are we able to detect hundreds of incredibly distant exo-planets that are lightyears away from us, but we are still unsure if there really is a ninth planet orbiting our sun?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhdagot", "dhd7dac", "dhd8tes", "dhd8033"], "text": ["It's nighttime. Here, have a telescope. See that building way over there? You can pick out details in the rooms that are lit, maybe even see people, what they're doing, etc. Now using the telescope, in your own dark room, find your car keys.", "Because the ninth planet, if it exists, doesn't end up between its star (our sun) and us. The data we have on exoplanets typically comes from them moving in front of their star and dimming its light in specific ways. This means they have to be orbiting in a way that allows us to notice this dimming. The ninth planet wouldn't do this for us.", "We gave several exoplanet detection methods, but the main ones boil down to \"a planet coming in front of a star makes it dimmer\" and \"the gravity of a planet orbiting a star makes it wobble, in different directions depending on where the planet is in its orbit\". Both methods are biased towards planets close to their star, and to a lesser extent large planets. It's very hard to detect planets far from their star, as they don't affect it very much. Any undiscovered planets in our solar system are dozens of times further from the Sun than Earth is, and are almost certainly much smaller than Earth too. There's one other issue. A \"planet\" has to meet some criteria that dwarf planets don't. Detected exoplanets are usually large enough we can be confident they'll meet such criteria, although perhaps some won't. It's not so clear whether any undiscovered objects in our solar system will qualify as true planets. We actually have quite a few dwarf planets, perhaps too many to definitively count; but there's no guarantee any true planets remain.", "Imagine your sitting on the 50 yard line of a pitch black football stadium. A ninth planet would be the equivalent of a golf ball on the 40 yard line. Sure it's close to you, but it's still black on black. A exoplanet that we can see would be the equivalent to a golf ball in the end zone. The only difference is that there is also a flashlight in the endzone (the star that is orbiting). Every now and then you will see the object in the endzone because there is enough change in light to detect them regardless of distance."], "text_urls": [[], [], [], []], "score": [25, 9, 5, 4]}}, {"q_id": "6ace50", "category": "Repost", "title": "Why do we get bags under our eyes?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhdgfw8"], "text": ["There are multiple reasons - **Aging** With the aging process, the ligaments underneath your eyes that hold back fatty tissue begin to weaken, and the tissue can fall forward to form under eye bags. **Tiredness or Sleepy Eyes** Fluid accumulates into the skin under the eyes as gravity drags it downward whilst you are upright. So when you lay down to sleep the fluid is able to drain away into the nasal passages. There are drains that connect the nose and eyes and allow that fluid to move back and forth between wake and sleeps cycles. If you notice that you have bags under your eyes early in the morning but they're generally gone by noon, it probably means they're being caused by fluid retention. You might be able to reduce their appearance by simply using an extra pillow to elevate your head while you sleep. **Heredity** One of the biggest reasons people get bags under their eyes is because their parents have them. It's in your genes, and -- aside from plastic surgery -- there's not much that can be done about it. Some other reasons - - Sinus infections can cause them as well, by constantly stretching the skin beneath your eyes. - Swelling (adema) or other infections."], "text_urls": [[]], "score": [3]}}, {"q_id": "6ad7jc", "category": "Repost", "title": "Why do people in cars have to wear seat belts, but people on buses can just stand around in the aisle?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhdkc38"], "text": ["Several reasons, but the main one is because historically there are so few fatalities on board buses that transport regulation organizations don't think its necessary. (Most injuries and fatalities related to buses come from pedestrians or other cars being hit by them, not being inside of them.) Buses are much more massive than the average car, so in an accident they probably wont deflect as far in an accident. This means passengers would likely suffer less from an impact than if they were in a hatchback. Bus drivers are well trained and know how to drive defensively, making sure the vehicle is kept safe. Another factor is belts would be inconvenient for bus users to have to put on and remove frequently. Passengers with large loads like groceries would find it awkward, and might slow down the getting on/getting off part, and bus drivers need that precious time to stay on schedule for their route. The belts would also require inspection and maintenance, because unlike regular car safety belts, their service life would be much harsher, even compared to safety belts on military transports. An average commuter would only be buckled in for a few minutes, and might not use the belt correctly. This means the belts and buckles would wear out faster, meaning more breakdowns on the belts and buckles, and replacements. Which is expensive. Lastly, there's no way to enforce people wearing them. If some kids decide they don't want to wear them even if they were present, the bus driver can't force them because he has driving to do."], "text_urls": [[]], "score": [3]}}, {"q_id": "6adfg6", "category": "Repost", "title": "How do nature documentaries get so close to dangerous animals and also get several angles without affecting their natural behavior?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhdlsxf"], "text": ["They zoom in and stay onsite for days to get a bunch of varying footage and patch it all together later (pretty seemlessly) and also add their own sound effects."], "text_urls": [[]], "score": [3]}}, {"q_id": "6ajho6", "category": "Repost", "title": "What was the cause of the American Civil War?", "title_urls": {"url": []}, "selftext": "I would like to point out first of all that I am from the UK, where we are not taught ANYTHING about the subject. I have been interested in the Civil war from some time, and I am currently dating a girl from Arkansas. Everyone has been pretty biased on one side or another, so I am looking for an unbiased description of the events / cause of the American Civil War. Thank you for reading and for your time.", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhezn2l", "dhf47lw", "dhf052h"], "text": ["Slavery. A bit of background: There was tension between slave and free states since the revolutionary war (and before really). There was a balance of power between the two groups in the senate since there was an equal balance of free and slave states so neither side could dominate. As new states were admitted, there was a lot of jockeying to decide if this would be a free or a slave state which would give one side or the other more power and upset the status quo. The solution to this was the Missouri compromise. This meant that states would be admitted basically two at a time, one free and one slave state. Sometimes this meant cutting prospective states in two to achieve the desired result. This compromise broke down in 1854 which also destroyed one of the major parties of the time: the whigs. From the ashes of the whigs arose the GOP, the republicans. The GOP were a strongly anti-slavery party and in 1860 this fledging party won the presidential election giving the world Abraham Lincoln. The support for the GOP was almost exclusively in the northern free states and it had almost no presence in the southern slave states. The issue of slavery was critical to the 1860 election. It was the dominating issue of the time: would slavery continue? Lincoln was aggressively anti-slavery and so the southern states split off to make their own confederacy and then in 1861 you have the civil war. So slavery was absolutely central to the civil war. Sometimes this is framed as \"states rights\" - what should be the balance of power between the federal government and the states, but this turn of phrase hides the fact that it was a *states right to have slaves* that was at issue.", "Slavery, State's rights(to have slaves), and cultural differences. Slavery composed a key part of the southern economy, famously in cotton and other crops. The abolitionist movement had been gaining power in the north for decades, and the election of anti slavery president Abraham Lincoln made the southerners fearful that he would abolish it, which would be disastrous to their economy. On the states rights side, like I said, a lot of it was about the state's rights to maintain slavery. However, the south had been less inclined to participate and accept the federal government for a long time before that. One significant event was the nullification crisis, wherein South Carolina refused to accept, or \"nullified\" federal tariffs, claiming that states had the right to nullify federal laws. This, of course, would shatter the federal governments authority, so the president eventually resolved it. But the south has always been smaller in population, giving it a disadvantage in government. TLDR: Slavery, state rights(to own slaves), as well as longstanding refusal to accept federal power and dislike of perceived control by the north.", "For an in depth answer, check out this [wonderful post]( URL_0 ) in r/AskHistorians."], "text_urls": [[], [], ["https://www.reddit.com/r/AskHistorians/comments/68myvr/why_was_there_a_civil_war_why_could_that_one_not/"]], "score": [8, 4, 3]}}, {"q_id": "6ajyw5", "category": "Repost", "title": "Why is nuclear war generally considered to be the end of the world, when hundreds of nuclear tests have been performed around the world for decades and we're all still here and doing fine?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhf2scg", "dhf2s5k", "dhf3948", "dhf36ej", "dhf40jb"], "text": ["Hundreds of people fire guns in shooting ranges and no one is injured, this must no one will get injured in a gun fight.", "Hundreds of tests in isolated areas across decades is very different than a thousand or more in one day in places like cities and military bases which will in turn burn for a long time.", "The human impact is much worse than nuclear tests in unpopulated areas (obviously). It might not kill every human but would be tragic. Also, the world is a very interconnected place and if a nuke went off in New York for example, financial exchanges, corporate offices, and a wide variety of internet services would stop working. Not to mention electrical power, etc, though that would be somewhat more localized, while somebody in China would immediately notice those other services stopping. It might not end the physical planet, but it would alter or destroy the structure of civilization as we know it.", "It isn't the first launch that is as worrying as the second through the hundred and twentieth, leaving very little to no land that isn't irradiated and unsuitable for living.", "\"Nuclear War\" implies that 2 or more sides of a conflict are armed with and have used nuclear weapons. Nuclear tests are conducted in isolated areas, with no inhabitable human population on one's own soil. Nuclear war would mean dropping a nuclear bomb over a (probably) densely populated area on someone else's soil. That country would then in turn drop a nuclear bomb over one of your densely populated cities. As retribution you would then drop a different nuclear bomb on a different densely populated city in their country. Eventually other countries become involved and come to the defense of each of the original 2 countries at which time nuclear bombs are dropped on THEIR densely populated cities...... So along with mass extinction of the human race among the warring countries, there is also the economic impact and uninhabitable land, nuclear fallout, irradiated soils, poisoned food and water supplies..... War is much different than tests."], "text_urls": [[], [], [], [], []], "score": [10, 9, 4, 3, 3]}}, {"q_id": "6ak32i", "category": "Repost", "title": "How do car horns lower in pitch as the car honking gets closer then farther away?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhf3sk3"], "text": ["This is due to something called the Doppler Effect. The pitch of a sound is determined by its frequency - how close together the waves are. If you imagine a speaker pumping out a solid tone, the waves are coming out at nice even intervals and the tone sounds the same. Now imagine that speaker is rushing towards you - the interval gets shorter and shorter as the speaker moves closer to the last wave it sent out, so the sound is higher frequency and thus higher pitched. As the speaker moves past and away from you the opposite happens - the waves get farther from each other each time, and so the sound lowers. This happens with all waves, including electromagnetic waves like light. We can tell that galaxies are rushing away or towards us because their light is shifted towards the red, lower frequency, end of the spectrum as they rush away - hence the term redshift."], "text_urls": [[]], "score": [4]}}, {"q_id": "6amhqe", "category": "Repost", "title": "Memory Leaking", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhfohrv"], "text": ["\"Leaking\" is a metaphor. It actually refers to a situation where a program tells the computer \"I need to use some memory\" and then forgets to say \"I'm done using that memory.\" Over time, the computer allocates more and more of its memory to this program, making it hard for other programs to run."], "text_urls": [[]], "score": [8]}}, {"q_id": "6anoht", "category": "Repost", "title": "If cancer is an uncontrollable division of cells in the body, how does this cause harm to the body? Why is it such a bad thing that cells divide uncontrollably?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhfysu6", "dhfyrsf"], "text": ["Masses of these uncontrolled cells grow and grow. They grow into large clumps which are called tumors. These tumors can push against vital organs or against your skin, creating blockage and ripping tissues. The worst thing that can happen is that it gets in your blood, meaning these tumors can start growing all over your body, including your brain. Its like masses of cars started crowding in the street. If there were enough, they would crash into buildings and block the roads. Also, most cancer cells don't function like regular cells, making them, to you, essentially a dead-alive mass. Zombie clumps growing in you.", "Because those cells can't die by natural ways. They keep dividing without any control and expanding it's size, pushing the organs and muscles (tumor). Also, when a organ is affected by a cancer, it's function is compromised, causing N complications to the organism."], "text_urls": [[], []], "score": [5, 3]}}, {"q_id": "6aorma", "category": "Repost", "title": "how are hummingbirds able to hover and fly in any direction? To clarify, what is going on aerodynamically that allows this to happen?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhglah3"], "text": ["Pretty much in the same way as a helicopter, except the wings don't go all the way around, but move back and forth instead. While flapping they generate lift/thrust, which supports the bird in the air. There is a lot of aerodynamically interesting stuff going on around the wings, and the birds make small adjustments to the wing angles to control themselves, but that is rather beyond eli5. Just ask if you want more details."], "text_urls": [[]], "score": [5]}}, {"q_id": "6ap7tv", "category": "Repost", "title": "Why does unplugging and plugging back in a device work so well with troubleshooting?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhgf0kh", "dhgdpzk", "dhge7hf", "dhgeisy", "dhge69j", "dhghxjb", "dhgea2n", "dhgdtjp", "dhgdr7j", "dhgjyjd", "dhgh9k5", "dhghibj", "dhgik64", "dhgfc30", "dhgjqoq"], "text": ["Unplugging a device is like flushing a toilet instead of trying to scoop the shit out by hand. If you don't hold the handle long enough the shit doesn't get completely flushed down, but once everything is flushed out you got nice clean memory to shit in again.", "With many devices that have a computer chip inside, unplugging them clears out the memory cache, which is often clogged up with some error. So when you plug it back in, the memory cache is free to operate as normal again. With laptops and smart phones, it's often some poorly coded program or website that's eating up a ton of resources and running in the background. When you reset your computer or smartphone, those background apps usually don't start again until you tell them to. Pro-tip: with your laptop go into settings and deselect half the programs that automatically start up when the computer is turned on. It will load way faster and your system won't be as clunky. Edit: Clarifying, I meant that half the programs that are set up to open automatically when you start up your computer are probably bloatware or unnecessary, so you can set it up so that they do not start up when the device is powered on.", "Imagine you're playing a game of chess and in the middle of the game you realize both bishops are on the same color. You don't remember which piece was which, and you don't know how many moves to go back to fix the problem, so the only solution is to return all the pieces to their starting positions and start again.", "For computers, RAM is probably a term you hear tossed around a lot. It differs from, say, a hard drive in some pretty major ways. You can think of RAM as the work bench where a computer places files it's using immediately, while the hard drive is storage space. (Trust me this all comes back around to the plug eventually.) So, when a computer is running, it generally loads a file from the hard drive into RAM, then performs its operations on the RAM copy. There's a bunch more technical stuff to explain, but to answer your question that's pretty much the big thing to know going forward. So, sometimes when something is going wrong with an electronic whatever, there are messed up programs or files being run out of RAM. And this is where the most important part of this explanation comes in- unlike a hard drive, RAM is impermanent. It relies on a constant supply of electricity to operate, and does not retain its data when its shut down. So, much like how you can lose a big document you haven't saved in a while when your toe hits the power strip, when you unplug a device, it loses the supply of power to its internal memory. At this point, any data loaded into RAM vanishes once it's discharged, which happens pretty quickly. When you plug it back in you're essentially forcing the device to reload its files back into RAM, which generally fixes the problem unless you've royally mucked up the files on the device's permanent storage.", "Did you ever think, \"maybe it would be easier to just move house rather than maintain the one I have\"? That's basically what happens. Computer software has a lot of things to keep track of. It does a bad job of this, because the guy who wrote it assumed everything would always work and no errors would ever occur, and therefore any error that in fact does happen causes the whole system to get placed into an unstable state. So if you reboot the thing, it's like moving into a nice new clean house, ready for you to fuck up all over again over the next few years.", "There are several reasons why unplugging and plugging it back works so well, as it addresses several modes of failure in hardware at the same time: * The original connection may be loose. The unplugging and plugging back procedure reseats the connector to a reliable, tightly coupled state. * The connector may suffer from contact corrosion. The unplugging and plugging back procedure scrapes some corroded material, which is often an insulator, off the contact. * Dust may have accumulated in the connector over time and partially shorted out the wires. The unplugging and plugging back procedure shook or blew the dust off the connector and restored the insulation between signals. * The attached hardware may have locked itself in an undefined state. The unplugging and plugging back procedure [removes and reapplies the power to the device]( URL_0 ), forcing it to a known, reset state. * For computer peripherals, the driver on the host computer may also suffer from a state lockup. The unplugging and plugging back procedure forces the driver to unload and reload its state, restoring its functionality. This is akin to force exiting a locked up application and restarting.", "In addition to some of the other good answers regarding memory and such, electrical contacts in switches (i.e. relays) can stick together once they have electricity flowing through them. So, even if you try to put the switch in off, it stays on. By killing power, you stop the electrical flow which is keeping the switch from turning off. Before computers, electronics were mostly a bunch of switches.", "It either powers down the device, releasing it from the state it was stuck in, or plugging it back in retriggers the initialization logic, which resets the device.", "Lets say you are playing a video game. You are on your adventure in game, but have not hit a save point yet. This means that your data is not stored. But your data is temporarily held in something called RAM. (Random Access Memory.). If you cut your game off, you will lose your progress. This is because the save points take your data and copies them to your Hard Drive. Your game pulls from your hard drive for an initial start up. and if your progress wasn't written, the when you cut it off, your RAM loses everything. There is way more to it involving caches and getting down to the electrical side on transistors, but that's the most ELI5 that I could think of.", "Imagine being tired at the end of the day. Your head is filled with stuff you did during the day. You go to sleep and in the morning your head is clear again and you're ready for a new day. When a computer or device is having issues it often is just very busy doing stuff. When you reboot it you clear out the memory and you stop all running processes. When the device restarts it's fresh and clean and ready for operation, unless there is a bigger issue going on of course.", "Imagine that you are writing on a piece of paper. When you get to the end, you go back and erase everything, and start writing again. After a while, the paper might get all smudgy with stuff that the eraser couldn't get. Or, maybe your mind wanders, and you start doodling all over the page, filling it up. Now it's just too much to erase. The best option at that point is to start over with a fresh, clean sheet of paper.", "There are many good answers here that talk about clearing memory and starting over. There's another piece, temperature. Many devices like routers and modems overheat as a result of their position. When a CPU overheats, it often performs the wrong operation which crashes everything. Resetting the computer not only recovers from the crash, but gives the device time to cool off. You're also likely to change the device position or remove dust in the process. This helps prevent future crashes. LPT, if you find that you are constantly having to reset your modem or router, try changing where you keep it and/or blowing compressed air into it to clear the dust.", "ELI5: Computers remember things. Sometimes the things they remember is confusing to them -- maybe so confusing they get stuck. If they could forget everything, they wouldn't be confused anymore, and they wouldn't be stuck. The best way for them to forget everything is to have them start over from the beginning. That's what the unplugging does. \"When in doubt: reboot.\"", "Imagine you have a sink. The plumber didn't install it perfectly and it leaks ever so slightly. In the beginning, it's nothing. A couple drops in your sink doesn't affect much. But over time it adds up. Soon enough, you have a sink full of water. It makes it hard for you to wash your hands or do your dishes. What do you do? Unplug the drain and let all the water drain away. We call these memory leaks in computers. Software isn't perfect. Occasionally, you get programs that declare objects and forget to free up memory when it's done with the objects. The computer doesn't know that the program is done, so it keeps that space reserved. Over time it adds up and becomes a problem. The solutions are to stop the program so all the space it took up is freed, or restart ether computer and everything starts clean.", "Most of these explanations are terrible. It's not helpful to explain things in terms of RAM, hard-drives, and CPUs. That's all detail. What's really important is that modern electronic systems are incredibly complex and imperfect state machines. My attempt at an answer: Electronic systems are incredibly complex, and generally imperfect. It can get itself into a bad state, especially if given lots of time. It's far easier to develop a system that starts up correctly, that to develop a system that never goes wrong even if it runs for hours. This is why turning a computer off and on again tends to fix things. It also works in miniature when you reload a particular program without rebooting the whole system. Analogy: the longer you go walking in the forest, the more likely you are to eventually take a wrong turn and wish you could start over from the beginning. Imperfect systems eventually take a wrong turn. Fortunately, consumer electronics tend to be quite simple to reset back to their 'starting point'. (If it's something like an air traffic control system then of course you don't get to reboot it at will, but that's part of why critical-systems development is rather hard.) *Edit: Others are right to point out that sometimes the physical act of plugging something in might be what's important, such as in the case of a bad electrical contact.*"], "text_urls": [[], [], [], [], [], ["https://en.wikipedia.org/wiki/Power_cycling"], [], [], [], [], [], [], [], [], []], "score": [3446, 2004, 394, 91, 89, 25, 15, 11, 8, 5, 4, 4, 3, 3, 3]}}, {"q_id": "6awb3b", "category": "Repost", "title": "How do Macy's and other dept stores come up with their continual, seemingly random sales?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhhxzsc"], "text": ["Math, markups, and customer data. They have numbers to predict spending habits based on seasons and they know that people tend to spend and buy more when they are getting discounts on items. Sometimes the discounted ticket prices are based on an inflated MSRP that no one will ever pay full price for anyway, so the \"sale\" is essentially bringing the price down to a normal sales price (this is done with virtually all home furniture). Additionally, interest on store credit cards can wipe out any savings after a month of carrying a balance. Rest assured, those stores are selling at a net profit"], "text_urls": [[]], "score": [3]}}, {"q_id": "6axoqs", "category": "Repost", "title": "In this day and age, why do we still need two seperate machines for washing and drying instead of having some sort of 2-in-1?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhi733u", "dhi732q"], "text": ["We don't - combined washer-dryers are a thing. However, they often have lower capacity than a separate dryer, and if you've got multiple loads to do then separate machines let you wash a second load while the first is drying.", "There are many combined washer dryers on the market, however combining the two in the one machine does increase costs and complexity and you can only do on thing at a time."], "text_urls": [[], []], "score": [11, 5]}}, {"q_id": "6ay8u0", "category": "Repost", "title": "Why do animals love to be pet/rubbed/scratched?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhickcz", "dhid76n"], "text": ["What do you not like being petted and scratched? Seriously feels amazing. They also can't really scratch themselves well so that's another reason.", "Some animals have a specific sensory nerve endings on their skin and hair follicles that activate with deep pressure and petting. Activation of these receptors (called MRGPRB4+ neurons) increases the release of endorphins and oxytocin (pain relief, relaxation, and bonding chemicals). This leads to decreased heart-rate and aggression and puts the one being petted in a state of \"pleasure\". One suggestion of why mammals evolved to enjoy caressing suggests that stroking hair encouraged good hygiene through social grooming. It may also explain why certain hair-covered areas of the human body are more sensitive to touch or associated with pleasure. URL_0"], "text_urls": [[], ["http://www.nature.com/neuro/journal/v10/n8/abs/nn1937.html"]], "score": [4, 4]}}, {"q_id": "6aytt5", "category": "Repost", "title": "Why does black absorb sun rays so much?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhig2pz"], "text": ["Colors we see are perceived by light rays (certain wavelengths) that are reflected. Meaning the object doesnt absorb that color. For example, apples reflect the color red. White reflecting all colors essentially and black reflecting no colors. Since black is absorbing these colors and light rays contain energy it heats up faster. Hope that helps. I may be a bit off on the details but the gist is correct."], "text_urls": [[]], "score": [5]}}, {"q_id": "6b0ox7", "category": "Repost", "title": "Why do sharp things cut?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhiuo8f"], "text": ["Pressure is force divided by area. The sharp edge of a sharp item has a tiny surface area, thus a force being applied across the area will result in a very large pressure. Lots of items have a pressure threshold that, if exceeded, results in the surface being broken. Sharp things can break that threshold more easily than other items because it takes less force to get that pressure."], "text_urls": [[]], "score": [8]}}, {"q_id": "6b1tco", "category": "Repost", "title": "that if global warming is a hoax like some people suggest, then what is the motive behind propagating such a lie?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhj41zq", "dhj49e1"], "text": ["The main argument is money. Some people are under the odd impression that scientists profit handsomely from their research. Others claim there are individuals and businesses who will take advantages of policy shifts for profit (somehow). There isn't really a creditable argument for who benefits from it being a hoax (which it isn't).", "Population management and tax revenue. Climate change is real. Has been for eons. The only thing in question is the impact of civilization on climate change. If humans are not the root cause then TPTB can't demand change and generate revenue. This comment will self destruct in 10 down votes."], "text_urls": [[], []], "score": [8, 5]}}, {"q_id": "6b1wck", "category": "Repost", "title": "How do TV channels know how many people watch TV shows?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhj4t4v"], "text": ["Certain households have a box that tracks what and when they watch, and the results are extrapolated give a hypothetical number of viewers. The exact figures would require everyone to have a box."], "text_urls": [[]], "score": [3]}}, {"q_id": "6b3r4a", "category": "Repost", "title": "why do minor chords give us that sad feeling?", "title_urls": {"url": []}, "selftext": "Is it a genetical thing or is it something we get used to associate while growing up?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhjkby9"], "text": ["The major triad has a consonant or pleasing sound because the frequencies all blend -- they are in the proportion 4:5:6. The minor triad frequencies have the proportion 10:12:15. So for the 3 notes of a minor chord, the bottom note vibrates 10 times for every 12 vibrations of the second note and 15 vibrations of the third note. But why the multiple proportion 4:5:6 would be heard almost universally as bright and happy, and the minor triad as more sombre and serious or sad is still unknown. It stands out though, that the major triad is a much *simpler* ratio than the minor. Possibly it has something to do with the ease of difficulty in which our brain/mind can resolve these vibration ratios and find patterns of harmony and order within them. (Or perhaps feelings/emotions themselves have frequencies/waveforms that share a commonality of shape with the wave patterns in sound, and our brain triggers a match which ignites the emotional sensation!) But surely it must have something to do with these ratios, and the brain as a pattern-identifying machine, and as emotions themselves as somehow linked to these basic patterns, whether genetically or through cultural associations."], "text_urls": [[]], "score": [6]}}, {"q_id": "6b3yf9", "category": "Repost", "title": "Why do pigeons bob their head back and forward when they walk?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhjlkmc"], "text": ["Pigeon's eyes are positioned more on the sides of their cute heads rather than in front like big human. This causes pigeons to be unable to see as clearly as humans do. When pigeons run, their heads will actually push forward as far as they can, stop at that spot while their bodies run past the head till the head is as far back as it can stretch, and then push forward again to repeat the steps. This makes it look like the pigeons are bobbing their heads, and produces a frame by frame motion picture that will allow them to see better. It is like comparing two almost identical photos and looking for differences between them. In this way, they can spot predators, which are usually fast moving or stalking them. Next time you start chasing a pigeon, they will run away sideways from you with one eye looking back at you."], "text_urls": [[]], "score": [4]}}, {"q_id": "6b5392", "category": "Repost", "title": "How/why does a limb \"fall asleep\"?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhjtj03"], "text": ["Your limbs receive blood, oxygen and nutrients via blood vessels. They also communicate to your brain via nerves. Think of the blood vessels and nerves as roads. Sitting in weird ways puts pressure on these blood vessels and roads, resulting in a traffic jam on the roads. The blood vessels cannot bring things to the limbs, and the limbs cannot transmit signals to the brain. The traffic flow doesn't always stop 100% but stops moving smoothly. When your brain realizes that it's not receiving proper signals, it prompts you to change your position and relax your limbs so that the impending nerve damage can be stopped. When you do that, the traffic starts moving smoothly again and things go back to normal."], "text_urls": [[]], "score": [6]}}, {"q_id": "6b606a", "category": "Repost", "title": "why is it important to finish a full course of antibiotics, even when you're feeling better?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhk0zcl", "dhk16d5"], "text": ["TL;DR: antibiotic resistance We take antibiotics for wiping out bacteria, whether it is a bacteriostatic agent (slows the growth of bacteria so that our body's immune system can take care of the bacteria naturally) or a bacteriocidal agent (the antibiotic directly kills the bacteria). Bacteria, however, can develop a resistance to these antibiotics. Let's say you have a 5-day course of antibiotics. You have 100 bacteria causing the problem. After 3 days, you wipe out ~90% and feel better! So you stop taking the antibiotics. Those 10 bacteria might have had a gene that made a protein that provided some resistance against the antibiotic. This genetic information is usually in the bacteria's special circular DNA, called the plasmid (as opposed to its linear DNA). Plasmids have this antibiotic resistance information that can be passed from bacteria to bacteria (via bacterial conjugation), and sometimes across different strains. Eventually, they will thrive again and you might become symptomatic for that infection you thought you got rid of. And then you'll pass that antibiotic-resistant bacteria to someone else, and the antibiotics you took for that will not work as well for the second infected person. They'll take stronger antibiotics or antibiotics with a different mechanism of action. However, if they don't finish their dosage, the story repeats. Until we get something like MRSA. So finish your antibiotics!", "It's actually extremely important to finish taking the whole course. The bacteria causing you to feel sick starts to die off from the antibiotics, but not all at once. Just like people, bacteria comes in varying degrees of strength and endurance. The weaker bacteria die first leaving the stronger bacteria alive. So even if 80 or 90 percent of the bacteria that was making you sick are gone, what's left are more resistant to the antibiotics. These resistant ones will breed even more resistant versions making it harder to kill off later. If this happens enough times in enough people, eventually a strain might develop that isn't effected by the antibiotics at all making them useless."], "text_urls": [[], []], "score": [6, 3]}}, {"q_id": "6b8lgx", "category": "Repost", "title": "Why do fast spinning objects, such as wheels, sometimes create a pattern as if it's slowing down in the direction it is spinning and then speeding up in the opposite direction?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhknye8", "dhknpn3"], "text": ["It is only when you're observing it via something with a refresh rate like a video camera. The most common occurrence is under fluorescent light, which turns off and on really fast (60 cycles per second for the US). Most energy efficient lights have this property these days. There is no eye refresh rate. You won't notice the phenomenon in natural sunlight.", "It have to do with the \"refresh rate\" of your eye. Like a movie, which is a series of images that give you the illusion of continuous movement, you can imagine the wheel like a series of static images of a static wheel in different angles. If the wheel have a particular rotational speed it seems spinning backwards"], "text_urls": [[], []], "score": [4, 3]}}, {"q_id": "6b8vto", "category": "Repost", "title": "How did Einstein become so popular?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhkq459", "dhkq9g3"], "text": ["For one, he really was extraordinary. In his \"miracle year\" he published three articles in widely different areas of physics, all of which were utterly groundbreaking and would be the crown achievement for any physicist. Second, his work on relativity is understandable for the interested layman. It's by no means easy, but if you're willing to read up and study a bit, you can grasp the core of his work without being a physics major. Third, he was still alive and active during a very science-minded time. In the middle of last century, scientists in general and physicists in particular were widely admired and highly respected by the general public.", "Right place right time. He was one of the greatest minds the world had to offer at that time. He is also extremely marketable. The messy hair, easy to relate too, and generally a good person."], "text_urls": [[], []], "score": [17, 4]}}, {"q_id": "6b979k", "category": "Repost", "title": "- why is English the chosen worldwide language?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhkrki8"], "text": ["Essentially, colonialism. The British empire was the largest empire in the world for a very long time, Britain was Europe's superpower, so their culture, and language, spread."], "text_urls": [[]], "score": [9]}}, {"q_id": "6bag6w", "category": "Repost", "title": "why competition like Chess, which does not include physical disadvantages to women still needs to seperate men and women in different competitions?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhl0mvr", "dhkzqqe", "dhl13im", "dhl75il", "dhl9qdz", "dhl3rea", "dhlc3yq", "dhlc8f1"], "text": ["There are not different sections for men and women. There is a Women's sections and an Open, women are free to play in both. The idea is not that male players are somehow superior to women players, but that the women's only section will encourage more women to play through prize pools and titles, as the ratio of men to women is heavily in the men's favour. For example in my country there are only a dozen active women players.", "It doesn't. Women can join any chess competition. In addition, there are also women leagues.", "The all-women tournaments and rankings are meant as marketing. The idea is that there are many fewer women who play chess, and so having women's only tournaments is meant to encourage women to play. Women participate in regular chess tournaments as well. It's hard to find a parallel with men's sports/competition, since there are so few fields that are female dominated in the way that things like chess have traditionally been male dominated, particularly ones that lack a physical component.", "The answer no one wants to accept is iq differences. Men are more towards extremes in the curve. Women are more towards the median. This is why men are statistically overwhelmingly more failures and successes. (IQ based jobs and lack of iq based imprisonment, homelessness, etc) Overall I don't really care, but to deny the stats is kinda silly. *Hey, it's cool to downvote this I expect it and I'm actually feminist! But if you look at the stats across the board it simply just is. Men make more iq based extremes. Deal with it or don't. That's okay!*", "The same thing happens in esports, any female can join any league or tournement, but there are also women only leagues and tournements. Alot of people think just because there are no top tier players, they are being ostrisized, but its just that there arnt as many women playing than men", "As an aside the top ranked female player ever who reached 6th overall refused to compete in woman's competitions for the reason you stated.", "This started out as an interesting question. Policies and incentives like this should be reviewed regularly to ensure that they are still relevant and necessary or else the very thing brought in to help equality can actually create inequality. Many people have very helpfully explained that this is an area where the extra incentives are still very much needed and relevant. You have responded by going to a very negative place that smacks of bigotry. As a result, your very good question now seems totally biased and trolling.", "In case no one has mentioned it, the [bell curve of IQ]( URL_0 ) shows that males have more male geniuses and ignoramuses than females do. Males have a larger pool for potential chess masters than females."], "text_urls": [[], [], [], [], [], [], [], ["https://qph.ec.quoracdn.net/main-qimg-16b03344e557c02d559cc5fac9724be3"]], "score": [802, 90, 67, 42, 10, 9, 8, 6]}}, {"q_id": "6bau5p", "category": "Repost", "title": "why do hairs on your head and some parts of your body continuously grow, but not other hairs, like ones on your arms?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhl6x1e"], "text": ["the hair on your head doesn't continuously grow forever. all your hairs are programmed to grow to a max length, and then they fall out and are replaced by a new hair. if you never cut your hair again, it wouldn't grow to an infinite length."], "text_urls": [[]], "score": [5]}}, {"q_id": "6bcpm4", "category": "Repost", "title": "How come when something really hurts our feelings we can feel it in the pit of our stomach and chest?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhlpw3l", "dhm2zof", "dhlmj8p", "dhm5yqx", "dhm0ej6", "dhlyp73", "dhmaxue", "dhma165", "dhlrs3c", "dhm9w0n", "dhmgmcn", "dhm5wyr", "dhm5trq", "dhm3pjb", "dhm7y4k", "dhm95ps", "dhmdhes", "dhml9gv"], "text": ["Your body and brain and part of the same system. Your emotions impact your body, just like your body impact your emotions. A section of your nervous system lines your digestive tract: the enteric nervous system. It is full of motor neurons that contract and relax muscles all the way from the esophagus to the anus to get your food into your stomach, digested, and eliminated (among other functions). Normally you wouldn't notice it working away, but if things go into overdrive, your stomach can feel weird. [There is quite a bit of overlap between nervous system and the gastrointestinal system. Neurogastroenterology is the focus of a lot of research right now because there is a lot we simply don't know.] Anxiety or stress causes muscle tightness all over the body--it readies the body for fight, flight, or freezing. There are muscles all over your chest, so you feel it as tension or tightness. This response also increases blood pressure, heart rate, breathing, and other functions. The result is that you can feel like your chest is heavy, feel your heart racing, feel your heart pounding, feel shortness of breath, etc.", "There was a study published in 1942, where a man with a fistula (hole in the body) had a clearly observably stomach and colon. The stomach and colon would be white when the man was depressed, and turn red when angry. There are a lot of things going on down there, butterflies, stomach churning. In cases of extreme stress, the body needs to be ready to lighten the load (poop your pants with fear) and divert blood from the tummy to the limbs for running away. the study URL_0", "This happens because our brains and guts are connected through the Enteric Nervous System. This system has over 100 million nerves connecting them, so, when you feel emotional distress it sends signals to your stomach and vice versa. Source - URL_0", "Neurotransmitters in the Brain, like Serotonin (think the chemical that medications like Prozac or Zoloft affect) have receptors all throughout out gut. There is a small medical saying, \"Half your brain is in your gut\". So, when you're excited when that first special someone touches your hand.. you feel you could almost throw-up. And then later that year (or night) when that person dumps you.. you feel like you could throw-up, it's all \"spiked\" and \"depleted\" neurotransmitters affecting not just your brain/emotions, but how your gut physically feels. This is also where tropes like \"nervous people get ulcers\" or \"stressed people poop a lot\" are *sort of* accurate. But not really. Also.. it's why some many people \"eat their emotions\". Eating relieves stress (through a complex mechanism mind-you).. but it's in the same world, stimulation or depletion of these neurotransmitters. P.S.- also, it ties into a lot of what some of the other responses are saying.", "As a follow-up question, I've always wondered if a person who's had a vagotomy no longer gets that \"pit in the stomach\" feeling. Anyone know? (A vagotomy is a procedure to sever the vagus nerve and the parasympathetic fibers it contains to a specific organ or portion of the GI tract. It used to be done as a treatment for intractable stomach ulcers before meds like Zantac and Prilosec came out.)", "Our feelings and our emotions are physical processes in our body and brain. Maybe a more interesting question to ask is how do we get thoughts and feelings from physical processes in our body and brain. There is lot's of interesting science looking into how things like genetics and bacteria in our gut may be correlated with mood and behaviours. Robert Sapolsky is a great place to look into it. URL_0", "When it gets really severe, it's called Somatic System Disorder and your brain's emotions are basically hot wired to your ability to function and if you get too stressed your body starts to shut down. It's finals week for me and the stress has caused me to be nauseous, unable to sleep, unable to eat, and even lightheaded to the point of seeing spots. Practice self care so when you feel those emotions you process them and it doesn't develop into SSD!", "Because evolution takes shortcuts. Emotional feelings are carried on the same network of nerves as physical pain because...well...why develop a second system for emotions when the existing system for pain is usable for both? There is a lot more complexity going on behind it, but this is ELI5. So yes, when you have 'feelings' you are actually 'feeling' them because humans evolved to live in groups and be social. Which kinda sucks sometimes.", "I'm fairly sure it's to do with stress response of the body, and because the receptors that bind cortisol which is your stress hormone, are located in both your brain and gut, that adds to the gut feeling.", "A lot of answers here are close but miss a crucial point. The feeling in your stomach and chest is not a response to the emotion which originates in the brain; it IS the emotion itself in large part. Without the chest/stomach pain, your feelings would not in fact be hurt/there would be no emotion.", "I happened to google something similar a while back, and came across explanations on rejection in particular. I think a lot of hurt feeling-scenarios can be connected to the feeling of rejection - whether it is direct rejection, or by feeling let down/not seen/disappointed on some level. Seems that MRI-studies suggest that rejection/feelings of being hurt piggy-back on physical pain pathways in the brain. One theory is that for survival it has been critical to have good social relations and belong to a group, so it is a real signal of danger when that is threatened/destabilized in some way. Also - it seems that we remember this type of pain more vividly as time goes by: At least I feel that it is harder to conjure up memories about physical pain from a physical injury/illness, than an emotionally painful situation. It is all quite interesting. Also, pain-relief seem to have an effect on this type of pain as well, maybe not surprisingly depending on the way the pain reliever is meant to work. One list of facts (I would check other sources but food for thought) URL_2 Here is a TED-link with a reference or two URL_1 And this article seems to have more references to studies, maybe check this one out: URL_0", "Does anyone else feel this in the hands too?", "Having your feelings hurt causes stress. When stressed, your body releases cortisol. Cortisol is inflammatory and causes a number of bad reactions in the body which can be experienced as you describe.", "I read that your guts have as many neurons as a dogs brain, so a \"gut feeling\" is as much a thought as a physical reaction.", "I see this posted at least once a month but I have never experienced this. I have been super sad before but it all feels mental. Anyone else?", "Also this is just anecdotal from personal experience but i feel like fatty foods like avocados and walnuts decrease anxiety", "It's even possible for your heart to break. Tendons in the heart (heartstrings) can be torn if the heart is drastically overworked like during the panic which can accompany losing a loved one or relationship. 'Died of a broken heart' is a thing", "I feel this all the time from anxiety. It is usually followed by heavy sweats. Worst part is I can never identify why it happens. I'm Disney world right now. Literally the happiest place on earth and it's been coming and going sense we arrived. It's a terrible feeling."], "text_urls": [[], ["https://books.google.com/books?id=JaQauznPoiEC&amp;pg=PA48&amp;lpg=PA48&amp;dq=stomach+changes+color+with+emotions&amp;source=bl&amp;ots=EDEe9z3lEj&amp;sig=_toKsMeFvBf_WvbR4y1daEGdeFg&amp;hl=en&amp;sa=X&amp;ved=0ahUKEwj5k4OFtPPTAhXFy1QKHbkGARgQ6AEIUDAH#v=onepage&amp;q=stomach%20changes%20color%20with%20emotions&amp;f=false"], ["https://goo.gl/dqL0vJ"], [], [], ["https://www.youtube.com/watch?v=NNnIGh9g6fA"], [], [], [], [], ["http://www.huffingtonpost.com/2014/03/13/rejection-coping-methods-research_n_4919538.html", "http://ideas.ted.com/why-rejection-hurts-so-much-and-what-to-do-about-it/", "https://www.psychologytoday.com/blog/the-squeaky-wheel/201307/10-surprising-facts-about-rejection"], [], [], [], [], [], [], []], "score": [4639, 693, 413, 182, 78, 32, 20, 15, 10, 10, 6, 5, 5, 4, 4, 3, 3, 3]}}, {"q_id": "6bda1l", "category": "Repost", "title": "why is it impossible to travel faster than the speed of light?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhlo182"], "text": ["The main issue is that the speed of light is fixed. It's always c, or roughly 300,000,000 m/s. No matter what. That sounds obvious but it really isn't. Speed is almost always relative. If you're sitting in a car going 50 mph and you toss a ball at 1mph from the back seat to the front seat how fast is that ball going? From the perspective of the passengers in the car, that ball went 1mph, but from the perspective of a person outside the car it went 51 mph. From the perspective of another planet, it's going thousands of miles per hour as the earth spins on its axis and orbits the sun. But no matter how fast you're going, if you turn the headlights on that car on, light leaves the bulbs at 300,000,000 m/s. How can that be? what if I was going super duper fast? say 150,000,000 m/s. If I turned on the lights wouldn't the light leave at 150,000,000 m/s relative to me? The answer is no. That light will STILL go 300,000,000 m/s. both to you in the super fast car **and** to a person watching you go past, and an observer on another planet. so if the speed of light isn't changing, what does? Time. Time starts to change for you compared to the other observer. As you go faster and faster, time starts to go slower for you relative to the other person. for 300,000,000 m/s to be constant, when your m changes, the s must also change to keep it steady. As you approach that speed, what happens is your time effectively *stops*. S reaches 0. So the answer is \"You can't because at that point time itself stops for you.\" Now, I'd like to quickly stay that this question gets asked a lot. Without fail someone responds with \"Well, that's not EXACTLY right\" I know it's not exactly right. This is ELI5. I am oversimplifying to get the point across. It's more than right enough for an ELI5 answer."], "text_urls": [[]], "score": [9]}}, {"q_id": "6bdi3j", "category": "Repost", "title": "How do balloons lose air over time even though they are completely sealed?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhlq3l3"], "text": ["There are gaps in the balloon material on a molecular level that are large enough for the molecules of pressurized air inside to slowly leak out."], "text_urls": [[]], "score": [3]}}, {"q_id": "6bemjw", "category": "Repost", "title": "What makes someone allergic to something, and how do those allergies cause reactions?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhlzzi8"], "text": ["Allergies is a response to foreign proteins known as antigens and the body recognizes them and the immune system develops very specific molecules called antibodies to combat the antigens. So if there is not enough antibodies present, it causes the allergic reaction. The reaction is caused by disruption of mast cells which release histamine, which causes the dilation of vessels, resulting in faster and more blood flow in the area (gives the skin red color and increase in temp). Histamine also constricts bronchioles which causes difficulty breathing."], "text_urls": [[]], "score": [3]}}, {"q_id": "6bgtrn", "category": "Repost", "title": "Why does hunger striking actually work?", "title_urls": {"url": []}, "selftext": "If, for example a person hunger strikes as a protest against a government, why not simply ignore hunger strikers and let them starve themselves until they either die or give up?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhmga1q", "dhmlxkn"], "text": ["Because it paints the people letting the starving take place in a bad light. It makes them look callous and unforgiving, and some groups do not want to be viewed like that. Sure, no one would hunger strike if authorities just laughed and goaded you, but you would NOT want to be under an authority like that.", "A, Its generally part of an attention grab, the news will often report on hunger strikes, bringing attention to the issue. Which will have lots of people asking \"What about this issue is so serious that someone is willing to risk his health for it\" B, despite how amoral we like to paint the government, the government is still composed of people, most people aren't fond of being the cause of someone dying, even if they are dying for a weird/stupid/wrong reason."], "text_urls": [[], []], "score": [7, 3]}}, {"q_id": "6bjtxm", "category": "Repost", "title": "Targeted Ads... starting to creep me out", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhn68gf"], "text": ["I know what you mean... They definitely \"listen\" Idk if it works everywhere but here in texas if you leave your phone in a room with a spanish station for a few hours you start getting ads in spanish"], "text_urls": [[]], "score": [3]}}, {"q_id": "6bjxo9", "category": "Repost", "title": "Why does time seem to go slower as a kid and faster as you age?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhn79n4", "dhn7bbl", "dhn7go3", "dhn7gkm"], "text": ["You experience time as a fraction of your overall existence. The more time passes, the smaller each unit of time is in comparison to your overall lifespan and the faster it seems to move. For example: if you are 3 years old, 1 year is 1/3rd of your life. Thats much larger than 1/30th at 30 years old", "Perspective. 1 year when you are 4 is 25% of your life. When you are 30, its 3%. Also, you have fewer new experiences as you grow older with less memorable events / milestones", "Perception and actual time experienced seem to go hand in hand. As a kid, you have not experienced as much time, so there is really no base to go off, as you gain years on your belt, there is a reference point of what 5, 10, 15 years felt like before. It also seems to correlate with amount of free time vs duty time. -Not an Expert, just my perspective on the question", "As each year passes, it represents another fraction of your lifetime. thus seems like its speeding up. 1 year old - 1 year is you whole lifetime. 10 years old - 1 year is a 10th of your life. 40 years old - 1 years is a 40th of you life. And so forth... As you get older a year becomes a smaller fraction in your total lifetime, making each year seem faster than that of when you were younger."], "text_urls": [[], [], [], []], "score": [6, 3, 3, 3]}}, {"q_id": "6bof6f", "category": "Repost", "title": "how come birds don't get electrocuted to Oblivion when they land on a power line?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dho7iw9"], "text": ["Electricity always travels from high voltage to a ground. The ground is always 0 volts. When the bird lands on a line they are not grounded. Additionally the resistance through the birds body from one foot to another is greater than the resistance of the copper wire between the birds feet. The electricity follows the path of least resistance and goes from highest energy to lowest energy at the grounding point, avoiding going through the bird. (Using a water analogy, voltage is electron potential I.e. Potential energy, like water in a dam before it flows through)"], "text_urls": [[]], "score": [8]}}, {"q_id": "6bsdzr", "category": "Repost", "title": "Why do scars and previously broken bones ache when there is a change in weather?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhp6hzd", "dhp6q8n", "dhp6dl2"], "text": ["Orthopaedic surgeon here... The real answer is that we have no idea. Some people will say that it has to do with pressure changes in the atmosphere and how that effects scar tissue or healing fractures. However, this doesn't pan out when you actually try to look at it. Not everyone gets this sort of pain, and even people who do get this pain don't always get it with pressure changes. Such as airplanes, traveling to the mountains, etc. It's completely unpredictable. However, it is totally a thing. It is absolutely a real phenomenon that people experience. We just have absolutely no idea as to exactly why.", "Strip club DJ here.....I think that your body remembers the weather conditions last time you did some stupid shit,and automatically warns you of the danger when weather conditions are recreated.", "I've never really noticed my scars aching with a weather change, but why do scars turn so obviously purple or white in the cold?"], "text_urls": [[], [], []], "score": [424, 25, 9]}}, {"q_id": "6bsrm2", "category": "Repost", "title": "Why do schools in the US invest so much money in sports when education appears to be falling behind?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhp8hsa", "dhp9fa9", "dhp9yud", "dhpa0eh", "dhph4p7"], "text": ["College sports are billion dollar industries because the nation as a whole is invested in alma maters, student athletes, sports in its \"purest form,\" and the idea that \"I followed this player before he made it big.\" That's why people like Coach K have multimillion dollar salaries. It's economics, supply-and-demand.", "There are a few justifications. For starters, *physical education* is still education. Schools should also teach their students about their bodies and the best practices to stay healthy. Like or not, sports are an important part of our culture and schools *should* be teaching them. So even if we don't want schools to be spending [literally tens of millions of dollars]( URL_0 ) on a stadium, we *do* still want schools to spend *some* amount of money on physical education. It also just helps kids stay healthy. Even high school kids are still *kids*, they need time to be active and do something they find *fun*. Sports are a fantastic way to do that, and many will justify the cost of sports activities for school by saying it keeps kids healthy and keeps them out of trouble. If you care about your place on the football team, you'll be too busy practicing to be out doing drugs or drinking. You will probably also avoid a lot of drugs even when you have the time because you know it will hurt your performance. Those are fine arguments for sports, but not really a good argument for spending *millions* of dollars. A side-note: it's important to understand how the education budget works. People can donate money to a school or school system with stipulations on how it can be used. If someone donates $10 million for a stadium, the school can't say, \"Sorry, we decided to use your money for books instead\" no matter how good if an idea it might be. Likewise, if the state legislature approves a budget of such-and-such dollar amount for a stadium, that money has to be spent on the stadium. Why would the legislature approve that budget? Because the voters want it. The point is, often it's outside of the control of educators and even the administration over the educators. Usually at the chagrin of the educators that would very much like that money to be spent elsewhere. The usual justification for spending *millions* on sports is that it will supposedly produce millions in revenue for the school. If you know that 4000 parents want to see a high school football game, and you know they'll pay for tickets, then building a huge stadium that can seat that many people and create a spectacle that will encourage more people to come is actually an *investment*. **Personal opinion time**: This is bullshit. Schools aren't about making money, they're not about profit, and if I actually believed that revenue was being funneled back into giving the students a better education away from the stadium, I might be in favor of it. But it never is, it always gets recycled back into the sports activities to make more money for more sports for more money...etc. But as I said, it's usually not up to the educators (which is one of many reasons I did not finish my teaching Master's degree and go into education). For the voters' part: they get just as caught up in celebrity worship as they do for college or pro level sports. Parents want their kids to succeed at sports, they vote for better sports stuff because they believe it will help their kids get to the pros. Or they just want a bigger stadium so they can watch the game.", "With high schools, we don't necessarily invest a lot into it. To play sports costs money. Football players had to pay $1,000 per season! When I was in high school, the budget was always getting cut, and sports (especially JV) were the first ones to be cut. Many sports had booster clubs to help raise money to hire coaches and pay for equipment.", "Because there's no billion-dollar March Madness for academics. Even if there were, no one would watch it.", "Because sports makes more money and that means fatter paychecks for the top people at universities who don't give one flying fuck about the students or education, they are only there to pad their pockets. Universities are the biggest scam in the world."], "text_urls": [[], ["https://www.nytimes.com/2016/05/12/sports/high-school-football-stadium-texas-63-million.html?_r=0"], [], [], []], "score": [22, 20, 5, 4, 4]}}, {"q_id": "6bvbmd", "category": "Repost", "title": "Why do streaming videos and Youtube take up so much data, but playing online games don't?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhprxoc", "dhprukt"], "text": ["With most games it is your computer that is generating the images you see. It's not just receiving video from a server. The data a multiplayer game needs is small compared to video. It's things like the positions of other players, who's shooting who, positions/velocities of objects and so on. The game uses this information to generate the image you see. Your computer already has the data relating to things like textures, models, sound effects, etc because that's typical in the game data you have installed.", "Game data includes things such as sounds, 3d models and textures. These assets are already available on your hard drive when you install the game. The graphics engine uses the models and textures to create the video on the fly. When you play an online game, the data that gets sent between your computer and the server is only things such as the locations of each player, which models and textures they use (not the complete models and textures, just their identifiers), what actions they do and so on. All of this takes up very little space."], "text_urls": [[], []], "score": [13, 3]}}, {"q_id": "6bwlak", "category": "Repost", "title": "What was the Watergate scandal?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhq1ofi"], "text": ["Nixon ran the White House kind of like a criminal enterprise. In his mind, you could get what you wanted either the clean way or the dirty way, and he had people devoted to both approaches. During his 1972 reelection campaign, a \"dirty work\" team called the Plumbers (because they were created to \"plug the leaks\" that had been happening about the Vietnam War) broke into the Democratic Party HQ in the Watergate hotel complex in Washington DC. They took photos of documents and planted bugs, but a couple of them were caught by security. Over the next couple years the diligent work of investigative journalists at the Washington Post uncovered that this break-in was not a simple burglary or even a political job by some Republican zealots, but instead part of a whole campaign of \"dirty work\" that originated in the White House. As the investigation progressed, Nixon made increasingly desperate attempts to make it go away, but was ultimately impeached and resigned in 1974 before his trial before the Senate, which could have removed him from office. The irony of the whole thing is that the 1972 Democratic presidential campaign was a mess and lost in a huge landslide, so the break-in was completely unnecessary to get Nixon elected. Also, Nixon did not directly order the break-in, one of his subordinates did. So while it would have been a big national scandal regardless, if it weren't for his efforts to cover it up, it likely wouldn't have ended with his personal implication and resignation."], "text_urls": [[]], "score": [9]}}, {"q_id": "6bx014", "category": "Repost", "title": "If I took Advil and had a bad headache, a sore foot, and a sore throat, would it \"prioritize\" those issues?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhq4x0c", "dhq4y5e"], "text": ["No. The drug has to disperse through your entire system. The anti-inflammatory effect acts on your whole body, injured/painful parts and parts that don't need the Advil. Any difference in the time those things you mention respond to Advil is due to how quickly their swelling can go down, and the drug's ability to help them in the first place.", "No, advil doesn't know anything about how you feel. It simply inhibits the ability of your body to utilize enzymes that are involved in inflammation responses."], "text_urls": [[], []], "score": [11, 5]}}, {"q_id": "6bx525", "category": "Repost", "title": "Why are Windows computers more prone to viruses than Macs?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhq5xop"], "text": ["simply because of market share. if there were more macs than windows PCs then it would be the macs getting the most viruses. the people writing the viruses these days are usually out for monetary gain so they write them to target the largest group they can, and thats windows PCs."], "text_urls": [[]], "score": [4]}}, {"q_id": "6bxwxj", "category": "Repost", "title": "Why is there no cost difference between hard media and digital media? (cost of discs and cases etc.)", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhqdas1", "dhqebyb"], "text": ["If you buy a digital game on a console, you only can buy it from the console-maker's digital store. Therefore, the console-makers control the digital prices for their media. They tie the digital prices to physical prices in order to not upset physical retailers (Gamestop, etc.). Physical retailers can choose to boycott a game or even a console if digital prices are set lower than physical prices (they only make money through physical sales). A large portion of console games are still sold physically rather than digitally so console-makers would only lose if they make the physical retailers mad. This is in contrast to the PC market where most games are in digital format and physical media is very hard to find nowadays. Because there is no controlled marketplace for digital media (a developer could just send you the game key through email and you can run it without any issues), digital prices can be set without considering the price of physical media.", "Because, at least for books, the cost of manufacturing goods is pennies. The big publishers own their own equipment, have big distribution networks, and removing physical production from the equation doesn't really do much to the final cost when the majority of the money needed to be recouped comes from \"first-run\" costs like paying an advance, editing, typesetting, marketing, etc. Video games and CDs are likely not that much different in that regard."], "text_urls": [[], []], "score": [5, 3]}}, {"q_id": "6bxxqk", "category": "Repost", "title": "How does a scientist (or nutritionist) look at a piece of food and determine how many calories, or how much protein/fat is in it?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhqdo5j"], "text": ["The easiest way calorie content is determined by burning the food and measuring how much heat it creates. You can also measure the contents of the food and calculate. Protein content is measured by measuring the total amount of nitrogen in the food, and using that to calculate the amount of protein in the food. This is generally accomplished using the \"Kjeldahl Method\" which involves mixing the food with sulfuric acid. The sulfuric acid attacks the protein in the food, creating ammonia (which contains nitrogen). The ammonia can then be captured and measured. A conversion factor is then used to figure out how much protein went into creating the measured amount of ammonia. Fat are probably the easiest thing to measure. Fats are soluable in a number of solvents. So you arrive at total fact content you wash your food in ether, the ether dissolves out the fat. You can then either simply measure how much mass the food lost, or you can perform a more detailed analysis of your fat/ether solution to determine things like saturated vs unsaturated fat content. Sugars (carbohydrates) are measured in a similar way to fats, except instead of using solvents, you use water with a bunch of different 'helpers' added to it that make it easier for the sugars to dissolve. There is also sometimes a \"well, it isn't anything else, it must be carbs\" approach that gets used. Measure everything else in the food (fats, proteins, ash, etc.) and what's left is carbs."], "text_urls": [[]], "score": [3]}}, {"q_id": "6bylzt", "category": "Repost", "title": "Why is it that when you're woken up from a few hour nap, you feel very groggy and still considerably tired, almost more tired than you were before the nap?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhqj7la", "dhqiw9l"], "text": ["My knowledge of this is actually from the area of researching decision making, because this is something done to manipulate the quality of decisions. Right after you wake up, you're experiencing sleep inertia. Even though you're conscious, your body is actually still waking up as part of it is still shaking off sleep. Your brain isn't fully going yet, so your cognition is slowed, as are some of your sensory perceptions. For some people this lasts a few minutes, for others it can drag on for a few hours. There is some evidence that indicates that where you are in your sleep cycle will influence how long it takes. When you're in your deep sleep cycles, it will be a little harder; when you're in REM or other shorter sleep cycles, you can wake up faster. Also, you might feel more sleep inertia if you're already sleep deprived, because that alters your sleep cycle as well. It was suggested to me that if you're going to power nap, do it around your sleep cycles to avoid sleep inertia as much as you can. For me, that means I don't exceed 20 minute naps, or I set aside enough time to make sure I get through an entire sleep cycle. One of the best hacks I know is to drink a cup of coffee, then nap for 20 minutes. It takes about that long for caffeine to kick in, so you wake up with a little extra oomph and avoid the sleep inertia. Edit: Clarification - I research decision making, so my primary knowledge is in what happens during sleep inertia, and how to improve/avoid it.", "They call it sleep inertia. Basically if you take a nap much longer than 20-30 minutes or so, your body gears down for deep sleep cycles. A few hours into a normal night of sleep, you're in some of the deepest cycles, and the feeling you describe is the feeling of being woken from that suddenly. During a short nap you don't get into this state quick enough, and after a full night's sleep your body has time to naturally complete the cycle and wake."], "text_urls": [[], []], "score": [4, 3]}}, {"q_id": "6bytuo", "category": "Repost", "title": "How does a computer work", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhqmqkr"], "text": ["When you build a PC, here are the main parts you need: * A case. This is optional if you want to be artistic, the case is just a good place to keep your parts and it has places to put your cooling system. [Here's an example of someone who didn't use a case.]( URL_0 ), but it has a cooling system attached. * Motherboard - This is the main circuitboard that holds several components like the CPU, memory, and the cables that go to your drives. You usually attach this to your case. * CPU - aka Central Processing Unit. This is the brain of your computer. Usually people use the analogy of a person working at a desk to describe a computer. In that analogy, the CPU would be the person (I'll continue the analogy below). * Memory - called RAM (Random Access Memory). In the analogy, RAM is your desk. This is where everything runs while you're using the computer. The more RAM you have, the more things you can run at a time. So more RAM means a larger desk, so you can have more work out on the table to work on. RAM is only active when the computer is powered up. * Hard Drive or Storage - These were called hard drives back in the day to differentiate them from floppy drives, but now Hard Drive refers to a specific kind of storage device (more people are now using Solid State drives for their speed). It holds all of the permanent data for your computer. In the analogy, this is your filing cabinet. It can hold your data when the computer is off. It is also used to help out your RAM if you need more of it. * GPU/Graphics Card/Video Card - GPU is the more preferred term these days to equate it to CPU, but specifically for graphics. This is the piece that your monitor attaches to. If you play games that are very graphics-heavy, you need a separate GPU, otherwise your CPU cannot keep up. In the analogy, this would be your assistant for specific graphics-related projects, because she's a great artist, but you (the CPU) still run the show. * Power Supply - This is a bit self-explanatory. It powers your computer. In the analogy, it would be your lights (in a world where you cannot work at all without light). That is what a computer needs. If you'll go back to the image I linked for the Case... On the top-left is the Power supply. Moving to the right is the motherboard. Those 3 rows of red things on the motherboard are the RAM. To the left of the RAM (the thing with those 2 thick red tubes running to it) is the CPU. The barber poles to the right of the motherboard is the cooling system (this is using liquid cooling as opposed to fans). To the right of the cooling system is the storage. The big rectangles on the top are Hard Disk Drives (HDD). The 4 orange rectangles below them are Solid State Drives. Storage is kind of like real estate. The Hard Disk Drives on top are slower, but can hold more data for less cost (and in fact, the 2 with black labels are faster than the 2 with green labels. The green label drives are more energy efficient), so there are 3 tiers of storage. Stuff like photos doesn't need to be on the fastest drives. Stuff like games probably need to be on the fastest drives. On the bottom-left is the sound card. I didn't mention it above because most people use the sound hardware that is built into their motherboard. But if you are using a system that is built for impressive media, a sound card is the audio equivalent of the GPU/Video card. It's just taking strain off the CPU, and doing a better job. Also, I'm kind of guessing it's a sound card based on those green/orange cables coming out of the left side. Those are fairly standard colors for Sound Out and Sound In ports. To the right of the sound card is the GPU. The GPU produces a lot of heat, so you'll notice the cooling system has tubes that sit on top of it to dissipate heat. The thingies on the bottom right I don't know what they are, but they're probably temperature gauges (?)"], "text_urls": [["http://i.imgur.com/5F5uUYA.jpg"]], "score": [3]}}, {"q_id": "6c0cro", "category": "Repost", "title": "How do boomerangs work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhqyrgg"], "text": ["A boomerang is essentially a spinning wing. Because it's spinning , one half of the wing is moving through the air faster than the other half. Think of how the part of a bike tire touching the ground is momentarily stationary, while the part furthest from the ground is technically moving twice as fast forward as the rest of the bicycle. Because one half has more lift and because it is spinning, it cannot travel in a straight line. The thrower has to predict the curve if they want it to return. Helicopters would have this same inability to fly straight if it wasn't for the fact that they can change the pitch of their blades, compensating for the difference in lift on each side of the spinning wing."], "text_urls": [[]], "score": [6]}}, {"q_id": "6c2s2e", "category": "Repost", "title": "How does Facebook know what I've Googled?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhrgk2e"], "text": ["Facebook also allows advertisers to place a \"pixel\" on their website to track you and retarget you with ads. So, if you went to the airbnb website, you got retargeted by a pixel."], "text_urls": [[]], "score": [4]}}, {"q_id": "6c4qgj", "category": "Repost", "title": "Why are rhymes so satisfying to hear in things like songs and poems?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhruwho"], "text": ["Humans have a very strong ability to recognize patterns (due to our large brain compared to body size). It is what made our species so successful as humans can build upon the patterns of our predecessors in science and the arts. That is why most of the posts on /r/oddlysatisfying can be distilled into patterns (things fitting the way they should, objects moving in very patterned motions, etc.). Rhymes themselves are a pattern of word and sound and it satisfies us when they are properly used in songs and poems. Puns are satisfying in a similar way."], "text_urls": [[]], "score": [3]}}, {"q_id": "6c4si2", "category": "Repost", "title": "Why is \"XXX\" associated with sex, nudity, and porn?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhrv8li", "dhs93ce", "dhsjm96", "dhsidd9", "dht0fet"], "text": ["The movie ratings organizations used to have an \"X\" rating for movies that were above and beyond \"R\" rated. IIRC, this has since been changed to NC17. Because X rated was associated with explicit scenes (though this included violence, not just nudity), it became a positive marketing point for pornografic films, who were specifically targetting an audience *seeking* explicit content. XXX was to denote even more explicit content than just \"X\". URL_0", "The way I heard it explained once was that: X meant melons and buns, XX meant hotdogs and clams XXX meant lemonade and brownies", "Wait... Then why is it that in those older bugs bunny-esk cartoons, moonshine/liquor was labeled with XXX?", "I read that they used to censor covers of porn mags with X over the nipples, butts, vaginas... So, boob only cover would have XX on the nipples, while full frontal nudity provides XXX censorship. Surely, pictures with full nudity are more desirable, so the XXX mark cought on.", "I have always had the suspicsion that the city of Amsterdams crest had something to do with it. EDIT- sorry i should have elaborated a bit. The crest dates back a long a time and Amsterdams sex, drug and drink industry goes just as far. This explains the old bottles with it on and why its almost always been associated with forms of tabboo"], "text_urls": [["https://en.wikipedia.org/wiki/X_rating"], [], [], [], []], "score": [202, 35, 30, 14, 5]}}, {"q_id": "6c5rra", "category": "Repost", "title": "Why is the human population almost 50/50 male/female?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhs5cqn", "dhs3mbe"], "text": ["/u/Teekno has given an accurate description of how the mechanics work. However, that doesn't explain why the mechanics are the way they are. Theoretically, it's better to have 5 or 6 females for every male in an evolutionary sense because one male can impregnate several females, genetically satisfying both sex's need for procreation. So why then do most species tend towards 50/50 splits? Genetic competition. If we envisage our world with six women to every man, male children would be massively advantageous. One male child would guarantee you many more grandchildren than one female child. Thus, it's advantageous to have sons. Those that randomly do produce more sons due to an inheritable trait have many more children and outcompete potential genetic rivals. Because the strategy is so successful the \"male favoring\" gene spreads throughout the population, skewing the ratio towards men. Theoretically the same thing would happen in reverse with too many males. Daughters would become favorable because they'd guarantee grandchildren, so female producing genes would become favorable. Because of this competition, most species settle on 50/50 splits. How do we know this is true? By looking at the exception to the rule. There are species that do produce many more females than males. What do they have in common? They're incestuous. If you aren't competing with other families, genetic competition doesn't matter as much anymore because you all share similar genes. So it becomes more logical to maximize the number of females to increase the number of descendants, thus favoring the incestuous family.", "So, you probably know that males have an XY chromosome pair and women have an XX pair. In the man's sperm factory, the DNA is split down the middle. Each half goes into its own sperm. One half has the X chromosome, and the other half has the Y. So, half of all the sperm carry X, and half carry Y. Of the millions of sperm, if one makes it to the egg, it matches up with the X chromosome all eggs have."], "text_urls": [[], []], "score": [11, 6]}}, {"q_id": "6c7xqh", "category": "Repost", "title": "Why has technology progressed so much faster in the past few years?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhsn19i", "dhsn7d1"], "text": ["The advancement of society has always been limited by the ability for people to communicate and collaborate. The easier and faster people can communicate the more effective collaboration is and therefore the faster we are able to advance. It use to be if two scientists across the ocean each had one of the necessary pieces for eradicating polio, polio would never be conquered. The only likelihood those two scientists would ever even know about eachother is if someone happened to cross both of their paths and relay the information...highly unlikely. With the advent of things like the telegram, transmitting these messages became viable but still a lot of coordination was required on both ends to facilitate the collaboration. With the proliferation of telephones, the communication became even easier and so did collaboration. Now with the internet the communication piece has been completely solved (except for language barriers which continue to be shattered daily) and now we are focusing heavily on how to improve collaboration through the use of repositories (for software dev) file sharing capabilities, video streaming, etc. As we continue to improve these tools, break language barriers, and better organize and centralize information, advancements will continue to accelerate at an exponential rate. We have also evolved to the point where we can have computers work on solving problems with no human interaction; all they need is training sets and computation power.", "This is a common misconception. Today's society considers \"technology\" to be simply electronics and computers. These have advanced quickly in the last few years due to Moore's law and the profitability of computer sales. Lots of research is done in the area by many companies. As for the \"progression of technology,\" we must also consider many other items of human creation. Such as development of building material like concrete or refined metals. The development of transport such as trains/ships, or even the simple tools that humanity created to harvest their fields more efficiently. All these are also technology. Keeping in mind this larger scope of what \"technology\" entails, it's clear to see that at many points in history there were technological explosions that resulted in rapid development. Consider the renaissance or the development of military weapons in the early 1900's, both saw explosive changes in a short period. As for technological and scientific advancement today, it is likely due to a much greater number of educated scientists and intellectuals than existed in the past. built upon millennia of research, progress and technology we are currently undergoing another explosive period of development. But overall it's really not \"so much faster\" than usual."], "text_urls": [[], []], "score": [4, 3]}}, {"q_id": "6c95yd", "category": "Repost", "title": "The Watergate scandal and why it happened", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhsxjp1", "dhsxq5t"], "text": ["*Copypasting from one of my previous comments:* In 1971 (in response to the [Pentagon Papers]( URL_0 ) scandal) a group known as The Plumbers was formed under White House control with the task of performing various illegal activities. For example they burglarized the offices of the psychiatrist of Pentagon Papers leaker Daniel Ellsberg - an act that would later lead to all charges being dropped against Ellsberg. In 1972 the Plumbers were tasked with breaking into the offices of the Democratic National Committee at the Watergate Complex in Washington D.C. and planting wiretapping devices there. They broke in undetected on May 28 but there were problems with the bugs they had planted, so they returned for a second break-in on June 17 to reinstall the bugs. This time a security guard noticed tape over some of the door locks and called the police and the Plumbers were caught red-handed by undercover cops. The White House tried to cover up the whole affair but gradually the facts came out through investigations by the FBI and congress and by a series of journalistic scoops (most famously by Woodward and Bernstein from The Washington Post). Nixon denied any foreknowledge of the break-in and any role in covering it up, but three key events would lead to his downfall: 1\\. One of the Watergate burglars, James McCord, had a crisis of conscience while in prison and revealed everything he knew, 2\\. John Dean, White House counsel, who knew all about the Plumbers and their activities, feared he would become the fall guy for the whole scandal, so he blabbed as well, 3\\. It was revealed that Nixon had a taping system set up in the White House to record most of his conversations. These provided undeniable proof of what Nixon knew and did. In Congress in July 1974 the House Judiciary Committee passed [Three Articles of Impeachment]( URL_1 ) against Nixon. You'll note that the Articles don't accuse Nixon of having foreknowledge of the break-in or of authorizing it. No hard evidence was found or has since been found for that. Nixon was a control freak with a strong attention to detail so many assume he must have known about it - but nothing certain has ever been found to prove that allegation. The Third Article accuses Nixon of ignoring subpeonas from Congress but the other two articles mainly focus on events during the aftermath of the Watergate break-in when Nixon tried to cover up the scandal by paying hush money to the Watergate burglars, trying to derail the FBI investigation through illegal means, lying and withholding evidence, telling witnesses to perjure themselves, and other abuses of power and obstructions of justice. Nixon ended up resigning on August 9, 1974 before the full House could vote on the Articles of Impeachment and before an Impeachment Trial in the Senate could take place. His vice-president Gerald Ford became President. **tl;dr** - a White House unit broke in and wiretapped the Democratic HQ at the Watergate complex.When they were caught Nixon used illegal means to try and cover up the scandal leading to impeachment proceedings against him and then his resignation.", "Explained as quickly as possible, several individuals working on behalf of the Committed to Re-Elect the President (Nixon) broke in to the Democratic Party's headquarters at the Watergate Office Complex. They planted surveillance devices and took pictures of campaign documents. The FBI then turned up links between these individuals and the Administration. Even after the burglars themselves were convicted, several individuals involved admitted to having perjured themselves. These individuals believed that they could prevent Nixon from being impeached by telling the truth. However, this did not end the scandal, a Special prosecutor was appointed and the Senate established a committee to investigate further, and white house staff admitted there was a recording system in the white house. The Special prosecutor issued a subpoena for the tapes. President Nixon refused citing executive privilege and ordered that the prosecutor drop the subpoena, when he refused, he ordered the special prosecutor fired, firing both the Attorney General and the Deputy Attorney General before finally the Solicitor General fired him, this however, only deepened the scandal. The White house did release edited versions of the tapes - notably removing expletives and redacting national security information. This, however, only further served to turn people against him. Eventually, the supreme court voided Nixon's claim of executive privilege and ordered the full, unedited tapes released. After going through the tapes, the investigators found the 'smoking gun' a tape in which Nixon and top aides discussed how to cover up the White House's involvement. With his impeachment by the house and conviction by the Senate certain, Nixon resigned rather than be removed from office."], "text_urls": [["https://en.wikipedia.org/wiki/Pentagon_Papers", "http://watergate.info/impeachment/articles-of-impeachment"], []], "score": [19, 4]}}, {"q_id": "6cabi3", "category": "Repost", "title": "Why didn't the indigenous populations of the Americas spread any disease to the Europeans? Why was the spread of disease so one-sided?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dht4a0e", "dht53gr", "dht56q4", "dht4i6v", "dht49ca", "dht4j2p"], "text": ["The rate of disease and rate of evolution of new diseases are related to the population and population density of a group. The more people there are the more closely they live together, the higher the chances of bacteria or viruses evolving to be harmful to that population. There is also a greater chance that the disease will both spread through the entire population and that some of the population will survive with their own adaptation that helped them survive the disease (immunity). In small disperse populations, diseases are less likely to evolve since there are simply fewer hosts and hence fewer bacteria and viruses to undergo mutation. Native Americans lived in small groups which were generally separate from each other in a large continent. Europeans had large cities of hundreds of thousands of people in high density with poor sanitation and often traded with each other. So it was far more likely that more diseases would evolve in densely populated Europe than in sparsely populated North America.", "They did. Syphilis is a disease spread to Europe from the Americas. There are several factors that contribute to the disease exchange being so one sided. 1) Most deadly diseases that would spread to the Europeans would kill the sailors before they got back to Europe. So they would not carry them back. There were whole colonies lost to mysterious diseases so there is evidence that they did have some transfer to Europeans. 2) Most Native populations did not live in as dense of communities as Europeans did. This means that they spread fewer diseases and would have developed fewer. 3) The Americas did not have as many domesticated animals, which means that they had fewer diseases developed.", "CGP GREY has an [awesome video on the subject]( URL_0 ) with some reference if you want to read more", "Major plagues like Smallpox and Bubonic(Black Death) stem from close contact with domesticated animals like cows, chickens, pigs. These diseases are small time problems for the animals, but if they jumped to humans(it was very uncommon but the size of cities and huge amounts of people living there helped increase the odds ) they could destroy populations(and did so). Major cities like London, where livestock were commonly walked through city streets and remains left on the curb or accidentally tossed in the river meant people were almost always in close contact with animals. The new world had no big cities, no massive population, and no domesticated animals(besides llamas, I think) meaning a plague-like disease had no chance to form. Hope this helps. I'm no expert, a real scientist might better explain it.", "I've heard Europeans had more diseases because they had more domesticated animals. Apparently diseases develop by being passed back and forth between humans and animals.", "We'll probably never know for sure! One major difference is that Europeans were exposed to a much wider variety of livestock animals, over a much longer period of time, than the peoples in North America. Many diseases hop from livestock to humans. There was also a much greater deal of travel, trade, commerce, and warfare all across Europe, Asia, and the Middle East. These two factors combined seems to have led to more germs from a variety of sources in peoples living in Europe compared to people living in the Americas before Europeans arrived. Syphilis may have originated in the Americas but we'll never know for sure."], "text_urls": [[], [], ["https://m.youtube.com/watch?v=JEYh5WACqEk"], [], [], []], "score": [26, 25, 17, 5, 4, 3]}}, {"q_id": "6cbma9", "category": "Repost", "title": "if water is liquid at room temperature, why does it evaporate if left long enough?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhtf2gk"], "text": ["Water is always evaporating and condensing at the same time, at any temperature. If the air around the water puddle is dry enough, the amount of water evaporating is more than the amount of water condensing, which is why puddles slowly evaporate."], "text_urls": [[]], "score": [4]}}, {"q_id": "6cczn7", "category": "Repost", "title": "How do women \"synch\" up during that time", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhtqgvj", "dhtpqtb"], "text": ["It doesn't really happen. People *think* it happens because they'll notice when everyone is in sync. In reality, most women have a cycle that's pretty close, but not exactly, 28 days & runs for a week. This gives a lot of room for overlap. Also, since you've got a bunch of cyclical things with a similar period, eventually they'll line up, like the turn signals on a row of cars at a stop light or [a bunch of pendulums of nearly the same length]( URL_0 ) (seriously, watch this - it pretty much answers your question without any words at all).", "It is really simple: It doesn't happen. There was an old study that claimed it took place which was discredited, but the legend mill never got the message."], "text_urls": [["https://www.youtube.com/watch?v=yVkdfJ9PkRQ"], []], "score": [7, 4]}}, {"q_id": "6cg0z3", "category": "Repost", "title": "Why can we see through glass?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhue04a", "dhuefzd"], "text": ["We can see through glass because the molecular structure of glass is large enough to let the visible wavelengths of light through.", "I'm no expert but... Objects have colour because when the exact correct amount of energy (which comes from light) hits an electron, it is excited into a higher energy state. However, it is unstable in the higher state, and so drops back down to the original state pretty quickly. As it drops it emits some energy as a wave (in the electromagnetic spectrum). So, objects with colour emit in visible light region. For glass and other transparent objects, the amount of energy needed to raise and emit electrons is not quite right, so glass only absorbs UV radiation or something, hence why toucan see through, but not tan through, glass."], "text_urls": [[], []], "score": [8, 4]}}, {"q_id": "6cg5yw", "category": "Repost", "title": "Why does it physically hurt when your heart is broke?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhudnx0"], "text": ["Depression. Depression and anxiety have physical symptoms, some of which are chest pains/tightening in the chest and a lack of appetite. Basically, your body goes a bit haywire in response to the imbalance of hormones in your brain."], "text_urls": [[]], "score": [8]}}, {"q_id": "6chvg2", "category": "Repost", "title": "How do computers keep track of time?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhuqk46", "dhutbyh"], "text": ["> Somehow, it knew the date and exact time without internet access. How is that possible? There is a battery on the motherboard attached to a digital clock, just like in a digital watch. That keeps track of the time even when the computer is not powered.", "Besides the motherboard battery, all modern systems synchronize their time with a time server with a protocol called NTP. There's a list of NTP servers for public use, and some organizations like Microsoft run their own. An NTP server can be a primary source (getting the time from a highly precise source like GPS), or be a secondary that synchronizes with a primary and takes the load off it."], "text_urls": [[], []], "score": [15, 3]}}, {"q_id": "6cjbnr", "category": "Repost", "title": "What is a Raspberry Pi and why is it so good at, whtever it does?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhv28tl", "dhv2bjs", "dhv2ac8", "dhv6x2f"], "text": ["It's a small computer. The latest version has 1GB RAM, wifi, ethernet, sound output, USB ports and HDMI. It's tiny and costs about $40. It's good for whatever purposes benefit from a small, cheap computer. It won't really compete with a desktop or a laptop, but it you want to do something like hanging a screen somewhere for the only purpose of displaying the weather, then it's great at that sort of thing.", "They are basically small, cheap, simplistic, modular computers. They aren't fantastic at doing anything, but if you need to set up a cheap computer network you could set one up for relatively cheap. They are also nice for programming because you can set up cheap testing environment and without worrying about corrupting OS or messing up your actual computer.", "It's a small, cheap programmable computer. Hobbyists like them because they're cheap and simple. There's also a large fan community that publishes plans and designs. URL_0", "I've used several for different things. I use one exclusively for retropi, which is an emulator. It lets me play games from pretty much any console from the original PlayStation and before. NES,SNES, N64, Genesis, PSX, plays Atari and other older consoles too. I've got another one I setup to be a settop box for streaming from my NAS to a tv. I use another one to learn coding. I'll probably use another one to setup a wall display like someone else mentioned. Set it up to scroll news headlines, weather, stock prices, calendar events, etc. they are very useful little computers."], "text_urls": [[], [], ["https://www.raspberrypi.org"], []], "score": [36, 9, 7, 3]}}, {"q_id": "6cjpkz", "category": "Repost", "title": "What does IQ show us?", "title_urls": {"url": []}, "selftext": "There is this famous quote being passed around on Reddit every time IQ gets mentioned. \"The only thing IQ tests measure is how well you perform in IQ tests\". Is this really the case or does IQ really show how likely you are to be successful in the future for example in the academical fields? Does it measure how well you can input information and then put it into use? I've always taught: Average IQ + Motivation > High IQ. But maybe I am wrong.", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhv7ewe"], "text": ["Imagine you're trying to start a fire. Your brain is a match and the outside world is the fuel. An IQ test can determine how good your match is, which is very important on the low end and not so important on the high end. If someone scores very low on an IQ test, it's kind of like they have a wet match. They're never going to be able to get a fire going, and it is in society's best interest to put these people in special education classes. This area is where IQ tests really shine, because low level intelligence is easy to measure. IQ tests are not very useful for determining high-level intelligence. Often times, people that score very high on IQ tests don't manifest more intelligent results. Again, to the match analogy, once the flame is struck it really doesn't make a big difference whether it's the best match in the world or some cheap safety match. The IQ score becomes less important and everything else becomes more important, the higher up the intelligence spectrum you go. All that being said, an IQ score can really show how likely you are to be successful in academic fields, by placebo effect alone. Telling someone they are smart has been measured to have a very powerful effect on their success potential. But even more powerful is telling everyone else that some individual is smart. Even lab rats perform much better on tests compared to other lab rats, if lab technicians are told some randomly selected rats are the smart rats. The lab technicians will subconsciously handle the \"smart\" rat with more care, which lowers its stress, which has a massive impact on test results in rats across the board. All research indicates that the same dynamics also apply in humans."], "text_urls": [[]], "score": [5]}}, {"q_id": "6ck2li", "category": "Repost", "title": "why does water evaporate when its no where near 100\u00b0C?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhv8g5w", "dhv8hef", "dhvabed"], "text": ["Molecules of any substance are bonded by different kind of forces. In ELI5 terms molecules are bonded by holding hands. This bond is weaker in liquids compared to solids. So a water molecule in room temperature only needs a tiny amount of energy to let the hands of his friends go and jump into air. When the temperature increases more and more molecules get kicked into the air.", "Temperature is a measure of the *average* energy of the molecules in the system. Most molecules will be very close to the average, of course, but there will *always* be at least one molecule that is far above the average (and one far below). As the molecules are bouncing around and colliding, they're transferring energy between them, and occasionally several will collide in such a way that one ends up with a lot more. Think about three water molecules all colliding with another one at the same time, all transferring some of their energy into it. That one will gain enough energy to break the weak hydrogen bonds holding it to the rest of the water molecules and keeping it a part of the liquid. Most of the time that happens somewhere under the surface, and that one will smack into another molecules or three and that energy will go right back into the system. However, if that one molecule happens to be at the surface, it will fly off into the air. The warmer the water is, the more likely it is that one molecule will end up with enough energy to fly off. This happens even when the water is frozen - very sporadically, one molecule will jiggle hard enough to fly off the surface of the ice. When there's water in the air (and there pretty much always is) some of those molecules will also collide with the surface of the liquid and get stuck, transferring a little bit of that energy into the system. Eventually, the system will reach *equilibrium* - the rate at which water evaporates off is equal to the rate at which water condenses back into the liquid. Where that equilibrium is depends on the temperature of the water, the temperature of the air, and how much water you have in both. Incidentally, this is how sweat cools you off. When the water evaporates, it takes the energy with it, lowering the average temperature of the water very slightly. This is called *evaporative cooling*.", "Liquid and vapor are in equilibrium at almost any temperature. The amount of vapor that can exist at a certain temperature above a container of liquid is called the [vapor pressure]( URL_0 ). At room temperature, the vapor pressure is only about 3% of the total atmospheric pressure. But whether or not something is close to 3% or close to 0% makes a big different with how humid or how dry the air feels. Anyhow, so what happens if you leave water out is that it will evaporate until the air above it is saturated (~3%) with water vapor. So, it's already humid, this will be slow. If its dry or windy (so that the newly evaporated vapor gets blown away from the liquid) then it will be faster."], "text_urls": [[], [], ["https://en.wikipedia.org/wiki/Vapour_pressure_of_water"]], "score": [16, 13, 3]}}, {"q_id": "6cknst", "category": "Repost", "title": "Why do certain songs bring back so many memories from my past?", "title_urls": {"url": []}, "selftext": "I always end up remembering both things I regret and good memories", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhvet63", "dhvhcke"], "text": ["Think of trying to learn a new language. You're taking in a lot of new information - it's hard to remember it all. You make flash cards for the words you're learning - but it just isn't working. Finally, you draw a picture next to each new word that's going to help you remember - it's a hint for your brain. When you're in class and are tested on your new vocabulary, you are able to remember by connecting the word to a drawing which helps your brain to remember the definition. This \"cue\" triggers your brain to recall a memory - just like music does. That's why elementary aged school children learn \"songs\" to help memorize otherwise difficult things (alphabet, states, etc.). Music triggers such strong and specific memories and emotions because music activates parts of the brain that are responsible for things like creativity and emotions. Music is a sensory experience that provides the brain with a \"hint\" when retrieving a memory. The areas in the brain linked with memory sometimes need cues or alliterations to help retrieve memories - and music is just that, it provides the brain with a rhythmic cue.", "The human brain has a very neat trick up its sleeve called \"associative memory\". When you feel a very powerful emotion (intense joy, pleasure, pain, fear etc), the stimuli you received at that moment will become attached to the specific feeling in your memory. So much that when the stimuli is represented to the brain, you will actually feel the same emotion. Of course there are degrees to this, on one side of the scale are things like PTSD triggers, on the other you have a song reminding you of a particular time in your personal experience. From an evolutionary standpoint it is very useful. Let's say a human stumble on a very rare but dangerous animal, the creature hisses and then attacks. That person would then on associate the sound, smell and other things perceived at that time with the feelings of fear and pain. If and when the human comes upon the same animal again, the brain will very quickly and strongly alert of the danger. Fun fact, this behavior of the brain was known empirically by the Romans. They took advantage of that when conducting business. When two men came upon an important agreement, they would bring a child in, tell him in detail the contents of the contract then proceed to beat the child halfway to death. The trauma induces would make the child remember very clearly what was said for the rest of his life. When grown up, the child could be called as a witness if need be."], "text_urls": [[], []], "score": [4, 3]}}, {"q_id": "6cknzw", "category": "Repost", "title": "When something passes the sound barrier, a sonic boom is created. What would happen if, theoretically, someone broke the light barrier?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhvdv7y", "dhvde7n"], "text": ["While nothing can go faster than the speed of light *in a vacuum* (such a speed doesn't really make sense), something can go faster than the speed of light in other things. Light slows down as it passes through things, which is why refraction works (e.g. for lenses). What you see is a sort of \"light boom\" which can be loosely understood to be like a sonic boom but with light. This is called \"Cherenkov Radiation\" and manifests itself as a bluish glow. It is sometimes seen around nuclear reactors. You can read the Wikipedia article and see pictures of this [here]( URL_0 ).", "Theoretically, you'd feel the result of the action before you saw the action itself. This would pretty much break physics as we know it."], "text_urls": [["https://en.wikipedia.org/wiki/Cherenkov_radiation"], []], "score": [8, 7]}}, {"q_id": "6clsry", "category": "Repost", "title": "Is toothpaste protecting you for the next few hours or is it cleaning up the dirt from the past few hours?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhvm9rx", "dhvus63"], "text": ["Depending on your toothpaste, it does both. The brushing itself - combined with the paste as a sort of \"soap\" - cleans the dirt off and the paste you massage into your teeth build a protecting layer that oughta keep your teeth healthy and keep dirt from sticking to them for some hours. But as I said, depends on the quality of your toothpaste :)", "Both actually. The mechanical action of brushing combined with the toothpaste helps remove bacteria and their biofilms from your teeth. The fluoride found in most toothpastes helps to protect your teeth from future corrosion by oral bacteria."], "text_urls": [[], []], "score": [9, 3]}}, {"q_id": "6cm8wu", "category": "Repost", "title": "How do hairs know when they've grown to a certain length?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhvq202", "dhvpuk9", "dhvpxyb"], "text": ["Hairs don't know. Your hair follicles go through a timed cycle - they grow for a period of time, then they rest, then they shed the old hair and grow a new one. The length of the growth cycle determines the maximum length of the hair.", "When you find out, could you tell my nose hairs?", "Pretty sure the hair on your head doesn't \"know.\" The ends just get progressively more dry and break off."], "text_urls": [[], [], []], "score": [13, 8, 3]}}, {"q_id": "6cp1zq", "category": "Repost", "title": "How come your breath stinks even after only a few hours of sleeping, but can last the majority of the day when you're awake?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhwb686", "dhwb67i"], "text": ["TLDR - bacteria poop A human mouth gets relatively dry when you're sleeping compared to when you're awake. All that saliva in your mouth is good at keeping bacteria from growing in your mouth. But when your saliva production slows down when you sleep, bacteria has a chance to grow and the cause of the bad breath when you awaken is actually all that bacteria and bacteria waste.", "During the night your brain stops or at least largely reduces the amount of saliva secreted. That results in you swallowing less, moving your mouth, tong less, etc. During the day you eat, drink, swallow alot. If i recall correctly, you produce about 2 litters of saliva per day. That's quite a lot to flush the microbes that are still in your mouth. In the end, bad breath is caused by microbes devouring the left over micro particles of food. Less particles ==less bad breath."], "text_urls": [[], []], "score": [3, 3]}}, {"q_id": "6cpk5e", "category": "Repost", "title": "true north vs magnetic north?", "title_urls": {"url": []}, "selftext": "What is the difference between true north and magnetic north??", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhwe83u", "dhwe87v", "dhwef36"], "text": ["The geographic poles represent the axis on which the Earth rotates. The magnetic poles are the rough axis of the Earth's magnetic field, where the magnetic field points downward into the Earth. They are roughly aligned (close enough that a magnetic compass is relatively accurate in most places) but the magnetic poles move and meander around. 100 years ago the magnetic north pole was in northern Canada but it's been moving north towards Siberia; right now it's over the Arctic ocean", "true north is the north point of the axis the Earth rotates around. magnetic north is where your compass points. the 2 are not the same point. because the Magnetic pole is based off the movement of the earth's molten core.", "True north is the direction pointing straight to the point on the globe that the Earth rotates around. Magnetic north is pointing in the direction of the magnetic field. If you were to follow the needle on a compass you would not go in a completely straight line due to local variations in the magnetic field and you would end up somewhere in North Canada. Also the magnetic north pole and the magnetic south pole is not quite opposite of each other. And they are both moving around and can change quite a lot in a century. Magnetic north is used because it is very easy to find it as you can just use a simple magnetic compass but true north is used when you need accurate measurements that can be used decades later."], "text_urls": [[], [], []], "score": [6, 3, 3]}}, {"q_id": "6cqxrh", "category": "Repost", "title": "What is the definition of \"Natural Flavor\" and \"Natural Essence\" ingredients in food/drink and why can they be vague?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhwp4w2"], "text": ["They have no legal meaning. They're just there to trick you into thinking \"natural\" is like a magic healthy thing. Its just a marketing trick. You can stick it on anything you want."], "text_urls": [[]], "score": [3]}}, {"q_id": "6cr4e7", "category": "Repost", "title": "Why are flat head and Phillips head screws both so common? Why is there not one go-to standard?", "title_urls": {"url": []}, "selftext": "I understand the use of the other less common screws for various reasons - to avoid tampering or to avoid stripping, but why did no consensus ever form for the best \"standard\" screw to use. That way we'd need fewer screwdrivers!", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhwrouo", "dhwtjgm", "dhwtpn6", "dhwqz7z", "dhwte3e", "dhwslxe"], "text": ["Because flat and phillips are both garbage. The Robertson screw is the one you want my friend. Stays on the end of your bit, provides great grip, and attractive to boot.", "Flat head screws allow for more torque to be put on the screw head without stripping the screw but it is not self centering so it's harder to get the screwdriver centered on the screw and it is easier for the screwdriver to slip and fall off the screw. It is also possible to make a shallow screw head because a flat head slot isn't cut as deep. Phillips head or cross slotted screws are self centering meaning the screw driver is directed to the center of the screw making it easier to engage the screw. The phillips slots are not as wide though and the angle of the slots may not exactly match the angle of the screwdriver. These two factors make it easier to strip out a screw head under high torque. Because the screwdriver fits down into the cross slot the screw head must be deeper.", "Because no one head pattern is best for all sizes and purposes. Flat head is cheap and simple, but mechanicaly inferior, Philips automatically cams out, JIS doesn't, Torx handles higher torque, but is uncommon, etc.", "Flat heads were the standard for many years. (They were easy to make) Phillips came out later and are better. But there are many more out now. Torx, allen, star, etc....", "Philips were invented to cam out at a certain torque to prevent stripping the screw hole. I have a bit set with 100 different screw tips but my preference is for Torx.", "Everyone on Planet Earth already has screwdrivers for both. Any other new kind means you have to go out and buy another one for whatever wacky star/Robertson/Torq. Also, they are just fine for the vast majority of jobs. if is't not broken they don't fix it. The other's definitely aren't better enough to merit an overall change."], "text_urls": [[], [], [], [], [], []], "score": [18, 16, 6, 4, 4, 4]}}, {"q_id": "6cru8p", "category": "Repost", "title": "How does a dark room (for developing photographs) work.", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhwxwwa"], "text": ["In the dark room there is an enlarger. A negative is put into it. A bright light is shone through the negative onto light sensitive paper. The image is kept in focus. After the light sensitive paper is exposed to the image it is put through a series of trays of chemicals which develop the image and then the development is stopped or fixed. The paper is dried and the image on the paper is permanent."], "text_urls": [[]], "score": [5]}}, {"q_id": "6cu3ju", "category": "Repost", "title": "How do some people \"throw their voice\"?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhxfa50"], "text": ["Scooby Doo really confused me as a child when Shaggy \"threw his voice\" across the room to distract the monster. Humans cannot do this, it's impossible. A single directional speaker can, but we are like normal speakers and eminate sound waves in all directions from our mouths."], "text_urls": [[]], "score": [6]}}, {"q_id": "6cuct7", "category": "Repost", "title": "If mods can make video games look so much better, why are those not the graphics developers use at launch?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhxezpc", "dhxept5"], "text": ["- For multi-platform games, the development has to be done at the level of the least powerful system. - Graphical features that are buggy for some systems are sometimes just disabled outright, but can be re-enabled by mods for supported systems. - Capabilities that would normally require a licensing fee for a commercial release can be added by modders via a non-commercial license for free (very grey area). - The state of technology at the start of game development won't be as powerful as it will be at the end.", "Cost * time taken = profits If its not cost effective. Also they are selling to gamers with varying pc specs, if you release a game that runs well and looks fantastic on a high end system. But on a potato runs stuttery, then your reputation and the games reputation will be tarnished, and then harm future games by the studio."], "text_urls": [[], []], "score": [5, 3]}}, {"q_id": "6cv8my", "category": "Repost", "title": "What is inflation and why/how does it increase the value of a currency in the later years.", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhxm8ur"], "text": ["An oversimplification of inflation is that, over time, the value/purchasing power of a currency decreases while the cost of actual goods increases. It doesn't actually increase the value of a currency in later years. In fact its the opposite, inflation leads to a decrease in value of currency. There is a lot of different causes for inflation. One thing that could cause inflation is an increase in the amount of money that is being printed/that is in circulation. If you think about it, this makes sense. The more common of a thing there is, the less valuable it is. This also explains why when there is more money in circulation, the higher the price of goods. With an increase in purchasing power by consumers, companies increase prices to make more profit."], "text_urls": [[]], "score": [3]}}, {"q_id": "6cvf22", "category": "Repost", "title": "Jupiter's core is said to be \"Liquid Metallic Hydrogen/Helium\". How can hydrogen and helium be metallic?", "title_urls": {"url": []}, "selftext": "I think I might understand how at extreme pressures hydrogen and helium can't be gaseous despite the temperature, but what does being metallic mean? How is that possible?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhxnuhk", "dhxvvx3", "dhxont9"], "text": ["In this case \"metallic\" is in the physics sense of the word, in that they have high electron conductivity, high thermoconductivity and high density. It has to do with the EXTREME pressures involved, which causes hydrogen to break down from its normal molecular (H2) form and become atomic. Scientists were finally able to create it in the lab earlier this year. Previously it was theorized that it would take pressure of 25 gigapascals to make hydrogen metallic, in the end it actually took 495 gigapascals. You can read more about the discovery [Here] ( URL_0 )", "so what does being metallic mean, well in it's simplest form it means all the atoms share their electrons, instead of a normal covalent bond, where atoms share a few electrons between them, electrons in a metal have a sea of electrons, electrons can easily move from one atom to another, it's why they make such good conductors, add in an electron and it makes a wave that ripples through the electron sea and pops out an electron at the other end. it's like two or more people agreeing on a time share vs a hippy commune where anyone can come and go as they please from any house.", "Metallic hydrogen, what is it and how do they make it? - URL_0 Basically the pressure squeezes the hydrogen atoms into a different formation which is far denser than normal a bit like when Superman squeezes coal to form a diamond."], "text_urls": [["https://phys.org/news/2017-01-metallic-hydrogen-theory-reality.html"], [], ["https://www.youtube.com/watch?v=b-gCfHXNIVc"]], "score": [37, 5, 3]}}, {"q_id": "6cxuu4", "category": "Repost", "title": "Whats the point of having both flathead and phillips head screws?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhy7nr3"], "text": ["Phillips head are designed for the screwdriver to pop out of the screw if the torque is too great. This prevents screws from being over-tightened and damaging either the screw or the underlying material. Flatheads are simpler to make, and can be used when over-tightening isn't an issue. However, they suck for power tools, which tend to slip sideways out of the slot."], "text_urls": [[]], "score": [4]}}, {"q_id": "6cz0my", "category": "Repost", "title": "How do video game designers spend years making a video game without the game being technologically outdated by the time it's released?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhykrs7", "dhyilk8", "dhyhn9k"], "text": ["Most games (though for this discussion let's limit ourselves to what would traditionally be considered 'AAA' titles) really are technologically outdated at the time they are released. The reason why you don't notice is because you're comparing them against other games that were developed at more or less the same time. Obviously it's not as cut and dry as that though. Another commenter mentioned how developers will have targets for \"future mainstream technology\" that they go for and then ease back on if they overestimated the amount of improvement. This is also very true, and when you look at PC games it is more obvious how they can adjust quality in various aspects to suit more or less powerful hardware. Usually these are presented as graphical options that a player can adjust to suit their preferences/desired performance. Techniques also improve over time, but there are also well-known techniques that are extremely impressive but are expensive to use on current technology. For example, it is possible to implement \"perfect\" reflections and light scattering (for all intents\u200b and purposes), but the technological requirements for this are absurd when compared to what is currently common. Developers compromise by using imperfect approximations to gain performance. Incidentally, you will often see tech demos that bring into stark contrast the difference between recently released games and what is actually possible on similarly recent technology. This can be achieved by the smaller scope of what a tech demo requires, but it also comes out of the shorter development time and availability of more sophisticated techniques at the time development started.", "The state of the art at the time of release is other companies who have spent he same amount of time developing.", "They develop for where they think technology will be and then tweak it to fit the current tech when released. Notice how the early versions of games usually look better than the final release? They develop with top of the line equipment and then reduce for the common denominator."], "text_urls": [[], [], []], "score": [10, 3, 3]}}, {"q_id": "6d0t7k", "category": "Repost", "title": "Why is water so important for the search for life in the universe? Couldn't that just be how life on earth works? Similarly, why do we assume a planet can only be this \"goldilocks\" distance from a sun in order to support life?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhyvzt8", "dhywso1", "dhyz7xi"], "text": ["You have a good point. You can also ask what can be considered living. We only understand life as it is on earth. Thus we know wat we are looking for on these goldilocks planets. That being said, there may be an object in the middle of a planet that could be classified under our definition of living organisms. Those 7 characteristics of life. But we have no idea how other live an arise from something other that C, N, O and H molecules, and these molecules can only be used generally as animals on earth use it. Because of that we also know a certain temperature for these are needed with certain conditions. Thus we believe there is a bigger chance of finding life on planets with similar conditions. Hope this helps:)", "water is so important because its physical and chemical properties (acid-base buffer, high specific heat and many many others) making it as a perfect solution for complex organic compounds and maybe 'smart living organisms'. So, searching for water means you are searching for environments where simple structures can react in a friendly solution (ph ~7) and start forming more and more complex combinations, finally getting a way to store and releasing information (ARN like) or energy (citric acid cycle). I think, the key concept is \"searching for possible smart life\"... we already know \"tardigrades\" are living organisms than can live in outer space and really hostile environments (so this universe is full of life).", "Many good answers, but to add to the chemical/physical properties of water, another factor is that it reaches its highest density at 4\u00b0C as opposed to virtually everything else (correct me if I'm wrong) which has higher density in solid form (frozen). This allows solid water to float on comparatively warmer water and act as a buffer to the outside cold and allows life unter the ice to continue relatively unabated. It also means that eg. a lake freezes from top to bottom, so life can migrate towards the bottom during winter and stay safe. And as others have said, we look for a planet with our conditions because we know it works for life, we have basically no information on other conditions and life. With the billions of planets out there, we'd rather look for something we KNOW has the chance of life."], "text_urls": [[], [], []], "score": [7, 6, 3]}}, {"q_id": "6d16i4", "category": "Repost", "title": "What info can cookies access about me or my browsing history? (Other than the cookie's originating site login info)", "title_urls": {"url": []}, "selftext": "Say, can it know who I am based on my login at FB or Twitter? Or say, know what other sites I browse or what news articles I read? Or who I am logged in as in other websites?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhyybfe", "dhyy33d"], "text": ["Cookies are just a storage form that certain websites use. As such it can contain any information that the website thinks is necessary to record on them, including \"who\" you are so if you return they know you are the same computer as before and they can internally combine the information from before with the new one and as such build their knowledge of you. Other things they might record are for example your preferred settings to make it easier to browse their website.", "Cookies do not access info but rather hold info the website would like to access later. Most cookies cannot be read by other websites, only the site that created it. There are ads on sites that come from third party sites. Those can keep track of every site you visit."], "text_urls": [[], []], "score": [7, 3]}}, {"q_id": "6d1wa9", "category": "Repost", "title": "How do some music artists, like Five Finger Death Punch, become huge hits with their first album?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhz4jel"], "text": ["First and foremost you have to understand how the music industry works. If the label has a label-beneficial contract, which is common with a newly signed artist, and the musical style fits current trends, they will market the band as much as possible. Marketing includes grassroots, pushing rotations on radio, Spotify and Pandora as well as teaming a new artist with an established group for tours. Additionally, tv placements can be purchased. Building hype is easy with an unlimited budget, and most bands have a short popularity cycle so the record label will push hard to creat a buzz for them."], "text_urls": [[]], "score": [4]}}, {"q_id": "6d27km", "category": "Repost", "title": "what is meant by \"the notes you don't play\" when talking about jazz music?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhz6fg0"], "text": ["In jazz there's allot of timing and there are often Many instruments playing complex progressions at once. This said, when you listen to jazz there's allot going on for your ear to focus on so a musician can decide to pause, or play fewer notes. This would focus your ear to another set of instruments making the notes you don't play as powerful as the notes you play. (u/Nosvind opinion?)"], "text_urls": [[]], "score": [5]}}, {"q_id": "6d49ta", "category": "Repost", "title": "Why do we interpret spicy foods as 'hot' even though they are not hot in terms of temperature?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhzpu2e"], "text": ["Capsaicin is the name of the chemical in spicy food that makes it taste spicy - the more capsaicin, the spicier the food. The way that capsaicin works on us is that it binds to a specific taste receptor on our tongue, which sends a signal to our brain. By a neat coincidence, those receptors are actually meant to tell our brain how hot (temperature) our food is - it's a coincidence that it's also activated by capsaicin. So our brain recognizes the same sensation from \"hot\" peppers as it does from \"hot\" burning food, because our taste receptors don't know the difference. Fun fact: birds don't have those sorts of receptors, so they can't taste spiciness in foods. Peppers evolved to take advantage of that. Land animals would avoid the spicy peppers, and only birds would eat them. The birds would fly away and poop out the seeds somewhere far off, so that the pepper plants could spread over a wider area than if land animals ate their fruits and dropped seeds nearby."], "text_urls": [[]], "score": [4]}}, {"q_id": "6d4u96", "category": "Repost", "title": "If you are traveling in a plane against earths rotation, do you arrive at your destination sooner?", "title_urls": {"url": []}, "selftext": "As the titles states, if you are traveling against earths rotation in a plane/jet do you get to your destination any quicker? My mind says yes but their is a little voice telling me no. What's the answer and the logic behind it?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dhzvmsu", "dhzvq7v"], "text": ["The speed of the airplane is limited by the air resistance and speed of sound. When you specify the speed of an airplane it makes more sense to use the airspeed and not the ground speed. The air is influenced by the surrounding air, pressure differences due to weather patterns and the ground. And since the ground is moving with the earth rotation the air is also moving with the earth rotation. So an airplane going against the earth rotation will still go \"backwards\". However due to weather patterns and less influence from the ground on high altitude wind there is a series of \"jet currents\" which are fast high altitude winds traveling around the world. The airplanes can chose to fly with these winds to get more speed. Most air travel in the world in the 60 degree latitude which usually have a jet current going west to east. So a flight from New York to Paris tends to be faster then a flight from Paris to New York. However this does depend on the conditions and route on the day of the flight.", "You do get to your destination more quickly in one direction than the other, but as the other comment here stated, it's due to prevailing winds, not the Earth's rotation. The airplane is pushing itself through the air, and the atmosphere is moving with the Earth. So regardless of how the whole planet is moving, the airplane won't get from point A to B on the planet faster because of the rotation alone. Another way of thinking about this, is that one timezone is very roughly one hour's worth of Earth's rotation. If you were able to fly at that speed + the speed of the airplane, eastbound cross-USA travel would only take a couple hours, and that's definitely not the case. Another ANOTHER way of thinking about this, is that you can't travel from the east coast to the west coast by simply taking a hot air balloon straight up in the air and waiting 3-4 hours for the Earth to turn underneath you."], "text_urls": [[], []], "score": [5, 3]}}, {"q_id": "6d6j6p", "category": "Repost", "title": "Why is Citizen Kane considered such a masterpiece?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["di09glz", "di0aqqx"], "text": ["The cinematography was innovative. There were some average sized sets that look huge on camera. There were camera angles that were novel at the time. In the opening sequence, the lit window stays in the same place on the screen as the shot zoomed in with different pictures. These things might be trivial to do today, but it was groundbreaking at the time.", "One could call it the precursor of modern movies. Before citizen Kane, movies would only use 1 maybe two camera angles per scene. They where less like movies and more like recorded plays. Citizens Kane usage of multiple camera angles with many sets instantly set it apart from its predecessor. It's the same reason the model-T is amazing. Sure by today standards it's a relic, but it set the standard."], "text_urls": [[], []], "score": [4, 3]}}, {"q_id": "6d6rs5", "category": "Repost", "title": "If I picked up a young child, who weighs 50 pounds, why does it feel lighter than picking up a dumbbell of the same weight?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["di0c1y5", "di0bkjr", "di0cpj2", "di0bnaf", "di0o54m", "di0snbr", "di0r0vu"], "text": ["Similar question: URL_0 My answer from that thread: > Because the kid wants to be comfortable, and the water doesn't. > Deadweight, like the water, is harder to carry because it doesn't do anything like, say, maintain it's own center of gravity---or, in the case of an older kid, actually hold on to you, thus distributing the weight across more of your muscles. > As a result, you need to use your own power to do all the little things necessary to keep the weight oriented they way you want it to be oriented. That makes it seem heavier. The water might slosh around or get slightly off center from how you are carrying it some other way, and you then have to consciously or sub-consciously correct it. The kid, on the other hand, probably wants to stay generally upright and generally in the same place/orientation as after you lifted them, taking that pressure off.* > *assuming not a toddler. Their weight is effectively quintupled from sheer madness.", "I believe it's because children have a natural ability to distribute their weight in such a way that's optimal for the person picking them up and that's why it's equally difficult to handle them if they go deadweight on you.", "Your brain considers both weight and size. Try this experiment. Find something small that is super heavy for its size. Pick it up. Then put that weight in a big box, and pick that up. It will feel much lighter. Your brain is saying to itself, \"Wow that's not so heavy for something of this size,\" even though it's the same weight you just lifted. By the way, I agree with the stuff about live weight versus dead weight as well", "Because of the weight distribution, when you're holding a child your bringing it closer to your center of gravity, and making your body more stable this stability allows for less work to be done in muscles of your body . If you were to hold the child like you hold a dumbbell you would find that they feel about the same. This is the same reason why grocery bags feel insanely heavy, because often times you're holding them at an awkward angle away from your center of gravity. Read more here Source: URL_0", "Are you truly concerned with picking up the weight as much as holding the weight because there is a difference? And the method of picking up the weight will make a big difference. * If you pick the up either the child or dumbbell with extended arms and hands it will seem to weight more than if you picked it up by hugging it. Hugging it has less impact on your arms and hands. * If you pick the up either the child or dumbbell with either extended arms and hands or by hugging it will seem lighter if you stoop down with bended knees than if you were bent over at the waist. Thus more parts of your body help to lift the weight. * As a tall slender mass, the child's weight is unevenly distributed, with the bulk of it in the torso, and can help support and balance his/her own weight, unlike a dumbbell of equal weight that is compact and is unable to help support its own weight. * The child is a tall slender object that can be held snug to your body with your arms wrapped around the child, which makes supporting the weight easier than holding in equal weight in a different shaped mass in your extended hands. And the child can hug you to help support the weight. * If you carried the child on your shoulder or back he or she would seem even lighter because doing so makes the child's weight part of your own weight and balance system.", "Lots of good answers, but none seem to have mentioned an important factor: isolation. When you do a bicep curl with a dumbbell, good form helps you use only your bicep, so you can specifically challenge that muscle. You intentionally minimize involvement of your triceps, pecs, delts, etc. Similarly for most other simple free weight motions. When you reach down to pick up a child, you're making a complex movement and aren't intentionally isolating any one muscle. You recruit a bunch of muscle groups to share the load, and it feels easier. Unless it's an angry toddler - then their bones just turn to jelly and suddenly all their squirmy uneven weight is focused on a muscle you didn't know you needed!", "Because when you pick up a child who weighs that much, they usually have the motor skills to distribute their weight and \"participate\" in the lift. Think of ballerinas who get lifted up by their partners; they're moving with the person lifting them, which reduces the amount of effort the lifter needs to exert to get them off the ground. A child you're picking up will move with you and push off as you lift, so you're not using just your own strength to lift them up. A dumbbell can't do that."], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/38yxi4/eli5_why_does_carrying_40_pounds_of_water_feel/"], [], [], ["http://www.animatorisland.com/principles-of-animation-physics-part-4/"], [], [], []], "score": [262, 28, 20, 12, 11, 10, 5]}}, {"q_id": "6d7ttx", "category": "Repost", "title": "How iPhone home button recognizes my fingerprint when it does not have infrared or sensor or camera", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["di0kdmd"], "text": ["The button *is* the sensor. See this paragraph from Wikipedia: > Touch ID is built into the home button, which is built of laser-cut[9] sapphire crystal, which does not scratch easily (scratching would prevent Touch ID from working).[10] It features a stainless steel detection ring to detect the user's finger without pressing it. The feature does not work without contact with this ring. There is no longer a rounded square icon in the home button, nor is it concave. The sensor uses capacitive touch to detect the user's fingerprint.[10] The sensor has a thickness of 170 \u00b5m, with 500 pixels per inch resolution. The user's finger can be oriented in any direction and it will still be read.[2] Apple says it can read sub-epidermal skin layers,[11] and it will be easy to set up and will improve with every use.[9] The sensor passes a small current through one's finger to create a \"fingerprint map\" of the user's dermis. Up to 5 fingerprint maps can be stored in the Secure Enclave. URL_0"], "text_urls": [["https://en.wikipedia.org/wiki/Touch_ID"]], "score": [235]}}, {"q_id": "6d943m", "category": "Repost", "title": "How do ISPs work?", "title_urls": {"url": []}, "selftext": "Something I've pondered for awhile. How do ISPs work? I know the internet basically works by sending a signal from my PC to another PC (Read: A server), but where do ISPs factor into all this? How and why do our signals have to go through them?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["di0t6f2", "di0u6cc", "di0suvy"], "text": ["I explained this to my 6 year old like two days ago, that seems close enough: Every device that connects to the internet is part of a network, the computer in your house is part of the local network in your house, the website you're trying to reach is on a computer that's on another network in someone elses house (or business premises). But for those two computers to talk to each other and show you their website, the two networks need to talk to each other. So, your ISP has their own network. You connect your network to theirs, then they connect their network to someone elses, then they'll connect on to someone else. This keeps going, all of the different networks come together making paths that let you get from your computer at home to the one that has your website somewhere else. ISPs provide the door out to the bigger networks from your house. The internet is just lots of networks coming together and ISPs let you join that network. Obviously it's not as straightforward as that. But that kept the 6 year old happy, covered the basics and makes a good starting point I think. My younger brother never quite understood it that way though. So when I explained it to him I went with this: You want to send a parcel to someone in another city. But it's huge, needs a truck and has to be collected from your door and delivered to their door. It'll go down the road outside your house, then it'll join the bigger road at the end of the street, then it'll get on a highway and head to whatever city it needs to go to, come off the highway on to the mail road, then back onto their street and finally down the road to their door. The only problem is, you don't have a road to your door. So you call up your ISP, they come out and build a road that lets you get from your door to the bigger network of roads that'll let the parcel go to where you're sending it.", "So first off, ISPs exist to provide you access to the Internet. The Internet is a huge network, or even better a network of networks, which interconnects all kind of networks, from home networks (computer+smartphone, for example) to corporate networks and so on. Now, there are literally billions of devices connected to the Internet, and you'd like to be able to send signals (data) to any of them, from a smartphone in Texas to a huge server in < random country > . Without ISPs, you'd had to establish physical connections with literally every such device, either by laying cables or by installing huge antennas, repeaters, etc. in the entire world. Then anybody else would have to do the same. What's more, when a new device appears (in any part of the world), you'd have to go there and connect your cables or repeaters to that device. **It would be a huge, unfeasible mess**, not to mention extremely expensive. This is where ISPs step in. ISPs literally provide you access to the Internet. Take for example a local ISP, which only serves one city. This ISP connects all the devices in your city, which you couldn't really do yourself in a simple way for the reasons I mentioned above. Now assume that lots of cities had their own local ISP( or ISPs), but they weren't interconnected. If you were in LA, you could talk to your friend in LA (basically by sending your signals to some routers of the ISP which forward them to your friend), but not to another friend in San Francisco, not mention Anchorage, Tokyo and so on. That's bad =( So you need to interconnect local ISPs worldwide. How do you do that? Again, there are millions of cities in the world and each of these ISPs would have to connect to millions of other ISPs in the whole world. Just think about a small ISP in Oregon laying underwater cables to reach an ISP in Shanghai. It would still be crazy. This kind of reasoning eventually leads to the modern structure of the Internet, which includes: - very few Tier 1 ISPs, acting globally and interconected; - some (thousands of) regional ISPs, acting more or less at a state/country level, which are interconnected to their own Tier 1 ISPs and to *some* other regional ISPs (e.g. California ISP may be directly connected to Nevada ISP but not to Germany); - some (hundreds of thousands/millions of) local ISPs, acting more or less at a district/city level, which are connected to their regional ISPs; - some billions of devices, connected only to their local ISPs. Now, local/regional/global ISPs don't have to be different companies. In fact, lots of local ISPs are actually branches of the huge network of a regional ISP, which in some cases may be \"simply\" a branch of the network of a global ISP (like AT & T).", "ISPs provide connections from your house to the grid. They charge for the usage of this grid. The grid is maintained partially at their expense."], "text_urls": [[], [], []], "score": [16, 4, 3]}}, {"q_id": "6d9jhk", "category": "Repost", "title": "How did people in the Stone Age deal with diseases (viruses, bacteria, parasites)?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["di0vi04"], "text": ["> How did people in the Stone Age deal with diseases and mental disorders? They either got over it, lived with it, or died. People died a lot back then. > Wouldn't they have died out at a certain time? Individuals did but overall they reproduced more. > Considering countries today are very developed and still thousands of people die out from a virus in developed countries how did people in the Stone Age cope? Wouldn't they all have died out? They didn't live nearly as close together back then. Even if an isolated tribe or family group caught some terrible sickness they would just all die and maybe never be found by other humans. This tended to weed out illnesses that were incredibly fatal and left those which were highly contagious but didn't actually kill their victims. Being too deadly would limit the survival potential of the illness itself."], "text_urls": [[]], "score": [6]}}, {"q_id": "6db4qp", "category": "Repost", "title": "What makes cancer so difficult to cure?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["di18r4z"], "text": ["Cancer is difficult to cure because it is a mutation of our *own cells*, not a foreign virus or bacteria that is infecting us. Anything that affects cancer cells will also affect our own healthy cells, which is why cancer treatments generally have very debilitating side affects, like hair loss, nausea, and much worse. It is difficult to strike a balance between how much treatment is needed to stop the growth of the cancer, and how much treatment the patient's body can even handle. Cancer can also be anywhere we have cells. It can be inside our organs. It can be floating around in our blood. Many cancer treatment methods require very precise targeting to limit damage to healthy cells. However, depending on the location of the cancer this may be extremely difficult or impossible."], "text_urls": [[]], "score": [6]}}, {"q_id": "6dbiu8", "category": "Repost", "title": "Why does time \"fly\" when we're having fun?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["di1g10g", "di1g9xz"], "text": ["\"When you are courting a nice girl an hour seems like a second. When you sit on a red-hot cinder a second seems like an hour. That's relativity.\" - Albert Einstein", "Because you're not focused on what time it is. When you're in class and you're watching the clock every 5 minutes, you're constantly reminding yourself of the time. When you're having fun, your focus is not on a clock."], "text_urls": [[], []], "score": [8, 6]}}, {"q_id": "6dg2go", "category": "Repost", "title": "We have a dominant hand, dominant foot and a dominate eye, but do we also have a dominant ear?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["di2codp", "di2cva4", "di2tv0g"], "text": ["I do. My left one can hear way better than the other because my brain chooses to listen to it more. And because I busted my eardrum when I was 12 and had ooze leak out of it", "I'm not sure, but I once heard that our left ear is better at receiving sounds, while our right ear is better at picking words. Edit: second part had \"left\" by mistake. Changed to right", "Because one ear will pick up sound and the other will pick up the reflection, it temporarily becomes dominant but they're built the exact same unless you have a small defect in one such as the hairs being damaged then the other one would become dominant slightly. Source: studying audio engineer"], "text_urls": [[], [], []], "score": [11, 8, 4]}}, {"q_id": "6dhba3", "category": "Repost", "title": "What is money laundering exactly?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["di2lx4g", "di2m2x4"], "text": ["Money laundering is taking illegally obtained money (say from bribes, or from drug dealing) and funneling it through legitimate businesses to account for the extra income for tax/legal purposes, making it harder for law authorities to figure out that you're getting the money illegally. If on paper your job nets you $50,000 a year, but then you outright buy a million dollar house, that raises flags. However if you own, say, a restaurant then you can do some creative bookkeeping to overrepresent the amount of money the restaurant is pulling in and thus explain where your income stream is coming from.", "So imagine you've done a bank heist. You've stolen a bunch of cash. Problem is, that cash is \"dirty\". It's linked to the bank you heisted, which means there is a potential that you could be connected to the heist by the law enforcement. So what you do is you send that money through a series of front businesses, each of which adds an extra layer of concealment as to the true origin of the monies. Traditionally, before the wiespread use of credit cards/electronic money transfers, the money you stole would have been hard cash. This meant your front companies had to be cash-based businesses. Launderettes fit this bill perfectly. This, combined with the idea of \"cleaning\" the monies, led to the term \"Money Laundering\" coming about. Nowadays, most money is \"stored\" electronically, so this requirement of a cash-based business is not so necessary. Fronts can now be, e.g., banks. There are many specific ways in which money can be laundered, but this is the basic principle."], "text_urls": [[], []], "score": [3, 3]}}, {"q_id": "6di0ys", "category": "Repost", "title": "the similarities and differences between socialism and communism", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["di2sovs", "di2uolt"], "text": ["Communism is state ownership of the means of production while socialism is the social ownership of the means of production. The difference is in where the power, control and consent lay.", "These names have been appropriated for different things. In Marxit doctrine, Socialism is the proletariat dictatorship meant to rebuild capitalist society. The end of that is the state being dissolved and society moving on without it, and that is Communism."], "text_urls": [[], []], "score": [4, 3]}}, {"q_id": "6djebf", "category": "Repost", "title": "Why does the the human mind ignore the second \u201cthe\u201d?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["di39fd2", "di374zb", "di39olv", "di3dhp7", "di37e9w", "di37l5o", "di3dq6w", "di3cxrp", "di3ezw6"], "text": ["The human mind ignores many many things actually. If it didn't, your consciousness would be constantly awash in so much information you'd basically be catatonic or hallucinating constantly. Our brains have evolved to tune in on a certain spectrum of reality and ignore a lot of it in order to function in an extremely complicated and ever changing world.", "Conditioning. I had to read that sentence three times before I noticed. You've been taught your whole life the correct structures of simple sentences, and your mind knows what that sentence is supposed to say. So when you read that, your mind ignores the second \"the\" because it knows it shouldn't be there and that it's unimportant to the sentence. Edit: easily the most popular comment I've ever made", "Similar to scrambled words... Aoccdrnig to rscheearch at Cmabrigde Uinervtisy, it deosn't mttaer in waht oredr the ltteers in a wrod are, the olny iprmoetnt tihng is taht the frist and lsat ltteer be at the rghit pclae. The rset can be a toatl mses and you can sitll raed it wouthit a porbelm.", "It's all about how the the brain works. The mind is conditioned to ignore the the second one because it is irrelevant to the the content. Like someone below demonstrated, it also works with scrambled words, because the the mind is very powerful. Your mind likes to be efficient. It's also the the same reason why optical illusions work. It constantly adjusts how it processes its surroundings based on the the input of the the environment. This youtube video from one of my favorite channels shows a good demonstration of your brain doing similar processes: URL_0 As you see in the the video, you brain can do weird stuff. Also, I doubled the the word ------\"the\"----- 9 times during this post. Did you notice all of it? ;)", "Learning. I learned to skim read when young so that i could pick out the important information from each paragraph. In this sentence the fact that there's a redundant 'the' is irrelevant to the sentence and so gets ignored when skim reading", "You're brain operates by following patterns. When you're reading a word, your brain looks at the letters all at once, not sequentially, so it can identify the word very easily even if certain letters are switched. It works the same way for sentences. Your brain takes the entire sentence and analyzes as much as possible at once.", "FYI - drunk me didn't ignore it. Read the first 4 words 5 times before the rest of it made sense. Also took ages to write this.", "For many applications the brain can be assumed to be a Baysian decision making system. This means that Bayes law can be applied (from probability class). Essentially the important bit is that what you end up inferring is proportional to the distribution you expect to see and what you actually see taking into account errors in the eyes. The eyes and the part of the brain that process the input to the eyes actually have a lot more error than you'd expect but you don't notice because of this mechanism (you gather more evidence over time, you ignore a lot of what you see the first time and retroactively try to remember if you later need to know). what you are expecting is something you develop over your life and in the case of 'the the' there are very small error bounds. This means when forced to make a binary choice you tend to go with the one you expect but you might feel there is something wrong with the sentence - that you struggle to identify. This is because the disparity between what you see and expect leads to large error bounds in the final inferred interpretation.", "This is a word by word repost. Here are the best 2 (IMHO) responses from the original [question]( URL_4 ): [Answer]( URL_2 ) by /u/TyrannicalDuck > Edit: For those of you requiring an extra \"the\" in my comment, you'll find it up here: \"the the\" > In addition to what others have said, the human brain, when reading, doesn't actually see every word, unless you're not fluent in a particular language. Your eyes actually take in multiple words at a time and parse the sentence based on the words you've taken in. This also means that unless a particular particle is deadly important to the sentence, your brain ignores it. It also partially explains why you sometimes go back over a sentence if it doesn't parse correctly. An extra \"the\" doesn't change the meaning of a sentence, so you continue as if you understood. > (Edit: some source for those interested in how reading works: URL_5 and of course this page has a nice, long reading list of sources at the bottom) > My question would be to those people who read languages such as Chinese or Korean or Japanese: does the same thing happen if you put two of the same particle in a row in a sentence? For example, would a Japanese person reading \"\u82f1\u8a9e \u304c\u304c \u308f\u304b\u308a\u307e\u305b\u3093\" spot the mistake or gloss over it in the same way native English speakers gloss over superfluous incidents of \"the\"? > Edit: it's curious and interesting as hell: about an equal number of native Japanese speakers gloss over the mistake as much as stands out for the others. If anyone has any research on reading and word cognition in non-roman alphabetic languages, I'd love to read it. > Edit2: As others have mentioned, the eye's saccadic movement system also has a lot to do with this. This wiki page has more information about it for those who are interested: URL_3 [Answer]( URL_1 ) by /u/tsuunga : > There's a phenomenon called [attentional blink]( URL_0 ) where, when you're rapidly presented with stimuli, your brain will perceive two identical stimuli in a row as a single stimulus. Basically, your brain sees \"the the\" and assumes there was only one. > In nature, identical stimuli in rapid succession are vanishingly rare - if you see two crouching tigers from the same angle and in the same position in a quarter of a second, it's much more likely there was only one tiger and you just blinked; so your brain edits your perceptions with that in mind."], "text_urls": [[], [], [], ["https://www.youtube.com/watch?v=0NPH_udOOek"], [], [], [], [], ["https://en.wikipedia.org/wiki/Attentional_blink", "https://www.reddit.com/r/explainlikeimfive/comments/3ze4ca/eli5_why_does_the_the_human_mind_ignore_the/cyldsj7/", "https://www.reddit.com/r/explainlikeimfive/comments/3ze4ca/eli5_why_does_the_the_human_mind_ignore_the/cylgmby/", "https://en.wikipedia.org/wiki/Eye_movement_in_language_reading", "https://www.reddit.com/r/explainlikeimfive/comments/3ze4ca/eli5_why_does_the_the_human_mind_ignore_the/", "https://en.wikipedia.org/wiki/Reading_%28process%29"]], "score": [394, 344, 304, 30, 25, 11, 8, 5, 5]}}, {"q_id": "6djxxt", "category": "Repost", "title": "What did Descartes mean when he said \"Cogito ergo sum\" or \"I think therefore I am\"?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["di38f1c"], "text": ["He recognized that he couldn't know the real world, only his perception of it. All he could know for sure was that he could think, but thought alone proved his existence, as that did not rely on perception (which might be false)."], "text_urls": [[]], "score": [6]}}, {"q_id": "6dl5v1", "category": "Repost", "title": "It takes some countries many years to develop nuclear weapons and many of them still fail. With the science behind such things so readily available, why is it still hard for them to develop such weapons?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["di3i7rh"], "text": ["The physics is pretty well understood. The engineering is *fucking hard*. With a conventional weapon, you take a bunch of explody stuff and pack it into a casing with maybe some chunks of shrapnel or anthrax dust or pig fat or whatever around it if you really want to be a dick about killing people. With a nuclear weapon, you have to make a complex device that takes a little chunk of a really hard to make substance and implodes a bunch of another hard to make substance around it *just right* to get the atoms in the material to start splitting before the regular explody stuff finishes destroying it all. If *anything* goes wrong, it's just a bunch of radioactive dust and a bang you could have got for $500 in dynamite and the cost of an empty rain barrel and a trebuchet. Add to that the fact that most of the countries that *have* the technology don't want anyone else getting it, and take every possible measure to fuck up the entire day of anyone who even tries."], "text_urls": [[]], "score": [5]}}, {"q_id": "6dlnsg", "category": "Repost", "title": "how does the sun keep burning. Don't fires die without oxygen and since there is no oxygen in space what keeps it alive?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["di3m6j7", "di3m6yp"], "text": ["The Sun does not \"burn\", like we think of logs in a fire or paper burning. The Sun glows because it is a very big ball of gas, and a process called nuclear fusion is taking place in its core. ... Hydrogen really doesn't burn, it fuses, into helium. So no oxygen is required. [source ]( URL_0 )", "It's a misconception that the sun is a ball of fire. Basically, the core of the sun is full of hydrogen atoms. When two atoms collide, they fuse together, combining their protons and neutrons to make helium. This process is called fusion. ~~In chemistry, whenever two things combine to make one thing they (usually)~~ When two hydrogen atoms combine they release energy. This energy is the heat and radiation from the sun. So, there is no \"fire\", but rather raw nuclear power."], "text_urls": [["https://starchild.gsfc.nasa.gov/docs/StarChild/questions/question36.html"], []], "score": [5, 5]}}, {"q_id": "6dmi6k", "category": "Repost", "title": "How is it that being able to pass a top secret security clearance test isn't part of the process of running for president?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["di3vmbb"], "text": ["> I'm genuinely curious as to how this isn't part of the process. Is there any test at all? This is a simple necessity of a democratic style of governance. If you create a process by which an entity must approve of a candidate before they can be elected, then that entity actually is in charge of who gets the position, not the people. This is especially true if those criteria are opaque to public scrutiny or subject to judgment calls; we might easily say that requiring presidential candidates to be 35 or older because everyone can tell if that is true or not, but identifying a security risk isn't something that the public may even be allowed to know the reasons behind."], "text_urls": [[]], "score": [4]}}, {"q_id": "6dmzek", "category": "Repost", "title": "Why do different months last a different number of days? Why aren't they all the same length?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["di3v41o"], "text": ["A year is 365.25 days long which is how long it takes to orbit the sun. 365 is not divisible by many things, just 73 and 5. Therefore if you must have equal months and for them to fit neatly into a year you either need 73 months of 5 days or 5 months of 73 days. Months are roughly based on moon cycles which are about 30 days long. (29.5 days, I think, based on the Chinese calendar)."], "text_urls": [[]], "score": [7]}}, {"q_id": "6dn905", "category": "Repost", "title": "If illegal content is so easy to find on the internet, how does it not get taken down by authorities?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["di3wrol"], "text": ["First, they have to find the physical address of the location that is hosting the site. Then, they have to determine if they have jurisdiction in that city/county/district/state/country. Many of these \"illegal\" sites operate of out countries that have very lax laws regarding content on the internet. Take The Pirate Bay, for example. It's moved from Denmark to Australia to Russia to Sweden, all over the place. No particular country has ever held on to them long enough to finish a lawsuit against them. And because they don't actually host the illegal material (they just provide links to illegal material), they can't really be prosecuted in many places. Using all these loopholes it's really easy to keep a site online. And even if a country does manage to get the site taken down by raiding the server's location with police, the sites generally all have dozens of mirrors (identical sites) that will continue to operate, so taking the primary site down doesn't even really matter. \"Black markets\" aren't illegal, they just sometimes deal in illegal goods or services. You can't take down Wal-Greens because someone likes to sell pot there, you can only take down the guy selling the pot. Some of these sites *have* been taken offline (even ones deeply hidden in onion servers), but only when the host of the site is profiting from the illegal material on his site."], "text_urls": [[]], "score": [9]}}, {"q_id": "6dne4x", "category": "Repost", "title": "Why are ruins and ancient building always so far under ground?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["di3xkwp"], "text": ["Because the ones that aren't buried underground were eroded away by wind and rain and plants and animals and people, so there would be nothing left to find. It isn't that ancient buildings always get buried. It is that the only ruins we can find are the ones that happened to get buried. Same thing with fossils. Not every single dinosaur turned into a fossil - it is a very rare event for any creature to become fossilized. It is simply that the dinosaurs that weren't fossilized are long gone, without any trace to be found."], "text_urls": [[]], "score": [5]}}, {"q_id": "6dovtk", "category": "Repost", "title": "Why did we choose 360 degrees to represent a circle over other numbers?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["di4965m"], "text": ["We get this from the Babylonians, who used a base-60 counting system. In that system, 6x60 was a much more natural-sounding number, the same way today we think of dividing money into tenths and halves as a natural way to do it. 60 was their base, and 6 is because a lot of their early study of circles involved hexagons (which is 6 \"radiuses\" in circumference). We see the same 60 division in hour and minutes because of this origin, too. Part of why it stuck around, is, as others said, that 360 is also conveniently divisible by lots of numbers (2, 3, 4, 5, 6, 8, 9, 10, 12, 15, 16, etc...)."], "text_urls": [[]], "score": [6]}}, {"q_id": "6dqgwo", "category": "Repost", "title": "How do places enforce bans on individuals?", "title_urls": {"url": []}, "selftext": "People get banned from places for various reasons, but how can a place like Disneyland, Yankee Stadium, or even the local Walmart hope to keep banned individuals from getting back in? Is the ban purely out of principle letting that person know they are not welcome? Or are there actually methods to keeping those people out? Have you ever been banned from somewhere?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["di4lojc", "di4lrhz"], "text": ["So, someone misbehaves someplace. They are told they are banned, and then kicked out. So, what does banned mean? Well, the ban is actually a trespass warning. So, if the person comes back and misbehaves, they won't just be thrown out -- they'll be turned over to the police, who will arrest them for trespassing. And since the place can show they've told the person never to come back, it's pretty much slam dunk that the person will be convicted of the crime, and spend some time in jail. \"Hmm... I could go back to that Walmart. They probably won't notice me... but it's not worth a jail sentence.\"", "There are technical problems with banning people as you may not recognize them when they enter again. If you do catch people trying to enter somewhere they are banned you might be able to charge them with trespassing but it would be hard on its own. So banning people are mostly out of principle. However the casino business have had issues with people who are able to play certain games so well that they are winning money. At that point the casinos will ban them and have systems in place that will recognize you as you enter the door. But there are few other places with similar issues."], "text_urls": [[], []], "score": [5, 3]}}, {"q_id": "6dt4um", "category": "Repost", "title": "Why do different countries have different power outlets? Why isn't there one universal one?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["di57p52", "di560ck"], "text": ["You'd also have to agree on a universal voltage at the same time, since you can only imagine the problems it would cause if there were different voltages on the same socket type. I'm from the UK and am also familiar with the plugs used in Europe and South Africa, but when I visited the USA I was shocked by how flimsy the US plugs and sockets are by comparison, particularly since they have to carry double the current to deliver the same power (since the voltage is halfed).", "A lot of different countries develop differently. Different plugs originate based on needs such as voltage, introduction of ground pins, etc. Plus it's not like at the very beginning that countries would talk to get this universal considering its mostly electric companies. In any case, different outlets and plugs were developed for different needs at different times whether it be to increase safety or modify voltage carried. Of course, it's difficult and timely to remove obsolete or older outlets and remove them completely especially when it's already so widespread so that explains why there are so many types. However as to why there isn't a universal one, it's difficult to implement. Countries and companies have to agree and the work needed is immense. Imagine taking all the outlets in a country where most chargers and plugs fit already and changing it to the universal standard. So many different companies will have to create new products or modify old ones and then customers have to buy them. It's not quick or easy. It's failed many times due to its negative impact on consumers and the economy. It's just too financially crippling and time consuming. I'm sure you know some people who own some electronics that are decades old and refuse to upgrade and if the outlet were to change, it'd force them to buy new ones since companies sure won't provide a new part for such an old technology. Even in your everyday life, imagine needing to buy a new cable or entirely new hardware for your stove, fridge, washer, dryer, dishwasher, laptop, phone, microwave, hair dryer, curler, straightener, razor, clock, etc. It already sounds terrible, right?"], "text_urls": [[], []], "score": [3, 3]}}, {"q_id": "6dv2gw", "category": "Repost", "title": "Why does it feel colder when the air is moving?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["di5kxva"], "text": ["We always have some amount of moisture on our skin, whether or not we are noticeably sweating. This moisture evaporates and cools us down. We feel cool because the water, which requires energy to change from liquid to gas, takes energy from the surroundings when it evaporates. In this case, the surroundings include our skin. Moving air causes water to evaporate more quickly. Everybody has, at some time or another, blown on something to dry it off. Speeding up the process of evaporation means more energy is more quickly transferred from the skin to the water."], "text_urls": [[]], "score": [3]}}, {"q_id": "6e2qc1", "category": "Repost", "title": "Why the lowest temperature possible is 0 Kelvin (273 Celcius), but the highest temperature ever recorded 4 trillion degrees Celsius", "title_urls": {"url": []}, "selftext": "why is (minus) 4 trillion degrees Celsius is not possible", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["di77hhk"], "text": ["In the words of a great scientist named Richard Feynman, temperature tells you how much the atoms around you are jiggling. Everything jiggles. Atoms that jiggle slow feel cold and aims that jiggle fast feel hot. So the coldest it can be is when all the jiggling stops. That is absolute zero. Then from there you can add more and more energy and get the atoms jiggling faster and faster, and call it whatever number you want based on our arbitrary scales. So why the temperature where water boils is called 100 in one scale and 212 on another is completely irrelevant, but absolute zero is a definite thing. The world on the atomic scale, however, is a mess of roiling energy. Any atoms really at absolute zero would actually get constant little nudges from tiny bits of energy moving all around, and they would jiggle some because of it."], "text_urls": [[]], "score": [10]}}, {"q_id": "6e48jl", "category": "Repost", "title": "How would basic income work if everyone received a living income from the government, and no one wanted to work anymore?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["di7i2ln", "di7ibhz"], "text": ["You'd have to work to buy things, cell phones, internet, other luxury items. I imagine it being issued like an ebt or food stamp card. Rent, food, transportation, medical, those would accept the card. Couldn't buy booze or weed with it, though.", "That's not exactly how it would work, sure some people would try it, but the idea of a basic income is that it is just enough to cover necessities, housing, food, utilities, ect. Anything else, like transportation costs, property taxes, internet and phone service, probably child care, basically any other incurred expenses would come out of your own pocket. If you feel like you can live just a very basic life style, you wouldn't have to work, unless some kind of part time employment was a prerequisite for getting basic."], "text_urls": [[], []], "score": [8, 3]}}, {"q_id": "6e54ri", "category": "Repost", "title": "Why does tickling cause laughter?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["di7t45z", "di7t4jx", "di7wijp"], "text": ["Tickling that causes laughter can be caused by touching several sensitive spots, such as armpits or the neck, which are \"hidden\" or otherwise vulnerable parts of us. The somatosensory cortex of the brain is responsible for picking up these touch signals, and sending them to the cingulate cortex, which makes sense of them. Laughter is genetically meant to be some sort of a defense mechanism; we're programmed to think that when someone touches these sensitive spots on our body, that it will cause some sort of harm to us. Keep in mind, our body systems still function in a primitive manner: to ensure survival. When the touch signal is basically harmless, signals are sent back to the sensory cortex, to evoke laughter, which is practically a \"false alarm\" sign that nothing was wrong, to decrease any form of stress. The old, primitive reason of laughter is to provide a relieving sense. Which is why comedy, involving unexpected jokes and one liners, makes people laugh.", "I seem to remember reading somewhere about how being ticklish on certain parts of your body (belly, neck, armpits, etc) was actually an evolutionary thing that developed to teach children to learn how to protect their vulnerable spots on their bodies. I dont know if that's true or not, or if that explains the laughing part, but it makes sense to me. It's like, our bodies made it fun to learn basic self defense when we're young or something", "If you tickle yourself, it doesn't tickle, as we all know. That is because you are prepared for where it will happen. The interesting thing is that if you guide someone else's hands over you to tickle you, it will also not tickle for the same reason."], "text_urls": [[], [], []], "score": [151, 24, 6]}}, {"q_id": "6e5ji2", "category": "Repost", "title": ". Why when you sunburn your skin does it stay warm for a few days after? Surely bloodflow /sweat will cool it down quite quickly? Why does it keep burning?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["di7t1nb", "di85qgh"], "text": ["The hot, red skin from a sunburn isn't from it getting hot and needing to be cooled down. Sunburn is caused when UV rays damage the DNA of your skin cells. This results in inflammation as your blood vessels swell to provide better access for your immune system to carry away the damaged cells. The extra blood to the region makes it warmer and redder than usual. And the swelling makes it extra sensitive to touch.", "Physiologist here: Short answer: inflammation. When you sunburn your skin, you injure it, and kill some skin cells. Your body responds with an inflammatory response, and one result of inflammation is increased blood flow to the area of inflammation. This results in both the red color that is seen and the sensation of heat."], "text_urls": [[], []], "score": [22, 7]}}, {"q_id": "6e6u1j", "category": "Repost", "title": "Why do we make cars that easily go way faster than the speed limit?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["di80rr6", "di82xo1", "di8cnz8", "di8a17d"], "text": ["Well, all countries have different rules, the same goes for speed limits! The best example is Germany, they are known to have roads with NO speedlimit, meaning you can go as fast as your car (and your bravery) will take you!. That also explains why there are many sports cars in that country too. How about other countries with speed limits?, well to be honest. People who buy such cars just do it because....well they can! Think of it as a show of status rather than practicality. Its like why people buy virtual clothes or cosmetics. Theres no advantage to getting them, the only difference is that you are now seen as a richer person!", "Besides all the reasons already posted, it's simply much more energy-efficient and economic. An internal combustion engine is most fuel-efficient at around 1,500-2,000 RPM, but is capable of safely hitting several thousand RPM higher as well. So you want your typical highway speed to be around those efficient RPMs which means the vehicle must also be capable of greater speed.", "The energy from a car's engine goes three places-- making the car go faster, overcoming drag, and making the car go uphill. Drag is proportional to speed, so if you made a car with an engine that's only powerful enough to overcome drag at 70 mph, then at 60mph it will be using almost all of its energy overcome drag, and won't have much left over to make the car go faster. So it will won't be able to accelerate from 60 to 70 in a reasonable time. Then, if all of the energy is used to overcome drag at 70 mph, it won't have any energy available to overcome even the slightest incline, and will have to slow down considerably to go up a hill. tl;dr If a car only has enough power to go a normal speed limit, it doesn't have enough power to accelerate quickly or go uphill.", "The market demands performance on demand. People want to accelerate quickly. In order to accommodate that, the industry fits cars with powerful engines. The market also demands fuel economy. To facilitate that, the industry fits cars with transmissions with tall gear ratios or overdrive. These ratios mean you can maintain speed at a low engine RPM. It also means at high RPM, the car could theoretically go very fast. The combination of the two mean cars can accelerate quickly and they have the power to actually physically achieve high RPM at tall gear ratios. Why don't they limit the speed? Because they don't have to! There's no law, like in Japan, that requires a speed limiter. That would be one more part, which costs that much more to make the car, that has to be maintained. There would also be a negative reaction to it in the market, people wouldn't want to buy the car but for their kids perhaps. It would be trivial to tamper with the device to disable it, which means it doesn't change the amount of traffic enforcement necessary. It also isn't illegal to drive at a high rate of speed on private property or private events."], "text_urls": [[], [], [], []], "score": [30, 9, 4, 3]}}, {"q_id": "6e6ud9", "category": "Repost", "title": "Why does an orchestra need a chief to perform? What is the man with a stick doing?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["di80k56"], "text": ["The conductor (person with the stick) sets the pace for all the different areas of instruments, to keep the whole group playing at the same tempo/timing. He or she also directs each instrument section in how loud or quietly they should play their part. The conductor of an orchestra is similar to the director for a movie in that they have an idea in their head of how everything should go, and then they coordinate everyone in how to play their part so that it fits together seamlessly."], "text_urls": [[]], "score": [6]}}, {"q_id": "6e78d0", "category": "Repost", "title": "How does a bar of soap reduce germs, when germs are rubbed directly on it?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["di83f2z"], "text": ["Because soap bonds with both fats and water. Normally you can't just rinse off fats and oils since they are hydrophobic - they don't like water and won't stick to it or dissolve in it. So you just get water running over your oily skin, and all the bacteria living in the oil or just under the oil remain. Soap, however, has molecules with an interesting property. One side of the molecule bonds with oils and fats, but the other side is hydrophilic - it really *likes* water and tries to stick to water when it can. So if you lather up with soap, the soap will bond with the oils and the vigorous rubbing will dislodge the oils and soaps while the water pulls them away, leaving your skin free of most germs and other gunk! The germs that end up on the soap itself get washed away due to the water, or die after a time anyway since soap is not particularly well-suited for bacterial growth, at least compared to oily human skin."], "text_urls": [[]], "score": [12]}}, {"q_id": "6e8ncs", "category": "Repost", "title": "What is happening when you \"defrag\" your computer?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["di8fuw5", "di8f9fm"], "text": ["Imagine a hard drive as a bookshelf. It starts out empty, but you quickly start shelving books (files) onto it. Some of these books are thick, some are thin. Every now and then you remove some of the books from the shelf (delete files). This leaves gaps between the remaining books. Afterwards, when you put a book on the shelf, the computer will try to fill one of those gaps. If the book is bigger than the gap available, the computer will cut it into two pieces: the first piece will fill the gap, and whatever is left will get stacked elsewhere. This file/book is now \"fragmented\". Now, if you ever try to go read that book, you will have to jump back and forth between the two pieces. Since this means that the hard drive has to physically move back and forth to read one file, this slows down reading the file slightly. After years of using a hard drive, and saving/deleting lots of files, many files become fragmented. This can slow your computer down significantly. De-fragmenting (\"defragging\") your hard drive is re-organizing your files, re-shelving the books, so that as many as possible are in one unified location rather than split apart.", "A hard disk has a platter (or several) and a read/write head that gets positioned over the right place. If you were to open one up (but don't, hard disks need absolute cleanliness and opening it will kill it quickly), [it would look like this]( URL_0 ) It takes a lot of time to move the head from one place to another. So when information is spread among multiple places on the platter, most of the time is going on movement rather than anything useful. Defragmentation is just moving stuff around so that the head needs to move less. This doesn't apply to SSDs, and defragmentation is not only unnecessary, but harmful to them. **Edit:** [A more technical video]( URL_1 ) on how it works **Edit 2:** To illustrate the difference defragmentation can make, let's suppose an example hard disk that reads at 100MB/s, and has 5ms seek latency. This means that if you want to read 100MB and it's all stored together on a hard disk it'll take a second, and that every time the disk needs to move the head, it'll spend 5ms doing so. Modern hard disks have 4096 byte sectors. Supposing the absolute worst case of the file being so fragmented that the disk needs to seek for every of the 25600 sectors in a 100MB file, it would take 128 seconds to read. Meaning fragmentation made things 128 times slower. In a more realistic case it wouldn't be that bad of course. But you can see how being fragmented into 100 x 1MB sized chunks would already add half a second to the time needed to read the file, causing a slowdown of 50%."], "text_urls": [[], ["https://www.youtube.com/watch?v=9eMWG3fwiEU#t=27s", "https://www.youtube.com/watch?v=kdmLvl1n82U"]], "score": [11, 3]}}, {"q_id": "6eak58", "category": "Repost", "title": "Are viruses living things?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["di8v2aj"], "text": ["Depends on what you mean by \"living things.\" Viruses make us realize that while we all sort of agree there's something called \"life,\" we're not totally agreed on the definition. Viruses have genetic material which is affected by natural selection, and multiply. Unlike us, they don't have cells, can't multiply without host cells, and don't break down other compounds."], "text_urls": [[]], "score": [3]}}, {"q_id": "6ebwlf", "category": "Repost", "title": "Why do we often sweat when sleeping even though the body is shut down and we wouldn't sweat if we didn't sleep?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["di961p6"], "text": ["What makes you think the body is shut down? Your body does all kinds of stuff while you sleep. Repair, cleanup, mental processing, basically biological maintenance."], "text_urls": [[]], "score": [6]}}, {"q_id": "6edkc3", "category": "Repost", "title": "Why do version numbers not increase by integer, but in an x.y.x format?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["di9hzic", "di9hngt"], "text": ["There's no single system for software versioning that's universally accepted. You're asking about one particular method that goes by the name of [Semantic Versioning]( URL_0 ) that breaks things up into *major*.*minor*.*patch* where incrementing a major version number is a sign that you've made a **major** change to the code like adding massive new features or rewriting large portions of the code. A minor version bump suggests that you've made less significant improvements & bug fixes while a patch version number increment tells you that *only* minor bugs were fixed. This is just one way to do it. Let's take a database system, like MySQL, that's used by big companies. You're on 5.5.12 and you make a **major** change to the software, giving you a 6.0.0 release. Since this is *very important* software, companies are still going to keep running the 5.5 branch until 6.x is stable and has all the bugs worked out of it. This means that you might get a 5.5.13 or even a 5.6.0 released **after** your 6.0.0 release. Simply going from version N to N+1 doesn't account for this. Another versioning system is the one the Linux kernel used. If you saw a 2.*even*.x you knew that was supposed to be a stable release intended for production use while 2.*odd*.x was meant for developers to work on the upcoming features for the next stable release (2.*even+2*.0) Then you get release numbers that are pretty simple & always increasing like Linux distributions. Fedora Linux, for example, just calls every major release \"X\" to be followed by \"X+1\" in a few months on a pretty fixed schedule, regardless of how much actually changes. If they make an update to X, you might see an updated X.1 if they build a new release out of it. Similarly, Ubuntu Linux releases ever April and October with *Year.04* and *Year.10* (eg - the last release was 17.04) and periodically updates those releases to with another minor point release (eg - 17.04.1)", "This varies from company to company, with many different policies. For example, they could say version 1.x.0 introduces a big new feature, and the 1.x.x fix problems that arise from that big new feature. Often there are internal versions that never see the light of day. For example, a company's software division might send off 1.1.0 to their testers, but that doesn't work, so they make 1.1.1, repeat , until they get 1.1.8, and that's the one they finally release to the public. Once they release that one, they start working on 1.2.0, this time they get it right in two tries so they release 1.2.2, and now do 1.3.0. Or it could be they base it on time, 1.14.1 would be the 2nd patch they made on the 14th month of development, 1.14.2 is the 3rd patch they made in the 14th month of development."], "text_urls": [["http://semver.org/"], []], "score": [7, 4]}}, {"q_id": "6eeaiy", "category": "Repost", "title": "Why did the Soviet Union collapse ?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["di9lqhf"], "text": ["> Perform a keyword search, you may find good explanations in past threads. Here are the first five results from the first page: URL_2 URL_0 URL_3 URL_4 URL_1"], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/ttipl/eli5_the_collapse_of_the_soviet_union/", "https://www.reddit.com/r/explainlikeimfive/comments/3io38v/eli5_the_collapse_of_the_soviet_union/", "https://www.reddit.com/r/explainlikeimfive/comments/j8sj7/li5_explain_to_me_the_collapse_of_the_soviet_union/", "https://www.reddit.com/r/explainlikeimfive/comments/580sdh/eli5what_caused_the_soviet_union_to_collapse/", "https://www.reddit.com/r/explainlikeimfive/comments/4soodd/eli5_the_collapse_of_the_soviet_union/"]], "score": [5]}}, {"q_id": "6efhpj", "category": "Repost", "title": "How have we decided on the colors and sounds of dinosaurs?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["di9vb71"], "text": ["While some hints can be inferred from structures, like sound from hollows present in bones, and colors from rare preserved delicate tissues, a lot of it is simply entertainment or artistic license. Movies want dinosaurs that look cool and sound neat. If dinosaurs actually looked like lumpy 1970s special effects and mewled like kittens, they don't care, because their intent is to draw in and captivate an audience, not provide a meticulous realistic depiction. Likewise, even illustrations for more scholarly works can only infer so much from the evidence that exists at present. That's why now you see new illustrations with some dinosaurs covered in thick feathers as opposed to scales, when this didn't exist before. It's an assumption based on new evidence, but still, to some degree, a guess, as we don't luck out and find many complete dinosaur skins lying about sadly."], "text_urls": [[]], "score": [5]}}, {"q_id": "6eh7qb", "category": "Repost", "title": "Why does porn seem not appealing, and sometimes down right disgusting after you've already finished? [NSFW]", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["diaa7ka"], "text": ["Disgust is how you brain gets you to avoid disease. Blood, faeces, decomposing things and other bodily fluids can be dangerous and carry diseases, so being disgusted by them makes an individual more likely to survive. Sex is required for reproduction, and sex involves disgusting bodily fluids. So in order to allow humans to reproduce, the brain disables disgust before sex. This allows you to fulfil your sexual urges without being repulsed by the fluids involved. After sex, all is done, you don't need to have sex again for a while, so your brain re-enables the ability to be disgusted, and you feel bad. Porn becomes disgusting after you finish, because it was disgusting the whole time, your brain just ignored that fact during the act."], "text_urls": [[]], "score": [9]}}, {"q_id": "6ehylq", "category": "Repost", "title": "How were the values of constants like \"pi\" found?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["diahkqi"], "text": ["I will try to do this explanation in a fashion that somewhat follows the historical development of \u03c0 (pi) computation, since that's the constant you mentioned specifically. Other constants would need explanations on their own. Because \u03c0 is a Greek letter, I will use its symbol instead of spelling it in ordinary Latin script. Since the question is about \u03c0, it seems natural to sometimes use letters instead of numbers; I hope a little (as little as I can make myself use) algebra will be okay. Before I do anything else, let's define \u03c0, so that we all know what we are talking about. **Definition:** \u03c0 is the quotient between the circumference of a circle and the diameter of the same circle. In other words, if you have a circle with circumference *C* and diameter *d*, \u03c0 is defined by \u03c0=*C*/*d*. The definition makes sense since if you double the diameter of a circle, you also double the circumference. The similar statement holds if you resize the circle by any factor. (This is a property of how distances behave when you resize shapes, and is nothing that's special about circles.) **Experimental calculation of \u03c0** == An excellent method to at least get an estimated value of \u03c0 is experimentally. Just draw a circle, and measure both its circumference and diameter! Measuring the diameter is easy to do very precisely, but measuring the circumference is actually fairly difficult. One way would be to lay a piece of string down along the edge of the circle, and to then straighten the string out and measure it. You can probably see why this isn't very precise. But anyway, experimental measurements can be done, and historically, this was the first way to determine \u03c0. I remember doing the string experiment in school when \u03c0 was introduced, and the answers of the class ranged between about 2.8 and 3.4. Obviously we were only children, but if you try for yourself, you will see that you do not get the same results consistently. Babylonian documents with \u03c0 estimated to be approximately 3.125 have been found. **Archimedes' calculation of \u03c0** == If you think about it, measuring \u03c0 experimentally does not really provide you with any exact knowledge. How can you actually know for sure that you drew your circle precisely enough? And how do you determine the precision of your measurements? The Greek mathematician Archimedes devised a solution to this problem. To begin with, we can draw one square around and one square inside our circle, like [this]( URL_5 ). If the circle has diameter 1, the outer square will have circumference 4, and the inner square will have circumference 2\u221a2 \u2248 2.8. (The side of the inner square will be 1/\u221a2 by the Pythagorean theorem.) Now, the inner square has smaller circumference than the circle, and the outer square has larger circumference than the circle, and therefore, we have arrived at the result 2\u221a2 < \u03c0 < 4. Therefore we have both an upper and a lower bound on \u03c0. Of course, our bounds are not very precise, but we need not limit ourselves to squares. We can continue with for example [octagons]( URL_7 \"The outer octagon is called circumscribed, and the inner is called inscribed.\") or other polygons with more sides. In this way, using 96-gons, Archimedes arrived at 223/71 < \u03c0 < 22/7, or 3.1408... < \u03c0 < 3.1428.... In the late sixteenth century, the Dutch mathematician Ludolph van Ceulen used almost this same method to calculate \u03c0 to 35 digits, which is enough for almost anything you can imagine. **Calculation of \u03c0 after the invention of calculus** == Modern methods of \u03c0-calculation come from calculus, a field of mathematics invented by Leibniz and Newton in the seventeenth century. By their very nature, these methods are difficult to motivate without using much more difficult mathematics than I have done so far. And since the formulas for \u03c0 will become more difficult at this point, I will unfortunately have to resort to modern mathematical notation. So from this point on, both the arguments and the formulas will be more difficult to understand. However, since 35 digits of \u03c0 were once obtained using the simpler methods above, you can consider this section to just be a bonus. In any case, one of these methods is [Leibniz' series for ]( URL_11 ) (\"series\" is math-speak for sum of infinitely many terms), which states that \u03c0/4 = 1 - 1/3 + 1/5 - 1/7 + .... A proof of Leibniz' formula for \u03c0 is found [here]( URL_3 ). The proof uses calculus, and trying to explain the proof to someone without using a lot of calculus would be a task for a better teacher than me, unfortunately. Observe that Leibniz' series is compactly written [like this]( URL_1 ). This probably looks very confusing, but perhaps [this example]( URL_14 ) will explain how the summation notation works, at least in the case of finite sums. (The big \u2211 is the Greek version of the letter s, and stands for sum. *i*=3 below \u2211 signifies that the sum starts with *i*=3, and the 6 above \u2211 signifies that the sum ends with *i*=6. The expression after \u2211, in this case *i*^2, is the expression for generating the terms of the sum.) A much better formula for calculating \u03c0 is [this one]( URL_12 ), due to John Machin (around year 1700). The function \"arctan\" used can be computed [like this]( URL_0 ). Combining these, we get [this expression]( URL_4 ) (without any fancy mathematical symbols) for \u03c0. John Machin computed the first 100 digits of \u03c0 using this formula. **Modern \u03c0 computation** == Finally, I'll mention something about the algorithms that are used for new records today. The current \u03c0 calculation records were set using using Alexander Yee's [y-cruncher]( URL_6 ). It uses two algorithms: The [Chudnovsky algorithm]( URL_13 ) ([Wikipedia page]( URL_10 )) and [one of Ramanujan's formulae]( URL_2 ) ([Wikipedia page]( URL_8 )). The Chudnovsky algorithm is used for the actual computation, and then the Ramanujan algorithm is used to verify the computation. There's almost no explaining why these contemporary algorithms work. Ramanujan originally published them in 1914 without proof, and nobody paid much attention to them until 1985 when Bill Gosper used one of them to compute \u03c0 to 17,526,200 digits. This meant that suddenly the mathematical community needed a proof for this formula (to be certain that Gosper's computations were valid). It took over a year for one to be produced. The history and some of the mathematics behind this formula are presented in [this paper]( URL_9 )."], "text_urls": [["http://upload.wikimedia.org/math/a/c/8/ac88e3ffdfbbac530b136f83211a87f7.png", "http://upload.wikimedia.org/math/4/b/3/4b325f4142cab62b1786d8be1ac3be60.png", "https://upload.wikimedia.org/math/3/c/c/3cca05380343cb6f78d776d5e40b3a9d.png", "http://en.wikipedia.org/wiki/Leibniz_formula_for_pi#Proof", "http://i.imgur.com/S2kxbEc.png", "http://www.mathteacherctk.com/blog/wp-content/uploads/2010/06/SquareCircleSquare.jpg", "http://www.numberworld.org/y-cruncher/", "http://personal.bgsu.edu/~carother/pi/pigifs/inc-circ-8gonx.gif", "https://en.wikipedia.org/wiki/Ramanujan%E2%80%93Sato_series", "http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.158.2533&amp;rep=rep1&amp;type=pdf", "https://en.wikipedia.org/wiki/Chudnovsky_algorithm", "http://upload.wikimedia.org/math/9/e/8/9e804b8a1a11e442be93fed1d52205a9.png", "http://upload.wikimedia.org/math/f/1/5/f15dc3d39c473c4bd718e3a98145da0d.png", "https://upload.wikimedia.org/math/9/7/e/97e0706f5d97298fd0f75e2b3022b776.png", "http://upload.wikimedia.org/math/1/a/6/1a693bfe9a392b08ed135a9e4117d3b9.png"]], "score": [3]}}, {"q_id": "6ei39i", "category": "Repost", "title": "Why does your body temperature rise when you have a fever ?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["diagdgk"], "text": ["The ultimate \"why\" is to provide a less favorable environment for bacteria to grow and divide. It's actually a surprisingly old evolutionary trick, as even some cold-blooded animals like iguanas will seek out heat when they get sick. The practical \"why\" involves an area in the brain called the hypothalamus. It has a sort of thermostat for the body, which can be turned up during infection. This is important for maintaining fever. Normally if you get hot, you feel uncomfortable and try to cool down. In fever, you're hotter than normal yet *feel* uncomfortably cold, and will do your best to stay as warm as possible."], "text_urls": [[]], "score": [3]}}, {"q_id": "6ei5wc", "category": "Repost", "title": "Why do regular citizens vote for the president, even though our vote doesn't elect the president?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["diahc9j"], "text": ["The president isn't elected in a direct popular vote, but the popular vote in each state determines how many electoral votes each candidate gets. Originally this was designed so that the states would decide the president, but the states all decided to allocate their electors by popular vote. It's been that way since the 1830s."], "text_urls": [[]], "score": [4]}}, {"q_id": "6ej6vp", "category": "Repost", "title": "If race is a social construct, why do most Asians have epicanthal folds in their eyelids? Why are there more blondes in Scandinavian countries than in Africa?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["diaos4r", "diapjtz"], "text": ["Do those differences mean that the people have different capacities, or should be treated differently to any other peoples? The bit where we do that is the social construct.", "The way people look changes continuously over generations, and populations blend into each other, forming new groups over time through the merging and division of past ones. What physical features people in any given time period choose to focus on is arbitrary. For instance, someone with red hair and very pale skin (a \"ginger\") would have been singled out as a race in Roman times - a feature of the Celtic gene pool. Their appearance distinguished them and led to discrimination for a long time. Likewise, blondes with blue eyes were considered a \"barbarian\" race, stereotyped as stupid, violent, drunken illiterates because they came from tribal lands North of Roman influence. Ginger and blonde are not considered races now, just subtypes of \"white\" people - a broader race that has come into social focus in modern centuries due to the extreme disparity in wealth and technology that Europe attained through the Industrial Revolution. Similarly, before large-scale contact with people outside of their broad genetic grouping, there was no internal group identity of \"black\" people in Africa, nor of \"Oriental\" people in Asia. These groupings result from contact with people who had greater differences than the nearer groupings - i.e., a *social construct* based on relative differences. Among very isolated peoples, the distinction between one \"race\" and another might be from one valley to another - slightly lighter hair, slightly taller stature, a slightly different shape of nose. People invent distinctions to fit their circumstances. The idea that Chinese, Japanese, Vietnamese, etc. people would belong to a single \"race\" group would have been found ludicrous to all of them at most points in their history, and in fact at most points even those modern groups would have been considered extreme generalizations of the local subgroups that now comprise them. Those groups formed out of the fusion of many. In the future, the \"races\" defined in the present will probably lose focus and new ones will be defined by future demographics. This will be especially true when and if future political changes or catastrophes drive various groups of people together, creating both melding and politically-driven resistance."], "text_urls": [[], []], "score": [3, 3]}}, {"q_id": "6ejzef", "category": "Repost", "title": "What causes the need for routers and modems to be reset every so often and why can't they design them to not have to be reset?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["diavpvz"], "text": ["Think of your router as a computer just like any other PC. It has an operating system, usually linux in home routers, but possibly Cisco IOS in a enterprise class device. Like any other OS it has file storage, working memory, and services it runs. If the operating system isn't configured correctly for high uptime with periodic cronjobs to check for hung processes to restart them, it is possible over time for a service to hang or run out of memory much like a windows program that doesn't want to close. If you had SSH access to the routers command line you could simply restart the affected service rather than rebooting or power cycling. There is a lot of maintenance work involved in keeping a computer in service for long periods. Temp files must be cleaned, high memory usage must be monitored and processes triggered to restart to work around memory leaks. Log files must be tar'd up and old logs deleted to prevent it's file system from becoming full. With many routers for home use you get what you get and you're not able to change these things. Some of the better routers, and routers that run open source firmware often allow the user to schedule maintenance actions like periodically restart critical processes a few times a month, or keeping the file system tidied up. Some common failures are below 1. DHCP service hangs or stops responding. Previously connected devices work fine but newly added devices, or roaming devices like cellphones lose network connection when they renew their IP address. Since DHCP doesn't advertise, they default to a self assigned IP like 169.x.x.x which is not in the normal IP range so they go off network. 2. The apache or tomcat service which serves the GUI and webpage runs out of memory and stops responding. Network connections may work but if you try to log into the router it times out or disconnects. 3. A critical service like DNS or the routing tables become corrupted or stop responding causing network level failures. 4. The cable modem actually has the problem and when it is corrected the router doesn't re-establish connection. Rebooting it causes the cable modem to assign a new IP to the router and re-establishes the internet connection."], "text_urls": [[]], "score": [5]}}, {"q_id": "6ejzml", "category": "Repost", "title": "why is hockey the only sport where fighting is socially acceptable/minimal penalty is given for fighting. Was this always the case?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["diaw0zr"], "text": ["Hockey is a sport that is really built into people getting physical with each other. Lots of swinging weapons and sliding into each other is a natural part of the game, so people get physical a lot which goes from accidental slamming to intentional checking to just punching each other pretty easy. The penalties are low because the sport started pretty unregulated and no one cared so when the game got bigger it was already just a part of the game and it rarely leads to real injury and people love it so no one wants to get rid of it that bad."], "text_urls": [[]], "score": [3]}}, {"q_id": "6f1309", "category": "Repost", "title": "What would happen to light inside of a box with a mirror-wall interior?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["diekm94"], "text": ["Assuming that the hypothetical box is completely and perfectly enclosed with no way for the light to escape, the light would infinitely reflect within the box while gradually losing energy until it dissipates. Meanwhile the box will become warm (hot, maybe?) because the light energy is converted into heat energy every time the photons impact and reflect off of the mirrored interior of the box until they eventually lose all their energy and disappear."], "text_urls": [[]], "score": [5]}}, {"q_id": "6f1aa4", "category": "Repost", "title": "What is the difference between Britain and England, and what is the country currently called?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["diemecf", "diemu6p", "diemxjg", "diemjqi"], "text": ["The United Kingdom (UK) - A sovereign state made up of parts of two islands (the British Isles) England, Scotland, Wales, Northern Ireland - The 4 nations that make up the United Kingdom Great Britain - The larger of the two British Isles. Contains England, Scotland and Wales Ireland - The smaller of the two British Isles. Contains Northern Ireland and the Republic of Ireland", "URL_0 The Difference Between The United Kingdom, Great Britain, England And A Whole Lot More", "Britain is one of the names of the Empire based on the British Isles. It is officially The United Kingdom (short name). England is one of the kingdoms that is a part of the UK. It is the nation that holds Parliament and where the Queen lives. The other kingdoms of the UK are Scotland, Wales, and Northern Ireland, and there are numerous holdings around the world that are Crown Dependencies and overseas territories. There are also entire modern nations that are subjects to the Queen and therefore subjects of her empire but who are not a part of the UK (Canada, Australia, New Zealand). So things can be complex.", "Deleted and reposting because I can do it better. The current country is called \"the United Kingdom of Great Britain and Northern Ireland\". Some people call it the UK for short, some people call it Britain for short, which is fine but not technically correct. There are four countries that unite to form the UK. Each one used to be independent (or part of another country) before they united. Those four countries are England, Scotland, Wales, and Northern Ireland. The geographic island which is made up out of the lands of England, Scotland, and Wales is called \"Great Britain\" or Britain for short. Northern Ireland is not on that island. It's on another island to the west of it called Ireland. Most of Ireland is its own independent country (the Republic of Ireland) but one bit is still part of the UK and that bit is called Northern Ireland."], "text_urls": [[], ["https://youtu.be/rNu8XDBSn10"], [], []], "score": [11, 3, 3, 3]}}, {"q_id": "6f1ffq", "category": "Repost", "title": "Why did Nixon resign?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dien2ri", "dienefw", "dieo5gz"], "text": ["Nixon resigned because the House was about to vote to impeach him for obstructing justice in the Watergate investigation. Nixon had his key advisers hire some guys to break into the opposing political party's headquarters and steal their things and then tried to cover it up. Because his role in the cover-up was being exposed, he resigned to avoid being removed from office.", "Nixon was about to be impeached (put on trial for misconduct) for obstructing justice in the Watergate investigation and for illegal wiretapping. There was more than enough evidence for this impeachment to result in him being removed from office by force. Resigning before the impeachment was his way of saving some small fraction of honor for himself and the country and simply saved a long drawn out impeachment process of being done. He was open to face criminal charges for his actions either way but by stepping down before impeachment he was also put in a place where his successor could pardon any possible crimes that he had committed. Impeachment is one of the few things that the President does not have the authority to pardon and while it has not been legally tested it is fair to assume that criminal charges filed as a result of impeachment would equally be immune to being pardoned. So it is possible that by resigning he was 1) Removing the need and option of the Supreme Court ruling on if crimes discovered in the trial process of impeachment are immune to pardons. 2) Was a deal with his successor to get a pardon, which he did.", "To avoid the impending impeachment proceedings against him. The Nixon administration employed numerous shady and oft outright illegal methods to help secure his re-election, including but not limited to harassment of activist groups that supported opponents using the FBI, CIA and IRS; bugging and wiretapping political opponents, and having some underlings break into the Democratic headquarters at the Watergate complex, which is where the scandal comes from. Thing is, that last bunch got caught and arrested. The press was originally told that these were Cuban Freedom Fighters (the early 70s equivalent of \"it's terrorists\"). These were very different days, however, and the government actually began to investigate, despite orders to the contrary from the top. The money got followed, and it quickly was unearthed that large cashier's checks (25k; that's about 150 000 each in today's values) from the Nixon Re-Election campaign were given to ex CIA and FBI men loyal to the party; notably one of the burglars arrested... As the money continued to be followed it wormed its way to the top; these had been cleared through the Republican party and the CRP, and meanwhile the white-house \"inexplicably\" was moving to distance itself from these men it was \"completely unrelated\" to. Luckily however, Nixon had a tendency to tape *everything* in his office all the time.... Of course just before those were leaked (today that would be 'treason') congress - which had a spine at the time - was in full hearings on the subject, with Special Prosecutor Archibald Cox immediately subpoenaing the tapes. Nixon claimed executive privilege and ordered Cox to drop the investigation. Cox refused of course. This led to the \"saturday night massacre\": Nixon ordered the Attorney General to fire Cox. The AG refused to perform such a dirty act and resigned, thus Nixon passed on the order to the next in line, the Deputy AG, who also resigned in refusal. This continued all the way to the Solicitor General, who agreed and fired Cox. This was the moment when, questioned about it, Nixon made his famous line; \"I am not a crook\". At this point Nixon was secretly indicted as a co-conspirator to the seven men who had helped act in the crimes and coverup (out of a total of 48 found guilty by the end of things) to a Grand Jury. Nixon released small portions of his transcripts as per the subpoenas, with \"profanity\" and \"anything that could be related to national security\" edited out. Again, not as bad as entire documents blacked out as done today, but while it originally gave him a good image to do so, reading the documents left people feeling quite 'unclean'. Then the tapes were brought out, with conversations about how to cover things up right there in the open, except for certain long portions of what was likely far more incriminating stuff \"accidentally\" deleted here and there. \"accidentally\" of course. With the final investigations closing in and impeachment proceedings on the verge of officially commencing, Nixon resigned officially."], "text_urls": [[], [], []], "score": [4, 4, 3]}}, {"q_id": "6f2vrp", "category": "Repost", "title": "What would happen if you wake someone up if they're sleepwalking? Can it harm them or is it a myth?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dieyrej"], "text": ["I think the bigger danger is that they could harm you. Someone who is sleepwalking is not consciously controlling their actions, and depending on what they are dreaming about they may interpret an attempt by you to wake them up as an attack and respond in kind. I suppose they could also injure themselves in a similar manner, bit that seems less likely to me."], "text_urls": [[]], "score": [3]}}, {"q_id": "6f4e63", "category": "Repost", "title": "How do we know how far certain stars are from us even though they are far beyond our reach?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["difbpts"], "text": ["One method for nearby stars is called \"parallax\", and it's basically just how it moves relative to other stars while Earth is moving around the Sun. This gives rise to a unit of distance you may have heard - the parsec. This is the distance corresponding to a parallax angle of 1 arcsecond (1/3600th of a degree) per year, and is a bit over 3 light years long. For farther stars, a different method is used based on what kind of light comes from certain types of ordinary stars and supernovas called \"standard candles.\" Since we know how these stars work, we know what kind of light to expect from them, and can thus use what we actually receive as an indication of how far away they are based on how dim the light is. This latter method is statistical rather than exact, because there are a number of complicating factors, but astronomers can establish upper and lower limits on the distance using that and other factors (e.g., comparing to other stars around it that have likewise been calculated). The short answer is that for most stars, we *don't* know how far they are for certain, we just have reasonable theories."], "text_urls": [[]], "score": [3]}}, {"q_id": "6f58ay", "category": "Repost", "title": "How does Walmart know what I've bought in store?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["difisex"], "text": ["If she used a credit card or a debit card your name is on those accounts and they know who you are. So if she bought with cash this is creepy, but all other payment methods has a link to her account in some manner."], "text_urls": [[]], "score": [3]}}, {"q_id": "6f654c", "category": "Repost", "title": "why do humans brush their teeth even tho no other animal does it.", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["difq4wg", "difw6yv", "dig20dh", "dify2sn", "diftk22", "difszug", "digopys"], "text": ["We're one of the few animals to eat a high-carbohydrate diet, a diet only possible because we grow grains as crops with agriculture. Because we eat carbs, we leave lots of delicious bits of sugar behind on our teeth for bacteria to feast on, causing tooth decay. If we don't brush, we can get painful cavities and our teeth can fall out. This is a huge health problem, and was even worse before modern oral hygiene practices. Domestic dogs that eat corn-based dog food also need to have their teeth cleaned, which wild dogs don't need. Luckily there's chewy dog treats you can give your dog that do a decent job at cleaning their teeth so you don't have to do the unpleasant task of literally brushing your dog's teeth with a toothbrush.", "Our diet is rich in sugars, which bacteria love, because most our foods contain complex carbohydrates: think wheat, potatoes, fruit. Our food simply leaves a buffet for bacteria to feast on behind in our mouths. Second: we learn. We've discovered that certain foods do this more than others, and we've learned that fluoride helps counter this effect. That means brushing alone is already neat (the calcium (chalk!) in the paste scrapes away most of that buffet), and that brushing with fluoride actually counters most of the effects! How we've discovered fluoride does this: we observed that over the span of decades, some towns' people suffered tooth decay less than others, and we looked and found that their water supplies contained more fluoride. Off to the lab to check if fluoride indeed does this, and yup: it does. Voil\u00e0, fluoride based toothpaste became a thing. Add SLS to make it bubbly through friction, so that the bubbles can get the fluoride more between your teeth; add mint to make it nice and fresh; and bam: modern toothpaste for you.", "While a high-sugar diet that everyone else talked about is the main reason, we're also the only animals to shave, wipe our butts, wash our hair and use deodorant. It's kind of just another part of hygiene in human society to have clean teeth and breath that doesn't stink.", "Lots of answers, but mainly: because we can. Other animals have terrible teeth and terrible breath. We like to take care of ours, because we live a long time and need them.", "Other animals don't brush their teeth but there are several that have other animals clean their teeth. Sharks have little fish, crocodiles, hippos have small birds and there's probably other teeth cleaning relationships.", "I have a number of dogs. Those that chew sticks have clean teeth while this that don't need dental care at the vet. I'm thinking that stick chewing is an evolutionary adaptation to maintain oral health.", "Human diet is normally rich in sugar, and animals and even the people of Pompeii before the eruption have been found to have good teeth and no cavities. And correct me if I'm wrong, but i believe the people of Pompeii used honey to sweeten their food instead of sugar. But then, sugar isnt the only thing that effects teeth, sodas, do aswell. So i believe its carbohydrates that effect teeth and there wasnt much of that for probably, 90-95% of recorded history."], "text_urls": [[], [], [], [], [], [], []], "score": [235, 21, 6, 5, 5, 4, 3]}}, {"q_id": "6f9u0a", "category": "Repost", "title": "Why is it when on a slow internet connection ads on youtube do not have to buffer at all and play in high definition, but when the video starts, it has to buffer even on the lowest quality setting?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["digkmj3"], "text": ["YouTube videos end up fitting into two categories: a small number of videos that get watched A LOT, and a large number of videos that only get watched sometimes. Videos in the second category are stored on YouTube's big ol' server setup, but videos in the first (the popular ones) are cached on boxes at ISPs around the planet. This makes retrieving those videos MUCH quicker. Know what's also on those boxes? The ads! Because ads are also almost always regional (specific to your country and language). So if you watch a youtube clip that came from the big archive, it's able to pull an ad immediately from the local cache then has to do more work to get the one that's stored on the big archive."], "text_urls": [[]], "score": [3]}}, {"q_id": "6faxes", "category": "Repost", "title": "Why are some penises curved while others are straight and does any external factor, like underwear, affect it?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["digu06q"], "text": ["From a previous post: There are 2 'tubes' that fill up with blood when it become erect. If one of them is shorter then the other that can cause it to be curved. Edit: Just to let everyone know. I'm not a doctor or anything. I just knew that fact from some weird youtue loop I got stuck in watching British Sex Education shows."], "text_urls": [[]], "score": [3]}}, {"q_id": "6fb9d6", "category": "Repost", "title": "why do babies have a distinct baby smell? What causes it?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["digv0vd"], "text": ["You're probably referring to baby powder. It's not natural, you have to apply it. But it's pretty widely used, and the kind without talcum still smells the same. A lot of other baby products - Johnson's baby wash, for example - has the same scent. Left to their own devices, babies smell like shit and vomit."], "text_urls": [[]], "score": [3]}}, {"q_id": "6fbndb", "category": "Repost", "title": "How do space stations and satellites manage to not collide with space junk?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["digz9so"], "text": ["Every single piece of stuff up there bigger than a screw is tracked, seriously! It really is. But space is BIG, truly unimaginably big. So we know where the stuff is flying around, so we just use all that other big empty space so that they don't collide"], "text_urls": [[]], "score": [3]}}, {"q_id": "6fh9s6", "category": "Repost", "title": "How is light a wave AND a particle?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dii53rf", "dii5i1h", "dii8jlt"], "text": ["It isn't really. Light is something that sometimes behaves in way that is best described as a wave and sometimes in a wave that is best described as a particle. Light is neither of both, it is ... *light*. We don't know exactly what it is apart from that. But we know that we can make quite accurate science with it when we treat it like a wave in those situations where it behaves like a wave and treat it like a particle in those cases when it behaves like a particle. For the record, everything in the universe is that way. Also electrons sometimes behave like waves. Even really big molecules sometimes behave like waves.", "Welcome to quantum mechanics! I believe the unfortunate answer to your question is: we don't know. But if you can explain it, proceed to GO and collect your $200 (or Nobel Prize). While we don't know HOW it is, we can demonstrate light having both properties via the [double-slit experiment]( URL_0 ).", "Unfortunely it sorta isn't. The full (very, very complex) answer comes from QED (quantum electrodynamics). Which (basically) says that \"excitations\" in a certain fields result in a certain phenomena. A 'photon' is essentially just an excitation in the (electromagnetic) field (this means radio, microwaves, visible light, electricity and magnetism, are -mostly- all the same thing). The idea that a field excitation is both a \"particle\" and \"wave\" comes from the weird way these fields work. The answer is --long. Sufficient to say, \"photon\" is just shorthand for a particular excitations. And \"light wave\" is another. But, really they're not categorical different enough to say they can \"be\" anything --and certainly not at the same time."], "text_urls": [[], ["https://en.wikipedia.org/wiki/Double-slit_experiment"], []], "score": [10, 5, 3]}}, {"q_id": "6fhq8s", "category": "Repost", "title": "Why do people believe they can feel when a storm is coming indicated by pain or discomfort from recent/old surgeries, injuries, etc.?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dii8yfg"], "text": ["Things like air pressure or humidity can affect injuries, past surgeries, ect. and cause pain, discomfort, or some other feeling. Changing in air pressure or humidity tend to signal changes in weather."], "text_urls": [[]], "score": [5]}}, {"q_id": "6fjo8q", "category": "Repost", "title": "Why are most radio stations in the 90, 90.5, 91.5, etc", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["diipcij"], "text": ["because the fm spectrum is 87.8 MHz to 108.0 MHz, for a total of 20.2 MHz. It is divided into 101 channels, each 0.2 MHz wide. so a radio station thats 90.5 is actually 90.4 to 90.6, so just tune to the center at 90.5 for the best signal."], "text_urls": [[]], "score": [3]}}, {"q_id": "6fjuep", "category": "Repost", "title": "what is the point of keeping the penny around if it costs more than a penny to produce it?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["diiqn8n"], "text": ["There is not a point to keeping it around (in my opinion), but it really depends on the person. I highly reccomend [CGP grey]( URL_0 ) He makes some REALLY great videos on why we should remove the penny from circulation, and just really interesting stuff in general (like the theory beyond completely stopping traffic jams)"], "text_urls": [["https://www.youtube.com/user/CGPGrey"]], "score": [3]}}, {"q_id": "6fl1ma", "category": "Repost", "title": "why movies generally shoot at 24 fps, but video games generally go for 60 or higher fps for the most cinematic experience?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["diiyfqm", "diiyvyw", "diiz1bs"], "text": ["Mainly because of motion blur. When your videogame creates the video, each frame is generated separately, and is a completely static image - you can take a screenshot and it will not appear as if it was a part of a video. When you shoot a movie, each image is exposed for a non-negligible amount of time, such as 1/60 or 1/100 of a second. During this time, motion is captured in the image, resulting in a small blur. This contributes to making the video appear more smooth. [This video]( URL_0 ) shows the difference between high shutter speed (= no motion blur) and low shutter speed (= motion blur).", "Movies are shot, games are rendered When an object is moving in a movie each frame will have blurring showing the direction of the motion. This is because the object is able to move across the film/sensor while the lens is open during each frame. This blurring is similar to what your eye would see while watching a moving object, and when shown at 24 fps it is close enough When an object is moving in a video game it is often rendered as a series of crisp images so you need them coming in faster to create the correct blurring effect in the eye. Without the blurring it acquires the odd effect that stop motion movies have where it looks kinda smooth but you *know* its not smooth", "24Hz is the lowest you can go before humans notice the flickering. So this is how you get the longest movie on the shortest film roll. If you see old films they might be lower frequency, as low as 10Hz at which point the flickering is very noticeable and tiring. But even at 24Hz you may notice the stuttering images even if they are not flickering. To fix this on digital images there is interlacing which allows you to double the frame rate without increasing the bandwidth. This is why things shot with a TV camera looks better on a TV then things shot with a film camera and then scanned to TV format. It is also popular for TVs to double the frame rate again by interpolating the intermediate frames. So for TV it is not unusual to have 100Hz. The movie industry is not as keen on jumping on to higher frame rates and rather value higher resolution. But you do get some 48Hz movie systems. For example the Hobbit was shot in 48 frames per second."], "text_urls": [["https://vimeo.com/11340117"], [], []], "score": [9, 3, 3]}}, {"q_id": "6fpu0n", "category": "Repost", "title": "Why does a tilt-shift lens make subjects look miniature?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dik9nqe", "dikfydz"], "text": ["Classic [view cameras]( URL_1 ) have the ability to not only move the lens in and out for focusing purposes, but to tilt and shift both the lens and the film plane. This gives you the ability to adjust for perspective distortion and have variable focus fields in ways that an ordinary camera could never come close to producing. As one example, an ordinary camera has a focus plane which means that there's a plane in space in front of and perpendicular to the the camera's line of sight where everything is in focus, and anything nearer or farther than that plane will be progressively out of focus. A view camera, on the other hand, lets you change that plane so it's no longer perpendicular to the line of sight. So imagine you're photographing a scene where there's something to the left and near you, and something to the right and far away. A view camera would allow you to put both of those objects into focus. There's a [gallery on flickr]( URL_2 ) that contains some beautiful tilt-shift images. ---- Now a view camera can also be used to create the opposite effect. You could use the tilt-shift features to create an extremely restricted range of focus. By coincidence, when you use a normal camera to photograph miniatures, the camera will also have an extremely limited range of focus. Photographs of miniatures very often have the foreground and background out of focus whereas a photograph of an actual landscape would have everything in focus. Our eyes and brains have seen enough photographs of miniatures that we've learned to associate the limited range of focus with looking at miniatures. So now, when we look at a landscape that was photographed with the above-mentioned tilt-shift effect, it makes us think we're looking at a photograph of a miniature. It also helps a lot to shoot the scene from above, as a miniature would be photographed. ---- Finally, we come to the computer \"tilt-shift\" effect. This is nothing more than drawing a line through the scene (typically parallel to the horizon) and having the computer blur the scene progressively away from that line. And if the scene is animated, you can do other things to make it look like a miniature, such as speeding up the time frame or making the animation a little jerky so it looks like it was generated with stop-motion animation. There's [a video]( URL_0 ) that demonstrates this wonderfully.", "You, whether you realize it or not, experience something called \"depth of field\" in your vision. When you are focused on something close up, things that are far away are blurry. When you focus on something far away, near-by things are blurry. Now there's a lot mechanics, purely optical mechanics, as to why and how this depth-of-field works. Explaining all of them would take several hours and a larger character count than I have here. But basically the amount of \"in focus stuff\" is a percentage of how far away from the lens (camera or eye) the thing being seen happens to be, and the narrower the opening around the lens' center, the higher the percentage. So pin-hole cameras can seen nearly 100 percent of the depth, and that's how you can get a cheap disposable camera that you don't have to focus at all. So anyway, if you look at something very close (or take it's picture), you'll notice that the things that are even closer or just a touch further away are blurry. But if you look at a distant tree you'll see that the whole forest is in focus. So go back to that percentage thing. Pulling numbers out of my arse, say I've got ten percent depth of field. If I look at something ten inches away I'll be able to clearly see the things ten inches away, and a half-inch closer than that, and a half inch further than that (because 1 inch is ten percent of ten inches.) but something one in closer or further away (e.g. at nine inches, or eleven inches) are outside that one-inch-thick \"10% depth of field\". If I look with the same optics ratios (lens opening width etc) at something ten miles away I get the same 10% depth of field so I get to see everything from 9.5 to 10.5 miles away as \"in focus\", but something \"only 9 miles away\" or something \"over eleven miles away\" will be blurry. The further out of the focal lenghth, the more blurry things are. So at 20% its really blurry and at 40% it's so out of focus that your brain just doesn't even bother with it unless you move your eye and re-focus. Now we add a feature. Our eyes constrict the opening around the lens when there is more light. The higher the light levels the smaller the opening. The smaller the opening the larger the depth of field. This is why, on a bright and sunny day, the whole world just feels sharper and more in focus. More of it _is_ factually in focus, you can literally see more of it well at each moment. As an added bonus you have binocular vision. You can tell how far something is from your face by how much your eyes have to cross to see it. If you'd never seen a picture of a landscape before you might be a little confused as your brain would say \"deep\" by being able to see it all at once, but your cross-eyed-ness would say \"close\". It's not a huge effect and you know about models, so it's easy to say \"photograph\". That is your brain knows about dolls and miniatures and stuff like that so it can cope with the \"confusion\". So back to tilt and shift... I show you a tilt-and-shift image of say a town. There's a guy in the center of an intersection. He's in focus, but the buildings right above and below him are not in focus. 1. Your brain knows from the binocular vision that the whole picture is close to you. 2. Your brain knows that the lights are good and your irises are constricted so it should have XXX depth of field, so lets say 20% just for example. So the blurry buildings must be at least 10% closer in the \"near\" part (lower building) and 10% further away in the \"far\" part (higher in the frame building). And if the next most blurry thing is really even more blurry it must be even further out of the depth of field. So your brain does some organic math. Using \"one guy\" (the thing that's in focus) as an estimating tool, it guesses \"how many guys\" it would take to get from the in-focus guy to the blurry buildings. In a normal picture of a guy far away, e.g. the picture before the tilt-and-shift effect was applied, the nearest blurry building might be a hundred or a thousand guys away from the guy. In the effected picture it's only eight or ten guy away (or whatever). So if you get to see a hundred or a thousand \"guy's worth of depth\" the guy is big and far away, for the same reason that one tree ten miles away lets you see from 9.5 to 10.5 miles clearly and that's a whole forest of trees. But if only get to see like six \"guy's worth of depth\" then the guy must be very close and very small like how looking at a model of a tree ten inches away only lets you clearly see from 9.5 inches to 10.5 inches. So the more narrow the in-focus area is the closer to your face and the smaller the objects \"must be\" for the percentages to work \"in the camera\", whether that camera is a real camera, a photoshop image, or your actual eyeball. Finally the other part of the tilt and shift (I don't remember which part is which, but I think this is the \"shift\" part) is that the line of what is \"in focus\" is usually shifted from the apparent horizon. So the in-focus band isn't square to the image. This gives a disassociated feeling, as the the thing being looked at is unreal, as in a model, being looked at from an angle. We live most of our lives \"square to our chess board\" when we are involved, when things are \"Real\". But when we look at a diorama we can look in-and-down at interesting angles and such. So by adding that angle to to the in-focus band the effects artist has given our brains permission to consider that the scene is in some way artificial. So that gives us permission to call the image \"fake\". In the end \"fake\", \"close\", and \"tiny\" signals are all provided very, strongly. So much so that \"real\" and \"full size\" are \"impossible\". So our brain \"knows\" it's a tiny, tiny model captured from very, very close up at a slightly cock-eyed angle."], "text_urls": [["https://vimeo.com/3156959", "https://en.wikipedia.org/wiki/View_camera", "https://www.flickr.com/groups/tiltshift/pool/"], []], "score": [18, 4]}}, {"q_id": "6fqab6", "category": "Repost", "title": "What is wind", "title_urls": {"url": []}, "selftext": "What cuases wind to happen?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dik5idd"], "text": ["One amount of air gets hotter than another. Hot air expands. This expanding hot air moves, causing wind. Evaporation of water moves heat from the surface to the air. This, and sunlight causes air to heat, causing wind. Edit: u/cedarbabe is right about it being about pressure, not hot air's expansion."], "text_urls": [[]], "score": [4]}}, {"q_id": "6fra16", "category": "Repost", "title": "Why is 'good night' a farewell phrase but all the other times of day (morning, afternoon, evening) are greetings?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dikfjbs"], "text": ["I had this explained to me during my second year of German class. In English we say \"good night\" to end the night like you said, with all other similar phrases being greetings. In German we have; \"Guten morgen.\" (good morning), \"Guten Tag.\" (good day), \"Gute Nachmittag.\" (good afternoon), \"Guten Abend.\" (good evening), and \"Gute Nacht.\" (good night). The last two are used around the same time. However using \"Abend\" is either a greeting if meeting around dusk and onward or a parting phrase if leaving in the evening. Using \"Nacht\" signifies you are going to sleep upon your departure or reciprocating someone's departing statement of \"Gute Nacht.\" In my opinion it is just a culture thing that has to do with how our language is set up. I don't know about any other languages though."], "text_urls": [[]], "score": [5]}}, {"q_id": "6fravo", "category": "Repost", "title": "Why does a video of a spinning object suddenly make it seem like the object stops spinning and then continues in the other direction? (i.e. A video of a cars wheels)", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dike6c4"], "text": ["Imagine a wheel has six spokes. That makes sixty degrees of rotation between spokes. Videos aren't actually motion, but sequential pictures that when strung together fast enough blend together to appear like motion. So let's say the wheel is moving one degree per frame. It will look like it's moving one degree per frame, because it is. If the wheel moves two degrees per frame, it will look like it's moving two degrees per frame. But there are sixty degrees from one spoke to the other, so if the wheel moves sixty degrees each frame then it will look identical to the previous frame, as if it hasn't moved at all. And if the wheel moves fifty-nine degrees in a frame, it will look like it's moving one degree backwards instead. This is because we don't see the motion. We just see two pictures and make the most logical connection from each picture to picture."], "text_urls": [[]], "score": [3]}}, {"q_id": "6ftint", "category": "Repost", "title": "Before proper dental hygiene how did people eat without constant pain in their teeth?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["diktcb1", "dila9cu", "dikuc0x", "dikyycv", "diktfc3"], "text": ["They didn't. Most diets before the industrial revolution were fairly free of sugars, so they had that going for them. But the complete lack of dental hygiene meant that their teeth could, and did, rot quickly. Places like Egypt actually show a lot of this -- many bodies show significant enamel erosion since much of their food was laced with sand (unavoidable) and this accelerated the decay of their teeth. Next time you're at your dentist, thank them for their work.", "Great question and I just wanted to share a story of how some current people without proper hygiene eat without pain... I work with a group that provides oral outreach to orphans and children in Malawi, Africa and South America. We go into some of the world's most remote villages and bring toothbrushes and toothpaste, along with dentists and hygienists who volunteer from the States. The majority of the people we visit have never owned oral hygiene products and line up for miles and miles just to get a travel-size toothbrush and toothpaste. During my first trip, I expected everyone's teeth to be decayed and rotted, but many, surprisingly, actually had great oral hygiene. This was most apparent in villages with sugar cane because the phytates attack the bacteria. They suck the juice out and then chew on the stalk and it's very effective. They also maintain decent oral hygiene because their diets are natural and not full of process foods and sugars, etc (the sugar cane is raw). With that being said, we certainly see many horrific cases and it breaks my heart because I can't imagine the pain and suffering some endure with mouth decay and rotted teeth. Some of their necks will swell the size of a grapefruit or larger! Malawi\u2019s HIV prevalence is one of the highest in the world, so many of their immune systems are already compromised and proper oral hygiene is paramount. On a positive note, one thing I always love is the kids get really excited to receive their first toothbrush! They'll hold and caress it like a prized, sacred possession and their eyes light up at the special gift. Seeing that fuels me every single time I get over there to serve. So to answer your question, they find natural ways to clean and protect their teeth and I'd imagine it's the same thing people did in the historic days. Edit: Tried to simplify", "They lived with dental problems. Our wisdom teeth is an interesting aspect of this. Back then, we would have certainly lost some teeth when our wisdom teeth began to set in. Today, we don't have room in our mouth to for them, so we have to remove them surgically.", "Read up about Dr. Weston Price he wrote about this kind of stuff. He was one of the first to find out that groups of people who ate a lot of grains and sugars had poor oral health compared to grouos of people who didnt. So while you had rich Europeans suffering tooth decay you had poor African and South American tribes men with relatively little dental problems. Pretty interesting. URL_0", "They also lived shorter lives back then for plenty of other reasons. So, they didn't have to eat for as long as we do."], "text_urls": [[], [], [], ["https://en.m.wikipedia.org/wiki/Weston_Price"], []], "score": [28, 12, 11, 8, 3]}}, {"q_id": "6ftsaw", "category": "Repost", "title": "Why do batteries need to be facing opposite directions?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dikvhpb", "dikvn0d", "dikvgyo"], "text": ["It makes manufacturing slightly cheaper by allowing a shorter length of wire (or simply a metal shunt) between batteries connected in series.", "They are usually wired in series and the cover or holders have springs or metal tabs that connect the batteries top to bottom. AA or AAA , C and D batteries produce 1.5 volts, so two in series gives us 3 volts, four in series 6 volts, six in series 9 volts, etc. Making you put them in upside down from one another reduces their product cost by shortening the path from one battery to another.", "It is primarily for design purposes. By alternating the direction they don't have to have the wires cross over one another."], "text_urls": [[], [], []], "score": [6, 5, 4]}}, {"q_id": "6fudn9", "category": "Repost", "title": "Why does glue not get hard and stick to its original container?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dil10lj", "dil1ufi", "dil11as"], "text": ["Often it is the case that water is acting as a solvent, so as to prevent the glue from solidfying into a self-stuck mass. The amount of air inside the container is insufficient in the short term to evaporate that water. Once you've applied the glue to some surface, it can more readily interact with the air and lose its water content.", "Glue needs a reaction to solidify. Superglue reacts with water, PVC glue melts the PVC it's in contact with, and other glues generally have a solvent (like water in Elmer's glue) evaporate leaving behind the solid glue. So the short answer is that the container keeps whatever reaction is supposed to happen from happening. If you left the cap open for example, water (in the form of humidity) could get into a superglue bottle and react with the liquid glue.", "because the container is (supposedly) sealed, so the solvent (ie, water) in the glue cannot evaporate."], "text_urls": [[], [], []], "score": [74, 26, 8]}}, {"q_id": "6fvtu5", "category": "Repost", "title": "Restaurants brag that their food is never frozen. How badly does freezing food really affect taste and quality? Or is it more of a marketing thing?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dildbff"], "text": ["it all depends on the food and how it was frozen. If food is frozen slowly, then ice crystals can form in and around it. These crystals damage the food and cause unpleasant textures. The act of thawing can hurt as well. Vegetables lose moisture as they thaw. however, typically this is a marketing gimmick. When flash frozen food loses very little. The implied message is that \"Our food is very fresh\" which isn't necessarily true either."], "text_urls": [[]], "score": [4]}}, {"q_id": "6fx6y6", "category": "Repost", "title": "Why do Homeowner Associations hold such tremendous power?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["diloulq", "dilou08"], "text": ["Because you voluntarily enter the agreement. No one forced you to buy the house, and you may sell the house according to the rules you yourself agreed to when signing that contract. They wield the power the contract gives them, and can pretty much put in whatever they like as long as it doesn't conflict with existing law.", "HOAs are entirely voluntary. If you don't want to join one, you simply don't purchase property governed by an association. That'll be pretty hard to do if you want to live in a place with shared property (like a condo building), but it's quite easy if you want to live in a house. There are plenty of horror stories about HOAs on reddit, but the good that a lot of them do goes mostly unnoticed."], "text_urls": [[], []], "score": [5, 5]}}, {"q_id": "6fxu7m", "category": "Repost", "title": "Statute of limitations - why?", "title_urls": {"url": []}, "selftext": "Was just reading a news arrival about a Japanese murderer who has been on run for 45 years and their statute of limitations for murder (15 years) had been abolished in 2010.... My question is why is the statute of limitations a thing in some countries? If someone is caught and evidence proves it was them they should be able to get convicted 1 year or 70 years later?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dilvab7", "dilur5s"], "text": ["The statute of limitations is in place because as people age, memories become less accurate and more prone to influence. Being able to find witnesses for an alibi Also becomes less realistic. Imagine having tok explain where you were on 5/4/1987. Also, physical evidence deteriorates and being able to refute evidence using forensic tests becomes less realistic or accurate. There are a few other factors, but the main point of a statute of limitations is to ensure that a defendant has a realistic opportunity to defend themselves effectively against the charges being filed.", "Let's say someone commits a crime and doesn't get caught. They get nervous, decide to clean up their life, and go legit. Twenty years pass and they have a family and a stable, society-improving job when someone finds out about the crime. At that point, does punishing the crime help anyone? No. Society is down a productive worker and a good parent for rigid, ideological dogmas of justice. Everyone is worse off if you punish that crime. If the guy doesn't go legit, he continues to commit crimes. Eventually he'll be caught, and by that time he'll have enough crimes on his record to go away for a long, long time, even if some of the earlier ones fall by the wayside. That's why. It's to encourage people to go legit even if they never turn themselves in."], "text_urls": [[], []], "score": [23, 17]}}, {"q_id": "6g3vfi", "category": "Repost", "title": "How exactly does fat exit my body after a workout?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["din9bdi"], "text": ["Fat (triglyceride) is made up of Oxygen, Hydrogen and Carbon. When 'burned', the fat is combined with Oxygen from the atmosphere to create CO2, which you exhale. About 85% of the weight you lose is exhaled as CO2. The remaining ~15% is turned into water, which you expel in your urine."], "text_urls": [[]], "score": [8]}}, {"q_id": "6g60l1", "category": "Repost", "title": "Why do birds fly in front of cars?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dinsfy2"], "text": ["Meanwhile on BirdReddit... Why do big hunks of rolling metal squash thousands of us every day for no reason?"], "text_urls": [[]], "score": [3]}}, {"q_id": "6g7uo7", "category": "Repost", "title": "How can we visualize our own galaxy , How do we even know it looks like a white round path from outside as we can see in everyday picture of Milkiway ? Or is it artist mere imagination ?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dio5kp1"], "text": ["You answered it yourself. Any picture of the milky way that isn't of the night sky is an artist's rendering, or a computer rendering. Now, some random person isn't flipping paint on a canvas willy-nilly, no. These renderings are very accurate. Astronomers have use various techniques to measure the distance to stars, with more accurate distances as techniques/technology improves. These measurements have been analyzed and we have found that the stars grouped up in the arms of a spiral galaxy. This gave us the ability to approximate an image of the milky way, because, even though we know how far the stars are, remember, it takes millions of light years for some star light to reach us, so their positions may not be accurate. So, the artist or computer may fudge something, but the end result is close enough that I don't think anyone cares."], "text_urls": [[]], "score": [3]}}, {"q_id": "6gbr95", "category": "Repost", "title": "Why does a word start to sound weird after saying it multiple times?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dip0xl8"], "text": ["Because it begins to lose your association with the idea it represents... IE - you say the word \"little\" and your mind immediately pictures something small.... if you continue to say \"little\" on repeat for a minute, it is just the sounds of the word coming out of your mouth and not the mental association with the idea."], "text_urls": [[]], "score": [5]}}, {"q_id": "6gce9q", "category": "Repost", "title": "Why do humans enjoy drinking hot and cold water, but find lukewarm water unsatisfying?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dip97ut", "dip98oc", "dip6ntt"], "text": ["My best guess is lukewarm = stagnant and stagnant in the wild means probably infected with all sorts of stuff. Well and spring waters are usually cold(ish). Not likely to come across hot water naturally so maybe the warmth is just comfortable and doesn't have to do with the water itself?", "I love luke warm water. It's easy to drink in large amounts quickly. Makes hydrating after a night of drinking super easy.", "I'm not so sure about hot water, but I do know that cold water sends the same signals to your brain that says that it is quenched. When you drink cold, salty water, the cold quenching sensation will actually overcome the thirsty sensation that people feel when you drink salty water."], "text_urls": [[], [], []], "score": [40, 29, 6]}}, {"q_id": "6gcgju", "category": "Repost", "title": "Before the 20th century, why did soldiers walk in a straight line formation towards the enemy?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dip788g", "dip6ot9", "dip9y9y", "dip7zd8"], "text": ["Short answer: Because battles are confusing as hell, and smooth-bore firearms are not terribly accurate. A smooth-bore infantry musket or musketoon of the 15th-19th century has an effective range against a man-sized target of 75m. Maybe 125m if you're a fine marksman with a quality weapon and good ammo. The best soldiers could fire 3-4 shots a minute at drill, with nobody shooting back at them. So a musket is really a piss poor self defense weapon against multiple attackers. You might get one of them, and then you have an empty gun vs however many are left to run up and stab your ass to death, and if they have horses you're super boned because you can't even run away. So you never, ever want to get caught alone. You want to be with your bros both because volley firing is more effective than one guy firing alone (more bullets equals more hits, and volleys are terrifying things to stand in front of) and because 100 guys with muskets and bayonets stand a much better chance fighting hand-to-hand as a unit than they do individually. This is where flashy uniforms, giant flags, bugles, crazy helmets, plumes, and other flamboyant costumes come in. Firing a musket is incredibly loud, and it produces a ton of thick smoke. 100 guys firing at once is basically an instant smokescreen. Unless there's a stiff breeze after 2 or 3 volleys you're going to be mostly deaf and blind. So you want your bros to be easy to spot in the smoke (bright red coats, huge silly hats, flags!) so you don't get left behind if they decide to move. tl;dr: 100 guys milling about alone in the smoke = cavalry meat 100 guys well-formed in ranks = killing machine", "Because they used muskets. Muskets were slow to load, and fairly innacurate because they were smooth bore. As such you fought in formations that let you volley attacks from a group of men toward another group of men increasing the odds of you hitting the enemy. These tactics were starting to be phased out by the American Civil war as they started to use rifles, breach loaded weapons and other advancements that increased individual effectiveness of a soldier but it was still mostly volley style attacking. Even WWI used this style of fighting when they were not trapped in the trenches.", "There's a lot of different factors there, but they basically boil down to a couple questions for each historical moment you're thinking of: How important is massed line infantry, and how effective are firearms against massed line infantry? So when the first firearms were invented battles were fought with big, dense formations of infantry protecting archers and important units. This was necessary for morale and communication purposes and for defense against other massed formations. You couldn't disseminate orders far and wide or micromanage small troop movements with radios and such so troops were grouped up where they could easily be commanded en masse and they were drilled to do their simple jobs automatically. Loose formations were safer against ranged attacks but they'd be split open by charges, especially from cavalry, and that leads to panic, breakdown, and exposure of the vulnerable parts of the army. Breaking those formations down was how you won; the majority of combat casualties in this kind of warfare were inflicted after the battle was already decided. A formation might only lose 10% of its members before it splits and loses cohesion but then cavalry can charge straight through, killing everyone in their path. At the same time early firearms were inaccurate and prone to failure and didn't pose such a huge threat to massed formations that they needed to spread out. As guns became more sophisticated and we got better at making effective use of them those big box formations became less effective. For a while warfare was dominated by muskets and pikes, and then the bayonet obviated the pike too. By the revolutionary and civil war we were already starting to experiment with more irregular formations as guns got better at mowing down dense formations, but the threat of cavalry was still there to keep troops dense. Machineguns and advanced artillery finally made line troops obsolete and learning that lesson the hard way is what made WW1 such a uniquely hellish war. There weren't really any counters to defensive emplacements like machineguns and they could chew through line troops easily so the fighting tended to grind down into trench wars where the only way to advance was to throw thousands of people into the meat grinder. Then tanks came around and could advance into machinegun and even certain kinds of artillery fire and offensive warfare became viable, but the sheer power of modern firearms to deny area and kill people en masse made line troops useless. Additionally, advancements in communication technology and more sophisticated training allowed armies to break up into smaller and more independent units with a more flexible chain of command, so you didn't need to have them all together anymore.", "Why march in a line? Because the goal was to create a literal sheet of lead. Why? Because as mentioned before, aiming as inaccurate. Why they did it in WWI after the hard lessons of the Civil War is the better question"], "text_urls": [[], [], [], []], "score": [111, 21, 11, 4]}}, {"q_id": "6gct39", "category": "Repost", "title": "Why does looking at/near the sun make me wanna sneeze?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dip9vhm"], "text": ["It happens in a certain group of people, it's commonly called [the Photic Sneeze Reflex]( URL_0 ). It's somewhat related to allergies (in that medication that you take to combat allergies will also prevent the sun sneezing)"], "text_urls": [["https://en.wikipedia.org/wiki/Photic_sneeze_reflex"]], "score": [4]}}, {"q_id": "6ggamo", "category": "Repost", "title": "Why does the power go out when there's a storm?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["diq16j2", "diq13kq"], "text": ["As said before, lightning strikes can trip the service line breakers. Also, trees can land on lines, wind can knock down power poles, junction boxes can get water in them, lines can get water in them (if poorly maintained), car accidents can take out power poles or junction boxes, wind can knock down lines and poles. Many, many reasons.", "If the power consistently goes out where you live in a storm you live in an area supplied by overhead power lines and they are probably being struck a lot. This trips circuit breakers and they are probably leaving them open till after the storm to prevent them constantly opening and closing again as this can wear them out over time."], "text_urls": [[], []], "score": [7, 5]}}, {"q_id": "6ghrk6", "category": "Repost", "title": "the differences between England, Britain, and the United Kingdom", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["diqd30a"], "text": ["[CGP Grey has a great video explaining this.]( URL_0 ) England is a country, Britain is an island, and the UK is a nation. The UK contains the countries of England, Scotland, Wales, and Northern Ireland. The island of Britain is home to England, Scotland, and Wales."], "text_urls": [["https://www.youtube.com/watch?v=rNu8XDBSn10"]], "score": [4]}}, {"q_id": "6gkiep", "category": "Repost", "title": "Why do we have nightmares?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["diqzgg5"], "text": ["Scientists aren't entirely sure why we have *any* dreams, let alone bad dreams like nightmares. There's a few theories, but nothing's been proven. Some psychologists believe dreams are our mind acting out fantasies, fears, and repressed desires. In sleep, our mind is unrestricted by the *superego*, the part of the mind concerned with morality and social rules. Sigmund Freud believed dreams were a \"royal road to the unconscious\". Some more modern neuropsychologists think dreams might have to do with our brain encoding information into long-term memory, and this is why dreams are often based around events that happened the day before the dream. But again, no one really knows, these are just hypotheses. The science is still in its infancy when it comes to dreams. But what we do know that is that we have dreams during a deep phase of sleep called REM sleep, and that if we sleep briefly but don't get to go into REM stage, our sleep will not be very restful and our brains will endure gradual damage if we go weeks and months without getting a proper amount of deep sleep every night. It's very important to consistently get 7-9 hours of sleep every night. Chronic sleep deprivation is bad for your health."], "text_urls": [[]], "score": [5]}}, {"q_id": "6gl94i", "category": "Repost", "title": "How did people clean their teeth before the invention of the toothbrush?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dir4kbl", "dir4ozh"], "text": ["Besides what u/stannywilson said, there was much less need for teeth-cleaning tools until the time of the Industrial Revolution. Before that, sugar and other sweet foods were much less common in the diet, and since sugar feeds the bacteria that cause tooth decay it was less necessary to clean teeth (this isn't to say it didn't happen, but it was less pervasive).", "Hiya. Medievalist nerd checking in! In the period I'm best versed in, someone wanting to look after their teeth could use a rag, wash their mouth out with vinegar or use a split twig (chew on it until the end got soft and bristly, then use those like a toothbrush). People sometimes carried little personal hygiene kits on their belt or in a pouch - the Norse left LOTS of these, and one such kit might come with a comb, an ear-spoon (ancestor to the modern q-tip) to get the gunk out of their ears, a toothpick... People were very much aware of using herbs to sweeten breath too. Having nice breath is mentioned in a lot of contemporary texts as a very desirable attribute, and they'd chew on anything that could offer that. Almost every household, great or small, would have a patch of garden with things growing in it that they could use to cook with, for medicine, pigments and dyes, to keep unwanted pests away or any of those important things. Mint isn't exactly hard to grow, and there's no shortage of other sweet-smelling options. In some very specific ways their oral health was actually somewhat better than ours. They ate much less sugar than we do, so decay and cavities were less common; remains that have been dug up usually show the teeth as *worn down* (or sometimes notched, especially women's teeth...she would have been using her teeth to help her hold her thread/pins/needles as she sewed and developed the classic \"tailor's notch\" as a result) rather than full of holes. People then were a lot like people now. They didn't have a clue what germs were, but they didn't necessarily LIKE being gross."], "text_urls": [[], []], "score": [5, 3]}}, {"q_id": "6gla5a", "category": "Repost", "title": "Why is it so hard to kill the remaining .1% of bacteria with disinfecting wipes?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dir4ok0"], "text": ["These companies don't advertise 100% bacterial elimination because they are protecting themselves against litigation. Let's say you have this super rare, super resistant bacteria that you introduce to a surface. You then use the anti-bacterial wipe to disinfect the surface. Then, you purposefully wipe that bacteria that you absolutely know was not killed onto your skin, and become mildly or even gravely ill because of it. If the advertisements said **100% of bacteria will be killed**, then you've got a lawsuit that could potentially be worth millions of dollars. Advertising **99%** instead removes the ability for people to sue based on super-resistant bacteria."], "text_urls": [[]], "score": [17]}}, {"q_id": "6gmg9s", "category": "Repost", "title": "Why do people stick a 'SOLD' sticker on a previously 'FOR SALE' house's billboard?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dirdee3"], "text": ["Because it's still an advertisement for the real estate agency, and it shows results. You see a \"sold\" sign and people can see that the agency is doing its job."], "text_urls": [[]], "score": [5]}}, {"q_id": "6gngxt", "category": "Repost", "title": "How do we keep from falling off the bed when we're asleep?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dirlf02"], "text": ["When you fall asleep part of your brain is still awake and functional. So you are able to maintain the minimum mental capacity required to keep you safe and alive. This involves a simple reflex to not fall off the edge of the bed."], "text_urls": [[]], "score": [3]}}, {"q_id": "6gph08", "category": "Repost", "title": "Why does 70 degree weather feel better than 90 degree weather, even though your body temp is 98.6?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dis2q8m"], "text": ["Your body is constantly generating heat. Heat is a byproduct of metabolism, and metabolism is basically all the chemical reactions that keep us alive. 90 degrees (or 32 for everyone else) is pleasant enough when you're not hard at work, when you can sweat freely, and when it's not too humid for that sweat to readily evapourate, and 60 feels fine when you're very hard at work too. Basically, you generate more heat than you need to keep your body warm when it's 90 degrees out, and that also begins to approach conditions where it's difficult for your body to shed heat quickly enough to maintain the proper temperature. Around 70 (21), that's a good balance, in general, for the heat generated at resting and working metabolism, countered by the body's natural cooling systems. TL;DR our bodies are little chemical furnaces and need the environment to be cooler in order to shed excess heat."], "text_urls": [[]], "score": [8]}}, {"q_id": "6gs1ys", "category": "Repost", "title": "why does the sun seem to move faster when it is setting?", "title_urls": {"url": []}, "selftext": "We sat watching the sunset last night in Cuba, and it took about 10 minutes to go from about an inch above the horizon, (from our perspective on the beach) to totally gone. Yet it will stay in the sky literally all day...", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["disl6jo", "disl7lv"], "text": ["It just looks like it is moving faster when next to the horizon, an optical illusion caused by lack of any reference in the sky", "Lack of a point of reference. When the sun is up in the sky and you look up at it (in it's general direction, never look directly at the sun), there are no points of reference by which you can gauge its rate of motion. When the sun is closer to the horizon, you now have points of reference (the horizon itself, and any other major features) that allows your brain to judge its speed."], "text_urls": [[], []], "score": [24, 6]}}, {"q_id": "6gyhpv", "category": "Repost", "title": "How is a microwave able to warm up food but not things like plastics, papers, glasses, etc.?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["diu39ye"], "text": ["Microwave oven work through something called Dielectric Heating. It only works on stuff that is made of a Dielectric Material. When a dielectric material is in a magnetic field, the molecules turn to face the direction of the field. A microwave from the viewpoint of a stationary molecule is a rapidly changing magnetic field. So the molecules starts turning quickly back and forth to follow it. This rapidly turning is the heat the microwave causes. Things like water, fat and sugar are dielectric materials, so they heat up. Things like glass and some plastics are not dielectric materials so they don't heat up. Often a material is dielectric because the molecule has more positive charge at one side then on another side. Things like glass molecules are made out of molecules that don't have any built up charge in any particular place."], "text_urls": [[]], "score": [9]}}, {"q_id": "6gykbb", "category": "Repost", "title": "What determines the value of currencies around the world?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["diu41xe", "diu52n2"], "text": ["Nowadays, virtually every currency is what we call \"fiat currency\". It means that is not backed by an actual good (i.e. gold or silver) but by a government. Economic actors (people, businesses, markets, etc) put trust in governments to be able to provide currency because of their control over a country's economy and their ability to tax it. The value of a currency relative to its area of use is determined essentially by how fast the Central Bank (the government issuer of currency) releases it. This is done by setting an interest rate which determines the cost of \"new money\" put in the economy. When the interest rate is equal to the growth rate of the economy, the currency's value is stable. When the interest rate is lower than the growth, the currency enters the economy too fast for the economy to generate the corresponding value. The currency is then less valuable, prices go up. This is called inflation, the reverse situation being deflation. Both inflation and deflation have economic strengths and weaknesses, it is the job of Central Banks and political technocrats to determine how to use these tools for the benefit of the country. As to the value of a currency relative to another, currencies are traded on markets know as Foreign Exchange Markets or FOREX for short. It is then a classical game of offer and demand, the exchange rate is the result of buyers' price meeting sellers' price. The fluctuation of exchange rates is the result of the perception of the different countries economic strength and perspective.", "The really short answer is the market forces of supply and demand. The long answer is far too complex to explain in an ELI5 format due to an virtually unlimited amount of variables that impact currency movements. The shorter answer would be interest rate differentials between different economies. The answer i'm providing assumes a long term outlook on currency movements, short term can be completely random or caused by something as simple as a Trump tweet. Here's how this works in ELI5 fashion, Let's say you and your neighbor are both farmers, he grows oranges and you grow apples. For the past 2 years it looks like he has been growing more and more oranges meanwhile your harvest has only gotten worse. You can sort of afford for this to continue but why would you when you could get some extra oranges for no added effort? i mean you were going to farm anyway what does it matter what you grow? You decide to switch from apples to oranges and speak to your neighbour about exchanging some apples for oranges and he tells you that he would happy swap with you but at a 2 apple seed to 1 orange seed ratio. You think this guys an idiot and out to rip you off and as you're leaving you notice your mate from across the road is also coming to the neighbour with his apples. You go back to the orange dealer the next day and now he demands 3 apple seeds for 1 orange seed. You tell him to go stuff himself. This is how and why currency movements occur from a fundamental perspective. Just change the farm to a thriving economy, oranges to US dollars and apples to Australian dollars and you have the AUD/USD exchange rate. Oranges are safe to farm (risk free, investors love not losing money) so there's little downside from changing from apples to oranges and it makes sense to because it adds no extra work for you but you have more food to eat (better returns on investment or higher interest rate). However your sneaky mate from New Zealand has noticed this as well and decided to do the same thing (increasing demand) which essentially made it more expensive for you to invest because mr orange grower realises his oranges are worth more than he thought. Multiply this concept by however many investors there are in the world and you have the reason as to why currency values change. One thing to note is that there doesn't need to be an increase in demand for oranges for the exchange to move. What if there was some sort of vegan Apocalypse and the zombies have eaten all the oranges? suddenly the world is full of apples and zombies but in any case the oranges are now worth more apples because you need to steal them off vegans"], "text_urls": [[], []], "score": [12, 4]}}, {"q_id": "6gzdgs", "category": "Repost", "title": "why did older TV show have laughing tracks.", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["diu8q73"], "text": ["Because they were originally filmed in front of a live studio audience. Producers believed that audiences would miss laughing along with others and felt it would make for a better experience. Contagious laughter works but using the same track and tacking a laugh on every joke eventually backfired."], "text_urls": [[]], "score": [6]}}, {"q_id": "6h09gm", "category": "Repost", "title": "Where did the stereotype for Vikings come from?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["diufmdk", "diuhqjf"], "text": ["From the people whose monasteries they burned down and stole from. *Norsemen* were relatively peaceful. All vikings, by definition, were warlike because viking was a job description for pirates, not a society.", "Most of it is not really a stereotype. The word \"Viking\" in old Norse means \"raider\" or \"pirate\". So all vikings were the portion of the Norse population that were very violent as they raided other communities. Thus they are pillagers of lands. They were bearded traditionally, so I am not sure why you think they were clean shaven. Almost no one in Europe north of Italy was clean shaven till WWI as a cultural norm. They were taller than many other European groups, though they were not 7ft tall on average. Horned Helmets is a false stereotype. That is from Wagner's Opera \"The Ring Cycle\". They were not as violent as we see them in modernity, but they were more violent than most of the rest of Europe at the time. It was common for disagreements to be settle with one on one combat. It was common to kill each other by accident and they had strict cultural rules about reporting such incidents. And of course they went raiding nearly yearly due to having poor climate and more populations than they could provide for natively. The notion of them being a peaceful bunch did not happen until late in their history when they switch their seafarers to being traders primarily instead of raiders (though they still raided) and they started to convert to Christianity. While they still worshiped their war gods they were very violent. As for hygiene there is not really a stereotype that they had bad hygiene, though all seafarers would have to some extent."], "text_urls": [[], []], "score": [7, 4]}}, {"q_id": "6h0isr", "category": "Repost", "title": "Why are non-human or non-uniquely-identifiable figures allowed to run for office in the UK?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["diuhwdx", "diuhxkc", "diui09j"], "text": ["They are all people running a campaign using pseudonyms, which are allowed so long as they aren't offensive or likely to cause too much confusion. For example, Lord Buckethead was a guy named Jonathan David this time around and when they counted votes the votes were for \"Jonathan David, known as Lord Buckethead.\" Similarly, Elmo is a guy in a large Elmo suit. The person who is actually running has to register and submit identifying information to become a valid candidate.", "Lord Buckethead is a real human, and evidently a UK citizen. There is no law against legally changing your name to something silly. There is no law against wearing a silly costume when campaigning. This person is taking advantage of these flexible rules.", "Yes you do have to be a real person to run for MP. You are allowed to run under a pseudonym though, which is why Lord Buckethead was allowed to run as Lord Buckethead instead of whatever his real name is. You don't strictly have to be a UK citizen. Irish and Commonwealth citizens are also allowed to run for MP."], "text_urls": [[], [], []], "score": [11, 9, 5]}}, {"q_id": "6h10v5", "category": "Repost", "title": "Why RAM is necessary in PC? Why not some part of Hard disk to be used as RAM?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["diunjt7", "diulyc1", "diumf51", "diumgb3"], "text": ["Imagine that you want a bag of chips. They are currently in your pantry. Now, each time that you want to eat a chip (or a handful, I'm not here to judge) you have to walk to the pantry and get a chip. There's tons of storage space in the pantry so you can put all kinds of chips in there however it takes you forever to eat your chips and you're missing out on whatever you might be watching on TV. Of course, we don't do this, instead we bring the whole bag of chips and whatever else that we need and put it on the coffee table next to us. Now we can eat those chips more easily. We can't keep as much stuff there but we generally don't need a whole lot of other things at the same time. You even have room for your chip dip and your soda. It's all easy to get to and much faster. When we're finished, we put the chips back into the pantry, the dip back into the fridge, and whatever else we had. The coffee table is now empty again since it's not for permanent food storage. Your computer works in a similar fashion. The chips are whatever program or data that you're currently working with (or on). We could keep going back to the hard drive for it, but like going to pantry for every chip, that's not very fast or efficient. So your computer loads up whatever it's working on into RAM for quick and easy access. Now, like your coffee table, RAM is not for permanent storage just for quick access so when your computer shuts down it actually just makes everything on the coffee table disappear; it just disappears into nothing and is not saved anywhere (yes, there are exceptions to this, but for our purposes this will suffice). Also, if you get a bigger coffee table, then you can snack on more things at the same time. The same goes for more RAM. If you get more RAM then your PC can snack on more things at the same time unless Chrome sneaks in and gobbles it all up first.", "It can be, that's what virtual memory is. The problem is, hard drives (even SSD) are a lot slower than RAM. RAM also has its own dedicated data bus, whereas the hard drive will share its data bus with at a minimum other SATA devices.", "The reason it's \"necessary\" is because of the speed. From the article [The Pathologies of Big Data]( URL_1 ) Hard Disk speeds can be 150,000 times slower at random read and write access than RAM is ([Figure 3]( URL_0 )).", "In theory it can. When there are not enough space in RAM memory operating system cretes special file called Swap. It will act as RAM, but will be orders of magnitude slower than proper RAM memory. In good old Win XP days allocated swap size had to be atlest 2x the size of total available RAM space."], "text_urls": [[], [], ["http://deliveryimages.acm.org/10.1145/1570000/1563874/jacobs3.jpg", "http://queue.acm.org/detail.cfm?id=1563874"], []], "score": [39, 4, 3, 3]}}, {"q_id": "6h1a0m", "category": "Repost", "title": "What happens when a computer file is deleted? Does the data actually vanish from existence or does it continue to exist in a dormant state?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["diuobtu", "diuoffh"], "text": ["The operating system removes any reference to the file and marks the area that the file took up as free. The file may or may not eventually be overwritten by new files. Files can be recovered before they are overwritten. You can also securely delete a file, and the space that it takes up will be immediately overwritten, making it nearly impossible to recover.", "depends... on a magnetic disk drive, typically all it does is \"forgets\" where the data was. its like taking the street number off your house. there are recovery tools that will read the raw data on the drive. This is relative childs play, you can get free apps that will do this level of recovery. Alternatively, there are format programs that will actually WRITE 0's and 1's over the drive multiple times to completely eliminate any residual image of the former data. It will do it multiple times because if your REALLY ambitious with advanced recovery software, it may be able to even detect what it was \"before\" the last overwrite. flash drives are the same, but its much easier to just reset all of the bits, theres no residual magnetic charge."], "text_urls": [[], []], "score": [3, 3]}}, {"q_id": "6h1wat", "category": "Repost", "title": "Why isn't there a disease that's the opposite of depression?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["diutibb", "diutn7z", "diuudrr"], "text": ["There sort of is. Just like there are depressive episodes, there are manic episodes. During a manic episode you may feel euphoric, like you are super powerful, you can do anything. You make big plans, you're gregarious, you're thrilled, excited.", "There sort of is, frequently described as [\"Mania\"]( URL_0 ). Mania is characterized by extreme hyperactivity and arousal (not necessarily the sexual kind), frequently along with delusions stemming from the overactivity of the relevant brain sections.", "The opposite of depression isn't 'joy' or 'happiness'. Those are the opposites of 'sadness'. Depressed people typically don't even feel sad. They experience 'anhedonia'. Depression is about numbness, exhaustion, and emptiness. The opposite of that is closer to mania."], "text_urls": [[], ["https://en.wikipedia.org/wiki/Mania"], []], "score": [9, 5, 5]}}, {"q_id": "6h2d1j", "category": "Repost", "title": "what exactly are knotted muscles in your back and where do they go when massage therapists work them out?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["div324v", "div06u1"], "text": ["Doctor, and D.O. here (we kinda love this type of stuff, and are somewhat like massage therapists that wasted more of our lives lol). A knotted muscle is like what these guys are describing, it's just tight when it shouldn't be. The back is a good place to think of an example to conceptualize it, but you also have to understand that EVERYTHING in the body is connected to (and therefore impacts) almost everything else. Think about a muscle in your lower back that starts to contract (when it kinda really shouldn't), no big deal right..? Well sort of yes a big deal! 1st off that means the spine gets pulled to that side, specifically 1 of the vertebrae will be rotated or bent to that side, which puts weird stress/strain on the vertebrae above and below (can cause pain and weird tingling), additionally that muscle also (lets say) attaches to your hip... when it tightens it tries to rotate your hip bone up, now that stretches your hamstring (which doesn't like to be stretched past a certain point) so your hamstring now starts to tighten up and contracts too. Now you have a small (ish) issue with 1 muscle group that has created an issue of pain/tension/bony immobility from your lower back (or higher), through your pelvis, down your thigh, to your knee (or lower). Fortunately for us we have learned that several things can calm those muscles down, #1 being pressure applied to the muscle (or surrounding muscles), somehow our muscles evolved that pressure on/around in gentle and direct focused ways will cause them to relax. Another way almost everyone uses/knows about, stretching! When you stretch a tight muscle it will cause at least SOME of those fibers to relax because they need to relax or they tear (that's why you don't wanna stretch SUPER aggressively if you have a tight muscle, but gentle stretching helps!). Another less well known way is to use an opposing muscle. Going back to our tight hamstring example, if you gently but forcefully use your quadriceps (against resistance is best) it will help your hamstring to relax. Our body is smart enough to know that you shouldn't really use two opposing muscles at the same time (quad/hamstring, tricep/bicep) with the same force, otherwise you wouldn't do anything (this is kinda different for fine motor movements but lets not make this discussion longer than it is :P) sooooo using your quad automatically causes your hamstrings to start to relax, and if you repeat that, it will continue to help it relax. BUT you didn't solve the problem in your back!! So the tight hamstring will come back... this is why (again) everything in the body is connected, and also why some people get the same tight muscles (or the same bones that \"pop\") over and over again. Because they treat one of the resulting issues, without treating the main one. Hope this helps!! And hope it wasn't TOO long and boring.", "I'm not a doctor. I believe that knotted muscles are muscles that are contracting when they should be constricting. Think of making a clenched fist. A massage therapist would be working to relax your fist to extend the fingers out, with the fingers being the muscle itself. Again, not a doctor."], "text_urls": [[], []], "score": [156, 3]}}, {"q_id": "6h2q1c", "category": "Repost", "title": "what is a terraflop? What advantages does this bring to me? How does this correlate the new Xbox one x?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["div2sty", "div1p7b"], "text": ["FLOPS is a measure for FLoating point Operations Per Second. This measure indicates the speed at which a computer processor can chug through calculations. \"Tera-\" is a prefix meaning \"1000 times Giga-\". You might have heard of Gigabytes or Gigahertz? Those are just the \"giga\" ordinal for bytes and hertz. \"Giga-\" means \"1000 times Mega-\", \"Mega-\" means \"1000 times Kilo-\", and \"Kilo-\" means \"1000 of something\". So: 1 Teraflops = 1000 Gigaflops = 1,000,000 Megaflops = 1,000,000,000 Kiloflops = **1,000,000,000,000 flops**. So a 1 Teraflop processor can calculate 1 trillion operations per second. For comparison, there exist supercomputers that run upwards of 30 *Peta*flops, where 1 Peta = 1000 Tera. Quite the head-spinner, that one. :) --- **How does that benefit you with the Xbox One X?** Supposedly, the more FLOPs, the better. The Xbox One X will be coming out with a GPU that processes at 6 teraflops, or \"TFLOPS\", meaning it comes close to the performance of an nVidia GTX 1070 ([which operates at 6.5 TFLOPS]( URL_0 )). That should produce some decent high-res visuals at a good framerate, if the console is all it's chalked up to be. Edit: silly me, I forgot Giga! And I call myself a techie. :(", "FLOP stands for FLoating point Operations Per second. Graphics and physics calculations often use floating point numbers instead of integer numbers. So Flops is a rough measure of how much graphics or physics calculations you can do. It follows the SI standard of units which goes kilo, mega, giga, terra, peta, etc. So one terraflop means a trillion floating point operations a second."], "text_urls": [["http://www.anandtech.com/show/10336/nvidia-posts-full-geforce-gtx-1070-specs"], []], "score": [6, 3]}}, {"q_id": "6h6wqp", "category": "Repost", "title": "So why hasn't the water crisis in Flint, MI been fixed yet?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["divyfdl"], "text": ["Its technically been \"fixed\" for well over a year - which is when lead levels in the water returned to normal. You still hear about it because they are still replacing the city's pipes and it won't be considered fixed until all of the pipes have been replaced - which is a very expensive, time consuming process. What happened is that the city's pipes are made out of lead. This isn't uncommon - lead pipes were widely used until the 80s and Flint's water infrastructure is significantly older than that. Ordinarily lead pipes are fairly safe. Lead only leaches out of very old pipes and even then usually in amounts that don't pose a public health risk. However, for a period of about 13 months Flint used water from the Flint River that had an unusually high natural level of chlorine in it. That chlorine caused damage to the city's pipes, causing them to leach lead into the water supply. Once Flint switched off of the Flint River water, levels of lead in the water slowly returned to normal. However, the city is still replacing *all* of the water mains out of an abundance of caution. This is a very long process because it involves digging up every street in the city, removing the existing water pipes, and then replacing them with new pipes. For the same reason, its also a very expensive process. Due to the difficulty and cost of the project, the current budget of ~$50 million per year will see the project completed sometime in 2020. If the water posed a current health hazard you would likely see more money going to it to move that timetable up, but since the water is currently safe to drink the project is just being treated like any other large public works project."], "text_urls": [[]], "score": [4]}}, {"q_id": "6h7ax2", "category": "Repost", "title": "What is \"jury nullification\" and what is its purpose?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["diw0qa4", "diw0ucl", "diwjgvf", "diw9hiw"], "text": ["There is no \"purpose\" to jury nullification as it is just a side effect of the jury system. The jury might decide that a defendant is guilty yet refuse to convict them because they don't agree with the law. This isn't intended and would generally be considered a perversion of justice, but the jury decision stands regardless.", "It's a finding that doesn't actually match the jury's belief, for instance if they conclude a suspect is guilty but find him innocent. It can have a variety of 'purposes' such as disagreement that the law in question is just. A jury might find a person innocent of possession charges, even if they know he is guilty, because they don't believe possession should be illegal, for instance. Or they might find a person guilty despite knowing he/she is innocent because they have some animus against the defendant. To be clear when it comes to 'purpose', it is a very contentious subject, and something you will find many legal professionals considering a violation of the Juror's oath, but it is also not something that can necessarily be prevented or necessarily should be prevented.", "CPG Gray actually did a really great [video]( URL_0 ) on this awhile back. Edit: a missing space", "The \"what\" of jury nullification has already been answered. And as others have said, it doesn't have a specific purpose: it's just a side effect of trial by jury. As to whether or not it's a good thing, that depends on your point of view. In favour of jury nullification, juries may acquit people because the law they're accused of violating is a stupid law. For example, suppose it were a criminal offence to wear a green shirt on Fridays: juries would probably nullify that one all the time, until the law enforcement agencies stop trying to enforce it. In effect, jury nullification can provide a sort of sanity check. Arguing against jury nullification, it has been used in the past in very sinister ways. For example, go back a few decades and you'll find several cases of all-white juries in parts of the Deep South finding whites \"not guilty\" of the murder of blacks despite overwhelming evidence."], "text_urls": [[], [], ["https://youtu.be/uqH_Y1TupoQ"], []], "score": [15, 11, 10, 7]}}, {"q_id": "6h8qsr", "category": "Repost", "title": "Why do airplanes flying above me appear to be going so slow even though they are traveling several hundred mph vs my slow walking pace?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["diwdabi", "diwdkyo"], "text": ["well, how do you gauge their speed? tiny dot in a big sky, no frame of reference. if they travel a mile at their distance, it might be a fraction of a degree change in your perspective. with nothing to mark the change against. Basicly, they appear to be going slow because your not used to judging speed of objects in that are that far away.", "Because the sky is huge and your pavement is small. [This may help explain.]( URL_0 )"], "text_urls": [[], ["https://m.youtube.com/watch?v=OXypyrutq_M"]], "score": [4, 3]}}, {"q_id": "6h909s", "category": "Repost", "title": "Why is depression a thing, but the opposite isn't? In other words, why is it chemically possible to be depressed, but you never hear of people who are chemically so happy that basically nothing bad can get them out of the state of euphoria?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["diwfoda", "diwfn9w", "diwg1l3"], "text": ["That would be [mania] ( URL_0 ). It is not an exact mirror image, but states of heightened emotions, energy, decreased need for sleep and hyperactivity do exist and they present with several different disorders. (Bipolar tends to be the best known one)", "The opposite is a thing. It is called being manic. People have the condition on its own, and in combination with depression when they are bipolar.", "The opposite of depression isn't 'joy' or 'happiness'. Those are the opposites of 'sadness'. Depressed people typically don't even feel sad. They experience 'anhedonia'. Depression is about numbness, exhaustion, and emptiness. The opposite of that is closer to mania."], "text_urls": [["https://en.wikipedia.org/wiki/Mania"], [], []], "score": [17, 7, 5]}}, {"q_id": "6haol4", "category": "Repost", "title": "Why do painters wear all white?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["diwwurk", "dixgdsu"], "text": ["Traditionally white clothes were worn by painters as it was the easiest color to clean as it could be bleached.", "It also helps prevent cross contamination, ie your less likely to brush up against things if you know you have paint on you."], "text_urls": [[], []], "score": [116, 13]}}, {"q_id": "6hatk9", "category": "Repost", "title": "How does Rain have a \"smell\" if it's just water?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["diwvosr"], "text": ["Plants release oils into soil during dry periods. These are released during rainfall, and they smell. Air pores in soil release bubbles when water hits them. From lightning, the air smells like ozone, and lightning usually comes with rain. It's called [Petrichor]( URL_0 )."], "text_urls": [["https://en.wikipedia.org/wiki/Petrichor"]], "score": [5]}}, {"q_id": "6hcbvh", "category": "Repost", "title": "how does computer performance work? how do things like processor, chip, RAM etc come together to make a computer slow/fast?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dix8b6k"], "text": ["There's one component that heavily influences your experience with a modern computer, the hard drive. Always get an SSD Modern processors are plenty fast for reasonable workloads, unless you're video editing or number crunching you're probably not CPU limited Modern RAM is cheap enough and fast enough for modern workloads. Chrome will gobble up all your chips no matter how many you give it, but when it runs out of chips how quickly can it get more? When you run out of space on RAM you have to go back to your primary storage, traditionally a HDD which was made of spinning discs, now an SSD which is a really big SD card that lives in your computer. An SSD has a latency measured in nanoseconds while a hard drive takes 7 ms to reach what you need to read. The SSD can also read the data out 10-1000x faster than the spinning discs can, this leads to things opening quicker, super fast boot, less lag, even faster browsing because Chrome needs to keep running back for more space Having more performance does you no good if you won't use it. An i7 is of no use to someone who uses Word to write christmas cards once a year, a strong GPU is of no use to someone who just watches Netflix. Unless that component is limiting the performance then upgrading it yields no noticeable benefit. Your primary storage is almost always limiting maximum performance so the biggest gains are there"], "text_urls": [[]], "score": [3]}}, {"q_id": "6hept6", "category": "Repost", "title": "Where does the Layout for QWERTY keyboards come from?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dixq5a7", "dixoxq2"], "text": ["The QWERTY layout first appeared in 1874 on the Sholes and Glidden typewriter later renamed to the Remmington No. 1 (yes the gun manufacturer). We do not have the internal documents describing the development of this new model of typewriter and the development of the QWERTY layout. However we do have the advertisements and marketing documents which claim that the typewriter is much less prone to jamming when typing fast. It is still a debated topic to this day how the QWERTY layout helped prevent jams or if it helped at all. We do know that other typewriter manufacturers adopted the QWERTY layout but we again do not have the documents describing why they did so. The only surviving records describing the decision to use the QWERTY layout was after it had become popular and standardized so people did not have to relearn to type when getting a new typewriter.", "Back in the day when type writers were used, letters were arragned in alphabetical order. But when writing fast mechanisam got stuck becase letter who were used the most were close together. So some french guy i think aranged them in order where to most used letters were the furthest away from eachother. And till today that desing stayed even doe its primary use is obsolete."], "text_urls": [[], []], "score": [9, 6]}}, {"q_id": "6hhv30", "category": "Repost", "title": "Why have there been no supersonic air travel services since the Concorde was decommissioned?", "title_urls": {"url": []}, "selftext": "One would imagine that modern technology could make the service profitable in ways that we couldn't with the Concorde's 1970's technology. Kind of strange that airline travel speed hasn't improved much in the past 60 years.", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["diyfjqu", "diyfgg4", "diyfzh9"], "text": ["Supersonic aircraft a expensive to maintain, expensive to fly, and even more expensive to design for consumer level travel. Also, flight paths are limited because of the sonic boom, typically can't fly over populated areas at speed which limits usage to niche markets. They also tend to hold less people than larger aircraft that travel slower.", "The feats of modern technoogy still haven't changed the laws of physics. The faster you go, the more air resistance you get and the more fuel you have to burn. Fuel costs more than it did back in the 80s", "One big factor is that people get unreasonably snippy when you break the sound barrier above their house multiple times a day every day of the year. It's basically just Nimbyism, but airlines don't really have a choice but to give in. That means you can only fly from (and to) airports too far from civilisation to be useful."], "text_urls": [[], [], []], "score": [17, 8, 3]}}, {"q_id": "6hj1zf", "category": "Repost", "title": "Why does the United States continue the tradition of a two party system?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["diypc1d", "diyqaiy", "diypkqq", "diypbio"], "text": ["Because those 2 parties have an obscene amount of power / influence, and they use that power / influence to prevent others from trying to get a piece of the pie. Why would either party want to change a system which benefits them massively?", "The two parties in the US are not actually a part of the government. They are civilian organizations that unify to support a candidate during elections. It should also be noted that the two party system is a result of the first past the post winner take all system. The specific parties will shift periodically over time but there will always be a winning party and a primary challenger in such a system.", "Gathering in a party allows you to access much greater resources, outreach, and political support than being independent. The parties coalesce into a big group representative of a general method of governing. The thing is, if you have all these independents, some can gather before a poll to make a small group of like-minded politicians. They combine their political support bases and are able to win more elections. Then, the group grows, and opposing view groups form as a result. Here's where two party comes in: Some parties will always be more popular than others. Say A, B, C, and D are the parties. In many elections, D is somewhat smaller and never wins. So they go into one of the bigger parties that agree with them. Then, A and B can be a little bigger. C suddenly is losing more and more to these behemoth parties. C then dissolves into the party that shares its views. All's left is A and B. Nobody builds a party to oppose them big enough, because they will never reach the level of these other guys. Sometimes, party B will resurrect and fund party C a little, to get voters away from A, if C is more similar to A but not quite, just so that the A votes get split between A and C and thus B wins. EDIT: [this]( URL_0 ) explains it all.", "Two party systems are often the result of a Single Member Plurality electoral system aka electoral college. Changing the voting system will probably change the party system since people who may want to vote for smaller parties will no longer believe that their vote will go to \"waste\"."], "text_urls": [[], [], ["https://www.youtube.com/watch?v=s7tWHJfhiyo"], []], "score": [12, 5, 4, 3]}}, {"q_id": "6hjdix", "category": "Repost", "title": "why is 18 considered the age when you become an adult(not 17 or 19 or 20)?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["diys3l6", "diys4zx", "diyssog"], "text": ["\"In the Middle Ages 21 was considered the age of adulthood because that\u2019s when young men were capable of wearing a full suit of armor. 21 stuck until the 20th century. The need for soldiers for WWII, Korea, and Vietnam wars saw 18 years olds drafted and an outcry that they could serve their country but not vote. This led to passage of the 26th amendment lowering the voting age from 21 to 18 in 1971. Source: Children and the Law class in law school and accompanying casebook\" -u/Sneekey", "It's arbitrary. In Japan the adult age is 20, and its privileges are unanimous. Driving, voting, drinking, all the same. Most adult ages will be between 17 and 21 because it's the end of the teenage years.", "It cracks me up when people refer to 17 year olds as children and 18 year olds as adults. It's utterly arbitrary but people swear to God there is a defining line at that 18th birthday."], "text_urls": [[], [], []], "score": [35, 10, 4]}}, {"q_id": "6hjobh", "category": "Repost", "title": "Why can we (humans) only selectively block out visual stimuli(close our eyes) but have no was to inhibit/delay/shut out tactile, olfactory or audio stimuli?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["diyv84r"], "text": ["The main reason we can close our eyes or blink has to do with maintaining the moisture of the eyeball, and protecting the eye from things like sand, sweat, etc. We can also blink to help remove foreign debris from our eyes. Our ears and nose have little hairs that essentially do the same thing. Long story short; our lids aren't closeable so that we don't have to see things. They're there to protect our eyes, just like our ear and nose hairs are. So, to reply to your further comment: we don't have a way of closing our nose or ears because for their functions, we have no biological need to."], "text_urls": [[]], "score": [7]}}, {"q_id": "6hjuf3", "category": "Repost", "title": "How does vitamin D work? Is it a real substance that comes from the sun or is it created by our body?", "title_urls": {"url": []}, "selftext": "I'm pretty sure it's just magic.", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["diz68d0", "diyw1pk", "dizfa3j"], "text": ["Vitamin D is a real substance. It doesn't \"come from the sun\" at all, the sun just sends energy... Your skin is full of oil and fat and stuff. One of the things it contains is cholesterol. When cholesterol is exposed to Ultraviolet light, particularly \"UV-B\", the incoming photons knock some of the atoms in the cholesterol molecule around. The result of that knocking is Vitamin-D. Now unlike photosynthesis, which only happens in special sub-components of cells in plants, the Cholesterol- > Vitamin-D thing can happen anywhere. Like if you put a blob of it out in the sun on a dinner plate it would convert. You sort of ooze out cholesterol, and then it gets converted into \"vitamin D lotion\", that soaks back into your skin. So there are some surprising things here to \"Get Vitamin-D from the sun\": - Depending on where you live, you may only be able to make significant quantities around noon (or 1pm on Daylight savings time) because that's the only time of the day that enough UV-B can get through the sky. The further towards the poles you get the smaller the window. - If you shower or bathe too soon before you sunbathe (like six hours) you can wash away most of the Cholesterol and there is nothing to convert. - If you shower or bathe too soon after you sunbathe (like eight hours) you can wash away the \"Vitamin-D lotion\" before it really soaks back into your skin. - It is very easy to get sunburnt without really getting any Vitamin-D in your system at all. So basically most people get little or no value from going out in the sun because they don't do it near-enough noon or they are too clean. The wikipedia page for Vitamin D discusses the particular form of cholesterol and how it all happens and looks like a good place to start if you want to know more.", "Both. In your skin is a substance that reacts with uv light. This converts it into another substances that travels to the liver and is convertee into vitamin D.", "Just to put this out there... For some reason there are people like myself who can't produce Vitamin D and have to take medication. No clue why. I have to take Potassium too. Kidneys and Liver are fine. I'm perplexed and Doctor is perplexed."], "text_urls": [[], [], []], "score": [18, 5, 3]}}, {"q_id": "6hjxe0", "category": "Repost", "title": "What the 2038 problem is.", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["diyw4jk", "diyw6fl"], "text": ["Most computers store dates as the number of seconds that have passed since Jan 1, 1970. They use a 32 bit number to store this. In 2038 that number will overflow, meaning that to many computers, dates will appear to be Jan 19, 2038 one second, and Jan 1, 1970 the next second. This could pose problems, just like Y2K posed problems.", "It's similar to the Y2k bug. Unix systems store dates as the number of seconds that have elapsed since January 1 1970. In 2038, that number (2 billion or so) will exceed the largest number that you can store in a 32-bit unsigned integer. At that point, it will roll over to 0 and systems will think it is 1970 again. Systems are being updated to store this in a 64-bit integer."], "text_urls": [[], []], "score": [4, 3]}}, {"q_id": "6hmff2", "category": "Repost", "title": "How are political parties so evenly split in the US?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dizewaq", "dizex7g", "dizeeas"], "text": ["Because the parties want to win, therefore, they work to make it that way. If an idea becomes unpopular a party will drop it. If an idea becomes extremely popular a party will adopt it or at least make it less of an issue. Let's take gay marriage. [Since 2001 to present more and more people are accepting gay marriage]( URL_0 ). In 2008, Obama was sort of against gay marriage. He said it was a state issue. His party was softly for it though. The reason was the issue was still unpopular. This meant the Democrats could have a bigger tent and include people that were against gay marriage, allowing them to have slightly over half of the vote that year. Now the tables have turned. Gay marriage is a popular issue and the Democrats (including Obama) embrace it as a party platform. And Trump and Republicans? Well, they don't make it an issue. They aren't *against* gay marriage but not for it, allowing them to have people that are for it and against it and were able to get about half of the vote in 2016. So in essence, it's about half and half because the parties are both trying to win, and to win they both need ~51% of the vote. They will change their stances if their stances become unpopular.", "With two parties, the notion is that they would adapt their policies to balance each other. If there were three, they would each be a third. Since it takes 50%+1 to win, both parties are very strongly committed to blocking the rise of a third party. If you're in a party that loses every time, you need to change something. You change an edge policy to get some of the people to vote for you instead of the other team.", "Approximately 42% of voters will always vote Democrat and approximately 42% of voters will always vote Republican. The remaining voters are the \"swing vote.\" Those are the votes who are targeted by ads and choose the direction of the nation at each election."], "text_urls": [["http://www.pewforum.org/2016/05/12/changing-attitudes-on-gay-marriage/"], [], []], "score": [40, 5, 4]}}, {"q_id": "6hmjar", "category": "Repost", "title": "Why do bad smells make us throw up?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dizfmvl", "dizf64f", "dizl89i"], "text": ["In case you ate some of it. It's a biological response to purge toxins from your stomach, if something smells rotten, it probably is rotten and should not have been eaten. now we don't eat such things, but hundreds of thousands of years ago when the response evolved we might have.", "Basically, most things that smell that bad would be very bad to eat. The gag reflex stops us from eating things that could make us sick. Not sure about the exact mechanism", "Smell is our primal indication if something is fit to be eaten or contains too many toxins which would cause us harm prior to consumption. Vomiting is a reflex response to food that the body feels will cause us harm following consumption. The sense and reflex exist for the same purpose. A smell is an aerosol of the source (the smell of pizza is a very small part of the pizza floating through the air) and when it enters the body through the nose the same reflex reaction occurs as if it is in the stomach. TLDR: The body will reject smells the same way it would reject food that is eaten."], "text_urls": [[], [], []], "score": [103, 14, 7]}}, {"q_id": "6hn76c", "category": "Repost", "title": "how does double bouncing on a trampoline work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dizqw6n"], "text": ["When you \"compress\" or add weight to a trampoline, you are adding elastic potential energy to the material since it is bound by springs. If you are by yourself, your weight can only push so much before the tension is too strong for your body weight to keep falling (kind of like when you strap those long elastic bands around your waist and try to run away from its mounting point and you cant go any farther at carnivals), so the potential energy is converted to kinetic and you bounce up. When there are more people and, thus, more weight, when timed correctly one person/weight builds tension on the trampoline and that tension is continued when more weight from a second person is applied. Since you came flying in second while your friend just hit the trampoline, you move it from under his/her feet and they don't have contact anymore to receive the bounce. On the other hand, you gain the potential energy your friend exerted on the trampoline AND the potential energy you exert. The material goes down farther, has more potential, and you go flying into another dimension. TL;DR: More weight results in more energy that can bounce you back up higher"], "text_urls": [[]], "score": [3]}}, {"q_id": "6hp3gv", "category": "Repost", "title": "why you should wait 30 seconds between switching off and on when restarting an internet router", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dj00jf6", "dj0608m", "dj00hth"], "text": ["20 seconds should be long enough. Basically, you need to wait long enough for the capacitors in the device to drain their electricity so that all components that aren't battery-backed completely power down. Otherwise, you may start it back up to find that some bits never actually got restarted.", "I'd like to add an interesting fact to this thread. There's such a thing as a cold-boot attack, which consists of physically gaining access to a locked computer which is running a program, the contents of which you wish to know. The premise is to turn off the computer, quickly remove the RAM cards, and lower their tempurature to prevent the capacitors from discharging quickly. You then load the ram into your own computer, where a specialised program takes the contents of the ram and unloads it to a nonvolatile disk to be read and data harvested at a later time", "Power supplies and routers can carry some leftover voltage in the capacitors that keep things running for a bit even after being unplugged. So it takes a little bit to use up that energy and fully shut down. 30sec is a bit much though, 10sec should be plenty."], "text_urls": [[], [], []], "score": [12, 5, 3]}}, {"q_id": "6hpwz9", "category": "Repost", "title": "If there are thousands of characters in the chinese and japanese language, how do they type on a computer?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dj07s2h", "dj07g0z"], "text": ["I can explain Japanese, which should cover both. They use a QWERTY keyboard, but there are different software keyboards that intercept what you type. So, they type for instance, nerihamigaki. As they type ne the software replaces it with \u306d. Replaces ri with \u308a, and on and on. It would do this with each one until it has written \u306d\u308a\u306f\u307f\u304c\u304dfor them. In Japanese, it starts with this hiragana and then a large list of kanji comes up, with the word you are most likely trying to write as the most recommended conversion:\u7df4\u308a\u6b6f\u78e8\u304d. This word used both kanji and hiragana, but it could do it with only hiragana words, only kanji words, etc. Oh, and the word used here means toothpaste. :)", "For Japanese you type in the hiragana characre(which represent sounds) and then the computer will suggest kanji(characters) based on what sounds you typed"], "text_urls": [[], []], "score": [23, 4]}}, {"q_id": "6hq18w", "category": "Repost", "title": "Why are cologne commercials abstract and nonsensical?