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5nzohm | how HDD and flash drives store data without being connected to electricity . | i always took it for granted but never knew how it works , can someone eli5 how the data is kept in harddisk drives ,etc... after its not connected to a power source ? | Technology | explainlikeimfive | {
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"Differently. HDDs store data in the polarization of a thin magnetic media. The coding is along the lines of if NS then that's a 0 and SN is a 1. Flash storage uses electrons stored in a tiny capacitor. Lots of charge = 1 and no charge = 0."
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5nzp0s | Why do car manufacturers put out such futuristic looking cars at auto shows, knowing that they would never put those cars into production? | Other | explainlikeimfive | {
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"The same reason high end runways have outfits no one would wear in everyday life. It's a form of art and expression.",
"To generate hype. S'Why cars like the latest Ford GT exist. They're called Halo Cars. Ford even has a legitimate racecar company build them for them instead of building them themselves. Other cars like Audi R8s qualify under this even though they meet serious production. It still makes more people want lesser Audis too. \"Wow! Lookit what Audi can do!\""
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5nzwoc | Why does water make whisky taste different? | I've recently started drinking whisky on the more premium end of the spectrum, and I've been told that many of them benefit from added water. I've found that even a few drops alter the taste completely, but don't understand why this happens as the dilution is so minor. | Chemistry | explainlikeimfive | {
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"Whisky has many in depth flavors that are hard to distinguish when it's \"whole\". When you add water to whisky it's called \"opening it up\" which is diluting the layers of flavor so you can taste each more clearly therefore changing the flavor."
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5o00eg | Why does vanilla taste delicious in food but disgusting when you try it straight up? | Chemistry | explainlikeimfive | {
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"Depends what form of vanilla you're trying. If you're trying \"vanilla extract\" from a bottle, it is in fact a solution of either natural vanilla extract, or maybe artificial vanillin, that is dissolved in ethanol and water. Ethanol is a bit nasty.",
"many things taste good when diluted (peppermint, wasabi, cinnamon oil) but are horrible at full strength. The tongue likes to taste, not get assaulted."
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5o04k2 | How can your body (40, 50 or 60 years later) "remember" that you are immune to virus like chickenpox? | Biology | explainlikeimfive | {
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"When a virus is introduced to your body (think of each specific virus as a lock, and only one key can open that lock to make it safe) your body recognizes that it is dangerous so it starts to make antibodies (the keys to the locks) naturally... but the very first time the virus is in your system your body has to figure out what antibody or \"key\" to use to \"unlock\" or remove the virus.... this is why vaccinations are important because certain viruses work very quickly and by the time your body figures out which antibody to produce the virus could have already spread to other areas in your body and the antibodies would be too late... The antibodies have a certain \"storage station\" of all the different kinds of keys it's already made to crack that certain kind of lock (virus) so once you've already cracked the virus and survived, the next time it shows up in your system it will immediately be taken care of because the key has already been made and your body doesn't need to search for what could work for that virus... Vaccines are weak \"locks\" of the specific virus, that your system can take time to figure out what kind of \"key\" will work on it. So when the dangerous real virus shows up, you will already have the antibody to fight it with. Hope i helped",
"Note: Your immunity can actually decay and even disappear over a very long time span. This is because the population of immune \"memory\" cells for a particular disease (pathogen) can decrease over time as they die off due to naturally aging processes. There are a lot of factors that make different immune responses different--some longer lasting than others. This is why some vaccinations/immunizations require \"booster\" shots. ELI5 immune system: Before you are born your immune system (by shuffling around some genes) tries to make itself a \"library\" of every random shape it can--this library is made up of B cells and T cells. Each cell recognizes one particular shape. Then, the body checks the library of shapes against the all the shapes it can find in your body that are normally there (\"self-shapes\"). Then it removes all those shapes from the library (kills off any early B or T cells that react to self-shapes). Then, it circulates that library of shapes all around the body (B and T cells circulate around the blood and lymph tissues, etc). If one of those cells ever encounters a pathogen (like a bacteria or virus), it begins to multiply rapidly, producing lots of identical cells, then attacks the infection. After it conquers the infection, it keeps a larger population of memory cells around, because it now knows that that particular shape belongs to a real pathogen--and these memory cells can start up again much faster than the original library cells. So early on, that library was based on the immune system using randomness to try and generate as many shapes as possible, and it only keeps a few copies of each shape-recognizing cell around, because it isn't sure if it will ever actually recognize that shape, and it is expensive (and takes up too much space) to keep lots of copies of each one. But once it knows that a particular shape is bad, it spends more energy, etc to keep up surveillance for that shape in the future. This may be more like ELI8-10, but I tried to keep it simple. Edit: this is actually only a description of one branch of your immune system, called the adaptive immune system, which is responsible for immunity to specific pathogens--like the kind of immunity in the question. There is another branch, called the innate immune system, which is more generalized and doesn't have the same kind of \"memory.\""
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5o050c | Why can some people not pee when someone is talking to them or looking at them | Title says it all. A friend of mine can't even pee when someone is near them. Also for clarification when the "tank is full" | Biology | explainlikeimfive | {
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"I got arrested once. On my first night there I was in a cell with this super weird dude. Didn't say a word for the entire time, just sat there reading a book or whatever making me extremely uncomfortable. Well eventually.. My bladder needed to be relieved. Since there was only one toilet in a 9x5 cell I was not exactly happy about having to pull out my penis within close proximity of this random stranger who got arrested for who knows what. So I did what any other extremely anxious person would do... I held it. For hours. But eventually the inevitable happens, I HAD to piss, so I made my way down from the top bunk, walked in front of the toilet, pulled out my dick... And tried to urinate.. But after standing there for about 15 seconds I realized I could NOT piss.. No matter how hard I pushed it just would not come out, keep in mind this is by far the worst I've had to go in my entire life. But I just could NOT do it in front of a stranger.",
"It's primarily psychological. It takes some level of concentration and relaxation, but often people are distracted by other things going on near them and are unable to go right away because of it. There is also the stigma about those who are unable to use the restroom when others are close by should be embarrassed. The idea of not being able to go and becoming fixated on it actually can prevent or delay it because it essentially creates stress that one will \"underperform.\" This would be similar to being unable to become aroused due to fear of underwhelming or disappointing one's sexual partner."
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5o074n | How is it possible for a diet soda to have zero calories? | Chemistry | explainlikeimfive | {
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"Because the legal definition of zero calories and the scientific definition of zero calories are two different things. Diet Soda does not (scientifically) have zero calories but they have close enough to zero calories that they are legally allowed to round this amount down and say they have zero.",
"Look at the ingredients. Water - no calories. Sweetener - very very very few calories. Very small amounts of colourings, flavourings, and preservatives. None of these things can be broken down by the body to make energy, so no calories."
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5o0h3q | How does the sum of the in infinite arithmetic sequence "1+2+3+4..." equal -1/12? | Mathematics | explainlikeimfive | {
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"I'll throw my input in here in case you don't get an answer from a more qualified person (I have a bachelor's in Math, which isn't much compared to high level mathematics). The simple answer is that the infinite series 1+2+3+4... does *not* equal (or \"converge to\") the value of -1/12 in the conventional sense. In fact, this summation actually diverges to +INF. However, there are some adavanced numerical methods which \"assign\" -1/12 to this divergent series (which is different than being equal to). Unfortunately, I have inadequate knowledge to speak about this. TLDR; the series 1+2+3+4... doesn't \"equal\" -1/12, except in a very special case that has very special applications.",
"[Numberphile]( URL_0 ) S^one =1-1+1-1...= 1/2 S^two =1-2+3-4... 2*S(two) = 1-2+3-4+5... + 1-2+3-4 = 1-1+1-1+1... = 1/2 2*S(two)/2 = S(two) = (1/2)/2 = 1/4 S^two = 1/4 S=1+2+3+4... S - S(two) = 1+2+3+4+5+6... -(1-2+3-4+5-6...) = 0+4+0+8+0+12 = 4*S = 4*(1+2+3+4...) S - S^two = 4*S S^two = 1/4 S - 1/4 = 4*S S - 1/4 = 4*S; subtract S from both sides... -1/4 = 3*S; divide both sides by 3... -1/12 = S S = 1+2+3+4+5... = -1/12"
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5o0n5u | What makes some people run so much faster than others? | If you put two guys with similar builds in a race, what makes one run like Usain Bolt and the other run like a Redditor? Is it mainly just technique, as in something that can be taught? Or is there more to it than that? | Biology | explainlikeimfive | {
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"There are really 3 main factors: genetics, experience, and technique. Genetics is very important Olympic runners generally have perfect lungs and muscles for running, one interesting example is in Jamaica. Jamaicans often have several genes that cause them to be naturally more likely to run faster than average these genes are called: the ACE (angiotensin-converting enzyme), and the ACTN3 (Alpha-actin-3) genes. Also body type (being tall or skinny) is quite important Next the experience portion, this bit is obvious, Working out is essential to being a great runner. The average professional sprinter trains 20 hours each week, and consumes TONS of calories in order to fuel them selves. Usain Bolt ate 5800 calories daily leading up to the olympics and in the months in which he trained which was likely around 25-30 hours each week. In addition to this Usain Bolt is Jamaican giving him a genetic advantage. This also includes respiratory and cardiovascular health Lastly technique, this may not seem important but it can easily give you the leg up you need to win. Posture how high you bring your legs slant relative to the earth arm swing. These are all essential to winning in the major sporting events. Additionally mentality while not the most important thing is still important. Although hilarious this quote from Usain Bolt is an interesting example \"I just imagine all the other runners are big spiders, and then I get super scared\" this causes adrenaline to course through him giving his another boost and reason to run. Also people with better reasons for doing things generally perform better."
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5o0ns9 | Why are advertisement on the Internet that are scams not against the law? | Other | explainlikeimfive | {
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"Nearly all scams *are* against the law, and intentionally advertising an unlawful scam is *also* usually against the law. The problem is discovering, and proving, that it's a scam.",
"Various tricks like VPNs, cloud hosting, TOR, and obscure domain registrations (such as .su, .tk, etc) are used to hide the creator/registerer's identity. Also, its so common and low priority that it's not worth cracking down on.",
"Sometimes scams are profitable even if they are illegal because the benefits outweigh the costs and risks. Some examples: - The famous Nigerian e-mail scams, where someone will contact you saying they need help getting a large fortune out of their country and will gladly share a substantial portion with you if you can give them a little cash to free up the fortune for transfer. - Scammers claiming to be from Microsoft technical support who talk the victim into giving the scammer remote access to the victim's computer. - The tax payment scam where the scammer would claim to be from the US government and convince people into making a payment for a phony tax debt. These scams benefited from the fact that they were victimizing people in foreign countries, and their home countries were less motivated to prosecute. India finally made a huge bust and shut down the main call center behind the tax scam. The scams were illegal, but low-risk and high-profit. Here in the US, fraudster Kevin Trudeau made a fortune selling books making bogus claims about any number of topics, usually about health and medicine, but he kept getting busted and kept on going because the fines he was getting were inconsequential compared to the profits he was making. He finally ended up in jail."
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5o0vip | Why, when you experience pain/discomfort, does your face automatically scrunch up, your brow furrow, your mouth frown, etc? And why does it seem to help with the pain? | Biology | explainlikeimfive | {
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"Its an evolutionary emotional response in the same vein as why we naturally smile. The idea is the your cohorts can see your scrunched brow and your frown, etc, and immediately know you are in pain and take care of you and so on. As for why it lessens the pain: anything that consumes bandwidth to the brain will reduce the number of neurons saying \"ow\". Clench your fist, bob your leg, have a conversation. Its all in your head, ultimately."
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5o0wao | If honey is pure sugar, why is it healthy? | Biology | explainlikeimfive | {
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"It's not, is the simplest answer. Honey is processed liquid sugar and isn't any better than drinking the same calories of mountain dew. It's especially bad for babies as it frequently contains botulism spores. Adults and older children can deal with them but babies will get very sick and possibly die. As far as actual medicinal/health uses, honey is a good antiseptic. The high concentration of sugar causes problems with the way water moves in and out of cells, which kills bacteria. Honey has been used as a makeshift antiseptic for bandages and can also be used as a preservative. Genghis Khan and company would soak severed heads in honey to preserve them. But as far as eating it goes no. Honey is as bad for you as any other high-sugar food.",
"As mentioned already, honey isn't really healthy. Nutritionally, it's just sugar. There are some minor differences, for example honey is better for diabetics than processed sugar. The details of why are more than we need to go over. I think people react more positively to honey for these reasons: (1) Honey occurs naturally. That doesn't make it better for you, but people gravitate to anything that says \"natural\", partially as a purposeful campaign to mislead the public (on the part of the food industry as a whole). (2) Honey has some practical uses, like for treating wounds, and allegedly for treating a sore throat. That doesn't necessarily translate to being \"healthier\" in generally, but again people perceive its \"goodness\" to necessarily mean \"healthier\". (3) Honey is produced in a more environmentally friendly and less corporate way. The refined sugar industry is huge, complete with corporate fat cats, lobbyists, partnerships between companies, and mass production. Meanwhile, honey is a naturally occurring product taken from bees. That's not to say it isn't mass produced, but it's easier to source honey \"locally\" and buy it from a family company. In some places, like British Columbia (Canada), there are laws requiring all honey on store shelves to be produced locally. On top of all that, bees are ABSOLUTELY VITAL to our entire livelihood (by pollinating crops) and their populations have recently been at risk. Beekeepers raise and care for bees, while being at the forefront of researching and understanding them. They also cooperate with family farms by pollinating them. Altogether, I'd say honey is a more ETHICAL choice than refined sugars. But when it comes to nutrition, people are mostly misinterpreting the \"natural\" and ethical features of honey for automatically meaning that its also healthier. The few good things honey does for certain peoples' health helps to maintain this misunderstanding (kind of like how people think that because gluten-free is helpful for people with dietary restrictions, it will necessarily be good for them too).",
"You'd have to ask the people who declare it so. Unfortunately, the word \"healthy\" has been abused so that the definition is completely nebulous. Not only does the definition shift over time (1980: Eggs are killing you. 2017: Eggs are miracle food), but for literally any food or activity that you can find someone describing it as \"healthy\", you can find another group of people who consider it the devil."
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5o11vz | How does the fast inverse square root algorithm work? | Mathematics | explainlikeimfive | {
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"The fast inverse square root algorithm has two main parts: the first \"good guess\" at what the square root is, then a quick process to make it a better guess. For the good initial guess, we want to look at what we are solving. For some x, we want to know what 1/sqrt(x) is equal to. Now, based on math rules, we know that sqrt(x) can also be represented as x^{1/2}, so 1/sqrt(x) = 1/x^{1/2}. Next thing is that, by other math rules, we know that x^{-1/2} = 1/x^{1/2}. And *this* is a number we can work with. Now we are trying to find x^{-1/2} (same number, different way of expressing it). The trick to doing this requires knowing about how floating-point numbers are stored in the computer. Essentially, they are stored in a kind of scientific notation, like how we would write 2.98 * 10^{23} to express big numbers. The only difference is that, since its computers and binary, we get a number more like 1.01101 * 2^{101101} or similar. This is stored as just a string of bits, like 01101101101, and we just set it up so that a constant number of bits means the first part, and the rest mean the exponent. Now, to get x^{-1/2}, we first start by dividing the number by two. A fancy trick to do this in computers is just to shift the bits down, so that the last bit disappears and the left gets a zero added, like so: 01101101101 00110110110 This divides the exponent in half, but also has the unintended consequence of adding a random bit onto the \"left\" of the exponent that should have been part of the other half. This is fixed by a really fancy number, 0x5f3759df. When you take our new value above (call it y) and subtract it from the number above (0x5f3759df - y), a couple of \"magic\" things happen. The bits line up in such a way that A) the exponent half of y goes from positive to negative B) the \"extra bit\" that was pushed in to the exponent gets put back into the other half, and the other half pushes over to make room for it. End result, after doing this, is that we get a rough approximation for x^{-1/2}, or the inverse square root. Now, this explanation has gone on long enough, so I'll just speed through the \"finishing touches.\" There's this algorithm called Newton's Method that, given a good estimate for a function (like 1/sqrt(x)) can make that estimate better. Our fast inverse square root algorithm uses 1 iteration (run through) of the Newton Method to make our first, good guess even better, and then we are done. End result is something really close to the real answer, close enough that we don't really care to spend the CPU time to make it better."
