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5wkgi0 | What's up with wannabe sneezes? Why do they appear and dissapear without the act of sneezing? And why do they feel so unsatisfactory? | Biology | explainlikeimfive | {
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"Sneezing is usually triggered by irritation of the nasal mucosa (tissue in your nose). When this irritation occurs it sends signals to parts of your brain to say \"we're being irritated\". If enough of these signals are sent, your brain will say \"ok time for a sneeze\" and sends signals to the parts of your body responsible for sneezes. If there aren't enough of these signals then your body doesn't trigger a sneeze to occur. This is so weird feeling because your body has to fix the irritation internally, which usually takes longer and so you are irritated for longer. TL;DR: wannabe sneezes happen because your nose is getting irritated, but not irritated enough to trigger a sneeze PS: if you feel a sneeze coming and want to sneeze faster, stare into a source of light and blink really fast"
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5wkhiq | I heard that the world is $217 trillion in debt. Who are we in debt to? | Or is it every country's debt added up together? And do countries forgive debt for a country that they also owe money to? | Economics | explainlikeimfive | {
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"That is a rough figure for all of the debt in the entire world. National debt, private debt, etc. The federal deficit, your credit card balances; the grand total sum is $217 trillion. It is owed to everyone and anyone who is a creditor. Nations owe other nations, businesses owe other businesses and banks, etc. That is roughly 30% of the *total GDP*. Which means the world still produces 70% *more* than it owes. Reduced down to tiny numbers, it would be the same as if you *owed* $30,000 dollars total in debt, but made $70,000 per year salary. It isn't ideal, but you're in a good position when your income outweighs your debts and you can easily pay it.",
"Let's say I'm a government, and I have great credit because I haven't defaulted in 250+ years. I can sell 30-year bonds at 3% interest and people will actually buy it! This counts as debt, because I have to pay those bonds back with the interest I promised. But by using that loan to invest in myself, I can make 5% on it. People wanting to guarantee a small return reward me for my reliability, by giving me money that I can turn into a larger return. I'd be the biggest moron in history for not selling bonds.",
"> And do countries forgive debt for a country that they also owe money to? Generally speaking, governments tend not to directly owe other governments that much money. Debt is primarily owned by individual citizens and businesses, and overwhelmingly it's owned by individuals and businesses within the same country that owes the money to begin with.",
"Would there ever be a way in which all this debt could somehow be completely payed off?"
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5wkoy4 | Gravity's effect at long range? | Does gravity have an infinite or finite range? If you were to place two hydrogen atoms 10 Light Years apart from each other, with no other objects around to interfere with each other's gravity, how long would it take for gravity to pull them together? | Physics | explainlikeimfive | {
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"Yes, gravity has infinite range. But because the universe has a finite age, there may not have been enough time for two things to gravitationally interact, however. So practically speaking, gravity has a finite range. Let's consider your example: According to Newton, gravity follows an inverse square law, meaning the force is proportional to one divided by the distance (d) squared. The force is also proportional to the product of two masses (m1 & m2) which are interacting. In equation form, the force is F = G\\*m1\\*m2/d^2 . G is the universal gravitational constant, something built into the fabric of the universe, and has a value of 6.67\\*10^-11 N\\*m^2 / kg^2. (N is the unit Newtons for force, kg is kilograms). So by Newton's equation, gravitational force can't be 0 until you've gone an infinite distance away. The mass of a hydrogen atom is known to be 1.67\\*10^-27 kg. If there were two of them separated by a distance of d = 10 light years = 9.46\\*10^16 meters, then Newton says the force of gravity between them is 2.08\\*10^-98 N. Newton also famously said force equals mass times acceleration, or F=m\\*a. Rearranging so that a = F/m, one of the hydrogen atoms experiences an acceleration of 1.245\\*10^-71 m/s^2. That hydrogen atom has to travel x = 5 light years to meet the second hydrogen atom in the middle of their 10 light year separation. That second hydrogen atom experiences the same acceleration as the first due to symmetry. Newton also gave us the equations of motion. He said that x=0.5\\*a\\*t^2, where x is the distance traveled by any object, starting from rest, undergoing constant acceleration (a) during some time (t). Rearranging, we find the time is t = sqrt(2\\*x/a). With x = 5 light years = 4.73\\*10^16 meters, the total time for the hydrogen atoms to be pulled together is 8.7*10^43 seconds. That's 2.78\\*10^36, or 2.78 undecillion, years. To compare, the universe is only 1.4\\*10^10, or 14 billion, years old. So you would need to wait almost 2\\*10^26, or 200 septillion, times the current age of the universe for those 2 hydrogen atoms to come together. So in the current life of the universe, two lone hydrogen atoms haven't had enough time to be gravitationally attracted to each other. Forces also propagate at the speed of light, so it would take 10 years for one hydrogen atom to even start feeling the force from the other hydrogen atom. However, I neglect this in my calculation since 10 years is insignificant compared to 2.78 undecillion years."
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5wkuv0 | How do Landline phones work when the power is out? | Technology | explainlikeimfive | {
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"A standard landline (POTS) has -48V DC power included with the signal. The phone company central office also has a bank of batteries to operate when the power is out.",
"The Central Office for the phone system supplies power down the lines for the phones. It's DC (direct current, like a battery) and the voltage varies based on what the phone is doing. When the phone is on the hook, the circuit that goes between the Central Office (Henceforth the \"CO\") and your phone is open - no current flows. One wire of the pair going into your phone is always connected to the CO, the other wire is connected when you pick up the phone. (While I'm thinking about it, the wires are called the \"Tip\" and the \"Ring\") When you pick up the phone, and get a dial tone, you're supplied with, I think, 10 volts DC. You keep that 10VDC when you are talking. When you make a call, I think it jumps up to 48VDC, until you answer it."
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5wkzcp | Why are eye colors so varied but all pupils are solid black? | Biology | explainlikeimfive | {
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"The color is in the iris which is the adjustable muscle around the opening. The pupil is actually an opening behind the clear coverings of the eye, so it's actually a hole. That's why it's black",
"I believe what you're referring to is that the iris consists of two layers - the epithelium and the stroma. The epithelium lies deepest and is black in all people. In fact, when people have black spots on their iris, that is the epithelium peeking through. The stroma is what gives the eyes their color. The stroma mainly consists of colorless collagen. Some eyes have melanin in the stroma, and the degree of melanin regulates whether the eyes are dark brown or lighter brown. Next, let's look at blue eyes. They contain neither collagen nor melanin. In reality blue eyes are colorless. What we see as the color blue is in fact structural, and not pigmentation. The cells in the stroma scatter the light so that it looks blue. It's called the Tyndall effect, and is essentially the same as the Raleigh effect that makes the sky look blue. Green eyes are a half-way house. They are structured like blue eyes (no collagen) but have a little bit of melanin. The melanin creates light brown and the structure creates the same scattering as in blue eyes, and the net effect of the two is what looks like green. So, the difference in color is really just the amount of melanin (or none) and the presence (or not) of collagen. There is a lot of speculation about the genetic trait that removes collagen - some say it may be a neanderthal inherited trait, others that it is one or more mutations.",
"The pupil is an opening to allow light in. The coloured iris is a muscle that contracts and expands to control the amount of light we let in. [Wiki]( URL_0 )"
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5wl1rl | What do astrophysicists understand with certainty? | any idea? | Physics | explainlikeimfive | {
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"Basically the only thing astrophysicists know for sure is the stuff they can directly observe and the stuff they can prove with observations or calculations. For example we know for sure the universe is expanding because we can actually see everything moving away from us. What we don't know is exactly how, because we can't see what is physically pushing things away. By all means gravity should be pulling things together and things should be moving the other way. But the observations say that everything is moving away so we know for sure that SOMETHING is pushing everything away from us."
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5wl6n4 | Why do average temperatures follow a sinusoidal wave? | I've graphed a cos wave on top of the average temperature data for Toronto, and I was astonished to find how close the temperature is to a sinusoidal function. Why is it that the average temperature follows a cos/sine wave so closely? Why isn't it something else, like a triangle wave, and why isn't it more random like I expected? Here is the graph with the points: URL_0 | Physics | explainlikeimfive | {
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"The x-axis here most likely represents months (since each cycle has a length of 12). So what you are seeing is the temperature fluctuations that occur from summer to winter as the earth orbits around the sun. Sinusoidal functions can be derived from [circular motion]( URL_0 ) so patterns like this one are very common in situations involving orbits.",
"If you turn on a light in the top of the room and hold out a piece of paper horizontally then it'll cast a shadow. Angle the paper a bit and the shadow gets smaller. Angle it more and it gets smaller and smaller until you're holding the paper upright, at which point there's virtually no shadow at all. The bigger the shadow, the more light (and therefore energy) the paper is absorbing from the light. The surface of the planet works the same way. At noon on the equator on an equinox the equator is very much like the horizontal paper, absorbing as much sunlight as possible. Meanwhile the poles are very much like the vertical paper, absorbing very little sunlight at all. If earth's axis of rotation was perfectly aligned with the orbit then any given location would always be at the same angle relative to the sun (when measured at noon; it obviously varies throughout the day). However, the axis is *not* aligned, which means that during some months a location may be more like the equator and other months it's more like the poles. This is where the seasons come from. When you look at how big this effect is you bring in the planet's position in the orbit which is mostly circular. When working with circles sines and cosines pop up all over the place; getting into the math of actually deriving the solar intensity would be beyond the scope of ELI5. The final piece of the puzzle is that solar intensity is the single biggest non-constant effect in determining temperature. It's not the only effect, of course, and it's not perfectly linear nor is the orbit perfectly round and so on, but it's close enough that a sinusoid is going to be by far the closest simple fit to the data."
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5wlb7e | Why do fish oil supplements cause belching? | It just seems gross that something that is supposed to be beneficial to one's overall health causes such a nasty side-effect. But, why is that so: why does fish oil cause people to belch the fish taste back? Is there anything that can stop that side affect from occurring? | Biology | explainlikeimfive | {
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"I'm just going to answer your question about how to avoid the belching. They make burpless fish oil capsules which prevent that side effect pretty well"
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5wlbee | why is our brain compressed? | What would happen if our skull allow our brain to be uncompressed? Not sure if this belongs here or /r/askscience | Biology | explainlikeimfive | {
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"I'm not really sure what you mean. Because our brains aren't really compressed. There isn't exactly high pressure inside our cranium. We do however have more folds in our brains compared to other species. That simply allows us to have more surface area and therefore more space to process information."
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5wlhyu | what is clean eating and what is a Keto diet? | Other | explainlikeimfive | {
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"Clean eating is eating natural, whole foods without additives and avoiding highly-processed products. Keto is a high fat, mid-high protein, low carb diet."
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5wljp1 | Why do people frown when they're thinking? | Biology | explainlikeimfive | {
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"Frowning seems to cause you to narrow your eyes so that you can reduce your field of vision. This cuts off extraneous information and lets you devote more brain time to what you are pondering upon. When I'm concentrating deeply, I tend to scowl, and people ask me why I do that and i say \"I'm thinking furiously\"."
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5wll4y | What happens when a company buys a competitor but keeps the name? | Internally, what changes for the company that has been bought? For instance, there is an insurance company named Esurance that was bought up by AllState Insurance a few years ago. Rather than acquire all of the customers and force them under the AllState name, they are still under Esurance and it doesn't seem like much else has changed except the fact that their commercials now say "An AllState company". Did the board get replaced by AllState? Did something else happen that was more drastic behind the scenes? I'm not sure what AllState had to gain by buying them up besides more money and one less true competitor, or is that all they wanted? | Economics | explainlikeimfive | {
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"Branding is important, and time will tell if those two brands have more value separately or together. A smart acquisition keeps its options open and gathers market intelligence over time to inform such decisions. Yes, they've eliminated a competitor. They've also expanded their business, now with two distinct customer bases: the traditional Allstate and the online eSurance. Each surely had lessons to learn from the other. Potential for a 1+1=3 situation. A business operation has a certain amount of overhead. Combining businesses has potential for economies of scale once they figure out how to merge their systems. (SO much easier said than done.). This is potential for 1+1=1.5 ... eliminating redundancies in overhead operations."
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5wllfv | We balanced the budget at the end of the 90's how hard would it be to do again? | Economics | explainlikeimfive | {
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"In the 90's a massive multi trillion dollar industry(the internet) was created out of thin air leading to skyrocketing tax income for the Federal Government that they did not predict, and did not budget for. If something like that ever happens again, the US will probably run budget surpluses for a few years like they did in the 90's."
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5wlqi5 | How is it possible for 2 quarks to cause the universe to collapse? | can you also give me a basic refresher of what a quark is? | Physics | explainlikeimfive | {
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"There are two types of matter particles, hadrons and leptons. Leptons (like the electron) are themselves fundamental...they can't be subdivided. Hadrons (like protons and neutrons) are not fundamental. They are made up of three quarks, bound together by the strong nuclear force. Quarks are fundamental. I have no idea how 2 quarks could cause the universe to collapse, though.",
"Quarks are attracted to each other not only by gravity and electromagnetism, but also by a much, much, much, much stronger force aptly called the “strong force”. The strong force has the curious property that, like a rubber band, when you pull two quarks apart they attract each other more strongly. This is quite different from gravity and electromagnetism, which get weaker the further apart you pull two massive or charged objects, respectively. Anyway, if you take quarks that are bound together by the strong force and pull them apart, it will take more and more energy to hold them apart the further apart they are. Eventually, it will take so much energy that it's “cheaper” from an energy standpoint for two new quarks to poof into existence and join to the original two. Then, rather than two quarks that are held apart, you have four quarks arranged in two pairs that are each bound tightly together. But if we pretend that that doesn't happen, what would it mean if we kept pulling quarks apart forever? Well, we'd need unlimited energy. At some point, the energy required would create a black hole. This is simply not a physically realizable state of affairs. In reality, quarks are only found bound to each other in balanced arrangements. But what if we suppose that we can magic two quarks into existence that aren't bound with anything else? Well, then maybe they'd be bound to each other. If they were very far away, then the energy required to hold them apart — which would be recovered when they zipped back together — would be enormous, and we might be talking about black holes again. But energy doesn't just come from nowhere — you'd have to expend this much energy to create such a configuration of quarks, so if you had a black hole at the end of the process you probably would have had a block hole in the first place. Now, if those two magic quarks were very far away, then it might be that it was “cheaper” energy-wise for each of them to steal a nearby quark or two to bind with. But then those quarks' former partners would be unbound, and the process would have to repeat until everything finally settled out. This process would release an enormous amount of energy. Really, this is still the same situation of arbitrarily large energy in, arbitrarily large energy out. Disclaimer: the science here is not fully understood, and those parts of it that are are not fully understood by me."
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5wlr4j | What is the difference between socialism and state capitalism? | Title. Socialism is, as I understand, where the government takes control of the means of production. If state capitalism where the state has control of production and the use of capital, how are the two any different? | Economics | explainlikeimfive | {
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"More accurately, socialism is an organization of labor and capital such that *the workers* exercise control over the means of production. The most common view of how to achieve this (favored by Marx) is for *the state* to appropriate the means from capitalists, and manage them on behalf of the proletariat. In Marx' ideal, such a \"workers' state\" would be temporary, leading eventually to a stateless/classless society. Anarchists, however, view states as entities that always inherently strive to preserve themselves, and so Marx was wrong on the feasibility of creating statelessness from a state. \"State capitalism\" is a derogatory term some use for the outcome of such societies, which have always replaced the existing privileged class with another who again benefit disproportionately from the labor of the proletariat. (In contrast, anarchists believe that the only way to reach statelessness, simply, is to *smash the state* and replace it outright with a non-hierarchial form of governance.)",
"Many here have defined socialism well, but IMO fail to expand on the state capitalism. Socialism is a political ideology, aimed at giving power to the workers. State capitalism is, in contrast, ideologically agnostic and is about the government controlling the means of production and/or the economy - without specifying the beneficiary. Yes, the USSR is one example in that it evolved into state capitalism instead of the stated goal of socialism. Some, however, have argued that the US government's decision to bail out the banks \"too big to fail\" is another example of state capitalism. Italy under the fascists is another example of state capitalism in an ideologically right-wing regime. For a middle of the road example one can highlight Norway as an example, due to its tendency for the government to be a key investor or 100% owner of leading corporations. And the same can be said of today's China."
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5wm27a | Why do we have lips? | This questions just randomly sprung up on me today. I was in class and I looked at someones lips and wondered why are they there. What's the point of our lips being all pink and looking the way they look? Why couldn't we just have all normal skin/flat skin cover our mouths the same way. I was in class just thinking like wow lips are weird like do we really need them do they really have a purpose or would we be fine with flat skin, but still have that skin cover our mouths | Biology | explainlikeimfive | {
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"I recently read the superb book \"touch\" which is solely about the sense of touch. The nerves in the lips are very, very sensitive. The lips serve humans as an excellent tool in sensory perception. This is most evident in infants who will constantly use their lips to explore items. Furthermore, the sensitivity of the lips makes them serve a key role as an erogenous zone. It is for this reason that kissing builds intimacy and affection. And kissing builds that intimacy and affection also in platonic connections, such as with our kids and parents and friends.",
"I don't have a super science answer here, but babies were mentioned above. Babies kind of flip their lips out and around the nipple when breastfeeding. We always think they're sucking on the nipple, but really the nipple is deeper in their mouth and their using their lips and jaw to get the milk out. And yes, I know that about 90% of that is potentially dirty. Chill out people, they're babies. I think there's a lot related to our mouths, too. Babies suck on pacifiers or thumbs to soothe themselves. They explore with their mouths. As adults we kiss to develop romantic social bonds. And we continue with some hand-mouth anxiety behaviors, like nail biting. Smoking and stress eating probably also falls into this category. Source- I work with babies and frequently talk about breastfeeding. And a healthy dose of pure speculation. TLDR: lips help babies breastfeed, they develop soothing behaviors around their mouths (ie thumb sucking), and use the sensitivity to explore their world. Then we continue some of this as adults.",
"URL_0 ^From the article: 1.) Nursing 2.) Speaking 3.) Kissing (a. pleasurable, b. adequate partner selection) Also, I remember watching this show about the science of attraction, and I think they said that lips remind us of sex organs; depending on the look of your lips, your potential partner may desire you more or less.",
"Mouths are essentially sphincters, and as such, the tissue at the end of this sphincter (the lips) must be able to fully seal. At the same time, us people have been known to open our maws up to chew on turkey legs and corn on the cob. We've evolved a yuge sphincter, one of the best sphincters, and we have the best people working on making them even better. MSsGA! Forgiving my one sentence joke, lips provide the dual function of opening wide and shutting tight. If you've ever squatted over a mirror, and I know you have, your anus has \"lips\" too. Our bodies don't simply wrap the same skin allover, instead, some skin performs different functions better. Further, let's look at the inside of your mouth. Your inner cheek flesh is kind of exposed, but a weak substitute compared to the leathery outside of your cheek. Lips are the transition between leather and meat. All hail the sphincter!"
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5wm7ul | if I am sitting under an umbrella and it starts to rain around me, is my body physiologically colder or does the surrounding rain simply make me feel colder than I actually am? | Biology | explainlikeimfive | {
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"Water has a high capacitance and takes alot of the surrounding heat out from the atmosphere. As the water fall from a high alltitude and is also already cooled bellow the surface temp. So you have cold water raining down being warmed by the atmosphere around you, thus it takes away the heat you so enjoyed before hand. My take on it!"
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5wmhp6 | Flinging rocks from the Moon to the Earth | URL_0 Brianna Wu's original tweet about this was helpfully screencapped by Dan O'Sullivan and, while it sounds absurd on its face, I honestly want to know whether there's any possible truth to this assertion. Can you fling rocks from the Moon to the earth as though they were weapons of mass destruction? | Physics | explainlikeimfive | {
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"No, no, and no. Escape velocity for the moon is 2.4km/s. This is many times faster than a rifle bullet. Any rock or rock-like object capable of making it through the Earth's atmosphere and still be able to cause significant damage would have to be massive. The meteor that exploded over Russia in in 2013 was about 20 meters across and weighed about 13,000 tons and it still exploded 97,000 feet above the ground. Small iron meteors could make it to the surface, but again, to do enough damage to make it worth the trouble, it would have to be massive or moving incredibly fast. The iron object that created the impact crater in Northern Arizona was around 50 meters across and impacted the Earth at around 20 Kilometers per second."
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5wmhra | Why is crab meat sometimes sweet when other meats aren't? | Biology | explainlikeimfive | {
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"The taste of Crab meat is significantly sweeter than other meats probably because of the higher presence of \"sweet\" amino acids such as Glycine and Alanine."