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dj08lfq", "dj0adhh", "dj0jyq9", "dj08gak"], "text": ["they're advertizing something that cant actually be conveyed electronically yet (maybe smell-TV will happen someday), so their choices are limited to metaphors and abstractions or \"trust me dude, it makes you smell nice\"", "You can't convey a smell visually, also high end perfumes are a lifstyle brand/luxury good. The commercials convey an aspirational or class level attitude.", "Did you ask this question after watching that Jared Leto cologne commercial? Haha", "I don't watch cologne commercials but I'm pretty sure old spice does it simply to be memorable. and it works, at least for me, because that's the only brand I know of that does this."], "text_urls": [[], [], [], []], "score": [11, 5, 3, 3]}}, {"q_id": "6hq79l", "category": "Repost", "title": "How are old movies that looked crappy on screen now being sold in HD?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dj09r82"], "text": ["As I understand it; - Old films were filmed using Film (funny, it's in the name): Film being an extremely high resolution (but it varies with different grades and types of film etc). - Those old films were originally digitized onto tapes etc for broadcast on a standard composite signal (CVBS), for TV and Tape. So its resolution/quality became limited by that medium. - By returning to the actual Film, and re-digitizing to today's standards (as the information/quality is actually there for a higher resolution within the film itself) a higher quality of the film can be produced and released. There are all sorts of caveats to this process, including the lossy nature of film (it degrades over time, and it costs a pretty penny to keep these stored in the appropriate manner for these studios) as well as losses in the process, etc. A lot of digital 'fixing' has to be done. I think this process is called re-mastering."], "text_urls": [[]], "score": [4]}}, {"q_id": "6hqho6", "category": "Repost", "title": "Why is gold valuable? Also, why was gold important to ancient civilizations?", "title_urls": {"url": []}, "selftext": "I know it has good conduction properties and doesn't deteriorate, but there are other similar elements. Why was it important for ancient civilizations, especially ones that didn't use currency?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dj0cbrb", "dj0c9vh"], "text": ["It's shiny, doesn't oxidize, yellow is rather unique as metallic color. It's also relatively soft and malleable with a low melting point (for a metal) that makes it a pretty nice material to work with and create art/religious symbols and being not that common makes it special, too.", "For one, it looks pretty good. Most metals, if I'm not too mistaken, either look gray - in various shades, but ultimately gray - or reddish, like copper. Gold looks...well, gold. It's somewhat unique in that regard, as far as metals that won't harm you go. Two, \"doesn't deteriorate\" doesn't even begin to describe gold. Gold is incredibly durable after being amalgamated with relatively small amounts of other metal (such as silver), with the raw form being quite malleable, but when amalgamated, it'll outlast pretty much anything. This made it incredibly valuable as a method of storing value (what we call currency) and showing off wealth, at the same time. I think this answers the \"civilisations which did not use currency\" bit - even if you do not use currency, as in coinage or other methods, you will most likely need to store the value of otherwise perishable goods. Gold is one of the most un-perishable good you'll ever find. It's by no means a complete explanation, and I hope more knowledgeable people will elaborate further and correct errors I've made."], "text_urls": [[], []], "score": [13, 6]}}, {"q_id": "6hr8gd", "category": "Repost", "title": "Why can't you measure position and velocity at the same time?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dj0itbx", "dj0l5y1", "dj0obrc", "dj0o1vq"], "text": ["Are you asking about the [uncertainty principle]( URL_0 )? This is only relevant for particle position and velocity. Everyday objects can easily have their position and velocity measured, since the margin of error that's acceptable for these objects is going to fall within the uncertainty limit.", "This only applies to subatomic particles. The most common way to observe something is by looking at it. This boils down to bouncing photons (the particles of light) off of an object, and into your eye. For ELI5's sake, let's imagine that the subatomic particle you're observing is relatively the size of a beachball. The problem is, the particle is so small that bouncing a photon (or electron) off of it is like throwing a volleyball at it. When it bounces off, it's going to cause the beachball to move, even if just a little bit. Because of this, there is no way of observing without affecting its position.", "Imagine you're looking for a ping pong ball endlessly bouncing around a dark room. You can feel around for it and find its exact position, but as you feel around for it, you'll hit it and change it's velocity. You could also stay quiet and listen for the sound it makes when hitting a wall to measure it's velocity, but that only gives you a rough idea about position. It's sort of like that; the act of measuring one changes the other.", "A free particle travels as a wave of probability. The wave of probality is a [wavepacket]( URL_0 ) structure. To create a wavepacket requires adding different wavelengths together to form a location spike. The wavelength is related to momentum. When the wave packet collapses the particle has a position and momentum based on the wave probability. To make the wave packet more confined(high location certainty) requires adding a greater range (uncertain momentum) of wavelengths. The opposite is true too, fewer range of wavelengths means the wavepacket spreads out."], "text_urls": [["https://en.wikipedia.org/wiki/Uncertainty_principle"], [], [], ["https://www.advaitainfo.com/imagen/curso/incertidumbre1.gif"]], "score": [11, 7, 4, 3]}}, {"q_id": "6hrlhq", "category": "Repost", "title": "Why do we open our mouth / stick tongue out when doing work that requires precision like threading a needle?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dj0nckk"], "text": ["There's a few theories on this, to even include one adopted from your infant stage. However, the one I agree with most is: Biting the tongue or opening your mouth locks down or relaxes motor functions in the head, giving your brain less diverted resources to concentrate on precision. This follows to your body going still and rigid except for the necessary appendages. For instance, when you're threading a needle as you mentioned, you move slower, sometimes even slightly jerky, without the rest of your body moving at all. Your brain has not only turned all of its attention to the task at hand, but it's trying to balance that with providing only a minimum amount of energy for the delicate task. This would also explain why many people need quiet at times like this, because your brain would prefer no outside distractions, as it has to divert energy to process the sounds."], "text_urls": [[]], "score": [3]}}, {"q_id": "6hrls6", "category": "Repost", "title": "Why can't we write Braille like the regular alphabets?", "title_urls": {"url": []}, "selftext": "Why can't Braille dots be arranged in the shapes of regular alphabets? What difference does it make to have weird shapes representing every alphabet?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dj0lxpi", "dj0m93x", "dj0rd14"], "text": ["Imagine trying to read the word \"Ill\" (other word for sick) in Braille. Not easy. Other characters that are easy to confuse: E and F, O and Q, X and K, U and V. The Braille alphabet is designed to avoid these confusions.", "Find an old typewriter and some tracing paper in it. Remove the ink ribbon and put \"AA\" next to \"M\" or \"VV\" next to \"W\" or try to tell the difference between a \"Q\" and an \"O\" once someone has rubbed it a few times. Another reason is space. To do what you're suggesting takes 3-4 times the room it already does, which takes about twice the room regular fonts do.", "The braille dots can be so arranged, but then that would be using a writing system designed for eyes, but by using fingers instead of eyes. It would be using the wrong tool for the job. The alphabet is optimized for reading with eyes and loses its advantages when read by finger. Therefore it's better to use a system that is designed for the fingers, even if it's difficult to read with the eyes."], "text_urls": [[], [], []], "score": [33, 13, 5]}}, {"q_id": "6hrtf7", "category": "Repost", "title": "Why does it take forever for my phone to load a GIF when it can immediately play a higher quality video with sound?", "title_urls": {"url": []}, "selftext": "This happens for me regardless if I'm connected to wifi or using data.", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dj0ou96", "dj0p4fi", "dj0qvkd", "dj0ps36", "dj0ox5p"], "text": ["From my understanding it is because videos are compressed and GIFs are not. GIFs are literally just a whole lot of pictures that flash up sequentially, but if you look at each one individually you'll notice that large parts of each picture don't actually change from picture to picture (i.e. the background might be the same throughout). So a compressed video file recognises this and tells your video player that those parts don't need to change and so the amount of \"new\" information from frame to frame isn't anywhere near as much as in a GIF which treats every frame as entirely new information. Another way to look at it is through animation. If you make a crude animation on a flip book you have to draw everything on each single page and so there is a lot of information in your flip book. However hand drawn animation will use static backgrounds and you only need to redraw what is actually moving in the scene on each page (in this case your pages would need to be translucent so the background remains visible). For example in a shot from the Simpsons the couch may not move and so it is a static background so the animators just need to draw Homer's movements on a clear sheet and \"flip\" through them over the top of the static couch and background. At least that's how I understand it, someone with a much better understanding may be able to add to this and/or describe it more succinctly.", "GIF is an ancient, and not very good format. Why it is still alive is a mystery to me. It was never designed to be used over network connections, which vary in speed and bandwidth. Modern video formats, like used by Youtube, are explicitly designed to start playing as quickly as possible.", "GIF animation is optimised for cartoony animations in which many of the pixels (e.g. a white background) don't change. Because in photo-quality videos almost every pixel changes on every frame, the size balloons compared to, for example, an MPEG-video which is optimised for photo-quality imagery that changes more gradually.", "Variety of reasons. The most important is that GIF lacks the more modern compression tech in video codecs, so it is a much larger file / takes a lot more bandwidth. It also doesn't have the hardware playback assistance that video codecs do, so it requires more CPU cycles (and battery, for mobile devices) to play back. That's actually why imgur started automatically converting gif files to mp4 video, several years ago: URL_0", "Online videos are encoded at several \"bit rates\" (quality settings), and the video player is usually capable of switching between different bit rates on the fly. It starts with a low bit rate and tests the connection to see if it can switch up to better quality file. GIFs are encoded in a very simple way, one of the effects of this is that they are encoded at a constant, much higher \"bit rate\". It takes much longer to buffer enough frames to start the animation, and if the connection is slow, the browser just stops playing the gif to buffer again rather than switching down to a lower quality."], "text_urls": [[], [], [], ["http://blog.imgur.com/2014/10/09/introducing-gifv/"], []], "score": [39, 6, 4, 3, 3]}}, {"q_id": "6hs0za", "category": "Repost", "title": "Why does helium make your voice high?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dj0p9i1", "dj0p53j"], "text": ["Your voice begins in your voice box, which scientists call the larynx. Your larynx contains your vocal cords. These two folded mucous membranes vibrate when air passes between them. These vibrations resonate throughout your throat, nasal passages, mouth, tongue, and lips to create the sounds you make when you speak. The air you breathe is made up mainly of nitrogen and oxygen. Helium is much less dense than regular air. That's why helium is used in balloons to make them float. Due to its lower density, sound travels over twice as fast through helium than it does regular air. When you breathe in helium, your voice travels much more quickly across your vocal cords. This results in the funny sounds you make when you talk after breathing helium. Some people think that the helium changes the pitch of your voice. In reality, however, your vocal cords vibrate at the same frequency. The helium actually affects the sound quality of your voice (its tone or timbre) by allowing sound to travel faster and thus change the resonances of your vocal tract by making it more responsive to high-frequency sounds. SOURCE: URL_0", "From what I learnt, helium is less dense than air. So when you speak, the rate of helium going through you voice cord is higher than normal producing more vibration. More vibration mean higher frequency."], "text_urls": [["http://wonderopolis.org/wonder/why-does-helium-change-the-sound-of-your-voice"], []], "score": [8, 3]}}, {"q_id": "6htsu7", "category": "Repost", "title": "How can the USS Fitzgerald hit another huge vessel?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dj1199c", "dj11j8v"], "text": ["It's not a question of seeing each other so much as having the time to maneuver. Large ships don't really turn or stop on a dime. Sometimes there's a space issue as well if the water is shallow.", "There will no doubt be an investigation to figure out what exactly happened. Like most similar incidents it will probably end up with blame for many people to go around and with the knowledge that lots of different things went wrong at once. Keep in mind that while these ships especially the container ship are really big and hard to overlook, they are also not very maneuverable. Ships don't really have anything like breaks the can only decelerate and make turns rather slowly compared to land vehicles. Especially the container ship is very far from nimble. Chances are that quite a few people really did screw up big time, but what exactly happened is going to take some time to figure out. To get a general idea of how such collisions can happen in general and not this specific case you might want to watch this old navy training video about the USS Frank E. Evans which got into the way of an Australian aircraft carrier. [I Relieve you Sir]( URL_0 )"], "text_urls": [[], ["https://youtu.be/zPv-4wIw_rI"]], "score": [3, 3]}}, {"q_id": "6hum5p", "category": "Repost", "title": "Why is the 1-2-3 on the top row of a phone keypad but on the bottom row of a calculator?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dj17zpd"], "text": ["the first phones with an actual keypad used it to match the old rotary phones, which had the lowest number first. calculators existed before that, and had already established the 7-8-9 on the top row"], "text_urls": [[]], "score": [3]}}, {"q_id": "6huzxz", "category": "Repost", "title": "Why do companies and sellers always blur license plates? What am I going to do with that information?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dj1csjj", "dj1aswf"], "text": ["1. Seeing a license plate is very different from recording and publishing when and where it was. Enough photos and we could piece together the majority of people's lives allowing for burglars, stalkers, rapists, exes, even government to destroy someone's life. 1. There are people who will find license plates of cars with the same make and models as theirs from a different state, clone their license plate and then use the vehicle in criminal activity. More often than not, it is simple stuff that will never make it to the owner like parking violations, but sometimes it is more serious stuff. Not only does this unfairly put the owner in question, but it makes it significantly harder to catch the offender. 1. Common decency. Broadcasting anyone's personal information without their permission has long been reprehensible because you have no idea the unintended consequences that could follow. 1. Your own protection. STORY TIME! Recently there was a young man who decided to harass my eldest son. He made fake online identities, bought VOIP numbers, all the clever things that someone would do in order to evade identification. HOWEVER, he sent one photo from his work that had 3 license plates in the background and a Wendy's sign off in the distance. From that information, I was able to find his town and exact location he took the photo from. I found his name, his address, his parent's names, their phone numbers, his pastor's name and phone number and with enough digging that he was soliciting and distributing nude photos of underage girls. I don't even have access to any government resources and was able to do this. Imagine what the government can do! Now, I doubt you are distributing child pornography, but unless you implicitly trust the government, and everyone else who has internet skills, don't post license plate info. If you ever have another question about why to not post personal information, just ask your local H\u0336a\u0336c\u0336k\u0336e\u0336r IT specialist.", "A license plate is known as personal info like passwords, you can get sued if you shared that information online without their permission. That is why they usually block it or blur it out"], "text_urls": [[], []], "score": [13, 3]}}, {"q_id": "6hv0ad", "category": "Repost", "title": "How can a massive container ship collide with a giant navy destroyer in open water?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dj1b1gf", "dj1bti3"], "text": ["A lot of people are asking that question currently. We do not know what happened. Remember that big container ships are designed to do long straight hauls and therefore have problems adjusting their speed or turning. When they get close to shore they get tugboats to help them but out at sea you need to just stay away from them as they have no way to avoid a collision. And the area involved here are one of the biggest shipping lanes in the world with several big container ships passing you. So if you want to cross the shipping lane you need to be very aware of all the other ships and time the crossing to be between two ships. We do not know what the circumstances was in this case. It may have been low viability, there may have been inexperienced or tired crew, they may have turned off their lantern and radar to operate stealthy as a navy destroyer might do in combat or exercise. The answer will come as more information is being uncovered.", "[This comment]( URL_0 ) from a similar question gives the answer. In short: while their are rules, when maneuvering a huge heavy ship, a small error can be very hard to correct. > It's not so different from walking toward someone on the sidewalk where you both move left, then both move right\u2014just in very slow motion, and with a louder crunch when you bump together."], "text_urls": [[], ["https://www.reddit.com/r/explainlikeimfive/comments/6hr7yn/eli5_how_does_a_ship_run_into_a_ship_in_this_day/dj0iqmd/"]], "score": [8, 4]}}, {"q_id": "6hvhjx", "category": "Repost", "title": "How does a 550 ft. Navy destroyer run into a merchant ship 2x it's size? How many mistakes go into such an accident?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dj1fae8"], "text": ["I assume you're talking about the USS Fitzgerald. She is actually 505ft, just a note. I don't know what kind of tech is on the ships, but it did happen in the dead of night, where lookouts are less useful. The ships definitely both have radar though, and at least one of them should have executed evasive maneuvers. That said, radar isn't always perfect. If you've ever seen a real life radar screen, it's a clusterfuck in busy waters. Clouds show up, too. There are measures to remove them, but they aren't perfect No matter how disciplined a sailor is, they are still human. At night, it's dark and serotonin is released into the brain, reducing awareness. You can't light a bridge because then you won't be able to see outside, and your natural night vision will be shot. Based on the damage, it looks like ACX Crystal was trying to overtake the USS Fitzgerald on the starboard side, but there was a miscalculation in the course. If both ships followed the proper procedures for collision regulation, this is the only case I can think of that would result in that damage. Could be either helmsman's fault, or a radar operator. Ships take a long ass time to alter course. It's very possible someone noticed minutes in advance, but the ships were not maneuverable enough to make the necessary adjustments. It could have been a wrong order or a wrong report. I know of one case where a lookout reported a container vessel on the starboard side, but it was actually on the port side, so when the ship altered course to port, under the officer's command, the container vessel plowed into it. This is like a fifth hand story, so the details are fuzzy, but that's the gist of it."], "text_urls": [[]], "score": [3]}}, {"q_id": "6hy7b9", "category": "Repost", "title": "How does a U.S. Destroyer, a vessel equiped with advanced technological systems, that is supposed to engage in tactical naval warfare, collide with a cargo ship?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dj23u5r", "dj23nza"], "text": ["Massive and systemic watch-keeping failure on the part of the Naval Vessel's crew. Heads are going to roll here. Court-martials, possibly criminal-negligence charges. There is no excuse for this. None. Navy Ships have multiple people in the pilot house, lookouts all over the ship, people in CIC monitoring surface contacts. State of the art computer processors crunching enough data to take down 10's of targets at mach speeds. Able to scan the environment with different radar systems. The Cargo ship had the right of way : > *Collision Regulations Rule 15: When two power-driven vessels are crossing, the vessel which has the other on the starboard side must give way and avoid crossing ahead of her.* Navy ships also are required to have other vessels standoff outside their respective exclusion zones, to avoid [shit like this]( URL_0 ) happening. It's a complete breakdown of every single navigational procedure.", "I don't know if it's relevant this time, but a little over 16 years ago, the US Navy proved that distractions can cause disasters. In early 2001, a Los Angeles-class submarine conducted an emergency surfacing maneuver ... directly underneath a Japanese fishing boat. The ship sank, and 9 people onboard died, including 4 high school students. Courtesy the US Navy's \"Distinguished Visitor Embarkation\" program, [the $2.1 billion fast attack submarine was under the control of an oil company CEO and a freelance sports writer for the maneuver, as directed by the ship's captain.]( URL_0 ) EDIT: If you don't have a picture in your head of a sub surfacing in an emergency, [it looks like this]( URL_1 ). Imagine that submarine coming up directly underneath a boat and you have the right idea. Anyway, if something crazy like that can happen once, perhaps it can happen again..."], "text_urls": [["https://en.wikipedia.org/wiki/File:INTEL-COGNITIVE-Cole.jpg"], ["https://en.wikipedia.org/wiki/Ehime_Maru_and_USS_Greeneville_collision", "https://www.youtube.com/watch?v=eOqalX5FJ2c"]], "score": [4, 3]}}, {"q_id": "6hysyw", "category": "Repost", "title": "what exactly is radiation?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dj26ftr"], "text": ["Radiation is a broad term and the name stems from something seemingly invisible that affects something at a distance. If you're thinking of that scary stuff that gives you cancer, you're thinking of *ionizing radiation*. That is, radiation that is energetic enough to knock away electrons of molecules and atoms. This radiation can therefore destroy your DNA which can lead to nasty mutations and cancer. There are many types of ionizing radiation, and a distinction between directly and non-directly ionizing radiation is made. But it's all particles (protons, neutrons, electrons, photons, even small nuclei, you name it!) with enough energy to knock out electrons."], "text_urls": [[]], "score": [4]}}, {"q_id": "6i02dn", "category": "Repost", "title": "Why/how does total sleep deprivation lead to death?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dj2g18g", "dj2heqt"], "text": ["There are many reasons. Sleep is important for the leveling of hormones. If one isn't allowed to sleep that regulation starts getting very screwed up. Which is bad Sleep gets rid of cortisol in the brain. Which is the stress neurotransmitter. If that is never removed the stress will cause increased heart rate. Increased blood pressure and then death. Along with a host of other things that the body does more efficiently whilst asleep and if it can't do those things then things get out of balance", "Sleep allows your brain to flush out harmful chemicals that build up throughout the day. You don't want these to continue to build up. Not sure if they will kill you by themselves, but they will cause neurological problems, and couple that with the other changes your body goes through, you're not in a good spot. After a couple days of no sleep, you don't process glucose properly. Glucose is quick energy for your body. If you can't get enough glucose through eating, or if your body can't use the glucose (which is what diabetes does), your body will use other sources. It will burn fat, but too much fat burning can be toxic. Fat burning produces an acid called ketones, and a high amount of ketones can kill you. If you've ever heard of someone with flu-like symptoms going to the hospital and nearly dying or even dying because they were an undiagnosed diabetic, it's because they had severe diabetic ketoacidosis. Mild to severe ketoacidosis can happen in non-diabetics if their bodies burn too much fat over a period of time. Should you survive the fat burning, the next thing to go is protein. Your muscles are made of proteins, and your body doesn't particularly care which muscles it gets that protein from. Coming from skeletal muscles will make you weak, perhaps unable to do daily tasks. Coming from your heart? That's just plain dangerous. I'm not actually sure if your body stops processing glucose completely or if it's just extremely difficult, but many sleep-deprived people crave glucose. If your body can process glucose, but not very well, you will need to eat a lot of sugary/carbohydrate heavy foods to prevent fat and muscle burning. If you can't get it, then the bad things above happen. Your immune system also stops working as well as it should. I'm not sure if this just means you get sick more easily and have a harder time fighting off illness once you are sick, or if it can become so severe that you can actually die from a mild illness. And then your body temperature drops as well. It may be able to decrease to the point that it's no longer compatible life. Stress hormones like cortisol builds up throughout this process, from the beginning, and they can put more strain on your body. If none of these things by themselves kill you, you are still in pretty rough shape. We know the ketoacidosis can kill you by itself, and cannibalizing heart muscle is a terrible idea. But those can maybe be avoided. The combination of all these things may be enough to kill you. There are some arguments about whether a human has actually died from from sleep deprivation itself. That may be because the people studying it assign another cause listed above as primary cause of death, not the sleep deprivation itself. If you want to learn about how bad it can be, check out [fatal familial insomnia]( URL_0 ). Apparently, some people can last 18 months without adequate or any sleep."], "text_urls": [[], ["https://en.wikipedia.org/wiki/Fatal_familial_insomnia"]], "score": [21, 3]}}, {"q_id": "6i1ua3", "category": "Repost", "title": "Why do humans need a large variety of different food types to receive all the essential nutrients, while other animals can seemingly do so off of relatively few different types of food?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dj2uf72"], "text": ["You don't *have* to eat a large variety of foods. You just expect a very high quality of life."], "text_urls": [[]], "score": [3]}}, {"q_id": "6i3gxf", "category": "Repost", "title": "Why does unplugging things like a computer or internet router and then plugging them back in, generally resolves most issues you may have had?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dj37os8"], "text": ["Many of such issues are machines metaphorically \"getting lost\". A computer or a router ended up in some state that was unexpected or poorly handled by developers, and there is no obvious, easy or possible way back out of it. Turning it off and on again is essentially getting it back to the starting point (which is why it's called \"reset\" or \"reboot\"). Since the thing is merely lost instead of being broken, it would then continue to work as it is supposed to."], "text_urls": [[]], "score": [3]}}, {"q_id": "6i3prd", "category": "Repost", "title": "How are coding programs coded?", "title_urls": {"url": []}, "selftext": "I'm currently self-learning how to code / program (Python) - but how are these different systems programmed in the first place?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dj39r6u", "dj3cy3f", "dj3t0hc", "dj39vdv"], "text": ["They use another programming language to code up that one. And they use another language to make *that* one. And it goes on further and further back, until at some point they're writing the first text based programming language by putting punch cards in a machine. But what reads the punch cards? Go further back and they're programming by flipping switches on a big room sized box. And what reads those switches? Go further back, and they've **hard coded** the programming language directly into the computer's construction, like, the specific connections between the vacuum tubes are the programming language. This, of course, a very, very simple programming language.", "Today they would be mostly created in another programming language. C in particular is a starting point since it was designed specifically to be easy to impliment on a new platform. So how is C (or another language) created without using an existing compiler? By determining the assembly instructions (instructions specific to one type of CPU) that would that comprise it on paper, converting each of those instructions into the binary values used by the CPU (machine instructions) and then finally creating some kind of input with that data, for example cutting punch cards or fabricating a ROM chip. For example a C compiler might have a line that simply reads `i++`, meaning it increments a variable I call `i` by 1. If I wanted to convert that into assembly code for say a 6502 (a popular 8 bit CPU that was used in everything from the Apple II to the Nintendo Entertainment System) I can write `INC $05`, which is a convenient and fast instruction that will load the value on page 0, offset 5 of memory (the 6502 can access 256 pages of 256 bytes each for a total of 64KB), add 1 to that value and then save it all in just 5 cycles. On other types of CPU we would often have to use 3 seperate assembly instructions to load, increment and save the value so the 6502 is a real time saver here. Finally we want to convert that assembly instruction (that still looks sort of like english) into actual machine instructions that can be used by a 6502. There are actually 4 different INC instructions, depending on how we want to address memory. The one we used, where it didn't specify a page and instead implied the zero page, is instruction `$E6` (or 230 in decimal). This instruction requires 1 additional byte to be complete, the address offset which was `$05`. This means our line of code translates into machine code as the sequence `$E6 $05` (or `230 5` in decimal). Finally we want to put this into a computer somehow so we take a metal tool and punch out the appropriate holes (1110 0110 0000 0101) on a punchcard which is then fed into a computer. Creating computer programs in assembly code or machine code used to be very common. One of the most well known software companies on the planet, Microsoft, got started because its founders Bill Gates and Paul Allen where very good at hand writing extremely efficient programs like this in order to work on the very limit memory of early home computers. Microsoft's first major sale was a BASIC interpreter for the Altair 8800 (a computer they had never actually touched, they developed their program purely from the Altair specifications) and while Paul Allen was flying to MITS to demonstrate it for the first time he realized they hadn't written a bootloader (a small program used to get the machine started and load the program you wanted, in this case their BASIC interpreter). So on his tray table he wrote, translated into binary and then punched a program tape for the bootloader, all without a computer (laptops wouldn't exist for decades). It ran on the first time. To give you an idea what a program tape looks like, [here]( URL_0 ) is one copy of that BASIC interpreter, preserved at the Computer History Museum.", "Modern compiler developers often use a process called 'bootstrapping' to allow the compiler to be writen in it's own language. For example, if you've designed a new language, let's call it 'Look', and you want to write a compiler for Look, then you can of course write that compiler in another language (C is a popular choice), but often it would be easier if the compiler was written in Look, because there may be usefull paradigms included in Look that are hard to emulate in C. In addition to that, if the Look compiler was written in Look, then any improvements you make to Look will also improve the compiler. Finally, it means that you only need to be an expert in Look to write a good Look compiler, instead of having to be an expert in both Look and C. Enter Bootstrapping. The idea here is that you write extremely minimal and simple compiler for a subset of Look (protoLook) in a different language (or in extreme cases you can even write the bytecode by hand). ProtoLook is too simple to be of much use for actual work (it would be too tedious since many commands are missing), but it is a complete language in the sense that you can write anything in protoLook, given enough time. Now that you can compile protoLook, you can write a compiler for protoLook in protoLook. At this point you don't need the other language any more, everything can be done in protoLook. Now that you have a running protoLook compiler, you can start adding extra features to the protoLook compiler. With every feature you add, protoLook gets a step closer to Look, and with every feature you add you extend the capabilities of the protoLook compiler which makes it easier and faster to add new, more complex features. Eventually you've added all the features you need and you end up with a full-fleged Look compiler written in Look. The language is bootstrapped.", "You have to clarify your question a bit. If I understand you question, I think you mean, how does the programming language itself get programmed? Assuming that is what you're asking, I'll answer that. Basically it is programmed from another language, in this case it started being programmed using c, which is just another language. Before all of that even, you need to understand that computers are communicating using 1s and 0s. In the beginning we used punch cards with literal holes in them to represent 0s and 1s. Then we got assembly language where we decided we could call 101000 to jump to another command. And we shortened it to jmp, so now we could jump to another part of the program without remembering the long string of zeros. Later on, we got even more advanced, and we used that assembly language to program another language, where we could write short programs without worrying about that jump command. Now we have a language where we can use if statements, like if the temperature is less than 50, start the heater. Now we don't need to worry about the jump command at all. Essentially, we don't write many programs in assembly anymore. And even c, sometimes we replace with ones like python where it is easier to do things. But, keep in mind, making it easier to program, means you lose flexibility. So, if you wanted to do something that language doesn't support, you're SOL. Hope this helps."], "text_urls": [[], ["http://www.computerhistory.org/collections/catalog/102622400"], [], []], "score": [68, 40, 5, 3]}}, {"q_id": "6i440m", "category": "Repost", "title": "How does 'mining' for cryptocurrencies work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dj3ef7o"], "text": ["Say you are working for a bank. You also have a savings account for in that bank. The bank hired you to keep track of what the bank is doing. So you do your job, record that Harry paid Sally $20, etc. You show your work to the other workers at the bank. The other workers at the bank check to see if you did your job well, you check the other workers at the bank. In exchange for your work, the bank adds money to your account. This is exactly how Bitcoin mining works. The \"mining\" process is administration work on keeping track of the transactions of Bitcoins. When other people in the network check your work, they agree that work has been done and award you more Bitcoin."], "text_urls": [[]], "score": [3]}}, {"q_id": "6i5g51", "category": "Repost", "title": "Why is tipping a prevalent practice?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dj3mos6"], "text": ["American style tipping is a relic of the end of slavery. The wave of completely uneducated and largely unskilled former slaves that left the plantations as soon as they were able to did not immediately find work. Many of them subsisted on what little they could get by working for free in places that \"allowed\" them to beg for a tip after they had lifted and carried for the customer."], "text_urls": [[]], "score": [3]}}, {"q_id": "6i7mfl", "category": "Repost", "title": "Why is fathers day celebrated on the same day in US/UK, but mother's day isn't?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dj42p0x"], "text": ["The UK combined a religious holiday, \"Mothering Sunday\" that was part of Lent, where you would traditionally return to the church you grew up in (your mother church) with the holiday celebrating your mother. The US, being more protestant and not as tied to the liturgical calendar as Anglicans and Catholics does not heavily practice the traditions of Lent and did/does not practice \"Mothering Sunday\" much at all. So when the US was choosing a time on the calendar to set the holiday celebrating mothers they chose to not put it during the Easter celebrations and so moved it to a relatively quiet point after that."], "text_urls": [[]], "score": [5]}}, {"q_id": "6i9r3g", "category": "Repost", "title": "Why are witnesses swearing an oath in court if they're gonna lie anyway?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dj4jzx3"], "text": ["Legally, lying under oath is called perjury and it's a separate crime. If you purposefully give false testimony after swearing an oath you can be charged with perjury. Realistically, that almost never happens. One reason is that courts often can't be sure who is lying and trying to figure it out with certainty is nearly impossible. It's even harder to know whether a witness was actually lying or honestly mistaken. Another reason is that it's already hard enough to get people to come to court to testify. Most people don't want to do it and if they think there's a good chance they'll get charged with perjury for testifying, they'll try to avoid it even more. Courts also want lawyers to focus on the facts of the case and don't want them to spend a bunch of time trying to get the opposing party thrown in jail for telling a lie. The oath is still useful, though, because it marks your official testimony that you can't take back once said. If you say something when you're not under oath, you can always take it back and claim you were \"just kidding.\" If you testify under oath, you're stuck with what you said. tl;dr - The oath is useful to let the Court and witnesses know that testimony given under oath is official and can't be taken back. The state can also charge someone with perjury for lying under oath in extreme cases."], "text_urls": [[]], "score": [6]}}, {"q_id": "6id901", "category": "Repost", "title": "What's involved in remastering a film, song or game, and how does it work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dj5ayqz", "dj5bhne"], "text": ["In music it means the original audio tapes (aka masters) were used during the production process. Because of advances in audio playback, noise reduction, mixing technology and digital conversion the results are generally superior to previous releases. This differs from a normal rerelease which simply uses an existing final mix (which can be decades old) to create the new release.", "In games it can mean anything from simply rendering at a higher definition to give smoother lines to a complete revamp by adding new textures, remapping controls, and changing the lighting."], "text_urls": [[], []], "score": [5, 3]}}, {"q_id": "6idfa5", "category": "Repost", "title": "Why does the washing machine always say it's 1 minute left, but leave me hanging for at least 10 minutes?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dj5c3wp"], "text": ["The timer is the optimum time for that particular wash, but there are a couple of instances that can throw off the timer. * Filling with water. When the washing machine is initially filling, it will admit some water, and then tumble slowly, stop, put water in, tumble slowly and so on. What it's waiting for is a fill level sensor inside the washing machine to register that the water is at a particular level. If you've put a big load into the machine, or a very absorbent load, such as towels, the clothes will soak up more of this water, and it'll have to go through more fill/tumble/fill cycles before this level is registered. And of course the flow rate of your water supply will have an impact. * Balancing Most modern washing machines have a bit of cleverness in them to try and prevent an out of balance load going crazy and shaking the machine to hell on high spin. They'll gradually spin the drum up, and monitor how out of balance the drum is, using [various methods]( URL_0 ) such as measuring the movement of the drum, or how much power the motor is using, or how the speed of the drum is changing (if it's out of balance, the drum will be going slow/fast/slow/fast/slow, as the heavy bit starts the uphill part of the rotation). If the machine detects this, it'll stop the spin, then slowly tumble the washing again in an attempt to redistribute it. It will keep doing this until it spins more smoothly, and then start ramping the speed up. Until it gets to that point, the timer is (effectively) getting no lower, because it's making no progress. Yet on every machine I've seen with a timer, the timer will keep counting down even if it's taking time balancing the load. * Spinning Some washing machines can detect the water coming out of clothes, so will know when the clothes are spun as dry as they can be. Naturally depending on the load, this will take varying times. In my experience by far the biggest factor that affects the timing will normally be the machine balancing the load though. This can take a long time for the machine to get right, and sometimes it'll never manage it, which is why occasionally if you had a big, heavy load, it'll sometimes appear to be a completed cycle, but the clothes will still be soaking wet. This is where the isolated spin program comes in handy. This is why you end up with varying times. The counter will count down whether or not the machine is making progress or is in one of the 'wait' periods like filling the machine, or balancing the load prior to spinning, and when it gets down to 1 minute, it'll sit there until the machine actually is finished. They use this logic because they, generally correctly, assume that most people won't time it down to the exact minute and will just come back sometime near when it's supposed to finish, so most won't encounter this quirk of behaviour."], "text_urls": [["http://archives.sensorsmag.com/articles/0803/34/main.shtml"]], "score": [15]}}, {"q_id": "6ik98i", "category": "Repost", "title": "If monopolies are illegal in the US as per antitrust laws, how come there are cities that reportedly only have one ISP to choose from?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dj6xj5z", "dj78g71", "dj75hsk"], "text": ["Not all monopolies are illegal. For example, some industries have natural monopolies. This is actually very relevant to your question about Internet Service Providers. A natural monopoly essentially develops when startup costs or other barriers to entry in the industry (such as complex regulation) naturally make it very difficult or impossible for another company to enter the market and compete with the existing market player. It's not necessarily the case that the existing market player is trying to smother all competition, in some cases it is simply too expensive or too risky for others to enter the market and be profitable. It's extremely costly, complex, and time-consuming for a new ISP to enter the market or even for an existing ISP to expand to a new service area. It requires the ISP to deploy their own infrastructure\u2014literally install cabling that goes directly to each individual customer's home (often costing hundreds of dollars per home). In many cases this may involve digging trenches (including through people's yards) as well as digging up sidewalks, digging up roads, working with local governments to gain access to easements, access to underground conduits or sewer/drain systems, access to telephone poles, etc. This is all extremely costly, time-consuming, and complex. There are also a lot of regulatory compliance issues to deal with as well. Unless you have billions of dollars in funding, it just isn't feasible to deploy a new network and lay new cabling to people's homes. It is possible in many cases for ISPs to receive government subsidies to help pay for some of the cost of deploying a new network or expanding service areas, but it's still not enough. You still need major investors or enormous capital to lay new cable. Ultimately, if it isn't profitable for another ISP to service a given area, they won't bother trying to a lay cable and deploy a new network there. The ISP also has to consider\u2014how many people will actually switch over to our ISP if we service a given area? ... Can you imagine spending hundreds of dollars installing cabling to a home and then that home never subscribes to your ISP? That's a total loss and really makes it difficult to earn a return on your investment unless you're sure that your ISP is going to be able to break through the market and incentivize a ton of people to switch over. What some smaller ISPs have done to mitigate this problem is that they only bring fiber-to-the-curb (FTTC) or fiber-to-the-neighborhood (FTTN) and then they make subscribers pay an initial connection fee of like $300 or whatever to help pay for the cost of wiring fiber directly to their home. But obviously this makes it a lot more difficult to get customers to sign-up for your service and isn't necessarily going to make your service profitable. All it does it make sure that you only spend the time/money wiring up homes that have people who are committed to subscribing to your service. It's also worth noting that there has been some past controversy regarding and municipal broadband competition. Some towns/cities with natural ISP monopolies have proposed building municipally-sponsored broadband networks that would bring high-bandwidth internet connectivity to the home, usually at a competitive price. Many ISPs have lobbied against these proposals and blocked these types of municipal broadband projects from going ahead because essentially they are arguing that these local governments are abusing their government power/authority by interfering with the free market and giving the municipal broadband projects unfair access/funding/subsidies or other advantages which the existing ISP monopoly doesn't get to benefit from. ISPs have successfully stopped many of these projects from going ahead, but it's also worth noting that most of the same ISPs that are complaining receive enormous amounts of funding/subsidies from government(s) to help build out their own networks. TL;DR: It's usually not impossible for other ISPs to enter the market and compete... It's just that it's often very risky, time consuming, and prohibitively expensive to deploy new network infrastructure and lay new cable. The risk is often greater than the potential reward and in many cases it could take several years to become profitable even if the ISP manages to secure the necessary funding/capital to build the network and manages to incentivize a large percentage of homes to switch over and subscribe to their ISP.", "There's a concept in economics called 'Controlled Monopolies' and 'Natural Monopolies'. For certain industries, it's impractical to have much competition. For example, your electricity comes from a company like Eversource or National Grid or something. Walk around your neighborhood and see what that running that business looks like: power lines everywhere, electrical boxes, meters, underground cabling, running a massive grid. Imagine if there was like 5 companies to choose from for electricity. And each of those companies uses their own power lines, boxes, meters, etc. It'll look pretty crazy outside with all them cables! Dangerous too! So the Government steps in and says: \"Hey, let's make a deal. I'll let you be a monopoly - but I get to cap your prices and regulate you. Everyone wins.\" This is a controlled monopoly. This happens with industries that require a *lot* of infrastructure: water utility, gas utility - and now with student loans. Internet requires a lot of infrastructure, so most cities rarely have competition among providers. Internet isn't exactly a utility (yet) so it's not yet government controlled, however - it's a *natural monopoly*. Just because you're the only one doing it and there's no competition doesn't make it illegal trust. It just means there's a high cost to enter the market, and there's a lot of risk, so it may not be worth it. Some cities actually have government/municipal internet as their main ISP - like Chattanooga. And my hometown, Albany NY, had(has) a free wifi network throughout the city - Albany FreeNet.", "To do a quick synthesis of the great posts here, especially the one from /u/pythonpoole , the key to anti-monopoly laws in the US is that they are mostly about preventing the abuse of monopoly power, and less about barring monopolies outright. The law doesn't care if through the natural actions of the market there ends up being only a single sausage maker for the city of Weehawken. It does care if the Weekhawken sausage king tries to start a salad business and tells his current buyers that if they don't buy his salads, then he won't sell them his sausages."], "text_urls": [[], [], []], "score": [24, 4, 3]}}, {"q_id": "6il3w5", "category": "Repost", "title": "Why does time seem to pass much faster when you get old ?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dj71gvs", "dj71zlr", "dj735dk"], "text": ["When your 20.. 1 year of your life is 5%.. when your 50.. 1 year is 2%.. thats what i heard once from Dr Karl . On triple j", "This is partially caused by the fact you do not encounter as many new things in your life. For example: the first time you take some route from A to B, you probably remember the entire route. If you take the same route more times after that, each time you remember less of it, since it is a repetition of the things you already know (everybody knows the feeling that they come home but cannot remember exactly how, or at least, they do not remember the entire way). So you store less of your encounters, in comparison to when you were younger, since a lot of things you see or do are similar to things you encountered earlier in life.", "I always compare this to chapters and bookmarks in a novel. Everyone remembers when Dumbledore dies, but few people remember the conversations Harry had at the dining hall so many times and across so many novels. When we do not do interesting things in our lives we end up with big, hard to reference chapters. We sort memories by big events. Little things get remembered, but when you dredge them up from the depths of your mind there aren't much other things attached to it. The first part of our lives are full of memorable \"firsts\". First kiss, first drink, graduation, first time getting into a fight, etc... There are a ton of bookmarked and highlighted areas that we can review. New sensations and experiences that change us. Our brain itself is still changing so even the same event can be notable twice or more. And each event has a huge impact. A 50mb file is a huge amount of space on a 500mb hard drive. Later in life, your hard drive has grown to 500gb. That 50mb file is barely noticeable. Later on in life, especially if you live your life \"by the rules\", we end up with less of those. Sometimes there can be years between new and memorable events. Maybe a car crash here, a move across the country there... Everything in between sort of blurs together from all the empty space. We learn to integrate our experiences very easily. The second time moving across the country is just an inconvenience. The difference between \"Bookmark 340\" and \"Bookmark 341\" can be hundreds of \"pages\". Without milestones we lose our place \"in the book\". We just keep reading and only occasionally realize our eyes have been moving but we don't remember anything from the last 20 pages. An old man once told me, \"Why do most old people have regrets? **I've lived one year 74 times. Most people live one 74 year life.** It's easy to regret staying on the straight-and-narrow. What if this, what if that? I answered that question with action every time it came up. So... I never became a doctor, of course - Never real had the desire. But every old, retired doctor I've met wishes they spent a few years living like I do.\""], "text_urls": [[], [], []], "score": [3, 3, 3]}}, {"q_id": "6imgw2", "category": "Repost", "title": "What is the difference between socialism and communism?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dj7cpfk", "dj7c04f"], "text": ["In socialism the cows belong to the government in communism the cows belonng to the people.", "Generally, socialism is the belief that capital should be owned by the people/workers/government as group, rather than being owned by individuals or companies. Communism is a larger theory of history and economic development that predicts an ultimate end state of history where there are no longer economic classes (or government) and capital is held in common."], "text_urls": [[], []], "score": [4, 4]}}, {"q_id": "6io63e", "category": "Repost", "title": "If standard body temperature is 98.6 why is this an unsatisfying outdoor temperature?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dj7ql9v", "dj7qma2", "dj7rrfc"], "text": ["Because your body keeps making heat. If it's as hot as you are outside, it's hard for your body to transfer that heat to the atmosphere. Since your body is slower in getting rid of heat, and still making heat, you get hotter, and thus uncomfortable. Similarly, you get cold when it is cold outside because now the difference between your body and the environment is so great that you shed heat faster than you can produce it.", "Because we're constantly generating heat with our muscles and organs. Our primary means of getting rid of that heat is letting it disperse into the air via our skin. So while we are internally (on average) 98.6, we prefer an outside temperature below that (preferably far below) as it makes it easy for us to get rid of our heat which is being constantly produced. The world is our heat sink.", "Because \"room temperature\" (around low 70's F) is the point at which heat loss due to the environment is just about equal to the heat generated by your body. Lower than that, and we lose more heat than we are naturally generating, so we start feeling cold. More than that, and we can't lose as much heat to the environment as we need to maintain stability, so we start feeling hot. This set point can vary between people slightly (it's a common office environment between men and women) and notably its different for pets, ex. Cats have a higher resting point which is why they are always sitting around in sunny spots despite the room feeling fine to us."], "text_urls": [[], [], []], "score": [9, 5, 3]}}, {"q_id": "6iowpi", "category": "Repost", "title": "How come you can be falling asleep watching TV, then wide awake when you go to bed five minutes later?", "title_urls": {"url": []}, "selftext": "Edit: Fell asleep a few minutes after posting this. Woke up to 1,200 replies! I'm not going to get much work done today...", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dj88m8g", "dj80g96", "dj8al0i", "dj853rm", "dj81r04", "dj81jew", "dj85p46", "dj84tgz", "dj86e9f", "dj870nl", "dj8iyrn", "dj8hd9q", "dj8ehk6", "dj8s57d", "dj8v1jw"], "text": ["The brain is like a group of people talking to each other. When you're watching TV, the part of your brain that watches TV says \"Shut up guys, I'm watching TV,\" so you can focus without thinking about cake or math. As a result, the others sit silent, grow bored, and fall asleep, until only the TV watcher part of the brain is left. Left by himself, he too gets bored and falls asleep. When you're in bed, assuming you aren't counting sheep or something, the entire brain is kind of in free time mode, and any part of the brain can speak up if it wants to. They start talking to each other, and even if one of them starts to drift to sleep, the others wake it up either by deliberately talking to the sleepyheads or just being noisy. Eventually more and more of the parts of the brain fall asleep from sheer exhaustion no matter how loud the others are, and eventually the last one passes out and you are asleep.", "There was a post about this not too long ago. IIRC one of the reasons was that if you're lying on the couch and fall asleep, you're not actively trying to sleep, you just fall asleep because you're tired. When you go to bed, you're actively deciding to sleep, and thinking about trying to sleep actually keeps you awake.", "Since there's no empirical answer here, I'll throw my non-empirical answer in the mix: **TLDR: It could be many things.** It could be conditioning: You took a couple of naps on the couch with the TV on; now, your brain associates the TV, with just the right amount of fatigue, as sleep time, at the right place. Meanwhile, back at the ranch (when you go to bed), you're staring at your phone, \"doing some last few reddits\" before bed. You have trained your brain to activate before your \"alloted\" sleep time. Chances are, you've done so much internet before bed--your brain does not associate bed time with sleep time. Related: Your bed should be for two things only: Sex and/or Sleeping. This is to make sure your brain and body associate that with sleep, OR Sleep that usually follows sex. Also, digital screens emit blue light. In short, it's a light wavelength that suppresses melanin. Melanin is a hormone that is produced in your body. When Melanin spikes up (usually after some hours of nighttime and sometimes around post-lunch hours) it makes you sleepy because that's the job of Melanin. They also sell melanin at the drug store, but it's always better to rely on your natural sleep cycles as nature intended. The Sun and Digital Blue Light from most electronics today suppress Melanin, making it harder to fall asleep. **THIS** along with not associating your bed with sleep will most definitely fuck up your sleep. Sleep is still misunderstood for the most part (we don't know why we do it, generally), since it puts us at a huge disadvantage in the wild--yet, we **must** do it. This means that even if we don't understand it, it does something right. Studies where people were sleep deprived had slower time reactions, sometimes akin to a drunk person. For example, cell regeneration and healing happen during sleep. The brain, oddly enough, is more active during sleep. There's a theory that \"pruning\" is occurring during sleep--AKA, your brain is getting rid of the stupid, useless information that won't help you survive. This is why \"The First 20 Hours\" method works well for advancing learning quickly seems to do well: reviewing before sleep/reviewing after sleep, in short time frames--so the brain associates that this is needed and doesn't prune it. Another possible reason is that when you sleep, it takes some minutes (60ish or more on normal IF I recall correctly) to get to Rapid Eye Movement (REM sleep). REM sleep is **ESSENTIAL**. A lack of sleep with screw you up, but a lack of REM will really screw you up. So, when you're running on less sleep than usual, when you finally sleep/nap, you get to REM quicker! WOOHOO! LIFEHACK! **NO, it's not**. As stated earlier, sleep has a lot of functions. Anyway, if you're tired and fall asleep while \"relaxing\" watching TV, and wake up 30 mins later, chances are you got some REM sleep. This fucks you up because your body has gotten a little recharge to take you over for maybe, 6 hours? It's like your phone was dying, you charged it for 10 mins and got it to 25%. It's gonna take some time to get back below 10%. Remember those people from the studies? Well, some of them were \"disturbed\" (on purpose) during REM sleep (enough to snap them out of REM, but not out of sleep). The next day, they felt they were fine and had good rest. However, their results on reaction time showed that they were not at full \"normal\" rested reaction capability. Also, there have been many people throughout history that have experimented with various sleep cycles to \"get the most out of their day.\" I think (and I may be way wrong here) it was DaVinci that famously tried the polyphasic sleep (fancy name for \"different ways of sleeping\"), where he would sleep one hour every 4-5 hours. Supposedly it worked, and I don't doubt he got used to it. So, you may have gotten used to sleeping 4-5 hours at night, with a nap right after dinner--and you may not realize that it's a habit now. You may not like it, but you did to your body--your bod is just doing what you taught it. That's all I got. Some of it is scientific, but I did internet research long ago and don't have the patience currently to dig up the sources. If someone wants to disagree or bring up relevant points, or even call me out on wrong info, feel free. This is the internet, not The White House, I can admit I might be wrong. **EDIT:** I want to add that \"humming\" sounds can easily relax the brain. Depending on what you're watching, if it doesn't have much flux, the TV can hum along, much like a quiet lullaby. This is why White Noise or the sound of rain, a fan, Air Conditioner, beach waves, background coffee shop can aid in sleep & focusing. In a weird way, it zens the mind to relax. I looked into it long ago, but I forgot why it is. Probably something with the infant brain associating a smooth sound (singing by mom) that you are safe and not in danger, so you can relax. *EDIT 2** Guys, gals and all in between--I get it, it's melatonin--not melanin. I know the difference, I just have a long-life habit of mixing them up. That's what I get for doing a write-up on a lack of sleep. Happy naps, everyone!", "I think when you're watching TV, you're typically only passively using your mind. You're just taking in the info. So your brain isn't very active, yet there's something going on to keep it from becoming too distracted. Once you turn it off and try to sleep, your mind is free to wander and actively think about anything.", "People don't fall asleep, they arrive to sleep! When you were on the couch, you arrived to your sleepy ways because you were probably there for a little bit, comfy, and hadn't moved for a bit! When you moved to a new spot, your body must first adjust to your new spot, then it can arrive to sleep again =)", "Because when you get up from the couch to go over to your bedroom, you're up and moving again, which makes your body wake up somewhat. Happens to me as well. I'm on my computer late at night, feeling tired enough to go to sleep, but after I get up and go brush my teeth, I feel awake again when I get back to my room.", "Entering a sleep state while watching a tv show that you have previously viewed, familiar with and enjoy of enables the subject to fall asleep because of the passive distraction of focus principle. When your brain perceives something familiar with a known outcome while keeping a minimum level of attention it is easier for the brain to decrease activity and enter a rest phase. The same applies to highway hypnosis and redditing.", "The ideal window to fall asleep is actually pretty short. Around 10mn. You'll notice it if you start yawning, your eyes sting a bit. When you fall asleep in front of the TV, you may wake up at the end of that window. Then you have to do stuff to put yourself to bed. And the window is gone. And your body had to wake you up a lot. So you are wide awake. Try actually laying in bed and closing your eyes for 30s next time you catch yourself yawning late in front of the TV. Ez sleep", "One issue is that while sleeping with the TV on, you're conscious mind is being distracted of the stress and anxiety that you carry with you throughout the day. Instead it's trying to process the words being spoken, and so you don't have the mental chatter going on. The problem is that this then prevents you from getting into a deep sleep - so you're more tired the next day. That and when the sounds are removed, then you have the left-over stresses that you haven't dealt with bombard you all at once, because the artificial distraction is removed. Basically it tricks your brain into feeling better than it is. If you spent time process the stressors instead of watching TV - you'd probably sleep better and not fall asleep prematurely.", "The sleep cycle has a refractory period* built in that occurs just before the normal onset of sleep. This is designed to keep you entrained to the 24 hr cycle by preventing you from falling asleep a little earlier each day despite tiredness. It is easier to fall asleep both before and after that window. And watching tv is a relaxing sedentary activity. So you might be dosing off, then waking up when your body is resisting sleep. In studies on sleep deprived undergrads (most sleep research is done on undergrads) once allowed to they would fall asleep quickly - unless they were in their resistant phase. * I am almost certainly misusing this term here - I'm going off memory (and this is what my faulty brain keeps insisting on) but I think in the context of sleep research refractory period actually refers to a REM stage and a different term is used for the pre-sleep cycle entrainment stage. Sorry but don't have my sources at hand.", "Since the top comments seem to be anecdotes, I'll add one too. I've had lifelong sleep problems and I have participated in multiple sleep studies so I've got a decent bit of experience with specialists even though I am not one. The first step to correcting a sleep issue is always behavioral conditioning. You probably often watch tv late at night before bed so you're used to being tired in that situation. Bed is an interruption to your normal routine so it isn't quite as good as watching tv to your brain. If you were more in the habit of going to bed to get tired you'd get tired from going to bed, but it seems you watch tv late more often than heading straight to bed. If you spend a whole day busy and skip tv and go straight to bed, I bet you would get tired easier. I'm sure you've noticed this. If it was a regular thing you'd be able to sleep more easily when going to bed. In my experience with sleep specialists, I've been told to go to bed as soon as I figure out I'm tired to try to make sure going to bed works well.", "And this is why I drink most nights. Other than the usual \"it's my cure for depression\" episodes.", "I also want to know why I can be completely tired and lethargic all day, but as soon the twilight hits I'm bouncing off the walls.", "Wow I never realized this was a thing, and I do it every night. I finally go to bed (and although I fall asleep very fast) I think about how much I fought it (and failed) during a TV show. I always have to ask my wife what happened. The feeling of the fight is something I wish I could feel again once I laid down.", "This is an evolutionary trait that we never got rid of. Basically if you're about to fall asleep and then you get up for some reason, then your body is going *Well, shit, looks like we better get our asses moving then!* Imagine back when we weren't at the top of the food chain. It would be very necessary for our bodies to fully wake if we had to suddenly run for our lives."], "text_urls": [[], [], [], [], [], [], [], [], [], [], [], [], [], [], []], "score": [26588, 4136, 1508, 634, 371, 349, 58, 55, 34, 9, 9, 7, 5, 4, 4]}}, {"q_id": "6iqsvk", "category": "Repost", "title": "Why is it everywhere you go every church is the first? i.e. First Baptist Church.", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dj8d4df"], "text": ["Yeah why isnt there a 632nd church of god??"], "text_urls": [[]], "score": [3]}}, {"q_id": "6irnqj", "category": "Repost", "title": "\"Objects in mirror are closer than they appear\"", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dj8k1qi"], "text": ["This is due to car mirror's convexity. It enlarges the field of view, but shrinks everything it captures. Therefore, we can see more things, but they are smaller. Think of it as a mirror.rar ;) Sof if you see something small in a mirror, you will assume that it is rather far away. Thus, \"objects in mirror are closer than they appear\"."], "text_urls": [[]], "score": [7]}}, {"q_id": "6isosi", "category": "Repost", "title": "Why is it that when you are laying in bed, just about to fall asleep, you sometimes suddenly feel like you are falling and jerk back up fully awake?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dj8qp29", "dj8qe96"], "text": ["This is known as a Hypnic Jerk. It occurs most commonly in people with messed up sleep schedules or heavy caffeine users, but can happen to anyone The prevailing theory on the cause, is a lingering evolutionary instinct from our days as early primates in trees. As your body relaxes, your mind can mistake the subtle shift as a shifting branch, and jerks you awake to ensure you catch yourself.", "It's pretty common, though it doesn't happen to me as much as I've gotten older, which may be related to me having a better sleep cycle now. It's called a [hypnic or hypnagogic jerk]( URL_0 )."], "text_urls": [[], ["https://en.wikipedia.org/wiki/Hypnic_jerk"]], "score": [11, 3]}}, {"q_id": "6it9li", "category": "Repost", "title": "Why are all baby animals really cute?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dj8usek"], "text": ["Because most baby animals look pretty similar. We have a predisposition to care about our young. This is good for our species, given that babies can't care for themselves; we need to have a desire to be around them and care for them else our species won't be surviving very long. Baby animals share many of the visual traits that baby humans have - smaller bodies compared to their heads, disproportionately large eyes, etc. Our innate desire to care of our young isn't all that fine tuned, so we tend to project those feelings onto anything that meets the basic criteria. This isn't limited to just baby animals - we also care about adult animals that meet those criteria and many [inanimate objects]( URL_0 ) that fit the bill."], "text_urls": [["https://www.cstatic-images.com/car-pictures/xl/CAB90VWC051B1101.jpg"]], "score": [3]}}, {"q_id": "6iumeo", "category": "Repost", "title": "What are burns? And how does fire burn people?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dj9669p"], "text": ["Most of the fire we see is the result of something called oxidation, meaning that it is energy released by combining oxygen with something other chemical (usually carbon). So, when wood is burning the energy added to the wood allows the carbon in the molecules that make up the wood to break apart, combining with oxygen in the air, turning the wood into ash and releasing more energy to keep the reaction going. Burns are roughly the same thing. You end up somewhere where it's so hot that the molecules in your body start to break apart. Sometimes they just malform, sometimes they actually burn the way that the wood burns. But, either way, the part of you that was burned is no longer the same at a chemical level. The more that gets burned, the more of your body stops working, and the more likely you are to die. Burned skin can't stop infections, burned organs don't work, etc... That said, some symptoms of burns are part of the bodies reaction/attempts to heal. Something like a blister is the body trying to repair/contain the damage from a burn."], "text_urls": [[]], "score": [3]}}, {"q_id": "6ivdp7", "category": "Repost", "title": "Where does gold derive its value from? Is it an entirely human construct?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dj9cf7e"], "text": ["All value is a human construct, unless you want to include the supernatural (like God valuing love). In this plane of existence, nothing has any value except because people say so."], "text_urls": [[]], "score": [3]}}, {"q_id": "6ivhch", "category": "Repost", "title": "What's the thinking behind not evacuating if there is a fire?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dj9e1c9"], "text": ["In high rises, they are supposed to be built such that fires are contained to the unit or floor for quite a period of time (here in Chicago, each apartment/condo has to be fire rated for 2 hours, ie. a fire could burn unchecked for 2 hours within a single unit before it would begin to spread). As such, because it's important to get fire crews in and evacuate those that were injured or in immediate danger quickly, orders are for those further from the fire to shelter in place. Imagine firefighters trying to get up the stairs to a fire on the 20th floor while 1000 people are racing down the same stairwells. And really, only 50 of those are in more immediate danger... so only evacuate those at first, then assess. So high rises get evacuated in stages, as necessary based on the fire. I lived in a high rise for 12 years, and in that time we had 4 serious fires that gutted units. They typically evacuated the floor itself, and those directly above and below at first. In fact, in one, my uncle lived on the floor where the fire took place and they just told him to place damp tower at base of door and stay in place unless told to evacuate."], "text_urls": [[]], "score": [10]}}, {"q_id": "6iy48y", "category": "Repost", "title": "Why do planes fly high up, wouldn't there be a shorter distance travelled the closer to the ground they fly?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dja0kcg"], "text": ["difference in distance traveled is negligible, they fly about 7 miles high earth is about 7000miles in diameter. circumfrance of the earth is then 21980. add 14 miles to that diameter for the distance the plane flies is 22024. so a full lap around the entire earth would only be 44 miles farther than at ground level. Negligible. flying at height means much lower air pressure, which means less drag, far better speed and fuel efficiency which majorly offsets the slight distance, plus spends less fuel, and it makes less noise pollution for people on the ground."], "text_urls": [[]], "score": [6]}}, {"q_id": "6iybw2", "category": "Repost", "title": "Why does soda taste differently from a bottle, can, and a fountain, when it should be the same drink?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dja2f4t"], "text": ["It's all about mixing and storage. Fountain soda is the freshest possible mix, right before you drink it. Bottles and cans both provide good storage and consistent taste, but since it's mixed long before it's consumed it doesn't taste as fresh in either of those cases. Besides that, cans for drinks are lined with a plastic barrier to keep the metal from leaching into the drink, and that may still leave a different taste from a bottle or a fountain."], "text_urls": [[]], "score": [3]}}, {"q_id": "6iyint", "category": "Repost", "title": "human brain has a capacity about 2.5 petabytes. Hypothetically speaking what would happen if they are filled? Would we stop remembering new things or would we start erasing old memory to make room for new memory?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djaaux4", "dja6nin", "djad27n", "djaidi2"], "text": ["As far as I am aware, no physiological basis for a hard storage capacity of the human brain has been established - that 2.5PB may be an extrapolation of our current model of how we encode memories, but ultimately the brain stores many different kinds of vastly different data in a variety of ways that remain elusive to us. It's not a hard drive, and a huge amount of data storage and recall seems to happen through associative relations between systems of neurons, not state changes in individual neurons. tl;dr- nobody has ever \"filled up\" their brain. Old knowledge and skills atrophy and become harder to recall if they aren't used, but that's not the same thing as being absolutely unable to learn new information, or \"deleting\" old knowledge, without an external cause (such as dementia or TBI).", "Here's my take given a psychology background: memories are created in the hippocampus, specifically in the dentate gyrus. This area creates new neurons that can hold information. Assuming this area is not longer able to stuff more neurons in then you'd lose the ability to form new memories. We already see this as it becomes harder to learn new skills as you age. Assuming it was completely full you'd probably suffer from complete anterograde amnesia. Meaning, every time your short term memory empties, you'd forget everything that happened. There's actually a case study on someone who had this known as H.M. He would be able to perfectly recall his wife and know exactly how they met and so forth but, he'd forget every few minutes what had just happened. He had a journal that he would repeatedly write \"I am now fully awake\" and other iterations of this constantly. But, that's assuming that there isn't a cleanup system for neurons.", "Off-topic: with good compression, and counting about 16-17 active hours per day, you could store an HD video recording of every waking moment of an average life (in POV perspective) from birth to death in about 4 petabytes. Just a neat fact. One thing that's been experimentally verified is that as pattern recognition becomes more attenuated over time, aspects of memories become both more solid and more vague. For instance, if you have a portrait on your wall in a hallway, and you pass it every day, your peripheral exposure to the picture solidifies bold elements like the frame and the face, but blurs elements like the facial features, simply because you *stop noticing it*. That's how you can navigate a well-traveled hall in the dark, but pranks like replacing the portrait with a similar, but different face can go unnoticed for so long. Experiential learning is good at environmental stuff, but bad at details for most people. In addition, the more you access a memory, the more it degrades, and it can be modified or changed if repeatedly accessed. See the stories from people who were convinced they experienced child abuse in the 70s from Satanic cults. ELI5: Memories are fickle, and 'data storage capacity' is not a good measure for human brain capability because the brain is always in flux. Edit: a word.", "Looking for the specific pieces of the brain that store memory is like looking for the specific pieces of a piano that store music. Brains don't really work like hard drives. In fact it looks like an essential part of learning is deleting irrelevant information. Which of course makes sense. You want to remember stuff that helps you out, like where to find a safe bed or where to find food, or what kinds of animals are dangerous. It's very difficult to figure out what's important if you keep everything that isn't important too. So the answer to your question (as much as it can be answered) is that every part of you consciousness is dedicated to selecting which memories to keep and which to drop, and it starts the day you're born."], "text_urls": [[], [], [], []], "score": [32, 17, 5, 3]}}, {"q_id": "6iymc9", "category": "Repost", "title": "when is space where there is nothing but emptiness, what do rocket engines thrust against that make them move forward?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dja5352", "dja4u9p"], "text": ["The rocket engines push against the exhaust that is being expelled. For every action, there is an equal and opposite reaction. It's exactly the same as if you were wearing ice skates (standing on ice, obviously) and holding a bowling ball. If you throw the ball forward, you'll slide backwards. This is not because the bowling ball is pushing against the air. It's because when you push the bowling ball forward, you're also pushing yourself backward. With a rocket, the exhaust from the engines is the bowling ball.", "The fuel of the rocket being expelled out the back of the rocket pushed the rocket in the opposite direction. Newton's Third Law of Motion in action."], "text_urls": [[], []], "score": [9, 3]}}, {"q_id": "6iz5mn", "category": "Repost", "title": "The difference between the (US)Marine Corps and (US)Army?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djaanjs"], "text": ["> Both organizations seem to be deployed to the same theaters doing the same jobs. The nature of current wars - fighting insurgents on land - is largely why they appear to do to the same jobs. Historically though, the two have served and occupy very different military and political roles. Let's start with the Army. The [mission statement of the Army]( URL_0 ): > The U.S. Army\u2019s mission is to fight and win our Nation\u2019s wars by providing prompt, sustained land dominance across the full range of military operations and spectrum of conflict in support of combatant commanders. The key word there - *sustained land dominance* - is what the Army's mission has always been. They're the force that is designed to take *and hold* land, hence their large manpower in times of war. Historically speaking, the US Army was founded as a small standing force that would be augmented in times of war with militias (the modern day National Guard) and through conscription (as was done in WWI, WWII, Korea, and Vietnam). Even today, this tradition still exists: the Army has a majority of its forces coming from the National Guards of each state and the Army Reserve (460,000 active duty Army versus 530,000 reserve + National Guard). Up until 1947, the Secretary of War - a cabinet position - headed the War Department which governed Army (and Army Air Forces) affairs. The Secretary of War was NOT, contrary to popular belief, the predecessor of the Secretary of Defense. He, along with the Secretary of the Navy (which became a cabinet position in 1798), were both members of cabinet and each dealt with their own affairs. Secretary of War was also aptly named: with an army designed to be small until times of war, his purview was in matters of land warfare, a rarity in North America in comparison to European affairs, and which only came in times of outright war. Why do I bring this up? Well, lets contrast that to the Marine Corps [mission]( URL_1 ): > As America's expeditionary force in readiness since 1775, the Marines are forward deployed to win our nation\u2019s battles swiftly and aggressively in times of crisis. We fight on land, sea and air, as well as provide forces and detachments to naval ships and ground operations. *Expeditionary force* and *in readiness* are big key words here. An expeditionary force, unlike the Army, is designed specifically to be sent overseas. In readiness also means that, unlike the Army, they are designed to be in an active state without needing to go through mobilization (the calling up of reserves, conscription, etc.). Ever since the nation's founding, the US Marines have been a part of the Department of the Navy (cue jokes about how the Marines are the *men's* department). That's right, both the Navy and Marines report to the Secretary of the Navy. Why was this? Well, Marines were designed specifically to be naval infantry, as in a ground force serving on ships that could defend the ship during a boarding attempt or board other ships when trying to capture them. And, in the event of needing to put forces ashore, the Marines would be the ones sent in. Remember, until long-range aircraft were invented, ships were the only way to get people across the oceans. Navies might be operating thousands of miles away - and back in those days, months of communication away - from home. Naval warships and the Marines on board had to be self sufficient. Thus, you see the roots of the Marine Corps' *expeditionary* nature. And, since sailing a ship isn't something that can be done at a moments notice (training a crew to fight as a cohesive unit takes time, and leadership takes years to develop), we see that the Navy has always been designed to be an active duty component of military forces, something you find around the world really. (Historically speaking, even in feudal societies, navies would be under the direct control of the monarch - hence the Royal Navy - even while armies would be levied from various lords underneath, because navies needed to be *professional* forces). And since naval infantry can't just be levied from the populace when ships are thousands of miles away from home, the Marines were designed from the onset to be the *professional* ground fighting force that would project power from ships. The portion of forces that are active in the naval services speaks for itself too: Branch | Active Personnel | Reserve Personnel ---- | ---- | ---- US Army | 460,000 | 530,000 US Navy | 323,000 | 108,000 US Marines | 182,000 | 38,500 US Air Force | 313,000 | 175,000 I put the Air Force in there, because they carried on a lot of the legacy of the Army with them (such as their own National Guard... the Air National Guard) while also requiring professional personnel given the technical nature of their branch. The final piece of the puzzle is that of self-sustainment. The [vision, per USMC HQ]( URL_2 ) is: > To be the premier self-sufficient expeditionary force, instilled with a warrior ethos that equates the efficient use of vital resources with increased combat effectiveness. Self-sufficient expeditionary force is why the Marines have both ground forces as well as air forces. They have their own helicopters for transport and combat. They have their own fighter jets and attack planes as well. The Marines have the Marine Expeditionary Unit which consists of ground forces and air forces operated from Navy amphibious warfare ships that can sail around the world and respond to any crisis at a moments notice. They are also designed to carry enough supplies with them to sustain a fight without outside support for 30+ days. Of course, self-sustainment doesn't include the fact that they have to ride on Navy ships (as they have historically done), hence the joke that MARINES stands for 'My Ass Rides In Navy Equipment, Sir' but I digress. In sum: * The Army has been designed to be a large land force that requires periods of mobilization to get it to full strength for warfare * The Marines have been an expeditionary (overseas-focused) force transported by the Navy that is in an active state, i.e. ready to go without periods of mobilization."], "text_urls": [["https://www.army.mil/info/organization/", "https://www.marines.com/who-we-are/our-purpose.html", "http://www.hqmc.marines.mil/e2o/Mission-Vision/"]], "score": [3]}}, {"q_id": "6izh4y", "category": "Repost", "title": "Why do we hear ourselves different when we talk vs. in a recording?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djabpim", "djad1vn"], "text": ["When you hear yourself talking normally, you also hear/feel the vibrations of your voice in your own head. You aren't just hearing your voice go into your ears from the outside.", "Your skull makes your voice sound different to you. The vibrations travel through the skull and change in pitch and tone as a result. What you hear on a recording is the actual sound of your voice to other people."], "text_urls": [[], []], "score": [4, 4]}}, {"q_id": "6j01qr", "category": "Repost", "title": "What exactly are the moles on your body? Why do we need to go through surgery to actually remove one?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djakus8"], "text": ["A mole (or melanocytic nevus) is an often benign local overgrowth of melanocyte cells. Melanocytes are the cells responsible for making melanin, a dark skin pigment. That's why many moles appear brown or dark - the large number of melanocyte cells make lots of melanin, which give the mole its colour. There are numerous types, some depending on which layer of the skin the cells are from. Usually you're either born with them or you get them within the first 20 years of life, then they tend to stick around. We go through surgery to remove them for two reasons; either the person with the mole wants it removed for cosmetic reasons, or a doctor suspects the mole may actually be a melanoma - a particularly nasty type of skin cancer. If there's any indication the mole is a melanoma, it's removed, usually with negative surgical margins, which means you cut out an area of skin around the cancer that contains entirely normal cells (so you can be sure you cut it all out and didnt leave any behind). The removed bit of tissue is then sent off for testing to see if it is anything to worry about or not - that's called a skin biopsy."], "text_urls": [[]], "score": [62]}}, {"q_id": "6j0boz", "category": "Repost", "title": "Why, when playing a song repeatedly, do we tend to get tired of hearing it, then can enjoy the song again after a break?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djalhkd", "djapae0", "djb3acn", "djb2czb"], "text": ["The general theory for this is that our brains thrive from predicting. This is why you might not like a song initially, but after a few more listens you start to love it because you can predict where the song will go next. But it also works both ways; listening to a song hundreds of times results in diminishing returns of satisfaction from predicting it, because it's become 'hard wired' into your brain. Then you take a short break, so you can enjoy the song again because you can't remember all of it anymore, and your brain enjoys trying to predict what will happen next again.", "Three important functions of our brain 1. detect patterns 2, predict outcomes 3, detect change All of these help us to recognize / avoid danger Our sensory systems are designed to respond when input changes- for example, when the thermostat of an air conditioner goes on, we hear the hum. And then when it goes off, we hear the silence. These responses to change need to be noticed- since changing conditions are potentially dangerous After a minute of hum/ silence the receptors adapt and shut off. On a higher level, when we listen to music or see art, we initially make predictions about what will come next. When the music or art is unfamiliar, the next earful or eyeful is a surprise. So we attend closely . Once the information becomes familiar, we can predict its entirety with a brief glance or short sample of sound. It has no novelty and is becomes less interesting. Even just seeing the title on a playlist evokes the memory of the entire composition. We apply our attention to new information. (Source: URL_0 )", "An equal question is why some songs don't impress us initially, but can grow on us after repeated hearings. I think the predictability plays are part here in opposite ways. Back in the day The Rolling Stone would get prerelease's of albums to review them. Some of the best selling albums in history received poor reviews. Many of them are now on The Rolling Stones top 500 albums of all time. The Beatles often argued about future iconic songs and whether they should be put on an album because the guys that didn't write the songs thought it was subpar. (e.g. As my guitar gently weeps) Also many super hits sit on the shelf for years even tho many hear it and pass on recording. The country song of the year Whiskey lullaby was like this. The Hallelujah Course written and recorded by Leonard Cohen was ignored for years by more mainstream recording artists.", "I don't listen to the radio much, so I mainly hear new songs and artists through my girlfriend or on weekends at a bar. It's so frustrating hearing a song that has been out for a month and being told, \"This is so old, turn it off.\" Then they play Sweet Caroline or Wagon Wheel and the crowd goes nuts... A song isn't old because it's over played. The song is old to YOU because YOU overplay it/don't switch stations or press next on your playlist!"], "text_urls": [[], ["https://www.quora.com/What-happens-in-the-brain-when-you-get-tired-of-a-song-after-listening-to-it-a-lot"], [], []], "score": [399, 26, 13, 4]}}, {"q_id": "6j0d0b", "category": "Repost", "title": "Supercharging a Tesla takes 20 minutes to 50%. Why does 100% take 75 minutes and not 40?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djauulo", "djav7dq", "djaii2n", "djav7zh", "djaq0rw", "djasbes", "djaiu0z", "djb4jc1", "djb0100", "djanpjx", "djalhyt", "djaxi81", "djb3zk6", "djaqmmq", "djauc9a", "djbaffd", "djattew", "djb58b6", "djavexq", "djavfns", "djasayb", "djast4l", "djb4cc5"], "text": ["[Wile E. Coyote is preparing a spring loaded boxing glove in order to catch the road runner.]( URL_0 ) At first it's easy to press the spring back into it's 'loaded' position, but the closer he gets the more effort he has to put forth. As he nears the hook it takes all his strength to move a few inches. The same is true with these batteries. Basically, as it increases in charge it must overcome more and more resistance, so the battery charges slower the closer it reached max charge.", "The analogy I like, as an electrical engineer, is making a stack of objects of equal weight. Imagine stacking bags of flour from the bottom up. I think this is a pretty accurate analogy, as lifting an object gives it potential energy, the same way charging a battery gives it potential energy. First, imagine you have one bag of flour on the floor. Then to put a second bag under it, you have to lift that one bag the height of the bag below it. Pretty easy! To put a third bag into the stack, you now have to lift two bags to the height of one bag, and put the third under. A bit more difficult. Then for a fourth bag, you're lifting three bags to the height of one bag, and so on. It gets progressively more and more difficult to put an additional bag of flour under the stack, because you're lifting another bag each time. For a bit more accuracy, consider you only have a certain amount of energy per unit time. Like, you can only ride a bike so fast. So let's say you power the flour lift system with a 10-speed bicycle! The first bag is possible to lift in the highest gear, (the one that lets you go the fastest). For the second bag, it's too heavy, so you switch to the next lowest gear. You have to pedal longer to get the wheel to spin the same amount, that is to cover the same distance, so it takes a longer time to lift the two bags. Then you change gear again for each successive bag, so you can pedal at the same speed, but as a result, it takes longer to lift each successive bag. Edit: To those who mentioned the water level/pressure in a column analogy, I fully agree with you that it's a more accurate representation of the system, and it's the way I usually try to explain it to engineering students. So if you're interested in a more mathematically consistent explanation, do check out the comments below! And indeed, the power and energy concepts are not totally consistent here, so if you're an engineer/electrician/etc., I understand if you disagree with the explanation. In the interest of ELI5, I think something more discrete, like stacking objects, and one a child may have held in a grocery store, is easier to understand than a constant-pressure pump with an increase in water pressure at the bottom of a column as the water level rises, as far as RC type circuits and exponential rates are concerned.", "Batteries do not charge linearly. The fastest portion of charge happens at the beginning. Without getting too sciencey, this is because the rate of charge is based on the difference in charger voltage and battery voltage. The larger the difference, the faster the charge. As the battery charges, that difference continuously gets smaller, so it charges slower. This is demonstrated in the following chart: URL_0", "Imagine you want to understand how Tesla Supercharging works by reading analogies on Reddit. Reading the first couple of analogies is easy and gives you a basic understanding of the subject. To gain a better understanding you need to read more analogies, however the more you read, the more you lose the will to read analogies, and the harder it becomes to learn.", "The 5 year old explanation is, imaging you're running in a 100m dash, but at 101m is a brick wall. You run as fast as you can at the start, but start slowing down when you approach the end, as to not hurt yourself.", "When your Tesla is low on charge, it is very thirsty and drinks it's energy drink very fast. The more it drinks, the less thirsty it is, and the slower it drinks.", "First, this comment is generic lithium-ion battery information. It is not Tesla specific. It is for safety and for extending the lifetime of the battery. A battery pack can be destroyed and may catch fire if even one cell is over charged. Most Li-ion chargers use two charging methods. First, a constant current is applied until the battery reaches around 4.2 volts/cell. That is the fast charge. Then the voltage is maintained at 4.2 until the current has dropped to a certain level- somewhere around 10% of fast charge. Then charging ends. This second charging method takes longer because as the battery becomes charged the current naturally drops because there is a smaller difference between the charging voltage and the open circuit cell voltage.", "Tesla owner here. While the top voted explanation is great at being simple, unfortunately it's grossly incorrect. The battery doesn't take more \"effort\" or have more resistance as it fills up. Actually when it's charging near max and going slower, there are less resistive losses due to heat, less energy wasted on cooling fans, and less effort put in by the charger. Here is the correct explanation: Think of a battery as a bucket. I can fill the bucket with a firehose, but only very briefly before it starts splashing out. Once I turn off the firehose, the bucket might be ~%60 full. So I switch to a slower garden hose on full blast. Now I can get the bucket to 95% before water starts splashing out. To get that last bit up to 100% I'll use a trickle from a faucet. Water splashing out of the bucket (overcharging) is very bad for the battery so the charging system deliberately slows down to avoid this.", "The analogies are terrible. What's the point of answering if it is plain wrong? It takes longer to charge because there is a voltage threshold. Once you reach that threshold, the current gets lower V=R * I. As you charge the battery, its internal resistance rise. Once you reach the limit of 4.2 (it is actually 4.3/4.4), the current will slowly get lower as the resistance increases (V=RI). Lithium-ion batteries don't like 3 things: being over charged, over discharged and stressed (too high current). When charging, you don't apply right away the threshold charging voltage as it would generate too much heat due to the high current. However, the batteries can accept A LOT of energy very fast that way. At the end, you can't ramp up the voltage to prevent damage to the cell. When you charge the battery, lithium ion travel from one metallic plate to the other. There's something in between that prevent the plates to touch each other (very bad, short circuit). When the ions move, they heat every thing around them (good analogy: friction). If you increase the voltage, you make those ions travel MUCH faster. They collide with every thing around them and it can damage the thing preventing short circuit. This is why you try to keep the voltage / current at a specific value that the cell can handle safely. As for over charging (maximal voltage) I believe it is to prevent unwanted reactions. I've read that tiny crystal can form on the plate and it can puncture the thing preventing the two plates to short circuit each other if the cell is over charged.", "Picture you have 100 boxes that fit perfectly in an enclosure - no extra room. It would be pretty easy to just throw like 60 boxes in there right? But it takes much longer to use up every bit of available space and put the boxes in perfect position.", "Electrons all have negative charges, and as a result they really don't like being next to each other. When you are charging a battery, you are pushing electrons into a confined space where they are forced to be really close to each other. That's easy at first, but it gets harder as time goes on. It's an exponential curve, which means that pushing in a few electrons makes the next few much harder to push in. You can imagine it like trying to pack stuffed animals into a cardboard box. You can get a lot in there if you try hard, but while the first few will be really easy to get in, they will resist your efforts when you try to put in the next few, and so on.", "How fast can you fill a pitcher of water up to the rim (without overflowing) using a kitchen faucet? Filling the first portion is easy, turn the faucet on fully. The water will be frothing around, but since there is so much space, you won't spill. However, when you get closer to the rim of the pitcher, you have to slow down the faucet stream to prevent water from overflowing. To get the last 1% of water in without spilling, you'll barely be dripping water into the faucet. Batteries are the same way. 'Spilling water' will damage the battery, hence the trickle charge when the battery is 90%+ full.", "What everyone says is technically true, but not really the case here when talking about Tesla battery packs, which are a bunch of little battery cells in parallel and in series. The real reason it takes so long is because of balance charging. That's literally the answer to your specific question. When all the batteries are low, you can bulk charge them to around ~4 volts-ish depending on the batteries, their health, and the charge controller. The time has nothing to do with how much energy is being put in and it's potential in this case. The issue is the batteries in series can't just all be charged up to 4.2 at the same time, internal resistance of the battery and the health of each cell determines how fast each individual cell will reach 4.2v. Now, if one hits 4.2 while another is still 4.1, that 4.2 needs to be discharged back down to 4.1 by literally wasting and burning off the energy, which takes time because if you do it too fast, you'll burn up the charge controller from heat build up. Once you get to the last couple millivolts, it's basically a balancing act, literally. The batteries are connected at the different points in the series, and each point gets a different voltage, so you can charge individual series packs of parallel batteries. You have to wait for everyone else to catch up before you can reach that final 4.2v and call it done. That last portion is all charge, discharge, charge, discharge, charge, and probably discharge one more time until they are all balanced. If not, you'll end up with dead cells, or even worse, exploding cells that no longer can keep up with the other cells. But they use very thin wires between each cell, so worst case scenario, the cell pulls too much current and the wire melts on purpose and the cell is now disconnected. They could technically \"fast charge\" the batteries, but at the risk of destroying a $12k battery pack just to be impatient and charge all the cells in bulk. Some will hit 4.2 first and keep going up while the others keep the total voltage below the cutoff. Once the last of the cells get to 4.2, the first ones will already be dangerously high and will after a few cycles be dead.", "Imagine you are raking leaves. You take one swipe with the rake and get half the leaves. You take another swipe and get more leaves, but there are still a lot left. You take a third swipe and now there are just a few stragglers, and you get those with the forth swipe.", "So many analogies. So many.... I like the piling into a train in Japan one the best. But the real problem is that once it gets harder to shove people in the train, the battery starts to heat up. A lot. This can, and will, damage the battery. Specifically, it burns up the micro fine wires going to individual cells and as those wires burn up those cells get disconnected and the battery becomes \"smaller\".", "a battery is like a ball or tire you're filling. the fuller it is, the harder it gets to press more air in.", "Imagine that the batteries are sponges and you are trying to get them to soak up water until they are 100% full. When you first start putting water into the sponges it soaks in very quickly but then slows down as the water has to diffuse from the outside to the inside. Lithium batteries have a similar pattern when charging where the charge has to equilibrate into the battery.", "Imagine eating one pizza in 20 minutes. Now try to eat another one in the same amount of time.", "When you fill a pitcher, do you slam it full speed to the top or do you slow it on down as you get there?", "Imagine breathing in. You can fill your lungs to 75% in a few seconds. Then you need to swallow small gulps of air to fill up any further.", "Imagine you are filling up a cup of water. You pour the water into the cup with a pitcher and at first you can pour quick, but as you get closer to the top you slow down because you don't want to make the cup overflow and spill water everywhere.", "If you imagine the flow of electricity to be water, then you can think of voltage as pressure, and amperage as volume. A low amperage, high voltage line can be thought of like a hose, with your thumb over it. The amount of current is small, but the \"spray\" of pressure can be large. Likewise, a low voltage, high amperage current is kind of like an overflowing sink. Lots volume, not much pressure. Finally, there's one more factor to discuss: impedance. This is the amount of resistance the current must overcome to flow through, or to, a particular device. In our water metaphor, for most things the impedance would be 14 psi (atmospheric pressure at sea level). But for electricity, the impedance can vary, based on the type of material. Now we come to our battery. Think of it like a balloon. At low charge, it has low impedance. There's not much charge in there, so there's little 'push-back' when electrons flow in. As the battery charges, however, impedance rises, increasing the amount of pressure (voltage) required to maintain the rate of charge. If the impedance rises, and the voltage stays the same (which it does, for safety reasons), then the rate of charge will decline.", "One of the ways you can picture electricity is like water. Voltage would be like water pressure, the difference between simply pouring water down a garden hose and connecting it to your house's water. For the same size hose, or tube you can get more water in the same time with more pressure since it makes the water move faster. Now, imagine that the battery is like a big inflatable pool, and the only way to fill it is connecting a hose to the side. At first there is very little resistance to the water rushing from the hose so it fills fast. As more water fills the pool the water from the hose is being resisted by the water in the pool slowing the flow, so you get less water going in. You can't turn up the pressure or you will damage the connection from the hose to the pool and make a big mess! For the batteries in a tesla, or a laptop, or your cellphone there are some electronics that are responsible for safely charging the battery so that it is not damaged. Batteries heat up as they are charged, for the same reason many other electronics do; they always have a little resistance to the flow of electricity, and that resistance turns some electricity into heat. Also like the pool there is a maximum voltage (pressure) that you can use when charging or you risk damaging the battery. So early on the resistance to charging is low and the battery is cool you don't need maximum voltage to charge fast, but once the voltage reaches the limit (because the battery has more 'resistance' to being charged further) you have to let it charge slower and slower. You also need to slow down the charging if the battery gets too hot so that you don't damage the battery."], "text_urls": [["https://www.youtube.com/watch?v=MenKyfGvtvk"], [], ["http://www.progressivedyn.com/images/page_graphics/charge_wiz_curve.gif"], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], []], "score": [14116, 6597, 2619, 2468, 341, 329, 326, 171, 75, 70, 12, 11, 10, 7, 6, 5, 4, 3, 3, 3, 3, 3, 3]}}, {"q_id": "6j11ph", "category": "Repost", "title": "[maths] What are imaginary numbers? How do they work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djanrnf", "djamog2"], "text": ["Starting with just the counting numbers (1,2,3...), everything is easy But then subtraction comes along and people say, what happens when you take a bigger number from a smaller number? So we invent negative numbers. Then, later we start using division, it's mostly ok, but what happens when we divide two numbers that don't factor into each other? Bam, fractions. Even later when discussing square roots, we realise, huh, what happens if we square root a negative number? Presto, imaginary numbers. Why is this step so different from the others? Just because it has the word imaginary in it? As far as usage, many equations describing electricity and current uses it. And it's a great way of getting patterns that kinda look like 1, 0, -1, 0, 1, etc", "They are not arbitrary. They sort of \"fill in the blanks\" when doing math. They are also very important for physics and other sciences. It appears in the Schrodinger equation (very important for modern physics). What is the solution to the equation X^2 +1=0? It is a meaningless question with no answers if you stick with real numbers. That is why complex numbers were developed. BTW the square root of negative one is the definition of i."], "text_urls": [[], []], "score": [10, 3]}}, {"q_id": "6j1nih", "category": "Repost", "title": "If the scope on a rifle/gun is 2-4 inches above the barrel why does it predict where the bullet goes so well, even though it is above the barrel (where the bullet exits from)?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djarak5", "djardui", "djar8sg"], "text": ["Because the bullet takes a ballistic arc path. Scopes have to be \"zeroed\" or \"sighted in\" so that certain distances in the scope intersect with that ballistic path. Light travels in a straight line, but a bullet out of a gun is angled slightly up so that that it is rising for the first half of its flight, then falls for the rest. Because of this, there are 2 points for any zeroing distance where the bullet will pass the plane you see through the scope, one on its way up, and another on its way down. If you're shooting at a distance other than these two ranges, you need to make eyeball adjustments on the fly (also known an \"Kentucky windage\") or use the knobs on the side and top of the scope to actually adjust the aiming point of the scope to match where the bullet will be at that distance. [This image]( URL_0 ) shows the basic premise. Notice in the image that the bullet is striking the target at the second of the two intersections, on the downward path of the bullet. The first one is much closer. There are different ranges that one can sight in or zero their rifle two, and with some knowledge of how long the barrel is, what type of bullet is being fired (and some other factors if you want to be hyper accurate, like air temperature, humidity, ground elevation) one can predict what ranges these twe points will be with remarkable accuracy.", "Because someone took the time to sight it in. There is actually 2 points where the scope will be right on with the bullet path. One where the bullet is still traveling flat or up compared to the line of the scope and another when the bullet falls back into that line again.", "The internal alignment can be adjusted by the top and side knobs. This is what's called sighting in."], "text_urls": [["https://upload.wikimedia.org/wikipedia/en/a/a8/TargetShooting3.gif"], [], []], "score": [18, 4, 3]}}, {"q_id": "6j26rb", "category": "Repost", "title": "Why does El Salvador use the $USD as their currency ? How does this benefit either country ?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djawz8l"], "text": ["Stability. Having a weak or volatile economy is bad for business. Business owners what to be reasonably sure what they buy today they can buy for about the same price months from now. If high inflation or a fluctuating currency means they can't do that, they have to be much more cautious, and that slows economic growth. When this gets too bad, businesses and consumers will start to shift to a more stable foreign economy like the US dollar or the euro. If this goes on too long, the foreign currency can become a de facto standard. This starts off as being widely accepted (most of the Carribean), and in some places can be the unoffical standard (Belize, Cambodia). Some countries try to fight it, Vietnam is currently trying to get more people to use the local currency and stop listing prices in dollars. Other countries, like Ecuador and El Salvador, simply give up on their own currency, make the USD official."], "text_urls": [[]], "score": [5]}}, {"q_id": "6j2yc6", "category": "Repost", "title": "Why Liquid Glue Doesn't Stick to The Inside of The Bottle", "title_urls": {"url": []}, "selftext": "What's the science behind this? If there is any...", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djb2hnh", "djbdhlb", "djbany9"], "text": ["It's because liquid glue doesn't stick to anything. It isn't until the water (in white glue) evaporates that it actually adheres to anything. In a bottle, The water cannot evaporate, so the glue can't stick to the bottle. If you leave the lid off, it can evaporate and the glue will get stuck inside the bottle. Edit: Super Glue (cyanoacrylate) hardens when it comes into contact with water. The CA molecules start to line up and stiffen. When it is solid, it has fully lined up and has cured. With the cap on the bottle, water in the air cannot get to the glue and it can't cure. If you leave the cap off, it will get into contact with water vapor and garden inside the bottle.", "Some glues need to \"dry\", some need to \"cure\" (which is typically by letting an alcohol or other solvent evaporate), and epoxies need to be mixed with an activating agent (that is they are two parts that set up only when mixed, but usually don't need to give up anything like water or alcohol). If you've ever tried to get the top off of a glue bottle that has been glued shut by accident then you know that glue does, indeed, stick to the bottle. The bottles _are_ chosen for being hard to glue shut using the glue that it contains. For instance \"white\" and \"wood\" glues require pores to work well, so smooth plastic will tend to shed the dried glue easily because the glue cannot \"grab it\" well. So one of the main difference between glues that some are \"filling glues\" and some are \"contact cements\". A white glue is a filling glue. It works by filling the tiny gaps and pores in each of the surfaces and then \"sticking to itself\". White glue basically forms a puzzle piece that is locked into the irregularities the two or more parts being glued. This is why you can let it dry on your hand and peel it off to find a mold of your hand print. If you let that harden fully it becomes quite strong. Basically the body of the glue is \"structural\". Various \"super glues\" are exactly the opposite. They can't stick to themselves well. If you let a drop of it try out the result is brittle and easily broken or shattered. So you want to use as little as possible when you use superglue. If you let a layer build up the joint will not hold. But it works well on \"smooth and hard surfaces\". So it's good for things like sticking glass to metal. It still relies somewhat on microscopic irregularities, but the more perfect the match between the surfaces the better the glue works because it's stronger for being in close contact with both sides of the joint. So glue is fascinating stuff, and picking the right glue is a skill, but lots of glues will work \"well enough\" where \"the right glue\" could have been superb.", "It either needs water to evaporate from it or air to become solid. In the bottle, it doesn't touch open air so none of these can happen."], "text_urls": [[], [], []], "score": [127, 13, 3]}}, {"q_id": "6j5ash", "category": "Repost", "title": "How does Stephen Hawking's speaking software work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djbmsje"], "text": ["Why not let Stephen tell you himself? URL_0"], "text_urls": [["http://www.hawking.org.uk/the-computer.html"]], "score": [8]}}, {"q_id": "6j62k1", "category": "Repost", "title": "Why are things blurry underwater?", "title_urls": {"url": []}, "selftext": "How are the eyes of marine life different? How does a thin layer of air (goggles) make everything suddenly clear again?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djc1q9h"], "text": ["Eyes evolved in the water and in fact when the first creatures went from sea to land in evolution they couldn't see very well because their eyes were not adapted for air. Light tends to bend and refract as it transitions from one substance to another, for instance from air to water and back. This changes the focal point of the light. When water covers the eye it changes the angle the light enters the eye causing a loss of focus. When you wear goggles though they don't let the water touch the eye and so the light isn't bent as it enters and we see clearly. If we still had marine eyesight we would need to wear a mask filled with water in order to see clearly in air."], "text_urls": [[]], "score": [3]}}, {"q_id": "6j6gdv", "category": "Repost", "title": "Why Do We Have Squatter's Rights?", "title_urls": {"url": []}, "selftext": "What is the argument for them? I've never heard them mentioned in a positive tone. Also, what exactly does the term \"Squatter's Rights\" entail? Edit: There were a lot of really interesting and helpful explanation, arguments, etc. This has been interesting and enlightening, thank you!", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djbzn7n", "djbypzq", "djbxp8o", "djc85ur", "djbyssg", "djcsyje", "djcb5z0", "djc9o6u"], "text": ["Everyone's explaining adverse possession but, honestly, *that almost never happens* outside of small chunks at the edge of adjacent properties and, let's be honest, you're not going to call your neighbor a \"squatter\" because a fence got built a foot on the wrong side of a property line. What most people mean when they talk about \"squatters rights\" negatively is the difficulty in kicking out squatters (trespassers) from abandonned property you own. We're not talking about them being there for years and having a legal claim to ownership, just them there a month or two & resisting eviction. Ultimately, this is an extension of *tenants rights*. Now, if you're renting a place & the owner wants you out, they need to go to court and **evict** you by proving you've somehow violated our lease & need to GTFO. Because there's a large disparity in power between the involved parties, legally, the tenant gets to stay until the issue is resolved. People who break into abandoned properties, can use this principle to their advantage. If the cops show up to kick them out for trespassing, all they need to do is provide a minimal amount of evidence that they *might* be legal tenants, and they can stay on the property until a full legal eviction proceeding has taken place. We're not talking about people who've spent *years* on an abandoned property and own it, we're talking people who have been there weeks/months using legal loopholes to avoid getting trespassed. It's not really a legally defined right, just a side-effect of protecting legal tenants.", "First, the problem there is not the squatters rights. The problem is the claim of an oral contract. Imagine if the shoe was on the other foot: The soldier is living in the house, and then some random guy (RG) shows up with a deed, claiming the deed is dated before the soldier's deed and gives RG the right to live there instead. Should the police throw the soldier out before the deed issue is settled? Second, we have squatters rights because sometimes people buy land and don't use it. Or buy land and lose it in the shuffle of deaths and wills and sales so the land ends up wasted. This was especially problematic in old England, where the rule comes from, since people would buy huge tracts of land and it was hard to know where one property began and another ended. The idea was that, by allowing people to take possession of the land by use, you encouraged landowners to actually check on their land from time to time, and also prevented the descendants of an absentee landowner from swooping in 100 years later and kicking you out of your house. It also relates to how the law works. There's a statute of limitations on the action you take to evict someone. (another thing that made sense in the past when paper records got lost or were stolen or forged). You can't even begin to have \"squatter's rights\" to property until that period lapses, and it's usually 15, 20, or 30 years. Last, in most places squatters rights are really hard to get, even if you wait out the time. So, for instance, if you are there with permission, you can't get squatter's rights. And, in a lot of places, if you're there illegally (meaning you just moved in rather than, say, got confused about where the property line was between your house and the next guy's house) you can't get squatter's rights no matter what. ___________________________________________________________________ [Source from previous thread]( URL_0 )", "'Squatters rights' means if you're on a property for long enough, even without paying for it, you have some measure of protection against being removed (or claim you do as a defense or justification). You're already there, so you have a 'right' to stay there. It most often applies to rented or empty houses or apartments, but can apply to people staying on private property as well. The squatter often is not ethically, legally or morally correct in saying they have a right to stay on or in the property, and some squatters really abuse it. There are lots of horror stories about often-destructive squatters, sometimes even home invaders, costing legitimate properly lessors or owners a lot of money, sometimes even denying the owner access to their own property. That's why it's usually a highly negative term. However there are laws on the books in many countries, often differing within individual states or provinces, that say \"if you live there long enough and nobody complains, you can legally claim ownership\". Mexico for example has a 5-year law of this sort. It likely exists because it's better to have a person that owns and is doing something productive with some land than have that land owned but completely unoccupied while homeless people that could use it aren't allowed to. Sometimes squatters can't simply be immediately and easily removed by legal or government enforcement because there's a process those agencies have to follow that is designed to ensure the request for removal is not just an abusive landlord trying to avoid regulations about tenant removal. And some 'serial squatters' take advantage of loopholes in the law to get free room and board, in the same way some people try and eat for free at restaurants by habitually claiming something was wrong with their meal. (edit: grammar and to complete a missing point in the answer)", "It's a doctrine from English common law and better historians than myself can fill in the blanks, but in its most basic form (in the 1600's), there was still empty land in England and Wales and a rumor went around that if you build a cottage and tended to the land it would belong to you. This morphed over time into something much more rigid, but the underlying philosophy is the same .. If you improve unused land and the true owner doesn't affirmatively reject the visible claim of right, eventually the possessor gains an interest.", "Adverse possession is a legal principle that says if someone lives on or uses a property as though they owned it for a number of years, legal ownership can revert to them. This serves two purposes. First, it encourages landlords to maintain their property...if vagrants are allowed to live in it, they obviously aren't doing a very good job. It is less of right for squatters, and more of a penalty for landlords. Next, it protects those who acquired land informally or in a way they cannot prove. If I had a large property, and I offered a small chunk to a friend on a verbal agreement, years later when I passed away my heirs could not take it back. Beyond that, squatting is illegal and squatters have very few rights. Adverse possession takes a long time, seven years is common, and squatters can be removed from a property at the last minute and have nothing to show for it.", "One thing that hasn't really been covered yet is to look at it from the perspective of the government/law enforcement/the courts, and you'll see where tenant's rights/squatter's rights come from. You have two parties to a dispute over property. One side says that they are the landowner and nobody should live there; the other side says they are tenants and are legally residents. A court is going to have to decide who is right and who can prove what they've claimed. Before the court can see the evidence, something has to be done with the property. Both sides can't get their way. So the law has decided that the least bad thing to do in that situation is to allow the people claiming tenancy to remain there. Yes, it denies the owner use of the property until the court rules, but that is considered less bad than throwing someone out of their residence. This decision to protect legal tenants from getting thrown out by malicious property owners has the side effect of protecting illegal squatters from getting easily tossed out.", "Without going into the technical details of the law here is an argument why squatters can be a positive contribution to society. I'll compare it to a car dealership to make it more clear. Car dealers own a building in which they store cars but sometimes they will park a car on a public parking spot. Parking a car there is completly legal and it is OK if there are enough parking spots. Now if a cardealer thinks he can save money on his building and park all his cars on public parking spots then this would push people that actually use parking spots for the intended purpose out. This is not fair but also kind of legal. To avoid this certain rules apply to parking spaces to ensure it's real inteded purpose (providing people with a parking spot) is served instead of the superficial purpose (parking a car). In a city buildings are the cars and the owners the car dealers. The inteded purpose of a city is creating a living and working environment. Things happening in the city should contribute to this, at least to an extend. If someone buys a lot of properties and leaves them unused the inteded purpose of a city is not served so there are rules in place to avoid this from happening. This is done by giving squatters some rights which forces people to take action to avoid there properties from becomming squats, like renting them out. By doing this the inteded purpose of a city is being served again. So optimally there are no squatters because people avoid there properties from becoming squats. Thus giving squatters rights benefit the middle class people way more than the squatters themselves. This is something often not realised by people who are strongly against squatter rights. They themselves gain from these rights by a more liveable city.", "If we're talking about adverse possession, the thing you have to remember is just how extreme the level of neglect you have to exhibit for this to happen to you. Essentially you have to go between 5 and 10 years without even bothering to show up at your property one single time. If you rock up once and there's no evidence of someone living there the clock on adverse possession reset to zero. Literally show up once in five years and take some photos of your empty house so you can prove it wasn't occupied. Send an agent even."], "text_urls": [[], ["https://redd.it/23wiq6"], [], [], [], [], [], []], "score": [843, 200, 27, 12, 7, 7, 7, 5]}}, {"q_id": "6j77po", "category": "Repost", "title": "what's the hazard of drinking aspartame based diet drinks?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djc3px3", "djc4095", "djc58mp"], "text": ["You might get annoyed by people stupidly telling you they are unhealthier than the original sugary drink.", "Nothing. Studies upon studies have been done. It pops up about once every few years. You can thank 90's spam email for originating this beauty.", "Yeah i read on URL_0 that there is no link between cancer and aspartame. so i was wondering why do so many people believe this, still?"], "text_urls": [[], [], ["cancer.org"]], "score": [4, 4, 3]}}, {"q_id": "6j825e", "category": "Repost", "title": "How do Sin, Cos and Tan work? Where are they derived from?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djc8ndt", "djccay6"], "text": ["Imagine the unit circle: [a circle with radius 1]( URL_0 ). If you mark out an angle x at (0,0) and draw a line at that angle the point where it intersects the circle is at (sinx,cosx). Sinx describes the height of the point, cosx describes the length like the image shows. Tanx would then be the length of the line that starts at (1,0) and goes up until it reaches the first line.", "Alright, since half of these answers are about explaining the theory behind sin, cos, and tan, I'll explain the programming behind it. In mathematics, there exists a representation of a function known as a Taylor series, which is an infinite sums of terms that are calculated from the values of the function's derivatives at a single point. Or to simply put it, it's a method that returns a value of varied accuracy. So how would you put it on paper? > Sin (x) = (x/1!) \u2013 (x^3 /3!) + (x^5 /5!) - (x^7 /7!) + \u2026 x! denotes factorial (the product of an integer and all the integers below it. For example 5! = 5 * 4 * 3 * 2 * 1) So let's do sin of 30 (degrees) together: First, we convert degrees to radians by dividing degrees by 180 and then multiplying by pi. > radians = 30 / 180 * pi > = 0.523598776 Now we insert the answer above into our equation. > Sin (x) = radians\u2013 ( ( radians^3 ) /3!) + ( (radians^5 ) /5!) - ( (radians^7 ) /7!) > = 0.523598776 - 0.02392459626 + 3.279*10^-3 ... approaching zero > = 0.49999999135088125 We did it Reddit!"], "text_urls": [["https://upload.wikimedia.org/wikipedia/commons/thumb/8/8f/Unit_circle.svg/1200px-Unit_circle.svg.png"], []], "score": [7, 4]}}, {"q_id": "6jaww5", "category": "Repost", "title": "if all us paper money is legal tender for all debt, how can a store refuse any bills over $10 as payment?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djcv67p", "djcw17y", "djczv6i"], "text": ["When you buy something in a store there is usually no debt involved. You don't owe the store money because you don't own the items you want to buy yet. Since there's no debt, the concept of legal tender doesn't apply and they are free to accept or deny any type of payment they wish.", "When you purchase an item in a store, there is no \"debt\", because you don't own the item until *after* you pay. But more importantly, the words on paper money is not law. There is no federal law in the US that requires private business to accept US currency as payment, or to accept all forms of US currency.", "Well what they are really saying is that \"If you choose to pay with a $50, we may require you to wait here for up to 24 hours until we have a chance to go to the bank and get you some change, as we don't keep that much cash on hand (to prevent robberies) so we'll get it to you as quickly or as slowly as we choose to\" So if you want to stand there for 12 hours waiting on your change, they'll take it, but no one ever would want to do that."], "text_urls": [[], [], []], "score": [18, 4, 3]}}, {"q_id": "6jbk7w", "category": "Repost", "title": "If U.S. Currency isn't backed by anything, how does it hold any value?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djd0fd1"], "text": ["because we all agree it has value. at this point, no currency is backed by anything. not a single currency still in use that is backed by gold or anything tangible. They exist on the credibility of their govt and society. Its convenient to have an intangible unit of trade, and as long as you have critical mass of people that agree to a common unit, it works."], "text_urls": [[]], "score": [5]}}, {"q_id": "6jdmll", "category": "Repost", "title": "How do some fireworks makes shapes and whatnot when they explode?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djdhe7n"], "text": ["Imagine you draw a bunch of dots pretty close to each other on the surface of a deflated balloon. Then blow it up. The dots are much bigger and farther apart."], "text_urls": [[]], "score": [7]}}, {"q_id": "6jflx3", "category": "Repost", "title": "Why is the American flag printed backwards on military uniforms?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djdv55h", "djdzpij", "djdv07i", "djdv2qg", "djebgfx", "dje6nf3", "dje3rza", "dje2y4y", "djeb1im", "dje58z2", "dje1al0", "djdv1ue", "dje3i2y", "dje3o7b", "dje7lkf", "djebe8k", "djefymx", "dje24l0", "dje6an9", "djed045", "djeffn0", "djeir1a", "djefype", "dje956f", "dje6z1v", "djeakb6", "djeh4jz", "djem8cd", "djeecxi", "djefqu5", "dje3t9l"], "text": ["The stars lead the assault. If you were to grab a flag and run with it on a staff it would look exactly as it does on the uniform.", "The [Flag code]( URL_0 ) dictates that the blue field should be upper left. > \u00a7175. (i) When displayed either horizontally or vertically against a wall, the union should be uppermost and to the flag's own right, that is, to the observer's left. When displayed in a window, the flag should be displayed in the same way, with the union or blue field to the left of the observer in the street. On the other hand, [Army Regulations]( URL_1 ) say it should be reversed, to \"give the effect of the flag flying in the breeze as the wearer moves forward.\" > AR 670\u20131, 28018 c (2): The full-color U.S. flag cloth replica is worn so that the star field faces forward, or to the flag\u2019s own right. When worn in this manner, the flag is facing to the observer\u2019s right, and gives the effect of the flag flying in the breeze as the wearer moves forward. The appropriate replica for the right shoulder sleeve is identified as the reverse side flag. TL;DR: to look like you're carrying a real flag as you move.", "It's not. US flags don't have a front and back, rather we are accustomed (by heraldry tradition) to viewing them as though the pole is on the left. The flag is always worn so as to be advancing, or carried forward, on modern uniforms. Hence the blue field is toward the wearer's front. On certain uniforms, like USAF flight suits, the flag is worn on the left sleeve and thus is sewn as you're used to seeing. It was not always this way. On D-Day, the flag on the right shoulder sleeve of US Army uniforms was depicted \"normally.\" This was reprised in the 2016 Army uniform for the Army-Navy game, which featured such a flag (complete with 48 stars as I recall) on the right shoulder.", "\"The reason has to do with proper display of the flag. The blue field of stars should always be in the highest position of honor. When viewing the flag on a wall, the highest position of honor is the upper left when displayed horizontally, and at the top (upper left) when displayed vertically. When displayed on a \"moving object\" like a person or vehicle, the highest position of honor is the front, and not the rear; so the field of blue should be displayed to the front.\" [Source]( URL_0 )", "The rule is: If it moves (like a person, vehicle, ship etc.) The blue field should be facing the direction of movement, to simulate what a flag on a pole being carried would look like. If the flag does not move ( a wall, a poster etc.) The field should be on the upper left.", "Would be nice if visuals were provided for people who don't know what OP is talking about, but still want to learn something new. [\"Backward\" Flag]( URL_0 )", "Some people complained that this post/topic violates the rules of our sub. I think it just barely gets a pass. Partly because it had already gotten some traction and activity. If i had caught it before people invested their time and interest I might have removed it under rule #7 or rule #2. **Edit:** I moved my original comment [here]( URL_2 ). I want to leave a record of it for accountability or context. The only people that it was useful to or aimed at would have seen it by now, so it isn't useful anymore. A line-by-line breakdown i tried to write for someone is [here]( URL_1 ). And my overall thoughts on the whole thing [here]( URL_0 ). I just can't respond to everyone so i thought i'd try to have a central place to direct a few people to.", "Always advancing. Never retreating. If you are carrying a flag and move forward the patch is displayed hie the carried flag would look.", "Moving forward will cause the wind to blow the flag back so that the stars are up front. Look [here] ( URL_0 ) or [also here] ( URL_1 ).", "The wearer is the flagpole, so whenever it's on the right sleeve it'll fly backwards because the wind would be blowing the far right side to the left E: this is how you should actually explain something to a five-year old, preferably with arm-pumping pretending to charge into battle action", "It is to signify forward momentum whether that be on the battlefield or elsewhere. Source: I'm an Army combat veteran", "It's so that it appears that the breeze is blowing the flag back while the wearer is moving forward.", "When you attach the flag to a flag pole, you put the stars nearest the pole. If you were to then carry this pole forward, you'd observe the stars forward with the stripes trailing behind. When you make the flag into a patch, you need a left-side and a right-side version in order to give the picture of the stars forward with the stripes behind.", "Actually looked this up about a month ago. A very watered down reasoning is that it's supposed to look like a free flying flag being carried into battle.", "When the flag moves forward the stars lead. In the face of battle we always advance, because lets face it, these colors never run brother.", "Why didn't they just put it on the other sleeve where it wouldn't have been backward?", "I find the interesting OMISSION from all of the responses is the answer to why it needs to be on the RIGHT arm to begin with. It wasn't always, it isn't in other branches (USAF) and there doesn't seem to be a readily available answer as to why the flag was swapped to the right shoulder, requiring it to be reversed, to begin with.", "The flag on our uniforms it that way to symbolize running towards the battle. I'm a army veteran OEF/OIR.", "It's so that when I run into the Class Six the flag looks like it's blowing backwards in the wind.", "I always wondered so I asked this question to a cop in philly. He said imagine the flag was mounted to a pole, and the person at the bottom of the pole is always charging forward. So only when it's on the right side of a uniform is the orientation flipped. I have a team USA baseball jersey and hat and for the longest time I was pissed cause I thought the manufacturers fucked up lol. I was actually wearing the hat when I asked the cop. Source: just trust me", "Plot twist: The backwards flag represents another country to which the entire military belong.", "If you had two little American flags poking up from your shoulders and you were running forward, what would those flags look like? There you go.", "In less than 24 hours I've seen four videos, and this post, all related to the flag being backwards on military uniforms. The fuck is going on?", "There's a couple reasons really. I imagine you're talking about this: URL_0 First, every flag has two sides, this isn't something that initially occurred to me as a Canadian because my flag is symmetrical, so no matter which direction I view it from, it always looks the same. But for the American flag which isn't, you may see the stars on the left side of the flag, only to see them on the right when win changes direction, like this: URL_1 Furthermore as other people said, the 'backwards' print makes it seem as if the soldier is 'running into battle' with the flag, as opposed to away from it. What you're probably not realizing is that on the other shoulder, the flag is the 'right' way. Like this: URL_2", "On uniforms it appears backwards because they want to convey the look that they are moving forward and the wind is blowing the flag back. It comes from the \"never retreat\" mentality and that they will also push forward towards the enemy", "IT's not... It's printed the correct way. It's supposed to look like a flag does when attached to any moving object which is not the same as a stationary flag pole.", "Like Mel Gibson in the patriot....when you run with the flag...charge the attack...it looks like that. Stars first. Bugged me til i was in the army and someone explained it. Pretty cool when you find out why they have it that way. It's not really common knowledge.", "The real question is, why is it on the right arm?", "The reason is because the flag appears to be waving in the wind, as if it were rushing forward through the air. Back during the time of the American Revolution, militaries around the world still had people carrying flags into battle, rushing forward with the front lines, and the flags on our military uniforms are meant to represent that forward progress, literally and figuratively.", "When I was in military academy I asked my TAC officer, a retired Delta Force sniper, the same question. His response? \"Son because the flag flys in that direction when we charge and move forward. It represents that value and the idea that we don't retreat. It's almost and inspirational reminder that when we want to sometimes go backwards, we must keep marching onwards.\"", "The American flag has to always be pointing forward, so when you see it on a pole the stars are pointing forward. When you see it on a soldiers arm the stars are pointing forward towards the enemy(backwards in your mind). If it in reverse it would look like the flag is retreating rather than moving forward . Pointless fact I know and don't know how I obtained it"], "text_urls": [[], ["http://www.usflag.org/uscode36.html#175", "https://www.army.mil/e2/rv5_downloads/symbols/r670_1.pdf"], [], ["https://www.marlowwhite.com/faq/f-why-is-the-flag-patch-reversed.html"], [], ["http://blog.cvsflags.com/wp-content/uploads/2012/05/dadads.jpg"], ["https://www.reddit.com/r/explainlikeimfive/comments/6jflx3/eli5_why_is_the_american_flag_printed_backwards/djf9a72/", "https://www.reddit.com/r/explainlikeimfive/comments/6jflx3/eli5_why_is_the_american_flag_printed_backwards/dje72a8/", "https://www.reddit.com/r/explainlikeimfive/comments/6jflx3/eli5_why_is_the_american_flag_printed_backwards/djf76zl/"], [], ["http://www.iwojima.com/raising/Slide18.jpg", "http://www.standard.net/image/2015/05/23/800x_a16-9_b0_q80_p1/RL-052015-Print-Run-For-The-Wounded-4.jpg"], [], [], [], [], [], [], [], [], [], [], [], [], [], [], ["https://www.collinsflags.com/blog/wp-content/uploads/2012/05/dadads.jpg", "http://img03.deviantart.net/0be2/i/2015/121/e/f/american_flag_flapping_in_wind_by_houstonryan-d2tkqng.jpg", "http://st.depositphotos.com/1667271/2574/i/950/depositphotos_25748283-Focus-on-american-flag-on-USAF-uniform-of-person.jpg"], [], [], [], [], [], [], []], "score": [11644, 7855, 1356, 1312, 883, 749, 562, 491, 107, 62, 39, 36, 28, 23, 16, 15, 13, 12, 11, 11, 6, 6, 6, 6, 5, 4, 4, 3, 3, 3, 3]}}, {"q_id": "6jg2a0", "category": "Repost", "title": "Why is it so hard for games to be cross-platform? Is it just the fact that companies don't want to work together?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djdyx1f"], "text": ["Pretty much, yes. Each company has their own online account system which does various things, so a developer who wants to do cross-platform play has some work to do bridging those different services so they work together. But that's not *that* difficult. The main problem is that Sony is holding it back. They see PSN as a \"walled garden\" which protects its user from harassment, inappropriate content, inappropriate behaviour, etc. So if they allow games to also play against Xbox Live users, they're no longer in control and can't guarantee users are \"safe\". That's what they say anyway, they have allowed cross platform play with PC before. So their real reason might be something different."], "text_urls": [[]], "score": [6]}}, {"q_id": "6jg3x5", "category": "Repost", "title": "Why do we see people wrapped in blankets in shows/movies after cops arrive at a crime scene; even when in the warmth of their own home?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djdz38h"], "text": ["One of the first treatments for shock is keeping the patient warm. However, in visual media it is more about telling the story. Being wrapped in a blanket shows the viewer that the character is safe now, because being wrapped in blankets is a cozy good thing. This is also why horror movies like to show people being attacked in bed. It up ends the notion that blankets are a safe place, which adds to the fear."], "text_urls": [[]], "score": [7]}}, {"q_id": "6jg7tm", "category": "Repost", "title": "How come we can \"feel\" other people staring at us?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djdzna1"], "text": ["We can't. However, there's an evolutionary advantage to being vigilant, and being wary of being watched. So many little clues will make you feel like you're being watched: A subtle change in the ambient sound quality implying that someone is behind you, and small moving reflection, etc. If you look around and don't see anybody, you mostly forget that it even happened. But if you look around and see someone looking at you, your brain is all, \"Aha! I knew it! I'm _always_ right when I think someone's watching me!\" This is known as \"confirmation bias\"."], "text_urls": [[]], "score": [3]}}, {"q_id": "6jgiuc", "category": "Repost", "title": "How do fighter pilots know that another fighter jet has a missile lock on them?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dje24kz"], "text": ["An electronically steered radar will generally scan a large area of the sky until it acquires a target. Once that happens, it's likely to start scanning a smaller area around the target, both to pick up any movement sooner and to get better sensitivity. This would be easy to detect by the target since the signal would get much stronger and/or it would repeat faster.. FOR EXAMPLE If you're escaping from prison and the spotlights are scanning around, looking for you, you're safe. Once they stop scanning around and just point right at you, they're \"locked on\"."], "text_urls": [[]], "score": [22]}}, {"q_id": "6jinvp", "category": "Repost", "title": "The whole \"mining\" thing with RX video cards?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djeloap"], "text": ["Crypto currency \"mining\" is basically solving a bunch of complex math problems, in exchange you get some of that crypto currency. It just so happens that Radeon graphics cards, specify the newer RX ones, are very good at it. GPU's are better in general at this than CPU's and Radeon based graphics cards are better at it than Nvidia based graphics card. This caused a very high demand for these graphics cards, as the price if Bitcoin and a few other crypto currencies have increased very quickly in the last several months. Many people are buying Radon RX series graphics cards to get in on the increase in crypto currency maker value."], "text_urls": [[]], "score": [7]}}, {"q_id": "6jjpz4", "category": "Repost", "title": "How can aircraft detect when their heat signature has been locked onto?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djerlv3", "djer84l"], "text": ["They can't really detect if someone locks on through the heat signature. However, what you've seen in the movies and possibly from pictures of military cockpits seem to contradict me, right? Well, what's used to detect if someone is \"painting\" you, is radar. If someone is directing a radar signal at your plane, that can be detected with a \"simple\" antenna and some basic electronic circuitry. The strength of the signal will indicate how close the other plane is, and the time between each signal will indicate what's going on. A \"slow\" signal indicates that the other plane is seeking, and faster one indicates that it has \"locked on\" and is tracking. A much faster signal indicates that a radar-guided missile has been launched and is tracking you. Some planes have several antennas all around the aircraft, and can tell the pilot or RIO from which direction the threat is coming.", "They can't detect that directly, because \"locking on\" is an invisible internal decision of a missile or other aircraft. They can infer that something is following them if they see it via radar, cameras, or external warnings (someone else telling them about it)."], "text_urls": [[], []], "score": [15, 3]}}, {"q_id": "6jn4ip", "category": "Repost", "title": "Why do household fans always have the highest option as the first option when you turn it on instead of the lowest option?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djfh83v"], "text": ["It takes a lot more power to start something moving than it does to keep something moving. The highest option is first because it gives the burst of power to start turning the previously stationary fan motor. Once the fan has started, you need much less power to keep the motor spinning so you can turn it down to a lower setting."], "text_urls": [[]], "score": [3]}}, {"q_id": "6jpsme", "category": "Repost", "title": "I've noticed that a lot of antidepressants carry warnings that they may actually cause depression. How do these drugs work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djg3wdw", "djg47yy", "djg4ck2", "djg3zf3"], "text": ["Antidepressants have two functions: to make you more motivated and to actually make you feel less depressed. Unfortunately, the \"less depressed\" part can sometimes take a week or two longer to kick in than the \"more motivated\" part. So that leaves some people still feeling depressed, but more motivated to do something about it... I'm just going to leave this here: National Suicide Prevention Lifeline Call 1-800-273-8255 Available 24 hours everyday", "The actual answer to \"how these drugs work\" is a bit interesting. An executive summary: 1. Drug blocks the pump that pulls serotonin from gaps between brain cells (synapses.) More serotonin remains there, where it can be active, rather than hanging out in the cell. 2. Patients keep taking drug for several weeks. 3. ??? 4. On average, greater improvement in clinical depression after several weeks, compared to people taking a sugar pill. That third step is the tricky part. We know that the drugs hit their targets quickly but take weeks to work, and that they don't do much of anything to mood in healthy people. This suggests that rather than it being a simple matter of serotonin up=good, there's some secondary or \"downstream\" effect of consistently elevating serotonin in those gaps. They don't work as consistently as we'd like, and at present the only way to find one that works is trial and error. (There are efforts to improve this, but it's hard.) The flip side is that when fiddling with brain systems that affect mood, worsened depression is a risk. In this case, it's not a large one.", "Not so sure if this would be an answer to your question but an experience with Wellbutrin I had. It is an anti depressant but also used to help stop smoking. I was never depressed but got on the Wellbutrin to help me quit smoking, within one week I was having suicidal thoughts and learned what true depression was like. Maybe if someone is not experiencing true depression and takes an anti- depressant it can cause a rebound effect and make the person feel depressed. Not a pharmacist, so can't say that for sure.", "Antidepressants of the SSRI (selective serotonin reuptake inhibitor) class work by preventing the outflow of a neurotransmitter known as serotonin from the nerve synapses. This eventually leads to increased quantity of serotonin and leads to \"happiness\". However, for people who are already suicidal, antidepressants in the early few weeks give them enough energy to stop sulking and now they might actually try to commit suicide. This is the warning that it may cause suicidal ideation. As far as the depression warning goes, it's not fully understood but it might mean that a different class of antidepressants is required for the patient if they are feeling more depressed [after prolonged therapy] Edit [ ] Edit 2: do not take more than the prescribed dose of an SSRI to speed up to the \"happy\" part. It leads to heart problems (prolonged q-t wave) and can also cause too much serotonin (serotonin storm) which is fatal"], "text_urls": [[], [], [], []], "score": [9, 7, 3, 3]}}, {"q_id": "6jq94i", "category": "Repost", "title": "why do ceiling fans and many larger fans starts off on high setting and adjusting it sets it down?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djg7c6r"], "text": ["It takes a fair amount of power to get a fan spinning from a full stop. Motors can be damaged if they're running but unable to get the axle to spin. By starting on the highest power setting, they ensure that the motor has enough power when it's turned on to start the fan spinning, and thus avoid damaging the motor."], "text_urls": [[]], "score": [3]}}, {"q_id": "6jqits", "category": "Repost", "title": "What actually happens when you get the feeling of your heart \"sinking\"?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djgb37y", "djgcopm", "djgdf48"], "text": ["Scientists aren't really sure WHY it happens but the feeling you get is your muscles contracting/flexing. Almost like a muscle spasm. Edit: word", "1. It's a mistake to believe that having an emotional response is at all removed from your physical hardware. 2. Emotional responses, besides being integral to your physical functioning, are massively influential on your psychological *perception* of your physical hardware. I mean, you're asking for a wikipedia entry on the phenomenon some humans call \"heart sinking,\" but it's just not available. But that stuff about your emotions absolutely affecting all manner of physical perception of your environment and body? Yeah, that's an important one. That sinking feeling you had was accompanied by an audio/visual filter that's equally hard to describe in scientific terminology. We don't have the tools to observe these events in that way yet. But we sure as hell know that emotions affect us physically.", "I asked this question recently in my abnormal behavior psych class. My teacher explained that the consensus is that it is a result of your sympathetic nervous system overreacting to present stressor triggering a flight or fight like response. (I'm assuming the rapid vasodilation could result in a short drop in blood pressure giving you that sinking feeling but also just a guess) Unless you're talking about when it happens with no external or internal stimuli (a jump scare in a movie or a stressful thought) often described as \"heart skipping a beat\" could potentially be a heart abnormality causing a murmur and should probably be consulted with a proper physician"], "text_urls": [[], [], []], "score": [9, 7, 6]}}, {"q_id": "6jql0v", "category": "Repost", "title": "if our resting internal body temperature is around 98 degrees, why do we prefer temperatures lower than this?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djg9vqw"], "text": ["Because the human body is always producing heat, like a light bulb. More when a person is active and less when at rest, or sleeping. But the body is always cooling itself. It is much harder to cool yourself when outside temperature is equal to the internal temperature."], "text_urls": [[]], "score": [3]}}, {"q_id": "6jrcqo", "category": "Repost", "title": "when in a quiet room why do ears start to ring?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djgf2zz"], "text": ["To the first part - only in a very quiet room can normal people (who do not suffer from tinnitus) can hear this ringing, which is just the flow of your blood through the blood vessels in your ears. To the second part - I'd say that after a period of being in a quiet environment, your eyes adjust and become more sensitive. Just like a light seems a lot brighter after you've been in a dark room. (Anyone correct me if I'm wrong.)"], "text_urls": [[]], "score": [5]}}, {"q_id": "6jvl9j", "category": "Repost", "title": "Why is it easier to balance something on your finger when it's rotating (like balancing a spinning basketball on your finger) compared to when it is stationary?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djhdmvs"], "text": ["Top comment from march 2015 when this was asked: (answer by u/Toppo) Every object keeps continuing its movement until there is an opposing force preventing that motion. When the basketball is spinning, the spinning is force in motion, which keeps its resisting change to its position. When you put a ball to spin, it attains energy to resist other forces, like gravity pulling it out of balance. If the ball does not spin, it has no force to resist gravity. Also [this video ]( URL_0 ) was posted by u/LinearWave on the same thread"], "text_urls": [["https://www.youtube.com/watch?v=8H98BgRzpOM"]], "score": [6]}}, {"q_id": "6k16sr", "category": "Repost", "title": "What causes \"asparagus pee\" and how does it happen so fast after eating it?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djikcxb", "djiw0ki", "djj2fl1", "djj5xia", "djja4d5", "djjimvn", "djjk5kc", "djjcgz3", "djjskd3", "djjp8de", "djjs4yi"], "text": ["Short answer is that asparagus contains a natural chemical aptly named asparagusic acid. This acid is broken down by the body into sulfur-containing compounds. Those sulfur compounds smell. This is the same reason rotten eggs smell. And once made, the breakdown products end up in your urine. Because they are highly volatile, they make it into the air as you pee, and float on up your nose! I don't know exactly why it shows up so quickly, but my best guess is just that the smelly compounds are made from asparagusic acid very quickly, as soon as you begin digesting the asparagus. Source: URL_0 Not an asparagus expert, nor a pee expert. Just googled your question and found a good article.", "When your digestive system breaks down mercaptan (a compound in asparagus), by-products are released that cause the strange smell. The process is so quick that your urine can develop the distinctive smell within 15 to 30 minutes of eating asparagus. Not everyone suffers this effect; your genetic makeup may determine whether your urine has the odor -- or whether you can actually smell it. Some people can't even smell the odor in asparagus urine!", "**What causes it?** *Enzymes* There's an inheritable gene that some people have that includes a specific enzyme that can break down the acid in asparagus (C4H6O2S2). This acid, when broken down, smells. There is nothing wrong in \"asparagus pee\", as it's not toxic. It simply is unpleasant. When you have the right gene passed on to you, you can either produce or smell this \"Asparagusic acid\". If not: You simply lack a gene modification. Nothing to worry about. **Why does it happen so fast**? Again, Enzymes. They are pretty quick in breaking down the compounds found in asparagus and therefore it smells instantly.", "There are something like 500 genes that contribute to the ability to smell that \"asparagus pee\" smell. Only roughly 50% of people have the necessary genes for it, meaning only about half of all people can smell it. There is some debate to this; some scientists think certain people don't produce the smell itself, however I can say from personal experience that I always smell it, while my wife never smells it, regardless of who is the pee-er. The cause of the distinct smell is sulfur, as the byproduct of the digestion of asparagus is a bunch of sulfur-based chemicals. The chemicals are volatile, which means they have a low vapor point where they can get into the air and therefore be detected by human noses. While they are locked in the asparagus, they are not volatile and so we don't smell them.", "Fun Fact: There are two things at play here, the ability of the body to *produce* the pee smell (one gene) and then there is the ability to *smell* the pee smell, which is a different gene. So you could be producing the smell and not know it, you can also be able to smell it in other's pee, yet not produce it yourself.", "I have the same question about Golden Crisp and/or Honey Smacks cereal. Urine smells like the cereal rather quickly after eating.", "Do you know if you can smell asparagus pee, you are one of the few that have the ability. Just like some people are born with more cones and rods in there eyes that give them super color vision, you have a much stranger superpower of smelling asparagus pee that affects 1/3 of the population.", "Along with the other answers in this thread, vitamin B can also cause rank piss. If you were to take a supplement of B 6, B 12, and others, your urine will gain color even if it is diluted through heavy ingestion of water and will also smell like piss. This is why many people use it to prevent a urine sample being denied during a drug screen. If your vegetable contains a high amount of vitamin B (I believe asparagus, broccoli, and other firm, green veggies do) then prepare for your piss to smell worse than R Kelly's sheets and Trump's comb-over combined.", "More interesting to me, what causes \"Sugar Puffs pee\"?", "What about Sugar Smacks cereal? Those always make your pee smell funny as well.", "Depending on who you ask, it's either aspagusic acid, or methenitheol. Most now believe that pretty much everyone is a smelly \"excreter\" but only 25-33% of the population has the gene that allows them to \"detect\" smelly pee. Source: Alton Brown is my hero, also Google :-)"], "text_urls": [["http://www.smithsonianmag.com/science-nature/why-asparagus-makes-your-urine-smell-49961252/"], [], [], [], [], [], [], [], [], [], []], "score": [4191, 333, 113, 90, 38, 21, 7, 4, 3, 3, 3]}}, {"q_id": "6k2r5e", "category": "Repost", "title": "Why are some hazardous items labeled: \"Known to the state of California to cause cancer, birth defects or reprooductive harm?\" Why is it worded in such a way?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djiux5q", "djiv20o", "djiuzas"], "text": ["In the 80's warning labels were not that common, but consumer concern was rising. So California took a step to inform their citizens, making a list of chemicals known to do x (one of the things listed in prop 65). This list must be updated once a year and has grown to almost 800 items. The list, which is being kept active by California has to have a warning stating that California recognizes y chemical causes x if it is sold in California so that Californians may make informed decisions. If you are out of the state of California and see the warning, you are benefiting from the fact that it is cheaper to do a single label versus a label for California and a label for other areas.", "california has some of the most aggressive consumer and environmental protections, and they are also one of the largest markets in the world. california pursues some of these issues much more than the feds or other states, and so companies word their disclaimers to comply with their laws because you're going to tailor your products and packaging to comply with regulations in one of the biggest markets in the world.", "California has legislation requiring labeling of certain materials on products sold in its state. Because it's cheaper and easier to produce a single package for the entire U.S. market than create something different for every state, they print it so that it will be legal if that particular box ends up in California. It's the same reason you see refund information on glass bottles for a bunch of different states instead of just the state you're in."], "text_urls": [[], [], []], "score": [8, 5, 3]}}, {"q_id": "6k46dw", "category": "Repost", "title": "How did the modern version of the globe come to be, with what we call North on the top and Souyh on the bottom?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djj6wsv", "djj7nsu", "djj76fa"], "text": ["In actual fact nobody really is sure as to which side is north and which side is south. In Australia for example, globes can be purchased that are flipped with the southern hemisphere appearing above the northern one. I believe the reason most globes are the way they are today is largely down to the British empire and the richness of explorers and adventures from the northern hemisphere earlier in human history.", "It was an arbitrary convention that was adopted by the ancient Greeks. From there it spread to Europe and then the Europeans conquered everybody else. There is no inherent difference between north and south. The choice of which one to make \"up\" is purely a matter of convention.", "If you're a primitive civilization you need a way of telling people what directions things are in (what direction is home). Ultimately, you end up using the sun, since it's easy to figure out. Thus you end up with \"the direction the sun rises\", \"the direction the sun sets\", \"left of the direction the sun rises\", and \"right of the direction the sun sets\". The cardinal directions mostly stem from these directions and definitions. As for why North is up, well once you understand the earth, it's clear that North/south are the points that don't move, they are the directions you can look and see a star never moving year round. They are both great candidates for \"up\", but if you live in the northern hemisphere, you can see the north star, if you live in the southern hemisphere you have the southern cross and can easily identify the pole in the sky and you can't see the north star. Thus, for almost everywhere on earth, you can see exactly one pole spot in the night sky. That means that likely if you were to pick, you'd pick the pole you can see that is physically up (North for the northern hemisphere, south for the southern hemisphere). When it came to deciding what one is up, everyone agreed North is up in Europe, and everyone in China said south is up. Europe one that argument."], "text_urls": [[], [], []], "score": [6, 3, 3]}}, {"q_id": "6k54qs", "category": "Repost", "title": "Why do retail stores sell things at $.99 $.98 and even $.97 instead of $1.00?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djjehei", "djjebqr"], "text": ["$1 is a psychological barrier for a tremendous number of people. I worked at Pillsbury a long time ago. Every time they tried to raise the price of Totino's Pizza from $0.99 to $1.09, sales would tank. So they just kept cost-reducing the pizza instead--mostly by making it smaller.", "It comes down to how we as people digest information. End of the day if you can say that you purchased something for one dollar, compared to I bought that for less than a dollar, it sounds better. It's easier to brag to your friends about it as well, which in turn could make them buy said product. It's merely perception and advertising trying to get you to buy into their deal."], "text_urls": [[], []], "score": [5, 3]}}, {"q_id": "6k5lna", "category": "Repost", "title": "Why are we so tired throughout the day but when it's time to sleep we're wide awake?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djjq77i", "djjudj7", "djk3gnr", "djjp9qo", "djk4cmg", "djjna4j"], "text": ["It is caused by bad [sleep hygiene]( URL_1 ) which can just generally throw off your sleep cycles. Essentially, you are over-tired. There is a \"sweet spot\" for everyone regarding the time they should go to bed (just the right level of drowsy). Once you get past that, your brain thinks there must be an important reason for you to continue to stay awake, so it sends you a surge of adrenaline. When you lay down, your body just isn't able to relax that quickly. _________________________________________________________________ [Source from previous thread]( URL_0 )", "Looking at back lit devices at night before bed (I.e. Phone, iPad etc) may cause a 'phase delay' in your sleeping patterns-tricking your brain into thinking it is daytime when it's not. Using artificial light like this can be used by travellers to help get over the effects of jet lag.", "If you're like me, you have [delayed sleep phase syndrome]( URL_0 ). It's incredible to realise that for most people, they are wide awake during the day and sleepy at night.", "Perhaps it's boredom. During the day, most do not have the chance to entertain themselves as they do at home, thus tend to procrastinate and entertain themselves with their leisure time which for most is at night.", "You're probably not doing enough physical exercise every day. I used to have insomnia, but I started swimming every day and now I am able to get to sleep much easier. Also, like others have said, TV and mobile devices, smart phones and tablets are too bright. I turn on the blue light filter and the brightness way down. And generally avoid any bright lights for at least an hour before bed. The best way to fall asleep is to simply read a paper book with a dim reading light with warm light color (more orange than blue). Also, don't consume any caffeine 8 hours before bed time. Personally, I only get caffeine from tea and only during the morning. Coffee has way too much caffeine and so do soda drinks.", "Someone commented on a similar post a while back that we get tired and fall asleep because we aren't trying to sleep, and when we ARE trying to sleep, our brain is working on falling asleep. As such it takes us a while to fall asleep while actively seeking slumber."], "text_urls": [["https://redd.it/257n52", "https://sleepfoundation.org/ask-the-expert/sleep-hygiene"], [], ["https://en.wikipedia.org/wiki/Delayed_sleep_phase_disorder"], [], [], []], "score": [303, 29, 22, 21, 12, 3]}}, {"q_id": "6k6hbr", "category": "Repost", "title": "When we type up an email and hit \"send\", how does the Internet know where to correctly deliver our email? What does this process look like between two computers/email accounts?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djjp2un", "djjoz00"], "text": ["When you hit send, your mail is delivered to the Mailserver of your mail provider. Your computer knows which one that is because it was part of your initial mail setup on your computer. Once the mail reaches 'your' Mailserver it'll look at the domain (the part behind the @ sign in the mail address) and looks up the IP address of that domain using DNS (think of it as the phone book of the internet). Once the server knows the IP of the recipients mailserver it'll send your mail over there. The recipients Mailserver then looks at the account name (the part before the @ sign in the mail address) and puts the mail in the correct mailbox. Edit: the recipients computer is set up to know the recipients Mailserver and thus checks there for new mail. So in the end, the two computers themselves don't communicate directly at all but the servers do.", "It works kind of like the post office. Think of it like this. The stuff after the @ symbol is the city. The stuff before the @ is the street address. When you hit send the email gets given to the post office of the \"city\" you specified which can be google, yahoo, comcast or hotmail. The city then looks at the \"street address\" and figures out where to put it. You then go and pull it out of your mail box."], "text_urls": [[], []], "score": [7, 3]}}, {"q_id": "6k81u3", "category": "Repost", "title": "Why is the sound quality in phone-line hold music so terrible?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djk19cr", "djk4t62"], "text": ["This is related to the bandwidth of the signal. Think of bandwidth as how much information can be sent at any one time. Plain old telephone service (POTS) has a frequency range of 300\u20133300 Hz, or 3000 Hz bandwidth. This is really all that is required to hear and understand a voice clearly (this is called voiceband). If you were to listen to FM radio it will transmit a bandwidth of around 15 kHz. This means this signal is able to carry much more information. This means the sound you hear will likely be clearer, can be sent in stereo (more than one channel) and just overall be of higher quality. There is no reason for the DMV to send a high quality music signal if they are limited in bandwidth using the POTS. It would be like mailing a high quality cake through the postal service in an unprotected box. No matter how nice it was when you sent it the cake would just end up smashed and destroyed when it arrived. Also keep in mind that even if your telephone service has better bandwidth this is not really something the DMV would spend money on or be able to adapt to quickly. They are all about what will accommodate the most people. This reasoning is also why we still have paper registrations or stickers we put on when it could fairly easily be electronic.", "As already explained, a lot of phone lines are working on very old standards and most of them physically cannot support sound efficiently outside of the human speech range. On an electrical level, anything outside of those ranges gets attenuated prematurely. This means that when playing music, all higher and lower-pitched sounds will be 'filtered out'. This also kills harmonics and overall makes the music sound 'flat'. But other factors make it sound terrible and 'irregular'. Most telephone switches use a couple of compression methods to limit packets going through. This is because even though the last stretch of line up to your phone is analog, most 'modern' telephone switches operate digitally, and you only have so much bandwidth in a T1 channel, so not everything goes through. A lot of systems also aren't 'really' two-way and instead alternate very quickly as the conversation goes, even with two people speaking at the same time. You can actually test that for yourself; call some automated reception and start blowing into your handset, most likely the voice on the other side will start cutting out. That compression acts very quickly, and is tailored for human speech, so whenever music stops sounding like someone having a conversation, parts of it starts being filtered out, on top of what doesn't go through the cable in the first place."], "text_urls": [[], []], "score": [25, 7]}}, {"q_id": "6k87x3", "category": "Repost", "title": "Why is sexual abuse so rampant in the Catholic Church? Is it as common in other organized religions?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djk22gk", "djk23le", "djk01hi", "djk2wrk", "djk4dsp", "djk5f7o", "djk581c", "djk5ozp", "djk0wyk", "djk5vr8", "djk2wrm", "djk54nc", "djk55xq", "djk6bei", "djk8aeg"], "text": ["The \"rampant\" thing is a matter of perspective. The catholic church is huge, and centrally organized. Over the years I've heard about lawsuits brought against officiants of other religions as well - along with scout leaders, teachers, boarding schools, etc. What happened with the catholic church was in some cases evil and inexcusable but also, to some extent a product of the time. In the olden days when I was young, people thought that pedophilia was a disorder that you could go for a few weeks of therapy and it would go away. They also thought that letting anyone know their child had been a victim of a sex crime would be permanently damaging to the child whereas the crime itself could be forgotten because children get over these things. So they would send the priest away for therapy (best case, worst case just send him away) and the family wanted it kept quiet so the family didn't call the police either. I mean, if it was me, I wouldn't have called the bishop to report my son was molested, I'd call the police. But back in those days, parents didn't want the world to know their son has anything to do with \"gay\". As far as the rampant thing, I'm on my phone and can't find the statistics among different churches but I heard on the radio a child advocacy group said all religions are about the same on the prevalence of offenses, but the catholic church had a hierarchy that made it possible to move offenders around rather than throwing them out. I grew up in a catholic neighborhood and went to catholic schools, married a catholic, and know of only one person who had an issue but then there are a lot of priests and i think the ones who were bad had lots of victims more than that everyone was bad. The important thing is in being outraged about the Catholics to not let down protection of children just because most abuse isn't by Catholic priests or any other religious group. It comes from everywhere. I've been reading a lot lately about how schools just help to move teachers around who've been accused because with union contracts it's too hard to fire them. Parents seen to be the main abusers, and surprisingly, other children. There are some stats about child sex abuse here: URL_0", "The Catholic Church has a rate of sexual abuse virtually identical to normal society. So the idea that it is rampant is skewed impressions of events. There are many reasons why we see it skewed: 1) They are a position of social power in our lives and so abuse of said power is more notices. It is the same reason we pay attention to teachers and to politicians. 2) Their specific role is suppose to be above sexual things. So violation of their vows of celibacy is seen as being extremely severe. 3) People remember and gossip about bad things.", "Predators seek out positions of power over their victims, and a member of the clergy has a lot of power over people. On top of that the Catholic Church had a history of covering up for their priests and sending them to a new area where the community wouldn't know if their crimes.", "It's not that it's more common in the Catholic Church. That's kind of a misconception based on its prevalence in the media, but I've heard that abuse by priests is no more or less common than abuse by other people in similar positions of authority. The issue and the reason it's so prevalent in the media is that there have been several cases now where bishops and others in higher positions of power in the Catholic Church have taken efforts to cover up the occurrence of abuse, shuffle priests to other dioceses to avoid responsibility, and protect the priests involved in these scandals rather than the families who were victimized.", "I don't know whether the percentage of priests who abuse is greater than that of any other profession where people have authority over children. The reason that the catholic church is so hated for this is the fact that they know about the abuse *and cover it up and protect the priest*. Furthermore, they endanger a new parish by moving the offender in with no warning to parents. In all the documentaries I have seen, the attitudes that are expressed by bishops and cardinals that they are somehow exempt from reporting these *crimes* to the police is the most despicable aspect of their behavior. My opinion: The catholic church has been exposed as an evil and criminal organization. They should lose their tax exempt status in the US.", "So a ton of people seem to have this same misconception about sexual abuse rates and what they see in the media confirming such. Essentially you're being taken advantage of by your own confirmation biases because the only time you ever hear of a Catholic Priest in the news is in a sexual abuse case. From this you think, \"wow this must happen all the time if I see it all over websites what seems to me like ALL the time.\" So once you get that initial idea in your head that \"catholic priests are more inclined to be child molesters\" you continuously feed into that notion by affirming it with more and more news stories. In reality, sexual abuse cases within the Church are no more prevalent than they are in the general population. Here is a blog post by an adjunct professor of psychiatry at Stanford who explains the situation in greater depth. URL_0", "Jehovah's witnesses were recently investigated by the Australian royal commission who [found]( URL_0 ) 1,006 cases of JWs accused of abuse and also that the policies of the JW organization do not adequately protect children. So no, it's not just the Catholics, its any organized religion that lacks transparency and accountability in their leadership. There is a \"handle it ourselves\" mindset in these communities. They have a kind of adversarial relationship with secular authorities. Plus, when you're claiming to be the embodiment of God's will on earth, having sex offenders in your midst doesn't help convincing your followers of that. So basically the needs of the church come before the needs of the children.", "I'm a cradle Catholic who went to Catholics schools from 3rd grade through high school. I was also an altar server through 8th grade. I guess here I should stipulate I was never abused, nor around any priests who gave me any odd vibes. There was a priest at our church, during the time I was a server, who was eventually accused of engaging with a minor (I think some high school kid---can't recall if it is male or female). As far as I know, there was no coverup or anything. But to your questions: Why is it so rampant? Well, I think there are a couple of reasons I can identify: 1) The church has a worldwide, very detailed hierarchy. Whenever there is a lot of organization and red tape, it makes it easier to hide things. And this becomes especially true when this massive hierarchy is a religious one, so people have that factored in. 2) Catholicism has \"confession\" or \"reconciliation\" where sins are confessed to a priest who, by the power given to priests by Jesus (or so we believe), those sins are forgiven. What is said during this time is absolutely private. So if one priest confesses to another priest through this sacrament, it is much less likely that it will be reported, because it \"shouldn't\" be. So basically secrecy and a large organization that can facilitate keeping those secrets. I am not in anyway justifying that. I think it is awful. And generally the Church has taken huge steps to rectify this problem and ensure that abuse doesn't occur, and that it is reported when and if it does. I coached my little brother's Catholic Youth Organization basketball team a few years back and had to have a background check and attend a three hour training session that allows us to recognize and address abuse. There are tip lines and offices assigned to address any allegations, and they're taken very seriously, as they should be. Is it more prevalent in the Catholic Church? No. It isn't. Catholic priests don't offend at a higher rate than other males, and other religions have similar rates. That doesn't justify or excuse anything, of course. I think that, as I discussed above, the reason it feels like it is more common in the Catholic Church is because there is a worldwide hierarchy that systematically hid abuse. So once it was exposed it was overwhelming. Whereas if there are hundreds of little Baptist Churches who are only loosely connected, and abuse is found to have occurred at each, it would be view as a local problem with each church, not a problem with the Baptist faith in general. I guess I ultimately don't view child sex abuse as a \"Catholic\" problem. Sadly, a child is just as likely to get abused by an adult in any other kind of organization (be it youth sports, boy scouts or another religious organization). It is the scale, depth and consistency of the coverup, probably combined with the sometimes-mysterious nature of the 2000+ year old Catholic Church, that ends up making it more newsworthy and more well known than general abuse. I think the danger, though, is that parents might be less likely to be worried about their children or look for signs of abuse because, \"We don't go to Catholic church with those pervert priests.\" Unfortunately, a pastor or scout leader or youth coach is just as likely to be a pervert. So always be vigilant with your children. Edit: I'll also add that more attention is paid to Catholic sex abuse scandals because priests are unmarried and supposed to be celibate. So people want to argue that potentially many are homosexual and/or that celibacy leads to abuse. That's just a massive and dangerous misunderstanding of what drives an abuser. One doesn't start raping children because they are gay or because they aren't otherwise having sex. It is because of an awful mental defect and/or some kind of innate evil.", "just because now Cardinal Pell has been *accused* of sexual abuse * firstly it doesn't mean that he *has been condemned* * secondly it doesn't mean that *sexual abuse is rampant* in the catholic Church some time ago an italian journalist (Introvigne) wrote articles and a brief essay about the argument. you can read it [here]( URL_0 ) translated by google I can copy here briefly the conclusions > To know whether the Catholic Church is a particularly favorable environment for pedophilia - and the priesthood is a \"life-threatening\" state of life - it would be necessary to compare statistics on Catholic priests to those on Protestant pastors, rabbis, imams and school masters. Of state facilities. For all these categories, Jenkins does not give data on accusations collected with the same systematicity as the Catholic priests have been studying; But condemnation data shows that the percentage is similar, and in some cases higher, than the priests of the Catholic Church. For Jenkins, this figure removes, among other things, the repeated repeated thesis that priestly celibacy is responsible for pedophilia. Protestant pastors and school and asylum masters are mostly married, yet there is a proportion of pedophiles who are similar or taller than Catholic priests. As Cardinal Archbishop of Sydney, George Pell (and Jenkins data confirm this), ninety percent of pedophiles are married . Yet - as far as politically correct - the data confirm that the pedophilia risk is greater among homosexuals. While it would be unfair and absurd to argue that all homosexuals are pedophile, it is a fact that many pedophiles are homosexual. According to the John Jay College report, 81% of accused priests with minorities in the 1950-2002 years had a homosexual orientation. However, when Benedict XVI advised American bishops with greater caution before ordering as seminarian priests who show homosexual orientation, the same media - including the BBC - who call for harsh measures against pedophilia risk have accused the Pope of being \"homophobic.\" Where is the mistake? unfortunately, as you can see by other comments, the *general opinion* is that priesthood and celibacy is somewhat *bad*... even if statistically it isn't.", "There is a royal commission into child abuse in Australia right now. What they have found is that child abuse happened pretty much everywhere. Almost any institution that was responsible for looking after children had child abuse. Church's, state institutions, secular, government. They all did it. The rate of child abuse is not too different between any institution. Its just the Catholic Church looked after more children than most, and is one of the largest institutions of its kind in the world. But the rate seemed to be something like 7% of of priests would abuse children (yes the number was that high) and it didn't matter whether they were catholic or something else. The rate was fairly consistent despite different institutions and histories. It seems to be something inherent about people who become priests and are given that responsibility.", "\"The answer lies with the victims. Many, like Mr. Rozzi, are resilient and accomplished. (He is a businessman, a husband and a father, as well as a legislator.) Some are utterly destroyed, unable to hold down a job or romantic relationship. But no matter where they are on this spectrum, the abuse they suffered is often so searing that it is the formative experience of their lives. Even if they have supportive family and friends, a financial cushion and plenty of time in therapy \u2014 all big \u201cifs\u201d \u2014 they never entirely leave it behind.\" \"Of course, child sexual abuse is an issue everywhere, not just in the Catholic Church. But the scandal in the Catholic Church has proved far more extensive, and experts I have spoken with over the years have had a few theories why. One is sheer numbers \u2014 Catholics make up about a quarter of the American population and are the largest single religious denomination. The Catholic Church is also a hierarchical organization that keeps extensive records, so abuse usually leaves a paper trail.\" Another factor, too, is the exalted position of priests, acting \u201cin persona Christi\u201d \u2014 in the person of Christ. Many Catholics, survivors included, have told me they had found it unthinkable that a priest could be capable of crimes against children. And then there is the church\u2019s requirement of celibacy for priests. While many live by and value it, for others it has led to covert sexual relationships with adults, double lives and deep secrets. Some also theorize that the all-male priesthood is a factor. While it\u2019s quite possible that having women in the clergy would have instilled more accountability and sensitivity, child sexual abuse also happens in faiths with married clergy. It also happens in families.\" _____________________________________________________________ [Source]( URL_0 )", "There's a deadly good documentary on Netflix called the keepers. It's quite graphic, but watching it offered some insight on this topic.", "On a practical level, an abuser needs a few things: * Access to children * Trust (People need to allow them to spend time alone with kids) * Authority (To cover up their actions, the kids need to obey their instructions not to talk about it) * The appearance of innocence (An abuser needs a good cover that projects innocence. For example, a 'strange man in the park' will always raise suspicions.) Clergy naturally have the those attributes just by being clergy. Some abusers go to great lengths to access children. So one question would be which came first, the desire to abuse, or the desire to be a member of the clergy?", "The Catholic Church is a centrally organized, hierarchical institution that is perceived as being *complicit* in the assaults--that is the major difference. Whereas when a Baptist minister commits a similar offense, the entire Southern Baptist Convention (which doesn't share the same organizational structure as the Catholic Church) doesn't become complicit by moving the minister or paying hush money and generally aiding & abetting the perpetrator. It *may* also be true that abuse rates amongst priests mirror rates in society at large (this can be debated) but the unique thing about priests is that they have *enjoyed the protection of a world-wide organization that can and does quickly remove them from the jurisdiction in which their crimes were committed.* As others have noted, the Catholic Church has positions of power and influence both within their congregations, but also the community and local and national governments. The Church has exercised this political and \"moral\" influence to the advantage of the offender and to the detriment of victims. Finally, few modern religions require their leadership to be unmarried, celibate and male. I think it should be fairly obvious to any *reasonable* person that those requirements will most certainly result in either drawing in people with sexual issues or creating such issues by denying certain biological imperatives. The Church is implicated insofar as they have refused to change these requirements and create a healthier and more diverse core of leadership not subject to daily sexual frustration and denial.", "*(This answer assumes \"If it isn't any more common in the Catholic Church\" as this part of the question does.)* > If it isn't any more common in the Catholic Church, why is it so much more publicized than other religions? **ELI5: *Everyone knows who a Catholic is, most people have reason to hate Catholics or their bishops, and big scandals about people everyone knows about sell more papers than scandals about someone nobody knows about*.** **Short version:** If Cheney shoots a guy, it's big, national news. If someone identical to him does it who is not a hated national public figure, it's a local story. If it looks like a bunch of people exactly like Cheney do it, with similar political views, similar notoriety, and similar positions in government, it looks like it's endemic, and everyone loves reading about it, even if the ties are more cultural/spiritual than personal. This comparison works because the Pope's role in the active administration of the diocese is actually extremely minimal. To his credit, the Pope who best responded to the sexual abuse crises in recent years is unquestionably Pope Benedict XVI, despite the media narrative that he was enabling the cover-up. See [Marcial Maciel]( URL_1 ) for a specific example, and note that [his involvement in cleaning up the \"filth\" stretched from before he was Pope]( URL_0 ). ------------------------- **Long version:** It should be noted that coverups are also quite common elsewhere. I am not saying that the coverups weren't evil---I am saying that the evil is more common than most people are giving credit. So why the difference in coverage? Yes, other religions don't have a bureaucracy which leaves a paper trail that accounts for up to a million or more people at a time, but mostly it's that readers love consuming news against the Catholic Church, including ex-Catholics and practicing Catholics! There are four big groups involved in consuming media coverage and all of them have something to profit by the news of a scandal. (This will be from the perspective of an American, but the patterns appear to repeat elsewhere.) **Protestants:** The United States is not a Christian nation---it is a Protestant nation, or historically so. Anti-Catholic prejudice runs deep, and the narrative only recently included John Kennedy (reviled by many) and the Bing Crosby-crooner priests. In the first century of the United States, the Papists were seen as the tentacle of Europe, and Catholics were necessarily disloyal to the country because they were subject to a foreign power. Mostly, they were caught up in the \"errors\" of Rome, and Rome herself was pictured in Pilgrim's Progress as an evil giant paired with to paganism. **Irreligious:** From the perspective of the less religious, the Catholic Church is still an international organization toting belief in God. (See Reddit for an example of how gracious many though not all irreligious folks consider anything that has anything to do with religion.) For those less religious who aren't the /r/iamverysmart or /r/Atheism crowd, the talk about the Catholic Church even in this thread is caught up with phrases like \"regressive sexual ethic.\" Anti-abortion, anti-contraception, and in an age when the god of most people is the orgasm? Seeing the Catholics taken down a peg is cathartic. \"I knew something was wrong with them! Obviously it's the celibacy.\" (There's nothing wrong with celibacy; \"If only schoolteachers/scout leaders could get married they wouldn't rape little boys,\" & c.) **ex-Catholics**, especially Protestant converts, resent or even hate the Church more than the irreligious do. Basically, combine the two above for the most potent recipe for resentment and hatred. **Catholics**: Without too much detail, there are significant internal stresses within the Church. From the actually anti-Semitic fringe who are in clear schism, who say that the Second Vatican Council is proof that there have ceased to be valid popes, to those who do believe that there are valid popes but resent the treatment of faithful clergy by wicked bishops, to those who resent the treatment of dissident clergy and \"womenpriests\" by faithful bishops, to those who were curtly talked to in confession once, there are a great number of Catholics who have some personally significant reason to believe that bishops deserve some kind of evil retribution. This is to say nothing of those who hate the Church out of legitimate hatred of the evil done by wicked bishops---but there are many who hated before the news broke and are riding the wave. --------------------- Add up the percentages of the population represented and you get a few percentage points short of everyone. In general, despite internal stresses there is a Catholic presence everywhere in the country and basically everywhere in the world (other than, say, North Korea.) Everyone knows who a Catholic is, and it looks like an international organization rather than a local organization covering a land area rarely larger than a few counties bunched together. It looks like an organisation with deep pockets when it's really hundreds/thousands of local organizations with very little liquidity. Americans hate the rich guy, and Americans love seeing Catholics as evil even when they aren't rich. It should be said that there are many dioceses that never had a child sex abuse cover-up, even in highly Catholic areas. These dioceses were never wealthy enough to have pull or connections."], "text_urls": [["https://www.rainn.org/statistics/children-and-teens"], [], [], [], [], ["https://www.psychologytoday.com/blog/do-the-right-thing/201003/six-important-points-you-dont-hear-about-regarding-clergy-sexual"], ["https://www.childabuseroyalcommission.gov.au/media-centre/media-releases/2016-11/report-into-jehovah\u2019s-witness-organisations-releas"], [], ["https://translate.google.it/translate?sl=it&amp;tl=en&amp;js=y&amp;prev=_t&amp;hl=it&amp;ie=UTF-8&amp;u=http%3A%2F%2Fwww.cesnur.org%2F2007%2Fmi_preti.htm&amp;edit-text=&amp;act=url"], [], ["https://www.nytimes.com/2016/04/20/insider/sex-abuse-and-the-catholic-church-why-is-it-still-a-story.html"], [], [], [], ["https://en.wikipedia.org/wiki/Pope_Benedict_XVI#Sexual_abuse_in_the_Catholic_Church", "https://en.wikipedia.org/wiki/Marcial_Maciel"]], "score": [280, 157, 45, 33, 18, 13, 8, 7, 5, 4, 4, 3, 3, 3, 3]}}, {"q_id": "6k8bpn", "category": "Repost", "title": "How does SPF actually work to block out sun rays?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djk21s6"], "text": ["A sunscreen product acts like a very thin bulletproof vest, stopping the UV photons before they can reach the skin and inflict damage. It contains organic sunscreen molecules(such as avobenzone or oxybenzone. Instead of physically deflecting UV light, these molecules absorb UV radiation through their chemical bonds. As the bonds absorb UV radiation, the components of the sunscreen slowly break down and release heat.) that absorb UV and inorganic pigments that absorb, scatter and reflect UV. To deliver a high level of protection, a sunscreen product must have sufficient quantities of these protective agents and it must optimally deploy them over the skin's peaks and valleys. Some inorganic chemicals, including minerals such as zinc oxide or titanium dioxide, act as a physical sunblock. They reflect UV rays, similar to how white paint reflects light. The white-colored noses on beach-goers in the 1980s and 1990s were due to these compounds; because manufacturers make the inorganic particles much smaller now, we don't see the visible white. The term SPF that appears on sunscreen labels stands for Sun Protection Factor, but it is really a sunburn protection factor. Products with a higher SPF allow fewer of the photons that produce sunburn to strike the skin. In simple terms, you can view an SPF 10 sunscreen as allowing 10 out of every 100 photons to reach the skin and an SPF 20 product as allowing only 5 out of every 100 photons to reach the skin. Because sunburn is primarily a UVB effect, it is possible for a sunscreen product to deliver high SPF while allowing a significant percentage of the incident UVA photons to reach the skin. To deliver true broad spectrum protection, products must also block a significant fraction of the UVA photons. In the U.S. market, this requires that the products contain significant levels of zinc oxide, avobenzone or titanium dioxide. ____________________________________________________________________________________________________ [Source 1]( URL_1 ) [Source 2]( URL_0 )"], "text_urls": [["https://www.livescience.com/32666-how-does-sunscreen-work.html", "https://www.scientificamerican.com/article/how-does-sunscreen-protec/"]], "score": [9]}}, {"q_id": "6k8by4", "category": "Repost", "title": "Why do I have to restart my computer when I update a program/app, but I don't have to restart my phone when I update programs/apps?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djk1atq"], "text": ["On a computer, programs tend to have \"root access\". This means that a program can edit parts of your computer other than the program installation itself. (eg: the registry) When a program needs to edit other parts of your computer, the computer needs to restart for these changes to take effect. Other programs may be using the same areas that the new program is trying to edit to install itself, or certain logs may need to be refreshed when the computer restarts. When you restart your computer, it refreshes those other areas and the computer knows about the new changes. Unlike a computer, when you install an app on your phone, that app only has access to the part of you phone designated for that app. (Like workers, restricted to their own cubicle.) Because the app doesn't need to edit more critical areas of your phone, it doesn't need to restart the whole system for those changes to take effect."], "text_urls": [[]], "score": [3]}}, {"q_id": "6k8gwi", "category": "Repost", "title": "Why do we feel embarrassed ourselves when we watch an embarrassing moment from a tv show?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djk43o7", "djk2dqt", "djk658l", "djk3p31"], "text": ["The thing is we are not sure. But these are the plausible reasons which are widely agreed on : **Empathy** It is a psychological reaction which pretty much relates someone else's body to our own. It exists so that humans could work together better and to have us avoid killing each other in most cases. Well, the face reaction is really just us putting ourselves into that persons shoes, and reacting how they would. But there is this study that claims it has nothing to do with how empathetic the person is. - [Link]( URL_0 ) From an evolutionary view it is beneficial for us to easily remember bad memories. This helps us avoid repeating mistakes we have witnessed and keep us out of dangers way e.g. My friend was eaten by a bear in that cave, I remember this in great detail and avoid that cave in future so I'm less likely to be eaten by a bear. I think it might be similar for things we find embarrassing. It's dangerous to do things that alienate you from a group since we are social creatures that rely on acceptance and group work to survive. If we remember things we've done before that threatened our social standing then we aren't likely to repeat the behaviour in future and avoid exclusion. That's just speculation though. for people asking for more info on this I highly recommend looking up evolutionary psychology 'Evolutionary theories of emotion view emotions a s adaptive traits - they help the organism to adapt to the demand of the environment and thereby survive' (Izard, 1977; Plutchik, 1984). ______________________________________________________________________________________________________ [Source]( URL_1 )", "The German's actually have a word for this, Fremdsch\u00e4men. There's varying theories as to why embarrassment is good or bad, but it really boils down to surviving in the social and cultural customs of whatever group (tribe) you're in. If you don't fit in you aren't finding a mate. Feeling the embarrassment of your friend when they're unaware that they're not fitting in allows you to step in and save them, with the understanding that they'll do the same for you...you could think of Fremdsch\u00e4men as nature's wingman. You have to keep in mind that at our core we're still very much socially dependent pack animals. A key part of being able to survive as long as we have is our ability to empathize with others. We're capable of feeling the pain, embarrassment, and even joy of others, which compels us to help and support one another.", "People have already mentioned mirror neurons and vicarious embarrassment but I think the key feature that a lot of people are missing is this. When you do something embarrassing, you elicit a negative response from the people around you, which causes tension and discomfort among the group. The most extreme case of this would be being ostracized from a group which would significantly lower an organism's chances for reproductive success. Thus, when our brains view someone else in an embarrassing situation, we recall the feelings (often literal physical feelings) of what it was like to be embarrassed; basically your brain's way of telling you \"remember how bad that feels? Don't do that!\" much the same way we remember and avoid physical pain. Basically, feeling vicarious embarrassment is our brain's way of \"sandboxing\" the emotional experience and subsequent processing of being embarrassed without having to first actually do something embarrassing. It's our brain warning us that whatever that person did that embarrassed them, we shouldn't do because it will feel super bad and risk being cast off from the group.", "Humans contain mirror neurons, which allows our brain to experience a few of the same feelings associated with an act we are viewing. For instance, sports. People watch football and they enjoy it. These motor neurons might possibly have an evolutionary advantage of allowing us to become more sociable, by understanding peoples emotions through vision alone."], "text_urls": [["http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0018675", "https://redd.it/61zcu6"], [], [], []], "score": [106, 29, 7, 4]}}, {"q_id": "6k9z80", "category": "Repost", "title": "Why does far away road look like it's covered in water when it's hot out?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djkenk3"], "text": ["Light passes through different temperatures of air at different angles. So when the sun heats up the road, there's often an area of hotter air above the road surface. As the light from the sky comes towards the road, it encounters that hotter air, and its path becomes bent. Sometimes the change is steep enough that instead of you seeing light coming from a relative straight path (the road) you're seeing light redirected from the sky, so as far as your eyes are concerned, there's [sky where you should see road.]( URL_0 )"], "text_urls": [["https://s-media-cache-ak0.pinimg.com/originals/28/df/6f/28df6fc8bdd28efd8bd4455cee8e2981.jpg"]], "score": [11]}}, {"q_id": "6katzf", "category": "Repost", "title": "How can birds sit on electricity cables and not be electrocuted?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djkm6s4"], "text": ["Electricity will always seek to flow through the path of least resistance. If it can flow at all, it will go through the conductor that is lowest in resistance to the flow. When a bird perches on an electrical wire, there's no change in the bird's electrical status- it offers no easier path for electricity to flow, because it's already flowing through the wire, which is *far* lower in resistance than a bird is. If a large bird or other animal were to touch two wires or one wire and the ground (or a conductor that connects to the ground) at the same time, then it would create a path between two different electrical states (called *potential*), and then electricity would flow between those two wires through the animal. Probably very briefly, as the animal would die or burn up almost immediately. Editing to add: Almost no electrical cables on power poles are insulated because it costs more, the insulation can crack and wear away, and it serves no purpose other than to increase expense and weight. Only in some specific circumstances are overhead power lines insulated, and it's not common."], "text_urls": [[]], "score": [14]}}, {"q_id": "6kccc7", "category": "Repost", "title": "How do 'Glow in the Dark' objects work?", "title_urls": {"url": []}, "selftext": "Does it work the same for all glow in the dark stuff? E.g Glowing wall stickers, Glow sticks, Clothing", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djkz0av", "djkz7yg", "djl3fzi"], "text": ["I'm very tired so I'll give a short winded shitty response but you'll probably get the gist of it. Glow in the dark objects contain a compound (phosphors) that can be excited by light. The compound absorbs the light energy by using it to put its electrons in a higher energy shell. If you imagine the Bohr atomic model with the rings around the center, the electron would be moving away from the center therefore occupying a high energy state. The atoms in the compound then release the energy via moving the electron back to its lower energy state (closer to the middle of the atom) and this energy release is given off as light. What color the light is when it's released depends on what compound is used, and what wavelength/energy value is absorbed/emitted by that compound. So to answer your second half of the question- no, not all glow in the dark objects use the same compound. There's more to it and I'm sure someone will take the time to explain it but that's the simple version", "Glowsticks operate via chemiluminescence, which is a fancy way to refer to a chemical reaction that produces light. You know that a chemical reaction is occurring because you need to mix the two chemicals in the glow stick to activate it. Phosphorescence, on the other hand, is the mechanism for glow-in-the-dark pigments that need to be \"charged\" by exposure to external light. Phosphorescent chemicals absorb light and then re-emit it slowly, at a lower intensity after a relatively long period of time. Radioluminescence involves using a radioactive element to excite a chemical that then emits the energy as visible light. This used to be highly popular, but that was at a time when radioactive water was marketed as a health tonic.", "Atoms absorb and reflect light. Leaves on a tree absorb light and only reflects green light. Glow in the dark objects are the same. They need to absorb light before they can glow, thats why after a while they become very dim if they haven't been under the light for a few hours. The reason why they glow in the dark unlike other objects is called phosphorescence. The object absorbs light but they don't reflect it instantly. The energy of the light thats absorbed is slowly released over time. What happens inside the atom: In normal objects the electron of the atom absorbs the photon of light. This gives the electron energy, the electron is what we call excited. The electron then releases that energy again in the form of light which we see. Objects that are phosphorescent have electrons that absorb light, but releases it in small steps over a long period of time. Hope this was easy to understand."], "text_urls": [[], [], []], "score": [73, 41, 4]}}, {"q_id": "6kdoda", "category": "Repost", "title": "Why do our bodies sweat and try to cool down when the temperature outside is 98\u00b0, isn't that the normal temperature for our bodies?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djl9d3o"], "text": ["Humans are exothermic. We generate our own heat and are capable of overheating. The higher the ambient temperature the harder it is for our bodies to exhaust excess heat."], "text_urls": [[]], "score": [5]}}, {"q_id": "6kgmgm", "category": "Repost", "title": "What is the advantage to society in funding NASA?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djlv7kh"], "text": ["Space is a very valuable resource. Communications and scientific experiments conducted there are much, much better and cheaper than land-based counterparts. NASA investments are improving efficiency in the use of this resource, reducing the cost to get mass into space, and understanding how to more effectively support humans in space. It took decades of NASA investment to get launch rockets to the point where rather esoteric private companies could participate, and their participation is still mostly funded by NASA. Companies can't take that sort of ling-view, it takes collective action through a government agency."], "text_urls": [[]], "score": [3]}}, {"q_id": "6klax6", "category": "Repost", "title": "How can 2 (3?) gas atoms (H & O) form a liquid (H2O)?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djmxrwo", "djn35of", "djmxuc5"], "text": ["3 atoms, It's H2O, two Hydrogen one Oxygen. It forms a larger, heavier molecule. Keep in mind a water molecule can be a gas, liquid, or solid, and it just happens to be liquid at the kinds of temperatures and pressure we're used to on Earth. There is gaseous water vapor in the atmosphere all around you (unless you're in Death Valley or somewhere equally frighteningly devoid of water) and many places have solid H2O (ice & snow) Hydrogen & Oxygen can also be liquids, or even *solids* at the right temperature & pressure.", "Hydrogen bonding is why water is a liquid at room temperature despite being made of gaseous atoms. CO2 has a heavier atomic mass, but is not a liquid at room temperature. Because of hydrogen bonding, all the water molecules form a lattice structure where all the molecules are, more or less, slightly bonded together due to electronegativity. Oxygen only needs 2 electrons to complete its valence shell and hydrogen is fine sharing its electron to empty its valence shell as well. Because of this, hydrogen has quasi-positive charge and oxygen has a quasi-negative charge which creates attraction between the atoms between molecules. Here's a [picture]( URL_0 ).", "I'm not sure exactly what you're asking...but I'll give it my best shot. Water molecules are liquid at ambient temperature and pressure because they don't have too much energy to not be in an ordered matrix solid, but not enough to form freeflowing gas. That's thanks to water's molecular structure and its asymmetrical shape making it a polar molecule (has a + and - side, why its so good at dissolving stuff like salt and alcohol too). H2 and O2 on the other and are symmetrical molecules so they stay gasses at ambient temperate and pressure."], "text_urls": [[], ["https://opentextbc.ca/anatomyandphysiology/wp-content/uploads/sites/142/2016/03/210_Hydrogen_Bonds_Between_Water_Molecules-01.jpg"], []], "score": [11, 4, 3]}}, {"q_id": "6km8hk", "category": "Repost", "title": "How come photons can travel through a solid substance like glass, but not through another solid substance like rock?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djn4jdt", "djn6m9r"], "text": ["Glass, diamond, and other \"transparent\" substances are transparent because they do not have the ability to absorb the frequencies which make the light we can see. Objects which are \"opaque\" can absorb the frequencies of light we can see. All substances have frequencies which they can't absorb and frequencies which they can absorb. These frequencies depend on the substance. Diamond, for example, is clear in the visible frequencies, but opaque in some of the infrared. Wood is composed of many different substances, and is opaque in the visible and infrared, but fairly transparent in the microwave and radio range.", "A video from Sixty Symbols which may help you. URL_0"], "text_urls": [[], ["https://www.youtube.com/watch?v=Omr0JNyDBI0"]], "score": [48, 6]}}, {"q_id": "6kmhc7", "category": "Repost", "title": "What determines how much money one currency is worth in another currency?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djn72rq", "djn6yfp", "djn6x9h", "djn7n6l", "djn8aba"], "text": ["The Market. And the market is all of us. Let's say we're on an actual market. Someone is selling 100 dollarydoos for 200 euros. Someone buys it, so now 1 dollarydoo = 2 euros (and 1 euro is 0.5 dollarydoo). A day later he want's to exchange his remaining euros again for dollarydoos so he's says he is selling 100 euros. Fortunately for him, there are a lot of ppl trying to get euro's, so someone offers him 60 dollarydoos for it. So now 1 dollarydoo is only 1.66 euro's (and 1 euro is 0.6 dollarydoo). So the price is whatever the other guy is willing to pay for it. And as there are a lot of sellers and a lot of buyers the price will eventually settle on some point. That is, until something happens (and something happens all the time) that causes there to be more sellers or more buyers and it causes the price to fluctuate.", "The short answer is: it's worth whatever someone is willing to pay for it. The long answer is: the ratio between a common asset. So if coin 1 has a 0.1btc cost and coin 2 had a 0.4 btc cost, then the cost of coin 2 is 4 coin 1's. If it gets too out of balance, then there is a arbitrage opportunity where you can make nearly risk free money by buying one coin in btc and immediately selling it for the other coin and going back to btc.", "The same thing as what determines what any commodity is worth, it's worth whatever someone is willing to pay for it. Now in terms of what makes a currency more or less desirable and thus changing what people are willing to pay for it there's a lot of factors going into play including things like interest rates, inflation, and the general condition of the economy that the currency belongs to.", "One of the major factors is something known as Purchasing Power Parity. You may have heard of something called the Big Mac index which is an informal way to test wether commodities in two different countries cost the same relatively. Currency like most other things is largely controlled by the forces of supply and demand although you do get fixed exchange rates. If you take a basic economic assumption that firms are profit maximisers a domestic USA firm that needs steel to produce its goods is looking to purchase that steel at the lowest cost it can. Say domestic steel is $100 a unit and Chinese steel is 540Yuan (80 bucks) a unit the firm will purchase the Chinese steel assuming they're the same quality. You would then have to sell your dollars on the market to purchase yuan in order to buy the steel. This should cause an appreciation in the yuan and a depreciation in the dollar ( your dollar is now worth less yuan). If you look at the wider economy eventually all these transactions should lead to a point where steel is the same price relatively in both countries however in a fixed exchange rate (or pegged) the Chinese would be constantly monitoring the rate and making sure they never lost their pricing advantage. In order to do this in this example they will sell their Yuan to buy dollars (making Yuan worth less dollars) and thus maintaining their advantage. You also have something called hot money. Basically investors around the world looking for the best return on their investment. Take the Bank of England interest rate of 0.25%, very low compared to most other countries and historically. If the UK independent from government, monetary policy committee decided to raise this interest rate, hot money would flow into the country thanks to the higher returns available. This will cause an appreciation of the exchange rate Hope that makes sense, I tried to write an answer at a high school economics level, when you get to undergraduate level things start getting much more complicated and this is a bit of a simplification.", "Firstly: My source is that I'm an accounting graduate. A few months ago one of my modules involved researching specifically this. Basically, there's a lot of different factors so I'll tackle them one at a time, just bear in mind it isn't an exact science. Some of the more obvious things are more self explanatory so I'll combine those. There's a TL;DR at the end. Firstly, confidence is a big thing in the markets, the same way it is with shares. Things like Brexit, changes in economic policy and swings in government can all make short term spikes/dips. These will typically stay at the altered amount until something comes along to change it, although it can slowly recover from the shock. Also, stuff like wars (both in your own and neighbouring countries) can affect it. Much of these are linked to demand for the currency. Take brexit (as I'm in the UK). The basic fear with brexit was what deal we could negotiate, and how that would affect the finance sector. That sector is a HUGE part of Londons, and therefore the UKs, economy. As a result, the risk averse want to remove their money BEFORE the currency tanks due to financial services leaving the capital. The effect of this is higher supply (for less demand as well) for the currency, as everyone is selling. Whenever supply rises relative to demand, you expect prices to drop. This is partly why the Euro/US dollar is so stable - a huge amount of global trade is done in dollars/Euros so the supply and demand is relatively stable. Interest rates are another factor, as is the amount of money in circulation. These also both tie into PPP (**Purchasing Power Parity**). PPP is a rule which basically states the overall buying power of a currency must stay the same, there is a delay in reaching this equilibrium. The way it works, is if inflation goes up, the currency must become cheaper. Otherwise, the purchasing power will fall. Example below in italics. *EG if the rate of inflation rises in the UK, but the strength of the \u00a3 stays the same then other countries will find it more expensive. When you change over $100, you still get \u00a3150, but that \u00a3150 won't get you as much. Therefore, the $100 has less purchasing power. So the currency needs to become weaker. When this balances out, your $100 gets you \u00a3170, which now gets you the same amount of stuff as \u00a3150 did before the rise in inflation.* This works both ways. The difficulty in applying this is two fold: You don't know which side of it is causing it, and you don't know exactly how long the previously mentioned delay will be. Now, it's worth noting that there are many ways these things can be affected indirectly. Demand for the currency could be increased by attracting a lot of foreign investment through things like corporation tax cuts. Inflation is affected by interest rate changes. The Bank of England directly meddled post brexit to stabalise the currency, and we still had the most spectacular nosedive in living memory. Furthermore, no one has perfect information. I define perfect as \"knowing everything\". Any given person has a small part of the picture, not the whole thing. Much of what affects it is often outside of any individuals control, or even totally unforeseen. TL;DR Demand and inflation are 2 of the core reasons, but they are linked. Also, many, many things feed into those 2 factors. So really, there isn't a definitive answer short of \"everything\"."], "text_urls": [[], [], [], [], []], "score": [122, 51, 13, 4, 3]}}, {"q_id": "6koahq", "category": "Repost", "title": "Why do we have to pay for internet? What natural resources are being used to supply internet rather than space? If that's the only thing why is it not payed through taxes like roads and other public services?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djnj0pm"], "text": ["Internet providers have to lay down miles and miles and miles of cables, including cables *on the ocean floor between continents* (this is usually done by large companies that your ISP than has to pay to be able to use those cables). They have to install routers and switches. Those routers and switches have to be inside buildings, for which rent has to be paid. All of that equipment has to be maintained and sometimes replaced, which costs money and is done by people who have to be paid money. If something goes wrong with your Internet service, you have to be able to call someone to report the problem and get it fixed. So they need a call center staffed with employees (who have to be paid) to sit at desks (which have to be purchased) and answer the phones (which also have to be purchased), using computers (you get the idea). They also have to pay for rent, water, electricity, and insurance on that building. As well as salaries for managers, human resources, janitors, repair technicians etc. And if your ISP has a website (hint: it does), they have to pay web developers to design and maintain the website. As well as programmers to design and maintain all of the backend systems that handle the website. And then there's he billing department, and public relations department, and marketing department, and legal department, etc. It's a huge business employing a lot of people and requiring a lot of expensive equipment. All of that has to be paid for somehow."], "text_urls": [[]], "score": [6]}}, {"q_id": "6koi9x", "category": "Repost", "title": "Dust bunnies", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djnpxbt"], "text": ["They are small clumps of dust that form under furniture and in corners that are not cleaned regularly. They are made of hair, lint, dead skin, spider webs, dust, and sometimes light rubbish and debris, and are held together by static electricty. They can house dust mites or other parasites, and can lower the efficiency of dust filters by clogging. The movement of a single large particle can start the formation of a dust bunny. They are especially bad for electronic components because they can clog up the air flow, thus increasing heat and shortening the lifespan of electronic components."], "text_urls": [[]], "score": [12]}}, {"q_id": "6kqf5g", "category": "Repost", "title": "How does the body age while in a coma? Would resting for long periods slow down aging?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djo2b1u"], "text": ["You would age the same as anyone else except you would have gone through a state of atrophy where your muscles were not being used which causes them to break down. Your body is still working to keep you alive and the components of your body will not age slower just because they are not being used as much. Somewhat off topic but the only way I've personally heard of someone aging slower is through something called \"relative velocity time dilation.\" The basic premise is that you age slower the faster you are moving based on the theory of relativity. There is also something called \"gravitational time dilation\" which states that the aging process decreases when gravitational force increases."], "text_urls": [[]], "score": [5]}}, {"q_id": "6kr0y6", "category": "Repost", "title": "How do they colorize old black and white video.", "title_urls": {"url": []}, "selftext": "I have been seeing ads for a show called America colorized, I think, that is colorizing old black and white videos. How do they do this?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djo7a3n"], "text": ["Simplest answer, they paint it. Back when they first started colourizing black and white film, someone would sit with a brush and dyes and colour it by hand one frame at a time. When you think that there's 24 frames in a second, you can imagine how painstaking it would be to colourize a feature length film. Plus the results never looked natural. Today, it's still largely done the same way, all be it digitally. With tools like Photoshop, you have a much larger palette than they did back in the old days. You can also make changes to the base image, which couldn't be done prior to digital photography. Which is why skilled artists can make more realistic colourized photos and videos. It's still a painstaking process though, and they'll rarely look as good as a photo or motion picture taken on colour stock. Even colour stock of the era."], "text_urls": [[]], "score": [4]}}, {"q_id": "6kr8ta", "category": "Repost", "title": "If vegetables are good for you, why do soda, chips, and other \"junk food\" taste better?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djo6rfx"], "text": ["Sugar, salt, and fat are critical for the human body to work. Our brain users more sugar than any other part, salt is needed to conduct electricity, and fat is of course an excellent store of energy. You and I are unfortunately a very old model, stuck in modern times. Human beings haven't had a major evolution in 35,000 years. We are essentially designed to be the perfect hunter gatherers, but that's not been our role in a very long time. Our tastes turn us on to exactly what our ancestors needed the most, but in the age of the Big Mac that's exactly what we have too much of."], "text_urls": [[]], "score": [15]}}, {"q_id": "6ktfok", "category": "Repost", "title": "Why do people tend to cover their mouths in a moment of awe, disbelief, shock, etc.?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djop4if"], "text": ["Shouldn't it be why do they drop their jaw, cuz I believe that's why they're covering their mouths"], "text_urls": [[]], "score": [6]}}, {"q_id": "6kvuib", "category": "Repost", "title": "Why do we get light-headed or faint when standing up?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djp6g99"], "text": ["Mostly, it is a sign of low blood pressure or adrenal exhaustion. It takes pressure to raise a column of water a certain height. You are the height in this case and the water column is your blood. As you stand, your body has to increase the blood pressure to keep everything in balance. It is natural for a well person with normal blood pressure to be able to do this fast enough to have no or only a momentary light-headedness. Try this experiment. Get a blood pressure cuff. Lay down for two minutes, take your blood pressure, then stand up and take it immediately afterwards. Your blood pressure should rise about 10 points on the top reading to keep you feeling healthy. If not, look up adrenal exhaustion on the internet. Doctors will tell you that it doesn't exist. It does."], "text_urls": [[]], "score": [3]}}, {"q_id": "6kwq8r", "category": "Repost", "title": "Why do ribbons curl when you run a scissor blade against them?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djpftqu"], "text": ["Full disclosure I'm not completely sure what ribbons are made of, but I would venture to say that this is the reason: It's basically that you're bending it. Ribbon is very flexible in a sense, and bends without bending permanently (called elastic deformation). But if you bend it in half and pinch it flat, you'll notice that it stays bent when you let go (plastic deformation). When you run scissors across the ribbon, you're plastically bending it along the whole length of the ribbon, so it curls."], "text_urls": [[]], "score": [5]}}, {"q_id": "6kxheu", "category": "Repost", "title": "Why is prostitution illegal in the U.S. But if you pay somebody to have sex with you, film it, and post it online then its fine?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djpk2ze", "djpjqov"], "text": ["> if you pay somebody to have sex with you, film it, and post it online then its fine? That's actually *not* fine. You have to have all kinds of licenses, you have to hire the \"actress\", which involves getting her social security number to fill out tax documents as her employer, and it's still not legal to film porn in all 50 states. Just filming sex with a prostitute and calling it \"porn\" doesn't make it legitimate porn, and won't stop you from being charged with solicitation.", "You actually have to get licenses to film porn with paid participants. It is also not legal to make in every state or city, many places do not grant the licenses. So the idea that you can just make it and post it online and it be fine is not accurate. The logic, whether you agree with it or not, is that you are hiring someone to be an actor/actress for a project that happens to involve sex. You are not actually paying for them to have sex, and more importantly you are not paying them to have sex with you but with each other."], "text_urls": [[], []], "score": [3, 3]}}, {"q_id": "6kz94f", "category": "Repost", "title": "Why are ultra enlarged objects not in color?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djpvtjz", "djpw4ik"], "text": ["The cameras that see that small are called electron microscopes. They don't see in the visible light spectrum like regular cameras. Google them, they're pretty cool.", "Colors are not a phenomenon that is intrinsic to objects. Objects simply reflect some wavelengths of light. It is our brain that attributes colors to certain wavelengths. As objects get magnified more and more, the wavelengths of light we can see get too big to resolve those objects. That is, a wave with wavelength 700nm cannot resolve an object that is 0.1nm big. Thus, we have to use objects with smaller wavelengths - like electrons. Electrons, however, are not associated with color in our brains, so we simply have to resort to black and white images."], "text_urls": [[], []], "score": [7, 7]}}, {"q_id": "6kzaxj", "category": "Repost", "title": "Why do drinks taste better when they're stored in glass containers?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djpw7n7"], "text": ["If you store a drink in a metal or plastic container the metal and plastic will slowly dissolve into the liquid. It does not happen in any quantities as to be harmful however it may have a slight effect on the taste. Glass on the other hand is much more stable and does not dissolve into the liquid at any measurable rate. This is also why glass is very commonly used in chemistry as it does not taint the chemicals."], "text_urls": [[]], "score": [4]}}, {"q_id": "6kzger", "category": "Repost", "title": "Why, in a 24/7 digital economy, does it still take several days for a check to clear between banks? Where does the money go in the meantime?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djpyjn3"], "text": ["Back in the eighties when interest rates were quite high, banks here in New York were notorious for taking a very long time to clear checks (4 or 5 days IIRC). Even a certified or bank check would take days to clear. The banks were basically making money off the interest while it \"floated\" in their system. I think regulators eventually stepped in, limiting the time they were allowed to float the funds. Modern banking is much faster now and although there is obviously a certain amount of time necessary to validate checks and transfer funds I'd venture to say it's a fraction of the time they actually set aside. They're making money off your money (albeit at a pretty small interest rate)."], "text_urls": [[]], "score": [3]}}, {"q_id": "6kzhqt", "category": "Repost", "title": "What prevents different platforms like XBOX, PS4 and PC from reading other game discs? If they can all read multimedia discs, how are game discs different?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djpz6hh"], "text": ["It's not the physical discs that really matters, it's the format of the data on it. Different games consoles have different operating systems, and sometimes different hardware (although the PS4 and Xbox One are pretty similar in terms of hardware). Games programmed for one OS won't work on a different, incompatible OS. Imagine Xbox One games are written in English and PS4 games are in Japanese. The Xbox One only understands English, the PS4 only understands Japanese. So even though they can both physically see the game's data, they can't make sense of it."], "text_urls": [[]], "score": [3]}}, {"q_id": "6l0lzd", "category": "Repost", "title": "let's say all humanity is wiped out apart from 1 breeding pair. Would repopulation be possible if so how many generations would it take before there is no negative effects from inbreeding?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djq6hxm", "djq7q1f"], "text": ["Minimum viable population size is somewhere between 1,000 and 4,000 individuals depending on species. I don't think anyone has calculated it specifically for humans yet, but there would be a lot of factors including how genetically similar the population is (you wouldn't want to pick a single family unit at the smaller population size). Smaller populations are possible, but would require more careful breeding and husbandry to prevent negative effects. 1 breeding pair is definitely too small.", "Such a scenario would doom the human race. The problem isn't so much the ability of the human pair to produce viable offspring. It would be enormously difficult, but probably possible, to get a stable population going if you had access to some sophisticated technology to help you. The real issue is the genetic bottleneck. By having only two humans, you restrict every single one of their offspring to some combination of their genetic material. Having a \"deep\" Gene pool is tremendously important for organisms, as it allows for resiliency to disease and other threats. All it would take is an opportunistic virus to infect one of the parents or children, and unless they have a robust immune system (which they might not because of the inbreeding) and that virus could very easily exploit any genetic weaknesses that are present in the population and kill everyone. To say nothing of the dangers of inbreeding alone -- humans become very unhealthy with successive generations of incest, which you would have to have in order to make a decent population. And since everyone has very similar genetic material, it would be a constant concern. So no, I don't think two people could repopulate earth unless they have access to some very sophisticated genetic manipulation technology."], "text_urls": [[], []], "score": [7, 3]}}, {"q_id": "6l26tk", "category": "Repost", "title": "How can my microwave have a metal rack in it if I'm not supposed to put metal in the microwave?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djqiz30", "djqngqh", "djqr98a"], "text": ["Metal in microwaves is not an absolute rule. It's just that trying to explain the nuances of what types of metal you can use in a microwave, and when you can use them, to the average microwave user, is more than most microwave manufacturers are prepared to do. So the general rule is don't ever put metal in a microwave. If the metal thing is shaped properly, it won't matter. It's just the average metal thing you'd put in a microwave isn't shaped properly to not end up sparking and arcing when you start it up. As you may have realized by this point, the rack that comes with a microwave is very carefully designed to work properly within one.", "What you want to avoid is creating electrical arcing. If you put a crinkled sheet of aluminum foil in a microwave you will see electric arcs jumping between the peeks of the folds. Big enough arcs can ignite other materials in the microwave. Sometimes arcs can travel all the way back to the magnetron and burn out the electronics. The metal rack is designed so that arcs won't occur.", "My microwave manual actually says you're to leave a spoon on the cup if you are heading a liquid. I think that this is to prevent super heating above boiling point (the temperature of, say, water is above 100\u00b0C but no bubbles). This could cause spontaneous bubbling when you take it out, splattering you with hot water. The spoon would act as nucleation point where the bubbles could start. No metal in the microwave refers to thin metal which could spark, or metal containers which would block the microwaves from the food your heating. Bonus trivia: the first microwaves didn't have a rotating plate, but had a rotating metal \"stirrer\" that reflected the microwaves around the oven minimising ~~hot~~ cold spots"], "text_urls": [[], [], []], "score": [8, 3, 3]}}, {"q_id": "6l4712", "category": "Repost", "title": "When using slow internet how does advertisements quickly load in high quality while the actual content can not?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djr0suw"], "text": ["The two main reasons, although there may be more, are 1. The file size of an ad is likely much smaller than a YouTube video because they're usually only 15-30 seconds. 2. Ads are not actually being shown by the page itself. The ads are ran from dedicated ad ~~several~~ servers. Yes, Google probably cares much more about playing that ad than showing you the video and I definitely wouldn't doubt the ad servers have priority over resources."], "text_urls": [[]], "score": [4]}}, {"q_id": "6l64go", "category": "Repost", "title": "Why do thunderstorms have that \"Smell\" before it starts raining? What is it we are smelling?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djrdvzv", "djrtlnj"], "text": ["Weather patterns produce distinctive odors that sensitive noses sniff out. **Before the rain begins**, one of the first odors you may notice as winds pick up and clouds roll in is a sweet, pungent zing in your nostrils. That's the sharp, fresh aroma of ozone. (An electrical charge\u2014from lightning or a man-made source such as an electrical generator\u2014splits atmospheric nitrogen and oxygen molecules into separate atoms. Some of these recombine into nitric oxide, and this in turn reacts with other atmospheric chemicals, occasionally producing a molecule made up of three oxygen atoms\u2014ozone, or O3. The scent of ozone heralds stormy weather because a thunderstorm's downdrafts carry O3 from higher altitudes to nose level.)", "This smell is referred to as petrichor. The main cause for this scent, is, as some suggest, not actually ozone. Rather, it is caused when rain makes contact with ground soil [(MIT)] ( URL_0 ). This aerosolizes certain compounds, as well as bacteria and viruses, that were trapped in the soil. You likely smell this before you actually see any rain because there is still plenty of rainfall, just not right where you are. The same pressure systems that move the storm to you also move the aromatic particles to you, and therefore, you can smell the storm."], "text_urls": [[], ["https://newsoffice.mit.edu/2015/rainfall-can-release-aerosols-0114"]], "score": [36, 3]}}, {"q_id": "6l680e", "category": "Repost", "title": "Why are we able to eat beef not cooked all the way through (e.g. rare) but not other meats like chicken?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djreknv"], "text": ["It depends on the bacteria that can grow on them. Beef meat is not having any bacteria inside, and the outside cooking is enough to remove possible pathogens. In chicken you can have pathogens in between the meat like Salmonella, thus you need to cook it well."], "text_urls": [[]], "score": [5]}}, {"q_id": "6la0an", "category": "Repost", "title": "What purpose does the wedding quote \"speak now or forever hold your peace\" have and what happens if someone does object?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djs810s"], "text": ["It's a hold over from the past when marriages were prearranged with a contract and sometimes previous betrothals could be a legal impediment. That line means if you know of any legal impediment like a previous contract or secret marriage/consummation this is your last chance to bring it to light. This isn't an issue now. If you spoke up now you'd probably just piss everyone off."], "text_urls": [[]], "score": [3]}}, {"q_id": "6lda8r", "category": "Repost", "title": "What exactly causes the 'buzz' when you've had a few drinks of alcohol? What gives you that feeling of less sensation/etc?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djsxbt3"], "text": ["Alcohol slows down your central nervous system. The central nervous system accounts for your senses, motor function, etc. When you drink alcohol, everything is shortened and slowed down in your CNS. When the CNS is slowed down from the alcohol, You begin to experience light headedness, hazy thinking, slurred speech, a slower reaction time, and dull hearing"], "text_urls": [[]], "score": [3]}}, {"q_id": "6ldkyf", "category": "Repost", "title": "Why flying insects can't tell that a window is in front of them and repeatedly fly into it?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djszy9q", "djt06xu", "djt0tzz"], "text": ["If you had never seen a window before you would probably hit it a few times too before accepting that a completely transparent object can block your way, or perhaps you'd keep touching it while walking along it, searching for an equally transparent opening. I'm not sure the intelligence of an insect is enough to reach the accepting part though.", "Compound eyes don't focus. They see shapes and blurs and specialize in detecting movement.", "Flies are really dumb. Not only that, but their memories are practically nonexistent. Add that to the fact that they can't even see the window in the first place and there you go."], "text_urls": [[], [], []], "score": [44, 9, 5]}}, {"q_id": "6litym", "category": "Repost", "title": "Why does the filming of Soap Opera shows always look a certain cheapish way? Can't they afford better cameras?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dju6zxd"], "text": ["It's not so much the cameras as the lighting. Soaps are filmed quickly, using multiple cameras. In a movie, when you switch from one angle to another, the director will generally take the time to change the lighting to accommodate the new point of view. The director of a soap can't afford to slow down a production like that, so the sets tend to be very evenly lit, so the actors and cameras can move around without worrying about being in shadow. This results in a sort of blandness, where the actors do not stand out very well from the background."], "text_urls": [[]], "score": [3]}}, {"q_id": "6lktwo", "category": "Repost", "title": "Why is it illegal to collect rainwater in some US states?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djujaeo", "djus1qr", "djujul9", "djuko8f", "djutmne"], "text": ["This was orginally necessary to prevent owners of large ranches from being able to divert run off into holding ponds reducing or eliminating water which would otherwise be available to those further downstream. Your roof might seem inconsequential but if you imagine the loss of runoff if 1 million roofs were being diverted...it becomes significant. In some states the water is considered a state controlled resource and in essence you are stealing water from the states control when you harvest rainwater.", "Colorado was like this for years because there was a study saying that collecting rain water prevented it from flowing into rivers and downstream to states like California, or because the water way it drains to belonged to someone else. This law was written into the states Constitution. Recently there was an opposing study released the found 90% of rainwater never makes it to the rivers before being absorbed by the ground. Now you can store 110 gallons. URL_0", "While I cannot say whether this is the case in U.S. States, many places have outlawed rainwater tanks in the past because they allow mosquitoes to breed through the dry season. This allows dangerous tropical mosquitoes to survive in dry sub-tropical cities. Keeping things like dengue and malaria out of those cities was worth more than the individual benefit of individual rainwater tanks. Many of these laws have since been removed.", "Some states (mostly western) have very little rain fall and the water is very valuable while the land itself is not. In some of these states one can buy the property rights (build a house/driveway), water rights (rain that falls on or is found under) the land, and mineral rights (oil/gas, gold, etc) all separately from each other.", "in st petersburg, fl they actually encourage us to collect rain water in big barrels and then use it or dump a day after a storm... helps stop flooding during rain storms."], "text_urls": [[], ["https://www.washingtonpost.com/blogs/govbeat/wp/2015/03/24/it-is-actually-illegal-in-colorado-to-collect-the-rain-that-falls-on-your-home/"], [], [], []], "score": [150, 30, 22, 12, 4]}}, {"q_id": "6llckp", "category": "Repost", "title": "Is there a cultural or historical reason why America developed its own measurement system?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djumnf2"], "text": ["Brits arrived, taught imperial system. Brits left, moved on from imperial system. USA didn't."], "text_urls": [[]], "score": [8]}}, {"q_id": "6llqg8", "category": "Repost", "title": "How can there be all type of frequencies and waves in the air (Bluetooth, Wifi, Radio) and we are not physically affected by it? Shouldn't our watery or brainy components be affected to some degree?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djupout"], "text": ["Ultimately it matters how energetic they are. Radio waves in the air can be as benign as a flashlight shining on you, and you don't see complaints about that. So a radio wave in the air isn't really an issue, but if you lived with a 50,000 watt radio transmitter, that sort of energy could be dangerous. Just like getting too much UV from the sun. We can decide what devices are able to put out as far as energy yield. As far as what is in your home, your television would be more of a threat than your wifi router or your mobile phone."], "text_urls": [[]], "score": [4]}}, {"q_id": "6lpjcr", "category": "Repost", "title": "How do Radio Shows know how many people are listening to them?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djvltbh"], "text": ["It can be difficult to determine the ratings of over-the-air radio broadcasts, and has always been a thorn in the side of determining adverting rates, which is the most important part of running a radio station. But, in general, there are a couple of ways. One is to simply ask people through a proper scientifically sound survey done through mailers or phone calls. Ask enough people what stations they listen to, and you can extrapolate it with pretty good confidence. Another way is by using those call-in contests that you hear radio stations having all the time. There's a well established percentage of people who are likely to call in to the station for contests, and so by keeping track of how many people participate, you can roughly judge how many people are listening at that particular time. Obviously, for things like radio apps"], "text_urls": [[]], "score": [3]}}, {"q_id": "6lqebd", "category": "Repost", "title": "How do computers REALLY work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djvug9v"], "text": ["At the lowest level (almost), it runs due to the actions of transistors. Transistors in digital logic circuits are used mostly as switches. You want the transistors to be either all the way OFF (no current flow) or all the way ON (lots of current flow). And you can use the output of one transistor to control the input of other transistors, so you can construct a complicated circuit by wiring them up in certain ways. Using just a few transistors, you can build very simple logic circuits to implement binary digital logic (called \"Boolean\" logic after the guy who invented it). For example, imagine a light bulb hooked up to a battery through a switch. Switch on, light on; switch off, light off. Now imagine that there are two switches in a row, A and B. The light is only on if A and B are both in the on position. This is what a digital logic AND gate does! If you hook the switches up differently, you can just as easily make an OR gate (A OR B turns on the light). Label a switch backwards and you have a NOT gate. It turns out that you can build any digital logic function with a combination of just a few simple circuit types, such as AND/OR/NOT (you can actually do everything with just one, but no one really does that). By combining those simple circuits, more complicated circuits can be made (such as an adder, a multiplexer, etc.). You can use those circuits to make even more complicated ones. Like a CPU. It's like if you had a bunch of little Lego blocks, and you could use those to make larger Lego blocks, and you could then use those to make even larger Lego blocks, and so on. Today's integrated circuits use more than a billion transistors to make something that is very complex, but it is built up out of very simple things. Transistors are great for building these things because they are small, fast, reliable, cheap, and don't use a lot of power. These are all important properties when you are trying to make something that uses a billion or more devices. After you've built a bunch of different chips and put them into \"packages\", you solder those packages onto a Printed Circuit Board (such as a PC motherboard). The PCB has copper traces on it that act like flat wires to connect things together. (It is cheaper, simpler, better performance, and more reliable to use a PCB to do this rather than a bunch of individual wires.) It even has many layers, and connection vias going between layers or clear to the other side of the PCB. So now you can connect up different chips that do different functions, like CPU, memory, graphics, etc. They \"talk\" to each other via the traces on the PCB according to certain pre-determined rules, called \"protocols\". Kind of like the circuits, these protocols are built up in layers, with the lowest level protocol defining what signals mean \"0\" and what signals mean \"1\". These protocols get pretty complicated, and allow the different components to pass very complex information back and forth. The different parts of the PC have different functions, with the CPU acting kind of as the main brain and control center. It gets program instructions and data sent from the hard disc to the memory and then to it, manipulates the data as dictated by the stream of instructions, and sends data out to where it is needed. But the CPU does what it does according to the digital logic that has been built into it."], "text_urls": [[]], "score": [8]}}, {"q_id": "6lspo6", "category": "Repost", "title": "how did scientists figure out how to make computers?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djwbowg"], "text": ["The whole field built on top of other stuff over many years. First, people figured how to control electricity with electro-mechanical relays. Relays are binary - ON or OFF, like bits in a computer. Then they figured things like how to combine them to make a circuit that can make some basic boolean logic *gate* - for example, an OR gate, application may have been \"turn the lights on if any of these 5 light switches is on\", an \"AND\" gate might be \"only start this machine if the power switch is ON AND the operator has both hands pushing the safety buttons ON\". Those are the building blocks of logic, which can then be combined to do things like add up numbers or run a sequence of steps / make a basic decision depending on the state of various things. A lot of the early stuff was built around making mechanical telephone exchanges (Strowger) rather than requiring human operators - no coincidence that Tommy Flowers worked for GPO Telephones and most of the equipment at Bletchley Park will look *very* familiar to telephone engineers. So you have circuits of relays that **count** your sequence of pulses (dialled number) from your telephone, connect through the system **deciding** if a circuit is busy or available, etc. etc. it all starts to look a lot like a sort-of-computer. From there, you build up to making a system where you are able to change the *steps* or *decisions* (the program) without having to re-wire the circuit specially for each task, perhaps by feeding punched cards in or putting pegs in a board. All this can still be done with relays, or any other sort of controllable switch. In parallel to these advances in thinking about how to make \"computing machines\", electronics got smaller, faster, more efficient and reliable as valves replaced relays, then transistors replaced valves, then we put multiple transistors and things on a sliver of silicone to make a chip, then we put a whole load on one chip to make a processor... You could make a modern computer out of relays (or wood & marbles) but it would be huge, expensive, slow, and unreliable. If you search on URL_0 , some guy made an entire computer out of single transistors to demonstrate how it all happens, it plays tetris and takes up a whole room. He's done a really good job, written loads about how it all works & goes together etc. There's also nand2tetris which skips the first couple of steps but does cover most of it quite well."], "text_urls": [["Hackaday.com"]], "score": [7]}}, {"q_id": "6lt4oc", "category": "Repost", "title": "Why are we scared of bugs? They're just small animals.", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djweqnm", "djwdp8g", "djwdbrg"], "text": ["Insect fear is programmed into us by society. Children are not born with the fear, parents and stuff on TV programs it into them. I played with every type of spider and bug as a kid, then I got scared as a youth, now I am over it again. On that note, bugs are friends, I build edible forest gardens and work with bugs a lot. [Here]( URL_0 ) is a video of one of my spider Bros who asks for a ride, not once, but twice, to get to his Ladies nest on the other side. 1 minute. They do recognise you, and can be money and time saving minions when you train them to do the desired job. I trained yellow jackets to do pest control on my leafy greens in the garden. I left out sugar for the wasps, and they came to feed the pest caterpillars to their growing larva. Adult yellowjackets are vegetarian, only the babies require the protein. Keep in mind that venom from an insect is very energy intensive to produce. Wasting their super juice to bite a human may spell out their own death. Therefore there is little benefit to bite or Sting. I ohm to my minions in the garden, it allows them to associate a sound vibration with the giant who comes through and adds cools stuff to their world. It allows me to get right up to wasp nests with out getting attacked (note, do not do this, I can not promise your wasps will not get violently defensive) . They will even come out to see you. Sing if you prefer over ohming. Maybe stay away from death-metal lyrics. If you are interested, I spent 2016 turning a barren house in the desert into the most self sufficient biodiverse home in the region. On a small 90 square metre property we went from 2 species of bugs to over 50, all contributing to the maintenance and Fertility of the ecosystem. [Here]( URL_1 ) is the project summary, lots of bug pictures. The house generated no waste water, it was all recycled into food and growing the little oasis.", "Some are poisonous and can kill you, especially pre antivenom days. You would live longer if you were scared of them.", "I dont know if you need some extensive backround in human psychology to answer this but Id say bugs have quite the different exterior than our lovable fur coated creatures"], "text_urls": [["https://youtu.be/EbGpOoTU4gw", "https://drive.google.com/file/d/0B5mLitql1p9_bzc2aFdVSXp5cFU/view?usp=drivesdk"], [], []], "score": [9, 3, 3]}}, {"q_id": "6lvmck", "category": "Repost", "title": "If cells in your body do not live forever and tattoo ink is applied to skin cells, how are tattoos permanent?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djwwliw", "djwwvol"], "text": ["Tattoo ink is embedded in the deeper layers of skin, called the dermis. During this process the dermis is damaged, and as it heals, it forms fibrous tissue - the equivalent of scar tissue. The ink gets locked into it, and stays there. Scars do break down slowly over time, but the rate of cell replacement is hugely reduced. Regardless, tattoos will fade over time as the ink partially disperses, and the tattoo starts to get blurry. Sun damage also plays a part, but that's not related to this discussion.", "Ink is not applied to skin cells like a piece of paper, instead ink is injected in between the layers of skin. A tattoo is, really, simply shaped unabsorbed pools of ink being suspended in your skin."], "text_urls": [[], []], "score": [43, 8]}}, {"q_id": "6lwjxi", "category": "Repost", "title": "If a sail boat (say from a few hundred years ago) wanted to go west but the wind was blowing east, how would they go west?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djx4e02"], "text": ["URL_1 > Sails at a 15% angle to your boat will, when blown on from the front, push your boat forward, allowing you to sail perpendicular to the wind. So you tack the boat, switching sides, never sailing directly into the wind, but rather across it. Here's a handy picture. > URL_0"], "text_urls": [["http://nabataea.net/Photos/tacking.jpg", "https://www.reddit.com/r/explainlikeimfive/comments/1zdcxu/eli5_how_does_a_sailboat_sail_into_the_wind/"]], "score": [6]}}, {"q_id": "6lx7zi", "category": "Repost", "title": "How do we 'teach' a computer the length of time?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djx9pmv"], "text": ["Computers have quartz crystals that vibrate a known number of times per second when they are wired up. We tell the computer to count the oscillations and make time measurements based on the counting."], "text_urls": [[]], "score": [8]}}, {"q_id": "6lxlnz", "category": "Repost", "title": "why do restaurants in America not charge customers more for food and pay staff a higher wage rather than have them relying on tips?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djxd2n3"], "text": ["Let's say a restaurant does what you are suggesting. They raise prices, pay the staff appropriately and tell the customers not to tip. Well, now the food costs more than it used to. Customers will notice. They will be unhappy. They will look at the restaurant next door and see that their food is much less expensive. \"Maybe we should go there next time instead\", say some of the customers. Restaurant is now paying more in payroll PLUS they are losing customers. This is a pretty crappy situation for the business. Now they probably need to lay off employees to make up for the downturn. Very few owners are willing to intentionally drive the company into that sort of situation. You might say \"Well how come the customers don't realize that they aren't really paying more since now they don't need to tip?\" Well, customers aren't well known for noticing things that aren't directly in their line of sight, and will really only notice the higher prices on the menu and probably never even realize that there is a whole wage/tip thing going on in the background. Once a culture gets into this sort of routine, its hard for businesses to try and change it on their own, because their own business will almost certainly take a hit at best, and go under at worst. It's hard to ask people to risk their livelihood between those two options. That's not to say there aren't situations in which this will work. Each business has it's own unique economic situation, and there are places that can absorb the downturn in business, or maybe even get some good publicity if they play their marketing and advertising correctly. But on the whole it's a rough road to hoe for most places."], "text_urls": [[]], "score": [3]}}, {"q_id": "6lyy83", "category": "Repost", "title": "Why is it that 37 degrees (celsius) feels extremely hot to us even though that's our natural internal temperature?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djxo5fh"], "text": ["Because we're warm-blooded (hooray mammals!). That means that our body constantly produces heat. When the temperature outside of our body is the same as the temperature inside our body, then we can't get rid of heat easily. We have to rely on sweating to provide evaporative cooling, or we risk overheating and dying."], "text_urls": [[]], "score": [4]}}, {"q_id": "6lzlkh", "category": "Repost", "title": "Why is the alphabet in the order it is in when it could have been in any order when it was first made? Who decided that order?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djxx9xg"], "text": ["It was the ancient [Phoenecians]( URL_0 ) IIRC. * A comes from [\"Aleph\"]( URL_2 ) (meaning ox). * B Comes from [\"Bet\"]( URL_1 ) (meaning house). Probably the most important stuff got letters before other stuff. Oxen and houses were very important back when the alphabet was invented."], "text_urls": [["https://en.wikipedia.org/wiki/Phoenician_alphabet", "https://en.wikipedia.org/wiki/Bet_(letter\\)", "https://en.wikipedia.org/wiki/Aleph"]], "score": [3]}}, {"q_id": "6m04bs", "category": "Repost", "title": "If the universe is constantly expanding, what exactly is it expanding into?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djxw9xw"], "text": ["Nothing. Space itself is created faster than light moves, so we will also never know. It's crazy, but it's \"the end of the world\""], "text_urls": [[]], "score": [3]}}, {"q_id": "6m0hli", "category": "Repost", "title": "If water, electricity etc are considered basic human rights, why are people charged for them and companies can shut down your utilities if you can't pay?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djxyqmh", "djxz2np", "djy0bgp"], "text": ["Water is more than a basic human right, it's essential for your survival. However, clean water piped directly in to your home is not a human right, and when you pay for water, that's what you're paying for: the convenience. You can dig a well and get fresh water that way. What if you live somewhere you can't do that? Move, as people did before the modern age. As for electricity, it's not a human right at all. Many survive just fine without it, some by choice.", "Just so we are all grounded. Where does it say anywhere that these things are basic human rights? I'm not denying that water is a necessity, but where is it written that it's a right?", "The UN resolution talks about having **access** to water and sanitation as basic human rights. The objective is to foster cooperation between nations so the poorer countries can have access to means and methods to provide for their populace. > Calls upon States and international organizations to provide financial resources, capacity-building and technology transfer, through international assistance and cooperation, in particular to developing countries, in order to scale up efforts to provide safe, clean, accessible and affordable drinking water and sanitation for all It doesn't mean it has to be free or even subsidized. The resolution doesn't say anything about electricity."], "text_urls": [[], [], []], "score": [7, 5, 3]}}, {"q_id": "6m27c2", "category": "Repost", "title": "Why can't the human eye see clearly underwater, but with swimming goggles we can?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djyblsf", "djybj6e"], "text": ["Wait, people can't see clearly under water? This is a serious question, because under water I see as well as I do normally with my glasses.", "The human eye has evolved to see in air, and water has a different [index of refraction]( URL_0 ) from that of air. Swimming goggles trap air in front of the eyes, so you're seeing through air before water."], "text_urls": [[], ["https://en.wikipedia.org/wiki/Index_Of_Refraction"]], "score": [4, 3]}}, {"q_id": "6m36xw", "category": "Repost", "title": "- Why are all the bottoms of clouds have a flatness about them while the tops are very non uniform?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djykb6f", "djykahr"], "text": ["Think about a bubble bath. All the foam is very irregular on top, but flat on the bottom. The same happens to clouds. When the air parcel reached a level where it can exist (defined by pressure, temperature and humidity), then it condensates and the clouds is formed. The interface separating the \"here you can exist - here you can't\" is the flat bottom. Same as the bubbles can't exist below the water, but exist above, and the interface is flat.", "Below a certain height it's too warm and there's too much air pressure for cloud vapor to form. Once you pass that barrier the vapor forms freely and thus gives the upper portions of the chaotic, fluffy appearance while the vapor vanishes below the point where it physically can't exist, giving the bottom a reasonably smooth appearance."], "text_urls": [[], []], "score": [63, 6]}}, {"q_id": "6m46ch", "category": "Repost", "title": "How come radio station frequencies don't end in even numbers?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djyt738"], "text": ["Due to FCC regulations to reduce interference between radio stations. Radio station can only occupy roughly 88MHz to 108MHz. To fit as many stations as possible within that band, and reduce any possible interference, stations have to be 200 KHz apart, and it was decided to be every odd number instead of even just because. There wasn't a real reason to make it odd, other than with the 200KHz spacing it would make them either odd or even and the FCC just chose odd. I believe Europe is only spaced 100KHz apart, so you can have odd and even stations there. Quick edit: This applies to FM, as AM can be even or odd. Found a link that basically says the same as I did. URL_0"], "text_urls": [["http://electronics.howstuffworks.com/fm-station-odd-number.htm"]], "score": [3]}}, {"q_id": "6m5857", "category": "Repost", "title": "How does a handicap in golf work? What do the handicap numbers for each hole mean?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djyzm8y"], "text": ["Each golf hole has a \"par\" score, the number of strokes an excellent golfer should need top play the hole. Some holes are harder than others, and each course ranks its holes from 1, the hardest, to 18, the easiest. When a person has a 7 handicap, they are allowed to subtract 1 from their score on the holes with handicap numbers 1 through 7. Golfers with handicaps can then compare their \"net\" score on each hole fairly."], "text_urls": [[]], "score": [3]}}, {"q_id": "6m5a6a", "category": "Repost", "title": "Why do you blow on a fire to help it grow, but you blow to put out a candle?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djz1ocv"], "text": ["To have fire you need 3 things: oxygen, fuel and heat. When you're blowing on a fire, you're adding oxygen. When you're blowing out a candle, you're removing enough heat for the flame to extinguish."], "text_urls": [[]], "score": [3]}}, {"q_id": "6m6akn", "category": "Repost", "title": "Why does cold water seemingly taste better (or seem more enjoyable in general) than warm water?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["djzaccu"], "text": ["As discussed on /r/askscience recently , your body is constantly making heat and has to dispose of that. \"Room temperature\" is the comfortable temperature at which your body (at rest) is in equilibrium and doesn't need to do anything special to make or shed excess heat. At warmer ambient temperatures, sweating will be required, or other ways of cooling off. If you drink cool liquids, this will help cool your body and reduce the amount you need to sweat. As with many things, \"tasting good\" is a signal from the brain that the food/drink is particularly useful/needed at the time. For similar reasons, sports drinks will taste really good after you've sweated a lot - because they replace lost electrolytes and provide sugar to replenish your blood sugar levels quickly - but will taste overly salty if taken after a meal or other point when you aren't short on electrolytes. On a cold winter's day, you will probably find that cold water isn't that \"tasty\" - but a cup of hot tea or coffee certainly is. These hot drinks are just shortcuts to warming you up without having to increase your metabolism / burn extra calories. So your brain will signal that these taste good."], "text_urls": [[]], "score": [5]}}, {"q_id": "6mcjms", "category": "Repost", "title": "How did our ancestors survive without glasses?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dk0kwka"], "text": ["Bad eyesight is not, in and of itself, a detriment to reproduction. For example, I need glasses. I'm near-sighted. But it isn't so bad that I need to wear glasses all the time; only when I'm driving and need to read street signs is it really necessary. I can get around my city without a problem because I already know the layout of the streets, but when I go to neighboring cities I sometimes will need to read the names of streets, so I bring my glasses. Primitive lifestyle didn't have tiny letters to read that would affect their survival. Only the most severe bad eyesight would be of any real effect. This means all the people with only slightly bad eyesight would continue to be able to provide for their families and reproduce just fine."], "text_urls": [[]], "score": [3]}}, {"q_id": "6mf7ob", "category": "Repost", "title": "What exactly is the Publishers Clearing House? And how do they have so much money to give away?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dk12utn"], "text": ["They're a seller of magazine subscriptions. Magazine publishers, love subscriptions enough they'll pay other businesses to generate them (that's the same reason some retailers try to give you a trial subscription to a magazine when you make a purchase). They sell magazine subscriptions for revenue. Rather than paying millions of dollars per quarter for lots of television ads, they do fewer ads, and a sweepstakes."], "text_urls": [[]], "score": [4]}}, {"q_id": "6mia52", "category": "Repost", "title": "why is coffee called joe?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dk1umjx"], "text": ["There are two strong ideas but neither is verifiable. 1. A corruption of one of the slang words for coffee; **jamoke** (a compression of java and mocha). So **\"cup of jamoke\"** transitioned its way to \"cup of Joe\" or \"cuppa-Joe\". 2. *Joe* is jargon for \"fellow, guy, chap\" and so \"cup of joe\" means \"common man's drink\" or **\"cup of Joe's drink\"** (average Joe, etc). [Source: Snopes]( URL_0 )"], "text_urls": [["http://www.snopes.com/language/eponyms/cupofjoe.asp"]], "score": [11]}}, {"q_id": "6mm8ct", "category": "Repost", "title": "Why do we enjoy/prefer music with lyrics that rhyme?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dk2nhy7"], "text": ["When you're reading or listening to something that rhymes, it sets up an expectation that is then fulfilled. It's something you're actually trained to expect; rhyme is not an automatic function of poetry (Old English poetry, for example, was heavy on alliteration but didn't rhyme at all). The best way I can demonstrate how that expectation/satisfaction works is to show you how odd it is when it's frustrated. Take a look at a poem titled \"Strange Meeting,\" by Wilfred Owen: URL_0 What drives you slightly crazy about it is that it employs pretty much only \"slant rhymes\" - words that *almost* rhyme but don't, really. You'll find here that he likes to match consonants but not vowels on the \"rhyme\" words. The technique has a disquieting effect, because it's toying with and frustrating the expectation of rhyme."], "text_urls": [["https://www.poetryfoundation.org/poems/47395/strange-meeting"]], "score": [4]}}, {"q_id": "6mpnhc", "category": "Repost", "title": "Why do spider's legs curl up when they die?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dk3dga4"], "text": ["Took this fun answer from an older question of the same topic answered by u/MorphingShadows. Not my own work before the fearsome pitchfork folk attack. \"When spiders die, they typically curl their legs under them. Spiders don't possess muscles like that of insects and other animals, but instead what some would describe as some weird ass hydraulic system; fluid is forced to extremities, sort of like having eight penises for legs and getting boners instantaneously to walk around. So when a spider dies, its limbs essentially lose pressure and all sort of wind back up. Spiders suffering from dehydration will have trouble moving for this reason and sit in a similar fashion.\""], "text_urls": [[]], "score": [5]}}, {"q_id": "6mpo0v", "category": "Repost", "title": "How do cranes get set up?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dk3dlun"], "text": ["It is awesome. They build themselves. Here's a an animated gif: URL_0 Here's a gif from actual footage: URL_1"], "text_urls": [["https://m.imgur.com/t/the_more_you_know/dTSHCNY", "http://i.imgur.com/kNHt5Ww.gifv"]], "score": [10]}}, {"q_id": "6mtn4q", "category": "Repost", "title": "Why do humans only crave for two tastes - salty (e.g. Chips) and sweet (e.g. Soda, cake, ice cream) and do not crave for other tastes (bitter, umami)", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dk47f9i"], "text": ["You also sometimes crave fat if you have been active for some time. You also crave water when you are thirsty. And sometimes you do crave a juicy steak, a burger or some tomato as they are rich in umami. Alcohol is also something you crave sometimes. You never crave bitter things as that is not something you need but something you should stay away from. Being bitter or sour often means the food is rotten or otherwise spoiled. Salt is also somewhat of a double sword as you may sometimes crave salt and sometimes avoid it at all cost depending on your sodium levels. The human body does a good job at trying to keep your meals balanced and taste is playing a big part in this. The problem for modern humans is that we have not developed any systems for craving vitamins and minerals as this have generally not been a problem until now. We also have our hunger system tuned to be hungry most of the time as eating too much have not been a big problem and generally a good idea to stay alive. Historically it also takes a lot longer from becoming hungry and starting to prepare meals to being able to eat."], "text_urls": [[]], "score": [4]}}, {"q_id": "6mtxv3", "category": "Repost", "title": "So I've heard of a photographic memory, but I've never known how it really works. So how does a photographic memory work? And how does a person know if they have one?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dk4aplw", "dk49q24"], "text": ["See [Eidetic memory] ( URL_0 ): that's what a small number of people actually have, while purely \"photographic\" memory hasn't actually been found in the real world. With Eidetic memory, images form only part of the experience and aren't remembered perfectly, but other senses form part of the memory. In *The Big Bang Theory*, Sheldon is naturally very clear about the difference.", "I have a photographic memory but it was only a few years ago I found out my memory was different from everyone else's I believe it's just something you are born with, I can remember many things in perfect detail from when I was around 3 years old, I can remember the day of the week on a specific day and what the weather was like. I can even remember my best friend's card PIN number from glancing at it ages ago LOL. I'm starting to develop my memory and I'm about to try to memorise a pack of cards and remember pi to as many digits as I can :D It can be tough sometimes, with any bad experiences you have you will always remember in such detail it can get you down sometimes but I do love having a photographic memory and I find it very intriguing. Can most people remember their 16 digit card number? For some reason everyone I know seems to not have memorised their credit card info and I find it crazy since it's just a handful of numbers"], "text_urls": [["https://en.wikipedia.org/wiki/Eidetic_memory"], []], "score": [3, 3]}}, {"q_id": "6mucok", "category": "Repost", "title": "How do we have cures for so many of the worlds major diseases yet something as common and mostly harmless as the common cold is yet to be cured?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dk4cwx5"], "text": ["Which cold do you want a cure for? The common cold is the name for a large number (hundreds) of similar viruses that like to hang out in your nose and throat. And like the flu they also mutate rapidly, meaning each year it is a slightly *different* set of hundreds of viruses to defend against."], "text_urls": [[]], "score": [8]}}, {"q_id": "6mvm1u", "category": "Repost", "title": "What is a DNS address and why is it important?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dk4nvra"], "text": ["The DNS, or Domain Name System, is basically the phone book of the internet. Every computer that is connected to the internet has what is known as an IP, or Internet Protocol, address. This looks something like this: 123.456.789.012. What each one of those numbers means is beyond the scope of ELI5, but it basically allows your computer to know how to connect to the webserver that you are trying to connect to, just like how dialing (555) 555-5555 will connect you to the phone that you want to connect to. The problem is that remembering that string of numbers is hard - you don't know the IP address of Reddit or Facebook or Google off the top of your head. In order to make the internet easier to use, we instead type in URLs, or Uniform Resource Locators. That is what you think of when you think of a website - URL_0 is a URL. The DNS is basically the middle man between the URLs and the IPs where the servers physically are. When you type in URL_0 , it queries one of the central DNS servers and obtains the IP address that is assigned to that URL. Your computer then connects to that IP address to retrieve the content you are after. Now, in practice your local ISP may cache the most common IPs just to speed the process along, but the DNS servers are still the servers that hold the master list of URL to IP mappings."], "text_urls": [["http://www.reddit.com"]], "score": [5]}}, {"q_id": "6mvmo1", "category": "Repost", "title": "How do companies that operate as basically monopolies not get into trouble in the US?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dk4o4xp"], "text": ["it is not a crime to be a monopoly. it is a problem if you actively prevent a fair market. In your example, the simple fact is that broadband service has enormous startup and fixed costs. its rarely practical to bury two fiber networks and split the revenue. The fact that it doesn't make financial sense to challenge the incumbent is not the incumbents fault. You cant force someone to compete. Often times these situations will become a utility, at which point the local govt will protect their monopoly status, but in return, they get a say in how the business runs, prices, ect, to ensure they are not exploiting their status. So far, this hasnt happened with broadband, because they fight it... but it will probably happen eventually. Or 4g/5g/6g whatever will eventually supplant the buried cables and the whole model changes. Im ignoring claims that comcast does supress fair competition, blocking access to utility poles and such."], "text_urls": [[]], "score": [3]}}, {"q_id": "6mwzyv", "category": "Repost", "title": "What is actually happening when you \"crack\" your knuckles? Why do you have to wait a bit of time before you can do this again?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dk4zkx1", "dk53epa"], "text": ["When you pop a joint, you're stretching the joint capsule. The cracking sound is the popping of bubbles made up of gases within the synovial fluid, the fluid that surrounds our joints within this capsule. You have to wait awhile because the gases need time to build up again.", "A lot of people are going to say that it's from the popping of gas bubbles in your joints and that you have to wait for the gas bubbles to reform to pop them again. This is what originally was was thought to happen but new evidence suggests THIS IS NOT THE CASE. In fact it is practically the reverse. The popping sound you hear is a gas cavity forming in your joints. This is due to the negative pressure (aka like a vacuum) that happens as you pull on your finger (joint). The nitrogen dissolved in the fluids suddenly forms a bubble in your joint (this is due to how pressure affects that state of matter but that's a different topic). This releases energy and thus the pop. Until the gasses dissolve again into the fluid, you can't form this bubble again to get the sound. [video of the gas cavity forming]( URL_0 ) [source of information]( URL_1 )"], "text_urls": [[], ["https://youtu.be/_ZNENkkf5Uw", "https://www.wired.com/2015/04/watch-gross-mri-knuckle-cracking/"]], "score": [31, 4]}}, {"q_id": "6mxxir", "category": "Repost", "title": "Why can other animals (such as lions and wolves) eat almost only meat and remain healthy while humans have to eat a mix of meat, fruit, and vegetables to remain healthy?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dk59px6"], "text": ["Essentially it has to do with differences in enzyme expression. Enzymes are little machines in the body that help break down and convert the food we eat into other forms that we can then get energy from or help with growing cells and other bodily functions. For example, other animals (not including humans, and for some odd reason, guinea pigs) have an enzyme that allows them to produce their own vitamin C, while humans don't have this enzyme. Therefore, when humans don't get vitamin C from the diet, we get a disease called [scurvy]( URL_0 ). Because humans lack some of the enzymes that other animals have, we have to get nutrients that the enzymes would otherwise produce from our diet."], "text_urls": [["https://en.wikipedia.org/wiki/Scurvy"]], "score": [3]}}, {"q_id": "6mytz8", "category": "Repost", "title": "How do modern touch screens know to only work when skin touches them, compared to when some other foreign material does?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dk5f29l", "dk5eyxv"], "text": ["I think it has something to do with completing a circuit. But fun fact, dog noses and paws work too.i learned that from my puppy.", "I'm by no means an expert here. So if I am wrong, someone please correct me. My understanding is that our fingers complete a circuit, having electricity pass through it. That's why stylists also work, and some random materials but not others. Has to do with conductivity."], "text_urls": [[], []], "score": [3, 3]}}, {"q_id": "6mzt2z", "category": "Repost", "title": "Why do humans like music ?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dk5nakl"], "text": ["Melody and rhythm can trigger feelings from sadness to serenity to joy to awe; they can bring memories from childhood vividly back to life. From an evolutionary point of view, however, music doesn\u2019t seem to make sense. Unlike sex, say, or food, it did nothing to help our distant ancestors survive and reproduce. Yet music and its effects are in powerful evidence across virtually all cultures, so it must satisfy some sort of universal need. Music triggers activity in the nucleus accumbens, the same brain structure that releases the \u201cpleasure chemical\u201d dopamine during sex and eating. Animals get that same thrill from food and sex, but not, despite the occasional dancing cockatoo, from music."], "text_urls": [[]], "score": [4]}}, {"q_id": "6mzx9n", "category": "Repost", "title": "Why is something like steak able to be eaten more acceptably whilst undercooked while something chicken isn't?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dk5nc6r"], "text": ["Chicken and pork are likely to carry diseases, specifically salmonella and trichinosis. Steak and fish are less likely to have disease, so rare steak and sushi are safe as long as they're sourced properly."], "text_urls": [[]], "score": [6]}}, {"q_id": "6n22qb", "category": "Repost", "title": "Why when doing exercise do you tire relatively quickly, only to recover and regain stamina to continue? What causes this \"second wind\" effect?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dk65bb8"], "text": ["Respiration. When you exercise, your body respirates to keep your muscles going; this requires oxygen and is called aerobic respiration. When there isn't enough oxygen coming in, your body will start anaerobic (without oxygen) respiration. This is highly inefficient and causes lactic acid to build up in your muscles (which makes your muscles feel tired). Once you've rested, you start to aerobically respirate again, which makes the lactic acid go away. Once its gone, your muscles don't feel as tired, so you get the \"second wind\". This pattern keeps repeating. (I'm only 14 so I might be wrong)"], "text_urls": [[]], "score": [7]}}, {"q_id": "6n23f1", "category": "Repost", "title": "Why do we in the US use inches, feet, yards, etc to measure most things, but centimeters to measure very small things when we largely reject the metric system?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dk639ux", "dk644l7"], "text": ["The metric system is used in most scientific fields in the US, as well as a range of other fields, such as the military and some manufacturing. You use inches and feet for others because a lot of people in the US were against switching everything over to metric.", "This can be seen as the seeping of European and other manufacturing standards seeping into the everyday life of the U.S. Especially at places like IKEA, things are designed and manufactured in metric, then would have to be converted to Imperial for an American audience. More and more, they're skipping that conversion step and just shipping the original measurements."], "text_urls": [[], []], "score": [6, 3]}}, {"q_id": "6n2tro", "category": "Repost", "title": "How come that a negative multiplied by another negative becomes a positive?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dk6a1ge"], "text": ["The opposite of the opposite is back to normal. If you turned something inside out twice, it would be back to normal. Same as if you turned it around twice. On a number line, the number 5 is five units to the right. If you do the opposite of that, you go left 5, to -5. If you go the opposite of left five (the opposite of the opposite) you're back at 5."], "text_urls": [[]], "score": [3]}}, {"q_id": "6n2tse", "category": "Repost", "title": "USA voting system.", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dk69tjd", "dk6d4b2"], "text": ["No issues are voted on by all US citizens. The United States is a \"representative democracy\". US citizens vote on members of Congress to represent them, and make/change laws on their behalf. Even with the presidential election, citizens are voting for who will be appointed as the electors to cast their states' votes for president.", "Because collectively, US citizens are ignorant and apathetic. What do you know about forestry? Civil engineering? Pollution mitigation? Soybeans? Nuclear power? Migrant workers? Economics? Computer security? Syria? Traffic planning? Fracking? Epidemiology? And are you willing to spend most of your time educating yourself about these and other issues? If not, congratulations, you are ignorant and apathetic too. Most of us are. As much as we like to denigrate our politicians, this is their job. The work full time have staffs to ensure they understand the implications of bills they are voting on. Without that, you would have chaos. You likely won't fully understand what you are voting on, and what is worse, you will only vote on what you care about. Why everyone else was jumping on the \"Prevent Puppy and Kitty Cruelty Act\", the \"Adhesives in Particle Board Regulation Act\" just make it like to use lead and plutonium based building materials legal in new construction, because it look to boring to most people."], "text_urls": [[], []], "score": [10, 3]}}, {"q_id": "6n5r1n", "category": "Repost", "title": "How Check Kiting works", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dk6ypyj"], "text": ["There is a lag between when a check is cashed and the payment is finalized. If you write a check from an empty account and then immediately deposit a check for the same amount from another empty account, when the first check goes to clear it looks like you have enough money to make the payment, when in reality you don't and you're just moving a floating charge from account to account. This can go on until: 1. The bank figures out what you're doing 2. Eventually you run out of accounts to float to and your last check bounces 3. You get some actual money (such as a paycheck) into the accounts, this covering up what you did"], "text_urls": [[]], "score": [3]}}, {"q_id": "6n5rnq", "category": "Repost", "title": "What causes computer components to heat up during use?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dk6yo1p"], "text": ["Resistance. It's essentially the electrical equivalent of friction. Any current going through a wire is going to be less than 100% efficient - that loss happens as heat."], "text_urls": [[]], "score": [4]}}, {"q_id": "6n7ei8", "category": "Repost", "title": "- why do we sweat when we eat really spicy food.", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dk7cbkl"], "text": ["You don't have a \"hot/spicy\" taste receptor. Capsaicin oil, the chemical that makes things taste spicy is actually doing so by triggering the heat receptors in your mouth that normally tell you if food is physically hot. The exact opposite of effect is triggered by Menthol, which chemically triggers the cold receptors."], "text_urls": [[]], "score": [4]}}, {"q_id": "6n7f8e", "category": "Repost", "title": "Why does certain food have to be refrigerated after opening?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dk7byst"], "text": ["When many types of food are packaged, it's done under sterile conditions - so that bacteria or fungi can't grow in it. As soon as you break the seal of a package, you introduce bacteria or fungal spores into the food. At room temperature, microorganisms like to thrive. At refrigerator temps, it slows or stops the growth of these microorganisms. Not all types of them, just most."], "text_urls": [[]], "score": [13]}}, {"q_id": "6n8f0h", "category": "Repost", "title": "Why bugs shrink their legs to the middle when they die?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dk7io1p"], "text": ["Sorry for my English. Spiders' legs are moved by their Blood or something close to Blood. They are hydraulic. If u kill spider, hydraulic preasure goes down and then you See described effect."], "text_urls": [[]], "score": [6]}}, {"q_id": "6n99h1", "category": "Repost", "title": "Why do we as humans have to keep our teeth clean, whereas other animals do not?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dk7r5hz", "dk7t9b1", "dk81c7v", "dk899my", "dk7o83n", "dk7ob18", "dk84dho"], "text": ["Animals will eat until their teeth have been ground down and then slowly starve to death, or at least get so weak that they get ripped to shreds by predators or succumb to disease they have no medicine for. Humans prefer to die of other things. Also we eat way more sugar.", "Until refined sugar became available a few hundred years ago, we really didn't need to worry about keeping our teeth clean so much. Your dentist is not lying- sugar REALLY is bad for teeth. Teeth don't last forever, but most people kept thier choppers until they died. Fun fact: When refined sugar was introduced to Europe it was expensive and lower classes could not afford it. Rotten teeth was sometimes a badge of honor for the nobility as it advertised the fact they were rich.", "Sugar. That's about it. When we evolved, we got basically no cane sugar. Or high fructose corn syrup. We'd occasionally get some fresh fruits or even jams or preserves, or honey. But it was fairly rare, and the sugars in fruits were eaten with lots of fibers as well. Once we started getting refined cane sugar around the 1600s thanks to slave plantations in the west indies and Brazil, we started to put that shit on everything (if we could afford it). And we didn't really need to brush before (maybe just floss to get some meat out). But those sugars were great for the bacteria that lived in our mouth and on our teeth and gave them an exponential boost. But the short of it is: processed foods and sugars (as we still put sugar into all kinds of food today - just look at the ingredients list on things like bread: it almost always also has sugar in it).", "Sugar is a fairly obvious answer and has been well covered, but there are additional answers - for one, we don't replace our teeth (beyond our milk teeth). Some animals like sharks simply have an endless conveyor belt of new teeth, whilst in gnawing rodents (rats, hamsters etc) the teeth permanently grow (think fingernails or hair) and as such they need to grind them down constantly. The fact we have exactly one adult pair of teeth for our lifespan means we have to clean them whilst for some animals teeth are as transitory as toenails. Second point, which is kind of linked to the first is lifespan. Compared to most living animals, humans have a capacity for exceptional lifespans. 60-80 is a standard range even for \"wild\" humans, provided they survive the early years (and bearing in mind a slightly higher % of death year by year as a result of injuries that could otherwise be healed etc). Given our teeth are expected to last a good 60 years (70 year lifespan, milk teeth assumed to be gone by 10 for ease of maths), this is ridiculously long compared to say a horse, or a cow. (25-30 and 18-22 respectively). With modern technology this can easily be a 85 year lifespan for our teeth to function, with no replacement. As such, especially bearing in mind our modern sugary diet, teeth represent a \"weak link\" for retaining full health. Given humans tend to breed at 15-30 (especially \"wild\" humans, especially females (males likely are more like 20-40 average range), our teeth function just fine up to that age, especially in the wild. Past that point we've already bred, there's very little selective pressure to actually force us to get \"better\" teeth. One final point - some people mentioned that many wild animals die when their teeth decay to nothing, and this is true. However, humans are heavily social animals, even since we weren't even humans (Neanderthals). We have records of us caring for injured, crippled, or weakened members of the group, which means a person could easily enough survive without teeth, on a diet of soft boiled food or broth.", "Because we have a diet that has lots of processed food and refined sugar added, with varying types of food items, traditionally in the wild carnivors eat only meat, and the herbivores only eat a limited plant diet.", "Humans have artificially extended lifespans, and also have a diet that contains far more sugar than other species. The human species, before medical advancements and nutritional awareness, had a lifespan that was typically around 40 years. Humans also had a diet that comprised primarily of meats and vegetation, with no processed food. As a result, the teeth in an adult lasted a sufficient time with no cleaning to allow for a full lifespan. Nowadays, we consume sugar regularly, which is a breeding ground for bacteria in the mouth. We also live to 70 years old or more, well beyond the original \"rated lifespan\" of teeth. So we have to keep our teeth clean to make sure they last.", "Do animals eat Sour Patch Kids and drink 32 ounce Mountain Dews on the reg?"], "text_urls": [[], [], [], [], [], [], []], "score": [65, 24, 19, 7, 4, 4, 3]}}, {"q_id": "6nac8q", "category": "Repost", "title": "How does a home scale tell you your body fat %, body composition, etc.", "title_urls": {"url": []}, "selftext": "Really curious how just standing on the scale can tell you those things and how accurate they really are.", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dk7xjzi", "dk85ulr", "dk7xcat", "dk7xfsf"], "text": ["Your scale is running a small electric current into your feet - up one leg and down the other, and measuring how much voltage this takes. From the voltage it can calculate the resistance/conductivity of your flesh. Fat flesh has a different conductivity than lean flesh does, so from your conductivity it can tell you your body fat percentage. It's not the most accurate measurement, since it only measures the conductivity of your legs, not your entire body. And unless you have an absolutely top-of-the-line bathroom scale, the sensor is probably not very high quality. But it can be useful as a ballpark figure.", "This question is very popular on ELI5 and has been answered countless times: URL_3 URL_1 URL_2 URL_4 URL_0", "The scale sends a mild electric current up one leg, and measures the resistance when it comes out the other. It does some fancy math, knowing that muscle conducts electricity better. In the end, you're left with an inaccurate measurement of body fat.", "The fancier ones send a very very light electrical pulse through your feet. The level of resistance it records is usually a pretty good indicator of body composition (though there are a ton of environmental factors). Try standing on it with wet and then dry feet to see a difference. The fancier ones will ask you to input your height and make a user profile, this makes it more accurate. So the accurate answer is usually \"depends what you need it for\" I'd add a +- 5% just to be sure (especially if you didn't put in your height)."], "text_urls": [[], ["https://www.reddit.com/r/explainlikeimfive/comments/3c3ub4/eli5_how_do_scales_measure_water_percentage_body/", "https://www.reddit.com/r/explainlikeimfive/comments/2nwrzi/eli5how_do_bathroom_scales_that_calculate_body/", "https://www.reddit.com/r/explainlikeimfive/comments/6gro2h/eli5_how_do_modern_bathroom_scales_measure_the/", "https://www.reddit.com/r/explainlikeimfive/comments/2r1h1s/eli5_how_does_me_standing_on_my_bathroom_scales/", "https://www.reddit.com/r/explainlikeimfive/comments/2ejdkr/eli5_how_does_the_bmi_function_on_my_bathroom/"], [], []], "score": [9, 4, 3, 3]}}, {"q_id": "6nax71", "category": "Repost", "title": "Why is it that we occasionally see words that we view fairly often as strange and unusual, almost as if we've never seen them before?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dk8371x"], "text": ["It is called semantic satiation. If you look at or hear a word repeated, you stop experiencing it as a word and start seeing it as an arbitrary group of letters or sounds, that has no inherent relationship with what the word represents. \"Dog\" is no longer man's best friend, it because a wierd string of squiggling we for some reason associated with the animal."], "text_urls": [[]], "score": [3]}}, {"q_id": "6nb6j4", "category": "Repost", "title": "Why are hangovers so much worse as we get older?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dk84od8"], "text": ["Even at 25, we aren't as young as we used to be. It'll only get worse from here. The key is to stay hydrated. Often times when we forget to drink \"real\" water and might only be drinking liquor the whole night. I've found that about one cup of water for every \"drink\" helps a lot. In addition, these days I try to never go to sleep drunk. If possible, I stop drinking about an hour or two before going to bed to give me time to sober up and drink the water."], "text_urls": [[]], "score": [5]}}, {"q_id": "6nbtxb", "category": "Repost", "title": "Why do websites in asian languages typically seem \"cluttered\"?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dk8a9pb"], "text": ["You're not the first to ask. People seem to think it's because of cultural reasons, and an emphasis on text over large graphics due to historic technical limitations. URL_0 URL_2 URL_4 URL_3 URL_1"], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/1qjuom/eli5_why_is_japanese_web_design_stuck_in_the_late/", "https://digitalcommunications.wp.st-andrews.ac.uk/2016/03/03/why-is-eastern-asian-web-design-so-busy/", "https://www.reddit.com/r/explainlikeimfive/comments/44azgm/eli5_why_are_all_asian_websites_so_horrifically/", "https://randomwire.com/why-japanese-web-design-is-so-different/", "https://www.quora.com/Why-does-the-design-of-Japanese-websites-tend-to-differ-from-those-in-the-US"]], "score": [5]}}, {"q_id": "6nct5e", "category": "Repost", "title": "How does google search the entire internet so fast when my computer takes ages just to search its own files?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dk8i3hf"], "text": ["Google isn't searching files, it's browsing a tagged index, have a [video] ( URL_0 )"], "text_urls": [["https://youtu.be/gIPIqOiSknY"]], "score": [8]}}, {"q_id": "6ncz4x", "category": "Repost", "title": "What are the differences between Advil, Aleve, Aspirin, and Tylenol, and what problems does each one treat best?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dk8jmsh", "dk8jnr3"], "text": ["Advil is Ibuprofen. Aleve is Naproxen Sodium. Tylenol is acetaminophen. Aspirin is... Aspirin. Acetaminophen is used for mild pain and fever, and is easily mixed with cold medication (by the manufacturer). It does not work for inflammation and overdose or abuse can lead to liver failure. Naproxen is a non-steroidal anti-inflammatory drug (NSAID), and can reduce pain, fever, swelling, and stiffness. Abuse can lead to stomach ulcers. Ibuprofen is also an NSAID, of similar class as Naproxen. Specifically, if is a go-to for menstrual cramping and migraines. As with Naproxen, it runs a risk of ulcers, but also has increased risk of heart failure and other problems. Aspirin is an NSAID, but also an antiplatelet. It is used in specific inflammation conditions, like Kawasaki disease, as well as in low-dosage heart regimens. It has a larger risk of ulcers. NSAIDs generally should not be taken together, if it can be avoided because of the bleeding risks. If you take a full dose of Aleve, wait for the full time for it to wear off before switching to Ibuprofen.", "Advil works well with muscle aches and, especially, toothaches. It can relax muscles. It can irritate your stomach. Aspirin is an anti inflammatory. It works with general pain and it is also a mild anticoagulant. As such it's good with any pain but it's also good to take a small dose regularly when older to reduce heart attack risk. It can irritate your stomach and cause ulcers potentially. If you are having s heart attack, chew an aspirin while you wait for an ambulance. It can reduce risk of damage to heart. You don't want to take it if you're at risk of stroke, though, because it can increase brain bleed chance. Don't give to babies and young children, usually Tylenol can help with general pain. It doesn't irritate your stomach. Can also reduce fever. It can damage your liver if you take too much or even if you've been drinking many alcoholic drinks before you take it. So if you're a drinker, don't use. If you have an irritated stomach or intestines, this is better to take. I'm not too familiar with Aleve."], "text_urls": [[], []], "score": [11, 5]}}, {"q_id": "6nd10l", "category": "Repost", "title": "Where do last names come from?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dk8jxgb"], "text": ["Depend. in Scandinavia men had the name of their father as surname (Leif Erikson mean Leif son of Erik) Last name could also come from profession (Potter, Baker, etc.) Can come from the city/town you come from (Chr\u00e9tien de Troyes, 12th century poet who's known for the arthurian legends) can even be a nickname your ancestor had that became officially his surname. All these examples are only from European surname. I don't know enough about other regions such as asia and africa to say anything."], "text_urls": [[]], "score": [5]}}, {"q_id": "6neb3z", "category": "Repost", "title": "What exactly is post-postmodernism?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dk8vlzd"], "text": ["This David Foster Wallace quote explains it beautifully: > For me, the past few years of the postmodern era feel a bit like the way you feel when you're in high school and your parents go on a trip, and you throw a party. You get all your friends over and throw this wild disgusting fabulous party. For a while it's great, free and freeing, parental authority gone and overthrown, a cat's-away-let's-play Dionysian revel. But then time passes and the party gets louder and louder, and you run out of drugs, and nobody's got any money for more drugs, and things get broken and spilled, and there's cigarette burn on the couch, and you're the host and it's your house too, and you gradually start wishing your parents would come back and restore some fucking order in your house. It's not a perfect analogy, but the sense I get of my generation of writers and intellectuals or whatever is that it's 3:00 A.M. and the couch has several burn-holes and somebody's thrown up in the umbrella stand and we're wishing the revel would end. The postmodern founders' patricidal work was great, but patricide produces orphans, and no amount of revelry can make up for the fact that writers my age have been literary orphans throughout our formative years. We're kind of wishing some parents would come back. And of course we're uneasy about the fact that we wish they'd come back--I mean, what's wrong with us? Are we total pussies? Is there something about authority and limits we actually need? And then the uneasiest feeling of all, as we start gradually to realize that parents in fact aren't ever coming back--which means we're going to have to be the parents. Basically postmodernism says all rules are made up. What counts as art is made up, the rules art has to follow is made up, the structure of human society is made up, right and wrong are made up, etc. It's all about tearing apart all the rules we used to follow and looking at the pieces through a microscope or just saying we don't need them. Post-postmodernism says \"well, maybe even if it is made up, rules and definitions are useful and worth keeping around and maybe we can even make up new rules.\" I'm sure somebody who studies this in depth will disagree, but that's probably an excellent understanding for a 5 year old."], "text_urls": [[]], "score": [8]}}, {"q_id": "6nh0ug", "category": "Repost", "title": "Why are insects so annoyingly good at avoiding my swat attempts?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dk9dots"], "text": ["The species & offspring whose nervous systems didn't emphasize maneuverability and fast reflexes were swatted into extinction long ago."], "text_urls": [[]], "score": [16]}}, {"q_id": "6nh4pi", "category": "Repost", "title": "How does a laser read a barcode?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dk9egnw", "dk9ehkn", "dk9er8z"], "text": ["> How does a barcode scanner work? > A barcode scanner picks up the alternating black and white elements of the barcode which follow a specific algorithm that is turned into a corresponding text string by the scanner. This information is then sent over to your computer by the scanner no different than a standard keyboard does. This string of text will populate where ever your cursor is on screen at that time. The white part reflects the laser while the black part absorbs it. That light is reflected back to the scanner, which has a sensor that detects that. Source: URL_0", "The laser is just there to illuminate the barcode. The laser is swept across the barcode very qucikly, and a photo-diode records the intensity of the reflected light. The white portions reflect more light than the black portions. The timing of when the laser illuminates white or black parts of the barcode is used to calculate the thicknesses of each line and their spacing, which is then decoded into numbers to be fed into the computer system to look up product information. Newer barcode readers don't use a laser or photo-diode, instead using just a normal camera.", "The space between the black lines indicate a character (letter, number, etc.). The laser bounces off the white, but not the black. The scanner then can judge the space between the reflected laser light. The reader sends this to a computer program that turns the spacing information into characters. The series of characters is associated with information in a database to which the scanner is linked. E.g. 2468753 = tomato; tomato = $1.00. Next time you see a barcode, note that there are (usually) characters below, often numbers. Those numbers are what the scanner \"sees\" when it measures the space between the reflected light."], "text_urls": [["https://www.barcodesinc.com/faq/?nav=ftr"], [], []], "score": [27, 18, 3]}}, {"q_id": "6nix81", "category": "Repost", "title": "How does \"phone data\" actually work? Do the phone companies save money by handing out less amount of data per month? Is there a limit?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dk9sgi8"], "text": ["The phone data, connection, 2G etc all are working thanks to Masters that are usually placed on top of the buildings (they cooperate with the owner of the building or the land, offering them sweet deals by letting them use the master. Secondly, each masters have different frequency output, less number = faster but less strong (cant last long) so distance it travels is little, thus it requires more masters that support that frequency to be build. 4G = Requires alot masters that are close. 3G = Is better but slower than 4G, but does work eveb at longer distances whereas 4G cant. 2G: It travels very far, but it can only give little amount of data (signals) it carries + takes longer time, thus, it is usually used for calling mostly if no 3G or better is available. So now, we come to data! Phone data is something companies add to limit abuse on the masters. They can be overloaded and cause overall of the speed much worser, it practically would mean \"why use WiFi when you got unlimited data everywhere?\" And so, all will think that way and use data instead of WiFi. When all of us use the data, we make masters to transfer tremendously big data, and each masters are in contact with each other, so if you focus to one thing too much, that one thing will affect others too, the load is divided to others but others will also suffer same thing, this will cause a 3G speed similar to a 2G speed or worser, and 4G speed into a 2G speed. Else, no, data is damn cheap, but if you add a limit that can be breached by paying more money, then less people will waste data. Else, bandwidth is no problem, but problem is on the masters that sustain to those loads. This isnt about 50,000 or 100,000 people, but millions of people over the country. This is why in the past, a unlimited 2G data was cheap, because the masters would not suffer those loads as data size itself is already little, it was alright + not many people were using it, as back then, we had phones not capable of multitasking, so in the background, it did not require constant connection 7/24 unlike todays smartphones. In sweden, until 2010 or earlier, there was unlimited data plan, but now nope. In some countries, unlimited data still exists, but there is most of the time \"fair usage policy\" tending to apply, burden into small texts so customers dont see it but company has proof that they did add it to the site IF things go too big up to attorney."], "text_urls": [[]], "score": [3]}}, {"q_id": "6nj8ej", "category": "Repost", "title": "What makes rechargable batteries rechargable?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dk9z6f6"], "text": ["A battery is ran by a chemical reaction. Actually, there are 2 chemical reactions, one at anode and one at cathode. The first one requires one electron to be able to happen, and the second one produces one electron. Have the electrons flowing between the 2 reactions through a wire and you will get an electrical current. The problem is that these reaction convert some substance A into B (actually, there may be more things that can be consumed, but this is ELI5). So, at some point, you will run out of A and the reaction can't continue anymore. Depending on what type of reaction is used, if you run a current in the opposite direction, B can be converted back to A and your battery is recharged. In other cases, the reaction is irreversible and running a current in the opposite direction can cause some side-effects. Explosions included."], "text_urls": [[]], "score": [3]}}, {"q_id": "6njd1j", "category": "Repost", "title": "Why were canned tuna do not spoil easily? Is it the can itself that preserves them?