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5o135n | Why do so many books have two to three blank pages at the start? | Other | explainlikeimfive | {
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"Imagine I took a standard piece of paper. I could fold it into 4 pieces, then cut the top and bottom a bit, staple it, and have a small book. This is called a signature. They can be as small as 4 pages, or much larger. A book is typically made up of several signatures. The result is, I can take two 4 page signatures and make an 8 page book, but I have no way to make a 9 page book. If I add one page, I have no way to attach it. You can imagine if I stick the page in and just glue the end, it will easily fall out. I might be forced to make it fit in a 7 page book, or maybe print a 12 page book with some blank pages (some print methods can use 2 page signatures). The short answer is that when making books its usually easiest to make them a certain way, and blank pages may be the result. A children's book might be 30 pages, but the publisher finds that one 32 page signature is the cheapest method of production. So they might add something to the pages, or maybe they leave them blank.",
"Books are assembled in groups of pages called signatures. To make signatures even, or to fit a prescribed size, pages are sometimes added at front or back.",
"Different reason depending upon if the book is machine or hand bound. I'll mention the handbound reason, which is the original reason for having these blank pages. The opening blank pages are called fly leaves. The pages with writing/art is called the textblock. These pages, if loaded with art (illuminated) sometimes took days to create. The \"pages\" were vellum (calf skin) and as you can imagine were expensive to make. You want to protect this investment. When books were bound in leather, the tanned leathers would leak and damage the textblock, so the fly leaves were to protect the writing/art from damage. You would use the minimum amount to protect the text block because vellum was expensive to produce. With the advent of fiber paper, you could increase the number of fly leaves. Depending upon on the binding technique used there would a different number of these fly papers. Also, fly leaves are constructed to add structural strength to the book. A book opens and closes and making the hinge strong and durable are important, especially when you consider a town would save up just to buy one book. So there are numerous different construction methods in hand binding that is reflected on the type and number of fly leaves.",
"Publishers prefer to use 16-page signatures because it is the most cost effective. 8 will do in a pinch if necessary. Designers do their best to spread out the text, and the marketing department will sometimes place an ad or two in the back of books with a lot of extra pages. Sometimes you just see the word \"notes\" printed on them like they did it intentionally.",
"Just to add on: When designing a book and you know it will need an extra page or three to print on signatures, you have choices about where those pages will appear. Putting a couple in the beginning is a traditional way to \"open the curtain\" on the book's content, providing a sense of anticipation and signaling a transition from the outside world to the world within the pages.",
"They are called flyleafs. Good explanation of them : URL_0 Tldr: to protect the pages, the binder, write dedications/signatures.",
"I've got a buddy who is an expert. Let me give them a call and see if they can come down here and we will see what it is worth. u/RebeccaRomney can you answer this in only the way you could? ^^^I ^^^wish ^^^that ^^^wasn't ^^^a ^^^dead ^^^account",
"It's probably here somewhere, but I can't find it: Yes. Signatures in manufacturing are obviously the right answer, however in speaking to one of the reasons they leave them blank rather than putting something cool, consider they're leaving you room to sign it over to someone, or write some notes in it. Beyond the fact that it saves ink.",
"Basically, it's a very easy explanation: Hardcover-books have at the beginning and at the end the so called Front-/Endpapers. They don't really belong to the content of the book, but you need them for the book binding. So you have the book cover here. The book cover get's completely glued onto the first and onto the last page of the book. The problem now is, that you need for this a very stable paper. The Front-/Endpapers normally are around 120gsm paperweight, where the content paper of a normal textbook is between 60 - 90gsm. So if you glue it directly to the content paper it will not look nice, you will get wrinkles because of the humidity of the glue,... And that's where the Front-/Endpapers come in place. They get used as the first and last signature in the book and have a higher paperweight. This gives the book more stability. They are glued onto the book block as 4-page-signature to form a hinge to open up the book later. Now why are they empty? Because printing on them costs money. And when the publisher doesn't have something special to out there (like a map, or a registration code,...) they just don't do it to save money.",
"Those used to be there, and often still are, because the book is printed by folding larger printed sheets into the book format, then glue that together at one side, then cut open the other side. It used to be, that you needed to cut them yourself after buying the book. Also, you would buy this folded paper parcel, and then go to a book binder, select a cover you wanted, and have it wrapped in that book cover. The additional pages in the front and back where then a feature to protect the paper stack until a book cover is on it, e.g. on your way to the binder."
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5o17l0 | I baked cookies today. When dunking them hot out of the oven, any pieces that broke off sank to the bottom of my cup of milk. But later, after they'd cooled, pieces that broke off floated. Why do hot cookies sink and room-temp cookies float? | Other | explainlikeimfive | {
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"I know nothing about physics, but I have read a lot about baking. When coating a cake with a flavoured syrup that you want to sink into the crumb, I've read that it works best if the cake and syrup are different temperatures - either a still-hot cake with room-temperature syrup, or a cooled cake with heated syrup. I haven't been able to find any proof or spelled-out scientific explanation, but perhaps the hot cookies are drawing in the cold milk faster than the cooled cookies would? Have you ever noticed how when you pour water on soil that is completely parched, a lot of it runs right out the bottom of the pot without seeming to wet the soil at all (I kill a lot of plants...)? But soil that's only a little dry will suck up water like a sponge. I don't know the reason for that either, but maybe it has something to do with things shrinking as they dry out so the openings water could seep into are narrower. Maybe also a similar effect? I would have thought pockets of steam within the crumb of the cookie would make it more buoyant, not less, but maybe the steam is also keeping those little pores open? Cold cookies are definitely more dense than ones fresh out of the oven (you can see them shrink as they cool), so better moisture-resistance is the only thing I can come up with that would explain the floating. I'd be very interested to hear corrections from anyone with some real physics knowledge.",
"Complete shot in the dark here. Hot cookies are still moist, while cold cookies are dry? A dry cookie has cavities containing air that are hard to reach by milk, and thus float. My guess is that if you cool down your cookies in a humid environment, they would not float. And be all mushy... But that is pure speculation. I have difficulty running experiments that require to patiently wait for cookies to cool down. :-)"
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5o17pu | Why do we pay property taxes if we own the house? | Yeah so a random question just popped up in my head today. Why do we pay property taxes if we own the house? | Economics | explainlikeimfive | {
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"Because the city needs to pay for things that all home owners benefit from such as road maintenance, maintenance of public parks/recreation areas, fixing and maintaining the sewer and water treatment system, paying the police to come to your house if it gets broken into, paying the fire department to come help you out if it's on fire, snow removal if you live somewhere that it snows a lot, street cleaning, part of the cost of running the schools you send your kids to if you have any, etc. Property taxes are a way for home owners in a city to share the cost of these types of public services that they all expect."
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5o19ey | How does noise canceling work, and can it hurt your hearing by actually adding more sounds and decibels to your ears? | Technology | explainlikeimfive | {
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"A sound wave can be represented by the lower image for simplicity: URL_0 Noise-cancelling equipment is able to produce a sound that creates a 'peak' where the heard wave is a valley, and a 'valley' where the heard wave is a peak, as in this diagram (ignore titles) URL_1 This results in no sound being heard, because waves that are perfectly out of phase will cancel themselves. Noise cancelling equipment eliminates droning white noise, not loud noise. The sound itself wouldn't damage your ears, and neither will the equipment that can cancel the sound. Only loud sounds can hurt your ears, so wear ear protection where there is loud white noise, not noise-cancelling equipment",
"The other responders explained the first part of your question better than I could, so I'll defer to them. I'd like to address the second half about whether or not adding more sounds and decibels can hurt your hearing. While active noise canceling headphones add sound waves, they do not increase decibels to your ears. In fact, they decrease them. Think of sound waves like ripples in a pool or pond. The height of the waves (amplitude) is how loud the sound waves are. So if you have something at one end of the pool causing waves 10cm high that might represent a loud sound. Now let's say you have another mechanism that creates waves, but times them in such a way that it adds a peak when the other wave is in a trough and adds a trough when the other wave is a peak. The peaks and troughs of both waves cancel each other out and you get waves with smaller amplitudes. You added waves, but decreased the height of the original wave through interference. This is how noise canceling technology works.",
"Sound waves are sinusoidal. Think of a [sine wave] ( URL_0 ), it varies between a peak and a valley. Noise cancelling produces a sound wave that is exactly the same, but 180 degrees out of phase... meaning at the same time that the original sound produces a peak, the noise cancelling system produces a valley and instead of a valley, it produces a peak. When you combine the two waves that are 180 degrees out of phase, the amplitude cancels out to zero. It's the same as how adding +1 and -1 = 0. Does it hurt your ears? No, because the level of the sound is actually reduced. This isn't tricking you into thinking that it's reduced, it really is. The amplitude of the noise reaching your ear drum is much lower, which is why you don't hear it."
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5o1bq8 | How does the postal service machinery know the correct amount of postage has been put on via stamps? Especially with old postage stamps, or a many small currency stamps. | When I put a stamp on the envelope, how does the machinery know the correct amount / how much postage has been placed on the envelope? Is each stamp micro-printed with a code the machinery can read as the value, or does the machinery have a database of every stamp and it's proper value? And what about small packages with stamps (like books) where there's a total of like 12 stamps between forever stamps and 2 or 3 cent stamps? | Technology | explainlikeimfive | {
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"The usps is very outdated and playing catch up they aren't good at catching it and rely on the workers a lot to catch it . They use to be really terrible and I know people who would ship out dozens of packages daily all at 1 lb no matter what and rarely ever had issues for years . Fedex use to check 10% of packages for accuracy and now I am not positive but it might be 100% of them . Conveyor belts , cameras , sensors , scales barcodes it all gets processed now with lightning speeds at the distribution centers . Watch any Fedex or ups warehouse video or documentary online and you can see how crazy they are . Tons of people still scam the post office all that happens is you get a \" postage due\" notice unless it's on a massive wide scale then maybe they will investigate and prosecute . Fedex and ups just bill you no matter what depending on weight and dimensions ."
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5o1rom | How do resale retail stores (ie. Winners, Homesense etc.) work? | Higher chain retail stores such as Winners claim to have designer labels at better prices. I am wondering how they get their merchandise, and how are they able to sell it at a lower price and still remain successful? | Other | explainlikeimfive | {
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"Where I am, we have resale stores like Marshall's and TJMaxx. What they do is, whatever didn't sell at the big-name department store last year gets bought for cheap by resellers and sold in their stores the following year. The big name stores are all about changing their inventory every year, so whatever they couldn't sell at end-season-clearance, they sell to a reseller to get whatever profit is left. I have actually seen this where I saw a yoga infinity wrap for $50 and I sneered at it, thinking \"Hell no am I paying $50 for that.\" One year later I saw that exact same wrap, same brand name, same color in Marshall's for $10 and I sez to myself, I sez, \"Self! Hell YES am I paying $10 for that!\""
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5o1rrg | why is it ok to watch a sunset, but its not ok to stare at the sun any other time? | Other | explainlikeimfive | {
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"text": [
"When the sun is low on the horizon, it has to shine through more atmosphere to reach you since it's going across instead of straight down. This dims it by absorbing and scattering the light."
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5o1s0x | What is the purpose of tonsils? Many get them removed and the only time I hear of them is when people get tonsillitis | Biology | explainlikeimfive | {
"a_id": [
"dcfz576"
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"They are like repositories for white blood cells, they just sit there and wait for pathogens to try to enter your body through your mouth and then kill them. Tonsillitis is when they get overwhelmed by these pathogens and their reaction to them becomes so extreme that they themselves cause illness, usually chronically."
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5o1um8 | Why is it impossible to decrypt something after it has been encrypted to md5/bcrypt/etc? | Technology | explainlikeimfive | {
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"Because those aren't encrypting functions. They're hashing functions. Unlike an encryption functions, hash functions cause you to lose information when you do the transformation. The simplest operation that exhibits this property is modulo division (taking the remainder of a division operation). If I have 12 mod 5, the answer is 2. But, given just the numbers \"5\" and \"2\", there's no mathematical operation you can perform that will result in you getting 12. Now, modulo is a pretty simple operation, so you can see pretty quickly that the numbers 7, 12, 17, 22, and so on will all match this problem. With the password hashing functions, there's still multiple solutions that will give you the same hash, but the math is complicated enough that the guess-and-check method of trying to find a match for a given number will take centuries."
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5o1uy0 | British lawyers and the British legal system - Prosecutors working for private law firms? | I'm an American who has just started watching the UK TV series "Silk" and it seems I have a lot to learn about the British legal system. As I understand it, barristers are lawyers who work in courtrooms and solicitors are lawyers who work at desks. Is that a fair summary? It also seems that prosecutors are not employed by the state, but instead work for private law firms like defense lawyers. Is this correct? How does the state pick a prosecutor? How does the state decide which law firm will provide prosecutors? Does the state directly employ any prosecutors? It also seems to me that the judges are much more proactive than American judges. In the US if a courtroom lawyer is out of line, it's usually up to the opposing counsel to object, but I seem to see judges scolding lawyers on their own in this series. Is this a difference between inquisitorial and adversarial models? | Other | explainlikeimfive | {
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"English solicitor here! The profession here is split into two branches: solicitors and barristers. The former are generally employed and work for law firms that are independent of the state. They are like any other business in that respect. The solicitors are, like you said, mostly desk based and will prepare cases and interview witnesses etc. Barristers are self-employed and are paid, often via the solicitor, by the case. To cut costs and help with professional development they share premises (like an office) which is called \"chambers\". They mostly spend their time advising on the law and attending Court for trials and the like. I guess they can be likened to a US \"trial lawyer\". In civil law matters (like employment disputes, contractual matters and personal injury), you as the Claimant (what the Plaintiff is now called) will hire a solicitor by approaching a law firm who will, in turn, engage a barrister for you. The Defendant will do the same. But as you are talking about the TV programme Silks, I suspect it is criminal law you are interested in. With crime, the state will be prosecuting you. Here the solicitors are employed by the state in an agency called The Crown Prosecution Service (CPS). They will review the evidence collected by the Police to decide if you should be prosecuted. For minor matters (drink driving, minor assaults) a solicitor from the CPS will attend court to present their case against you. For more complex and serious matters like rape, murder etc., they will engage a barrister (who, remember, is self-employed) to present the case. That barrister will be paid for that matter alone. Now, here is the confusing bit: the barrister will sometimes take cases for the Prosecution one week, and then for a Defendant the next. Some only Prosecute, others only defend. The CPS will select a barrister based on their experience, the area of criminal law, locality, availability and sometimes if they like them. You, as the Defendant, are free to choose from any criminal defense firm of solicitors, much like in civil law. You pick your firm and they will select a barrister for you to defend you. Probably 95% of the firms and the barristers are paid by the State via Legal Aid as Defendants can't afford to pay them themselves, but the firms and barristers are always independent and of the \"same quality\" as if you paid yourself. Other matters from OP's question: The state chooses what firms can defend by way of a Legal Aid contract. Any firm can bid to accept this type of work and if selected is then authorised to do so. There is currently a big debate going on here about how this has forced income down and is just being used to get it as cheap as possible. That's another story. The burden of proof is ALWAYS on the Prosecution. You, as the Defendant, do not have to prove anything at all. Not even your innocence. You can refuse to employ any lawyer, or even give evidence. The Prosecution must show you are guilty beyond reasonable doubt (which these days is if you are \"sure). As a note in civil matters it is, once again, the Claimant who must prove their case, the defendant does not. As for Judges, they manage the Courtroom very well and will clamp down hard on anybody breaking the rules. Objections seem to be very common in the US, but I do feel that this is handled by the Judge here. Finally, we do use the adversarial system here, just like the US, not the inquisitorial system. *note to other lawyers/pedants: yes, I know it's a little more complex than this, but I am on mobile, pushed for time, and wanted to simplify it a bit."
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5o1znd | Would death by extreme heat or extreme cold be objectively more painful and why? | If you were put in a room and could ensure that the temperatures were dialed in to kill you after exactly one hour in both scenarios... | Biology | explainlikeimfive | {
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"Given that both are set to kill you in exactly 1 hour I would say heat. Even immediately after entering that room you would be in pain, and continue to be in pain. Nerve damage would set in, but not fast enough for you not to be in exruciating discomfort for almost the entire time. The only thing that might help is that with consistent, sweltering heat for a full hour, at some point you might become completely delirious from lack of water. And your brain might stop working properly, but there would always be pain. In contrast, lethal cold would numb you at least comparatively quickly. Hypothermia, would slowly shut your body down until your organs fail",
"Are we gonna see OP in the news soon?",
"Extreme heat, most likely. Extreme cold will be bad for a while, but as you approach death you will feel warmer. There are cases of people found dead of cold having stripped off their clothes before death. Extreme heat will most likely continue to cause nerve damage but not total destruction, plus if you ONLY want death and not total charring, then the person will definitely still have nerves intact to feel pain",
"Extreme cold would be less painful. You'll get hypothermia and fall asleep first. Of course it depends on how extreme we're talking."
