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in football whats the point of wasting the first two plays with a rush - up the middle - not regular rush plays i get those | [
"Keep the defense honest, get a feel for the pass rush, open up the passing game. An offense that's too one dimensional will fail. And those rushes up the middle can be busted wide open sometimes for big yardage.",
"If you throw the ball all the time, then the defense will adapt to always cover for a pass. By doing a simple running play every now and then, you force the defense to stay close and guard against the run. Sometimes, the offense can catch the defense off guard by faking a run and freeing up their receivers.\n\nAlso, you don't have to gain massive yards on every single play. Sometimes, it works best to gain a few yards at a time. As long as you get the first down, you are in good shape.",
"In most cases the O-Line is supposed to make a hole for the running back to go through. If you run too many plays to the outside/throws the defense will catch on.\n\nAlso, 2 5 yard plays gets you a new set of downs.",
"I you don't like those type of plays, watch CFL. We only get 3 downs so you can't afford to waste one. Lots more passing."
] |
Why are different tiers (regular < mid < premium) of gas' prices almost always 10 cents different? | [
"As someone who uses quality Premium, I wish this was true.",
"The difference is in how it burns though is what's critical for you as the end consumer. I drive a forced induction car, so air coming into my engine is compressed before it enters the cylinder where it's further compressed by the piston. The Regular, Mid, and Premium gas are rated by octane, which in the shortest definition is how well it resists ignition, meaning higher octane fuel won't ignite from high pressure or heat, until the spark plug fires. Now that being said, you can look at as a price gouge, as it's not too hard to make higher octane gas, but cars that need it are typically sports cars as their engines run hotter, higher compression, and forced induction. Tying it back into what I said in the beginning, since I drive a forced induction sports car I have to run premium, and gas stations/companies know people like me are going to shut up and pay the extra 30 cents a gallon to protect our engines from lower octane gas detonating in the engine.",
"> Is this just an arbitrary convention that undermines arguments of a rational basis for gasoline prices? \n\nYou already know the answer."
] |
Stars and Visibility | [
"It's a quirk of the human eye. At the center of the eye (the fovea) we mostly have colour-sensitive cone cells to see detail and colour of what we're focusing on. Around the fovea we mostly have rod cells that can't see colour but are more sensitive to variations in light intensity and movement. \nLooking slightly to the side of the thing you're examining sends more of the light to the rod cells and lets you see things more clearly in low-light conditions where cones don't work well."
] |
How do we know all the money the government is getting from bank settlements is going back to the people? | [
"I'm pretty confident most of it isn't going back to the people. That's how politics works.",
"It's not. Punitive damages are like parking tickets. It is a fine you pay to the government.",
"> but I don't hear anything about where this money goes\n\nThe details of the various settlements differ. Some of it goes to a specific prosecutors office or justice department as part of ongoing operating revenue and costs, some of it lands back in Treasury, some of it can end up in victim compensation funds, some of it is costs incurred by the bank to do something that complies with the new rules (e.g. setting up new loans with new terms or something). \n\nWhenever it ends up back in treasury there's nothing to say, it's an irrelevantly small amount of money to the federal government. \n\nThe Bernie Madoff related stuff is going to include payments to people who lost money from that, probably through some complex legal proceeding there. \n\n_URL_0_\n\nHas a (very rough) breakdown of the 13 billion dollar settlement for example.",
"In almost all the class action lawsuits a large majority of the settlement goes towards legal fees/costs etc...It would be interesting to request a freedom of information act and ask to see the canceled check from JP MOrgan to \"United States Treasury\" for the 13Bil.",
"It doesn't matter that it's \"not technically\" going back to the people. It increases the government's spending budget so the taxes they would need to collect would theoretically be less.\n\nTheoretically..",
"you might ask the same question about income tax."
] |
What are good and bad sides of manual and automatic drive gear? | [
"Automatics weigh more, so that alone makes gas mileage worse. They are also more complicated, so that means reliability is going to be lower. It is easier to operate, which may free up your attention for focus on what is *outside* the car.\n\nSome people derive satisfaction from shifting, and flexibility in using the power curve."
] |
the special and general theory of relativity | [
"We know that light moves at the speed *c* (roughly 300000km/s).\n\nSo here's a question for you (that Einstein asked himself): what would you see if you sat on a beam of light and looked into the mirror? Would your reflection disappear? Would it be normal?\n\nHe then thought: what's the speed of light relative to anyway?\n\nHere's the thing: if I run 10m/s, and I'm on a train going at 100m/s, then when I run along the train I'm running 10m/s relative to the train, and 110m/s relative to the tracks. So what is the speed of light relative to?\n\nIn his earlier career he did some experiments [EDIT: He didn't: it was Michelson and Morley, but Einstein knew about the results, and everything. Thanks /u/AramisAthosPorthos for pointing that out.]: can you tell which way the Earth is moving by looking at light inside a sealed box? If the speed of light is measured compared to something in the universe (which they called a luminiferous aether, IIRC) then you should be able to measure it, by seeing that the light hits one side of the box earlier, because the box is moving.\n\nBut there was no change, so Einstein realised that the speed of light isn't relative to anything. No matter what speed you're going at, you must always get the same speed of light.\n\nThis led to the special theory of relativity. He basically said \"what if time is variable and the speed of light is constant?\" and did all the maths to figure out what would happen. It's called \"special relativity\" because it only works in a special case: there is no mass (which causes forces) in it.\n\nGeneral relativity involved a lot more complicated maths to take into account the affects of gravity, which he modelled as a warping of space-time, and took some really, really hard maths to figure out. It's called general relativity because it can be applied to generally any situation. (Actually, it breaks down at quantum-mechanics levels, but that's a different story.)\n\nI think that covers the difference and where they came from. If you want any more details on them, feel free to ask and I'll see what I can get for you."
] |
How do muscles grow? | [
"I hope this answer qualifies as technical, yet simple enough (as I very rarely post here), but the basic idea that I understand is that your muscles rip and tear on a microscopic level when you are working out, and the harder you push those muscles, the more they rip. Hence where the idea comes from that more reps and less weight equal more tone, but more weight and less reps equal more muscle growth.\n\nWhat happens is that following those tiny rips and tears, your muscle heals over itself and essentially stacks on top of itself, healing bigger and stronger than before. The more those muscles are used, kept active and challenged, the more they will continue to build and grow over time.\n\nOther factors go into the growth of muscle as well, such as your nutrition. Protein, fats, etc. also play a factor, as they cause your body to \"feed\" your body and muscles in different ways of varying effectiveness - but I think that's an ELI5 for another day.",
"The enlargement of muscles, known as hypertrophy, is essentially the tearing of muscle fibers being put back together by larger muscle fibers."
] |
What is the role of actual real-life actors in making animated characters? Like Liam Neeson playing Aslan in Narnia? | [
"Could you elaborate your question?\n\nThey are voice actors. They sit in a studio and record their lines. The animators then animate the characters to match the recordings.\n\nThere are some cases (for example Andy Serkis as Gollum in the Lord of the Rings film series) where the voice actors also provides the motions of the character using motion capture technology.",
"For strictly voice-acting: To draw fans \n \nMotion-capture is another story though, such as Andy Serkis in all his roles and Benedict Cumberbatch as Smaug."
] |
Why does the water from my kitchen faucet taste different than the water from my bathroom faucet? Doesn't it come from the same place? | [
"Yes, but the pipes going to one place could have a build up that's changing the taste or the composition of the pipes can be different, i.e. pvc pipes going to your kitchen, but copper pipes to your bathroom."
] |
Precipitation reactions | [
"Why the hell would you need to learn about precipitation rxns in second grade??? I was taught that in the seventh grade IIRC... Please tell me 2nd was a typo???\n\nThe principles are pretty advanced for second graders... \n\nHave you talked about elements and compounds, solutions, solubility?\n\nYou need to be able to talk about solubility before you can actually talk about precipitation reactions, since that is the basic principle. \n\nI am not sure that is something that can be taught to 2nd graders.... \n\nI just asked my mom who teaches 7th grade science... Her students have a hard time learning this in 7th grade, she laughed when I told her about your question. Good luck"
] |
If dark colours absorb more heat, why does light skin burn easier than dark skin? | [
"Two things going on here. First, heat doesn't have anything to do with sunburn, it's all about UV rays. Encountering more UV rays = more sunburn.\n\nHowever, dark skin absorbs more UV rays than pale skin. And in fact that's exactly why it burns less. The pigmented layer absorbs more UV in the upper layers of the skin, shading the cells underneath from UV and preventing burns (because it's the lower, reproducing cells that matter, the upper ones are disposable protection). Just like sitting outside under an opaque black umbrella would shade you more than sitting outside under a translucent white one.",
"In dark skin, there's a a pigment called melanin that absorbs the UV rays (heat has nothing to do with sun burn). In light skin, there is much less melanin, so the UV rays just directly damage the cells because there's nothing else to absorb the rays.."
] |
How the fuck does Facebook know about people I know?! | [
"Your email contacts, your academic/work institutions info you've put, and the friends of your friends.",
"Piggyback question (more an example): \n\nI had a fb acct that only had ~30 people on it. I just used it for work and didn't have any other fb accts. I didn't personally add any address info to that acct, I don't think I provided any info beyond what was required to activate the acct. \n\nWe had a new apartment manager who called me one day from the leasing office land line and I received 1 email from her that was to an email address not associated with my fb acct. Very shortly after these 2 times she contacted me, she showed up on \"people I may know.\" \n\nHow the hell? I immediately deleted that account, which I didn't really use or want anyway. It creeped me the fuck out because I assumed it was due to some weird permission I granted when agreeing to the terms. I've always been curious about what happened there. \n\n**Edit to add that she wasn't friends with anyone else on my page because she was a brand new apartment manager and this was strictly a work acct.",
"Some speculation and good answers in a thread about this a few months ago. \n\n_URL_0_\n\nThink of it this way. It isn't as much about FB knowing who you know, but Facebook already knowing who your friends know. Every data point you give them is another source for them to measure against how you fit into that web."
] |
Why is chickenpox worse as an adult? | [
"It's mostly due to the difference in immune system between a child and an adult. A primary varicella zoster infection (chickenpox) in adulthood is indeed associated with increased risk of complications. Most of these complications are due to the intense response by the adult immune system that comes into contact with the virus for the first time. Children have less active immune systems, but usually active enough to clear the virus - making them immune to it thereafter, and are therefore less likely to develop complications with this particular infection. The same goes to hepatitis A: adults develop jaundice, while children are asymptomatic. \n\nNote: a secondary varicella zoster infection during adulthood is called \"shingles\" and is generally less dangerous than a primary varicella during adulthood, due to the immunity that is already present at the time of the second infection."
] |
How do movies not get uploaded online in HD from movie theater employees before their DVD release? | [
"The theater will be fined a massive amount of money for allowing a leak, the person leaking it will be fined a massive amount of money for uploading it, and they automatically lose their job. This is a combination of copyright law violation and contracts that you sign when taking the job. So the risk are so extremely high that most will not risk it. \n\nThey also have security features such as login codes to open, proprietary file types that need special programs to play, and the rooms operating the projector system requiring special key access at times.",
"The movies are shipped to the theaters in special hard drive enclosures that are tamper-proof and force every access to be logged. The film itself is encrypted in a way that's tied to specific projectors.\n\nIt's not like you can just copy a file over - they've thought this shit through thoroughly and any theater that tries to break the security will get sued to hell and back **and** never get another movie again."
] |
Can defense attorneys 'throw' a case if they know their clients are guilty? | [
"Yes, they could 'throw' a case.\n\nHowever, that's a serious ethics violation which would almost certainly cause disbarment if found out, and not only that, the conviction could then be appealed based on ineffective assistance of counsel (embodied in the 6th amendment).\n\nIf it makes it easier to wrap your head around, think of defense lawyers defending the integrity of the judicial system, not just their client. The idea being, the system must obey all of its own rules in proving that someone is guilty, or else it's a dishonest system and could easily \"prove\" that an innocent person is guilty next time. Defense lawyers are there to help ensure the system stays honest.",
"That would be unethical. In our society, even the guilty are given competent representation. What they can do is seriously suggest that the person take a plea deal. Part of the process requires a good defense or the conviction can be overturned on appeal."
] |
why, when intoxicated, does it feel like everything is spinning when you close your eyes but stops spinning when you open them? | [
"the fluid in your inner ear keeps you orientated and standing upwards, although when your drunk certain functions in your brain don't work as well or as they are meant to. So if you've had a bit too much to drink, your brain might not be able to tell which way is up and which way is down if your inner ears are miscommunicating with your brain. So that's why when you close your eyes it feels like you're falling off the face of the world.",
"Your sensitive inner-ears get affected more-easily, and tell you that you are spinning. But your eyes--while they're open--tell you that you're not.\n\nUnless you get drunker, your brain decides to trust your eyes more."
] |
Why are some fish bones edible, and others are not? | [
"They are small and soft so it does not matter if you swallow them, bigger and harder bones might get stuck in your throat and couse pain"
] |
What's the meaning of the phrase "I've got a bone to pick with you." | [
"If you have a bone to pick with someone, it means they've annoyed or insulted you and you need to talk to them about it.\n\nAccording to the Oxford English Dictionary (via a thread in /r/etymology) \"a bone to pick\" originally meant something that occupies or distracts you (as a dog is occupied by picking at a bone) and somehow morphed into its modern meaning.",
"It's similar to \"I am upset with you about something and want to discuss it\". Depending on the tone of the conversation it might indicate somebody is really really mad at you about something, or just that they have a minor problem they want to talk about, so context is important."
] |
What is different in the brain chemistry that distinguishes thinking about moving my arm and actually moving it? | [
"Thought and motor cortex are separate. So you can think without acting."
] |
Why can't we just taste candy or Sweets and then spit it out to avoid its unhealthy attributes? What makes us swallow it to get satisfaction? | [
"You absolutely could. \n\nBut the fact is that evolution shaped our tastes. That's why fatty foods and sweet foods are so appealing to out taste buds. It is our bodies way of saying \"That has lots of calories and will help us avoid starving.\"\n\nThe 'satisfaction' you feel on swallowing it is simply the body saying \"Good job. Remember that tastes good so we will eat it again if we find it again.\" Rewarding you for fueling it. \n\nYou can see why this system that evolved when we were hunter gatherers to keep us from starving and helping us learn whats best to eat leads to obesity now that we have food options everywhere anytime we want. \n\nFun fact: Most people mistake the bodies thirst craving for being hungry. More often than not if you drink a glass of water when you feel the urge to snack it will go away. Thus helping you lose weight by reducing total calorie intake."
