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oqeim | what is a coronal mass ejection, and how will it effect us once it reaches us from the sun? | Based on [this post from /r/science](_URL_0_) | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/oqeim/what_is_a_coronal_mass_ejection_and_how_will_it/ | {
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"It's a storm of electrically charged particals being ejected from the suns surface. Once it the storm reaches earth it will be deflected around the earth's magnetic feild and stream away into space. The most noticible effect will be incredible Northern lights, from the particles hitting the upper atmosphere. The electrical charge might also knock out some sattelites like an EMP blast. But it's not anything to worry about. They happen from time to time. ",
"To expand: coronal mass ejections happen from time to time and, as infidelwithajetpack pointed out, generally nothing happens. The earth's magnetic field redirects the charged particles to the poles, we get pretty lights, life goes on. But the concern is that a large enough mass would be enough to overload or bypass the magnetic field. This could be bad, because instead of just knocking out satellites, it could overload the electric grid on the planet. Specifically, a large enough charge could overload and destroy transformers, which are not cheap or fast to replace and, as I understand it, we don't have many in reserve because there's no other good reason to have them.\n\nFor more, see if you can find the third episode of Bad Universe."
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2m13jw | why do all online games seemingly have issues on launch day? even when they have been extensively beta/stressed tested. | Seems to be the norm now that online games... Especially big launches will be unplayable on launch day. I don't understand why companies can't adequately plan. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2m13jw/eli5_why_do_all_online_games_seemingly_have/ | {
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"It's virtually impossible to simulate the actual load on launch day. So many companies think they're hitting the sweet spot on capacity and end up shitting the bed.",
"They aren't all terrible. 343i bit off more than they could chew, that's all.",
" > Even when they have been extensively beta/stressed teste\n\nThey haven't. Few companies can accurately predict the needs OR even be able to meet them at ultra-peak times such as launch. It's better to have a shitty launch, then to invest in tremendous resources that will only be relevant for a few hours of a games lifetime.",
"A couple reasons come to mind. First, it comes down to infrastructure. Lets say an online game is expecting 5000 users on average at a given point in time, and they build the server to handle 10000 users to accomodate for high traffic times. On launch day everyone (lets say 100,000 people) is trying to get online at the same time, and the server just can't handle the traffic and it crashes. The company isn't going to invest in the infastructure to handle 100,000 people on a daily basis because eventually things will calm down and they won't need it, but it leads to trouble on launch day.\n\nSecond, even with months and even years of beta testing, you're not going to encounter every possible problem and have time to fix it before you launch. As soon as you have a lot of people playing a game they'll find bugs that the developers didn't even dream of, and that's why bug fixes will often happen shortly after a game is released. ",
"There is no testing as good as actually using the software. And for an online game that includes 10s of thousands of users at once",
"There is one more point to all of this mess with game launches to consider.\n\nIn today's world it is \"easy\" do patches in many gigs vs the early day with a much slower internet. This has led to game being released unfinished\n\nAlso in this digital age you just down load the game vs going and buying a copy. This also leads to issues."
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x84s2 | why people put "edit: explanation of edit" when they edit a post. | Why don't they just edit it and not admit to making a mistake. Is it an honesty thing? Personally I don't care if you misspelled something and want to go back to fix it. Keep it to yourself. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/x84s2/eli5_why_people_put_edit_explanation_of_edit_when/ | {
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"You write a comment, somebody replies. You can go back and completely rewrite your comment, making the person that replied to you look like an asshole.\n\nPeople know the comment was edited (this * near the name) but they don't know what exactly was changed. So some people feel oblidged to explain why/what they changed about their original post.\n\nAlso sometimes you want to say something extra long after the comment was posted (and maybe got to the top). You need to somehow mark what content was originally posted and what was added after it got to the top."
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2joz30 | if signing a contact can legally bind me to something what is stopping someone from simply forging my signature? | Contract* | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2joz30/eli5_if_signing_a_contact_can_legally_bind_me_to/ | {
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"Nothing is stopping someone from forging your signature, just like nothing is stopping someone breaking into your house and killing and eating you.\n\nOf course since you didn't actually sign the contract its not valid, the person who has the contract would have to prove you signed it if you dispute it.",
"Signing a contract does not legally bind you.\n\n*Agreeing* to the contract legally binds you, signing is evidence that you agreed. If you can provide other evidence that you did not agree to that contract, it is not binding.\n\nAlso, forgery and fraud are serious crimes. The prospect of jail time will prevent most people from resorting to them.",
"The fear of punishment is the only thing stopping anyone. Their own fear. Scary to think that's all anything hinges on, right? Also gains versus losses. If it's worth it it'll be done. "
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cj3z64 | how do wetsuits work? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/cj3z64/eli5_how_do_wetsuits_work/ | {
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"they're basically insulation. they prevent water that your body gets in contact with from flowing away and being replaced with cold water. after a few minutes the water that's being insulated will eventually settle at some temp and the wetsuit keeps out as much of the colder water as possible from contacting your skin.",
"Step 1: Submerge wetsuited body in water.\nStep 2: Wetsuit fills with water.\nStep 3: Body heats up water now trapped in wetsuit.\nStep 4: Body stays warmer than the water outside of the wetsuit. \n\nAddednum: Wetsuits typically range from 3mm to 7mm thick. Thicker wetsuits provide more protection against the cold of surrounding water."
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3fmxhy | why doesn't the federal government just fix the american internet problems by breaking up the oligopolies and actually make the isp's compete with each other? | they wouldn't need to intervene as much, they would just give the companies a run for their money, forcing them to give the best possible service for the lowest possible price | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/3fmxhy/eli5_why_doesnt_the_federal_government_just_fix/ | {
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"The major problem is that in many areas, there's exactly one option for broadband access. Breaking up companies doesn't help in that circumstance.",
"I don't know if this is the *real* explanation but it's the most common one. Congress gets a ton of campaign contributions (read: bribes) from that industry, so they're not inclined to go after them. \n\nMeanwhile, the main regulatory agencies (FCC, DOJ, FTC) are generally packed with insiders, while also being under-funded for this type of enforcement. \n\nSo while the state of the industry might be bad enough in theory for a major intervention of that type, the people involved are (maybe not \"corrupt\" per se) but unduly favorably disposed towards the industry, so don't do anything. \n\nGenerally, also, state legislatures will do whatever Comcast or Verizon tell them to do. I mean states are actually banning themselves from competing with these companies instead of addressing the problem. They're *passing laws* against additional competition! The state legislatures are so far in the ISP industries' pockets that they can probably take a sponge bath with jock sweat in there. ",
"The government cannot make companies compete with each other. If company A doesn't want to expand into area Z because they will need to invest a lot of money into doing that and they aren't sure it will pay off, what can the government do? Force a company to go? ",
"Two problems: lobbying groups have congress in their pockets. Telecom gives big money to lots of people on both sides of the aisle to keep them voting favorably at the national level. \n\nThe other problem is infrastructure. Laying cable is expensive, and lots of the US is very spread out and not densely populated, meaning you have to lay a lot more cable for access to the same number of houses. Even if we had different companies, most individuals don't have a choice of carrier, since there's only one cable line that runs to their house, they probably have a choice between cable or DSL.",
"Big business, which includes companies like Comcast, Time Warner, etc are very large political donors. It is recently rumored that Time Warner has already donated close to a half million dollars to Hillary Clinton's campaign.\n\n-\n\nI'm fairly certain that if big ISP's are helping our public officials get elected, those public officials aren't motivated to make it a better system.\n\n-\n\nThis will probably get downvoted to hell and back, but it's true.",
"The solution is to split up the companies not by geographic area, but by service they provide. \n\nThe company that owns the lines should not be the same company that provides the service on top of the lines. With the owners of the lines regulated on how much they can charge for use of the lines. ",
"That would go against your idealogical beliefs in an extreme form of capitalism. \nActually all the government has to do is force companies to share the medium of transmission. It's done in Japan and they have gigabit residential connections for $50 or something.",
"Because the American Government is not a single benevolent power that can simply apply an obvious fix to a problem. Any change has to go through the senate and the house and the president. To compound things, there are plenty of politicians in these seats that are paid off by organizations to vote in their interest instead of the interests of the people overall.",
"Because oligopolies are protected against competition by the Government. The reason is simple: ISP's first had the technology and the financial backing to invest in building a network over thousands of square miles. This required them to invest a significant amount of capital into this infastructure. Companies that provide a service that is necessary like the utilities, internet, phone, rail and airlines first establish an agreement that the government will regulate competition. The idea is to let that company invest and expand their business while making little to no money then in the future once they are making money regulate who can enter the market and compete with them. Have you ever wondered why BP/Exxon, and other large companies have advertisements that try to make the company look like a vital part of the community? They don't have advertisements asking you to buy their products. This is because public image and perception of these companies directly effects our elected leaders. If the elected leaders are feeling pressure then the government can lower the threshold for competition and allow new company's into the market place. ",
"I just wish they wouldn't actively oppose competition coming in. Several towns have tried to setup municipal ISPs usually for fiber and the existing local monopoly ISP takes them to court over it... Saying they can't compete with government funded services or something... \nBasically they can't compete with something that isn't trying to make ridiculous profit by providing the bare minimum of service for decades old Internet speed standards. "
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5uoohb | why has technology not been able to replace subjective feedback style eye exams? shouldn't we have a device by now that can just tell how bad your eyes are? | [deleted] | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5uoohb/eli5_why_has_technology_not_been_able_to_replace/ | {
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"Almost every modern optometrist will have a machine that can automatically determine your prescription. You might have used one; it's a machine that asks you to focus on a picture through a small lens. The optometrist will use the results from this machine as a starting point.\n\nThe subjective tests are still used because some people prefer a different prescription from what the machine recommends. It's completely personal preference. ",
"I'm pretty sure this exists. When I've gotten glasses outside the US I just looked into a machine at a cartoon of a tiny house and the machine made adjustments until the house was clear to me and that was my prescription. No expensive eye exam needed. I assume it's a US regulation to keep eye doctors rich and people with bad vision poor",
" > So why, given all the amazing advances in technology, do we still use this seemingly archaic system?\n\nHave you been to an optometrist recently? I haven't used one of those machines since I was a kid",
"Yep, the machine where you look at the picture of the hot air balloon at the end of the road.\n\nBut, you still have the 'A' or 'B' tests, because it really depends on what's wrong with your eyes and what you prefer. \n\nBecause of my astigmatism, I basically have to choose whether I want lenses that give me perfect up-close vision and 'okay' distance vision, perfect distance vision and 'okay' close vision, or 'good but not perfect' vision across the range.\n\nBecause I work in front of a monitor all day, close up vision is way more important than distance, so the machine can only go so far"
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4b4uwo | why didn't people on the very top floor of the wtc towers survive? | [deleted] | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4b4uwo/eli5why_didnt_people_on_the_very_top_floor_of_the/ | {
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"Because they would have either burned or fell at free fall speeds 100's of meters to the ground. ",
"They are still falling over 1000 feet, and still having the top of a skyscraper collapse on them which itself ways more than enough to kill everyone. Even if they did survive, they wind up in a mountain of rubble in a mile wide cloud of toxic ash and dust.",
"Well, for one thing, if you had to choose between one ton of material falling on you or 100 tons, well, that's not much of a choice because both are fatal.\n\nAdd to that the part about the impact on the ground (or rather, the rubble of the floors below you) and there's no way to survive.",
"How was your 5th birthday last week?",
" > coast down\n\nThe videos make it look like the tower collapses were some gentle thing, but that's only because of the perspective of the videos. Those towers collapsed violently. The people inside would have been tossed around violently inside the rubble as it collapsed, killing them likely before they hit the ground. It would have been like being in a car accident on the highway with no seat belts or airbags.",
"On all floors the internal structure of the building suffered catastrophic failures that would have thrown chunks of the building material like very lethal shrapnel as the collapse progressed.\n\nHollywood action films may have given you a false impression of the chances of surviving a massive and complete building collapse. Watch it and see how far the dust plume travelled. Bare in mind that that dust plume is thousands of tons of pulverised concrete. That's the forces involved. Thousands, tens of thousands of tons of concrete pulverised in seconds. \n\nThose that hadn't jumped, burned or died from smoke inhalation likely died of crush injuries. Or the horrible truth is that some very few may have survived the collapse only to die in the next few days as rescue crews couldn't locate them in the 1 000 000 tons of toxic rubble."
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9znvml | how do companies like amd, intel, nvidia etc make better cores? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/9znvml/eli5_how_do_companies_like_amd_intel_nvidia_etc/ | {
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"Further research into computer technology sees the transitor (a key part of a processor) getting smaller and smaller, from 22 nanometers, 20, 16, 18, 14... \n\nAs long as we are still able to shrink the transistor (until it gets too small for the basic principles of to work), companies will continue to find ways of jamming as many of them into a processor, and more is usually better."
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btplas | what is the difference between a geiger counters and dosimeters. where would you and not use them. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/btplas/eli5_what_is_the_difference_between_a_geiger/ | {
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"A Geiger counter measures the amount of ion pairs created every 60 seconds, so you can see how much radiation exists (although, a Geiger counter won't tell you *what* radiation is created, which you may want to know).\n\nA dosimeter simply tallies all the radiation it's been exposed to. So if the Geiger counter is your speedometer, the dosimeter is your odometer. One tells you how fast you're currently going, the other tells you how far you've gone."
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ffehme | what causes rugby players to get 'cauliflower ears'? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/ffehme/eli5_what_causes_rugby_players_to_get_cauliflower/ | {
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"Cauliflower Ear is a condition where the blood that collects inside the outer ear don't drain properly or get infected. This causes a hard puffiness in the ear that tends to look like cauliflower.\n\nIt's actually more common in fighting sports, like boxing, but can occur with any sort of injury to the ear, like if you trip and fall into the ground.",
"It’s usually caused by trauma to the ear, so happens a lot with rugby players because of all the tackling and scrums.\n\nWhen the ear is damaged, it bleeds between the layers of tissue. The bleed stops the cartilage in the ear from getting nutrients like sugar and oxygen it needs to survive. The cartilage then dies, and thicker tissue is created on top of it. This is what you see as the cauliflower ear."
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6cd42i | how does the earth regenerate all the water it has lost through human consumption? is it reasonable to think we will eventually run out of water? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/6cd42i/eli5_how_does_the_earth_regenerate_all_the_water/ | {
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"The water on Earth doesn't regenerate. Water is in a closed loop system. We don't gain or lose any water on a large scale. Water exists as a solid, a liquid, and a gas and there is a cycle that describes the movement through those phases. \n\nWe do have a finite supply of potable water, and to regenerate that supply requires intervention in the cycle."
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4o7slj | how does an amoeba grow/get into a space if there isn't an amoeba there to begin with? | I am reading about Naegleria fowleri (the brain eating bacteria) and the CDC says it can manifest in water heaters. Assuming water heaters aren't made with the original cells of this amoeba how does it even get in there? Does it travel like an other animal and find it's way to water heaters? Does it spontaneously grow? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4o7slj/eli5how_does_an_amoeba_growget_into_a_space_if/ | {
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" > Does it travel like an other animal and find it's way to water heaters? \n\nPretty much, yeah. Some bugs survive the water-treatment process and make their way to just about everywhere.\n\n > Does it spontaneously grow?\n\nAbsolutely not- that was a theory (for things like mold and maggots, at least) in the early modern period, but since the 1800s, and thanks to Louis Pasteur, we know that there needs to be a seed (broadly understood) for things to grow in a place.",
"The amoeba has, like quite a few micro-organisms, a tendency to form a cyst when it encounters conditions it can't survive in. That allows it to spread between sources of hot water."
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6jogng | how do cows produce milk throughout the entire year since most mammals stop after a certain period of time after giving birth? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/6jogng/eli5_how_do_cows_produce_milk_throughout_the/ | {
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"Dairy cows are often pregnant. Farmers impregnate them and then take the calves away to maintain a state of lactation. ",
"Most mammals lactate as long as their young nurses. When nursing stops, lactation stops. When dairy farmers continue to milk them, they keep producing milk.",
"Human mothers can nurse for years. There are (rare) stories of mothers nursing children until 5,6,7 years old and beyond. A human mother does not just run out of milk, she has to decide when she's finished nursing at which point the breasts will become extremely engorged for a couple of days before the body reabsorbs the milk. It's a use it or lose it scenario with the milk. \n\nThat being said the safe assumption would be that as long as the farmer continues to milk the cow, it'll just keep coming. A good milking should be a big relief for a full cow as nursing is for a mother after several hours. ",
"Cattle (and milk goats) have been selectively bred to keep producing more milk for longer spans of time after giving birth. They _do_ still need to give birth to get the process going however, and milk production rises and then declines as time passes after birth. Here's a website that describes the cycle\n\n_URL_0_\n\nA cow not bred for milk production would wean a calf more quickly than indicated. As the link below notes, in beef cattle 60-70% of milk is produced in the first 60 days, whereas the previous link shows that dairy cattle will produce milk for much longer than that\n\n_URL_1_",
"Dairy cattle don't produce milk all year unless we force them to.\n\nOkay - here is how it works. Typically as long as you milk an animal it will continue to produce milk. \n\nImagine a human mom - she has a baby, she decides to nurse the baby. Her milk doesn't \"dry up\" until she decides to stop nursing the baby (unless she is in bad health, poor diet, or so forth). In the past it was not uncommon for human mothers to nurse their children until the kids were 4 years old.\n\nOr maybe the mom decides she doesn't want to breast feed and puts the kid on a bottle at the start. She stops producing milk after a few days.\n\nThe same with cattle. The cow produces milk as long as it is being milked. In the dairy industry we take calves away and hook momma cow to a milk machine twice a day. We feed her good and give her lots of water and she could be milked for over a year if we wanted to. However.. farmers don't do that. Instead they milk her for several months (in which time they rebred her often using AI) and then stop milking her only a few months prior to her having her next calf, and then the cycle continues.\n\n",
"Cows don't produce milk for an entire year, however dairy cows are bred and sometimes given hormones to lengthen the cycle. Normal cows lactate from birth usually in spring to the fall which is actually shorter than some other mammals like humans. Dairy cows are shorter too but they get up to an average of ten months. They still have to have a baby every year to keep producing milk. Thus if the baby is female they raise it on the lot and forcibly inseminate it shortly after their first birthday so they can be a dairy cow and repeat that process for 4-5 years until they start having reproductive problems and go to make hamburger. If in the females lifetime they have a male they of course are the privileged ones. They get the mercy of only knowing their mother for a day, getting sweet release after only 3-18 weeks, and getting to be veal which is so much classier than hamburger. \n\n\nI am discussing some of the absolute worst conditions possible for dairy cows, and there are some farms that still practice more natural methods. But the vast majority of dairy cows exist in the worst possible conditions. "
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3bcee5 | why have there been so many shark attacks in the outer banks this summer vs the past? is it safe to swim? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/3bcee5/eli5_why_have_there_been_so_many_shark_attacks_in/ | {
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"Quite frankly, I'm not sure that there is enough data at the moment to conclude anything concrete; it is still summer, which means it is still tourist season. Is there an influx of sharks and attacks, or maybe just an influx in tourists this year, resulting in more incidents? Too early to tell. \n\nThe first thing to remember is that the Outer Banks is a stretch of about 200 miles of coast line. This isn't a single, pin point on a map. It's not like this one singular beach has all of a sudden become a shark feeding ground. \n\nWith that being said, sharks have always been common in the area. [Here's a picture of a hammerhead from two years ago that I took.](_URL_2_) The guy in the picture caught him while shore fishing. [Even back in April, the local news outlets were reporting Great Whites](_URL_0_) in the area via _URL_1_ . I would actually highly recommend taking a look at their data. Go back in the past month and past year to see how close some of these sharks are surfacing to the shore line. There are some that have even been pinged inside the sound. To think, these are only the ones that tagged and being tracked. \n\n[This site](_URL_3_) can give you a pretty good picture of historical shark attacks in the area. Sept 3, 2001 shows two shark attacks in the same day - one of which was fatal. There a multiple dates where shark attacks have occurred on back to back days. A cursory glance looks like NC averages about 5 attacks a year. In the 2000s, 7 was the highest I saw. So, we may end up being slightly above average this year, but it is (at this point) maybe not potentially alarming. I think the other thing to note is that the frequency between incidents probably doesn't mean a whole lot. \n\n[This site](_URL_4_) maps out shark attacks. I didn't spend a lot of time on it, but it doesn't look to be completely up to date for 2015 attacks. What I do find somewhat curious it the four attacks within days and ~5 mile stretch of beach of each other in Cocoa Beach Florida that were not covered by the media as much as the bites in North Carolina. \n\nIf you are planning on visiting the beach this year, brushing up on safety tips is a good idea. I no longer live in the area but was always told a couple of things. First, swim in groups. Being alone will make you an easier target. Don't wear jewelry in the ocean as it can be reflective, similar to a fish's scales. Try to avoid brightly colored, geometric patterns on swim wear for similar issues. Don't swim out to sand bars, and avoid swimming near piers or where people are fishing from the shore. They are attracting bait, and you are just another piece of meat. Finally, I have no idea whether or not there is truth in this statement, but normally when you see a pod of dolphins it means sharks are near. Again, think food. "
]
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"http://hamptonroads.com/2015/04/two-great-white-sharks-along-our-coast-more",
"http://www.ocearch.org",
"http://i.imgur.com/V4p1v6q.png",
"http://www.sharkattackdata.com/place/united_states_of_america/north_carolina",
"http://www.trackingsharks.com/2015-shark-attack-bites-tracking-map/"
]
] |
||
1w0y3k | why does my hair get more oily than usual, and faster than usual when i'm very tired? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1w0y3k/eli5why_does_my_hair_get_more_oily_than_usual_and/ | {
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"Perhaps you touch your head more at those times? Running your hands through your hair, massaging your head, etc.? I really have no idea, but it seemed logical."
]
} | [] | [] | [
[]
] |
||
6ihp6n | why does car sickness seem to hit the hardest when you look down at your phone, book, etc.? | [deleted] | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/6ihp6n/elif_why_does_car_sickness_seem_to_hit_the/ | {
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"Because what you are looking at is moving, even though you feel like you're sitting still. \n\nHaving your visuals moving when your brain thinks you're not leads your brain to think you've been poisoned. So your body, which has evolved to puke up things you may have eaten that are poisoning you, goes to that as a default.\n\nIt hasn't caught up to reading in the car yet. \n\n_URL_0_",
"There are a few different causes for motion sickness, but one very common cause is the disconnect between the motion your body feels and the motion your eyes see. \n\nWhen you're in a moving car, your body feels the motion, if you closed your eyes you'd know you were moving by the sensations on your body and a special configuration of your inner ear that can detect motion. \n\nHowever, if you are a passenger and you are only focusing your eyes on something inside the car, your eyes don't see the motion your body feels. This disconnect between different sensations of motion and non-motion creates a confusing sense of movement in your brain, which can cause nausea if it goes on long enough. \n\nIf you focus on something outside the car, your eyes and your body's other senses of motion have similar experiences of movement, so the disconnect doesn't happen. \n\nPeople who are prone to this type of motion sickness can experience similar motion sickness if they watch a movie with lots of camera movement, because their eyes are seeing motion while their body doesn't sense it. "
]
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"http://www.sciencealert.com/here-s-why-you-get-car-sick-your-brain-thinks-it-s-being-poisoned"
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|
893t5q | what's the difference between typical linux hosting and "wordpress hosting" that hosting companies offer. | That's that. Or is there really a difference? Is it just a marketing practice to appeal the ordinary person that has no idea about hosting other than wordpress?