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5wmity | How was the first weight weighed without a scale? | Maybe this should be on r/showerthoughts too, but like... Scales need to be calibrated to ensure accurate measurement. And that object used for calibration has to be precisely weighed to ensure the correct calibration. How was that first object used for calibration weighed? Does this question make any sense? *How was the first scale calibrated without having a precise measurement for the object being used to calibrate it?* EDIT: So far it seems like the answers are alluding to that the *first* "measured" *weight* was just an object that was arbitrarily chosen by a group of people to equal "1 unit of weight"...Does that seem right? | Physics | explainlikeimfive | {
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"You use a [balance scale]( URL_1 ). A spring scale's measurement depends on how the weight of the measured item affects the components of the scale. A balance scale just lets you know if the two pans have equal weight on them, which is not dependent on the components of the scale and so it requires no calibration other than checking that empty pans balance. Remember that mass measurements are ultimately only comparison multipliers. There's [a particular ingot of platinum/iridium alloy in France which is defined as being 1 kg exactly]( URL_0 ). All other things are compared as being X times heavier or lighter than that particular object (yes, Imperial-users, yours too. The lb is defined using the IPK as reference).",
"At some point, you just pick an object which defines your unit of weight and calibrate against that. Locally, that could be a particular rock which your village agrees is how much a bag of grain should weigh. Then you ask the blacksmith to make lumps of metal which weigh the same as the rock, and use those to calibrate other scales. As you start to trade with towns further away, you find that their rock weighs a different amount and you find it more convenient to adopt their unit so that they'll buy your grain. In principle the kilogram is the weight of a litre of water. But the official definition comes down to a village rock. There's a lump of metal in Paris which weighs one kilogram by definition, and various copies around the world which are periodically checked against the original."
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5wmovc | WHY are the UK pushing for a ban on porn? Who would possibly benefit from this? | Other | explainlikeimfive | {
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"It will \"protect the children\". That's what the government claims it's about. Really I think it's just about trying to impose their Victorian morals on everyone. To be fair though, there's no talk of an outright porn ban. Not yet anyway. The plans are to apply the same rules to online porn as physical magazines and DVDs. So certain acts will be banned, such as urination (including female ejaculation because the government believes it's the same thing) and face sitting. It also means porn sites will be forces to implement age checks. There's a chance foreign sites which don't comply will be blocked. It's worrying times when the government is censoring the Internet like that, plus the fact that all our Internet history will be recorded and kept for a year. VPNs are probably going to become standard."
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5wmrwq | When does Homages or Parody become copyright theft? | Other | explainlikeimfive | {
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"This is a legal question, and it also varies from country to country (and IANAL). Generally speaking, though, the use of *any* copyright-protected material (which is nearly everything of artistic or literary merit -- copyright is automatic) without permission of the copyright owner is an infringement except in certain cases. US law is probably the most generous. It has a concept of \"fair use\", which is that certain uses of material is in fact perfectly legal. But rather than have a long list of these uses (as in, for example, German copyright law, which has a great long list that includes things like caching a temporary copy of a video on your hard drive so that the video player will actually work), it has a list of four broad criteria that a court uses on a case-by-case basis. This makes it very flexible, but means that you don't always know where you stand until somebody sues you. Those criteria are: 1. purpose and character of the use (are you using the source material to create something truly original?), 2. nature of the copyrighted work (how creative or artistic is the source?), 3. amount and substantiality (how much of the source are you using and are you using a particularly important part of it?), 4. effect upon work's value (are you making it harder for the copyright owner to make money?) There are no hard and fast rules; rather, the different criteria are weighed up one against the other and the court has to come to a decision. For example, if by \"homage\" you mean \"putting together some clips from a favourite TV series because you think it's awesome\", then it would very likely fail the test: 1. It's not original at all: all you're doing is putting together a few random clips just because you happen to like the show. 2. The copyrighted work is a piece of entertainment, so it's not exactly something that's in the public interest and not something that's really important. 3. You may not be using much of the total work, but you will have taken stuff that's distinctively and obviously from that show -- otherwise it wouldn't be a homage to it. 4. You're not affecting the market value of the original, so you're probably safe on that count. Parodies are often allowed because they are \"transformative\" (important for the first criterion) and parody is one of the reasons \"fair use\" exists in the first place, but a lot of people don't understand what a parody is. For example, taking that scene from the movie *Downfall* and adding your own subtitles to it isn't actually a parody: to be a parody it has to mock or criticize the original, but most *Downfall* \"parodies\" actually use the unchanged original to mock or criticize something else -- not a parody, but a form of satire. That will make it harder (but not necessarily impossible) to make the \"fair use\" case. As a rule of thumb, a parody mocks or criticizes the original it's copying from. Even so, you need to put some of your own work into it. And you need to be really careful: if you make a parody of *Downfall* with your own actors saying the lines but with *Yakety Sax* (Benny Hill's signature tune) playing behind it, you probably won't need to get permission to lift entire lines from the original movie, but you almost certainly will need to get permission to use the music (because you're not mocking the music, you're using it to mock something else). A court may well ask, \"But why couldn't you have used a similar royalty-free public domain track from the YouTube Audio Library, which would have worked just as well?\" Of course, none of this applies if the copyright owner gives you permission to do what you're doing. The idea is that it's that person's property, so if they want to let you borrow from it, you can, and you won't be breaking the law. TL;DR: In the US and some other countries, it's copyright infringement unless a court agrees that it isn't."
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5wmyvf | What is the true purpose of "Tag a friend who ..." spam-posts on facebook? | I guess it has something to do with facebook's algorithm for ads or something? Or is it just a ruse to gather personal information from people? They are annoying as hell and I'd like to understand why they exist at all. **Just to clarify:** I don't mean the Rolex spam hacks that have *you* involuntarily tag friends. I mean the posts from random very low-effort pages or just radio stations, often a "funny picture" where you are encouraged to tag a friend to embarrass them. | Technology | explainlikeimfive | {
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"Generating range, e.g., exposure. Getting a brands' name 'out there'. Every view, every click, every page loaded is, at its base level, an interaction with a brand, or product and a potential customer. Any page, be it a standalone website, a facebook page, a blog or whatever kind of means a company decides to use to promote a product, is 'counted' by said customer interactions. This is usually called the 'range' said medium can generate. An example from Twitter would be someone with 10 followers, writing a tweet. Let's assume that all 10 followers each have 10 followers of their own and all 10 retweet this one tweet. This means, with one tweet, the tweet is seen by (10x10) 100 possible customers. Now imagine a tweet written by someone who has 1000 followers, each with 100 followers. If only half of those followers retweet this single tweet, we're already at (500x100) 50.000 possible customers being exposed to the companys' product. Thus the range in the latter example is way higher, than in the former. This range is valuable in terms of what a marketing company, or similar, is willing (or has to) pay for their commercial to appear on said medium. That also is the reason why, in comparison, a print ad is much cheaper, than a tv ad - their range is hugely different. So, to come to a stop, all these 'tag a friend that...' sites try to enhance their own range, be it to gain a better position to sell their own products, *or* to have better 'arguments' when dealing with other marketing companies that want to place ads on their site."
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5wmzne | Why does inbreeding cause the offspring to have a significantly lower IQ than average? What is the science behind it? | Biology | explainlikeimfive | {
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"take it that a human body has 2 sets of genes. When a baby is made, half the genes are from the mother and other half is from the father. These genes make proteins which help our body work. However, there are occasionally some errors in the genes which ends up making defective/too much/too little proteins which give rise to diseases. Some of these diseases require 2 faulty set of genes in order to manifest. So if daddy has a defective gene but mommy contributes a normal set, the disease does not manifest clinically (or is milder). If there are many generations of inbreeding, the set of defective genes are kept within the same family tree; there is no new genetic input from a different family and thus the probability of having a child with 2 sets of defective genes increase. This increases the risk of diseases, out of which some may feature a lower IQ/brain malformations."
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5wmzvj | How does a Sinkhole happen? | Other | explainlikeimfive | {
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"Sinkholes tend to form in carbonate rocks, that is rocks with 50% or more CaCO3 making them up, limestone being a characteristic rock. Carbonate rocks erode easily in the presence of acids, and natural rainwater has a pH of approximately 5.6 (about what a cucumber is) due to presence of carbonic acid in the rain. This by itself is enough to erode limestone, but often decaying vegetation on the ground will make he water even more acidic. Water flows in streams, finds a weak point in the rock structure, a place where tectonic activity has fractured the rock, for example, and the water percolates into the stone. At the water-table and above it there is a lot of erosion due to the natural acidity of the water and caves grow. Eventually one of those caves grows large enough that the roof can no-longer support itself and collapses, creating a sink hole. The landscapes where this is common are called *karst* landscapes and occur globally where there is both exposed carbonate rock and at least 1 meter of rain annually (need that water for the erosion). There are other forms of sinkholes, but they are not as common and those also form in a similar fashion."
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5wn049 | Whenever I go out from a dark room and it's bright outside, my eyes'll start to water. Why is that so? | Physics | explainlikeimfive | {
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"Your pupil changes size depending on the light level. It gets big in the dark, and shrinks down in bright lights. The pupil isn't an actual organ though, it's just a hole. The actual organ is the iris, the colored part of your eye; it's actually a muscle. When you move suddenly into a bright light, the iris closes your pupil as fast as it can; and like any muscle, straining it can be painful. Tears are an automatic response to eye pain; intended to wash out any irritants."
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5wn34n | Why does milk make your sinuses more congested when you've got a cold? | Biology | explainlikeimfive | {
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"text": [
"It doesn't. Mobile now so can't find the source but there was a scientific study that proved it doesn't.",
"It doesn't. It's either something you've been told and you blindly believed it, or you've somehow made yourself believe that it does.",
"I don't have the source in front of me, but recalling from memory it is: It doesn't increase the volume of mucus. But a protein found in dairy bonds with (or possibly gets caught in) mucus and makes it feel more substantial. It goes from a fairly runny texture to a slightly thicker, sticky texture which makes you notice it more and makes it feel like there is more than there was before."
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5wn9s6 | Why is heroin and meth so addicting? | I find the subject of addiction so fascinating, like why would someone destroy their lives for a gram or two of these substances? | Biology | explainlikeimfive | {
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"> why would someone destroy their lives for a gram or two Despite the strong neurochemical aspect of hard drugs, I wouldn't say they make someone addicted. Keep in mind that people who turn to strong drugs are usually in a difficult situation psychologically along with a low socio-economic status, few opportunities in their life and usually some troubled relationships. Addiction is a way to feel normal/better than usual in an incredibly quick amount of time. Once they come off the high, the same old shit is going on and they have no reason not to turn back. I know I'll probably get downvoted by someone responding that 'not all poor people in shitty circumstances turn to drugs' and that's true but that doesn't mean that people will magically turn okay as opposed to not having taken heroin. If you think about it, heroin is the 'superhighway to a destructive cycle'. A lot of people think that if people didn't take drugs they would have been perfectly fine but most likely they would have manifested their problems in alcoholism, failing relationships, self harm, low self esteem, etc..all of which are much slower to detect and usually don't lead to death like heroin or meth do. In other words people don't get 'ruined' from heroin. They get ruined in slower ways which are much less noticeable.",
"Not to be a grammar nazi, but \"addicting\" isn't a word. The word you want is \"addictive.\" Coming from someone who used to spend $1200 a week on cocaine before I got away from it, I personally think it has to do with the fact that it makes one feel good. It changes one's perceptions of the world, and, in the case of cocaine, causes the brain to release endorphin and actually causes mood elevation. Cocaine is very destructive to the soft tissues of the body and, over time, wears one's nasal linings away, as well as the back of the soft palate. I was in a really bad way during that period of my life and it made me feel better. It helped me through the day, if you will. I know you asked about heroin and meth (I have never used heroin and I like sleep too much to have done meth regularly), but I feel that most people who \"destroy their lives for a gram or two\" would probably say the same thing I did at the time: \"It makes life less shitty.\"",
"I agree a lot with /u/femmejean . While chemical dependence can be hard to overcome it isn't the hardest part. One of the worst drugs when it comes to dependence is alcohol and that one is legal (quitting alcohol can kill you). The hardest thing about 'curing' addiction is to make it so that the addict doesn't crave the drug so much. The way to do that is to make him happy without the drug - fix his relationships, mental and physical health, living conditions, etc... The reason people crave that gram or two of substance is they feel bad. Maybe they tried it once out of curiosity but kept using because it felt nice. Then shit just keeps piling up and they just need to relax and have fun once in a while - what better way to relax than to have a bit of your favourite drug? As time goes on you find it hard to enjoy anything else but your drug and even that is loosing it's magic so you up the dose - you're already addicted for some time at that point. So, while to you it looks like they are destroying their lives to them it feels like they are holding on to the last straw of positivity. Now, whats special about meth and heroin? They are easy to get into (no heavy halucinations or side effects) and seem actually harmless when you try them. Most people describe it as just feeling nice (heroin) or energized (meth). Only when they are already addicted and are upping dosages you start seeing all the side effects.",
"I study this and work with detoxing addicts for a living. If you want the ELI5 answer and not the r/askscience answer here it is! Any combination of: Genetic predisposition (does your family have a history of addiction? Will your body biologically have a stronger reaction to drugs because of this?) Social environment (is the person experiencing a lot of stress that could draw them to drugs? Do their friends/family use?) Psychological factors (are you prone to being more impulsive and thrill seeking? Will you rationalize your reasons for using?) Fittingly called the biopsychosocial model. There ya go (:",
"The substances that are most addictive are going to be the ones that create the most \"pleasing\" effects (the bait) and which can cause both psychological and physiological dependence (the trap). For many people this typically would be opiates / opioids like heroin, vicodin, Dilaudid, oxycodone, methadone etc usually used to temporarily negate physiological and/or psychological pain, alcohol for the same reasons as well as possibly as a \"sleep aid\", and stimulants like cocaine or methamphetamine as they increase stimulation (countering boredom) and create pleasing sensations by activating the limbic system and especially dopamine (the pleasure neurotransmitter) among others (seratonin, norepinephrine) which can counteract depressive feelings temporarily. PS someone smarter than me correct me if I am wrong, my neurobiology is a bit rusty.",
"[Long as Balls] In really basic terms your brain has neurotransmitters that are released from neuron to other neurons to transmit that something happened (i case of the drugs something apparently good) and drugs act with those neurotransmitters by many ways, either releasing a bunch at the same time, or making the substance that stops them from acting after a certain time not work properly, and your brain's reward center likes these neurotransmitters working because they were made to reward you of something good you did (the feeling of eating when hungry for example), and when there is a lot of them released your brain thinks you have made something really good (not really though) and wants to reward you by making you feel good and wanting to make you do it again, and again, and again…",
"Bruce Alexander, a psychologist, conducted a study in the late 1970s where he challenged that the addictive hooks in the chemicals of heroine were what made people addicted. He looked at the experiment where they placed two water bottles in the cage and nothing else. He basically came to the conclusion that the rats had nothing to do. So he built rat park. It was basically a rat community that had everything a rat would need to be happy and content including members of the opposite sex. He had two water bottles in it. One clean and one laced with heroine. The rats almost exclusively drank from the clean bottle and rarely from the other one. He determined that it was society and not chemical addiction that played a bigger part in the behaviors of an addict. I am not discounting the chemical hooks in drugs, yet it has been clearly and scientifically argued that societal settings determine whether someone is recreational or an addict."
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5wnavs | Why do you get tax breaks when married? | Economics | explainlikeimfive | {
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"You don't necessarily. You get tax breaks for owning a home and having kids, but my ex wife and I lived in an apartment. When we filed jointly we got much less than we would have had we been single.",
"There aren't tax breaks for being married, per se. There are higher tax brackets for married couples filing jointly based on total income. But this is only really a difference when it's a single income household or one makes greatly more than the other partner, as it effectively spreads one income over two people. But if each partner makes roughly the same amount, there isn't any benefit to being married w/ regard to taxes. For example, let's say a dating couple have incomes of $20k and $100k. When married, they'd pay slightly lower taxes on a joint $120k income than separately. But if they made $58k and $62k it wouldn't much matter."
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5wnf8c | How do military invasions actually happen (both land based and naval?) | I was just wondering how armies actually invade other countries/areas, surely when the military forces arrive there wouldn't really be anybody there - let alone an opposing army - especially in areas like forests/other rural locations. When does the fighting occur? Similarly how do naval invasions work? How can ships in the sea influence the warfare on land and help military forces to capture cities/regions? I'd appreciate if anybody could explain how this happens with examples? | Other | explainlikeimfive | {
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"Army officer here. One of the things we learn about in tactics is called movement corridors. Basically, to move a unit of a certain type and size effectively, you need a certain amount of space. Most places in the world have terrain features or man-man obstacles that restrict the size of these corridors, so it limits where an invading army can come through. There are only so many corridors where you can move hundred of vehicles and thousands of Soldiers. This, plus good surveillance / reconnaissance assets, allows a defender to predict where an invader will attack, and to pick advantageous defensive positions to prevent he invader from doing so effectively. But that said, you're right: lots of a country isn't really of particular strategic value or tactical advantage. So, a defender might let the invader move unopposed through these parts until they reach somewhere where 1) a defender has an advantage, like high ground, a river crossing, a narrow pass through the mountains, etc., or 2) where the defender has some reason to mount a defense, like a major city, important bridges or roads, etc. A wise attacker will also be thinking about these things and looking for ways to force the enemy to fight on disadvantageous terms. A huge amount of strategy is trying to guess where the enemy will go and what he will do, which requires you to understand his motivations. Once you know what things he was has to defend (we call these centers of gravity), you can determine how to exploit them. That could be by forcing him to fight where he is outnumbered or on bad terrain, or by bypassing likely points of defense to get around the enemy and strike other objectives like his supply lines, cities, etc. The other (and more important, really) thing to keep in mind is what both sides are trying to accomplish. War is politics by another means, as Clausewitz says. An invader with limited goals is going to fight different than one who wants to absorb the defender's territory. If all you want to stop local raiding across the border, you seize the border towns and the key terrain around them, and you stop. If you want to change the regime, you fight to the capital and try to snatch high value people. It's a little simpler for the defender: keep the enemy from imposing his will on you, stop the fighting, and exact a hard enough price to keep them from trying again. Of course, huge simplifications here, and that doesn't touch on the what all of that strategy looks like in practice. But hopefully that answers at least part of the question."
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5wnkfu | What happens to an unborn baby that is going to have a nut allergy (or any other type of allergy) when the mother consumes nuts? | Or are allergies only formed after birth? Is there any kind of genetic disposition to them, or anything like that? Does it hurt the child or is there no way for an unborn fetus to have allergies? Thanks! | Biology | explainlikeimfive | {
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"It doesn't hurt the child because the mother is processing the food for the child. You mostly want to avoid things that get into the blood or can be passed through the placenta to the baby and have a harmful impact (such as alcohol). Studies have actually shown that mothers who eat nuts during pregnancy have children who are less likely to be allergic to nuts.",
"Allergies are environmental. An unborn baby does not have any allergies. This answer is probably going to get removed for being too short, but current studies are starting to suggest that nut allergies are caused by parents preventing exposure to nuts at an early age for fear of nut allergy. The 'allergy' is then an overreaction of the immune system to nuts due to it being so foreign to the body.",
"Oddly enough, it seems that you **want** to expose children to, say peanut butter (and other allergens). This decreases the odds of developing allergies. We don't understand allergies too well, but it seems then they develop during the life of a person, they are not something you are born with. Or maybe that early expose helps the body learn to deal with the thing they would have had reactions to. ~~ URL_0 URL_1 EDIT, linked wrong page.",
"The metabolism of a fetus is separated from the metabolism of the mother by the placenta, and only a relatively small amount of substances can pass through it - specifically nutrients, but also some drugs (both medical and recreational). Allergens generally can't. Additionally, the fetal immune system is [different from the adult one]( URL_0 ) and generally very tolerant. It doesn't have to fight infections since the mother will do that. However, we don't actually understand very well what causes allergies. So it's pretty much impossible to say how a mother's diet could increase (or decrease) the risk of the child to develop allergies."
