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6758z1 | how much data video game servers send and receive, and what kind of data is sent and received? | How do the servers for online video games work? How much data is stored on the servers? Basically, in an online game like Overwatch or Call of Duty, what information is sent to and from the servers? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/6758z1/eli5_how_much_data_video_game_servers_send_and/ | {
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"It will vary from game to game and sometimes server to server.\n\nInformation is sent in packets, which are little pieces of data that tell the server something about what the player is doing (x threw a grenade, y interacted with the door, etc.). Usually the server will check to make sure the packets are valid (x has a grenade, y is close enough to the door, etc.) and then sends all the relevant packets back to each of the clients.\n\nA packet can be as simple as [packet id, name, x-coord, y-coord] or as complicated as the game requires. Turn-based games can choose to send packets all at once or continuously (Hearthstone does the latter), but live-action games require continuous packet flow."
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dk24jw | why does citrus fruits divide into boats (how does an orange benefit from it)? does it have anything to do with how they grow/ the nutrition? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/dk24jw/eli5_why_does_citrus_fruits_divide_into_boats_how/ | {
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"Point of clarification: by boats do you mean the wedges/slices once you have removed the peel?",
"Segmentation of fruit like oranges is partially down to how the fruit is fertilised and possibly down to how the fruit is consumed which enables multiple animals to eat it and therefore it could be dispersed in different directions.",
"Apples, and many other fruits have similar structure. It has to do with the flower. Single ovary like plum, peach, etc... or 6 like apple, or multi like citrus.",
"This is just an evolutionary trait to help spread seeds further. Fruits like an avacado have quality over quantity, one big sturdy seed per avocado. Oranges go for the quantity approach. By further segmenting the fruit on top of having multiple seeds per fruit, it increases the probability of seeds traveling farther and taking root.\n\nIt's in a trees best interest to spread its seeds farther away, lest it have competition with its own \"offspring\""
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3je8b8 | the other day i drove by a speed radar sign. the sign was showing a slower speed than my speedometer was showing. which one is more accurate and why? | The radar sign told me I was going 35 while my speedometer was showing 37. To be fair, 2 IS a pretty small margin but I've read elsewhere online that the margin has been even higher for some people. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/3je8b8/eli5_the_other_day_i_drove_by_a_speed_radar_sign/ | {
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"The radar detector is likely to be more accurate. For two reasons:\n\nYour speedometer actually measures rotations of your drive shaft or something directly linked to it, so it presumes that your tires are the same size as those used by the manufacturer to establish the speed, if you've changed brand, tire dimensions, or even potentially inflation pressure it's guaranteed to be off by some amount. Tire size also has an effect on fuel mileage (since it changes the gearing of the engine to road). \n\nSecond, it's likely that the radar detector is owned by the police department and as such is likely to be tested and certified to be admissible in a court (someone who gets a ticket and can show that the certification is out of date will have their ticket voided in court), even if it wasn't being used for tickets at the time. ",
"The sign is probably right. Speedometers are usually calibrated to read slightly high, so that any error in the speedo isn't going to make it show less than your true speed. That way you should never get a speeding ticket even though your speedo said you weren't speeding.",
"Does your speedometer match a GPS or a GPS app on your phone when you are on a straight road?\n\nIf the sign is at an angle to the road, it would somewhat underestimate your speed.\n\nAs u/bulksalty says, if your tires are a little smaller in circumference than the ones that came on the car when it was new, your speed will show higher on the speedometer than your actual speed."
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cyh1uk | if you drive down the road and you roll two back windows down about 30% of the way, it creates a sound that shakes your eardrums. what/how is that happening? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/cyh1uk/eli5_if_you_drive_down_the_road_and_you_roll_two/ | {
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"The British inventor James Dyson would call this phenomenon “buffeting” and markets fans that avoid this choppy movement of air for lots of money.\n\nIf you study the aerodynamics of a vehicle when travelling at speed with the rear windows open, you’ll learn that air instead of diverting round the cabin of the car, it rushes in (like side air intakes of a sports car) but then has nowhere to go, so it fills the cabin with air very quickly and forces out air at a relatively high pressure, hence why you feel this sensation in your ears.",
"Have you ever blown across the top of a soda bottle and made a tone? Have you played a flute or piccolo? That is what is happening, but at a lower frequency or pitch. The frequency or pitch created is called the Helmholtz resonance and is determined by the volume of the air in the car.",
"Have you ever see a big truck driving fast and noticed the sheets along the sides bulging out?\nThe difference in speed between the air inside the truck and the air outside the truck causes this. \nSo the air inside the car is trying to get out already. When you open the window you get more air coming in. This sort of blocks the exit, but once there’s enough air inside the car, it can overcome it briefly and let air out. This on/off between air coming in and out is the noise you’re hearing (buffeting as others have already said).",
"If you blow across the top of an empty bottle, you get a sound - the natural resonance of the volume. The bigger the container, the lower pitch the sound. Same concept as organ pipes or the wind moaning in a canyon. The effect disappears with too big an opening. Apparently 30% is about right for some cars. \n\n(You can prove it's volume related - get a small bottle and a 2-litre bottle. fill the 2 litre with water to the top, then empty enough to fill the small bottle. Do the blowing trick on both. They should have the same note, even though the vertical depth is different.)",
"Think of air as water but because the molecules of air are more spread out it is springy. The car going forward with the front window(s) open is ramming air into the cabin of the car. Because air is springy the pressure bounces back and rushes out the front windows, leaving the cabin in low pressure ready for the cycle to begin. \n \nWhats awesome about this is the car essentially becomes a musical instrument playing a bass frequency, probably 1-30 hertz",
"Toyota venza would do that really bad when the rear windows were all the way down. It sounded like a helicopter was flying above you. Roll the front window down a crack and its silent. \nI always figured it disturbed the air so it wouldnt be smooth to cause the buffeting",
"There is a much simpler answer in my opinion. It's a whistle! Just like when you blow in a common whistle, part of the air goes in the chamber, part out. As the pressure increases then decreases inside the whistle, the frequency of that occurance makes the high pitched whistle noise. The bigger the whistle, the lower the frequency. Make it as big as a car and the frequency drops so low you experience it as a thumping in your eardrums.",
"Full explanation: the car interior is acting as a [Helmholtz resonator](_URL_0_). It's exactly the same as when you blow are across the top of a beer bottle to make a sound.",
"Years back, when my pops had his fabrication company, there was a liquid styrene factory across the street from us. \n\nAfter the epa passed some new regs requiring a vapor recovery system, they installed a huge vapor burnoff stack at the final stage of the system.\n\n Imagine a 36\" to 48\" pipe that stood 60 ft tall with a big flanged outlet on top. For 6 to 10 months, they had hell getting the thing tuned well enough to burn off the vapors and fumes without creating an audible *buffeting* in the area.\n\nThis fucking thing would get so powerful that at 400 to 500 yards away you could stand still and see you shirt tails buffeting in tune....[kinda like the girls hair sitting in the door of one of those competition audio trucks.](_URL_1_)\n\nWe made a number of calls to them to try and get something done, and every time the receptionist would say \" we're trying\" apparently the engineer didn't account for the [combustion of the vapors.](_URL_0_) creating a resonance, similar to the effect in the video",
"Supplementary query, captain: is this effect related to the concept of a \"beat frequency?\"",
"I’m an automotive engineer that designed the roof system in the Bentley Continental.\n\nI had the task dropped on me late in the day, and it’s wasn’t my speciality, so I had to pick up the subject on the run.\n\nIn the automotive industry this is called “Helicoptering” and in an ELI5 description, it’s air that had been pushed upwards by the car, trying to get back in, via the sunroof (works the same with any aperture on a car).\n\nSo the air rushes into the car under quite high pressure, if the car had enough velocity, and pressure builds up inside the car. It builds up quite high, and actually pushes back out of the sunroof and this creates a slight vacuum. Repeat this and you get a cycle of compression and decompression within the car (and sore eardrums unless you open your mouth)\n\nThere are several ways to combat this cycle.\n\n1.\tIgnore it, or open a window.\n\n2.\tBuild [castellations or a mesh](_URL_0_ on the sunroof leading edge (Mercedes, VW group, Kia). \n\n3.\tCreate a vent between the cabin and the outside, so that the air pressure can equalise. (Bentley, JLR). \n\n4.\tReduce how far the sunroof can open, and position the sunroof as far forward as possible (GM). \n\nI’ve put car names to each, but that’s a few years out of date now. Sunroof suppliers will be offering these features to various OEMs.\n\nThe castellations/serrations/mesh create what is called dirty air. They break up the smooth air flow and cause it to break up and twist about, and by the time it reforms into smooth air again, it is halfway along the roof and past the sunroof aperture.\nIt’s very effective at stopping the helicoptering, but does create quite a lot of wind noise.\n\nCreating a vent to the outside is easier for some manufacturers than others. Having a large boot/trunk helps, especially if much of it is above the “wading line” which is the height rain/flood water get. It’s not easy to create a vent yet keep the car sealed for aircon/heating etc.\n\nNo. 4 was an early solution when sunroofs were smaller. It takes advantage of a short area of dirty air right behind the windscreen header.\n\nLike I say, this isn’t my speciality. I just had to jump in to solve a problem, then jump out.\n\nEdit: arrrgh, formatting.",
"its usually only one window. to equalise pressure rolle the opposite but front one down. sp if back left is down put the front right down and problem solved.",
"Fast moving air ruses in through the windows which causes a high pressure due to the inertia of the air (moving air does not want to stop). Air is compressible and so the pressure builds up until it stops the incomming air, but actuallly achieves more pressure than needed. This higher pressure air then \"springs\" back to expell the air that has entered the vehicle until the pressure drops enough for more air to enter. Since this process repeats there is an oscillating pressure in the car and an oscillating pressure is what we hear as sound.\n\n & #x200B;\n\nThe effect is proportional to the shape of the car interior and how far down the windows are. \n\n & #x200B;\n\nIf the windows are down too much the car cannot store enough air to \"spring\" back. Likewise if the window is up too much, not enough air can enter to cause a higher pressure from the little intertia. When you get it just right, the entire thing \"resonates\"",
"Always happens when my wife opens her window more than half way while the rest are closed. Gotta crack a rear window to subdue it",
"-\tair rushes in\n-\tIt has no where to go\n-\tit pushes back to the window (either flows out or keeps air from flowing in)\n\nThen the process repeats itself.\n\nThis creates a repeating in/out flow of air where the air pressure in the car is increasing and decreasing at some rate. You can hear the flow of air and you can feel the change in pressure.\n\nIf you open the sunroof, this typically stops.\n\nNext time you do it, screw with the frequency and amplitude by putting you hand in the open window space.",
"How do you roll the rear windows down while you're driving?",
"yasssss thank you for asking this!!! I always wonder. Also, does it hurt my dog's ears?",
"Why are 3/4 of the top answers removed??"
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7a7qux | operation gladio | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/7a7qux/eli5operation_gladio/ | {
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"\"Gladio\" was the code name for the NATO stay-behind operational plan in Italy during the Cold War. It involved intelligence, special forces, and regular army troops from Italy and other NATO members who, in the event of a successful Warsaw Pact invasion, would stay and fight an insurgent/resistance campaign. Other NATO and neutral countries had similar plans.\n\nThere is a lot of speculation about the involvement of various intelligence agencies (most notably the CIA) and the possible involvement of criminal groups. However as the details of the plan(s) are still secret, there is very little reliable information."
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4f786h | how exactly are new surgical procedures, aesthetic or otherwise, implemented? who gets to be the first guinea pig? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4f786h/eli5_how_exactly_are_new_surgical_procedures/ | {
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"Usually new medical techniques/medicines are tested on animals first (if applicable), then they move on to volunteer testing.\n\nIE you're a terminal cancer patient. You're told you're not going to survive with the current technology (or you have some really small chance). However, your doctor goes 'but we have this experimental procedure we could try. We have no idea if it will work but it might and if it does it would be better than current techniques/medicines. Would you like to volunteer?'\n\nOr you've got some disease like Parkinson's that has no real treatment you might be asked to volunteer in a drug trial for a medicine that could help. That is usually (iirc) Phase 3 which means they've done testing to make sure it is at least safe to ingest or try on humans. Phase 3 usually tells them 'alright now does this actually work better than a placebo or not?'\n\nBut yeah basically they rely on volunteers who are at a point where it is 'might as well try it because I can't get any worse really.' For less serious things like acne treatments they usually will offer volunteers a payment in return for their time."
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42v0io | in big cities with air pollution, is the air dirtier at street level or at higher altitudes? | In a city surrounded by factories and clogged with cars there's a smog that hovers over the city day-after-day.
On a calm afternoon person A is sitting on a bench at park in the middle of the city. At the same time, person B is sitting on the balcony of a tall condo building that's 120m in the air.
Does the air that person A is breathing have a significantly different concentration of VOCs, nitrogen oxides, particulate matter, or other pollutants due to the difference in elevation?
Thanks to anybody who can share any informative insights! | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/42v0io/eli5_in_big_cities_with_air_pollution_is_the_air/ | {
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"This: The few studies conducted on vertical gradients of traffic-related airborne pollutants have been conducted in urban Asia. Wu et al. found a significant decrease in ambient PM concentrations as height near major roadways increased from 2 to 79 m [16]. Li et al. also reported a decrease in the concentrations of outdoor PM2.5 and polycyclic aromatic hydrocarbons (PAHs) as the height of residential building, next to a busy road, increased [17]. These findings were supported further by Tao et al. who showed that measured ambient PAH concentrations decreased with heights in winter due to vehicle emissions at ground level and the observed restrained atmospheric conditions [18]. However, most of these studies were limited by either involving only short-term ambient sampling (e.g., over a few days, in one season), or a specific building type (high-rise building near a major roadway). The effect of season on the vertical gradient of traffic-related pollutants still needs to be elucidated in residential outdoor and indoor environments.\n\nFrom here:_URL_0_"
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44rgkl | why can humans digest sugar and vegetable oil, but not petrol? aren't they all carbon chains? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/44rgkl/eli5_why_can_humans_digest_sugar_and_vegetable/ | {
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"Humans *can* break down the stuff in gasoline like iso-octane. However, it also is highly toxic and damages mucous membranes and acts as a mild narcotic. So it's generally not a good idea to eat.",
"They are all hydrocarbon chains (hydrogen, carbon, and oxygen) but they aren't connected in the same way. your body can only break down certain types of molecules in certain configurations.\n\nsugars and fats break down into smaller sugars and component fatty acids - all of which the body is prepared to digest. the stuff in your gut breaks those down into useful, smaller components.\n\ngasoline and other fuels can't be utilized because they are toxic and/or require a strong chemical reaction to break the bond and/or the components of that mollecule aren't even useful for a human to digest. benzine might be made of the same atoms as sugar and be a simpler molecule, but it's a bond that is very difficult to break, it's toxic, and there wouldn't be anything usable by your gut if it was metabolized.",
"A better example would have been cellulose. Humans can't break down cellulose even though it is made from same sub-units(glucose) as starch and glycogen. Cellulose has [different kind of bonds](_URL_0_) and humans don't have enzymes that could break these bonds. Plain sugar is essentially just glucose molecules and doesn't need much breaking but starch does need enzymes to break.\n\nEDIT: I have been corrected. Normal sugar is glucose+fructose",
"A friend of drank a liter of transmission oil on a drunken dare, other that acting like a laxative, he didn't get any adverse effects. He drank a liter of regular motor oil once as well. ",
"The digestive enzymes in your body are specific to certain orientations of certain atoms within a molecule. They facilitate the breaking of specific bonds in predictable specific orientations in order to break down molecules for energy. For example, starch is an energy dense food source for humans because we can break down the type of bonds connecting the individual sugar monomers. Cellulose, on the other hand, cannot be digested by humans. The only difference between the two is that the monomers are oriented 180 degrees around the backbone. Many herbivores have enzymes capable of breaking the bonds in cellulose, yielding energy needed for the organism. \n\n\nYour body can probably break down petroleum products, if we have enzymes capable of breaking the types of bonds they have. We probably do, but the intermediate products or by-products of these reactions are likely toxic or carcinogenic. ",
"The problem with petrol is that it contains some extremely volatile compounds that will harm *you* before you harm *them.*",
"No.\n\nSugars are carbohydrates: literally \"carbon-hydrate\" (carbon and water). They are often in the form of rings of 5-6 carbon atoms, with an H group and an OH group hanging off; with complex sugars and starches made by linking together the rings.\n\nFats have a short carbon backbone, and three hydrocarbon chains (carbon atoms in a line with hydrogen atoms hanging off of them) extending from the backbone.\n\nHydrocarbons, like methane (natural gas) and octane (car gas) are just hydrocarbon chains (normally; sometimes there are chains hanging off of the main chain).\n\nBoth fats and sugars/carbohydrates have \"handles\" that our body can hold on to to digest them; while hydrocarbons don't have those \"handles\". \n\nIt's worth noting here that cellulose is also a carbohydrate, but the way it is made, it forms sheets rather than chains of sugar-rings, so there is no \"handle\" for our bodies to grab on to for digestion.\n\n\nEdit: Thank you for the gold, kind stranger.",
"Petrol is made of hydrocarbons which have no chemical bonds that can be attacked by digestive enzymes. The more volatile components kill people by dissolving cell membranes. The less volatile ones are harmless and pass right through the body unaffected. Vegetable oil is made of triglycerides and fatty acids that do have chemical bonds that can be metabolized by digestive enzymes. Likewise for sugar and starches.",
"Chemistry gets much harder if you think of all organic compounds as being \"just carbon chains\". Depending on what is attached to the carbon, where, and in what sequence, the substance can change properties drastically. Like the other comments said, we could digest a lot of things that are toxic to us but only if they weren't *so* toxic.",
"Diamonds and coal are both carbon as well, but you can burn coal and not diamonds. One is translucent, the other is black. The point is that just saying two things are carbon chains does mean they have the same properties.",
"Just this morning I was standing in my kitchen thinking it's interesting that you can run both humans and diesel engines on fry oil. How did you know reddit? How?",
"It's not the carbon chains themselves - really everything that is or was alive consists of carbon chains. It's what's attached to them and between them - what's known as heteroatoms and functional groups. As the name suggests, functional groups determine the property of an organic compound(*). \n\nImagine it like this: The carbon chains are like a steel scaffold. But a steel structure doesn't do much on its own. What you put in it and on it determines what it does to a large part. Sure, a steel bridge needs to be roughly bridge-shaped. But it isn't much use if you don't put concrete or asphalt on it for cars to drive on. Or rails for trains to run on. Or a water-tight lining so you can route a shipping canal over it. It's all still the same underlying steel structure(**)\n\nTranslated into chemistry, heteroatoms and functional groups provide for shaping of the chain and alteration of its electronic properties (charges, what polarity, how much, where exactly), and that is where other molecules can attack for reactions.\n\nI've simplified massively, but I hope you got the gist of it. Essentially the individual atoms in a molecule don't matter too much, it's the sum total of them that makes the molecule and determines the properties. That's why people saying \"Oh but sustance X contains substance Y as part, which is also found in crude oil, which is poisonous\" are completely and utterly wrong. It simply doesn't matter, different molecules are different molecules.\n\n(*) organic as oposed to inorganic, in the chemical sense, not in the \"organic food\" sense\n\n(**) Apologies to all civil engineers. I know you'd have to construct a bridge carrying a shipping canal completely differently from a rail bridge. But I didn't want my example to get too complicated. Please forgive me.\n",
"The top answer doesn't tell you _why_ you can't digest them, and the answers that do tell you why, don't explain it like you're 5, so I'll try.\n\nYour body uses molecules called enzymes to break down large molecules into smaller ones that your body can absorb. Each enzyme works on a specific molecule and breaks it down into specific smaller molecules. They can \"recognize\" the right molecule by the shape and by certain parts of the molecules on the surface called functional groups. Functional groups are things like oxygen and hydrogen, for example. \n\nDigestible molecules have functional groups along their chains that the enzymes in your body can work with, and undigestible molecules don't. Petroleum distillates as a general rule don't have the right functional groups and/or are not the right shape.\n\nYou can see the difference by looking at (for exampe) [decane](_URL_3_) and [triglyceride](_URL_0_) or [starch](_URL_1_).\n\nTo give you an idea of *how* specific enzymes are, compare starch (which is digestible by humans) to [cellulose](_URL_2_) (which is not)."
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ct69ec | what's a truancy officer? how does that work? | I'm not American so I just heard that you have truancy officers, which sounds super weird and I don't know how it works, if they actually have any authority, what do they do, like do they drive around town looking for people? It all sounds very weird to me. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/ct69ec/eli5_whats_a_truancy_officer_how_does_that_work/ | {
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"In the US it is basically the law that children must go to school until they are at-least 16 (some are trying to make it 18). The fact it is illegal to not send your children to school if they are younger than 16 means they need to have someone enforce the policy. Truancy officers go and find students who are excessively skipping school. We are typically talking weeks out of school in a semester, not just cutting class once. Parents can also be fined and face legal problems if their kids don't go to school."
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aaa64p | how can a solar roof be cheaper than a regular roof? | Because of all the recent headlines about Tesla's solar roof and because econ stuff tends to fly over my head a little bit. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/aaa64p/eli5_how_can_a_solar_roof_be_cheaper_than_a/ | {
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"So this is how I understand it which could be wrong and if so someone let me know. A solar roof cost more upfront to build than an normal one but a normal roof isnt doing anything after words. A solar roof is making and storing electricity and depending where you live you are either getting paid by the state for that energy or you are using that energy yourself saving money on your bill. So in the long run you get money back from the solar roof ",
"It's not cheaper than a regular roof. But it does promise to be cheaper than a regular roof plus additional solar panels. At the present, however, it is more expensive, but looks a lot nicer than solar panels attached to rails placed on an existing roof.",
"A few factors, I will list from least complicated to most complicated. Not all may apply.\n\n1. Does the solar roof save you money? You are generating electricity which you will use to do things like browse reddit. Normally you pay the electric company for the electricity. Now you don't pay them or pay them less. For example my electric bill is $160. If I generate that much electricity I don't have to write a check for that.\n\n2. Does the solar roof generate you income? Some areas let you hook up your solar panels to the \"grid\". Most houses are connected by underground or above ground power lines. You can receive electricty but also send electricity. In some cases the power company will \"buy\" extra electrity that you are not using. You are basically sending extra electricty to your neighbours.\n\n3. Do solar panels last longer then a normal roof? There is an idea of deprecation. The idea is that an item decreases in value over time because things wear out. That pair of socks under the Christmas tree. It's nice and soft because it hasn't lost its fluff in the drier. Wash it 50 times, it starts to feel like an old sock. It may look the same but its not as nice. You can therefore think about how much value a sock or a roof looses based on when you will have to replace it. Roof's last typically 20 years. So you can think about spreading that cost on a yearly basis. Solar panels if they last longer then 20 years, therefore might cost less per year. They depreciate more slowly. Let's say they last 30 years. Well if you spend normally 5,000 to roof your house. Well 5,000 over 20 years means it costs $250 for each year it lasts. If a solar roof costs $7500 but is spread over 30 years it would also cost $250 dollars every year.\n\n4. Does your solar roof qualify you for tax credits/incentives? In order to encourage you to have an environmental impact some governments (local, regional, state or national--depending on where you live) may give you incentives to pay you back for some of the cost. This can mean less taxes payed or a subsidy to help make the solar roof cheaper. This helps save you money indirectly, but still makes the investment cheaper. \n\nTLDR So these are 4 ways that a solar roof could be cheaper long term than a normal roof. It can save on your electricity bill, it can generate money if you sell electricity you make, it can cost less per year because you replace it less often, and it can qualify you for tax breaks or government subsidies. ",
"It’s not at all. It’s the same price basically as a real slate roof. Real slate is one of the highest priced products you can install on a roof besides copper. \n\nSource: I own a roofing company. ",
"The idea is over the course of the life of the roofs.\n\nIf the roof last 30 years, take the cost of the roofs, plus the solar panels, and the electrical bills over that 30 years. Compare it to the cost of an identical house's roof and electrical bills without solar.\n\nThe idea is that after 30 years (ideally far less than 30 years), the total cost of the house with solar will be less than the house without solar.",
"Hah! Roof! Over my head! Get it.....?",
"Technically because it helps pay for electricity over its lifespan. However normal roofs + panels are a much better option than teslas options.[Here is a comparison by forbes.](_URL_0_) \n \nThe Tesla Solar Roof costs $55,600 installed \nThe Federal Tax Credit reduces the installed cost by $14,200 \nThe net cost of the Solar Roof after the tax credit is $ 41,400 \nThe total value of the solar energy generated over 30 years with 8 kW of power is $ 43,100 \nThis means the total financial benefits over the 30-year useful life of the Tesla roof-integrated solar energy system is $1,700. \n \n**The total financial benefits over the 30-year useful life of the Tesla roof-integrated solar energy system is $1,700.** \n \nBased on Geostellers price estimation on the other hand. \nButch would pay $38,000 to re-roof his home and install solar panels. \nHis Federal Tax Credit would reduce the installed cost by $10,200. \nThis brings the net cost of his roof and solar panel installation down to $27,800 \nThe total value of the solar energy generated over 30 years with 10.8 kW system is $61,400 \n \n**The total financial benefits over the 30-year useful life of the standard solar panels on Butch's newly installed roof is $33,600.**\n"
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2et78q | how can the humble bundle sell $260 worth of steam games/dlc for only $15? | Title. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2et78q/eli5how_can_the_humble_bundle_sell_260_worth_of/ | {
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"They're not physical objects. It doesn't cost anything to copy a file so people are still making money.",
"Companies that publish the games sign on to these things because it'll get them way more revenue in the long \nrun.\n\nLet's say Steam bundles 10 games for $15 when they normally sell for $200 in total. \n\nWhen you shell out your $15, each of the ten games get $1.50 each and Steam keeps $0.50 so each publisher of each game gets a buck. The odds are VERY good that most of the people who bought the bundle would never have bought any one game by itself, either because they aren't interested enough in it or because if they were interested they'd have already bought it anyway. It's the BUNDLE they're usually buying, and because Steam doesn't know or care what particular titles are of the most interest, each one of the titles in the bundle gets a share of the revenue.\n\nSo the publisher has made a dollar in revenue off of a sale that they otherwise would not have made. And because Steam's doing all the work of delivering the software to the customer and has already taken its cut, that publisher's cost is *zilch*. The game's already done and Steam looks after all of the media and shipping processes, so each additional copy costs nothing to sell electronically.\n\nThe publisher's revenue and profit is one dollar and, bonus, they just sold one of their games to a new customer who may or may not play it, and perhaps will like it if they do and buy its sequel. Win, win and win - and win for Steam too because it made some money off of hosting the sale.",
"Most games that go on sale have been out for a while already and have hit their breakeven point, so any sales after that without extra costs (shipping, physical copy) is just profit.",
"I think everyone here is answering they **why** and not the **how**.\n\nI don't really have a 100% positive explanation for the how but hopefully someone who sees this will. My educated guess would just be that the publisher is allowed to price their game how they want in a sale, and if steam does earn a profit from this then steam will allow the product keys to be used on its system as well.\n\nThen the why comes in, and because selling thousands of copies at $15 is better than selling zero copies at $260, given that you do not incur any more costs as a creator.",
"For the tldr; if you made a game, made a profit, although no one bought it anymore, can do a flash sale make $2 each sale and sell 25,000 would you do it?\n",
"Price discrimination. Sellers know that different buyers are willing to pay different prices for the same item. To maximize profits, they devise schemes to charge different prices to different buyers based on their assumed willingness to pay.\n\nThe shoppers who search bundles care about one thing: price. Not only are they bargain shopper, but they probably haven't played any of the games in the bundle. Thus not only are they looking to pay less, but they're uncertain about whether or not they even want the game so they will be willing to pay less due to that risk.\n\nThe shoppers who buy individual titles know what they're looking for. They know enough about the game to search for it specifically and have probably already played it. They know what they want and price is not as much of a concern. Thus they are likely willing to pay more.\n\nOther industries do this too to a much more complicated degree. Airlines frequently quote different groups of people up to 10 prices for the exact same seat on the exact same flight."