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5o213b | What are the differences between a condo, townhouse, and apartment? | What classifies a townhouse as a townhouse, condo as a condo, etc? They all seem to have similar qualities/features. | Other | explainlikeimfive | {
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"Condos (aka condominiums) are a form of ownership. There are apartment condos, townhouse condos, and even detached condos. Anyone who describes a condo as similar to an apartment simply hasn't experienced the variety of condos and doesn't understand the legal meaning. All condo means is that you generally just own outright part of the structure (typically just the interior) while you have shared ownership of the rest (exterior walls, roof, land, yards, driveways, etc.). A condo association is essentially the corporation that manages the shared areas and enforces the covenants on the private areas, with each owner being a member of the association. An apartment is a unit in a multistory, multi-family building. Typically each apartment is entirely on one floor but there are fancier duplex apartments, with units extending two stories. Historically apartments had a single owner who rented the units out to different families, but condominium apartments started becoming popular in the last half of the 20th century. A townhouse is a small urban home, usually two or three stories, but single family, and with walls touching the neighbors' walls. Sometimes it will be a single wall between houses, but in such cases there needs to be some legal mechanism to deal with the shared wall. I grew up in an apartment building in NYC that was owned by a real estate company and was strictly rental. Later on, after my parents retired and moved, the entire set of apartment buildings was converted to coops (basically a NYC concept, somewhat similar to condos), with the tenants given first crack at occupying them. In Boston, you can find traditional apartment buildings. You can find buildings that started out as traditional apartment buildings and were converted to condos. Because housing is expensive in Boston, there are many cases of taking a large 3 story Victorian house and converting it into a condo with three units, one on each floor. My brother, out in the Bay Area (Calif.) bought, with friends, a small four unit garden apartment building. (\"Garden apartment\" means a two story apartment building, versus regular apartment buildings which are taller.) They removed the exterior entrances for the upstairs apartments, installed interior staircases, and converted the four rental apartments into two townhouse condominiums. This shows how slippery the definitions can be. But if you remember that condominium is a legal concept, not an architectural one, you'll never go wrong. Edit: typo",
"Not sure if this applies everywhere, but where I live: An apartment is a unit in a building that you rent. You do not buy an apartment. A landlord owns the building and is responsible for its upkeep and generally makes all the decisions for the building and the units. A condo is a unit in a building that you buy. Although, you can rent it from the owner, but generally a person owns a condo. Each person owns their own condo and a group of condo owners in a building have a condo committee that makes decisions for the building democratically. Individual owners can make changes as they please to their own units, within certain limits set by the committee. A townhouse is also a unit in a building that you buy (but again, can be rented from an owner). Townhouses are generally several units joined together in a single row, as opposed to an apartment or condo building which is stacked. Apartment and condo buildings look similar. Townhouses are houses that are connected in rows.",
"In most of the U.S. in standard American English, an apartment means something designed for renters, while condos and townhomes are designed for homeowners. There are exceptions - for example you can rent a condo from that unit's owner. But a large apartment complex probably has a management office, whereas condos and townhomes don't because the residents are the owners and they don't pay rent, so there's no need for a manager. All three are buildings with more than one unit. Apartments and condos are typically 2 or more floors, and quite often units don't have their own \"outside\" entrance, i.e. you have to first enter the building and then enter your own unit. Townhomes are typically made up of 2-or-3-story units that each have their own outside entrance. A townhome is basically just like a house but with no side yards, because one or both sides of your house share a wall with your neighbors.",
"I live in Australia and we don't ever use the term, \"condo\". An apartment is usually a unit in a high rise building. These are usually in the inner city areas although they've started building them in large, mid - outer suburbs. They can be rented or bought and can be residential only or mixed in with commercial offices/retail spaces. They're usually only 1 floor high but double story penthouses isn't uncommon. Most apartments are occupied by groups of uni students, young people and professional couples. Some of them have a balcony and the penthouse might have a larger outdoor space. There's usually a body corp who is paid a fee to maintain shared areas. We also have really ugly, huge government housing known as \"commission flats\" in the inner suburbs. They're technically apartments but I've never heard them referred to as that. They're not places you'd ever want to reside in. A unit is a group of small houses, usually built in a vertical line or a U shape, on a long piece of land. Although they can also be arranged other ways such as in a horizontal line on a wide block or scattered over a large piece of land. They can either be joined together or completely seperate. They usually have a small backyard/courtyard but this isn't always the case. Sometimes they're double/triple story but the individual units are only 1 level. They're usually pretty similar if not identical to each other on the inside and out. Old, cheap units are more likely to be occupied by poor people, young adults, uni students and people on VISA's. They exist everywhere and can be rent controlled, owner occupied or government housing. There's usually a body corp who is paid a fee to maintain shared areas. Subdivided properties are very common here and although they're technically a unit, I see them as being different. Houses were built on large blocks in the suburbs so people now often build a fence in their backyard and build a new dwelling behind the original. They differ from units because they usually have seperate driveways. Families often live in these because they're affordable whilst being bigger than a unit/apartment. They can also be rented or owned and don't usually have a body corp. Townhouses are usually newer, bigger and multy level units that share a wall with at least 1 other house. They often have small backyards, garages and their own driveway. They can be rented or owned and I don't think they have a body corporate. Terrace houses exist in inner city areas. They're very skinny houses that are usually joined to other terraces. They can be single or double frontage and some of them are double/triple story. Theyre usually just a long hallway with rooms coming off one side all the way down. Some have small yards and the majority don't have driveways or garages. Lots of them are hugely run down and rented for rediculous prices to young people and uni students. A lot of them are also heritage listed so you're limited in what you can do to them. There's also a lot that have been renovated/updated and they're amazing but unaffordable for the average person. Estates are all the rage over here at the moment. They're large areas of houses that look the same/similar, they're built by the same company and sold off mostly to new home buyers/young families/retired couples or investors renting them out. They're built quickly and cheaply in outter suburbs, usually when farmland is sold off after being approved for rezoning. The houses are built close together, they often have small yards, the roads are narrow and parking is minimal although most have a garage and driveway. I don't recommend them but I understand their purpose. They usually have a body corp that look after the gardens and make the rules about what you can/can't do to your property. Last but not least, single dwellings are still the most common residential building here. Unlike some areas in America, almost EVERY property has a boundary fence on at least 3 sides (back and sides), with a gate/fence connecting the front and back yards also common. They usually have a driveway and many have a garage or carport. They also typically have a good sized backyard. They're rented/owner occupied by families, couples, uni students, friends etc. If you own the property, you're only restricted by council regulations which differ depending on the area you live in."
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5o27ww | Why do only some people seem to be overly sexual whenever they are drunk? | Chemistry | explainlikeimfive | {
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"Alcohol lowers people's inhibitions/self control. While they might be thinking about it sober, they tend to keep it under control. Alcohol makes it harder to do that. That doesn't necessarily mean they're secretly giant sex fiends- it can be one thing leads to another. For the most part, almost everyone notices sexual cues. But between people there's a lot of things that can vary: how much they notice them sober, how much they drank, how well they convey themselves drunk, what situations they put themselves in drunk, etc."
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5o29l8 | What is dry drowning? | And how can someone dry drown in a pool? | Biology | explainlikeimfive | {
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"From what I can tell, dry drowning isn't \"drowning\" in the sense that water is filling the lungs and gas exchange cannot happen. In dry drowning, inhaling a bit of water can cause the vocal cords to spasm and block the flow of air from the mouth to the lungs. There is also a phenomena called secondary drowning, which can take place up to a day after swimming. If a child inhales some water, or even small amounts of water over time, that water can accumulate in the lungs and cause breathing problems later on."
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5o2bid | why is Taiwan valuable to China under the "One China" policy? They've been ruled separately for so long, what would the real benefit to controlling it again be? | Other | explainlikeimfive | {
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"Taiwan is the legitimate government of China that fled when the communist revolution occurred. Allowing them full autonomy erodes their own legitimacy.",
"Contrary to the other responses, I think economic reasons are pretty much secondary to geopolitics and nationalism. China already has a massive economy. The addition of Taiwan, particularly after the trauma and disruption of a hostile takeover, would not be a decisive boost to the Chinese economy. Nationalism is really big in China, Chinese leaders and media have long emphasized that Taiwan is a rogue province. They have also tended to emphasize national pride and territorial integrity. So the reclamation of Taiwan would be a major propaganda coup for the CCP. Taiwan is also important because it lies right off the Chinese mainland, and is a western ally. Consider why the US were so alarmed when Cuba drew closer to the USSR during the Cold War. But really nationalist chest-thumping is the bigger reason here. This is also why they are so obsessed with those tiny islands in the South Sea, not physical resources."
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5o2btk | Why are cloth items like towels, rags, etc. tougher to tear when wet? | Other | explainlikeimfive | {
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"text": [
"There are a couple of possibilities here. One possibility is that hydrogen bonding in the water increases the strength. Another possibility is that the water causes the fibers in the clothing to swell, increasing the friction between the fibers, and making the fabric harder to tear.",
"URL_0 Fibers are more pliable, think. . . playdough wet vs dry."
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5o2bw3 | What does "±" symbol mean? | Mathematics | explainlikeimfive | {
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"text": [
"It basically means \"plus or minus\". In this context, it looks like they're using it to mean \"approximately\" as in \"give or take a couple years\". Under more typical circumstances though, it would be used to indicate a range. For example, if it said 16±2 years, then it could mean anywhere between 14 and 18 years of education (ranging from 16-2 to 16+2 years). In sciences, the symbol is frequently used to express tolerance or statistical margins of error in measurements (i.e. indicating a range of possible values). In mathematics, it can indicate that a value may result from either an addition or subtraction operation, or that a given value can be either positive or negative."
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5o2cuh | Why do all movies cost the same? | Not only when you go to the movie theaters are movie tickets all the same but DVD releases and streaming are the same prices. Shouldn't capitalism kick in and have the shittier movies be cheaper? | Economics | explainlikeimfive | {
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"text": [
"This is a good question. Firstly, there are tiered cost. My theatre offers standard screenings, 3D and luxury class (this can be standard or 3D but comes with better seating and waiters bringing you cooked meals, desserts and drinks including alcohol, coffee, ice chocolates, etc). Then there are imax theatres, as well as cheaper arthouse theatres. However, this doesn't directly answer your question because each of those tiers still costs the same regardless of which movie is played there. What it DOES mean though, is that there is limited showing and seating capacity per each tier. Regardless of WHAT movie is being seen in each tier, you're still paying for a 'theatre experience' of that tier. This is what is valued, not the movie screening. The movies are simply selected (typically, studios may cut deals and stuff to get their screenings shown, might be rare but can't exclude the possibility) based on their ability to fill the seats in each tier to maximise profit. This is where capitalism and supply/demand takes effect. \"Of all the movies at our disposal, which should be selected for the luxury screenings this week? Which for 3D and other tiers? How many screenings of each?\"",
"Only the movies in demand stay in the theater. If it's a good movie, it will stay, if it's bad it will be replaced quickly. Same with DVDs. The bad movies end up in the bargain bin. The good movies will get special packaging, special editions like Criterion, etc. Streaming is a good question. I've noticed that the premium offerings sometimes are more exclusive to a single provider, while the bad movies are easier to find. They are still both available as part of the monthly fee... but if a provider has bad content overall it won't be able to charge as much. Interesting business model.",
"A lot of this boils down to \"because they can\". Studios release a lot of movies. Streaming services show a lot of movies. It makes no difference to them which one you watch. They don't want to compete with themselves. The only people who might care are the people involved in the movies themselves, and these people have no say in pricing."
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5o2hby | Why does it take ~5 seconds to get yourself to pee? Why isn't it instant? Is this an anti leak mechanism? | Biology | explainlikeimfive | {
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"Human's have two urethral (urinary) sphincters. One of them is under voluntary control, the other is not- it is autonomic. Both have to open for urine to flow. The autonomic sphincter is controlled by the parasympathetic nervous system, which uses more complex chemical signalling (peptides in addition to the normal acetylcholine) to operate. This slows the response time (kind of like the difference between a combination lock and a keyed lock) but does indeed make it more \"leak proof.\" Interestingly, that same autonomic sphincter is believed to be the cause of \"bashful bladder.\""
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5o2ues | Why do most news websites currently have a "Click to expand article"/"Read More" button on mobile? | Technology | explainlikeimfive | {
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"text": [
"Lots of reasons: * It allows the page to load faster in order to get all those ads in. * It validates the interest in the article that justifies the rates charged to advertisers. * Enables the page to fit the horizontal screen of a lap top. * It enables them to switch ads in order to get more advertiser exposure. * Enables the memory required to fit the limited capability of a smart phone. * Enables them to offer an online subscription.",
"Allows them to load more ads before the end of the story So basically they get more ad views before you realise you have to click the read more button.."
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5o2z3s | Why/how do we involuntarily scream when we're scared? | Biology | explainlikeimfive | {
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"text": [
"We talked about this in a Psychology class I took. Supposedly, it's an innate, near-primitive response to fear. It supposedly originated with recognizing a threat to wellbeing and needing to alert our caretakers (usually our parents). Babies do exhibit many characteristic responses that are theorized to have reasons passed down by evolution as well, so I don't doubt it.",
"Because it's coded into your genetics. Since its coded in your genetics, you have a tendency to scream, because the ones that were not naturally seelcted to scream were killed and the ones that were genetically selectd to scream were not and reproduced, evolving the traith of involuntarily screaming when you're scared. it became a defence mechanism that the body developed due to evolutionary pressures caused by the environment, that is the environment had predators or anything that could kill you that would be scared off by any vocalization e.g. a scream and would scare them off, more than it would not scare them if you didn't scream, hence why you would have survived if you screamed. since it was embeded int your genetics, it would be passed onto your kids, but the ones that didn't scream, they would have been killed be predators, and therefore not be passing those genetics into their children. so Tldr; the reason you scream is because its embedded into your genetic algorithm."
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5o32xq | why is it that when a lot of people talk at once, the sound is multiplied to a point where, a stadium full of people talking quietly to one another, can be louder than just two people screaming? | you would expect the volume to remain the same when everyone is speaking in the same decibel | Physics | explainlikeimfive | {
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"text": [
"Sound waves add up, but not in a simple \"X amount of people = X amount louder\". Doubling the audio sources (people talking, speakers, etc.) gets you about 3db louder (assuming same volume from each), you need 10x the amount of audio sources to get ~2x as loud."
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5o3340 | Why is it advisable to block your license plate when sharing a photo of your vehicle? | What can other people do with that information? | Other | explainlikeimfive | {
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"text": [
"License plates can be used to find where the owner of the car lives. Unless you're completely comfortable with random strangers knowing that, it might be a good idea to block the plates."
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5o3e2p | How's it possible to calculate the volume of geometrical bodies ? | Take the normal cylinder for example. In high school, we defined its volume as a product of its base (the area of the circle) and its height. This definition relies on the idea that we can "stack" circles until we reach the height *h*. Since circle is no more than a bunch of dots (points), which don't have depth property, it can be concluded that circle in itself does not have depth. Without depth, there isn't volume. Therefore, how is it possible to calculate the volume of geometrical bodies? Thanks in advance. | Mathematics | explainlikeimfive | {
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"text": [
"You can \"stack\" dots, which don't have length, to get a line, which has length. You can \"stack\" lines, which don't have width, to get a plane, which has length and width. You can \"stack\" planes, which don't have depth, to get a volume, which has length, width and depth."
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5o3ikp | How do companies like Coca-Cola make money from vending machines and sales located in very rural areas in undeveloped countries? | For example, I went to India a few months ago and went to a very rural town. At a small shop with barely a full roof, there was a Coca-Cola fridge selling Coke. How does Coca-Cola make money from this? How does the company the kind of reach where they can bring their products to such local areas where even continuous running clean water is difficult to come by? | Other | explainlikeimfive | {
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"well if its rural that means it'll be hard to find, so stores will want to carry such a coveted product. the store pays coca cola and they profit, now its up to the store to sell it so they themselves can profit. coca cola is very popular and in high demand, it costs practically nothing to make with our super awesome mass production ways.",
"Look at it the other way round - the stuff is as cheap as piss to make, so think HOW MUCH profit is being made in USA",
"I currently live in a undeveloped country.. In this case I will say Kenya. Here I haven't seen not many vending machines. (Infact I can't remember seeing one since I been here). How they make money is actually really different than more modernized countries such as western Europe or US.. They use glass bottles. I know it's crazy. But in fact small shops actually get most of these things for free. Coca-Cola gives them a crate of glass bottles of varieties. (Fanta, Coke, Sprite, etc). When I buy a bottle I pay about 30 shillings (.30 cents USD) and a 20 shilling (.20 cents USD) \"deposit\" basically a little over 50 cents.. After I'm done drinking I return to the same store to get my deposit. I know that 20 shillings isn't that big of deal to walk back to the store to get my money but it's a lot of money for the majority population.. Afterwards. Once they finish the crate they redeem it for cash. They give the cash earned and empty bottles back to Coca-Cola warehouse. Coca-Cola gives them money and they re-use it.. Recycling! Anyway, I'm not familiar with the plastic bottles. This is just a personal experience.. I'll email the rep over here and get a full detailed explanation.."
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5o3iks | Why do we feel guilty after masturbating? | The cycle keeps repeating help. Biologically, after orgasm I feel uninterested and "eh" or a bit guilty. Why is that? | Biology | explainlikeimfive | {
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"I'm trying to find a link to the study I read about it, maybe someone else can help, but here goes. As a person's sexual rush starts to build up steam, all the chemicals in their head start going crazy and often they start getting a greater sexual thrill from the opposite of their conscious, non-sexually-piqued tastes. Think about when you see some sort of scandal in the news where a high-powered businessman gets caught getting involved in some bdsm action- they're normally used to being in full control, so for them they can lose themselves sexually when placed in a position of helplessness, i.e. strapped to a bed whilst a woman whips them. So you're fapping away and getting turned on by stuff that is away from your normal and character and bam, it's time to ride the white wave. As you climax you get that initial sexual rush of chemicals in your head, but then slowly but surely the balance returns to what it normally is. This crosses over, so you go from finding what made you chuck sexy, to how you consciously feel about it, which is usually not that great, and feel guilty for finding that sexually arousing. The people saying 'religion' are both right and wrong. If you were brought up in a religious house, the idea of fapping could be a great turn on because your conscious mind tells you it's wrong, but when you finish your mind is 'clearer and then the guilt creeps in. So that bit is right, but it's not solely down to religion, it's just one part of it. An atheist can feel just as guilty after a fap.",
"There are several theories, but most relate to the \"refactory\" period in male sexuality - the recovery phase after orgasm during which it is physiologically impossible for a man to have additional orgasms due to increase in the penile sensory threshold. After the orgasm, the brain is flooded with hormones, and others ease their effect. The hormonal mental effect is quite strong - some men experience this as guilt, some as profound disinterest in sex, some as relaxation. This feeling ebbs exponentially as the refactory period elapses and is strongest immediately following the orgasm. Its a bit like a crash. EDIT: I would further add that human sexuality is a complex thing, interwoven between psychological, hormonal and biology. There was a recent study showing how sexual feelings overcame feelings of \"disgust\". Its suspected that similar actions are at work: prior to orgasm feelings of guilt and repression add to the sexual arousal. After climax, those repressive hormones aren't at work, and the feelings are more apparent. URL_0"
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5o3j0f | how do 64kb demos work? How is a video generated from such a small file? | Technology | explainlikeimfive | {
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"text": [
"My thesis supervisor was interested in these demos ([here's one he made]( URL_3 ) and [here's]( URL_1 ) his thesis on it, though it's in Czech, but there's a lot of pictures) and he told me a little bit about them. Here are the main things: - The demo in not a video, it is a program that renders the animation. Program is small because it is just a small amount of instructions. - Procedural generation: Data, such as textures, is what takes up absolutely the most space in programs. Here instead of having the data embedded in your program you create algorithms that generate all the data, somehow randomly but within certain rules. Algorithms are extremely small, even if they are complex, because they are in result just a few instructions, of which each only takes a few bytes. These algorithms can however generate huge amount of data - textures, 3D models, music, everything. For example you can generate so called [Perlin noise]( URL_0 ) and use it as a heightmap for terrain. If you're more clever, you can make images like [these] ( URL_2 ) (these are from my bachelor's thesis on procedural textures). - Getting rid of any unnecessary stuff: In normal programs a few extra kilobytes usually do not matter, so most programming tools add extra layers to programs to make the programming more comfortable, faster, safer etc. If you want your program to be small however, you can give up these advantages and save memory. You can do this by using a low level programming language (assembler, C, ...), using special programming styles, telling the compiler you want to optimize for size, giving up platform independence etc. - Some data, such as camera movement, can be embedded in the program since they are very small. Camera movement can consist only of a few keyframes and the program then smoothly moves the camera between them. Camera keyframe may look like this: time (4 bytes) camera position (x,y,z = > 12 bytes), camera rotation (x,y,z = > 12 bytes). This is a total of 28 bytes for each keyframe. If you have 20 keyframes, your whole camera movement is encoded in 0.5 kb. - Compression: to make it even smaller, everything is compressed in the end."