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5wnsg8 | Is there a way to describe multiplication of two negative terms vividly/picturesquely/descriptively? | For example if I have two apples and add another two apples i end up with four apples. If I have two apples and double them, i have 2x2=4 apples or 2+2=4 apples. If i have -2 apples (need for two apples) and want to double them i'm in need for four apples. Clear. But when i need two apples and duplicate them with -2 i end up having 4 apples. | Mathematics | explainlikeimfive | {
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"Multiplying by negative one (-1) is like making something opposite, that is turning it around. So taking something like $100 of debt and multiplying it by -1 turns it around to a $100 credit. Multiplying by -2, turns it around AND doubles it... So if you owe me two apples (so you have -2 apples) and I multiply it by -2, it turns it around so that I now owe you AND it doubles it... Now I owe you 4 apples... you have +4 apples... (-2)(-2) = +4 tl;dr Multiplying by a negative makes things opposite"
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5wnth1 | Why are crutches in the US supported from the armpit area but ones from the UK supported by the hand? | Like surely the US ones could do a little damage and cant be good of the blood flow | Other | explainlikeimfive | {
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"The tall crutches that go to the armpit are generally used for short term injuries. They are easier to use and require less balance and arm strength then the forearm only ones but make you move in more of a swinging fashion. For long term use the forearm crutches are popular in America. Also you aren't supposed to have the tall crutch in the armpit, they go in the meat of the arm before the armpit, the top of your bicep tricep area.",
"Crutches in the US have pommels to grab beneath the armit supports. You are not meant to put all of your weight of your arms onto the top pads, but rather, use them as supplementary assistance."
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5wnx0q | When a bug gets stuck in your car and travels a few miles with you before it gets back outside, does it ever find its previous home/nest/colony again? Does it care? | Other | explainlikeimfive | {
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"That depends on the bug. Some bees have been shown to be able to re-locate their hive after being separated by a reasonable distance. Over time they learn the area while foraging and can find their way back if they're not moved too far. Ants trace their location carefully with scent and would be lost if moved. Most non-social insects don't really have a permanent \"home\" and would just do bug stuff in their new location.",
"In a forensics class I took, we were learning about the body farms that can be found throughout the USA. An experiment was done involving decomposing rates where flies were taken off a body, placed a drop of paint on their back for marking, and driven a few mile(s) away. The flies were recorded to have made it back to the body before the individual who drove them away did. Edit: Redditors, please donate your organs and body when you're through with them. Advancing the sciences and medicine requires bodies. Medical schools would love to use you as a cadaver. And afterwards, if you're lucky, your body might be the next \"Mr Bones\" in Mrs. Smith's 6th grade science class",
"I learned from my Turf-Inscets professor that ants relocate to their ant piles by using familiar smells, sun and the gravitational pull. Ants are a truly magnificent creature... Not related to location, but a queen bee can release a pheromone that causes the rest of the bees to bite the hive, tear it open a little and flutter their wings making a draft for the queen bee to cool off.",
"Damn these are some really good explanations! thank you folks, this has always crossed my mind lol"
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5wo30o | Why wouldn't an economist be the ideal candidate to lead the country? | /why aren't more of them in office or running for office? | Economics | explainlikeimfive | {
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"Well in terms of governing, the economy is integral, but its not the only thing that matters. In addition, because the president has economists as advisors, he wouldn't himself need to be president. A president also has to be able to sway voters, which can be much more to do with feelings than facts.",
"Same reason a general generally would not necessarily be, even if he is the commander in chief. Economy is an important aspect, but still only an aspect. What a president needs to be before any other trait is a leader. He has generals and economists and a ton of other advisers on any and all topics, so he doesnt need to be an expert in any of them. He needs to lead the team under him, inspire trust and safety to the public and make the best decision possible for the best of the country when required. These are the most important trait. Its not that an economist would always be a bad president, but its not related since he has a team of economist to do the research for him and advise him of their finds so being an economist himself would have little benefit to the president. Actually being an economist or a general (or a business owner wink wink) could actually hinder a president because they come with their own expertise and therefore their own biases. Its harder to follow someone else's advice when you already have an idea on the matter due to previous work. But who would you rather make the advice? A team of experts working solely on this particular issue or a single expert not devoting 100% of his time to the topic?",
"US perspective here. A good president can inspire confidence in Americans. They are popular and well-liked. They then, in turn, hire advisors and staffers to help guide their decisions. Most pubic opinion polling shows that in 2004, more people liked John Kerry's policies, but they liked George Bush as a guy and as a leader. Same thing in 2012 with Romney. Obama won because of the proverbial \"who would you rather have a beer with?\" factor. People want personalities in their leaders, they don't necessarily want nerds.",
"People hate and I mean HATE economists and the answers they give. Let me remind you - the vast majority of economists believe outsourcing is a good thing. A lot of economics is counter intuitive and beyond the simplistic answers that the public likes to hear. [Here is an episode of NPR answering EXACTLY your question]( URL_0 ). You really should watch it, it's extremely interesting. They got five prominent economists together and created a platform that nearly all economists could agree on and would love, and tried to market it to the public."
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5wo3cq | Why is there a strong drive to prove others wrong? | Some people on the internet (hello reddit!) will go out of their way to prove to a stranger they will never meet that a certain point is wrong. What is the psychological reason behind this? | Biology | explainlikeimfive | {
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"1.) Helping somebody else, even if that person is a stranger. The fact that it's on the Internet doesn't particularly matter. 2.) Helping lurkers and searchers. In this case, the Internet increases your reach exponentially. 3.) Making sure your own position is correct, which helps you. The Internet allows not only the OP but anyone else to chime in. Which theoretically can generate the best counter-arguments to your position.",
"As I've gotten older I've realized that people who do this a lot are usually train wrecks. Other things in their lives are a mess so they compensate by getting a win over something often mundane. For younger people I think it's just a natural self validation that you can learn/teach and influence. Once I hit my 50s I realized most of the time I could care less if you're right or wrong. But I also think what you are perceiving is just magnified because you're on reddit!"
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5wo4sr | Am I a day older or a day younger now? | A few years ago I traveled around the world starting with me flying west from London to Los Angeles in one day. A week later I flew west from Los Angeles to Melbourne (via Auckland), jumping the time/date line. I took off from Los Angeles on Monday night at 10.30pm, landed in Melbourne at around 7.30am on Wednesday morning, completely skipping Tuesday. I eventually flew back to the UK in a westerly direction via Tokyo so I never jumped back east over the time/date line to correct the original loss of a day. It's never really been an issue until I was explaining to my 6 year old daughter about time zones and the time date line, and I realised that I once missed a day of the year out. So, do I need to adjust my birthday forward or backwards a day to compensate? | Other | explainlikeimfive | {
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"Neither. > A person who goes around the world from east to west (the same direction as Magellan's voyage) would gain or set their clock back one hour for every 15° of longitude crossed, and would gain 24 hours for one circuit of the globe from east to west if they did not compensate by setting their clock forward one day when they crossed the IDL. So basically, because you went all the way around the world in a western way, then as you went you kept setting your clock back one hour due to changing time zones. The day you set *forward* is to compensate for that, so you don't end up mysteriously going back in time one day (because that's not what happens). If you just traveled *extremely* fast around the world, you wouldn't set your day forward over and over again as you pass the IDL, because at some point during your journey the day would go *back* to the day it was when you first crossed the IDL due to the time zones in between.",
"In all seriousness, time can only progress forward. You can only grow older, not younger, so therefore, you'd be just as old as if you'd stayed home. Time zones are finicky things, but the one rule of time is that it can only progress, not regress. You were still born on the same day of the same year at the same time, and that cannot change. You didn't really lose a day, it's only a perceived loss."
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5wo6gj | What are penny stocks as mentioned in The Wolf of Wall Street? | Economics | explainlikeimfive | {
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"The simplification is that penny stocks are stocks worth less than a certain amount. Every country defines them differently, but in the US the SEC considers any stock trading under 5$ as penny stocks. Many of these are from smaller companies and the reason people invest in them is because it has possibilities of higher rewards quicker since any movement has a lot more effect than on blue chip stocks (established companies like banks). A stock worth 0.60$ gaining 0.05 is a lot more important than a stock worth 60$ gaining 0.05. Plus many penny stocks are newer companies so there is more upside since any good news (finding a gold mine, developing a new software) can create faith and make the price rise drastically. The risk is that the company doesnt find that gold mine or interesting software and the price falls even more. Just like rises, drops have a significant effect. Its a high-risk high-reward game. Since you mentioned the Wolf of Wall Street, Ill go on a side-note: OTC (over the counter) or pink sheets. OTC is another stock market in the US (just like Nasdaq or NYSE), that is less transparent and regulated, even more so during the years in TWoWS. Usually, companies that register on the OTC are either too small to enter the bigger exchanges or are unable to pass the required audits (more shady). There have been examples over the years of incredibly shady companies (2 guys in a shack wanting to start a pharma manufacturing company type of thing). Unscrupulous brokers would sell those to people as a the next big thing and people would buy that. And pink slips had very high commissions to encourage brokers to sell them, regardless of whether or not they fit with the client. Plus if a company was registered on NYSE, people could confirm a lot of information like number of employees, budget, etc. But OTC having so little audit requirements made it easy to sell a shack as a corporate headquarter and 2 guys as a team of experienced scientists. These are the pink sheets DiCaprio sells when he moves to the shady broker after losing his job and then out of a garage. [OTC]( URL_0 ) still exists today and is more regulated, although still nearly nowhere as much as the main exchanges (in NA thats NYSE, NASDAQ and TSX) and are not as transparent (even with Bloomberg paying programs we cannot see the bid and ask for stocks, something Google Finance has for free for the main exchanges and you cannot see other important information like market depth. While were at it we can talk about the pump and dump that they also do in the movie. Pump and dump is buying a bunch of stocks of a company that doesnt trade much and then convincing a bunch of unsuspecting people to buy a lot of shares as well. Because the volume isnt high, if many people are buying that share, it will drive the price up (market price is based on supply and demand. If demand goes up and supply is unchanged, the price rises, sometimes drastically). Once you sold it to enough people that the price is well above value, you sell all your share on the market taking advantage of the high prices. Since suddenly supply rises quickly and not demand, the price will fall. The person organizing the scheme makes a lot of money, but all the small investors that bought in while it was climbing (so over its actual value) are now left with a share that is worth less then what they paid and so are losing money. It works with all share (they do it with the Madden IPO in the movie, keeping shares for themselves and then selling hard), but it works better or faster with penny stocks that just \"found a cure for cancer\" or \"the biggest oil reserve in the pacific, BUY NOW!\". Hope this helps! Finally an ELI5 in my field that doesnt have 1000 answers! Feels good!",
"When a company goes public it have to split the company into equally sized shares. So they have to decide how big each share should be. If you have too few shares and the company grows to become very big then each share might be more then most investors are willing to invest in the company. So a lot of small companies will rather make many small shares instead so they do not have the same problems as they grow. So you are talking pennies on the shares instead of hundreds of dollars that is more common in big companies. These small companies are also not able to be listed on the big stock markets and have to settle with smaller stock markets that specialize in these kinds of stocks. These markets are more popular with venture capitalists as they might hit the jackpot with a trade but if a company goes bankrupt they have not lost much. There also tends to be less oversight in these smaller markets so you can find a lot of predatory marketing techniques and straight out scams as there is less chance of getting caught."
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5wo7vi | Why can humans only hold their breath for a few minutes while, say, marine iguanas, with their tiny lungs, can hold it for about 30 minutes? | Biology | explainlikeimfive | {
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"Pound for pound, mammals require about 20x more energy than reptiles. That means mammals will require about 20x the food and oxygen to survive. 30 / 20 = 1.5 minutes, so the math checks out.",
"\"Humans are what are called tidal breathers. When we breathe in, fresh air moves into our lungs along progressively smaller airways, eventually ending in little sacs called alveoli, where our bloodstream picks up oxygen and deposits carbon dioxide. Then the \"old\" air moves out of our lungs along the same path it came in. But birds, alligators and monitor lizards are \"unidirectional\" breathers. After the air moves into their lungs, it begins to follow a system of tubes similar to arteries, capillaries and veins. In this system, the air moves through the air tubes in only one direction.\" Edit: [Source]( URL_0 )",
"Sounds like iguanas have been covered already. In case anybody is wondering how mammals can hold their breath longer, they have a lot of a different form of hemoglobin called myoglobin which is usually found in our muscles. It's much better at holding oxygen than hemoglobin and allows them to more readily \"store\" the air. Simplified obviously but that's the basic picture.",
"There are many things that go into this phenomenon including things that [kouhoutek] mentioned where reptiles such as the iguana use much less oxygen (as they are cold blooded). However, just to create one complied answer I am listing some of the big factors below: **1. CO2 in Lungs** - When we hold our breath and have the feeling to exhale, that is caused by an accumulation of CO2 not a depleted amount of O2. If you go into a room with just 2% extra CO2 in the atmosphere, you will feel as if you are suffocating even though there is enough oxygen to survive. Animals like iguanas (and even mammals like whales) don't respond to a small change in CO2 in their lungs. They are able to hold a lot of CO2 in their lungs without having a need to breathe. **2. Slow Heart Rate** - All these animals who have the ability to hold their breath for this long have adapted over millions of years to do so just as [WRSaunders] mentioned. One of these adaptations is to be able to keep a slower heart rate when their breath is being held. This allows them to have a slower metabolism when their breath is being held in turn causing them to expend less oxygen when their breath is being held. However, this slower heart rate doesn't happen when we humans hold our breath, in fact the heart rate increases. **3. Positively Charged Myoglobin** - Myoglobin, similar to hemoglobin, is a protein found in the muscles that is able to have oxygen bind to it. Animals who can hold their breath for a long time have many positively charged myoglobin proteins which allow them to have a large reserve of oxygen in their muscles. Normally when proteins get too close to each other they clump up and cause diseases/disorders such as Alzheimer's but in these animals, the myoglobin proteins are all positively charged and repel each other. This allows them to be packed in tightly without clumping up together which enables them to hold a LOT of oxygen in their muscles (and blood in hemoglobin). In fact, 45% of muscle mass in some whales is due to a large amount of myoglobin. **4. Cold Blooded Uses Less Energy** - Warm blooded mammals spend a LOT of energy trying to keep their blood warm, however, cold blooded reptiles such as iguanas don't spend a lot of energy (and oxygen) to keep themselves warm. This allows them to use oxygen more slowly which means they can hold their breath for a long time despite not holding much in their lungs. I highlighted the main points above, however you are free to explore more on your own. [This]( URL_0 ) site might be able to help. *If you have any more questions don't hesitate to reply below and I will answer your question(s) to the best of my ability. If you thought my answer was helpful, please just take a few seconds to leave an upvote. Thanks! :)*",
"For the same reason iguanas can't build airplanes even though they have 5-fingered hands. Species adapt to their niche, and in our niche the huge brain with all its large oxygen demand is a competitive advantage over staying under water for 30 minutes."
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5wo9y2 | Why can't you compress a RAR file with RAR or ZIP? | Why can't you compress a RAR file, | Technology | explainlikeimfive | {
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"Compression is a technique for finding patterns in a file and writing it in a way that takes more space. For example instead of writing \"aaaaaaaa\" you may write 8*\"a\" which is much shorter. Or instead of writing \"abcdefgh\" you may write \"a\"-\"h\". However if you have already compressed a file and written it in the shortest way you can think of then another compression program will not have much luck trying to compress it further. If you think of your file as a sponge. It consists of a sponge material and a lot of air. This is practical for cleaning but not very practical for transport. So you put in though a vacuum sealing machine to suck all the air out and put on a plastic seal to keep all the air out. Now the sponge is much smaller. But you read of another way to do it by using a vice. However when you put the already compressed sponge in the vice you can not get it much smaller. This is like trying to compress an already compressed file."
