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82di0a | What causes your stomach to rumble? | Repost | explainlikeimfive | {
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"Recently I read somewhere that your stomach always makes those sounds as it’s doing its thing. However, food muffles the noises so you don’t hear them when you’re full. Rumbling when you’re not hungry seems to occur when your stomach is upset. I’m guessing extra gas in the stomach produced at that time makes it more noticeable."
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82eb1j | 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? | Repost | explainlikeimfive | {
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"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."
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82ef22 | Why does it feel like you are skipping through time when you fall asleep? | Repost | explainlikeimfive | {
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"Because you're unconscious, so it's easier for your brain to lose track / not keep account of time"
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82hyyc | How come animals can drink from any water source(excluding salt water obviously) while we can’t drink it unless we purify most of the contaminants? | Repost | explainlikeimfive | {
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"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."
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82jj87 | How do we know what the sun is made of and how much of each element makes it up? | Repost | explainlikeimfive | {
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"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."
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82jrl4 | Why does blood not rush to our feet, like it does to our head when we’re upside down. | Repost | explainlikeimfive | {
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"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."
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82qfeb | Braille vs Raised letter for signage? | 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? | Repost | explainlikeimfive | {
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"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."
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82vya8 | Why snow is white ? | Repost | explainlikeimfive | {
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"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’s 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 )"
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82zx0r | Why the shower curtain gets sucked in to the shower when the hot water is turned on? | Repost | explainlikeimfive | {
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"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_)"
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831g45 | Why does squinting partially improve vision? | Repost | explainlikeimfive | {
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"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."
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837hjb | Torrenting. How do small files come from big files, and what is seeding and leeching? | Repost | explainlikeimfive | {
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"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"
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839k8z | Why does a word start to sound foreign the more you repeat it over and over out loud? | Repost | explainlikeimfive | {
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"“Semantic satiation” 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."
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83bugm | What does it mean when the ingredients of a food product say “natural flavors” ? | Repost | explainlikeimfive | {
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"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..."
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83fk38 | Why is it that you hear about so many new amazing materials / inventions but you rarely see them being used or sold? | Repost | explainlikeimfive | {
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"A lot of the time these inventions or new “breakthroughs” are sensationalized before they ever even get adequate testing. It’s not uncommon for articles to report on something and make it sound like it’s amazing when in reality scientists/organizations haven’t even tested the stuff enough to definitively say whether or not it’s actually useful/not dangerous/worth anyone’s 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’s 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"
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83fo9u | Why are energy drinks bad for you? | Repost | explainlikeimfive | {
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"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 )"
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83irvj | Why do Cars have an odometer that goes to 160 Mph when the max speed limit is 70? | Repost | explainlikeimfive | {
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"The odometer doesn't go to 160 it goes to 999,999. The speedometer may go to 160 that's because people speed."
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83jju4 | Why can time be dilated or compressed but never go backwards? | Repost | explainlikeimfive | {
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"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."
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83mujf | Why is it so hard to make emulators? And why do they work with some games and not others? | Repost | explainlikeimfive | {
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"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."
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83vnfo | How did Old/Ancient Cartographers Produce Fairly Accurate Maps? | Repost | explainlikeimfive | {
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"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."
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83vtoi | What's the difference between a sociopath and a psychopath? | Repost | explainlikeimfive | {
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"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."
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83wlr0 | Why is giving birth seemingly so much more painful for humans than any other animal? | Repost | explainlikeimfive | {
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"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†. 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. †first 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’s 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’s 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."
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83yhc3 | What is the function of a fever when we are sick, and how do anti-fever medications reduce it? | Repost | explainlikeimfive | {
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"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 ¯\\_(ツ)_/¯"
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842qmc | Why do pigeons (and other birds) move their head back and forth on every step they take? | Repost | explainlikeimfive | {
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"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 ))"
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843pu2 | Why were pre-historic animals so much larger than our modern day ones? | Repost | explainlikeimfive | {
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"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."
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84548b | Why are tech and thought leaders so worried about A.I.? | Repost | explainlikeimfive | {
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"The problem is so large that I’m not sure I could boil it down to something digestible by a 5 year old. But here’s 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’s 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 “Where would Einstein be on this graph?” You might think “much higher than the human average!” 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’s intelligence goes beyond us on an exponential scale, you can more or less forget about trying to outsmart it. I’m 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’s 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’s called “The Terminator”. 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."