Wouldn't it also be possible to use your own Wordpress based website on a typical Linux hosting with Cpanel and MySql, providing PHP support and all? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/893t5q/eli5whats_the_difference_between_typical_linux/ | {
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"It depends on how much control/responsibility the customer wants.\n\nIf you want a simple blog, it makes sense to buy from a company that provides that. You get a blog with minimum fuss.\n\nIf you want full control over your own server, so that you control all of the software and updates, it makes sense to buy from a company that provides that. It's a lot more work, though, since you need to keep the servers updated, configured, backed up, and so on.",
"Usually if someone offers \"wordpress hosting\" they're offering a setup where once you pay them, you have your own Wordpress instance setup and ready to go, little effort required by you. This is a preferable option for people who are less technical: you get to \"the good stuff\" that much faster and have less to learn. If you're trying to have a web presence for your mom 'n pop plumber shop this is probably the way you'd go.\n\n\"Real\" Linux hosting gives you more bells and whistles, but with great power comes great \"oh shit what did I do that just broke everything and I don't know why!\" \n\nSo partially marketing, partially some pre-baked stuff for users who are okay with vanilla.",
"an environment where they're optimized for wordpress will be better for wordpress than a general linux environment. you tweak the webserver and application server settings and memory settings to match what best suites how the wordpress application is implemented. because wordpress doesn't run the same as drupal, magento, joomla, etc etc"
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6lopub | how so called natural male enhancement works. asking for a friend. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/6lopub/eli5_how_so_called_natural_male_enhancement_works/ | {
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"Natural male enhancement works due to the inherent insecurities of many men about the size of their genitalia, and associations that they have between this size and their masculinity. Insecure men will pay lots of money to \"fix\" what they see as a problem with their genitalia. The pills don't do anything. You'll notice that none of them are FDA approved, which is generally a good sign that a supplement can't produce any measurable results and is a load of crap.",
"They don't. They claim the placebo effect. They do nothing at all but take money from insecure men. They make millions and millions. Just like all the \"dietary supliments\". They only have to prove they do no harm.",
" > but the stuff that claims to enhance ones package. Seems unrealistic.\n\nOf course it is unrealistic, if it worked there would be an aisle in every drug store and gas station in the country dedicated to such products.\n\nThe only effective enhancement I know of is for length which is achieved by cutting a supporting ligament for the penis. The result is a longer but poorly supported erection, which you can easily spot in porn if the male star gets hard but the penis tends to point every which way unless guided by a hand. Other than that surgical procedure with some drawbacks I don't think there is another reliably effective enhancement."
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2fwp69 | when an uninsured patient arrives in the emergency room and is treated (by law), and that patient can't pay for the treatment, how does the cost of that treatment affect tax payers? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2fwp69/eli5_when_an_uninsured_patient_arrives_in_the/ | {
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"It increases the costs for the hospital, and they pass that cost (usually) onto insured people. So since most tax payers are insured people, they pay for the cost by increased insurance premiums.",
"The standard procedure for a private hospital (which make up the vast majority of hospitals in the U.S.) is to provide stabilization as required by [EMTALA]( _URL_1_) and then transfer the patient to a [public hospital]( _URL_0_) to receive care. Public hospitals are funded almost exclusively from tax revenue, through a combination of Medicare/Medicaid reimbursement for services and direct funding from local government. \n\nRural private hospitals are different because they rarely have a county hospital to transfer to, so they are more likely to cover uncompensated care by charging higher rates for compensated care."
]
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[],
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"http://en.wikipedia.org/wiki/Public_hospital",
"http://en.wikipedia.org/wiki/Emergency_Medical_Treatment_and_Active_Labor_Act"
]
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||
1tlkrq | why is reddit text formatting so terrible when you try to start a new line of text? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1tlkrq/eli5_why_is_reddit_text_formatting_so_terrible/ | {
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"I don't know why. \nBut if you want to start a new line you should end your line with 2 or more spaces before pushing enter. \nLike this. **(Space) (Space)** **(Enter)** \nAnd your new sentence will start on a new line. (without an empty line)\n\n\n"
]
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||
1735oj | why do almost all wikipedia articles look like they are written the same way? | There is a certain "way" that Wiki articles are presented, and it is just curious to me as to why. I know that many are professionally made, but why does this happen when it can be edited by anyone? This also happens elsewhere, so thanks for any answers! | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1735oj/eli5_why_do_almost_all_wikipedia_articles_look/ | {
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"You have to remember that the people who take time out of their day to write for Wikipedia are often people who care.\n\nThat said, every information site has a specific \"style\" that people write in, and people who care would generally want to make their work become part of a bigger thing.\n\nThose articles that don't conform are usually fixed, if it has any informational value, by another good person. ",
"There are style guidelines for articles, which were created by the community over time I think and refined by editing just like the rest of the site. There is a massive community of people who care about it working behind the scenes. This creates an aura of respectability around the site, meaning that people who don't actually care about the subject rarely edit a page, and people who do care about the subject care about their edits being kept. And if the content is good but the style doesn't conform, it is likely to be edited by somebody who's interested in keeping the style consistent.\n\nIt's important for a website like wikipedia to be coherent and consistent. That's why it is so successful. There are a lot of people fighting to maintain it, and it works."
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1v06un | why has no country "invested" in africa yet? | Or alternatively, what can we expect from the African continent (perhaps not including South Africa) in the future? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1v06un/eli5_why_has_no_country_invested_in_africa_yet/ | {
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"China is currently buying up vast plots of land. I guess you could say that it's investing in it. But do you really think they want 'white men' having power there again?",
"They did - it was known as the Scramble for Africa.",
"There is a ridiculous amount of investment in Africa. Billios of dollars are going in from all directions. China has built almost all the roads of Mozambique in exchange for preferential business partnerships, Internatinal companies have invested in mining, drilling, construction, etc, and the countries in Africa that are growing are doing so at a better pace than countries almost anywhere else. \n\nAfrica is high-risk high-reward. \n\nThe head of McKinsey consulting gave a speech to my MBA class a coupe years ago and his main message was: commodities are going to get more expensive and Africa is going to grow more than any other continent on the planet. If you want to get rich, move to Africa and don't build a business that assumes oil and minerals will stay cheap. "
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34ogmh | if two partners have dominant genes that contradict each other, what would happen to the baby? | For example: If I had a dominant gene for a small nose, and my partner had a dominant gene for a big nose, would our baby just have a very regular sized nose? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/34ogmh/eli5_if_two_partners_have_dominant_genes_that/ | {
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"'Dominant' and 'recessive' are the highschool version.\n\nIn reality, one of your two sets of traits would be more dominant than the other.",
"You can't have two different dominant alleles of the same gene. That is what 'dominant' means. If one is dominant, the other is recessive. If you did have such a system, you would use different terms to describe it. Like how ABO works in blood typing."
]
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5l37wf | if the universe doesn't have borders, will an object travelling forever in a linear motion eventually arrive back on its initial spot, or will it keep on distancing itself from it without ending? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5l37wf/eli5_if_the_universe_doesnt_have_borders_will_an/ | {
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"We don't know if the universe has borders, it likely doesn't afaik.\n\nWhen you hear the universe is expanding it doesn't actually mean what you think it means. \n\nIt means the graph paper itself is expanding. ",
"Good question - we don't know for sure.\n\nBut, actually, it probably doesn't matter. If the current expansion of the universe continues, you would keep traveling in a straight line forever because the space ahead of you would keep expanding away from you.",
"Firstly the universe is either finite or infinite, we don't know which.\n\nIf it's finite it either has borders or it doesn't, we don't know which.\n\nYou're assuming it has no borders. Meaning either it is infinite or it is finite but a closed loop. In other words the 3d shape of the universe curves through 4d space so that while the amount of space might be finite there is no edge.\n\nIf the universe is infinite then an object travelling forever in linear motion will just keep on getting further away.\n\nIf the universe is finite but unbounded then an object travelling forever in linear motion might eventually arrive back at its initial spot but it depends on the topography. You might end up three feet to your initial left and draw out an infinite but never-repeating spiral. There are lots of ways [to have an infinite curve on a finite plane](_URL_0_)\n\nIf the universe is finite and unbounded and topographically simple enough then yes object travelling forever in linear motion might eventually arrive back at its initial spot but the object might not have enough time to do so. Even if the object is a photon it can only travel at the speed of light and the distance it has to travel is unknown but has to be at least many hundreds of billions of light years. And it is not guaranteed that the universe will last hundreds of billions of years.\n\nIf the universe is finite and unbounded then the universe will probably end in a big crunch. How long this takes depends how big the universe is, but either way there probably isn't time to do a lap.\n\nThere's some theories that suggest that if there's enough dark energy in the universe then even if the universe is finite and unbounded the big crunch can still be avoided. So then we're racing against heat death. If the object is anything other than a photon it will decay within 10^100 years which might be enough time to do a lap of a small universe but nothing big, and even if its a photon it will decay (be annihilated) eventually.\n\nTl:dr depends how big and bendy your universe is but probably not.\n\nEdits:\n\n- thanks for gold\n- yes I meant topology, although I'm not 100% convinced that my usage of topography was totally wrong\n- I cheated/simplified a little by folding in the whole factor of if the universe is expanding and at what rate into the question of its infiniteness/shape but this doesn't make any substantive difference I can see to the answer to the question\n- Yes the universe probably is flat, and infinite/expanding so fast it is effectively infinite. But if that is the case then ops question becomes boring and trivial, so I'd rather explore some of the more interesting possibilities.\n- Thanks for all the comments, sorry I didn't reply to all of them but I tried to reply to most that weren't repeats. If I didn't reply to you it either means I missed you, I answered someone who was saying something similar, or your question had me so stumped I couldn't think of an answer.",
"The object will continue traveling farther away forever. But that has nothing to do with whether the universe has borders or not.\n\nThe visible universe is expanding, and it's doing so faster than the speed of light (before anyone objects, that doesn't mean matter is traveling faster than light, just spacetime). We don't know what's beyond the visible universe, and for the most part it would be impossible for us to ever know. Because of the expansion we can never reach the edge of the visible universe. Even traveling at lightspeed for eternity, the portion of the universe any object could actually reach is steadily shrinking.",
"Imagine a two-dimensional creature living in what it can only sense is a two-dimensional physical universe. What it cannot comprehend is that it actually lives on the surface of a massive three-dimensional sphere. It can never get to the center of its universe because the center is straight down, and up-and-down is a third physical dimension, one of which it is unable to comprehend because of its flat, two-dimensional nature. So, if it travels in a straight line (a great circle), it will return to the point of origin. And its universe is expanding, like a balloon blowing up. \n\nI imagine the same is true of our universe, only with one extra dimension. We are three-dimensional beings living on the surface of a four+ dimensional universe (physicists posit that there are ten physical dimensions, but I have a hard time grokking it). So, if we travel in space in a single direction, we would also end up right back at Earth. And our universe is expanding with the center of expansion being along a dimension(s) of which we cannot conceive.\n\n**Bonus mindfuck:** As the two-dimensional creature's universe expands, the surface area of its universe increases. Each point on the sphere moves away from every other point on the sphere. New 2D space is created as the sphere expands. The same is true for our universe; as our three-dimensional universe expands, every point in space moves away from every other point, and new space is constantly being created.\n\n**Super Bonus Mindfuck X-treme:** \"Now\"...what you conceive of as the present moment...the center of your consciousness...is new time being created by the expansion of the universe in a similar way to how new space is being created.\n\n*[This was my understanding of UC Berkeley Prof. Richard Muller's explanation.](_URL_0_)* I'm not just making shit up, downvoting-type-persons.",
"I thought they had said the universe, or the space in the universe was expanding. So if an object is travelling in a linear motion, it would be technically in the space that is expanding, so it would keep going forever? Or at least until the space between the universe ceases to expand?",
"If space is finite and has a border, what is the difference between empty space (no matter contained) and whatever is beyond the border?",
"OP I would suggest posting this in askcience or askphysics, in fact searching those subs would probably get you some decent responses. There's a lot of interesting musings in the responses but people are playing fast and loose with physics jargon without really understanding it.",
"All the answers can be tl:dr as such :\nWe do not know and any answer is a make believe answer there are no knows about this. And it's all speculation. We have no clue what the universe is , how it began , when it will stop , what the nature of it is , if it has a real beginning or an end , we don't know if there is an edge , if it's an expanding bubble etc. It's all speculation. Any answer beyond \"i don't know\" is is fake as hell. Here be dragons! ",
"Lol, you actually think people know the answer to this?",
"If all we knew about the universe was that it has no boundaries, it would be impossible to answer your question. Maybe an object would return to its original starting place (if the universe is sufficiently small and doughnut or sphere like) or it would continue forever (if the universe is infinite).\n\nBut we do know more. Below I try to outline the logic best I can based on the evidence we have.\n\n[We know, for example, that the universe is expanding at an ever-increasing rate.](_URL_1_) So a star 90 billion lightyears away from us today will be further away in the future. \n\nWe also know the universe is a finite age: about 13.8 billion years. So a finite age, combined with a fixed speed of light means the universe *we can see* is definitely finite. [It's the part of the universe from which light has had time to reach us in the last 13.8 billion years.](_URL_0_) Since a point that was 13.8 billion lightyears away from us is now further away, due to expansion, the observable universe is wider than 13.8 billion lightyears. It's actually a sphere about 93 billion lightyears in diameter. \n\nFinally, we know that, as best as we can measure, the curvature of space (as a *slice* of *spacetime*) is flat. Spacetime as a whole is curved, but a slice of space at a given time, on average over the whole universe that we can see is not. This tells us that the universe can have three shapes:\n\n1. Infinite and flat\n2. The three-dimensional version of a doughnut, which can be flat (weirdly enough).\n3. The three-dimensional version of a sphere, but *really* huge so that it looks flat to us. (Think about the surface of the Earth. From space it looks curved, but your bedroom looks flat.)\n\nIn the case of scenario 1, you travel forever. In the case of scenario 3, the universe is already too vast, a spaceship could not beat the expansion.\n\nIn the case of scenario 2, however, it might be possible for a spaceship going in a straight line to return to its original position. It would have to be traveling fast enough to beat the accelerating expansion of the universe, however. We know the radius of this torus must be larger than the observable universe because otherwise we'd see that stars on one side of the sky are the same as on the other side of the sky. (Since tests of this have been done.) I don't have the numbers at the moment, though. ",
"It's finite according to what we know about physics right now and will arrive back at the initial spot.",
"This topic just came up on NPR this week. They talked a little bit about what /u/KnockoutCPFreshmart mentions.\n\n_URL_0_",
"Imagine you are floating inside a balloon and want to travel to the edge. Now imagine that somebody is blowing up the baloon faster than you can travel. You will never reach the edge as it moves faster away from you than you can travel towards it.\n\nThat's the situation with our universe right now. ",
"I'm confused about the top posts that are getting gold. The answer is no, you won't EVER get back to your initial spot when heading in a single direction.\n\n\nPopular scientific belief is the universe is expanding in every direction, from all positions, at the speed of light. In theory, the center of the universe is the entire universe. *It doesn't matter* if the universe is infinite or finite. Why?\n___\nWe'd have to travel at light speed to even MATCH the expansion rate of the universe. We can travel for 1 billion years at light speed, and not get a centimeter closer to the end of our universe. Yes, we'd be further away from Earth, with additional distance from Earth, considering it expands in all directions, not just the directions you're traveling in.\n___\n\nTl:Dr\n\nOur universe is not Pac-Man.",
"No expert here but to me it's like the whole universe is in an immense object and we are on the inside surface of it.",
"\"The universe is shaped exactly like the earth, if you go straight long enough you'll end up where you were.\" -Issac Brock, Modest Mouse.",
"In Euclidean, traditional 3-dimensional space as most are familiar, the universe is expanding and for sake of this example imagine it [the universe who we will call Frank] is spherical in shape, although it is much more likely decahedral but that's another post...\n\nSo Frank is an ever-expanding sphere of contained matter and more importantly \"density\" or mass. So this mass has movement, direction, and although we haven't the computational capacity currently at our disposal, Frank has a \"measurement\" albeit very fat.\n\nSo fat Frank is ever-consuming, spherical blob of existence surrounded by other fat universes like Susan and Henry. Nobody likes Henry though.\n\nSo how does Frank keep eating? Well at Franks' and all universes' centers are massive black holes...we're just gonna say Frank is always hungry...since he's fat.\n\nFood (matter) longs to reach black holes so Frank keeps eating and expanding to satisfy his eternal struggle. \n\nFrank has an eating disorder...we call it Entropy. So what happens when either Frank has no more matter to consume or his hunger outgrows his consumption? Then we have a collapsing universe which is theorized to end with the zero death of the universe. Frank starves and dies.\n\nGood news. None of that is fun. Quasars are fun.",
"So many universe \"facts\" in here. Most of these comments are pure speculation but are written as if there were proven facts"
]
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||
1q52jr | why isn't the human race getting more and more attractive? | Science is not my strong point and this question puzzles me.
People of all levels of attractiveness reproduce, but it seems likely to me that the MOST attractive people are somewhat more likely to reproduce than the LEAST attractive people. This suggests to me that the physical features which make people conventionally attractive should be passed on more and more frequently, resulting in a progressively more and more attractive populace.
Why isn't this the case? ...or is it? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1q52jr/eli5_why_isnt_the_human_race_getting_more_and/ | {
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"There are different conceptions of beauty, and a lot of them are just cultural, not genetic. Being fat was all the rage once upon a time, and there are still some devoted to the more rotund. In some places a tan is considered great, in others a deathly pale is what gets people going. ",
"Physical attractiveness is not determined by genetics-plenty of hot people have \"ugly\" kids. DNA & genetics are the lottery of the human race, and there's no predicting their outcomes. Just look at all of the celebrities who have average to below average offspring on the general physical attractiveness scale. We're all a big hot soup of DNA & genes.\n\nI believe beauty is in the eye of the beholder, and comes from within, which is not something people obsessed with physical appearance usually care about.",
"\"Attractive\" is a relative term",
"I am going to have to go with latent genes. Even if two attractive people have children, it is not guaranteed that their offspring will also be equally attractive. Also, I would say that the percentages go against this happening (the increasing of attractive population). In my opinion, there are significantly more average looking people that the \"perfect\" and therefore not enough to effect change on a large scale. Additionally, the definition of what is attractive/unattractive seems to vary through history, A change in societies views could easily make it where the attractive people of today are the unattractive of tomorrow. ",
"2 points ... 1) Have you seen pictures of people from back in the day, especially pre-WWI or WWII? There were some strongly ugly people. And for example in some cultures appearances have been changing and evolving, for example in the Asian region, which has been experiencing the \"Americanization\" of their features.\n\nThe second point, as to why pretty people aren't more common... Attractive people tend to be successful. Successful people have been reproducing less (in all cultures) for quite some time. Meanwhile, the Honey Boo Boos of the world all have 11 brothers and sisters and 15 cousins.",
"Because nutrition, medicine, safety, and grooming have a lot more do to with being attractive than genetics.\n\nAnd because of all those things, we have gotten way more attractive over time, and continue to do so.",
"The most \"attractive\" people are actually opting for adopting other people's children (Bradgenlina etc)",
"My favorite colour is blue, blue should be everyone's favorite colour!",
"I have three thoughts:\n\n- It is the case, to some extent, but not for the reason you ascribe to it.\n- Latent genes.\n- A lack of survival pressure.\n\nNatural selection doesn't really choose the *fittest* (as they tend to say, 'survival of the fittest'); it just filters out the unfit, and leaves alone the **fit enough** to survive.\n\nIn order for beautiful people to dominate, there needs to be a clear survival/reproduction advantage over the non-beautiful people, this could happen in two ways I can think of right now:\n\n- Pretty people get to have more kids\n- Pretty people get to have more chance at having kid(s)\n\nSince neither of these advantages is really pronounced in various societies across the world, their \"positive\" trait doesn't really do them any good evolution-wise."
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497v4r | why do some artists make alter egos of themselves (e.g, eminem/slim shady, beyonce/sasha fierce, christina aguilera/xtina)? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/497v4r/eli5_why_do_some_artists_make_alter_egos_of/ | {
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"For Eminem, it's because he was in a rap group which needed more memebers, so Slim Shady was born. The other two made alter egos because they wanted to, they wanted to do stuff which didn't necessarily fit their previous image.",
"The reasons vary between individuals. Maybe they don't like their name or think that it won't be as catchy. Marshall Mathers just doesn't roll off the tongue like Eminem (holy shit I get it now, EMinEM like MM) does. ",
"Marketing. It's a way to frame a theme for their art. It's not a recent thing either. See Luke the Drifter (Hank Williams), Ziggy Stardust (Bowie), etc.",
"It's marketing. Behind every popular entertainer is planned marketing. Entertainers rebrand themselves because at their core, they are all business people and their brand is what they own. When they rebrand themselves, it allows them to hit a different demographic or do something differently to stay more relevant as an entertainer. "
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1emfk6 | ebay bid sniping | I have a few friends who eBay a lot and always watch their bids at the last second to prevent themselves from being sniped.
Now, I don't use eBay a lot, but a few years ago I did and I distinctly remember a feature where you can declare the maximum you are willing to pay and eBay would automatically increase your bid to be the lowest possible amount beneath your cap to win. So if you put $500 limit on a $200 item it'd make your bid $200, and if someone else bid $210 your bid would be automatically increased to $215, but if someone bid $501 then you're out of luck
Wouldn't this defeat the need to outsnipe an auction, is this feature no longer possible or is sniping completely different than what I think? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1emfk6/eli5_ebay_bid_sniping/ | {
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"Yes. If people bid on eBay rationally, sniping wouldn't be an issue. A rational person would simply say 'this is the maximum I'd pay, so that's what I'll set as my maximum bid' if you overbid me a day before or a second before, it doesn't matter, I'm not willing to pay anymore anyway. \n\nThe thing is, people are not rational or perhaps don't understand how eBay works. A lot of people just bid what price they hope they can get the item for, not their actual maximum bid. This is obviously stupid, but what can you do?\n\nAnyway, I always snipe because it's cheaper and perhaps I can help the world to become a more rational place. Mostly because it's cheaper.\n\nTl;dr: you're right, but people are stupid ",
"Ebay current bid amounts are $1 to $5 or so higher than the second-highest bid. Few people seem to understand how this works and it's not hard to use their ignorance to your advantage.\n\nThe Ebay audience seems to be dominated by nibblers, those who think they can pay the lowest amount possible by steadily increasing their bid. They see anyone who is willing to pay more than them who places their bid late in the auction as a sniper. The only rational way to buy something on ebay and outwit the nibblers is to bid the most you're willing to pay at the last possible second. Placing this bid early on aids the nibblers, as they keep increasing their bids until they run out of enthusiasm. I usually win by bidding an oddball amount like $152.87. This will beat the people who think bidding $151 will beat the people who bid an even amount like $150."
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3v7aj5 | how are opec and debeers allowed to control the prices of such commodities as oil and diamonds? is it unfair market manipulation or is it the best way of doing things? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/3v7aj5/eli5_how_are_opec_and_debeers_allowed_to_control/ | {
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"This happens, to a large extent, because neither of these markets is a free market; rather, they're governments under heavy government intervention.\n\nOPEC is made of governments who tell people \"oh, so there's oil under your property? That oil does not belong to you, it belongs to us.\" So it is governments who decide when to throw prices way up or (like they are now) way down; they don't care about making a profit in their oil operations, because they have other sources of revenue (taxes). So they can operate at minimal or negative profit margins (making losses) to harm their enemy governments - this is what Saudi Arabia is doing right now against Iran, which is why oil is currently so cheap.\n\nDeBeers had a monopoly under the South African apartheid regime. Diamonds are also included in the \"what's below your land is not yours but ours\" that most governments do."
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2uxwsv | why are things with exoskeletons so strong? | I have seen videos of mantis catching mice and small birds and holding them in the air. Ants carrying more than their weight. Flees, spiders, grasshoppers all jumping ridiculous distances. Are this muscles stronger or is something else going on? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2uxwsv/eli5_why_are_things_with_exoskeletons_so_strong/ | {
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"Look up the cube square law. Basically, a muscle's strength is determined by is cross sectional area, which is some dimension squared. An animal's mass is proportional to its volume, which is some dimension cubed. So, if you scale something up x times, it gets x^2 times stronger, but x^3 times heavier so its relative strength is much lower.",
"/u/mephysteaux is correct, but I wanted to make some additions.\n\nExoskeletal creatures come in two types: arachnids and insects.\n\nInsects have a central 'thorax' that does not contain internal organs other than the digestive tube. All of their limbs extend from there, a giant muscle mass in the centre of mass. Like if your chest could be 100% muscle instead of just the top coating, you would be a lot stronger. That's some core strength right there.\n\nArachnids take is a step farther and actually mount their mouths in the middle of that chest, having no heads. This 'cephalothorax' as it's called is bigger and stronger and doesn't need to dedicate any part of itself to keeping a head attached, letting even more muscle pull on the arms."