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5woe50 | Why can't we just cover a proportion of the desert with solar panels to provide the world with energy? | Technology | explainlikeimfive | {
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"So electricity. It needs to be moved and can only be used as generated without significant infrastructure. So lets just look at moving Electricity from Arizona to say Maine. Line losses. Electricity needs to be at high voltages to move it. that is why AC won out over DC. Not because Tesla rocked and Edison was a jackwad, but because DC has a limited transmission range. Literally in the couple miles range. So we need AC. Solar generally makes DC. So the DC needs to be put into a converter that makes the DC into AC. Because we live in reality and not theory or make-believe there will be losses in converting the DC to AC. Also a line 100 miles (160 kilometres) at 765 kV carrying 1000 MW of power can have losses of 1.1% to 0.5%. A 345 kV line carrying the same load across the same distance has losses of 4.2%. So if we ran 765KV line from Arizona to Maine is like 2800 miles long. That is a considerable amount of losses. That comes out to about a 25% or better loss in the transmission of that power. So to combine the losses in the generation and swap to AC and the line losses you end up losing a huge amount. Additionally at the beginning and the end you have to step up and then step down the voltages. That incurs more losses. So overall the losses from the Sun hitting the PV panels to someone turning on their TV in maine incurs a huge efficiency penalty. So while the solar source is free, the transmission equipment, transformers, and all the other equipment is not. So now if you take the standard that solar runs at: about 10-25% and apply that and the losses you get huge generation numbers for what would need installed. 11 million MW hours of power were consumed. So to math this 11,000,000 MWh of power needed. So we need to up the production to account for the losses. So let's divide that up into 365 days of use and 24 hours per day. That comes out to needing an average of 1255 MW of production. Now we add the losses we have to make up for. That comes out to 1794 MW of production. Then we have to throw in the Capacity factor of solar. The industry runs low compared to other power systems. But a plant in Arizona has been hitting 29% so we can use that. that means we need to start with 6185 MW of faceplate capacity. And we need to be able to store that power. We haven't added storage in yet. Since the solar must be stored some place for when the sun is down. That will add in more losses and therefore more base capacity to meet the needs of the end user. Agua Caliente is 84 MW of faceplate capacity on 2400 acres. So we need to multiple and we come up with 176,735 acres give or take. That is about 276 sq. miles of solar. The problem is not with the production of solar electricity. The problem is with storing and moving the solar electricity. The other thing we have not talked about is maintaining grid stability. Thousands of small PV site feeding into a huge grid with nothing to anchor the grid will make it unstable. When a large industrial plant starts a bug line up or a aluminum recycler starts the induction heating process that load has to be absorbed and these small PV suppliers cant handle it. There are vast engineering problems that need to be solved here. NO it is not impossible, but it needs to be looked at as a whole, not just little pieces. Too many people assume the only thing that needs power is homes and basic lighting and ignore the rest of the grid and the businesses and industry we have in this country. We need a grid they can rely on. The problems are solvable, but not by activists pushing their favorite flavor of solution or the neat product of the day. Power walls are great. Except for all the drawbacks they have that we ignore. Solar is great except for some of the drawbacks. nuclear is great except for some of the drawbacks. Ask your self why we are shutting down already operational and carbon free nuclear plants, but are willing to pay extra in taxes to build carbon free NEW renewables. It is stupid. And it ignores the facts of the grid and engineering. Solar cannot be used as abase load. And the technology for storage is more in its infancy than renewables are. And before we can really have any chance of renewables really supplying the whole of the grid, storage has to be solved.",
"Who would be doing it? If you're doing it for the public good that's a government project and you need to convince stubborn politicians that it's a good idea. Good luck with that! If you're expecting to make money you need to deal with ongoing maintenance costs as well as the initial setup (even if initial setup is relatively cheap these days). And then you need to make they money back by selling the power, but what if the price of power goes down because you're providing it in such large amounts? There are some practical concerns though. Moving electricity is not free or completely efficient. Distributing power around an entire country ends up wasting a lot of it and requiring strong infrastructure and these problems would be even worse with one central source a far distance from where the power is used. And what about nighttime? Storing electricity is a problem that has NOT been solved on the type of large scale such as \"powering a whole country\". And solar panels on opposite sides of the world somehow covering for each other when one side is in the dark increases the problem of distribution even further.",
"Solar engineer here. Let me explain some of this that's been covered by some people already. __Why Not Solar In Deserts?__ If we are talking a new array away from people, someone has to lay out all of the infrastructure for it to deliver power to the grid. At the same time, someone also needs to figure out how to shut it down when the largest source of power on that power grid fails because pumping electricity into a powered down grid can have disastrous results. This is typically solved in home solar with a fast disconnect, in which if power to the home stops the array ceases function to help the main power company in the area get things going again. Next is maintenance on the panels. The thing about large constructions in remote areas or even out of the way spaces is that most companies that put something out there intend not to have to come back to it unless they absolutely have to. The issue with this and solar is panels may die, panels need cleaning, sun tracking mountings are expensive as fuck, and you'd have to pay for all the equipment and people to facilitate taking care of all this. The same fast disconnect isn't a great solution at this kind of scale either. Large power systems like this require a lot of extra engineering and planning and sometimes implementing solutions that don't even exist or cannot just be found off the shelf. (Gonna also drop that you'd have to landscape the desert unless you find a really nice flat spot and even then, you may want to have a leveler come through anyways.) Ultimately, there is a lot that needs to be managed that just aren't realistic to manage. At the same time, anyone who puts an array out somewhere needs a way to make money off it. They probably aren't going to be able to get the power company to pay for large sums of solar power without it being discounted a lot. After all, if I was a power company I don't need to buy power from someone else. The city may not because they are already getting power from the already existing grid owner. Leaving you only able to sell to new developments and offer power along side the power company to homeowners, at which point, why aren't you just an extension of the power company? And the power company does not have an industry interest in solar because fossil fuel is a bigger money industry. (This statement is wrong, check out /u/Halfway_Bayesian [post]( URL_0 ).) At the same time, your power needs to be as always available as a regular power company for emergencies and panels do not produce much at night. __Future of Solar then?__ I honestly think that the future of solar right now is in residential. Most homes can hold enough panels on their roof to offset all of their electrical costs and for a pretty fair price (about the cost of a car, between $10,000 to $40,000. Consider pricing is on average, $3.50 per watt on a panel.) I've seen in just the last two or three years alone panels going from 225w panels to 290w along side batteries and even solar shingles. The technology is improving fast and we will see a lot more of it in the next few years. However keep in mind too, not every place in the world is geographically suitable for solar power. Locations too far North and too far South won't get great benefits from solar power. Neither would a place that you could essentially call a forest. Solar I don't believe sells well in Canada or states and countries along the same latitude as Washington or Oregon state. [Check out Huppie's post here.]( URL_1 ) where they discuss solar at these more northern latitudes, I learned something new. To put things in perspective, if you live in Utah with a good South facing roof, 8 modules of 290w are enough to offset 3,000-4,000 kWh of usage at your home. For a lot of small homes, this can be all you use for a year. A lot of solar companies offer their own maintenance services or even equipping an array with other necessities like \"critter cages\" to keep birds and squirrels out from under your panels. Otherwise, you may have a ton of fried birds under your panels. They get hot. __Problems that Face Solar__ The biggest issue with the solar industry for individuals is electrical companies because they are virtually untouchable. The reason is that they technically own the power grid and if the entire city depends on it, there is nothing that can really be done. A lot of power companies lobby to keep solar out as well. If you do some research, Nevada was a booming industry. Then Warren Buffet's Pacificorp, changed how solar customers pay their bill for having solar. Essentially, they put up a premium that brings your power bill to, still less than before, but not as much savings. On top of that, you're now also buying power from a solar company or paying for panels under a loan or lease. Pacificorp, claims that they lose millions of dollars per year on administrative fees and are recouping that cost from solar customers with this premium. Some electrical companies won't even allow residents they service to have a solar panel system. There needs to be more policies for solar friendly developments and incentives for the industry. There are some, but there are also powers in the world that are cornering the market on power and do not want solar coming around because so far, solar companies are already undercutting profits from the grid owning electric company. I think there needs to be a lot more cooperation between power companies and solar companies rather than the electrical companies governing and restricting how power is being provided to consumers in an area. Tldr: __Solar panels require a lot of maintenance, the idea itself has a lot of business and municipal policy issues, and these same issues extend to the entire solar industry. Its much more feasible for residential solar to be happening for society as these same problems tend to be cheaper when costs can be levied on a private customer.__ If you want to be the one to do that though, do it.",
"Storage and transportation. You can keep a barrel of oil for months and it will still be good. You can cart a barrel of oil halfway across the world and it will still be good. And we do this. A lot. A barrel also doesn't cost much to make and can be made out of cheap materials. Getting solar power from the Sahara to Stuttgart is going to be difficult. Once it's electricity it has to be used immediately. Batteries are really expensive and made out of things that are bad for the environment. Other cheaper things like boiling salt lose energy very quickly. Building power lines that far will cause a lot of power to be lost on the way. Some scientist are working of a way to turn the energy into oil and burn it later, but it's still in the experimental phase.",
"Short answer is, we could, but it's not entirely efficient, and it would require a big chunk of money, and we'd have to deploy *vastly* more than we'd want/need to make up for that inefficiency. Other people are saying electricity can't be stored. This is obviously false. Even taking aside batteries, electricity is just energy, and you can store energy countless ways: pump water uphill, then harvest hydropower later. Lift a heavy weight, harvest the energy later to produce power, etc, etc. There are even solar plants that are [specifically designed for nighttime power generation]( URL_0 ). The other end of it is forcing transition. Oil/gas is still cheap, and there is a *huge* amount of infrastructure in place for deploying it. It's going to take a long spin up before we can compete with that.",
"Only one other person mentioned it, but why would we do that? Most of the world's deserts have incredibly fragile and ancient ecosystems. It is pretty interesting but read about the microorganisms that live in the sand at White Sands National Monument. I believe you are not allowed to stray from the path because of how fragile the organisms in the sand are. They have created these layers on top of the sand over long periods of time. That would be a great place to put millions of solar panels but at what cost? Albeit mankind is not known for giving two shits about what we destroy. Also, it would be a logistical nightmare.",
"Largely because the sun goes down at night. We have few effective ways of storing large amounts of the energy we produce. That means at any given moment, we have to produce about as much energy as we consume. Our current power grid is divided into two main kinds of generation. *Base load* is cheap and efficient power that is slow to start up, like coal fired steam turbines. This provide most of our power, but is slow to adapt to changing demand. *Peaking load* is provided by more expensive but quick to start up sources, like diesel generators. They can be started and stopped rapidly as demand requires. Unfortunately, solar and wind power are not real good at either, because you can't presume they will be available. At best they provide a buffer between base load and peaking load, but both of those other energy sources need to be available.",
"-First you have to convince politicians to get on board. -Then they have to convince the public to get funding. It would be expensive. So convincing everyone will be difficult. Do we raise taxes? -The cost maintenance is expensive. -There is also the environmental impact of it. •Solar panels require lots of water. for cleaning. •Where does the water come from? •How do we pump it? •How much will that cost? •What do we do with the grey water? Recycle it? -How will it affect the wildlife? •Even though a desert may be. inhabitable for humans there is probably a great deal of wildlife who's entire world revolves around the desert. So how will covering an entire desert in shade affect the ecosystem? -Even if we conclude solar panels won't have a negative environmental impact, we need to make sure the construction won't have an impact either. All those trucks and machines could disrupt the fragile ecosystem that's inplace. -Also solar panels are still new. Every year they get more and more efficient. So at what point do we start replacing the panels with new ones? -How much will replacement cost? -Where do we get funding for that? -Will there be any environmental impact when we begin replacing the panels? Again all those trucks and stuff. All in all its not cheap and we could be potentially disrupting vital ecosystem. And if there are any endangered species involved it would be even more difficult to get the green light. I should note I'm no expert. We discussed this in class the other day and I'm just posting what my notes say. Also this is on mobile so sorry for spelling grammar or formatting errors",
"Cost, maintenance. And the real kicker: transfer losses and storage. Not enough people would live near by to be able to maintain it cost effectively. Sand can cause wear and tear on \"things\" so you would have to engineer around that. And no major population centers nearby deserts, typicall, so the amount of power lost on the wire would be very high. And storage: would still need to produce power at night. So a hybrid approach would be cool. I don't know why they don't put solar collectors on the outsides of the windmills.",
"In addition to all the other replies that focus mostly on a technical and economical perspective, there is also a whole other one: If even your country alone (let alone the world) relied on one single source of electrical energy, you're going to have to invest a lot to make it secure and reliable. Imagine you built a giant solar farm in the Sahara desert to power your country (let's say Italy). Your power is now being imported from a different country. You might have contracts with them that permits you to use this power generated in their country, but what stops a corrupt government or revolutionists to cut your power? You may guard your solar farm, but if it's big enough to power your whole country, you'll need lots of guards. Such a project would also be easily attackable by terrorists, so it's really insecure. With that aspect alone, how would you find investors? Likely nobody would want to invest in an energy source that's so likely to be taken over by rebels or terrorists.",
"1_ it is being done in Morocco and other countries. 2_It doesn't need to be that sunny to generate electricity, Germany generates more solar power than the USA even though southern USA is way hotter than Europe. 3_ AS prices for the panels drop, it will happen.",
"It would be better to cover up drinking water resevoirs with floating solar panels as you help save water from evaporation and use space closer to a city",
"The Transmission grid is much more (complex / fickle) than you think as well. You cant just simply pump a few electrons through some metal and have everything work. All of the load must be managed instantaneously with the generation. This equation not only includes the amount of power but the frequency as well. The utility has to constantly manage the fluctuating frequency of the load on the grid. Which is not consistent with solar or wind. In the US its around 50HZ. The frequency your electronics run on. If this gets out of wack the whole grid can collapse. Its issues like this that cause renewables to be a much more problematic energy source than the general public understands. Source: I work for large utility and renewable are a pain in our ass.",
"* Solar panels are expensive. * Installing and maintaining them is expensive, especially in remote areas, especially with dust and not much rain - you want to clean them. * Cables to connect them to the grid are expensive. * The sun doesn't shine 24/7, you need some storage system or other electricity sources in addition. * There are projects in deserts, but they are not very cheap.",
"WE CAN. in 2008 a 500ish billion project called desertec was launched by Germany, the EU and a bunch of other investors to build exactly that in the sahara. However unfortunately as the project was getting started the Arab Spring happened. (in 2011 people got very unhappy with there goverments in the Arab world and started lots of revolutions and wars) So people got scared and thought it would be to risky to build in those countries. It is however now picking up pace again and north African countries are starting to build huge solar farms (with some being solar thermal which even generate at night) but they want to power there own people first. Similar China has built a huge 2000 mile HVDC transmission line from the western deserts to its coastal cities so that the can start building solar farms there. Other projects being done to bring energy from far places to places where people live include HVDC lines linking volcanoes in Iceland with Europe so they can send Geothermal power to Europe.",
"Aside from the moving and storage problems, there's the whole environmental impact and simple maintenance. You'd need a TON of solar panels to create enough solar power for everyone, which means you build a giant solar farm out in the desert. This jacks with the local ecosystem. Then you need to keep the panels clean so they can operate at maximum efficiency. That means you need a lot of water to clean them. If you set these up in the open desert...where there really isn't a lot of water...now you have to ship water in just to clean them. Then there are the solar plants that use giant mirrors to reflect sunlight to then heat up water for steam generation. These things also take up lots of land, which then negatively effects the ecosystem. Birds literally get fried in the air if they fly into one of these, and the heat generated creates a giant warm air updraft that messes with planes. There's still a lot to work out. I think having massive solar farms out in the desert is impractical. I think the real solution is having a combination of solar and wind generation on your own property with battery storage. It's the only thing that makes sense.",
"Two reasons: 1. Electric power is lost if not used or stored immediately. We often want to use electric power during hours when the sun isn't shining. Storing power it is expensive and difficult (but we're getting better at it). 2. There's a significant amount of power loss that comes with transmitting electric power across long distances. High-voltage lines are more efficient, but longer lines experience more losses, so it's not practical to generate power in the Sonoran Desert for consumption in New York.",
"Just the cost to install would be mind-blowing, let alone maintenance. The approximate cost to install solar panels is $3 to $10 per watt generated. It's a large range, but it really depends on the quality, amount, and area you're installing them. The current worldwide power usage is about 340 watts, so the cost for solar panels is between $1,000 and $3,400 per person. That seems pretty reasonable until you realize there's 7.5 billion people on earth, so you're looking at a cost of $7.5 trillion to $25.5 trillion. That's just to install the panels, it doesn't even cover the cost of the land, the labor, or the maintenance of the panels. And that's even ignoring the cost to transport such a large amount of power around the globe. I know what you're thinking... so what about just the United States. Well that 340 watt per person figure was worldwide, if you take just the United States into account then you're looking at 1380 watts or approximately $4,000 to $14,000 per person. At a population of 319 million, you're looking at approximately $1.27 trillion to $4.47 trillion... again just for installation.",
"URL_1 Read this and you'll learn why... URL_0 It's not very effective. Look at the comparison from the solar panels to Palo Verde Nuclear Power Plant.",
"If this would work then how much better would it be to put billions of solar panels in space between here and the sun and have them just beam the energy to earth.",
"Actually, you dont need any solar panels to provide the entire world with unlimited electricity. All you need is a single cable. Run the cable north to south. That cable will pick up solar radiation and generate electrical current through it. This has been known since Galileo's time.",
"I would rather see power production move smaller scale than larger. In a perfect world, every house would have its own power plant. It would be a consideration when buying a house and would be something to maintain on your own, just like your roof, furnace or water heater. I know for regions without a lot of sun or wind the tech isn't there but I'd like to see the push in this direction.",
"We send electricity through wires from power plants to our home. The energy (electricity) that we add to the system is equal to the energy taken out of the system, **minus** electrical friction (heat) losses. The longer the distance from the power plant to our home, the more heat energy that is lost in the transfer process. To transfer from deserts to the world would cost too much in terms of energy loss to be benefitial.",
"We will be able to do so, someday. HVDC is a cheaper way of transmitting electricity than HVAC if the distance is *large enough*. [source]( URL_1 ). There are new batteries being developed that should be *safe* and *not-environmentally-disastrous*. [source]( URL_0 ) My guess as to why we are not doing it right now is that there is already a lot of money in other forms of energy and not enough incentives to go full solar. When I speak of incentives I mean the sum of all the factors that could make full solar, today, less profitable than other forms of energy.",
"Don't know if it's been mentioned yet, but deserts are also full of sand and wind which can scratch and damage the surface of the panels at worst, and at best require regular cleaning There are robots you can hire if you have large enough farms but they would need to be in constant use and power would drop during sandstorms Night is also usually very cold in the desert, so the big change in temperature on a daily business from high max operation temp to low 0-production temp is an engineering challenge in itself TL:Dr harsh environment = damaged components and maintenance costs",
"Intermittency - the sun goes down at night and cloud cover is still difficult to forecast more than a day ahead. Location - the cost and losses involved in transmitting electricity from the sunniest regions to the least sunniest regions makes the enterprise unviable. Engineering - the grid can't handle it, you need responsive energy generation to handle peaks and troughs in demand. Investment - Leaving the aforementioned problems aside, it would be disastrous to invest the enormous sums needed to scale up solar PV only to find that more efficient solar cells were developed a few years later, or some other innovation rendered the solar fields obsolete. Energy return on energy invested - Solar is currently way behind Wind, which still slightly lags behind oil (although the newest, largest turbines are catching up)",
"Many of the comments highlight the logistical issues with this but there are also environmental impacts as well. While many people think of places like Arizona as just massive deserts with nothing living there, deserts are home to many different flora and fauna. Here's a [link]( URL_1 ) some of the various wildlife present and another [link]( URL_0 ) showing the variety of the different types of desert ecosystems in Arizona. To make room for a solar farm you'd have to remove a large portion of these ecosystems to generate even enough electricity for a single city let alone the whole world. There are definitely logistical issues with covering the desert with solar panels but it would also be the same as removing a forest to make room for that level of energy production."
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5wofys | How does smoking marijuana cause tar buildup in pipes, but not so much in the lungs? | Wondering as a former toker. I have never had noticeable effects on my breathing and even ran a mile at the track with my fastest time ever. After I quit, nothing changed, I never coughed up any lung butter. So, how do lungs deal with marijuana tar? Or am I just deluded? | Biology | explainlikeimfive | {
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"It actually *does* gunk up your lungs. Some studies suggest that pot smoke is significantly worse for your lungs than even tobacco smoke. It doesn't build up to infinity because your lungs have a significant self-cleaning ability."
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5woh5s | Are most natural remedies for everyday ailments Placebo? Do random roots or spices actually have powerful healing properties? | Biology | explainlikeimfive | {
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"A good rule of thumb: If alternative medicine was proven to work, it would simply be called \"medicine.\" For very minor aches and pains, it's possible some some herbal remedies are very, very mildly effective. For the most part, it's a combination of placebo and very mild positive effects.",
"Some are - some aren't. As Slackador says, \"if it were proven to work, it would simply be called 'medicine'\", and that's true up to a point. It not only has to work - it has to be be as good as, or better than, other stuff that's on the market to make it worthwhile to make into an 'ordinary medicine' (with all the regulatory hoops to jump through). But some 'random roots' make it: Aspirin from willowbark and meadowsweet Digoxin/digitoxin from foxgloves Atropine from Deadly Nightshade Morphine (and other opioids) from the opium poppy Vinca alkaloids from one of the periwinkles The taxanes from yew trees to name just a few off the top of my head. The US NCCIH has a useful website with some basic information on a small selection of herbs here: URL_1 The best website I've ever found is URL_0 - but you have to pay for access. But a lot of herbal remedies have no evidence backing them up for what they're used for. It's also worth remembering that if anything has good effects, it probably also has side effects. I remember looking at a 16th century herbal a few years ago - and some of the herbs it listed might have worked for what the book said, some might have had effects but not for the diseases listed, and some we that we're not aware that they have any effects at all.",
"> Do random roots or spices actually have powerful healing properties? Some certainly do, but most of the ones that are known to have medical benefits have already been thoroughly researched, and their medicinal properties distilled into pills or other medicine. Aspirin, for example, came from the leaves of a willow tree. It's entirely possible that there are other remedies that haven't been discovered and mass produced yet, but don't trust every \"herbal remedy\" you see posted online. Many of them are snake oil.",
"Not necessarily. There are natural sources for quite a few actual medicines. Willow bark has been used for centuries to reduce fever, and was a precursor used by Bayer to develop Aspirin.",
"Aspirin is a tree bark compound, and it has some pretty interesting properties. Nobody in the herbalist community is doing things with \"random roots\". On the other hand, if a plant compound has proven effectiveness, it gets extracted and put into traditional medicines. What's left for the \"natural remedies\" section of the drugstore are plants with small effects **plus** the power of suggestion that a natural solution would be more comforting."
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5wopg0 | Since placebos work, why can't we reproduce similar results just with sheer willpower? | My understanding is that placebos can cause positive results without actually 'doing' (for example, creating a chemical reaction) anything. So why can't the mind produce similar results just by itself? | Biology | explainlikeimfive | {
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"I do this with hangovers. You just need to convince yourself that you didn't get drunk last night, and that its just a slow morning and voila, you still feel shit.",
"I am not sure what you are asking... the placebo effect is the result of the mind producing the perceived result, it quite literally already is will power.",
"The weird thing about this is that placebo effect is mostly subconscious while utilizing willpower is a very deliberate action. In a successful placebo experiment, the pill/injection is administered and the recipient goes about their day essentially waiting for it to take effect and the desired results are produced. Willing something into existence requires a lot more active engagement so the two are hard to compare.",
"I guess you could, but maybe the lesson here is that we're just not very good at lying to ourselves."
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5wosrs | What do actors actually snort when they film scenes of snorting coke? | Other | explainlikeimfive | {
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"Powdered lactose or vitamin B powder. If they snort it through a straw or something they coat the inside with vaseline so it gets stuck in the straw and most of it never reaches their nose.",
"Sometimes actual coke, but normally it's powdered lactose. It would only be actual coke if the actor made that switch himself. For example in Grandma's Boy the actors replaced all the fake weed with real weed."
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5woy01 | Why does binary use 0 and 1 instead of 1 and 2? | Mathematics | explainlikeimfive | {
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"The same reason our base-10 number system uses 0, 1, 2, 3, 4, 5, 6, 7, 8 and 9. There is no symbol 10 in base 10. Any base has symbols up to, but not including the base you say it is. So base 10 has symbols up to 9. Binary has all the symbols up to 1.",
"Because it makes math work. Let's look at decimal (base 10, \"normal\") numbers: if I have the number 104, it means I have one hundred, zero tens, and four ones (or 1 \\* 10^2 + 0 \\* 10^1 + 4 \\* 10^(0)). Binary does the same thing, except with \"2\" as the base instead of \"10\". So 1001 in binary is (switching back to decimal here) 1 \\* 2^3 + 0 \\* 2^2 + 0 \\* 2^1 + 1 \\* 2^(0), which adds up to 9. That doesn't work if you use 1 and 2 instead of 0 and 1.",
"Really it uses \"off\" and \"on\", this is just represented as 0 and 1. Representing \"off\" as \"0\" makes a lot more sense than representing it as \"1\".",
"There are three reasons I can think of, two of which have already been mentioned. One is that the binary number system just doesn't have the symbol '2' in it. '10' is a perfectly adequate representation of two in that system. The second is because at the end of the day all that really matters is there's an ON/OFF, YES/NO, TRUE/FALSE dynamic going on in the circuits of the computer. There's only two possible states the electronics can be in; call them whatever you want. But it makes sense that 0 should be one of them so we can note that the passive, \"default\" state of the computer is one thing, and then the \"1\" represents the alternate, changed state. The third is that it actually has some use for logic and data analysis. To use an example from the class I should be studying for, imagine that you're trying to create a math equation for a computer program that could predict whether someone will not be able to pay back their loans. You have an equation that looks something like: probability_of_default = 0.25x(person_is_student) + 0.0003x(debt) The word \"debt\" just represents the amount of money they borrowed. But the word \"person_is_student\" represents whether or not that person is a student. If you express it as 0 for \"not a student\" and 1 for \"is a student\", that's super useful because it means that part of the equation all multiplies to 0 if the person isn't a student, which is what you want. If you tried to use 1 and 2 for student status, you'd have to code extra lines to tell the computer to check if the number is \"1\" or \"2\" and do different things accordingly. Making something go away by multiplying by 0 in one case is a lot easier.",
"You still need to represent zero with binary numbers. The symbols used are honestly arbitrary, you just need enough symbols to cover the size of the base. But all systems need to represent zero because it's part of the range the number system needs to express."