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dk9vn0f"], "text": ["Classically, food would be sealed in a can and then the whole can would be heated. Killing bacteria and enzymes inside the can. Which delays spoiling significantly. Because the can is sealed, new bacteria cannot get in, so the food is preserved."], "text_urls": [[]], "score": [3]}}, {"q_id": "6njk7n", "category": "Repost", "title": "Why does salt make food taste better?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dk9xfmu"], "text": ["Salt pulls water out of food, and since the body can taste salt it can also taste whatever the salt is mixed with, like soup, cheese, celery, or most other savory foods."], "text_urls": [[]], "score": [4]}}, {"q_id": "6njw1v", "category": "Repost", "title": "If cancer is just your body's cells, how can it kill you?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dka07vd", "dka0w62"], "text": ["By growing and growing and growing uncontrollably, growing into tumors that crowd out and kill cells that you need to actually survive. Cancerous cells are cancerous because they have a mutation that makes them divide uncontrollably, and *another* mutation that disables the part of the cell that's supposed to cause it to shut down and die if it detects serious damage to its DNA.", "If you've seen the Matrix Trilogy think of cancerous cells as Agent Smith, replicating uncontrollably until everything has been taken over by those cells and the body can't function anymore."], "text_urls": [[], []], "score": [9, 3]}}, {"q_id": "6nket4", "category": "Repost", "title": "How do taxes work?", "title_urls": {"url": []}, "selftext": "I've just graduated from high schools and I still have no fucking clue how taxes work.", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dka5gey", "dka7dn9", "dka4qmi", "dkag5qn"], "text": ["Income tax works like this: Your first X dollars are taxed at a specific rate. That's a plain percentage -- possibly 0%. Your next Y dollars are taxed at a slightly higher rate. Your next Z dollars likewise. If you do certain things the government wants to promote, you can pretend your income was lower. As an example, let's say the tax brackets are 0% up to $10k, 10% on the next $15k, and 30% after that. You made $50k. You bought an electric car for $5k, and that's tax deductible. So in your taxes, you write down your gross income: $50k. Then you subtract the $5k deduction for the electric car: $45k. Now you look at the first tax bracket. It's 0% up to $10k, so you take off up to $10k from your income, multiply that by 0%, and add it to the tax you owe. That bracket gave you $0 in taxes and accounted for $10k of your income. You still have $35k left, so you look at the next bracket. It takes up to $15k of your income, and that portion of the income is taxed at 10%, so it adds $1,500 to your taxes. You still have $20k left, so you look at the next bracket. That takes all your remaining income and taxes it at 30%, giving you another $6,000 in taxes. That handles all your income, so you just sum up the amount of tax from each bracket -- $0 + $1,500 + $6,000 \u2192 $7,500 total. There are other types of tax, but that's probably the one you're talking about.", "For the US: 1. You estimate how much tax you will owe when starting a job. This will mainly be based on whether you have any dependents (such as children). Your job will give you a form to fill out that does this for you. 2. That estimated tax gets deducted from each paycheck and sent to the federal, state, and local governments. Once per year, you file a tax return: 1. Your job will mail you your tax information, called W-2 forms. 2. Figure out your total tax liability (how much you owe the government) 2. Figure out how much tax credit you get (how much the government owes you) 3. Subtract the credit from the liability to find out how much tax you should actually be paying. 4. Compare the tax you actually owe to the estimated tax that was withheld in Step 2. 5. Figure out whether you underpaid or overpaid over the course of the year. If you underpaid, you owe the government more money. If you overpaid, you get a refund. 6. Repeat for both state and local. Protip: [Just use software to do it for you.]( URL_0 ) It'll ask you stuff like, \"Are you married?\" or \"Did you buy a house this year?\" or \"What does your W-2 say in box 3?\" and you just fill in the answers and hit \"submit.\"", "In the US when you get a job you fill out a tax form for the state and federal governments. Based on how you filled it out, a portion of your paycheck is withheld. Every year you need to fill out another form for both the state and IRS and you calculate how much you owed the government that year. If you overpaid (which is normal) the government sends you the difference. If you underpay, then you need to send them payment. If you work for yourself you need to pay up by April. There are additional forms for income related to capital gains (stocks and bonds). That only matters if you sell stocks during the year or get paid dividends.", "I'm going to assume you mean taxes as in income tax/the frenzy people get into about \"tax day\" (normally on/around April 15th) and \"tax return/refund\" that you hear people talking about. So here's the deal, baring some exceptions, every dollar you earn at a job is taxed. When you started working you might have been asked to fill out several forms, one of which might have asked you things like \"how many dependents do you have.\" Then it gives you a very rough (and usually very bad, more on this later) estimate of how much federal income tax you'll owe for the working year. So let's say it says \"we estimate you should withhold 15% of your wages for taxes\" and you say fine. Now, your paycheck is 15% less, but the important thing is you haven't lost any money. That 15% that they take--it's still there, it's still yours, you just don't have it *now*. (In a real paycheck there would be other deductions taken off too: social security, local taxes, etc.) Now around February-April, most people will **file** their federal taxes. This is nothing more than filling out a few pages of documentation to let the government know how much money you earned, so they can figure out how much money you need to pay. So you'll typically get some forms from your job around this time called the W2 that lists how much money you've earned, how much you've paid in taxes, and how much you've withheld for taxes. Let's say that the gross salary is 50k over the course of the year. Gross means absolute total, before any taxes etc were taken out. This is the theoretical amount you'd have earned if you didn't pay taxes, pay social security, etc. The US federal income tax system is one called a \"progressive tax\" system. Another tax system you might have heard in the news is called a \"flat tax\" system, which is also known as a \"regressive tax\" system. The flat/regressive tax system is simple to understand: you pay the same percentage of taxes no matter your income. So if the flat tax was say 10%, then your 50k income means you pay $5000, and someone's 500k income means they would theoretically pay 50k. This isn't actually a good thing because imagine a person earning 20k/year gross: for him paying $2000 in taxes is a huge amount of money leaving him with less to spend for necessities. For that rich guy making 200k, he'd pay 20k, which is the entire income of the poor guy, but he still has 180k left to spend on things like \"food\" and \"housing.\" Sales tax is a form of a regressive tax because poor people pay the same in taxes for that chicken that needs to feed his family for the entire week, whereas for a rich person the measly dollar or two in sales tax for the chicken is literally pocket change. Back to the income tax/progressive tax. The system is split into several brackets. I don't recall them off the top of my head, but let's say the following are the brackets: * From $0 to $30000 you pay 0% taxes * From $30001 to $50000 you pay 20% taxes * From $50001 to $100k you pay 30% taxes * Etc So back to your 50k gross income: this means that the money you earn up to 30k will **always** be taxed at 0%. It doesn't matter if you make 50k, 25k, 500k. The first 30k will always be 0%. The money you earned between 30k and 50k are now taxed at 20%, always and forever. So you do some math: you have $20000 left untaxed, and on that 20k (and **only** on that 20k) you will pay 20% on taxes. The total amount you owe is just added up from all the brackets. This is important to understand because every now and then you'll hear conservative talking points like \"I was given a raise which pushed me into the next tax bracket and now I take home less money because I pay more in taxes!\" which is 100% factually incorrect. Even if you were \"pushed into the next tax bracket\", the only additional taxes you would pay is the amount in only that next tax bracket, so unless that next tax bracket had a tax percent over 100% then it is impossible to pay so much more in taxes that you take home less money, due to income tax. Now when you do your taxes you might also hear people talking about \"deductions\". What are these? These are ways to make your income look \"less\" so that you pay less taxes overall. Remember that your gross income was 50k. If you support yourself (ie, your parents don't claim to support you) then you are allowed to take a personal deduction. Let's say this deduction is worth $5000. You subtract it from your gross income to get your \"adjusted taxable wage\", which would be 45k in this example. This would now lower your tax burden: the first 30k is still taxed at 0%, but now you only need to pay 20% on 15k for the next bracket, instead of 20% on the original 20k. There are quite a few ways to lower your tax burden. Donating to charity for example would lower it. I think you get a tax credit if you bought an electric car, so that lowers your taxable wage as well. I think first time home buyers get a credit as well. If you deposit money directly from your salary into a retirement plan (IRA, 401k, etc) then it lowers your taxable wages as well. Ok, so you now have figured out how much money you owe the federal government in income taxes. How do you pay it? Well actually, you've already essentially been paying it. Remember that federal withholding we talked about? That's money that has been set aside (withheld) from your paycheck to be used to pay federal income taxes. So after one year of working, let's say they have withheld a total amount of 10k from your wages, and now you figure out you only need to pay 5k in taxes. You fill out your forms and give the IRS a bank account for them to deposit the remaining 5k into. A couple weeks later you get a huge 5k \"bonus\" and you're happy and go out and buy a brand new car with this \"free money.\" Only that's not free money. That's money that you actually earned. That's money that you told the government to withhold for you to pay taxes with, but that extra amount you get back means that he government has withheld too much money and are just giving it back to you. This money was just sitting there this entire time, earning no interest for you, not letting you access it to buy things, etc. The best way is to actually sit down and do the math to figure out how much you'll need to pay, and tell them to withhold as close to that amount as possible, but this is a much harder subject to talk about."], "text_urls": [[], ["https://apps.irs.gov/app/freeFile/jsp/index.jsp"], [], []], "score": [40, 4, 3, 3]}}, {"q_id": "6nkli9", "category": "Repost", "title": "How come when a video is sped up it becomes higher pitch and lower pitched when slowed down?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dka5wwl"], "text": ["For the same reason as if it was an audio cassette tape. You are compressing the audio, effectively making it have more waves per second which is the same as having a higher pitch."], "text_urls": [[]], "score": [4]}}, {"q_id": "6nm53l", "category": "Repost", "title": "Why does communism ultimately always fail when put into practice?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkagsgu"], "text": ["It gives a single body of power to much power simply put. The government will regulate and see every part of your life wether you like it or not and this devolves into corruption."], "text_urls": [[]], "score": [6]}}, {"q_id": "6nmjc9", "category": "Repost", "title": "The fear of AI.", "title_urls": {"url": []}, "selftext": "AI would still be bound to a base instruction set, and it seems like we'd (probably) implement kill switches in their programming. And even if neither of those things turn out to be true, and sentient (artificial) life is created ... so what? Is it a fear of creating something or someone smarter than ourselves? I just don't get it.", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkal2vp", "dkamco0", "dkajjgd", "dkalszt"], "text": ["> AI would still be bound to a base instruction set, and it seems like we'd (probably) implement kill switches in their programming. The problem with AI is that *we can't program it*. Consciousness is far too complex a thing for us to even understand, let alone program. The only possibilities being explored to create true AI involve things like self-learning neural nets. Which means that when the AI is finally complete, we'll have no idea what its programming is, nor do we really even have any way to fully understand it. > And even if neither of those things turn out to be true, and sentient (artificial) life is created ... so what? > Is it a fear of creating something or someone smarter than ourselves? I just don't get it. Think of it this way. If we can create an AI that's smarter than ourselves, then that AI could create another AI smarter than *itself*, which could create another AI smarter than **itself**. Very rapidly, we'd be faced with a super-intelligence whose thought process are beyond our ability to comprehend (much like your dog could never comprehend the complexities of your thoughts). We'd have no way to know if such a super-intelligent AI is benevolent or malevolent. Will it want to help us, or destroy us? And even if it wants to help us, will it help us in ways that we can tolerate? You're only \"helping\" your dog when you have it spayed or neutered, but your dog isn't particularly pleased with the outcome.", "That's a popular question here. I hope ye find these previous posts helpful. 1. [ELI5: why Is It Considered Dangerous to Create...?]( URL_4 ) 1. [ELI5: Why Are We So Scared of Ai...?]( URL_1 ) 1. [ELI5: Why Are Some People Afraid of Ai If There...?]( URL_5 ) 1. [ELI5: Why Are Some People Afraid of Ai If There...?]( URL_2 ) 1. [ELI5: Why Is Ai a Threat to Humanity...?]( URL_0 ) 1. [ELI5: What Are Real Dangers of Sophisticated Ai...?]( URL_3 ) 1. [ELI5: why Should We Fear Selfaware Robots Why do We...?]( URL_6 )", "There has been a fear of irresponsible science creating a chain reaction that the creator loses control of since Frankenstein, which was pretty close to the point where science began to have a noticeable effect on the common person's life (via industrialization). Since AI is currently a cutting edge research topic, it gets the treatment, too.", "The issue is that there's a lot of complexity to programming a kill switch for AI. Let's just start with a basic off-switch. You have some robot that's programmed to load boxes onto a truck and you have a remote that can switch it off. This is all the AI wants to do. It doesn't want to take over the world or enslave mankind and it never will unless we change what it wants. For now, it just wants to load boxes. Let's say that the robot is loading boxes as normal and it's about to do something wrong and you're getting ready to hit the kill switch. The AI doesn't want you to press that button, because that button will stop it from loading boxes, which is the only thing it wants, so the concern is that it might try to stop you from pressing that button, and that's bad. So let's do some tweaking. Since we can change what the AI wants, we can program it so it doesn't care if the kill switch is hit or not. We can say something like \"if the kill switch is hit, that is equivalent to putting 10 boxes on a truck.\" So now we don't have to worry about the AI trying to stop us, because hitting the kill switch is a good outcome for it. But now we have a different problem: the robot is now incentivized to press the kill switch instead of doing work. So instead of loading boxes, it will just spend all its time trying to get at the button or doing dangerous things so you'll have to press it."], "text_urls": [[], ["https://www.reddit.com/r/explainlikeimfive/comments/2qjz51/eli5_why_is_ai_a_threat_to_humanity/", "https://www.reddit.com/r/explainlikeimfive/comments/38j7zh/eli5_why_are_we_so_scared_of_ai/", "https://www.reddit.com/r/explainlikeimfive/duplicates/4723hy/eli5_why_are_some_people_afraid_of_ai_if_there/", "https://www.reddit.com/r/explainlikeimfive/comments/372l0m/eli5_what_are_real_dangers_of_sophisticated_ai/", "https://www.reddit.com/r/explainlikeimfive/comments/3djisi/eli5why_is_it_considered_dangerous_to_create/", "https://www.reddit.com/r/explainlikeimfive/comments/4723hy/eli5_why_are_some_people_afraid_of_ai_if_there/", "https://www.reddit.com/r/explainlikeimfive/comments/3kn113/eli5why_should_we_fear_selfaware_robots_why_do_we/"], [], []], "score": [12, 7, 3, 3]}}, {"q_id": "6nn10h", "category": "Repost", "title": "How does carbon dioxide trap heat?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkao8ue"], "text": ["Oh this is a brilliantly simple question whose answer is shockingly complicated. It relates to the vibrational modes of CO2 of which only a portion are actively participated in at most temperatures. This portion increases as temperature rises giving CO2 an unusually high specific heat capacity. Interestingly, as a result of this, CO2's heat capacity is dynamic; it can absorb more heat the hotter it gets, which is weird to think about, but it takes a lot of energy before some of its vibrational modes become active, and once they are they can store more heat. I'm finding it very hard to describe this in simple terms because it's a complex problem. But, I'm overcomplicating it in the extreme, and I'm guessing you're not talking about molecular CO2's ability to store energy in the form of vibration, so I'll do a much simpler answer: I'm guessing you're asking because of the Greenhouse Effect. Carbon Dioxide gas traps heat in the atmosphere because it is transparent in the visible and UV spectrum; where most of the sun's light resides. This means it doesn't have much of an effect in reflecting the sun's heat outwards. However, it is partially opaque to the longer wavelength infared light produced when the warmed surface of the earth radiates heat and light. As a result, much of this radiation is converted from infared light and back into heat, which then gradually dissipates throughout the atmosphere and back to the surface."], "text_urls": [[]], "score": [3]}}, {"q_id": "6npqyh", "category": "Repost", "title": "Why do most young children only like very simple foods like plain hamburgers and chicken nuggets, but don't like more complex flavors?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkbae3q"], "text": ["Children's taste buds are more sensitive than adults'. Flavors that are subtle to adults are therefore much stronger to children. As we age, the taste buds become desensitized to the point that we perceive a lot of flavors more subtly. Or so I've heard."], "text_urls": [[]], "score": [6]}}, {"q_id": "6nq7h2", "category": "Repost", "title": "The United States of America's Government.", "title_urls": {"url": []}, "selftext": "I understand that the USA Govt is made up for 3 branches, but the senate and Congress confuses me. It's fairly different from where I'm from. Can someone explain it to me in the most simplest way? Like to 5 y.o?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkbdz8l"], "text": ["There are three pieces to the government: the judicial branch (the court system), the executive branch (the president), and the legislative branch (Congress, i.e. Lawmakers). The legislative branch is made up of two houses: the senate where every state in the United States gets two senators, And the house of representative's where each state gets representatives based on how many people live in that state. This house gets to make up the laws that govern our nation. Once the majority of Congress, as stated in the constitution, passes a Bill it must go to the president to get signed or vetoed (he says it should not be a law). However, even if the president says no then an even bigger majority of the Congress can override that no if they choose. The executive branch is comprised of the president of the United States and his cabinet (advisors). The president runs the country and can pass or veto bills. If he passes a bill it then becomes the law of the United States of America, But if he vetoes it it goes back to Congress and they can still pass it if enough congressman agree it should be law. The judicial branch is made up of the court system. The most important of which is the Supreme Court which has the ultimate authority over the law of the United States. The Supreme Court is made up of nine justices who will rule on cases. It is the judicial branches job to interpret the law the way they see fit regardless of the actual language in the bill. This means overtime the Supreme Court has a large impact in the shape of our future cases (Especially since these nine justices of the court have lifetime sentences). These justices are nominated by the president of the United States when there is an opening and the Congress must approve them."], "text_urls": [[]], "score": [8]}}, {"q_id": "6nrda7", "category": "Repost", "title": "Where did matter/energy come from?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkbnb91"], "text": ["'Twas oft asked here. Ye may enjoy these: 1. [ELI5: if matter can't be created or destroyed, how does matter currently exist? Isn't the existence of matter already breaking that law? ]( URL_0 ) 1. [ELI5: If energy can't be neither created nor destroyed. How did it came into existence? ]( URL_5 ) 1. [ELI5: where did all matter originally come from? ]( URL_6 ) 1. [ELI5: How much energy is in the universe, and where did it come from? ]( URL_1 ) 1. [ELI5: If matter is neither created nor destroyed, how did all the matter in the universe come to be? ]( URL_2 ) 1. [ELI5: Where did all the materials come from during the big bang? ]( URL_4 ) 1. [ELI5: How can the concept of the big bang not violate the conservation of energy & mass principal? ]( URL_3 )"], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/48mzhi/eli5_if_matter_cant_be_created_or_destroyed_how/", "https://www.reddit.com/r/explainlikeimfive/comments/6l5gg2/eli5_how_much_energy_is_in_the_universe_and_where/", "https://www.reddit.com/r/explainlikeimfive/comments/2lfup1/eli5_if_matter_is_neither_created_nor_destroyed/", "https://www.reddit.com/r/explainlikeimfive/comments/3dsb6g/eli5_how_can_the_concept_of_the_big_bang_not/", "https://www.reddit.com/r/explainlikeimfive/comments/1fttxi/eli5_where_did_all_the_materials_come_from_during/", "https://www.reddit.com/r/explainlikeimfive/comments/5t8le2/eli5_if_energy_cant_be_neither_created_nor/", "https://www.reddit.com/r/explainlikeimfive/comments/242qmc/eli5_where_did_all_matter_originally_come_from/"]], "score": [4]}}, {"q_id": "6nt1zr", "category": "Repost", "title": "a PKI infrastructure how does it work", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkc0bkj", "dkcfpe9"], "text": ["It relies on the generation of two \"keys\" that are mathematically related in a way that means that you can only get a \"correct\" result when they're combined. You can't get the correct result if either is wrong or missing. It's not *impossible* to get one from the other, but the mathematics makes it extremely hard to do and depending on the type, requires impossible amounts of computing time. In use, one is \"public\" and is given out, while the other is private and controlled by the user. They are used in different ways depending on the application. If you want to encrypt an email so that only the recipient can read it: * get the recipient's *public* key, and encrypt the email with that; * the recipient gets the encrypted email decrypts it using his or her *private* key, which no-one else has; * so only the recipient was able to decrypt the message; If you want to send a public message that is certified to come from you: * encrypt the message using your *private* key; * other people can decrypt the message using your *public* key; * because only you have your private key, the message *had* to come from you. So it should be clear that managing keys and keeping private keys secure is a big deal, and that's where the \"infrastructure\" comes in, with systems for generating and controlling access to keys. A \"certificate\" as used on the web is an example of the second type of message: it's guaranteed to have come from a particular server or organisation, but only as long as they kept their private keys secure.", "The beauty of PKI is that it solves a couple of big problems: 1. It's easy for two people to have a secret code. But what happens when you want to add a third person? You have to give them the code, and hope that a fourth person doesn't overhear. What happens when you want to add 50 people? What happens when Jimmy accidentally gives the secret code to the wrong person, and now it's not secret anymore? How do you give a new secret code to all 50 people, without anyone catching on? What happens when Marge accidentally gives *that* one away? When do you give up? 2. How do you find out when someone figures out the code? Maybe Antoine was careless. When you get a code from Samantha, are you *sure* it's from her, and not from Merle, the guy down the street that no one wants to be friends with, so you wouldn't give him the code, but he overheard Samantha talking about it with Amy? How do you trust your secret messages are secret? PKI fixes both issues. Everybody has two parts to a secret code, a public key they tell everyone, and a private key they keep to themselves. One of them (either one!) encodes your secret message, and the other one decodes it, **and you can't figure out one from the other** (because, math). If I encode my message with Eric's public key, I can put it out to the whole world and say \"this secret is for Eric,\" and that's safe because Eric's public key can only be decoded by Eric's private key, no one else can read it. And he didn't share it with anyone. And if he did, Eric has a problem, but YOU don't have a problem, because they were Eric's keys, not yours. And Eric can fix the problem by making new keys. You can still send private messages to Cheryl, even if Eric is an idiot. It provides a cool feature, too, that's really useful for legal and banking type stuff. Because the public key and the private key decode each other, and you can't figure out one from the other, you can do it backwards! You can encode a message, and give it to the world, and say \"This message is definitely from me, because my public key will decode it.\" So Merle can't send out a message saying \"This is Carl, I need you all to tell me your codes\" because he has no way to encode it, to make Carl's public key decode it. This is the idea behind digital signatures."], "text_urls": [[], []], "score": [3, 3]}}, {"q_id": "6nu6il", "category": "Repost", "title": "How does a GPU work? What does the data it receives look like, and what tasks does it handle compared to the CPU?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkc7p8y"], "text": ["a really bad way to think of it is comparing it to a CPU CPU's are good for tasks that are like... *we need to go from A to B to C to D in that order*. It'll grind through A- > B- > C- > D with a beefy fast core. GPU's would rather be asked *hey we just need to make sure we hit every letter of the alphabet once*. So a ton of weaker but numerous compute units each go to visit one real fast like POIUYTERQWASDFGFDLJKZCVBXMN DONE!"], "text_urls": [[]], "score": [4]}}, {"q_id": "6nu80h", "category": "Repost", "title": "With no atmosphere to propagate a shock wave, are explosives in space actually even lethal?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkc801v"], "text": ["The gas from the explosive itself will propogate a pressure wave a short distance, but range will be severely limited by the extremely low ambient pressure. At a moderate distance shrapnel would be the greater concern because it won't slow down or stop in space. The shockwave would still cause damage at short range. Depending on the bomb, thermal radiation may also be a concern."], "text_urls": [[]], "score": [4]}}, {"q_id": "6nu8ya", "category": "Repost", "title": "Why are we unable to make gold artificially?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkc7vl2", "dkc7x9j", "dkc7yc9"], "text": ["We *can* produce gold artificially. However, the costs to do so are significantly higher than the gold itself is worth.", "Via nuclear fusion? Because it takes a whole boatload of energy, for a very small output. Much easier to just dig it out of the ground. It can be done - and has been: URL_0 But it's not very practical to make gold a few atoms at a time.", "It is possible to make gold artificially by smashing the right number of protons and neutrons together. The problem is that it requires immense amounts of energy. So much that it is not cost efficient (money wise) to produce gold this way. If there would ever be a gold shortage in the future and the technology improves it's definitely possible that more gold would be made though. The heaviest elements in the periodic table have all been made this way. They don't occur in nature (as far as we know) and are very unstable (they decay in a matter of seconds)."], "text_urls": [[], ["https://en.wikipedia.org/wiki/Synthesis_of_precious_metals#Gold"], []], "score": [6, 5, 5]}}, {"q_id": "6nugfi", "category": "Repost", "title": "What exactly is OCD and Anxiety? (I mean actual OCD, not the \"it's not perfectly symmetrical\" one)", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkcadaz"], "text": ["It's important to note that you can have an anxiety disorder \"with obsessive compulsions\", where it's similar but the obsessiveness is more a symptom of the anxiety than a thing on its own, and I believe anxiety is a part of OCD as well. So there is a bit of cross over"], "text_urls": [[]], "score": [3]}}, {"q_id": "6nujpq", "category": "Repost", "title": "Before Viewing Earth in Space How Were We Able to Get the Exact Shapes of Continents?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkcamih", "dkccrnf"], "text": ["You don't need a bird's eye view to make accurate maps. The very early maps of the coast of the med, africa, indian ocean etc. were not-to-scale and very disproportionate. But once we had the following things, our maps could get pretty good: - accurate time keeping - sextants and sun keeping - accurate compasses - astronomy and how/where the stars were in the sky at various seasons Once you have these things and know how to apply them, you can fix yourself to the surface of the earth to within (guessing) a few minutes of Lattitude / Longitude (which is about a mile). Once you know where you are vs. some reference, and you have a telescope and a compass you can map out the coast that you can see from your ship using trigonometry. e.g.: _We've fixed our position at x long and y lat. from here, the crew in the crows nest have observed there's land at x degrees from our current heading. They know the horizon is ~20 nm away and the land apears to be half that distant._", "'Twas oft asked here. Ye may enjoy these: 1. [ELI5: How was map accuracy maintained before the age of satellites and aircrafts? ]( URL_3 ) 1. [ELI5: How could we have had so accurate world-maps before we could fly/see the world from space? ]( URL_2 ) 1. [ELI5: How were maps so accurate before flight or satellites? ]( URL_0 ) 1. [ELI5: How did early cartographers make accurate maps of the world, before the help of modern technology/satellite imagery? ]( URL_1 )"], "text_urls": [[], ["https://www.reddit.com/r/explainlikeimfive/comments/2vnw8c/eli5_how_were_maps_so_accurate_before_flight_or/", "https://www.reddit.com/r/explainlikeimfive/comments/3cumgz/eli5_how_did_early_cartographers_make_accurate/", "https://www.reddit.com/r/explainlikeimfive/comments/1lnv1i/eli5_how_could_we_have_had_so_accurate_worldmaps/", "https://www.reddit.com/r/explainlikeimfive/comments/2u3s6l/eli5_how_was_map_accuracy_maintained_before_the/"]], "score": [5, 3]}}, {"q_id": "6nupst", "category": "Repost", "title": "Why do people take comfort from crossing their legs or elevating them on a chair/table etc?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkcclyk"], "text": ["'Twas oft asked here. Ye may enjoy these: 1. [ELI5: Why do many have such an irrational urge to sit with a leg crossed (either leg-over-leg or ankle upon knee) as opposed to both feet on the ground, even though it quickly leads to discomfort and the need to then \"switch legs\"...? ]( URL_2 ) 1. [ELI5: Why do we cross our legs? ]( URL_5 ) 1. [ELI5: Why do people take comfort from crossing their legs or elevating them on a chair/table etc? ]( URL_6 ) 1. [ELI5: Why do we feel a need to cross our legs? ]( URL_3 ) 1. [ELI5:Why do we generally cross our legs when relaxing? ]( URL_0 ) 1. [ELI5: Why do we usually cross our legs when we sit? ]( URL_1 ) 1. [ELI5: Why do we cross our legs when we are sitting down? ]( URL_7 ) 1. [ELI5: Why do I always need to cross my legs when I sit in a chair? ]( URL_4 )"], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/4eau41/eli5why_do_we_generally_cross_our_legs_when/", "https://www.reddit.com/r/explainlikeimfive/comments/1xa4pg/eli5_why_do_we_usually_cross_our_legs_when_we_sit/", "https://www.reddit.com/r/explainlikeimfive/comments/1m7p61/eli5_why_do_many_have_such_an_irrational_urge_to/", "https://www.reddit.com/r/explainlikeimfive/comments/4ei1oj/eli5_why_do_we_feel_a_need_to_cross_our_legs/", "https://www.reddit.com/r/explainlikeimfive/comments/28y5r3/eli5_why_do_i_always_need_to_cross_my_legs_when_i/", "https://www.reddit.com/r/explainlikeimfive/comments/2z1pwg/eli5_why_do_we_cross_our_legs/", "https://www.reddit.com/r/explainlikeimfive/comments/6nupst/eli5_why_do_people_take_comfort_from_crossing/", "https://www.reddit.com/r/explainlikeimfive/comments/1pf2ib/eli5_why_do_we_cross_our_legs_when_we_are_sitting/"]], "score": [10]}}, {"q_id": "6nv51c", "category": "Repost", "title": "Why everyone in a \"Pyramid Scheme\" can't make money", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkcfmqm"], "text": ["Pyramid schemes start with a limited set of founders. These people each go out to get 2+ people to pay them for the right to get others to sign up. Those people have to go get 2+ people to pay THEM for the right to get others to sign up. Since there are a finite number of people who can sign up, and the pyramid is exponential for each level of the sign up, eventually you get to the point where there are no more people who you can get to sign up (the entire population of the world can fit in 32 \"tiers\" of a pyramid where each person only signs up 2 others). When the sign up stops, the people on the bottom tier paid money, but don't get paid themselves, and they're the majority of the people in the pyramid (the bottom layer is always the majority, due to the doubling of each layer). Often person-to-person sales (Tupperware, CutCo, Pampered Chef, AmWay etc.) are called pyramid schemes, even though it's possible for the person at the bottom to make a living selling the product -- they just don't get the car, the house, the expensive vacations, etc. These aren't actually pyramids, although the profits made under these schemes definitely follow the same diminishing returns model. Also, when you sell with one of these companies, the first people you sell to are those you know; once you've done that, your market is mostly dried up. The only way to make more money is to sign up other employees who know people you don't know, and take a cut of their sales. This is the \"pyramid\" bit of the schemes."], "text_urls": [[]], "score": [3]}}, {"q_id": "6nvh5v", "category": "Repost", "title": "Why do we get a \"someone's watching me\" feeling when someone is watching us, despite not knowing for sure that we're being watched?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkcizfh", "dkckkfl"], "text": ["We don't really. People get that feeling all the time when no one is actually watching, and they quickly forget it happened. Other times they definitely don't get it when someone is actually watching. But the few times you do get that feeling AND you catch someone looking at you, those moments stick in your memory. So you falsely think you are better at sensing people than you are.", "Our brain picks up on way more things that we are consciously aware of. If our brains didn't filter out information, then we'd be under constant bombardment and unable to do anything. While you may not consciously be aware that someone is watching you, chances are that you may have seen them watching you in your peripheral vision, or heard them approach behind you or something else. Your conscious mind didn't pick it up, but your subconscious has put the pieces together and you get the feeling that someone is watching. Of course, this really only explains the times that you're right about someone watching you. Another commenter mentioned the times that you are wrong that you readily dismiss."], "text_urls": [[], []], "score": [14, 3]}}, {"q_id": "6nvhh4", "category": "Repost", "title": "If most money is just numbers in a database, how come we don't hear of hackers who break in and just increase their account balance?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkcieje"], "text": ["Accounting and balance sheets. Every debit has to have a credit, and every credit a debit...or it will show up as out of balance. If there were to be a balancing entry in the respective offset account, then maybe it would go undetected...but nonetheless it would still show up as an entry that someone is eventually responsible for reconciling."], "text_urls": [[]], "score": [3]}}, {"q_id": "6nvja8", "category": "Repost", "title": "how does a record player produce complex music simply from a grove moving on a vinyl?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkcj6v3"], "text": ["The wiggles in the groove are shaped exactly the same as the sound wave you hear when you play it back. The stylus wiggles back and forth tracing out the groove. The back of the stylus is attached to a magnet which is surrounded by an electromagnetic coil. The movement of the magnet induces electric current into the coil which is sent to the amplifier. Records are able to reproduce stereo sound because the sound wave for the left speaker defines the shape of one groove wall, and the right speaker defines the other wall. Because the two walls are at an exact 90 degree angle to each other, the left-channel and right-channel stylus movements can be sensed independently of each other by two separate electromagnetic coils - one attached to the \"L\" amplifier input and the other to the \"R\". Edit: [Here]( URL_0 ) is a picture of the sound wave from a clarinet playing a single note. The wall of the record's grooves would be shaped in exactly this way if the sound of the clarinet were put on vinyl."], "text_urls": [["https://en.wikipedia.org/wiki/Sound#/media/File:The_Elements_of_Sound_jpg.jpg"]], "score": [4]}}, {"q_id": "6nwwxx", "category": "Repost", "title": "Why are there chess tournaments individually for women and men?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkcufwa"], "text": ["'Twas oft asked here. Ye may enjoy these: 1. [ELI5:Why are men and women segregated in chess competitions? ]( URL_1 ) 1. [ELI5: Why is there a separate league for men and women in chess in the year 2015? ]( URL_5 ) 1. [ELI5: Why do chess championships have a Men's and Women's class? ]( URL_0 ) 1. [ELI5:Why do chess tournaments segregate men and women? ]( URL_4 ) 1. [ELI5: Why are chess tournaments typically separated by gender? ]( URL_2 ) 1. [Why is chess segregated? - Quora ]( URL_3 )"], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/42d6ne/eli5_why_do_chess_championships_have_a_mens_and/", "https://www.reddit.com/r/explainlikeimfive/comments/2ly83y/eli5why_are_men_and_women_segregated_in_chess/", "https://www.reddit.com/r/explainlikeimfive/comments/51o8cl/eli5_why_are_chess_tournaments_typically/", "https://www.quora.com/Why-is-chess-segregated", "https://www.reddit.com/r/explainlikeimfive/comments/2a8fv7/eli5why_do_chess_tournaments_segregate_men_and/", "https://www.reddit.com/r/explainlikeimfive/comments/2v2wq5/eli5_why_is_there_a_separate_league_for_men_and/"]], "score": [10]}}, {"q_id": "6nx2r0", "category": "Repost", "title": "Given the billions of people that have lived and died throughout history, why is it relatively uncommon to find human bones at any given location?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkcw83q"], "text": ["People through out history have usually concentrated into certain areas, ex cities. You probably won't find alot of bones in the Sahara. Also bones can decay and overtime crumble to dust over time. The only reason we find really old bones is because they were preserved: mummies, in bogs (Google bog people), or if really old fossilized."], "text_urls": [[]], "score": [4]}}, {"q_id": "6ny3uk", "category": "Repost", "title": "why do rocking and swaying movements help us fall asleep?", "title_urls": {"url": []}, "selftext": "Thanks for the explanations peeps!", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkd74rc"], "text": ["Rocking and swaying triggers memories of a what it was like for a baby in the womb. It is loud (sounds of flowing blood) and lots of motion from the mother moving around. This is what I remember from reading Dr. Harvey Karp's book _The_Happiesr_Baby_On_The_Block_ - he calls the first three months of an infant's life the \"fourth trimester\" and encourages parents to try to recreate these soothing and familiar conditions to help baby's fall asleep."], "text_urls": [[]], "score": [9]}}, {"q_id": "6o05nk", "category": "Repost", "title": "How does a URL shortener work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkdj9e3"], "text": ["The URL shortener website keeps a simple database which maps the shortened URLs to the actual URLs. When you wish to shorten a URL, the website creates a random string of characters and adds a mapping in the database from the string to the URL you entered. When you enter the short URL, it looks up the short URL in the database, fetches the actual original URL, and sends the browser a redirection to this URL."], "text_urls": [[]], "score": [5]}}, {"q_id": "6o0w02", "category": "Repost", "title": "Where did the idea of a \"dumb blonde\" come from?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkdq9eq", "dkdp2ck"], "text": ["Blondes in society are generally considered to be more attractive as their hair color makes them more desirable. The stereotype is built on the idea that women can get ahead because of their looks and don't need to rely on their intelligence as much. Therefore blondes are \"dumb\" by comparison.", "here's a good thread with an answer: URL_0"], "text_urls": [[], ["https://www.reddit.com/r/explainlikeimfive/comments/389878/eli5_the_origin_behind_stereotype_that_all_blonde/"]], "score": [4, 3]}}, {"q_id": "6o0z90", "category": "Repost", "title": "Why do insects flip over on their back when they die?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkdpgj4"], "text": ["Their limbs are hydraulic in nature and use pressure to move their legs around and to push them out. When they die and subsequently lose control of this system then the legs retract and they tip over - when you see a dead insect flat on their back you also tend to see all their legs curled up in their retracted state."], "text_urls": [[]], "score": [23]}}, {"q_id": "6o1wgv", "category": "Repost", "title": "How does a company monitor my 'Internet usage'", "title_urls": {"url": []}, "selftext": "Ill make this quick. Manager in my work is complaining because I have 'too many Internet Explorers' (tabs) open, saying that when I lock the computer I should close it all down so that no one thinks I'm using the Internet when I'm not at my computer. I tried to argue that most Internet monitoring systems usually check if your going to a new URL as a sign that your on the Internet (something im not 100% sure off). He said that the IT Manager told him that even when locked your Internet tabs ping the IP address and this shows that your own the Internet. I only usual my internet STRICTLY for news and Wikipedia and only ever on my breaks, funny enough unlike my manager who goes on twitter and instagram when he should be working. So how does it work, do companies know when their users are actually on the computer rather than having it locked?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dke396f", "dkdxpyw"], "text": ["> So how does it work, do companies know when their users are actually on the computer rather than having it locked? There are a variety of ways you can be monitored. First we should go over the basic setup of a typical network: Your computer is connected to a local router along with all the other computers in your home or office. This local router forms a \"LAN\" or local area network. If you connect via wifi or plugging a network cable in it works basically the same. From that router it connects to your ISP and on to the internet at large. Everything going in or out of your computers is going through this router and is subject to inspection (provided it isn't encrypted). The most common method is through \"filtering\" where if you say \"Show me this porn website\" the router will check the address against a big naughty list and if it is present will refuse to forward the request on, instead displaying a generic blocked message. It can also make a record of the blocked request, or record all requested sites regardless of legitimacy, or whatever it is set up to do. This system is purely automated and is not being monitored by a real person unless something very unusual occurs; in fact the compilation of the \"naughty list\" of sites is almost always farmed out to a third party service so whoever is keeping the records probably isn't in your company! Another way of monitoring is to have software directly installed on your computer to allow \"remote access\". This is where the \"seeing your desktop as you do\" comes in and it is certainly possible. However again nobody really has the time to bother with this 99% of the time. Now for your internet habits. Browsers on web pages can actually generate traffic just sitting there if for example they are set up to refresh new ads or reload to check for breaking news. I can definitely see this happening on news websites so it may be that a bunch of tabs can generate a ton of small requests but they wouldn't equate to network congestion. When your computer is locked the requests should stop as the browser is suspended, but when you log back in there will be a flurry of network requests. The bigger question is \"Why does it matter?\" If you are doing a good job then why would your internet history even come up? If they can't tell if you are doing a good job without checking your network logs then they have a major performance assessment problem, not a need to change your browser tab habits. It sounds like either the IT manager is getting too nosy or your manager doesn't really understand what the IT manager was saying. It might help of you rephrased what the IT manager said: Network traffic and URL requests are poor indicators of if someone is actually on the computer. Tabs left alone can generate traffic visible to IT so asking IT about computer usage by employees isn't a question they can reliably answer. Your manager will need to manage their own employees because IT isn't going to allow that responsibility to become their problem.", "They have 100% remote access to your computer. There is a person sitting in a room who can see everything that you see and everything you type on their computer WHENEVER they want. It's not practical to access everyone's computer all the time, but they can and they do. If your manager said something, that means you were flagged for something. I'll explain my experience below. They can also see collectively for the whole company who is using what type of websites and services online. They can see if you are on a website that has a lot of ads and it can be perceived that you are shopping at work even if you aren't shopping at all. I am not a technical person, so, I can't explain this in technical words, but the day that I learned the IT person had 100% access to watch what I was reading all day at work opened my eyes. I was never doing anything wrong, it was just embarrassing to have someone tracking every article I read. They CAN record what you are looking at and can keep it. I had trust in my IT guy's ethics and we spoke often, so, he tried to make it explicitly clear that he had 100% access to everything I did so I would not do anything weird ( he knew I was weird and liked to research controversial topics ). One day Vice magazine was flagged on my computer and I called him and told him \"wtf, I need to research this issue\" and it was legit- Vice magazine also called to interview my boss, but he told me that Vice magazine's 'not safe for work' tab was flagged as pornography. In context, it's FINE. Out of context, that stuff can look really sketchy on paper and they can fire you down the line for something like that. I keep a hand-written diary or a word document at my desk to jot down what I do each day. \"May 1st, 2014, Researched congressional action on BLAH BLAH and its effect on transgender community\"- that way if anything gets flagged as porn, I can show someone two years later what my line of thinking was for hitting a transgender porn website accidentally. Something like that would probably help you stay out of trouble. And if he said to close the tabs, just close the tabs and 're-open' your closed tabs when you get back from lunch. They can see what is on your computer whether it's locked or not is my guess."], "text_urls": [[], []], "score": [6, 3]}}, {"q_id": "6o4q7p", "category": "Repost", "title": "Random number generators work off seeds but how is the seed itself randomly generated?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkemfyh", "dkekxel", "dkekvmd", "dkemekr", "dkekw2v", "dkekyt0"], "text": ["There are only 3 sources of truly random data: nature, humans, and time. Most modern computers are using processors that have a native entropy collection instruction, for example Intel chips can gather a word of random data from thermal fluctuations in the silicon chip. Human input also turns out to be very random, the mouse wiggle to get entropy is surprisingly good. The last source is the amount of time it takes to do something. A common method is to create a race between threads such that the ordering of execution is nondeterministic. These are all ways to seed a cryptographically secure random number generator. EDIT: It seems many of you take issue with the words \"truly random\", a sentiment I can appreciate, so let me be a bit more specific. I mean truly random in terms of computational complexity. There very well might be sources that are \"more random\" getting into quantum effects, however if the data produced from these sources are computationally indistinguishable from traditional sources then why does it matter? In terms of a sequence of independently distributed bits, they are equally random by all computational means we currently have. So I guess I'll say a source of truly computationally random data instead then to be precise.", "Generally the seed is the number of milliseconds since \"zero\" in whatever system is being used to measure time. Jan 1st 1970 is a common start point for systems. This means that each time you run it the seed will be different, so it's close enough to random. If you want to ensure it differs even if is seeded on different computers at the same time you can take the time and combine it with something unique to the computer, like a MAC Address, but usually the time does the job. This is also why sometimes new programmers run into a trap where they seed a RNG then generate a number, than seed it, then generate over and over again. If you do that you'll get the same number. Because the same seed is used because the time hasn't had a chance to change yet. The right way to do this is seed once, then generate many numbers.", "If you don't want to explicitly seed the RNG to produce predictable results, you normally set it with a timestamp.", "As others have said, it's usually something that changes regularly and is difficult to guess. Current time to the millisecond is a common one. However, there are many others, and I have a funny story about one to give you an example. Remember Mario Kart DS? I got into a routine where whenever I was going to poop, I'd bring my DS with me and play a one-player four-race series with random tracks. Every single time I'd do it, I'd follow the same sequence of operations: open the DS, open the game, select the right options, select the same character, start. I quickly discovered something: the game was using some component of that as its random seed. It might have been current total number of button presses, for example. I discovered this because *every* single time, the game chose the same four tracks, in the same order. If you have Mario Kart DS and a DS handy, try it. Turn on the game and play a four-course randomly-picked sequence. Close the game, reopen it, and do the exact same sequence of operations: it'll choose the same courses. I don't know if they're the same for everyone or if everyone gets their own set, but it should be the same for your game time and time again.", "It's not *truly* random, it's just very hard to guess. Typically the seed generator will start with the time of day in nanoseconds, and then combine other unpredictable garbage like the status of the nearest disk drive. For hardcore randomness: I've seen one program that asks the user to wiggle the mouse randomly, and another one that looks at the \"noise\" (random electrical signals) coming from a webcam in the dark.", "Depends how random you need your random number to be. If you really want it to be random, you base it off of something like the thermal noise in the computer. If you don't need it to be quite so random, you can use something like the current time in microseconds at the start of the program."], "text_urls": [[], [], [], [], [], []], "score": [53, 52, 41, 13, 11, 10]}}, {"q_id": "6o7gpt", "category": "Repost", "title": "In movies and TV shows, people that have amnesia lose their memories but not their language and skills. Is this really the case?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkf6qv0"], "text": ["The brain has several specialized systems for different jobs, and they can indeed fail independently of one another. This means losing things like semantic memory (facts about the world), muscle memory (physical skills) and episodic memory (events of your life) can happen independent of one another. Actual amnesiacs can present in many ways, but story writers usually prefer the kind who get a mystery to drive their character arc but doesn't take away the skills they need to drive the plot forward."], "text_urls": [[]], "score": [5]}}, {"q_id": "6o7wz4", "category": "Repost", "title": "How did doctors find out which parts of the brain control different things (like individual emotions, pain, happiness, all 5 senses, etc etc)", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkfab1g"], "text": ["Most of the original discoveries were made by observing and documenting patients who had a brain injury which disabled or damaged a certain part of the brain and working out by the deficits in their perception or action, what that part was responsible for (for example google \"Phineas Gage\" if you haven't already heard the story, his frontal lobe was damaged by an iron rod and that left him the problems with his personality). Now tools such as fMRI (functional magnetic resonance imaging) can show which regions of the brain light up in certain circumstances and give a good idea of what does what, although science is still tenuous about ascribing regions to control of the different regions for definite."], "text_urls": [[]], "score": [3]}}, {"q_id": "6o9c0k", "category": "Repost", "title": "How is car GPS usage free?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkfk9rr", "dkfklg6", "dkfm7b1", "dkfkled"], "text": ["Your GPS isn't eating bandwidth or communicating with some satellite. It's entirely reception. Satellites are sending out a signal. Your device is receiving them from multiple satellites, and calculates its position based on what it receives.", "Think of standing in a field, with three mountains off in the distance. On top of each one of those mountains is a guy with an extremely bright flashlight, in fact, three flashlights, one red, one green, and one white. Every second the people on the top of those mountains flash one of those flashlights, first they all flash the red one, then a second later they all flash the green one, then they all flash the white one, then repeat. If you had a sensitive enough stopwatch, you could record the difference in time of each flash and figure out how long it took to get to you and use triangulation to figure out how far away you were from each one and therefore determine your exact location. That's all that is happening with GPS. The satellites are transmitting a satellite number and a time code, over and over and over, multiple times every second. Your GPS receiver knows what time it is, and can determine how long each of those time codes it's picking up differ from it's internal clock. So once it picks up three or four time codes from three or four satellites, it can then do the math to find out where you are, as it knows how fast radio waves travel. The satellites themselves were set up to just autobroadcast their information forever. They were set up for the military to use, so that's who is paying the bills to keep them up in the air, and to replace them when they wear out. Private companies figured out how to read the time code data that was being transmitted endlessly, and from there it was easy to build a device to do the rest.", "GPS signals are broadcast like radio. It is only a one-way transmission, so one set of satellites can cover the entire planet. Those satellites are government owned and paid for with tax dollars. Also, the government launched them for its own purposes, we kind of get to use them as a side benefit.", "GPS was originally for military use only. If a civilian was using GPS in the 90s their location was not pin-point exact because of some intentional selective availability. Clinton made a directive around 2000 that removed the selective availability and civilian use became very reliable. The maps like TomTom and Garmin and such are privately made so you may need to pay for updates or subscriptions. But the satellite signal is free courtesy of the US government and your taxes."], "text_urls": [[], [], [], []], "score": [10, 6, 4, 3]}}, {"q_id": "6oa32s", "category": "Repost", "title": "Why do we tend to only get thunderstorms in the evening or night, why are they rare during daytime?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkfqppv", "dkfxwxi"], "text": ["They happen most when there is a temperature gradient. During the day, the temperature is hot everywhere and night, the air higher up cool rapidly. The air lower down is still very hot. this leads to clouds forming up high and having a large electrostatic potential", "There are two types of thunderstorms: - Cold front thunderstorm, this one can happen any time when cold front is passing over area. - Cumulonimbus \"thundercloud\" thunderstorm, this one happens in evening because those clouds need time to grow. They form from hot air currents at morning, then form small cumulus clouds around noon, and if conditions are right, they to grow couple miles upward forming cumulonimbus."], "text_urls": [[], []], "score": [13, 4]}}, {"q_id": "6oaccx", "category": "Repost", "title": "How come when you close your eyes and press against them, you begin to see colorful light that continues to get brighter while you maintain pressure?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkftcha"], "text": ["While photons can stimulate the cells in your retina, they aren't alone. Electrical stimulation, and pressure, can also both provoke them to signal, among other sources. Those signals are sent to your brain. As far as your brain is concerned, it simply sees that a signal is coming to it along the optic nerve, and so it attempts to make an image. These are called [phosphenes]( URL_0 ) if you wish to read further."], "text_urls": [["https://en.wikipedia.org/wiki/Phosphene"]], "score": [7]}}, {"q_id": "6ob5pe", "category": "Repost", "title": "How can forest fire can be a good thing for the environment?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkfzypi"], "text": ["This has been asked before, here is a good answer: [ URL_0 ]( URL_0 )"], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/4qv2sf/eli5_why_are_forest_fires_considered_good_for_the/d4wa9uc/"]], "score": [6]}}, {"q_id": "6ob84e", "category": "Repost", "title": "does blood actually pour out of your mouth if you're stabbed or shot? If so, why?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkg0jmi"], "text": ["Blood welling out of the mouth can either be coming from the stomach or digestive tract, in which case it is called haematemesis (vomiting blood), or from the lungs and respiratory tract, when it is termed haemoptysis (coughing blood). Another alternative is that the bleeding is from a structure inside the mouth, such as the tongue. So generally speaking, trauma to the abdomen may cause haemtaemesis, while trauma to the chest would be more likely to cause haemoptysis. Its pretty unusual for an abdominal wound to cause a large amount of haematemesis, as an injury that damages a blood vessel inside the abdomen will cause the bleeding into the abdominal cavity, but not into the digestive tract itself. So, one might see a distended, tense abdomen, and a low blood pressure, but unless there was also a hole in the stomach or intestine, there may well be no bleeding from the mouth. In contrast, damage to the lungs is much more likely to cause haemoptysis, as the lungs are full of blood vessels, and its very easy for blood to leak into the airways, and so be coughed up. A wound to one of the major pulmonary blood vessels can lead to massive, torrential bleeding from the mouth and can be very difficult to treat. Edit: words."], "text_urls": [[]], "score": [11]}}, {"q_id": "6oc0h0", "category": "Repost", "title": "Why does it take so much time and encouragement for humans to learn how to walk but other animals can almost instinctively walk/fly sometimes within minutes of being born?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkg7h0z"], "text": ["Humans have a relatively big brain-to-body-weight ratio, especially for a good-sized land-dwelling animal. We also have a pelvis that evolved for a four-legged creature and had to be adapted for our current bi-pedal form. This means that it's a little tricky to get our babies' big ol' heads through their mother's lady parts. To make it a little easier human beings come out a bit undercooked, before we've fully developed and have really good control over our bodies. That lets us be born with smaller craniums so fewer mothers die in childbirth. We're also smart social animals that can handle caring for useless babies, unlike, say, gazelles, who might have to be running from predators within minutes after birth."], "text_urls": [[]], "score": [3]}}, {"q_id": "6ochdc", "category": "Repost", "title": "When you die from cancer (brain, bone, liver, etc.), what happens to you physically that eventually causes your body to shut down and die?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkgdl78", "dkgbkpz"], "text": ["I can speak about a specific type of cancer and how it causes death: AML, or [acute myeloid leukemia.]( URL_0 ) This is a personal story, because I was diagnosed with such a cancer in 2010 and during my treatments, I learned a lot. So, Mods, if this is against the rules, I am fine with that. So, your bones contain marrow. The marrow tissue is what makes all of your blood cells, red, white, platelets, plasma, etc. Each of these cells grows from stem cells into the mature cells, kinda like how a baby is grown in a womb. Well, at some point in the growing stage, a white cell stops growing properly. These cells end up staying in the bone marrow since they aren't ready to be born. The body is still getting signals to make these cells, as the cell count in the bloodstream for the mature cells is down. Eventually, these immature cells get pushed out of the marrow and into the blood stream. While this is happening, few if any of the other cells are being made, in particular platelets. What are platelets? Those are the blood cells that stop bleeding, and are some of the most numerous cells in your blood. If you blood vessels get a tear, these cells will get caught, break open and start a protein scaffold to hold the other blood cells in preventing you from bleeding out. Bleeding out is bad. Unbeknownst to you, you are constantly bleeding, but the platelets stop that bleeding. Sooner, rather than later, the platelets in your blood stream run out and need to be replaced. But your bone marrow cannot make more of the platelets because the blast cells (those immature cells I was talking about earlier) has taken up all the room. What side effects occurs? Well, since you can't stop bleeding, you'll start getting these little brown dots on your extremities. Those are micro bruises. You become short on breathe because of the lack of red cells. When you do get cut, it'll bleed for a long time and the blood will be extra thick since these blast cells are heavier than other cells. When you brush your teeth, your gums will bleed and won't stop. With AML, you'll bleed out in one form or another. Either internal bleeding, from a cut that's bad enough to keep going, or, the worse that I imagined for myself, getting a nose bleed while sleeping and in-essence drowning in your own blood. You will also be more susceptible to infections as your immune system is not right. I will be happy to share more information not related to death via cancer (cause you know, it's kind of a downer topic), and of the treatments so don't hesitate to ask.", "In general, the cancerous cells starve out functional cells until they die. This eventually leads to organ failure and thus death. For cancer that forms in non-essential areas of the body, the cancerous cells eventually break off into the blood stream and begin reproducing in more vital areas of the body, ultimately starving them and causing organ failure and death."], "text_urls": [["https://en.wikipedia.org/wiki/Acute_myeloid_leukemia"], []], "score": [7, 5]}}, {"q_id": "6ocp7o", "category": "Repost", "title": "How can scientists know if there is a earth-like planet light years away from the earth if they can't prove the planet 9 in solar system?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkgd60j"], "text": ["they can look at the \"wobble\" of the light shift coming from distant stars (red-blue-red-repeat light shifting) which is caused by the planets gravitational pull on its star and its revolution around the star. the magnitude of this wobble effect will be proportional to the planets mass and distance from the star. in order to be \"habitable\" it must be at a certain distance from the star (so temperatures are not too high or low) and also of certain mass (for adequate atmosphere/gravity/etc)"], "text_urls": [[]], "score": [3]}}, {"q_id": "6oczjh", "category": "Repost", "title": "Why does beer foam when you pour it directly into a glass from a pitcher/fraught/can but when you pour it into a tilted glass there is little to no foam", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkgfkqe", "dkgfi0s"], "text": ["Adding to /u/kg989 Also because having the Liquid run along the side of the glass, only 1-2 millimetres high until it hits the \"pool\" at the bottom, gives the gas much more surface area to escape into the air. And the flow of the liquid destroys the foam as it flows down When you pour it into the pool directly the gas gets shaken up into the drink more, takes a part of the liquid and carries it to the surface of the pool, where the surface tension of that very liquid creates bubbles around the gas - the foam.", "Think of it like soda. Soda does the same thing when you pour it straight into a glass. While soda is a lot fizzier than beer usually is Beer still has a good deal of bubbles too. When you pour the beer directly into the glass and it hits the flat surface head on it churns the beer which releases a lot of the gas dissolved in the liquid. This keeps happening as more beer is poured into the glass and churns the rest of the beer already in there releasing more bubbles that then rise to the top and gather creating the foam. If you look under the foam while it's being poured you can see smaller bubbles being created and rising as you pour. Now when you gently pour the beer against a tilted glass it slowly flows into the bottom of the glass without churning as much. This in turn does not release as much of the gas from the beer and so not as many bubbles are created. When you gently pour the beer down a soft incline the beer flows slowly and gently and fills the glass without a lot of foam being created. source: Have poured many, many beers."], "text_urls": [[], []], "score": [5, 4]}}, {"q_id": "6odfxr", "category": "Repost", "title": "How does an object \"gain mass\" the closer it gets to the speed of light?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkgjqb6"], "text": ["Typically the object is actually gaining energy as it gets faster. Usually this energy comes from fuel or from falling into a gravity well. The kinetic energy of an object in classical mechanics increases proportional to the velocity squared. Your energy doubles, you go 4 times as fast. As the energy of your object increases however, it's mass will increase accordingly (given by the equation E=mc^2 ). There's no real \"how\" to this in a traditional sense. There isn't a mechanism I can reduce to smaller pieces and explain, or even a process I can break down. I can tell you that it happens in a bunch of different ways, but since we know that mass and energy are equivalent, one can simply transmute into the other. This happens at all energies, as well. When you're walking you weigh slightly more than when still, because you have more kinetic energy when walking, and E=mc^2 . This is why the masses of fundamental particles are listed as their \"rest masses\", ie, the masses of those particles measured by something stationary relative to them."], "text_urls": [[]], "score": [5]}}, {"q_id": "6oe4ju", "category": "Repost", "title": "What is the difference (at least in the southern US) between sheriff cars, constable cars, state troopers, and regular police cruisers?", "title_urls": {"url": []}, "selftext": "Mainly relating to jurisdiction and duties, like working traffic stops, directing traffic, homicide, etc.", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkgrdp5", "dkgqv7s", "dkgqxf9"], "text": ["'Twas *very* oft asked here. Ye may enjoy these: 1. [ELI5: Differences between or roles/duties of police, sheriff, state police, US Marshalls, highway patrols etc. ]( URL_1 ) 1. [ELI5: The difference between Police, Sheriff, Constable, and State Trooper. ]( URL_7 ) 1. [ELI5: What's the difference between Police, State Troopers, and Sheriffs? ]( URL_5 ) 1. [ELI5: what's the difference between city police, state troopers, highway patrol, and sheriffs? ]( URL_4 ) 1. [ELI5: What does a sheriff do? And how is it different from normal police? ]( URL_6 ) 1. [ELI5: FBI vs State Trooper vs Police vs Sheriff etc in the US. What's the difference? ]( URL_2 ) 1. [ELI5: In the United States, how do Sheriff and Police jurisdictions overlap? If a Sheriff needs backup and he's within city limits, will that city's police department help? Do they share a radio frequency? How do they cooperate? ]( URL_0 ) 1. [ELI5: Sheriff's Department Vs Police Department ]( URL_3 )", "Police: Have jurisdiction in a city or town. Their authority stops at the city limits. Sheriff: Have jurisdiction in an entire county. They technically supercede the jurisdiction of the city police, but seldom ever overrule them. They tend to patrol outside of city limits, but will help when needed. They will also deal with crimes that cross into multiple cities or is city and rural within a county. Constables: There is no real standard use of the title in the US. In most places though they are not full police officers, but are instead officers of the court. They could be in charge of: Giving subpoenas for court summons, provide security for the courts (primarily through bailiffs), and may be in charge of guards in prisons or jails. But in some States they function virtually the same as a Sheriff with all the same authority. State Troopers/State Police: These have jurisdiction in an entire state. For the most part they will patrol highways but they can assist or supercede any jurisdiction within the State. They will deal with crimes that cross multiple county jurisdictions. As for the vehicle differences. That is dependent on the choices of the specific department.", "It varies wildly from state to state. I will talk about my home state of Tennessee here. Other maybe someone from another state will add to this. In Tennessee each county has at least a sheriff. Sheriffs for the most part operate outside of city limits enforcing laws and investigating crimes in none incorporated areas of each county. Sheriff is an elected position and answers to no one but the citizens. Sheriffs are usually in charge of running the Jail or other other prisoner incarceration facilities within each county. Sheriffs my also act within cities with no police force. Police operate inside city limits investigating crimes enforcing laws within the city. Police chiefs are normally appointed by and answer to the city counsel, who in turn are elected by the citizens. In some areas police chiefs are elected positions. State Troopers in Tennessee are normally only concerned with enforcing traffic laws and investigating accidents. State Troopers may also enforce other laws such as drug trafficking, but this is usually in connection with traffic enforcement. State troopers are usually found only on state and federal roads and are rarely encountered on county and local roads. Traffic accidents are normally investigated by police within city limits. Sheriffs will normally investigate accidents on county and local roads outside city limits, and State Troopers normally investigate accidents on State and Federal roads. However there is some overlap and State Troopers may, in the absence or on request of, other authorities investigate accidents anywhere on any road in the state. Constable is usually a volunteer position often filled by older retired law enforcement officers. A Constable is a county position in Tennessee, and are usually only found in low population counties with low law enforcement funds. Constables are tasked with ensuring public safety in a general sense. Constables act as the the most basic law enforcement authority in the absence of other agencies, but their authority can be very broad, Constables may enforce traffic laws, public duskiness laws, and even investigate minor property crimes. Constables act as a visible law enforcement presence in the absence of other agencies. Constables in some counties may be a paid position, but this is rare. In Tennessee most counties have abolished the position of Constable as the sheriff's department handles basically the same task. There are only a hand full of Tennessee counties that still have Constables. Tennessee also has another law enforcement division known as the TBI (Tennessee Bureau of Investigation). The TBI is often called in for major crimes in smaller counties, such as murder or organized crime. But the TBI has another MAJOR part to play in Tennessee law enforcement. The TBI investigates wrong doing by other law enforcement agencies. For example last year there was a sheriff that was using his position as sheriff to direct all contracts and purchases made by the county jail to his companies or companies run by family members. The TBI marched right in to the Sheriff's office, which by the way was in the same building as the jail, and arrested the Sheriff and walked him right out of his own office in handcuffs. Maybe someone can add more about other states."], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/6gt8t0/eli5_in_the_united_states_how_do_sheriff_and/", "https://www.reddit.com/r/explainlikeimfive/comments/3b0ahq/eli5_differences_between_or_rolesduties_of_police/", "https://www.reddit.com/r/explainlikeimfive/comments/2oe97i/eli5_fbi_vs_state_trooper_vs_police_vs_sheriff/", "https://www.reddit.com/r/explainlikeimfive/comments/35htd3/eli5_sheriffs_department_vs_police_department/", "https://www.reddit.com/r/explainlikeimfive/comments/3sb4jb/eli5_whats_the_difference_between_city_police/", "https://www.reddit.com/r/explainlikeimfive/comments/1n7olp/eli5_whats_the_difference_between_police_state/", "https://www.reddit.com/r/explainlikeimfive/comments/1nq6iw/eli5_what_does_a_sheriff_do_and_how_is_it/", "https://www.reddit.com/r/explainlikeimfive/comments/1bjkcv/eli5_the_difference_between_police_sheriff/"], [], []], "score": [6, 3, 3]}}, {"q_id": "6oeeh1", "category": "Repost", "title": "Why is is that many people are pushing to get mankind to colonize other planets, when are own uninhabited oceans are such a huge percentage of our own planet and so accessible", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkgr5sz", "dkgryfn", "dkgr8cg", "dkgrifj"], "text": ["Among other things, establishing human colonies in the ocean does little in terms of an insurance possibility for human existence beyond the planet earth. Plus, as someone may have told you, don't shit where you eat. Other colonized planets, at the point they become self-sustaining and outward-growth capable, are a quantum leap forward in that respect. That's a long step forward from some colonization but it's a step that has to be taken first to begin the journey. Then outside the solar system, the galaxy, etc. Natural instinct to survive will get us out there eventually, if soon enough.", "Say you're running a datacenter. Your servers aren't empty, but they aren't full either, they still have decent amounts of room. Your client however, considers their data to be extrodinarily important, they will sue you personally into oblivion if it's ever lost. Space isn't the issue, you got a spare closet, you could fill it with more server racks if needed. However your data center is located in an earth quake zone. If a big quake hits and your data center is leveled, you lose your data, doesn't matter if it's in the data center main floor or in the closet. So you build a backup data center in the next town. Ideally you want them on several towns, if possible some of the town in another country. The more towns it's in, the further apart, the less likely you'll lose your data to a disaster. Likewise with colonies, if an asteroid hits Earth, those sea colonies will be just as dead as our cities. If a gamma ray burst hits the solar system, that Mars colony is going to be just as dead. If we had colonies on Mars and on another solar system, there's pretty much nothing that we know of that can cause the extinction of the human species.", "If we want to survive(progress) as a species we have to move on. We are quickly reaching the point of no return and making this planet unsuited for such a large polulation. But realy, making permanant settlements on other planets and moons in the solar system is just the first step, and colonizing the galaxy will be the next logical step.", "'Twas oft asked here. Ye may enjoy these: 1. [Will we ever colonize our solar system? ]( URL_3 ) 1. [ELI5: Why are we trying to colonize Mars? ]( URL_5 ) 1. [ELI5: Why colonize Mars? Wouldn't it be more efficient to fix things on planet Earth? ]( URL_2 ) 1. [ELI5: Why are there people talking about colonizing Mars when we haven't even built a single structure on the moon? ]( URL_1 ) 1. [Why bother colonizing planets? ]( URL_0 ) 1. [ELI5: Why is there such a big push to colonize Mars when it doesn't appear necessarily more viable than colonizing the deserts of earth? ]( URL_6 ) 1. [Space Colonization ]( URL_4 )"], "text_urls": [[], [], [], ["https://www.reddit.com/r/space/comments/4khzme/why_bother_colonizing_planets/", "https://www.reddit.com/r/explainlikeimfive/comments/2wznzv/eli5_why_are_there_people_talking_about/", "https://www.reddit.com/r/explainlikeimfive/comments/3lczcu/eli5_why_colonize_mars_wouldnt_it_be_more/", "https://www.reddit.com/r/space/comments/3twz1m/will_we_ever_colonize_our_solar_system/", "https://www.reddit.com/r/Space_Colonization/", "https://www.reddit.com/r/explainlikeimfive/comments/56yhqp/eli5_why_are_we_trying_to_colonize_mars/", "https://www.reddit.com/r/explainlikeimfive/comments/2qqz7o/eli5_why_is_there_such_a_big_push_to_colonize/"]], "score": [12, 4, 3, 3]}}, {"q_id": "6of8rt", "category": "Repost", "title": "What's the difference between name brand and generic branded drugs?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkgwgo1"], "text": ["Most of the time there's no significant diffrence except the price of the drug. When a pharma company develops a new drug they're allowed to keep the patent on the drug for an x amount of years, for that time they've effectively got a monopoly on the production and sale of the drug. This is in order to recoup the development costs of the drug. After several years this patent expires and everyone is allowed to produce the drug, leading to the much cheaper generic brand versions of the drug."], "text_urls": [[]], "score": [6]}}, {"q_id": "6ofccg", "category": "Repost", "title": "How does gas rise if the gravity of the earth pulls everything towards its center?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkgyk02"], "text": ["It is not so much that the gas rises despite gravity but because of it. Gravity pulls down a kilogram of lead exactly as much as it pulls a kilogram of hydrogen gas. If you had a ballon filled with helium or hydrogen and let in go in chamber with no air in it it would drop like a lead weight. (Okay it would explode in practice most likely but if you made the ballon from material that would not just burst apart it would drop like a stone.) The problem is that a kilogram of practically everything up a much smaller volume than a kilogram of hydrogen gas. Hydrogen and helium are much less dense than normal air (which is a mixture of several gasses including hydrogen and helium). The pull of gravity is stronger on heavy gasses than on lighter gasses of the same volume. Everything gets pulled down towards the center of the earth, but usually there is already something there. If something gets pulled down it will have to displace something else already there and push it aside and higher up. Something that is denser than what is there can displace the substance beneath it and sink. Something that is lighter will not be able to dow that. The air gets pulled down stronger than your helium ballon and makes it rise up. You have the same effect with fluids of different density that don't mix with each other. Oil will float on water. Ships despite being certainly quite heavy float in water because they are lighter than the water they displace. If you sit in your bath-tub you experience a certain sense of being much lighter, not because gravity doesn't affect you as much, but because it affects the water around much stronger than it dos the air you are normally in. It may help to think of it as gravity ending up sorting stuff in layers with heavy stuff at the bottom and light stuff at the top. lighter stuff rises and heavier stuff sinks to the correct place in that order (in practice it is much more complicated than that). It means that some gasses which are heavier than normal air will pool at your feet if released and other which are lighter will rise to the ceiling. Warm air rises against cold air because it is lighter."], "text_urls": [[]], "score": [7]}}, {"q_id": "6ofe1d", "category": "Repost", "title": "The relationship between water and fire", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkgyyza", "dkgxf8k"], "text": ["I think you're misunderstanding what fire is. I guess you can think of it like a chemical reaction that is self sustaining; the energy output is greater than the input required. It's not a \"thing\" like water, it's an action a \"thing\" goes through. It's not so much \"removing one of the three thing that make up fire\" so much as slowing the reaction itself to the point that it isn't self-sustaining. To your further question of \"at what point does fire ______\u201c, well, depends how self sustaining the material is once it reaches its unique \"flash point\".", "You need 3 things to make fire: heat, fuel and oxygen. If you take away one of those things, there is no fire. Water works by taking away heat and to an extent oxygen via smothering. There is no ratio to my knowledge of how much water you precisely need to extinguish a fire - it's just one of those things that you keep adding until the fire is out."], "text_urls": [[], []], "score": [5, 3]}}, {"q_id": "6ofrt5", "category": "Repost", "title": "What happens to the newly \"dead\" bacteria on your hands after you use hand sanitizer that \"kills\" bacteria?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkh5klv", "dkhuyxt", "dkh6nvj", "dkh716u", "dkhi1c5", "dkh7lzb", "dkh95mg", "dkhkntj", "dkh90rx", "dkh3gr0", "dkht7op"], "text": ["Like another poster has said, you can't really wash off the dead bacteria because water acts differently on them due to their size. Also when you use antibacterials, the area will quickly become repopulated with bacteria from your environment, other parts of your skin and by the bacteria that wasn't killed multiplying. As the area becomes repopulated, the new bacteria will use the dead bacteria as a food source. In essence, the dead bacteria becomes food for the still living bacteria. Edit: words - silly phone predictive text.", "So i had to remove the top reply in this thread. I know people are going to want to know why, and my explanation is buried there. It was a copy and paste of [this comment by /u/TheTimeNotTheMiles]( URL_0 ). That is one of the reasons that the OP of the removed comment didn't respond to anyone. That violates our [rule #3]( URL_1 ) explicitly. I think though that it violates the spirit of rule #1 as well. --- I'll post the contents of that original comment here for convenience. > So lets say we have a scalpel, right? Simplest medical device there is. There's a number of ways to make it totally(ish) sterile- gases, steam, dry heat, gamma radiation. > But as you ask- the little bacterial corpses are still there. Waiting, one presumes, for tiny necromancers. > The problem occurs when you stab someone with the scalpel, preferably in a medicinal way. The bodies immune system works by identifying certain chemical triggers in bacteria, and has no way to know that, for example, the lipopolysaccharide hanging around in someone's heart is not part of a bunch of living bacteria, but the floating corpses of dead bacteria. > The dead byproducts of bacteria are called \"pyrogens\" because they cause (among other things, such as death) fevers. > Where do they go? Nowhere. Bacteria are small enough that water has completely different properties on their level. Beyond rinsing off gross matter and reducing bacterial load, washing can't do much. > So for things like heart surgery scalpels, there will usually be a second step of \"Depyrogenation\" This is the process, not of killing bacteria, but of removing the bits left behind so they don't trigger an immune reaction. This varies widely in complexity depending on what you have to depyrogenate- steel scalpels are easier than an injectable drug, for example. Typically, the goal of the process is to so thoroughly break down the biological material left behind. > **Are my hands covered in bits of dead bacteria?** > No your hands aren't covered in dead bits of bacteria. They're covered in happy, healthy bacteria. > **Then why wash my hands??** > Washing your hands removes dirt and debris that carry the nastiest bacteria. Sterilizing your hands is a ridiculous notion however- your hands are made of cells, bacteria are made of cells. Anything that would kill them would kill your cells. Your hands, and literally everything else on the world not currently under direct gamma radiation bombardment, are covered in bacteria, > Quick run down on terms: > \"Cleaning\" a medical device is basically doing dishes-getting blood n bits off the reusable ones. (plz dont reuse single use medical devices that makes regulatory professionals sad \ud83d\ude2d) > \"Disinfecting\" is using chemicals to get something purty darn clean. > \"Sterilization\" is killing all* the germs on something > \"Depyrogenate\" is taking bacterial corpses and reducing their remaining structure to a point where your immune system won't recognize it and freak out. > *SALx10-6 is the typical sterility level for a medical device. one in a million germs/one in a million devices --- Edit: I'm going to unsticky this as i think this and my original removal reply are visible enough on their own by now.", "> I'd prefer not to have bacteria corpses on my hands, thanks. The irony here is that the human body contains just as much bacteria as our own cells. Not only that, but we are desperately dependent upon the bacteria that lives on our skin to protect us from all sorts of nastiness.", "So basically using germ-x is a waste of time and it's better to wash your hands?", "Objects can be made \"bacteria-corpse\" free with depyrogenation using gamma irradiation. Pyrogens are bacteria fragments left over after cell death. You cannot be depyrogenated, because you have bacteria that live with you all the time. They eat the dead ones when they find them, and they keep your outsides happy and healthy. If you lost them, you would end up with all kinds of horrible side effects because your microbiome (or personal bacteria ecosystem) is just as much a part of you as your own cells are.", "[Excellent answer from a few months back.]( URL_0 )", "Hand sanitizer kills bacteria by lysing cell membranes. You are quite literally cutting them open and spilling their juice all over you. By rubbing your hands together there is mechanical removal of bacteria, to some extent, but your best bet is to wash under water with soap. The soap will help lyse the cell, and allow the bacterial remnants to become suspended in water. Then, they should slide off, as running water does.", "don't worry, the dead bacteria will be very quickly eaten by the bacteria that survived, bringing forth a mini revolution of stronger hardier bacteria. Yes, you read that right. Hand sanitizers are bad for you and the world we live on. Never use hand sanitizers unless you've just touched something you are pretty sure had something contagious on it, or if you yourself have a contagious bacterial (viruses won't care about alcohol) illness and are about to cook for someone. In those cases, having less bacteria on your hand for a brief period is actually beneficial. Best way to stay healthily clean? soap. It'll get rid of the brunt of the gunk mechanically, not leave any corpses behind, and most importantly not give preferential treatment to the worst bacteria.", "The super bacteria feed on the corpses of its weaker brethren. It makes them stronger. We are only feeding the itty bitty beasts", "They are still there just dead. This reason is why antibacterial soap doesn't work as well as it sounds it should. Washing your hands actually removes bacteria from your hands, it may not kill it but it is a very effective method of sanitation for that reason.", "I'm sure someone else has already said it, but you're covered in and surrounded by dead bacteria all the time. Don't worry, you're used to it."], "text_urls": [[], ["https://redd.it/5640rc", "https://www.reddit.com/r/explainlikeimfive/about/rules#"], [], [], [], ["https://np.reddit.com/r/explainlikeimfive/comments/5640rc/eli5_if_bacteria_die_from_for_example_boiled/d8g5638/?st=j5cl6s7i&amp;sh=47fa9c1d"], [], [], [], [], []], "score": [1119, 703, 664, 108, 99, 77, 60, 49, 13, 9, 3]}}, {"q_id": "6ogkbb", "category": "Repost", "title": "Why does it seem to be such a custom here in the US to not list sales taxes on products?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkh6qlo", "dkh56zz", "dkh5ucm"], "text": ["It should also be mentioned that the US has a large group of people who are against the very concept of taxes. It's a popular opinion among anti-tax advocates that taxes, when they exist, should be itemized so that purchasers feel the burden of taxation directly. Many anti-tax advocates are against employer witholding, and wish to see changes to gasoline taxes so that taxes are also itemized there. With that in mind, a big part of the reason the US itemizes taxes is because doing so is politically popular, or at the least, attempts to change existing laws regarding them are *unpopular*.", "Because sales taxes are different everywhere. My State has a different rate than my neighboring States. Counties and cities have the option to tack on additional percentages, so it even varies from county to county, or city to city in the same county.", "Going alongside the different sales tax from state to state, there are often different or additional taxes for cities or regional areas. It would require different labels to be sent out per state and a different price advertisement per area (ex: different commercials, billboards, radio ads, etc) due to the possibility of being accused of false advertisement."], "text_urls": [[], [], []], "score": [6, 5, 5]}}, {"q_id": "6oilh4", "category": "Repost", "title": "Considering all of humanity's population EVER, why aren't there way more graveyards?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkhm2iz"], "text": ["The ground is hungry. Especially once you get back beyond modern preservation methods, barring special cases like mummification. Put a body in a wood coffin with metal adornments, in the ground, and depending on your soil and local environment, you can have nothing more than a discolored soil column with trace metal remains at the bottom in a number of years or decades. The rest of the body, the coffin, the clothes, it all decays. Lose the headstones, as has happened, and a graveyard may go entirely unnoticed by people, even if they are digging through it."], "text_urls": [[]], "score": [3]}}, {"q_id": "6okvnt", "category": "Repost", "title": "How do bugs in games occur?", "title_urls": {"url": []}, "selftext": "Are bugs that we see in games just error in the coding of the game? Are the errors things like typos?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dki51ia", "dki57l9", "dki50hl", "dki99js", "dkia1ee"], "text": ["Hallo, Computer Scientist here. Bugs are almost never typos, they can be, but this is rarely the case as if you just misspell a variable, for example, your code simply won't compile. Basically, you push Go! and the computer just laughs at you in this case. More often in any kind of software, not just games mind you, the code interacts in a way that the programmer didn't expect. For example, the programmer thought that some variable, X, could _never_ be a negative number. Then, when the code (game, in our case) is running, it ends up being a negative number, and the code interacts in a way the programmer never expected it to. This normally happens at a large level because several, if not dozens or even hundreds, of programmers are all writing on the same code, meaning they cannot possibly account for every single thing that could go wrong. Consider that your average major title, like GTA, Skyrim, etc, can be hundreds of thousands, if not _millions_ of lines of code. It's easy for something to go wrong. If you have further questions, lemme know :D", "> Are bugs that we see in games just error in the coding of the game? Yes. > Are the errors things like typos? No. If there's a typo in the actual code, the code won't run at all. Errors in the coding are mistakes in the structure of the code. You can generalize code to things like \"If X happens, do Y, unless Z is true, but if A and B are both false, and C is equal to D, then do Q instead.\" In reality, single statements aren't that convoluted, but it gives you some idea of what the complexity can be over dozens of lines of code. And when you're dealing with **millions** of lines of code, a single mistake can cause unexpected behavior.", "I wouldn't call them typos. The game or application has many code paths it can take based on user input. And in games there is a lot of user input. There is a Q/A team but they mostly test out the sane code path as a normal user would take. They cannot possibly test out all permutations. There will be odd cases which will uncover untested bits of code or high enough levels where they didn't anticipate anyone getting to.", "Typos in code are, correct me if I'm wrong, called syntax errors. Syntax in language is the structure of a sentence, following certain rules. A syntax error in programming can be something as simple as using an uppercase letter where you really shouldn't. Syntax errors will be reported to you by your compiler. They can be hard to find sometimes, they don't always stand out. Bugs are caused by what I have heard referred to as semantics errors. Semantics is the meaning of a sentence, the information the sentence is trying to convey. There's a famous bug in the early Civilisation games. The AI Gandhi was nuke crazy. It seems this is because the aggressiveness of the AI was based on a score of 1 to 250 or something. Gandhi had a low base aggression to start off with but also had these character traits that lowered it further into negative aggression, or what should have been negative aggression. They never programmed it for negative aggression so when Gandhi's score dropped below 0 it went all the way around back to around 250, back to the maximum score for aggression.", "As Zak pointed out, bugs are often the result of the code going through things that the developer never intended/expected. Like how hitting a certain block in Paper Mario billions of times, will crash the game, because the variable that stores how many times the block has been hit, overflows (goes over the limit for the amount of storage space it was allotted, and flips back to 0) and causes more blocks to spawn, eventually crashing the game due to too many objects in one area. The developers never expected you to hit that block 128,849,018,850 times, so the bug happens."], "text_urls": [[], [], [], [], []], "score": [77, 12, 6, 4, 3]}}, {"q_id": "6ol8hf", "category": "Repost", "title": "When a car is moving quickly, why does it appear like the wheels are rotating backwards?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dki8sf9"], "text": ["Your eyes and brain have a limit to how fast they can process information. They can only process a certain number of \"frames per second,\" and this works just like you would expect it to in a video or game. When you look at the world, your brain receives information like a picture. Then it receives a new picture, and processes the difference between the two, and that difference becomes our perception of motion. This happens again and again, and reality is just a series of still images. Your eye can process thousands of 'frames' each second, but for the sake of example lets say your eye is limited to 60 FPS. If a wheel is spinning at 1 rotation per second, and your eye is seeing at 60 fps, you will see 60 'images' of the wheel before it finishes a rotation. Each 'image' your eye captures the wheel has rotated 1/60th of a rotation forward. Your brain processes the difference between each of these 'images' and determines that the wheel is moving forward. If the wheel speeds up to 60 rotations per second, and your eye is seeing 60 fps, your eye will always 'capture' the wheel at the exact same moment in the spin, when it has made 60/60th of a rotation. Each 'image' your brain processes will have the wheel at the same position in the spin. It will be moving, but it will look as though it is stationary. If the wheel slows down to 59 rotations per second, and your eye is seeing 60 fps, your eye will always 'capture' the wheel at the point that it is 59/60th of a rotation. When your brain processes the difference between start position and 59/60 rotation it will make the wrong assumption that the wheel moved 1/60th of a rotation backwards rather than 59/60th of a rotation forward. All those 59/60th of a rotation happened while your eye was sending information to your brain, rather than receiving it from the world. Again, in reality your eye can process thousands of 'frames' each second, so the numbers in question are much larger. The principle is the same, though. Interestingly enough, if a wheel appears to be spinning backwards and you speed the wheel up it will once again look like it is going forward."], "text_urls": [[]], "score": [6]}}, {"q_id": "6olac4", "category": "Repost", "title": "Why is staring at the sun painful? What happens if you stare too long?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dki8km8"], "text": ["Your eyes have a focusing lens in front of them somewhat similar to a magnifying glass lens. Just like a magnifying glass, the lens will focus the sunlight tightly and begin to rapidly heat up whatever the light is focused on: in this case, onto the back of your eye, which is a very fragile tissue called the Retina. If you have ever watched someone burn a hole in paper or fry an ant with a magnifying glass, you will see how fast focused sunlight can cause damage."], "text_urls": [[]], "score": [14]}}, {"q_id": "6olf6h", "category": "Repost", "title": "why does air moving over your body, like from a fan, feel cold even though its no cooler than the regular air?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dki9vq2"], "text": ["The evaporation of perspiration from your skin makes the breeze feel cool. A smaller effect is direct heat transfer to the new air. Sidenote: the common admonition to \"wear a hat because your body loses most of its heat through your head\" is a confused lesson from military studies that compared heat loss with/without headgear. A person loses heat from all surfaces at about the same rate."], "text_urls": [[]], "score": [4]}}, {"q_id": "6olgt3", "category": "Repost", "title": "why is suicide generally not accepted?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkia5l8", "dkia4eq", "dkiacij"], "text": ["It's a permanent solution to a temporary problem. It's a messy thing for loved ones to try and understand.", "I feel like everyone has the right to kill themselves if they truly want to it's your life. Yes your leaving people behind and they might miss you but do you think that someone ready to end their life hasn't considered that already? Newsflash they have and if they still want to do it who is anyone to say that they shouldn't be allowed to.", "Suicide was always seen as a last means. Whether it was to exonerate your family name (see Ajax or the ritual of seppukku) or to help end your suffering (this has all sorts of extensions I won't get into). As a societal construct , humans believe that in all cases life is preferable to dieing , so our values and ethics, and even art , reflect this belief."], "text_urls": [[], [], []], "score": [8, 3, 3]}}, {"q_id": "6olle1", "category": "Repost", "title": "Why does video game animation look so much worse than movie animation/CGI?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkib216"], "text": ["Video games have to render each frame of animation in real time. For movies, they can spend hours rendering a single frame."], "text_urls": [[]], "score": [3]}}, {"q_id": "6omuve", "category": "Repost", "title": "Why is it that humans can eat the same thing for breakfast everyday without a fuss, but when it comes to Dinner/Tea/Supper it doesn't sit right?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkikcm3", "dkikb02", "dkikr15"], "text": ["That is not true for everyone. For many, myself included, eating the same thing for breakfast is just as unsettling as it is for any other meal. Everyone is different. There are some people who eat the same three meals every day with very little variance over time.", "I'm not sure this is true for everyone.. I'm often quite happy to eat the same lunch and dinner every day. Different folks different strokes I guess.", "Many cultures eat very similar meals for breakfast, lunch, and dinner. You simply have different expectations in yours."], "text_urls": [[], [], []], "score": [7, 6, 3]}}, {"q_id": "6on4b0", "category": "Repost", "title": "Why do batteries leak \"acid\" when they haven't been used for a long time?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkim5zu"], "text": ["Batteries produce electricity through a chemical reaction between an electrolyte and an electrode. In a lead acid battery, for example, these are sulphuric acid and lead respectively. As old batteries deteriorate - as old things tend to do - the acid can leak out."], "text_urls": [[]], "score": [7]}}, {"q_id": "6on5hk", "category": "Repost", "title": "Why does antisemitism refer only to the Jewish people even though the term \"Semite\" encompasses both Arabs and Jews?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkim2m3"], "text": ["Because the term was coined by people who used it to refer to groups that specifically hated Jews (Such as the Nazis), not groups that hated Jews and/or Arabs (For example, the Nazis got along pretty well with the Arab world, especially because of their shared antisemitism). URL_0"], "text_urls": [["https://www.ushmm.org/wlc/en/article.php?ModuleId=10005175"]], "score": [3]}}, {"q_id": "6oojn2", "category": "Repost", "title": "Labor Unions", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkiwh5e"], "text": ["All a union is is a group of workers who have banded together to engage in collective bargaining. The idea is that one worker asking for a raise or better benefits can be ignored or fired, while _all_ the workers asking have to be taken seriously. They help to balance the power between the workers and management. Now, some unions offer other services beyond this basic idea - some will offer insurance, pensions, unemployment, etc. - but their basic purpose is still the same."], "text_urls": [[]], "score": [3]}}, {"q_id": "6ooscp", "category": "Repost", "title": "Why do we have preferences for musical genres? Why can some people not stand listening to certain genres of music?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkj18a0", "dkj0ynx", "dkj0wse", "dkj3kf3", "dkj1hlt", "dkj0vm8", "dkj0vm2"], "text": ["Musical preference is very personal and highly emotional. Think about the music you like and listen to constantly? Why do you like it? The reasons for that are tied to your individual personal experience. You might like a genre because you grew up listening to it and its familiarity brings you comfort. Or because your parents hated it and you wanted to annoy the crap out of them because \"parents just don't understand\". Or because you friends like it and peer pressure was strong. Or because everyone hates and you want to go against the grain. ~~Musical like and dislikes are also tied to the way the sound waves affect your brain. Remember there are studies linking classical music and Mozart to higher cognitive function. Baby Einstein videos and baby TV programming is full of classical music scores.~~ Props to /u/nospr2 for pointing out that The Mozart Effect as this was known was debunked. As I responded to his comment this knowledge was so widespread that references to it made to pop culture which is why I remember it. [Link for those interested] ( URL_0 ) I personally dislike certain music genres solely because the sound hurts my ears. My hearing is sensitive to certain frequencies and downright deaf others. **Edit:** I updated my comment in reference to the Mozart Effect as it was pointed out that this was debunked. I also thought about what /u/thudly and /u/thefarivegone said below about musical preferences reflecting our ego and the image we want to present to the world and the way we see ourselves. His comment is [here] ( URL_1 ). With this in mind, I realize I dislike and dismiss certain musical genres because of the stereotypes and culture associated with each, for example, Bachata, Hip-Hop, Rap, and Reggaeton. At the same time, I also like specific songs and even artist that delve into each of these genres and gain a new appreciation for what **I considered \"good music\"**. Again showing that music like a lot of art is subjective and completely in the Eye or in this case Ear of the Beholder.", "Musical taste is subjective, everyone finds music enjoyable for specific reasons and a lot of that has to do with what you were exposed to growing up. People are both consciously and unconsciously conditioned to specific genres that they identify as enjoyable. As a result the genres they have always listened to are already associated with the positive feelings (Or negative if you like that sort of thing) they have when enjoying familiar sounds and styles. When a genre or sound that doesn't align with preconceptions of what the listener already enjoy, they are less likely to like music that contrasts with what they're already comfortable with. For me I like technical music coupled with thought provoking lyrics because it's what I've always listened to, it's my home base of comfort, so when I hear pop music and it's more of a simple more one track idea it's hard for me to like it because of my own preconceptions of what I expect enjoyable music to sound like. Hope that helps and wasn't too convoluted an answer!", "A bit of a disappointing answer and I'm sure some will state otherwise, musical taste is learnt. No one is born a metal fan yet as they delve into the mosher culture they start to mimic the peers' appreciations which in turn eventually become their own preferences. Edit: That's not to say that you don't here a pop song on the radio that you \"totally hate\" but secretly want to hear more often can't be attributed to appreciating aspects of a genre you claim dislike. Axis of Awesome did a great song example of this where they took 60 top of the charts songs from the last few decades and showed that they all used the same chord structure. I guess what I'm getting at here is that you can learn to appreciate a pattern even if you don't like it all the time. Edit: [Axis of Awesome - Four chord]( URL_0 )", "Part of it is human ego. People tend to form their identity around the things they like and believe in. Especially young people who are in the formative years and still figuring out who they are as a person. This is why people tend to develop the attitude that \"The things I like are the best, and everything else sucks!\" and if anybody criticizes their favorite thing, they take it as a personal attack, even though they have no real stake in the outcome of the dispute. Also, there's the [Mere-Exposure Effect]( URL_0 ) which basically makes things that are familiar more appealing. When you've heard a tune playing everywhere you go for a week or so, suddenly you get a jolt of dopamine (the feel-good chemical in your brain) from hearing it one day because you recognize it. It's the same mechanism that helps human beings learn any new thing. And then of course, things that aren't the same as what they're used to don't fire that dopamine, and it does nothing for them. It might even annoy them for various reasons.", "Until an individual loves their true self: social, peer, and media pressures shape their persona.", "I think it's something to do with our attraction mechanism, like how men and women have certain \"types\" of partners looks that they would prefer, then there are certain looks which are more generally attractive to each sex. Like how some pieces of art are generally attractive to a wide audience and some are more hit or miss. This same kind of philosophy I believe is applicable to musical genres, I theorize it revolves around our genetics and how our ears and eyes react to stimulus in our environment. Kinda like how some people prefer alcohol to weed, and vice versa. The way our brain processes input seems to be the biggest factor. Open to discussion though, hopefully someone can come through with some sources and or a better theory.", "Musical preferences are normally derived from your cultural backgrounds. Things like what your family and friends listened too. What kind of music you hear at your religious institution. Also what country you came from. All of these factors as well as many others can play a role in what kind of music your prefer."], "text_urls": [["https://www.sciencedaily.com/releases/2010/05/100510075415.htm", "https://www.reddit.com/r/explainlikeimfive/comments/6ooscp/eli5_why_do_we_have_preferences_for_musical/dkj3kf3/"], [], ["https://www.youtube.com/watch?v=5pidokakU4I"], ["https://en.wikipedia.org/wiki/Mere-exposure_effect"], [], [], []], "score": [154, 11, 9, 9, 7, 4, 3]}}, {"q_id": "6oot0m", "category": "Repost", "title": "If you looked through a telescope to mirrors far into space could you theoretically look back in time?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkiyuza", "dkiz3k3"], "text": ["You are looking back in time if you look at a mirror in your bathroom. Just... not very far back in time. The image you are seeing, is made from light that traveled from its 'source' (whatever the image is) to the mirror, and then from the mirror, to your eyes. The travel time is how old that image is. So if a mirror is 1 light year away, and we ignore all the difficulties in being able to see an image in a mirror at that distance, and you saw your reflection, it'd be a scene from 2 years ago (1 year to the mirror, 1 year back). Bear in mind, you couldn't see the distant past, since your mirror would have to get there at slower than light speed. That means that even at the fastest possible velocity, you could only ever see scenes from after the Mirror had 'taken off' from Earth, because all the light reflecting off the earth *before* that time, would beat the mirror to where you set it up, and be further out in space. Of course, you don't need a mirror for this, any object you are looking at from a distance, you are seeing out of date by the travel time of the light. Of course, in our daily lives, this difference is unnoticeable.", "Yes. A mirror seven light years away would show you an image of Earth 14 years ago. Really any time you're looking into deep space you're already looking \"back in time\" because that light has been in transit for years. Of course you would need an unreasonably powerful telescope to see the reflection of earth in a tiny mirror several light years away, and it would take you much more than seven years to get the mirror into position, and seven more years before Earth detects the signal. You can't outrun the light you just emitted so you'll never be able to see back before you completed the mirror project."], "text_urls": [[], []], "score": [6, 3]}}, {"q_id": "6opmwm", "category": "Repost", "title": "Why do planes go up to 20,000 to 30,000 feet?", "title_urls": {"url": []}, "selftext": "Couldn't they just go up to 1000 feet? Is it somehow more cost effective to be at a higher altitude?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkj6i6j", "dkj5zjc"], "text": ["Several reasons, off the top of my head. 1. Air is thinner at higher altitudes. That means considerably less drag on the airplane, so higher efficiency. 2. Ever heard the phrase \"speed is life, altitude is life insurance?\" It's typically a fighter plane saying, but the second part definitely applies here. Suppose you had multiple engine failures on your plane and had to make an emergency landing. If you're only 1000 feet in the air, that means you can coast maybe a few miles before you run out of time and crash. When you're six miles up, you've got a lot more time to call to the nearest air traffic controller, identify potential runway options (other airports, etc.) and get there before you crash. 3. The jet streams are up at those altitudes. A jet stream is a very fast-moving current of air that moves around the globe in a steady, predictable pattern. A lot of long airplane routes count on catching a particular jet stream. It's the difference between paddling your canoe with the river's current instead of paddling your canoe across a still lake.", "> Is it somehow more cost effective to be at a higher altitude? Yes, higher altitudes have thinner air, reducing the drag on the airplane, and improve the odds of flying above bad weather."], "text_urls": [[], []], "score": [20, 9]}}, {"q_id": "6oqeyg", "category": "Repost", "title": "If heat rises, then why does it get colder as you get higher on mountains?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkjcy53", "dkjd03s"], "text": ["As hot air rises, it expands. As air expands, it cools. It's hottest at the ground, because the air is heated primarily by the sun warming the surface.", "Because air expands as it reaches areas of less pressure (altitude), and expanding air cools down. Changes in heat with pressure are exactly how air conditioners, fridges, etc work. They compress \"air\" (actually a special chemical) so it gets hot, dump the heat outside where it isn't wanted, then let it expand and therefore cool, next to the area where you want it cold. Air doesn't \"un-rise\" when it cools because the lower pressure means it can cool without actually becoming heavier-- the actual reason it would rise/sink in the first place."], "text_urls": [[], []], "score": [3, 3]}}, {"q_id": "6ot8y4", "category": "Repost", "title": "Why is there such a drastic mood change when the guy ejaculates?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkk7ov3", "dkk1x11", "dkk1xts", "dkk9k7x"], "text": ["What you're referring to is often called the \"[refractory period]( URL_0 )\" which is (mostly) very short for women and (mostly) much more pronounced for men. This is just biology - while you can't blame guys (or girls) for how our biology encourages us to behave, we can obviously be aware of it and treat each other lovingly and sensitively, being aware of how our bodies and brains naturally work. I believe this should really be explained to all girls (and guys) about how our sexual behaviour is so different. It's been a bone (ho ho) of contention for as long as cultural expectations have existed. Simply put, guys' physiology - which *includes* our emotional responses - are wired to drive very very intense sexual attraction until orgasm, and then be able to go off and do something else, like resume hunting for wilderbeast. You don't want men spending all their time shagging, and not doing other important stuff like defending from predators and killing each other. We guys are simply not biologically wired to \"bond\" over sex as such. We do bond over other things - do some googling about what triggers *oxytocin* (the bonding hormone) in men. Sexually speaking, we are wired to try and be attractive to females (often by exhibiting valuable physical skills or social dominance) and pass on our genes to females as \"efficiently\" as possible. That said, culture of course does play an enormous role in how we behave, above and beyond the necessities. Even though guys' brains aren't rewarded for post-coital smooching, culture and personal learning can alter that \"default\" behaviour, to quite a large extent. So if your current guy isn't making a lot of effort, chances are he hasn't learned why he \"should\" (in terms of your expectations). If you're unhappy, communicate to him about it, or find someone else if that doesn't work. Once you understand the \"why\", the decision and your happiness (at least in modern culture) is up to you. If you live in a very male-dominated culture, sadly it might not be and men are less interested in changing their behaviour.", "The reason that guys get mood changes whenever they have climaxed is because ejaculation releases the chemical called dopamine into your brain, which is sort of the essence of happiness. The dopamine covers feelings of stress, worry, and anger. Not only that, but other endorphins are released into the body that can sort of reduce the perception of pain.", "The Japanese have concocted a word for this - [Kenjatime]( URL_0 ).", "Realease of prolactin and cortisol, mainly. Prolactin destroys testosterone and cortisol makes you feel irritable and hungry. And longing for a smoke too! All of this to prevent we fuck until our heart fails."], "text_urls": [["https://youtu.be/Qymp_VaFo9M?t=284"], [], ["https://www.jlect.com/entry/2891/kenjataimu-kenjataimu/"], []], "score": [63, 25, 9, 7]}}, {"q_id": "6otrmm", "category": "Repost", "title": "How do antidepressants work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkk7afi"], "text": ["Everything we think, feel, and sense is the on some level the result of electrical signals in our brains. Those signals are created when chemicals called neurotransmitters interact with neurons. There are many different kinds of electrical pathways in our brains, and many different neurotransmitters that trigger them... some are involved in the business of running our bodies, but two are also in the business of making us feel good: dopamine and serotonin. Dopamine is used in \"[reward system]( URL_1 )\" pathways in our brains, which fire when we are doing/experiencing things that are likely to keep us healthy and alive and able to pass on our genes: eating, drinking, sexing, caring... our brains 'reward' us for doing these things by releasing dopamine, which triggers specific pathways that make us feel good so we will likely do those things again. This is the chemical basis of learning, and also the chemical basis for addiction. Serotonin is mostly involved in regulating our gastrointestinal tract, but it also triggers pathways in the brain that make us feel good in response to our \"[perceived abundance or scarcity of resources]( URL_0 )\"... this is why we feel content when our basic needs (food, clothing, shelter, and companionship) are met, and why we feel like crap when they aren't. But dopamine and serotonin can only do their thing in our brains if there is enough dopamine and serotonin available, and some people have brains that don't produce enough of them. Those 'feel good' pathways aren't triggered, or aren't triggered *enough*, so the person is literally unable to experience the good feelings associated with things that should make them feel good. Most antidepressants block the breakdown of serotonin and/or dopamine, keeping more of it available *if* it is needed (i.e. this isn't the same as making the person feel good, there is just increased availability of the neurotransmitters that can *allow* the person to feel good naturally if the things that trigger good feelings happen). This highlights the difference between clinical depression and just not feeling good: when there is a lack of comforting stimuli, not feeling good is a reasonable response; when a person is literally incapable of feeling good even when there *are* comforting stimuli, that can be a medical problem."], "text_urls": [["https://en.wikipedia.org/wiki/Serotonin#Functions", "https://en.wikipedia.org/wiki/Reward_system"]], "score": [11]}}, {"q_id": "6ouyvw", "category": "Repost", "title": "why does our voice sound different to us compared to how others hear it?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkkdsxk"], "text": ["You hear your voice differently because you aren't just hearing the sound waves that go in your ear. You're also hearing the vibrations that travel through your skull. Since bone is denser than air the vibrations travel at a different speed and are therefore heard differently by you than other people hear them."], "text_urls": [[]], "score": [4]}}, {"q_id": "6ov6vq", "category": "Repost", "title": "What's the science behind waking up in the middle of the night after only a few hours of sleep feeling rested, only to get a full eight and wake up tired?", "title_urls": {"url": []}, "selftext": "Example: Falling asleep at 9pm, waking up at 1am to go to the bathroom feeling well rested, but feeling the need for more sleep when the alarm goes off at 5am.", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkkhgbj", "dkkfrnp", "dkkh800", "dkkh1b5", "dkkh7hw", "dkkfhk9", "dkkler1", "dkkh89y"], "text": ["Sleep stages. There are 5 different sleep stages; * the 'on-ramp', you know when you're at the back of a boring class / lecture and your head starts nodding, literally 'falling asleep' as it feels like you've fallen if you catch yourself. * stage 2, your brain waves start to slow down (iirc waking, your brain has a 'frequency' of ~20 cycles per second, as this slows you become more relaxed and eventually fall asleep) * stage 3, this is 'deep sleep', usually the period where people experience erratic sleep behaviour such as sleepwalking, wetting the bed etc * stage 4, now your brain is pretty much only producing delta waves, frequency of around 1-4 cycles per second... so slooooow! If you are woken from this stage, you will feel VERY groggy and disoriented * and stage 5, the stage we all know so well... REM sleep! AFAIK, it's the 15 mins of REM sleep per hour which 'refresh' you. If you don't get REM time, you will not feel like you've slept properly. This is why we feel so ughhhhhh after drinking, because alcohol interrupts this important stage. Hangover = dehydration multiplied by being horribly sleep deprived. On that note, my hangover cure? Get up, drink a pint of water, have something nourishing, then go back to sleep for a couple of hours.", "With an alarm you are interrupting a sleep cycle. Waking up naturally will be more refreshing because you come out of the end of a cycle. If you wake up at 8 hours naturally without an alarm and you'll be just as refreshed as your 1am wake up.", "Your sleep cycles are roughly 90 minutes in length. If you set your clock for a time that will be at one of the 90 minute increments from when you actually go t sleep, it will be much easier to get started on your day. For example, if you need to get up at 7:00 am, and can get to sleep by 12:30 am, you are better off setting your alarm for 6:30 because the alarm will go off as you are emerging out of your fourth 90 minutes sleep cycle of the night. By 7:00, you would be fairly deep into your fifth sleep cycle and woule feel tired and groggy.", "As the other posts said, it is about when you wake up during your cycle of sleep. If you want to time when you wake up or when to go to sleep based on the sleep cycle you can use URL_0 to calculate it. It helps you wake up feeling more awake and refreshed instead of tired and groggy.", "Yup. Look into getting a sleep sensing alarm- I use one on my iPhone called Sleep Cycle that purports to be able to detect where you are in your sleep cycles and wake you up closest to your natural waking point, within half an hour of your alarm (set alarm for 6am, it will wake you up between 5:30-6 depending on where it thinks you are closest to already waking). Has two sensing modes, movement based (need to have it on the bed with you) and a newer audio based one (need to have it pointed at you on a nightstand next to the bed). Both modes defiantly seem to work much more pleasantly than a traditional alarm clock- it also has some \"gentle\" wake up noises (I do birdsong. Not startling, but loud enough and unusual enough that for me, it wakes me up, especially when I'm close to being awake) The only trick is that our typical REM sleep cycles are about 3 hours from almost awake to deep sleep, so depending on when you go to sleep, that half hour waking window may still have you in pretty deep sleep, so it's best to try and get yourself to sleep in a time frame that syncs up with when you need to wake up.", "When one sleeps, his body goes through various cycles. Waking up during/after certain cycles will leave one refreshed, yet during others, one feels tired. Just depends during which cycle one wakes up.", "For men, testosterone levels are naturally at their highest levels in the morning. Men with low T tend to consistently feel tired when they wake up, no matter how much sleep they get.", "Having done quite a bit of reading for my own benefit I think I can provide a bit more information. If you break down sleep to 4 categories, each is a deeper stage of sleep and being woken up in stages 3 or 4 can leave you feeling disorientated and groggy as your body has essentially shut down parts that are unnecessary for recovery during sleep. Bonus info, sleep trackers have a feature that wakes you in the lightest stage of your sleep before your target time, leaving you as refreshed as possible."], "text_urls": [[], [], [], ["www.sleepyti.me"], [], [], [], []], "score": [358, 88, 61, 28, 10, 3, 3, 3]}}, {"q_id": "6ovkcl", "category": "Repost", "title": "What's actually happening physiologically when for example your muscles or ankle is sore the next day after hiking, and it \"hurts so good\" when you massage it or put pressure on it?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkkkou0"], "text": ["The sensory nerves for \"touch\" have a stronger signal than the \"pain\" receptors so you get temporary relief."], "text_urls": [[]], "score": [3]}}, {"q_id": "6ovp1q", "category": "Repost", "title": "How do trees know when it's been a year, to grow a new ring?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkkjosh"], "text": ["They don't really decide to grow a new ring. They grow faster in the summer than they do in the winter as there's more sunlight, so the wood from the winter is denser and darker. Each dark ring in the tree shows that the tree has lived through a winter."], "text_urls": [[]], "score": [9]}}, {"q_id": "6ox6dl", "category": "Repost", "title": "Why can humans not digest fiber?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkkx6ai"], "text": ["There are actually almost no animals that can digest fibers! Almost all animals who live off stuff like leaves and grass break them down with the help of symbiotic bacteria that live in their intestines. Humans only have a tiny number of bacteria than can break down cellulose, and they only break down enough of it to feed themselves. As for *why* we don't have these bacteria: probably because digesting that kind of food is not very efficient and you don't get a lot of energy out of it (for instance, I happen to have in my head that guinea pigs get about 40 kcal out of 100 g of hay). With a big energy-hungry brain like ours, it's better to have a digestive tract optimised for energy-dense foods like meat, fruit and starchy things, rather than one that'll be welcoming to cellulose-eating bacteria."], "text_urls": [[]], "score": [6]}}, {"q_id": "6oxdlj", "category": "Repost", "title": "Who decided to make all barns red and what is the purpose of all barns being red? Drove down farm roads of Indiana the other day and every single barn was red and it spawned this question for me", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkkxg4f", "dkkxjyh", "dkkxg4z"], "text": ["Nobody cares about the color of the barn. Just as long as it is painted. And with a big barn to cover the farmers order the cheapest paint they can get. The color of the paint comes from various different pigments that is added. So the price of paint is dependent on the price of the pigment. The cheapest pigment is iron oxide as it is found everywhere in the dirt. Iron oxide give a nice red color.", "Looks like every question I ever will have will be answered by Reddit. Thanks!", "Yer not alone in askin', and kind strangers have explained: 1. [ELI5: Why are barns usually red? ]( URL_1 ) 1. [ELI5: Why are so many barns painted red? ]( URL_0 ) 1. [ELI5: Why are barns always painted red? ]( URL_6 ) 1. [ELI5: Why are the majority of barns red? ]( URL_4 ) 1. [ELI5: Why is red such a common color for barns? ]( URL_2 ) 1. [Why are barns painted red? ]( URL_3 ) 1. [ELI5: Why is the universal color for barns red? ]( URL_5 )"], "text_urls": [[], [], ["https://www.reddit.com/r/explainlikeimfive/comments/67crxj/eli5_why_are_so_many_barns_painted_red/", "https://www.reddit.com/r/explainlikeimfive/comments/2lvmaq/eli5_why_are_barns_usually_red/", "https://www.reddit.com/r/explainlikeimfive/comments/3z6i9r/eli5_why_is_red_such_a_common_color_for_barns/", "https://www.reddit.com/r/explainlikeimfive/comments/1jmhsa/why_are_barns_painted_red/", "https://www.reddit.com/r/explainlikeimfive/comments/3mldmd/eli5_why_are_the_majority_of_barns_red/", "https://www.reddit.com/r/explainlikeimfive/comments/4tbluj/eli5_why_is_the_universal_color_for_barns_red/", "https://www.reddit.com/r/explainlikeimfive/comments/zceo3/eli5_why_are_barns_always_painted_red/"]], "score": [7, 3, 3]}}, {"q_id": "6oxnp5", "category": "Repost", "title": "what makes sticky things sticky?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkl1byr"], "text": ["Yer not alone in askin', and kind strangers have explained: 1. [ELI5: What makes something sticky? ]( URL_7 ) 1. [ELI5, What makes things sticky? ]( URL_1 ) 1. [ELI5: Why are sticky things sticky? ]( URL_6 ) 1. [What makes sticky things...sticky? ]( URL_2 ) 1. [ELI5 why are things \"sticky\"? ]( URL_3 ) 1. [ELI5: What makes things sticky like glue? ]( URL_4 ) 1. [ELI5: Why are things sticky? ]( URL_0 ) 1. [ELI5: what causes something to be sticky? What is happening at the atomic level? ]( URL_5 )"], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/45r17w/eli5_why_are_things_sticky/", "https://www.reddit.com/r/explainlikeimfive/comments/126g4y/eli5_what_makes_things_sticky/", "https://www.reddit.com/r/NoStupidQuestions/comments/3kl2to/what_makes_sticky_thingssticky/", "https://www.reddit.com/r/explainlikeimfive/comments/5bje0s/eli5_why_are_things_sticky/", "https://www.reddit.com/r/explainlikeimfive/comments/2hc0jc/eli5_what_makes_things_sticky_like_glue/", "https://www.reddit.com/r/explainlikeimfive/comments/3hr3v5/eli5_what_causes_something_to_be_sticky_what_is/", "https://www.reddit.com/r/explainlikeimfive/comments/t3txk/eli5_why_are_sticky_things_sticky/", "https://www.reddit.com/r/explainlikeimfive/comments/4op11k/eli5_what_makes_something_sticky/"]], "score": [7]}}, {"q_id": "6oyr98", "category": "Repost", "title": "Most of the symptoms you hear of from cancer patients are actually symptoms of the treatments they are going through. So what are the actual symptoms of cancer and how does cancer destroy the human body?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkld035"], "text": ["This is a tough question because there are hundreds of known cancers, and theoretically infinite unknown cancers. Each is as different as one species of bird is different from another species of bird. That is to say they share some characteristics, but individual types of cancers can have distict attributes as well as individual cases of each cancer can have subtle differences. The main connection of all cancers is that they are cells which no longer respect the rules and requests of the host organism. They are rogue cells. Almost a different entity forming inside the host. Since they don't play by the rules, they can wreak havok on those around them. When some bad cancer cells move into town you could say the neighborhood goes to shit. If it's bowl cancer you may lose the ability to handle waste, killing you from we toxicity. If it's stomach cancer you may become unable to eat or digest food. Starving you to death. Cancer also had a tendency to stop respecting it's original role also. Stomach cancer cells may make it into your blood stream, land in your heart, and just stay growing there. They don't care. It's warm and there is food. Kind of like homeless people setting up a camp in the downtown. They steal bikes, shit everywhere, and drop their needless wherever they want. Eventually killing the area around them. Meanwhile, your body sometimes recognized them as a post and attached then, other times it see them as regular citizens and continues protecting them. Hope that helps."], "text_urls": [[]], "score": [3]}}, {"q_id": "6ozckt", "category": "Repost", "title": "Why exactly does moving air feel cooler?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkleyn2"], "text": ["It's the process of convection that is improving your body's ability to cool off. There are three types of heat transfer: conduction, convection, and radiation. Convection is where the heat from your body warms the air in immediate contact. Normally that warmed air would stay close to you. But with the with air flowing, new, cooler air is constantly moving into place to absorb that heat from your body. So, moving air creates another avenue for heat to leave the body in addition to its usual processes. It's been a few years since I was in a physics class. I'm sure someone else can explain it better or make some corrections, but that's the gist of it. Edit for spelling"], "text_urls": [[]], "score": [11]}}, {"q_id": "6p0db8", "category": "Repost", "title": "How can speakers both sound like a piano, a guitar, and human voice?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dklp4ym"], "text": ["Yer not alone in askin', and kind strangers have explained: 1. [ELI5: How do speakers virtually produce any sound? ]( URL_4 ) 1. [ELI5: How do speakers work? My brain just can't comprehend how all the sounds and frequencies at one single point in a song (drums, vocals, guitar, etc) can be created by one single vibration of a membrane. All at once ]( URL_1 ) 1. [ELI5: How do speakers make sound? ]( URL_2 ) 1. [ELI5: How come speakers can produce a plethora of pitches and sounds, but our voices can only produce one pitch at a time? ]( URL_3 ) 1. [ELI5 how speakers work, and specifically, how they play multiple different sounds simaltaneously ]( URL_0 )"], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/mgjz5/eli5_how_speakers_work_and_specifically_how_they/", "https://www.reddit.com/r/explainlikeimfive/comments/3sa439/eli5_how_do_speakers_work_my_brain_just_cant/", "https://www.reddit.com/r/explainlikeimfive/comments/4qjo7q/eli5_how_do_speakers_make_sound/", "https://www.reddit.com/r/explainlikeimfive/comments/2c27ri/eli5_how_come_speakers_can_produce_a_plethora_of/", "https://www.reddit.com/r/explainlikeimfive/comments/1jxp9q/eli5_how_do_speakers_virtually_produce_any_sound/"]], "score": [4]}}, {"q_id": "6p0z3a", "category": "Repost", "title": "What would happen if they didn't remove our umbilical cords/placentas at birth?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dklql54"], "text": ["They would dry up and fall off in a couple of days...just like the umbilical stub does. If you have ever been around a newborn, they still have a little of the cord attached. It naturally dies and falls off in a few days."], "text_urls": [[]], "score": [4]}}, {"q_id": "6p2a8l", "category": "Repost", "title": "Why when something quotes old documents, is only the first letter of the quote in brackets?", "title_urls": {"url": []}, "selftext": "For example, the book I'm reading now has the following quote: \"[I]t is a pity to spoil a good mate by making him a master\"", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkm0eqi"], "text": ["I think that happens when they begin the quote midway through the original sentence, so the bracket indicates that the first letter isn't quite the same as in the source, because they capitalized it."], "text_urls": [[]], "score": [11]}}, {"q_id": "6p47oe", "category": "Repost", "title": "Why are clouds grey when raining, but white otherwise?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkmfr0l", "dkmj3gr"], "text": ["Thickness. When clouds hold a load of moisture, they appear darker. When they are whiter, they don't have as much moisture, so they aren't dark. If you see a green one, or greenish one, that means it is holding a lot of hail aloft. The sunshine acts as a prism and the light is bending towards the green.", "Yer not alone in askin', and kind strangers have explained: 1. [ELI5 - why do clouds turn dark before they rain? ]( URL_2 ) 1. [ELI5: why are rain clouds grey, and normal clouds white? ]( URL_6 ) 1. [ELI5: Why are storm/rain clouds grey instead of white? ]( URL_0 ) 1. [ELI5 Why clouds turn grey when it's going to rain ]( URL_4 ) 1. [ELI5: Why are rain clouds darker than regular clouds if water is clear? ]( URL_1 ) 1. [ELI5:Why do clouds become dark/gloomy when it's raining? ]( URL_3 ) 1. [ELI5:Why do clouds turn grey when it's about to rain? ]( URL_5 )"], "text_urls": [[], ["https://www.reddit.com/r/explainlikeimfive/comments/16gu58/eli5_why_are_stormrain_clouds_grey_instead_of/", "https://www.reddit.com/r/explainlikeimfive/comments/2it1ni/eli5_why_are_rain_clouds_darker_than_regular/", "https://www.reddit.com/r/explainlikeimfive/comments/64rfs2/eli5_why_do_clouds_turn_dark_before_they_rain/", "https://www.reddit.com/r/explainlikeimfive/comments/3il1jh/eli5why_do_clouds_become_darkgloomy_when_its/", "https://www.reddit.com/r/explainlikeimfive/comments/1e2je1/eli5_why_clouds_turn_grey_when_its_going_to_rain/", "https://www.reddit.com/r/explainlikeimfive/comments/2akn32/eli5why_do_clouds_turn_grey_when_its_about_to_rain/", "https://www.reddit.com/r/explainlikeimfive/comments/1n5gno/eli5_why_are_rain_clouds_grey_and_normal_clouds/"]], "score": [5, 3]}}, {"q_id": "6p57wu", "category": "Repost", "title": "How do buffet restaurants make profit?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkmoxr6"], "text": ["They make food cheaply and charge more than what most people eat. Most people will have 2-3 servings. They generally charge enough to pay for 5-6, thus the few that eat more than 6 are more than compensated for."], "text_urls": [[]], "score": [12]}}, {"q_id": "6p58ck", "category": "Repost", "title": "Why do people occasionally shiver while they are urinating?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkmpt68"], "text": ["This is hard to explain like you're five, but the answer is that the part of your nervous system involved in sensing the need to urinate, is also related to the part that makes you feel \"shivers\" and it's being strongly stimulated by the contractions and emptying of the bladder."], "text_urls": [[]], "score": [10]}}, {"q_id": "6p5zwb", "category": "Repost", "title": "How do doctors, nurses, etc. tend to sick people constantly without getting sick all the time themselves?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkmxf70", "dkmvlum", "dkmvsmf"], "text": ["Hello! This is a great question, and something healthcare staff should always keep in mind when working around patients. Depending on what the patient's diagnosis is, different precautions are taken. Staff wear disposable **personal protective equipment (PPE)** based on protocol. & nbsp; A **standard or universal precaution** is applied to every patient, even if they do not have an infectious diagnosis. This involves basics like hand washing/sanitizing before and after contact, as well as gloves. You never know what someone has, so it is best to play it safe when coming in contact with potential disease vectors like blood and vomit. Patients with a **contact**-spread disease, e.g. norovirus, are designated as such and given adequate isolation to prevent transmitting the disease to another patient. This can be a private room or sharing a room with a patient diagnosed with the same infection. Staff wear disposable gowns as well as the aforementioned gloves. All equipment brought into the room is cleaned, or the room will preferably have its own set of equipment. Diseases spread through droplets up to 3 feet, whether by coughing or sneezing, such as influenza, require **droplet precautions**. A surgical mask prevents inhalation of these droplets, and often staff will also wear contact PPE if getting close to the patient Varicella (chicken pox) and measles, etc. are spread similarly, but form small particles that can travel further and penetrate surgical masks. In preparation for **airborne precautions**, staff are fit-tested with N95 respirators early on. Sometimes, things go wrong, even with the most skilled professionals. Hospitals have policies and procedures to dictate how to handle things like accidental needle-sticks to prevent transmission of disease. & nbsp; I hope this helps!", "They take precautions against illness when treating others, including near religious handwashing, facemasks, sterile and single use equipment, and in extreme situations, quarantine procedures.", "Im an ER doctor. I got sick all of the time x 10 years. I just took a year off and didn't get sick at all. It's prompted some soul searching."], "text_urls": [[], [], []], "score": [12, 4, 4]}}, {"q_id": "6p6069", "category": "Repost", "title": "Why do guys get random erections?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkmvpdp"], "text": ["Sexually mature men can control their arousal. During puberty, hormones are all over the place causing all spontaneous arousal, etc."], "text_urls": [[]], "score": [4]}}, {"q_id": "6p613v", "category": "Repost", "title": "Why isn't there lightning during snowstorms?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkmw44r"], "text": ["There is lightning during some snowstorms, thunder as well. I saw it during a blizzard in Flagstaff, AZ in the winter of 2009. I have attached a youtube link as well showing it from someplace up north. Cue up to around 1:34. URL_0 Hope that helps."], "text_urls": [["https://youtu.be/nefLipXk36o"]], "score": [6]}}, {"q_id": "6p6nb3", "category": "Repost", "title": "why does nasal congestion switch sides when you're laying down and then roll over?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkn0urz"], "text": ["Behind your nose is a large cavity. It's filled with mucus when you're congested. It's really otherwise completely empty (filled with air). So, if you roll over, all the mucus just stays \"down\". Gravity."], "text_urls": [[]], "score": [5]}}, {"q_id": "6p8gzr", "category": "Repost", "title": "Why is there a 'D' in fridge but not in refrigerator?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkncogv"], "text": ["That \"d\" was hammered into the word \"frige\" to help it sort-of look like how it's pronounced. \"Frig\" would look like it sounds like \"rig\", \"frige\" would have a long \"i\", and \"fridge\" looks like it rhymes with \"ridge\". Refrigerator comes from the Latin refrigeratus, which is why it has no \"d\"."], "text_urls": [[]], "score": [9]}}, {"q_id": "6p8vhr", "category": "Repost", "title": "How do airplane pilots know that turbulence is ahead?", "title_urls": {"url": []}, "selftext": "Are they just reading weather radar and the potential of turbulence, reports from past planes, or do they have sensors that measure air pressure and what-not? Thanks in advance!", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkngb57"], "text": ["If they are so-equipped, pilots are trained to interpret the returns on forward-looking weather radar that would indicate the potential for turbulence ahead. Additionally, if they are on an instrument flight plan (and most commercial flights are), they will be in contact with the ARTCC (Air Route Traffic Control Center), who will relay reports of other aircraft that have just traversed the area they are approaching, and will relay the information, along with recommended courses and altitudes to avoid the turbulence."], "text_urls": [[]], "score": [4]}}, {"q_id": "6pay07", "category": "Repost", "title": "Why does our urge to go to the bathroom grow the closer we get to the toilet?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dknzcqy"], "text": ["Can't really explain better than this URL_0 > Most of what your brain and nervous system does is not conscious. What you control and perceive is only a small fraction of what your brain is doing day in and day out to keep you alive. Altering hormone levels, controlling your breathing, monitoring your energy levels, etc. It's like your computer. What you see on the screen or control with the mouse is only a small part of what the computer is doing behind the scenes. In fact this part of your brain is mostly oblivious to what you are 'thinking'. > One of those things, whether you consciously notice or not, is remaining constantly aware of your environment. Your brain is taking everything in and comparing it to past experience or innate instinct. So when you walk by your favorite restaurant your brain assesses your energy levels and if they are at all low says, hmmm, this could be a good time to restock, we don't know when we might find food again. So pretty soon your tummy is rumbling away because your brain simply cannot trust you to make the right decisions without some influence. Remember, our brains evolved in a much different environment than many of us live in now. One that was much less forgiving of missing chances to eat, drink, etc. > Peeing is no different. Your brain has been keeping an eye on how full your bladder is and giving you low intensity warnings that it is getting up there. But when your brain knows you are by a place where you can solve that problem, it ups those warnings so you have no choice but to take advantage. It has no way of knowing that you are going to the bathroom already, it just sees the stimulus and issues the response. > This normally works pretty well, but it can go haywire. Things like phobias, PTSD, and other conditions often result from the brain getting a stimulus-response relationship wrong. So a soldier in a war gets blown up by a roadside bomb and even when they are back in the safety of their homeland their brain cannot let go of the idea that a pile of rocks by the road could be a major threat. So they go into full threat mode when driving to the store or out for a walk. > So be happy that your brain has the peeing response right! Better the bathroom than something less convenient Edit : I have to ad , there are \"2 parts\" in you brain , sympathetic and parasympathetic. The sympathetic is what will act in cases of stress (someone is outside the bathroom door , you might find it hard to pee/poop because you are stressed ) , parasympathetic system does the opposite and will relax you instead (if you are going alone to the bathroom will be easier to do it , esp if you get closer)"], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/14fz47/eli5_why_does_my_urge_to_pee_intensify_as_i_get/c7cs17a/"]], "score": [8]}}, {"q_id": "6pc1yv", "category": "Repost", "title": "Why can you not smell an odour that your body is producing anywhere near as strong as other people can?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dko685i", "dkodggq"], "text": ["In the simplest of terms, the same reason you don't feel your clothes all day long or you don't see your nose all the time. Your brain starts ignoring constant stimuli after a while because it assumes it's safe so it diverts resources towards looking for new stimuli/sources of danger.", "Yer not alone in askin', and kind strangers have explained: 1. [ELI5: Why can't people seem to smell their own body odor when it's over-powering to everyone within nose-shot? ]( URL_0 ) 1. [ELI5: Why cant we smell our own body odor? ]( URL_3 ) 1. [ELI5: Why do our own body odors don't smell as bad to us as other people odors do? ]( URL_2 ) 1. [ELI5: Why can't we smell ourselves well? ]( URL_1 )"], "text_urls": [[], ["https://www.reddit.com/r/explainlikeimfive/comments/1imdc9/eli5_why_cant_people_seem_to_smell_their_own_body/", "https://www.reddit.com/r/explainlikeimfive/comments/3fzuto/eli5_why_cant_we_smell_ourselves_well/", "https://www.reddit.com/r/explainlikeimfive/comments/2o3oww/eli5_why_do_our_own_body_odors_dont_smell_as_bad/", "https://www.reddit.com/r/explainlikeimfive/comments/3fz76m/eli5_why_cant_we_smell_our_own_body_odor/"]], "score": [14, 3]}}, {"q_id": "6pcxop", "category": "Repost", "title": "Why aren't people attracted to family members?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkodb4j", "dkodiqp"], "text": ["I mean they can be, incest is a thing. But if you want an evolutionary explanation, incest can often lead to severe birth defects in children and as a result, it is evolutionarily beneficial to have a hardwired response to avoid that. And that is likely what happened (I say likely because all current evidence seems to be anecdotal).", "Yer not alone in askin', and kind strangers have explained: 1. [ELI5: How come siblings are not attracted to each other? ]( URL_0 ) 1. [Why are people not attracted to their siblings? ]( URL_1 )"], "text_urls": [[], ["https://www.reddit.com/r/explainlikeimfive/comments/5mjr7u/eli5_how_come_siblings_are_not_attracted_to_each/", "https://www.reddit.com/r/NoStupidQuestions/comments/52arkg/why_are_people_not_attracted_to_their_siblings/"]], "score": [18, 7]}}, {"q_id": "6pdhau", "category": "Repost", "title": "How do patents work? What can you patent? What can you not patent? How are patent infringements assessed?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkoi361"], "text": ["Yer not alone in askin', and kind strangers have explained: 1. [ELI5: How do patents work? ]( URL_3 ) 1. [ELI5 Patents? How do they work for simple things ? ]( URL_6 ) 1. [ELI5: How do patents work? ]( URL_2 ) 1. [ELI5: How patents work and could you re-apply after they expire? ]( URL_1 ) 1. [ELI5: How do patents work and what is involved with obtaining one? ]( URL_0 ) 1. [ELI5: How patents work ]( URL_7 ) 1. [ELI5: when you apply for a patent how do they check there isn't already a conflicting one? ]( URL_5 ) 1. [ELI5: Why do patents exist? ]( URL_4 )"], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/uvaxe/eli5_how_do_patents_work_and_what_is_involved/", "https://www.reddit.com/r/explainlikeimfive/comments/57al7j/eli5_how_patents_work_and_could_you_reapply_after/", "https://www.reddit.com/r/explainlikeimfive/comments/514ryy/eli5_how_do_patents_work/", "https://www.reddit.com/r/explainlikeimfive/comments/1zd0ia/eli5_how_do_patents_work/", "https://www.reddit.com/r/explainlikeimfive/comments/3q3lha/eli5_why_do_patents_exist/", "https://www.reddit.com/r/explainlikeimfive/comments/3e0i7c/eli5_when_you_apply_for_a_patent_how_do_they/", "https://www.reddit.com/r/explainlikeimfive/comments/5bh42e/eli5_patents_how_do_they_work_for_simple_things/", "https://www.reddit.com/r/explainlikeimfive/comments/22lcbv/eli5_how_patents_work/"]], "score": [3]}}, {"q_id": "6pdr5u", "category": "Repost", "title": "What happens to A bug when it's pushed out the window of a car and how can they fly around in your car?", "title_urls": {"url": []}, "selftext": "What makes the bug able the flu around the inside of your car while you're driving instead of being smashed to the back of the car? The bug obviously can't fly 60mph, so how can bugs fly around while you're driving? And what happens to them if you're going 60, and they fly out of the window?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkojza5", "dkok07o"], "text": ["The same reason you can walk through an airplane isle even though you are unable to move at hundreds of miles an hour (or fly). The same reason you are able to survive walking around outside even though the earth is spinning around at thousands of miles per hour. Ir more precisely, why you can swim in a pool even though that pool is spinning around the earth at thousands of miles an hour. The entire interior and the air of the car (or plane, or your place on earth) are all movin at the same speed. To the fly it makes no difference if the car is stopped or moving. It is sitting in a giant pool of air. All ot has to do is swim through that air.", "Do you get thrown back at 60mph when you are driving? I think that would be pretty distracting. The air inside your can is pretty stagnant, even with the windows open, and the only speed the fly has to care about is how fast it is going relative the air inside your car. When they fly out the window the are suddenly travelling 60 mph, and very quickly decelerate, though their inertia is small enough that they may actually be able to do so safely."], "text_urls": [[], []], "score": [12, 6]}}, {"q_id": "6pe997", "category": "Repost", "title": "How and why did the trend of inserting English phrases into Japanese songs start?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkonmyo"], "text": ["Yer not alone in askin', and kind strangers have explained: 1. [ELI5: Why do songs sung in foreign languages have lines in English? ]( URL_2 ) 1. [ELI5: Why do anime opening songs often include english words at key points in the song? ]( URL_3 ) 1. [ELI5: Why do the Japanese use so many English words and phrases in common speech? ]( URL_7 ) 1. [ELI5: Why in a lot of Japanese songs/sentences from shows, there are a lot of English words. ]( URL_0 ) 1. [ELI5: Why do a lot of Japanese song have some English words in 'em? ]( URL_4 ) 1. [ELI5, why do Soken and Nobuo compose songs with English Lyrics for a Japanese game? ]( URL_6 ) 1. [ELI5: Why Non-English Songs have English in them. (Korean, Japanese, ect.) ]( URL_1 ) 1. [Why do non English speakers sing in English? ]( URL_5 )"], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/1v73rr/eli5_why_in_a_lot_of_japanese_songssentences_from/", "https://www.reddit.com/r/explainlikeimfive/comments/35xgr1/eli5_why_nonenglish_songs_have_english_in_them/", "https://www.reddit.com/r/explainlikeimfive/comments/1xbbx1/eli5_why_do_songs_sung_in_foreign_languages_have/", "https://www.reddit.com/r/explainlikeimfive/comments/2xsnmd/eli5_why_do_anime_opening_songs_often_include/", "https://www.reddit.com/r/explainlikeimfive/comments/1bte91/eli5_why_do_a_lot_of_japanese_song_have_some/", "https://www.reddit.com/r/NoStupidQuestions/comments/6deye2/why_do_non_english_speakers_sing_in_english/", "https://www.reddit.com/r/ffxiv/comments/47n8q3/eli5_why_do_soken_and_nobuo_compose_songs_with/", "https://www.reddit.com/r/explainlikeimfive/comments/527v9l/eli5_why_do_the_japanese_use_so_many_english/"]], "score": [3]}}, {"q_id": "6pfhyf", "category": "Repost", "title": "Why does CGI on shows like Game of Thrones cost so much? What is the process of making a huge direwolf appear on screen?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkovwyy", "dkow9qo"], "text": ["It costs because you need a lot of skilled personnel doing lots of hours. Hiring and employing such people costs a lot of money, because they are rare and the project takes time.", "There's a scene in the latest GoT episode (no spoiler) in which someone jumps off a boat. Most of the boat did not exist, and neither did the sea around it and the sky above it: it was entirely CGI, and the acting was done in front of green screens in a parking lot in Belfast, with a few bits of wood to appear in close-ups. So that was expensive, but not nearly as expensive and time-consuming as it would have been to make a boat set, and the results are much better than if done the old Hollywood way with matte paintings for background."], "text_urls": [[], []], "score": [3, 3]}}, {"q_id": "6phz51", "category": "Repost", "title": "Why are galaxies planar and haven't been crushed into spheres by their own gravity, like other space objects of sufficient mass?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkpfvou", "dkpfsbo"], "text": ["Because they rotate. Angular momentum spins them into a disk orbiting the supermassive black holes in their center. It is the same reason solar systems do not all collapse into their star.", "Because they are spinning. Because a lot of this stuff had velocity not dirrectly in line with the center of gravity, it orbits instead of falling towards the center. A given chaotic mass, like a galaxy, will tend to average out the orbital velocities and form a mostly planar configuration as the various chaotic orbits interact with each other."], "text_urls": [[], []], "score": [5, 3]}}, {"q_id": "6pljb5", "category": "Repost", "title": "Why does the US have a President, but Canada and the UK have a Prime minister?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkq9y8p"], "text": ["The United States has a much stronger divide between the executive functions and the legislative function. When the Constitution was being written, the general goal was to create a government with a strong legislative center (Congress) and an executive that would help to balance Congress by holding the powers of execution (the President). Likewise, the President's king-like powers (leading the army, signing laws), could be limited by a distinct and powerful Congress with competing authorities (funding the army, writing the laws), and both could in turn be checked by a separate judiciary. Later on in the development of democracies and republics, people began to move more toward a parliamentary system. This is the case in England, where the King didn't get formally replaced, but slowly lost power to the legislature in bits and pieces over time. The checks and balances in such a system are weaker---since the head executive official is always the head of the legislature---but it also means that government is more efficient. In a parliamentary system, the parliament chooses the Prime Minister, who heads the government. Canada, gaining independence later than the U.S., also went with a system like the Parliamentary system in England, as did many of the other states that gained independence at the end of the colonial era in the mid-20th century."], "text_urls": [[]], "score": [4]}}, {"q_id": "6pmfve", "category": "Repost", "title": "What is consciousness?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkqhfal"], "text": ["Think of your body like a computer; an elegant machine. Now, one of the problems with computers is that you can't just throw the pieces together and have it process information, well... not on a complex level. So what is needed is an operating system. The unconscious, conscious and other bodily control factors are the operating system for your body. Why? Because your body has evolved to have one. For survival and reproduction, having a consciousness is vastly superior, as you can imagine. So why do you see through your eyes and not someone else's? Because your consciousness was shaped by your body. You wouldn't have turned into the same person you are today if you were inside the body of someone else. As a final thought, understand that we don't know exactly what consciousness is. We do have evidence that suggests it is just information, or the result or information. Studies suggest that the consciousness, or \"soul\" as some would call it, has no weight. This also leads us to believe that your consciousness is created by your body, and not the other way around."], "text_urls": [[]], "score": [3]}}, {"q_id": "6pmz76", "category": "Repost", "title": "Why does the prime minister of some countries appear to have more power than the president?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkqkm9u"], "text": ["Broadly speaking, there are three main systems of government around the world. There are Presidential systems where there is a president who is head of state and head of government (\"head of government\" being the person who makes most of the big decisions). There are Parliamentary systems where the head of state and head of government are separate. The head of government is a Prime Minister or equivalent, and the head of state is either a constitutional monarch or a president. The head of state typically has limited power (at least in practice, if not on paper), but is generally meant to make sure the government doesn't overreach its power. Then there are Semi-Presidential systems which is somewhere between, where both the President and Prime Minister share responsibilities for actually running the government. Singapore, Malaysia and India are all parliamentary countries, so it's their PM who sets their major policies. The USA is presidential, and France is semi-presidential. Of course there are some countries that don't follow any of these systems, and there can be a lot of variation within these categories, but most countries do fall into one of them."], "text_urls": [[]], "score": [5]}}, {"q_id": "6pnwub", "category": "Repost", "title": "Why are things so much more funny when you are not allowed to laugh?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkqw02z"], "text": ["That's an old question, if we make it broader. Similarly, why do sexual taboos arouse people so easily? Guys as old as Paul of Tarsus would talk about our inability to do what we want, and to not do what we don't. Freud would give complex explanations of psychological energies having a dynamic between the parts of the mind. Freud belive laughter was \"surplus\" mental energy relieved for some reason. For example, in jokes, we pay attention to the story, building up the energies of our \"inner censor\". When at the punchline it is revealed our internal censor did not need that much energy, the excess energy is relieved as laughter. He has different explanations for other kinds of comedy, too. Even if we don't accept 100% of Freud's conclusions, it makes sense that laughing is related to some for of \"energy\" that bursts out. And what is worse to build up energy, be it tension, anxiety, sexual arousal, then trying to to let it build up? It's like the \"don't think of a polar bear\" game. You always lose when you remember the game exists. The only way to not to think of a polar bear is forgetting about this prohibition. There's also the vicious cycle of trying to stay serious. You get prone to laugh, therefore more prone to perceive yourself in a silly state, therefore more prone to feel guilty and laught out of anxiety, therefore more prone to observe the absurd of a situation that should be serious and that you can't find serious anymore, which is natural comedy gold... An important part of this vicious cycle would be what Freud called \"economy of compassion\". Basically, it's the idea we don't laugh of things when we care - you don't laugh of a clown falling to the ground if you really think he got hurt (or maybe you do, if you hate clowns). And taking a dramatic situation and turning it non-serious is a classic comedic technique. When you start trying not to laugh of a serious situation, you get more and more emotionally distanced from it, which makes easier for it to become truly funny. If you like reading, this piece is simply *great*: URL_0"], "text_urls": [["https://plato.stanford.edu/entries/humor/"]], "score": [10]}}, {"q_id": "6pq568", "category": "Repost", "title": "If the primary colors are Red, Yellow, and Blue, then why are pixels made to only show Red, Blue, and Green?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkrambz", "dkrejn7", "dkrdwgk"], "text": ["RYB are the subtractive color primaries, which works with paints and reflective surfaces where adding more tends to make things darker. RGB are the additive color primaries, used on screens and projections, working with light sources where adding more tends to make things brighter.", "Primary colors as RYB (Red, Yellow, Blue) is mostly just for art, the scheme was created based on the way paint mixes. Unlike RGB (Red, Green, Blue) which is the basic or primary color scheme as defined for physics and chemistry texts and is used for electronics. RGB is also known as \"additive colors\" adding RGB together will produce a white light which is the basic principal behind TVs and other monitors. To get more into it RYB is for paint mixing and the like and RGB is for light. Because when you mix RGB light, mixing darker colors will produce lighter colors (i.e. mixing red and blue will produce a light pink). Where mixing paint darker colors give dark results (i.e. mixing red and blue will produce purple). So when it comes to colors the medium you're working with will decide what base color scheme is used.", "The difference is pigments (paints, ink, etc) are subtractive colors. Light is additive. Imagine this: mix together the primary colors of paint. You get a muddy brown. Mix together Red, Green, and Blue light (maybe with one [of thses]( URL_0 ) bad boys.) You get white light. Pigment primary colors are actually Cyan, Magenta, and Yellow (you may have a printer that takes CMYK ink cartridges, K is black.) Since the pigment is absorbing many frequencies (colors) of light and only reflecting a certain few, we call it subtractive. White light is made of many colors, and this can be seen in a rainbow or a [prism]( URL_1 ). Imagine you had a white sheet of paper with red text on it, and you only had a red light source. What would happen? The text would be invisible. Since the only color of light you have is red, only red can be reflected. If you add another color, then you will be able to see the red text, since the white paper will reflect both colors, while the red text will only reflect red."], "text_urls": [[], [], ["http://nothingbutnostalgia.com/wp-content/uploads/2015/12/Flashlight-PlaySkool.jpg", "https://ssl-static.libsyn.com/p/assets/b/a/4/9/ba495a92060ba1b6/prism.jpg"]], "score": [20, 4, 3]}}, {"q_id": "6pruiw", "category": "Repost", "title": "how is it that we live in the 21st century but still can't invent uncloggable toilets", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkrojbb", "dkroqfz"], "text": ["We can, but in the USA a law was passed some years ago that suddenly limited how much water a toilet can use to flush. Designers weren't ready, so for years they made ones that didn't work right. (Commercial buildings have higher water pressure, so theirs didn't do as badly.) Yer not alone in askin', and kind strangers have explained: 1. [ELI5: Why do American toilets clog up so much? ]( URL_4 ) 1. [ELI5: Why do American Toilets clogs up so easily? Is it the design fault? ]( URL_1 ) 1. [ELI5: What causes toilets to become clogged? ]( URL_5 ) 1. [ELI5: Why do american toilets clog so easily? ]( URL_2 ) 1. [ELI5: Why do the the toilets in public restrooms hardly ever clog? ]( URL_6 ) 1. [ELI5: Why does my toilet routinely clog on small-moderate sized shits, and handles massive sized one's with ease? ]( URL_3 ) 1. [ELI5: If public toilets are hard to clog, why don't we use the same technology for home toilets? ]( URL_0 )", "Outhouses and porta potties are uncloggable toilets. They exist. If you changed your home toilet to some other transport method (not using water and not using electricity), you could have one. It's mostly due to the shape of the toilet that is used so that we can have small amounts of water in use, and no reliance on electricity, merely pressure."], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/2x11dn/eli5_if_public_toilets_are_hard_to_clog_why_dont/", "https://www.reddit.com/r/explainlikeimfive/comments/3e5bdc/eli5_why_do_american_toilets_clogs_up_so_easily/", "https://www.reddit.com/r/explainlikeimfive/comments/2muyz4/eli5_why_do_american_toilets_clog_so_easily/", "https://www.reddit.com/r/explainlikeimfive/comments/2173wb/eli5_why_does_my_toilet_routinely_clog_on/", "https://www.reddit.com/r/explainlikeimfive/comments/2xlyz8/eli5_why_do_american_toilets_clog_up_so_much/", "https://www.reddit.com/r/explainlikeimfive/comments/19x6rd/eli5_what_causes_toilets_to_become_clogged/", "https://www.reddit.com/r/explainlikeimfive/comments/2k8xxf/eli5_why_do_the_the_toilets_in_public_restrooms/"], []], "score": [6, 3]}}, {"q_id": "6psbdz", "category": "Repost", "title": "Why does massaging sore muscles feel painful yet awesome at the same time?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkrsj0u"], "text": ["They found that massage reduced the production of compounds called cytokines, which play a critical role in inflammation. Massage also stimulated mitochondria, the tiny powerhouses inside cells that convert glucose into the energy essential for cell function and repair. \u201cThe bottom line is that there appears to be a suppression of pathways in inflammation and an increase in mitochondrial biogenesis,\u201d helping the muscle adapt to the demands of increased exercise, said the senior author, Dr. Mark A. Tarnopolsky. Dr. Tarnopolsky, a professor of pediatrics and medicine at McMaster University in Hamilton, Ontario, said that massage works quite differently from Nsaids and other anti-inflammatory drugs, which reduce inflammation and pain but may actually retard healing. Many people, for instance, pop an aspirin or Aleve at the first sign of muscle soreness. \u201cThere\u2019s some theoretical concern that there is a maladaptive response in the long run if you\u2019re constantly suppressing inflammation with drugs,\u201d he said. \u201cWith massage, you can have your cake and eat it too\u2014massage can suppress inflammation and actually enhance cell recovery.\u201d Source NyTimes"], "text_urls": [[]], "score": [3]}}, {"q_id": "6pt8o0", "category": "Repost", "title": "Why is internet (a direct connection) only fast enough to stream a few TV shows at once when digital TV antennas can receive hundreds simultaneously?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dks5h6k", "dks0ipo"], "text": ["Yer not alone in askin', and kind strangers have explained: 1. [ELI5: cable tv vs cable internet TV, what's the difference? ]( URL_0 ) 1. [ELI5: What is the difference between Cable TV and Cable Internet? Why doesn't TV ever need to stop and load like streaming services? ]( URL_1 ) 1. [ELI5: How can a television broadcast be seen by thousands of people, yet there is only one copy of it? ]( URL_3 ) 1. [ELI5: Why does cable work better than internet streaming services? ]( URL_2 )", "Just for terminology correction. The antenna does NOT receive and do anything with the channels it hears. IT just funnels the signal into a tuner. The tuner, which is on a set top box or integrated into your TV can generally only deal with processing and figuring out a single tv channel at a time, not hundreds. IT's like saying there is a hundred website on the internet you could potentially go to. However, your web browser has only one window, so you can only see one at a time. Thats how an antenna and tuner work."], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/17zjle/eli5_cable_tv_vs_cable_internet_tv_whats_the/", "https://www.reddit.com/r/explainlikeimfive/comments/2ys9q8/eli5_what_is_the_difference_between_cable_tv_and/", "https://www.reddit.com/r/explainlikeimfive/comments/5qr4av/eli5_why_does_cable_work_better_than_internet/", "https://www.reddit.com/r/explainlikeimfive/comments/45g4pv/eli5_how_can_a_television_broadcast_be_seen_by/"], []], "score": [3, 3]}}, {"q_id": "6ptdof", "category": "Repost", "title": "Why are different sized clothes all priced the same? e.g. A size 5 shoe costs the same as a size 13 shoe but they require vastly different amounts of material to make.", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dks5aur", "dks1qq5"], "text": ["Yer not alone in askin', and kind strangers have explained: 1. [ELI5: Why aren't plus size clothes more expensive than normal size clothes? ]( URL_1 ) 1. [ELI5: Why are different sizes of clothes the same price? Even though larger sizes would use more material than the smaller sizes. ]( URL_5 ) 1. [ELI5: Why are clothes of different sizes the same price? Are the price mark-ups from the manufacturer big enough to neglect the cost of the extra fabric in larger clothes? ]( URL_0 ) 1. [ELI5: Why do all sizes of clothes cost the same amount when there is significantly less material in a small than a XXXL? ]( URL_4 ) 1. [ELI5: How come shoes are the same price for different sizes? Don't bigger sizes shoe use more materials? ]( URL_2 ) 1. [ELI5: Why are bigger sizes of the same item of clothing the same price? ]( URL_3 ) 1. [ELI5: Why an XXL sized T-shirt would cost the same as a Small. ]( URL_6 )", "The actual cost of material is only a very small fraction of the cost of most clothing items. Most shoes cost practically nothing to make. A dollar or so of material sewn together by people making $0.25 an hour. The rest is shipping, marketing, and pure profit."], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/5al24j/eli5_why_are_clothes_of_different_sizes_the_same/", "https://www.reddit.com/r/explainlikeimfive/comments/2d9swd/eli5_why_arent_plus_size_clothes_more_expensive/", "https://www.reddit.com/r/explainlikeimfive/comments/5qxz0r/eli5_how_come_shoes_are_the_same_price_for/", "https://www.reddit.com/r/explainlikeimfive/comments/1qbo3v/eli5_why_are_bigger_sizes_of_the_same_item_of/", "https://www.reddit.com/r/explainlikeimfive/comments/1e4zzh/eli5_why_do_all_sizes_of_clothes_cost_the_same/", "https://www.reddit.com/r/explainlikeimfive/comments/2dfiyj/eli5_why_are_different_sizes_of_clothes_the_same/", "https://www.reddit.com/r/explainlikeimfive/comments/1vasuw/eli5_why_an_xxl_sized_tshirt_would_cost_the_same/"], []], "score": [7, 4]}}, {"q_id": "6ptmzf", "category": "Repost", "title": "How do cold chills work and why do they make people involuntarily spaz out for a second?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dks5rb6"], "text": ["Yer not alone in askin', and kind strangers have explained: 1. [ELI5: What causes us to get those random cold chills? ]( URL_3 ) 1. [ELI5: What are \"chills\" and why do we experience them? ]( URL_2 ) 1. [ELI5: Why do people get an involuntary shiver, or chill, at seemingly random moments? ]( URL_0 ) 1. [ELI5: Why do people get the shivers when there's a sudden significant temperature change? ]( URL_1 ) 1. [ELI5:What is happening when someone gets the shivers? ]( URL_5 ) 1. [ELI5: Why do we get \"chills\" when something extremely moving or pleasing happens? ]( URL_4 )"], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/1ltxyx/eli5_why_do_people_get_an_involuntary_shiver_or/", "https://www.reddit.com/r/explainlikeimfive/comments/3l3ty0/eli5_why_do_people_get_the_shivers_when_theres_a/", "https://www.reddit.com/r/explainlikeimfive/comments/27cwc0/eli5_what_are_chills_and_why_do_we_experience_them/", "https://www.reddit.com/r/explainlikeimfive/comments/2evxsp/eli5_what_causes_us_to_get_those_random_cold/", "https://www.reddit.com/r/explainlikeimfive/comments/394d8i/eli5_why_do_we_get_chills_when_something/", "https://www.reddit.com/r/explainlikeimfive/comments/2qu3rc/eli5what_is_happening_when_someone_gets_the/"]], "score": [3]}}, {"q_id": "6puyq1", "category": "Repost", "title": "Why do so many companies want you to download their app?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkscpda"], "text": ["It's a constant reminder of their existence and services, right on your screen, free advertisement."], "text_urls": [[]], "score": [5]}}, {"q_id": "6pv2n6", "category": "Repost", "title": "How does your body proportionately distribute fat/mass across your body? How does it evenly for the most part distribute to all parts of the body?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dksjmni", "dksg01n"], "text": ["Well for one thing it's not even and a lot of this has to due with hormone levels. Estrogen will generally signal for more fat storage in the legs, hence women having thicker legs and posteriors. Testosterone will favor the arms and upper body. Cortisol will favor the stomach. See people with Cushing's for extreme example. Insulin the sides of the stomach. (love handles).", "You have specialised adipose tissue throughout the body which converts excess food to fat and stores it. The more excess the more it divides and grows, where the fat is stored is based on age/sex/genetics as well as where the tissue is."], "text_urls": [[], []], "score": [11, 3]}}, {"q_id": "6pv4nh", "category": "Repost", "title": "NSFW: Why is a sweaty ball scratch so enjoyable and do females have an equivalent place they love to scratch?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dksdvgb"], "text": ["I've been told general down there scratching feels nice to everyone because of the intense amount of nerve endings present in similar tissue type. Or how it was put to me: \"nah. Vagina scratching feels good as hell\""], "text_urls": [[]], "score": [6]}}, {"q_id": "6pw5jy", "category": "Repost", "title": "Why does the pigment in animals eyes change colour only after birth ? Are there any other body parts that change in a dramatic way?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dksoofp"], "text": ["Hum, if I remember correctly, the pigment never change colour. What happens is that the \"default\" color is blue for quite a lot of mammals. After birth, the eyes begin to produce a pigment called melanine that gives the eyes their definitive colour."], "text_urls": [[]], "score": [3]}}, {"q_id": "6pz5kg", "category": "Repost", "title": "Why are under cooked burger patties are safe to eat?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dktavvw", "dktb6my", "dktb7sg", "dktax61", "dktb871"], "text": ["It's basically... not. Everyone eating a medium rare patty that's not recently fresh ground from a whole steak is risking food poisoning. You just luck out more often than not due to meat processing factories keeping to pretty strict cleaning routines.", "Um. Kinda, but not quite. The bacterias that typically gives us problems with undercooked meat: e-coli, lysteria in beef, trichonosis in pork - these bacteria are commonly found in the environment of those animals, on their skin, feces etc., digestive organs. Proper slaughter, handling and butchering of the animals trys to keep all of that stuff separate from the actual meat flesh. Cases where bacteria are introduced to say ground beef, usually this is due to improper cleaning of the processing equipment or poor staff practice, or simply cutting corners. Or, in the case of those few trichonosis cases from wild boars and such, its because of poor butchering practices - people not knowing what they're doing. If you have properly slaughtered animal meat, in a clean and modern, regularly inspected facility, you should be able to eat it raw (in theory). The cook to internal temperature guidelines are simply good practice for \"just in case\"... because food poisoning through bacterial infection is NOT fun. Note: This applies to beef and pork. Im pretty sure you'll still want to cook your chicken though. The vectors for bacterial infection are the same... and if you _really_ trust your butcher, go for that chicken sashimi.... its just harder to keep chicken flesh clean when you butcher it due to the small size of the animal.", "They are not safe to eat. If they were ground very recently (in the last hour) the danger is less. If they were ground yesterday, or left out in a warm environment, really not recommended.", "They aren't necessarily undercooked. They are just pink. You can fully cook and pasteurize meat at fairly low temperatures. With sous vide you can fully cook and pasteurize at 130 degrees, and the burger is still very much pink.", "It's not safe. We take a calculated risk when we eat undercooked burgers. You have to cook a burger to a higher temperature than steak in order for it to be safe. URL_0"], "text_urls": [[], [], [], [], ["https://www.foodsafety.gov/keep/charts/mintemp.html"]], "score": [6, 6, 5, 4, 3]}}, {"q_id": "6q18cr", "category": "Repost", "title": "What exactly is plasma?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dktywjk"], "text": ["Imagine an atom. The electron and neutron are seperate entities of the same thing. Now imagine that the electron doesn't have to hang out by its neutron & proton buddies (Nucleus) but can swim around freely with the rest of its plasma buds. Give enough energy to a gas and it will seperate into its different parts. Everything is in the same 'container' though. Kinda like this drink URL_0 All of the pieces are there just 'seperated' Edit: Corrected Neutron into Nucleus"], "text_urls": [["https://mixthatdrink.com/wp-content/uploads/2011/04/layered-cocktail-tutorial-cloudy-600x600.jpg"]], "score": [9]}}, {"q_id": "6q1s9t", "category": "Repost", "title": "laundering money", "title_urls": {"url": []}, "selftext": "So I'm watching this new show on Netflix ozark and the main character in the show is laundering money for a drug dealer and hes cleaning the money by investing in businesses and buying alot of things for those buisnesses. How does this exactly clean the money? And how do they get that money back?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dku2qyq", "dktwrb7", "dktwywm", "dkuexqq", "dktwnrc", "dktwnrr", "dkue1yg", "dktwjqu", "dktxfyl", "dku66d6", "dktx2ga", "dku5hrj", "dkv0o9w"], "text": ["One day you start taking your dad's porn magazines to school, you sell them at like 2 dollars a pop. Your dad is an avid collector with a boxes full of them stashed away, so he's not noticing that you're taking them. You've started to save a fair bit of money from this so you decide you want to buy a new bike with the money. But you realized something, won't your parents wonder where you got the money? You can't tell them what you are really doing cause you'll get in trouble. You aren't doing any work or making money from chores or anything and suddenly you've got enough money for a bike? You need to show them that you're a good boy and earned your money fair and square. You get an idea that you'll start mowing some lawns for pocket money. You ask your parents if you can use the mower and they say yes. Now mowing lawns is hard work so you decide to fake it a little bit. You mow 1 lawn a day but say you did 3. You're only getting 10 bucks for the 1 lawn so you make up for the other 2 with your porn magazine money. Over a few weeks you've moved all your bad money through the lawn mowing business. You can now buy your bike because you earned it by being a good boy and your parents are so proud.", "a) as /u/cerberus698 has explained there's laundering as in just getting \"clean\" money that (each note has a individual ID, the bank you robbed might know the IDs of the stolen bills). b) more importantly, and difficult, is getting money to appear legitimate. If you rob 1 million dollars from a bank I just need to look for someone who suddenly has a million dollars for no particular reason and I have a suspect. Or, perhaps more effectively, I could look at people who are making lots of money while poorly or unemployed to find drug dealers and other blackmarket operators. So all those people need a legal \"front\" from which they \"earn\" the money they've earned illegally. For example, in Breaking Bad the family launders money via a car wash company. The car wash company might see x clients in a day. But you fake the books and say you saw x + y clients in a day, y being fake clients and you put your money from drug dealing/etc in the till equal to the amount they would have paid. Now given the car wash might break even or make a small loss from its actual clients, this extra money will filter through the business and end up as extra profit which you can pay taxes on and spend without it being obvious you have an extra source of income. Of course this only works to an extent, if you're laundering loads of money through the car wash it becomes conspicuous. Someone might notice how ridiculously profitable your business is, and then investigate and find you're not seeing enough customers to make as much money. Thus the need to ever expand money laundering operations.", "Let's use a simple example. You have a lot of illegally earned money. I have a legitimate business that sells pizzas. You buy a portion of the business (with legal cash), as the owner of the business you are entitled to a share of the profits. You then make a order for 500 pizzas, and pay for it with your illegal cash. The store will make some money from the sale of those pizzas, more if they never actually make/deliver the pizza, just ring up the sale for it. At the end of the year, the store will show a great deal of profit from the sale of the ghost pizzas. The store will then pass those profits back to the owner as a dividend. So on paper, it looks like the business is highly profitable, and you have earned a great deal of money as dividend from that business. Another way is two people to play poker at a las vegas casino. One person will intentionally keep losing to the other person. So the \"winner\" will just have to declare legitimate casino winnings as their income. Minus of course whatever fees the casino charges to run a private poker game.", "First, Marty explained to the Langmores why the $8 million was almost useless to them. Ruth driving a Ferrari around the lake or Russ building a 5,000 sq. ft. house on the lake would draw immediate suspicion. In order to be able to actually spend the money, they need some way to make it look legitimate. What Marty does is take all the drug money and invest it into legitimate business. Then he can \"cook the books\" (fake the accounting) to make the businesses appear more profitable than they are. Now he can deposit the drug money in the business account and pay the owners hefty salaries so they receive a legitimate paycheck. This also helps avoid the Al Capone situation, where the Feds knew what he was doing, but couldn't pin anything on him. They eventually got him on tax evasion. I assume the show isn't going to go into a lot of detail for the same reason Breaking Bad didn't show the exact recipe for making meth. They want it to be a drama, not a tutorial. As long as you understand that Marty is taking illegally gained money and channeling it through legitimate operations to make everything look on the up and up, that's all we really need to know to enjoy the show. Hope that helps.", "The definition of laundering money is to conceal the source of income. If you have large sums of money without any way to account for it, the feds are on your ass faster than trailer trash on velveeta, hence dirty money. To clean the money you need a shell business to have a source of documented income so you can actually use all of that money without being on anyone's radar and utilize a bank account. You keep the money but it has to look legit, like clean money.", "Imagine you have a large cash \"business\" i.e. selling drugs. You start getting a lot of cash and you want to spend it. The problem is, for larger purchases (houses, cars, etc) you need to have clean money. If you go to a bank and hand them $10,000 in cash the IRS is going to look into it because that money was not reported or taxed. So large scale criminal enterprises need to clean their money. They do this by finding a business that uses a lot of cash (in Breaking Bad they use a nail salon). They give cash to that business, the business reports it as income from imaginary customers, pays taxes on it, and the criminal organization takes what's left after taxes and however much the semi-legit business takes. Now they have the money in a bank account, it's been taxed, and they can use it for whatever they want.", "Three basic steps to laundering: Placement: Getting the money into the financial system. This step is why financial institutions report cash transactions $3k and up to the government/regulators. Layering: After money is in the financial system it gets moved around in numerous transactions. This is to hide the origin and make it more difficult to trace back. Integration: Pulling the now seemingly legit money back out so the criminal can use it. Source: I work for a financial institution and have to take yearly training on this.", "There is a simple way to launder small amounts of cash. Say you have 1000 dollars in bills robbed from a bank or maybe even just in counterfeit currency. It's not safe to keep them but you need to stash the cash. You could go to convenience stores with the 20 dollar bills and buy 1 dollar packs of gum and get 19 dollars in change. You've just exchanged your 20 dirty dollars for 19 clean ones and can now safely hold onto it. At the end of the process you will have less than what you started with but all of it will be clean and entirely untraceable to your crime.", "Laundering the money through a legitimate business under the facade that it was used for an actual business expense provides a fake source of expenditures. The money is reported to the IRS as a business expense and they offset this with a fake revenue amount so the IRS isn't out any tax dollars. Essentially it allows the launderer (first time I've used that word) to pay tax on the money and not arise suspicion in the eyes of the government. If the IRS was to audit the expenses or revenues of the business they would likely provide forged receipts that reflect the dollar amounts. That is the main risk, in that they could then tie the receipt to whomever issued it - to ostensibly double audit it. Unlikely they would do this. The other risk is having a 'story' that makes no sense, like that shitty clothing store down the street that sells only Jamaican-themed clothing but operates at the most expensive downtown location. Overall, it allows criminals to do things like obtain mortgages and be like the rest of us.", "You have money that you have gained by shady means. Maybe it's drug money, maybe it's bribes, whatever. You can't put this in your account without getting suspicious looks from the government. You can spend it on stuff you can pay for in cash, but at one point you run up against a wall with that. You need this stuff in a bank. So you create a business, and that business is a money laundry. The name comes from the fact that laundries often were one of the favorite businesses for this. You need something in which people pay with cash a lot. So you put up this business, and do all those small bits which make it look like, at least on paper, to be a real working business. You don't really need customers for that, you just need the possibility that there are customers. Instead of the money from actual customers you use the dirty money for that, and you put it on the books as income. You pay taxes on it and it becomes \"clean\". There's lots of different ways to do that. Laundries are a perennial favorite, restaurants and bars also work well. I know one pizza stand which is completely out of the way and has never had a single customer anyone has seen, and which still is there 15 years later.", "Money laundering is when you exchange illegally acquired money for legal money. Illegal money would be something that can be traces back to some sort of crime, like sequential bank notes. One method people use is to exchange this illegal, or \"dirty\" money, by using it to buy legitimate goods (like art work), then sell the goods to gain legal or \"clean\" money. It's called \"laundering\" because you are cleaning dirty money. Other methods include creating an \"alibi\" for the money you acquired. The alibi switches the source of the money from the crime committed (like drug deal) to a legitimate business deal (like selling products and services). This method is slower and more reliable, because you can report inflated sales numbers at a controlled rate (let's say, $1000 per day is reported in sales, but it really mostly comes from your own pocket) without raising suspicion. The best example of money laundering is in Rush Hour 2. The main villain makes $50 million dollars in counterfeit bills. He uses this to run a casino that was legitimately purchased by a wealthy investor. The casino gains money from people buying chips with legitimate money to play games. When players want to cash out their chips at the end of the day, they receive the counterfeit money instead of the legitimate money that the casino acquired through chip sales.", "Minor Spoilers: I feel Ozark doesn't try to show a realistic way to launder money. For it to work, the main character needs to find a business or businesses which can report additional 8 million in exchange for some percent of the money. However none of the businesses he joins or buys can handle that much money within a short time span. IRS would probably flag them when they file taxes. I think he's actually doing slightly different thing and might have a partner, because they say he buys a lot of air conditioners for one of his businesses yet they get only one unit, it's possible the store selling air conditioners is one of the fronts for money laundering. The act of buying doesn't really help unless the business getting the money is a part of the conspiracy.", "The car wash from Breaking Bad taught me a lot about money laundering. To make illegally obtained money \"clean\", you just slip it into the revenue stream of a seemingly legitimate business through fake sales and services. Not too much. But just enough that it looks like you are turning a decent profit. Then it is possible to inflate your expenses a little more in order to compensate for the windfall. Then you can slip a little more dirty money in and repeat. Or you can expand into other \"cleaning\" services. Having large sum of inexplicable money just appearing or disappearing tips off the feds big time."], "text_urls": [[], [], [], [], [], [], [], [], [], [], [], [], []], "score": [1402, 419, 90, 77, 18, 12, 8, 7, 7, 7, 6, 5, 3]}}, {"q_id": "6q2ihp", "category": "Repost", "title": "Water boils at 100\u00b0C. How come steam comes off of water before it hits 100\u00b0C?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dku1ksk"], "text": ["There are two different phenomena. One is the change of state: from liquid to gas (water to water vapour). Given a pressure and temperature, water exists in one form or another. If you had an isolated system with liquid water in it, kept pressure at 1 atm and start raising the temperature, at 100\u00b0 it will all turn to gas. But that's not what you have. Your system is not isolated. You have an *air-water interface that is not in equilibrium*. This is related to something called \"water vapour pressure\". Water vapour can very well exist at room temperature (thank god, or you'll be breathing dry air, very uncomfortable). Water molecules will be released from the water surface and evaporated until the ambient humidity reaches equilibrium (100%). Thank god again, or you'll never get your clothes dry when hanging them in to dry. At that point (100% humidity), no more water will evaporate from the pot. Better said, water will keep evaporating and condensating back so that the relative humidity stays 100% and apparently everything is stable. If you happen to have 120% relative humidity you're out of the equilibrium again and the water in the air will condensate until equilibrium is reached (100% relative humidity). When you are heating water in a pot, it gets hot (duh!) and it's easier for the molecules to jump out and join the air (and evaporate and become water vapour, which is invisible to humans, by the way, that \"smoke\" you see over the pot is still tiny water drops). But the reason behind it is that the air needs them to reach equilibrium (100% humidity), not that the water is changing state earlier than expected."], "text_urls": [[]], "score": [4]}}, {"q_id": "6q3zlo", "category": "Repost", "title": "Why do our bodies generally tend to want to eat unhealthy food more than healthy food even if it\u2019s worse for us?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkubrh6"], "text": ["For the longest part of human history the struggle was to get enough calories to survive. Evolution molded our diets to prefer calorie-dense foods because anyone who desired leaves over meat would have died of starvation and not passed their genes on to the next generation. However, in only the past few tens of thousands of years, we now produce more calories than we consume. That may sound like a long time but it's not nearly long enough for it to have had a large impact on our instinctual desire for certain foods. Our instincts still tell us that we might starve if we don't get enough calories and so we desire unhealthy foods."], "text_urls": [[]], "score": [3]}}, {"q_id": "6q5mcy", "category": "Repost", "title": "What the hell is 'fake news' and why should we care?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkupny6", "dkupq80"], "text": ["Before Trump \"Fake News\" was news that was intentionally false, or intentionally highly misleading with components of truth presented in a false manner. Its intent is to deceive the public, much like propaganda, but without the government control elements that propaganda has. But with Trump it is any news that he does not like. Anything that goes against his personal narrative, regardless of if it is truthful or not.", "The term was originally meant to be for click-bait pages that appear to be giving legitimate news but is in fact just trolling for hits and total baloney. Now, T-dog uses it for all sorts of news. He applies it to CNN when their coverage focuses on things he's rather they not focus on. He applies it to news from trusted-but-unnamed sources. He applies it just to jab at liberal news in general."], "text_urls": [[], []], "score": [5, 3]}}, {"q_id": "6q6k7y", "category": "Repost", "title": "If heat rises, why are mountaintops full of snow?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkuxi4d", "dkuxiyj"], "text": ["Yer not alone in askin', and kind strangers have explained: 1. [ELI5: Heat rises, yet it is cold on top of a mountain. E ]( URL_3 ) 1. [ELI5: If heat rises, why is it freezing cold above the clouds? ]( URL_5 ) 1. [ELI5: If heat rises, why are higher altitudes generally colder? ]( URL_2 ) 1. [ELI5: If heat rises, why is it so cold in the mountains? ]( URL_6 ) 1. [ELI5: If heat rises, why is it cooler in the mountains than the valley. ]( URL_1 ) 1. [ELI5: If heat rises, why are mountain summits so cold? ]( URL_0 ) 1. [ELI5: if warm air rises, why is it colder the farther you get from the earth's surface? ]( URL_4 )", "As you go upward in the atmosphere, the air gets less dense, so it can't hold onto heat like the more dense air at sea level. Hot air rises because the molecules are moving around more, making them less dense. Then like air bubbles in water, they rise to the top where they sit in the less dense air, and are unable to hold their energy."], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/6f9mnz/eli5_if_heat_rises_why_are_mountain_summits_so/", "https://www.reddit.com/r/explainlikeimfive/comments/6m5qqn/eli5_if_heat_rises_why_is_it_cooler_in_the/", "https://www.reddit.com/r/explainlikeimfive/comments/11gp42/eli5_if_heat_rises_why_are_higher_altitudes/", "https://www.reddit.com/r/explainlikeimfive/comments/m7k2s/eli5_heat_rises_yet_it_is_cold_on_top_of_a/", "https://www.reddit.com/r/explainlikeimfive/comments/2fj5pn/eli5_if_warm_air_rises_why_is_it_colder_the/", "https://www.reddit.com/r/explainlikeimfive/comments/406dh7/eli5_if_heat_rises_why_is_it_freezing_cold_above/", "https://www.reddit.com/r/explainlikeimfive/comments/36jhn3/eli5_if_heat_rises_why_is_it_so_cold_in_the/"], []], "score": [9, 3]}}, {"q_id": "6q796d", "category": "Repost", "title": "Why is the former town of Chernobyl still uninhabitable yet Hiroshima and Nagasaki are thriving cities?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkv3dqy", "dkv3ymg"], "text": ["nuclear bombs and nuclear reactors are pretty different beasties, despite both relying on nuclear material to do their thing. In the atomic bomb blast, almost all of the nuclear material was destroyed at the atomic level, releasing a tremendous amount of energy. It resulted in only trace amounts of radioactive material actually being left over. In the case of the chernobyl disaster, the leak meant the material didn't explode or evaporate, it just stayed put, being radioactive.", "Yer not alone in askin', and kind strangers have explained: 1. [ELI5: Why can people live in Hiroshima and Nagasaki, where a bomb spread radioactive material, but people are unable to safely survive for long periods of time in places such as Chernobyl or Fukushima? ]( URL_3 ) 1. [ELI5:How can Nagasaki and Hiroshima be habitable after WW2, but Chernobyl won't be habitable for at least 600 years? ]( URL_0 ) 1. [ELI5: Why are Hiroshima and Nagasaki both inhabitable but not Chernobyl? ]( URL_5 ) 1. [ELI5: Why The nuclear accident in Chernobyl left the city indefinitely uninhabitable while cities like Fukushima, Nagasaki, and Hiroshima are populated (to my knowledge) ]( URL_1 ) 1. [ELI5: Why can people live in Nagasaki and Hiroshima but not in Chernobyl? ]( URL_2 ) 1. [ELI5:Why can people live in Hiroshima & Nagasaki but not in Chernobyl? ]( URL_4 )"], "text_urls": [[], ["https://www.reddit.com/r/explainlikeimfive/comments/390d2u/eli5how_can_nagasaki_and_hiroshima_be_habitable/", "https://www.reddit.com/r/explainlikeimfive/comments/6hj2wk/eli5_why_the_nuclear_accident_in_chernobyl_left/", "https://www.reddit.com/r/explainlikeimfive/comments/65y1t7/eli5_why_can_people_live_in_nagasaki_and/", "https://www.reddit.com/r/explainlikeimfive/comments/1lq2e8/eli5_why_can_people_live_in_hiroshima_and/", "https://www.reddit.com/r/explainlikeimfive/comments/2ciq1p/eli5why_can_people_live_in_hiroshima_nagasaki_but/", "https://www.reddit.com/r/explainlikeimfive/comments/40gdq0/eli5_why_are_hiroshima_and_nagasaki_both/"]], "score": [11, 3]}}, {"q_id": "6q7fxe", "category": "Repost", "title": "How does the IQ test accurately measure intelligence?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkv56eb"], "text": ["It does not. It was proven, almost as soon as it was invented, that not only were the areas the IQ test was used for like spacial reasoning, and pattern recognition were completely arbitrary, it was found that it neglected to test much more abstract, much more important aspects of intelligence like social intelligence, physical intelligence, mathematical, literary, good old fashioned common sense, and many, many other types of intellegences. I'm addition intelligence itself is completely arbitrary. As the old saying goes if you judge a fish by its ability to climb trees it will always be stupid. These realizations, in addition to the fact that minorities tended to score low on these tests due to their Reliance on more practical intelligences due to their harsh role in society, compared to the abstract types comprising the test it was used to \"prove\" that whites were the superior race, a fact that the well meaning inventor of the test regretted to his dying day."], "text_urls": [[]], "score": [6]}}, {"q_id": "6q7k6p", "category": "Repost", "title": "What is depression?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkv5sj3", "dkv7btl"], "text": ["At its' core, what we know about depression is that it can have many different \"causes\", but the symptom that causes the most problems are dulled or non-existent serotonin and dopamine receptors. This is a problem, because serotonin and dopamine are the chemicals that allow us to feel happy in the first place. So, that is why it's so hard to get out of: A depressed person's brain is physically unable, whether temporarily or physically, to feel happiness for whatever reason. This doesn't mean that you're always *sad*, but it *does* mean that all that you *can* feel are pretty negative emotions. It's definitely something that can be overcome, but it's seldom something that can be just \"gotten over\" I don't like just linking to videos, but [this lecture on depression from Stanford]( URL_0 ) covers so much of it that I implore you to watch it when you have the free time. The summary of the thesis, as taken from the video's summary, that \"depression is as real of a biological disease as is diabetes.\"", "**Clinical depression** is a mental disorder that causes distorted thinking, decreased emotional affect, changes in eating and sleeping habits, and some other significant symptoms. Let's imagine that you lose your job, your dog gets hit by a car, and your romantic partner leaves you. Feeling awful would be a normal, healthy response. Now let's imagine you get a promotion at your job. You spend an afternoon with your dog at the dog park, before coming home to your romantic partner who takes you out on a lovely date. Feeling awful *then* would seem abnormal, wouldn't it? One major feature of clinical depression is a lowered range of responses. After a great day spent doing a favored hobby with friends, a person with clinical depression would feel *neutral* or numb, or \"OK\". Not happy, not relaxed, not euphoric, just not-awful. The entire range of emotion from \"happy\" to \"unhappy\" gets slid down from \"really terrible\" to \"not-soul-crushingly-awful-this-minute\". Feeling awful is, well, awful. Feeling awful when there's no obvious cause adds an additional level of distress, because our minds like things to make sense. People with clinical depression sometimes do strange things to make their lives worse, because on some level, that helps the feelings they're experiencing \"make sense\". Feeling awful is some thing people try to avoid. When people are hurting, they may try to make themselves feel better. One way some people use is self-medicating, using known chemical responses to things like sugar or caffeine or alcohol or other substances to trigger feelings of pleasure, to alleviate the pain they're feeling. Self-medication is dangerous, because there's no objective check on how often, or how much you do, and because some chemicals create short-term ups, but contribute to longer-term downs. Cognitive distortions (thinking in ways that aren't really based on reality) in depression tend to be self-reinforcing. A person who believes they are awful will interpret events to make themselves feel worse. > Why is it so hard for some people to get out of it? Some theories suggest there's a chemical or biological component, the way two people can eat the same diet and do the same exercise, but one person loses a lot of weight and the other person doesn't. Because some elements of the disorder are rooted in cognition, it can be difficult to learn new ways of structuring our thinking. Imagine learning how to write with your non-dominant hand. Yes, you can do that, but it's difficult, takes practice, and effort. And because the disorder features feelings of powerlessness, helplessness, and fatigue, that makes the effort much harder to make. It's a complex disorder that we're still learning about, but for many people, a treatment that includes exercise, talk therapy of some sort, and medication for support seems to alleviate the worst symptoms and can restore a lot of function during an episode."], "text_urls": [["https://www.youtube.com/watch?v=NOAgplgTxfc"], []], "score": [3, 3]}}, {"q_id": "6q8knh", "category": "Repost", "title": "why do people say \"bless you\" when someone sneezes?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkve2d1"], "text": ["In Medieval times it was believed that when you sneezed your soul escaped out your body. If you were not careful the Devil could come and snatch it away so you said \"bless you\" to ward off the Devil and protect your soul."], "text_urls": [[]], "score": [4]}}, {"q_id": "6q8wyl", "category": "Repost", "title": "Why do people and companies blur out license plates? Couldn't I just go outside and get someone's plate number if I needed it?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkvk3h9", "dkvizu1"], "text": ["Yer not alone in askin', and kind strangers have explained: 1. [ELI5: Why do some people blur out/black out license plate numbers in pics of vehicles? ]( URL_1 ) 1. [ELI5: Why do people blur out their license plate in pictures? ]( URL_2 ) 1. [ELI5: Why does Google Maps blur out license plates when you can go outside and look at license plates all day? ]( URL_3 ) 1. [ELI5: Why do people often blur out license plates if they're considered public info? ]( URL_5 ) 1. [ELI5:Why do they blur out license plates on TV? ]( URL_0 ) 1. [ELI5: Why do people blur/blackout license plates when posting vehicle pictures online? When I can obviously see everybody's license plate while out in public. ]( URL_4 ) 1. [ELI5:Why do people blur out their license plates in pictures? ]( URL_6 )", "After looking this up online, it sounds like there is no single reason and there are no laws requiring people to do so. Here are some reasons that make sense though. * Some movies/tv shows require consent from everyone to be filmed. If they blur out any identifying information on someone in the background like a license plate, someone can't come up to them later and say the producers didn't get their consent to film their car and use it to make money. * Privacy. If someone's parked out in front of a strip club, yeah people may see their car, but no one would think anything of it. Now if the Google Maps car comes driving by and takes a photo of it without blurring the license plate, now there's forever a record of that person being at the club. * People are weird. Think of a movie where the characters drive around in a car a lot. Not anything unique like the bat mobile. Just a regular car. Now if some crazy super fan were able to see the license plate in the movie, they'd be able to find information about the exact car in the movie, who owns it, etc. (In some countries you can get more information from a plate number than others). Similarly, maybe that crazy super fan is watching their favorite TV show and sees 5 license plate numbers in the background of a neighborhood. The fan finds the addresses of the owners of the cars and finds out that 4 of them live in the same neighborhood. There's probably a good chance that the show is filmed in that neighborhood. I've heard the house that Breaking Bad was filmed in has a problem of fans coming to it ever though it's just some random woman's home now, and I'm sure it's happened to other shows as well. Blurring out the license plates just makes things like this harder to track down. * Some sources that I came across said the number could be used for fraud, and that's why it's often blurred. Personally I don't really buy that one since you'd have the same amount of information (plate number, car make, car color, location, etc) as any other car that you see on the street."], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/4208jm/eli5why_do_they_blur_out_license_plates_on_tv/", "https://www.reddit.com/r/explainlikeimfive/comments/6iav3c/eli5_why_do_some_people_blur_outblack_out_license/", "https://www.reddit.com/r/explainlikeimfive/comments/5nxsdv/eli5_why_do_people_blur_out_their_license_plate/", "https://www.reddit.com/r/explainlikeimfive/comments/3444s4/eli5_why_does_google_maps_blur_out_license_plates/", "https://www.reddit.com/r/explainlikeimfive/comments/25j13l/eli5_why_do_people_blurblackout_license_plates/", "https://www.reddit.com/r/explainlikeimfive/comments/1pllo4/eli5_why_do_people_often_blur_out_license_plates/", "https://www.reddit.com/r/explainlikeimfive/comments/2zi662/eli5why_do_people_blur_out_their_license_plates/"], []], "score": [5, 3]}}, {"q_id": "6q99re", "category": "Repost", "title": "Why do the next year's model of cars come out so early in the year before it? (2018 cars coming out in the middle of 2017)", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkvkydi"], "text": ["Yer not alone in askin', and kind strangers have explained: 1. [ELI5:Why do new cars that are actually made in one year sold as the upcoming year model? ]( URL_4 ) 1. [ELI5: Why are car models always a year ahead of what they actually are? ]( URL_2 ) 1. [ELI5: Why do car manufacturers title their car models a year ahead of the current year? ]( URL_6 ) 1. [Why are car models always a year ahead? ]( URL_1 ) 1. [ELI5: How can be a car declared as a car of the year, in the middle of the same year? ]( URL_0 ) 1. [Why are cars sold before the actual year of their model? ]( URL_3 ) 1. [ELI5: Why does the year of vehicle models correspond to the year after they were originally released? ]( URL_5 )"], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/2ih33j/eli5_how_can_be_a_car_declared_as_a_car_of_the/", "https://www.reddit.com/r/NoStupidQuestions/comments/5knljv/why_are_car_models_always_a_year_ahead/", "https://www.reddit.com/r/explainlikeimfive/comments/29wle1/eli5_why_are_car_models_always_a_year_ahead_of/", "https://www.reddit.com/r/NoStupidQuestions/comments/4seomo/why_are_cars_sold_before_the_actual_year_of_their/", "https://www.reddit.com/r/explainlikeimfive/comments/1wx7t1/eli5why_do_new_cars_that_are_actually_made_in_one/", "https://www.reddit.com/r/explainlikeimfive/comments/1d53az/eli5_why_does_the_year_of_vehicle_models/", "https://www.reddit.com/r/explainlikeimfive/comments/1m2rni/eli5_why_do_car_manufacturers_title_their_car/"]], "score": [3]}}, {"q_id": "6qbqp6", "category": "Repost", "title": "Why certain medications can create suicidal thoughts in people's minds?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkw2hjc"], "text": ["Medications don't 'create specific thoughts', they influence the balance of neurotransmitters in your brain. The mood you feel is a product of the specific and relative balance of these mood-determining chemicals. As usual, both too much *and* too little of something lead to what we consider negative effects. Consider serotonin; it is one of the neurotransmitters that regulate 'happiness'. I say happiness, but it's more like 'activity'. Low levels of serotonin are associated with low mood, lethargy, and depression. It's not that a drug that lowers your serotonin level implants the 'suicide' thought, it's that the suicide thought is a common reaction to feeling depressed in the way that stubbing your toe on a table is associated with saying 'ow'. The table doesn't put the word ow into your mouth. Antidepressants like SSRIs often inhibit the breakdown of serotonin in the brain to try to keep the levels above where you get depressed. Too much of it, though, is associated with anxiety and a kind of cellular hyperactivity which can be harmful and even lethal at very high levels, so it's not like we can just take drugs to super-boost our serotonin levels. And serotonin isnt just a standalone mood lever from 'low' to 'high', it's one of a network of interracting chemicals, the total product of which is our mood and thereby our thoughts associated with particular emotions or states. A drug that down-regulates one could up-regulate another, so it's often a balancing act. Fun fact: most of the body's serotonin is actually found in the intestinal tract where it helps regulate the pumping action of the guts moving waste. High levels of serotonin in the gut lead to diarrhea. This may be why some people have bowel issues when they get stressed - serotonin gives you both anxiety and the runs when it's high. Tl;dr: brain drugs are a complex network that control our moods, and certain combinations lead to depressed moods to which suicidal thoughts come more readily, but they don't create specifically suicidal thoughts. Also, poop. Source: I poop when I'm stressed. Also, an education in biochemistry or whatever."], "text_urls": [[]], "score": [4]}}, {"q_id": "6qc4qf", "category": "Repost", "title": "Locked smartphones.", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkw5lk2"], "text": ["Yer not alone in askin', and kind strangers have explained: 1. [ELI5: How come you cannot carrier unlock a mobile phone without paying for a \"code\", even with custom firmware and root access? ]( URL_1 ) 1. [ELI5: What exactly is \"unlocking\" a phone? Why is it a big deal in the news in the past month? ]( URL_4 ) 1. [ELI5: What is meant by an \"unlocked\" phone? ]( URL_0 ) 1. [ELI5: Unlocked Smart Phones ]( URL_2 ) 1. [ELI5: Cell phones \"locked\" to carriers, and unlocked phones ]( URL_3 ) 1. [ELI5: how does cell phone unlocking work? ]( URL_5 )"], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/3fm9om/eli5_what_is_meant_by_an_unlocked_phone/", "https://www.reddit.com/r/explainlikeimfive/comments/48ypex/eli5_how_come_you_cannot_carrier_unlock_a_mobile/", "https://www.reddit.com/r/explainlikeimfive/comments/qtnuk/eli5_unlocked_smart_phones/", "https://www.reddit.com/r/explainlikeimfive/comments/3l6uiq/eli5_cell_phones_locked_to_carriers_and_unlocked/", "https://www.reddit.com/r/explainlikeimfive/comments/1a46ds/eli5_what_exactly_is_unlocking_a_phone_why_is_it/", "https://www.reddit.com/r/explainlikeimfive/comments/35pvpw/eli5_how_does_cell_phone_unlocking_work/"]], "score": [3]}}, {"q_id": "6qfu8r", "category": "Repost", "title": "How does a metal detector work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkwynwq"], "text": ["Usually through electromagnetic loops. An electric current is passed through a ring of wire to create an electromagnet. That ring of wire is often a disk-like detector on a handheld detector, or a wire loop embedded in a roadway. When there is motion with nearby magnetic metals -- either the loop of wire moves is swept over the metal, or a metal object like a car frame rolls over the loop -- it makes an interfering magnetic field, which changes the electricity flow in the coil. The simple detectors play a sound using the same current used in the loop. When the electromagnetic field changes, it can be heard in the speakers."], "text_urls": [[]], "score": [5]}}, {"q_id": "6qg7lz", "category": "Repost", "title": "What really is the difference between RAM and virtual memory?", "title_urls": {"url": []}, "selftext": "I constantly mix these two concepts/terms together.", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkx4f41", "dkx1a0n"], "text": ["RAM is physical memory. It's divided into various addresses. Accessing RAM addresses means accessing the actual memory chip. Virtual Memory is another name for RAM. In fact, another name for each RAM address. It basically means that Virtual address 100 may be accessing RAM address 203, or 1050, or whatever it may be mapped to. So there is a *mapping* that decides which virtual address corresponds to which physical address. For example, virtual addresses 1 to 100 may be mapped to RAM addresses 2301 to 2400. Virtual addresses are specific to programs (i.e. each programs has its own mapping of virtual addresses to physical addresses. This mapping is managed by the OS.) The reason? Well there are many. 1. Allotting virtual memory to programs allows them to work within a restricted space (say 1 to 1000) rather than address the huge RAM space directly. It simplifies things. 2. A program doesn't need to worry about where exactly it's loaded in RAM. It can access its virtual addresses (say 1 to 1000) and they are converted to the actual addresses in RAM by the OS. 3. Allowing direct RAM access can allow a program to access OS RAM and thus cause system problems or even system takeover. So from a system security standpoint too, it's better to have virtual addresses that are then mapped to the right place by the OS, securing itself from any malice a program may intend to cause. 4. Virtual memory allows a program to see its memory space as a contiguous block (say 1 to 1000), whereas the corresponding RAM addresses may be scattered (say 2501 to 2550 and 4431 to 4480). Another simplification fot the program, again managed and made to work properly by the OS. 5. It can allow a program to \"believe\" that it has more RAM space than it actually does. For example, the OS may give the program virtual addresses 1 to 1000 (so a block of 1000) while only the addresses from 1 to 500 may be actually mapped to the RAM. The rest may be unmapped. Now, most operations of the program may be satisfied by accessing virtual addresses 1 to 500. So the OS saved a lot of resources and space. If the program accesses an unmapped address, say 700, the OS will allocate more RAM addresses to the program, map them, and then allow the access. It takes a bit of time (milliseconds only, but then that's more than nanoseconds) but because its not often, the OS saves time and power and space overall. **This is what most people commonly understand by virtual memory, but it's only one of the functions of virtual memory, apart from the others outlined above.** Edit: words", "ram isn't virtual. its actual memory that your cpu stores information in. programs need to store data sometimes; data thats only relevant for *running* the program itself. thats the kind of data you *want* to have in RAM. when you don't have enough RAM, you can assign *space on your hard disk* as *virtual memory*: it *is real memory*, but not on the ram-sticks. that means that the cpu isn't talking *directy* to this virtualized memory: it first has to talk to the hard disk. conventional RAM is special, because the cpu can talk *directly* to it. in effect, real RAM is just faster."], "text_urls": [[], []], "score": [6, 5]}}, {"q_id": "6qgx0k", "category": "Repost", "title": "Why do people yawn?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkx603a"], "text": ["Probably due to a shortage of oxygen/build up of carbon dioxide when not exercising. Yawning is essentially a deep breath. It definitely is also partially behavioral, since most people tend to yawn when seeing others yawn - we might on a very primitive and subconscious level be communicating our willingness to fit in the group, or that we're tired. Nobody really knows one definite answer."], "text_urls": [[]], "score": [4]}}, {"q_id": "6qjg51", "category": "Repost", "title": "How do they measure the height of mountains on planets when there is no water? So how do they decide what's the 'zero'-point?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkxpuds"], "text": ["It depends on the planet/moon in question. On Mars zero elevation is the elevation in which water reaches its triple-point (when it can be liquid, gas, or solid). On the Moon, zero elevation is the calculated average diameter of the Moon."], "text_urls": [[]], "score": [8]}}, {"q_id": "6qkvr0", "category": "Repost", "title": "What's the difference between an embassy and a consulate?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dky0ubl"], "text": ["Yer not alone in askin', and kind strangers have explained: 1. [ELI5: What's the difference between an Embassy and a Consulate? ]( URL_0 ) 1. [ELI5: What are the differences between embassies, consulates and permanent missions? ]( URL_1 ) 1. [What is the difference between an embassy and a consulate? ]( URL_2 )"], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/5bazsg/eli5_whats_the_difference_between_an_embassy_and/", "https://www.reddit.com/r/explainlikeimfive/comments/1tluvs/eli5_what_are_the_differences_between_embassies/", "https://www.reddit.com/r/explainlikeimfive/comments/103xqv/what_is_the_difference_between_an_embassy_and_a/"]], "score": [5]}}, {"q_id": "6ql5r4", "category": "Repost", "title": "Why does the name for mother (mama, oma, amma, etc) contain an 'm' sound in almost every language, including languages with different roots (Latin based, Sanskrit-based, and Korean for example)?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dky36us"], "text": ["Because those are the first sounds toddlers make when they first start babbling. Parents end up associating sounds with themselves because it's nicer to think that their toddlers are saying things instead of just making random noises. Also, Latin and Sanskrit are related to each other. They are both Indo-European languages."], "text_urls": [[]], "score": [5]}}, {"q_id": "6qmjni", "category": "Repost", "title": "How do shows like Ozarks make money? There are no commercials and I already subscribe to Netflix", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkyeile", "dkyegu4"], "text": ["By itself, it doesn't make money. Together, collectively, with Netflix's library of shows & movies, it provides the content that gets you to subscribe and maintain a subscription. Ozarks is a Netflix house-produced title, Netflix made it, from their budget, and you pay netflix to watch it. Like, a newspaper article doesn't make money all by itself but buying a newspaper does.", "Netflix business model is to add new content as often as possible so you remain a subscriber or maybe somebody is really into Jason Bateman and so they give Netflix a trial and like the other content and also remain a subscriber. If they never added new shows and movies it would get stale very fast and would have a hard time with keeping subscribers."], "text_urls": [[], []], "score": [10, 3]}}, {"q_id": "6qpb9r", "category": "Repost", "title": "Why do different instruments playing the same note sound different?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkyx6y7"], "text": ["This is a frequently asked question. The Middle C in your example is just the \"fundamental\" tone, but notes from different instruments have more \"overtones\" or \"harmonics\" in different ratios, which define the tone. They can vary over time e.g. as a guitar string fades out, some overtones last longer than others."], "text_urls": [[]], "score": [3]}}, {"q_id": "6qrv9j", "category": "Repost", "title": "In Interstellar they land on a planet where every hour is 23 years on Earth. If possible how can this be?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkzj792"], "text": ["Yer not alone in askin', and kind strangers have explained: 1. [ELI5: how do the time differences between planets work in Interstellar? ]( URL_3 ) 1. [ELI5:Interstellar's relativity of time. ]( URL_2 ) 1. [ELI5:[Interstellar] Time moves faster is some places in space than others. ]( URL_4 ) 1. [ELI5: Aging in the movie Interstellar ]( URL_1 ) 1. [ELI5: In Interstellar, why does one minute on one planet equal four years on earth? ]( URL_0 ) 1. [ELI5: SPOILER ALERT\"Interstellar\" Time dilation ]( URL_6 ) 1. [ELI5:Re-watching Interstellar. Can someone please explain time/relativity - in particular, roughly 4 hours on one planet equating to 23 years on Earth. ]( URL_5 )"], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/3o6bum/eli5_in_interstellar_why_does_one_minute_on_one/", "https://www.reddit.com/r/explainlikeimfive/comments/2m21qf/eli5_aging_in_the_movie_interstellar/", "https://www.reddit.com/r/explainlikeimfive/comments/2qxwlh/eli5interstellars_relativity_of_time/", "https://www.reddit.com/r/explainlikeimfive/comments/361v7u/eli5_how_do_the_time_differences_between_planets/", "https://www.reddit.com/r/explainlikeimfive/comments/2lmevc/eli5interstellar_time_moves_faster_is_some_places/", "https://www.reddit.com/r/explainlikeimfive/comments/32fu9c/eli5rewatching_interstellar_can_someone_please/", "https://www.reddit.com/r/explainlikeimfive/comments/2lpzx9/eli5_spoiler_alert_interstellar_time_dilation/"]], "score": [5]}}, {"q_id": "6qs48o", "category": "Repost", "title": "How did nomads from hundreds/thousands of years ago deal with sun burn?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkzk9gz"], "text": ["Most people living in sunny areas had dark skin, or tanned pretty well. Those that didn't had to put something over their head (like a fabric headdress) or stay out of the sun midday."], "text_urls": [[]], "score": [6]}}, {"q_id": "6qs767", "category": "Repost", "title": "Why has Hollywood resorted to revealing every arc and twist of a movie, in a single trailer? When did thirty second commercial spots become not enough? Do they have so little faith in our attention span?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkzl1ix"], "text": ["I think you need to go watch older trailers, trailers from the 60s or 70s often had a narrator who would walk you through the entire story scene by scene. It was only later that trailers kinda turned into abstract music videos."], "text_urls": [[]], "score": [11]}}, {"q_id": "6qscx4", "category": "Repost", "title": "Why is counting cards in Blackjack so heavily frowned against or punished if all you're using is your mind. Are you not allowed to calculate with your brain when playing a game?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkzm7v5", "dkzm4w9", "dkznrre"], "text": ["The only reason the house exists is because the odds are stacked for them. Learning to count shifts the odds to you. If everyone did it they'd lose money and eventually cease to exist. This obviously takes the liberty of suggesting everyone possesses the intellect to do it, which they don't. But coming down on the few who can discourages other from trying and increases their profits. TLDR: they want more money", "Casinos don't make money on winners, and counting cards gives the player an edge over the house. All casino games are weighted in favor of the house.", "It's not illegal to count cards, however casinos reserve the right to refuse admittance to anyone they choose. If they suspect you of counting cards, first they'll wait and see how good you are at it despite distractions, free liquor, interruptions, etc, because counting cards incorrectly (losing count) actually makes someone lose faster than an average player. They love players who have a system but keep making mistakes. Those are favorites. But if the player persists and does well, then the casino will happily pay out their winnings and tell them never to come back again, because they've demonstrated that they'll cost the casino money again the next time. No charges laid in either direction, because both parties are doing things (mentally counting cards, adding someone to the blacklist) that are perfectly legal and within their rights."], "text_urls": [[], [], []], "score": [10, 6, 3]}}, {"q_id": "6qt2dk", "category": "Repost", "title": "How can a company like Netflix who is 20 billion dollars in debt still make profit for its owners etc?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dkzs7lq"], "text": ["Companies are constantly juggling debt, and $20,000,000,000 is really not a lot to Netflix. Consider that they are (as a company) worth about $80,000,000,000. The debt is (most likely) long-term debt, meaning they have years to pay it off. As long as they keep ahead of it (and they are) then it is not an issue."], "text_urls": [[]], "score": [10]}}, {"q_id": "6qtxko", "category": "Repost", "title": "why do we sleep with blankets? Even when it's fairly warm?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dl007bo"], "text": ["It's because our skin is a giant sensory organ. A change in air pressure or temperature tends to bother us when trying to fall asleep. Sleeping even with just a sheet provides us with a way to reduce the stimulus and sleep more easily. We also often feel vulnerable if naked and a blanket can solve that."], "text_urls": [[]], "score": [19]}}, {"q_id": "6qux1z", "category": "Repost", "title": "Body parts are usually around the same size among mutual people, but why does penis size vary drastically? What determines that a person will have a two-inch or five-inch or seven-inch, etc, penis", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dl0afg7", "dl0ch1l", "dl0loz5", "dl0l93b"], "text": ["Are you not talking extremes here? I did alot of sports so in the shower I inevitable saw alot of teammates their penis's. And there weren't to many extreme difference within guys with same cultural background. Just like somebody ears or nose can also be bigger or smaller. Different ethnic backgrounds is a different story. But that's probably genetic. Long story short I think the differences are not as big as you think they are, and that people focus to much on the differences. But as always the exception marks the rule.", "Body parts are not usually the same size amongst people. Our height alone ranges from 4 to 7 feet (roughly). Most people have roughly the same proportions, and most people have roughly the aame penis size (proportionally). Some people have longer arms or legs, bigger or smaller feet. Body size has a ton of factors, both genetic and environmental.", "The growth mechanism of the penis differs from most other body parts; the bones tend to grow proportionally, so limbs will usually retain proportion. The penis grows during puberty by responding to hormones, and it gradually becomes insensitive to these hormones, which causes the growth to slow down and, eventually, stop. So the penis isn't necessarily proportional to other body parts because of this. That having been said, most penises are average, just like with other body parts. On the Internet, you probably see a disproportionate amount of the extremes because they're more interesting.", "I'm unsure if a non-explanation is allowed in the comments, but I believe OP meant that, for example, two best friends of the same build, and other factors, who have the same length arms, legs, etc can have different penis sizes. OP is then asking what factor determines the differing penis size, as it seems to be unrelated to the person's overall build."], "text_urls": [[], [], [], []], "score": [41, 20, 8, 6]}}, {"q_id": "6qvca6", "category": "Repost", "title": "Why does the moon always appear smaller in photos than he does in real life?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dl08nzl", "dl0d4x9", "dl0qvqg"], "text": ["It depends on the lense of the camera. A lot of camera lenses have a wider view than our eyes, so something far away will look smaller. Also > than *he* does Bruv the moon is a chick.", "It really depends on the lens. Wide angle lenses over-exaggerate distances, [so the moon will appear further away - and thus smaller]( URL_0 ). Telephoto lenses, on the other hand, make distances look smaller than they are, so the moon will [appear bigger]( URL_1 ).", "Yer not alone in askin', and kind strangers have explained: 1. [[ELI5] Why does the moon look so tiny in pictures when it looks so large from where I took it? ]( URL_2 ) 1. [ELI5: Why does the moon appear smaller in pictures than \"real life.\" ]( URL_4 ) 1. [Why do pictures of the moon look smaller and zoomed out on your phone compared to in person. ]( URL_3 ) 1. [ELI5: Why does the moon always look so small and terrible when I try to take a picture of it with my cell phone? ]( URL_1 ) 1. [ELI5: Why do we see the moon as rather large, but through a camera it's seen as a minuscule dot? ]( URL_0 )"], "text_urls": [[], ["https://1.bp.blogspot.com/-jB8-gQRwv60/VDmfXUsLPVI/AAAAAAAAFl4/aDMBdk99Lj8/s1600/total%2Blunar%2Beclipse%2Bwide%2Bangle%2Bover%2Bhouses.jpg", "http://www.pxleyes.com/blog/wp-content/uploads/tele-images/telephoto9.jpg"], ["https://www.reddit.com/r/explainlikeimfive/comments/1ydjjm/eli5_why_do_we_see_the_moon_as_rather_large_but/", "https://www.reddit.com/r/explainlikeimfive/comments/1kngj0/eli5_why_does_the_moon_always_look_so_small_and/", "https://www.reddit.com/r/explainlikeimfive/comments/3mo41f/eli5_why_does_the_moon_look_so_tiny_in_pictures/", "https://www.reddit.com/r/NoStupidQuestions/comments/62aux0/why_do_pictures_of_the_moon_look_smaller_and/", "https://www.reddit.com/r/explainlikeimfive/comments/1j4xpt/eli5_why_does_the_moon_appear_smaller_in_pictures/"]], "score": [31, 4, 3]}}, {"q_id": "6qvksf", "category": "Repost", "title": "When things are loading on my computer, why does the status bar often jump quickly to 99% and then stay there for a long time?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dl0a7wa", "dl0a5dl", "dl0f3ec"], "text": ["The status bar is something that gets updated explicitly. So if the program has to load 100 data files the programmers just map one file to 1% of the loading process. But the 100th file might be way bigger so it may take longer. Or the 99% of the process is the loading of the data (again a linear mapping from data to load to %) and the last % is to unpack them. So overall it is bad programming of the developers OR something that just can't be timed. Like a download from a server, a version check etc. where the programmers can't know how long it takes in relation to other operations.", "Status bars show how much of a process has been completed, not how long each individual task takes. The increments of a status bar are not based on the time it will take, because figuring that out could be very computationally intensive and drastically slow the very thing it's measuring.", "It can depend on what is being loaded. Sometimes, when you file transfer or download something the final step of the process is something called a \"Cyclical Redundancy Check\" or an \"Integrity Check.\" When you download a file or an email, the place you are downloading the data will run what's called a hashing algorithm(SHA/MD5) against the file(s) you are downloading. The hashing algorithm will spit out a series of numbers and letters unique to that specific file or set of data and attach it to that data set or file. Once the step completes the download begins. SHA - Security Hashing Algorithm MD5 - Message Digest 5(although there may be more recent versions now.) At the 99% on your side of the download, the file has been received and the same algorithm is run again. The resulting series of numbers and letters that the algorithm on your end runs must match the original results that were generated on the other end of the download. This insures that the data has not changed in any way during the download process. Depending on the program you are using to download, it can also check for known hashes for that match malware. Example: You want to download a reddit app on your phone. Step 1. You connect select the app from the app store and tell it to download. Step 2. The app store accepts you request and runs the hash and spits out 12345 against the app. Step 3. The download begins Step 4. Your phone hits 99% and runs the same hashing process on the phone device itself. Step 5. The hash results show 12345 thus the integrity of the file is intact. Step 6. Install app"], "text_urls": [[], [], []], "score": [47, 4, 4]}}, {"q_id": "6qww8h", "category": "Repost", "title": "If I drill a hole directly from one side of the Earth to the other, then throw my sister down it, what would happen to her speed and trajectory as she approached/crossed the dead centre?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dl0k7b0"], "text": ["If the Earth was still and your hole was a vacuum, she would accelerate until she passes the core then begin to slow down, eventually stopping as she came out of the other side. Energy in = energy out. In reality though, she would slam violently into the side of your hole due to the Earth's rotation long before she made it anywhere close to the center."], "text_urls": [[]], "score": [3]}}, {"q_id": "6qwy1h", "category": "Repost", "title": "How did banking work before the internet?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dl0ny0n", "dl0ttao", "dl0sgj7", "dl0kt48", "dl0m8xl", "dl0sjvg", "dl0nqja", "dl0od5g", "dl0ud3m", "dl0uegg", "dl0udos"], "text": ["It doesn't specifically answer your question, but the movie \"Catch Me If You Can\" (Tom Hanks, Leonardo DiCaprio) *really* shows just how easy it was to abuse the length of time it took for one bank branch to communicate with another. People were able to get away with a great number of things that became extinct as soon as the Internet became the intermediary.", "I'll go ahead and preface this by saying that Extra History did a really quite good series on the [history of paper money]( URL_1 ) that deals in a fair amount of depth with how early banking works, so you should definitely check that out if it's something you're interested in. The history of how banking works is intrinsically tied up in the history of paper money, so... you know. Hold on to your butts. Originally, a bank was just a place where you stored your gold. So you didn't have to get your gold out and carry it around with you everywhere, banks started to issue their own promissory notes. Paper money, then, is really just a sort of shorthand that says 'Hey, if you bring this to a bank, they'll give you a certain amount of cash in exchange, no bamboozle'. Banks put out their own notes (which were really just receipts saying you had a certain amount of gold in their vault) and kept their own logs -- but that also brought with it a bigger problem. Say you live in Homesville, and your money is deposited at the Homesville Local Bank. You travel to Awaysburgh, with your Homesville paper money, and you try to buy something. The Awaysburgh shopkeeper takes your $100 Homesville note, looks at it, and says, 'No.' Well, shit. See, for him to get that $100 worth of gold, he has to travel all the way to Homesville to go to the Homesville Local Bank and withdraw that money himself -- which is a pain in the ass. Now sure, he can wait until he has more Homesville residents passing through and paying him in Homesville dollars to make the trip worthwhile, but maybe there just isn't all that much Homesville traffic in his little town. He might be waiting *months* until he has enough Holmesville currency to justify schlepping all the way to your podunk town to cash in your debt. Until he goes there (assuming there's no one else he can palm your Homesville dollars on), that money is worthless to him -- literally not worth the paper it's written on. That doesn't help you, of course, because you're now hundreds of miles from home and you've got paper money that works great in your local tavern, but here might as well be toilet paper. Maybe he'll agree to give you something in exchange for it, but to compensate him for his effort and the risk he's taking (after all, what if your bank collapses? What if he gets robbed during the long and arduous trip to cash in?)... maybe he'll just give you $50 worth of stuff instead, how does that sound? So how did the banks get around this system? Well, Homesville Local Bank can set up a branch in Awaysburgh, with a store of gold in each branch. (After all, it doesn't matter *which* gold coins you get, exactly, only that they're of the same value.) Then, your Awaysburgh shopkeeper can easily take your notes to his loval Homesville branch, cash it in, and the two branches can shuttle money back and forth between each other to keep the coffers full. That explains how branches of banks form, and why they work better: two banks in separate cities sharing funds and customers are vastly more desirable than two banks that work entirely independently. This was helped somewhat by the creation of central banks and the notion of legal tender -- that the government would take over the printing of banknotes and ensure that there was (at least, in theory) a level of stability in the value of a currency, rather than it being at the whim of whether your particular bank just disappeared one morning -- but that's [a long and surprisingly convoluted story]( URL_0 ) that doesn't really play into the main question here. It's a lot easier to transfer information -- which, really, is all bank notes are -- than it is to transfer gold itself. Over time, this transfer of information became easier (first by writing, then by phone and now by computers), but the basic principle is the same. As long as all branches have a way of checking just how much money is in a person's account, the actual *method* of checking only really changes how convenient and safe the system is. That's why now you can get your money pretty much instantly at any branch of your bank, even halfway around the world, but historically it might have taken some time.", "Phones Even working in retail as recently as the late 90s, we would have to call and verify checks over $500. Call up the customers bank, give the clients name and account number(from the check) and the bank would tell you if it would clear or not. They wouldn't give you extraneous info like how much extra was in there, or how short it would be, but they would easily tell you that yes, as of that moment, the check would or would not clear. Of course, this didn't account for things like someone going out and writing 10 different $500 checks in the same day when all they had was $600 in their bank account, so there was still a risk of checks not clearing even if you did get verbal confirmation.", "There were chains, but generally they did not communicate balances in real-time. People wrote checks and it took days to get the actually money.", "To really answer your question you need to narrow down which time period before the internet. In the 80's for example, there were ISDN and T1 connections (1.5 Mbps link) between bank branches and the bank's central mainframe. The 70's had T1's but likely only between larger institutions. So these were times of 3 to 5 day transaction periods for personal checking but 24 hour turn arounds on larger institutions transactions (large business transactions).", "> Were there chains of the same banking company? It depended on the state. In the 1970s, big banks in California had branches all up and down the state. In Illinois, branch banks were not permitted (or maybe 1 or 2? not sure). The idea was to protect small banks. When I was a kid, all banks closed at 3 PM. The bank employees then processed all the money and paperwork until their workday was done. If you had a savings account, you had an account book, about the size of a passport. When you added or took money out of savings, you handed the account book to a bank clerk, who put it in a machine. Then the clerk punched in the transaction, and the amount in/out, and the new balance was printed. Interest on savings accounts was calculated quarterly. I was a little kid at the time, but I think my folks said that you had to walk into the bank to get your interest recorded, or you would miss it.", "Banks used to me much more local... in fact, here in Illinois, banks weren't allowed to have multiple branches until the 90's. There were networks for ATMs going back to the 80's that shared information -- there were still ways for businesses to communicate/networks before the internet.", "Way way back, they closed on Friday at 5, and didn't open back up until Monday at 9. You had to grab money for the weekend before 5 on Friday or you were ass out. If you could find someone that would take a personal check you could alleviate this problem somewhat, but that wouldn't be easy.", "I worked in a bank branch in the 70s and 80s. Every afternoon 5pm or so, the armored truck would arrive and we had to be prepared with deposits, new account cards, documentation, etc. \"The bag\" was the center of our day. When a person or business opened an account, signers put their signature on a paper card, which got filed in the Operations area behind the tellers. We had to compare that signature to the one provided by each customer at the windows. No computers at our desks! I got the first one in my branch (downtown LA, 1981) Very common to place a ten day hold on any deposit from an out of state bank. *Edited to add ten day hold info", "We have systems such as BACS in the UK which started in 1968 and was an electronic \"clearing house\" all the banks would be connected directly to via leased lines and funds would be transferred between banks this way. Before that, telegraphic transfer would be used between banks and branches. Before that, we had runners and the mail system.", "Actually, I'm not sure the Internet has anything to do with how fast banks clear checks. They've used the ACH (Automated Clearing House) system for decades, which itself has probably been sped up due to process and technology improvements. URL_0"], "text_urls": [[], ["https://youtu.be/LrB9bS2VOLE?t=3m14s", "https://www.youtube.com/watch?v=-nZkP2b-4vo"], [], [], [], [], [], [], [], [], ["https://en.wikipedia.org/wiki/Automated_Clearing_House"]], "score": [186, 134, 77, 72, 51, 13, 12, 9, 6, 5, 4]}}, {"q_id": "6qwz2e", "category": "Repost", "title": "How are animals able to retain such muscle mass with a restricted diet yet humans need a constant amount of protein and nutrients to maintain much less muscle?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dl0mroi", "dl0pi7y", "dl0njp4", "dl0kvw5", "dl0mrie", "dl0plcy", "dl0q7di"], "text": ["The other factor at play in attaining and retaining muscles is myostatin. Myostatin is a protein (also called GDF-8) which inables/inhibits muscle growth depending on how much of it is present in muscle tissues. For example, Gorillas produce very little myostatin and, as such, are extraordinarily muscular without the need for extensive exercise. Humans, on the other hand, produce much more myostatin and so are less muscular and require regular strenuous exercise to attain significant muscle mass. This is due largely to our ancestors being very well adapted to running long distances. Our less muscular frame makes prolonged exertion possible as we're not burdened by a large amount of excess weight that additional muscle mass would add. A Gorilla is very quick over a short distance but it can't chase you for very long.", "**Humans:** Evolved as endurance hunters and foragers of high calorie fruits, nuts, and roots. Additionally our ancestor's primary survival tactic was climbing a tree (or wading into water if you believe in the amphibious ape hypothesis). Collecting this kind of food and in this way does not require a lot of muscle and uses mostly slow twitch muscle fibers (the less bulky of the two). So having a lot muscle is unnecessary and a calorie sink. Same applies to our way primary way of avoiding being eaten. Extra muscle just means there is less tree for you use avoid being eaten. Furthermore, humans have been using intelligence to supplement for muscle for a long time. **Typical Predator:** Most of these predators evolved as ambush and short sprint hunters. For them having a lot of muscle and of the fast twitch variety allowed them to succeed at the ambush. Ambush is a popular strategy among predators regardless of species because herbivores can easily pick where they are going to eat since their food is everywhere. So if an herbivore knows you want to eat them, they will not come anywhere near you if they can avoid it. **Typical Large Herbivore:** Large herbivores will quickly find themselves in an arms race with predators. The smallest of their numbers will typically be attacked and successfully killed before larger and stronger members of their species. This sometimes gets further reinforced by sexual selection strategies that enforce it further such as now cloven animals will have heading butting contests over control of a harem. Those that don't try to compete purely by muscle advantage will turn to some other strategy (speed, agility, herds, packs, etc.) to survive and get smaller as a consequence. **Small Herbivores** You are probably indulging in a selective bias in regards to these animals so you forgot about them. They use a very wide variety of hunting and predator avoidance techniques. As such they are not as likely to use enhanced and enduring muscle to survive.", "It's all down to the hormones and proteins in our body. We produce a protein called myostatin. This actively works to prevent the formation of muscle cells. We have a lot more of this than other animals that are considerably more muscular. In essence, our body biologically does not want to be muscular and tries to prevent it. We need to give it a strong need to be through a form of progressive overload coupled with the diet. So even if we had a gorilla's digestive ability and ate all the same food, we'd never naturally get as muscular because of our myostatin production.", "Herbivores are capable of digesting cellulose and so can extract protein from it. They can also extract other nutrients or synthesize them via gut bacteria or enzymes from plants. Carnivores are able to synthesis or extract all nutrients needed from meat. Being omnivores we have the advantage of being able to eat a wide variety of foods, but it is a trade off in not being able to get as much out of the foods due to not being specialized in extracting nutrients from them. We cannot synthesize as much from meats as carnivores, and we cannot digest cellulose at all unlike herbivores. We are less likely to run out of food due to being omnivores, but we may become deficient in something due to not being as efficient.", "Because human brains eat up such a huge % of our calories compared to other animals. A human brain is about 2% of the body's weight but uses 20% of the calories. Google turned up [this article]( URL_0 ) which includes this statement: > We do not expect BMR [basal metabolic rate] variability to explain a large amount of brain size variation, as there are other possibilities for maintaining an enlarged brain. Animals could reduce the size of other expensive tissues in the body (Expensive Tissue Hypothesis, Aiello & Wheeler 1995), or reduce energy allocation to locomotion or reproduction (Energy Trade-off Hypothesis, Isler & van Schaik 2006). It's saying that to feed our big brains, we have to increase our calorie intake (increased BMR), *sacrifice other tissues (i.e. muscles)*, be lazy to save calories, or some combination of the three.", "I would challenge the premise that we need constant protein and nutrients. There are plenty of people just on Reddit that work out, are muscular, and fast for days. Head over to r/fasting and see for yourself. There's lot of studies showing how hgh and testosterone are boosted during periods of fasting. Dr Jason Fung deals with this stuff a lot but fair warning there is controversy around some of his claims.", "Yer not alone in askin', and kind strangers have explained: 1. [ELI5: Why can horses and cows eat grass alone yet still pack on muscles while humans need more than just vegetables to bulk up? ]( URL_5 ) 1. [ELI5: how are cows and rabbits able to eat grass and turn it into muscle mass, but humans have to eat cows and rabbits to do the same thing? ]( URL_4 ) 1. [ELI5: How do horses grow such large muscles off of a diet consisting mostly of grasses? ]( URL_2 ) 1. [ELI5: How do vegetarian animals get the protein necessary to build and maintain muscle? ]( URL_1 ) 1. [ELI5: How do cows get so big eating grass alone? ]( URL_6 ) 1. [ELI5: How do large and muscular animals like rhinos, brontosaurus, and gorillas manage to get enough protein to maintain their muscles on a primarily vegetarian diet? ]( URL_3 ) 1. [ELI5:How horses are vegetarian and can convert that into muscle but I need to eat meat to build muscle? ]( URL_0 )"], "text_urls": [[], [], [], [], ["https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1834002/"], [], ["https://www.reddit.com/r/explainlikeimfive/comments/2c8ynz/eli5how_horses_are_vegetarian_and_can_convert/", "https://www.reddit.com/r/explainlikeimfive/comments/35lg09/eli5_how_do_vegetarian_animals_get_the_protein/", "https://www.reddit.com/r/explainlikeimfive/comments/1sh5xx/eli5_how_do_horses_grow_such_large_muscles_off_of/", "https://www.reddit.com/r/explainlikeimfive/comments/3nqd93/eli5_how_do_large_and_muscular_animals_like/", "https://www.reddit.com/r/explainlikeimfive/comments/617zbk/eli5_how_are_cows_and_rabbits_able_to_eat_grass/", "https://www.reddit.com/r/explainlikeimfive/comments/27ep7m/eli5_why_can_horses_and_cows_eat_grass_alone_yet/", "https://www.reddit.com/r/explainlikeimfive/comments/126jfc/eli5_how_do_cows_get_so_big_eating_grass_alone/"]], "score": [257, 71, 53, 29, 14, 8, 6]}}, {"q_id": "6qwzxy", "category": "Repost", "title": "How do people suddenly become allergic to things they weren't previously allergic to?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dl0l09y", "dl0q4s5"], "text": ["Do you mean something like a food that they could eat, then one day could no longer eat it?", "Yer not alone in askin', and kind strangers have explained: 1. [ELI5:How come allergies can be newly developed despite not being allergic to the certain product in the past? ]( URL_4 ) 1. [ELI5: How does the human body suddenly become allergic to a certain type of food, after years of eating it without any problems? ]( URL_5 ) 1. [ELI5: How does one become allergic to something? ]( URL_0 ) 1. [ELI5: How does my body get allergic to something that I wasn't allergic to a few years ago? ]( URL_3 ) 1. [ELI5: When I suddenly become allergic to something like shrimp, why is this happening and why does my body react the way it does? ]( URL_2 ) 1. [ELI5: Why and how people get allergies ]( URL_1 )"], "text_urls": [[], ["https://www.reddit.com/r/explainlikeimfive/comments/12hsu4/eli5_how_does_one_become_allergic_to_something/", "https://www.reddit.com/r/explainlikeimfive/comments/1mw6xf/eli5_why_and_how_people_get_allergies/", "https://www.reddit.com/r/explainlikeimfive/comments/2prgs1/eli5_when_i_suddenly_become_allergic_to_something/", "https://www.reddit.com/r/explainlikeimfive/comments/1n2sg9/eli5_how_does_my_body_get_allergic_to_something/", "https://www.reddit.com/r/explainlikeimfive/comments/5kazg9/eli5how_come_allergies_can_be_newly_developed/", "https://www.reddit.com/r/explainlikeimfive/comments/1epiky/eli5_how_does_the_human_body_suddenly_become/"]], "score": [8, 8]}}, {"q_id": "6r0uxt", "category": "Repost", "title": "why do sinks, with all that basin real estate, have faucets that barely clear the front edge?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dl1h5jb", "dl1ifo1", "dl1hni5"], "text": ["Because the basin is designed to be filled and used as a reservoir from which to draw water and wash your face, without your hands having to maneuver around the faucet.", "The sinks and the faucets are commonly sold separately. Someone didn't pay attention when they bought the hardware to go with the sink.", "Could not agree more. We don't live in past eras where water was scarce and had to be held in a reservoir to be splashed up to the face and reused for others. Opt for the large hook neck faucet at your home if you can."], "text_urls": [[], [], []], "score": [5, 3, 3]}}, {"q_id": "6r4goy", "category": "Repost", "title": "What are birthmarks? Why do we get them?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dl2bhnv", "dl2hcwz"], "text": ["A birthmark is a congenital, benign irregularity on the skin which is present at birth or appears shortly after birth, usually in the first month. They can occur anywhere on the skin. ... Pigmented birthmarks caused by excess skin pigment cells include moles, caf\u00e9 au lait spots, and Mongolian spots A significant proportion of newborns have a birthmark. Vascular birthmarks - a red, pink or purple blemish - are caused by abnormal blood vessels under the skin. Some people are born with pigmented birthmarks; these are usually brown and are caused by the clustering of pigment cells.", "u/lol_dubldown had this to say: > Yerr not alone in askin' etc etc > URL_2 > URL_3 > URL_0 > URL_4 > URL_1"], "text_urls": [[], ["https://www.reddit.com/r/explainlikeimfive/comments/3izzf2/eli5_what_is_the_science_behind_birthmarks_how_do/", "https://www.reddit.com/r/explainlikeimfive/comments/1m4f2f/eli5_what_are_birthmarks_and_howwhy_do_we_get_them/", "https://www.reddit.com/r/explainlikeimfive/comments/1sj3ml/eli5what_are_birthmarks/", "https://www.reddit.com/r/explainlikeimfive/comments/2l1ybr/eli5_what_are_birthmarks/", "https://www.reddit.com/r/explainlikeimfive/comments/5o99qw/eli5_what_are_birthmarks_and_why_do_they_appear/"]], "score": [6, 4]}}, {"q_id": "6r62gh", "category": "Repost", "title": "How come lakes don't get absorbed into the earth?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dl2klrf"], "text": ["The ground underneath the lake is already saturated, which means there's already as much water in the pores as there is room for. If you kept pouring water on the ground, it would stop instantly absorbing once the soil was saturated, and the rest would run off. In hydrology terms, we call the initial portion that gets absorbed the \"Initial abstraction.\" Like imagine it rains 2 inches tomorrow - maybe the first inch of that rainfall would get abstracted into the soil, the rest would run off, meaning that it would flow downhill along the surface of the ground until it encountered a body of water."], "text_urls": [[]], "score": [5]}}, {"q_id": "6r7uqc", "category": "Repost", "title": "What is beyond the universe?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dl2zd4b"], "text": ["> What is beyond the universe? There's nothing beyond the universe. The universe is not expanding \"into\" anything else; it's just expanding. > To my understanding, the universe is ever expanding at the speed of light. It actually might be going faster than that, although it's impossible for us to say. However, the **observable** universe is indeed expanding at C. > Theoretically, if we could travel at the speed of light mph + 1 and we eventually caught up with the universe, could we overtake it? What would we see? There's no way to answer this question; you can't go faster than C. I can't break the rules of physics and then tell you what those same physics would say about the situation you'd be in."], "text_urls": [[]], "score": [3]}}, {"q_id": "6rb2z9", "category": "Repost", "title": "My understanding is that airplanes, rockets, and objects within Earth's atmosphere use the density of the atmosphere to provide resistance which pushes the object forward. So how do satellites, the ISS, and objects in space use propulsion if they are in a vaccuum?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dl3olxl", "dl3ol78"], "text": ["Your understanding is wrong. Rockets don't push against the atmosphere to move forward. Rockets push out their own exhaust and as their exhaust gets pushed into one direction the rocket get pushed into the opposite one. Jet-engines also work that way but they need the atmosphere to provide the oxygen to create the exhaust while rockets bring their own oxidizer with them, which means that jet engines only can work inside the atmosphere and rockets can also work outside it. Things that have a rotor or flap wings do need an atmosphere to push against.", "Your understanding is only partially correct. Planes using props or jet engines need air to push forwards\\* (rocketplanes, which are rare but have existed, do not), and all planes (rocketplanes included) use it to generate *lift*. Rockets do not use the atmosphere for thrust; they use the reaction force from throwing mass out the back at high speed. Spacecraft therefore also use rockets and other reaction-thrust systems (ion drives, for example, or even just venting fuel) for propulsion. \\*: they need air to burn their fuel, and in the case of propellers, turbofans, and the like they also need it to \"push against\". Pulse- and ramjet engines don't need the air to push against; they only need the oxygen in it to burn the fuel."], "text_urls": [[], []], "score": [19, 3]}}, {"q_id": "6rcmqn", "category": "Repost", "title": "Gun Scopes. If you mount a scope on a rifle for example, the scope itself is obviously a few inches higher than the barrel. Wouldn't this make your round a few inches below target? How does a scope compensate for this.", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dl3zn6j", "dl3zee7", "dl40qqv", "dl4283o"], "text": ["Firing a weapon accurately is never a case of \"point and shoot.\" Beside the fact that your scope or sights are higher than the barrel, the bullet will drop as it travels due to gravity--the longer it has to travel, the more it will drop. They never go in a straight line. For this reason, sights are adjusted to be accurate at a certain distance. It's not precisely parallel to the barrel, though the adjustment is so slight you often can't tell. In addition to adjusting for the height above the barrel, you adjust it for the distance you're firing at. Say you adjust for a range of 500 meters--if you line a target at that distance up in your sights directly, you should hit it. (Ignoring wind, recoil and other confounding factors.) If it's further away than that, you'll need to aim above it, to account for the bullet drop. If it's closer than that, you may actually need to aim below your target to hit it.", "Any hand-held firearm that shoots a single bullet at a time such as a rifle or a pistol doesn't fire a bullet in a flat trajectory. Bullets will fall to the earth when fired from a gun over a flat surface at the same speed as they do when dropped. You can test this by firing a rifle on a level trajectory and dropping a bullet from the same height as the barrel at the same moment- they'll hit the ground at the same time. So, in order to hit targets that are more or less distant, the barrel of the firearm must be adjusted upward or downward to compensate for the distance, relative height, and other factors between the barrel and the target. If you shoot at something further away, you raise the barrel a bit and the bullet travels in an arc, going further than it would if you shot it level. This is done by adjusting the sights or scope- they'll generally have some means of making minor adjustments to them so you can set them for a specific range, and do so fairly quickly- you have to change your sight or scope settings to shoot at targets at different ranges, so you can compensate for the bullet's arc.", "During WWII many fighter planes had guns in the wings. If these were fixed they would fire parallel to each other, instead guns were harmonised (angled inwards) so that all the rounds converged on a single point normally around 300 yards so they focused on a single point. A similar thing is done with the sights on a gun, regardless of whether it's iron sights or a scope. Though it's the sight and a single round that are harmonised.", "As mentioned before the scope and barrel are zeroed. HOWEVER, something that is missed in a lot of explanations is that there are actually two zero points on the rifle. One at close range, one at far range, because the bullet follows a parabolic path it actually exits the barrel with a positive Y velocity and rise to a point 1/2 The distance to your target. The M16 for example have a zero target set at 25 meters with the rear sight elevation set at 8/3. Once you have zeroed at 25 meters you set the rear sight to 8/3+ 1 click. This sets you up to be zeroed at 25 meters and 300 meters. So at 300 meters aiming center target is identical to center target at 25 meters. At about 150-175 meters though the bullet is at the peak of its parabolic path and actually hits about 10 inches higher than your aim point ( I forget the exact difference.) So you aim slightly lower for targets at that range."], "text_urls": [[], [], [], []], "score": [17, 4, 3, 3]}}, {"q_id": "6rdz10", "category": "Repost", "title": "How is the main infantry rifle if the US military banned from civilian ownership despite the 2nd ammendment of the Constitution?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dl4a9cn"], "text": ["> A well regulated Militia, being necessary to the **security of a free State**, the right of the people to keep and bear Arms, shall not be infringed. STATES have the right to a well organized militia. PEOPLE have the right to bear arms."], "text_urls": [[]], "score": [3]}}, {"q_id": "6rfogd", "category": "Repost", "title": "Why are insects, like Houseflies or Moths attracted towards light sources?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dl4rgey", "dl4ow8g"], "text": ["Imagine you're building a tiny robot. You want the robot to travel far from its started destination, rather than move in circles. As then it'll have a better chance of finding another robot. So you program it with the following rule *\"keep the light on your right\"*. That way they can make course corrections to keep going in the desired direction. Now suddenly the light source is right next to them. So they keep spinning around it to re-orientate. Occasionally bashing into them.", "They used to navigate by light. When only moonlight or star light was the only source, they could travel by it, especially since no matter how much they moved, it would never really change position on them. This is why they repeatly fly into the light source. They don't understand it as a light bulb, just a moon they keep crashing into. Also, a source of light typically is not a danger and having a clear line of sight to light means there likely aren't any predators or other dangers in front of the insect, as they would block the light"], "text_urls": [[], []], "score": [8, 4]}}, {"q_id": "6rgd7c", "category": "Repost", "title": "Can you explain me how works Internet ? (thinking about servers, ports, cookies and that kind of stuff) Thank you", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dl4u1tt"], "text": ["Many layers of technologies and protocols built up - so much so that your question is *nearly* unanswerable in that form. ***A network;*** *The Internet*, at its most basic form, is just a network between two or more computers. This 'network' uses the TCP/IP protocol (mostly) in order to address messages to and from each computer. There are devices in-between the source and destination computers, called 'routers' which will make decisions about where to send the packets appropriately that they may reach their destination. It is not so dissimilar to a carrier pigeon mechanism, except it is much much faster and you get 'acknowledgement' of packets received by the remote machine you sent a packet to. ***A server;*** Is just a computer on that network with a (usually) fixed address, typically mapped to a domain name to make it easier, which receives and replies to 'request packets' (okay, a HTTP server in this case, aka 'web server' which it appears you are specifically asking about). This server may host various files and/or data which users may request from. ***Ports;*** Each program listening for requests on a server (such as a 'web server program' or otherwise) chooses a 'port' to listen for incoming connection. Each computer may have 65535 ports (that's not a random number, but that's a different question). Typically a web server 'listens' on port 80 for unencrypted requests, though they can (and often are) configured for any other ports. So a DOMAIN NAME gives you an IP address which gives you a COMPUTER's address: the PORT defines what program you are talking to on that computer. Most web browsers default to port 80 unless you specify otherwise, so when you type URL_0 it is assumed it will contact google's server on port 80. It is the combination of IP plus PORT which gives you a packet mechanism in TCP/IP. ***Cookies;*** Is something of a temporary storage mechanism agreed between browser developers and webserver developers - it is unrelated to 'the internet' in that it does not touch or have to do with the underlying technologies. Your web browser, such as chrome, may store cookies or it may not, depending on your configuration. It allows the website to identify certain things about you - whatever 'things' were stored in that cookie in the first place when the website requested your browser 'create' it. Each time you browser makes a request to that particular webserver for which the cookie belongs, it will include that cookies contents in the request, thereby allowing the webserver to recognize and/or react to whatever that was. ***Kind of stuff;*** This is endless, there are millions of protocols and technologies involved in all various things flying around on the internet."], "text_urls": [["http://www.google.com"]], "score": [3]}}, {"q_id": "6rhwuf", "category": "Repost", "title": "What are the physics behind a fire?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dl55ues"], "text": ["Fire is a chemical process. All the chemicals involves have mass, and temperature. It takes chemical bond energy and turns it into light and heat (which are really the same thing). It stops when the temperature, fuel, and oxygen conditions no longer are sufficient to sustain it. This is a frequently asked question, Search can find you many fine answers."], "text_urls": [[]], "score": [4]}}, {"q_id": "6ri86o", "category": "Repost", "title": "Why are films taped in 24 frames and other types of video media are in 60 frames.", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dl58w6i"], "text": ["This is oversimplified (and some would say wrong). When commercial films began to be produced in the very late 1800s and for maybe 15 years or so, various frame rates were experimented with. Good persistence of vision occurs at about 18 fps and that was a target for quite awhile (most cameras were hand-cranked). When a sound system was settled on in the late 1920s, it was sound optically printed on the edge of the film and the optimal film speed for sound was decided to be 24 fps. Videotape from my experience was always 30 fps and I heard several reasons for that, the one that made the most sense to me was that its could use 60 cycle ac current as a reference (early commercial videotape was developed in the US). But for higher resolution there were two interlaced (odd vs even horizontal lines) \"fields\" shot per frame and some people speak of video as 60 fps but it's 30. The PAL system (Britain and many other countries) was 25 frames or 50 fields per second. I haven't worked in that business for 20 years soI have no idea what goes on today but I'd expect video is still 30 fps US and 25 fps PAL."], "text_urls": [[]], "score": [4]}}, {"q_id": "6rm1ak", "category": "Repost", "title": "Why are Americans so in love with the Flag and their military?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dl60t9k", "dl60pgh"], "text": ["It's a pretty decent flag. Aesthetically pleasing color combination, and the design is a bit more exciting than a combination of stripes, but still clean and simple. 10/10, would represent 50 states and 13 original colonies again.", "It is just part of American culture. You could ask the same question of why the English are so attached to their monarchy. The US was founded in a relatively unique way and that leads a great many Americans to believe that our country has a unique role in the world. Many are exceptionally proud of that fact, and the subsequent international strength that they believe it allowed for, so they are proud of the objects and organizations that symbolize that exceptionalism."], "text_urls": [[], []], "score": [7, 7]}}, {"q_id": "6rmxd9", "category": "Repost", "title": "How can so many mobile games get away with clearly ripping off copyrighted material?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dl6b82y", "dl6a1bv", "dl6ad6o", "dl6xl7k", "dl70qzr"], "text": ["Games are expensive to make, taking lots of time and money. Good games take more time and money. In the mobile gaming world, I make more money when more people download my game, and I lose money in making the game. Stealing intellectual property from other people and well-recognized brands kills an entire flock of birds with one stone. Now I can get lots of people to download my game because of the brand recognition. I don't have to waste my time and/or money developing assets on my own. I don't need to spend lots of time hoping for my brand to get big. I can just sit back while the money rolls in. On the other side of the house, we have the people who made these brands or assets. They can come after me if they want to stop me from using their work for my benefit, but it costs money to do this. If they are a huge operation and I'm one person, it's probably going to cost them more money to take me down than for them to just ignore me. I'm also not the only one stealing from them. They have tons of little leeches like me doing the same thing. It isn't worth their time to go after all of us, so they focus on the biggest and most egregious ones until it stops being worthwhile. If they do come after me, so what? I take that one app down and put up another one ripping off someone else and carry on my merry way. Rinse and repeat if necessary. If they manage to take my entire company down, I'll just open another business and do the same thing again.", "To be honest, there isn't much regulation in mobile apps, especially on the Google Play store. Even more so when the apps originate in countries with loose intellectual property laws (like China)", "Without having an example, I can only really speculate, but it usually comes down to two things: 1) The mobile game is too small for the copyright holder to notice/care about going after. 2) The mobile game is already licensing the copyright material. EDIT: /u/Rpgwaiter deserves credit for this, but the point of countries with loose/non-existant IP laws (with China being an infamous example) is another big point.", "As an aside tho the creators of league of legends, riot games I believe is going after mobile game makers that are ripping off their content.", "Well kinda depends which games. There are actually assembly kits for games now that will run off similar templates and wouldn't be copywriting each other since were developed with the same game kit. So many of the 'city/town' builders come from that."], "text_urls": [[], [], [], [], []], "score": [100, 14, 8, 4, 3]}}, {"q_id": "6rmxrl", "category": "Repost", "title": "Why can't we remember the earliest stages of our lives?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dl6dwwv"], "text": ["In general, the childhood amnesia happens because at early ages the areas and structures of the brain responsible for the proper register of memory (and other cognitive abilities, as language) aren\u2019t developed enough, registering memories in a simple way. As we grow up, the register of memories gets more complex, and we forget a lot of things to make room for another memories. Also, after 7-10 years old, we tend to organize the events of life in a timeline, which can cause some confusion about when exactly some facts of the past really happened. Of course, depending of the importance or the frequency of an event, the memory can persist."], "text_urls": [[]], "score": [3]}}, {"q_id": "6ro2b5", "category": "Repost", "title": "Why is it acceptable for men to show their nipples in public/media but not women?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dl6iyfv", "dl6hbrw", "dl6hmg2", "dl6v4qp"], "text": ["Sexual subzones. A woman's chest area is biologically developed to show sexual development in tandem with other features. Males are biologically attracted to females who are on the prime of sexual development. So sexual zones are linked to sexual arousal. Men's chest area dont do anything i know of that comes close to boobs.", "Because much of our western law is written by Christians trying to force their religious values down everyone else's throats. They sexualize everything and think it is dirty.", "I know there are people out there blaming things like culture or religion, but that's not entirely it. The main thing is that women's breasts generally are much more sensitive then a man's, this was used since ancient times as a part of sexual acts. So over the years, a woman's breasts became associated with sex. A man's nipples weren't used hardly as much and never had the chance to be associated with sex. So basically a woman's breasts has become sexualized with a perfectly valid reason over a man's nipple", "Female breasts are secondary sexual characteristics, male breast are not. In many societies, displaying both secondary and primary sexual characteristics is considered obscene. Secondary sexual characteristics being things that develop/appear during puberty, eg. breasts, wider hips, pubic hair, etc."], "text_urls": [[], [], [], []], "score": [31, 11, 9, 6]}}, {"q_id": "6roka4", "category": "Repost", "title": "Why is everyone that pleads \"not guilty\" in a court case, but later found guilty, not also given a perjury charge (along with their initial charges)?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dl6ld37", "dl6vvnu", "dl6mraw", "dl6maq8", "dl6wt4h", "dl7c58s", "dl6nchj"], "text": ["> Why is everyone that pleads \"not guilty\" in a court case, but later found guilty, not also given a perjury charge (along with their initial charges)? A plea is not sworn testimony from the defendant, it is just the demand of \"prove it\" to the prosecution. Also it would act to derail the intended operation of the legal process; if you are going to be charged with perjury if you lose then why not lie your ass off at every opportunity? If you win you get off and if you lose you are going to be convicted of perjury for defending yourself anyway. And that is what it really comes down to: You have a *right to a legal defense*. To charge you with perjury just for pleading not guilty would violate your fundamental right to legal defense and would be a violation of human rights. You gotta' watch out for those.", "\"Not guilty\" doesn't necessarily mean \"I didn't do it.\" Sometimes the defendant may be arguing that although they did the deed, the act itself was not a crime. I killed him, but it was self defense. I took the money, but it was mine to begin with. My brain tumor impaired my judgement. I was following orders.", "In the US you aren't required to incriminate yourself; it's the prosecutor's job to prove you are guilty. You have an initial arraignment, at which the charges against you are established, your rights are explained to you, and you submit your plea. If you say you are guilty, the case goes straight to sentencing. If you say you are not guilty, you get your day in court. A 'guilty' plea doesn't necessarily mean you are guilty; it means you accept the fact that the prosecutors *do* have enough evidence to convince a jury that you are guilty. A 'not guilty' plea doesn't necessarily mean you are not guilty; it means you *do not* accept the fact that the prosecutors will be able to convince a jury that you did everything you are accused of. Since there is often a laundry-list of charges sought against you, 'not guilty' might just mean that you don't believe that they will be able to make some *specific* charge stick, even if you are found guilty of the rest of the charges. If you plead guilty at the arraignment, you are accepting everything you are charged with up-front as a package deal. So if you think that while you are technically guilty of breaking the law there are extenuating circumstances, and believe that a jury will agree with you, you plead not guilty and go to trial. If you hope to work out some sort of plea agreement, you plead not guilty and you go to trial. If you are totally guilty and you hope to weasel out of it, you plead not guilty and you go to trial. Pleading guilty, you're up against established sentencing guidelines and whatever mood the judge is in; pleading not guilty, you're (probably) up against a jury of your peers. All of that said, if you plead not guilty and it turns out to be a complete waste of the court's time because everything but your plea shows that you really *are* guilty, the judge can and sometimes will punish you for that. But (in our system) on its own pleading 'not guilty' is not perjuring yourself, because you are not legally required to help them prosecute you.", "Just to add on to what was already said here, a charge of purgery would require a completely separate trial as its not the same as what ever you were charged with and can't you can't be charged with it before its happened (charges have to be filed before the trial starts). It would basically double court proceedings of guilty people for little to no real gain to the public interest.", "Pleading Not Guilty doesn't mean \"I didn't do it\". It means (in effect) \"I am exercising my right to presumed innocence, and am requiring the prosecution to prove their case against me beyond reasonable doubt\". So there's nothing that is a 'lie' about that.", "Don't know about the US, but in Sweden the defendant is explicitly never under oath. Even when testifying. You can lie about the colour of the sky and it's not illegal.", "One reason: The initial not guilty plea is entered at the very beginning of a case - sometimes in the same court appearance when a defendant is assigned their court appointed lawyer. It is not advisable to do much of anything in court without talking to a lawyer. It is very common for defendants to appear and be told by a public defender on duty that everyone gets a not guilty plea at the beginning because that first hearing is just the beginning for potentially dozens of people. Getting into a back and forth with the prosecutor and the judge at such an early stage a) risks tactical errors by defendants who haven't talked to a lawyer yet and b) would take forever in cities and medium to large towns. If you're curious, go sit in your county's arraignment court for an afternoon then chat with the clerk. It'll be eye opening. Practices vary from place to place so don't assume it's the same in New Mexico as it is in New Jersey, but you'll leave way more informed about our criminal system. Perhaps obvious disclaimer: This answer centers on USA law only."], "text_urls": [[], [], [], [], [], [], []], "score": [75, 14, 12, 9, 6, 3, 3]}}, {"q_id": "6rqx2y", "category": "Repost", "title": "How does WiFi work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dl72wcs"], "text": ["A signal from your Internet Service Provider (ISP) comes into your house, through your modem and into your router. The router converts this signal into a Wireless broadcast (radio waves, but at a different frequency than the one your car picks up for music) which can be picked up by the hardware on your computer and is converted back into a useable format. Your computer then does the same in reverse. Data coming in and going out. Traditional wires are simply replaced by a signal in the air. Wi-Fi is also different from many other forms of radio frequency in that its range it's rather small. Typically no larger than the size of the average house."], "text_urls": [[]], "score": [37]}}, {"q_id": "6rtv3g", "category": "Repost", "title": "How can video games be played from a cassette tape?", "title_urls": {"url": []}, "selftext": "I'm talking about old 80s and 90s computers that played games (and possibly run other programs I guess) via tapes that looked like audio cassette tapes. How does that work? If you want to listen to an audio tape from the start you have to rewind it, not so if you lose a game on a tape and have to restart it.", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dl7osdh", "dl7vt8t", "dl7oukg"], "text": ["The cassette tapes were used for data storage. Just as you can have data CD's, and music CD's. The tapes were played and the data input into the computer's RAM. No game data was stored on the computer's tape itself. Data loaded much more slowly than happens now. But a program could be saved. There were no CDs, DVD, thumb drives, or any other storage devices. No Internet or cloud.", "Cassette tapes were used to store computer programs, but they weren't run straight from tape. You would first rewind the tape to the beginning, tell the computer to load the program, then start the tape. The computer would simply read the data from the tape and store it in its RAM; and this would be the complete program -- if a game, it would be all the levels and everything. Once the program had been completely loaded, you'd switch off the cassette player and instruct the computer to run the program. And to do that, the computer wouldn't need to read any extra data. Everything it needed was already loaded in its RAM. If you lost, no problem: the program would ask you if you wanted to try again, and if you did the program would simply loop back to near the beginning and run again. A simple program written in BASIC, for example, might include something like: 9960 INPUT \"Enter Y to play again. \"; x$ 9970 IF x$=\"Y\" OR x$=\"y\" GOTO 100 Of course, commercial games would normally be written in machine code, not BASIC, but you get the general idea: simply loop back to the beginning of the game. (Or near the beginning.) Bear in mind that these games were very simple -- a home computer in those days might have something like 64 kilobytes of RAM in total. Maybe 128. There wouldn't normally be many levels, and a good player ought to be able to complete them all in one session (eventually). Obviously, compared with today's games, there were drawbacks. You couldn't save the state of play at any point: if you loaded another program or switched off the computer (or even if the power supply glitched for a split second), the game would be deleted from RAM and the next time you played it, you'd start from scratch. It was floppy disks that made it possible to save high scores and other data in order to save state.", "They work the same way as floppy disks later and hard drives now: There is a file at the beginning that says what files are where. The computer had enough memory (what you would call RAM today) to do all the work."], "text_urls": [[], [], []], "score": [8, 5, 3]}}, {"q_id": "6rujiz", "category": "Repost", "title": "How do tides work? If it's high tide one place in the world and low tide somewhere else does that mean sea levels are uneven?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dl7u8pn"], "text": ["[This one has been asked before]( URL_0 ). TL:DR the moon pulls the water around making the sea-levels uneven. I haven't seen it in a while so i won't remove this one under rule #7."], "text_urls": [["https://www.google.com/search?q=site%3Areddit.com%2Fr%2Fexplainlikeimfive+tides&amp;oq=site%3Areddit.com%2Fr%2Fexplainlikeimfive+tides&amp;aqs=chrome..69i57j69i58.4159j0j4&amp;sourceid=chrome&amp;ie=UTF-8"]], "score": [6]}}, {"q_id": "6rxrc5", "category": "Repost", "title": "How can a fan cool me off if the air it's blowing is the same temperature as the room?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dl8id3i", "dl8ig31"], "text": ["If there's no breeze, the air immediately next to your skin quickly gets warmed up to nearly body temperature- and if you're sweating, quickly becomes saturated with evaporated water, and can't absorb any more. But if there's a fan on, the air is constantly being mixed, and there's always fresh air (at whatever temperature and humidity the room at large has) next to your skin. This is sort of the opposite of how a blanket or coat or other insulating garment works, by trapping the same (almost-body-temperature) air near your body, reducing the amount of heat that's transferred from your body to the environment.", "The air next your skin heats up quickly and will get close to body temp creating a pocket of air around you that you can no longer dump body heat into if it is still. The breeze disrupts said pocket of hot air and move cooler air in next to your skin, cooking you down."], "text_urls": [[], []], "score": [6, 3]}}, {"q_id": "6s0cgc", "category": "Repost", "title": "if borders between countries/states aren't straight lines, and aren't defined by rivers, then how are they defined?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dl927bn"], "text": ["There are a lot of ways to draw borders. One of them is to draw a straight, flat line. One is to follow a river. Another is to follow a high mountain range, where the border is placed on the contours of mountains, like you see in Northern Italy. For these, often times the whole range will belong to one country, or the line will snake between the peaks. Rivers are just one of a suite of natural boundaries that might create a border. Another is to follow ethnic, linguistic, or religious ties, marking individual townships as either one side or the other. You see this a lot in areas like Europe where borders have been defined by religious or ethnic warfare, and you see borders that snake around to keep communities to their own side. Lastly, borders sometimes form around actual positions surrounding a ceasefire or peace agreement. Whatever territories each army presently controls become parts of their countries, and it's left as that. You see that a lot in areas with very intense violence between factions that strongly distrust one another and view any kind of treaty as a betrayal of their principles, such as Israel/Palestine."], "text_urls": [[]], "score": [3]}}, {"q_id": "6s1tut", "category": "Repost", "title": "In English, what is the rule for the use of \u201cAn\u201d or \u201cA\u201d", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dl9dqu3", "dl9dy76"], "text": ["An is used for words that start with a vowel sound. Examples, An owl, an hour, an eight, an apple, an onion. A is used for all others.", "It has nothing to do with meaning. It has to do with how the word sounds. If a word starts with a vowel sound, you use 'an', otherwise, you use 'a'. Note this is how the word sounds, not how it's spelled. 'Unicorn' starts with a y sound, so you say 'a unicorn'. The h in 'honor' is silent, so you say 'an honor'."], "text_urls": [[], []], "score": [5, 3]}}, {"q_id": "6s2qzu", "category": "Repost", "title": "How did Salt and Pepper become the chosen ones of food spices?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dl9ofbp", "dl9z1cy", "dl9va7x", "dl9xzoa", "dl9xk7f", "dl9vf3r", "dla50lx", "dl9s3bj", "dl9m3bi", "dlacvlb", "dla9zsk", "dl9w35y", "dl9wc0h", "dlawldc", "dl9zrgw", "dl9uk3s", "dl9uokt", "dla41o5", "dla1dpd", "dl9tcet", "dl9xwmw"], "text": ["No it's way more interesting. Salt preserves food (by drying it) and is readily attainable (from the sea). Pepper preserves meat (piperine kills bacteria and repels maggots but is harmless to humans). Over time, cultures that embraced preservatives like this prospered and their cuisine spread. In India, they use a whole different set of spices. In China, there are even two different words for spices called La and Ma (edit see below). One is fiery like capsaicin and the other, referring to Szechuan pepper corn, is electric like a battery on your tongue. It's amazing. **Edit:** side note: people seem really curious about Szechuan peppercorn. It actually used to be illegal in the US but [as of 2005 you can now buy it]( URL_0 ) The reason salt and pepper came to grace restaurant tables with all those other spices out there is **French cooking and Louis XIV. ** At the time that formal dining came into fashion, French culture was influential throughout the western world. Louis XIV was an influential man as the king of France. He didn't like as much salt or pepper in his food but others did so he created the custom of having his chefs put it on the table rather than cooked in. The custom spread and western culture helped spread it all over the world. Edit: black pepper contains piperine not capsaicin. Edit 2: Chinese is hard. La (not Lada) and Ma are more nuanced and appear to refer to different things. La is the word spicy generically. And by region (Hunan vs Szechuan) Ma la refers to the numbing spice (that I described as electric feeling) see the comments below for detail.", "To add something slightly different to most posts I want to mention our nervous system, which works using salt (sodium ions). [Your taste buds are more receptive]( URL_0 ) in the presence of salt. Because of this, if you use a suitable amount of salt you can enhance the taste of almost any food. Be aware though, if you regularly use a lot of salt (but not so much to make the food taste disgusting) when you return to eating food with less salt it may appear to taste worse. As such, this 'enhance all taste' property of salt is desirable for the dinner table.", "Others have answered this question pretty well, but consider reading At Home by Bill Bryson; it's all about the modern home and goes into loads of detail about the history of apparently mundane things including why we have salt and pepper. It's also genuinely a funny read.", "Salt is an essential electrolyte. We need to have regular intake, just like other animals that will seek out salt licks, etc. If we don't have enough salt, or replenish it at regular enough intervals, cramps and other signaling/electrolyte problems will arise. For the same reason, we have evolved taste receptors that make any food with salt in it \"taste\" better to us. Pepper aids in digestion and pepperin, a component of pepper, helps the intestines uptake nutrients. So it's a co-factor in our getting better nutrients in our diet. For the same reason, it tastes good to us (much of our sense of taste has evolved around things we need). Things that we need to intake almost daily and/or with virtually every meal, are integrated into our sense of taste as seeming to complement everything rather than fundamentally altering the flavor profiles of foods. These things are known as seasonings, rather than spices.", "I remember reading the correct answer to this about 6 months ago. Hold my beer while I butcher it. Salt suppresses bitter tastes/unpleasant flavours in a lot (all?) foods. Which gives a more balanced flavour which humans like. You can add a small amount to coffee beans that are a bit old to negate the \"old and bitter\" flavour coffee gets later on. Given the choice, we'll tolerate something that's too salty over something that's too bitter. Pepper has crude antibacterial properties that humans can also tolerate/consume (there are other things that are anti bacterial but also anti-human).", "What about ketchup and mustard? I've done a lot of searching and can't find out where or why or when!", "It is not the case everywhere. I found out in Hungary that they use paprika for just about every food. It tastes good.", "Salt is a necessity. Our bodies require a certain amount of salt. Salt in high concentrations and peppers of various sorts are great for killing bacteria, and keeping food safe for longer periods of time.", "Mainly because of 3 reasons. * 1) Salt and Pepper are both fairly ubiquitous, being among some of the most abundant resources known to man. Salt, makes up much of our water, and is easy to de-salinate from water and then use, or mine from vast salt mines. Pepper, in it's various forms and incarnations, is fairly robust a plant and has many varieties that make them easily grown in most climates without many issues. * 2) They are some of the best spices known. Salt and pepper usually take very little to alter flavors of the food they are added to. Salt is usually tastable by humans by as little as 1 part per 1 million, and pepper at the most mild of capsacin levels can be tasted at around 1 part per 10,000. Both spices can be used at relatively small quantities that provide significant effects on the food it's used on. * 3) Mainly salt on it's ability to perserve foods. Salt has been used for millenia to dry and perserve foods. Running pepper in with it helps add flavoring to an otherwise VERY salty piece of meat once it's treated and produced.", "This has probably already been mentioned by those more eloquent than I, but we use to fight wars [over Salt as well]( URL_0 ). As already mentioned, because salt is used as a preservative, ships at the time would heavily salt all their food as they went on their months/years long trips discovering new parts of the world. Obviously with a lot of European countries basically travelling the same routes, there would be fights over the best spots to hold and restock their salt and other produce. Now, we don't have that much of an issue instead we have [Monte Kali]( URL_1 ) in Germany which is a literal mountain of salt which gets added to daily. The downside being the salt has now seeped into the earth and ruined the soil underneath. Quick aside, all of this was written off the top of my head from what I remember. If people wish to correct me or add to this, please do. Never thought I'd say this, but salt is super interesting.", "Mobile formatting ect All credit to /u/Flubb Reposted from [here]( URL_0 ) It got 'common' by desire for it. If you mean 'common' by quantity, that's to do with trade routes opening up. The Romans started it off - the sole Roman cookbook, purported to be written by Apicius, calls for pepper in 80% of the recipes, and Pliny the Elder moans about why pepper should excite so much enthusiasm amongst his contemporaries, considering that it cost so much to bring it from the East. On to the mediaeval period, pepper served a number of uses, including humoural - some foods were considered dangerous (eels for example, because they look like snakes) and so you needed to counter-balance or offset humours in food with spices - pepper being a hot, dry humour. They were also used in almost every dish concocted and therefore demand drove the spice trade. Related to this, spices in general were also used as medicine - I can't find much on pepper as medicine, but it was used to stifle a cold (being hot). There's also the allure of spices: spices were generally associated with Paradise - or being close to it - Prester John's land was supposed to have forests of pepper, which was only 3 days journey from paradise. As for the amount of pepper, that comes through the spice trade. Because generally it came from the Far East it cost an awful lot originally, but even that was dependant on the levels of import - some years it could cost you a lot of money (163 Gold dinars in Alexandria in 1333 for 500lbs), some years it would drop precipitously (11 years later in Alexandria, it had dropped to 75 dinars per 500lbs). As trade opened up with the East, pepper imports grew - during the 15th century, Venetian merchants brought in an average of 400 tonnes of pepper from Alexandria. Once the route to India had been discovered by the Portuguese, this only increased - one estimate of 4 Venetian galleys brought in 4 million pounds of spices (not all of it pepper), and another convey the following year brought in 2 million pounds, pepper making up about 1/2 of that amount. As pepper was generally in the hands of the Portuguese (and later the Dutch), they had a habit of raising the prices - and by the 1500s, pepper was an every commodity that you couldn't do without - this is why Queen Elizabeth I was so interested to support expeditions to find pepper.", "Piperine in large doses boosts the absorbtion rates of other vitamins(and drugs\ud83d\ude2c) aswell. I read somewhere it boosts the absorbtion rate of curcumin up to 2000% \ud83d\ude33", "I'd like to add that both help you taste your food by stimulating salivation which helps your taste buds actually tell what they're tasting. source: I cook for a living", "They didn't really, only in the west and only in countries culturally close to France. The east and the americas had there own spices. That being said salt and pepper are as popular as they are for three main reasons: mild taste/availability, usefulness as a preservative and lastly it was popularized by one of the later King louie of France. Either XIV or XVI. Whichever was sun king.", "Classic situation of big salt and big pepper working together to force out all the other spices in the pantry.", "Salary comes from the Latin word salarium, which also means \"salary\" and has the root sal, or \"salt.\" In ancient Rome, it specifically meant the amount of money allotted to a Roman soldier to buy salt, which was an expensive but essential commodity.", "Salt is necessary for survival. There's a reason why we've evolved to crave the taste of salt, sugar, and fat, because not having them at all is really bad. I have no idea why pepper is so common.", "Salt is special because the sodium and chlorine ions that we get from it are critical to our nervous system. If you don't eat enough chlorine and sodium you will eventually *die*; and since salt is the most plentiful (and edible) source of those elements on the planet our taste buds have evolved to crave it. Pepper appears to be popular for cultural reasons. My understanding is that it's a 'clean' spice which can add heat to foods without adding all sorts of other flavours. It does have bactericidal properties, but so do almost all other herbs and spices so I doubt that has much to do with it's prevalence.", "The real question is: How did they have a child and why did it come out as Paprika?", "Two nubian priestesses traveled to Egypt's old kingdom capital of Memphis and preached at length about those particular spices.", "Salt is one of the fundamental tastes detected by the tongue. The only recipes you'll find where you don't add salt are ones that are already salty. Salt is kind of the fundamental thing to add in order to bring out flavour. Pepper is 'hot', but doesn't have much of an actual flavour, so it doesn't clash with as many other flavours. Thus it is more versatile than many other spices."], "text_urls": [["https://www.google.com/amp/www.seattlepi.com/lifestyle/food/amp/The-Szechuan-peppercorn-is-back-after-a-long-term-1265515.php"], ["https://www.ncbi.nlm.nih.gov/books/NBK50958/"], [], [], [], [], [], [], [], ["https://en.wikipedia.org/wiki/History_of_salt#Cities_and_wars", "https://en.wikipedia.org/wiki/Monte_Kali_(Heringen)"], ["https://www.reddit.com/r/AskHistorians/comments/19mpok/i_understand_the_hostorical_importance_of_salt/"], [], [], [], [], [], [], [], [], [], []], "score": [14426, 2646, 842, 217, 151, 67, 51, 33, 33, 14, 12, 8, 7, 7, 6, 6, 4, 4, 3, 3, 3]}}, {"q_id": "6s5izq", "category": "Repost", "title": "Why is it a negative thing to be over-qualified for a job?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dla5mcg", "dla5lyn", "dla66r1", "dla86yo"], "text": ["If you're overqualified for a job, there's a good chance you'll leave when something better comes along. Employers prefer stability, particularly because some jobs have a cap on how high a person can perform.", "Let's put it like this, if you are over-qualified, it would be a waste of your knowledge having you in a lower position. Also your demands on salary are probably higher than what's offered for the position.", "It means that you are more likely to be unsatisfied with your job and seek employment elsewhere. It also means you are likely to find said employment. Your skills have marked you as a temporary worker and many places are not willing to put in the time and effort to train you if you are not going to stay.", "Hiring someone is a huge pain in the ass. You need to advertise, sort through a shitload of resumes, interview and then make a decision. Once you hire someone it takes weeks/months to get them accustomed to the position and sometimes even a year before you'll turn a profit on that employee (depending on industry and position). Also, there's often investment in training that needs to be made. So overall going through this process only to have the employee leave or not work out is a huge headache and can cost a lot of money. For a smaller company making a single bad hire can kill their profit for the year. So hiring is one of the biggest choices a manager makes, and it comes with risks. The overall hiring process is targeted to minimize those risks. You want someone qualified, sure, but also someone who can manage the required interpersonal relationships. Someone who won't disrupt the team dynamic. And lastly, someone who will stick around after you've put all this investment into hiring them. It's that last part managers are worries about with over qualified people. They know there's a good chance you'll leave and they'll have to do the whole hiring process all over again. This would be quite the loss and an overall pain in the ass that they'd rather avoid."], "text_urls": [[], [], [], []], "score": [13, 5, 3, 3]}}, {"q_id": "6s6pe9", "category": "Repost", "title": "What makes our bodies twitch right before we fall asleep?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlaicit", "dlaevrh"], "text": ["It's called a myoclonic jerk and it's caused by your two nervous systems (yes... You have 2- one you control, like your legs; and one you don't, like your heart) realigning to night time mode that allows you to dream of running without actually running.", "Hypnic jerk (sp?) Basically the mechanism that tells your body it's about to fall off of a tree branch and get devoured by hungry lions, tigers, bears, etc. waiting below."], "text_urls": [[], []], "score": [4, 3]}}, {"q_id": "6s841b", "category": "Repost", "title": "Why were Native Americans so far behind Europeans technologically and culturally?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlat2bc", "dlas6n2", "dlb1zy6", "dlb34yx", "dlarcaw", "dlb6n2f", "dlb6vj6", "dlas3u2", "dlatkjv", "dlb81f0", "dlaszl0", "dlb71ad", "dlb6bvq", "dlb6deh", "dlb8dmw", "dlatgrz", "dlb4qpy", "dlb7are"], "text": ["This is a really fascinating question. There's a book I highly recommend reading that discusses this very topic, called \"Guns, Germs, and Steel\" by Jared Diamond. For the sake of answering your question, here's a couple of the reasons the book posits. First and foremost, the relative ease of domesticating wheat compared to maize. The type of wheat that was grown by early civilizations was genetically almost identical to wild wheat. Maize required extensive artificial selection to become even the rather mundane crop that it was when Europeans arrived in the Americas. Wheat could also spread equatorially, which means fewer adaptations were required for surviving in different climates. Maize was domesticated in South America, had to adapt to survive the much hotter Central Americas, and then adapt again to survive the cooler North America. Early human's artificial selection to make maize a proper cereal crop took millenia, whereas domestication of wheat occurred quickly. Wheat also has a lot more protein in it than maize, which means it requires less supplement from other foods. All this stuff seems little, but the presence of a robust and nourishing cereal crop was one of the foundations of every early civilization. Settling down means you can't forage, and providing surplus food allows for people to specialize in things like \"making tools\" or \"writing things down\" instead of hunting all the time. These advances occasionally lead to improved farming techniques, and consequently a larger food surplus. The lack of domesticated animals in the New World was also likely a contributor. Humans brought protodogs over the land bridge from Russia during the last ice age, but by then we were already superpredators. Almost every large land mammal that existed in the Americas was extinct within a few thousand years (bison and llamas being two of very few exceptions). Species like horses, pigs, cows, and sheep had evolved alongside humans and had developed means of avoidance or cooperation. The humans that migrated to the Americas were almost like an invasive species. Of the few large animals that the Native Americans left alive, only one ever was domesticated, the llama, and its use was quite isolated. Domesticated animals (especially the horse and cow) allowed Eurasian civilizations to benefit from nonhuman labor, pulling plows, turning mills, all work that is backbreaking for humans and... somewhat less so for other animals (I'm not going to pretend that humans were nice to these animals, but having four legs is an advantage in pure traction). Living in close proximity to such a diverse group of animals also bred powerful new diseases. Tuberculosis, for example, is believed to have jumped to humans from animals. These diseases grew more powerful in the many densely-packed cities that formed in Eurasia, and ravaged the defenseless Native Americans when the two cultures met. These advantages basically gave Eurasian people a couple thousand years or so head start, and as I mentioned before, the production of surplus food allows specialization and technological innovation, which often compounds the surplus and drives further growth. But I do highly recommend that book if you're interested in the development of ancient cultures.", "The Inca were not aware of the Aztec, and the Aztec had little contact with the plains Indians. The plains Indians had little contact with Inuit tribes. The north-south orientation of the landmass meant that technology developed by one nation would take many centuries to disseminate because travel was so difficult. Jungle empires can't cross the desert, and desert tribes can't cross the jungle. In Eurasia, you can stick to a single climate band from Madrid to Seoul. The Romans knew of the Chinese and sporadically traded with them, allowing technology to spread quickly across nations.", "How were they culturally behind? How can one even make the distinction between superior and inferior culture?", "I just want to add to what other people said. An interesting geographic aspect of Europe is that it is separated by small - but passable barriers. England is separated from Europe by a channel - not an ocean. Italy is separated from Europe by the Alps, but not the Himalayas. This led Europeans to split into slightly isolated countries. They were separated from each other - but not enough to prevent trade or war. So you ended up with a pretty much constant state of trade and war. Both of those things lead to technological innovations. To put it another way - if Europe was one big plain with no rivers or seas separating it into different countries - it probably would have been ruled as one Empire for thousands of years without splitting and fighting, and technology would have stagnated.", "Culture is not something that can be measured by a specific metric. There is no way of showing that native Americans were culturally behind. As for technologically, there were many large cities of indigenous people across the Americas. In fact the Native Americans were the ones who taught the Europeans how to properly rotate crops, and how to ensure they would have food for the winter. So the short answer is they weren't. They were more advanced in several fields, their lifestyle however was more intune with living in concert with nature instead of destroying it. As a further aside, when Europeans reached the Americas, the indigenous people had just been ravaged by a plague that wiped out 70-90% of the population. Frankly we are still trying to piece together what life was like before the Europeans got here.", "Culturally they weren't behind. Cultures evolve to fit a people in a particular environment. As for technology it depends on what areas you are speaking of. Native Americans mastered the art of medicine and human biology. Indigenous pharmacology was the most advanced in the world, with alkaloids such as quinine well known by Native South Americans ahead of Europeans or other nations. Only 60 members of the original 500 survived in the Jamestown colony. Most had died of scurvy and the rest were dying. When the local tribe saw their condition they immediately recognized it and treated those still alive with tea made from green pine needles. This cured them of the scurvy. Scurvy is caused by a lack of vitamin C and pine needles are a great source of vitamin C. Scurvy was also the bane of sailors costing many lives. The only food that could be preserved on a ship was salted meat and a hardtack type bread. After word of the Jamestown miracle Europeans started to figure out what the problem was. All ship started carrying limes on them. That's when the British sailors earned the nickname \"limeys.