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845hih | 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. | Repost | explainlikeimfive | {
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"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."
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8461j1 | When houses creak at night, what are those actual noises? | Repost | explainlikeimfive | {
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"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."
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84639g | What happens to a company after it files for Bankruptcy? | Repost | explainlikeimfive | {
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"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."
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846bml | Why is our limited supply of freshwater considered such a global issue when it's possible to desalinate sea water? | Repost | explainlikeimfive | {
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"text": [
"Desalination is energy intensive, expensive, and moving it across large distances to landlocked areas is also difficult."
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84a0ml | What is a wormhole? | Repost | explainlikeimfive | {
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"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 “somebody”. 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’t 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."
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84acql | Why does smoking tobacco cause cancer, but smoking marijuana does not? | Repost | explainlikeimfive | {
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"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"
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84c5jv | how is the mass of distant stars calculated? | Repost | explainlikeimfive | {
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"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."
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84ch7b | . Why does orange juice taste so bad after brushing your teeth or eating something minty? | Repost | explainlikeimfive | {
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"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 — 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 )"
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84d14z | What's the difference between multi-level marketing and pyramid schemes? | Repost | explainlikeimfive | {
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"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."
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84dw77 | What is Grey matter of our brain? | Repost | explainlikeimfive | {
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"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"
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84e3vq | Why does a group of people singing sound better than an individual singing ? | Repost | explainlikeimfive | {
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"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."
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84j06f | How do you add color to black and white photos from say the early 20th century? | Repost | explainlikeimfive | {
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"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."
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84j8cs | How come when you speed up sound it comes out really squeaky, but when you slow it down, it sounds very deep? | Repost | explainlikeimfive | {
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"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’t 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’s 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 ‘la’s 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."
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84j8vq | What even is wind? | Repost | explainlikeimfive | {
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"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."
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84jmio | Fourth Dimension | Repost | explainlikeimfive | {
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"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."
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84knvl | Why do you drift off when engaging in some activity but can't fall asleep when you decide to go to bed? | Repost | explainlikeimfive | {
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"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."
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84pp63 | 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? | There is this light along my stairs which can be affected by both switches without intervention. (AKA no "OR" gates) How is this possible? | Repost | explainlikeimfive | {
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"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 )"
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84t7g6 | How does the body generate heat? | Repost | explainlikeimfive | {
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"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."
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84v154 | Why does glass look green/ opaque if you look at it through its edge? Why does occur when multiple panes of glass overlap too? | Repost | explainlikeimfive | {
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"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"
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84vk82 | Why do soft baked goods go hard when they get stale, and hard baked goods go soft when they're stale? | Repost | explainlikeimfive | {
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"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."
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"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/"
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850xfq | Why does the current go in the opposite direction as the flow of electrons? | Repost | explainlikeimfive | {
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"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"
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850xqy | Why does turning something off and on again fix the problem? | Repost | explainlikeimfive | {
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"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."
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853fz1 | why do you get tired after sleeping alot | Repost | explainlikeimfive | {
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"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’s 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’s doesn’t need melatonin but the brain thinks it does. So there is an irregularity. In this case you feel tired yet not sleepy. Basically it’s 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 “soggy” for lack of a better term, which makes you feel tired or groggy instead of refreshed and awake."
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853y9l | What does “meta” mean? | Repost | explainlikeimfive | {
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"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."
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854wp6 | How do eyelashes know when to stop growing? | Repost | explainlikeimfive | {
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"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."
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8552zo | Why does pushing the button harder on a remote control with low batteries sometimes make it work? | Repost | explainlikeimfive | {
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"dvv0gck"
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"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."
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856k4t | Do stop lights at an intersection actually have sensors if so how do they work? | Repost | explainlikeimfive | {
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"text": [
"Many though not all do. Generally it is a metal or mass detector embedded in the pavement. Often these aren’t 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."
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85dw6h | Why are there no stars in photos of Earth from space? | Repost | explainlikeimfive | {
"a_id": [
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"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!"
