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7ccxrs | Why do phones sound so much worse when on speaker? | Technology | explainlikeimfive | {
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"The energy in a sound signal dies off pretty fast the farther away you get from it. This is fine for really small speakers that you put *very* close to your ears like headphones, earbuds, and telephone speakers. When you switch to \"speaker\" mode on a phone the speakers used are still very small and the power dies off pretty fast, unfortunately not all the frequencies die off at the same distance so the sound gets distorted."
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7ccyrh | Why do humans get viruses that present with a sore throat, cough and runny/stuffy nose, but animals don’t (appear to) get these same viruses and/or symptoms? | Biology | explainlikeimfive | {
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"A certain kind of virus that affects humans makes your throat sore so that you'll cough, in turn so that you'll spray a fine mist of virus-water into the air to infect other people. This is an effective strategy for the virus, because people spend a lot of time together (and not just with one closed social group), and the virus can spread broadly. Because it's an effective strategy, there are lots of viruses that do it. But many other animals have much less social habits. Making those animals cough isn't as likely to infect new hosts as it is with humans. So there are fewer virus species that employ the same strategy.",
"Runny nose, cough, fever, chills and others are not caused by the virus directly, these are responses by your body attempting to make the body intolerable for the virus or to flush it out. just like dogs regulate temperature by panting, whereas humans regulate temperature by sweating. the virus itself is not the cause... it is the immune system of the host",
"> but animals don’t (appear to) get these same viruses and/or symptoms? There are plenty of diseases that only affect certain species. But animals can't talk to complain about their sore throat, so it's harder to tell from an observer's perspective. They do have similar symptoms, though! One sign of illness in many animals is a runny nose, or seeing them breathe through their mouth (possibly in gasps, as they struggle for air in cases of pneumonia). Prey animals are thought to have evolved not to show very obvious signs of disease, because predators look for sick animals for an easy kill. In particular, I have read that snakes will show very obvious symptoms early on when they start to get sick, but with small tortoises (which are not high on the food chain) you may not notice any outward signs until the tortoise is already pretty sick."
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7cd3r1 | How does MSG make food taste “better”? | Biology | explainlikeimfive | {
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"We have five senses of taste, specific receptors in our mouth that are responsive to chemical properties in food. All of them have important survival properties. Sweet, the presence of easy sugary calories, tells us, \"This fruit is ripe!\" Sour, the presence of acids in food that tells us, \"This fruit is *not* ripe, yet\" Salt, really simple one here, we just can't live without an adequate intake of the stuff. Bitter, it serves as a warning that \"This stuff might be poisonous!\" This is a complicated one. Chocolate, the tannins in red wine, the tannins in coffee and tea, are all fundamentally bitter tasting but in moderate intensity, we can find them quite pleasing and they are obviously not toxic. large numbers of compounds whose name end in the suffix \"ine\", [morphine]( URL_0 ), [strychnine]( URL_1 ), [coniine]( URL_2 ) are quite toxic and they are all bitter. \"Umami\" is the Japanese word for \"savory.\" This is the most complicated and recent sense of taste in humans to be recognized *by western science.* The Japanese have known about this taste for some time but it's only been in recent decades that our science has identified the receptors and the compound to which they are sensitive. It's is a naturally occurring amino acid, a component of proteins, called glutamic acid, an often used salt of that acid, monosodium glutamate is commonly known as MSG. When MSG was first marketed in the US it was labeled as a \"flavor enhancer\" which is a gross misstatement of its actual function in food. It's not an enhancer at all in is a flavor *in its own right.* The survival value of our taste for Umami is that it is a marker for the presence of quality protein in food, especially proteins which have been broken down for easier digesting by the process of cooking. If you lick some raw soup bones they don't taste so great. After three hours simmering in some mildly acidic water with some aromatic vegetables, the broth is some of the best of \"comfort foods.\" MSG has no place in candies. Pick up a food package with \"No Added MSG\" on the label and check the ingredients list you'll often find \"hydrolyzed vegetable protein\" there. No, they didn't add any pure crystalline MSG, they used the HVP which is loaded with the stuff. Used poorly, Umami can be offensive, as a *tiny* taste of pure MSG will amply prove. Used well and in proper balance with our other senses of taste, it is a delicious, harmless, and powerful tool for a cook to work with. Edit; minor formatting and spelling."