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xcnv3 | small-angle approximations | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/xcnv3/eli5_smallangle_approximations/ | {
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"IMO, [this article on small angle approximation](_URL_0_) is pretty schweet (w/ \"pretty schweet\" = \"one of the few mathy pages on Wikipedia that isn't just a bunch of hateful gibberish written by math majors\"). \n\nIs there something in particular that's troubling you about it?"
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4a7mmp | how is it that many comedy writers are also skilled comedy actors? | Examples include Conan O'Brien, Tina Fey, Larry David. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4a7mmp/eli5_how_is_it_that_many_comedy_writers_are_also/ | {
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"Most comedy writers aren't skilled comedy actors. Some of them are. The ones who are also skilled actors are the ones you know about because they're in front of the camera.\n\nAlso, Conan O'Brien isn't really an actor.",
"Most comedy writers have to prove their jokes are funny. The easiest way to prove your jokes are funny is to deliver them in front of an audience, as in stand-up comedy. Many talent agents take in the stand up shows and will sign the writer to whatever he can get him. Most of the time it will be writing jokes for others, but if the agent can get the writer in front of a camera, more power to him. ",
"I think it's simply that the fundamental underlying skill behind both is having a sense for what's funny.\n\nIt's probably also overperceived. There are a few prominent writer-performers, like the ones you mentioned, but for every one of them there are probably a dozen actors who can't write and a dozen writers who can't act. Not to mention that Conan O'Brien isn't really an actor (he's a fantastic host but hosting isn't acting) and Larry David happily admits he has zero range (like Jerry Seinfeld, he's only really known for playing an exaggerated version of himself in his own project).",
"A big factor is the delivery of the jokes. A lot of the nuances of comedy won't be present on the script, or may be difficult to convey to the actors, especially if the writer isn't present. Think about all the little pauses, facial expressions, voice tones and physical stance of the performers in your favourite sketches-- that's what makes the comedy as much as the lines. Writers know exactly how the joke works in terms of these little cues as they wrote it and know in their minds how it should look. The mark of good comic (non-writer) actors is the ability to either get on the writer's wavelength, or bring their own nuances and delivery to the lines to make it funny."
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1wk6y2 | what happened to gandalf the grey in fellowship of the ring? why did he come back as gandalf the white? | I was really thinking about this today. Sorry if i got the names wrong, i don't know much about it. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1wk6y2/eli5_what_happened_to_gandalf_the_grey_in/ | {
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"He killed the Balrog, and died in the act of doing so. He left the World, and was sent back by Eru Iluvatar (God) with enhanced power and authority. The Elves of Lorien, recognizing his newly-enhanced authority, clothed him in white and gave him a white ash staff, and called him Gandalf the White to symbolize his taking the head of the Wizard's Order from Saruman, formerly called the White but now calling himself Saruman of Many Colors.",
"If you have read the Silmarillion, you know that Gandalf is not mortal but rather Mayar, a minor spirit. He doesn't 'die' when he fights the balrog found in the Mines of Moria. . .he goes through a transformation. That is why his references to himself and his identity are so cryptic and that is why he emerges with vague memory of his former incarnation, initially.",
"He soloed a raid boss, got all that experience and gear and leveled up. \n\n",
"I just want to say that this is the most thorough and well thought out discussion of a two sentence question that I've ever seen. Well, well done folks.\n\n"
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3emvq0 | why is there water in the toilet before even using it? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/3emvq0/eli5_why_is_there_water_in_the_toilet_before_even/ | {
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"It's to prevent sewer gasses from getting into your bathroom. The U-bend of the toilet plumbing keeps water between you and the sewer and that keeps the noxious gasses out. "
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9dg7zt | what happens if you take a sleeping pill right after having a long sleep? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/9dg7zt/eli5_what_happens_if_you_take_a_sleeping_pill/ | {
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"What do you mean by sleeping pill? There are several different drug classes used to make one drowsy. ",
"Depends what pill you take and if you stay in bed or not. If you take something like an OTC antihistamine based sleep aid, you’ll most likely feel very drowsy and lethargic all day. If you take a proper benzodiazepine based hypnotic and stay in bed, you’ll knock out for sure. It depends on how active you are, what time of day it is, what you’ve had to eat and how much sleep you had prior.",
"This is very dependent on the sleeping pill in question, some of the tamer varieties try to trick your brain into thinking It’s sleepy which works better the sleepier you are (probably wouldn’t do much right after a night’s sleep). Something more hardcore with more of knockout effect could put you to sleep pretty effectively (imagine anaesthesia), though meds that strong would likely not be given out on a whim or for long periods.",
"There's no straight answer for this question unfortunately. There are quite a lot of different types of sleeping pills and everyone reacts to them differently so it could range from it having zero effect at all, to making you feel like a zombie for half the day, to knocking you out of course. But the worst side effects of sleeping pills are the blackouts where you are up and awake but have zero recollection of what you did once the drug wears off, and of course you are walking around high as hell. It also makes you extremely impulsive, sometimes paranoid and you can even have extremely vivid hallucinations in some cases. But not the good kind of hallucinations so I definitely don't recommend it. There are actually quite a lot of cases of people taking sleeping pills and waking up in jail. ",
"[Melatonin: Much More Than You Wanted To Know](_URL_0_) explains a bit about how melatonin works. Melatonin is a hormone that influences your sleep cycle. It also specifically addresses your question:\n\n > What if you want to go to sleep (and wake up) later? Our understanding of the melatonin cycle strongly suggests melatonin taken first thing upon waking up would work for this, but as far as I know this has never been formally investigated. The best I can find is researchers saying that they think it would happen and being confused why no other researcher has investigated this.",
"I used to buy all generic pills from the drug store. All of the bottles and many of the pills looked alike. Had a headache early one day at work. Took what I thought were two generic Aleve but ended up being two generic Tylenol PM. Longest fucking workday of my life.",
"I've taken half a prescription strength sleeping pill two times in my life and both times I couldn't wake up for at least 24 hours. I might just be super sensitive to them but I can say with great certainty I'd just fall back asleep, no matter what I was doing, if I took one right after waking up. I think it really depends on the person and the strength of the pill though. ",
"You'll likely just feel tired. Unless it's a very strong pill in which case you will go out again for a few hours and then feel like complete shit. ",
"Depends. Some are strong, some are laughable.\n\nI once found a whole sheet of 2 mg flunitrazepam (Rohypnol) - I remember taking the first one (tried to make a live thread of the effects but lost the ability to type within 30 minutes). Don't remember a single thing for that fortnight. Nothing - don't know what I did. Maybe I was mostly sleeping. Maybe not. Dunno. Incredibly powerful drug. \n\nI take reasonably large doses of quetiapine (Seroquel) (200 mg/day minimum). If you aren't used to it and you took another dose after you woke up, it would knock you straight back on your arse. But I'm used to it and if I took more when I woke up, I'd just feel tired all day.\n\nI used to take a fair bit of clonazepam, which is in between the previous drugs I mentioned. I was always tired on that stuff. And taking more when I woke up would absolutely make me sleep again. I spent days at a time in bed - only getting up to piss (which I cannot remember). Not something you want to make a habit of.\n\nThere are so many drugs and each one is different. You can't really make a hard rule for all inclusive.",
"I've mistakenly taken Ambien twice right away in the morning, accidentally mixing it up with my Lipitor. \n\nI thought about forcing myself to throw up, but I powered on through it. 30 minutes of intense sleepiness, followed by 30 minutes of intense goofiness, followed by a nice warm fuzzy feeling. \n\nYou can power through it if you want, or you can give in and go right back to sleep. ",
"I accidentally took an ambien one morning, mistaking it for my thyroid pill. No choice to stay home - I was in the military and my office was on an inspection deadline. The first two hours of work were excruciating to power through. I felt like I was trying to function after an all-nighter. I eventually rebounded, but I wasn't right for a couple of days.",
"You might spray Febreze on your frosted flakes before eating them. Thanks Ambien, I really enjoyed that floral crunch.",
"When I had brain cancer they would give me a liquid Benadryl because I was allergic to my chemo. Would put me straight out."
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1okmah | how did the world clean up in the aftermath of world war ii? | In the utter chaos and destruction that was World War II, how did the world and it's governments clean up and return to normal? (Or some *form* of normal.) | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1okmah/eli5_how_did_the_world_clean_up_in_the_aftermath/ | {
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"Three main points\n\n1. Economic recovery. The US economy actually benefited from the war, because higher levels of investment in manufacturing increased output and productivity. Europe, however, was destroyed. The Marshall Plan of 1948 gave huge loans to western European countries (those behind the Iron Curtain were effectively forbidden from taking the loans by the USSR), which helped them to rebuild and get back on the path to economic prosperity. The UK only finished paying it's loans back to the US in the early 2000s.\n\n2. Demobilisation. Countless soldiers had to be discharged. This was often a messy business, because jobs and homes simply weren't there waiting. The GI Bill was meant to solve some of these problems.\n\n3. Political readjustments. Germany was occupied by France, the UK and the US for several years, until the three zones were combined into West Germany. De-Nazification had to occur, whereby anyone running for government positions had their background checked to make sure they hadn't been complicit with the Nazi regime.",
"With the help of the parts of the world that weren't hit all that badly, which really works out to be the US. America spent hundreds of millions of dollars to help Western Europe and Asia rebuild.\n\nCountries that could not afford it went through rougher times: The UK underwent significant decolonization in the aftermath of the war, and while the Soviet Union tried its best to help its own allies, they themselves struggled.",
"The Allies ordered all german women between 15 and 50 to remove the ruins in the bombed cities. Those women were called [\"Trümmerfrauen\"](_URL_0_), which could be translated to \"ruins women\". Those Women found a lot of recognition during the postwar years.\n",
"They're still picking up undetonated bombs.",
"What about the USSR?",
"In addition to some points already made here, it's worth noting we're still literally cleaning-up battlefields from WWII (and WWI even). Unexploded munitions, land mines, mass graves, chemical remnants, and heaps of scrap metal dominant former war zones, posing serious risks and transforming local life.\n\nCheckout the section on Stalingrad in [Aftermath: Remnants of War](_URL_0_). ",
"I'll let you know when we're done.",
"Does anyone have insight into how they actually physically cleaned up everything? ",
"Slowly in a word. It took a long time to recover from the war and in some ways some places never recovered. In Britain, rationing was in effect for years afterwards. Temporary homes, called pre-fabs, were installed to provide housing. These were intended to last 5 years or so, until proper houses could be built, yet people were still living in them 60 years later and probably still live in them today. In some places blocks of flats were built to provide homes, at least as part of post-war regeneration, and that is generally viewed as a bad move. \n\nSome things haven't been rebuilt and never will. One redditor posted a photo of a church that had been destroyed in the war, it's now the centre of a roundabout in that town. It will almost certainly never be rebuilt, because there's little reason to."
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2ohc2r | what would happen if there was a fire on the international space station? how is this prevented? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2ohc2r/eli5_what_would_happen_if_there_was_a_fire_on_the/ | {
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"If a fire were to break out on a spacecraft in orbit, astronauts would fight the flames in slightly different ways than they would on Earth. Fires in space are not the same as fires on Earth, but the best way to fight any fire is to keep it from starting.\n\nAs hot gasses from a flame rise, they create air currents that bring fresh air to the fire. This buoyancy is what makes a flame long and pointed here on Earth. In low gravity situations, there is no buoyancy from flames.Convection, the movement of air, is an important way that heat is transferred to other spaces. Without air, fires don't spread as rapidly. Ventilation fans on the Space Station replace natural convection and can supply the air a fire needs to burn. Under these circumstances, the fire can spread in any direction, rather than just upward.\n\nThe flame's unusual shape creates different amounts of soot, smoke or harmful gases. \"Combustion in microgravity is a very difficult problem, and there are a lot of engineers and scientists working to understand it better,\" said Gary A. Ruff, aerospace engineer at Glenn Research Center's Microgravity Combustion Science Branch in Cleveland, Ohio.\n\nAll materials going up into space are tested for flammability on Earth in a special test chamber and ignited with a hot wire. Some items are so important to a mission's success that they're permitted to travel to space despite being flammable.\n\nDetecting a fire in space is also different than on Earth. Here, smoke detectors are installed on the ceiling or upper section of a wall because that's the direction in which smoke travels. In space, smoke doesn't rise, so detectors on International Space Station are placed within the ventilation system.\nWhile the ISS hasn't experienced a fire, a significant blaze did take place in 1997 on the Russian Space Station Mir. The fire came from an oxygen generator, where the oxygen supplied a ready source of fuel. Tests showed that the generator had to run out of oxygen for the fire to burn out. If a fire were to occur on the ISS, the astronauts would become firemen and follow a three-step response system.\n\nFirst, they would turn off the ventilation system to slow the spread of fire. Next they would shut off power to the effected unit. Finally astronauts would use fire extinguishers to put out the flames.\n\nRuff says that while safeguards have been in place to prevent a fire from occurring on the Space Station, it's comforting to know that astronauts could respond to an emergency because they've prepared for any eventuality.\n"
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2jy7it | how can a person, who is close to dying, decide when to "let go"? | I have read/heard so many stories of how "Uncle George waited to see his son before he 'let go' and died". How can a person decide when to "shut off" their bodies? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2jy7it/eli5_how_can_a_person_who_is_close_to_dying/ | {
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"They can't. Your example is anecdotal and not based in reality. People die as a result of their brain ceasing activity due to some kind of organ failure, which is not the result of a conscious decision.",
"I have not personally experienced a decided \"shut off\" and agree it is anecdotal. \n\nI was reading a thread on a different subreddit and the comment was about a daughter visiting her ill father in the hospital and she wanted to stay with him overnight, but he asked her to go home to be with her kids. She obliged, then he passed away that night while she was gone. Someone else commented stating how so many ill people 'wait' until their family is not present to pass away. That person said they were in hospice care, so they experienced this happening a lot.\n\nI guess I'm curious whether this has any scientific backing, rather than anecdotal merit."
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1iaov7 | the different levels of video quality (360, 720, 1080, etc.) and what they represent | What are the units used, and what do the p/i/etc tagged on at the end represent? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1iaov7/eli5_the_different_levels_of_video_quality_360/ | {
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"The number is the number of vertical lines in the resolution.\n\n'i' means interlaced - in a 1080i broadcast, the odd numbered lines (540) are transmitted in one frame, the even numbered ones in the next. The display has to combine them to show a full picture. It causes lower video quality.\n\n'p' means progressive, i.e., not interlaced. All lines are sent every frame."
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11bdly | why are there no bandwidth limits on fm radio, but 3g/4g bandwidth is so precious? | Title says it all.
I can listen to music on FM radio receiver all day with no bandwidth limits to worry about. What's more, it's not affected by millions of citizens doing the same thing at the same time.
But voice and data networks on the other hand, are constantly constrained by bandwidth.
Why can't we use FM radio like wireless technology for voice/data ? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/11bdly/why_are_there_no_bandwidth_limits_on_fm_radio_but/ | {
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"FM radio is a one-way broadcast.",
"When people are listening to the radio, they are only listening. They are not sending radiowave signals to the radio station. When you are talking on a cellphone, you need to exchange information with someone else. Basically, one-way communication (FM radio) vs. two-way communication (cellular phones). Furthermore, radio stations are localized while cellular networks reach across the country.\n\nAs you can imagine, it is much simpler to have a radio tower just broadcasting signals than to set up a cellular network where hopefully someone on one side of the country can communicate with someone on the other side. For cellular networks, you'll need to be able to identify the various signals and make sure you send them to the right destination.\n",
"Because FM/AM radio is one way.\n\nThere also are bandwidth limits (which is one of the reasons why there are different frequencies for each station rather than a toggle to flip between them, as the frequencies don't interfere with each other), but at **absolutely no point** does your radio push anything back to the station.\n\nYour radio cannot submit a request for the next song, for example. You cannot type into your radio and get a response from the DJ. Hell, no one at the station can even track that you're listening. They have no idea.\n\nIt's basically the difference between a conversation and one person shouting in a lightless room, where no one is allowed to talk back. The shouter has no idea if anyone's listening and cannot interact with them even if they are.\n\nNow, years ago each station was more or less independent while these days lots of them are owned by a single corporation that pushes it's own setlist out, but generally speaking each station is still independent. If every radio station in the East goes down, absolutely nothing happens to the stations in the West. They simply have nothing to do with each other.\n\nIn contrast, the Internet and the Phone System are all about interactions with each other. Your device is not just pulling data in, but pushing data out to a tower. The tower is constantly pushing data out (and remember, each data push and pull is completely independent of the others, as everyone is requesting different data) and pulling data in from the rest of the internet. If that backbone from the tower to the carrier's servers goes down, the tower cannot connect to the internet and internet service is lost.\n\nTo compare it to the Radio works if you imagine the radio station is pushing out thousands (if not tens of thousands) of completely different, completely independent radio playlists to each listener based on what they request. And check their mail for them. And deal with incoming phonecalls. And pornography. Oh man, the pornography.\n\n*edit* I completely forgot my point. My point is that bandwidth is so precious on the 3G/4G networks because it's a limited resource. If we use the Garden Hose analogy, the 3G/4G hose is bigger than the Radio Hose. The difference is the Radio Hose only has water coming out into the flowerpots. The 3G/4G hose ALSO has water coming BACK in the hose from the flowerpots, and if they don't catch enough water coming back in the pipe, the flowerpots will say \"Fuck You, buddy!\" and start getting their water from another hose and.. okay, the analogy has completely broken at this point. Still kinda works, I guess.\n\nBut yeah, information they're taking in takes up where information going out could go. And during that guy playing Farmville on his hotspot, that chick trying to get Dethulchur tickets by spamming the refresh button, that chick over there streaming her Pandora shit on the bus, and some other jackass obsessively watching Porntube in the goddamn bus station like an asshole, you've also got 10 people having voice conversations. ",
"FM is limited by bandwidth. There's only so much information they can pump over the air, which is why radio broadcast isn't CD quality. Digital radio is attractive because data can be compressed, so more information can be supplied over the same limitation. But I can understand how you've not noticed the bandwidth limitation.\n\nAnd as others have said, it's public broadcast, the station controls the entire channel and all the data that's on it. They're limited by FCC regulation as to what type of data they can transmit and how.\n\nWhen you take a shared transmission channel, either an ethernet cable or a wifi tranceiver, everyone wants to send and receive their data as much and as fast as possible, and everyone has to take turns. The more people who want to use that channel, the more turns that have to be taken, the longer it takes to get to you.\n\nAlso, take note what frequency your wifi device is operating at. You can use your laptop to scan the neighborhood and see. Wifi operates across 11 channels or so. If everyone is using the same channel, it doesn't matter if they're on different Wifi tranceivers, you're all overlapping, and slowing each other down. The tranceivers can't tell the difference. You can change the channel of your tranceiver.",
"The other explanations that have been listed are good, I just want to add one term- multicasting. With FM, every single person listening is receiving the same signal. Not only is it one way, but it's a single signal for every listener. If I am downloading something on my phone, and my neighbor is downloading something, the infrastructure needs to provide enough datarate for both things simultaneously. If we're both listening to the same radio station, we don't need separate signals, we can share the one signal.",
"Everyone saying it's because it's one way. That's not really it. \n\nThe reason why you can listen to FM radio all day, is that there is only 1 station on a frequency that everyone in the city is listening to. If 93.5 is broadcasting REM music, everyone tuned into 93.5 hears REM. What do you have to do if someone wants to listen to country, they have to go to a different station, say 107.3.\n\n(Warning, 5 year old answer) Now, with you don't want everyone in the city listening to your Pandora. So, you have to have your own radio station, just for you. You list to 3G on 107.3, Bob listens on 93.5, Jane on 101.1. But, there are only so many channels available. So, to get everyone in the city on 3G, Verizon says, ok, you can listen on 107.3, but you can only do so for 15 minutes a day total. That way, everyone else gets a chance to listen too. You don't have to do it at one time, but you only 15 minutes in a day. That's like a bandwidth cap.\n\nSo, even when traffic is one way, there's just not enough bandwidth for everyone in the city to have unlimited traffic just for them, in either 3G or FM. IFFFF Everyone in the city wanted to listen to the same 3G signal, they could, all day. ",
"Think of it like a water slide. One big slide everyone goes down with one ladder everyone goes up is fine, but a bit boring. But if everyone needs their own slide and ladder, things get complicated really really fast and you run out of room.\n\nFM is the one way big slide.\n\n3G/4G is the plethora of slides taking up every ounce of space available.",
"Explaining it like for a 5 year old...\n\nThink of FM radio like a highway, with about 20-60 lanes. Each radio station you can listen to is using up one of those lanes constantly, making the music or voice available to anyone who is by the side of the highway. \n\nHow long this highway is depends on the power of the FM radio stations, that's why in one city you can listed to a radio station on a frequency and in the next city on the same frequency you might listen to another radio station.\n\nThe highway for FM radios is between 87.5 Mhz and 108 Mhz, you can see those numbers on your radio.. each lane takes about 0.25-0.5 Mhz so you can see the highway can have about 50-75 lanes. \n\nNow, everybody can listen to the radio station but there's no way for you to give feedback, they're just transmitting information, and the same information is received by everyone tuning to that radio station.\n\nWireless internet is a bit different. \n\nNot only you have to \"listen\" or better put to receive the content of websites, but what you receive might be different than what everyone else wants to listen to. So each person has to have its own lane of highway to receive the content. At the same time, you need to tell the station what you want to listen to: your device has to tell the radio station to change the website and then the radio station has to send you, and only you, the contents of the website. \n\nYour phone connects to a mobile phone tower / antenna, which is like a highway with lots of small lanes. Each phone that connects to this mobile phone tower or antenna gets allocated two of those highway lanes, one for the data it sends to your phone, and one lane for phones to send requests to it. \n\nThis miniature radio station (the cell tower) has a much lower transmitting power and your phone is also much weaker at sending data to the antenna. For example, your FM stations cover an area of up to 30-50 miles around their antenna, while cell phone antennas usually cover only 1-5 miles.\n\nThis lower power means the \"highway\" is shorter, just those 1-5 miles. Also, the highway it makes might be wider, with maybe 100-200 lanes, but unlike with FM radios, each phone that connects to the antenna and wants to be on the internet has to receive one of those lanes on the highway to send requests to it. \n\nThe antenna creates one big lane for all the data going to all the mobile phones (let's say a lane as wide as 100 fm radio lanes) and then takes the rest (which is about as big as 10-20 of those fm radio lanes) and creates a few hundred very small lanes for the phones to send their requests to the antenna.\n\nOnce all those small lanes are occupied with phones demanding pages from the Internet and the antenna sends content through that big wide lane to all the phones, it's done, it just can't handle more phones. \n\nThis is why the bandwidth costs on wireless connections... if it was very fast and free, a few phones would connect the antenna and use that big lane of highway to receive data and nobody else could connect and get pages on their screens. There's only so much bandwidth, so many lanes on the highway.\n\nIf one of these antennas are full of phones connected to the internet, the phone company would have to install a new antenna or several other antennas and these are expensive. "
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3q3bng | what do rich people get in return for donating money to someone's presidential run? | I'm a Brit who has very little knowledge about the presidential race. But I know that people give money to people running for the top job. Do they get anything back for their financial support? Or is it just to get the guy they want to be President? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/3q3bng/eli5_what_do_rich_people_get_in_return_for/ | {
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"Its sort of the equivalent of charity. You do it to show your support because you have the money. A campaign with donations gets more circulation of ads, hire more people to work on it, and etc. You need lots of money to run a campaign. Besides a public thank you or being invited to a party, there SHOULD'NT be any other return to your contribution. You contribute to see them win.\n",
"If you are a big enough donor, you might get a meeting (or several) with the candidate, and if they win, you could \"coincidentally\" be appointed as a U.S. ambassador overseas.\n\n[Source](_URL_1_)\n\nAlthough, it's also beneficial to the US to appoint rich people as ambassadors: they throw so many parties, they often will go over-budget and [pay a lot out of pocket.](_URL_0_)",
"Ultimately, they get money back. By supporting a candidate, they hope the candidate, if elected, will help pass laws favorable to the giver. The laws they hope for will help the givers' business interests make more money, make money easier, or pay fewer taxes. \n*there is no other reason for business interests (corporations) to give money to a candidate.*",
"For example, a donor might give millions knowing that the candidate would lower a tax that saves them millions x2.",
"If you give enough, you get the ability to convince politicians to vote in favor of your beliefs or things that will benefit your business. Most politicians are \"bought\" in this way and vote to please their sponsors."