\" And to this day they still carry the nickname. As for agriculture Native Americans were far more advanced than Europeans. In the the Andes of South America the natives had almost 3,000 separate types of potatoes with different features and that grew at different elevations. Native Americans gave us corn, beans, potatoes, tomatoes, and peppers; in terms of how the food is grown, produced, and preserved; and in terms of the culinary arts. A really good book on what the rest of the world acquired from Native Americans. The title is \"Indian Givers\". It list and explains what every group contributed to the world. The list is very long with things like chewing gum, rubber, and even what they contributed to the Industrial Revolution. Here's the Wiki article on the book: [Indian Givers: How the Indians of the Americas Transformed the World]( URL_0 )", "Because 90% of the human population lived on the other landmass. Europe, Asia, and Africa had always been interconnected. With 90% of the population on that one great interconnected series of continents, it's no wonder that the most development happened there. Really, given that people on both landmasses started out as hunter-gatherers, as all humans had been for 95% of our history, I think it's pretty amazing that agriculture and civilization arose in the Americas in a completely independent event from its rise in Euraisa.", "This is a eurocentric way of thinking. Native Americans valued technology differently than Europeans. Europeans have been historically willing to destroy their own environment in the pursuit immediate returns in economics and technology. Native American (who are and were a disparate group of varied cultures, not the single, one-dimensional group they are often made out to be), did in fact, use technology that was relevaant and useful to them and early europeans invaders benefitted from it in their invasion. However, Native American culture tended to be more forward-thinking, considering the long-term consequences of actions. The cultural superiority of Europeans is based on Europeans valuing their own culture more highly, conveniently forgetting the Native American source for some pretty major facets of modern culture (like the Federal system of democracy), and the later loss of Native American culture following European-caused disease, relocation, and systematic suppression. You can easily find a huge list of Native american contributions in Wikipedia, [here]( URL_0 )", "Paraphrasing CPG Grey: Animals. \"What?\" Yeah, animals. Domesticated livestock animals.* Apparently not having tons of free, manageable food and extra labor does a lot to harm a civilization's productivity. Anything that would have gone to research and war went directly to food, so they were super far behind. By extension the lack of farm animals filling cities with feces and generally being smelly and gross left the Americas bereft of their own fatal diseases, meaning that without extra food, labor, and contamination, they were both biologically and technologically vulnerable. The diseases were killing way, way before the European Invaders ever even had to lift a musket barrel. Edit*", "I suggest you re-ask this question in r/AskHistorians This sub has too many folks talking out of their butts about stuff they don't know anything about, or seeing needless offense in your question. The short, short summary I will give you is that European technology was a result of building off technology that came from many different cultures from not just Europe, but Africa, Middle East and Asia. There was constant trade from the dawn of human history that resulted in a lot of technological breakthroughs. You had tons of cultures sharing technological secrets and just building up and up. The Native Americans were completely cut off from these achievements, such as the major achievements made in metallurgy and the sciences. While some south american tribes did have metallurgy techniques like smelting and molding, it wasn't anywhere near as advanced as what was developed on the other continent, and they remained isolated from the tribes in the northern continent. For technology to prosper requires trade, and the development of long distance trade routes seen among Europeans, Easterners, Africans and Asians never occurred in the Americas until the Europeans came over and created it.", "If you're thinking about basic elements like the invention of the wheel, is seen in Aztec toys. They didn't use it for transportation because the terrain didn't allow it. They were also at a disadvantage when traveling long distances because they didn't have horses, which hinders cultural exchange. In Europe it was very easy just to start riding a horse and end up in Mongolia.", "In one word: Commerce. But it gets more complex when talking about cultural advancements. Here comes an expample. The Gunpowder was invented in China and came to Europe through the Silk Road. In this way, you get rid of the necessity of Europeans to dicovery the gundpowder for themselves. Edit: changed discovered to invented.", "If you think of \"advanced\" as having coats and ships then you have a very narrow way of thinking. You're talking about groups of people living in VERY different worlds. Yeah your European dude had a ship, but he couldn't survive for months at a time in the wilderness. He didn't have the same traditional healing methods passed down. Not all Natives died the second they got sick (until they were exposed to that which they had no immunity to). They had their own ways to treat illness. They survived from the land, and they fought and won battles. You can't even compare the two. It's like comparing a bicycle to a hairdryer.", "I can't see any particular linearity that represents cultural and technological superiority. Europeans were nasty and smelly and good at sticking sharp things in people. Could build ships and so on. But they didn't have the geometry of the ancient Egyptians etc. Cultures in the Americas had very large cities with all kinds of nice features. Just a different thing going on. Mostly dead when explorers from the European invasion came through. Europeans sent waves of death ahead, clearing the country. We've also in the US been misled about the original cultures as part of the whole \"manifest destiny\" thing. Make the savages into real people who had cities and nations rise and fall, it becomes much more ethically difficult to push them aside. I can't see any reason to pick one time period to compare. Just coincidence what was what on each side. Civilizations rose and fell in both domains.", "This is a loaded question. As you can expect, there are many reasons, some of which are still being debated. One main thing to remember about the Native Americans is that they, until the first Europeans began to come (1500s ish?) and interact with them, didn't have any contact with the the rest of the world. Contact between Asia and Europe and even Africa spread many cultural ideas and innovations. The native Americans didn't have the Silk Road. Simply put, it's hard to be as advanced as the rest of the world when you're working all by yourself. Why didn't the inuits in the north trade and diffuse \"advancement\" with the Iroquois in modern New York, or with the Incans and Mayans? An [interesting (and probably true)]( URL_0 ) theory is that this is due to the axis of the americas versus the axis of the rest of the world. Throughout the rest of the world, people spread and migrate easily because they generally are moving on an east to west axis with much less change in latitude. The Americas are relatively narrow in comparison to the \"Old World,\" and most \"spreading out\" would be done on a north-south axis. This is MUCH harder to do on a large, noticeable scale because different latitudes come with different temperatures, climates, etc. People in modern day New Mexico did not have the necessities to travel to modern day Alaska, and vice versa. It's important also to note that while the native Americans as a whole weren't as \"advanced\" as the rest of the world, certain societies (specifically the Incas and Aztecs) built massive and advanced cultures and civilizations that awed even the Spanish conquistadors. Edit: I'm so happy that everyone is mentioning Guns, Germs, and Steel by Jared Diamond. This is truly a great book that broadens your world view!!", "Disclaimer: I'm not an expert I think if there is an anwser to that exponential growth plays a big role in it. A few hundred or even thousand years are not all that much time. A human life span is ca. 80 years so year 0 lies just 25 human lifes in the past. It's crazy if you view it like that. Most of our civilized history spans across just 150 human lifes (12k years). Now if you think about how quickly technology can develop once it spontaneously emerges it's quite obvious that there have to be major differences between cultures on earth. Especially when there is no real communication as there is today. If someone develops a new app pretty much the whole globe has access to it at the same time. Who ever developed the wood app called \"wheel\" first probably had a major advantage over all others on the planet for many years or decades if not centuries. During that time new technologies emerged faster because you could now bring food to the table more quickly and work on new crazy things more often. Technology grows exponentially because development accelerates new development. Like that small differences in the beginning lead to very big advantages in the future. You can compare it with today aswell. Who ever will develop a strong A.I. (artificial intelligence outperforming the human) first will be able to develop things humans could not develop without it sooner. It's like the wheel 2.0. or maybe 3.0. I believe 2.0 was the computer. Anyhow, important to note is who ever will get strong A.I. first would be like the europeans back then while the others would take the role of native americans. Unless we share our progress with everyone which is what OpenAI is all about I think. So I'm quite positive about the future but I'm not sure if that is a good answer to your question.", "If technology means to be ahead, what does it mean now that people are actively choosing to use technology less? Does it mean we've regressed or have we evolved as a society? And what does it mean to be culturally behind or ahead?", "Consider the kind of tehnologies where Native Americans were obviously ahead of Europeans: canoes, winter clothing - versus the kind of technologies that Europeans were obviously better at - weaponry, cavelry. Native Americans dedicated their technology to survival; Europeans dedicated it to conquest. It's also worth bearing in mind the kind of associations between Native American belief and the natural world, versus the kind of attitude a European might have had; if you can choose between a massive, polluting factory that produces luxury goods, and a sustainable society that puts limits on what you're able to produce, then the kind of choices made would reflect on that society. I also get the impression that Northern North America was mostly populated by nomadic societies and therefore didn't stay in one place to build towns in the way Central Americans, Asians and Europeans did."], "text_urls": [[], [], [], [], [], ["https://en.wikipedia.org/wiki/Indian_Givers:_How_the_Indians_of_the_Americas_Transformed_the_World"], [], ["https://en.wikipedia.org/wiki/Native_American_contributions"], [], [], [], [], [], [], ["https://www.amazon.com/Guns-Germs-Steel-Fates-Societies/dp/0393354326"], [], [], []], "score": [452, 399, 242, 50, 49, 36, 25, 19, 16, 15, 14, 5, 5, 5, 5, 4, 3, 3]}}, {"q_id": "6s92hm", "category": "Repost", "title": "Why do toilets(in america) use clean potable water?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlayctq", "dlay3a8", "dlb6okh", "dlayy6y", "dlbehoc", "dlb56du", "dlbeu9v", "dlayctt", "dlay8f4", "dlbcuvo", "dlb65e1", "dlay0xc", "dlaywzt", "dlbbbmi", "dlay2ok", "dlb6iit", "dlb80bi", "dlbbdjm", "dlbd7wv", "dlbak6d", "dlayy7y", "dlb00hm", "dlbcdy6", "dlb76u8", "dlbffh3", "dlbfns8", "dlbd22q", "dlbb8aa", "dlb9fo0", "dlbb1dv", "dlbftyt", "dlbe923", "dlbf6vo", "dlbeobi", "dlbawwq", "dlbdg0a", "dlbdhyo", "dlbccg0", "dlbgvc0", "dlbcg6x", "dlbfprk", "dlbo6uh", "dlbftmd", "dlbimqo", "dlbju6b", "dlbgewy", "dlbgfqk", "dlb9l0m", "dlbgvr0", "dlb7md8", "dlbbg5c", "dlbhub9", "dlbg48q", "dlbbf22", "dlbapac", "dlbeqws", "dlbihen", "dlbhri5"], "text": ["Our potable water supply is one thing I think we take for granted in North America. Using gray water would be waay better of course. You CAN get toilets that are specifically designed to use gray water, or some toilets that have the sink right _over_ the toilet for this purpose. Its just specialty bathroom ceramics (therefore $$$) and additional plumbing $$. If we were to have a separate supply system to take say industrial gray water (industrial outflow, water from laundromats, storm sewers etc.) - which would be ridiculously expensive to put in - then you have to worry about where the water came from. Last thing you want is hazardous chemicals dumped accidentally at the soap plant to vent fumes through every toilet in town. So now you're into water testing and quality analysis and maybe pre-treatment... hey, we already have a water plant that does that. Good idea in practice, essentially doubles your water supply infrastructure. No, the only way to do this on a practical home level would be for you to collect your rainwater in a cistern with solar pumps to move it to a tank in your attic. You'd still need to change the feed for your toilet and run new lines to each bathroom but its doable.", "Water treatment is actually pretty cheap, whereas running another set of plumbing or having a built-in greywater system is more expensive. There are places where the true cost of clean water is not really factored into the price (e.g. the desert southwest) and in some such places people are beginning to install greywater systems so they can save water and be more environmentally friendly.", "I used to work on a small island where fresh water was limited. There *had* been saltwater supplied directly to the toilets, but maintenance was a big issue.The site was built before plastic plumbing was available. So the toilets were connected to fresh water. Some years later, during a major rebuild, grey water flushing *was* considered, but was rejected due to complexity and maintenance issues. New low-flush toilets extended an improved fresh water supply.", "Because then we would need another entire system to bring dirty water in for your toilet. As it is, a building only needs clean water in, dirty water out. This is easy to design. Otherwise, you'd need clean water in, dirty water in, dirty water out, and the dirty water in would need to be totally separate to avoid contamination. Also grey water can carry lots of diseases and animals drink out of the toilet all the time.", "About 10 years ago, I used to work in Business Development and Engineering for a district steam company. We had 13 miles of supply piping, but the condensate was not returned back to the plant. Most customers just sent that water down the drain. However, I used to tell all of my customers that the water was clean and could be used for any non-potable use. The main thing preventing usage was the piping costs. However, in cases of new construction, I found that several clients took advantage of this \"free\" water. One client pumped it to a holding tank on the roof and that was the primary source for toilets. They had a valve on the domestic water line that would be engaged if the holding tank emptied out and for the summer when steam usage was generally non-existent. I also had a few clients that used the water for power washing plaza areas or for water fountain make-up water. There was some code requirement that did not allow usage for irrigation, but that would have also been a good use of the condensate. However, I was dealing with a built up downtown area, so irrigation needs were minimal even if allowed. On a related topic, a much higher percentage of clients used the condensate to pre-heat their domestic hot water since getting the energy out of the condensate can be easier than using the condensate water itself. Best of luck, Sol Rosenbaum, PE, CEM, CPMP I have written some articles on LinkedIn geared towards young engineers I think you might enjoy. I\u2019d really appreciate it if you could have a look and give me some feedback on my articles. The link is URL_0", "Two points: 1. Mine doubles as my dogs water bowl. 2. My bidet needs a clean cold water line. I don\u2019t want grey water shooting up my butt.", "The most efficient system I've been able to design takes waste water from showers & sinks condensates, washer etc and drains to a small settling tank, bout 500 gallons. The overflow goes to an ejection pump system that pumps to a tank at a high point to gravity feed all the toilets. That tank requires overflow switches to tell the ejection pump to stop pumping when it is full at Wich point a bypass valve opens to pump into the sewer system. This whole thing is easily 5-8k on top of 7k system. Not to mention all code violations required to accommodate this....aaaand you've stopped reading by now because this is boring as shit. At the end of the day all this extra juice and material negates any environmental benefit. Low flow toilets only use 1.2 gallons per flush. The sink in the tank is a good idea but it's illegal by universal plumbing code. Source: I own a plumbing company.", "Because the water sits there, in the bowl, between uses, it has to be clean. Otherwise the toilet is just a cesspool (pun intended) for all manner of germs. The other major reason is that it is easiest to replenish the water after flushing from the tap, though chemicals like bleach are sometimes added in the tank to help the water stay \"clean\". However, when you do that, the water is most certainly not potable.", "Because it is much much easier to just use fresh water than it is to drain everything into a gray water tank, separate major contaminates from that water, install pumps to bring that water to the toilet, and you would still need to hook up fresh water to it as a back up in case you run out of gray water. Water isn't so scarce that installing all that would be worth saving 3 gallons per day.", "In addition, to other answers I'd like to point out, for most people in the country potable water is in near infinite supply. Almost the entire midwest have massive water tables underground, that on top of modern water reclamation facilities means generally speaking none of us have to worry about running out of drinking water. I'm sure a lot of us remember commercials telling us to turn off the faucet while brushing our teeth and so on. These ads were mostly for people in places with more limited water supplies like California or Arizon. (Mostly California as that's where the commercials were made) I personally have well water that is pumped out of a well that has been going strong since 1909, the water starts only about 8 feet below ground and goes on for at least 30 feet. It's connected to the same water table as pretty much every local municipality water supply, dam, and lake within 30 miles. If I want to leave every tap in the house on while I read War And Peace it doesn't matter. It's all going to go out into my septic tank, through the fingers and gets reabsorbed by the water table.", "I had a grey water system for toilet for about 10 years. Not my house... This is only sink and shower water. The bowl was uncleanable. Nasty. We finally removed the system and replaced the toilets. It's ok for gardening if you watch what you run down the drain...", "You'd have to build a separate plumbing system for toilets, incurring additional expense and complexity within the walls.", "Grey water still stinks. You want your bathroom constantly smelling like sewage?", "I once worked at a very environmentally conscious company. When we built a new office, we decided to use grey water for the toilets and for the lawn sprinklers. The \"grey water\" was basically rainwater that was collected and stored in a large underground cistern. The system was relatively simple to design and while it certainly cost more than a regular plumbing system, it was not outrageous. The real obstacle to our proposed system was the county permitting agencies. They were strongly against the use of grey water in any indoor plumbing use. We explained again and again that the grey water was only going to be used in toilets, so what's the big deal? Eventually, we won out with a small compromise. We could use grey water for the toilets, but we had to hang a sign prominently above each toilet that said \"Non potable water. Do not drink!\".", "In order to use non-potable water in our toilets it would require plumbing our houses and cities with an entire separate set of pipes for the other water source and to ensure they can never mix by accident. This is a large cost when we could just clean some more water instead.", "Avalon, on Catalina Island (off the coast of Los Angeles), uses briny water for its toilets. The city uses a desalination plant to create its fresh water. To reduce production costs, the whole city has 2 supply networks: one for fresh water, and one for a briny mix of fresh and salt water.", "There is already some good answers but here is my take on it: Grey water need to come from somewhere. If it is from your own house then you still need some filter to remove some dirt and contaminant, plus kill the bacteria and virus that would grow in that water. Plus it would require a tank and a pump and extra space and extra piping. You could have a toilet-sink combo. I have seen them, but they are expensive and you would use more water than what is used by the sink, so would need to complement it with mostly clean water anyway... Then you could collect rain water, which still need to be filtered and all... Next is the city provided grey water. This would be great, except that you need to double the water infrastructure, double the maintenance, double everything including the leaks! The leaks can be a significant amount. Montreal for example lose I think about 30% of the water via the leaks. Double the infrastructure and you now leak 60% of the total water distributed! And why you need to treat the grey water? There is the odour of course, but as I said, bacteria and viruses. You take a dump, it splash back, and now you have some unknown bacteria and virus on you. You flush and there is always some water that splash, releasing some virus and bacteria in the air. You would need to kill all that, and remove it so the left over do not feed on the dead bacteria and the bacteria population come back as it was. You would still need to put lots of chemicals to keep it low, which is some extra cost... Finally, even in the best case, it would cost the same or more to provide the grey water. In reality it would just cost quite more money. Then we could go to the environemental side of this. With clean water only, the dirty water from the lake/river become almost pure, then used, then refiltered and released cleaner than what the grey water would be. If you have grey water, it would also have to be filtered that much, so it basically transfer the filtering at the sewer treatment plant instead of the drink water plant...", "Plumber here, this would be a terrible idea. The idea of grey water being used as toilet water is simply unsanitary. It would be highly unsafe to have 1.6 gallons of bacteria filled water releasing germs and could spread disease. Most of the country has no problem in terms of fresh water shortage. Even California seems to be doing better in that regard. Try it yourself. Shit in your toilet and leave it there and you'll find your answer quickly.", "We actually did this in Afghanistan. We what to recycle all of our water over there, so they would use whitewater for showers, sinks and laundry, then they used grey water for toilets, cleaning and spraying the roads to keep the dust from kicking up. Blackwater was recycled and made back into whitewater. I think. Drinking water was separate. It's a lot easier to implement when there's no physical infrastructure.", "Where I live, we have plenty of water, so we don't need an entire second system of water supply and collection. My region extracts approximately 4/10 of one percent of the available groundwater. There literally isn't a need for it. Ever time I bring up the fact that I live in a place with a super abundance of constantly renewed ground water, and that there isn't a need for water saving where I live,I get down voted. I can't help That I live in an area with plenty of water. It is a fact.", "Because then we would need another entire system to bring dirty water in for your toilet. As it is, a building only needs clean water in, dirty water out. This is easy to design. Otherwise, you'd need clean water in, dirty water in, dirty water out, and the dirty water in would need to be totally separate to avoid contamination. Also grey water can carry lots of diseases and animals drink out of the toilet all the time.", "Because it would be extremely expensive to run a second set of pipes to every house and building to use for toilets. You would also have to have a second sewer system that only handled grey water instead of black water (sewage) that supplied the water for this new system.", "Infrastructure and taking potable water for granted are the primary reasons, as everyone has already pointed out. Secondly, grey water does offer some degree of risk if not handled properly. There's a fair amount of material that you wash down the drain and might not want in a reservoir in your house. Think pathogens, parasites, fecal material, chemicals. No, you're not going to drink that toilet water, but having pool in your bathroom offers some risk (especially risky in hot climates/seasons and with infrequent use). Having a grey water system requires some serious behavioral changes to be done properly, and not wanting to change habits is a big deterrent.", "I was just thinking about this the other day. I was a an event and had to used the restroom. When I went to use the urinal, there was a gigantic sign in front of it that read \"THIS STADIUM USES RECYCLED WATER. DO NOT DRINK FROM URINAL\". In all caps like that. So does this mean some stuff in america is allowed to use this type of system?", "As a plumber, reading this OP and a lot of the replies was extremely stressful. That sink/toilet thing is stupid and impractical. Septic tanks dont send your poop into a leech field. The tank holds the solids and they need to be pumped out. Toilet bowls hold water to keep sewer gas from coming up through the toilet and stinking up your house. This is also why all sinks and floor drains have traps on them. I have been in thousands of houses and it is more of a surprise to see a clean toilet, rather than a dirty one. Bathrooms are disgusting as it is, so why add untreated, dirty sink water or whatever gray water could be, into that mess.", "Many european countries do that, too. We do use clean 'drinkable' water for toilets in Germany", "Because daddy is lazy and mommy thinks it's icky. (It's mechanically and financially more feasible for construction and maintenance, it is crystal clear and doesn't smell (aesthetics), and generally we've had plenty so we haven't been incentivized towards conservation)", "My former condo in Victoria, BC had its own treatment plant, and the whole thing was purposely-built to high environmental standards. URL_0 Somewhat ironic since the City of Victoria has exactly zero sewage treatment, and it pumps millions of gallons of raw sewage into the Strait of Georgia every day.", "I mean I would guess one of the reasons is so that our pets and children wouldn't get poisoned from drinking toilet water.", "The whole theory behind \"grey water\" toilets seems silly to me. Once the water leaves the toilet and goes to a processing plant the water eventually gets treated and returned to the ecosystem. Once water goes down the drain it isnt simply gone forever.", "Clean drinkable water isn't seen as a luxury in the US. We find it laughable that someone would put water in a bottle and charge $1 for it. We expect it to be free at restaurants and spend little time on conservation of it. It's considered a \"right\" rather than a resource, so we don't spend extra money or time trying to conserve it.", "My grandmother's house used water collected from rainfall. The house was probably built in the 50's in rural Kansas. There was a holding tank dug into the ground near the house that all the gutters fed into. That water was pumped to the house for the toilets. Grandma was a young child during the depression. I never knew her to let anything go to waste. Not even the rainwater.", "at least in the western US, the prior appropriation system makes it very hard to legally use grey water. \"return flow makes the river go\" CU Boulder had to fight for years to even use our grey water system half the time it was designed to run. Denver Water is giving everyone else the middle finger right now, and is using black and grey water in their new headquarters. Grey water is also an expensive retro fit. As a hydrologist, I hope to see more grey water use in the future. We spend a lot of money treating water", "Some commercial buildings do this. It's probably not economical for most homes though, you'd have to catch the water used in the sink, hold it in a tank, then pump it back up to dedicated toilet only lines. It also really depends on where you live. If you live in the Great Lakes region, then there is basically no such thing as wasting water, since the water comes out of the lake, you use it, and it goes back in. The cost of treatment (monetary and environmental) isn't very high. On the other hand, if you were in say the outskirts of Pahrump or Amargosa NV, that might be a different story.", "Because where do we get unclean, unpotable water in our plumbing system?", "Tldr: it would cost too much money in a country with a relatively cheap and large supply of fresh water.", "Because if its not, you would have infectious and dangerous pathogens sitting in a bowl of water in your house that actually aerosols outwards when flushed, spreading infectious mis and spray through the entire house. People would become very sick, and there are some places that use \"gray\" water but they tend to reek of high hell and have some infectious materials in them as well.", "While a lot do, some buildings don't use them. In places like San Francisco, where water scarcity is becoming an imminent problem, building codes are requiring that grey water / process water be used in municipal buildings. San Francisco is even going so far such that buildings over a certain size (I think 250k square feet) must even (or soon will need to) recycle black water. That's sewage, folks, and they're pioneering solutions to reuse that water in a healthy way. We take it for granted; however, some areas are recognizing that we may not have clean water access in the future, especially after natural disasters, and they are preparing themselves.", "At least in the Midwest, water is so cheap and accessible, that it doesn't really make sense to install a new system. Additionally, the water in the Midwest is pretty much a closed system in that much of the water never leaves the Great Lakes or the tributary rivers. What a lot of people forget is that the Midwest was once a giant swamp. It got drained a couple hundred years ago, but there are still massive ditches that run next to every road. When it rains even the slightest bit, those ditches (6-12ft deep) fill right up, and the ground oozes water because it is already soaked from the water table 1 foot below the surface.", "tldr:because that would be stupid and pointless. ______________________ cause thats whats already piped into your house. clean in, dirty out. (besides, the whole \"wasted water\" thing is silly nonsense outside 3rd world or some smallish islands. water treatment is really cheap, running a whole second set of pipes through the house is not. and that clean water isn't going to be sent far away to places that need it anyway(far more cost effective to set up new treatment plants there than ship water out, nobody does that.)) also, grey water *isn't clean*. you don't want that stuff sitting around in your house. (unless you're real selective about the source standing grey water=smell/fumes in the air + corrosive chemicals and sentiment building up in the pipes. you'd almost want to build a whole new treatment plant to halfass purifying it) (edit- and the realistic environmental impact is negligible anyway too) ______________________________________ edit- change \"fist world countries\" to \"at the very least the entire continental united states and canada\" since allegedly some traditionally first world nations still have trouble with an maintaining adequate supply of clean water ;) (just messing with you australia) but op specified america anyway so the answer still works for the question asked.", "Is this an American thing? I thought every first world country used potable water in toilets", "Because greywater *stinks*, really bad, and you don't want a stench like that sitting in your toilet bowl.", "Maybe the costs of using clean water are cheaper than the costs involved with having a second line to houses for \"Grey water\".", "Honestly if the people who built/maintained my apartments tried to manage two separate *incoming* water systems, I would have died of dysentery already.", "We have excess clean water in the us and using one water type(clean water) for all appliances means cheaper plumbing and less complications.", "Just America? I've never seen a country where the water from the toilet was different from the one coming out of the faucet.... And I've traveled around the world...", "The bigger question is why do American toliets have so much water in them? I always freak im goin to tea bag it and/or get splash back. Its just so excessively full compared to NZ", "Basically because putting in all of the pipes to source water from somewhere besides the wastewater treatment plant or to use water that isn't as clean as the water from the wastewater treatment plant would be too expensive.", "Using grey water to flush my toilet sounds primitive and nasty. Who wants nasty doo doo water splashing their ass cheeks every time they drop a deuce? Or when it pops back up and hits your cornhole. Why would i want to replace that experience with grey water? Wtf?", "In the US clean water is cheaper than piping a second water supply or buying systems to reuse water. It's one of those things that might pay itself off over a life time for personal plumbing or several generations for city infrastructure, but people are not willing to take on the cost when they may never see the benefit.", "The amount of water used in toilets is a drop in the bucket of our total water consumption. This, coupled with the fact that the water cycle in North America regenerates quickly means that it doesn't really matter. In the grand scheme of things, the water you use at home has no real effect. (except specific areas and/or drought)", "Here in Australia new houses need to use tank water or other grey water for flushing the toilet and watering the garden. There is even a water recycling scheme in Western Sydney: URL_0 The main issue with using grey water to water the garden is that salt levels build up from the washing powder. Also tank water sucks for washing clothes. URL_1", "When I was in the US Army in South VietNam, we used non-potable water for showering. I suppose we used it for flushing too, but I don't remember being told that. (We may not have even had flush toilets.) This wasn't my regular duty station, but where I was temporarily housed while I was being processed out to go to the big hospital in Japan.", "I worked on an island where we had separate potable water and grey water (mostly captured rainwater) systems so I know it is feasible, but the answer is pretty simple. Throughout most the U.S. we already have a potable water infrastructure, and although fresh water is in short supply in some areas, it is still cheaper then installing an entire separate secondary system for grey water.", "It would take Water companies billions of dollars to build an entire gray water system just for flushing your toilet. it would cost a lot of money for homeowners because they will need to adjust their already built pipings to the new system. It's not so bad. At least we're not draining our waste into rivers like they do in 3rd world countries. I've seen it first hand and it's sad.", "Fresh water is cheap, and plentiful. Even here in the desert of Utah, residential use of water makes up only a small fraction of total water use, with the vast majority going to agriculture and another 5-10% or so going to water lawns. Every 5 gallons of fresh water costs me $0.01 on my water bill. My toilets are the low 1 gallon flushes. So I'll happily pay the $1 to $2 a month for toilet water opposed to the maintenance costs of running dirty water instead.", "The simplest reason is cost, it is much much cheaper to just run one line to house and use the same water for drinking and cooking as you do for bathing and flushing, running a separate system just wouldn't be cost effective A better option would be to capture run off from baths and showers in the house into a holding tank then use this to flush but the work to install this kind of system yet again involves alot of upfront cost and takes years to recuperate, It is along the same reasons as why more people do not have solar panels, upfront cost is too high and savings take too long to pay back the outlay", "It's because it's more economical to have only one line of water coming into a building. An entire network for grey water means additional complexities for not a whole lot of utility. See, in societies, we have this tendency to add complexity to deal with problems. Poop near your house a problem? Let's make a sewer. It's too far to walk to get some fresh water? Let's make a water system. Want to have electricity to provide all the utility that that brings? Let's add power network. But each of these systems has a build cost, and a maintenance cost. So now, we want to add a new water line, but this water is non-potable. So now we need identifiers for each line, that needs to very diligently documented (imagine the disaster if a plumber mistakenly hooks the grey line to your fridge water line, that will NEVER be purged, even if you don't drink any). Additionally, these people need new training, new manuals and new techniques need to be implemented (often just modifications of old procedures and techniques). You also need to have a pump system to push this grey water to your house, you need a source of grey water, which will mean have a multi-step purification system externally. (Think of the steps as: White Usage, First Treatment Step, Grey Usage, Second (Final) Treatment Step, Return to White, cycle) and this system would require ANOTHER sewer system to separate the grey waste to be turned white from the white waste to be turned grey. All this to poo in dirty water. Do you want to pay MORE for water? As much as pooping in dirty water makes *intrinsic sense*, it's really for the best that we use the fresh water. If you truly want to poo in dirty water, as /u/tezoatlipoca stated,you can simply get Sink-To-Toilet systems, but these are really expensive to buy and implement. Most standard bathrooms will have a hard time fitting these systems with the counters, showers, and toilets, without having a major rework of the bathroom."], "text_urls": [[], [], [], [], ["https://www.linkedin.com/today/author/0_1HsHuOdieP1FuoUB6BjpxA?trk=prof-sm"], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], ["http://www.docksidegreen.com/sustainability/environment/"], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], ["https://www.sydneywater.com.au/web/groups/publicwebcontent/documents/document/zgrf/mdq2/~edisp/dd_046179.pdf", "http://www.sydneywater.com.au/SW/your-home/using-water-wisely/greywater-reuse/index.htm"], [], [], [], [], [], []], "score": [10223, 2601, 1473, 855, 501, 183, 173, 151, 150, 101, 84, 81, 69, 42, 39, 38, 33, 30, 23, 21, 19, 15, 15, 10, 10, 6, 6, 6, 5, 5, 5, 5, 5, 5, 4, 4, 4, 4, 4, 4, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3]}}, {"q_id": "6s9at7", "category": "Repost", "title": "Why is pleading 'not guilty' not considered lying to the court?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlb01v2", "dlb0538", "dlb0bmc", "dlb051e", "dlb1rnn", "dlb06wt"], "text": ["Entering a plea is a procedural matter, not an evidentiary or substantial one. Pleading not guilty merely triggers the prosecution's obligation to make its case and prove all essential elements of the offence(s) beyond a reasonable doubt.", "Logically it can't be considered perjury because the Fifth Amendment prevents the state from compelling you to incriminate yourself. For the legal system to function, they have to be able to compel you to enter a plea. Also, you aren't under oath when you plead. Theoretically you would be guilty of perjury if you took the stand and said \"I didn't do it\" (which happens less often than courtroom dramas would have you believe) but if you've already been found guilty the court has better things to do than try people who are already being punished.", "Perjury only applies to testimony given under oath. Every person has the right not to incriminate themselves, and as such a court cannot order a defendant to answer such a question. When the court asks an accused to enter a plea, they are not ordering them to give testimony under oath. As such, when the court is asking to enter a plea, there is no perjury risk attached to the answer. In the American legal system, criminal defendants are presumed innocent until proven guilty beyond a reasonable doubt. The state has the burden to prove to a jury that the defendant is in fact guilty beyond a reasonable doubt. The defendant doesn't have to lift a finger in his or her own defense; unless the state presents sufficient evidence meeting that standard, the defendant must be acquitted. Therefore, when the defendant enters a plea of \"not guilty\", they are asserting their right to be presumed innocent unless and until the state can prove otherwise.", "Perjury is lying while giving sworn testimony. Pleading Not Guilty is a demand for the Governmemt to prove what they accuse you of doing.", "You are not pleading innocent. You are pleading not guilty. It's actually a very different thing. Also perjury is only a thing when you KNOWINGLY misrepresent to the court. So if you believe you have a defense, it's not perjury.", "because, in america you are \"not guilty\" until proven beyond a reasonable doubt to be guilty, and they have to prove you are guilty before you are guilty. so its not lieing. you also have rights to not to incriminate yourself and the ability to face your accuser in court. there is a process, and step one of the process is to plea not guilty. thats why."], "text_urls": [[], [], [], [], [], []], "score": [34, 23, 9, 8, 7, 3]}}, {"q_id": "6s9jya", "category": "Repost", "title": "What are sin, cos and tan?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlb2tm7"], "text": ["Draw a circle with a radius of one inch. If you draw a right triangle inside the circle at some angle, the Sine (sin) of that angle is the length of the vertical line, and the Cosine (cos) of that angle is the length of the horizontal line. The Tangent (tan) of that angle is just the Sine divided by the Cosine. URL_0"], "text_urls": [["http://imgur.com/jvzRYnC"]], "score": [7]}}, {"q_id": "6sd2xd", "category": "Repost", "title": "Why does x^0 = 1? Similarly why does 0! (Zero factorial) = 1?", "title_urls": {"url": []}, "selftext": "I know that they equal to 1, but why, what's the logic here? Something I've always wondered; that my teacher's never answered.", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlbrp2o", "dlc8t2u", "dlbt677", "dlbrxpf", "dlbt6z7", "dlbrqxv", "dlbvu1a", "dld3v2s"], "text": ["When you multiply two numbers together with the same base, you add their exponents to find the answer. 2^3 times 2^2 equals 2^5 or 8 times 4 equals 32 e.g. x^0 * x^2 = x^(0+2) = x^2 = 1*x^2 so in the way that this was constructed, choosing x^0 = 1 makes the rule consistent when dealing with x^0 There is similar reasoning for the subtracting powers rule when dividing. n! can be used to compute how many permutations of n items there are. that is, how many lists of n items where order matters. e.g. you have an orange and an apple. You can arrange it to be {orange, apple} or {apple, orange} 2! = 2*1 = 2 If you only no items, there's only one way to order it. The empty set { } so from the viewpoint of using factorial to compute permutations 0! = 1 is a good choice. There's probably other uses of factorial that I'm not aware of where 0! might be chosen to be something else so that it is consistent with that usage", "Yer not alone in askin', and kind strangers have explained: 1. [ELI5: how do we know x^0 is 1? How did we figure this out? ]( URL_1 ) 1. [ELI5: Why does 0! (zero factorial) equal 1? ]( URL_0 ) 1. [ELI5: Why is 0! 1 and not 0? ]( URL_3 ) 1. [ELI5: Why is \"x^0= 1\"? ]( URL_5 ) 1. [ELI5: Why x to the power of 0 = 1? ]( URL_2 ) 1. [ELI5: Why is x^0=1 ? ]( URL_4 )", "If you understand that: x^1 = x and x^(-1) = 1/x (as long as x is not zero) then you should understand that x^(1)\\*x^(-1) = x\\*1/x but x^(1)\\*x^(-1) = x^0 and x\\*1/x = 1", "Answer to your first question is simple: I think you'll understand this: x/x = 1 now, if you say: x^2 / x ^2 This can be re-written to xx/xx or you go this way: x^2\u20132 which then ends up being x^0 0! = 1 is just defined this way, since it is the only value that makes sense.", "The same reasoning holds for both of these, and it's the same sort of reasoning that leads to x\\*0 = 0. One of the nice properties about addition (and multiplication) is that the order you add things up in doesn't matter. If you want to find the sum of the list [1, 5, 3, 2, 7], you could add up the first three elements (1+5+3=9) and then add the last two (2+7 = 9) and then add those results together (9+9=18), or you could add up the first two elements (1+5=6) and the last three elements (3+2+7=12) before adding *those* together (6+12=18) and you'll get the same result. We'd like this property to hold for *any* way of splitting [1, 5, 3, 2, 7] into smaller lists. For example, we'd like to be able to say that the sum over [1] plus the sum over [5, 3, 2, 7] is also 18, and since we know the sum over [5, 3, 2, 7] is 5+3+2+7 = 17, it must be the case that the sum over the single element [1] is just 1, as we might expect. But what if we split it up in an even more extreme way? What if we put *zero* elements in the first part of the sum and all five in the second? Then we'd have \"the sum over [] plus the sum over [1, 5, 3, 2, 7] is 18\". But we already know the sum over [1, 5, 3, 2, 7] is 18, so the \"empty sum\" of zero objects must be 0. And it doesn't matter what the other elements in the list are - the empty sum will always end up being 0 through the same logic. If we define multiplication as repeated addition, we have x\\*2 representing the sum over [x, x], x\\*3 representing the sum over [x, x, x], and so on. In particular, x\\*0 is the sum over [] and is therefore 0. So x\\*0 \"should be\" zero, if we want our definition of multiplication to be natural. The exact same reasoning works with products, but with 1 as the value of the empty product. If the product over [2, 4, 3, 2] is 2\\*4\\*3\\*2 = 48, then we not only want the product over [2,4] times the product over [3,2] to equal 48 (which it does, since 8\\*6 = 48), but also the product over [] times the product over [2, 4, 3, 2] to equal 48, which implies the product over [] is 1. Then x^n is the product over [x, x, ..., x] with n copies of x, so that x^0 is the \"empty product\" and therefore 1. Similarly, n! is equal to the product over [n, n-1, ..., 2, 1], which is the empty product when n is 0.", "In regards to your second question, it's mainly for the sake of continuing the sequence. 4! = 1 x 2 x 3 x 4 = 24 We can then divide that by the greatest number to get 3!, And so on and so forth. 4!/4 = 3!, 3!/3 = 2!, 2!/2 = 1! Since 1! is just 1, dividing it by the greatest/only number still leaves you with 1 Does that make sense?", "The answer is that we want x^0 and 0! to conform to certain generalizations that work for numbers other than 0. For x^0, we want the equation x^a /x^b =x^(a-b) to work when a=b just as well as it does when they are not equal. Obviously x^a /x^a =1, so x^(a-a)=x^0 must also be equal to 1. In the case of factorials, it's to make combinatorial formulas work better. For instance, there are n!/b!(n-b)! ways to choose b objects from n objects if b < n and b > 0. If we define 0!=1, the expression also works for b=n and b=0.", "X^a divided by x^b always equals x^a-b. Also, X^a / X^a always equals one (any number divided by itself is one). If X^a /x^a =1, then X^a-a must be equal to one. X^a-a is X^0 , so X^0 =1. For 0!, I always thought of it as an artifact of n!/(n-1)! =n. This makes sense- 5!/4! = (5x4x3x2x1)/(4x3x2x1), which clearly is just 5. Therefore, 1!/0! Must be equal to one, and if 1! Is also equal to one, in order for 1/0! =1 to be true, 0! =1"], "text_urls": [[], ["https://www.reddit.com/r/explainlikeimfive/comments/3w07ac/eli5_why_does_0_zero_factorial_equal_1/", "https://www.reddit.com/r/explainlikeimfive/comments/5v8ef4/eli5_how_do_we_know_x0_is_1_how_did_we_figure/", "https://www.reddit.com/r/explainlikeimfive/comments/3ickmp/eli5_why_x_to_the_power_of_0_1/", "https://www.reddit.com/r/explainlikeimfive/comments/5gc0v3/eli5_why_is_0_1_and_not_0/", "https://www.reddit.com/r/explainlikeimfive/comments/j8wmr/eli5_why_is_x01/", "https://www.reddit.com/r/explainlikeimfive/comments/6ofw7a/eli5_why_is_0_1/"], [], [], [], [], [], []], "score": [271, 24, 16, 10, 7, 6, 4, 3]}}, {"q_id": "6sd79t", "category": "Repost", "title": "Why is South Korea so dominant in eSports?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlbt5pc", "dlbt7qo"], "text": ["When i first started playing League of Legends, I got interested in the competitive scene. Don't play as much anymore but still follow the scene. Koreans dominate in LoL simply because they take their practice more seriously. They individually play the game for longer hours than the players from teams of other countries they face. The teams are run more efficiently with coaches, psychologists, etc. and team practice and the formation of chemistry is more focused on. Eventually it becomes a cycle where the best competition is in Korea and so if you aren't playing in Korea, you aren't facing top tier competition so you won't improve as much as people playing in Korea. Sort of like if you want to be the best football player ever, if you aren't playing in Europe, you don't have a chance. Teams from other countries try to imitate, but they are lagging behind in infrastructure and overall attitude of practising and \"tryharding\" to improve.", "South korea has a culture around eSports like America and football, or most of the world and soccer. Matches are held in arenas with large audiences just like physical sports here. There are college courses dedicated to eSports, and it is treated as a profession. Competitors will spend more time practicing their game of choice than westerners spend at work, upwards of 12 hours per day."], "text_urls": [[], []], "score": [6, 3]}}, {"q_id": "6se6x9", "category": "Repost", "title": "How does a conductor conduct music by waving a stick around?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlc0tum"], "text": ["The basic gist of it is that the conductor keeps time. The conductor moves their baton in such a way that it comes in contact with an imaginary surface (the ictus) on each beat. The movements are repeating over the course of a measure, so for 4/4 time the conductor will repeat a motion of 4 beats. The conductor further adds in their own emphasis to be interpreted by the musicians in the orchestra. Such as large intense movements to emphasize that a certain part of the piece will be very loud and thundering, or gesturing towards certain instrument sections. This is all within the context of the piece being played, which most orchestras will have practiced together multiple times. The conductor isn't communicating WHAT to play, but instead ensuring that the entire orchestra is in sync."], "text_urls": [[]], "score": [4]}}, {"q_id": "6sfgu4", "category": "Repost", "title": "how does the fourth dimension work? And what does it mean?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlcboqq", "dlcc0y0", "dlccb9d"], "text": ["Mostly, people refer to time as being the fourth dimension. It's a different concept than the other three, but the basic idea is the same: how much information do you need in order to uniquely identify an event? You can specify any location with three dimensions: say, latitude, longitude, and altitude. But if we're meeting for dinner, that won't be enough. You'll need a time to actually get there.", "You live in a 4 dimensional universe. Three dimensions are distance (spacial) and one is time (temporal). The speed of light (C) is the ratio of the distance in the temporal one, the one we call time, to the distance in the spacial ones, which we call distance. Every object exists as a unit velocity segment in this 4-space. Since a 4-space is hard to think about, let's simplify (ELI5!) by considering the spacial dimensions in terms of our motion. Now we only have one spacial dimension, the direction we are moving. Turning (for the time being) doesn't count. Next we graph our 2-space universe, with time on the vertical and distance on the horizontal. Every object is one unit from the origin on this graph, a quarter-circle. If a segment is aligned with the time direction (it's vertical), the object's spacial dimensions must be 0, this gives 0 speed in space and 1 second per second in time. If the velocity segment is oriented along the spacial dimension (horizontal) the object is moving at C, and since all segments are one unit long, it must be 0 in the temporal dimension. Thus photons move at the speed of light but do not experience changes in time. Gravity and other forces use energy to change the orientation of an object's velocity segment, accelerating it in space and shortening the time element or decelerating it in space and lengthening the time segment.", "URL_0 Here's a video of Carl Sagan explaining it. He does a great job of dumbing it down and showing clear visuals. Hope it answers your question"], "text_urls": [[], [], ["https://youtu.be/N0WjV6MmCyM"]], "score": [31, 18, 11]}}, {"q_id": "6sfjg0", "category": "Repost", "title": "Why do some words feel like they aren't words anymore when you say/write them a lot?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlccnxd"], "text": ["It's called semantic satiation. Basically when you repeat a word enough your brain will just interpret it as white noise URL_0"], "text_urls": [["https://en.m.wikipedia.org/wiki/Semantic_satiation"]], "score": [13]}}, {"q_id": "6sfjym", "category": "Repost", "title": "Why is mint the go to flavor for toothpaste, mouthwash, etc?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlccmom", "dlcdmig", "dlcccij", "dlcdik7", "dlcd562", "dlcilhg"], "text": ["When toothpaste was first introduced most people didn't use it regularly like we do today because they either forgot about it or didn't notice if they missed a brushing here or there. When companies started making mint toothpaste, people started to notice if they didn't brush their teeth because the tingly feeling after brushing was associated with a clean mouth. The habit that developed made mint toothpaste the best selling kind by far, and it continues to this day.", "Japanese toothpaste and medicine sometimes tastes like root beer and they generally don't like to drink root beer because it reminds them of it.", "Because mint is very good at masking the smell of bad breath.", "Sorry that i can't answer or ELI5, hope this post is still allowed. But if you go to the pet store you can get toothpaste in peanut butter, banana, beef, bacon, and a few other flavors.", "My kids (ages 1.5 and 3.5) toothpaste is different flavors like orange, bubblegum, etc...and I think they taste awful. Not sure when mint comes into the equation, when they get a bit older I'd imagine. Perhaps the flavor is too strong for many young palettes? Idk. Interesting question though...sometimes standards maintain for CPG, other times they evolve from marketing campaigns to capture the desired demographic.", "The aroma of the herb activates the salivary glands in our mouth Improving the health of a person\u2019s mouth is a well-known benefit of mint. Since it has germicidal qualities and quickly freshens breath, it adds to oral health by inhibiting harmful bacterial growth inside the mouth and by cleaning the tongue and teeth. This is why, mint used to be rubbed directly on the teeth and gums to refresh the mouth and eliminate dangerous forms of growth. In modern times, for the same reason, mint is one of the most common elements in toothpaste, mouthwashes, and other dental hygiene products. Of course, the easiest way to get these results is to simply chew on the leaves. URL_0"], "text_urls": [[], [], [], [], [], ["https://www.google.com/amp/s/www.organicfacts.net/health-benefits/herbs-and-spices/health-benefits-of-mint.html%3fisamp=1"]], "score": [182, 53, 42, 13, 4, 3]}}, {"q_id": "6sfoq3", "category": "Repost", "title": "Why did we decide that certain words were \"bad\" and shouldn't be used in social settings?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlcdl8u"], "text": ["There is an excellent podcast by Stuff You Should Know that is entirely about swear/curse words. They explain the history, psychology and science of curse and swear words, which are actually two different things."], "text_urls": [[]], "score": [3]}}, {"q_id": "6sj97d", "category": "Repost", "title": "How does a record work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dld8j8g"], "text": ["Sounds are waves. A guitar string produces waves by vibrating the air. Changes in sound occurs when these waves differ in frequency. Vinyl records work by creating sound waves with small scratches on its surface. When the surface is \"scanned\", a small reader moves along the contours of the scratches that exist in the disc. This creates vibrations in the point, which is transfered into an amplifier that produces sounds. The vibrations vary as the point reads a different scratch mark, which creates the different sound wave."], "text_urls": [[]], "score": [3]}}, {"q_id": "6sjqom", "category": "Repost", "title": "why are USA using imperial system rather than the international system?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dldc84v"], "text": ["We were established as a country before Metric was invented, we spent most of our history being highly self reliant, and until WWII we were fairly Isolationist. After WWII we spent several decades as the industrial power of the world providing the materials Europe and others needed to rebuild. It only became reasonable for us to switch in the last few decades, and by this point in time so much of our infrastructure would have to be changed that it is not feasible. And as you point out we are very independent and so any foreign entity that pressures the US to change something will be met with extreme resistance by the populace."], "text_urls": [[]], "score": [3]}}, {"q_id": "6sk3q8", "category": "Repost", "title": "How come some words lose their meaning when repeatedly saying them out loud or reading them?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlddzxb"], "text": ["[Semantic Satiation]( URL_0 ) > The explanation for the phenomenon is that, in the cortex, verbal repetition repeatedly arouses a specific neural pattern that corresponds to the meaning of the word. Rapid repetition makes both the peripheral sensorimotor activity and central neural activation fire repeatedly. This is known to cause reactive inhibition, hence a reduction in the intensity of the activity with each repetition. Jakobovits James (1962) calls this conclusion the beginning of \"experimental neurosemantics\". Stolen from Wiki...and probably using words bigger than suitable for a five year old (sorry)."], "text_urls": [["https://en.wikipedia.org/wiki/Semantic_satiation"]], "score": [3]}}, {"q_id": "6sk9ue", "category": "Repost", "title": "Why do we not like listening to our own voices in a recording or video but are perfectly fine listening to them as we talk?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dldehc4"], "text": ["You're used to the sound you usually hear when you talk. However, this is not how you actually sound. Your actual voice is higher than what you hear due to the sound passing through your head. Since you rarely ever hear yourself recorded, you naturally have an aversion to it. If you got used to hearing your recorded voice, you wouldn't hate it as much."], "text_urls": [[]], "score": [4]}}, {"q_id": "6skgg1", "category": "Repost", "title": "How headphones can create auditory illusion of hearing from behind despite the fact that the sound only comes from left and right ?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dldfkp2"], "text": ["The same way you do with only two ears. Time lag, wave length and tone - all these factors play important parts for the brain when determining the direction of sound. In the following description, they are treated under separate headings, but when a person registers a sound, all three factors interact, helping to determine the direction from which the sound originates."], "text_urls": [[]], "score": [12]}}, {"q_id": "6skosl", "category": "Repost", "title": "Outside of academia, who employs modern philosophers and what is their role in modern society?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dldhx22", "dldxxlj", "dlducuc", "dldxyzy", "dldgbdg"], "text": ["I'm sure some more will come to mind soon, but the first one I thought of: Ethicists. When a company or corporation needs to go through an ethics committee, those people are philosophers. Similarly, before doing any experiments (e.g. in science) you also need to get ethics clearance. Ethics is a big domain of philosophy. Edited to add: Also, I know this is kinda covered by \"academia\", but the main thing that philosophers do is write papers for publication. Whether it's in ethics, metaphysics, aesthetics, philosophy of science, stuff about personal identity or time travel or whatever. Philosophers are the ones researching and writing about it! (Source: am married to a philosopher).", "**Copy-pasting my response to this question from a previous [ELI5] ( URL_0 )** > Let me start with this: my undergrad is Philosophy. > Today: Lets make a distinction between Philosophers - people who DO philosophy for a living - and philosophy students - people who use the general tenets gained by in-depth study of philosophy in their day-to-day jobs. Philosophers, those who do, tend to be employed in very limited fields, traditionally academia. These are university professors and authors. They make their money by teaching others philosophy in classes and through media (books, videos, whatever). I fall into the latter category. I use my background in philosophy in the workplace. This is what typically happens if someone does their undergrad in philosophy and gets a decent job. I \"sell\" skills like inductive and deductive reasoning, rational inquiry, the interpretation of complex material into simple terms, and excellent oral and written communication into a position I am interested in (I work in organizational development). Because I sell these things, plus experience, I can get a job that provides. That is how I, and many others, make money from philosophy. By no stretch of the imagination are we Philosophers (other than the shade-tree sort). But, if you are interested in pursuing the degree, know that it is possible to live (in the US, pretty well) if you market it well. Many use philosophy to pursue advanced degrees or positions in Law (my friend Joy), Economics ( my friend Sara), Business (my buddy Nate), or Industrial and Organizational Psychology (me and two others from my grad school cohort). > I will always remember the opening words in my freshmen \"Intro to Philosophy\" text: Philosophia non panem torrit. Philosophy bakes no bread. Philosophers, today and throughout history make very little from doing actual philosophy and very much from applying to something whether it be teaching others, solving complex problems, or maintaining an organization.", "Two that haven't been mentioned: Computer science - Computers are, at the basic level, logic machines. Logic is one of the four original branches of philosophy. The best computer programmers use careful logical reasoning to solve problems in the most efficient way possible, then convert that reasoning into logic-based coding. Aristotle would've been proud. Judge/lawyer - Law and philosophy have a close relationship, and philosophy is one of the most common pre-law school majors. In many ways law is basically applied ethics and political/social philosphy.", "Like a lot of social sciences, Philosophers are surprisingly flexible in terms of employability. Stuff like HR departments or PR employ all kinds of professionals, lecturer at a publisher, editors of newspapers, journalists all can and will occasionally employ Philosophers (or people with a degree in philosophy to be precise) If you have a degree in philosophy you are well trained in logic, ethics and in the work with text based sources of any kind. You could even work in a SIGNIT department of a intelligence service.", "I'd say lots of them write books and/or articles and essays which they sell to magazines or even get invited to tv talk shows to discuss things. A philosopher or public intellectual can also rely on making a show of his/her own on youtube and monetize on that. But I think books and generally written stuff is the main source of income. Which ones do you have in mind?"], "text_urls": [[], ["https://www.reddit.com/r/explainlikeimfive/comments/5q99r6/eli5_how_do_philosophers_make_money_how_did_they/"], [], [], []], "score": [17, 11, 7, 4, 3]}}, {"q_id": "6slgp2", "category": "Repost", "title": "Why does the United States have so many military facilities on foreign soil, while other 'superpowers' do not?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dldmycm", "dle0ah5", "dldls46", "dldmdzd", "dldqf54", "dldmpd3"], "text": ["What other superpowers? It's those very bases you speak of that makes the US a superpower in the first place. Most militaries are structured defensively. They primarily exist to protect a country's borders. That's necessary when you exist along side many other countries. What good does a base on the other side of the world do when all you are charged with is protecting your own border? The US has no such borders to worry about. They won't be invaded by Mexico or Canada any time soon I promise. A large number of troops stationed in the States would be a total waste. Unlike almost all other militaries, the US is an OFFENSIVE military. They are charged with bringing power to wherever the party is. You can't do that without bases. Currently the US (and UK) has one of only 2 Blue-water navies on the planet. The reality of it is, for better or for worse depending on where you stand, the US is the world police and (if you are a NATO member) the \"world\" protector. In order to be the world police, you gotta have bases everywhere.", "Late to this party. As others have mentioned it, there are no other superpowers in the world currently. Having the ability to project power overseas is a big part of why the US is a superpower, and others are merely major powers or regional powers. Also, the policy of the US having facilities on foreign soil comes out of WW2. In fact, in General Marshall's [*Biennial Reports of the Chief of Staff of the United States Army to the Secretary of War: 1 July 1939 - 30 June 1945*]( URL_2 ) (official URL_7 link), Marshall writes on 1 September 1945, the topic of future defense/security policy: > The German armies swept over Europe at the very moment we sought to avoid war by assuring ourselves that there could be no war. The security of the United States of America was saved by sea distances, by Allies, and by the errors of a prepared enemy. For probably the last time in the history of warfare those ocean distances were a vital factor in our defense. We may elect again to depend on others and thee whim and error of potential enemies, but if we do we will be carrying the treasure and freedom of this great Nation in a paper bag. He then writes: > Even as late as 1940 I was asked very much the same question before a committee of Congress. Not even then could I say definitely exactly where we might have to fight, but I did recall that in past wars the United States forces had fought in Latin America, in France, in Belgium, in Germany, in Russia, in Siberia, in Africa, in the Philippines, and in China, but I did not anticipate that in the near future American soldiers would fight in the heat of Burma and in the islands of the vast Pacific, and would be garrisoning areas across the entire land and water masses of the earth. From this lesson there is no alternative but that this Nation must be prepared to defend its interest against any nation or combination of nations which might sometime feel powerful enough to attempt the settlement of political arguments or gain resources or territory by force of arms. And then: > At the close of the German war in Europe they were just on the outer fringes of the range of fire from an enemy in Europe. Goering stated after his capture that it was a certainty the eastern American cities would have been under rocket bombardment had Germany remained undefeated for two more years. The first attacks would have started much sooner. The technique of war has brought the United States, its homes and factories into the front line of world conflict. They escaped destructive bombardment in the second World War. They would not in a third. > **It no longer appears practical to continue what we once conceived as hemispheric defense as a satisfactory basis for our security. We are now concerned with the peace of the entire world. And the peace can only be maintained by the strong.** Emphasis mine. This is taken from page 209-211 in the section *For The Common Defense*. As you can see, military thinkers - before Japan even signed the Instrument of Surrender - were already thinking about a new world after WW2 and the necessity for the US to go beyond its isolationist roots and think about defending its interests overseas, far from its shores across the oceans, which were soon to be no longer a viable defense. One poignant part that Marshall brings up too is that the captured German leadership pointed out that by late 1946 or 1947, the East Coast of the US would be in range of future German rockets and bombers. Thus, using the oceans to defend one's own self is no longer viable. I also feel it is important to point out that the bulk of US troops overseas actually are rooted in history as well: [the list of US troops stationed overseas, as illustrated in this graphic by Time]( URL_14 ) shows that for individual nations: * Japan - 48,828 * Germany - 37,704 * South Korea - 27,558 * Italy - 11,697 * Afghanistan - 9,800 Now, Afghanistan is obviously a war zone. But then you see that 3 of the top 4 are the vanquished Axis foes of WW2, all of whom were occupied after the war (and some, like Germany, didn't have their full sovereignty restored until [the end of the Cold War]( URL_8 )). The other one is South Korea, where US troops have been present since the end of WW2, first to occupy south of the 38th Parallel (with the Soviet Union occupying north) after Japan's defeat, and then as part of the US forces of the UN Command to defend South Korea in the Korean War, and then as [part of the Mutual Defense Treaty Between the United States and Republic of Korea]( URL_0 ) signed October 1, 1953. Finally, I want to point out that while no other countries have military bases in the US - there is a considerable presence of foreign troops in the US that most do not realize. For instance, here is the US State Department's Foreign Military Training Joint Report to Congress for 2015-2016: URL_3 This is an annual report with all unclassified data published online for public use. This file lists each of the 80+ nations that the US had training operations conducted with, including a breakdown by location in the US where it was conducted. This list excludes NATO nations, Japan, Australia, and South Korea. In addition, the US has had long term foreign troops stationed in the US. The German Air Force [has been in Holloman Air Force Base, New Mexico]( URL_1 ) (official URL_10 link) since 1992. The German Air Force has been in the US since 1958. The US Air Force also has the Euro-NATO Joint Jet Pilot Training (ENJJPT) program at Sheppard AFB which has been producing jet pilots for the US and 13 other partner nations [since 1981](http://www.sheppard. URL_10 /Library/Fact-Sheets/Display/Article/367537/euro-nato-joint-jet-pilot-training-program-enjjpt/). The Italian Navy sends all of its pilots to the US for training by the US Navy and US Marine Corps. [Embassy link here]( URL_11 ). I would know too - I trained with quite a few of them. How little do people even realize these foreign troops in the US? The US Air Force's 428th Fighter Squadron is in fact a Republic of Singapore Air Force unit [which has been in the US since 2009](http://www.mountainhome. URL_10 /News/Article-Display/Article/665884/peace-carvin-v-singapore-celebrates-5th-anniversary-with-us-air-force/). That unit flies the F-15SG. Yes, tiny Singapore has an Air Force squadron in the US. Correction, it has more than one: the 425th Fighter Squadron is also a Singapore Air Force squadron [which has been at Luke AFB, AZ since 1993]( URL_6 ). They fly the Singaporean version of the F-16. So while these units are renting spaces in existing US bases that still have US commanders, this is quite akin to the arrangement the US has with may other countries like Soto Cano Air Base, which is a *Honduran* air base where the US has a detachment - [Joint Task Force Bravo]( URL_13 ) located. And lastly - other nations DO have military facilities on foreign soil. I'm not entirely sure where people get this idea that other nations don't have troops overseas. China just built its [first overseas base in Djibouti, Africa]( URL_4 ) The UK in November just opened a new base [in Bahrain, called HMS Jufair]( URL_9 ) [France has bases]( URL_5 ) in Djibouti, Senegal, Ivory Coast, Gabon, and the UAE And so on", "There are no other superpowers, first of all. To answer your question: America is isolated from the Europe-Asia-Africa landmass by two large oceans. Over 80% of the world's population lives in Europe, Africa, and Asia, meaning that that's where most geopolitical problems are going to occur. It is difficult to support a military operation from so far away, so America has built bases close to where the action is to solve that problem.", "Well there isn't any other superpowers currently. Other large countries do have military facilities on foreign soil, but not as much as the US. France and the UK have a good amount of military base on foreign soil, mostly in their ex colonies. Russia also have several of them, but those are mostly in ex-soviet country. China have a naval base in Djibouti and since China is on the path to becoming a superpower, it will probably have more and more of those base in the future.", "America has mutual-defense treaty obligations with a number of allied countries. Due to the distant locations of some of those countries, it would be logistically impossible to fulfill those obligations without having the personnel and materiel resources readily available on their soil. Additionally, having those resources in place also serves as a deterrent to any who might threaten that ally.", "There are no other superpowers. There are world powers, but that is a lesser category of influence than a superpower. When the USSR was a superpower they had bases among their allies like the US does currently, but that ended when the USSR fell. Russia in its lower power position still has some, but not nearly as many."], "text_urls": [[], ["http://avalon.law.yale.edu/20th_century/kor001.asp", "http://www.holloman.af.mil/Units/German-Air-Force/", "http://www.history.army.mil/html/books/070/70-57/CMH_Pub_70-57.pdf", "https://www.state.gov/documents/organization/265163.pdf", "https://www.theatlantic.com/news/archive/2017/07/china-djibouti/533385/", "https://en.wikipedia.org/wiki/Overseas_military_bases_of_France", "http://www.luke.af.mil/News/Commentaries/Display/Article/641469/a-premier-alliance-425th-fighter-squadron/", "army.mil", "https://chnm.gmu.edu/1989/archive/files/germany-final-settlement_e0189c0884.pdf", "http://www.telegraph.co.uk/news/2016/11/10/todays-opening-of-the-royal-navys-new-bahrain-base-seriously-enh/", "af.mil", "https://it.usembassy.gov/embassy-consulates/embassy/sections-offices/odc/ite-programs/", "http://www.sheppard.af.mil/Library/Fact-Sheets/Display/Article/367537/euro-nato-joint-jet-pilot-training-program-enjjpt/", "http://www.jtfb.southcom.mil/", "http://time.com/4075458/afghanistan-drawdown-obama-troops/", "http://www.mountainhome.af.mil/News/Article-Display/Article/665884/peace-carvin-v-singapore-celebrates-5th-anniversary-with-us-air-force/"], [], [], [], []], "score": [62, 61, 42, 13, 8, 3]}}, {"q_id": "6srgtt", "category": "Repost", "title": "Triboluminescence?", "title_urls": {"url": []}, "selftext": "After watching a video regarding a Prince Rupert's Drop, the term \"triboluminescence\" was coined as to why there was light created from a bullet striking it. When this term was first discovered in the 1600s, it was referred to with hard candy, and striking it creating sparks. Where do the sparks come from?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlezqcv"], "text": ["It seems to be not completely understood, but the fracturing of the glass produces a charge separation - there are fewer electrons on one side of the fracture than the other. There's then a sharp electric current (flow of electrons) through the gap to equalize the charges, which ionizes the air in between as in a lightning strike, producing the light."], "text_urls": [[]], "score": [3]}}, {"q_id": "6srs3p", "category": "Repost", "title": "Why do prefixes Sept-, Oct-, Nov-, and Dec- mean 7, 8, 9, and 10, but they refer to the 9th, 10th, 11th and 12th months?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlf1h98"], "text": ["Because there used to be only 10 months, not 12 - January and February were added later. Prior to that, the ~60 days between December and March were just 60 days of winter that didn't belong to any month. The year also began in March, not January. And before anyone says it: no, it wasn't July and August that were added. Those were renamed from Quintilis and Sextilis (which follow the same naming scheme as the last 4 months), long after January and February were added."], "text_urls": [[]], "score": [7]}}, {"q_id": "6ssd0o", "category": "Repost", "title": "Why after you chop some onions the smell in your hand lingers for a century while perfumes fade away?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlf5vka", "dlf5v80", "dlfzzhl"], "text": ["IIRC, most perfumes are alcohol based. Alcohol is very volatile, and the majority of it evaporates quickly after leaving the bottle. That's why if you ever talk to someone selling perfume (sometimes you can't help it), they tell you to let the scent mellow for a little bit before you really know what it will smell like. The compound that gives things like onions and garlic their potency is released when you cut into them, and is intended as an irritant. This was to ward off things that would otherwise eat the onion in the original habitats. Side note, these compounds have the ability to destroy the cells of dogs and cats, so should never be fed to them in any form. The compounds released by cutting onions convert their amino acid sulfoxides to sulfenic acid. This what makes you cry, but also what sticks to your hands, and is very difficult to remove with normal washing. Most guides say stainless steel will help to remove the odor, and I've found it usually works for me.", "Because it soaks into your body. Yer not alone in askin', and kind strangers have explained: 1. [ELI5: why do smells like onions and vinegar linger on your fingers no matter how many times you wash your hands? ]( URL_0 ) 1. [ELI5: Why do flavors like garlic and onion stick around in the taste buds so much longer than others? ]( URL_1 ) 1. [ELI5: Why does the smell of onions stay on my hands for a such a long time? ]( URL_2 )", "Not an explanation but advice that might be useful if you are on this thread: You can get rid of most of the smell of onion and garlic from your hands if you wash your hands without rubbing them, just let the water run on your hands for a few seconds. Is doesn't get 100% of the smell but it's better than the usual method."], "text_urls": [[], ["https://www.reddit.com/r/explainlikeimfive/comments/3muwou/eli5_why_do_smells_like_onions_and_vinegar_linger/", "https://www.reddit.com/r/explainlikeimfive/comments/4c3gl1/eli5_why_do_flavors_like_garlic_and_onion_stick/", "https://www.reddit.com/r/explainlikeimfive/comments/395s9s/eli5_why_does_the_smell_of_onions_stay_on_my/"], []], "score": [28, 15, 3]}}, {"q_id": "6stpbq", "category": "Repost", "title": "Why is liquid water so hard to compress", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlfer8w", "dlfen9b"], "text": ["Primarily because it is already really dense. The polar nature of water brings the molecules of water really close together naturally under normal pressure and at that point it is really difficult to get them closer together.", "The molecules are too close together. If you compress water the forces between the molecules stop them getting much closer, so you can't really change the density"], "text_urls": [[], []], "score": [7, 3]}}, {"q_id": "6stput", "category": "Repost", "title": "Why do people's stomach look bloated when they're malnourished?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlfemif", "dlgcihc", "dlfepct", "dlg25fk", "dlg1oe5", "dlg3kej", "dlg72f1", "dlfwa3u", "dlgd55z", "dlg1ib6", "dlgo61s", "dlgobjz"], "text": ["It's called kwashiorkor, and it's a sign of serious protein deficiency. The stomach gets bloated because of fluid retention and because the liver expands with fat deposits. Interestingly enough, kwashiorkor gets its name from what an African tribe called it. Translated, it means \"disease of the deposed child\". What would happen is that when a 2nd child was born, the first child would be abruptly cut off breast milk and put onto a more adult diet high in carbs and low in protein. This resulted in protein deficiency.", "Hey, just wanted to clarify some things. Severe malnourishment has several sequelae (outcomes) depending on what exactly is lacking in the person's diet. The two that most people are familiar with are (1) Kwashiorkor - the kind with the really big belly and (2) Marasmus - The kind where the people look like walking skeletons. In marasmus, there is generalized severe malnourishment. These people are sick because they are lacking sufficient calories, thus they become incredibly skinny - they are literally wasting (actual medical term) away. In Kwasiorkor, there is sufficient/close to sufficient caloric intake, BUT there is INsufficient PROTEIN intake. This means that the diet is mostly rice, corn, etc. Your body needs proteins for countless things such as building muscle etc. It also needs proteins to transport fats (not soluble in blood/water) throughout your blood stream. These 'transport' protein are called lipoproteins and are made in the liver. Without these proteins, the fats consumed by the body get trapped in the liver, leading to fatty livers (contributing to the big bellies). Also, proteins are needed to maintain the proper fluid volumes in your body (I won't get into this now) and without it, you retain water, contributing to fluid retention (medically called edema), and thus also making the bellies bigger. I hope this helped :) (Source: 3rd year US Medical Student - Thanks for letting me review this concept!) EDIT: XD This is the first time i get gold! Thank you guys!!! (I guess med school paid off after all haha)", "That's called *kwashiorkor*, and it happens when there's not enough protein in a person's diet. Protein in the blood keeps water bound in blood, and if there's not enough protein then the water leaks out into the tissues, mostly in the stomach and abdominal area.", "A lot of people are saying its protein deficiency, but if so I'm curious why people in developed countries, for example anorexics, don't typically get bloated stomachs from malnutrition. If it was just protein deficiency wouldn't they get that too?", "Now question to anybody who knows: is having this issue a binary thing? Like you have it or you don't? Or can you have a mild/gradual case of it? I've had friends before who I thought were borderline malnourished and looked incredibly skinny fat or had developing, weird looking stomachs...", "When you're so malnourished your liver can't make a protein called albumin, which is required to keep fluid in your blood vessels. This causes fluid to leave the vessels and enter a cavity like your abdomen. It's the same reason why people with liver cirrhosis get abdominal distension.", "Protein deficiency. Protein in the blood, primarily albumin, is largely responsible for the osmotic force that keeps water in the pressurized vasculature from leaking out. ELI5 version: if you don't eat enough protein, your body can't put the proteins into the blood that keep water in there. The water leaks out into the abdominal cavity, among other places.", "There is also such this as protein sickness, where you have too much of it and not enough other things. This why killing a deer is enough meat to feed you through a winter in the wilderness, but you'll get sick if you do not find other sources of nutrients.", "I was always told that parasites and tapeworms caused this. Glad to finally know the true reason.", "As people have said, protein deficency; leaky blood. Also, parasites in contaminated food or water sources.", "As many had say is because of low protein intake, which leads to low albumin, which leads to a drop in oncotic pressure, which leads to loss of plasma to the tissues (edema), when we talk about the peritoneal cavity is called ascites, thats why people look bloated, they have peritoneal fluid in there, you can document this by doing the fluid wave test or an ultrasound.", "A lot of people already answered regarding lack of protein. This is one of the reasons we send Plumpy Nut to famine hit areas. URL_0"], "text_urls": [[], [], [], [], [], [], [], [], [], [], [], ["https://en.m.wikipedia.org/wiki/Plumpy'nut"]], "score": [4786, 4628, 596, 180, 54, 35, 31, 15, 11, 10, 8, 3]}}, {"q_id": "6suct4", "category": "Repost", "title": "Why do some objects fade their own color under sun?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlfkdqz"], "text": ["The UV rays can break down the chemical pigments that produce color. This results in color fading over time. The reflectivity if the object will impact the absorption of UV light and therefore impact the rate and degree of fading."], "text_urls": [[]], "score": [3]}}, {"q_id": "6svgru", "category": "Repost", "title": "How encryption isn't easy to decrypt", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlfueu4"], "text": ["You are right that there are flaws in some encryption systems that store the key in the same place as the encrypted data. This is like hiding the key to your house under your door mat. This is why most systems will ask you for a password to unlock your encrypted data. The password itself is the encryption key. There is also a problem that if you have access to the encrypted data the key have to be located in RAM. So if some attacker is able to access your RAM he may be able to get the key from there. This was the big issue with the heartbleed bug that allowed a remote attacker to read a random section of the RAM which may contain secret encryption keys. One possible solution to this is to use a Trusted Platform Module which is a separate hardware chip that is able to hold a key but will not hand it out. All encryption and decryption will happen inside the device. Cell phones have had such devices for a long time as the SIM card works like that. Although it is not available for any application."], "text_urls": [[]], "score": [3]}}, {"q_id": "6svvot", "category": "Repost", "title": "If the U.S is in so much debt, how is the American dollar still worth so much ?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlfwz2k", "dlg1kkq", "dlfzxf5"], "text": ["The value of a countries currency has very little to do with it's debt obligations. There are nations with no debt that have currency that is considered worthless to the rest of the world.", "Think about a bank. Technically, every account a bank has is considered a debt. Now ask, why are banks not poor.", "Because there is a lot of American productivity, demand for American goods and services, and the U.S. can easily handle its debts. No different than somebody with a mortgage and car payments totaling 4x their income still having an 800+ credit score."], "text_urls": [[], [], []], "score": [8, 5, 3]}}, {"q_id": "6sxkxv", "category": "Repost", "title": "Why do cans with compressed gases in them feel cold after you spray their contents?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlgbjmy"], "text": ["because it's not simply compressed gases. it's a chemical that's in liquid form when under high pressure. when it's in low pressure, it turns from liquid to gas and extracts heat from its environment. this type of chemical is commonly used for refrigerant."], "text_urls": [[]], "score": [4]}}, {"q_id": "6sxoe9", "category": "Repost", "title": "do bugs and insects feel pain ?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlge2jl", "dlgcsqn"], "text": ["do they squirm when you squeeze them? if so yes.", "Yes. Bug's and insects have a state of consciousness, with nerves, brain, blood, etc. Just like humans and other animals All of these things contribute to feeling pain."], "text_urls": [[], []], "score": [4, 3]}}, {"q_id": "6sy7am", "category": "Repost", "title": "How does an automatic transmission work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlgl5ye", "dlgksnw"], "text": ["Oh man, I dont think I can actually ELI5 it, but ill try. Ok, first things first, the whole point of gears in a car is to convert the very fast but not very \"strong\" rotation of the engines crankshaft, to slower but \"stronger\" rotation of the wheels (basically you need to convert torque). In a manual gear box, you do that by pressing the clutch to disengage engine from wheels, and change gear ratios, literally you move around cogs with different diameters by hand. There are three kinds of auto transmission: 1) double clutch and robotic manuals these essentially use computers to do what you would do by hand by predicting via sensors engine RPM, wheel rotation, driving style etc. 2) CVT (continuously variable transmission) You have to conic shaped gears that are connected via a belt or chain, you slide the chain on the cone diameters to vary gear ratio. 3) Fluid torque converters, you have a casing that contains a viscous fluid and three bladed fans (impeller, turbine, stater). One (impeller) is rotated directly by the engine and thus moves the fluid, the fluid then moves the second fan (turbine) which in turn directs the fluid to the stater (which is a smaller fan) and thus converts torque. Shit does that make sense? p.s. I'm leaving out planetary gears, because they are a part of the fluid converters to provide more gear ratios as well as reverse.", "Traditional planetary geared automatics have hydraulic systems which react to engine speed and load, causing various clutches and bands to disengage and re-engage inside the transmission. It wouldn't be ELI5 if i explained it much further i think. Newer planetary automatics that are controlled electronically , according to wikipedia, \"use sensors on the engine to detect throttle position, vehicle speed, engine speed, engine load, etc. to control the exact shift point.\" Automated manuals like Porsche PDK and nearly every other Dual Clutch Transmission use the same set of information to determine their shift points. These shift points are tuned in such a way that either provides the best fuel economy or the best acceleration, or both if the vehicle has multiple driving modes."], "text_urls": [[], []], "score": [10, 3]}}, {"q_id": "6syx2j", "category": "Repost", "title": "How can people do accurate voice impersonations, if their voices sound deeper to themselves?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlgpfyo", "dlgp5u9", "dlgva4r", "dlgzisl"], "text": ["A lot of impressions have more to do with how someone speaks rather than how they sound. Pay attention to their accent, where they pause, how they emphasize certain words, where they speed up and slow down. Now practice. Record yourself. Review. Repeat.", "Practice, practice, practice. And other people telling you that you sound \"just like so-and-so\". It isn't hard to make sounds that you made before.", "An important part is also the listener's brain approximating if a voice sounds just close enough to the original. Same for coverbands.", "The inner-voice is often distorted to the untrained ear. This is the reason you'll cringe when hearing a voice recording of yourself being played back. A huge step in training your voice to sing or perform voice-overs is to train your ear. This requires hours of recording yourself and listening to it over and over. It won't be exact, but that moment of shock will no longer exist when you hear yourself anymore. So many people who imitate accents are quite used to the way their natural voice actually sounds."], "text_urls": [[], [], [], []], "score": [58, 14, 5, 3]}}, {"q_id": "6szy5b", "category": "Repost", "title": "why do heroin addicts all have the same face?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlgtokk", "dlgwzsn", "dlgtmpx"], "text": ["its the body rotting away, I don't know if you've ever touched a heroin addict, it feels weird. they are (almost) literally bone and skin. Edit: My point is that skeletons are very similar. Source: grandma was a heroin addict.", "I think you're misidentifying crystal meth addicts as heroin addicts - but on the whole, the reason why poor(1) drug addicts look similar is because of malnutrition. It's an uncommon look these days, so it stands out - but if you look at medieval paintings, you'll see a lot of guys that look like meth addicts. Low subcutaneous fat gives a lot of definition to facial features people who are eating normal amounts don't have. (1)- Heroin addicts with jobs tend to just look a bit sweaty, pale, and have slightly out-of-focus eyes.", "I think at first glance our brains focus on the distant eyes, loose jaws and the red/picked faces."], "text_urls": [[], [], []], "score": [12, 6, 3]}}, {"q_id": "6t014s", "category": "Repost", "title": "Why does your heart actually hurt when you're \"heartbroken\"?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlgw7ue", "dlgywph", "dlh0505"], "text": ["If we rule out anxiety from a heartbreaking event (which can and will cause chest pain) the answer is [Takotsubo cardiomyopathy]( URL_0 ), also known as broken heart syndrome. This can also occur when coming good happens and you get too excited (or a heart attack, stroke, arrhythmia from a non cardiomyopathic source, etc.). It causes, among chest pain, acute heart failure, arrhythmias, and rarely ventricle rupture. This syndrome temporarily weakens the heart muscle by thinning the walls of the lower portion of the heart, making it much less efficient. Almost all patients make a full recovery within 2 months of having their hearts literally broken. But to reemphases, when your chest hurts because of heartbreak, it's probably anxiety and not your heart losing the will to live.", "> Terms such as \u201cheartache\u201d and \u201cgut wrenching\u201d are more than mere metaphors: they describe the experience of both physical and emotional pain. When we feel heartache, for example, we are experiencing a blend of emotional stress and the stress-induced sensations in our chest\u2014muscle tightness, increased heart rate, abnormal stomach activity and shortness of breath. In fact, emotional pain involves the same brain regions as physical pain, suggesting the two are inextricably connected. > But how do emotions trigger physical sensations? Scientists do not know, but recently pain researchers uncovered a possible pathway from mind to body. According to a 2009 study from the University of Arizona and the University of Maryland, activity in a brain region that regulates emotional reactions called the anterior cingulate cortex helps to explain how an emotional insult can trigger a biological cascade. During a particularly stressful experience, the anterior cingulate cortex may respond by increasing the activity of the vagus nerve\u2014the nerve that starts in the brain stem and connects to the neck, chest and abdomen. When the vagus nerve is overstimulated, it can cause pain and nausea. [Explained by Robert Emery and Jim Coan, professors of psychology at the University of Virginia.]( URL_0 )", "I made a [short video to answer your question]( URL_0 )! However, if you dont want to watch the video, I'll type my answer here too. * Becoming heartbroken involves a lot of emotional stress. Emotional stress has been linked to having negative physical effects on our body too. Our muscles tighten, we have shortness of breath and our heart rate increases. * All types of pain come from our brain, it's essentially a collection of chemicals. * When we are in relationships we recieve opiods which are our bodies version of morphine. They are addictive, and seen as a pain killer and make us feel good. * Once the relationship has ended we enter withdrawl, which has been known to cause heart problems and pain in the heart. * In 2009 a study showed how the area in our brain that deals with emotional pain can stimulate a nerve in our brain stem. This nerve is connected to our chest and neck and abdomen. If overstimulated it causes physical pain and nausea. Hope you have a great day, and I hope you enjoyed the joke at the end of the video!"], "text_urls": [["https://en.wikipedia.org/wiki/Takotsubo_cardiomyopathy"], ["https://www.scientificamerican.com/article/what-causes-chest-pains/"], ["https://www.youtube.com/watch?v=QO46dMaIRGs&amp;feature=youtu.be"]], "score": [36, 8, 3]}}, {"q_id": "6t04d5", "category": "Repost", "title": "how does chirality work if there are no absolute directions?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlguxys"], "text": ["Molecules with *chirality* are asymmetrical in some way. The details differ greatly since molecules are incredibly diverse. There are a variety of components that exist in 3d space that can be arranged, flipped, twisted, or curved in different ways. Many molecules are simple enough that they do not have alternatives, but molecules can contain dozens or even hundreds of atoms. A good example would be two gloves. No matter how you rotate or flip a left-handed glove it will never be a right-handed glove"], "text_urls": [[]], "score": [5]}}, {"q_id": "6t0dbl", "category": "Repost", "title": "is Gluten really bad for the body?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlgyy57"], "text": ["It is bad for coeliacs. Their bodies think elements of gluten are bad and tries to remove them from the body. This removal takes a toll the intestines, and they can't absorb nutrients from food due to this damage. So they avoid gluten as best they can. [Source]( URL_0 )"], "text_urls": [["http://www.nhs.uk/conditions/Coeliac-disease/Pages/Introduction.aspx"]], "score": [6]}}, {"q_id": "6t0gak", "category": "Repost", "title": "What happens to the tiny bugs who fly into your eye?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlgz7f0", "dlh24rj", "dlh21et", "dlh2zlc", "dlh2d78"], "text": ["Depends how tiny. I would say most of them get caught in your eye fluid and either cleaned out in the corner of your eye, or, with a larger but not huge (think mosquito sized) buy like I copped, it gets stuck under an eyelid and causes irritation until you dig it out with a cotton bud the next morning.", "What happens to the ones that fly up your nose though? :/", "I have been getting a lot of bugs flying into my eyes lately. Most slightly smaller than mosquitos. It's the worst though! I was wondering earlier, is it a southern thing to have this many flying insects or is it a problem everywhere?", "Most times your eyelashes bat them away. Sometimes if you're really unlucky they go under your eyelid and you have to dig them out. Related story below:", "I used to think they got stuck in there forever, but then I realized I just have eye floaters."], "text_urls": [[], [], [], [], []], "score": [52, 29, 9, 7, 5]}}, {"q_id": "6t0ls3", "category": "Repost", "title": "How did it become common place for humans to call their parents \"mom\" and \"dad\" as opposed to their actual name?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlgyd04", "dlh4yfn", "dlgy7a5", "dlh6hsb", "dlh8200", "dlh9yee", "dlhk73e", "dlh5pkn", "dlhhk24", "dlh78u5", "dlh9cbn", "dlh8xpg", "dlh4abp", "dlh9260", "dlh4mtq", "dlhoqtv", "dlhmcer", "dlh9y67", "dlhl5ag"], "text": ["My linguistics Professor told us that even in completely unrelated languages, their early words to address the parents tend to gravitate towards a certain type of sound. Her explanation was that the lip muscles are one of the earliest muscles the child learns to use, because sucking is important for survival, so bilabial open syllables (open syllable are simple consonant+vowel combination) like \"ma\" \"ba\" or \"pa\" are the easist for a child to learn. \"mom\" and \"dad\" would then be the slightly more grown up version of \"mama\" and \"dada\". (da is a bit of an odd one out because it's not bilabial, but still relatively easy to learn compared to complex words) Even in languages in which parents are traditionally addressed more formally, they usually start out with easier \"baby\" words, and adopt the more formal terms later when the child can speak properly. But in many cases, some variation of the babyterms just stick. In short: a baby physically wouldn't be able to address his father as \"Alexander Leopold von Gro\u00dfauchenbach\", so they just call him \"dada\" instead.", "We all know how addressing people works differently in different dialects of English. (mom, mum, ma, mother to name a few) most of these forms are based on language acquisition. Children go through different phases where they start using open syllables (think mah , moo, da) then later they start using repetition (mama, dada, moomoo). Nasal M is \"easier\" to learn (one of the first sounds to make) because it's a constant flow of air through the vocal cords (voiced) then out the nose. Pronouncing the p or d (which are considered plosives) requires better coordination of muscle groups since the airflow has to actually be stopped for their realization. m is easier to learn than p. addressing people, especially specifically defined people groups such as: coworkers, bosses, servants, family members, clerics etc. is incredibly complex and a fascinating part of linguistics. There are other languages where it's commonplace to refer to parents by their first name, or as already mentioned in other comments: japanese people refer to their siblings when it comes to a direct address with the japanese word for \"sister\". other languages are way more interesting than English when it comes to the direct address of people, or family members. this ain't no ELI5, but for anyone interested in that topic i suggest starting to read about the concept of politeness and language, esp. Brown & Levinson \"Politeness: Some Universals in Language Usage\" the basic breakdown of how you address someone is very complex. Brown and Levinson postulate that humans have two distinct \"faces\". A positive face and a negative face. The positive face is something like: I want to feel great and mighty and powerful. The negative face is I want to keep the stuff I have and not have anyone threaten me or my position. Positive face politeness is saying how great the other person is. Negative face politeness is saying how little of a person oneself is to make the other person appear bigger/greater than oneself in comparison. How does that work in real life tho? Well if you look at french for example, they have the \"tu\" and \"vous\" for the english \"you\" singular and plural respectively. This so called T-V-Distinction can be found in other romance languages like spanish for example. If you used \"tu\" with some total stranger or a police officer or a person that is usually respected, that's considered rather impolite and offensive. You're (according to Brown & Levinson) \"threatening\" their positive face by not adhering to societal standards in paying respect to their position in society. English only has the \"you\", but think about old english \"thou\". You've seen it in bible texts and in religious contexts mostly. Only a few centuries ago the thou got replaced by you. The politeness towards people like parents and immediate family members, which used to be addressed with a \"thou\" (informal, less social distance) got reinterpreted and children started to \"you\"(more formal, more social distance, but also respect) the parents to show more politeness and practiced the positive face politeness. This was in no way the children's choice obviously. Funnily enough we find examples of people wanting to use a different way of expressing the lacking concept of plurality when it comes to the word \"you\" in English. The lack of distinction gives rise to words such as \"y'all\" or \"yous\". I could go on and on. Such a fascinating part of language < 3 feel free to ask more **EDIT:** \"thou\" is informal and more direct, which was a deliberate choice for the church at the time. 'God and his representations (priests, clerics, bible etc.) are so close and involved in society'. It was a kind of marketing scheme in that way.", "Ma, pa, and da are the first sounds that babies tend to make. Most languages have some variation of these syllables for their parents.", "My Sociology of Cognition professor gave some lectures on totemism and how people across cultures dedicate special titles as a collective to people they look up to, whether it's a community leader of some sort or a person within the family depending on the pecking order. Mom is mom, Uncle Joe isn't just Joe but mixing uncle and Joe is ok because not as high up on the respect order as the parent. Kids raised by grandparents might call the grandmother mama since they play that roll. All societies have pecking orders and status symbols, etc. It helps us cognitively sort the world around us. Where this originated I'm not sure, but the idea he was relaying is that we all, as collectives in society and as individuals, need to make sense of the social order around us by sorting people with signs of status and respect. We say \"hey doc\" to doctors but we don't call them by first name, generally. We say \"professor\" rather than just their name, maybe \"professor (last name)\". Some adjuncts are ok with \"professor (first name)\" but my Sociology of Knowledge professor earned her PhD mid-semester and people started calling her \"professor (last name)\". There's no society out there without these designations of status, and it makes sense. Obviously mom has a higher status in one's life than the mailman, no offense to the mailman. I don't know of any society where it's acceptable or normal across the board to call mom and dad by their first names only, but I might be wrong. Social sciences are fuzzy and my area of focus is more on current dynamics because I'm also studying public policy and political science but that's what I've gathered so far. Hope this sorta maybe answers the question along with the other gems in this thread. There's no one exact answer I think, because even cognitive sociology is theoretical rather than full blown empirical, compared to say, chemistry and whatnot.", "People are addressing a question of ontogenetics, i.e. why it's easier for individuals to say \"mom\" and \"dad\" earlier than arbitrary names. But OP's question is actually a different question: (s)he's wondering why this became cemented even later in life. In other words, OP is asking a question about why we stick with those words *instead of* actual names. I'd actually like to question an assumption in OP's question, which is that \"actual names\" for individual persons (that they kept throughout their life) predated words for \"mom\" and \"dad\". It's much more likely that humans had \"words\" (or conventionalized noises) for referring to or getting the attention of their caregivers long before we had conventionalized names.", "I was actually looking into this just yesterday! The answer is that what you call your parents, siblings, and what we consider extended family differs incredibly from culture to culture. There's a whole segment of anthropology devoted to Kinship systems. Concepts such as descent lines, lineage, consanguinity (people you're blood related to), affinity (people who marry into family), and kinship that is tied to neither blood or affinity are different across many cultures. Most kinship systems have words/ titles for parents, but they vary greatly. In some kinship systems, you call your father dad, but also all his brothers are also dad (same with mother and her sisters). In some cultures, every person of a certain generation in your family is dad. In some, your father's brother's son is your brother, but your father's sister's son is your uncle. In some aboriginal tribes, the words cycle through generations, so your great-grandmother is called your daughter. The titles can be honorific, but mostly are used as a label to show your place and role in a society/family. In western society, Dad and Mom take care of Son and Daughter. The relationship between Dad and Son is different than the one between Uncle and Nephew, and Grandfather and Grandson, but those rules aren't ubiquitous across all cultures. In more stratified societies, even more divisions exist to qualify your relationships and place in the family. For example, in Sudanese culture there are 8 different words for cousin based on their relation to you in the family. If I understand it correctly, in some aboriginal tribes everyone is considered family and there are strict rules about which moms can marry which dads, and if you interact with a certain tribe a lot they might assign you a mom or dad type (skin names) depending on if they see you as part of their society. To answer the original question, we call them different names to signify their place in the family unit, but what family units look like vary incredibly across all cultures. How the culture evolves and understands the family dictates the actual words used and what they mean. Finally, in Western Culture we continue to use these titles in place of names as a sign of respect, but that isn't a given across all cultures.", "When I was a wee lad, I thought your name would automatically change into mom/dad once you got children. Also, a baby would come out through a bellybutton. It was a simpler time.", "It has to do with linguistics and dates back to the origin of language. Mama and papa are two of the simplest sounds that humans can utter and and that's why it's almost always a baby's first words. They can make the sounds just by pushing air out their mouth and opening/closing their lips. That's why you see such similar words for mom/dad in other languages (especially ones that originated from Proto-Indo European regions). When humans first developed the capability to speak, it's postulated that names of objects were assigned based on natural phenomenon i.e. to reference a dog you would make a barking noise, to reference the wind you would make a whistle, and to reference one's mother and father you would use the name that babies intrinsically address them as using their relatively incoherent babbling-mama and papa. Hope this helped!", "Apologizes for this being long. The new born\u2019s brain is basically a blank slate, like a brand new CPU without any software, so they have to learn how to verbally identify who and what is Mom or Dad before they can use the vocal cords to say words correctly (it\u2019s not just mimicking words: the infant has to learn to identify what words means and what reactions they get from parents when learning to speak in order to know if they\u2019ve identified the right word for the right person.) They also have to practice and learn how to control their body while trying to use the muscles for verbalizing words with brand new vocal muscles beyond just basic crying and cooing to gets parents attention. Look at it this way: Just as infants practice walking by hanging onto objects and cruising along the edge of furniture while standing, they do this by learning how to balance their bodies on their own two feet before trying to take steps on their own; Infants also practice using their voices to make words in the same way. Babies \u201ctalk\u201d to us all the time (only we don\u2019t recognize the efforts until the words are very clear,) The infant makes words and as parents we eventually react to the word. I laughed a bit at other kids when voices were cracking as they grew up. How many times have you seen a video of a baby trying to talk that mom or Dad recorded, but the sounds re highly indistinct\u2026 but both parent swear is very clear? While the Mom speaks she may use the chosen word for Dad and the more times the Mom spends during her time talking about Dad, the sooner she is going to recognize when the infant is actually saying the chosen word for dad correctly... The more often the infant is acknowledged by attempts to make the correct word the sooner the infant actually uses this word loud and proudly. It was a shock for me when I distinctly heard my child correctly say \u201cmomma \u201d and it was imprinted on me for life! Even though I could hear my child using the word for me in his babble while crying and I knew when he was just practicing making sounds. It takes a lot of effort to make word sounds with their inexperienced newborn vocal muscles (even though the infant has heard the language often enough while still in uterus to know it\u2019s own parents language and can differentiate it\u2019s parents dialect shortly after birth The part of the brain responsible for coordinating the two halves of the brain is the corpus collosum. The ability to use right brain (creativity and imagination) and left brain (logic) simultaneously may well have been what made Einstein a genius. Each child is basically a genius in the respect of learning how to speak compared to lower mammals \u2026 learning to speak requires the active integration of both sides of the human brain be focused to make a sound as speech and memorize word meanings. The corpus callosum contains highly packed bundles of neural fibers which are found in humans and other high order mammals (apes) and allows the two hemispheres to talk to one another. The infant has these bundles of nerve tissue in place by 34 weeks of gestation and it is interacting and both sides are coordinating activity while the infant is still in the womb. It is thought that dreaming and use of memory is what is required to trigger conscious awareness to control language in the infant, yet the infant has been practicing verbal sounds since birth - usually while also practicing body control (turning he head, moving hands, etc.) I swore I could hear my unborn infants trying to talk to me while I rested in bed in the evenings and it was quiet, but I learned later that scientist did \u201cvideo recorded ultrasounds of fetuses during the third trimester, where they startled the baby with a low-decibel noise against the mother's abdomen and caused the fetuses to display traditional crying behavior, such as opening their mouths, depressing their tongues, and gasping irregularly. So yes, infants do practice speech and crying while in the womb and that was probably what I heard. The verbal control and constant verbal practice from babies (which we as adults tend to ignore) is called babble. My sons spent their \u2018free time\u201d babbling constantly, as well as constantly listening. My sons both said \u201cdaddy\u201d months before they ever said \u201cmommy.\u201d and this was because I was at home speaking to them more often than their father had time to. But from the adults as the infant continues to practice word sounds more frequently some adults get annoyed and we find we are now telling the infant to \u201cshut up.\u201d Humans are the only species who tend to juvenalize our pets as well as our own children for as long as possible. My sons are my sons their entire lives. My two dogs are trained to respond to me as \"Mom\" and at times i swear I can hear them saying \"mom\" to me. (my sons don't hear it, but i do!) My dogs remain juveniles as long as they remain my pets - they get babied and treated as young babies, though both are seniors now they are my babies. And we humans demand our children respect us by calling us Mom or Dad when speaking to us (I would have been backhanded as a child if I ever tried to call my parents by their real names - though I fully knew their names by the time I was at least 3 years old.) The use of name substitutions is part of human culture. I identified my aunts and uncles by using the words as part of their titles \"Aunt Suzy and Uncle John.\" I had to learn to introduce my parents to others by their title as well 'These are my parent, my Mom \"Mrs. Joan Survivor\" and my Dad MR. Victor Survivor.\" Don't forget, since we keep our children juveniles all their lives, we insist of being called by our genetic titles all of their lives as well (representing my love for my parents - nobody else in this entire world ismy Mom or my Dad. I'm not a Catholic so would never call a priest as 'father.' Hell, I even Capitalicize the words in writing to honor my parents because I'm so socially indoctrinated.", "The reason parents sometimes call their kids \"son\" or \"daughter\" is because we get the names mixed up. > Come here, Robert, Benson, James, Maximus, whoever, you, get over here! We've all done that, right? I remember I was trying to call the name of a kid who was working for me once at a BSA camp and I cycled through the names of the seven other staff members in my area (who were all kids) before hitting his name. It's incredibly useful to just have one word that can refer to all of your kids, or maybe all the kids of one gender or whatever. And so we return the favor by calling our parents by the loving epithet of mom or dad or papa or whatever. And so the cycle continues, generation after generation.", "The sound \\ma/ is the easiest sound for human beings to make, and occurs I every recognized language on the planet. Being that early humans spent the majority of their time with female caretakers, the sound\\ma/ was quickly associated with these females. The second simplest sound in language is \\pa/. Linguistics is very interesting if questions like these are on your mind.", "First sounds children can make. Ahhhhh. Close mouth and hum. Mmmmmm. Close mouth, then open. Maaaaa. Ma. Ma ma. Common in many languages including Sino-Tibetan family.", "As others have said, the sound \"ma\" or \"mamamama\" is related to the baby's need to feed and therefore the mother's breasts. This is also where the root for mammals and mammaries comes from... it's all related as far as I understand it. Makes sense that the baby saying \"feed me\" ie \"mamama\" becomes the word for mother. The real question is where does \"DAD\" come from! lol", "I think it goes way, way back before written history. What many do not know or maybe realize is that people lived in groups, without individual dwellings. They knew whether knowingly or unknowingly that sex lead to children and that certain traits were passed from 'father' to 'son' even if that was a 'spiritual' trait. Women used to have sex with the hunters, and the best hunter was usually the busiest man, and he also was usually the guy who didn't live the longest. Because of this trend, women who got pregnant would pick from a group of men to be their 'partner', those who either didn't hunt or weren't that great at it, but they were good at other things. This was also good for the group, as it promoted less aggression from the males and it gave the women help in taking care of the young children. And there were a lot of young children, as many did not make it to adulthood. This became the family unit. I would imagine that ma and da were a way for the child to identify their parents, and validate it as a family group. It would probably also be easier to say, depending on whether or not they had given each other names at that point. This would seem to be the logical choice of defining family, as children would take care of parents, when the parents could no longer provide. And, when moving as a family, you couldn't accidentally take another person's child, as the child would know who their ma and da was very early on. And you could easily ask even a very young lost child who their ma or da was and they could point them out. I think it was such an easy and logical way to define family that it was passed on through generations and cultures, until today. And, even today we tend to define the roles even further by birth parent and parent.", "They are titles used for respect. Brother and sister are not used in the same way as they are one's peers. The respect thing also includes Aunt and Uncle, but not cousin, again, because cousins are one's peers.", "My neighbors had two children about two years apart from each other. When they thought they were doing well with teaching the oldest how to speak, it reverted back to babbling with their younger child and the two created their own language.", "when we're children, we make noises. adults have perceived those sounds as \"pa\" for dads, \"ma\" for moms, and \"ba\" for food/bottles - which has to do with the psychology of humans and how i ears perceive. so, partly, babies name their parents \"ma\" or \"pa\" and partly, adults feel rewarded by the sounds babies naturally make.", "Just food for thoughts~ Mom and dad is basically a title just like Commissar, Vice president, Chief, etc. Its used to define your relationship to one another on a social level and to place yourselves as pieces on the social board game. By determining who is mom and dad (even if not biologically being mom and dad) you determine your relationship to one another socially and emotionally, and as such it serves to create a bond between you.", "The question has a problem. It assumes that there was a time were we would call our parents by their names. Both names, and the way we call our parents, go back a long long time. AFAIK there isn't a clear way of knowing if one came first or not. It makes sense that we wouldn't need names for our immediate family. When I talk about my mom or my dad I am talking about a specific person. When I talk about my uncle, or my niece, it's harder to map who I am talking about specifically. Still when we are born we only care about our parents, and so only need to name them, not by their real name, but something easier. Babies are really bad at speaking, they're just learning, and so can only form very simple sounds. The first sounds they make are things like \"gah\" or \"ba\" or \"da\" or \"o\" or \"meh\" etc. Parents want their kids to quickly learn to call for them, so they give themselves simple names that can easily be formed by the simple sounds, but won't be accidental: \"dada\", \"mama\", \"patah\", \"nana\", \"babo\", \"naan\", \"tatah\", etc. This are different ways of saying mom or dad in different languages. As we grow we still call our parents the same way, why would it change? Most people only deal with one mom and dad during their childhood. So we just keep calling them like that."], "text_urls": [[], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], []], "score": [11722, 1364, 253, 72, 61, 13, 12, 11, 11, 10, 6, 5, 5, 5, 3, 3, 3, 3, 3]}}, {"q_id": "6t0mut", "category": "Repost", "title": "How are medicines discovered?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlgz3zp"], "text": ["Medications work by initiating a physiological response in the body. It is not possible for any chemical to make the body react in a way the body is not capable of reacting in to begin with. So, to find a medication to treat a disease or symptom, scientists must: 1) figure out what is causing it 2) figure out what body processes can address it 3) find a chemical compounds that can initiate that process on the body with minimal side effects 4) figure out the best method of delivery to get the correct dose to the correct part of the body It is a long, complex and expensive endeavor (new drugs take 10+ years and upwards of $5 billion from start to finish) Its basically trying to reverse engineer a key for a complex lock."], "text_urls": [[]], "score": [4]}}, {"q_id": "6t0y72", "category": "Repost", "title": "Bayesian probability in very simple terms?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlh1lh1"], "text": ["Bayesian and frequentist are ways of *interpreting* probabilities. A frequentist probability is a relative frequency. In other words, the frequentist probability of some event occurring is the fraction of times in which it would occur, in the limit where the number of trials goes to infinity. A Bayesian probability is a subjective \"degree of belief\". It depends on your prior knowledge, hence why it's subjective."], "text_urls": [[]], "score": [4]}}, {"q_id": "6t3cek", "category": "Repost", "title": "How does global debt even work, and how do nations pay off their debts?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlhllk2"], "text": ["Government debt exists as bonds. Bonds have a fixed payment schedule, they pay interest over their life and their face value at maturity. A nation pays back it's debt by following the payback schedule In the US the vast majority of the debt is held by private citizens with most of that existing in retirement funds. If your parents have bonds in their 401k then they own US debt A nation never needs to get out of the red, as long as they've been paying on time they can just issue more bonds to cover the now due bonds so they're only out the interest. Inflation also cuts into the real effect of the interest, if interest is 3% but inflation is 2% then they're only out 1% of the total debt which is very manageable. If that debt leads to 2% growth they're ahead by a lot You also don't want the US to get out of the red. It would slow down all government projects due to funds being unavailable, and crash the global market due to a sudden lack of safe bonds to invest in, all in all very bad"], "text_urls": [[]], "score": [6]}}, {"q_id": "6t4mrq", "category": "Repost", "title": "how do baby chicks not imprint on each other?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlhvjj5"], "text": ["They only focus on animals much larger than themselves. It is genetic. They look for moving creatures much larger than themselves. In nature, if it is not mom, they are a meal anyway."], "text_urls": [[]], "score": [4]}}, {"q_id": "6t809j", "category": "Repost", "title": "Why can we capture images of celestial objects which millions of lightyears away but not capture detailed images of Uranus or Neptune?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlilzf1"], "text": ["We're taking some fabulous new photos of Jupiter, but only because there's a fabulous new space probe *at* Jupiter. (Juno). When a similar mission orbits Uranus & Neptune we'll get some new images. Our current images of Neptune (Voyager 2 flew by in 1989) & Uranus are from brief flybys from probes on thier way out We **can** take pictures of Neptune from orbit of Earth (such as the Hubble). Here is how the Hubble sees Neptune: URL_0 not a great image, is it? Well here's why images of Neptune & Uranus are so junk: They're not very bright. Taking an image of a local planet is hard because thy do not make light, they are far from the Sun so they do not reflect much light, and they're moving faster (relative to Earth's own movement) than something much farther away. A distant star or galaxy **is it's own light source**, are waaaay bigger than any planet, and don't wiggle as much during the image exposure."], "text_urls": [["https://upload.wikimedia.org/wikipedia/commons/6/63/Neptune-visible.jpg"]], "score": [9]}}, {"q_id": "6t82ae", "category": "Repost", "title": "How do graveyards make money or sustain themselves after they are full?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlisq6k"], "text": ["It's pretty complicated and gross. Graves are turned over in some countries. After around 100 years, grave sites lower caskets and bury new bodies over them. In some countries rights are perpetual. URL_0"], "text_urls": [["http://www.straightdope.com/columns/read/2248/do-cemetery-plots-have-expiration-dates"]], "score": [3]}}, {"q_id": "6t9m2g", "category": "Repost", "title": "What causes time to move forward?", "title_urls": {"url": []}, "selftext": "Im reading this book called The Physics of Time by Richard A. Muller, (highly recommend reading) and he states that time moves forward because our current entropy state is so highly improbable. Can someone eli5 this for me?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlj0mhd", "dlj0w30", "dliyzwg", "dljj536"], "text": ["Thank you for this question, this is really one of my most favourite aspects of physics: Let me start with the Big Thing, please stay with me: Time does not exist as actual dimension. Time is an illusion of \"stuff happening in the physical world\". Imagine yourself to be in a room where no outer stimulus comes in. No light from a window, no sound from the other side of the door. Now, there is also nothing in the room itself that changes, no water tap with dripping drops, no breeze from a ventilator, no dust settling, no nothing. How could you tell that \"time\" passes? You feel your own heartbeat, you feel your breathing. If you wait long enough you feel the need to eat, to drink, to sleep, to go to the toilet. If you wait long enough your nails and hair grow. But let us assume for some reason you do not have to, you just sit there and... sit there. How could you tell \"time\" passes? You cannot - unless you move your hand. Unless you get up. Unless you take an object and let it drop so it falls down. Now you suddenly can tell *something happend*. A moment ago you were sitting on the chair, now you stand. The physical space has changed and there are two states, one before you got up and one after. If you let something drop you create a whole lot of differing physical states in space: you have a thing in the hand, it drops, it drops further, it drops faster and faster and faster... and it hits the ground and rolls under the bed. By observing what happens in the physical space you can tell a passage of what we now call \"time\". You can also tell that \"the time it took you to move your hand was shorter than the time it took you to walk through the room\", this means you somehow start to quantize a new observable beyond mere \"where is an object in the space I am in\" in the universe: time. Our observation of time is very unprecise. Everyone knows that \"time flies if you have fun\" and stretches and strechtes if you are bored - on the other hand in our memory the day where we had lots of fun and did a lot of thing was much longer than the one we just waited out. To remedy this we build machines that repeat the same movement in space as precise as we can. A pendulum swings. A water drop dripping down from a defined opening (i.e. a water clock). A spring is wound up and makes some axis turn which moves a digit. We then count the repetitions and say \"Ok, 60 of those is a minute, and 60 of those is an hour\" or similar. The most simple clock is the sun, we say \"If it is right above and then again, we call it a *day*\". If a season repeats because earth fully turned around the sun we call it a *year*. So far so simple. We get the impression time exists because \"stuff\" happens around in the universe - and that includes our cells that grow and die and finally we grow and die as that is just chemical (fundamentally physical) proceedings in space. Now for entropy: --- In the most simple approach entropy is a measurement of \"Order in the Universe\". In very broad strokes: The higher the entropy the less ordered is the universe, meaning there are more states. A piece of wood has a lower entropy than the burned piece of wood. Now, in physical space things only happen *on their own* where the entropy is increased. So a ball falling down happens on its own because it increases the entropy. You have \"ordered\" energy in the form a ball lying on a table. If it falls down it loses that energy by disturbing all the air molecules it falls through, it hits the floor and makes all those molecules in it vibrate, the ordered energy from the ball on the table is now very, very unordered all over the room and this means: the entropy in the room has increased from state 1 (ball on table) to the new state (ball has fallen down). We call this \"Energy is scattered all over the place and thus entropy increases\" as \"time moves forward\". Because, on their own, balls do not fall up back on the table, cells do not \"undie\", a set of fallen deck of cards does not order itself again. Because that would require the entropy in the room to decrease again and the room taking a \"more ordered state\" (meaning the cards are not lying all over the place but are nicely on a stack, possibly in a specific order, i.e. all colors together etc). I wrote that entropy does not decrease on its own but you very much could go around and pick up the ball or the cards again, you might even order them again and put them back on the table. So you cheated entropy? You restored the highly ordered state of energy again? Yes, indeed, you did. But by that you increased the entropy in the room due to moving around, calling energy from your muscles and turning them into heat that now is in the room. You ordered the system of \"ball and table\", but the *total* entropy in the room (universe) went up - and as such you can tell that \"time has passed forward between state 1 (deck of scards scattered) and state 2 (deck of cards neatly on the table)\". Now one thing missing from your question: Muller writes about \"improbable\". Imagine the room has a billion billion billion possible states where the ball is on the floor, the air molecules it shoved aside are scattered, the molecules in the floor have swung and all the ball's energy has dissipated as heat and increased the entropy. Of course (yes, of course!) there is the hypthetical case where all the molecules are just randomly happen to just move in the reversed direction, all the air goes back where it was, all energy, by pure chance, transfers back in the ball and it comes to lie back on the table. That totally can happen and in that case you would observe the ball... uhhh... falling (?) back onto the table. In that case the entropy in the room (universe) would indeed have decreased on its own, you now had a - from an energetic point of view - more ordered state. Time would have moved \"forward\" but the entropy would have decreased. Yes, that is possible. It is just that the chance for that is 1 to a billion billion billion so we simply do not observe that in the macroscopic world. And that means \"it does not happen\" but if you are mathmatically correct, as a physics book should be, you say \"it is highly improbable\". --- The question posed is answered as good as I can, but lets finally get for a very short glance into Einstein's relativity: based on what is written above Einsteins quote \"Time is what clocks measure\" should be very clear by now. A clock just repeats something in physical world and we count how often that happens. If something in the physical world now - please excuse this expression, but it hits home - screws with how we observe this \"stuff happening in the physical world\" it also and automatically shifts what we consider, percieve and measure as *time*.", "First of all, you have to understand that there is no scientific consensus on this idea. So don't take it as \"this is the way things are.\" Imagine you have a glass of milk on the edge of a table, and you tip it over. It spills on the floor. This happens every time. What about the opposite? A puddle of milk on the floor jumps up into the glass, which then \"un-tips\" itself. This doesn't happen very often at all. In fact, no one has ever seen it happen. If you saw a video of it, you'd say, \"That video is time-reversed!\" That's what Muller means by \"time moves forward\" -- he means that some things, like spilling milk, only seem to happen in one direction, and not the other. The thing is, even though the \"reverse spill\" never happens, it doesn't actually violate the laws of physics. How is that possible? Well, the floor actually contains quite a lot of energy in the form of heat -- all the molecules in the floor are vibrating back and forth randomly. If, by random chance, they happen to vibrate in the right way, they contain more than enough energy to \"pop\" the milk into the air. If they're really lucky, the milk will even land in the glass. Similarly, the molecules of the table are vibrating, and they have enough energy that if they happen to vibrate in just the right way, they can bump the glass lying on its side and tip it upright. I think we can all agree that the \"reverse spill\" is an extremely unlikely event. It requires quintillions of molecules to be moving in *just the right way*. Here's the really counterintuitive thing, though: in a sense, the reverse spill is no more unlikely than the regular spill! This is because, for every possible spill of milk, there is exactly one possible reverse spill. In other words, imagine that an all-powerful being decided to create every possible universe that obeys the laws of physics. For each universe, there would be another universe that is exactly the same except in reverse; this violates none of the laws of physics, so it must be among all the possible universes. And that means for each universe where milk spills, there is another one where it unspills. So, if both the spill and un-spill are allowed under the laws of physics, and they are in some sense equally likely for random arrangements of particles, why do we see spills all the time, and never see reverse spills? This is the question Muller is trying to resolve. One possibility is that the universe is not a random arrangement of particles. Maybe God created the universe so it would have spills and not reverse spills. But Muller is making an argument for a different explanation that doesn't rely on God carefully designing the universe. His argument is this: In all the possible universes, both spills and un-spills are extremely rare -- most of the possible universes don't even have milk, let alone glasses or tables -- and equally so. But they are rare for different reasons. Un-spills are rare because all the molecular vibrations have to happen just right, and so on. But regular spills are rare primarily because *most universes don't have full glasses of milk to spill in the first place*. Once you have found that rare full glass of milk among all the possible universes, a spill is no longer unlikely. So his argument is basically this: Milk spills rather than unspills because we happen to live in one of those improbable universes where there are full glasses of milk. And, in general, if you can think of a process that only goes one way, from start to finish, it's because we happen to live in one of those very improbable universes where the starting conditions exist.", "He's trying to give purpose to an observed function we don't understand. There are far more scientists who would disagree or argue over the concept. We don't currently understand the universe, and as far as we know there is no purpose of its features. Primarily, we just note if the function did not exist, the universe wouldn't exist in its current state, since time is required for reactions to occur. However, that's as astute an observation as radiation is often a bi-product of a nuclear reaction. The only difference is we don't try to give a \"purpose\" to why radiation is expelled, we just describe the occurrence. Perhaps due to the familiarity of time we try and understand \"why\" it's there, but that isn't how the universe or science works. It just \"is\". Additionally, describing time as moving \"forward\" is probably an incorrect way to quantify it, since that implies a relationship from its current state to its previous, even though they do not interact with each other. e: It's also arbitrary to note how our current state of entropy is \"improbable\". We have nothing to compare it to. We can't philosophize the universe at such a scale, we simply don't understand it enough.", "Weird thing about physics. All physics works exactly the same run backwards in time than forwards. Infact if I could magically record the exact motion of every molecule around you for some time, and then do something to the motion of the molecules so the did the same thing in reverse, you wouldn't be able to tell the difference between that happening in reverse but forward in time, or if you were moving backwards in time. When you put some milk in your coffee there's no physical reason it shouldn't unmix, or for that matter that it shouldn't blink in and out of existence. There's no physical reason we can describe that the past is any different from the future. It obviously *is* different. If you spill that coffee on the ground it won't spontaneously unspill halfway to the floor even though there's no reason why it couldn't. Entropy however provides an argument for why this must be the case, even if it doesn't explain why. In short, entropy is basically the one thing that isn't reversible. If you have something in an ordered state, it will only become less ordered. Entropy always increases is why your the milk in your coffee won't unmix. The universe doesn't really make physical sense without that rule, but it's a propery of statistics, not physics. However if time went in reverse you could watch your coffee unmixed the milk go back back in the carton, the oils go back into the bean, the beans ungrind, etc. And because physics doesn't care which direction something is moving through time, this would be exactly equivalent to entropy decreasing.... which can't happen. There's one small issue with this argument. It's enough to argue that time must flow in *a* direction, but not which. The past and the future should look similar and thus there should be no inherent preference to which time moves towards. We need make one more claim for a preference towards the future: In the past the universe was in a state of extremely low entropy. If so the past and the future would look very different. Turns out, as best as we can tell that's the case. The universe were highly dense in the past, [big bang cosmology]( URL_0 ) etc implies really really really low entropy."], "text_urls": [[], [], [], ["https://en.wikipedia.org/wiki/Big_Bang"]], "score": [102, 9, 4, 3]}}, {"q_id": "6t9rsd", "category": "Repost", "title": "Why is it that the Moon's gravity effects our tides, yet if a satellite were to fly in between the Earth and Moon it wouldn't get effected?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dliz07u"], "text": ["Satellites are actually impacted by the gravity of the moon, but drifting a few meters in orbit isn't that big a deal."], "text_urls": [[]], "score": [20]}}, {"q_id": "6tafdn", "category": "Repost", "title": "what happens if I fire a gun in space?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlj4b3c", "dlj4h7z"], "text": ["The bullet will leave the barrel at high speed, but a slower speed than it would on Earth. You will begin traveling backwards since you absorb momentum to cancel the momentum of the bullet The bullet will continue to move at the speed it left the barrel for a long time. It will slow slightly due to particles it encounters in space but there are so few it will be a long time before it slows due to friction. Depending on what direction you shot it, it may speed up or slow down due to the effect of gravity, the bullet is now in a ballistic trajectory. If you shot it in the right direction at the right speed it will achieve orbit of the most dominant object in the area, otherwise it will either leave that objects sphere of influence or be captured by it and fall to the surface", "Yer not alone in askin', and kind strangers have explained: 1. [ELI5: Gun fired in space. ]( URL_0 ) 1. [What happens when you fire a gun in space? ]( URL_5 ) 1. [What happens if you fire a gun in space? ]( URL_6 ) 1. [ELI5: what happens if you shoot a gun in outer space? Can a country \"claim\" a portion of space as a territory? ]( URL_2 ) 1. [ELI5: what would happen if you fired a gun in space? ]( URL_4 ) 1. [ELI5: What happens when a gun is shot in zero-gravity? ]( URL_1 ) 1. [ELI5: What would happen if you shot a gun in space? ]( URL_3 )"], "text_urls": [[], ["https://www.reddit.com/r/explainlikeimfive/comments/1kafgd/eli5_gun_fired_in_space/", "https://www.reddit.com/r/explainlikeimfive/comments/4ct0aq/eli5_what_happens_when_a_gun_is_shot_in/", "https://www.reddit.com/r/explainlikeimfive/comments/2hxdls/eli5_what_happens_if_you_shoot_a_gun_in_outer/", "https://www.reddit.com/r/explainlikeimfive/comments/1quw94/eli5_what_would_happen_if_you_shot_a_gun_in_space/", "https://www.reddit.com/r/explainlikeimfive/comments/2bh3hx/eli5_what_would_happen_if_you_fired_a_gun_in_space/", "https://www.reddit.com/r/NoStupidQuestions/comments/2ksccj/what_happens_when_you_fire_a_gun_in_space/", "https://www.reddit.com/r/NoStupidQuestions/comments/4c924t/what_happens_if_you_fire_a_gun_in_space/"]], "score": [10, 6]}}, {"q_id": "6te7jk", "category": "Repost", "title": "Why is hot water a bit white when it comes out of a tap ?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlk0ksq", "dlk0kdf"], "text": ["Dissolved air bubbles. When pour a glass of hit water, it often has air trapped in it. If you pour more slowly, or let it settle, you'll see the water looks clearer. Small air bubbles appear white because they contain many reflections of the environment.", "Tap water often looks whitish due to tiny bubbles of air. Let sit for a few minutes and it'll probably be gone. (air dissolves more readily in cold water, this is probably why you don't see it)"], "text_urls": [[], []], "score": [11, 5]}}, {"q_id": "6tfj49", "category": "Repost", "title": "How is Hiroshima inhabitable, but Chernobyl is uninhabitable?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlk9bx4", "dlkaav9"], "text": ["Hiroshima had around 140 pounds of nuclear material in it, Chernobyl had over 800 tons of nuclear material.", "I looked up the difference between a nuclear reactor accident and a nuclear weapon, and [this article]( URL_0 ) has the best explanation. I've spent a good deal of time reading the timelines of Chernobyl and Fukushima, so some of this comes from that past reading. I'm not a subject matter expert, just curious. Basically, when a nuclear weapon is detonated as an air burst, or at high altitude above the target, then the dust from the ground and destroyed buildings doesn't mix as much with the radioactive material and thus doesn't become radioactive itself. Air burst is the common goal of attacking targets with nuclear because it maximizes the exposure of the explosive force to the ground. Also, a bomb is an uncontrolled reaction which uses up the radioactive fuel instantly. In a reactor, the controlled reaction has fuel which is meant to be used over time. The fuel has an intentionally long life of radioactivity. Furthermore, there are other elements of the control system which become contaminated by radioactivity, namely the control rods, the cooling water, and the components of the system that contain the reactor. All of this stuff remains radioactive for years after being exposed to nuclear fuel. This is planned, and honestly the industry still doesn't have a long term disposal plan for all of this waste. Then, in a meltdown situation, the control system has failed, and the nuclear fuel reaches high enough temperatures that it melts together, preventing any more control of the reaction. Temperatures continue to rise as the reaction proceeds uncontrolled. The fuel \"melts down,\" literally, seeping through the case of the reactor as it melts through. In Fukushima, they think that the pile of molten fuel has re-solidified on the concrete floor of the building. The radiation continues to be so high that robots sent in to film and transmit video fail after exposure to this radiation. So then the only thing to do is to wait for the fuel to cool and to spend itself out in the reaction process, and hope to God that it doesn't melt through the concrete itself and get into the ground. Theoretically(most likely not in Fukushima anymore), the fuel pile could melt through the concrete, the ground, and then begin vaporizing the groundwater, shooting radioactive steam out in whatever direction has the least resistance. One last effect which happened in Fukushima. The reaction releases hydrogen gas, and that gas built up in the building. It exploded and blew apart the building itself, which then exposes circulating environmental air to the reaction. This would increase the range at which the area would need to be cordoned off to ensure people are not exposed to radioactive air. In case this terrifies, know that modern reactor designs are much better and safer. Chernobyl was an unforced error by foolish, politically appointed managers of the reactor who bypasses safety protocols to impress their superiors. Fukushima is a tragedy of exceeded design parameters as far as flood control and effective backup power for cooling systems. The key is to learn lessons from these tragedies and make preparations at existing legacy reactors to ensure meltdowns don't occur. And of course build only the better kinds of reactors in the future."], "text_urls": [[], ["https://www.quora.com/Why-is-an-exploding-nuclear-power-station-more-dangerous-than-a-nuclear-bomb"]], "score": [5, 3]}}, {"q_id": "6th303", "category": "Repost", "title": "How come animals the size of Dinossaurs never inhabited Earth after Dinosaurs were extinguished?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlklkjo"], "text": ["Because previously the earth's atmosphere had a much higher concentration of oxygen in the air meaning that the respiratory system was able to absorb enough oxygen for aerobic respiration in all the cells of the larger animals (that's why you hear about the massive insects that lived then, the high O2 concentration allowed them to respire more and so inevitably grow to larger sizes."], "text_urls": [[]], "score": [8]}}, {"q_id": "6thefb", "category": "Repost", "title": "Why isn't all money in coin-form? Don't coins last longer and aren't they much harder to counterfeit?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlknkni", "dlknv8l"], "text": ["Yes... but aren't they also a lot heavier, bulkier, and harder to transport? Also, part of their difficulty in counterfeiting is from the expense of doing so. You may say to my above question that we could make it less bulky by making $5, $10, $20, and $100 coins. But for $100 a piece, a criminal might be more inclined to find a machine that can press coinage and make fakes. For $1 max, it's not worth it.", "Coins are not as convenient to carry around as bank notes. Right now I have about 20 notes of various denominations in my wallet, but whenever I get even a few coins I don't know what to do with them. I try to get rid of them as fast as I can! The durability is not an issue since new notes are created and old ones retired routinely. And a good thing too, as they don't last very long ( URL_1 ) Note that it costs the mint about 8 cents to make a quarter, while the fed say's it is about 12 cents for a 20 dollar bill, so cost probably not the driver. (Source: US Mint 2016 annual report, and this [page from the fed.]( URL_0 ) )"], "text_urls": [[], ["https://www.federalreserve.gov/faqs/currency_12771.htm", "https://www.federalreserve.gov/faqs/how-long-is-the-life-span-of-us-paper-money.htm"]], "score": [3, 3]}}, {"q_id": "6tirec", "category": "Repost", "title": "why does scraping scissors against a strip of ribbon create a curled strip of ribbon?", "title_urls": {"url": []}, "selftext": "This also happens with hair when pinched and pulled.", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dll670b", "dll0fxv"], "text": ["There's a really handy sci show video about this topic. It's due to a force called Yield where a certain amount of force will deform something permanently. But only the outside of the ribbon is deformed and stretched making it curl away from that side URL_0", "The friction on the band between, say your finger, and the sharp scissor blade moving against the ribbon (being held in place or pulled opposite) with enough force (stretching) causes the fibers in the ribbon to deform and shorten because of exceeding the molecular elasticity and therefore pulls on the strip from both sides where its elasticity has changed enough that the structure of the fibre itself is actually altered Simpler answer: When you apply enough force to a ribbon to exceed the force that keeps the fibers intact, the fibers deform around the area you applied the force to, but not around others, so now some parts of the ribbon are actually different length than others, making it curve. EDIT: Made it more ELI5 as I agree with /u/Vardelet"], "text_urls": [["https://youtu.be/zsyEMSxN9TM"], []], "score": [26, 24]}}, {"q_id": "6tmyb3", "category": "Repost", "title": "why do we sometimes stick out our tongues slightly when we're concentrating hard on something?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlm15iw", "dlm44uh", "dlm1i3b", "dlm5t3c", "dlm6mbb", "dlm5rqw", "dlm58tj", "dlm8y70", "dlmb7n6", "dlm6py9", "dlm189w"], "text": ["Certain portions of the human brain are double-tasked. Ever wonder why you look up or down while doing difficult math? Eye movements and problem solving are both happening in the same part of the brain. ( URL_0 ) It's likely the same thing with sticking your tongue out. the part of your brain that's concentrating also has some other job that just kind of happens randomly while your brain is putting all resources into one task.", "Tongue position also can have a big impact on strength. Here's an [ELI5 explanation]( URL_0 ) (with scholarly article link). Essentially, the tongue and brain are wired pretty tightly together, from a nerve standpoint. It's pretty cool!", "I've read somewhere before (and currently on much break can't look for source) that the nerves that run through our hands and the nerves that run through our mouth connect to the brain in the same spot. So when you are completing a fine motor task with your hands you will often stick your tongue out or bury it in your cheek as a kind of side effect.", "I'm surprised there's no comments about the level of concentration and competitiveness that Michael Jordan played with and how he's known for always having his tongue out before or as he's doing some ridiculously acrobatic stuff.", "Also why do we strain our face when exerting force with our arms or legs? Sometimes I realize I'm doing this while working out or whatever and will consciously try to keep a straight face.", "I understand that sticking out the tongue is a refusal sign that babies use when they don't want to feed. Something similar is used sometimes by adults when they want to refuse something, make an expression of disgust, or, as in this case, to block things out so they can concentrate. Desmond Morris has some pretty interesting books on body language, which is where I learned this.", "It's a natural display to others that you are thinking and do not want to be communicative. No one talks with their tongue out and mouth closed, so it means \"im concentrating, don't expect me to speak\".", "This is called an overflow movement, and is seen more often in children with ADHD and, I believe, autism.", "Ever hear of guitar face? A lot of people make a face when doing a solo on a guitar, probably happens when the brain is stimulated on both things: guitaring and face movement. P.S. this face is not only limited to guitars, it can happen with other instruments too. :p", "The creepy old lady cashier at the Circle K in the neighborhood I grew up in would always have her mouth open with her tongue out swishing around aimlessly while ringing you up. Damn it was creepy.", "Your tongue uses a lot of brain power to move around and do things in your mouth. By sticking it out and holding it still, takes less brain power and keeps brain from being distracted while you focus."], "text_urls": [["http://cognaction.org/rdmaterials/php.cv/pdfs/incollection/spivey_dale_2011.pdf"], ["http://zhealtheducation.com/episode-191-get-stronger-immediately/"], [], [], [], [], [], [], [], [], []], "score": [885, 120, 55, 19, 18, 10, 7, 5, 4, 3, 3]}}, {"q_id": "6tnwar", "category": "Repost", "title": "Why are gas prices allowed to fluctuate multiple times a day, when other shelved products remain at a constant price for a year or more (with the exception of occasional sales)", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlm40hv"], "text": ["> I don't understand how this is able to happen? The fuel being sold has already been purchased at a set cost. Regardless of current events, that fuel was already processed, purchased, and delivered, so why isn't it being sold to recuperate that original purchase? OK. There are 2 issues in there that you are having. First of all the government does not control what stores sell the product for. Stores can adjust their prices however often they want to whatever amount they want. Customers then make the choice if they wish to purchase or not. So to answer \"how can this happen!\" the answer is that these are private companies that can do whatever they damn well please when it comes to selling their products. The other thing you mention is that the selling price of an item should be somehow tied to the cost to purchase that item. If I buy a $100 thing I should sell it for $110 or $150 and not $1,100 because that would be unreasonable. I understand this thinking, but it's flawed. The selling price of an item is tied only to the demand for that item and the supply of that item. How many people want it and how much of it is there available. In an ideal world, a store would increase or decrease the selling price until the number of people who want to buy (at a price) exactly equal the amount of an item that's available. This maximizes the retailer's profit. Let me put it to you another way. Let's say I sell a thing. I'm the only one who sells this thing and while my overall market is limited and small I'm the exclusive supplier so I do ok. I sell 100 things per month for $100 and each one costs me $50. So I bring in (100x100) $10,000 in revenue and have $5,000 in costs. I make a decent living selling these things. One day I decide to undertake a project. I discover a way to make these things for cheaper. It took me years and years to discover this process but now I can make them for only $10 rather than $50. Now, who should benefit from this discovery, me or my customers? Remember it's a very niche product, it's not like I'll sell more if I lower the price. only 100 people per month want this thing and that's all I'm ever going to sell, 100 per month. I believe that I should benefit from all the work I put into developing this new process. So I keep my price the same, sell the exact same number of things per month ($10,000) worth, but now I only have $1,000 in costs so I make much more money. This is all to point out, the cost of an item and the selling price of that item are not related values. As long as the sale is profitable the retailer will price an item where they believe they will maximize their profit, not give customers a discount because the cost to manufacture went down. As this relates to gas, the retailer is selling you gas based on the price it will pay to replace the gas that you just bought. As demand for gas goes up, the price of gas goes up because people want more of it but there's still a fixed amount."], "text_urls": [[]], "score": [6]}}, {"q_id": "6to6f0", "category": "Repost", "title": "How can a cell phone receive a 4G, 3G, 2G, 1G, and no signal in a short time (10-15 minutes) without physically moving location or orientation?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlm8225"], "text": ["A huge Pokemon-Go raid appears near your location But seriously, there are a lot of factors that can play into signal reception. It could be the weather, a network issue, something about objects/obstacles between you and whatever tower your phone is trying to connect to, the number of other users nearby and their data usage, internal phone operations and power consumption, and network-specific issues occurring within the tower network backbone."], "text_urls": [[]], "score": [12]}}, {"q_id": "6tpcie", "category": "Repost", "title": "We carry 4k cameras around in our pockets. Why are television/movie studio cameras still massive?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlmfuil", "dlmfw1z", "dlmgo91"], "text": ["> We carry 4k cameras around in our pockets. Why are television/movie studio cameras still massive? The 4k capable cameras in our pockets are terrible compared to the big studio cameras. The professional cameras have much better and larger sensors which have a larger dynamic range, less noise, and better color response. Other major factors are the ability to mount better lenses, electronics to support various things like higher frame rates, methods of storing footage and pulling it off the camera quickly, power for accessories like screens, remote viewing of shots and composition, connecting microphones such as boom mics, wireless lapel mics, image stabilization solutions such as powered gyroscopic Steadicam, mounting points for cranes, the list goes on. It is cool that we have very capable cameras in our pockets but your phone simply can't handle everything a movie set demands.", "Apart from the basic quality issues people already touched on, zoom. In order to get a close shot on someone's face you'd need to be literally like 6 inches away with a cameraphone. All zoom there is digital zoom which reduces the overall visual quality. Imagine shooting scenes with cameras all 6 inches from people's faces.", "Resolution, especially on a phone, is more of a marketing gimmick than anything else. There are many more important things that go to recording high quality video. A camera lens works on a physical level. A bigger lens = more light can get in and it produces a better image with lots of qualities we associate with professional cinema like steep dropoff of depth of field. While phones find some ways to imitate these things like using software to blur backgrounds and dual cameras to generate an artificial depth of field, nothing beats the real thing, especially since the real thing gets more advanced every year just like phones. On top of that are the many manual controls. These things take up space because crew need to be able to shift stuff precisely and quickly. A knob you can turn with your hand is much more precise and quick than a touchscreen. Phones have basically no controls - pretty much everything is done automatically. This obviously will not work in cinema when people are using the tools of photography in order to force a viewers perspective and create an artistic whole. A director sees what he wants in his head and the DP makes it happen - software cannot be relied on, especially when that software is meant for teens taking selfies, not for filmmaking."], "text_urls": [[], [], []], "score": [27, 6, 3]}}, {"q_id": "6tq5hb", "category": "Repost", "title": "What is nuclear radiation, and how does it actually kill people?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlmn3k9"], "text": ["The kind of radiation people worry about from nuclear technology and the like is called _ionizing_ radiation. That means that it has the ability to mess with molecules by stripping off electrons and changing their chemistry. Biological systems are very intricate, complicated \"machines\" that require chemistry to work correctly. Imagine taking a .22 rifle and shooting it through a circuit board of a computer. Will the computer still work afterwards? Maybe \u2014 but probably not. The radiation here acts like the .22 bullet. In most cases if it messes with a cell, it'll just break the cell and that will kill it. Cells die all the time, and have means of \"self-destructing,\" so losing a few cells is no big deal by itself. Lose too many at once \u2014 like billions and billions \u2014 and you start to suffer health consequences. Only _really_ radioactive sources can do this to you, but absorb enough radiation in the short term and whole systems of your body will shut down, injuring or even killing you in the short term (e.g., a week or so at most). There is also a small but real chance that any one of those radioactive particles will modify the cell's DNA (in the same way as before \u2014 by messing with its chemistry), and a small but real chance that the modification in question will make the cell turn cancerous. So even if the radiation you absorb doesn't hurt or kill you, it can raise your chances of cancer \u2014 there is a probability of one of your cells having become cancerous. Your base lifetime fatal cancer risk in the USA is about 20%. A dose of 1 Sievert \u2014 a pretty heavy amount (5 Sieverts is usually fatal) \u2014 increases your fatal cancer risk by about 1% (which is to say, in a population of people exposed to 1 Sv, you'd expect to see 1% more cancers than if they hadn't been exposed). Radiation can pose a contamination problem from two angles. The first is that some radiation poses a chance of making other things radioactive. So neutron radiation, for example, can \"induce\" radioactivity in non-radioactive substances. Aluminum, for example, can get very radioactive if exposed to neutron radiation. I don't think your hypothetical chicken is likely to be a radiation threat just because it was irradiated, though, but this is an issue with massive sources of neutrons (like nuclear reactors, nuclear weapons, or particle accelerators). The other angle is through contamination by radioactive products. In this case it is not the radiation itself that is the contaminant, but the fact that there is \"radioactive dust\" that is a contaminant. So when a nuclear weapon explodes, it creates lots of tiny radioactive particles called fission products that then go up into the mushroom cloud. These can attach to dust or water molecules and then fall back to Earth. These fission products are versions of \"normal\" atoms, like iodine, that are somewhat broken. So regular iodine (Iodine-127) is good for you and so your body takes iodine that it finds (e.g., that you eat) and moves it into places in your body where it can do some good (like your thyroid gland). Great. But nuclear reactors and nuclear explosions create radioactive iodine (Iodine-131), which is chemically identical to the \"good\" iodine but will emit radiation. Your body can't tell which is which (because it uses chemistry to tell the difference), and so it takes the \"bad\" iodine (Iodine-131) and puts it in your thyroid gland as well. Once its there, it will decay away, releasing radiation, and exposing your thyroid gland to it, increasing your chance of thyroid cancer. So in your chicken example, if your chicken is contaminated by radioactive byproducts \u2014 e.g., that it ate or drank or breathed \u2014 and then you eat the chicken, now you've got those same byproducts in your body. Depending on the byproduct, it might just be excreted after some amount of time (your body can't do much with, say, uranium) but others might be either something your body like (like iodine) or chemically similar to things it likes (strontium is similar to calcium, and your body likes calcium) that your body will take these \"broken,\" unstable atoms and move them into places where they shouldn't be (like your thyroid gland, your bones, etc.). Animals are affected by radiation as well (as are plants!), though the damage can vary by species (insects, including but not limited to cockroaches, are famously more immune to radioactivity than mammals). For long-term cancer risks, some animals lack the lifespan to really suffer from cancer visibly (the cancers can take decades to develop, and if your species' lifespan is only 5-10 years, you probably won't see radiation-induced cancers), so it doesn't always pose the same threat to them as it does to humans (who live relatively long lives compared to most animals). At high-enough dosages of radiation, practically any living thing will suffer \u2014 with high-enough radiation you can even kill trees (it's been done experimentally)."], "text_urls": [[]], "score": [3]}}, {"q_id": "6tr0kt", "category": "Repost", "title": "How come people have been around for hundreds of thousands of years, and then suddenly in the past 100 years we've gone from horse and buggy to spaceships and up close pictures of Pluto?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlmtnxh", "dlmtnv3", "dlmtrc7"], "text": ["Sanitation, vaccines, better nutrition, and safer city states to name a very few of an incomplete list of things that allowed us to look beyond the formidable tasks of daily survival. For most of our sorry history, we lived short miserable lives.", "Those discoveries and developments are just products of the previous eras. Human population has been growing exponentially, and you need a certain amount of population to allow some people to be idle inventors, rather than farmers or other providers. At the end of the 18th century, more and more people were able to develop machines because they had time, sparking the industrial revolution. This snowballed, releasing more people from farming and allowing more inventions to be designed and implemented.", "I think the boom can be attributed to the industrial revolution. The industrial revolution was not so much of an advance is technology as it was a different way of thinking. For hundreds of thousands of years before, the only way people could ever imagine something being made was by hand. Quality over quantity. That whole concept was turned upside down with the industrial revolution. Instead of things being made by hand, they were made by machine. Quantity over quality. That shift in thinking lead to our current situation."], "text_urls": [[], [], []], "score": [3, 3, 3]}}, {"q_id": "6tsd0z", "category": "Repost", "title": "Why does blood, semen and other bodily fluids glow under a black light?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dln644g", "dln5jzb"], "text": ["Ahoy, matey! Yer not alone in askin', and kind strangers have explained: 1. [ELI5:Why are body fluids detectable with UV light? ]( URL_0 ) 1. [Eli5: how is it possible to see traces of blood or semen under special lighting even when the area looks completely clean. ]( URL_2 ) 1. [ELI5: Why is blood visible under UV light? ]( URL_4 ) 1. [ELI5: Why does sperm show up under a blacklight? ]( URL_1 ) 1. [ELI5: Why does semen show under blacklight? ]( URL_3 )", "I don't think it really does that much. I had one to check for dog stains and it didn't really work. At least on tv they spray with a chemical and then the bodily fluid glows under black light."], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/3c64te/eli5why_are_body_fluids_detectable_with_uv_light/", "https://www.reddit.com/r/explainlikeimfive/comments/6lxmf5/eli5_why_does_sperm_show_up_under_a_blacklight/", "https://www.reddit.com/r/explainlikeimfive/comments/4el3eh/eli5_how_is_it_possible_to_see_traces_of_blood_or/", "https://www.reddit.com/r/explainlikeimfive/comments/35ngso/eli5_why_does_semen_show_under_blacklight/", "https://www.reddit.com/r/explainlikeimfive/comments/1orlip/eli5_why_is_blood_visible_under_uv_light/"], []], "score": [6, 3]}}, {"q_id": "6ttsbw", "category": "Repost", "title": "Why laptops still use differrent chargers, and why they dont follow the example of the mobile phones?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlnes9p"], "text": ["$$$$$$$$$$$ Same reason apple uses its own cords. You have to buy them from the company that makes the laptop."], "text_urls": [[]], "score": [8]}}, {"q_id": "6ttvtc", "category": "Repost", "title": "Basics of Electricity, Volts, Amps etc..", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlngyll", "dlnfyfy", "dlnpplg"], "text": ["When this question comes up, I like to show [this]( URL_0 ) cartoon. An easy way to think about electricty, is to think about it like the flow of water. Volts is water pressure, amps is gallons per minute, and ohms measures the resistance water must overcome to flow. Watts is a measurement of enegery, and it can be calculated by multiplying amps times volts. Going back to our water analogy, think of a pressure washer. If your pressure washer's pressure stayed the same, but put out more gallons per minute, it's easy to understand how your flow of water has more ability to do work. The same is true if your GPM was constant, but the pressure increased. Single phase vs 3 phase is slightly more in-depth. In the US homes are generally run off 120 volt AC power. AC stands for alternating current. Imagine your pressure washer started off with out any pressure, increased to 120 psi, fell back to 0 pressure, then sucked up water at 120 psi. It does this many many times a second. (Like a wave) While you are pressure washing your driveway, you think about how much more power your pressure washer would have if it didn't take time to go from full flow, to suction. Well what if you had 3 pressure washers, all a little out of sync from one another? While pressure washer A is at 120 psi, pressure washer B would be at 40 psi, and pressure C would be at -40 sucking up all that dirty water. [The power of the 3 pressure washers working together would be more than any single could produce by itself.]( . Hope that helps", "Think of water flowing through a pipe. Volts is the water pressure Ohms is the resistance from the pipe (diameter, ect) Amps is the gallons per minute passed through the pipe.", "All the water analogies are kinda useful as conceptual aids but they don't really explain much about elecricity at all. First thing that is important to understand is that electricity and magnetism are very closely related concepts. They are so related in fact that it is formally impossible to distinguish between them. Electric fields and magnetic fields are both manifestations of the same phenomenon. The difference between electricty and magnetism is one of reference frame. (we say that magnetic fields are lorentz transformed electric fields and vice versa) and we call the entire phenomenon electromagnetism. It is in fact impossible to separate them. looking at one withouth considering the other is only possible through simplification and careful constraints of our descriptive model. The theory of electromagnetism is quite old. Older than einstein's relativity theory but it's formalism was so well established that Maxwell's theory of electromagnetism survived Einstein's relativity and we still use it to this day. Behind all the nice formulas and ideas you learn in school are a series of differential equations and their solutions. Maxwell's equations are differential equations. Diferential equations are complicated beasts and it takes advanced mathematics to work with them. A differential equations looks just like a normal equations except some/all of it's terms consist of derivatives. Derivatives indicate the rate of change of variables in relation to other ones. Differential equations are therefore equations of change. They describe how certain quantities change in relation to each other (differential as in difference) This is all fair and nice but now imagine we want to describe electricty without being forced to spend several years learning advanced calculus. No problem. we can create a simpler model that approximates the real world close enough for our porpouses. As long as we are careful to stay within certain constraints, our model should be preety accurate. However, we might need to adapt or expand it if we want to deal with specific situations outside our model's scope. The simplest model we use when dealing with electricty 101 is called the electrostatic aproximation. We can do a lot with this model. We can use it to predict many real world behaviours of electricity and we can understand 90 percent of all common electric circuits with it, but only as long as we keep within our model constraints. For the electrostatic aproximation our constraints are no time-varying (changing with time) electric or magnetic fields. if there are electric currents or magnetic fields they should be either constant or only change very, very slowly Now that our model and constraints are established lets look at the most common concepts of the electrostatic world: The basic building block of Electricity is the electric field. Fields are basically regions of space that have certain properties. The electric field describes the magnitude and direction of the force an electrically charged particle experiences on itself when placed in a certain region of space. You can have both negative and positive electric charges. similar charges repel and opposite charges attract each other. This repelling/attracting force is called the coloumb force. The unit of electric charge is the coloumb. More charge results in more force between charged objects. larger distances results in less force between charged objects. In a sense this is all there is to know about elecricity. electrically charged objects will experience forces in an electric field. The direction and magnitude of the force is related to the charge of the object and the specific electric field it finds itself in. Now lets set up a simple thought experiment: We set up on either end of a room two separate boxes. We fill one with a lot of negatively charged spheres and the other one with the same number of positively charged spheres. What will happen ? well we know from coloumbs formula that the spheres inside of each box will repel each other. so inside each box the spheres will try to separate as much as possible. Most of them will end up evenly spread scross the box's inner sufrace. This is now how we can imagine electric charges to be distributed across an electrically conductive charged body. Next we bring the boxes next to each other. We know the spheres in each box now attract the ones in the other box. We will find inside the first box that most spheres have accumulated in the side of the inner wall facing the other box due to being atracted by the spheres inside the other box. The inner wall where the spheres accumulated is now more charged than the opposite wall. This separation of charge in the precense of other charged bodies is called induction. Now an important question. If the spheres are atracted.Why aren't the spheres jumping from box to box to meet each other ? well because the box has walls. Remember, The electric attraction is still there as we saw from our induction experiment. it is the wall itself that is stopping the spheres from meeting each other. If we wanted the speheres to meet each other we would have to increase the magnitude of this attractive force until it was strong enough to break the wall. We could call the wall a resistor. Since it resists the movement of charges in the precense of electric fields that arent strong enough to overcome it's resistance. Electric resistors work preety much like that. The unit of resistance is the ohm and it defines how much spheres will manage to break a hole in the wall per second given a certain magnitude of the electric field. To overcome this resistance we could make the atracting force stronger. for example by making each sphere have 10 times as much charge. Eventually the walls wont be able to hold and spheres will start flowing between boxes. This is the same as increasing the voltage in a real circuit. The unit of voltage is the volt and it defines the strenght of a electric fields on electric charges. A much easier way tho is just to build a tube connecting both boxes. We can call this tube the conductor, because it will conduct our charged spheres to where they want to go. A larger tube will carry more sphere's per second and so will have a lower resistance. Adding obstacles inside the tube will instead reduce the amount of spheres that make it through and will thus cause the recistance of our tube to increase. Not all tubes are the same and therefore not all conductors are the same. Some are better and some are worse, the unit of conductance is the siemens. Now that we have a nice conducting tube connecting both our charged boxes. spheres will start to freely flow between them. Positive spheres will flow one way and negative spheres will flow the other. However, since we are smart, our unit of current changes sign depending on the respective charges. So positive spheres moving one way count the same as negative spheres moving the other way. The spheres per second that flow through our tube ( when considering their charge) is our current. The unit of current is the ampere. So, now we have defined our most important electrostatic units. Electric charges are measured in coloumbs. Obstacles for our charges are called resistors and are measured in ohms. Paths for our charges are called conductors and are measured in siemens (1/ohm). The strenght of the electric field in a given area of space is measured in volts. Moving charges are called currents. How many charges pass through an area of space in a second is our current and it is measured in amperes. Now we have given ourself a nice simple and consistent model to deal with electrostatic situations. Yet, we havent considered what we can do with this knowlede. For this we will have to expand our model with ideas of energy and power. which are not really exclusive to electricity and therefore outside the scope of this explanation. For this we will have to introduce the idea of watts/volt-amperes into our model. Then we will find that we cant really separate electricty from magnetism as cleanly as we hoped. Specially as soon as we start looking at dynamic systems ( all real life systems are dynamic). we will need to introduce the magnetic field and ideas like magnetic voltages. Lastly we will find out that charges and conductors are not really needed for an electric field to exist and that Electro/magnetic fields are not things you can separate into one or the other. We will free ourselves from the constraints of our conductors and consider electro-magnetic fields travelling freely through empty space. To finally arrive at the concept of electromagnetic waves. At this point we would have covered about two/three semesters of higher studies in electromagnetics but we would still have a lot to learn There is sadly still a lot more to explain but this post is already too long. If you have any specific questions feel free to ask tho."], "text_urls": [["http://tkovapor.com/media/wysiwyg/Ohm_s_Law.jpg"], [], []], "score": [19, 5, 3]}}, {"q_id": "6tu63r", "category": "Repost", "title": "How did humans come to value Gold so highly? Just because it's pretty?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlnida4", "dlnmdwf", "dlnq0p5", "dlnqjex", "dlnhs66"], "text": ["Gold has a number of characteristics that make it useful as money: * Gold is fungible. So any ounce of gold is very replaceable with any other ounce of gold. Take diamonds for example as another rare shiny mineral with unique properties, some have inclusions, some have less color, some are naturally larger crystals, etc and all those impact the rarity of the diamonds (large, colorless, diamonds with no inclusions are really rare, small brown diamonds with lots of inclusions are quite common). * Gold is malleable. That means it can be hammered into shapes without heating it, and can be divided with very basic tools. That's a very useful characteristic under the barter system, as it allows easy trade in something worth only a little. Further, gold isn't often valued as a large nugget, so reshaping it doesn't reduce its value. * Gold is a very stable element. It's tough to oxidize, corrode, dissolve, etc. It takes a specific combination of two acids to dissolve, and it can sit in seawater for centuries without corrosion. That means when an ancient rich man stored gold somewhere, it was likely to remain in good condition until removed. * Gold is very dense. There are only 3 elements more dense than gold (and they're quite rare) and the one element that's similar in density to gold wasn't isolated until pretty recently. That density gives it a strong protection against counterfeiting, and an easy means to check, all you need is a scale, a string some water, and a means to hold the water. * Finally, it's rare enough that it has quite high value (so a man can easily carry enough gold to make even large purchases). Those characteristics all led many early humans to make gold their money, once they'd encountered enough of it.", "In addition to all the other things listed here, gold is also easily measurable. As an element, gold has a fixed weight. You can weigh something gold and determine how much gold there is in it, compared to what other materials there are in it. That makes it easy to standardize. That's what got Archimedes so excited when he discovered displacement; he was asked to determine if a crown was made of gold, or if it was made of something else, and to do it without destroying it. When he observed the effect he had on his bath water, he knew he could measure the displacement and replicate the effect with other objects and compare them to each other. Which would give him the information he needed to measure the crown without destroying it.", "**Gold has a steady amount of expended work required to mine it. ** Many of the other posts point out the malleability, and rapid identifiability of real gold. But the fact that gold represents a fairly stable unit of labor for production is what makes it valuable as a token of a unit of work. It may sound strange but this is what makes money valuable: the amount of effort wasted to produce it could have been used to do some other task. In a given society, even as tools of mining improve, those same labor saving tools and technology can generally be put to use in other endeavors - making spending them mining fixed in value to the opportunity cost of not using them producing food or other goods. This is also what is behind the \"wasted\" computer resources required for \"mining\" bitcoins. It establishes an opportunity cost of producing the currency. **Currency is extremely abstract. **Even more than we tend to appreciate today. One extreme example that points this out are **Rai stones.** On the island of Yapp and nearby, inhabitants used to use giant 1-3 meter tall rings of stone mined from distant islands and precariously hauled by canoe as currency for large transactions like marriages or houses. The actual currency being so heavy, the stones often didn't even have to move to change ownership. People just kept track of who owned what. A house would change ownership and in exchange so would a stone. In fact, there is at least one example of a stone being quarried and cut but lost in the sea when the canoe capsized. Everyone agreed that although they couldn't see it, the stone must still be there at the bottom and that it could still be traded just the same as any other.", "Ahoy, matey! Yer not alone in askin', and kind strangers have explained: 1. [ELI5: Why is gold so valuable? ]( URL_0 ) 1. [ELI5: Why is gold valuable? Also, why was gold important to ancient civilizations? ]( URL_2 ) 1. [ELI5: Why is gold so valuable? And why is it more valuable than other metals, like silver? ]( URL_1 ) 1. [ELI5: Why is gold worth so much money in modern times? ]( URL_4 ) 1. [ELI5:Why is gold used as a store of value? ]( URL_6 ) 1. [ELI5: Why is gold so valuable to the world? ]( URL_7 ) 1. [ELI5:The infatuation that humans seem to have with gold? ]( URL_3 ) 1. [ELI5: Why gold is considered valuable? Why were currencies compared to the amount of gold? ]( URL_5 )", "It has aesthetic value, but it is also malleable and ductile, letting us do a lot with it. It's very resistant to corrosion, so it lasts a very long time. And less useful in the past, more of a modern note, it carries electricity very well. Add all that to the fact it's rare, and you have a nicely valuable substance."], "text_urls": [[], [], [], ["https://www.reddit.com/r/explainlikeimfive/comments/535k5x/eli5_why_is_gold_so_valuable/", "https://www.reddit.com/r/explainlikeimfive/comments/1utlb8/eli5_why_is_gold_so_valuable_and_why_is_it_more/", "https://www.reddit.com/r/explainlikeimfive/comments/6hqho6/eli5_why_is_gold_valuable_also_why_was_gold/", "https://www.reddit.com/r/explainlikeimfive/comments/2ttvbb/eli5the_infatuation_that_humans_seem_to_have_with/", "https://www.reddit.com/r/explainlikeimfive/comments/1mhujj/eli5_why_is_gold_worth_so_much_money_in_modern/", "https://www.reddit.com/r/explainlikeimfive/comments/2fxbdw/eli5_why_gold_is_considered_valuable_why_were/", "https://www.reddit.com/r/explainlikeimfive/comments/1xmgj8/eli5why_is_gold_used_as_a_store_of_value/", "https://www.reddit.com/r/explainlikeimfive/comments/2s2k4d/eli5_why_is_gold_so_valuable_to_the_world/"], []], "score": [98, 12, 7, 6, 5]}}, {"q_id": "6tucxs", "category": "Repost", "title": "Heat index. How can it BE 100\u00b0f and FEEL like 110\u00b0f?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlnjg8j"], "text": ["Heat index is essentially a measure of the effect of humidity on a person's perception of temperature. Humidity makes us feel hotter in the summer because the body cools down primarily through evaporative cooling. Basically, the water in/on your skin evaporates in the hot weather and transfers heat from your body to the surrounding environment. This effect is lessened when humidity is high because the air is already saturated, so the water on your body will not evaporate as easily, thus making you feel warmer."], "text_urls": [[]], "score": [6]}}, {"q_id": "6tudqq", "category": "Repost", "title": "Why does grease make paper transparent-ish?", "title_urls": {"url": []}, "selftext": "It often happens when I'm eating something greasy and use napkins or something made of paper, that the paper loses its colour and becomes blurry. Why?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlnkhf4"], "text": ["Light changes direction when entering a different material. Paper makes light go in lots of directions. Adding oil which changes the direction at the same angle as paper reduces the scattering caused by the air/paper interface allowing more light to pass in the same direction."], "text_urls": [[]], "score": [6]}}, {"q_id": "6tugtn", "category": "Repost", "title": "What causes people to talk with a lisp?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlnmch4"], "text": ["> The motht frequently dithcuthed of thethe problemth ith tongue thrutht in which the tongue protrudeth beyond the front teeth. Thith protruthion affectth thpeech ath well ath thwallowing and can lead to lithping. Ankyloglothia or tongue-tie can altho be responsible for lithpth in children - Google"], "text_urls": [[]], "score": [10]}}, {"q_id": "6txdeo", "category": "Repost", "title": "The difference between increasing your heartbeat with caffeine and increasing it with exercise.", "title_urls": {"url": []}, "selftext": "Why is it unhealthy to increase your heartbeat from drinking too much caffeine, but increasing it the same amount during exercise is good for your heart?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlo9l9u"], "text": ["Ahoy, matey! Yer not alone in askin', and kind strangers have explained: 1. [ELI5: Why is cardio exercise good for your body, while using stimulant drugs is bad for it? They both increase your heart rate and make your body work so isn't taking the stimulants just a form of exercise for your heart/body? ]( URL_4 ) 1. [ELI5:Why is it good for you to raise your heart rate through aerobic exercise but not through caffeine, stress, anxiety, etc? ]( URL_1 ) 1. [ELI5: Why is raising your heart rate through exercise good for you whereas doing it via caffeine or cocaine is really bad for it? ]( URL_0 ) 1. [ELI5: Why is exercise that increases my heart rate considered good, but medication and narcotics that increase my heart rate are considered bad? ]( URL_2 ) 1. [ELI5: Why would exercise like cardio stress my heart in a \u201cgood\u201d way when drugs like cocaine stress it in a damaging way? ]( URL_3 )"], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/33dvnd/eli5_why_is_raising_your_heart_rate_through/", "https://www.reddit.com/r/explainlikeimfive/comments/661psu/eli5why_is_it_good_for_you_to_raise_your_heart/", "https://www.reddit.com/r/explainlikeimfive/comments/2ueh9z/eli5_why_is_exercise_that_increases_my_heart_rate/", "https://www.reddit.com/r/explainlikeimfive/comments/1pa8tq/eli5_why_would_exercise_like_cardio_stress_my/", "https://www.reddit.com/r/explainlikeimfive/comments/29zrjj/eli5_why_is_cardio_exercise_good_for_your_body/"]], "score": [3]}}, {"q_id": "6u0b05", "category": "Repost", "title": "Why is water essential for life?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dloxxoo"], "text": ["There might be a form of life that uses something else. But we can only speculate. Water is a unique chemical with many special qualities. It's solid form floats in its liquid form. Its polar nature makes it an excellent solvent. It readily separates into a proton and a hydroxyl group allowing many chemical reactions. Our chemical engineers build distillation equipment that works without water. They build cracking towers which process petroleum. Many chemical reactions must occur without water present. But we are mostly water. It is how life on Earth works."], "text_urls": [[]], "score": [3]}}, {"q_id": "6u15t5", "category": "Repost", "title": "Why can sound get through walls when light can't?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlp38ds"], "text": ["Sounds is a pressure wave. It works by the periodic compression and expansion of molecules in the medium it travels in. Air works fine, water works better, solid materials work even better - generally, the denser a material, the faster sound will be able to travel. So sound can travel through walls because the material the wall is made of compresses and expands to allow the sound wave passage. Light is an electromagnetic wave. For an electromagnetic wave to be able to pass through a material, there needs to not be a mechanism which blocks it. Examples of mechanisms which can absorb electromagnetic radiation are diffraction, where the wave gets spread out by a gap which it passes through (comparable to its wavelength); molecular absorption, where the light is absorbed by the bonds of molecules, causing them to vibrate, rotate, stretch, etc.; and atomic absorption, where a photon of light kicks an electron in an atom up to a higher energy level by being absorbed by that electron. The materials our walls are made of have electronic structures in their atoms and molecules which mean that light is either reflected or absorbed by their surfaces. Glass, meanwhile, has molecules where it's electrons are bound up in bonds that don't have an energy or wavelength comparable to visible light so they won't respond to it. A good rule of thumb for figuring out if something will interact with a particular wavelength of light or not is to see whether their energy/length scales are the same as the light. For example, x-rays diffract between the atoms in crystals because the spacing is a similar wavelength to that of x-rays; many molecules absorb infrared radiation because their bonds lengths are similar to the wavelengths of infrared, and some radio waves will only travel a few miles because their wavelengths mean they diffract around hills and other features if the landscape."], "text_urls": [[]], "score": [3]}}, {"q_id": "6u43zc", "category": "Repost", "title": "Why is eating raw food like steak tartare or sushi okay when we're warned to cook other foods to a minimal temperature so that it's safe?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlprxx6", "dlpqx4f", "dlpr2ut"], "text": ["Some foods are more prone to parasites than others, and (importantly) some parasites are easier to kill than others. Chicken is a good example - salmonella bacteria can be somewhat commonly found in chicken and can infect the meat all the way through. So we take care to cook the chicken well all the way through in order to kill it. Same deal with pork and trichonosis - that can infect the entire muscle, and not just the outside. In contrast, most of the bacteria that commonly settle on steak and lamb aren't usually able to get down inside of the meat (and once they do, the meat goes rotten and it's easier to tell that it's not safe to eat). So it's safer to just sear the outside (killing the outside bacteria) and eat the rest of the meat rare. Fish have parasites that can infest all the way through, but all fish in most countries is required to be quickly frozen as soon as they're caught, which kills the parasites as well. As long as it's eaten fresh so that no new parasites can infest it, it's pretty safe to eat raw. As long as the transportation and kitchen are clean, there's not much to worry about.", "Many meats are (relatively) safe to eat uncooked if handled properly. There is still a risk of contamination and getting sick. Things like chicken and shellfish are rife with salmonella and the odds of getting a rather unpleasant bacterial infection are high.", "Eating raw food has a risk to it though the risk is small. You can take a bite of raw chicken and you will probably not get sick but to reduce the risk to as near zero as possible, it is advisable to cook food to the recommended internal temperature. Proper slaughtering and processing also help reduce the risk"], "text_urls": [[], [], []], "score": [16, 4, 3]}}, {"q_id": "6u4b04", "category": "Repost", "title": "How do some restaurants, particularly diners and Mexican restaurants, afford such large portions?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlpsjuq", "dlptbgc"], "text": ["Because they make food with cheap ingredients. In general the price of your meal is 4-6 times the cost of the ingredients to make it. Mexican food uses cheap cuts of meat (often scrap meats), rice, and beans. The only expensive components are things like avocado or special cheeses and even those are still not extremely expensive.", "Mexican food is largely composed of very inexpensive ingredients, like rice and beans, with inexpensive Meats like chicken cooked in huge batches. Most parts of the meal can be prepared in advance. All these things cut down on price significantly."], "text_urls": [[], []], "score": [8, 5]}}, {"q_id": "6u4u7g", "category": "Repost", "title": "How do cranes get up to higher floors when tall buildings? And then how do they get down?", "title_urls": {"url": []}, "selftext": "I notice that when skyscrapers are being built they move the cranes up as they go, how do they get up there? Once they are done building how do they get back down?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlpxjgk", "dlqe61n", "dlq3tdn", "dlpxg92"], "text": ["URL_0 Simply put, the crane builds itself as it needs to, and tears itself apart as it needs to. It is immensely fascinating to watch (hence why the link is in the beginning). To give it more like an ELI5. The crane is modular, so you can add pieces to the tower as you need, or remove pieces from the tower. As the crane can move these modular pieces onto itself it uses a jack system to raise itself slightly so that the new piece can fit in. Then someone bolts down the new piece and the jack system is raised and then attached to the new piece so it can do it over again. The reverse is used to lower the crane.", "My dad ran tower cranes for 30 years. They call it jacking the crane. There is a piece called the jacking collar that hooks into two sections of the tower and then literally jacks the top section up so that for a little bit of time there is actually a hole into which the crane lifts another section from the ground and the jacking crew inserts the new piece and bolts it in place. They raise the collar up and add more the same way. They normally do around 4-5 sections at a time. It is pretty time consuming and dangerous. He knew guys that got crushed when the collar slipped. There are specific crews that just travel around and do this. They usually work for the crane rental company as almost all cranes are rented for the jobs. They cost several million dollars.", "They \"build\" them. The one I saw was able to lift it's main body section (or whatever) high enough for the workers to add sections to increase its height one section at a time. The legs extend out, lift the crane, workers install more scaffolding like sections, it's able to incorporate this into the entire structure...rinse and repeat. Opposite chain of events to take it back down when done.", "The tower cranes you see for such projects are made out of modular sections. You can add or remove sections as you want. The top part of the crane can move up one section so you can slide a new section under the top, you use the crane to lift the new section into place. Similarly you can anchor the crane to the building at a higher floor and remove the sections under the new anchors. When they are done most of the crane can be lifted down off the building by the crane itself. The last few sections are much easier to get down. For example by using winches or a helicopter."], "text_urls": [["https://www.youtube.com/watch?v=vx5Qt7_ECEE"], [], [], []], "score": [116, 12, 6, 4]}}, {"q_id": "6u52uf", "category": "Repost", "title": "Why are we putting our hands in front of our mouth when in shock?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlpzmad"], "text": ["It is a way of concealing our emotions from others, to avoid showing that we are afraid, shocked or disgusted."], "text_urls": [[]], "score": [8]}}, {"q_id": "6u58dd", "category": "Repost", "title": "Private-Public Key Cryptography", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlq0sse"], "text": ["This is a very common question, and [this Search]( URL_0 ) generates lots of detailed responses. Please Search. It's an encryption system which uses two-part keys for each user. One part is published, for sending messages to the user and the second part is kept secret, for messages from the user. Each message is encrypted using the sender's private part and the receiver's public part. This assures the sender that only the receiver can read it and the receiver that only the sender could have sent it."], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/search?q=public+cryptography&amp;restrict_sr=on&amp;sort=relevance&amp;t=all"]], "score": [3]}}, {"q_id": "6u688p", "category": "Repost", "title": "How do high areas of heat ripple our vision?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlq9d9l"], "text": ["Hot air is less dense than cold air, and light travels through them at slightly different speeds. At the boundaries between hot and cold air, the difference causes light to refract (aka bend) as it passes from one to the other. As the hot air rises and circulates with cold air, the boundaries between hot and cold constantly change as well as does the direction of light passing through. This creates the moving, ripple effect."], "text_urls": [[]], "score": [3]}}, {"q_id": "6u6m0h", "category": "Repost", "title": "Why does the letter 'a' look the way it does in type but often looks differently when handwritten?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlqoqmc"], "text": ["Noice that the written version is the same as the types version minus the hook in top. Well, the written version is just an abbreviated version, because it's easier and faster to write, but they still use the full version on some fonts since it's not any easier or harder for a computer."], "text_urls": [[]], "score": [6]}}, {"q_id": "6ub388", "category": "Repost", "title": "How do all kinds of dogs look so different but are still essentially...dogs ?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlrb9u7"], "text": ["Selective breeding over literally thousands of years, to select for different abilities; hearing, smell, ability to run, ability to dig, strength, power, you name it. Humans naturally diverge based on their geographical location. Obviously nowadays with travel and the world being a much smaller place than it was, and general technology, these things have become less relevant, but this is the reason that more northern (or below the equator, sourthen) people tend to be lighter skinned, and people from hotter more equatorial regions tend to be darker. Dark skin is an advantage in bright powerful sunlight because it protects against sun damage, a natural sunblock. Why isn't everyone dark skinned then? Because if you're in areas where sunlight is weaker (more temperate to cooler regions), dark skin prevents you absorbing enough vitamin D. Which is why people historically from those sort of areas are paler skinned, and the colour tends to vary with the general temperature of the area they're from. Those natural varations have just been exploited with dogs, over a long *long* time selectively breeding for certain traits to accentuate them, and diminish others. It would in theory be possible to do with humans too, breed for height and...well whatever you want, given enough time, but that is obviously an *extremely* morally dubious area of thought. Known, if you're curious, as [\"Eugenics\"]( URL_0 )."], "text_urls": [["https://en.wikipedia.org/wiki/Eugenics"]], "score": [11]}}, {"q_id": "6ubsie", "category": "Repost", "title": "How do torrents work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlrg1oc", "dlrg8of"], "text": ["I would recommend watching [this]( URL_0 ) video, explaining what exactly torrents are and how they work In short, \"seeders\" are people that upload *things* to internet. A \"peer\" is anyone connected and transferring data A \"tracker\" is a server that keeps track of which seeds and peers are in the \"swarm\" (all peers (including seeds) sharing a torrent)", "Basically the way that torrent works is that it has files chopped up into tiny pieces and each is individually and assembled together as it downloads. The magnet link or .Torrent file contains a list of trackers among other information, trackers being servers that negotiate connections between people downloading through torrent. A seeder is a person who has the complete file and uploads it to other users, peers/leechers are people who are still downloading the pieces, but they also upload the parts they have to other users. Anyways, point is that it is a distributed system of downloading files, without having a single server feed you the entire file, you just grab chunks from various other users, both seeders and leechers."], "text_urls": [["https://www.youtube.com/watch?v=EkkFT1bRCT0"], []], "score": [4, 3]}}, {"q_id": "6udtzh", "category": "Repost", "title": "How is lobbying not considered bribery?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlrxce1"], "text": ["Frequently the things of value provided to the government official are not money and nowadays even though some non-monetary bribes are also outlawed there are many ways to disguise the bribe. One fun way is to arrange to have a book written for the politician under his/her name, then buy back thousands of copies with the royalties going to the politician legally (though there are efforts to stop this one too). There will always be ways. A fancy way I particularly like is to arrange fundraisers and otherwise package huge campaign contributions to the government official. This can be done even if he is not running for anything, or is running unopposed. There have even been cases where campaign contributions were made to bribe politicians (in non-elected jobs) who weren't even *planning* to run for anything. Then the candidate can raid the campaign contributions for personal expenses and even, in many cases, totally confiscate the campaign contributions after the campaign is over (even if there never was a campaign). I worked for a long time in an entity where lobbying was in the same division (I was not a lobbyists but in a related and honest function). There was no pretense, internally, that what they are doing was not bribery; it's a joke."], "text_urls": [[]], "score": [3]}}, {"q_id": "6uhfip", "category": "Repost", "title": "after watching my 3 year old play in her imaginary world, what changes in our brains as we move into adulthood that we lose this skill?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlsnqal", "dlsov0g", "dlsnppv", "dlsnrup", "dlss8i1", "dlsr7wn"], "text": ["Follow up question - what do you mean by *lose* this skill? I'm 22, do extensive worldbuilding in my head and have an imagination that can keep track or hundreds of personalities in one world I create in my head. When I commute or go to bed I go through the same thing your daughter does", "Hey, funnily enough I [answered this question for another person with a video a while back]( URL_0 ) If you dont want to watch the video I'll run over the points here too: - We are more in touch with reality as we grow older. The economy, and our limited time on this planet distract us. We need to make sure we can provide for our family and friends, we study and work to make sure we can live a comfortable life. - Social norms also take away from us, we understand we have a role in the world and as adults we believe we shouldn't be seen being \"childish\" and having a very active imagination can be seen as this. I personally dont agree with how people see this as childish at all, I think it's a great character to have. It's different depending on culture though, as we are brought up in a certain way to see adults as responsible, serious hard working individuals. - We care about what other people think, children do not. There have been studies to show that they dont care, they dont see the world the same as us. Kids are a bundle of joy (most of the time!), as we grow older we are much more worried about how people see us. This may be down to the fact that we are hardwired to find a partner and have children. If we dont act in an attractive way, then we may not find a mate. It's pretty blunt to say, but at the end of the day we are animals and our top priorities are survival and breeding. - We are much more busy as adults, as I stated before we are constantly working and our lives get swallowed by work. The majority of people don't live in the now. They live constantly thinking of the future, not paying attention to the here and now. Children are different, they live for the now. They try and enjoy themselves as much as possible. Playing and imagining cool scenarios are examples of this. For example, if a child was sat in a car they'd look out the window and see a blank canvas. They'd imagine a character running along side the car doing all sorts of cool stunts (that's what I used to do). However, an adult may not think like this, they'd think about people, work, debt, schedules etc etc. Hope that helped, and I hope you enjoyed the joke at the end of the video. I usually answer peoples questions through this subreddit in the form of a video and I've been doing it for a year now. My drawing has got slightly better, along with my animation skills. This video is pretty old, but it targeted your question so I thought I'd try and help you out! Have a great day.", "You simply stopped doing it. Not everyone does and those that continue it are still able to do this. They tend to use said skill to write books, write video games, make movies, make tv shows. And in the non-professional realm they write fanfic, picture books as they read them, play table top games, etc.", "I would propose that you simply get smarter. The same idea might pop into your head \"man wouldn't it be cool if a dragon had machine guns mounted on it?\" But then the logical part of your brain would step up telling you how angry a dragon would be, how relatively useless machine guns would be attached to it, etc. If you asked a child \"why does the dragon let you ride it\" the child might say \"We are friends\" but you would ask yourself \"well why are we friends, how could we possibly have met and developed a friendship.\" If you want to go around riding on a dragon doing crazy adventures you basically have to come up with the entire Game of Thrones world in order to satisfy the questions you would have. That kind of thing takes a tremendous mental effort and commitment of time. You have to justify to yourself spending that time on it. However, when those answers are given to you, you will absolutely lose yourself in fantasy for hours at a time: look at video games, movies, or books. Those things really are just guided imaginings.", "In fact we still have that skill, we just don't use it anymore because as we grow older, we adapt to the reality and accept it as it is. As adults we have responsibilities and pressures such as making a living. Most of the adults find daydreaming as silly and distracting. But there are people who still do it as adults, they are writers, actors, movie directors, etc. There are a minority of other adults who do it compulsively, and that condition is called [Maladaptive daydreaming]( URL_1 ). Most people are unaware of this, including mental health professionals. [BBC World News Aug.9.17 story on Maladaptive Daydreaming]( URL_0 )", "We do imagine stuff though don't we? Like I'm always imagining conversations, what I'll do when I get home, what is going on in the head of white nationalists, how many upvotes I will get for this post etc etc. It's an important part of how we plan for the future and understand one another. What I'm saying is our imagination doesn't disappear it just gets used differently."], "text_urls": [[], ["https://www.youtube.com/watch?v=GyfOduzia4A"], [], [], ["https://www.youtube.com/watch?v=CU8oozZKn04", "https://en.wikipedia.org/wiki/Maladaptive_daydreaming"], []], "score": [197, 110, 21, 10, 7, 4]}}, {"q_id": "6uiq52", "category": "Repost", "title": "how did ravens/ pigeons know where to go when released with a message!?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlsxyf9"], "text": ["they only know how to fly home. thus they're called homing pigeons. it's one directional communications. raise a homing pigeon from birth at a location and it always goes back there."], "text_urls": [[]], "score": [4]}}, {"q_id": "6ujok0", "category": "Repost", "title": "Why do babies are born so unprepared for life?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlt61vh"], "text": ["> Wouldn't being a bit prepared for danger a better evolutive advantage? It would, but evolution does not work that way. There is no plan, no one guides it. Evolution just happens and if the result is an improvement it lasts and if it's not it dies off. So there are lots of things that would be beneficial to have if Humans evolved them, but it just hasn't gone that way. Humans have a few advantages over other animals but when it comes to our babies, 2 are in conflict. Ancient humans hunted for food, but we're not as fast as many other animals. We have an advantage over them however, we have stamina. Our ability to walk on 2 legs, plus the way we dissipate heat means ancient humans were able to \"run down\" most animals then just walk up and kill it when it was so exhausted that it could not go on. This \"walking on 2 legs\" this is important. It's much more efficient than 4 legs, but it's not as fast. Su we are better able to use our resources and out last out pray in part because we walk upright on 2 legs. That's an advantage that evolution HAS given us. The next advantage is our brains. Human brains, as compared to the overall size of our bodies are very large in comparison to other animals. Big brains, make us smarter. You could say that the human brain is the single biggest evolutionary advantage that there ever was. Big brains need big heads, because of the way brains grow, a baby is like half head. So, big headed babies and the requirement to walk upright. These 2 factors come into conflict at the pelvis during childbirth. Human women need to give birth to a \"half cooked\" offspring because if they wanted longer the baby's head would be too large to pass through the pelvis. If the pelvis changed it would affect our ability to walk upright. So human babies are born unprepared because that's what needs to happen in order to maintain our 2 other advantages, walking upright and big brains."], "text_urls": [[]], "score": [18]}}, {"q_id": "6ujwt8", "category": "Repost", "title": "Why is water so destructive to electronic devices?", "title_urls": {"url": []}, "selftext": "My wife dropped her phone in a bucket of water for probably half a second and now it's completely ruined. What is it about water that so thoroughly destroys electronic devices?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlt9rz3", "dlt8hwr"], "text": ["Ahoy, matey! Yer not alone in askin', and kind strangers have explained: 1. [Why does water ruin electronics? ]( URL_3 ) 1. [ELI5:What makes electronics break if you soak them in water, even though they are turned off? ]( URL_1 ) 1. [ELI5: why exactly does water hurt electronics? ]( URL_0 ) 1. [ELI5: Why does water ruin electronics? ]( URL_2 ) 1. [ELI5: how exactly does water ruin electronics, assuming that they are turned off after and dried throughly, what damage to hardware is done that is irreparable? ]( URL_4 )", "There are two ways that water can destroy electronics. And both are worse in salt or soapy water. First off the water might conduct electricity better then the air so you might create additional electrical paths. This can overload components that can get more current then they are designed for and destroy them forever. The second and more common as voltages in devices is getting lower and lower is by reacting with the conducting coating on the circuit board and the connectors. You may have observed crystals forming on the terminals of old batteries and you may have cleaned them off to get it to work again. The same thing can happen to circuit boards and may be accelerated by water. But unlike battery terminals there may not be enough material underneath for you to be able to fix it. So if you drop something in water then try as best as you can to turn it off and disconnect the battery. If the water is salty or soapy then soaking it in clean water will help. Preferably distilled water. Then let it dry off in a dry room tempered place. You may have seen suggestions to use rice which will create a dry environment but take care that the rice will not actually be able to enter any gaps or contacts on your device. However a paper cloth may work just as well to create a dry environment."], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/220pei/eli5_why_exactly_does_water_hurt_electronics/", "https://www.reddit.com/r/explainlikeimfive/comments/3uzazd/eli5what_makes_electronics_break_if_you_soak_them/", "https://www.reddit.com/r/explainlikeimfive/comments/y7vsg/eli5_why_does_water_ruin_electronics/", "https://www.reddit.com/r/explainlikeimfive/comments/1p10lb/why_does_water_ruin_electronics/", "https://www.reddit.com/r/explainlikeimfive/comments/2arnx1/eli5_how_exactly_does_water_ruin_electronics/"], []], "score": [3, 3]}}, {"q_id": "6ulvkz", "category": "Repost", "title": "Why is it considered \"wasting water\" when I leave the water running or take a long shower if the water goes down the drain and is recycled at a water treatment plant?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dltnsca"], "text": ["Water treatment isn't free. It costs money to build those plants & energy to operate them. If you're in a place that's got clean water shortages, you can still deplete your clean freshwater supplies faster than nature completes the water cycle to bring it back to you."], "text_urls": [[]], "score": [3]}}, {"q_id": "6umsid", "category": "Repost", "title": "Why do some people get moody when they are hungry?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dltvc12", "dltvra4"], "text": ["Your brain needs enough food to work right. If you don't eat enough, your brain goes weird, which can make people moody. For the 12y/o version: brain function is tied vey closely to blood sugar levels. Believe it or not, there's truth to those snickers commercials.", "When you're hungry, your brain and body aren't getting what it needs. It's similar to sleep deprivation in a way. When someone's sleepy, everything becomes harder for the brain to do, similar to with low blood sugar. It's also believed to be related to serotonin. > [While many factors contribute to this \"Hangryness\", it's believed that a large part of this aggression is caused by a droop in serotonin levels. Serotonin is what is called a neurotransmitter, a specific substance that carries a signal from one nerve cell to another. In this way, the amount of a specific neurotransmitter creates different effects on our body. Serotonin is unique due to the fact that its effects generally are inhibitory. In other words, serotonin reduces sexual behavior, suppresses pain perception, and stabilize moods. Researchers found that making individuals hungry leads to diminished levels of serotonin in the brain, which in turn, made certain parts of the brain weaker than normal (ie the parts that make us behave like humans rather than animals.)]( URL_0 )"], "text_urls": [[], ["https://www.reddit.com/r/explainlikeimfive/comments/22bed9/eli5why_do_some_people_get_incredibly_grumpy_when/cgl8hkv/"]], "score": [4, 3]}}, {"q_id": "6umv1n", "category": "Repost", "title": "Explain to me the fourth dimension", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dltwkxo"], "text": ["You might enjoy these previous posts on the topic: URL_0 URL_1"], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/search?q=4th+dimension&amp;restrict_sr=on", "https://www.reddit.com/r/explainlikeimfive/search?q=fourth+dimension&amp;restrict_sr=on&amp;sort=relevance&amp;t=all"]], "score": [3]}}, {"q_id": "6uo8ax", "category": "Repost", "title": "Why do we make faces when we are doing something that requires more dexterity (i.e fine motor function) than usual?", "title_urls": {"url": []}, "selftext": "This refers to things that include threading a needle, working with miniature things etc.", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dluca49", "dlu9l8g", "dlui6et", "dluf8t1", "dlui6j6", "dlu8myf", "dlumppt", "dlugqoa", "dlumylx", "dluc495", "dluhx5y", "dlug5lh", "dluuq58"], "text": ["It's basically you're involuntarily communicating through your gestures that you are concentrating and don't want to be disturbed. > A prevailing theory regarding the evolution of language implicates a gestural stage prior to the emergence of speech. In support of a transition of human language from a gestural to a vocal system, articulation of the hands and the tongue are underpinned by overlapping left hemisphere dominant neural regions. Behavioral studies demonstrate that human adults perform sympathetic mouth actions in imitative synchrony with manual actions. URL_0", "This has been asked before, [kind of specifically about sticking out your tongue.]( URL_0 ) So...you're beta-testing the Discord video server, eh? ;)", "Daniel Kahneman, a Nobel prize winning psychologist and economist, discovered the brain has two \"modes\", which he calls system 1 and system 2. System 1 is fast, instinctive and emotional; System 2 is slower, more deliberative, more logical, and requires concentration to use. We have both systems because each is fit for a different purpose. When the lion jumps out of the bush, you don't want to sit down and puzzle out a 13-point action plan. ~~These systems can be manually activated~~ You can help activate these systems by smiling and frowning. Smiling activates system 1, and this is thought to be evolutionary selection to help us get along socially -- quick banter, jokes, being in the moment, and paying attention to multiple things. Frowning activates system 2, and this is thought to be evolutionary selection for rumination -- when something is wrong in your life you need to stop and figure out what needs to change. Actually it would be more accurate to say that (like many things in physiology) they're activated in a feedback loop. Using system 1 makes you smile which reinforces system 1 which makes you smile which reinforces system 1, and so on. Similarly, using system 2 makes you frown which reinforces system 2. We stay in system 1 most of the time because it requires very little mental energy compared to system 2, which becomes exhausted quickly. Our body is always trying to put us back into system 1; or more accurately, system 1 tends to automatically answer questions before system 2 ever gets a chance, and it takes deliberate effort to ignore your first instinct in favor of puzzling something out. **tl;dr We frown while concentrating because it helps us maintain our concentration. More specifically, it's a biological feedback mechanism for activating system 2.** Kahneman wrote about the two systems in his best-selling book *Thinking, Fast and Slow*, wherein he also goes into detail on the cognitive biases each system is susceptible to. It's a really good book that can help us catch ourselves in the act, and I'd highly recommend it. You can read a brief summary [here]( URL_1 ), or a more in-depth one on [Wikipedia]( URL_2 ). EDIT: /u/lansaman also posted [a great video]( URL_3 ) on the subject below. EDIT2: NYT also did a [great summary of the work]( URL_0 ), and even gets into some of system 1's cognitive biases, as well as other conclusions from the book on the nature of happiness.", "It's called overflow. Engagement in difficult tasks often causes involuntary changes in not just face muscles but other positional muscles too. Your efforts \"overflow\" into other areas of the body, since your efforts cannot make your hands be more hands... I hope that makes sense.", "A lot of people are talking about faces relaxing, or becoming stonefaced with concentration. What about with something like playing guitar? My whole face has a life of it's own when I hit those full step bends, and it's definitely not relaxed... What's up with that?", "Animating a face requires many muscles to work in tandem - complex stuff. I see it more as the LACK of making a face. Your mind is too focused on the task to even partially care if it's smiling or where your eyebrows are, slumping into a neutral energy-preserving state. But as a perpetual disinterested scowler, I'm hardly a professional in this field.", "There is a term in psychology for this (I forget for know but I'll search for it) but it was observed in young children first. A neuroscientist noticed that when group of children were learning to use scissors for the first time. A lot of them would make the motions scissors do, but with their mouths. It eventually lead neuron recruitment Essentially your brain is recruiting as many relating neurons of that related skill to complete the task successfully I'll look for the term", "Were social creatures. If were making a face its to convey a message. Evolution has led us to the point where these non verbal communications linger despite them not being directly advantageous to survival. In this instance making a face may suggest to onlookers \"this is a difficult task, please act in a way that aids me in performing\" or \"I'm enjoying this, please fuck off\"", "Based on everything that I'm reading here, the correct answer is \"everyone knows but everyone disagrees so really, no one knows at all\". Just like virtually anything to do with diet or nutrition.", "Your brain has a certain amount of resources it can use at once. It doesn't want to waste them controlling unconscious movements when something more important is being done.", "Because we're completely unaware of our bodies. There's a site... lemme find it.. URL_0 that addresses this kind of stuff. I learned about it in acting classes, we did some workshops that addressed unconscious physical behaviors.", "Follow up question, why do we grunt/yell when physically exerting ourselves like by doing a heavy lift at the gym?", "As an expert in involuntary facial movements, I believe it is due to the fact that at least a small amount of our focus goes into not making stupid faces and keeping our tongues in our mouths. If we are forced to use all of our concentration we lose the bit necessary to not look like a goob."], "text_urls": [["http://www.sciencedirect.com/science/article/pii/S0010027715000840"], ["https://www.reddit.com/r/explainlikeimfive/comments/1rcpj0/eli5_why_do_humans_in_moments_of_great/?st=j6jazfse&amp;sh=7ad994c1"], ["http://www.nytimes.com/2011/11/27/books/review/thinking-fast-and-slow-by-daniel-kahneman-book-review.html?mcubz=1", "https://www.theguardian.com/books/2011/dec/13/thinking-fast-slow-daniel-kahneman", "https://en.wikipedia.org/wiki/Thinking,_Fast_and_Slow", "https://youtu.be/UBVV8pch1dM"], [], [], [], [], [], [], [], ["http://www.alexandertechnique.com/"], [], []], "score": [1640, 1338, 757, 95, 20, 18, 15, 13, 12, 7, 6, 5, 3]}}, {"q_id": "6uoed5", "category": "Repost", "title": "why would you put +120fps on a game if your monitor is limited to 60Hz ?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlu70rv"], "text": ["Basically, more fps equals less input lag, which is not important in every game, but makes a difference in some competitive games like CS:GO. Nicely explained [here]( URL_0 )."], "text_urls": [["https://youtu.be/hjWSRTYV8e0"]], "score": [3]}}, {"q_id": "6uotmu", "category": "Repost", "title": "If bad taste is our body's auto-defence against bad/unhealthy food (eg. poisonous/rotten), why does junk food taste so good?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlu9hqa", "dlu96mx", "dlu99to", "dlu9auf"], "text": ["Junk food is not unhealthy. In fact, it has *tons* of stuff our body needs to stay alive. Especially calories. Back when humans were hunter-gatherers, stumbling onto a small amount of high calorie food was a reason to celebrate, because it meant that we were less likely to starve. The problem is that modern society has resulted in high-calorie food being available in almost limitless supply. But our bodies are still hard-wired to treat high-calorie food as something rare. So our bodies are telling us to eat, eat, eat, and when we do we end up eating way more calories than we need, and we get fat -- which is also a survival technique to store excess calories for later famine, and which doesn't do us any good when times of famine or reduced food supply never come, and we just stay fat all the time.", "Because in the quantities found in the wild while our physiology was developing as a species, sugars and carbohydrates were not a danger at all, but in fact, were excellent sources of nutrients. We have made it *so* easy to get these things now that we overeat them, which is the issue, and we have only had a tiny handful of generations to deal with it - and the health issues from eating too much junk food typically manifest later in life than reproductive age so even then it isn't a huge selective factor in reproduction.", "Through most of our history, salt, sugar, and fat were rare. They are very satisfying because they signal our body that we're getting rare nutrients. Now salt, fat, and sugar are everywhere and food manufacturers have learned how to make food so rewarding that we crave more of it.", "Sugar. Sugar was really really difficult to get. Folks graved sugar. Junk food tastes good because of salt and sugar - and other addictive shit. If you must, chicken wrap."], "text_urls": [[], [], [], []], "score": [12, 11, 8, 5]}}, {"q_id": "6up2i3", "category": "Repost", "title": "Cancer", "title_urls": {"url": []}, "selftext": "I obviously know what it is and that it can kill. How though does it actually work and WHY if you have two people with the same lifestyle will one get it and not the other?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlubdxk"], "text": ["Cancer is basically when some cells in your body get the wrong message. Normally, your cells grow and divide in a pretty predictable way, and then they die and are replaced by new ones more or less on schedule. Not cancer. These ones were told to GROW DAMN IT, so that's what they do. They just grow and grow and grow, even in ways they're not meant to or in places they wouldn't normally be. Cancer = abnormal, uncontrolled patterns of cell growth and division. This is basically what tumours are - they're made up of the cells that went batshit. As for *why*...truly, we don't have one clear answer yet. Some people have a genetic component, which is how you can have family histories of a particular cancer. For others, it's because of a lifestyle thing, a side effect of something they've done - lung cancer from smoking would be one, or one of the occupation related cancers like mesothelioma which turns up in builders or related tradesmen who've worked with asbestos. Sometimes it's a side effect of a much more minor medical issue, like how cervical cancer is connected to genital herpes. Some people are just plain unlucky. The reason *why* doesn't really matter. If you've got cells in your body that have started dividing and growing uncontrollably, that's cancer."], "text_urls": [[]], "score": [4]}}, {"q_id": "6usu3r", "category": "Repost", "title": "Where do photons go after you turn off a light that was in the middle of a closed dark box with mirrors on all sides?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlv57o0"], "text": ["All mirrors in the world are imperfect, that means a small amount of the energy a photon holds is converted into heat when striking a mirror's surface. Light moves very quickly so it quickly converts essentially all the light energy to heat one bit at a time. Eventually the kinetic energy in the photons drops low enough that we don't perceive light from them anymore."], "text_urls": [[]], "score": [3]}}, {"q_id": "6ut9vj", "category": "Repost", "title": "Why does the hot water out of the tap look cloudy?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlv96aj"], "text": ["Yarr! Yer not alone in askin', and kind strangers have explained: 1. [ELI5: Why does hot water out of the tap look cloudy. ]( URL_7 ) 1. [ELI5: Why is hot water from the tap always cloudy? ]( URL_0 ) 1. [ELI5: Why does hot water come out white/cloudy from the tap but when I boil cold water it is transparent? ]( URL_2 ) 1. [ELI5: Why does hot water come out of the tap white, but cold comes out clear? ]( URL_5 ) 1. [Why does tap water turn cloudy when it gets hot? ]( URL_6 ) 1. [ELI5: Why does hot water look cloudy sometimes? Why would hot water from a faucet be cloudy, even tho it's crystal clear when cold? ]( URL_3 ) 1. [ELI5: Why hot water out of the faucet sometimes appears cloudy or white in color? ]( URL_1 ) 1. [ELI5:Why is wam tap water not see through? ]( URL_4 ) 1. [ELI5: Why is hot water white right when it comes out the tap? ]( URL_8 )"], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/1pc0t9/eli5_why_is_hot_water_from_the_tap_always_cloudy/", "https://www.reddit.com/r/explainlikeimfive/comments/1oa09l/eli5_why_hot_water_out_of_the_faucet_sometimes/", "https://www.reddit.com/r/explainlikeimfive/comments/1lhuha/eli5_why_does_hot_water_come_out_whitecloudy_from/", "https://www.reddit.com/r/explainlikeimfive/comments/54f3ul/eli5_why_does_hot_water_look_cloudy_sometimes_why/", "https://www.reddit.com/r/explainlikeimfive/comments/57quh9/eli5why_is_wam_tap_water_not_see_through/", "https://www.reddit.com/r/explainlikeimfive/comments/1w7i4n/eli5_why_does_hot_water_come_out_of_the_tap_white/", "https://www.reddit.com/r/NoStupidQuestions/comments/41c483/why_does_tap_water_turn_cloudy_when_it_gets_hot/", "https://www.reddit.com/r/explainlikeimfive/comments/64tk7h/eli5_why_does_hot_water_out_of_the_tap_look_cloudy/", "https://www.reddit.com/r/explainlikeimfive/comments/5a3gq2/eli5_why_is_hot_water_white_right_when_it_comes/"]], "score": [4]}}, {"q_id": "6uvmqg", "category": "Repost", "title": "Bacteria become resistant to antibacterial products but why not bleach and alcohol?", "title_urls": {"url": []}, "selftext": "I understand that some of the bacteria survive the antibacterial products and the ones that survive are more resistant, however why doesn't some bacteria survive alcohol or bleach and become more resistant to those products? For example, if I swap my skin with alcohol even if the bacteria under the swab are all killed when there be some on the edge that would survive but get a partial dose of alcohol?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlvs17d", "dlvp7u2", "dlw5wl5", "dlvpdm9", "dlvqkri", "dlvyvoz"], "text": ["Imagine a bacterium as a big factory, with the bacterium's membranes and cell wall being like the factory's walls and ceiling, the enzymes like the factory's machines and the DNA like a big book of instructions for building the factory. An antibiotic is like sending a saboteur into that factory - maybe to break a critical piece of machinery, or to blow up a structurally important support pillar. The factory could counteract that sabotage by, say, positioning guards that could catch the saboteur (similar to how bacteria may become immune to an antibiotic by mutating an enzyme that can break down the antibiotic. Bleach or alcohol (or also heat) are more like carpet-bombing the factory until just a pile of rubble remains - they damage a bacterium in many different places at once, and in a much cruder manner. That is also why you cannot use them internally to fight an infection - they would cause too much collateral damage to your body's cells.", "It's the mechanism. Antibacterials work internally to disrupt processes and alcohol is external. It's like how you can tolerate my alcohol with repeated exposure but you can't tolerate more fire no matter how much you try", "There is another aspect to resistance that most replies have neglected. Bacteria can and do become resistant to alcohol/bleach/heat/whatever if given enough time. There is a species of bacteria colonising wine vats that can withstand up to 90% ethanol for prolonged time, for example. The problem with most bacteria in a typical setting is that the cost of developing such resistance far outweigh the benefit of having them. Penicillin resistance is taxing enough for bacteria that they lose the natural selection race if there is no such antibiotics around. Alcohol content of over 10% is an extremely rare environment, so any bacteria that develop such resistance will be quickly selected out as well.", "Antibacterials target certain parts of the bacteria. If a single bacterium is born without that part, it will be resistant. Alcohol and bleach, however, just kinda go in and fuck everything up, which is kinda impossible to avoid.", "Picture a working computer. You need to make it stop working. One thing you could do is to pull the plug. It will work, but there are ways around it, like installing an internal power source. Alternatively, you could drop a nuke on it. There's not much that can be done to prevent it. Antibiotics work like pulling the plug, and bacteria can develop adaptations that protect against it. Alcohol and bleach work like nukes. We have to use antibiotics when we can't just drop a nuke - like when the bacteria is inside your body, and drinking bleach, while certainly effective, will also destroy the rest of the body. But your skin is tough enough to take it.", "I know this isn't ELI5, but these are the underlying mechanisms. Bacteria are little guys with cell walls to protect them from the world. When we put something in say a dish to kill said bacteria, they react in different ways in order to protect themselves. When a bunch of a substance (Penicillin or something of the sorts) comes to the bacteria, it has four choices: refuse, spit it out, tolerate, neutralize. This sounds similar to humans with foods, but back to bacteria. The bacterium (only one) crawls over to your antibiotic in question and several things can happen. If the bacteria doesn't recognize it (through a protein on its wall), then it may be absorbed as possible food/pass through the cell wall. If the bacteria has learned that this antibiotic can hurt it and has a protein to identify it before it gets in, the bacteria will ignore the substance. If the bacteria absorbs the substance, then proteins inside can identify it as a hazard and then spit it out (some bacteria even specialize in very efficiently eliminating substances that enter). The bacteria can also recognize the substance, and make a protein to break up the substance so it is no longer a threat. Finally, the bacteria can just learn to tolerate the substance through continued exposure (through a mixture of the previous three methods). So how come bleach/alcohol ALWAYS seem to work? They're such small substances that you can't stop it from getting in, that it can't be broken down further, or if it is broken down then it will become more toxic than the precursor. Other redditors have ELI5'ed this, but a full answer may help some understand it a little better."], "text_urls": [[], [], [], [], [], []], "score": [146, 57, 47, 16, 10, 5]}}, {"q_id": "6uw1ar", "category": "Repost", "title": "Why do we get butterflies in our stomach?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlvtfic"], "text": ["When you get anxious, your muscles (including stomach muscles) tense and become hyper-sensitive as part of the body's fight or flight response. You feel it in your stomach more because there of the vast amount of neurons linking the stomach to brain."], "text_urls": [[]], "score": [6]}}, {"q_id": "6uzpy2", "category": "Repost", "title": "Why isn\u2019t there an autocorrect type thing for coding? Wouldn\u2019t that make things significantly easier than having to go through and manually find an error?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlwlxc4", "dlwm0tz", "dlwm6b3"], "text": ["There are auto correctors for code. But just like with text they correct some orthographic rules and maybe some grammar, they cannot correct if what you code will do what you want, the same way an autocorrector can fix a typo but not the idea you want to communicate.", "What tools are you using? Intellisense (autosuggest) and syntax checking/highlighting is common in most modern development environments. Some will even spell check your string literals.", "There are plenty of tools that are typically called \"intelisense\" (named from the tool in Visual Studio) included with your IDE of choice. These \"auto-complete\" tools lookup possible program objects while you type, and provide suggestions (eg. `spri` - > suggests `sprintf`). They'll also typically underline any piece of text that looks like it *should* be a specific type of object, but the definition doesn't exist (eg. a function call to a function that was never defined). However there are plenty of things that the auto-correct could never understand how to fix. Tools will spit out errors like `missing '}'` with no way to fix it, because there's probably hundreds of valid places you could have meant to put the closing brace. You're telling the compiler `if (something happens) { thing1(); thing2(); thing3();` and it has *no* idea if `something` was supposed to predicate all 3 actions, 2 actions, or just the first one. So it can't do any better than explain `i didn't find the closing }`. Things get even more confusing when it sees `if (something1) { if (something2) { thing1(); thing2(); }` because it again knows only that a missing brace happened, but it doesn't know if the one it does see was supposed to pair off with the first or second if statement."], "text_urls": [[], [], []], "score": [5, 3, 3]}}, {"q_id": "6v181b", "category": "Repost", "title": "Why do we/can we feel the physical pain of a heartbreak or loneliness in our chest? Why do we feel physical pain at all if it is a process that is mostly in our heads?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlwy7nb", "dlwy6tv"], "text": ["Yer not alone in askin', and kind strangers have explained: 1. [ELI5: Why does my chest hurt when I experience heartbreak? ]( URL_5 ) 1. [ELI5: Why is it that when you experience heartbreak there is an actual physical pain in your chest? ]( URL_6 ) 1. [ELI5: Why do we feel heartbreak ? ]( URL_4 ) 1. [ELI5: why do you feel heartbreak and grief so physically? ]( URL_0 ) 1. [Why does my heart actually feel \"heartbroken\" or hurt when im only emotionally affected? ]( URL_2 ) 1. [ELI5 When you are \"heartbroken\" what is really going on chemically in your body? ]( URL_1 ) 1. [ELI5 how does getting your ' heart broken ' happen? Isn't love just an emotion that has nothing to do with an organ that pumps blood? ]( URL_3 )", "I would love to know this too. I remember when I lost my mom, it felt like if I looked down at my chest, I'd see a gaping hole. It felt as if my centre had been ripped out of me. Grief is so powerful, it can feel physical. I wish I could answer your question, but I'm definitely curious about the answer."], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/1zg14e/eli5_why_do_you_feel_heartbreak_and_grief_so/", "https://www.reddit.com/r/explainlikeimfive/comments/2wv1pm/eli5_when_you_are_heartbroken_what_is_really/", "https://www.reddit.com/r/explainlikeimfive/comments/1wgxk5/why_does_my_heart_actually_feel_heartbroken_or/", "https://www.reddit.com/r/explainlikeimfive/comments/3hqr40/eli5_how_does_getting_your_heart_broken_happen/", "https://www.reddit.com/r/explainlikeimfive/comments/6ttxp8/eli5_why_do_we_feel_heartbreak/", "https://www.reddit.com/r/explainlikeimfive/comments/1o324i/eli5_why_does_my_chest_hurt_when_i_experience/", "https://www.reddit.com/r/explainlikeimfive/comments/1tasd3/eli5_why_is_it_that_when_you_experience/"], []], "score": [5, 3]}}, {"q_id": "6v1v1d", "category": "Repost", "title": "Digestion takes about six to eight hours through your stomach and small intestine. Food then enters your large intestine for further digestion. What happens when you eat something bad, and all this is reduced to minutes?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlx480q", "dlx6g9v", "dlx79ud", "dlx8vdx", "dlx9v1t", "dlxbcjg", "dlxgt7y", "dlx9afl", "dlxnyfq", "dlxszwh", "dlx39oj"], "text": ["So your bowels are like a long train track and your food is like a set of cars on the track. Transit time between Point A, your mouth, and Point B, the chute, is a bit flexible but normally operates on a regularly scheduled basis. When you eat, you put cars on the track and send them to Point B. As these cars go to Point B, they lose passengers (nutrients) at various points in the thin tunnel portion (small intestine). The journey isnt complete and the journey has already altered the shape of the car pretty significantly giving a rusty color. Once in the larger portion of the tunnel, the cars are checked for stray passengers and are hosed down a bit so that transition out of Point B isn't so bad. Sometimes, the train cars park juuust outside the gates of Point B so they can exit at the best time for the operator (toilet). Now, all of this goes fucking nuts when you load a bad set of train cars at Point A. The track sensors located everywhere along the track, detect this alien set of cars and sends a distress call to the Supervisor (your brain). The Supervisor wants to handle the situation without having to phone the Manager (your consciousness) about the craziness on the tracks and also wants to make sure you never know it was on the tracks. It has to make a choice now: send it back to Point A violently and somewhat painfully risking tearing the tracks, or send it to Point B as fast as fuck? Depending on where it's located on the track, it'll choose the best route. Let's use the destination Point B. The Supervisor hits the panic button and puts all the train cars that are on the track (in your body) on overdrive. The tunnels are flooded with water and lubricant to speed all the cars up and get them the hell out of there as quickly as possible. Cars collide with each other, and previously well formed cars are just flooded with water and lubricant that they are just a soggy, shadowy reminder of their former glory state. The Media (pain) hears about the car collisions immediately begins filming live the high speed, flooded train cars out of control. They want to knos how an alien set of train cars were put on the tracks and they want someone to pay for such carelessness. The Manager is just watching the horror unfold on Live TV but cannot do anything to stop it, because the Supervisor was deaf and he had not installed a means of communicating with him after hours in the office. I hope this answers your question. TL;DR when you get diarrhea, everything gets pushed out, one way or another. There are no passing lanes. Source: /u/jiggity_gee", "Bad food enters. Stomach is all like \"Red Alert! Battlestations\" and quickly determines \"Abandon ship! Everyone to the escape pods\" and some faux scottish guy is like \"All the escape pods are jammed\" so hammy captain is like \"Can we flood all the escape pods with some extra fluid to lubricate the escape pods\" and the engineer guy is like \"sure but it will be messy\" and then a euridite snob is like \"make it so\" and bam! All the escape pods leave in a hurry.", "This has come up before. I searched for 'digestion' and found these. URL_1 URL_0 Thanks for the down votes people but I wasn't shooting OP down. I was trying to link to more answers.", "Body detects something bad. Wants to get rid of it. A lot of water is spent to get the whole batch going, bowel movement intensifies. Ta da! You are now basically a water-propelled rocket with far to low, yet still impressive thrust.", "What everyone else said, but I wanted to point out that if you have diarrhea literally minutes after eating, is is probably not caused by what you just ate. What you just ate is almost all still in your stomach. 2.5 hours after eating, half the food is still in your stomach. For this reason, symptoms of food poisoning don't usually set in until 6-9 hours after eating something bad. People often think they had a bad meal at a restaurant, when it's really the breakfast or lunch they cooked themselves. Edit: To clarify, yes, I'm mostly talking about food poisoning here. There are other things--lactose intolerance, IBS, etc., that might cause your digestive system to freak out immediately upon eating. Even in those instances, though, the food you just ate is still mostly in your stomach. What is happening in those instances is that your large intestine is being flooded with water. When we are talking about diarrhea, we are mostly talking about things happening in the large intestine. The stuff in the stomach and small intestine remain chugging along at their usual pace (usually).", "Where did you hear about these 6 to 8 hours? BBC did a study with ingestiable sensors and it took about a day and a few hours for a meal to pass from one end to the other.", "The short answer is this: when your body believes it's been poisoned, everything is suddenly on the express line out to get rid of that poison before it's metabolized. You can't really slow down digestion and just hold onto that stuff, so you have to get it out.", "This happens due to the body reacting to foreign or dangerous substance and decreasing water resorption through chlorine pumps to allow it to move through much faster. The body will not wtrempt to absorb nutrients from bad food. When you get diarrhea from a bacteria or amoeba they often damage the cGMP or cAmP receptors leading to chlorine leakage or retention leading to water retention or excretion. This is how both diarrhea and constipation work", "It slows down at the end in your large intestine and/or colon where you reclaim fluid and certain nutrients. Think of it like a cork. Once that goes, things move along much quicker. Gas, does in fact cause pressure. The gas usually just creeps around a turd and your sphincter is like \"sweet, break time.\" With the runs, you get a downward facing champagne bottle. It can't discriminate between air and fluid like it can with air and solid, so you shart.", "FYI, most of the time when you get sick from having eaten something, it's something you ate 12-18 hours ago, depending on how long your digestion takes. Occasionally if you eat something really nasty, your stomach will revel far quicker when the food gets to your stomach. But often you're reacting to something you ate a while ago.", "Your stomach is line a tunnel. Food passing through are cars. Normally with food, these cars pass through the tunnel slowly, steadily, taking their time to pass through the tunnel and be absorbed, broken down etc. During spicy food or food poisoning, this tunnel is flowed and they try to move all of the cars through the tunnel and out asap to minimise damage (aka you shitting it out)"], "text_urls": [[], [], ["https://www.reddit.com/r/explainlikeimfive/comments/wijcl/eli5_if_the_average_digestion_process_takes_about/", "https://www.reddit.com/r/explainlikeimfive/comments/2zyf5a/eli5_why_does_diarrhea_come_so_quickly_when_food/"], [], [], [], [], [], [], [], []], "score": [31873, 2223, 1030, 712, 168, 93, 10, 7, 6, 4, 4]}}, {"q_id": "6v8pdu", "category": "Repost", "title": "In films and TV, how can they make those shots in which the character looks at themselves in the mirror but have the camera not show up in the mirror too?", "title_urls": {"url": []}, "selftext": "In many scenes the camera points at the mirror and the character is moving and we can see both the person and their reflection but not the camera's reflection... how?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlyf86y"], "text": ["Put something in front of the mirror and pretend it's your actor. Now move off to the side. You can see the object and the reflection without being in view yourself. It's just a matter of positioning the camera the right way. They just change the angle of the camera and actor. The actor doesn't actually even need to see his reflection as long as you can. There are other tricks, too. You can disguise the camera, edit it out, or build a set with two identical, reversed rooms and have a look-alike fill in for the actor from behind."], "text_urls": [[]], "score": [15]}}, {"q_id": "6vam0p", "category": "Repost", "title": "Why do many cultures all around the world have Dragons even if they never heard about them from each other?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlyqpk1", "dlyrehy", "dlyqxju", "dlyr6uw"], "text": ["When things like this happen, it's usually either because the idea appeared very early when there was a small number of people or that it arose because of some common experience across the globe. In the former, those people go on to tell the same stories to the generations that follow them, even as populations spread across the planet. As a result, the story becomes widespread. This is one hypothesis to explain why many cultures have stories similar to the story of Jesus: early societies came up with the story, which was then propagated generationally and ultimately spread over a large geographical area as these generations expanded into new areas. In the latter, something is a universal experience, and we may perceive it as a pattern of particular significance. For example, pyramid shaped structures are very stable and convenient when your building technology limits you to stacking things. As a result, many cultures independently discovered pyramids, and they are fairly widespread structures across the globe. Another example here is the great flood, which may have been due to sea level rise as global climate changed early on, before we had a scientific explanation for it. As a result, many cultures speak of a great flood.", "Because dinosaur bones are found pretty much everywhere so it's easy to imagine them being found and myths created to explain them. Voil\u00e0, dragons.", "Do you believe that humans NEVER in all of history before modern times stumbled across dinosaur bones? The legends of dragons most likely stem from early fossil finds coupled with some tall tales from those who possessed specimens.", "Most cultures around the world have been in contact with each other for at least 5000 years. So it is not unthinkable that most dragon myths have the same origin. However the different cultures describe the dragon in lots of different ways so it is possible that there are lots of different creatures in mythology that we today call dragons even if they have different origins. For your statement to be true you need to find two dragon myths that is similar enough to be called the same creature where the two cultures have been separated from the rest of the world for several thousand years. The only such culture groups are the American cultures which in large parts separated from the rest of Europa, Asia and Africa and developed independently. Granted that Vikings likely had contact with the native Americans and Viking ships often had carvings of creatures resembling dragons on them. But even then we do not find many creatures in American culture that resembles the classical dragon. There is creatures that have been described as dragons but apart from being composed of parts from different animals and having scaled skin it does not have many of the traits that is common in dragon myths in European and Asian cultures."], "text_urls": [[], [], [], []], "score": [6, 4, 3, 3]}}, {"q_id": "6vayyl", "category": "Repost", "title": "how did people count years before they startet using the birth of Jesus christ as a time frame reference?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlyt6ya", "dlytdbg"], "text": ["Common methods of reference would be how many years into the reign of the current ruler, or years past some significant event known to their intended audience.", "There really wasn't a standardized system for this before Jesus (or even for a good 800 years after his death); Some ones from the Roman empire include: * The names of the two consuls who held office that year (\"in the consular year of XXX and YYY\") * The time since a Caesar took the throne (\"in the sixth year of the reign of Julius\") * The calendrical epoch of the Olympiad, or counting the time since the last Olympics (\"in the third year of the Eighth Olympiad\") The most interesting one, IMO, that is still used in some form, is the Jewish system that Christian scholars called \"Anno Mundi\" or \"the year of the world\" (according to Judeo-Christian creation myth), which is currently clocked at 5771. Source: URL_0"], "text_urls": [[], ["https://www.quora.com/How-were-the-years-dated-before-Christ"]], "score": [5, 4]}}, {"q_id": "6vc1bo", "category": "Repost", "title": "If we know that Absolute Zero is the coldest temperature possible, why is the hottest temperature possible not known?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlz2tea", "dlz1n8o"], "text": ["There are a lot of wrong answers here, claiming that all molecular motion stops at 0K. *That is not true at all!* Heisenberg's uncertainty principle tells us, that it is impossible for atoms and molecules to have zero kinetic energy. Every bound system has [zero point energy]( URL_0 ). So, what does absolute zero really mean? --- Quantum mechanics tells us that bound particles cannot have an arbitrary amount of energy. Instead, they can only hop between energy levels. And the lowest of these energy levels is still not 0J. *The lowest energy level still has kinetic energy - the so called zero point energy.* Thus, a bound particle must always have motion energy. What absolute zero really means, is that all particles are in this lowest energy state, which is called ground state. Since there is no way a system can have less energy than all its particles being in the ground state, there can be no colder temperature than absolute zero. In fact, due to the uncertainty principle, even reaching 0K is fundamentally impossible. What about a hottest temperature? --- There is no theoretical hard upper limit on temperature. There wouldn't be any mechanism preventing you from adding more and more energy into a system. In some way, of course the total amount of energy in the universe is an upper limit, but that really isn't very descriptive. Some people claim that the upper limit is posed by particles moving at the speed of light. That is *not true*. Even though the speed at which particles can move is limited, their *kinetic energy* has no upper bound. As temperature scales with energy, not speed, the speed of light does not pose an upper limit to temperature.", "Temperature has to do with how quickly the particles are moving. So the slowest is zero movement, right? But that gives us no indication of what the top speed is."], "text_urls": [["https://en.wikipedia.org/wiki/Zero-point_energy"], []], "score": [7, 3]}}, {"q_id": "6vcbxd", "category": "Repost", "title": "Is it a crazy coincidence that the moon perfectly blocks out the sun?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlz4aru", "dlz4ivd"], "text": ["Yes, it's just luck. The Moon is slowly moving away and the Sun is slowly growing. In a million years it won't be big enough for total eclipses anymore.", "Yes. The moon just happens to be at the right distance from the earth such that its size blocks out the almost completely (almost all the time). There are times when it is a bit further than optimal and you get an annular solar eclipse."], "text_urls": [[], []], "score": [3, 3]}}, {"q_id": "6vdpx7", "category": "Repost", "title": "How can animals eat their prey without cooking it and be fine, yet if humans do we would get extremely sick/diseased?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlzfn1n", "dlzfymw"], "text": ["Animals don't save their meat to be eaten later. You could eat a freshly-killed deer or something raw as well, provided it doesn't have parasites. But when you bring it home to eat later, bacteria start growing on it. You have to cook it to make it safe again.", "We eat raw meat all the time (Sushi, steak tartare). It has to be fresh, with no diseases or bacterial growth. Animals are exactly the same. The ones that eat roadkill and other already-dead animals are resistant to the microbes on the old dead meat."], "text_urls": [[], []], "score": [6, 3]}}, {"q_id": "6vdx60", "category": "Repost", "title": "Why do giant characters in movies and tv shows seem to move in slow motion rather than at normal speed?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlzi9ns"], "text": ["Something that is far away from you looks like it's moving slowly, even when it isn't. Think of watching a plane move across they sky; it's going 500mph, but seems to crawl across your view. A giant who's far enough away to fit on the screen will be moving fast, by virtue of being huge, but will still seem to move more slowly because they're further away. Also, it's just a visual trick/cue used to add perceived mass and size to something when you aren't actually there to see it in 3D with proper perspective to the things around it."], "text_urls": [[]], "score": [10]}}, {"q_id": "6vf42k", "category": "Repost", "title": "How do they construct underwater tunnels?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlzrnek"], "text": ["According to google \"To use this method, builders dig a trench in the riverbed or ocean floor. They then sink pre-made steel or concrete tubes in the trench. After the tubes are covered with a thick layer of rock, workers connect the sections of tubes and pump out any remaining water.\""], "text_urls": [[]], "score": [4]}}, {"q_id": "6vf75w", "category": "Repost", "title": "Why do we consider gold valuable?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dlzry3l", "dlzw7ld"], "text": ["Gold is one of the most maleable, attractive and useful metals in the world. In antiquity it was praised for its luster, its shine and its beauty. It was molded into jewelry, used for decoration and used as a luxury item. In ancient times, it was used as currency, stamped with faces and shown to the world and born as a sign of wealth in a nation. Gold was the currency that made the world turn and was internationally turned to as the \"gold standard\" for international trade along with local currencies like Rice bundles, Wheat bundles and animal trades. In modern times, Gold is used in many applications that range from textiles to electronics. Being both maleable and able to withstand massive abuse without destruction, Gold makes a wonderful plating element and beautifying agent for art, decor and embellishments. As a product in science it conducts heat and electricity, and can be made very, very small in size to inhabit spaces no larger than the width of a hair as a conductor or plate items to be a heating element. Gold is more prolific than many other elements also because of its lack of reactable components. Gold is very hard to dissolve and doesn't bond easily to other things, where Iron or copper bond freely with hydrogen and oxygen to form compounds and ions that tarnish the surface and ruin it's uses.", "Yer not alone in askin', and kind strangers have explained: 1. [ELI5: why is gold so much more valuable than silver? ]( URL_4 ) 1. [ELI5: Why is gold so valuable? And why is it more valuable than other metals, like silver? ]( URL_0 ) 1. [ELI5: Why is gold valuable? Also, why was gold important to ancient civilizations? ]( URL_3 ) 1. [ELI5: Why is gold valuable? Especially during the Gold Rush. Can it be used for something? ]( URL_7 ) 1. [ELI5 Why is gold and jewels considered so valuable? ]( URL_2 ) 1. [[ELI5] Why is gold so valuable? ]( URL_8 ) 1. [ELI5: Why is gold so valuable to the world? ]( URL_9 ) 1. [ELI5: How did gold go on to become so valuable? ]( URL_6 ) 1. [ELI5: Why is gold worth so much money in modern times? ]( URL_5 ) 1. [ELI5: Why is gold so valuable? ]( URL_1 )"], "text_urls": [[], ["https://www.reddit.com/r/explainlikeimfive/comments/1utlb8/eli5_why_is_gold_so_valuable_and_why_is_it_more/", "https://www.reddit.com/r/explainlikeimfive/comments/535k5x/eli5_why_is_gold_so_valuable/", "https://www.reddit.com/r/explainlikeimfive/comments/3uds0b/eli5_why_is_gold_and_jewels_considered_so_valuable/", "https://www.reddit.com/r/explainlikeimfive/comments/6hqho6/eli5_why_is_gold_valuable_also_why_was_gold/", "https://www.reddit.com/r/explainlikeimfive/comments/5mnx11/eli5_why_is_gold_so_much_more_valuable_than_silver/", "https://www.reddit.com/r/explainlikeimfive/comments/1mhujj/eli5_why_is_gold_worth_so_much_money_in_modern/", "https://www.reddit.com/r/explainlikeimfive/comments/42q0ir/eli5_how_did_gold_go_on_to_become_so_valuable/", "https://www.reddit.com/r/explainlikeimfive/comments/3i1paa/eli5_why_is_gold_valuable_especially_during_the/", "https://www.reddit.com/r/explainlikeimfive/comments/3qcvxj/eli5_why_is_gold_so_valuable/", "https://www.reddit.com/r/explainlikeimfive/comments/2s2k4d/eli5_why_is_gold_so_valuable_to_the_world/"]], "score": [8, 3]}}, {"q_id": "6vg6si", "category": "Repost", "title": "Does getting 8 hours of sleep broken up throughout the day give you the same physical rest as sleeping 8 hours straight?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dm00wuz", "dm0dle7", "dm0be4e"], "text": ["The short answer is yes - There are a few different \"alternative\" sleep cycles out there. One is the Uberman cycle, where instead of taking a long 8 hour nap, you take 20 minute naps every 4 hours for a total of 2 hours per 24 hours. The idea is to get your body trained to reach REM sleep quickly, as that is when your body rests and repairs itself. In a standard sleep schedule, it may take your body a few hours to reach REM. There haven't been really any side effects reported, although data is limited. I did this for about 6 months and I felt great and well rested. The amount of time I had everyday was incredible. The only thing is that school and work tend to fit around a normal sleep schedule, so it makes it difficult.", "This guy tried polyphasic sleep for an extended time: URL_0", "While it's the most famous polyphasic sleep style, the \u00dcberman was suggested by a woman in a forum who claimed to have done that during her university times. For really looking into it you should start with something easier like the Everyman or a simple biphasic schedule."], "text_urls": [[], ["https://www.stevepavlina.com/blog/2005/10/polyphasic-sleep/"], []], "score": [80, 6, 6]}}, {"q_id": "6vga1c", "category": "Repost", "title": "How do some companies like Hooters get away with only hiring a certain demographic, in this case women, for employment when companies are supposed to be equal opportunity?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dm01i29"], "text": ["BFOQ: Bona Fide Occupational Qualification. To be a \"Hooters Girl,\" one must first be a girl. They hire males to bartend, bus tables, cook, clean and manage, if any are to apply and be qualified."], "text_urls": [[]], "score": [3]}}, {"q_id": "6vipz2", "category": "Repost", "title": "Why do we have dominant hands (feet, eyes etc...)?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dm0puiq", "dm0izpo", "dm0tybi", "dm0yw91"], "text": ["Imagine something flying towards your head. It's quicker to not have to decide which hand you put up to block your head. Instead you usually put up your dominant hand.", "To save brain space. Having both limbs be dominant doesn't offer enough of a benefit to justify the increased use of resources in the brain.", "IANAS but based on what I've seen it's a sort of random roll of the dice of your brain. Your brain essentially chooses a hand based on need when you're learning very basic motions and actions as an infant, those skills grow, muscle memory sets in. This accounts for the random variation of mixed tasks, not quite being ambidextrous, but some actions are done with the right hand and some with the left, enough to question the actual \"dominance.\" For example I am one of two members of my family (immediate and extended) who writes with their left hand. However, I play all sports as right handed person would EXCEPT for throwing (I throw left handed). This is all anecdotal but given the number of anecdotes I can personally think of, I would put money on it being a developmental roll of the dice.", "I believe this question was asked here sometime before. Let me try finding it. There were some great answers there. Edit - Here it is URL_0"], "text_urls": [[], [], [], ["https://www.reddit.com/r/explainlikeimfive/comments/2s8rma/eli5_why_do_we_have_a_dominant_handfoot_instead/?ref=share&amp;ref_source=link"]], "score": [48, 26, 11, 4]}}, {"q_id": "6vjoja", "category": "Repost", "title": "How can a Food have 0 Calories?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dm0p532", "dm0tc5u"], "text": ["1. The amount of calories food is the amount of energy your body can extract from it. Some food doesn't contain any usable energy, for example water or salt (the body still needs them, but not for energy). 2. In the US, food companies are allowed to mark certain items as having 0 calories if they have less then a certain amount per serving. For example Tic-Tacs have less than 0.5 grams of sugar per serving (which is one mint), so they can say they have 0 calories.", "Yarr! Yer not alone in askin', and kind strangers have explained: 1. [ELI5: How Can Something Be 0 Calories? ]( URL_2 ) 1. [ELI5: How can a drink have 0 Calories? Does that mean it gives no energy when you drink it? ]( URL_5 ) 1. [[ELI5] - How is it possible to make \"zero calorie\" food? ]( URL_0 ) 1. [ELI5: How can some drinks/foods be labeled as 0 calories? ]( URL_6 ) 1. [ELI5: Why do things with 0 calories have a \"serving size\"? ]( URL_1 ) 1. [ELI5: How can pickles have 0 calories per serving? ]( URL_3 ) 1. [ELI5: How can a food product contain zero calories? ]( URL_7 ) 1. [ELI5: How Does Diet Soda Have 0 Calories? ]( URL_4 )"], "text_urls": [[], ["https://www.reddit.com/r/explainlikeimfive/comments/j4xs0/eli5_how_is_it_possible_to_make_zero_calorie_food/", "https://www.reddit.com/r/explainlikeimfive/comments/2giudu/eli5_why_do_things_with_0_calories_have_a_serving/", "https://www.reddit.com/r/explainlikeimfive/comments/6h281d/eli5_how_can_something_be_0_calories/", "https://www.reddit.com/r/explainlikeimfive/comments/4mij54/eli5_how_can_pickles_have_0_calories_per_serving/", "https://www.reddit.com/r/explainlikeimfive/comments/3pdt47/eli5_how_does_diet_soda_have_0_calories/", "https://www.reddit.com/r/explainlikeimfive/comments/359ufx/eli5_how_can_a_drink_have_0_calories_does_that/", "https://www.reddit.com/r/explainlikeimfive/comments/37ghac/eli5_how_can_some_drinksfoods_be_labeled_as_0/", "https://www.reddit.com/r/explainlikeimfive/comments/267z7j/eli5_how_can_a_food_product_contain_zero_calories/"]], "score": [15, 8]}}, {"q_id": "6vju2g", "category": "Repost", "title": "Why do strong smells linger in a room even after the source of the smell is gone?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dm0qn31"], "text": ["Your sense of smell is nothing more than specialized nerve cells in your nose reacting to particles of matter in the air. When you smell a flower, for example, you are breathing in pollen from that flower which stimulates your nasal cells and registers as the smell of a flower. Smell lingers in a room because there are still particles in the air from the source lingering around in the air for your nose to register."], "text_urls": [[]], "score": [4]}}, {"q_id": "6vlvp8", "category": "Repost", "title": "How do sites, like Youtube, get ads to load instantaneously but I have to wait for the video to buffer?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dm1ajp4", "dm17waz"], "text": ["To blow your mind more: not only is that ad loading \"instantly\", but in the milliseconds before you see it, your personal tracked information is being uploaded/read in an online ad market, and thousands of ad placement bots are bidding on the right to show you their ad. That space may get hundreds of bids before the winner is selected and that particular ad shown. It's even more complicated than all that, but I paraphrased.", "Ad video data is placed at higher priority than content videos. Both in streaming pipeline as well as storage access."], "text_urls": [[], []], "score": [35, 26]}}, {"q_id": "6vpchr", "category": "Repost", "title": "Why do we tend to walk when talking on the phone?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dm1zeux"], "text": ["\"When we go for a walk, the heart pumps faster, circulating more blood and oxygen not just to the muscles but to all the organs\u2014including the brain\". So it seems walking makes you smarter when answering that job interview call, or when your girlfriend asks where you are right now. ( URL_0 )"], "text_urls": [["http://www.newyorker.com/tech/elements/walking-helps-us-think"]], "score": [5]}}, {"q_id": "6vq7mk", "category": "Repost", "title": "How did the first of ancient travellers communicate with people from a different part of the world, without knowing their language?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dm243iu", "dm2414b"], "text": ["Like we do today, with gestures, pointing, and drawing. If I'm dropped in a foreign country and need to communicate, the first thing is to see if they can speak or understand my language, however unlikely. Next is pictures, they really are worth 1000 words, if I draw a picture of a steak and gesture to my mouth like I'm eating then 99% of the time the fact that I'm hungry will be communicated. The other 1% I have just insulted his mother and he takes my head off, but still communication with out knowing the language.", "> without knowing anything it's almost impossible to learn a new language. Not at all. After all, every single person on Earth has learned at least one language without knowing anything. It's how children lean their native language(s). As an adult, I point to a tree and say \"tree\". You point to the tree and say \"arbre\". Now we each know what the word for tree is in our respective languages. Repeat that for common objects, and by miming actions, and you get a good base of nouns and verbs. Throw in some adjectives (you point to several red things and say \"rouge\", and now I know your word for red), and you've got enough of the language to be able to communicate."], "text_urls": [[], []], "score": [8, 8]}}, {"q_id": "6vqle6", "category": "Repost", "title": "how can time go faster on a different planet?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dm268wi"], "text": ["Because time and space can be twisted by huge masses (or high speed can change how they effect us). The gravity and blackholes are the proof ( also there are theories of scientists such as Einstein). If you wonder the gravity is not like how oppsite sides attract each other. The gravity is the space we are in itself being pulled by a huge mass."], "text_urls": [[]], "score": [4]}}, {"q_id": "6vr8tf", "category": "Repost", "title": "Why do some Countries use 240v and some use 120v for appliances?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dm2bfvi"], "text": ["All countries use high voltage for transmission but different levels of transformer to lower the voltage. Its more expensive to step down to 110 or 120v so 3rd world use 220v or 240v for non industrial use"], "text_urls": [[]], "score": [3]}}, {"q_id": "6vta2q", "category": "Repost", "title": "What happens when you 'pull a muscle'?", "title_urls": {"url": []}, "selftext": "And what is a muscle 'knot'?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dm33v1g", "dm2xfmq"], "text": ["Ahoy, matey! Yer not alone in askin', and kind strangers have explained: 1. [ELI5:What actually happens when you \"pull\" a muscle? ]( URL_0 ) 1. [ELI5 What is the difference in a muscle strain/pull and normal fatigue from working out. Why does one heal so much faster. ]( URL_1 ) 1. [ELI5: say you pull a neck muscle and now it hurts to turn your neck after a certain extent that causes you to stop turning. is this because your neck physically cant turn anymore and youre trying fighting it, or does the pain alert the body to stop before more harm? ]( URL_2 )", "And how to resolve it? I pulled my back muscle front squatting 30mins ago."], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/1nmj8s/eli5what_actually_happens_when_you_pull_a_muscle/", "https://www.reddit.com/r/explainlikeimfive/comments/5nv2eb/eli5_what_is_the_difference_in_a_muscle/", "https://www.reddit.com/r/explainlikeimfive/comments/59vym5/eli5_say_you_pull_a_neck_muscle_and_now_it_hurts/"], []], "score": [5, 3]}}, {"q_id": "6vwyb9", "category": "Repost", "title": "Why is someone recording themselves talking about a murder they committed a confession, but at the same time rappers and others in the music culture talk about murder and drug use constantly in their music with no negative repercussions at all", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dm3makp", "dm3mg73", "dm3m8nl", "dm3mlro"], "text": ["Bobby Shmurda actually gave info towards crime and gang related activity police were looking into in his music and it was used to help build a case lol. So it\u2019s not necessarily without any consequences, especially if what you say can incriminate you of a particular open case", "There are two factors at play: 1. specificity. That is, does the confession/song describe a specific illegal act within the scope of the jurisdiction and statute of limitations. For example, if Johnny Cash says he \"shot a man in reno just to watch him die,\" which man? When? If Johnny Cash instead sang, \"While traveling in Reno on or around January 4th, 1985, I shot a man named Jim Fuller, who was wearing a red shirt at the time, with a .32 pistol then dumped his body in the river, just to *watch* him die\" and the police confirm that a man named Jim Fuller was found dead in a river in Reno due to a gun shot would on January 6th 1985, that would certainly be admissible evidence. Likewise, if a confession was too general, (\"I killed a lot of people then ate them\" \"what people?\" \"Just people, random people\" \"when?\" \" you know, over time\" \"where?\" \"all around\") there's no **specific** crime to tie it to. 2. actually happened and is possible. If Johnny Cash confess to, or sings about, killing Jim Fuller (as above) but there's no evidence that a Jim Fuller died in Reno on or about January 4th 1985 due to a gun shot wound, or Johnny Cash was in LA at the time, it's a moot point. Likewise, if I confessed to assassinating Kennedy, it doesn't much matter as I was not alive at the time.", "There is a significant difference between the freedom to express oneself through the art medium of music, and actually confessing to commiting a crime. 'I shot the sheriff' is a wonderful example.", "A person recording themselves talking about a murder they committed is not a confession unless they're making a sworn statement. It does, however, give a reasonable excuse for police to investigate them, maybe even make an arrest while they search for evidence. Artistic expression (and freedom of speech) allows people the right to say just about anything they want. If they're just making vague statements (I shot a man in Reno just to watch him die), the police have nothing to go off of. In my example, all they have is that someone got shot in Reno. Without a name, a body, a murder weapon, a time, a date, they don't really have anything to go off of."], "text_urls": [[], [], [], []], "score": [4, 4, 3, 3]}}, {"q_id": "6vxz1k", "category": "Repost", "title": "What is the \"resolution\" of the human eye? It is possible to create a camera with a resolution higher than the human eye? If so, how would we perceive the photos it takes?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dm3ub40", "dm3u9q7", "dm3ur48"], "text": ["I think first we have to define what we mean be \"resolution\". The reason being that the retina of the eye is not the same across all of it: we have a fovea - a small area of tightly packed light-sensitive cells in the centre of the retina. When we look at something, this is where the image is sharpest for us (This part is about 16Mp), with the image sharpness quickly falling off toward the edges of the retina. However, we can move our eyes to \"scan\" a scene (with our head being still). If you were to calculate the total Mp of this \"scanned\" scene using the fovea as your base, it would apparently add up to something like 576Mp! Although this sounds unbelievably high-resolution, there are cameras that can top this. They are called \"scanning cameras\" and essentially they are a high-res scanner with a lens mounted in above the plattern, much like the old \"bellows cameras\" of yesteryear, but with a scanner in place of a glass plate. These can scan images of over 1Gp! VSauce has a great video which breaks it down and explains it much better than me! URL_0", "Why are empty threads showing up on the front page? This makes no sense.", "The resolution of the human eye depends on how far away an object is. You will notice more detail from a 1080p screen (1920x1080 pixels) on a smart phone placed 10 inches from your face, than from a 1080p TV located far away from the couch you are sitting on. The human eye has some major differences from a camera. The light sensing part of our eye, the retina, has a very high concentration of colored-light sensing cells (this is similar to single pixels in a camera sensor) in the very center of our vision which falls off quite rapidly. This high resolution in our visual centers is why it is easy to notice detail in the center of our vision but not off-center. In contrast, a camera sensor has uniform pixel spacing on their sensors so they have similar resolution throughout the image they generate. If we assume we are just talking about the high resolution from the very center of our eye (average 147,000 cone cells per square mm), then we have a 655.6 pixels per inch (PPI) resolution at 10 inches (smartphone distance), 273.2 PPI at 2 feet (laptop, computer monitor distance), and 96.0 PPI at 5.7 feet (TV distance). Source: URL_1 It's very possible to create a camera with higher resolution than the human eye. A camera includes the lenses. If you've ever looked into a microscope, you're looking at higher resolution than the human eye since you can see things not possible with the naked eye. Replace your eye with a camera sensor, and you can generate magnified images due the lenses collecting light from a small area and expanding it. We can clearly see images of high resolution microscopy image and other imaging methods. They just expand the size of the image to something we can see! Going the other way, telescopes let us see further than the resolution of our eye. What looks like tiny dots in the sky get expanded to planets, stars, and galaxies with telescopes. Now, if you are talking about having a camera sensor better than the human eye, we have done that too. We just need a camera sensor with a higher pixel density than 147,000 pixels per square mm. Canon has already done this with a 418,000 pixels per square mm sensor: URL_0 . EDIT: Should be pixels per square mm instead of PPI in the last paragraph."], "text_urls": [["https://youtu.be/4I5Q3UXkGd0"], [], ["https://www.cnet.com/news/canons-250-megapixel-sensor-powers-eagle-eyed-camera/", "https://en.wikipedia.org/wiki/Fovea_centralis#Angular_size_of_foveal_cones"]], "score": [7, 4, 3]}}, {"q_id": "6w1dz6", "category": "Repost", "title": "If monopolies are illegal, why are ISP's allowed regional control over huge areas so there is no competition?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dm4l3na"], "text": ["> If monopolies are illegal They're not illegal. Businesses are allowed to be monopolies as long as they follow certain rules. the biggest rule is that they cannot prevent competition. So in your case, Century Link owns the cable running to your house, so if another company wanted to compete, they'd have to lease lines from century link and then sell you century link, but under their name (which will cost more than century link)."], "text_urls": [[]], "score": [5]}}, {"q_id": "6w3qc9", "category": "Repost", "title": "How does the blowing part of CPR work if we are really just putting CO2 in their lungs?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dm548kg", "dm5493l", "dm54912", "dm55vqj"], "text": ["Only a small portion of the oxygen that we inhale gets replaced by carbon dioxide. When you exhale, there is still plenty of usable oxygen left in the breath you took. It's certainly a lot more than the nothing that they are getting otherwise!", "What you exhale is primarily oxygen rather than CO2. (It's mostly nitrogen, actually.) You don't use all of it up when you breathe in. In an enclosed space with a limited amount of air the percentage of CO2 in the air would just gradually rise. So when you perform CPR, you are blowing oxygen into their lungs and helping it circulate throughout the body. In a hospital setting, sure, it's better to have a nice feed of air highly saturated with oxygen--but what you do in CPR is a lot better than nothing.", "Your lungs do not process most of the oxygen that goes into them generally. There is still a large amount of oxygen in exhalation.", "Inhaled and exhaled air are both 78% nitrogen. Inhaled air is about 21% oxygen and minimal CO2, while exhaled air is maybe 14-18% oxygen and 4-5% CO2. By comparison, while the air in certain inhabited parts of Peru or Tibet is still 21% oxygen, the air pressure is only 55-60% of what it is at sea level. On top of Everest, we're down to 30% of sea level pressure. And sure, that excess CO2 isn't ideal, but when the alternative is \"literally no breathing at all,\" exhaled air starts to look pretty good. Big picture, though: The blowing part of CPR is way less important than chest compressions. The current rules for non-healthcare providers are to do compressions only, because breaths are confusing and kind of gross. What matters most is consistent and deep compressions given fast enough. Even bigger picture: CPR is for people who are pretty near death. Outside a hospital, 10% will survive another month; inside a hospital, maybe 20% will leave the hospital alive."], "text_urls": [[], [], [], []], "score": [18, 8, 3, 3]}}, {"q_id": "6w4s4r", "category": "Repost", "title": "what exactly is fire?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dm5c42z"], "text": ["Hot gas. There is a principle in physics called black body radiation. It says that if you heat up anything enough, it will begin to glow in visible light. This is why a hot iron glows red/white. This is why fire glows as well. The chemical reaction making the fire makes the heat, the heated gas makes the light."], "text_urls": [[]], "score": [6]}}, {"q_id": "6w4sme", "category": "Repost", "title": "how come we never remember falling asleep?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dm5c8uw"], "text": ["Exactly this is know as Sleep-related retrograde amnesia and here is a simple explanation: > The occurence of sleep appears to close the gate between short-term memory and long-term memory. All information in short-term memory storage at the onset of sleep apparently fades away. Accordingly, although one is unequivocally aware of the environment (perceiving) before falling asleep, these perceptions are usually lost from memory because they are not transferred into more permanent memory storage. > [Source]( URL_0 )"], "text_urls": [["https://www.amazon.com/Stanford-Sleep-Book-William-Dement/dp/1495119467"]], "score": [7]}}, {"q_id": "6w53mp", "category": "Repost", "title": "How come when, in the Middle Ages, people drank ale/beer instead of water because the water was too contaminated to drink yet they didn't all have foetal alcohol syndrome?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dm5dka8", "dm5im68", "dm5ec2i"], "text": ["The 'beer' they drank was not like the beers of today. It was probably around 2% alcohol. It also wasn't the only thing they drank by a long shot! You might want to check out /r/Askhistorians, as I know I've seen this same question there. Here, for example, is a nearly identical question: URL_0", "1) They drank weaker beer most of the time. The kind of beer that drank a lot was called morning beer, small beer, and other names. It was roughly half the alcohol content of modern beers, and a third or quarter of some of the stronger ones today. 2) They likely did have fetal alcohol syndrome. The infant would have likely just been among the large number of infants that died. The thing to remember is that just because an illness does not get a diagnosis and name till modernity does not mean it did not exist in history or that it exists more now. It just means that we did not know what it was and either called it nothing or called it something else.", "The entire \"drinking beer instead of water\" thing is a myth. Beer isn't strong enough to kill bacteria, so they needed to get clean water anyway. In many European villages, you'll still find the remains of wells that they used to get perfectly clean drinking water, usually located in some sort of gathering place in the middle. In some places, ground water was even shallow enough to just dig a well for every home. They didn't just drink the water from dirty streams, ponds or puddles unless they didn't have a choice."], "text_urls": [["https://www.reddit.com/r/AskHistorians/comments/34535e/if_people_drank_beer_all_day_in_the_middle_ages"], [], []], "score": [26, 14, 3]}}, {"q_id": "6w5b9y", "category": "Repost", "title": "Why do trips seem to last longer while going than while coming back?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dm5i5uo", "dm5pe0x", "dm5hmzt"], "text": ["I feel like it's more because of the anticipation/ possible fear of actually reaching your destination. After you arrive and do what you're there to do I'd say the journey back to where you came from is spent more thinking about what you did. Example: An 8 year old on its way to Disneyland (no sponsorship intended) all excited and hyper thinking about all the things it'd do so the anticipation is killer. But I'm not a psychologist \ud83e\udd37\u200d\u2642\ufe0f", "I read about this on Lifehacker. Here is the link to the source article on Washington Post. URL_0", "I encountered this effect while doing longer marches. If you know the area your are travelling through it seemed to take less time."], "text_urls": [[], ["https://www.washingtonpost.com/news/wonk/wp/2015/06/11/scientists-have-discovered-why-the-return-trip-always-feels-shorter-than-the-trip-there/?utm_term=.128f8dcfff5e"], []], "score": [9, 3, 3]}}, {"q_id": "6w71pa", "category": "Repost", "title": "Does taking medicine that relieves symptoms (cough syrup, aspirin, etc.) help or hinder the body to overcome its ailment?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dm5uamy"], "text": ["It depends. Taking Tylenol or Aspirin to stop a fever hasn't been shown to make you sicker any longer. If you have a cough because of irritation and frequent coughing makes it more irritated, then suppressing the cough actually helps. For most people, a cough is just part of an acute illness and suppressing the cough doesn't make a difference except help you feel better. For people with chronic lung diseases, sometimes making the cough more effective will help clear out their lungs and suppressing the cough is *bad.* For most people in most situations, taking cough medicine or Tylenol or NSAIDs for fever will not help or hinder you getting over the problem. Keep in mind this is just for symptom control. Other medications are obviously very important and do good stuff. Even Aspirin, when it's used for it's antiinflammatory properties or its antiplatelet properties (and not just fever/pain) helps a great deal."], "text_urls": [[]], "score": [3]}}, {"q_id": "6w7w96", "category": "Repost", "title": "How much money is being made from the Floyd Mayweather vs. Conor McGregor fight/event? Who is that money going to?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dm5zrt6", "dm5zf56"], "text": ["Mayweather is guaranteed $100MM, McGregor $30MM. The event is sold out, though I don\u2019t have revenue numbers for that. Tomorrow (or maybe next week) PPV numbers will be released, which will be a major chunk of revenue, at ~$100 per household, and thousands of dollars for every bar and restaurant that shows it (actual cost is based on the number of seats in an individual establishment). I don\u2019t know how proceeds are split but ticket sales and PPV are where most of the money will come from. Edit to add Mayweather is his own promoter (I believe) and UFC (or one of their entities) is promoting McGregor.", "depends on who you ask... tomorrow we migh know. mayweather is expecting about 400 mill, mcgregor will be paid 100 mill afaik. the ufc is surely up for some grabs, but i dont know if thats for certain. the fight is put on by mayweather productions, so most of the profit will go to floyd, but he also had to pay for the venue and so on"], "text_urls": [[], []], "score": [4, 3]}}, {"q_id": "6w8fhn", "category": "Repost", "title": "How did last names become a thing and how were they chosen?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dm63e2n"], "text": ["First names are quite easy to understand as people need a way to distinguish each other in a family or a village. But as communities grew larger you could get people with the same name or you may not know the first name of everyone. However this was not a big problem as you could just use a descriptive word or two. For example William the Brownsmith, George from Hilltown, John Peter's son. But as communities grew larger and people moved to big cities these descriptions became less of a description and more of a name."], "text_urls": [[]], "score": [12]}}, {"q_id": "6w8nwu", "category": "Repost", "title": "If we are clean after taking a shower how exactly do our towels get dirty?", "title_urls": {"url": []}, "selftext": "My niece was asking this question last night. I didn't know the answer to give. Her mom seemed completely uninterested as usual. So I would like to supply her with an answer. Any help is appreciated.", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dm64xu2", "dm650gh", "dm6eg6f"], "text": ["When you dry yourself off, you're rubbing off dead skin & natural oils from your skin, leaving behind food for bacteria. The towel is then hung up damp, creating an environment where mold/mildew can start to grow.", "If hung to dry somewhere with good circulation you can get multiple uses, otherwise the trapped moisture turns mildew-y", "Dead skin cells that are sloughed off. To prevent moldy smells, I only buy white towels and sheets. Wash them with laundry detergent and a small amount of bleach and they always have a clean fresh smell."], "text_urls": [[], [], []], "score": [18, 5, 4]}}, {"q_id": "6w9rk5", "category": "Repost", "title": "When hunting, what's the point of wearing camouflage if you're just gonna wear a bunch of bright orange stuff along with it?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dm6dhli", "dm6dngs", "dm6dmw3", "dm6gf2n", "dm6ndq1", "dm6jwyn", "dm6l4fd", "dm6k84k", "dm6luzs", "dm6oy3n", "dm6mffa", "dm6n7ha", "dm6s3b4", "dm6kjow", "dm6m3r5", "dm6l4zs", "dm6soln", "dm6m73q", "dm6oxaz", "dm6nc3k", "dm6sdq3", "dm6qopo", "dm6o4rc"], "text": ["Deer can't see color, people can...its supposed to keep you from getting shot by another hunter", "* game can't see that shade of orange, but people can * game can see shapes, which camouflage helps obscure", "The point is to break up the human shape with different shadows (or what looks like shadows) and such in various shapes like what is natural in the background environment you are hunting in. Most animals that we hunt are color blind and cannot see the color orange so that is not an issue, but the human shape is an issue. So you want to look like the forest background, or grassland background, etc to blend in and break up your human shape.", "In Wisconsin, blaze orange (and now pink) is worn during deer season as well as upland bird hunting(pheasant and grouse). This is done for visibility. That said, it often helps to have patterns in the blaze orange (camo patterns or black stripes) to break up a silhouette. Some states require a minimum Sq ft of unbroken blaze. Waterfowl and turkey hunting typically does not require blaze. Most birds have incredibly good eyesight and can see some colors so it is essential to blend into your surroundings to the point where your camo patterns should match your natural patterns (spring and fall forests, snow, reed canary grass). TLDR: the camo patterns with blaze orange helps break up a silhouette so while the game may not see orange, they don't see a solid grey blob.", "For upland game birds (e.g. Pheasants, dove, quail) wearing orange prevents you from getting shot since to hunt them you commonly see people hunting in groups and the birds they have to be flushed from usually tall grass and bushes, so camo is not really a necessity. However, since a lot of camo gear can have water resistance and are good in cold weather you will commonly still see hunters wearing it since its practical for morning cold weather....and probably where you will likely see hunters wearing camo that absolutely doesn't match the environment because it's not a big deal. For waterfowl (geese and ducks), you are going to be stationary so the risk of getting shot is minimal, and iirc if you aren't in full camo without orange the birds will not fly in. Orange not really a necessity, but typically a camo pattern resembling reeds is. Turkeys can see color. They are one of the smartest things you can hunt, but then if you're everyone's favorite dinner you evolve to be smart af. Wearing camo and likely sitting in a pop up blind is likely going to be the only chance you have at drawing them in close enough. You cannot wear orange because the bird will know what's up. Makes a risky hunt if other hunters don't know where you are. For larger game like deer, yes most can't see color but they really can differentiate between the black and white and gray shading they see on the world, so camo that matches the geography around you is needed- woodland pattern in woodlands, sage for high desert, etc. typically one can also have orange intermingling in the design of some of the camo, but you'd also hope if someone is targeting a deer they've got a scope and are looking at their target, knowing not to shoot you if you are not wearing orange. TL;DR- geography and the animal being hunted determine necessity of orange, or a particular pattern of camouflage.", "It can be any color as long as it's not solid. I hear it's because color blind animals see pattern disruption more easily. My history teacher told us colorblind soldiers could spot hidden enemy snipers in ww2 more easily if the sniper had a solid color uniform on which is why they were usually put in a scouting role but I'm not sure if that's true. I know turkeys can see color and wearing certain colors can make them fear or want to assault you. Reds and blues I think.", "Dad and I wore jeans, flannels, and bright orange vests forever. Never stopped us from filling our tags. I think a lot of what I see is just men trying to play commando.", "Follow-up: When hunting sure, but what's the point of wearing camouflage if you're just gonna wear a bunch of bright stuff along with it *in the military*? URL_2 URL_1 URL_0", "Seems to be that it's because of outdated information. Most recent articles I could find (a few years old and from newspapers) indicated that deer are RG colorblind. So they can see orange, it just looks like a shade of red.", "the very unpopular truth is that its pointless. people LOVE their camo and feeling like they are doing every little ritualistic preparation to enhance their chances of success. the reality is that people have been successfully hunting for thousands of years before expensive camo patterns were invented. deer are not people, they are not looking for the silhouette of a person, hell they likely dont even know what a person is. They do, however, understand movement, sound and scent, any of which can put the animals on edge.", "Turkey : great eyes. No orange required when hugging. Deer: No orange needed for bow hunting, and you probably gun hunt in a blind unless your driving or something. Duck/ waterfowl : no Orange required. Upland bird: orange needed to not get shot in the face. At least in michigan. By its so thick the birds can't tell.", "Like others have said, many animals can't actually see colour. This is where the \"5 S & M\" of stealth come in: * Shape * Silhouette * Shadow * Smell * Sound * Movement If you can stop any of these appearing human then it increases your chance of not being detected by said animals.", "There's two kinds of hunting: big game and quarry. Big game are often things like deer and elk. Quarry are smaller things such as rodents and birds. Both kinds have very different quality of vision. Big game tends to have terrible vision - so bad in fact that entire parts of the spectrum are missing. They rely instead on sound and smell. Quarry on the other hand has VERY good eyesight and will see you coming unless you try to blend in visually with your surroundings. For this reason you want to wear things like [RealTree]( URL_0 ), as quarry has a hard time determining your size, position, shape and even existence when you're fully dressed in this. When you're hunting one of the most dangerous risks is being shot by another hunter. For this reason hunters wear blaze orange, a colour that deer and elk are blind to. Nobody wants to be completely dressed in orange though, so for the rest of a hunter's outfit they'll try to blend in. That means it's OK to wear camo and orange, but bright blue would be a problem. For this reason you see hunters in camo putting on blaze orange vests. Being shot by other hunters is such a big problem that here in NZ we have rules such as \"completely identify your target - do not rely on sight, sound or movement alone.\" There have been many cases of hunters carrying deer they have killed out on their backs only to be shot because someone thought it was still alive. A common thing to do is to wrap the antlers or dress the deer in an orange vest. Hunters feel slightly better about blending in with the surroundings when it comes to quarry because the calibres are smaller or they use birdshot. It's much easier for another hunter to tell a disguised human from a bird as well. In fact, when you're hunting quarry the most dangerous aspect is still other hunters, but the risk is generally from other hunters not checking their field of fire. What may be beyond their target, or the risk of ricochets from hard surfaces and water, etc. When hunting ducks for example there will be many hunters positioned around a lake - for this reason it's illegal to shoot at birds on the water as you may ricochet or shoot another hunter across the lake directly. When discharging a shotgun at quarry you must be pointing at a bird in flight.", "You wear orange when deer hunting because they are color blind, but you have to wear camo when hunting turkey because they can see colors and can see you.", "Camouflage is needed to obscure the edges of your outline so that the animals can't make out a figure. The orange portions don't compromise that.", "Camo breaks up the human sillouette even if they seen colour the exact same way we do, they would see a bright colour and think for a second or two if they want to run or not. They dont see things like we do, and thus the reflective vest isnt a big factor. Tldr: camo breaks up the human silloutte which is why it works.", "Hunter here. I think non-hunters fail to recognize how much of a fashion show hunting is to some guys. If you go hunting but don't look the part, your Facebook selfies will be terrible. Not everyone hunts because they love the outdoors and prefer organic, humanely-raised meat; for many it's about selfies, shopping for gear, and playing dress up. For my part, I wear camouflage for duck hunting because I don't hunt from a full blind. For deer and upland birds, I just wear whatever is weather appropriate and an orange vest or jacket over it. Then again, I don't have a Facebook page and don't take selfies.", "Theres many good answers here so far. Another point that I didn't see mentioned is that many people will wear blaze orange to walk to their stand, and again later to walk out. But when they are in the tree or in a blind, they take it off.", "Many have answered it, but here is a real life example called \"Dazzle Camo\" Look at this ship: URL_0 See how its outline is obscured and it's awkward. If it were one flat color it'd be easy to gauge what it is. So the camo outline help break up the shape of the person.", "Some animals see the orange, so for them you wear just the camo, mostly bird I believe. Other animals cannot. The method of hunting also dictates the need for additional bright colors. If there are deer hunters in the area you definitely want to be visible, because they may be shooting a long range weapon at an animal and not see you in the brush behind it. I believe this may also be why rifle season is outside of the season of other small game, but that is just a guess. As for someone who only hunts in bright orange, its just not really made, partially because it looks silly, partially because you can buy a 200$ pair of insulated coveralls and a 10$ hat/vest and get an outfit for both situations instead of buying two sets of coveralls.", "I wear it because it's equipment clothing, has extra pockets and I don't care if it gets dirty. You could wear a nice pair of jeans and shoes, but why risk ruining nice clothes?", "there is no point to camouflage in 90% of hunting. in most cases the animal can't differentiate between the colors, or you're up in a tree where they won't look anyway. deer walk right past the brightest colored objects you've ever seen(like road cones with hazard lights blinking on top of them), and they don't care. simply holding still is an order of magnitude more effective than the best camouflage ever made. if you're holding still they won't notice you. they can see you but to a deer you're just another non-living object that's no threat. you could be cosplaying as an overwatch character with blinking LEDs and they wouldn't care as long as you held still enough. the reason people buy it is the same reason they by a special set of clothes for whatever else they're doing. hiking, running, whatever other hobby all have costumes associated with them. camo is the costume for hunting. but that's all it is.", "Bow hunting is often done within very close distances to the prey. Say, stalking a deer and trying to come within 40 meters of it. You need all the stealth in the world on your side for this. You need to be in full head to toe camo for this. For hunting with a rifle however, you can engage as far aways as you can accurately shoot. Maybe out to several hundred meters. You may see what you think is a deer in the binocs, put them down, pick up your rifle and place the reticle on whichever moving target you find first. If a hunter in the distance is wearing full camo, they may inadvertently become a target in this scenario. The other hunter may have been stalking the deer from the other direction. Especially if the wind ended up in his favor. Had they worn orange, even just a vest, or orange gloves, or a hat, it would have been more obvious. Accidents happen occasionally when a hunter is on his private property, and is shot by another hunter either aiming into property which is not his, or is straight up hunting illegally on someone elses land. Tl:dr Using camo is sometimes entirely necessary (walk and stalk with a bow), and other times entirely unneccessary (rifle hunting, at longer distances). PS, Something else important to note, bullets are cheap, and arrows are expensive. Rifle/shotgun Hunters have been known to get trigger happy and the more bullets put down range, the better chance that one hits something it shouldnt. And from the shooters perspective, more bullets down range equals a high chance of hitting the intended target. PPS, ALWAYS KNOW WHAT LIES BEYOND YOUR TARGET, AND NEVER TAKE A SHOT IF YOU CANNOT GAURANTEE YOU WILL HIT WHAT YOU ARE AIMING AT (beyond a reasonable doubt, at least, no one is 100% accurate)."], "text_urls": [[], [], [], [], [], [], [], ["http://i.dailymail.co.uk/i/pix/2014/03/26/article-2589722-1C8E3A0500000578-6_634x506.jpg", "http://i.dailymail.co.uk/i/pix/2014/03/26/article-2589722-1C95CCDE00000578-820_306x423.jpg", "http://starecat.com/content/wp-content/uploads/do-you-want-to-be-seen-or-not-mate-camouflage-safety-vest.jpg"], [], [], [], [], ["https://www.realtree.com/sites/default/files/styles/scaled_and_cropped_site_preview/public/content/camo/swatchxtra.jpg?itok=AVTGtJzb"], [], [], [], [], [], ["https://en.wikipedia.org/wiki/Dazzle_camouflage#/media/File:HMS_President_Dazzle_2.jpg"], [], [], [], []], "score": [5897, 3425, 643, 498, 244, 91, 56, 26, 16, 15, 11, 9, 9, 8, 7, 5, 5, 4, 4, 4, 3, 3, 3]}}, {"q_id": "6wb0oc", "category": "Repost", "title": "why do American trucks (an extended nose containing an engine) and European lorries (flat face engine under the driver) look different?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dm6p1f7", "dm6omzw"], "text": ["Most countries in the world have regulations defining the size of vehicles that are allowed to use their roads. This is necessary so that they can plan junctions, bridges, and so on. In the EU and other European countries, the law defines the maximum length of a truck to include both trailer and cab. In North America the law only defines the length of the trailer. Long-nosed cabs are generally cheaper to build and easier to maintain, so in North America where the length of the cab doesn't matter this is the most common design. In Europe, where every additional metre on the cab's length means a metre less available for the trailer (and hence fewer goods transported and therefore less money being made) the snub-nosed cab is the one that's usually used.", "This is not just a US vs EU thing, there are flat nosed trucks in the US/Canada too. A flat-faced truck is called a \"cab over\". A big advantage of cab over designs is it decreases the overall length of the vehicle, which reflects places and/or times when there were laws regarding length of the vehicle. more at URL_0"], "text_urls": [[], ["https://en.wikipedia.org/wiki/Cab_over"]], "score": [5, 3]}}, {"q_id": "6wbi5v", "category": "Repost", "title": "Why do most men go bald, in spite of all the testosterone?", "title_urls": {"url": []}, "selftext": "I'm 25, I have a full beard, I have new hair coming out on my back and shoulders but the hair on top of my head have started falling. What's up with that? Are the rules different for that part of the body? EDIT: What the hell? Ads about hair products started showing on reddit. Ads do get smarter.", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dm6vkqa", "dm7fmn6", "dm6xp1p", "dm74upe", "dm700p5", "dm6vkqv", "dm7tbet", "dm7141m", "dm6wobg", "dm747ja", "dm6s0qm", "dm6z6lh", "dm787qk", "dm6v897", "dm735yd", "dm77dc8", "dm6x1m8", "dm78suj", "dm70ygp", "dm71jha", "dm6s47j", "dm6zuyt", "dm7c2ze", "dm7923f"], "text": ["Testosterone gets converted in the body to something called DHT (dihydrotestosterone) which is useful for many important things in the body. People have different types of hair folicles and The ones on our head are actually different to the ones on our body, they have a much longer growth cycle and are sensitive to DHT. DHT binds to the hair follicles on the head which makes them weaker and with every growth cycle, the hair will grow thinner and thinner until it can no longer penetrate through the skin anymore. Hair loss medications use a form of DHT blocker (finasteride, Azelaic acid, etc) combined with other stuff to free the weakened hair follicles from DHT and allow them to regain some or all of their strength. body builders, athletes and other steroid users who inject testosterone also end up increasing their DHT levels because there is more test to convert. This is why hair loss is a common side effect of anabolic steroids.", "It's because of a genetic mutation that causes a specific area of the scalps follicles to be sensitive to DHT - a preprogrammed pattern. It takes a long time for the follicles to respond to the onset of it but eventually it gets ya. I am bald on top and it actually initially started with me when I was 17 at the very edges of my forehead! So minor it was back then, but 18 rolled by and it wasn't too bad, then 19 it got slightly worse, creating the more defined M shape (no spam at the back first, thankfully), then 20 it progressed quite a lot on the tops of the left and right of the forehead and by 21 it got so bad at the left and right of my forehead that I started shaving my head completely. Realistically I could have just had short hair but meh. Through 21 to 28 it thinned out on top completely so I now have the definitive horseshoe shape if I don't cut my hair, but I shave my head completely anyway. If I run my hand across my head through the middle there is still a quite a few bristles but no where near enough to grow it - I am fortunate my hair is a mousy blonde colour so it doesn't show as much. Fortunately I don't look too bad bald/shaved and kind of suit it. Some people are very unfortunate and do not. So yeah, testosterone encourages hair growth, but a messed up genetic mutation is why a predetermined pattern of weakened hair, sensitive to DHT is why we lose it. Like all of these things, just like other genetic inheritance of, say, diseases, the onset is unknown but expresses itself within a certain time frame - this is why some of us get hair loss at varying times, some very late, some super early (like me). For example; my Dad is bald and his Mother, who he heavily takes after, her father was bald. I take heavily after my Dad but he had decent hair till his mid 20s, I didn't. It was a lot more pronounced on my forehead earlier on than on my Father. My Grandfather, who I don't take after much, is bald but that didn't affect him till his 50s. So the genes are all there. My Brother however takes heavily after my Mother, whose father isn't bald nor is my Mother's father (as far as I am aware). So while my Brother is whining about his receding hairline at the corners, left and right of his forehead, and has been moaning about it for years, his hair receding is so minor it seems to me, ridiculous. My brother is 9 months younger than me and he has almost all of his hair. He is at the stage I was at 19/20! (We are currently both 28, but I will be 29 in February). Blah, rambles. My apologies. A lot of shit will happen if you cherish your locks... Or not. Look at your family history and try not to worry too much. There are ways of slowing hair loss, even if it is genetic Male Pattern Baldness (MPB). However do not go spending fortunes on trying to cure the inevitable. There are cost effective solutions that can slow the process but it isn't a guarantee for everyone. Or, you may be lucky and it may not progress heavily till you are older. You may experience a roller-coaster of emotions or you may be more chilled about hair loss like I was. There will be moments in your life where you get pangs and thoughts or wishes of having hair or doing something about (transplants, research, etc) but the best way to be is to be accepting of yourself and not trying to please everyone else. My brother once told me that the new people you meet will not find you ugly or weird looking because they have only ever seen you with your head shaved... So yeah that helped me when I had my doubts about going out. If you are worried and it appears to be progressive, instead of clinging on to hair like it is all there is to life, experiment with shorter hair styles gradually over the years until eventually cutting it to 0.5mm with a trimmer - this means it is a less drastic or shocking change to people you are around rather than going from longish hair to slap head, because stark differences, whether it be hair or anything else is always going to draw attention. You don't have to go cue-ball style. In fact, I never even started using a razor on my head until a couple of months ago! You really don't need to use a razor. Short and tidy 0.5mm hair will show a faint outline of where your hairline is, but because it's very short it looks good, not old man style. Embrace le bald when the time comes, it is not as bad as you think. All the best dude. Remember, don't worry! (\u0e07\u30c4)\u0e27 (Edit: added info, corrected mistakes - forgive me, I was having a hypo :D)", "I was reading an article about fecal transplants the other day and found an interesting anecdote- apparently sometimes bald men who have fecal transplants start growing hair again. It may turn out that it's much more complicated than we think. Found the article- URL_0", "Men go bald *because of*, not in spite of, testosterone. DHT is a similar hormone to testosterone.