] |
Why are the things that taste the best bad for us? | [
"Let's think about this from an evolutionary perspective. Way back in the day, (like way way way back) humans struggled for food just like every other animal. It was to our species evolutionary advantage to pursue food that would keep us full longer, or provide more energy than other food options. Fats, are 9 calories per gram compared to proteins and carbs that are 4 calories. Humans that preferred fats and craved them, had a higher chance of survival and passing on the fat craving trait. Fast forward to present day where food is plentiful. We are still programmed to eat high calorie foods just in case we won't find food for a week!",
"In the ancestral environment, the one where we evolved, sugar and fat were necessary but scarce nutrients so we evolved the ability to taste them and enjoy those particular things so that we could survive better. \nIn today's first world, sugar and fat are relatively abundant so that we have a basically unlimited supply. Our bodies still have the evolved skill of loving the taste of sugar and fat so we still eat as much as possible if we don't check ourselves. \nPlot twist, food scientists know that we love sugar and fat so they create food that hacks our evolutionary impulses toward sugar and fat for profit."
] |
Why do you see weird colors when you press your eyes? | [
"If I had to take a guess, no expert, just had anatomy and physiology through college, I'd imagine it'd have something to do with the rods and cones in your eyes and the optic nerve. When you push on your eyes, you probably disrupt the innervation action of the rods and cones and it's just trying to adjust back. Just my guess!",
"The mechanism by which your brain sees things is from the electrical signals sent from your eye. When you touch your eye in certain ways it also results in electrical signals being sent to your brain, and to a place that interprets the electrical signals it receives as what you call \"sight\"."
] |
If a movie production has $5,000,000 (estimated) Budget, must some of that money go to the actors? or only movie's production quality? | [
"It has to include equipment, pay for employees (all cast, crew, and extras), fees, *food* on larger productions, constryucting sets, making costume,s all of the makeup artists, set design, sound guy, camera guy, lighting guy, dozens of other specific jobs, and yes, the actors.",
"If it's a Jennifer lopez movie, 85% of that goes to her salary. The remainder is used for her make up. That's why all her movies are obscenely terrible.",
"I work at W.B. Let me be the first to tell you that the idea of a movie REPORTING they spent say $5 million on a film is complete baloney. The tax system is so complicated it would make your head spin. Say they spent $5 million-- does that include tax credits for where the film was shot, who the movie hired, where they hired a certain amount of people, what company did they use to house the actors, did they lose money shipping the film oversees, what if India worked on the film-- who pays those taxes? What if they hedged the money they made against money they spent because they shot the film in Canada. \n\nBottom line- studios report how much they spent, lost, or made depending on what they want the books to show.",
"The movie budget includes for the actors but also all the staff that is needed, equipment, supplies, costumes, stages & sets, etc.\n\nIf the movie is being financed by a major studio, it most likely is bound by union rules by the Screen Actors Guild (SAG), which it is now partnered with the American Federation of Radio and Television Artists (AFRTA) to form SAG-AFTRA.\n\nThere are standardized pay rates and benefits that actors must be paid, so this is figured in to the budget.\n\nThere are also guidelines for a movie that is being produced by an independent filmmaker with a low-budget (which is usually under $2.5 million) that uses actors that are members of SAG-AFTRA.",
"If using Union actors/crew, then the budget must pay at least the minimum required daily rates. Any additional pay is negotiated in individual contracts. Often, actors (or directors) who really believe in a film will negotiate for 'back end' points (a share of the films profit) instead of their normal pay rate. This way, it allows for the film to be made more cheaply and with less risk, which means it's more likely to get picked up for distribution. But the actor avoids de-valuing themselves too. (Sandra Bullock and Tom Hanks are very savvy about this...)",
"Yes, if its a 5 million dollar budget then it will most likely be a union show. This means that most if not all of the actors will be in SAG. SAG has minimum day rates for all performers. The bigger names in the cast will usually negotiate their rates through their agents and managers. Every crew member from the Director of Photography to the the production office to the lowly Production Assistants has a day rate that they are paid and if they are in a union its a set hourly rate, with overtime almost every day of production. Then theres cost for equipment rental location fees etc.",
"There are minimums for films. I know that dude in Captain Phillips got the union minimum for a role of X size or stature at 80K. So some it goes to actors, though acting compensation can get weird with profit and revenue percentages or other things"
] |
What classifies an island as an island? Aren't all continents etc essentially large islands? | [
"While not universally true (especially in the case of Europe who gets to be called its own continent for purely cultural/political reasons) A continent is considered to be the primary landmass on its tectonic plate.\n\nIf you look at a map of tectonic plates: _URL_0_\n\nYou can clearly see that with a few notable exceptions such as Europe and India. In general continents occupy their own tectonic plate. \n\nSo then if you are a landmass that is part of a continent's tectonic plate but is not connected by land to that continent, than you would be an island. Although even this is a fairly tenuous definition.",
"Here's a video by fellow redditor CGP Grey that talks about the definition of islands vs. continents and the differences between them.\r\r_URL_1_"
] |
why does wikipedia ask for donations almost every month? do they really need it to not disappear? | [
"Wikipedia's biggest issue is that their amazing service requires constant overhead. So donations keep it running. Have you ever been inside a server location. That shit is cold, and cold is expensive.",
"Like PBS, it relies on donations for operations. No donations = no money to pay for operations.\n\nEven if you manage to get $1mil in your coffers, does that mean you can stop asking for donations? No. Servers and IT support still costs thousands per month. Staff personnel still costs tens of thousands a month.",
"Yes, servers and network connections cost a lot of money and Wikipedia is not funded by ads. Part of the price you pay when you use a common service is paying for it. You can not give money, and then everything is Facebook - funded by people who want to control your opinions."
] |
How does a water purifier jug work and could you put 3rd world ditch water through one and drink safely? | [
"The passive type of jug won't filter out bacteria and other things that can make you sick. There is a thing called [LifeStraw](_URL_0_) that can do this, but it forces water through a filter as you use it. Something like a reverse osmosis system can make water safe, but that also involves forcing water through a membrane. These things can't be done with just gravity.",
"jugs work by dripping water thru activated carbon. this material traps bad tasting molecules.\n\nconsumer water jugs do NOT filter out all chemical contaminants (like lead) or bacteria. so no you can't run nasty water thru it."
] |
Why people like getting drunk/sloshed/hammered/shit-faced ? | [
"Because only when you're passed out in a puddle of your own vomit can you silence the ennui and existential hum.\n\n\n Source: I'm Irish.",
"For me it was because I didn't have much confidence at parties/it helped me socialize. I liked going to parties to meet people but didn't know how to meet people without drinking. I over drank because of the availability of alcohol and the length of drinking.",
"Who has been giving you alcohol!? TO YOUR ROOM! NOW!",
"If you're regularly throwing up, you're doing it wrong. Pace yourself, know your limits, and be sure to have a glass of water here and there. And definitely do not drink on an empty stomach",
"Because my mum is at work on Christmas day and I'm stuck in the house with my mums husband who hates me.",
"ages < 30: It's the \"cool\" thing to do.\n\nages > 30: Marriage."
] |
What happens when a "too-big-to-fail" bank goes bankrupt. | [
"> These assets wouldn't simply evaporate into the air\n\nThat's exactly what they'd do. That's what it means for a bank to fail—it means that they simply do not have the assets to cover all their liabilities. You can have a million dollars in your account according to a ledger book or a computer screen. But if the bank doesn't have that money, they just don't have that money. \n\nSay you deposit your money in Bank X. Bank X loans that money out to people who want to buy Beanie Babies. It's 1998, and Bank X knows that Beanie Babies are worth a lot of money. So even though they've given out a lot of money, they get to take the Beanie Babies back if the people don't make their monthly payments. So whether it's cash or Beanie Babies, the bank is gonna get something that's worth a lot of money. \n\nBut wait. It's 2000 now. Nobody gives a shit about Beanie Babies anymore. Everyone wakes up and realizes they were way, way overpriced. Now they're worthless. And so are those loans Bank X gave out. The people who bought the Beanie Babies aren't going to keep paying every month for something they don't give a shit about. And the bank is more than welcome to take those Beanie Babies back, but what's that even going to get them? They're not worth anything. \n \nSo, now you go into Bank X to try to withdraw your money. But the problem is they already gave all that money to the people who wanted to buy Beanie Babies. They were hoping to make back that money and then some. But as we just discussed, that didn't happen. So now the money is just gone. Maybe the government will step in and try to save you because it was \"unfair.\" But that's another matter. The money is just gone, and if you want it back, you're gonna have to get it from somewhere else.",
"The government tries to intervene, but in the end, if they can't recall enough loans and give enough savings back, they just kersplode and so does the money. Before the 30s the government didn't try to intervene, so that's why the economy collapsed so hard in the Great Depression (people just didn't trust banks anymore).\n\nThis is bad for obvious reasons so they've taken some approaches to prevent this (like the Federal Reserve coming around every once in a while to make sure they aren't stretching themselves thin) and just straight up insuring some larger banks like in the bailout. As well, all deposits with registered banks are protected up to $250k in case of bankruptcy by the FDIC, which shouldn't be a problem for 95% of Americans and the remaining 5% probably have financial advisors to invest the excess (which is a better idea anyways)."
] |
Why is the recent Apple vs. FBI encryption debate relevant years after the Snowden leaks (2013), passage of the PATRIOT Act (2001), and the ECHELON revelations (1988)? | [
"The Apple debate has nothing to do with the government's right to get the information. They had a warrant from a judge, who has way more certainty than probable cause to believe that the phone was used by someone who committed a crime. They also had permission from the owner of the phone (the guy's employer) to access it.\n\nIt's about as clear as it can be that the government has a right to that phone. What's also clear is that if Apple had a way to get into the phone, they would have to provide that to the FBI. Since Apple didn't have a way to get in, they didn't have anything to give to the FBI. They also did not want to make a tool to bypass their own security measures (reasonably in my opinion, since there's no way to restrict the use of that tool to law enforcement officials with a warrant). The FBI wanted to force them to make such a thing. And whether or not the FBI could force that was being debated.\n\nThe most relevant law concerning this- the Communications Assistance for Law Enforcement Act (CALEA) says that the FBI can't force Apple to do this. So the FBI tried to interpret a very old law, passed by the first Congress, as \"we can force anyone to do anything as long as we get a judge to sign off on it\". Apple, along with every other company in the country, was rather frightened of the idea that judges could make any one do any thing with just a signature and without a hearing. So they refused to comply."
] |
Why has the Mars Rover Opportunity's Lithium Ion Battery Lasted 11+ Years and the one in My Cell Phone/Laptop/Tablet Dies in Less Than 2? | [
"NASA requirements lean toward the 'overengineered' side (for good reason - if something goes wrong you can't replace it). The battery in your phone is more from the \"make it cheaper, they can always buy another battery\" school of engineering.\n\n(Just to clarify, I am not being cynical about phone/laptop batteries. Most people - me included - would rather not pay something like 100 times as much for a battery that is able to withstand operating on Mars and lasts several times longer.)",
"The battery in your phone was primarily designed to be cheap, small, and as long lasting as possible likely in that order. This R & D was likely performed by some underpaid engineers in a corporate structure.\n\nOpportunity's battery is much larger and was designed to last as long as possible in space by a team of government funded engineers that could be considered among the brightest on the planet.",
"I've not been able to find data on this, but one reason *could* be that they keep the battery cool. \n\n[Heat kills lithium ion batteries](_URL_0_) (table 3: after 1 year a 100% charged battery kept at 0 degrees C has 94% its capacity remaining, vs 65% when kept at 40 degrees C). \n\nYour cell phone / laptop (while being used) gets quite hot, while on Mars it's so damn cold you have a hard time keeping everything warm enough to even function.\n\nAnother factor could be that the rovers trickle charge their battery from solar panels, while cell-phones try to charge as fast as possible which makes the battery run hotter and itself reduces the lifetime of the battery.",
"In addition to what's been mentioned, it depends to what voltage the lithium ion batteries are charged.\n\nIf a Li ion battery is charged to its max voltage every charge, then it takes longer to discharge, but wears out more quickly. However, if the same battery is only charged to 75% every time, then it will last for many more charge cycles.\n\nPut it another way, lets say your phone battery lasts for one full day on 100% charge. Use it every day and get ~2 years of use before the charge doesn't hold up well. OR, only charge it to 50% every day, so your phone dies at lunchtime every day, but you'll be able to charge it to 50% for 20 years! \n\nOne more option, and this is closer to what NASA does, make the battery twice as big and only charge it to 50%. Now your phone will last all day AND you can recharge it for 20 years!",
"The Rover battery assembly includes two batteries each with its own controller which monitors the status and controls the performance of each cell. They have far outlasted even the designer's hopes: they were designed for a 90-day mission and expected to last up to 3 years.\n_URL_1_",
"Quality of the product and a solar panel back-up. Imagine the difference between your car battery and a cellphone battery. One is bigger, they are designed for different tasks, and one is constantly being recharged.",
"Your phone Battery didn't cost millions of dollars.",
"Several reasons. Different battery design which increases the weight and volume but wears out slower. For the rover, weight is important but volume not so much. Most battery powered things are designed to minimize volume and weight at the expense of longevity.\n\nThe other important reason is the system is likely designed to keep charge within a small window of what is technically possible. Lithium ion batteries last ungodly amounts of charge cycles as long as the chage is kept in a range between roughly 30-70%. The same technique is used to greatly extend the life of the batteries in hybrid vehicles.",
"The Opportunity didn't spend 60% of its time streaming porn.",
"I don't buy /u/hangnail1961's response at all. They don't use any old battery for a mission like this. There's completely different requirements. It doesn't have to fit in your pocket, they can't ship back a defective battery from mars, and cost isn't much of a factor. They probably used a battery design that's extremely rugged. I doubt the battery designers wanted to be the ones that made the mission stop at day 91.\n\n\"90 days\" for a mission doesn't mean every component was designed for 90 days either. If that were the case, the mission would have probably lasted 45 days. To be 95% sure all components last 90 days you need to design each component for a much longer duration.",
"Three main reasons I can think of:\n\n* Li-ion batteries last much, much longer in cold weather\n* Low charge and discharge rates are much easier on the battery\n* NASA has a huge budget and likely used the very best tech available",
"Bigger, more expensive, better build with ideal enviroment and case protection million dollar NASA battery last longer than consumer 1700 mAh random-usb-charges, heat-induced-from-cpu/gpu-running-angry-birds-in-background and back-pocket-pressure, 4mm thick china-made-chemistry called phone battery. \n\n~10 times longer, in fact (li-ion fanatic here).",
"Things are intended to be replaced so the demand for the item can continue and so can the business. I kinda think that many items could be made to last, but companies design them to break early.",
"You don't have solar panels helping recharge your phone constantly."