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blinln | why paper towel get hardened after getting wet then drying ? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/blinln/eli5_why_paper_towel_get_hardened_after_getting/ | {
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"It's most likely because some paper towels actually dissolve in water. They're made to have a lot of air pockets, but those are mostly melted into a solid piece when you add water and leave it"
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2xivrq | how do people become better at things than others? as in say you had 2 people practice the guitar 3 hours a day, 7 days a week, chances are one would become better than the other. what causes this? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2xivrq/eli5_how_do_people_become_better_at_things_than/ | {
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"I'm sure someone can improve upon my thoughts but I imagine it has to do with the development of different parts of the brain in combination with some other things. \n Using your guitar players as an example, I'm sure that the one who ultimately \"plays better\" has parts of their cranium that are more developed that correspond to musical talent, whichever they may be. ",
"I think there are many factors at play here, possibly too many to take into consideration. However, using your scenario, inherent ability plays a major role. Some people are born with things like perfect pitch and very good hand eye coordination and good memory skills, making guitar playing easier. Things like motivation also are important.",
"As someone who is in a unique position by having played guitar 3 hours a day, 7 days a week for 13 years, I can put my guess in...\n\nFirstly, 3 and a half of those years includes a degree in music, which means that I'm confident in my answer. A lot of it is due to **approach.**\n\nThe way I think of the guitar is different to the way another might think. In my head I relate music theory to play predominantly on-the-fly. This means that I can listen to a song once and play it from then on because I can determine when a 5th of the key we're in is about to play, I can play the 5th in as many different ways as I'd like and even improvise a lead lick in using the notes in that mode. All this means is that my approach to the guitar is a different thought process than someone who isn't proficient in music theory.\n\nSome guitarists would have spent the same amount of effort as I have, but instead they would have focussed on learning covers entirely shying away from the theory of music. So his approach to the guitar is much different to mine. Where he plays the 5th fret on the D-String, I instinctively see that as a G note, and because of that I can achieve much more given that knowledge. I think this would apply to anything that is art related, physical endeavours like caving or dancing I think require a certain physical prerequisite. But I've taught friends how to play in 1 year the same skills that take others decades to unravel themselves by teaching a certain approach to the guitar.\n\nEDIT: Pure interest and motivation into your endeavour helps too!"
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w9nut | (possibly eli12): taylor series | What is it? What does TS do? How? Why are they(?) so popular? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/w9nut/eli5_possibly_eli12_taylor_series/ | {
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"Okay this won't be ELI12, but more like ELI16:\n\nYou have a function that has a variable and produces an output. Now imagine that it's hard to calculate the value of the function for an arbitrary value of the argument. If you know you need the function only in an interval of the argument, you can use the taylor series.\n\nWhat you do is, you take a fixed value for your argument and calculate the function. Now you derive the function at that same value for the argument. You of course now have 2 things:\n\n*) The value exactly at your argument\n*) The approximate rate at which the value changes when you change your argument\n\nThis enables you to get values around your pre-calculated value very fast. However, the results will be slightly off and be more off the more you deviate from your pre-calculated value. But you can do this again and modify the tanget so it curves along the function. This increases the precision and range in which the taylor series produces almost the same values as the original function.\n\nTake a look at a (not perfect) example:\n\n_URL_0_\n\nSee how by adding the terms the green curve is layering over the blue one and how with each term the range where the 2 are almost the same increases? This is what the taylor series does.\n\nNow how is this useful. Remember, that for some functions, calculating the exact values can be hard. And some times, you are only interested in certain intervals. The values of a taylor series are very very easy to calculate. This is why you might need it.",
"Polynomials are wonderful. They are, in many senses, the simplest possible functions. We can do just about anything we want with them. \n\nAlmost all functions are not polynomials, but are much uglier and harder to deal with. \n\nWhat Taylor series do is allow us to approximate any differentiable function with a polynomial. This is extremely useful not only for approximations and numerical estimates.\n\nIn addition, the same technique applied to an infinitely differentiable function produces an infinite series which equals this function on a given interval. Again this can be much easier to work with than the original function.\n\nAs an example, an area in combinatorics called generating functions has to do with building functions whose taylor series have a given sequence as coefficients. If you compute the taylor series of 1/(1-x-x^2 ), for example, you find the fibonacci numbers. This is a powerful technique which allows much analysis that wouldn't otherwise be possible.",
"Taylor series are like taking a really complex sentence and putting it in simple words. The meaning might not be quite the same, but it's very close, and often it's good enough. Most importantly, it's much easier to figure out the simple sentence. If you want, you can try to be more and more precise, and eventually you get the exact same result as the original sentence (or for Taylor series, the original function). This is the \"approximation\" idea people have been mentioning.\n\nTaylor series also have a use in mathematics for proving very unusual things that otherwise don't make sense, like [Euler's Formula](_URL_0_). You might read that and go, \"what does that even mean?\" Even if you're in college and you know what sine, cosine, e, exponents, and i all mean, the formula *still* doesn't make any sense. With Taylor series, we can prove the formula, and it actually has real meaning - it's telling us \"there is a perfect relationship between all these different parts of mathematics\"."
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2ychkv | other than customization, what exactly does android excel in over iphone and ios? | Please be as non-biased as possible. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2ychkv/eli5_other_than_customization_what_exactly_does/ | {
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"I would say the key things are android's integration with google software, although Apple recently developed their own cloud and whatnot google still has better maps, docs, etc.\n\nAnother thing is memory, you have to pay a lot more for a 64 gig iphone and there is no expandable storage.\n\nThen there's the removable battery and the use of widgets.\n\nCustomization encompasses both the software and the choice of phone. Apple has just the iphone.\n",
"First of all, Android is a [phone] operating system software, just as iOS is the operating system software for iPhones. The iPhone series is the Apple phone hardware designed exclusively to run iOS. \n\nSo the keyword here is **exclusive**. Meaning Android is more or less designed to run on a variety of different types of hardware. Which is why there are tons of hardware manufacturers who design phones that support Android, but only Apple designs phones that support iOS. This also helps to explain the customization argument. On the software side, there is a larger market space for Android applications since there is a greater number of Android-based phones used by consumers. Though the argument stands that because iPhones are so prevalent, that the market for iOS applications is still substantial.\n\nBut the difference is two-fold. Because Android is used by all different phones, technical support from Google is often nonexistent. Because iOS is supported only on iPhones, Apple can easily provide technical support for both the hardware and software issues.\n\nTLDR; Android is open-source software, while iOS is not.\n[fine print: Android is not entirely \"open-source\" by its traditional definition]",
"Price. A high end android phone costs a fraction if the latest iPhone. Compare a onePlus One to the latest iPhone in both specs and off-contract price.",
"I'd say one of the advantages of Android is that you're not bound to the things Google gives you. If for example you want an app that's not in the Google play store, you can download the .apk (app installation) file manually, or you can download a different app store. \n\nThere's just more room to do what you want, which goes beyond customization in my opinion.\n\n",
"One of the biggest advantages is hardware choices. If you want an iPhone until recently you had one screen size to choose from, and now you've still only got two. With an Android phone there are countless screen sizes to choose from. It goes on from there, replaceable batteries, expandable storage, FM radios included etc... The differentiation in hardware is really what sets it apart. To some this is a big advantage. ",
"There is no such thing as a non-biased opinion on this topic around here. \n\nThere are annoying Apple fanboys and annoying android fanboys and they will both invade this thread shortly. ",
"Its kinda hard to compare the two. Apple's control over the hardware and software has yielded better performance and stability in contrast to Google who has focused their last few updates on improving performance (Project Butter, Project Volta, etc.) with mixed results. Google's insistence on fighting Microsoft's low end Lumias has weakened the Android brand because the inherent nature of not being able to control software on hardware with lower specs (MS has tried to strike a balance between the oppressive software control of Apple and the free range hardware of Google, allowing it to standardize low end specs and offer better performance).\n\nThere are a few design philosophies that Android follows that really resonate with its customization that is more than just a homescreen widget. So much that Apple has begun to follow it with iOS8. That big thing is called *Intents*.\n\nAndroid's Intents system is very basic, but very powerful. It's a way for the OS to reassign user-facing responsibilities to third party apps, even if they take the place of a bundled system app. For example, say I hit an app that has a contact name in it and I hit the UI indicators to send an SMS. Instead of the system calling out for ~~iMessage~~ or something it sends a blank call to the set default SMS app, which I can reassign to my choosing. I can do this with calendar events, invites, I can do this with email, social sharing, media storage, music players, browsers, file pickers, photo viewers, cameras, home screens, etc. All system defaults in Android are interchangeable (very much like the desktop Windows). The Intents system is customization to the biggest level ever seen on a phone operating system. This is where Android draws its strength. Don't like the camera app? Swap it, and because the OS is so modular, there won't be any seams showing system-wise (UI/UX is inconsistent, though), your button shortcuts, Instagram photos, etc. will all work.\n\nIts pretty cool.\n\nOff topic: I've been with Android since the very beginning (contributing bug reports on the first releases of CyanogenMod on my G1) and I think I'm gonna head on over to iPhone 6S. The Android flagships are intense, but the inconsistencies in UI and UX are irritating (not to mention that Google itself can't even follow its own UI design guidelines). My dream phone would honestly be a Windows Phone, but the number of basic apps missing and going abandoned is staggering.",
"One thing that many people forget to mention is the ability for apps to interact with each other. In iOS, every app is sandboxed, which basically means that one app can only change things within itself. On Android, the user is able to click a \"share\" button and open up other applications directly from the other app. This makes the OS experience very modular and preferable, especially when you don't like the default applications on your device.",
"Motherfucking Swype texting. Idk if all Android phones have it but I can't imagine typing on a phone without it, it's so convenient and quick compared to typing on an iPhone, and from what I can tell iPhone's autocorrect will fuck you over more often than Swype will",
"Having both an android tablet and an ipad I like the battery life of the ipad, for everything else I prefer the android. Google integration, multi tasking, notifications, scrolling and general responsiveness and especially the keyboard all just seem to work better for me on my android devices.\n\nMaybe the newer iphone/ipads have better glass, but the glass on my ipad is a fucking joke. Three days of light usage caused a scratch. Two years of treating my android phones and tablet like shit, not a single scratch.\n\nI like the ipad, I probably wouldn't buy one again.",
"Google Now is more functional than Siri in most regards. Google Now has the benefit of being backed up by Google's search engine and offers more usable voice commands. Some android devices have \"always listening\" functionality so you can use voice commands with out even having to turn your phone on.\n\nVariety of hardware. Until pretty recently, iPhones didn't have a larger screen size option where as Android phones came in all shapes and sizes. Android device makers are also free to include the hardware features and functions that they want. For example, Samsung has included Wacom Digitizers and styluses on their Note series devices, Motorola has included lower power CPUs that control several functions of the phone while the screen is powered off for always listening audio and other functions, etc. Some phones have removable batteries and SD cards, other phones go for non-removable battery so that they can be made slimmer. Basically, you can choice from a wide variety of devices based on what features you want.\n\nAnd I know you said \"other than customization\" but customization is a huge part of it. practically every app that comes on an Android phone can be replaced with a different one from the Play Store. You can decide to use Firefox as your default browser instead of Chrome. Android is designed to do this seamlessly so that if you never want to use the original app, you never have too. You can really use your device how ever you want to and it doesn't feel like you have to fight your device to do it. I once heard this summed up as \"iPhones just work... but they only work one way. If you want to do something different than the way that Apple wanted you to do it, you are out of luck\"\n\nDon't get me wrong, there are plenty of things that I can say bad about Android in general, but I personally prefer it to iOS because I feel like I get the experience I want out of my device instead of the experience that someone else wanted.",
"It's hard to give you a great answer without pointing to customisation because it's a huge part of it that really encompasses quite a few areas. However, I'll be a bit lame and cop out and say... \"Openness\". Yes, I know it's pretty much the same thing!\n\n Don't want to use a manufacturer's desktop software? Fine, just use the file system. Want to have the latest software feature that's available on another device? Chances are there'll be an app for that. Customisation isn't just \"you can change your keyboard\" either btw. You can completely theme your phone with your own custom widgets, layouts etc (awesome site is _URL_0_). You can even change your lock screen. Also, because it's open it means it's not locked in to one thing as much. Airplay is great on iOS but I love how my Android device can talk to Airplay devices but also DLNA and pretty much any other wireless standard.\n\nHowever, to answer your question as closely as it was asked... For me, it's that Android can be much closer to a PC, if you want it to be. You can download, open, edit, share files easily. Torrent. Use USB attachments (memory sticks, mice, keyboards, even other phones!) and much more that I'm probably forgetting.\n\nIf you're trying to decide whether to go for Android or iOS... It's really a matter of do you prefer a locked in system where everything works, talks to each other and pretty much always plays by the rules or would you prefer something open and completely customisable? They really are opposite ends of the philosophical spectrum (with Windows Phone being in the middle). It used to be the case that you got a really clunky experience with Android but you got all the awesomeness that came with it. It's really not the case any more, Android has definitely caught up iOS in that regard. There's a good reason that iOS 8 (and 7 really) added a bunch of Android features. It says a lot. They're both great and I do love iOS but... I wouldn't go back to it. I don't think I could. Android is just fantastic. \n\nSource: I work with phones in a technical aspect and have done since before smartphones were a thing. \nEdit: I've had the iPhone 2G, 3G, 3Gs, 4, 4s then had Galaxy S3, Note 2, S4, Note 3, LG G2, Nexus 4, HTC one M7 and currently using a Nexus 6. So had a lot of personal experience with it too haha.",
"You don't need itunes.",
"To me, Android is better standard-wise. Full bluetooth compliance, usb port that lets you to use any charger of any other phone or brand, ability to use the phone as a usb drive (I use this a lot).\nAlso, an alternative app store like F-Droid is a great plus. I'm currently using more open-source apps downloaded from F-Droid than Google Play.\n",
"Variety and consumer choice in hardware manufacturers?",
"My main thing is it's more like a pocket PC. I can have an emulator for everything up to a PSP, have my Ps4 controller plugged in to it and play any classic game. I also like being able to do things like extract files and explore the storage just like on a PC. There's also the fact that you can't change much about how your iPhone works, but on Android you can have a different app than stock for everything. Up until recently you couldn't even change the iOS keyboard."
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9bjtpe | american football conferences and league system | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/9bjtpe/eli5_american_football_conferences_and_league/ | {
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"I'm assuming you're talking about the National Football League and not college football or any other leagues.\n\nThe NFL used to be an 8-team league before eventually merging with the AFL in 1969. When it did this, it broke the existing teams into the AFC and NFC, which persist to this day. Both have different divisions. Various teams and new divisions have been added since them.\n\nBoth the AFC and NFC currently consist of 4 4-team divisions named the AFC/NFC North, South, East, and West corresponding (roughly) to the team's location in the country. In a 16-game regular season, each team will play 2 games against each of its 3 division rivals, and 4 games against the opposing conference. The remaining 6 games are teams from different teams in their own conference, but different divisions.\n\nThe team with the best record in each division automatically goes to the postseason, with the 4 next-best teams from any division making the \"wild card\" round (An extra round only the wild card teams need to play) of the playoffs. This is meant to bring up the quality of the postseason. Imagine you had a 16-0 team and a 14-2 team in the same division and the 14-2 team didn't make the postseason! Especially if a weak division is sending a team to the playoffs. Twice in NFL history, a team that has had a losing record has made the playoffs, because they still had the best record in their division.\n\n[Here's a graphical representation of the conferences and divisions](_URL_0_)\n\nEdit: Added additional details, graphic."
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140a5i | - how can the famous (eg lindsay lohan) continuously be in the headlines for being arrested on different occasions without progressively severe punishments? is the process of law in any way handled differently for people based on fame or wealth? | If the answer is simply corruption at work, that's fine. But it seems there is a consistency of celebrities who get in strings of trouble and just...bounce back. Is there any specific reason why? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/140a5i/eli5_how_can_the_famous_eg_lindsay_lohan/ | {
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"I have a friend that has been arrested over 70 times for public drunkeness and/or open container. He is not rich and/or famous. ",
"LA County's prisons are severely crowded, so unless you commit something a lot more serious than cocaine or shoplifting the chances are you won't be in jail for too long. (Also, Paris Hilton spent time in jail.)",
"Working in background screening for a living, it's extremely common to see people with extremely high numbers of convictions and no progressive punishment. \n\nHell, I've seen people have a dozen probation violations on felony cases and the only punishment in each instance was to continue with probation. \n\nI don't think celebrities are too special in this regard, honestly. "
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bzxily | how can a half-built house be left in the weather with no issues? i’m talking about a wood frame with plastic in the rain type of thing. | Edit: this really blew up but i can’t read 200 essays about wood treatments so thank you to everyone who contributed ❤️ | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/bzxily/eli5_how_can_a_halfbuilt_house_be_left_in_the/ | {
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"Construction materials are typically rated to a certain amount of exposure to the elements to allow for construction time. Thats why construction scheduling is so important, so that sensitive things arent ruined before the building is up. Ive seen thousands of dollars worth of material discarded because it sat too long in a building that wasnt sealed\n\nWood framing can go quite awhile exposed before there starts to be a real concern. But it depends on climate and whatnot. \n\nSource: work in architecture",
"That plastic (usually tyvek or zip) also adds a lot of weather protection. That's why it's there, to be an additional barrier for the wood should any moisture get under the siding hat will be put over it. I would also guess that if a frame were left bare in the rain they wouldn't add the side panels until the sun has dried it out. If you added the sides with a big puddle sitting on the foundation, it would be trapped in there.",
"All building materials arrive on site with a specific moisture content. They can get wet until the building is ‘dried in’. Once the building is dried in, you have to wait for the moisture content in the framing to return to the proper level before sealing everything up with drywall and insulation from the inside. Framing getting wet isn’t a problem, it only becomes a problem if you seal that moisture in before it has had a chance to return to proper levels.",
"(In southern Ontario) a framed house is fine for a while in the rain for a few reasons. \n\n1) That plastic wrap shit, usually Tyvek, is hydrophobic\n\n2) we try to get shingles on quickly to minimize how wet it gets, especially the horizontal surfaces because puddles can form and that's the real issue. \n\n3) wood only warps when wet if you make it. If it's laying perfectly flat, it will dry flat. To a certain extent, the framing of the house is fixed in place, there isn't any major warping that can really happen. Plus, it shouldn't be sitting exposed for too long in the first place.\n\n4) going back to #2 for a moment, puddles are an issue because they are constant. That wood is soaking indefinately that's when it starts degrading the wood, mould, etc. Wood getting wet and drying isn't a huge deal aside from the threat of warping.",
"The most sensitive things in a building regarding moisture is the insulation and the electrical work. Typically the order of operations allows a roof to be installed and at least an air barrier (plywood with tyvek building paper) barrier before insulation and electrical is done. If enough moisture is allowed to let the framing materials to get wet than many contractors will use fans and heaters before the drywall stage, but after roofing and siding, to correct the house to the proper humidity and moisture content.\n\n\nMost plywood has an amount of time lt can be exposed before it degrades, and lumber can be dried. We always try to wrap our buildings before we let the plywood sit exposed.\n\nOnce it's to \"lockup\" with doors and windows in, and roofing and siding on...the finish material can be safely installed.\n\n50% of what we do is weather proofing for our buildings, when you see framing up in the rain, that's half way done.\n\nI'm a carpenter.",
"Ex carpenter here. It’s not the rain that matters in rough framing. As long as things have time to dry it’s fine. Generally right after the rough in the roof gets done so no more direct water comes from above. \n\nYou might be surprised but its sun exposure that does a number on wall studs. Generally the lumber can still be a bit too wet when delivered so it isn’t finished moving. You can get some nasty bows after a few days of baking. But that’s what the back out crew is for. They go through and rip out or straighten bad studs before drywall.",
"don’t renegade mormons, like colorado city, never finish their houses so they don’t have to pay property tax?",
"Back in 2008 when the housing market went and fucked off, there were some unbuilt homes near me. It was just the basements. They remained exposed for almost 3 years. There was no rebuilding the basements or anything. How'd they manage that? Wouldnt there be damage overtime?",
"And that’s how you end up with “sick house syndrome” when they come in and wrap a house whose framing was exposed to a season of rain. They have no way to breathe.",
"Any wood in direct contact with cement must be treated since concrete always has some level of humidity. All the other wood sheds water rather well. Also all the 2x4 or 2x6 and such are in a place that is exposed to air and can dry quickly. The only thing that is a problem is OSB plywood. On a vertical wall it still sheds pretty well but when we do a roof the goal is to cover it the same day because it can't shed as well and it will definitely swell and make it impossible to fit the spacer clips on. Also the last thing you want compromised in any way is the roof that will see plenty of abuse over the years.",
"It's not always the case that there are \"no issues\". The IBC strengthened the inspection requirements once the reasons behind the Berkley balcony collapse came to light. _URL_0_",
"I’m a home builder here in Portland Oregon where it rains half the year. We build all year round. We frame it and don’t care if it gets wet. Then once the roof is on I bring in specialty crews who use moisture meters and see where the water is accumulated. We use fans, heaters and dehumidifiers to suck all the water out of the wood framing to the appropriate moisture content and then they certify it. \n\nIt needs to stay wet awhile for molds and such to start growing. We pull the water out way before that happens. \n\nIn fact we do this even in the summer sometimes if we don’t use kiln dried wood and we do get water out. That’s because the framing lumber comes to us green and “pond cured” as we call it where it’s basically been floating in water till recently and is still real heavy.",
"I use to help frame houses and once you nail the boards into place they resist warping well in the rain for a while. I threw away so many boards that were left out when someone didn't cover the boards back up with a tarp when leaving on a Friday. Also normally the day after it rains you spend a lot of time cleaning up water. Normally you can push broom rainwater off somewhere, but sometimes you may even need a squeegee. Also the wind will blow stuff over a lot. Once the roof is on water will mostly be diverted from going anywhere important. They wrap the houses in plastic and shingle the roofs to give time for everything else. Then they come back later and put decorative stuff like brick, rock, stucko, siding etc.",
"Basically i see 3 issues. \n\n1. Rain will fuck up isolation materials like rockwool or the likes(styrofoam is a non issue). It takes ages to dry out and will make it lump together and be bad in general. So it cant be in direct rain for any period really. Wood can last a long time, even untreated, but mostly you use some chemicals to keep wood from rotting away. Especially the wood that is meant to be outside(outer wall) is chemically treated. Wood skeleton will not be exposed and doesnt need protection other then ventilation and a outer wall.\n2. Sunlight is a factor but its a slow process for it to become problematic. Mostly in regard to plastics this could become an issue.\n3. Wind can knock shit down and blow out the plastic barrier(very bad).\n\nSo in regards to seeing some wooden house with a roof and no real outer wall just maybe some sheet of fabric(dont know the english term) the house can stand like that for a long time no issues. It will get damp and have moist problems but it could still stand for a long time.",
"Additionally, a frame of a house does better in wind because theres less surface area the wind is hitting. So the surface area the wind is hitting is now only the beams, so relative to their strength it's nothing.",
"Wood comes from trees and trees live wet. Wood can easily dry up to a certain extent, as long as the wood isn’t out for months on end you can dry it. This is also why after a water loss you should try to dry out wood flooring instead of replacing, they can take some moisture and dry it out before being damaged",
"There are impacts, and anyone who has bought a brand new house knows them. Over the first 12 to 24 months of new home ownership, wood framing loses a great deal of its moisture content and something called settling occurs as the wood dries unevenly. This results, usually, in nail pops, doors being out of square, and small cracks along drywall seams. Most new home builders offer an inspection and free fix at that one year point, where they come in and fix all the nail pops, calk all the exposed drywall seems, repaint, and adjust any doors that are out of square.",
"Simply enough, water doesn’t produce mold. Water in a sealed environment does. The wood can get wet as long it can also breathe. \n\nThat being said, I’m a young builder and I originally had a huge issue with this. I now understand that it is ok to do but ultimately, I’d try and avoid it as much as possible. Not to mention, much of today’s material has built in waterproof membranes, making it even easier to avoid.\n\nEdit: Just realized what sub this was. \nHey 5 year old, go smell your sponge by the sink. Does it stink? If not, it was properly wrung out before left to sat. Now earn some chore money, wash some dishes with this perfectly clean sponge and leave it soaking wet this time. If you come back to it in a couple hours, it’s gonna be pretty stinky. The stink is mold. Now unlike the sponge, the mid-construction house that got wet is also open to the sun, which will dry it out. Much like wringing out the sponge originally would achieve. Mold has a much harder time growing in an area with no moisture.",
"\"with plastic\"\n\nDoes this mean the housewrap you see on buildings. If that's the case housewrap is a weather-resistant barrier to protect the wall assembly from the rain and it allows water vapor to pass to the exterior.",
" An **ounce of prevention is worth a pound of cure**. \n\nThey should be tarping it over and preventing it from getting wet to begin with.... otherwise it is just a headache. There is no reason a normal 2000 sq ft house should not be dried in, in a couple days and or tarped over if it rains. Even moreso the tarps for larger houses, it can take weeks to really dry out... \n\nAnything else and your contractor is taking shortcuts.",
"Back when I was working construction (coastal NC) it was common for projects to come to a halt for one reason or another, usually lack of money. Given that this was the big building boom of the 70s, we'd just move on to the next house, leaving the unfinished house to \"weather in\" as we called it. You'd run into a pal at a bar and he'd say \"Didja finish that house in Oyster Pointe?\"\n\n\"Naw, we're letting it weather in.\" \n\nSimilar to \"doing road work\" after being sentenced to pick up trash for community service.",
"All dimensional lumber can get wet for the duration of the build and cause no problems due to minor treatment. I'm a contractor was a carpenter, the truth is after your framing and sheathing, you tyvek and do the roof, no inspector does a moisture test on a building, not where I've worked anyway. By time you're done with the exterior the interior is still exposed and will be dry by time you start finish work. Mold in a house is commonly caused by leaking windows and showers, not from pre existing moisture.",
"Maybe someone here can answer my question then. How is that I can buy perfectly straight lumber at Home Depot or Lowe’s but when I take it home, the next day even though it was laying flat, it’s now warped like crazy!? How does this happen and why does this not happen to the frames of houses?",
"Generally speaking, it’s not that bad for most building structures (especially ones made from wood) to get wet. It’s much worse if the structure can’t properly dry out because the moisture is trapped under insulation. So as long as the structure can dry out properly, it’s mostly fine.",
"Tarps and plastic to reduce direct exposure, then we would do a “dry-out” before we put the interior boards in. Then we would use whatever was needed, depending on weather, to return the moisture to proper levels. We also liked to build in the late spring through summer because that helps things dry out, but that is a regional climate thing and not applicable everywhere. Once you get the roof and the siding lined, the vinyl siding, the windows set in, etc. we might use industrial fans to air everything out just to be sure, before flooring and drywall went up.\n\nOur priority was usually the roof, and we also would convert a room into a “safe room” for equipment, which we boarded up at night with all our tools and machinery so people couldn’t walk in and grab anything/steal from the site"
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7wf8d8 | why do vehicles that have diesel engines cover their front grills in the winter? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/7wf8d8/eli5_why_do_vehicles_that_have_diesel_engines/ | {
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"Diesel engines are very temperature sensitive; diesel fuel gets too thick to run an engine if it gets too cold.\n\nAs an engine runs, it gets warm, which helps the diesel fuel. However, if it's warm outside, you don't want the engine to overheat, so you want a lot of air blowing over the engine and radiator to balance it out.\n\nIf it's cold outside, and you're driving down the road, that's a lot of cold air blowing on the engine, so it's harder for the engine to stay warm, so covering up the front allows the engine to run hotter, which is better , but the ambient air is too cold for the engine to really overheat.\n\nHere in North Dakota with super cold winters, we even cover up the fronts on gasoline engines, because the interior heat comes off the engine and it can be hard to warm up the inside of the car if you're driving fast in below-zero weather.",
"diesel fuel is actually oil. The colder it is the thicker it gets....the grill is meant to cool off the motor (with the fan and radiators) so its counterproductive in the winter therefore you need to block the grill to help keep the heat in the engine bay....\n\nnew trucks (like mine) have a fuel heater, but that is only good when the truck is actually warm and running....most diesels also have a plug in front which you can plug into which is connected to an engine heater when you are parked overnight...mine keeps the engine block heated to 70*F...but I still need to put additives in the fuel to stop it from turning to gel in the tank and stop it from turning to wax (which is a by-product that will clog the fuel filters)."