* How much free-circulating testosterone, and how much free-circulating DHT you have in your blood determine a lot of things. Male hormones are often spoken of in terms of how anabolic and androgenic they are. Anabolic basically means binding to receptors in muscles and making 'em grow. Androgenic basically means binding to receptors in other tissues and making 'em do other man stuff. DHT is somewhat anabolic, and much more androgenic than testosterone. When it binds to hairs, it makes them convert from baby-soft, lighter, finer hair type, to old-man, darker, thicker type. DHT is also mostly responsible for the progress of male pattern baldness, thickening and darkening of facial hair, chest hair, and pubes. Here's a source talking about how male pattern baldness may be related to some sort of disorder with DHT: URL_0 EDIT: DHT is *not* \"basically 2 testosterones hooked together\".", "My understanding is that hair all over the body has different responses to testosterone (especially when it gets converted to DHT that causes hair follicles to fall out). Beard hair tends to grow more with more testosterone but hair on the crown (front hairline to the the \u201cbald spot\u201d area on the back of he head) tends to fall out due to DHT. Facial hair and hair around the side and back of the head is more resistant to DHT and therefore doesn\u2019t usually fall out (leading to the old man hair we usually think of, i.e. bald on top and front but hair on the side and back of head). This is why hair transplants tend to pull hair roots from the back of the head since they are more resistant to DHT. I started seeing my hairline recede when I was 24 and I started using minoxidil (Rogaine) and it helped me keep most of my hair. The sooner you start treatment the better the results, but you have to keep using for the rest of your life or it will start to fall out. Minoxidil and propecia (proscar) are the only FDA approved drugs to treat hair loss. Everything else out there has yet to be medically proven to work. Fun fact, hair lost isn\u2019t actually \u201cdead\u201d but is just in a really long resting phase. Your hair is constantly going from growing, falling out, resting then growing phases. Eventually your hair just rest permanently then you have balding in that area.", "Male pattern baldness is related to a sex-linked recessive gene, and not really tied to the rest of your body since that's other genes. What does that mean? When your parents love it up and make you, two sex chromosome are passed on. Women always pass an x (because they're xx) and men can pass an x or y (because they're xy). The gene that tells your body \"Hey, don't go bald please\" sits on the x chromosome. If you're male, you only get one x chromosome so you only get one chance that you have this gene buddy looking out for you (that's the sex-linked part). If you're female, you have two chances so if one x is saying \"Hey, go bald\" and the other is saying \"Nah, we ain't doing that\", the latter takes over (that's the recessive part, since it takes a lack of \"don't go bald\" instead of a presence of \"go bald\" to happen). So, if you're ever worried if it's going to happen to you, it always helps to look at your mother's family history.", "- 95% of balding is due to Androgenic Alopecia, a hereditary gene. You can get them from either your Mother or Father, not just the maternal side as one myth is reported. The other 5% is often due to underlying health issues like Thyroid problems, Stress induced hairloss (Telogen Effluvium) or other conditions called Alopecia Areata, Alopecia Totalis. - Classic MPB (Male Pattern Baldness) comes normally in two forms. One is the \u2018\u2019classic\u2019\u2019 type where you see a recession of the hairline at the temples into a deep \u2018M\u2019 shape followed by a bald spot at the crown (around where your cowlick can be). The bald spot often gets bigger and bigger until it joins at the hairline. These are examples of more extreme baldness where the spot meets the hairline and is normally classified under the Norwood hairloss scale as types V, VI & VII. The other type of male hairloss due to genetics called diffuse hairloss. There is not often a recession of the hairline at the temples but instead the whole top goes out over time. Reports have said this is generally a more aggressive form of hairloss but the severity of the hairloss is generally more down to the individual and their genetics. - A link to the Norwood hairloss scale: URL_1 - Hairloss in women comes under the Ludwig scale and \u2018\u2019generally\u2019\u2019 follows a different pattern to men where the centre parting of hair gets wider and wider. - A link to the Ludwig hairloss scale for women: URL_0 - Hairloss is down to your genetic sensitivity to your own hormones. Everyone, man and women but men in higher quantities have a hormone in your body called DHT (Dihydro-testosterone). It is a far more potent form of Testosterone and gives men their male characteristics such as deep voice, body hair and formation of male genitalia. It is produced in the Prostate, Testicles, Adrenal Glands & Hair Follicles. - People say that it is high levels of DHT that cause baldness or high levels of Testosterone but this is incorrect. It\u2019s actually how sensitive you are to your own hormones and how many receptor you have in your existing hair follicles. You could have incredibly low DHT levels but a lot of receptor sites in your hair follicles thus becoming bald or incredibly high DHT levels but if you have very little DHT receptors in your hair follicles then you likely won\u2019t go very bald or at all. Also a myth exists that men who go bald have more testosterone, this is also not true. It's all down to the individual. - People believe there are other causations and reasons for balding but the DHT theory in combination with chronic but low level inflammation in the scalp (which is why your scalp can itch) is generally the most widely accepted. There is other things regarding KROX-20, WNT pathways, PGD2 and Lactate production but I won\u2019t get into them. They are still being debated and until we have more evidence people generally just tackle DHT as the primary culprit. - At the moment the only two FDA approved treatments for hairloss is Minoxidil (Rogaine, Regaine, Kirkland etc) and Propecia/Finasteride. However, both are life long commitments and can come with side effects. Minoxidil is a vasodilator meaning it increases blood supply to the area it is applied. Some people manage to maintain, a lucky few grow some hair back and an unlucky few actually lose hair. Other reported side effects are dark circles under the eyes, shortness of breath, heart palpitations and even aging of skin due to it (allegedly) inhibiting collagen production in the skin. - Propecia/Finasteride first patented by Merck for BPH (Enlarged Prostate) until they discovered it could stop or slow down balding and now produced also elsewhere by other companies is an oral medication that stops the conversion of Testosterone into DHT by blocking the mechanism 5-AR. Some people report good results and maintain or even regrow some hair however in recent years a lot of reports side effects (primarily of a sexual manner) but also of a psychological manner have surfaced. Merck claimed 1-2% of men got these side effects but other studies say it is far, far higher. These side effects can include testicle ache, weak or useless erections, watery semen, loss of libido and depression. Merck claims all side effects should stop once the drug is stopped but some individuals report side effects lasting months or years after cessation. There is a longer list but I will not get into them. I had side effects for 16 months. I was on it for 3 weeks. - Finasteride/Propecia is often prescribed by a Doctor. It generally comes in a 1mg pill which is to be taken daily but some people take 0.25mg every day or up to 1.25mg every day by splitting the 5mg pills into quarters. 5mg is generally used for enlarged prostate. Propecia/Finasteride stops the conversion of Testosterone to DHT by up to 70%. Whilst people are still not completely 100% the reason a lot of men (but some don\u2019t) get side effects is because they are decreasing their primary male hormone by a large quantity. This medication should not be used by women and ideally not men who have not finished developing (18-21). - There are other things that can stop or prevent hairloss but they are likely not very effective. There is a lot of fake and phony products on the market that exist purely to take money from them. Please please do your research before purchasing hairloss products. Forums are easy to find and so is the information. - There is also HT (Hair Transplants) but they can be expensive, ineffective or give a very un-natural look plus there is alot of dodgy HT doctors out there so DO YOUR RESEARCH should you choose to go down this route. Also alot of Doctors recommend you take Propecia/Finasteride after a HT but if you had side effects or don't want to take medication the rest of your life HT can be only a temporary fix before you lose more hair. - Upcoming treatments: Science is advancing at an incredible rate but a lot of people complain that we are yet to have a safe cure for balding. I will not go into great detail but there is currently many companies who are working on alternate treatments. There is big $$$ to be made. If you are reading this and are particularly depressed about going bald here are some companies or upcoming drugs you could look into; - Replicel/Sheseido - Tsuji Hair Cloning - Brotzu Hair Lotion (FIDIA) - JAK Inhibitors - Follica - Follicum - Rivertown Therapeutics - Allergan (Setipiprant) -Fevipiprant (for asthma but some evidence theorises it could be very effective for balding) - Why does curing hairloss even matter? A lot of people say we should be curing things like Cancer, HIV, MS, Dementia and Diabetes instead of hairloss but currently we are trying to cure all that are listed and hairloss. Just like women deserve a safer alternative to the pill (messing with hormones is not safe alot of the time, the balance is very delicate) men and women also deserve safer alternatives to hairloss. - Some people go bald and it\u2019s not a big deal, they own it and look great and honestly I say absolute power to you. However, many young men and women (typically who go bald faster as it begins earlier) find balding very destructive to their self-esteem and confidence. We live in a world now where vanity is becoming more and more prominent. Not only that but losing hair, particularly at a young age can destroy ones confidence. Especially when you are in the process of discovering who you are. On top of that there is also a stigma against men wearing wigs but not against women and if men are discovered they will often be ridiculed or called \u2018\u2019shallow\u2019\u2019 or \u2018\u2019vain\u2019\u2019. - I hope this post has cleared up some information. If anyone notices corrections please feel free to comment and I\u2019ll adjust the post accordingly. I tried not to be biased too much but as a young individual losing their hair fast and young it\u2019s a hard burden to carry, particularly when conventional treatments did me more damage than good. Oh and inb4; - \u2018\u2019Just shave it and hit the gym\u2019\u2019 \u2013 Some of don\u2019t want to be ripped. - \"Some girls/guys love bald guys\u2019\u2019 \u2013 Great but some of us don\u2019t love being bald guys. - Any comments regarding Jason Statham, Vin Diesel, The Rock or Patrick Stewart. These men are the exception but we are bored of seeing their names in every hairloss thread. Myself and many others don't aspire to be this men. We merely aspire to be comfortable in our skin. - \"Get over it, it\u2019s only hair\u2019\u2019. Ok, let me remove your favourite feature of your body and then get over it.", "I'm the only guy in my family who is not bald. I'm in my 40s. At Thanksgiving at the dinner table it is like sitting in an egg carton. Something must be hereditary but it is not a sure thing. Edit: people keep joking that I was adopted or it was the mailman. My mom says I wasn't and we got the mail from a community mailbox. Here is a picture of me with me two sisters and brother. I am wearing the overalls and have the red stripe on the soles of my shoes. [Pic]( URL_0 )", "Do men who transition to female after having already gone bald regrow their hair? Do they at least stop losing more hair once they start female hormone treatments?", "Thickness and amount of hair is not something you can look at to determine how much testosterone you have. Everyone has peach fuzz hairs and each follicle has a testosterone threshold that, when exceeded, signals the follicle to pigment the hair and grow longer/thicker. This threshold is a result of your genes. A man with a full beard could well have less testosterone than a man who can't grow a beard at all. Generally speaking, those with crazy thick/long hair just have a lower testosterone threshold to stimulate growth in the follicles. Edit: This doesn't quite answer your question, but I believe this information to be pertinent.", "If I remember correctly, a running pattern amongst prematurely balding men is high testosterone levels.", "DHT (dihydrotestosterone) is a downstream product of testosterone. DHT It is found in lower concentrations but is more portent than T. The hair follicles on the top of your head are more sensitive to DHT. Some people's are extra sensitive depending on their genes and they end up with complete hair loss in that area. The reason hair transplants work and don't immediate fall out is due to the choice of hair to transplant with. Public hair from your back is sensitive to DHT but in the opposite way. Its growth is promoted. Your hair loss is normal and is part of the normal growth process. Don't fight it with any DHT blockers and enjoy the added benefits at the gym and in the bed from the extra DHT you seem to be making now.", "It's not \"most men\". There's a large genetic factor which plays out in multiple ways (i.e. levels of testosterone). However, it's a double edged sword. For example, I'm in my 30s and I've never grown a full beard, even after a month of not shaving.", "Nobody knows why, but hair along the top of male heads reacts opposite-ly to the presence of DHT, a product of testosterone. Where body and beard hair grow stronger, in that one zone, dht causes inflammation m and the hair stops growing. Why that spot? Nobody knows. Why only men and not women ( even those who take testosterone )? Nobody knows. Edit: women get forms of baldness too, but not the pattern of no hair on top, hair remaining on sides that OP asked about.", "You say \"in spite of all this testosterone\" as if you never heard of the term male pattern baldness. Your testosterone is turning to DHT and making you go bald. It is the testosterones fault.", "Testosterone is converted to DHT. DHT acts locally on hair follicles. DHT *stabilizes* follicles of chest/beard hair, whereas DHT promotes the *degradation* of hair follicles on your head. So it's not \"in spite of,\" it's \"because of\"", "Testosterone and its associated hormones can have drastically different effects on different types of hair follicles. Beard growth and body hair can be stimulated by extra testosterone, whereas DHT, a hormone made from testosterone by the body, is linked to the shutting down of hair follicles that results in male pattern baldness.", "Genetics. Alopecia specifically is a trait that is carried primarily by men and leads to baldness.", "Testosterone promotes the growth of body and facial, but it is actually the cause of male pattern baldness. Receding hair line, and such.", "It's actually **because** of all the testosterone. Your body can start to metabolize testosterone as Dihydrotestosterone, which causes male patter baldness (loss of hair on your head).", "Baldness is actually associated with testosterone; it's actually theorized that it's an evolutionary sign of seniority (like a gorilla's silver back) that is viewed in an entirely different light socially.", "DHT causes the baldness, bro. It's in fact too much testosterone that causes male pattern baldness. Basically the reason you can grow a thick beard is the same reason you're going bald.", "So scientists don't know exactly why male pattern baldness happens but, found it's cause to be from DHT (a chemical byproduct) from testosterone settling around the scalp. DHT strains the follicle productivity, causing hair to thin and eventually to stop producing. There are some remedies that can help however. Like drinking certain teas, essential oil application, and other ways. For another example there are also little tools like micro needle rollers that help too.", "I don't know what the statistics are, but in my time working in nursing homes so far I've seen a lot of very old men who still had a full head of hair, though often it was thinner than when they were young. Pretty sure it's just genetic. I see a lot of bald heads too, mind you, but it's not so rare to see men in their 80's and 90's who still have their hair."], "text_urls": [[], [], ["https://www.wired.com/2016/11/microbiome-therapy-making-fecal-transplants-better/"], ["http://www.medicalnewstoday.com/articles/68082.php"], [], [], ["http://haircanada.net/wp-content/uploads/2016/04/womens-hairloss-scale-birmingham.jpg", "http://www.vivanditrichology.com/images/understand-men.jpg"], ["http://1.bp.blogspot.com/-mDe8FKHAf6k/UuCV_F3XKgI/AAAAAAAAJLk/zjYnIdgBCws/s1600/DSC_5757.jpg"], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], []], "score": [2151, 518, 202, 150, 140, 115, 61, 47, 30, 27, 17, 15, 11, 11, 7, 7, 7, 3, 3, 3, 3, 3, 3, 3]}}, {"q_id": "6wcbsr", "category": "Repost", "title": "What is the chalk at the billiards table for?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dm6xcou"], "text": ["You rub it on the end of the cues to make the contact surface less slippery, so that more of the force of a stroke is transmitted to the cueball. Same reason gymnasts rub their hands in it when swinging on beams, to maintain grip."], "text_urls": [[]], "score": [4]}}, {"q_id": "6wdmq6", "category": "Repost", "title": "Why does extreme physical exertion sometimes cause vomiting? What is the body trying to rid itself of?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dm77q3k", "dm7nvtg", "dm7ats3"], "text": ["i believe it has something to do with the fact that physical exertion diverts blood away from the digestive system and to the muscles, so it could be your digestive system trying to get rid of the food so it doesn't have to digest anything while you are exercising edit: spelling", "While exercising, your muscles release lactic acid which in turn breaks down into Hydrogen ions, water, and CO2. The hydrogen is acidic and thus increases your bodies acidity level( pH).Hydrogen takes a long time to be removed or broken down by the body and so the only fast way to lower the pH levels in your body is to throw up the stomach acid ( hydrochloric acid) which contains hydrogen. This brings the body back down to an equilibrium where the organs cells ect can work in an optimal environment that is not too acidic.", "When you run, especially if you're running because of panic, the body diverts blood from the digestive system and into the heart and lungs. The body then gives the command to vomit because that undigested food is weighing you down as you try to escape, and there is the chance that the predator might stop to eat the contents."], "text_urls": [[], [], []], "score": [9, 5, 3]}}, {"q_id": "6wdtza", "category": "Repost", "title": "How does wind works? Where does it come from?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dm7bsz9", "dm79hxz"], "text": ["The sun heats up the land, also heating the air above it. Hot air rises (see:hot air balloons) when there is cooler air around it because it is less dense. The space left by the rising hot air is filled by cold air from the areas near it, and the movement to replace the hot air is wind. ELI10, the difference in absorbed solar radiation, the constant day night cycle, and the rotation of the earth create different, reliable wind patterns like the jet stream and trade winds. The cold air from the poles moves on the surface towards the equator, where it warms and rises and returns north, creating huge convection cells. There are also smaller ones in bands between the tropics. Everything circulates like water in a boiling pot, but with several systems operating simultaneously. The exact same principles apply to ocean currents. Tldr pockets of varying pressure due to temperature difference constantly try to equalize by mixing.", "The sun heats the earth unevenly. Warm air and colder air move around because they are different temperatures. [Here are some threads from this sub on the ."], "text_urls": [[], []], "score": [6, 4]}}, {"q_id": "6wecy7", "category": "Repost", "title": "How can something be see through on one side but reflective on the other like a 2 way mirror", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dm7da3e"], "text": ["The glass is coated with, or has encased within, a thin and almost-transparent layer of metal (usually aluminum). The result is a mirrored surface that reflects some light and is penetrated by the rest. Light always passes equally in both directions. However, when one side is brightly lit and the other kept dark, the darker side becomes difficult to see from the brightly lit side because it is masked by the much brighter reflection of the lit side. If you want to know how this works on a technical level, the r/askscience folks might be able to explain it. Here's the not very helpful wikipedia page on the subject: URL_0"], "text_urls": [["https://en.wikipedia.org/wiki/Reciprocity_(electromagnetism)"]], "score": [3]}}, {"q_id": "6wf3ew", "category": "Repost", "title": "How are older films re-released in 4k resolution?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dm7j44t"], "text": ["Films on actual photographic film have extremely high resolution, limited only by the grain and state of preservation. To re-release in 4K, they scan it with a better scanner than they used for previous video releases, usually do some color correction, and release it."], "text_urls": [[]], "score": [3]}}, {"q_id": "6wg7ds", "category": "Repost", "title": "Where did the \"recommended by 4 out of 5 dentists\" thing come from?", "title_urls": {"url": []}, "selftext": "I mean I have never heard the 4 out of 5 thing been used outside of dentistry field. Where did this come from and why is it only used with dental hygienic products?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dm7tfdf"], "text": ["The bullshit survey of experts is a marketing tactic that seems to have started in the 50s. Trident Gum's dentist survey (from the 70s) is certainly the most remembered (actual results: 4 our of 5 dentists agreed that sugar-free gum was *preferable to sugar gum*, 5th dentist said \"don't chew gum period\"). Other examples include [Whiska's cat food]( URL_3 ), [Camel Cigarettes]( URL_0 ), and, uh, [Chun King Chow Mein]( URL_1 ). It's easy to get a survey to say what you want - I understand that the Camel survey was included with a case of free cigarettes. And of course, you can just keep taking surveys or rephrasing questions until you get an impressive statistic. And apparently, [nine out of ten doctors would not recommend being a doctor.]( URL_2 )"], "text_urls": [["https://www.youtube.com/watch?v=cKMn-_aQoPk", "http://www.targetmarketingmag.com/article/the-zaniest-mad-men-stan-freberg/", "http://america.aljazeera.com/watch/shows/america-tonight/articles/2014/7/9/here-s-why-9-outof10doctorswouldntrecommendmedicineasaprofession.html", "https://en.wikipedia.org/wiki/Whiskas#Marketing"]], "score": [4]}}, {"q_id": "6whkb3", "category": "Repost", "title": "If I touch a puddle that has an electrical cable in it, I'll get shocked. If I throw an electrical cable into the sea, why will not everything in the entire ocean become shocked?", "title_urls": {"url": []}, "selftext": "Does electricity 'dilute' itself in water? If I was close to the source of electricity would I get shocked then? How close would I need to be? Would the direction matter? Is there like a certain equation for how much electricity weakens by taking into account number of electricities and number of waters?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dm83xy2", "dm83yjm"], "text": ["When you are shocked it's from electrons flowing through your body. Electrons on a finite thing. There are only so many of them. The amount of electrons that can be drawn from the outlets in a typical building are way way way more than are needed to kill a human. However the Ocean is really really really big. Whatever powercord your throw into the ocean eventually leads back to a circuit breaker. The amount of electrons that can be drawn into the ocean depends on what that circuit breaker is rated for. Even if it's a huge break, say 600 amps, that's no where near enough to hurt everything in the ocean. Modeling something like this is tricky because there are a lot of things we don't know. To start with pure water doesn't conduct electricity. However dissolved minerals in the water do. The ocean is salt water and does conduct electricity. However the saltiness of the water isn't the same in every drop so some patches of water might conduct electricity better than others. If you compare the end of the electrical cable with the ocean, the cable will have a much higher concentration of electrons so yes, the closer you are to the cable the more likely those electrons will try to go through you and hurt you. So yes the voltage does dissipate with distance.", "Yes, it spreads out, and some of the energy is lost to heat as it travels as current. When lightning strikes water, it will spread out in a hemisphere under the surface, the energy dissipating with the cube of the radius. You would certainly be shocked if you were close to where it struck, because you are not much different from water yourself, and the current would travel through you too."], "text_urls": [[], []], "score": [5, 3]}}, {"q_id": "6wih9o", "category": "Repost", "title": "How do sex scenes in movies/tv work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dm8999m", "dm8aasw", "dm89l2k"], "text": ["Carefully selected angles and skin coloured underwear/thongs. Usually the crew will be reduced to the minimum so that the actors don't feel too exposed in their nudity. Unless you see the actual genital intercourse (as in porn) it's not happening. Just rubbing. Samuel L. Jackson said in an interview he always apologised beforehand to the lady in case he got hard. And also in case he didn't.", "In addition to the above, Lars Von Trier filmed porn actors actually having sex and superimposed the actors heads on it in Nymphomaniac", "It very much varies. Some scenes the director will carefully pick the angle, some will have a touch of CGI, some will use flesh coloured underwear. Others will go up to the actors actually being naked... And a small number... A very small number outside of porn... They will actually be having sex. Intimacy, and The Brown Bunny spring to mind for that last category."], "text_urls": [[], [], []], "score": [17, 3, 3]}}, {"q_id": "6wl9xn", "category": "Repost", "title": "Why is it easier to hit flies with a swatter than with your bare hands?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dm8ueso", "dm8uiw9"], "text": ["Bunches of reasons. For one you can see that they are on a long arm which acts as a lever, turning a greater force over a short distance into a lesser force over a longer distance. This trades power for speed, and as your arm can exert far more power than is required to mash a fly but cannot move fast enough that is a great trade. Another reason is that the swatter is much less massive than your arm and hand which means it is easier to accelerate to fly-mashing speeds. Finally another reason is that the wide swatting head has holes in it which reduce the air resistance while still being closely spaced enough to impact the fly. Your hand is unavoidably solid so air must go all the way around it rather than through it. Flies also have hairs which allow them to feel air movement from oncoming objects such as predators and allowing most of the air to flow through the swatter reduces that warning to the fly. The combination of all those factors is a wide swatting head which can be moved far faster than your arm and hand, catching the flies before they can take off and flee.", "Yo ho ho! Yer not alone in askin', and kind strangers have explained: 1. [ELI5: Why does a fly swatter work better than your hands? ]( URL_0 ) 1. [ELI5:Why does using a fly swatter make me so much more effective at killing flies? ]( URL_5 ) 1. [ELI5: Why is it easy to kill flies with a fly swatter, but hard to kill them with your bare hands? ]( URL_4 ) 1. [ELI5: How come it's near impossible to kill a fly with my hand but so easy to kill it with a flyswatter? ]( URL_2 ) 1. [ELI5: Why is it so much easier to kill a fly with a flyswatter or newspaper than with your hand? ]( URL_1 ) 1. [ELI5: Why do fly swatters work so well? If I try to catch a fly / smack it with my hand I can never get it. ]( URL_7 ) 1. [Why does a fly swatter instakill flies but when I hit flies with my hand it does nothing? ]( URL_3 ) 1. [ELI5: Why is it so hard to kill flies with anything other than a fly swatter? ]( URL_8 ) 1. [Why is it so hard to swat a fly with your hand but easier with newspaper? ]( URL_6 )"], "text_urls": [[], ["https://www.reddit.com/r/explainlikeimfive/comments/30fdho/eli5_why_does_a_fly_swatter_work_better_than_your/", "https://www.reddit.com/r/explainlikeimfive/comments/2bhju1/eli5_why_is_it_so_much_easier_to_kill_a_fly_with/", "https://www.reddit.com/r/explainlikeimfive/comments/3dqjce/eli5_how_come_its_near_impossible_to_kill_a_fly/", "https://www.reddit.com/r/NoStupidQuestions/comments/6h3d3n/why_does_a_fly_swatter_instakill_flies_but_when_i/", "https://www.reddit.com/r/explainlikeimfive/comments/1mqn16/eli5_why_is_it_easy_to_kill_flies_with_a_fly/", "https://www.reddit.com/r/explainlikeimfive/comments/1ls5pn/eli5why_does_using_a_fly_swatter_make_me_so_much/", "https://www.reddit.com/r/explainlikeimfive/comments/1kopfk/why_is_it_so_hard_to_swat_a_fly_with_your_hand/", "https://www.reddit.com/r/explainlikeimfive/comments/3b86wq/eli5_why_do_fly_swatters_work_so_well_if_i_try_to/", "https://www.reddit.com/r/explainlikeimfive/comments/5543kz/eli5_why_is_it_so_hard_to_kill_flies_with/"]], "score": [25, 15]}}, {"q_id": "6wlmy4", "category": "Repost", "title": "The Poincare Conjecture", "title_urls": {"url": []}, "selftext": "This math problem was one of 10 millineum problems that were really difficult to solve, with a million dollar prize. One russian mathematician called Grigori Perelman managed to prove the conjecture which deals with the branch of mathematics concerned with topography. Someone please explain the Poincare Conjecture in layman's terms?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dm8yozb"], "text": ["The Poincare Conjecture states: > Every simply connected, closed 3-manifold is homeomorphic to the 3-sphere. Let's break it down: *Manifold* - Basically this is just a topological shape.There are some general rules for what is and isn't a manifold, but if, when you zoom in, it could be flattened out, it's a manifold. *3-manifold* - This is how many dimensions we're working with. A point is 0-dimensions. A circle is 1. A sphere is 2. We're talking about a manifold with 3 dimensions. *Closed* - There is no boundary. Think of a sphere. You can walk along the surface of a sphere forever, without reaching an \"edge\" or end. Compare with a sheet of paper where you will. *Simply Connected* - Basically, there are no holes in our manifold. A sphere is simply connected. A donut is not. *3-sphere* - A special type of 3-manifold. Analgous to the traditional \"sphere\" (2-sphere) that we think of. A 2-sphere is every point equidistant from a center in 3D space. A 3-sphere is every point equidistant from a center in 4D space. *Homeomorphic* - A fancy way of saying that you can take one, change its shape (without ripping or tearing or breaking it apart) and turn it into a different shape. So, it's saying that you can take any three dimensional manifold that has no boundaries or holes and morph it so that it becomes a 3-sphere."], "text_urls": [[]], "score": [3]}}, {"q_id": "6wmk58", "category": "Repost", "title": "Why do some clocks with roman numerals use IIII for the number 4?", "title_urls": {"url": []}, "selftext": "I have noticed that some clocks with roman numerals have 'IV' and some with 'IIII' for the number 4. why is this the case?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dm953ri", "dm95a9g", "dm96xry"], "text": ["It just the tastes of the clock maker. It's particularly common for clock faces to use IIII for 4, but still use IX for 9. The Romans weren't nearly as rigid about how Roman numerals were to be used as we are today when teaching people about them. IIII vs. IV, XVIII vs. XIIX, VIIII vs. IX... there's even examples of people using two different forms in the same document. It's just how they rolled.", "The explanation I've heard is that IV is written the same as JU in old Latin script, which are the first two letters in Jupiter, the most powerful Roman god (analogous to Zeus). People didn't want that, either because they were superstitious pagans who didn't want to draw Jupiter's attention/wrath, or they were Christians who didn't want to appear that they were invoking the name of a pagan god in their homes.", "The reason isn't completely clear, there are a number of possible explanations: * both the 4 and 6 are upside down, so IV and VI could be confused * IIII balances better with XIII at the opposite location * IIII allows for a round number I's, V's, and X's to be made for each clock * IV was not a universal usage, some Romans used IIII for 4"], "text_urls": [[], [], []], "score": [16, 6, 5]}}, {"q_id": "6wu7av", "category": "Repost", "title": "when in a moving vehicle how can an insect fly around freely without being sucked to the back?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dmasavj"], "text": ["Inside the car, the air is moving at the speed of the car. It feels very different if you roll down a window and stick your arm out. The fly flys in the air, not the car. Since the back window of the car is pushing the air to move it forward, the fly is going from place to place at high speed but not experiencing the air drag (just like you)."], "text_urls": [[]], "score": [10]}}, {"q_id": "6wusyq", "category": "Repost", "title": "How do instincts get passed on from generation to generation?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dmayui9"], "text": ["Yarr! Yer not alone in askin', and kind strangers have explained: 1. [ELI5: How do animals like Ants and Birds instinctually know how to build their dwellings/homes? ]( URL_8 ) 1. [ELI5: How is instinct developed and passed through generations? ]( URL_6 ) 1. [ELI5: How are instincts inherited to the following generation and is it possible to modificate and/ or create them? ]( URL_9 ) 1. [ELI5: How instincts biologically work? ]( URL_0 ) 1. [ELI5: How is natural instict passed through the generations? ]( URL_11 ) 1. [ELI5: How the process of mimicking is passed on through certain species. ]( URL_10 ) 1. [ELI5:How do instincts work? ]( URL_7 ) 1. [ELI5: How does animal instinct works ? For instance, how does a spider know how to make a web ? ]( URL_4 ) 1. [ELI5:How do instincts work? ]( URL_1 ) 1. [ELI5: Do we have some kind of genetic memory, similar what is presented in Assassin's Creed? ]( URL_2 ) 1. [ELI5: How do we inherit survival or psychological instincts/traits? ]( URL_5 ) 1. [ELI5: How have instincts got inscribed into our genes? ]( URL_3 )"], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/3h42k4/eli5_how_instincts_biologically_work/", "https://www.reddit.com/r/explainlikeimfive/comments/1w0fvr/eli5how_do_instincts_work/", "https://www.reddit.com/r/explainlikeimfive/comments/2du2fr/eli5_do_we_have_some_kind_of_genetic_memory/", "https://www.reddit.com/r/explainlikeimfive/comments/4ybmw1/eli5_how_have_instincts_got_inscribed_into_our/", "https://www.reddit.com/r/explainlikeimfive/comments/69lh45/eli5_how_does_animal_instinct_works_for_instance/", "https://www.reddit.com/r/explainlikeimfive/comments/3a00y1/eli5_how_do_we_inherit_survival_or_psychological/", "https://www.reddit.com/r/explainlikeimfive/comments/4w9c9d/eli5_how_is_instinct_developed_and_passed_through/", "https://www.reddit.com/r/explainlikeimfive/comments/2nohih/eli5how_do_instincts_work/", "https://www.reddit.com/r/explainlikeimfive/comments/4e5682/eli5_how_do_animals_like_ants_and_birds/", "https://www.reddit.com/r/explainlikeimfive/comments/2zw33c/eli5_how_are_instincts_inherited_to_the_following/", "https://www.reddit.com/r/explainlikeimfive/comments/4l1m46/eli5_how_the_process_of_mimicking_is_passed_on/", "https://www.reddit.com/r/explainlikeimfive/comments/30nvqs/eli5_how_is_natural_instict_passed_through_the/"]], "score": [4]}}, {"q_id": "6wyr9l", "category": "Repost", "title": "What exactly do physicists mean when they say the universe in expanding", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dmbplm2", "dmbpjg5"], "text": ["Over time, any two (significantly) distant points in the universe are increasingly far apart. There's more 'space' between them. This occurs at very large scales. For instance, our local galaxy cluster is gravitationally bound, and not expanding apart. To the contrary, we will eventually collide with another galaxy, Andromeda. But distant galaxies to which we are not gravitationally bound are all becoming more distant over time. An observer would see the same from any other location in the universe, everything distant from them moving away. > What is beyond the universe? Expansion is not meant to imply that the universe is something like a bubble, gradually filling up a greater volume. Rather, it is thought to be, although unproven to be, infinite in volume. Over time, it is becoming less dense. There's more space between objects. It is not known to be 'expanding into' anything, and we have no knowledge, nor at this time reason to believe, in an external volume which the universe is contained in or touching. As far as we have solid evidence for, the universe contains everything that exists.", "the spaces between everything are essentially getting larger. More or less without any fancy waffling about."], "text_urls": [[], []], "score": [9, 4]}}, {"q_id": "6x0knm", "category": "Repost", "title": "What keeps me from rolling off my bed at night?", "title_urls": {"url": []}, "selftext": "If I sleep alone in a Queen size bed, for example, I could theoretically fall asleep on one side of the bed and wake up on the other side. But what keeps me from rolling off entirely?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dmc5wbb", "dmc580e", "dmc61vq", "dmcve4e"], "text": ["Ever seen people falling asleep sitting upright, and then slowly slouching over until they realize it and snap to enough to sit upright again, and then fall immediately back asleep? Same thing: your body's sense of acceleration doesn't stop when you go to sleep. Your body knows and wakes up when it suddenly accelerates (like if it's about to fall off a bed). You probably stop yourself from rolling off a bed more often than you know, because most of the time you go right back to sleep and forget the whole thing.", "You never go completely to sleep at night. A small part of your brain never sleeps and always watch out for dangers. It is this part of your brain that will listen to your alarm and make you wake up. It is also making sure you do not fall off the edge of the bed.", "The brain also shuts down some motor functions to keep you from acting out all your dreams, of course this doesn't always happen (e.g., sleepwalking) and sometimes you wake up while the body is in this state which is known as sleep paralysis.", "This is actually due to evolutionary traits we picked up, they were to keep us from falling off of branches while we were asleep if you were to start leaning too far in one direction your body's reflexes would kick in to catch you and because reflexes are actually \"shortcuts\" in your neurological system your brain doesn't need to \"wake up\" to keep yourself balanced."], "text_urls": [[], [], [], []], "score": [131, 59, 13, 3]}}, {"q_id": "6x60s9", "category": "Repost", "title": "Why do games and cartoons have that obviously not-fitting/hit here/interact part of a scenario, that doesn't blend to the rest of it?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dmdc15q"], "text": ["Do you mean the color, like when in old cartoons you could tell which drawer the character was going to open because the color was slightly different on that one drawer? If so, that's because the animation is done in physical layers and to save labor the unchanging background is a single picture and the changing foreground (in this case the one drawer and the character who opens it) are different physical drawings drawn and painted by different people, so the colors do not quite match. If this isn't what you were talking about then I apologize for not understanding the question."], "text_urls": [[]], "score": [5]}}, {"q_id": "6x8qad", "category": "Repost", "title": "Why does staring at the sun make me sneeze?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dme180f"], "text": ["Because you have a photic sneeze reflex, which about 20-30% of people have. The mechanism of action is not well understood. It's possible that wires get crossed in your brain, and that the stimulus of bright light makes your brain think there's something in your nose."], "text_urls": [[]], "score": [6]}}, {"q_id": "6xd1ei", "category": "Repost", "title": "Why do humans have physical and mental limiters.", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dmezmhy", "dmez815"], "text": ["This 10% of our brain bullshit is, well, bullshit. It's a misconception from the fact that we only use 10% of our brain at any given time (that's also only partially true). The way neural networks are is that you simply can't use all the pathways for a calculation. It's like saying you'll get to work faster if you use all the roads rather than the fastest single route.", "These are both false. We'd be vegetables if we could only use 10% of our brains. Not sure where that 30% thing came from, but we don't usually need 100% of our strength to perform daily tasks. We save 100% of our strength for times when we need to lift a car off of someone who's been in an accident, for example. Adrenaline aids in those endeavors."], "text_urls": [[], []], "score": [11, 5]}}, {"q_id": "6xftpf", "category": "Repost", "title": "if the Chinese language uses characters instead of an alphabet, and there are over 100,000 Chinese characters, how do they type up things on the internet?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dmfjzvp", "dmfmhh4", "dmfmpvj"], "text": ["Most Chinese computer users type on a normal QWERTY keyboard. They type in Pinyin, which is a way to convert Chinese characters into letters. Then the computer converts it into the Chinese characters.", "Chinese type Pingyin, which is the sound/pronunciation of each character. Therefore, typing Chinese is just typing the sounds you make.", "While typing phonetically, the system automatically pops up conversion options and converts them to the actual characters you mean. It works very similar to predictive typing/autocomplete on modern English cell phones, and is just as fast and easy. Most Eastern languages have phonetic alphabets that are much smaller than the full language character set. Ex: Japanese can be represented easily in English characters, or using the 46 character kana set. Both of which easily fit on a standard keyboard."], "text_urls": [[], [], []], "score": [15, 3, 3]}}, {"q_id": "6xi5ah", "category": "Repost", "title": "How does GPS work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dmg3w38", "dmg6d7a"], "text": ["Hard to know how simple to make the explanation, but here goes. Imagine you don't directly know where you are but, somehow, you know the distances from you to New York, from you to Seattle and from you to Miami. You could get out a map and figure out where you must be. The GPS system has a bunch of satellites in orbit around the earth. Each one transmits a signal that says where it is. The signal takes a certain very short time (called the time of flight) to reach the earth's surface and that time tells you how far away the satellite is. The satellites send lots of other stuff, but the main information is location and the receiver calculates distances. Your GPS receiver picks up those signals and thinks to itself \"Hmmm ... there's a satellite that is a known distance away, and there's one that is another distance and there's another. Each satellite is telling me where it is and I know how far away it is, so I can calculate where *I* must be\". Strictly speaking, the calculation is based on the differences between the times of flight, but that is harder to visualise.", "GPS is a surprisingly simple series of time/distance 'math problem' in a lot of ways It uses the concept of trilateration Imagine this: you are trying to figure out where you are exactly in your neighborhood. You know you are exactly 1001 meters from your town center's statue. So you draw a circle exactly 1001 meters around that statue, and now you know you are somewhere on that circle. Now say you also know you are exactly 500 meters from the biggest tree in the nearby park. You draw a 500m circle around it and you find out that circle intersects the 1001 meter circle in a couple of points. Now you have narrowed yourself down to a couple possible points, but you still aren't sure. Now let's say you know you are 750 meters from another landmark: this third circle is drawn, and now you find where all 3 circles intersect. Now you know where you are. That's the basic concept behind GPS: satellites in space broadcast a signal. That signal is received by your GPS receiver and decoded. It then tries to find out where you are. But you have to solve a new problem: How far are you from that satellite? But that opens up new problems. Since satellites move, where was that satellite? How does your receiver know? Basically, these satellites broadcast who they are (which satellite is sending the signal) and time data. To calculate how far you are from the satellite, you take a known constant - the speed of light - and multiply it by the time difference between your receiver and the time data the satellite is sending. That gets you a distance. But wait - how do you know where the satellite was that sent that signal? What if your own receiver's time is wrong? Your calculation on distance would be way off! So your GPS receiver has an 'almanac' that lists the status and when and where a satellite will be, as their orbits are managed from the ground. Using this data, you can now pick up a signal from say, satellite 34, and know approximately where its position is in space. You aren't sure where you are, but you can take its signals and start calculating some possible solutions. These GPS signals also contain a timestamp close to when it was broadcast, so your receiver goes \"oh, I'm on the wrong day, let me fix that\" and takes the GPS date and time and says \"hmm, well I'm probably pretty close to the time I'm receiving\" By doing that, it is \"aligning\" itself to the satellites, and as it receives signals from multiple satellites, starts refining its data to get an accurate GPS time from which it can use its almanac and the satellite's own position data that is broadcast and figure out which GPS satellites are where, and thus get an accurate distance to each satellite and thus find an accurate location. The other neat thing is that GPS satellites broadcast almanac data too, to update receivers as GPS satellites aren't static objects and need to be maintained or reposition or what not. Thus, the next time you turn on GPS in your car or on your phone, you'll see it take some time to start up and get your location accurately. And that's because it's doing all those math calculations in its processor to figure out where it, and thus you, exactly are. PS - fun trivia: GPS was originally designed by the US military to help US Navy ballistic missile submarines get an accurate location on where they were on Earth to launch nuclear tipped missiles at a moment's notice. Think about that next time you use it to tag your location"], "text_urls": [[], []], "score": [6, 3]}}, {"q_id": "6xjvbo", "category": "Repost", "title": "Benefits and drawbacks of universal healthcare vs privatized?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dmgi0pq"], "text": ["Watch Michael Moore's documentary Sicko. It does a great job explaining these things. In essence, most of the \"issues\" with socialized medicine are lies told by people who are paid off by the insurance industry. The quality of care in places with socialized medicine is as good as the US, easily. The only real issue with socialized medicine is that there are sometimes waits on non-critical surgeries, but anyone who wants to get it outside of the system is free to do so at their own expense. Furthermore, if the US were to socialize it's system with the current amount of money we all pay for medical care including insurance, you could probably eliminate the wait time problem entirely with the only limiting factor being the number of doctors. Most of the costs in our current healthcare system are due to corporate desire for profit rather than true expense. And finally, the vast majority of doctors don't go into medicine because of the pay. This is because, A, most of them just want to help people, and B, most are paying off ridiculous amounts of student loan debt and also have to pay a ridiculous amount of money for malpractice insurance. So really it kind of evens out for the doctors in the end, well, except that doctors in socialized countries get to help more people"], "text_urls": [[]], "score": [3]}}, {"q_id": "6xkyas", "category": "Repost", "title": "Why is it when you need to take a dump really bad, that the closer you get to the toilet the harder it gets to hold it in?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dmgo915"], "text": ["Someone will definitely post a better answer. But here's this for now.... I think* it's a similar situation to why it's recommended you only use your bed for sleeping. Your brain passively identifies your bed as a spot for sleeping, which makes falling asleep easier. Or even just thinking of your bed may make you sleepy. Likewise, because you regularly use the toilet for pooping/peeing. Your brain passively knows you're on your way there and may begin some of the bodily responses to prepare for the poop.."], "text_urls": [[]], "score": [10]}}, {"q_id": "6xm4c6", "category": "Repost", "title": "Please educate me on how data is stored inside metal and how computers work", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dmgvmo8"], "text": ["Imagine a hard drive as a piece of squared paper. Each square represents a bit. The data is written in the squares in binary code (with 0s and 1s). If the square is filled, it's 1. If it's striped, it's 0. If it's empty, it's available space. Now, the actual hard drive has a platter with tiny magnetized regions. Each region represents a bit. If a region is magnetized in North polarity, it's 1. If it's South, it's 0. That data is transferred to and processed by central processor. It \"understands\" binary code and EXEcutes commands to process the data and/or send the results to output devices (display, speakers, printer, etc)."], "text_urls": [[]], "score": [4]}}, {"q_id": "6xnct7", "category": "Repost", "title": "Why do we have Daylight Saving Time, and why does Arizona ignore it?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dmh47fp", "dmh9fq1", "dmhevy5"], "text": ["This is a good article and has some good links with studies. From the article: \"According to an Arizona Republic editorial from 1969, the reason was the state's extreme heat. If Arizona were to observe Daylight Saving Time, the sun would stay out until 9 p.m. in the summer (instead of 8 p.m., like it does currently).\" URL_0", "It saves on energy because people spend more of their awake hours in daylight. So that's one less hour of electricity used for lighting. During times when energy conservation was particularly important--World War II and during the 1970s energy crises, for example--the US went on daylight savings time all year round. There was a measurable effect on energy usage during those times. So sure, no, nobody gains or loses anything, the earth continues to rotate irrespective of what time it is. But that's not the point of the change.", "DST is a way to use better daylight hours, as they change in winter/summer. What this means is that you will have your \"active\" hours inside daylight hours instead of having some active hours at night, having lights on. This is specially necessary in countries far from Ecuador line, were daylight hours change significantly It was thought to save energy, but should be more flexible in my opinion. Edit: I don't know why Arizona ignored it. Do they have 24 hours of bright sun every day?"], "text_urls": [["http://www.abc15.com/news/state/daylight-saving-time-spring-2016-why-arizona-doesnt-observe-daylight-saving"], [], []], "score": [9, 6, 3]}}, {"q_id": "6xqqld", "category": "Repost", "title": "- how do people solve Rubick's cubes so insanely fast?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dmhsbd3", "dmhs6t2"], "text": ["Rubiks cubes are pretty cool when it comes to how mixed up a cube can actually be. No matter how long you spend altering a cube it will never be more than 20 face turns away from being solved. This means that if you know all the rules to solving them, its just a matter of how fast your hands can move.", "Algorithms. They memorize and practice them until eventually there is no need to look at a cube while solving, hence the \"inspection\" time they are given at competitions. They look at the cube, find the correct algorithm, and solve it, all in the span of a bout 10 seconds."], "text_urls": [[], []], "score": [8, 4]}}, {"q_id": "6xtoqo", "category": "Repost", "title": "For over 15 years, every week we hear about breakthrough medical and science discoveries that are going to change the world soon. Like cancer getting cured and all kinds of stuff like that. Why aren't we seeing any of this in practice / commercially available?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dmid2jd"], "text": ["Because newspapers sensationalize science, often taking one small detail out of context and making it a headline. But thats not how science works. Especially for anything thats used on humans. It can take decades of testing, and any potential issues means something isn't viable for human use and gets scrapped."], "text_urls": [[]], "score": [5]}}, {"q_id": "6xxmfo", "category": "Repost", "title": "Why can wild animals eat other animals raw but if humans try it we get sick?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dmj7tlv", "dmj8418"], "text": ["We don't get sick from the rawness of the meat, we get sick from the microbes and such that can reside is raw meat. Cooking tends to kill that stuff. Animals get sick from raw stuff, too. Have you ever had a dog who ate a rotten mouse? Get ready for some upset stomach action and explosive diarrhea.", "But we can and do eat raw meat. Sushi, sashimi, poke, beef Wellington, raw venison, etc. I just ate some bomb raw yellowtail the other day. As long as its fresh and free of bacteria and parasites you're good. It's not the meat that makes you sick, its contaminated meat."], "text_urls": [[], []], "score": [6, 4]}}, {"q_id": "6xxn2y", "category": "Repost", "title": "With everyone having a cell phone and constantly texting, why aren't we able to text 9-1-1 operators? In life threatening situations, you may not be able to actually speak on the phone.", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dmj7kx5"], "text": ["Yo ho ho! Yer not alone in askin', and kind strangers have explained that it's being implemented now: 1. [Can you text 911? ]( URL_2 ) 1. [Does texting 911 work the same way as calling? ]( URL_1 ) 1. [ELI5: Who doesn't 911 Services not have a way to contact them through text? ]( URL_0 ) 1. [ELI5 Why isn't texting 911 a thing yet? Are there technological issues stopping it from happening? ]( URL_5 ) 1. [Can you text 911? ]( URL_4 ) 1. [ELI5: What's the hold up with the ability for residents to text 911 for emergencies? Is it a technology-related problem? Jurisdictional? ]( URL_3 )"], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/5x0cf5/eli5_who_doesnt_911_services_not_have_a_way_to/", "https://www.reddit.com/r/NoStupidQuestions/comments/6m65ze/does_texting_911_work_the_same_way_as_calling/", "https://www.reddit.com/r/NoStupidQuestions/comments/648dmn/can_you_text_911/", "https://www.reddit.com/r/explainlikeimfive/comments/5oya18/eli5_whats_the_hold_up_with_the_ability_for/", "https://www.reddit.com/r/NoStupidQuestions/comments/2nc5ti/can_you_text_911/", "https://www.reddit.com/r/explainlikeimfive/comments/3ok1p6/eli5_why_isnt_texting_911_a_thing_yet_are_there/"]], "score": [8]}}, {"q_id": "6y0s4o", "category": "Repost", "title": "Why do wind turbines have 3 blades?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dmjtmvf"], "text": ["This is because when one blade is in the horizontal position, its resistance to the yaw force is counter-balanced by the two other blades. So, a three-bladed turbine represents the best combination of high rotational speed and minimum stress. Mind you the early models all had two blades and some remaining one or two megawatt sized turbines still have just two blades. This was due to the technology and materials at hand at the time. 30 years ago, two government standard blades weighed 50 tonnes. Today, 3 regulations blades weigh 51 tonnes. Some pretty good advancement has been made in the field."], "text_urls": [[]], "score": [8]}}, {"q_id": "6y14u0", "category": "Repost", "title": "Why are most cop cars the same model? I know they switch the engines but what's so desirable about the car model itself?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dmjwb35", "dmjw94c"], "text": ["They're \"fleet vehicles\". All built on a fairly bare chassis with not a lot of options and sold at a volume discount. And having the same make and model of vehicles means you don't have to keep various versions spares for a bunch of different accessories like light bars or laptop mounts.", "Car manufacturers make specific models of cars that are intended to be used as cop cars and market them to police forces across the country. These cars tend to have upgraded engines and suspensions. They come pre-installed with things like push bars on the front, searchlights and screens to separate the front from the back. There are only a few models of these cars around. For a long time the most popular model was the Ford Police Interceptor which was an upgraded Crown Victoria. That model is no longer being produced and newer police cars are a little more diverse."], "text_urls": [[], []], "score": [4, 3]}}, {"q_id": "6y5tte", "category": "Repost", "title": "Why do car companies have different names for cars in various regions? Like the the Toyota 86 is called that in NA, where it's called the GT86 in Europe?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dmkyd38", "dmkyxal"], "text": ["Usually because some words don't work well in some markets. Examples: * Honda Fitta became Honda Jazz in Sweden, because \"fitta\" is the Swedish equivalent of \"cunt\". * Mitsubishi Pajero has a different name in some countries, because in Spanish (or maybe it was Italian, don't remember), Pajero means \"fag\". Sometimes, it's because a car is re-branded. Say, for example, that Chevrolet needs a small car for the US market. They don't have such a car in their lineup, don't have time to develop one, and they aren't good at small cars anyway. So, they buy cars from another manufacturer, and put their own name on them. So, for example, Suzuki Ignis is marketed by GM as Chevrolet Cruze. People who wats to buy American buy a Chevrolet and think they get an American car.", "Sometimes the name directly affects sales. When Ford released the Pinto in Brazil, nobody bought it. This is because the word \"pinto\" (pronounced peen-cho) in Portuguese means \"tiny dick.\" They renamed it to Corcel."], "text_urls": [[], []], "score": [10, 3]}}, {"q_id": "6y6a05", "category": "Repost", "title": "What does it mean when a company throttles data, what is throttling?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dml0d6u", "dmkzb95"], "text": ["It's slowing down the transfer of data, such as downloads, websites, etc. Sometimes everything you access, sometimes just something specific like bittorrent. For instance, suppose you're on a phone plan. The reddit frontpage right now is 1.8MB. This is 1.8 * 8 = 14.4 Mbit. If you have a 10 Mbps connection, this will take 1.4 seconds to download. That is, if you go to URL_0 , it will take 1.4 seconds to transfer all the data needed to display the page. Now suppose you have a 10GB limit per month, and after you reach it you're throttled to 64 Kbps. Now the frontpage takes almost 4 minutes to download.", "Depending on what your doing or how much data you have used a service provider will drop your bandwidth to a significantly slower speed. So the big open internet problem is that if you wanted to watch Netflix but if the internet wasn't open an ISP could essentially severely limit your speed to Netflix, either because you didn't pay for high speed access to Netflix or because Netflix didn't pay for a fast lane to customers for that ISP. Or say for instance you have an unlimited cell phone data plan but you're using like 32 gb of data a month, they could drop your data speed because you're basically hogging a lot of bandwidth all the time."], "text_urls": [["https://reddit.com"], []], "score": [3, 3]}}, {"q_id": "6y9qol", "category": "Repost", "title": "The Doomsday Clock. What is it's purpose if it's always at around 5-to-twelve since before the Cuban Missile Crisis? Does it actually serve a purpose or reflect any real measurement or is it just a whistle-word for headlines?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dmlnxmi", "dmlo4nr"], "text": ["It's not meant to represent time in a literal sense. It is meant to represent how close the world is to a man-made global catastrophic event happening. Time is simply used as an analogy for social/political/other factors, as in \"less time left\" = \"greater danger.\" Close to midnight is thus \"Close to a dangerous event happening/lots of risk\"", "As Dr. Manhattan said. And I'm somewhat paraphrasing. I would argue that a symbolic doomsday clock is as nourishing to an intellectual, in the same way as a picture of oxygen is to a drowning man."], "text_urls": [[], []], "score": [15, 12]}}, {"q_id": "6yaisw", "category": "Repost", "title": "Why if I were to shut a box made of mirrors in a light room, and then open it again in a dark room will no light come from the box?", "title_urls": {"url": []}, "selftext": "There must be a good reason that I just can't think of, but shouldn't in theory the light just keep bouncing from mirror to mirror until the box is opened?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dmlu60j", "dmlucjw", "dmlu61r"], "text": ["Mirrors don't perfectly reflect all light, they absorb a small percentage of it. If each bounce absorbs 0.1% of the light, then after 10,000 bounces, basically none of the light is left (0.0004%). In a small box, 10,000 bounces of light will happen in a microsecond or less!", "In theory, light will come out in a blink. In practice, this will not happen because there is always loss in mirrors.", "Mirrors don't reflect perfectly. It absorbs a tiny amount of the light every time it bounces. You can see this with mirrors facing each other - the reflection will turn slightly green after several bounces. Light travels at the speed of light so it completes about 10 billion bounces before you can even blink your eye. The light will be completely absorbed the second you close the box."], "text_urls": [[], [], []], "score": [13, 3, 3]}}, {"q_id": "6ybhsb", "category": "Repost", "title": "Why do computers still ask us to \u201cSafely Eject External Storage Device\u201d? Does ejecting unsafely really risk damage to files or the device?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dmm360l", "dmm31zf"], "text": ["Yes, it's still necessary. If you copy a file onto an external hard drive or flash drive, the program you're using (let's say windows explorer) will display a copy dialog and progress bar showing the copying process, and then show that it has completed. However, windows explorer is not directly copying the file itself, rather it's communicating with the operating system, Windows in this case, which is handling the nitty-gritty of the copying. While Windows might report to explorer that the copying is finished, Windows itself may not be done actually writing the new file behind the scenes. It's essentially just telling explorer \"I don't need anything more from you, I can handle it from here\". If you pull the drive out at this point, you may end up with a corrupted or incomplete file, or the entire file system could become corrupted. By safely ejecting it, the operating system ensures that everything is completed before the device is removed.", "In the good old days, if you pulled external media without going through some unmounting procedure first there was a chance the files would still be in cache to be written to the media as opposed to actually written. So a file might end up corrupted, or the disk may need formatting, depending on where the write was. Un-mounting or ejecting the media would flush any write cache and make sure everything was set on the disk."], "text_urls": [[], []], "score": [13, 3]}}, {"q_id": "6yey3e", "category": "Repost", "title": "How do they know that nothing can go faster than the speed of light?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dmmubcn"], "text": ["I'd suggest you read this [excellent post]( URL_0 ) by u/Astrokiwi over at r/askscience, who gave a really good answer to this question"], "text_urls": [["https://www.reddit.com/r/askscience/comments/6vokay/how_did_einstein_work_out_that_the_speed_of_light/dm207bz/"]], "score": [5]}}, {"q_id": "6yeysj", "category": "Repost", "title": "Why are courtroom sketch artists still a thing? While I understand not wanting live broadcasts, why are courts still in the dark ages insofar as refusing to allow still photos for historical purposes?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dmmtnuj"], "text": ["I'm assuming here that you're talking about countries outside the USA, where courtroom photos are legal. In the UK, courtroom photography and filming are not permitted because live shots of suspects and trials could result in fallacious information being released to the \"outside world\", potentially resulting in courts being defamed and in the worst case resulting in a mistrial. *edit* it is also due to the likelihood that suspects will be less willing to admit guilt or submit verbal evidence if cameras are in the courtroom."], "text_urls": [[]], "score": [4]}}, {"q_id": "6yg0v8", "category": "Repost", "title": "why can't there be cars that look as cool as lambos, but with cheap components to make them as cheap as a regular Honda", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dmnaau2", "dmnd07d", "dmn220t", "dmnb84u", "dmndwk4", "dmn9g5c", "dmn1zox", "dmndn66", "dmnbvql"], "text": ["A lot of comments are missing another factor: Car companies don't *want* their cheap cars to cannibalize sales of their high-end sports cars. Let's suppose for a moment that they are in fact able to make a Dodge Dart look like a convincing Ferrari without increasing the cost. Further, let's suppose that people wouldn't heap disdain on the fancy-looking Dart for being a shitty car posing as a nice one. Both of those things are probably iffy prospects, but not outside the realm of possibility. That would be a great thing for Dodge, right? Except, Fiat owns both Dodge and Ferrari. So what they've actually done here is to replace some of the sales of a $2-400,000 car which probably earns them $50,000 or more in profit, with a $17,000 car that earns them probably closer to ~~$1500~~ $200 profit. These companies aren't *supposed* to compete with each other. Edit: As several have mentioned, I was probably overestimating the profit margins on the low end. Honestly the correction only makes this logic more compelling.", "There's a multitude of reasons. I'll cover what I think are the major ones: 1) Supercars are impractical 1a. Most tend to be 2-seaters with not much room for cargo. People who drive supercars don't care about practicality as much as us 9-5ers because generally the supercar isn't their primary mode of transportation (or they have other ways to get around the limitation such as having other people to deal with moving their luggage from one place to another or just buying everything new at their destination) 1b. Supercars are low With a lot of them, even going over a normal speedbump in a parking lot is a challenge. 1c. Supercars have intricate, delicate bodywork Tap your Honda's bumper into a wall or hit a tall curb with it and it's probably no big deal. It's made to take a bit of abuse. In a supercar that would be some cracked carbon fiber or fiberglass 2) Supercars are kinda big 2a. Supercars are generally somewhat long with a wide wheelbase On an economy car with a smaller engine that would hurt acceleration and gas mileage. Plus it'd be a pain to park (This could almost go under impracticality) 2b. Supercars have big engines Economy cars have small engines in general, because if you can't afford an expensive car you probably can't afford a ton of gas either. Supercars have no such constraints, so they tend to be bigger with a wider wheelbase and make up for the weight with more power (They also mitigate their weight from their large size by using expensive lightweight components) Put all that together and you get a situation where nothing in the economy market *quite* looks like a supercar. A lot of things have some elements of supercars though: The 1st generation Toyota MR2 ( URL_0 ) had 2 seats, not much room for cargo and lots of sharp angles. But it had a relatively sane ride height and bumpers that wouldn't crack at the slightest provocation. The current generation Honda Civic Si ( URL_1 ) has all sorts of crazy angles and vents on it that are typically reserved for much more expensive cars, but the format is a 2-door 4-seater with a decent trunk. That makes the overall shape look a lot more \"normal\" There's lots of other stuff to mention such as engine placement and the effect that has on the overall shape of the car (and how that contributes to the impracticality). Going to quit here before I write a novel, though.", "There kind of are (see: [kit cars]( URL_0 )), but the problem is that nobody really wants them enough for it to be a viable large-scale market.", "There are, sort of, they're called kit cars. Kit cars are often laughed at in the car world because it's like wearing a fake Rolex and often times they're lacking quality. The companies that make them don't have/can't afford to use things like carbon fiber and even the really nice ones only look legitimate from about 50 feet away. Most super cars are made of very expensive alloys and carbon fiber. The attention to detail as well as the materials are what really makes them so expensive. The only exception I can think of is the Shelby cobra kit cars, but they're still expensive. You get what you pay for.", "A perfect example here is the new [Corvette]( URL_1 ) It is often compared to the [Ferrari 488]( URL_0 ;) I'm sure you can see why. The new Corvette is a quite capable sports car, and could actually run with Ferrari's on a track (although it would probably lose). The Corvette costs $55,000, while the Ferrari costs $250,000. Why? One aspect is the interior. I've driven a Corvette: The inside is all cheap plastic and Best Buy-esque navigation systems. Beyond that, there are tons of small details Ferrari paid attention to that Chevy didn't: Weight, balance, fitment, quality of parts, etc. So, you can get a car that is (most of) a Ferrari for 1/5 the cost. The remaining ~$200,000 goes into that final 10% that makes a Ferrari one-of-a-kind.", "There are plenty. It's just people go by price in rating them cool. a Honda S2000 is every bit as sleek as a Jaguar, but since it's way cheaper, people see it as cheaper.", "Part of what makes them look cool is that they're expensive and you can't get around that. You can definitely tell the difference between a $100 suit, and a $1000 suit, right? even if the $100 suit tries its hardest to emulate the $1000 suit. Sometimes quality can't be matched without $. So Honda may try to emulate Lamborghini's paint lets say, but it won't look exactly the same or else it'll drive the price up. Lamborghini doors for example. Regular cars are hinges while the vertical door needs a hydraulic or else it won't stay up. Those are more expensive than regular hinges. So even if they wanted to, they couldn't make it so it's as cheap as a regular Honda. Also must think of technology. Exotic vehicles can put cutting edge tech in their cars because they'll throw the $2500 piece of tech into the price because $ isn't an option for ppl buying lamborghinis. Honda will wait until the tech is cheap enough to include it where it won't hike the price of the vehicle up.", "A lot of the things that make Lamborghinis look cool also make them impractical. They are small and low with the engine behind the driver and with no back seat. Their sloping roof lines limit headroom. They have laughably small trunks. They are difficult to see out of. If you want to build a cheap car that will sell you need to make it higher off the ground so people can easily get in and out of it, so they can have a good view of the road and so they feel like they are high enough up to be safe. You need to make the passenger compartment taller - there needs to be a lot of headroom and useful storage space. You want to put the engine in the front because it's cheaper to manufacture and because it leaves the back open for a large back seat and a large trunk that can be made larger by folding down the rear seats. You can buy relatively inexpensive cars that look cool. Mustangs are designed to look cool and they aren't all that expensive. But, just like Lamborghinis, they sacrifice practicality in favor of looks, so most people buy practical sedans or SUVs instead.", "I've felt like this about old muscle cars for a long time now. Why can't I just have a 2010 corolla that looks like a 69 nova?"], "text_urls": [[], ["http://imgur.com/gallery/SwLiUPu", "http://imgur.com/gallery/XugAg"], ["https://en.wikipedia.org/wiki/Kit_car"], [], ["http://car-configurator.ferrari.com/titan/TitanServicev1.aspx?RenderScript=f142m&amp;width=1500&amp;height=800&amp;base64off=&amp;workingWidth=1500&amp;workingHeight=800&amp;option=*EXT/065427400,*EXT,ECN,CER,BRA,WHR,WHB,EC,WH,*INT/364018500,*INT,CMM,SEA,CSB1/364700800,CSB1,SS3,SSS,SSB,*CAR/364900152,*CAR,CP1,CPC,REV,IOR,CM,SS,CP,IO,STDStitching,STDRoof,STDDSH7,VRDashInserts,STDSteering,VRSWInserts,STDDash&amp;format=jpeg&amp;quality=95&amp;assetPath=EXT_TURN/000&amp;replace=frame:00&amp", "http://st.motortrend.com/uploads/sites/10/2015/09/2015-Chevrolet-Corvette-Stingray-front-drivers-above-view.jpg"], [], [], [], []], "score": [222, 107, 57, 13, 10, 8, 7, 7, 3]}}, {"q_id": "6yj0lm", "category": "Repost", "title": "Why do shallow injuries (e. g. paper cuts) often seem to hurt more than deeper ones?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dmnr55g"], "text": ["The vast majority of nerve endings are at the surface of skin. Deeper into your skin, you're not as sensitive to pain. Also, deeper in your blood will clot and provide a protective layer for the nerves there, while at the surface paper cuts typically don't cause much blood."], "text_urls": [[]], "score": [3]}}, {"q_id": "6ymf8l", "category": "Repost", "title": "Why do we have to drink water?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dmognlk"], "text": ["We release water through are skin as a cooling mechanism (sweat), many of our cells use water in reactions that are essential for our function and we use water to carry away unwanted stuff (piss), among many other uses of water. All of these mean that if your body isn't supplied with water it struggles to function. Your blood becomes more concentrate with unwanted chemicals as your kidney tries to maintain moisture by not producing urine, as a result your entire cardiovascular system has to work harder to keep blood circulating. Your brain tissue is reduced temporarily, reducing your ability to think and react. For more severe cases simply moving too fast can cause you too faint as your blood is circulating nutrients so poorly."], "text_urls": [[]], "score": [3]}}, {"q_id": "6ymque", "category": "Repost", "title": "How USA, a 300 years old civilization, became so quickly one of the strongest civilization in the world?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dmoiacv", "dmojn1a"], "text": ["USA didn't start from scratch. It was founded on the shoulders of people who had been \"civilised\" for centuries. And if you're asking yourself how quickly after foundation it became such a powerful nation (merely 200 years). That's not a record. Spain holds the record with \"a few months\". 1492 was a good year.", "There are a host of reasons, but geographic isolation, rich natural resources that allowed self-sufficiency, and political stability seem most important. **1. Geographic Isolation.** The United States is geographically isolated from major potential enemies. It has a northern border with a small friendly nation, and a southern border with a small usually friendly nation. Its major competitors have to cross an ocean if they want to invade, which is incredibly difficult. **2. Natural Resources.** Land for food and growth, minerals, timber, oil, coal, you name it, American has it. Because of the resources the country's economy has always been robust and able to change and expand, while it has not relied on any foreign nation for the entire supply of any needed resources. **3. Stability.** This might be the most important factor. The United States never had an aristocracy, it never had royals fighting for power, never had warring factions constantly on the brink of internal strife. Apart from the Civil War, the political structure has been stable and constant, the legal system has provided for reliable conflict resolution, and the criminal justice system has ensured relative tranquility and safety. A lot of countries have not had this, or have not had it with such consistency."], "text_urls": [[], []], "score": [8, 3]}}, {"q_id": "6yn6tl", "category": "Repost", "title": "Why can't we be our own ISP?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dmolssn", "dmolwy3", "dmoloni", "dmolpxt", "dmolzxi"], "text": ["> What's keeping us from just getting the internet to us directly from wherever it comes from? Because there isn't a connection to your house directly from the Internet backbones. > What does an ISP do? They connect you to the internet. They own the physical lines that go to your house that you can connect to the internet from. If you end your service with them, you can't use their equipment or infrastructure. EDIT: As an analogy. Think of roads and re-ask the question: \"What's keeping us from just getting on the Interstate to us directly from our house? What do local roads do?\" The answer is: you can just build your own private road directly to the Interstate, but there are lots of issues preventing this: you probably don't have the resource to make your own roads; you don't own all the land between you and the Interstate; you would still need permission to connect to the Interstate.", "You can certainly be your own ISP. All you need to do is lease a fibre from a phone company, or get city permission to dig a trench and lay your own fibre from your house to a peering point nearby. Then you need a carrier class boundary gateway router, about $125,000, to connect to all your peers without slowing them down. You're set, no more pesky fees, no spying on you, no filtering. Alas, you also have no money.", "The internet doesn't come from any one place. It's simply a bunch of different networks all hooked together, hence the name (Inter-network). What your ISP does is provide connections to other networks. They negotiate agreements with other network providers who are, in turn, connected to yet more networks. Through this system of interconnected networks you are able to talk to any device connected to the internet. There's technically nothing stopping you from running your own ISP but it would be technically and economically difficult. You would need to negotiate at least one connection to a major network provider to allow you to send and receive data to and from the larger internet. Most large network providers aren't going to waste time with an individual home user. They would rather sell very large connections to an ISP and then let the ISP handle the work of dealing with individual customers.", "The Internet is a worldwide network of networks. You can't access the Internet without ISPs being involved because ISPs *are* the Internet. They are the organisations that connect private networks like your home network or corporate networks to each other. If you wanted to be your own ISP you'd have to make a deal with a higher tier provider (essentially an ISP that connects multiple ISP networks together) to allow your network to connect to their's.", "An ISP has a connection to really high speed Internet, the kind that links with fiber optics. Yes some ISP's have fiber optics to the door. It is too expensive to be a standard solution. So buy routers and ways to connect. Fancy routers not available in your store. Then get someone competent to connect you. The closes thing I know to this is a system set up on an island in the state of Washington. Residents on the island wanted high speed Internet which no local ISP was willing to provide. These were well to do technically savvy residents. They established a microwave link to the mainland and put in a system of routers on the island. They charged dues to pay for the system and a local retired resident took care of local maintenance."], "text_urls": [[], [], [], [], []], "score": [15, 9, 7, 3, 3]}}, {"q_id": "6yv0bo", "category": "Repost", "title": "How do computers convert binary into instructions?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dmqbvah"], "text": ["This is the task of the CPUs control logic. All these transistors that make registers, busses, adders and the other fuctions of the CPU is controlled by single bit control signals. So you may have hundreds of these signals in a core. The control logic is a block that converts the instructions you feed the processor into these control signals. There is also a counter per instruction so that one instruction can take multiple cycles. The control logic can be made in different ways. The simplest way to think of it is as a read only memory which takes the instruction in as address input and outputs the data at that memory location as the control signals. However this is inefficient so they usually have ways to reduce the space requirements of this logic and end up with an FPGA or something similar. If you want to know more I recommend a youtube series by Ben Eater where he builds a very simple CPU using simple logic components."], "text_urls": [[]], "score": [3]}}, {"q_id": "6yw82b", "category": "Repost", "title": "How does Google Maps know about traffic in specific locations?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dmqlvd8", "dmqlsz3"], "text": ["It is fairly accurate. Your phone knows where you are (thanks to GPS) and can extrapolate how fast you are moving between GPS pings (if you travel about 5,000 feet in a minute, you are going about 60 mph). Since there are a great number of phones all transmitting this information back to Google, Google has a good sense of what the traffic is on major roads at any given point in time.", "Google integrates traffic data from multiple sources. For some regions they get data directly from the Department of Transportation. Google also combines this with real time information from people using their smartphones with location tracking turned on."], "text_urls": [[], []], "score": [16, 6]}}, {"q_id": "6yzcvc", "category": "Repost", "title": "Why do birds bob their heads as they walk?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dmrbuv0"], "text": ["It's a stabilization method for their eyesight. Since many birds are prey to other animals, they have to be constantly on the lookout. Bouncing their heads up and down when they walk like we do would make it very hard for them to pay attention to anything, especially since they can't lock focus like we can. So instead, they keep their head still as their body moves forward then very quickly bob their head into the next position. So overall, the cumulative time moving their head, and therefore not on the lookout for predators, is reduced to one quick bob rather than a bunch of up and down movements."], "text_urls": [[]], "score": [5]}}, {"q_id": "6z0rll", "category": "Repost", "title": "How is open source software more secure?", "title_urls": {"url": []}, "selftext": "Since I can see the whole code, if, say, I find a vulnerability, cant I just exploit it?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dmrlwdr"], "text": ["You could certainly exploit that vulnerability, but because everybody can also see the code, there's a good chance someone else has also noticed that vulnerability before you, and steps to correct it might already be in progress. Additionally, with open source code, it is often far easier to get in touch with the developers and report issues directly to them than it is with closed-source projects. As a result, security issues can sometimes be resolved faster. With most open-source code, the public is often allowed and encouraged to submit code improvements directly to the developers. So someone could submit the code to fix a vulnerability as a part of them reporting an issue"], "text_urls": [[]], "score": [3]}}, {"q_id": "6z2c0t", "category": "Repost", "title": "How come almost everyone (human) in the world has diffrent faces, yet almost all (Let's say deer) look alike?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dmrxj4t", "dmrx7nn"], "text": ["Humans are exceptionally cooperative creatures and that seems to be assisted by facial communication. We have recognition systems finely tuned for human facial expressions so we are very sensitive to them compared to other creatures. We also have much more expressive and varied faces because that is an important way that we communicate. Other animals don't cooperate in this way and it follows that they don't need their faces to communicate information to each other, so they are less expressive and varied. So it is two-fold. Animals haven't evolved to look as different as humans and our brains aren't attuned to the differences in animal faces like we are to differences in human faces.", "This has to do with how we are good at recognising each other's faces because we routinely interact with other humans for comfort and survival. If we interacted with deer as regularly, and if our survival counted on it, we would be able to recognize specific markings and differences in deer. So the deer really just all look alike *to us*"], "text_urls": [[], []], "score": [6, 4]}}, {"q_id": "6z4fwp", "category": "Repost", "title": "why do people get the munchies when they smoke weed?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dmseahm", "dmsi5zf"], "text": ["Hunger is a side effect of the drug, my man. THC binds to two receptors in the human body, creatively named cannabinoid receptors 1 and 2 (CB1 and CB2 for short). CB1 is located in several places throughout your body, including your brain and your GI system. When THC interacts with CB1 in your brain, it has psychotropic effects including euphoria (it gets you high). In the GI tract, CB1 normally helps to regulate food intake, so when THC meets the receptor there, it causes you to feel hungry.", "The simplest explanation I had always heard was that THC increases sensitivity of your senses. It doesn't necessarily \"heighten\" them, it just makes you perceive them more. For example, your hearing doesn't actually improve, but the things you do hear feel louder. So things that usually taste good, now taste amazing, and it makes you crave more tastes. This paired with the fact that THC also inhibits the stomach from sending the \"I'm full\" signal to the brain means you never really feel satisfied from eating while high, and can eat until you burst."], "text_urls": [[], []], "score": [12, 3]}}, {"q_id": "6z6dba", "category": "Repost", "title": "Why does turning it off and back on solve the problem in a lot of cases?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dmsuxmv"], "text": ["What I tend to explain is that when your device or computer goes through a shut down sequence it is similar to you going to sleep at night or leaving your house before a vacation. The devices operational steps of shutting down include turning off services such as location, wifi, Bluetooth, cellular data as well as ending process' for other systems (RAM in particular in computers and smart phones,) which otherwise would be akin to leaving your car on and running overnight. When the device or computer turns back on most machines or devices go through a power on systems test which makes sure all components are on or able to be turned on as it powers up. This process will also turn or kick previously not functioning services back into a working condition."], "text_urls": [[]], "score": [3]}}, {"q_id": "6z7vdc", "category": "Repost", "title": "Why does rubbing your eyes when they're closed make you see a bunch of different coloured lights?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dmt5yrt"], "text": ["The phenomenon is known as 'Phosphene'. It happens because your retina can be stimulated by physical pressure as well as my actual light. I'm not quite sure why this is the case but I hope this helps."], "text_urls": [[]], "score": [3]}}, {"q_id": "6z8sw6", "category": "Repost", "title": "Why do you crave more cigarettes whilst drinking alcohol?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dmtet0u", "dmtjd72"], "text": ["They're the same cravings, you just have fewer defenses against them. Alcohol impairs executive functioning, the \"grownup\" voice in your brain. At this very moment, your pleasure sensors would like nothing more than for you to do all kinds of stupid shit that would bring on a hit of dopamine. Assuming you're sober, your executive functions modulate and suppress those urges. After a few drinks, not so much.", "They interact strangely. Both normally get your brain to release dopamine (the reward chemical). However smoking actually suppresses dopamine when you are drunk,causing you to drink more and smoke more in an attempt to compensate. Edit: here's a study on this, it focusses mainly on the increased drinking, but also answers your question re-cigarettes: URL_0 Also, as others have pointed out your normal cravings are harder to resist and there is an element of state-dependent behaviour, where you have previously associated the two activities."], "text_urls": [[], ["https://www.sciencedaily.com/releases/2013/07/130718130615.htm"]], "score": [121, 20]}}, {"q_id": "6z9jq8", "category": "Repost", "title": "Why does coming back from somewhere always seem shorter than the trip there?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dmtigxr"], "text": ["I heard an explanation for this a while ago, I'll try to do it justice but I don't know all the scientific terms behind it So when you're going somewhere brand new your brain is taking in all the details, and forming your picture of the area. It seems longer because your brain is working harder to perceive everything about it. On the way back through it you already have those details, so your brain is recalling them as opposed to forming the memories, which uses less power, and feels like it takes less time"], "text_urls": [[]], "score": [5]}}, {"q_id": "6zehiy", "category": "Repost", "title": "Why does gravity affect time?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dmurlks", "dmumr5y", "dmun5t2"], "text": ["In presence of gravity the space dimension is stretched. Similar is the case with time (because they are directly correlated even though they are still their own individual dimensions), time also gets stretched (more accurately, curved) in presence of gravity. In other words, time runs slower in presence of gravity. The more gravity you have, the slower time passes. (Also like others have stated, like many things in science we know the how, but we don't know the why. We don't even know *what gravity is*, so let that sink in. I mean gravity is effect mass has on space time, but I'm not an astrophysicist so I'm not sure if there's more to it than that.) Now here's a bit more in depth example that a 5 year old may be able to understand: Time as anything different than dimensional is a kind of illusion, as it is relative to where the observer is in the universe in respect to objects with mass. If I'm on earth, I'm perceiving time as being normal. If there is a second earth somewhere far away with let's say, a black hole close to it, the person on that earth will perceive time just the same as the person on earth one perceives it. But in actuality, earth number two has that large gravitational mass of a black hole close enough to it that the gravity of the black hole is affecting earth two by the bending of space time that happens with large amounts of mass that results in gravity. Since space and time are one and the same, the bending of this space via gravity is also bending time. The more bent spacetime is, the slower time goes relative to the observer. So earth two is going way slower in time relative to the viewer on earth one. Two hours could go by on earth two which could amount to ten years on earth one. Neither earth will feel a difference as each observer feels time going at a constant speed, but if each observer visits each other's planets, they will see how much time has differentiated from the beginning of the test. This doesn't mean that if we find a planet where time moves slower that we can live longer, as humans there will still have their normal age limit, it just means that relative to the other earth that has different levels of gravity acting on it time dilates drastically from each observers relative point in the universe. Also, for your second part, it is impossible to know what existed before the Big Bang, and so scientists leave it at that. Most scientists go with the fact that time and space started at the Big Bang and there was nothing before that, because there is simply no way of knowing what was before. (Unless we get into theoretical physics of there being multiple universes that this one stemmed out of, but that's all purely philosophical at this point.)", "that's the core of Einsteins work and the reason he is so important. Space/Matter and time are linked. as to the \"why\", no one can answer that, all physics can answer you there is \"how\". Why our universe is the way it is and not another way is a question for philosophy or religion. I highly recommend using the search function, as this question is asked on average every other week here.", "The speed of light in a vacuum is a constant no matter what frame of referance you use. This is the reason time slows down when you start going close to the speed of light. Its complicated math but simply if you are going 1/2 the speed of light and shine a torch forward you see that photon shoot off forward at the speed of light, but for somone stationary they too see it travel at the speed of light not speed of light + the 1/2 speed of light your traveling at. Now when light moves through space it is affected by gravity the same as everything else. If you had an infinity flat \"Earth\" and shot a photon horizontally it would fall at 9.81m/s^2 and hit the ground This is where the explination gets tricky as you have to try and visualize space time as dimensional. Which is hard. But if you have seen these images of a flat \"space-time\" grid with a planet plonked on there bending the space-time grid down and distorting it with its gravity. Now a photon travels allong the lines of this grid. Without the planet there it takes 1year to travel 1 light year easy. But when the grid bends the photon as above follows this bent space-time grid. But the distance is longer due to the planets gravity. [This is what im trying to describe]( URL_0 ) An observer in the gravity of the planet the photon will still take 1 year to travel the 1 light year, but to the outside observer due to the curve and the fact light in a vacuum always travels at the same speed, it will take longer. This means light and therefore time must have been slowed by gravity. In reality its not actually curved but thats the issue with trying to visualize time as a dimensional thing its hard to describe without a wall of math! Edit: spelling"], "text_urls": [[], [], ["https://qph.ec.quoracdn.net/main-qimg-d6269a3e09aa1583a89cb28280c6e8f0"]], "score": [68, 6, 5]}}, {"q_id": "6zer4v", "category": "Repost", "title": "How do very rich people handle their money? Do they have a bank account just like us?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dmunyn4", "dmutt49", "dmuqdiw", "dmuofar", "dmurtlg", "dmurjmm", "dmurr49", "dmuo7g2", "dmusroi", "dmutrql", "dmuvnqa"], "text": ["Someone like Bill Gates has a very small percentage of his money in the bank, the vast majority of his wealth exists as shares of Microsoft. If he needs money he can take a loan against them or sell some shares off to come up with cash It's a terrible idea to keep your wealth in a bank due to inflation so almost everyone has it invested so it grows over time. Anyone who got super rich from starting a company will have most of their wealth as ownership of that company", "Most people that we think of as \"rich\" or \"super-rich\" don't make money in the same way as most people do. Bill Gates is a great example for this. Most of his wealth isn't in cash in the bank, but in investments. In the case of Gates, his ownership stake in Microsoft is worth $12,524,470,050 (based on today's stock price and the holders information from Yahoo Finance). While some people who fall into the same income class as Gates do get a normal salary, they often choose to be paid with stock in the company they work for instead of getting cash deposited in a bank account. So the question is, how do you make money off of investments?. There are a few ways to turn investments into cash as needed: * Sell them on the open market: You could go to the person or firm that oversees your investment portfolio and ask them to sell a certain number of shares or to sell shares to gain a certain amount of money. The problem with this option is that, at the end of the day, you lose the investment. * Dividends: Companies that are profitable will often pay their investors a part of that profit. This payment is called a dividend, and they can be paid annually, semi-annually, quarterly or never depending on the company. You get a certain amount per number of shares owned. While these payments are often small (less than $1 per share), if you have many shares in a company or investment fund it can add up. * Loans: You can borrow against the value of your investments, using them as collateral. You get the cash up front and pay back the loan over time. If you fail to pay back the loan, the person who loaned you the money gets to keep what you put up as collateral. There are other issues that affect the choice of the wealthy to keep their money in assets as opposed to salaries and cash, the biggest being taxes. I'm not sure where you live, but in the United States there are many tax brackets, and not all income is taxed the same way. If you fall into the super-rich category, regular income is taxed at a very high rate. Regular income includes your salary, for example. However, when it comes to income from investments, they are taxed differently. Dividend income is taxed at a lower tax rate than paycheck income at all tax brackets in the US, so you get to keep more of your money than if you were getting a normal paycheck. There's also capital gains income. When you sell a stock on the open market, the difference between what you paid for the stock and what you sell it for is what the government in the US considers \"income\" from the stock sale, which is called a capital gain. Capital gains are also taxed less than paycheck income at all tax levels in the US. Another reason you might not want to keep money in the bank and instead have it in investments is inflation. Inflation is a reduction in the real value of your money over time due to increases in the supply of money. If you keep your money in the bank, you will gain money over time in interest but lose value over time because inflation is usually larger than the interest paid. So, if you leave money in the bank and take it out decades later, you will have more money in the end but what you can get with that money will be diminished. While not part of your original question, this state of affairs begs the question of why give such a tax break to the wealthiest people. In short, it encourages the wealthy to invest their money in stocks and other financial assets rather than hold money in cash. By investing this money in companies, both new and old, they help to provide the financial support companies need to develop new products and services and ultimately provide greater value to all of society.", "I have my money managed by a wealth management company that invests it and allows me to draw an income which doesn't decrease the value of the pot.", "I'm worth a couple million but it's all tied up in real estate, so it really doesn't feel much different than being poor except my bills are bigger.", "The good practices for personal finance applies to anyone no matter how much money they have. Keep enough money to pay the monthly bills in a bank account, have additional funds available in case of emergencies and lastly invest the rest into stock funds and bonds. If you need additional help at certain points you hire a financial adviser. The difference is really how big the numbers they deal with are. It is also easier for a rich person to hire a financial adviser on a fixed rate as the amount of money might warrant this. But that does not mean that they have a dedicated adviser. One financial adviser might handle the financial details of tens of rich people in addition to people who just want his advice in a single matter. So in general it is not as different. Adding an extra zero to a number does not make it very different to handle.", "In the UK, for example, [Coutts & Co.] ( URL_0 ) is one bank that caters to the wealthy with private banking. Dealing with large amounts of money is an area of its own (wealth management), which Coutts does too, but they also do typical bank things such as offer current (checking) accounts and issue credit cards. There is more \"hand-holding\" e.g. someone from the bank to handle any problems personally. If you have millions in \"wealth management\", the bank isn't going to freak out if you exceed a \u00a310,000 limit on a credit card, they'll just handle it by moving money around on your orders.", "Traditional wealth is usually tied up in assets, as stated here, but I am particularly curious about how people with nothing but Iiquidity (a lotto winner, for instance) would handle this.", "They have special accounts for people with high values. They give better interest, you get a private manager and they are insured for more then standard FDIC. Usually if you are wealthy you'll have several accounts for your liquid cash. That way different managers only have access to one chequeing account not your entire liquid fund.", "If you're interested, read Brooke Harrington's \"Capital Without Borders\", for how the ultra rich handle their finances.", "I see lots of comments on keeping less cash in bank and start investing, my humble suggestion is to invest only when you understand what you are investing on. It is foolish to invest just because everyone are investing and you don't understand on what it is that your investment will be doing.Small time Wealth mangers mostly just invest in the index funds, Normal guy does not have an entry to elite fund mangers. Reminds me of quote from Seinfeld \" I let my money do the work for me \" , \" your money has missed lot of work days and been sleeping \".", "In a former job, I had interactions with what is known as a \"family office\". This is a financial advisor/accountant that exists solely to deal with the wealth and investments of a single family. Technically it needs to be a member of the family, but they are able to \"partner\" with someone that is outside of the family (so if you don't have a accountant in the family, you start a business with one so you can open the family office). Additionally, you are required to prove a familial relationship within a certain number of generations (I want to say it was 10 generations must extend back to a common ancestor). Family offices receive certain exemptions - specifically from the advisers act (1940 act) So what does a a family office do? The answer is everything. From the clients I dealt with, it seems like its the perfect solution for folks that have enough money that they don't want to be bothered by anything to do with it. You have all your bills mailed direcdtly to the family office, they have your checkbook and they write all the checks. So you don't pay your cable, electric, etc, its all handled by the family office. If you wanted to buy a new car, they take care of all the financial aspects of it. They will give you all your investment opportunities, provide you with summaries, etc. Its essentially a financial concierge service for wealthy families. In exchange, they take a percentage per month/year as a fee."], "text_urls": [[], [], [], [], [], ["https://www.coutts.com/"], [], [], [], [], []], "score": [148, 127, 58, 53, 28, 8, 6, 4, 3, 3, 3]}}, {"q_id": "6zf8c9", "category": "Repost", "title": "Why were the European Colonists not ravaged by American disease unlike the Native Americans who were ravaged by European/African disease?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dmuqz2k", "dmurfdn", "dmusxox", "dmv4hjx", "dmv1xtf", "dmuvi1h", "dmv0s1u", "dmv6dh2", "dmvabm0", "dmv4zed", "dmv7l3c", "dmvaa3a", "dmvfhua", "dmvd0tk", "dmv93ud", "dmvbaq1", "dmv5kbe", "dmv10zn", "dmv4m95", "dmv6ju0", "dmv7l8v", "dmv6fsw"], "text": ["There's a great CGPGrey video on this on YouTube. Its called Americapox or something. I think it largely states that it was due to the americas not having domesticated animals which humans stay in prolonged contact with (in densely populated areas like cities), and that most dangerous diseases spread from animals to humans.", "As (can't believe I'm going to type this) /u/bunchofcunts noted stronger immune systems is the main factor, but it should be noted that syphilis went from the New World to Europe and infected many millions of Europeans.", "Along with what has already been said, indigenous peoples of the Americas had much better hygiene than Europeans, even when they had densely populated areas. This helps stop diseases from not only spreading, but forming/evolving in the first place.", "Cow, pig, horse, sheep, goat, chicken, duck, camel, pigeon. All of these animals had been domesticated in the Old World and most of them were also carriers of disease. Most of the deadly diseases come from animals, a disease does NOT want to kill its host, unless it thinks its host is a totally different animal, in which case, oops. Compared to that plethora of animal diversity in an Old World backyard, they had just the llama in the New World. Yeah, go figure. The Old World children contracted the diseases when they were small and resilient to the high temperature fevers the diseases subjected them to, making them immune from future attacks via immune system memory. When the Old World people came about, they brought the animals with them as well, as well as numerous other articles made out of those animals. We're also talking about a period of time where people in the Old World didn't bathe out of fear of catching some waterborne disease.", "Another factor is that Europe is connected to Africa and Asia, while America is isolated, so Europeans have been in contact with more diseases than native Americans in the first place.", "There were some diseases, such as syphilis that spread back to Europe. There were even some colonies that vanished due to disease. But any American disease deadly enough to ravage Europe would kill the sailors long before they made the 3+ month journey back and so the ships would never make it.", "Essentially, the European's immune system was more tried and tested with a larger assortment of diseases due to the size of the population living within close proximity for so long and the genetic diversity that came with it. There probably was some crossover with the European colonists being naive to some of the American diseases, but the Europeans had dealt with deadlier diseases in the end and had the immune systems to combat it.", "You guys may remember the Black Death hit Europe in the 1300s and killed 100 million people. Something similar could have occurred in North America. Also Vikings in Canada and USA c.1000 and no deaths.The reason why the pilgrims made it in Massachusetts is that all of the locals were dead by the time they got there. So many factors at play but not much in the historical record.", "Some have mentioned syphilis. It should be mentioned that the exact origins of syphilis are unknown, but what little evidence we have suggests it likely was brought to Europe from the New World. And to be clear, the syphilis epidemic in Europe killed _millions._ Without modern medicine, it's an extremely deadly disease. There's another disease shared during the Columbian exchange which is often overlooked: addiction. And this one went both ways. The old world brought alcohol, and the new world gave us tobacco. Addiction, of course, is a complicated disease, and I should be clear that there's thought to be no _genetic_ predisposition to alcohol or tobacco addiction, only _social._ Regardless, alcoholism is still a common killer in Native American communities today, and I don't think I need to explain the smoking epidemic to anyone.", "Europeans, due to the thousand years' advantage in domestication, had immunity to all sorts of diseases. When they came to the New World, the locals were just wiped the F out by those diseases as they had no immunity. New Worlders had much, much less exposure to animal borne pathogens in close proximity and had very little immunities that Europeans didn't already have.", "There's a book called guns germs and steel (as well as a documentary by the same name) that answers this question and similar ones in great detail", "Guns, Germs & Steel would argue it was because those on the Old World had domesticated animals. The horse, ox, cow, donkey, dog, etc. All of these lived in close proximity to humans. Over the thousands of years before contact humans in the old world gained \"immunity\" to these diseases. Due to humans arriving later in the new world (via land bridge from Siberia to Alaska) humans were generally proficient at killing large animals. The animals in the old world had developed a heavy fear of humans and \"knew\" to attack or run. Animals in the new world were rapidly driven to extinction by these \"new\" arrivals. 20,000-30,000 years later when contact occurred, the new world had fewer animal borne disease to give and had little immunity to those they were getting. On the flip side, Europeans had a really shit time with tropical diseases throughout Central/South America, Africa and Oceania. However, new evidence turns up seemingly everyday showing humans were in the Americas earlier and earlier.", "Meanwhile, while it takes a long time to kill, the Americas sent Syphilis to the old world with the french. That disease brought a new kind of madness and death to Europe, and may have triggered or exacerbated several significant wars. So it didn't ravage the landscape, but there was a good bit of trouble going the other way. Meanwhile a really good plague, were there any, would have killed off the sailors before they got home. So a tolerant crew could bring disease that the natives could be ravaged by, but a crew without the tollerance to some new disease would likely lead to a \"ghost ship\" or a simply missing ship by killing the crew \"too fast\". In truth the Europeans had a much richer palette of diseases to offer because of the constant invasion of Europe from all sides, so there were more candidates going towards the Americas. But there's a lot to be said for slow moving transport. If \"fast\" quasi-modern (1940's grade) air travel had been invented before the Atlantic had been crossed, then a nice plague or four might have indeed made the reverse journey.", "1491: New Revelations of the America's before Columbus and 1493: Uncovering the New World Columbus created, both by Charles C. Mann, discuss this topic in depth.", "There is evidence to suggest that indigenous population may have been hit quite so hard because the settlers engaged in an early form of biological warfare. For example: > Trent wrote, \"Out of our regard for them, we gave them two Blankets and an Handkerchief out of the Small Pox Hospital. I hope it will have the desired effect.\" URL_0", "Much like vaccines, they're exposed to the disease previously so they built an immunity to it.", "Additionally, I believe there was less genetic diversity amongst the American peoples based on the original migration population being relatively small I.e. A genetic bottleneck", "Really great book that includes this is ecological imperialism by Alfred Crosby. My memory thinks that the Mediterranean and Europe in general was a great place for Europeans to share diseases for thousands of years, Getting a broad resistance to disease. The native Americans simply had less of a immune system arms force built up due to so little migration to and from the America's.", "Agriculture and sewage. Agriculture made us settle down in one place, which meant our poop started piling up in one place. It was smelly and gross, so we had to find a place to put our poop, and thus we invented sewage\u2014pits and moats and stuff. It was still open air, though, so we still got exposed to the sewage. Diseases and bacteria started forming in the sewage, and constant exposure to those diseases meant we eventually became immune (after dying in droves, of course). When we sailed across the ocean blue, we took those diseases with us. Americans at the time were nomadic hunter-gatherers\u2014they roamed around, ate what they could kill or pick off of plants, and never settled down\u2014so they had neither agriculture nor sewage. So they had no diseases to bestow upon us, and no immunities to protect themselves from ours.", "I don't have a source, but I seem to remember reading that Columbus brought back syphilis which ravaged Europe.", "Long story short - European immune systems were highly developed due to all the animal shit they lived around, in densely packed cities, the shit harbours all kinds of nasty diseases and the dense cities make it easy to spread.", "Because there was no disease that could turn into a deadly plague to contract. There were a few STDs that make their way through the colonists and back to the old world, but that's about it. The major reasons being lack of large and tightly packed cities, and much contact between animals, as they had no real domesticated animals to speak off to get. So the situations in which plagues are created simply weren't present in the Americas, so there never was an Americapox."], "text_urls": [[], [], [], [], [], [], [], [], [], [], [], [], [], [], ["https://en.m.wikipedia.org/wiki/William_Trent"], [], [], [], [], [], [], []], "score": [1368, 156, 121, 103, 71, 59, 53, 13, 10, 9, 8, 7, 6, 5, 5, 4, 4, 4, 4, 3, 3, 3]}}, {"q_id": "6zfk5f", "category": "Repost", "title": "Why is B.C and A.D used to measure years in the past when only part of the world's population follows Christianity?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dmutf7z"], "text": ["Because for a long time, a huge portion of the educated elite in western europe were part of the Christian church. So the vast majority of historical records and discourse were done using that calendar. Then, since everyone was using it, it stuck, since there isn't really a good alternative. Secular folks sometimes call it BCE (before common era) and CE (common era) instead of BC/AD, but they use the same point for Year 1 so that there is no confusion between the calendar systems."], "text_urls": [[]], "score": [3]}}, {"q_id": "6zgvhj", "category": "Repost", "title": "Why do we have different electrical outlets on different continents? It seems electricity was discovered and then everyone went different ways with it. Is one setup better than another?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dmv54yu", "dmvbtdu", "dmvbpv7", "dmv4psj", "dmvnzwp", "dmweii2", "dmvuh2g"], "text": ["Before electricity, there were no fast ways of communicating across continents. When electricity was discovered within a nation, they never thought of waiting months to ask other nations about how they plug in devices. The nation just wanted to take advantage of the new invention as soon as possible! Therefore, there are so many plug standards as the first nations consulted their own engineers and scientists to make their own working plug. Once people found out there were different standards, it was too late to change since so many buildings and devices have already been converted to one type of outlet. In terms of different setups, there's two major kinds of standard voltage depending on the country: 110 Volt and 230 Volt. 110 V is the standard in North and Central Americas + western Japan. 230 V is found everywhere else. 230 Volt is more efficient power-wise but more dangerous due to the high voltage. 110 V is safer but it cannot supply as much power (ovens and refrigerators may need a separate high voltage plug). ~~Luckily, there are no plugs that can plug into both which is an easy way to burn out your device.~~ Nevermind... there are definitely plugs that can plug into both... check your adapter specifications and/or read your manual to prevent your devices from dying when using the wrong voltage! Both of these outlets supply alternating current meaning the voltage goes up and down with time. They swing at a cycle of 60 Hz (cycles per second) in countries with a 110 V standard and 50 Hz in countries with a 230 V standard. This had influence on the refresh rate of TVs since TVs fixed their refresh rates to the power frequency to prevent strobing effects that would occur if the frequencies were mismatched. Nowadays with digital content, most TVs have been standardized to display at 60 Hz refresh rate. Edit: Clarifications in the last paragraph.", "Tom Scott argued that UK plugs are superior because if the wire gets yanked the last thing to go is the Earth wire apparently making it a bit safer. I'm not so sure, I do know that if you step on an upturned UK plug you are going to come out with a long string of four letter expletives. That shit seriously hurts.", "Dunno if its technically an answer to the question but Tom Scott has a good video about the UK plug/outlet design URL_0", "Well voltage and frequency of AC supply varies by country so having different sockets is an advantage so you dont blow shit up plugging in the wrong one. Also some countries have different safety standards for there plugs. The UK has arguably the best sockets in the world but other countries didnt feel the need to develop them the same", "It is very hard to change systems once one is adopted. Ontario Canada had electric power since the 1890s, the Brock #1 power plant at Niagara Falls. But there were other private systems before that. So Ontario at one time had 2 systems, 25cyles per second and 60 cycles per second. This became so unwieldy that in 1950 they switched everything to 60 cycles. Teams of electricians went from door to door, replacing the motors in everyone's washing machines, refrigerators and other appliances. This cost a great deal of money, and inconvenience for a lot of people. Today it would be even harder and more costly.", "UK plugs are superior as far as safety is concerned - they have a fuse in the plug, pins are rectangular for best contact surface and the ground pin is longer so it connects first and disconnect last. The sockets are better too - they have individual on/off switches and shutters in them for protection, you can't reach live wire unless ground is plugged in. They are rather cumbersome and take a lot of space though. Euro plugs are a bit worse but still good, can't really reach live wire unintentionally, US ungrounded plugs are quite possibly the worst there are.", "Electricity was discovered and the tech around it was invented before communication between countries was easy. Things were still done by letter or in person so communication between neighboring countries would take days or weeks, while that between the continents could take months. So every country came up with their own standards as tech was invented/re-invented by their scientists. By the time communication was easy they already had different standards firmly established and so it was not reasonable for them to go to a uniform standard. In fact the only reason that Europe has for the most part one standard is that they had to rebuild after WWII and so took the opportunity to make things more uniform."], "text_urls": [[], [], ["https://youtu.be/UEfP1OKKz_Q"], [], [], [], []], "score": [320, 113, 67, 27, 18, 10, 4]}}, {"q_id": "6zlq41", "category": "Repost", "title": "Why do Helicopters work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dmw7ey8", "dmw8gjs", "dmw7nqs"], "text": ["The rotor is pitched. If you have ever held your hand outside of a speeding vehicle you have noticed that if you pitch your hand upwards there is a huge force generated pushing your hand up. A helicopter blade works similarly where its pitch allows it to generate lift as it rotates. The pilot can change the pitch of the blades throughout the rotation to generate different lift at different parts of the rotation to control the helicopter.", "There are two principles at work to provide lift in a helicopter rotor. The first one is that the blade is angled, so that as it \"cuts through the air\" the air is pushed downward by the face of the blade. It's like how you feel an upward sensation when you stick your hand out the window in a car and tilt your hand where your thumb is up. As your hand \"pushes\" air downward, the air pushes your hand upward in an equal force. This is Newton's Third Law in action where an action has an equal and opposite reaction. The second principle is Bernouli's Law. This states that a fluid flowing over a surface has a lower pressure the faster it flows. So with an airfoil, the top surface is longer than the bottom surface. Air flows faster over the top compared to the bottom. The faster air creates a low pressure above the air foil than the air below. This \"pressure gradient\" creates an upward force. You can see this at work if you hold a piece of paper near your mouth and blow directly over the top of the paper (but not below it). The paper will rise a little. This is because you have created a low pressure above the paper and air on the bottom unaffected side pushes the bottom of the paper. And a helicopter rotor is shaped like an airfoil.", "The rotor is not just flat blades spinning through air, they're angled like a propeller or fan. With large enough blades moving fast enough, that gives you lift. That, of course, just gets you off the ground. There's a fairly complex machinery inside the rotor that makes the blades change their angle (\"pitch\") as they rotate, giving you control over the craft."], "text_urls": [[], [], []], "score": [7, 6, 3]}}, {"q_id": "6zmd1f", "category": "Repost", "title": "Why isn't there dry human food with all the needed essentials like there is for pets?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dmwbbem", "dmwd3cu", "dmwf210", "dmwf86w"], "text": ["Because we don't want it. There is no demand for it and we prefer a varied diet. There is [soylent]( URL_0 ) which is a smoothie type thing which is essentially all you need to eat. It claims to have all the nutrients, fats, calories and whatnot a human needs to be able to survive on it alone. It exists, but it isn't exactly revolutionizing the way humans eat.", "There are actually several options, but to most people they aren't appealing. 1. Monkey chow. We're primates, it's perfectly healthful. URL_2 2. Famine relief porridge. URL_1 3. Plumpynut. A famine relief food made of peanuts and vitamins. Probably the most appealing to eat. URL_0", "The military forces use MRE's, meals ready to eat. Better than alternatives. After Katrina I helped guard piles of them at a closed drive through bank. They were free. But you could not take cases home so you could feed your dogs for the next year. There is also a special meal for inmates who are disruptive. It is nutritionally sound and resembles what they produce which they smear on the walls. So they do not seem to be doing much. In the USA MRE's will be made available quickly. In other drought regions basics such as flour, oil and rice are made available, unless the local war lord decides starving the population is in his interest..", "They do have those but they are not available in most grocery stores so are not something you can pick up just any time. These foods are sold in smaller packages and sold in hunting/fishing stores. Mostly pets understand that food is survival and nothing more.. humans want food to be fun and enjoyable."], "text_urls": [["http://soylent.com"], ["https://en.m.wikipedia.org/wiki/Plumpy%27nut", "http://www.didionmilling.com/dry-corn-mill/blended-products/", "https://www.amazon.com/ZuPreem-Primate-Diet-Dry-20/dp/B0002ARMVS"], [], []], "score": [28, 8, 7, 3]}}, {"q_id": "6zmosr", "category": "Repost", "title": "How hushing came to be the sound we use when we want people to be quiet.", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dmwehl1", "dmwmrb3", "dmwpaw3", "dmwohhw", "dmwnrf8", "dmwq8ab", "dmwne1r", "dmwmd14", "dmwpyyv", "dmwmpo7", "dmwp8es"], "text": ["I always wondered about the same thing and quite recently I discovered that the hushing sound is the most common sound you can make with your mouth to calm down a newborn baby: they naturally calm down when they hear vibrations and white noises. I wouldn't be surprised it just came out from this: a lot of p\u00e8arents who are used to hush to silence and calm their babies and simply go on doing that when they grow up, and, bang, you create the international conventional sound for silencing. ^there ^is ^nothing ^scientific ^about ^this, ^only ^personal ^observation", "Going \"shhhhhh\" makes broadband (white) noise. It's (1) very audible, even when done quietly, and (2) clearly distinct from voices. I think we made a good choice assigning it as the \"be quiet\" sound. I bet it doesn't work very well nearby waterfalls or steam valves.", "Unrelated, but me and my friends in middle school used to shhhhh the school cafeteria to a lull. It was kind of a fun social experiment. Pissed off the teachers for some reason.", "When I was in France people would pour a cup of water from their balcony while we were being noisy walking home from the club. This happened on a few occasions. I was told by locals that this wasn't to try and hit us but to tell us to shut the fuck up. Could \"Hush\" and \"Shhh\" be linked to flowing water and the calming noise it makes?", "The Shhhh noise is calming to babies. It's similar to the noises in the womb. So we say Shhhh to sooth a crying/noisy baby. Then the idea that Shhh is a noise that indicates people should be quiet is embedded from birth. And we do that because our parents did it. The cycle continues.", "I was told by a nurse in the birthing center that the \"husssh\" sound mimics the sound a mothers \"white-noise\" that is generated by her digestive tract and circulation system and then transmitted through the amniotic fluid to the childs ear. I don't know how true this is... but it works. I think it is probably something similar or it could just be a \"sensory overload\" for the child and a distraction from whatever is bothering them. Mom: Shhhhhhhhhh Baby:\"Woah!... what's all this information coming from my ears into my brain... wait... I HAVE ears!?... when was someone going to tell me about this...and why am I thinking in English... I can't even talk or comprehend language yet... now... what was I whining about again?\" From there it just becomes a universal human communication pattern to \"hush\" regardless of age.", "One of the reasons it might be so common and effective is that the white noise generated by shushing might sound similar to the flow of blood through arteries which an infant would have experienced while gestating.", "Seems like if you want someone to be quiet, and you want to let them know that using a sound, you'd choose the quietest sound possible. I mean, shouting \"HEY BE QUIET!!!\" sort of defeats the purpose if quiet is what you want. Can you think of any quieter sound you could make than shhh?", "It might just be that \"Shhhhh!\" is the quickest way to get people to stop whatever it is they're doing and pay attention because primate brains have a strong hard-wired response to a snake's \"hiss\". For instance, it's thought that cats hiss and spit and lay their ears flat in order to sound/look more like a snake since so many animals have a strong fear response to them and perhaps without quite realizing why \"hush\" worked so well, humans started using it as a \"Stop! Be quiet/pay attention/danger!\"", "Harsh hushing is really abrupt. It works on animals too. It shuts everyone up/breaks their focus", "We make 2 basic sounds, \"hiss\" and \"grunt\", with different mouth shapes. Probably since the first of what you would call intelligent homosapien, if u needed someone around you to be quiet, you would choose the quieter \"hiss\" sound."], "text_urls": [[], [], [], [], [], [], [], [], [], [], []], "score": [599, 193, 68, 37, 22, 22, 8, 8, 8, 6, 3]}}, {"q_id": "6znk6o", "category": "Repost", "title": "Why do daily multivitamins have more nutritional value than we need?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dmwlosg"], "text": ["Because were unable to soak up all of it. Like trying to clean up soda with a dollar store sponge some will always be left on the floor"], "text_urls": [[]], "score": [3]}}, {"q_id": "6zodhl", "category": "Repost", "title": "Manifest Destiny", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dmwrd8f"], "text": ["It was the belief by some Americans in the 19th century that Americans were destined and obligated to expand, settle, and develop western part of the US all the way to the coast."], "text_urls": [[]], "score": [4]}}, {"q_id": "6zorxk", "category": "Repost", "title": "while on call, my phone is able to remove music so that the other person can only hear my voice. How does it do this?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dmwvfsc", "dmwvloq"], "text": ["This is the beauty of the *noise canceling microphone.* A second microphone farther from your mouth detects what sounds are coming from the room rather than from your mouth, and these are subtracted from the signal. Yarr! Yer not alone in askin', and kind strangers have explained: 1. [ELI5: How does the iPhone 5 noise cancelling microphone work? ]( URL_0 ) 1. [ELI5: While on a phone call, how does the other end not hear the video I am playing on my phone? ]( URL_1 )", "With one or a few extra microphones. The idea is pretty simple, but there is a lot of thought out into making it reliable and useful; If you place an extra microphone on the backside of the phone, it will catch all the ambient noise around you. But it will not hear your voice very well. And the regular microphone will hear you voice AND all the ambient noice. So, in theory all you have to do is to remove all the noise that is heard by the extra microphone, and all that is left should be your voice. For extra accuracy, add not one but TWO extra microphones. And place them differently so that they catch different noice each."], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/17npnn/eli5_how_does_the_iphone_5_noise_cancelling/", "https://www.reddit.com/r/explainlikeimfive/comments/2b2eq7/eli5_while_on_a_phone_call_how_does_the_other_end/"], []], "score": [9, 6]}}, {"q_id": "6zpl0t", "category": "Repost", "title": "Why does the same note sound different between instruments?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dmx2ca6"], "text": ["The sound from a physical instrument is pretty far from a single-frequency tone; there's a whole medley of higher overlapping frequencies created by the shape and material of the object that are collectively called \"[timbre]( URL_0 ).\" The main note that you hear is just the loudest and lowest frequency."], "text_urls": [["https://en.wikipedia.org/wiki/Timbre"]], "score": [6]}}, {"q_id": "6zpro3", "category": "Repost", "title": "Why does time seem to go by faster as you get older?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dmx3nm8"], "text": ["I want to imagine it is as if the more time you experience the less a single moment is. so if you are alive for ten seconds, a single second is 10% of your life, after 10 years, one year still seems like a long time, but after 50 years, a single year now is so much less, and that might be why it seems like that way."], "text_urls": [[]], "score": [6]}}, {"q_id": "6zq7ad", "category": "Repost", "title": "Why are there identifiers for single and married women (ms. and mrs.) but not for men?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dmx73es", "dmxm5ho", "dmxca6t", "dmxwkv4", "dmxu575", "dmxvnb2"], "text": ["There are for men. The honorific term for an unmarried male is \"master\". But that honorific fell out of use in the late 1800s early 1900s. But it has remained in use is some regions and specific places such as with some very proper butler schools (think Alfred with Bruce Wayne).", "So many BS answers in this thread, apparently from folks fresh out of Gender Studies 101 at your local State U. Misogyny isn't applicable here. Fact is, there are titles for both married (Mister/Mr.) and unmarried (Master) men. The latter is still used, though not commonly (just as Miss isn't super common these days--the professional world often uses \"Ms.\", pronounced \"Mizz,\" for all women regardless of marital status).", "In less enlightened times, a woman's prospects were determined largely by whom she married. From the time she came of age, she and her family's priority would be to find the best husband they could. Since her desirability was largely based on attractiveness and her ability to bear children, she faced a ticking clock, and every year she remained unwed lowered her stock as marrying material. Conversely, a man's desirability was based on his accomplishments and wealth...he could land a better wife if we waited until he had more of both. Facing less of a biological timetable, men were under less pressure to marry immediately, and instead were encouraged to make their fortune in the world first. For these reasons, it was much more important for a woman to advertise her marital status, by way of a title, than for a man. She wanted as many eligible bachelors as possible to know it, in hopes of attracting the attention of the best. Also, since in polite society, the woman did not initiate romantic contact, it didn't really matter if she knew a man's marital status because she wasn't supposed to act on that information. Many women reject the sexism inherent in these outmoded customs, and choose to uses the title Ms., whether they are married or not.", "Several comments on this thread have claimed \"Master\" is (or was) an honorific title for unmarried men. This is completely untrue. Master has only been used as a polite form of address for boys under 16 or 18, when they are too young to be called \"Mister\" without it sounding a little strange. This convention was traditionally to do with when one became a \"man\" and entered into society as such, and nothing to do with marital status. Unmarried adult men were never referred to as \"Master\". And when it comes to Bruce Wayne, mentioned in one comment - the whole point is that Alfred has known him since he was a small boy and in a sense still sees him as such, so continues to call him by the title you'd call a boy. It's an affectionate in the way that calling someone \"son\" or \"young man\" would be for an older person.", "Pretty sure it's Master for unmarried men and Mister for married men. It's only really used in official forms and stuff though.", "We do men in the uk when you don't know their marital status are called master, it's the reason I'm never getting married :)"], "text_urls": [[], [], [], [], [], []], "score": [148, 29, 25, 9, 5, 3]}}, {"q_id": "6zs7x0", "category": "Repost", "title": "How does a record play all the different notes and sounds of a song?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dmxocqx"], "text": ["Your ear only hears in one dimension: at any given instant in time it senses the pressure of the air against your eardrum. When an instrument plays a note that produces a rapidly changing pressure--it goes from higher-than-ambient pressure to lower-than-ambient pressure hundreds of times per second. Your ear interprets that rapidly changing pressure as the sound of that instrument. When two instruments play different notes at the same time they both produce rapidly changing pressure waves. What you hear is literally just those two waves added to one another. Your brain then does some amazing processing to be able to identify that it's two different things, to tell what they are, and so on. What this means is that to encode any number of instruments playing simultaneously you just need a single waveform and it'll be as good as your ear can tell. This is accomplished by having a single groove that moves back and forth as the needle traces it. The wiggling of the needle is amplified to go to the speaker. If the groove is precise enough, the amplification is clean enough, etc, then the sound will be indistinguishable from the original to your ear (in practice things aren't perfect, which is a way you can tell it's a recording and not live). The shortcoming of this is that most people don't have *an* ear. They have two. The above description works for older mono records, but people have two ears and want to hear things accordingly: you need two signals at any given time. You could accomplish this with two grooves, but that would be make it hard to get the needle positioned right. You could also set up the groove to wiggle not just left and right, but also up and down, like [this]( URL_1 ). That approach gets you pretty far, but it makes it so that a mono record player will just get one track. You also have a hard time making the up-and-down track balanced with the left-and-right track, since they're different motions and may be interpreted differently on one record player or another. To improve on that design you rotate the whole thing 45 degrees like [this]( URL_0 ). This setup allows a stereo record player to get two equal tracks off of a single groove while allowing a mono record player to get a single track that's influenced equally by both of the stereo tracks."], "text_urls": [["http://i.imgur.com/289QsY2.gif", "https://i.makeagif.com/media/5-12-2015/qdLj8D.gif"]], "score": [4]}}, {"q_id": "6zt3gn", "category": "Repost", "title": "Why does a dead phone have to charge before booting, while a dead laptop will turn on right away?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dmxv6t0", "dmxu8ns", "dmxwl7r"], "text": ["Your laptop is designed to run from 2 power sources: 1) battery 2) direct from AC power adapter Your phone can only run from the battery, and therefore always needs to wait for the battery to reach a minimum charge.", "Minimum voltage requirements if I remember correctly your laptops max drain won't exceed what it can get from the wall your phone will on bootup however. Also as a data safety mechanism most laptops won't let you go below 5% true battery.", "I have a PC hybrid tablet that does exhibit the same behaviour: it has to charge for a certain time before it will turn on at all. It's by design."], "text_urls": [[], [], []], "score": [13, 6, 3]}}, {"q_id": "6ztewf", "category": "Repost", "title": "How do mountain goats climb up seemingly completely straight surfaces?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dmxxmil", "dmxwcbv", "dmy0xfe", "dmxwglf", "dmy11ez", "dmxyzc7", "dmxwdd7", "dmy0mcz", "dmy0h36", "dmy3d4s"], "text": ["Great balance and precise movements. Not unlike how it's kind of miraculous that humans are bipedal. Walking on 2 feet on uneven terrain and up stairs is pretty impressive too.", "Because it's indeed only seemingly completely straight, a different angle: URL_0 That picture is probably cut in that strange way only to hide what reveals it's not a vertical wall.", "[because they crave that mineral. ]( URL_0 ) On a more serious note, they have hooves that have evolved to be able to climb these almost straight surfaces and I'd assume a lot more muscles than we do as humans. Also probably a combination of speed + muscles + agility -- > climbing up mountains Edit: \"designed\" - > evolved", "To start with their hoofs are very sharp and their legs are thin. So even if there is a slippery piece of rock sticking half an inch out from the cliff they can put their weight on it without slipping. They also have a lot of balance and control over their movements so they can balance on those narrow ledges. And of course it does help to have four legs. So just like a rock climber can climb seemingly straight smooth surfaces a goat can use a lot of the exact same footholds to climb up.", "On top of every one else's mostly correct responses - Practice! Goats climb on and jump off of everything they can from birth. They have a real urge to get up on stuff and as babies they are terrible at it with lots of tumbles but they get better and better with time. r/goatparkour", "How often do goats fall to their deaths when climbing up weird and vertical walls and cliff faces?", "Goat hooves have a more rubbery texture than horse or cow etc hooves. They have grippy toes.. Plus, they're super agile/adventurous. Goats get themselves in all kinds of weird places.", "Rigid, hard-rubber style hooves, and a lot of free food for scavengers at the bottoms of cliffs.", "The have weird hoofs it's like a horses on the outside but a dogs soft in the middle giving them lots of grip.", "\"Since this pic was posted a few months ago, I can tell you the consensus then was that the photo is tilted and cropped to exaggerate the angle of the wall. Check out the angle of the trees in the foreground and background. \" \"Yep, this is the actual angle.\" URL_1 URL_0"], "text_urls": [[], ["https://imgur.com/a/5g2zX"], ["https://m.imgur.com/t/mineral/uwt3i6c"], [], [], [], [], [], [], ["https://www.reddit.com/r/NatureIsFuckingLit/comments/6zr5u5/goats_climbing_a_brick_wall_are_xpost_2sweatypalms/dmxi631", "https://imgur.com/a/5g2zX"]], "score": [2058, 584, 244, 142, 107, 62, 43, 18, 17, 4]}}, {"q_id": "6zvptk", "category": "Repost", "title": "what exactly does \"Promise to pay\" on a bank note means? Who exactly makes the promise to pay the barer of the bank note, and what does this pay is actually supposed to be paid in?", "title_urls": {"url": []}, "selftext": "How about like currency that doesn't have \"promise to pay\" written on it, e.g. Chinese RMB?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dmyd8ed"], "text": ["On the vast majority of banknotes, it doesn't mean much of anything anymore. Historically, banknotes were redeemable (at times practically, at other times only theoretically) for a specific amount of precious metal (usually gold). But that hasn't been true for most currency in decades. For example, the Bank of England has this to say about the phrase on their banknotes: > The words \"I promise to pay the bearer on demand the sum of five [ten/twenty/fifty] pounds\" date from long ago when our notes represented deposits of gold. At that time, a member of the public could exchange one of our banknotes for gold to the same value. For example, a \u00a35 note could be exchanged for five gold coins, called sovereigns. But the value of the pound has not been linked to gold for many years, so the meaning of the promise to pay has changed. Exchange into gold is no longer possible and Bank of England notes can only be exchanged for other Bank of England notes of the same face value. Public trust in the pound is now maintained by the operation of monetary policy, the objective of which is price stability."], "text_urls": [[]], "score": [7]}}, {"q_id": "6zx86f", "category": "Repost", "title": "Why does the human eye can see just the colors blue,green and red, while you need yellow,blue and magenta to mix all colors if you're painting?", "title_urls": {"url": []}, "selftext": "In my biology class I learned that the human only reacts to blue-violett,green and red rays. But in my art class I learned that you or a printer for example needs to mix magenta,blue, and yellow together to get every other color. So why humans can see all color and printers can print all colors?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dmyq7sa", "dmywluk"], "text": ["We see red green and blue, but since pigments are about removing light from white light, it uses different colored pigments which each selectively *remove* red, green, or blue from the light. Removing red light gives us cyan (which you refer to as 'blue' above). Removing green gives us magenta. Removing blue gives us yellow. Since you are dealing with printing, four color process will also use black because it is difficult to get pure blacks by mixing real-life pigments together.", "Read through the comments and while they are correct, it's not really the answer to your question. The difference between light colors and paint colors is the way they mix. Light (additive color mixing): Light gets brighter when added to each other. Think of 3 spot lights. The light gets brighter if the spots have the same target. Combining a red spot, a green spot and a blue spot, produces \"perfectly white light\" (Just in theory, as it is fairly hard to produce light of only one exact color) Paint (subtractive color mixing): With paint it's the other way around. There are the 3 cleanest colors, or basic colors, Cyan, Magenta and Yellow. As opposed to Red, Green, and Blue when working with light. Everytime you mix a basic color with another, it gets darker. Adding yellow to cyan, makes it green. Adding magenta makes it brown. Where I am from, we call this 'breaking the color'. Adding the basic colors in same parts, would theoretically produce black. Source: Worked as an offset printer and now working as a graphic designer. Had to use these principles everyday for the last 7 years. Edit: Forgot the answer to your last question: Our eyes are far from seeing all colors and our printers are far from being able to print all colors For the eyes: We see in RGB. So everything you have ever seen, is just that. Everything we can see. What we call colors, are just the wavelengths our eyes can detect. Infra-red cameras basically convert invisible light (infra red) to visible light (RGB on the screen of the camera) For printers: Printers have a really limited amount of colors they can produce, compared to RGB. The problem being that a screen shines, producing nicely saturated and bright colors, while paper doesn't. There are specialized systems to increase the color range of a printer, but even then, it's no match for RGB."], "text_urls": [[], []], "score": [33, 6]}}, {"q_id": "70020g", "category": "Repost", "title": "What exactly happens when a body part \"falls asleep\"?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dmzcxpj"], "text": ["You have some sort of pressure applied on an area of that body part, and have caused blood flow to slow. As it slows down, and that part of you isn't given enough oxygen to work correctly. Your nerves then begin to react, telling you to remove whatever pressure is on your arm, and bring the bloodflow back to normal."], "text_urls": [[]], "score": [3]}}, {"q_id": "700n3g", "category": "Repost", "title": "Can you explain the fundamentals of Bitcoin and other cryptocurrencies?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dmzl6fj"], "text": ["i recently found this video explaining the topic in great detail but relatively easy to follow: URL_0 maybe not exactly ELI**5** but still..."], "text_urls": [["https://www.youtube.com/watch?v=bBC-nXj3Ng4"]], "score": [4]}}, {"q_id": "700u7m", "category": "Repost", "title": "How do manufacturers of vehicles make car keys that are unique such that not 1 car key is identical to the other?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dmzivga", "dmzms06", "dmzk3zz", "dmzj12f"], "text": ["Certainly with normal keys, it's more than possible that there do exist keys that will open more than one lock, but the whole security of a lock and key is that you don't know that. Or put another way, if you were to find a random key at the side of the path one day and pick it up, would that make you any more likely, in the grand scheme of things, to be able to get into the house it came from? No, because you don't know which house that is. Could be any one of millions of keyholes. Cars are the same. Odds are with the number of cars in the world, there are certainly keys that are duplicated somewhere, but how do you know where and what cars? You have no way of knowing.", "Certified Registered Locksmith of nearly 10 years here. Newer cars are getting better about this. Manufacturers are moving away from physical keys, to remotes and push to start systems. This is decreasing the likelihood that a random person will be able to accidentally access your car. For older models that utilized pin tumblers that utilized cuts on the edge of the key as opposed to the face, it was common for manufacturers to only use a fraction of the key bitting for different locks on the car. The ignition would use the most, while the glove compartment might only use three, and the doors use five of a different combination, and the trunk will use a different combination of four or five as well. This worked because many keys had 8 cut positions. Ford, for example had 8 positions, with 4 different depths. This leads to nearly 65,000 different theoretical key combinations. Not all 65,000 could be used to to physical restrictions of the keys. It might not be possible for a deep cut next to a shallow cut on some manufacturers, or some manufacturers have specific rules about their key bittings. With all that being said, car manufacturers do their best to make sure that you are the only person near you with a key to your car. But sometimes you may get an anomaly. But the likelihood of that happening is very small. Plus the transponder in the key is unique and must be programmed into the car. Tldr: it is possible for cars to have keys, other than those with the car, to have identical cuts. However, vehicle manufacturers do what they can to limit this and electronic security is helping", "Once upon a time I did accidentally open a car of the exact same make, model and color with the key to our family's car. It was in the parking lot of a mall and they were parked just a few cars away from ours. This was two decades ago before car remotes became popular. Nowadays many manufacturers use laser cut keys which gives a pattern unique to each car, nearly eliminating the possibility of producing identical keys.", "The trick is that they don't. They just need to make them unique enough that most keys do not fit. So there will be less accidents with people taking the wrong car and it is not convenient for car thieves to carry around a full set of keys. But that means that you might just need to make less then hundred unique keys for all the cars. Modern cars with radio chips in the key does have an added level of security as these often have a lot more unique patterns then physical keys."], "text_urls": [[], [], [], []], "score": [14, 6, 5, 5]}}, {"q_id": "7015ck", "category": "Repost", "title": "Choas Theory.", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dmzkuvg"], "text": ["A system is \"chaotic\" if it is strongly dependent upon its initial conditions. Chaos theory is the branch of math that deals with those sort of systems. Say you're throwing a baseball in the air and are calculating where it lands. You know the initial speed and trajectory, and can determine where the ball will land. There are other factors, like windspeed, temperature, etc., but they don't change the outcome much. A little bit of wind will move the ball's final position a little bit, and you can pretty much ignore those if all you want to know is about where the ball will go. But let's consider a classic example of a chaotic system: weather. Weather is totally deterministic: if you know everything about how the weather is now, you could determine exactly how the weather will be later. However, unlike the baseball being thrown, a very small change to the initial weather conditions can dramatically change how the weather plays out over time. If there's just a tiny breeze present, that can be the difference between whether or not it rains in a week, or something like that. We've got weather stations all over the world, but we don't know the exact conditions in between those stations. Because these little unknowns can cause amplified results later on, weather is inherently hard to predict. One of the prime uses of supercomputers is to predict weather, because it's so hard. And this is why weather forecasts are less reliable the further forward you forecast: beyond a week or so, we really have trouble predicting what will happen. When hurricanes form, we can model where we generally think it will go, but because it's a chaotic system, we never actually know, because where it goes exactly is dependent upon all these little initial conditions that are hard to measure. Human lives are chaotic: the most seemingly-unimportant events in your early life can have profound influences on how it ends up. My entire career, for example, occurred because of a single afternoon I stayed late in physics class and my teacher happened to have his laptop out and it was running Linux. I owe my girlfriend to the fact she happened to get off early on a day I was late catching a bus. So... chaos theory is the math that deals with these sort of systems."], "text_urls": [[]], "score": [5]}}, {"q_id": "701iz0", "category": "Repost", "title": "Why does your stomach \u201cgrowl\u201d when you haven\u2019t eaten?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dmzmkbc", "dmzmlk4"], "text": ["Your stomach always growls, but when you have food in your belly you can't hear it as much, when it is empty you can hear it a lot more due to it being empty", "If I remember correctly, it's cause your stomach is always making those noises but if you don't have food in your belly there's nothing to block the noise. Sounds silly now that I write it out though"], "text_urls": [[], []], "score": [4, 4]}}, {"q_id": "701muw", "category": "Repost", "title": "What purpose do the wheels that don't touch the ground on a trailer serve?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dmzngmb", "dmzndgs"], "text": ["They *can* touch the ground: the driver can lower them as needed. It saves fuel to have less wheels on the ground, so when a truck isn't carrying enough weight to warrant it, they're lifted up and unused. When it's heavy enough to need them, they're lowered to help support the weight.", "When the trailer is empty it doesn't need to distribute load on multiple wheels. But driving around wears the tires down so the driver can lift one pair off the ground to save them. Not all trailers have this feature."], "text_urls": [[], []], "score": [6, 4]}}, {"q_id": "701nmq", "category": "Repost", "title": "How do things go viral on the internet?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dmznuqk"], "text": ["It's a combination of luck, interesting content, and connections. If your content is really good, on the right platform with a bit of luck, people will see it and it'll grow organically. If your content is meh but you have connections like a popular person with 1M instagram followers, then it can go viral simply by that person sharing it."], "text_urls": [[]], "score": [3]}}, {"q_id": "7023va", "category": "Repost", "title": "Why do so many U.S. states have capitals in small and rather insignificant cities?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dmzqua8"], "text": ["Yo ho ho! Yer not alone in askin', and kind strangers have explained that the choices were usually made on geography, or on some historic significance of the place: 1. [ELI5: How come state capitals in the US are usually not the state's largest or most important cities? ]( URL_5 ) 1. [ELI5: Why are so many State capitals in the US not the biggest city? ]( URL_4 ) 1. [ELI5: How is the capital city of a country/state decided? ]( URL_3 ) 1. [ELI5: Why are capital cities often not the largest cities/financial centre in many countries or vice-versa? ]( URL_0 ) 1. [How come state capitals in the US are rarely the largest city of the state? ]( URL_6 ) 1. [ELI5: How are capital cities chosen for a state/province/country? ]( URL_1 ) 1. [ELI5: Why isn't the most well-known city in a U.S. state considered it's capital. ]( URL_2 )"], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/22zpda/eli5_why_are_capital_cities_often_not_the_largest/", "https://www.reddit.com/r/explainlikeimfive/comments/2oll8q/eli5_how_are_capital_cities_chosen_for_a/", "https://www.reddit.com/r/explainlikeimfive/comments/18zagv/eli5_why_isnt_the_most_wellknown_city_in_a_us/", "https://www.reddit.com/r/explainlikeimfive/comments/1kdhiq/eli5_how_is_the_capital_city_of_a_countrystate/", "https://www.reddit.com/r/explainlikeimfive/comments/6hekmn/eli5_why_are_so_many_state_capitals_in_the_us_not/", "https://www.reddit.com/r/explainlikeimfive/comments/5wersu/eli5_how_come_state_capitals_in_the_us_are/", "https://www.reddit.com/r/NoStupidQuestions/comments/2dz0fu/how_come_state_capitals_in_the_us_are_rarely_the/"]], "score": [3]}}, {"q_id": "702rvf", "category": "Repost", "title": "Why is the advent of the number 0 a big deal in mathematical history?", "title_urls": {"url": []}, "selftext": "Based on a recent post, I saw that it is apparently a \"big deal\" that mathematicians started using the number zero. To me it seems that even during a hunter gatherer society someone would have asked how many blueberries another dude picked, and that guy would say 0, because he didn't find any...", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dmzyepg", "dn0bea5", "dn06eva", "dmzxwzg", "dmzxi0j"], "text": ["> To me it seems that even during a hunter gatherer society someone would have asked how many blueberries another dude picked, and that guy would say 0, because he didn't find any... That's kinda it. They didn't say they had zero of something. They said they didn't have that something. There's a subtle difference there, where you treat the zero of something as categorically different situation than some positive number of something. Ancient Greeks debated this, and they ended up concluding pretty much this. And for the most part, to them, this was just a philosophical question. It really didn't have any real effect to their lives if zero was considered a number or not. The great things happened when you got 0 introduced into a positional number system(which Greeks didn't have), like the one we use, where 10 for example has one of tens, and zero of ones. People had used positional number systems before, but without number zero, and as a result, they could not tell apart numbers like 1,000 and 100 because there was just blank space signifying none of that position. Basically, it's difficult to appreciate just how revolutionary the number system we now take for granted really is, and how powerful it is in its ability to represent all numbers using just a couple of different symbols.", "Zero and negative numbers were a big deal because they gave us our modern picture of the rules of arithmetic, and we no longer had to make awkward exceptions. If you don't believe in anything other than positive numbers, a - b doesn't always exist (it only exists when b < a), and a - b + c might not exist even though a + c - b does. By contrast, in our modern mindset you can do any subtraction, the order doesn't matter, you can make a number stay the same by \"adding zero\", and you can undo addition or subtraction using number pairs that sum to 0, which is where negative numbers come in. Only using positive numbers had all kinds of subtle consequences. I'll discuss one area as an example. If you've ever heard of \"imaginary numbers\" (square roots of negative ones), you may wonder why mathematicians were so unconvinced of them at first that they gave them that name. The reason is that even negative numbers were contested back then. There was a time when we didn't have a single simple theory of quadratic equations, because we felt there were four kinds of them: compare x^2 = 5x + 6 (one solution: 6), x^2 + 6 = 5x (solutions 2 & 3), x^2 + 5x = 6 (one solution: 1), x^2 + 5x + 6 = 0 (no solutions). If you argue I've missed negative roots, that's my point: people didn't accept them back then. If you argue these are all of the form x^2 + ax + b = 0, possibly with a or b negative, that's my other point: people who didn't accept negative numbers couldn't talk about it like that. The axioms of modern arithmetic can be summarised as \"numbers form [a field]( URL_0 )\". Look at how many of those rules can't be true with positive numbers alone; look how much trouble it creates for the notion of subtracting, or of \"solving\" x + b = a. Now \"field\" is one of many terms in mathematics you don't learn in school, but they're the bread and butter of the modern subject. And what a lot of them have in common is that they have rules like, \"There's an object with these relations to every other object\" (e.g. 0 + x = x + 0 = x, for each x there's a y with x + y = y + x = 0). In a way, zero lay the groundwork for these kinds of ideas, by which we can generalise the rules of ordinary numbers to very different-looking structures that, say, are also a field.", "Zero is not the same as nothing, just as symbolically being able to represent and manipulate \"7\" is different than being able to hold up 7 fingers. Zero was a breakthrough because it allowed us to shift from additive number systems to placed based ones. Additive systems, like Roman numerals, consisted of a bunch of symbols you added together or occasionally subtracted: MCMLXXVIII = 1000 + 1000 - 100 + 50 + 10 + 10 + 5 + 1 + 1 +1 This worked ok, but it was really cumbersome to do math with, especially multiplication and division. 1978 = 1000 + 900 + 70 + 8 Is a lot easier to deal with. But there is a problem, without a zero, you have a hard time representing certain numbers. MCMVIII = 1000 + 1000 - 100 + 5 + 1 + 1 +1 Which is: 1000 + 900 + 8 = ? 198? 19X8? Zero is needed as a place holder to properly express 1908. It doesn't just mean nothing, it is part of the entire system.", "He certainly wouldn't say zero berries if there was no word for zero. He might express the concept in a different way, however. Having an actual name for zero and the viewpoint that it's just as real as 1, 2, 3, etc. enables more complex math. It allows the shift from very concrete viewpoints (I have three pigs), to thinking hmm, I can create an equation which represents how many pigs I have at any given time, starting with time zero being five years ago. Then you move to looking at that equation and seeing the slope at a certain time can be meaningful, especially if that slope might be zero. I have a lot of pigs, but the slope is zero...I'm no longer increasing my herd.", "Introducing zero as a number and not just the concept of nothing meant we were moving passed math just being used to calculate how many bushels of wheat you had to give me for 3 lambs. Math became more abstract which lead to a huge number of advancements."], "text_urls": [[], ["https://en.wikipedia.org/wiki/Field_%28mathematics%29#Classic_definition"], [], [], []], "score": [50, 24, 13, 5, 3]}}, {"q_id": "7034u0", "category": "Repost", "title": "Why is smiling a positive sign in humans whereas in other species showing teeth is considered aggressive?", "title_urls": {"url": []}, "selftext": "Understandably showing teeth is aggressive behaviour in some animals but why do we show them to signal happiness, amicability etc?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dn02j4t", "dmzznf7"], "text": ["\"I never smile. Smiling is a sign of submission in primates. So whenever I see someone smiling, all I can think of is a chimpanzee begging for it's life.\" -Dwight Schrute", "Other animals tend to attack with their teeth. Humans attack with our hands or legs. So, baring our teeth isn't a sign of aggression like it is with other animals."], "text_urls": [[], []], "score": [9, 8]}}, {"q_id": "703hjp", "category": "Repost", "title": "Why does gasoline reflect so many colours when you see it in puddles or near water?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dn02kib"], "text": ["You're in luck, this question has already been asked and answered: URL_0"], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/369u45/eli5_why_gasoline_puddles_are_all_rainbowy/"]], "score": [4]}}, {"q_id": "704bzo", "category": "Repost", "title": "What would happen if a human was microwaved for one minute?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dn09zbv"], "text": ["They'd die a very painful death. Microwaves agitate the water molecules in food to make them vibrate essentially and heat up. That would be happening to ever water molecule in your body, it would boil you alive from the inside out."], "text_urls": [[]], "score": [13]}}, {"q_id": "704nbm", "category": "Repost", "title": "What is actually \"cracking\" when you crack your knuckles?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dn0e0t3", "dn0d6lr"], "text": ["Each joint is surrounded by a capsule, which is filled with the synovial fluid. Its job is to exchange gases between the blood and the cartilage, which covers the ends of the bones and reduces friction. When you crak your knuckles you stretch out this casule and increase the volume, therefore lowering pressure. This causes some of the gases of the fluid to \"undisolve\" since it the soluability is reduced. (This is also why soda starts fizzing more when you open it for the first time: the pressure inside drops and the carbon-dioxide undisolves.) So what you're hearing is the formation of bubbles. And since it takes a while for everything to return to normal, you can't crack the same joint in quick succession. Hope this helps.", "I could easily be mistaken, but since there are no comments ill give my understanding. Nothing is physically cracking. It's gasses being released."], "text_urls": [[], []], "score": [9, 4]}}, {"q_id": "705le9", "category": "Repost", "title": "Why Do Phones Take pictures That Look Further Away Then They Actually are?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dn0ld2h"], "text": ["Phones use a wide-angle lens which has a different field of view than our eyes, and do not represent distances between objects the same way. This is necessary because without a wide angle lens, selfies would be impossible and you'd need to take several steps back from anything you were trying to shoot, making it useless for indoor use."], "text_urls": [[]], "score": [21]}}, {"q_id": "705zeh", "category": "Repost", "title": "Back in the 90s there were a few vehicles that came out with 4 wheel steering. Why didn't this become a thing?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dn0panx"], "text": ["4-wheel steering is still around. They were a bit more accessible during the Japan techo-fest heydays of the late 80s. Where you can have 4WS Honda Prelude, etc. Unfortunately, the system is complex and the advantages aren't enough to justify the expanse. They are costly to produce and costly to maintain. Look up Honda forums and there would be various threads about how to disable and bypass 4WS for older models. But there is a return to 4WS on high end exoticas. With Porsche GT3 having such a system. Where people are willing to pay hundreds of thousands of dollars for the ultimate performance, such system make sense again."], "text_urls": [[]], "score": [3]}}, {"q_id": "706s6a", "category": "Repost", "title": "How do those special glasses that colourblind people wear allow them to see colours?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dn0v5on"], "text": ["They don't. What they do is *block* some of the colors that they see. Which seems counteintuitive, but these glasses only work on people who have a specific type of colorblindness where they have cone cells that are messed up, and are partially triggered by the wrong color. Your eyes have cells that can detect red, blue, and green light. But what they really do is detect a *range* of light in the general areas of red, blue, and green. Some types of colorblindness cause the colors that trigger those cells to overlap too much with the red-detecting and green-detecting cells. So some wavelengths of red light trigger both the red-detecting and green-detecting cells, and some wavelengths of green light trigger both the red-detecting and green-detecting cells. What these glasses do is block out the wavelengths of light in that overlap, so that green object are less likely to trigger the red-detecting cells, and red objects are less likely to trigger the green-detecting cells. This allows the person to better distinguish between red and green in real-world situations, but it doesn't cause them to see colors that they can't actually see."], "text_urls": [[]], "score": [3]}}, {"q_id": "707kov", "category": "Repost", "title": "Why does the setting on most all fans go 'OFF-3-2-1' rather than ascending from the lowest speed?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dn12fd9"], "text": ["This was asked a little bit ago. The answer was that the \"1\" setting may not be powerful enough to start up the motor. Starting at \"3\" juices it right up."], "text_urls": [[]], "score": [5]}}, {"q_id": "707vq8", "category": "Repost", "title": "Why do people look so distinctly different in photographs than they do in real life?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dn14aya", "dn14dw0", "dn16kuz", "dn14ufa"], "text": ["Yer not alone in askin', and kind strangers have explained: 1. [ELI5:Why do people look better in person then in pictures? ]( URL_8 ) 1. [ELI5: Why do some people look unattractive in photos, but look attractive when in person? ]( URL_0 ) 1. [ELI5: Why do I look so much better in the mirror than I do in pictures? ]( URL_6 ) 1. [Why do I look handsome on the mirror, but ugly in photos? ]( URL_5 ) 1. [ELI5 Why do we look different in a mirror and in a photograph? ]( URL_1 ) 1. [ELI5: Why do I look different(or better) in mirrors than I do in pictures or videos? ]( URL_7 ) 1. [ELI5: Why do we look different in reflections and in photos? ]( URL_4 ) 1. [ELI5: Why do I look different in pictures of me and what I see in the mirror? ]( URL_3 ) 1. [ELI5: Why does one look ugly on camera, but handsome in the mirror? ]( URL_9 ) 1. [ELI5: Why do I look pretty in the mirror but horrible in photos? What makes someone Photogenic? ]( URL_2 ) 1. [ELI5: is there a reason I like how I look in a mirror but hate pictures and videos of myself? ]( URL_10 )", "The lens, the camera, f-stop, focal distance, exposure, the ISO sensitivity. The contrast with the backdrop. The distance from the camera. Some facial features enlarged when close enough. Photogenicity: some people have a gift for maintaining just the right facial muscle tone.", "Whenever someone asks this question I almost never see the actual answer get posted. The primary reason is that we have stereo optic vision. Because we have two eyes when we look at a three dimensional object we are seeing it from two slightly different angles. Our brain combines these images. When you're staring at a flat two dimensional photograph you don't get the same effect.", "So you're telling me I don't look that good in person? :("], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/4epshp/eli5_why_do_some_people_look_unattractive_in/", "https://www.reddit.com/r/explainlikeimfive/comments/5zqh9z/eli5_why_do_we_look_different_in_a_mirror_and_in/", "https://www.reddit.com/r/explainlikeimfive/comments/22gqxw/eli5_why_do_i_look_pretty_in_the_mirror_but/", "https://www.reddit.com/r/explainlikeimfive/comments/2zscs5/eli5_why_do_i_look_different_in_pictures_of_me/", "https://www.reddit.com/r/explainlikeimfive/comments/5rz2ri/eli5_why_do_we_look_different_in_reflections_and/", "https://www.reddit.com/r/NoStupidQuestions/comments/528abw/why_do_i_look_handsome_on_the_mirror_but_ugly_in/", "https://www.reddit.com/r/explainlikeimfive/comments/1u0x8o/eli5_why_do_i_look_so_much_better_in_the_mirror/", "https://www.reddit.com/r/explainlikeimfive/comments/1m63k8/eli5_why_do_i_look_differentor_better_in_mirrors/", "https://www.reddit.com/r/explainlikeimfive/comments/2l02l6/eli5why_do_people_look_better_in_person_then_in/", "https://www.reddit.com/r/explainlikeimfive/comments/3peui2/eli5_why_does_one_look_ugly_on_camera_but/", "https://www.reddit.com/r/explainlikeimfive/comments/6uu4mi/eli5_is_there_a_reason_i_like_how_i_look_in_a/"], [], [], []], "score": [29, 17, 8, 6]}}, {"q_id": "708p2j", "category": "Repost", "title": "How Do Anti-Color Blindness Glasses Work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dn19zr7"], "text": ["First of all, they don't work for everyone. (Only for people with red-green colour blindness) Second, they do not let someone see a colour they can't see. So how DO they work? They don't add colour, the actually remove some colours. They filter out the section of wavelength where red and green kinda overlap, which makes it easier to distinguish between the two. People with this type of colour blindness still have some use of red and green cone cells but they are causing an excess of overlap of signals, so if something is red *or* green they basically look the same, mushy orangy colour. Here's an image showing kinda-sorta how they work URL_0 tldr anything red is made REALLY RED and anything green is made REALLY GREEN and anything in the middle is filtered out so red and green are seen as contrasting hues"], "text_urls": [["http://www.spiritearthawakening.com/wp-content/uploads/2016/11/rsz_1untitled.png"]], "score": [5]}}, {"q_id": "708yd8", "category": "Repost", "title": "How are teenagers getting addicted to the Blue Whale app and even killing themselves when it seems to have no actual rewards?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dn1bsxy"], "text": ["Because they're teenagers? I'm not being snarky - teenagers go through phases, trying to figure out who they are in a complex world, seeking more independence, re-negotiating their relationships with the people around them: parents, teachers, peers, the opposite sex. I'm not an expert on \"Blue Whale\", but my understanding is that that game provides a narrative, an apparently logical progression that promises to help them with personal problems. The \"narrative\" theory is important - a narrative gives structure and continuity, things that a confused teenager may feel to be missing from his or her life."], "text_urls": [[]], "score": [3]}}, {"q_id": "709mwi", "category": "Repost", "title": "Mobile phone radiation and health, is this something we should worry about? Why/why not ?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dn1fuf1"], "text": ["No, it's not something you need to worry about. People hear the word radiation and they immediately think about atomic bombs. The reality is that there are two kinds of radiation: ionizing and non-ionizing. Ionizing radiation is the scary kind from atomic bombs and nuclear reactors. Ionizing radiation leaves a trail of irradiated material in its wake and this can cause serious, long-lasting damage to living cells. Non-ionizing radiation includes things like visible light and the radio waves from your cell phone. This type of radiation passes through an object and doesn't cause any long-term damage. Enough of it could cause immediate damage just like enough light can cause a fire. But, it doesn't irradiate the material."], "text_urls": [[]], "score": [5]}}, {"q_id": "70al9d", "category": "Repost", "title": "If sharks have to keep moving to breathe, what happens when they get tired?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dn1opcs", "dn1otqv"], "text": ["Similar ELI5: * URL_0 punkinholler posted: For one thing, not all sharks have to keep swimming to continue \"breathing\". Nurse sharks, for example, can and do sit on the bottom all day with no trouble. As for the sharks that do swim all the time, a quick Google search suggests that there's no clear answer on whether or not they sleep at all or how to even define \"sleep\" for them. However, dolphins have similar breathing troubles as sharks because breathing is always under conscious control for them (i.e. they only breathe when they think about it) so they'd drown if they fell asleep like humans do. Since dolphins are so much easier to study than sharks (sharks can't be trained to cooperate with researchers), we know that dolphins get around that problem by only sleeping with half of their brain at a time. At such times they have only one eye open, they tend to hang out at the surface, and they can and do move around sluggishly. I know you didn't ask about dolphins, but since there's no answer for the shark question, I figured I'd throw it in as lagniappe. Source: URL_1", "Sharks have a unique swimming pattern. Imagine them as a plane. They burn energy taking off, get to top speed and altitude, then cut the engines, gliding down under minimal power, only kicking the on engines just before they hit the ground and starting the cycle over again. Sharks swim hard to surface, and can rest as they glide down to depth. This keeps them moving with minimal energy, so they have plenty in reserve when it comes to murdering time. If they run out of energy to burn to the surface, they die, because nature is metal."], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/5ubuey/eli5_how_do_sharks_survive_when_they_dont_sleep/", "https://www.scientificamerican.com/article/sleeping-with-half-a-brain/"], []], "score": [7, 3]}}, {"q_id": "70bppr", "category": "Repost", "title": "How did Facebook know my shower drain was clogged?", "title_urls": {"url": []}, "selftext": "I have 4 daughters, so I go through a few [Hair Snares]( URL_0 ) a year. As it gets used, I cut it down with a pair of scissors, because the little barbs get worn out. A few weeks ago I noticed the snare was short and worn, so on my lunch break I went to Home Depot and picked one up, paying with my Bank of America Visa debit card. I didn't mention it to anyone via text, phone, social media, anything (because it's not really a thing you need to tell anyone - \"holy shit remember Sean from high school? He has to clear a hair clog every damn day!\"). I also didn't search for it online, because I knew exactly what I was going to buy. Later that day I signed into Facebook and all my ads were for plumbers, Roto Rooter, Drano, and the very Zip-It brand hair snare I bought. The only logical explanation is that some weird combo of Visa, Home Depot, the Apple free Wifi at Home Depot (I checked Instagram while walking), Bank of America sold my info to Facebook. In pretty much hours. **ELI5: how the heck did my purchase get turned into Facebook ads when I didn't text or search or publicly declare my need for clean drains?**", "selftext_urls": {"url": ["http://www.homedepot.com/p/Zip-It-Bath-and-Sink-Hair-Snare-BC00400/100665735"]}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dn2hh4z"], "text": ["A series of things are happening. Home Depot is collecting data on you when you swipe your card. They know who you are from your credit card and they know you bought your hair thingy so they know you have clogged drains. They can then sell that information to marketers. Those marketers have already gone out to companies that clear drains and said if you pay us, we will target your drain clearing ads to people we know have clogged drains. Now the marketer goes to Facebook and says we want to place drain cleaning ads to this person because we know he has a clogged drain. All of this set up is done beforehand. So the guy behind you that bought potting soil gets logged by Home Depot as doing some gardening, who then tells that to the marketer who has contracted fertilizer and garden tool companies, and the marketer tells Facebook to send that guy ads for gardening supplies."], "text_urls": [[]], "score": [7]}}, {"q_id": "70bsga", "category": "Repost", "title": "Why does the reverse gear sound so much different in cars?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dn1z419", "dn21bqa"], "text": ["Because it isn't used much it is a straight cut gear to save cost. The other gears are helical cut. The helical gears are quieter because they mesh more gradually rather than flat surfaces against each other", "In a manual transmission the reverse gear is \"spur cut\", basically straight teeth like you think a gear would have. The rest are helical cut, the teeth spiral around the gear instead of being straight. Helical cut gears are both stronger and quieter because there is more surface making contact. Helical gears are always \"meshed\", touching, but they are not always locked to the shaft they turn. When you select a gear the synchronizer makes both shafts turn at the same speed so the dog teeth and collar can lock the gear to the shaft. When you go to reverse you are changing the direction of rotation of the output shaft, you cannot use a helical/synchro setup to do this (the input shaft would always be locked tight) so you have to use a spur cut gear that can be meshed for reverse and then disengaged to go forward again. These issues can and have been solved, but it is very expensive. In automatics the sound is different because you are using a gear ratio that is not normally available to the forward gears. It is pretty much between first and second gear, ratio wise, so think gear 1.5."], "text_urls": [[], []], "score": [9, 4]}}, {"q_id": "70gzhz", "category": "Repost", "title": "How does a song that's sung in English or any other language get translated to a different language?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dn339hn"], "text": ["Interesting question. Generally, songs use a lot of phrases and sayings that don't make sense when directly translated, and if they do, they rarely line up with the syllables and rhyme scheme. So instead, they basically write a new song with roughly the same theme, that makes sense in the language. For instance, *La Mer*, by Charles Trenet, has lyrics in French with the following direct translation: > The sea, > We see dancing along the shores of clear bays, > Shimmers with silver > The sea > Changing shimmers > Under the rain > The sea > With the summer sky > Mix up her white horses > With the angels so pure > The infinite azure shepherdess > Sea > > Sea > By the ponds > Those big wet reeds > See > Those white birds > And those rusty houses > The sea > Has cradled them > Along the shores of clear bays > And with a love song > The sea > Has rocked my heart for life But if you actually [listen to the song]( URL_1 ), you'll recognize the tune as Bobby Darin's [Beyond the Sea]( URL_0 ). The original song was just a nice little snapshot of a beautiful sea on a cloudy day, while the American \"version\" pays homage to the sea, but abandons the original meaning entirely. Another example, possibly more in line with what you were asking, can be seen in the lyrics to, \"Liber\u00e9e, Delivr\u00e9e,\" (\"Liberated, Delivered\") which is the French version of \"Let it Go,\" from *Frozen*. > Winter settles gently into the night > It's the snow's turn to be queen > My place will always be > in the kingdom of solitude > The wind howling in me no longer thinks of tomorrow > It's much too strong > I've fought in vain > Hide your powers, don't speak of them > Pay attention, the secret will survive > No hesitation, no torments > of sentiments > > Liberated, Delivered > I'll never lie again > Liberated, Delivered > It's decided, I'm leaving > I've left my childhood back in the summer > Lost in the winter > The cold is for me > The price of liberty > When we look down from above > Everything seems so small > The sadness, the anguish, and the fear > Left me long ago > > I want to see what I can do > with this mysterious magic > The good, the bad, I say 'oh well' > Oh well! > > Liberated, Delivered > The stars extend their arms to me > Liberated, Delivered > No, I won't cry > Here I am! > Yes, here I am! > Lost in the winter > > My power came from the heavens and invades the space > My soul expresses itself by drawing and sculpting in the ice > and my thoughts are flowers of the frozen crystals > > I'm never going back > The past is in the past! > Liberated, Delivered > Henceforth, nothing can stop me > Liberated, Delivered > No more perfect princess > Here I am > Like how I've always dreamed! > Lost in the winter > > The cold is for me, the price of liberty. You can see that this version has roughly the same themes, but they're spoken about very differently. Because it was a Disney song, it needed to fit into the context of the movie, so they didn't have full autonomy to change lyrics around like witg *La Mer*, and you can also find some nuanced differences in these lyrics and the original. Elsa actually seems more confident and actualized in the French lyrics than she does in the English ones (which are essentially about her losing control over suppressing her powers and accepting it, rather than truly embracing them). Hope this answers your question"], "text_urls": [["https://youtu.be/5bRAtV-jgoQ", "https://youtu.be/PXQh9jTwwoA"]], "score": [8]}}, {"q_id": "70hjs1", "category": "Repost", "title": "Why can you only check your credit score in the us without being penalized once per year?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dn36o7j", "dn35nxe"], "text": ["> Why can you only check your credit score in the us without being penalized once per year? You can't even check your credit score once a year. What you can check is your credit *report*, which is a list of all accounts and billing activity tied to your identity, so you can look for things like fraud and identity theft. > How come if it is your credit score it doesn't work like an online bank account where you can log in and check it whenever you want. Because your credit score is proprietary data created by the credit reporting agencies as a product that they sell to other companies to categorize how risky it is to lend you money. It's not something that is particularly useful for you to know in most situations, and allowing people to access it freely would result in people reverse-engineering the algorithm behind it, which would make it useless since people would start being able to game the system.", "You can if you pay for it, and checking your own credit never hurts your credit. You get one free full report a year because there is a law that requires it. The credit agencies are businesses, so they charge for their services."], "text_urls": [[], []], "score": [8, 3]}}, {"q_id": "70hypr", "category": "Repost", "title": "The UK education system and the order it goes in.", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dn39zok"], "text": ["Basic order in england is (Preschool / nursery school / kindergarten) Primary: 4-11 y/o Secondary: 11-16 y/o [finish by taking GCSEs] Sixth form college: 16-18 y/o [finish by taking A-levels] (Uni) You do fewer, more specialised a-levels than GCSEs: the latter you have to cover the spectrum of compulsory stuff, the former you dont. So you have to do GCSE maths for example but at a-level if you hate STEM and want to do dance, french and history then fine. But bear in mind there is no \"uk education system\" really. Scotland i know is different to England, dont know about NI, Wales i think is legally mostly the same as England but even within England there is loads of variation. Some people (esp in private education) have prep schools and middle schools. Some people's sixth form is part of their secondary, other people go to a separate institution. Some people do alternative qualifications - international baccalaureat, vocational ones (stuff like welding) instead of academic alevels, etc. Some places call them high schools, grammar schools, academy, village college, etc instead of secondary school. Sometimes this actually means something is different for the student; sometimes it is a technicality of funding or governance but little difference to the student; sometimes it's basically just a historic name but it's no different in practice to any other secondary."], "text_urls": [[]], "score": [4]}}, {"q_id": "70i9ck", "category": "Repost", "title": "Why do we get eye crust when we wake up in the morning?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dn3d588", "dn3cv31", "dn3erv6"], "text": ["Finally when I can answer, so if you look closely at the corner of your eye where your eye boogers form there's a small hole that hole is called a punctum it is directly connected to your sinuses that's why if you pinch your nose and close your mouth and forced air up from your lungs air will come out of your eyes so as you sleep secretions from your sinus flow through this punctum and out your eyes so quite literally your eye boogers are boogers", "I was told that it's mucus, skin cells, dust and other crap that your eyes are trying to get rid of so they will not be damaged.", "Crusty eyes is caused by oils, dead skin, miscues, and other stuff that comes from or around your eye. Usually the eyes are good at dispersing the gunk or only leave a little bit in the morning. If you have pink eye the crustiness gets much worse"], "text_urls": [[], [], []], "score": [111, 20, 3]}}, {"q_id": "70ihla", "category": "Repost", "title": "Human babies are a luxury?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dn3d69p"], "text": ["Our large brains mean we have to be expelled from the body before we grow too large to fit through the birth canal, so as a result we have to do a lot of our growing outside the body. Our brains are also the reason why we have and can use weapons to prevent being eaten by a lion."], "text_urls": [[]], "score": [7]}}, {"q_id": "70iieo", "category": "Repost", "title": "How are concrete bridges built in deep water?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dn3efzs", "dn3ixzo", "dn3ei7o"], "text": ["Concrete doesn't dry to harden, it cures, which means it can be poured into a form underwater and still harden.", "I'm a construction engineer, and I actually studied a bit of this in school! If there is bedrock, they may try and drill down to the bedrock and have the foundation rest on that. When concrete cures, it is a chemical reaction, so it isn't \"drying out\". It can cure underwater. A lot of bridge foundations are done that way. If there is no bedrock, it's common to use a pier. Piers are long columns that are driven into the ground. You can think of them like giant nails that are hammered into the earth. They can be made of concrete, steel, or wood (think of a boardwalk near the ocean). There is friction between the sides of the pier and the earth, which is what prevents them from sinking.", "The water in Florida isn't that deep. It's just sand, you can use normal footings. Sometimes you just drive a precast piling into the sand. Or build a coffer dam if you want to pour concrete. I think I've seen coffer dams made from large pipe sections dropped end-downward to the bottom. Any time the water is deep, you'll have a suspension bridge or a floating bridge."], "text_urls": [[], [], []], "score": [14, 7, 5]}}, {"q_id": "70iimp", "category": "Repost", "title": "If the main goal of our brain is survival, why does it let get depressed and in some cases commit suicide?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dn3v6ud", "dn3dfag", "dn3ztzs", "dn3dhgq", "dn3xu66", "dn3lvin", "dn3fqne", "dn3rjrn", "dn3est0", "dn3j7vz", "dn3edif", "dn3ksho", "dn3u9r4", "dn3zx2w", "dn3ear6", "dn4ackt", "dn4aqgt", "dn3vqkq", "dn3pqya", "dn3ykyx", "dn3h6qn", "dn41e0j", "dn4aymx", "dn4ad1n", "dn474y7", "dn3x17h", "dn3sjvl", "dn3xetl", "dn3ox18", "dn43a43", "dn4apz1", "dn3se48", "dn4dw27"], "text": ["Psychologist and Suicide Counsellor. If you see the brain as a tool for solving problems then suicide is adaptive. Problems solved, pain ended. I do not condone suicide - there is usually another option... But reading through this thread, maybe it's society that contributes to depression and suicide by shaming people who are down and out with labels like 'maladaptive'. No one is an island. I prefer to see thoughts of suicide as the last recourse of a mind trying to cope with a huge problem. People usually feel a bit better about their issues (and I think less likely to kill themselves) when they hear that. Edit: Grammar", "Our bodies don't have \"goals\" per se, they are how they are because it has worked \"well enough\". Of course our bodies tend toward efficiency because it tends to survive harsh times better, but the fact is that occasional depression and suicide are malfunctions at an acceptable level for the continuation and proliferation of the species. Evolutionarily speaking the individual is irrelevant.", "I'm not a scientist, but I have battled anxiety disorder in the past and learned enough about anxiety and depression to give an educated answer on this! It all has to do with human nature and it's relationship with environment. I know that sounds vague, but stick with me... Humans, as hunters and gathereres, had a drive for survival that was constant--running from dangerous animals, hunting animals, gathering food, procreating, etc. A lot of natural stimulation. But, as civilization is now, many people have easy access to food, aren't running from anything and have rooted stimulus in things like television, music, sex, social environments, etc. With complex society comes a lot of social constructs that are abstract ... made up, to put it lightly. You have to have a car, a wife, a job, a kid, money, happiness exterior to your desk job, friends, a successful favorite football team, a cool hobby, etc. We don't actually HAVE to have these things, but in a life where we aren't in immediate danger or starving our brains begin using these arbitrary social constructs and reacting to them chemically. With anxiety disorder, the central issue is that sufferers enter the \"fight or flight\" response for things like...idk...not getting a text from a crush after texting them, or misinterpreting something your boss said, or not having money. Our body reacts the same way it would if you were backed into a corner by a bear, but there's no actual danger. Depression is the other edge of the sword. We can get overstimulated too fast because of the complexity of our society. Remember your first roller coaster ride? Think about all the emotions you felt beforehand, right? Now think about how you would feel if you rode one each day for your entire life. Eventually the feelings of anxiousness subside. It's kind of like how birthdays were awesome as a kid, but eventually they're just...bleh. We live lifestyles where repetition and routine can leave us surrounded in a world that we find, eventually, not interesting at all. This is why people with seemingly no \"major issues\" end up depressed. Also, we put a lot of worth in other things, so that when we lose them it's depressing. Example: at 13 my Dad took my Xbox away. I was actually depressed for weeks. When we get to more complex things like breakups, or losing a job, or a friend, or financial trouble, we lose our sense of self worth. That's not right...we are all very lucky to live in the time and place we do, so ironic it is that we get jaded and self deprecating so easily. And social media is a category in itself. We are operating in a daily lifestyle where there's constant need for recognition and we are constantly comparing ourselves to others. TL;DR -- our fight or flight instincts are not compatible in a modern lifestyle, so our brains literally recalibrate to our surroundings -- often with unhealthy results", "The main goal of life is to reproduce, not to survive. Survival is a byproduct. Mental disorders are disorders, as in, not the norm. Anomalies happen.", "Suicide is more like a solution to a problem than self destruction per se. I used to suicidal....so I can tell you it becomes something we fanatsize about. Something we look forward to. In a way.....I guess we don't see it as death.....just as a solution. We go over solutions in our head and that is the one the solution that surely \"works.\" And if we get sad we think \"well....I know suicide will work for sure....\" Our survival instincts kick in when we go to kill ourselves. I tried twice in my life.....and both times scared the shit out of me. Every person who has killed themselves regretted the moment it was too late....remember that. I tried to kill myself at 16....and again at 22.... I'm 27 now....and had I died I would have been missing out on some of the most wonderful things life can offer. I'm not a psychologist.....but I figure I would chime in with my personal experience anyway.", "Depression is a physical illness of the brain which causes adverse effects such as suicidality and isolating behavior. It is not normal and just like when any other organ is afflicted with a malady we should treat it as though it is malfunctioning. The terrifying and confusing thing about the brain is that it controls our personality which we like to think is separate from the body but is very much connected to our physical state.", "The answer's in your question. It's because the brain isn't working right. That's practically the definition of mental illness, which is an underlying cause of a lot of suicides.", "I suffer from depression since five years and asked me this myself. Note that depression is a bunch of symptoms and is different for everyone. E.g. some people cry for days, since can't cry at all, some eat like a whale some loose weight. However most mental illness has external influences, though we found some Genetics. See those illnesses as reactions of the brain to it's surroundings. So, assume your life is shit. Like so bad you are constantly sad. After a while your brain can't deal with that anymore. It reduces all emotional reactions, good and bad. That's depression, a loss of emotional response. One point about biology: the more you use a strain of thought the faster it gets (mathematics, language etc.). If you constantly use your \"I'm shit\"-thoughts you get really good/fast at thinking you are shit Assume you are in life threatening situations: rape or military operations. People often suffer PTSD from that. And some of ptsds symptoms are - an extreme level of awarness your surroundings: my ex-bf was working in kindergarden and was able to know every childs position at every time. - split yourself from your own experience: many describe it as watching someone else in their bodies. - uncomfortable to human touch, loss of trust etc.", "IIRC, the goal of evolution is survival of the species, not of the individual. If an individual person is in a situation where they feel that they are not contributing to this end, they may feel inclined to eliminate themselves in order to preserve resources for the rest of their society. I don't know if this is accurate or not, but it seemed to make sense at the time that I heard it.", "It's believed that depression is a first world disease. If you're concerned with surviving, you don't get depressed. There have been studies of indigenous people, and depression doesn't show up in them, and when asked about suicide, one group laughed, asking, \"why would anyone kill himself?\"", "A brain is like any other organ - it will malfunction. But our knowledge of the brain is very little as compared to other parts of the body.", "Your brain is not designed to function in a modern civilized society. Artificial light, lack of sleep, lack of exercise, improper diet, none of these were problems for humans pre-civilization. Survival is only a goal from an evolutionary perspective, it's not something your body is purposefully doing. All the things that keep you alive are pre-programmed.", "Gad Saad said something about this once (iirc) and basically revolves around the fact that depression stems from not being able to contribute to the group. From an evolutionary standpoint the groups survival is more important than the individual so an individual that cannot contribute is effectly a drain on their species. This in turn makes their brain trigger a depression so they recuse themselves and possibly terminate themselves to eliminate the drain on the group. It's brutal, but a valid theory. Another theory is that depression stems from inflammation of the body so when you become injured or diseased your body will make you become depressed. This will make you more prone remove yourself from the group to reduce the risk of transferring the disease or endangering anybody else until you are healed. The problem is, if your body stay inflamed for any reason chronically (diet, lack of exercise, etc...) Then you never return back to normal and the depression deepens. Its all speculation because the human mind is one complex motherfucker.", "As someone else mentioned, the goal of evolution is not survival of an individual but survival of the species. In other words, reproduction of viable offspring. But to add to that, it may be better not to think of it as a \"goal\" at all. It's more of a natural consequence. Why does wood float on water? It's not because wood *wants* to float on water. It just happens because of the materials' densities and the laws of physics. Similarly, it's not that every species *wants* to reproduce and perpetuate its genes (I mean, we have other reasons to want to engage in reproductive acts, but there's no built-in motivator as a species... you know what I mean). However, the species that are around today are the ones that were more likely to reproduce. Because the ones who didn't like reproducing just died out a long time ago. Wood floating on water. Edit: put another way: We don't reproduce because we like sex. We like sex because our ancestors were the ones who reproduced the most, and in a group of animals where some happen to like sex and some don't (much like some people happen to like blue and others don't), those who liked sex would have reproduced more. It's very circular and I'm not explaining it very well, but the point is, a person's brain does not *want* to survive. It's just a collection of genes and characteristics that exist because all its ancestors happened to survive *long enough to have kids* and that's it. Any traits that don't affect surviving long enough to have kids will have no effect on evolution, and sometimes they combine in weird ways to produce glitches.", "Lack of meaning in a post-(post?)- modern world. Maybe there is no need to survive, no need to forage , to hunt, to gather , to build , to journey. We weren't meant to sit inside at desks for 8+ hours a day. We are animals. And consciousness is our tragedy. But what do I know", "We evolved with the concept of \"pain.\" Pain is something that tells your brain something is wrong, that something is happening to your body which needs to stop or or will kill you. It's suffering. Our ancestors (and nearly all animals) suffered throughout evolution as a means of survival. Brain: \"That hurts? Don't do it.\" The problem is that this feeling of suffering is often misinterpreted by the brain. Like a child that won't take medicine because it tastes bad, the brain *thinks* it's making the right decision because the terrible taste is clearly poison or inedible. And when the body survives despite this thinking, the brain believes it did something right. **The brain knows it's supposed to suffer.** Now, after millions of years of evolution, our society gets to a point where a huge part of the population has no reason to suffer. We have shelter, food, medicine, love, entertainment- everything humanity has struggled to attain throughout its entire history. It's all here. There's nothing that makes us suffer like our ancestors did. Predators, disease, hunger, sexual gratification, natural elements- all under control. But the brain knows you're supposed to suffer. And nothing outside of your body is causing it. So the brain *makes* you suffer. It interprets things to make you suffer. You aren't suffering, so those people don't actually care about you. You aren't in pain, so you don't deserve the life you have. Why are you happy? You should feel bad- you haven't felt bad enough to earn your existence. You're a piece of shit. You're so worthless. Depression. Finally. Pain. Good. But your life does one of three things- it gets worse, and your brain was right. You don't deserve it. After all, all these bad things are happening. (And they may not even be bad things, but your brain convinces you they are because it needs something to go wrong). So you still feel horrible because your brain was right- you don't deserve this and you're finally suffering. Or your life stays the same. Nothing changes. Your brain was right- you haven't done anything to deserve this. So it continues to search for suffering. Or your life gets better. But you didn't suffer enough for it, did you? You didn't actually earn this, or the life before it. We need real suffering. Or. An escape. A healthy diet and exercise can help you deal with it. But that's work. And work isn't suffering. Video games, or a movie. Temporary but effective. You distract yourself. No suffering. Drugs. Drugs can block out that part of your brain. Alcohol, heroin, antidepressants. Drugs, drugs, drugs. The good ones can help your brain realize it's okay to not suffer. The bad ones can lead to actual suffering, which is what your brain wanted the whole time. Your addiction forms. Finally, suffering. An addiction to the drugs- an addiction to the suffering. And sometimes it's not enough. Your brain becomes so exhausted, so tired, so full of pain that isn't caused by anything but itself that it just wants everything to stop. No more suffering, no more pain- nothing. It has to stop. Suicide. There's nothing actually wrong with you- your brain is just trying to cope with the suffering it's never experienced. It thinks it's helping. But sometimes you need someone else's help. National Suicide Prevention Hotline: 1-800-273-8255", "First time poster, very long time lurker. But for once, I know a thing or two about the subject and I'll try to participate in this great community. The brain is like any other organ of our system, it has a role and has to fulfill certain tasks. Like the rest, it has evolved to do these in the most adaptative way up to date. Today, we understand quite a lot of what it does but to say the ultimate goal is survival, we don't know really. The psyche, the mind, is something else. It's who we are, what we remember (and what we forget), what we experienced, what we think. Our brain does not think, we are. Of course, there is a very close intricacy between the two, as brain activities are often started by a thought. But the brain didn't create the thought. Psychic life is built on losses and separations, and our capacity to integrate them goes with our capacity to create. You could say that's how we grow up, how we change. Some authors talk about the \"depressive capacity\" as something invaluable and depression would be the failure of it. Depression occures for someone when an inanimate state becomes the only way for him/her to stay alive. Something (not necessarily someone) has died and to keep it, one identifies as the tomb. This impossible grief neutralises the depressive capacity. Antidepressants have a cortical action that erase some of the pain. This action on the brain alone will not solve the depression, but it will restores a minimal psychic well-being that allows the creative capacity to come back. I tried to stay as ELI5 as I could, also please excuse my English as it's not my native language. Edit: typos", "Strictly speaking, I don't think the brain has survival as a goal. It has developed several mechanisms to avoid/seek relief from things which are painful. It just so happens that things we identify as painful also tend to be things which are actually hazardous to us. This gives the appearance of a goal. I'm guessing it seems so universal because things that didn't have the ability to feel pain and react had no motivation to keep themselves away from potential danger, so their genetic configuration had a lower likelihood of being inherited. It may be that suicide is just an extension of that desire to avoid pain or seek relief from it. Since we can understand that pain can last beyond the immediate circumstances, and that frequently the things we do to relieve it will only provide temporary relief at best, it can look like there is no end to the pain. This doesn't stop you from wanting relief, so your mind keeps working until it arrives at a solution.", "First of all, not the brains goal is survival, evolutions goal is survival till reproduction. We are able to produce kids at the age of 12. Most people died before 20 historically and the rest made losts of kids, so our numbers grow, evolutionary we are winning. Evolution doesn't really care about anything else. We did select for stuff ourselfs as humans over the time we lived, but we can't really select for brain chemistry that might go awry at some point in the future, because it hasn't happened yet. People get depressed at different ages. Also we are not in a natural enviroment. Everything we created is artificial. It might be that we are actually doing something wrong as society. In nature you have to work everyday and get immediate gratification. You search for food, you find food, you eat food, you are happy. You find a suitable mate, she accepts you you are happy. In modern society everything is a lot more abstract, in many decades and still in some countries today, if you weren't able to do something that other people really need and appreciate, you have a miserable existence (especially when you compare yourself to others). Often you really can't do much about that.", "I feel as though living in today's advanced society lends itself to depression and suicides in individuals who might have otherwise made a happy hunter-gatherer human or something. It's not the environment which our brain adapted to survive in. Of course depression before civilization may have been a positive adaptation, but in our new societal environment, depression festers and doesn't help the individual hardly at all. In other words, our brains do what they think they're supposed to in order to survive, and usually what the brain does is the right thing even in our new modern environment. However, modern unfamiliar territory seems incompatible with the brain not just for the obvious case of suicides, but also for the general happiness among people. This is what happens when we take a system optimized to do one thing and tell it to do another. Given the rate of pharmacological and neuroscience advances, (and since I can't see us changing the status quo to conflict less with what our brains evolved to encounter anytime soon), I'd wager we will have drugs effective enough on the brain to eradicate most issues of severe depression and suicide by 2100. A synthetic adaptation if you will, simulating hundreds of thousands of years of evolution all in a few pills.", "While somewhat contentious as it's hard to scientifically prove, meme theory may play a role in this as well. From an evolutionary standpoint, you're right - it makes no sense to have things like depression or suicide. It also doesn't make any sense to evolve a brain our size from a physical standpoint. So we must consider the possible ideas a brain like ours harbors, memes (the technical term for such ideas, not a joke). Basically, it looks like suicide and depression are not developmental side effects of evolution directly. Evolution only caused us to have a big brain and comprehension as to allow for more memes. Such memes indirectly happen to cause more existence thought, in addition to everything else that makes humans just so darn good at surviving.", "It's not normal, it's your brain fucking up. There's a reason why depression is considered a disorder/illness. Your brain is just an organ so depression is just like a heart attack or kidney failure in that sense. It's just not working the way it's supposed to. Weather it's due to life circumstances or genetic predispositions, depression can be treated in many cases if the individual seeks help", "the brain simply is what it is. The statement that the main goal of the brain is survival is an assumption. An organism is simply a biological machine that maintains its form and propagates it's form. It's a physical object that has no agenda and just so happened to reproduce itself because reproduction is a positive feedback loop and a series of occurrences caused evolution. A body's main goal isn't to survive. It just so happens to have mechanisms that facilitate preservation of it's form. it's an object. Emotions are not perfect survival mechanisms in every sense of the word. They are merely mechanisms. For example fear causes us to run and preserve our lives, but we can also become frozen in fear, which is a counter productive behavior. We can allow ourselves to get pricked by a needle full of medicine can't we? Organisms are not as utterly bound to their survival instincts as your paradigms suggest.", "Our brains were not designed. The do not have a \"survival goal\" set in advance. Instead, we have evolved somewhat haphazardly over thousands of millennia in ways that depended on the particular set of pressures at the time. Evolution is a process of (unguided) trade-off and compromise. On average, the human that have survived until now must have some advantage over the ones that did not. That's tautological. I'm just speculating from here on but maybe the flexibility of a problem solving brain (which is evolutionarily beneficial) just has an unavoidable side-effect that it can (at the extremes) descend into fatal obsessiveness; or maybe slightly more resources were diverted from brain activity to immune systems, or muscle growth or bone strength or blood oxygen; or maybe (as /u/doppelwurzel said [in this comment]( URL_1 )), the habits of a person with depressive tendencies lead to a net gain because it led to more focused problem analysis. The problem is that our brains have a complex set of feedback signals with mind-bogglingly (heh) intricate chemical-receptor interactions. If the balance of the chemicals tips a little too far, it can switch the decision making process from \"super-obsessive but effective problem analysis\" to a crisis of \"[analysis paralysis]( URL_0 )\".", "Ooh! I can answer this for once. Firstly, we must understand the role that sadness plays in human lives and society. It is a biological response to something bad happening in our lives. It is a way our body tells us, hey, this isn't good for you. It allows you to take a step back and reconsider certain aspects of your life. It also plays a role in \"social signalling\". Being as social creatures as we are, we have the capacity to empathize and support others in need. Being sad will evoke that support from society. This is actually best shown in post-partem depression. Women who recently give birth are weak physically and emotionally. By inducing that kind of sadness, we fellow humans will go out of our ways to support that woman. However, that is a very special case that is generally considered different from unipolar or bipolar depressions. So now to depression. Depression is surprisingly prevalent in society and one would think that it would be evolutionarily selected against. However, depression is considered the result of the insufficient regulation of hormones, typically responsible for sadness. At the same time, we still know very little about this subject. Humans are so complex not just biologically but also cognitively and socially. It's the combinations and interactions of these factors that result in our behaviours. TLDR; Humans get sad. But sadness is good because it helps us understand what is bad in our lives. Depression is the result of our body not handling sadness correctly. But as always, humans are much more complicated than this.", "Because the main goal of our brain is not survival. It's \"a\" goal. It's one of many, albeit a very, very strong one. In a brain, we have a variety of different motives and emotions and thoughts. There are so many that our brains can abstract from logical thinking that many are divergent and contradictory thoughts. Who has never thought, at different times, \"I hate life\" AND \"I love life\"? Who has never thought \"That music is great\" and after hearing it 100 million times, thought \"That music sucks.\" We can hold many different thoughts and feelings at the same time. Nothing is really an either/or situation. It's not all about survival. Giving one's life so that another may live is not unusual at all, from all walks of life. Firemen make a profession out of potentially dying so others may live. It is not even a uniquely human instinct to \"not survive.\" *Most* mammals will give their lives for their young - not just humans. We also give our lives for many other reasons - for an idea or philosophy or whatever. One may kill themselves due to extreme and constant and never-ending pain. It is understandable. And, of course, mental pain is much worse than physical pain. Sticks and stones may break my bones, but they'll pretty much the bones will heal in 6 weeks, but words may stick with someone and cripple them their whole life. With people with mental illness, this is amplified. As far as why people get depression and mental illness, I guess that is just natural selection. The luck of the draw. The brain develops in a way that is not conducive to the current environment. But the brain is a physical structure, no different than a leg or an arm. Go google \"deformed babies\" and look at the images, if you have the stomach for it. If we are \"supposed\" to survive, why does a body get born with birth defects? Just natural selection, fetal development, and the effects of the environment. There is not just one goal of the brain. There's not one or two or three. There are hundreds and hundreds of goals/aspirations/etc. Under a set of particular circumstances, any one of them can come to the fore and subsume or quash the rest. **TLDR:** Survival is not the sole goal of the brain. There are hundreds and hundreds of goals, and under different circumstances, any of them might outweigh all others, and be acted upon.", "What makes you think our brains main goal is survival, I think its more along the lines of \"what can I do to not be bored\"", "That is assuming the brain is functioning at the level it is capable of, however, when someone commits suicide they are not functioning properly mentally. Basically, you're assuming rationality in our brains goals but we are irrational beings.", "Your brain doesn't have a goal. It's just a collection of functions that have turned out to be really useful in the whole survival-of-the-fittest thing. Like a function, it has expected inputs and its evolution has been predicated on assumptions about our environment and lifestyle. Our idle, sedentary lives are a proverbial wrench in the brain's system. The damage is expressed as neurotic mental illnesses such as depression and anxiety.", "Well, when programmers designed a bot to play Tetris for as long as it could without losing, it eventually just paused the game indefinitely when it was about to lose. The only way to beat the game was to not play at all. It's a bit the same with humans- when things are so bad and they never seem to get better, we just stop playing the game of life. The problem is that it's a short-sighted solution: things usually do get better but only in the long term. The brain is too focused on short term solutions than long term ones. I'm sure there's an evolutionary explanation like: \"we didn't get depressed in the old days so natural selection never weeded out the suicidal gene,\" but I wouldn't know too much about that to explain it through.", "In a maybe somewhat philosophical vein, our brains hardwired will to live long before we gained consciousness of death. So we have all these survival instincts but are now also faced with knowledge of this inevitable fate. Awareness of death came as surprise to our psyche, evolutionarily, right? On one hand, you can be convinced you keep living after death (perhaps due to strong survival instincts), making suicide trivial. On the other, consciousness of death may convincingly let one overpower their instinct to live as we can overpower other instincts we might consider ourselves burdened with. From this perspective, any justifying reason will do, doesn't matter, whether or not it overrides that instinct is up to/depends on the subject. To escape pain, to escape punishment, curiosity, nihilism, whatever. Not to mention, suicide itself may be an instinct. Cells in our body undergo a process called apotheosis, where they basically self-destruct if they determine themselves to be malfunctioning I guess, for lack of a better word. Also, it's interesting to wonder if an AI that gains consciousness or omniscience might just shut itself off -- maybe without instinct for survival (something all living things have at this point, all else being easily filtered out through natural selection far early on if it ever was there to begin with) the best course of action is just to abandon consciousness. Just an interesting thought experiment at this point I guess, but not an irrational idea in those circles.", "In my opinion, its not the \"brain\" its the mind. It has to do with lot of things, but lets look it deeper: Survival: back in the tribe days, people would get more stress, and with that stress they got more action, the mind would fuel them to do all certain things and to take action towards those things to survive, which include: - Saving family from other tribe members or \"attackers\" - Killing an animal to survive - Going on a dangerous journey And people were always in DANGER, they lived dangerously right at the edge. For them it was normal to expirience danger almost everyday. You see, when you're body is faced with a feeling of \"you are going to die\" or some sort of danger, it so much influences your nervous system that with all that action you feel, YOU MUST FIGHT, OR RUN. And after that body is REWARDING YOU, giving you dopamine, the body, mind brain will give you good emotions which are saying \"BRAVO YOU DID IT\" Those people who don't have them are doomed, they are gone - dead. People who don't expirience danger or some sort of fear, are bound to be depressed. Now in a society, this is exactly what is happening, we are not feeling stressed and in danger as tribe people were. We are shutting ourselves down. The whole point and diffrence is in ACTION. Depression is just that, lack of action. Depression (and it depends which) CAN be cured by taking action, moving, doing something, planing something. I truly believe if depressed people were to be put in wilderness for 1 week and needed to survive, or if the bear would chase them - some sort of danger - they would be cured. Its just a closing mechanism we all have. Fist you close to all the people you don't care about, then you close up to your friends, then to your family, and then you close to yourself, and after that when you do it, its just a matter of time when you will close to the World. When you do that, suicide is after that. But depression (+ suicide) and survival are in my opinion diffrent things.", "This is my take on why people become depressed and ultimately hopeless and giving up. People eat shit food and find little meaning in their life because they're a cog in a machine. No real goals, nothing to strive for. We are goal oriented towards thing we have a passion for. No passion, no directiom, nothing to look forward to. In the West we see the most \"exquisite\" of lives all around us. On internet, tv, movies, everywhere in our culture. We reflect this fantasy upon or own lives and draw imaginary short comings. Traditionally, cultures have taught that to find peace is through some form of enlightenment. Our culture promotes chasing the dollar. Their is no fulfillment in materialism. It is in pursuing what we love to do that leads to true happiness. For most people, living a menial life with a menial job filling their daily schedules 9-5 does not lead to this satisfaction. Most come home from these jobs and relieve themselves with a drug of some sort, whether it be sugar or alcohol, and everything in between. The perpetuity pushes many further into their mental abyss. I speak as someone with experience with years of being diagnosed with Bipolar, suffering many lengthy downs. I found that while my brain does have extreme chemical imbalances and this is not often looked upon optimistically, this can often work towards my benefit. The energy that the sensitive person can exhibit is a mechanism that has been used my brilliant minds throughout the ages to come to brilliant conclusions. From science to art, Van Gogh to John Nash(A Beautiful Mind), these minds experienced horrific tears in their psyche ripping away their reality from the common mind. These minds have dipped their toes in hell and stabbed their hands into the heavens returning with remarkable intuition and expression. It is my belief that these minds occur in the human species to further evolve culture and civilization. They question the norms because, to them there is no normal . Their mind is not the reality we know. This disconnect plummets these minds into a somewhat nihilistic depression, for lack of a better word. Because of many factors, the human mind reacts to its environment in a way that cause turmoil of the psyche, this can lead to intuition and discovery. Today's society puts people in boxes and prescribes no other remedy than anti-depressanta, anti psychotics, and mood stabilizers. Very infrequently do doctors take in to account environment and diet. This results in a massive depressed population. There is no hope in this current school of thought we have pertaining to the human mind. There is no solace in a pill, only numbing crutches. All minds are beautiful and have great potential to love and create in unique ways. It's unfortunate that so many potentially brilliant minds boxed into a room too small for them, having questions with no hope of answering and an environment with no hope of recovery, decide to end their life. I've been on the ketogenic diet for about two months now. I've never felt better in my life. I've been on every pill on the doctors note pad. They made me fat, slow, and more isolated than every before. Many times I found myself in positions wanting to end my life. I found myself making the plans. Suddenly, all this is gone. For some god damned reason this diet change has made my brain take a 180 keeping me consistently baseline with reality. I've never been more driven and I've never been determined. The one thing I have a lot of thanks for is drugs. Illegal drugs helped me get through my hard times. I numbed the pain and it let me stretch out my pains. It let me look at my demons frame by frame. It showed me the edge of this existence. Many illegal drugs have remedies, that I am certain, when combined with with healthier dietary conditions(NOT THE STANDARD AMERICAN DIET), Could drastically reduce depression and suicide rates. Old cultures accepted the use of drugs for spiritual and enlightenment purpose. Now you goto jail for doing this. This cultural change has played a key roll in changing the perspective of approaching your psyche. The drugs I speak of in a positive light in this context are, visionary substances, psychedelics, and empathogens. TL;DR: this is my opinion . Lots of bad food, unrealistic standards, no life goals, it takes a toll . our culture is the personifcation of materialism. Drugs are a crutch. I have bipolar my self. Van Gogh, John Nash. Brilliant, depressed minds. Questioning the norm brings in innovation. Psyche drugs should only be used on extreme cases and are dangerous. I use the Keto diet, used to be fat and suicidal; not the case anymore. it gave me life again. Drugs being illegal stop the use of man's oldest psychological tool. This post is referencing anecdotal evidence and my limited understanding of evolutionary psychology EDIT: sorry for not explaining quite like I would to a 5 year old, but this is difficult for me because I never would share the dark points the human mind could reach to an innocent mind. Nonetheless, I felt my experience should be shared. Also ,sorry for these long ass sentences and grammatical errors."], "text_urls": [[], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], ["https://en.wikipedia.org/wiki/Analysis_paralysis", "https://www.reddit.com/r/explainlikeimfive/comments/70iimp/eli5_if_the_main_goal_of_our_brain_is_survival/dn45g08/"], [], [], [], [], [], [], [], [], []], "score": [4087, 2211, 1892, 601, 549, 150, 120, 43, 35, 34, 33, 26, 24, 23, 18, 13, 11, 10, 10, 10, 7, 5, 5, 4, 4, 4, 3, 3, 3, 3, 3, 3, 3]}}, {"q_id": "70jblc", "category": "Repost", "title": "when the modern day calendar was created why did they opt not to have 13 months? Seems more tidy to have 13-4 week months.", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dn3kcu9"], "text": ["That would make sense if you were just starting from a year and inventing a way to divide it. But months come from observing the phases of the moon. Full moons are about 29.5 days apart, so we \"should\" alternate between 29 and 30 day months to line them up with the moon. But then you look at the year and realise that there are about 11 days left over at the end of your 12 months. So you add an extra day to most of the months to use those days up. Other calendars stick with months which track the full moon better, and add a 13th \"leap\" month to some years to deal with the 11 spare days."], "text_urls": [[]], "score": [6]}}, {"q_id": "70jv3o", "category": "Repost", "title": "What keeps people who work at KFC/Coca-Cola from stealing a sample of their secret recipes, reverse engineering them, and then selling them?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dn3o93o"], "text": ["Not a huge amount, really. We already pretty much know what's in these products (I mean, with Coke, you can basically just read the label). The difficulty is only getting the exact formulation and mixing right. For most people, the prohibitive part of that is not knowing how it's done - it's having access to the kind of production chain that can produce that product consistently and cheaply. Nobody buys KFC because their recipe is so much better than anywhere else. They buy it because it's convenient and consistent. Stealing or even improving on the recipe isn't (relatively) difficult, but entering the market as a competitor is."], "text_urls": [[]], "score": [13]}}, {"q_id": "70leqy", "category": "Repost", "title": "How do zero calorie energy drinks provide energy?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dn41nxc"], "text": ["They don't. They have a ton of caffeine in them. Which makes you feel energetic, but doesn't actually provide you with any more energy."], "text_urls": [[]], "score": [11]}}, {"q_id": "70letx", "category": "Repost", "title": "Why do fan knobs go from 0-3-2-1?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dn41gq0"], "text": ["It is hard to start a motor, it would take a long long time to start on low. Going 0 3 2 1 let's the fan start on High which gets it up to speed in a timely manner"], "text_urls": [[]], "score": [15]}}, {"q_id": "70lrlt", "category": "Repost", "title": "why do we get food comas after a satisfying meal?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dn44xu1"], "text": ["Your body has a limited supply of blood. Your arteries are constricted all the time to keep the pressure. When your muscles need more you receive sympathetic stimuli that dilates the arteries in your muscles and contract the ones where you don't need, the bowels. Your body wanna be ready to run from a lion. When you eat your body receives parasympathetic stimuli. Now it's time to digest, your bowels need a lot a blood and your muscles better not try to steal it. So it's a evolutionary strategy to make you feel sleepy so that you will only move if really necessary. If you try to move you may vomit, that happens in swimming pools often. You can see other signs of these stimuli: you need to do number 2 after eating, you pee when nervous. There are more, but I don't recall now."], "text_urls": [[]], "score": [3]}}, {"q_id": "70m5gq", "category": "Repost", "title": "Why do we yawn, and what does it do to our bodies?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dn480r7"], "text": ["The reason why we yawn hasn't been proven yet, but there are some speculative answers: * We yawn because we are bored/tired and this causes us to not take in as much breath as we normally do. So we yawn to help bring more oxygen in and take out carbon dioxide. * Another theory is that we our brain gets hot and we yawn to cool it down, this can actually be proven in many ways: 1. When we open our jaws that wide bloodflow to the brain actually increases which means more oxygen will be traveling upwards. 2. When individuals held a hot pack to their heads they yawned 41% of the time however when it was a cold pack they yawned 9% of the time. Scientists aren't actually sure why yawning is contagious however, but it seems to be linked with empathy and mimicry. This is because yawning may be a product of a quality inherent in social animals. In humans, it\u2019s the ability to understand and feel another individual\u2019s emotions. When we see happy people we tend to smile and imitate the same goes for unhappy people. So when we see someone yawning we imitate not purposefully but it's just a byproduct of how we work."], "text_urls": [[]], "score": [5]}}, {"q_id": "70mb7m", "category": "Repost", "title": "Why does body hair seem to reach a certain length and stop growing while head hair gets really long?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dn49ude", "dn49t95"], "text": ["Hair follicles go through a 3-phase cycle: * **Anagen** - the active phase, where the old hair falls out and the new hair grows * **Catagen** - transitional phase; hair growth stops and the outer root sheath attaches to the base of the hair * **Telogen** - resting phase; nothing happens. The length of the anagen stage determines the maximum length the hair can grow. Hair grows about a centimeter per month. Body and eyelash hair stay in anagen for 30-45 days; head hair stays in anagen for 2-6 years.", "Life, death cycles. All hairs go through the process of living and dieing at which point they fall out. 'Short hairs' just have shorter life cycles. AFAIK."], "text_urls": [[], []], "score": [24, 4]}}, {"q_id": "70mdco", "category": "Repost", "title": "If the Internet is basically a network of wires and computers, how does data navigate itself from one specific computer to where it needs to be?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dn4ajfy", "dn498fj", "dn4a0kw"], "text": ["_[rolls up sleeves]_ As others have said, it all comes to addresses, but there's a bit more to it than that, and it's sort of, kind of, magical when you understand it. This is long, but I'm writing it because I love talking about this stuff, and I hope it entertains somebody. First, you have to realise that a computer network is split into multiple layers. When engineers talk about these different layers, they normally do so in the terms of something called the \"[OSI model]( URL_2 )\", and as you can see, that has 7 layers. On the Internet, we normally only talk about some of them, because we group some together. However, all networks (including the Internet) at the bottom layer are physical, you're right. You are most likely to be using a wireless connection (WiFi), so there is some stuff going on there at a radio transmitter/receiver level in the gigahertz-range. If you're on your phone and not on WiFi, similar concept, you're just using 4G or 3G, or whatever. Wired stuff is normally in your local network going to be Ethernet, but the link to your ISP is probably going to involve copper cable, fibre, and a few other things (including, perhaps, microwave links - fancy!). Over the \"top\" of that physical layer is another layer called the data link layer. You will know some terms from this - if you've ever heard of a \"MAC address\", there you go, that's data link. Simplifying greatly, this is a way for all the devices on the same shared physical network to identify themselves and for communications to be clearly routed. A network router can say \"I have a message for this MAC address\", and whilst all the devices on that network might hear it (unless it's a \"switched\" network), only the one with the right MAC address will actually process it. And yes, that does explain how network interception can work, and why WiFi is considered insecure for a bunch of reasons. Now, above that, the Internet uses, as you may have heard, \"IP\", or the internet protocol. The thing you will be most familiar with is the \"IP address\", which normally looks like 4 numbers between 0 and 255 separated by periods: 192.168.0.1 or 127.0.0.1 for example. At this layer the stack looks something like this: +-----------------------+ | HTTP, DNS, etc. | +-----------------------+ | TCP or UDP | +-----------------------+ | IP | +-----------------------+ So for your HTTP (i.e. web) traffic get across the web, that protocol sits on top of TCP, which sits on top of IP. When you type in \" URL_3 \" into a browser, that gets turned into an IP address first using DNS, which uses UDP (normally), which goes over IP. When you collect email via IMAP, that goes over TCP, which goes over IP. Same for SMTP: goes over TCP over IP. With me? So this IP thing is sort of a big deal. Your local network has special IP addresses (they start 192.168... or 10.... probably). That gets into public IP addresses using something called NAT which is worth a post all by itself and is the bane of many an Xbox, Playstation or Nintendo Switch fan. However, the public internet, that's where magic happens. This is the point where all internet technologies - web, mail, Skype, your games console - ultimately have to come down to, and how your small little local network gets to play on the big open World stage. IP addresses are scarce. We sort of ran out of them some time ago (which is why more ISPs are moving to IPv6, something we won't cover here, but I can cover in a follow-up post if you want), but broadly this is how they get allocated. They're carved up into ranges or blocks and assigned to organisations that represent some part of the World, called [Regional Internet Registries]( URL_0 ). There are five of them in the World, and they are responsible for issuing IP address blocks to organisations in their territory who ask for an allocation. We have to get a little technical here: an IP address that looks like 4 numbers - a.b.c.d - is actually one number that is 32 bits (ones and zeroes) long. Each of the four numbers represents one byte (8 bits) of that number. If you're struggling with understanding that [this article might help]( URL_1 ). The reason I mention this is because allocations are described as the number of bits you can put into your \"net mask\". If I assign you 192.160.1.0/24 what I'm saying is \"24 bits of this number are fixed, you can vary the remaining 8 bits\", and that variation gives you 256 theoretical addresses (in practice, 255, and because one of them will need to be a gateway address, actually 254, but that's another discussion again). So when somebody says \"[ISP] has got a slash 8 allocation\", that means they have something like \"4.0.0.0/8\" and that is 16.7m IP addresses. A huge amount. In fact, 4/8 is a bit of an infamous block, but again, time, I'm digressing... If you're running a largish organisation, you can go to your ISP and say \"I need some public IP addresses\". They'll require you to justify the needs. If successful though, they'll give you a /30 (4 IP addresses) or a /29 (8 IP addresses). Now, how does my IP traffic find your IP addresses over the internet? We can finally talk about the clever bit: BGP. Your ISP has links to other ISPs. Physical links, with fibre optic cables, and network switches and all that jazz. Those connections will be regulated a little with a protocol called BGP which is basically what makes the internet work. Let's suppose you've been allocated 4.0.0.0/30. Your ISP will make sure everything in that range of IP addresses gets to you. They will then \"advertise\" via BGP that they have a route for that IP address range to their neighbours. Those ISPs they \"peer with\" will have other connections to other ISPs, and they will say \"Hey, I can get you to 4.0.0.0/30, with one hop\". Those ISPs _they_ peer with then re-advertise the range with 2 hops, and _their_ peers re-advertise with 3 hops, and so on, and so on. It might look something like this (with the numbers being hop counts incrementing as we get further apart via that route): 1 2 3 A ---- B --- C --- E | 2 \\ / 4 | D ---- Me You 3 In this example, I peer with 2 ISPs so when I want to get to you I have two possible routes via D or via E. My router hears from E \"I can get there in 4 hops\" and from D \"I can get there in 3 hops\", so my router goes via D. But if D goes down, I still have the other route, so this is a very fault tolerant setup. And this scales up, and up and up across the whole Internet. Every ISP that does BGP peering (called an AS or Autonomous System), has a routing table for every IP address on the planet and knows how many hops away it is via the peers they interact with, and sends traffic accordingly. This means any IP address can reach any other IP address, and the whole thing can route around outages. If you wanted a second ISP like me, you would go to your RIR and ask for an AS number, get a BGP router, and ask your ISPs to advertise your range like that. In practical terms it's a lot more complicated, but this is ELI5, and I've just tried to explain BGP4 AS peering... And that, in short (I know this is long, but I've missed a lot of detail), is how a bunch of wires and computers works across the planet, and why you can read my words that I sent from a machine in London to Reddit's servers in milliseconds, and how they can send them to you, wherever you are, and on whatever type of network you are using locally. I hope that makes you feel a small sense of wonder like I did when I first learned it. **TL;DR: the sort of marriage between mathematical graph theory and engineering that is indistinguishable from magic.**", "In short, addresses. Your computer has an address. The router it talks to has addresses for your computer and your ISP to use and all the systems the info passes through have addresses too. The data from your computer gets wrapped up in a Packet, with info about the data, and some addresses for where it is going. The router gets the packet, checks the address against a list of address ranges that it keeps and if the packet is going to a network it is on, it sends it to the right place. Rinse and repeat. If the address isn't one it knows what to do with, or is told to ignore, it drops it. It gets more complicated the more you look at it, but it's basically just a metric ton of addresses and directories working really really fast.", "It's pretty much like the post Office\\USPS. You post\\send a 'packet' out to an address (a bit like a post\\zip code). If it's local (on your network\\the postman's round) it gets delivered by the postman. If not, it sends it to the next distribution centre (router) that it is attached to. The routers have a list of, regularly updated addresses it knows about and where to send it to. So, once there, the same thing happens. This happens again and again until delivered - if it knows the address is local it delivers it, if not it sends it to the next link in the chain."], "text_urls": [["https://en.wikipedia.org/wiki/Regional_Internet_registry", "https://en.wikipedia.org/wiki/Dot-decimal_notation", "https://en.wikipedia.org/wiki/OSI_model", "www.reddit.com"], [], []], "score": [69, 6, 5]}}, {"q_id": "70mndx", "category": "Repost", "title": "Why do we get bad breath when we sleep?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dn4asmu"], "text": ["If you snore or breathe through your mouth at night, you\u2019re more likely to have bad breath in the morning than those who don\u2019t. In both situations, your mouth is even more prone to drying out, setting the stage for bacteria to grow. Some medications can cause your mouth to become dry overnight, worsening your halitosis. That\u2019s why older people, who are often on many medications, frequently find their breath more unpleasant in the morning. Smokers also may find they have bad morning breath. Smoking not only causes your saliva to dry up but also can raise the temperature of your mouth, making it a breeding ground for bacteria that causes bad breath."], "text_urls": [[]], "score": [3]}}, {"q_id": "70oi6x", "category": "Repost", "title": "Why 78 degrees inside the house feels much less comfortable than 78 degrees outside", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dn4oca4"], "text": ["There is little to no air movements in most homes which means your body does not cool as efficiently as warm air forms a pocket around you and stops easily absorbing body heat. As such temperatures have to be colder indoors to be the same level of comfort."], "text_urls": [[]], "score": [3]}}, {"q_id": "70q28f", "category": "Repost", "title": "Why is recall for which is Left and which is Right so hard for some people?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dn51wi5"], "text": ["My left or your left? Also, in a mirror, or not? Facing which direction? Left/right aren't as intuitive or natural as up or down. It's entirely relative, heavily context based. Whereas up/down is dependant on gravity, and a lot more intuitive. Also, stick out your hand. Extend your index and thumb. Which one makes an L. That's your left."], "text_urls": [[]], "score": [6]}}, {"q_id": "70qcvl", "category": "Repost", "title": "What does an orchestra conductor do?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dn548ge"], "text": ["Along with giving cues for certain parts to enter, the conductor also interprets the piece through the score. That's why you can listen to Beethoven conducted by one conductor, then through a different conductor you will notice some changes regarding the interpretation of certain markings. The conductor also helps the orchestra stay together for things like a fermata, which means the orchestra will hold one note for an undetermined amount of time. For things like this the conductor has to let the orchestra know when to release the note, otherwise everyone would release it at different times. This is also just one example, there are many spots in music where just looking at the music wont be enough to keep the ensemble together and at the same tempo."], "text_urls": [[]], "score": [3]}}, {"q_id": "70r3du", "category": "Repost", "title": "-Male Seahorses", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dn5aff9"], "text": ["> So what makes the male a \"male\"...is it that he has XY chromosomes or is his contribution is more sperm-like? His contribution isn't \"sperm-like\". His contribution is sperm. He produces sperm, so he's male."], "text_urls": [[]], "score": [4]}}, {"q_id": "70uidj", "category": "Repost", "title": "Why do so few storms happen in the morning\\daytime?", "title_urls": {"url": []}, "selftext": "I feel like I see way more in the afternoon or night time than during the day.", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dn602a7", "dn5z2f8"], "text": ["Meteorologist here. You are sorta correct. Thunderstorm activity, ignoring all other factors, is linked strongly to surface heating, which itself reaches a [maximum of around 4 pm]( URL_1 ) and a minimum of about 7 am. It is common for thunderstorm activity to closely follow this temperature curve. When temperatures are hot at the surface, there is lots of instability, meaning the lower levels of the atmosphere have lots of energy that can combine with moisture and release kinetic energy. If there is enough moisture, we see storms; if not, we might see turbulence, gusty winds, and in some places, dust storms. However there are significant variations. [This map]( URL_0 ) is from a 1980s study (Easterling & Robinson, 1985) that shows the hour of the day when summertime thunderstorm activity is most common, so 02 = 2 am, 15 = 3 pm, etc. This shows there is tremendous variation depending on where you live. The above map is based on human observations at federal sites. It's possible to develop a climatology differently using lightning strike data. [Here is the chart]( URL_2 ) (Holle 2013) color coded by time of day, broken up into PM (top) and AM (bottom) and covering all seasons. It follows a very similar pattern. Some findings: \\- Kansas and Missouri gets lots of storms around midnight because of support from upper-level systems and organization into long-lived complexes of storms. This is an important source of moisture for the corn belt because it tends to falls overnight and soak the ground. \\- The Gulf Coast gets storms early in the day because of the sea breeze, which replaces it with cool stable air in its wake. This sea breeze works inland and brings showers and storms with it. \\- The Rockies is tied closely to peak heating times, but you can see things fire a little earlier in the day along mountain ridgelines because of the higher terrain. Storms then spread out into the valleys later in the afternoon. \\- Offshore lighting in the Atlantic is probably due to Gulf Stream and land breeze interactions.", "Depends on where you are. I used to live on the coast and we had daytime thunderstorms almost every day (at around 2pm...You could practically set your watch by it). Exclusively nocturnal thunderstorms are an inland thing (though proximity to large mountain ranges also contributes to daytime storms). The driver is hot air from the land/sea. The heat from the ground produces a heavy updraft of hot relatively high-pressure air. This forms convection currents in the atmosphere, stirring things up, and \"priming the pump\" for a big rainstorm. However, that same hot air tends to prevent storms in areas without an overabundance of water. When it cools off at night though, the charged up clouds can \"fall\" into that low pressure area created by the cooling earth, and thunderstorm."], "text_urls": [["https://i.imgur.com/zMWBHpo.jpg", "http://www.goes-r.gov/users/comet/tropical/textbook_2nd_edition/media/graphics/daily_temp_lag.jpg", "https://i.imgur.com/NYGZNr4.jpg"], []], "score": [20, 3]}}, {"q_id": "70v15f", "category": "Repost", "title": "How is it possible that scientists can tell us about hundreds of planets light years awayt from us, but can't confirm the theorical 9th planet in the Solar System?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dn61jkt", "dn62mne"], "text": ["We can detect exoplanets (planets in other star systems) by the way they affect the light that comes from their Sun. When they pass in front of their Sun, they block a tiny bit amount of light from it, which our delicate instruments are able to detect. The theoretical 9th planet doesn't lie between us and any Sun, making this detection method impossible.", "Planets we discover in other solar systems are either: A) Enormous, and producing clear gravitational disturbances of the parent star. B) Transiting, so they pass between us and the star and cast a small but measurable shadow. C) Rapidly orbiting a small star, so multiple tiny gravitational wobbles from multiple orbits can be observed and confirmed because that planet's \"year\" is only 25 days. A theoretical planet 9 is none of those. It doesn't transit, is too small to produce significant gravitational influence on other planets, and has only completed a tiny fraction of a centuries-long orbit."], "text_urls": [[], []], "score": [9, 5]}}, {"q_id": "70vdi0", "category": "Repost", "title": "Christmas music really just seems to be the same 20 or so songs covered by 100s of artists. Why does no one ever release new Christmas songs?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dn659hk", "dn65jo5", "dn66jy2", "dn66ltl", "dn6e6wn", "dn655sd", "dn648ns", "dn6ku4d", "dn6okg9", "dn69o8i"], "text": ["Nostalgia is a big part. [Our buddies over at XKCD point out]( URL_0 ) that the big chunk of christmas pop songs came out right then the baby boomers were born, making these tunes part of their childhood.", "Christmas music occupies this weird space in the musical industry. It's all about the songs and the tradition. It all stems from singing carols. (Which has roots in religious hymns) The rest of the music industry is driven by the artists. \"Taylor Swift's new album!\" is generally how these things are advertised. New Christmas music does get made. There's *Believe* by Josh Groban, which is a \"new\" Christmas song. Relatively speaking. It was written in the last 20 years.", "I tried playing some more modern stuff a few years ago and immediately faced wholesale revolt from my family. Everything about the holidays is ritual, and tradition. It's not about new things, it's about doing the same old things. Occasionally new songs will make it into the Christmas canon, but for the most part tradition rules the holidays.", "A big factor no one has mentioned yet is that the majority of instantly recognizable Christmas songs are part of the public domain. This makes them much cheaper to use in any sort of medium so they perpetuate through the public consciousness. You don't have to secure rights (unless you want a specific artist's rendition of the song), so no one can deny you use of a public domain song for whatever purpose you want.", "They do, and they're all terrible. I heard a song called \"Text me Merry Christmas\" last year that made me want to slash my wrists.", "There are hundreds of Christmas songs but the most popular ones self-perpetuate as they are the ones people most associate with Christmas, so the radio & TV & stores play them to death to get everyone in the spirit. Artists do release new xmas songs every year and a few do catch on (The Darkness \"Don't let the bells end\" seems to get rolled out every year these days) but a lot are just quite poor (as with a lot of pop songs - for every solid gold #1 there's 1000 forgotten ones that sank) or awful cash-ins or novelty singles that have very limited appeal. Bad Religion and Bowling For Soup did xmas albums, XFM's \"It's a cool Christmas\" CD has some great tracks by indie artists, and Smerins Anti-Social Club did a great cover of Walking In The Air. I actually have a USB stick full of alternative xmas tracks precisely because I get sick of the usual stuff - there's more than 100 tracks on it. if I remember I might even post a list when I find it.", "probably because the classics make them a lot of money as compared to making a new song which is a gamble as to if it will catch on.", "Because that's how you get \"Grandma Got Run Over by a Reindeer\". Is that what you want?", "Trans-Siberian Orchestra has put out some great albums, Christmas Eve and Other Stories being my favorite. Lots of symphonic prog metal in the spirit of a Christmas concept album. Some absolutely great songs like An Angel Came Down. Good production and excellent vocals and musicianship. The overall vibe for me is that the writing dates to the days before the Christmas holiday was overly commercialized. The whole message is about kindness and redemption, not buying stuff. Some cynics could say that I have missed the point because they sell a ton of albums, concert tickets and get some airplay around Christmas, but that's not the point. It makes me remember what it's about, not want to go to the store. Their live show is absolutely wild, too, with a free merch signing afterwards. The band members come from all over the world and they are good. The Ravonettes had a good original Christmas EP out a few years back.", "Yea seriously. I tried making a modern Christmas play list a few years ago and it's super difficult. Plenty of artists and Bands do release Christmas songs, I just can't think of them. And I'm pretty sick of that Mariah Carey song. Lol Personally, I like \"Merry Xmas\" by dragonette"], "text_urls": [["https://xkcd.com/988/"], [], [], [], [], [], [], [], [], []], "score": [105, 92, 44, 31, 19, 12, 11, 9, 5, 3]}}, {"q_id": "70wvsj", "category": "Repost", "title": "if cameras take square photos, why are the apertures round?", "title_urls": {"url": []}, "selftext": "Is it that it TAKES a round photo and crops it? Or is the actual photo array a square? Bonus ELI5: how do digital camera technologies differ from older film cameras", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dn6g1f2", "dn6fseg", "dn6kq2j"], "text": ["You've sort of got it the wrong way round. The camera LENSES are round, because round lenses bend light much better. But the film the image is captured on is rectangular, for the same reason that all pictures are usually rectangles, easier to frame and they are easier to put onto walls. Modern camera sensors have just continued this. Also when light is bent by a round lens, the images around the edges are often distorted, by using rectangle sensors you are just cropping these out and getting a better image.", "There is a square area at the back of the camera that opens and exposes the film when the shitter is released, with digital the mirror lifts up when you press the shutter, and a square digital photo sensor is exposed. The aperture only lets in light and the image, what goes on the film/sensor is the final square insane", "Lenses are round, because round glass elements transmit light the best and provide the clearest image out the other end. (Most) apertures are round because round apertures work well in round lenses, and also provide pleasant looking results in photos. A [square aperture would cause square shaped blurry objects in out of focus areas in the shot]( URL_0 ) which is distracting and somewhat unpleasant. A round lens puts out a cone-shaped beam of light that resolves the image into a circle behind the lens, and then the sensor/film that captures the light is rectangular shaped, and sits in the center of that image circle. Images are shaped the way they are because of roll film, generally. A circular piece of film/sensor would technically capture more area out of the total projected image circle, but it's hard to make a roll of circles that tie together the way that a roll of rectangular frames of film does. They're also a lot harder to print and display. The outside edges of the projected image circle also suffer from vignetting and issues with diffraction and fine detail, and generally the crop provided by the rectangular film/sensor inside of that image circle crops out the best portion of the image, and leaves the dark/blurry/aberrant portion of the image."], "text_urls": [[], [], ["http://23527-presscdn.pagely.netdna-cdn.com/wp-content/uploads/2017/05/square-bokeh.png"]], "score": [46, 9, 7]}}, {"q_id": "70xael", "category": "Repost", "title": "What is gerrymandering? What are the advantages, disadvantages, criticisms, and solutions?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dn6j07g"], "text": ["Yarr! Yer not alone in askin', and kind strangers have explained: 1. [ELI5:Gerrymandering ]( URL_9 ) 1. [ELI5: Gerrymandering ]( URL_2 ) 1. [ELI5: Gerrymandering ]( URL_3 ) 1. [ELI5: What is Gerrymandering? ]( URL_0 ) 1. [Eli5: \"Packing\" and \"Cracking\" in Gerrymandering ]( URL_8 ) 1. [ELI5: Why is gerrymandering so common? ]( URL_5 ) 1. [ELI5: Examples of when gerrymandering _is_ necessary ]( URL_6 ) 1. [ELI5:Gerrymandering ]( URL_4 ) 1. [ELI5: How do you prevent/fix gerrymandering? ]( URL_7 ) 1. [Eli5: Why is gerrymandering an acceptable practice? ]( URL_1 )"], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/2ld2ii/eli5_what_is_gerrymandering/", "https://www.reddit.com/r/explainlikeimfive/comments/1pp1l6/eli5_why_is_gerrymandering_an_acceptable_practice/", "https://www.reddit.com/r/explainlikeimfive/comments/lk79p/eli5_gerrymandering/", "https://www.reddit.com/r/explainlikeimfive/comments/5jji31/eli5_gerrymandering/", "https://www.reddit.com/r/explainlikeimfive/comments/319m3w/eli5gerrymandering/", "https://www.reddit.com/r/explainlikeimfive/comments/63ppp0/eli5_why_is_gerrymandering_so_common/", "https://www.reddit.com/r/explainlikeimfive/comments/2aossn/eli5_examples_of_when_gerrymandering_is_necessary/", "https://www.reddit.com/r/explainlikeimfive/comments/5s3xte/eli5_how_do_you_preventfix_gerrymandering/", "https://www.reddit.com/r/explainlikeimfive/comments/53qdyb/eli5_packing_and_cracking_in_gerrymandering/", "https://www.reddit.com/r/explainlikeimfive/comments/3xvaq2/eli5gerrymandering/"]], "score": [6]}}, {"q_id": "70xefn", "category": "Repost", "title": "Why is Mexico so underdeveloped compared to the US and Canada?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dn6julw", "dn6pc8p", "dn6k8l2", "dn6jzjz"], "text": ["Yo ho ho! Yer not alone in askin', and kind strangers have explained: 1. [ELI5:why is mexico a third world country while the U.S and Canada are first world ]( URL_1 ) 1. [ELI5: Why is Mexico so poor compared to the US and Canada? ]( URL_4 ) 1. [ELI5: Why is Mexico so underdeveloped in comparison to the US and Canada? ]( URL_5 ) 1. [ELI5: Why is Mexico so much less developed than the other two North American countries? ]( URL_2 ) 1. [ELI5: How did Mexico end up poorer than the US and Canada? ]( URL_6 ) 1. [ELI5: Mexico is on the same landmass as USA and Canada. Why is it much poorer and more corrupt? ]( URL_0 ) 1. [ELI5: Why is Canada so much more developed as a country than Mexico? ]( URL_3 )", "The US fighting and defeating Mexico in the middle of the 19th Century didn't help Mexican development. I'm not an expert on Mexican history, but losing half of your territory (including Texas and California, which eventually became enormous wealth-generating states for the US), was a big blow. That was in turn followed by French meddling in Mexican affairs that further held back development, and finally years of revolution, civil war, and banditry in the late 19th and early 20th centuries. Taken altogether, while the US was consolidating its power, and faced no real external threats (save the Confederacy during the Civil War), Mexico withstood most of a century of conflict and turmoil. And more recently, the domination of areas by the cartels and other criminals has continued to impede progress. All that said, all of Mexico is not an impoverished wasteland - some areas are more well developed than others (with the flip side being that their are areas of the US and Canada worse off than the norm as well).", "Central and South America have a long history of American backed coups. If there's a leader who wants to improve life for his people at the expense of American industry they are removed.", "Cartels control the police in a number of places (not gonna estimate), multinational corporations exploit the poor, and governments (intentional plurality) suggest it's the citizens faults for the state of their nation - effectively sidestepping responsibility or understanding."], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/3jlczu/eli5_mexico_is_on_the_same_landmass_as_usa_and/", "https://www.reddit.com/r/explainlikeimfive/comments/2s73vc/eli5why_is_mexico_a_third_world_country_while_the/", "https://www.reddit.com/r/explainlikeimfive/comments/5pz27b/eli5_why_is_mexico_so_much_less_developed_than/", "https://www.reddit.com/r/explainlikeimfive/comments/3dh7ay/eli5_why_is_canada_so_much_more_developed_as_a/", "https://www.reddit.com/r/explainlikeimfive/comments/3pkrbl/eli5_why_is_mexico_so_poor_compared_to_the_us_and/", "https://www.reddit.com/r/explainlikeimfive/comments/5p1jhr/eli5_why_is_mexico_so_underdeveloped_in/", "https://www.reddit.com/r/explainlikeimfive/comments/6b7tdb/eli5_how_did_mexico_end_up_poorer_than_the_us_and/"], [], [], []], "score": [13, 9, 5, 3]}}, {"q_id": "70y8dz", "category": "Repost", "title": "How does a rail gun work like the one the Navy just tested?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dn6tfv0"], "text": ["Magnets. The rails that give railguns their name are lined with a series of powerful electromagnets. By flipping the magnets on and off in sequence, they are able to propel a slug at extreme velocities without the use of the explosive propellant found in traditional rounds."], "text_urls": [[]], "score": [7]}}, {"q_id": "7126oh", "category": "Repost", "title": "How can a company owe hundreds of millions, file for bankruptcy and then just start from 0?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dn7jtsa", "dn7jpql"], "text": ["They filed for bankruptcy protection, which allows them time to try to restructure the debt. If that fails they will go bankrupt and assets will be seized to try to cover all their debt(which will most likely just cover a small part of it) which is actually around $4.9 Billion Dollars, the $400 million is just the part of the debt that has payments due in 2018, $1.7 Billion due in 2019. They could re-start a company but would most likely be starting from scratch with no assets. Found an article that explains it pretty well; URL_0", "Toys R Us are filing for a chapter 11 bankruptcy. What this means is that all the owners who have invested money in the company hoping for a profit now loses all their ownership and all their potential profits. Instead the creditors that are owed $400M is given all the shares of ownership in the company instead of the money they were promised. All the company assets is valued at $400M so the new owners is likely getting most their money back. However they will likely try to restructure the company and maybe only sell off parts of it."], "text_urls": [["https://www.forbes.com/2008/09/25/chapter-11-bankruptcy-ent-law-cx_rb_0925bovarnickchap11.html"], []], "score": [7, 3]}}, {"q_id": "713bd9", "category": "Repost", "title": "Why is water desalinization not more prevalent?", "title_urls": {"url": []}, "selftext": "I believe there is technology still being developed that would optimize turning sea water into fresh water. However, would you not be able to just evaporate sea water to turn it to fresh water? That would separate the water from everything else, right? And could we not use renewables to provide the heat for evaporation, providing a green source of water to the dryer parts of the world? EDIT: I realize now that this is under economics. Not sure how to fix that...", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dn7s7tx", "dn7r7tg", "dn7rhmh", "dn7rayg", "dn7vn0s"], "text": ["Salt water is cheap and prevalent. The energy to turn that salt water into fresh water is not so cheap. As you point out, it's could be done by evaporating the water, but to do that with any significant speed you need to boil the water. That takes an *enormous* amount of energy. To get an idea of just how bad this is, raising 1000 gallons from room temperature to boiling takes about [1.5 MWh]( URL_0 ). Subsequently boiling that water takes a further [2.3 MWh]( URL_1 ), for a total of 3.8 MWh. With electricity at an optimistic $0.05 / kWh that's $190 per 1000 gallons. You can bring this down some by recycling some heat, but it'll still be tens of dollars per 1000 gallons just in the distillation step; you still have all the normal delivery costs. By comparison, typical water costs are less than $10 per 1000 gallons. The economics just aren't there for mass distillation of seawater. Other processes like reverse osmosis are less energy demanding so they're less terrible from an economic standpoint, but they're still not attractive compared to just using fresh water and performing relatively inexpensive filtration and treatment on it.", "It's an incredibly expensive and long process to build desalinization plants, and the plants require a lot of ongoing maintenance (all that removed salt has to be cleaned from the filter and dealt with), so it ends up being really expensive way to produce clean water.", "> However, would you not be able to just evaporate sea water to turn it to fresh water? That would separate the water from everything else, right? And could we not use renewables to provide the heat for evaporation, providing a green source of water to the dryer parts of the world? It turns out that it's more energy efficient to force the water through filters in a reverse osmosis process than to boil the water. But, it still takes a lot of energy.", "Because it's really expensive to do. You need a lot of energy to evaporate water and a country need a LOT of water. Country that are lacking water and usually also country with not a lot of money.", "Distilling water (boiling it) is the simplest, but not the most efficient way to desalinate water. But that's not what's stopping this... As others pointed out, even the cheap options for desalinization are energy-intensive given the immense volume of water we use. And it's not just the treatment that's difficult: the vast majority of the world relies on gravity to bring water to cities. If we desalinated seawater, we'd end up with a lot of drinkable water at sea level, requiring active pumping to deliver it pretty much anywhere inland, much less the places that could really use some water. Yet another cost on top. This would only become feasible with some unrealized energy source like nuclear fusion. Desalinating water on a wide scale would take up a huge chunk of our total energy use, so we'd have to have so much free, spare energy that we could afford to use it to do this. Currently, even if we wanted to, we simply don't make enough energy to carry on and desalinate all our water, and our current energy production methods couldn't expand enough to handle it. That said... I think it would be awesome! Think of all the rivers in the world that we have dammed up, drained, or destroyed in order to get water. The impact on fish, riparian habitats, etc. etc. We could drastically reduce our dams (just enough for flood control), stop pumping from all these rivers, and open these rivers up if we could all desalinate water and pump it where ever we needed to. It wouldn't be hard on the ocean (we sequester this much water out of the ocean already, just by holding back rivers instead of taking it directly), and our wastewater would eventually find its way to the ocean again, so there's no danger of like, worldwide saltwater concentration increasing. Entire ecosystems would return to huge parts of the world."], "text_urls": [["http://www.wolframalpha.com/input/?i=specific+heat+of+water+*+150F+*+1000+gallons+*+density+of+water", "http://www.wolframalpha.com/input/?i=water+latent+heat+of+vaporization*+1000+gallons+*+density+of+water"], [], [], [], []], "score": [11, 10, 8, 4, 3]}}, {"q_id": "715jxt", "category": "Repost", "title": "Why do words spelled correctly sometimes seem to look like they are spelled wrong or \"weird\" after I focus on the word or multiple repetitions of the word for a long time?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dn89roi", "dn8fe83"], "text": ["It's a phenomenon called \"semantic satiation\". You can look it up on Wikipedia. The basic idea is that a specific group of cells in your brain is involved in recognising each particular familiar word. If you repeatedly read a particular word that is familiar, the cells associated with that word get tired and your brain instead uses the group of cells it would normally use to decipher unfamiliar words", "I used to get this at high school, but I'd get it when I'd stare at the teachers head - I absolutely swear the teachers face became unfamiliar once having been stared at for a time. I told my friends and said to try it, they thought I was weird. Would this be the same thing? I'd guess it would."], "text_urls": [[], []], "score": [10, 3]}}, {"q_id": "715yhd", "category": "Repost", "title": "How are movies shot at 24 frames per second and have high visual quality?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dn8cczp"], "text": ["Movies have motion blur because of the way the film was developed, even films shot digitally have motion blur because of how the camera sensors work. Video games are perfect renderings (typically) of an exact scene. If an object is moving at 24 feet per second, it will look blurred in a film, which is realistic because that's how we see things. The same object moving one foot per frame will look choppy because in one frame it's at a location then the next frame it essentially teleport a perfect copy 1 foot from where it was. If your game supports motion blur, this is less notable but still a problem."], "text_urls": [[]], "score": [7]}}, {"q_id": "7169zu", "category": "Repost", "title": "When a train makes a turn, isn't its outer wheel covers more distance than the inner one? How come the train doesn't come off the tracks?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dn8faao", "dn8f9ky", "dn8zf08", "dn8f810", "dn8z0hb", "dn94ihi"], "text": ["URL_0 The wheels aren't cylinders, they're cones. The side that has to cover less distance in the turn rides up on the narrower end, so it makes more turns in less distance. Meanwhile, the other end does the same number of turns (solid axel), but since it is larger, it can cover the greater distance in the same number of turns.", "Train wheels have conical edges, not flat ones like say a car wheel. When the track turns left, this will cause both wheels to pull rightward. For the right wheel that makes the point of contact with the track a larger circle since it's pulling towards where the cone is broader; for the left wheel the circle gets smaller since it's pulling towards the thinner part of the cone. Now even though the shaft connecting both wheels spins the same amount, the inner wheel covers less distance than the outer wheel.", "< |-----| > Above is a simple diagram of a train axle with wheels either side. The important bit is the ' < ' shape of the wheel. When in a car going around a bend you feel yourself being pushed 'outwards' away from the direction of turn. This is a *centrifugal force* that always works in the same way. This exact same force 'pushes' a train outwards as it moves around a bend. The conical shape of the wheels ensures that the circumference of the particular point in contact with the rail is bigger on the outside(the side you feel you are being pushed against) than on the inside. . < |-----| > (turning left) . |_____| (track) . < |-----| > (turning right) . |_____| (track)", "The train wheels are not flat like car tyres: they have a conical shape, and this helps keep the train aligned through a process called [coning] ( URL_0 ). when a train hits a bend, its inertia forces the wheelset outwards, and then the outer wheel has a larger effective diameter than the inner wheel. This allows the outer wheel to travel further round the outside of the bend. It's not perfect and some slippage can still occur - which increases wear on the wheels but is not fatal, since the wheels have the \"lips\" to keep them on the tracks.", "I've been in the industry for 20 years... Contrary to popular belief the wheel actually steer around curves . There is usually a set of \"trucks\" that bolster a two axel set . The car body ( of many different types ) sits directly into a \"bowl \" on the trucks . The bowl has a pin in which the car body pivots and more or less turns while curving. It is a simple act of physics ... Weight distribution and gravity , not any fasteners of any kind ( believe it or not) hold the body of the car to the truck.", "The best explanation I've ever heard on this... URL_0"], "text_urls": [["https://i.imgur.com/skXgNKK.gifv"], [], [], ["https://civildigital.com/coning-wheels-railways-theory-purpose/"], [], ["https://www.youtube.com/watch?v=6-a3itxDiiQ"]], "score": [1011, 57, 30, 28, 8, 6]}}, {"q_id": "71adk8", "category": "Repost", "title": "How do people train pigeons to deliver messages and how do they know where to go?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dn98kid"], "text": ["Homing pigeons have been bread to always return home when they are released. So in order to use them you have to keep them at the destination from birth. Sometimes take them out on training flights to let them familiarize themselves with the environment to navigate quicker. Then you send the pigeon in a cage to the source of the message. There they can attach a note to the leg of the pidgin and release it. The pidgin will then fly home where the note can be retrieved from the leg of the pidgin. So the destination of the message have to be determined at the time of the birth of the pidgin."], "text_urls": [[]], "score": [5]}}, {"q_id": "71ehaw", "category": "Repost", "title": "Airplanes are large metal birds much higher in the sky than anything else. Why aren't there more reported cases of planes being struck by lightning?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dna4g3e", "dna4fx5", "dna4gp3"], "text": ["Um. Planes are struck by lightning all the time. In fact they're designed to be struck by lightning and carry on as if nothing happened. Back when the skin of the aircraft was aluminum, the plane just became part of the lightning discharge path. Now that a lot of aircraft are carbon fiber and other composites, they have to be careful to leave metal conductive paths for the lighting to flow through/around the aircraft.", "Lightning strikes planes all the time. But they are manufactured with lightning protection, so there hasn't been an accident caused by it since 1967. They are designed so that the aluminum frame of the aircraft is insulated from the interior, fuel tank, engines, etc. URL_0", "Aircraft will often divert around storms rather than flying through them. The actual conditions to get lightning around a cruise altitude (say 20k feet and above) is actually very rare due to the height being above most layers of cloud. Finally when aircraft get hit it's nornally a non event, planes are designed to deal with lightning strikes so the pilots will report it to atc and then the ground crew but other than that nobody really need no. Passengers may not even notice anything other than the fact that they are flying through a storm."], "text_urls": [[], ["https://www.scientificamerican.com/article/what-happens-when-lightni/"], []], "score": [9, 4, 3]}}, {"q_id": "71ekrx", "category": "Repost", "title": "How are we able to 'sense' when someone is looking at us or that \"gut feeling\" of something being wrong?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dna6obl"], "text": ["Your brain processes a lot more information than you are consciously aware. So you may see something in your peripheral vision or some noise that you didn't realise you noticed. This makes your subconscious uneasy as it is a base survivor instinct."], "text_urls": [[]], "score": [3]}}, {"q_id": "71flqn", "category": "Repost", "title": "How are old black and white movies remastered to technicolor?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dnadx93"], "text": ["It's essentially someone painting colours over the black and white image. These days with software, of course. Open a black and white image in Photoshop, set the brush tool to 50% opacity or to Hue/Color instead of Normal, and start painting colours over the image, and you're doing the same thing. They have to guess or decide what colours to make things, so the colours you see aren't accurate at all, and it can be slow, painstaking work. These days, there are algorithms that can try to automatically do this, analyzing the image and making guesses on appropriate colours. In fact, there's a subreddit and bot for doing that right here: /r/colorizebot. It works by analyzing existing colour images and trying to determine similar shapes and textures -- oh, that big flat thing with wavy shapes must be the ocean, which in other images is always blue, and that tall thing that branches out is a tree, which in other images is green. Sometimes it does a pretty good job, but it's still just making up guesses. You can never get the actual accurate colours, because that information isn't in the picture."], "text_urls": [[]], "score": [3]}}, {"q_id": "71g1wa", "category": "Repost", "title": "When the Federal Reserve increases or decreases interest rates, what does that mean?", "title_urls": {"url": []}, "selftext": "URL_0 How does this effect the deficit and budget, who benefits when there is a decrease and vice versa?", "selftext_urls": {"url": ["http://www.reuters.com/article/us-usa-fed-breakingviews/fed-balance-sheet-runoff-could-rock-fiscal-boat-idUSKCN1BV31I"]}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dnah54n"], "text": ["they change the lending rate, the rate that the banks pay to borrow money overnight. this raises the cost of capital for companies, makes them less likely to borrow to fund their operations, they slow their roll a bit. Sounds bad, but it causes civilians to save their money and it reloads the govts \"gun\" for spurring economic activity in a recession."], "text_urls": [[]], "score": [5]}}, {"q_id": "71gt6f", "category": "Repost", "title": "Why do different countries use different power outlets? Why isn't there a universal outlet?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dnanpct"], "text": ["Well, because basically, nobody wants to change their outlet design to another's. Neighboring countries have similar if not the same designs anyway. For example, my country has Japan's design because most of our imports come from Japan. It is easier too for imported products to just include adapters rather than change the dozens of outlets in millions of homes worldwide. It is not really necessary either. For example, the UK outlet have many safety measures that ensure that children will not be easily electrocuted, but if you insist that disposable chinese-made christmas lights must have the same precautions and cost of making, and essentially double their price, then you don't know economics."], "text_urls": [[]], "score": [4]}}, {"q_id": "71iclk", "category": "Repost", "title": "is eating meat really bad for us and if so, why?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dnax8cr"], "text": ["Yarr! Yer not alone in askin', and kind strangers have explained: 1. [What are the verifiable advantages and disadvantages to being a vegetarian? ]( URL_6 ) 1. [ELI5: Why is red meat bad for us? ]( URL_2 ) 1. [ELI5: Why do bad things happen when we humans or animals eat food from our species? aka Cannibalization ]( URL_4 ) 1. [ELI5: Why is red meat reportedly so unhealthy? ]( URL_1 ) 1. [ELI5: Is it really unhealthy to eat human meat as a human? If so, why? ]( URL_5 ) 1. [ELI5:What makes red meat so bad for you? ]( URL_3 ) 1. [ELI5: Is a Vegan diet objectively healthier? Not concerned about the morals behind it... ]( URL_0 )"], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/5wydt1/eli5_is_a_vegan_diet_objectively_healthier_not/", "https://www.reddit.com/r/explainlikeimfive/comments/2lqxfe/eli5_why_is_red_meat_reportedly_so_unhealthy/", "https://www.reddit.com/r/explainlikeimfive/comments/2f46u3/eli5_why_is_red_meat_bad_for_us/", "https://www.reddit.com/r/explainlikeimfive/comments/1a92px/eli5what_makes_red_meat_so_bad_for_you/", "https://www.reddit.com/r/explainlikeimfive/comments/33ngfs/eli5_why_do_bad_things_happen_when_we_humans_or/", "https://www.reddit.com/r/explainlikeimfive/comments/6r7bgi/eli5_is_it_really_unhealthy_to_eat_human_meat_as/", "https://www.reddit.com/r/TrueAskReddit/comments/1kmg28/what_are_the_verifiable_advantages_and/"]], "score": [3]}}, {"q_id": "71igmg", "category": "Repost", "title": "What happens to your vocal cords when you lose your voice?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dnaxuex"], "text": ["Yo ho ho! Yer not alone in askin', and kind strangers have explained: 1. [ELI5: How does losing your voice work? ]( URL_1 ) 1. [ELI5: What happens when you lose your voice? ]( URL_5 ) 1. [ELI5: What happens when you \"lose\" your voice? ]( URL_3 ) 1. [ELI5: What happens to our vocal chords when we lose our voice? ]( URL_7 ) 1. [ELI5: what happens when you \"lose your voice\"? ]( URL_0 ) 1. [ELI5: What's actually happening when you lose your voice? ]( URL_9 ) 1. [ELI5:What is happening when you \"lose your voice\"? ]( URL_4 ) 1. [ELI5: what exactly happens when you lose your voice? ]( URL_2 ) 1. [ELI5 what happens when you're losing your voice. ]( URL_8 ) 1. [ELI5 What happens medically when you lose your voice? ]( URL_6 )"], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/2r0fb5/eli5_what_happens_when_you_lose_your_voice/", "https://www.reddit.com/r/explainlikeimfive/comments/6z6dxk/eli5_how_does_losing_your_voice_work/", "https://www.reddit.com/r/explainlikeimfive/comments/3jvaki/eli5_what_exactly_happens_when_you_lose_your_voice/", "https://www.reddit.com/r/explainlikeimfive/comments/6ocj4n/eli5_what_happens_when_you_lose_your_voice/", "https://www.reddit.com/r/explainlikeimfive/comments/3767ku/eli5what_is_happening_when_you_lose_your_voice/", "https://www.reddit.com/r/explainlikeimfive/comments/32dv1c/eli5_what_happens_when_you_lose_your_voice/", "https://www.reddit.com/r/explainlikeimfive/comments/sdhft/eli5_what_happens_medically_when_you_lose_your/", "https://www.reddit.com/r/explainlikeimfive/comments/6uwg6d/eli5_what_happens_to_our_vocal_chords_when_we/", "https://www.reddit.com/r/explainlikeimfive/comments/15beaq/eli5_what_happens_when_youre_losing_your_voice/", "https://www.reddit.com/r/explainlikeimfive/comments/2fgg9k/eli5_whats_actually_happening_when_you_lose_your/"]], "score": [3]}}, {"q_id": "71j9y3", "category": "Repost", "title": "What part of the sleep cycle cause \"morning wood\" and why does it cause arousal? Is there a similar phenomenon that women experience?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dnb51ep"], "text": ["To my knowledge, as a vagina-haver, we don't have anything similar to morning wood. But our urethra is also separate from our sex organs."], "text_urls": [[]], "score": [5]}}, {"q_id": "71k9px", "category": "Repost", "title": "Why do babies like being rocked back and forth?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dnbc9zp", "dnbc61b"], "text": ["Before they are born, they get used to being rocked in utero when mom moves around. Rocking post-birth is familiar and, therefore, comforting. This is also why swaddling and saying \"shhhh\" calms babies: They mimic the tight spaces and sound of mom's insides.", "From what I've heard. It mimics the rocking motion babies feel when still in the womb. This gives them comfort."], "text_urls": [[], []], "score": [12, 3]}}, {"q_id": "71odbn", "category": "Repost", "title": "How is sound transferred onto a vinyl record? How is it capable of stacking all the sounds (bass, guitar, percussion, vocals, etc.) and still sound so clear?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dnc9r9m"], "text": ["All the various sounds we hear ultimately vibrate a single membrane in our ears. So if you are hearing the low rumble of a motor cycle driving by and the shrill sound of brakes being applied, both sounds vibrate your single ear drum but your brain can still tell them apart. For this reason we can layer sounds together into a single varying signal. In the case of a vinyl record it's in the form of 3 dimensional grooves that cause a tiny needly to vibrate. Those vibrations are converted into a pair of varying voltages along a wire."], "text_urls": [[]], "score": [4]}}, {"q_id": "71p3eh", "category": "Repost", "title": "Why do cleansers (or other products) label that they can remove \"99.99% of germs\" as apposed to 100%?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dnceizy", "dncek2z"], "text": ["Yep, pretty much. There will always be that *tiiiiny* percentage of germs that the sanitiser either missed or somehow had managed to survive the sanitiser. So to cover their legal asses, companies that make hand soaps/sanitisers say 99.99% rather than a full 100%", "There will always be some bacteria that resists. If that bacteria ends up being the next plague, ain't nobody gonna wanna take liability for not killing that."], "text_urls": [[], []], "score": [10, 6]}}, {"q_id": "71pgly", "category": "Repost", "title": "How does the the human brain ignore the second \u201cthe\u201d?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dnchaib"], "text": ["A part of the brain remember all the thing we have already read starting by \"How does the \" and it automaticly skip the second \" the\" cause it would make no sense based on our reading memory."], "text_urls": [[]], "score": [3]}}, {"q_id": "71pw3p", "category": "Repost", "title": "why is it that we always see so many new awesome ways to fight cancer and yet it seems nothing of it is ever being used?", "title_urls": {"url": []}, "selftext": "I mean, I see articles every week here on reddit about a new way to kill cancer cells etc. And it's been like that for years and yet none of these ever seem to be used to actually treat people.", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dncjoub", "dnczjlj", "dncm53r", "dndekuu", "dncvxm7", "dnckko7", "dncru97", "dnd8s2s", "dnd0nnt", "dnd58x2", "dnd1fax", "dncla8o", "dndnlq5", "dncnyjw", "dnd2vag", "dndtukk", "dndrjn6", "dndfg0a", "dndgniq", "dnck0hg"], "text": ["There are three main factors here. One is that medical treatments tend to get most of their news coverage when they're in early development, since that's when they're novel. It takes years for a new medical treatment to get from \"we're pretty confident this will work\" to mainstream usage, both because there are a lot of processes to follow to make sure it's actually safe and effective, and because when it's new it's really expensive and so the existing treatments continue to be used in some cases. The second is that unless you're an oncologist, you probably have no idea what methods are actually being used to treat cancer. Some of them are things you heard about a decade ago and now are the best choice and are used routinely, but there's no reason for you to know that. Survival rates for almost all kinds of cancer have gone way up in the last few decades, and while some of that has been due to improved detection, a bunch of it is new treatment methods. The 10-year prostate cancer survival rate has gone from 25% in 1971 to 84% in 2011, for instance. The third is that cancer treatment progress is incremental. It's incredibly rare that a new treatment or prevention method comes out and cuts the mortality rate for a kind of cancer in half or more. More commonly, a new treatment will come out that cuts the mortality rate by, say, 2 percentage points. For a common kind of cancer, that can be thousands of people per year that live when they would previously died, but it's not going to make that kind of cancer a non-issue. Cancer research is largely about stacking up a bunch of advancements like that, though, so that it can incrementally become less and less deadly.", "A quick explanation of drug development is necessary. Translational research takes place at different levels; basic, preclinical, phase I, phase II, phase III, and phase IV. At the basic level, the properties of compounds are studied. Potentially useful compound proceed to the next level of research depending on the data. At the preclinical level, potential drugs are tested in cells and small mammals like mice. This is considered pre-clinical research. If results are promising, an expensive clinical can be considered. Phase I clinical trials test for toxicity in healthy people. They test the range limits to look at side-effects. If positive results, next level trials proceed. During phase II trials, efficacy is tested in the disease model patient. Patients with the disease are treated with potential drug within levels established in phase I are observed. If positive results occur, a larger scale study begins. The larger scale study is actually phase III. At this point, the FDA will clear the drug if phase III trials show that new drug treats the disease better than what's currently out. If approved, a drug enters the playing field and is continually observed for what's known as phase IV trials. Phase IV trials are not the same, but play an important role to observe very rare side-effects. It is impossible to track 1:1,000,000 effects in trials with only 50K patients. This ensures safety of patients. See the history of zimelidine for an example of a drug that was pulled during phase IV. The whole process costs 100s of millions of dollars and takes 10-20 years. If the drug fails anywhere along the process, there often no recovery of the investment. This is why new drugs cost a lot. 1. Sensationalized media coverage of early research: most basic science doesn't make it to the end of clinical trials. The number is very slim that anything gets to a phase I trial. If they do, 9/10 of those will fail somewhere along the process. If you get early work in the news, you're not getting an accurate representation of what's actually going to make it. Look at phase II successes to get more accurate results. The drop off in phase III is much lower then anything before it. By then, you've weeded out a lot of unsafe drugs. 2. Drug development is slow: from beginning to end, a drug will take 10-20 years of development before we can see it in the market. 3. Cancer isn't a single disease: cancer is actually a bunch of diseases, depending on where you get it and what subtype. Each is different and can't be treated the same, unless we're talking systemic delivery like dox or other cell poisons. A study for treating pancreatic cancer is only for that type of pancreatic cancer. If it works, it'll work for that type of cancer, not brain cancer or any of its subtypes. 4. Cancer evolves: the scariest part of cancer is that even if a drug makes it to the end of phase III trials and it is effective at killing cancer, it isn't all-encompassing. Cancerous cells divide fast and introduce errors at the genetic level and eventually produce resistance to the drug developed to fight it. One-single cell left behind by a therapy (99.99999% effective) can result in recurrence years later, meaner and stronger than before. Why? The drug that didn't kill it is now unable to kill the new cells with an ability to resist it. Combination therapies are the fad in literature because of this. I'm firmly behind it. TLDR; news likes to exaggerate or reports on things early in development. Most therapies don't make it to the end for various reasons. Cancer treatment is specific. One treatment doesn't work on others so what you read is not universal if it gets past phase III. Finally, cancer can evolve to resist new therapies even if they work.", "Obligatory [relevant XKCD]( URL_0 ) Randall did a great job of identifying the problem with new drugs - sure, they kill cancer, but they also kill you. There are a million ways to kill cancer that we already have, but killing cancer while leaving the host alive is another problem. There's also the little problem that various types of cancer are weak to different things. It's like pokemon, in a way : you see a grass type, you use a fire move. You see a lymphoma, you use radiotherapy. There are many, *many* types of cancer, and they all demand slightly different methods of treatment. Back to the subject. So we find this new magic drug *VAPE420* that supposedly kills... idk, renal cell carcinoma cells really well. Eureka! Call the news! VAPE420 hits the headlines. We now have to make VAPE420 into an actual clinical drug. First, we make sure it doesn't kill too many normal cells in a petri dish. We then move on to mice. Does it kill them? No? Good. We then test them on healthy human volunteers. Phase 1. Does it harm them? Hopefully not! Good, they seem to be okay. We now test them on patients. Phase 2. Does it seem to work? Good. We now test it on even more patients. 3. Are there any major side effects etc? No? Great. We finally are able to sell the drug to the public, which starts Phase 4 of drug testing : feedback. This whole process can easily take 10+ years for *a single drug*. Congrats, you now have a single fire-type drug. We now need to make a water-type, a grass-type, a ground-type, etc etc etc. ------- Tl;dr 1. There are many types of cancer. 2. Different drugs are used for different types of cancer. 3. Drugs that kill cancer can also kill you. 4. Testing takes a long time so they won't kill you. 5. Many types x long time = ?", "It may not be obvious but it is happening. My brother had lung cancer (never smoked a day in his life) 12 years ago. Through debilitating rounds lasting 6 months of then standard chemo and radiation he achieved remission. The cancer returned last year with a vengeance, it had metasisizdd in half a dozen places through his body and this time they did some crazy shit where there took some of his T cells, reprogrammed them in a lab and then grew some more copies, and injected them back into his body. He was in remission 1 month later, all traces of cancer gone, with one freaking injection. It was some astounding, straight up Star Trek medical technology. In full disclosure, the first two days after injection his body had a severe reaction to the reprogrammed cells, and he had nausea and high fever, but that was it. He walked out of the hospital and felt normal for the rest of the month. Sure as hell beat chemo!", "Oncology BioPharm employee here: Awesome research is done every single day. Some at my company, some at the university level, some at government labs. Finding the 'cure' is relatively easy. Developing it, is not. You need to do ph0 or tox trials, this involves animal studies. Many great drugs die right here due to high toxicity. Remember cancer cells ARE human cells. The key is to be able to remove only cancer cells. Lots go away here. Then you need to do ph1 trials, this takes data from tox trials and starts dosing people, here you'll find out if the animal models predict toxicity to people. Lots fail here due to unexpected things. Then ph2 comes up, now you're looking to see if this treatment actually works. \"works\" is the key point. You can't do a null placebo, so you need to 'work' better than the standard of care. Lots fail here. Then ph3 which expands on dosing knowledge from ph2. Lots fail here. All of this takes years. Typically from discovery, you need a good 10+ years to do the trials above, plus the insane amount of characterization of the molecule and ALL of the degradation pathways with complete stability profiles for the drug expiry period.", "There is a huge lag time between treatment discovery and actual usage. Not to mention probably 90% of the discoveries you see in the papers never make it to the hospital, after testing reveals significant side effects, or that it doesn't work in humans only mice, or some other reason. Also the non-science media likes to hype up discoveries far more than the researchers are comfortable with. Headlines like \"miracle cure\" and \"life saving treatment\" are rarely that, and even the researchers discovering them wouldn't describe them like that.", "One analogy: Imagine the cure to cancer is like a long complicated staircase up a mountainside that we want to build. If we contact a bunch of carpenters and saying \"I need stairs up that mountain\", we're going to end up with 100 separate staircases being built at the same time, and maybe one of them will make it to the top. Many will fail though, and even the successful ones will take years and years to complete the job. Then there's also the fact that each type of cancer is different. Not every mountain is the same, and eventually we'd like to have stairs up *every* mountain. The good news is we can apply some of the same designs in each new staircase we build. We know this isn't the best way to get the job done. Instead, the way the treatment research works is \"We need stairs up that mountain, everyone build a piece and we'll put it together later.\" This way, no single person has to complete the whole task on their own. Also, the pieces that aren't useful for one mountain can be useful somewhere else. \"Curing\" cancer is a complicated process. I'm not in the medical field at all, but here's some layman examples of what those pieces of the staircase might look like. Some of these are more \"solved\" than others: 1. How do we identify cancer? *How do we make sure we avoid false negative and false positive tests? 2. How do we identify how \"bad\" the cancer is? *How do we determine urgency and severity of treatment? 3. How does cancer grow? How do the cells divide and multiply? What makes it so much different than regular cells? 4a. How do we tell cancer *cells* apart from other cells? * What sets them apart from other cells? The recent article about Poliovirus being used to fight cancer notes that the CD155 protein is more abundant in cancer cells than normal cells. That's one example. 4b. What can kill cancer cells *selectively*? * How do we kill the cancer cells without killing the normal cells? Is there something we can introduce to the body that ignores regular cells but still attacks cancer cells? How many mistakes does it make? Is it good at killing 50% of the cancer, or can it kill all of it? 4c. Is there anything capable of finding cancer cells? * As far fetched as it sounds, things like nano-bots are a brainstormed idea for this. If you can introduce a tool that is capable of searching out cancer cells and ignoring regular cells, then you can try and use them to kill the cancer cells. * Again, the recent article about Poliovirus mentions that the virus uses the CD155 protein as a receptor - which means it latches onto it. Since CD155 is more abundant in cancer cells, this ends up making Poliovirus \"target\" cancer cells more often than normal cells. The virus then does it's normal virus thing and starts a fight with the cell. Eventually white blood cells step as the club bouncers and throw both out the door. 4d. What is reliable at killing cancer cells? * IF we can find the cancer cells, what does it take to completely kill them? Some treatments just stop them from growing, and the tumour remains there until the cells die naturally and (maybe) get carried away. A benign tumour can still be a health issue. 5. How do we fix the damage the cancer caused? * How do we keep the cancer from killing the patient? 6. How do we fix the damage that the cure caused? * Whether we send in an army, a single spy, or a targeted strike-force, there's going to be some amount of collateral damage. How do we fix it? Chemo is an example of sending in an army. 7a. How do we prevent cancer from reappearing? * The poliovirus article has some information about the polio virus \"sticking around\" and helping the white blood cells identify cancer. It's like a snitch pointing out the problematic cells at the party so they can get thrown out before they hurt anyone. 7b. How do we make sure the \"prevention\" isn't damaging normal cells? 8. How do we prevent cancer from manifesting in already healthy patients?", "They are being used. Look into the death and survival rates of cancer over time. There has been a significant improvement in our ability to treat and cure cancer over just the last 20 years. Cancer isn't really the big C word anymore. If you catch it early you are fine in almost all cases, now.", "Mostly because when it comes to science, journalists are idiots. \"Cure for Cancer Found!\" makes a great headline, so that is the article they want to write, and that will color their view of the facts. The reality is novel treatments effective in a lab are found **all the time**. A blowtorch will kill cancer cells in a petri dish. Most will prove ineffective or impractical in people, and a few will become new treatments for very specific situations. Since that sort of steady, incremental change doesn't fit the cure for cancer narrative the reports are going for, they don't write a lot of follow-up stories.", "Because it looks MUCH easier on paper. It can costs millions if not billions of dollars into researching that \u201cnew method\u201d. Unless you\u2019re bill gates, you\u2019re going to have some trouble. Not to mention getting government authorization to conduct trials with experimental medicine and procedures, which can also be a problem. Also, people seem to forget that cancer is not just one disease. It\u2019s just a term that covers 100+ diseases, a \u201ccure all\u201d cancer drug is like saying we have a \u201ccure all\u201d mental illness drug or a lung disease cure drug. It\u2019s harder than it seems. A breast cancer cell is not the same as a brain cancer cell, they are completely different cells that just happen to divide uncontrollably.", "I work for a clinical research organization and here\u2019s what I can share. First off, before a drug or treatment can be released to the market, it will have to undergo 3 phases of human clinical trials. These phases can last for months or years. Phase I will assess the safety of the drug. This phase includes the study on Pharmacokinetics (movement of the drug inside the body - absorption, metabolism, excretion) and Pharmacodynamics (how the drug affects the body, i.e. side effects). This phase also includes identifying of the drug\u2019s proper dosage. At this phase, the drug will only be tested on a small group or population. Phase II will test the efficacy of the drug. This is usually done on a bigger population than Phase I. Most studies in this phase are with one group receiving the experimental drug while the other group receives a placebo. Phase III is large-scale testing and usually provides a better understanding of the efficacy of the drug. Once the experimental drug successfully passed this phase, the sponsor or company can now request for FDA approval for marketing. An additional phase, Phase IV, is done once the drug is released to the market. This phase studies the long term effectiveness of the drug. Note that in this phase, a drug may be removed from the market depending on the findings. Based from my experience, most Oncology studies I have been part of are currently on Phase I and II, very few are now on Phase III. This is why it seems nothing of it is ever used because technically, the treatments are not yet \u201cclinically proven\u201d for public use or marketing. Also, I noticed that the studies\u2019 experimental drugs are very specific to a type of cancer. Haven\u2019t really encountered one that is more general. An additional difficulty as well is finding or meeting the number of patients who are willing to undergo the clinical trial. This is why it takes years to complete the 3 phases and also the reason why the drug is expensive once released to the market.", "I heard a great quote about this from a cancer researcher \"If you're a mouse, and you've got cancer, we can cure you\" The wonder drugs work great on mice, which is when the media jump on it. Most don't work on humans. Those that do, don't get released for human use for another 10 years.", "'Cancer' is not one disease, it is a group of many different varied and complex diseases, one of the issues with calling it all just cancer is that in pop science it is often assumed that all cancer cells are the same. There are hundreds of different factors and as we are learning more and more in the age of personalized medicine, the disease can vary from person to person even if it is the same 'type' of cancer. We know a lot about a few different pathways that can lead to carcinogenesis and are learning more every day, but usually these findings lead to more questions. Cancer is your body's own cells and genes malfunctioning, so blocking or trying to affect the pathways in cancer cells can, like many others have mentioned, affect your normal cells too, which is why lots of people have secondary malignancies after treatment to kill cancer cells- radiation may kill the cancer, but it can also mutate the DNA in your normal cells. Others have already mentioned the lengthy and expensive process to get drugs to a clinical use stage, so I won't go into that. **TL;DR** cancer is incredibly complex and pop science gets a lot of things wrong & sensationalizes treatments Edit: Wow! Thank you for the reddit gold, kind stranger!!", "There is a long time from discovery to market, with tests, certifications and so on. Then, not all ideas pan out in practice. But, there is a bright side. We are getting better and better at fighting cancer. We have not found the silver bullet that cures all cancer yet, but we are improving on all fronts. Leukemia, which used to be a death sentence, now has a 95% survival rate. This moves fast. If you ever get cancer, don't look at any information older than, say 6-12 months, because it's outdated.", "Cancer is a strange thing. There are many things in cells that can go wrong that cause them to divide uncontrollably. We currently don't have a one cure for all cancer, but several cures and treatments depending on what causes it. New treatments are in the early stage of development and there are many hurdles to overcome. The most important hurdle is to make sure that while killing cancer cells that the side effects, if any (usually there are), aren't more harmful to the patient. It's a lot like coding where a bug is found, is fixed, but may cause other bugs that then need to be fixed. There is also a level of success rate. Some people react to some treatments very well while others do not. Cancer cells are tricky, and can sometimes hide from a treatment and the body's own immune system. Progress is still being made, though slowly.", "Stuff that works a certain way in a petri dish often doesn't work quite the same way in a functioning human body.", "If you are asking this question you probably can't afford the treatment. People are being healed. Just not people in your income bracket.", "Much of it is already being used. Just that they aren't as effective as you think, far from a cure all. Biggest problem is, every cancer is different. So it's hard to target it.", "I would argue the initial question. You do see them coming out but you have to watch for them. For example Novartis just got their new CAR-T technology approved which was heralded as a break through 5 or more years ago. Unfortunately, not all of the treatments do make it to patients for limited efficacy or toxicity.", "There's a lengthy time between Discovery and Application of these Therapies. Many of them are concerned with how they affect the Body after the treatment. Often these require Long-Time Studies that take, as the name implies, a really long time. Sometimes they are used on what I understand is called \"Low-Risk\" Patients. Which basically means their situation cannot get much worse but they are at the moment healthy enough and thus they can apply for medicinal studies and experimental treatments. *One of the Doctors I frequently talked to was quite a cynic and I really enjoyed his \"No BS\" attitude. He told me once: \"You know, we could have 100% Success Rate with Chemo- and Radiation Therapy if we stopped the Treatment only after all of the Cancerous Cells were gone. Sure, most of my patients would be dead but I guarantee that there wouldn't be any cancer cells in their bodies when we are done.\"* Source: Most of my next of kin suffer(ed) from Cancer, spent many Days in Hospital on Visit, asked this Question many Doctors. *Also I do want to note that at least in Middle Europe and from personal Experience the Quality and Success Rate of Cancer Treatments has come a quite long way (ignoring the fact that each patients case and type of cancer changes the survivability rating drastically).*"], "text_urls": [[], [], ["https://xkcd.com/1217/"], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], []], "score": [3016, 954, 686, 199, 110, 43, 13, 9, 9, 9, 9, 7, 7, 6, 4, 3, 3, 3, 3, 3]}}, {"q_id": "71tp8e", "category": "Repost", "title": "Why does a familiar word sound unfamiliar after you overly repeat it?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dndfbb7", "dndumny", "dne2ogq", "dndp16p", "dndvyya", "dndfeau", "dndumt2", "dne2ctl", "dndvwnm", "dndz0qp", "dndxwhw", "dne18aw", "dndvkgc", "dnduhjc", "dned4rd", "dne8my1"], "text": ["It is a phenomenon called semantic satiation. When you hear a word, your brain isn't really paying attention to the sounds, it is translating those sounds into an idea, and is primed to put it together with other words to form a more complex idea. When you repeat a word over and over, your brain stops recognizing it as a word, and it breaks down into sounds that really have nothing to do with what the word means.", "Others have already explained this accurately; I wanted to add a bit about things related to this. Consider the brain. Natural selection has determined we need to process things very quickly to react to them. In this way, the brain abstracts an output of senses into a \"symbol\" that it can process readily. When observing children's pictures of houses, you will notice that after five years old or so, they will nearly *always* put a door knob on a door. Even if it's more of a handle or something else, they will put the thing there that their mind associates with \"mechanism for opening doors\". This makes drawing difficult because you need to see the world without abstraction in order to replicate it. One exercise to do so is to draw the \"vase or two faces\" picture while saying the part of the face you are drawing until you can do both sides without messing up. It forces you to remove the association of the words with the image you are making. As you get into this mental state, you will begin to lose the symbolic association your mind makes with the items in the world and see them for the shapes and colors they are. This is like a grander scale of losing track of the meaning of a word. It's losing track of the meaning of everything you see while simultaneously really seeing it for the first time. If you're interested in more, the book \"Drawing on the Right Side of the Brain\" is a great read. Sure, left/right brain stuff is scientifically inaccurate, but as a metaphor for linear vs abstract thought, it works.", "You have stumbled on to a very deep question about how we understand the world. This issue is a major concern for AI studies (Artificial Intelligence, since this is for 5 year olds) The human mind has an amazing ability to take a single word and understand a complete concept. Take the word \"chair\" for example. We all just know what a chair is. Size, color, shape and many other features may be in the background but your mind instantly has the idea \"chair\". This is the default position in your mind as it is most likely what you need. However if you start repeating the word \"chair\" your mind refocuses on the actual word. The sound, the intonation, the break down of the parts of of the word. This feature of the human mind, the ability to move from a lager abstract concept of a single word to a specific breakdown of the same word is very interesting to anyone trying to create computers that actually \"think\" like humans.", "To add to this, it is similar to when you're eyes look at something for too long and don't focus as well on the thing you are looking at. The receptors in your eyes start to get too used to the stimulus and send less new information to the brain. That is why eyes move around a lot when looking at anything such as when reading and looking at television. Sounds will be similar because it would be the receptors receiving the same exact stimulus over and over again so your brain begins to focus less on the whole words and the meaning becomes fuzzy much like an image becomes less focused.", "It's basically the same confusion and irritation you experience realizing you are manually breathing, manually holding your jaw up (neither closed or fully open), manually blinking, your ears pop when you swallow, you have to find a good resting place for your tongue, what direction your pupil is facing when you sleep, etc. The trick is to not think about it, but now that I mentioned these things, you are thinking about them all.", "It's called semantic satiation! There were some experiments done in the '60s and apparently what happens is a specific pattern is triggered in your brain by a word/phrase as you're parsing its meaning. If you do this repeatedly, the intensity of the reaction decreases", "It is actually something called Jamais Vu, a similar phenomenon to Deja Vu. Semantic satiation is the end result of the process. heres a simple video that explains it. URL_0", "In a word: uniqueness. When teaching a dog a trick with a word, like to sit, or to lay down, the dog doesn't *actually* understand what the word(s) mean; they realize the unique sound that the command makes relative to the sound of everything else, and those unique combinations of sounds \"to sit\" trigger a part of the dog's brain to react to it. It's very primal, but the same effect applies to humans: we choose different sounds for different words because unique sounds allow us to separate meanings for the different particular sounds. We do this for THOUSANDS of sounds and attach more *meaning* or *command* to these sounds whereas you would only teach a dog a few sounds with probably a single command that the dog should react with. When you mess with the \"uniqueness\" of sounds, by repeating it over and over again, it starts to lose the reason why it was a word to begin with, and, to your brain, reverts to nothing more than a generic sound that your brain has very little remaining synapse connections to (at the moment) but also intensely trying to understand because it does know what it should mean as the few synapses do trigger a larger understanding in your brain (\"it's on the tip of my tongue\" phenomenon)", "Probably because you start incrementally realizing how absurd the word is, and how it sounds. Then language itself starts breaking down and you wonder what you sound like to people who don't speak your native tongue. Then you start feeling sorry for the dog who has to put up with it all day.", "I... Have some learning disability and this doesn't effect me. Can someone explain how this feels? I've seen this talked about a lot and I can repeat a word 100s of times and never get to this point.", "the neurons in your brain which encode the meaning of the word stop firing, so you do not \"feel\" the meaning anymore, because they have adapted (the same underlying mechanism which causes you to see green when you close your eyes after looking at red) but the neurons in your brain which encode the sound of the word are still firing so your brain feels the sound but not the meaning", "I don\u2019t recall experiencing this audibly, but i do know if i write a word repeatedly i start to question it\u2019s spelling even if it\u2019s correct. Probably the same phenomenon though.", "a podcast called \"a way with words\" has a good term for this. they called it the \"gnarly foot\" syndrome. essentially, the longer you look at your foot, the weirder it seems we have such an odd appendage on our body. Search for that episode. explains this pretty well - better than we can do here.", "So, I've a question in-relation to this one: who else out there doesn't actually experience this? I can't imagine I'm alone in that regard.", "Many of the top answers are incomplete. The answer is neurologic. Here's a true Eli5 answer. Neurons are used for your senses. Neurons are kind of like guns firing. When you continuously expose yourself to a sensation, a neuron cannot continuously fire, just like a gun cannot continuously shoot a bullet. Just like the gun has to reload, the neurons also have to take some time to reload. There are several other examples: Try staring at something for a long time. You will eventually stop seeing it. When you wear a cap, you eventually stop feeling it. Throughout the day you adapt to your clothes being there and are not continuously \"feeiling\" them. Try smelling some perfumes. As you smell one a few times, you start to get used to it. Many perfume places have a coffee bean scent, which helps to reset the neurons.", "There's a great video on this that explains it far better than I could, ( URL_0 ) but basically, when you overstimulate the neurons necessary for recalling something (A word for example) they get exhausted and can't continue to be stimulated. That's why when you say pencil once, it's normal, but when you say it for the 67th time, you're like \"How the heck is this even a word?