] |
Why some bugs fly to lights. | [
"Navigating at night is hard. You can't really see anything, especially not distant landmarks.\n\nOnce upon a time, the most reliable \"landmark\" was the moon. Sure, the moon moves in the sky throughout the night, but if you just wanted to forage by covering a large area, following the moon (without moving higher up the atmosphere) is a good rule of thumb.\n\nBut now we have artificial lights. Insects think they are the moon, and fly towards them."
] |
Why is sales tax in the US excluded from the list price? | [
"Because every state has a different tax rate on goods, so that would make putting tax into the price a little difficult",
"It's a principle of transparency, letting the citizen know exactly what they are paying for the product and how much they are paying in taxes, which is something important as transparency goes for the government.\n\nHere in Brazil everything is pretaxed, so when you pay R$ 3,09 (3.09 to some) for a liter of gas, you have no idea how much of that is in taxes. Lately people have spun a great movement for commerce to at least display separately the amount due in taxes in the price tags. And I believe that's important because more than 50% of that R$ 3,09 is taxes, so when you get shitty services from the government, you know exactly how much they are stealing from you.",
"Can anyone give the arguments for and against unifying sales tax across the US?\n\nI know in Australia, GST is 10% nationwide for most items (I think some things are tax free, and are indicated as such), so tax is included in the final price and not really thought of. So a $7 Subway is exactly $7 in WA and exactly $7 in NSW. ($6.36 item and $0.63 GST, but we just see it s $7)\n\n(And please excuse me if I've been ignorant and not seen the really obvious answer!)",
"It also allows companies to advertise an item at the same price nationwide (regardless of the varying state taxes), and not have to worry about the actual final price."
] |
Why does a beer on tap almost always taste better than it does from a bottle? | [
"Probably because the keg has been better handled than the cases of beer have, and because bottles are not actually the best packages for beer. Light passes through the glass and can cause skunking, and oxygen can sneak in through the plastic seal in the crown, causing staling. Kegs are generally stored cold, and of course are completely opaque and are much more resistant to oxygen ingress.",
"Bottled beer is generally pasteurized (treated with high heat to kill germs) while draught beer from a keg has not. The heat can change the flavor slightly.\n\nAlso, since most of taste is smell, drinking from an open glass rather than a bottle gives you a bigger experience of the flavor."
] |
What is the significance of Jamaican Bobsled team qualifies for the Olympics? | [
"Let me tell you about a man...a great man...a man who helped the underdogs...a man who traveled by many forms...a man who loved his nieces and nephew. A man who left this world too early. \n\nThat mans name was John Candy.",
"Kids these days...\n\nಠ_ಠ\n\nJamaica did bobsled in the Olympics before... despite massive opposition they came in last"
] |
Is it possible to build up an immunity to poisons both naturally occurring and man-made? | [
"Sort of. It's called [Mithridatism](_URL_0_), after a Roman-era king of Pontus (northern modern Turkey). But you can only do it with certain poisons; others just build up in your body until they kill you.",
"No, not really.\n\n\"Immunity\" to toxins doesn't really happen. You can become more tolerant, but there will always be a deadly dose. There are even deadly doses of things we wouldn't normally consider toxic, like water.",
"Yes. I personally have built an immunity to iocane powder. Very useful in situations like when short, mad Sicilians kidnap your True Love.",
"I pretty much agree with everyone here. The biology of how it works (in a nutshell) is this:\n\nSeveral organs are tasked with clearing poisons from the body, but the main one is probably the liver. (Let's just talk about the liver for simplicity.)\n\nYour liver cells have receptors (sort of \"feelers\") on their surface to detect certain toxins. When they are detected, the liver cells respond by producing enzymes designed to break down that particular toxin. If the liver is constantly being exposed to a toxin (like alcohol), it will constantly have a supply of the enzymes that get rid of it on hand. If that's the case, you will need more alcohol to have the same effect. That's what tolerance is.\n\nOver time, though the cells become overworked, and exhausted, and die. Liver cells are also particularly sensitive to the toxic effects of alcohol. So in the long run you can generally sustain your ability to drink alcohol longer than you can sustain your ability to rid your body of it. Most toxins have a similar critical point. \n\nNow the question of natural vs man-made toxins is interesting, but the answer is that it doesn't necessarily matter. The human body only has so many vulnerabilities that poisons can exploit. Don't get me wrong, there are plenty, but not infinitely many. Nature has done a pretty thorough job of devising ways to kill us. I'm not sure humans have invented a totally novel toxin, so much as tweaked and improved existing natural ones, like \" here's a version of venom that does the same thing, just much faster! It kills you long before your body can mount a defense.\" So, in those cases can you develop immunity? Theoretically? Sure. But in practice... that'd be hard to do"
] |
How do devices know the amount of charge left in a battery? | [
"I think the best way to explain this is through an analogy. Imagine you have two tanks of water. One has a lot of water and the other is empty. If you were to connect a pipe running from the bottom of one tank to the bottom of the other, water would flow through the pipe until both tanks have the same level of water. If you were to put a water wheel in the path of the water flowing through the pipe, you could use the flow of the water to do work.\n\nBatteries work the same way. They create a \"potential difference\" between the terminals. This is a fancy way of saying one terminal has a lot more electrons than the other, just like the tank with more water. If you were to connect the terminals with a \"pipe\" (or in this case a wire) that would allow electrons to flow to the terminal with little electrons, they would. We can also use that flow of electrons to do work for us as they go from one terminal to another, such as power a screen.\n\nWe can estimate how much energy is left in a battery the same way we can estimate how much more water is left in the full tank. As the amount of water-difference between the tanks decreases, so will the speed at which the water flows through the pipe and consequently the speed at which the water wheel spins. Similarly, as the amount of potential-difference between the terminals of a battery decreases, so does the current of electrons and consequently, the amount of work that current can do. Devices can measure that decrease in work and use that to estimate the amount of potential difference left in the battery",
"The Voltage of a battery depends on the charge. A five voltage battery may start with 5.1 Volt and slowly go down. When you're at 4.9 volt you'll know the battery is rather empty.\n\nI'm not sure if that is the case for all modern Rechargeable batteries. They might have special measuring and charging chips included."
] |
Why are my muscles sore after jumping in cold water? | [
"From what I understand, our bodies defenses against hypothermia is to shiver. This involves involuntary muscle contractions to generate heat. These muscles contractions still can cause muscle soreness just like working out.",
"Many athletes actually use a cold bath post workout to *alleviate* soreness. The idea is that the cold constricts blood vessels and reduces swelling, then afterwards the blood can flow back and speed recovery. This is especially popular amongst competitive cyclists. \n\nIf your muscles are sore after cold exposure, maybe they're just stiff and lacking blood flow. I've noticed it's hard to pedal after a dip in a cool lake midway through a ride. As the muscles rewarm, they regain their mobility.",
"You probably just contract all your muscles as you hit the water, same as being hit by a car and feeling sore.\n\nSource: am hit by car once"
] |
why do we like watching the same TV show or movie over and over again? | [
"Our brains like familiar things. Something we already have seen is easier to get into than something brand new because it requires less attention and effort from our brain. It's also sometimes good watching a TV show knowing the ending (eg Black Mirror, Lost) as we can pick up on foreshadowing or minor details.",
"to relive the emotions felt the first viewing. sometimes a person feels sad but cannot cry so watches a sad movie to bring it on. likewise, you need a good laugh to bring you out of a funk.",
"It's a matter of taste. Not everybody does like watching the same thing over and over again. I don't. I can't stand watching the same film twice because I already know what's going to happen. Some people do. We like what we like.",
"Well it's a loaded question to begin with. Frankly, I can't stand rewatching a movie or show I've seen before."
] |
why do the French have an abstain vote instead of people physically restraining from voting. [Other] | [
"It's like a protest vote. I live in Nevada where we are allowed to vote \"none of the above.\"\n\nIf \"none of the above\" wins, the candidate with the most votes still wins. It doesn't affect anything here.",
"Abstain is a different thing from simply \"not voting.\"\n\nIf I don't vote, it could mean any number of things. Maybe I don't care enough about the election, maybe I was busy and didn't make it to the polls, maybe I forgot which day it was.\n\n\"Abstain\" means \"I don't like any of these options enough to vote for one.\" So it sends a clearer message than simply not voting - the person is clearly interested enough to vote and is choosing not to."
] |
Why The Beatles broke up? | [
"It wasn't that they were mad at each other, although if you spend enough time with someone they can start to bother you, right? But you can still love someone who bothers you, right? So it wasn't really about that at all...\n\nRemember that toy you used to have when you were three, and how you got bigger and smarter and didn't need it anymore, how it seems like a baby toy now, compared to the toys you have now?\n\nThat's what's called \"outgrowing.\" At some point, you get used to most of the things in life that were once fascinating to you. But it's not sad when it happens, because you grew, which is good, and you always think happy thoughts about those things later on, right? Even though you don't need them anymore?\n\nThe beatles were four really good musicians that really brought out the best in each other. They all wanted to make really good music, and they realized that the best music they could possibly make was the music they made together. But then after a while, they didn't need each other so much anymore. They had all discovered new things on their own. Just like when you discover a new toy, you don't always NEED the old ones anymore. Even if you remember them as being the best toys ever, you wouldn't really want to play with them too much now, right? They're still there, you can go back and play with them if you want to, but right now there's new things to learn and explore. \n\nSo just like you and your old toys, each of the beatles discovered new things they wanted to explore. So they all agreed to spend some time doing that, and then they discovered new things after that, and new things after that.",
"They didn't so much as 'break up' as they just started doing different things by themselves, or with other people. Eventually they just weren't doing things as 'The Beatles' anymore and decided to make it official.\n\nPaul said that they broke up because of: \"Personal differences, business differences, musical differences, but most of all because I have a better time with my family.\""
] |
- Why do phones not require cooling vents but other small appliances do? | [
"Phones lack a cooling system because there's no room for that. It takes up way too much space for a pocket-size device. If that wasn't an issue, phones would've had vents.\n\nBesides, phones don't work as hard as other computers do. They are weaker, so they produce less heat. Still, they can get hot sometimes, especially during charging, and there is nothing we can do about it.\n\nPhones cool by radiating heat away and through conduction - passing heat into the surrounding air/skin.",
"Phones are very specifically engineered to be both low heat and to have passive cooling systems to dissipate that heat. It take a lot of engineering to do this properly, but it is necessary for a device that is meant to be carried and hand held.\n\nOther appliances _could_ have systems like this, but there is no real need for them. They can be large enough to have larger and more active cooling systems, which are less difficult to engineer and less costly to implement. Since there is no real benefit to making these other appliances smaller, they use the easier/cheaper cooling tech.",
"How much additional cooling a given component needs depends on how much heat it releases during use, on what temperature it can tolerate internally before it gets damaged, and on what equilibrium temperature the surrounding environment reaches during use.\n\nIn a phone, if a part is getting too hot, you only really have a couple options: \n\nmodify the design or operating conditions so it makes less heat (also improves battery life, but can negatively impact performance)\n\nImprove thermal conductivity between the part and the outside of the phone. (for example, you could switch from a plastic frame to an aluminum one)",
"Phones are typically underclocked to reduce power consumption and heat generation. And they start with low power parts to begin with. Heat is removed just by letting it passively radiate from the phone."
] |
Why are oil prices so shockingly low? | [
"Someone feel free to correct me if I'm wrong, but my understanding is the Middle East put out so much supply to try and put US companies out of business which if successful they would then jack prices up and get money to themselves.",
"It's all politics. What looks to be the main reason is that Saudi Arabia is losing market share in the oil game so they are distributing it in massive quantities in order to regain market share. So economically speaking it is supply and demand. They are flooding the market which increases supply causing the equilibrium price to drop, but it's based off of politics.",
"Do you think it also has anything to do with the US trying to isolate Iran?",
"_URL_0_\n\nthis is a pretty goos documentary on the whole thing."
] |
If the inside of my microwave is made of metal, why is it bad to put metallic objects in it? | [
"The metal interior of the oven is grounded. It does pick up a charge from the microwaves, but the charge is dissipated to ground, and so does not arc. Your fork, or the foil on your plate, are not grounded, and thus the charge can build up until it is strong enough to arc to a grounded panel.",
"Another thing to note is that not all metalic objects will spark. its only pointy things like forks, tin foil and knifes (depending on the knife). Spoons are usually fine in a microwave as they are rounded. Thats also why those chef boyarde microwavable things can have [metal lips on them] (_URL_0_)."
] |
Why do we lack the instincts our ancestors had, e.g. telling you which foods are poisonous | [
"We still have them. Ever gone \"EW\" from spoiled food and decided not to eat it? Ever smelled something horrible and realized that it wasn't edible? \n\nThe issue is that we've realized that there's a lot more items out there can that kill us, and notice it. Our ancestors would have just died from eating it, and then warned the surviving descendants to stay away from it.",
"We don't lack it. It's not like they had some magical ability to tell if something was poisonous by looking at it. Our bodies almost make us vomit if we smell rotten meat - that's the ability!"
] |
Why do we wake up early when we don't have to but tend to wake up late when we need to be up? | [
"The simple answer is stress causes this.\n\nBy setting a schedule your body will fall into a rhythm. After a while you don't really need the alarm at all. However as we know our natural rythems get disturbed occasionally. When we must get up we are creating stress that is easiest to avoid by doing nothing and that is what we want to do (avoid stress). On the weekend you don't have stress to avoid and your body is doing its thing.\n\nA sign of depression (just one of the signs) is oversleeping. Your mind allowing your body to avoid the stress of life every chance you get. Feel good that you feel awake when you don't have to. Your life is manageable to you.",
"I know the true answer. we are in the computer. you are people born and living in the computer. just some program, like a demon, bother you.",
"I was actually wondering the same thing not too long ago when I was on holiday. \nWe have just been on a cruise with endless activities and I found myself waking up at around 5am every morning. I wasn't actually able to do anything but watch tv until 8am but I think it is just the fact of waking up to something you really enjoy. After coming back, I have had a boat load of university assignments to finish, and I find myself waking up 9-10am. I usually get up at around 8am, but knowing that I am going to be sitting by a computer all day doing work, I find my bed just all that more comfortable."
] |
Why do tech/software companies stay in the US when they are demanded to include backdoors by the US government? Can't tech companies just develop and release their products overseas, out of reach of the US government's influence? | [
"The short answer is that it's not just the US government pushing to include \"backdoors.\" Tech companies could move to a country without these laws, but places like the US could restrict or prohibit them from selling their products in the US.\n\nThe better option is to follow Apple's example and refuse to build the backdoors.",
"1) These demands would be required of any company selling in the US, not working in the US. The US market is too big to give up. \n\n2) The US government is not the only government asking for these backdoors.",
"Ask Microsoft how well being an American company worked in getting them out of an EU antitrust case. You can't just not be based in a country in order to do business there without following their laws."