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5o3kcj | What is the difference between being declared clinically dead, and being actually dead? | Biology | explainlikeimfive | {
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"text": [
"There's a big difference between mostly dead and all dead. Mostly dead is slightly alive. With all dead, well, with all dead there's usually only one thing you can do. Go through his clothes and look for loose change."
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5o3mfw | How does MSG make food more flavorful and less importantly, colorful? | Chemistry | explainlikeimfive | {
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"text": [
"TL;dr food chemistry dictates that colourless MSG reacts with sugars in your food to make brown tasty compounds that you associate with savoury \"umami\" tastes and these are delicious. - - - - MSG is just monosodium glutamate, or, the sodium salt of glutamic acid. Glutamic acid is an amino acid, used to build proteins in organisms, so it's perfectly healthy in appropriate doses. Glutamic acid and glutamate are not themselves coloured, and when present as the sodium salt come out as [nice white crystals]( URL_2 ). It isn't coloured because it doesn't absorb any light in the visible range, so it comes out white. The reason a lovely browner colour develops when cooking is because glutamate reacts with sugars in a reaction called the [Maillard Reaction]( URL_1 ). This reaction is responsible for a lot of the tastes when meat is cooked, for example, and involves the reaction of protein breakdown products (amino acids) with carbohydrates and sugars in the food. This [cooking chemistry video]( URL_0 ) runs through the Maillard reaction with a good explanation. So if your food has carbs and you add MSG, you'll get a variety of different flavours as the MSG reacts with the sugar tips of the carbohydrate, and turns the food brown in the process. Each different carb or sugar has a different flavour associated when the Maillard reaction occurs to make different products. Even these break down more and the subsequent heating and follow-on breakdown reactions lead to new food products with diverse flavours. Therefore each food has its own set of flavour carbohydrates, which produce it's distinct taste when cooked. Nota bene: that the Maillard Reaction still occurs with the breakdown of many other proteins and their amino acids (lysine, valine, leucine and many others); so not just glutamate or MSG., The reason glutamate is added as an extra additive probably because it tastes bloody good when you cook stuff with it. Think umami, savoury like flavours.",
"MSG is simply an amino acid salt and works for savory flavor the same way sugar does for sweet and salt does for salty. It is the purified essence of savory. It naturally occurs in huge quantities in things like soy sauce and meat stew.",
"So there are a few basic tastes that we have; salty, sweet, sour, bitter, and umami. Umami is pretty much what we would know as savory (ie meats, cheeses. Now each of the tastes have a corresponding substance that makes you taste them, salt (sodium), sweet (sugar). Now for Umami the taste is derived from glutamate so if you add more glutamate you will taste more savoriness. MSG stands for monosodium glutamate so you can see that there is glutamate in it so adding it to a food will add/enhance the flavor of the dish much like how adding sugar or salt can add/enhance flavor."
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5o3p78 | Why is horse racing such a tossup? | I'm wondering what it is about horse racing that makes it so consistently ideal for gambling. To clarify, I'm not asking why people use horse racing for gambling, that answer is evident (because its never a sure thing). More I'm curious about why it's never a sure thing to begin with. Why is there so much variance to a horse running a short distance in a controlled environment? | Other | explainlikeimfive | {
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"They are set up that way. Track stewards assign weights to horses to even out the odds. A very good horse must carry more weight. The less weight the faster the horse runs. More weight also means more injuries. The horse's trainer weighs all of these factors when choosing what races to enter. The goal is to win every race. So showing off how fast a horse is at the beginning of the season will result in more weight being added early and reduce the chance of winning later. It will also increase the chance of injury. Even a strain will slow a horse."
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5o3qx0 | What is the role/ effect of music in human psyche? Why do some songs make us cry or some make us happy? | Why do music effects our brain the way it does? Why do few songs make me sad or wanna cry? How do I immediately get a feeling of transcending beyond limitations of time and space when I listen to few song? | Other | explainlikeimfive | {
"a_id": [
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"There is a ton of very cool practical and anecdotal information on this in this book: [Musicophilia] ( URL_0 ). This was the text we used in one of my graduate classes \"music and the brain,\" it's a very complex and not fully understood area. Almost miraculous in some instances. I highly recommend giving a look if the subject interests you.",
"I explained this to someone earlier using neuroscience: Music is of course sound, one of the most key elements of that sound is pitch, which creates melody and harmony. Pitch is really another word for frequency, or the number of vibrations a second. The language that our nerve cells (neurons) use to communicate is like frequency, it's the rate of tiny electrical bursts of energy sent into and out of the neuron. Nerves in your ear convert the changes in frequency in a song to changes in the speed of bursts, so music is all ready kind of \"speaking the same language\" as our neurons.",
"Music actually effects our brainwaves... ie some genres or songs like EDM or more upbeat music tends to have a positive influence on our behavior while aggravating music like rock or metal tends to make the waves and connections faster but more irritated if you get what I'm saying"
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5o3tlu | Why are there different versions of Windows? (ie Windows 10 Home, Pro etc) | Technology | explainlikeimfive | {
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"text": [
"Basically Microsoft could just sell the same product to everyone, but they want to make as much money as possible. They can't ask home users to pay the same high prices as business as many wouldn't want to pay that much and they can't just lower the price for windows for everyone to the same low price that every home user can pay. In order to maximize profits they want to sell the same product at different prices to different people They want to sell it cheaply to those who wouldn't buy it if it was more expensive and they want to sell it for a higher price to those who can afford it. So far so good. But how do you do that, you can't ask all customers to tell you how much they are able to spend before you tell them the price. If you offer it cheaply everyone will buy it at the cheapest price. To make sure that the customers with money (mostly businesses) buy windows at the more expensive price they split the product up into multiple versions (called editions or **SKU**s). They took the cheapest version and removed all sorts of features that you normally wouldn't need as a home user. Normal home users don't really need to domain join feature of windows so that gets excluded from the cheapest version. It is no loss for home users but businesses who need it will need to buy the more expensive version. Other functionality that you may not see in the cheaper editions of windows are stuff like drive encryption (Bitlocker) and similar stuff that are mostly needed or wanted by businesses. They also introduced all sorts of arbitrary limits that won't matter to normal users. Windows 10 Home edition for example only allows a maximum of 128 GB of memory, which is far more than any normal user would ever need. If you want more you need a more expensive version of windows. This was actually much more noticeable with windows 7 where \"Windows 7 Starter\" only allowed 2GB of RAM, \"Windows 7 Home Basic\" 8GB, \"Windows 7 Home Premium\" 16GB and \"Windows 7 Ultimate\", \"Pro\" and \"Enterprise\" allowed 192 GB of RAM. So they removed features and included artificial limits to ensure that people spend as much as possible for them on what is actually the same product. With Windows 10 at least Microsoft has limited the number of different editions quite a bit, there used to be far more in previous versions.",
"The simple answer is that it is making Microsoft more money and it is giving you more features. Although you do have to realize it is also costing Microsoft more money to give you those features. You have the obvious development costs, but a lot of features they have to either license a patent or the actual software from another company. The earliest instance I can think of this is HyperTerminal."
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5o3x4x | How does "double-jumping" on a trampoline work? | What energy transfer happens? | Physics | explainlikeimfive | {
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"text": [
"Double jumping occurs when you are jumping on the trampoline with another person and the jumps are timed in such a way that the stored energy of two people landing at the same time is converted to kinetic energy and applied to a single person. Basically, both people land, applying the weight of both bodies, but one person removes their weight first, basically doubling the rebound effect of the trampoline on the second person causing them to get bounced much higher.",
"The first person lands on the mat while the second person is in the air. The first person presses the mat down as far as they can when they land; first person is now stopped and waiting for their boost back upwards. A second person lands on the compressed mat at that exact moment, pressing it down even further. The mat falls out from under the first jumper, who is bracing for a boost back up which never arrives. The second jumper has stolen the energy in the mat from the first jumper, and gets twice the boost... a double-jump.",
"The farther you pull back a bowstring, the farther the arrow flies. Similarly, the farther you push down a tramp, the higher you'll bounce. When Billy double bounces Jeff, launching Jeff, Billy is pushing the tramp down right before Jeff lands. Thus when Jeff lands it is pushed down even farther than if Jeff landed by himself. The trick is that if Billy now stays standing on the tramp knees locked like Jeff, it will launch them both the same. But Billy quickly tucks his knees. While Billy is falling with knees tucked, the tramp is pushed down as far as the weight of two people can push it, but there is only one person standing on it, Jeff. It's a similar situation to if Jeff holds a cinder block on his head while jumping on the tramp and then at the very bottom of one bounce throws the cinder block away."
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5o3yf8 | why do we need to constantly change and adjust laws? | It's a very simple question with some obvious answers like "progress needs revising of some laws" "laws gets obsolete and need replacing". But even accounting for that, how come councils, congresses and parliaments need to work every day for hours to adjust it? It looks severely inefficient to me. | Other | explainlikeimfive | {
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"> It looks severely inefficient to me. That's because it is. I mean you seem to understand the need for some laws to be updated as the world around us changes. But yes, just as many are updated regularly because partisan politics means that different people have different opinions on the nitty gritty details of various laws and constantly fiddling with them is a good way for them to justify their jobs.",
"It's not just that laws need updating, but also that people disagree on what laws are desirable. So depending on who is in office, laws get introduced, then repealed, then re-introduced, then modified, then extended, then modified again, then re-repealed, and so on. There's no single recipe for \"how society should work\" that everyone agrees on, so every time a new person gains power, they want to change the current laws to better suit *their* vision for how society should work. You're right, if everyone agreed, then much of this would be totally unnecessary. But we don't. Some people want low taxes, some want extensive welfare systems. Some want to incentivize green energy, and others don't. Some think we should talk to the leaders of other countries, others believe we should fight wars against them."
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5o40v7 | How does part of a company split off into a sperate company? | Other | explainlikeimfive | {
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"text": [
"It is not a rebellion or mutiny. Companies have management. The upper levels are called senior management. These are generally people who have spent decades with the company and have a good grasp of how their company makes money. They often have degrees in business. Maybe they have advanced degrees. They understand things such as span of control. This is the concept that one person can only supervise a finite number of people. So they understand that a company can split into two groups who no longer consult each other and do not report to the same boss."
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5o47je | If the unreal engine is one of the most realistic and better looking game engines, why isn't it used more often in video games? | Other | explainlikeimfive | {
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"For indie dev: Game development is really, really hard already. If you don't need hyperrealistic graphics, why bother spending the extra hundreds of hours making detailed models, rigging them, creating animations, fine-tuning light sources, adjusting shader settings...? For established studios: Oftentimes, a studio will already have an engine they like to use, which they may have written themselves or bought from someplace else. Why bother learning a new engine and editor when you've already got experience with one that'll do the job fine? In general: It doesn't really make sense to say that the Unreal Engine, or any particular engine, is \"one of the most realistic and better looking\". That judgment is entirely subjective, not to mention massively in the developers' hands.",
"The cost is a big issue. The engine is free to start using, but you have to pay royalties if you make over a certain amount of money. So for big companies that expect to sell a lot of copies, the price may not be worth it. Admittedly big companies might be able to get a better deal, but they might still find other options make more sense financially. Being dependent on another company's technology also has some risks. What if Epic go out of business? Or they get bought out and stop selling their engine? Or they change the licensing deals? If those things happen you might find your company left without a tech base to make games with. So some companies prefer to invest in making their own engines so they don't have to worry about what might happen to that other company. Also that means their own staff have in depth knowledge of it instead of needing support from a different company. This also has the advantage that you can build the engine to your own specifications, you have complete freedom to optimise it for the games you want to make. Unreal isn't perfect either. Its very good, but maybe its just not a good fit for what you want to do. Maybe its easier to make your game in Unity or some other engine.",
"Graphics aren't everything in an engine. Keep this in mind, as it'll be important throughout the explanation. First off there's the licensing and cost of running an engine that isn't yours. In the contracts, some companies can charge a % of what you make past x amount. You can imagine the publishers, shareholders, and other such people won't be too keen on losing money the put in. The next bit is the physics requirements. Each game has different physics. Granted the projectile motion might WORK the same, but you might not get the same distances and etc. Another issue is how game mechanics can tie in with the engine. UE might not support levelution on the scale that Frostbite can in Battlefield. UE might have issues working Halo's balance of movement, vehicles, and gunplay. There's also necessity. The engine may have stuff you don't need, which has to be cut out or else it just adds to the end file size. Now we reach the grapics argument. In a sense, why do you WANT realistic graphics in every game? Look at Team Fortress 2 and Overwatch. Both have this cartoon feel to them. Borderlands focuses on their cell shaded approach to their style. Telltale games also do this too. Minecraft is self-explanatory as to why it's not necessary. Graphics and realism is nice, but the art style is where it's at. I can go and make a copy of real life, but where's the enjoyment to it? Where's the flair that separates it from all the other realistic copies? Now that real life copy I made won't sell as it's basically the same as everything else. Now if I accent something, distort the realism to something aesthetic, and capitalize on it, I can sell my copy. It's no longer copy of real life, but rather a copy of life that I see and enjoy. Another argument is developer preference. It's similar to cost, but this time focusing in on the actual makers, not the investors. You may have guys that are killers with one language, but less so with another. UE4 can force this to happen, instead of just making an engine with what you need. The last thing is what others are doing. If you just fall in with all the others, you can't set yourself apart. Setting yourself away from others and innovating with your own engine can boost marketing potential. [Here's]( URL_0 ) a list of all UE made games. You can see a lot of devs have been using it. You can also see that a lot of popular games don't use it at the same time. DICE has Frostbie, Crytek has Cryengine, 343 has...whatever they call theirs, Bungie has... also whatever they call theirs, Valve has Source, Alien: Isolation was made with a separate engine, Planetside 2 uses Forgelight, CoD games run on the IW Engine, Rainbow Six: Siege runs on the Anvil engine, and there are many other games running other engines. The reason we hear about UE and its use is that it's publicly marketed to indie developers. You won't get a copy of Forgelight, IW, or Frostbite all that easily like you can with UE or Unity. Now why did I say to remember that graphics aren't everything? Just look at this mini-essay. The best way to do this is to basically say \"Do I REALLY need a superpowered Formula1 engine in my Jeep? It's a great engine, but does it do what I need it to do effectively? Does it fit into my Jeep right? Can it help me with what I do with the Jeep, or is it just for the cool factor? Is this a smart, economically wise, thought out idea?\" TL;DR (Lazy copy/paste of quote above this, but this'll make it easier for y'all) \"Do I REALLY need a superpowered Formula1 engine in my Jeep? It's a great engine, but does it do what I need it to do effectively? Does it fit into my Jeep right? Can it help me with what I do with the Jeep, or is it just for the cool factor? Is this a smart, economically wise, thought out idea?\" EDIT: Thanks for my first ever gold! I totally will use it for... Idek wtf to use it for. I feel blessed, though.",
"Having a realistic, high fidelity game world isn't just about using the right engine. It's more about having really good artists make high quality art assets. And if you've got artists that are that good at what they do, they can make it work in any competent engine. Either way, it's very expensive. That's the main factor behind the high development costs of AAA games these days, paying an army of artists to make all of the art assets. And most of the bigger devs that can afford a team like that already have their own in-house engine that they're already familiar with and have an established workflow around. Unreal Engine does some pretty nice things graphically \"out of the box\", in that you don't have to do much extra work to get them in place. But it won't make crappy art look amazing, and it can come with performance costs and other issues that can be a headache depends by on the type of game you want to make. It is a high quality engine though. Certainly nothing fundamentally wrong with it, it just has some different priorities than other engines.",
"It actually is one of the most used engines: URL_0",
"It is used often in a lot of video games, so the question has a false assumption. **Why isn't it used in all games?** - It's expensive. - It requires a lot of different specialized skills to use. - It isn't suited for every type of game. - It's not ideal for every gaming platform. **Why is it used in so many games?** - It can be cheaper and quicker than making your own engine. - You can buy additional tools, like SpeedTree, to speed up development of your game. - You can get support for some of your technical issues. - There is a lot of documentation and other helpful resources available.",
"None of these answers really touch on the technical issues it doesn't end up getting used more often. Here are a few: Until very recently, it ran like crap on consoles and older pc hardware. In order to get it to be performant, you have to start switching off features like crazy. Eventually, it no longer resembles to beautiful tech demos that convinced you to use it in the first place. There's this thing called \"Garbage Collection\" that it does to try and free up memory that would cause your hardware to basically freeze and become unresponsive at frequent intervals. If you want it to run faster, you have to spend a lot of money making modifications to it. It also makes for gigantic assets. This isn't just a problem for hardware, but also for distribution. Patching levels might mean a several gig download. Take \"Ark: Survival Evolved\" for example. For the first few months it had an almost daily cadence of patching on Steam. Depending on your distribution platform and your business model, this can be cripplingly expensive, especially on consoles where the patch process can take a week or more to push through QA. The studios who adopted UE4 at day one found out the hard way that it just wasn't ready for shipping.",
"Soooo many games are made on it. I don't really get your point. Maybe its because I strictly play on PC? But seriously the amount of games that run on unreal...is well unreal.",
"There are probably many variables that affect what developers choose to use to make their games. It's not just about which engine looks best. There are also other factors such as ease of use and familiarity with the engine. For example, not everyone may have experience with Unreal, or would like to take the time to fully learn and master it, when they could use an alternative like Unity, which they may already have experience with. Secondly, when using third party engines, there's probably royalties that developers may need to pay. Thirdly, having your own engine means that you can tailor make something for your game and have better control, since an MMO and a racing game has different needs and optimisations. Developers also don't have to worry about the bloat that they do not need for their game. Finally, making something look good not only has to do with the engine, but probably the skill of the developer as well, although using an engine does make it easier.",