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32yzsr | what does adderoll do in your brain to help you focus so much? | So, theoretically, say i get some adderoll from a friend to help me study for a college exam. What does the adderoll do in your brain to help you focus on a task for hours and not look at your phone or any other distractions? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/32yzsr/eli5what_does_adderoll_do_in_your_brain_to_help/ | {
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"all the parts of your brain are connected by 'wires' and your toughts are like electricity (neurons), now what adderal does is make the wires bigger so more neurons can pass thru. making it so that you can prioritise and process your toughts easy(er). \nsource : user"
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g0mwjl | why can’t containers be recycled if they have even a little bit of food on them? how does a tiny bit of dried yogurt on a yogurt cup impede the recycling process? thanks! | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/g0mwjl/eli5_why_cant_containers_be_recycled_if_they_have/ | {
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"I saved this post because I never thought I wanted to know this and now I'm waiting for the answer",
"I've not heard that any plastic recyclables have to be pristine in order for them to be recycled. And I think that's not the case.\n\n[This source](_URL_0_) confirms that \"a quick rinse is fine--there's no need to make it clean enough to eat off of. The heat process \\[in the recycling\\] can burn off small amounts of stuck-on food.\"\n\nBut the source also notes that, in \"single-stream\" communities (where you put all your recycling into one bin rather than separating them), small food particles, oil, or grease could ruin paper recyclables if they're mixed in.\n\n[A confirming source.](_URL_2_) This source, a TV news report quoting an official who works at a recycling center, notes that the rinse is for \"the benefit of the people who have to touch\" the soon-to-be-recycled materials.\n\n[This source](_URL_1_) takes a slightly more pro-washing perspective --lots of food waste will increase the risk of rats and may take so much work at the recycling center that they employees will throw it out rather than invest the time (and money) to clean it sufficiently to recycle (apparently especially glass). But even it recognizes that they can be \"a little\" dirty and pizza boxes can be \"slightly greasy.\"\n\n & #x200B;\n\ntd;dr -- Question has a false premise. Unless your local recycling plant says otherwise, \"little bits\" of food are absolutely fine. Particularly greasy things, particularly sticky things should get a little more of a rinse.",
"You are right in the sense that different amounts and kinds of food would have different impacts on the ability to recycle some material.\n\nHowever, the second you start looking at it like that, then you have to implement measures that analyze each piece of recycled material to see if it meets those standards. The more rules you have, and the more specific and granular they are, the hard and more costlier they are to implement.\n\nRecycling is about dealing in bulk. That is, processing the largest quantity of material in the quickest amount of time for the lowest cost. Things that make the process more costly or take longer risk making recycling not a worthwhile process which results in less recycling altogether.",
"basically that is because some countries do not want to import waste, and hence impose very stringent \"purity standards\" \n\n_URL_0_\n\n_URL_1_\n\n > For decades, we were sending the bulk of our recycling to China—tons and tons of it, sent over on ships to be made into goods such as shoes and bags and new plastic products. But last year, the country restricted imports of certain recyclables, including mixed paper—magazines, office paper, junk mail—and most plastics.\n\n > About 25 percent of what ends up in the blue bins is contaminated, according to the National Waste & Recycling Association. For decades, we’ve been throwing just about whatever we wanted—wire hangers and pizza boxes and ketchup bottles and yogurt containers—into the bin and sending it to China, where low-paid workers sorted through it and cleaned it up. That’s no longer an option. And in the United States, at least, it rarely makes sense to employ people to sort through our recycling so that it can be made into new material, because virgin plastics and paper are still cheaper in comparison.\n\n_URL_2_"
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8lzqu3 | what is the difference between distilled water and regular water? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/8lzqu3/eli5_what_is_the_difference_between_distilled/ | {
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"Distilled water should be H2O.\nRegular water has other things in it. For example NaCl, Ca, ...",
"Distilled water is simply water that has had all minerals or additives etc. filtered out of it. Pure H2O\n\nSome people say it's bad to drink distilled water since you need those minerals but as long as it's not all you drink you're fine.",
"Regular water is a mixture of water(H2O) and small amounts of other compounds like Common Salt(NaCl), Calcium(Ca), etc. \n\nDistilled water is just water(H2O). \n\nRegular water can conduct electricity but distilled water can not."
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1mcnyw | why don't companies who produce porn try to get free sites like pornhub shut down, when if the same sort of service existed for non pornographic movies and films it'd likely shut down? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1mcnyw/eli5_why_dont_companies_who_produce_porn_try_to/ | {
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"Because the first hit is always free. Free porn is advertising for paid porn sites."
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1r3fh2 | can anyone explain what dr. who is about in less than 500 words? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1r3fh2/eli5_can_anyone_explain_what_dr_who_is_about_in/ | {
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"An alien called The Doctor with the ability to come back to life (regenerate) when he dies travels across both space and time with human companions in a Tardis, which is basically a combination space ship and time machine. The show is about their experiences, which often include saving humanity.",
"It is about a man called The Doctor. He is an alien (known as a Time Lord) from the planet Gallifrey. He travels around in a time machine disguised as a 1950's-style London police box (known as the TARDIS) and fights evil and promotes peace and understanding. \n\nThe Time Lords carry the power of regeneration, where upon death they will take on a new form and continue with life. The current Doctor is considered the 11th such incarnation (though this number is not entirely accurate). \n\nThe Doctor is sort of a rogue amongst Time Lord society, in that he travels the universe and interferes with the lives of lesser species (such as humans). He has developed an attachment to Earth and its inhabitants, and regularly travels with a human companion (the current one is Clara Oswin Oswald). \n\nThe current major story arc details the Doctor's involvement in a conflict known as The Last Great Time War, wherein the Time Lords and their greatest enemies, the Daleks (a robot species dedicated to exterminating all life other than Dalek-kind) were mutually destroyed. It is accepted that the Doctor was the cause of this event, which the 50th anniversary special is due to explore. ",
"There is this guy, who goes by the chosen name of The Doctor. He belongs to a species that mastered time. And so he has a time machine (called the TARDIS) which is also a space ship that travels as the speed of plot. Basically he can go anywhere or anywhen within a few minutes.\n\nHe travels the universe doing good. And he is usually accompanied by one or more companions (usually humans) who are along for the ride.\n\nThe original show was a kids show. One week they would travel back in time and learn history. The next week they would travel forward in time and learn science. But over time that became less important and it became a sci-fi adventure show.\n\nOne brilliant bit was that they decided The Doctor could regenerate from near fatal wounds. But when he did his body would look different and different parts of his personality would show up. This lets them replace the lead and the writers without too much worry about continuity.",
"It's a british Sci-Fi series that's been running since the 60s. It stars The Doctor, an alien from a powerful race called the Time Lords. The Doctor can regenerate his body when he is close to death, and has done so many times before (This is a great way to change actors when they can't or won't do the role anymore). \n\nHe travels in an extremely powerful time machine called the TARDIS. The TARDIS adapts to camouflage itself with whatever time period its in, but the Doctor's TARDIS is a little broken and so it always appears as a blue police box.\n\nSo the Doctor travels around time and space and gets into adventures. One day he might go back to Pompeii the day the volcano explodes. Another day he might visit the year the Earth finally naturally ends. Another he might go off to some strange alien world. He usually has at least one companion to travel with (usually human). He's a big believer in peace and non-violence; though those philosophies are often scarified to save the day. His personality also slightly changes with each regeneration. \n\nHe has a device called the Sonic Screwdriver, which basically does whatever the writers want it to do. It unlocks doors, can be used as a shield, analyses things, etc.\n\nHe has many different nemesis such as the Daleks, Cybermen and The Master (another Time Lord). \n\nIt's a fun, whimsical soft sci-fi series with a lot of adventure. If you want to start watching, I'd start with the 2005 series, first episode is called \"Rose\". It's on Netflix. \n\nThe series was canned in the 90s, but started back up again in 2005 with a whole new cast and writers. It continues the original story, but was designed as a good starting point for people to start watching. Another good starting point is the episode at the beginning of season 5: \"The Eleventh Hour\". At that point the writing staff and actors changed and the show takes on a different tone. But I'd start with \"Rose\", I like seasons 1-4 more than 5-7."
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1sqy9z | how do they connect water/sewage pipes for houses or buildings in both built up areas such as cities and isolated areas in the countryside? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1sqy9z/eli5_how_do_they_connect_watersewage_pipes_for/ | {
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"Depending on how far out in the countryside, houses may be on their own wells and use septic tanks (basically private sewage treatment). "
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5m7bj0 | how does match fixing work? | Who are the people behind it? What does each party get out of it and why do professional athletes agree to such a risky act? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5m7bj0/eli5_how_does_match_fixing_work/ | {
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"Here's one example how it may work:\n\nMr ABC is a person who bets on games. \n\nMr XYZ is an athlete who's the MVP for his team. His performance is gonna determine whether they win or lose. \n\nThe betting odds expect XYZ's team to win since he's in amazing form.\n\nABC sees a great opportunity here. He pays XYZ a big sum to underperform and throw away the game. He bets a huge sum on the other team. The other team wins and ABC makes alot of money.\n\nWhy athletes agree to it is a much more complex thing. Many factors can cause that. It's not possible to generalise a reason for that. Maybe they want money, maybe they're being coerced, maybe they're being fooled under some pretense.",
"Keep in mind the athlete doesn't actually have to lose to fix the match. If the underdog has a certain point spread, a gambler can pay a player on the favorite to keep the game within the point spread (\"Point shaving\") so that bets on the underdog win even if the favorite actually wins the game outright.",
"Pittsburgh is playing Miami this weekend, and spread is -10. This means if you bet on Pittsburgh, they have to win by 10 for you to get your money. There is roughly a 50-50 chance of this and it is an even money bet, so there is no good way to get an edge, betting is simply a matter of luck.\n\nBut there is a bad way to get an edge. If you can convince one of their key players to make sure they lose by more than ten points. Since they are a big underdog, they are expected to lose anyway, so losing by a little more would not seem too suspect. That way you can bet a lot of money on Pittsburgh and be sure of winning, or at least know your chances are better than they should be.\n\nWhy would a player do this? Maybe the have gambling debts, a sex tape they don't want to get out, or someone has evidence they are using PEDs. Or maybe they are just disgruntled and greedy. ",
"first off, you have to understand there are several types of match fixing. Most types revolve around a binary result (win/loss, yes/no) because that means fewer variables. \n\nMost of the time, the people getting something out of it are gamblers (who bet on the pre-destined result) and participants (who are paid to help create that result). \n\nThe huge majority of match fixing occurs in events that are fairly low profile; the reasons for this are fairly obvious. Fewer people paying attention, and a lower 'cost of entry' (it doesn't cost as much to convicne people to collude).\n\nI'll try to give a few examples. \n\nThe easiest: win/lose results involving only two competitors. This is thought to have happened fairly recently in Tennis, and Snooker. In the early rounds of a tournement - especially 'tour' events - the money for winning an early round is really not much. So a betting syndicate might decide to offer one of the players some money to essentially \"take a dive\". To lose the game. If enough people bet on the other guy to win, the bettors can turn a profit even once the payment to the loser is taken into account. \n\nRelated to that - score betting. This is something that is alleged to have happened in sports like tennis; you'll get better odds for a player losing 6-2, 6-2 than just losing in straight sets. This is a bit riskier for both the player and the gamblers, because it assumes that one player has that type of control over the match. It occurs to me that for this to really work, you'd have to have both players in your pocket.\n\nProp bets: a few years ago, bookmakers (especially in England) started taking bets on some 'fun' in game events, like which team would get the first throw-in in a football/soccer game (things that don't affect the final score, but are easily verifiable). It wouldn't take much to convinced a player (probably the guy involved in kick-off) to 'attempt' a long pass to the wing only to 'overhit' it and see it sail out for a free kick \n\nMatch fixing the result of individual soccer games is not easy. It's a team sport, so either you have to have everybody on one team involved, or the referees, or both. The **Calciopoli** scandal in Italy in 2006 revolved around certain teams making arrangements to have 'friendly' referees officiate their games. In the 60s in England there was a scandal that involved several players getting involved to rig specific matches. \n\nCricket has also had its share as well (Hanse Cronje) and so does baseball (with the Black Sox of 1919 world series). In pretty much every case, the reason is for financial gain and that is usually from gambling. \n\nIt's actually become a lot easier to notice fixing with the advent of betfair and other betting exchanges. Experience will tell you the weight of money likely to be placed on a given match, so if more than is expected is wagered, that counts as the \"unusual betting pattern\" that you see mentioned in the news. Bookmakers are obviously very keen not to get caught in things like this as well, which is why there are such strict rules for staff to follow. \n\nSource: used to be betting office manager in the UK."
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puhmv | how close are we to war with iran? | Like i see the media every day and it seems as though tensions are getting worse but could we like....in the next 5 years? Will this be our next iraq war?
Now I'm not actually politically illiterate its just my expertise is way more domestic than foreign policy. When it comes to a lot of foreign issues it's mainly over my head. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/puhmv/eli5_how_close_are_we_to_war_with_iran/ | {
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"We are as close to war with Iran as the collective conscious of the country will allow. Right now a lot of media is really pushing Iran in a negative light, specifically with the nuclear energy (or rumored weapons) program.\n\nTensions are high because of the fear of a new nuclear equipped nation joining the international community are always feared, specifically when that nation doesn't play well with the NATO nations.\n\nThe issue is rather complex...Iran found a U.S. spy drone in it's airspace...which is pretty shady, if the U.S. downed a Cuban spy place over Flordia you bet your ass the U.S. would retaliate. The U.S. says that the U.N. has found plans for ballistic weapons that Iran could put a nuclear warhead on, Iran says that this information was false and is being used in an attempt to legitimize anti-nuclear Iranian feeling in the international community. Israel is ready to fight anyone over the drop of a hat, the U.S. loves backing Israel.\n\nA lot of it comes down to how willing the United States and Iran are willing to work together. In my opinion war is what you do when a nation can no longer be talked to and rationalized with...when literally your only option left is to silence their international voice by killing them off. I don't think our relationship or Irans' willininess to communicate have reached that level. However, what you're dealing with is a very conflicting view of interest. Iran wants nuclear energy, the U.S. views nuclear energy as a hop-skip away from nuclear weapons -- and a potential power surge for that government. \n\nThe U.S. says stop doing anything with nuclear technology, period. Iran says we're our own country and can do what we want within our own borders. The U.N. says whoa guys calm down.\n\nWe arn't close to war but the news loves to talk about hot button issues and a nuclear armed country with a shoddy relationship with the United States is a pretty good story to cover. However, there is a selffufilling component to it, in that the more we talk about how dangerous Iran could be, the more we start to believe that Iran is already dangerous.\n\nThe key to avoiding war is to keep open communications and good relations with the nations involved. The closer we are to being on the same page on issues the better both countries will feel.",
"It depends on what you mean by war.\n\nIf you mean U.S. troops conducting a ground invasion to attempt to overthrow the Iranian government and then occupy the country, then war is extremely unlikely and bordering on inconceivable. This is because we just got out of a situation like that, in Iraq, and it really went very badly by anyone's estimation. Iran would be a much more difficult country to do that to than Iraq was (larger, more population, stronger govt) and it's hard to imagine any circumstances where the Obama administration, or even a Romney administration, would want to try something like this. The American people, even those who tend to be pro-war, got very sick of the quagmire that was Iraq and are disappointed by the end result (which is not really a functioning democracy.) So no one wants to spend another trillion dollars and thousands of lives trying to start a war like this.\n\nIf by war you mean we shoot some cruise missiles at them or bomb a few military/nuclear sites, then that's something that's more possible. If we did that though there almost certainly wouldn't be a formal declaration of war on Iran; even though that's what the constitution says you need our politicians have been letting Presidents order operations like this under their own authority for a long time now. Iran would probably retaliate to attack like this but in a limited way-- like attacking Israel or behaving more aggressively elsewhere in the Middle East.\n\nIf by war you mean Israel attacking Iran alone, but with American approval, then that is significantly more likely. If it were to happen it would happen by mid-summer, because after that air strikes won't be able to damage Iran's nuclear program. \n\nThe reasons this might happen are: **1)** Israel really doesn't want Iran to go nuclear. **2)** The current Israeli administration is right wing and pro-war. **3)** Israeli covert attempts to delay Iran like Stuxnet and assassinations have delayed program but not by much. \n\nThe reasons it might not happen are these: **1)** It would be very difficult for Israel to do this successfully, since Iran is at the far end of the range of their bombers and they would need to refuel several times in midair. Iran also has air defenses that would make this difficult, and a failed attack would be worst-case scenario for Israel. **2)** An Israeli strike might only delay Iran's program for a short time, and it wouldn't be worth the costs if they can only buy a 6 month delay. **3)** In many ways Israel is unprepared for retaliation from Iran. Hezbollah, an Iranian ally, has missiles that can hit Tel Aviv, and the Israeli civilian population isn't prepared for and doesn't want to deal with the risk of sustained bombing. **4)** Finally, it is in Israel's diplomatic interests for other countries, the U.S., Europe, and Iran itself, to believe that an attack is likely. This is because the U.S. and Europe are going to be more willing to impose harsh sanctions on Iran if they believe the option is a potentially dangerous Israeli attack. So Israel will be acting like they might attack even if they wouldn't actually, because this strengthens their hand diplomatically.\n\n**Sources:** [This article](_URL_1_) was a widely commented on recent piece that quoted top Israeli officials discussing the pros/cons of the attack. The author believes an Israeli strike is likely.\n\n[Here](_URL_0_) is a response to that article by a highly respected international relations professor explaining some of the reasons why Israel might not strike. ",
"I agree with \"Philosoreptar\". \n\nThough it isn't mentioned at all. The cost of a war with Iran would be crippling for the US in the same way the cost 2 wars of occupation was speculated to be economically crippling 9 years ago. \n\nAccording to what's know as \"Just war Theory\" A nation has the right to pre-emptive attack on another nation it feels is a threat. \n\nThe question is how much of a threat is Iran? ",
"A long time ago, countries got together and decided that hitting another country is against the rules, unless that country is just about to hit you. \n\nThey put this rule in something called the UN Charter. \n\nThey agreed that if a country needed to be punished, it would be for the UN to decide; not anyone else. \n\nSo, if the U.S. and Israel don't break the rules, we won't have a war. \n\nSome countries think Iran is doing some things that are against some other rules. Iran says it is not being treated fairly. \n\nWhat they should all do is get together and talk so that it can all be sorted out so lots of people don't get hurt.\n\n\n\n"
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"http://walt.foreignpolicy.com/posts/2012/01/30/Israel%27s_not_going_to_attack_Iran_yet",
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7kbnsh | how are aquatic animals moved to zoos? | [deleted] | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/7kbnsh/eli5_how_are_aquatic_animals_moved_to_zoos/ | {
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"Why isn't anyone answering this? Now I'm curious! "
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5c37l6 | do we have a mathematical representation of time? | (other than hours and minutes....) | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5c37l6/eli5_do_we_have_a_mathematical_representation_of/ | {
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"No, not concretely. We typically think of time as a space in which events are placed; and this became extremely convenient when we found out that time-components can be intermixed freely with space-components in special relativity's idea of \"Minkowski spacetime\", as a way to simplify the complicated math involved in electromagnetism. At around the same time we got Einstein's theory of general relativity which changes the idea only slightly (the way you measure space and time now varies across space and time), and quantum mechanics, which bolsters it (the wavefunction evolves in time in such-and-so way). But in any case our model of time is some sort of continuous axis which you measure in hours and minutes.\n\nHowever we *do* have the seeds of a different representation for spacetime itself which views it as derivative, in the form of an offbeat but powerful mathematics known as \"twistor theory.\" In twistor theory there is a more fundamental space known as CP^3 in which everything in the universe is happening; points in real spacetime need to be identified at best with lines in this new weird space. However there is a reason that you haven't heard of this theory before, which is that it has not become successfully simple enough to persuade tons of physicists to use it to model the universe. \n\nIn fact the only suggestion twistor theory has for us in trying to think differently to maybe better understand time, is to imagine that maybe the world is one big causal network of connections, one big graph of what's interacted. On this view everything fundamental is moving at one unambiguous speed, the speed of light, and so there is not very much meaning to how long it takes to get wherever it goes. Everything that appears to be moving slower is somewhat *metaphorical*, kind of like how you might say \"this is a waterfall.\" That works in a very practical sense and is very helpful as a category: but if you reason through it you must acknowledge that there is no *fixed thing* out in the universe which is a waterfall; the water molecules in the waterfall keep changing and you're more referring metaphorically to the causes and circumstances which occasion the falling of water in this place and time, than any concrete physical object. Similarly everything which appears to be moving slower is really some sort of mental model of some particles which are bouncing off each other and interacting a lot, and we are mentally grouping them together into something that \"moves slower\" than the speed of light.\n\nIn this view time is something more like \"the complexity of some network of interactions, compared to some reference complexity.\" The easiest way that this reference complexity might be understood would be to identify the Planck formula for energy, E = h f, with the rest formula for mass, E = m c^2 . Possibly the very thing that we mean with mass is some sort of reference complexity f = m c^2 / h to temporal interactions, and we judge time based on these relative complexities.\n\nBut, as said above, that's a bunch of philosophical BS at this time because the theory is not simple enough that everyone is phrasing physical models with it. "
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b62q0i | why can’t we change our usernames? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/b62q0i/eli5_why_cant_we_change_our_usernames/ | {
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"Imagine that everyone in class has a different coloured ball of yarn. As we go on through the year these yarns are going to magically tie a knot to each other whenever you talk to someone else in class. At the end of the year we can see everyone you talked to, and when! But if you wanted to change the colour you picked at the start of the year... Well... It'd be a mess. "
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4g9w57 | why do people use cheque cashing businesses instead of a bank? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4g9w57/eli5_why_do_people_use_cheque_cashing_businesses/ | {
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"I work for a bank and open checking accounts for a lot of people. i also decline to open checking accounts for a lot of people. some people just can't get a checking account and go to the bank to cash their checks because they've fucked up in the past and won't be allowed a second, third, fourth etc chance. with our online applications I routinely see people who have charged off $2,000+ in accounts with different banks. at that point nobody is going to give that person another chance because 99 times out of 100 it's just going to be a loss, and it's not worth it to let them have an account.\n",
"Could be any if a few reasons, maybe you're just impatient, or you need the money quickly or your bank account is overdrawn and you need cash more than you need to clear your overdraft. ",
"Some people do not have bank accounts or cannot easily get to a bank to deposit their check. A lot of check cashing businesses also offer high-interest loans for people who can't get them elsewhere.\n\nCheck cashing businesses tend to set up shop in economically poor areas.\n\nIf you can get to a bank, that is pretty much always a better idea.",
"Not everyone has a bank account, and many checking accounts are not free. Many have fees associated with them. ",
"If you are overdrawn any monies paid in to your bank account will be swallowed up by that, so if you cash the cheque at such a business you have money in your pocket..\n",
"Without the other answers being incorrect, it is also worth adding that illegal workers, foreigners etc. Often can't get cheque accounts. I've worked overseas before and been paid by cheque. What the fuck would I have done with an Italian cheque without and Italian bank account. Even if my home bank would cash it, they would charge a fortune.",
"In addition to the reasons listed above, some people are trying to hide money from garnishment (lawsuit or child support). Banks have a paper trail. Check cashing places don't.",
"Have worked in banking/finance for a while. Another big reason people use check cashing places is because they don't have a legitimate bank or credit union in their area. Sadly, most banks aren't willing to open a branch in a high risk area, so poor and rough neighborhoods are often forced into going elsewhere."