] |
with such an important vote like appointing a supreme court nomine, why is the senate floor so empty? | [
"Well, actually, that's not their one job. They also have to meet with people, work on legislation, and so on.\n\nMany of the Senators may be in their offices. When an important vote is called, they will come to the floor to vote. They can get from their offices to the floor in just a few minutes."
] |
If you put tires on your car that are larger than the ones from the factory, would you actually be going slower than the reading on your speedometer? | [
"No, you'll actually be going faster. The speed is calculated based on the OEM tire size, whereas if you put a larger tire on, there is more circumference so the hub will spin slower, yet will be traveling the same speed.\n\nYou can have it recalibrated fairly cheaply.",
"Example: Your car comes with factory-installed tires that are 21.8 inches in diameter. That means the circumference of each tire is 68.5 inches. Now let’s say you want to replace the stock tires with new tires that are 24.6 inches in diameter. Each new tire has a circumference of 77.3 inches, which means it travels almost 10 inches farther with each complete revolution. This has a tremendous affect on your speedometer, which will now indicate a speed that is too slow by almost 13 percent. When your speedometer reads 60 miles per hour, your car will actually be traveling 67.7 miles per hour!\n\n[source ](_URL_0_)"
] |
How does bugspray kills bugs? | [
"Bugspray is actually a chemical weapon. As in it shuts down biological functions bugs need to stay alive, like forgetting how to breathe for example. It can also cause military chemical weapons detection gear to register false positives."
] |
The FairTax plan | [
"The fair tax is regressive but it offers up citizens a prebate to offset their costs. \n\nBenefits \n\n* You are taxing consumption instead of production so it's seen as a more just system. \n* The stress on working household would be lessened since exemptions can be made for food or necessities. \n\nDisadvantages \n\n* This tax would stack with other state taxes so in Washington state for example a 35 percent tax would be affixed to most goods. \n* The majority of our economy's activity is consumption so it would quickly stifle growth by discouraging consumption, especially on big ticket items like auto and home purchases. \n* Once the funds accorded to you are spend you are left in the uncomfortable position of having to pay a tax of between 1/4 and 1/3 of the purchase price. \n\n[Summary of the Idea](_URL_0_)"
] |
What is slowing down our internet speeds? | [
"ISP backbones tend to oversell their bandwidth, because not everyone is using their maximum allocation all the time, so there would be unused potential that isn't generating profits. This is how your neighbors can slow you down. Much of your connection is just you and your wire until you get to some shared trunk.\n\nSecond, cheap home equipment can be a significant slowdown; I'd say even the equipment you're renting from your ISP can be crap that can't deliver. Buying something good will require research beyond the scope of this post.\n\nThird, there are slow downs caused by the routing protocols as well as a fundamental design flaw in our network infrastructure. I mean, it takes time to process a packet at each hop, but this shouldn't be terribly significant. But the fundamental flaw is buffer bloat. Look it up, it was identified just a couple years ago. Basically, our routing protocols control data rates and latency by responding to dropped packets; if you're sending more than the receiving end can handle, you slow down. Well, routing equipment these days have a lot of ram, so if they can't send as fast as they're receiving your data, they're just going to buffer your data packets at full speed until the buffer maxes out, then they drop packets. You respond by slowing down, the buffer clears out just a bit, and you start sending at full speed again, until the buffer maxes out. It's dip, after dip, after dip, after dip... And this KILLS performance. The current best way to fix it is to reduce the RAM in the equipment, but no manufacturer is going to sell their newest HyperFast Router, \"Now with LESS RAM!!!\"\n\nOur routing protocols were designed this way because the early internet didn't have massive buffers, hardware was expensive and so it was out of necessity. We now need new protocols that can take this buffering into account, and they're working on it."
] |
If a computer has a GPU, why would reducing GUI effects impact performance? | [
"The program has to be written to take advantage of that hardware. The Windows GUI, for example, being your desktop - that rendering code was written before hardware acceleration was ubiquitous. All of your windows, button, and icons are all rendered \"in software\", aka on your CPU. And your CPU isn't designed specifically for rendering, so reducing effects improves performance.\n\nAnd some of the big costs in rendering has to do with blending. Transparency is expensive, as can be anti-aliasing. And Windows desktop rendering is done on a single thread, so no matter how many CPUs or cores you have, it won't have much of an impact. Further, rendering happens on the \"main thread\", which, I believe, is also responsible for IO if memory serves me... When you're busy rendering, there's an event queue of everything you've clicked or typed that's waiting to be processed; not until the screen is refreshed. Many desktop apps are written to be single threaded, so they only execute on one core, so everything the program does happens in sequence. If rendering the window is going to take a long time, everything else in the queue is waiting to get processed. A programmer using C or C++ as their programming language has to write multi threading code themselves to take advantage of it.\n\nMicrosoft would have to rewrite that whole software layer to take advantage of a GPU, and they're not going to do that, because they're insane about backwards compatibility. Instead, they wrote a new GUI layer that developers can use going forward. Migration is always slow. Microsoft will probably keep support for their software rendered GUI for decades before they even mark it as deprecated, and then decades more before they remove its availability.",
"If you're talking about Windows Vista and beyond.\n\n**Disabling visual effects doesn't increase performance**\n\nMore detailed explanation is here:\n\n_URL_0_\n\nELI5:\n\nThis checkbox just switches off new system (GPU rendering) and brings back XP CPU rendering, because some software can't use new system. Starting from Windows Vista GUI is rendered on GPU(actually it's pretty complicated for compatibility reasons, old programs still use CPU rendering, and resulted bitmap is passed to GPU for composition and rendering).",
"Not all programs are written as such. To send data to a GPU directly, requires a whole lot of programming."
] |
What happens if you don't pay your US Federal income tax? | [
"I'm no expert on Constitutional Law, but where did you hear that the US income tax has no basis in law and is unconstitutional? The entire purpose of the [16th amendment](_URL_0_) was to make the income tax permanent. It was ratified almost a century ago.\n\nPeople aren't tricked into paying it for no reason, you can go to jail for tax evasion.\n\nYour income tax is not necessarily deducted from your paycheck, it depends on your withholding allowance.",
"The \"don't have to pay taxes\" thing is a myth, perpetuated by people who want to sell you a book on how not to pay your taxes.\n\nPeople who follow their advice, and often the authors themselves, can face serious consequences, including jail time.",
"The wiki article _URL_1_ describes all the wacky ideas people get that taxes aren't legal. Summary of article: your taxes are legal, and courts take a dim view of you trying to avoid them.\n\nIf you don't pay your taxes, the IRS levies a fine against you and starts charging you interest on the tax you haven't paid, just like if you don't pay your credit card. The difference is if you don't pay enough for your credit card, it can get cancelled, but if you don't pay your taxes, you can go to jail.\n\nIncome tax can be and frequently is deducted from your paycheck per the data on your W-4, but it doesn't have to be - you can set it up so you pay quarterly yourself instead, but that's a pain to keep track of.",
"It is not illegal to not pay taxes. It is illegal not to file. Having said that the IRS will get their money if you owe it unless you live underground."
] |
Why does my employer require a voided personal check in order to setup direct deposit? | [
"Your banks routing number and your account number as well as your name exactly as it is written on your account are all printed on the check. That is the information they need to set up direct deposit. With the check they can be sure there are no mistakes."
] |
Why are the insides of Ovens Dark and Not Metallic or Mirror Like? | [
"How often do you polish the inside of your oven? I suspect a big reason would be just to keep the interior from quickly looking horrible.",
"The inside walls of an oven are at the same temperature as the interior of the oven (usually hotter, actually). So any heat they do absorb is just going to be re-emitted back into the oven, even if they are not shiny.\n\nMuch of the heat to the interior actually comes from the inside walls in the first place. Most ovens have the heating element heat the floor of the oven (not heating the interior air directly). The floor conducts that heat to the walls, and then the floor and walls radiate that heat into the interior cavity. If the walls where shiny, they would not radiate as well. That is one of the symmetries in physics. If you reflect a wavelength when it hits your surface rather than absorbing it, then you also \"internally reflect\" that wavelength rather than emitting it.\n\nYou could probably come up with a coating that is shiny in the visible range, but \"black\" in the IR range. But 1) why bother? and 2) the insides of ovens are dirty, why would you want to make that more obvious than it already is?",
"Modern ovens heat via convection aided via a small fan somewhere in the oven. Radiation from the walls and heating elements and reflection from the walls. But a oven also has to be designed to withstand normal use, and it's heating cycles. Protect the surrounding cabinetry from the heat and any cleaning chemicals that may be used.\n\nThere might be materials that do one or two jobs better at a certain price point. This would be a good question for a materials engineer"
] |
Why does metal react so violently when microwaved? | [
"The way microwaves work is through jiggling charged/polar particles in your food (the water primarily). This jiggling increases their temperature and that heats up the rest of your food. That's why you can't heat oil as easily as you can water.\n\nHowever, metals like iron are *great* conductors of electrons. What makes them good conductors is a little complicated but basically, the reason is that they have a soup of electrons moving from atom to atom with almost 0 energy needed to move an electron from one atom to another. \n\nThus when the microwave jiggles these electrons, rather than giving energy to the atom, it gives it to the electron which zips around in the soup. The amount of energy given to the soup can get high enough to bypass the natural insulation of the air and cause electrons to jump from the metal and rip through the air. This is called a spark and is basically what happens during a lightning strike."
] |
Derivatives (in financial markets) and how people make money off of them | [
"Derivatives are kind of what they sound like, products derived from the value of other things.\n\nA very common type of Derivative is the Future.\n\nA Wheat Farmer is growing 50 tons of wheat, but it won't be harvested until 3 months from now, but he wants to lock in the price he's going to get for it now. \nSo he'll use a Future to agree to Sell 50 tons of wheat at $10,000 a ton in 3 months. \nA Speculator may take the other end of that agreement. Sally to Speculator will agree to buy that Wheat at $10k/ton in 3 months. Sally is predicting that Wheat prices will rise in the mean time, and that she'll be able to sell her end of that contract for more money before those 3 months are up.\n\nIf the going rate of Wheat in 3 months is actually $12,000/ton, then Sally finds another person, either another speculator, or a person who actually needs wheat for something, and Sally transfers her contract to them. \n\nA person would be willing to pay almost $2,000 to get Sally's ability to pay $10,000 instead of $12,000. \n\nSo Sally ends up making $2,000 per ton on that price increase.\n\nThe part that makes Derivatives so good to potentially make money from, is the amount you have to put up as security is very small compared to hold much of the product you have control over. \n\nA contract on something like Crude Oil is usually 1,000 barrels of Oil, you might only have to put up about $3,000 to enter an Oil contract, controlling almost $70,000 worth of oil.\n\nIn some more extreme cases, like currencies or T-bills, you can put up about $400 to control over $1 million worth of T-bills, or $1,000 to control $1 million of USD Currency.\n\nThe most common place way to think of derivatives is like having a coupon. If you're at the store and have a $1 off coupon on Cereal, but you don't want cereal, and someone else does want Cereal, but doesn't have that coupon... that person should be willing to pay you almost $1 to use your coupon.\n\nDerivatives can be a very fast way to both gain and lose money, but they can also be used by businesses and people to hedge their bets and reduce risk on the prices of products they produce or consume. \n\nEDIT: I should say the actual transfer of money of a futures market is more complicated than I represented above, money is actually transferred daily, not a lump sum when someone 'buys' or 'sells' the contract, its just a little easier to think of that way than worry about daily mark-to-market."
] |
How did the American accent come about? | [
"It's not so much that Americans developed a distinct accent, but rather that speech on both sides of the Atlantic changed significantly, with both sides diverging quite a bit from what they had sounded like earlier on. This process is still happening, with accents on the Canadian and US sides of the great lakes undergoing vowel shifts at this very moment, and in opposite directions; Canadian and US accents are actually becoming less similar, even among people in the niagara region who live a few km apart.\n\nWhy? We don't really understand this process at all well. The key thing relevant to your question though is that accents change a lot, that distance and separation make this process easier and more likely, and that neither English nor an American speakers sound much like their 16th century forebears.",
"This article provides some explanation. What's interesting is that medieval English is closer to American English than contemporary British English.\n\n_URL_0_"
] |
Why do The Miranda Rights state that anything you say can "and will" be used against you. If something's not incriminating why would it be used against you? Why would cops be forced to admit this up front? | [
"Its just to put emphasis on the fact that *they will* use any and all evidence against you that they can, including anything you say or do.",
"The rights are telling you, anything you say , whether you think it is incriminating or not, can be used against you by someone following the letter of the law. This is the warning part. And if it can, it WILL be used, they won't ignore anything. This is the assurance of prosecution part. \n\nIf you are not a lawyer, this story may help you.\n\nA little bird finally grew its wings and decided it was time...it jumped into the air overjoyed as it merrily flapped it's wings.\n\nBut the air was cold , and the little birdy froze and passed out, hurtling towards the ground and landing in a pile of fresh cowdung. \n\nThankfully, the warmth of the fresh cow crap revived the little birdie...and it started chirping loudly trying to free itself from the goo.\n\nA fox heard its chirps, and quickly pounced eating up the little birdie. \n\nWhat lesson did you learn?\n\n1. What you think is good for you, like flying, may not be.\n\n2. What you think is bad for you, like landing in cowdung, may not be.\n\n3. When in deep shit, KEEP YOUR MOUTH SHUT!",
"It's a way of saying, Shut the fuck up before you say something your gonna regret.",
"If they don't add the \"and will be used quaint you\" part, then they could lie and day they won't. \"I just want you to tell us what happened, I'm not going to use anything against you\" and then when you admit to being an accessory to murder they arrest you. This part of the Miranda rights is to remind the person that the police are trying to build a case, not necessarily to help you.\n\nEvery part of the Miranda rights is detrimental to police, it doesn't help them if the subject calls in a lawyer or pleads the fifth. It's to protect the ignorant from being taken advantage of.",
"It \"can\" be used against you and if it is incriminating it \"will\" be used against you. Something that is not incriminating will not be used. It is best to use the rights the 5th amendment gives you and refuse to say anything or answer any questions until you have an attorney."
] |
Why is it when you rewind VHS tapes they lose their quality over time? | [
"Since rewinding needs to be done for each playback, what makes you think it is the rewinding which causes quality loss? Tapes lose quality over time whether you play them or not due to breakdown of the binder and dry lubricant. Rewinding is no more damaging than playback if the VCR is functioning correctly. \n\nThere is a phenomenon called [print-through](_URL_0_) which transfers signal from one layer to the next. Professional audio engineers often store reel to reel tapes \"tails out\". That means without rewinding. It doesn't stop print-through, but it does make it happen later rather than earlier, so on playback it will be heard after a track rather than before.\n\nSource: 40 years experience in broadcast VTR/VCR maintenance.",
"VHS tapes are a magnetic tape (that contains the information) wrapped over two spindles. Your VCR scans the tape as it goes from one spindle to the other, and you see the information. Moving the tape back and forth between the spindles and through the read/record head stresses the tape, and damages it over time. Damage on the tape results in lower quality picture and sound.",
"Tapes store the video or audio information on a magnetic \"tape\", and basically what happens is, as it gets used over several years, the magnetic tape loses its magnetism a little bit, so you get \"lowered quality\" in the data."