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2l4r11 | how does american college football work? it seems like organizational chaos. | I don't know what the hell is going on. Is there a winner? There doesn't seem to be any definitive champion, and it makes me confused. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2l4r11/eli5how_does_american_college_football_work_it/ | {
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"So, it sort of is organizational chaos. Universities form groups called \"conferences\" which become sort of like their league, and there are many leagues, since there are only 12 regular season games, and far more than 12 unis in America (over 100, actually) that compete at the top level. These conferences are somewhat analogous to the European soccer leagues -- there are numerous individual leagues, like the EPL, La Liga, Serie A, and so on, and they primarily play within their own league, although they do sometimes play teams of other leagues. Each conference crowns its own champion, usually by a conference championship game. \n\nInstead of the Champions League, however, as of this year we have a playoff, which for college football is a four-team single-elimination tournament, the winner of which is the National Champion. The four contestants in this playoff are chosen by a selection committee at the end of the regular season, but as this process is new this year, who knows how that works. In any event, winning a conference championship is sort of like winning a specific country league like EPL, but winning the playoff is like winning the Champions League. \n\nWe do have weekly rankings of all the best colleges, generated through polls of football coaches and sportswriters. This is generally how people keep up with who the best teams are; the closest analogues here are probably P4P rankings in boxing. \n\nThat's the basics..."
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j3xld | [li5]: how does hinduism work? no dumbed down buddhist explanations plz. those aren't the same. | I know Hinduism arose in ancient India and is one of the oldest religions of the world. That's all. Reincarnation, karma, Vishnu, Shiva, Brahman, Brahmastra? halp? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/j3xld/li5_how_does_hinduism_work_no_dumbed_down/ | {
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"Inside the body of every living is a **soul**. The **soul** is like the inside of your head, like when you read to yourself. Hindus believe that this **soul** never dies. It just picks a new **body** when your current body gets too old or you have an accident and pass away. And this new **body** can be any living thing. From another human to bug, or a dog, or a cow. This is why many people who practice Hinduism treat all living things with respect, because one day, it could be you."
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6bn5rh | why do our bodies sometimes get sharp pains in random places for a few seconds/minutes and then go away? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/6bn5rh/eli5_why_do_our_bodies_sometimes_get_sharp_pains/ | {
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"There are many reasons this could be happening. I the case where physiologically there is no illness taking place, sensory information going to the spinal cord and brain can be misinterpreted. In other cases the cause can be pinched nerves, random spasms of muscle fibers, muscle strains, fibromyalgia... The list goes on.",
"Well a little search gave me two reasons plausible reasons -\n \n1. It could be due to a phenomenon called \"referred pain\". It occurs when sensory information comes to the spinal cord as coming from one location, but is interpreted by the brain as coming from another location.\n \n2. This is applicable to only sharp fleeting chest pains and it is called Precordial Catch. It is a non-serious condition affecting the left side of the anterior wall of the chest. It is characterized by sharp chest pains, and usually affects children and adolescents, although it can occur, though less frequently, in adults. PCS manifests as a very intense, sharp pain, typically at the left side of the chest, generally in the cartilage between the bones of the sternum and rib cage, which is worse when taking breaths, or doing physical activity.",
"Does anyone know why shooty arse happens?",
"Alrite I'm going to jump in since everybody is asking these sort of questions. Sometimes I randomly get this weird sensation in my butt. In what I imagine is my prostate. No homo, feels pretty fucking good. What the hell is it? It happens to me randomly somedays more then other. Anybody have a clue what that is?",
"Edit 735: I tried writing a better ELI5 than the one I originally wrote. Added it below the original.\n\nThis is a favorite field of mine and also a difficult question to answer. I'll do my best, but I think I'll still leave you wanting.\n\nEven though we have nerves that we know that are related to pain (called C fibers), the processing of the feeling we call pain is much more complex than that.\n\nThe brain and the spinal cord (the central nervous system) do all the processing of pain.\n\nSo what can cause a random pain for a few seconds? Here are two examples, there are many more.\n\nA. A peripheral nerve (i.e, the one in the bottom of your foot) shooting while unprovoked or because of long term irritation.\n\nB. A sensory nerve (unrelated to pain fibers) shoots an electrical current towards the brain. Because of wrong processing in the brain, the sensory input is perceived as pain.\n\nSo these are examples to the \"how\". I feel that I cannot answer \"why\" with confidence. \nThere is a lot of research, and pain is something we are still trying to understand.\n\nThe guy in the next video is a leading researcher when it comes to pain, and he does a great job explaining it in this [TED talk](_URL_0_).\n\nHoped I helped a little bit, and sorry I couldn't give a more detail answer but my time is really short.\n\n\n\n**Better ELI5 I think:**\n\nImagine there are roads all around the body, going from all of your body parts (hands, feet, nose, liver, and so on) to your head.\n\nOn those roads there are trucks, coming from the small towns to the main station (the head) to unload their boxes with some electronics and food for the grocery stores.\n\nNow, in the delivery room in the main station there is a delivery guy, and he is busy as hell. He is trying to keep up with all that's going on, but he makes mistakes sometimes.\n\nSo sometimes, some boxes arrive not where they should be. So now, the local hotdog stand accidentally gets some new TVs, puts them on the grill and stinks the whole town.\n\n\nEdit: formatting\n\nEdit2: Trying to make things a bit clearer.\n\nEdit3: It seems it's much more interesting to answer questions on reddit than do whatever I was supposed to be doing. Thank you for the challenging questions, and I'll do my best to answer what I can.",
"I'd get stabbing pains in my side. Turns out I am constantly dehydrated. I never remember to drink. Drink more water kids. ",
"Omg yes have had the chest pain too! The horrible sticky kind where it feels like my lung is stuck to my ribs; and more commonly the lightening kind. Have figured it is related to my back, and the more I exercise (which is not a lot! Office based job etc ) and the more I strengthen my back/core, the less I get the pain. If that helps anyone.",
"Anyone sometimes get a stabbing pain in their belly button region that shoots up from their groin, and is made worse by leaning backwards / bending their back inward? ",
"Is it bad if I don't get those so called \"random pains\" ?",
"I get it in my ear, like someone just stabbed a knitting needle onto my head. A second later, gone. ",
"I get these sharp pains in my right shoulder every few weeks or months... It hurts so much that for those few seconds my body seems to feel disabled.\nThis has been going on for years but I never knew if it was serious or not, should I go see a doctor?",
"Also \"work, job\" related pains due to working(physical hard labor) your ass off, also causes these random pains to appear, I don't really get it much when doing office work, only pack on a few pounds due to being immobile... physical labor does keep me in tip top bro do you lift shape tho; only good thing I enjoy about it, no work out needed.",
"This is purely anecdotal but the vast majority of my day to day body pain including what op mentioned have completely gone away with regular fitness activity. No more Charlie horses in the middle of the night, no more back spasms at work, etc.",
"Sometimes (once 3-4 month) i get pain in lower abdominal slightly to the left or right. Im afraid it might be stones",
"I have this in my eyes. Mostly when I'm in a environment where the wind is dry and after a busy day. Sharp pain for a couple minutes with my eyes reacting with tears. More people experiencing this?",
"It is like a brand new pc has delay like 0.1 sec without any reason and you got heart attack for 0.1 sec., but sometimes it just delays, give errors. no-body is perfect, just go with it :)",
"Body is complicated system and sometime things like nerve system get confused by sending pain sensation to different part body or even wrong interpretations. For example referred pain, you feel pain in different part of body away from the original source. There are some theories explaining why. Like some said because some body parts and organs share same pain pathway and confusion happen from time to time like get misplaced in brain and spinal cord (convergent theory). At the end no body know 100% why",
"Random pains happen to me a lot. Well, enough for me to have wondered this same question. I always assume I'm dying or having a stroke or an aneurysm. Last night I kept getting dizzy so I did the stroke check: both hands up, tongue out straight. I hate it because I have anxiety and these things almost always give me a panic attack. Twice in the last year I was sure I was having a heart attack :/",
"I've had this sharp pain in my ribs on my right side for as long as I can remember. When I started getting sick of the flu or some kind of cold it would trigger the pain. It's always been the way I knew in advance I would get sick before any other symptoms. Until one day I caught influenza and complicated into pneumonia. Needed antibiotics, cortisone, etc... It weakened my immune system. The pain in my ribs got sharper and sharper until after a few days I looked at my skin and realised I developed shingles on that one side of my ribs. So after all these years, the virus was dormant in my nerve endings and whenever I got sick it would be enough to annoy it a little bit but not enough to wake the virus until that one day. ",
"I began getting horrible, short lived headaches a few seconds/ minutes at a time, turned out to be a brain tumor. You should get checked out. ",
"Do get random joint pain in my arms and legs. It's a bit odd, it's only seems to hurt bad if I focus on it, if I distract myself the pain seems to go away.\n\nI am obese. So that could be a good explanation for joint pain.",
"My ex use to get random sharp pains all of the time (multiple times a day, and they'd make her jump out of her chair), but I've never had one ever so this post has been pretty interesting.",
"Second question. Why does my body get specific full length pains every winter, excruciating, full arm pain, but my doctor says its purely temporary muscle inflamation. That apparently happens. Every year. In winter. ",
"Most likely it is because your body needs water to function. Without enough water the \"gears\" aren't as lubricated. Staying hydrated will likely prevent it and relieve it. ",
"So is this why I constantly have really bad back pain all around my neck and shoulder blades that shoots around to different places all the time making it so I can't ever sleep or do anything productive without taking way too much advil?\n\nEvery doctor I've been to says nothing is wrong, X -rays come back showing no signs of damage or anything, and the chiropractor says I just need to keep returning to his office for treatments. \n\nWell not anymore because I've finally found the answer!! My pain receptors/ central nervous system wiring is just messed up! thats all!!!! I'm just all screwed up!!!!!!! NO BIG DEAL!!!!!",
"One of the many possible causes is also anxiety disorder. Cue brain zaps, cluster headaches, muscle tension.. ",
"Anyone else get a really sharp pain in the anus randomly?\n\nIt feels like a someone is stabbing your bunghole with a knife for like 2 seconds then it's gone. \n.",
"LPT: do not consult WebMD regarding any of this because if you do, you'll self diagnose 8 different kinds of terminal cancer.",
"It is because the brain's mental map is flawed in that area of pain. The degree of error correlates directly with amount of pain perceived.",
"Because you're just a bag of chemicals, little bro, and sometimes those chemicals make mistakes.",
"Ive got these sharp pains at the bottom of my foot which happens ever so frequently. They kinda feel like electric stings. Anyone know why?",
"I always imagine its a blood clot sailing through narrowly missing killing me or maiming me. Acute chronic stress releases cholesterol into the bloodstream which can clump up or attach to artery walls. ",
"So on Easter as I'm walking out of church I get this shooting pain up my hoo-ha, lasts about 15 seconds, never happened before or after. ",
"Sometimes I'll wake up and feel a horribly sharp pain in my inner thigh, near my groin. It hurts excruciatingly bad when I move my lower body, but goes away if I stop moving for a while. I usually wake up compulsively around the middle of the night and experience this as often as once per week.",
"A few years ago Keith Lemon started talking about 'shooty bum' on TV and I found out it wasn't just me that got random pains in the arse/ass, literally.",
"And the older you get, the longer these random sharp pains last. They still eventually go away and never come back, but it's unnerving when the pain lasts longer and longer.",
"Flash went back in time and created a flashpoint where you were supposed to die tragically but because of the timeline alteration, you don't die. You feel the reverse effect of that part of the body where you died. ",
"I want to take this opportunity to let people know about precordial catch syndrome. If you ever start breathing in, and there's a sharp pain near your sternum that goes away after shallow breaths to stretch it, or goes away after you bite the bullet and breathe in deeply to make a pop, that'd what that is.",
"I always thought it was because of Osmosis Jones missing a shot he took while chasing a bad guy"
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42ueg9 | why do hearts that we draw look nothing like the hearts in our bodies? | I've been wondering this for a while now because the human heart looks to me like half of the hearts that we draw during Valentine's day or whatnot. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/42ueg9/eli5_why_do_hearts_that_we_draw_look_nothing_like/ | {
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"The symbol has been around longer than the average person would know what a human heart looks like. There is speculation that this symbol resembles the Silphium seed, a plant which the Ancient Romans used for birth control. They used it so much it doesn't exist anymore. ",
"One theory, is that the shape of the heart developed from the now extinct Silphium seed. [Here](_URL_0_) is a picture of the seed on an ancient silver coin. If we are to believe some ancient sources, the seed was a very effective contraceptive, which as you could imagine, would have put it in high demand and would have associated the seed with sexuality and love.\n\nHowever, Silphium only grew in a small area along the coast of present day Libya and despite efforts to protect it, a combination of environmental changes, over-farming and politics made it go extinct around the 3rd-2nd century BC.\n\n_URL_1_",
"I have heard, and this really does makes sense to me is that hearts we nowadays draw are representation of a female bottom..."
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2tt2mh | what are the chances of finding drinkable water on a small inhabited island in the middle of nowhere? | Edit: Uninhabited*. I'm an idiot.
Say, my plane crashed/ship sunk/spaceship got shot down, but I survived and ended up on a small island of no interest to anyone, completely inhabited, far away from any continent. What are the chances that I'll find fresh water here? What does that depend on?
I'm particularly interested in very small islands, 1000 square meters and less, Would I just die there of dehydration?
(tried to search, nothing came up, not even on Google) | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2tt2mh/eli5_what_are_the_chances_of_finding_drinkable/ | {
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2t360l | how do countries transfer money to terrorists for hostage ransoms? | So say Japan decided to pay the $200m ransom to ISIS for the two hostages. How would they go about funding ISIS with kind of money? Surely it wouldn't be done with bank transfer and $200m in cash is just crazy.. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2t360l/eli5how_do_countries_transfer_money_to_terrorists/ | {
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"When Germany paid a ransom last year it was suitcases full of cash.\n\n_URL_0_",
"Cash is exactly what ISIS would be wanting. Not only would they not want any kind of electronic trail leading to their accounts, but the sort of people they're then going to spend the money on (illegal arms dealers, mainly) are also not likely to have easily-traceable bank accounts.\n\nThe money that doesn't get spent on weaponry and vehicles will then mostly be used as payments for those working for them, and bribes to police chiefs and government officials in the areas they control. Again, this is something that's much easier to achieve with cash, especially globally-recognised currencies such as US dollars or Japanese yen.",
"Is it possible for them to transfer the money in cash and after retrieving the prisoners announce \"The money is fake! Muhahahaha!\""
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3d7arr | why does cutting your hair make it healthier? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/3d7arr/eli5_why_does_cutting_your_hair_make_it_healthier/ | {
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"Do you have a citation for that? It sounds as though there must be some misunderstanding. To begin with, it's impossible to make hair \"healthier\". Hair is, in fact, dead.",
"Your hair starts to fray and split at the ends over time and do to certain conditions like heat or chemicals. If you cut those damaged ends off it prevents the frayed ends from continuing to split up the hair shaft. The hair follicle can then remain in tact and can grow normally\n\n[Split ends](_URL_0_)\n\nEdit: I guess I like to think if it like a frayed rope. If you do nothing to take care of the damaged end eventually the whole rope becomes frayed and weak."
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60kbal | why does a 4 oz (112 g) chicken breast have only 110 calories when protein is 4 cal/g and fat is 9 cal/g? | [deleted] | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/60kbal/eli5_why_does_a_4_oz_112_g_chicken_breast_have/ | {
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"A chicken breast isn't 100% protein. Usually, meat has around 20% protein content. Like human tissue, chicken meat also consists of a large amount of water, and water doesn't contain any calories."
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4h3hkp | how did people in the middle ages get up to go to work so early? i get that they probably got up with the sunrise, but surely this would have varied dramatically over the course of the year? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4h3hkp/eli5_how_did_people_in_the_middle_ages_get_up_to/ | {
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"The people of the middle ages did not get up and go to work \"so early\" , they got up at or around dawn. Yes this means that the time would shift throughout the year. You simply did less and sometimes no work during the winter depending on where you lived and what you did. \n\nIn cities there were jobs such as city watch (which was more about spotting fires than invading armies) that worked in shifts and would wake their replacements and sometimes wake specific people like bakers and such as part of their rounds. ",
"First, just to be clear, they had clocks in the middle ages. People could look at the clock tower and know what time it was. People could then walk around and wake other people up by making noise. And that *was* an actual job. And, believe it or not, there were people who's job it was to wake *those* people up. \n\nWithout clocks, there is no regular schedule, so you kind of have to go by sunrise/sunset. However, there are ways to make a clockless-alarm that'll wake you up after a specific amount of time. For example, you can make a candle that'll burn for the right amount of time, after which it'll burn through a string that holds up a weight that'll fall into a bowl and make a loud enough noise. Or you can make someone stay up and wake you up. \n\n",
"Well you would not have some asshole counting down the seconds until they can declare you are late for a start. You would get up because you were used to it, for most people there would be little comfort in not getting up for a while, we live in unimaginable luxury compared to those people. \nMost people worked the land, if you didn't get up and work you would not have enough food to survive the winter. \n\nAnother thing to remember is that with no artificial light no useful work could be done outside and only a few tasks could be done inside if you were doing well enough to have candles, most wouldn't have even that and what they did have would be smoky tallow candles of limited use. So in the winter people would have slept longer and stayed under whatever cloth they had to try and keep warm enough not to die and when the light came you'd work until it went again because you had too and because doing hard labour would be the only chance you had to warm up. \n\nLife was unimaginably tough compared to now, hence people sought solace in the idea that their hard short lives were a trial before they could go to heaven. "
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2d75bh | during hot weather, why does my house seem to get hotter in the evening even though it has cooled down outside. | Does the heat get transferred inward? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2d75bh/eli5during_hot_weather_why_does_my_house_seem_to/ | {
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"Could be any of several reasons: 1) there are things in your house generating heat (e.g. electric appliances, lights, people and animals); 2) residual heat from the walls and roof of your house radiating it back into your house; 3) if the sun is still shining, could still be heating the inside of your house faster than the heat can go back out the windows.\n\nEdit: spelling",
"Your house is decently good at insulating warm or cool air, and when it cools down outside, there is a bigger temperature difference between outside and inside your house, so it also just appears to be warmer than earlier in the day. And of course there is also all the equipment in the house that creates heat as was said by another commenter."
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79p672 | what is the logic in nature, where a lot of animals/mammals are giving birth to a lot of babies at once? they can't possible take care of them all. | Dogs/Cats/Frogs, etc.
Only reason I can think of, is so that there will be a better chance of as many babies as possible to survive the early days of their lives.