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7cd3uq | if red, green, or blue lights allow for better "night vision" why are car headlights not made in green or blue to preserve night sight? | It makes sense not to use red but why not use green or blue tinted lights as headlights rather than what we use? | Technology | explainlikeimfive | {
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"To give a simpler explanation that fits ELI5 better (the others are good so far mind you) Things look different under different lights. We see \"white\" light all day, every day. If our headlights were red, blue, green or any other color really it makes it much harder to see and understand what you are looking at because we are not used to it and our eyes are trained to see things best under white lights. If you grew up using red/blue/green lights every day for everything maybe you could do that and it would be easy for you, but that does not work for the masses.",
"Because car lights aren't designed for the oncoming traffic, but for the driver of the car. What I wonder is why they haven't made some sort of divider that reflected / blocked the lights so the oncoming traffic didn't have to stare into the lights? Maybe something as simple as a slight polarity in the windshields so light from the left is slightly blocked? I dunno. .. something.",
"Red is better for night vision, blue and green would be terrible! Blue light is what you want to avoid when trying to see in low light. Having red headlights would enable you to see in the dark quicker after looking into them, but you wouldn't be able to see nearly as well with them. Under red illumination everything would look weird to you and you wouldn't be able to see a far distance effectively",
"It has to do with how different wavelengths of light react to their environment. For example, if you are an auto-sport fan, you might have noticed that many race cars use yellow fog lamps. This is because yellow light is much better at penetrating water vapor than white light, and therefore performs better in fog or rain. Yellow light also produces much less glare. Blue or red lights would have a very hard time cutting through mist or fog. Humans see much, much better in white light than in any other color. White light appears to our eyes to travel farther than colored light. If you've ever been in a situation in which red, blue, or green lights are used for vision, like night orienteering or a night flying aircraft, you will notice that it is much more difficult to see with colored light than with a normal flashlight. Colored lights would also change the color of the objects you are seeing, potentially causing some confusing situations. Most modern cars use a Xenon discharge lamp that tends to be towards the blue spectrum. These lamps are very carefully aligned so that they cause as little blinding as possible to other drivers. These lamps are great at illuminating a wide cone in front of the vehicle for a long distance. Colored lights would have to be very, very intense to achieve the same perceived effect."
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7cd8dj | Why caller ID allowed spoofing when it was first created? | Technology | explainlikeimfive | {
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"It was for law enforcement. It is pretty easy to figure out which numbers are coming from a law enforcement agency, so caller ID would make it harder for them certain things, like undercover work. Law enforcement pressured telecoms to allow spoofing because think of the children, so it became a thing. Since there are so many telecoms and wireless and VOIP services were rapidly evolving, the technology was not particularly robust, and telemarketers and collection agencies soon figured out how to do it. Nothing said it was specifically illegal, and you don't get a lot of campaign contributions for siding with consumers against corporations, so the current laws are weak. They and subsequent court rulings say spoofing is only illegal if there is an intent to defraud, which is certain to deter fraudsters from committing additional crime."
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7cdbep | How are there so many million dollar homes in California if the median income is only about $70K? | Economics | explainlikeimfive | {
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"Because most people in the area aren't selling their houses, but a lot of people want to buy. If there's more people willing to spend a million dollars on a house than there are houses for sale, then you end up with a ton of houses worth a million dollars and a lot of people who can't afford to buy a house.",
"It's a complicated topic and I'm no economist, but there are certainly a few factors at play here that I'm aware of. Real estate is usually a safe investment. Back when the Great Recession hit, national banks dropped their prime lending rates to encourage investment in capital. People chose to invest in real estate, and they started buying homes they previously couldn't afford. A lot of people also began basing affordability on dual incomes, as opposed to a single income as they did in the past. As urban areas began to gentrify, this pushed up their property values. Meanwhile, developers have been unable to build fast enough to meet the huge surge in demand. Speculators also began jumping in on the market. A lot of foreigners have been buying up investment properties in Canada and the USA. The Chinese are best known for this practice, particularly on the West Coast. The PRC government limits how much they can invest through traditional channels. So it's led to real estate being commodified over there, which has spilled over to other countries where wealthy Chinese do business. A similar phenomenon has been seen on the East Coast with Indian and Arab investors, largely for the same reasons. The thing with these investment properties is they're actually worth more completely empty. They can be converted back into liquid assets (cash) more quickly than an occupied unit. But it's exacerbating the supply problem by creating artificial shortages. You still have this huge demand for people who want homes to actually live in, but a lot of choice units are owned and just sitting vacant. Again causing prices to rise.",
"It should but it doesn't. Australia is the same. I'll never be able to afford a house here.",
"Part of the problem in California specifically is that the cost of building new properties is *astronomical*. Due to worries about gentrification or ruining the \"culture\" of areas, getting permission to make new buildings can be extremely draconian, taking months just to get permission to build, so the existing properties are becoming more and more valuable because getting new ones is so cost-prohibitive. I've spent like a half hour trying to find this really in depth article I read, but haven't had any luck, sorry."