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85hs3f | Why does concrete appear to be darker in colour when there is water on it? | Repost | explainlikeimfive | {
"a_id": [
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"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."
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85k5ct | Why do all gas stations in the USA the report the price of gas with 9/10 of the cent at the end? | Repost | explainlikeimfive | {
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"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."
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85nq9i | Why are wet things more transparent? | Repost | explainlikeimfive | {
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"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."
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|
85oe30 | Why does salt harm slugs and snails? | Repost | explainlikeimfive | {
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"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."
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85qc14 | How does a motherboard function / how does it power the cpu and gpu? | Repost | explainlikeimfive | {
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"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."
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85tcu1 | Why is our stomach "in knots" when we are stressed out or worried? | Repost | explainlikeimfive | {
"a_id": [
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"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."
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85umyo | What makes a degree from MIT or Harvard different from the same degree at any other college? | Repost | explainlikeimfive | {
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"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."
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85zhm1 | Does every car in existence have a different key and how do manufacturers make sure keys are not duplicated ? | Repost | explainlikeimfive | {
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"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_)"
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"https://www.reddit.com/r/explainlikeimfive/comments/2j3gpc/eli5_how_do_padlock_companies_make_so_many_locks/",
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"https://www.reddit.com/r/explainlikeimfive/comments/3omzyv/eli5_if_every_lock_is_unique_and_requires_a/",
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"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/",
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"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/"
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861axp | how does sunscreen work? | Repost | explainlikeimfive | {
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"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."
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862owb | / Why does hot food smell more than cold food? | Repost | explainlikeimfive | {
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"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."
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863me7 | Why do men bald, but women don’t? | Repost | explainlikeimfive | {
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"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."
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8683si | why doesn’t tin foil get hot in the oven? | Repost | explainlikeimfive | {
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"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."
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868j4p | Why does excessive heat creates problems during takeoff of airplanes? | 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? | Repost | explainlikeimfive | {
"a_id": [
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"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."
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86bh63 | Flossing, why do it if I brush and use mouthwash, any risks? | Repost | explainlikeimfive | {
"a_id": [
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"dw3vb6n",
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"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."
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86bjjg | Why does licking or otherwise wetting your lips cause them to be more chapped/dry? | Repost | explainlikeimfive | {
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"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."
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86ch7f | How do laser guided missiles work? | Repost | explainlikeimfive | {
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"dw3yf1t"
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"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."
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86evhl | What makes something a good conductor of electricity and how does electricity move through objects? | Repost | explainlikeimfive | {
"a_id": [
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"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."
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86k3zs | How is radiotion, a carcinogenic, is used in cancer treatment? | Repost | explainlikeimfive | {
"a_id": [
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"dw5n1lr",
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"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."
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86ll4g | What makes our ears feel "popped"? | Repost | explainlikeimfive | {
"a_id": [
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"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."
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86mv7v | Why is it so easy to get sick at cold weather ? | Repost | explainlikeimfive | {
"a_id": [
"dw69k44"
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"text": [
"Various reasons: in winter we’re more likely to be indoors, close together, where infections spread easier In winter we also have less vitamin D. Vitamin D aids the body’s immune system. Also, whilst it may not seem like it, the air is dryer, this allows virus’ to flourish."
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86nyvj | What does net worth of somebody means? | Repost | explainlikeimfive | {
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"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."
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86o0i7 | How does carbon dating work? | Repost | explainlikeimfive | {
"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)"
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86unn5 | 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? | Repost | explainlikeimfive | {
"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’t 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’s 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 “smarter everyday” did one or two videos about gloves that can make you feel stuff without actually touching them... but it’s pretty basic compared to what we can actually feel with our skin like softness and so on"
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86xi56 | Why are the planets in our solar system in the same vertical plane? | Repost | explainlikeimfive | {
"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"
],
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|
86y9ky | How do birth control pills prevent pregnancy? | Repost | explainlikeimfive | {
"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."
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86ybgs | While I was microwaving something, I "smelled" that it was still cold; on taste test, it was indeed still cold. How does that work? | Repost | explainlikeimfive | {
"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."
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86yf2v | If the primary colors are red, yellow, and blue, why are TV screens in red, green, and blue (RGB)? | Repost | explainlikeimfive | {
"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"
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86zk6u | why are some sounds in the English language spelt the same but pronounced differently? | Repost | explainlikeimfive | {
"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."