But on the other hand, it means that a lot of those babies will die a cruel early death (starvation, getting eaten, etc)
Edit: Thank you all for the answers | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/79p672/eli5_what_is_the_logic_in_nature_where_a_lot_of/ | {
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"There is something called [r/K-selection](_URL_0_). Some species have a K-selection strategy, where they have fewer offspring but take more care of them to ensure that they are successful. The r-selection strategy is the opposite, where the species has more offspring but invests less in taking of them, while many might die some will be successful by chance. ",
"Every species has their own reproduction strategy. In modern times humans raise one or two kids, spend a lot of energy in raising it right. In the past they had lots of kids to aid in family labor in hunting, gathering or farming.\n\nA lobster might release a few thousand eggs and hope a thousand hatch, and maybe a hundred might live past larvae stage to juvenile, and one might reproduce in adulthood.\n\nIn good years, a few make it, in bad years none do. A lot of life depends on random events. This year the rains came early and there was a lot of food, next year a wild fire will burn or scare away all the food. Maybe the den gets infested with parasites and most die, coyote eats most the kittens, one manages to live because the coyote was full off the rest of the litter.\n\n Can't predict those things. ",
"To think of nature in logic and why is the kind of the wrong way to look at nature. Living thing in nature are a result of evolution so the reason that something is the way that is that was a successful way for that animal to develop in the condition it developed in. Thing are the way they are because of how history of the animal and its predecessors and the environment.\n\nThe result is what is the best way to spread the genes. If most of a litter die or like turtles only 1 in 1000 survive to adulthood it might be the best option giving the alternatives. Evolution does not care if there are many dead offspring as long as it is produce more living ones. Like the frogs in the question. Laying multiple eggs are a cheep for each egg so they can produce many. Most will not survive but som will. \n\n\nYou can still look at different spices have differens strategies for litter size for different animals. \n\nFor animals with litter sizes like cats and dogs it is likely that some of the dont reach adulthood. But if the only had one it would have a better chance of get feed but would still have a high risk of accidents or predators. So the way that result in the higher amount of living decedents is to have a large litter with some death but with more live one.\n\nLarger herbivores like horses, antilops etc often have only one offspring at the time. They survive by moving so that need highly developed offspring that soon can move along with heard. They protect the by a large group so the best way is to have one large offspring. ",
"The logic of nature is as follows. As long as there are enough children to give births to the next generation then the species is successful. Species that survives by having thousands of babies in the hope that 10% survive are still successful. Nature doesnt care about the percentage of survivors only that there are in fact survivors. ",
" > But on the other hand, it means that a lot of those babies will die a cruel early death (starvation, getting eaten, etc)\n\nNature doesn't really aspire to not be cruel. Survival strategies persist because they are effective. Many offspring that are born, with only a few that survive, but in so doing present a low burden to the mother, can be effective. Mom goes and makes more, and even though tons die, it doesn't matter because (fewer) tons live.\n\nFew offspring that represent a high burden to the mother, but survive relatively frequently (like humans), can also be effective. Mom's stuck raising you for years and years, but you stand good odds of growing up.\n\nEach strategy has evolved over time and is successful in its circumstance. ",
"There's some misunderstanding. Dogs and cats can actually take care of all those babies. They grow quickly and they have many nipples to nurse them all.\n\nAs for everything else, they aren't taking care of them at all. Most species of frogs don't sit around and babysit their young, and neither do most fish, arthropods, mollusks, or anything else. Their young are self sufficient from day one and they produce a lot of them so that some grow up.",
"Much of it has to do with the maturity process and the time it takes a an offspring to reach sexual maturity. \n\n\nIt's solely about perpetuating those specific cells. With animals with complex social systems or involved pathways to survival like humans or elephants they may spend more time with parents while they learn what it is to be a part of their species and also how to interact socially. Other animals May have relatively short maturity periods in which they quickly grow and learn how to be mature members of their species. \n\n\nIn the case of animals like frogs, they may experience absolutely no parenting and time to adapt and hatch immediately on their own and independent. There is also the interesting tidbit that many of these fill a niche on the food chain as they serve as a meal for so many other nearby animals. Having just one tadpoles will likely mean that generation won't reach maturity so they increase the odds with more offspring. \n\n\nRodents are slightly similar in that they act as prey for a large number of animals so the litter is increased. Likewise, their sexual maturity is reached relatively quickly, so that's less time that needs to be spent nurturing them. \n\n\nSome animals like dogs actually fall in between both extremes. They may have a large litter but they also have a pack that can aid in raising the offspring to maturity. Some risk not surviving but the resources in the packs territory will dictate the ultimate outcome. ",
"Many babies are \"precocial\". This means that fend for themselves at birth/hatching/metamorphosis. So a frog species has 10,000 eggs and 8,000 tadpoles metamorphose at the same time. There is no care for them. Get out there and eat. Survive if you can. Species like that are pantry for myriad predators though.\n\nRats OTOH have 8-16 babies and DO take care of all of them. The reason species like sheep or squirrels or doves have simultaneous birthing is to maximise survival. So many babies out and about at the same time, means predators are overwhelmed. Certainly a few will learn the ropes and survive.\n\nI hope this helps.",
"You've got it. They're not all meant to survive, there are so many of them because that means there's a greater chance of some surviving to adulthood. You'll notice that these are usually not the species that actually care for their young, so if youre not taking care of the children, some will die. If a lot of the children are dying, you need there to be a large amount of children so at least a few will luck their way into adulthood.",
"Nature doesn't operate by the same laws of morality as we do as humans.\n\nA reproductive strategy is good, by definition, if you end up with more of whatever is reproducing. A fish that releases thousands of eggs every mating season but only has 10 survive is still going to have more offspring to carry on its genes than if it raised 3 babies but cared for them all.\n \nIt may seem cruel to us, but we've evolved feelings of deep parental care and loving for our offspring *because* that's the reproductive strategy we evolved.\n\nAs for why some species evolved one or the other, the prevalent theory for a while was that pumping out tons of babies and hoping they survive is done when there's a ton of room in a specific niche a species occupies for the population to grow (called r-selection). The other strategy, where you have fewer babies and care for them (called k-selection), evolved when a population can't grow hugely because it's already at \"peak capacity.\" This theory apparently has been complicated quite a bit recently and isn't so neat as they made it out to be, but as far as I know it's still **broadly** true.\n\n",
"Nature does not care. It is neither cruel nor kind. Yes a frog will lay hundreds of eggs. Sea creatures will lay thousands.\n\nThere is no calculation in this. The DNA inside the cell has survived for millions of years. The mutations which produced the most offspring per generation persist.\n\nIt is always a good time to plug \"The Selfish Gene.\" which is a good book. But there are many others.\n\nEvolution does not use logic. It is only the simple persistence of favorable mutations and their concentration into individuals by sexual reproduction. Each individual can have favorable mutations from many ancestors. "
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1f6t40 | why does the volume on my stereo go from -80db up to 0db at full volume? | Based on the comparison chart here _URL_0_ I would think it would be around 100dB at full volume (i.e. very uncomfortable to be in the same room). | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1f6t40/why_does_the_volume_on_my_stereo_go_from_80db_up/ | {
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"Decibels (dB) are a logarithmic scale. A negative number means the signal is being attenuated. When log(Output / Input) is equal to 0, the input (the maximum volume possible) is equal to the output (what is actually coming out of the speakers).\n\nFor example, depending on the coefficient, half volume may be -3, which is equal to 10*log(1/2).\n\n-80, for example, using the same coefficient, would be 1 100 millionth of the full volume (basically nothing)",
"There's often confusion between attenuation of signal and actual sound-pressure level. When you say it should be around 100dB at full volume, you're thinking of SPL. When the scale says -80 to 0dB for full volume, it's describing the attenuation of the signal (probably the voltage). Full signal means 0dB, so -80dB would be fractions of millivolts of signal. \n\nSo you may be correct in saying at full volume your stereo would be 100dB SPL, but where would you measure the sound? 10 feet away? 100 feet away? What kind of room would you play it in? Would there be a natural resonance frequency which would sound louder?\n\nSPL has a lot of variables, so your stereo can't say it's playing at 100dB unless it's under controlled environment.\n\n[See here:](_URL_0_) (not trying to be condescending, just an easy way to copy a search)",
"There are a lot of different ways to describe this, and I'll take a shot at it. Your stereo at -80db is telling you that it can go 80db louder. When you get to 0db, you've maxed out the volume - and depending on the quality and configuration of your system, you are either rocking out or your speakers are smoking and about to catch on fire.\n\nBut anyways, 0db is also called \"unity gain\" which is the point where the volume of your input equals the volume of your output. Not your output to the speakers, but the output of sound to the amplifier circuit inside your stereo *after* the volume control. If your amplifier amplifies any input by 80db, you want to reduce the input to make the volume quieter. Hence, when it is silent, you are at -80db.\n\nThe reason all of this is necessary in the first place is because amplifiers are just fancy transformers that boost voltage at a constant ratio - with some capacitors to help smooth the demand for voltage when a sudden loud sound is fed into (and out of) the circuit. You need an attenuator (volume control knob) to lower the signal strength to the amplifier in order to lower the amplifier output to the speakers. \n\nHopefully that helps.\n\nEdit: Finished an incomplete thought",
"The decibel (dB) is a generic unit. It can be used for lots of stuff that can be measured with logarithms. In this case, the -80dB probably refers to a voltage gain (ratio of output voltage/input voltage), so if you increase it you get more \"power\" with the same input. The sound decibels are measured according to a reference sound pressure (again, some ratio, but this time it's measured pressure/reference pressure), and it's not related to the voltage gain directly. Those two dB units, although they have the same name, measure unrelated things. The stereo itself may not give accurate info about sound pressure dB's because that depends on a whole lot of stuff (including humidity, audio frequency, etc.)",
"I'm an acoustical engineer. There are a lot of answers in this thread that come *really* close to the correct answer, but don't quite get there.\n\nAs others have explained, the decibel is actually a unit of change. It expresses the ratio of two values. So we have the measured value, and then we use a reference value. With dB-SPL (Sound pressure level), we use 20 µPa, which is the lowest pressure change that a human ear can hear under ideal circumstances at 1,000 Hz.\n\nYour stereo has no idea what the sound pressure level that you're experiencing will be, because there are so many factors. There are multiple amplifiers, loudspeakers of different efficiencies, and then there is the acoustical environment. The stereo receiver does not know where you're standing in the room, which makes a tremendous difference.\n\nWhat the stereo receiver does know is its own maximum capability. For digital electronics we use a unit known as decibels-Full Scale (dBFS). dBFS uses a reference value of the maximum level that system can count to. So let's say it's a 16 bit system, as this is CD quality. That means that at that point in time, the stereo has counted to 2^16, and it literally can't count any higher. 2^16 + 1, is not an option. (Note: It's *slightly* more complicated than this, but this amount of information is sufficient to understand the concept.)\n\nThe maximum value (2^16 ), gives us a level of 0 dBFS. The easiest way to represent the current level that the system is outputting is to give a number of decibels *below* 0 dBFS. Hence, the negative dBFS values."
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au1c3m | what is differential privacy? how does it work and why is it important? | I hear the term differential privacy being used more and more among techies. What is it? Why is it important, and how does it work? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/au1c3m/eli5_what_is_differential_privacy_how_does_it/ | {
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"Differential privacy has to do with how confidential information can be gleaned from seemingly obfuscated (disguised) information. Organizations like the US Census Bureau and the Department of Labor collect a lot of data about people under the condition of anonymity. This data is then published in aggregate to inform the public as to the state of the country. Theoretically, it is possible to go through these tables and, repeatedly cross-referencing one data set to another, to find confidential information that was not explicitly published.\n\nFor instance, if you look up your local chamber of commerce information, it might give you last year's annual sales of goods by sector (food & beverage, hardware, gas, clothing, etc.). But if you also know that there is only 1 clothing store in town (or if this information is posted as part of the town directory), then even though the board did not explicitly tell you how much that clothing store sold last year, you can determine it from the information they gave.\n\nDifferential privacy is concerned with how to carefully curate how data is published to prevent this. For instance, the chamber of commerce may simply omit the clothing section from their economic report, or roll it into a miscellaneous goods section.\n\nGiven the enormous amount of data being collected and published every day on all different facets of people's lives, differential privacy is important to allow this data to be usable without compromising individual identities."
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6pt2gi | why is it called "cream of tartar" when it very obviously isn't creamy? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/6pt2gi/eli5why_is_it_called_cream_of_tartar_when_it_very/ | {
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"Cream of Tartar is the *nom de plume* of potassium bitartrate. I couldn't find the exact source of it's name, but I can theorize. One possibility is its color - cream - but the other possibility is related to another definition of the word \"cream\" itself.\n\n > To skim, or take off by skimming, as cream.\n\nIt's left as a residue in winemaking. It might be possible that the name comes from someone skimming it off the surface of the wine or cleaning it off the inside of the barrels.\n\nI'm not entirely sure. That's the best I can give you."
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1so8lr | what qualifies a planet as a planet? | A friend of mine and myself stumbled upon this question and we can't really seem to come to an agreement as to what a planet actually is. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1so8lr/eli5what_qualifies_a_planet_as_a_planet/ | {
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"They have to meet three criteria.\n\nThey have to be massive enough to pull themselves into a spherical shape.\n\nThey must orbit a star.\n\nAnd they need to dominate there orbit by mass. So most of the mass should be with the planet and not other debris that share its orbit.\n\nThe last rule is why they decided pluto is no longer a planet :(\n\nThese rules, at least as far as the astronomical community is what constitutes a planet, from a dwarf planet or other debris in space.",
"According to the International Astronomical Union, a 'planet' has the following characteristics.\n\n* It orbits a star (the Sun).\n* It is big enough that gravity makes it round.\n* It is the dominant object in its orbit.",
"The definition is essentially arbitrary - there's a spectrum from \"tiny rock in space\" to \"Earth\" to \"Jupiter\" to \"star\". But the definition currently used by professional astronomers is that it is (a) large enough to be pulled into a sphere shape by its own gravity, unlike potato-shaped asteroids; (b) not large enough to begin fusion and become a star; and (c) large enough in comparison to nearby objects to have cleared its orbit of any competitors except those orbiting it.\n\nFor examples of objects that fail these tests:\n\n- Many asteroids have unique orbits, but are not large enough to be rounded or clear their orbits.\n- Ceres, formerly the largest known asteroid and now classified as a \"dwarf planet\" alongside Pluto, Eris, and two others, is large enough to be spherical but hasn't cleared its orbit, which lies inside the asteroid belt. The same applies for Pluto, which orbits into an area filled with thousands of objects like it.\n- Red Dwarfs aren't too much bigger than planets in our solar system - perhaps 30 times the mass of Jupiter - but they're large enough to sustain fusion in their cores and are therefore stars and not planets.",
"The International Astronomical Union in 2006 set the definition of a planet in the Solar System as being something that:\n\n* is in orbit around the sun\n\n* has taken on a spherical shape\n\n* has \"cleared the neighborhood\" of its orbit, meaning it is the dominant gravitational force in its area\n\nA body that only meets the first two criteria, as in the case of Pluto, is classified as a dwarf planet."
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74czha | is there a limit to how much the brain can learn a new talent in a given time period? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/74czha/eli5_is_there_a_limit_to_how_much_the_brain_can/ | {
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"As we understand it, the brain primarily learns new skills by devoting neurons in the brain to certain knowledge, as well as developing pathways between neurons. As you might expect, this is a very complex process and there's a lot about the \"what neuron to what neuron in what part of the brain\" that we don't understand.\n\nDeveloping new skills is, likely, limited by the amount of neurons your brain can commit at any given time; it's been observed there's been a daily limit where your brain can only devote so much time to learning. Just like the rest of your body, your brain has a certain metabolism and speed at which it can work. As the main regulator of just about everything that goes on in your body, the brain is also suspectible to mood, health, diet, genetics, injury, education, etc. All of these factors can impact the speed and efficiency at which your brain can develop new neurons.\n\nJust like a strong muscle, a healthy and well-trained brain can learn amazing feats, but it has it's bodily limit."
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2gr9w3 | if i inhale a smell and exhale, will the exhaled air still have the smell?... | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2gr9w3/eli5_if_i_inhale_a_smell_and_exhale_will_the/ | {
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"Your exhaled air is pretty much the same air you inhaled, apart from a little more water and CO2 (18% on inhaled air vs 22% on exhaled air - estimates) so yeah, you still have particles that caused that odor when you exhale. Some of it may even adhere to your respiratory tract and keep your breath with that smell for some time (e.g. - smokers keep that cigarrette smell for some hours after smoking, even after bathing, changing clothes and brushing their teeth",
"Trying to cover up your farts? You're not alone in that one."
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1fnqtk | equity on a property. | I'm always seeing ads saying they can 'release equity' on your house. I get to keep the house (if I had one) but get some money that magically appears out of no where? Obviously not.
What's the catch? What *is* equity?
Also, why are these ads always targeted at OAPs? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1fnqtk/eli5_equity_on_a_property/ | {
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"Let's say you want to buy a home worth $100k. You only have $20k available, so you take a loan (a mortgage) for the remaining $80k. The equity you have in this home is the amount of money you would personally get if you sold it. If you sold this home for $100k, you would have to pay back the $80k mortgage, and you would personally get $20k, so that is your equity.\n\nNow imagine it's 10 years down the road. The price of the home has increased, and it is now worth $200k. At the same time, you have put in $10k worth of payments on your mortgage, so you only owe the bank $70k.\n\nIf you sold this home for $200k, you'd have to pay the bank $70k, and the remaining $130k would be yours. That's your equity.\n\nNow for a lot of people, that's an irresistible source of \"free\" cash, but the problem is you can't get it until you sell your house. So, what they do, is \"sell\" their house in the form of a mortgage. They take ANOTHER loan out on the house, and use the money from that loan as their free cash. This will drop their equity in the house, but the upside is they can buy cars, TVs, big vacations, pay for medical bills, whatever...all without actually selling their house.\n\nAs an example, your house is worth $200k now, and you owe $70k on your mortgage. You now take a second mortgage for $100k, which gets dropped into your bank account in cold, hard cash. Your house is now still worth $200k, but you owe $170k on the mortgage.\n\nMake sense?",
"Equity is, quite simply, the value of your house, minus the mortgage.\n\nFor example:\n\nYou buy a house for $200,000. You pay a $20,000 deposit, and use a $180,000 mortgage to pay the rest of the cost.\n\nAfter 20 years, the house is worth $350,000, and your mortgage is now $50,000.\n\nYou have $300,000 equity. This is the value of the house ($350,000) minus the mortgage ($50,000). If you sold your house today, this is the cash you would pocket (slightly simplified, ignoring any fees, etc).\n\nSo what is equity release? Well, it's all very well saying you have $300,000 equity in your house, but you can't use that equity, because it's tied up in your house. The only way you can use it is if you sell your house.\n\nThat's where equity release comes in. Equity release is a loan, similar to a mortgage. Like a mortgage, it's secured on your property. But it usually doesn't have to be repaid until you die.\n\nSo if you want to buy yourself that Ferrari you've wanted all your life, you could use equity release to borrow $100,000 - to release $100,000 of the equity in your house.\n\nIf you did that, and then died the next day, then your house would be sold, and $50,000 would be used to pay off the remainder of the mortgage. A further $100,000 (plus fees and interest, of course) would be used to pay off the equity release loan. This still leaves $200,000 equity in the house, which your family would benefit from.\n\n(And you wouldn't get to enjoy your Ferrari, because you'd be dead. But that's not really the point....)\n\nAs for why they're targeted at OAPs - young people don't have much equity in their property, because they haven't paid off much of their mortgage. And because they don't expect to die for many years, if they did use equity release, the amount of interest due by the time they died would be more than the equity in the house, so they wouldn't be able to repay the loan.",
"Equity is what your house is worth minus what you owe on it. If you owed $100,000 on your house and sold it for $300,000, you'd get $200,000 from the sale (because you're obligated to pay off the mortgage when you sell the house). So that $200,000 is your equity.\n\nWhat \"accessing equity\" really means is that a bank lends you money because they believe that you have enough equity to pay back the loan. Basically, in addition to checking your credit, they estimate what your house is worth and check how much you owe on it, and if they're satisfied, they'll lend you money under these conditions:\n\n1. If you sell the house, you have to pay back the loan at that point;\n2. If you fail to pay the loan, they can foreclose on your house—basically, take it from you and sell it to get their money back.\n\nThe catch? Well, this is not a \"catch\" strictly speaking, but hopefully now you understand that it's not free money that appears by magic—it's a **loan** and you have to pay it back with interest.\n\nThere's also risk to it, because your \"equity\" is always a **changing estimate**: you and your bank *think* your house is worth $300,000, but (a) you both could be wrong, and (b) the value of the house could change downwards.\n\nSo imagine you owe $100,000 on your house, you and the bank think it's worth $300,000, and they lend you $150,000 against your equity. Then you have to sell your house, but oops, nobody wants to pay any more than $225,000, and you owe the banks $250,000. Ooops."
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m6jjy | a franchise | I've never really understood it. I always thought companies like McDonalds & Starbucks were examples of franchises, compared to the local coffee shop down the road. But, then I hear people describing sports teams as 'a franchise'. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/m6jjy/eli5_a_franchise/ | {
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"A franchise is basically a pre-packaged business for sale. Take McDonalds as an example: some locations are owned by the head office, and others are owned indpendently. The independently owned ones purchase their uniforms, cups, napkins, etc. from head office; they have to follow the rules that head office says; but, they get free marketing and other benefits. The independent owner can make their own success by figuring out ways to run the business efficiently within the rules, without worrying about managing a lot of that stuff. \n\nI think the term \"franchise\" is used to refer to sports teams because each team is independently owned, but has to meet all the rules of the league. So, an NFL football team is like a franchise of the NFL, but it gets some independence in making up its own brand, choosing players and staff, etc.",
"So McDonalds might have 2,000 individual stores or \"franchises\" that make up the company. The NFL has 32 teams or \"franchises\" that make up the league. \n\nThey're individual pieces that make up the whole. ",
"A franchise is basically a pre-packaged business for sale. Take McDonalds as an example: some locations are owned by the head office, and others are owned indpendently. The independently owned ones purchase their uniforms, cups, napkins, etc. from head office; they have to follow the rules that head office says; but, they get free marketing and other benefits. The independent owner can make their own success by figuring out ways to run the business efficiently within the rules, without worrying about managing a lot of that stuff. \n\nI think the term \"franchise\" is used to refer to sports teams because each team is independently owned, but has to meet all the rules of the league. So, an NFL football team is like a franchise of the NFL, but it gets some independence in making up its own brand, choosing players and staff, etc.",
"So McDonalds might have 2,000 individual stores or \"franchises\" that make up the company. The NFL has 32 teams or \"franchises\" that make up the league. \n\nThey're individual pieces that make up the whole. "
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o8g8a | how do they make those gifs where everything is static except one thing? | I don't really know how to describe it, and I don't know what to search for so sorry if this has been asked.
Example:
_URL_0_
This is a bad example because clearly the whole right side is animated and not the left. But hopefully you get the idea, there are much more precise ones out there.
How do they isolate the moving part? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/o8g8a/how_do_they_make_those_gifs_where_everything_is/ | {
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"I think this link might be the explanation you are looking for. The type of GIFs you mention are also known as *cinemagraphs*.\n\n[How to create cinemagraphs by Lifehacker](_URL_0_)",
"I made [this one](_URL_0_) last week in Adobe After Effects.\n\n1. I shot the video of me juggling pears, using a Canon 7d at 1920x1080 (higher res is always the best)\n\n2. Brought the video into the timeline, found a start and stop point where my hands were nearly identical after two throws (of a pear), and decided that would be where I could loop it the best. I got lucky, because I didn't have to do any transition work for my hands, they were perfectly placed for looping. (if they weren't, I would've had to do some major augmentation of the video, which I'm not even sure of what I would've had to do.)\n\n3. Then I masked off everything that wasn't supposed to move. My face, the left (my left) part of the shirt, the entire background. This would be a footage layer for me to pick a background plate (still image, in this case).\n\n4. Built a background plate of the static image of me. This background plate didn't have my right arm (my right) in it. This allowed me to make another layer on top of the background plate, a layer that was *only* my right arm juggling.\n\n5. Rotoscoping (frame by frame masking). Fingers across the face, the pears in the mirror as well as in the foreground, my hand over my leg, etc.\n\n6. I faked a looping animation of one pear. You will see in the gif that every third throw (approx), one of the pears will sort of \"move\" to the left of the screen right at its zenith- this was me manipulating it so it would match the footage of the pear coming back down, creating the loop. I could've done this smoother, maybe.\n\n7. Then I uploaded it, added it to my demo reel. Then I put on Debussy's \"Clair de lune\" and had a beer.\n\nedit: formatted a lot. fixed grammar.\n\nAlso, the link you provided isn't a real cinemagraph, as it clearly does not loop seamlessly.",
"I'm not sure what you're asking of, but a gif is a bunch of still pictures played in sequence. \n\nYou can simply keep the static parts the same in every frame and only change what you want to have motion. ",
"Mask out the area you want to keep moving, put it over a still frame.",
"It's fairly simple if you're using photoshop: just import a loop of the video you want to do it on, duplicate a single frame of the things you want 'static', bring it up to the top of the layers and then delete or mask the layer where the animate objects are.",
"If you like these, be sure to check out [r/cinemagraphs](_URL_0_)!"
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cy34st | how to antitrust laws actually work to prevent monopolies? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/cy34st/eli5_how_to_antitrust_laws_actually_work_to/ | {
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"The government can bring companies and people to court if they do anything toward forming an illegal corporate trust. This ranges from trying to merge into a mega-company to corner the market (blatant) to secret collusion to inflate prices on their goods or services so they don't have to compete against each other with fair pricing (subtle). If the courts ultimately agree their actions constitute an illegal trust, the companies can lose their combined interests on top of civil penalties and individuals can face criminal penalties.",
"At least in America, antitrust laws are NOT designed to prevent monopoly, they are more designed (in theory) to prevent abuse of monopoly power. \n\nSo in the 1990's, the government case against Microsoft was not that they were a monopoly, per se. The issue was the accusation that they abused that monopoly power in the operating system market to unduly influence the browser market."
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1wm8ra | why isn't pop music from the 1920s or 1930s popular today? | If we're the same flesh and bones and people for the last 100+ years, why would the music that made people go crazy in the 20s, make most people change the station today?
This really relates to music from any previous decade, but certainly 60s and up, still has some influence today. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1wm8ra/eli5_why_isnt_pop_music_from_the_1920s_or_1930s/ | {
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"Culture. Liking certain types of music isn't ingrained in our genes or anything. ",
"This is something I've often thought about, because 95% of the music I listen to is from the 20s to the 50s. And what seems to be the case is that, had today's pop music been available in the 20s and 30s, it probably would have dominated. The nature of today's pop music makes it much more accessible to the casual listener than any type of music before it. And there are a few reasons for this.\n\nA) Generational shift: The vast majority of pop music consumers are younger generations (early teens - mid-20s). While this was also true back in the jazz era, it wasn't quite to the same extent. This is important in that a younger audience commits more time and money to their own interests rather than practical things such as job searching and the like.\n\nB) Repetition. Pop music today, more than ever before, is based on hooks and choruses that are easily remembered and often repeated throughout a song. Even within lyrical verses, there tends to be repitition of melodic, harmonic, and rhythmic patterns. And as much as we like to think we're advanced and sophisticated, we like an easy, repetitive snare on two and four just as much as the random dancing cats on YouTube (I don't have a link, but they're there somewhere). Additionally, many different pop tunes often employ [similar harmonic patterns](_URL_0_). Humans are naturally more comfortable with familiar, repetitive patterns, so these features of pop music greatly enhance their popularity.\n\nC) Availability. It goes without saying that thanks to YouTube and iTunes and the like, music is just more widely available. You don't have to actually get up and go anywhere to get it. And the more popular tunes get more exposure. So they get even more popular simply through their own social momentum.\n\nEDIT: I get that this might make me seem like I'm really old and bitter about the youth of today, but that's not true. I'm in my twenties, and think today's youth aren't really any better or worse than any other generation's youth.",
"Thinking about it from a logical standpoint, there are several things to consider.\n\n1 - There was really no such thing as youth identity in those days. It wouldn't really become a tangible thing until Elvis / Buddy Holly / etc. This means that:\n\n2 - There was, generally speaking, a narrower band of types of listeners music needed to appeal to in order to sell. \n\n3 - Radio was obviously a major source of entertainment in those days, and most popular music of the time was mainly utilized not just for straight up listening purposes, but mainly for dancing, which was a lot different from the way we dance today. Therefore, popular music at the time was written in such a way that you could dance to them, in the style of the time.\n\n4 - With the constant turning of the great wheel of time, brought changes. Much like genes mutating over many generations, so too has popular music. Up-tempo jazz eventually gave birth to Rock 'n' Roll, the influence of which is still felt in the vast majority of popular music today (with a measure of influence from hip hop, obviously). Whatever is popular now is directly and inexorably linked to that which came before. Previous, outmoded styles, are not forgotten; having been fully consumed and digested by the public, they are stigmatized as \"old\" and culturally less valuable the more they age (exceptions being interest in the concept of 'retro'), in favor of that which already shares a large portion of its 'genetic makeup' with what also made those old tunes great.\n\n5 - A more distant factor is the nature of the lo-fidelity of the recordings of the era. Musical recordings of the time not only lack the accurate frequency reproduction found in today's music but also recording techniques have evolved exponentially over time. Even the most professional bands of the era were prone to all kinds of human mistakes - phasing (one part of the band becomes slightly out of time with the rest of the band), intonation (playing traditional instruments) - and even the relatively low quality of recording media at the time practically guarantees that entropy has a marked effect on our perception of older music, however 'unfair' that might seem.\n\ntl;dr - they didn't have anything else to compare it to, and in spite of your hipster glasses, wax discs are an imperfect medium with which to store information accurately."