\""], "text_urls": [[], [], [], [], [], [], ["https://youtu.be/CSf8i8bHIns?t=311"], [], [], [], [], [], [], [], [], ["https://www.youtube.com/watch?v=KV9oeivWXlo"]], "score": [4206, 1528, 397, 154, 107, 53, 18, 16, 15, 12, 12, 11, 7, 5, 4, 3]}}, {"q_id": "71xs7q", "category": "Repost", "title": "Why might it be so hard for me to fall asleep again after waking up, but once my alarm goes off and I'm supposed to wake up, I suddenly can't stop hitting snooze and going back to sleep?", "title_urls": {"url": []}, "selftext": "Been experiencing versions of this pretty much my entire life, including now since I just moved into a new space and I'm not used to the light streaming in or the sounds of traffic in the morning yet. So I always wake up a few hours early, and, despite being still exhausted, can't fall totally back asleep. I'm always in a half-asleep state where I'm not totally aware of time passing, but still very aware that I'm not asleep. But when my alarm actually goes off and I HAVE to get up, my body suddenly stops tensing up and my brain stops running and I have no problem hitting snooze over and over again just to catch a few more minutes of sleep. Why does this happen? Is there any method I can use to alleviate this issue?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dnebkvw"], "text": ["It basically has to do with your sleep cycle. Through the night, you come in and out of very deep (REM) sleep 4 to 5 times. When you wake up naturally, it\u2019s because your body was already at a point of very light sleep so it was easy to wake up and stay awake. By contrast, your alarm is probably waking you up at a deeper point in your sleep cycle so your body doesn\u2019t want to wake up yet. There are apps on the App Store that will track your sleep patterns just by setting your phone on the nightstand next to you and it will then wake you up at the lightest point of your sleep within a 30 minute window. I won\u2019t name the one I use because I\u2019m not here to promote but it has been extremely effective for me."], "text_urls": [[]], "score": [36]}}, {"q_id": "723jzu", "category": "Repost", "title": "How do those huge construction cranes that are tens of stories high get to where they are?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dnfhhbk"], "text": ["Bit by bit. Seriously, they are sent in sections and built up. This gif should help explain it. URL_0"], "text_urls": [["https://imgur.com/dTSHCNY"]], "score": [9]}}, {"q_id": "723nra", "category": "Repost", "title": "Why do your legs fall asleep when you sit on the toilet for a long time but not when you sit in a regular chair?", "title_urls": {"url": []}, "selftext": "Edit: Thank you for all the advice on why it takes me so long to shit. My problem, however, is getting distracted by my phone and just sitting there after the business is done thus causing tingling legs. Guess that's more of a personal problem though. I could have googled but thought of y'all instead- take that how you want. (: Edit 2- I'm strangely proud that a question about the shitter has been my most viral post.", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dnfv8xv", "dnfi7kw", "dnfvmk0", "dnfus1w", "dnfrs36", "dnfvor7", "dnfnwpv", "dnfsv3f", "dng80yh", "dng8esj", "dng35a5", "dng41nx", "dnfqsdr", "dnfyxhs", "dng4m3s", "dnfvug4", "dnfu6n5", "dng48eg"], "text": ["The toilet seat puts pressure on the nerves leading to your legs by allowing your butt to sink into the giant hole in the middle. This puts the bottom of your femur (thigh) under a lot of pressure, when that area would normally not be because our butts are designed to carry fat to protect our sacrum (tailbone) and the nerves that go through it/ around it. What happens is essentially the same thing as if you were to lean on one arm for too long- it's not so much a blood flow issue, although that can contribute in a minor way, but rather the compression of nerves. We discussed this in a class in my nursing program (I'm studying to be a registered nurse) because they make a pillow referred to as a \"donut.\" It's supposed to help older adults feel more comfortable in a hospital bed, (especially because they don't have butt fat anymore) but instead it has the same effect as sitting on the toilet for hours on end. Companies try to market it to prevent pressure ulcers on patient's rear ends, but it's actually bad for them. Now you know! Edit: wow guys! Thanks for all the upvotes, and your wonderful comments :) Other users have pointed out the actual muscles and nerves involved: the toilet seat puts pressure on the piriformis muscle, which then compresses the sciatic nerve. That nerve compression is what causes the unpleasant feeling.", "Toilet seat has a rim. Smaller surface area means it presses on your legs with higher force. So has higher tendency to slow down blood going into your legs. Regular chairs on the other hand are flat, have higher surface area, so less pressure, and less force pressing on your legs. So less tendency to slow blood flow. Edit: the comment below me corrected me. The higher force presses on the nerves, not blood flow. thank you.", "Doc here, I know it's late but here's an actual explanation: The feeling that you get is due to what we call neuropraxia, which is the mildest form of nerve injury. When you sit on a regular chair, your weight is distributed primarily on your ischial tuberosity(i.e. \"sit bones\") and other soft tissue meant for weight-bearing. When you sit on a toilet seat, the weight shifts to where it's putting your weight onto your sciatic nerves(the major nerve in your leg). This compression of the nerve causes this mild, reversible nerve injury and is responsible for the \"falling asleep\" feeling you experience.", "same amount of weight, smaller surface area. you know how a bed of nails works? if all of your body was on one nail, that one nail would hold all of your weight and poke into you with all of your weight. (this has a name: normal force is the force that pushes you back when you push on something.) on a bed of nails, you're suspended on many, many nails, and even though theyre ALL sharp, each nail only holds a tiny fraction of your weight, so it pokes into you less. (also the reason snowshoes work. more surface area > each inch of snow is holding less of ur weight and is less likely to crumble.) so, all of ur body weight is on the seat of the toilet, so a larger fraction of ur weight is on each inch of rim, because there's less seat, so it's \"poking\" you more. where a normal chair has more even weight distribution. more force on each inch of ur body > more likely itll fall asleep. (ive also had my butt fall asleep after sitting on a chair for a looong time. it just takes longer.)", "Wouldn't the concave shape of the toilet seat cut more circulation off than say the convex shape of a proper chair? As far as I can tell, most toilet seats including the one I sit on this very second, has a concave shape", "Have you ever had someone sit on your lap and thought, \"wow, they have a boney butt!\" What you're feeling are the ischial tuberosities, the lowest part of a bone of the pelvis. When sitting on a flat surface (in this case a chair) these boney projections prop up the body away from the nerves that run from the spinal cord down into the legs (the sciatic nerves). Because the ischial tuberosities of the pelvis are fairly centrally located, when sitting on a toilet seat they don't prop up the body - and as a result you compress the sciatic nerves. Nerves really don't like to be pinched, pulled, or compressed. I think everyone has \"hit their funny bone\" enough to understand this quite nicely. Note: the reason the answer to this question has nothing to do with blood flow is that the main blood supply to the lower limbs are from the femoral arteries, which are located on the front of the legs, not the back.", "Also I think due to the angle you're getting more direct pressure onto your sciatic nerves", "Do you reddit on the toilet (of course you do, don't bother answering). Your elbows are probably digging into the tops of your thighs and the hard seat rim into the bottom, and the combination is enough to reduce blood flow, causing your numbness.", "Piggybacking to say: also why does my ass hurt/fall asleep after 1 hour of a flight across the US but feels fine after 6 hours on a computer chair", "The rim at the edge of the toilet seat puts pressure on a nerve that runs along the back of your leg called the sciatic nerve.", "The same reason being stabbed with a pencil will penetrate skin but being hammer punched with the same force doesn't. The weight of the body is evenly spread out over a chair, but when on the toilet the weight of the body is concentrated on a smaller portion of the leg, which also has major blood vessels running where that pressure is applied.", "You don't notice it but you reposition and adjust on a regular chain frequently. On a toilet you don't really have that luxurie as your ass is inside of a hole. You can move your legs a bit but that's it. You have to move your butt from the hole to unpinch those nerves. Lots of people get distracted by their phone and don't even realize their legs are gone until they try to move them. Your legs will fall asleep in a regular chair if you keep them still long enough", "Because my arms are rested on my legs while I visit Reddit cutting blood flow to the lower legs making me paralyzed and my legs useless.", "Actually, my legs fall asleep even when I sit on chairs and sofas too. As long as whatever you're sitting on reduces your body's circulation it can make your legs fall asleep.", "I'm guessing it has to do with the fact that there is a hole for you ass in the toilet seat, for obvious reasons. This put more stress on the back of your thighs which blocks off blood flow. That's my logic anyway.", "Because your legs are way more inclined in the toilet (for you to dump easier), and you are literally sitting on a hole so the blood in the area that is in the border has a difficult time trying to reach your legs due to pressure.", "I think leaning forward creates more pressure as well as the relatively thin surface your legs are supported by. I have crappy posture to begin with and I think it gets worse in there. I also spend too long sitting like that. I spent the first 30 seconds going, the last minute cleaning up and the other 20 minutes playing games on my phone in the one place in the house where nobody can come bother me. Except for the cat. That motherfucker follows me everywhere and bites my toes while I poop.", "It\u2019s because when you sit on a chair, your gluteal muscles (butt muscles) and the ischium (butt part) of the pelvis take most of the weight. When you sit on a toilet, your gluteal muscles and ischium are suspended by the basin of the toilet and most of the weight is beared by the semitendinosus and bicep femoris muscles (big parts of your hamstring). Coincidentally these hamstring muscles are right behind the sciatic nerve, which is the largest nerve in the body, and is solely responsible for almost all of the feeling and motor function of the leg. So when you sit on the toilet, after a while, those muscles put pressure on that nerve and cause your legs to go numb. EDIT: spelling"], "text_urls": [[], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], []], "score": [2521, 1774, 273, 244, 45, 17, 8, 7, 6, 5, 5, 5, 3, 3, 3, 3, 3, 3]}}, {"q_id": "7241u8", "category": "Repost", "title": "how does the us government spend so much on healthcare and still doesn't have a single payer system?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dnflbpp"], "text": ["The 18% GDP are *not* spent by the government, that's the whole point. The reasons why US healthcare spending is so high are: * Insurers are for-profit companies, their profits have to be paid for. * Going through med school is very expensive, so doctors need a very high salary - the healthcare system is also paying for their student loans. * Due to the many insurers, pricing and billing end up being horrendously complex, and the system has to employ tens if not hundreds of thousands of people to negotiate bills. * Since many people are uninsured and poor, they cannot get preventative care, so things that could be healed easily and cheaply early on often go untreated until the people end up in the emergency room, where the hospital has to treat them (very expensively) even if they can't pay, so everyone else ends up paying for them. * The healthcare system also pays for billions of marketing dollars spent by drug companies to convince people to ask their doctor for their product over a virtually identical cheaper competitor."], "text_urls": [[]], "score": [6]}}, {"q_id": "72461k", "category": "Repost", "title": "How can we know that the observable universe is 46.1 billion light years in radius, when the furthest object we can see is 13.3 billion light years away?", "title_urls": {"url": []}, "selftext": "The furthest object from our point of reference is [13.3 billion light years away]( URL_1 ) from us, but we know that the universe has a diameter of [92 billion light years]( URL_0 ). I know the reason for the universe being bigger than 28 billion light years (or so) is because space can expand faster than the speed of light, but how exactly can we measure that the observable universe has a radius of 46.1 billion light years, when we shouldn't be able to see that far?", "selftext_urls": {"url": ["https://www.space.com/24073-how-big-is-the-universe.html", "http://www.independent.co.uk/news/science/most-distant-object-in-the-universe-spotted-by-hubble-space-telescope-shattering-record-for-the-a6911096.html"]}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dnfn6v0", "dnftftq", "dnfrxx5", "dnfn3bd", "dnfprb5", "dnfrs21", "dngksw5", "dngpirx", "dngjy05"], "text": ["First off, while its true that the furthest object is 13.3 billion light years away, we can actually see stuff 13.8 billion light years away. This \"stuff\" is the beginning of the universe, back when everything was just one giant hot soup of matter and energy, rather than distinct objects. Second, when we say we see something \"x billion light years away\" what we really mean is that we are seeing light from something x billion years ago. This is relevant, because it means that the thing we see is not happening in \"real time\". So, its location in space that we see it right now is, say, 13.3 billion light years away from us, but that was (roughly) 13.3 billion years ago. In that time, the empty space between us and that galaxy has expanded, meaning if you could send an instantaneous probe to wherever that galaxy was now, it would have to travel much further than 13.3 billion light years to reach it. We just get the number 92 billion light years by assuming the universe expands at a constant rate, and calculating how far away the edge of the observable universe is today (instead of back in time when we see it). Also, the universe is *at least* 92 billion light years. It could definitely be bigger, but 92 billion is just the largest we have a reference point to calculate from.", "Imagine someone (Alice) standing 14 meters away. They roll a ball toward you at 1m/s. It takes 14 seconds to reach you. That would be light in a universe that isn't expanding. Alice was 14 m away when they rolled the ball, it took 14 sec to reach you, and they're 14 m away now. Now imagine next to that person, a second person, Bob, standing on an infinite treadmill moving away from you. Bob also rolls a ball toward you. Imagine both balls reach you at the same time. The first thing you'll now is that Bob must have been closer to you than 14 m because his ball has been moved backward by the treadmill. (Remember that all balls (light) move at basically the same speed) So we can figure out that light we see from 13.8 gya (giga years ago) was actually emitted by objects closer than 13.8 billion light years away. However, Bob is also on the treadmill. On an arbitrary treadmill where different regions move at different stores, it would be possible that Bob is still less than 14 m away. For example if the area near us were moving faster. However, our treadmill (i.e. universe) is actually moving faster the farther away it is. We can calculate therefore that Bob is now actually about 47 m away. So, the way we can know about objects 47 billion light years away is that they were much closer to us when they emitted the photons we're seeing.", "The radius of the sphere that is the cmb/observable universe is 13.8b ly. That makes the diameter 27.6b ly. The things we see that are 13.8b ly away aren't happening live, it's in the *past*. To see those things as they are *today*, we would have to wait 46.5b years because space is expanding/increasing the distance between us. Greater distance being traveled means longer wait. The radius of the sphere that is the cmb/observable universe that will allow us to see those things as they are right *now* will be 46.5b ly. That makes the diameter 93b ly. I used [this]( URL_1 ) for radius to diameter calculation. Scientists use [Hubbles Law]( URL_0 ) to calculate expansion, it's tricky but sharing in case you're interested.", "The universe is expanding, so while we may see light from 13+ billion years ago, the galaxies we are seeing it from have moved away from us a greater distance than that. We know this due to the Doppler effect on the light from those galaxies", "So what\u2019s the current theory of what\u2019s outside this? Just empty space?", "This will sound weird and also a bit off topic, but for an audiobookI had the idea of a ship that could 'move' space instead of itself movinh through it, how impossible is this really?", "What is at the edge of the universe?", "How do we know that that light is 13billion yrs old? I know Im stupid.", "What the top comment said, to simplify it when we are looking at stars we are basically looking back in time"], "text_urls": [[], [], ["https://en.m.wikipedia.org/wiki/Hubble%27s_law", "https://www.omnicalculator.com/math/circumference"], [], [], [], [], [], []], "score": [1435, 42, 14, 11, 9, 8, 5, 3, 3]}}, {"q_id": "7248ig", "category": "Repost", "title": "How did our ancestors deal with deteriorating eyesight without glasses/contact lenses?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dnfmid7", "dnfmelx", "dnfn4h8", "dnfmnz9", "dnfp5ne", "dnfqq5d"], "text": ["You could do a lot of what needed to be done with deteriorating eyesight. Plowing, harvesting, cooking, cleaning, etc. don't really require great eyesight. Things like sewing and carpentry might be harder, but managing a household or a business would be a team effort most of the time and you could shift those tasks to someone with better vision. Note also that there'd be fewer people with failing vision due to Type 2 diabetes, which is so common now.", "I think it didn't matter as much back then...sharp eyesight isn't really important when you can't read.", "The reason wearing glasses is associated with being smart, is because in olden days only people who were able to read would need them, since most other jobs were physical labour where 20/20 vision was not required.", "It really didn't matter. If you don't know how to read and you're not spending your life working in a factory, working on small parts, having blurry vision isn't that big of a deal - as long as you see well enough to not get eaten by a bear, you're doing OK.", "There are accounts of chinese sleeping with small weighted bags on their eyelids to impart a temporary deformation of the eye and some correction, though imprecise. Anyone got any links?", "First off, not all myopia is detrimental. I have 20/25 vision and I don't need correction at all. In fact, my optometrist says that is beneficial with the amount of work I do on the computer. However, you're probably referring to myopia where correction would be beneficial, in not necessary. That severe of myopia was very uncommon before the last 100 years or so. In fact, it's so much more common today that it is considered a modern epidemic. [This video] ( URL_0 ) does an excellent job of going through the evidence. Basically, it's not computer screens or time spent reading that causes nearsightedness. It's spending *too little* time outside. Your eyes need exposure to seeing long distances in the sun to counteract the time you spend viewing objects up close."], "text_urls": [[], [], [], [], [], ["https://youtu.be/qwQzTKHIkb4"]], "score": [49, 40, 19, 11, 5, 5]}}, {"q_id": "725o5a", "category": "Repost", "title": "Why does 0! equal 1?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dnfwtxr", "dnfwnoo", "dnfx8st"], "text": ["Sometimes working with 0 and/or infinity in mathematics boils down to asking questions like, \"Which way of looking at this is the most consistent with what we've done with non-zero values? Of the values that might make sense here, which one breaks the fewest rules?\" One of the arguments for 0!=1 is based on the fact that n! represents the number of ways you can arrange *n* objects in a row or in a line/queue. There are 24 ways I can put 4 coins in a row on a table top, 6 ways I can put three coins in a row, two ways I can put two coins in a row, one way I can put one coin in a row, and the only way to represent zero coins in a row is to remove all coins from the table. Since that's the only representation of 0 coins in a row, 0!=1. Edit: recommended YouTube videos: [Matt meets Jordan Ellenberg]( URL_1 ) (deals with a different question, but still makes good points about how we approach hard math questions) and Numberphile's [zero factorial]( URL_0 )", "It is defined to be that for consistency. There are a number of reasons for that. For example, for any factorial of a number n, we can write n! = n*(n-1)! And if we set n = 1 we get 1! = 1*0! therefore 1! = 0! = 1 Another reason is that a factorial expresses the amount of combinations that can be made of a set of n objects. If I have 2 objects (like a red and blue ball) I can arrange them 2 distinct ways: {red, blue} and {blue, red}. If I have just 1 red ball I have 1 arrangement {red}. If I have no balls (lol) then I only have 1 arrangement: { } which is just having nothing.", "n! is the number of different orders you can arrange n items in. 1! = 1 { red } - > red 2! = 2 { red, blue} - > red, blue; blue, red 3! = 6 { red, blue, green} - > red, blue, green; red, green, blue; blue, red, green; blue, green, red; green, red, blue; green, blue, red There is only one way you arrange a set with no items in it, so it makes sense to define 0! = 1. It also makes other math using factorials work out better."], "text_urls": [["http://m.youtube.com/watch?v=Mfk_L4Nx2ZI", "http://m.youtube.com/watch?v=rT1sIVqonE8"], [], []], "score": [28, 10, 4]}}, {"q_id": "7285za", "category": "Repost", "title": "Movie Volume - Action scenes VS dialogue", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dnglj4k"], "text": ["It's more of a side effect when converting from surround sound to stereo. Because surround has 7 speakers around you, each one requires less volume to make a large total sound. When you compress these 7 speakers into 2 for stereo, the action sequences that use all 7 speakers normally, get compressed into two speakers and are made very loud. While the dialogue scenes with only 2 speakers being used initially, are not compressed so they are at their initial volume which is very quiet compared to the action scenes."], "text_urls": [[]], "score": [3]}}, {"q_id": "72alpf", "category": "Repost", "title": "How can someone have an artery cut and bleed to death within minutes, but someone loses a limb and they can survive for a considerable amount of time?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dnh2woo"], "text": ["Well, if a limb was completely severed, the person probably would die quickly. The reason we hear about soldiers in the middle east getting hit with an IED and surviving, but loosing a limb is because of field medics and a wonderful thing called tourniquets. If a limb is completely removed, the arteries and veins will obviously be severed, too. This of course means that if the body cannot shunt the blood from the extremity, the person will go unconscious very quickly and ultimately die. If you were to puncture an artery in your leg but someone applied a tourniquet quickly, you'd most likely survive it."], "text_urls": [[]], "score": [32]}}, {"q_id": "72asky", "category": "Repost", "title": "Why do dentists tell us to not brush too hard to protect the Enamel, but they take sharp tiny hooks and scrape your teeth with it.", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dnh3zk5", "dnh6256"], "text": ["IANAD but I was told that you can't really brush off the enamel. It's more to prevent gum damage from over-scrubbing.", "In addition to what others have stated, you also (should) brush your teeth twice a day, whereas they use their metal tools maybe twice a year on you. (Though it is mostly because hard brushing causes damage to the gums, while the tools are used on the teeth and don't scrape your gums.)"], "text_urls": [[], []], "score": [8, 4]}}, {"q_id": "72awjn", "category": "Repost", "title": "What actually happens during brain-freeze?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dnh4otf"], "text": ["Nerve endings in your mouth become cold and numb and the heat from your body warming them up causes the pain in your head."], "text_urls": [[]], "score": [7]}}, {"q_id": "72b829", "category": "Repost", "title": "How do we know that the speed of light is the fastest possible speed?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dnh6ipp", "dnh6qa6"], "text": ["It's not that the speed of light is the maximum. It's that there has to be a maximum speed for our physics math to work out correctly (and thereby describe the results of experiments correctly that we can check). Light just moves at this maximum speed, because light doesn't have mass. If the maximum speed would be different, light would move at that speed instead. Light doesn't dictate the speed, it follows it.", "It's nothing to do with light. It's simply that our universe appears to be constructed in such a way that the fastest two objects can change position relative to each other is that speed. That's difficult to get your head around, but it's best way scientists have of explaining some very odd things about the universe. In particular, some scientists trying to measure the speed of light got some very weird results, and at first thought their experiments had gone wrong. But then Einstein gave scientists a theory that would make sense of those experiments. His theories also made sense of the way the planet Mercury moves, which isn't *exactly* how Newtonian theories predict. Einstein's theory made some predictions of its own, which could be tested. For example, if you had two atomic clocks, took one of them up in a very fast jet fighter and flew it around at high speeds for a while, the prediction was that the clocks should then be very slightly out of sync. So that experiment was conducted, and the prediction was confirmed (it's a phenomenon called \"time dilation\"). Einstein also predicted that gravity would affect light, while Newton's theories predicted that it wouldn't. Einstein's prediction was proved correct when scientists carefully observed a solar eclipse and were able to see a star that in a Newtonian universe should have been hidden, proving that the sun's gravity had very slightly bent the light from that star. As long as experiments and observations continue to support Einstein's theories, those theories will continue to hold water. You cannot make any two objects in the universe move towards or away from each other at more than the speed of light."], "text_urls": [[], []], "score": [21, 8]}}, {"q_id": "72fjph", "category": "Repost", "title": "What exactly is a game \"engine\" and what is its purpose?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dni48iq", "dni4nbd", "dni5z0i"], "text": ["Things you care about as a game designer: the plot, the art, how the graphics look, the music. Things you don't care about: how the graphics are rendered, how input from the keyboard gets to your system, etc. The engine, ideally, gives you a nice and simple interface to access common game functionality, without making you care too much about the details of it. Pretend you're taking a road trip. You want to look up the route and some cool places to eat or sights to see. You don't want to have to care about how the gears in your transmission work, or whether the ECU in the engine is supplying enough fuel.", "When you're programming a game, there are a huge number of things that have to be taken into account - especially in modern games. There are of course the very obvious things - the characters look like this, the main character's health regenerates that fast, this gun shoots x bullets per second and does y damage, etc. But along with that there's a lot of stuff that's more \"under the hood.\" How do objects interact with gravity and other physical forces when they hit a wall, or roll down a hill? Where is the light source, and how does it reflect and scatter off of a lake? How does the computer or console actually take a button input and transfer it into a game action, how does it render textures, how does it generate the world and populate it with characters when you load up the game? The game engine is what handles most or all of that \"under the hood\" stuff. And many games start with an already-made engine (like the Unreal series) because it saves a *huge* amount of time and cost that would come from building and testing a brand-new engine. With that as a starting point, they can make changes to it as they see fit and add the details of their game of top of it. Dishonored 2 used a heavily modified version of an engine called ed Tech 5 - so they started with that and made lots of customizations to it. Since they changed it so much, they decided to name their version of the engine, and so they named it something that was significant to their project, \"Void.\"", "I won't repeat the other posters here but I will use an analogy. A game engine for creating a game is similar to Photoshop for creating/editing an image. Without Photoshop (or similar software) perhaps you want to increase the contrast of the photo... well you would have to literally go through all the pixels and slightly modify their numerical color values and it would take a really, really long time. Photoshop knows that this is a common thing that people want to do, so it has a simple button that you can click, drag, whatever to perform this action in seconds. A game engine, like other types of software, is essentially just a large collection of things that game developers might want to do that are pre-programmed so they can be done easily and quickly rather than painstakingly from the ground up. Sometimes developers build an entirely new game engine from scratch, and usually that is because they want to do things that no other game has done before and therefore no existing game engine has it pre-programmed in."], "text_urls": [[], [], []], "score": [9, 5, 3]}}, {"q_id": "72ftkb", "category": "Repost", "title": "If I only get three hours of sleep over night but take a four hour nap is it like I got a full nights sleep?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dni7gva", "dni7sya"], "text": ["Most likely, yes. Your sleep cycle is divided into parts like deep sleep and REM, and you go through several such cycles every night during a normal eight-hour rest. Now, if your three-hour rest was interrupted halfway through a cycle, that can be very disruptive. But as long as you are able to get a high quality of sleep for your nap you should be fine. Disclaimer: I am not a sleep doctor and wouldn't make a habit of it, because a four-hour nap is likely to be lower-quality sleep than what you really need. But once in a great while won't do too much harm.", "There are different types of sleep cycles. What you are describing is similar to a biphasal sleep cycle where you break your sleep up into multiple parts. Throughout college I lived on a sleep cycle of four hours at night and 2 in the afternoon. By breaking up your sleep you don't need as much overall."], "text_urls": [[], []], "score": [5, 3]}}, {"q_id": "72hdqi", "category": "Repost", "title": "If Nazis were socialist, why are they considered far right and not far left?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dnijs2o", "dnijz3d", "dnijp93", "dnik6uq", "dnijis6"], "text": ["**Nazis were not socialists**, anyone who tells you otherwise is either lying or stupid. They had \"socialist\" in their name but there was nothing socialist about their ideals - it was just a holdover from the popularity of socialism among the working classes when they started out -like how the Democratic People's Republic of Korea (North Korea) is not at all a democracy. The Nazis *hated* socialists and communists and killed them in the Holocaust. [This guy says pretty much the same thing]( URL_0 ).", "While the Nazis did get support by promising to use the power of government to end the miserable suffering that many Germans experienced after WWI, that was about the limit of similarities with Marxist socialism. The biggest difference is that Marxist socialism seeks to abolish elite control over the means of production while Nazi national socialism sought to make party-loyal Germans the elite class.", "They weren't really socialists. The way they used the term \"Socialism\" differs quite a lot from any other use of the word. They were pretty much trying to re-define the term completely, into their ideology. Socialism as a term was fairly popular at the time, and they made use of that popularity.", "Pimarily because of their 1.) Racist ideologies, and 2.) Elitist social structure Both of which are counter to socialist theory. Never underestimate people's ability to ignore the obvious, especially when they're being ordered to ignore the obvious....", "They were not actually socialist. Nazis actually seen socialists as a threat, and hated communists more than red scare era America. They called themselves socialists in an attempt to draw the workers vote."], "text_urls": [["https://www.indy100.com/article/nazi-socialist-right-wing-white-supremacists-history-twitter-mikestuchbery-7900001"], [], [], [], []], "score": [39, 10, 8, 5, 4]}}, {"q_id": "72igi9", "category": "Repost", "title": "What is the difference between strategy and tactics?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dnisjd3", "dnisf68", "dnis5aq", "dniss4n", "dnitqdo", "dnisk3o"], "text": ["A strategy is a plan, a tactic is an action. In battle terms, your strategy to defeat a town might be to starve them out, and your tactics would be blocking their supply lines or spoiling their food stores. That being said, I think that they're basically interchangeable in everyday language. There might be an implication that a 'tactical' decision is something done in-the-moment to achieve immediate ends, while a 'strategic' decision is part of a longer-term plan.", "Google says \"Tactics are the actual means used to gain an objective, while strategy is the overall campaign plan, which may involve complex operational patterns, activity, and decision-making that govern tactical execution.\" Winning the battle relies on tactics. Losing the battle to win the war is a strategy.", "In Chess, a strategy is a long-term goal and tactics are short-term solutions to positional problems. If we extrapolate from there, a strategic decision is a plan to move forward toward a specific goal, whereas a tactical decision is a quick-fix in order to correct for issues that arise during your strategy.", "Tactics = small scale. (Action to make the Strategy work). Strategy = large scale. (The over all plan). Your strategy is to use certain tactics/methods to gain 1 up on others in the long run, that being in sports, business or war. Its ofcouse alot deeper than that, but the short of it is that your over all plan is strategic and you use tactics to reach that goal.", "An interesting word is the (relatively uncommon) ***stratagem***. > **Stratagem** and **strategy** are sometimes interchangeable, but they are usually not synonyms. The more common **strategy** is broader. Its main definitions are (1) *a plan of action intended to accomplish a specific goal*, and (2) *the art or skill of using plans or stratagems, especially in war*. **Stratagem** is sometimes synonymous with **strategy** in military contexts, but its primary definition is a clever scheme for achieving an objective, often by deceiving an enemy. So while **strategy** can denote any plan of action, **stratagem** usually implies subterfuge or unconventional tactics. > Both words go back to the Greek **strategos**, meaning 'general' (the high-ranking military official, not the adjective), but **stratagem** came directly from the Old French **stratageme**, and **strategy** is a newer (19th-century) adaptation of the ancient word. Note that **stratagem** is spelled with two a\u2018s rather than two e\u2018s. The misspelling 'strategem' is common. [Source]( URL_0 )", "Taking her on a date is a strategy. Busting loose with those hawt Saturday Night Fever moves is a tactic."], "text_urls": [[], [], [], [], ["http://grammarist.com/usage/strategy-stratagem/"], []], "score": [34, 6, 6, 4, 4, 3]}}, {"q_id": "72j4wl", "category": "Repost", "title": "Why is it so hard to cure cancer?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dnixwrp"], "text": ["Cancer is not really a thing by itself like say a virus, it is the name we give to your own body's cells going wrong in a particular way, ie, multiplying out of control. There's around 200 different types of cell in your body, and each can go wrong in many different ways that lead to cancer, so there are literally hundreds of separate things-gone-wrong that we call by the one label cancer. As the cells are your own, it is difficult for your immune system to know to try to kill them, and difficult for us to kill just the gone-wrong cells whilst leaving the healthy cells alive."], "text_urls": [[]], "score": [6]}}, {"q_id": "72n71b", "category": "Repost", "title": "Why is 10 degrees celsius not exactly twice as warm as 5 degrees celsius?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dnjrn41", "dnjrtxl", "dnjrw76"], "text": ["Because 0c is not the lowest possible temperature. If you use the Kelvin scale, which starts at absolute 0, then 10k (-263c) is twice as hot as 5k (-268c).", "Yarr! Yer not alone in askin', and kind strangers have explained: 1. [ELI5: Why is 50 degrees Fahrenheit not twice as hot as 25 degrees Fahrenheit? ]( URL_2 ) 1. [ELI5: When cooking food, why doesn't doubling the temperture, reduce the cook time by a half? ]( URL_0 ) 1. [ELI5: Why is it meaningless to say if it is 20 degrees oC, that it is twice as hot as if it was 10 degrees oC? ]( URL_1 ) 1. [ELI5:Why is cooking in an oven at 150 degrees for 20 minutes not proportional to 300 degrees over 10 minutes? ]( URL_3 )", "Because 0 degrees Celsius isn't the absolute zero, it's just the temperature of fusion of ice. If you compare to the absolute zero of -273.15 degrees celsius. 10 degrees is 283.15 and 5 degress is 278.15. So 10 degrees is 5/278.15 or 1.8% more warm in term of temperature. But not in term of energy because different material need more of less energy to change temperature of change phase."], "text_urls": [[], ["https://www.reddit.com/r/explainlikeimfive/comments/28atax/eli5_when_cooking_food_why_doesnt_doubling_the/", "https://www.reddit.com/r/explainlikeimfive/comments/1rwm6e/eli5_why_is_it_meaningless_to_say_if_it_is_20/", "https://www.reddit.com/r/explainlikeimfive/comments/3v745x/eli5_why_is_50_degrees_fahrenheit_not_twice_as/", "https://www.reddit.com/r/explainlikeimfive/comments/34o21l/eli5why_is_cooking_in_an_oven_at_150_degrees_for/"], []], "score": [18, 5, 3]}}, {"q_id": "72pc0z", "category": "Repost", "title": "If the primary colors are red, yellow and blue. Why do screens use red, green and blue?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dnk9irq"], "text": ["There are 2 color systems, additive and substractive. In the additive system, mixing the colors together makes white. This is why screens use red, green and blue. In the substractive system, mixing the colors together makes black. Red, blue and yellow are the colors that are taught in elementary school. The real colors are cyan, magenta and yellow. These are the colors used in your inkjet printer."], "text_urls": [[]], "score": [3]}}, {"q_id": "72rmhi", "category": "Repost", "title": "What are imaginary and complex numbers?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dnkprjb", "dnkoq9h"], "text": ["Think about an algebra problem involving an unknown quantity x. As far as arithmetic is concerned, you know x behaves just like any other number. So 1-3x+8x-9 = -8+5x. 2x \u00d7(4x-3) = 8x^2 -6x. Now let's bring in another rule, that we know x^2 = -1. No real number (the usual numbers, including fractions and irrationals like pi) satisfies this. But, for fun, let's pretend. Then we know that 8x^2 - 6x = -8-6x. in fact, any arithmetic expression will end up of the form a+bx for real numbers a and b. E.g. for a longer expression 8x^6 -4x^3 (2x -1) = 8(-1)(-1)(-1) -4x(-1)(2x-1) =-8 +4x (2x-1) = -8+8x^2 - 4x = -16-4x. So, by inventing an \"imaginary\" variable x (usually denoted i by mathematicians and j by engineers), we get a new arithmetic system for numbers of the form a+bx, or in more common notation, a+bi.", "A complex number is a number of the form a + bi, where a and b are real numbers and i is the imaginary unit, satisfying i2 = \u22121. For example, \u22123.5 + 2i is a complex number. The real number a is called the real part of the complex number a + bi; the real number b is called the imaginary part of a + bi."], "text_urls": [[], []], "score": [4, 3]}}, {"q_id": "72u7n6", "category": "Repost", "title": "Do the cells (or whatever constitutes your) bones regenerate every 7 years as with the rest of your body or not? If not, why not?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dnl9y1c"], "text": ["your bones are not made of cells, they're made of minerals,fibers, and protein with many spaces and surfaces occupied by cells. Bones are continuously being dissolved and rebuilt on a microscopic scale, even when there is no significant injury or active growth."], "text_urls": [[]], "score": [3]}}, {"q_id": "72x8kg", "category": "Repost", "title": "What makes a high-priced lawyer for a big company or rich individual \"better\" than a non high-priced lawyer if the laws and precedents are the same and all other factors being equal?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dnlz3cj", "dnm3ghz"], "text": ["Having the resources and knowledge to construct sound legal arguments based on the existing statutes and precedents is not something anyone with a JD can do just as well as anyone else with a JD. This is like asking why a high priced surgeon is better than a low price one when your organs and the problem are the same either way.", "Let's boil a lawyer's job down to three main jobs as relate to the client. They write arguments/briefs/documents, they organize/execute research projects, and they negotiate with other people on the clients behalf. Arguably, the research component of this \"should\" come out the same no matter the lawyer---the law should be there to be found, after all, and all sides should be looking for it. But, from the other two components of a lawyer's work it's clear from other similar jobs that there can be differences in quality. There are certainly people who are better writers than others, people who are better at convincing/acting than others, and---i'd say---that even with the third component there is definitely a skill to organizing research effectively and efficiently. Now, that doesn't mean a higher paid lawyer is always better than a less well paid one, but just like it usually costs more to hire, say, Stephen King to write your screenplay than me, or more to higher a PHD to run your lab than a grad student, or more to hire Tom Cruise to give your big speech than, well, me, so to do people pay more for \"better\" lawyers."], "text_urls": [[], []], "score": [12, 3]}}, {"q_id": "72yr1b", "category": "Repost", "title": "How does a piece of ceramic spark plug break a car window so easily?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dnm9t10", "dnmajq0"], "text": ["Car windows is made from tempered glass. While tempered glass is super good at withstanding breaking. Tempered glass has extremely high surface compression and generally high stress, which makes it harder to break. Ceramic spark plugs is made of aluminium oxide ceramic. When aluminium oxide breaks, it becomes very, *very* sharp. So sharp that it sort of \"punctures\" the window, which makes the stress of the window shatter it into tiny pieces.", "First let's talk about the glass on a car. Most of the windows (except the windshield) are made from tempered glass. Tempered glass is known for being quite strong, but also fails quite spectacularly, instantaneously shattering into an enormous amount of little pieces. Why does it do this? Well let's understand the processing. This glass is cooled rapidly from liquid to solid. Glass that cools more quickly ultimately ends up at a lower density, hence a higher volume compared to glass that cools slowly. graph Well guess what, there is a thermal gradient in a pane of glass as it cools. Meaning the outside rapidly cools and the inside does not. This puts the outside of the glass in compression and in the inside in tension. This acts as a crack inhibition method, meaning that the stress necessary to propagate the crack must first overcome the compressive stress on the outside (since glass will fail in tension well before compression). So what do we get? A glass that is ultimately very strong, but has a massive amount of stored internal energy through the tempering process. Stress Profile in Tempered Glass Let's say we want to break this glass though. How do we go about it? Well if we can force a crack to propagate through this thin compressive stress layer on the outside and into the stored tensile stress region, then this crack will immediately cause catastrophic failure. The easiest way to do it? Use something small and hard to act as a stress concentrator. This can amplify the force applied and help penetrate this region. So in the case of the spark plug shard, which is made from a hard ceramic (likely an alumina based material) the impact from the ceramic is enough to form a crack and cause it to penetrate the glass deep enough. That is also why you can buy punches (firefighters and other emergency responders also carry these) that are essentially hardened steel or diamond tipped and do the same thing. Hardness of the glass compared to to impact material is definitely relevant since this interaction is very similar to a hardness test (Rockwell, Vickers, Knoop, etc. Indent tests). The material needs to be harder, or at least close to the same hardness as the glass. I highly discourage people from using the Mohs scale to get actual numbers. Sources: Shelby, \"Introduction to Glass Science and Techonology\" Varshneya, \"Fundamentals of Inorganic Glasses\" Fun fact: your windshield is engineered to break before a human skull will. [Here is an interesting study]( URL_1 ) talking about injuries associated with laminated vs. tempered glass in auto collisions. [Source]( URL_0 ) credit u/HateCranker"], "text_urls": [[], ["https://www.reddit.com/r/askscience/comments/2w7ken/why_does_a_piece_of_a_sparkplug_work_so_well_at/coog9fs/?utm_content=permalink&amp;utm_medium=front&amp;utm_source=reddit&amp;utm_name=askscience", "http://www-nrd.nhtsa.dot.gov/pdf/esv/esv20/07-0101-W.pdf"]], "score": [16, 10]}}, {"q_id": "730sj0", "category": "Repost", "title": "How do unions work?", "title_urls": {"url": []}, "selftext": "I understand their purpose, I just don't get how they go about achieving that purpose.", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dnmq14l"], "text": ["The basic idea behind a union, is that an individual employee has very little power against the company, but all of the employees rallied together have power. The concept is called collective bargaining. So instead of each employee talking to their manager individually, and having wildly different requests, the employees get together, agree on a few things they want, and then talk to the employer as a group. Unions tend to work in cycles. As employers gain power, they want to do things like increase profits, which usually means lowering costs and increasing output, which sometimes means bad things for workers (like making them work longer days). At some point, the workers get together, form a union, and fight back against the employer to improve their conditions. Then, once the power has shifted back to them, the union atrophies and becomes unnecessary or starts fighting for silly things, so it dissolves. Being able to form a union is incredibly important for our society, because the employer having all the power long term tends to be bad news for the common worker. In societies where forming a union is illegal, it tends to be very oppressive."], "text_urls": [[]], "score": [4]}}, {"q_id": "7353vu", "category": "Repost", "title": "why is a keyboard set up the way that it is? Are the order of the letters for a specific reason?", "title_urls": {"url": []}, "selftext": "Is this something I should have learned when I was 5, hammering away on my first computer back in 98? Apologies if I'm just being dumb.", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dnnoj2r", "dnnok1z"], "text": ["Ohhh I know this one!! It has to do with the sequential use of keys when typing on a typewriter. If the keyboard is set up differently, you have a higher chance of the arms with the letter stamp hitting each other or getting jammed together.", "I think it was arranged that way because it kept common pairs of letters way from each other. Old typewriters would jam when two striking arms (not sure what they are called) close together would move at the same time."], "text_urls": [[], []], "score": [12, 3]}}, {"q_id": "7358xd", "category": "Repost", "title": "What exactly is the point of a tax return?", "title_urls": {"url": []}, "selftext": "I recently got my first job and my manager told me i\u2019d have to file taxes but along with that comes a tax return. I\u2019m in school still so i\u2019ve never actually learned or really even talked about taxes with anybody, so from my limited understanding, i pay into like social security, medicare, and federal/state taxes and then i get all that money back in the form of a tax return. So what exactly is the point of even paying that money in the first place if i\u2019m just gonna get it back in the end?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dnnrnkj", "dnnpyse", "dnnq4v3", "dnnt3wz", "dnnrb1p"], "text": ["The American system of taxation, in 25 words or less, is: * Add up everything you made **from all sources**; calculate the tax on it. * Add up everything you prepaid **from all sources**; resolve the difference. Pretty simple, really. ----- Next, although all those things you mention ARE \"taxes\", you'll have a better understanding of the system if you keep them separate: * **Federal income** tax is graduated, so some of your income is taxed at 0%, some is taxed at 10%, still more is taxed at 15%, then 25%, then 28%, and so on. * **State income** tax is sometimes graduated, sometimes flat-rate, for example a straight 4.25% on everything you make. Depends on each state -- and some states don't tax **income** at all. * **Social Security** tax is a flat 6.20% on every dollar up to ~$118K; then it stops. * **Medicare** tax is a flat 1.45% on every dollar, with no limit. These taxes are withheld from your paycheck each week or month, because the government has bills to pay each week and each month. If you overpay, you get the excess refunded to you. If you don't pay enough, you pay the balance due when you file your return. ----- Memorize this: *\"I file a* ***return*** *to get my* ***refund*** *\".* The tax return is the form you file. The refund is the money you get back. Don't misuse those terms. ----- > So what exactly is the point of even paying that money in the first place if i\u2019m just gonna get it back in the end? If you are **absolutely certain** that you won't have ANY income tax liability at the end of the year, then you fill out your W-4 form to say so, and you **won't** have any Federal Income Tax withheld. The other taxes, though, are still due. Does that help?", "The way the tax system works is that you have to pay a certain amount of taxes for every dollar you earn. Unfortunately, because some people work multiple jobs, switch jobs mid-year, or other reasons, the employers don't know whether they are giving you the 10,000th dollar or the 20,000th. For the employers, it is easier to make some minor assumptions and take what is likely a little too much from your return. At the end of the year, you combine the W-2 forms from all your jobs and report to the IRS what you made, and the difference is returned to you. The only real alternative is to not take any income taxes from your paycheck at all, which means each person would have to set money aside (not an easy feat for people living paycheck to paycheck) so they can pay the taxman at the end of the year.", "First off a tax return are the forms you file in April. A tax REFUND is money you get back. Whether you get money back and how much depends on a variety of factors, such as total income, what deductions you have, etc. You personally might get it all back if you're only working part time or part of the year, and have school expenses like tuition you can deduct. Somebody else making the same hourly as you do might not get a refund (or a small one) if they work the whole year, have a spouse also working and they make a fair amount of money, or could even owe more money if they have other forms of income (like investment income, side gig/freelance).", "Common mistake people make: Your *Tax Return* is the form you file with the government at the end of the year to figure out if you over or underpaid for the year. If you overpaid, the money you get back is your *Tax Refund*.", "It's a weird system. The basic idea is that all workers have some money taken off each paycheck to ensure that typical people don't find themselves at the end of the year owing way more taxes than they can pay. Because the amount of tax people owe can depend on a lot of tricky stuff, it's often not exactly the right amount. Any difference between what's taken off over the year and what's owed is determined by the tax return. Ideally, tax returns are just about fairly minor accounting corrections, such that your tax refund is a small percent of what you've paid. (I once got an $8 tax refund.) It also provides a way for tax credits to be applied, especially the Earned Income Tax Credit, which is a pretty big part of the welfare system. Tax refunds are popular mostly because they look like free money. On paper, it would be better to have no tax refund and get a little more money each month that you can use, but for people who have trouble reliably saving money it can help out. The details of how much gets taken off depend on how you fill out the form W-4. If you owed no tax last year and don't expect to owe any this year (which is true of a lot of students with a summer job) you can be exempt from withholding. There's a calculator for this: URL_0"], "text_urls": [[], [], [], [], ["https://www.irs.gov/individuals/irs-withholding-calculator"]], "score": [20, 8, 4, 3, 3]}}, {"q_id": "73dkqk", "category": "Repost", "title": "How do underwater cables like the ones across the Atlantic Ocean work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dnpjo2d", "dnpk8oc"], "text": ["First, they use the most efficient medium possible. For telecommunications, that means fiber optics. These cables are specially designed to withstand the pressures of being undersea and preventing seawater from entering them. These cables carry signals using a technology known as Dense Wavelength Division Multiplexing (DWDM) - in plain English, they stuff a bunch of channels into the optimal transmission band. Now, DWDM is great for getting a lot of bandwidth, but it doesn't inherently have trans-oceanic reach. So, in the center of the cable is a high voltage cable that can be used to power equipment that gets put in the ocean as well. Because undersea work is super expensive and they want to minimize the amount of stuff that might break, companies want to minimize the amount of equipment that gets buried. The end result is that they use two types of high-power amplifiers (EDFA and Raman) that can be paired together to get up to 400 kilometers between amplifier sites. The company building the cable figures out where the cables are going to connect to the land-based networks, and then plot out a course across the ocean. In shallower areas near shore, the cable gets buried using plows so that a ship can't accidentally cut the cable by dropping an anchor on it or something. As you get farther out to sea where those kinds of events become veeeeeery unlikely, the cable is laid across flat parts of the ocean. The amplifiers get connected as needed, and eventually everything gets connected up and you have a link across the ocean. (It's obviously more complex than that, but that's the general gist of it).", "URL_0 From the submarine cable Wikipedia page. Check out \"submarine cable cross section\" pictures too. I think they're really cool looking."], "text_urls": [[], ["https://i.imgur.com/4lx0wPi.jpg"]], "score": [17, 3]}}, {"q_id": "73hazg", "category": "Repost", "title": "How could anything have \"happened\" to cause the big bang if time and space did not exist before the big bang?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dnq9u04", "dnq9ubj"], "text": ["That is a great question. Unfortunately - through no fault of your own - it doesn't actually make sense. Our models don't go back far enough. Get even too *close* to the actual big bang - let alone *before* it - and time itself ceases to make sense. Under the models that we have available, it is *literally impossible* to draw meaningful conclusions about the Planck era beyond some very broad, very vague generalities.", "There is a theory that this universe we live in is not the first universe. Every Big Bang has given birth to a universe and after a very very long long time eventually collapsing again. There is no way to be sure that something didn't cause the Big Bang that created our universe... I prefer Douglas Adams to explain this one: \u201cThere is a theory which states that if ever anyone discovers exactly what the Universe is for and why it is here, it will instantly disappear and be replaced by something even more bizarre and inexplicable. There is another theory which states that this has already happened.\u201d"], "text_urls": [[], []], "score": [13, 7]}}, {"q_id": "7ncnjf", "category": "Repost", "title": "What causes the audible electric 'buzzing' sound from high voltage power lines?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ds0ymly", "ds184ur", "ds10oq5", "ds16a58", "ds11c55", "ds19a2v", "ds18a8z", "ds1fy88", "ds1a8mr", "ds1csdt"], "text": ["It's oxygen molecules being charged with electricity. When the charged particles give back that energy they emit light and with a high enough charge the energy transformation of these particles can also be heard as a buzzing sound. The extreme example would be lightning - particles charged up to a million volt that will make a big boom when discharging, that is the thunder you will hear accompanying the lightning bolt.", "The sound you're likely hearing is partial discharge or corona discharge, not the sound of the frequency of the electricity (unless you're listening to a transformer). It's the noise that air makes as electricity jumps through it, basically baby lightning, for power companies this is a problem for polymer and oil based insulation (ceramics don't mind) as it degrades their ability to resist the voltage. You can't hear this on low voltage since there isn't enough 'pressure' on the electricity, you could however hear the frequency of the electricity in something like a microwave transformer or a electric motor that is stalled. The higher the voltage, more humid and if there is a sharp point can all make it louder, so have a listen to it on a humid night and you might even see it.", "I\u2019m pretty drunk but I think it\u2019s sudceptance! The negligible flow of charge across insulators and air! If it weren\u2019t so small it would be a mother f\u2019er for engineers to calculate as it\u2019s very temperature, humidity, and site (type of Insulator) specific. That humming is called \u201ccorona\u201d because it actually glows like a crown at night. Well very faint. I\u2019m probably wrong.", "People are talking about frequency and current and it's too abstract for an ELI5 answer. If you slow down the buzzing, it sounds like a spark. If you've ever heard static electricity sparking and repeat that faster and faster, it turns into that buzzing sound.", "As others mentioned, the AC power is alternating at 60 cycles per second. This creates a magnetic field that interacts with the metal of the conductor, and metal bits near the conductor, causing them to vibrate and slightly change shape at that same rate. This vibrates the surrounding air at the same rate, which is within our range of hearing. Beyond my understanding and the scope of an ELI5, you are probably hearing not only 60 Hz but also harmonics of that, which would explain the sizzle on some high voltage lines. A pure 60 Hz tone would be a quite low bass note. Also, on very high voltage transmission lines, ionization of the surrounding air may contribute to the sound, but that is beyond me and just a guess.", "Oxygen is being ionised by the high voltage. This also leads to voilet light formations. It is called Corona Discharge.", "Ionisation of air due to the high voltage electric field. Corona effect. Not due to magnetic field which does other things.", "Finally a thing I know about! The buzzing from high voltage power line is known as corona, it's essentially the high voltage ionizing the air in certain areas around the line. Usually corona will happen when there's a corner or sharp edge on the power line so spacers and things are designed to be \"corona free\".", "It's a combination of things : Vibration of metallic parts due to the magnetic field. (think transformers or other parts surrounding the lines). Metal actually changes shape due to the magnetic field changes. Both would act as a loudspeaker. And. Somewhat the result of polarisation in the air like explained here before. It's named the Corona effect. URL_0", "Because the lines use alternating current which creates a magnetic field that switches direction with the current. So if it's 60Hz the magnetic field will switch directions 120 times per second. The Earth has its own magnetic field. When you have a current pass through a material within a magnetic field a force is created due to the interaction. That force causes the wire to vibrate. Typically that vibration isn't strong enough to be audible, but in high voltage wires it is.... Due to the high voltage. Edit: i originally didn't have the correct frequency for magnetic field Thanks to u/wadeeffingwilson for the [Correction] ( URL_0 )"], "text_urls": [[], [], [], [], [], [], [], [], ["https://en.m.wikipedia.org/wiki/Mains_hum"], ["https://www.reddit.com/r/explainlikeimfive/comments/7ncnjf/eli5_what_causes_the_audible_electric_buzzing/ds1ej44"]], "score": [1899, 673, 75, 74, 9, 5, 3, 3, 3, 3]}}, {"q_id": "7ndwgx", "category": "Repost", "title": "how can celebrities and others go on tv/radio/documentaries etc., openly admitting illegal drug use, and not be prosecuted?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ds12x7n", "ds12wk9"], "text": ["they can just say they lied. you'd need to find evidence to actually bring charges. And random recreational drug busts arent really the goal.", "Police and prosecutors have budgets and priorities. Even if you are a huge stickler for drug laws, arresting celebrities who claim to have used drugs is a pretty bad use of resources. Celebrities have money (to mount a good defense) and fans (to get angry with you and apply political pressure)."], "text_urls": [[], []], "score": [6, 3]}}, {"q_id": "7nhi2v", "category": "Repost", "title": "when there is no atmospheric pressure in space, how spaceships push themselves?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ds1suwb"], "text": ["Newtons 3rd law of motion. For every action there is an equal and opposite reaction. They shoot exhaust out the back and the opposite force pushes the vessel forwards. Same reason you can stand on a skateboard and throw a bowling ball backwards to generate forward motion."], "text_urls": [[]], "score": [4]}}, {"q_id": "7ni9h4", "category": "Repost", "title": "Why does everything hurt more when you're cold?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ds1z3xz"], "text": ["The decrease in blood flow to your fingers and toes can cause increased sensitivity to the fingers and toes. As the nerves are densely packed together and are close to the surface of the skin, any cold temperature past a certain threshold is then perceived as increased pain."], "text_urls": [[]], "score": [4]}}, {"q_id": "7nicqq", "category": "Repost", "title": "What is \"subnetting\" and why is it important for network professionals?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ds252re", "ds204yk"], "text": ["The best analogy I can think of is that they are like splitting mail routing by zip code (at least in the US). Just like buildings and homes have addresses, devices have addresses too (IP addresses). A subnet is a specific group of addresses that a particular \"router\" will handle, not unlike a particular post office will serve a specific Zip code. It isn't always practical for one router or one post office to handle a large amount of addresses, so it makes sense to split them up. However, the routers must also know where to send any network traffic that isn't theirs. Just as the local post office will pass all of the mail outside of the zip code to other post offices. Network engineers must design these different subnets and the routing to account for performance, cost, and other concerns. Otherwise the network would be unmanageable.", "In a nutshell, on a given network, there's times you want to segregate certain parts of it. Just as an example, where I work there's a distinction between the part of a network wifi clients land on, the part of the network security hosts are on, the part that connects to our networked filesystems, and the part reserved for infrastructure hosts. Subnetting allows an administrator to make these logical distinctions. Not every host on the network can access every subnet, different subnets are monitored and behave differently, etc."], "text_urls": [[], []], "score": [8, 6]}}, {"q_id": "7njdno", "category": "Repost", "title": "why does simply checking your credit score, lower it?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ds28f8o"], "text": ["Google \u201chard pull\u201d versus \u201csoft pull\u201d When you want to know your credit score - make sure you\u2019re only getting soft pull results. When you get closer to an event like a car purchase or house purchase - you\u2019ll have to do a hard pull at some point - but do your research first so you don\u2019t make things worse!"], "text_urls": [[]], "score": [7]}}, {"q_id": "7nkck2", "category": "Repost", "title": "If we could do a manned landing on the moon in 1969 why has it been so hard to go back? Why have such few countries managed to do it considering how far tech has progressed over the past 50 years?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ds2h19q"], "text": ["We have the technology to build new pyramids, too, but we still haven't replicated the Giza ones. It's an enormously costly endeavor, tech or no."], "text_urls": [[]], "score": [3]}}, {"q_id": "7no3qg", "category": "Repost", "title": "How is milk turned into cheese?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ds37s2r", "ds37i5o"], "text": ["1. Add acid to milk to make it sour. 2. Add rennet (enzymes from the stomachs of certain mammals like cows). 3. This separates the milk into solid curds (solidified milk proteins) and liquid whey (mainly sugars) 4. The curd is then processed. The specifics depend on the cheese being made. Some are ready as is. Some are dried out. Some are heated. Some are stretched. Some are washed. 5. Ripening. The cheese is left to ripen for days to years, allowing microbes and enzymes to perform chemical reactions which change the tasted and texture of the cheese. Some have additional bacteria and molds introduced to enhance this process.", "Rennet, a stomach enzyme from cows and certain other mammals is added to milk. This causes the whey to separate from the curd. The whey is drained off, and the curds are put into molds and pressed. Different cheeses are made in different ways, but that's basically it."], "text_urls": [[], []], "score": [21, 6]}}, {"q_id": "7npcms", "category": "Repost", "title": "If the universe is constantly expanding, what is it expanding into?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ds3hleq", "ds3heof", "ds3hgom", "ds3i86y"], "text": ["Nobody has any idea. Some think it could be more of what we see around us in the observable universe. Some think it could just be some mass of something we can't possibly fathom. Some think of our current universe as sort of a bubble and that other universes exist outside of it in their own little bubbles. It's really just speculation because there's no real way to observe it and know.", "We cannot really know, because all our science is based on the observation, there is no way we can observe something outside the universe, so we cannot really deduct anything scientific about what is 'outside' the universe. There probably does not even exist anything outside the universe, the universe is creating its own space and time as it expands and was probably infinite from the moment of coming into existence.", "It's expanding into itself. Take a balloon, and draw two dots on it. Then blow up the balloon. The 2 dots are further apart from each other now. The space between them has expanded. If we think of the balloon as a 2D plane, and ignore the 3rd dimension, the balloon just looks like it's expanding everywhere, not expanding into anything. Now just add one dimension, and you have our universe.", "Unfortunately, the universe is (as far as we currently can see) everything there is. But there's been expansion, which means there's been more everything to have. A little confusing. Think of the universe as a sheet of grid paper with one line down the middle and across the middle. As time goes on, we add more lines. It takes the same amount of time to cross each square, unfortunately, but the paper remains the same size overall. If you reach the edge of the paper? Well, you might just see more paper. You might end up at the other side of the paper. No one is really sure just yet. (As far as I know, I'd love to hear more.) The paper, is all there is. To think about what's \"outside\" the paper is irrelevant, since what exists is inside the universe. (The outside could be anything if it exists. We cannot exactly pin down the physics on this one. It might be an infinite sea of rubber ducks. A place where time is 3 dimensional. A space baby. Could be a 3 dimensional event horizon to a collapsing 4-dimensional star in a 4 spacially dimensioned universe. Anything is possible.) The thing about this, however, is that objects remain a solid size throughout this. So in the beginning of our paper, all of that stuff was sort of stuck in a very small amount of squares, making it very hot. Almost instantly, the universe gained enough space for things to get a lot less crowded, and stuff started to get a lot more friendly so stuff could happen. Though physics sort of fails on the specifics. (Why didn't it collapse into a black hole if it was basically a singularity? Hmm...) So in short, it's unknowable if an \"outside\" exists, and all we are capable of being aware of at this time is our own visible universe. But we'll have to see where science takes us."], "text_urls": [[], [], [], []], "score": [4, 3, 3, 3]}}, {"q_id": "7ns500", "category": "Repost", "title": "The moon\u2019s gravity can visibly affect tides, but not the water in a glass. Why is this?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ds44f1v", "ds48hzr", "ds497bz"], "text": ["Given how much water is in the ocean, the few feet of tide isn\u2019t really that much at all. If you scaled the ocean down to the size of a cup, the tides would be imperceptible.", "Tides aren't just about the strength of the moon's gravity, it is about the *difference* in its strength. The gravitation pull at the left side of your glass isn't that much different than the right side. But with an ocean, one side can be thousands of miles further from the moon than the other. This *difference* in the pull cause the ocean to warp, which in turn causes the tides.", "Same reason there are no tides on a small lake. The gravity change needs a massive 'bowl' for the effect to be noticeable. Tides are just the water sloshing around the world due to the changing pull of gravity. The moon pulls water a little closer to it. 5 feet of tides in an ocean that is thousands of feet deep isn't all that much. Now, the gravity at one end of a pond from the moon is basically the same at the other end because they are so close. Same as in your cup. The moon is 3 inches further away from one end of the cup than the other. Vs 25,000 miles for the earth. TL;dr: Much bigger volume in the ocean and much bigger difference in the distance between one side of the ocean and the other to the moon."], "text_urls": [[], [], []], "score": [13, 8, 4]}}, {"q_id": "7ns7m1", "category": "Repost", "title": "Do our eyes have frame rates? why do things get blurry when they are moving fast enough?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ds44v8s", "ds44sh8"], "text": ["No, your eyes do not have a frame rate. They work on analog signals, essentially. The blurring you seeing is caused by the way the rods and cones respond to light. It's a continuous image that you perceive not snapshots N times per second.", "1^st Question: > Eyes work like an analog way, instead of digital way. > Therefore no. 2^nd Question: > Your eyes cannot track the object because it is moving too fast. > Therefore, your brain adds motion blur to the object."], "text_urls": [[], []], "score": [8, 3]}}, {"q_id": "7nso9x", "category": "Repost", "title": "How do people become so addicted to alcohol they can\u2019t go a day without it?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ds488mb"], "text": ["Yarr! Yer not alone in askin', and kind strangers have explained: 1. [ELI5: Why can quitting drinking kill an alcoholic? ]( URL_0 ) ^(_54 comments_) 1. [ELI5: What is it exactly that alcoholics become addicted to? ]( URL_2 ) ^(_ > 100 comments_) 1. [ELI5: Why is alcohol supposedly very addictive, yet so few addicts are around (relatively)? Explain addiction to me. ]( URL_4 ) ^(_56 comments_) 1. [ELI5:Why is alcohol regarded differently from other addictive substances? ]( URL_1 ) ^(_80 comments_) 1. [ELI5: How do people get addicted to alcohol? ]( URL_3 ) ^(_6 comments_)"], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/1kgx4h/eli5_why_can_quitting_drinking_kill_an_alcoholic/", "https://www.reddit.com/r/explainlikeimfive/comments/3sni1z/eli5why_is_alcohol_regarded_differently_from/", "https://www.reddit.com/r/explainlikeimfive/comments/3toln8/eli5_what_is_it_exactly_that_alcoholics_become/", "https://www.reddit.com/r/explainlikeimfive/comments/1rt32a/eli5_how_do_people_get_addicted_to_alcohol/", "https://www.reddit.com/r/explainlikeimfive/comments/2yclea/eli5_why_is_alcohol_supposedly_very_addictive_yet/"]], "score": [3]}}, {"q_id": "7nsy1r", "category": "Repost", "title": "Wattage, voltage, amperage, and resistance", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ds4c06z", "ds4awfc", "ds4b13s"], "text": ["Think water in pipes: Voltage = water pressure Amperage (current) = volume of water that passes a single point in the pipe within a given time Resistance = inverse of pipe width voltage (water pressure) = Current x Resistance Power = water pressure x volume of water that passes a single point in the pipe over time more pressure through a given pipe diameter equals more flow, equals more power more voltage and less resistance equals more current", "Joule (J) is a measurement of energy. Coulomb (C) is charge, basically A * s Voltage (V) is J/C. Energy per charge. Ampere (I) is C/s. Charge per second. WATT is V * I; J/s. Energy per second. Resistance is V/I. If we think of electricity as packets. C is the package. V is the size of the package. I is the speed the package travels. Resistance is the speed limit/size restriction through a component. Be aware, this is a super simplistic view and does not accurately portray how electricity works. It's just a way to sort of understand the values.", "Compare it to a bus, with one elektron being a bus and the amount of people in the bus the energy that an elektron carries. Amperage would be the amount of busses that are driving. Voltage the amount of people per bus, wattage the total amount of people transported and resistance the amount of people a bus would lose going through an area. In more technical terms, Amperage is the amount of elektrons going through an area/point on a wire. Voltage the amount of energy that an elektron carries, Wattage the total amount of energy going through a point on a wire and resistance the amount of energy an elektron loses going through a part of a wire."], "text_urls": [[], [], []], "score": [3, 3, 3]}}, {"q_id": "7nt3fx", "category": "Repost", "title": "How was the speed of light determined to be 3*10^8 m/s?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ds4bk09"], "text": ["It was measured. This began with Galileo who attempted to measure the speed of light with lanterns on hills. He concluded that the speed of light was very fast. Measurements continued and continue to this day. You can research the Michelson Morley experiments which found that the speed of light is not changed by the speed of the Earth."], "text_urls": [[]], "score": [3]}}, {"q_id": "7ntvbo", "category": "Repost", "title": "How does laser eye surgery work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ds4g1y4", "ds4fvgm"], "text": ["Idk how the fuck it works but I'll tell you how it went for me. -tests done to see if I'm a candidate. -I wasn't a candidate for the \"best one\" so they opted me in for the \"2nd best\" -I said fuck it let's do this shit. -2 weeks with glasses because my eyes had scars (or some shit) due To contacts. -sign a bunch of shit so I won't sue em. -walk in (nervous as fuck) for the surgery. -they installed some metal eye opening stuff on my eyes so my eyes can't close. -they put numbing drops on my eyes. -some hydrating drops. -and more numbing drops. -Dr, optometrist, guy burning my eyes dude, touches my eyes. \"do you feel that?\". -\"hell the fuck no I don't! Let's get it on!\" -Green (not red laser like everybody expects) laser on my eyes for about 23.72 seconds each eye. -smell burning Fucking flesh!!! -close eyes, put on glasses, walk out with blurry vision and vicodin. -wake up (after sleeping Fucking 14 hours) with sensitivity to light for 48 hours, eyes crying for 48 hours... -i had to do steroid drops on my eyes (which taste like sour milk down my gullet) and hydration drops 3 to 17 times a day. -then after a week or so I got fucking 20/20 vision! -10/10 would do it again. Edited for drunken antincts.", "They remove a really small piece from top of your eyes which is a \"lens\" that focuses incoming light. This makes the light go correctly where it's supposed to go."], "text_urls": [[], []], "score": [18, 3]}}, {"q_id": "7ntzot", "category": "Repost", "title": "Guns and Sights", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ds4gls8", "ds4gnf5"], "text": ["It's called [sighting in or zeroing]( URL_0 ) The sights can be manually calibrated by moving knobs on the optics themselves, causing it to aim down slightly so the barrel of the gun is pointed ever-so-slightly up. So when aiming at a distant target, your sights are directly on the target, but the bullet flies slightly up and falls through the air in an arc, before landing where you were aiming.", "It's not just your barrel being lower. At extremely close ranges, this can pose a significant difference, but at longer ranges gravity also starts pulling your bullet down. The solution to this is that sights are ranged, and have built in or adjustable correction for these things - the technical term, I believe, being to 'zero' your shot. As you shoot further away, you need to aim the barrel further up to hit the same level above ground. So sights have settings for this - set to the range the target is approximately at - so that the point in the bullets parabolic trajectory intersects exactly with the point the sight is aimed. As visible on the top of this image - the striped line is the line that'd be looked along down the scope, the dotted line is the straight extension of the barrel, and the solid line is the path the bullet actually follows. URL_0"], "text_urls": [["https://en.wikipedia.org/wiki/Sighting_in"], ["https://defensivetraininggroup.files.wordpress.com/2015/03/battle-sight-zero.jpg"]], "score": [13, 5]}}, {"q_id": "7nu3yq", "category": "Repost", "title": "- How are fuel prices at the pump determined and why do they fluctuate every day?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ds4hmwq", "ds4hdoz"], "text": ["If they think oil prices are going up, they raise prices. If they think oil prices are going down, they leave prices up to make more profit. If they think people will be travelling, they raise prices because of more demand. If they think people won't be travelling, they raise prices because of too little demand. About the only time prices go down is when there's a national election.", "I am certainly no expert, but from what I understand it's the cost of crude oil, which is affected by various things, such as geopolitical issues. As far as I know most other costs are fairly fixed; taxes, marketing, transport, etc... So the fluctuations at the pump are due to fluctuations in the price of the raw product. But other things can come in to play as well. Here is a good [article]( URL_0 ) explaining the factors."], "text_urls": [[], ["https://www.google.com.au/amp/s/amp.businessinsider.com/factors-that-determine-gas-price-2012-5"]], "score": [4, 4]}}, {"q_id": "7nzl0w", "category": "Repost", "title": "Why does the earth being 1 degree warmer so significant?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ds5p5po"], "text": ["> If the weather was warmer by a degree on average every day there would be no difference. Well, that isn't what is being talked about. Instead think about how much energy is required to heat up the entire atmosphere and surface of Earth by one degree. A huge amount! That much energy being at work in the atmosphere can mean more powerful weather effects in the short term or in a specific area. Also think about how it gets colder as you move toward the poles. At some point water starts to freeze to ice. Now if you raise the overall temperature by one degree this would mean that point where water freezes consistently would move closer to the poles by some amount. As the change is very gradual this might mean like 100 miles, in a strip all the way around the planet for both poles. How much area is that?! And it isn't like that line is always in the same place throughout the year so ice melting at different times than normal can translate to unpredictable changes in the weather."], "text_urls": [[]], "score": [3]}}, {"q_id": "7o0h9a", "category": "Repost", "title": "What happens to dead birds? How come we don't see them dropping from the skies when they die and we don't see millions of dead birds all over the place? Where do they all go?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ds5w71g", "ds5wbbq"], "text": ["Other things eat them. Vultures, raccoons, foxes, rodents, insects, etc. Nature has a cleaning crew.", "Why would they be dropping from the sky in large enough amounts for you to notice? Those that are ill or otherwise dying are likely not able to fly. Why would we see millions of them all over the place? Corpses are scavenged and decompose, like all other dead animals."], "text_urls": [[], []], "score": [7, 3]}}, {"q_id": "7o1fdq", "category": "Repost", "title": "Why does food taste weird after brushing your teeth?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ds64ju6"], "text": ["My guess would be the minty aftertaste. Same reason it tastes funny after chewing gum. I\u2019m probably wrong but I figured I\u2019d throw in my 2 cents"], "text_urls": [[]], "score": [3]}}, {"q_id": "7o1glf", "category": "Repost", "title": "Why are people screaming Fake News when yellow journalism has been around as long as we can remember? Are they different?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ds63f7g"], "text": ["Yo ho ho! Yer not alone in askin', and kind strangers have explained: 1. [Why has the term \"fake news\" become so popular lately? Didn't we already have words for that - lies and/or propaganda? ]( URL_2 ) ^(_13 comments_) 1. [Why did it take until 2016 for fake news to enter common slang terms and become part of popular culture? ]( URL_0 ) ^(_._) 1. [ELI5: Why was \"Fake News\" added to the dictionary this year when its just made of two standard words being used appropriately? ]( URL_1 ) ^(_6 comments_)"], "text_urls": [["https://www.reddit.com/r/NoStupidQuestions/comments/7fxkvb/why_did_it_take_until_2016_for_fake_news_to_enter/", "https://www.reddit.com/r/explainlikeimfive/comments/7cvoy2/eli5_why_was_fake_news_added_to_the_dictionary/", "https://www.reddit.com/r/NoStupidQuestions/comments/7jt3pn/why_has_the_term_fake_news_become_so_popular/"]], "score": [3]}}, {"q_id": "7o2nkk", "category": "Repost", "title": "why were dinosaurs much larger than most animals we see today?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ds6clvr", "ds6avj8"], "text": ["the oxygen theories posted as other comments applies to insects, not dinosaurs. URL_1 the following theories are not mutually exclusive (meaning it's not #1 or #2, it could be #1 *and* #2 etc.). and tl;dr **we don't know for sure**, all the theories are controversial. theory #1 for dinosaurs: the mesozoic era (~250 million years ago - 65 million years ago, the time period all dinosaurs lived in) had much higher levels of carbon dioxide (co2) in the atmosphere. more co2 = higher temperatures. plants feed (via photosynthesis) off of co2, and higher temperatures promote more vegetative growth. the theory is that some dinosaurs were so big simply because there was so much for them to eat, which would explain why some herbivores were much larger than carnivores. note that the only dinosaurs that were small were carnivores, almost all herbivores were taller than 1 meter. this theory is also being challenged though ( URL_2 ) theory #2: hugeness was simply an evolutionary defense mechanism theory #3: if dinosaurs were cold blooded, as many paleontologists believe, their size could be a way to maintain their internal temperatures despite environmental circumstances. \"a house-sized, homeothermic Argentinosaurus could warm up slowly (in the sun, during the day) and cool down equally slowly (at night), giving it a fairly constant average body temperature--whereas a smaller reptile would be at the mercy of ambient temperatures on an hour-by-hour basis.\" ( URL_0 ) see also URL_3 theory #4: larger size = lower metabolism, longer digestion = bigger dinosaurs need less food. there's probably more out there, but these were the main ones that i found on google.", "Higher oxygen content in the air allowed animals to grow to a much larger size. Their hearts didn't have to work as hard to pump oxygen through their body because there was more of it."], "text_urls": [["https://www.thoughtco.com/why-were-dinosaurs-so-big-1092128", "https://news.nationalgeographic.com/news/2011/08/110808-ancient-insects-bugs-giants-oxygen-animals-science/", "http://www.pnas.org/content/109/26/10403", "https://www.livescience.com/5527-dinosaurs-big.html"], []], "score": [7, 3]}}, {"q_id": "7o3sqq", "category": "Repost", "title": "How do snails make their shells?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ds6k4at"], "text": ["Shells of things like snails and clams have shells made (primarily) of calcium carbonate. There's some protein in there too, but it's just a chemical that their bodies produce in a structured way over time. I guess it's analogous to how you grow hair or fingernails, but instead of growing the protein keratin they're putting down layers of calcium ions in a crystal lattice."], "text_urls": [[]], "score": [3]}}, {"q_id": "7o3tmq", "category": "Repost", "title": "Game engines: what are they and why are new ones always needed?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ds6l2l2"], "text": ["So let's say you run a game studio that is making two very different games. One is a cute adventure game for kids where a princess has to rescue her animal friends from an evil witch. Another is a bloody shooter where a battle hardened soldier has to save the world from vicious aliens. Now, these games are wildly different thematically, but beneath the surface they both have a lot in common. They both need a way to render 3D graphics, as well as a 2D user interface. They both need to play music and sound effects. They both need to save and load the player's progress. They both need to detect collisions between the player character and the world around them. You don't want to do all that work twice, so you do it once and build it in a way that it can be used by both games, and possibly reused by others. This library of underlying tools and functionality is what you would call the game engine. New ones are needed for the same reason we need new anything. Sometimes the old ones just don't offer the power and flexibility that people want. A company may decide to make their own proprietary engine either because they aren't satisfied with what's available, or because they just don't want to pay to license what someone else made."], "text_urls": [[]], "score": [4]}}, {"q_id": "7o9sjv", "category": "Repost", "title": "How pyramid schemes work", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ds7vh73"], "text": ["OP, I can sell you 100 plumbuses at 10 dollars a pop. If youre wondering what you would ever do with so many plumbuses, well you could sell 20 of them to 5 at other people at 15 dollars each, making you a hefty profit. Why would anyone buy 20 plumbuses from you? Well just tell them that they can sell 4 of them to to 5 other people at 20 dollars each, making them a nice profit for themselves too. Everyone wins."], "text_urls": [[]], "score": [6]}}, {"q_id": "7oe4kn", "category": "Repost", "title": "Why do amplifiers read volume in negative decibels?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ds8sl14"], "text": ["Decibels are used to measure sound volume, that's the usage of them that you are likely most familiar with. However, they are also a way of expressing a ratio. If you have a given signal strength, you can then express the strength of another signal in terms of decibels as related to that original signal. (Negative decibels would be weaker, positive decibels stronger) Most amp manufacturers aim to have a 0dB volume ratio mean \"as loud as we can get without distortion\", that is, super, super loud. You can therefore understand why most of the time we listen to the stereo, it is at negative decibels, i.e., weaker than \"as loud as we can get without distortion\"."], "text_urls": [[]], "score": [4]}}, {"q_id": "7oerlt", "category": "Repost", "title": "Why is ice slippery?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ds8z5v3", "ds8z3fo", "ds8z8qc", "ds90fay"], "text": ["I was once told it\u2019s due to the pressure from an object (a shoe, a tire, etc). The pressure creates a thin water barrier between the object and the ice surface and reduces friction significantly.", "Typical ambient air temperatures will cause a thin layer of the water molecules on the surface of the solid ice to melt into liquid form. The layer of liquid water will cause things to be a little more mobile when they touch.", "When you step on it, the pressure of your weight liquefies the top of the ice slightly, so you slide around on a thin layer of water. Notice that there has to be enough pressure or heat to melt it for it to be slippery.", "These answers about pressure melting ice are a common misconception. If you look at the phase diagram of water you will see that it takes an absurd amount of pressure to do that. Ice is a lattice structure, and the top layer of molecules can\u2019t fully participate in the lattice, so they can be thought of as liquid"], "text_urls": [[], [], [], []], "score": [7, 3, 3, 3]}}, {"q_id": "7offqe", "category": "Repost", "title": "How does the tab under a rearview mirror dim lights when hitting it?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ds94dhu", "ds96h6b"], "text": ["It does indeed change the angle. The Mirror looks something like this: |\\ The left line being the mirror, reflecting all things behind you. The right line is the glass in front of the mirror, angled differently. When you press the button, the angle changes, to look like this: /| The mirror is now pointing downward and reflecting the headlights down, where they do not disturb your vision. Since it is probably dark/night you can now still see the much dimmer reflection of the glass instead.", "I've searched tha seven seas fer an answer. Yer not alone in askin', and kind strangers have explained: 1. [ELI5: How \"flipping\" my car's rear view mirror makes it more dim (instead of just showing me my back seat). ]( URL_5 ) ^(_3 comments_) 1. [ELI5: How does the tab on my car mirror dim the reflection? ]( URL_3 ) ^(_1 comment_) 1. [How the fuck does my rear view mirror show the same exact image but dimmer when I pull the tab down? ]( URL_1 ) ^(_6 comments_) 1. [ELI5: How does the rear view mirror work after flipping it up at night? ]( URL_0 ) ^(_37 comments_) 1. [ELI5: Why tilting your rear-view mirror makes headlights dim. ]( URL_6 ) ^(_3 comments_) 1. [ELI5: The tab under my rearview mirror, when flicked, removes glare from headlights. How? ]( URL_4 ) ^(_8 comments_) 1. [ELI5: How does my rear view mirror get dim when I push the little tab on the bottom? ]( URL_2 ) ^(_2 comments_)"], "text_urls": [[], ["https://www.reddit.com/r/explainlikeimfive/comments/3ji34o/eli5_how_does_the_rear_view_mirror_work_after/", "https://www.reddit.com/r/NoStupidQuestions/comments/526z7n/how_the_fuck_does_my_rear_view_mirror_show_the/", "https://www.reddit.com/r/explainlikeimfive/comments/18xnzx/eli5_how_does_my_rear_view_mirror_get_dim_when_i/", "https://www.reddit.com/r/explainlikeimfive/comments/15m9m2/eli5_how_does_the_tab_on_my_car_mirror_dim_the/", "https://www.reddit.com/r/explainlikeimfive/comments/3s2gfe/eli5_the_tab_under_my_rearview_mirror_when/", "https://www.reddit.com/r/explainlikeimfive/comments/1q32u9/eli5_how_flipping_my_cars_rear_view_mirror_makes/", "https://www.reddit.com/r/explainlikeimfive/comments/ks4ez/eli5_why_tilting_your_rearview_mirror_makes/"]], "score": [12, 4]}}, {"q_id": "7ofshh", "category": "Repost", "title": "Can someone explain the year 2038 problem and what the consequences are exactly?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ds96fst", "ds963ji"], "text": ["Yo ho ho! Yer not alone in askin', and kind strangers have explained: 1. [ELI5: The year 2038 problem. ]( URL_0 ) ^(_74 comments_) 1. [ELI5:Year 2038 Problem ]( URL_1 ) ^(_ > 100 comments_) 1. [ELI5: The year 2038 problem for computing systems? ]( URL_2 ) ^(_22 comments_) 1. [ELI5: The Year 2038 Problem ]( URL_5 ) ^(_20 comments_) 1. [ELI5: The Year 2038 problem ]( URL_4 ) ^(_6 comments_) 1. [ELI5:The 2038 problem. ]( URL_3 ) ^(_ > 100 comments_)", "Computers run out of numbers for counting time. Basically current systems use 32-bit intergers to measure seconds then these seconds are added to 1/1/70 0001:01 and give the current time. Well in 2038 current systems won't be able to count any higher so it'll revert back 1. It's similar to the Y2K issue in which systems couldn't account for 2000. It's not really an issue. Every information system should be updated before then. Most are already compatible with 64bit intergers. The worst thing is that old Commodore 64 collecting dust will have the wrong time."], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/1wb3c2/eli5_the_year_2038_problem/", "https://www.reddit.com/r/explainlikeimfive/comments/3yws9v/eli5year_2038_problem/", "https://www.reddit.com/r/explainlikeimfive/comments/61ys7s/eli5_the_year_2038_problem_for_computing_systems/", "https://www.reddit.com/r/explainlikeimfive/comments/3npc2l/eli5the_2038_problem/", "https://www.reddit.com/r/explainlikeimfive/comments/ypfg1/eli5_the_year_2038_problem/", "https://www.reddit.com/r/explainlikeimfive/comments/2euj2o/eli5_the_year_2038_problem/"], []], "score": [8, 8]}}, {"q_id": "7ok9xw", "category": "Repost", "title": "Now that we've found the Higgs Boson, what has it taught us about mass, or why objects have mass?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dsa90hl", "dsa5tte", "dsarqzx", "dsa8syh"], "text": ["Mass is a term claimed for how much an object interacts with the Higgs field. Think of water in a bucket. Each of the water molecules are interacting with eachother with hydrogen bonds. You stick your hand in the bucket, displacing water molecules around your hand. The Higgs field is exactly like water. But instead of water molecules there are little Higgs bosons. Thus if you have an object that interacts more with the Higgs field, then more Higgs bosons are displaced creating more mass.", "It hasn't really taught us anything knew, it's confirmed some theories. The properties and impact were predicted by Dr. Higgs and his successors from the 1960s forward, the problem was just seeing if the thing actually existed.", "As a preface, note that any layman-friendly explanation you will encounter here is going to be a gross oversimplification of the Higgs-mechanism, so take everything with a grain of salt (including this comment). To clear up some confusion that I've seen in this thread, first lets talk about something a little more fundamental, the Pauli-exclusion principle (PEP). It says that no two Fermions (particles that ordinary matter is made up of) can occupy the same quantum state (i.e position, angular momentum, energy etc). This is why we expect some resistance if we're trying to squish something together, for example. Now, Bosons are different from Fermions. They don't obey the PEP and as a consequence can be packed arbitrarily close together. This is for example why stating that particles gain mass by \"displacing\" Higgs-Bosons is not true, Bosons cannot be displaced. Anyways, back to your question. Particles gain mass by _interacting_ with an omnipresent Higgs _field_ that permeates all of space. The best way to think of this field is a room full of your friends (bear with me, this will all make sense in a moment). The people inside are _excitations_ of this room, much like the Higgs-Boson is an excitation of the above discussed Higgs field. Suppose now you want to go trough the room. Of course every single one of your friends will want to talk with you, slowing you down along the way. Meanwhile a complete stranger with the same path would get to their destination much faster, as only few people would slow them down with a conversation. A similar thing happens with particles. Their coupling strength (or popularity, in our analogy) determines how drastically they're \"slowed down\". the more they interact with the Higgs field, the more mass they get and vice versa. As I mentioned above, this is not a complete rundown on the mechanism, but seeing as it nevertheless is a pretty lengthy wall of text already I will stop here. If you have any follow up questions, feel free to ask.", "I am curious to see if we can manipulate the Higgs and make matter have more or less mass than normal. Imagine high tensile strength steel wires that are a couple inches thick and yet per foot of length weighs the same as spider silk. More a what if than a reality"], "text_urls": [[], [], [], []], "score": [479, 34, 29, 5]}}, {"q_id": "7omwsl", "category": "Repost", "title": "Why can we make bluray versions of old movies that look better but cant make better quality versions of old songs?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dsanxmj", "dsaobyd"], "text": ["We can and they do. And they do it in pretty much the exact way that they restore films. They go back to the original recordings, clean them up, and remaster them.", "The general principles behind releasing anything of higher quality is that you can't improve what you don't have. With movies, they were shot on film which is way higher quality than you might think. They simply have the information to work with and their only limiting factor is the medium that you are producing for. Note for things shot on videotape, you don't get better quality, often times you get worse Older songs though have different issues given the medium that they were recorded to with mediums that weren't as high quality as you think. But there is a wide variety of mediums and techniques used in recording and that limits you since your master can vary so much. SO if your source was good enough for the medium of the era, you are going to have to go through a lot of work to clean it out and if your source is crap, you can only do so much. TLDR - different mediums over time with different levels of quality."], "text_urls": [[], []], "score": [10, 4]}}, {"q_id": "7ou27k", "category": "Repost", "title": "If your skin is constantly growing and shedding off of your body, then how are tattoos permanent?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dsc98r0"], "text": ["The outer layer of your skin is sloughed off constantly, yes. But tattoos deposit ink deeper than this, where it's not shedding off."], "text_urls": [[]], "score": [3]}}, {"q_id": "7oydhz", "category": "Repost", "title": "When you have an internal organ removed, what does your body do with all of the new space in your chest\\abdomen?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dsd4rm9"], "text": ["Generally it closes the hole back up with fluids or meatstuff. In the event of a kidney removal, for example, the hole just closes up over the course of a few months. In the event of a partial brain removal, cerebrospinal fluid fills in the hole. Our bodies don't enjoy having holes in them, so they do a pretty good job of tidying it up."], "text_urls": [[]], "score": [4]}}, {"q_id": "7p1fw1", "category": "Repost", "title": "Why do certain smells get stuck on clothes?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dsdrqq5", "dsdrum8"], "text": ["Yo ho ho! Yer not alone in askin', and kind strangers have explained: 1. [ELI5: Why do smells \"cling\" to you? ]( URL_8 ) ^(_2 comments_) 1. [ELI5: What makes clothing hold onto certain odors? ]( URL_5 ) ^(_1 comment_) 1. [ELI5:Why do some smells stay on clothes? ]( URL_6 ) ^(_1 comment_) 1. [ELI5: Why does the smell of Indian food stick to me so greatly? ]( URL_0 ) ^(_1 comment_) 1. [ELI5: How can the smell of cigarette smoke stay in walls, curtains, clothes, etc. for long periods of time, but smells like perfumes, casseroles, other foods, etc. do not linger for more than a couple of days usually? ]( URL_7 ) ^(_ > 100 comments_) 1. [ELI5: Why does the smell of smoke \"stick\" to you? ]( URL_1 ) ^(_2 comments_) 1. [ELI5:Why do clothes put away in storage come out with a smell? ]( URL_4 ) ^(_ > 100 comments_) 1. [ELI5: Why do some odors attach to clothing and some don't? ]( URL_3 ) ^(_3 comments_) 1. [ELI5: How do things (like your body or clothes) absorb odors and smells? ]( URL_2 ) ^(_1 comment_)", "When you smell something, what you're actually smelling are gasses and particles given off by the thing you're smelling. With some smells, like smoke, the gasses are accompanied by particles that get ingrained in fabric. Those particles continue to break down and become airborne, allowing the smell to linger far longer than anyone wants it to."], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/3g89ib/eli5_why_does_the_smell_of_indian_food_stick_to/", "https://www.reddit.com/r/explainlikeimfive/comments/54erpl/eli5_why_does_the_smell_of_smoke_stick_to_you/", "https://www.reddit.com/r/explainlikeimfive/comments/6kpsyh/eli5_how_do_things_like_your_body_or_clothes/", "https://www.reddit.com/r/explainlikeimfive/comments/4vjl6j/eli5_why_do_some_odors_attach_to_clothing_and/", "https://www.reddit.com/r/explainlikeimfive/comments/2mk7yd/eli5why_do_clothes_put_away_in_storage_come_out/", "https://www.reddit.com/r/explainlikeimfive/comments/49ai56/eli5_what_makes_clothing_hold_onto_certain_odors/", "https://www.reddit.com/r/explainlikeimfive/comments/2z4ea4/eli5why_do_some_smells_stay_on_clothes/", "https://www.reddit.com/r/explainlikeimfive/comments/3mfisk/eli5_how_can_the_smell_of_cigarette_smoke_stay_in/", "https://www.reddit.com/r/explainlikeimfive/comments/uy9nm/eli5_why_do_smells_cling_to_you/"], []], "score": [5, 3]}}, {"q_id": "7p2g2j", "category": "Repost", "title": "How is windchill measured?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dsdzj4s", "dse42xt"], "text": ["It isn't measured. It's calculated. WC = 35.74 + 0.6215T \u2013 35.75(V^0.16) + 0.4275T(V^0.16) Where T is temperature and V is wind speed.", "Yer not alone in askin', and kind strangers have explained: 1. [ELI5: How is wind chill measured? ]( URL_1 ) ^(_1 comment_) 1. [ELI5:This is a little late, but explain how wind chill works. ]( URL_0 ) ^(_2 comments_) 1. [ELI5: How does wind chill work? ]( URL_4 ) ^(_10 comments_) 1. [ELI5: How do we know how much colder the windchill feels? ]( URL_3 ) ^(_2 comments_) 1. [ELI5: Wind chill ]( URL_5 ) ^(_12 comments_) 1. [ELI5: What exactly are the heat index and wind chill, and how wre they measured? ]( URL_2 ) ^(_1 comment_)"], "text_urls": [[], ["https://www.reddit.com/r/explainlikeimfive/comments/217o63/eli5this_is_a_little_late_but_explain_how_wind/", "https://www.reddit.com/r/explainlikeimfive/comments/1pjvwq/eli5_how_is_wind_chill_measured/", "https://www.reddit.com/r/explainlikeimfive/comments/2ee50i/eli5_what_exactly_are_the_heat_index_and_wind/", "https://www.reddit.com/r/explainlikeimfive/comments/3tguxl/eli5_how_do_we_know_how_much_colder_the_windchill/", "https://www.reddit.com/r/explainlikeimfive/comments/1ujq5p/eli5_how_does_wind_chill_work/", "https://www.reddit.com/r/explainlikeimfive/comments/2lgxyq/eli5_wind_chill/"]], "score": [5, 3]}}, {"q_id": "7p670m", "category": "Repost", "title": "why does detecting road signs prove I am human on the internet?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dsetab2", "dsetair", "dsetn1h", "dseugap"], "text": ["Most bots that try to steal accounts probably aren't set up to recognize road signs. Meanwhile, the captcha doubles as you helping train image recognition bots for self driving cars.", "As with all \"captchas\", it's about making it more expensive for artificial intelligence to solve it. The goal is that it would cost more to have it solved than an unwanted access would yield in returns. Analyzing the pictures for road-signs is possible but currently (still) too complicated to be implemented in AI cheaply enough for it to pay off.", "You feed an AI a few million pictures and tell it thats signs. And a few million other pictures and tell it thoes are not signs. But you want to be able to use the same AI for other stuff than just signs. As an example, telling dogs from bees. AIs have great dificulty telling things apart that are edge cases. A [dog in a bee suit]( URL_1 ) a human would be no problem for a human. Or what if you looked at a blury image? Or a drawing perfaps? That said CGP Greys video [How Machines Learn]( URL_2 ) (and the [follow up video]( URL_0 )) explains it better than I ever could if you have 10mins to spend < 3", "There is a little more to it that other comments haven\u2019t addressed. The software you are talking about is called [reCAPTCHA]( URL_0 ) If you look at the images there you will recognise the older version with suspicious looking book text. The system works on guessing and learning. reCAPTCHA doesn\u2019t know the 100% correct answer - but it can guess close enough. If your answer matches its guess close enough, then you pass. It then looks at all the data it has collected from everyone answering the same specific questions with the same specific images, and the software looks at trends of the most common answers. It accepts that as correct, and updates its algorithms to be more correct in future. When you use it, you are teaching Google\u2019s computers how to identify road signs better in future. The older style one with text was really cool, Google wants to have every book ever stored on its computers, and stored as text, not just scans of books. Whenever the algorithm came across a word it didn\u2019t know - usually due to either poor quality scans, or print errors or wear and tear on books, it would include it in a reCAPTCHA, along with a word it was sure about. Eventually by collecting everyone\u2019s answers, it was able to learn how to read that word. This is called Machine Learning. No person anywhere can write a computer program to correctly identify road signs, but a computer can be given an insanely large amount of data (the squares you do and don\u2019t click on) and be told to use that data to come up with its own algorithm for identifying road signs. Every time you do and don\u2019t click a road sign, it compares it to its algorithm, and it then either decides you are wrong, and therefore you fail, or it\u2019s algorithm is wrong, and it makes a minor change and it won\u2019t make the same mistake next time. I think eventually we will see this implemented in to Google Maps were Google can read every road sign."], "text_urls": [[], [], ["https://www.youtube.com/watch?v=wvWpdrfoEv0", "https://cdn.shopify.com/s/files/1/0766/5767/products/Bumble-Bee-Costume-for-dogs_large.jpg?v=1441092354", "https://www.youtube.com/watch?v=R9OHn5ZF4Uo"], ["https://en.wikipedia.org/wiki/ReCAPTCHA"]], "score": [11, 3, 3, 3]}}, {"q_id": "7p6lpt", "category": "Repost", "title": "Why are upload speeds significantly lower than download speeds?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dsevsuj"], "text": ["In short, because ISPs (Internet Service Providers) prioritize download speeds rather than upload speeds. This is because they assume most people are downloading than uploading."], "text_urls": [[]], "score": [5]}}, {"q_id": "7pcc9y", "category": "Repost", "title": "I have a question on Ohms and Speaker impedance.", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dsgrc7f"], "text": ["Speaker impedance is ohms, they're the same. They represent the resistance in the coil of the speaker. If its too low it'll try to pull more current than the amp can handle, too high and the amp won't be able to deliver enough power to it. You want the Ohms/Impedance of your speakers to be within the range that the amplifier supports, and you want their power rating to be greater than or equal to the amp. An amp that can provide more power than the speakers can handle can burn them out."], "text_urls": [[]], "score": [3]}}, {"q_id": "7pegqv", "category": "Repost", "title": "Why earth maps have always been drawn with the \"North up / South down\" orientation?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dsglzom", "dsglyvv", "dsgm1z7", "dsgrdf6"], "text": ["They haven't been, the key was the word orientation. There was a time they were organised facing the orient, or east.", "Because it was more convenient for the people who drew them: 1. Most of Earth's landmass and population is in the Northern hemisphere. 2. The people who drew these maps are mostly Europeans, which is also why Europe is in the middle.", "I feel like we used the stars to navigate at one point, using the north star as a reference of true north. Plotting a course relative to something that's always north probably reduced the amount of lost or missing verses at one point", "Until the sixteenth century most maps had east on top. When compasses began being widely used, it made sense to align the map to the compass. When you're you're looking down at your compass pointing straight in front of you, you are facing north. So the map is drawn to align to a north facing person."], "text_urls": [[], [], [], []], "score": [18, 11, 6, 4]}}, {"q_id": "7pepag", "category": "Repost", "title": "How film editors used to edit movie in older times without computers?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dsgnbtc", "dsgnh7a"], "text": ["By literally cutting and taping together pieces of the film. At first they would do this completely by hand, later on [machines that helped with editing]( URL_0 ) were created.", "Old movies were filmed on celluloid film reels, in the editing room directors would cut scenes... merge footage and change colours literally on the reel rather than through digital processing. A good movie that proves a quick demonstration of how it used to work is Fight Club, when Tyler Durden does some film editing at a cinema. Some directors still use this approach, Christopher Nolan, Quentin Tarantino"], "text_urls": [["https://en.wikipedia.org/wiki/Moviola"], []], "score": [10, 3]}}, {"q_id": "7pjdfm", "category": "Repost", "title": "Why have Jewish people been persecuted so much historically?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dshq0x1", "dshpurr"], "text": ["Early Christian edicts stated that Christians were not allowed to collect interest on loans. Because of that, there was no incentive for any Christian to make any loans--since they will risk not getting the money back for no potential gain. Jews did not have this restriction, therefore they became the bankers. If a King or Duke needed extra funds for something immediate, they had to go to a Jew. This made many of them rich (since interest is a good way to make money) and unpopular (since nobody likes paying interest). This then makes them a target--if your debt gets too high or if you think confiscating money is the best way to get quick cash, use them as a scapegoat for whatever dastardly rumor you want.", "For a lot of European history the Jews were an insular but also obvious minority. They spoke a different language, lived in separate communities, practiced a foreign religion, and dressed and acted in strange (to European Christians) ways. Jews were also often relegated to undesirable professions (itinerant trading, money lending, etc) due to prohibitions on them owning land or settling in certain areas. All of this made them easy targets for scapegoating, especially in a time when for the vast majority of people their only real interaction with the world outside their village was through the Catholic Church."], "text_urls": [[], []], "score": [7, 3]}}, {"q_id": "7pky8j", "category": "Repost", "title": "why do cold symptoms seem stronger/worse later in the day or before sleep as compared to during the day when you\u2019re active?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dsi2vqn"], "text": ["Your immune system has a circadian rhythm much like your sleep cycle. During midday, functions related to cell immunity\u2014antibody production and macrophage activity\u2014dominate. During the night, these ramp down in favor of discomforting\u2014but healing\u2014inflammation functions. [Source (just googled)]( URL_0 )"], "text_urls": [["http://m.huffingtonpost.ca/jason-tetro/colds-flu-worse-at-night_b_14303482.html"]], "score": [6]}}, {"q_id": "7pmyqg", "category": "Repost", "title": "How do record players turn physical rivets into any possible sound from any instrument?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dsigvr4", "dsihfk5"], "text": ["Every sound from every instrument is, at its simplest level, air vibrating at a specific frequency. If you can reproduce that exact frequency, you can produce the sound of anything you want: instruments, animals, speech, whatever. As a record needle bounces within the grooves of a record, it's picking up those vibrations and sending the signal to the speaker, which pumps out the frequency of the sound.", "all sounds are just little vibrations in the air, and all those vibrations add up to make a single wave at any given moment. the microphone is hit by the wave and converts it into electrical pulses. those electrical signals are then converted into mechanical power, which cut the master disc in a pattern. through some manufacturing wizardry, the master is used to create the vinyl record. when set to play, the grooves in the vinyl push the needle around, causing it to close an electrical circuit, reproducing the same electrical pulses the microphone created when it was recording. those signals are amplified and sent to the speaker, which then pushes air."], "text_urls": [[], []], "score": [5, 3]}}, {"q_id": "7po4ff", "category": "Repost", "title": "What is that ear hurting noise that happens when you have one window of the car open while driving fast?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dsioevp", "dsio2id"], "text": ["If you have a large volume of air with a small hole to the outside, the air can start to resonate. That means that air is pushed inside by the motion of the car, increasing pressure inside your car. The rising pressure will stop more air from rushing in, and then push it back back outside. This process repeats over and over again at a very rapid pace, creating a loud noise. It's the same effect that makes a sound when you blow over an open bottle, or helps increase the volume of subwoofers through bass reflex holes. The technical term for this is [helmholtz resonance]( URL_0 ).", "It\u2019s called wind buffeting, and happens when your open window interrupts the aerodynamics of the wind tornados passing over the sides of your car as you move."], "text_urls": [["https://en.wikipedia.org/wiki/Helmholtz_resonance"], []], "score": [38, 6]}}, {"q_id": "7pq2um", "category": "Repost", "title": "How come you can hold your bladder for hours, but as soon as a toilet enters your vision it feels as though you\u2019re going to explode?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dsj44i9"], "text": ["Your brain is what's suppressing the urge to urinate when it knows that there's no chance of urinating at the time. Once you're near a toilet, the suppressing wears off, and you feel the full urge to urinate. You can think of it as a measure to ensure that you take the opportunity to urinate when you can."], "text_urls": [[]], "score": [3]}}, {"q_id": "7ps7tb", "category": "Repost", "title": "why can we often \u201cfeel people staring at us\u201d? I have woken up at times because I could feel someone staring at me. Is there any science behind this?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dsjmef9"], "text": ["There is *psychology* behind it. Often you notice someone is around you because of faint noise, change in air currents, lighting, or temperature. The brief alarm over discovering someone often overwhelms the sensation that caused you to notice them in the first place. Also, there is a lot of confirmation bias here. If you wake up and someone *isn't* staring at you, it won't make much of an impression and you likely won't remember. In fact, it isn't unusual to wake up at nice and go back to sleep with no long-term memory of it. You only take note of those rare times someone was actually there."], "text_urls": [[]], "score": [5]}}, {"q_id": "7pt20u", "category": "Repost", "title": "Why is a small amount of inflation considered good for the economy?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dsjtqeg", "dsjtf88", "dsjtxab"], "text": ["You want some inflation to discourage currency hoarding and lower the effective cost of borrowing. If your money is never losing value, why risk investing it? Put in in your Scrooge McDuck vault. But if it's losing 2% a year, now you better get moving. For your average person 2% a year isn't a big deal, but for institutions that deal in billions that equates to a vast sum down the toilet if they don't keep their money pile moving. Inflation helps keep the cash flow going in a modern economy. Now for your average person, you don't have much in savings but you probably do have a mortgage. A thirty year mortgage. Over thirty years, inflation puts a real dent in the effective cost of the mortgage, and makes it cheaper for you to borrow money long term. Your payments don't change, but they're worth less every year.", "Ahoy, matey! Yer not alone in askin', and kind strangers have explained: 1. [ELI5: Why is a small inflation rate considered good but not, say, a small deflation rate? ]( URL_0 ) ^(_34 comments_) 1. [ELI5: Why is inflation good for an economy? ]( URL_4 ) ^(_6 comments_) 1. [ELI5: How is slow but basically unlimited inflation sustainable or even good for the economy? ]( URL_8 ) ^(_4 comments_) 1. [ELI5: Why is inflation considered good thing? ]( URL_3 ) ^(_22 comments_) 1. [ELI5: In a healthy or growing economy, is inflation inevitable? Is inflation necessarily a bad thing? ]( URL_7 ) ^(_2 comments_) 1. [ELI5: Why is there constant inflation of currency? ]( URL_2 ) ^(_15 comments_) 1. [Why is inflation considered a good thing? ]( URL_5 ) ^(_30 comments_) 1. [ELI5: Why is moderate inflation considered a good thing ]( URL_6 ) ^(_9 comments_) 1. [ELI5: Economic inflation. Why does money consistently decrease in value? ]( URL_1 ) ^(_15 comments_)", "Small amounts of inflation encourage spending and investment. If you're money becomes more valuable over time (as it would under a deflation), then why buy a house/TV/Car now, when you're dollar will be worth more next year? Or why take your money out of the bank and invest it? You're basically able to make money by just burying cash in your backyard. So why risk the market goes down? Why would a bank lend out money? Who needs to take a risk that lendee won't be able to pay it off? You're gaining value by letting it sit in your vault. All of these things lead to shitty economy, less spending, less movement of money, less jobs, and overall a worse standard of living. A small, controlled amount of inflation helps stimulate the economy."], "text_urls": [[], ["https://www.reddit.com/r/explainlikeimfive/comments/6gsoox/eli5_why_is_a_small_inflation_rate_considered/", "https://www.reddit.com/r/explainlikeimfive/comments/6t1p0i/eli5_economic_inflation_why_does_money/", "https://www.reddit.com/r/explainlikeimfive/comments/1qemc1/eli5_why_is_there_constant_inflation_of_currency/", "https://www.reddit.com/r/explainlikeimfive/comments/5l9yzq/eli5_why_is_inflation_considered_good_thing/", "https://www.reddit.com/r/explainlikeimfive/comments/3o36ei/eli5_why_is_inflation_good_for_an_economy/", "https://www.reddit.com/r/explainlikeimfive/comments/1tzybb/why_is_inflation_considered_a_good_thing/", "https://www.reddit.com/r/explainlikeimfive/comments/5ns0qz/eli5_why_is_moderate_inflation_considered_a_good/", "https://www.reddit.com/r/explainlikeimfive/comments/43b7cy/eli5_in_a_healthy_or_growing_economy_is_inflation/", "https://www.reddit.com/r/explainlikeimfive/comments/2h4j48/eli5_how_is_slow_but_basically_unlimited/"], []], "score": [16, 7, 3]}}, {"q_id": "7pvk05", "category": "Repost", "title": "Why is it that you when plug in a MacBook with a dead battery it instantly turns on but with an iPhone it takes time?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dskcaa8"], "text": ["Laptops are designed to run directly on mains electricity, so the electricity goes to the laptop and the battery is charged in the process. So even if you remove the battery the laptop will still turn on. But phones are designed to be only portable so all power goes to the battery and then to the phone."], "text_urls": [[]], "score": [8]}}, {"q_id": "7q01cg", "category": "Repost", "title": "How do electronics lose charge while not being used?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dslbrqw", "dslde72"], "text": ["The chemical reactions in batteries don't stop, even when not in use. As time goes on, this reduces the free charge and capacity of the battery. Most batteries nowadays are relatively efficient when not in use, but there will always be a small drainage of energy over time.", "Some electronics never fully turn off, they're in low-power mode to keep internal clocks, infrared detector, etc. active."], "text_urls": [[], []], "score": [8, 4]}}, {"q_id": "7q1sym", "category": "Repost", "title": "What really determines stock prices?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dslsgim", "dslqyfp"], "text": ["**In theory:** The price of a stock is the net present value of all future dividends to be paid on that stock. Since this is ELI5, I can break that down a bit more. A \"dividend\" is a portion of a company's profits that is paid to shareholders. Some companies pay dividends every year, others (often tech startups) will go decades without paying a single dividend. No successful company can go its entire existence without ever paying dividends. Microsoft was founded in [1975]( URL_3 ) and paid its first dividend in [2003]( URL_2 ). Amazon was founded in [1994]( URL_1 ) and still [hasn't paid]( URL_0 ) a dividend. Stocks can have high prices even when they don't pay dividends because it isn't the current dividend that matters, it's the value of all dividends in the future. So, Amazon's stock price is currently $1300 because people expect that all future dividends to be paid on each share of stock will total $1300. We say \"net present value\" because money today is worth more than money tomorrow, so we consider that as part of the calculation; e.g. a $50 dividend paid out a decade from now is only worth $41.01 today, assuming 2% inflation, therefore that $50 has a \"net present value\" of $41.01. **In practice:** Occasionally, short term fluctuations have easy explanations. Did Apple report lower earnings than expected in the second quarter? Their stock price will go down, because lower earnings mean lower dividends. Note that what matters isn't their actual earnings, but the difference between their expected earnings and their actual earnings. This is because, before the earnings report, knowledge of the expected earnings is already included in the stock price. Similarly, a company issuing a recall or announcing that a new product will go to market sooner than expected will expect a quick change in stock price. The stock market is a market. The price is where the supply and demand curves meet. Short term changes in that price are almost completely random (with notable exceptions, listed above). Medium term changes in that price are highly correlated with (people's confidence in) the overall health of the economy or the specific industry of which the company is a part. It is only in the long term that the theoretical relationship between dividends and price holds. And, in the long term, we're all dead. EDIT: u/Phage0070 has helpfully pointed out that I forgot to mention that the assets of a company (and its expected future assets), such as the computers and manufacturing equipment it owns, are also included in the theoretical value of the stock price. This is because if the company were to suddenly stop existing the shareholder could still recoup value by selling off those assets.", "supply and demand. there's millions of potential buyers with varying levels of demand. there's millions of potential sellers with varying levels of supply. each buyer and seller's level of demand or supply isnt' static. it changes on whims, ideas, guesses, emotions, opinions and etc. if Adam wants to buy widget for $1 but Betty is willing to pay $1.10 for it, and Will has a widget and is willing to sell no less than $1.50 but Yolanda has the same widget is willing to sell for $1.10, then Yolanda sells the widget to Betty for $1.10. Yolanda gets $1.10-broker fees and Betty gets the widget-broker fees. And Adam doesn't get anything and Will still holds his widget. and the broker's board has the last price of the widget as $1.10"], "text_urls": [["http://www.dividend.com/dividend-stocks/services/department-stores/amzn-amazoncom-inc/", "https://en.wikipedia.org/wiki/Amazon_\\(company\\)", "https://www.wsj.com/articles/SB1042311223645379424", "https://en.wikipedia.org/wiki/Microsoft"], []], "score": [9, 5]}}, {"q_id": "7q3y4u", "category": "Repost", "title": "Why does our taste in food change during our lives?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dsm6ov3"], "text": ["It's my understanding your taste buds actually start to fade. When your a child things are that much more intense tasting. As an adult they begin to regress and start dying off. Be interesting to get a real scientific answer though, just something I remembered reading somewhere"], "text_urls": [[]], "score": [8]}}, {"q_id": "7q4mk2", "category": "Repost", "title": "If human cells get changed so often, why do scars retain for a long time?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dsmc28b"], "text": ["Imagine your body as a house where the blueprints were lost during construction. One day, the neighbor's kid manages to smack a baseball through a window. It's pretty easy to tell that there is a shattered window that needs replacement within a window frame even without the blueprints. You get some new glass, install it, and the house looks as good as new. Now, think of the damage if a distracted driver plows a truck though the wall to your living room, taking out a large chunk of wall and an entire window frame. Your first concern is to seal the hole so that the inside of your house is not exposed to the outside. With the hole sealed, you realize that you don't remember what the original wall and window looked like and you don't have the blueprints. You can repair what you can based on the edges but it may look very off both physically and functionally. The seal probably lacks the same insulation and the actual window, but at least nothing can get in or out. This is a scar. Your body only can regenerate (repair back to the new state) parts when it knows what it is based on its surroundings. If it takes too much damage, it won't be able to correctly regenerate and seals it with a scar. The cell replacement acts constantly but can only swap out what is already there. Since there are no blueprints, it cannot make what it doesn't know."], "text_urls": [[]], "score": [5]}}, {"q_id": "7q7dj6", "category": "Repost", "title": "If a person jumped into a hole that began on one side of the globe and stretched to the other side would they fly into the air while exiting the hole or would they land safely on their feet? (Assuming no obstructions in the hole)", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dsmwivx"], "text": ["Neither. Assuming that you ignore the fact that the temperature and pressure in the middle of the earth would kill them, they'd make it most of the way to the other side, but then start falling back down the way they came. They'd get even less close to the entrance where they jumped in, and switch directions again. They'd oscillate back and forth like that for a while before eventually settling into the center of the earth, weightless, and unable to escape without climbing the walls. This is because friction with the air will slow them down during their fall and subsequent ascent."], "text_urls": [[]], "score": [3]}}, {"q_id": "7q9332", "category": "Repost", "title": "When a new tech interface standard comes out (USB 3.1, HDMI 2.0, Thunderbolt 3), what is changed that makes it faster?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dsnbmjv"], "text": ["The protocol on the wire gets changed. Usually a combination of a faster clock rate because of better/faster chips on the interface cards and more efficient methods of transmission. Look at 100mbps fast Ethernet vs 1 gigabit Ethernet. Same cables, but different modulation techniques and thus different speeds."], "text_urls": [[]], "score": [3]}}, {"q_id": "7q9oly", "category": "Repost", "title": "Why does milk help when you eat spicy food?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dsnhnoi", "dsnh5gt"], "text": ["Right! The capsaicin which causes the spicy feeling on your tongue binds with casein in the milk so you don't feel it anymore", "I think the fats in the milk bind the either the chemical that causes the spice, or the nerve endings that would feel it, i kinda forget which."], "text_urls": [[], []], "score": [5, 3]}}, {"q_id": "7qbvlj", "category": "Repost", "title": "Why can't light penetrate walls but radio waves can?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dsnyo8b"], "text": ["It has to do with how EM radiation interacts with materials, and on how that depends on wavelength/frequency/energy of it. Quick little excursion into quantum mechanics. Photons come in discrete packets (quanta), and the energy of the photon determines its wavelength and frequency. The reverse statement is also true, if you have a photon of a certain wavelength/frequency then it must have the corresponding energy. 100 MHz radio means the photons have ~4*10^-7 electronVolts of energy. Red visible light photons meanwhile has an energy about 2 eV. Very high energy gamma rays can push 100 Tera electron Volts. Shorter wavelength/higher frequency=more energy Energy when dealing with subatomic particles is also quantized. Atoms and molecules absorb energy in discrete packets (quanta) and can only deal with energy that comes in packets of the right size. If a photon doesn't have enough energy to cause it's state to jump from a lower energy to a higher energy, it doesn't sit around waiting for another photon to come along and then add the energy of the two photons, it just doesn't interact at all. I should probably mention conducting materials as well. If you have an oscillating electromagnetic field (which is what EM radiation is) near something conductive, you'll find a current develops in the conducting material in response. This takes energy out of the electromagnetic field, reducing the intensity of the radiation. This is how antenna work, but anything conductive in the way will do the same, which is why your wifi is a bit spotty in the bathroom (all those pipes). Radio waves are very low energy. This means they simply fail to interact with most material. It can, but it will take quite a bit of it to do so. While conductive material in the walls will reduce it's intensity, radio waves wavelength can be quite large (that 100 Mhz is has a wavelength 3 meters ) which effectively lets it go around things like concrete pillars with rebar in them, or some pipes. Visible light meanwhile is much more energetic, and can interact with most solid material. So it gets absorbed and either gets scattered off randomly. It just can't make it through. However you can also create situations where radio waves can't get in, but light can. [A Faraday Cage]( URL_0 ) is the classic example. The complete cage of metal bars means it's impossible for radio waves to go around, so it interacts with the metal in the cage, and can't make it through. Visible light meanwhile has a wavelength much much much smaller than the holes in the cage, allowing it to pass right through the holes and never notice the cage is there."], "text_urls": [["https://i.pinimg.com/736x/48/ae/d2/48aed296489ce71da20701f196ec0bb1--military-weapons-scientists.jpg"]], "score": [4]}}, {"q_id": "7qbys6", "category": "Repost", "title": "How does a knife cut through material on atomic/molecular level?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dsnylg8"], "text": ["They push atoms out of the way. I know its a really common fact that atoms never touch eachother, but you have to understand that on the scale that that is true it never ever impacts anything practical. Its like if I showed you a stacked stone wall and said \"here run through this, don't worry, those stones aren't technically connected.\" But atoms are connected on a macro level, and the knife can break these intramolecular bonds as it passes through."], "text_urls": [[]], "score": [5]}}, {"q_id": "7qc022", "category": "Repost", "title": "Why is it you can think of a word and use it properly in a sentence even though you can\u2019t recall what the word means?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dso1unk"], "text": ["Because you've heard or seen it used in that type of context, so you are essentially imitating without understanding. In vocabulary tests, constructing a sentence using a word correctly is taken as a sign that the comprehension of the meaning is there."], "text_urls": [[]], "score": [3]}}, {"q_id": "7qfsx8", "category": "Repost", "title": "What Is the Concern with the Use of Mobile Phones on Aeroplanes?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dsoufqm"], "text": ["There were (are) two main concerns - that cellphones and other wireless devices can interfere with radio communications onboard the plane, and that they can cause interference and confusion within ground network operations. Even though there's no evidence that this has ever happened, the FCC and FAA still preferred to play it safe since theoretically all communications devices involved operate on radio frequencies and that has the potential to cause interference... even though they're at drastically different frequencies. Also there was a time when people considered cellphone usage on planes to be rude, but I think in the last 15 years or so people have given that attitude up."], "text_urls": [[]], "score": [5]}}, {"q_id": "7qlsvz", "category": "Repost", "title": "Why does rapid changing weather cause people to get sick?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dsq6kui"], "text": ["The simple answer to your question is that it doesn\u2019t. There is no evidence that temperature changes make one sick. Instead, people likely make false correlations (X% of people get sick on any given day and some of those days have temperature changes) or other factors that happened with a temperature change \u2014 plants blooming in spring, a cold front that brings new allergens in the air \u2014 are actually a cause rather than the temperature change per se."], "text_urls": [[]], "score": [11]}}, {"q_id": "7qohx4", "category": "Repost", "title": "The differences between Suni, Shia, and Kurdish muslims in the Middle East and the conflict(s) surrounding them.", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dsqp8aq"], "text": ["The Shia and Sunni are the two main branches of Islam, and concern the proper line of descent from Muhammad. The Sunni believe that the rightful heir was Abu Bakr, Muhammad's father-in-law, while the Shia believe it was Ali, Muhammad's son-in-law through his daughter Fatima (hence why the Shia are historically sometimes referred to as the Fatimids, particularly in Egypt prior to the rise of Saladin). In addition to the above, there are also ethnic tensions associated with the Shia/Sunni split, as Arabs (and Muslims in general) are overwhelmingly Sunni, while Iranians are Shia. There are ethnic tensions between the Arabs and Persians/Iranians that date back far before Islam was founded, and that continued into the modern variant that's primarily Sunni Saudi Arabia vs. Shia Iran. The Kurds are a mix of the two (although they are largely Sunni), in addition to other ethnic groups like the Yazidi that are generally held by the Muslim Kurds to be fellow Kurds, and are an ethnic group sandwiched between Turkey, Iran, Iraq, and Syria. Kurds basically want their own ethnic state, and have been oppressed for generations by their neighboring ethnic groups. As a result, Kurds are a bit more nationalistic than religiously-affiliated. The Kurds are also pretty heavily influenced by their diaspora, both in the US and the former USSR, which is part of the reason why they don't generally care as much about religious differences as other Muslim groups in the region. Beyond that, the Kurds are also in a particularly important region of the Middle East that's been influenced by essentially every single Empire in Western and near-Eastern history, including the Persians, Greeks, Romans, Byzantines, Ottomans, the various Crusader States, and the British, Russian, and French empires prior to WWII."], "text_urls": [[]], "score": [3]}}, {"q_id": "7qp6lv", "category": "Repost", "title": "does sleeping late 2am and waking up late noon harm your body and age you prematurely?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dsqv531"], "text": ["The schedule you describe is not that unusual and will not cause you any problems. But living a truly 'opposite' schedule, like people who work a graveyard shift, [can have an adverse effect on your physical and mental health]( URL_0 ) but again, you are NOT at risk for this waking up at noon. You're fine."], "text_urls": [["https://sleepfoundation.org/shift-work/content/living-coping-shift-work-disorder"]], "score": [4]}}, {"q_id": "7qp9gj", "category": "Repost", "title": "what is Escrow", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dsqv7o3", "dsqy6mq", "dsqyc7r"], "text": ["Depends on context, but in general 'escrow' means that a third party holds things and manages the transactions between the two main parties. The most basic example is a mortgage escrow account, where, if the account holder chooses, they can direct deposit a chunk of their wages into the escrow account managed by a bank or similar institution, and the bank handles paying all the bills related to the mortgage, like property tax, the mortgage itself, homeowner's insurance, etc, from the escrow account.", "My bank collects an escrow payment with my mortgage payment each month, and then they pay my property tax and homeowner's insurance when they are due. Instead of having escrow I could choose to just pay these items myself, but that would mean a once-a-year payment of maybe a couple grand I would have to pay out of pocket. I just don't have the discipline to save up for these expenses myself.", "Remember when you were a kid and wanted to trade something with a playmate you didn't quite trust? You'd play this little game where you would try to swap items at the exact same time so no one would wind up with both. If you really didn't trust each other, you might go find an adult who would ensure everything went fairly. Now imagine doing that same thing, but instead of trading a toy car for an action figure, you are buying a house from a stranger. Escrow is that adult, a neutral third party who keeps things fair. You deposit your money, plus a small fee, into an escrow account, where it stays until the house is transferred to you and you agree everything is in order. You can't try to swindle the seller out of the house because your money is already gone. And he can't try to take the money and run and keep the house because he doesn't have access to it. If there is a dispute, the money stays in escrow until it is resolved. Another common use of escrow is when the bank requires you to keep a certain level of insurance in your house while you still have a mortgage. They don't trust you because you could just not get insurance and just declare bankruptcy if your house burned down. And you don't trust them because they could just pocket the money and say \"what insurance?\" if your house burned down. Instead, you put a certain amount away in escrow, and the insurance gets paid out of that."], "text_urls": [[], [], []], "score": [6, 3, 3]}}, {"q_id": "7qpggt", "category": "Repost", "title": "why is there no thunder or lightning during a snowstorm?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dsqx888", "dsr1z8m"], "text": ["I've seen and heard lightning in a snowstorm. Worked at a ski resort as a lift operator, nothing more scary than lightning when you're sitting in a metal shack at the top of a mountain. The weather people call it *thundersnow*.", "It's possible. Meteorologists call it \"thundersnow\", but it's pretty rare. I'm far from a weather expert but I can make an educated guess on why this is the case. Thunderstorms are caused when you have columns of warm, humid air clashing with cooler air. Since hot air is less dense, it rises, forming towering clouds. Daytime heating energizes this cycle, forcing more hot, unstable air upwards. The huge amount of energy in these clouds creates a strong convection current. Any particles within that current will collide building up a static charge, and you get lightning. Winter storms though just don't have that kind of energy. They tend to start life as cooler, dryer air moving across relatively warm bodies of water. They can suck up a huge amount of moisture, but without the daytime heating, there's just not enough energy to create the convection currents necessary to produce lightning. To get thundersnow, you have to have a line of storm cells move over top a layer of cooler air, where precipitation will turn into snow before it hits the ground."], "text_urls": [[], []], "score": [5, 4]}}, {"q_id": "7qq7dq", "category": "Repost", "title": "What is Beta Decay?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dsr2xy2"], "text": ["Yo ho ho! Yer not alone in askin', and kind strangers have explained: 1. [ELI5: Why does beta decay shoot the electron out of the atom instead of putting it to orbit and become a new element? ]( URL_6 ) ^(_5 comments_) 1. [ELI5: Beta decay ]( URL_2 ) ^(_5 comments_) 1. [ELI5:Beta decay, the missing electron ]( URL_3 ) ^(_4 comments_) 1. [ELI5: Beta decay ]( URL_0 ) ^(_3 comments_) 1. [ELI5: How does a neutron release an electron in beta decay? ]( URL_5 ) ^(_5 comments_) 1. [ELI5 Beta particle decay what exactly goes on when this happens? ]( URL_1 ) ^(_2 comments_) 1. [ELI5: what are the differences between Alpha, Beta, and Gamma decay ]( URL_4 ) ^(_4 comments_)"], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/1m9n2c/eli5_beta_decay/", "https://www.reddit.com/r/explainlikeimfive/comments/5xn131/eli5_beta_particle_decay_what_exactly_goes_on/", "https://www.reddit.com/r/explainlikeimfive/comments/soc2b/eli5_beta_decay/", "https://www.reddit.com/r/explainlikeimfive/comments/689swz/eli5beta_decay_the_missing_electron/", "https://www.reddit.com/r/explainlikeimfive/comments/30rh2r/eli5_what_are_the_differences_between_alpha_beta/", "https://www.reddit.com/r/explainlikeimfive/comments/687sn3/eli5_how_does_a_neutron_release_an_electron_in/", "https://www.reddit.com/r/explainlikeimfive/comments/1ny7cq/eli5_why_does_beta_decay_shoot_the_electron_out/"]], "score": [3]}}, {"q_id": "7qtyxh", "category": "Repost", "title": "Why is it easy to stay upright on a bike when moving, but difficult when stationary?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dsru4x7"], "text": ["When moving, the wheels of the bike have angular momentum. Because of the conservation of angular momentum, the wheels want to stay in a particular direction unless a torque is applied. This assists in making the bike dynamically stable (As opposed to statically stable). When not moving, you aren't assisted by anything, so it can be difficult to balance the bike as it is an object with only two contact points with the ground."], "text_urls": [[]], "score": [3]}}, {"q_id": "7qugi9", "category": "Repost", "title": "If the boiling point of water is 100 degrees C/212 F, why do oceans, rivers, lakes etc not have to reach that temperature for clouds to form from them?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dsrxyia", "dsryhli", "dsrxxgb"], "text": ["Water evaporates all the time from the surface of any water body. Boiling is when the whole water body starts evaporating at once, not just from the surface.", "100C = steam. Water can become water vapor at nearly any temperature (vapor != steam) otherwise a puddle would never dry up.", "boiling point means that the average kinetic energy (thats temperature) is above the amount where material goes from liquid to gas. Some water will still be below that energy level, and even if the average isn't up there then some will still have enough energy to undergo that change. So some of it will evaporate naturally, without the whole liquid boiling (its also why your pot of water doesn't instantly disappear when it hits 100 degrees and boils)."], "text_urls": [[], [], []], "score": [8, 5, 3]}}, {"q_id": "7quzkb", "category": "Repost", "title": "How Snap Freezing works?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dss2gta"], "text": ["For water to form ice, it's molecules have to arrange into a crystal lattice form. Being cold can make this possible, but if the water is pure & still, that may not be enough. It also needs a place for the crystals to start forming around. We call this a nucleation site. Water that is cooled below freezing temperature, but hasn't found a nucleation site, is called 'super cooled'. As soon as you give it a nucleation site, by adding something or even just shaking it up, then the ice will form rather quickly."], "text_urls": [[]], "score": [9]}}, {"q_id": "7qy4vt", "category": "Repost", "title": "What is three phase power?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dssuzam"], "text": ["I've searched tha seven seas fer an answer. Yer not alone in askin', and kind strangers have explained: 1. [ELI5 how three-phase power works ]( URL_2 ) ^(_7 comments_) 1. [ELI5: 3 Phase Power ]( URL_6 ) ^(_18 comments_) 1. [ELI5: 3 phase power. ]( URL_0 ) ^(_6 comments_) 1. [ELI5: What exactly are three-phase power systems? ]( URL_1 ) ^(_12 comments_) 1. [Fuckin' three-phase electric power -- how does it work? ]( URL_5 ) ^(_6 comments_) 1. [ELI5 Three-phase power ]( URL_4 ) ^(_8 comments_) 1. [ELI5: Explain 3-phase vs. Single Phase power ]( URL_3 ) ^(_7 comments_)"], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/qy1jt/eli5_3_phase_power/", "https://www.reddit.com/r/explainlikeimfive/comments/6soxfb/eli5_what_exactly_are_threephase_power_systems/", "https://www.reddit.com/r/explainlikeimfive/comments/rh30r/eli5_how_threephase_power_works/", "https://www.reddit.com/r/explainlikeimfive/comments/1jfywb/eli5_explain_3phase_vs_single_phase_power/", "https://www.reddit.com/r/explainlikeimfive/comments/nlsx8/eli5_threephase_power/", "https://www.reddit.com/r/explainlikeimfive/comments/le3nx/fuckin_threephase_electric_power_how_does_it_work/", "https://www.reddit.com/r/explainlikeimfive/comments/4nzw1r/eli5_3_phase_power/"]], "score": [3]}}, {"q_id": "7r4ty6", "category": "Repost", "title": "How can hot water freeze faster than cold water?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dsu8hu1"], "text": ["Hot water loses heat at a faster rate than cold water but it doesn't freeze faster. Heat lose has an aspect of temperature difference in the equation (Q=mCp(T1-T2)) so the rate of heat loss is faster with a bigger temperature difference. Hot water from a tap does hold a lot more metal from the pipes (which is why you aren't supposed to cook with it). Metal ions in water provide a surface for the water to crystalize on, making the freezing process easier. Thats more related to where the hot water came from though than the fact that it was hot (at least not directly). EDIT: if you boil water and toss it into the air it will spread out and evaporate. once the mass of water is small, the rate at which it freezes goes up. A sitting pot of hot water will not freeze faster than a sitting pot of cold water."], "text_urls": [[]], "score": [4]}}, {"q_id": "7r53vv", "category": "Repost", "title": "Elon Musk's belief that we are likely computer simulations", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dsuapq7", "dsud0sf", "dsucjd5", "dsua3b7", "dsuddwl", "dsud0jt", "dsudlv4"], "text": ["Basically that as technology progresses, not only do things become more and more realistic, but that the users become more and more embedded in the experience (thing virtual reality and augmented reality). Elon suggests it's possible that humans became so advanced with hyper realistic virtual reality that we are not the users ourselves, but instead are the characters in a simulation and that the feeling of \"reality\" is incredibly well crafted. I don't think he *believes* this, though, but rather offers it as a theory to explore. Edit: apparently he does, in fact, believe it, as per a few correcting comments below", "Elon Musk's belief that we are likely in a computer simulation requires just two assumptions. 1) \"Virtual reality\" indistinguishable from \"actual reality\" is possible. We know that human beings experience things through sensory inputs that can presumably be manipulated with advanced enough technology. 2) If there is only one base \"actual reality\" the number of \"virtual realities\" that can exist in the universe at any given time is much higher. If there are 20 hyper-realistic indistinguishable VRs and only 1 actual reality, we are 20x more likely to be in VR than actual reality. If you hold the above assumptions to be true, it's pretty hard to challenge the logic strictly on a philosophical or mathematical level.", "We are at a point where we can run some pretty intense simulations and we've only been computing for a few decades - think where we'll be in a century or two. It's conceivable that we could create a simulated world filled with self-aware AIs who feel a very real existence. Assuming that's possible, what are the odds that we're the first to think of it? Going off on a tangent, there's an episode of Rick and Morty that explores this idea. Rick has a battery powered by a micro-universe inside it, filled with people generating power that he syphons to power his car. When the battery stops working, he goes inside this world and finds that a scientist in this world has created a new battery-universe, unaware that he is himself living within one.", "I think this one would be easy enough to google and easily comprehend, I'll link a video that I watched and thought was really good in a sec. Edit: Link - URL_0", "It's an interesting bit of speculative logic. Here are the points you need to buy into: 1. Technology will continue to improve. Note that it does not have to improve at the same rate as now. 2. A technological civilization can survive. 3. A technological civilization will remain curious 4. Self-aware A.I. is possible. If you buy into all four of those things, then at some point a technological civilization will be capable of running a large number of simulations including self-aware A.I. Now the question is: are we in the one true universe or are we in one of the many, many simulations? Considering that there is only one chance for this to be the real universe, it's much more likely that we are in one of the simulations. As an interesting aside, some people have theorized that the fuzzy nature of physics at the quantum level might indicate a kind of optimization similar to the kinds of optimizations we already make in our simulated MMO games.", "For Elon Musk himself, he's probably on some sort of drugs, heard it, and thought it sounded cool. But let's consider the general argument. Let's say it's practical, in some universe, to simulate a reality using computers. (This can be done, it's just prohibitively expensive in our laws of physics.) So someone, for some reason, in that universe, decides to simulate a reality. And that reality is capable of creating people. If you're a person and you know that this happened and that's it, you might reasonably assign a 50% chance of you being in a simulation. Now, if one person can do this, probably many people can. So the odds are much higher than half that you're in a simulation. To take it further, in one of those simulations, someone builds a computer capable of simulating another reality. And similarly, once one person does it, many people can. So this multiplies the number of simulations by a large factor. But wait, we can apply the same process to the simulations inside the simulations! So now there's a stupendous number of simulated universes. What are the odds that yours is the one on top? Very low indeed. There are some problems with this, but that's the basic idea.", "Yeah but have you gotten to play Second Second Life? I know a pretty good paper salesman there."], "text_urls": [[], [], [], ["https://youtu.be/tlTKTTt47WE"], [], [], []], "score": [91, 21, 15, 5, 5, 4, 3]}}, {"q_id": "7r6s6o", "category": "Repost", "title": "Stainless Steel is hard. Meat is soft. You take a stainless steel knife that is very sharp and start to cut meat and the knife gets blunt very fast. Why? How can something so soft destroy the sharpness of stainless steel or other metals?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dsunb0f", "dsunjka"], "text": ["I sold cutco knives for a brief period of time so I actually know the answer to this. The answer is that very little food actually dulls your knife. It's usually your cutting board. Wood, plastic, stone, ceramic. All of these dull your knife edge very quickly. The \"trick\" to cutco knives is that the actually cutting part never makes contact with the cutting board.", "Part of it is that the ultra-thin edge gets *folded over,* rather than actually blunted. Even a soft (but dense) material can do that."], "text_urls": [[], []], "score": [6, 3]}}, {"q_id": "7r9cz9", "category": "Repost", "title": "How can we \"hear thoughts in our heads when we can't physically hear them ears?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dsv5fsb"], "text": ["One of the nice features of the brain is it's ability to simulate things, benefit of the frontal cortex. This helps us do a lot of things like not touch the stove (that would hurt, my skin would sting) hang out in public bathrooms (smells like pee, I don't like that), and hear our thoughts before we voice them. It's been suggested that this helps us organize our thoughts, similar to talking out loud. There's a popular technique for problem solving called the rubber ducky method, where you explain your thoughts to an inanimate object like a rubber duck out loud to better think through a problem. It's like your friend asking you for help on a physics problem and explaining it, only to get it before he gives you the chance to try. Source: took psychology last semester"], "text_urls": [[]], "score": [29]}}, {"q_id": "7ra2bh", "category": "Repost", "title": "Why are cryptos primarily(always?) mined using the GPU?", "title_urls": {"url": []}, "selftext": "This specific question came to mind, but it also solidified the thought in my mind that I don't really understand how a CPU/GPU works and its primary function. Hopefully I can give some more context through some other questions I have, in turn giving more insight to where this question is stemming from. So, why are cryptos primarily mined using the GPU, but what does that say about the CPU; why is a GPU more efficient at these computations? What specifically is GPU designed for(Image processing?)? Image processing, but what exactly does that process look like? What steps are taken on the path of processing an image? Both virtual steps and physical steps. How does that process correlate to coin mining such that it is more efficient to mine via the GPU? Does it have to do with registers? Is a register simply a different piece of memory? just closer(easier to access) than RAM? What path would the computation take if the CPU were processing it vs if the GPU were processing it?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dsva9kt"], "text": ["TLDR: Cpus run your computer, and thus have to be able to do a lot of things well at the cost of speed. GPUs are mostly just process graphics, which is mostly a monotone process. As such they are built to do few things incredibly fast. CPU are masters of general logic. They can do a lot of different things very well, and as such are great at running your computer and general purpose computing. GPU's are designed to do one thing very very well: repeated calculation. Their intended purpose is processing graphics which involves a whole lot of doing the exact same calculation over and over and over. Most of graphic processing is just built on linear algebra and a whole lot of matrix multiplication. They are thus optimized to be able to calculate a lot of similar things in parallel using multiple cores. Because cryptomining is just running a hashing function again, and again, and again, until you find an answer GPUs are a prime candidate (aside from single purpose CPUs) for mining. Their entire purpose is to calculate a lot of things fast."], "text_urls": [[]], "score": [11]}}, {"q_id": "7rbtdo", "category": "Repost", "title": "the 4th and 5th dimension", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dsvpcgj", "dswa1gm", "dswc06g"], "text": ["Imagine a new type of people that only exist on a piece of paper in two dimensions. They can go left and right on the paper and up an down, but they cannot go past the paper. They only exist in 2 dimensions: up/down and left/right. Now if you were to show them a ball, they wouldn't be able to even fathom a ball. At best, they would be able to see a rapid series of circles coming at them getting larger and then smaller as the ball goes past. Now you exist in 3 dimensions, but the 4th and 5th would be similar to you as the ball is to a flatlander. We can explain the dimensions with math, but we can't experience them. Our brains are simply designed to operate in 3 dimensions and not more. Additionally, some people refer to time as a 4th dimension, but since I assume you actually meant spatial dimensions, so that is what I explained it as.", "URL_0 Carl Sagan is really good at explaining things.", "Imagine a line. A line is one dimension. Now how do we make this a square? We tilt it up on its side while leaving the first one behind and finish the other two lines, now we have ourselves a square. How do we make a square into a cube? We turn it on its side, finish the other 5 lines. Now we're in three dimensions and have a cube. How do we get to four dimensions, a hypercube? Well, when we look at a line and a square, the square can be gotten by \"popping\" the line sideways into two dimensions, and the cube from the square can be gotten by \"popping\" the square up and into three dimensions. So, it makes sense, for us to get to the fourth dimension we need to pop the square... in what direction? This is the constraint of our third-dimensional thinking. In what direction do we pop out? There are two ways of thinking about this. One is that there is that there's some unseen direction (that for the most part, I visualize as diagonal when needed) and we simply turn the cube on its side in four dimensions and connect the other 20 lines, creating a hypercube. Continuing this process for a hypercube, we get our fifth-dimensional cube or penteract. The other is that the fourth dimension is time. Suppose there was a world working in two dimensions on an infinitely wide plain and you pass a sphere through it, from their perspective, they see a circle appear, get wider, smaller and eventually disappear. Now imagine the sheet is blank and you pass through an extremely complicated spiral thing, and from the 2d perspective, it's playing like an animation, going through a universe. Every instance is in this 3d shape but the 2d people can never experience it. This 3d object shifting shape as it passes through becomes time. Now imagine the same for a four-dimensional object going through our space, we see a collection of 3d space moving around, but 'time' is just the shifting of this four-dimensional object. Puts you into perspective, doesn't it? All that being said, I'm no expert, but that's my take on it all. And as has been mentioned, we can explain these dimensions mathematically but our minds can't experience them."], "text_urls": [[], ["https://www.youtube.com/watch?v=N7K5KjOdLD8"], []], "score": [94, 12, 5]}}, {"q_id": "7rcgxi", "category": "Repost", "title": "How does everyone have a different voice?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dsvu3zt"], "text": ["The shape of everyone\u2019s vocal chords are different. This effects how frequencies are produced. Every trained singer can sing the same note, but we can\u2019t produce a pure sine wave that is exactly one frequency. Instead we produce a note that has a specific base frequency and then based on the shape of our vocal chords and some other factors we also produce additional frequencies at varying levels. This gives us our unique voice and is also the concept that makes a trumpet sound different from a piano or a flute. Google frequency graphs of \u2018overtones\u2019 for more information."], "text_urls": [[]], "score": [3]}}, {"q_id": "7rdqva", "category": "Repost", "title": "What is fantasy football and how does it work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dsw4ltl"], "text": ["In a nutshell, people get together and make up imaginary \"teams\" composed of actual NFL players. There's usually some sort of imaginary budget, a mock draft to choose players, etc. Statistics for those players serve as the basis for scoring how well your players are doing each week. Typically people who get together to form a fantasy league charge a fee which goes towards some sort of prize for the winner after a season. All in all it's just a fun way (for some) to stay interested and engaged in the sport as a whole."], "text_urls": [[]], "score": [3]}}, {"q_id": "7rfkht", "category": "Repost", "title": "- How can I regulate my entire body's temperature by sticking my foot outside of my bedsheets?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dswjltg"], "text": ["It's like a heat sink on a cpu. Blood there exposed to cooler air cools your blood. This cooler blood circulates in your bloodstream cooling your body. New warm blood pumps into your foot cooling it a little bit more"], "text_urls": [[]], "score": [5]}}, {"q_id": "7rgtdj", "category": "Repost", "title": "Why do our joints and bones hurt when the wearther is changing?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dswsskl"], "text": ["Changes in weather are accompanied, and in fact usually preceded, by changes in atmospheric pressure. Changes in atmospheric pressure affect the fluid pressure in your joints. Changes in fluid pressure in your joints hurts."], "text_urls": [[]], "score": [8]}}, {"q_id": "7rha9b", "category": "Repost", "title": "when you're ill, why do you feel the worst in the morning and better throughout the day?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dsww9ew", "dswvrt1"], "text": ["Being horizontal and immobile allows a lot of buildup of goop, so for instance the back of your sinuses and your throat get coated in an extra thick layer of old dry mucus, making any cough or laryngitis worse, as well as keeping your lymph nodes from draining well, causing additional swelling. You just fasted for 8 hours, you're dehydrated and hungry. Most symptoms of illness are actually things your body is doing to itself to keep the illness contained. When you're asleep your body does them harder because you aren't doing anything. Your immune system responds to you doing things or not and cranks up or down your symptoms to match; for instance you may notice that if you start working hard on something physically intensive you stop producing as much mucus, you stop feeling as achy, and lymph node swelling goes down as your immune system slows down, but other symptoms like headaches get worse because you're not containing the illness as well anymore.", "Maybe because you're at your most dehydrated and malnourished when you wake up?"], "text_urls": [[], []], "score": [6, 3]}}, {"q_id": "7rjrif", "category": "Repost", "title": "how do we know the calculation of pi number is correct?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dsxekdk"], "text": ["Most approached for calculating pi are series expansions that have mathematical proofs of their equivalence to pi. [This great Wolfram Alpha page]( URL_0 ) explains the most common formulas and cites their discoverers."], "text_urls": [["http://mathworld.wolfram.com/PiFormulas.html"]], "score": [3]}}, {"q_id": "7rlx3o", "category": "Repost", "title": "is the concept of light speed defined by light itself, or does light just want to go infinitely fast but physics puts a cap on it?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dsxxbxj", "dsxwzeb", "dsy0146"], "text": ["As far as we know, it's the second one. Particles with no mass travel as fast as physics allows anything to travel. Since photons are the massless particles that we encounter most often, we first encountered that maximum speed by observing light and we called that speed \"the speed of light\".", "Light is fast, way faster than most people can even imagine, but thankfully our measurements are very precise as well, so we are able to measure it very accurately (First done by Fizeau and Focault in 1830ish, not like /u/ganganinja claims by sending lasers to the moon, we do that to measure how far the moon is away, knowing how fast light is and then measuring the time). Light, sadly, is not infinitely fast, it is actually very, very, very slow compared to the size of the universe, even the closese star is lightyears away form us, meaning that the light you see when looking up at the sky and seeing all those small little bright spots has taken millenia (and often way, way, way, way, way, and i mean like way way way, longer than just a few millenia, wich is basically no time, to be honest), to get from the star that emitted it to us here on earth. I would also like to add that in fact these days we dont measure the speed of light at all, in the 1980s we just agreed on the speed of light as a certain number (exactly 299,792,458 metres per second) and are now using that number as the basic measurement for everything (so if you know how long a metre is you no longer go to baris and look at that stick napoleon made and about wich he said \"this is a metre, and any metre on earth is defined by beeing exactly as long as this stick\", you instead take the distance for wich a beam of light needs exactly 1/299,792,458 seconds to travel it)", "Watering it down, a lot, light is a wibble in the em field. Sound moves at different speeds through air, or helium, or steel essentially because of atoms knocking into each other. So basically energy take time to transfer through the material. Even light! Because its just a wibble in the EM field. If you were to shine a light next to a steel beam while passing electric current through the beam, the light would arrive *just* ahead of the electric current. The energy took longer to travel through steel than free space. Suppose you wanted to travel faster than sound, what happens? You move faster through the air than the air can transfer the energy of the sound you make. It stacks up and you get a boom, all the sound at once. What happens when you toss a light speed particle at steel(which it should travel slower through, electric current is a wibble in the EM field too), what happens? Well, again really watered down, the energy stacks up and you the excess energy gets released as [Cherenkov radiation]( URL_0 ). A light boom! Ok so TLDR whats this all mean? Light can travel slower through a material. But in free space, a vacuum, it travels as fast as energy can be transferred through the EM field. You can't travel faster than C because youd outrun the fields holding you together."], "text_urls": [[], [], ["https://en.m.wikipedia.org/wiki/Cherenkov_radiation"]], "score": [6, 4, 3]}}, {"q_id": "7rmj2s", "category": "Repost", "title": "How do microwaves not heat up plastic and ceramic dishes?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dsy1ni3", "dsy13yb", "dsy3faa"], "text": ["Microwaves excite water molecules and make them vibrate, there are no water molecules in plastic or ceramic.", "Those substances are transparent to light at microwave frequencies. It's like how light can go through a window and warm up the cat.", "It all has to do with polarity of the molecules. Microwaves work by emitting microwaves in alternating directions which causes the polar molecule to move slightly. Since this happens so fast the molecules look like they are vibrating and this vibration heats up the molecule. This is why a polar molecule like water will heat up. Molecules that are not polar like plastic, ceramic, oil, etc don't move or vibrate which means they won't heat up. You can test this out by putting a small cup of olive oil in the microwave. It isn't going to heat up and you will be amazed."], "text_urls": [[], [], []], "score": [5, 3, 3]}}, {"q_id": "7rmup7", "category": "Repost", "title": "why is it that cameras cannot take a clear picture of an LCD screen?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dsy3r9k"], "text": ["Monitors and TVs typically have a set refresh rate - 50Hz and 60Hz are fairly common. This means that the screen is redrawn around 50 or 60 times a second. To the human eye, this looks smooth - it's fast enough to be almost unnoticeable. Cameras, though operate differently from our eyes. If the frame rate of the camera matches the refresh rate of the screen you're looking at, it'll probably look fine. Usually, this isn't the case. The camera then could capture a partly drawn screen as one of it's frames, and then capture a different part of the screen in the next frame, etc. Net result: it looks like it flickers (or you see moving black bars), since it does this very quickly. The black bars are a slightly different story from the flickering - the issue there is called aliasing. It's the same reason why if you film a wheel moving at the right speed, it can look like it's spinning backwards. If you think of video cameras as just taking a lot of pictures really fast, the way we perceive motion in a video is that you assume things move the smallest amount possible. So if a wheel has 8 spokes (evenly spaced, 360/8 = 45 degree separation) and rotates 35 degrees between frames, you'll probably think it took the shortest possible rotation - 10 degrees in the opposite direction (this breaks down if the spokes are distinguishable). The black bars you make see on some cameras are the same effect - the camera captures snapshots at different points in time that make it look like the bars move in a way vastly different from the actual scanning of the screen."], "text_urls": [[]], "score": [9]}}, {"q_id": "7rt5sp", "category": "Repost", "title": "What's the practical application of imaginary numbers?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dszezz8"], "text": ["They're used in a lot of math that has real world applications since they can be used to denote the x and y axes of a sinusoidal function. For example the function F = cos(theta) + i sin(theta) has tons of practical applications in electric circuits, mechanism analysis, and in a fluid analysis technique called potential flow. The details of these applications are quite a bit beyond ELI5 though. Just know that the equation I posted above is super useful in many fields."], "text_urls": [[]], "score": [3]}}, {"q_id": "7ru2k4", "category": "Repost", "title": "if human skin cells reproduce and you essentially have different skin than you did 5 years ago, why do scars never disappear?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dszl8si"], "text": ["From what I understand scars are made of collagen fibres, and when the layers of skin move from the deeper layers to the surface to eventually be shed it simply moves around this different structure of collagen fibres (the scar) instead of eventually shedding the scar as well"], "text_urls": [[]], "score": [4]}}, {"q_id": "7ru9jz", "category": "Repost", "title": "What is the source of heat for the Earths core?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dszmckf", "dszniyv"], "text": ["> What is the source of heat for the Earths core? A small portion is residual heat from the initial collapse of material into the gravity well of Earth, but the majority at this point is from radioactive decay of heavy elements in the core.", "The majority comes from radioactive decay. There are various elements in the core which are not stable; slowly, over time, they decay into lighter, more stable elements. This doesn't produce much heat per volume, but that heat has nowhere to go; the crust makes for a very effective \"blanket\" to keep that heat inside. That, combined with the sheer size of the planet, means that the core is hot enough to be molten (though the core itself is solid due to pressure). Other sources of heat include the residual heat from Earth's formation and tidal heating from the moon. For tidal heating, note that the moon doesn't pull all parts of Earth equally: the side closest to the moon feels the moon's gravity slightly stronger than the side farthest away. This leads to Earth squishing a bit (and water sloshing around a bit--tides!), which means some friction internal to the planet. Some celestial bodies feel this effect so strongly that it is sufficient to melt their core on its own; Jupiter's moon Io is a notable case of this. The relative size, distance, and mass of the moon means that it wouldn't be enough to keep Earth's mantle molten on its own."], "text_urls": [[], []], "score": [6, 5]}}, {"q_id": "7rwxvd", "category": "Repost", "title": "How is Water a liquid?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dt08g4n", "dt08hpd", "dt0aaln"], "text": ["Water is liquid because of polarity within the molecules, and hydrogen bonding between the molecules. These two factors promote attraction between molecules. HCl and H2S don't have as much attraction between molecules, so they become gases more easily.", "One of the properties of water that makes it really fascinating chemically is the strength of all the hydrogen bonds that can be formed. The oxygen in water is slightly negative and the hydrogens are slightly positive. The attraction between a slightly positive hydrogen in one water molecule and a slightly negative oxygen in the next water molecule encourages all the water molecules to arrange themselves close to each other and form a network with all the slightly positives pointing towards a slightly negative. Bringing the molecules closer together and forming that network makes liquid water more stable than other states at ambient temperatures and pressures.", "It is actually a very good question. Water is a bit of a 'special' molecule/material as a handful of its properties are unintuitive. A lot of the special behaviour is because water molecules act like tiny little magnets. This is not unique in chemistry by far, but water has the nice combination of being small _and_ a relatively powerful magnet. These magnet-like interactions are called _hydrogen bonds_ and act in a way to keep the water molecules together stronger than just the 'normal' matter interaction that you see for most stuff. The stronger molecules stay together, the more energy is required to pull them apart and go from solid - > liquid - > gas. The same way that stronger magnets need more energy to be pulled apart than weaker magnets. As a side note; hydrogen bonds are also very common in biochemistry. In fact, it are hydrogen bonds that keeps your DNA-stands together."], "text_urls": [[], [], []], "score": [12, 3, 3]}}, {"q_id": "7rzy8a", "category": "Repost", "title": "I get why we as humans need to feel pain, but why can't we control our brains to lessen the pain after we're aware of the wound?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dt0uig3"], "text": ["There's no particular advantage beyond your personal comfort, and a lot of potential disadvantage, like the ability to ignore injuries. You being comfortable isn't especially important to your survival or reproductive fitness. But being aware of injury, as well as restrained from continuing to aggravate injuries, is incredibly important. So there's no particular selective pressure to let you 'reduce the feeling of pain' and probably a fair amount of pressure to *not* let you do so."], "text_urls": [[]], "score": [10]}}, {"q_id": "7s165g", "category": "Repost", "title": "Why is polygamy illegal?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dt15d0h", "dt15dne"], "text": ["What laws make it illegal to be in a polyarmorous relationship? There are laws against getting legally married to multiple people, though that is more due to the potential for legal issues such as taxes or estates.", "The Eighth Amendment to the United States Constitution prohibits the imposition of cruel and unusual punishment."], "text_urls": [[], []], "score": [11, 4]}}, {"q_id": "7s4rqe", "category": "Repost", "title": "What's the difference between a game designer and a game programmer?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dt1zb42"], "text": ["> I've decided to study degree in gaming, however i'm confused whether to study game designing or game programming. \"Gaming\" is playing games. You don't want a degree in playing games, you want a degree in making them - i.e. a degree in game _development_. > I've some ideas and concepts of creating new video games. That's a design thing. > In order to execute those ideas, can I do that while being a game programmer or I must be a game designer to carry forward those ideas? The game designer has the ideas. The game programmer writes the majority of the code that powers the game, which includes tools for scripting. The game designer will do the scripting. So a game designer is an ideas person who does a bit of programming to e.g. implement abilities. A game programmer does the programming that enables scripting, as well as all the other programming - networking, rendering, etc. Before you decide what you want to do, head to /r/gamedev and read as much as you can. Check out their sidebar & wiki. EDIT: I thought I'd describe a scenario. Dan is the game designer. Petra is the programmer. Dan wants to create a team-based PvP hero shooter, because he thinks Overwatch is garbage. So Petra goes and spins up Unreal Engine, and starts writing code to govern things like networking and UI. Dan says: \"I know! We'll have an archer hero who has a one-shot ability on a short cooldown!\" He goes to the artists, who make some rigs and animations for him. Now he can create his new hero! He sits down with the tools Petra has written, and writes some code in a language like Lua that connects the character model with some code that handles projectiles. But then he realises he wants the arrows to be able to split on impact. The scripting language can't quite handle that. So he asks Petra to make some changes to the engine so that he can script projectiles that mutate on impact."], "text_urls": [[]], "score": [7]}}, {"q_id": "7s4w0s", "category": "Repost", "title": "Why is it greenscreen and not any other color? and how does it work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dt1zvki", "dt204it", "dt219zz"], "text": ["It can be any colour you want. But you have to pick a colour that will not clash with the rest of the set, or the costumes of the actors. There has to be a decent contrast between the screen and the rest of the set.", "It's because green is a very avoidable colour. You can practically use any color instead of green, but green is the easiest to leave out of your wardrobe.", "Long story short: Computers still aren't nearly as good at 'vision' as humans are. Seeing things, knowing what they are etc. Things like looking at an image and differentiating the background from the foreground are not trivial problems for a computer, like they are for your eyes. This is because you think of things in terms of shapes, concepts, and a pre-defined set of knowledge about the world around you, which often lets you decide what something is, or is not, or where it begins, or where it ends, or what it's shaped like (these assumptions let you process things fast - but of course can sometimes be [wrong]( URL_0 ) which is hard for the mind to process). Computers, on the other hand, think of images in terms of millions of tiny triangles with particular properties. Colors being similar in the foreground/background, things blending or facing, shadow and light etc all confuse a computer as to where one object starts and the next ends. For a human to correct a computer on these mistakes is very tedious and time-consuming. So, instead, we help the computer which is editing the movie to know what's going on. We take everything which will not end up in the final movie ( props, the background, the arm of that one character who is supposed to have a machine gun for a limb) and we make it one solid, [uniformly lit]( URL_1 ) color. Then, when we edit the movie, it's much easier for the computer to know what the 'background' is or what the 'props' are without us having to tell it for every single frame, and from there we can do the rest of our editing work -e.g. drawing animations or CGI onto the background - much more easily."], "text_urls": [[], [], ["https://cdn.list25.com/wp-content/uploads/2011/11/217.jpg", "https://www.videomaker.com/sites/videomaker.com/files/styles/vm_image_token_lightbox/public/articles/17026/321-C10-Basic-Training-SECONDARY.png?itok=cRAqYrT2"]], "score": [6, 3, 3]}}, {"q_id": "7s76m8", "category": "Repost", "title": "What are the floating light things if you look at a bright light or press on your eyes hard enough?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dt2gv9r", "dt2hoey", "dt2kxbg"], "text": ["The structure of the gel that fills the eye can have tiny imperfections which you notice as floaters when they cast a shadow on the retina. This is nothing to worry about and can increase with age.", "Are you talking about floaters or the \u201cdark\u201d spot that appears on the opposite side of where you\u2019re pushing?", "I know someone else already mentioned the floaters, but if you close your eyes and apply pressure you'll see light. This is because the eye doesn't have any pain receipts but can still sense pressure, so it tells the brain how much pressure it feels via seeing light."], "text_urls": [[], [], []], "score": [5, 3, 3]}}, {"q_id": "7s7bc1", "category": "Repost", "title": "Why is Citizen Kane always referenced as the epitome of film making?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dt2ide5", "dt2lvsy", "dt2i8ww", "dt2i65j"], "text": ["There is a tremendous amount going on in that film. Aside from being written and directed by its star (Orson Welles), it's also a technical masterpiece, and it uses its technique to enhance the telling of the story. Nearly all of the shots in the film feature 'deep focus', where the background and foreground are equally in focus; this requires enormous amounts of light and special lenses, but it gives an amazing effect. You can see how it is used to enhance the themes of the story at several points, most notably the scene where Charles is informed that he has lost his fortune - as he moves to the back of the room, he appears to physically shrink as his ego is diminished. The film uses every form of animation that had been developed to that point, also a big technical deal at the time. The peeling of the layers of the mystery is also particularly masterfully done. I'm really just touching on the surface of it, though. It's too much to relate in an ELI5, but I tried to hit the high points. If you can, I *very* highly recommend listening to Roger Ebert's commentary on the DVD and Blu-Ray release of the film. Just that one two-hour commentary is like a Master Class in filmmaking, and really gives a very complete explanation of your question. I hate to pawn off an explanation like that, but Ebert explains it so much better than I ever could. Before watching it with his commentary, I had the exact same question you do, but by the end I *absolutely* understood.", "Ahoy, fellow redditor. Yer not alone in askin', and kind strangers have explained: 1. [ELI5 - Why is Citizen Kane considered to be the pinnacle of movie making? ]( URL_4 ) ^(_68 comments_) 1. [ELI5: What is the big deal about Citizen Kane? ]( URL_1 ) ^(_3 comments_) 1. [[ELI5] Why Citizen Kane is often regarded to be the best film of all time? ]( URL_5 ) ^(_11 comments_) 1. [ELI5: Why is Citizen Kane considered one of the best movies of all time? ]( URL_0 ) ^(_31 comments_) 1. [ELI5:Why Is Citizen Kane Considered The Greatest Movie Ever Made ]( URL_2 ) ^(_7 comments_) 1. [ELI5: Why is Citizen Kane notable? ]( URL_6 ) ^(_5 comments_) 1. [ELI5 Citizen Kane is such a big deal in film. ]( URL_3 ) ^(_8 comments_)", "It set up filmmaking up as a study of the human condition, previously a territory largely held by novels. It also raised the bar extremely high as far as editing, writing, acting, etc. While many of the features you see in Citizen Kane are commonplace in films today, in 1941 this was not the case. Citizen Kane really defined what movies could and should look like.", "It did a couple of things that were never done before in terms of camerawork, editing, music, storytelling, etc. It was essentially a decade ahead of the films of that time and even ~80 years later no film has ever come close to the same type of perfection and innovation as was seen in Citizen Kane."], "text_urls": [[], ["https://www.reddit.com/r/explainlikeimfive/comments/20bl3r/eli5_why_is_citizen_kane_considered_one_of_the/", "https://www.reddit.com/r/explainlikeimfive/comments/1qw6dk/eli5_what_is_the_big_deal_about_citizen_kane/", "https://www.reddit.com/r/explainlikeimfive/comments/2znkvf/eli5why_is_citizen_kane_considered_the_greatest/", "https://www.reddit.com/r/explainlikeimfive/comments/mqigk/eli5_citizen_kane_is_such_a_big_deal_in_film/", "https://www.reddit.com/r/explainlikeimfive/comments/61dbl4/eli5_why_is_citizen_kane_considered_to_be_the/", "https://www.reddit.com/r/explainlikeimfive/comments/wm4wo/eli5_why_citizen_kane_is_often_regarded_to_be_the/", "https://www.reddit.com/r/explainlikeimfive/comments/17tvpk/eli5_why_is_citizen_kane_notable/"], [], []], "score": [7, 5, 4, 3]}}, {"q_id": "7s9s82", "category": "Repost", "title": "Why is there an imprint left on your eye after looking at a light source?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dt38zau"], "text": ["There are cells sitting on the back of your eyes (called retina) and they kind of \"read\" the information (light) falling onto them trough your pupils. When light shines on them, they get activated and send tiny electrical signals to your brain, which in turn translates them to a picture you can \"see\". So when you look at a light source, your cells get too much information/get overactivated and after you close your eyes they still send those tiny signals to your brain, hence you still see a shape. This afterglow however stops rather quick, as the cells soon stop \"firing\" signals due to the lack of light or as they get new information (different light/colors/shapes...)."], "text_urls": [[]], "score": [3]}}, {"q_id": "7safio", "category": "Repost", "title": "If All Countries Are In Debt, Who Do They Owe?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dt38gk5"], "text": ["Think of a country's debt in the same way as personal debt. An average person might be in debt for: * A mortgage * A car loan * Student loans * Business loans/Startup loans * Credit Card And any number of other debts, usually to banks or other financial institutions. If you look at that balance sheet, my imaginary person is certainly tens or hundreds of thousands of dollars in the negative, when you compare their debts to their assets (savings + property). But is that a bad thing? Not necessarily, because they're paying back those debts as promised, and they have enough extra money after paying those back to live on. Think of a country's debt the same way. They can keep spending money because nobody's asking for all that debt to be paid back right away, it's being paid back over time, or cashed out at a later date. And most countries in the world are able to do that while still spending what they have to spend (government employee wages, infrastructure like roads, bridges, benefits like Social Security or healthcare, etc). And for most of those countries, a huge chunk of their debt is owed to their own citizens. Anyone who has a government pension, anyone who's taken out a federal bond, etc. is owed a part of that national debt. And most of it is earmarked, saying \"pay out in 10 years\" or \"pay X per month for Y years.\" So even when a nation is trillions of dollars in debt, as long as people are being paid as they expect, and the country is able to meet its obligations, the debt itself isn't a problem unless it's growing too fast to be managed."], "text_urls": [[]], "score": [3]}}, {"q_id": "7sambu", "category": "Repost", "title": "How did \"Southern Gentlemen\" of the 19th and 18th centuries procure and keep ice for their Iced Tea?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dt39rc7", "dt3bn0m", "dt39unq", "dt39unc"], "text": ["Cut a big block of ice out of a lake in the north of the country, and have it carried to you in the south before it melts. If you get enough big blocks and stick them in a cellar there will be some ice all year.", "My grandfather was an ice man. They used to cut giant blocks from the lake I grew up near, store them and ship them. Had underground storage dug near the lake.", "There was once a huge industry in the north that would cut tremendous blocks of lake ice, and store it packed in hay or straw in an *icehouse*. [Read more about it]( URL_0 ). It was shipped wherever there was demand.", "They harvested ice and floated it down river or by sea and stored them in ice chests generally made of ceramic and metal. [No really]( URL_0 )."], "text_urls": [[], [], ["https://en.wikipedia.org/wiki/Ice_trade"], ["http://mentalfloss.com/article/22407/surprisingly-cool-history-ice"]], "score": [7, 5, 4, 3]}}, {"q_id": "7sgovp", "category": "Repost", "title": "How can a tiny microSD card have so much storage compared to a hard drive which is typically much larger?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dt4lnds", "dt4la7w"], "text": ["MicroSD cards are more expensive per GB, and have a lower transfer speed. I just quickly googled the price of a 4TB Western Digital Red hard drive. Those can read/write at around ~340MB/s and costs about $160, for a cost of $40/TB. Compare this to a SanDisk Ultra 128GB MicroSD card. Cost is $60, meaning that it is $480/TB (12 times as expensive), and has a read/write speed of about 10MB/s. MicroSD cards have physically smaller storage, which costs more to make, and takes longer to read/write. It's a trade-off for the form factor.", "Keep in mind that bigger hard drives are much faster thsn microSD! Also SSD's are getting smaller and more dense. The actual data storage in hard drive is not that big. But there are other mechanisms that allow writing on fast moving plate. Also the housing sizes are somewhat standardized. Some people say that HDD is obsolete technology, they are right, SSD is going to replace that very soon. But HDD is so advanced and refined technology and best capacity per price right now. You could likely make a circuit with dozens of microSD slots and cram loads of cards in same space as 3.5\" HDD and likely exceed the capacity. But speed and other performace parameters would be worse."], "text_urls": [[], []], "score": [8, 3]}}, {"q_id": "7sm3xa", "category": "Repost", "title": "If I pour two liquids of the same density together without stirring, will they eventually mix by themselves?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dt5rttj"], "text": ["Whether or not liquids mix does not depend on their density, but their chemical properties. Typically, that means whether they are hydrophilic (attracted to water) or hydrophobic (fear water). For example, water is hydrophilic, oil is hydrophobic, so they don't mix at all. Alcohol is somewhere inbetween, so you can mix it with water, but it can also be mixed into gasoline. Not all liquids fall into either of these categories though. Liquid mercury for example won't mix with either oil or water, but readily mix with other liquid (or solid) metals. This is for example how you can extract gold from sand with mercury: The gold will solve in the mercury, leaving the sand behind. The gold can then be removed from the mercury through chemical processes."], "text_urls": [[]], "score": [10]}}, {"q_id": "7smju6", "category": "Repost", "title": "How does metabolism work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dt5v6i7"], "text": ["This is a bit of a broad question but ill try my best to answer: Metabolism is actually an umbrella term to include *catabolism* and *anabolism*. Catabolism refers to the breaking down of biomolecules. For example, your digestive system breaking down a piece of steak down to individual aminoacids is catabolism. Catabolic reactions release energy in the process. Conversely, anabolism refers to the building of biomolecules. For example, using aminoacids to build body tissues. Anabolic processes require energy to happen. All these catabolic and anabolic reactions are known as metabolism. When people talk about slow and fast metabolism it has more to do with the efficiency of these reactions. Someone with a slow metabolism isn't as effective at building and/or breaking down molecules."], "text_urls": [[]], "score": [3]}}, {"q_id": "7sqjm1", "category": "Repost", "title": "Why does steam come out of water that's hasn't reached the evaporation point yet?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dt6qm0t"], "text": ["It has reached it's evaporation point. Water evaporates at any temperature above absolute zero - even frozen solid as ice through a process called sublimation. It hasn't reached it's *boiling* point, which is different from it's evaporation point. Water still evaporates below boiling."], "text_urls": [[]], "score": [4]}}, {"q_id": "7ss7jz", "category": "Repost", "title": "Reddit, I'm passing from the realm of tipsy to drunk. What is happening inside my body and brain right now?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dt77o84", "dt77ou5", "dt77par"], "text": ["\"Come with meeeee, and you'll beeeee, in a wooooorrrrlllldd of pure inebriation.\" ~ your brain, right now!", "Well shit...this post was an hour ago. OP should be completely wasted or passed out by now. Somebody go see if its time for hilarious selfies. Alcohol disrupts your nerve to nerve communication. Leading to slow responses, lack of ability to form good thoughts (aka reason), and general hilarity for all around.", "Alcohol is metabolized in the liver by two primary enzymes - alcohol dehydrogenase and aldehyde dehydrogenase. This is done so that ethanol can be made water-soluble and removed from the body (urine). Alcohol dehydrogenase metabolizes alcohol to acetaldehyde (toxic), and then further metabolized to acetate, and even further to Carbon Dioxide & water. Acetaldehyde is also called ethanal, and is responsible for flushing of skin and hangovers (typically why it also takes a while for a hangover to set in). It is also a carcinogen. That's a bit of the chemical nature of what it does. Also, fun fact, methanol is metabolized into formaldehyde."], "text_urls": [[], [], []], "score": [7, 4, 4]}}, {"q_id": "7szfr9", "category": "Repost", "title": "How do massive college campuses (especially ones in major cities) provide wifi accross such a large area", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dt8nxhe", "dt92nct"], "text": ["This is part of what I do and the short answer is a lot of access points. The slightly longer answer is that we use special wireless access points that are meant for high density campus use. These access points have several differences to the one you probably have at home. They are only access points, for starters, and not routers. They are centrally managed, meaning that at our Network Operations Center, our technicians are able to see and monitor in real-time the status and performance of every access point at every location on every campus in our state-wide system. All the settings of the access points (channels, transmitter strength, etc.) can be remotely changed. There\u2019s even software that dynamically monitors and adjusts those settings to try to optimize the performance. It\u2019s very complicated, as you can imagine, and very expensive, especially once you factor in the training and salaries of the on-site technicians and the initial set up, which usually includes outside specialist engineers. And that\u2019s why your tuition is so high.", "The antennas used in enterprise-scale wifi are sometimes a bit unusual. Indoors in large buildings they sometimes use a distributed antenna; essentially a long coax cable with slits cut into it\u2019s shielding so that it leaks RF along it\u2019s entire length. DISCLAIMER: I am not a network engineer, and this info is second hand from a friend who is an RF engineer for a major wireless carrier who designs large wifi installations professionally."], "text_urls": [[], []], "score": [40, 3]}}, {"q_id": "7t37a7", "category": "Repost", "title": "What is an MD5 Hash?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dt9ibj4", "dt9igf5"], "text": ["MD5 is a cryptographic hashing algorithm. By feeding it data, it spits out a certain number, called a hash. Any time the same data is run through the algorithm on any computer, you get this same number. A hash is a set size designated by the algorithm, for example MD5 makes 128 bit hashes, meaning this number must be between 1 and 2^128. As a hashing algorithm, it has the property of being cryptographic, meaning that it is not feasible (in theory) to produce some data that makes a certain hash. You can think of it as a fingerprint, and that is generally how it is used. For example, if I were to want to make sure you got the right file from me, I could hash my copy, send you the hash, and have you hash the file as well. If the hashes match, we have the same file. No hacker can make a file that has the same hash as mine, there is just no good way to do it. MD5 however is a broken hash function and should not be used. Something like SHA256 or the newer SHA3 functions are more secure. MD5 is broken since people have managed to find a way to make two different files have the same hash.", "So let's pretend you want to make an account with Amazon. You give them a username and password. They store your username in a table but not your password (that would be an obvious breach of privacy). So instead they store a hash. Hashing is somewhat like scrambling an egg. It messes it up so bad that it doesn't look the same anymore. Also it can't be undone. Hashing uses incredibly complex math that I won't go into. For now I'll just use the term 'hash machine.' You can run a string of text through the hash machine and get an unrecognizable string of characters out the other side. There's one thing special about the hash machine. A line of text always has the same hash! So if you put your password into the hash machine, it'll spit out the same character string each time. That way, when you enter your password into Amazon, they can throw it through the hash machine and compare it with the string they have in their table. If it matches, it came from your password. The really fancy part is that, since it can't be undone, there's no way Amazon can see your password. All they can see is a bunch gobilygook that somehow corresponds to your password. An md5 hash is just a certain kind of hash with 128 bits. Recently it's been found to have multiple vulnerabilities, so the internet has generally moved on to SHA-256. But that's probably more than you needed to know"], "text_urls": [[], []], "score": [3, 3]}}, {"q_id": "7t3zsk", "category": "Repost", "title": "Why does our stomach make such awkward/weird noises when we\u2019re \u2018hungry\u2019?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dt9nyj8"], "text": ["Your intestines are full of less stuff. Basically, when you've got a lot of food in you, there's a thick mush in your intestinal tract that is getting churned and squished by a movement called peristalsis, and this mush muffles noise. When you don't have a lot of food in you, there's less mush. Instead, there's air and liquid. When your intestines produce the same movement, they're sloshing around air and liquid, and what you hear is the gurgling result."], "text_urls": [[]], "score": [9]}}, {"q_id": "7t411u", "category": "Repost", "title": "Why does a gentle push cause a door to slam when a window in the room is open?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dt9vihb"], "text": ["Even if there is no flowing air, there is less air resistance since you have removed the vacuum effect that happens when closing the door without an open window."], "text_urls": [[]], "score": [11]}}, {"q_id": "7t5v1c", "category": "Repost", "title": "How do rockets move through space if there's nothing to push against?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dta29s7"], "text": ["They move by pushing rocket fuel out. Essentially the fuel is what the rocket is pushing \"against\" in order to move. If you were in space, you could propel yourself in one direction by throwing a rock in the opposite direction. It's the same idea."], "text_urls": [[]], "score": [3]}}, {"q_id": "7t5vhs", "category": "Repost", "title": "why do our teeth chatter when its cold", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dta359w", "dta37vc"], "text": ["Your jaw shivers. Shivering is a response to cold - the rapid movement of the muscles generates warmth expending energy.", "Shivering is a mechanism used by the body to generate heat. It can increase heat production by up to 500%, but can't be sustained for long."], "text_urls": [[], []], "score": [3, 3]}}, {"q_id": "7t60n8", "category": "Repost", "title": "What are Neutrinos?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dta4q4h", "dtald2l", "dtanto8"], "text": ["Neutrinos are nearly-massless particles, which only interact with gravity and the weak nuclear force. They don't react to electromagnetism, and they have such a small mass that they usually don't interact with \"normal\" matter, and just pass right by. They're all around you, right now, passing effortlessly through your body. They're fundamental particles, so they aren't made of anything smaller (by our current understanding), so \"what\" they are isn't possible to explain other than telling you how they behave. They just *are*.", "Neutrinos, they are very small. They have no charge and have no mass And do not interact at all. The earth is just a silly ball To them, through which they simply pass, Like dustmaids down a drafty hall Or photons through a sheet of glass. They snub the most exquisite gas, Ignore the most substantial wall, Cold-shoulder steel and sounding brass, Insult the stallion in his stall, And, scorning barriers of class, Infiltrate you and me! Like tall And painless guillotines, they fall Down through our heads into the grass. At night, they enter at Nepal And pierce the lover and his lass From underneath the bed \u2013 you call It wonderful; I call it crass. -- John Updike It's not entirely accurate, since they do have a small mass (which wasn't known when Updike wrote the poem), they do have weak-force charge (and gravitational charge, and Higgs charge), and they do interact a bit.", "A write-up aimed at a middle school audience. Comments in parentheses (like this) are more suitable for high school or college students. --- A neutrino is what's left over when a neutron splits into a proton and an electron. This process is called \"beta decay.\" A neutrino has no electrical charge and only interacts with other particles via the weak nuclear force. (This can be seen by observing that before the beta decay we just had a neutron with zero charge, while afterwards the electron and a proton charges cancel out, so by conservation of charge, a neutrino must have zero charge so that net charge remains zero.) This means it almost always passes through normal matter like a ghost! Billions of neutrinos pass through your eyeball each second, but not one will interact with even one atom of your retina in your lifetime! A neutrino has almost no mass and for a long time was thought to be massless. We now believe it has a mass about one-millionth that of an electron, or in other words, one-billionth of a proton or neutron. (A neutrino, like protons, electrons, and neutrons, has a \"one-half spin.\" Such particles are called \"fermions\" and this means they always have a small amount of angular momentum and can't overlap.) Most neutrinos can be found zipping along at just under the speed of light. (When a neutron splits into a proton and an electron, there is some left over energy. Because of a combination of conservation of energy and conservation of momentum, each particular gets a fair share of that left over energy as kinetic energy. Because the neutrinos mass is very low, it has to go very fast to pick up its fair share of kinetic energy.) Most of the neutrinos passing through the Earth come from our own sun. But some are relic neutrinos left over from the big bang, or created in distant supernovas! Scientists theorized that neutrinos *must* exist decades before they were able to to detect them. When a beta decay event occurred, they could see the electron and proton shooting off in opposite directions. But this appeared to violate the conservation of energy! So they made up a third particle, neutrino. Later they would prove this was the right explanation. Today scientists are able to directly detect neutrinos, but only by using *giant* sensor arrays. They bury their neutrino detectors deep underground or under the south pole so they don't get confused by light or other particles. When scientists first built these detectors, they observed that they were counting less than half the number of expected number of neutrinos from the sun. Observing differences between experiments and theories is the first step in the scientific method. As they studied the problem, scientists learned that neutrinos come in three kinds, and that as they fly through space, they change from one kind to another, and that some kinds are easier to detect than others. The scientists realized that by the time the neutrinos from the sun reached Earth, some of them hard already changed into different types that were harder to detect. This is also how we first learned that neutrinos really do have mass! By working hard to make sure their theories agreed with observed data from experiments, scientists were able to understand neutrinos even better. That how the scientific method leads to an increase of understanding over time."], "text_urls": [[], [], []], "score": [207, 20, 8]}}, {"q_id": "7t7ems", "category": "Repost", "title": "How do firefighters/investigators find the exact cause of a fire and where it started after everything\u2019s burnt to ashes.", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dtafobb"], "text": ["fire science. When entering a burnt building/car/field etc...the investigator can deduce where the fire started how much of a certain area is burnt, by looking for ignition sites (ie, electrical outlets, gas pipes...). Once they locate the point of ignition they can either observe the cause or have to do some forensic test on the ash to test for residual byproducts of the accelerant (ie, fuel)."], "text_urls": [[]], "score": [3]}}, {"q_id": "7t7zob", "category": "Repost", "title": "how do fraternities work? Do they serve any real function to the university?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dtas91d", "dtalb6b", "dtas5qd", "dtalm0a", "dtat37l", "dtasr21"], "text": ["Benefits to University: - Provides a social network for students who join. - Provides social and extracurricular events for students without the need for university resources. - Provides opportunities for students to gain experience holding leadership positions. - Often provides housing, which can be limited on some campuses. - Depending on a university's relationship with fraternities and sororities, it can provide the university with ways to regulate social events that can't be applied as easily to non-Greek events. - Fraternities and sororities typically require some amount of philanthropy, which benefit the community and improve a school's reputation. - Provides for networking opportunities that can help students with their careers. - Increased donations from alumni. Harm to University: - \"Pledging\" a fraternity or sorority often involves hazing, which can mentally and physically distress students. There have even been instances of people dying due to hazing. - Fraternities and sororities generally throw parties with alcohol, which can lead to irresponsible behavior, injuries, crime, etc. This is bad for students and the university's reputation. - Associating mainly with one's own brothers or sisters may limit interactions with other students and/or decrease the diversity of people a student gets to know. - Students may feel pressured to spend unnecessary amounts of time and money on matters related to their chapter. - Dealing with fraternities and sororities requires time on the part of the university's staff, often requiring hiring people specifically for this purpose. - Promotion of \"fratty\" culture, which can include immature behavior, sexism, sexual misconduct, excessive alcohol consumption, etc.", "Interesting question. Fraternity is a short for Fraternal Organization. Literally a brotherhood. Like minded, funded, intrests etc In the case on campus many began over a century ago as literal acedemic and social clubs. Like any many a club they have standards for admission. Not everyone can join the varsity baseball team,. Marines or country club. They have dues, silly rituals, and housing. Members pay rent to live there. They act as small businesses running a rental property and paying for social activities. Yes parties. A frat at one point greased the social wheels allowing the members to meet women. Why were/are the women there? Boys I guess. Exclusivity at one time increased their desirability. Like now, people want what they can't have. At their best the provide a center for campus life, housing and academic support for their members. At their worst well we all hear about that What purpose now? Well they still provide the good and the bad but campus values have changed. Isms like elitism is considered bad. Exclusion is considered bad now in our postmodern collegiate reality. It works for their members and pisses off more for these reasons given. Is there a net benefit to the campus? Well if you are truly diverse you have those who believe exclusive is good and those that think bad. But that isn't what vox collegeum can accept now. It's not clear they ever were a plus or minus for colleges. Less know fact, up until the 70s most frats had a House Mother, an older woman that lived in the house. I sometimes wonder if many of the bad things we hear about frats would be mediated if that Mom returned", "Depending on the university, they can be the core of \"involved\" students. A commuter school, or small school, often has its student government, sports pep rallys/student sections, volunteering, homecoming parades, etc being done by the Greek system. These are sometimes the students that are heavily involved in the extra curricular activities. The dbag frat boy cliche stereotype does definitely have truth to it tho, not always, but often.", "This is one that will surely receive different answers depending on who you ask. Interestingly (at least to me), I was a British student who studied in the US for four years and joined a Fraternity in my first year at College, so I feel I have a good view on this subject. Primarily, a fraternity is a brotherhood of men who are bound by the guiding principles and standards that are associated with that particular fraternity. They vary from fraternity to fraternity but usually ground themselves in principles such as brotherhood, education, leadership, etc. On the face of it, it looks like a group of guys who like to drink and party together. Whilst this is essentially true (and surely that\u2019s a large part of college anyway), we used to put on several charitable events for a national charity and would volunteer in the local community as well. We were able to raise a lot of money for those in the community and would bring good pr to our chapter and university. I\u2019m not suggesting we were always saints but the boys were a family away from my family and we had a great time together and I made friends I hope to keep forever. It\u2019s not for everyone but made my time as college a great one!", "Plenty of universities function without them. They have benefits and drawbacks to those who get involved but they make ultimately make no necessary contribution. Their functions can be found otherwise.", "Social Fraternities (i.e. the Greek System) are social organizations that are supposed to bring together like-minded individuals and give a structured recreational environment to balance the generally individual focus of academic studies. The original goal was not to create drinking clubs, but instead provide a semi-organized environment where students could relax, develop social skills, and have a support environment to assist in a student's studies. They were designed to offer benefits to the school through community service, philanthropy, and competitive pride as frats tried to out-perform one another in academics and intramural athletics. Sadly, a significant number of people join them today because of the perceived party lifestyle. In that sense, they can be actually disruptive to the academic mission of the school. Note that there are academic fraternities to which you gain entrance through school performance or professional area of interest/study. While these may use the Greek letters for their names, they are not part of the \"Greek System\" at a college or university."], "text_urls": [[], [], [], [], [], []], "score": [368, 39, 24, 15, 4, 3]}}, {"q_id": "7t9y38", "category": "Repost", "title": "how do people deep fry ice cream? Wouldn't it melt?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dtb0k95", "dtb0b1v"], "text": ["It's not the ice cream that's fried. It's coated in batter, basically a thin layer of donut around the whole thing. The dough is fried and insulates the ice cream.", "First of all the ice cream for this is frozen at extremely cold temps, then it is quickly battered and fried, so while the ice cream softens up a little....it is still plenty cold."], "text_urls": [[], []], "score": [3, 3]}}, {"q_id": "7tcm8w", "category": "Repost", "title": "Why is your palm lighter than your skin?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dtbim5i", "dtbizm0"], "text": ["The palms and the soles don't have any melanocytes, the cells that produce the pigment responsible for the skin color. (melanin) More melanin = darker skin. edit: my english spelling sucks.", "They are lighter because they don't have as much melanin as the rest of your skin. Melanin helps protect your skin from the sun, and since our palms and the soles of our feet never get that much sun, there was no evolutionary pressure to get the melanin there."], "text_urls": [[], []], "score": [11, 8]}}, {"q_id": "7tgiis", "category": "Repost", "title": "All the bugs seem to disappear in winter but then repopulate in summer; where do they all go?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dtcatq1"], "text": ["Burrow into the ground, under tree bark, under the grass and leaves, leave behind eggs that hatch as it warms up. There are a number of wintering options for insects."], "text_urls": [[]], "score": [4]}}, {"q_id": "7th8lt", "category": "Repost", "title": "Why when you rub your eyes for long enough do you begin to see shapes, grids, and other stuff?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dtcrlwd", "dtckwa8", "dtctm9g", "dtcj9vy", "dtcuk6a", "dtcwpde", "dtd24lw", "dtctr38", "dtcrjmo", "dtdeyfg", "dtczrxh", "dtczjxk", "dtcvisk"], "text": ["The nerves in your eye are only programmed to do one thing, and that is to see light and color. When you mash down your eye, you force the fluid in your eye to push on that nerve. It senses a stimulus and goes \u201coh! I must sense light and color!\u201d So you process the pressure as sight instead of pressure Edit: I just learned this in human physiology the other day, and I wrote it right as I was about to go to sleep. I would imagine the pattern is due to the pattern of your rods and cones. Those are what actually detect the light and transmit it to the nerves. I\u2019m not sure if it will damage your eyes, but I\u2019ve always been taught that it\u2019s bad. I will go to my phys professor with some more of these questions tomorrow. Thanks everyone! Edit 2: What are the patterns caused by? Various photoreceptors being activated, the ones that don\u2019t activate haven\u2019t reached threshold so are dark spots. Can blind people see them? Depends on what kind of blindness they have. If it\u2019s retinal in nature, they can\u2019t. Why can I see them sometimes when I just close my eyes? Mind me but I forgot the full answer to this, I had a long day (phone became an expensive paperweight). I do know that the photoreceptors are being activated but not sure why. Is rubbing your eyes bad? Well it isn\u2019t good is pretty much all I can remember on this one. Sorry guys, hectic day!", "You have fluid in your eyeballs. The added pressure triggers your nerves in your retina to send signals through mechanical stimulation. The mashing can also give your nose an odd smell sensation due to added pressure.", "There's actually a name for it, called a phosphene. There was an artist that [drew what it looked like to him.]( URL_0 ) Anyways, you are directly stimulating your eyes through physical pressure, as opposed to subjecting your eyes to visible light.", "Something called the Law of Specific Nerve Energies; the sensory modality a stimulus affects is determined by the pathway, not the actual stimuli. Meaning, any stimulus to the rods and cones of the eyes such as pressure in the case of rubbing your eyes, will still produce visual sensations due to the tracts they take and the areas of the brain they wind up in. ( URL_0 )", "Because you are squeezing your eyes, you're exciting the cells in the back of your eyes. These cells normally can only be excited by light, so your brain thinks it can \"see\" the squeeze. ELI26: I used to do this **a** **lot** when I was a kid. I noticed that after a few moments, the image would solidify into something resembling a green tunnel. The walls were comprised of undulating spiral grids, each square being centered with a small circle. The end of this tunnel was about one half the width of my vision, and was static snow. After several moments, I began seeing detailed images of things in the snow. Vagu faces. Buildings... What I want to know is what exactly was my brain doing when this effect began generating such complex imagery?", "Could you damage anything related to your eyes by doing this?", "Your eyes are used to see light. Light is made from photons. Sometimes cells in your eye (and anywhere in your body) can produce very small amounts of photons themselves. Scientists think that you can make them produce even more of these photons by doing certain things like putting electricity into your head near your eyes or increasing pressure in your eyes by rubbing them. When your eyes are closed, you are able to see these very small number of photons because they are being made right inside your eye - your eye is extremely good at seeing photons! Fun game: close your eyes and look all the way to the left. Push against the lower-right corner of your right eye. You should see light in the top left of your eye. You can do the same by looking all the way right and pushing on the lower-left of your left eyes when closed. You see light in the wrong place because your eyes actually see upside down and your brain normally corrects this when your eyes are open.", "Sometimes when i close my eyes i see blobs of light. Sometimes theyre flashing and its darker to just open my eyes. Why does this happen? Is it just me?", "Everything that happens in your body that you can sense gets to you through some sort of biological wiring. If you put pressure on said wiring, it can trick your perception. For example, your arm may go numb if you lay on it a particular way. In the case of eyes, the pressure you apply sends the same signal through your nerves (wiring) that those particular shapes would send, so your brain tells you that that is what you must be seeing.", "These are entoptic phenomena, which are visual perceptions that originate from WITHIN the eye. The specific ones the OP is writing about are called phosphenes, which are lights/grids/colors that can arise after mechanical stimulation of the eye. Any mechanical stimulation of the eye can potentially stimulate the retina, which causes firing of the retinal ganglion cells and the perception of lights/flashes. This is why you can see flashing lights when you get hit hard in the eye or when you get a retinal detachment. This is also why babies who are born blind often rub their eyes vigorously--the rubbing provides them with visual stimulation. Other types of entoptic phenomena exist. Have you ever noticed that you can see your blood vessels when your eye doctor shines a bright light in your eye? Not an illusion--you're actually seeing the light on your peripheral retina casting a shadow over your retinal blood vessels. These are called Purkinje trees. In the right setting, some people can even see their own white blood cells moving through their vessels (blue field entoptic phenomenon). Source: I\u2019m an ophthalmologist", "All the explanations I'm seeing here are for the physical part, answering why rubbing lets us see *anything* if our eyes are closed. I'm quite interested in the next step: why are these signals interpreted (?) as patterns and structures in so many cases, rather than random bursts of light?", "So lots of people are covering why you see *something*, but not why it\u2019s specifically these shapes/grids/etc. So basically, you process visual input at a lot of different levels to build up a better idea of what you\u2019re seeing; you have to go from a bunch of individual cells which can only relay information about light by sending only one type of signal (on/off basically) at varying rates, and build up to what we actually consider vision. This processing begins in the eyes themselves, with horizontal, bipolar, amacrine, and ganglion cells in the retina. They have a lot of different functions, but the relevant ones here are things like basic edge and orientation detection. This could explain why you see these sorts of patterns, because your occipital lobe (associated with vision) is not getting a sensible type of input from the nerves in the eyes, so it doesn\u2019t really \u201cknow\u201d what to do with it and leaves it fairly raw. I\u2019m not 100% sure on this explanation at all, as I haven\u2019t actually read anything addressing your question specifically, but this is an educated guess about the reason for part of it. If you\u2019re interested in learning more, look into retinal processing, and you can build up from there.", "When you see something, it's because cells in your eye have been hit by light and sent electrical signals to your brain in response. Since this system is a biomechanical one, it's possible to trigger the same kinds of signals using other things than actual light. For example, rubbing or pressing at your eye can cause some of your visual cells to fire. Your brain can't tell the difference between signals that result from those cells being squished around and signals caused by actual light, so it just interprets them as some kind of visual input. These are called 'phosphenes' and they can also be caused by magnetic or electrical stimulation. This kind of thing isn't limited to your eyes, either - ever hit your funny bone? When that happens, you're putting pressure on a big nerve that goes through your elbow. This nerve usually brings information from your hand (specifically the pinky area and side of your palm) to your brain. When you smack it, that sends a burst of activity to your brain which is interpreted as tingly uncomfortable sensations coming from your hand - even though you hit your elbow and not your hand itself! With phosphenes, the 'phantom tingling' is experienced as phantom visual sensations, but the concept is the same. Your brain is always sitting in the dark of your skull, and all it can do is interpret the signals it receives as telling it something about the outside world - even if they're not."], "text_urls": [[], [], ["https://upload.wikimedia.org/wikipedia/commons/2/2a/Phosphene_artistic_depiction.gif"], ["https://en.wikipedia.org/wiki/Law_of_specific_nerve_energies"], [], [], [], [], [], [], [], [], []], "score": [9972, 1718, 614, 211, 36, 7, 7, 4, 4, 4, 3, 3, 3]}}, {"q_id": "7thisp", "category": "Repost", "title": "What's the difference between LTE and 4G?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dtcly4q", "dtcnwae"], "text": ["4G is branding, LTE is the name of the wireless standard the branding is based on. ATT also called their hspa+ 4G in order to compete with Verizon and Sprint who actually had 4G. I had an iPhone 4S when ATT changed my service from 3G to 4G by changing the wording on the display, not actually changing my speeds :(", "When your phone displays 4G it means it's using an HSPA+ connection. HSPA+ doesn't meet the 4G standards (it's an upgraded 3G standard) but LTE does. Some American carriers decided to market hspa+ as 4G in order to compete with other networks who had true 4G (LTE)."], "text_urls": [[], []], "score": [59, 15]}}, {"q_id": "7tj1og", "category": "Repost", "title": "Why does drain cleaner work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dtcvepn", "dtczyyc"], "text": ["Drain cleaner is mainly lye, AKA caustic soda, AKA sodium hydroxide. Lye destroys organic compounds. Most of the things clogging a drain (hair, food bits, poop, snots) are destroyed by lye. Lye can also make short work (relatively) of a body, which is why it has been used in crimes to dissolve people. Don't spill drain cleaner on you, it will eat you.", "Drain cleaners are chemicals which can cause \"hydrolysis\" of certain chemical bonds. There are two main types of chemical drain cleaner: Concentrated acid (e.g. sulfuric) and Alkali (e.g. sodium hydroxide) Although, these sound like opposites, the chemical reactions which occur have a very similar overall effect. Complex insoluble molecules are cut up into shorter, soluble ones. Hair, and food residues contain protein, which makes them solid and insoluble. Proteins, however, consist of individual chemical building blocks called amino acids. The bonds between the individual amino acids in the protein can be hydrolysed by the acid, causing the protein to break into the individual amino acids which are soluble. Effectively, any solid protein just dissolves into soluble chemicals. A similar reaction occurs with fats. Complex fat molecules are broken down into soluble \"fatty acids\" and glycerol"], "text_urls": [[], []], "score": [8, 3]}}, {"q_id": "7tjttb", "category": "Repost", "title": "How come our eyes rotate smoothly while following an object, but jitter when we scan side to side?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dtd14br"], "text": ["Previously answered [once]( URL_0 ), [twice]( URL_1 ), [three times a lady]( URL_2 )."], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/50spo8/eli5_why_can_our_eyes_only_move_in_a_smooth/", "https://www.reddit.com/r/explainlikeimfive/comments/3hn07y/eli5_why_cant_we_move_our_eyes_in_one_smooth/?utm_term=e51e6fc8-5519-4328-bf92-5eb3ab0bd700&amp;utm_medium=search&amp;utm_source=reddit&amp;utm_name=explainlikeimfive&amp;utm_content=16", "https://www.reddit.com/r/explainlikeimfive/comments/42au32/eli5_how_come_our_eyes_can_scroll_when_focusing/"]], "score": [3]}}, {"q_id": "7tjvhw", "category": "Repost", "title": "Why do water resistent devices have a resistence time limit? How does the water eventually get in?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dtd71yu", "dtd5to8", "dtdd2mm"], "text": ["there are microscopic forces that will drag water into places you wouldn't otherwise expect it. capillary action and osmosis are 2 you can google easily enough. it's impractical to shield a device from these things when it's not intended for under water use, so the time limit reflect how long it takes for those forces to overcome the macroscopic barriers.", "Anything which isn\u2019t naturally water resistant has to achieve that seal in some way: usually it is either chemical (a coating) or mechanical (a seal like an O-ring). However, given enough time or wear, seals can crack or chemicals can wear off. Especially in the case of mechanical seals this is why depth is important: the pressurization and then depressurization stretches the seals causing cracks to form.", "Because that is the duration of the test. Each standard you want your product to meet needs testing and certification and each test program costs money. For instance IP7 standard requires 1m depth for 30 minutes with no harmfull effects (not necessarily that no water gets in). It may very well be that it water will never get in at that depth, but you haven't got proof of compliance. If you think that a higher standard will make your device more attractive to buyers you'll have to have it undergo a more stringent test."], "text_urls": [[], [], []], "score": [7, 6, 3]}}, {"q_id": "7tkajo", "category": "Repost", "title": "what is smell? how come it lingers for a bit and then goes away?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dtd3yzi"], "text": ["A smell or odor is the volatilized chemical compounds of a substance that are floating in the air. So in short, it's molecules or atoms of a substance (e.g., *bacon*) that have been released into the air through some sort of chemical reaction (e.g., *frying*). As those molecules encounter receptors in an animal's olfactory organ (e.g., *nose*), it is perceived by the central nervous system organ (e.g., *brain*) as a smell or odor (e.g., *stank*)^1 or whatever. TL;DR: a smell is too-small-too-see little bits of things flying through the air and smashing into your nostrils. ^1 Bacon stank smells *goooood*, though."], "text_urls": [[]], "score": [4]}}, {"q_id": "7tkqzd", "category": "Repost", "title": "Why do the eyes move rapidly during REM sleep?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dtd9nfo"], "text": ["To be honest, we don\u2019t really know. In the 1950s it was thought to be linked with the sleeper\u2019s dreams, but the studies have been unconclusive. Peretz Lavie, who is kind of a specialist of sleep, thinks that these rapid eye movements are correlated to our brain forming memories during REM sleep, but we still can\u2019t figure out why. Fun fact : it seems that our pattern of eye movement during REM sleep is linked to our mother tongue : Europeans, Africans and Americans have a horizontal REM, whereas Asians have a vertical REM."], "text_urls": [[]], "score": [8]}}, {"q_id": "7tkr9w", "category": "Repost", "title": "What happens to all those error reports Windows sends when a program crashes? There has to be a countless amount of them.", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dtd7aef"], "text": ["Microsoft performs automated analysis of them to group them together by type. As you say, there are millions of them, so the first step is to reduce that number. If the same bug causes a hundred thousand crashes then the developers only really need to see the information about that crash once. So this analysis determines that \"these crashes are all really caused by the same bug\", and bunches them together. Then this information is made available to the developers of the application, so they can log in on a website and get information about reported crashes. They'll then log in to the website where this information is available, and see that \"this crash occurred 100,000 times within the last month, and have the option to download information about the crash. This data contains information about what the application was doing at the time of the crash, as well as a description of the system it occurred on. The developers can use that to figure out what happened, and fix the bug."], "text_urls": [[]], "score": [4]}}, {"q_id": "7tm558", "category": "Repost", "title": "How does laser eye treatment correct blurred vision?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dtdi7kn"], "text": ["It burns off tissue until you are left with the correct cornea thickness to let you see better."], "text_urls": [[]], "score": [9]}}, {"q_id": "7tmfp9", "category": "Repost", "title": "How were bridges connected from high altitudes way back before modern technology?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dtdk73n", "dtdlddh", "dtdlfgc"], "text": ["The most \"old school\" method I know of involves staring with a single line of rope or cord. If the gap is across water, one end can be brought across with a boat or swimmer. If that's not an option a device such as a grappling hook can be used to secure one end over a small enough distance. Once you have a single line across you can double the strength by sending somebody across the first line with a second rope and you are well on you're way to constructing a simple rope bridge or the framework for a more sturdy bridge structure. Please somebody more knowledgeable tell me a better way.", "Easiest way is to throw a thin rope or line over the gap. If you can't make it with a line attached to a stone, then use a bow arrow. Once the thin line is over. Use it to pull over a thicker line. Then a rope. Then a thicker rope.", "What do you mean \"high altitudes\". Older bridges were frequently just some ropes thrown over whatever you're crossing, or some planks thrown across. If it was too big for that you took a boat or went a different way. [The wiki article on London Bridge]( URL_0 ) lists out the previous older ones. But in short, it was cross somewhere shallow or take a boat, until the romans built a floating bridge (basically a bunch of boats tied up together). As technology improved they eventually were able to make stone bridges."], "text_urls": [[], [], ["https://en.wikipedia.org/wiki/London_Bridge"]], "score": [7, 3, 3]}}, {"q_id": "7tntqs", "category": "Repost", "title": "How do movies, TV Series etc get to torrents? Who actually pirates them, upload and how?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dtdysbl"], "text": ["People who think others should be able to see them without paying \"rip\" them, generally either from streaming sites or from DVD/bluray releases (though there are other options, like using a TV-capture card on a live broadcast). Generally they'll transcode them into more manageable formats next, and then they use their own torrent client (usually) to generate a .torrent file from the files they have . This file is very small, so they upload that to one or other of the torrent-indexing sites (or just hand it out to friends) and run their torrent client until there are enough other copies out there that the torrent has become self-sustaining. Sometimes people who do this band together into whole communities, and sometimes they just do it for one thing that they want to make available. That's all."], "text_urls": [[]], "score": [4]}}, {"q_id": "7tp8d5", "category": "Repost", "title": "Why has only about 5% of the ocean been discovered? What makes it so difficult and how has technology not been developed to uncover more?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dte740d"], "text": ["The pressure will squish all but the most sturdy vehicles. These super-sturdy vehicles move very slowly, so the very small number of them have been sent to the most \"interesting\" places. The rest, alas, isn't interesting (or profitable) enough, so far."], "text_urls": [[]], "score": [5]}}, {"q_id": "7tqsf9", "category": "Repost", "title": "What is ADD and ADHD and what is the difference between the two?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dtej8wa"], "text": ["ADHD stands for Attention Deficit Hyperactivity Disorder. There are now two types of diagnoses: type 1 (inattention without hyperactivity) and type 2 (hyperactivity/impulsivity). Some doctors also consider a combination of the two to be a third type. When someone refers to ADD they are using the old term for type 1 ADHD."], "text_urls": [[]], "score": [4]}}, {"q_id": "7tro3y", "category": "Repost", "title": "What is game theory in economics?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dteoolw"], "text": ["Game theory is a branch of mathematics built around assigning value to particular outcomes, and then using these values to predict what individuals within a system will do. The most basic concept in game theory is called the [Prisoner's Dillema]( URL_0 ). It hekps explain why individuals will sometimes make non-optimal choices. For example, consider the process of large companies laying off large amounts of workers. While the net losses for the system are vast, the company itself, (or rather the few individuals at the top) come out ahead, and thus that's the decision they take."], "text_urls": [["https://en.wikipedia.org/wiki/Prisoner%27s_dilemma"]], "score": [3]}}, {"q_id": "7ttalw", "category": "Repost", "title": "What happens in our body that makes our bones make a popping sound when we \u201ccrack\u201d our knuckles, back, neck etc..?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dteznhn"], "text": ["It's actually not the bone you are cracking when hearing this. Your joints are two ends of a bone ensealed(is this a real word?) with a synovial membrane. Inside this membrane is synovial fluid to keep the joint moving nice and smooth. When you crack your knuckles you actually form a vacuum space in this fluid which then pops. This popping creates the sound you hear."], "text_urls": [[]], "score": [10]}}, {"q_id": "7tttzi", "category": "Repost", "title": "How can we tell the difference between what the actual temperature is and what the \"Feels Like\" temperature is?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dtf3vjy"], "text": ["Feels like is determined by humidity and wind. Simply blocking those factors will yield the appropriate result."], "text_urls": [[]], "score": [3]}}, {"q_id": "7ttyz5", "category": "Repost", "title": "Why can't you put metal in the microwave?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dtf7ugb"], "text": ["You can, but it's going to kill your microwave. The flat metal case around the microwave will ground the microwave energy away from the magnatron . A sharp object like a fork in a bowl is going to collect that excess energy till the electric potential sparks to a wall. These energy burst also cause feedback in the magnatron and harm it."], "text_urls": [[]], "score": [4]}}, {"q_id": "7tuobd", "category": "Repost", "title": "Why do metal objects like spoons make microwaves explode?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dtfbjup"], "text": ["As someone who's stuck a spoon in a microwave, they don't exactly \"explode\". I mean... I lived to tell the tale. Metal reflects microwaves rather than absorbing them like food. If the metal is flat, it just acts a lot like the walls of the microwave itself, and is generally harmless. Those metal linings on Hot Pocket and microwave pizza \"trays\" are meant to do just this, to better cook the food. Pointy (foil) or weird-shaped objects (spoons n' stuff) cause the microwaves to reflect in strange ways. It may focus the microwaves into a small area by reflection, it may generate an arc because the microwaves cause a current to run along the metal, etc. This can set your food on fire, or ruin the microwave. Still won't explode, though."], "text_urls": [[]], "score": [7]}}, {"q_id": "7turt3", "category": "Repost", "title": "Why can programs like Discord and Skype have little to no delay, but news broadcasts have a huge of delay for the field reporter portions?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dtfbzqs"], "text": ["News broadcasts are using satellite internet, which has higher latency than your typical DSL or fiber internet."], "text_urls": [[]], "score": [5]}}, {"q_id": "7tv7eq", "category": "Repost", "title": "What happens to a living human body in a vacuum, assuming it has an ample air supply? (breathing from a tank or tube for example)", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dtfg6l2"], "text": ["If you've got an air supply, your lungs will burst from the pressure of the air inside. You'd actually probably live a little longer if you didn't have an air supply. Step 1: exhale. The low pressure causes water to vaporize, so you'll feel \"boiling\" of the moisture in your mouth, and your skin will swell up (but probably not burst). You'll be getting unadulterated cosmic rays, so that's bad. And if you're in sunlight, expect a terrible sunburn. Soon after you'll get the bends from the sudden decompression. But you won't freeze instantly because without air around you, your body can't radiate heat quickly enough to do so, despite being \"cold\" in space. Somewhere in all of this, you'll die."], "text_urls": [[]], "score": [3]}}, {"q_id": "7tx7an", "category": "Repost", "title": "How do TV shows and movie series keep the same feel and style while having multiple directors over the course of their run?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dtfwjqv"], "text": ["Shows that use multiple directors (which are most) have positions such as producer and showrunner whose jobs entail keeping the themes and feel of the show consistent."], "text_urls": [[]], "score": [3]}}, {"q_id": "7tzrmv", "category": "Repost", "title": "Why does light ONLY travel at 300,000km/s and not faster? Why this speed limit?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dtggmi8"], "text": ["The full answer is: Nobody knows. The speed of light is a constant value that seems to be an inherent universal value. In many respects it is like the gravitational constant G or pi. It is what it is, and that's just how it be. There are more speculative ideas however (E.G. String \"theory) that propose origins for the various constants and laws of physics, but they are nothing close to being proven or provable, but there's no known reason for it to be at the precise speed it is."], "text_urls": [[]], "score": [3]}}, {"q_id": "7u046q", "category": "Repost", "title": "Why is it so disorienting using an escalator that isn't working?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dtgihpb", "dtgk1n9"], "text": ["I don't think \"disorienting\" is the correct word here. Anyway, escalators have taller steps then ordinary stairs, making it a lot more inconvenient to climb them, since you're used to smaller steps.", "I have often wondered this myself and this is my own reasoning: We are taught how to use escalators. It's a learned skill that you get conditioned into, that you have to brace your movements differently when stepping on an escalator. It's got the metal floor and looks different to normal stairs so you get accustomed to adjusting your body when you use it. Instead of pushing down on your feet to step up the stairs, you remind yourself to stay still after stepping on & brace for movement. When it breaks, you already have that muscle conditioning in built. It works automatically, so you respond automatically how you're taught. Your body knows that escalators look different from stairs, not just because they're moving but also cause they have the moving handrail and metal flooring. Your brain takes a moment to override the automatic part of your brain and act differently than conditioned. There's a small conflict in your brain determining whether to treat what's in front of you as an escalator, which your brain thinks *always moves*, or as stairs. It's got to relearn what it already thought it had learned."], "text_urls": [[], []], "score": [7, 4]}}, {"q_id": "7u05ms", "category": "Repost", "title": "How the morning after pill work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dtgl8rl"], "text": ["The most common \"morning after pill\" is levonorgestrel, a progestin-only form of birth control. It prevents pregnancy by inhibiting ovulation and thickening the cervical mucous. Thicker cervical mucous means fewer sperm can enter the uterus and travel to an egg in the reproductive tract. Ovulation is when the egg leaves the ovary and enters the fallopian tube. If ovulation is prevented, there is no egg in the uterus or fallopian tube to be fertilized, and no pregnancy. Another type of \"morning after pill\" is ulipristal acetate. This has also been shown to inhibit ovulation, but evidence suggests that it also delays maturation of the endometrium (lining of the uterus) making implantation of a fertilized egg less likely, although the science isn't settled on this front."], "text_urls": [[]], "score": [5]}}, {"q_id": "7u2zas", "category": "Repost", "title": "What is Shortselling? (Shorting a stock) How does it works?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dth4lyw", "dthlruy", "dth6i3f", "dth4rod"], "text": ["Basically, you borrow the stock from your broker. So let\u2019s say you short 1 share of stock XXX that\u2019s trading at $100. What you have done is sold 1 share that your BROKER owns for $100. You receive $100 but now owe 1 share of XXX to your broker. Sometime in the future, when you close out your trade, you have to give 1 share of XXX to your broker, whether that\u2019s from the shares you already own or having to buy a share of XXX and give it to the broker. So, if in the future, XXX is trading at more than you shorted for, say $110, you have to buy the stock the stock at $110 to reconcile the short and therefor lose $10 due to the trade. Vice versa in the case of the stock price falling during the time you hold the short", "A really good example (that most people don't understand) is what happened in the movie \"**Trading Places**\" with Dan Aykroyd and Eddie Murphy. If you recall, Aykroyd and Murphy go to the trading pit for Orange Juice. Once trading begins, the buyer for the Duke Brothers starts buying everything. The Crop Report is to be released shortly, but other buyers believe the Dukes have inside info and \"want to get in on it\" (2 traders actually say this in the film). This forces the price up, as buyers are willing to pay the higher prices, thinking the price will continue to rise. When the price hits $135 or so, Aykroyd shouts that he's selling. The key thing to note here is this: **he has no shares to sell at this point**. Buyers pay Aykroyd's asking price, but some folks begin to have doubts and the \"Buy\" price begins to drop. Buyers decide to wait for the Crop Report before buying more. When the Crop Report is aired, and reveals everything is fine with the OJ market, buyers suddenly realize they've paid *way* too much, and start selling to minimize their losses. After all, one way to \"Maximize profit\" is to also \"Minimize loss\". This sell-off drives the price down very quickly. Now, with the price around $25 a share, Aykroyd begins to buy. He **must** buy at some point; the options he buys *later* will be used to fulfill the \"sell\" trades he made *earlier*. If he didn't deliver the agreed-upon number of shares on those \"sell\" orders, the deal would be void. Everyone knows the saying, \"*Buy low and sell high!*\", but \"short-selling\" is like saying, \"Sell high and buy low!\". You want to sell high and have the price *drop*, but if you sell \"high\" and the price *increases*, you're hosed. You have no choice but to pay the higher price because **you're obligated to deliver the number of shares you already sold**. So, \"short-selling\" is *selling stuff you don't yet own*. You'll have to buy at some point, and your hope is to buy at a price lower than you sold.", "When you short 10 shares of XYZ, you are essentially buying -10 shares. Instead of paying, you get money, when you sell them, you have to pay money back. If XYZ goes down, you pay less back than you got, and make money. Under the hood, you are borrowing 10 shares of XYZ from your broker and immediately selling them. If XYZ is trading at 50, you get $500. If XYZ goes down to 40, you can buy 10 shares for $400, give them back to your broker, and pocket the difference. Why not just keep the money? You have to pay your broker interest on the value of the stock while it is shorted, and they can demand it back at any time. That means that if the stock goes up to 100, the broker can make a margin call (demanding you to pay outstanding debts). You would have to pay $1000 to buy 10 shares, losing $500 on your investment.", "you borrow stock from another investor at your brokerage firm, and sell it. you \"owe\" them that stock back at some point in the future. In reality, the brokerage does the math, much like lending cash at a bank, the guy with a checking account does not know that his paycheck is being loaned out to others, and so long as everyone doesnt run to the bank to withdraw their whole balance, (at which point the bank would throw up their hands and say \"sorry guys, we lent a lot of that money back out, we cant cover all of these withdrawals) the world is none the wiser. similarly with stock, there is a thing called a short squeeze, where if all of the long shareholders suddenly want to sell their stock, the short holders will have to close their positions and replace the stock they borrowed. the brokerages set thresholds as far as short coverage, typically they will only short up to 70% of the shares in their control. but more volatile stocks may have lower limits (or no shorting at all)"], "text_urls": [[], [], [], []], "score": [13, 4, 3, 3]}}, {"q_id": "7u3fs7", "category": "Repost", "title": "Why does the throat \"freeze\" when you chew/eat a peppermint gum/candy?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dth8egt"], "text": ["Your nerve receptors (in your mouth) interpret a compound in pepermint as \"cold\" in a way it is tricking your body. If you had pepermint extract or oil and put it anywhere on your body you would still have the same effect but however to a more mild degree in some places due to there being less nerve receptors."], "text_urls": [[]], "score": [4]}}, {"q_id": "7u4aek", "category": "Repost", "title": "how do solar panels capture energy from the sun?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dthgnwg", "dthglxd"], "text": ["Photons have energy in them. When those photons hit a special semiconducting material, they can transfer that energy to the electrons in the semiconductor. This allows the electrons to move to a nearby metal electrode and loop around through a circuit to a baseline electrode on the other side of the semiconductor.", "An LED works by having two different materials butted up against each other. When current flows it pushes an electron across the junction of the two materials it can get rid of some energy so it gives off a photon A solar cell absorbs a photon which gives an electron a big enough kick to cross the junction so current flows."], "text_urls": [[], []], "score": [5, 3]}}, {"q_id": "7u8y9s", "category": "Repost", "title": "Why do news stations have unbearable video feed lag between two people while for me talking to someone on facetime or skype has virtually no lag.", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dtih5kr"], "text": ["Satellite connection. Sometimes they don't have the luxury of a high speed internet connection on the field. Even that may not be enough do deliver the high quality video feed they require. So they have to use a satellite connection, which means the signal, regardless of bandwidth, needs to cover a lot of distance. In this case, not even the speed of light is fast enough. URL_0 According to this, just bouncing light up and down via a satellite takes 1/4 second, which is not much, but noticeable. Depending on the distance, one satellite is not enough, if the reporter is on the other side of the planet it will take a lot longer than that because the signal is relayed between multiple satellites. edit: added a source"], "text_urls": [["https://en.wikipedia.org/wiki/Satellite_delay"]], "score": [8]}}, {"q_id": "7u8zfn", "category": "Repost", "title": "Why is Prince Philip called Prince Philip but not King Philip if he\u2019s married to Queen Elizabeth II?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dtih6vn", "dtih3m7", "dtii0al"], "text": ["King is considered a higher rank than Queen. The Queen is the monarch of the UK, so her husband can't be a higher rank than her. The wife of a king can be a queen, but they would be a \"queen consort\", rather than a \"queen regnant\". A queen regnant being a woman who is the monarch in her own right. A husband of a queen regnant is called a \"prince consort\". So why not \"king consort\"? It comes back to that rank thing. Because for centuries having a king on the throne was the norm and having a queen regnant was unusual (until recently the laws were set up to give male heirs precedence), king was considered higher than queen.", "If i recall correctly, you have to inherit the role of King and it can\u2019t just be given, whereas if the King were to marry he could name his wife Queen", "A King is a higher rank than a Queen. Since Queen Elizabeth II is the sitting monarch it is not possible for her spouse to be a King. Instead he is a Prince Consort. Prince Philip also technically had claim as a prince of both Denmark and Greece but he gave up those titles when he married (or got engaged I cannot remember). There are different kinds of Queens, all being lower rank than a King but each being a different rank with each other. Queen Regnant: When a Queen is the Monarch sitting on the throne. They are the one in control of the monarchy. This is what Queen Elizabeth II is. Queen Regent: The mother of a heir to the throne that is too young to rule on their own. They temporarily have control of the throne till the proper heir is of age. This is what Cersei from Game of Thrones was during Tommin's reign. Queen Consort: The wife of a sitting King. Queen Dowager: The widow of dead King who is not a sitting regent. They have no explicit power but often have influence in court."], "text_urls": [[], [], []], "score": [21, 3, 3]}}, {"q_id": "7ubzmg", "category": "Repost", "title": "What is a 'knot' in the context of massages and how does poking them relax you?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dtj4bfr"], "text": ["They are often called [Myofascial trigger points]( URL_0 ). They aren't fully understood but as I understand it, they are a small bundle of muscle fibers that are (or have been) contracting (and maybe holding) when they shouldn't be. Possibly due to issues with the associated nervous system....which is why they might be related to mental/emotional tension. They might be relieved by physical treatment (massage etc) as that can help to loosen and align the muscle fibers, maybe 'resetting' the nerve endings that are causing them problems."], "text_urls": [["https://en.wikipedia.org/wiki/Myofascial_trigger_point"]], "score": [4]}}, {"q_id": "7udbmp", "category": "Repost", "title": "Whats the water situation in Cape Town? Was this expected? Will this happen to other cities? Should other countries be worried?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dtjgnor", "dtjhxjb"], "text": ["They have been in a state of drought for years and the city population has not met the restriction goals to ration the water that they do have. As such they have been running out of water faster than they can build facilities to treat waste water or filter salt water. They have a number of plants in production to attempt to meet water needs, but they have encountered delays and will not be operational before they run out of water. Yes this was expected, but it was mostly ignored by the population till it was too late.", "Cape Town has been considered a very green city for awhile. They've worked very hard to be very responsible. One thing that led to their water shortage is due to their \"greenness\" there was a lack of urgency in moving forward to find supplemental water supplies. Now, kick in a severe drought AND a 30% population boom over the last decade or so and they are caught with their pants down. Now it's a very serious emergency. Their main water reservoir is at 13% of capacity and the clock is ticking."], "text_urls": [[], []], "score": [6, 4]}}, {"q_id": "7ueio4", "category": "Repost", "title": "How do viruses cause such a variety of symptoms (If they for the most part just destroy cells and multiply)?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dtjos4e"], "text": ["1) Most viruses target specific types of cells and so that leads of course to different symptoms. For instance, HIV targets cells are within the immune system and so you see symptoms related to that. 2) A lot of symptoms (fever, inflammation) aren\u2019t directly cause by the virus but by your bodies attempts to kill it."], "text_urls": [[]], "score": [11]}}, {"q_id": "9u2nlj", "category": "Repost", "title": "What is the difference between UK, Britain and England.", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["e9102mt", "e910isp", "e911cxp", "e910w2k", "e90zsie", "e91313m", "e918gqk", "e912vqq", "e910rqm", "e90z6hs", "e912h6c", "e9139m7", "e914fxs"], "text": ["The United Kingdom of Great Britain and Northern Ireland (often shortened to UK) is a group of 4 countries: England \ud83c\udff4\udb40\udc67\udb40\udc62\udb40\udc65\udb40\udc6e\udb40\udc67\udb40\udc7f, Scotland \ud83c\udff4\udb40\udc67\udb40\udc62\udb40\udc73\udb40\udc63\udb40\udc74\udb40\udc7f, Wales \ud83c\udff4\udb40\udc67\udb40\udc62\udb40\udc77\udb40\udc6c\udb40\udc73\udb40\udc7f and Northern Ireland. They each have their own flags, but also have the union flag to use when they\u2019re all together. \ud83c\uddec\ud83c\udde7 The British isles are a group of islands. The biggest one is called Great Britain. England, Scotland and Wales are in Great Britain. Northern Ireland is attached to the country Ireland \ud83c\uddee\ud83c\uddea on a separate island to the west of Great Britain. England is the biggest of the four countries and it has the most people. The capital of England is London. (The capital of Scotland is Edinburgh, the capital of Wales is Cardiff and the capital of Northern Ireland is Belfast)", "UK = England, Scotland, Wales And Northern Ireland Britain = England, Scotland, Wales. England = England", "GB - England, Scotland, Wales. The big island. UK - England, Scotland, Wales and Northern Ireland. The big island plus the bit at the top of the little island. England is just the biggest country.", "England is one of the four countries of the U.K. The other three are Scotland, Wales, and Northern Ireland. England, Scotland, and Wales are to be found on an island called Britain, or Great Britain. Northern Ireland is on a separate island called Ireland. With me so far? The confusion arises because people often use the terms UK and Britain interchangeably when referring to the UK. Americans tend to use England as well, again when referring to the UK. The full country name is: The United Kingdom of Great Britain and Northern Ireland. So you see how the U.K. and Great Britain are different. Great Britain (and island comprised of England, Scotland, and Wales) plus Northern Ireland, together make up the U.K.", "The United Kingdom of Great Britain and Northern Ireland is the entity recognised by the United Nations. Northern Ireland is in the north east of the island of Ireland and has its own governing Assembly that has power over devolved issues, but is ultimately subservient to the UK parliament at Westminster. The NI Assembly is currently not sitting for reasons I won't go into. The island of Great Britain consists of the countries of England, Scotland and Wales. Like Northern Ireland, Wales and Scotland have devolved parliaments. England is unique amongst the \"home nations\" in that it does not, and all laws pertaining to England are dealt with solely in Westminster. In modern culture, \"English\" and \"British\" tend to be used to mean the same thing - see the stereotype of polite tea drinkers in bowler hats. Scots, Irish and Welsh (to a lesser extent, as I dont think Wales is really represented culturally outside the UK) are generally shown as being distinct from the \"British\" stereotype. The terms \"UK\" and \"Britain\" are also generally both used to refer to the United Kingdom, in part because a large part of the British establishment tries to forget that Northern Ireland exists. Note: this is all off the top of my head stuff, so apologies for inaccuracies. Source: Am Scottish. Edit: as per comments below, I had referred to Northern Ireland as a province instead of a country.", "**United Kingdom:** Full name: United Kingdom of Great Britain and Northern Ireland A sovereign state that controls the island of Great Britain and outlying islands. It also still controls a bit of the island of Ireland. The rest of Ireland is an independent country since 1921. **Britain:** Normally used interchangeably with United Kingdom. Distinct from *Great Britain*, which refers to just the island. **England:** A country of the United Kingdom. It was once a separate kingdom by itself. The other countries are Scotland and Wales, which were also once separate (Kingdom of Scotland, Principality of Wales). Finally, there's Northern Ireland. Sometimes it's considered a country, sometimes a province, though neither are particularly accurate. Some further definitions: **Ireland:** The island of Ireland, located to the West of the island of Great Britain. **Ireland:** A sovereign state which currently controls most of the island of Ireland and outlying islands. Yes, the official name of Ireland is just Ireland. Sometimes *Republic of Ireland* is used to more be specific. However, it's used far more often than Irish people like. For Americans on here. Just because you have West Virginia doesn't mean that you need to have East Virginia, does it? It's really not that hard. **British Isles:** Just don't.", "CPG Grey has good video [The Difference between the United Kingdom, Great Britain and England Explained]( URL_0 ). It also gives brief explanation of the commonwealth, crown dependencies, territories/colonys", "In a month from now, when I finally understand this, I\u2019m going to move on to another ELI5 ...it\u2019ll be explanation of British money ...difference between, Pence, quid, pound, shilling, bob, tupence, etc etc", "England is the country at the south of the island, it\u2019s the one with London, Manchester, Newcastle, Liverpool etc. Great Britain is the island containing Wales, Scotland and England The United Kingdom of Great Britain and Northern Island is pretty self explanatory. It\u2019s the whole of the main island along with the top bit of Ireland where Belfast is located. The rest of Ireland where Dublin is a completely separate entity and is going to remain part of the EU after Brexit", "The United Kingdom is the official state. The UK is the one with a seat at the United Nations. England is a country within in the UK. It is very similar to a state in the United States, but has more power and history. Great Britain is the name of the island that England, Scotland, and Wales are located on. Great Britain contains almost all of the countries of the United Kingdom, expect for Northern Ireland.", "Bonus question. Why does Great Britain compete in the Olympics and not as individual countries?", "To put in a very simple format, it's the similar to asking \"What's the difference between the US, America and New York\"", "The official title of the nation is the United Kingdom of Great Britain and Northern Ireland, where Great Britain refers to the countries: Scotland, England and Wales. England is not an interchangeable word for the UK or GB even though this is a mistake that many people make, it is one of the countries within them. In other words, being English makes you British but being British does not make you English."], "text_urls": [[], [], [], [], [], [], ["https://youtu.be/rNu8XDBSn10"], [], [], [], [], [], []], "score": [4332, 365, 52, 45, 35, 27, 17, 10, 7, 6, 4, 3, 3]}}, {"q_id": "9ym46k", "category": "Repost", "title": "what causes the aurora borealis?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ea2esoe"], "text": ["The Sun emits a lot of charged particles, it's called the solar wind. As these high energy particles approach the Earth, the Earth's magnetic field channels them to the poles. At night, near the poles, these particles hit atoms in the atmosphere. The impact raises the energy state of the atom's electrons. When those electrons return to their normal orbits, they emit a photon. The \"Northern Lights\" (or southern lights if you prefer) is a label people have placed on these photons which appear at night. Also, this question is asked frequently. Search would get you better answers faster than asking again."], "text_urls": [[]], "score": [3]}}, {"q_id": "a9ypo3", "category": "Repost", "title": "Difference between work of FBI and CIA", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ecniel7", "ecniflk", "ecnljmq"], "text": ["FBI looks for bad guys inside the USA. CIA looks for bad guys outside the USA. FBI focuses primarily on crime. CIA focuses on our national interests on the world stage. [oversimplification, yes, but you know, you\u2019re 5]", "FBI is internal (collecting information about US citizens), CIA is international (gathering intelligence about foreign nationals).", "The FBI is the Federal Bureau of Investigation. They are one of several federal law enforcement agencies. Others federal law enforcement agencies include the DEA (the Drug Enforcement Agency), the ATF (the Bureau of Alcohol, Tobacco, Firearms, and Explosives), and the Secret Service, which in addition to protecting the president also deals with counterfeit money. In a lot of ways these agencies are just like local police departments. They investigate crimes that happen in the United States, and when they gather enough evidence they arrest the perpetrator and pass the case on to a prosecutor who will either agree to a plea deal or take them to trial. There are some limitations on the sorts of crimes these agencies can investigate, and they aren't involved at all in some duties typically associated with police departments, such as patrolling streets or writing traffic tickets. The CIA is the Central Intelligence Agency. It is one of several intelligence agencies in the United States. The other famous one is the NSA. The CIA are essentially spies. They're specifically supposed to gather information on foreign powers, be they actual nations or terrorist groups or movements within foreign nations. The CIA is specifically barred from operating within the United States, and they are unable to make an arrest (if they need someone arrested, they need to pass that on to a law enforcement agency, such as the FBI). Some foreign intelligence agencies that are equivalent to the US CIA would be the UK's MI6, Israel's Mossad, and in the past the USSR's KGB."], "text_urls": [[], [], []], "score": [39, 6, 5]}}, {"q_id": "a9zz3w", "category": "Repost", "title": "How do barcodes work? With billions of retail products available, how do companies ensure they have a unique barcode? Is there a central repository that generates them for anyone? If so, who maintains it?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ecnttez", "ecnu1a2"], "text": ["Barcodes are controlled by the non-profit organisation [GS1]( URL_1 ). Basically, you buy a barcode \"block\" from GS1, and then you have a certain amount of barcodes depending on how much money you pay them. [Wendover Productions]( URL_0 ) have a 5 minute video about barcodes as well I'd recommend watching.", "Barcodes themselves basically just store text in the form of a barcode. [You can make your own here]( URL_0 ). QR codes are essentially 2D barcodes and do the same thing. As far as barcodes on PRODUCTS go, there's an accepted standard used in many countries called UPC. There's lots of details in here: URL_1"], "text_urls": [["https://www.youtube.com/watch?v=XPuTZMp-HE8", "https://www.gs1.org/standards/barcodes/ean-upc"], ["https://www.barcodesinc.com/generator/index.php", "https://en.wikipedia.org/wiki/Universal_Product_Code"]], "score": [31, 9]}}, {"q_id": "aa9qir", "category": "Repost", "title": "Why do some countries drive on the right, while some on the left? And also why do they drive on the right if the driver's seat is on the left, and vice versa?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ecq24wo", "ecqh295", "ecq2zfk", "ecqi6cb"], "text": ["I can only answer the second part of the question The reason the driver's seat is on the left of right-driving roads is so that the driver is seated as close as possible to the middle of the road, giving him or her the best visibility. If your seat was on the right while driving on the right side if the road you'd be too far from the opposite lane to correctly calculate distances", "These things are often multifaceted. Some of it also comes from the belligerence of Napoleon and his armies. The norm at the time was to walk on the left, ride on the left etc (for all those reasons mentioned about swords but also about just meeting people, shaking hands). It was a norm for a really long time for many reasons. Napoleon ordered his forces to march on the right specifically to cause conflict and make other people move as a symbol of dominance. England being the main ones in Europe to defeat his forces, continued happily on the left, while it marked a huge shift for a lot of the rest of Europe, and then the world at large.", "I can answer the first part. It dates back to the days where cars didn't exist and everyone used horses for transportation. Most people travelled on the left hand side. As most places were lawless and guns were not yet in production, people carried swords. As most people were right handed, it made sense for them to travel on the left hand side as they could attack other horsemen coming the opposite way using their stronger hand to control the sword. This however evolved when countries began hauling heavy materials around using horse pulled coaches. They were only made with a left hand seat (IIRC) and drivers needed to ensure they would not hit any oncoming coaches, so preferred to travel on the right hand side and have others pass them on the left so they could lean over and check that they aren't going to hit any oncoming vehicles. Thus it evolved that some countries drove on the right and others remained on the left.", "The UK has historicly driven on the left because it allowed thoes riding horses and drawing carts to easily draw and hold a sword in the right hand. Other countries may have adopted this practice due to British colonialism or for other reasons."], "text_urls": [[], [], [], []], "score": [46, 13, 5, 4]}}, {"q_id": "aayelc", "category": "Repost", "title": "How do speakers replicate sound?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ecwelf9", "ecw5alz", "ecw0cbh", "ecw0hn2"], "text": ["Shake a piece of paper, it makes a noise. Speakers use magnets and electricity to shake the paper really fast in a really specific way to make the sound you want it to.", "Sound is just pressure waves in air, a vibration of the medium that carries it. A speaker then is just a mechanism to vibrate air. This is most commonly achieved with a light cone of somewhat flexible material (often paper or thin plastic) which has a coil of wire in the center. It is set into a frame which has a permanent magnet placed close to the coil of wire. When current is passed through the wire coil it creates a magnetic field that pushes or pulls on the field from the permanent magnet, pushing or pulling the cone along with it. By varying the current and resulting magnetic field the cone can be caused to vibrate which causes the air to vibrate, which is sound.", "Sound is converted into electrical signals. Those signals are fed into the voice coil of the speaker, generating a magnetic Field. That magnetic Field, with the help of the magnet moves the cone of the speaker generating sound waves.", "The speaker cone moves backwards and forwards creating pressure waves in the air that reach our ears as sound. The speaker cone is fed with a waveform that is an electronic version of the sound to be reproduced. The coil on the cone is in a magnetic field so it moves due to the interaction of that with the current flowing through it."], "text_urls": [[], [], [], []], "score": [5, 5, 3, 3]}}, {"q_id": "ab2ncv", "category": "Repost", "title": "Why can you HEAR the sound of tap water changing temperature?", "title_urls": {"url": []}, "selftext": "Turn on hot water. It starts cold. When it finally gets warm, you can *hear* the change. Why?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ecx0u07", "ecxa2a7", "ecx0tov", "ecxeeuj", "ecxam5f", "ecy00wu", "ecxcgfi", "ecxbpl6", "ecx5bzv", "ecxgkqq"], "text": ["Hot water is less viscous. That is, it flows more easily than cold water. You can hear the difference in the water's thickness as it goes through the pipes and out the faucet.", "The heat from the hot water also causes faucet parts to expand . This is particularly true with old style rubber washers. This can cause different foe rates .", "The water density and thus flow changes. It resonates differently with the metal edges of the tap. Unless you mean hearing the flow through the separate hot water pipe as an additional sound which is also possible depending on your set up.", "Something very easy to understand that has yet to be mentioned is the local source of the water. Your cold water is coming in straight from your water source and your hot water is most likely coming from a water heater that is fed by your cold water source. You could be hearing the different water supply lines. The noise can be explained in all of the other posts mentioning a different viscosity for different temperatures etc.", "In all honesty, out of the faucet, you're probably hearing a different configuration of pipes. Not temperature differential.", "It's partially due to surface tension of water dropping as the temperature rises. When the surface tension of a liquid is high, it wants to reduce its surface area and curls up into larger spherical shapes (spheres have the lowest surface are per volume), but when the surface tension is lower, water can break into smaller droplets. So when you turn on the faucet, water flows in larger chunks and smash onto the sink. As the water heats up, these chunks/droplets get smaller and get sprayed onto the sink.", "Think about what makes water hot. The more energy in a material, the more spaced out its atoms are. That said, take a bag and fill it with something. Tie it tight so that the contents are firmly packed. Drop it from a set height. Now, take the same bag, and tie it loosely such that the contents have plenty of room to move, and repeat. You should hear a massive difference, particularly the tighter bundled drop should have a heavier sound to it. This is because being tighter together, more energy is transferring into a smaller area at a faster rate. That's why hot water has an almost floaty sound to it. You can even make cold water sound \"hotter\" by installing a mesh onto a tap that's more fine than currently installed and comparing the sound of hot with standard mesh to cold with fine mesh - since the mesh is creating gaps in the water.", "What about steam? As the flowing water increases temp steam begins to fill the sink / pot / vessel. Would this contribute to a dampening (heh heh) effect on the higher frequencies in particular?", "Cold water is more viscous and better at retaining air than hot water is. As water flows past a faucet aerator, cold water will entrain more air than hot water. Because it\u2019s more viscous, it also flows through the aerator more slowly. The change in sound is because, due to lower viscosity and less air entrainment, hot water flows faster through a faucet aerator than cold water.", "Everything vibrates, things that are hot vibrate faster than when they are cold. (I am unsure if there is a material that doesn\u2019t follow this rule)."], "text_urls": [[], [], [], [], [], [], [], [], [], []], "score": [8780, 345, 82, 45, 11, 9, 8, 7, 6, 3]}}, {"q_id": "7uf1x1", "category": "Repost", "title": "why do different languages (English, Russian, Thai) use different alphabets but use the same symbols for numbers (1,2,3)", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dtjth6q", "dtjv2mt", "dtjtkct", "dtjvdc4"], "text": ["Short answer: Arabic numbers became really popular among mathematicians and merchants and spread around the world. It was easier for everyone to stick to the same system.", "There are Thai number characters. Following characters is 0 to 9. \u0e50\u0e51\u0e52\u0e53\u0e54\u0e55\u0e56\u0e57\u0e58\u0e59 But we use Arabic number for almost everything.", "Because we all use Arabic numerals now. Way back when many of these areas used different numerals (such as Roman). When the Renaissance occurred it stemmed due to knowledge coming from the Arab world. Thus many advancements in math and science were gained via this route and Europeans adopted the numerals.", "Chinese (and I believe Japanese) use \u4e00\u4e8c\u4e09\u56db\u4e94\u516d\u4e03\u516b\u4e5d\u5341 for 1 to 10. But the Arabic style is generally easier to use 798 is easier to write than \u4e03\u767e\u4e5d\u5341\u516b for instance. It also helps to make mathematics more universal, an English speaker could pretty easily understand the maths of a paper written in Chinese, even if the context is unclear. Edit: I can't number it seems."], "text_urls": [[], [], [], []], "score": [94, 24, 9, 7]}}, {"q_id": "7ufcqg", "category": "Repost", "title": "What is that weird thing that you see in your eyes after looking at a bright light?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dtjwmht"], "text": ["A couple things actually... \"Floaters\" are the shadows cast by bits of debris and protein clumps floating around between the retina and the center of the eye. These are completely harmless and you can see them fumbling around your eyes from time to time. In your eyes you also have capillaries(very thin blood vessels,) and through these, red and white blood cells are carried. Because white blood cells are larger and of more abnormal shape, they tend to not get filtered by your brain when processing what your eyes are seeing, they just look like white specks following a track. Finally, when you rub your eyes, you're physically altering pressure in your eyes and stimulating photo-receptors and releasing chemicals called phosphenes in your brain. These cause the pretty colors and weird shapes much like applying pressure to an LCD screen. \"Picture burn\" which is what I believe you're referring to is simply the heavy intake of a bright source of light(i.e. the sun) and having the image retained in the form of a black splotch. This is what I believe to be the work of your brain filtering that area of your vision in order to preserve the eye(which is ironic because it only allows you to look at the sun for longer-causing more damage) [A video by Tom Scott]( URL_0 ) explains this well."], "text_urls": [["https://www.youtube.com/watch?v=WKQT1MXfasM"]], "score": [3]}}, {"q_id": "7ufysh", "category": "Repost", "title": "Why is it that if you put salt in ice water, it makes it colder, but when it snows, you use salt to melt the ice?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dtk1gg3", "dtk0xuj"], "text": ["> Why is it that if you put salt in ice water, it makes it colder It doesn't make it colder. It allows separate cooling processes to make the water colder than the normal freezing point of water without it freezing. > but when it snows, you use salt to melt the ice? For the reason stated above. Saltwater can get colder than normal water without freezing. When you put salt on ice, the salt mixes with the ice, causing it to melt (since the newly-formed salt water doesn't freeze at the current temperature). The important thing to know is that the ice isn't melting because it's getting warmer, because it's *not* getting warmer. It's melting because you've changing it into something that can't be a solid at the current temperature.", "Because putting salt in ice water doesn't make it colder, it just lowers the freezing temperature which melts the ice."], "text_urls": [[], []], "score": [8, 5]}}, {"q_id": "7ugmy7", "category": "Repost", "title": "How do Cell phone towers work/get their service?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dtk7k1d"], "text": ["I dunno how ELI5 you're looking for. But basically a cellphone is actually a radio transceiver and the cell towers have transceivers as well. Each tower is ultimately wired up to some form of a landline in order to provide telephone and Internet service. As you move around, your cellphone connects to the tower that is nearest, or otherwise has the strongest signal. You can be mid-call or the like while driving or walking, and if the tower you're connected to gets to be too distant or weak, it will disconnect and start transmitting and receiving to/from another closer/stronger tower. The methods cellphones use are able to make this switch between towers without you noticing any interruption in your call, or movie, or whatever."], "text_urls": [[]], "score": [3]}}, {"q_id": "7uhczu", "category": "Repost", "title": "How do sewage systems function in freezing conditions during the winter time? Smaller pipes can be insulated, but what\u2019s preventing liquid waste from freezing up in the larger sewer pathways?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dtkbva4"], "text": ["Ground keeps it naturally insulated. Typically lines are buried below any perma frost or at depths where it won\u2019t freeze come winter. Throw in that water and waste going into the lines is also warmer than freezing and it actually keeps things warm enough not to freeze. And finally sewer lines having moving water and waste. As long as there is flow, combined with the above reasons, it becomes quite hard for water to freeze in the sewer line."], "text_urls": [[]], "score": [9]}}, {"q_id": "7uhlcf", "category": "Repost", "title": "How is it possible that most of the items in online Chinese websites can be shipped for free?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dtkch1g", "dtkcew0"], "text": ["Also, you might notice you always get something extra in your package. They do that because they don't have to pay for customs if there is a gift in the package.", "The people sending you the package is paying for the shipping as well, it looks \"free\" to you but the price of the shipping is just packaged with the price of the item you are buying. If you look through different eBay listings where they sell the same product you will see that the items with \"free shipping\" cost more. \"free shipping\" looks way better than having to pay for shipping. It's a way for the seller to bait you"], "text_urls": [[], []], "score": [3, 3]}}, {"q_id": "7uko1k", "category": "Repost", "title": "How exactly does the hardware of a computer work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dtl0f18"], "text": ["To explain it would take, like, a college degree\u2019s worth of explaining. At the core of how all the parts work are the flow of electricity, and logic gates. These are little physical bits in those small chips. They take in voltage through two little wires, and have a third leading out. Depending on which kind of gate it is and which current is active, the third will or won\u2019t pass on the current according to rules. These rules correspond with Boolean logic (binary logic) rules, and clever combinations of those gates basically makes a computer. An example is an OR gate: of either or both of the incoming wires has voltage, the gate passes in the voltage. An AND gate would only do so if *both* incoming wires had voltage. What we think of as addition can be represented with combinations of these gates. Same with every other math operation. Memory and disk storage is just to record data, printers and speakers and monitors just report data to the user, but under all that, it\u2019s lots and lots of little logic gates, and clever programming."], "text_urls": [[]], "score": [4]}}, {"q_id": "7ul320", "category": "Repost", "title": "Why are some eggs brown and some white and what's the difference?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dtl3h91"], "text": ["The difference is the momma chicken. It sounds almost too simple, but white chickens make white eggs. Other-colored chickens make brown ones. That\u2019s it. If the chicken is speckled or part white, the color of its earlobes is the indicator. Fun fact."], "text_urls": [[]], "score": [35]}}, {"q_id": "7ulknb", "category": "Repost", "title": "Is there any actual scientific basis behind the multi-universe theories, or is it just smart speculation?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dtl800o", "dtl9g0o"], "text": ["Multiverse theories spawned from string theory as well as being a possible resolution to wavefunction collapse. String theory cannot be proven but it also hasn\u2019t been disproven yet. It\u2019s important for string theory that [Lagrange invariants]( URL_0 ) stay invariant through experimentation. The problem is that multiverses are untestable, so they fall outside of the realm of science.", "As u/mvs1234 indicated, multiverses are speculation at this point. There are some theories that indicate possible weak interactions between universes (like gravitational interactions) and that those interactions may be responsible for various things like the [CMB Cold Spot]( URL_0 ). Of course, if we can interact with this other universe, then one can argue it really isn't a separate universe. At this point though, you are just arguing over definitions of 'universe'."], "text_urls": [["https://en.m.wikipedia.org/wiki/Lagrange_invariant"], ["https://en.wikipedia.org/wiki/CMB_cold_spot"]], "score": [17, 3]}}, {"q_id": "7umlre", "category": "Repost", "title": "How do astronomers find planets beyond our solar system and so far away?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dtlhepx", "dtlgcfp"], "text": ["There are a few ways: **One** way to make sense of the gravitational interaction between a planet and a star is to imagine a game of tug-of-war. On one side, you have the star - a massive object with a really powerful gravitational field. On the other side, you have the planet, much smaller, with a whole lot less gravity. We know who wins this game - the star. That's why planets orbit stars and not the other way around. But even though the planet is small, it still has some gravitational force. It still has an effect on its host star, even if that effect is much less pronounced than the one the star has on the planet. The planet's gravity causes the star to 'wobble'\ufffdaround a little bit. As you might imagine, the bigger the planet, the bigger the effect it has on its star. Small planets, like Earth, make their stars only wobble a tiny bit. Bigger planets, like Jupiter, have a much stronger effect. **DIGGING INTO THE DOPPLER DATA** Wobbling stars are great for finding exoplanets, but how do we see the wobbling stars? The method used is one called 'Doppler shift'\ufffd. It's named after the physicist who figured it out about 150 years ago. Energy - sound, radio waves, heat, and light - moves in waves. Those waves can be stretched and squeezed, based on the movement of the object that's producing them. You may not know it, but you've probably experienced the Doppler effect before. Have you ever noticed how the sound of an ambulance passing you on the street gets higher in pitch as it gets close to you, and then lower in pitch as it speeds away? The reason is because when an object that emits energy (like an ambulance speaker or a massive, burning star) moves closer to you, the waves bunch up and squish together. And when the object is moving away, the waves stretch out. Those changes in the wavelength change how we perceive the energy that we're seeing or listening to. As sound waves scrunch together, they sound higher in pitch. And when visible light waves scrunch together, they look more blue in color. When sound waves stretch out, they sound lower in pitch. And when visible light waves stretch out, they make an object look more reddish. This change in color is called 'redshift', and scientists can use it to see if an object in the sky is moving towards us or farther away.", "They examine the light from stars. The gravity of a large planet orbiting a star may cause the star to wobble slightly. Or when a planet transits between the star and us, we can see the light of the star become slightly dimmer and the frequency of the wavelengths of light may change if some of the light passes through an atmosphere."], "text_urls": [[], []], "score": [8, 7]}}, {"q_id": "7unfi6", "category": "Repost", "title": "How does one way glass work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dtlnley", "dtlndqf"], "text": ["The explanation provided by u/Pegajace is only partially true: URL_0", "Ever go to look out the window on a dark night, but discover that it's almost impossible to see outside because the reflection of the interior is so much brighter? One-way glass is just regular glass with a bright room on one side and a dark room on the other."], "text_urls": [["https://en.wikipedia.org/wiki/One-way_mirror"], []], "score": [6, 3]}}, {"q_id": "7uq7za", "category": "Repost", "title": "How are off shore country boundaries figured out? Past a certain point, does the ocean just turn to lawless waters?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dtma24s", "dtmg1vd", "dtmqv1n"], "text": ["Nowadays, it's controlled by the United Nations Convention on the Law of the Sea, which says that countries can claim up to 12 nautical miles from their coastline as territorial waters, which means the country has complete control over what happens there. Waters further out are subject to less and less power until you reach 200 nautical miles from the shore, at which point it becomes international waters where no country has any sovereignty at all (though various international treaties still apply).", "It is determined by whichever nation is willing to fight for it and is able to win. It really is that simple. Various treaties do exist but they are violated pretty routinely, and are mostly invoked for PR purposes. The bottom line is that if you are willing to fight for it and have a good shot at winning, it's yours. Case in point - China has repeatedly stated it has territorial rights over some small islands in the South China Sea that do not agree with international treaties. It has also claimed all of Taiwan as a \"province\". Nobody is willing to really recognize this and so far nobody has fought over it. Another case - back when Muammar Ghaddafi was running Libya, they claimed a large section of the Mediterranean that nobody honored. The US in particular conducted naval operations routinely, and the one time Libya tried to defend it they were comprehensively crushed. Might makes right on the high seas.", "Thank you for the informative answers! Follow up question, when something particularly bad happens in international waters, to whom is the investigation dolled out to? Is it to whichever country is closest, or does the UN collectively take a look at it? Edit: word typos"], "text_urls": [[], [], []], "score": [25, 9, 4]}}, {"q_id": "7us5rv", "category": "Repost", "title": "how do radio stations know how many people are listening in on them?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dtmofob", "dtmop3i", "dtmoo47"], "text": ["Same way it works for broadcast TV. A small number of people are chosen to be the statistical sample and those people are given special receivers to record their listening habits.", "In addition to what littoraldaydreamer said, many advertisers include \u2018promo codes\u2019 that are different for each show or station, the use of these codes allows them to very directly track their customer\u2019s listening habits.", "Nielsen conducts radio market surveys to provide stations with rankings and demographic information. Stations use this to set rates and advertise their services to potential customers. It will include time slot/host audiences as well as demographics (mostly age) for the listening group."], "text_urls": [[], [], []], "score": [11, 3, 3]}}, {"q_id": "7us6lq", "category": "Repost", "title": "The advantages and disadvantages of a quad/multi-copter over a helicopter", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dtmorwy", "dtmti2c", "dtmwk88", "dtn8mcf"], "text": ["Quadcopters are a very inefficient design from both a power use and a lift capacity standpoint. Compared to traditional single or tandem rotor helicopters though they are much easier to fly with simple controls.", "Quadcopters are really easy to fly and are really easy to program a computer to fly. Left, right, front, back, up down, it is a simple matter of altering prop speed. A traditional helicopter has to worry about momentum and turning radius and all kinds of other things. The tradeoff is that a quadcopter is much less efficient. They take more energy to do less, and pound for pound, they are slower and have less range and lifting power.", "Quadcopters are inefficient but you only have to adjust power to 4 very small and fast reacting motors to maneuver. No fancy control linkages needed or control surfaces outside of your 4 motors and propellers. With a regular copter, they use a very complex set of linkages to tilt each blade as it goes around its rotation and back again for maneuvering, as well as increase/decrease the overall tilt of all blades to gain/lose altitude. Another tail rotar is required (or dual main rotars spinning in opposite directions) to compensate for blade torque. Regular copters often use turbine engines that take incredibly long (on the order of 10+ seconds) to adjust RPM from max operating RPM to min operating RPM, so adjusting RPM of the motors to control lift is just not an option. These however are very efficient sources of energy (Gasoline stores so much more energy per pound then a battery) and turbines are especially efficient if run only at a fixed RPM. a tiny motor like on a quadcopter is often electric and can throttled to full RPM/0RPM and even reverse within a second. They can even recover energy back into the battery by slowing down the motor, slowing the motor down much faster then if the motor was just no longer powered. You could almost think of a helicopter as having multiple independent blades instead of a rotar, and the main difference being between a quadcopter and helicopter being that a quadcopter controls by altering the RPM of its blades while a helicopter alters the pitch of its blades. PS: One of the main reasons quadcopters are inefficient is because larger blades are more efficient and a quadcopter uses smaller blades.", "The primary advantage of a quadcopter is simplicity. Control of the craft is achieved entirely by varying the speed of motors, and the only moving parts are the rotors themselves. By contact, and helicopter needs to be able to vary the pitch of the blades individually in order to control the pitch of the blades individually in order to control the pitch and roll of the aircraft, and this is done through a system of linkages. That makes for a substantially more complex design, both to maintain and to fly. But a single rotor is more efficient than four smaller ones for the same lift capacity. This is less important for a drone that can just land when it runs out of battery than a full size aircraft where range is important. Also, a quadcopter with its fixed pitch blades cannot autorotate - if the power fails, it will crash. This gives helicopters a safety advantage."], "text_urls": [[], [], [], []], "score": [67, 27, 25, 3]}}, {"q_id": "7uu5r0", "category": "Repost", "title": "Why do photos of computer screens have odd lines on them?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dtn7wbt"], "text": ["You're seeing a [Moir\u00e9 pattern]( URL_0 ) caused by interference between the grids of your photo's pixels and the computer screen's pixels. You can see similar Moir\u00e9 patterns by looking through two ordinary window screens (the kind you use to keep out bugs) one on top of the other."], "text_urls": [["https://en.wikipedia.org/wiki/Moir\u00e9_pattern"]], "score": [17]}}, {"q_id": "7uvupc", "category": "Repost", "title": "How does a phone or laptop measure the percentage charge of its battery?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dtnjy7h"], "text": ["Batteries lose voltage as they discharge: they aren\u2019t giving out electricity as well as when they are full. A device can measure that, and calculate how dead a battery is based on its particular voltage."], "text_urls": [[]], "score": [3]}}, {"q_id": "7uxal3", "category": "Repost", "title": "How is wind generated? / Where does wind come from?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dtnw8bp"], "text": ["Air moves from areas of high pressure to areas of low pressure. Sunlight heats the ground in an area, and the ground heats up the air above it. The hot air moves upwards (because it's less dense, and thus lighter - this is why hot air balloons rise up), and the air in the surrounding areas moves in (horizontally) to take its place. Horizontal air movement is wind. The Earth rotates, and the solid ground rotates with it, but air is kind-of free to move around, being a gas. The rotation of the Earth and the areas heated up by the Sun (during the day) and cooled by the lack of Sun (at night) determine [global wind patterns]( URL_0 ). Look at the pictures in that link, hot air moves up and then comes back down when it gets cold, and also horizontally it moves around in big circles. Around the globe."], "text_urls": [["https://en.wikipedia.org/wiki/Global_wind_patterns"]], "score": [3]}}, {"q_id": "7uyqeo", "category": "Repost", "title": "Why do people take the time to make computer viruses? It seems like a lot of work just to be a jerk, do they make money? How?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dto7gsh", "dto66u1", "dto625y", "dto8ujb", "dto6eb3", "dto754o", "dto7y05", "dto9e2c"], "text": ["Most computer viruses are created with the intent to profit from them. This can take a few different forms though. Ransomeware encrypts your files until you pay the ransom, this is perhaps the largest threat in recent memory. Others search for data related to banking or other profitable information. Some enable the creator to take over the computer and use it's resources and/or network connection for other nefarious purposes. All that aside, most are created with some form of profit in mind. Then there are those who create them \"because they can\". Ever done something on a dare or because you wanted to see if you could or how far you could go? For some people creating viruses is like that. How many computers can they infect? Are they able to make a virus go worldwide? Personal or public prestige and challenge, et cetera. And then there's the even smaller subset of white hat viruses. Yeah, that's a thing. There are people who create viruses to patch security vulnerabilities. Example: URL_0 And sure, some create them for fun. It's not terribly difficult if you know your programming. Since a rather large number of people don't actually update their computers often, **known** security vulnerabilities are easily exploited. Remember WannaCry? The patch for that vulnerability was released **several months** before it became a worldwide problem and gained national news sensationalism. Software providers will discover a vulnerability, release a patch for it, then release the details for the vulnerability and patch some time later after giving people a reasonable amount of time to update their systems. This release also gives hackers a roadmap on how to attack those *unpatched* systems still online. Lastly there's the viruses that search for information. Whether government secrets or university research or protected business info, viruses can look for info and report matches back to the creator/controller. I'm not even going to talk about the nation-state created viruses. Bottom line is it can be for any reason in the human psyche, but mostly it's for profit. Turn on automatic updates. Source: am slightly drunk cybersecurity major.", "A lot of viruses are created ethically in order to test security systems, antivirus systems, malware detection systems, etc. Far more so than are created to actually be a threat to the average consumer. Beyond that, a lot of viruses/malware are created in order to mine data about people, which is then sold to larger marketing companies so that they can target ads to your individual preferences and increase sales. It's very rare for a virus creator to actually be the one targeting you specifically, and that'll only really happen to companies/corporations in order to get a quick buck out of selling them the antivirus counterpart. \"Give me $5,000 and I'll give you the program that will fix this virus that has completely shut down your network.\" Large companies/corporations will pay off that $5,000 without a thought because they realize that it's a drop in the bucket compared to how much money they're losing by being unable to use their computers.", "They sometimes say you have to give your bank accounts detail or make a phone call to get rid of the virus or otherwise they just find it funny", "Some people create viruses for shits and giggles. They\u2019ll spend five minutes coding something that will turn your computer off or something when you open it, and that\u2019s all (Source: I have friends who do this all the time) Others just want to watch the world burn On a serious note, however, viruses that make money usually steal your information (ex: credit card, name and birthday, address) and sell it to marketers. Others encrypt all your files and demand a ransom for them.", "To make money. Some people create malware to trick you to run it so they can use your computer to spread more malware and spam and they rent them out to others. Some make crypto lockers that encrypt all your data and you have to pay them to get your files unlocked. Some make malware to manipulate your banking software so they can steal money. Some make malware to manipulate Facebook or Twitter to fuck with the elections in other countries. It used to be research and see what cool stuff I can do but these days it's mostly money.", "People have already mentioned that ransomware and spyware can be used to make money. Another popular way to make money off of malware is bitcoin mining. That's where the virus is making your computer mine bitcons, and send them to the virus creator. Of course, another reason people make malware is when they work for an organization that wants to sabotage another organization electronically. An example of this is the virus that broke the Iranian nuclear program a while back.", "Sometimes they're doing it because the government employs them to do so and they see it as their patriotic duty to make centrifuges in Iran blow up. (cf Stuxnet)", "Viruses take advantage of mistakes in computer programs. They\u2019re used by criminals for the same reason as other forms of crime. Usually to earn money, occasionally for ideological reasons. People can make money finding those mistakes and selling them. Sometimes they are good people who sell the mistake to the people who created the program. Sometimes they sell to the highest bidder, often to people who make viruses. Sometimes the person will create the virus themselves. Some will use your computer to do work that earns them money kind of like slavery. Some will collect information that can be sold for money kind of like burglary. And some will hide your information and try to sell it back to you kind of like kidnapping. People who aren\u2019t in it for the money might do it for the challenge, to see their work spread and get talked about, or even to do damage to property."], "text_urls": [["http://www.ibtimes.co.uk/linux-wifatch-routers-hacked-by-white-hat-virus-that-makes-them-more-secure-against-malware-1522214"], [], [], [], [], [], [], []], "score": [1188, 53, 28, 20, 8, 6, 4, 3]}}, {"q_id": "7uzyd6", "category": "Repost", "title": "Brownian Motion", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dtofigl"], "text": ["Molecules in a fluid are always moving around. They bounce off of each other, and they bounce off of anything solid that they hit. At any given moment, a solid object will have more molecules bouncing off of one side than the other. For something big like a person, the difference is insignificant, but for something tiny like a single-celled organism, you can actually have enough extra water molecules bouncing off of one side to give the object a perceptible shove. It all averages out in the long run, but if you look at a tiny thing in a drop of water with a microscope, you can see it vibrating as it gets bounced around by the random water molecules."], "text_urls": [[]], "score": [3]}}, {"q_id": "7v08an", "category": "Repost", "title": "Why can't we hold our breath to death?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dtohdel", "dtohgwq"], "text": ["It is. You are correct. Deprived of oxygen to the brain a person will lose consciousness. Without the forced stoppage of breathing the autonomic system takes over (breathing is default, rather than *not* breathing, you don't have to decide to breathe it just happens) and the person will not die.", "Because breathing is a non-voluntary motor skill... we do it without having to be awake and thinking about it. Also the default setting is 'On' if you are determined enough I suppose you could hold your breath until you lost consciousness but then the default setting would kick in and you would start breathing again."], "text_urls": [[], []], "score": [5, 3]}}, {"q_id": "7v09ne", "category": "Repost", "title": "Why does drinking carbonated drinks help with stomach aches?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dtohhmn"], "text": ["because the carbon dioxide helps your stomach increase gastric secretions and stimulates the secretion of the intrinsic factor protein which helps in digestion."], "text_urls": [[]], "score": [27]}}, {"q_id": "7v5bzj", "category": "Repost", "title": "What exactly causes the feeling of being \"dizzy\" when getting up quickly?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dtpmo9h"], "text": ["It's called orthostatic hypotension. It's just your blood following gravity and pooling in your body (and your legs in particular) thus reducing the flow to your brain, which in turn signals it by making you feel dizzy. You feel dizzy and eventually faint because by falling down you remove the gravity factor and it's easier for blood to reach the brain. It's a very common experience, particularly in the elderly. If it happens regularly, or you faint, you might want to get it checked."], "text_urls": [[]], "score": [3]}}, {"q_id": "7v5jhu", "category": "Repost", "title": "why a lot of watches with Roman numerals use 'IIII' for the number 4 instead of 'IV'.", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dtpobh4"], "text": ["They are made by people that do not know Roman Numeral (generally in asia) and it is actually a sign of the watch being low quality."], "text_urls": [[]], "score": [3]}}, {"q_id": "7v7a6h", "category": "Repost", "title": "How did they print pictures in early days of newspaper ? I recently watched the movie The Post and the entire time I was wondering how they printed pictures with the movable metal type ?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dtq0azw", "dtqp0ik", "dtq6iek", "dtql682"], "text": ["They used a filter on photos that broke the image into tiny dots, called [halftone]( URL_0 ). You aren't actually seeing grey or varying shades of black, but dots getting smaller and further apart to create the illusion of grey tones. The image was then transferred to a plate, right along with the type, that was then inked and the image transferred to the paper by pressing the inked plate against it.", "An earlier method would actually engrave lines into a soft metal plate. In high school, I worked at the local weekly paper ... the paper used linotypes up until about 1971 or so. My job was to lube the Linotypes, break down the chases of type of that week's edition, melt down the type slugs into ingots for the LinoTypes, cast the stereotyped ads for the coming edition, and generally clean the place out. For photos, they had a small lathe. On one end, you wrapped the photo around the lathe cylinder. On the other end of the cylinder, you wrapped a sheet of soft metal. The end with the photo had a photocell to sense light and dark areas. The other end had a pin-type cutter. For dark areas, the cutter cut less deeply, lighter more so. Then you turned the machine on. A screw drive advanced the cutter and photocell along the length of the lathe. When it hit the end, you had a print ready photo engraving. This also worked with sending images over the telephone or telegraph lines ... kind of like an early FAX machine. An old newsreel clip (ca 1937) showing the technology ... URL_2 The machine demo starts at about 3:40. Important international news photos would often have a cut-line, \"AP WirePhoto\" to impress you with the news organization's global reach. Like in the 60's when a grainy, blurred news clip from somewhere else on the planet would have the overlay, \"Live, via satellite.\" When the local paper went to the offset printing process, we started using the half-tone process. For display advertising, the ad agency would send us heavy cardboard mats with the text and images pressed into the cardboard. These were called stereotypes. We would use those to cast a thin sheet of lead holding the image and text. The images were made using the half-tone process. Halftoning used a rather expensive chemical etching process to make the image. It did make for much higher quality images used in book printing. The photo lathe was pretty cheap and easy to run. Dang, looks like that company is still in business, URL_0 A more detailed description from an old Popular Science issue (1933) URL_1 Etaoin Shrdlu ;D", "Newspaper photos are still printed with halftones today. Halftones are a relatively recent technology, began to be widely used in newspapers in the 30s I think. Halftones are not feasible with metal type, what few pictures early newspapers contained were metal engravings. I haven't seen the movie and don't know what \"early days of newspaper\" means here exactly.", "Just for context, The Post is not set in \"the early days of newspapers.