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7cddo1 | Can diodes be made to emit X-Rays and Gamma Rays just like they emit light in LED's? | I am asking about semiconductor devices here. | Physics | explainlikeimfive | {
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"I don't believe so. An LED emits a specific color of light that is due to the \"band gap\" of the semiconductor materials it is made up of. This is basically the energy difference between electrons in the valence band and conduction band. By careful engineering of the semiconducors, it is possible to get various colors of LED. X-rays and gamma rays are significantly higher energy (shorter frequency) than visible light. It seems unlikely to me that you could engineer the material to have such a large band gap.",
"X-Ray, yes. A standard X-Ray tube is simply a vacuum tube with a tungsten anode and cathode at each end. An electron stream is directed through the vacuum and the resulting collisions produce a little bit of X-rays and a whole lot of heat. Gamma ray, no. Gamma rays are produced during radioactive decay, but other than that, gamma rays require an immense amount of energy to create. They only exist on Earth from a non-radioactive source as a result of lightning strikes or cosmic rays. CERN can probably make them, but I've never heard of any being produced in a lab outside a particle accelerator."
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7cddr0 | How soap is both hydrophobic and hydrophilic at the same time without one taking over | Chemistry | explainlikeimfive | {
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"Soap is an emulsifier. One end of the molecule is hydrophilic and the other end is hydrophobic. One can't \"take over\" the other unless there is way more oil than water or vice versa."
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7cddyl | Why do bass sounds seem to travel better through walls, when high pitched sounds usually carry better over distance? | I have always had the impression that high pitched sounds carry better - for example a high pitched voice is often understandable from several rooms away while a bass voice often doesn't seem to carry. My personal experience is that often my girlfriend cannot hear me from the next room unless I deliberately speak in a falsetto, whereas I can always hear her. I have read before that women and children have higher pitched voices so if they get in trouble with a predator and scream, the males will hear them more easily and be able to come to the rescue. Screams by nature tend to be in a higher pitch than normal, presumably because higher pitches carry better over distance. But when it comes to certain bass sounds, like those created by car stereos and subwoofers, it seems they can carry through walls and be felt while the higher pitched sounds drop out. Often when driving I can feel somebody's bass from their car stereo while hearing no other elements from the music. Since I live in an apartment I am wondering what is more likely to annoy my neighbors: the high pitched chirping of my pet birds, or the pounding bass of my sound bar subwoofer when I watch an action movie. | Physics | explainlikeimfive | {
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"There are two effects at work. The first is the physics of it. Any material will attenuate different frequencies at differing levels. For most solid materials, low frequencies will be slightly attenuated and high frequencies massively attenuated. Through free space, both attenuate over distance but by relatively similar amounts (high frequencies still don't travel as far, but low frequencies don't have the huge advantage they do passing through solid materials). This relationship is not strictly linear, but generally low frequencies penetrate/propagate better than high ones. The second is the biology of it. Human beings hear high frequencies (relative to our range) significantly better than we hear low frequencies. What we think of as 'balanced' levels across the frequencies are actually incredibly loud low frequencies coupled with relatively quiet high frequencies. When you evenly attenuate across the frequency spectrum, this causes low frequencies to drop into the inaudible range much more quickly than high frequencies. The combination of these two effects is what causes the phenomenon you're experiencing. If you've got a wall, low frequencies punch right through while high frequencies are almost completely blocked. If you're simply listening to a sound through free space, distance will cause both to attenuate - but your inability to hear low frequencies well will make everything turn 'tinny'. In terms of your apartment, the walls likely block the sound from your birds entirely while the pounding bass of your subwoofer makes their furniture shake."