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5woz2i | Do brands like Coca Cola, Pepsi etc. still work on refining their recipes, or are they using the same they did 10 years ago? | Chemistry | explainlikeimfive | {
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"History (such as \"New Coke\" and various other products which come and go) suggests that they do, but that such experiments are incredibly closely guarded. I think that after \"New Coke\" it's fair to say that they don't fuck with their core recipes anymore, but they spin off new flavors and variants from them, which probably comes from fiddling with their core recipe. So yes, and no."
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5wp7x3 | Why does the body allow us to sleep in positions that cause us pain in the morning? Such as waking up with sore necks, arms, etc.? | Shouldn't we unconsciously realize that it is uncomfortable and re-adjust? | Biology | explainlikeimfive | {
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"I have been waiting for this moment my whole life. Sleep Expert here. The reason one does not feel pain while they sleep is because when you sleep, “most neurons in the brain stem immediately above the spinal cord, reduce or stop firing.” The brain stem is composed of the medulla oblongata, pons, and midbrain. The brain stem is in a way, a highway where the motor and sensory system passes through to the brain. Therefore, while awake, the nociceptors, which is a type of sensory neuron which is active when there is tissue damage, and is what causes the pain sensation, is traveling from the point of damage through the brain stem to the brain. So, while asleep, there is no brain stem connection to the brain from the sensory neurons, ergo no pain perception. You can think of it as connecting Christmas lights. When you connect one series of lights to a second series of lights, it will allow electricity to flow through both sets. If you disconnect the second series of lights, then the flow of electricity will only flow though the first series of lights. As opposed to 1998 when the undertaker slammed mankind through the hell in the cell on a 16 foot drop. After which my dad beat the shit out of me with a pair of jumper cables. Edit: this also explains why they knock you out for certain surgerys Edit: TFTG. Also, side note of fun. You guys remember the trick of putting a sleeping persons hand in warm water and it makes them piss themselves?",
"People don't necessarily notice an uncomfortable position when conscious. Have you ever unbent your arm after a long telephone conversation? (Oh god, do people even still have long telephone conversations?)",
"Why should we? Sleep is important, maintaining that bit of extra awareness of our comfort is taxing. Consider obstructive sleep apnaea. This is essentially your body occasionally just waking up just enough to move slightly and correct your neck's position so you can breathe clearly. But it's a serious sleep disorder that can cause all sorts of performances issues during the day. And it's all caused by being minorly woken up due to a condition that would otherwise cause you to suffocate. Now, with being unable to breathe, yes, we do wake up, readjust and don't die in our sleep. But it has a huge toll, and a pretty obvious trigger. Are we becoming hypoxic? Ok, then trigger something to rouse us a bit and gasp for breath. If our body were to do that every time we got uncomfortable, first of all, it's much harder to define discomfort, especially stiffness that isn't obvious until you actually get out of bed. Secondly, it would ruin our sleep quality almost every night. So we fall asleep in a position that is comfortable when we fall asleep, and unless we have some other sleep issue, we don't move around too much when we sleep. We wake up with minor aches maybe if we were in a weird position, but we walk it off. The alternative is to wake up constantly in the night and never sleep properly. As someone who suffers from sleep quality issues, I would always take a better night's sleep over a few aches in the morning every time.",
"Something that I do not think has been mentioned and is based on science and not conjecture or anecdote is the fact that the brain releases the equivalent of a paralytic when humans sleep, particularly during REM sleep. It was initially thought to be caused by the neurotransmitter glycine, but is now thought to be two types of GABA (also neurotransmitters). Basically, they effect the muscles, preventing movement during sleep. This is probably a large part of the answer you are seeking. Sources: I'm a neuroscience student",
"The reason it hurts isn't because the position is uncomfortable, rather it's because moving AWAY from that position is. While you sleep your body subconsciously keeps you from moving in the particular way that hurts, but once you're up you're much more aware and therefore it's much harder to not move a certain way, hence the pain.",
"Many positions can be comfortable for your body for a short period of time, but after a few minutes can cut off circulation or strain a muscle or tendon that causes numbness or pain. Your body moves into one of these awkward positions because it feels great at the time, and it's not until you regain some level of consciousness that your body will adjust. Your brain is in sleep mode and is not thinking through \"what is the most comfortable position I can sleep in that won't cause me pain when I wake up.\" Your body is just finding a position that feels good right now, and does it for you to deal with the consequences later.",
"Typically in this situation, it is not the position that causes the pain or else you would indeed wake up. Almost always the pain is related to something that happened to the body during the day and then when you lay down to sleep the inflammatory/healing process settles in and results in pain upon waking up. But there are of course exceptions.",
"I know no one asked but I can't sleep unless I put myself in a very specific position. That really annoys me because I'd love to know why, if anyone is competent on the subject and feels they can conquer this task, please let me know why.",
"When your body enters REM sleep your muscles completely relax like a ragdoll and you might settle into an awkward position that you wouldnt have intentionally positioned yourself in.",
"Who knows. The body is weird. For example, while I was in the womb my head was stuck tilting / turning to the left until I was born. To this day, I still have much greater ease looking to the left than right, and always end up with my neck craned to the left while sleeping. My neck always hurts.",
"Imagine waking up every single time your body moved into a position that might \"ache\" a bit after a nice 8 hours of sleep. Sometimes I wake up with my arm completely numb because I slept on it. So i grab my arm with my other arm to lay it on my stomach and let blood flow back into it after a few minutes because I literally can't move it haha. But things like that make my calm sleep worth it. And the occiasional neck pain is worth it too eh."
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5wpapu | How do Blu-ray Discs know where I stopped watching the movie, even if I restart it on a different player? | Technology | explainlikeimfive | {
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5wpjbt | Why and how does cancer spread and how do the mutations happen to the cells? | Biology | explainlikeimfive | {
"a_id": [
"dec7cka",
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"text": [
"Probably not an appropriate response for an ELI5 but it's too good a book to ignore: Check out A Biography of Cancer - The Emperor of All Maladies. Riveting, epic stuff and I believe winner of a Pulitzer Prize for non-fiction.",
"Its caused by mutations in the DNA after birth - from harmful chemicals mainly, UV radiation and ionizing radiation. A cancer is made out of cells that divide uncontrollably. When some of those cells get picked up by your lymph system, they can get transported to your lymph nodes and then to other organs in your body. They continue reproducing uncontrollably, so the new place they land in now has cancer as well. How it kills you: Cancerous cells will do a few things that are dangerous. First, they divert resources to themselves. They take up sugar and oxygen from your bloodstream and give nothing in return, which weakens your body and leaves it vulnerable to infection. Sometimes tumors even cause blood vessels to divert to them in a process callef angiogenesis. One of the warning signs for cancers are sores that don't heal, because your body is so weak it can't do simple repairs anymore. Second, cancerous cells will invade and attack surrounding tissues, damaging them and impairing function. Thirdly, tumors gunk up your system and physically impair normal function. A tumor in the brain can put pressure on the brain, restricting blood flow and causing brain damage. Leukemia can be so bad the blood becomes watery and pus-like because healthy cells are getting crowded out by cancerous cells. Finally, some cancers are malignant, meaning the start in one place and then colonize other parts of the body. For example, breast cancer might be bad, but if it stayed in the breast it probably wouldn't kill you. However, if cancerous cells migrate out of the breast to vital organs, the risks shoot up."
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5wpjum | Why do Mount Everest Climbers not go/climb around the Khumbu Icefall? | I've been watching a lot of Mountaineering documentaries but I know nothing. Halp. | Other | explainlikeimfive | {
"a_id": [
"debxtd4"
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"text": [
"Plenty of climbers do - anyone who takes the [North Col Route]( URL_0 ) avoids the Icefall entirely. The main troubles with that route are that it's longer and more difficult, and that it starts on the Tibetan side of the mountain, which was closed to foreigners for decades. I'm not actually sure how easy it is to get into Tibet nowadays. So for those reasons, the South Col route is the better-known and more well-traveled. The Icefall is dangerous, but it's really the best and easiest way up the mountain from that side, so climbers just have to take precautions to make it as safe as possible."
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5wpk6g | What is the mechanism by which daily exercise lowers blood pressure? | Biology | explainlikeimfive | {
"a_id": [
"deca86a",
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"text": [
"So basically this concept revolves around the fact that your heart as a continuous pump. Your arteries contain muscles that work the same as any other in your body: the more that you exert the muscles the stronger they become. When exercising the heart and arteries are forced to pump blood at levels higher than they would normally function (i.e. an increased heart rate and blood pressure), and as a result they both get stronger. As the muscles grow stronger they no longer need to work as hard to pump the same amount of blood throughout your body. This leads to both a lower heart rate and blood pressure blood because blood can now be pumped more efficiently. Systolic blood pressure (the top number of blood pressure that measures pressure on arteries while the heart is beating) is lowered because your body no longer needs to put as much pressure on arteries to pump the blood. Also, diastolic blood pressure (the bottom number of blood pressure that measures pressure on arteries while the heart is resting) can be affected a little as well from exercise but not as drastically because the heart improvement from exercise no longer affects this pressure.",
"Blood pressure is the net result of how powerful/fast the heart pumps, and how healthy the blood vessels are. I did a lot of research on the state of blood vessels during exercise in healthy/obese people during undergrad. Regular physical activity makes your heart stronger, that now can pump more blood with less effort. If your heart can work less to pump, the force on your arteries decreases, lowering your blood pressure. Blood flows faster through the blood vessels during exercise. The increased friction forces of the flowing blood during exercise stimulate cells in the inner layer of the blood vessels (endothelium), causing the blood vessels to widen up (vasodilation). The main reason for this is to increase blood flow to the exercising muscle. It also keeps the blood vessels healthy, by keeping the blood vessels elastic. It also prevents the build up atherosclerotic [plaque]( URL_0 :) , which is a greasy mess of (calcified) fat, dead cells and white blood cells covering the arterial wall. What we often see in persons with a sedentary lifestyle and poor eating habits is that they have high blood sugars, high blood pressure, and their blood vessels are in a bad state (build up of plaque prevents exposure of endothelial cells to the blood stream). Now, try to look at the blood vessel as a long metal pipe. Every time when you pump an amount of water, the water pressure at the end of the pipe is just as high as the beginning of the pipe because the pipe is just a stiff piece metal. What you'll see is: water comes in the pipe as a pulse, water comes out as a pulse. When you make the metal pipe narrower in the middle (build up of plaque), you'll need to pump the water with much more pressure in to the pipe to get the same pressure at the end of the pipe. This will be your unhealthy blood vessel, causing high blood pressures (for instance 160/110 mmHg). A healthy blood vessel will be a long cylindical balloon with the ends cut off. Every time you pump water in one end of the balloon, the balloon will expand where the water bolus will be (your vessels are elastic too). This results in a more evenly distribution of the water pressure after each pulse downstream, evidenced by a more constant water stream at the end of the balloon and normal blood pressures (115/80 mmHg). When you're healthy, exercise won't do a lot for you in terms of lowering blood pressure. But it will do **a lot** for people with high blood pressure/diabetes/heart failure, especially in combination with changes in food intake and moderation of smoking/alcohol. Don't be a couch potato, exercise regularly and eat healthy"
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5wpnlm | What appears between gaz molecules when its density lowers | If a gaz is inside a box and if we enlarge the box, the number of molecules will stay the same and the gaz will dilate. So what will be between the molecules of the gaz? | Physics | explainlikeimfive | {
"a_id": [
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"text": [
"Empty space. That's why gasses need so much more space than an equal number of molecules in a liquid or solid form. There is a lot of space needed because of their high temperature.",
"> So what will be between the molecules of the gaz? Nothing is between the molecules of gas. It is vacuum.",
"The same number of molecules will travel around in the larger of space. This is a decrease in density. You can think of it like a half court game of basketball. Ten people are running all over half of the court. If it then becomes a full court game the same ten people run around twice as much space."
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5wpt00 | Typically what causes 'sudden weight loss' when someone has a disease? | Biology | explainlikeimfive | {
"a_id": [
"dec1xzr"
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"text": [
"Fewer calories in, more calories burned, stuff breaking down, or fluid loss. Under more burned, we have things like hyperthyroidism directly increasing basal metabolic rate; nearly every cell in the body is affected to some degree, basically cranking up energy usage. Malignant tumors are notoriously hungry for glucose, and will steal it anywhere they can. Under less in, we have appetite suppression, which can happen a lot of ways, and malabsorption, as seen in enzyme deficiencies, some gastrointestinal issues, etc. Uncontrolled diabetes may mean simply peeing glucose out. Breakdown of fat and muscle gets more complicated, so let's just say it happens. Any kind of serious dehydration, often from vomiting and/or diarrhea, can shed pounds very quickly. (The treatment for cholera is largely \"measure how much water they poop out, then give them that much oral rehydration fluid.\") Those diabetics who are peeing glucose out are also losing a lot of water with it; people in diabetic ketoacidosis can require many liters of fluid when hospitalized."
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5wpwnc | The purpose of the scrotum is to keep sperm at a lower temperature. But then sperm are expected to live up to a week inside a body with an elevated temperature during ovulation. What gives? | Biology | explainlikeimfive | {
"a_id": [
"dec1w6d",
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"text": [
"The *production* and ongoing survival of sperm are different biological processes. The testes are outside the body to keep temperature lower to assist with the *production* of sperm. Also, a lower temperature may offer an improvement in sperm survival, but this does not mean no sperm can possibly survive at the higher temperature inside the body. Meanwhile 5 days survival in the female body is less *typical* and more cautionary, that is to say it is a set of circumstances that *could* cause pregnancy. Not that there is an especially high portion of sperm still active or likely to cause pregnancy after that time period.",
"Lower temps are optimal for sperm cell production, not absolutely needed for grown sperm lifecycle."
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5wq4a3 | Why isn't there toothpaste that's "Whitening" & "Enamel protection" & "3-in-1 plaque defence" etc. Is there actually a big difference between them all? | Chemistry | explainlikeimfive | {
"a_id": [
"dec6ulm",
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"text": [
"So, whitening toothpaste and to a much greater extent the professional whitening treatments are pretty hard on your enamel and can damage the teeth the roots, which is the exact opposite of the enamel protection. Think of the enamel protection as something like putting polyurethane on a table and the whitening is like scrubbing it or even sanding it. Those two things don't really work together.",
"Why don't we have cookies we can eat that clean our teeth?! Seriously, dogs have it!",
"I've been a little depressed ever since having to use the sensitive-teeth stuff. It works, but is expensive, and the generic has almost no minty freshness. Ahhh first-world problems."
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5wq629 | What makes the Caribbean Sea so clear? | Compared to other bodies of water around the world, I can't think of a single one that is so clear, or has such a distinctive shade of blue. | Chemistry | explainlikeimfive | {
"a_id": [
"dec47zv"
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"text": [
"The water in the Caribbean appears blue because it absorbs the red, yellow and green wavelengths of light while reflecting the shorter blue wavelengths of light. The Caribbean water is very clear due to the absence of suspended particles and plankton, further increasing the blue color. [Info taken from here]( URL_0 )"
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5wq70f | Do editors at big movie studios use commercially available software (Premiere, etc) to edit big budget movies or do those studios have proprietary software they use? | Technology | explainlikeimfive | {
"a_id": [
"dec4gts"
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"text": [
"Avid is the most popular choice or sometimes Final Cut Pro(I think that one has become less popular). Those are both commercially available, although they're a little pricey."
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5wqm24 | The pros and cons of physical versus virtual money. | Economics | explainlikeimfive | {
"a_id": [
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"text": [
"Physical Money Pros: * No technology is needed to exchange money and make sales * No internet access is required * No record of transactions (some people use this for tax avoidance) * The other person cannot track you (with a credit/debit card if they find out who the card belongs to they can check all of their records to see when they have done transactions with you in the past) * You cannot get hacked and lose money Virtual Money Pros: * You only need to carry around a card or your phone * You can't lose your money or damage it (although if you lose your credit card someone could steal it and spend your money) * Does not require the Bank of England to print bank notes * It's quicker to pay for things if you just have to put your card up to a card reader than if you have to get cash out and count coins. This can actually save quite a considerable amount of time. * Harder for criminals to use as they don't want to be tracked (although they can use bitcoins) * It's safer to carry around than physical money as if you get robbed, the criminals could run off with your notes and you'd never see them again, but with virtual money you wouldn't lose anything until they use your credit/debit card, and your bank could even block their transactions if gets suspicious of fraud on your account"
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5wqpl1 | How was the German Empire able to hold off Britain, France and Russia, at the same time on two separate fronts and even pushing them back during World War 1 | Was it the brilliance of the German army, Prussian traditions or simply errors by the Entente etc.. I also looked at the population figures and the Entente had double the population of the central powers (excluding colonies) surely they could have overwhelmed the central powers just through sheer manpower? | Other | explainlikeimfive | {
"a_id": [
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"text": [
"Mainly, The germans early were prepared for war. Hell when It first kicked off the british didnt even expect anything to happen and treated it like a show of power for political prowess. So A well supplied motivated german force was more than a match to what opposed them. Also trench warfare heavily favored the defenses. Imagine mini normandys every time you attacked a well fortified line. Armor was basically non existent and artillery had more effect on morale than actually causing physical harm. Thats my 2 cents.",
"Germany had beaten France pretty bad as \"Prussia\" in 1870 previously. This \"humiliation\" was a big part of French animosity to Germany leading up to WW1, exacerbated by Germany only getting stronger since then. So Germany felt pretty confident they could beat France 1 on 1 again. Britain had a small standing army. Surrounded by water and primarily concerned with overseas colonies, they had always primarily been a naval power. Russia was a sprawling empire with poor infrastructure. And large sections of \"Russia\" weren't really Russian and had honestly only recently been brought under the tsar. It would take them a long time to assemble their army and get them in position. Germany knew this and their plan from the start was a rush to Paris to knock France out of the war (and effectively, they thought, England because where would England land its army?) and then turn around and beat Russia. This almost worked. They Germans beat the French up pretty bad but France made a famous stand near Paris (they used Parisian taxis to bring troops to the front) and the Belgians somehow managed to keep a small force intact and linked up with the small British force they had on hand. This could have spelled disaster except Hindenburg/Ludendorff won a fantastic battle in the Prussian forest against a much larger russian force delaying the Russian (who assembled an army faster than Germany anticipated). At this point Germany realized their original plan was toast. Because the western front (with France/GB) was smaller they decided to strip it of troops and just \"dig in\". This is when the famed trenchbwarfare began. They used all of the excess troops to fight Russia. It's important to note that Germany wasn't alone verse Russia. Austria-Hungary was an ally and lost hundreds of thousands of soldiers fighting Russia as well. Though the performance of their army declined as the war dragged on (and eventually collapsed) they were intergral early on and bore the brunt of Russian attacks after 1914. Eventually, as I'm sure you know, Russia ate itself from the inside with the communist revolution, which allowed Germany to refocus on the Western Front. Sadly for them, by then the US had joined the war. Edit - Accidently wrote \"Soviet\" in here when referring to the Russian empire",
"Mostly it was that the German Empire was already prepared. They knew war was coming, they just needed an excuse. France suffered tremendously just 40 years before during the Franco-Prussian War. The country wasn't eager for more war and wasn't particularly preparing for it. England also just had a miserable war in Crimea. It was disastrous. They weren't totally prepared for another war on the continent. And Russia was going through significant domestic strife because the Czar couldn't politically modernize and the Communists weren't happy. Hard to fight a war when there's political turmoil at home."