"I'm a game dev, and though I am not an engineer, I'd generally answer something like this... A game engine is a lot more than just a way to put graphics on the screen. It is a development environment for artists, level designers, animators, programmers, etc. It also manages all the data structures, netcode, etc. of the game and defines their most basic capabilities and functionality. Unreal is great at a lot of things (it has extremely good art and level design tools), but it has some quirks and weaknesses too that don't necessarily mean everything is a win (you wouldn't say, want to make an MMO with it). Even if we're talking about sheer graphical capabilities alone, Unreal is starting to get beat out on that front by other engines in the last few years. The new Tomb Raider, Metal Gear Solid, Doom, Dishonored, etc. all look just as good if not better than anything you could do in Unreal, and in large part because the engine developers are working directly in tandem with the game developers rather than doing everything \"off the shelf\". There's quite a few other good reasons Unreal has been feeling the squeeze in recent years, too. For one, the third party publisher-developer behemoths like EA, Activision, Square Enix, etc., the ones who used to keep Unreal afloat, have started pouring massive resources (hundreds of millions of dollars of development) into their own engine tech. About 5-7 years ago they began to realize it was better to do their own tech and have consistent communications, development and engine support structure across all their games and studios, than to depend on a separate company who would *maybe* get something they really need in for the next release in 6 months. Unreal is great, but if the engine doesn't do what you need it to, or has a critical bug, it can often cause massive stalls and headaches in development. Then, the competition available from other third parties has got way better too. Unity, especially, has become extremely popular in recent years. That is not a surprise. It might not have the sheer graphical grunt out of the box as other engines. However, it has a well-designed development environment, its generally rapid release rollout often means faster engine bug fixes, the asset store means you don't have to necessarily hire artists and programmers to make everything in your game (VFX is one place this is extremely useful), and of course, there is a massive developer community to turn to for support, and as it's being taught a lot in schools, there are *tons* of people familiar with Unity out there to help make your game. What else explains Unreal's decline and Unity's rise? A big part of it is simply that it's cheap, which helps a *lot* more than most gamers realize, as often game development is, for most studios, more about budget (time/money) limitations than it is technological ones. Unreal also gained a lot of traction because it was one of the first big engines to make its dev tools available to modders - many got their starts doing maps for Unreal and Unreal Tournament, which informed the tastes and needs of an entire generation of game companies. But, that modding culture has since dried up (or at least moved on), so there's less familiarity with and desire to use Unreal among developers. Last, Unity is also very versatile - everything from first-person games, to simulators, to racing games, to RPGs can run on Unity. It doesn't really excel at one particular genre, which on paper sounds bad, but in actuality means a dev team can hop from game to game much more easily. On the lower end, Game Maker is actually pretty capable, though I don't have a lot of experience with it. But, if you are an indie dev looking to make a 2D game, it's one of the more appealing options out there, and the games likewise will run on tons of target platforms with few if no modifications. There's just no reason for someone like this to even consider Unreal, yet games like Shovel Knight and Hyper Light Drifter have done *very* well lately. It turns out that 2D games are still awesome, and you don't need to have cutting-edge tech to be successful. There's two final things I would keep in mind that inform all this: 1) The goal of most game developers is primarily and above all else *to ship a product*. Anything not in service of that is very liable to get their business killed. Relentless pursuit of tech that is not in service of that goal is wasted time and money. And... 2) Game development is extremely hard, and takes a long time. You are working for years on projects which you *hope* on paper are going to be good, yet for about 85% or more of a game's life, it's actually a smoldering wreck. There are a *million* more variables in creating a game - questions like \"does the build even start?\" or \"did the Perforce server go down for the third time this week?\" or \"shit, we failed cert because someone forgot to test what happens if we leave the Xbox running for 12 hours straight on the main menu, and we have 6 weeks until our ship date, and Microsoft has no remaining cert slots for the next 4 weeks, we're so fucked\", are usually far more important concerns than \"does it do graphics good?\".",
"Serious question: why are you assuming that it's *not* used in an obscene amount of games? (Which it is)",
"Okay, so think of a game engine kind of like a plate for dinner. The plate, while solid in size and steady in build, can hold so much food (whereas food is data, code, assets, etc) Using an engine is sort of like hitting the buffet line with your plate, and your plate can hold all kinds of things, but some things go better on one plate than they do on others. Unreal also offers tons of customizable addons (condiments) that you can import to utilize. However, sometimes, it is better to grab a different plate for, say, dessert. You won't need as much surface area to store things (smaller scoped games) and it is easier to clean up and polish. Also, sometimes you will want access to a specific feature which, while supported by Unreal, would work better in a different engine; a standard dinner plate may be less effective for soup than, let's say, a bowl. An example would be the way Unreal Utilizes non-bipedal-legged movement (Unreal is not great for movement of creatures with more than 2 legs) so in this case, if your game was about animals, you might wanna go with a bowl instead. While you could certainly tweak code and modify the engine to your liking, it would be more timely and expensive to do so in some cases, so simply switching engines might make more sense. Another reason is because of complexity. Think of an engine like a car dashboard. A really high-end, luxury car might have 30 dials and buttons to play with. This is well and good if you want to customize, say, your sound system in that much detail (how much treble is coming out of speaker 3 in the back left corner of the car) But maybe, you are just looking to turn the radio up, and you don't care what is playing. All you really need is a power button and a volume dial; the rest doesn't matter to you. The same happens with game engines; a lot of people who are learning or practicing within an engine aren't interested in all the features available, so they opt for a smaller, simpler engine that is easier to configure. A final, simpler example would be like buying a vaccum cleaner. Sure, you could buy the Dust Buster 1000 Mk. 7 Ultra Deluxe Collector's Edition vacuum cleaner for your house for like $2000... or you could go get an Oreck for $29.99 at Sears. Both will clean your house, one will be packed with way more features and fluff, but both are capable of doing the job; it is a matter of what you need for the task at hand. Tl;dr: Size, scope, functions, team size, timelines, budget, and project goals dictate which engine makes the most sense, not just the raw power of the engine.",
"How is this not just a biased gaming opinion posing as a question? This is poor ELI5 material.",
"There are many ways to approach your question. The pedantic answer is that engines can't really \"look realistic\", since a game engine doesn't look like anything. They offer features and tools for artists and programmers to realize their vision, but they don't look like anything without the assets the artists create for the game. While games created with the same engine can share some similarities (due to built in assets and effects), most engines are flexible enough to support any kind of art style, realistic or non-realistic. For instance, Dota 2 and Titanfall 2 run on the same engine (Source Engine ^(though heavily modified in both cases)), as do Hearthstone and Cities: Skylines (Unity Engine). While a good game engine helps with creating believable and realistic-looking environments, it's not the most important factor. The assets (models, textures, animations) are arguably far more important. Creating high quality assets is very time consuming and therefore very expensive. Even though a single developer or a very small team can create a game using Unreal Engine 4 or CryEngine, the game will not look nearly as good (meaning realistic in this context) as one created by an AAA-developer, since they lack the manpower required to create enough high quality assets. The game engine is not the bottleneck, the budget is. As far as I know for big budget AAA-games Unreal Engine is *the* most used game engine of all time, and has been extremely popular for the past 15 years. There's [an incomplete list of games built with UE in Wikipedia]( URL_0 ), and it's absolutely massive. However, the most popular version of the engine is the 3rd version, which is still used for some recently released and upcoming games. While the 3rd version was very advanced at the time, it's over a decade old at this point. The engine's 4th major version was released in 2014, offering a huge leap in graphical fidelity due to several new advanced features. Quite a lot of games have been released on it already, and more are coming in the near future. Games can take a lot of time to develop; a game started in 2014 might take 4 or 5 years to finish it. Even though it's pretty popular, why isn't it even more popular? Many AAA publishers have their own internal game engines, which they use for multiple different franchises. For instance, EA uses DICE's Frostbite engine [for most of their high-profile titles]( URL_1 ). Additionally, some games wouldn't necessarily work that well on UE4 in terms of technology and design, at least without changing their scope or making large modifications to the engine. For indie developers, Unity has a larger market share. While UE4 has no upfront licensing costs at the moment, it used to cost hundreds of thousands of dollars just a few years ago. Unity on the other hand has been available for free since 2009. It offers less control for developers compared to UE4, but it's arguably easier to use and has a larger community. Unity also has lower system requirements, which makes it a better platform for mobile games. It's arguably less powerful in terms of sheer performance and graphical features out of the box, but since indies lack the budget to create photorealistic assets anyway, it's not a huge issue. For indies, speed of development, the community and portability are far more important than the maximum attainable graphical quality.",
"I'll just add to all good answers here the POV of some gamers: Not everything has to be realistic and detailed to be great game. Back in the days we had Crash Bandicoot and other games where characters were nothing more than polygons with mouths moving up and down without any gesture on what the character was saying, and we were happy with it. Grat games were developed that way. So if adding realism in the game doesn't sum to the overall experience for the player, is not really worth it to code it that way. Just my two cents.",
"Because gameplay is more important than shinies, taking advantage of 100% of the graphical capability is very expensive, and building your own engine allows you to customkze and tweak it to your neess.",
"My son and I are looking to do some inde game development. We looked into Unreal and Unity. We decided to go with Unity for 3 main reasons. 1. Unity has a lot more assets in their store than Unreal. 2. There seems to be a lot more online courses you can take to learn Unity. 3. Ai, for some if our ideas we need really good Ai and again the asset store from Unity has a lot more choices that will save us tons of time vs making our own. Other than that we also felt like unity had a much smaller learning curve than Unreal. As to you question about better looking graphics I think that just has to do with how much time and money you have and there are a few places online that sell really high quality 3d assets and models that you can import into unity. Check out URL_0 for example.",
"Unreal engine isn't a \"better looking\" engine. It doesn't magically make amazing graphics. Its a framework. If you have a certain kind of game you want to make it can have far better performance and graphics if you create your own engine designed specially for your game. That's what i'm doing.",
"Big game developers generally have more streamlined, more focused game engines that carter to what they want to bring with their games. It's also easier for them to use because most of the time it's in-house software that they've made themselves. Perfect example would probably be Frostbite for DICE. Smaller devs can't really use it for making money since they'd have to pay a pretty hefty royalty fee to make use of it and then it's a waste of money because you're paying for its full capabilities which more than likely you won't need or won't be able to make use of.",
"This has a really easy explanation: graphics vs features. Every hour you spend working on graphics is one hour you won't dedicate to creating features and solving bugs. On a indie dev's case, they have limited manpower, and often choose to make less \"pretty\" graphics to give the game some substance. On a big studio's case, they often work with a time limit, so even when they have the manpower to create both pretty graphics and give the game substance, they work towards a release date so they can create hype soon before release to get more sales. And now let's talk about you: What would you have, pretty graphics or enough content to enjoy the game for more than one hour?",
"People who say that it's not used by indies because it's too difficult aren't really correct. Just because you can can make highly detailed assets doesn't mean you have to. Blueprints, a visual scripting system, also make programming fairly easy and accessible for everyone. In my opinion, at least when it comes to indies, it mostly boils down to marketing and/or already having a good bit of experience with engines which came before UE4, such as gamemaker or unity. For triple A, I think, the answer is purely economical. If creating an in-house engine is cheaper than what you'd expect to pay to epic in licensing fees, you write your own. If modernizing your already existing engine is cheaper than the licensing fees, you upgrade."
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5o4p4l | How come you can restart the heart to start pumping again, but you can't do the same to the brain once activity ceases? | Biology | explainlikeimfive | {
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"Nervous tissue has a drastically different recovery process (and is much less apt to regenerate unused pathways etc.) than muscle tissue like the heart. So when the heart stops beating briefly, an electrical or mechanical stimulus can get it back to its normal rhythm, but when the brain's neural pathways go unused or incapable, this repair is not as simple as electrical stimulation."
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5o4x9q | Why do drummers generally cross their arms when playing? | Other | explainlikeimfive | {
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"The hi-hat is generally positioned on the left of the snare because its pedal needs to be accessible by foot. The bass drum is traditionally played with your right foot so then the hi hat is controlled with the left. The majority of people are right handed so they play crossed so that the dominant hand is striking the hi hat. Of course plenty of drummers are left handed or just prefer to play open handed - it all depends.",
"At this point it is mostly historical. It was almost always done that way due to needing the left foot to control the hi hat and most players being right handed. Now we have remote hats and you can place them wherever you like but we still see most players playing crossed because it is how they learned and how they are comfortable. You will also see some players who continue to play with traditional grip, it is a holdover from military days of drums mounted on slings which required the left hand to hold the stick in a traditional grip and while it serves no such purpose on a drum set, many people learned that way and feel more comfortable using it.",
"Actual drummer here, it has to do with your foot controlling the hi hat. Now you can place the hi hat on the right side and play un crossed but you would need a hi hat that it set up remotely. Back in the day they didnt have remote hi hat stands, all they had was the normal hi hat stand, so you would have to play crossed hand. You can play open handed but this is more for left handed dominant players as your left hand is leading rather than your right, but most left handed dominant players set up their kits mirrored and still play crossed handed. It has nothing to do with \"looking cool\" or \"showing off\". Its simply because your left foot has to control the hi hat."
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5o4xjo | Why does mold grow on "dead" fruits but not on the ones still on the tree? | Biology | explainlikeimfive | {
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"Mold doesn't grow on living things because living things have immune systems. Fruits on a tree are being kept acidic by the physiology of the living tree. Mold spores that land on them can't survive. When the tree severs it's connection to the fruit it will start to change chemically, even if we can't see it. Without the tree maintaining a chemical resistance the fruit become a habitable environment for mold.",
"Unless I'm mistaken, mold actually DOES grow on some fruits \"on the tree\", most notably grapes. The most known being Botrytis.",
"It does grow on the ones still on the plant. You just don't see it as much, because you have a lot more experience with picked fruits than you do with those still on the plants. Go strawberry picking towards the end of the season sometime ;)"
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5o56nm | How do game developers secure their code for their game in that way that it simply won't be copied by any other game company/game developer? | Other | explainlikeimfive | {
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"Most games are written in C++. When you program something in C++ you run the code through a program called a compiler, which turns it into a form that the computer can run. You can't get back to the code that was originally written from that, too much information is thrown away. It is possible to inspect this compiled to code to reverse engineer or hack parts of the software. But reverse engineering it into something usable to make a new game is way more difficult than it would be writing the code for your game from scratch."
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5o5emg | Why do we sometimes have to rotate a cord to put it in the outlet because it won't go in the other way | Other | explainlikeimfive | {
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"If you're in the US, it's because those plugs are polarized, where one prong is wider than the other, for reasons I'll leave to engineers and electricians. If you're not, or if you're referring to USB plugs, it's a similar situation except it deals with pin placement and contact between the plug on the device and the port in the computer. Until the update to USB-C plugs/ports and USB 3.1 architecture the plug could only go in one way, but a USB-C plug/port has no “upside down” as such, as well as having a single port design for input and output. By this I mean that it doesn't matter which end of the cord you plug into whichever devices you want to connect, unlike previous iterations of the USB standard that used different shapes and configurations for the B-side plugs that pop into devices like smartphones and digital cameras, with the larger A-side plug that connected to the computer. For example, I'm typing this on my phone, a Nexus 5X from Google. It has a USB-C port for charging on both the wall plug and the phone itself. I can switch the cord around to charge with the other end and have no problem, though I'd need an adapter or a cord that has and A-side for the computer and a C-side for the phone. My previous phone was a Nexus 4, which has a micro-A port for charging and data transfer. Sorry this is long, but I wanted to be thorough, and I'm a bit of a tech nerd. Good day!"
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5o5ftc | How did English become such a prominent language? | Whereas other languages never really caught on. | Other | explainlikeimfive | {
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"1) England had several waves of colonization--from settling North America (1600s and 1700s) to settling Australia and New Zealand (1700s and on) to conquering India (1700s and 1800s; that today pretty much every educated Indian speaks English, and given that many Indian languages are mutually incomprehensible, that makes it the unofficial national language) to conquering much of Africa (late 1800s; so ditto for many Africans). At the peak, the [British Empire ruled 1 in 4 people on earth]( URL_0 ), by far the biggest empire in history. 2) England didn't just go around conquering people--they were a massive commercial power (the first nation to industrialize). In the early 19th century, if you wanted people who knew how to build a railroad or a telegraph or a factory, you needed to deal with Englishmen. In the late 19th century industry had spread, but if you wanted access to the top financial markets, you needed to deal with Englishmen. 3) This wealth and technology meant lots of research; if you wanted to keep up on the latest science or technology in your field, you needed to keep up on English-language journals. 4) In the 20th century, England's position slipped. But England's global dominance was inherited by the USA, so English remained the language of international commerce, diplomacy, and scholarship. 5) The USA was also a cultural powerhouse; English-language books, movies, and TV help spread the language.",
"Colonialism. England settled vast territory from India to the Americas to Africa, and their language went with them.",
"One of the largest and most prominent commercial empires of all time with world-spanning influence happened to speak English, and everyone learned English to trade with them or trade through their routes. Their empire basically fell apart over the first half of the 20th century, but their successor (as a rebellious colony of that commercial empire) happened to also speak English."
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5o5fxb | What did all the billions donated to cancer research over the years achieve? | Biology | explainlikeimfive | {
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"Dramatically increased survival rates for many types of cancer. Cancer isn't one single disease. There are many different kinds, and they behave differently and have to be studied and treated differently, which is why we haven't \"cured cancer\". Many kinds of cancer are curable today, and as long as they're discovered in time, people actually have a good chance of surviving. But there are still many other kinds that we still struggle to deal with, especially rarer forms that haven't been studied as much. But in short, all the resources we've pumped into cancer research have actually paid off. We just haven't cured *all cancer ever*.",
"Even though it may seem not much has been achieved, the work for understanding cancer has done forward. Cancer is not one disease like flu or heartattack is. It is more like umbrella term for all diseases where your body starts to multiply cells incorrectly creating mutants that are harming you. It is like you can say fruit or sweet pea. You know what fruit is but there are multiple different fruits (apple, orange, grape, melon...) For example surval rate of breast cancer is 99% if it is only located in the breast, 85% if it has formed lymph nodes elsewhere. In the 70s same survival rate was less than 40%.",
"Im gonna go out on a limb here and say finding new ways to treat and cure cancer?",
"It goes to finding and testing new treatments, for one. There are so many types of cancer, and research goes to developing and testing more types of treatments. At my last Relay, a survivor told us his story, and how the most recent treatment he started was only developed the previous year. If you know anyone whose cancer has metastasized, and are still alive, they're likely on one of a few of those new experimental treatment plans. But it's not just for research - money can also go to basics, like helping patients get TO their treatments, help pay for hospital stays, and further testing. Every dollar counts!"