] |
When a new library is built, where do they get their books? I understand many can be bought brand new from publishers. But, what about the old books, or the vast volumes of dated encyclopedias, dated periodicals, etc... | [
"Librarian here.\n\nA lot of that stuff comes from stores and reserves from other libraries in the system. My library authority has been around since 1890 and has accumulated decades of stuff that due to archiving policies /librarian OCD hoarding we never throw out, For example we have 23 libraries in our group with over 750,000 items. Around a 1/6 of that stock is reserves and then rotated to other libraries so it appears new to the customers of that branch.\n\nEncyclopaedias are really common actually, especially older ones we have around 10 full sets of the most common things like Britannica and Oxford. Any book dealer will most likely have a few sets kicking around if you are short.\n\nIn the UK the British Library has virtually every book and periodical ever published, I assume the Library of Congress is the same in US and we can get copies of stuff from them. \n\nTL:DR a combination of stuff hidden in basements and storage supplemented by specialist periodical providers"
] |
What was the Beat Generation about? Were Beatniks a stereotype or a factual reflection of this philosophy? | [
"Basically, in the 1950s things were very ... basic. Conservative values reigned, the biggest fashion was \"normal\". Some today still think of this as our golden age (unless you're a minority or a woman), but everything was very inside-the-box type thinking. Buy a house with a white picket fence, get a job at the local company, have 2.5 kids, etc.\n\nAt the same time, the US was introduced to Eastern Philosophy and psychedelic drugs. These had existed before, but for various reasons they became more widely available. Beat Generation authors learned about and experienced these things and decided to reject the \"normal\" values. Specifically, they wrote books/poetry about explicitly sexual things, about raw human emotions, about abnormal things like homosexuality, drugs, leaving materialism in favor of a spiritual quest, etc. \n\nThis obviously was not met with praise from the \"normal\" folk, though it was hugely popular with the youth. Eventually a clash happened in the form of a trial over whether Allen Ginsberg's famous poem Howl could be censored/banned because it was obscene. The beat poet won, and really liberalism won, as it was declared that the poem had redeeming social value (which is a pretty interesting thing, that the courts basically gave a stamp of legitimacy to a cultural trend). \n\nAs far as stereotypes vs. real, it is hard to say. It was a huge struggle breaking out of the \"normal\", but it quickly gave way to the hippies and counterculture in the 60s and 70s. People who followed the Beat ideas were mostly authentic, but it would be hard to tease out a \"philosophy\" other than \"we should rebel and form a new philosophy\". Still, as far as being interesting, it definitely is. Ginsberg (Howl) and Jack Kerouac (On the Road) are definitely the two main authors to check out, and both works are relatively short. Also Naked Lunch is fairly famous, and similarly, themed. \n\nOne thing to keep in mind, though, is that along with everything else these guys were purposely rejecting normal narrative style and story structure. So, if you try to read them like a \"normal\" story, you will think it is not good. But if you appreciate what they're trying to do, trying to have an authentic mental/spiritual experience in a very conservative and boring society, it is pretty interesting.",
"I think u/animalprofessor covered most of it, but I can add that you might be able to piece out some philosophical ideas from Kerouac's books Desolation Angels and Dharma Bums. I think that the void and a search for truth underlying a lot of what he wrote, and he was said to capture the generation. Also, the movie The Last Time I Committed Suicide is, at the very least, a pretty cool movie based around the character Dean Moriarty, who Kerouac wrote affectionately about, and at most, a reflection of the desires of that generation.",
"You must read Kerouac's \"On the Road\", Ginsberg's \"Howl\" and Burrough's \"Naked Lunch\". They're canon. \n\nIf they interest you, you can branch out to those author's other works and also to the more \"minor\" Beats and their associates. \n\nI'd specifically recommend John Clellon Holmes' \"Go\", Neal Cassady's \"The First Third\" and Carolyn Cassady's biography of Neal."
] |
If the ozone layer is made up of O3, why are we not producing some of it ourselves and pumping more of them into the atmosphere to fix the problem faster? | [
"> Ozone is a powerful oxidizing agent, far stronger than O2. It is also **unstable at high concentrations**, decaying to ordinary diatomic oxygen. [...] In a sealed chamber, with fan moving the gas, ozone has a **half-life of approximately a day at room temperature**.\n\n_URL_0_\n\nTL;DR: It is very unstable. It will decay fairly quickly; half of the ozone you make today will be gone tomorrow, turned into regular oxygen gas."
] |
What is Gene therapy? | [
"Say you have a recipe for a chocolate cake. Except instead of saying 1 cup of sugar, the recipe says 1 cup of salt. Every time someone makes a cake using that recipe, it's going to taste like crap.\n\nModern medicine is like trying to fix the cake once it's already made. You can add sugar to the top of the cake after the fact, or try to cut out the saltiest parts of the cake. Sometimes, you can try to tell each baker not to add the salt individually. But the best way to fix the problem is the correct the recipe. That's what gene therapy tries to do.\n\nGenes are like recipes for your body. DNA is like the letters in the sentences. Proteins are like the cake. Gene therapy is about cutting out letters and adding new ones so that you get the proper proteins at the end of it.\n\nThe possibilities are endless. There are a ton of diseases that are caused by genetic problems. Some like cystic fibrosis and sickle cell anemia are directly caused by genetic problems. Others like cancer, heart disease, diabetes, etc. are hugely influenced by genes. If you can rewrite disease causing genes, you can eliminate these illnesses at the source.\n\nThe therapy doesn't exist yet. There are lots of experiments, but no one has quite figured it out yet. Once they do, they'll almost certainly cure some major diseases, and win some Nobel Prizes. The most promising idea is to use a virus to help us. Viruses already rewrite genes. Usually when they do, it hurts us. But if you can get a virus to \"join our side\" they can be used to rewrite genes in ways that help people. \n\nGene therapy has a potential downside though. If you can rewrite genes to make people not get disease, what's to stop people from rewriting genes so their kids are 7-foot tall, blonde hair, blue eyed genius supermodels? What happens to people who can't afford the therapy? Genetics does everything possible to create diversity in a society, but gene therapy reduces it. If everyone decides they want to have blonde haired children, what happens when a disease comes along that only kills blonde haired people? There might not be enough non-blonde kids left to continue the human race.\n\nOverall, gene therapy is a remarkable idea that can help billions of people. It has ethical risks, but the benefits would likely far exceed the potential for harm."
] |
Is it possible to be a 'man without a country'? | [
"It is entirely possible to be such a person, it's called statelessness.\n\nAt one point, Einstein was stateless. However, renouncing your citizenship means you have no protection by any state. This is very bad, as we are as a species very largely reliant on our respective corporate states of the world.\n\nI personally identify as a citizen of no country, if you wish to go stateless, I suggest you study the subject further and figure out how to survive without a state.",
"There's was at one time something called a [Nansen Passport](_URL_0_) For stateless people."
] |
How do the grooves on a record/LP actually recreate the sound of a full orchestra? | [
"Think of every single instrument making their vibrations - some loud, some soft, some brash, some smooth, some at one pitch, others at another.\n\nEvery one of those vibrations add up together and bounce against your eardrum in beautiful chaos. The specific way your eardrum vibrates as a result of all that is what your brain is able to process as all those sounds at once!\n\nNow, if you were able to draw the way your eardrum vibrates back and forth like a earthquake seismograph, now you have a line that makes the shape of the whole orchestra! Now just make a groove in that same exact shape, hook it up to a microphone, and now you have those sounds again, just like the instruments were there."
] |
In the English language, how are contractions prioritized when a word can belong to two different contractions? | [
"It's a matter of emphasis. \"We aren't going\" could be simply spoken, or the \"we\" could be emphasized (an emphasis that is lost in simple text). Similarly \"We're not going\" could be used to emphasize the \"not\" part. Beyond that it's preference. The stylistic choices of language are everywhere, and it's one of the main reasons that most sentences of reasonable length have never been written before.",
"Some phrasings are more regional/taught through environment as opposed to what would be most appropriate. Sometimes the different contractions can indicate a mood or assertiveness, but it's not absolute.\n\n\"We're not going\" sounds resolute, has some finality to it. \"We aren't going\" sounds more casual, to me. \"We are not going\" sounds like somebody trying to convince me or guilt trip somebody.\n\nAssuming it's not a conscious decision, I'm gonna go with it just being habit."
] |
Eating things from other planets or moons. | [
"There is a big piece to this question which is not intuitive: chirality. Basically, the food we eat is useful to our bodies because the molecules can be used to build or repair our cells or can be turned into energy. Either way, our cells make use of chemicals called enzymes that are basically molecule sized tools. Enzymes literally fit around the molecules they are designed to attach to, so the shape is very important.\n\nOk, you go to Europa (not proven to have life yet, btw), and find a fish that looks particularly tasty. On inspection, it seems like it is made of similar stuff to life on earth: carbon, hydrogen, oxygen, etc. You eat the fish for a while... And starve to death. Turns out that because the fish evolved on a different planet, it's molecules, while similar to ours, are like mirror images of ours. They don't fit into our enzymes, and so our bodies can't digest them.\n\nChirality appears on earth, too. The chemical that makes spearmint taste minty is a mirror image of the flavor of caraway seeds (found in rye bread and sausages). Interestingly, all life (I think) on earth shares the same chirality, evidence of a common tree of life.",
"Fish have water in them and roughly reflect the ph of the water. This is true no matter how poisonous the water is to us (depth, or non-normal life by volcanic vents). So no, it's unlikely. We are phosphorous based life (not carbon), I've looked but not found any thing suggesting if life there would be the same or not."
] |
The Cuban Missle Crisis and Americas enormous beef with Cuba, what happened there? | [
"The beef wasn't with Cuba, the beef was with the USSR. The Soviets were trying to use their communist ally in The West as a beachhead for terror. (Not the modern definition of terror, the old-fashioned one). By placing ICBMs in Cuba (aimed at the United States) they wanted to cast a cloak of fear over the U.S. Cold War tactics at its finest.",
"US enmity with Cuba started because after the US backed/imposed dictatorship of Batista beginning in 1952, there was an ultimately successful Communist insurrection led by Fidel Castro.\n\nCastro's government ultimately turned out to also be authoritarian/dictatorial and resulted in the seizure of property formerly held by relatively wealthy Cubans (though also some who were not so wealthy; also, left-wing critics hasten to point out that while undeniably politically authoritarian, Castro's regime provided extremely generous social services), many of whom took up a later \"offer\" to freely emigrate from the Island, ultimately winding up in the electorally crucial swing-state of Florida.\n\n*That* revolution and its aftermath was what originally got Cuba on the US shit list; The Cuban Missile crisis was the USSR (which was the great source of US angst ~1950-1989) shipping nuclear weapons to Cuba, which the US really didn't like."
] |
How do you build a Nanorobot..? | [
"Weeeeellllllllllll... the title 'nanorobot' is a bit misleading in this case, they actually genetically engineered some salmonella bacteria (non harmful versions of it at least) to seek out cancer cells. They also filled the bacteria with cancer killing drugs and programmed it to explode on contact with a cancerous cell, providing targeted medication which means they can use more powerful drugs without causing the collateral damage normally associated with eg. chemotherapy (hair loss, nausea etc).\n\nWhile this is very cool and definitely the way forward for medicine, it falls more under the category of Genetic Modification than Nanorobotics. These do have a lot of overlap as a lot of nanorobot production is done using genetically modified cells because.. cells are good at that kind of thing, however there are a load of stigma and negative connotations attached to GM stuff, so most medical development uses Nanorobotics as a descriptor because it makes it more likely to receive positive press coverage and funding. \n\nAnd use, patient confidence is important, which sounds better \"we would like to fill you full of genetically engineered super-bacteria-suicide-bombers blow up your cancer\" or \"we would like to introduce an army of nanorobots to annihilate the cancerous cells\". Actually on second thought those both sound pretty cool to me."
] |
Why doesn't it rain salt water? | [
"When water evaporates, it gets heated to an extent that the water particles move faster and spread apart, which causes them to become \"lighter\" than the air around them, turning into water vapor, a gas. Due to this, they rise up into the atmosphere. Then, they start to cool down, and become liquid again. When they become cool enough that they're heavier than the air, it rains back down.\n\nThis is the basic water cycle.\n\nThe salt which makes it salt water requires a much higher temperature to turn into gas, one which doesn't normally happen during this cycle. Because of this, it does not follow the water, and thus, it doesn't rain salt water.",
"The rise in temperature that is required to evaporate the water is less than that is needed to evaporate salt water, as a result, the water is evaporated and the salt gets left behind. You can see this sometimes if you wear a black hat on a hot sunny day. The sweat on your cap evaporates leaving behind a salty residue (or a white lining) on your cap."
] |
Why can't we use a centrifuge to de-salinate ocean water? | [
"A centrifuge is typically used to separate a heterogeneous mixture of solid and liquid by spinning it. Salt water is a solution, so if it is even possible, I am sure the energy, time and expense are enormous."
] |
Why do most viral videos now have licensing info in the description box? | [
"I'm not sure whether you mean licensing info for the video itself or for 3rd part content in the video, but if it's the former then people angling to create viral videos will want to exert their creative rights over it in case it really does take off, because viral things like Grumpy Cat and Nyan Cat can end up being worth a lot of money. And if it's licensing info for 3rd party content, some content is free to use so long as you attribute it under certain conditions, and one of those conditions is often linking to the license."