\" Papers have been printed for more than 300 years, images have been printed in papers for nearly as long. Halftone printing has been used in papers for almost 150 years."], "text_urls": [["https://d2gg9evh47fn9z.cloudfront.net/800px_COLOURBOX18748446.jpg"], ["http://www.graphicelectronics.com/engraving.html", "https://books.google.com/books?id=QuIDAAAAMBAJ&amp;lpg=PA34&amp;ots=LOjLe7rqCe&amp;dq=photo%20engraving%20lathe&amp;pg=PA34#v=onepage&amp;q=photo%20engraving%20lathe&amp;f=false", "https://www.youtube.com/watch?v=lthb8d_u1Kg"], [], []], "score": [362, 19, 14, 7]}}, {"q_id": "7vbuyn", "category": "Repost", "title": "How do solar panels convert light to electricity?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dtr4662", "dtr5kai"], "text": ["In certain compounds, exposure to certain colors of light will cause electrons to be pushed in one direction. How hard they're pushed is the voltage, and voltage pushing electrons through a wire is what you normally think of as electricity. So sandwiching wires onto the right compound, then exposing that cell to light is a really simplified version of solar power. And if that seems like a shitty explanation, that's cause it is. Einstein literally won a Nobel prize for explaining how it works. Not for any of that e=mc^2 stuff; he won his Nobel for explaining the photoelectric effect.", "The fundamental process is known as the photoelectric effect. Electrons are bound to the nucleus of an atom, and require energy to escape. If you give them energy, they can climb up the energy states of the atom (like rungs on a ladder, if we're only considering the energy picture) until they become too energetic for their attraction to the nucleus to hold them still. When this happens, the electron is free from the atom and can move around unrestrained. One way to make electrons more energetic is to have them absorb photons. There are certain rules to what kinds of photons (in terms of frequency and energy contained) an electron bound to a certain atom can absorb, and at what energy levels, but we don't have to get into that. It is sufficient to say that you can hit an atom with photons in order to free electrons from it. If you place an electric field across the surface of the group of atoms, this field will pull the free electrons away from the atoms. This stream of electrons coming off of atoms and being pulled in the same direction forms a DC current. Edit: Removed unnecessary tangent"], "text_urls": [[], []], "score": [7, 3]}}, {"q_id": "7vcia1", "category": "Repost", "title": "What exactly is fire?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dtr9fea"], "text": ["Fire is when gases boiling off (yes, wood \u201csweats\u201d chemicals off just before that gas actually combusts) oxidize (combine with oxygen in the air) so quickly that it generates enough heat to keep boiling off more chemicals, and makes the gases glow (the same way a hot iron or electric stove glows red, but brighter and hotter). What you see is just gas that is rusting so quickly it\u2019s hot. It\u2019s literally just hot gas."], "text_urls": [[]], "score": [9]}}, {"q_id": "7vmypr", "category": "Repost", "title": "What exactly is the Dow, and when should I start really worrying about it dropping?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dtti9fj"], "text": ["When you start hearing about massive layoffs and banks nearing collapse. Market was getting very very hot, and was moving further away from fundamentals. This correction isn't that surprising."], "text_urls": [[]], "score": [6]}}, {"q_id": "7vmyzp", "category": "Repost", "title": "How can any storage device keep information once unplugged from the computer?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dtthvre"], "text": ["Imagine a board with four switches. And each switch has either on or off position. Imagine there's a bulb connected to each switch. So let's say you have the switches in on, on, off, on position. Logically the second to last bulb is off while the rest is on. Now disconnect the board from your circuit. Did the switches go back to some default position? No, because there isn't any. They're still in their last set on/off position. So now you can store the board in your drawer for years and it will still hold the information. *On, on, off, on.* Connect it to the bulbs again and you will see what you saw years ago, Bulbs 1, 2 and 4 are on while the 3rd one is off. So the board was able to hold four bits of information for years without any power source."], "text_urls": [[]], "score": [9]}}, {"q_id": "7vp9cr", "category": "Repost", "title": "What\u2019s inside a computer chip and how does its internals \u2018compute\u2019 things? Essentially what makes the components comprehend the 1 & 0 of the computing lingo to produce/ process a given output?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dtu11am", "dtu0yd3", "dtu1693", "dtu29fs"], "text": ["It's all built from the concept of logic gates. Logic gates are simple statements like: if Input1 and Input2 are both true, then return true Or if either Input1 or Input2 is true, but not both, then return true Or If Input1 is false, then return true (or else false) By stringing those together in lots of complicated and clever ways, you can make the computer do any kind of mathematical logic you like.", "At its most basic they contain transistors, tiny electrical switches operated by electricity. By combining those transistors math and logic can be performed in binary.", "Short answer: It doesn't. Long answer: Abstraction. Computers don't imbue the data they have with any sort of meaning, in the same way that your muscles don't know whether you're lifting a jar of peanut butter or a dumbbell. The microchips are essentially a lot of 'logic gates' (which do things like combine 1's and 0's in specific ways to get new 1's and 0's) that allow programmers to access and modify data in memory (like your hard drive). Eventually programmers got tired of dealing directly with loading and writing data all the time, so they started abstracting away details, giving birth to so-called \"higher level\" languages like C and Java. They're called higher level because they sit on top of levels of abstraction. Instead of saying 'create a label, allocated a bit of memory to store the information linked to this label, and then store the information in that memory address', you just 'make a variable'. tl;dr - People don't like dealing with complicated things, so smart people worked on it until it was simpler for everyone. But still, your computer doesn't 'know' what it's doing. It just works that way because we built it to.", "There are many levels at which you could represent a 1 or a 0, the lowest level is very simple: 1 means there is some electric current present, and a 0 means that there is no electric current present on a circuit. Some basic components in electronics are resistors, capacitors, diodes and transistors. A computer chip is made up of millions of these components arranged in such a way that you can predictably send an electronic signal and have the chip give you a response, for example: If I send the chip 5 volts then it will do nothing, but if I send it anything more than five volts, then it will start returning that voltage intermittently at a regular interval. This can be used to make a light blink or to control the speed at which something happens. A computer chip is basically made up of millions of tiny circuits which you can think of as \"programs\" like these that can be used like puzzle pieces to make even bigger and more complex programs that can do things like hold a value in memory until a condition changes or to do math like add numbers. Once you are able to get a chip to do these very low level types of computations, then you can begin to store 1's and 0's and even group them to create more complicated values like representing the alphabet, for example: A = 01000001 B = 01000010 Now, programmers can come in and start writing software that does even more useful things like listen to input from a keyboard or a mouse and do something with that input, or draw graphics on a screen."], "text_urls": [[], [], [], []], "score": [15, 6, 6, 3]}}, {"q_id": "7vv9eg", "category": "Repost", "title": "why is the C drive named the C drive?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dtvcs0j", "dtvct4o", "dtveago", "dtveabq", "dtvcsh5"], "text": ["The original IBM PC didn't have a hard drive. It had two floppy disk drives, which were A: and B: .When the hard drive came along, it became C: as the next available letter.", "Back in the day, computers usually had two floppy disk drives, designated A: and B:. This allowed you to easily copy files from one diskette to another. So when hard drives came along, they were usually designated C:. By the time floppy drives became obsolete, many program depended on the main hard drive being C:, so it remained that way.", "Because there used to be A: and B: drives too. In the old days before windows PC came with Operating systems like DOS. DOS means \"Disk Operatings System\" and the whole idea of drives was very central to its operations. Early computers had floppy drives and some even had dual floppy drives. The first floppy drive was the A: and the second was the B: if there was one so C: was used for the harddrive so it would be the same letter on any computer no matter wether they had one or two floppy drives. Later windows was pretty much built on top of DOS on simply continued the naming convention. Eventually Optical drives were added and the CD-ROM usually got the letter D: at that point. While fewer and fewer Computers had a B: drive and A: drive. At that point it didn't really matter anymore. Your windows computer has a built in variable called %SystemDrive% that has the value \"C:\" in it. Program nowadays check that variable to find out which drive is used so you in theory could use your normal hdd as A: or Z: or anything in between if you wanted. However there is always the suspicion that somewhere in the last 20 years some programmer has screwed up and simply assumed that your System-Drive is the C-Drive instead of checking the variable. You just know, that some idiot thought to themselves \"It is always C: I don't need to check.\" So in deference to that idiot we continue to assign the drive letter C: even though we could in theory use A: or really any letter. So the answer is tradition and because we try to make things idiot-proof.", "Similarly, the next step was the D: drive, which was commonly used for the cd disk drive or dvd disk drive. Now a days it\u2019s often used for a partitioned hard disk or a second hard disk. E: became commonly used for USB or other exernal drives.", "Because we've started at the beginning of the alphabet. When we were still using (floppy) disks, our PC's had disk drives. Mostly 2, because that made copying from one disk to another easy. These drives were called A and B drive. After that the harddisk came and got the next letter: the C-drive :)"], "text_urls": [[], [], [], [], []], "score": [433, 61, 32, 6, 6]}}, {"q_id": "7w2922", "category": "Repost", "title": "Why do most foods, drinks etc have to be refrigerated AFTER ONE use? What happens to the contents after just one use?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dtwz479", "dtwz3wo", "dtwzevu", "dtxbtaf", "dtwz4hh", "dtwz5fu", "dtxc7gp", "dtxaumu", "dtwza66"], "text": ["In many cases, the contents have been pasteurized. So they're \"clean\" and \"free\" of bacteria sealed as they are. The second you open it, they become exposed to bacteria. Refrigeration slows the growth of bacteria.", "For some products, they are packaged in a environment and method so that the package is sealed, and pathogens are not present. This results in a product with a long shelf life when unopened. Once the package is opened, it is no longer sealed from the environment, and it is possible that bacteria may come in contact and grow rapidly in a warm setting.", "Take an example of a sealed bottle of apple juice. When the juice was bottled, it was sealed and pasteurized. So any harmful bacteria that might have been in the bottle or juice was killed during pasteurization and vacuum sealing prevents any harmful pathogens or oxygen from reaching the product. Once opened, any bacteria that might have been on the bottle lid, or in the air can reach the product inside. Refrigeration keeps the product cold, and slows down the growth of bacteria/yeast. 40 F - 140 F is called the \"danger zone\" in food safety, that's the temp range where bacteria can rapidly grow and multiply. So that bottle of apple juice that you took a sip from has been contaminated with bacteria in your mouth/lips/saliva, and any that settled in from the air. Kept in on the counter, it's basically a giant petri dish with an all you can eat buffet. A fridge should be colder than 40 F, often set to 37F, so out of the danger zone, bacteria can still grow, but slowly.", "How does something so easily googleable get so high on the list but if I posted this it would be 5 trolls telling me to google it or it would be closed because its been asked already...", "Opening it has introduced microbes from the air, your mouth, or hands into the bottle, which will now reproduce and release toxic wastes (food poisoning) into the drink or food. So you have to refrigerate the food or drink to slow them down. The food or drink was pasteurized during packaging which killed the microbes inside, but opening the container recontaminated the food or drink.", "What happens is bacteria, spores, and other contaminants get inside the packaging. Most food producers take great care to have exceptionally clean facilities, and many packaged foods are frozen, pasteurized, or otherwise treated to kill bacteria after the package is sealed. This keeps them fresh, until you open the package. After they're re-exposed to contaminants they need to be refrigerated to inhibit the growth of bacteria/mold/etc.", "TLI5 (try like i'm 5) experiment: Buy some cheap jam. Open it. Lick a spoon and stir the jam a few times with it. Close it and leave it somewhere at roomtemperature for a week. Open it and look at it. You now know why it would have been better kept in the fridge. Others have explained it well enough, but this can easily be made visible with a very cheap experiment.", "You broke the seal and now bacteria and mold got into what was a (relatively) sterile environment. Now you have to refrigerate it to slow the growth of all the nasties you just let in. Hate to sound jaded but is this not something you learn by the time you're 2-3?", "It comes into contact with the air and all the various contaminants that are in it. Within its packaging it has been sterilize or close to it so will not grow bacteria."], "text_urls": [[], [], [], [], [], [], [], [], []], "score": [1801, 220, 93, 26, 15, 15, 7, 5, 4]}}, {"q_id": "7w2ix9", "category": "Repost", "title": "If someone was born slow and skinny, trained for 20 years and became an Olympic sprinter, would their offspring inherit this?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dtx1r5d"], "text": ["If he did not have the genetic potential to be a top level runner he will not get to olympic competition levels as a sprinter no matter how much he trained. So it is not possible for him to have been born slow. Now to the question you were asking. It is possible for life experience to influence how genes activate in your offspring. This is called Epigenetics. Things like bouts of starvation, severe traumas, diseases and disorders can cause your genes to be passed on differently so it is at least theoretically possible for someone who heavily trains their body to have a child that has a greater physical potential than they would otherwise have. But this is still hypothetical. Study of Epigenetics is still in its infancy as a field."], "text_urls": [[]], "score": [7]}}, {"q_id": "7w47au", "category": "Repost", "title": "Why when a country has a king, his wife becomes the queen. But when you have a queen, her husband doesn\u2019t become king but remains a prince?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dtxdf01", "dtxe01r", "dtxe60n", "dtxcfo6"], "text": ["King, by rank, is higher than Queen If a Queen marries, her husband doesn't become a King because he doesn't hold power, she does. Awarding the title of King means he now outranks the Queen This rank is the reason why there's no Queen Jadwiga of Poland, it's *King* Jadwiga of Poland. She took the title King because it's the highest rank in the realm and cements her position, everyone else agreed", "There are two versions of the rank of queen but we generally just call them queen. Queen Consort - queen by marriage, she has no standing in the line of succession. When the king dies it goes to one of his children Queen Regnant - Queen by blood or conquest. She rules by her own right and may have inherited ruling authority from her mother or father There are the same roles for men except King Consort is generally called Prince Consort to indicate that the Queen has full ruling authority and the Prince Consort has no claim to the throne", "Those are two different kinds of queens. Queen-Regnant and Queen-Consort. The first is the one who is monarch because she inherited the title from the previous monarch and the second is just married to the monarch. Both these very different titles get usually just called Queen, but they are not the same. With the male version of those titles it is easier to tell the difference. A King is the ruling monarch. A man just married to the ruling Queen does not get a title like King-Consort or anything like that. He is just Consort to the Queen. Usually royalty marries other royalty and they tend to give out titles to their relatives so the husband of a queen is unlikely to be entirely titleless. Prince Philip was born a Prince of Greece and Denmark and was later made a Duke of England before his wife decided to give him the title of a prince too. None of that however came automatically from marrying the woman who would be Queen. (Philip still outranks his wife though since she may be queen 16 different countries and leader of a religion, Philip is actually worshiped as a God by a small tribe in the pacific.) The discrepancy between the male and female names for these sort of thing mostly come from the fact that men used to be preferred as monarch and thus be more common. Even though over the last two centuries England had had a Queen instead of a King for 130 year 69 years for Elizabeth and 63 for Victoria. So if you take that view having a queen has become more normal than having a King for them at this point.", "Because men always supersede women in patriarchy. A king welcomes his queen because the king would still hold power. If the queen were to marry and make a man become king all of a sudden that king is now ruler. Kings > Queens. Gotta love outdated royalty succession."], "text_urls": [[], [], [], []], "score": [19, 14, 5, 3]}}, {"q_id": "7w6llr", "category": "Repost", "title": "How can the U.S. be trillions and trillions in debt and still function normally? Why at this point would increasing or decreasing it by another trillion even matter?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dtxvmgf", "dtxvpff"], "text": ["It's not the debt that so much matters but how fast we can pay it off. Once we hit a certain percentage on our Gross Debt to GDP ratio, (Somewhere around 110%), Our economy will most likely collapse. Something like Greece's economic collapse but much, much worse. It would affect the entire world since our economy matters a lot more than Greece's. (Sorry Greece.) Hopefully the 4% and growing GDP increase rate will help combat this, and if it continues to grow, we might even be able to reverse some of the debt.", "With a strong payment history, a decent economy, and good responsible control over our own currency, it doesn't matter too much at the moment. The reason it can start to become an issue is because they payments add up. Right now, a lot of our debt is at extremely low interest rates, but when the interest adds up too much, it could turn in to a very significant expense for our government, as it would increase the amount we have to pay to pay back those loans. [Here's a good article that gets in to more detail and is fairly simple.]( URL_0 )"], "text_urls": [[], ["http://time.com/4214269/us-national-debt/"]], "score": [4, 3]}}, {"q_id": "7w6tuc", "category": "Repost", "title": "How do people who are deafblind learn to communicate and learn about the world around them?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dtxxv5b"], "text": ["It's not easy, and it can depend on the individual case. If one sense lasted longer than the other (ie: they went blind when they were a child, but lost their hearing due to a loud noise in their 30s) then they might retain the ability to talk and have some coping mechanisms through touch; similarly if they were deaf, they already know sign language, and just need to learn how to read finger-spelling through their hand (but could, in theory, sign normally in return). One of the most famous deaf and blind people in the world is Helen Keller, and her story was made into a movie called the Miracle Worker; she lost both sight and hearing very young, so she was basically taught sign language through touch; so she could have someone sign onto her hand and she could tell what the letters were."], "text_urls": [[]], "score": [4]}}, {"q_id": "7wc01e", "category": "Repost", "title": "What exactly is a game engine?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dtz5z23", "dtz7s3x", "dtz6ipd", "dtz7lnr", "dtz6wfs"], "text": ["A game requires A LOT of code. Things need to be considered like how will the camera work, how will light be rendered (eg effects like bloom, shadows, as well as just how things will appear or be \"drawn\" in the world), how collisions will work (a foot against the ground, a bullet into a body etc), sound/audio, and heaps more. Lots of this code is reusable, so instead of rewriting all of this for each game, companies will instead design an engine (Source, UE, Unity) which contains all the basic, ubiquitous code found in all of their games and then build each of their games on that. A lot (but not all) of these engines are licensed or sold out to other companies", "A lot of good technical explanations here, so I won't repeat what's already been said. In the spirit of ELI5, I thought I would try to give an analogy. The game engine is a lot like pancake mix. The advantages are clear: you don't have to start from scratch and the quality of each of the ingredients are well known. You are still going to have to at least a little work to make those pancakes. Of course, if you want your pancakes to *really* stand out, you might do quite a bit of work. You might alter the suggested recipe as well, perhaps to make them extra fluffy. Or you might use the mix in some recipe that looks nothing like pancakes, but the mix just saves you a lot of pointless busywork. This is the nature of a game engine. All the common elements come already mixed together, but you are going to have to do the last few steps yourself to make a game. And if you want your game to stand out, you are going to have to do quite a bit of work adding to the engine.", "Pretend you're trying to build something, and you need various shapes. Now pretend you have a toolbox that hold everything you're going to be building with. That toolbox holds everything you're going to be using. Now what you've done, is build a whole bunch of preset items and put it in the toolbox. As you go along, you take the preset items and use it in your build. So basically you create something before hand, and you take the things you have created and put it into your current project so you don't have to keep repeating what you have done before. Its like having a database that you can keep pulling things out from Or maybe pretend that you're building a mario-like game. When you're building, you make various types of blocks that the characters can jump on. And you have it in a way that you can just drag the block into the level and use it while creating the level. It'll be like you being able to keep pulling the premade blocks and putting it in the level you're making", "Computer programs can use \u201clibraries\u201d. A Library is a bunch of common code you can reuse, to save time. You have libraries for math, for making websites, for anything software related. A game engine is a library for making games. It can include common features such as rendering graphics, playing sounds, helping you implement multiplayer, and lots of other things.", "Back in the days when consoles like the NES or SNES were the absolute pinnacle of gaming hardware, games didn't have engines. They were written from top to bottom in code in order to be able to get the most out of the weak hardware available. However, doing this meant that it was very difficult to make complex games, as each time you wanted to change anything about the game, you had to find the corresponding lines of code and change them. And that's where an engine comes in: Instead writing the game entirely in code, you first write a bunch of tools. These are responsible for basic things like the graphics, sound, physics, loading and saving games, ... All this combined is what's called the \"engine\". With an engine, you no longer need to code everything in a language like C++ in order to make the actual game. Instead, it can read out much simpler things like XML documents or LUA scripts, which have the advantage that they are much easier to read and write for humans. For example if you go to the settings menu in a PC game and change the resolution from 720p to 1080p, what usually happens is that it changes an entry in a file called something like \"config.ini\" from \"resolution = 1280\u00d7720\" to \"resolution = 1920x1080\". Now when you restart the game, the game engine reads that file and sets the resolution to whatever it says in there. This is a simple example, but it is how a lot of the things in a game are made: The levels, the quests, the monsters, the items... it's all in a bunch of files that can easily be read, understood and changed by humans."], "text_urls": [[], [], [], [], []], "score": [86, 27, 5, 3, 3]}}, {"q_id": "7wde4y", "category": "Repost", "title": "How does a hard disk drive read and write data differently than a solid state drive?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dtzfm2j", "dtzg7gz"], "text": ["A hard disc drive uses a magnetic metallic plate that spins around and a electromagnetic read/write head. That head can ready the magnetic properties within a very small area on the plate, or change the the magnetic property within said small area. This allows for 2 magnetic states (think of magnetic poles) which can be read and easily translated into the binary states for 0 and 1. Solid state drives instead use a way to essentially trap electrons, which are for the most part either floating-gate-transistors or charge trap flash. You can imagine it as a very tiny cell which traps an an electronic charge. To trap a charge you need much higher voltage than to read it, as you essentially have to force that charge into the cell. And said force is also required to push it out again, while lower voltages allows you to check if there is charged trapped or not. This is also the reason that flash memory degrades over time. Forcing the charge in and out of the cell slowly destroys the ability to hold the charge within the cell. Reading also slightly damages the cell, but not as much as writing to it. I don't think I can ELI5 how the trapping works as the effect used for this is called quantum tunnelling which as the name suggest is a quantum mechanical property.", "SSDs use electrical charges to store data. This eliminates the bottleneck of a HDD head needing to physically move around to access data. I've been awake for 36 hours, so I can't give you a much more detailed explanation, but this is a really great answer to your question. Skip to 54s. URL_0"], "text_urls": [[], ["https://youtu.be/2GvRL5dcinQ"]], "score": [6, 3]}}, {"q_id": "7wdkky", "category": "Repost", "title": "How can different liquors affect someone different, ex, \u201cWhiskey makes him crazy\u201d, are there any actual differences or is it BS?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dtzhg9m", "dtzhii8"], "text": ["It's mostly based on one's personality and the culture around you. URL_0 URL_1 URL_2 URL_3 TLDR: It's all in your head. Alcohol is alcohol. You perception of what it is alters your behavior and reaction to it.", "Different types may hit you faster or slower and thus you'd act differently drinking them but the actual inebriation is identical based on alcohol content. Someone can drink beer slowly all night and maintain a strong buzz and then decide to have a few shots of whiskey that puts them into really drunk territory and they act...well...really drunk."], "text_urls": [["https://www.shape.com/lifestyle/mind-and-body/4-drunk-personality-types-according-science", "http://www.peele.net/lib/personality.html", "http://www.peele.net/lib/sociocul.html", "http://www.sirc.org/publik/drinking4.html"], []], "score": [7, 6]}}, {"q_id": "7wfqjz", "category": "Repost", "title": "Why we say the speed limit in universe is the light speed just because we couldn't observe anything faster than it?", "title_urls": {"url": []}, "selftext": "Why this limit? Why _c_ ? It has been pretty logical to me until I thought why it's not just us can't detect or see or interact something faster than light? The universe is pretty big and expanding every second, there are massive amount of _things_ out there waiting us to observe them. How can we that sure about the speed limit in universe?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["du01hu1", "du006qp", "dtzz0ih", "dtzz62d", "du009iv"], "text": ["The speed limit of the universe is only counter intuitive when you make certain \"obvious\" assumptions about the way the universe works. We see space as a rigid grid. I could take a meter stick anywhere and put it in any orientation and it will always be one meter long. If I have two meter sticks that are exactly the same length as one another then they will always be identical. Similarly we see time as something that marches ever forward at a constant rate. If you and I have synchronized clocks then there's nothing that either of us can do to get the clocks out of sync, short of tampering with then. That view of the universe is very nearly accurate and works for most physics and all day to day activities, but it is actually fundamentally wrong. If you and I both have meter sticks and I start to move then my meter stick will be shorter than yours. As I approach the speed of light the length of my meter stick becomes shorter and shorter, approaching zero. This is not a question of engineering a stronger meter stick or a question of having good enough observation. It is a fundamental property of the universe. It is the nature of space that things in motion are shorter along their direction of motion. Similarly if we both have clocks and I start moving around then my clock will run slow. The nature of movement is that everything in the universe has some amount of total movement (and I'm speaking in coarse language here; I'll abuse some terms for the sake of ELI5). When an object is at rest its movement is entirely through time. As it starts to move it trades some movement through time for some movement through space, but the total is still the same. What makes this foreign to you and me is that the conversion ratio is *enormous* (it is the speed of light, 300 million meters to one second). The analogy would be to Bill Gates buying a burrito at Chipotle. One may see a multi-billionaire with no burrito walk into the restaurant, then a multi-billionaire with a burrito walk out of the restaurant. Another day you see the same, but he walks out with a box of 100 burritos to throw a burrito party for a group of people. Someone watching Bill Gates may posit that there is no burrito limit of the universe. Gates was a multi billionaire before and after each transaction, even with differing numbers of burritos. Clearly there is a limit, though. There is some finite, albeit enormous, quantity of burritos that Gates can afford. When you find the conversion ratio between Dollars and burritos the burrito limit is trivial to compute. That is what we've done to determine that the speed of light is the speed limit of the universe. We discovered that motion through space \"costs\" motion through time, then we found what the conversion rate is.", "\"Light speed\" is a bad name. It's actually the speed of causality, which means that it is the fastest possible speed at which anything can affect any other thing in another place in the universe. It just so happens that any massless particle (like photons of light, for instance) travel at that speed. But I haven't answered the question, really. Could there be things that go faster than light? There have been a number of hypotheses about these types of things, some of which are plausible at least to some extent. The problem is that these exotic types of particles would have very bizarre properties: imaginary mass, experiencing time the reverse of how we do, etc. They also would have to violate causality. That is to say, it would break our understanding of cause-and-effect. So not only would they be hard to find, but it throws some tricky wrenches into physics as we understand it. EDIT: Let me sum this up, I'm not happy with how I left it. The long and short of it is, yes there could be faster than light stuff out there. Judging by what we have found and how much physics we know, it seems that they are either unlikely to exist, or they don't interact with normal particles in any way of serious consequence.", "> How can we that sure about the speed limit in universe? Because we have not seen anything that breaks that rule yet. If we do, science will incorporate that into the existing theories. This is a reason why the recent observation of gravitational waves was important. We knew that a cosmic event was going to happen (I don't remember, was it a supernova? Binary star collision?), and the gravitational effect occurred at the speed of light. We expected it to do that, and it did.", "We make observations about the universe. We construct a theory, usually involving mathematical equations, that explain those observations. We make more observations and see how they fit with the theory. For light, we observe that the speed of light is the same regardless of your frame of reference (Maxwell's equations). From this we (as in Einstein) deduced the relativity of time and the fact that nothing can go faster than the speed of light. Our observations of the universe at a large scale are consistent with the mathematical equations whose consequence is that you cannot go faster than the speed of light. It's important to note that there is nothing special about light here. Rather anything that is massless *must* always be travelling as fast as it is possible to travel. Since light is massless, it travels at this maximum speed. We call it the \"speed of light\" simply because the photon is the most common massless particle that we deal with and it is our observations of light that led us to this discovery.", "It's the only way of making sense of the universe as we observe it. It all began with an experiment to detect the presence of something called \"ether\". At the time people weren't sure what light actually was; one theory was that light is waves in this mysterious thing called ether, like waves in water. If that's true, then there should be a detectable \"drag\" slowing light down slightly as it travels through the ether. So some scientists set about trying to measure this drag. How do you do that? Simple: you measure the speed of sunlight in the morning, when the bit of earth you're standing on is rotating towards the sun; and again in the evening, when you are rotating away from it. You should be able to detect a difference in the measured speed of the sunlight. You then calculate how much of the difference is down to the earth's rotation: if that doesn't exactly account for the difference, then that means ether exists and is slowing down the light. The problem was that the results of the experiment made no sense: the measured speed of light was always *exactly the same*. Understanding the results took the genius of Einstein to look at these results and work done by other scientists, and finally figure it out: the speed *c* is the maximum speed any two objects can move relative to each other, and light (at least in a vacuum) always moves at *c* relative to everything else. This is hard to grasp because it goes against our intuitive understanding of how the universe works in our everyday experience, but there it is: if *c* is the universal speed limit, that would explain the weird results of that experiment. Einstein's theories made some predictions -- that light should be affected by gravity, and that accelerating to very high speeds results in something called \"time dilation\". Since then, scientists have done experiments and confirmed that light is affected by gravity, and that time dilation is a thing. Not only that, but your GPS is able to pinpoint your position exactly thanks to Einstein's equations, based on the idea that *c* is the universal speed limit. On balance, then, it seems that Einstein was right. As weird as it sounds, there is no such speed as \"faster than the speed of light\": all the evidence says that that speed simply does not exist."], "text_urls": [[], [], [], [], []], "score": [11, 10, 8, 3, 3]}}, {"q_id": "7wg6vq", "category": "Repost", "title": "why/how do we get more courage and self-confidence when we drink alcohol?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["du049vc"], "text": ["Alcohol serves to dull our inhibitions, which would otherwise caution us in the form of fear."], "text_urls": [[]], "score": [3]}}, {"q_id": "7wid08", "category": "Repost", "title": "How do construction companies get cranes on top of sky scrapers that are hundreds of stories high?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["du0mg8d", "du0lzck", "du0krzf", "du0kozz"], "text": ["Idk if I'll get deleted for linking this but I shot a lil time lapse for when these questions get asked. Note the weight hanging in the front for balance as well as the hydraulic ram on the backside of the tower, where the workers are moving. What u see them roll out is 20 foot tower section. So the crane grows and shrinks 20 feet at a time. URL_0", "Here's a good video that should answer your question: URL_0", "The base of a tower crane is a concrete slab that is fixed to the ground (it can be attached to the sides of the buildings/structures as well). The base connects to the tower which is what gives the crane its height. At the top of the tower is a slewing unit which allows the crane to rotate using its gear and motor. Now you know the basics, the answer to the question is really surprisingly simple. The crane builds itself up, level by level, using its own hoisting power. Let me break it down a little more\u2026 To assemble to a tower crane initially, construction crew will use a (smaller) mobile crane to assemble the jib and machinery. The tower rises from the base, and grows itself one section at a time. A top climber or a climbing frame is used for this process. It fits between the top of the tower and the slewing unit. Explained simply: 1. A weight in hung from the jib to balance the counterweight 2. Slewing unit is detached from the top of the mast. 3. Hydraulic machine in top climber pushes the slewing unit up 4. Crane is lifted up (by the crane into) another mast section into the gap that has been opened up by the climbing frame. 5. Once lifted it is bolted into place and a whole tower section taller", "It\u2019s deconstructed, moved to the top by construction elevator/pulley system and reconstructed at the top"], "text_urls": [["https://instagram.com/p/z3jWuqMNug/"], ["https://www.youtube.com/watch?v=RB91Sm-kGJ8"], [], []], "score": [12, 6, 4, 3]}}, {"q_id": "7wj3eh", "category": "Repost", "title": "Why did Korea split into North and South?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["du0r84c", "du0rqq7"], "text": ["At the end of ww2 Korea was occupied by the Japanese then spit by the victorious allies with the communist north and the US backed south.", "Prior to WWII, Japan occupied Korea. Near the end of the war, the Soviet Union declared war on Japan, as per their agreement with the other allied nations. They attacked the Japanese in northern China and continued into Korea. When the Japanese surrendered, the parts of Korea invaded by the Soviet Union were administered by the Soviet Union, and the parts that remained under Japanese control when they surrendered to the USA was administered by the USA. The USA and the Soviet Union negotiated for a unified Korea, but they could not come to an agreement. In 1948, and without a resolution between them, South Korea and North Korea both officially became separate independent countries, although they both claimed to be in charge of all of Korea."], "text_urls": [[], []], "score": [7, 4]}}, {"q_id": "7wmr8y", "category": "Repost", "title": "How do guitar amps amplify the sound?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["du1kho3"], "text": ["A transistor! To answer the follow-up question of \"okay and what the hell is a transistor\".... A transistor is a lil' electronics part made of silicon. Silicon has some funny properties: it's a semiconductor, and different stuff can influence how well it carries electricity. So a transistor has 3 connections on it: an in, an out, and a signal, positioned in-between the two. A strong current goes into the \"in\", but nothing comes out until any current (even a trickle) goes to the signal connection. So what they do is hook the \"out\" to the amp's speaker. Then when you strum the guitar string, that's connected to the \"signal\" and causes the signal current to wobble. This means the \"out\" juice starts to flow, and wobbles in the same way.... but much stronger, since the \"in\" was a strong current. This makes the speaker vibrate in the same pattern your guitar string did."], "text_urls": [[]], "score": [4]}}, {"q_id": "7wnpo2", "category": "Repost", "title": "Why do some many animals immediately know how to walk after birth, yet it takes human babies months just to learn how to crawl?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["du1qtsk"], "text": ["Humans have large heads to control our large brains. Unfortunately, human female pelvis's are basically too small to pass fully developed large heads. So basically all humans are born premature (by animal standards) in order to let our mothers fit our massive heads through their pelvis. Then we continue to develop after being born and can't walk for months."], "text_urls": [[]], "score": [11]}}, {"q_id": "7wnpqa", "category": "Repost", "title": "How does the temperature gauge that reads the outside temperate that is displayed inside your car not get thrown off by wind/other elements when you\u2019re traveling fast down a highway?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["du1qne9", "du1qoj7", "du26fnz"], "text": ["Wind doesn't actually change the temperature. Wind feels colder to you because your body is 98.6 degrees, so on a cool day with no wind, there is a layer of warm air (warmed by your body) surrounding you... but on a windy day, that warm air gets blown away, so you feel cooler. A thermometer doesn't have a layer of warm air around it, so it just feels the temperature, regardless of wind.", "The wind doesn't make a thermometer any cooler. It makes warm-blooded mammals like us cooler because, unlike a thermometer, we're not at equilibrium with our surrounding environment. Instead, we heat the air around us, and wind blows that pocket of warmer air away, causing us to lose heat faster. And since we feel heat loss/gain, and not actual temperature, blowing away that warm air makes us feel cooler.", "ELI5 version: Your car's gauges lie to you all the time. They are made to be close enough to be useful without wiggling all about and being distracting or annoying. Cracked has a decent articles about it: URL_0"], "text_urls": [[], [], ["http://www.cracked.com/article_19571_8-gadgets-that-lie-to-you-every-day.html"]], "score": [126, 19, 3]}}, {"q_id": "7wqxc7", "category": "Repost", "title": "What causes your limbs to \"fall asleep\"", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["du2jqes", "du2jp8x"], "text": ["The idea that it's circulation is actually a myth; when limbs lose blood flow, they don't \"fall asleep\", they die. A limb falling asleep is caused by pinching the major nerve leading to that limb. Signals can't travel up the nerve very well, so feeling becomes limited. When the limb \"wakes up\", you feel pins and needles because there's a huge backlog of signals in the nerve being cleared and your brain is trying to make sense of it all.", "When your limbs \"fall asleep\" it's called paresthesia. It's caused by either accidently pinching/putting pressure on a nerve or by decreased blood flow to the area. It doesn't typically cause nerve damage due to the short duration that it happens, usually. It also usually goes away if you adjust or move the limb around. When the sensation persists or happens frequently it can cause complications, and is usually associated with another medical issue. That would be the time to consult a doctor."], "text_urls": [[], []], "score": [7, 4]}}, {"q_id": "7wuzv2", "category": "Repost", "title": "What actually happens when your legs fall asleep and why does it hurt so much to walk when they do?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["du3depm", "du3dh4x"], "text": ["You've put pressure on a nerve, most likely. This interrupts the normal ability of that nerve to send signals to be interpreted by your brain. So in a sense your brain is 'blind' to this area. Once you remove the pressure, the nerve can begin to send signals again, but the pressure and the stoppage have resulted in abnormal signaling. It's this abnormal signaling that takes a little bit to clear, and which results in the weird sensations like pins and needles.", "Brain (mom) stops getting messages from nerves (you). You finally come home and Mom hasn't heard from you and it's midnight, so she grabs her switch and starts chasing after you around the dinner table and then whoops your butt."], "text_urls": [[], []], "score": [7, 6]}}, {"q_id": "7wv0kn", "category": "Repost", "title": "How does moving water freeze?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["du3drby", "du3est6"], "text": ["Moving water freezes just like non-moving water does. First, imagine floating in a still pond that's beginning to freeze. Bits of water around you will start turning into small pieces of floating ice. The ice will grow and grow until it covers the surface of the pond. Now imagine floating in a moving stream. Bits of water around you will start turning into small pieces of floating ice, just the same as before. From your perspective as someone floating along with them, it looks identical to ice forming on a still pond. The only difference is that the whole process is moving downstream as it happens.", "Okay...Rivers never actually freeze solid. Not that I can find an example of... Ice is a good insulator and poor conductor of heat, so the exposed part of the rivers will freeze over, but it slows down exponentially the thicker it gets as the ice actually acts as an insulator to the cold outside... So the kinetic energy of the moving water flowing and rubbing against each other plus the nice cozy layer of insulating ice above it kinda warms the water at the bottom of rivers enough to keep it from freezing throughout. I'm sure the pressure makes a difference as the weight of the ice pushes down on it, and pressure changes the freezing point even lower... but i'm not too sure so... Also fun fact: the fact that ice floats on top of water instead of sinking is actually really weird... chemically speaking. If it sank to the bottom, THEN rivers would freeze solid. And in a world where ice sank there would be no life, at least not complex life. since the oceans would have frozen solid during the worst of the ice-ages as it slowly froze from the bottom to the top, nothing but microbes could live is solid ice. [in theory. i'm no expert] I'm open to anyone correcting me and improving the explanation. It's my first ELI5 comment. sorry"], "text_urls": [[], []], "score": [257, 17]}}, {"q_id": "7wv2cv", "category": "Repost", "title": "Hypnosis/being hypnotized", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["du3e4rw"], "text": ["Hypnosis is a very controversial subject. Please take any answers/articles/links with a grain of salt, and beware of the pseudo science/superstitions going around on the internet."], "text_urls": [[]], "score": [3]}}, {"q_id": "7x0oqt", "category": "Repost", "title": "How do pain relievers relieve pain?", "title_urls": {"url": []}, "selftext": "I\u2019m currently sick and just took some ibuprofen and wondered how it helps.", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["du4lb9d"], "text": ["Ibprofen isn't a pain reliever per say, it is an anti-inflammatory. What is does is reduce swelling, so it may be reducing the swelling in your throat or nose so you may feel less pain. Other medications that are pain relievers block pain receptors like the user above explained."], "text_urls": [[]], "score": [3]}}, {"q_id": "7x1ddm", "category": "Repost", "title": "Why does light always travel at c (in a vacuum), no matter what the speed is relative to?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["du4omzb"], "text": ["There isn't a satisfying answer to this. It simply *is*. We observe that this is the case, so the \"why\" is that it does. All of our theories about the universe and how it works (and why things do things the way they do things) all *rely* on the fact that light travels at the same speed to all observers."], "text_urls": [[]], "score": [7]}}, {"q_id": "7x87di", "category": "Repost", "title": "If our own average core temperature is 37\u00b0c, then why do feel hot in same outside temperature?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["du68px7"], "text": ["What you feel is not temperature, but the exchange of thermal energy. Consider the following: a paper book and a piece of metal are lying in a cool room. After some time, you go in and touch them both. Even though both have the same temperature (since they have been in the same room for some time), the metal object will *feel* cooler than the paper book. The reason for this is, that metal is a better thermal conductor than paper. Since your fingers are hotter than both the book and the piece of metal, both will transport energy away from your fingers upon contact. The piece of metal, however, will do this much more efficiently and faster than the paper. Thus, you are losing way more energy to the metal than to the book, which is why it feels colder. Being aware of this, we can answer your question: Our bodies are used to losing a certain amount of thermal energy to our surroundings. We feel comfortable losing a rate of thermal energy that corresponds to being in a ~20-25\u00b0C environment. If our surrounding environment is the same as our body temperature, we will not be able to lose thermal energy to the air. Thus, the flow of thermal energy from our bodies to the environment will be smaller than our bodies are comfortable with, thus making us feel hot."], "text_urls": [[]], "score": [3]}}, {"q_id": "7xgoun", "category": "Repost", "title": "Why A Glass Of Water Left Overnight Develops Bubbles?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["du85qdb"], "text": ["Gases can dissolve into liquids. The amount of gas that can dissolve into a liquid is dependent upon the temperature of the liquid, and the pressure of the gas at the interface (the boundary between the liquid and the gas). In this case, the pressure is the atmospheric pressure in your locality. When you fill a glass with water from the tap, there will be an amount of gases dissolved in it (mainly nitrogen and oxygen, as these are the most abundant in our atmosphere). Typically the temperature of the water from the tap will be considerably lower than the room temperature. As the water temperature increases to the room temperature, the amount of gases that can remain dissolved decreases. Microbubbles of gases will begin to form. They will collect on imperfections in the surface of the glass. (The glass looks and feels smooth to us, but at the microscopic scale it is not.) As they collect on the imperfections they will coalesce (fancy word for them joining together to make bigger bubbles). Eventually they will get big enough to be visible. This effect is similar to bubbles coming out of a fizzy drink, but in the case of a fizzy drink it is a sudden reduction in pressure (taking the cap off the bottle) that causes the dissolved gas (carbon dioxide) to come out of the liquid."], "text_urls": [[]], "score": [8]}}, {"q_id": "7xim6x", "category": "Repost", "title": "\u2013 what are the causes of sudden nose bleed?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["du8icis"], "text": ["The main culprit is usually dry air. Dry air causes your nasal membranes to crust up pretty much in the same way skin gets dry too. The nasal membranes can crack when they're dry through some movement in the nose or even randomly, which causes the bleeding."], "text_urls": [[]], "score": [3]}}, {"q_id": "7xizaf", "category": "Repost", "title": "Game theory. And what are some real life examples of putting it to use ?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["du8lu88"], "text": ["Any time you've held off on buying something because you know it's on sale elsewhere (or that it will be on sale next week), that's game theory right there. Just as one example."], "text_urls": [[]], "score": [4]}}, {"q_id": "7xoob0", "category": "Repost", "title": "Bandwidth for internet vs. tv", "title_urls": {"url": []}, "selftext": "Thanks in advance for the ELI5! ISP's always say you need faster speeds for downloading, gaming, etc. What confuses me is that I can watch TV on as many TV's as I want (which is delivered via the same cable to the house) and not have it degrade service at all. But, somehow that same configuration with streaming will slow down the service (for example, streaming a movie, playing a game, etc.) if I do it on multiple devices. Since the service is piped through the same wire, how is it that speed matters for one service but not another. Isn't the TV service, technically, streaming? I am guessing not, but didn't understand why it would matter. Thanks!", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["du9ybkz", "duakuk4", "du9y6lg"], "text": ["The difference is cable is a broadcast. It's just the same information down the same wires at the same time, you're just reading it in multiple locations, you're not streaming. Streaming is an on-demand service, which is different. Each device you use for streaming requests its own lump of data to be sent. Even if you and six other people in your house go to Youtube and hit Play on the same video at the same time, it's still sending that information down the wires six separate times. So with streaming the more you ask of it, the more bandwidth it uses.", "While others have stated that TV is broadcast to every TV using the same signal, and the Internet is sent to each device individually. I thought I can expand a bit on how it works. Your cable wire is basically just the same thing as radio waves, but they are all stuck in the cable instead of going through the air. and just like the with the radio where you can have stations broadcasting on 101.3FM and 105.7FM and they do not interfere with each other, there can be more than one station (which in the Cable TV world is a channel) working at a time. Cable TV (In North America) channels are all divided into blocks of 6MHz each. So channel 40 is centered at 321MHz, and Channel 41 is centered at 327MHz. We call these EIA channels (For the Electronic Industry Association, which wrote the standard) and are different from what most people today think of as a TV channel. Your cable box may have a 'TV Channel' 312 that then has a map inside of it that says if I want to look at channel 312, it can be found on EIA channel 29, program 3 and then displays that. Each one of these 6MHz block can contain one of a few things. * 1 single Analog SD TV channel, with stereo audio * A group of Digital TV channels (Usually 2-5HD stations, or as many as 15SD) * A Internet channel (DOCSIS) which can run 38Mbps of Internet. There is a limit to how many of these channels will 'fit' on the cable. Most modern cable systems can fit 116 (750MHz) or 158 (1GHz). Every house on a cable node gets the exact same signal sent to it. With TV, as it has been pointed out, every TV gets the same copy of a station so it does not take extra bandwidth to add more TV's. But with Internet, every device (not just in your house, but in every house on the node which can be up to 100 or so) gets its own copy of the data. But since every house gets the exact same signal, every house is getting a copy of everyone's data, and those DOCSIS channels quickly can fill up. Just as a point, in modern cable systems, internet data is encrypted between the Cable company and a modem, and only your modem can decrypt the data that is intended for you. So while every house on your node gets a copy of your data, only your modem can actually do anything with it.", "I believe when you get a cable package, all the cable channels that you have are always sent to you. So when you use the TV, you get the same channels and \"streams\" as everyone else, always; the TV is just choosing which of the streams that you're sent to look at. You can hook up as many TVs to this cable as you want, and it won't affect the speed you get the data at at all, because the data has already been sent; you aren't asking for anything new. When you're streaming, you are asking for an individual stream, which requires bandwidth. You don't get all of Netflix by default; you have to pick out an individual show, and then download that show from Netflix's servers somewhere. In turn, downloading multiple shows takes a longer time because you're receiving twice as much data. Basically, it's a lot easier and faster to send everyone the same thing than it is to send a bunch of people a bunch of different things. I am not sure this is accurate at all, though, so I'd appreciate someone to verify."], "text_urls": [[], [], []], "score": [9, 4, 3]}}, {"q_id": "7xpf01", "category": "Repost", "title": "How do EMPs actually work? I know WHAT they do, I just don\u2019t know HOW they do it.", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dua3iio", "dua3l7b"], "text": ["Electromagnetism. Electricity moving through a wire can create a magnetic field, and a moving magnetic field can create electricity in metal objects. When a big EMP happens it creates big electric flows in electronics - bigger than they are designed to take. This can damage all the delicate things inside your phones and things.", "Electromagnetic pulse. Basically, you know the basic principle of radio transmission. Voice goes in one end, it's converted to radio frequency and that signal is pumped into an antenna. That then travels as radio waves, and is picked up by an antenna at your end, and is turned via electronics back into sound. In the most basic electrical sense, an electrical signal in a wire is creating an electromagnetic signal which causes an electrical signal to be induced in a wire (or antenna) at your end. EMP is just that principle, just stepped up to crazy power levels, so the resulting electromagnetic signal is powerful enough that the electrical signal it induces is enough to burn out various electronic systems, because every wire will act as an antenna to some degree. EMP takes advantage of that to cause intentional damage."], "text_urls": [[], []], "score": [6, 3]}}, {"q_id": "7xq07l", "category": "Repost", "title": "Meteors and debris burn up in our atmosphere upon entry, why are rockets not affected in the same way when leaving the planet?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dua6tcl", "dua84j7", "dua825r", "dua82wk", "dua8k4g"], "text": ["They don't move fast enough in the athmosphere to burn. They do accelerate to a significant speed but are already pretty much in space when they finally do go that fast.", "Rockets start slow and go fast once they leave the atmosphere and all that wind resistance. Meteors start really fast and then get slowed down by the atmosphere with all it's wind resistance. That wind resistance causes heat that burns them up.", "The heating is caused by compression of gas. You probably know that if you compress gas it heats up. Objects entering our atmosphere from space tend to do so at tremendous velocities, so they hit the air hard, and squash a lot of it in front of them. This air gets very hot and in turn heats up the object. Even stuff in orbit tends to be moving *very* fast (otherwise it would crash into the ground), and this means when it hits the air, it smashes a lot of air into a small space, and that air becomes very hot and heats the object. A space ship is designed, as others have noted, aerodynamically, so that less air gets squashed in front of it. Additionally, they generally take the shortest route possible through the majority of the atmosphere, so there is less time spent with a significant volume of air in front of them to squash, and during that time they are coming from a stop, so their speed is lower than a reentering body. Once a ship is in orbit it doesn't come to a stop with respect to the atmosphere, but in fact must accelerate to a significant velocity in order to \"stay up.\" Otherwise it would simply fall back to the ground. Next time it hits the atmosphere, it will be with a significant portion of that tremendous speed.", "The atmosphere is thickest towards the bottom. Meteors get faster as they fall, whereas rockets speed up as they climb. So the meteor is fastest when the atmosphere is thickest, but rockets are fastest when the atmosphere is thinnest.", "A number of factors: Speed of leaving the atmosphere is much lower than a meteor which can reach speeds of almost 300,000 kph, compare that to a rocket, around 30,000 kph, so the forces tearing at the spaceship are much lower. Space shuttles have material very resistant to heat damage on different parts of the space craft, like silica tiles (basically a quartz composite). Some crafts even have a plastic coating that melts away pulling the heat energy away from the craft. There is also a layer of insulation under the outer layer to protect the inside. Upon reentry, things get a little more complicated. Shuttles have to come in at the perfect angle (around 40\u02da) too flat and they can bounce off the atmosphere back into space, too sharp and they risk burning up."], "text_urls": [[], [], [], [], []], "score": [169, 55, 24, 7, 4]}}, {"q_id": "7xqcj0", "category": "Repost", "title": "Soaps and conditioner", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dua9l5k", "duaey24"], "text": ["Basic soap is a fatty acid and an alkali mixed together, like animal fat and lye. The fat and the lye bond together. The fat hates water but loves just about everything else. The lye loves water and will attach to it. So, the dirt/grease on your skin or clothes sticks to the fat and the lye attaches to the water so that it all floats away. Dunno about conditioner, other than it's fat-rich and intended to put back some of the healthy hair oils that the soap stripped away.", "In terms of germs since you mentioned you are a germaphobe: soap works to disrupt and destroy the cell membrane, or the walls of the cell . As mentioned earlier, since it is both fat and water-liking, it can work it\u2019s way into the cell membrane and mess it all up. Another fun fact: When they recommend washing your hands with hot water, it\u2019s not because the hot temperature\u201ckills\u201d the bacteria. It is because the hot water tells the bacteria it is \u201csafe\u201d so they can start reproducing. The cell membrane is the weakest and thinnest during replication since it stretches, so the soap works even better. TL:DR Soap damages bacteria membranes and hot water helps the soap work better."], "text_urls": [[], []], "score": [38, 10]}}, {"q_id": "7xs9ct", "category": "Repost", "title": "Why do most car wheels have five spokes?", "title_urls": {"url": []}, "selftext": "There are 360 degrees in a circle, which is the shape a wheel is in. 360 can be divided equally by every number (except seven) from one to ten. Obviously a one or two spoke wheel doesn\u2019t make much sense, but four through ten seems to be viable options. Why do the vast majority of car wheels have five spokes?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["duatsgd", "duau3ig"], "text": ["Four is not nearly as strong as 5 because the separation is too even. 5 is the least number that can be very-very strong.", "I think it's a combination of minimal material and stability. With 5, if you lose one you still have at least one other leg supporting in the same half. Also, no spoke is directly across from another."], "text_urls": [[], []], "score": [5, 4]}}, {"q_id": "7xsqh3", "category": "Repost", "title": "Why can spoiled food still make us sick even after its been thoroughly cooked?", "title_urls": {"url": []}, "selftext": "Typing this while I'm home sick with food poisoning.. If spoiled food is cooked long and hot enough to kill bacteria, why can it still make us sick? Can dead bacteria still cause issues? Or is it something else? (If anyone is curious, I ate week-old chicken curry that had been in fridge, and I boiled it for a solid 15 minutes to kill any bacteria. Still got sick. How?) Edit: I didn't intend for this to be a repost, but apparently it is! Thanks for answering anyway, both informative and terrifying.", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["duatkyo", "duauv4i", "duaytrz"], "text": ["In this case it's not the bacteria that make you sick, at least not as much as if the food hadn't already been cooked. It's the toxic substances produced ~~after the bacteria died~~ by the bacteria. Boiling will kill pretty much any bug that gets you sick, but it won't get rid of nasty stuff that happens after that.", "There are many possibilities depending on what a person is infected by. The first and probably most common would be toxins released by an organism during it's life cycle. One classic example would be botulism toxin (BTX), which is produced by the bacteria Clostridium botulinum. BTX inhibits the release of the nurotransmiter acetylcholine which is a key part of muscle contractions. Because BTX is only a biproduct of the bacterium and not the actual organism, just killing the bacteria won't get rid of the toxin they have already produced. Another possibility for infection is by parasites. While cooking food will kill most parasites there are many that are capable of encystating and forming an incredibly resilient protective barrier until they receive signals from their environment that tells them that reproduction or growth is favorable.", "The last time I saw this come up in ELI5 someone said, think of it like an old west town, Bandits poisoned the water hole. If you lock the bandits up, the water hole is still poisoned."], "text_urls": [[], [], []], "score": [14, 8, 6]}}, {"q_id": "7xuou0", "category": "Repost", "title": "How does a road just have a big missing chunk? How does a pothole even happen?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dubakwx"], "text": ["It can start with a crack and move it's way up from there. Most roads are either concrete or asphalt, so multiple things can cause damage. Constant wear and tear of multi-ton vehicles driving over it. Variable temperatures causing expansion of a limited space. The big one would be water, which can cause erosion, or worse, freezing in various cracks. Because water expands when it freezes, it can make small cracks bigger, break off pieces of the road until you get a pothole."], "text_urls": [[]], "score": [4]}}, {"q_id": "7xvi1p", "category": "Repost", "title": "Film restoration: How is it possible that old lo-res films can be \"restored\" to HD or even 4k resolution?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dubhlg7", "dubi1xg"], "text": ["If the film is actual film then it doesn\u2019t really have a resolution except what you scan it at. So you scan it at a higher resolution to digitize it. Then you fix any bad parts and/or run some filters to make it more modern.", "Films are a series of pictures on a reel of film. That film has far higher resolution that we can actually scan. Each tiny cluster of chemical colorant molecules, the smallest unit in film, can store image data for a very long time. As long as film is not damaged, we can go back and scan it any time new scanning technology becomes available. As computer software gets better we can even correct for damage to the film and the colors that didn't record very well on film. Sometimes film needs to be fixed. If it was scratched, torn or cut some special mending needs to happen. A lot of that can be done by spicing in other pictures of the same thing, or redrawing the flawed parts of the image. Most of this is done on computers too."], "text_urls": [[], []], "score": [10, 5]}}, {"q_id": "7xybb9", "category": "Repost", "title": "Can someone please explain what stops glue from sticking inside the tub or tube?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["duc34nu", "duc6hny"], "text": ["Most glues work on that they need oxygen to become sticky/harden. Inside the tube there is no air and thus the glue doesn\u2019t harden. Some other specialized kind of glues mix 2 components with the use of 2 nozzles/tubes (epoxy etc) thus making them react into the sticky glue substance.", "Most adhesives need some other components to activate. This can be air, heat, pressure, water, or another specially-made compound. For example: Super-glue (often cyanoacrylate) requires water to harden, which is usually absorbed from the air."], "text_urls": [[], []], "score": [14, 3]}}, {"q_id": "7xyc20", "category": "Repost", "title": "Why can so many medical things be done in labs and on mice but we never hear of it ever again?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["duc3cf5"], "text": ["Let me tell you a secret, passed down from generations of scientists, and now I bestow this sacred knowledge onto you: **People. Are. Not. Mice.** While we do share a fair amount of genes with mice, we are too different to reliably predict the outcome of a medicine on humans by observing what happens to the mice. Monkeys and pigs would be far better test subjects, unfortunately they're much more expensive than mice, and testing on them is ethically less correct. So mice serve mostly as a first barrier for medicines: if it doesn't work on them, don't bother trying it on humans."], "text_urls": [[]], "score": [3]}}, {"q_id": "7xysiu", "category": "Repost", "title": "How does Netflix make money?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["duc6yd9", "duc6sv3"], "text": ["> How does Netflix make money? They charge people for their service. > It can't be just from subscriptions can it? Yes it can. > Aren't they in debt? No. They pulled in over $11B in revenue last quarter.", "They have over 100 million subscribers. At approximately $10 per subscribers, they bring a revenue of over $1 billion *per month*. I'd say that's more than enough to make a profit."], "text_urls": [[], []], "score": [11, 6]}}, {"q_id": "7xythm", "category": "Repost", "title": "The Monty Hall Problem", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["duc7aau"], "text": ["You have three doors. Behind one - randomly - is a car. Behind the other two are goats. You only have a 1 in 3 chance of picking the car. So, whatever door you pick, it has a 1 in 3 chance of being a car and a 2 in 3 chance of being a goat. Odds are, you picked incorrectly and the car is behind one of the other two doors. It's in your best interest to pick a different door, but you don't have any information to make a better choice than a random pick meaning you can't - without additional information - increase your odds better than 1 in 3. Monty gives you that information. He removes a bad door from the remaining set. Remember, when you originally picked your door, there was a 2 in 3 chance you were wrong and it would be better for you to pick a different door but you had no way of picking a better door because you didn't know anything about the other two doors and would just have to pick randomly. With the information Monty gives you, you don't pick randomly anymore. He removes a known bad door allowing you to switch off the (likely) bad door you picked initially. This is simple enough to map out. In each case you have picked the first door. Scenario A: [Goat][Goat][Car] Scenario B: [Goat][Car][Goat] Scenario C: [Car][Goat][Goat] Only in scenario C do you want to stay with your original pick (the first door). But there is only a 1 in 3 chance you are in that scenario. If you are in scenario A or B, you want to swap doors because you are guaranteed to get the car in that case (Your original door was a goat and Monty removed the remaining goat)."], "text_urls": [[]], "score": [10]}}, {"q_id": "7y1cba", "category": "Repost", "title": "how nielsen tv ratings work", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ductbcx"], "text": ["They used to give viewers/households a \"diary\", in which they'd describe their viewing habits and submit after some period of time. Now, they have electronic meters, little boxes that actually monitor what you watch, when you change the channel, etc., and sends that data off each night. The first of these used a phone line to send the data back... I'm really not sure if they just connect to the internet nowadays."], "text_urls": [[]], "score": [3]}}, {"q_id": "7y1fxm", "category": "Repost", "title": "How do \u201cthey\u201d determine how many calories are in something?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ducu3s5", "ducwri1", "ducxyn4", "ducylup", "dud05tc", "ducu23i", "ducz3nx", "duczakn"], "text": ["The old-school way was to actually burn it and see how much heat it produced: a calorie is an actual measure of energy. Nowadays, the food would be blended up and analyzed for the amounts of fat, protein, carbohydrate and alcohol (the stuff you can get energy/calories from), and knowing the amount of calories in each of those by weight, they just calculate how many calories it should have. The advantage here is that they can differentiate between calories your body will use, and calories it won't (like that in fiber: it'll burn, but our bodies don't digest it).", "There are also tools available that measure calories. That's not necessarily how \"they\" determine how many calories are in a packaged or menu item, but it's one way they can get a value on how many calories some foods have. URL_0", "To add to the comments about methods: A calorie and a Calorie (food) are not the same. 1 calorie is the amount of energy it takes to raise 1 gram of water by 1 degree celsius at 1 atmosphere of pressure (isn't metric great??). 1 Calorie (big C) is the measurement used in food, and is actually 1000 calories, or 1 kilocalorie, or 1 kcal. Not directly relevant to your question, but still useful to know.", "It's easily estimated by measuring the carbohydrate, protein, and fat contents. Each gram of carbohydrates and protein contains approximately 4 Calories (kilocalories). Each gram of fat contains approximately 9 Calories. You can check the math since the nutrition facts should also include the contents of each of these.", "Woah I have the real question here. If they determine calories by setting food on fire and measuring the heat it produces, can you apply that to anything you could set on fire? Like could you find out the calories of a chair?", "In chemistry, you take a certain amount of the material and burn it inside of a cup that is inside of a larger cup of water. Then you measure how much hotter the water became after you burned it. But for humans it is much more complicated. Variables include - how digestible it is and how it effects your desire to eat more in the future", "I don't know if this is what they still do, but originally you would set it on fire and see how much heat was released by the fire. If you had a thermometer in a glass of water, you could estimate how much energy was produced by the fire by calculating how much water there was and how much the water changed temperature.", "I have to know: does hot food have more calories than cold food? I asked this to a dietician and she got triggered AF."], "text_urls": [[], ["https://en.wikipedia.org/wiki/Calorimeter"], [], [], [], [], [], []], "score": [1503, 164, 54, 38, 20, 10, 6, 3]}}, {"q_id": "7y1pym", "category": "Repost", "title": "How does Earth's atmosphere not get sucked into the vacuum of space?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ducw825", "ducwr5r"], "text": ["Because gravity. I mean, that's really the whole answer. Gravity holds the atmosphere to the Earth.", "Two reasons: First, space doesn't 'suck' anything. The vacuum of space does not exert *any* force on the atmosphere at all. While we may refer to a vacuum as 'sucking' that's a misnomer. As you said, areas of high pressure move to areas of low pressure, so as to equalize the pressure. However, all of that force is coming from the area of high pressure. An area of low pressure is not 'pulling' anything to it, so much as an area of high pressure is pushing into it. Basically speaking, whenever you have a grouping of gas/liquid, it tries to spread out as much as it can. So, when there's an available path to a lower pressure region, it will expand to have a lower overall pressure itself. Since we now know that space isn't 'sucking' at the atmosphere, but rather the atmosphere is 'pushing' into space, what does that mean? Well, first, as you ascend earth's atmosphere, it gets thinner, and thinner. Also that as you descend it gets thicker, and thicker. So why doesn't all that thick spread into that thin, to become an even density? Gravity. If you can imagine that gravity curves space around an object, you'll see that the most 'intense' curve is at the object itself. So when earth is making all this gravity everywhere, it's strongest around the densest parts, or the outer core. For our purposes, let's agree that gravity is strongest at the surface, and gets progressively weaker as you go farther out. So two things combine here: * Air pressure and is trying to push air up and out into space. * Gravity is trying to hold air to the planet. Eventually, the farther away the gases get, the gravity becomes weaker. However, because the atmosphere is much less dense up there, there's less air pressure to keep pushing itself up and away. End result? Thick atmosphere at the bottom, getting thinner, and thinner, until it stops being an atmosphere. The atmosphere we have now is the result of planetary evolution, and it's not stable. At one point, it's likely that a much denser atmosphere would have lost some of itself to space because earth's gravity couldn't contain *all* of it. What we're left with is all the atmosphere that earth *could* contain, and thus it's not escaping anymore because what's here can no longer overcome gravity to get far enough away to be stripped off by solar winds and the like. ***Edit*** A simpler thought experiment, in case anyone wants to explain it to an actual 5 year old, or they don't fully understand the idea's above: *Atmospheres are like lots of springs all over a planets surface. Gravity is pulling down on them, compressing them. Space doesn't uncoil the springs in any way, the springs are naturally trying to uncoil on their own, because space doesn't provide a wall or any pressure to keep them coiled. Gravity is the only thing keeping them compressed and coiled.* *When you're in a space-ship, the walls and other enclosing materials are pressing the springs into the density we require for functioning. When you poke a hole in the wall, the springs don't get dragged out, they simply decompress, or uncoil, and 'jump' out of the hole as fast as they can until they're not compressed anymore.*"], "text_urls": [[], []], "score": [33, 10]}}, {"q_id": "7y1scf", "category": "Repost", "title": "Why do car manufacturers allow cars to go way faster than speed limits?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ducx34d", "ducx01f"], "text": ["You are allowed to go faster in order to overtake. Different speed limits in different countries. Top speed limits change over time (in NZ we just changed ours to 110 km/hr). Marketing and bragging rights. The customer is always right.", "Takes more power to get to 65 than it does to coast at 65. Need to horsepower to get to the speed. Saw this question a couple days ago and that was the answer I saw."], "text_urls": [[], []], "score": [4, 3]}}, {"q_id": "7y6e0h", "category": "Repost", "title": "How do air-conditioners produce cold air when it's so hot outside?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dudy2mk"], "text": ["An air conditioner can work as long as the compressed gas in the outside part can condense into a liquid. Let's look at how an air conditioner works. The science behind it is that when you squash a gas, it gets hot, and when you allow a gas to expand, it gets cold. You can feel this when you pump up a bike tyre - the pump gets hot as the gas is squashed. You can feel the other way when you use deodorant - the compressed gas expands as you release it, and becomes cold. So, an air conditioner has an amount of gas inside it. The pump squashes that gas, and it gets hot. This hot gas goes to the coils outside. As long as the outside is not as hot as the gas - 65\u00b0C is typical - it cools down, giving up that heat to the air outside. Provided it can give up enough heat, the gas condenses to a hot liquid, because of the high pressure. Then this liquid then passes through a valve that drops the pressure. Some of it instantly evaporates, and making that liquid evaporate (or, boil) takes heat energy. Just like that deodorant, the temperature of it drops. Now it is cold, and it is passed through the coils on the inside. Here it pulls heat out of the air inside the room, and this heat is used to boil off the liquid, back into a gas. This gas then flows back to the pump, to be compresed again, which heats it up, and it gives up the heat pulled from the inside of the room (together with heat from the work done by the pump) in the outside coils again. So as long as it is not too hot for the high pressure, hot gas to condense to a liquid, the air conditioner will work fine."], "text_urls": [[]], "score": [6]}}, {"q_id": "7y90m3", "category": "Repost", "title": "Why do chrome and mirrorlike objects have a distinct \"silvery\" color when they are just reflecting their surroundings?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["duekxje", "duei7fs"], "text": ["Yo ho ho! Yer not alone in askin', and kind strangers have explained: 1. [ELI5: Why do we recognize that mirrors are \"silver\" when they appear to be the exact same color as what they are reflecting? ]( URL_0 ) ^(_ > 1000 comments_) 1. [ELI5: Why is it that we think of mirrors as being silver colored, even though they reflect the exact colors of objects around them? ]( URL_3 ) ^(_ > 100 comments_) 1. [ELI5:Why do I perceive mirrors as silver even when they are reflecting other (non-silver) colors? ]( URL_2 ) ^(_22 comments_) 1. [Why are mirrors drawn as silver/grey when they reflect any colors from their surroundings? ]( URL_1 ) ^(_20 comments_) 1. [ELI5: how can mirrors reflect an image and still \"look silver\" if the image has no silver or grey in it? ]( URL_5 ) ^(_6 comments_) 1. [ELI5: Why do I perceive mirrors and other reflective surfaces as silver? Don't they really just have the color of whatever they're reflecting? ]( URL_4 ) ^(_10 comments_)", "What you are seeing is the color silver. I know. This doesn't sound very interesting. Silver absorbs a little bit of the visible spectrum just like other colors do. Mirrors are just metal coated glass, or bare polished metal, just like chrome."], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/4fa2pp/eli5_why_do_we_recognize_that_mirrors_are_silver/", "https://www.reddit.com/r/NoStupidQuestions/comments/4st7vf/why_are_mirrors_drawn_as_silvergrey_when_they/", "https://www.reddit.com/r/explainlikeimfive/comments/1vt8xa/eli5why_do_i_perceive_mirrors_as_silver_even_when/", "https://www.reddit.com/r/explainlikeimfive/comments/5lw1g0/eli5_why_is_it_that_we_think_of_mirrors_as_being/", "https://www.reddit.com/r/explainlikeimfive/comments/1zt7sj/eli5_why_do_i_perceive_mirrors_and_other/", "https://www.reddit.com/r/explainlikeimfive/comments/1s75g1/eli5_how_can_mirrors_reflect_an_image_and_still/"], []], "score": [15, 4]}}, {"q_id": "7ya5fh", "category": "Repost", "title": "Why is it when someone gets hurt their instinct is to yell ow?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["duer7ps"], "text": ["It's not an instinct. It's learned behavior that varies based on your culture. You were raised from an infant to associate \"ow\" with pain, and it's *heavily* ingrained in you, but it's not an instinct. If you had been raised in Japan, you'd say \"ite\". If you had been raised speaking Arabic, you'd say \"Akh\". Different languages and cultures have different sounds for this. But all of them tend to be short and easy to say."], "text_urls": [[]], "score": [3]}}, {"q_id": "7yb4bn", "category": "Repost", "title": "Why is it that when my friends tap the top of my beer with the bottom of their (bottles), the beer foams and overflows?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["duf2lbj"], "text": ["If you do this a few times you'll find that the beer foams less each time and soon doesn't foam at all. This tells you it's coming from an ingredient in the beer that's used up by the tapping and foaming. After a beer stops foaming like this it tastes very \"flat\". The ingredient is carbonation, i.e., carbon dioxide gas that's mixed together with the beer in the fluid. The gas molecules are weakly bonded with the nearby beer molecules, very similar to a carbonated soda drink. Tapping the beer bottle sends a small shock wave through the fluid, and the shock breaks the bonds, releasing the gas molecules to rise to the top and generate foam. Normally only the molecules at the top surface of the fluid (the ones exposed to air) are released, so the process is slow and the beer doesn't foam up much. The shock wave releases the gas through the whole volume of the fluid in a much faster process, so the foam overflows the space at the top of the bottle and spews out."], "text_urls": [[]], "score": [6]}}, {"q_id": "7ybpxa", "category": "Repost", "title": "Why is it that whenever we take a picture of the sun or moon it looks so much smaller in the picture than it does with our naked eye?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["duf443e"], "text": ["Because the human brain is horrible at estimating the size of things like the moon in the sky and our brain actually lies to us about their size. When you take and look at a picture, you're removing it from the context that the brain can't cope with and putting into a context that's more familiar. Here's an article that goes into detail about it and shows examples of the effect: URL_0"], "text_urls": [["http://www.skyandtelescope.com/observing/moon-illusion-confusion11252015/"]], "score": [3]}}, {"q_id": "7ydlcc", "category": "Repost", "title": "Why are Directors praised for a good story? I mean, for good cinematography, sure. But they don't write the story.", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dufla55"], "text": ["The story that is presented to the viewers is ultimately delivered via the director's choices. The same story in the hands of a less talented director wouldn't be as engaging and enjoyable for the audience."], "text_urls": [[]], "score": [6]}}, {"q_id": "7ydvau", "category": "Repost", "title": "Is there any logical reason as to why toilet bowls have a column of water sitting at the bottom?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dufoqmc", "dufoynm", "dufrvio"], "text": ["Yes, the water acts as an air seal to prevent sewer gas rising up from the toilet into your room. Most people don't want to smell old poop water.", "It is a built in water trap. It prevents waste smells and gasses from coming back up after flushing. Most drains have a similar set up. If you look at the side of the base of the back of a toilet you can see the way the drain is designed.", "Which \"column of water\" are you referring to? The bowl has water in it so you don't deliver waste directly onto the porcelain. Not a big deal for urine, may be a big deal for excrement. The piping (first ceramic then metal or plastic) has an elbow in it (or a \"J\" then connected to an inverted \"J\") to create as others have said an air trap. This prevents the horrid smell of waste from your sewage line from entering your home. In addition, past that dual \"J\" air trap, there's another pipe that leads upwards from the sewer line to above the roof. This is a vent that allows gases created by bacteria to vent and not bubble up through the double \"J\" air trap. Sewage system plumbing has been around for a while and is quite well tested."], "text_urls": [[], [], []], "score": [50, 11, 9]}}, {"q_id": "7ygzh5", "category": "Repost", "title": "How will an unprotected human body die in space?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dugh92h"], "text": ["Due to the low pressure, oxygen will move across your lungs from your blood into the vacuum. You will fall unconscious within a matter of seconds, and die due to the lack of oxygen, asphyxiation, within a few minutes."], "text_urls": [[]], "score": [13]}}, {"q_id": "7yi9qr", "category": "Repost", "title": "depression.", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dugqxn8", "dugsl9m"], "text": ["Depression is the lack of emotion it looks like sadness but inside of you it feels empty there is no emotion everything feels worthless you feel worthless and nothing has any meaning it feels like you wasted everything you got and ended up in the deepest most miserable hole ever and no one understands how you feel and that makes it worse. Being sad is lasts for a while and its gone and then you feel better while when you are depressed it doesn't go away and the longer it is you feel worse if you need me to clarify something i will just ask on Source:myself", "Avast ye! Yer not alone in askin', and kind strangers have explained: 1. [ELI5: Is there a difference between clinical depression and depression triggered by a traumatic event? ]( URL_3 ) ^(_19 comments_) 1. [ELI5: What is depression? ]( URL_5 ) ^(_23 comments_) 1. [ELI5: Why do people who have depression sleep a lot? ]( URL_2 ) ^(_11 comments_) 1. [ELI5: Depression ]( URL_8 ) ^(_50 comments_) 1. [ELI5: When suffering with depression, what is the physical feeling you get in your chest? Sort of like an actual sinking feeling. ]( URL_6 ) ^(_73 comments_) 1. [ELI5: What is anxiety and depression? Are they related to eachother? ]( URL_1 ) ^(_6 comments_) 1. [ELI5: Depression. How can someone not be able to get up and do things? ]( URL_9 ) ^(_88 comments_) 1. [ELI5: Why is Depression considered a real illness when it is all in the person's mind? ]( URL_0 ) ^(_ > 100 comments_) 1. [ELI5: What is anxiety and depression? Are they related to eachother? ]( URL_1 ) ^(_6 comments_) 1. [ELI5: Depression ]( URL_8 ) ^(_50 comments_) 1. [ELI5: What is the difference between \"true\" depression and low self-esteem/feeling sad? ]( URL_7 ) ^(_8 comments_) 1. [ELI5: How to explain depression to my spouse who believes it's not a real disease and can be controlled by deciding to not be sad. ]( URL_4 ) ^(_ > 100 comments_)"], "text_urls": [[], ["https://www.reddit.com/r/explainlikeimfive/comments/344vez/eli5_why_is_depression_considered_a_real_illness/", "https://www.reddit.com/r/explainlikeimfive/comments/2ibgx4/eli5_what_is_anxiety_and_depression_are_they/", "https://www.reddit.com/r/explainlikeimfive/comments/6c7m43/eli5_why_do_people_who_have_depression_sleep_a_lot/", "https://www.reddit.com/r/explainlikeimfive/comments/7ahdom/eli5_is_there_a_difference_between_clinical/", "https://www.reddit.com/r/explainlikeimfive/comments/23xtul/eli5_how_to_explain_depression_to_my_spouse_who/", "https://www.reddit.com/r/explainlikeimfive/comments/36kstt/eli5_what_is_depression/", "https://www.reddit.com/r/explainlikeimfive/comments/6ru6xg/eli5_when_suffering_with_depression_what_is_the/", "https://www.reddit.com/r/explainlikeimfive/comments/2y0orq/eli5_what_is_the_difference_between_true/", "https://www.reddit.com/r/explainlikeimfive/comments/1l90le/eli5_depression/", "https://www.reddit.com/r/explainlikeimfive/comments/2tsu9g/eli5_depression_how_can_someone_not_be_able_to/"]], "score": [9, 7]}}, {"q_id": "7yit5l", "category": "Repost", "title": "Why do commercial flights take longer going to a destination then coming back when they fly the same distance and course? Why can planes fly faster at higher altitudes?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dugvg57"], "text": ["They take longer going west because they're heading against the general wind direction. Same route going east, the wind is helping so it's faster. Higher altitude: the air is thinner, less friction."], "text_urls": [[]], "score": [4]}}, {"q_id": "7ykalx", "category": "Repost", "title": "How can snowboarders fall 5 stories and not break their legs ?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["duh7oux", "duh834d", "duh86e7"], "text": ["A) Snow is softer than dirt B) Just like motorcycle riders, they try to land on sloped ground so you're *not* dealing with the entire impact as a blow to the legs", "Landing on a steep slope (like in the Olympic events) allows the person to slowly slowly decrease their speed of the fall. If the landing was flat, they would all suffer broken bones.", "When falling, It isn't the collected kinetic energy that kills your bones, It's the sudden stop. Or more importantly, the change in momentum as you go from falling really fast to stopping in an instant. When a snowboarder or ski jumper fall down great distances they tend to land on a slope that slows their downward momentum over a longer period of time then a flat landing would."], "text_urls": [[], [], []], "score": [4, 3, 3]}}, {"q_id": "7ylpsw", "category": "Repost", "title": "How does dry cleaning work?", "title_urls": {"url": []}, "selftext": "I struggle to get my head round the magical concept of how one can clean things without any water, hoping someone can help me wrap my head around it?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["duhh5yl"], "text": ["Yarr! Yer not alone in askin', and kind strangers have explained: 1. [ELI5: What exactly is dry cleaning? ]( URL_2 ) ^(_ > 100 comments_) 1. [ELI5: How exactly does dry cleaning work? (And are dry clean-only labels a scam?) ]( URL_0 ) ^(_36 comments_) 1. [ELI5: How does dry cleaning work? ]( URL_5 ) ^(_4 comments_) 1. [ELI5: How does the process of Dry cleaning work? ]( URL_6 ) ^(_1 comment_) 1. [ELI5: How does dry cleaning work? ]( URL_3 ) ^(_9 comments_) 1. [ELI5: how does dry cleaning work and why do certain clothes need it? ]( URL_4 ) ^(_4 comments_) 1. [ELI5 How does dry-cleaning work? ]( URL_1 ) ^(_ > 100 comments_)"], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/61rs3f/eli5_how_exactly_does_dry_cleaning_work_and_are/", "https://www.reddit.com/r/explainlikeimfive/comments/vexeu/eli5_how_does_drycleaning_work/", "https://www.reddit.com/r/explainlikeimfive/comments/2i334z/eli5_what_exactly_is_dry_cleaning/", "https://www.reddit.com/r/explainlikeimfive/comments/6fyv8s/eli5_how_does_dry_cleaning_work/", "https://www.reddit.com/r/explainlikeimfive/comments/33714g/eli5_how_does_dry_cleaning_work_and_why_do/", "https://www.reddit.com/r/explainlikeimfive/comments/7gxtlu/eli5_how_does_dry_cleaning_work/", "https://www.reddit.com/r/explainlikeimfive/comments/6twi49/eli5_how_does_the_process_of_dry_cleaning_work/"]], "score": [9]}}, {"q_id": "7ym5fi", "category": "Repost", "title": "Why can a huge human whack a tiny fly mid air and its seemingly unhurt?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["duhks18", "duhxzzf", "duholhq"], "text": ["[u/stefonion]( URL_1 ) > [ URL_0 ]( URL_0 ) > When you swat a... well, anything, your hand builds up a small layer of air in front of it. When you swat a small thing, for a brief moment, they accelerate as the air layer pushes them. By the time your hand reaches them, they are not hit as hard as you think they were hit. > Now, if you take something larger than your hand, say, a friend's face, then the air layer is not big enough to push them, and they will feel the full force of the blow. > I am just trying to re-create this from memory. This was posted many months ago. > EDIT: Yes, this is exactly why fly swatters have holes, to remove as much of the lairheh as possible. It also helps that Flies have an exoskeleton and are very durable. If you scaled a fly up to the size of a cow, it would be the equivalent of a cow inside an army tank.", "As with pretty much any question about why small things behave differently than big things, it's the square-cube law. Let's say the fly is 1cm long, so roughly 180 times shorter than you. That means the cross-section of e.g. its legs and thus its toughness is 180^2 times smaller. However, it also means its mass is 180^3 smaller - and mass results in inertia, which is what would harm the fly when being swatted in the middle of the air. So effectively, the fly, *because* it is 180 times smaller than you, is actually 180 times tougher against being swatted. Note that this only applies to being swatted in the air - if you swat the fly against a solid surface, then your absolute strength acts upon it rather than inertia, and it will be squashed.", "Also, their very low mass means they accelerate quickly when hit so do not absorb as much energy as deformation as a heavier object would."], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/2qmo0x/eli5_how_does_a_fly_survive_a_powerful_swat_from/cn7i6ll/", "https://www.reddit.com/user/stefonio"], [], []], "score": [48, 5, 3]}}, {"q_id": "7yml5d", "category": "Repost", "title": "How is data/information stored on USB's, SSD's etc, able to be stored on these devices without power?", "title_urls": {"url": []}, "selftext": "You plug in a USB, place a file inside, unplug and it will still be there wjen you next plug it in. How does it stay there? My current thought is that the information is etched/embedded somewhere inside but I cannot seem to get my head around the concept!", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["duhmgir", "duhn1dc"], "text": ["Flash memory, the one used in USB drives and SSDs, is a form of EEPROM. They use floating gate transistors, in which electrons are effectively being trapped in a part of a component. Much like you do not need water running to keep a glass full, the trapped electrons will stay there until overwritten (or \"evaporated\", to keep the water analogy, but that takes quite a while), even if the power that put them there is no longer in place.", "Electrical capacitors (the most basic ones are just two metal plates separated by a plastic insulator) can store electrical charges (electrons) on the plates. So flash memory is composed of [floating gate transistors]( URL_0 ), that (if you look at the pictures in that article) basically have a tiny capacitor built-in, enough to hold a small charge of electrons on plates that are insulated in plastic, even if you cut off power. So the presence of a charge (electrons) is treated as a 1, and the absence as a 0, and that's how you get your data stored in 1's and 0's."], "text_urls": [[], ["https://en.wikipedia.org/wiki/Flash_memory"]], "score": [5, 4]}}, {"q_id": "7ypc5q", "category": "Repost", "title": "Why must we put our phones on airplane mode when on an airplane?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dui7bzd"], "text": ["In theory, this shouldn't be necessary; FAA regulations where you see the little disclaimer like \"this device cannot put out any harmful interference, and must accept any interference it puts out\" is mostly for airline safety: so that no consumer electronics will mess with aircraft instruments, as aircraft instruments don't have that restriction and can reject interference and give off interference with impunity. But, on the off-chance that there's a defect in someone's phone that makes it send out harmful interference, this would prevent it. And when you're dealing with hundreds of people in a metal tube packed to the brim with highly flammable liquids and being made to go several hundred miles per hour while flying several thousand feet above the surface of the Earth, you have as many failsafes as you can possibly have. The chance of any given phone causing EM interference is almost 0. The chance of a phone that is off or in airplane mode causing EM interference is a much closer number to 0, though, and when you're talking about airplane safety, closer to 0 is always better."], "text_urls": [[]], "score": [3]}}, {"q_id": "7yvczr", "category": "Repost", "title": "What is the god particle", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dujemwm", "dujfsut"], "text": ["\"The god particle\" is a nickname for the Higgs Boson. The nickname is from the title of a book, which was originally meant to be \"_The God**damn** Particle: If the Universe is the Answer, What is the Question?_\" (emphasis mine), but there was a certain amount of meddling from the publisher and the \"damn\" was dropped. Scientists tend not to like that name much, because the Higgs Boson has nothing more to do with any God than any other particle, and also finding it won't make us into gods; there is no actual sense in which it *is* a \"god particle\". The Higgs Boson is the particle associated with the Higgs field, which is a quite complex concept in particle physics which explains why some fundamental particles have mass even though you might expect them not to.", "I just learned this neat trick from another redditor this week. Use ' URL_2 ' instead of ' URL_1 ' for a more basic and easy to understand explanation of a topic! URL_0"], "text_urls": [[], ["https://simple.wikipedia.org/wiki/Higgs_boson", "en.wikipedia.org", "simple.wikipedia.org"]], "score": [12, 3]}}, {"q_id": "7yxh4r", "category": "Repost", "title": "How men and women are born in almost equal ratio on this planet?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dujv38n", "dujtjjd"], "text": ["1. Suppose male births are less common than female. 2. A newborn male then has better mating prospects than a newborn female, and therefore can expect to have more offspring. 3. Therefore parents genetically disposed to produce males tend to have more than average numbers of grandchildren born to them. 4. Therefore the genes for male-producing tendencies spread, and male births become more common. 5. As the 1:1 sex ratio is approached, the advantage associated with producing males dies away. 6. The same reasoning holds if females are substituted for males throughout. Therefore 1:1 is the equilibrium ratio. URL_0", "> How men and women are born in almost equal ratio on this planet? Human females have two X chromosomes (XX), while men have an X and a Y (XY). The sperm are generated with half of the genetic material of the male which means that roughly 50% get an X and the other 50% get a Y. All the female eggs will be getting an X because that is all the female has. So when the sperm meet the egg if the sperm has an X it will be a female child and if it has a Y then it will be male."], "text_urls": [["https://en.wikipedia.org/wiki/Fisher%27s_principle"], []], "score": [4, 3]}}, {"q_id": "7zcp8m", "category": "Repost", "title": "Why do most screens and other color pickers use red, blue, green instead of red, blue, yellow?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dun2mmz", "dun1o5t"], "text": ["Cyan, magenta and yellow are used in printing, and adding them up makes *black*. (Subtractive colours) A monitor however uses light where the three primary colours red, blue and green (say, LEDs) add up to white. (Additive colours)", "> Why do most screens and other color pickers use red, blue, green instead of red, blue, yellow? Because red, blue, and green are the primary colors of light (additive color) and cyan, magenta, and yellow are the primary pigments (subtractive color). Some people didn't learn cyan and magenta properly because colors are hard, instead calling them red and blue."], "text_urls": [[], []], "score": [6, 5]}}, {"q_id": "7zdah8", "category": "Repost", "title": "How is 85% of the ocean unexplored?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dun5u6r", "dun6m64", "dun6or8"], "text": ["oceans cover 71% of the earths surface. and that's not accounting for depth. ships travel at 30 miles an hour at most. oceans are 139.7 million square miles. which means if you stack size of the ocean one mile wide by 139.7 million miles long. it would take 531 years to traverse it all by ship. and that's just the surface, and not any depth.", "It\u2019s very deep and we are only just really developing submarines that can withstand the pressures at the ocean floors, and even then it only for limited time, plus it\u2019s pitch black so only the lighting the ship provides allows us to see anything.", "The sentence is usually referring to the fact that over 70% of the earth's surface is ocean-floor, and we have not explored much of the ocean floor. It's quite hard to get down there, thus exploration is expensive. Now you might think that there isn't a lot to be seen down there, but that is not true: on many expeditions they find new species on ground an in the open water."], "text_urls": [[], [], []], "score": [22, 6, 6]}}, {"q_id": "7zk129", "category": "Repost", "title": "Why do gas prices almost always include \u201c9/10\u201d of a cent, and how could we be expected to pay in portions of a penny anyway?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["duol70a"], "text": ["Basically when the tenth of a cent thing was introduced gas prices and wages were cheap enough that it gave gas stations a better degree of price control. If your price is $.10 going up to $.11 is a huge 10% increase in cost, so allowing them to make smaller adjustments let them price gas better. Since then prices have climbed but the tenth of a cent spot in the price has stuck around. As for how it actually works it relies on the fact that generally you buy multiple gallons of gas at once. So they just track the price like normal, and then when you finish filling up they just round up to the nearest cent and that's what you pay (the consumer always takes the loss in cases where you might have fractional cents like buying gas or sales tax)."], "text_urls": [[]], "score": [17]}}, {"q_id": "7zktts", "category": "Repost", "title": "How does GroupMe and other free services make money?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["duotczk"], "text": ["There\u2019s in old adage: if you receive something for free, you are the product They sell your info"], "text_urls": [[]], "score": [3]}}, {"q_id": "7zpo4u", "category": "Repost", "title": "When swiping a card, you would think if you swipe slowly the machine could get a better read and accept your card. Why is this not the case? Why do you have to swipe it fast?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["duprdm8", "dupstqx", "duptb28"], "text": ["A magnetic stripe readers operates by listening to a magnetic field for changes created by the passing card. A card moving faster creates what could be described as a \"louder\" \"message\". Ideally, a consistent, swift swipe produces the most clear \"message\" for the reader to pick up on, and it is also generally easier to maintain a more consistent card speed when the card is moving over the read head faster.", "THe way a magnetic stripe generates a signal is by what's called induction. This is basically where a changing magnetic field creates electricity, and it's how an electric generator would work. Now, put like that, would you expect an electric generator to create a bigger signal if you spin it faster than if you spin it slowly? It's that same principle that makes a faster swipe more effective than a slow swipe.", "A magnetic stripe contains particles of a material that can be magnetized in one direction or another. The reading of the card is enabled by *changes* in the direction of magnetism as you go along the stripe. As you move the card stripe along a reader (or vice versa), the changes in magnetism [induce a current pulse in a coil in the reader head]( URL_0 ). The faster you move the card, the larger the induced current pulses will be. But they will also be faster in time. At some point, there's an optimal trade-off for the reading circuitry that has to detect the pulses. Too slow and the current pulses will be too weak. Too fast and they may look like random noise and not be properly detected. **TL;DR** - It's kind of like Goldilocks and the three bears."], "text_urls": [[], [], ["https://dsp.stackexchange.com/questions/715/extracting-binary-magnetic-strip-card-data-from-raw-wav"]], "score": [75, 10, 4]}}, {"q_id": "7zq6oj", "category": "Repost", "title": "What exactly is a muscle \"knot?\" Is it a recognized medical phenomenon with a more technical definition? And is massage actually an effective treatment for them?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dupw5dq"], "text": ["Yer not alone in askin', and kind strangers have explained: 1. [ELI5: what exactly are knotted muscles in your back and where do they go when massage therapists work them out? ]( URL_4 ) ^(_28 comments_) 1. [What exactly are muscle knots? I assume they form under stress, but why do they stay formed for long periods of time? ]( URL_6 ) ^(_ > 100 comments_) 1. [ELI5: What is a muscle knot and what does it look like under the skin? ]( URL_5 ) ^(_ > 100 comments_) 1. [Eli5 how a \"knot\" in a muscle is formed, and how massaging the area gets rid of it. ]( URL_2 ) ^(_ > 100 comments_) 1. [ELI5: What exactly happens to muscles when you massage them and why is it good for them? ]( URL_0 ) ^(_7 comments_) 1. [ELI5:What actually happens when you \"pull\" a muscle? ]( URL_3 ) ^(_44 comments_) 1. [ELI5 What happens when the muscles in your back get knots? ]( URL_1 ) ^(_2 comments_)"], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/3k27mi/eli5_what_exactly_happens_to_muscles_when_you/", "https://www.reddit.com/r/explainlikeimfive/comments/6r11jc/eli5_what_happens_when_the_muscles_in_your_back/", "https://www.reddit.com/r/explainlikeimfive/comments/37n01p/eli5_how_a_knot_in_a_muscle_is_formed_and_how/", "https://www.reddit.com/r/explainlikeimfive/comments/1nmj8s/eli5what_actually_happens_when_you_pull_a_muscle/", "https://www.reddit.com/r/explainlikeimfive/comments/6h2d1j/eli5_what_exactly_are_knotted_muscles_in_your/", "https://www.reddit.com/r/explainlikeimfive/comments/26b84t/eli5_what_is_a_muscle_knot_and_what_does_it_look/", "https://www.reddit.com/r/explainlikeimfive/comments/164944/what_exactly_are_muscle_knots_i_assume_they_form/"]], "score": [3]}}, {"q_id": "7zqubg", "category": "Repost", "title": "What causes the sneeze reaction you get when looking at a bright light?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["duq1sph"], "text": ["There's a genetic component to it. It's referred to as the \"photic sneeze reflex\" or photoptarmosis. If you have the gene, you will sneeze as a result of looking directly at bright light. If you don't have the gene, you won't sneeze. I'm going to disagree with /u/mmont49 about it being caused by tears in the sinus ducts. I have this gene and the urge to sneeze is immediate and powerful, not enough time for tears to travel through sinus ducts. Plus I don't have the urge to sneeze on other occasions when tears travel through sinus ducts. It's an instinct directly triggered by the bright light."], "text_urls": [[]], "score": [3]}}, {"q_id": "7zr151", "category": "Repost", "title": "How can the entire world be in debt?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["duq2uue", "duq2vrm", "duq37i6", "duq33y7"], "text": ["All nations carry debt. But they aren't just borrowing from each other. They borrow from banks and from people. For example, a big chunk of the US national debt is in government bonds to private citizens. They do pay them, or at least they usually pay them, but they carry debt for the same reason people do; they value the things they get for the borrowed money so much they're willing to shoulder the additional interest payments.", "Debt is not \"bad.\" Debt is a tool. Its use can be bad, or can be good. Governments need debt because they need the ability to borrow money in the event that they don't raise enough money (through taxes) to pay their expenditures. Most countries owe debt to themselves. In the US, the debt is primarily owned by US entities - US citizens, the US government, state governments, etc. This just helps the government to function.", "Think of it in the same way as a person has debt: An average person in the US probably has several tens of thousands of dollars in debt. A mortgage, a car loan, student loans, credit card debt, etc. But that debt isn't a *bad* thing, because they get to use that house, that car, that education, and so on, while they pay those loans off. So as long as the payments are manageable and the person is able to slowly pay down those debts while still being able to live their life normally, that debt is a good thing, for the most part. And even though the total debt might be more money than a person makes in a year (or many years, especially if a mortgage is involved), that's nothing to worry about, as long as it's being used well. It's the same thing, in many ways, for a country. A country borrows money from lots of sources - from its citizens, in the form of bonds, from other countries who have lent money, even in the form of pensions or benefits owed to citizens. And as long as the country is able to pay back those people bit by bit, the country has made good use of that debt, and everyone's happy. So even a debt that seems to be a huge number isn't a bad thing until a government isn't able to pay its debts.", "> why is don't they pay them? Generally speaking, they are paying them. However, they continue to accrue new debts, and they don't generally pay off a single debt in one go but rather by an agreed upon schedule of installments."], "text_urls": [[], [], [], []], "score": [6, 5, 5, 3]}}, {"q_id": "7zs86q", "category": "Repost", "title": "How does insider trading work and what issues does it cause to make it so illegal?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["duqdfcz"], "text": ["For a five year old: As a parent I get to go grocery shopping and choose what cereal we have. When I purchase Cinnamon Toast Crunch (CTC), our favorite, and don\u2019t tell my children about it, I have an unfair advantage at breakfast the next day. When I ask my children what they want for breakfast, they say Frosted Flakes not knowing that there is CTC. When I pull out the CTC and pour myself a huge bowl that contains half the box, I reap the rewards from my unfair advantage and the kids fight it out for whatever is left. Just an example, not saying this has ever happened at my house....."], "text_urls": [[]], "score": [3]}}, {"q_id": "7zsqpu", "category": "Repost", "title": "Black Lights", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["duqh2zu"], "text": ["because some materials absorb ultraviolet light which has a lot of energy. then to get rid of the energy, they emit light at lower energy, usually as visible light. think of it as a set of stairs. you throw a ball to the top of the stairs (which takes a lot of energy), then the ball bounces back down one, two or three steps at a time releasing the energy in smaller amounts."], "text_urls": [[]], "score": [3]}}, {"q_id": "7zte18", "category": "Repost", "title": "What happens to a digital file when it's deleted", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["duqlyls"], "text": ["Your computer keeps a registry of the location of the data for that file. On a traditional Hard Disk Drive, that means the coordinates on the actual, physical, rotating disk (think track number on a CD - or record if you're old enough). On a Solid State Drive, it's a little more complicated with virtual locations and whatnot, but the idea is the same. Your data is stored at a location, and the registry knows where that location is. It's kind of like how the post office knows where your house is without keeping your entire house in the post office. When you write data to your drive, that location is protected so it can't be overwritten, because the registry tells the drive that the location is being used. When you delete a file, the entry in the registry is deleted. That's it. The post office forgets your address. The data remains there until that location is used for new data, at which point it is overwritten and \"deleted\". On an HDD, that means the metal disk is remagnetized (or demagnetized) at that location, switching the old combination of 1s and 0s to the new data. On an SDD, that means the NAND gates, which hold 1 or 0, are reset and again, changed to the new data. On HDDs, the process of changing the magnetization of the disk is not perfect. Remnants of the old pattern can be pulled up, which is what law enforcement agencies do when they go through disks to pull up deleted files."], "text_urls": [[]], "score": [4]}}, {"q_id": "7zwlr9", "category": "Repost", "title": "Why is warm water recommended for cleaning if germs grow better in warm conditions?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["durbt9r"], "text": ["To add onto what was already said, hot water has a better dissolution capability. So it will dissolve more dirt and other hindrance material before being saturated, while also dissolving them faster and easier."], "text_urls": [[]], "score": [6]}}, {"q_id": "7zwpei", "category": "Repost", "title": "I am a European. What is Mormonism? Is it a cult like Jehovas witnesses?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dura817", "dur9n3f"], "text": ["Is it a cult? You could argue both ways. Here's a brief-ish history of mormonism and you can decide. Here's a brief history of Mormonism: In the 1820's, Joseph Smith was a known con artist in Illinois running a scam where he would look into \"seer stones\" (small rocks with holes bored into them) claiming that they had the magic ability to tell him where treasure was buried. People would pay him to find treasure for them on their property, which of course he never did. Eventually he started claiming that and Angel came to him and told him the location of some golden plates with scriptures from ancient Native Americans on them. He insisted that no one was allowed to see the plates except him. He then uses the same seer stones that he did his treasure hunting with to \"translate\" the plates which became the book of mormon. The Book of Mormon tells the story of a family of Jews that fled Jerusalem, came to the Americas, got cursed with dark skin by god for being unrighteous, and descended into modern Native Americans. From there on he went on making a bunch of wild claims up (much like Scientology) and for some reason people believed him. He convinced one of his followers to pay to publish the Book of Mormon. After he got caught cheating with another women, he claimed that god or jesus (his story changed a lot) told him he should have multiple wives. Eventually a local newspaper published an article that exposed him and so he burned the press down and was arrested for it. got arrested for it. He and his brother were then killed by an angry mob who broke into the prison. After a bunch of fighting between his potential successors over which one of them would take over, one of them, Brigham Young, took his followers out to what is now Utah so they could live in peace and they became the modern Mormon Church. Eventually they got rid of some of the crazier elements like polygamy (at least the mainstream mormon church did. Some fundamentalist sects still practice it.) Now they're a multi-billion dollar business/religion.", "Yes, it was invented in the 1800\u2019s and is constantly changing, polygamy, no polygamy, no blacks, then allowing them. A lot is taken from Masons an they are told if the research Mormonism it shows a lack of faith. They claim Jesus was not one with God but a man who became a god. All people can do this too they claim. Families are together forever as long as they are in good standing with the church and give money. Salvation is earned by good works, a total opposite of what the Bible states. Christians are saved by believing Christ died for us to pay for our sins. If good works were required then it would be as if Christ\u2019s life was not enough. Ephesians2: 8,9 \u201cfor by grace we are saved by faith, and not by anything we do. It is a gift from God, so no man can boast. \u201c"], "text_urls": [[], []], "score": [6, 5]}}, {"q_id": "7zx3ci", "category": "Repost", "title": "Is there an absolute hot?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["durcjdc", "durcqe2", "durgirs", "durt1e3"], "text": ["With our current knowledge, there is a theoretical limit, called the Planck temperature. A body emit light with a wavelength corresponding to its temperature, and a body at the Planck temperature emit light with a wavelength of the Planck length. The Planck length is kind of our distance limit of the comprehension of the universe without a quantum gravity theory. If you want, at the Planck temperature, the energy involved are so high, we don't yet have a model that works to describe the behavior of matter. EDIT: as /u/JoJosh-The-Barbarian mentioned, the Planck temperature is not a limit as the higher temperature possible, but as the limit of our understanding", "We don't know. The wavelength of light emitted by an object is directly calculable from its temperature. As temperature increases (however momentarily), wavelength decreases. Plank theory suggests that the universe is quantised, meaning that there's a constant step between points in space, energy levels, etc... The Plank constant theorises that there's a minimum interval between any two energy levels of ~4.1 x 10^-15 electron volts. The plank length theorises that there's a minimum interval between any two points in space of ~1.6 x 10^-35 meters. Were the temperature of a particle to exceed ~1.4 x 10^32 degrees Kelvin, the wavelength of the emitted light would fall below the plank length. We have no idea what happens next, much less how the laws of physics behave at such extremes. The Plank length is so small and the Plank temperature so high that we've had a very hard time conducting meaningful scientific inquiry into them or assessing their meaningfulness.", "There are two good answers to this. The first is the \u201cPlanck temperature\u201d, which is about 1.42\u00d710^32 kelvins. In a system with that temperature, particles have so much energy that gravitational forces overwhelm the other forces like electromagnetism. We use quantum theory to model the behavior of particles, but we know that quantum theory does not properly account for gravity, so we know that it doesn't say anything sensible about what would happen at that temperature. A \u201cquantum theory of gravity\u201d, which is a sort of holy grail for physicists, might work to describe such a system. The second answer is in some sense the true counterpart to absolute zero. To explain it, I need to briefly talk about *negative temperature*. In thermodynamics, temperature is defined as the reciprocal of a quantity called *thermodynamic beta*. A high beta means that adding energy to a system will increase the entropy by a lot, while a low beta means that adding energy will only increase entropy a little. Cold systems have a large beta, and hot systems have a small beta. Absolute zero temperature corresponds to infinite beta \u2014 intuitively, this is one way of understanding why absolute zero can never be reached, because it's really an infinity in disguise. What if beta is negative? That would mean that adding energy to a system would *decrease* its entropy. This is forbidden by classical thermodynamics, but it's possible in special cases in quantum theory. For example, it can happen in systems where most particles have as much energy as they possibly can, so adding energy to the system would mean bumping up some other particles from their own diverse states to the common maximum. If a system has negative beta, then it also has negative temperature (because temperature is just the reciprocal of beta). But high beta is cold, and low beta is hot, so negative temperatures are hotter than positive temperatures! To illustrate, consider [this graph]( URL_0 ). (The graph has the right shape, but the labels aren't relevant to us.) We can take the X axis to represent temperature and the Y axis to represent beta. We can see that a positive temperature means a positive beta, a negative temperature means a negative beta, a large (far from zero) temperature means a small (close to zero) beta, and a small temperature means a large beta. We can see that as temperature approaches positive or negative infinity, beta approaches zero, and as temperature approaches zero, beta approaches positive infinity from one direction and negative infinity from the other. The absolute zero we know \u2014 absolute cold \u2014 means infinite positive beta. When we only look at the right side of the graph (positive temperature), it makes sense to handwave that this means zero temperature. Informally, we're dividing by infinity and getting zero. This is not really valid math, but it's a reasonable way to think about it. Absolute hot, on the other hand, would mean infinite *negative* beta. When we translate that to temperature, we'd be dividing by negative infinity and getting\u2026 also zero. (Again, this is not real math. Infinity and negative infinity are not real numbers and you can't divide by them.) So if we really want to talk about temperature instead of beta, then both absolute cold and absolute hot can be found at zero kelvin.", "VSauce did a great [video]( URL_0 ) on this back in 2012. Even though your question has been answered, I still highly suggest watching it if you have 15 minutes to spare!"], "text_urls": [[], [], ["https://qph.fs.quoracdn.net/main-qimg-c5be56e1b5d297b9995615a47707f52b"], ["https://m.youtube.com/watch?v=4fuHzC9aTik"]], "score": [110, 22, 15, 7]}}, {"q_id": "800fbw", "category": "Repost", "title": "What is the double slit experiment? Why is it important?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dus1zrv"], "text": ["[The experiment look like this]( URL_0 ), you send electrons into a screen with two slit, and behind this you got a screen on which you can see where the electrons land. If you believe the electrons are particles, in the sense that they are like a very \"small ball\", you would have points on two spots on the second screen corresponding to direct trajectories from the electron canon to the screen. But this is not what you get when you do the experiment. If you send electron one at a time, you get a point on the screen for each electron. But as you get more and more electron on the screen, you can see that it form a [pattern]( URL_1 ). It's exactly the same pattern, called interference pattern, that you would get if you send a wave through the slits. It means that the description of electrons as \"small ball\" is wrong, and electrons have wave-like properties. This experiment is the start of quantum mechanics."], "text_urls": [["https://upload.wikimedia.org/wikipedia/commons/thumb/c/cd/Double-slit.svg/640px-Double-slit.svg.png?1519514792549", "https://skullsinthestars.files.wordpress.com/2009/03/tonomuradoubleslit.jpg"]], "score": [10]}}, {"q_id": "803cl2", "category": "Repost", "title": "how can the radius of the observable universe be 46 billion light years while the universe itself is only 13 billion years old?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dusomg0"], "text": ["The universe itself is expanding still and doing so faster than the speed of light. Where nothing inside the universe can move faster than the speed of light, the expansion of it can. (In my very limited understanding) Where something was observed at point A and now at point B they can tell that the expansion is X."], "text_urls": [[]], "score": [3]}}, {"q_id": "8041sx", "category": "Repost", "title": "How do the image captcha work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dustfcy"], "text": ["That's Google's [\"No CAPTCHA\"]( URL_5 ) you're seeing. Basically, Google use: - the data they know about you (Are you signed into Google? Have they seen your IP before?) - [how you behave when solving the CAPTCHA]( URL_2 ) (Do you move the mouse like a human does, or does your mouse instantly shoot to the checkbox like a robot might do? Did you take some time reading the rest of the page first?) - [how you loaded the page]( URL_0 ) (did you load all the scripts and CSS like a browser does, or just the HTML like some scrapers do?) If their algorithm decides that you're a human, you just get the checkbox. Otherwise, you'll receive a challenge (generally image recognition with No CAPTCHA). Image recognition is a [difficult job]( URL_4 ) for computers, and requires quite a lot of computing power (most approaches use [neural networks]( URL_1 ), but how this is done isn't too important)... but recognising images is pretty easy for humans! How you solve the CAPTCHA is a useful clue too for Google's algorithm; humans and bots generally behave differently here, so that behaviour can feed into deciding whether you're a human. If the algorithm is *really* unsure, you'll get more sets of images to verify. It'll keep doing that until it's confident one way or the other, so that's why you sometimes get lots of image sets to classify. As a side benefit, [the image categories get used to train Google's image recognition networks]( URL_3 ), so Google gets better at image recognition with the data collected from CAPTCHAs."], "text_urls": [["https://security.stackexchange.com/questions/124532/what-triggers-googles-recaptcha", "https://en.wikipedia.org/wiki/Artificial_neural_network", "https://www.wired.com/2014/12/google-one-click-recaptcha/", "https://www.google.com/recaptcha/intro/", "https://en.wikipedia.org/wiki/Computer_vision", "https://security.googleblog.com/2014/12/are-you-robot-introducing-no-captcha.html"]], "score": [3]}}, {"q_id": "804vq9", "category": "Repost", "title": "What's a Fourrier transform", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["duta1m8"], "text": ["You know how when we write a number like 23.1 that means 2 tens, 3 ones, and 1 tenth? Any series of digits we write (and maybe one decimal point and minus sign if it needs it) can represent a number. Any integer can be represented by a series of digits and any real number can be approximated by one. Fourier transforms are very similar to this but for functions instead of numbers. If you don't know what a function is just consider it a line on a graph which we draw from one side to the other while never going backwards. We can add together a bunch of sine functions (they look about like ~, either longer or shorter and repeating forever in both directions) to get some function and any function (which meets certain common conditions) can be approximated by adding a bunch of these sine functions. A Fourier transform refers either to the \"digits\" which multiply the sines or the process of finding them. We can also do Fourier transforms in more dimensions by adding together some special multidimensional functions. It's actually a bit more complicated (\"digits\" which are imaginary numbers, continuous functions instead of a discrete number of \"digits\", etc.), but I hope this lets you get the basic idea. Uses: Once we do a Fourier transform on some function we call that having the function in the frequency domain. You can easily do some things in the frequency domain that are hard in what is usually called the time domain and then use an inverse Fourier transform to get back a transformed signal. If you have the Fourier transform of a bare audio signal (just the Fourier transform of the displacement of the microphone membrane from the pickup) then you can treat this literally. If you cut off all of the \"digits\" above a threshold frequency (or apply a filter which decreases the amplitude of the function we call the Fourier transform above a certain frequency) you can remove that frequency from the signal. When you do an inverse Fourier transform on the filtered Fourier transform and send the result to a speaker sound above that frequency will be gone. You can do the same for low frequencies, or the frequencies of human speech. You can apply different filters and make equalizers. You can store samples of frequencies humans hear well with more bits and those they hear less well with fewer bits in an audio file. This gives you smaller files. You can perform a Fourier transform on the signal from an antenna and filter it to get only some frequencies (or perform some sort of partial transform and not bother filtering). This lets you transmit and receive data in frequency bands and send multiple things over the air at the same time. You can do this without actually using a Fourier transform with various electronic components but the engineers who design the radio system use Fourier transforms to model it for their design. This is used in things like cell phones. Using a 2D Fourier transform and the trick above in the audio paragraph about dropping things people don't observe well you can get lossy image compression like JPEG so that image files are much smaller. You can also extend the frequency data to blank spots to get something like the Photoshop autoheal tool (I think, I don't know the theory behind this very well). Like /u/RiskyDodge mentions in this thread sometimes you can collect frequency data and then use an inverse Fourier transform to get the signal like with an MRI. Quantum mechanics uses Fourier transforms to describe the state of particles. Fourier transforms (or in some cases related things I've lumped together like Fourier series, discrete cosine transforms, etc.) have all sorts of use in modeling and manipulating things which can be thought of as having frequencies. This is true even for things you might not immediately think of that way like images."], "text_urls": [[]], "score": [7]}}, {"q_id": "805ufw", "category": "Repost", "title": "Why does our stomach hurt when we're excited or nervous?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["duti971", "dut9xs7"], "text": ["Your body is sending more blood to the organs you might need if you need to get shit done i.e. fight a bear - skeletal muscles, heart, lungs, brain. So your gut organs get less blood, and digestion takes a hit. Poor digestion causes nausea, upset stomach.", "It may be a triggering of the fight-or-flight response. To ancient humans, it would have been easier to fight or run from a predator on an empty stomach (ever tried playing football right after a thanksgiving meal?). Your body may be preparing to dump your stomach contents (through entrance or exit) in case you gotta act."], "text_urls": [[], []], "score": [11, 5]}}, {"q_id": "805vv4", "category": "Repost", "title": "Why are graphics cards good for mining crypto?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dut6k9d", "dut6wbw", "dut6atp"], "text": ["Graphic cards (GPU) and your normal processor (CPU) differ in the order they compute processes. A GPU uses parallel processing, meaning it can run several smaller calculations at the same time. A CPU uses series processing so it can more intensive calculations but only one at time. With crypto mining you are looking for the next hash of the block chain. Hashing algorithms aren't very intense and you want to try as many possible hashes quickly. This means the best method is parellel computing and therefore GPUs what you want to use.", "A GPU has hundreds or thousands of weak and simple processors A CPU has 1 to 16 strong and complex processors Crypto currency \"mining\" is calculating the next hash in the blockchain. A CPU is strong so a CPU Core can give you a hash to try extremely quickly but it only has up to 16 cores spitting out hashes. A GPU is weaker and takes significantly longer than a CPU to return a result, but has so many more cores that it comes out ahead. If you've got a 16 core CPU and a GTX 1080 with 2560 Cuda cores, then as long as a CPU core isn't returning results 160x faster than a Cuda core then the GPU will return more results per second and be better.", "Their processors are better suited to the particular math equations that crypto currency uses vs a CPU. CPUs are generalists that sacrifice raw speed to be able to do anything asked of them while Video cards are purpose designed to perform a specific and repetitive task very quickly. Specifically parallel processing of video. It just happens that the hashes used by crypto currency are similar to video processing so a video card can grind through them much more quickly and efficiently than a traditional CPU can. URL_0"], "text_urls": [[], [], ["https://en.bitcoin.it/wiki/Why_a_GPU_mines_faster_than_a_CPU"]], "score": [19, 8, 4]}}, {"q_id": "8063pb", "category": "Repost", "title": "What\u2019s the difference between copyright and trademark?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dut96ap", "dutnsfp"], "text": ["They are very different. Copyright is a system by which the creator of a work (a book, a song, a reddit post) may prevent others from copying that work. This allows the creator to profit from their work and to maintain creative control over it. Copyright exists to encourage people to create works. Trademark is a system by which a person or business may claim a symbol (a name, a logo, even a distinctive color) to represent them in trade. No competitor may use the same symbol to represent their products. This is what prevents anyone from starting their own company named \u201cApple Technologies\u201d and selling computers. Apple would object that this infringes their trademark. Trademark exists to prevent impersonation and consumer confusion. These two systems are frequently confused and conflated, particularly on the internet. They are often grouped together (along with patents, trade secrets, and other systems) under the umbrella of \u201cintellectual property\u201d despite the fact that the only thing they all have in common is that they aren't property. Example: Apple's logo is an apple with a bite out of it. It was (presumably) drawn by an artist at Apple. Apple holds a copyright to that image. If you copy that image and use it yourself, you may be infringing upon their copyright. But Apple doesn't have a copyright on the *idea* of an apple with a bite out of it. Absolutely nothing would stop you from creating your own image of an apple with a bite out of it as long as it isn't derived from Apple's. Apple also holds a *trademark* on their logo. If you use that logo to sell computers, you infringe their trademark. If you use your own drawing of an apple with a bite out of it to sell computers, you may still infringe upon their trademark even if there is no copyright issue. However, if you used that same drawing as a logo for a restaurant, you would not infringe upon Apple's trademark.", "One keeps someone from pretending to be you (trademark). The other keeps people from copying the stuff you write, draw, or record (copyright)."], "text_urls": [[], []], "score": [26, 3]}}, {"q_id": "80i0lh", "category": "Repost", "title": "How did English become a global language, and why English?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["duvpw0f"], "text": ["Because English was the dominant language of the superpowers of the 19th (UK) and 20th (USA) centuries. Countries tend to not change their language, no matter how shitty it is, unless they have to."], "text_urls": [[]], "score": [9]}}, {"q_id": "80j57k", "category": "Repost", "title": "Why are mirrors \u201cflipped\u201d left-to-right, and not top-to-bottom?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["duvzd7f", "duvzshd"], "text": ["They're actually flipped front to back, we just parse it as left to right because we are used to someone having to turn around to make their nose swap places with the back of their head.", "Everything is exactly the same. Wear a shirt with with writing and look in the mirror. Look at a letter in the mirror. Now look down. It's on the same side. It just looks backwards, because it was designed to be seen by someone in front of you."], "text_urls": [[], []], "score": [12, 5]}}, {"q_id": "80m5mj", "category": "Repost", "title": "Why does America drive with automatic transmission for the most part, while most of the world still drives manual transmissions?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["duwkrmz", "duwpe43", "duwir3d", "duwlrt9", "duwp2te", "duwnuxr", "duwnj0r", "duwon0s", "duwij5c", "duwoeph", "duwnk8r", "duwkt5z", "duwqr8n", "duwnppo", "duwnesk", "duwoiiq", "duwp04x", "duwn07d", "duwm77v", "duwmntk", "duwnw7n", "duwqtgi", "duwiw46", "duwqkt7", "duwndlk", "duwp58j", "duwpzgw", "duwsc4q"], "text": ["1) Current automatic transmissions are actually more efficient than manuals. 2) Very small diesel engines never caught on in the US. 3) US tends to have more powerful vehicles, so small efficiencies from manual are not needed. 4) Manual sucks in stop and go traffic. I like a stick, but I understand why a lot of people don't.", "Real answer for ya: America developed around it's population, and it's population will always migrate to wherever the job market is. These job markets more often than not are in big cities with corporations, factories, etc. Well most families, if given a choice (and stable income), would prefer a nice family home with plenty of space for kids, pets, and visitors rather than a cramped apartment in a noisey, bustling city. Thus, American culture gravitated towards endless suburbs instead of highrise apartments in every city. Consequentially, this upped the working class's average commute time by a substantial amount. Now, not everyone is a driving enthusiast that gets rock hard switching through gears of a manual transmission day in and day out on a 50 mile, round trip commute from work to their home. GM and Ford knew this, and started mass producing automatics and marketing them towards families because the automatic trans basically sold itself to the consumer. This was not the case in smaller, European countries with more established cities that had already built themselves around pedestrianism (I think that's the word), public transportation, and if needed, a cheap little manual transmission car to get you from point A to point B. Automatics aren't easy to sell to people that don't really need or want them. Hope this answered your question.", "Not sure if just America or everywhere. URL_0 Manual sales in Australia was already taking a dive in 2015", "I have been almost always driving a manual in Europe, then moved to the US for some time and got an automatic. After coming back to Europe I decided to look for an automatic as well - it's easier in city traffic and more convenient if you want to drink a coffee while driving. At the time it was an Accord with a 4 speed transmission. I found it to be quite a hassle actually, since the car was often in a wrong gear and I had to manipulate the throttle and brake to get the right gear before certain maneuvers. I think it just has to do with the way European streets are roads are build (not as straight and wide as in the US, a lot of passing, tight parking). Driving is more difficult in Europe and the manual transmission often helps. That being said, I now drive a manual and miss the convenience of an automatic transmission. I also think the dual clutch auto transmission is probably better suited for European roads and I think that the technology has matured enough for me to consider it for my next car (VW group had some issues with both electronics and clutch wearing prematurely in their first transmissions).", "While we're all here can someone ELI5: How on earth do 4 lanes of freeway traffic come to a stop, if there are no accidents? What the fuck is the deal?", "One reason, is Americans tend to like bigger cars. Back in the day that could mean a very heavy clutch pedal if it was manual. Also, automatics have been pushed as the luxury option.", "It's 2018. Automatics are superior. 20 years ago it was different but it's an attitude that lingers.", "This is gonna get buried, but I've had a few people tell me this reason. In many European countries, there are two \"levels\" of driver's licences, one for manual and one for automatic transmissions. People who pass the manual transmission test are allowed to drive automatics too, but not the other way around. Many new licencees lean on a manual car to take the manual test, so they don't get stranded with a car they can't drive. Now, you have the majority of the population able to drive a manual transmission, and auto manufactures can build these for cheaper. Cheaper cars attract more buyers (because they're able to drive them) so more manual cars make it into circulation. This encourages more people to licence standard transmissions... You see the cycle. **TL:DR;** It's because it's cheaper and because the drivers know how.", "I don\u2019t really know but probably because General Motors purchased the innovation of the automatic transmission and it was quite novel at the time. Since, people just thought it was easier and less work to concentrate on the gearing. Now people just get into car accidents because they\u2019re looking at their cell/mobile phones. I\u2019ve heard of more people going back to manual just because it\u2019s \u201cvintage\u201d and also easier to take care of. Plus zoom zoom.", "Generally speaking, American's don't have left feet. As a result, the only way they could drive clutch is if they used a hand clutch. While most Americans make more than $600,000/yr, many hand-clutch vehicles are still out of our price range. To accommodate our lack of left feet, we use automatic shift vehicles and rapidly stomp between pedals with our right foot.", "I\u2019m not sure most of the world uses manual transmissions, but the main reason I would assume is mainly price and ease of maintenance. A manual transmission is cheaper, lighter, and easier to maintain than an automatic transmissions system. That\u2019s about it. I assume performance between the two systems is basically the same about now, with all the advancements in car technology we\u2019ve had.", "Most of the people I know drive manual. I have driven both and currently have automatic. European roads are generally narrower, bendier and steeper than roads in the US so need more \"driving\". A manual gives more control on difficult corners and being able to select 2nd gear for complex maneuvers and tight parking is a definite boon. There is generally the feeling that you are more in control of the car and are \"driving\" it rather than \"being driven\". Add to that the fact that automatics are less fuel efficient - and fuel in Europe is expensive - and it is generally thought they are less reliable and more expensive to fix (this may no longer be true). Finally, there is the question of image. Automatics for a long time were seen as \"old ladies\" cars and for a lot of young men it would be extremely embarrassing to confess you drove an automatic - tantamount to saying you had a stairlift or wore adult diapers. However, this too is changing.", "In Czech Republic most people drive manuals. The reason is very simple - people want cheap cars that are cheap to run and cheap to maintain. The general consensus is that cheap cars with automatics cost more to run and maintain than their manual counterparts. If you have the money to shell out for a good car with a good auto, and you like that kind of thing, then so be it. Nobody really cares here, at worst your parents (who, if you're old enough, may have had to deal with commie block cars) will call you lazy. You're taught to drive a manual, most people around you drive a manual, and your first car (usually an old Skoda) will probably be a manual. Almost noone complains about driving a manual in traffic because it's normal. I've heard way more complaints about autos acting stupid and sometimes outright dangerous while driving on twisty roads. (Crappy cheap automatic transmission bias? Definitely.) Also, while drivers here can be a bit aggressive, they generally know pretty damn well how to drive.", "Manual transmission is cheaper. In the past it was more economical in terms of fuel efficiency. But now automatic and manual transmission aren't too different in terms of fuel economy, so there isn't much of a reason to drive manual now.", "I like manuals but I now drive a car with a CVT (continuous variable transmission). It's more fuel efficient than a human ever could be, and I don't have to pay attention to shifting in traffic. In my commute it's either stop-and-go city driving or open highway so there's no real advantage to having gear control, and the fuel efficiency in the city is leagues above what I could ever achieve with a manual, usually within 10-20% (30 vs. 35 mpg) of my highway fuel efficiency. Also, there are like 4 options for different rpms if I really need it.", "So we can eat our donuts and put on our makeup while we drive. It's called multi-tasking! Also, because teaching your kid to drive is already a terrifying affair... Much less trying to teach standard. Some would say it's laziness, but I prefer the word \"efficiency\". (We can afford the luxury, so why not)", "Simple because of the amount of traffic in large cities makes driving a manual more impratical. And as a whole, Americans drive more than other countries.", "A different point, I think the fact that most people in America basically have to own cars and aren't just reducing the number to those who enjoy the car. So like as a higher percentage of people who drive cars Europeans are bigger into cars.", "Ever see someone who has never driven an automatic drive one? Total confusion .", "How else am I gonna eat my cheeseburger and drive man? I believe like pre late 2000s manuals made more sense for miles/kilometer per gallon as manuals used less. In the US gas is cheaper than in the EU, hence why European cars tend to have 2.0 liter engines and Americans can get away with large V8's without breaking the bank. Nowadays manuals are outdated, they're no longer better for racing as automatic transmission have made huge leaps and bounds in terms of shifting speed and gas usage. Autos now get better gas mileage. Manuals are still cheaper, and easier to work on but it's really not that big of a deal. I am like 85% sure the above is correct lol. Manuals are fun tho, I miss my old one...think my next car will be one. Manuals made me a better driver too I think, since it forced me to be focused on that car and the road.", "Unless you're racing or hauling why wouldn't you want an auto?", "Historically, Americans have had a lot of disposable income and culturally seem willing pay a great deal of money for convenience. Automatics are expensive, but very convenient.", "I think the real question is what America\u2019s obsession with column shift gearboxes is! I don\u2019t know if it\u2019s just a movie thing, but column shift is essentially obsolete in most other places in the developed world.", "The overwhelming majority of electric vehicles use single-speed gearboxes, so the whole manual vs. automatic thing will eventually become moot", "American here! I just purchased a brand new car that is a manual. The salesman looked suprised he asked if I was comfortable with driving a manual. Also, I was taught how to drive in a manual vehicle.", "I live in the US (upstate NY) and drive a manual. I hope that I never have to return to automatic. I hate them! They lag when you step on the gas, I feel as if I have less control over my vehicle, and manuals are so much more fun to drive! I don't even mind it in city traffic. I honestly get bored and thus more distracted while driving an automatic because I don't have to pay as much attention to my driving.", "The majority of Americans cannot operate a manual transmission because they were never taught because their parents didn't know how to either. Source: am American who knows how to use a clutch", "Money. We don't get taxed on small things considered luxuries or unnecessary. Taxi driver in Ireland told me that air conditioning was an extra grand, auto transmission was same, power windows, door locks, etc. So a 20k car had and Additional 10k in on just taxes because those were luxury add ons. He bought used high millage cars from England because after shipping and even the constant repairs it was still cheaper to get a fully loaded car. Many others said the same and mind you I wa3a in Ireland for 2 weeks."], "text_urls": [[], [], ["http://www.afr.com/lifestyle/cars-bikes-and-boats/cars/manual-cars-face-extinction-as-congestion-triggers-a-clutch-backlash-20150614-ghni7m"], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], []], "score": [2588, 2201, 929, 211, 173, 99, 69, 53, 52, 36, 34, 31, 25, 24, 21, 19, 15, 12, 11, 9, 8, 7, 6, 5, 5, 5, 3, 3]}}, {"q_id": "80majp", "category": "Repost", "title": "How are psychiatric medications developed, if their mechanisms of action is often unknown?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["duwkvbf", "duwnge1", "duwlhkf", "duwnn8h"], "text": ["A lot of the time they are discovered by accident. In other words they don\u2019t usually intend to create psychiatric medicine, but find that certain other drugs just so happen to have beneficial effects for mental health.", "Tbh we don't really understand how Lithium works but it really does work. We know a lot though. We don't know enough not by a long way however. As a psychiatry trainee I do wish we had better insight into the neurology of mental illness. This is what should hopefully better inform which drugs treat specific illnesses. But our knowledge is definitely progressing very rapidly.", "I have ADHD, so this is anecdotal, but I've heard that the way that stimulants were found helpful in ADHD is that \"disturbed\" boys were given a stimulant just to see what happened. I don't think that it was in a malicious way, though. They saw that these children were functional after taking a stimulant. *takes Vyvanse*", "Initially, as you know, it started with coincidences. People who had psychiatric problems were given drugs that calmed them down, and eventually it was found that these drugs were also treating their psychiatric problems. Since then, discovery has led by finding molecules with similar structure, but recently we have been using something called high throughput processing. What this entails is having thousands of micro wells in a plate, each one of which has a few cells in it. We add chemicals to these cells that we know their effects (ex. Cause decrease in anxiett) and monitor how they work at the molecular level. We then look for similar molecular events when we add a random chemical to a micro well. This is kind of abstract so I'll give you an example. Imagine if an anxiety drug worked by increasing glucose intake into a cell. If we wanted to find a drug with similar properties, we would monitor the glucose uptake of cells in the wells we have. This is really a neat process, because you can test thousands of random drug candidates a day through this approach, all you have to do is add the drug to a micro well."], "text_urls": [[], [], [], []], "score": [62, 15, 11, 10]}}, {"q_id": "80qzhd", "category": "Repost", "title": "Why does changing the speed of audio affect the pitch too?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["duxjh9w"], "text": ["Pitch is a function of a soundwave's frequency as measured in hertz. Hertz is a measurement of cycles per second. If you take a soundwave of someone talking for 10 seconds and they are Ben Stein and talk in a monotone 150 hertz (I don't know if this is the frequency of Ben Stein's voice, but go with it) you have a soundwave that oscillates 1,500 times. (that is, 1500 peaks and valleys if you visualize the sound wave like you would in Audacity or some sound-editing program). If you play that back at 2x the speed, that 1500 oscillations is now happening in 5 seconds, so you end up at 300 hertz for your frequency, and now Ben Stein goes from sounding like an adult male to a very fast-talking child, what is commonly referred to as the \"chipmunk\" effect. All this is a really fancy way of saying that a sound's pitch is entirely a function of how fast it is, with higher pitches being faster. Therefore when you speed up the playback, you also raise the pitch."], "text_urls": [[]], "score": [5]}}, {"q_id": "80vgaa", "category": "Repost", "title": "The Fed", "title_urls": {"url": []}, "selftext": "Who are they? What do they do? And how do they do it? I know that they have the power to \"raise interest rates\" and are involved in \"making sure inflation is in check\" but I would have thought that that would be handled by market forces. Also, and I know that this could enter dangerous territory, but can someone please explain the controversy over the Fed. By that I mean that I know that some groups don't seem to like the Fed. Is that simply because of the lack of a gold standard (or some other equivalent) or is there something more to it? Or does me even asking that question just show that I really have no idea what is going on? Thanks in advance.", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["duyke96"], "text": ["The Federal Reserve is in charge of monetary policy in the United States. One of the most important aspects is setting the base interest rate. When inflation gets too high, the Fed will raise the interest rate. That's how they keep inflation in check. People don't like the Fed because of it's role in quantitative easing, which took place after the last banking crisis. Basically, this consisted of the Fed buying lots of lots of debt from the bond market, thereby helping to stabilise the economy. These are the same types of people who think we should be on the gold standard and who don't understand that the economy has moved on since the 1930's."], "text_urls": [[]], "score": [8]}}, {"q_id": "80wbfj", "category": "Repost", "title": "why (most of the time) girls have a better calligraphy than boys", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["duylrqw", "duyl66u"], "text": ["A few comments are mentioning that it's more valued among young girls. That's true, but there's another factor. Young girls have more developed fine motor skills than boys of the same age.", "Stereotypically speaking... Females tend to appreciate the cleanness and beauty of something. Males tend for speed and perceived efficiency. It\u2019s also part of the archaic system of women taking the notes while men spoke."], "text_urls": [[], []], "score": [5, 3]}}, {"q_id": "80xau7", "category": "Repost", "title": "What was the \"Dot-Com Bubble?\"", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["duytmmu"], "text": ["Back in the late 90s the Internet really took off commercially. There were lots of companies founded then (mostly Silicon Valley). Most of the big internet names you know (Google, Amazon, Ebay, etc) got their start then but there were many other companies that didn't make it (eToys, URL_0 ,etc) Investors were throwing money at these companies and running up their stock price. People became millionaires via stock options. Think bitcoin and crypto these days. Then it all came crashing down when the stock market started tanking in mid-2000. Suddenly a lot of those dotcom options were worthless again."], "text_urls": [["Pets.com"]], "score": [3]}}, {"q_id": "810l2m", "category": "Repost", "title": "what does cancer do to your body that eventually kills you?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["duzju6b", "duzk30i", "duzkm2f", "dv053hq"], "text": ["Cancer is jackass cells running around screwing with normal cells trying to do their job. Stops them from working. \"What's the big deal with some cells not working?\" you might ask. Well... It's a problem when an organ stops working.", "In same way as someone who will live in your flat, eat your food and use your computer). Plus - everyday he grows bigger, take more place and require more food. And every day clones of this person appear in other condo flats. First on same floor, then on others. In the end normal people will flee and move to other building. Unfortunately our cells don't have this luxery ...", "Cancer cells are simply cells that have certain mutations that allow them to reproduce themselves indefinitely and leave their location of origin in the body. When a cancer begins, the mutated cells constantly reproduce, making a tumor. The cells in the tumor need nutrients, water, oxygen, and space, which they steal from the non-cancerous cells around them. This interferes with the normal functioning of that tissue. Once the tumor metastasizes (move to a new location), new tumors form in different tissues that rob nutrients, etc. from that tissue, interfering with its normal functioning. Eventually, the cancer cells invade enough tissues that the body can no longer function properly and the person dies.", "Just to give you some personal examples; My mother has lung cancer. Her tumors will grow, pushing against her heart until it can no longer function properly. My grandmother has oral cancer. This has taken the form of a facial tumour that too will grow eventually making it impossible to breathe. I'm sure other forms of cancer have their own ways in which they kill. these are just the ones I know of."], "text_urls": [[], [], [], []], "score": [15, 12, 7, 3]}}, {"q_id": "812k93", "category": "Repost", "title": "Is the velocity of light not relative like other velocities?", "title_urls": {"url": []}, "selftext": "My understanding is that velocity has no meaning if it has nothing to be relative to. If you are going near the speed of light in a void with nothing else around to compare to it is the same as not moving. But how then is there a maximum speed in the universe? The speed of light could be slower or faster depending on what it is relative to.", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dv00uuc", "dv0156d", "dv00tcq"], "text": ["That's what makes relativity so complicated. **Because** light always moves at the same speed, it turns out that distance and time can't be constant.", "There are basically two principles of special relativity: 1. The laws of physics work the same in all reference frames. Among other things, this implies that position and velocity only make sense to talk about with respect to a chosen reference frame; they are \"relative\". 2. The speed of light is the same in all reference frames. So if you see something traveling past you at the speed of light, everyone else will see it traveling past them at the speed of light as well - no matter what their own speed is relative to you. This is why the speed of light is a maximum speed: you can't overtake the beam of light since it will appear to be traveling 299792458 m/s away from you regardless of how much energy you put into accelerating.", "That's the weird thing about the speed of light - unlike other speeds, it isn't relative. If you and I were both measuring the speed of the same light beam, and I'm sitting on earth while you're zooming through space at a very high speed, we'll both measure the same value for the speed of light. This is essentially Einstein's special theory of relativity."], "text_urls": [[], [], []], "score": [5, 5, 4]}}, {"q_id": "819cm5", "category": "Repost", "title": "What is past the borders of space?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dv1gsc9", "dv1gpq6"], "text": ["> I know space is expanding in all directions but whats past that? We don't know of any 'past' that. When we say space is expanding, we mean the space between any two distant objects is growing larger. However, there is no distance we are aware of at which there are no longer objects. So you have objects, in every direction, getting further apart, for infinity. If there is an 'edge' we lack evidence about it. > Also, whats between galaxies, why can't we travel between them? Much of the matter of the universe, but that's just because there's *so much* space between galaxies. Per square meter, it is extremely, extremely, super, super, duper, empty space. The main obstacle to traveling between galaxies is not the terrain itself, it's that it is *really, really, really* far away, and way way way farther than that to get anywhere. A roadtrip of x billion years doesn't have a lot of attraction, and it's hard to pack for. > Also, whats dark matter? Good question, although so far it appears to be \"something with mass\" which does not interact strongly with anything else outside of gravity. I.e. it doesn't block light, it doesn't bump into stuff, it goes right through objects, but it has a gravitational attraction.", "> I know space is expanding in all directions but whats past that? That isn't a meaningful question. Space appears to be infinite in extent and simply becoming larger. > Also, whats between galaxies, why can't we travel between them? Nothing. They are a huge distance apart and moving away from each other very rapidly. > Also, whats dark matter? Don't know. It seems to make gravity and nothing else."], "text_urls": [[], []], "score": [5, 3]}}, {"q_id": "81e7tr", "category": "Repost", "title": "How is the ratio between men and women in the world almost exactly 50% to 50%? What makes it not 58% to 42%? What causes this almost perfect mathematical relationship in something that is supposed to be completely random?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dv2i9ri", "dv2ic5g"], "text": ["Sample size matters. Flip a coin 10,000 times and you get very very close to 50/50 split but flip it twice and it's less likely you'll get one of each.", "It's probably the vast amount of people that brings the ratio so close to even. If you flip a coin 10 times, you might get seven heads and three tails, but if you flip that coin 7 billion times, then the actual percentages will come closer to the theoretical probability."], "text_urls": [[], []], "score": [8, 3]}}, {"q_id": "81em9m", "category": "Repost", "title": "Why is English the most universally accepted language in the world if it's the THIRD most spoken one?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dv2lftm", "dv2li2d"], "text": ["Because the British Empire was the most powerful force in the world for many years. It became the standard language for trade because the biggest navy, most powerful army & largest trading fleets used them. Then, America became the doming social, political, economic & military force in the world due to the World Wars. A language becomes popular because the people you want to speak to use it, not because of how many people speak it.", "\"Accepted language\" has to do with economic incentives, historical priority (\"lock in\" effects), and power centers, not total number of speakers. Similar reason to how European scholarship was dominated by Latin long after the language ceased to be used in day to day conversation."], "text_urls": [[], []], "score": [8, 5]}}, {"q_id": "81gs8m", "category": "Repost", "title": "How are people with bionic limbs able to control them?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dv33xe7"], "text": ["Hi, I am a rehab doc with several years experience treating amputees. There are two primary ways in which a prosthetic arm is controlled. The first is body-powered. What this means is that you use the energy from one movement to create the force necessary to cause the prosthetic device to move. An example would be bringing your shoulder forward (flexing) causes a pulley to tighten, which in turn opens a prosthetic hand. The second is myoelectric. What happens here is sensors are connected to intact muscles. By flexing that muscle, the computer within the device knows to make an action occur. This takes some practice, as activating individual muscles to cause an unfamiliar movement can be challenging. An example would be that flexing your anterior deltoid sends a signal which causes the device to open a prosthetic hand. Here's a systematic review that goes more in detail. URL_0"], "text_urls": [["https://www.rehab.research.va.gov/jour/2015/523/JRRD-2014-08-0192.html"]], "score": [10]}}, {"q_id": "81hppm", "category": "Repost", "title": "why do pigeons and some other birds bob their head as they walk about?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dv38tpk"], "text": ["Accord [to this website]( URL_0 ) it's also to stabilise vision. Pigeons and some birds don't track movement like we do so moving their head quickly from place to another helps them build snapshots of the world around them. Maybe a bit like a ballerina twirling - if they spun their head around at the same speed as their bodies are spinning the world would look like a blur to them, but ballerinas keep their heads still and kinda snap them around to minimise the blurring (and of course this lessens there dizziness!)."], "text_urls": [["http://www.loc.gov/rr/scitech/mysteries/pigeon.html"]], "score": [3]}}, {"q_id": "81m4ce", "category": "Repost", "title": "What makes cling film / plastic wrap stick?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dv3w0ax"], "text": ["The plastic when pulled from the roll produces an electrostatic charge. Ever rub a balloon on your hair and stick it to the wall? It\u2019s like that. That is why when you try to use plastic wrap on a metal bowl it doesn\u2019t work as well. The metal disperses the charge."], "text_urls": [[]], "score": [5]}}, {"q_id": "81q6i3", "category": "Repost", "title": "Datamining in Videogames", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dv4bc8l", "dv4bdec", "dv4ew4i"], "text": ["Sometimes it\u2019s content that\u2019s not finished prior to release. Other times it\u2019s finished and put on the disc for instance but then before the release they realise they can charge more for it so they just leave it inactive until it\u2019s needed. With recent games, especially those with large assets it can save time later having the user download them.", "They are there because in software development, you try and limit the amount of branches you have. If we have a base game, and I'm off adding in one hero, you're adding in another, and Joe is doing bug fixes, we are probably all going to be modifying the same files for this. The answer to having to modify the same files is version control software, such as GitHub. This way, we can each start a branch for our own work to keep it separate. However, as we continue to work on stuff, the more we touch before committing back into the Master branch (the one you publish from), the more likely we are to run into conflicts when we try and merge. To prevent potential chaos down the line, stuff will be merged into the code base early and often (basically at stages where we may not have everything fully implemented and polished, but not breaking anything), but just have options on it to not be accessible yet. This does mean that the raw files will have some data in them that someone can mine, but it really simplifies the development process.", "\"Datamining\" is just looking through the game's data files to see what's there. Often times, there are plenty of things in the game's data that are either not accessible through normal means, or not accessible yet. Like when a new patch comes out for an online game, people will look through all the new data files and list all of the new things / changes made."], "text_urls": [[], [], []], "score": [23, 18, 3]}}, {"q_id": "81qefu", "category": "Repost", "title": "Why is ADD / ADHD treated with stimulants instead of depressants?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dv4dcdd"], "text": ["You're right, it's counter intuitive. To understand it you have to think of it not as hyperactivity but the inability to focus or concentrate on a task, a bit like being fatigued. It's the attention deficit part of ADHD. The stimulants act to enable the person to concentrate on a task and not be distracted. It rebalances the attention deficit."], "text_urls": [[]], "score": [3]}}, {"q_id": "81r5z5", "category": "Repost", "title": "Why does salt melt ice?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dv4ii95"], "text": ["I don't think it melts ice, it the raises the freezing temperature of water... or thereabouts."], "text_urls": [[]], "score": [3]}}, {"q_id": "81uw0u", "category": "Repost", "title": "Why does food taste different warm than it does cold?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dv5coxo"], "text": ["Most flavors you taste are detected with your nose. You can taste 5 flavors with your tongue, but smell about 1 trillion odors/chemicals. When you heat up your food the odiferous chemicals in the food gain energy and evaporate, allowing you to be able to smell them easier. Thus making the food taste different."], "text_urls": [[]], "score": [4]}}, {"q_id": "81ywlf", "category": "Repost", "title": "Machine Learning", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dv66v0v", "dv68twa"], "text": ["Machine learning is simply using data in a computer to teach the machine learning model how everything works. In a ML model, you pass in data known as training data. It\u2019s the data that you want to work on, say to classify or predict the values. The model contains values called weights which are used by equations to do the task. Now either it can be right or wrong. So slowly over time using different optimisation methods, the model is made to change its weights which changes its decisions. So eventually, the predictions start becoming increasingly correct. Now this model which was trained is used to predict the results that you need. Some different models have their own \u2018quirks\u2019 that are handy at different applications.", "Instead of telling the computer what to do to win a game, you tell it the rules and what the winning conditions are. Then you let the computer run thousands of games, each time it learns something from the games and starts working out the best way to win. Say for a first person shooter game you might tell current standard AI to find cover if it's being shot and shoot back. Machine learning you would tell the AI that the win condition is to kill the player. The rules are that it can move, shoot and use cover. The first few thousand runs it will probably just run out and get shot, that's a loss so it will start trying other things within the rules. A few more thousand runs and it's shooting back with great accuracy but still not winning 100% of the time, so time to try new things within the rules. Eventually after thousands more runs the Machine Learning AI will learn to take cover, learned to hide from the player for an ambush, maybe even learned to flank the player."], "text_urls": [[], []], "score": [3, 3]}}, {"q_id": "825z5i", "category": "Repost", "title": "why are some URL's, like Wikipedia, specific and others just a string of letters and numbers?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dv7mivu"], "text": ["as boring as the answer I'm about to give is, it most often just comes down to \"Because that's how the specific website handles things\". Url's are man designed for a specific purpose. Wikipedia has most of its urls descriptive of the content of the page, because they don't need a lot of information being passed around. other have a lot of data that needs to be passed into the url and while they could have it in plain text it is often more efficient to encode it to shorten the string a bit. The url might also be dynamically created (say, YouTube video identifiers) in which case base 64 encoding is better for compactness sake than a long base 10 number or some human-readable string. When you're designing a website you can design the url to be nearly whatever best fits your purpose."], "text_urls": [[]], "score": [7]}}, {"q_id": "82787k", "category": "Repost", "title": "Where do absurdly wealthy people (as in $1bn+ net worth) keep their money?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dv7vsni"], "text": ["Usually these people are incredibly illiquid, so their wealth is an estimation based on the value of the assets they own (real estate, shares in their companies, and other assets). They\u2019re not keeping money in the bank - certainly not billions."], "text_urls": [[]], "score": [4]}}, {"q_id": "828g1k", "category": "Repost", "title": "How does a medicine 'know where to go'?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dv85pxk"], "text": ["> When I ingest the antibiotic how does it know to go to my hand and clear the bacterial infection? It doesn't. It goes everywhere and acts like it does in all those places, meaning it might clear up the bacteria in your hand but also in your foot. And screw with your gut bacteria, and your mouth flora, etc. That is where side effects come from."], "text_urls": [[]], "score": [7]}}, {"q_id": "82aeoj", "category": "Repost", "title": "How/When/Why are Hockey players allowed to fight?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dv8lcr7", "dv8mfd3"], "text": ["They are not. It's against the rules, and players can recover penalties for fighting. But it happens anyway.", "There's a whole series of unwritten rules about when players fight. It's often triggered by a player delivering a hit that's perceived as a cheap shot, regardless of whether that hit was technically legal. Other common triggers include hard hits on a star player or making too much contact with a goalie. The fights are seen as a way for players to police themselves. For example, if the best player on the opposing team has the puck, I may think twice before leveling him since I know that doing so will likely result in me being challenged to a fight by a bigger player on his team, which could be painful. There's a code of conduct surrounding the fights. Both players are expected to agree to the fight by \"dropping the gauntlet\" (i.e. throwing their gloves away) and the linesmen stop it once the combatants look tired or one of them falls down. Sucker punches and a variety of other dangerous tactics are not permitted and would be expected to result in a suspension. In the NHL, pushing and shoving will result in 2-minute minor penalties, and a fistfight will result in a 5-minute major penalty. There can be additional penalties or ejections for a variety of dirty tactics related to fights. At the college level, real fights are rare, in part because fighting is an automatic 5-minute major penalty, game misconduct, and suspension. In the NHL, fights are becoming decreasingly common and it's unusual for a team to have multiple enforcers/goons (fighting specialists)."], "text_urls": [[], []], "score": [3, 3]}}, {"q_id": "82di0a", "category": "Repost", "title": "What causes your stomach to rumble?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dv9cw6c"], "text": ["Recently I read somewhere that your stomach always makes those sounds as it\u2019s doing its thing. However, food muffles the noises so you don\u2019t hear them when you\u2019re full. Rumbling when you\u2019re not hungry seems to occur when your stomach is upset. I\u2019m guessing extra gas in the stomach produced at that time makes it more noticeable."], "text_urls": [[]], "score": [5]}}, {"q_id": "82eb1j", "category": "Repost", "title": "How did English become the most commonly spoken language in the world when the population density of other races far exceeded those of European/Caucasian descent?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dv9eo45", "dv9g9no"], "text": ["The British Empire. It doesn't matter how many people live in the countries where they originated now. It matters how many people were forced or incentivised to learn the language some centuries ago, and the British Empire covered nearly a quarter of the world's population at its greatest extent.", "The British Empire, followed by the United States, were superpowers during the time when globalization really took off. We British started it, and the Americans finished it. Cultural influence is also massive. Both the US and UK are cultural superpowers. There are plenty of stories of remote tribes somewhere in the jungle who, despite not having electricity, have still heard of Mr Bean or James Bond or The Beatles."], "text_urls": [[], []], "score": [20, 3]}}, {"q_id": "82ef22", "category": "Repost", "title": "Why does it feel like you are skipping through time when you fall asleep?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dv9gr78"], "text": ["Because you're unconscious, so it's easier for your brain to lose track / not keep account of time"], "text_urls": [[]], "score": [4]}}, {"q_id": "82hyyc", "category": "Repost", "title": "How come animals can drink from any water source(excluding salt water obviously) while we can\u2019t drink it unless we purify most of the contaminants?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dva6js5", "dva6vgj"], "text": ["Animals can drink from any water sources. They can also die from doing so. We have stricter guidelines for humans because we don't want humans to die unnecessarily.", "We can and do. See most of the poverty-stricken areas of the world. Those are by modern standards filthy sources of water. The trick is that they're used to that water. The germs and the bacteria in the water has gotten into our guts and either made a peaceful home there, or been in enough to get regularly kicked out without fuss by our immune systems. In the industrialized world, we have cleaned up the water, so we're now used to the chemicals and additives that are in it, as well as whatever local (smaller) blend of bacteria is in ours. It's why when you go somwhere, the water tastes funny. In other nations, even with clean water, it's normal to experience some stomach issues as the *new* bacteria come knocking and you have to adjust. Short version is that you can drink the dirty water and, unless it's got something REALLY nasty, you'll be sick but eventually get used to it."], "text_urls": [[], []], "score": [12, 3]}}, {"q_id": "82jj87", "category": "Repost", "title": "How do we know what the sun is made of and how much of each element makes it up?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dvajmet", "dvajgb1", "dvajnob"], "text": ["We look at the light it gives off Different elements give off different wavelengths of light when their electrons go from an excited state to a normal state. By looking at what peaks we see, and how tall they are, we can judge how much of what elements are in the sun [This is the spectrum of the sun]( URL_0 ), the Ha, H beta, H gamma, and H delta spikes all belong to Hydrogen. They're the tallest followed by the Helium(He) spikes which is how we know the sun is composed primarily of Hydrogen with some Helium and a smattering of other elements", "Spectrography. Basically by looking at the kind of light that comes from the sun you can see what elements make them up. When looking at the spectrum of light from any burning object there will be little black lines. These black lines are fairly unique for each element.", "We don't need to touch your house to know what color it is. The light from the Sun reveals its composition."], "text_urls": [["http://dailysolar.weebly.com/uploads/3/4/8/5/3485153/9810884.jpg"], [], []], "score": [7, 6, 3]}}, {"q_id": "82jrl4", "category": "Repost", "title": "Why does blood not rush to our feet, like it does to our head when we\u2019re upside down.", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dval6hl"], "text": ["The blood vessels in your lower body are pretty strong in order to avoid expanding too much under the constant force of the blood's weight."], "text_urls": [[]], "score": [8]}}, {"q_id": "82qfeb", "category": "Repost", "title": "Braille vs Raised letter for signage?", "title_urls": {"url": []}, "selftext": "For indoor navigation signage systems is it better to use raised letter than using braille? Though raised letters are hard to read, is it a better choice considering the fact that majority of users with visual challenges are not well versed with Braille?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dvc01fg"], "text": ["If you look at the statistics for blind people who can read letter forms by touch, it's even lower. Learning braille is a major effort, but it's a key differentiator between the 30% of the blind who are employed and the 70% who are not."], "text_urls": [[]], "score": [3]}}, {"q_id": "82vya8", "category": "Repost", "title": "Why snow is white ?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dvd80pa", "dvd8odl"], "text": ["The light from the sun is more or less white and the many tiny ice crystals in snow scatter it into pretty much all directions while the ice itself is pretty much colorless. That\u2019s why snow seems white (or more precisely whatever the dominant light color of the surrounding is).", "Snow is actually not white itself. Snow just _appears_ to be white, because when light enters a snow crystal it will bounce over to the next crystal, then to the next and so on. [Here is a good read on the subject.]( URL_0 )"], "text_urls": [[], ["https://science.howstuffworks.com/nature/climate-weather/atmospheric/question524.htm"]], "score": [6, 3]}}, {"q_id": "82zx0r", "category": "Repost", "title": "Why the shower curtain gets sucked in to the shower when the hot water is turned on?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dve0ur9", "dve8rgb"], "text": ["Hot air rises, and the hot water warms up the air inside the shower. This means the air inside really want to float up and away, but needs air to come in to replace it to fill the vacuum, sucking in the sides of the shower curtain. You can stop this from happening by simply leaving a bit of a gap between the wall and the curtain; you'll be able to feel air coming in there to replace the hot air floating up and out.", "I've searched tha seven seas fer an answer. Yer not alone in askin', and kind strangers have explained: 1. [ELI5:Why the fuck does the shower curtain move toward me only when the water is on? ]( URL_3 ) ^(_57 comments_) 1. [ELI5: When you take a shower, why does the shower curtain get pulled into the shower and annoy you? ]( URL_2 ) ^(_17 comments_) 1. [ELI5:Why do shower curtains move in towards you during a hot shower? ]( URL_5 ) ^(_8 comments_) 1. [ELI5: why does the shower curtain blow in when the shower is on ]( URL_1 ) ^(_6 comments_) 1. [ELI5: Why does my shower curtain drift inside the shower? ]( URL_4 ) ^(_6 comments_) 1. [ELI5: Why does the shower curtain 'blow' towards my body when I'm showering? ]( URL_0 ) ^(_5 comments_)"], "text_urls": [[], ["https://www.reddit.com/r/explainlikeimfive/comments/1pdqn5/eli5_why_does_the_shower_curtain_blow_towards_my/", "https://www.reddit.com/r/explainlikeimfive/comments/6iqe7x/eli5_why_does_the_shower_curtain_blow_in_when_the/", "https://www.reddit.com/r/explainlikeimfive/comments/42t15t/eli5_when_you_take_a_shower_why_does_the_shower/", "https://www.reddit.com/r/explainlikeimfive/comments/2jgh9f/eli5why_the_fuck_does_the_shower_curtain_move/", "https://www.reddit.com/r/explainlikeimfive/comments/2krnbj/eli5_why_does_my_shower_curtain_drift_inside_the/", "https://www.reddit.com/r/explainlikeimfive/comments/3mq5vn/eli5why_do_shower_curtains_move_in_towards_you/"]], "score": [8, 5]}}, {"q_id": "831g45", "category": "Repost", "title": "Why does squinting partially improve vision?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dvedxhq"], "text": ["It has to do with the optics. When light is squeezed through a small space, it is fainter but there isn't room for fuzziness. Even better than squinting is making a hole with your thumb and finger and viewing it through one eye, then closing it until the image sharpens. The optics are more easily understood by looking at a Camera Obscuea. A pinhole produces one, a baseball sized hole does not. With the pinhole, light for many point has to take 1 strait path through it. With a big hole, there are many paths and thus, it gets burred to the point where it is just white light against the wall."], "text_urls": [[]], "score": [9]}}, {"q_id": "837hjb", "category": "Repost", "title": "Torrenting. How do small files come from big files, and what is seeding and leeching?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dvfnpjo"], "text": ["The idea of the bittorrent protocol is that a large file, or collection of files, is split into many parts, each of which has a known checksum. Individual users with a complete \"part\" can share that part with other users, and the original person with the complete file[s] only needs to transmit as little as one complete copy of the file before many other users can have a complete copy. In addition, the protocol allows parts to be downloaded out of sequence. In this respect, a \"seeder\" is a term for a user with a complete copy of the file/files, and is sharing them with others. A leech is someone downloading the torrent, but that person can share already completed parts"], "text_urls": [[]], "score": [3]}}, {"q_id": "839k8z", "category": "Repost", "title": "Why does a word start to sound foreign the more you repeat it over and over out loud?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dvg4jr2"], "text": ["\u201cSemantic satiation\u201d is the phrase used to describe this. Basically, your brain becomes somewhat fatigued and numbed to the sound and the repition and over time as it tapers in neural response. This practice is actually described to combat speech anxiety where the repition of phrases decrease any associated fears or inhibitions with said phrases in the speaker."], "text_urls": [[]], "score": [3]}}, {"q_id": "83bugm", "category": "Repost", "title": "What does it mean when the ingredients of a food product say \u201cnatural flavors\u201d ?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dvgmvfn"], "text": ["If you grow fungis and other microbilogic stuff in a lab you can get all kinds of flavours. Its a missleading term. Technically it is all natural but it doesnt mean the flavour in your orange juice is from oranges..."], "text_urls": [[]], "score": [3]}}, {"q_id": "83fk38", "category": "Repost", "title": "Why is it that you hear about so many new amazing materials / inventions but you rarely see them being used or sold?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dvhefyx", "dvhhext", "dvheshu"], "text": ["A lot of the time these inventions or new \u201cbreakthroughs\u201d are sensationalized before they ever even get adequate testing. It\u2019s not uncommon for articles to report on something and make it sound like it\u2019s amazing when in reality scientists/organizations haven\u2019t even tested the stuff enough to definitively say whether or not it\u2019s actually useful/not dangerous/worth anyone\u2019s time. These studies unfortunately often take a lot of time (years) because they must be thoroughly tested to make sure they are safe for the general public/whoever would be using them and to also make sure that they actually work well. Edit: So to sum it up, the product must be tested before it\u2019s able to be put on the market for sale.", "Because you're hearing about things that are in laboratory testing, which is a LONG way from becoming a consumer product. Hence the jokes about \"Graphene can do everything except make it out of the lab\".", "You read about new inventions, *not* new products Scientists may figure out how to make a battery with 100x the energy density of a current phone battery, but it required 5 years to make a battery the size of a nickle that costs $5M and is prone to exploding. That's not a commercially viable product even though it is a large improvement in energy density. No one is going to pay $50M to get a phone that is half the thickness, its just not a marketable product at that price point. After a few decades of work someone might figure out how to make it in a cost effective way or they may determine that its actually impossible, but after the initial report of the discovery nothing exciting happens for a while so you hear about it once but never again. There are lots of awesome inventions and materials that can do anything *except leave the lab* because they're too expensive to implement on any reasonable scale. Carbon fiber took decades to find its way into consumer applications, it is now cheap enough to be used in a wide variety of things but it took a longgg time"], "text_urls": [[], [], []], "score": [48, 15, 14]}}, {"q_id": "83fo9u", "category": "Repost", "title": "Why are energy drinks bad for you?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dvhgnit"], "text": ["For the most part they're just soda with extra caffeine. The main ingredients in Rockstar and Monster are carbonated water and sugar. They have some other things like ginseng and taurine, but the sugar and caffeine are really the only things added in a large enough amount to really have an effect. > [According to a recent study, caffeine is the only ingredient that actually works. Participants who drank only caffeinated water had the same brain activity and response times as those consuming 5 Hour Energy]( URL_0 )"], "text_urls": [["https://www.caffeineinformer.com/energy-drink-ingredients"]], "score": [8]}}, {"q_id": "83irvj", "category": "Repost", "title": "Why do Cars have an odometer that goes to 160 Mph when the max speed limit is 70?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dvi3qko"], "text": ["The odometer doesn't go to 160 it goes to 999,999. The speedometer may go to 160 that's because people speed."], "text_urls": [[]], "score": [6]}}, {"q_id": "83jju4", "category": "Repost", "title": "Why can time be dilated or compressed but never go backwards?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dvi9w3q", "dvi9wlj"], "text": ["Yarr! Yer not alone in askin', and kind strangers have explained: 1. [ELI5: Why time moves forwards, not backwards. ]( URL_1 ) ^(_5 comments_) 1. [ELI5: Why is time travel backwards not possible? ]( URL_7 ) ^(_6 comments_) 1. [ELI5: What causes time to move forward? ]( URL_3 ) ^(_28 comments_) 1. [eli5: How can we know if time travel is/isn't possible? ]( URL_6 ) ^(_ > 100 comments_) 1. [ELI5: Why we cant travel backwards in time. ]( URL_2 ) ^(_4 comments_) 1. [ELI5: Why time travel cannot exist ]( URL_5 ) ^(_85 comments_) 1. [ELI5: Why can we travel forwards in time but not backwards? ]( URL_0 ) ^(_3 comments_) 1. [ELI5:Why can't we turn back time? ]( URL_4 ) ^(_20 comments_)", "Literally all of them. Without linear time all laws of the physical world fall apart. Our current understanding of the universe does not allow for actions to run in reverse. I believe the strongest assertion comes from energy expenditure/thermodynamics."], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/7qb5o2/eli5_why_can_we_travel_forwards_in_time_but_not/", "https://www.reddit.com/r/explainlikeimfive/comments/43la8x/eli5_why_time_moves_forwards_not_backwards/", "https://www.reddit.com/r/explainlikeimfive/comments/16ivdp/eli5_why_we_cant_travel_backwards_in_time/", "https://www.reddit.com/r/explainlikeimfive/comments/6t9m2g/eli5_what_causes_time_to_move_forward/", "https://www.reddit.com/r/explainlikeimfive/comments/3ymoic/eli5why_cant_we_turn_back_time/", "https://www.reddit.com/r/explainlikeimfive/comments/29mrzk/eli5_why_time_travel_cannot_exist/", "https://www.reddit.com/r/explainlikeimfive/comments/12nxfi/eli5_how_can_we_know_if_time_travel_isisnt/", "https://www.reddit.com/r/explainlikeimfive/comments/1kzo4a/eli5_why_is_time_travel_backwards_not_possible/"], []], "score": [10, 3]}}, {"q_id": "83mujf", "category": "Repost", "title": "Why is it so hard to make emulators? And why do they work with some games and not others?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dvj0wkq"], "text": ["So there's two major factors **You have to re-create EVERY function the original hardware had.** In the same way, pretty much 01010101110011 perfect. That's a lot of work. And the other one is **major lack of documentation**. Programmers usually don't start from scratch, there's tons of library files you can use to automatically take care of common functions & most big companies will fall all over themselves to help you (if you're a paying customer). But when you have to re-create a computer chip in software, the creators of that computer chip probably aren't jonesing to spill each and every secret."], "text_urls": [[]], "score": [3]}}, {"q_id": "83vnfo", "category": "Repost", "title": "How did Old/Ancient Cartographers Produce Fairly Accurate Maps?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dvku1k5"], "text": ["Firstly, most of old maps you see on walls, in posters and so on (e.g. those from Ortelius, Mercator, Speed and so on) or created by people who take maps and notes from \"real\" cartographers and turned them into what we now think of as the \"atlas\" (Ortelius usually credited with the publication of the \"atlas\"). Prior to these, cartographers weren't trying to share maps with \"every day folk\", they were trying to create maps with utility for navigation. This means that the really old maps are either very specific in scope, or have a bunch of shit that is made up. This leads collectors to often focus on the \"wrong stuff\" (for those in the U.S. \"California as an island\" is a topic, and many in the middle east enjoy depictions of a giant massive lake/sea in the middle of what is a dessert and so on - these were sometimes from wrong cartography and sometimes from _filling in the blanks_ from notes, or...putting something deliberately wrong as a way of finding future _copycats_ of your map (poor man's copyright so to speak!). So...what methods WERE used? Well...if you're looking at large maps (e.g. world, continent, country) typically the maps were made by triangulating coast line from a ship. Pick a known spot of coastline and then do relative position analysis and draw to scale. Wash rinse-repeat. What's important to know is that massive parts of coastline in maps for hundreds of years were really just copies of prior maps. For example, Ortelius's famous map of the Middle East is really a copy of Gastaldi's \"real work\" on the area, but then adds a ton of stuff. These methods aren't ultimately all that different then the way modern surveying works, but is _very different_ then what we do with GPS."], "text_urls": [[]], "score": [3]}}, {"q_id": "83vtoi", "category": "Repost", "title": "What's the difference between a sociopath and a psychopath?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dvkxhl7"], "text": ["This a pretty complicated question because we often think that these are technical words, when they are really _media_ or _pop psych_ words. This means that we don't _really_ have a solid anchor for what they mean - they are from outside a context that usually provides precision in word use. If you talk to someone from the context _you think_ these terms come from then you're really talking about a psychological disorder - the antisocial personality disorder. It's probably true that when people use the term psychopath and sociopath with any level of discipline (e.g. not a way to describe your ex-wife, or the kid who isn't feeling guilty for not picking you first for kickball) that the diagnostic rubric for these two words would most closely match this diagnostic label. However, I think it's safe to say that we _typically_ use \"psychopath\" to denote a person who has taken some _action_ and that the action is _violent_, or at least _very deliberate_. It has connotations with cunning, violence, criminal and so on. The word \"sociopath\" is used for people often who are more passive - they do things that others do, but without remorse. E.G. they commit crimes like theft, or they lie to friends, but...they do so without them being \"white lies\" - they do it without much care for consequence or feelings of the world around them. Further, in most connotations all psychopaths are sociopaths, but not the opposite. However, these are absolutely not technical words despite people thinking they are. This means we have no generally accepted authority to look to for a tie-breaker when differing opinions emerge on the meanings of these words. While the same disagreements exist in \"true\" diagnostic language, we generally accept that the DSM definitions are those around which we should orient our vocabulary."], "text_urls": [[]], "score": [4]}}, {"q_id": "83wlr0", "category": "Repost", "title": "Why is giving birth seemingly so much more painful for humans than any other animal?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dvl1b5s", "dvl374r", "dvlgaa1", "dvli4ld", "dvl17zc", "dvl0ud6", "dvlj586", "dvlk1g7", "dvlj9x0", "dvlgou1", "dvll0v1", "dvlgxla", "dvlfnvp", "dvlk45f", "dvlhtx3"], "text": ["We evolved a tough combination of traits: big heads to hold our overdeveloped brains, and slim, bony hips to allow us to walk upright. Those ended up being two of our biggest advantages, and those helped us advance beyond our early cave-dwelling, scavenger days.... but put them together and you're trying to push a big head through a small hole, and it causes a lot of problems.", "4 large natural low-drug births by small female here. All here are correct, but also because we can verbalise the experience. I've sat with cats, dogs and sheep and they definitely have that far away look in their eyes that I've experienced when focusing on breathing and bearing through the excruciating pain. Yes it's no fun pushing a pumpkin through a pinhole but the process leading up to that can go on for days in humans and animals and it's not exactly pain-free either.", "I'm the husband of a Doula, as well as a father of three. I'm not exactly an expert, but I've spoken to a lot of them. There's a lot to unpack with this. The folks pointing out the head / birth canal size ratio are not wrong, but that was more of an issue for earlier hominids than us modern humans. Most women have adequate space to push a baby out, some of the discomfort is actually the body moving around internal stuff and stretching around to accommodate the baby. People have very different pain tolerances. Some women start screaming at the first contraction, others can go about their daily activities for hours or even days before labor gets too intense to stand or have a conversation. Animals have almost universally evolved to hide any sort of pain, as any show of weakness in the wild can attract the attention of predators. This would be horrible to have happen during birth, most likely resulting in the death of the mother and children. Humans have not had that as a factor for many many generations (probably for tens of thousands of years, but just a guess) so the folks with little to no pain tolerance are able to reproduce without issues. So animals don't tend to show pain the way people do, and pain is subjective. The comparison isn't really apt, unless you have a way to measure the actual pain level in an animal", "Here is the real answer: When an animal gets shot, hit by a car, or attacked by a predator, they often make no noise at all - it's to assure their survival. Animals giving birth are in a lot of pain/discomfort but can't vocalize it and survive.", "Because our main evolutionary advantage over other animals is a large brain. To get that we need a large head. So there is a balance between the physiology of the female being able to give birth and the size of head possible at that time. Other animals, both baby and mother have to be able to evade predators from day one, so the young have to be relatively more developed and the mother not incapacitated by the birth process.", "Our human heads are bigger. The first is that human birth hurts. You can watch the birth of other animals and they seem to brush it off, but for humans, forcing that huge head through a relatively small birth canal is difficult.", "When my cat give birth, it was pretty damn intense. They go into this deep breathing mode and absolutely look like they're going to die. I think this is like the \"why don't animals get sick as much as humans?\" Answer is they do, you just don't see it.", "Simple answer is, I think we are just better at communicating our pain. Hyenas give birth *through their clitoris*. I think if they could talk, they'd maybe chime in.", "I've seen a cow giving birth. I'm not a vet or a farmer but it certainly didn't seem like a painless experience for the cow. She was grunting and contorting her face somewhat. The cow wasn't very loud iirc but it was definitely unpleasant for her.", "There really isn't natural selection for ease of reproduction in humans. People with narrow hips can reproduce as many times as someone with wide hips. Having multiple offspring without dying is tied to access to prenatal care rather than physiology, so easy birthing traits are not passed to the next generation with a higher rate than any other trait. Even fertility doesn't effect the average person's ability to reproduce.", "Hyenas have it pretty rough, IMHO. [The female has to push the pup out through her pseudo-penis/clitoris.]( URL_1 ) By some twist of evolutionary fate, female hyenas have more testosterone\\* than the males, hence the penis. They're bigger and meaner and dominate family groups, but most importantly, [they have to bite open or otherwise split their dicks]( URL_0 ) to pass their litters of cubs and it kills the mother or the cubs as often as not\u2020. It's just about the most intense birth process I've heard of in a mammal. Point being: I'm not sure it's fair to say that humans have it worse than other animals as any kind of general rule. edit: \\*May be androgen that causes these traits. I'm more inclined to trust the wiki than my original link. \u2020first time mothers only edit2: I've been chasing down wikipedia footnotes, and I found that hyenas birth process is so traumatic to the vulva that people though Hyenas could change sex from season to season. After puberty, females are still outwardly similar to males, but more fleshy, I guess. After pregnancy it's all messed up. [ > ...a slack walled and reduced prepuce, with an enlarged orifice and which has come to lie ventrally, and the lips of which tend to lie apart, eventually bears but a limited resemblance to a penis.]( URL_2 )", "Probably will be received with criticism, but the biblical explanation is that painful labor is a punishment to women for eating from the forbidden tree. As for an evolutionary explanation, big heads.", "Most animals scream quite a bit when giving birth. It is not a fun process. It\u2019s easier for us to perceive human pain than animal pain. It is not an enjoyable experience for them either. When that cute ass lil guffer pops out though it\u2019s worth it.", "Most of your household pets (dogs and cats) are predatory animals (or at the very least are not prey, I know dogs can be scavengers or predators). They have little to fear while giving birth and tend to give birth alone. If a baby dies, they eat it. Their babies are kind of helpless at first. Many farm animals that live in herds make noises, and if you think about in the wild...a predator might be scared off by a loud braying noise in the middle of the night. It also calls other herd animals to the mother to help her/protect her baby. Those babies can walk and run within about 15 minutes of birth. To help get away from predators. Most modern depictions of childbirth are very...non-traditional? If that's the right description. Women tend to be alone or with only a provider/partner [today]. But if you think about how women would have given birth when we were still tribal...most women gave birth with many women around her. She also would not have been restricted in her movements. Some of the sounds a mother makes can be a signal to those around her what stage of labor she is in. It's sort of a community effort...the noises can be a call for help, and a signal to drive away, too. Most women I've experienced giving birth in a more 'natural' setting tend not to be screaming and huffing and puffing. And earlier I talked about predator/prey behavior...humans can technically be both, but if they are giving birth in a group - there is more help and more protection...", "We walk up right. The pelvis adapted but this makes birth more risky. The baby has to go through the birth canal in a curved angle and not straight like other mammals. It leads to lots of complications."], "text_urls": [[], [], [], [], [], [], [], [], [], [], ["https://en.wikipedia.org/wiki/Clitoris#Spotted_hyenas", "https://africageographic.com/blog/good-bad-gory-birth-hyena-cub/", "https://archive.org/stream/carnivoresofwest00rose#page/356/mode/2up"], [], [], [], []], "score": [797, 183, 90, 23, 23, 13, 12, 8, 7, 6, 6, 5, 5, 5, 3]}}, {"q_id": "83yhc3", "category": "Repost", "title": "What is the function of a fever when we are sick, and how do anti-fever medications reduce it?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dvlh0sq"], "text": ["Fever is stimulated by a part of your brain (your hypothalamus) that is in direct contact with the bloodstream, unlike most of the brain. Certain molecules floating in the blood will trigger the fever response. These can be external things--proteins on the surface of bacteria, for example--or special signaling molecules produced by our own immune system. Once this part of the brain is triggered by these \"pyrogens\" (literally \"heat-makers\" in greek), it produces a bunch of other signaling molecules called prostaglandins that carry the signal to another close part of the brain, which actually recalibrates the body's main temperature sensors to a higher level. The increased body temperature does a few things: * It moves the body temperature outside the optimal reproductive range for many bacteria * It makes many naturally-produced antibiotic substances more chemically effective * It may make cells of your immune system more active NSAIDs, including aspirin and ibuprofen (Advil/Motrin), stop the body from producing prostaglandins, blocking the fever signal. Prostaglandins are also involved in inflammation and pain, which is why those drugs work for that. Acetaminophen/paracetamol (Tylenol) also reduces fever, but we don't actually know how, weirdly enough. It might work similarly to NSAIDs, but \u00af\\_(\u30c4)_/\u00af"], "text_urls": [[]], "score": [3]}}, {"q_id": "842qmc", "category": "Repost", "title": "Why do pigeons (and other birds) move their head back and forth on every step they take?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dvmcp19", "dvmcvxl"], "text": ["They lack the means of moving their eyes independently. Bobbing their heads with their stride keeps their vision steady", "Because their eyes are so big compared to their head that they can not move them. If you want to look to somewhere to the side, you can just move your eyes. A pigeon or a chicken has to move their entire head. When you walk and move around your eyes automatically move to make sure you keep looking at the same thing. a chicken can't do that so it has to move its entire head with every step to make sure the eyes stay pointed at the same thing. It is no that they move their head, but that they move their bodies and have their head stay fixed as much as possible. ([See this Mercedes Benz commercial for an example]( URL_0 ))"], "text_urls": [[], ["https://youtu.be/nLwML2PagbY"]], "score": [9, 8]}}, {"q_id": "843pu2", "category": "Repost", "title": "Why were pre-historic animals so much larger than our modern day ones?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dvmiblw", "dvmifh7"], "text": ["No definitative answer however, theories are the enviroment was warmer, more carbon dioxide in the atmosphere and plentiful vegetation/food allowed dinosaurs to grow large. Another theory was simply for self-defense.", "The largest animals ever known to have lived are alive today, specifically the blue whale. Additionally, our perception of the size of animals in the past is skewed. Bigger animals make better headlines, and bigger fossils are easier to find. There were *plenty* of small animals just as there are now. Now that being said, we do see a fair number of large terrestrial animals from that time. One theory for land animals in the past is that they grew in size as a sort of arms race. Prey became larger to be harder to kill for predators (just as an adult elephant has little to fear from today). Predators became larger to kill those prey, and so on. However, this is just one 'strategy' among many that may be pursued, similar to having a hard shell, producing lots of young, and so on, when it comes to evolution. So life doesn't particularly *aim* for being big, but being big might arise if it is an advantage. And it isn't always an advantage. The extinction event that wiped out non-bird dinosaurs would have quite possibly made large size become a significant disadvantage, because it disrupted food chains by diminishing photosynthesis. If you're a large animal, you need a lot of food. A sudden loss in food availability is bad. Advantage goes to smaller animals and scavengers. Large animals have existed between then and now as well, but there's a new *huge* disadvantage, and that is humans. If you are big, you need lots of space, you need lots of food, and you are potentially dangerous. Well now the world is full of humans. We divide land, we remove ecosystems, and we *really* don't like danger. So being big today means you are quite probably at odds with us, and generally speaking this is a very dangerous place to be for an animal. We have eliminated a great many large animals ourselves."], "text_urls": [[], []], "score": [3, 3]}}, {"q_id": "84548b", "category": "Repost", "title": "Why are tech and thought leaders so worried about A.I.?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dvmzeav", "dvmtu93", "dvmza2g", "dvmzcln", "dvmto3i", "dvn2c4b"], "text": ["The problem is so large that I\u2019m not sure I could boil it down to something digestible by a 5 year old. But here\u2019s the simplest I can really put it: The growth of intelligence in AI is happening on an exponential scale, not a linear scale, so by the time we get close to human level machine intelligence and stop, we may have actually stopped at a point well beyond human intelligence. Even worse, we may not even be aware of that fact at the time that we stop the growth and even think that it\u2019s only as smart as a human. To give you an idea of how bad going past human intelligence would be we can think of the intelligence of all life on earth as a graph. Picture an ant at the bottom and a human much higher on the graph. Now if you asked yourself \u201cWhere would Einstein be on this graph?\u201d You might think \u201cmuch higher than the human average!\u201d But for any graph that would fit on a sheet of paper the dot for the human average and the dot for Einstein would be indistinguishable in location. So if AI\u2019s intelligence goes beyond us on an exponential scale, you can more or less forget about trying to outsmart it. I\u2019m grossly oversimplifying this topic. If you want a decently short book that covers a lot of what paths, strategies, and dangers lie ahead of us check out Superintelligence by Nick Bostrom. He covers a huge amount of problems on this topic, anyone who\u2019s interested in becoming an AI dev should definitely give it a read.", "There are numerous ethical and social dilemmas presented by AI. 1. Increasingly intelligent automation of tasks presents new potential challenges. With AI and sufficient processing power, a government could essentially put together a complete profile of every citizen's every movement based on various data sources. This is something that seemed unfathomable even a few decades ago. 2. If we allow autonomous weapons systems does that greatly lower the danger and public pressure against warfare, does this SERVE humanity by saving lives, or does it just make it easier to kill someone from another country just because we don't put our own people in danger? What happens if a non-human-controlled weapon system malfunctions and accidentally starts attacking the wrong people? Who is responsible? 3. Self-driving cars. If a self-driving car gets in an accident and it's the fault of something software or hardware related, who should be responsible? The company that made the software? The company that made the hardware? The car manufacturer? The person in the vehicle that wasn't driving the car?", "There is a great documentary about this issue, it\u2019s called \u201cThe Terminator\u201d. It will explain everything!", "We're talk about an intelligence that could exponentially improve itself. It's not that we KNOW Ai would be hostile, WE DON'T HAVE ANY WAY OF KNOWING WHAT IT'D DO. That's kind of the whole threat, because it thinks on a level we couldn't imagine.", "The biggest issue is that any AI worth it's salt is going to be able to self program. So as it learns to code better, it will improve itself, which means it can learn faster, which means it can recode itself better, which means it can learn even faster... until it's literally the smartest thing possible on this planet. At which point we would be obsolete (or so the logic goes).", "Because they watch too many Sci-fi movies and don't even have the foggiest idea of how current machine learning techniques work. They can do some impressive things, but to get anything even approximating the kind of system necessary for a 'Rogue AI' is so far beyond the pale is just stupid."], "text_urls": [[], [], [], [], [], []], "score": [16, 14, 13, 6, 5, 4]}}, {"q_id": "845hih", "category": "Repost", "title": "Why do some countries show pricing on the shelf excluding taxes? Where I'm from it shows the final price you will pay on any advertising and pricing labels which makes sense.", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dvmwm05"], "text": ["U.S. sales taxes are VERY Complicated. We don't have a national sales tax that applies evenly across the board. Sales tax goes down to the state, county, and even local levels. The tax you pay in one store could be completely different to the tax you pay in the store across the street in extreme circumstances. Plus the types of goods that are taxed also vary (some states charge tax on groceries, others don't, for example). Having to individualize all these different price tags would be a logistical nightmare."], "text_urls": [[]], "score": [6]}}, {"q_id": "8461j1", "category": "Repost", "title": "When houses creak at night, what are those actual noises?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dvn1n0n"], "text": ["To expand on the previous answers, this happens during the day as well. You just don't realize it because you're paying attention to other things."], "text_urls": [[]], "score": [3]}}, {"q_id": "84639g", "category": "Repost", "title": "What happens to a company after it files for Bankruptcy?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dvn4qo3"], "text": ["there are 2 general kinds of business bankruptcy - liquidation and restructuring in Liquidation, your business is basically a complete failure. The court usually appoints someone to come in and shut down the business, handle all the employee exits, sell the remaining assets, etc. The company ceases to exist and any execs and board members just walk away. Some execs may continue to get paid as if they're needed in order to settle the affairs in an orderly fashion in Restructuring, the business is in bad shape but is still viable. The management of the company usually presents a plan to the court to pay off debt, sell assets, reorganize, etc and get the business back on its feet. If the court accepts the plan the management will execute it under court supervision until the bankruptcy process is complete. The execs and board members may stay or may be replaced as part of the restructuring."], "text_urls": [[]], "score": [5]}}, {"q_id": "846bml", "category": "Repost", "title": "Why is our limited supply of freshwater considered such a global issue when it's possible to desalinate sea water?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dvn37qa"], "text": ["Desalination is energy intensive, expensive, and moving it across large distances to landlocked areas is also difficult."], "text_urls": [[]], "score": [4]}}, {"q_id": "84a0ml", "category": "Repost", "title": "What is a wormhole?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dvnzkap", "dvnzwv3"], "text": ["A wormhole is like a shortcut. The best description Ive seen or heard of a wormhole was in the movie Interstellar. Imagine you have two points on a piece of notebook paper. One at the top one at the bottom. If you were to travel between points it would take a while. But if you were to fold the paper where the two points touch, you could immediately get from one point to another. Anytime Ive heard astrophysicists talk about them, they say they could be real, but would have to put somewhere by \u201csomebody\u201d. They wouldnt be naturally occurring. Blackholes are a totally different thing. They are a point in space where gravity is so strong nothing can escape. Most of what we know about them is speculation. Theyve been observed but we have no idea what lies beyond the event horizon (the moment you enter) Side note: If you haven\u2019t seen Interstellar, watch it. Its the most accurate movie when it comes to space travel, relativity, black holes etc. of course its fiction and all but every little detail in the movie was from consultations from Astrophysicists and what-not. Even the black hole in that movie is how one should theoretically look and work.", "Imagine a flat piece of paper with an ant walking on it. The only way for the ant to get from one edge of the 2 dimensional sheet to the opposite edge is to walk all the way across. But you can bend the paper across the third dimension so the two sides touch each other and now the ant can just walk across one side and instantly be at the other edge. A wormhole is effectively a bending of our 3 dimensional space across the 4th dimension to connect two separate points. As of now, they are only theoretical and we have seen no evidence of their existence."], "text_urls": [[], []], "score": [14, 3]}}, {"q_id": "84acql", "category": "Repost", "title": "Why does smoking tobacco cause cancer, but smoking marijuana does not?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dvo2cz2", "dvo2nau", "dvo5000"], "text": ["It does. It's the burning part that creates carcinogenic compounds. That's one of the major reasons that e-cigarettes are a better option (for both tobacco and marijuana). The incidence is lower with marijuana because most people smoke marijuana less frequently than tobacco.", "One thing to keep in mind is that there have been a *lot* of studies on the effect of tobacco on health. I mean, just a ton of studies. It's really one of the more studied health issues out there. Compare this to marijuana, which has until recently been illegal almost everywhere, meaning it has been difficult if not impossible to study its health effects. So even though there has been research that suggests that marijuana doesn't cause cancer, I wouldn't accept that as unequivocally true quite yet because it's definitely possible further research will show the opposite. In any case, if marijuana doesn't cause cancer, nobody really knows why quite yet. The interesting thing is that marijuana smoke *does* contain carcinogens, sometimes even more than tobacco, and marijuana smokers tend to inhale quite deeply, but for whatever reason the carcinogens in marijuana smoke don't have the same effect as the carcinogens in tobacco smoke. I've read that some people think that there is a property of THC itself that may counteract the carcinogens in the smoke. But again, research on all of this is still quite young, so who knows.", "Short answer, this is a common misconception. It contains more carcinogens than tobacco smoke, here is one of many studies on the matter URL_0"], "text_urls": [[], [], ["https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2516340/"]], "score": [9, 4, 3]}}, {"q_id": "84c5jv", "category": "Repost", "title": "how is the mass of distant stars calculated?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dvofp7w"], "text": ["There are a few common ways to determine the mass of stars. 1) For stars that are alone, by looking at how bright the star is, its colour, and its size, we can use a [Hertzsprung-Russell diagram]( URL_0 diagram) to figure out reasonably well what their masses are. 2) For especially massive or dim stars, we can use an effect called gravitational lensing to determine the star's mass. When light from behind the star passes by it, the light bends depending on how massive the star is. We measure how much the light bends and figure out the mass from there. Note that the above method is not often used because you need very sensitive equipment to get a good result since the lensing effect isn't normally very large. 3) If the star is close to another star or multiple stars with known masses, we can see how the star interacts with the other stars gravitationally and figure out the mass from there. As far as I know, number 1 is the most common method since we already have a large data set of stars used to construct that diagram and its usually reasonably accurate."], "text_urls": [["https://en.m.wikipedia.org/wiki/Hertzsprung\u2013Russell"]], "score": [6]}}, {"q_id": "84ch7b", "category": "Repost", "title": ". Why does orange juice taste so bad after brushing your teeth or eating something minty?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dvohgtq"], "text": ["Sodium Lauryl Sulfate This is the detergent part of the toothpaste, the stuff that makes most of the lather when you brush (it shows up in shampoo for the same reason). It has a strange side effect, though: It desensitizes the taste buds that register sweetness. That's why orange juice tastes so awful right after you brush your teeth \u2014 your tongue is picking up only the sour and bitter flavors. As the amount in your mouth diminishes after brushing, your taste buds return to normal. (From URL_0 )"], "text_urls": [["https://www.wired.com/2007/09/st-colgate/"]], "score": [7]}}, {"q_id": "84d14z", "category": "Repost", "title": "What's the difference between multi-level marketing and pyramid schemes?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dvojozy", "dvondfz", "dvoo872"], "text": ["In a pyramid scheme, the only way to make money is by bringing in new participants. Multi-level marketing has, at least theoretically, an actual product or service you can sell in order to make money. In practice, many MLM companies offer worthless product which are nearly impossible to actually make money from, which makes them no better than pyramid schemes. Other MLM companies are completely valid and have been operating for decades.", "MLM calls themselves that because they don't want the negative connotations of \"pyramid scheme.\" But.... when they're both triangles, the difference is one of semantics.", "I have been in MLMs for 3 years. If you want the honest truth. There is no difference, NONE. Dont waste your life like I did."], "text_urls": [[], [], []], "score": [7, 5, 4]}}, {"q_id": "84dw77", "category": "Repost", "title": "What is Grey matter of our brain?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dvoq9wn"], "text": ["The cell bodies of neurons. The white matter is the axons (or the thread like parts they use to communicate), and is covered in myelin, a protein which is white. Myelin helps get the messages along faster. Because the cell bodies aren't really transmitting messages long distance (they just create them) they don't need myelin and thus appear grey. Grey matter is on the outside of the brain, white matter on the inside"], "text_urls": [[]], "score": [8]}}, {"q_id": "84e3vq", "category": "Repost", "title": "Why does a group of people singing sound better than an individual singing ?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dvot4dd"], "text": ["Because it smooths out the imperfections. One person might sing one note slightly out of pitch or out of tempo, but when you average it among 1000 people it sounds more \"perfect\". That's why you'll even have pop singers do muti-layering over their own voice for choruses to give it that same feeling. Also in a musical piece such as a Mass or Opera, you can have different voices singing different notes at the same time to allow for harmonic chords that sound more interesting than single notes."], "text_urls": [[]], "score": [7]}}, {"q_id": "84j06f", "category": "Repost", "title": "How do you add color to black and white photos from say the early 20th century?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dvpxq7r"], "text": ["A black and white photograph captures the shading of pictures objects but does not retain any color information. The color chosen therefore is arbitrary, a guess based on what makes the most sense. People should be some kind of flesh tone, leaves should be green, the sky should be blue, but what color are their clothes? That is purely up to the imagination of whoever is adding the color. Some research can be done to determine what color such things are likely to be of course, but it is a later addition to the photograph rather than something which is extracted from it."], "text_urls": [[]], "score": [7]}}, {"q_id": "84j8cs", "category": "Repost", "title": "How come when you speed up sound it comes out really squeaky, but when you slow it down, it sounds very deep?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dvq00w2", "dvq0jmp", "dvq4jgu", "dvq0h7n", "dvq3lxb", "dvq4p8z"], "text": ["Sounds are vibrations. The faster the vibration, the higher the pitch. (And the larger the vibration the louder the noise). So speeding it up increases the vibration rate making a higher pitch and slowing it down decreases the vibration, lowing the pitch.", "Every persons natural sound is a combination of one fundamental frequency, with a mess of harmonic frequencies that add to the timbre of their voice, but don\u2019t define the note as it would be picked up by a guitar tuner. That note is all fundamental frequency. The note is also just an ugly sine wave, and the frequency of that sine wave (which has the fundamental frequency) is measured by how many times the sine wave goes up and down every second. People with very high voices have sine waves that go up and down more times every second than people with very low voices. Let\u2019s say you sing lalalalalalala, and that takes you 2 seconds. Welp, if you speed that up, and it only takes 1 second for the full string of \u2018la\u2019s to finish, then you had to have made all of the ups and downs happen in half the time. Now you have the same number of ups and downs in half the time, so the frequency of the speeded up version is doubled for every second that the sound goes on. Since higher frequencies sound higher to our ears, we hear that as a Mickey Mouse voice. The reverse is true for slowwwed dowwwwn versions of the original Lalalalala. Edit: phones", "It's all about frequencies(occurrences per second in the case of sound waves). Every sound you hear(between about 20-20,000 cycles per second, or Hertz) travels through the air as a wave. As the frequency(Hz) of something increases, it's perceived as in increase in pitch. The threshold of human hearing is roughly 20Hz-20,000Hz. So any sound wave that travels through air fewer than 20 times/second, will almost certainly be too low of a frequency for your ear to perceive, same for anything above 20,000, it'll be too high to hear(think of the \"silent\" dog whistles).", "Low sounds are made by low frequencies, high sounds are made by high frequencies. Imagine you're in a boat floating on the ocean. There are waves coming at a consistent rate, and you're bobbing up and down with them. You turn on your motor, and speed into the oncoming waves. Now you're bobbing up and down faster and faster because from your perspective, the waves are coming faster and faster. This is like speeding up sound. The waves come faster and faster, so you get a higher frequency. If you turn your boat around and start going in the same direction as the waves, you start bobbing slower and slower, which is like slowing down the sound, giving a lower frequency and lower pitch. If you go at the same speed as the waves, you don't bob at all.", "Higher pitched sounds have waves that are closer together, and lower pitched farther apart. When you manipulate the speed of a recording you're literally changing those waves to be closer together or farther apart, thus making it higher or lower pitched.", "The same reason why an approaching car sounds different from when it passes and starts to move away. Sound is a wave and the crescents of those waves hit our ears at certain frequencies. We perceive higher frequency waves as higher pitch. When you speed up sound, it gets send out at a higher frequency, hence the chipmunk speak."], "text_urls": [[], [], [], [], [], []], "score": [266, 83, 5, 4, 3, 3]}}, {"q_id": "84j8vq", "category": "Repost", "title": "What even is wind?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dvpzq0j", "dvq0pnn"], "text": ["Wind is the uneven heating of the Earth's surface. Some parts heat up, the air expands and rises. Other air rushes in to replace it.", "Hot air rises, cold air sinks. Wind is lateral movement of this air as it struggles to find its place in the world."], "text_urls": [[], []], "score": [46, 10]}}, {"q_id": "84jmio", "category": "Repost", "title": "Fourth Dimension", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dvq38z6", "dvq4zof"], "text": ["Note that a dimension is just another value needed to define something's \"location\". So consider time as the 4th dimension. Can you define something in the world with only 3 values? Well, to some extent, yes. You can say that right now you're at 50 x, 78 y, 10 z according to some arbitrary axis. Let's say that's your bedroom. But are you always in the bedroom? No, of course not (hopefully). People go out and do things. So you need 3 spatial coordinates *and* the time to define where something is in our world. I'm at my bedroom doesn't fully capture me. I'm at my bedroom at 7:00 am *does* fully capture me, though.", "If you are talking about for spacial dimension, stuff like the tesseract (which is a 4D version of the cube). If you are talking about time, u/flyingjam has you covered. Let's start off with what a dimension even is. and What 1D, 2D, and 3D are. A dimension just tells you the numbers of values I need to find something. One dimensional space, that's just a line. Like a ruler. You can tell me how long something is, that's one dimension. If I had a ruler and you told me to take a marker and mark 50 cm spot, I could do that. no more information needed. Two-dimensional space, that's a piece of paper. If you want to be draw a dot somewhere on that piece of paper. You need to tell me two dimensions. If we say the top right corner is zero (fun fact: your zero point is whatever you want, we just have to agree on it). And you say \"Draw a dot 10 cm to the left and 1 cm down\" I can do that. But if you told me \"draw a dot 10 cm to the left\" I could draw that 1 cm down, 5 cm down, 20 cm. I wouldn't know what you want. Now, the real world. That's 3D space. If you want me to go to a specific point, you will need to tell me 3 numbers. So whats 4D space? Well, space where you would need to give me four numbers for me to find a given location. That's basically it. Now for the best part, you will *never* be able to understand that it will always confuse you. I can't explain what that is like without a bunch of math. Because that's all fourth dimension is, a math concept. Mathematically we can explain it (which isn't ELI5), and we can model it. But it will never be something that you can understand intuitively. Your brain isn't able to do that."], "text_urls": [[], []], "score": [5, 3]}}, {"q_id": "84knvl", "category": "Repost", "title": "Why do you drift off when engaging in some activity but can't fall asleep when you decide to go to bed?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dvqe5ue", "dvqfbi8"], "text": ["The act of going to bed (washing, brushing teeth, changing clothes) gets your circulation going again and thus, you feel more awake.", "I think falling asleep is harder when your brain isn't engaged mindlessly. You're just laying there with your thoughts. I'm terrible because I scroll through social media while laying in bed until I get sleepy again."], "text_urls": [[], []], "score": [10, 5]}}, {"q_id": "84pp63", "category": "Repost", "title": "How can 2 switches wired to the same light be able to turn it on and off no matter the state of the other switch?", "title_urls": {"url": []}, "selftext": "There is this light along my stairs which can be affected by both switches without intervention. (AKA no \"OR\" gates) How is this possible?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dvrcu5i"], "text": ["In household electric wiring, a three-way switch setup (common term) often involves wiring two double-pole switches a line, with the power source connected to one and the lamp connected to each other. In this case, each switch has two positions, and the circuit can be completed [or broken] by moving by moving either switch to a position that completes the circuit (or breaks it), as the current can flow from either position of the first switch. [This picture is worth a lot of words ]( URL_0 )"], "text_urls": [["https://upload.wikimedia.org/wikipedia/commons/thumb/d/d0/3-way_switches_position_2.svg/300px-3-way_switches_position_2.svg.png"]], "score": [35]}}, {"q_id": "84t7g6", "category": "Repost", "title": "How does the body generate heat?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dvs9u62", "dvs9vd1"], "text": ["When we eat food, we ultimately turn it into a chemical called ATP which is carried to all of our cells and provides power for all the processes of life. When the ATP is used up, its a chemical reaction that creates heat, like burning fuel in a fire. That heat diffuses out through the body, and we can regulate how much heat is lost through the skin to a certain extent by changing how much blood flows near the surface, which is why you go red when hot and blue when cold - there is more or less blood just under your skin. If we get too cold, we need to generate some more heat, so we need to burn a bit more ATP. We can't really turn the rates of most of our cells up without bad consequences, but what we can do is flex muscle fibre. Since wildly flailing tends to attract unwelcome attention from predators, we want to flex muscles a really small amount, very often, which is why we shiver.", "There are constant and numerous chemical reactions going on in our bodies such as digesting food, synthesizing proteins from basic amino acids, making ATP from oxygen and glucose in every single cell, using that ATP for energy, etc. Most of these reactions are exothermic, generating heat as a by-product. The rate at which many of these biochemical reactions occur is also influenced by internal temperature, which is why your body tries to keep a stable temperature. If you get too cold your body will increase the rate of internal heat-generating reactions as well as urging you to get yourself into a warmer environment. Too hot, and you start to sweat since water evaporating from your skin has a cooling effect."], "text_urls": [[], []], "score": [5, 3]}}, {"q_id": "84v154", "category": "Repost", "title": "Why does glass look green/ opaque if you look at it through its edge? Why does occur when multiple panes of glass overlap too?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dvskyac"], "text": ["Glass is green, ever so slightly. Vsauce did something similar with mirrors which green shifted light as it got reflected over and over. The more glass the light goes through the greener it becomes"], "text_urls": [[]], "score": [13]}}, {"q_id": "84vk82", "category": "Repost", "title": "Why do soft baked goods go hard when they get stale, and hard baked goods go soft when they're stale?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dvsnqux", "dvsu5ul", "dvtet6m", "dvt6gzm", "dvt6qxh", "dvt6xke", "dvt4v6p", "dvt8sv3", "dvu9s1z"], "text": ["Harder baked goods absorb moisture over time because they start out dry compared to the moisture in the air and become softer as a result. Softer baked goods that already have moisture in them which is used chemically to make their gel-like structure instead lose moisture over time (since there's less moisture in the air than in them). This makes them harder.", "Yer not alone in askin', and kind strangers have explained: 1. [ELI5: How come a soft cookie becomes hard when it is stale while a hard cookie gets soft? ]( URL_2 ) ^(_39 comments_) 1. [ELI5 why stale bread is hard and stale crackers are soft. ]( URL_1 ) ^(_2 comments_) 1. [ELI5: Why do hard/crunchy foods turn soft and soft foods turn hard when stale? ]( URL_5 ) ^(_6 comments_) 1. [ELI5: Why do cookies go soft when stale and Bread go hard? ]( URL_6 ) ^(_6 comments_) 1. [ELI5: Why does soft food get hard when going stale, and hard food get soft? ]( URL_4 ) ^(_6 comments_) 1. [ELI5: Why do certain foods (like cookies) go soft when they've been in the cupboard a while, but other foods like bread become hard? ]( URL_3 ) ^(_6 comments_) 1. [ELI5: Why do some things get softer when they're stale (i.e. Oreos) but others get harder (i.e. chips). ]( URL_0 ) ^(_7 comments_)", "There are two things going on: 1) Dehydration/re-hydration 2) starch retrogradation First, let me address dehydration/re-hydration. Soft baked items such as cake and cookies often contain egg, and are baked until the egg proteins set, but are not baked until all the water content escapes. The baking also activates the chemical leavening, puffing them up. (Cakes and cookies are not typically yeast-leavened; they typically use baking soda or baking powder, which release CO2 as they are heated and/or moistened.) As they \"go stale\", they lose water content, leaving the egg protein and starch matrix hard and dry. Hard-baked items like matzos, fillo dough, and other such things are baked to dehydrate them well past the level of ambient moisture. They pick up moisture, and get soft. (Or, to be more precise, lose their crispiness; they don't really ever go totally soft again.) Secondly, \"staleness\" also involves starch retrogradation. Starch is not in its lowest energy state when it is cooked; a portion of it will revert to the uncooked state given the passage of time because it is energetically favorable. This reversion to the uncooked or less-cooked state is what constitutes some of the texture of \"staleness\" in baked goods. Retrograded starch is harder than the soft-cooked stuff, but softer than the hard-cooked stuff. Retrogradation can be reversed to a large extent by just re-heating the baked goods.", "Because all objects move towards an Environmental moisture equilibrium. Same thing with temperature.", "They're both trying to attain equilibrium with their surroundings. Really dry stuff (baked & fried items) will grab moisture from the air, wet stuff puts moisture into the air unless the humidity is high", "Follow up question: Why doesn't sour cream turn sweet if sweet cream sours?", "Because their moisture content is tending towards the moisture content in the air. So very dry will become less dry, very moist will become less moist.", "Think of it like having a glass of cold water and a glass of hot water. One is starting cold and one is starting hot. As they sit the heat or cold is slowly moved closer to room temperature. It's essentially the same with soft/hard baked goods. As they sit they want to move to a state of not too hard or not too soft \"room-tempature\".", "Life consists of great polarities, i.e. positives and negatives on a balance scale that are magically attracted to each other. This applies to virtually everything in existence from the macro world to the micro world including cold/heat, darkness/lightness, masculine/feminine, order/chaos, down to the interaction of subatomic particles, and even, yes you guessed it: moisture and dryness. Items that are dry will naturally absorb moisture, and items that are moist will naturally dispense their wetness into drier air."], "text_urls": [[], ["https://www.reddit.com/r/explainlikeimfive/comments/4akmk0/eli5_why_do_some_things_get_softer_when_theyre/", "https://www.reddit.com/r/explainlikeimfive/comments/30ja5l/eli5_why_stale_bread_is_hard_and_stale_crackers/", "https://www.reddit.com/r/explainlikeimfive/comments/41ii94/eli5_how_come_a_soft_cookie_becomes_hard_when_it/", "https://www.reddit.com/r/explainlikeimfive/comments/5n60sd/eli5_why_do_certain_foods_like_cookies_go_soft/", "https://www.reddit.com/r/explainlikeimfive/comments/5opq7d/eli5_why_does_soft_food_get_hard_when_going_stale/", "https://www.reddit.com/r/explainlikeimfive/comments/6jps9s/eli5_why_do_hardcrunchy_foods_turn_soft_and_soft/", "https://www.reddit.com/r/explainlikeimfive/comments/1x27lo/eli5_why_do_cookies_go_soft_when_stale_and_bread/"], [], [], [], [], [], [], []], "score": [7285, 158, 46, 12, 9, 5, 4, 3, 3]}}, {"q_id": "850xfq", "category": "Repost", "title": "Why does the current go in the opposite direction as the flow of electrons?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dvtxffi", "dvtwwuz"], "text": ["The sole reason for this is that the flow of electrical current was discovered long before the proton was given its positive charge and the electron its negative charge. It's an unfortunate historical accident that really has no consequences outside of learning about electromagnetics and circuits for the first time. Every electrical and computer engineer simply keeps it in the back of their mind.", "The convention was established many years before the discovery of the electron. > is the current not going from the battery to the lightbulb The current in a simple series circuit always flows in a loop. It goes to and from the lightbulb. The only thing that conventional current flow establishes that's different from electron flow is the sign (+or-) of the measurement. The concept of conventional current flow is just as valid as electron flow. The absence of an electron is called a hole and hole flow=current flow. URL_0"], "text_urls": [[], ["http://mste.illinois.edu/users/Murphy/HoleFlow/HoleFlow.php"]], "score": [3, 3]}}, {"q_id": "850xqy", "category": "Repost", "title": "Why does turning something off and on again fix the problem?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dvtymlh"], "text": ["In short, it's because you're returning it to a known good state. When you reboot, all the initialisation routines run in the correct order, various start up tests get everything where it should be, so you can carry on from a properly set up environment. Why do things get into a state where that's necessary? Perhaps some software is poorly written and keeps on assigning new memory locations instead of reusing old ones... so it slowly eats up all of the memory in the computer until it runs out of space to do even basic housekeeping, and chokes (this is called a \"memory leak\". In a physical system of valves or relays or whatever some glitch could get the system into a state that hasn't been anticipated, so parts behave out of sequence erratically, and a reinitialisation gets everything back in place and sync."], "text_urls": [[]], "score": [8]}}, {"q_id": "853fz1", "category": "Repost", "title": "why do you get tired after sleeping alot", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dvuipsn", "dvujair", "dvuigkq", "dvuj47h"], "text": ["Mostly it's that your blood pressure is low, you're dehydrated, and your blood sugar has been low for a while. There may be a more complex hormonal interaction behind it, as well. Drink a liter of water, eat a light snack, and do some stretches and squats.", "Your brain releases melatonin every evening depending on your sleep cycle. So you feel sleepy , tired and tend to get rest. When it\u2019s time to wake up, the melatonin level reduces and you are all set to start your day with higher vital signs and blood pressure. But if you stay inactive/over sleep, you disturb the melatonin cycle and the body gets confused about whether it needs to rest or not. Your body says it\u2019s doesn\u2019t need melatonin but the brain thinks it does. So there is an irregularity. In this case you feel tired yet not sleepy. Basically it\u2019s all about the melatonin release rhythm.", "It's best to wake in-between deep sleep cycles rather than in the middle of one. Waking in the middle of REM can lead you to feeling groggy during the day. If you wake during non-REM you're more likely to feel alert and attentive as the day progresses.", "From what I remember from school, there are chemicals released in your brain while you sleep, and oversleeping can result in more of that being present. Because of that, your brain becomes \u201csoggy\u201d for lack of a better term, which makes you feel tired or groggy instead of refreshed and awake."], "text_urls": [[], [], [], []], "score": [772, 96, 34, 23]}}, {"q_id": "853y9l", "category": "Repost", "title": "What does \u201cmeta\u201d mean?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dvuiooi", "dvuifve", "dvuifgu"], "text": ["It has two meanings which come from two different places 1) META in gaming usually refers to \"Most Effective Tactic Available\" - as in, which way to play is most popular and strongest, which hero, items, weapons & whatnot are played, or the tactics/strategy which are employed. So, lets say, \"Current Meta is playing highly aggresive tactics, because recently their main counters have been nerfed/weakened.\" 2) Meta in the... not-gaming sense means \"self-reference\". Meta-movie is movie about movies. About making them, how they work, & so on. Or maybe the characters are aware they are in a movie (Deadpool), which makes them *meta*. Or you play a game, where the character is dealing with the fact that he is just game character. Where a topic deals with itself & references material which is used to make/use it. Also 4th wall breaking is not always *meta*, but very often they go hand in hand. 3) Also there is \"meta\" which should mean \"beyond\", such as \"metaphysics\" but this one i know zilch about. (edit: 2 & 3 might come from the same term, but i personally cannot explain what metaphysics and similar meta-items are about)", "Meta is anything that is self-referential. Picture a mirror that's looking into a mirror and commenting on how deep he is. The, \"oh self reference is witty and deep\" is a part of what meta is.", "For video games: META (Meta) means \"Most Efficient Tactics Available\" - basically, the most optimal build or skill set up to do the most damage, or healing, or whatever. For instance, let's say a game lets you choose a sword or a bow - they are both supposed to be for damage, but the sword does twice as much damage, making the bow not viable. The \"meta\" for the game would revolve around the sword and its skills. For philosophy: It's short for metaphysical (or metaphysics): URL_0 . People say something is \"meta\" about self-aware realizations or observations of something from... within that thing, if that makes sense. For instance, a video game where you are supposed to play video games."], "text_urls": [[], [], ["https://en.wikipedia.org/wiki/Metaphysics"]], "score": [11, 7, 3]}}, {"q_id": "854wp6", "category": "Repost", "title": "How do eyelashes know when to stop growing?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dvupl71"], "text": ["They don't. Eyelashes grow continuously just like any other hair. The longer they get though, the more they get worn down regularly from rubbing against other objects. They also have a higher and higher chance of falling out the older they are. This is the same cycle that all hair goes through. All this combined leads to a certain length ending up as the average/common length of your eyelashes. If you looked closely enough, you'd be able to see that you have some eyelashes super new and short that have just started growing where an older one fell out. You just don't notice those few along the many longer ones normally."], "text_urls": [[]], "score": [3]}}, {"q_id": "8552zo", "category": "Repost", "title": "Why does pushing the button harder on a remote control with low batteries sometimes make it work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dvusmtr", "dvv0gck"], "text": ["It might not be the hardness of the press, but might be the duration of the press, as the weaker signal is transmitted longer so has a better chance of being received.", "Same reason traffic lights change earlier when you creep forward, and elevators (and pedestrian crossing signals) appear faster when you keep mashing the button. Same reason. It doesn't work like that."], "text_urls": [[], []], "score": [24, 3]}}, {"q_id": "856k4t", "category": "Repost", "title": "Do stop lights at an intersection actually have sensors if so how do they work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dvv2ayj", "dvv2c0y"], "text": ["Many though not all do. Generally it is a metal or mass detector embedded in the pavement. Often these aren\u2019t sensitive enough to be triggered by motorcycles or bikes. That can be very annoying. Usually you can tell when they have sensors by looking at the pavement. They will have cuts in the pavement the shape of a rectangle whose corners have been clipped off.", "Stop lights are either on a time clock or have intersection sensors. Sensors used to be under the asphalt and is why you see boxes cut into the pavement. The under-pavement sensors are susceptible to damage and repair is difficult. Now there are cameras next to the traffic light which look for car(s) in the lane. Life Tip: some traffic signals on regular emergency vehicle routes are set up to watch for flashing lights of the emergency vehicles. If you flash your high beams you can often trigger them."], "text_urls": [[], []], "score": [7, 3]}}, {"q_id": "85dw6h", "category": "Repost", "title": "Why are there no stars in photos of Earth from space?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dvwo7kb", "dvwoi6d", "dvwp63o"], "text": ["To put simply: light pollution. The earth is so bright in those photos that in order for the camera to have a high enough exposure to see stars, the earth would be overexposed.", "Its all about relative brightness You set a camera(or your eyeball) to let in the right amount of light so you can see the target and make sense of details on it without it getting completely washed out. If a picture is taken of Earth or a planet or any other close object, that object is generally significantly brighter than the stars in the background. In order to get a picture of Earth as Earth and not just a blinding white disc, we take a short exposure that lets in a limited amount of light, but that short exposure is too short for the faint stars to show up, they don't create a signal stronger than the sensor noise in that short exposure. If you're in a room and someone has a flood light pointed at you then you aren't going to be able to see the guys standing beside the floodlight holding tiny candles, the difference in brightness is just too extreme, your eyes have closed up to reduce the light coming in. If you're in a dark field and there are a dozen people holding candles you can clearly see them because there is good contrast and your eyes are open wide so you can see faint light.", "Another way to explain this to yourself, or your friend, is to go outside at night and take a picture focused on the light of a Street Lamp. The light from the lamp will disallow your camera to capture any light from behind the source (Stars, the moon, etc...) and then take a picture of the empty space a few feet beside the Street Lamp and you can see more so of the stars in the sky (given the light pollution around you isn't too heavy. Hope this helps!"], "text_urls": [[], [], []], "score": [5, 4, 3]}}, {"q_id": "85hs3f", "category": "Repost", "title": "Why does concrete appear to be darker in colour when there is water on it?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dvxkfyh"], "text": ["Bare concrete is textured and does a better job of diffusing light in a multitude of directions. Water creates an even surface over the concrete and only reflects light in a directional manner, like a mirror. The Mythbusters did an experiment to see if they could get sunlight into a dark interior space using a series of mirrors, but they discovered that they got better results by diffusing the light off of Jaime's plain white shirt. A similar effect can occur with aircraft radars called 'arctic reversal'. Normally, a textured ground surface produces a stronger radar return than a body of water. But in the arctic, water freezes into jagged ice while snow collects and smooths out ground surfaces. The jagged sea produces a better radar return than the smooth snow, a *reversal* of the normal radar picture."], "text_urls": [[]], "score": [5]}}, {"q_id": "85k5ct", "category": "Repost", "title": "Why do all gas stations in the USA the report the price of gas with 9/10 of the cent at the end?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dvxyl4w"], "text": ["Because the gas station is literally charging you 9/10 of a penny. So if the price is 1.99, you are basically paying $2 per gallon."], "text_urls": [[]], "score": [6]}}, {"q_id": "85nq9i", "category": "Repost", "title": "Why are wet things more transparent?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dvysuls"], "text": ["Paper items like toilet paper and paper towels have mineral fillers between their cellulose fibers, which are arranged in a lattice. Paper is translucent when wet because of a concept called the [index of refraction]( URL_0 ) which compares how fast light travels through different mediums. When the paper is dry and surrounded by air, the difference in refractive indexes of the paper vs. air is larger than the difference between the paper vs. water. Since the index of refractions of paper and water are closer to one another, the item appears to more transparent when wet than dry."], "text_urls": [["https://upload.wikimedia.org/wikipedia/commons/8/85/Refraction_photo.png"]], "score": [13]}}, {"q_id": "85oe30", "category": "Repost", "title": "Why does salt harm slugs and snails?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dvyzpyz", "dvyzj7i"], "text": ["Slugs and snails have thinner skin than we do. Their skin is so thin that water can pass right through it, but not so thin that salt can enter or exit. This is called a semi-permeable membrane: some things can pass through, or permeate, the skin (membrane), while other things cannot. When a snail touches salt, the environment is saltier outside of the snail than inside of the snail. The water inside the snail wants to be just as salty as the water outside of the snail, but because of its semi-permeable membrane, salt cannot enter the snail through its skin. Instead, the salty solution of salt and slime outside the snail pulls water out of the snail until the outside and the inside reach the same saltiness. If there is enough salt, it will draw so much water out of the snail that it dies.", "It would harm frogs too. Slugs and snails are mollusks and need to keep their skin wet because they don't have a dead layer (keratin) covering them. Think of a toad versus a frog. When you add salt to their skin it creates an imbalance - the salt will, much like a dry sponge, draw the water right out of the slug who has no defenses against such a concentrated onslaught. The slug literally dehydrates right in front of your eyes."], "text_urls": [[], []], "score": [17, 3]}}, {"q_id": "85qc14", "category": "Repost", "title": "How does a motherboard function / how does it power the cpu and gpu?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dvzccyo"], "text": ["More than anything the motherboard just connects the various components together. When the GPU or CPU do work with data they get it from the hard drive and store it in the ram when they're still working with it. The motherboard provides a way for this data to travel around your computer. It also provides low levels of power to basic expansion cards and usb ports, as well as the main power for the CPU which it gets from the power supply."], "text_urls": [[]], "score": [5]}}, {"q_id": "85tcu1", "category": "Repost", "title": "Why is our stomach \"in knots\" when we are stressed out or worried?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dw03ix3"], "text": ["There are several things. Your guts is has the [vagus nerve]( URL_0 ) going from your brain to your guts. Therefore, some psychological issues can affect your digestive system. Like a headache can cause vomiting (it's not the only cause of vomiting, however). The other thing is the [sympathetic nervous sytem]( URL_1 ). The sympathetic nervous system is responsible for fight-or-flight response, which causes changes in your guts to facilitate your ability to fight or run. When you're stressed or worried, you're at a heightened state of mind (you're in the fight-or-flight mode), therefore, your sympathetic system is active."], "text_urls": [["https://en.wikipedia.org/wiki/Vagus_nerve", "https://en.wikipedia.org/wiki/Sympathetic_nervous_system"]], "score": [3]}}, {"q_id": "85umyo", "category": "Repost", "title": "What makes a degree from MIT or Harvard different from the same degree at any other college?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dw07a98", "dw0axeu", "dw062om", "dw08fwj"], "text": ["You get to network with other people who went to Harvard and MIT. College is not about what you learn, it's about who you meet.", "I did not go to harvard or MIT. I went to a state school for my undergrad and to a prestigious private university for grad school. Two things, in my experience. First off - if you pay for a prestigious private school, you pay for *service*, *support*, and *access*. Harvard does not make a point of expelling students. Harvard wants every student to succeed and every student to graduate, and they will go out of their way to support students. You get better access to professors who care about teaching (state school profs are focused on research, and often hand teaching off to their grad students). You get better access to tutoring, mental health support, academic advising/counseling, and job support. And if things go wrong, you get the benefit of the doubt. You are treated like an important fish in a small, supportive pond. And that's all while you're *in school*. The other thing you get is a *network*. I am in touch with the majority of the professors I had and the people I went to grad school with, even the ones who work in different fields than I do. And if I needed a favor, or an introduction, an \"in\", a heads up, a letter of recommendation, I could pick up the phone and get one. My undergraduate school? Hell, the professor I interned for likely wouldn't recognize me, because I only met him once and spent the rest of the time working for his grad students.", "I've searched tha seven seas fer an answer. Yer not alone in askin', and kind strangers have explained: 1. [What makes universities like Harvard and Stanford so prestigious in the education they provide? I can't imagine that the courses they offer are that much different than other colleges. ]( URL_1 ) ^(_._) 1. [Is there a significant higher level of difficulty of learning education and obtaining a degree at the very best schools (Harvard, Stanford, MIT...) compared to other lower but respectable flagship schools? ]( URL_4 ) ^(_8 comments_) 1. [Are classes at Ivy League schools harder than at other universities? ]( URL_3 ) ^(_11 comments_) 1. [ELI5: How is a degree from a place like Harvard or Yale any different from a degree in the same subject from somewhere else? ]( URL_5 ) ^(_ > 100 comments_) 1. [ELI5:Why are universities such as Harvard and Oxford so prestigious, yet most Asian countries value education far higher than most western countries? Shouldn't the Asian Universities be more prestigious? ]( URL_2 ) ^(_._) 1. [ELI5: What makes graduating from one University better than graduating from another when they have access the same information? ]( URL_0 ) ^(_60 comments_) 1. [Is it really hard to get in universities like Harvard, Oxford, Cambridge etc.? ]( URL_6 ) ^(_12 comments_)", "You can learn to be a cook from a world class chef with several Michelin stars, or you can learn from Billy-Bob who cooks at the local truck stop. It's both cooking, shouldn't the results be the same? Top universities are top universities because they can attract the best people in their fields. Their student can then claim to have learned from the best."], "text_urls": [[], [], ["https://www.reddit.com/r/explainlikeimfive/comments/6kx69a/eli5_what_makes_graduating_from_one_university/", "https://www.reddit.com/r/NoStupidQuestions/comments/4l25xk/what_makes_universities_like_harvard_and_stanford/", "https://www.reddit.com/r/explainlikeimfive/comments/3a0mw9/eli5why_are_universities_such_as_harvard_and/", "https://www.reddit.com/r/NoStupidQuestions/comments/58lg2d/are_classes_at_ivy_league_schools_harder_than_at/", "https://www.reddit.com/r/NoStupidQuestions/comments/3a6yhd/is_there_a_significant_higher_level_of_difficulty/", "https://www.reddit.com/r/explainlikeimfive/comments/37bjyv/eli5_how_is_a_degree_from_a_place_like_harvard_or/", "https://www.reddit.com/r/NoStupidQuestions/comments/3pn4p6/is_it_really_hard_to_get_in_universities_like/"], []], "score": [39, 37, 9, 7]}}, {"q_id": "85zhm1", "category": "Repost", "title": "Does every car in existence have a different key and how do manufacturers make sure keys are not duplicated ?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dw19hng", "dw19j7z", "dw19cwn"], "text": ["They do use duplicate keys. I was with a friend when his dad unlocked and started someone else's car (same colour and it was parked a few spots away) before realizing what had happened. Turns out the actual owner of that car saw us getting in and was understandably freaking out and came running over to her car screaming and pounding on the windows thinking it was being stolen.", "Simply put, they are duplicated. That goes for really any key. However there are enough combinations that it's virtually impossible to find a twin lock that your key will work in. If you own a 1997 Honda Accord, and tried your key in every other 1997 Honda Accord you came across, you'd eventually find one that you can open and maybe even start. Years ago I remember a news story where a lady accidentally drove off in another person's car because it was the same make, model, and color, it was parked near her car, and her key just happened to fit it. That was a one-in-a-billion fluke, though.", "No, they are not completely unique, there are just a great many varieties. Yo ho ho! Yer not alone in askin', and kind strangers have explained: 1. [Do all cars have different keys? ]( URL_6 ) ^(_9 comments_) 1. [How many unique keys are there in the world? ]( URL_3 ) ^(_3 comments_) 1. [If locks are supposed to have a unique key for each one, how do master keys work for multiple locks? ]( URL_8 ) ^(_2 comments_) 1. [ELI5: How do padlock companies make so many locks, yet ensure that your key only opens your lock? ]( URL_0 ) ^(_43 comments_) 1. [ELI5: if every lock is unique and requires a different key to open in, how does a skeleton key open any lock? ]( URL_2 ) ^(_6 comments_) 1. [ELI5: Why can't my car key open other cars of the same make/model? What's different about my key. ]( URL_1 ) ^(_10 comments_) 1. [How are all keys different? ]( URL_7 ) ^(_10 comments_) 1. [ELI5: is every house key completely unique? How is this done? ]( URL_4 ) ^(_11 comments_) 1. [ELI5: How are locks/keys made so that no other key works in any other lock? ]( URL_5 ) ^(_8 comments_)"], "text_urls": [[], [], ["https://www.reddit.com/r/explainlikeimfive/comments/2j3gpc/eli5_how_do_padlock_companies_make_so_many_locks/", "https://www.reddit.com/r/explainlikeimfive/comments/2hw8b3/eli5_why_cant_my_car_key_open_other_cars_of_the/", "https://www.reddit.com/r/explainlikeimfive/comments/3omzyv/eli5_if_every_lock_is_unique_and_requires_a/", "https://www.reddit.com/r/NoStupidQuestions/comments/505vl9/how_many_unique_keys_are_there_in_the_world/", "https://www.reddit.com/r/explainlikeimfive/comments/2rzqx3/eli5_is_every_house_key_completely_unique_how_is/", "https://www.reddit.com/r/explainlikeimfive/comments/4rtx5c/eli5_how_are_lockskeys_made_so_that_no_other_key/", "https://www.reddit.com/r/NoStupidQuestions/comments/6ieeab/do_all_cars_have_different_keys/", "https://www.reddit.com/r/NoStupidQuestions/comments/7nbtga/how_are_all_keys_different/", "https://www.reddit.com/r/NoStupidQuestions/comments/37szim/if_locks_are_supposed_to_have_a_unique_key_for/"]], "score": [7, 5, 3]}}, {"q_id": "861axp", "category": "Repost", "title": "how does sunscreen work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dw1l1s9"], "text": ["So, you have the sun. The sun makes a whole bunch of radiation but most of it is blocked by the ozone layer, like a big window for our planet. The problem? There's a type of radiation called Ultra Violet radiation, which moves so fast up and down and has so much energy that some of it gets through and penetrates things, including our skin. Sunscreen helps by absorbing or reflecting UV radiation, stopping it from entering our skin and causing sunburn which is actually your skin's DNA damaging it and sometimes mutating it, that's why repeat exposure can result in Skin cancer. As for the SPF rating system (Sun Protection Factor), the numbers mean that for, say, SPF 30 sunscreen, the amount of UV radiation you're exposed to is 1/30th as intense as bare skin, assuming you applied enough. Anything higher than SPF 30 is really just diminishing returns, with the difference between SPF 30 and 70 only being 1 or 2% blockage. It's also worth noting that the SPF system only accounts for UVB radiation, so 2 brands that have the same rating may have an overall more or less effective level of protection, so it's always best to get something that has Zinc Oxide in it which provides a broader range of protection. Also! Just because you have SPF 60 that doesn't mean you only need to apply it half as often! Sunscreen gets rubbed off by moisture, towels, clothing and sweating, so if you do any of those things, reapply."], "text_urls": [[]], "score": [4]}}, {"q_id": "862owb", "category": "Repost", "title": "/ Why does hot food smell more than cold food?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dw1urot"], "text": ["Hot food causes some of the water in food to evaporate more easily and this carries food partials with it into the air that we smell. Same happens with cold food but because water is not evaporating as quickly there are less food partials and there is less smell."], "text_urls": [[]], "score": [6]}}, {"q_id": "863me7", "category": "Repost", "title": "Why do men bald, but women don\u2019t?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dw22h99"], "text": ["Women do go bald, but we don't notice it as much. Women most often go bald by losing hair from all over their heads, while in men it usually starts at the crown or at the hairline."], "text_urls": [[]], "score": [3]}}, {"q_id": "8683si", "category": "Repost", "title": "why doesn\u2019t tin foil get hot in the oven?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dw32rju", "dw32oel"], "text": ["It does. It just doesn't stay hot when you remove it. The foil is very thin and Al has a relatively low heat capacity, so the heat contained in the foil is fairly low. (Temperature and heat are not the same thing.) And Al foil is pretty good at radiating what heat it does have, so it cools rapidly.", "It does get hot but a metals such as tin foil are thermal conductors (meaning it transfers heat) so while it can get hot, it transfers its heat and cools very fast. The point of cooking with tin foil in the oven is to stop food that has to cook a decent amount of time from getting dry."], "text_urls": [[], []], "score": [11, 3]}}, {"q_id": "868j4p", "category": "Repost", "title": "Why does excessive heat creates problems during takeoff of airplanes?", "title_urls": {"url": []}, "selftext": "I read somewhere that airplanes have a hard time taking off from places like Phoenix when it's extremely hot. Is it related to air density?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dw36b7i"], "text": ["The higher the temperature, the less density the air has and the less lift the plane gets from it. In other words, the hotter it is, the longer the runway you will need. There are charts for every plane that says lot long the runway needs to be at different temperatures. The charts typically stop at around 120 degs F. If it gets hotter than then the plans are usually grounded until it cools off."], "text_urls": [[]], "score": [12]}}, {"q_id": "86bh63", "category": "Repost", "title": "Flossing, why do it if I brush and use mouthwash, any risks?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dw3qn4i", "dw3vb6n", "dw3sad0"], "text": ["Floss can get to places that your brush can't reach and mouthwash can't clean. Flossing requires you to push the floss into your gums with force. This will \"expose\" unwanted material from the hard-to-reach nooks and crannys for your brush and mouthwash to eliminate with ease.", "As a dentist, a majority of the caries (decay) i see begins from the interproximal(inbetween) section of teeth. The other surfaces of teeth are primarily smooth (except molar and premolar fissures) and easy to clean if you brush regularly. Flossing basically allows you to remove food debris from the interproximal areas where brushing cant reach. As I said a lot of decay starts from inbetween teeth and therefore its even more important that you floss to remove the food and decrease your chance of interproximal caries", "The main goal in dental hygiene is to break up (and ideally remove) tartar, plaque and food deposits. Mouthwash doesn't really help with this, so you may be left with deposits in little nooks and crannies that you can't reach with a brush. Bacteria are free to thrive there as neither saliva nor mouthwash can reach in there to kill them, or neutralize the lactic acid they produce which ultimately leads to tooth decay. So you need to get in there and physically break up the deposits so the bacteria have nowhere to hide. That being said, it depends on your teeth and the gaps between them. If you have very tight gaps between your teeth, it will be difficult to get in there with a brush and flossing may be necessary. Personally I have rather large gaps (or small teeth), so I find (and am told by dentists) that I can usually get by with a good (electric) brush."], "text_urls": [[], [], []], "score": [11, 4, 3]}}, {"q_id": "86bjjg", "category": "Repost", "title": "Why does licking or otherwise wetting your lips cause them to be more chapped/dry?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dw3qoqp"], "text": ["the air around us contains less water than our skin does, so the air flowing over our bodies absorbs a little bit of water from it constantly. To prevent this from getting too bad our skin is covered in a little bit of \"grease\" It's a realy thin layer so we dont notice it, but by licking our lips we remove the layer of grease. (which is already quite thin on our lips) The liquid you apply with your spit only lasts a short while and after that the dry air continues to drain fluid from your lips. So licking your lips isnt realy bad, you just need to do it continuesly all the time for it to be usefull. Lip balm has a similar effect, but for a longer time. So lip balm protects your lips, untill it is gone and then your lips are more vulnerable. This is a realy simplified explenation and I'm quite certain that it's not realy called \"grease\" but you get the point."], "text_urls": [[]], "score": [7]}}, {"q_id": "86ch7f", "category": "Repost", "title": "How do laser guided missiles work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dw3yf1t"], "text": ["The laser illuminates the target with a frequency of light not typically abundant in ambient light. The missile has sensors to detect this frequency and thus can look for the bright spot, adjusting its fins to aim for it."], "text_urls": [[]], "score": [6]}}, {"q_id": "86evhl", "category": "Repost", "title": "What makes something a good conductor of electricity and how does electricity move through objects?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dw4lmnu"], "text": ["A good conductor is a material with freely movable charges. Now electrical charges don't usually occur \"just like that.\" What you have, instead, are charged particles - pieces of matter that have the property of being electrically charged - just like they have the property of having a mass. Which means we can rephrase my answer to: A good conductor is material with freely movable charged particles. The pieces of matter with a positive electrical charge are called protons and make up the cores of atoms (together with so called neutrons that are irrelevant here). The pieces of matter with a negative charge are called electrons and make up the hull of atoms. Any atom or group of atoms that has more electrons than protons is said to be negatively charged. If it has more protons than electrons, it is positively charged. In both cases, it would be called an ion. If protons and electrons are present in equal numbers, it is uncharged. Salted water conducts electricity because salt ions move around inside it. Plastics, with no movable charges, don't. Within pieces of metal, electrons can move freely - this property is what makes something a metal. Within so-called semi-conductors, electrons sometimes can move freely (like in metals) and sometimes can't - hence their name. Now as charged particles move thorugh their medium, they may \"bump\" into other things which will slow them down and eventually halt them. The degree to which that happens is called \"electrical resistence\". A good conductor has a low electrical resistance because there is nothing there for its moving charges to bump into. Typically, an electron in a piece of metal will bump into far fewer things than a Sodium-Ion in a tub of water. Within some materials, so-called supraconductors, moving electrons will bump into nothing and never slow down - as long as they are almost as cold as anything can physically get in this universe. EDIT: Fixed a word, expanded a bit to include electrical resistence."], "text_urls": [[]], "score": [6]}}, {"q_id": "86k3zs", "category": "Repost", "title": "How is radiotion, a carcinogenic, is used in cancer treatment?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dw5mpjj", "dw5n1lr", "dw5mput"], "text": ["Radiation may cause tumours occasionally, but it also directly kills cells. Like most anti-cancer treatments, radiation kills both cancerous and healthy cells. The trick is to make it hit more of the ones you want to affect. That may be achieved by directing the beam in from many separate directions over time, with the tumour at the aiming point. On it's way, the radiation passes through different parts of the body each time but every time it passes through the tumour. So all the other parts receive a smaller dose than the target. Another is to use a radioactive substance that preferentially goes to the right place. Using radioactive iodine is one example as it concentrates in the thyroid gland so is a treatment for hyperthyroidism.", "Cancer is only a possibility when radiation slightly damages the DNA. At high enough doses, radiation completely destroys DNA, causing cell death. Which for cancer is good, because cancer in a nutshell is uncontrolled growth of cells. Killing the cells stops the growth. So doctors use very specialized tools to aim the radiation EXACTLY where the cancer is to minimize cell death in the non-cancer cells.", "The radiation is aimed very precisely in a beam at the tumour, from multiple angles. (Imagine a bike wheel, Where the hub is the tumour And the spokes are the angles the beam comes from) - only the tumour is in every beam, the surrounding tissue gets a much lower dose so theoretically only the tumour dies. Obviously in a person the beam is shaped and angled to account for bones and more sensitive organs to maximise the tumour dose and minimise the rest."], "text_urls": [[], [], []], "score": [12, 6, 5]}}, {"q_id": "86ll4g", "category": "Repost", "title": "What makes our ears feel \"popped\"?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dw5ypcb", "dw61715"], "text": ["Your inner ears are connected to your nose via the [Eustaghian tube]( URL_0 ). This tube regulates the pressure between your inner ear and the world outside your body. When you get a cold that tube can get blocked which in turn can lead to higher pressure in your inner ear which you experience as 'Stuffed cotton balls'.", "Your ear drum transmits vibrations from the air to the ossicles, tiny bones in your inner ear. This is how hearing translates from air vibrations to signals your brain picks up. The Eustachian tube equalizes air pressure on the inside of the eardrum with the outside environment. This isn't always open, and can get further stopped up with mucous when you are sick. You can potentially force it open by yawning, chewing gum, certain motions that stretch your lower jaw in effect. So, why does it get stopped up feeling? If the air pressure is different from one side to the other, your ear drum gets stretched. It can't vibrate freely, instead it is being pushed one way or the other. As a result, it mutes your ability to hear, because it isn't as capable of transmitting vibrations. The popping occurs when you manage to equalize the pressure, allowing your eardrum to move."], "text_urls": [["https://en.wikipedia.org/wiki/Eustachian_tube"], []], "score": [17, 3]}}, {"q_id": "86mv7v", "category": "Repost", "title": "Why is it so easy to get sick at cold weather ?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dw69k44"], "text": ["Various reasons: in winter we\u2019re more likely to be indoors, close together, where infections spread easier In winter we also have less vitamin D. Vitamin D aids the body\u2019s immune system. Also, whilst it may not seem like it, the air is dryer, this allows virus\u2019 to flourish."], "text_urls": [[]], "score": [9]}}, {"q_id": "86nyvj", "category": "Repost", "title": "What does net worth of somebody means?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dw6ifz9", "dw6ibz0"], "text": ["You take all the valuable things the person owns, like a home, investments, bank accounts, maybe a car, etc. Then subtract all the debt the person owes away. What's left is net worth. So if someone owns a $200,000 home, and has $15,000 in an investment account, and $1,000 in the bank and a $10,000 car, but owes $140,000 on the house, $10,000 on the car, and $2,000 in other debt, their net worth would be $74,000. For celebrities, some of their assets are reported publicly (most real estate records are public and some is private), so there's usually a healthy amount of estimation when their net worth is in stories.", "It's their total assets minus their debts. Unless their assets are incredibly diverse, it's probably an easy estimate. real estate value + bank account + stock portfolio are probably the biggest assets, then minus what is probably owed on the house."], "text_urls": [[], []], "score": [9, 3]}}, {"q_id": "86o0i7", "category": "Repost", "title": "How does carbon dating work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dw6inw3"], "text": ["Basically, we know how much ^(14)C is supposed to be in animals and plants when they're alive, and we know how long it takes for the amount of ^(14)C to be halved, so when we measure the amount of ^(14)C we can calculate how long ago it has been since a thing died (as once a thing die it stops exchanging things with the environment, and will thus not replenish it's stores of ^(14)C)"], "text_urls": [[]], "score": [3]}}, {"q_id": "86unn5", "category": "Repost", "title": "Why is it so easy for us to electronically capture and send the sense of sight (via pictures/video), but sharing the sense of smell/touch/taste is impossible?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dw7zx27", "dw7y78j", "dw81g7q"], "text": ["Mu understanding is: Audio and video are primarily waves, easily reproduced on the far end by speakers or displays. Taste and smell use complex analysis of the actual touching and sampling of the actual substance. Touch is sensing the millions of microscopic pressure points acquired when our fingers or skin comes in contact with something.", "Light is relatively easy to capture and reproduce; the information it conveys when arranged in a particular fashion is mostly static. Smell, touch and taste all require far more complex interactions involving not just light but complicated chemical reactions which depend on huge amounts of factors almost impossible to control for. For example, the smell of your peanut butter sandwich. Smells good, right? To reproduce that precisely, you'd need to account for the type of the peanut butter, how old it was, the bread it was on, the jam you used, the air pressure in the room, the temperature, the humidity, the state of your olfactory senses *at the moment of smelling it*, and so many other things that it's an effective impossibility. Light, on the other hand, is relatively well-behaved and fairly static, because it's not as affected by other factors that change its perception as much.", "To add to the rest of the comments points smell is our sensors picking up the actual chemicals... you can\u2019t have smell without the actual chemicals so to send smell you need to have canisters of all the possible smells and spray them out according to what the other person sent... then there\u2019s the problem of refilling them... not worth the hassle... this is the same problem for taste.... Bur for Touch there are actually trying to replicate them I think \u201csmarter everyday\u201d did one or two videos about gloves that can make you feel stuff without actually touching them... but it\u2019s pretty basic compared to what we can actually feel with our skin like softness and so on"], "text_urls": [[], [], []], "score": [7, 7, 5]}}, {"q_id": "86xi56", "category": "Repost", "title": "Why are the planets in our solar system in the same vertical plane?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dw8kiva"], "text": ["The orbits of the planets are coplanar because during the Solar System's formation, the planets formed out of a disk of dust which surrounded the Sun. Because that disk of dust was a disk, all in a plane, all of the planets formed in a plane as well. Stolen from Ask an Astronomer at URL_0"], "text_urls": [["Cornel.edu"]], "score": [7]}}, {"q_id": "86y9ky", "category": "Repost", "title": "How do birth control pills prevent pregnancy?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dw8r4ze"], "text": ["These pills have synthetic hormones that when taken, trick your body into thinking it's pregnant. When you're pregnant, your body doesn't release eggs because it's already got a baby growing inside. So now that you've taken these pills, your body isn't trying to get pregnant. Of course, they're only 99.5% effective when taken correctly, and 92% effective with typical use."], "text_urls": [[]], "score": [3]}}, {"q_id": "86ybgs", "category": "Repost", "title": "While I was microwaving something, I \"smelled\" that it was still cold; on taste test, it was indeed still cold. How does that work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dw8rts3", "dw8ufxc"], "text": ["Cold food is not as aromatic as warmed food. Heat will volatize the oils, aromatics, and flavor compounds in the food.", "If the food is cold, there will not be enough water vapor. The water vapor can carry smelly particles with it and feel like moisture to your nostrils. In addition, water is important for both smell and taste as a medium of the smell and taste. Imagine putting candy on a very dry tongue or having a dry nostril and smelling flowers."], "text_urls": [[], []], "score": [8, 4]}}, {"q_id": "86yf2v", "category": "Repost", "title": "If the primary colors are red, yellow, and blue, why are TV screens in red, green, and blue (RGB)?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dw8sn03", "dw8snxo", "dw8sovi"], "text": ["Alright, so I'm not an expert, but the best way I know to explain it is to do with the way light works. Color with paint is different in a few ways. All three colors, when combined, make black. On the other hand, with light, all three colors make white. Color as we see it in paint and pigments is a reflection of the colors that don't get absorbed into the object, while light is the color emitted. I hope this helps.", "Because the primary *pigment* colours are red, yellow, and blue (actually, magenta, yellow, and cyan) because those absorb one of the three colours of light we can see (green, blue, and red, respectively) so you can mix them to make the other colours by having the mixed pigment absorb two colours and thus reflect one, such as making green by mixing yellow and cyan (yellow absorbs blue light and cyan absorbs red light, leaving green light to be reflected). TV screens *emit* light, so they can just use the light directly. Our eyes detect green, red, and blue light.", "Because the primary colors are used in painting where the color is created by subtracting light out of the the white light, that works pretty well with RYB. On a tv the color is created by adding three colors in different intensities mixing into new colors, that works pretty well with RGB. That is the difference between subtractive colors and additive colors"], "text_urls": [[], [], []], "score": [5, 5, 3]}}, {"q_id": "86zk6u", "category": "Repost", "title": "why are some sounds in the English language spelt the same but pronounced differently?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dw92wex"], "text": ["One of the reasons is that all languages naturally change over time, especially in regards to pronunciation. Our spelling is kinda fixed by convention - we tend to resist changing the spelling to reflect changes in pronunciation."], "text_urls": [[]], "score": [3]}}, {"q_id": "870aeo", "category": "Repost", "title": "Why do oranges have / grow a smaller orange inside of them.", "title_urls": {"url": []}, "selftext": "I just ate an orange and was wondering why. Is it normal?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dw99p4j"], "text": ["That's a navel orange, and no, it's not normal -- they're mutants, and the particular mutation only dates back to the early 1800s. They're popular because they have no seeds, but because of this, every navel orange tree has to be grown from cuttings and they're all genetically identical: URL_0"], "text_urls": [["http://nowiknow.com/navel-oranges-the-mutant-clones-in-your-kitchen/"]], "score": [9]}}, {"q_id": "870d5g", "category": "Repost", "title": "How did the Nintendo game Duck Hunt know where you were aiming the gun?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dw97p3v", "dw99zgc", "dw9aq8h", "dw9hf32", "dw9ieg5"], "text": ["The original duck hunt was designed for CRT televisions and would not work on an LCD. A CRT (cathode ray tube) works by spraying a stream of electrons at a screen which has pixels that glow when the electrons hit it. The spray progressively sweeps from left to right; top to bottom. It would do this about 100 times per second. The duck hunt gun was a small focusing lens and a white light sensor (like a solar panel but optimized for sensing). When you pull the trigger, the whole screen displays black for a few microseconds and then the area around the ducks lit up as white squares one at a time. Each duck gets its on flash one at a time. When the gun saw a white square through its photosensor, the game would stop progressing through squares and report it hit that duck based on the timing. **Edit: thank you for the gold kind stranger!** **I'll post this as a bonus.** Duck hunt already made me go viral once before. It turned me into a meme in college. After getting second in a dorm duck hunt drinking tournament, we stole the controller and posted this to college humor: URL_0", "When you press the trigger, the screen turns black and all the targets turn into white squares, for just a fraction of a second. The gun detects whether or not it's pointed at something bright (the white squares), hence the term \"light gun\".", "But how does it know which duck was hit?", "Dammit, finally one I know the answer to and I'm way too late. Anyways, answer is that when you pull the trigger, the whole screen turns black except for the square with the duck. Gun has a sensor and can tell if it is pointed at white or black.", "> I can see how this would work on the wii but the NES didn\u2019t have a sensor bar or anything. It actually works on the same principle. What do you think the sensor bar does? The Wiimote, just like the NES light gun, is a *camera*. You can learn more about it in [this old TED talk]( URL_0 ). The Wiimote sees light from the sensor bar, sends the location of that light to the Wii, and the Wii calculates where the Wiimote is pointing. But wait, you say. The sensor bar is a sensor; it doesn't emit light! NOPE. The \"sensor bar\" is nothing but a pair of light bulbs at either end, but you can't see the light because it's infrared. However, it's *near* infrared, so if you point your cell phone camera at the sensor bar, you'll be able to see the lights! Same thing with your TV remote, actually. Your Wiimote camera sees the two lights on the sensor bar and relays that information to the Wii. But really, any infrared source will work. You can use a pair of incandescent bulbs or even candles. The NES light gun works on the same principle, though with with so much less processing power, Duck Hunt uses tricks to know whether you hit a duck rather than calculating the position of the gun. The light gun is still a camera, but instead of seeing a sensor bar, the light gun sees what's on the actual screen, though only with a narrow angle. The game puts signals on the actual screen that the camera reads; in this case, it flashes the screen and the ducks' hit boxes in different ways and the light gun sends to the console what it saw in the small region it was looking at. In both cases, the whole thing is a misdirection. The products are shaped and marketed to make you think that the console is seeing these toy items you're holding -- we all know that guns shoot things *out*, for example, so obviously the gun is shooting a signal that is being received somehow, just like in laser tag, right? -- but in reality, the opposite is happening; the TV is shooting the signals to the gun, which is the receiver, not the sender. Same with the Wii; the Wii tells you that it has a \"sensor bar\", which is obviously a sensor, sensing things, but in reality, the sensor is in the Wiimote and the sensor bar is nothing but a pair of infrared LEDs. On the other hand, the Kinect is a real camera that can really see you."], "text_urls": [["https://i.imgur.com/iexPEqW_d.jpg?maxwidth=640&amp;shape=thumb&amp;fidelity=medium"], [], [], [], ["https://www.ted.com/talks/johnny_lee_demos_wii_remote_hacks"]], "score": [14673, 689, 91, 9, 4]}}, {"q_id": "870lum", "category": "Repost", "title": "why do cables/wires tangle when you leave them?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dw99hr6"], "text": ["Entropy. There are basically infinite configurations for a cable to be \"tangled\", and only a few where it is neatly coiled. As the cable moves around randomly in your pocket, the odds are hugely in favor of it going from an organized state to a disorganized one. It's theoretically possible for you to put a cable in your pocket tangled, and find it neatly coiled later, but it's so unlikely that it will practically never happen."], "text_urls": [[]], "score": [3]}}, {"q_id": "872gq5", "category": "Repost", "title": "How does \u201clooking up at the sun\u201d help make us sneeze?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dw9phtz"], "text": ["Somebody alerted me the other day it's called a photic sneeze reflex. Indeed only a percentage of the population is affected by it. URL_0"], "text_urls": [["https://en.m.wikipedia.org/wiki/Photic_sneeze_reflex"]], "score": [5]}}, {"q_id": "8743g6", "category": "Repost", "title": "Why are gas stations allowed to chard fractions of a cent?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dwa0u6v"], "text": ["Because *anyone* is allowed to charge fractions of a cent, as long as they round the transaction at the end to something the payer can pay (the nearest cent)."], "text_urls": [[]], "score": [4]}}, {"q_id": "874ee7", "category": "Repost", "title": "How debt between countries works", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dwa3gqj"], "text": ["Debt isn't between countries. Debt is held by investors who buy the debt in the form of bonds. So U.S. debt is held by whomever decides to invest in U.S Treasury bonds -- about 75% are held by Americans and American institutions. Other counties similarly sell bonds to fund their operations, selling their debt to investors domestic and foreign."], "text_urls": [[]], "score": [3]}}, {"q_id": "876dgd", "category": "Repost", "title": "Why do humans get that orgasmic sensation when they clean their ears with a q-tip?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dwalugq"], "text": ["You have a ton of nerve endings in there. It\u2019s similar to scratching an itch in that regard."], "text_urls": [[]], "score": [3]}}, {"q_id": "877qzw", "category": "Repost", "title": "What do producers and production companies actually do?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dwatrkr"], "text": ["Production largely refers to the organization process of bringing everything together needed for making a movie. From finding locations to casting, hiring costume designers, actors, stylists, make up artists, props, securing rights to songs used in the sound track, hiring camera crew, lighting crew etc etc. Quite often the titles Producer & Executive Producer can also refer to the organizing of funds to cover the cost of all of the above. Producing Anime would likely refer to the hiring of artists, writers, directors, editors etc etc."], "text_urls": [[]], "score": [3]}}, {"q_id": "87fakx", "category": "Repost", "title": "How stainless steel soap bars work to remove garlic/fish smells", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dwcqtgj"], "text": ["Also: 1. [ELI5: How do stainless steel soap bars work? ]( URL_1 ) ^(_2 comments_) 1. [ELI5: using steel to get rid of smell ]( URL_2 ) ^(_11 comments_) 1. [ELI5:How does rubbing your hands on a piece of stainless steel under running water get rid of smells like garlic and fish? ]( URL_3 ) ^(_3 comments_) 1. [ELI5 how do metallic soaps work? ]( URL_0 ) ^(_6 comments_)"], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/4kgt60/eli5_how_do_metallic_soaps_work/", "https://www.reddit.com/r/explainlikeimfive/comments/16twcg/eli5_how_do_stainless_steel_soap_bars_work/", "https://www.reddit.com/r/explainlikeimfive/comments/6w4uks/eli5_using_steel_to_get_rid_of_smell/", "https://www.reddit.com/r/explainlikeimfive/comments/1cxed6/eli5how_does_rubbing_your_hands_on_a_piece_of/"]], "score": [3]}}, {"q_id": "87r79u", "category": "Repost", "title": "Why do bigger explosives form a \"mushroom cloud\" when they go off?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dwewnmk", "dwf7zpd"], "text": ["They make hot air. Hot air rises (the stem). This rising hot air carries debris (the cloud). Eventually the rising air reaches equilibrium with its surroundings and spreads out (the cap).", "The initial explosion creates a high pressure blast wave that leaves a very low pressure region at the point of the explosion as it travels outward. After the wave passes, the low pressure void is filled by an inrush of higher pressure surrounding air. Since the air is coming in from all sides, there is only one way for it to go in the center where it meets - up. So the rising cloud you see is the result of dust, smoke, and debris being sucked back into the low pressure zone and then being pushed upward."], "text_urls": [[], []], "score": [80, 14]}}, {"q_id": "87vbnk", "category": "Repost", "title": "Why do scientists try to find oxygen to find life on other planets? Aren\u00b4t other forms of life-based on other chemical elements possible?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dwft77j"], "text": ["Usually we're looking for water, not oxygen. And this is because all life on Earth as we know it requires water, and since this is our only example of actual life, we are looking for similar conditions elsewhere. Is it *possible*? Sure. But we don't know if it actually happens/exists so we're looking for signs based on what we DO know."], "text_urls": [[]], "score": [6]}}, {"q_id": "885j1w", "category": "Repost", "title": ". Why don\u2019t buildings suffer from water damage and/or mold when it rains while they are being built?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dwi63co"], "text": ["They usually crank the heat up to around 100\u00b0f and use large dehumidifiers once the building is weather tight to \"cook\" out any moisture. Sometimes even after this mold can still form."], "text_urls": [[]], "score": [11]}}, {"q_id": "886az4", "category": "Repost", "title": "What's the difference between brown eggs and white eggs?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dwi7ks3"], "text": ["There is no nutritional difference between white and brown eggs. They simply [come from different types of chickens.]( URL_0 ) There\u2019s actually blue and speckled chicken eggs as well."], "text_urls": [["https://m.huffpost.com/us/entry/1342583"]], "score": [4]}}, {"q_id": "88img9", "category": "Repost", "title": "I asked my cylinder today what the weather is. It said \"Today will be a high of 54 and a low of 43. It is currently 39.\" Why is 43 desginated as the low when its clearly not?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dwkuhds"], "text": ["It's giving you tonight's expected low, not this morning's. It does no good to know how cold it was early this morning. I want to know how cold it will get later."], "text_urls": [[]], "score": [21]}}, {"q_id": "88j5t8", "category": "Repost", "title": "Why are so few naturally occurring foods truely blue?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dwkz02d", "dwkz0cj", "dwl4q8u", "dwl5bl8"], "text": ["Basically, it's because most animals don't see blue. Fruit produced to be eaten is colored to contrast with the green leaves. Leaves are green because chlorophyll is effective at using light for photosynthesis and chrolophyll is green. So the ideal fruit color would contrast sharply from the green in another color that animals can see. Like yellow or red or orange. But blue is not a common photo detector. This is why flowers often have bright patterns that only need and other pollinators can see. They're colored in the ultraviolet spectrum that humans can't see and look different to bees. Another way to look at it is the other way around. Looking at the fossil record it's hard to say if animals evolved to see the colors fruits were or vice versa. Chicken or the egg. Suffice it to say animals and plants co-evolved to see and be seen.", "(True) Blue is one of the rarest colours in nature. Most colours in nature are caused by pigments like in our skin however, blue pigment is extremely rare. The blues that we see on most insects and in our eyes are caused by the shape of the surface only bouncing back the blue wavelengths of light. Also there is not normally any selective advantage (depending on the environment and selection pressures) for a plant to be blue in the first place. The chlorophyll in most plants absorb the blue wavelengths of light (and reflect the green) therefore if the plant reflected it, it would be loosing a great amount potential energy to create food. URL_0", "also why is there no natural blue or green hair colour?", "Then why do flies and insects have an affinity for blue wavelengths? If it wasn't a viable way to food, why wasn't it removed by evolution??"], "text_urls": [[], ["https://m.youtube.com/watch?v=3g246c6Bv58"], [], []], "score": [1099, 62, 12, 3]}}, {"q_id": "895b14", "category": "Repost", "title": "Why do we have fingerprints?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dwp0o7u", "dwpbodb", "dwp5wd5"], "text": ["They help with grip: the ridged surface is a little bit better at holding on to objects than a flat surface would be. They're on your toes as well because of your primate ancestry: your great (x 10000) grandpa picked stuff up with his toes more often and it came in handy (footy?). It never evolved out because there was no reason to.", "I don't know the true answer to this question but read an interesting article a few years ago describing how adding fingerprints to a robotic finger actually increased the touch sensitivity of the sensors underneath. I don't have any quantitative data to back it up, nor any clue where to find the article again as it was a somewhat obscure website from what I remember. That being said, I find it a kind of fascinating and and intriguing theory to that of the more common increases in in grip friction or it being an evolutionary accident.", "Fingerprints don't help create as much friction as previously thought. The bumpy ridges on the tips of our fingers are an evolutionary mystery. They are on your feet and many parts of the body, just less noticeable. Many ancestor have textured swirls. Perhaps to transport immunizing germs to our family. They could improve sensory density. Most likely they are a vestigial abrasive to better preen insect."], "text_urls": [[], [], []], "score": [44, 4, 3]}}, {"q_id": "89rmq6", "category": "Repost", "title": "Why do computer applications sometimes freeze up to the point where you can't even click within or exit the application?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dwt0crt", "dwt0tbu", "dwt1kba"], "text": ["Usually this happens when the application runs into an error (stack overflow, access a file that doesn't exist). Imagine the computer is a person who just dropped their stuff on the ground, and the computer freezing is them picking it up. They're so concentrated on fixing the problem, they put all their resources to fix it, including the processing power needed to move your cursor. Hope this helps", "Many code operations in an application will cause the application to stop listening to click or keypress events. Usually these operations complete quick enough that you don't notice it. In some cases, they take some time, but the developer puts up a visual indicator that the app is busy (such as a progress bar). A more advanced technique (that's not always possible, due to design constraints) is to execute code asynchronously from the interface, so when a user causes some code to run, they can still do other things in the application. With that information, the answer to your question is that an app \"freezes\" and stops accepting user input when it's running some code that causes the app to stop listening for user input and a bug in that code causes it to never complete (or crash, but usually crashes will crash and close the whole app). **Edit:** typo", "Hey! Finally one I *can* answer: Your computer is finite and has a finite amount of resources. You (as a person) can only multitask and do a few things without slowing down and losing quality of what your trying to do. Don\u2019t believe me? Try writing two different sentences on paper with each hand. Now, instead of trying to do both at the same time, write one word or one sentence after the other. You get it done a lot faster and better. This is what computers do, though they\u2019re a lot faster, they actually do one thing at a time. It just happens to go so fast it looks like they\u2019re doing it at the same time. Now, continuing with our human example, when you\u2019re writing your sentences, what if you don\u2019t know how to spell a word, or your pencil breaks? You have to stop and figure out what went wrong, and try to fix it. If you can\u2019t figure out how to spell it, or don\u2019t own another pencil, you\u2019re stuck. What makes us different than computers is that when something goes wrong for us, we always have alternate solutions. For example, we can grab a pen or look up a word in a dictionary. We can see alternatives. When a computer has these kinds of errors it depends on how well the programmer made the program. If it\u2019s a good program, it has pre-built alternatives that don\u2019t stop it from accomplishing its task. If it\u2019s a poorly written program, or something goes extremely wrong, the program, or the computer entirely will stop because it doesn\u2019t know what to do. This is what causes computers or programs to freeze, or crash."], "text_urls": [[], [], []], "score": [41, 24, 10]}}, {"q_id": "89smur", "category": "Repost", "title": "Why can an ant fall from a distance and not be injured while we can't?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dwt7bjc"], "text": ["Ahoy, matey! Yer not alone in askin', and kind strangers have explained: 1. [ELI5: How can insects fall from proportionally insane heights and suffer no damage? ]( URL_3 ) ^(_ > 100 comments_) 1. [ELI5: Why can bugs fall from such great distances but humans can't? ]( URL_1 ) ^(_7 comments_) 1. [ELI5:Why can ants fall from many times their height and still be ok? ]( URL_4 ) ^(_10 comments_) 1. [ELI5: Why don't bugs take fall damage? ]( URL_0 ) ^(_61 comments_) 1. [How the hell do bugs not take fall damage??? ]( URL_2 ) ^(_10 comments_) 1. [How come an ant can fall 20 times its body length and end up unharmed, but people can't? ]( URL_5 ) ^(_7 comments_) 1. [How do ants survive enormous falls that would kill us? ]( URL_6 ) ^(_ > 100 comments_)"], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/3oj2eu/eli5_why_dont_bugs_take_fall_damage/", "https://www.reddit.com/r/explainlikeimfive/comments/3n4j0q/eli5_why_can_bugs_fall_from_such_great_distances/", "https://www.reddit.com/r/NoStupidQuestions/comments/6nawt0/how_the_hell_do_bugs_not_take_fall_damage/", "https://www.reddit.com/r/explainlikeimfive/comments/1f9sjz/eli5_how_can_insects_fall_from_proportionally/", "https://www.reddit.com/r/explainlikeimfive/comments/37nt8t/eli5why_can_ants_fall_from_many_times_their/", "https://www.reddit.com/r/explainlikeimfive/comments/195pw7/how_come_an_ant_can_fall_20_times_its_body_length/", "https://www.reddit.com/r/explainlikeimfive/comments/jlooi/how_do_ants_survive_enormous_falls_that_would/"]], "score": [9]}}, {"q_id": "8aavb0", "category": "Repost", "title": "How do tv and radio stations figure out how many viewers/ listeners they have? When recording show on a DVR, does that count?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dwxa3xd", "dwx77tc", "dwxbl28"], "text": ["It's based on surveys conducted on behalf of or by the station. People will get a packet that they have to keep track of what they watch/listen to, then mail it back in. There is a section for what you watch live vs DVR, but ultimately it's up to how the respondents record the information. Some areas will use a random sampling via phone call as well. Radio stations will do this a lot to make sure they are playing the kind of music that pulls in the demographic they want to sell advertisements for.", "It's a statistical extrapolation based on small samples. Often people will keep diaries of their viewing and listening. They could include recording or watching recordings off-air, it depends on how detailed a survey they want the results to include. The British BARB organization methods - URL_0", "In the past, they installed boxes (Nielsen boxes) into some peoples' homes that tracked what you were watching. Nowadays, your television provider can tell exactly what shows you watch, what you DVR, and what you watch on-demand. Theoretically, they could use this information to provide better programming (Netflix claims to use their data to help them choose where to invest in new shows)."], "text_urls": [[], ["http://www.barb.co.uk/about-us/how-we-do-what-we-do/"], []], "score": [8, 5, 3]}}, {"q_id": "8adcy8", "category": "Repost", "title": "Why are chips on credit/debit cards supposedly more secure than swiping? Also, how does the bank, business, and card reader share information?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dwxqy76", "dwxqz1r", "dwxrban"], "text": ["Ooh, long story short, chip cards only protect you in the event of someone trying to make a fake card with your number and use it at a store. With magstripe cards, the data from the stripe could very easily be copied to another card (even a hotel card) and used at a store with no problem. The chip in new cards is a mini computer that generates a unique code for every transaction, that the server validates. That unique code can only be generated by that card, and the chips cannot be duplicated like a magstripe. Chip cards, however, don't protect you at all for online transactions, as the chip is bypassed completely... New tech in the industry like Apple pay is starting to shift the paradigm for these types of payments.", "The short answer is that EMV chips are a lot harder to clone (i.e manufacture duplicate cards) than magnetuc strips. They also cant be read by skimmers (devices covering insert slots on ATMs or other devices that read thw magnetic strip). However these are not insurmountable obstacles for thieves. US really needs to catch up withe Europe and institute Chip and Pin so the purchaser has to both have something and know something to access your account.", "All the information on a magstripe can be easily read and therefore easily duplicated. A chip contains a secret code that can't be read by anyone so it can't be easily duplicated. Chips work by using their code to transform some challenge message sent to them. This way they can prove they have the code without ever revealing what it is."], "text_urls": [[], [], []], "score": [13, 4, 3]}}, {"q_id": "8akjxk", "category": "Repost", "title": "How does wind work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dwzc9o7"], "text": ["Air moves from areas of high air pressure to low air pressure (water and other liquids also do this). That movement of air is seen and felt as wind."], "text_urls": [[]], "score": [3]}}, {"q_id": "8alsbi", "category": "Repost", "title": "Why does hearing your own voice through a recording sound so much different than how you hear/perceive your voice when speaking in general?