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5o5k6i | What was the Mexican Revolution about? | Other | explainlikeimfive | {
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"Long story super short, the dictatorship of the president at that time was already on command for 35+ years, and with social injustices to lower classes, and taxes for things like having an extra window, the people decided to arm up. The president at the time \"Porfirio Díaz\", was in close relation to the European kingdoms, to wich I understand wanted us to be a kind of colony/ally, so they injected lots of money to the country in that era (train tracks all over the country, etc), hence the progress and advance in México of that years. Source: Am Mexican Edit: Typing"
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5o5lbz | Why does online banking (transfers, deposits, etc) cease to operate on the weekends? I would think that me transferring money would be entirely automated and does not require any human involvement at all. And even if it does, why not have some people working on the weekend to help out? | Economics | explainlikeimfive | {
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"It doesn't for companies and corporations and the super rich. Just the general public. There's an important legal and regulatory reason for weekends and holidays which that is that it makes it possible for regulators to deal with a major crisis. In 2008, there were several points at which central banks provided enough emergency cash to keep the system going until the weekend, at which point the world banking system went off-line, and you could have a meeting to figure out what to do next. For the first few weeks, it was an hour-by-hour struggle to get to the weekend, at which point the system went off-line, and there were big meetings to figure out what happened next. This also works for bank failures. When FDIC wants to close a bank, they typically do it close of business Friday. The bank is quickly wrapped up and resold during the weekend, and the bank opens up Monday morning, and no one notices a difference except for a white sheet of paper tape to the door. If you don't have the system go off-line, then it becomes much more difficult for FDIC is close a failing bank. Something about banks is that once they post hours of service they legally *must* fund withdraws during those hours. If the bank funds a $1 transaction on Saturday, they can't legally step a $15 million withdrawal, and during the financial crisis, weekends became very important for at least putting some speed bumps in the withdrawals. For this to change, you will need banking regulators to step in (because it makes no sense for one bank to transfer money on weekends, if no other bank will accept it), and given how vital weekends were for them, I don't think the regulators will change the rules.",
"I just sent and E-transfer and they accepted it in less than 15 minutes and it's 1PM on a Sunday. Switch banks??"
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5o5n0q | Why are USA and Russia still antagonistic against each other in 2017? | I fully understand the cold war and why tensions were high back then, but what barrier prevents these two giants from sitting down today in 2017 and getting along? | Other | explainlikeimfive | {
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"On the one level, you still have a lot of lingering stuff from the cold war. Both countries have had decades of propaganda demonizing the other, and that stuff doesn't just go away. Just think of how many movies you can remember with Soviet/Russian bad guys. Plus, many other countries were pushed to choose to ally with either the US or USSR during the cold war, and those relationships tend to endure. For example, the US is closely allied with Israel and Saudi Arabia, and Russia is allied with Syria and Iran. So if those allies start fighting, we each back our boy, and suddenly we're facing off again. When we have a beef with Iran's nuclear program, when we fund anti-Assad rebels in Syria, we're indirectly screwing with Russia. You also have the fact that even after the breakup of the Soviet Union, the US and Russia still have giant nuclear arsenals pointed at each other, and still make many of the same provocative moves- flying bombers close to each others' airspace, etc. Setting that aside, there's also lots of modern stuff. The US has taken umbrage at a lot of human rights issues since Putin has come to power. Lots of silencing of dissent, revisionism to keep power in the hands of Putin, etc. You also have a lot of kleptocracy and corruption by the oligarchs that wound up in control of the de-nationalized industries after the fall of the USSR. All of this is stuff that the US can be talked into looking the other way for an ally (like Saudi Arabia), but for a rival it turns into a bit of a sore point. On the other hand, Russia's been in a pretty tough position and we haven't been helping. Many post-soviet eastern European countries have been moving closer to the US or EU, with some even applying for and gaining NATO status. Russia (arguably rightfully) sees this as highly provocative and a slow-motion invasion to put enemy troops on their doorstep. This is also coupled by stuff like plans to introduce new missile defense systems. They seem harmless enough when you first hear about them- no one wants to get nuked- but they potentially break down MAD by making it so that we could bomb Russia but they couldn't shoot back. In recent history, the big issue was Ukraine. After the corrupt Pro-Russian ruler was thrown out, mysterious troops without insignia who spoke Russian and used Russian military equipment appeared in Crimea and took it over. The US and EU had a lot of reasons to find beef with this. It was a pretty clear trampling of Ukraine's sovereignty just as it had been leaning towards the west, it was blatant expansionism on Russia's part, and those sorts of plausibly deniable military tactics are actually super dangerous. They're a way of waging war while trying to escape responsibility for it. There are spots in the Baltic states very similar to Crimea where the same excuses Russia used would apply, and some of those are NATO states with NATO troops on standby. It's a troubling situation. If Russia repeats this there, do we Article 5 up and go into an undeclared war with Russia? If we do wind up there, what happens when one side starts to lose? It's a short jump from undeclared war to declared conventional war to nuclear war. Anyway, as a result of the Ukraine situation the US and EU made a bunch of sanctions against Russia, and Russia does not need this shit right now. They were already in a tough spot economically. The US and Canada started making a bunch of oil and gas through fracking and tar sands, etc. The Saudis cranked up production to try to crush those more expensive techniques, and sent the price of oil plunging, which hurt Russia, which depends on fossil fuel sales. The whole Crimean invasion was half a political cover by Putin to try and distract the Russian people from economic news. And now they have sanctions on top of that that nuked a bunch of deals like the $500 billion Exxonmobil arctic drilling deal that was negotiated by Tillerson, Trump's pick for Secretary of State. So the Russians wound up monumentally pissed about these sanctions, which is how you wound up with them hating Hillary and supporting Trump, who was either mysteriously pro-Russia from the start or was incredibly pliant to changing to a pro-Russian position in return for their releasing hacked intel on the DNC. TLDR in addition to old cold war legacies, we don't like Russian human rights abuses, they don't like us moving NATO up to their border, we don't like them invading Crimea, they don't like us putting sanctions on them. And now we're super pissed about them meddling in our elections and helping a massively unpopular prick get into the white house.",
"Each country thinks the other is threatening their way of life. I don't want to make a value statement because there are very legitimate concerns that each country has against the other one. But I think it boils down to that. It's also worth mentioning that the USSR dissolved in 1991. So \"the cold war\" \"back then\" is within the lifetime of a 25 year old person. It's still VERY recent. The bulk of the cold war that we talk about was pre-Vietnam, but Bush 41 started as a Cold War president.",
"Their position as one of the active global players that can interfere with each other's agenda. Europe is increasingly splintered. China is currently only openly interested in its local area.",
"> but what barrier prevents these two giants from sitting down today in 2017 and getting along? More or less the same ones in the cold war. You say sit down and \"get along\", but they tend to have very different goals and agendas in global events. Russia has increasingly been trying to reestablish itself as a global power What is good for Russia is not necessarily what is good for the U.S. For example, Syria. Russia considers Assad an ally, and has pushed to keep him in power. The U.S. sees him as a dictator who's killed a bunch of his own people, and has no particular reason to want to keep him in power. The only way to compromise is to just accept a loss in Syria. Why would you do that? Each country wants to maximise it's own power and/or vision for how the world should be run. That's going to clash. There *are* a lot of things we cooperate on, that we didn't use to. But you don't tend to hear about them.",
"The USA and Russia still don't have similar interests that would encourage the cooperation you envision. The two nations don't have much of a problem sitting down. They never have even at the height of the cold war. But the ability to sit down does not translate to the aligning of interests and values.",
"Russia is essentially a kleptocracy right now. The only way for Putin to keep himself in power is to keep giving people loyal to him new stuff. However, their economy is mostly broken, except for the oil and gas industry, which is hurting due to global oversupply at the moment. Thus, Putin grabs Crimea, and tries to keep the industrial east of Ukraine in his orbit. Putin is not an existential threat like the USSR was, but the corruption that spreads from Russia is a chronic disease that Europe and the US must deal with."
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5o5owh | Why do we have bad dreams? more specifically; bad recurring dreams? | Biology | explainlikeimfive | {
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"Im by no means an expert but I learned about this in psychology. There is an idea that your amygdala is the part of the brain that controls fear and anxiety, not scientifically proven though but there is some evidence to support this. Anyway, if you look at cat scans of people sleeping this part of the brain is very active during R.E.M sleep. One theory that made the most sense to me was that our dreams are filled with anxiety and fear because they are meant to prepare us for real life situations where we are put under stress, and that dreams are a strengthening mechanism. Now how much of this is true is still a debate, there is still a lot we do not know about the brain."
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5o5sna | The difference between the Common Law system and the Civil Law system. | I was just reading this [post] ( URL_0 ) and I'm having a hard time understanding the difference between the two prosecution systems. | Other | explainlikeimfive | {
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"Civil law is a law system where almost all things are written down. That is to say, judges follow the law code that has been enacted by parliament and the government. Judges rulings apply only to the case at hand; while they might persuade other judges to come to similar conclusions, they are not binding. That is to say, if the supreme court of a civil law country says that a law should be applied in a certain way, lower-level judges (such as local judges) can enact the law differently. Common law is a law system where judges' rulings have more power and are binding for lower-level (and sometimes same level) judges. That is to say, when the supreme court of such a country comes to a ruling, other judges in the country have to apply the law in the same fashion. Another big difference is how trials are run. In civil law countries, judges are \"investigators\", aided by the prosecutors and defendants. Judges are allowed to ask questions, and sometimes ask more questions than the prosecutors. They are acting as a \"neutral party\" whose goal is to establish the facts and make a fact-based neutral ruling. Prosecutors in criminal cases are at least in theory asked to help the judge, and sometimes do not much more than press charges and present evidence, with the judge interviewing witnesses. In common law, judges typically act as \"arbitors\". When a jury is asked to find the facts, the judge is making rulings as to how interpret the law, but not on facts. The prosecution and the defense try to establish a story by interviewing witnesses, and the finders of fact (either a jury or a judge) rules on which story is more convincing. The main difference is really who asks questions, and whether court rulings are binding for other courts."
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5o61jb | Why does color affect heat absorption? | Physics | explainlikeimfive | {
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"It's not color that affect heat absorption. It's the physical propriety of material that absorb different wavelenght of light. So if a material absord all visible wavelength of light it will appear black because it doesn't reflect back light into our eyes. Alternatively, something white is made of something that reflect all the visible light back so we see the color white. Something that absorb more wavelength will absorb more energy from that light, which will become heat.",
"Color is a *symptom* of light absorption. Items appear light if they are reflecting light away. Items appear dark if they are absorbing light -- which will of course mean they are going to warm up."
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5o64mq | Why does ice pressed on salt produce temperatures of - 28°C? | It's called the "salt and ice challenge" and it's destroying children's hands in the UK at the moment | Chemistry | explainlikeimfive | {
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"Salt lowers the freezing point of water, ice is already frozen and so the salt melts it and when a material melts the bonds between the molecules break apart. Breaking bonds requires energy and heat is the energy used to break these bonds which lowers the temperature of what ever the heat is coming from, in this case it's some dudes skin effectively freezing it.",
"There are three important parts needed to understand why that happens. * When two bodies (ice and your arm, for example) is in contact, the temperature will equalize. Heat will flow from the warm object, into the cold object. The bigger the difference, the faster the transfer. * Salt lowers the freezing point of water. Normally, water is said to have a freezing point of 0°C, but that differs by salt content. With 20% salt, it would be around -20°C instead. * Changing state requires energy. This is the tricky one. Going from ice to water takes energy. This means that melting ice will get colder than it originally was, and thus draw more heat from your arm. Reversely, going from water to ice releases energy, so, when freezing water, you actually end up with ice just above the freezing point - for a moment. So, all three points combined: When putting salt and ice on your arm, ice actually gets colder, in an attempt to melt. You being the only source of heat, therefore has to provide the additional heat. And finally - FROSTBITE IS A REAL THING! If you do stupid stuff, stop doing stupid stuff and seek medical attention!",
"Ice is normally stored at -18°C in a freezer. When ice melts the temperature rises to 0°C. When salt is applied the melting point drops so the liquid melt can then be at a temperature of say -5°C, add more salt and the temperature drops more. At around -10°C frostbite is a risk."
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5o68yf | Why does animal tissue smell pleasant while cooking but human flesh smells so badly when burnt? | I have family and friends that work in health care and have seen many burn victims. They say the smell of burnt human tissue is one of the worst smells they have ever encountered. Yet you can roast an entire pig over a fire pit and it doesn't stink. | Biology | explainlikeimfive | {
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"It's often not the flesh that smells horrible in humans, it's the hair and other stuff. I would suspect (obviously I don't know) if you prepared CUTS of human (like we do when we cook meat) it would actually smell good, or at least like other meat. Burnt hair is a HORRIBLE smell though."
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5o6cww | How do Speedometers work? | I have a rather large truck with large wheels. I have always assumed I travel faster than other vehicles because of how big my wheels are. The other day my girlfriend was driving behind me and I was only going 55 mph while she told me she was going at least 70 mph to try and keep up with me. How is it that I never get a speeding ticket although I am going faster than most vehicles on the road? | Technology | explainlikeimfive | {
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"Speedometers measure the speed of a vehicle by using a magnet attached to the vehicle's transmission through a series of gears. As this magnet spins it interacts with the speedometer needle and pulls it a certain amount depending on the speed of rotation of the transmission. speedometers must be calibrated so that the amount the needle is pulled accurately reflects the speed of the vehicle and the difference in speed you describe is most likely due to either your's or your girlfriend's speedometer being calibrated incorrectly. Tire diameter can affect the speed of your vehicle without changing the measure speed on the speedometer, so if you have much larger tires and in particular if these were not the original size of tires of the vehicle this could cause the reading on the speedometer to be incorrect For completeness: Electronic speedometers work in a similar way, just the reading is transmitted to the speedometer by wiring from the transmission instead of mechanical gears"
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5o6gop | why do we get itchy? | Biology | explainlikeimfive | {
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"An itch is usually caused by something brushing up against the hairs on our bodies alerting our brains that some thing is on our body, and the tickle sensation from it makes us react like swatting a bug as a defense to get whatever it is off as soon as possible. This is similar to why we laugh when tickled, many of us are ticklish in sensitive and important areas of our bodies, e.g. armpits(soft tissue, major blood flow, no bones), lower ribs, belly(no bones, major organs), inner thigh(major arteries), which are all crucial. When those parts are touched, our laughing is supposed to be a defensive mechanism to startle whatever is touching us with a sudden burst of loud noise. Of course, we don't live in the jungle and don't have to worry about a dangerous animal crawling on us in our sleep or anything, but that's what it's for."
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5o6j03 | Why does microwaving a lit candle create plasma? (Do not try at home) | Physics | explainlikeimfive | {
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"Not a scientist, physics major, or anyone who's explanation should be taken seriously, but I did a little reading on it. Sounds like plasma is just free moving charged particles, either negatively or positively. You can make plasma by heating a gas. So basically the microwaves start knocking the crap out of all the particles (the gas/flame created by the candle) that are already pretty goddamn hot. This either adds or removes lots of electrons from the particles, thereby making them either - /+ charged. I would wonder what would happen if you had two highly, opposite charged terminals on either side of the microwave, but out of the way of the microwaves themselves. Could you create arcs through the plasma? Isn't that kind of how lightning works?"
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5o6l23 | How does health insurance work at all if everyone needs it? | For most other types of insurance, everyone pays into a big pot because most people probably won't need to take it out, but one person may. For example, everyone pays into fire coverage, and there will probably only be a handful of those people that need it, but when they do they will be covered because everyone paid a little bit towards it. But, my question is, how does that work for health insurance at all if _everyone_ needs doctors' visits and whatnot? Why do we use this insurance model for something that everyone needs rather than trying to come up with a different model? How does it keep funds from depleting faster than they are being added? I'm in the USA if that matters. Thanks! | Economics | explainlikeimfive | {
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"> But, my question is, how does that work for health insurance at all if everyone needs doctors' visits and whatnot? Most people need regular checkups, but not everyone needs to get brain surgery, chemotherapy, or organ transplants. It's the latter items that are extremely costly to both the insurer and the patient. Regular checkups can prevent severe health issues from occurring before it's too late, so routine checkups are covered as an incentive for people to get them.",
"One of the key parts of ACA was all people were required to have coverage. This is because younger, healthier people think they don't need coverage. But they also pay more into the system per year than they use while older, less healthy consume more than they pay in. If people all wait until they are old or sick to buy coverage, then there wouldn't be the years of paying in to cover the years of over-consuming. And then everybody would end up with paying super high premiums. But if you pay $5000 a year now and use $500 for a physical and a couple basic visits that additional $4500 pays for the cancer patient. And some day, you'll be the cancer patient or stroke patient, and somebody else will be the healthy person paying more than they use.",
"You just struck on what's at the heart of America's current healthcare woes. Previous to the ACA, insurance companies wouldn't cover people with preexisting conditions unless they were willing to cover the risk by paying absurd premiums. Insurance companies would also apply lifetime caps. If your cancer treatment was keeping you alive longer than you expected and going over budget, you'd be cut off and left to die. The ACA has essentially morphed the brutal insurance model into a half-assed universal model by requiring everyone to buy in or pay a tax penalty, and by removing caps and preexisting condition requisites. Despite the fact that almost everybody who doesn't die suddenly and unexpectedly will eventually need expensive treatment for a chronic condition, the insurance companies have managed to eek out a profit, mostly on the backs of small businesses and the middle class. We're also seeing the co-ops die out while major insurers merge and stifle competition. They are providing as little and charging as much as is allowed by the law, they are driving healthcare costs up by playing middleman, and our healthcare is overly complicated and tied up in our taxes and employment. Meanwhile, there are a great many people who cannot afford healthcare despite having \"decent\" health coverage. Any meaningful repairs to this system will have to come in the form of some sort of actual universal healthcare. However, insurers, big pharma, and the ultra-rich who stand to lose a few points on their taxes are fighting this tooth and nail. They also happen to have more influence on lawmakers than the average Joe, not to mention the average lobby. Working together, the people of this country can influence this necessary change, but with our current government and state of divisiveness, I don't find it likely. Indeed, it may be a full repeal and the resulting chaos that gets a big enough majority on board.",
"Not everyone needs it at the same time, and insurance companies make more from their investments than they do on the premiums.",
"You didn't have to mention you're in the USA, no other major country does this and they all pay a lot less for healthcare overall.",
"> But, my question is, how does that work for health insurance at all if everyone needs doctors' visits and whatnot? Everyone needs to go to the doctor every once in a while. But not everyone needs state of the art cancer treatments. Not everyone needs drugs every day for the rest of their lives to combat autoimmune diseases, or painkillers because of chronic pain. Not everyone breaks their leg, not everyone gets pregnant. The amount of health care we need varies wildly."