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7cdfd7 | Why does ASMR sooth people? | Biology | explainlikeimfive | {
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"This question is impossible to answer and anyone who says otherwise is guessing at best. ASMR is not yet studied well enough because there aren't ways to reliably measure it."
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7cdm0p | what 'single-tier', 'two-tier', and 'multi-tier' healthcare systems mean | Economics | explainlikeimfive | {
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"The tier system refers to the available levels of healthcare. Single-Tier refers to only one health insurer available, which is nationally funded healthcare for all citizens. Basically, your tax dollars pay for the healthcare of everyone, across the board. Two-Tier refers to healthcare that is covered nationally like single tier, but private insurers still exist parallel to the system, for example the National Health Service in the United Kingdom, which has private insurers available parallel to it, or the United States, which has a public option, Medicare, that is limited to certain citizens, and private options above that. After looking around more, I couldn't find an explanation for what multi-tier healthcare is, as it continues to refer me back to Two-Tier, so Two-Tier and Multi-Tier are likely interchangeable."
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7cdw4j | What is RAM and how much should I be using on a phone? | Technology | explainlikeimfive | {
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"**R**andom **A**ccess **M**emory. It's where you phone puts all the data it's currently working on. All the code to run the apps that are open is also in RAM. If you're watching a video, or listening to music, it's in RAM. As long as you aren't using more than 90% of your RAM, you should be fine.",
"RAM is Random Access Memory. It's faster than storage/hard drive space, but it's slower than the CPU cache. If you have 4GB or 8GB of RAM, you're probably more than fine. Think of your CPU as a car mechanic. He has a tool in his hand that can be used immediately. In a CPU we call it a *register*. The mechanic also has a few more tools in his pockets or on his belt. These are still pretty handy, but not as handy as the stuff literally in his hands. The toolbelt is the *cache*. The mechanic also has big toolboxes in the shop. That's like the *RAM*. It's still very accessible, and you'll go there all the time, but it's a lot slower than the toolbelt. Having a lot of RAM doesn't make the mechanic work faster. It just lets him have the space for all the tools he wants. Going to the *hard drive* for something is like ordering a part online. Compared to the tool on your toolbelt, the hard drive might as well be an hour's drive away."
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7cdz0b | how do tv ads know you called "within the next 20 minutes!" | Other | explainlikeimfive | {
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"They don't. It's a marketing ~~lie~~ gimmick. I used to work for a company that did a similar thing by mail. New customers were supposed to sign up by a certain time for special rates but as a specific matter of policy we'd give those rates to *anyone* who mailed back the special offer.",
"It’s basically a scam to get you into a false sense of urgency because limited time offers make people act now and those tv infomercials are all binge purchases. The sellers could care less when you call."
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7ce4cb | When launching a rocket, does a nation have to notify other nations so as to not be regarded as a missile launch? | Other | explainlikeimfive | {
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"Each airforce has an airspace they own. What they do within their own airspace is their own business. Do not need to tell anyone But there is an upper limit. Past that limit, no one owns that space. So if you fire a rocket through your own airspace, past the upper limit and into space, then it doesn't matter But if you go into another airforces airspace unannounced, that's breaking an international law and could be received as a threat. You'd be shot out of the sky and killed. Well probably not, but they have the right to shoot you if you don't communicate with the owner of the airspace your intentions. I had a mate that flew planes and went across an airspace boarder for a few seconds and they banned him from flying for a few months and he had to go through all the mental health checks and all that initiation stuff all again, just for a few seconds across the boarder. In a glider. A plane that doesn't have an engine or any sort of weapondry, just a 1 man glider that uses the air flow to stay up in the air. It's kinda a big thing breaking an international law.",
"Explaining like I'm 3 because I'm no expert. But from my understanding each nation has a specific distance upward that remains it's own airspace, and it can do whatever it pleases there. Once the missile crosses the national border or launches to a height above its soveirgn airspace, it can become an international issue if forewarning is not given."