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6h4juu | what causes a lot of plants to grow back bushier after you prune them? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/6h4juu/eli5_what_causes_a_lot_of_plants_to_grow_back/ | {
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"I can only speak based on my knowledge of grape vines, but I'll give it a go. Basically plants have two \"modes\". They have a growing mode, and a mating mode. In the growing mode they will get larger, and put off more fruit, however a plant will eventually grow enough and switch to it's mating mode. Mating mode is when a plant stops growing and slows down fruit production to grow flowers so that insects can pollinate. If you prune back a plant properly, it will never leave it's growing mode, and will this keep getting bigger and producing more fruit.",
"I'm not a botany expert but I'll take a crack at this. I grow a certain type of plant and early in its life (seedling) there is a technique called \"topping\" in which the top growth tip of the main stem is cut off above a node. This breaks \"apical dominance\" , or tendency to grow one main \"branch/stem etc\", and cause the main stem to split into two at the node it was cut. \n\nThe way I would actually explain this to a five year old-\nThink of a plant in the forest. A deer comes by and bites off the top of the plant. The plant senses this and sends out hormones to other growth tips on the plant and will grow bushier. It's a defense mechanism. Or a response to stress. Something like that...\n\nAgain, I am no expert. But I do use a technique similar to pruning which makes my plants double in size. "
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1dq2z7 | why is it that i can have a clearly-formed sentence in a foreign language or accent in my head, but then have difficulty actually producing it? | A friend asked me what a particular accent sounded like. I wanted to demonstrate it. I could form a sentence in my head and "hear" it with a realistic accent, but when i tried to produce it, it sounded completely different. Why is that? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1dq2z7/eli5_why_is_it_that_i_can_have_a_clearlyformed/ | {
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"Because you don't know what you're supposed to do with your mouth and tongue to produce the sounds you can hear in your mind. ",
"also, people are much better at recognition than recreation.\n\nsay if i show you a picture of emma stone and you'll probably have no problem recognizing her. however, if i ask you to sketch or describe what emma stone looks like, it'll be much harder.",
"In your head you can make any sound you want because you're not limited by your actual body. Try having a conversation in your head between Morgan Freeman and Lois Griffin. Now try it with your actual voice.",
"Think of it like listening to a song you like, remembering how it goes in your head, but being unable to play it on an instrument. Over time, with practice, you can learn how to use the instrument and recreate the song you heard and like, but it takes time and practice.\n\nLikewise, speech takes practice to make the correct sounds you hear. A Japanese person who learns English in Australia (my friend is a good example since she studied there for 2 years) will hear the Australian accent and try to imitate it. Over time, with enough practice and exposure their English will have an Australian accent.",
"In my head I can do a perfect backflip. Turns out my body doesn't comply.",
"It's because your brain and body/mouth have no \"motor memory\" as it does for things it does often. The motor planning your brain has to do to do something more novel is much slower. ",
"I am Finnish.. I used to be able to do impersonations of different English accents (Texan etc).. Then I married American.. After 11 years together and speaking English every day. I speak fluent English but I lost my ability to do impersonations. I think the second language wrote over the part of my brain that was used for impersonations..\n",
"Its stored in completely different parts of the brain. Speech, mental rehearsing, words, and listening patterns have ALL their own sections and they aren't really near one another haha ",
"Sure, a big part of it is that your mouth doesn't know how to do it. However, the same thing happens even in your native language and it has nothing to do with your mouth. It's because one part of your brain handles understanding language, and another part of your brain handles making your mouth say something. The difficulty comes when the part that knows the words tries to communicate with the part that makes it come out - sometimes it's too much too fast, sometimes one part just isn't listening, or sometimes the information gets sent but gets lost on the way. ",
"It's like, \"I can hear every note of this guitar solo in my head but i can't actually play it.\"",
"You could probably also envision yourself breakdancing, but can't actually. I know I do, but I cant. :'-(",
"Also, I'm keen on singing perfect english, but it becomes less than perfect in an actual conversation.\n\nI think I'll just start to singing whatever I wanna talk.",
"Probably the same reason you can see stuff in your head, but when you try to draw it... Oh god... ",
"Same reason you can have a beautiful image in your mind, but getting it on paper doesn't come out as your vision. "
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adrzln | how do youtbers musicians/singers earn money from adsense if the song is not originally sung by them ? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/adrzln/eli5_how_do_youtbers_musicianssingers_earn_money/ | {
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"A performance can be a creative work in itself even if it is derivative, such as singing a song originally created by someone else. One person singing the song isn't equivalent to someone else singing the same song."
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4rirdk | multi-level marketing and amway. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4rirdk/eli5_multilevel_marketing_and_amway/ | {
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"It is too good to be true and you should be highly skeptical of it. They will tempt you with promises of wealth and references to anecdotes. While people can and do make money (even lots of money) these are extreme cases, not the typical experience.\n\nSome questions or things to consider:\n\n > A friend got involved with Amway and is making a lot of money\n\nHow is she making money? Selling a product or recruiting members like yourself?\n\nThis is key. If she's making money through recruiment, you know it's a scam. If she's making money through selling a product, then consider that if you take this on, you'll basically be competing with her. If she's successful in selling the product, then she already has a solid consumer base in your geographic area, and probably covers all of your mutual friends. You'd be at a serious disadvantage.\n\nA few years ago, Amway [released a disclosure statement](_URL_0_) that revealed that active Amway distributers earn an average of $115 a month. 0.26% (a quarter of a percent) earn more than $40,000 a year.\n\nMathematically, they can promise the world. Obviously if you sell enough product you can make any amount of money. The problem is that runs afoul of the brick wall of practical reality.",
"Beware. Succeeding within a pyramid scheme like Amway requires you to commodify your personal relationships. Money is made by tricking your friends and family to get involved. There's a great Always Sunny episode about this: \"Mac and Dennis buy a Timeshare\" season 9 episode 4 I think.\n\nPro tip: if its about money and seems too complicated, it's likely someone is trying to trick you. ",
"You make money not by selling things....but convincing other people to sign up under you.....and then have them convince more people to sign up under them....etc. The money then flows up like a pyramid. Unless you are really high up, you probably won't make much.\n\nIf you want to alienate most your friends and spend your time just trying to sell people on this, then go for it. You become full time sales people. \n\nBeware though. I once heard of a guy who drove a Cadillac, dressed in an Armani suit and wore a Rolex trying to get people under him in a pyramid scheme....but he also slept in that car, only had that one suit and the Rolex was a fake. \n\nBeware of what people say or show in the illusion of them being well off. You have been warned."
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1cdstb | paleo diet | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1cdstb/eli5_paleo_diet/ | {
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"The idea is that you're eating like cavemen ate. Specifically, you avoid ingredients that they wouldn't have had, and avoid processing food in ways they couldn't have done.",
"The gist, like /u/Amarkov has said, is to eat like our ancestors would have long before processed foods existed. Some folks try to be purists about it but I think it's silly because it makes costs start to run high trying to find uncommon ingredients and the reality is that you can't adapt it 100% in today's world so you have to compromise no matter what.\n\nGenerally it's a very healthy diet, though. I work at a hospital and I've had 2 doctors and a dietitian recommend it so I went ahead and I've been doing it for almost a year now. I was not doing too poorly health-wise to begin with (higher side of the normal range for blood pressure and cholesterol but not outright bad), but still have had much improved results on lipid panel, blood pressure, weight, etc. since my last doc's visit. Totally mid-range normal numbers instead of higher-side, now.. so even from an internal medicine perspective it seems to be a very positive diet.\n\nI follow some fairly simple guidelines that work pretty well: roughly 50% of your plate is non-starchy veggies like carrots, broccoli, and so on.. then about 25% is some kind of meat or fish. The remaining 25% is for sugary stuff like ideally fruit or something else mildly carby like legumes or dairy or whatnot. I can't personally have dairy due to allergies but I believe for most people some stuff is ok, like greek yogurt (I think-- conjecture on my part since I can't have it anyway). You generally want to avoid flour like it is a plague that will kill you.\n\nI aim for about 150g carbs per day in total. Some days are a little over, some are a little under, and that's fine. It's just sort of a target number since when you're on this diet you'll feel like absolute shit and go into a proverbial coma if you have too much sugar (you'll physically feel so horrible after eating junk food your desire to 'cheat' will vanish very, very quickly and you'll associate that donut with ohpleasegodnotagain instead of yummy) and you'll get cranky from low blood sugar if you have too little as you'd expect. Don't get me wrong, though, it's not a struggle to hit a 'sweet spot' at all.. it's super easy to do day-to-day. Just mentioning it since everyone gets those odd days where the office party has cake or you're crazy busy and have to skip two meals. Shit happens.\n\nI'm no expert but since I've actually been on the diet for nearing a year I can try to answer additional questions if anyone in the thread has any.",
"it goes like this -\n\n\"hey, want to have a healthy diet? just eat lots of unprocessed clean whole foods like fresh fruit, vegetables, lean meats and dairy. try to get a good balance in your macronutrients. there are mountains of research, studies, and anecdotal evidence backing up how effective this is.\"\n\naverage person: \"gee i dunno, that doesn't seem appealing.\"\n\n\"ok fine, want a healthy diet? eat lots of unprocessed clean whole foods because...uh...well some cavemen ate some of those foods too and that is pretty natural and buzzwords like 'natural' totally appeal to you right? plus i think dr. oz said some good things about it and there is a best selling book promoting it.\"\n\naverage person: \"wow! sign me the fuck up!\""
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5kcmfr | what's the difference between a heart beat and a pulse? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5kcmfr/eli5_whats_the_difference_between_a_heart_beat/ | {
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"A heart beat is a the physical beating of the heart. \n\nA pulse is the product: A momentary rush of blood through the blood vessels, which can be felt through the skin. "
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1oqjh0 | if feces and urine are just food/liquid we digest, how is it unsanitary and smelly? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1oqjh0/eli5_if_feces_and_urine_are_just_foodliquid_we/ | {
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"It's not just the food you digest; it's also other bacteria or particles in your body that your body decides to get rid of. So digesting those again could get you sick.",
"Smelly is just due to the chemicals in each.\n\nYou should probably categorize urine differently, at least when speaking of being unsanitary.\n\nWhile it would make something unclean, urine is sterile when it comes out of your body (as opposed to feces which is covered in bacteria).",
"Your intestines are full of bacteria that help you digest your food. We need them to survive and they're fine as long as they stay in your intestines. \n\nBut if they wind up in other parts of your body -- for example, if you eat them or your intestines get cut and leak -- then they can make you very sick and possibly kill you. \n\nThe smell is a side-effect of what the bacteria do, which is produce certain stinky gasses that create that familiar, awful aroma. \n\nFinally, you have to remember that the food that goes in generally takes a whole day to make the trip, so it's somewhat rotten and fermented in the process. Imagine leaving a meal sitting out in a room that's 98.6 F for a day. It would already start to smell bad on its own.",
"Chemistry. What comes out of you is no more food than car exhaust is gasoline. The food you eat is dissolved by gastric acid, pepsin, and other chemicals. This breaks the food down into base proteins your body can absorb. At this point, it's no longer anything that could be considered food. It's a kind of milky musch called chyme that gets pushed into your intestines so they can absorb the nutrients. \n\nTo do this, your intestines mix in bile (What you taste when you throw up), and a bunch of other enzymes (chemicals). You're basically looking at a chemical energy factory going on in your gut. The \"food\" part is long gone, except for any indigestible matter, ie peanuts/corn.\n\nThen it gets passed into your large intestine where everything stews for a while, letting your gut bacteria finish breaking everything down, absorbing what it can, and passing the remains (feces) down into your colon for removal.",
"I would also think that we have evolved to find certain smells \"bad\" because they are harmful for us--i.e., rotten meat, poop, etc.\n\nTo a fly, poop probably smells as mouthwatering as pizza to us."
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2vu8q8 | why are powers of 2 so important in computer science? | Had to explain why a byte is the best form of memory and realized i did not understand why it is in a power of 2. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2vu8q8/eli5_why_are_powers_of_2_so_important_in_computer/ | {
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"Because programming something to understand two states is really easy. A 0 or a 1 corresponds to off or on (respectively) referring to transistors. It is why [power switches](_URL_0_) were marked with a 0 and 1. The [Stand-by buttons](_URL_1_) are a mix of the two. ",
"Bits are the base of all the information in computers. A bit is binary, 0 or 1, base 2. Using powers of two is convenient because they convert easily. Hexidecimal for example is convenient because 4 bits can be converted to 1 hex."
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49qcdd | how does docker work? | I keep hearing how great Docker is. How is it different from VMware and how does it work? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/49qcdd/eli5_how_does_docker_work/ | {
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"With VMware, you have a disk image (VMDK) that is modified by the operating system of the running virtual machine. In Docker, you have a [docker image](_URL_4_), which is kind of like a read-only VMDK. When you [run](_URL_5_) a docker image, it launches a [docker container](_URL_6_) instance, which creates a unique, separate read-write layer (layers are kind of like mini-VMDK's) for the running OS to use.\n\nMuch of the Docker technology relies on features built in to Linux. For that reason, I don't believe it is possible to run non-Linux containers, and I don't believe you can run containers on non-Linux systems. The [OS X install tools](_URL_1_) actually leverage an Ubuntu VM running in VirtualBox. There's a version for Windows, but I suspect it uses a Linux VM somewhere, too.\n\nPart of the appeal of Docker is that it's very easy to create custom images using the [build](_URL_0_)/[Dockerfile](_URL_2_) syntax. Docker images are a collection of layers, so you might have an Ubuntu layer, then a Ruby layer, then a layer that includes your webapp. This can all be constructed in a Dockerfile that puts the pieces together. This results in an image which can be used to run containers just about anywhere: your laptop, a server in a datacenter, or on an instance in a public cloud. If the container runs your app successfully on your laptop, you can ship that container to a public cloud and it'll run exactly the same.\n\nMoving Docker images around is more of an ecosystem enhancement than a core technology, but it's a nice feature. Docker includes the [push](_URL_9_) and [pull](_URL_8_) commands that make it very easy to manage images in a central registry.\n\nOne important difference between VM's and Docker containers is the scope of executables inside them. VM's run an entire operating system, and can generally be treated as a server (or desktop) instance. Docker containers execute a [CMD](_URL_2_#cmd) and/or [ENTRYPOINT](_URL_2_#entrypoint) command when they launch. This means that a Docker container most likely won't have systemd, sysvinit, or upstart running by default, and you probably won't be able to SSH into a container to see what's going on. You have to configure a script or application to start the things you want to start.",
"How is it different:\n\nVirtual Machines engines VMWare simulate a computer inside your computer and runs a full Operating System on it.\n\nDocker runs a bunch of processes directly on your OS, and isolate them from the rest of a system thanks to a mechanism called cgroups (linux only).\n\nThis reduces the performance overhead (memory, network access...) but lowers flexibility (you can't run a Windows application in Docker but you can in a Virtual Machine for example).",
"Let's imagine your computer is a dining room and the food is computer resources (memory, cpu, disk space, i/o). Old operating systems served the food buffet style. ALL the food was put out and people just came in and had all they wanted. Naturally, people (programs) who came in later had less food to choose from.\n\nSo we upgrade the operating system to include some multi-tasking rules. And we teach people (programs) how to form a line, take only one plate of food at a time, and this makes things more fair and manageable. This works so well that soon we had rules (like \"please\" and \"thank you\" and asking people to \"pass\" things) that enabled everyone to SIT at the table and enjoy a nice dinner together. It was great -- as long as everyone knew the rules.\n\nBut kids don't know the rules. And often, kids can't understand the rules if you explain them. So the kids keep running into the room and grabbing whatever they want from the table, being greedy, eating from other people's plates, causing a mess and creating chaos.\n\nSo we create a \"kids table.\" (VMWare) This is a completely separate table where the children can sit and food is brought to them (they can't get their own). The kids are allowed to \"be kids\" and do what they want -- AS LONG AS THEY DON'T LEAVE THE TABLE. This keeps the adult table sane and pleasant, but someone DOES need to check in on the kids every so often. Most of the time the kids are sitting quietly, playing, doing their own thing. Sometimes, though, there's a \"Lord of the Flies\" situation and some cleanup is necessary.\n\nDocker, in this example, is for slightly older \"kids.\" Kids who are \"ready\" to sit at the adult table. Docker is the equivalent of saying to a program \"you can sit here but you do NOT speak unless spoken to, you sit up straight, eat slowly, no slurping, say please and thank you, do not tell that joke you know...\" These limitations allow the kid to BE at the adult table, while not really being an adult. It requires a different kind of management than kids sandboxed at the kid's table. Not really less or more, just different. \n\nThe advantage is that it's much easier to set an extra place at the table than to set up a whole other table.\n\nEdit: I hated how this was written. Re-wrote for clarity.\n\nThis is, more or less, the technical difference:\nIn vmware, programs are treated like wild animals who must be put in different cages to be fed or they would fight over their food.\nIn Docker, the programs are more like people at a restaurant, who know not to eat from their neighbor's table (or people at a thanksgiving table, who know which plate is theirs), and so are allowed to occupy the same room at meal time.",
"Dockers are a huge lifesaver when you need to run many virtual servers on a single machine. Say I have an application that can talk to other copies of that application on different servers. With a standard VM, I can only run a couple virtual machines before my box runs out of memory. But with dockers, I can easily run 10 servers on the same box, and they can all talk to each other. The drawback is that you have to preconfigure everything to install every time a docker starts. With a full VM, you can install at your leisure, and you don't have to constantly reinstall whenever the VM restarts.",
"Virtual machines require emulating/virtualizing hardware. There is, at best, limited integration between the kernel running on the virtual hardware and the kernel running on the real hardware. This leads to inefficient use of resources.\n\nDocker is a process sandbox that fools a program into thinking it's running on virtual hardware, when it's really still running on real hardware. Because there is no second kernel being virtualized on virtual hardware, the resources can be managed much, much more efficiently."