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b85quj | how does magnesium help to prevent cramps ? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/b85quj/eli5_how_does_magnesium_help_to_prevent_cramps/ | {
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"Magnesium is one of the ions that is used to conduct electrical signals through your muscles in order to contract them. A magnesium deficiency is theorized to predispose someone to cramps, which are an involuntary electrical discharge in your muscles causing involuntary contraction."
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n6ibf | how does a planet make noise? | What exactly am I hearing in this video?
_URL_0_
Is it an interpretation of the waves, or is the planet actually audible to the human ear? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/n6ibf/eli5_how_does_a_planet_make_noise/ | {
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"It's an interpretation of the magnetic field the planet has, audible sound can't travel through the vacuum of space but electromagnetic field are easy to detect with the right equipment. By assigning different parts of the field to different sounds you can have a roughly corresponding noise. Imagine each colour of the rainbow was a note and as you got to violet from red the noes got deeper, the same is applied to the field for the planet.",
"It's an interpretation of the magnetic field the planet has, audible sound can't travel through the vacuum of space but electromagnetic field are easy to detect with the right equipment. By assigning different parts of the field to different sounds you can have a roughly corresponding noise. Imagine each colour of the rainbow was a note and as you got to violet from red the noes got deeper, the same is applied to the field for the planet."
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4ouqaw | when you sweat a lot when you work out, what is that sticky white substance on your lips? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4ouqaw/eli5_when_you_sweat_a_lot_when_you_work_out_what/ | {
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"After re-reading the question I died laughing...\n\nThe white sticky substance is electrolyte, saliva, and mucus buildup. Dehydration causes these things to be thicker, causing the white stuff on your mouth lmao"
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6shqpk | america is the only country to have ever used nuclear weapons in combat. why is everyone concerned with making sure other countries don't have nuclear weapons yet america is exempt from this expectation? | I ask this because I recently found out the fact that America is the only country that has used nuclear in combat - just has not given it any thought before. Just to be clear, I'm against anyone having nuclear weapons. I don't think anything good can ever come from having them, there is no one I'd trust to have such powerful weapons. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/6shqpk/eli5_america_is_the_only_country_to_have_ever/ | {
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"The two atomic bombs the US dropped were the second and third nuclear devices ever detonated, there were no rules prohibiting their usage at that point and we really didn't know how devastating their usage would be at that time\n\nThe nuclear armed countries are concerned about non-nuclear countries becoming nuclear countries because all it takes is a crazy dictator with a couple of nukes to end the world. We came very very close to ending the world a few times during the cold war, its best if we don't invite anymore players to the nuclear game.",
"America, Russia, Japan, China, Isreal, and Several other countries have nuclear weapons at their disposal. The cold war was a nearly-catastrophic war that would have pitched USA's and Russias nuclear arms against each other in the gulf.\n\nWe are the only ones who have actually set them off, but many countries still have them.\n\nThe only country we are immediately concerned with having nuclear arms is North Korea, because those of us who have nuclear weapons are at peace, and North Korea is volatile and seen as a threat to safety should they obtain them.",
"There are two main reasons why nuclear non-proliferation is a global priority: 1.) nuclear weapons destabailize international relations, and 2.) the governments who want nuclear weapons nowadays are generally not responsible ones. \n\n\nRegarding point 1: There are rivalries between countries all over the world, but generally tensions just simmer between rivals for decades. At worst, there might be a shooting war of some sort. But when one country gets nuclear weapons the balance of power becomes dramatically shifted, and their rival(s) understandably want them too. This is why the Soviets rushed to build nuclear weapons in the 1940's after their main rival, the US, developed them. Moscow wanted to even the playing field, and they did, but the nuclear-armed tension that followed nearly resulted in a global atomic apocalypse on several occasions. A modern example can be seen in the Middle East. Iran has very poor relations with the Gulf Arab states, so a nuclear-armed Iran would motivate Saudi Arabia and its neighbors to develop their own nuclear bombs. These situations are bad because when staunch enemies each have such powerful weapons figuratively and literally aimed at one another it dramatically raises the stakes in terms of future armed conflict. This is what happened when longtime enemies Pakistan and India each developed nuclear weapons: an already tense and sometimes bloody rivalry permanently became much more dangerous. \n\n\nRegarding point 2: Generally speaking, the governments that actively pursue nuclear weapons are not the kind of governments that should be allowed to have them: North Korea, Iran, Saddam's Iraq (which had a large nuclear program in the 1980's,) etc. Pakistan's government, for example, developed nuclear weapons in the 1990s then allowed the secret export of nuclear material and expertise to other countries. Regardless of one's opinion on, say, US foreign policy or Iran's geopolitical ambitions, it is hard to see why the world would be any better off with an atomic Pyongyang regime or a country like Pakistan illegally selling enriched uranium on the global market. \n\n\nIt's also important to understand that the US is not the only country with nuclear weapons. France, the UK, Russia, Israel, China, Pakistan, India, and North Korea also have them (although Israel does not publicly admit it, and North Korea did so in defiance of global pressure.) The first countries to obtain nuclear arsenals (US, UK, USSR/Russia, France, and China) did so during the Cold War era and since that time have acted as the de facto \"nuclear club\" which has led global efforts to halt nuclear proliferation. Their genera rationale for doing so is \"we did it first, because we had to and it would be unreasonable for us to completely disarm, but nobody else should be allowed to join our informal club ever again because it would be bad for everyone worldwide.\" \n\n\nIt's also important to understand the following broad chain of events regarding the history of nuclear weapons:\n\n* World is embroiled in WW2. America develops the atomic bomb as the ultimate trump card against the Axis. -- > \n\n* Faced with a fanatical Japanese enemy that refuses to surrender, US decides to use new weapon against Japan rather than invade Japan which could kill millions. -- > \n\n* USSR and USA become rivals as WW2 ends. USSR is eager to even the playing field. -- > \n\n* USSR gets nuclear weapons -- > \n\n* While the USSR is working toward their own bombs, USA shares nuclear secrets with France and UK since they are close US allies against USSR. -- > \n\n* USSR and China shift from being allies to being rivals. China develops their own bombs as a counterweight to both Soviet and American nuclear arsenals. -- > \n\n* Israel, outnumbered by enemy Arab states on all sides, builds their own nuclear weapons in order to make their enemies more hesitant to attack. -- > \n\n* Iraq tries to develop nuclear weapons in order to level the playing field against Israel, but Israel takes direct military and espionage action against their nuclear program. Neither Iraq nor any other Arab nation ever attains nuclear capability, leaving the military advantage tipped indefinitely in Israel's favor. -- > \n\n* With the end of the Cold War, US and Russia agree to reduce the size of their nuclear arsenals but their is no serious talk of either side eliminating their nuclear capability altogether. -- > \n\n* North Korea, which has grown increasingly isolated and impoverished since the end of the Cold War, begins a nuclear program in the 1990's -- > \n\n* The international community unsuccessfully attempts to both force and persuade North Korea to abandon their nuclear ambitions. North Korea tests their first nuclear bomb in 2006. This makes an already tense decades-long confrontation on the Korean Penninsula even more serious. -- > \n\n* Iran accelerates their nuclear program. The Iranian government claims it is only for energy production but both the US and Iran's neighbors are highly concerned about the prospect that Iran might secretly develop nuclear weapons which would dramatically disrupt an already uneasy balance of regional influence between Iran and its neighbors. "
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1prrtw | is the reporting of al jazeera reputable? can you compare the reporting bias to other popular us news sources? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1prrtw/is_the_reporting_of_al_jazeera_reputable_can_you/ | {
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"anybody here? haha",
"Al Jazeera English is fine. It's very similar in quality and in coverage to the BBC. \n\nThe station does have a slight bias towards issues that are good for the Qatar government but thats more pronounced on the non-english network. "
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3vrsu9 | why can't opticians just use a machine to get your exact prescription? | Sometimes they do use a machine but to get a rough idea. They then proceed to refine the guess by the machine but surely its possible for a more precise measurement? Also they seem to only be able to estimate your current prescription from your current glasses instead of getting an exact figure why is that? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/3vrsu9/eli5_why_cant_opticians_just_use_a_machine_to_get/ | {
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"First off, opticians aren't trained to use the equipment to get your prescription based off what you can see (think the test where the doctor is asking if 1 or 2 is better), that would be an optometrist or ophthalmologist. Both of those are doctors, opticians aren't.\n\nAs for your question, the machine can get an accurate read on the shape of your eye, but not in how your brain interprets the information. As an example, the machine always says I need +.25 sphere by -.25 astigmatism. In reality my brain is able to cancel those out so I see better with nothing than with the \"prescription\" the machine says. ",
"You can usually get an exact prescription from an existing pair of glasses using a machine called a focimeter, or less commonly (and basically only ever in exam situations) by a process known as hand neutralisation. Opticians won't make up new specs based on focimetry because even though they may know exactly what has been supplied, there's no guarantee that's what was prescribed. \n\nThe machine which gives the rough prescription is called an autorefractor and its manual equivalent is a technique called retinoscopy, which both give a pretty accurate measurement of the prescription held by the eye. These tests are objective, so they don't account for your preference or natural focusing power. \n\nA true prescription can differ from a given rx for many reasons, the most common few are probably the ability of your eye to effectively do some of the work for itself (for some longsighted patients, known as latent hypermetropes), high levels of astigmatism (which often need to be reduced as they can make things look stretched and cause dizziness when fully corrected, particularly for part time wearers or contact lens users), and accounting for the change from the last worn prescription (large changes aren't always tolerable). There are a lot of other things to think about when issuing an optical rx, and the machine just can't account for them like a human can."
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5l3kpp | why is coffee so delicious when it is hot or cold but be so disgusting at room temperature. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5l3kpp/eli5_why_is_coffee_so_delicious_when_it_is_hot_or/ | {
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"I really think it's just a matter of personal preference, no particular scientific reason behind it.",
"You haven't acquired the taste. I knew a person who loved day old coffee that has been sitting out. ",
"It comes down to expectation and what your specific culture deems okay. We learn to like the beverage a certain way, and when it is different we find the change distasteful. \n\nSometimes the temperature of a drink changes across cultures too, if you need actual evidence of a similar instance. In the States we drink pop/soda/cola with ice and typically find it gross if the drink isn't chilled. But in Europe (at least France to my knowledge) they drink it at room temperature.\n\nTL;DR it is what you were told was tasty when you were growing up. If you grew up being told lukewarm coffee was tasty, that's how you would prefer it.",
"As a long-time Pacific Northwest coffee snob, what you're probably tasting is a low-quality bean/roast combination showing itself at room-temp. Cold Folgers (or Starbucks) indeed tastes bitter. Cold fresh-roast organic still tastes pretty decent. \"Third-wave\" product is a step up in quality. Much of this is due to bean quality-control.\n\nStumptown even rolled out a designated chilled product, which they sell for 5 bucks a bottle (ridiculous). ",
"To preface, I'm a specialty coffee roaster and as such I've read a fair amount about the chemistry of coffee and how it relates to taste and smell. The answer is likely a combination of two things. \n\nCoffee is chock full of organic acids. The main group being Chlorogenic Acids which make up about 7 percent of the bean. During roasting these acids either break down completely or are turned into quinic and caffeic acid. Once brewed these acids directly effect the astringency of a cup of coffee. The coffee in your cup continues to brew though, and quinic and caffeic acids react in your cup to increase the level of acidity you taste.\n\nTo be brief, the acidity you are tasting comes mainly from other acids within the bean whose levels are dependent many things which can happen at the farm level. These acids are malic and citric, which account mainly for any sour or sweet acidity you taste.\n\nI double checked and edited the above from this source: [Organic Acids](_URL_0_)\n\nThe second answer has to do with temperature and how it affects your perception of taste and smell.\n\nIf you look at [this graph](_URL_1_) and [this graph](_URL_2_figure/mmm00090/?report=objectonly) you can see that as temperature decreases the measured perception of bitterness from caffeine and sweetness from sucrose decrease while the perception of citric acid (as noted above a major player in the perception of acidity in coffee) remains relatively the same despite temperature. So as your cup of coffee loses temperature, you also lose the balance of sweet, bitter, and sour in your perception of taste and begin to taste mostly the sour citric and malic acids.\n\nAlso, much of what we describe as taste is smell. As stated in the article I will link below, \"Indeed, it is apparent in everyday experience that heating heightens the appreciation of odors sensed orthonasally; it would be very surprising if the same were not true of odors that originate in the mouth.\" So as your coffee cools, you begin to lose any flavors that your are perceiving through smell while simultaneously your perception of taste is becoming unbalanced to favor the sour acidic notes of citric and malic acid.\n\nSee here for a source on the second part: [Temperature and Perception](_URL_2_)\n\nI'm a little late so I'm not sure if anyone will see this, but I didn't see any other real answers at the time of me beginning to write."
]
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"https://www.ncbi.nlm.nih.gov/books/NBK236241/",
"https://www.ncbi.nlm.nih.gov/books/NBK236241/figure/mmm00090/?report=objectonly"
]
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||
48z2es | since the universe is estimated to be 13.82 billion years old, what happens when the hubble space telescope or james webb telescope sees something 13.82 billion light years away? | I just read an article stating that the Hubble Space Telescope set a new record for the furthest galaxy it has ever identified, GN-z11 which is 13.4 billion light years away. And since light travels one light-year in one year, that means that they are viewing the galaxy as it was 13.4 billion years ago (the math is a little tricky so you'll just have to trust me on that one).
That is relatively close to the beginning of the universe. What happens when they can see 13.82 billion light years away? Assuming that 13.82 billion years is an accurate estimate for the age of the universe. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/48z2es/eli5_since_the_universe_is_estimated_to_be_1382/ | {
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"Fun fact: even though the universe is only 13.8 billion years old, we can actually see about 46 billion light years away. This is because Space itself is constantly expanding, so even though the light from those parts of the universe are only traveling at the speed of light, the point that they come from is further away than when it started.\n\nBut to answer your question, what we see when we look as far as possible is a younger and younger universe. And when you look as far away as possible, what you see is [this](_URL_1_), the cosmic background radiation, which is in a sense the closest we can come to actually looking at the big bang. \n\n[This image might also help illistrate what I'm talking about](_URL_0_)"
]
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"https://en.wikipedia.org/wiki/Observable_universe#/media/File:Observable_universe_logarithmic_illustration.png",
"https://en.wikipedia.org/wiki/Cosmic_microwave_background#/media/File:Ilc_9yr_moll4096.png"
]
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52ur35 | how does my car sense tire pressure? | Does it have to do with the weight of the car, or is there an actual sensor INSIDE the tire?? Idgi. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/52ur35/eli5_how_does_my_car_sense_tire_pressure/ | {
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"Yes, there is a sensor inside the tyre. It is called the \"TPMS\", or \"Tyre Pressure Monitoring sensor\", [which looks like this](_URL_0_). They are a little battery-powered pressure sensor that lives inside the tyre and transmits the pressure numbers to sensors mounted on the car.",
"Tire pressure monitors fall into two categories: direct, and indirect. \n \nIn direct systems, a sensor installed in the wheel sends the tire pressure to the car's other computer(s) wirelessly. \n \nWhen a tire is deflated, it turns at a different speed. Indirect systems use the wheel speed sensors used for anti-lock braking to detect this difference."
]
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2whsdk | how come when you involuntarily blink you never notice, but when you realize and start blinking intentionally it's all you notice | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2whsdk/eli5_how_come_when_you_involuntarily_blink_you/ | {
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"Well... because you're thinking about it.\n\nSame thing with the nose, it's always there but your brain ignores it. Once you realize this then it is noticeable.",
"You just made everyone here blink intentionally you evil bastard now I can't stop realizing it "
]
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7pvzdu | we all know the mitochondria is the powerhouse of the cell. but how much power does it actually generate? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/7pvzdu/eli5_we_all_know_the_mitochondria_is_the/ | {
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"Out of the 36 ATP molecules (energy) made during aerobic respiration, 34 are made by the electron transport chain segment in the mitochondria. So in conclusion a lot of power.",
"This isn't a question that can really be answered. The Mitochondria produces the bulk of the \"fuel\" used to power reactions in your body, but it isn't like a power plant beaming relatively constant amounts of power to our homes down power lines.\n\nHowever we can do a _very_ __very__ rough approximation. ATP gives you approximately 7 kcal/mol. A kilocalorie is the same thing as the typical Calorie you see on food labels (1 food Calorie = 1,000 calories). A mole is just a specific count, 1 mole of ATP is approximately 600,000,000,000,000,000,000,000 molecules of ATP assuming I counted my 0's right. In scientific notation it would be approximately 6 x 10^23. A single human cell can produce, very approximately 10,000,000 ATP molecules per second. Lets just ignore ATP not produced outside the mitochondria, and say all of that came from that source. That means a single cell produces about 1.6x10^-17 moles of ATP per second, or to expand it out and risk another counting error: 0.000000000000000016 moles. At this level of approximation, 7 kcal/mol is about the same as 10 kcal/mol, so each cell produces very very approximately 1.6x10^-16 or 0.00000000000000016 kcal per second. With an average of maybe 15 mitochondria per cell, that would mean each mitochondria is responsible for about 0.00000000000000001 kcal / s from ATP. To put it in terms of Watts, that means the mitochondria has a power output of about 4 × 10^-14 or 0.00000000000004 watts.\n\nIt is highly likely I did something wrong somewhere in that calculation, and even if not some of my assumptions are probably off. In any case, the main point is just that each individual mitochondria is responsible for a very minuscule amount of energy production when compared to scales we are normally talking about with consumer goods. \n\nedit: But of course you have a lot of mitochondria in your body overall. A typical person has to consume 2000 kcal/day to produce the ATP needed by the body. ",
"but how many mitochondrias would i need to power a lightbulb?",
"1 glucose molecule produces ~28-36 molecules of ATP after it's gone through glycolysis, the Krebs cycle and the Electron Transport Chain [ETC]. Not exactly sure that that answers your question though since I'm not exactly sure what the answer you're looking for is though so..."
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rm5il | how can the quietest place on earth have a background noise in the negative decibels? | _URL_0_
Reading this article got me wondering. How are Decibels measured and how can one get into the negatives of sound levels? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/rm5il/eli5_how_can_the_quietest_place_on_earth_have_a/ | {
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"Decibels are a logarithmic unit. They take a ratio and output a value. One property of logarithms is that for ratios less than 1, the value of the expression is negative.\n\nThe \"loudness\" of a noise that is 0 dB is not in fact silent. It is an arbitrarily chosen reference point that doesn't actually relate to anything in nature. \"Silence\", or the complete absence of all sound, would in fact be negative infinity decibels.\n\nTherefore, negative decibel readings mean that the volume of the sound is less than our arbitrarily chosen reference point, not that it is somehow \"negative sound\". You should think of negative decibel sounds as extremely super incredibly quiet sounds, because what a decibel reading does isn't measure absolute volume but compare it to our reference point. Positive readings are louder than our \"standard sound level\" and negative readings are softer.",
"This is quite technical and hard to ELI5...\n\ndB measure the amount of pressure in a sound wave w.r.t. a reference pressure, but for now you can think of it as the same thing as measuring the size of the wave.\n\nLet's take a walk in the woods where we happen upon a lake. You toss a pebble in the lake and it makes a wave. We just decide to call the size of that wave 10 dB for now. Then you find a rock and toss it in. It makes a wave ten times as big! that wave is not 100 dB... but 20 dB!\n\nSo far so good, we go get uncle bob's tractor, drive it off a cliff into the lake and it makes a wave 1000 times as big as the rock did! but now that's only 50dB on our scale... Do you see that when I add ten decibels, the wave gets ten times bigger? That means the decibel scale is logarithmic; every time you add 1, you are actually multiplying the measured amount by something (specifically 10^1/10 in this case).\n\nSooo... how do we get negative decibels? Well. We go and find a leaf and drop that in a very still part of the lake; it makes a ripple; one tenth the size of the pebble's... that's zero decibels, almost there. We pluck a hair off our head, and gently poke the still water, and that makes a ripple one tenth size of the leaf's... -10 dB! Success!\n\nNow less ELI5:\n\ndB is a RELATIVE scale. You must set a reference point that will be equal to zero dB on your scale. In the acoustic use of the decibel scale, this reference *sound pressure* is 20 micropascals or μPa. It was chosen to be roughly the quietest sound a human can discern. So if 0dB is 20 μPa, when you see 100 dB you're actually talking about 200 kilopascals. That's a HUGE scale! 200 kPa = 200 000 000 000 μPa.\n\nOk, we set our reference point, now what is -10dB? it's just the pressure at 0dB divided by 10, or 2 μPa.\n\nMore Info:\n\nOn many audio devices there is a sound level meter that counts from negative infinity dB up to 0 dB and on to +12 dB or so. This is the sound level *relative to* the amplifier's clip level. If you're a sound engineer you spend alot of time tweaking stuff so that level NEVER goes over 0dB. You might realize that dB of an electric signal doesn't actually have anything to do with sound pressure, but actually has to do with voltage instead. That gets converted into sound pressure waves later on by the speakers.\n\n[Decibels](_URL_0_) are used in many other applications, and don't necessarily have to be associated with waves. It's just important to understand that there is a reference point, and from there onwards when you add ten, multiply the thing you're measuring by 10, and when you subtract 10, divide the thing you're measuring by 10.",
"Perhaps slightly more ELI5-ish:\n\nYou can have decibels in the negative, in exactly the same way that you can have temperatures in the negative. The point we mark as \"zero\" doesn't refer to the *complete absence of* sound (or temperature); it's just an arbitrary mark on the scale.\n\n(The parallel isn't perfect, of course: for temperature there's an \"absolute zero\", and that works in a way that doesn't work for loudness. But the analogy will get you a fair way anyway.)",
"It's essentially the same way temperature can be negative, it doesn't mean we have negative heat. It means its lower than our arbitrarily defined zero point."
]
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9z6ize | why do professional basketball players not use the backboard more on their shots? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/9z6ize/eli5_why_do_professional_basketball_players_not/ | {
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"You're taught when you first learn to shoot at the rectangle because the concept is easier to grasp. Overtime, you build muscle memory and having an accurate and higher arc increases the possibility for a basket. You wouldn't have to worry so much about the bounce or spin of the ball - less room for error.",
"That makes sense! Thank you. "
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efvuxj | why to trees cast weird crescent like shadows during a solar eclipse? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/efvuxj/eli5_why_to_trees_cast_weird_crescent_like/ | {
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"I believe the leaves become pinhole cameras and cast an image of the eclipse onto the ground.\nEdit: spelling of image and believe."
]
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||
6llc73 | how do craigslist scams work? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/6llc73/eli5_how_do_craigslist_scams_work/ | {
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"They send you a fake check, per various laws, the bank must give you the money in your account before the check clears. Most people think that the money showing up in the account means it cleared, that's not true, you don't really know for about 2-3 weeks, and it can be even longer. The scammers tell you that 3 days is enough.\n\nThey either overpay and ask for some cash back, or just take the item your selling. A few weeks later it bounces and the bank takes all the money back, you're left with minus any cash you gave them, and without whatever item you were selling.",
"besides the check scam mentioned, a scam I saw A LOT of while looking for an apartment is targeted at foreign applicants:\n\nThey post a beautiful and underpriced apartment with little info, and when you ask for more info/if its available, they say \"yes Its available! just send first/last/security to reserve it!\"\n\nWhen you ask to actually SEE the apartment first they go dark. \n\nThey hope people send in 3k+ as a deposit that youll never see again, claiming they are a real estate agent. \n\nALWAYS MEET THEM IN PERSON FIRST\n",
"This scam works in one of three ways:\n\n1) Asset theft - They give you a fake payment and you give them the item in return. It takes the bank a few days/weeks to realize the payment is fake and you are surprised when it bounces. This relies on you not understanding just how long a bank can reverse a deposit for.\n\n2) Cash theft - They give you a fake payment but \"over pay\". Say you agreed to 200 bucks and they give you a payment for 300. No problem, they say, just give me the extra 100 back in cash when i get the item. And you give them real money and the item, and then find out days or weeks later that you got fake money.\n\n3) Cash Theft part 2 - They give you the money and then \"change their mind\" and ask you to send the money back to them. Fake money goes into your account, but real money comes out when you refund their money. "
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1xccxe | why do major contests require participants/winners to answer mathematical skill testing questions? | I just saw this with a contest dealing with the Sochi Olympics; what does it exactly accomplish? Shouldn't the winner keep the prize no matter what? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1xccxe/eli5_why_do_major_contests_require/ | {
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"They legally turn the contest from a game of chance (often highly regulated by gambling laws) into a game of skill (not gambling). \n\nFun fact: Pinball used to be treated as a game of chance in many locations and regulated as gambling (it used to be common for people to rack up \"free games\" that could be traded in for items of monetary value or cash). This largely ended in 1976 when a man named Roger Sharpe, a witness for the American Amusement and Music Operators Association, who was testifying that pinball was a game of skill in order to challenge the NYC pinball ban, played a pinball machine to demonstrate. He called out what he was going for - and managed to make the shot. The committee voted to overturn the ban.\n\nHe admitted later it was pure luck that he made that shot."