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dwzm0o5", "dwztjza", "dwzposj", "dwzy1fg", "dwzm2xt", "dx035b0", "dx00ayt", "dx01j3j", "dwzpkf0", "dx01c45", "dx07kgm", "dx014my", "dx01pkv", "dx0a6o3", "dx0491c", "dx038mw", "dx006t9", "dx00qtz", "dx020is", "dx01m9h", "dx020s5", "dx03b7a", "dwzzy3l", "dx0jd2j"], "text": ["When you speak, you hear your own voice as it sounds vibrating through your head (for lack of a better way to say that). When you hear your voice through a recorder, you're hearing your voice without that vibration. Edit: Had I know so many people would see this, I would have tried explaining a lot better than I did here but thanks either way!", "I've always wondered how great impressionists do it. If you can't hear yourself correctly how can you impersonate someone else correctly? I know my Michael Cane impression sounds perfect in my head, but when I hear it recorded it sounds way more nasally.", "Related question: Can you hear someone else\u2019s voice the way *they* hear it? If so, how?", "Slightly different question, why does hearing your own voice through a recording always sound bad? Why isn\u2019t anyone ever pleasantly surprised at how their recorded voice sounds instead of disgusted and horrified??? Edit: it appears some people do in fact like the way their recorded voice sounds! TIL!", "When you speak, you are hearing your voice from multiple pathways. One is out your mouth, outside your body, and into your ear, and this is how others will hear you. But competing with that is the path from inside your head, from vocal cords to cochlea. The structure of your head enhances the lower-frequency vibrations, and so what you hear is a mix of the the two sounds (internal and external). On a recording, you only hear the external. Source: URL_0", "One of my favorite parts of speech training! A long time ago, when your grandpa was a little boy and dinosaurs still roamed the earth there was a toy that children made out of two tin cans and a length of string--you've probably seen this in a cartoon. The way this works is that your voice makes the first can vibrate, the vibration is carried along the string which makes the second can vibrate, THAT can makes the air vibrate and you hear the speaker coming out of the can... That's basically what's happening when you listen to a recording of anyone, including yourself. But \"what if\" instead of two tin cans you used 1 tin can and a pie tin. A pie tin isn't very good at vibrating the air like the tin can was so I'm not sure if you'd be able to hear it very well... UNLESS you held the pie pan tightly against your ear... then you'd hear it really well! Even better than you did with the tin can. That's basically what's happening when you listen to yourself speak without a recording. In the first example you heard the voice as it vibrates through air, in the second example you heard the voice as it vibrates \"through pie pan\". In the real world that \"pie pan\" is your skull.", "Is there a way to simulate how your friends voices sound through them?", "That\u2019s gotta be weird for people that sing for a living. You hear yourself on the radio and may HATE your voice.", "It's been posted many times before, but we all have three voices: 1) the one we hear in our head 2) the one we hear when we talk aloud 3) the one everyone else hears", "One more thing I want to add from what everyone else is saying. The microphone also affects how different your voice sounds. You voice sounds a lot worse wen recorded through an iPhone, as opposed to a high quality microphone.", "So I am a Voice and Speech teacher ( from a theatrical background rather than a medical one - think Geoffrey Rush's character in The King's Speech). This is what I tell students - imagine you were confronted with your own image (a photo or a mirror) when you are either a teen or an adult for the very first time. At first you would probably reject the reflection - you have no relationship to it, how can it be your own face... the very concept of having a relationship to this reflected thing is foreign. It's only with continued exposure to that image or recording that we can begin to have a relationship with it. Secondly the mechanics of hearing - when you speak normally you are listening to your own voice from two sources at once - through your ears (your brain automatically adjusts your perception of your voice to be lower in volume than it is so you don't overwhelm your hearing - which is why we can scream and not hurt our ears much) AND through the internal vibrations of the larynx and resonates through the bones of the skull. That is when you take much notice of your voice at all. Thirdly! A recording cannot pick up the warmth of the human voice - with all the strides in digital recording it is no substitute for a live human voice that is not amplified or distorted through a Mic or recording device (a recording or amplified voice will always sounds slightly \"tinny\") All 3 reasons are why we reject our recorded voices so violently when hearing them the first time. But anyone who is in the entertainment industry will tell you - that goes away and you can start listening to your performances and start to know how to adjust them so they sound better outside your head once you have a working relationship to your voice. (That sounds like an Ad! Heh heh)", "Lots of good answers but they don\u2019t explain why when I hear someone else\u2019s recorded voice, it sounds different than how I hear it IRL.", "I\u2019m on the radio weekly. It used to freak me out but now that I know how I sound I play the role of the person I hear. It\u2019s like I know it\u2019s me, but I\u2019m playing \u201cme\u201d as others hear me. Truth be told it\u2019s pretty liberating.", "The important thing to remember is that despite our disgust at hearing our voices, whenever anyone new hears us talk they're not vomiting at the sound of it.", "So do the majority of people who hate listening to themselves when they hear a recording of their voice, hate it because they are so used to how they would naturally be hearing themselves speak? I mean if I\u2019m so used to hearing myself speak on a daily basis, then I am confronted with a recording of myself where my voice is completely different to my perceived norm, I wouldn\u2019t like it either haha", "Am I weird for liking my recorded voice?", "When speaking in general, there are two ways by which sound reaches your ears. Firstly, the air in your larynx (voice box) vibrates, reaches out and hits your tympanic membrane(ear drum) and from there converted to electrical signals and perceived as sound. This is Air conduction Secondly, sound from the voice box travels through the bones in your body (your skull bones, facial bones) and directly reaches an organ in your inner ear called the cochlea. Cochlea is the organ that is responsible for converting sound(or any vibrations) to electricity. When you listen to yourself speak, both these ways are there. When you hear it through the recorder, you only hear the first pathway i.e air conduction only. And it sounds different because the other pathway is 'missing' from the recorder. With some people their voices may sound so different from a recorded sample that they may not recognise it as their voice.", "Semi related question. When you plug your ears Your singing sounds worse. Are you actually worse, or are you just hearing how you actually sound?", "What's crazy to imagine is only in the last 150 years or so did humans even realize they sound different than what they hear. I can't imagine we would have known before sound recording was invented by Edison.", "Related question: Podcaster I listen to says he gets expensive microphone equipment so that he sounds the same way on recordings as he does in his head. Doesn\u2019t this mean the whole skull vibrations thing is more complicated than that?", "As others pointed out, what you know as \"your voice\" is how your brain percieves your talking, not how it actually hears it. In a sense, you get kind of a *preview* of your speech because the sound echoes directly into your own ears as your brain predicted. If you want to actually hear yourself, take two folding papers or magazines, just about any hard flat surface larger than your head will do. Place a pair, one for each ear, against your face covering your ears at a 45\u00b0 angle. Speak casually as you would, that's how we hear ya.", "In a nutshell, bone conduction. Sympathetic vibrations in your skull cause you to hear your voice differently in your head.", "Your voice is speaking inside your body (like talking in a room by yourself) and as it goes out the open doorway of the room, it is no longer amplified by the walls of the room. That's why your voice sounds different.", "When we talk we hear the air that comes out along with the vibration of our bones. It\u2019s called Bone Conduction, other people or devices don\u2019t pick this up so we always sound different to how others hear us, typically we sound deeper or lower pitch to ourselves because of the bass-y effect of our bones vibrating. I think if you use a really good microphone, it can pick this stuff up but your typical one on a mobile or headset won\u2019t."], "text_urls": [[], [], [], [], ["https://www.scientificamerican.com/article/why-does-my-voice-sound-different/"], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], []], "score": [6501, 2395, 843, 672, 343, 87, 82, 77, 63, 51, 31, 23, 22, 13, 13, 11, 11, 7, 7, 5, 4, 3, 3, 3]}}, {"q_id": "8b6q3p", "category": "Repost", "title": "How do we know universe is approximately 14 billion years old?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dx4czb3", "dx4cy03"], "text": ["The first method is to use the current expansion rate and work backwards to find out how long it took for the universe to expand to its current size. The second method involves looking at stars. Imagine there is a stopwatch somewhere in this universe that says it has been running for 13 billion years. The existence of this stopwatch means that that universe is at least 13 billion years old. The oldest stars act as this stopwatch, by finding out the age of the oldest stars we can find, we can find out the youngest age the universe can be. Since both methods depend on different things, if both methods give roughly the same answer, we know that it's likely to be correct.", "IIRC, it\u2019s because the universe is expanding at a set rate. If you know how long it takes for two bodies to move away from each other, and you know the rate at which they are moving apart, you can calculate back to the point where those two bodies were in the same spot."], "text_urls": [[], []], "score": [26, 9]}}, {"q_id": "8bh1tq", "category": "Repost", "title": "How does buying and selling stocks work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dx6mvz3"], "text": ["You should try [this post]( URL_0 ) for some good explanations."], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/1oot71/eli5_how_does_the_stock_market_work_who_are_the/"]], "score": [3]}}, {"q_id": "8brhpj", "category": "Repost", "title": "Why is the sound of rain so soothing?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dx90pkq", "dx95mrb"], "text": ["It's the original white noise. To much for your brain to process so it sort of shuts down and becomes part of the audio enviroment.", "My unqualified guess would be that it is not too unsimilar to the soothing effect sitting around a campfire has. Prehistoric people would feel protected from predators around fire knowing that most predators feared fire. Similarly, if they are sheltered from a heavy or steady rain, they assumed that their predators were seeking shelter as well. Therefore they enjoyed a brief respite from needing to be constantly vigilant and alert."], "text_urls": [[], []], "score": [3, 3]}}, {"q_id": "8ccip4", "category": "Repost", "title": "How do \u201csafety tabs\u201d prevent erasing content on a cassette tape?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dxduxsb"], "text": ["Cassette recorders have a microswitch to detect the tab. If the tab is detected, it allows recording. Breaking the tab off is the same as hitting the write protect switch on an SD card. It tells the recorder to not record. Nothing a little scotch tape can't fix!"], "text_urls": [[]], "score": [7]}}, {"q_id": "8ceg96", "category": "Repost", "title": "When their is no reception and get \"SOS Only\", How come emergency services can be contacted but no one else?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dxeaktv", "dxeabcr", "dxeajtd", "dxegr7a", "dxead6z"], "text": ["Emergency service has special rules. It has reserved capacity on the towers, so you can use it even when you couldn't make a call otherwise. You can also use it even if you don't have balance, an active account, or a SIM card at all, and the call will be accepted by any tower capable of communicating with your phone. Provider restrictions don't apply for emergencies. If you have a normal, working phone and an active account, then the most likely reason is that you're outside your operator's area of coverage.", "That generally means either your phone can see a network but not your own carriers network or you have an inactive SIM (disconnected, out of credit etc)", "In SOS mode any nearby towers (regardless of network) will treat your call as a top priority, even if it means dropping other signals or 'boosting' your own. It's similar to cell boosters (highly illegal) they draw more 'attention' to your connection, where as SOS mode informs the tower you require more attention.", "When you make a normal call it is done at normal power levels with average priority to a cell tower associated with your phone company When you dial 911 or equivalent the rules change. Your phone will do everything possible to connect to the nearest tower of any network, that tower *must* take your call and *must* shed load if necessary to ensure your call does not get dropped. Emergency calls are higher priority than any other traffic on a cell tower and the tower *must* keep that call connected even from an inactive phone or a phone from another provider", "\"No service\" means that you don't have a strong enough connection to any towers belong to your carrier to operate under normal conditions. In an emergency, you'll connect to other networks, use more transmit power, flaky connections and stuff like that."], "text_urls": [[], [], [], [], []], "score": [12, 6, 4, 4, 3]}}, {"q_id": "8cjbep", "category": "Repost", "title": "Where does fat mass go and muscle mass come from?", "title_urls": {"url": []}, "selftext": "I\u2019ve lost 75 pounds over the past year and I\u2019m wondering where all the fat mass has gone and all the muscle mass came from", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dxfeui4", "dxfe4v0", "dxfdut8"], "text": ["It mostly goes into the CO2 that you exhale into the air. Plants then get most of their mass from that same CO2, not the ground that they\u2019re in.", "Fat cells are stored energy so when your body runs low on its energy systems it will use the fat as a resource to fuel the body. This is why you should consume less calories to lose weight so your body can expend fat for energy. Muscles, unlike fat, does not come or go. It gets bigger or smaller through swelling of tissue after repairing microtears from lifting weights or putting stress on a muscle.", "Food, water, and breath go in, pee, sweat, poop and breath go out. What used to be fat mostly left as breath and pee, but you can't track it in detail."], "text_urls": [[], [], []], "score": [12, 6, 3]}}, {"q_id": "8cmkx1", "category": "Repost", "title": "How does a petrol pump know when to stop filling?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dxg2px5", "dxg2tz9", "dxg2mz8", "dxg2o4a"], "text": ["There is a smaller tube inside the pipe that goes in your tank. This is the \"sensing pipe\". The small tube connects to a valve that shuts off the flow. When the tank is full, fuel reaches the end of the nozzle, this pressurizes the small tube which activates a valve which shuts off the flow of fuel. URL_0", "At the tip of the nozzle is a small hole. As fuel is flowing the pump sucks air up this hole (leading to a tube that connects to the manual linkage of the handle) due to the Venturi effect of the flowing gasoline. When the hole in the tip is covered by fuel, the degree of suction changes markedly and it trips a linkage in the handle to cut off the fuel. This is why when you often first start pumping fuel the nozzle may cut off a few times but by repositioning the nozzle it will suddenly work-what happened is that in this situation you placed the nozzle in such a position that the suction hole was covered and the handle sensed it as a full tank.", "It has a little sensor tube at the end of the nozzle, and somehow it can sense backpressure, so when that gets to a certain point it cuts it off. If you look closely \\(usually on the underside\\) you can see the sensor tube.", "Air is being pulled through the pump, so when the tank is full of gas it blocks the suction and a sensor detects the change, which stops the gas from flowing"], "text_urls": [["https://en.wikipedia.org/wiki/Fuel_dispenser#Automatic_cut-off_in_fuel_dispenser"], [], [], []], "score": [31, 12, 4, 3]}}, {"q_id": "8csxxo", "category": "Repost", "title": "Why are train tracks surrounded by rocks?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dxhk61i"], "text": ["It's called [ballast]( URL_0 ). It's to provide good drainage and distribute the weight of a train out from the railroad ties into the ground. And it means that you don't have be perfect about getting your subgrade completely flat and level."], "text_urls": [["https://en.wikipedia.org/wiki/Track_ballast"]], "score": [10]}}, {"q_id": "8drjxg", "category": "Repost", "title": "When you hold a sea shell up to your ear, what is the \"ocean\" noise that you can hear?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dxpgb51"], "text": ["The shell itself acts like a resonance chamber, allowing sound waves to bounce around, amplifying some frequencies. The ocean sound is simply ambient sounds such as the wind or even the sound of blood flowing around your ear being resonated by the shell."], "text_urls": [[]], "score": [7]}}, {"q_id": "8ea37s", "category": "Repost", "title": "Why do space rockets need to travel at such a high speed in order to break free from Earth's gravity since gravity decreases the further you get from the center? Also, in the first seconds after launching they move at a relatively slow speed and are still able to achieve lift off.", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dxtn0i2", "dxtlhly", "dxtnht9", "dxtybvf"], "text": ["Source: I've played Kerbal Space Program. Imagine that you threw a ball up. It would constantly decelerate until it some point, it would stop moving, and then started to fall back down. Unless you threw the ball at high enough speed that gravity becomes weaker faster than the ball slows down. The tipping point is called escape velocity. And as it turns out, the most efficient way to do this would be by just getting to that escape velocity instantly. The reason for that being, that way you spend less time near Earth where gravity is slowing you down a lot. If you do slower acceleration, you're wasting fuel fighting stronger gravity. This gets complicated by atmosphere though, as it slows things down too, but basically to save fuel, the moment you are out of the atmosphere, you want to have that target velocity. At lower parts of atmosphere you may want to avoid too high speeds, but you also want to clear from atmosphere pretty fast, so it's kinda complicated. Rocket fuel basically can give certain total change in velocity for your rocket. You can release that change quickly, or slowly. Let's say you have the fuel to accelerate 500m/s. If you accelerate at 9.81m/s^2, you won't rise up at all. After a minute, you've ran out of fuel. If you accelerate at 20m/s^2, you will only spend 25 second accelerating, but you gain 10m/s in speed every second. You'd reach about 3000 meter height at 25 seconds, having 250m/s in speed. After that, you'd slow down and get to about 6000 before falling down. And if you just blew up your fuel tank to gain 500m/s instantly, you would take 50 seconds to slow down to zero, ignoring gravity weakening. You'd reach 12,500m before falling down. This means, there is certain minimum change in velocity you need to gain to reach a specific height through use of fuels propelling you. To reach orbit around Earth, you specifically need to reach height of at least 100km. But for orbiting, that's not enough, you also need some 8 kilometers per second of horizontal speed to keep missing the Earth as you fall down. In cartoons, you could totally do this with two explosions, one at launch site propelling you upwards at roughly 1km/second, and then at the highest point of your trajectory launching you instantly sideways at 8km per second. But such explosions would destroy real world equipment and kill humans, so we need to do it slower, and therefore requiring more fuel. But we also don't want to do it unnecessarily slowly.", "There is a common misconception that rockets need to fly at escape velocity (42,000km/h or 25,000 mph) to escape Earth's gravity. This is only true if no additional trust is supplied, as if you were to shoot it like a bullet. When you can apply trust through exhausting fuel, you can move at pretty much any speed you like. As gravity gets weaker as you go higher, the escape velocity drops as well and you will be able to escape at much lower speeds. For fuel efficiency however, it is better to accelerate as fast as possible.", "The spacecraft will never break free of Earth\u2019s gravity. Gravity does get weaker as you get farther away, but a spacecraft in orbit doesn\u2019t come anywhere close to this. Instead, what they are trying to do is achieve orbital speeds so that they can circle the planet rather than fall into it. Gravity still pulls them down, but they are moving so fast laterally that they \u201cmiss\u201d the Earth rather than smack into it. Essentially, an orbiting spacecraft is falling \u201cpast\u201d the Earth every second, so that it always falls but never actually strikes the planet. And this is good news for us! If a spacecraft could actually \u201cescape\u201d the Earth\u2019s gravity by flying high enough, we would have no satellites, no moon, no ISS, nothing. It would all just fly off into space and never be seen again. As it is, they need to fly WAAAY farther to \u201cescape\u201d the gravity. Even then, Earth\u2019s gravity still affects it and the other planets in our solar system, even if only minimally. As for why they move slowly, that\u2019s called inertia. When you get in your car and press on the gas, do you immediately jump to 60 mph? Of course not. Your engine has to apply power to overcome your inertia and you accelerate over time. This is also good news. If your car went from 0 to 60 immediately, your body would basically be experiencing a 60mph collision. Likewise, if the spacecraft immediately leapt from zero to orbital velocity, the astronauts would die horribly. Be thankful we have inertia, because that acceleration over time is what keeps us alive.", "They don't break from earths gravity. Orbits are only dependant on horizontal velocity, and everything in orbit is still trapped (or parked) in earths gravity well, and every different combination or horizontal velocity and altitude gives a different orbit - *no matter the weight of the object!!* So to visit the International space station, you need to go exactly as fast as the station making your orbits identical, you cant just make your path go by the station and then drop off supplies when you pass by."], "text_urls": [[], [], [], []], "score": [23, 5, 4, 3]}}, {"q_id": "8es2rt", "category": "Repost", "title": "How does multi-colored toothpaste always come out in seperated colors?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dxy8gv3", "dxyc33i", "dxybkjz", "dxycfph", "dxyfk5g", "dxy9uwx"], "text": ["Wow. So many wrong answers. The colors are just injected in stripes then the tube is sealed. If you squeeze and smash the tube a lot the colors will blend. There are no smaller tubes inside, and there are no special nozzles. Here is a frozen tube that's been cut open URL_0", "So no one has addressed WHY the colors come out evenly. The stripes are indeed injected into the tube, which can be seen from tube cross sections. However the **reason** the stripes come out so well is due to the mechanics of **laminar flow**. This [video]( URL_1 ) is a good example of laminar flow in action. [Here is a video showing tube filling with laminar flow.]( URL_0 ) If you have any other specific questions just let me know! Source - Mechanical Engineer with fluid mechanics experience.", "[As you can see from this picture]( URL_0 ), all three colors are injected into the tube from the back, with the delivery nozzles configured to produce the pattern when extruded; the colors aren't separated by internal walls. it might seem that the external pressing and distortion might move the stripes around, but, due to the way that very viscous fluids flow, the stripes never really move around much from where they should be to produce pattern pretty closely to what it should be.", "To add on to u/AtomicFlx's comment, toothpaste in a tube would have a low Reynolds number. Basically this just means the flow would be *laminar*, meaning not easy to mix (not *turbulent*). This just related to its high viscosity and geometric constraints.", "In the factory, the differently coloured batches come through different pumps. The tubes go through the same attachement and everything is pumped into the final tube at the same time. This way, there is no room for the paste to blend. Here is a video with clear final tubes: URL_0", "I vaguely remember back in the 80s Aquafresh was one of the only or first to do the strips. I also remember the nozzle did have separate channels for the different colors. Obviously this not the way they do it today but I do remember the different channels and the way the toothpaste came out was separate streams. Could have just been the Pump version but I swear I remember the tube was the same. You can kind of see the separation in the commercials. [Aquafresh Pump]( URL_0 )"], "text_urls": [["https://i1.wp.com/beachpackagingdesign.com/wp-content/uploads/boxvox/6a00e54f0014bd8834015391a6d021970b.jpg"], ["https://www.youtube.com/watch?v=jFm8IxLwaoI", "https://www.youtube.com/watch?v=p08_KlTKP50"], ["https://i1.wp.com/beachpackagingdesign.com/wp-content/uploads/boxvox/6a00e54f0014bd8834014e8b9a87e1970d.jpg"], [], ["https://youtu.be/g9aD3BpxEAY?t=238"], ["https://www.youtube.com/watch?v=0fQqnjhDUbQ"]], "score": [3067, 226, 30, 26, 9, 8]}}, {"q_id": "8f81kd", "category": "Repost", "title": "How does money laundering work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dy1kiev", "dy1cduf", "dy1caw9", "dy1iday", "dy1iu73", "dy1j9qq", "dy1jdrz", "dy1klli", "dy1kvvv", "dy1cd2c", "dy1iboo", "dy1e7w3", "dy1jjv5", "dy1cee3", "dy1kqhq", "dy1mj0m", "dy1kqrw", "dy1mls6", "dy1lxw1", "dy1skkj", "dy1mlpk", "dy1olmx", "dy1nvqa", "dy1cdcf", "dy22819", "dy1txyd", "dy37vti"], "text": ["You stole $5 from Mom. Mom will definitely know if you buy something from it. You tell Mom you walk the neighbor's dog for the weekend. You walk the dog, earn $5. Tell Mom you earned $10 walking the dog.", "So let\u2019s say you have a good amount of illicit income like selling drugs, guns, sex trafficking, hitman, whatever. Now you can\u2019t really live a lavish lifestyle without throwing up some red flags. Like where do you get the money to buy these nice cars, houses, pay taxes on these things etc. what you do is you have a front such as a car wash, laundromat, somewhere you can really fake profits (it has nothing to do with actual cleaning of money, it\u2019s cleaning the paper trail). So how is the government gonna know if your laundromat has 10 or 50 customers each day? Basically you fake your dealings to have clean money to spend.", "To be short , someone makes a \u201cbusiness\u201d and claim to make **X** amount of money, but in reality they are making wayy less than that . Now you claim your drug money came from the business , so you have a clean paper trail accounting for the money you made .", "I saw some answers that are good but didn't see any I liked or that cover some of the other aspects. There are a few different types of money laundering, mostly depending on what you're doing with the money. The first is disguising the source of the money. This is used when you sell something illegal, drugs are a classic example. The money is converted into cash somewhere, the cash is then spread out to avoid triggering investigations, and then all that money is deposited in a centralized receiving account. Simple examples of this are things like someone else posted about the construction contractor that bills for work not done. Mid-sized examples use night clubs and bars, places where mark-ups can vary widely and cash is king, this allows the club to mark as sold thousands of drinks, entries, or sometimes even entire full night events that never actually happened. I expect that right now there is a rise of using cryptocurrencies to do this because the volatility can hide a lot of bad things. For large accounts the money generally goes international using a large number of international transfers to hide the money source, the money then goes through a combination of the large and small areas to reach the goal. For even larger amounts you build something. Say a large building or complex of buildings in a really tacky gold color. Everything is built super cheap, but for some reason buyers pay over market rate, and your investors somehow make massive returns. You then brand yourself as a real estate genius thinking you're amazing at making deals, when really you're just the patsy. The second reason is to hide the destination of the money, this is actually how some of my clients paid me, even though everything I did was legal. For this the business will often generate a fake theft. \"Someone\" skimmed the money coming in, embezzling it, the money finds it's way into a duffle bag, and that duffle bag of cash is used to pay people. This is the same basic method that is used to pay people under the table. For larger amounts a charity is setup, the company makes donations and the charity sends the money along. In my case I eventually worked through a family trust account, my clients hired the trust, the trust paid me, this is so much easier than trying to find a way to deposit a duffle bag full of cash without raising suspicion. Since my work was legal I didn't bother laundering, but my clients thought I was laundering through the trust. The third category is simply to disguise what you're actually doing, and this can often be legal. Maybe you need to pay a pornstar to not tell everyone you like to be spanked with a magazine. For this you generate a false business. An intermediary consultant is hired, the consultant is paid an exorbitant rate, usually many times the normal going rate for their work, the extra is paid out. This leaves clean hands for the person paying and the recipient knows exactly where the money came from. Like I said this can sometimes be legal, sometimes it isn't.", "A lot of people are mentioning businesses, but that's usually for low-level, small time crime. Let's say someone makes $100k, but also makes $50k illegally somehow on top of that (maybe selling something illegal on the side), this is common with EU truckers for example, who often smuggle cigarettes on top of their normal stuff across borders. Now this $50k is 100% illegal income, they can't really pay taxes on it otherwise the government might ask questions (how did you make $150k when every other trucker made $100k?). You can't really spend the $50k, because again, the government can be like (you made $100k, how did you spend $150k last year?). So some of them open up mostly sham businesses that they don't care about, like a small coffeeshop, and then claim it makes $50k when in reality it makes way less. A single coffee shop making $50k is completely reasonable and nobody will ask questions. Boom, now this truck driver can use his illegal money. However, for wealthy, more impactful people, it's different. Somebody worth millions of dollars, suddenly opening up chains of businesses and ensuring each one of them lie about their income is a nearly impossible thing to pull off, especially in the EU. So, one way wealthy people money laundering is through 'fake' purchases that don't raise suspicion. Let's say I'm selling you $5m worth of illegal goods. You can't give me that money in cash as a gift, otherwise I'd have the same problem as the trucker earlier. So I sell you something else. Like a stupid fucking painting that's worth nearly nothing. And you buy it. Boom, you get your goods, I get my money, and the stupid fucking painting was the middleman to make it a legal transfer of money. You can replace the painting with anything, even businesses or houses or whatever. (I'll sell you the title of this shitty, crumbling business for $5m). There's other ways as well, including putting the money into Bitcoin, withdrawing it in foreign banks that have little regulation, claiming it came from investments, etc.", "You are rich drug lord and earn millions of dollars. You want to buy a house and fancy cars, but you need to pay through a bank. You can't deposit more than $10000 without drawing suspicion on where the money comes from. So you start up Mattress Firm, a scam mattress business with rip off $3000 mattresses that sell to 1 out of 100 suckers. But you tell teh IRS that you sell hundreds of mattresses every month, making millions. Now you deposit those millions, thats where they came from!", "There are many ways, but many people have covered them. Sometimes, where I'm from, it's as simple as putting the money into poker machines, redeeming the cash and then claiming you just get lucky via gambling. It can be super hard to prove otherwise.", "Imagine a scenario where you were given a large sum of money, but it wasn't a gift from a rich uncle or something. Or, more likely, you find yourself having to handle a large amount of money on an ongoing basis [ex. you're a spy, or sell drugs, or something]. This works whether someone is paying you [drug lord scenario], or you are paying someone else [you screwed a pornstar and are buying their silence]. The mob made this a science, though there are a lot of ways to do it. * Step 1: spend a few hundred setting up the paperwork for a business selling food, or doing drycleaning, running a casino, or renting apartments. Or whatever, but those are the easiest. * Step 2: hire a buddy who's in on the game to manage the business for you. Cut them in for a percentage. * Step 3: fake sales. If you bought an apartment building, set up fake accounts in a few of the units, rent the rest for real. Move the empty units around occasionally. If unit 1 is empty right now, move someone in after the person in unit 3 moves out. Keep unit 3 empty in real life, but occupied on paper. You can even furnish it and throw things around once in a while if you want it to look occupied. * Step 4: Ditto for a pizza joint, casino, or used car sales. A few real clients and a lot of fake customers. It helps a lot if you're bad at paperwork and records, or if no paperwork is necessary. * Step 5: A laundromat is useful because there isn't even much to track in terms of inventory, if an investigator shows up to ask questions you just say \"the customer brings their own soap, I just keep the machines running!\". A casino is useful because large amounts of cash comes and goes, and there is no way to prove a particular round of poker did or did not happen--it's just a line entry saying \"so and so lost $5000\", if that. * Step 6: Take your real money from your fake clients that was earned via a real business to the bank and call it good. Vary the amounts slightly, but keep them within the bounds of what an actual business of that sort would have to do in terms of cashflow in order to stay open, but not so much that it looks suspicious. * Step 7: count your Benjamins, pay a little tax, be the rich uncle.", "Ok suuuper simplified. There are three phases: Placement - getting rid of dirty cash by depositing it in an account, taking it to a casino, buying money orders etc. Layering: this is what most people think of when they think laundering. In this phase you're trying to obscure the source by converting the forms of monetary instruments. You could open up a front business, or even buy a life insurance policy, cancel during the trial period and ask them to mail you a refund check that appears clean. Lots of things you can do here. Integration: by this point it's hard or impossible to tell dirty money from clean, so you go ahead and buy yousself something nice. Maybe a condo or cigarette boat.", "There are different schemes for laundering money of varying complexity, but the basic idea is you take money that you obtained illegally and pass it around to make it legitimate. A simple way to do this is buy a business and use the dirty money to make purchases at that business. Then if the IRS asks where you got that money, you can show them your business and that businesses finances.", "Just to add on a bit more that people didn't cover If you have a ton of money and decide to use a mostly cash business to make it seem legit, you can still get caught. For example, if your laundromat's utility bill for electricity or water is extremely low compared to the booming business you're supposedly doing. Or the water bill for your car wash is low or the same as other car washes, and you claim to take in a ton more money, without having high ass prices Or your pizza joint/sandwich shop has few expenses for bread, toppings, etc., but supposedly is selling all these pizzas made from nothing Or they check with your supplier of dough, and see that your figures are wildly different Or your bar doesn't buy much alcohol, yet somehow sells a ton of drinks. They aren't that watered down! So while the process is simple, you can still be caught easily too.", "Just another more detailed example, I know a person who does construction cost estimating who had done small \"washes\" for people. (Laundered small sums.) If they have 5k, he might bill them for a few jobs he estimated, which is a job that only involves labor, and if he was ever questioned, he has legitimate estimates he could produce to show as the work he performed. He has a business set up as his own company with himself as the sole employee which isn't strage for an independent estimator. He deposits the checks he received or cash as payment for the job, accounts for it as business income then slowly over the next few weeks withdraws money from his business account as his pay or business expenses or whatever. Eventually he gets the cash back and returns it minus his cut. Edit: gives the cash back either as payment for services or some other business transaction.", "So in breaking bad they laundered money by making sales of carwashes that never happened, up charged ones that did but have them the basic carwash. All these sales turned the drug money into clean legit money.", "You take an enormous amount of illegal cash and spend it at a business you own. The traditional business of choice was a laundromat (hence the name), but any heavily cash based business works. They have too many customers that just hand over cash to be expected to know where it all came from so it is the perfect place to make your illegal money suddenly appear in a legal way.", "Money laundering is taking dirty money and making it clean. The idea is to hide the dirty money as \"legitimate\" income from a clean source. Pretend you are a criminal trying to launder your money. Open a legitimate business. Don't waste your money on advertising, quality equipment, or a good location. You only need it to be good enough that it attracts enough customers to make it seem like you're not doing anything suspicious. Once you've got that covered, you start claiming that you're doing more business than you really are. You claim more customers than you actually got, with the income you claim is from these fake customers is in reality from your illicit doings. Now you've got clean money that you can give to a bank, use on a credit card, or (and this is a very important step) pay your taxes. Al Capone wasn't convicted of most of his crimes, it was the tax evasion he went to prison for.", "Money laundering is disguising where you get your money from. Say you grow drugs and sell them to a dealer. You live in a fictional world where you, the only drug farmer grows all the drugs and sells them all to a dealer, who is the only dealer and sells them all to customers. So, you're making a fuckton of money, and according to the government, don't have a job (or if you have one, you make $50k a year and spend 50 million). The government won't be happy if they find out, because you're not paying income tax, and also committing crimes. You need to make it look like either A: you're not spending the money that you're spending or B: you're getting their money from a legitimate source, like a job that you have or a business that you own. The easiest ways are to either open a bunch of fake businesses, and then have a lot of fake transactions as income, or to just move it around in really complicated ways until nobody can see the original source. The second method is easier to explain. Checks and wire transfers clearly show the original bank and account, so a dedicated law enforcement official can backtrace them with a warrant (or not with the patriot act). So, you need a transfer that they can't backtrace and also can't say is illegal. Typically this is either a wire from a country that won't cooperate and tell them who sent the money, cash deposits, or money orders deposited and paid for with cash. This is why the US government requires banks to fill out a currency transaction report for any customer who exchanges, deposits, or withdraws more than $10,000 in cash in a given day. It's also why people scrutinize transfers from the Cayman Islands and Switzerland so much. The cash deposits thing is obviously much simpler, a cash deposit is inherently untraceable (assuming you can't just match amounts). This is why some banks (like Chase/JPMorgan) require you to give them ID when you deposit cash into your account, or just won't let you put cash into someone else's. The first method is more difficult. Say you open a chicken shop. You have 10 customers per day, who spend $10 each on a bucket of chicken. Well, you're a money launderer so all of a sudden, your accounts book says that each client spent $100 on chicken. Or, maybe it says you had 1,000 customers who each spent $10. Either way, you are now taking in cash that you didn't actually earn from chicken, and did earn from drugs. Since you own your chicken shop, you pay taxes and that money is now yours to do what you want. Or, you can then do method one to be extra sure the feds can't find out how you make your money. Hope that works guys, I tried. I'm a bank teller so I can answer any questions you have about currency reports or some basic questions about the other parts of this.", "There's a gas station across the street from me that has literally never changed it's gas price since I moved here in August. Never see anyone buying any snacks or drinks there. Sometimes I buy cigarettes but like 50% of the time they're just out of them. Totally convinced it's a front.", "Financial crimes investigator here. There are three main stages to effectively launder money: placement, layering, and integration. Basically, dirty money stemming from drug sales, prostitution, illegal gambling, etc. is deposited into a bank account as cash. Deposits will be kept below $10k in order to circumvent the filing of a Currency Transaction Report. The money will also likely be deposited at many different bank branches using several different individuals (\"smurfing\") in order to avoid suspicion. That money will then be moved to a number of different deposit and investment accounts and can also be used to pay bills and fund regular living expenses. After the money is moved to external accounts, it can be withdrawn again as cash (clean bills from a bank branch/ATM) to purchase more drugs. Additionally, debit cards and personal/cashier's checks can be used for further living expenses as well as the purchase of luxury items like cars and property. If the launderer is smart, the banks where his money is stored will never see the whole scope of the activity that's occurring and will likely not look into his activity too closely.", "Is there a good free introductory course on forensic accounting?", "You get money from something illegal, the tax man sees your money and says \"hey, where'd you get that money?\" And then you're busted and get in trouble. But if you have a business, you can lie and say \"tax man, I got this money from my business!\" No more trouble. But tax man is smart. Tax man knows all the businesses and how much money each one usually makes. He says \"Show me every single time your business made money, and from where, and ill add them all up. If there's lots left over, you're in trouble\". So you need to lie more, and write down people who didn't buy things at your business, so you can tell tax man that the extra money you got from illegal stuff came from them. But if you tell tax man your lemonade stand made sixteen million dollars last month, he can figure out that you lied to him, and you still get in trouble. So you need to be smart too. You need to own businesses that can make lots of different amounts, a few thousand one month, many more thousand another month, even of you didn't do anything illegal. Tax man might believe you if you say the money came from there if it's a believable amount. But what if you do LOTS of illegal stuff and make LOTS of illegal money? More than any lemonade stand would ever make? Well, you need to buy lots of businesses with lots of different money amounts, an write down lots of imaginary people in all of them. Sometimes tax man will try to find the imaginary people, so be careful. But wait, what if you don't HAVE lots of businesses to write fake people in? You only have a lemonade stand, and you did SO MUCH ILLEGAL STUFF that you know tax man is going to get you and tell the police, what can you do? Well, there are some big smart people in suits who already own lots of businesses and are very very good and writing down fake names, you can go to them and say \"please make my money look like it came from your businesses\" and they will say \"ok, but we get to keep some of it\". And that is money laundering. This is why [HSBC bank are bad bad evil people]( URL_0 ), because they are some of the big smart people in suits who do this to help very nasty people who do nasty things to nice people.", "The entire province of British Columbia has been used for money laundering. Casinos, real estate, supercars, it's stuff bought with grey- or black-market cash, no questions asked, and it's unclear at this point how complicit the former government was in the expansion thereof. URL_1 URL_0 URL_2", "If you're actually looking for an easy way to clean your dirty money OP, then I recommend gambling with it. Most slot machines are programmed to provide a set return over time (usually 70 to 80c per dollar spent in them, which is why they're so profitable since the house is essentially making 20 to 30c per dollar gambled) and while you're ultimately losing 20 to 30% of your money, you are able to claim the rest as legitimate winnings.", "Not a full answer by any means, but I can give a quick and easy example which I have first hand experience with: I used to work in a high street bookmakers (a sports betting shop in the UK, which are very common here but as I understand it not very in other countries). We would often have the following problem: People would come in and put dirty money in the betting terminals, place a few very low risk bets to feign legitimacy, and then print off a value ticket and claim it at the counter. This way they now have clean money from behind the counter, as well as a receipt to \"prove\" where it came from. It was a bit problem for a while, and also very difficult to spot at times (though, very obvious at others).", "Image finding a ton of money like 5 million dollars. If you were to go spend it Uncle Sam would notice and start wondering where you got it and why he didn't get his cut. So to avoid questions from Uncle Same you would open a business and take your dirty money and put into the business as if people were buying stuff even if you haven't had any customers. So that there will be a paper trail, and when Uncle Sam looks he sees you have a business and it makes money.", "So, let's say you tried stealing fractions of pennies from a company by always winding down and depositing the remainder into your own account. Now, your software working buddy misplaced a decimal point (always happens) and you have a very noticeable chunk of money. Now, you could ask an ex crackhead who's selling magazines about money laundering. No info there. You could choose to give the money back. Or you can ask Reddit and learn to launder. Ideally, you'd want to have this setup before you come into money that needs laundering. Using a service based business allows you to conceal actual sales and costs. Saying that you made more legally allows you add cash flow from illegal transactions into a legitimate business.", "Hey I did two dissertations on money laundering, I\u2019m gonna keep it as simple as possible. The goal of money laundering is to place cash in the financial system with the goal that that illicit money will emerge clean. Actually, part of the reason why it is called laundering, as years ago laundromats were used frequently as a front, because they were a cash incentive business. (Fun fact) Anyway, so there\u2019s three stages of money laundering; placement, layering and integration. Placement: placing the money into the financial system. Layering: this is essentially creating complex transactions to create distance from the original source of money. Some methods of this include making small deposits of money in various account. Integration: money has emerged clean into the financial sector. This is the most simplistic version of money laundering that I can explain to you. But with developments in crypto currencies and mobile e-money the face of money laundering and terrorist financing is changing. Any other questions please feel free to ask and I\u2019ll do my best to answer them.", "Money laundering is when illegally obtained money is put through various cash flow channels to make it appear as though the money was legally obtained. For example, a drug dealer cannot deposit $50,000 per month into a bank account each month without incurring a severe risk of being caught. For example, the bank is required to report certain money transactions to the government. The bank is required to report interest on the account to the IRS for tax reasons. When it comes time to file taxes, the IRS will notice a person who is making $600K per year, and interest on that money at a bank, yet receives a tax form from that person indicating that the person is not employed (hard to say you're a drug dealer without going to jail). So, one way that drug dealer might deal with the problem is as follows: They might, for example, setup a neighborhood pizza shop. The dealer will setup a legal company, set himself as the owner of the company, and \"pay\" the pizza business with drug money (as if it was revenue from making and selling pizzas) to make it look to outsiders that the pizza business was selling pizza and making money. Then, the drug dealer could legally pay tax on that drug money, once it appears as revenue to the pizza business, and then pay himself a salary with the profit. Once illegal money (from drugs) now looks like revenue to a legal (and thriving) pizza business. The drug dealer's salary is explained, the source of the money is explained, and the drug dealer can fly under the radar without the IRS immediately seeing something shady. The drug dealer now has an explanation for his expensive house, car, and other goods - he has a successful pizza business."], "text_urls": [[], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], ["https://www.google.co.uk/amp/s/amp.theguardian.com/business/2012/jul/17/hsbc-executive-resigns-senate"], ["https://globalnews.ca/news/4087440/money-laundering-crackdown-bc-budget/", "https://www.theglobeandmail.com/news/national/globe-investigation-into-money-laundering-in-bc-real-estate-will-lead-to-new-rules-ag-says/article38018921/", "https://www.thestar.com/business/2018/03/28/vancouver-supercar-dealerships-next-target-in-bc-money-laundering-crackdown.html"], [], [], [], [], [], []], "score": [21250, 6382, 1383, 775, 706, 196, 107, 56, 49, 27, 27, 18, 16, 16, 13, 13, 10, 10, 9, 9, 4, 4, 4, 3, 3, 3, 3]}}, {"q_id": "8freim", "category": "Repost", "title": "Why does the urge of going to the bathroom drastically increase the closer you get to the bathroom?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dy63vlx", "dy6it7y", "dy6bbe8"], "text": ["It's a trained psychological response. We have trained ourselves that the toilet is a safe place to let loose. It's the same reason people will fall asleep if they lay down on a bed, even if they are not tired.", "It's behavioral and has to do with the minds awareness. In adults, some part of the mind is always aware of when it is appropriate to use the restroom, and when it's not. This keeps us from wetting the bed, and other awkward social situations. When you know you're about to get relief, the body starts to relax and commit to it, and there is no turning back. You probably read about Pavlov, and his work with dogs, when you were in school. When the body involuntarily performs an action, in anticipation of something, we call this a Pavlovian response. People usually talk about salivating at the thought of food, but I find it funny that thinking about sex, and the resulting 'ahem' changes that result, are in that same realm. An interesting thing is the same thing happens with breathing and free divers. The most dangerous time for people who ocean dive without oxygen, is when they are about to break the surface. These people drop off into the water with a weight and sink great distances, then release the weight and swim back to the surface, all on a breath of air. The danger, is that if they stay down too long, as they get close to the surface, the mind anticipates the air and it becomes increasingly hard to prevent taking a breath, and people can drown as they start breathing water before breaking the surface. There is also anecdotal evidence that people who learn to urinate in unusual places, also have problems with urgency when they are near those places. For instance I read about a person that used to pee in their dresser when sleeping, and even when awake, they would have a similar sense of urgency when near the dresser as they would a bathroom in spite of not wanting to consciously urinate in it.", "I realized that it is a trained psychological response, so I think about something else important as I get closer to the bathroom, this makes the urgent need to pee go away. Then when I am standing before the bowl, I allow myself to remember that I really need to pee, and all hell can now break loose."], "text_urls": [[], [], []], "score": [23, 6, 4]}}, {"q_id": "8fvkcr", "category": "Repost", "title": "The difference and jurisdiction between police, sheriffs, state police, FBI, highway patrol; who handles what?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dy6suky", "dy6t8ii", "dy6syr3", "dy6t5p3", "dy7cjd0"], "text": ["Very simply: Police = City Sheriff = County State Police = State =P Highway Patrol = State highways, interstates. FBI= Country Wide - Federal crimes", "Police have Jurisdiction within a city or town. Sheriff's Departments have jurisdiction within a County. That technically includes cities though they normally defer to the city level police and focus their actions outside of city limits and in towns too small to have their own police, as well as crimes that happen both inside and outside of a city or in multiple cities within a county. State Police, Highway Patrol, etc have jurisdiction within an entire State. Some departments are focused on specific things, such as highway patrol being focused on traffic safety on highways. Others like State Troopers or the Texas Rangers deal with crimes that happen in multiple counties and deal with the transfer of prisoners across county lines. National level police such as the FBI, US Marshals, Border Patrol etc are also fairly specialized. They have jurisdiction in the whole US but have specific jobs. Border Patrol, or ICE deal with immigration and customs imports into the US. US Marshals deal with witness protection, transport of prisoners across State lines, deal with crimes on Federal lands such as national parks, and deal with some crimes on Native American Reserves. The FBI deals with crimes that happen in multiple States, specialized cases such as serial killers, and the like.", "And aren\u2019t sheriffs in the US elected officials (I\u2019m Canadian - we don\u2019t have sheriffs as such)?", "It's area based mainly.. Police have jurisdiction inside the city limits.. Sheriffs Deputies have jurisdiction inside the county.. State and then so on.. but yes, some small towns don't have a Police force so the county has jurisdiction.", "Many think that the US policing system is a mess, and without a doubt I would say it\u2019s complicated but very orderly in that every jurisdiction has its own entity. Others have mentioned that Australia is much simpler, with Federal police, and then state authorities taking care of local policing, ambulance and fire. Very clear cut. In Canada it\u2019s a bloody mess. At the federal level you have the RCMP, and various other agencies for specialized areas, though the RCMP often have jurisdiction in these areas too, ex. CBSA is our customs and immigration agency, yet RCMP has jurisdiction over patrolling the physical land and sea borders. At the provincial level, you also have the RCMP taking care of provincial crimes ONLY if said province chooses to opt in for RCMP service. 3 provinces opted out (Ontario, Quebec, and Newfoundland) and as such have the Ontario Provincial Police, Suret\u00e9 Qu\u00e9bec, and the Royal Newfoundland Constabulary taking care of their own provinces\u2019 crimes. On the municipal level you again have the RCMP but ONLY if the municipality has opted in. Otherwise, municipal police services can be organized (e.g. the Toronto Police). But municipal forces derive their authority from the Crown at the provincial level, giving them authority anywhere in said province. In the territories up North, sovereignty/border integrity is again taken up by CBSA and RCMP but also with the Canadian Army Rangers - essentially dudes with red hoodies, hatchets and Lee Enfield rifles. On Indian reservations, some have Indian police services and others have RCMP - unfortunately I don\u2019t know the distinction. While I\u2019m not very knowledgeable about this, I have heard that some treaty lands have the ability to refuse entry to federal authorities. In other words, we need some help from the UK and Australia!"], "text_urls": [[], [], [], [], []], "score": [155, 36, 8, 5, 3]}}, {"q_id": "8g51a6", "category": "Repost", "title": "How does UV light kill viruses and bacteria?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dy8zvc5", "dy92v2o"], "text": ["UV rays can create thymine-dimers in your DNA which if done in high enough quantities, will make your DNA unreadable. When this happens, basically your cells' instruction manual gets peices of it scratched out. So when this happens to bacteria, it's like getting a sunburn on every cell in your body, being that you are a single celled organism.", "For viruses - viruses don\u2019t retain water very well, so a UV boop usually means a virus that\u2019s so low on water it\u2019s basically useless. Bacteria keep their water to a better extent, so they usually die of DNA mutations, as the other guys said. Eventually, all the proteins are weird and the bacteria dies from failing cellular processes."], "text_urls": [[], []], "score": [16, 4]}}, {"q_id": "8gjv9x", "category": "Repost", "title": "if a bullet is shot directly into the air, can the results be fatal if it strikes a person in the head on the way back down?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dyc8k4s"], "text": ["Yes, people die every year from stray bullets. It\u2019s honestly pretty tragic. At terminal velocity coming back down, bullets are still very deadly."], "text_urls": [[]], "score": [6]}}, {"q_id": "8gva0o", "category": "Repost", "title": "How come when it\u2019s hot out, and your turn your AC on to say, 68 degrees, it feels good.. but when it\u2019s cooler outside, and the AC is still on 68 degrees, you feel cold even though the temperature in the house has been regulated?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dyey38o"], "text": ["It has to do with the humidity. When it's hot, the humidity is usually higher, making your body work harder to regulate it's temperature by trying to cool. Turning in the AC removes some humidity from the air, making it easier to be cool. When it's cold, the humidity is usually lower, making it easier for your body to cool itself. In these cases, you body then tries to wash itself."], "text_urls": [[]], "score": [4]}}, {"q_id": "8he6hv", "category": "Repost", "title": "Why is the sky blue during the day when space is black?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dyj3a0w"], "text": ["A clear cloudless day-time sky is blue because molecules in the air scatter blue light from the sun more than they scatter red light. When we look towards the sun at sunset, we see red and orange colours because the blue light has been scattered out and away from the line of sight."], "text_urls": [[]], "score": [19]}}, {"q_id": "8heqtf", "category": "Repost", "title": "- Why do almost all people with down syndrome have the same facial structure?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dyj7ss5", "dyjbjo4", "dyjnb4c", "dyjiqku", "dyj80cb"], "text": ["Genetics determine appearance. If you have a group of people who all have a similar genetic pattern it stands to reason that they would display similar characteristics. Genes present within the 21st chromosome result in a person with trisomy of that chromosome (third copy) having those physical traits. It's not just the facial traits either, Downs also causes a much higher rate of congenital heart defects.", "Can someone explain to me where to extra chromosome comes from? Also is it a chromosome or a chromosome pair? Does there have to be both a sperm and egg with an extra chromosome or is it a mutation during gestation.", "Someone explain to me: Can people with down syndrome have offsprings? If yes, would the child have down syndrome too?", "I am not sure how, but the chromosomal trisomy somehow affects either the differentiation or migration of neural crest cells. These then generate a number of structures troughout the body, but mainly nervious tissue (they are vital for development of the brain), pharingeal arches (which derivate into jaw; incus, malleus and stapes; hyoid apparatus) and several skull bones and cartilage (yes, this inclues facial bones and cart, giving their distinctive facial featuees). Additionally, neural crest cells also originate a heart valve (dont remember which) which tends to develop abnormally in downs syndrom patients and is partly why they seem to have more heart problems than usual. TlDR: abnormal neural crest cells.", "It's an aspect of the condition. The extra copy of chromosome 21 or parts of it in the people with down syndrome results in significant changes to body and mental growth and function, because its directly changing the way their DNA goes about creating and directing all the parts of putting someone together."], "text_urls": [[], [], [], [], []], "score": [635, 71, 55, 13, 7]}}, {"q_id": "8hrsu6", "category": "Repost", "title": "The Iran Contra scandal.", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dym0x7l"], "text": ["The US used to basically own the Iranian government (The Shah was very \"friendly\" to the US). In 1979, Iranians had a revolution, and deposed The Shah. They replaced him with Ayatollah Khomeini. When this happened, they took US citizens as hostages. Because of that, the US embargoed Iran (not to mention sold many weapons to Iraq so they could fight Iran). You couldn't trade with Iran. Period. Except the US government (under Ronald Reagan) didn't like the government in Nicaragua. It was very leftist (Socialist). They wanted to support the Contras in Nicaragua so they could overthrow the government (The Sandinistas, who had overthrown the previous government in Nicaragua in 1979). So the US government sold weapons to Iran and funneled the money to the Contras in Nicaragua (who failed to overthrow the Sandinistas). This was totes illegal! Luckily, President Reagan was super old, and decided to tell everyone that he didn't remember ANYTHING. Oliver North was thrown under the bus (he volunteered) and blamed for it instead of the Reagan administration."], "text_urls": [[]], "score": [5]}}, {"q_id": "8i4fpc", "category": "Repost", "title": "How come it gets harder to pick up a new language as we grow older?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dyotlgg", "dyp1bos"], "text": ["It's not. That's a myth. What IS true, is that your ears have closed themselves from sounds that aren't in the languages you learnt when you were a child \\(usually your mother tongue, but if you had bilingual parents for instance, it could be several languages\\). There IS a way to open your ears \\(=brain\\) to the new sounds : being able to pronounce them. The same phenomenon happens in music, when at first you're unable to hear articulations, but when you can do them yourself you become able to identify them by ear. The PROBLEM here is that 99 & #37; of language teaching puts the emphasis on grammar and not on pronunciation, so you DO struggle, but it has nothing to do with your age and all to do with the way you're taught those new languages.", "There's a region of the brain responsible for picking up your first language(s). Learning a language is pretty much an instinct in Humans, but that instinct (and that region of the brain) go away when you're fairly young. It's still possible to learn languages, but it is more work since that specialised region has done it's original job and doesn't work that way any more."], "text_urls": [[], []], "score": [10, 3]}}, {"q_id": "8ipxat", "category": "Repost", "title": "Why does rubbing your eyes cause flashes of random colors?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dytnsdz"], "text": ["I'm sure someone will be able to explain it better than myself, but I believe it has something to do with your optic nerves misinterpreting the pressure as visual stimuli, so your brain tries to make up what you're seeing. Edit from Google: Phosphenes are most commonly introduced by simply closing your eyes and rubbing them or squeezing them shut, tightly; generally the harder you rub or squeeze, the more phosphenes you'll see. This pressure stimulates the cells of the retina and, thus, makes your brain think you are seeing light."], "text_urls": [[]], "score": [5]}}, {"q_id": "8iu6l0", "category": "Repost", "title": "why is it so hard to find a cure for cancer despite the money that has been poured into cancer research?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dyun80k", "dyun4o7", "dyunmlc", "dyunjn4", "dyutxod", "dyuxytl", "dyupiig", "dyuvm63", "dyusxdf", "dyuywxi", "dyunpb8", "dyun5q2", "dyuyob7", "dyuof19", "dyuxys1", "dyuwwzj", "dyuynle", "dyuzdh9", "dyuvto2", "dyv085l", "dyuzkax", "dyuy5k4", "dyvkxiq", "dyvgalv", "dyuxcfh", "dyv793x", "dyuynej", "dyuvm1u", "dyuw7n2"], "text": ["Because there are many, many cancers. Saying 'a cure for cancer' is about as reasonable as saying 'a cure for physical injury'. There are as many different kinds of cancer as there are ways and places that a person could be cut, bruised, broken or burned. The research, tests and trials are constantly discovering, testing, and bringing into full production treatments for different cancers. As a result, the outcomes for people are getting better all the time. Some cancers that were a death sentence just a few years ago are now routinely cured, and as we gain deeper insights into the genetic causes, this can only get better. But it will always be an area where more research will be needed, as there will always be less common cancers that need new treatments, or more common cancers that could have better treatments.", "Because cancer is not a disease like smallpox or anything else we've cured so far. It's your cells that turn into cancer cell because of whatever reason so there is nothing to cure from the outside. Oh and there are a lot of types of cancer so that makes it even harder", "Because it's your own cells going haywire and taking over your body. It's like trying to stop an enemy that hides among innocent civilians. Yeah, it's easy to kill them if you have overwhelming firepower, the hard part is doing so without killing all the innocent bystanders. The innocent bystanders, in the case of cancer, being your healthy cells you need to survive. The methods we use to kill cancer, chemotherapy and radiation, also kill your healthy cells. It's hard to find a method which distinguishes between healthy cells and cancerous cells, whereas with something like a bacterial infection, you just flood your body with chemicals (antibiotics) that kill bacteria without affecting your human cells. Because of slight differences between our cells and bacteria cells, there are chemicals that kill bacteria while leaving us alive. There are slight differences between your healthy cells and cancerous cells, such as the cancerous cells being slightly weaker than your healthy cells, so they can be killed with a certain concentration of poison that leaves your healthy cells alive (chemotherapy). If the cancerous cells are all located in one spot that can be operated on, you can simply cut out the blob of cells, or target it with radiation. Unfortunately, there's lots of types of cancer, and sometimes they aren't weak enough to be killed by these methods or they've spread throughout the body and can't be killed without killing all the healthy cells, or originated in an inoperable area where surgery or radiation would kill some vital organ.", "Because * It's parts of your own body killing you by doing a perfectly normal and desired thing *too much* - so your immune system usually won't' help, and chemicals that destroy cancer cells will generally also destroy healthy cells and kill you. * if you don't get every single cancer cell, it will just gro again, possibly much worse if you did something where the surviving cancer cells got into your bloodstream and spread around your body. * Cancer is really not jsut one disease, it's hundreds, because different kinds of cells behave quite differently when they become cancerous, and even in a single tumor you can often find different strains that are effectively separate diseases.", "A cancer cell is like a car that just keeps going and won't stop. So we want to make this car stop, right? Maybe we fix the brakes, maybe the problem is the brakes aren't working, so let's design a new brake system to install on the car. Except, how do you design one that fits EVERY car (BMW, Toyota, Chevrolet)? You would have to design one for every car. So we do that, and we fix the brakes, only to discover that the gas pedal is the problem, it's giving the engine full throttle despite the brakes, so we go back to the drawing board, and we come up with a fix for the gas pedal, again, requiring a different one for every car. Only to find out, from travelling so fast, the car is all bent up, and hood is pressing down on the wire to the gas pedal, so our new system isn't working. The idea of a \"universal cure\" for cancer is the same as the idea of a universal mechanical part that would fix any car. In the same way that we can brand a car as \"BMW\", \"Toyota\", \"Chevrolet\", and then as \"1992 model\", \"2007 model\", and then \"Sport ZX trim\" or \"SS V8 model\", we can do that with a cell - \"lung cancer\", \"neuroendocrine lung cancer\", \"ER+ PR- breast cancer\". In the same way that each car would need a special part, each cancer would need a special drug to fix the particular thing that is broken in that cancer cell. Beyond that, each PARTICULAR car has its own story and its own unique pattern of damage, same as a cancer cell, so even the specific part for that specific car model may not actually work in that particular car given its damage. The mutations in every person's cancer, will be different from another person with what is called the same type of cancer. On top of all that, we don't have 1 broken car, we have 1 billion of them, and the ones that we failed to fix, they reproduce and generate new, differently broken cars. Some of the exciting stuff they are doing with cancer now it's going to the immune system, the auto mechanic, and telling it to destroy these cars. The cars are telling it \"hey, stay away, it's all good\", so we try to mess that up. These are, for example, PD-L1 inhibitors in lung cancer, and they can work miraculously, but they don't always work (since every cancer is different), so people can once again point their finger and say \"no cure\" Some cancer research money goes into better understanding the cancer (the blueprint of the car) to understand which parts are malfunctioning. That research, one hopes, will lead to a new type of car part that can fix that problem. We are also doing a lot with this immune system stuff too. But the war on cancer, it's a game where we are slowly whittling, whittling, whittling, collecting parts, building an arsenal. We likely won't ever have \"the cure\" but rather slowly increasing chances of survival year after year. Most drugs now, your hair doesn't fall out. Back in the day, the first generations of cancer drugs, your hair falls out because the stuff we were giving just knocks out any cell that reproduces a lot - such as your hair follicle cells. With the car analogy, this is like we put spike strips on every road for any car going over 40 mph. So this knocks out our broken cars well enough, but the normal working cars going 45 mph also hit the strips and get knocked out too. Because these drugs or \"replacement parts\", they don't go on just the broken cars, they go on EVERY car - they effect every cell in the body, not just cancer cells.", "You'd be shocked at how much money raised for cancer actually makes it to research. Most charity money funds the charity, not the cause.", "Cancer isn't a disease, but a *type* of disease. There are many different types of cancers, and all of them have their own name - you may have heard of leukemia, melanoma, and/or common names like cancer of the colon, skin, eye, brain, etc. Finding a \"cure for cancer\" means finding a cure for each and every different type of cancer (or, possibly, a way to prevent it from occurring to begin with.) Cancer is what happens when cells malfunction in a certain way. You see, the cells in your body reproduce by splitting into copies of itself. This is how your body grows and heals. The copying process itself isn't perfect, and small mistakes happen all the time. Mistakes made when copying stuff like proteins or ribosomes or whatever don't matter that much - the bad copy doesn't work, but that's fine because the DNA master file is still undamaged and a new copy is made from that. When a mistake is made while copying DNA, or the DNA is damaged by radiation or something, the problem is a bit more serious. Fortunately, your body has several mechanisms to fix this sort of error - there are special proteins that can sort of \"quick-fix\" tiny bits of damage - they sort of comb small knots out of the strand. For more serious damage, more complex sort of processes exist - I'm not going to go in to too much detail, but every cell has multiple copies of the same code - two on each strand, for a total of four on each chromosome. These processes can replace damaged bits of code by making copies of the undamaged versions, like restoring from a backup. There are some types of damage that can't really be fixed, though, not correctly. There's even a self-destruct function built in - when too much damage occurs, or certain other conditions are met, cells die in a process called apoptosis. Cancers happen when cells stop self destructing, and continue growing. Different cancers exist because there are so many different types of cells in the body, which even normally all act differently in order to perform whatever function the body needs them to do. Their rate of growth and replacement, how they move through the body, and the sorts of conditions and nutrients that help them grow all play a part in how they behave when they become cancerous. Neurons, for example can't really reproduce and make copies of themselves. A neuron might have the exact same damage done to it that would cause another cell to become cancerous, but we'd never know the difference. Skin cancers, however, are much easier to spot, and the easiest cure is to remove the cancerous areas of skin. Other cancers, like glioblastomas, can be a death sentence depending on where they occur in the brain - sometimes they're in a location like the brain stem and can't be removed without killing the patient. Many cancers are treated with chemotherapy. Since a cancer is a specific type of cell, all you do is take poison that's more poisonous to that type of cell than others - hopefully you kill the cancerous cells and still have enough regular cells left to live. Fuck cancers. Fuck.", "There are heaps of cures. A few of my friends and family members have had cancer previously, they do not have cancer now. Why? Cured. The thing is these cures don't work on all patients, so we're still looking for all of the cures. The types of cures? Some types of chemo, radio therapy, early detection and surgery. It works really really well. URL_0 has a nice graph down the bottom highlighting how well all the current cures work.", "There's no money in cures. If you cure a disease or make a phone that doesn't crap out after a few years, your customers won't have to pay you anymore. Chris Rock once said, \"The government curing AIDS? That's like Cadillac making a car that last for fifty years... and you know they can do it! But they ain't gonna do something that fucking dumb! Shit! They got metal on the space shuttle that can go around the moon and withstand temperatures up to 20,000 degrees. You mean to tell me you don't think they can make an El Dorado where the fucking bumper don't fall off?\"", "Let's not forget that big companies see the money pouring in and skim most of the money off leaving a small portion going to actual cure research.", "It's a lot of reasons. People can have a lot of different kinds of cancer. Some for your skin, some for your blood, everywhere. Each of these cancers form slightly differently and affect your body differently. Cancer is difficult to study because most people don't realize they have it until they get really sick. Because of that, a lot of medicines are made for stopping cancer after it becomes dangerous and not before cancer forms at all. Stopping something that is already formed is much harder than stopping it from forming For cancer that has been studied a lot (such as breast cancer), medicine for cancer is harder to make. Very simply, cancer is just a normal cell that doesn't know when to stop growing. There are hundreds of different checks in cells to stop these uncontrolled growths. If one of them fails or a combination, it could be the cause of cancer. It's very hard to find. Some cancers are not well known at all and receive little money to study so you have even less knowledge on how to find a cure. Testing the medicine takes time., about 10 years of time. 4 stages of testing has to be done and if even one part fails, you start again from stage 1. This costs a lot of money and many companies don't really want to try because of how many medicines have already failed. Tldr; lots of parts make cancer something difficult to cure. There are different kinds of cancer, it's hard to study and not easy to make medicine for.", "Cancer is a mutation and not a single illness. As such we can treat types of cancers, but a one-size fits all treatment is very difficult.", "You can put all the money you want into it, but it the technology isn't there then it's just not there. Cancer is a genetic inevitability, not something like a common cold (which there is also no cure for, due to its genetic variation) Your cells mutate all the time, and your body is constantly killing off cancerous cells. The mutations aren't always the same, so when cells go cancerous and haywire, they can do a number of wild things. So a cure, in a sense, would be the ability to build something better then your body's immune system at detecting and killing these mutations. And if that were easy, we would all be living happy and healthy lives right now.", "Cancer is a copy error. Your cell divides, just like billions of cells in your body are doing all the time, but it gets the copy wrong. The next time that copied cell divides, it's even more wrong. Soon you've got a snowball effect spreading to other organs and systems. It can happen to anyone, at any time, though obviously some activities like smoking or radiation exposure increase the chances for copy error. If you live to be 200 and nothing else kills you, eventually you WILL get cancer, in the same way that even the most reliable car will eventually run out of oil. We can find activities that contribute to cancer and stop doing them. We can diagnose someone with cancer and kill all the cancerous cells with things like surgery and radiation... though often that stuff is every bit as bad for healthy tissue. But without some kind of miraculous breakthrough, on the order of solving the aging process itself, we can't \"cure\" it in the same way that we can cure an injury or an infection. Cancer is, in many ways, a byproduct of just being alive. That being said, don't feel like cancer research is a waste. More and more types of cancer become survivable for more and more people all the time thanks to all that money and effort. Fifty years ago, \"he's got cancer\" was practically a death sentence. Now it's something you have a very real chance of beating.", "The treatment of cancer is very profitable, so why cure it? People gotta die from something, so...if a global pharmacy corporation us making billions from cancer treatment...do the math, and follow the money.", "I'm probably going to sound like a conspiracy theorist, but whatever, I'll say it anyway. My step-dad was a scientist, he worked with other scientists. A few of them came up with a few things that would eradicate a normally common problem. The problem was that when you create a permanent solution for something, it'll essentially bankrupt companies that deal with those problems temporarily. Most of them and their ideas were bought out for a large sum. Now, I'm not saying that this applies to cancer research, and I'm sure we have very capable people working on a solution, but I wouldn't be surprised if it did. Anyway, I'm just trying to put out a different perspective on things, also I'm sorry I didn't explain it like you're five (first time here).", "I'm an MD PhD student studying immunotherapy for osteosarcoma. First off, plenty of cancers ARE cured every day. Many of them childhood cancers. Second, cancer cells have mechanisms by which they can evade the immune system. Third, many cancer cells look very similar to normal cells, so they can be very hard to target specifically without causing damage to normal tissues- often, organ toxicity is the limiting factor with chemo and radiation. Fourth, many cancer cells divide rapidly and erroneously allowing for new mutations to constantly occur and the ones that develop new drug reistant traits can therefore survive and stay one step ahead of targeted treatments. Fifth, many cancer cells can lie dormant and therefore be unaffected by the majority of cancer drugs targeting rapid proliferation, only to reactivate later down the road.", "So disappointed to read all the nonsense conspiracy theories! I am in Oncology drug development as a senior researcher and have been in this general field for about 15 years. As others have put it, Cancer is not a singular disease - between people and even within a patient. This is called cancer heterogeneity which is one of the biggest issues we face. Often our targeted therapies can kill one variant of the cancer cells, but leave behind a few cells that are resistant this is because the drug wasn\u2019t designed to kill those resistant cells. You will see now there are a lot of combination therapies that give multiple drugs to the patient in an effort to cast a wide net and kill as many variants of the cancer as possible. Even so, some patients are left with tumors that acquire mutations specifically to the treatment they have been given (and worked) - EGFR therapies are a great example of this. So now many of us are working on medicinal chemistry efforts to specifically target cancer cells that have these mutations. What many people don\u2019t think about it is what we call the Therapeutic Index. This is, how safely can we administer the treatment and still maintain a good response. Most cancer therapies have a very very narrow therapeutic index because of the nature of the drugs - selectively killing cells and avoiding killing your normal organ is very hard. We have a lot of drugs that kill cancer very well, but you know what happens if you take it - you die. They are too lethal and would obviously be deemed unsafe by the FDA. I just ask that people try to learn more about the disease from credible sources - Pubmed is your friend! Undermining the years and hard work from those of us who have decided to spent our lives on finding a good therapy is really disheartening (but not demotivating!). Anyway, I have one of my drug discovery efforts make it to a Phase 1 clinical cancer trial now so fingers crossed we can make it to our predicted human efficacious dose without hitting our predicted toxicities first!!", "Like the disease itself, it's terribly complicated. One factor is that cancer isn't a single disease, it's a group of diseases where some are similar to eachother and some are different, some are usually curable with the right treatment and some are almost universally a death sentence, variants may have different drugs they respond to and so on. Then, there's dealing with the actual problem at a physical level: killing cancer cells is easy. Killing cancer cells without killing off a *lot* of other cells you need is... not easy at all.", "Because a good portion of that money doesn't go to research. It goes to throwing parties for the rich so they donate more money.", "Lots of reasons Cancer has a lot of kinds: Each type of cancer (lung, liver cancer, etc.) can have several types, subtypes, further classification and so on. Each can have their own characteristics and only some drugs work on some others. Research, money, time, and drug development has to be spread out instead of a focused on one kind. Cancer is microscopic: Cancer is microscopic so we literally don't know if we got all the cancer. If we don't it will probably come back and possibly worse (it got more resistant to the drug, spreading to the body, etc.). If there was some way to go \"Oh here is every single cancer cell in the body\", cancer would probably be cured. Cancer treatment is crude: Cut it out, poison it, or irradiate the area. Sounds like war right? Well it's even worse because since everything is tiny, we have no choice but to do some collateral damage. Our tech just isn't good enough yet. Chemo is basically poisoning everybody in a village, but hoping it kills the people with faster metabolism first. Irradiation is basically bombing a suspected terrorist area. You'll never know if you got them all, or if you created more extremists through irradiation. Currently our best bets are target therapy or stimulating the immune system to attack it. Problem is, we're still not very good at either yet, either because we lack the tech or we lack the knowledge. Also targeted therapy will only work on a specific cancer since each cancer is different. And if the cancer mutates to something no longer targeted? Well good luck because our current tech isn't good enough to make a new target therapy drug that fast, let alone personalize target therapy.", "Cancer is an umbrella term for many different diseases that result in malignant cell production.", "Too much money is involved. A lot of the cancers we see can be attributed to the approved chemicals we consume and the environment we are in.", "Cancer has been cured for almost 10 years. It's not profitable. There's no money is curing people. Whereas there are billions upon billions to be made through chemo and radiation and medication", "Plenty of cancerS have been cured or become treatable There are literally hundreds if not thousands of varieties, breast cancer is not bone cancer is not prostate cancer is not leukemia is not skin cancer is not lung cancer There's no single cure for a spectrum of disease", "A lot of people have chimed in on various facets of the issue. I'll leave you with a simple word: variability. About a year ago, we were testing a drug for metastatic pancreatic patients. One patient, miraculously enough, was found to have no residual disease. She was shocked to hear the news. We laughed. She cried. We hugged. It was a great day. Other patients on this treatment...not so much the case. Same disease. Same drug. Different people. Its a shitshow most of the time.", "My wife works in a lab funded by cancer research grant money. Her specific study is on how cells migrate. Mutant cells vs normal cells. She's spent the last 3 years studying what look like hairs sticking out of the cells and how they affect movement, and now she's ready to publish her findings. It takes a long ass time to collect data on just one aspect of cell behavior. And these aren't even cancer cells. You have to generate enough data to study, then you have to find a pattern, and then you have to publish the data in order for it to be studied further.", "Part of the money is also going into improving existing methods to make them more effective or just making things easier on the patient, or a more assured diagnosis. My department is going to be trialling a more efficient form of Mohs processing so that people who require what we call \u2018slow Mohs\u2019, which will typically take 24 hours rather than the hourish turn around normal Mohs takes, will have that sped up, so they don\u2019t have to go home and come back in the next day or the day after. Better for the patient, gives them a higher chance of clearing in one day. I know that doesn\u2019t really answer your question, but I just wanted to add the money is going to other research aside from cures.", "Explaining cancer as if you were five: Every cell in your body has instructions. We call it DNA. Those instructions tell every cell to do three fundamental things: Eat, work and grow. Bad things can happen like sun burns or chemicals that hurt the cell\u2019s instructions. So let\u2019s pretend one of those functions is broken and doesn\u2019t work. If a cell can\u2019t eat, but tries to work and grow anyway, it will simply starve and die. If a cell can\u2019t grow but can eat and work, it will be fine for a while but all cells die of old age if they can\u2019t reproduce(grow). If a cell can\u2019t work but can eat and grow, it doesn\u2019t help your body. But it will keep eating and growing. It even grows faster because it doesn\u2019t waste time working. Those last kinds are cancer cells. They steal your bodies resources and don\u2019t perform a function. And since they look and act like your own cells(because they are), your body can\u2019t identify or stop them. This makes finding treatments very difficult."], "text_urls": [[], [], [], [], [], [], [], ["http://rebrn.com/re/i-always-hear-that-a-cure-for-cancer-is-misleading-because-cance-551955/"], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], []], "score": [4010, 636, 205, 81, 74, 25, 17, 9, 9, 8, 8, 7, 7, 7, 6, 6, 6, 6, 5, 4, 4, 3, 3, 3, 3, 3, 3, 3, 3]}}, {"q_id": "8jgkj1", "category": "Repost", "title": "What is a 401(k) and how does it work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dyzhqpp", "dyzi4ue", "dyzi5jc", "dz0lgfu"], "text": ["It's a type of tax-advantaged retirement account available in the US, set up by employers for their employees to use. The employee controls how much money gets put in, up to a certain amount ($18,500 for this year). The money is withdrawn straight from their paycheck to deposit in the account. The money is usually invested rather than just sitting in a savings account. In some companies, the company will match part or all of an employee's contributions to the account. You have to pay a penalty if you withdraw money from the account before you're 59.5 years old. There's two ways to put money in: either traditional (you don't pay income taxes on the money now, but you do pay taxes when you withdraw the money in retirement) or Roth (you pay income taxes now, you don't pay any income taxes on the money when you withdraw in retirement).", "As a society, we think it is a good thing for people to save and invest money for retirement. In fact, we think that it's such a good thing that the government tries to incentivize people to save. The government says \"if you agree to save money from your paycheck now - and not touch it until you retire - we'll give you tax discounts on that money.\" The specific part of the tax code which allows this is defined in section 401 subsection k.", "It's a form of tax advantaged retirement fund that an employer can contribute to. Let's break that down. Tax advantaged: You don't pay taxes on income earned from assets in the fund. Suppose you buy a government bond. Normally, when that bond pays out, you have to pay income tax on your profit. But if the bond is in a 401(k), you don't. Similarly, you wouldn't have to pay tax on stock dividends, or capital gains. The idea here is to encourage people to set aside money for their retirement, and most of your assets in a 401(k) will be in the form of investments that would otherwise have tax implications, rather than just being in cash. The \"catch\" is that you have to pay income tax when you take money out of it after you're retired. However, because most people earn less money when they're retired than when they're working, they'll be in a lower tax bracket, so the income tax their paying will still likely be less than what they would have payed without the 401(k) Retirement fund: Money you've saved away for retirement. You can take money out of a 401(k) before you retire, but there's a big tax penalty. So don't put money away that you aren't OK doing without until you're over 65. Employer contributions: Employers are allowed to contribute funds to the 401(k)s of their employees. This is general done by matching contributions up to a limit - that is, if you say \"I'm going to set aside $100 from each paycheck for my 401(k)\", an employer would make that contribution for you come payday, deducting it from your pay from that period, but then would *also* throw in $100 additional. So it's a nice perk for attracting and holding on to good talent.", "You'all suck at ELI5. What kind of fucking five-year-old knows what a \"tax-advantaged retirement account\" is? Lets give this a go. -------------------------- Lets pretend that you help your friend Tom with his parents' lemonade stand and they gives you a cut of the money they make. However, for every dollar that you make at the stand, your big brother (David, not Rick) takes 40 cents from you, you know, because David is a dick. A 401k is like having your own piggy bank that Tom's parents can pay your money to you directly (instead of paying in cash). The beauty of this is that David can't touch a penny of it until you crack open the piggy bank. Additionally, you have awesome parents who want to teach you to be good with your money, so for every dollar you have saved at the end of each week, they will give you a penny. Now, while you can't crack open your piggy bank for a long time (until it's full), you're getting a ton of penny's from your parents because your dick brother David isn't stealing like half of your money first. And, while David is still going to take his cut when you crack open your piggy bank, you end up with WAY more extra pennies in the end. There's also Employer Match. Tom's parents are in cahoots with your parents and they like the idea of you not blowing all of your money on candy/toys, so for every dollar you put into the piggy bank, Tom's parents add a second dollar to the piggy bank."], "text_urls": [[], [], [], []], "score": [118, 39, 5, 3]}}, {"q_id": "8jltxy", "category": "Repost", "title": "Why, after a poor night of sleep and subsequent all-day fatigue, do I get a \u201csecond wind\u201d of energy that night with no interest in going to bed?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dz0pbbt", "dz1n55r"], "text": ["It's the adrenaline and other stress hormones! First, your body is all, \"Ugh, I'm tired. I wanna go to sleep. I'm so sleepy.\" But you say, \"Too bad, body, we're not going to sleep now.\" Then, eventually, your body is like, \"Dang, we're staying up all day/night, there must be a good reason for it! Like some kind of threat! We better be super alert!\" Your body doesn't realize you're just playing video games or whatever you do if you pull an all-nighter (for example), it just knows you're awake when you shouldn't be and thinks there must be something important (i.e. dangerous) that requires being awake. So it responds by releasing adrenaline.", "Holy shit I know why this is a thing! Okay so the jist of It is that man evolved a chemical mechanism by which more dopamine(a neurotransmitter that stimulates your reward centers and can boost wakefulness) is released into your brain. Basically your brain is trying to shift up to 11 because it thinks you're stalking a wooly mammoth or running from a saber tooth tiger, when really you're just grinding out those 99's on runescape. The reason why you can't repeat it is because all that dopamine can disrupt normal brain function over a prolonged period of time, leading to that dopey heavy sleepy feeling. It also fucks up your metabolism, which can lead to weight gain. Fun fact, this is pretty similar, albeit less intense, to what happens when you take certain drugs. A dopamine rush followed by a plateu and coming down from the high. If you get great sleep for a long period, then miss a night, you'll feel it again, trust me guv."], "text_urls": [[], []], "score": [106, 3]}}, {"q_id": "8jvx58", "category": "Repost", "title": "Why do the vast majority of political cartoonists all use extremely similar (almost identical) drawing styles?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dz2xmqw", "dz2u026", "dz3hza4", "dz35h7w"], "text": ["A lot of them are emulating Thomas Nast who is history's most influential political cartoonist. Nast was the first person to depict Republicans as Elephants and Democrats as Donkeys. His influence is akin to Jack Kirby's kinetic comic book drawing style that revolutionized super hero comics.", "There's a lot of variation when you compare them side-by-side. That said, they're all caricatures. To sell a desired message, you exaggerate certain features to emphasize whatever it is you're trying to emphasize. It let's you say a lot with just one or two images.", "I found a big difference when moving to the UK from France (which had a closer style to USA). The UK draws characters in a much more gruesome way, pointy features, baggy eyes, sickly skin colour, and much more attacks on personal clothing, physique, and symbols. (Communist Corbyn, Theresa may with leopard shoes and a belly...). Where France and the USA made them look much more friendly and would make a caricature of the ideas instead: By exaggerating their position, or words they say rather than attacking the person themselves.", "A lot of them are not very good to be honest. I would say the majority are satirists first and cartoonists second. I think the style of the cartoon suits the media though, all inky and scratchy and serious looking. Almost as if they are so angry they can't hold the pen properly. Graffiti but serious and grown up. Most likely it has a history of court sketches, and how images were printed onto metal sheets and pressed onto the newspaper. You will find there is a style common in most shared media, for example architectural illustrations have the same shakey ink scribbles too."], "text_urls": [[], [], [], []], "score": [340, 43, 26, 19]}}, {"q_id": "8jxhvj", "category": "Repost", "title": "Cardio gets the heart working which ultimately makes it stronger. So why do recreational drugs that do the same thing cause harm to the heart?", "title_urls": {"url": []}, "selftext": "Shouldn't cocaine, for example, help improve the cardiovascular system?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dz3cl9i", "dz3bmy9", "dz39bwz", "dz3estd", "dz37n5e", "dz4bk26", "dz3nbfu", "dz3g44n"], "text": ["when you exercise your whole cardio vascular (heart,lungs and arteries and veins) system adjusts to get more oxygen into your muscles, and also more waste out. All the components are working in tandem, increasing, decreasing and stabilising as required. Its a very nicely synced system when you take cocaine its JUST your heart that increases. its now out of sync with rest of the system, even pushing against it and making your heart strain. That's the problem. I suppose the cocaine case is a bit like having one formula-1 wheel on a car: its out of sync with the rest and you're gonna have a bad time.", "Higher heart rate alone is dangerous for the heart. Higher heart rate with higher oxygen levels in the blood (due to exercise) is what\u2019s preferred to obtain a healthy training of the heart :)", "I used to think the same thing about panic attacks. \"I have heart palpitations! My heart is getting a great workout!\" But the stress hormones associated with panic attacks isn't good for the rest of the body. And the damage to endothelial cells of blood vessels from high blood pressure isn't good either.", "When you do coke your blood vessels shrink up and the heart beats faster to push against it. Fighting against pressure. Thickens walls of heart, reduces pumping capacity. With exercise its more about flow, and you have more blood coming back to the heart. Increases stroke volume which lowers heart rate when resting. This is why endurance athletes have low as fuck heart rates.", "Exercise stimulates the heart to increase in a regular and proportionate amount, some drugs can cause an erratic and very rapid heartbeat.", "Increased heart rate is a side effect of cardio, it is not the goal of cardio. The goal of cardio is to increase your heart's efficiency at delivering oxygen to the body. Simply increasing your heart rate does not increase it's efficiency, it increases its workload, which is not desirable over extended periods of time.", "Cardio gets your entire cardio vascular system working, not just your heart. When doing cardio, veins and arteries expand to receive more blood because your entire body is demanding it. A stimulant that increases your heart rate only does not do this, so your heart is pumping like mad through veins and arteries that are not expanded and calling for it putting a lot of strain on them. EDIT: Added a word.", "Nope. If you have any condition that makes your heart work harder for a long time , you'll trigger some cellular pathways on your cardiomyocyte (muscular heart cells) that will make them grow from the \"inside\" of the heart and eat up the space reserved for blood in the ventricules. Your heart will be able to send less blood to the heart and wil try to adapt by beating faster and stronger and so on till cardiac failure. If you have your heart work harder for a while buy doing EXERCISE (or anything that'll stimulate exercise), it's different. During exercice, you'll produce growth hormones, growth hormones will inhibits the pathways making your heart get bigger from the inside and will instead favorise the cellular pathway making your heart \"expand\" : Your heart will get a bit bigger, ventricular cavity will get a bit larger and you'll be bale to send more blood with less heart beat : That is why athletes have low heart rate."], "text_urls": [[], [], [], [], [], [], [], []], "score": [628, 234, 39, 34, 10, 3, 3, 3]}}, {"q_id": "8jy17j", "category": "Repost", "title": "Yanny Laurel debate", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dz3c7lj"], "text": ["This is an audio troll. They masked a high pitched \"yanny\" over a low-pitched \"laurel\" and which you hear depends on the output bias of your listening device (ie: if your device tends to be tinny and have little/no bass, you'll hear \"yanny\" and if you have a bass-heavy EQ mix, you'll hear \"laurel\")"], "text_urls": [[]], "score": [4]}}, {"q_id": "8jyam3", "category": "Repost", "title": "Why does 60 degree air feel decently warm, but 60 degree water feels super cold?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dz3eqbm", "dz3escr"], "text": ["The secret lies in a property called conductivity. Air conducts heat very badly. So cool air cannot transport your body heat away very quickly, your heat stays with you, you do not feel cold. Water is way better at conducting heat, so it quickly takes your heat away, sometimes quicker than your body can produce it. So you feel cold. That also is why you experience hypotermia much quicker in water.", "When you feel cold, what you're feeling is heat being transferred out of your body. Some things can do this better than others. Example: Sit (naked) on a metal bench vs. a wooden bench in the same place. The metal bench will feel colder, even though the material is the same temperature, because it's a good conductor of heat. Water conducts heat more effectively than air."], "text_urls": [[], []], "score": [5, 3]}}, {"q_id": "8ldbwi", "category": "Repost", "title": "; If the court orders your to pay a ludicrous sum ($37m) that you blatantly cant afford... how do you pay it?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dzenosg", "dzenoi2", "dzf2iya", "dzffceu", "dzfjlok", "dzewuuv", "dzevaq4", "dzfgj71", "dzf68ol", "dzengru", "dzfmusf", "dzfy0bh", "dzfop0x", "dzfiiiq", "dzfn6kj", "dzfm1f4", "dzfprbz", "dzff8rr", "dzfn4xl", "dzfjuwq", "dzful3i", "dzfx4zp", "dzftttq", "dzfuglk"], "text": ["Typically the court establishes a payment plan based on your income and expenses that requires you to pay much of your disposable income towards the judgment but leaves you enough money to live at a reasonable standard of living. Also, in this case: > [And after 10 years, if the boy successfully completes probation, doesn't commit additional offense and complies with the payment plans, the court can grant full or partial satisfaction of the restitution judgment.]( URL_0 )", "In the US, depending on the order they can take property (normally not your house or primary car), take savings, garnish wages, and take any other liquid assets you may have. The garnishing of your wages can last for years if not the rest of your life.", "First of all, if there's a judgment against you in the US, the court doesn't care if you can pay it. You either pay, or you don't pay. Depending on why there's a judgment, you might be able to declare bankruptcy and get rid of it. Secondly, if you really can't pay, then you can still negotiate with the plaintiff. \"You know I can't pay you $37m. But, how about this: I pay you $10 a week for the next 20 years. If you don't accept that, then you're going to have to execute on the judgment, which will cost you time and money. And, if you try that, then I'm just going to declare bankruptcy.\" Third, the plaintiff can execute the judgment. He/she can order the bank to give him the money in your account, get the sheriff out to your house to grab your TV and your car, garnish your wages, etc.... (The exact remedies depend on what state you're in and how you got the money. Garnishment, for example, is typically limited to a percentage of your income. Social Security benefits are immune, etc....)", "If you owe thousands, you\u2019ve got a problem. If you owe millions, they\u2019ve got a bigger problem.", "Is this in reference to the Idaho teen sentenced to pay $37.5 million in retribution for a forest fire?", "I assume you are talking about the gorge fire kid? The court did not order him to pay $37M. The actual outcome is that he\u2019s going to pay a garnishment that is set based on his income for a maximum of ten years. If he can make it ten years without legal trouble the rest of the amount will be waived. If he gets in trouble his paychecks will continue to be garnished up to a maximum of $37M.", "They can do a wage garnishment up to 25% of their disposable income. So they calculate poverty and then garnish 25% of every dollar after that. So realistically, if he were making $40k a year, he'd be garnished like $6k-$8k.", "At some level, it's just the point of it all. No one expects payment on the $37m. Not the judge, not the prosecutor, not the bailiff, not the court clerk, not the insurance companies, nobody in the city, and nobody reading this on reddit right now. Nobody. It's just to let people know. It's like the entire USA is shaking their head at the person, \"How can you be so fucked up, there's nothing we can to do the level of your fuck up.\"", "you... don't. there's a reason \"judgment proof\" is a phrase. you can't squeeze blood out of rocks. but that judgment is going to hang over your head for at least a very long time so say goodbye to any ability to accumulate wealth.", "You become bankrupt, the crown takes all your possessions, wealth, and any future income to pay the fine. You're going to live a life of poverty, living on what the government deems livable. If you get a job and make money, you'll only see a small part of it.", "My brother is an excellent civil personal injury attorney. He often has potential clients come to him with tragic stories where the person who committed the tragedy doesn't have any assets or meaningful insurance. For example, a 23 year old man was texting and driving and ran a red light into my brother's potential client, who ended up losing a knee and a hip as a result. The 23 year old only had basic collision insurance and no real assets. My brother had the terribly unfortunate duty of letting him know that it would be very expensive to sue that man and that it was almost certain that he would never see any of the money from a judgement. My brother often says that having 0 assets is an excellent defense to a personal injury lawsuit.", "My former boss (restaurant owner) always foolishly waited until the last minute to pay his local taxes which he paid in cash. (Again very foolish) The lady who took his money gave him some sort of fake receipt or made it so the other side of the hand written carbon copy was blocked and then filled in a smaller amount later. Anyways she stole over $14,000 in tax money paid from him. So naturally he gets audited years later and by the grace of God he has this receipt. If he didn\u2019t have this receipt he would have been RUINED. Tax evasion all that crap. Well she finally got caught and you know what her sentence was??? Restitution of 1 dollar a month, 3 years probation and an apology letter... they calculated that it would take 1,235 years before it was paid back...", "If you owe someone $10,000, you have a problem. If you owe someone$1m, they have a problem.", "Should probably add a little more detail, like the person being a mid-teen, but thanks for asking ive been wondering this too, I was thinking maybe some special federal insurance grant type deal, where those agencies can \"write it off\" and get an insurance payout.", "Now, 37m is absurdly high, thus I would assume it's related with some sort of damage claim (like, blowing up a gas station on accident or something). In Germany, you are legally mandated to have a \"Haftpflichtversicherung\" (~Foreign Damage Insurance). It kicks in whenever you, without malicious intent or severe neglegience, end up being sued for damages of any kind. Even the most basic of those insurances cover up to 20m easily, and cost like 5 bucks a month (if you don't get sued, afterwards they might uprank your payment plan). Otherwise you'll likely be forced to declare bankruptcy, which forces you to make all your finances visible to the court, paying as much money as fair and possible (i.e. if you own 2 cars, you will definitely be forced to sell 1, but you can keep the other if it's evident that it's required for your job). You will then have to remain in that state a number of years (5 or 7), not allowed to save any money past a minimum. After that time period, all other debts are legally nulled.", "Are you the kid who started the salmon creek fire and is now ordered to pay 36 million dollars?", "Wow. Pretty much **zero** of these answers are even close to accurate. I can speak for the process at the federal level. The answer is that once the court issues a judgment, it goes to [Asset Forfeiture (a very dirty word on reddit).]( URL_0 ) Asset Forfeiture will enforce on any forfeiture money judgments and record liens wherever you may have property and will continue to do so for the next twenty years (not \u201cthe rest of your life\u201d like most commenters are claiming\u2014statute of limitations at state levels exist for varying lengths). Forfeiture money judgments basically seize any assets you might have to pay toward that restitution. In spite of the tinfoil hat levels of conspiracy on reddit that surface anytime asset forfeiture makes the national news, we don\u2019t take your house. [Believe it or not, we actually do some good from time to time.]( URL_1 ) Once Asset Forfeiture has done all they can, the case is filtered down to Financial Litigation. Financial Litigation will file a lien wherever we think you have property, probably send you a demand letter for payment (yes, even if we know you can\u2019t pay\u2014we have to show we put you on notice), and we\u2019ll send you a sworn financial affidavit (or to your probation officer) to fill out for your file in our office. That\u2019s more or less a very simplistic explanation of the process. We periodically review your file, send you a new financial affidavit to fill out, run your credit, and send out the occasional bank subpoena to make sure you\u2019re not lying on your financial affidavit and after 20 years from the judgment date (or when you get out of jail) the debt just goes away.", "How was it starting a huge forest fire?", "Did you see that ludicrous display last night?", "Wasn't this the forest fire sentence? Some 15 year old kid..", "You quit working and live off welfare. Your life is ruined either way. If it happened to me I'd move to Guatemala or something.", "You pay what you can afford every month. It might just be ten bucks a month, forever. Or don't pay because they can't squeeze blood from a stone, but there will likely be consequences.", "There\u2019s a huge loophole. If you rent your house, lease your car, and get a tip based job such as waiter or bartender you can get away with never paying. Source: I personally know someone who owes $1m for getting caught up with fraudulent mortgages back before the recession and he still lives an amazing life.", "In Texas the debtor often simply doesn't pay any amount. There's a saying in the law, \"you can't get blood from a turnip.\" Most judgement debtors are turnips. People that commit horrible torts often don't get sued because the suit is costly and the judgment is just a piece of paper so the firm and the plaintiff would end up wasting money establishing liability. There's not supposed to be debtors prison in this country so there's few legitimate consequences for not paying a judgment especially if the debtor is the kind of person who deals in cash and doesn't own real estate. This is one of the most commonly misunderstood aspects of the law."], "text_urls": [["https://www.npr.org/sections/thetwo-way/2018/05/22/613374984/judge-orders-boy-who-started-oregon-wildfire-to-pay-36-million-in-restitution"], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], ["https://www.justice.gov/afp", "https://www.justice.gov/archive/usao/nys/pressreleases/June09/madoffforfeiturepr.pdf"], [], [], [], [], [], [], []], "score": [2659, 506, 289, 168, 163, 113, 26, 25, 21, 13, 9, 7, 6, 6, 6, 5, 5, 4, 4, 3, 3, 3, 3, 3]}}, {"q_id": "8lzwtn", "category": "Repost", "title": "What happens to air trapped in space?", "title_urls": {"url": []}, "selftext": "Let's say a spaceship has a breach and the ensuing vacuum sucks out all of the air, what happens to it once it's out in space? Where does it go?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dzjq3su", "dzjq4x6"], "text": ["> Where does it go? Everywhere. It expands in all directions becoming less dense with great rapidity. Each individual gas particle will continue on its way until it hits something. Generally speaking this will probably occur from the gravitational influence of some large body such as a planet or star if it happens at all. Where exactly it ends up really depends on where the spaceship is when it is breached. If in orbit around Earth then the gas will end up falling back to Earth eventually as the gas particles eventually drag against the outer edges of our atmosphere. If in interstellar space then the gas is probably there for an extremely long time.", "Air that was trapped is now free to move wherever. Matter will fill in empty space. ELI5: when you fart the smell spreads throughout the room until it gets so spread out it doesn\u2019t smell anymore. Air in space will do the same thing except the room is as big as the universe. So don\u2019t worry about farts, they too will pass."], "text_urls": [[], []], "score": [6, 3]}}, {"q_id": "8n2g1s", "category": "Repost", "title": "How do we know that a number is irrational? For example Pi = 3,1415.... and it lasts forever, how do we know that it's forever?", "title_urls": {"url": []}, "selftext": "Sorry for my bad English.", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dzs9zox", "dzsf5p4"], "text": ["\"Lasts forever\" is just one property of irrational numbers, it's not what makes them irrational. A number is rational if it's the quotient of two integers, so we prove they are irrational by showing that they can't be the result of dividing one integer with another. [Proof that pi is irrational]( URL_0 ) is unfortunately way too complex for ELI5, but there's [a simple proof that the square root of 2 is irrational]( URL_1 ).", "We know because pi is an irrational number. More to the point, we know it is not a rational number. (warning, math ahead) A rational number is one that can be represented as a ratio of two integers. For any repeating or terminating decimal out there, you can do a little math to express it as a ratio. With a terminating decimal, it is pretty easy: 0.123 = 123/1000 Repeating decimals require a little algebra: n = 0.123123... 1000n = 123.123123... 1000n - n = 999n = 123 n = 123/999 = 41/333 What does this have to do with pi? It means that either a) pi can be expressed as a ratio of two integers, or b) pi cannot be represented as a terminating or repeating decimal. If we can show there is no way to express pi as a ratio, the only remaining possibility is a nonrepeating decimal. In 1761, this is exactly what Johann Heinrich Lambert did. Unfortunately, his proof, and others like it, require advanced math we'd rather not get into. Lucky for us, the proof that \u221a2 is irrational is pretty straightforward: assume a and b exist, such that a/b = \u221a2, and a and b have no common factors a^2 / b^2 = 2 a^2 = 2 * b^2 therefore a is even, and there exist a k such that a = 2k (2 * k)^2 = 2 * b^2 4 * k^2 = 2 * b^2 2 * k^2 = b^2 therefor b is also even However, we assumed a and b had no common factors, so they cannot both be even. This contradicts our original assumption, which proves it must be false. There are no such numbers a and b, which means \u221a2 cannot be represented as a repeating decimal, and must be irrational."], "text_urls": [["https://en.wikipedia.org/wiki/Proof_that_%CF%80_is_irrational", "https://en.wikipedia.org/wiki/Square_root_of_2#Proof_by_infinite_descent"], []], "score": [26, 9]}}, {"q_id": "8nfnvb", "category": "Repost", "title": "How do honeycombs and beeswax form nearly perfect hexagons?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dzv6dsd", "dzvcm34"], "text": ["The hexagon is a very spatially efficient shape which uses less material. Try this experiment: wash your hands with soap, and spread the lather out on a flat surface. The bubbles will spontaneously acquire hexagon-like shapes and arrange themselves neatly. You see the same patterns in basalt columns and mudcracks because it fills the space using little energy.", "Actually, they sort of don't. The bees actually make circles, but as they build the hive the pressure of the circles on each other presses the sides flat against one another. If you get a circle and surround it with other circles, then press them inward, they will flatten the edges where they contact. This happens to the whole hive wall as it is built and produces hexagons, which are fortunately an incredibly strong shape so the bees kept making the hive the same way."], "text_urls": [[], []], "score": [9, 3]}}, {"q_id": "8nnmxa", "category": "Repost", "title": "Why phones can have 8 cores and sometimes more but even most high end computers half only 4 cores.", "title_urls": {"url": []}, "selftext": "It would make sense that phones would need less seeing a computer, which needs more processing power can have fewer, and there can't be that much of a difference in (potential) processing power, surely?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dzwxd6w", "dzwv4pd", "dzwwr8u", "dzx57w0"], "text": ["Even sub $200 processors like the i5-8400 now have 6 cores while AMD offers desktop chips with 16 cores/32 threads (on the server side you have Intel offering 28 cores with 56 threads) so part of the answer is that you simply don't know what is in desktop computers these days. Then there is the fact that while phone processors might advertise 8 cores that doesn't mean 8 *equal* cores. A big reason for having multiple cores on phone processors is not for speed but for energy efficiency. Only the core(s) needed for a specific task are powered on while the others are asleep. This leads to specialization with only a few cores being strong general purpose ones like you might expect. Finally there is the issue of what is practical. More cores means more heat and more cost to build. On the desktop there are usually limits on how much of that power can actually be used - most games for example show very little improvement beyond 4 cores (in fact 2 cores with 4 threads is actually the sweet spot right now before you start seeing large performance losses). While more cores are useful for some productivity tasks (like encoding video) many desktop users aren't taking advantage of that so a chips single thread performance has a much bigger impact on how 'fast' their computer is. This is reflected in processors like Intel's budget i3 line which boasts some extremely respectable single threaded performance but tops out at 4 cores, giving it the maximum bang for the buck for most average users.", "More cores does not mean more processing power. It means more simultaneous processes. Phones and other mobile electronics are often used to do several tasks at once (play music, navigate, web browse, run background apps, etc) while home computers generally are not. A home PC is more often used to run one or a few very processing intensive tasks (like gaming). So it benefits more from having a smaller number of more powerful cores.", "All cores are not created equal. The cores in phones are generally ARM-based cores, which are optimized for small size, low cost, low power consumption, and OK processing power. In a PC, they are x86-based cores, generally optimized for processing power. In addition to the correct answers given by /u/rhomboidus and /u/ameoba , I'll point out that most PC cores are dual-threading, which (kind of) means that they act like two cores in one. So a PC with 4 cores can handle as many processes as an 8 core ARM device, but the x86 cores will do their jobs more quickly.", "The arm processors uses the Big.Little model. So they pair a low end core with a high end core. Each pair shares an immediate local memory. They don't run at the same time. You get either the low end core or the high end core. So effectively only 4 cores at a time. The advertising still counts each core as independent, i.e. 8 cores. The Big little model, lets the phone use the low end cores to focus on power saving, but switch to the High end cores when high end processing is need i.e. games. The way the low end cores save power is by using a lower voltage, which means less power is consumed, but lowering the voltage slows down the speed of the cpu. The High end cores increase voltage which increases the speed of the cpu but uses more power. The PC processors accomplish the same thing by using the same core, but dynamically raising and lowering the voltage of the cpu. So when you need the horse power, they raise voltage, which increases the speed of the cpu and the power consumption. When the PC processor needs to save power, it dynamically lowers the voltage, which reduces the speed and reduces the power consumption."], "text_urls": [[], [], [], []], "score": [7, 4, 4, 3]}}, {"q_id": "8nt5qn", "category": "Repost", "title": "How do huge stores enforce a customer ban?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["dzy3nx9", "dzy5i7g"], "text": ["I used to work in retail and the answer is poorly. We can't possibly track any given customer across hundreds or thousands of potential stores. The ban really has two purposes: - It is a deterrent - many customers are too afraid of consequences to show up at the store again. - _If_ we do recognize them, we have justification to call the police and have them arrested for trespassing, because they have gotten formal warning not to set food on the property.", "Through the threat of criminal prosecution. There is no effective way a store like Walmart can prevent a banned person from returning to one of their stores. However, getting kicked out of a store means you got *caught* doing something to get you kicked out of a store. If you get caught again, you are looking at a criminal trespass charge. If you don't get caught, you probably aren't causing trouble anymore, which is pretty much all the store wants."], "text_urls": [[], []], "score": [15, 7]}}, {"q_id": "8o7lre", "category": "Repost", "title": "What is actually happening when people \"see stars\"?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["e01b1d8", "e01c3kq"], "text": ["One instance of seeing stars is when you close your eyes and see what looks like \"TV static\", that black and white snow storm of noise. Your eyes take in an incredible amount of information. Shapes, colour, movement. What am i seeing, is that fur, is that a dog, i love dogs, how far is it, its coming closer, looks like a Labrador. All that information is then processed by your brain in a heartbeat. When you close your eyes, your brain doesnt have to process any of this. The neurons in your brain are used to firing almost non stop. It fills in the blank with a sort of visual static, or stars.", "There are a number of tiny extraneous objects in you eyeball, mostly dead cell fragments. A blow or even things like a fall, handstand or rapid shake of the head can stir more up from where they've settled to float around in your field of view. Because they're tiny and not in focus, you get surrounding bright and dark rings as light coming into the eye diffracts round them. Because of this they show up more than they otherwise would based on their size."], "text_urls": [[], []], "score": [5, 3]}}, {"q_id": "8ozyln", "category": "Repost", "title": "When glancing at a clock, why does the first second after glancing at it sometimes feel longer than the rest?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["e07btq8", "e07c0fy", "e07ljb5", "e07msbp", "e080ojl", "e08o9c1", "e07qu4r", "e07mgme", "e07tvn0"], "text": ["An interesting phenomena, it is because the brain doesn't store what you saw during the time your eye spent moving, instead the brain fills in this time with what you saw when you stopped moving your eye. Wikipedia has an article on [chronostasis and the stopped clock illusion] ( URL_0 ) if you want to read about it.", "When you move your eye or blink the images from your eyes are just blurry or dark and therefore quite useless for your brain to interpret. So the brain use the information from the view before and after the eye movement to fill in the blanks. So if you move your eye to the clock as the second hand is moving your brain does not see the second hand moving and interprets it as if it have been standing still during the entire time you moved your eye. So the first second looks longer because your brain makes the wrong assumption.", "I will try to explain this step by step. First, you are looking at something that *isnt* the clock. Your brain is focusing on making that image make sense and be clear, with detail, color, etc. Then, you move your eyes to the clock. It takes a few milliseconds for your eyes to actually move there, and once they land on the clock, your brain has to \"stabilize\" the image, which takes a few milliseconds as well. Because of those few fractions of a second it took for you to move your eyes and find the details of the new object you're looking at, your brain just decides to fill that space with the new thing you're looking at, instead of making everything blurry and unclear. So, when you look at a clock, your brain is filling your vision with the image of what you moved your eyes to, instead of the blurry eye-motion that it would've been. That image is whatever time was on the clock when you looked at it. This makes that first second look/feel longer. It **is** longer. Your brain is literally telling you that it is longer.", "Basically, it has to do with a phenomenon called \"saccadic masking\" where the brain selectively blocks visual processing during eye movements so that neither the motion of the eye (and subsequent motion blur of the image) nor the gap in visual perception is noticeable. You can \"observe\" this phenomenon yourself by looking at your eyes in the mirror; look back and forth from eye to eye and you'll notice that you cannot see your eyes move, even though you know they're moving and an observer would be able to clearly see your eyes moving. The process works like this: in the beginning milliseconds of your eyes moving, a signal is sent to your brain to start this process of masking and your brain starts receiving significantly reduced information from your eyes. When your eyes move to the clock, your brain also receives the message, \"hey, a little bit of time just passed there and we didn't send you any information\" so what the brain does in response is actually backwardsly fill in the period of time that you \"missed\" with what your eyes refocus on. So, when you refocus on the clock, your brain receives basically \"extra\" visual information of the clock with the second-hand at whatever time it's at which can make a second seem extra-long.", "Your eyes fill in the blank time that it ignores while your eye moves. The reason it ignores that time is because otherwise our eyes would blur like a video shot by a shaky handed camera man. To avoid the blur your brain has 3 choices. Completely blind you while your eyes move, continue to show you what you were looking at prior to moving, or extend the time you see the thing your eyes moved to look at. And of the 3 your brain chooses the last one because being blind is a disadvantage in nature, and if you look toward something its best to have as much time as possible to process whats going on before its to late. If im picking berries and a wild animal comes to attack me its better to see them quicker and longer then the berries.", "Your brain blurs out what you see in the time between looking down and looking at the clock, so instead of your \u201cframes\u201d going 1-2-3-4, with 4 being the clock, it replaces that 2-3, with 4, making you \u201csee\u201d 1-4-4-4, and appear longer. Vsauce has a video on this :) URL_0 Edit: link to video", "Because each time you do a saccade (a rapid movement of the eye), you are technically blind. Your brain retroactively fills your memory with the first thing it sees after the saccade, so that\u2019s longer. Your brain is weird \ud83d\ude48", "When you looked at a clock for the first time, there will be \u201cframes\u201d missing for a very short amount of time, instead of making those missing frames black, your brain fills the missing frame by making the second \u201clonger\u201d than it should be", "On top of what everyone is saying about the eye movement, the brain also pays more attention when it sees something novel, and relaxes back to the laid-back glide when things go as expected. You can see this with short videos: the first watch-through seems slower and appears to take more time than the following repetitions."], "text_urls": [["https://en.m.wikipedia.org/wiki/Chronostasis"], [], [], [], [], ["https://youtu.be/nNBTLbw1_2Q"], [], [], []], "score": [8130, 619, 282, 52, 12, 9, 8, 5, 4]}}, {"q_id": "8pusfc", "category": "Repost", "title": "In real life we can create a green paint from the combination of blue and yellow paints. Then why is it different in the electronic world where green is considered the primary colour, and yellow is the combination of blue and green?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["e0e6suj", "e0ec5mx", "e0e7c6l", "e0e9932", "e0eo675", "e0ef6n7"], "text": ["You are comparing pigmentation with light. They are different. Pigments filter light out (absorb it instead of bouncing it off). When you mix all primary pigments, you get black because they are filtering out all colors of light. When you mix light, you are adding lights to each other. When you mix all the primary light colors, you get white.", "ELI5: Let's say you want to create a sculpture. Mixing paint is like starting out with a big chunk of rock, and having to remove some rock to reveal a figure inside of it. Mixing light is like starting out with an empty table, and having to add clay to get the figure you want. Paint is like removing chunks of rock, while colored light is like adding chunks of clay. To our eyes, both seem like just simple colors, but in reality the two work in opposite ways: one removes color, the other adds color. ----- There are two mistakes in your assumption. In paint, you mix Cyan (not Blue) and Yellow to get Green. When mixing light, you combine Red (not Blue) and Green to get Yellow. [These are the rules]( URL_0 ): * White = Red + Green + Blue * Red + Green = Yellow * Red + Blue = Magenta * Blue + Green = Cyan * opposite of Red = Cyan * opposite of Green = Magenta * opposite of Blue = Yellow When we say we're \"mixing paints\", we *start out* with white paper so we already have all the colors there before we even do anything. Therefore, you must *remove* colors to get other colors. Paints act like filters as they remove colors. When you mix Yellow and Cyan, you are not actually mixing two colors, but you're really *removing* two colors. Yellow paint removes Blue, Cyan paint removes Red, which leaves you with the only color left: Green. Remember, White = Red + Green + Blue, therefore White - Blue - Red = Green. When we say we're \"mixing light\", we *start out with darkness*. This means you have to *add colors together* to get anything. So you simply add whatever colors you want. You get Yellow when you mix Red and Green light, Magenta when you mix Red and Blue, and Cyan when you mix Blue and Green. And of course White when you mix Red, Green and Blue. Computer screens mix light because when you turn them off, they're black. So they start out black and therefore can't remove color because there is nothing to remove. Printer ink and paint must remove color because they start out with white paper and already contain all colors, so they must remove some colors to \"gain\" other colors. There aren't really two models for mixing colors. The confusion comes from the expression \"mixing colors\" that is equally used for both light and paint. When mixing paint, we're not mixing colors, we're actually subtracting colors, because paint acts like a filter.", "it\u2019s called additiv and subtractive colors.. if you mix all physical colors you get some kind of black. If you mix all colors from light it\u2019s white", "In addition to the difference between light absorbing pigments and frequencies of emitted light, there's the fact that your eyes have red, green and blue sensors in them that absorb those frequencies of light. Yellow is figured out by your brain based on the amount of light being absorbed by those sensors. So in the electronic world, light emitters attempt to fool the sensors in your eye, as opposed to pigments, which just absorb whatever frequencies they absorb and reflect the rest back to your eye.", "Okay so let's talk about paint and how it makes colors. First of all, you've been taught colors wrong in art class. The primary colors for paint (aka the primary subtractive colors) are Cyan, Yellow, and Magenta. Not Blue, Yellow and Red. BYR is just a more normal and \"natural\" set of colors for artists to use. (Fun fact, many printers use CMYK (the K is for black) because it can produce all the same colors as BYRK, and more) Our eyes can only see Red, Green, and Blue light. (Sidenote: it can see yellow light, but that's because yellow light is interpreted as a bit of green and a bit of red) White light is essentially all colors of light mixed together, although since our eyes can only see Red, Green, and Blue, white is _really_ just a mix of those three colors. Why aren't those the primary colors for paint though? Paint works by absorbing light, and then reflecting other light. Let's let CMY be the primary colors and then see what it's like if RGB were the primary colors. Cyan light to our eyes is a mix of green and blue. So Cyan reflects green and blue, and absorbs red (as far as our eyes care. Magenta light is a mix of Blue and Red, and absorbs Green. If we mix Cyan and Magenta, the cyan absorbs the red light, and the magenta absorbs the green light, leaving only Blue light for our eyes to see. Now, let's try using RGB as primary colors... Red is red, Green is Green. If you mix red and green, the red absorbs a lot of the green light, and the green absorbs a lot of the red light, leaving you with some gross colored paint (probably a dark brown, gray, or some other gross color) Cyan, Magenta, and Yellow are known as the subtractive primary colors. this is because when you mix two of these colors, they absorb (subtract) different colors of light, and the ones that each of them don't absorb gets let through, making a new color. (What I was explaining earlier) Red, Green, and Blue are known as the additive primary colors. This is because when you mix two of these colors together, they combine (add) to make more colors (ie Red plus Blue makes Magenta)", "First of all, what is light, what is paint, and what is color! What it light? Light is a wave in the electro-magnetic field... but it does not matter here. Light is also made of photons... but it does not matter here either. Light is an addition of multiple frequencies, and it can be decomposed in what we call a spectrum... or a rainbow! Ah, now we are talking! And if you want to understand color, you of course want to look at rainbows. What is paint? Paint gets its color from a dust that absorb some color, and reflect some other: pigments. The more selective/picky is a pigment, the more colorful it looks. What is color? Well, your eyes are actually not so good at seeing color, we are almost color blind, and of all the infinite different colors of the spectrum, we can only distinguish three groups: the blue-ish, the green-ish, the red-ish. But don't worry, our brain are there to help, and they can reconstruct an idea of the actual color, from those 3 information. So, what about yellow? Well, your brain see yellow if it see green-ish and red-ish but no blue-ish. Because, pure yellow, in the rainbow, appear like that to your eye. That mean we can trick the brain into seeing yellow: add green light and red light and you get yellow. Ok, that's the way your screen works, but it does not work with paint. Actually, you can't mix anything and get yellow, you actually need yellow in the first place. The primary colors of paint is yellow, cyan and magenta. Why? Well, paint do not produce light, it reflect or absorb it, and you have to put white light on it to see it. Yellow paint is a paint that absorb blue, and reflect red and green. Cyan paint is a paint that absorb red, and reflect green and blue. Magenta paint is a paint that absorb green, and reflect red and blue. So, if you want green paint you need to absorb red and blue light. If you put in cyan, you absorb the red, and you add the yellow, and it absorb the blue. And tada, only green remains! That is why we consider paint as substractive-coloring. If you mix all paints, you get black. While light is additive-coloring. If you mix all lights, you get white."], "text_urls": [[], ["https://www.infinity-printing.com/wp-content/uploads/2015/04/AdditiveVSSubtractive.jpg"], [], [], [], []], "score": [1088, 143, 32, 7, 6, 5]}}, {"q_id": "8sba3x", "category": "Repost", "title": "Why's it easier to turn a car's steering wheel when the vehicle is moving compared to when it's stationary.", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["e0y87tc", "e0y04m8"], "text": ["When the car is moving, the wheel can \"roll\" into a new angle. When the car is parked the wheel has to \"slide\" into a new angle. Rolling is easier than sliding - imagine pushing something along the ground, versus rolling something on the ground.", "Also keep in mind modern vehicles have power steering, if the car is stationary you might be moving a wheel on a turned off car, which gives no assistance to turning the tires."], "text_urls": [[], []], "score": [19, 7]}}, {"q_id": "8t0flj", "category": "Repost", "title": "Who manages the internet, and how does it work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["e13ojdo", "e13o3pw", "e14a2mq"], "text": ["It really depends on what you mean. The machines that make up the Internet are all owned by independent entities. Nobody manages the whole thing. Each network decides on their own if they want to connect with other networks (and how), and as long as there's some route between two different hosts, they can talk to each other. The protocols are largely managed by the IETF. The protocols are the \"languages\" by which computers on the Internet can talk to each other. The name system is ultimately organized by ICANN. If you want to get or resolve a domain name, like URL_0 , you're interacting with systems ultimately governed by them. ICANN also maintains the IP address space and a number of other components that are involved with unique identifiers on the Internet. For the most part, though, there isn't really a central Internet authority or anything like it. It's a cooperative endeavor among a lot of different groups of people.", "No one, really. The internet is just a bunch of private computer networks linked together. ISP's run networks more or less specializing in connecting all the networks managed by individuals and organizations together, but they don't \"manage the internet\" in any meaningful way.", "A lot of people are answering the first part of your question and ignoring the second, so I'll try to tackle the \"How does it work\" part. The internet is a complex beast, but at its core, it is just two computers talking to each other. When you surf the web, as you go from one website to the next, you are just switching which computer you are talking to out there. There is a lot of complexity that controls how you find these computers and how the routes are setup, but once you find who you are looking for, its just you and one other computer (and a bunch of routers/switches) moving your messages back and forth. So, how does your computer find the other computer in this huge network of computers? Lets compare this to something similar like mailing a letter. Every computer/phone or other device hooked up to the internet has an IP address (ex: [192.168.0.1]( URL_0 )) just like every house/business has a street address. If you want to talk to another computer, you need to know their IP address, just like if you mail a letter you need to know the street address of where you want it to go. But wait, I don't know reddit's IP address, how am I talking to this website? Something called DNS (Domain Name System) helps with that. Basically there is a server (many actually) that is responsible for holding a database of website names correlated to an IP address. Your computer asks them for help when looking for a website. Think of it like looking somebody up in the phone book to find their address. Okay so I have the IP address, now what? The internet is not just a bunch of personal computers and servers, there are also things called routers on it. You probably have one in your house. As their name might imply, they help to route internet packets to the right location. Think of them like your local post office. They may see some addresses and say \"Oh that's a local address, put it on tomorrows mail truck\" or \"Oh this address is in a different country, send it to our central shipping hub!\" In a similar way, your router (and all others on the internet) will help distribute traffic either to other local computers on the same network, or up to your ISP (Internet Service Provider) so that they (just more routers really) can send it to the appropriate location. IP addresses are setup in such a way that it is easy to divvy them up. This helps with the routing. So for example, one ISP might own addresses from 1-500 and another might own 501-1000. When you purchase internet service from them, they might give you address 45 to use. If you are a business, you might get a range, like 350-400. So if you are address 45 and you want to talk to address 547, the first ISP knows it needs to send the message to the second ISP because they own that address and they will know who they sold it to. Of course, this is a gross simplification of the process, but this explains the gist of how two computers find each other on the internet and start talking to each other. Keep in mind everything I wrote here usually happens in less than a second and current estimates suggest that over 24,000 Gigabytes of data are sent over the internet **per second**."], "text_urls": [["reddit.com"], [], ["https://192.168.0.1"]], "score": [89, 24, 24]}}, {"q_id": "8t8loi", "category": "Repost", "title": "Why do stars \"flicker\"?", "title_urls": {"url": []}, "selftext": "Just looking up into the night sky and wondering, what causes stars to flicker in brightness?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["e15kdek", "e15kcvr"], "text": ["On a clear, dark night, our eyes can see about 6,000 or so stars in the sky. They seem to twinkle, or change their brightness, all the time. In fact, most of the stars are shining with a steady light. The movement of air (sometimes called turbulence) in the atmosphere of Earth causes the starlight to get slightly bent as it travels from the distant star through the atmosphere down to us on the ground. This means that some of the light reaches us directly and some gets bent slightly away. To our eyes, this makes the star seem to twinkle. You will notice that stars closer to the horizon will appear to twinkle more than other stars. This is because there is a lot more atmosphere between you and a star near the horizon than between you and a star higher in the sky. Credit: URL_0", "I've searched tha seven seas fer an answer. Yer not alone in askin', and kind strangers have explained: 1. [ELI5: Why do stars flicker / twinkle? ]( URL_0 ) ^(_4 comments_) 1. [ELI5:Why do some stars flicker while others are stable? ]( URL_1 ) ^(_32 comments_) 1. [ELI5: Why do stars \"flicker\"? ]( URL_6 ) ^(_4 comments_) 1. [Why do stars appear to twinkle and flicker but the sun does not? ]( URL_2 ) ^(_2 comments_) 1. [ELI5: Why do stars appear to 'twinkle'? ]( URL_5 ) ^(_2 comments_) 1. [ELI5: why do stars flicker with different colors and patterns? ]( URL_4 ) ^(_3 comments_) 1. [eli5: why do some stars seem to flicker with different colors in the night sky? ]( URL_7 ) ^(_2 comments_) 1. [ELI5: What causes the stars to flicker when im looking at them? ]( URL_3 ) ^(_5 comments_)"], "text_urls": [["https://starchild.gsfc.nasa.gov/docs/StarChild/questions/question26.html"], ["https://www.reddit.com/r/explainlikeimfive/comments/1q9nmj/eli5_why_do_stars_flicker_twinkle/", "https://www.reddit.com/r/explainlikeimfive/comments/5017ey/eli5why_do_some_stars_flicker_while_others_are/", "https://www.reddit.com/r/NoStupidQuestions/comments/3zhos1/why_do_stars_appear_to_twinkle_and_flicker_but/", "https://www.reddit.com/r/explainlikeimfive/comments/29d4r1/eli5_what_causes_the_stars_to_flicker_when_im/", "https://www.reddit.com/r/explainlikeimfive/comments/1uxr48/eli5_why_do_stars_flicker_with_different_colors/", "https://www.reddit.com/r/explainlikeimfive/comments/5djwc8/eli5_why_do_stars_appear_to_twinkle/", "https://www.reddit.com/r/explainlikeimfive/comments/23n6rq/eli5_why_do_stars_flicker/", "https://www.reddit.com/r/explainlikeimfive/comments/1sssh6/eli5_why_do_some_stars_seem_to_flicker_with/"]], "score": [6, 5]}}, {"q_id": "8txghb", "category": "Repost", "title": "Why does popping my ears allow me to hear better sometimes?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["e1b069w", "e1b0bbg"], "text": ["Part of your hearing involves the membrane that is your ear drum. It helps to transmit vibrations to the inner ear so you can hear. When there is a pressure differential, or one side has a higher pressure than the other, the force of the higher pressure prevents the ear drum from vibrating. By equalizing the pressure, as in popping your ears, you have equal pressure on both sides, allowing the ear drum to vibrate better and make hearing easier.", "ELI5: Ear drum needs to wobble to hear properly, if you hold it still with pressure from inside, it doesn't wobble or wibble. Pop your ears, and the pressure goes away."], "text_urls": [[], []], "score": [11, 3]}}, {"q_id": "8udmx2", "category": "Repost", "title": "Why is our vision blurry underwater without goggles, but clear with them?", "title_urls": {"url": []}, "selftext": "Surely the only difference is that the water is touching our eyes. Why does that small bit of air allow us to see clearly?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["e1eley0"], "text": ["Humans are land-dwellers, and our eyes evolved to see in Earth's atmosphere. Water bends light differently from how this mix of gases does, so what we see is blurred in water compared to air."], "text_urls": [[]], "score": [12]}}, {"q_id": "8usjc4", "category": "Repost", "title": "How exactly does inflation work? If I held onto \u00a350,000 now and did not earn a penny more for fifty years, for example, do I STILL have \u00a350,000, or does it\u2019s \u201cworth\u201d depend on other factors?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["e1hrjd2", "e1hrt1s"], "text": ["If you had a pile of 50,000 one-pound notes, in 50 years, you'd still have a pile of 50,000 one-pound notes. Neglecting the possibility that they would be more valuable than their face value to collectors, they would still be worth 50,000 pounds. But those 50,000 pounds would have less buying power; where you could (for example) buy a nice car for that now, in 50 years, you would only be able to get a cheap car.", "You will still have 50,000, but you will be able to buy less with this money. In 1980 loaf of bread was worth 0.715$, now it costs 1.966$. And such trend goes for everything. So your amount of money is the same, but you will be able to buy less with it. Source for prices: [ URL_0 ]( URL_0 ) EDIT: correct link"], "text_urls": [[], ["https://data.bls.gov/cgi-bin/surveymost?ap"]], "score": [12, 6]}}, {"q_id": "8uv57u", "category": "Repost", "title": "What's this whole thing about CO2 shortages in Europe?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["e1idsha", "e1idk6w"], "text": ["Pure CO2 (under pressure) is injected into drinks to make them bubbly, used in fire extinguishers, and apparently in certain types of baking. It\u2019s naturally produced by yeast in baking and alcohol production, but for a number of reasons, it\u2019s easier to add more. While the atmosphere has more CO2 than we wish it did, and it\u2019s produced in many ways, it\u2019s not easy to grab (only) CO2 from the air and pack it into a can. It\u2019s not brain surgery but it requires machinery and materials. If companies aren\u2019t making enough of it, maybe because people want more of it than they did before, you end up with a shortage. This happens all the time with all sorts of goods, but usually resolves after a little while. Because people *want* to buy it, making and selling it provides a good opportunity for profit. But it takes time for people/companies to start producing it.", "CO2 is produced as a byproduct of some factory processes, that's the cheapest source for beverage use. It's summer, beverage consumption is up and factory workloads are low. This causes a supply low every year, but this year is worse that the recent past."], "text_urls": [[], []], "score": [8, 3]}}, {"q_id": "8va7in", "category": "Repost", "title": "Commercials for live events?", "title_urls": {"url": []}, "selftext": "How do ads play for live events like award shows if they are suppose to be live? Days before live events I see commercials for them and I don\u2019t understand how this is possible if the event is suppose to be live, and they don\u2019t look like last years either. I\u2019ve always been curious about this.", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["e1lq5b5", "e1lqaha"], "text": ["Many of these events are recurring or there are similar events. So for example if it going to be a sports event, they might use last-years footage to spice up that commercial. If it going to be something new, the commercials usually feature participants or previously taken footage of participants with some generic background content such as applauding masses, cheering fans, generic doode in winner pose (these clips are like the stockphotos of tv commercials). Or they show the actual location, like the concert hall, the stadium, or whatnot.", "Some like the MTV movie award is not live but was broadcaster 2 days later and is likely cut down in time to make it better TV. So they can use real footage for 2 days. Other like the academy awards is live. So you cant use any real footage for the event. A important part to remember it that the nominees are public in advance and host i known and the stage is likely finished many days in advanced. So you can in advance film segment with the host and also include the well now nominated stars in the. So the answer is there can't be any footage from the ceremony if it is live but you can shoot special segments for the commercial that look like the show in advanced. You can also use old footage because it is not oblivious that it is not new. For sport you can use footage from games earlier in the year."], "text_urls": [[], []], "score": [9, 3]}}, {"q_id": "8vc34d", "category": "Repost", "title": "why do bicycles have to be on the road instead of the side walk?", "title_urls": {"url": []}, "selftext": "I understand how a bicycle can be seen as a vehicle; but all I can keep asking myself is: would you rather have a cyclist hit a pedestrian or a car hit a cyclist?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["e1m6c76", "e1m6uoi", "e1madn3"], "text": ["I live in a city where people walk long distances to work from where they park. I can\u2019t stand when bicyclists are on the side walks. When they\u2019re on the roads at least they can go a closer speed to a slow car. But on sidewalks, bicyclists go so much faster than the average walking human, people have to jump out of the way, it\u2019s horrible. They should definitely only be allowed on the roads.", "Where I live in Indiana there's hardly any sidewalks at all, let alone bike lanes, so I would assume that's taken into account with the laws about using a bike as transportation", "It actually depends where you live. I live in Austin, TX, and as far as I know, we are legally allowed to ride on most every sidewalk, with the exception of a few in the downtown area (high foot traffic) and around our university campus (also high foot traffic). Other than that, I can ride on any sidewalk I choose, and I regularly do, depending on where I am and how dangerous I judge the street to be. I just keep my speed MUCH slower when pedestrians are present and make sure to let them know that I'm coming around them, when I pass. Now, if there are a LOT of people on a sidewalk and I don't care to ride in the street, I'll usually just stand on one pedal and coast slowly with the pedestrians, and simply hop off and walk, if it gets too crowded."], "text_urls": [[], [], []], "score": [7, 5, 3]}}, {"q_id": "8vkmjs", "category": "Repost", "title": "Why does liquid stay level on a plane when the plane turns?", "title_urls": {"url": []}, "selftext": "I was just on a plane, and as the plane turned, the drink in my cup on the tray table stayed level. Why is that?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["e1o2ihv", "e1ou1xl"], "text": ["Because the G-forces are still \"down\" from your perspective in the seat. If the plane rolled, the water would spill, but the pilot has a lot of experience doing this and is pulling a \"1G turn\" meaning that gravity appears mostly unaffected to passengers. It's accomplished by turning rolling and pitching (one wingtip down, nose up) to turn and using appropriate rudder to keep the plane from slipping or sliding in the turn.", "Attempt at ELI5 answer. Imagine you are in a car driving around a bend and you are holding some sort of pendulum. It could be a yo-yo, a conker, basically any weight on a string. That pendulum will swing out a certain angle (depending on your speed and the tightness of the turn). An aeroplane simply rolls its body to the same angle, so that the weight force always acts straight down from your point of view sitting in the plane."], "text_urls": [[], []], "score": [13, 3]}}, {"q_id": "8wmj53", "category": "Repost", "title": "Why do cars make that clicking sound when you turn them off?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["e1wn6sa", "e1wnrdp"], "text": ["As the hot metal parts cool they are shrinking microscopically. Since they are all bolted together this process can be a bit noisy, that's what the ticking sound is, or at least that's how it was explained to me.", "Engines get really hot from the combustion (explosions!) of compressed gas vapour and oxygen in the engine. Heated metal expands (gets bigger). Turn the engine off and the engine cools. When it cools it contracts (which is the opposite of expanding). Not all parts cool at the same timetime. Some parts cool faster than others. But all these parts are bolted together. This contraction of the different metals makes a pinging, or clicking sound as the pull on each other. Redditkind, feel free to correct or clarify."], "text_urls": [[], []], "score": [7, 3]}}, {"q_id": "8yfs9s", "category": "Repost", "title": "what makes our veins greenish blue when our blood is red ?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["e2ak896"], "text": ["Yarr! Yer not alone in askin', and kind strangers have explained: 1. [ELI5: Why do our veins appear blue? ]( URL_5 ) ^(_15 comments_) 1. [ELI5: So if blood isn't blue inside the veins because of lack of oxygen then why is it that veins seen through the skin sometimes appear blue? ]( URL_1 ) ^(_18 comments_) 1. [ELI5: why do our veins appear blue/green through our skin? ]( URL_3 ) ^(_4 comments_) 1. [ELI5: Why is blood red but do our veins look blue? ]( URL_0 ) ^(_4 comments_) 1. [ELI5:What are these blue looking veins under my skin? ]( URL_2 ) ^(_16 comments_) 1. [ELI5: Why are my veins blue and green if my blood is red? ]( URL_4 ) ^(_7 comments_)"], "text_urls": [["https://www.reddit.com/r/explainlikeimfive/comments/2r5f4e/eli5_why_is_blood_red_but_do_our_veins_look_blue/", "https://www.reddit.com/r/explainlikeimfive/comments/2j1kj5/eli5_so_if_blood_isnt_blue_inside_the_veins/", "https://www.reddit.com/r/explainlikeimfive/comments/2o7zpb/eli5what_are_these_blue_looking_veins_under_my/", "https://www.reddit.com/r/explainlikeimfive/comments/4u609b/eli5_why_do_our_veins_appear_bluegreen_through/", "https://www.reddit.com/r/explainlikeimfive/comments/1rofvp/eli5_why_are_my_veins_blue_and_green_if_my_blood/", "https://www.reddit.com/r/explainlikeimfive/comments/2b1ip1/eli5_why_do_our_veins_appear_blue/"]], "score": [10]}}, {"q_id": "90b2ho", "category": "Repost", "title": "Why are you not supposed to mix old and new batteries in a device?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["e2p4dvt"], "text": ["If you have a device which is pure resistive, or close, it will continue to draw current until the voltage goes to zero. The total voltage will be the sum of the voltage across all batteries. Let's say we have 3 new batteries and one old one. If we leave the device on, the total voltage is soon 0V. The three new batteries are 1.5V each. This means that the old battery is at **minus** 4.5V. It's going to corrode triple-time, and leak damaging liquid all over the battery holder."], "text_urls": [[]], "score": [10]}}, {"q_id": "90ivph", "category": "Repost", "title": "why does yellow seem brighter than other colors?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["e2r20sm", "e2r1ptk", "e2r1v32", "e2r4a5d", "e2r9sao"], "text": ["You have 4 basic types of light receptors in your eyes. Rods, Red Cones, Blue Cones and Green Cones. The Rods are used for night vision and edge detection, and the Cones detect the color they are named for. Different cones have different sensitivities, and the Green Cones are most sensitive, followed by Red, followed by Blue. Yellow colors activate the Green and Red cones, which are the most sensitive and 2nd most sensitive cones and they add together, generates the largest signal given the same number of photons.", "It always doesn't. But we don't realize it. Same with orange. It has to do how we categorize colors. When you have green and make it darker, you have dark green. When you have red and make it darker, you have dark red. When you have blue and make it darker, you have dark blue. When you have purple and make it darker, you have dark purple. But when you have yellow and make it darker, we don't consider it dark yellow. [We consider it olive green.]( URL_1 ) Yellow in RGB is R: 255, G: 255, B: 0. So halving the brightness of yellow gets you dark yellow. R: 128, G 128, B: 0. It appears olive green to us. Not yellow. We don't consider olive green to be yellow, even though it technically is dark yellow. And when you have orange and make it darker, we don't consider it dark orange. [We consider it brown.]( URL_0 ) Orange in RGB is R: 255, G: 128, B: 0. So halving the brightness of orange gets you dark orange. R: 128, G 64, B: 0. It appears brown to us. Not orange. We don't consider that brown to be orange, even though it technically is dark orange.", "[Eyes happen to be most sensitive for green and yellow]( URL_3 ) But why?!! [That curve closely matches the light from the Sun that reaches the ground.]( URL_0 ) But why do they match?! Because it is practical to sense the strongest light the best. [Actually our eyes have also night mode. Called scotopic vision. With WAY more sensitivity for blue.]( URL_1 ) But it only kicks in when there is very little light. That is why everything seems blue when it is dark. Why blue? This happens because oxygen in atmosphere changes the direction of blue light, so even when sun isn't visible, some of the blue rays arrive to us, after many changes in direction. Finally, on screen yellow will look extra bright, because it is created by lighting *BOTH* red and green. [A picture of magnified LCD. Step back to see yellow emerge from green and red.]( URL_4 ) ^^^^^Original: URL_2", "There are some good responses so far, but I haven't seen one of the simplest: Contrast. The highest contrast color pair is yellow and black. (Followed by yellow and blue, followed by black and white, then blue and white.) You'll see this expressed in license plates, for instance: NY is black/yellow. California used to be black on yellow, then yellow on black, then yellow on blue and now blue on white. Yellow \"stands out\" against a world of mostly darker colors. I am not sure if you mean yellow seems \"brighter\" in general, but our rods and cones process visual information relatively, looking for contrast between objects (and their colors) to aid in pattern recognition, which helps process information more efficiently. I know all of this only as a layperson because my work is about processing visual information.", "It has to do with how we classify yellow as a color, as well! Not often do we see \"dark yellow\" because it just turns into a different color. Speaking from the art perspective, if you shade yellow (that's adding black to yellow), you get a color that has more of a green hue. When you tone a yellow (that's adding the complementary color to yellow, and in this case, it's purple), you get a brown color. The only real way we can mix yellow with something and keep its yellow hue is with white, but doing so will desaturate it. Moreso, yellow is a primary color. You cannot mix colors to make yellow. So simply speaking, yellow is brighter than other colors because we call it something else when it ISN'T the bright yellow we know it to be."], "text_urls": [[], ["https://i.imgur.com/X7XS5l7.png", "https://i.imgur.com/yT5FEOc.png"], ["http://www.handmadeinpa.net/wp-content/uploads/2012/02/SA_sun_550SA.jpg", "http://www.handprint.com/HP/WCL/IMG/lumeff3.gif", "https://www.reddit.com/r/explainlikeimfive/comments/28s1fd/eli5_why_does_yellow_look_brighter_than_red_or/cie05cl/", "https://en.wikipedia.org/wiki/File:Eyesensitivity.svg", "http://farm8.static.flickr.com/7253/6899963862_52c45a38df_m.jpg"], [], []], "score": [1457, 181, 97, 10, 3]}}, {"q_id": "91ngoj", "category": "Repost", "title": "How were hand-drawn cartoons transfered to newspaper printers before scanners were a thing?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["e2ze51r", "e2zes71"], "text": ["There was a thing, coincidentally called a \"scanner\". Gadget inventors put all their imagination in the gadget, names not so much. You put the picture on one drum and a thin piece of metal on another drum. Then you turn the drums and the scanner looks at a spot on the paper. If it's white, nothing happens and if it's dark a little hole gets drilled in the metal. The process was called screening or half-toning. Some very fine line art was probably etched or lithographed, but the run of the mill newspaper had a scanner so that they could have art in ads.", "This was one of my first jobs on my college newspaper just before we went digital using desktop layout (early 90\u2019s). Photostatic cameras were used to take a picture of them on film, but at the same time they would, through the use of filters, turn the darker areas into a series of dots. At the same time they could be sized up or down based on how far the camera was positioned for the subject image. Think of these basically like a really big, low magnification microscope with extremely bright halogen lights shining on the image and a lens at the top with photo paper you\u2019d expose. The resulting photograph would then be ready for the printers. (Edited for late night grammar)."], "text_urls": [[], []], "score": [3, 3]}}, {"q_id": "924ejg", "category": "Repost", "title": "Why are FM radio stations only found at odd decimal places...?", "title_urls": {"url": []}, "selftext": "e.g. 88.5, 101.1, as opposed to 88.4 or 88.6...?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["e338980"], "text": ["Presumably this is a decision by the FCC in America, its not the case elsewhere. Eg here in the UK we have odd and even decimal frequencies. Obviously adjacent frequencies are not in close proximity, but they're not fixed to only odd decimals."], "text_urls": [[]], "score": [4]}}, {"q_id": "925m1w", "category": "Repost", "title": "How can a single fiber optic cable(or other data line for that matter) carry multiple signals at the same time? What keeps all the information being transmitted from mixing and turning into data gobledygook?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["e337pjr", "e337r3x"], "text": ["Imagine Morse code. It requires just one color of light to signal information with it. Now imagine many different colors of light flashing different Morse code messages at the same time. Despite them being together, you can analyze which colors of light are blinking when, and decipher that specific message. It\u2019s like a different Morse code language for each message. So computers at each end of the fiber optic cable have designated a certain stream of data with a certain color of light. They can communicate forwards and backwards, and multiple messages all at the same time.", "1. Different colors of light carry different channels \u2014 just the way different radio frequencies can carry different stations. 2. Each channel is divided into brief \"packets\" of digital data, one after another, and each packet starts with a numeric \"address\" so they can be sorted by recipient."], "text_urls": [[], []], "score": [7, 3]}}, {"q_id": "92cgd4", "category": "Repost", "title": "How are males and females born at such an equal rate?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["e34m7i3", "e34mgue", "e34qz1e"], "text": ["When a child is conceived, the sperm cell and the egg cell each contribute one chromosome. If the child gets two X chromosomes, it becomes a woman and if the child gets an X and a Y, it becomes a man. The egg cell, coming from a woman, can only give an X chromosome. The sperm cell, coming from a man, can give either an X or a Y. This results in a 50/50 chance, and over a large sample size, a 50/50 split of male and female at conception. EDIT: Keep in mind there are sex-based happenings after conception that can affect whether that embryo makes it to birth and out of infancy. In real life the ratio isn't exactly 1:1. There are also some cases where the person ends up with too many chromosomes, for example, having three chromosomes is the cause of Downs Syndrome.", "Natural selection often favors birth rates near to equilibrium. Consider if some species has a preference for female births. So you have more females than males. This means any given male has a better chance of passing on his genes than any given female (since he has more opportunity to find more mates and produce more offspring, there's ladies all over the place and not much competition!). So the male is more likely to pass on his traits. This means that selection will favor any traits that bias births in favor of males, as that would result in more males which in turn results in more opportunities for those traits to be passed on. However, as the ratio approaches 1:1, the advantages of those male-preferential traits diminishes, since their overabundance of opportunity shrinks. TLDR: If there's a lot of one sex, then the best opportunity to pass on your genes is to make a lot of the *opposite* sex, since then you are taking advantage of the opportunities, instead of fighting the competition. So traits that favor this will tend to win, pushing towards 1:1. STLDR: If everyone wants bread and milk, and everyone else is selling milk, you should sell bread.", "[Minute Earth]( URL_0 ) Did a pretty solid video a few years back explaining this rather well but also [It\u2019s Ok to be Smart]( URL_1 ) did one to explain the animal kingdom balance and why it's the way it is"], "text_urls": [[], [], ["https://youtu.be/3IaYhG11ckA", "https://youtu.be/C3dCWxxVhVc"]], "score": [11, 5, 3]}}, {"q_id": "92kjll", "category": "Repost", "title": "Why do movies shot in 24 fps seem so much smoother than 24 fps?", "title_urls": {"url": []}, "selftext": "For example, if you run like a video game or a animation in 24 fps then it's studdery as hell. But movies and tv shows appear smooth.", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["e36egcd", "e36u1mr"], "text": ["Short answer: blur. When you shoot a scene at 60 fps, you get faster shutter speed and less blur. When you shoot 24fps, you get slower shutter speed, and more blur in the shot. Play back a scene at 24 fps which was shot at 24 fps, and there is more visible motion in each individual frame. Blur. Play back the same scene at the same rate which was shot at higher speeds, and each visible frame is sharper, making it seem as though it's stuttering.", "Cameras capture their scenes by opening a shutter for a period of time, exposing a film or image sensor to capture information about the scene. Each frame represents a period of time and moving objects will be shown as a blurry smear across the frame. Computer renderings are made of a calculated theoretical instant. As a single instant there can be no motion and moving objects are as clear as if stationary, and are only in one place. So you see a frame from a computer rendering contains less information than that of a camera, and the disconnects make it look jerky. A normal camera at least connects the ends of motion blurs while the rendered frames just jump from place to place."], "text_urls": [[], []], "score": [13, 7]}}, {"q_id": "934jwg", "category": "Repost", "title": "How does vegetation grow on volcanicly formed islands if they're just mounds of rock?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["e3aimv9", "e3ajb95", "e3aje6o", "e3aiux1"], "text": ["Wind blows dust to the islands accumulating soil overtime from continents near and far. Seeds catch a ride on birds, floating wood, or debris making the journey across the ocean.", "Jesus christ Marie, they're not rocks, they're minerals. Volcanic rock tends to have plenty of iron, zinc, and other important minerals to support healthy soil. Once moss / lichen / other rock-loving flora and the like start covering the island, and errosion builds a layer of soil, what you're left with is an extremely fertile soil filled with extra minerals. This isnt a quick process. We're talking up to thousands of years before the minerals break down enough, and plant matter decomposes in large enough quantities that the topsoil is deep enough to house large flora that you see on many older volcanic islands. And for those who might wonder how the plants get on the island, there are many ways. Some straight up have seeds / spores ride the air currents. Some ride on migratory birds, float on the ocean, and so-on. Survival of the fittest favors the adaptably creative.", "What led me to ask this was the island of Pulau Tiga. Formed from a volcanic eruption in 1898 so only 120 years ago. Yet the entire island is covered in thick vegetation. Just thought it would take a lot longer to get to that stage", "It can start with lichens or moss or even some species of plants that can grow off nutrients from rainwater, volcanic ash, or other organic matter that has accumulated over time on the rock. These plants then eventually die, leave behind their organic matter and eventually over hundreds or thousands of years or even longer bigger plants can eventually grow."], "text_urls": [[], [], [], []], "score": [47, 19, 18, 3]}}, {"q_id": "93lqvz", "category": "Repost", "title": "How are speed limits determined?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["e3e7z51"], "text": ["They are determined in the US by safety factors, and 85 percentile speed. The 85th percentile speed is, in the area of question, the speed in which 85% of cars do not exceed. The safety factors are risks that put people in danger like road curve, uphill and downhill speed, etc."], "text_urls": [[]], "score": [6]}}, {"q_id": "9592no", "category": "Repost", "title": "why do pennies exist? Considering that the cost of producing them surpasses their value, aren't we just wasting money?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["e3r075p", "e3r0htr", "e3qz7op", "e3qy2gt", "e3qxx53"], "text": ["The production of physical currency by the government is not primarily a money-making enterprise. Instead the desire is to provide a medium of exchange of value for the population to use, facilitating economic activity. Pointing out that a specific unit of physical currency costs more to produce than its face value is entirely irrelevant to the issue of if it should continue to be produced. It is sort of like noting that traffic police don't take in enough in issued tickets to pay their wages. Even if that is true, so what? Traffic police are not a for-profit enterprise.", "So, lets get the Jared Zinc conspiracy theory out of the way. Jared Zinc is the main zinc producer in the US (and pennies are predominantly made out of Zinc). Jared Zinc spends < $200,000 in lobbying every year, last year it spent $20,000. The most it ever spent was $340,000 in the 2012 Presidential election. These are absolutely trivial sums. To put this in perspective, the coal industry has historically spent in excess of $25 million dollars a year, and peaked at over $40 million in the 2008 Presidential election. A lot of the claims surrounding Jared Zinc center on the fact that it in 2006 it tried to publicized a report that it created which showed the \"benefits\" of the penny to the American economy. Of course nobody took this report seriously except for the handful of people that want to claim that some grand zinc conspiracy is behind the retention of the penny. The real reason that the penny is retained is because it doesn't cost much to make and there are very real costs in abandoning it. Every year the mint \"loses\" about $30 million dollars on the raw materials used to produce the penny. This may seem like a lot but you have to keep it in the context of the mint, which is self funding and designed not to make a profit. Despite losing $30 million on the penny, the mint makes approximately $600 million on currency production, most of which comes from the quarter. But again, the mint isn't designed to make a profit, so what does it do with that $600 million in profit? If you think it goes to the government you're wrong - the mint uses that money to produce collectible coins which it then sells to the public at a loss. So if the mint got rid of the penny, you wouldn't see the government suddenly get $30 million richer. Rather, all that would happen is you would see the price on US mint produced collectible coins go down a bit - which you can buy [here]( URL_0 ). And again, there are very real costs to getting rid of the penny. Every vending machine in the country would need its coin system either replaced or, if the machine allows, updated. Stores would also need to update their registers to round to the nearest 5 cents. And the government would need to generally educate the public on the fact that the penny is going away. Then you have the fact that the mint is generally cautious about making any currency changes after the $1 Sacagawea dollar - which was the mint's attempt to produce a $1 coin to replace the dollar. They produced billions of dollars of the coins, and then everyone complained and no one used them. The lesson that the mint took from that is that people are generally happy with the currency currently available and are highly resistant to change. So at the end of the day the only benefit of replacing the penny is that the price on US Mint collectible coins would come down a bit. Conversely, replacing the penny would entail imposing *some* costs on society and may very well generate sufficient backlash to force them to reintroduce the penny anyways.", "It costs more than 1 cent to make 1 penny, but it's not a one shot item. A single penny gets used over and over and over.", "The simple answer is lobbying. One company, Jarden Zinc Products, supplies the US Mint with all of their zinc, and spends lots of money to keep the penny.", "They are a waste of money, but they continue to exist because of government inertia. It would require an act of Congress to get rid of pennies, and Congress isn't capable of doing much of anything these days besides cutting taxes for rich people, so it doesn't get done. It would also require some time and expense by businesses who would have to adjust to the new practice of rounding all transactions to the nearest 5 cents, but still, getting rid of pennies would probably save businesses money, by not having to waste time and fiddle with them anymore. Ideally we'd go ahead and get rid of nickels and quarters too, and just use dimes and 50-cent pieces, round everything to the nearest ten cents. Nickels cost more to produce than they're worth as well. And when the half-cent coin was abolished in 1857 (for being worth too little to bother with), it was worth the equivalent of 10 cents today. There are other very low-value coins in the world that probably ought to be abolished too. The Brazilian 5-cent coin is worth about 1.1 US cents (notice they already got rid of their 1-cent coin). The Japanese 1-yen coin is worth about .9 US cents. The half-rupee coin in India is worth .7 US cents, and the 1-kopek (1/100 of a ruble) Russian coin is worth just .16 US cents."], "text_urls": [[], ["https://catalog.usmint.gov/on/demandware.store/Sites-USM-Site/default/Default-Start?_ga=2.2486004.536427201.1533625936-799552922.1533625936"], [], [], []], "score": [13, 8, 7, 7, 6]}}, {"q_id": "95zsxu", "category": "Repost", "title": "I just bought a 20-year old bottle of Brandy. How is this economically viable to the producer? How do these companies even start when they can't sell their products for X amount of years?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["e3wobsy", "e3wpb7l", "e3wpj4r", "e3wvb7k", "e3wqli8", "e3wszaz", "e3wrc4r", "e3wnw17", "e3wsqzq", "e3x2dk5", "e3wte4e", "e3wphrc", "e3wrwp0"], "text": ["By having a wide product line. Start by making 100 drums of fresh unaged. Don't sell any the first year. year2, sell 90 of those as cheap stuff, produce 100 more drums of fresh unaged. You now have 10 of 1 year old, and 100 fresh. Year 3, sell 90 of 1 yr old as cheap stuff, you now have 10 2yr, 10 3yr. Produce 100 more fresh. Somewhere round 5 year. You can start selling 1-2 barrels of medium grade 5 year stuff. Leaving you with 7-8 barrels to keep on aging Repeat for 30 something years", "Most new distillery operations will start off making non-aged spirits like vodka, rum, or gin these can support the business while they age their other products.", "Many distilleries will come to an agreement to buy aged products from other suppliers until they've made their own.", "I don't know how common it is, but a whiskey destillery in Sweden used and alternative I have not seen here yet. They basically did \"pre orders\" and made the aging process a part of the product. They sold small (like 5-10 liter) casks and put it in storage. Then they let the owner (and whoever they brought with them) come in and taste it something like every 6 months to experience how it matured. Then they bottled it and put on a label you choose when you thought it had mature enough. It seemed like quite a hit among hotels and bars in the local area as well as whiskey enthusiasts. They made all the money directly, and the small casks gave a matureing time of about 2-5 years so the customers did not have to wait forever.", "It's actually a really good long term investment because of inflation. They are getting a huge profit margin on these by manufacturing at 1998 prices and then selling for even higher than the standard 2018 prices for the non-aged bottles. They typically don't set aside ALL of what the produce for 20 years, just a small percentage, and then they sell the rest, so it's kind of like a retirement fund, and they could theoretically shut down the factory and continue selling from storage with virtually no overhead", "The other answer is that the person who starts the company is rich by other means and it was an investment for their wealth.", "You're getting a lot of good answers, but a related topic to consider (as far as long startup times) is that a grafted pecan tree (the faster way to do it) takes 4 years to even start producing, and doesn't reach full production until 7-10 years. The reason both can be done is partly that there is a balance between risk & reward. It's a risk starting an orchard of pecan trees, and it's a risk setting aside a barrel of brandy for 20 years. This is balanced, however by the expected reward. People are generally happy to spend much more to buy pecans than peanuts, and people are generally happy to spend much more for aged brandy than for vodka.", "I\u2019d guess that they start out making things that they don\u2019t plan to age and then once they see some growth or success they begin putting in the time capsules or whatever you want to call em", "To answer the second part of your question, new companies buy other company's already aged brandy and rebrand it as their own. Typically from a mega-distillery.", "There are private equity funds that buy the rights to a certain vintage or type of alcohol and pay the producer upfront and wait those many years to collect revenue. Example : URL_0", "A whiskey distillery I went to in Scotland upped their income buying the odd barrel from other distillers - some individual barrels can be VERY expensive. They can buy a 30 year old barrel anytime, so even in your first year you can sell other product that will keep you afloat.", "It takes a lot of money and time to start a business that sells aged products. Mostly, you have to be able to eat the costs of production without any revenue for a few years. You can make a little money doing work for other established companies & selling unaged products (eg - vodka) but you've basically gotta go 5 years before you can ever sell anything.", "Not an expert in alcohol production but a little bit of critical analysis: Most of the costs will be labour, plant, distribution and advertising. As somebody else pointed out they don't sell all of the produce at 20 years so the sunken cost of the material to produce the significantly lower quantity of aged stuff will be negligible compared to the 3 or 5 years product cycle. You will likely use the same distillation process for the same product except for the aging duration."], "text_urls": [[], [], [], [], [], [], [], [], [], ["http://bacchuswinefund.com/"], [], [], []], "score": [1339, 283, 92, 59, 22, 17, 5, 4, 3, 3, 3, 3, 3]}}, {"q_id": "965lzf", "category": "Repost", "title": "Double Slit Experiment.", "title_urls": {"url": []}, "selftext": "I have a question about the double slit experiment, but I need to relay my current understanding of it first before I ask. ___ So here is my understanding of the double slit experiment: 1) Fire a \"quantumn\" particle, such as an electron, through a double slit. 2) Expect it to act like a particle and create a double band pattern, but instead acts like a wave and causes multiple bands of an interference pattern. 3) \"Observe\" which slit the particle passes through by firing the electrons one at a time. Notice that the **double band pattern returns, indicating a particle again.** 4) Suspect that the observation method is causing the electron to behave differently, so you now let the observation method still interact with the electrons, but do not measure which slit it goes through. Even though the physical interactions are the same for the electron, it now **reverts to behaving like a wave with an interference pattern.** ___ My two questions are: **Is my basic understanding of this experiment correct?** (Sources would be nice if I'm wrong.) and also **HOW IS THIS POSSIBLE AND HOW DOES IT WORK? It's insane!**", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["e3xwkqj", "e3y7ort", "e3xx1z2", "e3yaiqz", "e3y2ugk", "e3y4for", "e3y631g", "e3y8wg0", "e3z378g", "e3y4s9o", "e3yjbkg"], "text": ["Typically a photon is used rather than an electron, since that makes figuring out the wavelength (which determines the pattern) a lot easier, but otherwise you got it right. As far as why it works that way, we have no idea. Well, we have lots of ideas, but no solid answers. We do know that if you split a photon into two entangled photons (each with half the energy) you can observe effects that appear to violate causality, in that measuring one particle ***after*** the other has gone through a double slit experiment changes the result of the experiment retroactively. Unfortunately it does so in a way that makes it useless for sending messages to the past. When someone figures it out that's pretty much a guaranteed Nobel prize. Edit: \"appear to\"", "You're close but a little bit off: - If you fire a bunch of electrons one-at-a-time (like your point #3), but you make no effort to figure out which slit they went through, you will see the interference pattern start to form - The only way you get the double-band is if you try to \"measure\" which slit the electrons went through, even retroactively (IE you measure them *after* they would have already passed through the slit) - What's even more mind-blowing is the idea of what-they-call \"Delayed-Choice Quantum Erasure\" Here's a quick explanation of Delayed-Choice Quantum Erasure: So let's say you fire photons one-at-a-time through the slits at some sensors. You get wave interference pattern because you're not trying to determine which slit they went through. So you add polarized filters *after* the slits. Now you can tell which slit the photon went through based on whether it has up-down or left-right polarization. Well now your sensors will only detect particles. Cool so far, right? But maybe the polarization itself messed up the wave behavior, right? Here's where it gets weird... If you \"forget\" the information about which slit it went through, it goes back to being a wave again! So in the above example, you place another filter in each path that \"scrambles\" the light polarization again. Now the double-band turns back into a wave, because you once-again have no way of knowing which slit it went through. And it works even for huge distances! So it's like the universe is somehow able to know that you will *eventually* be able to determine which slit it went through, and so it collapses to a particle. But if it knows that you will *eventually* \"forget\" that information, it stays as a wave. EDIT: [Here]( URL_0 ) is a link to a PBS SpaceTime video that explains it, although definitely not ELI5...", "Also, might be a dumb follow-up, but what does \"observe\" mean in the context of this experiment?", "You missed the crucial point! Even if you fire one electron at a time, you still get the multiple-band interference pattern: Each single electron will produce a single point on the screen, but after you have fired many electrons, one after the other, all the points together form the wave pattern. The fact that each electron forms one point shows you that they are particles, i.e., very small objects that are at a specific location in space. However, the spacing of the wave pattern depends on the distance between the two slits. So, how can a single electron \"know\" that distance? As a small particle, it cannot \"see\" or \"feel\" the other, far away slit, when it went through one slit. Clearly, the electron has \"spread out\", filling the whole space, hence \"sensing\" both slits, and \"interfering with itself\". This shows you that the electron has passed through the slits as wave, i.e., as a spread-out entity which is not at all at one single specific location in space. Only when reaching the screen, and thus getting \"observed\", the electron wave \"collapses\" to a single point that lights up on the screen. If you only look at the case of many electrons fired at the same time, you might argue that some electrons went through one slit, some through the other, afterwards they met, affected each others flight path, and thus somehow produced the specific interference pattern with it curious dependence on the distance of the slits. But once you notice that the same happens with only one single electron present at a time, you can no longer deny that it is really both a wave and a particle, both everywhere and yet a single point-like thing.", "Yep you've got it right and the reason it's such a big thing is because nobody knows why yet. Theres lots of theories but no sure answer. But hey, If you can figure it out there'll be a Nobel Prize waiting for you.", "This experiment is a good example of the scientific method at work. There's a theory, an observation and then an experiment to confirm the theory. The experiment does not seem to prove the theory, and therefore we test again to develop a new theory. So you state a theory, that a photon is a particle or a wave. You test that and find that it displays indications that it is both a particle and a wave. or that it's neither a particle or a wave. Also, there's an indication that observing the experiment affects its outcome. > HOW IS THIS POSSIBLE AND HOW DOES IT WORK? It's insane! That's just it. The experiment indicates that we don't really understand what's going on at all. It's apparent that the photon acts as both a particle and a wave. So it's either some new third thing that we don't understand or us observing it changes it between a particle and a wave, but we don't understand how that could be happening. This is the basics of how science works. We've observed, something that we don't understand how it works. We have a few ideas but they don't appear to be correct and it's easy to disprove one idea or another about what's going on. Now we need to develop theories about what we've observed. Since our existing knowledge about the universe seems counter-indicated by this experiment, it means that there's something we are missing. So it leads us into the study of quantum particles and why they don't conform to our known \"laws\" of physics. Do the laws need to be adjusted, is everything we think we know actually wrong or is there some kind of other explanation.", "1. Yes, but your concept of observe is incomplete. Firing an electron one-at-a-time doesn't really help you know where the electron went. To observe which slit an electron went through, you'd shine a light just behind the slits, and the electron would collide with a photon which is detectable. 2. Nobody knows, we just have theories. This is one of those things that, if it doesn't blow your mind, you don't really understand it. The way I tend to think of it is that they travel as probability waves, and events can occur which cause them to collapse back into a single point again. Then they'll travel as a probability wave again. Probability waves can interact with themselves and each other, hence the interference pattern when it passes through two slits. So when an electron interacts with a photon in the case of us \"observing\" them, they collapse into a point, then go back to traveling as a new probability wave from that point. So if you cause them to collapse back to a point on the other side of the slits, then you lose the interference pattern caused by the slits. Note that in my internal idea of what's going on, the speed of light or the direction of time is being violated. The entire wave of probabilities collapses at once, no matter how large it is. So either it happens at infinite velocity, or something is going backwards in time and removing the rest of the probability wave.", "There is actually a simple deterministic explanation for it that is easily simulated with oil droplets. It's just standard interference patterns on vibrating particles that is explained with pilot wave theory (De Broglie-Bohm theory). URL_0 No wierdness involved. Many are still clinging to the wierd explanation required if using the Copenhagen interpretation because it is a more complete theory. I say, the simplest explanation is the most likely one. So the pilot wave explanation.", "It is a bug in the source code. The source code has clearly defined that any particle can behave as wave but since certain features are disabled when no one is there to watch (to save processing power) such as sound and exact location this leads to this strange behavior. When someone is observing the slits the need to display location overrides the hard coded wave-particle duality.\ufeff", "When a particle is emitted it is said to be coherent, it is basically a wave-like system that radiates out. The wave interferes with itself which is why we see the pattern. When you measure the particle, you affect the system, and you cause decoherence, that is when the system is not \"in sync\" with itself anymore. After decoherence the system takes a very long time to re sync itself. As to your questions there is a debates as to what exactly constitutes measurement. Clearly there are some things, like gravity, travelling through non-vacuum space, hitting the divider in the double slit experiment, etc. that do not seem to be enough to disrupt the system. What we do know so far is that doing something to the system that would localize a particle is enough to cause decoherence. Your last question is a little confusing, like i said above anything that can localize a particle is enough to cause decoherence. It's not about knowledge, it's about physical interaction, which i think you understand. Like i also said above, there are forces that impact the system, not capable of localizing the particle, that do not cause decoherence but still have sort of effect on the system.", "Via the Heisenberg uncertainty principle, you can\u2019t know the position and velocity of the electron at the same exact time. Think about taking a picture of a running man. The picture will blur the man, so an observer can tell that the man is moving and can infer his speed by the amount of blurring that took place. But, because of the blurring, we don\u2019t know his exact position. Now, have the camera be moving at the same speed as the man. The picture will not be blurry, and we can tell exactly where the man is, but we do not know anything about his speed. When the electron is moving toward the double slit, it is behaving as a plane wave, that is, it has a well defined wave length. This wavelength is proportional to its velocity via the principle of matter waves proposed by De Broglie. That means that the electron\u2019s velocity is well defined, so it is impossible to know anything about its position. The electron could be anywhere. This is what we call a delocalized wavepacket. There are a bunch of different possibility states the electron can occupy, and superimposing these forms a wavepacket. When single electrons head toward the double slit, they can appear to go through both somehow because they are occupying multiple possibility states. The act of measuring exactly which slit it\u2019s going through fundamentally changes the experiment because it collapses the electron delocalized wavepacket into a localized one. This causes the electron to occupy only one possibility state, and go through only one slit. This phenomena led to the Copenhagen interpretation, which stated that 1) quantum systems do not have definite properties before being measured 2) the act of measurement changes the system I hope this answers your question somewhat"], "text_urls": [[], ["https://www.youtube.com/watch?v=8ORLN_KwAgs"], [], [], [], [], [], ["https://www.youtube.com/watch?v=WIyTZDHuarQ"], [], [], []], "score": [441, 292, 263, 68, 28, 26, 21, 7, 5, 5, 3]}}, {"q_id": "97i8yg", "category": "Repost", "title": "How do people who crack games get said games to crack ?", "title_urls": {"url": []}, "selftext": "How do people who crack games get the games before they crack them? How do they get the source files on their pcs so they can crack them ?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["e48qj6s", "e48j2tu", "e48e5bw", "e48iaw5", "e48friv", "e48rnhm", "e48d9e3", "e48crlk", "e48g8rv", "e4919dx", "e499dkx", "e48w8fx", "e49jqtr", "e48g9qk", "e48pkxm", "e48naba"], "text": ["A man is reading a list of instructions on what to do. Let's say this particular list of instructions tells him how to let you into a theme park. As he goes through the list of instructions he asks you for your ticket, but you don't have one so you can't get in today. After his shift you know where he keeps his instruction list, but it's in German! And you don't speak German. But you take a copy anyway. Tomorrow you try to get in, and you follow the man along as he's reading the instructions, and when he gets to instruction 52, he asks you for a ticket, and then turns you away for not having one. After his shift, you go to where he keeps his instructions and cross out line 52. The next day you get into the theme park because he didn't check for your ticket.", "There's actually an awesome history of cracking groups. We won't go into it, but one of the most valued positions within a cracker group was often the person who could get access to games. In the early 2000s cracking groups would have people lift games from deliveries to their gamestop store. In fact, if you pirate on console you'll find those games are often out before the game itself. That's usually why. Someone works at gamestop and literally took a disc. For PC it gets more complicated. Whereas consoles tend to try and lock their console and leave their games unprotected, for PCs its often the other way around. And then you have Steam and online and blah blah. What PC games, especially on steam will do is either a) not ship the CD physically. The gamestop employee can just get the download code - not useful and very easy to trace that its been stolen. The game itself is often downloadable. or b) when they do have the files on the disc or predownloaded, they often are missing a key to unlock the files. This means day 0 on PC is pretty rare now. Not unheard of, FFXV was cracked before release because the demo exe had files they used, but for everything else it is often 3 months. So how do they get the games to crack em? Honestly? Probably just buy them and download them from steam. Then its something called reverse engineering. It used to be simple, there was a part of the exe file for a game that would check the cd was in the drive. All they'd need to do to crack it was remove the cd check. These were called no cd cracks! These are still invaluable for a lot of older games. Now though, you have something called Denuvo, and rather than simply putting in one line of code that can then get taken out, they add thousands if not millions of lines of code, woven into the code for the game. That makes untying all that and reverse engineering time consuming. Lots of people have hailed it as the end of piracy, and it has slowed it down. But it hasn't stopped. The problem with denuvo though is that its a lot of security through obfuscation - that is, it works as long as you hide how it works. This is great - until someone finds out how it works. Then literally all of your security becomes instantly useless. This has happened to Denuvo a few times. Each time it happens, its harder the next time to make your stuff secure. Because the crackers are onto you now. tl;dr - they used to have someone steal them, either from gamestop, or sometimes by someone within the developers. Less possible for this to happen on PC, but on console they still do it this way. Another way is the use of demo exes. Developers release a demo, and that demos exe contains the code that can be used to convince the program its legal.", "Indeed they don't have access to the source files. They have to work with the released binary EXE file as it is. To help crack they typically use a debugger application to step through the raw CPU instructions while the program is running, then editing the file once they find the exact location of DRM check. It could end up as simple as changing just a few bytes which correspond to a single jump instruction. Of course, things can get a lot more complicated with different types of DRM.", "ELI3: You get the program walking (like running, but slower, step by step) until you see it check if it's original. You follow him through all those steps until the check steps are over. You then make a bridge from right before the check to right after the check. The program can now run straight and never hit the check. Sometimes programs are designed to mislead you, walk in circles, do many checks in different parts, etc. That is what makes it difficult and challenging. --- Edit: Just to give a quick and simple perspective of how slow the program walk: If you have a somewhat common processor (running at let's say 2.5 GHz) that means that when running, a program is taking approx. 2,500,000,000 steps a second. Edit2: oopsie, missed 3 zeros.", "Back in the old days, we buy the game, crack open the cd casing and burn the disc into an ISO image for IRC XDCC file sharing. Today, we hex the exe files to figure out what the game does on launch and what to disable in order to bypass the \"disc/file detection\" portion. That is why you always get a modified exe file as the crack as said crack has the detection disabled, thus allowing for no-cd gameplay as well. The funny thing is back in the old days...even when we own the real game physically, we still download a no-cd crack for convenience lol. Ah the good old days. Mech Commander, anyone?", "They typically have a source where the DVDs are pressed or where the first copies are couriered. These people sometimes get paid money for early copies or access to group servers with free software as a reward for their services. Next the cracker had to figure out what type of copy protection is being used. If the game asks for a serial number it's fairly simple. You'll need a so called debugger which is a program that loads the file and executes line by line so that you can find the exact spot where the game asks for the serial. In that location will be a jump point to calculate if the serial you entered is valid. This part is an equation somewhere in the program like a + b = c just more complex. Once that equation is found you can make a key generator. This is a very simplified explanation. If the program needs a license like a physical file to be present it can be trickier. You can sometimes make the game think it's there by removing the parts that check for the file. Other times it's as simple as setting something from \"no\" to \"yes\". Then there's the situation where entire parts have to patched with additional code. There is no one size fits all solution, but the main steps remain: Identify protection Locate copy protection Remove/fix protection. There's debuggers that show the code as the program is executed, which tell you where to go in. Hex and other editors to modify the file. They use programs to freeze the game/software in order to locate jump points. And other programs to hide the cracking software being used as some games/software checks to see if certain prisms are running and just shuts down if it detects them.", "Often times they get the executables(binaries) directly from the CD/DVD or digital downloads. Then they will use a utility, like hexrays to attempt to decompile it, or reverse assemble. At that point they are looking for a way bypass the activation method or software security.", "The software is being cracked by reverse engineering already compiled product(game executable) and enabling the person to reach to some parts of the product which would enable him to change vital binary codings and override the protection. Not the simplest explanation, but i hope u get the idea.", "They often have sponsors or have the games gifted to them to crack them. They dont have the source code, but they decompile the installed files and pick through the memory of the running application to look for and disable the protection, then they write patchers to apply the changes to the executable.", "There almost HAS to be a patient zero nowadays for PC cracking. Most of the time it's someone who just legitimately buys the game and then distributes the game files. Unless there is an insider willing to dish out free copies to someone, which is also a method I've heard of. But that's risky. Sometimes it's by mistake, or through malicious efforts, such as compromising a studio and stealing the files. That's much more rare, but not unheard of.", "Back in the late 80's and into the 90's it was far easier. People who worked at software stores in the mall would simply take em home at night, make a copy (using just about any utility that could make an image of the disk) and then bring it back in the morning and reshrink wrap it. The reason was that there was no internet to validate things and serial numbers could easily be reused over and over again. In the 80's with Commodore games - it was even better - you'd just buy the game, use some software to copy and defeat the copy protection and then return the game. Since they didn't think you could copy games then and returning a game would just get re-shrunk wrapped - an opened game wasn't a problem like it is today. But of course I heard this all thru second hand conversations... :)", "Sometimes, they get leaked versions of the game from someone on the dev/testing team... maybe not directly, but indirectly they get access to early builds, or even retail ready versions pre DRM, or just early access to the normal version we all get. Also it should be noted that there are only a handful of DRM \"Types\", breaking it once will often make it very easy to break it again, and if you've already broken most of them out there, and new games release with the same old protections on them...sorry this isn't eli5 enouph... If a thief breaks into a vault, once inside he can clearly see all the weak points, and some vualts won't fix how he got in the first time, so he can just keep getting in until they come up with something new, at which point he either uses one of the other weak points, or starts over getting past the new thing.", "Post probably won\u2019t get read but from personal experience. Back in the AOL/CompuServe days, over 20+ years ago, groups were cracking and releasing software. A lot of the software came from the software developers or beta testers. Having a Microsoft beta tester access was a golden ticket to any online group, you would download the beta/final versions from a FTP server using your unique login and password. Other software had beta tester, ie: Starcraft and a lot of software were released that way. & nbsp; You then have the workers that work at the dvd/cd manufacturing warehouses. They provide a lot of the RTM/Golden Copy software releases or movie rips. Screeners/academy award/press/etc would get copies to watch before the official release and rip them. I still remember titanic was send to academy award reviewers with vhs and a classmate was using copies to score points with girls. & nbsp; Same with music, inside people who manufacture the CDs. Some of this involves triads/yakusa/etc once you go down the Asian manufactures. & nbsp; Production companies started to label each movies with special numbers to identify who leaked it, require special serial to unlock the software, movie screener played in color and randomly switch to black and white, cd required to run the software was adopted, dvd decryption code was adopted, serial numbers adopted, etc. & nbsp; Now cracking involved a lot of math to take multiple serial numbers and finding a pattern to create a serial generator. I still remember the calling for all the windows keys to help the group come up with a pattern and the key gen was created. Then online activation came and that was fun to crack. Hexing a file to look for certain codes like how the DVD movies was cracked because the software developer didn\u2019t encrypted encrypt the decyper key. It gets technical. & nbsp;", "Back in the day, and probably still happens, the gold disk would go to production in advance of the release. Workers at the production facility would steal a disk and post the binary files.", "I've cracked a program before, but the process is similar. Granted this is for super simple most likely older games. What you do is download a program like ollydbg and then watch a bunch of Youtube videos. The short of it is that you search the binary for any strings and then it gives you a list. You look for one that talks about the license not being valid. Then you open up where that is in the binary and look above it for a jump (jmp) and then try changing it to something else and see if that lets you skip the license check. If not, try another jump. Keep on going until you get the result you're looking for.", "Easy... By buying them :p It's like with scanlation... The scans don't just magic them self... Someone had to spend money on them... **OR**... They were leaked by a third party(review copy)/inside job/etc..."], "text_urls": [[], [], [], [], [], [], [], [], [], [], [], [], [], [], [], []], "score": [9458, 8367, 676, 377, 184, 68, 64, 37, 13, 12, 12, 9, 7, 6, 4, 3]}}, {"q_id": "9cfsej", "category": "Repost", "title": "The Great Filter", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["e5acruu"], "text": ["1. Statistically, the universe must be full of aliens 2. The universe is not full of aliens. 3. There must be something that all aliens face that stops them from taking over stars and galaxies. 4. We did not yet reach that something, but we inevitably will -OR- we already passed it, which is incredibly unlikely. That something is called the Great Filter."], "text_urls": [[]], "score": [4]}}, {"q_id": "9fn5ah", "category": "Repost", "title": "What is angular momentum?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["e5xqh2c", "e5xqgdi"], "text": ["Yarr! Yer not alone in askin', and kind strangers have explained: 1. [ELI5: What is angular momentum? ]( URL_0 ) ^(_4 comments_) 1. [Eli5, angular momentum ]( URL_1 ) ^(_4 comments_) 1. [ELI5: Angular Momentum ]( URL_6 ) ^(_5 comments_) 1. [ELI5: What exactly is angular momentum and how does it work? ]( URL_2 ) ^(_5 comments_) 1. [ELI5: The physical meaning of angular momentum and how it relates to angular velocity ]( URL_3 ) ^(_2 comments_) 1. [ELI5:The conservation of angular momentum ]( URL_5 ) ^(_4 comments_) 1. [ELI5 Angular Momentum and Velocity ]( URL_4 ) ^(_2 comments_)", "It's the term for when you spin a thing, it will keep on spinning unless other forces slow it down or stop it. For example, the Earth keeps spinning in space because it has angular momentum from when it formed and very few forces slowing it down."], "text_urls": [["https://np.reddit.com/r/explainlikeimfive/comments/1k3qc8/eli5_what_is_angular_momentum/", "https://np.reddit.com/r/explainlikeimfive/comments/16c0va/eli5_angular_momentum/", "https://np.reddit.com/r/explainlikeimfive/comments/1fcx23/eli5_what_exactly_is_angular_momentum_and_how/", "https://np.reddit.com/r/explainlikeimfive/comments/1xmooh/eli5_the_physical_meaning_of_angular_momentum_and/", "https://np.reddit.com/r/explainlikeimfive/comments/11c34s/eli5_angular_momentum_and_velocity/", "https://np.reddit.com/r/explainlikeimfive/comments/2y2udc/eli5the_conservation_of_angular_momentum/", "https://np.reddit.com/r/explainlikeimfive/comments/4kqqw2/eli5_angular_momentum/"], []], "score": [6, 3]}}, {"q_id": "9in38n", "category": "Repost", "title": "Why is it easier to balance (on a bike, unicycle, etc) moving as opposed to stationary?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["e6kwvhx"], "text": ["Momentum and inertia act against gravity to keep you upright when you are in motion. When sitting still you obviously don't have the benefit of motion to counteract gravity. URL_0 *\"Inertia, as defined by the second law of motion, is the tendency of an object in motion to remain in motion, and of an object at rest to remain at rest. Momentum, by definition, involves a body in motion, and can be defined as the tendency of a body in motion to continue moving at a constant velocity.\"* Of course, this is very complex topic on many levels since it's *literally* rocket science. But you count on these various laws of motion on a daily basis. A good example is throwing a baseball. If you hold the ball out and drop it, it falls to the ground. If you pull your arm back and throw it with force, it follows a vector through the air and temporarily counteracts the force of gravity. As the effect of the throw weakens, the ball falls to the group. If you throw it hard enough, theoretically, you can launch the baseball into orbit. These same laws of motion allow a bicycle to stay upright when force is applied to counteract gravity. Because you can continue to apply this force, you can stay upright for a long time counteracting the force of gravity by peddling. As soon you stop peddling, the force wanes and you eventually fall over like the baseball eventually hits the ground. With more input force the longer you can coast before gravity claims you."], "text_urls": [["http://www.scienceclarified.com/everyday/Real-Life-Chemistry-Vol-3-Physics-Vol-1/Momentum-How-it-works.html"]], "score": [4]}}, {"q_id": "abd8pd", "category": "Repost", "title": "Why are males not able to have multiple orgasms?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["eczh6m7"], "text": ["Because there is no evolutionary advantage of blowing your load then continuing to have sex thereby pulling sperm out of the vagina. This would decrease the likelihood of successful conception."], "text_urls": [[]], "score": [10]}}, {"q_id": "adc0ta", "category": "Repost", "title": "How do wireless chargers work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["edfld2i", "edflewj"], "text": ["Magnetic induction. Specifically, currents generate magnetic fields and changing magnetic flux generates currents. See faraday's law. This is also why the electric and magnetic fields are often combined into the electromagnetic field. And why light works. tl;dr is electricity make magnet, magnet make electricity So the wireless charger uses electricity to make a magnetic field. That magnetic field causes electricity to flow in your phone.", "Basically there\u2019s a coil of wire in your device and in the charger. Working on the same principle as a voltage transformer, a current is passed through the coil in the charger and the resulting electrical field generated by the wire, induced current into the other coil which generates a voltage that charges your phone."], "text_urls": [[], []], "score": [4, 3]}}, {"q_id": "adlpm1", "category": "Repost", "title": "Why did the US Never get on board with the rest of the world with the metric system?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["edi494g", "edid0l1", "edil6da", "edi4rvi", "edi5vcn"], "text": ["They tried. The Metric Conversion Act was signed in December of 1975, but the only issue was, it was voluntary. It was never really enforced, and it only stated that metric was the preferred way to do stuff. With no pressure to switch, nobody switched", "The US is completely on board, where it makes financial sense. Schools teach all students the metric system. Science is almost exclusively metric, and most of engineering is capable of being metric. You can buy metric tools and fasteners in the local hardware store. The only thing that isn't metric, cooking and roadways, would simply cost too much to change for the benefit metrication would bring.", "They mostly didn't have a choice. Metrication was a big push during the French Revolution, and spread through Europe during the Napoleonic Wars by ramming it down the throat of the conquered nations. The US was already independent before the first of those, and was not subject to the second. European countries went on to conquer most of the world, leaving them with those measurements in the post-colonial era, but it never took hold here, especially because the Industrial Revolution made switching expensive - you would have to re-tool all your assembly lines. It's like how Canadian French is very, very different from metropolitan/continental French: it was the local dialect of a small group of settlers, and they kept on talking the same way, while the mother country mostly adapted to the Parisian dialect, at least in formal speech/writing. In science, engineering, and medicine, nobody uses Imperial units. Fahrenheit is a somewhat special case; I'm unconvinced that it's inferior to Celsius for practical purposes, though there is a good point to be made that it would be better if we all used the same scale. For science, you should be measuring in Kelvin (or Rankine, if you prefer Fahrenheit's degree spacing).", "The US has been involved with the metric system since the start. All the US measurements are actually based on SI standards, so a yard isn't 36 inches, and a pound isn't 16 ounces - rather 1 yard = 0.9144 meter and a avoirdupois pound = 0.45359237 kilogram", "Money, think about re standardizing things and the cost to inform the public, reprinting books, re training labour ect ect"], "text_urls": [[], [], [], [], []], "score": [26, 10, 5, 4, 3]}}, {"q_id": "afpzoz", "category": "Repost", "title": "How come when you really have to pee you can be relatively okay until you step through the threshold of your home and it becomes a desperate race to get your shoes off and pants unbuttoned before you pee your pants?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ee0lmif", "ee0oh46", "ee0oqc2", "ee1042q"], "text": ["It's like a weird type of Pavlavs response. Your body knows it can relieve itself in the bathroom and the closer you get the more the subconscious response to empty your bladder becomes noticable.", "( I know many people have strict policies of no shoes in the house but it's hilarious to me thinking about having to take your shoes off to pee", "Unbuttoning your trousers I understand, but why would you need to get your shoes off when you're going to the toilet?", "When I was a kid I walked to school every day. Some days, as soon as I put the key in the door after my walk home from school (about one mile) I would have to go so badly, I was worried I wouldn\u2019t make it to the bathroom in time. We lived in a house built at the turn of the century and one day I couldn\u2019t get the wonky door to unlock and thought I was going to burst so I peed in the backyard. I don\u2019t think I\u2019ve ever told anyone I did that."], "text_urls": [[], [], [], []], "score": [99, 48, 14, 12]}}, {"q_id": "agw3wh", "category": "Repost", "title": "How come full scale quad copters as big as helicopters haven\u2019t been developed, considering the drone versions seem to be much more stable than the single rotor helicopter RC drones?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ee9hcjc", "ee9ozpx", "ee9h9mm", "ee9yd5h", "ee9h0iv", "ee9pu14", "ee9isi2", "ee9sx1r", "ee9lq0z", "ee9q09n", "ee9ic1p", "ee9p6jx", "ee9utej", "eeao43l", "ee9nhrk", "eeabx3f", "eea9oi8", "ee9v6j7", "eec3zpp", "ee9th7p", "eeaw9q4"], "text": ["The biggest quadcopters are comparable in size to the smallest manned helicopters. A quadcopter is based on very different principles of control and stability from other helicopters. Ordinary helicopters have a set of rotors linked together to balance the forces and then change the pitch of the rotor blades for control. This is a mechanically balanced system as any variable unknowns like the rotor speed have an equal effect on all components. However a quadcopter is a mechanically unstable system that requires constant corrections by the electronics in order to stay balanced. This means that you need motors that have a very fixed speed and can change speed very fast. So quadcopters need special electric motors. You can not build a quadcopter out of any electric motor or out of a combustion engine because these can not be controlled in the same way. This creates some issues when you attempt to scale the design. If you look at bigger quadcopters you will notice that they usually have more rotors then the four classical rotors. This helps with the scale although you can not just mount a hundred motors on a helicopter without issues.", "From the RC perspective, the single rotor RC helicopters came before the advanced sensors required to automatically stabilize and hold position. Once the technology came, there was no motivation to add it since the main purpose of those helicopters was to be [deliberately unstable for 3D helicopter flight]( URL_0 ). Multirotor drones by design requires the use of sensors just to be able to be flown by humans. The early ones were just as unstable as single-rotor RC helicopters and required constant input from the human controller in order to remain stable. Then, since the sensor technology was already there, people added automatic leveling, where if you let go of the controls the heli would automatically orient itself. The next step after that was to add GPS functionality, so the heli would be able to automatically correct slight drifting and remain in a single place. Basically multirotor RC helis had most of the tech needed for the automatic stabilization anyways, while traditional RC helis didn't and were primarily intended to do unstable 3D flying anyways.", "Short version, human sized quad-copters or quad helicopters: more rotors = more engines, higher fuel consumption, more difficult design, more construction materials required, higher overall mass that does not necessarily translate into being able to lift more, bigger then regular designs, many more parts to maintain, more overall costs and an overall greater risk of failures and risk of the whole machine failing and crashing as a result, as it only takes 1 out of 4 engines/rotors/load bearing arms to malfunction to send it crashing down. (You could compensate for the loss of 1 engine/rotor/arm, but only so much...), then there's also the issue with auto-rotation being non existent on a quad-copter amongst other more complex topics.", "The short answer is efficiency. The best way to make an example of this, is to use model helicopters. (becuase they're the best apples to apples we can do..) The common size quadcopter is a 250mm quad. That's roughly the same size as a 130 class helicopter. Your typical 250mm quad has a \"few minute\" flight time. On a very large battery. Lets be nice, and we'll call it 5 minutes on a 25 watt hour battery. A 130 size helicopter will fly 7 minutes, on a 2.2 watt hour battery. So why is that? All powered lift aircraft need to grab big chunks of air, and throw them at the ground. Getting a good grip on the air, is really controlled by how big of a wing (rotor, prop, whatever..) you have. The most efficient part of a wing is the part furthest from the tip, and moving the fastest. Helicopters get this right, by having long blades, and few rotor tips. Multirotors get it wrong, by having LOTS of tips, and short blades. I\"m making a very strong case, against multirotors. And for carrying people, large loads, and doing many tasks, they are really awful. And when you start building a multirotor to carry heavy loads, fly long ranges, or have good flight times, they start looking a lot like normal helicotpers. EG: a popular thing with the quad community is to build \"long range\" rigs. Instead of the typical 4.5 or 5\" props, they're swinging 7\" props, more than doubling their effective swept area. Helicopters, are also \"human controllable\". That is, a meatbag at the controlls can fly it well. To fly a multirotor, you need computers doing the work for you. Multirotors also can't autorotate. \"Real\" Helicopters can become a glider, and land safely in the case of an engine out situation. Multirotors, if you unplug the battery, crash.", "The V-22 Osprey is a twin copter, and it was plagued by issues during its first few years of active use. I think the struggles experienced by this vehicle has slowed the development of a full-scale quad copter. Additionally, quad copter drones can be made with lightweight plastic material, where a full-size version could potentially require an unattainable weight/lift ratio.", "[ URL_0 ]( URL_0 ) it was shown at CES 2019", "Drones work because they use fixed pitch propeller blades attached to electronic motors that speed up or slow down independently to create lift. full sized rotor craft use collective pitch for control. Meaning that the main rotor rotation speed stays(relatively) about the same speed and the angle of the blades goes up or down. Drones are light and only fly for short amounts of time. Around 20 minutes. This makes them perfect for electric power and and electric motors. A full sized aircraft engine just cannot change engine speed as fast as an electric motor. We also don't have electric motors that have developed advanced enough to be feasible in regular full scale flight. Now you're thinking \"Well why not do the collective pitch like helicopters?\" Well you're right, the V22, uses this option and it's very complicated. And has had lots of problem through development and deployment. Imagine multiplying it and having 4 or 8 collective pitch rotors that all need to come together to one central control area. It's needlessly complicated and very prone to failure. As of now there is no reason to put lives at risk for an overly complex contraption like that.", "There are a number of reasons quadcopters (and multicopters in general) haven't been used at full scale, but I'll highlight some important ones. * First, rotors get more efficient the less weight they have to carry. Making a single, big rotor uses the most space for a given box. If your aircraft has to fit in a 50' wide box, a single rotor will give you the best efficiency. You could overlap multiple rotors, but that tends to make them shake themselves to pieces unless they're on the same shaft. * Second, rotors are hard to hold on to. Try hanging from a tree branch. Now, try hanging from two tree branches with your arms horizontal. The arms to support a quadcopter can be much heavier than the single connection to a main rotor. * Third, sending power from your engine to the rotors is hard. Doing it for a quadcopter is complicated for an engine, so we usually use electric motors. Wires are simpler. That requires powerful, **lightweight** aerospace-grade electric motors which literally don't exist. Siemens is working on some, so is (was?) ThinGap. We're just starting to get ones big enough for manned multicopters. * Fourth, safety. When a helicopter loses power, it can perform an \"autorotation\" to effectively parachute to the ground. This is much easier to do with a single, large rotor than multiple small ones. Quadcopters trying to autorotate hit the ground too fast and go splat. This is why the Bell Nexus multirotor transport concept uses 6 rotors. A quadcopter can't fly on 3 motors. A hexacopter can fly safely to the ground on 5. As it turns out, there are a number of other, more technical reasons, too (though rpm vs pitch control is not one of them), but these four are enough. The third reason being close to solved is a big part of why lots of designs are popping up. I would *never* step foot in an ehang.", "Larger propellers use less energy for thrust. If two small propellers create the same amount of thrust as a single large one, the large one will be using less energy. As you scale it up, the logical conclusion is to use one big propeller to create all the thrust.", "URL_0 Workhorse is working on an 8 rotor (4 sets of inline rotors) helicopter. I've been following this for a while, it looks like they've reached manned testing.", "Quads rely on very rapid changes in motor rpm to control the aircraft. This is accomplished with electric motors. No other type of propulsion can reach as quickly. As a result, quadcopters use batteries and are thus limited in flight time. A 30ish minute flight is about all you can expect of batteries before you have to land and change them. If more or bigger batteries were used to try and extend the flight time, the weight of the aircraft becomes prohibitive. This works fine for the type of work being done by most drones but is not ideal for manned flight. If a way could be found to provide enough electricity for much longer flights and the \"refueling\" issue addressed, or a propulsion system that could rival the response time of electric motors but does not rely on electricity could be developed, then you'd probably see a surge in manned quadcopters or higher (octocopters, etc). More motors means redundancy and more safety.", "Geometry does not favor medium-large quadcopters in certain ways. The things that people are saying about the complications and control issues are all quite correct, but all those things can be overcome with technology. But four rotors of equal \"surface area\" of one large rotor are going to have to have a bigger overall footprint than one large rotor. And the body of the copter will have to be equally widened, to accommodate four axes. So given the control problems and the geometry problems, single rotor helicopters will probably always be better UP TO THE LIMIT THAT A SINGLE ROTOR CAN SUPPORT. We've long since reached the size and speed limits of single rotor helicopters, because single rotors have their own geometry problems, mostly concerning the rotor speed versus the speed of sound. So the focus on quadcopters will probably be making normal sized ones as technology test beds, then jumping immediately to these crazy enormous monsters that dwarf single rotor stuff in size and lift capacity.", "Two reasons: 1. They aren't actually more stable 2. Cost and efficiency Without going into the physics in detail because ELI5, quadcopters aren't actually more inherently stable. They just have advantages for very small platforms and electric motors. It really all comes down to how wings work - remember, a rotor is nothing more than a rapidly-moving wing. As a wing gets bigger, the lift it produces increases with its *area*, but its weight increases with *volume*. That means weight is growing at a power of three while lift is growing at a power of two. So tiny wings have much more lift for their weight, and don't have to rely on expensive composites. As a result, they can use simple but heavy over-the-counter batteries instead of the explosive hydrocarbon fuels full-size aircraft require. This makes small aircraft much cheaper and simpler to make and operate. As a result, in a handheld quadcopter, each rotor can be powered by its own simple electric motor, which in turn is powered by batteries. To do the same thing for a manned quadcopter, you'd need four internal combustion engines, with all of the weight and fuel that translates into. Obviously, no one is going to do that, so instead, you'd have one or two engines, with a hideously complex transmission to power all the rotors. Or...you could just use the current system.", "For Quadcoptors to fly correctly, they need instant torque, which can only be provided by special electric engines. These use batteries, which are a lot less energy-dense than gasoline. A traditional helicoptor has the much more efficient fuel, but a combustion engine is incapable of providing instant torque and starting/stopping. So in other words, if we had much better/efficient batteries, then we would have full size quad coptors.", "[ URL_0 ]( URL_0 ) & #x200B; [ URL_1 ]( URL_1 ) & #x200B; People are experimenting, it will be done one day you can now, if you want to tinker and take on some personal risk & #x200B;", "[ URL_0 ]( URL_0 ) hows Uber doin it?", "They do have one. It was revieled at ces 2019. URL_0 Dang u automod this answers the question!", "[Oh you mean like this one, being shown this week at the North American International Auto Show?]( URL_0 )", "One of the biggest problems with scaling is due to what's known as the square-cube law. Basically what this says is that as you scale up, some properties, such as weight, increase with the cube of the scale factor. Others, such as area, scale with the square of the area. The amount of power required to lift a vehicle is proportional to the weight^1.5 / rotorArea^0.5. As you scale up a given design by scale factor \"s\", the weight increases by s^3 and the rotor area increases by s^2. This means that the power increases by (s^3 )^1.5 / (s^2 )^0.5 = s^3.5. Since 3.5 is greater than 3, what this tells us is that the power increases more quickly than the weight increases. As a result, since the amount of fuel stored onboard also scales with volume (or s^3 ), as you scale up, your fuel will last less and less time. Bigger - > much heavier - > even more power - > less time flying", "First you need to know the differences in the designs between quad copters and helicopters. Helicopters are designed to have a constant rotor speed, and change the pitch of their rotor blades in different ways to control the way the helicopter flies. In quad copters, the pitch of the blades is fixed, so the only way to control the quadcopter is by varying the speed of the blades. Varying rotor speed is pretty easy on small quad copters but as it scales up, it becomes more difficult due to the weight of batteries, or if you\u2019re using jet engines, due to the time it takes for the engines to spool up. There\u2019s also the matter of safety. In a helicopter, of the engine quits, a helicopter can autorotate. In a quad copter, if one of the four motors quits, you essentially have to shut down the opposite motor to maintain any semblance of control, and I could be wrong on this point, but I\u2019m fairly certain there\u2019s no way a conventional quad copter would be stable only running two motors. A quad copter could be designed with some sort of variable transmission that drives all four rotors from a single or multiple engines, but you end up with the same concerns... what if the drive shaft fails? And with this design style, the usable load of a quad copter would be minuscule.", "Most of the answers here so far touch on the issue but don't correctly answer the question. Firstly the advantage of quadcopter is that they actually are less stable but more maneuverable than single rotor helicopters so the question is a little misguided. Basically the more rotors you have the more independent control you can have and the more maneuverable you can be. The reason quadcopter seam more stable is that they have electronic stability control while single rotor helicopters tend to be stable enough to be controlled directly by humans without needing electronic stability augmentation but if they were equipped with similar system they could be just as stable. Secondly the primary reason why larger rotorcraft have fewer but bigger rotors is related to efficiency above all else. In smaller quadcopter the maneuverability is a worthwhile tradeoff for reduced efficiency and range but in larger vehicles speed and range are much more important than maneuverability. Think of it like this, if I gave you an hour to empty a bathtub filled with water and the choice between using a shovel and spoon you would of course choose the shovel over the spoon. Similarly the bigger a rotor blade is the more air you can move at a time and the more efficient you will be. Last but not least if you did choose to build a large multi rotor, while they would look reasonably similar they would have to work fundamentally differently from small quadcopters. Small quadcopter depend on being able to rapidly change the speed their rotors spin for control. The bigger the rotors are the more powerful the engine has to be in comparison to the vehicle to achieve similar speed changes as the quadcopter does with its small blades. Eventually the engines required would become so big and heavy that that most of the vehicle would have to be engine. As a result you would need to change the control system to be more similar to how a single rotor helicopter works with constant rotor speeds that you can steer. This would make the rotors far more complex than the simple ones on quadcopters eliminating this advantage of simplicity that they would have. & #x200B; There are some other things like for example efficiency of scale when it comes to engines that favor fewer larger engines rather than many smaller engines but these are the main ones. TL;DR 1. helicopters are more stable but less maneuverable than quadcopters actually 2. single large rotors are more efficient than many small rotors. 3. if you did it they would be more like four bladed chinooks than quadcopters. & #x200B;"], "text_urls": [[], ["https://www.youtube.com/watch?v=PptMrBFAO-A"], [], [], [], ["https://www.bellflight.com/company/innovation/nexus"], [], [], [], ["http://sureflyaero.com/"], [], [], [], [], ["https://www.youtube.com/watch?v=L75ESD9PBOw", "https://www.youtube.com/watch?v=pI2j4KEPQI4"], ["https://www.youtube.com/embed/WpQVDiRiFfg?start=31"], ["https://www.gpsworld.com/bell-helicopter-unveils-full-scale-air-taxi-at-ces-2019/"], ["https://twitter.com/NAIASDetroit/status/1085596069097025536"], [], [], []], "score": [8158, 300, 167, 138, 82, 57, 41, 33, 18, 12, 12, 7, 7, 5, 4, 3, 3, 3, 3, 3, 3]}}, {"q_id": "aia6qn", "category": "Repost", "title": "How de we sent pictures all the way from other planets without losing any data and still get the full picture?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["eem6p7s"], "text": ["For one, the devices in question are using a dedicated high strength signal/channel, not a shared network like the internet or your cell phone. But more importantly, they also don;t send just one copy of the data in question. They send multiple copies along with parity data so that anything that might be lost in transit can be rebuilt from another copy or the parity data"], "text_urls": [[]], "score": [6]}}, {"q_id": "altgib", "category": "Repost", "title": "How do you programm a computer without a computer? (e.g. first computer)", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["efgu4ym"], "text": ["The first computers were operated with switches. Those switches were manually flipped to indicate the input into the computer. Later on there were things like memory which allowed a set of switches to be set, a button pressed to enter them into a \"register\" or set of memory values, then the switches flipped to another set of values and entered into a different memory register. That quickly became tedious so later innovations included easier ways to enter binary values such as punch cards where holes or lack of holes indicated binary digits, and strips of tape with holes similarly indicating binary settings."], "text_urls": [[]], "score": [4]}}, {"q_id": "dtpi6u", "category": "Repost", "title": "Why do some human hairs stop growing at a certain length but others seem to grow indefinitely?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["f6y2mb2", "f6y6ccv", "f6yp98r", "f6yumh2", "f6yu4mq", "f6ys8na", "f6yaymx", "f6yy2xr"], "text": ["Not all hairs are created equally. Most have a maximum length they can achieve before regular wear-and-tear causes them to fall off. Arm hairs will stop growing after a couple of months, whereas the hair on the head grows for a few years before it stops. Hair growth occurs in phases. The first phase is called the *anagen* phase, and it's the only time that hair actively grows. How long your own anagen phase is will be dependent on your genes. This is why some people just can't grow beards, or can't ever seem to get their hair as long as they want it to be. The typical anagen phase for a healthy adult for head-hair is between 2 and 6 years, long enough to grow around 1 to 3 feet. The typical anagen phase for arm hair is between 3 and 8 weeks, maxing it out at one or two inches. Once the anagen phase is over, it enters into the *catagen* phase. All the growing is done, but you might actually gain a little bit of length hear as the follicle pushes the hair out before it begins to grow another strand of hair. After catagen comes *telogen*, the resting phase, where the follicle sits dormant for a while (up to several months). This is when the old, dead hair falls off/gets pushed out. After that, it goes back to the anagen phase. And thankfully, all of this is staggered all over our (human) bodies. At any given moment, some of our hair is in any one of the three phases. Whereas for animals like long-furred dogs or sheep, it all happens at at the same time in the form of summer/winter shedding.", "Your hair grows in cycles. The max length of the hair on any specific part of your body basically tells you how long the growing cycle is for those hair follicles. When the cycle is over, the hair will fall out. Every follicle has its own cycle, they are not in sync with each other, so you don't notice that they are all falling out eventually. For example arms and legs have a very short cycle while your head has a very long cycle, and then there's everything in between like that one random long hair that you find on your ear.", "When I\u2019m stressed I pull out beard and eyebrow hairs...to the point that there are bald patches...goes in phases and SEEMS to always come back Will I ever kill the hair follicle or whatever?", "The top comment is a great answer. I just wanted to add that your body has different types of hair. Indeterminate and determinate. Indeterminate is the hair on your head. It can keep growing as long as it's in the right phase. Determinate hair is the hair everything else. Your genes tell it what length it should be and when to stop. For example your eyebrows are determinate so they don't get so long to cover your eyes.", "My husband has an 11cm long back hair - just one and it's grey. The rest of his back is relatively hairless. If it is pulled out it just grows back again over time. We have no idea why the alpha hair grows so much longer than the rest.", "I felt trigggered. My under arm hair is like singing \"grow, grow, grow\" and here I am shouting \"STOP, STOP, STOP!!!!\"", "They don\u2019t stop growing, the follicles have a loose hold on the hair so they release the hair after a time and start over....so they\u2019re constantly falling out. They\u2019re called guard hairs.", "How does the hair know it's been cut? It grows from the follicle not from the end.. and it's built out of fibers and such so how would they even deliver the message to the base of the hair? Like grow more I have been cut? Also if it's by weight or something wouldn't putting your hair in a ponytail confused the process?"], "text_urls": [[], [], [], [], [], [], [], []], "score": [6113, 140, 48, 18, 11, 8, 7, 5]}}, {"q_id": "ebaegl", "category": "Repost", "title": "Why aren't illegal activities recorded in documentaries/youtube videos/any media prosecuted?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["fb3gfzl", "fb3uh3c", "fb3sxwj", "fb48xm8", "fb461sg", "fb46hy0", "fb44so0", "fb3s0dh", "fb4dzu6", "fb4e7kg", "fb47ws2"], "text": ["Science and reporting have an interesting relationship with lawbreaking and the law. Generally, scientists and filmmakers have to promise to keep secret the information of criminals that they record. In return, the criminals allow them to study and observe their practice. Meanwhile, law enforcement recognizes the fact that if they crack down on these criminals now, then they will refuse to cooperate with scientists and journalists in the future, which means police have less information to go off of. There was a high-profile case where this trust was violated and scientists were forced to surrender data on terrorists who had participated in a research study to the U.S. government. It is theorized that this event has seriously hindered our research of terrorism ever since.", "I have irrefutable proof on film that Arnold Schwarzenegger is a mass murdering robot from the future. Why haven't the police arrested him? Admitting something to a reporter is rarely, by itself, suitable grounds for prosecution. All your lawyer has to say is \"he was lying because he wanted to be on TV\".", "> How is this not seen by police who then take action, knowing the man's name? In order to be convicted of a crime the prosecutor has to prove that there was a discrete violation of the law. This means that they need to be able to point to a specific act that occurred. A generalized \"I break the law\" isn't good enough. That being said, if someone admits that they are *currently* breaking the law, that admission can be used as probable cause to get a search warrant. The search warrant can then be used to prove the specific act. But I think a lot of people don't really understand the point of most crimes. Most minor crimes, like drug crimes, don't exist because the government cares about stopping them, rather, they give the police a pretext to get people who are committing more serious crimes off the streets. If you've ever been the victim of a break in, robbery, or assault what probably happened was that you reported the crime to the police and were told \"don't expect this to ever be solved.\" The reason that crimes like that don't get solved is that to convict someone of a crime like that you generally need a witness who recognizes the perpetrator and who is also willing to testify in court. Finding a witness who recognized the perpetrator is hard enough. On the off chance that you do find one, getting them to testify is borderline impossible. This isn't a snitches get stitches thing, but rather stems from the fact that its costly to testify. Doing so requires you to take at least one full day off work, possibly more if you get deposed before trial. Then you need to drive downtown and pay for a full day of parking. All for something that probably doesn't affect you in any way, shape, or form. What this means is that very few crimes are actually solvable, but that doesn't mean the police don't know who is committing them. The police actually have a pretty good idea of who the criminals in the community are, they just can't *prove* it. What they can do is follow them around and pull over their car for a minor traffic offense. As it turns out, the people who are committing more serious crimes tend to be committing those crimes to pay for a drug habit, which means that they're usually carrying drugs around. And those drugs generally get discovered during a traffic stop. That drug find allows the police to get those people off the streets. Maybe not for as long as they would go to jail if convicted of the other stuff they were doing, but its better than nothing. If they're on probation drugs are an even more powerful vehicle for putting them in jail because if you're on probation the police can search your house whenever they want. So if the police hear that someone on probation is breaking into cars, or whatever, then getting them off the street is generally just a matter of sending their probation officer to search their house. Cockfighting is a bit different in that it its more of a public nuisance than drug use is, but again its a pretextual crime. The police don't really care about cockfighting, but its an obnoxious activity that neighbors will frequently report. And, more importantly, the people engaging in cockfighting are typically also engaged in other crimes. But how does this all affect people who admit to crimes on TV? If you're someone who is known to the police and you admit to be actively involved in a criminal activity you can expect that the police will use that to get a search warrant. But if you're just \"some dude\" then nobody cares. The police aren't generally in the business of going out and rounding up everyone they see rolling a joint on TV.", "\"Because the prosecutors allow it.\" ELI35: Here's a great example: David Gregory, an NBC host, was having a segment on his show after the Sandy Hook shooting. During the show, on national TV, broadcast from Washington D.C., he [held up a 30-round magazine]( URL_0 ) that a staffer had bought earlier that day. Now, that's specifically illegal, as referenced by the Attorney General of DC's office: > It is unlawful under D.C. Code Section 7-2506.01(b) for any person while in the District of Columbia to \u201cpossess, sell, or transfer any large capacity ammunition feeding device regardless of whether the device is attached to a firearm\u201d or loaded. Nevertheless, when it came time to actually charge him with possession of a highly illegal and regulated device: > OAG has determined to exercise its prosecutorial discretion to decline to bring criminal charges against Mr. Gregory, who has no criminal record, or any other NBC employee based on the events associated with the December 23, 2012 broadcast. OAG has made this determination, despite the clarity of the violation of this important law, because under all of the circumstances here a prosecution would not promote public safety in the District of Columbia nor serve the best interests of the people of the District to whom this office owes its trust. So that's what it is. Even though he's committed a clearly illegal fact, on tape, with zero defense, he's not charged with a crime due to prosecutorial discretion. Which, honestly, is usually a good thing. There are plenty of reasons *not* to charge someone with a crime. Law is black and white, but lots of crimes are more of a gray area. And, in this example, it's probably a *good* thing that a reporter didn't get sent to jail or prison for this incident. It does nobody any good.", "Well, that 19 year old that filmed herself throwing a chair off her condo balcony was certainly charged by Toronto police over the incident.", "I once saw a video on people making an actual gun (illegally) like 5 years ago. then I saw one of some guys actually making coke (the drug... ) with those bright lamps and stuff. I didn't know why the film makers didn't call the police, but apparently the film makers have to make a promise saying they won't call the police, or something along those lines. and that makes them trusted, so they could film other similar things using that trust", "Because the police/prosecutors didnt do the work to properly charge you. A lot of the suspects on Datelines \"To Catch A Predator\" were never charged as the courts saw it as the show was doing all the work, and entrapping people. The cops were there simply to slap cuffs on anyone that came by. That's not doing the job correctly, and violating people's rights.", "Never ceases to amaze me how media can find anyone, interview them etc yet cops spend years following", "Well, if the illegal activities happen where I live (North Minneapolis) there is a super simple answer to this question. These illegal activities are not prosecuted because the police are worthless. In North Minneapolis, I was in a minor car accident. Someone rear ended me. They driver let me take a photo of himself, his license, and his car, then he just drove off before police got there. When police finally arrived, I gave them all the photos. They said the driver was driving on a suspended license, in a car that was registered to someone else, and they won't be doing anything about it because \"they didn't see it happen.\" Sorry, I am a little salty about law enforcement not enforcing laws.", "It's also worth pointing out that its never going to be a person in charge who accepts to be on the video, its always low level people doing low level shit that agree to be in these videos. You never get reporters going with a hitman to show them how he does it, or talking to a mafia boss showing you how he runs things, and torturing people. You do however get people willing to talk about how they sell meth or run a dog fighting ring. Gordon ramsey did that thing on cocaine which is a good example of what i mean. In that program we got a talk with a dude in the jungle who mashes up the leaves \\[and how he does it which is common knowledge anyways\\], some stuff with the police and a chat with some alleged sicarios with masks on, but all they did was stand there holding some 9mm's, trying to look hard. You also get a lot of criminals willing to talk about their crimes after serving their punishment, or folks willing to talk about it after they left the life and stuff. But its all just hearsay unless it can be proven.", "Sometimes it's across portraying the events, because of this, it's hard to prove of something is acting or not. An assault case (woman slapped another woman) was thrown out because it happened on camera and there was no proof that this wasn't scripted for the particular TV show."], "text_urls": [[], [], [], ["https://www.washingtonpost.com/video/thefold/david-gregorys-high-capacity-magazine/2012/12/26/5b590a72-4faf-11e2-8b49-64675006147f_video.html"], [], [], [], [], [], [], []], "score": [2340, 365, 107, 75, 45, 19, 17, 15, 7, 5, 3]}}, {"q_id": "amqxrk", "category": "Repost", "title": "How do the sensor bars at the entrances and exits of shops work?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["efnwi3f"], "text": ["It emmits a laser beam (usually IR) that reflects of the surrounding structure, the sensor picks up the reflection (the echo so to say) if something enters the area the echo changes and the sensor realises it and opens the door"], "text_urls": [[]], "score": [6]}}, {"q_id": "apw1gq", "category": "Repost", "title": "why does it seem like cars move in packs?", "title_urls": {"url": []}, "selftext": "I can understand that stop lights can create groups of cars, but I\u2019ve noticed this phenomenon even on highways where you\u2019d think cars would spread out evenly. However, it still seems like groups of cars form.", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["egbjh0u", "egbjhld", "egbjf6o", "egbnt96", "egbjftk"], "text": ["Slowness Waves. It turns out that it only takes one slow car to generate a traffic pack. They effect even cars in the adjacent lanes, because people don't like to go too fast past another car. Even if the slow car speeds up, the slowness wave (or sometimes called a [Traffic Snake]( URL_0 )) remains, moving slowly in the opposite direction to the cars.", "Consider a bunch of cars driving along a road with almost the same speed, some slightly faster and some slightly slower. The faster cars will tend to approach the slower cars from the rear but, being only slightly faster, not choose to speed up to pass but rather slightly slow to match speed. Repeat a few times and you have a clump.", "its a phenomenon caused by, as you said, stop lights and stuff. also something as simple as 1 person hitting their brakes. the person behind them hits their brakes, and the person behind them hits their brakes.. etc etc. this is why traffic jams happen and can last for hours. other reasons are stuff like during heavy storms you tend to see people sticking together.. theres 1 person in the front with a good truck that isnt really intimidated by the elements, and a bunch of people kinda following behind them in a group so they can feel more comfortable on the road. also i think a lot of people like to just \"go with traffic\" to follow (or not follow) the speed limit.. this leads to people sticking together. i dono, i can tell you that there are entire fields of jobs that study this stuff though. where i went to college, traffic engineering was a degree that you could get. it was a bunch of smart asian kids", "People who want to go 70mph tend to get stuck behind people who want to go 60mph, and form a big clump.", "[This previous post]( URL_0 ) has over 1800 comments."], "text_urls": [["https://www.youtube.com/watch?v=iHzzSao6ypE"], [], [], [], ["https://www.reddit.com/r/explainlikeimfive/comments/8dfqns/eli5_why_do_cars_travel_in_packs_on_the_highway/"]], "score": [10, 7, 6, 5, 3]}}, {"q_id": "b85vrx", "category": "Repost", "title": "Do our brains have infinite storage for memories of will we run out of room eventually?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ejw0lw1"], "text": ["Great minds think alike. I've sailed far and returned ta port with this booty. Yer not alone in askin', and kind strangers have explained: 1. [ELI5: Does the human brain have a capacity limit? Is there a limit to the amount of knowledge, memory, and data a single human brain can contain? ]( URL_5 ) ^(_28 comments_) 1. [ELI5:What is the limit of our brain? ]( URL_4 ) ^(_4 comments_) 1. [ELI5: How do we remember everything? Doesn't our brain get overloaded with information? ]( URL_2 ) ^(_13 comments_) 1. [Is there a limit to how much information a human brain can hold? ]( URL_1 ) ^(_2 comments_) 1. [ELI5:Can our brains run out of memory? ]( URL_0 ) ^(_._) 1. [ELI5:How are memories stored in the human brain? Is there a theoretical limit to the amount of information that can be stored? ]( URL_3 ) ^(_8 comments_)"], "text_urls": [["https://np.reddit.com/r/explainlikeimfive/comments/2kq7wk/eli5can_our_brains_run_out_of_memory/", "https://www.reddit.com/r/NoStupidQuestions/comments/aueyn7/is_there_a_limit_to_how_much_information_a_human/", "https://np.reddit.com/r/explainlikeimfive/comments/5ut0ux/eli5_how_do_we_remember_everything_doesnt_our/", "https://np.reddit.com/r/explainlikeimfive/comments/1f3bg8/eli5how_are_memories_stored_in_the_human_brain_is/", "https://np.reddit.com/r/explainlikeimfive/comments/5x3pj3/eli5what_is_the_limit_of_our_brain/", "https://np.reddit.com/r/explainlikeimfive/comments/3hjz0h/eli5_does_the_human_brain_have_a_capacity_limit/"]], "score": [7]}}, {"q_id": "bawhab", "category": "Repost", "title": "Why do soap operas have a certain look, different from other TV shows?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ekeh0qz", "ekehxog"], "text": ["Two main reasons. The first is that they use high quality cameras and high frame rates (~60) while the norm in film is about 24. Not everyone likes the difference because while the higher frame rate is technically better it reminds people of the second factor, which is... The scenes are shot with even lighting from all sides. In movies there is a lot of care taken in setting up lighting for every shot. A character might get a main highlight from one angle and then a softer, dimmer fill light to show what would otherwise be in shadow. Also a light would be placed behind them to accentuate the edges of their form. When they change positions the lighting along their path needs to be designed in a similar way and that means the actors need to be careful that they move precisely where and when they are supposed to, and there is a bunch of work and time setting up and breaking down the lighting between scenes. Quickly produced soap operas don't have time or budget for that so they light everything from all angles so they don't need to change things between scenes. The problem is that gives a characteristic look to the end result, something people come to associate with a less polished end product.", "Great minds think alike. Ahoy, matey! Yer not alone in askin', and kind strangers have explained: 1. [ELI5: Why do soap operas look and feel so different than other types of TV shows? ]( URL_6 ) ^(_6 comments_) 1. [ELI5: Why does it seem like soap operas are filmed with different cameras than regular shows? ]( URL_2 ) ^(_48 comments_) 1. [ELI5:Why do soap operas look \"different\"? ]( URL_0 ) ^(_3 comments_) 1. [ELI5: Why did \"soap operas\" always seem to have a higher definition picture than regular TV programming? ]( URL_4 ) ^(_ > 100 comments_) 1. [ELI5: What causes the difference in \"look\" between say a soap opera and a feature film? ]( URL_3 ) ^(_14 comments_) 1. [ELI5: why does motion in soap operas and home videos look different than motion in movies and tv shows? ]( URL_1 ) ^(_3 comments_) 1. [ELI5: How come I can always quickly tell a soap opera is on TV from even a single frame? ]( URL_5 ) ^(_14 comments_)"], "text_urls": [[], ["https://np.reddit.com/r/explainlikeimfive/comments/1b831f/eli5why_do_soap_operas_look_different/", "https://np.reddit.com/r/explainlikeimfive/comments/2aermi/eli5_why_does_motion_in_soap_operas_and_home/", "https://np.reddit.com/r/explainlikeimfive/comments/25swp6/eli5_why_does_it_seem_like_soap_operas_are_filmed/", "https://np.reddit.com/r/explainlikeimfive/comments/3shntk/eli5_what_causes_the_difference_in_look_between/", "https://np.reddit.com/r/explainlikeimfive/comments/3pv3xg/eli5_why_did_soap_operas_always_seem_to_have_a/", "https://np.reddit.com/r/explainlikeimfive/comments/30e2o4/eli5_how_come_i_can_always_quickly_tell_a_soap/", "https://np.reddit.com/r/explainlikeimfive/comments/2c19b8/eli5_why_do_soap_operas_look_and_feel_so/"]], "score": [12, 5]}}, {"q_id": "bgipdq", "category": "Repost", "title": "How do websites know when you are using an adblocker?", "title_urls": {"url": []}, "selftext": "I remember a few years ago, I would be able to use my adblock without getting any pop ups telling me to turn it off, but as of late I see an increasing number of websites telling me to turn it off before proceeding? How do they know? Isnt an adblocker only on the client's screen?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ell4e92", "ell4p37", "ell4zgo", "ellh2j9", "ellnhls", "elm0uk8", "ellkjm8", "ellggsc", "elm5sax", "ellf2k6", "elluo14", "elljowv", "ellgday", "elm37th", "ellhhrr", "elm285x", "elmgjtx", "ellhefr"], "text": ["In simple terms, they attempt to create an object which adblock blocks, then they run a script to detect whether the object exists or not. If they can't find the object they know you are running a blocker.", "Another way some sites do this is to layer the ad over the top of the message asking you to turn off the blocker. This way, if the ad loads properly, you wouldn't see the message under it.", "Well you're still running a script that does something to your browser, in general everything your browser \"knows\" is data you can check. So if there's a script running on said website that \"sees\" the changes adblocker makes to your browser they can basically tell a script on this website: IF you see THIS happening THEN you show a window AND you keep showing this window UNLESS you don't see THIS anymore. Sounds a bit stupid and it's a bit more complex to make it work but thats basically what you'd do to make something like this happen.", "If you open a paper magazine, there are ads on a lot of the pages. The only way to not see the ads would be ripping those pages out. There's nothing the publisher can do to stop you from doing that, but you'd be seeing the ads before ripping them out anyway. On a web site, a computer somewhere else sends a \"recipe\" to your computer to tell your computer what to show on your screen. It goes something like this: \"on this part of the page, show this text; on this part, show this image; on this part, show this ad.\" If you tell your computer you don't like ads (by installing an ad blocker), it will ignore any parts of the recipe that tell it to show an ad. It's like you're paying a friend to rip the ads out of the magazine before you read it. The publishers don't like that, because then they can't show you the ads, and they lose money. So they changed the recipe a bit. Now the recipe says, \"in that part of the page where we already told you to show an ad, check if there is actually an ad. If there is, cool. If there isn't, then show this message instead.\" Essentially the recipe is checking itself to see if it was made \"correctly,\" the way the publisher intended it to be. It's generally easier for an ad blocker to block an \"show an ad\" part of the recipe than it is to stop the recipe from checking itself to see if it was made correctly. The primary reason is that almost all ads are delivered by certain computers that are known to do nothing but show ads, so your computer knows to ignore anything it sees coming from those certain computers. That would be like you being allergic to walnuts, so you decide to not add any to your brownies even though the recipe calls for it. Finding a self-checking recipe, on the other hand, involves extra steps that are complicated to design and easy to thwart, especially because you don't want your computer to accidentally ignore an essential (non-ad) part of the recipe.", "Adblocker is only on the client's screen. Meaning, they ship a JavaScript script with their website that shows the nagscreen and hides the content. However, this also means that your browser still downloaded the entire site. And you can easily reverse the effects of the JavaScript that messed up your site with the nagscreen, if you know a bit about Html/CSS: Modern Browsers let you directly edit what is shown. For example, in Firefox, right click and inspect the background of the nag screen. It will take you to the html code of the site you are currently watching. Delete the element in the tree (by selecting it and pressing \"delete\"), then go up the element tree and continue to delete elements until the nag screen is gone. But the main content is still cut off and not scrollable. That is simply done by the script adding the property \"overflow: hidden\" on the main body element and the one above or below that. Scroll up in the element tree until you find the body node, click on it and disable the \"overflow: hidden\" property on the right side of the window. Then go up and/or down a level and disable the other \"overflow: hidden\" property on the other element. And now your site is fully functional, without disabling your adblocker.", "I just stop going to every site that does this. They should've been happy with my traffic but they squandered it =D", "Related question, kinda: How do compainies know you viewed their email? For example, i've gotten emails from a credit card saying that i needed to verify i was still using the account. Once i open the email, id get an immediate follow up email saying it was confirmed i was using that email address. Seems shady companies get notified when an email is open.", "Ad blocker browser extensions also have specific IDs, and the browsers themselves expose methods to see if an extension is installed by ID.", "Server: Puts ad333542.jpg on webpage that user 333542 asked for. User: does not download ad333542.jpg from server. Server: UfokingWOTM8?", "Many, many ways. The ELI5 is that they have different \"tricks\" to detect if their ads are not shown. If an ad is blocked, they can see that change being made and a message pops up asking you to disable it", "I take an odd pleasure in blocking those pop popups, even if the page refuses to work once it's gone.", "The website is a flash light shining at a wall. The ad blocker is your hand making shadow puppets that block out ads from showing on the wall. & #x200B; The website looks at the wall to see if there are shadow puppets.", "> Isnt an adblocker only on the client's screen? Yes, but the web page is also on the client's screen, executing code (javascript) on the client. In the simplest terms, that javascript code has access to your browser and can tell if ads are being blocked between the client (browser) and the ad server.", "I use a PiHole on my network, it's a DNS sinkhole, as far as page scripts are concerned, the ad servers are unreachable, so far I have not had any adblock detection scripts pick it up. You need a Raspberry Pi and some knowledge of networking to get it set up, or I believe there is a version of it that will run on a normal PC. I have the alternate DNS set to Quad9 versus the default Comcast DNS servers for further protection. [ URL_0 ]( URL_0 )", "Heres a fix. Use uBlock origin as your adblocker and then add nano defender aswell. Then follow the instructions on nanos defenders chrome store page. This assuming that you are using chrome and not firefox, which would be a little bit different. After this the websites will no longer know.", "An ad blocker can't fundamentally tell whether something is an ad or not. It can only guess, based on filenames, etc. What the developers do is create something on the page that isn't visually shown to the user, but which the adblocker is likely to guess is an ad. Then the webpage detects whether or not it can find if that object was loaded. If it isn't, it knows that an adblocker is active, and it can do what it wants with that information.", "Having had to deal with a zealous anti-adblock website operator, there are many many ways. Most of them have to do with the fact that the adblocker is modifying the source of the page. The anti-adblock code can check for discrepancies after the page is fully loaded and the adblock has run, or even using a timer to check later. One already mentioned a lot is checking for an object. One is hashing (using a function to turn data of any length into a string of very short length) the source of the website and checking if the hash matches a precomputed hash of the unmodified source. Another is checking the time the page takes to render. Above mentioned guy would dissect every adblock workaround to add his own workaround to the site, so I'm definitely missing/forgetting a few. I believe an adblock expert posted a full rundown of the battle at some point.", "You see everything on a website is created by a set of words called code, code is how we create programs in a sense. So if you think of it like a story code would be the words that make up sentences. The scripts would be complete sentences that make up pages. The program would be the entire story. So add blocker would be like an eraser getting rid of scripts (sentences) in a story. The program thats run on the website would check for specific sentences that are missing from the story. Specifically theirs hundreds of ways to check. An example to check would be like a test on a story you'd get in elementary school. So you've supposedly as the student (user) read the story that was given by the teacher (program), but in your case you skimmed and just Wikipedia'd(adblocked) the plot so the story(webpage) you know is a summary of the story leaving out all the intricate details. Which would usually work for a test, as its not exactly practical for the (program) teacher to make you write out the entire book verbatim as your answer. Usually you'd get away with the wiki'd summary of the story you didn't read, but the problem is everyone in the entire class used the same exact wiki'd article (adlbocker) for their \"summaries\" of the story. So the teacher (program) checks for the specific wikipedia article and cross references it to the summaries of the story that are an exact copy. yeah i don't know if the example helped."], "text_urls": [[], [], [], [], [], [], [], [], [], [], [], [], [], ["https://pi-hole.net/"], [], [], [], []], "score": [8617, 1053, 197, 153, 105, 11, 11, 9, 8, 6, 5, 5, 5, 5, 3, 3, 3, 3]}}, {"q_id": "bhyd2p", "category": "Repost", "title": "The folding paper thing. Where apparently if you fold a piece of paper 103 times it's thicker than the universe. I read this today and it doesn't make sense to me.", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["elwmyk1", "elwmy04"], "text": ["If you fold a piece of paper, it\u2019s thickness is now equal to 2 pieces. Fold it again and it\u2019s now 4 pieces thick. It doubles every time. When you fold it 103 times, it\u2019s thickness is 2^103 = 10 Million Trillion Trillion pieces thick. If each piece is the 0.1mm thick, the total thickness of that folded paper would be 1 trillion trillion km, which is indeed thicker than the universe is wide. However, it is impossible to fold the paper that much. Each time you fold the paper, it\u2019s area decreases by half. Eventually the area of the paper will become so small, it becomes impossible to interact with it. Assuming you start with a humongous 1km x 1km sheet of paper, folding it 103 times will result in the length of the paper becoming. 44.4 picometers wide, or half the size of an atom.", "Great minds think alike. I've sailed far and returned ta port with this booty. Yer not alone in askin', and kind strangers have explained: 1. [ELI5: Is it REALLY impossible to fold a piece of paper more than 8 times? ]( URL_6 ) ^(_9 comments_) 1. [ELI5: Why can paper only be folded 7 times, no matter the size of paper? ]( URL_1 ) ^(_18 comments_) 1. [ELI5: How can a piece of paper folded 103 times be larger than the observable universe? ]( URL_2 ) ^(_._) 1. [ELI5: Why you can't fold a standard sheet of paper more than 7 times ]( URL_4 ) ^(_9 comments_) 1. [ELI5:how does a piece of paper that is folded 50 times reach the sun? ]( URL_0 ) ^(_9 comments_) 1. [ELI5: How can folding a paper 42 times reach the moon? ]( URL_3 ) ^(_18 comments_) 1. [ELi5: how would folding a piece of paper 42 times make it reach the moon? ]( URL_5 ) ^(_19 comments_)"], "text_urls": [[], ["https://np.reddit.com/r/explainlikeimfive/comments/373o9w/eli5how_does_a_piece_of_paper_that_is_folded_50/", "https://np.reddit.com/r/explainlikeimfive/comments/8w8rbo/eli5_why_can_paper_only_be_folded_7_times_no/", "https://np.reddit.com/r/explainlikeimfive/comments/7frj2o/eli5_how_can_a_piece_of_paper_folded_103_times_be/", "https://np.reddit.com/r/explainlikeimfive/comments/20xmib/eli5_how_can_folding_a_paper_42_times_reach_the/", "https://np.reddit.com/r/explainlikeimfive/comments/4akwrg/eli5_why_you_cant_fold_a_standard_sheet_of_paper/", "https://np.reddit.com/r/explainlikeimfive/comments/2aep56/eli5_how_would_folding_a_piece_of_paper_42_times/", "https://np.reddit.com/r/explainlikeimfive/comments/3vyain/eli5_is_it_really_impossible_to_fold_a_piece_of/"]], "score": [10, 8]}}, {"q_id": "clqxx2", "category": "Repost", "title": "What exactly is glass? How is it clear? Could you 3d print glass?", "title_urls": {"url": []}, "selftext": "Is glass a naturally occuring thing?", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["evx8r9w", "evx9g2z"], "text": ["Glass is typically comprised mainly of silica sand, which is just ground or otherwise broken down quartz crystals. Quartz itself is clear, and when you see a large piece of quartz, and cloudiness is either from impurities or flaws in the crystal structure that refract light making it appear less transparent. Theoretically you could 3D print with glass, but it would be a pretty specialized printer that you would need. It would have to melt the materials, close to 3000\u00b0F, and then it would have to maintain a high temperature for all of the glass you've already printed to prevent the glass from cooling too unevenly and cracking. The main problem with the printer would likely be that it would be difficult to support the glass as you print it, it would still be in a liquid state and would try to settle with gravity. This is why glass blowers have to keep their blown objects constantly moving and rotating so that all sides deform as evenly as possible. And finally, yes, [glass can be created in nature]( URL_0 ), the only example I am familiar with is when lightning strikes on a sandy area. But, it isn't glass like we think of glass, because it's not all melted evenly, and so it's usually more like a fused chunk of sand than a glass window pane.", "Others have pointed out how glass is made, but maybe I can help with the rest of your question. Glass is something called an \"amorphous solid,\" that sounds complex, but isn't. If you take a sheet of stainless steel, and look at it under an electron microscope you'd see that the atoms are arranged in a fairly regular crystal lattice. Because of the way that a material like that is structured, and because of its electronic properties (as in, how the electrons in it in behave) light will be rapidly absorbed or reflect near the surface. In glass however, there is no such regular order, and the electronic structure is such that light *can* pass through it. Of course this is not the only kind of substance light can pass through, but I can't think of a way to ELI5 exactly why that is. I can give you an example like ALON (ALuminum OxyNitride), which is a crystalline solid and quite transparent in the wavelengths we use to see. That last bit is the key; it isn't generally transparent the way glass is, it's really just transparent in a broad section of the visible spectrum. As for naturally occurring, yes. Glass is routinely formed from volcanic activity; you've heard of Obsidian right? That's volcanic glass. You can also find glass formed when lightning strikes sand of the correct composition, as a result of meteorite/asteroid impacts, etc. And yes, you can 3D print glass, and it has been done before."], "text_urls": [["https://www.mnn.com/earth-matters/climate-weather/stories/fulgurites-when-lightning-strikes-sand-magic-is-formed"], []], "score": [34, 8]}}, {"q_id": "cmmnps", "category": "Repost", "title": "When you hear something like \"The Dow is down 500 points\" what does this mean? Specifically the \"points\" part", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ew3ykn3", "ew49w4b", "ew3bdka", "ew48s4z", "ew3xg69", "ew3c91d", "ew42sx5", "ew44y4v", "ew3y01y", "ew43j43", "ew580b9", "ew48wop"], "text": ["Lot of mostly correct stuff below, but here's the ELI5 skinny: Over a hundred years ago, a guy named Dow came up with a concept of tracking \"the general market\", instead of each individual stock. He, along with a stats guy named Jones, created an index called the Dow Jones Transportation Index (DJT) in 1884 - this was a price-weighted index of (initially) nine railroads; eventually this grew to 20 companies in areas such as freight, airlines, etc. In 1896, they added the Dow-Jones Industrial Average (DJIA) of 30 major industrial companies. (The industrials are what most people think of when they refer to the \"Dow\".) Finally, the Dow-Jones Utility Average of 15 major utilities - electricity, gas, etc. - was created as well. Together, they form the DJ65, although that is not followed as closely as the DJIA. Each index was an attempt to gauge the overall movement of the market. For example, suppose Exxon is up $3, but GM is down $1.50, while Caterpillar is up $0.75 but Apple is down $1. Did the overall market go up or down that day? All stock indices attempt to answer that question. The Dow is considered the narrowest of these indices, as it only includes 30 stocks, whereas the S & P500 contains 500 stocks, and the Russell 2000 and Wilshire 5000 contain even more. One of the tricks to keeping the index meaningful is adjusting for stock activity (like splits), and for corporate activity (many companies have been removed from, and added to, the Dow over the years). For example, Apple splits their stock 2:1, so what was a $100 stock is now $50. How does this get reflected in the average? The DowJones people came up with a mathematical technique to adjust for this called the Dow divisor, which is too far beyond ELI5 to explain here. In addition, some companies fail. For a long time, Woolworth's was a member of the Dow, but in the early 1990's, after many terrible years, it was removed from the DJIA, and replaced by Wal-Mart. Similar fates have befallen such former stars as Western Electric, Bethlehem Steel, US Steel, and International Harvester. Each time a company is added/removed from the list, the Dow is recalculated so that the effect of the change isn't noticeable. This allows us to use the index over the years. A fall of 500 points today is not the same event as a fall of 500 points in the 1960's, because the index is so much higher. In the 60's, the Dow was trying to top 1,000; today, it's about 25,000. A fall of 500 points in 1968 would have been 50% of the Dow's value, and would have been a catastrophe, but a fall of 500 points today is 2%, and while troubling, is not nearly as bad. In general, rising markets signal confidence in the economy and business; falling markets signal the opposite. But one day's movement is generally just noise; you need to look at longer trends to see what's happening.", "PSA: The Dow is actually a pretty crappy gauge of the stock market. The only reasons why it still gets referenced are: 1) tradition and 2) Dow Jones owns one of the best financial news sources in the world (Wall Street Journal). It\u2019s the WSJ\u2019s one flaw, in my opinion. Better stock index: S & P 500, which is market cap weighted (instead of stupidly price weighted like the Dow). And the S & P 500 tracks the largest 500 stocks (instead of only 30 industrial stocks like the Dow). Even better stock index: Total US Stock index, like VTI for example (Vanguard Total Stock Market ETF). This index includes essentially all US public stocks, so there are 3,600 companies in it instead of only 500 like the S & P 500 or 30 like the Dow. Even better stock index: Total WORLD Stock index, like VT for example (Vanguard Total World Stock ETF). This index includes essentially all public stocks in the world, so there are 8,300 companies in it instead of only US ones like VTI or only the large US ones like the S & P 500 or only a few large US industrials like the Dow. Context is key \ud83d\udd11", "The Dow is an index of the market. It indicates how the market as a whole on average is doing. The points is referring to the current Dow value. Let's say the Dow is 25,000 today but falls 500 points tomorrow. The Dow would then be at 24,500. This is a fall of approx 2%. The largest companies on the stock exchange make up the Dow. The company themselves did not lose 500 points. As companies are not valued in points but in dollars. On average across the board the largest companies lost 2% of their market value. This does not mean all companies lost share value, just on average across the board they lost 2%.", "Sounds like the OP really wants to know what an INDEX is. I'm not a finance expert but maybe someone can build off of this: As people have said already, the Dow or other market \"indexes\" are an attempt to measure the health of the economy. They look at the performance of a group of stocks. The price of each company's stocks may go up or may go down independent of how other companies are doing. The index provides a big-picture look across multiple companies. If I asked you to give me a snap shot of how these companies are doing on a day-to-day basis, you might be tempted to give me the AVERAGE of all the companies' stock prices over each day. Like tracking the average price of milk/gallon over time. However, stock from company A is not the same as company B. When you buy stock in a company, you're actually buying something called a \"share\". Different companies have different number of shares. A share is very much what it sounds like; if I had a pie and I wanted to share it with multiple people, I'd cut it into several slices. But how many slices? Now if I wanted to sell a piece of that pie, how much would I sell it for? What's worse is that I can change not only the price per piece of pie, I can change the number of pieces (shares). Let's say there are other people selling pie, but some people have bigger pie, smaller pie, pies with more pieces, less pieces, and the prices per piece are all over the place because maybe apple pie is selling better than peach at this time of the year. Now I ask you to tell me how the pie market is doing, accounting for all of these differences. It probably seems like taking an average of the price/piece of pie doesn't really cut it. So instead you, you make a pie \"index\" which is just a fancy way of saying, you're looking at multiple VARIABLES or PROPERTIES of each pie provider, not just comparing price/pie. You take into account how large the pie is, how many pieces there are and how much people are willing to buy the pieces for. Maybe you can come up with some other useful properties to measure the health of the pie market. Then you take these variables from all of the major pie companies, put them into a fancy formula you've developed where you multiply things or divide things and at the end, you get a number. Though this number might have something called a \"unit\", like \"$/lb\", it's probably something very complicated and ugly. So you decide to make your pie index sound cooler, and you name the number that your formula spits out a \"point\". It sounds way better to say that the pie market has increased 10 pie points rather than 10 $/cubic-inches-of-pie/piece-of-pie (yuck). Lastly, let's say you were looking at 10 different pie providers for your index (even though there are many others who produce pie). Suddenly, peach pie--one of your 10 providers--goes out of business. If you took the average of share prices, this would be a HUGE deal. But you were smart and accounted for multiple variables which does something called NORMALIZING. This means, regardless of the price per piece of pie, you can swap pecan pie in for peach pie and your magical \"points\" aren't affected that much. This makes your pie index way cooler than a boring average! Fun fact, similar mathematical gymnastics (indexes) are used in science and engineering (but the units are different). // TL;DR: Indexes help compare the performance of dissimilar things. In the case of the economy, stocks from Company A are not the same as Company B so if you want to look at the performance of a market as a whole, you need to create an \"index\" which looks a many important properties of a stock. Because indexes look at many properties, the actual units of the index are complicated and \"points\" is used because it sounds better.", "The Points are referring to the general dollar value of the stock based on how many people are trading it versus own it. And the Dow is just an average of all the stocks in its index, so if one company has a bad day, the Dow doesn't move much. If multiple companies in the Dow index have a bad day, the Dow suffers and its average moves down. While usually a sign of bad news, sometimes it is an overreaction where people sell to protect their investment but repurchase days later. So, the Dow could be down 789 points today, but by next week it has gone up 1500 and recovered all that was lost.", "Dow Jones Industrial Average is a stock market index made up of 30 large companies in a variety of sectors (some examples are Apple, Home Depot, Johnson & Johnson, American Express), it\u2019s used as a general gauge on the stock market. It has lately been trading around 26,000 points but today fell almost 800 points, or almost 3%, suggesting investors have strongly negative feelings toward recent Trump trade decisions and how those will impact the economy.", "One thing that is kind of funny is that everyone will tell you that the S & P 500 is more relevant--and they are right, and this is something I've known for like 20 years--but I always look at the Dow first. If you follow baseball, the Dow is kind of like batting average--it's a benchmark that's been around a long time, but other far more useful measuring sticks have been developed since. And I still look at batting average first before looking at WAR or OPS. Old habits die hard.", "You know how in Civilization games at a certain point you can see every civ's score giving you a general idea how everyone is doing? If suddenly every civ's score dropped like 50 points in one turn (which is unlikely but let's just say) then you know something really majorly f'd up just happened in the game.", "**edit** This comment is NOT correct. Please ignore. Leaving the comment up so others might learn. Beginning of incorrect comment: A point is a dollar. When a stock is being traded at $5.00 per share on Monday, then on Tuesday it is being traded at $4.00 per share, that stock has gone down one point.", "It's a barometer for the stock market. It's a small group of stocks that are meant to represent the stock market as a whole. This basket of stocks are blended into an average, and based on the movement of each of those stocks the Dow moves based on a weighted average. Without trying to sound like a crazy person: The headlines make it sound really great when you hear am absolute number \"500 points\" \"700 points!\", but in reality, you need to look at the percentage that it moves. 3% - while not minor - doesn't have the same \"oh shit!\" impact as 700 points.", "* Take the 30 stocks that are in the Dow * Add up all the prices (if the Dow was made up of 2 stocks, stock A and B, with prices $1/share and $3/share, you would be at $4 on this step) * Divide by the Dow divisor. This is a number that can only be computed by historical averages, so it\u2019s hard to pin down exactly how it\u2019s calculated. For now, it\u2019s roughly 0.14 The number you got is the Dow. Everyday the prices change, and the Dow divisor stays relatively the same. So when all the prices go up, the Dow goes up. The number the Dow increases by is the \u201cpoints gained\u201d.", "You walk into a arcade game room full of pinball machines with different scores. A manager named Dow wants an idea how high all the high scores on his machines are at any given time. He compiles a list of his 30 most popular pinball machines and combines them into an index. Index like average (weighted) of the high scores of those 30 machines. He comes into work one day and all of a sudden, the index (average) of those machines is down 500 points b/c player's aren't playing and demanding refunds on the quarters they spent on the 30 machines. He exclaims \"OMG THE PLAYERS TODAY SUX!! Bringing my arcade average down puny noobs F\\*\\*\\*! Sh\\*t i'm losing money, my owners are going to be pissed.\" The next day he comes in and the index (average is up 1000 points, he exclaims \"BOO YEA worthless players finally improving. Hope they pump more quarters into those machines and keep setting new high scores. My owners gotta get paid so i can have a job.\" In real life terms, the Dow index being down 500 points just means more people are selling their stocks than people buying stocks for the 30 large revenue companies in the Dow Index. 500 points is nothing to be scared of. If it was 5000 i would be worried b/c when more people sell stocks than buy, it usually signals a recession coming. Quarters = money buying stocks. Owners = investors, pinball machines = companies stocks."], "text_urls": [[], [], [], [], [], [], [], [], [], [], [], []], "score": [5445, 199, 150, 31, 27, 23, 18, 5, 3, 3, 3, 3]}}, {"q_id": "cqfzhk", "category": "Repost", "title": "How can I dose off a few seconds after closing my eyes while on a bus/train home, yet if I crawl into bed as soon as I get home it takes more than ten minutes to fall asleep?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["eww4iny", "eww57u6"], "text": ["Much like a smartphone, your body will go to sleep when there are no new inputs. When you are on a bus, your senses will give you the same repetitive inputs. The streets will flow by, the AC and engine adds a constant white noise, you're seated and not moving, and the smell... well you hope the smell doesn't change. Any repetitive input going to your brain will eventually get ignored and your brain will start going into a low energy state. The fact that you fall asleep quickly when closing your eyes on a bus is because you were already been on the bus for a while and got used to all the repetitive sensory data. When you go to bed, you have a lot of new changes. You are lying down, you wear different clothes, you feel the pressure of your covers, you go from bright to dark, noisy to quiet. All of these are new sensory inputs that your brain needs to get used to before going to sleep. God forbid if your brain starts thinking about other things! Those 10 minutes to fall asleep on the bed is your brain getting used to the new senses of being in bed. One way to shortcut going to sleep is to be exhausted mentally and physically. Your brain will skip many steps and quickly activate sleep.", "So I\u2019ve actually read a bit about this because I\u2019m a structural dynamicist (acoustic, shock, and vibration). From what I understand, our brains have low frequency delta and theta waves\u2014something like 0.5 to 8 Hz. This frequency just so happens to correspond to automotive vibration. Ford even recognized this and built a baby vibrating car seat that mimics road vibration. This is why babies fall asleep during a drive. So in other words, driving can actually make you sleepy. As to why you stay awake once you\u2019re in bed, there are probably multiple physiological and psychological reasons: stress, anxiety/worries, and the obvious \u2014 > caffeine too late in the day, but I\u2019m not an expert in this area."], "text_urls": [[], []], "score": [108, 6]}}, {"q_id": "d0il1q", "category": "Repost", "title": "Why wet slaps hurt more?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["ez9w9ig", "ezael1k", "ezaa0mo", "ezaj7yi", "ezbae10"], "text": ["Skin is soft, mushy, and full of lots of little cracks and holes. When you slap someone, a lot of the force from the slap gets cushioned by the skin and dissipated over the larger surface area created by those little uneven surfaces. This happens for both your hand and the slapped person. When your skin is wet, it pulls itself taut to help keep that moisture out. This tightens it out a bit to reduce surface area and makes it slightly less mushy. In addition, the water fills in some of the cracks and holes, making the surface more uniform. This reduces the energy lost and makes the slap hurt more. If you wait even longer while wet, like long enough for your hand to get all pruney, the opposite will happen. All of those wrinkles increase surface area and make the skin even mushier, and so the slap will hurt even less.", "Good god! I asked this question on a whim I didn't know reddit was waiting for it.", "It is surface area. The water fills the gaps in your skin of the hand and surface of the other area. Evenly dissipating the power of the slap onto its target. Creating more efficient energy transfer. You ever tried to hit something, swing hard and just not get enough hand on it. Like a volleyball serve where your fingers engage before your palm, it will not go as far because you did not evenly transfer the power.", "the other commenters are mistaken, i think. it\u2019s not a surface area thing, it\u2019s an air cushion thing. the pain of a slap comes from the linear kinetic energy of the slap being transferred to the struck skin, and air lets some of the linear force become transformed into motion in a random direction via turbulence and subsequently into sound and heat. by making an airtight seal, a slap that occurs at a wet palm/skin interface compresses all of the air at once. you can think of it as a wrinkled vs a flat surface striking skin. as the rough surface comes toward the skin, the taller peaks of the surface will be \u201csquishing\u201d the air faster than the troughs, so those areas will experience a sharper rise in pressure. the adjacent troughs will be at a lower pressure and air will flow sideways to equalize this, stealing forward momentum that could otherwise be spent on pain. there\u2019s only so much force behind the slap, and moving air isn\u2019t free. more force spent pushing air sideways means less force pushing meat hard enough to hurt, less force means less pressure. well, the why of a wet slap hurting more probably has something to do with the fact that the acceleration is happening quickly. i don\u2019t know why sharper acceleration is more painful, but i\u2019m pretty sure that\u2019s the cause.", "Its because water is not compressible, for the same reason that water is like concrete when an object hits it from a great height."], "text_urls": [[], [], [], [], []], "score": [16384, 527, 127, 28, 12]}}, {"q_id": "d4j294", "category": "Repost", "title": "Why does \"Hoo\" produce cold air but \"Haa\" produces hot air ?", "title_urls": {"url": []}, "selftext": "Tried to figure it out in public and ended up looking like an absolute fool so imma need someone to explain this to me", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["f0cx6q2", "f0dd5g3", "f0daccn", "f0dcqre", "f0ddj6n", "f0ede21", "f0dc2gj", "f0dysww", "f0dldmx"], "text": ["When you do a \"hoo\", the air is coming out from a very small opening which gives it a higher chance to mix with the air around it and cool down. When you do a \"haa\", the air is coming out at a larger volume and needs more time to cool down. **Edit** Put your finger right in front your mouth when doing a \"hoo\" and you will sense that it's actually just as hot as a \"haa\", but cools much faster a few cms away.", "There's two things to note here: 1. The human body doesn't feel absolute temperature, what you feel is how much heat is entering (hot) or leaving (cold) your body (That's why metals always feel a lot hotter or colder than their surrounding, high heat conductivity). So in the case of your breath, the air comes out faster on the \"Hoo\" sound. A faster flow of air will carry more heat away from your hand via convection. As someone else pointed out, it is the same reason a fan cools you down even though the air doesn't get any colder. 2. The reason the \"Hoo\" sound produces a faster airflow than the \"Haa\" sound for the same effort has to do with the opening size in your throat. If your lungs are pushing the same amount of air in both instances, the air will have to come out faster if the opening is smaller. Think of a garden hose when partially block the opening with your thumb, the water comes out faster!", "What you go \"hoo\" the air your pushing out of your lungs increases in pressure as it moves through the smaller opening in your lips and then quickly decreases in pressure after it's left. This decrease in pressure reduces its temperature because the air particles are moving further away from each other, dissipating their energy into kinetic rather than thermal. When you go \"Haa\" there is less of a pressure difference between your lip opening and the outside air than when you go \"hoo\" so the pressure change is lower so more thermal energy is kept in the air. Therefore, when you go \"Haa\" the temperature of the air is closer to the temperature in your lungs. Its the same reason that you can feel your deoderant can getting cold when you hold the nozzle down for a while. The pressure in the can is decreasing as you let the gas out. Edit: This affect is known as Gay-Lussac's Law (aka The pressure temperature law)", "When air moves fast out of the mouth, it sucks in ambient air, which is colder. To test this, blow (\"hoo\") on the palm of your hand through a \"tube\" made of the other palm (make sure it's tight), or a toilet paper tube. It has nothing to do with \"compression\" or Bernoulli principle.", "I disagree with the answers referring to drop in pressure (adiabatic effect), since the pressure difference just isn\u2019t sufficient. Instead, the answers around speed are more accurate. The body is pretty warm, and the more contact that the air gets with us, the warmer it gets. Even then, rapid air over the surfaces (like our mouths and throats) tends to cool them, so the slower the air is, the more chance the body can keep those surfaces warm with circulating blood. Also, while \u201choo\u201d moves air faster, \u201chaa\u201d has greater turbidity around the vocal chords, which means that the air gets more stirred up and more of it gets in contact with the warm surfaces.", "The temperature should be close to the same, but fast moving air wicks away more heat than slow moving air. The \"hoo\" motion involves pursing ones lips closer together so the air coming out moves faster because of the higher pressure inside the mouth. The \"haa\" motion involves leaving ones mouth more open, the air coming out moves slower because of the low pressure inside the mouth. If there was anything more to it, I think its possible that the temperature of the air is coming from the lungs, and when you say \"haa\", that the total volume of air comes out more quickly and so does not have a chance to cool down. When you say \"hoo\", the total volume of air comes out more slowly, and probably cools down as it passes over your lips, which are much cooler than the core of your body", "Think of what some people do to clean their glasses. When you do a haa you get wet from fluids at your own body temperature, and so feel warm. When you do a hoo the air is faster which means you don't get wet and you feel a cooling sensation from evaporation. The faster the air the cooler. The pressure theories are wrong since the air is at a lower temperature that your body already. Even holding your breath for 5 minutes will barely increase the temperature of the air inside your lungs. Also you can't create much pressure with a simple hoo. It's more about sensations than air temperature itself.", "Holy cow, there are so many wrong answers here from folks trying to look smart with complicated answers. It\u2019s really simple: with \u201choo\u201d you\u2019re blowing a small and directed stream of air quickly, so it brings along the typically cooler atmospheric air with it. With \u201chaa\u201d, you have a larger and slower outflow that does not pull along the surrounding air as much. That\u2019s it. See \u201centrainment\u201d and URL_0", "This is the same principle that applies to EcoCooler, an air conditioning system that doesn't use electricity: \"As hot air rushes into each plastic bottle, it is pushed to the rim where it begins expanding. This expansion then leads to the cooling of the air as it enters the target room. This cooling results from pressure change. As air enters the plastic bottle\u2019s wider part it comes out the bottleneck with higher pressure. As it quickly disperses into the room, its temperature drops. Sounds uncanny, right? The principle here is quite simple actually. With your mouth wide open, blow some air onto your hand. Does the air feel hot? What if you do the same with pursed lips? Does the air feel cool? That is exactly how the Eco cooler functions!\" URL_0"], "text_urls": [[], [], [], [], [], [], [], ["https://physics.stackexchange.com/questions/7868/why-does-the-air-we-blow-exhale-out-from-our-mouths-change-from-hot-to-cold-depe"], ["https://www.quora.com/What-is-an-ECO-cooler-and-on-which-principle-does-it-work"]], "score": [9511, 7057, 121, 17, 17, 17, 4, 3, 3]}}, {"q_id": "eo8osl", "category": "Repost", "title": "How come we still use steam moving dynamos to convert energy into electricity? It seems antiquated that even something as advanced as nuclear reactors still rely on this process. Are there obstacles in designing a better energy/electricity method?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["fea0oal", "fea17c7", "fea1aty"], "text": ["Water has some stupendously useful properties. It's easy to boil, and steam is able to store a great deal of heat energy without coming apart into hydrogen and oxygen. That heat energy can be converted into electricity at high efficiency using a turbine, a device with only two moving parts. In addition, water is environmentally friendly, if you spill it on the ground, no messy cleanup. It is everywhere **and** it is cheaper than almost any other substance at a constant purity level.", "You have to realize that the method depends on the kind of \"energy\" you're talking about. Solar panels convert electromagnetic radiation (light) to electricity, hydroelectric dams convert gravity to electricity (via water fall / water pressure), and batteries convert chemical reaction energy to electricity. And the obstacle is materials. We don't know of a material that would convert radiation (such as in nuclear reactors) to electricity, and we don't have a material that efficiently converts heat to electricity ([there are materials]( URL_0 ) that generate some electricity from heat, but not on the grand scale that we consume). So, ultimately, boiling water to generate pressure to turn turbines, however inefficient the process, ends up being the best large scale method we have. Convert heat to pressure/motion, then pressure/motion to electricity (using magnets and copper wires). There's a lot of chemical energy stored in the stuff that we burn (burning is a chemical reaction), much more than what we can achieve with the chemical reactions in batteries.", "Relatively speaking, the use of steam turbines if pretty efficient due to the excellent heat transfer properties of water. So it falls in the category of \"if it aint broke, dont fix it\"."], "text_urls": [[], ["https://en.wikipedia.org/wiki/Thermoelectric_effect#Seebeck_effect"], []], "score": [37, 9, 3]}}, {"q_id": "jlzdlk", "category": "Repost", "title": "Why do we have knee caps but not elbow caps", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["garznhx", "gas71xx", "gas20hi", "gasay0s", "garzny0", "gashcxp", "gatdoxz", "gashuk7"], "text": ["Our legs and knees bear a lot of stress due to our walking upright. The muscles in our upper leg are the biggest and most powerful in the body. The quadriceps muscle is responsible for extending the leg - when it contracts, it pulls on the tendon that runs over the front of our knee, which extends our lower leg. This tendon runs more or less right over the kneecap. What the kneecap does is act as a fulcrum - it moves the tendon away from the knee joint's point of rotation, just a little, but enough to provide a significant mechanical advantage. It actually makes the quadriceps muscle about 30% more powerful than it would be without it. [Here's a YouTube video showing how it works.]( URL_0 ) As we generally don't walk around on our hands, our elbows need no such mechanical advantage.", "The ulnar bone has a fairly prominent process called the olecranon, wonder if it serves a similar function of moving the triceps pull of force into a more advantageous position about the joint like the patella does for the quadriceps? We talked about the knee in my biomechanics classes in regards to this but never the elbow. Could be as others have said, just don't need it as a bipedal organism.", "The knee cap is actually a bone that develops in childhood. Babies don't have them. It's a special kind of bone known as a sesamoid bone that forms inside the tendon to help take the forces exerted on the tendon by the large muscles of the thigh.", "Just an additional information: knee caps don't form till 18 months of age. Means, babies less than 1 1/2 years of age don't have knee caps.", "Your femur (thigh bone) and your tibia (shin bone) are sandwiched between a cartilage circle structure (meniscus). These bones are held in place through ligaments to prevent front, back and side movements to keep the bone in place. Your knee joint is actually quite an unstable joint in your lower limb, which has to support the weight of your body, which is why it needs more protection. In your elbow joint, there are two connections to the humerus (upper arm bone); one of these has a hook like end (ulna/forearm bone) which is very stable. Also, the elbow doesn\u2019t often bear a lot of weight compared to the knee. Hope that\u2019s clear!", "I see good ELi5 about the legs being stronk, but can we talk about how our radius can rotate around our ulnar letting us roate our hands? The tib/fib can't do that shit.", "A lot of these responses are why we need a knee cap but do not address why it is there in the first place. The answer is evolution. Our genetic and evolutionary lineage needed a bone in the knee and there was a bone there that could function in that way. At first it was not as effective but as walking on two legs became increasingly important to our ancestors\u2019 survival it was slowly changed over time. Arms and forelimbs work differently so there were different evolutionary factors that helped them to become different from the leg.", "The bone that we feel on our elbow is actually made up of the ends of our two forearm bones. The bone that we feel on our knee is its own bone called the patella bone. It is attached to strings called ligaments."], "text_urls": [["https://m.youtube.com/watch?v=XnYO4TnpTCo"], [], [], [], [], [], [], []], "score": [1949, 85, 36, 31, 29, 6, 6, 5]}}, {"q_id": "jtylta", "category": "Repost", "title": "Most hard drugs give you a hit of dopamine and/or serotonin. Why not just cut out the middle man and take straight dopamine or serotonin instead?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["gc8kjn5", "gc8stt2", "gc8to5l", "gc8tded", "gc8ydte", "gc8xnou", "gc8xzgf", "gc8ym6m", "gc90bb4", "gc90pd3"], "text": ["Dopamine, outside the brain, can dilate blood vessels in the kidney, increase cardiac output and lead to vasoconstriction respectively, depending on dose. Directly injecting dopamine therefore, will not lead to any kind of high, just an increase in blood pressure. This means if you want a high, you have to inject directly into the brain, which is difficult for obvious reasons. Even then, it may not be sufficient. In different regions of the brain, dopamine has different effects. Eg. if you introduce dopamine to the chemoreceptor trigger zone, vomiting will result. So, in addition to injecting into the brain, you must also target the correct region. In summary, dopamine should be treated only as an excitatory neurotransmitter that has different effects in different parts of the body.", "Also because 'feeling good' is the result of a very complex set of variables that just so happen to involve serotonin and dopamine and wack ton of other chemicals/reactions, while obviously important they're not the simple 'happy' molecules you could easily be led to think they were. the real answer to this is probably beyond ELI5 or at least for me but yeah.", "serotonin plays a role in the digestive system...so based on the side effects of SSRI'S lots of toilet time would be in your future", "You can take L-DOPA (precursor to Dopamine) and 5-HTP (precursor to serotonin). Both are able to pass the blood-brain barrier and stimulate production of the neurotransmitters in the brain. L-DOPA is used to treat Parkinson's. And 5-HTP may be used to help with depression.", "might be irrelevant to this post but i just want to say that more \u2260 better. too much of any brain chemicals can cause psychosis, mania, and so on. it\u2019s a very delicate balance.", "Neither serotonin or dopamine is able to cross the blood-brain barrier. Thus injecting them would do nothing for your brains. But like others have said both have functions outside the brain as well.", "Ever had serotonin syndrome? DAMN that shit ain't fun. Worst trip. Ended in a 20 minute seizure, even the diazepam injections weren't working.", "The drugs I assume you're referring to don't actually have serotonin and dopamine in them. These chemicals are already in your body. What the drugs do is over-activate the corresponding receptors in the brain.", "It's almost like taking a pure vitamin, it may go in the body as one compound but after your body metabolizes it, it becomes a different compound. Pure dopamine and serotonin will not be pure serotonin or dopamine once it reaches the liver and enters your blood.", "Your body manufactures and stores these naturally in vast quantities, they can be administered in certain ways and increase available supply but won't cause euphoric effect because the brain strictly manages and recycles them. Drugs work by tricking your brain into mismanaging them in various ways, for example binding to receptors to inhibit the re-uptake process causing dopamine to flood in your brain"], "text_urls": [[], [], [], [], [], [], [], [], [], []], "score": [4118, 157, 66, 46, 18, 12, 10, 5, 3, 3]}}, {"q_id": "g29knw", "category": "Repost", "title": "So how does the the human brain ignore the second the?", "title_urls": {"url": []}, "selftext": "", "selftext_urls": {"url": []}, "subreddit": "explainlikeimfive", "answers": {"a_id": ["fnk9cpm", "fnkirhq", "fnke8bi", "fnkld0z", "fnknhpu", "fnli2gl", "fnko4zq", "fnkuxen", "fnlz6rp", "fnknw21", "fnlzsvi", "fnknxpb"], "text": ["We don't actually read every word in a sentence. Our brains pick up the patterns and fill in the blanks as we skim along the text, which greatly increases our reading speed while doing very little to reduce comprehension. We do it with just about all sensory input, as well. We blank out while driving but still reach our destinations with no incidents, we tune out smells pretty quickly (no matter how bad the smell is), we tune out physical sensations (you're now aware of how your tongue is resting in your mouth, also you're breathing manually), we hit that autopilot button at work and just coast through it while thinking about the grocery shopping, etc. It's probably an evolutionary trait that evolved from a need to be vigilant against **unique sensory input**, like sudden movements and noticing things that aren't supposed to be there. We're good at recognizing patterns, and tune things out to reduce overall taxation from sensory inputs so we can instead focus on novel inputs. & #x200B; Small edit: I'm an English tutor, and one of the practices we use to catch those kinds of mistakes is to read the whole text backward. Doing this tricks the brain into not recognizing the speech patterns and causes it to focus on each word.", "Short version: Our brains are tuned for pattern recognition and prediction, not detail. That's also why things that break the expected pattern/outcome can be so jarring. Sometimes it's in a fun way, though. See movie twists, stage magic, joke punchlines and so on. It's a filtering mechanism. Ignore the leaves, see the broken up/partial shape or movement of the predator hiding behind them.", "We're too used to reading English that we don't actually read every word, but the sentence as a whole. (When I was learning Spanish in school I had to read every word and then combine them to understand what it means)", "I'm guessing people who are learning English won't skip it naturally as they are not used to the patterns and are more focussed on piecing together the meaning?", "Your brain doesn't take in information. It takes in patterns on information. I dotn haev to be detialed in my tpying for you to now wat I'm sayin. You can read what I just wrote. Just like you can understand the gist of a sentence with two thes. You get the pattern, and then you can disregruard.", "Brains are lazy. They are quick to guess, and they \"check\" the guess as lazily as possible. More accurately; brains need to be as fast as possible while using as little energy as possible, so we can out-compete everything else and not get killed - same as all life. That's what makes you successful; use the minimum resources to get what you need. Which is why life takes short-cuts - as long as they work more often than not... It applies to all levels of things; from your example, to people more readily believing things they already know more than anything new to them - regardless of reality.", "Your brain is very efficient (lazy). It can ignore redundancies unless you focus on them. A neat experiment to do ( but can be difficult) is if you stare at one point for a good amount of time, and I mean stare don't move your eyes even a bit, you'll notice it starts to disappear. Your brain is saying this is not new input so I will ignore it. Its why your eyes are constantly doing micro movements you may not notice and why when look from one thing to another quickly you don't see a blur but instead feels like your vision teleported.", "What we 'see' isn't what's actually there. It's the same as how we have a big blind spot in the center of our field of vision and our brain fills in the details. Our eyes detect light and send signals to our brain. Our brain interprets those signals and builds a model of the world that isn't necessarily accurate, but is usually good enough for us to function. Things like this show that the model built isn't necessarily accurate, but that details will be filled in by our brain based on surrounding detail. Another one is that I can type words incorrectly and as long as the first and last letters are present a quick raed show that your brain will fill in the detials and 'show' you the correct word.", "Superfluous information. Your conscious mind has what it came for and discards the rest. Think if it as data compression. Your typical mp3 song sounds indistinguishable from lossless wave yet it\u2019s a tenth of the size because all those high sounds you can\u2019t hear anyways gets discarded. Mostly these shortcuts are very useful to us but it can be a vulnerability to be exploited. Source: A whole lotta thinking about it.", "Human brains are very sophisticated pattern recognition machines. More sophisticated than many AI or algorithmic computers even. Pattern recognition revolves around uses minimal input to form a complete picture. That\u2019s also how we read, you don\u2019t actively read every word once you\u2019re used to reading. Your brain infers the meaning of a sentence based on a number of keywords and its experience in reading similar sentences. After \u2018the\u2019 you get an adjective or a substantive so no need to read the second \u2018the\u2019. Our visual or olfactory system work in exactly the same way. You exclude long-term input (your nose is always in your line of sight), but are very susceptible to short-term changes (sudden movement).", "Because when you read the the sentence, your brain creates the sentence in your head first and then breaks down the meaning as a whole not just the individual words. So your brain just ignores it because it already has a sentence so ignores the other the.", "Does this have anything to do with the fact that our eyes only senses a small part of reality while our brains fill in the rest of the world? There\u2019s a notion in Sleight of Hand where a good performer can \u201cfeel\u201d where all the eyes are and exploit it by forcing the audience to follow the big movements while hiding the smaller ones. It\u2019s supposed to be based on old hunting/tracking skills. We track where a ball drilled across a football field goes by hopping from where the ball is to where the ball is going easily but once it hits the ground and goes bouncing, it\u2019s easy to lose where it went. You can all think about the difference between a bunny making a beeline to one quickly changing direction. URL_1 Also should be noted that Apollo Robbins is unreal - seen his lecture a few times. URL_0"], "text_urls": [[], [], [], [], [], [], [], [], [], [], [], ["https://www.sciencedaily.com/releases/2014/06/140627094551.htm", "https://www.frontiersin.org/articles/10.3389/fnhum.2011.00133/full"]], "score": [18103, 612, 348, 79, 64, 25, 23, 6, 5, 4, 3, 3]}}]
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