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5wqrze | how bad it is for me to not thoroughly chew my food? | I basically chew just enough to lubricate and swallow. All I know is that Ive been doing this my whole life and always have really stinky farts. Not sure if the two are related. | Biology | explainlikeimfive | {
"a_id": [
"decf11s"
],
"text": [
"It isn't bad and not even remotely related. Chewing helps the digestive system process food more efficiently but you probably won't notice it even if you don't chew at all (just don't do that too often). Stinky farts have more to do with the food you eat, and the bacteria in your intestines. Those bacteria help you with digesting the food, but produce waste products and gases at the same time."
],
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5wr0bh | Why are consumers so hell bent on paying the least amount of money for something, but then complain about the methods of how the company reduced its prices? Like, "bring our jobs back to this country, but don't raise prices, damn you!" In the end, it's the consumer who drove the jobs out. | Economics | explainlikeimfive | {
"a_id": [
"decbj3q",
"decbj2j",
"decd9p0",
"deccufx"
],
"text": [
"Most people don't have a good grasp of macroeconomics or the effects of consumer choices on production. People want what they want - they want high paying jobs for themselves and they want everything they buy to be cheap. They don't understand that these two things are not compatible at a macro level - they just want it.",
"People want change but only if it benefits them and they don't have to give up anything for it. It's much easier to listen to someone that tells you there's a simple solution to problems than someone that tells you like it is (extremely complicated and without easy painless answers)",
"The same reason you didn't pay a management consultant $2,000 to answer this completely with a full color report, rather you asked for answers from people who may be DJs with a suit for all you know. People want to get something for nothing, especially when it's diffficult to evaluate quality.",
"This is an awful, emotionally charged question that just looks to affirm what it already thinks and mock other people \"why do people complain\" why don't you ask those people"
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5wr8ld | Why are people allowed to create covers of famous songs and sell them/put them on Spotify? | I see a loooooot of covers of songs from series like Steven Universe or Anime as well, is this even legal? | Economics | explainlikeimfive | {
"a_id": [
"dechd5o",
"decuswr"
],
"text": [
"In addition to what others are saying, if you get permission first you may be able to negotiate a lower royalty payment. A songwriter in the US does have the right to dictate who will be the *first* artist to use his/her song. After someone does it once, though, anyone else can do the song as long as they pay a royalty. Weird Al almost always comes up in discussions about this. He doesn't *have* to get an artist's permission to do a parody of their song, but he waits until he has it as a matter of courtesy. Two famous miscommunications in this: he parodied Coolio's \"Gangsta Paradise\" not knowing Coolio's reps have given their blessing without actually checking with Coolio. And he couldn't believe how stubborn Lady Gaga was being about him doing \"Born This Way\" until the issue started getting press coverage, thanks in no small part to his tweeting about it. Turns out that like Coolio, her people weren't actually asking her. When she found out she was honored and gave the green light.",
"You pay a licensing fee to the song writer. My sister's band released a cover of a Taylor swift song. Every time someone downloads that song, they have to give a percentage of the money to Taylor Swift."
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5wr9sf | Why is antibacterial soap bad? | I understand that using antibacterial soap (or any kind of antibiotics) can leave super-bacteria that are resistant and pass on the genes, effectively allowing the next generation to be completely resistant. However, wouldn't the resistant bacteria reproduce and spread their genes anyway since bacteria reproduce asexually? | Biology | explainlikeimfive | {
"a_id": [
"decdkwy"
],
"text": [
"They would, but they have to compete with sensitive bacteria for the same resources/space. Here is a post I wrote some time ago that explains the concept: Imagine this scenario: There are 100 bacteria, and 1 of them happens to be resistant. You take a few doses of penicillin, and kill 90 of them. Now, there are 10 left, 1 of which is resistant. If you finish your course, then you kill 95 of them, and your immune system kills the other 5. However, you feel better after half the course, and you stop. There are still 10 left, 1 of which is resistant. They slowly start to regrow, and go back to 100, 10 of which are now resistant. You go get another prescription for penicillin, but do the same thing. Penicillin kills 90% of the bacteria it can (keeping in mind 10 are already resistant), and now there are 9 \"normal bacteria\" and 10 resistant. Once again, you don't finish the course, and now when the bacteria regrow, 50 are resistant and 50 are not. Now, penicillin is no longer effective, since it can only kill half the bacteria. Obviously this is exaggerated, but given enough people and enough time, the same concept holds true"
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5wrb5n | If now science says that cigarettes cause deformations/mutations in babies, why did so many children arrive without any in the fifties and sixties when most men and women smoked daily? | Other | explainlikeimfive | {
"a_id": [
"decdpg7",
"decj212"
],
"text": [
"As with most things, it's a matter of degree. The risk of a baby being stillborn or with extremely low birth weight is very low. Heavy cigarette usage doubles that risk. Double a very low number is still very low.",
"Depending on the country and maybe within the country, I would also imagine that children with severe problems mentally or physically often didn't go to public schools and where \"hidden away\" to a larger degree than today. So even if there was more back then, we didn't see it. And those babies are today either dead or learned to live with the problem."
],
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5wre5a | How do web browsers in general make money when they're all free? | Economics | explainlikeimfive | {
"a_id": [
"decehl4",
"deceloc"
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"text": [
"They watch your search, browsing, and personal information and sell that to advertisers. Not your information directly per say, but kinda as a whole. Like hey Amazon everyone 18-22 is checking out that new deadpool movie. Maybe advertise that more and Amazon is like thanks bro here 30 bucks.",
"most are subsidised. Primarily by the companies running the search engines pre-selected for their users. Microsoft produces Edge (and previously Internet Explorer) to try and convince people to use Bing. Google produces Chrome to combat that and have people use Google for their searches. From 2004 to 2014 Google also paid Mozilla to have Google as the standard search in Firefox. URL_0 Since then Yahoo is paying for the privilege to have their search (essentially MS Bing) results used in the browser. Because search engines are an integral part of the browser and also something where you can make lots of ad money"
],
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"https://en.wikipedia.org/wiki/Mozilla_Foundation#Financing"
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5wri0q | What is, and what is wrong with AmazonS3? | Technology | explainlikeimfive | {
"a_id": [
"decfsz7",
"decfyni"
],
"text": [
"Amazon S3 is short for Simple Storage Service. This is part of Amazon Web Services, or AWS. AWS, to simplify, is an **ENORMOUS** pile of computing power and storage. People are able to freely rent chunks of this power as they see fit, treating that chunk of muscle as their own private server. Even better, it can scale dynamically: need twice the power for just today? need twice the power for just the next *minute*? Need ten thousand times the power for the next four years to support your growing corporate enterprise? You got it. Amazon is able to offer this for a cheap price because they already spent a ton of money building such a powerful setup made of hundreds of thousands of physical computers, and they are guarenteed that if *you* don't want the power, someone else does, and it's available to that other person immediately. They have over 150,000 major customers, including some of the biggest people on the 'web. S3 is used primarily for data storage, so lots of sites (such as imgur) use it to store relatively large items like pictures. Some sites don't run completely on Amazon's setup but just use it to store big stuff, which is why some sites would do stuff like show text but the pictures wouldn't come. Exactly what is wrong with S3? Amazon hasn't said, and they don't have to. It appears that sometimes requests for data go into the building and don't always come back out, which.... really doesn't tell us much. We kinda have to sit on our hands and wait.",
"To add: When we sent requests to the S3 server, we would get unspecified errors just telling us that it didn't work. To quote Amazon: Update at 2:08 PM PST: As of 1:49 PM PST, we are fully recovered for operations for adding new objects in S3, which was our last operation showing a high error rate. The Amazon S3 service is operating normally. Update at 1:12 PM PST: S3 object retrieval, listing and deletion are fully recovered now. We are still working to recover normal operations for adding new objects to S3. Update at 12:52 PM PST: We are seeing recovery for S3 object retrievals, listing and deletions. We continue to work on recovery for adding new objects to S3 and expect to start seeing improved error rates within the hour. Update at 11:35 AM PST: We have now repaired the ability to update the service health dashboard. The service updates are below. We continue to experience high error rates with S3 in US-EAST-1, which is impacting various AWS services. We are working hard at repairing S3, believe we understand root cause, and are working on implementing what we believe will remediate the issue."
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5wrixg | what is frequency in light? | Yup, what's that all about??? | Physics | explainlikeimfive | {
"a_id": [
"decg450"
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"text": [
"Frequency, in anything, is how often something happens in a certain period of time. Frequency in light is measured in hertz, or Hz, which is 1/s. It refers to how many times a part of the light wave repeats itself in one second, so to speak. So, if light has a frequency of, say, 100 Hz, that means the wave travels from peak to peak (or valley to valley, or midpoint to midpoint) 100 times in one second."
],
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5wrlcd | What part of the brain is responsible for our ability to quickly react to someone calling our name? | Biology | explainlikeimfive | {
"a_id": [
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"text": [
"Here's a sampling of the processes involved: 1. Who's the sender of the information? 2. Where's the sender located? 3. What tone of voice was used to call my name? 4. What historical context is there for the tone used to call my name? 5. Where are we, and what possible scenarios match the nature of the tone in this context? Now, that right there is a whole bunch of areas of the brain, all serving to generate a superposition of data that we will collapse into some event, from a successful reply/tethering with the sender, to a complete failure to make any tether work at all. Humans be weird, and our MRI-perspective simply isn't far enough along for you to ask these sorts of questions of it. Better off confusing yourself a bit here ;-) ."
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5wrls9 | What happens if you inject an EpiPen without having an allergy? | Biology | explainlikeimfive | {
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"Adult EpiPen is a single use 300microgram shot of adrenaline. 150micrograms if it's the kids one. Accidental injection into healthy adults is more common than you'd think, because people hold their thumb over the end inside of holding only the sides when they are panicking and injecting someone else. If they are holding it the wrong way, their thumb gets the hit. In terms of symptoms, this is direct from the safety leaflet: Adrenaline (epinephrine) Tell your doctor or pharmacist if you have any of the following: fast or noticeable heart beat difficulty breathing shortness of breath dizziness pale skin colour weakness tremor headache throbbing sweating nausea or vomiting sleeplessness coldness hallucinations restlessness anxiety fear flushing or redness of face and skin. These side effects are minor and short lasting. Accidental injection into the hands, fingers or feet may result in the following: fast or noticeable heart beat pale skin colour at the site of accidental injection feeling of coldness at the site of accidental injection bruising or discolouration at the site of accidental injection bleeding If an accidental injection occurs at one of these areas, seek medical attention immediately. More severe side effects can occur occasionally. They are caused by adrenaline (epinephrine) stimulating the heart and increasing the blood pressure. Rarely, these side effects can cause, for example, a stroke, lung problems or severe irregular heartbeat. Adrenaline (epinephrine) may also cause disorientation and impaired memory. *TL;DR LPT: Don't inject it for fun or you can have a bad time and only ever hold it on the sides when injecting into someone else when you're saving their life like a boss.* Edit (add on): Oh, and randomly not mentioned in their own leaflet, but we use adrenaline to cause the veins to constrict (get smaller) so we can cut bleeding down to minimum when we do stitches and stuff to fix a wound. So some people if they get a decent dose into a area at the tips of their feet or fingers with small veins in them could cut off the blood supply to the point of even losing the finger etc.",
"I don't know about dosages in a pen, but you would essentially be taking a dose of speed. Jitteriness, increased heart rate, maybe fast/racing thoughts, etc. A medical professional would need to pipe in here about what the actual dosing in a pen is and if it would be too much for a healthy adult with no outstanding medical conditions. URL_0",
"An Epipen contains adrenaline, which is a hormone produced by your body involved in the fight or flight response, and many other things like emotional reactions, anxiety, and exercise. Increased adrenaline would increase your heart rate, make you sweat, dilate your pupils, and possibly make you shaky and/or anxious."
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5wrsrk | Why does aluminum foil spark in the microwave, but doesn't when its used as the container for, say a chicken pot pie? | When I put aluminum foil in the microwave by itself it sparks and makes pretty colors. On the other hand, when I put a potpie in the microwave and its container is made of aluminum foil it never sparks. Why does this occur? Edit2: follow up question- Why does a CD in the microwave react the way it does? Here is a source to a [video]( URL_0 ) Edit: Decided to flair it as physics, could be chemistry. maybe someone could shed light on where it fits best. Thank you. | Physics | explainlikeimfive | {
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"Basically, microwaves work by generating low-frequency radio waves that excite the molecules in food. This excitation generates heat, and the conductive properties of the food or liquid carries that heat to the center of the item. Metal will reflect these radio/microwaves. This is why a microwave is basically a big, secure, metal box--so you don't cook everything in the room around you. If you put a thick piece of metal in the microwave (say, like a pot pie pan) then the microwaves are simply reflected back and forth between the pan and the walls of the microwave. However, a thin sheet of metal like a strip of aluminum foil can't withstand the energy provided by the microwaves and will rapidly heat up and ignite. The electromagnetic field in the microwave will cause a current to run through the foil, and if the foil is crinkled into sharp edges, the current will discharge as bright sparks.",
"Rounded vs. pointy sections. Crumpled foil has pointy sections. Same reason lightning rods are sharp. You can leave a spoon in the microwave in your tea or food, and probably a fork IF the tines are submerged. Don't try to to use a fork in your food with the tines exposed."
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5wsiad | How does anti-venom render venom useless so quickly? | Biology | explainlikeimfive | {
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"Venom is like a bunch of evil LEGO pieces that are designed to fit into critical spots on your cells (nerve, blood, etc). Antivenin is a collection of antibodies, which physically attach to the venom molecules like sticking more LEGO to them. The result is that the venom can no longer fit into the spots in your cells it must to have its devastating effect, and your kidneys filter the mess out for you to piss away."
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5wsmf7 | With the proposed budget increases and simultaneous tax cuts, how will the proposed measures be funded? | Examples pulled from tonight's presidential address: $1 trillion infrastructure investment $54 billion military budget increase | Economics | explainlikeimfive | {
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"There haven't been any realistic plans proposed, so you're asking for speculation. Most likely, most of the changes are rhetoric and will be dropped once the administration realizes just how hard it is to cut other things. There's basically 4 ways to pay for spending increases: Cutting something else Economic growth Tax increases Debt There's a broad belief that there is tons of \"government waste\" going on, which if we could only get rid of, we'd have tons of money left over. In reality, this isn't really the case and those gains never materialize (similarly, economic growth is 99.99999999% unlikely to hit the targets required to fund these). Not on the scale necessary for anything remotely closed to what was proposed. Higher taxes aren't even up for grabs. That leaves simply taking on more debt, which would be hard to sell (but not impossible) tldr: It won't be.",
"You'll have to believe the GOP. They have plans, they can't talk about them but, they have plans. Believe them.",
"I just can't see why we spend 500 billion on the military, and we're going to up that by 54 billion. Rediclious.",
"Presumably through public borrowing. Either money in goes up or money out goes down or we get more in debt. If someone promises you less money in and more money out then what they are promising you is debt."
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5wsmly | why does alcohol bring out emotion/violence in some people? | Biology | explainlikeimfive | {
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"A normal part of adult behavior is a result of an internal inhabition system. We are all fixated on our problems and dilemmas, but we repress the emotions attached to these inner dialogues because we realize they are socially unacceptable. When you get drunk you forget it's socially unacceptable, or more properly, your inhabition system become less engaged so you don't care it's unacceptable.",
"Alcohol is a depressant in that it reduces central nervous activity. One of the areas of the brain that's affected is the frontal lobe which is the region of the brain responsible for inhibitions. When the activity of the frontal lobe is reduced, some people will lose control of their emotions and can become violent."
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5wsmp0 | Why does an applause eventually synchronize? | It takes a while but it always happens if it's long enough. | Mathematics | explainlikeimfive | {
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"text": [
"Pressure. If I see one person clapping, I might think, \"meh\" and sit. Someone is going to start clapping with that person most likely (in certain places). Now, I have the pressure of two people subliminally telling me to clap. The reason it takes a long time is because the number of people clapping increases in a somewhat exponential way. 1, 2, 4, 8, etc."
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5wsu17 | In the cave paintings in France and Spain from 20,000 years ago, there are rinos, lions, gazelles, etc. Why did these animals go extinct in Europe but not in Africa? | Biology | explainlikeimfive | {
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"decqg8s"
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"text": [
"Climate change dealt Europe an ice age -- it just became too cold for some of these animals. Human population density limited the amount of space for these animals to live, eat, and not be hunted by humans."
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5wsu5p | What decides what elements can rain on certain planets? | What factors lead to certain elements (neon, diamonds, etc) "raining" on other planets? Is it just temperature or are there other factors? Does it look like water rain, in that there's a cloud of gaseous diamonds in the sky that fall down? Can anything be rain? Is it likely for humans to be able to visit in conditions other than planets that have water rain? (Thanks for your time--I've always been really interested in weather and never got a chance to learn.) | Chemistry | explainlikeimfive | {
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"text": [
"Pretty much temperature and liquid abundance. On Earth it's water on Saturn's moon Titan it liquid methane that falls as rain. It is so cold water is as hard as rock"
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5wsz5n | How does the human brain know this scale inherently? | URL_0 | Biology | explainlikeimfive | {
"a_id": [
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"In college I showed this to a roommate who was studying music composition. He immediately laughed out loud at how weak the guy's claim is. He starts by giving the crowd a note. OK, you've got to start somewhere. Then he spoon feeds them another note. Again, we're still establishing a premise. Then he goes on to the third note. In a pentatonic scale the interval between the first three notes is the same, so all we've established is that humans can follow a pattern. This isn't humans recognizing something inherent to the pentatonic scale; it's just pattern following. The audience doesn't even do *that* good of a job at really honing in on the third note and he has to reinforce it by singing the third note as well. We're 3/5 (someone make a voting joke!) of the way to a pentatonic scale and have barely shown the audience doing anything they weren't explicitly told to do. So now it's going to get interesting, right? The audience is going to jump on the inherent beauty of the pentatonic scale and will grab the fourth note all on their own, right? Wrong. At 1:05 he doesn't even bother with his pattern matching gig and just gives the audience the fourth note. With one note left he starts singing his little ditty. This in and of itself is quite a fun demonstration of \"playing the audience as an instrument,\" but it's also serving the purpose of feeding the audience more information about what notes are going to be in this song. The only real attempt at \"look at how the audience knows this whole scale\" is at the end where he takes the audience through a few octaves of the scale. He spoon fed 4 of the 5 notes and set up the cue of \"big leap is one interval, small leap is a smaller interval\" so by making the jump the right size he gets enough of the audience to follow the pattern and the rest pick it up soon enough. ******* With all the shitting on his demonstration that I've done, I feel obligated to point out that there is something to his claim. In music we hear the frequency of a sound wave as its pitch and we hear intervals as ratios of those frequencies. When the ratio between two frequencies is simple we hear the interval as consonant—good sounding. When the interval is complicated it generally sounds dissonant. The premise for music is, as far as I'm aware, common to all cultures that have developed music. What isn't common to all cultures is the degree to which we allow the ratios to get complicated. The simplest ratio is 2:1, the octave. Add in some ratios like 3:2 or 4:3 and you get intervals like the \"perfect fifth\" and \"perfect fourth\". These intervals are very common in different cultures' music. For the pentatonic scale you stop adding new notes pretty soon. For the Western scale you keep going until you have 13 mostly evenly-spaced notes (including the octave), then a mathematician comes in and \"fixes\" it so that the notes are exactly evenly spaced. For some middle eastern music you keep going and add in more notes inbetween the 13 notes of Western music. A person from any of these cultures would find music with their own scale to sound good, music from a simpler scale to sound good (though perhaps bland), and music from a more complicated scale to sound positively dissonant (aside: I'm not a fan of the Middle Eastern music I listened to in a class on the topic in college). By using the pentatonic scale the presenter in the video has tapped into the lowest common denominator. If a culture has music then those 5 notes and the intervals between them have probably been accepted and are probably considered to sound like music, not like nails on a chalkboard. The presenter has to spoon feed a ton of information about what he wants out of the audience, but at *some* point the musically inclined in the audience will pick up on it and will carry the rest of the people. He talks about an ability to do that routine \"anywhere,\" but I wouldn't be at all surprised if it would fail if done in a culture that does not have music. That's a difficult test to do, though.",
"I looked at the video and he was using two techniques that are skewing the statistics. Firstly, the cultural learning of the western 'scales' used in our music. Visit India and the population has a very different interpretation of what is a 'natural scale'. Secondly, he pre-loaded us with the expected 'gap' between notes by teaching us where the second note was supposed to be. The third note could only ever be where we interpreted it to be... in relation to the previous two."