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2mkadh | why do i get those long lasting heavy 'flavour burps' even so long as the next day after having foods like meatballs or hamburgers? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2mkadh/eli5_why_do_i_get_those_long_lasting_heavy/ | {
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"Food can sit in your stomach for as long as 8-12 hours before being passed to your intestines. Depending how hard it is to break that food down.",
"You probably have low stomach acid and have problems digesting meat.",
"That's because when your stomach digests food, it makes a digested liquid called chyme. Not all foods and/or spices are broken down at the same rate; this is especially true when it comes to foods like meatballs/burgers that have a higher fat content in them and foods of Mexican or Italian origins. While breaking down foods, all of that gas has to go somewhere, which leads to burping. As those (now fragrant) gasses pass back through your upper digestive tract, many of those same chemical receptors responsible for taste get also triggered. "
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34maij | - what exactly makes the playstation 3 so hard to program for compared to the xbox 360? | I have heard from a lot of places that the PS3 is/was "a nightmare to program for," but no one can seem to explain exactly what it is that makes it that way. What about a game's code has to be changed to work with it and why is it so hard to do? It seems like developers who specialized in the PS3 could do some amazing things with it. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/34maij/eli5_what_exactly_makes_the_playstation_3_so_hard/ | {
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"The Cell processor architecture was radically different than a system built around a more traditional CPU. It required that progammers learn to use new tools and more importantly new coding techniques in order to optimize their code for the Cell. There was a very steep learning curve so it took quite some time for games that took full advantage of the architecture to be released.",
"Most processors, particularly the Xenos CPU in the Xbox360 are built with multiple identical multipurpose processor \"cores\" that share access to a big pool of RAM and they communicate primarily by writing stuff to RAM.\n\nThe Cell processor had one big multipurpose core called the PPU that talked to the rest the Playstation; the disk drive, GPU, network card etc. Connected to this big core were seven smaller, more specialised cores called SPEs that could talk to *eachother* very quickly through a high speed ring bus. But they had limited and pretty slow access to the rest of the system and everything that came in had to pass through the PPU. So you had to design your code in such a way that a task could be circulated through the SPEs with minimal external memory accesses or new task submissions through the PPU. \n\nMeanwhile on pretty much every other processor in existence your primary CPU architecture optimisation concern was to not trash your cache with excessive cache misses, something you also had to concern yourself with on the Cell. Task scheduling and memory accesses were much more simple on pretty much every other system than the Cell, just submit to the main queue, one of the cores will pick it up when it's free and return once it's complete. \n\nOf course if you got you code fitted into the Cell's curious pipeline those 7 SPEs could be wickedly quick, but in return you needed to completely rewrite that code if you wanted it to run on any other processor.",
"Xbox 360: three horses.\n\nPS3: one horse and TEN THOUSAND HAMSTERS. \n\nEveryone knows how to build horse-drawn sleighs, but hamsters are new territory. If you add up how much power you can get out of the system, the PS3 wins hands down, but the hamsters are hard to get organised and if you just naively take the sleigh you built for 360 and plug the PS3's one horse into it, ignoring the hamsters, it's not gonna work very well.",
"Well, people forgot the second problem. PS3 has a split memory architecture like a traditional PC.\n\nIn the PS3, you have to copy data to into the two processor private memory pool to do computation. The problem is that memory copy is slow on modern system. \n\nIn comparison, the Xbox 360 is a unified memory architecture which means that devs can specify the split with only a small pointer change. Pretend if a dev wants 350MB cpu ram while the gpu only needs 120MB ram.\n\n This is possible on the Xbox 360. This is also the reason why skyrim runs better on the 360 than the PS3\n\nSome other things. Microsoft debugging tools are amazing compared to Sony. this generation might changes a lot since mark cerny will never make his own life programming pretty miserable. ",
"Most of the other responses are very technical, so I'll try to keep this as simple as possible.\n\nAt the most basic, it boils down to the fact that the PS3 runs on a system that is relatively different from the X360 or regular PCs. The processing architecture is fairly unique, but the biggest difference is that, while the X360 has one single 512mb memory module, the PS3 has two 256mb modules - one dedicated to system processes, and one dedicated to graphics processes.\n\nLet's try to come up with a metaphor: there are two office buildings that are identical except for the elevators. Building A (X360) has one big elevator that services every floor, while Building B (PS3) has two smaller elevators, each of which services half the floors. You might think 'Hey, clearly Building B is superior because you can get to the floor you want faster - you don't have to worry about half the people in the building slowing you down because they'll be using a different elevator.' This is a great idea in theory - however, what if there are more people trying to use one elevator than can fit inside it? Everyone else gets left behind waiting, while the second elevator is useless because it can't reach the right floors. Building A never has this problem - it has a larger elevator that can fit everyone at once, and while it might sometimes take a little longer to get to the floor you want, you'll never get left behind.\n\nThis is exactly what happens on the two consoles. On X360, developers can choose how much of the system resources they allocate to graphics and processing, and if they need more of one they can just take away from the other. On PS3, however, you're always limited to 256mb for either - if your graphics are going to require more than 256mb of RAM, you're out of luck because the other half of your system memory can *only* handle processing. There are ways to take advantage of this and have excellent results (Beyond: Two Souls, for example), but it means that a game built for X360 or PC will almost always have big problems running on PS3 without some pretty major tweaks, which cause lots of headaches for developers/porters.\n\nThis is the main reason for the PS4 and XOne being essentially just PCs in smaller boxes - it's infinitely easier to develop games for them without having to worry about dealing with a whole separate architecture.\n\nSource: my job is to deal with stuff like this on a daily basis.",
"To elaborate on this, the main reason imo why Ps3's SPE (Secondary Processing Entity) is so difficult to work with is the crazy small amount of memory available (**256 kb!!**). That's not even enough memory to fit the main page of some popular news websites. Hell, even conventional memory on old x86 motherboard has 640k on it. The memory is so small that the devs have to literally start worrying about trimming down code size which introduce tons of ugly dependency hacks. The limited memory also means you can't really run a debug trace logger in there, which is the main technique to track down hard to reproduce bugs.\n\nOn top of that, because they exist in different memory space, you can't simply DMA (the method Ps3 use to copy data from primary processsor to SPE) any objects with v-ptr in there (since the v-table location won't match). And if the object contains a reference to another object, you have to manually patch up the reference by individually DMA each object. In the end, just a lot of ugly book keeping to do for something simple \n\nOn the other hand, every Xbox 360 core has full visibility of the main memory (the whole 512 MB), there is no need for DMA between the core, just a simple pointer deference and everything will just work. \n\nThe difference is simply night and day."
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47p984 | how does a helicopter actually attain lift? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/47p984/eli5_how_does_a_helicopter_actually_attain_lift/ | {
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"If you really want to understand the subject, the FAA actually has its Helicopter Flying Handbook available online here: _URL_0_\n\nThis goes into pretty good depth with all the aerodynamic forces at work, at different stages. \n\nHelicopters are pretty interesting because the way they attain lift is actually influenced by how fast they're going. \n\nELI5 Version: to lift itself off the ground, the rotors work like how you would think they would work, they push air down with enough force to lift the helicopter up. Once the helicopter is able to start moving forward, however, the spinning of the rotors creates a system where air currents move in a fashion that can be thought of as being closer to how an airplane works- it's not just the helicopter pushing air down, it's lift being generated by the system of air currents being generated by the downward force *and* the forward motion. At somewhere around like 40-50 knots (I might be slightly off on that) of forward airspeed, the helicopter reaches \"effective translational lift\" or ETL and the helicopter is able to fly (or, achieve lift) with much less power. \n\nIn the Robinson R-22, a small piston powered helicopter commonly used for training, it takes like 24 inches of mercury of manifold pressure to take off. Once you're flying, you only need to be around 18-20 inches of pressure to maneuver. ",
"Helicopter blades are the same shape as plane wings. Plane wings attain lift by differing air pressure above and below the wings. A helicopter takes these wing-shaped blades, and rather than drag or push them forward, it swings them around rapidly, which creates the same pressure difference, creating lift. The faster the blades are spun, the more lift is created.",
"Helicopters can lift off the ground in the same way that a person can swim. When we push our hands against the water we can get enough grip to move ourselves upwards or forwards a little before we begin to sink. If we move fast enough the continuous lift and forwards movement means that instead of sinking we move over and/or through the water. \n \nA Helicopter is very light but has a powerful engine. The blades are shaped so that when they are moved through the air quickly they can get a grip and push against the air in the same way that you push against the water when you swim. This allows the helicopter to move up and/or forwards/backwards etc. \n \nIf you were buoyant enough you wouldn't need to swim at all and the same is true for flight. However , a helicopter is a heavier than air flight vehicle and if the rotors stop turning it will drop. Even falling like a stone the blades of a helicopter will turn simply because the air is rushing past them as it drops so they still slow it down a bit. ",
"I have another question I've always wondered about helicopters if anyone would like to chime in. If a helicopter stays in the air long enough for the earth to rotate in the same spot, essentially would in land in the same space? ",
"Here are a few good videos of how the swashplate makes the helo... well, move:\n\n_URL_0_\n\n_URL_1_\n\n_URL_3_\n\nMute this one: _URL_2_",
"Schneiderman and audigex both gave great answers, so I won't repeat what they said, but want to add something interesting regarding helicopter blades and lift. What's fun to think about is that because the blades are rotating in a circle constantly, you always have some blades moving forward, gaining lift for the helicopter, and you always have some blades moving backwards, losing lift. It would be a zero sum game if not for the ability of the blades to change their angle of attack during the entire trip around, which is exactly what they do in order to not cancel each other out.\n\nThe blades moving forward are using an increased angle of attack (i.e. they're angles upward more), and once they pass the twelve o'clock position (front of the helicopter), they then decrease their angle of attack until reaching the six o'clock position.\n\nBy the way, I'm using angle of attack rather than pitch angle so as not to get overly wrapped up in details and confuse people. \n\nHere's a page that describes it with pictures, which might help.\n\n_URL_0_\n\n",
"Old helicopter joke:\n\nOf course the REAL reason helicopters fly is that they vibrate and make so much noise that the Earth rejects them.\n\nAnd I found this old quote from someone (it says Harry Reasoner, but not sure if it originated with him):\n\n\"The thing is, helicopters are different from planes. An airplane by it's nature wants to fly, and if not interfered with too strongly by unusual events or by a deliberately incompetent pilot, it will fly. A helicopter does not want to fly. It is maintained in the air by a variety of forces and controls working in opposition to each other, and if there is any disturbance in this delicate balance the helicopter stops flying; immediately and disastrously. There is no such thing as a gliding helicopter.\n\nThis is why being a helicopter pilot is so different from being an airplane pilot, and why in generality, airplane pilots are open, clear-eyed, buoyant extroverts and helicopter pilots are brooding introspective anticipators of trouble. They know if something bad has not happened it is about to.\"\n\nHarry Reasoner ",
"20 years aerospace engineer here including 12 on helicopters. \n\nHelicopters are called \"rotary wing\" vehicles because rather that being \"fixed\" in a single place like with planes, the wings rotate around the shaft. Just like with fixed wing aircraft, the faster the air goes across the airfoil of the wing (rotor blades) the more lift is generated. Now unlike fixed wings, the amount of lift varies quite a bit on helos because near the shaft the blade is moving relativity slow, while out on the tip it's moving fast (same time to cover larger circumference). Then in forward flight, the right side generates more lift (rotation+speed) while the left side generates less (rotation - speed). All of this is compensated for within the controls of the aircraft, and there's a lot more geometry that goes into controlling a helicopter, but that's the basics. ",
"The most basic answer is that the blades push air down. Because it pushes air down, a force must be reacted on the blades (newtons law) which is the force we call lift.",
"Sorry for the delay friends. While in a hover, helicopters create lift exactly like you would imagine. By manipulating a flight control called the \"collective\", you change the pitch of the main rotor blades, inducing flow downward. By creating thrust downwards, the helicopter hovers. Essentially, the thrust is overcoming the weight of the helicopter allowing it to fly. By pushing forward on another flight control, called the \"cyclic\", the rotor disc tilts forward. This directs thrust down and backwards which starts an acceleration of the entire helicopter. As the helicopter transitions into forward flight, air flows downward through the rotor disc and is then swept backward. This is called transverse flow. The entire rotor disc essentially acts as the wing of an airplane and creates lift to carry the helicopter in forward flight. The tail rotor exists entirely to counteract the torque created by the rotation of the main rotor system. The explanation presented above is tailored toward ELI5 and can be explained to a much finer detail. I recommend you search some of the terms used above to generate a better understanding. \n\nAll of the cliches used in this thread are incredibly silly and should be disregarded. Helicopters are amazing feats of engineering, none of which defy the laws of physics. While they are incredibly complex, they are easily explained.\n\nSource: Licensed Helicopter Pilot with over a decade of flying experience.\n\nEDITED: Elaborated",
"Does the ground have any effect on helicopter's flight? Or is the lift generated purely atmospheric? Meaning, if a helicopter is hovering high up in the sky, then suddenly, a ground appears like 2 feet under the helicopter, will it start to rise up higher? How about for aircraft like Harriers that use jets pointed towards the ground?",
"To explain it as if you really were five:\n\nIt's like they took two airplanes, tied them together facing different directions, and spun them really fast.",
"If you've ever held your hand out the window of a car on the highway you've experienced the effect that lets planes and helicopters fly. When you tilt your hand back you feel it lift up because the wind is pushing against your hand at an angle, forcing it up. Now instead of moving forward in your car, imagine your car is spinning very fast. You would still feel the wind moving passed your hand at the same speed and it would still lift your hand up even though you aren't technically moving. Replace your hand with wings and now you have a helicopter.",
"The shape and speed of the rotating blades means there is more air being forced underneath the helicopter than there is air above the helicopter.",
"Yo, this shit is always explained terribly. The correct answer is that for planes and helicopters both, air is thrown downwards, pushing you upwards.\n\nNow, how this is actually accomplished by a wing is a different question, and the one every other person here is trying to answer",
"The power of the spinning blades is enough to use air as a surface to push off of, resulting in lift. ",
"Aviation mechanic here, \nJust think of the main rotor like a giant fan, or better yet, a screw twisting itself in to the air. It works the same as a prop or wings on an airplane (fixed-wing aircraft). \n\nHeli rotors, props, and wings all use the same principles to produce lift. First we have air that runs really quick over the top of the AIRFOIL ( the rounded, front of the wing ) this creates a lower pressure zone which begins to suck the airplane upward in direction of LIFT. Because of the ANGLE OF ATTACK (angle of wing in relation with relative wind) the air hits the bottom of wing and also gives it a slight push upward.\n\nNow for controlling the helicopter..\n\nCOLLECTIVE increases or decreases angel of attack, which changes lift. This is what we use to go up and down.\n\nCYCLIC is controlled by the swashplate. This is how we go forward or backwards or any direction not up and down. The rotors turn into a gyroscope. Therefore to angle the swashplate in a certain direction, you have to input a force that is 90 degrees before the point you want it to angle towards. (In direction of rotation, 90 degrees, before the point of movement) a little extra I case you were curious ^^\n\nTail rotor uses adjustments in angle of attack for its compensation of main rotor TORQUE. \n \nAnd if we want to talk about balancing and CG (center of gravity) helis have a very narrow CG RANGE ( they are easily unbalanced if not careful)\n\nI'm sure there are great videos on YouTube you can watch.\n\n",
"This post is pretty darn hilarious. Someone already provided an accurate summation in one line: \n\n > The Bernoulli explanation and the Newton explanation are just two different perspectives explaining the same effect. \n\n...which is backed up after skimming articles about lift from NASA and other sources. \n\nThe rest of this should have its own sub: \"Argue like we're five\"\n",
"Do they even attain lift bro?",
"I feel like a simple gif showing how the air moves (using light blue arrows of course) around the blades might be the best way of explaining like one is five. None of the top answers were very helpful.",
"A helicopter is a fan pointed downwards.\n\n**reposted**: the bots tell me that this isn't sufficiently long (although I thought it was kinda elegant), so here goes: a fan pushes air in one direction, the reacting force pushes the fan back, but only a little bit, and so friction with the ground keeps it in place. Helicopters blow a whole lot more air much more forcefully downwards ---so strongly that the reacting force pushes the helicopter upwards. It's like swimming: push the water backwards and you go forwards.",
"The basis of powered flight begins with [Bernoulli's Principle](_URL_0_). Basically, gasses moving faster have a lower pressure. With that concept in mind, we then take a look at a wing's cross section, also called an [airfoil](_URL_1_).\n\nIf you'll notice, the top of the wing is more curved than the bottom. As the wing passes through the air, it seperates the stream over the top and bottom. Both streams of air stay in the same relative location in the air column, but the air moving over the top has to travel a farther distance across the wing. This means it is travelling faster that the current under the wing, and creates a zone of lower pressure. This is what generates lift: the wing being pushed upward by higher pressure air.\n\nNow, take that wing, put it together with a bunch of other wings pointed in the same direction around a central axis, and voila, chopper rotors.\n\nCheers!",
"When I was helicopter logging I asked a pilot how come he could lift heavier loads on wet days than on dry days? He said the more humidity the more lift. The helicopter literally swims through the air.",
"A flight instructor of mine, an ex-navy 'copter pilot, said that helicopters don't so much fly, as beat the air into submission. ",
"Imagine each blade as a small wing. Pilots can control the angle of the blades to control how much lift the helicopter generates.",
"The rotors are angled to the ground. They work like a fan, blowing air down. If they rotated in the opposite direction, they'd push air up and push the helicopter down.\n\nLook at this slash / and imagine it's a helicopter rotor, when you're looking at it from the end.\n\nWhen the thing is moving this way == > / it hits air at an angle / and the air is effectively moving counter to the blade / < ==this way, hits the blade, and reflects downward, just as a pool ball would if you hit it at an angle against the rail....except in the case of the air, it's like trillions or more of tiny pool balls, all being reflected downward by the angle and movement of the spinning blades.\n\nAccording to the laws of motion (set out by Newton), a force in one direction must generate an equal and opposite reaction, so by reflecting all that air downward, the helicopter is actually pushing itself up. This is the same as when you shoot a gun, there's a recoil--you can't propel the bullet forward without feeling that same force push you backward as well. Or if you push something you might actually be the one to move backward, if your feet are less steady, because the force of the push actually is felt by both of you in opposite directions.\n\nSo yeah, essentially by running a fan pushing air downward at the ground,you are causing that same air to push you back upward on the blades of the helicopter, and this force holds the helicopter up.",
"Definition of a helicopter: Five-thousand moving parts, all working against each other, held together by one \"oh shit\" bolt. ",
"Late to the party, but the body of a helicopter doesn't actually fly, it's attached to the rotor disk which is the main source of all aerodynamics (there are others like the tail rotor, sync elevator, drag associated with the body, etc. but they aren't as important) \n\nThe rotor disk is what's actually \"flying\" it does so largely in the same manner as a propeller on a regular airplane. The blades of a helicopter are airfoils that create lift as they move through the air the same way normal wings do, the only difference is they rotate around the mast instead of moving in a straight line. \n\nA pilot changes the pitch on the blades to increase or decrease the amount of lift being created which results in moving up and down. In order to move forward, backwards or side to side the pilot manipulates the plane that the disk creates, so essentially tilting the disk in the direction of flight so lift vector is pointed where you want to go.\n\nDue to the rotation of the blades some really cool and funky stuff happens. The main rotor creates a lot of torque so a tail rotor is added to counter it and keep the nose controllable. If the helicopter is moving through the air (ie, not in a no-wind hover) then one \"side\" of the rotor disk creates more lift than the other due to increased relative wind. There are several ways to counter that depending on the type of rotor system the helicopter has.\n\nI love this stuff and could talk all day, so let me know if you have more detailed questions. I'm a helicopter pilot and I've learned that the more you learn about helicopter aerodynamics the less you actually understand how they fly.\n\nTL;DR: PFM (pure fucking magic)\n\nPS: all the jokes about a helicopter beating the air into submission, and just being a thousand pieces rotating in close formation around an oil leak are 100% true",
"A helicopter generates lift by spinning it's \"blades\" around in a circle. These blades have an airfoil, much like a wing so if you look at them from the side, they'll closely resemble the same shape as an airplane wing. \n\nBut that's not all. A helicopter uses something called \"collective\" pitch. Spinning the rotor blades alone will not generate lift but it will smooth the airflow over the blades in an efficient manner. \n\nWhen the pilot wants to generate lift, he pulls up on the collective lever in the cockpit. This causes the angle of attack of the blades to change, thus \"biting\" into the air and generating lift. The pilot can change his collective as needed to generate more or less lift. Thus changing the angle of the blades.\n\nThe angle of attack of rotor blades change constantly as they move around the 360 degrees of rotation constantly, depending on the flight attitude. The flight attitude is controlled by the \"cyclic\". The cyclic is controlled by the stick in the cockpit and actually tilts the entire rotor head assembly where the blades are attached, this further changes, and lessens the angle of attack of the rotor blade at any given location around its 360 degrees to give the pilot his needed attitude.\n\nRotor blades can stall much like airplane wings can stall, a stall is where the airfoils angle of attack has exceeded the maximum amount of airflow over the airfoil causing a stall to occur. \n\nThe tail rotor is attached to the main rotor drive assembly via a driveshaft, it is to counter the torque caused by the main rotor. How helicopters turn left and right is much like the main rotor. The pilot pushes on the pedals and causes the pitch or \"collective\" of the tail rotor blades to change which forces the tail of the helicopter left or right, depending on what the pilot needs.\n\nHelicopters are scary and shouldn't fly.",
"So you know how a fan blows air? Imagine a VERY strong fan, blowing down.\n\nIf it blows hard enough, it will push itself up in the air."
]
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"https://www.faa.gov/regulations_policies/handbooks_manuals/aviation/helicopter_flying_handbook/media/helicopter_flying_handbook.pdf"
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[],
[],
[],
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"https://www.youtube.com/watch?v=I9ScVZ437xA",
"https://www.youtube.com/watch?v=04tJmP2aqcw",
"https://www.youtube.com/watch?v=rJb1EZtnzFk",
"https://www.youtube.com/watch?v=83h6QK-oJ4M"
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"https://www.faasafety.gov/gslac/ALC/course_content_popup.aspx?preview=true&cID=104&sID=449"
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"https://en.m.wikipedia.org/wiki/Bernoulli%27s_principle",
"https://en.m.wikipedia.org/wiki/Airfoil"
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||
3ehida | why is the following a false counter example of the four color theorem? | _URL_0_
As the four color theorem states, that map should be colorable by only 4 different colors, but I cannot see his that can be done here. Can someone please explain what I'm missing here, this was stated as if it was obvious :( | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/3ehida/eli5_why_is_the_following_a_false_counter_example/ | {
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"You only need 3 colours so that you can colour it with only different colours touching\n\nColour 1: A\n\nColour 2: B & E\n\nColour 3: C & D",
"Are you sure that that's the correct image?",
"Easy. Either regions B and E are the same color or C and E are the same color since neither of those pairs of regions touch.",
"Holy crap thanks everyone! Although, now I have no clue how I'm going to survive my major :P"
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"http://imgur.com/kaCVLJK"
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3rvtfo | are move trailers released after the movie is done being filmed or during filming? | Edit: Oops, misspelled movie in the title. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/3rvtfo/eli5are_move_trailers_released_after_the_movie_is/ | {
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"They are released well into the post-production process. The editing, sound, and effects for the complete film need not be complete, but the trailer needs to be made up from finished pieces of the film.\n\nIn some cases, they'll have a storyboard for a trailer ready and prioritize finishing those bits of film first, so they can get an early trailer (or at least teaser) out. Many times they will put a trailer together from what bits of the movie are finished by a certain date in the post-production schedule.\n\nYou can't really cut trailers while filming is going on as there's really just too many things that could affect the production and too much work that needs to be done in editing.\n\nThe one thing they want to never do is create trailers with scenes that are cut from, or look substantially different than, the final film."
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8rfp9r | how fiber optic cable is run in a neighborhood | How are Fiber optics physically run in a residential neighborhood? Are they set up like phone lines, where you have a main trunk line going to a cabinet and then every residence connected to that cabinet gets their own dedicated line? Or is Fiber run completely differently?
Edit: I should probably specify i'm asking about Fiber to the home deployments. Not Hybrid fiber networks | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/8rfp9r/eli5how_fiber_optic_cable_is_run_in_a_neighborhood/ | {
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"I can tell you how att does it. They have a huge fiber line that goes from where its generated to a \"cabinet\" then they have smaller fiber lines that go to terminals in neighborhoods. Then a technician goes to the terminal and connects a fiber line from the terminal to the house that wants internet. The fiber line is about ground for about a month then the \"bury crew\" trenches it into the ground... Or when a neighborhood is being made they have preplaced fiber lines that are out there while the houses are being built. ",
"Most residential fiber deployments (at least, the ones I'm familiar with) use a Passive Optical Network (PON).\n\nIn broad terms, yes, it's similar to copper networks where the main fiber is run to a cabinet in the neighborhood, with more individual fiber strands run from that cabinet to the individual residences underground or on poles.\n\nThe \"Passive\" part is the main difference: the cabinet contains optical beam splitters, basically prisms, which split the light signal from a single upstream fiber strand and sends copies of it down several downstream fibers to the optical network terminal (ONT) in each house. There may be another passive splitter on a pole or in a hand-hole closer to the house, splitting a single fiber down into even more individual fibers that go to individual subscribers."
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668hre | why can lying in weird positions (such as having one leg hanging off the bed) be really comfortable? is there an actual reason or just one of those random things? | This is a weird one, I know. I was lying in bed diagonally with one leg off the bed and was super comfortable so I thought I'd take to Reddit to ask why :) | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/668hre/eli5_why_can_lying_in_weird_positions_such_as/ | {
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"IANAD, and somebody more well-versed in human anatomy and physiology may be better suited to answer this, but in my brief explorations of Google, and via my own experience, I've come to this conclusion: the weight feels good. \n\nTo probe this in further depth, I Googled weighted blankets and their uses. These are blankets that have small weights stitched into them, and are used primarily to help people sleep, or ease people with anxiety disorders, sensory disorders, etc. When under the blanket, the weight of the blanket stimulates deep pressure touch receptors throughout the body, which in turn increase serotonin and melatonin levels. These are hormones that, among other jobs, help you sleep. Your body feels more secure and safe when these receptors are triggered, like when you get hugged, or how swaddling helps comfort and calm a restless infant. You feel more comfortable with the extra weight on your body. \n\nGetting back to your question, I think dangling your leg off the bed triggers the same sort of deep pressure touch receptors that weighted blankets do, by way of gravity and the weight of your leg dangling off the bed.\n\n\nTL;DR: more weight feels good. "
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bt878l | how do they determine lethal doses of pharmaceutical drugs? | I've just watched a documentary investigating a woman who died due to an unknown cause. It's mentioned that she was on some medication, but the dose in her blood was lower than what is lethal. How do they check how much of a particular medicine it takes to kill a person without killing a person?? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/bt878l/eli5_how_do_they_determine_lethal_doses_of/ | {
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"I believe they use something called LD50 (lethal dose 50), which is how much of a drug is considered a lethal dose to kill 50% of the population. This is tested on animals. So for example, if in a study of 30 rats, 5mg of a drug killed 15 of the rats, this would be the LD50. This amount is then adjusted for the average weight of humans. Let's pretend that the average human weight is 100 times that of a rat, the LD50 for a rat would be 5mg, and the LD50 for humans would be 500mg.\n\nEdit: changed 50mg to 500mg",
"Weight of a lab rat compared to the weight of the dose issued. Then compare that to the weight of the patient and the dose will be adjusted to be under that.",
"The data comes from experiments in rats and mice. But, there is also data for medicines that people commonly overdose on. There are thousands of people every year that intentionally take overdose on medicine for self harm, and that data can give you an idea of an LD50, based on how much those people were taking and how many of them died."