] |
What is a MAC Address? | [
"It's a unique device address given to each piece of network connected hardware. It's different from an IP address because it's permanent: every device has one and only one MAC address, but it is given a new IP address every time it connects. \n\nEdit: You can think of the MAC address as a device's permanent name, and the IP address as an instruction for other devices to find it. Your device *is* MAC number X, and it *can be found at* IP address Y.",
"MAC stands for Media Access Control. You can think of it as a unique identifier for an electronic device connecting to a network, like a VIN number for a car on a freeway of other cars.\n\nIf you've got an Iphone, you can see your IPhone's MAC address via Settings > General > About > WiFi Address"
] |
How are adept music players able to just start playing along to anything that someone else plays and have it sound good? | [
"i’m a drummer so i’m not speaking for guitarists/bassists here.\n\nin drums there’s basically three things to improvisation - the time signature, the tempo and confidence (in my experience). \n\nthe time signature is pretty easy to find out - you only need to listen to one bar to figure it out really. \ntime signature is stuff like 4/4, which means there’s 4 quarter notes in a bar basically. kind of easy if you know how to count time signatures.\n\ntempo could be more difficult depending on how much rhythm you have. tempo is literally just how fast or slow you go, at it’s simplest. i’m quite good at keeping time and getting tempo right so i don’t really worry about that but some are worse. if you’re an experienced drummer, you’ll most likely be good at this. \n\nconfidence is key when playing as a whole. only a drummer can tell when a drummer goes wrong usually, you just gotta have the confidence to carry on and ignore your mishap. often it doesn’t matter what drum you hit, just how you hit it and what time you hit it (although obviously some combinations sound better than others!)\n\nanother factor would be experience and knowledge of different beats. if you only know one simple rock rhythm then you’re probably not gonna be very good at improvisation cause you’ll be doing the same thing every time. \n\ni’ve only been drumming for a year in november and i can improvise very well along with guitar/piano so it’s not as difficult as it seems as long as you put practice into learning the instrument and also practice improvising. you’re never gonna be good the first time but you get better.",
"Experience, mostly.\n\nIf you know the key something is played in and it's rythem, you can throw just about anything in and sound good.",
"Experience and ear training. You play enough music and patterns start to emerge and, once you recognize a pattern, you can latch on and let it carry you along. It might take a few minutes to figure out the key, but a lot of music -- especially if you play a specific genre -- is similar; that allows a musician to either duplicate what someone is playing or take off and do a riff on the basic theme."
] |
Why drill instructor in the army never stop screaming at recruit in the army? | [
"> What's the point of screaming at people like that?\n\nIt is intended to rattle the recruits mentally, making them feel like they are incapable and useless. The idea is to break their self-esteem and then the group will be given tasks where the support of the entire unit is necessary to succeed. To drive the point home they will often employ collective punishment so every recruit has an interest in making sure their peers succeed.\n\nAll this has the goal of making the resulting soldiers psychologically dependent upon the military and their comrades. By creating this bond through surviving abuse it puts the soldiers in a better position to be confident in the support of their peers during combat, and for those peers to run into danger in the support of their comrades.\n\nSuch a technique makes great soldiers. It also arguably seriously messes people up when they get out of the military because in essence they have been psychologically abused to foster a bond with the military culture. Ex-military basically have a version of battered woman syndrome and need to relearn individuality and self-confidence outside of the military.",
"Armies thrive on the discipline of individual soldiers. One soldier not doing his/her job can be responsible for getting the entire unit killed in battle.\n\nHaving a drill sargeant yell at you to run faster or do more pushups is a lot less frightening than being shot at, but if you can't handle being yelled at then how can anybody trust you to have their back when you're in real danger?",
"The entire training process (boot camp/basic training) is designed to put recruits through extreme stress. They scream at you, make you do push ups, deprive you of sleep, etc. The idea is that if recruits can not handle the stress of being yelled at all the time than they definitely can't handle being shot at while not having slept and other stresses of combat. Being in a war zone obviously puts lots of stress on your mind and body. The purpose of basic military training is to force recruits to adapt to extreme stress and weed out the ones who can't.",
"A veteran I know said the point of basic training is to break a person so that they can be built up from scratch into a proper soldier/sailor/airman/marine.",
"If you can't handle being yelled at how can you expect to handle being in a fire fight? It's a stress test.",
"Partly it is to develop the instinct of immediate obedience; when you're told to do something, you do it. On the battlefield, if you're hesitating or questioning an order rather than obey it, you are putting other people's lives at risk. \n\nPartly it is to simulate the stress and intensity of the battlefield. If you're becoming nervous and fumbly when someone is shouting at you, how will you handle it when bombs and bullets are going off in your face?\n\nPartly, especially early on, it is intended to disorient the recruits and break their civilian habits. \n\nPartly it is to impart a sort of \"us against them\" mentality, which helps develop the necessary teamwork and camaraderie that the army wants.",
"Bottom line up front: it weeds out recruits who can't handle stress by making the situation as stressful as possible without being in a war.\n\nThe military can't win wars with soldiers unable to handle stress."
] |
if i ground up a piece of pure iron and ate it, would my body abosorb it the same way as iron from food? if not, how do they make iron supplements absorb-able? | [
"You eat shaved iron every time you have breakfast cereal. If you take total cereal, crush it up, add a little milk to make a broth consistancy, and stir it with a strong magnet, you will see actual iron shavings sticking to your magnet.\n\n_URL_0_",
"If you ground it up enough, your body would be able to absorb it. However, the recommended daily intake of iron is only 18mg, so you would need a very small piece of iron or you would run the risk of iron overdose.\n\nHowever, iron supplments are usually provided as part of a compound, such as iron (II) fumarate, iron sulphite, or iron gylcinate, which are absorbed more readily by the body.",
"A fun fact along side other peoples post: One of the benefits to cooking with a cast-iron skillet is that it increases the iron level in the food because little bits of the iron stick into the food itself."
] |
Whats is the actual cause of the common itch. and why is scratching it the cure? | [
"1: dead skin\n\n2: your body's reaction to get rid of it.\n\nBonus: a lot of dust in your house is said dead skin."
] |
When popcorn is popping, what is actually happening to the kernel inside? | [
"As the kernel is heated, the moisture and oils are being heated inside. Since the outer shell of popping corn is strong and mostly impenetrable, there is no place for the heat and pressure to go and the insides are superheated. The starches inside, which are normally hard, begin to soften in a process called gelatinization. Interior pressure continues to rise until the kernel's shell ruptures. Steam rapidly expands causing the innards to expand in a foamy substance, which afterwards quickly cools into a crispy puff."
] |
What happens to your brain when you space out? | [
"There are two kinds of spacing out. There is background processing - thinking about stuff that isn't apparent to you consciously, and basically resting your mind. \n\nFor most of evolutionary history, energy was the limiting factor for most species. Sleeping is not only helpful for repairing your body, but also for reducing your calorie burden. Spacing out is a kind of low energy state that is more alert than sleeping but less energy consuming than active thinking."
] |
What is the point of a Kroger's Shopper card? | [
"The general idea is that by offering a discount card, you will shop more frequently at that specific chain than others (although in reality, this isn't often the case). They may also collect your email to send you regular marketing ads, in hopes of bringing you in.\n\nIf the extra profit generated from you buying items at that store vs another store exceeds the discounts given on that trip, then the store benefits.",
"Probably the biggest use is market research on what your buying habits are... when do most people go shopping? (so we can increase the cost of milk on that day). What do you buy most often (so we can increase the cost of that item).\n\nI'm cynical if you can't tell and I refuse to shop at Kroger for various reasons (this being prime among them). I think of it as way to screw people and charge them more for not having the card. (yes it's free but see paragraph one)"
] |
What is a floating neutral and why is it damaging to appliances? | [
"Coming into your house you have two phases which are both 120VAC *relative to neutral* but are of inverse phase so they're 240VAC relative to each other.\n\nA floating neutral is when your neutral connection opens for some reason, a wire might break. When this happens, it means that the electricity can't flow in its normal path.\n\nIf an outlet was powered by a straight pull from the breaker box and has hot come from the breaker, go to the outlet, then neutral runs straight back, then losing neutral means that power stops flowing and nothing exciting happens\n\nIf your outlet is wired so the top and bottom plugs are different circuits then one is going to be Phase A and the other Phase B. This means that when the shared neutral breaks, any devices plugged in will go from seeing 120VAC to seeing 240VAC which will destroy many devices quickly."
] |
Why haven't our bodies changed to make childbirth less painful? | [
"So the only way that the process of childbirth would change is through evolution of some kind. The only way evolution happens is if the genetically superior reproduce and those who aren’t die. Theoretically if there was a woman who could go through childbirth totally painlessly and she passed that trait on to her child, the child could pass the trait on and on until it made up the mass populous. This would take millions of years and to guarantee that all women experienced it, all who felt pain during childbirth would have to not reproduce. \n\n\nThink about it like this. Apples were high on the tree. All the long necked giraffes reached the apples, lived and eventually reproduced. All the shortnecked giraffes died and that’s why we only today see long necked giraffes.",
"Doing so would require humans to get either smaller heads or wider pelvises. Smaller heads would mean less room for a brain, which is of course a huge detriment. The other option sounds good in theory, but makes bipedal walking much harder. Throw in the fact that modern medicine has pretty much removed any evolutionary pressure, because its not like pregnancy complication resulting in death are the norm. That said we did evolve a tiny bit to make childbirth easier. Instead of giving birth to a more grown and able bodied baby, we give birth to a useless significantly less developed baby, because they are smaller.",
"> why is delivering children such a painful and uncomfortable process?\n\nHumans have the niche of being extremely intelligent bipedal hairless mammals. The bipedal and hairless part means we can walk and run very efficiently, while maintaining our body temperature via sweating. It is also very important when coupled with our intelligence in that it leaves our arms free to hold tools and to throw them accurately using our very capable vision processing areas of our large brains.\n\nBut the problem we have is our brains need to be big in order for us to be intelligent, and our hips need to be relatively narrow for our bipedal gait. But our brains go inside our skulls which must pass through our hips at birth! So our brains being big works directly against our hips being narrow.\n\nThis has pushed human babies to be born relatively prematurely which is why human infants are so useless at birth. This is OK because with our intelligence we can take care of them, and by being born early their heads are smaller and the skull not yet fused so it can pass through the hips. However it is all still pushed to the limit so the birth can be relatively painful and dangerous.\n\nEvolution doesn't really care about pain though and this state is the most effective given that we cannot have an intelligent redesign of how things work."
] |
American TV shows compared to The rest of the world. | [
"The amount of American hate / bashing on Reddit is amazing.",
"Don't act like we Americans don't notice this shit, too.",
"They make it into a drama type show to get more people interested. Most Americans wouldn't watch it if it was like the British version because it's not \"interesting\" enough for them.",
"Oh sorry, I thought this was r/ELI5, not /r/thinlyveiledwhiningmasqueradingasaquestion.",
"This issue here is money. \n\nIn America, there is a big difference between Network television and Cable television:\n\n*Network television is broadcast over the airwaves, and can be picked up for free by any television with an antenna. Therefore, the only way that the large television networks (ABC, NBC, FOX, CBS) make money is through commercials. \n \n*Cable television is only available by subscription and people have to pay to view the channel's content.\n\nSince Networks are entirely dependent on commercials for revenue and they can charge more for commercials based on their ratings, Networks are obsessed with attracting the largest possible audience. There is a certain amount of moron viewers who want (need?) to be told what to think/feel. It's not necessarily that they are not able to do it on their own, but it is more enjoyable for them if they do not have to think or analyze what is happening. Even if this is 1% of the audience, the network cannot afford to leave them behind. Therefore, Network show strive to be as attractive and easily digested as possible to appeal to the least common denominator. \n\n\nThere are plenty of American tv shows that do not use cheezy dramatic cues/devices (Breaking Bad, the Sopranos, The Walking Dead, etc.) These shows are wildly popular in America, but are almost always on premium cable channels. Much like cable television in America, the BBC receives some (most?) of its funding independent from commercials. Since these content providers do not have to play down to the idiots of the population and are able to retain more artistic integrity as their revenue stream is more stable.\n\ntl;dr - Networks in America have to make content as easy to understand as possible to attract as many viewers as possible, including morons.",
"Most American TV shows aren't like that though. Just silly reality shows are. I mean really, America has produced by far the most good TV of any country.",
"American living in Switzerland here and I noticed many of the German/Swiss/Austrian/French/Italian channels have American TV Shows, trashy reality shows aside I think most Europeans are fans of popular TV shows. Most of what I watch here is dubbed with the respective countries language."
] |
How do people add colour so accurately to black and white photos? | [
"It's basically painting a transparent picture on top of the black-and-white, and the B/W image provides much of the shading. \n\nIn the days before photoshop, you had actual transparent inks with limited tints to choose from, and that's why old hand-colorized photos often look more cartoony.\n\nNow, you can pick from a vast range of colors until it more or less matches what you would expect: a white person with fair hair will probably have skin in X color range, unpainted wood furniture is going to be a shade of brown, jeans are almost certainly blue, a military uniform from that era is going to be this particular color, etc. \n\nPlus if you have experience with B/W photography you might have a sense for how some colors will translate to film; they often have a particular range of grey due to the characteristics of a given film.\n\nSo accurate colorizing mostly comes down to digital painting skill and having a sense for how things would look.",
"What makes you think they do an accurate job?",
"I'd also like to know why every *single* person has blue eyes when they DO colorize it.",
"They just sort of guess what the color would have been and then add that in. In some cases they've seen the subject of the photo in real life or have historical evidence, so they know exactly which colors to make it.",
"Most black and white photography is somewhat gray scaled. With enough experience, once can predict the colors based on the pattern and gray scale, relative to its surroundings and application of every day life. You know certain flowers bloom a certain color,so that could be a starting point. And there are a few different ways it happens, but that was the way my grandfather explained how they did it to all his old photographs and movies.",
"It depends on the type of photograph and who's asking them to do it (like if a family member asks, they can provide worlds of info.) If you get a random photo of, lets say, a woman in the 1940s and shes modestly dressed in a hat and a dress, chances are the dress would be a shade of red/green/blue/yellow if there's a print on the dress and its flowers, well, green or yellow would be the way to go. Shoes, 90% of the time will be black, if its a light colored shoe, its going to be a tan or a white. lets also say shes holding a purse, generally a brownish or black if its dark grey or a white/tan if its light grey. Now depending on the photograph you will automatically gain an idea of what colors *would* be there, not really the colors that *are* there.\n\nIf you want a better explanation, go to r/colorizedhistory. The folks there, especially u/zuzahin do insane amounts of research into the time periods of the photographs they color. Just ask, they will be happy to tell you why they chose a particular color for a particular item. For instance, I did one of Audie Murphy a while back - _URL_0_ - Every medal is the actual color of the ones he earned, the uniform is the actual color of the uniforms of the day, the buttons as well. Looking at older photographs of him, eyecolor and general skintone can be found. (folks skin tends to get a muddier hue as they get older) so I compensated for his youth. However, knowing his story, and his torment, I colorized it to represent more of what he was going through internally. This is where artistic licence, for me, takes over... unless someone is paying you to do a colorization.\n\nEdited for der grammuh"
] |
How do service animals help autistic children? | [
"Multiple ways, and by the way it's not just autistic *children* who can benefit from service animals.\n\nAmong other things:\n\n* service animals can detect the early signs of a meltdown or shutdown, which are things often (but not exclusively) triggered by sensory overstimulation, and can provide a prompt to leave the situation causing that overstim\n* they can provide active stimulation to aid with grounding\n* they can help reinforce ritual, which is frequently important for autistic people",
"One of the major issues that autistic people have is that they cannot process new information quickly, have problems with crowds of people, and have difficulty controlling their panic response in new situations. So having something like a pet that can help to keep them calm and focus their attention slightly when in such a situation will help them have the time to process without panicking."