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5wt455 | Why are saltwater aquariums so hard to maintain, but the fish can live in the ocean with a lot more variables? | Biology | explainlikeimfive | {
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"It's largely *because* there are so many variables that are typically present in the ocean, but not in an aquarium. There are a million different chemicals that are present in the ocean in specific concentrations that won't be present in the aquarium, often because we don't know which of them is important or not. Even when they're not directly related to fish health, simply *changing* that environment is stressful. Reefs, mostly, don't change. They haven't changed significantly in tens of thousands of years\\*. Because of that, marine life isn't accustomed to dealing with changes. They're also part of hugely complex web of resources - every fish on the reef has a specialized diet. You can replicate that diet, but only to a degree. For instance, most marine angels eat corals, which is undesirable in an aquarium because corals are *expensive*. On the reef, the angel could graze from place to place, eating a few polyps on a colony of thousands and move onto another colony while the first recovers - in an aquarium, there's only so many corals to munch on so they're all going to get munched on all the time. Ok, so don't keep angels with corals. Except that some angels are obligate corallivores - their diet *must* include coral. Tangs, like [blue regal tangs]( URL_1 ), eat algae, specifically macroalgae (seaweed), which means you *have* to include seaweed in their diet. Except your angels, even if they don't need coral, still want meaty foods. So you have to feed two different things. Puffer fish have a fused tooth like a beak, which they use to scrape meat out of shells - they eat clams and snails. If their diet does not include clams and snails, their beak doesn't get worn down and, just like a rabbit, it will continue to grow until it hurts them. Every single fish in your aquarium will have a specialized diet, and often we don't know what all is in that diet. Not to mention the rest of the food web, from phytoplankton, zooplankton, diatoms, copepods, amphipods... Some foods may not be available in your tank without feeding *those*, and so on. All of that assumes your fish will eat prepared foods *at all*. Except for *basically* most clownfish, seahorses, and a very, *very* small group of other fish, literally every other saltwater fish you see in an aquarium was wild caught. All of them. You may be offering them a high quality food pellet with every nutrient they need to survive, but they may never recognize that as food. It doesn't *look* like food to them, because even if it's made of shrimp and seaweed, it doesn't look like shrimp and seaweed. Some saltwater fish are very picky eaters and will never take to prepared foods, like [seahorses]( URL_4 ) (that's my tank!). They will *only* eat live food, or frozen food like thawed mysis shrimp, even if they're captive bred! The ocean is also big enough to absorb problems. Consider the [nitrogen cycle]( URL_0 ): fish produce ammonia during their metabolic processes, which is broken down by bacteria, then broken down again until it becomes nitrate. In nature, that nitrate is absorbed by plants for the nitrogren, converted back, eat by the fish, converted into ammonia...etc. In your aquarium, you are always adding nitrogen via the food, but it's not *going* anywhere. Once it enters your tank, it stays there until you remove it. In the ocean, that's millions of gallons of water to absorb and spread out the nitrate while the plants absorb it, plus there's tons of plankton also absorbing it, *plus* there's tons of surface area for the nitrogen to evaporate into the air. None of that exists for your aquarium, so nitrate can build up very quickly. The same applies to things that mess with your pH (which has to be very consistent at 8.3 to 8.4) - the pH of the ocean doesn't change\\*, it's too big, but your teeny tiny tank may see pretty big swings in pH, or salinity, or temperature, which the fish are not equipped to deal with. There are so many factors to keep track of in your aquarium and not a whole lot of time to do it before it's changed enough to be stressful for the fish. There's also the problem of space: even small reef fish that pick one hole and live there, or one small territory are used to a *lot* of space around them. Nomadic fish like tangs are used to having huge amounts of room to swim through. Being stuck in a small tank can be very stressful, especially if you make the mistake of overcrowding your tank or not having an appropriately sized tank (adult tangs need tanks in the hundreds of gallons to feel comfortable). Along with space, they're used to having features to hide in or hide around, and having big open spaces with no rocks or corals can make them feel unsafe. *They* don't know there aren't any sharks around, so they're looking for a place to hide, just in case, and there aren't any. Which often leaves you with a catch 22: less rock so your fish have more room to swim, but no place to hide, or places to hide but no room to swim. Finding that balance can be difficult. There's more I could go into, like compatibility (which fish will eat each other or fight each other), how stressful transportation is, some of the questionable methods used to catch aquarium fish (like using cyanide - yes it's exactly as dangerous as it sounds, for both the fish and the diver), the deplorable conditions some of them are kept in before they make it to your tank...some of the absolutely, hideously deplorable conditions people try to keep them in at home...believe it or not, even saltwater fish are hardier than people give them credit for, you just would not believe how many people do it *wrong*, and how pants-on-head stupidly wrong they do it (\"I just set my 10g up yesterday, the ammonia is reading at 4ppm, the pH is at 7.2, and the salinity is at 1.030...can I get three blue tangs, four clownfish, two angelfish, eight damsels, an eel, and a puffer? Thanks...\"). (Seriously, if you want to set up an aquarium, fresh or salt, awesome! Go to /r/Aquariums and ask questions, or just PM me, aquariums are literally my job; I'm more than happy to help! Do your research, do it right, be patient, and take care of the animals you're bringing into your home.) *Global climate change is having an effect: see [ocean acidification]( URL_2 ). Along with rising temperatures and changes to salinity, the effects are [not good]( URL_3 ). Marine life is having a really tough time dealing with the changes going on in their environments for many of the same reasons they have trouble dealing with aquariums. Their ecosystems have evolved a very delicate balance, and they all fit very carefully inside that balance, so when one thing gets out of whack the whole reef suffers.",
"Because fish have evolved to live in the conditions of the ocean, and these conditions hardly fluctuate. Consider the amount of water and ions used by a single fish. Now consider this amount to the size of the ocean. Even though the ocean has more than one fish (duh) most fish don't change their environmental conditions enough to displace the effect of how big the ocean is and so their local environment keeps very similar conditions all year. TL;DR: the conditions in the ocean don't change very much but aquarium conditions do, due to the size difference"
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"https://www.pmel.noaa.gov/co2/story/What+is+Ocean+Acidification%3F",
"http://www.bbc.com/news/world-australia-38127320",
"http://imgur.com/a/tLSeU"
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5wtdwd | Math Variables. | Letters / symbols are recycled across different disciplines and their formulas. Is there a constant relationship I'm missing? Eg: For the most part, I think Lamda is used as a frequency or a rate value of some type. Lamda is one wavelength of electromagnetic radiation but it is also the latent heat of fusion and linear density. [k] is a spring constant and [k] is also the coefficient of thermal conductivity. Or were these symbols / letters chosen at random to represent constants and/or variables? | Mathematics | explainlikeimfive | {
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"There are general trends, but no absolute rules. λ is used for ~~frequency~~ wavelength in physics, but it also used for the completely unrelated λ calculus in computer science. k is used for a variety of constants, as is C. i use commonly used for indices, but it is also the imaginary constant. n can be an exponent, the dimensions of a matrix, or the number of compoundings per year in accounting. The reality is there is need for more than 26 different variables. Or 52. Or 76 or 100 when you add the Greek letters. Some letters are going to have to be duplicated.",
"The thing is, there is a limited set of symbols to use. In general, we use the western alphabet, plus the Greek alphabet. Even if you consider all the uppercase and lowercase versions of both of those, it's still a limited set of variables. That means that symbols end up getting reused. Sometimes they get reused in ways that make sense, sometimes they don't. You just have to know what area of math or science you are working with and what symbols are likely to mean in that particular situation."
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5wtki7 | How do diet drinks have zero calories? | Chemistry | explainlikeimfive | {
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"text": [
"Zero calorie drinks typically have extremely strong sweeteners that can taste just as sweet as sugar with less than a hundredth as much of the compound by weight. Most of what is in a zero calorie drink is just water. The tiny amounts of other compounds add up to less than 1 calorie per serve, and so the drinks can be legally marketed as having 0 calories."
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5wtlkc | If humans were to see in the inferred spectrum, how would that effect our vision? | Biology | explainlikeimfive | {
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"text": [
"You would perceive that information in a translated way. Remember, what you see is not what's in front of your eyes. It's information that was collected by your eyes, signaled to your brain, and then, your brain makes the \"image\". An ability to see in infrared would add more information to that picture, but that could be expressed in a lot of ways. (Which are hard to imagine by us, because we can't see infrared). It's the problem of dimensions. If space was 4D instead of 3D, what would you see?..(We have no f\"$%in idea. xD)"
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5wtmd4 | Why is the smell foul when things decompose?Why isn't it pleasant? | Chemistry | explainlikeimfive | {
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"Thinking about it logically, I would have to assume this is more biological instead of chemical (yes, there are chemical reactions taking place, but they are subsequent to biological processes). I don't know exactly what happens chemically, but I think that our bodies have evolved to find the smell of decomposition repulsive so as not to indulge in it. It's the same with other animals. Obviously humans have natural predators. No animal wants to eat a decaying body, because it's filled with bacteria and other harmful things. But an animal can't tell the difference between sleeping and dead, so the \"smell\" that comes off of decaying animals indicates to them that they are already dead and decomposing, and are not to be consumed. Back in our Hunter-gatherer days, this was a useful adaptation, so that we didn't consume things that were decaying and bad for us. Our bodies naturally evolved to find the smell of bacterial decomposition repulsive and unappetizing. Does this make sense?",
"Generally, things smell bad when they have [amine groups and thiols]( URL_0 ). Amine groups are nitrogens with some hydrogens around them, and thiols are sulfur with some hydrogen. Your nose has evolved specifically to pick these things out as \"fucking gross.\" The reason we evolved to pick those out is because when something is rotting, a lot of amines and some thiols get produced by the bacteria, fungus, and insects picking over the rotten material. If you eat something that's in the process of rotting, you're probably going to get sick, and in a pre-medical society like what we evolved in, that could easily kill you if not weaken you enough that something else kills you. Also, shit has a lot of those things in there, and it's also riddled with bacteria, viruses, and parasites in pre-medical societies: you don't want to be messing around with shit if you have no chance of medical care. Your brain is pretty much hardwired to generate a strong response whenever your nose detects those chemical groups, and it's doing it to keep you from getting sick. Speaking of getting sick, the reason people often throw up when exposed to these smells is very similar. If you're eating something you just found on the ground (you're a caveman, and you give no fucks about ground food), and suddenly smell that on the food, you throw up because that purges your stomach. It's a last-ditch effort to keep you from catching a disease. Same goes for just smelling something foul while eating: cross contamination could have happened). This is, of course, an educated guess because we can never know the exact reasons our body evolved the way it did. What it *is* is a very probable explanation."
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5wtmoe | What happens in our brains when we get sleepy from doing something boring to us versus doing something interesting that will keep us awake for several more hours? | Biology | explainlikeimfive | {
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"Directed attention fatigue (DAF) is a neurological phenomenon that results from overuse of the brain’s inhibitory attention mechanisms, which handle incoming distractions while maintaining focus on a specific task. The greatest threat to a given focus of attention is competition from other stimuli that can cause a shift in focus. This is because one maintains focus on a particular thought by inhibiting all potential distractions and not by strengthening that central mental activity. Directed attention fatigue occurs when a particular part of the brain’s global inhibitory system is overworked due to the suppression of increasing numbers of stimuli. This temporary condition is not a clinical illness or a personality disorder. It is rather a temporary fatigue of the inhibitory mechanisms in the brain. Essentially, you're working your brain more when you're trying to focus on something boring while on the other hand the job wouldn't be as hard if you were doing something interesting. Because of that mental exertion, you may feel sleepier and more exhausted. Signs of Directed Attention Fatigue include temporarily feeling unusually distractible, impatient, forgetful, or cranky when there is no associated illness. In more severe forms, it can lead to bad judgment, apathy, or accidents, and can contribute to increased stress levels."
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5wty07 | What do they do if someone pulls the fire alarm in a hospital when they're in the middle of a major surgery (open-heart bypass or something)? | Other | explainlikeimfive | {
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"Many hospitals have their fire alarms set up in zones. So each wing/floor/area is its own zone. When the fire alarm is activated in a zone, either from a pull station or a detector, the audible alarm will only sound in the affected zone. It will also close all the fire doors in the area, which are held open by magnets. The fire department receives the activation and responds while hospital security will go to investigate if there is a fire. Hospital staff or the fire department can expand the activated areas as needed, and usually the rest hospital will be notified of a fire alarm somewhere in the hospital by an announcement for a \"Code Red.\" along with the area of the hospital that is affected. Because of this set up, its unlikely the surgical procedure would be impacted at all. Even if the activation was in the same zone, they would most likely continue as long as no flames or smoke were seen. This may not be the set up in all hospitals, but has been in the ones I have worked with. Source: am former fire prevention officer. EDIT: Spelling",
"Surgeon here, from UK. Excellent question! And one that I didn't know the answer to until actually went through it! I previously worked in a hospital in London when there was a large fire within the building, in the basement. Although there was no fire actually within the operating theatres, it affected the ventilation system and smoke was entering the ORs. The Clinical lead (head doctor of the hospital) informed all theatres that all operating to cease ASAP. What ended up happening was: Those that were almost finished hurried up, those that had just started stopped, those that were literally half-way through just covered up as best they could (made it as a safe as possible, cover the wound etc) and the still-anaesthetised patient was wheeled to a \"pop-up\" ITU somewhere safe & away from the smoke. As it happened the fire was quickly brought under control, ventilation system was disabled and the few (1 or 2) patients that needed it went back to theatre the next day I think. Although less than ideal patients can be kept anaesthetised for quite a while and could even be transferred to other hospitals if required (which is what I'd imagine you'd have to do if someone was actually on CPB (cardio-pulmonary bypass). Would be a massive pain in the arse logistically, but when there's a need these things get sorted. There wasn't any cardiac at this hospital so that particular scenario wasn't encountered... Hope that helps!",
"Everyone in the hospital is taught race and pass before you even get to your station. Hospitals are built to compartmentalized fires so race: R = Recuse & remove anyone from immediate danger A = activate alarm C = Contain - close the doors, most systems do this for you these days E = extinguish small fires or evacuate if in harms way P = Pull A = Aim S = Squeeze S = Sweep You do not evacuate a hospital because a fire alarm is triggered. It is common to be triggered because of the lab and other departments. Like a high rise in a major city, unless immediate damaged presents itself you wait for instruction before evacuating. The only difference between a hospital and any other building is the design to compartmentalized the fire and not allow it to spread. Other buildings besides hospitals are erected this way but not your standard house or high rise due to cost. You could ask what happens during surgery and a power outage. The simple answer is very expensive generators with flkywheels. You won't even see a blip in the lights.",
"I've been in an operating theatre when the fire alarm went off - a naked acutely psychotic man was crawling through the ceilings of the hospital, setting things on fire. Seriously. False alarms go off quite often, so nobody panicked, just rolled their eyes. But smoke started seeping in under the theatre door so then we knew it was real. We were doing abdominal surgery on a 1 year old child. Very calmly, the surgeon and anaesthetist stated that if the smoke became stronger they expected all the other theatre staff to leave, and they would stay until they were overwhelmed. Luckily the smoke didn't become stronger..... we didn't have to find out at what point the surgeon and anaesthetist would abandon their patient.",
"Where I'm on placement, hospitals are designed with this in mind using a concept called compartmentalisation. Each ward/section/area is a different 'compartment' separated by fire resistant walls and separated by fire doors with an estimated time of 60 minutes (i.e. They are theoretically able to withstand a direct flame for a total of 60 minutes). This both buys time for moving patients and limits damage caused in the event of a fire. Therefore, throughout the hospital there are two fire alarm types: 1) Continuous: the compartment you are currently in contains a fire. In this event, if it is not a false alarm, measures may need to be taken in order to stabilise and move the patient into another compartment, in order to continue the surgery there. 2) Intermittent: a compartment adjacent to the one you are currently in contains the fire. I imagine in this case, the surgeons would attempt to continue with the operation in the assumption that they are not under any immediate threat, as in theory even in the event of a serious fire, their compartment will not be at risk for another 60 minutes, in which time emergency services will notify them of the very real danger.",
"Actually, this question has been asked before, at least on /r/NoStupidQuestions/. Here's a link for the replies on that thread: URL_0 The top answer on that thread was \"They keep working, have people prepare to move/stabilize patient if necessary and monitor the situation till it's certain they have to leave.\".",
"We had a fire in theatre one day (someone put something flammable in a warming cupboard) and all the other theatres kept operating. We were just kept up to date with what was going on next door. We did have training drills if we had to evacuate mid operation, and the plan was to stabilise the patient, cover any open wounds and prepare for transport. The destination would be an empty theatre out of the fire zone or a nearby hospital. Transfer to another hospital would be by intensive care ambulance as the patient would still be under anaesthetic.",
"When in HS I was having surgery for an abdominal hernia and someone called a bomb threat into the surgical clinic just as they opened me up. I guess the surgeon and the anesthesiologist both stayed to finish as everyone else was evacuated from the building. I started coming out of it while being loaded into or out of an ambulance and being taken to a different hospital to recover. I remember thinking, \"this can't be a good sign\" then passing back out.",
"I know I shouldn't do this, but I ignore nearly everything I hear over the intercom at the hospitals I work. You hear alarms a lot and you get numb to them. So I'd keep operating and wouldn't notice it until I saw an actual fire or a lot of smoke.",
"Surg tech student here, yes it's all zoned, and inside an OR you can almost NEVER hear what's outside. It's really well isolates that even if the fire alarm in zone a sounded and you're in the OR (zone b) you couldn't possible hear it. Then there's certainly protocols, you keep doing the surgery till you must evacuate, usually the RN will keep up with the fire info and let the surgeon know if it's serious and they have to evac. Typically if it's just an alarm the hospitals are high tech enough to know if it's because of a fire or what not. Usually no one pulls the fire alarm for shits and giggles, even if there is a fire I wouldn't pull it, I'll grab the fire extinguisher and PASS (pull aim spray sweep) and god help me. If there was a massive fire in the OR(let's say an anesthetic gas exploded in the neighboring OR, it can be put out by either fire extinguisher or by negative pressure, all OR rooms have positive pressure, where the air is filtered and pushed into the or is if the door is opened it pushes the bad outside air, away from the room. You can easily reverse this in the control system and suck all the air out and choke the flame that way. On top of that everything used now a days is fire retardant, resistant, and non flame able. (And this is in the actual OR, so worst case scenario). Then if nothing can be done to stop the fire, you have to move to any neighboring core/floor/unit and finish the procedure plus my job is to keep all the equipment sterile so yeah...That's not happening even if I tried.",
"I was assisting in surgery and this happened. We kept going, but man that alarm was annoying.",
"Some interesting Googling to be had here... Among numerous [reports]( URL_2 ) about a Japanese woman farting and causing a fire during her surgery, is an [article]( URL_1 ) saying \"*Virtually all operating room fires ignite on or in the patient, and about 10 surgical patient fires a year come to ECRI's attention*\". And a specific [case study]( URL_0 ) about such an incident.",
"Why does it say there are three comments and then down where the comments are supposed to be, it says \"there doesn't seem to be anything here\"? Is Reddit broken?",
"I was walking in a hospital hallway when the fire alarm went off once. These large doors closed behind and in front of us so it divided the hallway into segments. Imagine that one red laser door part of Phantom Menace, but with a group of people and a bigger compartment.",
"Due to the nature of a hospital, it is not always possible to evacuate the entire building in the event of a fire and are designed with this in mind. Walls, floors and celing are designed to slow down the spread of fire and doors are rated as being 30, 45 or even 60 minutes fire proof (next time you are in a hospital look out for tags on door displaying such a number). These doors also have expandable interiors (the 1cm wide white strips in the center of the door) which once heated, create a air tight seal. In the event of a fire, patients are moved from the immediate area into adjoining wards and so forth until the fire is extinguished. Should a patient be on the operating table when a fire starts in the next room, the surges would have sufficient time to stabalise the patient and move them further away from the fire before the operation can be sucessfully completed or brought to a satisfactory conclusion. Baring in mind the fire service can be at the scene within 20 minutes of discovery of the fire, moving the patient to literally the next room could give the fire service 100 minutes to extinguish a contained fire.",
"In my hospital we have different codes (announced over the PA) for different kinds of emergency. A code red is a potential fire in an area - staff will search for the fire and the fire dept will be notified to attend and assist. A code orange is an evacuation notice - all staff have to leave and arrange for the Pt to be evacuated too. I'm not actually sure what happens in my hospital when it comes to a code orange in theatres - id hope we have a procedure in place! In the case of open heart surgery for the most part a patient is on a heart lung machine. The cannulae used for heart lung machines can be easily incorporated into a device called ECMO which is a longer lasting heart lung machine that can provide full replacement for a pts heart and or lungs for days (and up to weeks). ECMO Is easily mobile and allows a Pt to be moved from one area to another safely. We also actually leave pts chests open occasionally. A simple piece of plastic is all that is put over the pts chest and it's left open for a few days. This is done infrequently when the swelling in the thorax is so significant that the sternum can't be safely closed. Source: Clinical Nurse Specialist in Cardiothoracic ICU and ECMO operator. Edit: there are some absolute excellent answers on how to evacuate and manage fires in hospital! It's not my area of expertise - I was mainly looking to provide clarification on the 'open heart bypass' part."