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2l8spn | guy fawkes and the gunpowder plot | Solved...Self explanatory. Just the basics. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2l8spn/eli5_guy_fawkes_and_the_gunpowder_plot/ | {
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"The British government was being sectarian. Guy Falkes was being the other kind of sectarian. Attempted terrorism ensued.",
"The Gunpowder Plot was a plan to blow up the House of Lords during the State Opening of Parliament, killing James I, the Lords and most of Parliament. The aim was to remove James I as Monarch and replace him with his daughter Elizabeth as a puppet Queen. \n\nThe Conspirators were unhappy with the treatment of Catholics in England, and wanted to make England Catholic again. Guy Fawkes was one of the conspirators, and is by far the best known of the group .\n\nThe Conspirators rented a cellar underneath the House of Lords (yes, you could do that in the early 17th century) and gradually filled it with barrels of gunpowder covered with firewood to disguise it. Fawkes had the job of guarding the gunpowder. At the opening of Parliament, he was supposed to light the fuse and then escape in a boat over the Thames. (Not die in the explosion.) \n\nThe Plot failed because one of the conspirators decided to warn a Catholic relative, William Parker, 4th Baron Monteagle (not the King), to avoid the state opening of Parliament. Parker immediately informed the authorities, who decided to search the cellars. Just after midnight on 5 November, Fawkes and the gunpowder were discovered. \n\nFawkes was captured, along with the other conspirators and tortured. They were then sentenced to die by hanging, drawing and quartering (not burning) which was the standard execution for traitors. Fawkes avoided this death by jumping from the ladder on the gallows, breaking his neck. \n\nFawkes has more recently been appropriated as some kind of popular hero in V for Vendetta and so on. He had no intention of establishing a fairer country, liberating 'the people' or anything of the sort. He was planning on killing all of Parliament and establishing a Catholic autocracy with him and other conspirators as the power behind the throne. \n"
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57owwv | why is the phrase or question 'aren't i' used at all in the english language? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/57owwv/eli5_why_is_the_phrase_or_question_arent_i_used/ | {
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"Because for 3rd person pronouns (he/she/it), we can say \"isn't\" instead of \"He is not cute\"\nFor I there is no equivalent. We can't say \"amn't\" instead of \"I am not cute\"\n\nInstead we stole aren't. I'm not too sure why that became better than amn't"
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27b9vg | tienanmen square | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/27b9vg/eli5_tienanmen_square/ | {
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"Check wikipedia.\n\nA bunch of college aged Chinese students protested the government by camping out in the square for days demanding the government make democratic reforms. After negotiating with them, the government decided to use force and had the army shoot the protesters and run them over with tanks to clear the square and restore control. A few western journalists got pictures and video out of the Chinese government slaugting their own unarmed people for asking for more freedom. China looked very bad. \n\nSince then, China has done everything to erase this even from history, including banning and books that mention it and censoring any info on the highly restricted state run Chinese internet. \n\nTL;DR Chinese government had the army kill unarmed protesters and now China is trying to act like they didn't do that. "
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5ahzsg | what is carbon-12? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5ahzsg/eli5_what_is_carbon12/ | {
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"It's a stable isotope of carbon where the sum of neutrons and protons equals 12(6 and 6 in this case). As opposed to Carbon-13 which has the sum total of 13(7 Neutrons, 6 Protons). It's by far the most abundant Carbon isotope. C-14 exists but decays over a long period of time into another element(and is used to carbon date things) and a few other forms can be created in a lab with various half life but will all eventually decay into other elements."
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2x4w3j | batteries: how can a aa battery only supply 1.5 volts, but a 9v supplies 9 while not being much larger and then a car battery is very large but supplies 12 volts? | Does it have to do with P=IE? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2x4w3j/eli5_batteries_how_can_a_aa_battery_only_supply/ | {
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"In general, an electrolytic battery cell of any size only makes 1.5 volts. Bigger ones have more capacity (amp hours) or current (amperage), but not more voltage.\n\nA 9v battery, is 6 separate 1.5v AAAA (yes, \"quadruple A\") batteries wired in series, all contained within a single case. 1.5v*6=9v. If you open the case, you can pull out the batteries and use them individually (car alarm keypads use these, which is how I learned this).\n\nA 12v car battery is made of 8 separate 1.5v cells wired in series (EDIT: 6 separate 2v cells, as per posters below). The cells are physically much larger, which is why a car battery has so much more current (amperage) and storage (amp hours) than your typical household batteries.\n\nIf you've ever seen 12v camera batteries (a23 is the size I know off hand), those are actually 8 separate 1.5v miniature watch batteries stacked in a single housing. ",
"If you make a battery larger, you can use that extra material to increase the voltage *or* to increase how much current it can deliver before it runs out.\n\nYes, 9v batteries do have a high voltage for their size, but they can't provide much energy (i.e. amp hours) before they're dead. \n\nSure, car batteries are big and low voltage, but they can run your bright headlights for hours and hours with the engine off. If you tried sticking 8 AA batteries in series, you would also get a 12 volt battery, but it would die really soon if you tried to run your headlights off of it.",
"The question has mostly been answered, but I think I can give a bit more detail.\n\nFirst, there are a few different kinds of chemical reaction used to make batteries, and they all produce a different amount of voltage. Alkaline cells are around 1.5 volts. NiCd and NiMH are 1.2 volts. Lithium cells, depending on the specific type, are between 3.2 and 3.8. Lead-acid cells are 2 volts. You notice I call them *cells* rather than *batteries* - a battery is a collection of cells. AA and AAA \"batteries\" are misnamed, because they have just a single Alkaline cell in them. But 9v batteries are true batteries, usually made of 6 AAAA cells. You can make cells and batteries as small or large as you like, like a teeny-tiny 12v [A23](_URL_1_) battery, or a huge 2v [forklift traction cell](_URL_0_)\n\nSecond, despite what cordless tool manufacturers want you to think, voltage isn't power. Voltage is only half the story, with current being the other half - multiply volts and amps together to get watts, which is a form of power. So let's talk about current. There's a lot of variation in this, but for our purposes let's say current is proportional to the size of the cell. It varies for each chemistry of battery, but it's probably true within an order of magnitude. Bigger cell, more current. Smaller cell, less current, but we can put more cells in the same area - for most purposes, the size of the battery is related to the total power it produces. By adjusting the size and number of cells, we can design it for high voltage and low current, or for low voltage and high current, but when we multiply those back together we wind up with the same power.\n\nSo, back to car batteries. They're big, but surprisingly low voltage (hence your question). There are a few reasons we use 12v batteries in cars, but they're more complicated than we need to worry about. All that matters is that we standardized on 12v car batteries, so that's what everything is designed around. It takes a lot of power to start a car, so the batteries used are big. And they're 12v by standardization, so they're designed to make a lot of current at low voltage. You could stack two 9v batteries together to get 18v and they still wouldn't hold a candle to the kind of overall power a car battery can churn out."
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2ex6rm | a versus an, the english language | I know that English is a perpetually exhausting language when in the written form, but I have found myself trying to understand the rules of linguistics as they apply to English, and I was wondering the following:
If we use AN before a vowel (an answer), why don't we use it before U sometimes? Ex: A useful answer
I think it has something to do with the y sound of the long u, but could someone please ELI5? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2ex6rm/eli5_a_versus_an_the_english_language/ | {
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"The easiest way to think of it is that \"an\" is used before a vowel *sound*, not literally before a vowel. So \"useful\" begins with a \"y\" sound, which in this case functions as a consonant (the same as in the word \"you\" -- \"y\" is clearly a consonant here).",
"I think the basic rule is if the first sound of the word is a 'vowel sound', then it's 'an', if a consonant then it's 'a'. As with English there's always exceptions. ",
" > If we use AN before a vowel \n\nWe don't. We use \"an\" before a vowel **sound**. So \"an hour\", because \"hour\" starts with an \"o\" sound.\n\nLikewise, we use \"a\" before a word that starts with a consonant **sound**. So \"a useful answer\" because \"useful\" starts with a \"y\" sound.",
"Yes. You use AN before a vowel sound. Not necessarily a vowel letter. Your example of U is perfect, since in words like useful or usual, the letter U doesn't produce a vowel sound but is a consonant sound.\n\nHaving AN instead of A is useful since you are pronouncing two vowel sounds one after another, making it easier to decipher the word.",
"The \"a\" vs. \"an\" rule applies to the *sound* the first letter of the word makes or, in more complex cases, the sound the first *syllable* of the word will make. It has nothing to do with what the first letter actually is. \n\nSome people take issue with words starting with the letter \"h\". Examples: \"An hour.\" \"A historic event.\"\n\nI use these two as examples because back in the day, it was common for people to leave off the stressed \"h\" on words such as \"hotel\" or \"historic\". Such is not the case today as we've starting stressing these consonant sounds. ",
"The english language has so many exceptions and what not. Think of it this way. If it SOUNDS like it starts with a vowel, always use 'an.' \n\nAn hour. Hour starts with 'h', but since the H is silent we only pronounce 'our'. \n\nA university. University starts with a 'u', but since it's pronounced YOO-niversity, it doesn't have the hard 'u' vowel sound. "
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d2txgv | why the key of a piece of music makes such a big difference. | I know next to nothing about musical theory. Torturous, mandatory participation in musical endeavors in youth taught me how to read music and the very fundamentals.
Why does changing the number of sharps and flats in the key so dramatically change the entire sound of the piece? Why is the key so important that famous pieces of music are billed as “Such and such in G major” or whatever?
I mean I know that some of the notes will be half a step higher or lower depending on what the key falls for. But I can’t imagine why that changes so much. I’ve heard songs like The Star Spangled Banner and other famous works played in a minor key and it completely changes the entire sound. How? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/d2txgv/eli5_why_the_key_of_a_piece_of_music_makes_such_a/ | {
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"When you play a piece normally in a major key in a minor key instead, it completely changes the melody. You are changing *some* of the notes played, but not others. This results in a very different sound.\n\nYou can also *transpose* a piece - that is, shift *every* note up or down by the same amount. An example would be playing a piece in C major in F major instead. This *might or might not* change the sound significantly, and the reason is tuning.\n\nTuning is the relationship from one note to the next. Prior to the 20th century, many different kinds of tuning were in use. The distance from C to C# was *not* the same as the distance from F to F#. Thus, if you played a piece in C major in F major instead, you would once again be changing the melody because the relationships between the notes would be different.\n\nIn the early 20th century, *equal temperament tuning* became almost universally used. This is a tuning where the ratio from one note to the next is always the same, no matter where in the scale those notes are. Thus, transposing from C major to F major would not significantly change the sound of the piece, because the relationships between all notes would be the same; the piece would just be played higher.\n\nHowever, playing a piece higher or lower than usual *can* change the sound a bit, because notes in a very low or very high register get perceived a little differently. A piece which is normally played around middle C would sound quite menacing if played several octaves lower, even though the notes are the same; and quite shrill and chintzy if played several octaves higher.",
"When you hear music, you hear two things. The note, and the distance between the note and the next note (and next note and so on). Music written in a certain “key” will sound as it sounds because we hear the notes, and intervals, as they were intended.\n\nChanging the key, otherwise known as “transposing,” will change the note BUT WILL NOT change the interval between notes. Thus, the piece will still be recognizable. They “sound different” because the notes are different, each note having its own rich overtones and undertones. But \n\nHowever, when you change keys into a MINOR key (from major, or vice versa), you have changed (some of) BOTH the notes and the intervals between the notes. The piece of music will thus sound different. A half-decent ear could still “pick out” the original piece of music, as the original (especially if we have enjoyed it/listened to it many times) will still be in our memory. But the sound colour is fundamentally different.",
"Changing between related keys, like G major to C major (known as transposing), won't actually make that much difference; It'll sound the same, just higher or lower than before, like when you play a song faster. This is because the distance between the frequencies hasn't changed.\n\nHowever, going from G major to G minor will definitely make a difference since you've changed the scale it's played on and thus, the distance between the frequencies. The way these frequencies interact (harmonize) is what makes them sound happy (major), sad (minor), etc."
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72xswz | how buying items on black friday are specifically, and cheaply made for that day and/or retailers | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/72xswz/eli5_how_buying_items_on_black_friday_are/ | {
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"Its not really just for black friday. A lot of companies make products at lower cost and lower quality to be sold at sales or discount stores or outlet stores and such. It has their brand name on it, it is made by them (usually), its just a lower quality than their standard products. Does not mean anything is wrong with the product, its just going after a lower priced consumer market.\n\nCothing companies are well known for this, as many name-brand clothes you find at discount clothing retailers that are marketed as the name brand but say \"50%\" off since its at a discount store (and presumably didn't sell in a regular store so they are trying to get rid of it, aren't actually that, in fact they were specifically made to be sold at these discount stores, and never were elsewhere.\n\nBut again to be clear, nothing is wrong with these products, if it meets your needs and price point, have at it."
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3d86um | how does nasa calculate or determine a planet's properties? | I saw the post with a blue planet that rains glass. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/3d86um/eli5_how_does_nasa_calculate_or_determine_a/ | {
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"I assume this is an exoplanet, haven't read the article.\n\nIn a nutshell: \n\n* You can determine the mass of an object orbiting a star if you know the stars mass and the distance between object and star - in the simple form that's 9th grade math.\n\n* You can find out atmospheric properties by \"looking through\" the atmosphere. If the planet is right in front of it's star, you can see how light is absorbed. Different molecules/elements absorb specific wavelengths.\n\n* Temperature can either be calculated by combining knowledge of the star, distance and atmospheric properties or by measuring infrared radiation of the object( though, I doubt our technology can do this for exoplanets).\n"
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15mzxu | speaking of dogs, why don't dogs (seem to) account for their own size or other dogs size when determining social ranking? | Having spent a bunch of time at dog parks, it seems to me that dogs don't take size into much account when 'sizing' each other up. Is that true or just my imagination? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/15mzxu/eli5_speaking_of_dogs_why_dont_dogs_seem_to/ | {
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"It's not the size of the dog in the fight, but the size of the fight in the dog. ",
"Probably because dogs instincts are mostly honed through all the centuries they were wolfes. Only recently have there been a meaningful size difference between them.",
"I don't think large dogs see small dogs as a threat but small dogs seem like they always have something to prove.",
"In many cases, humans encourage this oddity in social ranking. Small dogs, being little, are allowed to do things big dogs aren't. As they're easy to carry or hold, when a small dog begs to be picked up they often are. A small dog might jump around someone's feet, or put their paws on a person's legs. These things big dogs aren't allowed to do (because they're to heavy and could hurt someone). What this translates to a big dog is: the small dog, for whatever reasons, is allowed by owners to do things the big dog is not allowed to do. Therefore, the small dog must have a higher ranking. I believe a small dog, in turn, is able to somehow convey that they have these privileges to bigger dogs.\n\nEdit: Grammar",
"I've got three dogs, all mutts but easy to label them as Chihuahua, Husky and Border collie/great dane. Gotta put the last one's mix so you get a size reference.\n\nThey've been living together for three years now and here's what I see. It's not about the fight, you're not talking about a fight, you're talking about 'sizing' up. When the dogs do this they aren't looking (I assume) at things like size, they are looking at tension, position of the tail and eras, bared teeth, etc. Warning signs that the other is about to attack.\n\nFrom personal experience fostering over 100 dogs and puppies I see that little dogs tend to be more agressive, whether this is bred in, or just a defense mechanism I don't know, they just tend to be quick to growl, snap and bare their fangs along with other signs.\n\nThe bigger dogs tend to be more laid back so when the little dog growls at them when they go by, the big one just ignores it or backs off.\n\nHope that helps, if you could better explain the situations you observe I could offer more insight. Are we just talking about visually sizing each other up, snapping at each other, mounting, etc. There's a lot of ways dogs display themselves. For example, we had a foster dog, a girl, that kept humping another foster dog-among other things, it meant she was a very dominate personality so we had to specially place her in a home with no other dogs because she ran the risk of fighting another dog for dominance."
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besczw | why didn’t the makers of pepsi-man sue the games which 75-85% copied them. such as temple run & subway surfer etc. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/besczw/eli5_why_didnt_the_makers_of_pepsiman_sue_the/ | {
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"Game mechanics are not something that can be patented. Specific implementations can be, such as Namco having a longstanding patent that recently expired on loading screen minigames, but general concepts such as \"Running man avoids the things\", you're simply outta luck."
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70ls4y | what gives elements and compounds their properties on an atomic level, and why do they react to each other in different way? (p.s. i hope this is the right subreddit for this question, if not please let me know, and thank you.) | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/70ls4y/eli5_what_gives_elements_and_compounds_their/ | {
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"I know there are many nuances regarding the behavior of compounds (IMFs, weak forces, etc.) but the primary rule that governs EVERYTHING (life, the earth, the solar system) is the octet rule. Every atom has these things called electron shells that orbit around the nucleus, and for some reason, they want them to be filled up with electrons. For Hydrogen, it wants to have two electrons but it only has one. Oxygen, on the other hand, has 6 in its outermost shell but wants 8. Here's the thing: atoms long ago realized that they can share electrons to satisfy everyone. The hydrogen will share its only electron with one of oxygen's so that both electrons end up in their shells. (it's like both electrons are simultaneously in both of their shells at once). Now there are 7 electrons in Oxygen's shell and two in the Hydrogen's shell. So the Hydrogen atom is happy but the Oxygen one is not. What it does is it pulls over another Hydrogen atom to fill its shell and everyone's happy. This is called a Covalent bond, and it's an important building block of many compounds that make up living organisms (as well as other things). \nSome atoms want full octets and have only one electron (like sodium), while others have 7 electrons and need one more (like chlorine). What they figured out is that if the atom with one electron gives the electron away to the atom with 7 electrons, they will both be happy. This type of bond is called an ionic bond, and is present in salts and solutions (things dissolved in water). \n\nI hope this answers your question!",
"Let's try this.\n\nBroadly speaking, elements are defined by the number of protons they have. Following on to this, this tends to also define how many electrons they have, since charge-neutral atoms tend to be more stable.\n\nNow, trying to squeeze so many mutually-repulsive electrons around a nucleus is challenging business, and there's only so many ways it can be done. So these electrons tend to fall into certain arrangements, according to the number of electrons you're trying to squeeze in there.\n\nAn element's chemical properties are largely determined by the arrangements of these electrons, since the electrons are generally the bits that interactive with the neighbours.\n\nIn short, number of protons -- > number of electrons -- > arrangement of electrons -- > chemical properties.\n\nSource: some basic chem and physics courses at uni."
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1d2tzf | why do i get hiccups when i eat too quickly? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1d2tzf/why_do_i_get_hiccups_when_i_eat_too_quickly/ | {
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"I'm no doctor, but I would assume it's because you eat too quickly.\n",
"The stomach, which is situated right below the diaphragm, becomes distended (swells) and irritates the diaphragm. This will cause the diaphragm to contract, as it does when we breathe in. \n\nYou can get rid of them by exhaling as much air from your lungs as possible and then swallowing twice. If you do it right, the second swallow will feel nearly impossible. This will allow your muscles to push on your diaphragm to stop the spasms."
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2s5u0k | what caused babys to die in (e.g. medieval age) so often at birth? why didn't it happen so often to animals? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2s5u0k/eli5_what_caused_babys_to_die_in_eg_medieval_age/ | {
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"Disease, sanitation, and nutrition, baby animals don't require as much as humans in terms of care",
"It did, and does happen as often if not more often with animals. Any animal species that commonly births multiple offspring has a high infant/juvenile mortality rate in the wild. \n\nWhat caused so many infants to die during earlier points in human history was lack of modern medical knowledge/care, contaminated water/food, and the spread of disease, famine.",
"A lot of people are mentioning sanitation, and I wanted to add to that.\n\nIt wasn't too long ago that we started washing our hands. The first doctor to suggest doctors should maybe wash their hands between visits to the morgue and the maternity ward was laughed out of the medical community.\n\n\"A doctor is a gentleman, and a gentleman's hands are never dirty.\"",
"A good reason for why those problems plagued us in the middle ages is because society had advanced to a point where we had new problems with little solutions and actual care.\n\n A large portion of society was now stagnant in cities, sharing the same resources and land without being spread out. This kind of stagnant population density introduces a lot of health problems due to a lack of sanitation and frequent contamination. The most vulnerable populations to these conditions are infants and elderly because at those stages of life, the immune system is weakest. This made us a species whose primary death causes for infants were results of our own making rather than the environment or predators, like other organisms with high birth and infant mortality rates.\n\nThis was compounded at the time by the class and power structure. The ruling class could afford housing and land and staff that allowed them to avoid the problems of living in villages and cities, so there was little pressure to enact any common sense standards or introduce infrastructure to solve the problems of the populace. This system is the reason that these problems persisted for so long instead of being solved."
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3oiyqu | so gravity warps space time... but why does that mean i keep falling back to earth? | Basically explained gravity and its relation to its effect on me and space time. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/3oiyqu/eli5_so_gravity_warps_space_time_but_why_does/ | {
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"Imagine a sheet that's stretched out taught. That's spacetime. Put a bowling ball on it. It warps the sheet much like a massive object warps spacetime. Now, put a golf ball on the sheet, and see how it's \"drawn\" to the bowling ball. That's gravity as caused by the warping of spacetime."
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5hcy6b | why does our solar system spin on nearly a 2 dimensional plain? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5hcy6b/eli5_why_does_our_solar_system_spin_on_nearly_a_2/ | {
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"Its like a pizza dough. As it gets spun it forces itself into a disk. Samething with the solar system. The force of rotation causes it to spread out",
"When anything spins it does so on an axis, and all movement happens in the plane perpendicular to that axis. Think of a bike wheel: no matter which direction you hold the axle, the wheel itself will always spin at right angles to it.\n\nThe solar system formed from materials moving and coalescing in the same way - everything roughly spinning around a common axis. As larger chunks formed, anything rotating in a different plane would tend to be swallowed up by the larger pieces.",
"The material that made up the early solar system collapsed inward from a cloud of gas and dust that had a small amount of rotation. Anything that was moving against that rotation, or perpendicular to it, collided with something else and was knocked away from its original path.\n\nIt's like trying to walk crosswise through a crowd of moving people: you're going to bump into everyone until you decide to go with the flow.",
"It has to do with angular momentum. I'm just going to walk through a thought experiment, that's my disclaimer (although many people on reddit seem overly eager to state things they are unsure of as fact... I'm not going to do that to you. I'm not 100% sure about what I'm talking about. But I'll lead you towards the difficult n-body problem you are asking about). The simplest way is to say \"it's like a [bike tire](_URL_0_)\" but that doesn't do the question justice. Angular momentum is found using the right hand rule convention. It is expressed as a vector.\n\nSo imagine you have a binary star system, just 2 objects orbitting a common barycenter. Obviously these 2 objects are going to be in the same plane of orbit, because where's the gravitational force that is perpendicular to the plane going to come from? Put 2 coins on a desk, and think about it. If the only force acting on the coins were gravity between them, then they wouldn't be able to go above (or below) the table.\n\nNow imagine 3 objects in space. Well, actually it's very hard to haha. If those 3 objects were MOVING in a plane, then they'd stay in the plane because there's no gravitational force component perpendicular to the plane. These 3 objects would have a common center of mass however. And as they danced around the 2d plane, the center of mass may move. I can't predict what would happen here without simulating it.\n\nNow imagine 3 objects in space with velocity vectors in 3 dimensions, instead of just in a plane. Harder again to imagine. But they would have a common center of mass, and as time progressed, they would move, and so would their common center of mass.\n\nNow imagine billions of particles in space with velocity vectors in 3 dimensions. Now we are getting into what I presume would be some very basic universe simulator.\n\nAnd it turns out that, the only **stable** configuration, is everything having the same angular momentum around a common center of mass. Clearly if you look at our solar system, the result is a giant massive thing in the center and everything orbitting the same way around it. EVERY particle in this mess of random particles with random velocities tended towards obtaining the same angular momentum vector. Which is another way of saying each planet orbits in the same clockwise (or counterclockwise, depending where you look at it from) direction around the sun in the same orbital plane.",
"I know it's against the rules here, but [this video from minutephysics](_URL_0_) is so good I don't think I can add anything useful to it.\n\n"
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3aswxm | why do stores post "shoplifters will be prosecuted" signs? | I mean, obviously stealing is illegal and everyone knows it so why do stores post it? Is there any legal benefit for them? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/3aswxm/eli5_why_do_stores_post_shoplifters_will_be/ | {
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"So shoplifters know there is no tolerance for that kind of stuff. Maybe? ",
"Scare tactic, most people don't know stores rarely prosecute for theft because of the expenses associated with going to court. So the stores are taking advantage of customers' who don't know that and use the scare tactic to scare someone from stealing. ",
"Some stores will be lenient if they catch you, they'll say \"put it back on the shelf and get out of here.\" Others won't want to go to court, it's expensive and time-consuming, and not worth the effort for petty shoplifting. But some stores will go through the effort of prosecuting, and it's a powerful threat. "
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2mo948 | random rushing feeling while in bed late at night | Randomly, when I'm laying down in bed late at night, and I randomly feel this really weird, almost indescribable feeling in my head that can only be described as a "rushing" feeling. Which is accompanied by a sound that, like the feeling, can only be described as a "rushing" sound. I'm wondering what exactly this is and what is causing it.