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5o6lhu | How do we create "easy" AI in video games? | I understand how artificial intelligence works in general, but my question is how do developers make "easier" AI in video games? AIs that make mistakes and can be easily outsmarted or outperformed by a human? | Technology | explainlikeimfive | {
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"Depends on the game really. In games like chess you can adjust the difficulty by telling the computer to not look so far ahead. In games like FPS's it's actually hard to make a good playing AI, movement and tactic-wise. They try to make the AI as good as possible here. Aiming-wise, on the other hand, AI could be made unbeatable of course, so they can for example penalize the AI's aim by randomly \"poking\" it in a certain direction, making it wait for a while before shooting to simulate human reaction time, etc. In games like Warcraft III, they actually had to make the hard AI cheat by mining more gold than the player, and still if you were good, you could beat it easily. So I really think that the problem with AI being too good is only when it comes to precision, in which case they simply penalize it with randomness.",
"Most Game AI just detects certain events that occur and then chooses a set response from a list of responses. For example, a monster can trigger some logic when their HP drops below 20% to randomly either 1) Become enraged and charge at the player or 2) Run away and cast a self healing ability. If this was an easy difficulty maybe this can be tweaked so that the monster runs away more often or maybe the healing is not as effective. Maybe the monster has less HP overall or has a lower attack rate. This isn't what computer scientists would consider to be real AI. Real AI in games such as chess would look several moves ahead and anticipate the opponent's response to each of the possible moves and will choose the move that will put it in the best position. In this case lowering the difficulty will limit how many moves ahead the AI can look."
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5o6sk5 | What is the difference between "vis-a-vis" and "via"? In what situation would you use one over the other? | Other | explainlikeimfive | {
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"They're just completely different words. Vis-a-vis means \"in regard to\" and via means \"by way of\"."
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5o6u6x | I often see people refer to the US presidency with titles like "the world's most powerful office." Is this just America jacking itself off or is there actually stock in a statement like this? | Other | explainlikeimfive | {
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"The US is politically, economically, culturally, and militarily dominant in the world. The President of the US has wide ranging powers when it comes to how the US interacts with the international community. So I would say that describing the presidency as \"the world's most powerful office\" is accurate.",
"The US President is the commander in cheif of the US army, which is by every objective measure the largest, most powerful, most advanced military force in the world. The US president also has a degree of executive control over the US economy, which is, by every objective measure the largest, most powerful economy in the world. Most power over largest collection of weapons and money in the world. It's actually beyond question that the US president is the most powerful office in the world, regardless of one's stance on whether or not that office is well run or like-able.",
"The United States is economically, politically, and militarily the most powerful nation in the world from 1990-Present. From 1949-1990 they were one of two diametrically opposed nations battling to be the most powerful nation in the world. During this time period it was common to here the President of the US referred to as \"leader of the free world\".",
"The US is overwhelmingly the most powerful nation on earth. The President of the US is the most powerful person in the US. Therefore the President of the US, the most powerful person in the most powerful nation, is the most powerful office in the world."
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5o72j9 | How does tea get in water | So I intuitively understand why leaving tea leaves in water would change the flavor, but I'm confused about what's actually going into the water. Obviously I take the leaves out, so what is left in the water that leaves it colored and tasty? | Chemistry | explainlikeimfive | {
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"Compounds in the tea leaves dissolve into the water and/or particles of the tea leaves become suspended loosely in it. When you remove the tea leaves, you are not taking away everything you originally put in, but instead just stopping it from getting *too* much tea stuff in the water since the process takes time."
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5o7553 | How to treat wounds caused by shotguns? | Other | explainlikeimfive | {
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"dch3882"
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"text": [
"Just wanted to swing on by and say please call 911 if you accidentally shot a friend with a shotgun. You won't get prosecuted, accidents happen."
],
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5o75as | We can manipulate an organism's DNA to emphasize several traits. What would it take to make a DNA from scratch, creating an entirely new organism? | Biology | explainlikeimfive | {
"a_id": [
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"For some definitions of \"scratch\", we have already done this. We can build bacteria DNA from scratch, insert it into an existing bacterium, and have it use that DNA instead, building new bacterium as it divides. That synthetic DNA is mostly just a copy of the original bacteria DNA, but they did intentionally make changes. The real challenge is making truly novel DNA. We understand the letters and a few words, but we are still far enough away from understanding its language to do more than copy it.",
"Imagine you wanted to write a computer program that started with a few million lines of code, and the goal of this code was to mutate and branch out and write many different programs for different functions as well as being able to write the code that will allow it to re-write itself to reproduce and not just copy but re-write from scratch by inhibiting code that doesn't work, and expressing code that does work. Can you imagine trying to think that far ahead and how complex it would have to be, for all of those changes to take effect at just the right time and way to produce the result you desire? Our RNA and DNA evolved from trial and error over billions of years. Genes which did something useful, like create an amino acid that lets you get energy from sugar, or combine oxygen and carbon to get energy, are so useful that they are found in most of the organisms on this planet. But there were countless other ways to do this that were not as efficient, or for whatever reason were not as good as the current way to do it, and those genes got switched off or not passed on. You're talking about billions of years of random chance embracing improvements and withering away defects to arrive at an incredibly complex system that works, allows growth of an entire organism, including it's own evolving genetic material and reproduction. No human mind, no group of human minds, could possibly develop something so complex even if they had thousands of years to do it. A few hundred people can't compete with a few trillion organisms doing it for billions of years. We are like someone who cannot paint a classical masterpiece, but who can use photoshop to edit and change the way it looks without really understanding how it was put together. However, as our mastery of computer simulations and algorithms gets better, we may be able to create a simulation that produces random fragments of DNA, simulates what would happen to them, and applying evolutionary stress to them. You would start out with random nonsense, but the nonsense fragments wouldn't last and would fail, where as that one in a billion lucky chance that results in something useful would succeed. Running such a simulation at a very high rate of speed you can simulate millions of years of evolution in a human lifetime and we might find new genes from such a method.",
"URL_1 URL_0 \"Dr Venter's team developed a new code based on the four letters of the genetic code, G, T, C and A, that allowed them to draw on the whole alphabet, numbers and punctuation marks to write the watermarks. Anyone who cracks the code is invited to email an address written into the DNA.\""
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"https://www.theguardian.com/science/2010/may/20/craig-venter-synthetic-life-form",
"http://www.nature.com/news/minimal-cell-raises-stakes-in-race-to-harness-synthetic-life-1.19633"
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5o7mab | Why are circuit boards colored green as opposed to other colors? | Technology | explainlikeimfive | {
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"Nowadays you can find boards in many other colors other then green (black, white, red, purple, etc). As for why it has been green since forever there are some theories I found: Military requirement Consequence of the fact that originally the base resin was brownish yellow and when mixed with the hardener (muddy brown) you got green Best contrast between the solder mask and the white legend (the background and the text on the board) Most visible color to the human eye If I had to guess it's probably a bit of all of the above and companies stuck to the color until there was more demand for some variety"
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5o7vux | Why is it illegal to pump your own gas in Oregon? | Other | explainlikeimfive | {
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"text": [
"It's due to a 1951 law which was created for reasons of safety. Remember that in the early days of automobiles, nearly all service stations were full service (i.e. had an attendant to pump). So as more stations began to allow people to pump their own gas, some people got worried. As to whether it's really safer or whether it's just a way to create jobs, well, probably just the latter."
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5o83kp | Why is it "half an hour" instead of "half a hour" | Other | explainlikeimfive | {
"a_id": [
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"text": [
"Whether you use \"a\" or \"an\" is determined by if the sound of the first syllable of a word is a consonant or a vowel, not if the first letter of a word is a consonant or a vowel. Most of the time the two will be the same, but sometimes (particularly with words that start with \"h\") the consonant is silent and the first syllable is a vowel sound. Words like \"hour\", \"herb\" (american pronunciation), and the like get \"an\". Words like \"helicopter\" and \"hair\" get \"a\".",
"Even though 'hour' begins with a consonant, it makes a vowel sound- 'ow'. That's why we also say 'It's *an* honour' not 'It's *a* honour'."
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5o87le | How do NFL players play in such cold temperatures without any thermal wear without getting hypothermia/sick? | So, I'm seeing all these guys playing in freezing temperatures with no Under Armour/thermal wear on under their jerseys. Just seems so unlikely that they're out in such temperature for so long without having any immediate serious health effects. I mean, the obvious answer seems to be that they're doing physical activity and thus are creating heat, but football is a largely anaerobic sport that is very start-and-stop in its nature. Are guys really going that hard on each play that they warm up in a few seconds or am I missing something? Do they get sick between games and we just don't know about it? Been on my mind a bit recently, hope someone here can help me sort it out! | Other | explainlikeimfive | {
"a_id": [
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"Being cold doesn't get you sick. Cold/flu during the winter is common because people tend to be indoors and therefore closer to each other. (at least as far as I know) As you noted NFL players are mostly standing around, for example the current game, Kansas City vs Pittsburg @ KC is currently 33F. While cold, not so cold that player on the field will experience hypothermia in the short time they are on the field. On the sidelines, depending on the weather conditions, they may be standing/sitting near [propane or natural gas heater/blowers]( URL_2 ), use heat packs, and get covered up in [full length parkas]( URL_1 ). See also: URL_0",
"They do wear blanket or sit near heaters when not on the field. And they probably do wear thermal underwear, you just do not see it, or do not recognize the custom-made stuff that they wear."
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5o8f8e | How come sometimes we can feel our heartbeat in random parts of our body? | Biology | explainlikeimfive | {
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"text": [
"The pulse? caused by cycling changes of blood pressure as blood flows in the arteries. Commonly felt on the wrist, neck, upper arm, and sometimes inner thigh.",
"Our mind usually ignores sensory information that is somewhat permanent or persistent. The brain is specialized to recognize changes. For example: we don't see our nose when we have both eyes open although it is right there in our visual field, or hear our blood rushing through our veins. The same applies to our heartbeat. At a constant rate, we usually don't recognize it. We start noticing it, when it tends to become unusual high/strong/irregular. And since our heart is basically a pump, that pushes blood through our body, we theoretically can feel the heartbeat everywhere in our body ... given that the heart rate changes significantly, so our brain recognizes the change or the part is more sensitive due to an injury (like a burning or sth. like that)."
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5o8f8u | If I rewatch a TV series how is it I remember the start more than the end even tho it has been longer since ive seen the start? | Other | explainlikeimfive | {
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"This is a psychology thing! It's called the primacy effect, and is part of the serial position effect. Whenever you have a list of things, there are three things you are most likely to remember--the beginning, the end and anything out of place. An example list: mango apple banana orange velociraptor peach apricot The beginning has more time to be settled in your brain than anything else. When you are on the apple, your mind's focus is split between apple and mango, and soon you think about banana. Mango had time all to itself, where the brain necessarily thought only about mango, while apple had no such luxury. This \"split\" focus gets worse as the list progresses.",
"Because you spend a lot of time remembering the start, which embeds it further in your mind. As you watch the series, and things happen based on previous events, you remember the previous events. Of course one of that happens for the end of the series, so it never has time to properly make it into long term storage."
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5o8idn | Can you really not catch a cold from being cold? | Biology | explainlikeimfive | {
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"text": [
"You catch a cold by getting a virus. Cold can suppress your immune system and make you more susceptible to getting sick, but cold by itself cannot directly make you sick. You have to be exposed to the cold virus to get a cold.",
"The cold is a virus. If you are not exposed to the virus you can not catch it. In some studies, cold weather have shown a slight decrease in immune systems while being cold. However, in cold weather, more people spend time indoors in close quarters increasing close contact with those that may be sick."
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5o8irn | why do restaurants as a whole have an atrocious failure rate, but chain restaurants consistently stay open? | It's common knowledge that the vast majority of restaurants fail, and most in their first 1-2 years open. And yet, chain restaurants - Chili's, Olive Garden, IHOP, shit like that - not only open new locations all the time, but they usually manage to stay open. Their failure rate isn't anywhere near the independents. Obviously, a chain has some cost advantages with supply and ads/marketing. I get that. But that can't be all it is, right? Is it premium locations? Management skill? Something I don't know about? | Economics | explainlikeimfive | {
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"Have you ever made cookies from scratch before? I have, man sometimes it just doesn't work out. Other times its great and works perfect, its not a super easy thing. Now, but when I make them from those tubes of premade cookie batter and they give me all the instructions and stuff, they always come out just right A chain restaurant is like that pre-made cookie dough. Its a pre-set package, that we already know it is successful, it doesn't require a lot of ingredients or knowledge or skill to make, you just buy the package and you're all set for a good experience at a very reasonable rate, other people have already figured it out before you, and you just have to bake the cookies is all, and they even tell you how!",
"My sister and I considered opening a restaurant. We had a menu, a business plan, and a three-year financial prediction/goal. Eventually we decided against it, but in the process I learned some very interesting things. **People who start up restaurants don't know jack SHIT about running a restaurant!** Most people who open a restaurant start with some recipes. That's fine, but then you have to consider (just off the top of my head here)... 1) How do these recipes scale up to 20-50x? (Not everything works linearly!) 2) How much food am I wasting? A few scraps when preparing food for your family is fine. Those same scraps on every dish for a few hundred meals a day add up very fast! 3) How much do I need to earn per hour per seat to turn a profit? 4) How much will my kitchen cost? Most people have no IDEA how expensive commercial kitchen equipment is, nor do they know that it can almost all be had for half price or less at auction, because of so many other failed restaurants. 5) How am I going to market it, and what's my timeframe to get a certain sustainable customer base? 6) Pricing as a function of all of the above! 7) Menu planning/design. This makes far more difference than people think. 8) How will I deal with special requests, kids, and so forth? Obviously the huge chains have cranked the numbers on these variables and also have a huge name brand recognition to leverage. They know how to make it work, and make the local franchisee successful."
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5o8msh | Why do you feel so much worse in the morning and at night when you're sick? | Biology | explainlikeimfive | {
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"text": [
"Would have thought it's due to diurnal (as in varies throughout the day) variations in cortisol. Cortisol is a natural steroid hormone (glucocorticoid) produced by the adrenal gland. It has functions which relate to the sleep wake cycle and also acts as an anti inflammatory (it also does a load of other stuff that's useful but potentially unpleasant- google Cushing's syndrome). It varies throughout the day. When you get sick it's the release of substances called inflammatory mediators that make you feel crappy. These substances are necessary as immune signallers (the immune system talking to itself \"go here: pathogens\" and to the rest of the body e.g. causing increased blood flow to infected areas and allowing immune cells to pass through the walls of blood vessels). When you get a systemic infection these basically flood everywhere and can make you feel awful. Cortisol (as with other glucocorticoids) dampens down the immune system and reduces this (as do the so-called Non-Steroidal Anti Inflammatory drugs like ibuprofen, though they do it in a different way). This effect also explains why asthmatics tend to be worse in the morning and at night as well, as their symptoms are related to immune hypersensitivity in the bronchial tree. I'll spare you the explanation of the pathophysiology of asthma, but trust me. Source- UK Based Anaesthetist/Intensive Care Doctor. Been in the medical profession going on 7 years.",
"Most likely it's partly from elevated levels of your parasympathetic system (\"rest and digest mode\") in the morning and evening and the opposite during the day when your sympathetic tone (\"flight or fight\") increases. These signals change a wide range of physiological changes in your body that are more noticeable when you are compromised. For example, there's nothing to get you to forget about your cold when you wake up late for work."
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5o8t0m | Why does your lip quiver when you are about to cry? | Biology | explainlikeimfive | {
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"text": [
"The acute stress reaction (sudden, extreme anger, frustration, grief or excitement) often leads to neurogenic tremors. It's not just your lip, but many other parts of your body start to quiver -- worsened when initiating movement. In this case, your mouth might quiver because you want to talk. In anger, you notice your hands might also start to quiver if you want to hit something. Often it's just involuntary and your legs may even give way.",
"There are libraries of information on this topic! So interesting! This is my favorite topic in psychology, but I'm not at home, or I would end up taking two days to reply! This is a subject that actually predates psychology. Darwin says that facial expressions are universal (he tested this by having missionaries conduct surveys all over the world). All cultures share a core group of expressions. Some psychologists say there are six universals: Ekman/Friesen/Shaver, some say three-Field; Plutchik says eight, Izard says ten, Feleky says 86 universal emotional expressions! Darwin also said that emotional expressions fulfill an evolutionary purpose. When you smell something disgusting, you open your mouth and stick your tongue out in a wide manner--like a spout. Even though you are smelling something gross--you automatically react physically like you are spitting out something gross. As we get older, we can control it better by not sticking our tongue out or opening our mouths--but we still flare our nostrils--like we're preparing to make that face. Blind children do these expressions, as well as isolated cultures--this indicates that facial expressions are native. The trembling of the lip is associated with sadness or often pouting. Native children were studied by Darwin (his savages) and he found, that just like his own children, they protrude their bottom lip when they're sad--but as they grow up--stop doing this. The evolutionary need, it has been speculated, is that the child is signaling the need for a breast to feed! So when our lip trembles, it may be a remnant of that response. But of course--some believe the total opposite. Zajonc (and Waynbaum) believed that expression actually CAUSED the emotion by manipulating facial nerves and cranial blood flow.",
"> When you cry, there’s a momentary loss of composition of your face. It’s somewhat disturbing to experience. When we lose control of our usual symmetry and calm, that could be frightening. The muscles in your face tense up and cause the shaking shivering quivering, and naturally, you turn into this: URL_1 [Source]( URL_0 )"
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5o8vh8 | Why can't we make our fingers limp when we relax them? | Biology | explainlikeimfive | {
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"text": [
"You can make them as limp as the joints and ligaments allow. Your fingers are actually connected to muscles in your forarm which control them by ligaments that run through your hands, and those have a certain basic tension.",
"Same reason you spine doesn't completely fold over when relaxing. Your fingers are composed of several bones and muscles just like your spine. When relaxed your fingers will fall into there natural position but not completely go limp"
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5o93sp | Why do we sing in the shower? | Other | explainlikeimfive | {
"a_id": [
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"text": [
"Bathroom singing, also known as singing in the bathroom, singing in the bath, or singing in the shower, is a widespread phenomenon. Many people sing in the bathroom because the hard wall surfaces, often tiles or wooden panels, and lack of soft furnishings, create an aurally pleasing acoustic environment."