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7ce93w | How does sequence and separation of files in the deletion process of the computer work? | The other day I deleted a folder on my computer by accident. After a short dumbfounded three seconds the deletion process was interrupted by pressing cancel. But the process had already deleted one file of the folder. So two things I wonder about: How does the computer decide what to delete first? what gives the computer the ability to delete one file but not touch everything else? | Technology | explainlikeimfive | {
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"> How does the computer decide what to delete first? Typically the delete command will assume that the sequence does not matter, so it just uses the most easily or quickly available one. Most likely, it will just call a routine to list the contents and delete them in that order, and that routine by default lists them simply in the order the filesystem returns them. Probably in the order in which they were added to the directory, but it really depends on the implementation details of the filesystem. > what gives the computer the ability to delete one file but not touch everything else? That's not an ability but a side-effect of the fact that it has to do something for each file, and can only do one (or a few) things at a time."
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7cevi8 | How does birth control pills work and how can they prevent pregnancy? | I've always wondered how these pills work, and how can they possibly prevent a pregnancy? EDIT: Thank you to everyone for taking time out to answer! I am still a noob at Reddit so I didn't get (or notice) all the notifications. But at least I understand how the science behind birth control pills work now :D | Biology | explainlikeimfive | {
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"Birth control pills are doses of hormones, specifically estrogen and progesterone. The relatively large dose of estrogen prevents the pituitary gland from noticing the \"natural\" spike of estrogen that signals the pituitary to secrete the hormones that cause an egg to be released from the ovaries. It's like turning up your music really loud so you don't notice your phone ringing. The progesterone also affects the hormone signals for egg release (albeit through a different mechanism) as well as makes the uterus inhospitable for both egg implantation (in case one is released and fertilized) and sperm motility (by thickening the mucus in the cervix to make it harder to swim through).",
"The hormones in the pill stop ovulation. No ovulation means there’s no egg hanging around for sperm to fertilize, so pregnancy can’t happen. The pill’s hormones also thicken the mucus on the cervix. Thicker cervical mucus makes it hard for the sperm to swim to an egg — kind of like a sticky security guard. Source: URL_0",
"Typically, there are two ways the pill can work: based on estrogens, or based on progesterone-like substances. In general, both those strategies work by sending false signals to the reproductive system, using substances it uses to know when it should stop trying to reproduce. Let's start with estrogen-based therapies. For that, we first need to understand how ovulation works. During ovulation, different eggs all over the ovaries start a \"race\", like an election race, in which they rally other non-egg ovary cells around them. Those cells secrete estrogens to the outside, which are a signal to other eggs to stop trying to mature. Eventually, one egg has so many cells around it, that the amount of estrogen they are secreting is so large that prevents any other egg from trying to mature. That egg has won ovulation that month. \"The pill\" is just a large dose of estrogens, which send the signal to eggs that there is already a winner, so they don't try to mature and be secreted into the uterus where it could be reached by sperm. Then, there are progesterone-based therapies. Progesterone is secreted in large quantities when a fertilized egg is implanted in the uterus to grow into a baby. In a very simplified way, progesterone-based therapies, are just telling the ovaries and uterus that there is already a baby in the making, so we don't need another one. Most contraceptive pills use a combination of both strategies.",
"Also interesting/important to remember that women on birth control don't actually get periods. They bleed once a month because the pills contain a pack of super pills with no hormones, and the sudden change from loads of hormones to none. causes the uterus to bleed. But it's not a real period, where the uterine lining has been preparing for a fertilised egg and then shedding.",
"How does the copper IUD work? It's non-hormonal.",
"In the simplest terms, some pills are hormone doses that emulate levels of a pregnant woman. This essentially tricks the body into thinking it is pregnant and it will therefore not release an egg to the possibility of fertilization (in a pseudo pregnant state the body would have no reason to release an egg because it thinks it is already pregnant) Consequently this is also why some girls experience symptoms on the pill that are the same as that of a pregnant person. Things like clear skin, tenderness of certain regions, weight fluctuation etc"
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7cevtw | Why does ad blocker still work? If a website can detect that ad blocker is active, why can't the site also just bypass the ad blocker and display ads? | Technology | explainlikeimfive | {
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"Because they use a separate company to provide ads, which come from different web servers. Imagine they're people. Dave works for the pizza company, he delivers your pizza. Sarah works for marketing company, she delivers the ads. Now, you could put a camera on your porch. Then you only open the door for Dave, but don't let Sarah in. Dave can see that you've got a camera, so knows that you're not letting Sarah in. But he doesn't have any ads to deliver along with the pizza. Sarah has the ads, Dave only has pizza. The best he can do is say \"Hey, you're not letting Sarah in so basically you're stealing this pizza. I'm only going to give you one slice at a time to make you think about this.\"",
"Many sites just show the ad without doing much else. Adblockers, however start once the page has finished loading, and does not request more information. Sure, the page could check if the ads were hidden/removed and place them again, but this would slow the page down, decreasing potential users, and adblockers would just repeat their thing. It could basically become an infinite loop",
"Adblocker runs in the user’s browser and the website does not have any control over it. Also, the ad exchanges have a standard code that allows to work in all websites while following a certain set of rules which is recognized by adblockers. It would be quite chaotic to have specific codes for specific sites and with time they would end up being blocked."