EDIT 1: This also happens as I'm about to fall asleep. As I'm drifting off, I feel like I'm falling and hear a sound. I think it may be something called "Exploding Head Syndrome" | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2mo948/eli5_random_rushing_feeling_while_in_bed_late_at/ | {
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"I get this too. Usually when i'm about to lose consciousness. The rush feeling I kinda get, but more than often its a rumbling feeling (almost like a very strong earthquake) and my bed begins to vibrate very intensely. ",
"If ever I'm sick, I have a very distinct \"dream\" consisting of an environment composed entirely of tv static and a single potato like object being stabbed repeatedly by a sewing needle. It's been like this for as long as I can remember. It's terrifying. "
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2fzug2 | is there any virus which infects apple products?why is there such a big problem with windows and hardly any problem with the mac when it comes to bugs? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2fzug2/eli5is_there_any_virus_which_infects_apple/ | {
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"Yes, there has been malware for Apple products including OSX. Windows gets targeted more because it has a far larger market share. I haven't had significantly more bugs on a Windows device than I have on OSX. I haven't seen a BSoD since XP was the latest Windows OS, but I did see a kernel panic on OSX (So basically the equivalent) just a few months ago.",
"The myth that Macs are immune to viruses has been circulating the Internet for as long as there has been an Internet.\n\nFor what it's worth, there is a list of Apple Macintosh viruses from Mac Digest. It is dated **Thu, 11 May 1989**.\n",
"People ask this a lot. I wrote this 3 days ago\n\n\nWindows operating systems make up roughly over 90% of desktop and laptop usage. Osx in contrast makes up less than 7%. \n\nNow, imagine you are a cyber criminal who's intention is to infect as many computers as possible to steal information/money/etc. Which operating system should you code a virus for? Which is more worth your time? Windows, obviously, because it dominates in market share.\n\nApple has people fooled that they intentionally make their computers virus proof, when that's simply not the case at all"
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1dgzjj | esperanto and other conlangs | Looks like this hasn't been posted before, so here's a new topic for discussion.
What's the deal with Esperanto?
- Why should I be interested in it?
- Is it a useful thing to learn?
- Will it make it easier for me to learn other languages?
- What is its relationship with other conlangs, such as Ido, Novial, etc?
- How is a conlang like Esperanto different from a "logical language" like Lobjan?
- In a single sentence, why is Esperanto cool?
I would love to get more insight into this! | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1dgzjj/eli5_esperanto_and_other_conlangs/ | {
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"Esperanto is cool mostly because it was created as a way to try and close communication gaps. It sounds like you already know a lot of the background behind its creation. I like the idea of it, but it isn't practical. I wouldn't bother learning it for anything other than novelty or linguistic studies. It's more of an important thing to learn about than to learn.\n\nI don't really know much about Lobjan, but it seems the main difference is that Lobjan tries to use a latin base and follow logical rules of syntax, whereas Esperanto tries to meld linguistic rules from many languages and root languages.\n\n.\n\nI am pretty far from a linguist, but I thought this post was very interesting. It makes me want to go back and learn the history behind some other conlangs/",
"Esperanto is cool because since I learned it, I traveled to several countries and met a ton of interesting people.\n\nYou can ask /r/Esperanto if you want to know more about it.\n\nEdit: you can also read [this AMA](_URL_0_)."
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3hxlrq | what did hillary do wrong? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/3hxlrq/eli5_what_did_hillary_do_wrong/ | {
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"Legally, at this point it *appears* that sensitive and/or classified data *may have* been stored/sent/received on her server. \n\n**Whether or not:**\n\n* 1) it was unclassified when it was sent\n* 2) the use of a private email was not forbidden\n* 3) there were adequate security controls on the server\n* 4) She had any knowledge of, or control over every single email and all data\n* 5) None of this was intentional, it was all accidental, and some or all was done by her staff without her knowledge or consent.\n\nAll of the above may or may not have broken rules or laws, but the bottom line is **it does not matter**\n\n* This issue has distracted and drowned out any campaign messages or talking points.\n* She has done a terrible job dealing with the media on this issue. \n* She needs to go on the offensive, disclose everything, control the message. \n* Now the media and investigators are letting the message drip, drip, drip out.\n* She has adopted a very lawyer-like strategy: while shrewd legal strategies may win lawsuits or avoid prosecution, they do not win the hearts and minds of voters.\n* Overall this is the perfect storm for her opponents to paint her as not being trustworthy, and her overall strategy and message is not one that does anything to change that picture one bit.\n\n**This is like a slow-motion train wreck, with more train cars showing up and crashing each day, one day at a time. Her message has been \"There is no train, and anyway, the train, if it does exist, was on the tracks when I was driving, and oh yeah, now the train cars are all empty, so no worries.....\"** [crash]\n\ntldr; Biden/Warren 2016",
"[Slate did a great article on this](_URL_0_)\n\nTl;Dr : Hillary had a personal email server created at the same time she started work as the Secretary of State. While use of a personal email is not forbidden, the sending of classified or top secret information via a personal email server IS illegal. Investigators have indicated that she did send classified and top secret information via the personal server. "
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y9boj | venture capitals. | How do they work? How do they formulate/start? How did the idea originally started? Although I'm an educated guy but I know nothing about business, so keep it simple please. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/y9boj/eli5_venture_capitals/ | {
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"A venture capital firm is a company that invests in other companies. They usually are only interested in startup companies that have the potential for massive growth. A lot of them focus on high tech or biotechnology companies.\n\nHowever, they don't just go and buy stock in other companies like a mutual fund does - when they invest they want an active role in participating in the companies' management. Typically a venture capital firm that invests in a company will buy a 30-40% interest in that company and get represented on the board of directors. Many companies welcome that - a startup company that has five engineers in a garage probably doesn't have the business skill to really know how to grow their business to another level, or how to really profit from their invention, so that's where the venture capitalist's business skill is valuable to the company.\n\nVenture capitalists expect that most of the companies they invest in will fail, but all you need is to find one company that becomes the next google or facebook, and it will more than pay off for all of the ones that didn't work out.\n\nIt's different than private equity, since a private equity firm will normally buy out an entire company - instead of just taking a share of it and participating in the management."
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1ym0jx | why do we have so many distinct bird varieties, when most birds can cross breed with each other. | Birds do cross bread in captivity. and in the wild I know many birds are specialists who may not meet, etc, so I'm not really asking about kingfishers and eagles etc.... but there's many varieties of tits, finches, bramblings etc. that actually flock together, yet remain as distinct species instead of mixing. Why does this happen? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1ym0jx/eli5_why_do_we_have_so_many_distinct_bird/ | {
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"Most bird species cannot crossbreed just like most mammal species cannot. Different plumages and subspecies can crossbreed but not different species.\n\nCaveat: Species is a human term not something that is strictly followed in nature. For example, glaucus-winged and western gulls can (and do) crossbreed despite us calling them different species. There are not many species that can do this however."
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21ci9m | why do blind people not see black? isn't blackness a lack of stimuli to the visual processing center of the brain? | I see this brought up frequently in threads such as this one: _URL_0_
But I don't see how that can be accurate. Blackness, to me, simply indicates no stimulation of the optical nerve; there are no photons hitting your retina at the location you perceive as black. As such, when you close your eyes in perfect darkness (to prevent outside stimuli from penetrating your eyelids) would this not be exactly what a blind person sees?
In both scenarios neither person involved is having the area of the brain responsible for visual stimulation activated. What differentiates this from "blackness" that we perceive from being in pitch dark? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/21ci9m/eli5_why_do_blind_people_not_see_black_isnt/ | {
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"It would depend on the nature of the blindness. If your eyes are still sending info the brain but not seeing anything then sure maybe it is nothing but black.\n\nBut the hard thing to understand is the idea that no info is flowing from the eyes to the brain, as such there is nothing not even black. Black is not the absence of information, its your eye telling your brain \"I cant see shit!\" so its different then just no communication at all. \n\nThe best way I have had this put is try to imagine seeing out the back of your head. You can't because at no point have you ever had that information going to your brain. ",
"Some do just see black. If you've previously had vision and then gone blind later in life, the lack of stimili would result in \"black\".\n\nWhen someone is born blind they've never utilized any sort of vision their brain has nothing to judge what black is. All colour is just our brains intrepetation of different wavelengths of light.\n\nImagine this... sharks have the ability to sense electromagnetic fields. I want you to try and sense these fields. What you're doing now is what a blind-from-death person would be doing. Trying to use a sense they don't have.",
"Some birds can sense magnetic lines of force from the Earth, allowing them to migrate during the winter and return in the spring. If they were capable of speech, they'd probably have all manner of words and terms for the sensation of feeling these magnetic forces -- whether they were strong or weak, what direction they are, and so on. They'd probably also have a term for when they can't detect any magnetic field, for whatever reason -- their equivalent to blindness.\n\nNow, go ahead and try to detect magnetic waves. Do you feel a \"blackness\" in that area? Or is the entire notion such a foreign concept that there's no magnetic blackness at all, the concept doesn't even apply since there's nothing to compare it to? That is, you've never in your life been able to detect magnetic forces, so have you always been consciously aware of a black void in that area, or has it never even occurred to you before just now? ",
"Tommy Edison has a great channel on youtube where he explains things like this. He is blind since birth.\n\n[What do blind people see?](_URL_0_)",
"If you have a functioning hand, you can feel all sorts of textures. All the textures are available. \nIf you put that hand in a glove, the only texture you can feel is the one inside the glove. Only the glove texture is available. \nIf you cut off your hand, you don't feel anything with your hand. No textures are available, including the one with a gloved hand. ",
"The best I've heard it: close both eyes, you see black. Close one eye and try to \"see\" out of it. You just have no perception. Now imagine that but with both eyes.",
"For the same reason you don't feel air. Your brain ignores that which it can safely predict, and a sightless person (gotta be careful with \"blind,\" which covers a variety of conditions) is completely tuning out their visual sense, either because it's gone or they never developed it.\n\n(Yes, you feel wind, but you don't feel the 14+ pounds/sq inch of pressure that's pushing on the entire surface of your skin-- you feel the variation, but not the constant.)"
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8o6qzw | why does hiv turn into aids? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/8o6qzw/eli5_why_does_hiv_turn_into_aids/ | {
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"HIV is a virus which attacks the immune system. AIDS, or \"acquired immune deficiency syndrome\" is when the immune system isn't able to do what it is supposed to. HIV attacking the immune system will tend to reduce its effectiveness, the state of which is called \"AIDS\".",
"As the HIV cells disarm your white blood cells (your magic protectors) your body is unable to defend itself against all sorts of gross stuff. This condition is called AIDS.",
"HIV infects specific white blood cells called CD4+ T-lymphocytes. These are responsible for controlling your body's immune system and regulating it. Without enough of them, your become immunodeficient. They act like commanders and tell other white blood cells what to do when the body is under attack\n\nWhen you first get infected, there's a mild symptomatic (like a mild flu) period, then it stops for a long time. During this, your white cell count decreases slowly over time. Once it decreases under a certain threshold (400/ml), your body can't handle infections anymore and you become overwhelmed by rare diseases that typically hit immunodeficient people. Hence: Acquired (from HIV), Immunodeficiency (deficient immune system; white blood cells in this), syndrome",
"Important terminology note: HIV is the name of the virus, AIDS is the name of a syndrome that can be induced if the virus is not controlled.\n\nTo replicate, HIV invades a type of immune system cell in the bloodstream, which also results in the death of those cells. As a result, the immune system is significantly weakened if the virus is not brought under control.",
"HI*V* = Virus\nAID*S* = Syndrome\n\nSo a person can contract the Human Immunodefiecirncy Virus, but not have AIDS. AIDS is a syndrome; or a combination of factors from various body systems breaking down due to complications from the HIV Virus.\n\nExample, you contract HIV. Over time, among many other illnesses, you succumb to pneumonia. The rest of your bodily systems have also been weakened from complications of the Virus. So you can't fight off pneumonia and you perish.\n\nThe virus itself didnt kill you. The virus causd various problems in you body - an Auto Immune Deficieny Syndrome.",
"HIV doesn't \"turn into AIDS,\" any more than a carpenter becomes a cabinet. HIV attacks the immune system, keeping it from working properly. \"AutoImmune Deficiency Syndrome\" was the name given when we noticed people's immune systems weren't working properly not knowing the cause. Later we found it was a particular virus, which was named Human Immunodeficiency Virus.\n\nHIV can be treated (not cured) by keeping the virus from reproducing, whereas it already has in AIDS and so the focus is on preventing secondary infections you and I may be able to fight off easily but could be fatal to an AIDS patient."
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3kg7qg | how someone can write a pc virus without it infecting their computer? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/3kg7qg/eli5_how_someone_can_write_a_pc_virus_without_it/ | {
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"Because they aren't stupid enough to execute it on their machine. \n\nSometimes they will infect a junk machine at first to start the infection. ",
"Virtual machines. There are plenty of tools out there that allow you to emulate a PC ina software vitual machine. If the virtual PC gives up and dies because of the malcious code you have written you just close the virtual machine down and you're back in your regular PC. \n\nVMs are used for many things like testing new software on different OSs and so on. "
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13vwbo | reformatting a hard drive? | How does it erase the information so much quicker then just deleting it?
What is actually going on when you reformat it? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/13vwbo/eli5_reformatting_a_hard_drive/ | {
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"So, your hard drive stores data as a series of 1's and 0's. So, what does it mean to delete something? Well, you could just set all of the bits to 0. That would effectively delete it. But, as you noted, that would take a long time for the entire hard drive because you'd have to touch every single bit on the disk and set it to 0.\n\nIt turns out there's an easier way. At the beginning of the disk is a special file called the file allocation table. This is a list of all of the files on the disk and where they are located. So, you might have \"resume.doc\" and it starts at bit 8,547,980 and takes up 100,000 bits. That data is stored in the FAT. When Windows wants to find resume.doc it looks up where it is stored in the FAT and then goes to that location on the hard drive.\n\nIf you wipe out the FAT then the location of all of your files goes missing. The table is now empty and every bit is considered available for use. The files are still technically there, but your computer doesn't know where to find them. If you're not too concerned about security this is a very fast way to delete all files on your hard drive."
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2etw8c | what speed should i be driving in order to preserve the most gas? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2etw8c/eli5_what_speed_should_i_be_driving_in_order_to/ | {
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"There isn't just one answer. It depends on a lot of things from the horsepower output of your car, the weight, your drag coefficient, your transmission gearing, and so on. What kind of car do you drive?",
"It varies from car to car based on things like friction of the tires on the road and drag and things like that, but for most cars it is around 40-60 mph.\n\n[More details](_URL_0_)",
"Zero mph would use the least gas, zero if the engine were turned off.\n\nFor actual *driving* it's around 50-60 MPH. 55 was chosen in the 1970s as the US National Speed Limit (it isn't any longer) because it was right around the average maximum fuel efficiency for all vehicles."
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13dxt8 | eli: _url_0_ | Seriously, what the hell is it? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/13dxt8/eli_quibidscom/ | {
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"It's a bidding site which offers quite low prices, but there's a hitch. You have to pay for the right to make each bid (about 60 cents, I believe). That's *per bid* and you're paying whether you win or lose.\n\nAlso, that money for buying the right to make each bid is separate from the price of the item itself, should you win.\n\nSlate had a write-up on a similar site called _URL_2_, calling it, \"the evil bastard child of game theory and behavioral economics\": [The Crack Cocaine of Auction Sites](_URL_0_)\n\nHere's an article more specifically on Quibids: [A Deeper Look at Quibids … and Why I Don’t Think It’s Worth It](_URL_1_)",
"Okay so basically it's exactly like ebay but when you pay for a bid, it costs .25. What that means is that each person who bids helps pay for the difference in sale price. So after a set amount of bids, everybody pays for the item until the final person buys it. Either way you wasted money. If not enough people bid, a bot will raise the price again."
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svcw1 | the relationship between passing laws and court rulings | I'm always confused by how these two affect each other. Just to use one example: The California Supreme Court ruled that gay marriage should be allowed, but then California passed a law prohibiting it. Why can they pass a law that the court already said isn't permissible? Could the court rule **again** that it's unconstitutional, and then knock down the law all over again? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/svcw1/eli5_the_relationship_between_passing_laws_and/ | {
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"They could, but the general way it gets resolved is to move the question to a higher court. \n \nIn the US, the legislative, judicial, and executive branches have equal power, but different roles. The Constitution is supposed to be the ultimate authority. Laws passed by the legislative branches must not contradict the Constitution, and the judicial branch gets to decide if they do or not. The judicial branch doesn't get to decide on their own if a law is \"good\" or not; that's up to the legislative branch. \n \nThings can go back and forth a bit, but usually they won't do it too much. If a court has ruled that a law is unconstitutional, then the legislature must change it or give up on it, or the executive branch won't enforce it. If they do change it, they generally try to avoid the problem that the court pointed out in the first place, otherwise it's just a waste of everyone's time and it won't be enforced. \n \nWhen a law is very controversial, it will often be ruled upon by multiple, ever \"higher\" courts. If a court rules a law is unconstitutional, then it can often be appealed to a higher court. This can go on for several steps, with the Supreme Court of the United States being the last one. If they rule that a law is not constitutional, then it can't be enforced without being changed. If it gets changed, but a court rules that it still has the same problem as before, it can't be enforced unless it goes up the chain again and some court rules that it IS constitutional. "
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bd22qn | when you cross two beams of light, e.g. from flashlights, why are they not interfering with each other at all? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/bd22qn/eli5_when_you_cross_two_beams_of_light_eg_from/ | {
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"***TL;DR:*** *Because light isn't really a physical beam so much as a group of little packets of energy that don't interact with each other.*\n\nImagine you and a friend are standing on a 10 foot wide diagram of a clock, with you at 6 and them at 3, both facing the middle. You both grab a handful of fine but very heavy sand. At a count of three, you both fling and spray your sand toward the centre... and the two clouds of sand pretty much pass through each other. There might be a collision or two that knocks a few grains of sand out of their path, but almost all of the sand would go through cleanly and end up at the other side of the clock.\n\nLight is *a little* like that sand, except the photons (really, little packets of energy) are INCREDIBLY small and moving INCREDIBLY fast. So the odds that two particles are going to impact each other are almost impossibly slim. So the light in general goes through rather than be impacted by a collision.\n\nBut where the sand analogy fails is that light 'particles' don't really \"collide\" or interact anyway, not unless they're under very special circumstances. You can have one photon \"touching\" another and it doesn't really do anything to either. So off they go, not changing direction or anything, until they eventually blind a deer or annoy a light-sleeping neighbor.\n\n{**edit** to include a second analogy for two photons intersecting}\n\nToss two pebbles into a calm pond at the same time, about two feet apart, and watch the ripples. You'll see they intersect and touch, but afterward just keep on going. Those two waves don't really CHANGE each other - their direction and speed remains exactly as it was *before* they hit as it does afterward. Same with photons - they'd just pass right through each other and keep going, unchanged from previous.",
"For photons (light particles) to interfere with each other, they have to be 'coherent'. This means they have to travel in the exact same direction. \nTo crossing flashlight beams do not fulfil that requirement. Read more on coherence on wikipedia, if you are interested _URL_0_",
"How do you know they aren't? What would interference look like in this situation?\n\nThe light in a flashlight beam is all jumbled up. At the smallest level, the two beams will interfere with each other (as well as with themselves). But the result of this interference is still two beams, still being all jumbled up, just jumbled up in a slightly different way. This makes no noticeable difference at the scale where your vision operates.",
"The word \"interference\" is misleading: when linear waves interfere, the individual beams are *not* affected by each other: they pass right through each other. This is true for light, sound, ocean waves, whatever.\n\nWhat *is* affected is the sum of the two waves: the sum of a crest and a trough can cause the total wave strength (height/pressure/electric field) to be zero in certain places, but that does *not* make the individual waves disappear: they continue right on through the zero point.\n\nYou can see these destructive interference points with a laser, but not with white light from a flashlight. Their location depends on the source location of the beams and their wavelength. White light from a flashlight has a spread-out source and a wide range of wavelengths, so there's no place where *all* the light destructively interferes.\n\nBut as explained above, even two crossed laser beams will pass right on through each other.",
"The thing is, they ARE interfering with each other - you just aren't seeing it. If you had a special (and very sensitive) camera that let you look at a nanosecond (or less) exposure of two flashlights overlapping, you would see an interference pattern from the two light sources. But... since those light sources are emitting light in a more-or-less random pattern, the next nanosecond you would see a DIFFERENT interference pattern. And the next nanosecond you would see yet another interference pattern. So, as your eye integrates all of this light over 1/30th of a second or so, it doesn't see those individual interference patterns, but rather millions/billions of them all on top of each other, which leads to a smooth overlap of light beams.\n\nLasers are different, because laser sources are coherent. This means that the laser light is not random... think of incoherent light as a bunch of people walking randomly through a city, and coherent light as a marching band, or marching soldiers. This interference pattern from a coherent light source stays in the same place, so when your eye integrates it, it sees the pattern."
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3fq0am | what is an os made of? how does it work too? | Like Microsoft Windows or Apple iOS etc; isn't it like an onion or tortoise where the outer layer or shell is the display amalgamation of compiled and structured information comprised of 0's and 1's? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/3fq0am/eli5_what_is_an_os_made_of_how_does_it_work_too/ | {
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"text": [
"You are correct in that there are various layers. Let's go into a bit more detail:\n\nThe **hardware** is the physical circuits of a computer; the circuit boards, chips, etc.\n\nThe **software** is all of the programs that run on your hardware. It's stored in your computer's memory as a sequence of 1's and 0's that your computer can interpret.\n\nThere are different types of software. The **operating system (OS)** is the software that provides the basic framework for your computer to run. It's most basic function is to translate all the 1's and 0's into something you can understand and then display it on the screen. There are various types of operating systems, but usually, your computer will only run one OS. (You can change your OS, but it requires some technical knowledge.) Examples of OS's are Windows, OSX, iOS, Linux, etc.\n\nFinally, you can run various **applications** such as MS Word, Google Chrome, Minecraft, and Mail (among many, many others). These applications use the OS as a framework to run, and are generally the whole point of using a computer.\n\nTo summarize:\n\nYou use various\n\n**Applications** which run on your\n\n**Operating System** which runs on your\n\n**Hardware**\n\nHope that was helpful!"
]
} | [] | [] | [
[]
] |
|
3d5z8f | what is a technocrat? | And why are they bad? (or so I hear) | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/3d5z8f/eli5_what_is_a_technocrat/ | {
"a_id": [
"ct23ml3"
],
"score": [
3
],
"text": [
"A technocracy is a system of government where leaders are selected based on their knowledge of technology. A technocracy would be run by scientists and engineers instead of lawyers and businesspeople.\n\nA common criticism of this form of government is that technocrats have less understanding of people than lawyers or businesspeople, which would be very harmful for a leader that has to persuade others to accept their idea, consider the consequences of their actions everyone living in their country, and communicate effectively with their citizens."
]
} | [] | [] | [
[]
] |
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