]
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|
3wg9p7 | what is the difference, if any, between highway miles and non highway miles when buying a used car. | Does it really make a difference how the miles were accrued, or am I under some false assumption that a mile is mile. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/3wg9p7/eli5_what_is_the_difference_if_any_between/ | {
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"Highway miles are generally less stressful on cars than city miles.\n\n1 highway mile: cruisng at nearly constant speed, no braking, no accelerating, very little turns, smooth road for suspension, no shifting transmission, engine at 2-3k rmp\n\n1 city mile: stopping, accelerating a lot, turning, bumpy road, several gear shifts, engine from 1k-5k rpm.\n\nCity miles are just rougher on a car in general."
]
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|
2y4ft3 | i can't stand the heat of a jalapeno (2.500–8.000 scoville) but i can eat madame jeanette peppers (100.000–350.000 scoville) without any trouble. how is this possible? | I suspect the placebo effect, but I'm not completely sure. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2y4ft3/eli5i_cant_stand_the_heat_of_a_jalapeno_25008000/ | {
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"The scoville heat rating system is completely arbitrary and unscientific. Ratings are based on the sensitivity of the testers pallette and therefore are completely subjective since the sample size of scoville testers is relatively small. \n\n\"Unlike methods based on high-performance liquid chromatography, the Scoville scale is an empirical measurement dependent on the capsaicin sensitivity of testers and so is not a precise or accurate method to measure capsaicinoid concentration.\" - [Wikipedia](_URL_1_)\n\n\n**[High-performance liquid chromatography](_URL_0_)** is an analytical way of deducing how much of certain chemicals are in a mixture or substabnce.\n\n\nThat being said, Jalapenos contain less capsaicin than Madame Jeanette peppers, but it'd depend on the specific type of Jalapenos and the conditions on how you eat them.",
"Are you talking about raw Jalapenos or pickled ones? The sliced type you see people adding as toppings or mixed in with things are often pickled. A lot of tex-mex recipes call for pickled jalapenos as well. If that is what you are thinking about as \"jalapenos\" it may not be the heat that is bothering you but the acidity from soaking it in vinegar. ",
"Because it may not be the raw capsaicin, the flavorless oil which is the source of heat, that is causing your problem. \n\nMany factors determine how the oils react with your tongue. You could have a sensitivity to one of the phenol compounds found in Jalapeno flesh, but not in the other pepper, for example which would translate to discomfort when they are consumed. ",
"That's not enough information to answer. 2 peppers of the same kind can have absolutely different heat. Best I can do is provide a list of some factors that could affect heat in a pepper.\n\n- Brine reduces heat, as well as vinegar and salt. (So pickled VS fresh are vastly different).\n- Removing seeds and pulp reduces heat.\n- Age of the pepper when harvested (Older = spicier).\n- Age of the pepper after being harvested.\n- Air Moisture and temperature since harvest.\n- Soil acidity.\n- Soil Nutrients.\n- Amount of sunlight."
]
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"http://en.wikipedia.org/wiki/Scoville_scale"
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3iiuj7 | this is kinda a fucked up question, but why was there no blood in the video of the shooting? | [deleted] | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/3iiuj7/eli5_this_is_kinda_a_fucked_up_question_but_why/ | {
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"Hollywood and video games haven't been honest to you.\n\nPeople are not, in fact, blood filled balloons ready to start squirting everywhere.",
"- 1: Poor camera quality.\n- 2: Gun shots will be obscured by clothes and it will take time for blood to _seep_ through.\n- 3: People don't gush blood in squirts when hit by a bullet unless you hit a major external artery. ",
"Compared to films and games, blood leaves the body quite slowly (unless an artery is hit) and as bodies aren't highly pressurised we don't burst if ruptured. The bodies will leave pools of blood however, but lots will be absorbed into clothes etc beforehand"
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2zpqwd | victoria from reddit | I've seen a few AMA's that say "Victoria from Reddit is helping me out today", but who is he/she? What do they do? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2zpqwd/eli5_victoria_from_reddit/ | {
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"She works as the director of communications for reddit. During AMA's where you see that the person is usually on the phone with her and she types out their answers. Either because they aren't good with reddit/computers or are too busy to sit for a while and just answer questions, they can just talk on the phone and still go about their day, heres an ama with Victoria herself.\n\n_URL_0_"
]
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"https://www.reddit.com/r/IAmA/comments/2fgsv2/i_am_victoria_from_reddit_amaa"
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|
53g7ru | why are samsung note 7s exploding? how safe are my nexus and other phones? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/53g7ru/eli5_why_are_samsung_note_7s_exploding_how_safe/ | {
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"There's not an exact reason why Galaxy Note 7 batteries are exploding yet, but there are some preliminary reports that say there was a flaw in the manufacturing process that created a defect in the batteries for the phone.\n\nEssentially, this flaw put pressure on plates within the battery, which made the positive and negative poles touch. This, in turn, creates excessive heat to the point where the batteries can catch fire. That's what early reports from Samsung's investigation say, but the company is going to keep investigating to be sure of the exact cause.\n\nYou don't really have to worry too much in other phones - the batteries were made by a Samsung subsidiary for the Note 7 specifically, so no other phones will be affected by this flaw. If there were phones that were affected by a similar issue, you'd see global recalls for those too. \n\nJust in general, you don't typically have to worry about lithium-ion batteries exploding or catching fire. Most lithium-ion batteries these days come with protection circuits that protect them from overcharging and overdischarging. However, it's important to keep in mind that these batteries can degrade through normal use, so you'll want to swap out lithium-ion batteries regularly (once every two or three years seems to be pretty good in my experience)."
]
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[]
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||
59lzzk | what in a witty person's mind makes him/her so fast about coming up with a clever comment upon seeing something strange, while a "normal" person just stare, think or something else? | [deleted] | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/59lzzk/eli5_what_in_a_witty_persons_mind_makes_himher_so/ | {
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"As weird as it sounds: practice.\n\nMy SO used to only be able to sit and stare when I made a witty remark. After 5 years of dating and constantly slinging commentary, she can actually throw it back, and she's getting better.",
"Practice.\n\nA witty person keeps their mind sharp by utilizing it often, which helps maintain that quick response time and cutting cleverness.\n\nThey might have started out saying things in response quickly that weren't particularly clever, and learned to make more poignant responses over time. Or they might have started thinking about it more and having a clever response, but ended up being too slow in their delivery, so learned over time to quicken their mental processing so they get that opportunity to respond.\n\nBut it typically comes from practice, even the people who are seemingly \"naturals\" at it."
]
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[],
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2dus1c | what is the likelihood of two people being able to resurrect the human species from extinction(a new adam and eve ). | So with a gene pool of two what is the viability of a human population under ideal conditions vs non ideal so African and mestizo vs brother and sister.I ask because under my understanding of mendelian genetics (spoiler)the kids at the end of snowpiecer are doomed to raise one or two generation before inbreeding makes the population untenable. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2dus1c/eli5what_is_the_likelihood_of_two_people_being/ | {
"a_id": [
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"Which is why there never were an Adam and Eve. Either way, incest is impossible to avoid after the second generation and inbreeding is inevitable. This wouldn't make it impossible per se for only one man and one woman to restart the species, just incredibly unlikely.\n\nThe suggested minimum number for humans is 80 men and 80 women. There's more on the whys of that [here](_URL_0_). \n\n"
]
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[
"http://genetics.thetech.org/ask/ask113"
]
] |
|
616cov | if the government is there represent and protect the rights of citizens that elected it. why did the senate vote to allow isp's to sell your internet history? how does this benefit the citizens? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/616cov/eli5_if_the_government_is_there_represent_and/ | {
"a_id": [
"dfc33iu"
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"The government is there to represent and protect the rights of the wealthy individuals and large corporations that funded the campaigns full of lies that conned the citizens into electing it. \n\nThere, I fixed it for you. You should be able to take it from here."
]
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[]
] |
||
342som | whats causes ones hair to thin out? is it preventable or just genetics? | I am a 22 year old male and have started to notice that my hair is starting to thin out (seeing more hair land on my sink after i get out of the shower etc.) I have heard that genetics plays a role, I have also heard something about over-shampooing/conditioning might contribute to it, and pretty much all sorts of things but Ive never found a clear answer.
what actually causes hair to thin out? and are there any steps I can take to slow down, or hopefully stop this process? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/342som/eli5_whats_causes_ones_hair_to_thin_out_is_it/ | {
"a_id": [
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"Genetics plays a role. Environmental causes may exist as well, such as certain shampoos, etc., and stress is a factor as well. But anyone who tells you they know for sure what causes it is lying or misinformed. There are plenty of snake oil salesmen who will try to sell you different remedies, from gels to creams to vibrating combs, but really the only thing I would trust to maybe keep your hair on is propecia. I decided not to take it myself for fear of possible side effects but you can research that yourself. "
]
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[]
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|
9tfr74 | how does type 1 diabetes develop later in life? | I have a friend (19/yo F) who recently found out she has Type 1 diabetes after going into shock and being hospitalized. She told me the doctors said she had probably had it for a least a year, and that it was "dormant". I always thought that Type 1 was something you were born with and Type 2 was something thst develops in adults. A Google search could really only tell me that Type 1 can sometimes develop in people over 30. How? Is this normal for a 19 year old? What is it that can cause the body to just stop producing insulin? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/9tfr74/eli5_how_does_type_1_diabetes_develop_later_in/ | {
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"Type 1 is an autoimmune condition. Essentially your body's own immune system destroys the cells that create insulin (pancreatic beta islet cells). There can be a genetic link and this typically develops early in life, although theoretically could occur at any time as it can be just a random chance that the cells that attack the pancreatic cells are produced by the immune system. It typically presents in childhood or adolescence, and as the cells are broken down over time it can be several years before symptoms become noticeable. In worst case scenarios, and not uncommonly, you don't realise what is happening until you go into a state known as diabetic ketoacidosis (DKA), a life threatening but very treatable state. This happens when your body can't use glucose for energy any more, as it needs insulin for this, so it breaks down fat into ketones instead, which have the side effect of making your blood too acidic. If your friend was hospitalised, this is likely what happened to them. Type 1 diabetes is managed by insulin injections, to replace the insulin that is no longer produced.\n\nType 2 diabetes usually occurs later in life. It is insulin insensitivity rather than insufficiency. More common in older, overweight people, your body just becomes desensitised to the effects of insulin so it has a lower effect. DKA is less likely, as there is usually some insulin there which does enough to help you use some of the glucose, but not enough to deal with all of it. Type 2 is managed with diet and medications to lower blood sugar and increase the effects of insulin. In more severe cases insulin can be used as well.\n\nThese are the classic diabetes categories. They are also known as insulin dependent and insulin independent. In reality, there can be some overlap between the two \n\nEdit: added section on type 2 diabetes ",
"So they don't know exactly what causes type 1 diabetes, it just usually presents in children or preteens, but that's not a hard rule, just when symptoms tend to start popping up.\n\nWhat's happening in your body is your immune system is attacking your islet cells in your pancreas, which produce natural insulin.\n\nThere's some thought that someone living a very healthy and active lifestyle and a good diet might not present symptoms as severely, and it may just go unnoticed for longer than someone who isn't as healthy.\n",
"I’m not an expert by any means, but I was diagnosed as type 1 at 26 years old. It is an autoimmune disease and can happen at any time, though most manifest before age 30, I believe. It is believed that there may be environmental triggers that set off the immune system and tell it to attack the insulin producing cell. It is my understanding that a person does not develop symptoms of type 1 until 90-ish% of the insulin producing cells are destroyed. So yes, it probably was in the works for a while before your friend got “sick”. "
]
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oao6r | the controversy over smart meters | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/oao6r/eli5_the_controversy_over_smart_meters/ | {
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"Context? What is a \"smart meter\", and where is this controversy based out of? Who is involved?\n\nThanks!",
"Smart meters emit radio waves.\n\nPeople 'know' radio waves exist.\n\nPeople 'know' some powerful waves can harm people.\n\nThat being said, they're ignorant, and are trying to either be part of a conspiracy or a class action lawsuit."
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4i21kp | saudi arabia and india cover roughly the same latitude -- so why is one mostly sand, while the other gets plenty of rain? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4i21kp/eli5_saudi_arabia_and_india_cover_roughly_the/ | {
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"Well India is very mountainous and temperate which is much better for rain. Saudi Arabia is fairly flat and doesn't get a whole lot of protection or precipitation.",
"Ultimately, the answer is the Himalayas. They're big. Really, really big. So water vapor in the air compresses against them and produces lots of rain, because very little water vapor ever gets past them. The Arabian peninsula has some elevated areas, but nothing really to speak of. They get some precipitation, sure, but India (and the surrounding lower Asian countries) have got a particular geographical scenario that is a bit similar to a bathroom with no vent or window, if you keep showering in there, it'll always be humid in that room, because the humidity can't go anywhere."
]
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[],
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5bi77m | why some uk traffic lines are in zigzag? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5bi77m/eli5_why_some_uk_traffic_lines_are_in_zigzag/ | {
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"text": [
"The zig zags are before and after pedestrian crossings, indicating that you can't stop there (unless of course you're stopping for pedestrians). Yellow zig zags are also used to indicate no-stopping zones outside schools."
]
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[]
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||
8pet2v | why is it acceptable for smokers to take additional breaks at work? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/8pet2v/eli5_why_is_it_acceptable_for_smokers_to_take/ | {
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"Non smokers in my work place are allowed to take 5 min breaks twice a day same as the smokers",
"It's not acceptable at every workplace and some workplaces don't allow any \"smoke\" breaks outside of the regular legally required breaks. \n\nSo it really depends on the employer, the job, and the location. \n\nBut those companies that do, it generally is a holdover from when most people did smoke and a lot of times people and managers don't realize how big the inequality is between the smokers worktime and the non\\-smoker's work time. ",
"It isnt! I found out that as a non-smoker, if you start hanging out with the smokers during their \"breaks\", it will cast a negative light on their excessive breaks and bring about enforcement of established times for said breaks. It should be just as acceptable for a non-smoker to take 10 minute breaks every hour as it is for a smoker. If management has a problem with you as a non-smoker taking these breaks, you have a case for discrimination. A person's habit should not make them above company or workplace policy.",
"I've always taken a break when I feel like I'm getting frustrated regardless of if I'm going to smoke or not. I've also always been more efficient at my jobs than others so my employers have never had a problem with it. Maybe looking up to check on people taking breaks is detracting from your work. Get a task done and take a break!",
"I agree and would add that \"timed break\" should only be necessary in jobs where its critical to be available and working at all times (which kinda sucks) like being a cashier or a phone operator or maybe an assembly line worker or a bus driver.\n\nIf the job is not that mechanical you should take as many breaks as you like, whether to smoke or just to look at the trees and get some fresh air, as long as you get the job done or maybe even if you *can't* get the task done: the break will help you focus.",
"They only call them \"smoke breaks\" because smokers *need* to smoke frequently. There is nothing to stop you from taking a break to get some fresh air or take a minute to relax. Also, by virtue of not being addicted to cigarettes, it's not likely you would take nearly as many breaks anyway. Management won't stop you. Breaks aren't only for smokers."
]
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6pgp6w | in cases such as the murder of dylan redwine when it seems like there could be no possible reasonable doubt regarding the murderer, why does it still take so long for someone to be arrested and charged? | [Dylan Redwine](_URL_0_) was murdered back in 2012, and his father was always a suspect. K9's were able to detect cadaver scent in his father's house and pick-up. Dylan's blood was also detected in his house in various places including the father's clothes. The father had also made multiple threats about killing the kids before he'd let his ex-wife take him... yet he was only just arrested this year. Why did it take 5 years? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/6pgp6w/eli5_in_cases_such_as_the_murder_of_dylan_redwine/ | {
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"I'm not familiar with the case, but as a former defense attorney, I can tell you that the evidence you've listed is probably not nearly enough for the prosecution to secure a conviction. \n\nAs you mentioned, people can only be convicted of a crime if the state has enough evidence to show beyond a reasonable doubt that the accused committed each element of that crime. All crime (I'm simplifying) are comprised of two elements: an action, and an intention. \n\nSo, if you want to show murder, for example, you have to have evidence that shows the accused killed, and the accused intended to kill. \n\nThe evidence you've listed doesn't show that. Why? Look at each piece. \n**Cadaver dog scent.** Ignoring the possibility the dog is poorly trained, poorly handled, or picked up a non-human scent, whose scent was it? \n**Dylan's blood in the house.** Children bleed. Parents bleed. You have traces blood in your house right now. That doesn't mean you murdered anyone. \n**Threats.** Words are not actions. Did the father act on those words? How do you know? \n\nEven assuming all the evidence you listed is true, and the child died at the home, how do you know the death resulted from the father's actions? Did the child die accidentally? Did the father panic and take the body somewhere? \n\nThe situation you described seem similar to the Casey Anthony case. The child is dead. The child likely died in the mother's home. But that doesn't prove intent or action. \n\nGoing further, let's assume the father did kill his son, or that Anthony did kill her child. That doesn't mean you can get a conviction. To get a conviction the state has to show the evidence. Even if the father murdered 1,000 people, if there's no evidence, he's not guilty. \n\nAnd this is exactly why people acquitted of a crime are declared \"not guilty\" instead of \"innocent.\" Guilt is a legal standard. When the state doesn't have the evidence, you're not guilty even if you actually did it. It's not your burden to show you're innocent. It's the state's burden to show you're guilty. ",
"You only get one chance to convict someone. If you don't present a strong enough case and they walk, that's it, you are done. You do not get a chance to retry them. Even if you find amazing new evidence and conclusively proves they did it, once someone has been found not guilty, you cannot try them again.\n\nIn this case, the issue was primarily with the missing skull. The bones previously found could prove Dylan died, but they couldn't prove *how* he died. That becomes an issue because without a cause of death, it becomes a lot harder to prove beyond a reasonable doubt that this man killed this boy. Without that skull, it becomes a lot easier for the defence to argue that Dylan died because of an accident (one his father might not even have been involved in) and that all his father was guilty of is improper disposal of a body. And one juror having reasonable doubt is all it takes to allow this man to walk.\n\nSo they made a choice to bide their time and keep looking for the one piece of evidence that could conclusively prove his involvement (the skull). And sadly real life is not like TV where every forensic test gives you answers within an episode. In reality, many forensic tests take quite a time to complete, especially when they are in the back of a queue or have to be send away to other places (DNA tests can take up to six months). It all adds time, and yes it is frustrating, but better to take the time needed and actually nail the bastard than to try and rush it and have him walk because they couldn't erase the doubt in one juror's mind that yeah, maybe it had been an accident. "
]
} | [] | [
"http://www.thedenverchannel.com/news/crime/indictment-in-dylan-redwines-murder-case-details-gruesome-evidence-found-in-fathers-home"
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[],
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jj0v7 | why do i still smell like alcohol the next day? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/jj0v7/eli5_why_do_i_still_smell_like_alcohol_the_next/ | {
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"Your body breaks down most of the alcohol you drink in your liver, but a certain amount is breathed out and sweated out unchanged-- this is what makes you smell like booze!",
"Your body breaks down most of the alcohol you drink in your liver, but a certain amount is breathed out and sweated out unchanged-- this is what makes you smell like booze!"
]
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2mbg5v | what is the bottom hole in a wall plug and why is not used all the time? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2mbg5v/eli5what_is_the_bottom_hole_in_a_wall_plug_and/ | {
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"That is Earth Ground.. to prevent shock/death. Depending on the appliance being plugged in, it may or may not need it. If it has a motor of any kind..needs a ground post on the plug!",
"It's the safety ground. The current that actually does the work runs between the two blade-shaped holes, so the safety ground isn't actually needed when everything is working correctly.\n\nHowever, any device that has metal parts that aren't part of the circuit, e.g. a metal case, has the risk that a \"hot\" wire could short to the case, and then anyone who touches the case could be electrocuted. So, there's a third hole for a ground connection, and the case is connected to the ground. (The third hole literally connects to a big metal spike driven into the ground outside your house.)\n\nThis helps in two ways: one, it keeps the case at a safe (low/zero) voltage. Two, it keeps the case from being *silently* electrified and just lying in wait for someone to touch it. Instead, the short-circuit current flows to ground, hopefully blowing a fuse or breaker and disconnecting the whole malfunctioning thing from power.\n\nELI12 addendum: In the years since you asked the ELI5 version you may have learned that one of the two blade-type holes (the neutral wire) is *also* connected to earth ground, and supposedly acts the same as the ground. But there are a lot of ways that things can (and do) go wrong that make it worthwhile to have a separate, dedicated wire for the safety ground. Also, it's really common for outlets to be wired up backwards so their hot and neutral wires are swapped, so you can't really rely on the neutral being the one it's supposed to be.\n\n",
"Perhaps a practical explanation helps:\n\nSuppose you have an electric refrigerator that has a steel exterior, but is mounted on rubber wheels.\n\nAnd also suppose that the insulation on an electrical cable near the exterior becomes frayed and energizes the steel exterior.\n\nWithout the ground plug the refrigerator stays energized, and the exterior shocks anyone who walks up and touches it because the electricity travels to the ground through the person. (It's insulated from the ground until the person's body completes the circuit.)\n\nWith the ground plug, that does not happen.\n\nThe ground plug is used to connect the frame of the refrigerator to the ground rod driven in the ground near the electric meter through the breaker panel.\n\nIf the frame of the refrigerator were to become energized the breaker should immediately flip the circuit off and prevent anyone from being shocked.\n\nThis same principle works regardless of the nature of the item plugged in. The ground plug always connects to the frame of the device.\n\nOlder homes in the US do not have such a ground wire system so the outlets only have 2 prongs."
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2udmwf | when a cat has a litter of kittens, why is it that they are not identical like when a human female has twins? | Edit: I know that human twins are not always identical. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2udmwf/eli5_when_a_cat_has_a_litter_of_kittens_why_is_it/ | {
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"When cats go in heat they release multiple eggs. These multiple eggs can be fertilised by the sperm of one male cat (usually what you get in a controlled setting where she has access to only one male) or with the sperm of several male cats (think wild cats). So, while all those kittens are born at the same time, genetically they'd be as similar as we are to our (half-)siblings and not genetically identical as with identical twins.",
"Human twins aren't always identical twins. There's basically two different kinds of twins: Identical which happens when the fertilized egg splits into two, which then turns into two babies instead instead. Then there's Fraternal twins, which just means there were two lucky sperms instead of one, so there's two fertilized eggs to start with.\n\nCats reproductive systems result in multiple fertilized eggs as part of normal operations, so much so that kittens of the same litter can actually have different fathers!\n\nFun Fact: Generally speaking, you can tell how many offspring there \"should\" be at once by counting nipples, average litter size is half the number of nipples. Humans (generally...) have 2 nipples, and our average litter size is around 1. Cats have 8 nipples, and their average litter size is around 4."
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4i0kog | how are humans so good at throwing things? biologically. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4i0kog/eli5_how_are_humans_so_good_at_throwing_things/ | {
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"Evolutionarily? Humans evolved to throw rocks and spears, as the other commenter said. Physiologically? Humans have the right arm muscles and bone stuff to throw things. Animals that walk on four legs can't rotate their arm to lob something because their shoulder blades are in a different position. Humans also have binocular vision and the brainpower to know how hard to throw thing.",
"Also to add to other comments, the way the body and muscles are, humans are better st throwing things than other animals because we are able to contour our body and use joints as a fulcrum and giving us ability to shift momentum. Think of a baseball pitcher, they draw a lot of their power from their legs and hips; they are able to wind up their arm due to our shoulder muscle and joints, power gets shifted from my legs, through the hips and channeled through my arm all the way through the flick of the wrist. If you YouTube \"baseball pitcher slow-mo\" you can visually see how the body is moving to propel leverage throughout the body. "
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csskyf | why can we recreate sounds in our head, but it's impossible to recreate a smell? | Or maybe I'm just special and I can't do that, who knows?