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7cf2ay | Why is the UK is slowly stopping using £1 notes | Economics | explainlikeimfive | {
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"Pound notes were withdrawn in 1988 in the UK URL_0 Pretty sure they would not be legal tender anymore",
"Most of the UK hasn't used £1 notes for a long time. I assume you're talking about Scotland?",
"The Bank of England stopped issuing £1 notes in 1984. RBS still issue £1 notes but none of the other 6 banks with the right to print notes ever have. £1 notes are unpopular with consumers due to paper bloat and need replacing too quickly to be useful given falling purchasing power. Notes are only really superior to coins in that they are harder to forge, and forging £1 isn't really worth it any more.",
"First of all, coins are generally cheaper because they are much more durable than banknotes are. Secondly, £1 just isn't what it used to be. As the utility and buying power of a £1 note decreases (i.e. things cost more and people are moving to debit/credit cards and not using cash), it makes less and less sense to keep spending money to make them. Even in the US, using cash overall is rapidly declining. Pretty much everywhere takes debit/credit/virtual? (whatever you call using your phone linked to an online account). It just doesn't make sense to keep wasting money making cash."
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7cf8g2 | When you cry why is it your nose becomes either incredibly runny or stuffy? | Biology | explainlikeimfive | {
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"It's because your eyes and nose are connected by a small tube called the naso-lacrymal duct. It allows tears to pass from the centre of the eyes into the nose. The extra fluid in the nose then combines with the mucus making your nose run, or at the very least a bit stuffy. To expand a little: there is a similar tube, called the Eustacean tube that connects the middle ear to the nose allowing for you to equalise pressure on with side of your eardrum. When your nose is blocked this can also become occluded leading to an uncomfortable popping feeling in your ears. This is usually not an issue in adults but can lead to a rupture of the eardrum in children."
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7cfa0q | Why do images burn in to tv screens when you leave them there for too long? | Technology | explainlikeimfive | {
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"That used to be the case with CRT (cathod ray tube) displays on older TVs. Here each pixel was generated by beaming it onto the screen, and leaving the same image for too long would literally burn the screen. Nowadays with LED technologies this is no longer a problem."
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7cfbef | When cell phones first came out how did cell phone companies put up cell towers? | Technology | explainlikeimfive | {
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"You have to keep in mind that when cell phones were introduced, we already had very widespread networks (in the West) of broadcasting towers for radio and television. Wireless communication was not a new idea. Cellular service providers placed antennas on existing towers, leased land for new ones where necessary, and gradually increased coverage where it was most profitable. You need a license from the government for a broadcasting installation like that, as well as permission from local government. From an early stage, people came up with the idea of providing service via satellite, without having to build all those towers--but the ambitious schemes for global coverage never really materialized. There are a few satellite constellations now which provide pricey service that's not high quality, but it's very helpful in areas with no towers at all."