],
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870aeo | Why do oranges have / grow a smaller orange inside of them. | I just ate an orange and was wondering why. Is it normal? | Repost | explainlikeimfive | {
"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"
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870d5g | How did the Nintendo game Duck Hunt know where you were aiming the gun? | Repost | explainlikeimfive | {
"a_id": [
"dw97p3v",
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"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’t 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."
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|
870lum | why do cables/wires tangle when you leave them? | Repost | explainlikeimfive | {
"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."
],
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|
872gq5 | How does “looking up at the sun” help make us sneeze? | Repost | explainlikeimfive | {
"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"
],
"score": [
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"text_urls": [
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"https://en.m.wikipedia.org/wiki/Photic_sneeze_reflex"
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|
8743g6 | Why are gas stations allowed to chard fractions of a cent? | Repost | explainlikeimfive | {
"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)."
],
"score": [
4
],
"text_urls": [
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|
874ee7 | How debt between countries works | Repost | explainlikeimfive | {
"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."
],
"score": [
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|
876dgd | Why do humans get that orgasmic sensation when they clean their ears with a q-tip? | Repost | explainlikeimfive | {
"a_id": [
"dwalugq"
],
"text": [
"You have a ton of nerve endings in there. It’s similar to scratching an itch in that regard."
],
"score": [
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"text_urls": [
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|
877qzw | What do producers and production companies actually do? | Repost | explainlikeimfive | {
"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."
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|
87fakx | How stainless steel soap bars work to remove garlic/fish smells | Repost | explainlikeimfive | {
"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_)"
],
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"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/"
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} | [
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|
87r79u | Why do bigger explosives form a "mushroom cloud" when they go off? | Repost | explainlikeimfive | {
"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."
],
"score": [
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|
87vbnk | Why do scientists try to find oxygen to find life on other planets? Aren´t other forms of life-based on other chemical elements possible? | Repost | explainlikeimfive | {
"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."
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|
885j1w | . Why don’t buildings suffer from water damage and/or mold when it rains while they are being built? | Repost | explainlikeimfive | {
"a_id": [
"dwi63co"
],
"text": [
"They usually crank the heat up to around 100°f and use large dehumidifiers once the building is weather tight to \"cook\" out any moisture. Sometimes even after this mold can still form."
],
"score": [
11
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"text_urls": [
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|
886az4 | What's the difference between brown eggs and white eggs? | Repost | explainlikeimfive | {
"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’s actually blue and speckled chicken eggs as well."
],
"score": [
4
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"text_urls": [
[
"https://m.huffpost.com/us/entry/1342583"
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|
88img9 | 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? | Repost | explainlikeimfive | {
"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."
],
"score": [
21
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"text_urls": [
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|
88j5t8 | Why are so few naturally occurring foods truely blue? | Repost | explainlikeimfive | {
"a_id": [
"dwkz02d",
"dwkz0cj",
"dwl4q8u",
"dwl5bl8"
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"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??"
],
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|
895b14 | Why do we have fingerprints? | Repost | explainlikeimfive | {
"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."
],
"score": [
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89rmq6 | Why do computer applications sometimes freeze up to the point where you can't even click within or exit the application? | Repost | explainlikeimfive | {
"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’t 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’re a lot faster, they actually do one thing at a time. It just happens to go so fast it looks like they’re doing it at the same time. Now, continuing with our human example, when you’re writing your sentences, what if you don’t 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’t figure out how to spell it, or don’t own another pencil, you’re 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’s a good program, it has pre-built alternatives that don’t stop it from accomplishing its task. If it’s a poorly written program, or something goes extremely wrong, the program, or the computer entirely will stop because it doesn’t know what to do. This is what causes computers or programs to freeze, or crash."
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89smur | Why can an ant fall from a distance and not be injured while we can't? | Repost | explainlikeimfive | {
"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_)"
],
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"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/"
]
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|
8aavb0 | How do tv and radio stations figure out how many viewers/ listeners they have? When recording show on a DVR, does that count? | Repost | explainlikeimfive | {
"a_id": [
"dwxa3xd",
"dwx77tc",
"dwxbl28"
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"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)."
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