] |
Why do books downloaded from the library need to be "returned" after a given amount of time? | [
"> This makes no sense because downloads are not limited like physical copies of books are.\n\nDownloads are limited in the sense that the library has to pay for every copy of a book that they own, including digital copies. So they pay the publisher $X for permission to lend some fixed number of digital copies. And the reader software is set up to that the borrower isn't able to retain possess of that copy forever.\n\nIf that weren't the case, then book sales would drop essentially to nothing, since everyone could just get a free copy of any book whenever they wanted for as long as they wanted.",
"Publishers want them to be limited though. Otherwise, people could just borrow as many books as they wanted and it'd be no different than buying them. They work out licenses with library on how many digital copies can be \"loaned\" out at a time. I'm not sure if it's the library or the publisher that sets limits on how long they can be borrowed though."
] |
How does Stephen Hawking's speech computer work? | [
"He has a small sensor in his mouth and uses his cheek muscle to type with it. His computer also has the ability to predict and correct words for him."
] |
If a self-driving car detects multiple courses of action (all of which will likely result in human injury) how will it determine which course to take? | [
"It will do whatever it is programed to do in that situation. Self driving cars are not true conscious A.I - they are just really, really complex \"if...then\" programs. If it gets into a situation where an accident is unavoidable, it will do what its programing tells it to do in that situation.\n\nAs far as liability, we don't know yet. It's possible that the programer would be liable for the accident but we'll need a court case to set precedent before we really know.",
"I think that currently, self-driving cars are not equipped to make moral or ethical decisions. They aren't concerned with hurting humans or not, because they don't know what humans are or that they even exist.\n\nIt simply sees obstacles, and does it's best to avoid running into them. Doesn't matter what that obstacle is. If there are multiple courses of action, it will pick the one least likely to cause it to hit something.",
"AI systems typically assign each outcome a score based on a variety of criteria, and pick the best score. \n\nFor example, one alternative my have a 90% chance of avoiding an accident (+10 points) but would injure 4 people (-4 points) if there was an accident. That outcome would have a score of 6 points, and be compared with other outcomes.\n\n > And ... what liability issues could arise from whatever decision the algorithm makes?\n\nThat is a legal matter that has yet to be resolved. It will likely require legislation that grants some degree of immunity to the people who design the software.",
"As said nelsewhere, it depends on what it is programmed to do. \n\nIt would make sense to do the less invasive action possible, which could in fact result in higher human injury in a few cases. \n\nFor example if it finds itself driving over petrol that then catches fire and thus detects a series of malfunctions, it would most likely stop, and this could well mean the occupants have a higher risk of injury and death than if the car accelerates out of there to a safer place. \nThis way the person liable for the burns is whomever started the fire, not the car. \n\nIt's a matter of ownership of the actions. If you decide to take an action that results in a loss of life you are liable, however if you decide to NOT take an action that results in the loss of life then whomever created the dangerous situation is to blame. \n\nThis is exactly why in the [\"trolley dilemma\" thought experiment](_URL_0_) on both examples I answer that I would not take action.",
"These thought experiments are so trite and contrived as to be useless except as an academic exercise. Real self-driving cars have driven millions of miles on roads and thus far have only been involved in collisions wherein they have been hit from behind by human-operated vehicles. In only one case can the self-driving car be blamed for the collision, and even that case is debatable, and was at a very low speed.\n\nThe question presumes a driver who is almost by definition behaving irresponsibly prior to the situation described. Human drivers do this routinely, but there's no good reason for computer drivers to do so. If the driver can't see around an obstacle close to the vehicle's path, it should obviously not go so fast that it would be impossible to stop before colliding with a pedestrian (or whatever) should one appear. Human drivers are generally incapable of exercising adequate caution, paying attention consistently, and judging their own capabilities accurately. For computers, these tasks are trivial.\n\nIn practice, in almost all situations, the answer to the question of \"what will the computer driver do?\" is simple: stop the car as quickly as possible without losing control. And the computer will also be much better at that task than its human counterparts, because it will more alert (detecting the problem sooner), quicker to act (no moving a foot from one pedal to another), and better able to control the vehicle's brakes near the limit (no need for inefficient anti-lock brakes if you know how hard you can brake without causing a wheel to slip.\n\nFurthermore, it's likely that when a self-driving car does get into a situation where a collision seems unavoidable, it will be because of major system failure (the computer doesn't have full control of the vehicle). And whether or not that's the case, it's probably going to be all about minimizing injuries, rather than deciding who lives and who dies. Reducing speed is the most important thing for that.",
"In a perfect world, the decision would NOT be a lone decision. with in a group of self driving vehicles, all vehicles would come to a single decision based on the others in that immediate group. This would be similar to the aircraft collision avoidance systems. As 2 aircraft are on a collision course, they communicate and make a mutually beneficial decision......One aircraft will descend and the other will ascend.\n\nThere have been instances where the pilot ignored the computed path an it didn't end well.\n\nwhat it comes down to is less damage less injury.....the key in such a situation would be communications and more automation.",
"It will be interesting to see what happens, because a car could actually compute the safest way to navigate while being involved in a crash.\n\nDoes it turn slightly so it hits the oncoming vehicle at a different angle to lessen the impact and reduce rollover/additional vehicle involvement?\n\nDoes it turn to spin the car harder to prevent it from drifting into another oncoming vehicle? etc\n\nAll of this stuff might go a long way to actually preventing serious injury in accidents that would normally be caused by a panicked driver."
] |
why does spicy food make me sweat? | [
"\"The answer hinges on the fact that spicy foods excite the receptors in the skin that normally respond to heat. Those receptors are pain fibers, technically known as polymodal nociceptors. They respond to temperature extremes and to intense mechanical stimulation, such as pinching and cutting; they also respond to certain chemical influences. The central nervous system can be confused or fooled when these pain fibers are stimulated by a chemical, like that in chile peppers, which triggers an ambiguous neural response.\"\n\nSource: _URL_0_"
] |
If there are no size regulations regarding goalies in the NHL, why doesn't a team just throw some really obese person out there to block the whole net? | [
"An NHL goal is 6 feet wide by 4 feet wide. I doubt there's many people actually large enough to block that entire area. And if there is someone that big, I doubt they'd be able to stand up and skate their way out to the net.",
"Also take into consideration that the NHL does have restrictions on pad size. Lets say you put a big sumo wrestler in goal, he would have a lot of exposed area. Would you want to repeatedly take 100 MPH slap shots to unprotected part of your body?",
"Assuming you did find someone large enough to block the entire opening (you won't), they'd still have to stand. They are not allowed to lay down in front of the net for the entire game.",
"There was an [article](_URL_0_) about it and there does not appear to be any current rules against it.\n\nHowever there are a number of problems with the main one being that while the size of the man isn't regulated the size of the pads is. On someone so massive, 800+ pounds, there would be a LOT of area exposed to 100MPH pucks and slashes from angry players. Even in the experiment in the article the goalie didn't cover the entire net and had to move around and with all that weight even basic movement was very tiring.\n\nThe second reason is the NHL would consider it a dick move and create some rules before it became too game breaking.\n\nEdit: Third reason is because you have to have a physical to be allowed on the ice. No doctor would certify a 1,000 pound person to play hockey.",
"Nobody is big enough to block the whole goal, and goalies are actually pretty athletic. The bulk you see is as much pads as actual person. They need to be quick and fearless (possibly a little bit crazy too). \n\nNext time you watch an NHL game, watch how much the goalie moves. He's constantly moving, evaluating and adjusting to the puck. He's also got to be quick enough to catch the puck, or smack it away or dive on it."
] |
If animals aren't aware that they are going to die, why would they try so hard to survive? | [
"Because they are genetically programmed to. It's evolution. Individuals that do not try to survive are not able to live long enough to reproduce - or in some species' cases, to care for their young either (imagine a mother dying and leaving her babies helpless).\n\nTrying to survive doesn't mean you need any special awareness of what death means though. All you need is to be programmed to run at the sight of a particular predator. Your computer is programmed to run millions of things, even your programs literally try to survive without crashing, but it doesn't mean your computer needs to be self-aware to perform those tasks. Self-awareness is not required for a survival instinct.\n\nAt its most basic level, it's programming that says \"Bad thing detected. Flee from or kill bad thing.\"\n\nIt's wrong to even say they have motivation (for most animals), it's simply just what they do. It's like asking why your car tries to survive. It's a false question. Motivation isn't a factor.\n\nFor your more intelligent animals, survival is a motivator because survival means avoiding pain and suffering. They aren't really thinking \"I want to survive\" so much as they are thinking \"I want to avoid horrible pain\".",
"Does a falling ball \"know\" it's trying to return to Earth? Or does it just do what it must?\n\nAnimals behave out of instinct. When hungry, they are driven to eat. At a certain time of year, they are driven to mate. When startled, they automatically flee. They don't know the effects of these actions, but that isn't necessary.",
"You need to remember that animals are VERY different to humans. \nA lot of the stuff we take for granted is totally alien to them. Measurements for one thing. A cow doesn't care if it's Sunday. \nThey might have a notion of 'Its now warm and light so I can find food. < And later > Now there is less light and cold, So I'll sleep', but what does 3pm mean to them? Nothing. \n\nEqually, An animal won't 'Ask for' or 'Demand' stuff, nor will it issue orders or instructions to its peers. It probably dosen't even see them as peers. It wouldn't have 'Questions' 'Laws' 'Political correctness' 'Politeness' 'Etiquette' or anything like that. \n\nLets reduce it to a basic scenario. When we point our finger human beings follow the direction of the finger whilst cats look at the end of the finger.\n\nThere is a quote from Wittgenstein: \n'If a lion could talk, we could not understand him' \n\nIts frame of reference would be so far removed from our own, That would not be able to understand what they are talking about, and they wouldn't not understand what we are talking about. \n\nSo they may not understand death - Or they may - We don't know what their frame of reference is.",
"What makes you think that animals dont know that they will die? \nOf course they might not conciously think about it like humans, but for example, alot of animals know when they are nearing death. \nAlso, survival is a broader term for many aspects of living. Eating when you are hungry, running / fighting when you are in danger, tending wounds when something hurts. These are all part of survival, but they do not require you to actively think about not dying. Being hungry sucks, so you go eat.",
"survival is built into our DNA through natural selection, a principle first coined by Darwin (and Wallace). Basically, populations could grow exponetially, however there are limited resources and there are variations that arise within all populations of organisms (through mutations, and interaction with the environment over time). Those with the favorable variations (ex: deer's reflex to take flight when startled by a noise or visual) are more likely to survive, and thus spread their favorable trait to the next generation (through sexy stuff)."
] |
How can a computer come up with a "random" number? | [
"Generally yes, anything generated by an algorithm can be reproduced if you know the \"initial\" settings. Numbers generated this way are referred to as \"psuedorandom\". \n\nThere do, however, exist various dedicated hardware solutions that allow computers to pick truly random numbers. They work by basically installing in the computer some sort of sensor that can detect random properties of nature. \n\nAn example might be some sort of detector that picks up low levels of radiation. While we can make statistical predictions of radioactive decay over time, the actual decay of individual particles is truly random, and cannot be predicted with perfect accuracy. A sensor designed to measure those tiny random variations and feed them to a computer could generate truly random numbers."
] |
Why are scars near impossible to get rid of? | [
"Scar tissue is different to normal skin. It contains more collagen than regular tissue, and doesn't structure the same as regular skin, which is why it looks so different. It's also less flexible.\n\nThe benefits to having scar tissue is the body can recover from wounds exceptionally quickly - many animals can't create scar tissue, and so wounds can remain open longer and are more susceptible to infection and other problems. Conversely, other animals can regenerate entire limbs whereas we can't.\n\nInterestingly, the collagen in your scar tissue is constantly replaced. If your body stops producing collagen (due to certain illnesses), your scars' wounds can actually reopen.\n\nThe scar is difficult to get rid of because the tissue has been created in a less structured/ordered form than your regular skin (because it was deployed quickly to help heal the wound), but some medical procedures exist to reduce that effect.",
"Scars are a normal and natural part of the healing process. When the body heals, collagen protein which is found in normal and healthy tissue in a randomish (basketweave) pattern, forms in a more organized way. This allows for healing but because it is different than the normal skin - it stands out. Over time some scars will almost disappear and sometimes corrective cosmetic surgery can be done to further minimize their appearance. A general rule of thumb is: if the full thickness of skin (all the different layers) have been disrupted - there will be a scar. If the wound is managed well, it will scar less.",
"Scars are part of your normal skin, and while they are remodeled over time, this is a very slow process. The bigger the scar, the longer it takes to be remodeled. That's why major scars will usually never heal back to normal."
] |
Why don't developed countries make their own clothing without child labour? | [
"Because it's cheaper to have it made in other countries.",
"Its not the technology; remember, much of that technology was invented here in the US. Plain and simple, a shirt (and just about anything) from Mexico, Thailand, or Bangladesh is $2-3 cheaper wholesale than American made (in general. Source: former screen printing business owner). The general public says they don't care, but we vote with our wallets. Nobody wants to pay more. \n\nIf you don't like child labor to be involved in your purchases, be an active consumer and buy stuff made in the US or Canada. That's the only way to change it."