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5wuo1c | Why do flies and other flying insects not have the reaction to fly away when a huge hand is swatting them away constantly? | Biology | explainlikeimfive | {
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"Insects do not have a brain. All their actions are based on a complex set of reflexes to various of events. Being swatted away is unlikely to be something they are even capable of remembering."
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5wurcy | Movie scripts - how detailed they have to be - and what would be considered overkill? How much freedom they give or allow for the director? How can one director make a better movie than other from the same script? | I know it sounds like 3 questions, but i think they all revolve around the same idea | Other | explainlikeimfive | {
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"Having read many scripts now I'd say the answer is it varies enormously - some scripts are detailed [exit, pursued by bear] while others offer little beyond the dialogue. The text from many scripts is now available for free online, there are even [facsimile copies]( URL_0 ) of some of the originals so you can see how it was all formatted. There are huge differences between scripts, and the amount of detail offered. If you haven't, consider searching for the scripts of a couple of your favourite films, with which you are very familiar, and read the scripts for those. This can be very interesting, and rewarding if you want to learn about script writing. A director can interpret a script in an infinite number of ways. Some invent approaches that have never been used before, and some develop a signature style that is theirs and theirs alone. The film industry has a short history, relatively, and it is a history of innovation. For example, in 'Citizen Kane' Orson Wells has a character lie on a bed, not moving. On the bedside table is a small bottle of prescription medicine. This situation is simple, though dramatic. How would you direct this scene? Would you make it short, or long? Would you film it in close-up, or from a distance, from the window outside looking inside, from the hallway, is the room dark or light, what is the character wearing? What music would you use to accompany this scene, or would there be some other kind of soundtrack, such as a banal telephone conversation of people oblivious to the tragedy, or will you hint at the next scene by starting the soundtrack to that early? There are so many questions a director answers for each scene. Wells in his interpretation of this scenario makes use of dramatic lighting, and shows the room from an extreme angle from near the bedside table, with both the medicine bottle and Kane, who bursts into the room, in focus. The anecdote I heard is that at the time this caused the industry media to headline this scene, as camera operators and technicians tried to work out how Wells had managed the deep focus. It was assumed by many he had invented a new kind of camera. What I heard is that Wells had the properties' professionals build a massive and irregular shaped bedside cupboard and medicine bottle, built to deliver a visual illusion that the camera was next to a normal shaped bedside piece of furniture, yet still keeping both Kane and the medicine bottle in focus. Edit: got mixed up between Kane and poor Susan.",
"You might enjoy this [shot]( URL_0 ) also. In Scorsese's film 'Goodfellas' he has a scene where Henry, the young gangster, takes out Karen for a date. In the acclaimed and famous scene the couple enter a nightclub together. Again, a simple scenario. Scorsese uses the scene to reveal much about Henry's character to Karen, and about them both to the audience. The bravado of Henry's in part seduces Karen. But what a shot! Think of all the organisation required to get this shot - it is so long and involves so many people! At the time such steadicam work was near experimental."
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5wut2s | How does consistently getting very few hours of sleep reduce your life expectancy? | I saw something about this the other day but nothing was said as to what actually happens. Might be false but I thought it was interesting. | Biology | explainlikeimfive | {
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"A [review of studies]( URL_2 ) found that those averaging less than 6 hours of sleep per night had a 12% greater chance of premature death. The amount of sleep gained is probably not likely to directly affect life expectancy. Instead, [poorer sleep is likely to be a general indicator of poor health, rather than a cause of it.]( URL_0 ) Thus, those with abnormal sleeping patterns/quantities are more likely to have medical or mental health conditions causing this abnormal sleep (this also applies to those who get too much sleep- more than 9 hours), many of which are associated with an increased morbidity and mortality, and also lower socioeconomic class, and thus poorer access to good healthcare, in keeping with the [inverse care law. ]( URL_1 )"
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5wutag | Why does staying in bed after I wake up make me more tired? | Biology | explainlikeimfive | {
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"Everybody has an internal body clock called a [circadian rhythm]( URL_3 ). Without going into too much detail, this is a 24-hour cycle of hormone levels, which have an effect on all organs, including the brain. This results in what is known as a person's [chronotype]( URL_4 ), which is defined as a description of the preference or inclination to sleep at different times of the day, as well as the times during which a person is most energetic - this is where the terms \"early bird\" and \"night owl\" come from, they are merely descriptions of different chronotypes. (The circadian rhythm is also why some mental health conditions such as depression exhibit a phenomenon called \"diurnal variation\", whereby symptoms become more apparent at certain times of the 24-hour clock). The circadian rhythm (and thus the hormones such as melatonin and cortisol which are released in time with it) is all controlled by neural networks within the [suprachiasmatic nucleus]( URL_0 ) in the hypothalamus of the brain. Uniquely within this brain region, a cascade of genes (such as the [CLOCK ]( URL_1 ) gene) negatively feedback each other in a sort of loop, which lasts roughly 24 hours, which is what gives the circadian rhythm its regular cycle. This rhythm is all calibrated by a process called [photoperiodism]( URL_2 ), whereby photons near to the blue wavelengths (such as those from the sun) 'calibrate' the cycle, to ensure that your chronotype is tuned to make you feel tired during the night and active during the day (this is why many phones such as the iPhone now have a 'night shift' mode to reduce the amount of blue light emitted, to reduce the bad effects of screen time on sleep quality). The whole circadian rhythm can, therefore, be put out of calibration by excessive lye-ins, particularly when the room is darkened, due to the absence of input from the process of photoperiodism, and thus depriving the suprachiasmatic nucleus of the all important reset it needs. Futhermore, people are usually tuned to wake up after about 5 sleep cycles (the sequential stages of varying brain activity which occurs during healthy, normal sleep), and usually wake up at a particular point during a sleep cycle (this is the basis of many special alarm clock apps which are designed to wake you up at the best time in your sleep cycle). These 5 cycles together last about 7-8 hours, making this the optimal sleeping time. If you surpass this, you may extend the number of sleep cycles, and wake up in a less favourable part of the subsequent cycle, making you feel more groggy when you wake. Hope this helps. Edit: some grammar"
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5wuthj | Why are giants depicted as being far slower than normal sized people in films? | Physics | explainlikeimfive | {
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"They are actually faster, but just *seem* slower. When a giant takes a step, it looks like it is in slow motion for us if we were to mimic that exact movement at our scale, but the giant actually moves *much* faster than us to get one foot from one spot to another spot way further away. They can't move their limbs as fast as we can *relatively* because they travel far more distance whenever they do move in that way. You might flap your hand really rapidly, and it might move at some certain speed to get from one position to the next, but a giant has to move their hand *so* much faster to get from that position to the next that there's no way it has the strength or power to move that speed. It would be like you trying to flap your arms as fast as a bumblebee's wings."
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5wuux8 | How do different eyesight problems differ to each other? i.e. long sighted, short sighted, astigmatism | I have an astigmatism and often see the pictures at the optometrist showing a diagram of an eye affected by each eyesight problem, the explanations never make much sense about oval eyes or long eyes vs. rounded eyes, what causes these problems? How does an astigmatism differ to being near sighted? | Biology | explainlikeimfive | {
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"To see, light has to hit our eye, and then reflect back onto the retina. This image is then sent to our brain and then comprehended. If you are short-sighted, the eyeball is either curved wrong, or too long, and instead of hitting the retina directly, the light goes in front of the retina, causing you to not be able to see things far away. Long-sighted is the opposite, with a too-short eyeball causing light to go behind the retina. This means you can focus on things far away, but not too close. Astigmatism is something else entirely. It just means that your cornea or lens ( the visible,curved, clear part of your eye) isn't smooth. This means the light rays again aren't refracted properly. You can have astimgatism and be near-sighted ( I am!) it's just a double whammy of not refracting the light properly."
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5wuwpd | do caterpillars know they will become butterflies or just wrap into a cocoon thinking "wtf am i doing?" | Biology | explainlikeimfive | {
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"I'm pretty sure it's based on a certain hormone, and when the hormone level is low, the caterpillar is biologically driven to create a chrysalis and enter it. Caterpillars don't have the capacity to \"know\" things. Their behaviors are driven by instinct, biological processes, and environmental factors.",
"Do newborn humans know they will grow up to be an adult, walk and respond on Reddit? That is what nature is, an evolution of order based on specific species and individuals that involve things the entity has no control over and are destined to do. Some would call that instinct.",
"When they taught apes sign language they realized something interesting: the apes never asked a question. They could communicate information \"I like you. I like banananas\" But they couldn't say \"Goodnight, when do you come back tomorrow?\" or \"Why am I here?\"",
"Not a scientist, but it seems to me that 'knowing' is probably the wrong term to use when talking about caterpillars. I mean, it probably 'knows' what it's doing in terms of it being compelled to do it and 'knowing' that it's the thing to do. But its not like it forms the thought \"When I wrap myself into this cocoon I will turn myself into soup. Then after a few days I will burst out and learn how to fly so that I can reproduce and die.\"",
"Pretty much the latter, but without the thinking part. It's pure instinct. Caterpillars don't have sentience and can't \"think\" anything."
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5wuyo2 | My first language is Vietnamese, second language English, my sister is the same as me, and we are able to switch between languages mid sentence and they would make perfect sense to us, both grammatically and syntactically; how is this possible ? | Other | explainlikeimfive | {
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"It's called code switching. It's very common among people raised speaking multiple languages. It comes from the fact that languages learned before the age of 12 (or so) are much more deeply ingrained than those learned later in life and your brain can seamlessly switch between them mid-sentence or even mid-phrase. There's several hypotheses about why this happens and which hypothesis best fits varies depending on the languages involved. I don't know enough about Vietnamese to guess which one applies."
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5wv5sy | What would happen if the speed of light were only one mile per hour? | Physics | explainlikeimfive | {
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"First things first, I greatly recommend trying a \"game\" [Slower speed of light]( URL_0 ) by some folk on MIT that simulates these effects. And my answer: Our solar system as we know it could not exist under such conditions. The Earth alone rotates with surface speeds much higher than that (~~733 MPH~~ 1037 MPH at equator), and the entire Earth moves much faster than that around our sun. Air that you breathe and blood in your veins also moves faster and you couldn't function because of physics. But leaving that aside, if we somehow had current conditions and the speed of light slowed down this much, your experience of the world would be extremely bizarre. For example, if you move relative to your surroundings, you see things in front of you blue-shifted while things in the back are red shifted. So light you see literally changes color based on your movement. Normally, you move at an infinitesimal fraction of speed of light, so you can't possibly detect this. But if speed of light would be that low, moving even a 0.75 mph would shift the wavelengths extremely, way past visible light. Another thing is, that your surroundings would appear to change geometry based on your speed and direction. Under certain conditions, you could literally see front and back sides of objects (such as road signs)."
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5wv6te | What is the neuroscience of meditation/spirituality? | Biology | explainlikeimfive | {
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"Ask this question again in late April/early May, as I'll be taking that as the topic of my term paper in my cognitive neuroscience course. From the little research I've gathered so far, the meditative state has a plethora of activation patterns that differ from other states. One of the major patterns is Transient Hypofrontality, or essentially brief periods of reduced activity/blood-flow to the frontal lobes (involved in many functions such as emotional processing, impulse control, and planning or risk assessment)."
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5wv74h | Why can't humans taste water? | It seems a bit of an arbitrary development. After all, we can easily taste other simple compounds (NaCl for instance) but pure H2O has no discernible taste. Why? | Biology | explainlikeimfive | {
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"What would be the point of having tastebuds that detect H20? Your mouth is *always* full of water. You'd lose your ability to taste it before you were even born due to sensory fatigue.",
"If people could taste water, or better yet, if water had a flavor then there would be people that would claim they didn't like the taste of it. You need water to live, we all need water to live. I understand that there are people out there that say, \"I don't like water.\" What they're really saying is they'd rather have a sugar filled soda instead. But put those same people in a desert for an hour or more, walking around in the hot sun and suddenly their bodies will cry out for it. Just my two pennies.",
"You premise is wrong, humans can taste water. If you did a blind taste test people would be able to accurately identify water."
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5wv9n1 | If one destroy enough money, can one theoretically inflate the worth of each dollar bill? | Economics | explainlikeimfive | {
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"Not materially, no. The actual % of the total 'money' that exists and notes and coins is quite small. At a guess, 5-6%. So even destroying it all, there is still 95% of the value of 'money' that hasn't been removed from the market. I guess if you destroyed enough of them, and the central bank didn't print any more - they'd be collectors items and have more value.",
"Realistically no, however, if you became a multi-trillionaire, had a bank account in every bank in the US, then simultaneously withdrew all your money from each bank, it would cause a temporary depression.",
"I think I see what you're asking. If Bill Gates, Warren Buffet and the Koch Brothers all (gradually for the sake of the argument) liquidated their assets and kept their money out of circulation forever (effectively destroying it), that could affect a 0.26% increase in the value of your money (Given that they have 200 billion and there is 75 trillion in the world). However, this assumes that they spend all of their money on the same things as you do (their demand is scaled and factored into the market) and there is 1 world currency. In realistic conditions, you would have to have a very large amount of money to cause significant deflation and the side effects would put the world in a little bout of chaos.",
"Yes you can! Of course in the most part our assets are in fiat money(money on someones bank account) or in buildings and businesses. But if you destroy enough real bank notes the demand for those banknotes will go up in those areas where you need to exchange cash. Also there is the promise tjat you can exchange your assets against liquid cash. So in short you increase the demand for money and the we inflate the value of each dollâr bill. We call this process **deflation** at no one should want this process to start! Just think about it. Your money will be worth more tomorrow. There is no reason for you to spend it today. The economy will crash, mass unemployement and negative net infrastructure investment are just some of the results.",
"Well, the paper isn't actually worth anything other than as a collector's item. It's a bank note saying it's worth X-amount of gold or silver but it's actually valueless. Even if you had a genie and wished for all paper money to disappear, technically the money would still be there. (Or it would if we weren't under a huge debt.) What might go up in value is the rarity of the bills. Think about some pristine ancient Roman coin that is the only like it still in existence. It's worth a certain amount based on the materials it's made from, but it's real value comes from it's age and rarity. So if you had the last $20 bill of all time it would be worth more than $20 from a collector's point of view at least."
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5wvb44 | Why are INDOOR pools closed when it storms? | Other | explainlikeimfive | {
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"My pool I supervise at has the water tank and filtration system underground. It can be struck by lightning which would feed into the actual pool and do harm. That's why we evacuate when its lightning outside even though it's indoor.",
"Yes, you are still at risk of being electrocuted when in the pool if lightning strikes close enough. It is the same reason you should avoid showering or taking a bath during a lightning storm.",
"When lighning hits the ground, it has many thousands of amps. That current spreads out in a squashed hemisphere. If it hits near a (very low resistance) copper pipe which runs into the pool, it could spread some of that current through you as it travels out of the pool via another pipe."
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5wviat | Where do we get the chemicals used in laboratories to create medicine? | when I watch videos on internet explaining how stuff works. they just say: we use this chemical, this acid. but I always wonder how do they get that specific stuff? for example, there are chemicals used in aspirin. where do we get those chemicals? do they "boil" a mineral or some plant to get salicylic acid? or how? PS: I used the word "boil" to refer to various chemistry processes. I have no clue how to name them | Chemistry | explainlikeimfive | {
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"While most medicinal chemicals were originally found in plants/animals/whatever natural source was available, modern methods tend not to rely on them. In fact, the majority of modern organic molecules are mass-manufactured from petroleum derivatives. I'll expand a little on your example of salicylic acid: The \"natural\" source of salicylic acid is in *Arabidopsis thaliana*, where it's biosynthesised from phenylalanine, an amino acid. Modern production originates with a molecule called cumene, which is found in crude oil. Cumene gets converted to phenol using a Hock rearrangement. Phenol then gets treated with sodium hydroxide to produce sodium phenolate. Sodium phenolate then gets pressurised with carbon dioxide at a high temperature to make the precursor to salicylic acid. This precursor then gets treated with sulfuric acid to acidify it, making salicylic acid. This might seem like a much more involved process than just extracting it from the plant, but it has the advantages of producing an essentially pure chemical in a predictable manner. tl;dr: Some medical compounds are still extracted from plants, but we've found a way to get most of them from oil."
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5wvx9c | What is the argument against a flat tax in the US? | Economics | explainlikeimfive | {
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"A flat tax places a greater burden upon the less wealthy. This is because there are certain costs which are relatively constant for everyone. For example it might take 30% of a poor person's income to provide food while it certainly doesn't take 30% of Bill Gates's wealth to feed his family. Is Bill's food more expensive than the poor person? Yes, almost certainly, but it doesn't scale at all the same. A flat tax doesn't recognize this changing scale of value compared to total wealth, and would result in either the poor being taxed too heavily or the wealhty being taxed too little.",
"It's not limited to the US - the primary problem with a flat tax is that it shifts the \"pain\" of taxation onto the lower income people. Consider this - The government needs to raise $100 in its country of 10 people. So that would mean that everyone pays $10 and we're good right? Well that is stellar, except that Persons 10-4 make between $12 and $16 leaving them pretty close to impoverished, meanwhile Person 1 makes $100 and has tons left over. That example is pretty simple, but that is kinda the point. Lower income people spend proportionally more of their income on the basic necessities of life. Placing a flat tax on them ignores that there is a limit to how much they can pay before you eat into that. Meanwhile, someone making a ton of money could conceivably pay an enormous tax rate (40, 50 or even higher %) and still come out fine because they are already well beyond the amount of money they need to be comfortable. That is the key benefit of a graduated income system - when properly executed it shifts the burden of taxation onto the people who can afford to pay while pulling very little from the people who can't.",
"Basically, people have income, and disposable income. Disposable income is the money where you actually have the choice of spending it. Its the money you could theoretically dump in the trash bin and you would be fine. Its the money you spend on actually doing stuff you want. Its the money left over after paying rent, utilities, food etcetera. So if i earn 1000$ a month, before i spend a penny, i first pay the 20% flat tax, 800$ left, then i pay rent, 400$ left, then i pay the utilities. 350$ left, then i eat and drink. 150$ left. Now my income has increased tenfold. 10000$, first i pay the flat tax. 8000$ left. Then i pay rent, i moved to a way better apartment, but it sure as hell ain't 4k, its 1.2k. 6800$ left. I pay utilities. 6600. Then i eat, i eat way better now, but i'm not eating 2k worth. 6000$ left. Now to illustrate the problem with flat tax some more, now imagine a 5% tax hike. The poor me goes from 150$ disposable income to 100$, A massive 33% loss of disposable income. Rich me goes from 6000 to 5500$, he loses about 8% of his income.",
"I personally think it could work if the tax rate was low enough for the lowest income, AND everyone paid it. No loopholes for rich people, just a simple if you make X, you pay Y percent of X in taxes.",
"Part of the issue is that there are an enormous number of ways that people make money, some more obvious and some less so. Let's take a simple case: I sell my car for $2000. I originally paid $19000 fot iy. What tax should I pay? * Nothing, on the grounds that a sales tax was already charged? * On the full $2000 because that was the amount I made? * Nothing, on the grounds that I had a capital loss? * On the full $2000 because the car was really only worth $100, but my friends wanted to pay me \"under the table\" for some illegal work? * On part of the $2000 on the grounds that although I had a capital loss, the car had depreciated even more? Can you answer this question in a way that is \"obvious\" and that everyone will agree to? Because all of the above answers seem reasonable. Part of the tax code is to clearly distinguish what needs to have a tax paid. This is needed because otherwise rich people will find the loophole you left in, and suddenly they are paying nothing at all."
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