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5o99qw | what are birthmarks and why do they appear? | Biology | explainlikeimfive | {
"a_id": [
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"text": [
"A birthmark is a congenital, benign irregularity on the skin which is present at birth or appears shortly after birth, usually in the first month. They can occur anywhere on the skin. Birthmarks are caused by overgrowth of blood vessels, melanocytes, smooth muscle, fat, fibroblasts, or keratinocytes.",
"They are deposits of melanin in the skin, similar to freckles or moles. They are formed along with the rest of the epidermis around 14 weeks.Birthmarks are areas of discolored skin that are on a baby's body at birth or that show up within a few months after delivery. Over 80 percent of babies have some kind of birthmark. Some endure for life, while others fade away over time. Most birthmarks fall into one of two categories: vascular or pigmented. Vascular birthmarks are caused by blood vessels that have accumulated below the surface of the skin. They range in color from pink to red to bluish, depending on the depth of the blood vessels. Pigmented birthmarks — usually brown, gray, bluish, or black — result from an abnormal development of pigment cells."
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5o9jbr | how does a cancer like breast cancer kill the host? | Biology | explainlikeimfive | {
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"text": [
"Cancer is basically uncontrolled reproduction of cells. The cells in your body all have a job and a timeline. So for example, and this is not an actual number, but a bone cell will replicate itself 10 times and then it dies. Or if it gets damaged it sends out a signal to other cells \"hey! I'm not going to make it!\" And it's broken down and absorbed by the body. Cancer starts with a single mutated cell that replicates and replicates and now you have a tumor. It's a damaged cell but it doesn't send the \"kill me now!\" signal. And that tumor just grows and grows and develops more mutations that allow it to get nice and cozy where it's at. At a certain point it gets the body to send it blood with it's own system of vessels. Then pieces of it travel through the blood or lymphatic system and nestle in and grow more. This is called a metastasis. These growths put pressure on the tissue, organs, etc around it. They also steal blood from the surrounding tissue. And it's completely unregulated because the body thinks it belongs there. Because it's made of your own cells. So it just takes the resources your body needs and pushes your organs and tissue out of the way to make more room and takes more blood and more nutrients while destroying functional tissue in making room for itself.",
"Breast cancer, even after apparently successful treatment, often spreads to other areas of the body. This is called metastasising. The cancer in the areas it spreads to is usually the main cause of death.",
"In the beginning stages of many breast cancers, the cancer cells are contained in a limited area like the milk ducts. If left undiagnosed and untreated though, the cancer can spread. In an ideal treatment, there would be a single tumor in a non vital area that could be easily removed. In an un-ideal situation there are many tumors spread throughout the body and manually removing could kill the patient, or is otherwise not possible. In the case of breast cancer, the cancer cells can spread to the rest of the body (Metastatic breast cancer), growing new tumors. This not only makes it harder to treat, but depending on where those tumors grow, it can be deadly. For instance imagine one growing in your liver or lungs, or even your brain. It could damage the organ and cause organ failure. The organ failure in turn leads to a painful death as the organs shut down and the body slowly dies."
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5o9uke | If exercise makes your heart beat faster, how come it lowers your heart rate eventually? | Other | explainlikeimfive | {
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"text": [
"Think of it as a muscle, like it is. A weak muscle has to work harder to accomplish a task, whereas a strong muscle doesn't have to work as hard. Your heart beating quickly while under no strain will not change. Put your heart under strain repeatedly and it will strengthen to accommodate that strain, and while under normal use it will work more efficiently and beat slower. Like your brain. Without use, it'll work harder when called upon. When used regularly, it will strengthen and while at rest it will be more capable of instantaneous requirement. Applies to anything really."
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5o9vqp | What's the difference between just resting (closing your eyes, not moving) and actually going to sleep? | The difference in both what goes on, and the benefits reaped from doing so. | Biology | explainlikeimfive | {
"a_id": [
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"text": [
"When you are in a deep sleep, [your body is regenerating]( URL_0 ). It's synthesizing proteins and repairing stressed muscles, while your brain is sorting and consolidating the information it received throughout the day. To do this, your body generates a wave of a hormone called melatonin which turns some areas of your brain off. Your body goes through various cycles of sleep (REM, NREM stages) in order to complete these tasks, and it can't happen while you're awake. Certainly laying very still and calming your thoughts, more of a form of [meditation]( URL_1 ), would have beneficial effects on your body and mind (far more than freaking out about how you will function tomorrow having been up all night). Meditation can help improve your sleep by training your body to release more hormones, but it is not a substitute for sleep.",
"Just closing your eyes wont send you into REM, REM is a state necessary to heal the self and most of the body's re engineering happens during REM."
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5o9zhx | That wub wub sound when you shake a flat piece of metal | Other | explainlikeimfive | {
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],
"text": [
"I'm not sure what there is to explain here. When objects are moved through the air or vibrated they generate a sound wave. If you are close enough to hear the sound, you hear it."
],
"score": [
8
],
"text_urls": [
[]
]
} | [
"url"
] | [
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] |
|
5oa6cg | How can apps like Discord and Skype afford to provide their services for free? | Economics | explainlikeimfive | {
"a_id": [
"dchrqi9"
],
"text": [
"URL_0 > Skype is based on a freemium model. Much of the service is free, but Skype Credit or a subscription is required to call a landline or a mobile phone number. URL_1 > While the software itself comes at no cost, the developers are investigating ways to monetize it, with possible options including paid customization options such as emoji or stickers.[3] On December 23rd, 2016, Discord posted on their blog that they are eventually adding a way for people to support them using Discord Nitro.[8] This is told to have Custom Emotes usable on every server, GIF Avatars, and more.[9] Currently, Discord Nitro is only available to Australian users for testing. (TL;DR Discord isn't making any money yet)"
],
"score": [
16
],
"text_urls": [
[
"https://en.wikipedia.org/wiki/Skype",
"https://en.wikipedia.org/wiki/Discord_(software)"
]
]
} | [
"url"
] | [
"url"
] |
|
5oad3j | Why do trees give fruits instead of just dropping the seed like flowers? | Biology | explainlikeimfive | {
"a_id": [
"dchso2j",
"dchstnl"
],
"text": [
"If it drops seeds then the new tree will be in direct competition with the parent tree. If it can convince other animals to carry its seeds far and wide it passes on its genetics without having increased competition.",
"Every species wants to conquer the world. They evolved different ways to spread their seed all over the place (hahahaha). Most flowers use the wind to their advantage. Trees often use sweet fruits with the intention that birds will eat it together with the seed and literally drop the seed elsewhere. But there are ofc trees without fruits, they can also use the wind, or even insects to transport their seeds/pollen to fertilize it with other trees. But there are even many more different ways plants reproduce. Beauty of nature."
],
"score": [
14,
8
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
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|
5oah3o | Solar panels. How do they work? | Technology | explainlikeimfive | {
"a_id": [
"dchu1xn"
],
"text": [
"The sun creates these things called *photons*. These photons are little packets of light and energy. These are ejected from the sun trillions and trillions of time per second. When photons hit things, they can give up their energy to them. That's why light can heat things up. Solar panels take this energy and store it. The main mechanism is called the *photovoltaic* effect. Solar panels have a crystal panel that the light shines on, and inside there is a lot of circuitry which is connected to a battery or energy storage device. The crystal panel is made up of atoms. Atoms are composed of their cores, and the electrons which orbit them. The cores, assuming they have at least one proton are positively charged. To even out the charges so the atom is neutral, negatively charged *electrons* surround them. They \"orbit\" the atoms at different energy levels. Getting into this area any further ultimately leads to quantum mechanics and things get a little too wishy washy and mathy to do a good ELI5 on it. If a photon hits the orbit of an electron, the electron could take that energy from the photon and *excite* and go up an energy level. Now the solar panel has *captured* the energy from the sun. This happens all over the solar panel. This is where the *photovoltaic* effect kicks in. The crystal panel's exposure to light (because of how it can capture energy to excite electrons) causes a *voltage* change, and can cause an electric current in the circuit. This causes energy to flow into a battery and we can store it for later. Edit: Thanks for the suggestions /u/TBNecksnapper"
],
"score": [
99
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
5oal0y | Why is NATO obsolete? | Other | explainlikeimfive | {
"a_id": [
"dchukf7",
"dchu5pb",
"dchu192"
],
"text": [
"NATO was originally formed to oppose the Russians. The Russia have changed a bit since then and really would like NATO to stop opposing them from for example annexing some errant Baltic republic so they tell everyone that there is no more need for NATO. Russia telling you that NATO is obsolete is like thief telling you, you don't need to lock your door.",
"NATO, or the North Atlantic Treaty Organization was put in place after World War 2 to protect countries around the north Atlantic (=The US and it's European allies) from Soviet aggression, which was a very real threat. Many countries from around the world have since joined NATO, not all of which were threatened by the USSR, and the mission has been expanded to include other threats besides the Soviet union as a result. Since the USSR is now dead, the original mission cannot be completed, and some feel that NATO now has no purpose. Personally I think that there are plenty of threats to western democracy, islamic terrorism being #1, and an international association such as NATO is invaluable in coordinating efforts.",
"NATO was formed for mutual defense against the USSR which at that time controlled Russia and the communist nations of Europe. Now it is gone and those nations are free. East Germany and West Germany is united. But Russia is led by a militaristic leader who uses his military outside its borders conquering Crimea, supporting Assad and in general being a threat. We should not be too hasty."
],
"score": [
7,
7,
5
],
"text_urls": [
[],
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
5oan5c | What does a university accreditation do? | Other | explainlikeimfive | {
"a_id": [
"dchuchg",
"dchxizg"
],
"text": [
"Accreditation for a university says \"this place doesn't just SAY it provides a university-level education -- it actually does so, as validated by a jury of its peers. You can trust a degree from this place to have covered the usual topics, be graded at the usual level of difficulty. This is *not* a scam or a place where you can just buy your degree and not learn anything.\" Accreditation is what separates schools that advertise in the back pages of magazines from places which hire PhDs.",
"An accrediation can almost be thought of as a product guarantee. The university or college has proven that it provides a product (degree, masters, doctorate, etc) that has met/exceeded all of the standards set fourth by either an industry or educational counsel. This process is extremely detailed and evaluates every portion of the university's/college's program; from the cirriculum, to the professors, to servcies provided. Some of the evaluation process can be performed before the program is started; however some accrediation processes are not completed until at least one graduating class has passed through the program. A little more indepth, but [here is a rubric]( URL_0 ) that was recently used for a nearby College of Pharmacy during their accreditation process."
],
"score": [
9,
3
],
"text_urls": [
[],
[
"https://www.acpe-accredit.org/pdf/Rubric2016Guidelines1.0b.pdf"
]
]
} | [
"url"
] | [
"url"
] |
|
5oaoc2 | What's the difference between Agnostic and Atheism? | Other | explainlikeimfive | {
"a_id": [
"dchumy9",
"dchvjq5",
"dci5932",
"dchv7t9"
],
"text": [
"Gnosticism is a claim of knowledge. I know things for certain if I am a gnostic. If I am agnostic, I admit I don't have a solid basis for my knowledge, but feel it is correct. Theism is the belief in a god. Theists believe there is one. Atheists aren't convinced there is one. Antitheists are the ones who say god does not exist. So I can be a gnostic theist for instance. I know there is a god. I can be an agnostic theist. I believe there is a god, but I cannot state for certain why I believe there is. I just feel there is one. I can be agnostic atheist. I don't know enough to believe in a god. Or a gnostic atheist. I know enough that I cannot believe in a god.",
"A lot of people in this trend didn't really got the definition of Atheism right. Atheism ISN'T that they know there is no god. Atheism is the disbelieve in the claim that there is a god. An atheism could or not believe that there is no god, but all atheism don't believe that there is. It's the default position toward the god claim until you receive enough good evidence that god exist.",
"In modern parlance and most widely accepted definitions, \"Atheism\" is a term that describes the state of not believing in any gods. A person is either \"Theist\" (believe in gods), or \"Atheist\" (not a theist). Someone who has never heard of the concept of gods is \"Atheist\" by default. \"Agnostic\" is not a term that necessarily applies to religious belief (though most commonly does). It basically means \"Cannot be known\". It is the philosophy that there is always the possibility of being wrong about something, so nothing is 100% certain. In terms of religion, it means that we cannot know for sure whether or not a god exists. A person can be agnostic while still believing certain things exist however, as belief does not require certainty. Agnosticism is just a logical acceptance of the nature of knowledge and the fallibility of human perception. Most people who openly identify as \"Agnostic\" in terms of religion are more specifically \"Agnostic Atheists\". Many people who identify as religious are more specifically \"Agnostic Theists\".",
"Agnosticism is that you believe the question about god is not answerable Atheism is that you think there is no god. You can combine the two **Agnostic Atheist**: We can't prove or disprove god, i don't think he exists. **Gnostic Atheist**: We can disprove god, God does not exist. **Gnostic Theist**: God can be proven to exist, god does exist. **Agnostic Theist**: We can't really prove god exists or not, but i do believe he exists. And there's all kinds of thought experiments and philosophies regarding each of these, for example, [russels teapot]( URL_0 ) is an argument for agnostic atheism. (just cause we can't disprove it, doesn't mean it exists. )"
],
"score": [
85,
12,
7,
5
],
"text_urls": [
[],
[],
[],
[
"https://en.wikipedia.org/wiki/Russell's_teapot"
]
]
} | [
"url"
] | [
"url"
] |
|
5oaoun | Countries and debts. Is this even real? | USA, Germany,... all these countries are in debt. My questions: 1. To whom? 2. Why not cross out the mutual debts? 3. Some lender must be tremendous rich (on paper)? Please help :D | Economics | explainlikeimfive | {
"a_id": [
"dchvixn",
"dchvy89"
],
"text": [
"Governments create debt by selling \"bonds.\" These can be bought by anybody, but it's usually businesses and banks and investment funds. There's usually no such thing as mutual debut. If I borrow a tenner from you, and you borrow a tenner from me, then effectively I have paid you back. In practical terms, this sort of thing can happen, because debt is often done on a fixed term basis, and aside from anything else, the paperwork would be more hassle than it's actually worth. edit: imagine, if you have a savings account and a credit card from the same bank..... why don't you just pay the credit card with the savings? I don't know about \"tremendously\" rich, but yes, lending money to governments or anyone else is profitable (as long as it is paid back). That's why people lend money. But, in simple terms, if you've got £10000 lying around doing nothing, you are better of investing it (i.e. lending it to someone) and getting back £11000 a year from now, because if you just stick it under your mattress instead, it will actually lose value.",
"It's not as though the money is so simple as \"USA owes Germany 5,000 dollars, Germany owes the USA 4000 dollars, let's cross it off and say USA owes 1000\" or what not. Rather, every government is made of many many organizations. The different groups may owe money to one another, or may owe money to the citizens, or to programs like social security. Just as an example, the majority of USA debt is owed within the USA, not to other governments."
],
"score": [
9,
6
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
5oapam | Is it okay to leave your phone (or other electronics thay require charge) plugged in and charged overnight? | Technology | explainlikeimfive | {
"a_id": [
"dchxbhe"
],
"text": [
"No, it actually prolongs the life of the battery. Once the battery is full, the charge circuit will cut power to it and not charge it again until the battery voltage drops by some amount. However, while your phone is plugged in, modern phones will not draw any power from the battery and rely purely on the external power. This basically means your battery is not being drained for those remaining hours. Battery lifespans are typically measured in the number of full charge-discharge cycles, so by keeping your phone on charge for a few extra hours a day, you're saving those hours from the lifespan of the battery."
],
"score": [
4
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
5oavx3 | How do blisters form? And whats in a blister? | Biology | explainlikeimfive | {
"a_id": [
"dci652b"
],
"text": [
"Living tissue, as a general rule, is wet. Living cells like being wet and generally require a fluid environment to function. Many living things have to stay constantly wet or they simply dry out and die (or go into stasis). So human beings are just a large collection of cells, the vast majority of which are constantly bathed in fluid which they require to function and live. We have a few specialized cell types which exist specifically to form a barrier between our living cells and the outside world. In humans this is primary skin and mucosa. Broadly speaking skin covers the outside of your body, mucosa lines the inside. Let's set mucosa aside for a moment. If you damage, break, cut or scrape your skin, the protective barrier is broken, and something will leak out. Obviously blood, but that will clot off after a while. Without intact skin all tissues will leak serous fluid even if there is no bleeding. Now this can dry out and form a crust or scab, but if you keep it moist it will produce fluid indefinitely until (hopefully) new skin heals over it. Some tissues don't produce enough fluid to survive exposure for extended periods, and they die (bone, tendon, and ligament being notable examples). Usually people don't notice this fluid because blood predominates, unless they pick at a scab or have an open wound. A blister forms when the skin is damaged but the top layer of keratin, (\"dead skin cells\", though that's not really a great way to think of it) stays intact. The top layer of your skin is actually pretty tough, so you can kill or damage some of the living skin cells underneath, while having top layer stay in one piece, say through through friction or a burn. Since the skin isn't doing it's job anymore the exposed cells underneath start producing fluid. If the skin is dead but still intact on top it collects and forms a blister. If not you just have an abrasion/wound. Note that enough physical trauma to damage the skin is usually enough to create defects in your epidermis. That's why blisters are most common on areas where the skin is particularly robust (hands and feet) or when you have burns (can be severe damage that doesn't break the skin). That's the 5 yo version anyway."
],
"score": [
14
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
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