] |
Two spaceships are travelling towards each other at speed of light.. | [
"First thing's first, neither ship can travel at the speed of light. As long as they have mass, it just can't happen. This isn't some silly nitpicky thing, it's fundamental to the theories of relativity, and it really honestly doesn't make sense to talk about massive things travelling at the speed of light.\n\nBut in any case, your question works just as well if they're both going at, say, 0.9c. Now, the reason that the speeds don't add up is that whoever told you they should was wrong. Speeds don't actually work like that. Weird, huh?\n\nWhat's actually the case is speeds really add in a slightly different way, given [here](_URL_0_). As long as the speeds are small compared to the speed of light, they add more or less in the inuitive way with one plus the other. But as they increase towards c, the rest of the mathematics is essential to the description and velocities turn out not to add linearly after all.\n\nEdit: Just to be clear, this all depends on what frame of reference you ask the question from. Are you on a spaceship, or directly between the two ships, or standing to the side, or what? If you're on a spaceship and they're both going at 0.9c relative to the stationary frame watching them, you'll see the other one approaching at about 0.994c. But if you're standing 'stationary' in between them, you can calculate their relative velocity to be 1.8c, even though neither ship will measure the other to be travelling that fast.",
"> ...but how the hell do the speeds not add up??\n\nThey do add up, but in a way you might not expect. The reason they add up differently than you might expect is that you are using a model of 3D space with an independent time dimension (Newtonian model); in fact, we don't live in a 3D world of space plus 1D time, we live in a 4D world of space-time (Einsteinian model). The chief difference is that the three dimensions of space are not independent from time, all 4 interact.\n\nThis seems very mind-bending at first, but here is the key to understanding it. Imagine you are a 2D person living in a wall surface. That is your world, and you cannot conceive of a 3rd dimension. I might say, hey 2D person, check out my ball! You'd say, where? I'd say, ah, you can't see outside your wall, let me put my ball on your surface so you can see it. Well, my ball would only touch your wall at one point and you'd say, ah, nice point. No, no, I say, this isn't a point, it's a ball. here, let me show you. So I start pushing my ball through the wall. You see the point grow into a circle—well, not actually a circle, it's only a circle from *my* perspective looking at the wall. From your perspective, you'd say, ha, nice semicircle. (You would see a curved line segment and have to walk completely around it, then you would say, ah, nice circle.)\n\nOk, so now we're comfortable with 2D you. So now what I do is I set up a light in my room, and I'm going to take out a meter stick and hold it in front of the wall so a shadow is cast. You see the shadow and walk around it and say, ah ha, that's a meter long. Great! Now let's look at some rotations.\n\nLet's call your wall the x-y plane, just so we can establish some directions. It turns out that I'm holding the meter stick along the x-axis. So now I rotate the meter stick so that it's at 45 degrees in x-y. You say, ok, it rotated, still a meter long.\n\nWait. Why do you think it's a meter long? If you think about it, in the x direction before, it was a meter. Now, if you look at the length of the shadow along the x-axis, it's 0.85 meters, and it's 0.85 meters along the y-axis. This adds up to ~1.7 meters. How can it be that you and I only see it as being a meter long? Well, this is simple stuff, right? It's because we don't just add x and y, you have to use the Pythagorean theorem to say x^2 + y^2 = L^2 ... now we can see that L is 1. It would be silly just to add the x and y components like that...what were we thinking!\n\nWhy is it so silly, though? Well, because we know that x and y *interact*. They are not independent dimensions. When something is rotated so that it extends into both dimensions, we know that the total length of that thing is not simply calculated by summing the thing's projection in both dimensions. *How* do we know this, though? You and I might both accept that x and y interact, fine, but they could interact in all sorts of ways...how do we know they interact in *this particular* way?\n\nIf you think about it, you'll be able to convince yourself that this makes sense because we know something is preserved: the overall length of the meter stick. No matter how it's rotated, it must always be 1 meter long. Knowing that, we have identified an invariant, and since we know the length of the thing never varies, we figure out how it extends in two dimensions. Great!\n\nOk, now I rotate the stick in z. Wait, you say, the shadow just got *shorter* for you. To you, this seems very strange indeed. We just went through a whole bunch of reasoning saying that the length of the stick is invariant, and here now the shadow changes overall length. This can't be! Well, it turns out it's ok, because I explain to you that even though you can't see it (or even conceive of it), there is a third spatial dimension and I've rotated the stick into that dimension. If you're clever, you can convince yourself that the actual meter stick is still 1 meter long even though its shadow is shorter. You can measure its extension in x and y directly, and then you can calculate its extension in z even though you can't see that dimension directly. You can do all this because the meter stick is still 1 meter long, and you've identified that as the invariant. Furthermore, you know that z is related to x and y the same way that x and y are related to each other, so you don't simply just add them all up to make 1, you have to use the Pythagorean theorem.\n\nHere is what you need to know about relativity. Time is a dimension that relates to 3D space, just like z relates to x-y for the 2D man in the wall. If you do experiments, you can observe that \"speed\" actually rotates a thing into this unseen time dimension. To us and our Newtonian way of looking at things, it *appears* as though the thing just gets shorter in the direction of motion, just like the shadow for the 2D man gets shorter. Where did that extra length go? It's still there, it's just rotated into a dimension we can't observe directly.\n\nNow think about how the 2D man in the wall measures stuff. He carries around a 2D meter stick. Before, he knew the shadow of our meter stick was 1 meter long because he compared it to his 2D stick. But when we rotated our meter stick in the z, it got shorter according to his meter stick. His meter stick can only tell him about lengths that extend in x and y, it can't tell him about the \"real\" length in 3D. Likewise, we can't go around measuring things in a way that only take account of 3 out of 4 interacting dimensions. (If time was totally independent, this would work just fine...but it's not.)\n\nSo instead, we must measure things in all 4 dimensions. Unfortunately, 2D man has no idea how to know if he's dealing with a 3D meter stick, or something of some other length that just *looks* like a thing that's 1 meter long. In order to figure this out, he has to get control of a 3D meter stick and rotate it in all different ways in all 3 dimensions, and if the longest he can ever make it is 1 meter, then he knows that's how long it is in 3D and he has his meter stick. He has found something with a 3D length of 1 meter, and he knows that 3D length is invariant.\n\nWe need the same thing in space-time. Fortunately, we have it in light. By experiment, we know that light always travels at c relative to everything. So, we can define our meter stick in terms of how long it takes light to get from one point to another. As long as we measure distances this way, everyone can measure the 3D space between those two points, and then, just like the 2D man calculating z, different observers that disagree on the 3D distance between those two points can know that, actually, in 4D, they are the same distance apart. And, they can calculate the extension into that time dimension just like 2D man does with z.",
"> Two spaceships are travelling towards each other at speed of light..\n\n**AHHHH!**",
"I think a lot of the already posted answers have misunderstood one important point in your question:\n > And an outside observer still observer the relative speed in between them to be c.\n\nThat part is not necessarily true, but you have to specify that both spaceships are traveling in opposite directions at speeds near c *realtive to the outside observer*. If I saw a spaceship approching me from the right at .9c, and another approching me from the left at .9c, then I would observe the space between them to dimnish by 1.8c. The crucial point is that neither of the *spaceships themselves* would observe the other to move at above c -- while you can indeed never observe something to have a speed greater than c relative to yourself, you can still observe things moving at up to (not inclusive) 2c relative to each other. \n\nThis would also be true if two spaceships both travelled from earth in opposite directions: if both acheived speeds above .5c, then us here on earth would observe the distance between the spaceships to increase at a rate corresponding to more than c. Each spaceship, however, would always observe the other spaceship as having a speed less than c, relative to themselves. A consequence of this would be that earth would observe the distance between the spaceships as being greater then what the spaceships would observe it to be, as from earth it would appear the distance between the ships has increased at above c, but from each ship it will always appear to increase slower.\n\nShit, this got kind of long. **tl;dr:** an *outside observer* could observe the relative speed between two ships to be greater than c (but less than 2c), but the *ships themselves* would observe their relative speed to be below c.",
"Speed = Distance / Time\n\nSo if we set a maximum value for speed (the speed of light) then distance and time must get distorted to make up for it. That's why we see [length contraction](_URL_2_) and [time dilation](_URL_2_).\n\nFrom your point of view the spaceships appear shorter and time on board would be moving slowly (or frozen if they were moving at the speed of light)"
] |
Why can we eat sushi raw but not other meats? | [
"The short answer is: If it's clean, you can.\n\nWeather we can eat a food raw or not depends on if it carries things that might make us sick, or might have picked up something that would make us sick. \n\nIn particular, with Sushi, fish is processed in methods that separate the \"dirty\" bits quickly, and completely. (gutting a fish) That leave you with clean, safe, slabs of fish to work with. Also, things that make fish sick, don't necessarily make people sick. Importantly, care is taken so the surfaces of the deceased fish are kept clean.\n\nSomething such as beef, isn't processed as cleanly, or quickly. And cleaning and speerating the cuts isn't as clean. They also can be made sick by the same things that make us sick. \n\nIf you treat \"meat\" right, raw meat is just fine for you. Steak Tartare, and Carpaccio are both rare preparations of beef. If you take the same sort of care that you do with fish, you \"can\" eat meat raw. \n\nRare steak, is essentially raw in the middle. The advantage there is by quickly cooking the outside, you kill the bugs that might be on the meats surface. \n\nThere are also other ways of making meat \"clean\" that don't involve cooking. Pickling, salting, smoking, all could still be \"raw\" food, depending on how you define it.",
"[Carpaccio](_URL_1_) and [tartare](_URL_0_) are very common dishes of raw meats.",
"You can. In Germany and France it is very common to eat raw beef and pork. It is actually pretty yummy. You just have to be careful.\n\nIn japan it is popular for people to eat all kinds of raw meat. Chicken, pork, beef... whatever.\n\nThe USA is very strict on not eating raw meat but that is also because it pays so little attention to how animals are actually treated and raised.\n\nNow I want some raw ground beef and pork with some cucumber and onion...",
"FYI sushi doesn't mean raw fish. That would be *sashimi*. Sushi is basically rice rolled in seaweed. Other stuff, mainly vegetables and *fish*, may be added.",
"In Japan, I have eaten raw: fish, beef, lamb and horse. The chefs know how to minimize sepsis so that it's not dangerous to eat.."
] |
Why is it when oil prices go up gas prices immediately go up but when oil prices come down the price of gas never comes down as fast as when the price of oil increases? | [
"On TV, when the price of gas goes up, they say they have no choice but to sell it higher in gas stations too.\n\nBut when the price goes down, they say that they had already bought a lot of gas when it was higher so they cannot lower the prices immediately or they'd lose money on it.\n\nThere is probably a good explanation for it but my guess is that it's another of these \"Heads I win, Tails, you lose\" situation ;)",
"This kind of pricing is called \"sticky downward\" and often happens in cases of limited competition. When the price of production goes up, the price to the consumer goes up. When the price of production goes down, the price to the consumer is held constant and the reduced demand is managed by not producing as much. The excess value per unit is kept as profit, as long as the producer can do so.\n\nBut because there is SOME competition, there will be a gradual reduction in prices, as some producers and resellers will reduce their prices over time to try to gain more of a market share.\n\nTake gas as an example. Let's say due to some event the price of oil spikes up, and so the price of gas increases by a dollar. For the most part, people will still need to buy SOME gas. I'm not biking ten miles each way to and from work every day, though some people will choose to walk or bike, so I will still need to buy enough gas for my commute. It may make me decide against taking a road trip I was going to take, though, reducing total demand (and thereby reducing the sellers' revenue).\n\nAs oil goes down, the cost to produce gas goes down, but the gas stations will still like to sell at the higher price as much as they can. I still need to buy enough gas to commute, so I pretty much have to pay their price. But say the Sheetz I usually go to is selling for $4.259/gal, and the Exxon just a couple blocks up the road which WAS at $4.259 drops their price to $4.209 to try to get my business. In my own case this would work. I'll drive a couple blocks to save $.05/gal. So the Sheetz may respond by dropping their price to $4.199, and the Exxon may then drop to $4.179, etc. It will eventually reach equilibrium, it just takes more time.",
"There are a lot of gov't regulations that state what the gas stations (and their suppliers) can and can't do with prices. They are only really allowed so much flexibility.\n\nImagine the oil as coke (soda, not the drug). Now let's say Coca-Cola decides they want to charge forty dollars for a box of the concentrated Coca-Cola flavoring used in a fountain. (I don't know the actual measures here, so don't take these as legitimate numbers, more just hypothetical) Now, that box can make 100 22 oz cups, and a fast food place buys two of those boxes. They have 4400 oz of soda they just spent $80 on. Not counting the cost of water and employees, they need to sell each oz at $0.02 to make back the cost ($0.44 for a 22 oz cup, probably being sold at $0.55). Now imagine what happens when Coca-Cola decides to charge more for that box, the cost per cup has to rise. The store still buys the same amount of product, but because they are charging a higher price (let's say, $0.88, sold at $1.10 after markup) they don't sell it as quickly. Well, they eventually sell off the soda they bought at a higher price. During that time, Coca-Cola has lowered the cost of the box back to the original price. That leads to, after a little delay, the cost lowering and the same profit being made.\n\nThis happens in a bunch of things really, ever notice when a grocery store starts charging more for tomatoes or bread? Then you notice the prices go down after a time? It's the same thing, they are keeping the same profit margin, just having to sell it at a higher price to do so, then the higher priced good doesn't sell as quickly, but eventually they do get it cheaper and lower the prices again. We just notice it a lot more with fuel because there's so much talk about fuel.",
"They do track reasonably well to oil prices. Take a look a the 10 year [graph of oil prices](_URL_0_) and the (separate) [10 year graph of gasoline prices](_URL_1_). (you'll have to select the 10 year span yourself)\n\nSo...on the macro scale, they do track together. On the smaller scale pricing has to contend with immediate availability, prices of their crude in inventory, availability of refining capacity and season supply/demand etc.",
"The best answer is this, if you hold this bar of soap, now drop it, now keep trying to get it off the floor while I gang rape you in the shower. I am the gas giants. Your welcome.",
"For the most part, they are just looking for any excuse to raise the price and get away with it. It only comes back down as people start to drive less and they sell less gas."
] |
How does a linear induction motor work? | [
"Alright, the only word in there you gotta worry about is 'induction'. 'Motor' just means it moves stuff, and 'linear' just means it moves stuff in a straight line (or close to it). \nAs for 'induction': When you've got electricity moving, it can create a magnetic field (i.e. what magnets make). That magnetic field can move stuff like you could with a magnet if you work the electric current just right. How do you work it just right? Well you basically line up a row of electromagnets (i.e. magnets you can turn off and on, or those pink things in figure 23 in that pdf) ~~and turn them on/off as they move along the iron stator (basically a chunk of iron that's attracted to magnets) so that the magnets are always getting pulled forward.~~ \nThis kind of motor has two main advantages. One is that since nothing needs to be touching, you reduce friction, so things can go faster. The other is that the motor doesn't need much in the way of moving parts since it's all electricity, so things don't wear out as fast. \nDoes that help? \nEDIT: See later post. Read a few things wrong in my first read of the pdf.",
"Look at a row of movie marqee \"chase\" lights.\nIt is fundamentally the same thing, except instead of light bulbs it uses electro magnets, and the \"lit\" one draws the magnet to it, and as it \"chases\", the next one activates, drawing the magnet."
] |
Does time ever end, or is the future infinite? | [
"That's a really good question, as if deals with the metaphysical in a physical context; basically, the universe will end before time ends, so we have no real way of knowing. However, one could argue that time will end when physical existence ends; in that case, the end of time will come with the end of the Universe.",
"It’s hard to say. Time isn’t steady, it’s fluid and changes depending on things like where you are (in relation to a strong source of gravity) and how fast you’re going. If you go the speed of light, time doesn’t exist. If you go close to a super massive black hole, time can be infinitely slow. As for if time will ever end, it depends on if/how the universe ends. If the universe keeps expanding, it will get to the point where it expands so fast nothing will be able to touch anymore, at which time, time will be irrelevant",
"Well... time itself is a human-made construct, so “time” will exist as long as humans choose to use it.\n\nAs for the future in general, there’s no evidence of every type of matter ever ceasing to exist all at once, meaning it will be infinite."
] |
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