Someone here hopefully! | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/csskyf/eli5_why_can_we_recreate_sounds_in_our_head_but/ | {
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"It's not impossible, its just about training and wiring.\n\nVision is the sense we use to navigate the world most of the time. Even when we use other senses, we still use vision alongside them. Because we're constantly looking at things, a huge part of our memory is dedicated to remembering images, and so we're able to conjure images mostly at will (although curiously, we don't have full control of the images we conjure). \n\nThe second most important sense is hearing. We use sound to communicate, and communication is something so vital to the human condition that we gave up part of our working memory and short term memory to do it. Sound is also the next best thing after vision (and the best thing at night) for figuring out what's going on around us. \n\nAfter that, I'm going to rank taste. Taste is a major component of how we determine foods that are good for us and foods that are bad for us, so we have a relatively refined sense of taste. However, we don't spend much of our time actually in the process of tasting things, so it doesn't get honed very much. People who eat quite frequently, like chefs, do develop a good palate though and can conjure tastes at will. I'm not a chef, but I do like meat, and I find that i can recreate the taste of a good steak to a similar level that I can recreate sounds and images. \n\nThen there's smell. Smell is also something we use often to determine toxic materials, including food, but unlike taste, we're always smelling things. So why can't we conjure smells at will? That's because the brain tunes them out. Smells, other than those that are straight up disgusting, are notable at first but then fade out. We stop paying attention to them, and before we know it we can't voluntarily pay attention to them again, even though they're still there. Unlike vision and sound which are always on, smell only cares about *changes* in odour, so even though we're always smelling things, our brain learns to memorise smells only when smell changes. Note that people who work with scents often, like perfumists, can learn to recreate smells in the same way a chef can recreate tastes. \n\nFinally, there's touch, which is a bit of a curious one. We don't bother remembering the sensations of picking objects up, because that's just not important to us - we only need to learn sensations that affect us, not ones that are the byproduct of us doing things. We actually don't get touched that often, at least on average, so its hard to learn what being touched feels like. I have no idea if its true, but I think its possible that people who often get massages or engage in competitive contact sports may develop the ability to recreate certain touch sensations.",
"Brains are weird. \n\nI can't do images or sounds. Apparently some people can do taste and smell. \n\nAphantasia is weird. Nobody knows why."
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63gudz | why is it that smiling, in human body language, is a sign of happiness and acceptance, while in chimpanzee body language, it is a sign of fear and anxiety? | With being so closely related, I'm confused on how we use such a prominent action so differently. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/63gudz/eli5_why_is_it_that_smiling_in_human_body/ | {
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"While we are closely related genetically, it's worth noting that humans and chimpanzees share a common ancestor between 4-13 million years ago. In that time, both branches of the taxon have developed wildly differing tool cultures. Human language and chimpanzee language are tools. There is no inherent genetic component.\n\nAs a matter of fact, humans aren't even of one mind on smiling. [This article](_URL_0_) from Rensselaer Politechnic has an interesting article on differing uses of the smile in non-verbal communication:\n\n > A smile may show affection, convey politeness, or disguise true feelings. For example many people in Russia consider smiling at strangers in public to be unusual and even suspicious behavior. Yet many Americans smile freely at strangers in public places (although this is less common in big cities). Some Russians believe that Americans smile in the wrong places; some Americans believe that Russians don't smile enough. In Southeast Asian cultures, a smile is frequently used to cover emotional pain or embarrassment. Vietnamese people may tell the sad story of how they had to leave their country but end the story with a smile.",
"If I'm not mistaken it actually isn't. It depends on the culture you grew up in. In some countries such as America, Australia, or Brazil it's a happy/good thing. I remember reading that this was not the case in countries such as Russia or Pakistan. Apparently in those countries it's a sign that someone is a con artist or dishonest if I remember correctly?\n\n[Not the article I was looking for, but an interesting read.](_URL_0_)\n\nI'll keep looking for the article I wanted on it.",
"It has some basis in body language development, I believe. For chimps or many animals, 'smiling' is baring the teeth, which is a defensive posture. It's a way of saying 'don't antagonize me'. It is like unsheathing a weapon, in part because they actually do use their teeth as weapons.\n\nHumans, by contrast, do not use our teeth as weapons because they are poorly designed to be used as weapons. Human body language over thousands of years has developed to be concentrated on our highly mobile facial muscles. While we do take some body language cues, most of our expressions are in our faces. While smiles mean different things depending on culture, they are not viewed as a threat because they are not typically used as weapons except in the most dire circumstances ",
"I'd like to point out that while chimpanzees grin to show fear and anxiety, it's not always in response to some negative stimulus. Excitement, both good and bad, can elicit a similar grin, such as when they see a particularly favorite treat. There may be some subtle differences between the types of grins, but a need for understanding the context of the grin is important when determining the \"emotion\" being displayed.",
"I'm actually curious as to why animals don't become defensive when we smile at or around them if it's usually their way of showing aggression",
"The baring of teeth in chimpanzees is a not-so-subtle gesture that says \"if you try and hurt me, it'll cost you\". It's not a threat of murder so much an appeal to a sense of self-preservation in the other. It's a common gesture, too. Nearly every species has a threat response, and a number of them involve the baring of teeth. \n\nWhat does that have to do with human smiles? At some point in our history, the baring of teeth, combined with an upward curl of the mouth's corners began to mean \"I'm not so bad, we could be friends\". We do, however, still retain the baring of teeth in expressions of anger, fear, disgust and joy. The baring of teeth seems to heighten the effect of the expression.\n\nThat might be the key to this question. If baring teeth in human expression is merely an enhancer of the underlying expression, then chimps may be baring their teeth as an enhanced version of an underlying appeasement gesture that has no exact analog in humans."
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1iogue | in a country filled with many different ethnicities, why are african americans the stand out race when it comes to racism? | Is it just me or is the racial conflict found in the US basically only between two races, White Americans and Black Americans? I don't remember the last time another race, other than African Americans, made the news regarding unfair treatment. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1iogue/eli5in_a_country_filled_with_many_different/ | {
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"I have two guesses, but I can't say anything for sure.\n\nMy first guess would be that since originally the vast majority of African Americans were slaves, that people considered them inferior. This could have carried over since then, diminishing in scope of how many, and how much, people thought this. At this point it shouldn't still be around but it is.\n\nMy other guess is that since the original Americans (note, I'm talking about the country, and not the land itself) were white, and the majority of Americans, especially in past years, were white, African Americans were simply the most different, in terms of looks. Other ethnicities can have different skin tones, but African Americans are the darkest, and therefore stand out the most from the majority of Americans.\n\nThose are the only reasons I can think of",
"People just don't like anyone that's different from them. \n\nMaybe because the Trayvon stuff you think that they're only racist against black people, but don't forget how much Hispanics are discriminated against, how Asian Americans were put in holding camps during WWII, and how currently, we view anyone who wears a turban as a terrorist.\n\nBlack people can be just as racist towards other races. The same thing goes for Native Americans, Hispanics, Asians, and everyone else. \n\nThe truth is, there's a handful of people who keep us fighting amongst ourselves. Why should I hate someone because they look different than me, have a different disability than I do, or because they choose to sleep with someone I wouldn't sleep with? \n\nIt's really petty that we're allowing ourselves to be swayed by other people's hates, when we should just mind our own damn business because we really are no better than anyone else we meet. ",
"There's a sociological theory that explains this.\n\nEssentially, people sort ethnic categories based on two criteria. Their status as superior or inferior, and their status as insiders or outsiders. White Anglo-Saxons are, in most of the Anglophone world, Superior Insiders. This means that they are assumed to be good until proven otherwise, and that they generally aren't seen as monolithic group or seen as \"exotic\".\n\nGenerally speaking, East and South Asian migrants are \"Superior Outsiders\" (this varies greatly depending on location. The Vietnamese are generally considered \"inferior\" in Australia, but this distinction often isn't made in other countries). They are acknowledged as *very different*, but as \"good\". This is why they are sometimes called the \"model minority\". Racism against East and South Asian migrants is usually far more subtle and centers around racially-based assumptions rather than racial hatred: it's more based on ignorance than deep-rooted racist attitudes.\n\nMiddle Eastern immigrants are Inferior Outsiders (again, location permitting). Outsiders because they form their own neighborhoods and practice their own customs, inferior because their migration is generally viewed as negative. There are often allegations of racism towards this group, but due to their status as \"outsiders\" these are rarely heard unless they are extreme or violent (i.e. bombing of a mosque or temple)\n\nIn the US, African Americans are Inferior Insiders. They are \"inferior\", and so experience racism, and their voices are often heard because they are a large, \"insider\" group: one that \"belongs\" in the US without any novelty value."
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ukiog | why banks are so eager to have you refinance to a lower interest rate | If I'm paying a bank 5% on my mortgage, what incentive do they have for me to refinance and pay them less? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/ukiog/eli5_why_banks_are_so_eager_to_have_you_refinance/ | {
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5xilv4 | how can so many artists now produce incredible photorealism, when even the greatest renaissance artists that saw that as a central aim couldn't come as close? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5xilv4/eli5_how_can_so_many_artists_now_produce/ | {
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"You mention simple materials, I would imagine years of development would change how the materials are made and have probably improved the quality of the materials to allow a much more realistic drawing.\n\nAnother factor might be how easy it is to access and share knowledge. You might be naturally a great artist, but it must be a lot easier now to learn new techniques in a short space of time than it was back then which likely used to take many years to master. ",
"The ability to work from a photograph (and to extrapolate the skills learned this way to drawing live models). A lot of renaissance work - particularly in portraits has the hallmarks of using a camera obscura (basically an image projected in a lightbox) which has a few issues in terms of scale (often the person's head is in focus but their shoulders aren't, also head looks giant compared to torso). Don't forget as well that painter in that time was much more of a craft than an art - painters needed to earn enough to eat and sometimes that meant fudging things to suit the vanity of the subject/comissioner which necessarily adds some distortion. ",
"I think it's mainly because the new ones already have a 2D model (from a picture) while back then, they had to use 3D models (real people). Also, cumulative knowledge on perspective and such.",
"It's significantly easier to copy a picture (2D to 2D) than to draw one from a real object (3D to 2D). Still difficult, but easiER. All photorealistic drawings I've seen copy a picture. Also, you're comparing paintings, in which matching the color is waaay more difficult, to black and white pencil drawings, in which your brain does the coloring. ",
"A person will never sit still for days for the artist to be able to paint him/her correctly. Photos have changed things. You can now look up the subject of your art for every detail for as long as you want.",
"Another point is that photorealistic art looks like a photo; we modern people assume a photo is what the thing really looks like. That is a learned response. Yes, photos can be a very accurate representation of a person, but only at an instant in time, and in a particular light, and seen through a lens with a particular focal length. It doesn't completely capture the experience of being in the presence of a living, breathing, moving person.",
"The artists creating photorealistic art in the 18-19th century actually had access to semi advanced camera like devices that allowed them to project right onto the canvas. \n\n[Heres a great documentary about this](_URL_0_)",
"I think your comparison with trompe l'oeil masterpieces is not comparing like for like really. You can't compare a pencil drawing to oil painting as the medium affects the end result and oil paint is quite a thick viscous material that does not really lend itself to fine details in the way that a pencil or ballpoint does.\n\nI also think the increase in realism over the centuries has two causes, one is that as technique improves the next \"great\" artist has to up their technique to be successful in the same way that Olympic records are broken for a more mundane example.\n\nThe second change is technology and scientific discovery, as human knowledge and technology changes human perception changes too. As printing improved and photography appeared peoples perception of realism changed to match the level of detail these new techniques brought with them. For us in the modern age it is for example quite normal to think of a picture being made up of small dots or pixels but if someone were to think in that way in the 17th century would of been quite unique.\n\nOn another level it is debatable if level of detail equates to quality, a high level of detail at worst is only a indication of a certain level of craftsmanship and not a automatic indication of artistic merit.",
"Every artform, skill and technology advances massively over time. If we sent Magnus Carlsen or Floyd Mayweather back in time there is nobody that could defeat them. And it applies to every sport and every dicipline of everything and anything.\n\nSome skills have been lost to time of course, but any skill that still lives has evolved to be better today than ever before.",
"I believe it was also a 'thing' for artists to follow a certain style of depiction that was popular at the time, be it traditional or modern. I remember learning in my art history class that a piece like Siena's Maesta was painted that way not because they couldn't achieve realism, but because it was traditionally 'correct' to depict the Madonna, Christ Child, and Saints that way.",
"I would like pose another version of your question. How did sculptors create such life like images from marble and other stone yet various paintings did not compete? I understand as other have said that the technology for fine point pens vs oil painting is different enough to not portray as good of details. I don't see exactly how that isn't the same for sculpting.",
"Because nobody had a clue what a true photographic images looked like until the invention of the camera. ",
"Very simple answer. In Renaissance, there were no photographs. Its rather easier to make a photorealistic painting if a) you have a photo b) you painting it with tablet and touchpen.\n\nAlso they didnt actually want photorealistic paintings cause a) they didnt know what that means b) portraits and other stuff was ordered usually to be nice, not true to reality.\n\nAnd as far as colors go, some of more recent artists were better than photos.. (early Monet stuff for example).\n\n**TL:DR Most photorealistic things are based on a actual photos. That wasnt a thing in Renaissance. It makes creating them far easier.**",
"I have seen still life paintings in the Rijksmuseum that are photorealistic. Wasn't that the whole point of the art form?",
"The renaissance painters were the pioneers of the technique. Over the ages we've improved on their groundwork. ",
"One of the things you aren't thinking about is how cameras tend to alter values, color and contrast. Artists who simply copy photographs, like the one you showed, are just following what a camera shows. Renaissance artists painted from real life. There is a big difference between how something looks in a photograph and how something looks in real life. Realism painting has been around for a long, long time.",
"I'd point out that many photorealistic paintings, like those by Chuck Close, are gigantic and are only photorealistic when viewed from a distance or in print whereas the Mona Lisa is on a pretty small 30\"x21\" canvas. \n\n_URL_0_",
"Nobody said it yet, but in addition to all the other explanations, there is also the fact that there are just more people doing it. And with more people doing an activity, there will always be more chances of something great happening compared to when only a few people did it.\n\nToday, the human population is something like 7 billion, and there are a lot of people who can practice arts and with tons of information (anybody is just a few clicks away from learning about all the best painting techniques).\n\nBack in renaissance time, human population was just 1 billion, and art wasn't accessible to a lot of people.",
"In short, because the great artists of today have learned from the great artists of the last generation and they learnt from the great artists of the previous generation and so on.\n\nI recently read a great book this discussed this, amongst other things. Civilisation is built on the work of previous discoveries. Someone today gets to learn everything that previous generations didn't know and they get to use technology that previous generations didn't have. They might spend their whole live working or training and discover a better way of doing things which in turn they can teach to younger people who'll take that and everything else and repeat the cycle. The book was Bounce by Matthew Syed.\n\nA great example of this is athletics. If you go back and look at the records for say the marathon over the years it's got quicker and quicker so much so that a world record time 100 years ago would be considered a good time for an average runner. We know humans haven't evolved over such a short time, nor is equipment so different, so what happened? Training got better. Over the years we learnt more and more about training methods and nutrition. The stuff elite athletes were doing filtered down and we all improved and then the elite athletes had to find a new way to get ahead.",
"I think [this](_URL_0_) by Albrecht Durer is pretty close to expert modern standards of realism, with the materials he had available.",
"You do the best you can with the tools and knowledge you have. The Renaissance artists were great because their works were leaps and bounds ahead of those who came before them. They didn't have computers, perfectly categorized pigments, or micro-millimeter paintbrushes to work with, but incredibly crude tools that required an unbelievably fine touch to work with. A good analogy would be a medical genius trying to do brain surgery with a butter knife.\n\nIt's not that modern artists are better or more talented, but they have better tools and more cumulative knowledge than those who came before them.\n\nIt's actually one of the coolest things about human development of *everything* over history: we're just going to get better and better at what we're doing.",
"...because photos weren't invented yet?",
"Modern artists can achieve photorealism because they are copying from photos.\n\nPhotographs are images captured by a device. The capabilities and settings on the device determine how the image will appear - change the settings slightly and you'll get a very different image. Therefore, a photograph is not explicit reality but a version of it captured in a certain moment, under certain conditions, at a certain angle, by a certain device with certain settings (selected by a human, which is why you should reconsider photos/video as a kind of objective reality in the first place - think about this when watching the news or Youtube).\n\nGo outside and take a photo. Now look at the scene with your eye and compare it to the photo. You should be able to notice differences.\n\nNow come back an hour later and look at the same scene with your eye. At minimum the light has changed, objects might have moved, cloud cover changed, etc.\n\nConsider that creating a detailed painting takes many hours. \n\nConsider that while the artist is working, the conditions of the scene will change.\n\nConsider that when working from a photo, nothing changes. Even the conditions under which the artist views the photo itself do not change since we have the luxury of electronic artificial light.\n\nWhen working from a photograph, the artist is copying a vision captured by a machine; when working from reality, the image produced is built directly from the impressions of a human without the mechanical middle-man.\n\nSo: which method represents reality more accurately as a *human perceives it*? Of course, the question itself only leads to more questions ;)\n\nMy background: I have a degree in fine arts and prefer to paint in oils. I use photographs as a reference for anatomy, proportion, colour but build the image according to whatever imagination inspired it.",
"So apart from ease access to knowledge, professors, books and youtube, as well as constant evolution of all these, to me it's being able to pratice and hone your skills. Material for painting was very expensive and limited sale...people mainly strugled to have food.\n\nIt's just like comparing photographs 15 years ago and today, just for your phone to have a camera makes it easier to study and pratice the art.",
"It probably helps that today's artists have seen photos, and are used to seeing exact two-dimensional images of people.",
"The answer is in your question. There were no photos in the Renaissance, so there was no photorealism to speak of.",
"imo none of these answers are actually addressing OP's concern. You don't always need a photograph in order to paint realism per se. You paint what you see. Why weren't most artists during the Renaissance doing this, or at least painting from memory?",
"Some artists of the renaissance used tools to simulate realism, like camera obscura. Photorealistic techniques of today are simply copying a photograph. If you have a static image to copy, it's easier to get everything right.",
"Photorealism didn't exist back then because photography (unless you believe the Leonardo faked the Shrod of Turin theory) didn't exist yet.",
"As an aside, you'd probably be interested in watching [Tim's Vermeer.](_URL_0_) Arguably, one of the first artists to produce \"photorealism\" well before the photograph had been invented. The full documentary attempts to recreate his method and it's super interesting.",
"**short answer:** At the time of the Renaissance in Italy, someone could feed themselves by painting pictures. So you better paint some awesome pictures. \n\nHowever making paintings is both a skill and a technology. Skills and technology can be forgotten and lost if enough people don't use them enough. \n\n**to continue on:**\n\nA thousand years before the Renaissance, there were people who could make and use those tools very very well. The Romans. However their civilization fell apart and that knowledge was lost - those skills no longer fed you. \n\nEventually a new civilization emerged and people began to use those tools again and use those skills again and refine the tools and refine their skills\n \nIt is a pretty cool because two of those guys who were using those skills and tools, Brunelleschi and Donatello, went to the ruins of Rome and rediscovered great works of art. They reverse engineered lost techniques, skills and tools to help make what we call the Renaissance. \n\nIt is interesting to see how in the history of art, you see it go from primitive/simplified to realistic to simplified to realistic. Given enough time of continual development, it even went abstract and beyond. \n\n**To address realism specifically**, Hellenist (Ancient Greek) sculpture is strikingly realistic. Even cooler... hundreds of years later, the Romans found it fashionable to portray the \"Realistic\" image of people - warts, scars and all. \n\nSo yeah, the Renaissance was a time when a stable and wealthy culture arose and there happened to be enough intelligent and curious people to use their knowledge of craft (Brunelleschi was a silversmith) and to be paid well enough (Lorenzo De Medici has been called the father of the Renaissance and all he did was pay for most of it) to pursue their craft to such a degree that it developed into the art we know of today. \n\nAll of that development boils down to the fact that were enough resources to allow for this technological development. ",
"This will probably be burried, but here it is.\nI have a studio art degree from a public university with an emphasis in oils. I was in school just a few years ago.\nWhen we began our photorealism classes, the professors taught us the technique of copying pictures, detail for detail.\nPainting from life and painting from image, are very different. \nNow, I hope this captures the spirit of ELI5, because I havent studied the human eye or how image transfer works in the human brain.\n We see in three dimensions, right? So when we look at a real life model we see every detail of the light against that three dimensional form. But to capture all of that in a TWO dimensional form is rather difficult. So I was taught to \"cheat\" at first. By painting from a photo, technology that didnt exist during the Renaissance, my eye is now translating a two dimensional figure into another two dimensional figure. Why this is easier for the human eye, I don't know. But from experience, it's definitely much easier to paint a convincingly photorealistic image from a picture over doing it from a real life person. \n\nAnd in response to the comment about the paintings not necessarily looking photorealistic, and instead just looking like \"Renaissance\"...you're half right.\n\nThe masters of the Renaissance respected the human form and got as close to life-like as possible. Photorealism (a term coined much later, at the turn of the century) was the holy grail. It meant more money, the more life-like the commissions became. In their minds, there was nothing better than the natural human form, nothing more beautiful, save perhaps their paintings of it. But they also glorified the human form much like the Greeks did before them. So the human figure was made to look much more lavish, much more exquisite, than it really was. (Some masters admittedly added more musculature to their sculptures and paintings than was anatomically correct.) And there were many iterations of this concept, a noteable contributer being Sir Reubens (the one that painted his ladies nice, rosy, robust, and chubby.)\nSo yeah, it was supposed to look even more beautiful than the natural form, but photorealism was absolutely a goal.",
"My knowledge is limited, and mostly about oil painting. I'd also encourage you to rethink the term \"quality\" -- oil paintings from 500 years ago have significant quality, independent of their anatomical accuracy. What we're really talking about is a change in style.\n\nI think a lot of people have answered this, basically it's easier to work from a photograph (steady, unchanging light source, unmoving object etc.) than it is a live object. Not to imply that photo/hyperrealist artists only work from photographs. Alyssa Monks (one of the best hyperrealist painters around) uses photographs, but rather than just copying the photograph she attempts to make the work move beyond looking like a photo... if that makes sense. \n\nWhat a lot of the top comments haven't mentioned is the massive developments of materials that's occurred since way back when.\n\nOil paints were, and still are in general, quite expensive. Rather than use one colour straight on a canvas, artists would often (read: almost always) do a monotone underpainting (grisaille), and use transparent layers of different colours to build values in the painting (like rather than mixing a red and blue to get purple, you'd do a glaze of red, wait for it to dry, then a glaze of blue). Different pigments layered in different ways produce different results in the overall image. These techniques are still used today, but generally not as a monetary necessity.\n\nWorking like this meant months spent on a single painting. That means that a model was sitting for an artwork for a significant amount of time, over different seasons, different times of day etc. And, obvs, they probably weren't sitting there the entire time. Which means the artist was working from memory, as well as their knowledge of anatomy, light, colour, and how they interact to produce a certain effect.\n\nIn the case of producing realistic skin tones, you might also take into account the paint/varnish ageing. Some pigments aren't as lightfast as others, and become faded; others yellow with time. Varnish often becomes yellowed with age. Of course paintings are often restored and maintained nowadays, which helps combat this.\n\n**TL;DR:**\n\n* Digital technology: unchanging reference available whenever needed, don't have to rely on memory/imagination as much\n\n* electiricty: ability to paint in the same light (influences colour choices made by artist)\n\n* pigments are less expensive: techniques aren't as limited by money\n\n* more pigments available: more colours, cheaper colours\n\n* effects of age on painting: older paintings lose some of their lustre, so we don't see what they initially looked like, only the restored versions.",
"Eyeglasses.\n\nWhile eyeglasses are known to exist as early as the 1200's they were very expensive. The invention of the printing press in 1452 and the growing availability of books encouraged the production of inexpensive eyeglasses, but they were still costly.\n\nNot everyone who became a painter had perfect vision, nor did their patrons. Heck, just ask around the people you know, see who's got contacts. There were many people who couldn't recognize someone standing half an acre away. This set the bar for realism very low.",
"One thing I didn't see mention is the pure size of the population, and density of cities.\n\nA medium sized city today could compete against the biggest cities pre industrial revolution. Our biggest cities today could compete against whole countries. The best composer in the world at any given time back then was the best of millions, not billions. It was only the best of multiple generations that we even really remember, and those people we remember are often innovators at a turning point. ",
"You're making one huge, and rather wrong, assumption that photorealism was the aim of such works. \n\nArtists usually follow certain styles, and making something look life life wasn't necessarily the goal. ",
"Because they didn't have cameras to know what a photo looked like. Photos don't look like reality, they look like photos. People like Raphael were pretty on point when it came to like real people. ",
"I think the answer is photography! I´m an illustrator and I have some friends who make photoreal illustration and they use photographs as reference all the time, also, nowadays you have 3d software too, so you can for instance pose a car in perspective and paint on top of it, adding your own details and variations while knowing the perspective is correct and not have to think about it. \n\nPhotoreal illustration is heavily demanded in some areas such as advertising or videogames, so with demand people start figuring out ways of doing it.\n\nI also have to say your example is not the best, see Vermeer for instance, who allegedly used lenses and optical tricks as the \"camera obscura\" to compensate for the lack of actual photographic technology and achieve his own degree of photorealism: _URL_0_",
"I'd never understood the point of striving for photorealistic images as non-photographic forms of art. Why put in so much time, work, and effort to attempt to match a form of art that can do it all so well already?",
"Artists of past generations used to look down on photorealistic artwork. They valued style and the artist adding a their own voice to the artwork. They believed realism was lazy, anyone could copy real life but an artist gave you more than what was there. \n\nIf you look at the artwork of John Singer Sargent, he started in America doing paintings that utilized realism but since the American art scene was scarce he went to study art in France. His style changed work European influence and he shied away from realism and incorporated some impressionist tones. \n\nSource: BFA Degree",
"The method used by Photorealist are technological. They use something called a value mapping to pinpoint exactly where the contours, values and shift of tone occur. This can easily be done with a projector and a pencil with a high clay content a la 7h to trace, and a rigid smooth primed surface a la a board with a gessoed and sanded surface to trace on. The methods of mixing paint today are much easier with formulas available online on how to generate specific chroma. Photorealistic Grisaille, monochomatic studies, are something that complete painting amateurs can do it if they follow a specific protocol. \n\nPhotorealist is a nothing more than a supped up version of paint by numbers.\n\n\n\n",
"Renaissance artists didn't have photographs to work from. The best representation of an image was the image they could themselves create. ",
"When I was 20 I took my first college drawing class. I was amazed at how awesome I was because our early assignments were to take photos and copy them, and I worked hard and did pretty damned well! I was probably in the top couple of my class. Hot shit. Fast forward to the \"real\" drawing classes. 10 minute figure drawing poses in charcoal. Good god did I suck. It took years of life drawing, sometimes 3 hours/day x 5 days a week, and several different teachers and dozens of books, before I would be able to produce anything worth looking at, and anyone with an untrained eye would still prefer the photographic copies of my early days. The reality is that copying from photographs is a much simpler process than observing from reality. The fundamentals of drawing/painting (gesture, form, light, etc etc) simply aren't required to copy from a photograph, although the two aren't mutually exclusive. ",
"Renaissance paintings follow a certain style, they weren't trying to achieve photorealism they were trying to achieve Renaissance. ",
"I think the simplest explanation would be the fact that artists today can base their works on photos instead of live subjects under ever changing natural light. Copying a photo is much easier than depicting a live subject.",
"How could the Renaissance aim for photorealism when photography didn't exist?",
"One thing that a lot of people are missing is a lot of the technology has improved.\n\nWe can make better pigments in more colors than ever before. We are better at making what holds the pigments together. We can choose the viscosity we want from our paints with incredible ease.\n\nWe are better at putting those pigments in containers. A renaissance painter for example had to use an animal bladder to hold the paints that they hand made themselves. If they wanted to put paint on a pallet they had to cut a hole in the bladder and squeeze out the paint. Than they had to seal the hole using glue and a patch. They had to do this to keep their paint fresh and the color strong. Today we have aluminum tubes that we can simply squeeze paint out of. This saves the artist time and gives them the ability to quickly choose between the tons of new pigments we have created.\n\nWe have a better tools for applying paint. Not only have synthetic brushes improved to an amazing point, the average person in a developed nation can easily buy natural fiber brushes from all sorts of animals from all over the world. Additionally we have tools like airbrushes. Our pencils and pens are far better.\n\nWe have better understanding of color. So while it is true that scientist Sir Isaac Newton discovered how light and color are related, it wasn't until much later that we had a deep and sophisticated understanding of how the mind and eye understand color in relationship to each other. This understanding actually came from weaving textiles, and learning how colors next to each other can make each other appear more vibrant or duller.\n\nAll this together plus the invention of photography as other respondents have mentioned, simply let modern artists do things that renaissance artists couldn't even approach.\n\nInterestingly, if it wasn't for that weaving thing I mentioned, coal refinement, and aluminum paint tubes there would never have been impressionism.",
"Pre-photograph = transcription of form and light. \n\nPhotorealism= Methodically copying \n\nPre photography- ideas about ideal form vs gross raw reality\n\nPhotorealism- conceptual-pop art about photography and its impact on how we see the world and view reality.",
"Photographs give us all an agreement on what a 2D representation of 3D space should look like that people never used to have. Our vision is not as straightforward as you would think. Optical illusions, for example, can show us some of the ways our vision is funky.\n\nIt is sort of like how we got used to seeing car tires spinning 'backward' in a movie as 24fps, or the sound of coconuts clapping together for horse hooves. Both of those things are unnatural, but feel right anyway because we've grown used to them.\n\nThere is actually a painter, Vermeer, who likely used a sort of camera obscura 350 years ago. They initially figured this out only because the perspective in the painting was accurate for photography, but wrong for human perspective. Photographic perspective, apparently, would have actually looked very strange to people back then.",
"photographs didn't exist in the renaissance.\n\nThe most realistic paintings possibly used lenses or camera obscura.\n\nPracticing off of photographs is one part of it.\n\nThe materials were not the same quality as today, the tools available not the same. Mixing every pigment and chemical from scratch...\n\nMy aunt could draw photorealistically from a very young age, so something in the brain has also developed over the centuries.\n\nI mean she was 4 or 5 drawing more realistically than \"masters\" of back when.",
"Your answer comes in a few forms.\n\nFirst, copying a photograph is not very difficult to do. It's essentially a half step up from tracing something directly. Most photorealist painters will use a mechanical process, like a grid and measurements, to recreate the photo. You could do this yourself with a little training and practice. Painting from real life, on the other hand, is the most difficult kind of painting you can do. Renaissance painters didn't have any photos to look at.\n\nSecond, Photorealism is just that - reality as seen in a photo. Real life is not photorealistic. Cameras make all kind of lense distortions, blurs, color modifications, etc, that we've come to accept as more realistic because almost all of the pictures we see are photographs. Renaissannce painters were certainly interested in making something dimensional and realistic, but their paintings don't have camera distortions, so you may read it as less realistic when it really isn't.\n\nThird, Renaissance artists, along with most other artists up until the 1850's or so, were interested in idealizing people and landscapes to be as beautiful as possible. They weren't interested in painting pores and wrinkles, nose hairs, sweat, and the other things that make something look completely lifelike.\n\nAll that said, there are a few artists throughout that period who aimed to make their paintings look as real to life as possible - Like Rembrandt: [Link](_URL_0_) and [Link](_URL_1_). It's not photorealism because it doesn't have photographic artifacts, but it's realistic to the point where, standing in front of it, it looks like a real person.\n\nAlso remember that, when you're looking at a painting on a computer screen, you're not looking at the actual painting. It's very difficult to get a good picture of a painting because they have 3-dimensional surfaces and glazing effects that work with the light shining through them.",
"I would assume that the two main contributors are:\n\n1. Being able to have a photo as a reference that is consistent and you can make nots on etc. compared to a live model that moves and changes and would only sit for a few hours. \n\n2. Now artists largely start out with passion and do it as a hobby. They have time to practice and refine their skills and them the money come as a bonus. Back in the renaissance they were doing it as the only source of income so near enough is good enough if you are due to get the money you can move onto the next client. ",
"lower quality tools/pencils/paint ect?"
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"http://images.metmuseum.org/CRDImages/ep/original/DP145921.jpg"
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||
7af9dw | how did old guitar effect pedals actually produce effects such as reverb & delay? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/7af9dw/eli5_how_did_old_guitar_effect_pedals_actually/ | {
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"I'm not too sure about delay, though there were some 'tape delay' units that worked like cassette tapes, except the tape was in a small loop. It had both a record head and read head running on one tape, so it would record the input from the guitar and play it back after a short delay. You could adjust the delay by adjusting the tape speed. In theory you could adjust the delay by changing the distance between the heads also, but I'm not sure if this was done as it would be more complicated. \n\nFor reverb the old school way (might have been others) was called spring reverb. They stretch a string between two moving coils, which work similar to how a speaker and microphone work (electrodynamic speaker and mic, anyway). One end of the spring is vibrated by applying the input signal to the coil, making it move like a speaker. The waves would run down the spring and go back and forth, and interact, kind of like how sound waves would bounce around a room and interact, and reverberate! At the other end of the spring, that coil would be used as a microphone to pick up the sound and add it back to the signal that's being fed to the amplifier.\n\n"
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5lf6ni | how to type korean? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5lf6ni/eli5_how_to_type_korean/ | {
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"Korean isn't a logographic language like Chinese. It has an alphabet, just like English, made up of consonants and vowels. The major difference between Korean and English (and other alphabetic languages) is that in Korean, you group the letters of each syllable and write them on top of each other. 사랑해 (\"saranghae\") is just made up of three syllables - 사, 랑, 해 - and each of these is made up of two or three letters: \n\n* 사 = ㅅ + ㅏ\n* 랑 = ㄹ + ㅏ + ㅇ\n* 해 = ㅎ + ㅐ",
"Korean uses an alphabet called hangul. Individual letters are composed into syllables, with each syllable occupying one block. This means that the computer needs to know when you have finished typing one syllable and want to start typing the next: fortunately, the Korean writing system has very strict and simple rules that are quite easy to program into a computer.\n\nA syllable must start with a consonant, and must contain at least one vowel; it can then have another consonant at the end. The consonant letter \"ㅇ\" is \"ng\" at the end of a syllable, but silent at the beginning of a syllable, so this lets you write syllables beginning with a vowel *sound* without breaking the rule that in written Korean, all syllables must begin with a consonant.\n\nIn your example, \"saranghae\" is \"사랑해\", the three blocks representing the syllables \"sa-rang-hae\".\n\nFirst, you type an \"s\", which in Korean is \"ㅅ\". Next comes a vowel, \"ㅏ\"; when you type that, the \"ㅅ\" changes to \"사\", the syllable \"sa\".\n\nThat's fine, but then you type the Korean \"r\", which is \"ㄹ\", but the computer initially thinks that you are typing the syllable \"sar\" or \"sal\", and so it gives you \"살\". At this point you panic, because that's not what you want.\n\nBut don't worry, because the moment you type the next letter -- another \"ㅏ\" -- the software knows that you can't start a Korean syllable with a vowel letter. And so now it knows that the \"ㄹ\" needs to go in the second syllable, changes the \"살\" back to \"사\" and starts a new syllable \"라\".\n\nNow you type \"ㅇ\", and the \"라\" changes to \"랑\", the syllable \"rang\".\n\nNext, type \"ㅎ\". This is a consonant, so the computer knows that it can leave \"랑\" exactly as it is and start a new syllable. Finally, you type \"ㅐ\", the \"ㅎ\" changes to \"해\" and you're done.\n\nSo in fact, if everything is working properly, you should just be able to type the Korean letters \"ㅅ\", \"ㅏ\", \"ㄹ\", \"ㅏ\", \"ㅇ\", \"ㅎ\" and \"ㅐ\", and the software will automatically convert it to \"사랑해\" without you having to do anything else. You do have to make sure you have a Korean keyboard and you have switched it to accept Korean (a Korean keyboard can be toggled between Korean and English input; for example, if you want to type a web address, you normally have to use English input mode)."
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1zbjo4 | common law marriages | I'm not really understanding. What exactly is stopping someone that is having their possessions threatened in a common law relationship trail from just claiming that their ex. S.O was nothing more than a roommate? No arguments against this simple claim is coming to mind. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1zbjo4/eli5common_law_marriages/ | {
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"If you claimed tax privileges for common law marriage during the relationship, that's a bit of a give away.",
"The court is going to look at the evidence, not just someone's claim. If you held yourself out to the public as married, claimed tax exemptions as a married couple, combined finances as a married couple, etc. "
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815pu7 | how does mouth numbing gel work? | [deleted] | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/815pu7/eli5_how_does_mouth_numbing_gel_work/ | {
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"text": [
"In order to conduct signals, including pain and other sensations, nerve cells need charged ions to be able to move in and out of them using special channels, which creates the electrical currents that transmit the signals.\n\nBenzocaine, which is the main ingredient in Orajel, blocks one type of these channels, keeping the nerve cells from working properly and thus blocking sensation."
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76gw2r | how do animals know the concept of winning and losing? | I was watching Planet Earth II and watched Komodo Dragons fight in order to mate with the female Komodo Dragon. They fought and stopped as soon as one topples the other. How do they know the concept of defeat and not continue on with the fight until death? How did these mating rules even develop?
Thanks! | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/76gw2r/eli5_how_do_animals_know_the_concept_of_winning/ | {
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"They don't \"know\" in a conscious sense, it just follows its instincts.\n\nThe whole point of these competitions is to see who gets to pass the genes down to the next generation. In general, the strongest animal wins, but there is more to it than that. If an animal tries too hard, it might lose and die, and clearly not pass its genes on. Even if it wins, it might suffer serious injury, and be unable to win the next time. Whereas an animal that backs off before it gets hurt will survive to try again another day.\n\nThe animal that is both strong and best able to balance trying too hard and not trying hard enough it the one who is the most likely to pass is genes on. After several generations, this behavior gets more and more refined until it is more of a ritual competition than a battle."
]
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3zktaj | why are mods on default subreddits deleting all news about the sexual assaults carried out by hundreds of north africans in germany? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/3zktaj/eli5_why_are_mods_on_default_subreddits_deleting/ | {
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"This is hardly a 'complex concept' that you'd like explained, although one obvious reason might be that you're spamming the same comment & link to dozens of threads and subreddits, labelling it more serious than various things such as terrorism, so maybe you shouldn't be surprised when your activism triggers anti-spam behaviour."
]
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1r6z4w | - no child left behind...how could anyone have ever thought this idea would work? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1r6z4w/eli5_no_child_left_behindhow_could_anyone_have/ | {
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"Probably because the people who thought it would work were left behind as kids.",
"It's like everything else with education, it sounds great when the only experience one has is sitting in school as a student 40 years ago. Then the corporate interests go into monetization mode and profit/political motives give a flawed policy tons of momentum.",
"Companies that provide the test grading hardware and companies that produce the textbooks stood to gain a large amount of profit. There's your ELI5 answer. But to generalize further--- all goverment programs that include private contracts function this way-- the data they use to reach conclusions that may benefit the society on social programs are predated by private institutions interested in only one thing- increasing their private wealth. \n\nNo child left behind has been a devastating consequence of the privatization of public education. \n\n"
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18ujob | formula one racing. | Totally new to all things racing.
How do you win a "season"?
Why do "teams" have two racers intstead of one or 10?
How does someone in the US watch races?
Are there any great historical races I should watch?
Just the basics so I can start watching some races and know what all the drama's about! | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/18ujob/eli5_formula_one_racing/ | {
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"1st : 25 points\n\n2nd : 18 points\n\n3rd : 15 points\n\n4th : 12 points\n\n5th : 10 points\n\n6th : 8 points\n\n7th : 6 points\n\n8th : 4 points\n\n9th : 2 points\n\n10th : 1 point\n\nWhichever driver gets the most points in a season wins. Ditto teams or \"constructors\".\n\nEvery team has to field two cars in every event each weekend and can use a Max of four drivers per season IIRC. \n\nThe rules are changed every few years with more emphasis on safety, normally. In the 1960s you almost expected to die. There are also lots of rules and regulations on maximum spending and technical stuff.\n\nWatch \"Senna\" about one of the greatest drivers ever, Ayrton Senna. The day he died he held a meeting about driver safety after a driver died in a practice or qualifying session, Senna later died after hitting a wall at 130mph.",
" > How do you win a \"season\"? \n\nBy scoring the most points from races (one for the most successful driver and one for the most successful driver). Currently the points are awarded like this: 25 for 1st place, 18 for 2nd, 15 for 3rd, 12 for 4th, 10 for 5th, 8 for 6th, 6 for 7th, 4 for 8th, 2 for 9th and finally 1 for 10th.\n\n > Why do \"teams\" have two racers intstead of one or 10?\n\nTo create a more diverse racing field while the better teams can still show off that they know what they're doing.\n\nThe drama? It's a combaintion of what makes their cars the best. Some drivers are better maintaining the tires so they can run longer stints. Other ones are better at making takeovers. Some cars are just simply better made to help drivers do these thing.\n\nThere's also a lot of strategy going on when you should do a pitstop to change tires (should the driver stay out a bit longer and do a few slower laps or should they come in early and have the advantage of fresh tires?). \n\nEdit: the stratgey bit can bit too much hands on from the team. Favourit segement from the 2012 season when Kimi Räikkönen tells his race engineer that [he knows what he's doing](_URL_0_)."
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2b6je2 | the tickling sensation in lower nuts region when high above ground? | I get a very weird sensation at the bottom of my nutsack when I'm high above ground or look up at something high. I am pretty scared of heights. Why in my nutsack and why he tickling feeling?
| explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2b6je2/eli5the_tickling_sensation_in_lower_nuts_region/ | {
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"text": [
"When you are scared, your body reacts. One reaction that evolution has left us part of our flee or fight response is raising your hairs to appear bigger. You can feel your skin contracting and raising your hairs the most in the most sensitive regions, for example, your scrotum."
]
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63h3cq | how does silica gel keep things fresh? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/63h3cq/eli5_how_does_silica_gel_keep_things_fresh/ | {
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"It absorbs the water / moisure / humidity. Preventing any damage from water to the boxes / items\n\nSilica get is not deadly. It's like pourous glass, it's non-toxic.\n\nHowever it can irritate your digestive or respiratory system.",
"Silica gel is a desiccant, meaning it absorbs water and keeps the relative humility low in a sealed environment.\n\nSilica gel is used where you don't want moisture building inside a container. Usually this is to keep fungus and bacteria from growing (if the environment is dry they can't grow). This would be the case for your shoes and certain \"dry\" foods (most commonly beef jerky and other 'jerked' meats).\n\nSilica gel is also commonly used in the packaging of electronics. For micro-electronics with exposed leads you don't want any moisture build up that could lead to a short.",
"If it's just silica gel, then it's a desiccant, meaning that it absorbs and holds on to moisture. That's not the only form though, and this is a good explanation of what exactly these things are and how they work: _URL_0_"
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5al8jf | why do some stores (e.g. gamestop) have multiple stores located in close proximity to each other? | I've also noticed that McDonalds and Starbucks follow this trend, in that there could be three or more Starbucks locations within a mile of each other. In my town, there are two McDonalds located across the street from each other. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5al8jf/eli5_why_do_some_stores_eg_gamestop_have_multiple/ | {
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"in some cases it's just such a busy area that 1 store would be too busy to handle all the business, and thus lose business because some people would not be willing to wait and go elsewhere. this is especially the case with starbucks and probably mcdonalds as well. in the case of gamestop, it's probably a mix of that, as well as the fact that they bought up a bunch of their competitors and made them in to gamestops. anything that used to be a software etc, babbages, or eb games either closed it's doors or became a gamestop (I think some of their stores still operate as eb games though so maybe not ALL of them did this). ",
"The design of a store like Starbucks looks to maximize efficiency. You want to use the space to the greatest effect. In general you don't want to end up with some sort of mega-monstrosity where you have 20 baristas working a 50 foot long counter. Same thing applies to McDonald's; I don't think I've ever seen one where it was more than 3-4 registers.\n\nNow, if business is *really popular* in the area, you might find this efficient store being overloaded by customers. Since, as above, we don't want to just tack on more counter space to our existing design, what we can do instead is build another location pretty close. If you choose the location well you would divert a good portion of the customers from Store A to new Store B.",
"Sometimes something as simple as adding a store to the south bound side of a street even with one on the northbound will create additional business. People feel its less out of the way and will be more inclined to shop there.",
"Sometimes a store is kept just to keep a competitor out of a prime location. If there is a busy mall, busy shopping center, and busy downtown all in close proximity, it's better to operate three stores (even if two really could capture most of the market) when the third store keeps a start up from capturing a prime location. ",
"Franchises operate in a way that can cause this. Say you operate a successful Subway restaurant. You are the franchisee in your town. Business gets really good. Subway corporation decides your town needs two outlets. They split your town in half. You are given right of first refusal on the new location. \nTwo things can happen. You agree to build another location. Your know your town and think another location up at the college would be great. \nOr you refuse and a new franchisee agrees to build a new location, they now lord over that half of town. But they aren't from your town and really need a success at this store so they look at the map and realize Subway corporation drew the dividing line awfully close to the original store. So they locate across the street from you because they know you are busy (why else is corporate adding locations right?) and half of a busy location is better than going into a neighbourhood where no one would want a sub. Or the original owners don't want to give a refusal to allow competition so they agree to take up the new location to protect their monopoly but they realize everyone in that town that is hungry comes downtown to eat so to fulfill their obligations they build the new store down the block. "
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3kx9go | how do scientists determine what "reduces the risk of cancer"? | It always says that a new study shows that doing/not doing something will reduce the risk of x cancer by y%. What are they studying? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/3kx9go/eli5_how_do_scientists_determine_what_reduces_the/ | {
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"They use a group of people and ask them questions. \"How much wine do you drink?\" for example. After some time they get back to those people and ask more questions or check their medical records - how many of those people got cancer? What habits were dominant in the cancer patients? With those questions the scientists try to find correlations.",
"It's called a [longitudinal study](_URL_0_). What you do is take a group of people (usually in the low thousands) and study them for a long time - 10, 20, 30 years. First, you divide them into two groups - in the first group, you do nothing. This is the control group. In the second group, you have them do something - exercise more, or drink a big class of grape juice in the morning, etc. \n\nAt the end of the study, you compare the percentage of people who got cancer in the first group with the percentage in the second group, and see whether it went up or down. \n\n"
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21n78g | why do many pictures taken from astronauts show a black background. | there is no atmosphere so shouldn't distant stars be easy to see.if i can see Orion's belt in a large city should astronauts see nothing but stars and galaxies everywhere | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/21n78g/eli5_why_do_many_pictures_taken_from_astronauts/ | {
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"text": [
"You can only have so much contrast in an image. Stars are faint compared to the light illuminating the subjects.\n\nThis is one of the reasons people think we didn't land on the moon."
]
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] |
|
29zsir | how exactly is the distinction between a 'developed' nation and a 'developing' one made? | Basically what constitutes a 'developing' nation, and what needs to happen for it to be considered 'developed'? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/29zsir/eli5_how_exactly_is_the_distinction_between_a/ | {
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"text": [
"There is no universal standard, but the [Human Development Index](_URL_0_) is probably as close as it gets. Even so, there is rarely a single line in the sand that constitutes \"developed.\" Many international organizations, such as the IMF, keep their own lists of which states are considered \"developing\".",
"English is not my first language, so please excuse if it sounds awkward. \n\nThere are many distinctions between the two, but a major one involves population size. Developed countries have either stable or falling population numbers. For example, Japan (a developed nation) is experiencing a falling population because women are deciding to have less children (ie 1 or 2), as well as having children later on in life. Women becoming more involved in the work force takes away time to raise children while they work to support themselves. In the US, the population remains stable because of immigration. Without immigration, the US would be experiencing a similar drop in population, but large numbers of people immigrating in to find better lives keeps the population stable. In developing nations, the population is usually rising. Many poorer families have more children than what would just replace their parents (ie 3 or more). For example, in India, before modern medicine, families had many children. Many young infants would die, so parents would have a lot of kids to ensure that they had some offspring to help with family business, usually involving farm work. Because this has happened for so many years, having large families has become cultural. Now that modern medicine has come into the country, the IMR (infant mortality rate) has decreased, but the number of children families have has not, so the population rises at a rapid rate. \n\nBy this logic, one way a developing nation could become considered developed would be by keeping an eye on the population numbers. But, as stated before, there are many other factors. \n\nHope this helps a little!",
"Developed nations tend to have:\n\n* fully industrialized economies\n* stable gov't with smooth transitions of power\n* effective rule of law within its borders\n* a well developed middle class"
]
} | [] | [] | [
[
"http://en.wikipedia.org/wiki/Human_Development_Index"
],
[],
[]
] |
|
75rck2 | if venus flytraps have chloroplast, why do they have the need to trap insects for food? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/75rck2/eli5_if_venus_flytraps_have_chloroplast_why_do/ | {
"a_id": [
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"text": [
"Plants need more than sun and water. Nitrogen, Potassium, and phosphorus being the most important. Flytraps and other carnivorous plants have evolved to grow in low nitrogen soil acquiring their nitrogen from the insects they \"eat\" instead. "
]
} | [] | [] | [
[]
] |
||
bi51nr | how does a baby supply oxygen in the first seconds mid/post childbirth? can babies obtain oxygen from the placenta and the lungs simultaneously ? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/bi51nr/eli5_how_does_a_baby_supply_oxygen_in_the_first/ | {
"a_id": [
"ely50iw"
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12
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"text": [
"In order for oxygen to pass from the mother's blood across the placenta, the baby's blood has a much much higher binding affinity for oxygen. Because of the higher affinity the amount of oxygen in the babies blood is way higher than adults. This extra oxygen can supply the babies body with sufficient oxygen for 5 or more minutes of not breathing with no problems. Once the first breaths are taken a chain reaction is initiated in the blood that drops the affinity for oxygen in the blood to normal amounts. After that the oxygen the lungs supplies the blood is used and relied on. Hope this helps."
]
} | [] | [] | [
[]
] |
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