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7cfdoc | If you drink a lot of coffee or tea does that count as drinking a lot of water? | Biology | explainlikeimfive | {
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"Yes. In fact, my doctor recommended that I add coffee to my water to give it a bit of flavor. So, I started brewing a pot of coffee and diluting it 1:1 with ice water. Throughout the day I drink 3/4 of a gallon of this mix. It's just black coffee and water: no sugar/ cream. It does keep me hydrated and no- the caffeine does not dry me out. I",
"Contrary to popular belief; drinking any of the various liquids fit for consumption throughout our day is better than drinking no fluids at all. Coffee, liquor, tea, whatever you will; they will all hydrate you, just less so than water."
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7cfs9k | What’s the differences between involuntary manslaughter, voluntary manslaughter, and murder? | Other | explainlikeimfive | {
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"Involuntary manslaughter means that you killed someone on accident, but you were doing something that you should have known was dangerous and that you shouldn't have been doing. For instance, running a red light in your car and crashing into another vehicle, killing the driver. Voluntary manslaughter means means that you either meant to harm someone but not kill them, but they get accidentally killed in the process (for instance, you get into a fight and want to seriously hurt your opponent, but accidentally kill them instead) or you meant to kill someone, but you didn't plan it, and it was \"in the heat of the moment\" (for instance, if you come home to find your neighbor raping your child, and you beat them to death). Murder means that you meant to kill someone, and you planned it ahead of time. For example, you knew that you neighbor had been molesting your child, so you invite them to go hunting with you so you can shoot them while you're out in the woods and bury the body.",
"While most of the answers are more-or-less correct, it's important to note that these are all legal terms that may (and often do) have different meanings depending on the jurisdiction.",
"Involuntary manslaughter : you killed someone without meaning to. I.e. drunk driving and hitting someone Voluntary manslaughter: you killed someone in the heat of passion i.e. you found a man in bed with your wife andbkilled him. murder: you killed someone after thinking about it. i.e. you killed the guy you found in bed with your wife after a few days",
"Example: A man (Adam) is sitting in his garage working with a bench grinder. His neighbor (Bob) comes over from across the street to complain about the noise. There are no restrictions on Bob's movement; there is no fence, no \"no trespassing\" signs, no verbal/written warnings to stay off the property, etc. * Scenario One: Hoping to discuss the matter with Bob, Adam sets his work piece on top of the still running bench grinder and goes to talk it out. Partway through the discussion the work piece falls onto the spinning wheel, and is flung into Bob's throat at a high rate of speed, severing a major artery and compromising the spinal column. The trauma is fatal. Adam has committed Criminally Negligent Manslaughter, a form of Involuntary Manslaughter; he did not willfully set out to harm Bob, but as a direct result of his incompetence (the fatal wound could have been prevented with a flip of a single switch, or just setting the work piece down on a different bench) Bob is dead. * Scenario Two: \"How about you mind your own f__king business, Bob?\", says Adam, before throwing a nearby wrench at his neighbor. The wrench catches Bob right between the eyes, stunning him and making him fall roughly on the driveway, smacking the back of his head against the cement. The trauma is fatal. Adam has committed Constructive Manslaughter, a form of Involuntary Manslaughter; he did not intend to kill Bob, but caused his death while engaged in an illegal and unprovoked attack on his neighbor. * Scenario Three: Bob doesn't stop at complaining about the noise; it turns out the grinder noise was just the last straw, and it becomes and argument. Complaints become yells, yells become screams, screams become shoves, and then Adam strikes Bob in the head with his work piece. The trauma is fatal. On review of the exact circumstances leading up to the blow, the prosecutors bring Adam up on charges of Voluntary Manslaughter (also known as Third Degree Murder in the United States); he entered the scenario with no explicit intention to kill Bob, and did so during the heat of the moment, but still made a willful decision to fatally attack his neighbor. * Scenario Four: Like in scenario three, Bob brings the anger, only this time Adam turns off his grinder and walks back into the house... only to come out with a shotgun, and delivers a 12 gauge deer slug to Bob's torso, compromising his intestines and right kidney. The trauma, after multiple hours of horrendous pain, is fatal. In the following interview, Adam says in no uncertain terms to the officers that he considered calling the cops after retreating to the house, but instead chose to grab the gun and deal with it himself. He did not fuss with ammo selection (deer slugs were what was already in his shotgun), nor had he contemplated killing Bob at a prior date. Adam has committed Second Degree Murder; he fully set out to kill someone, knowingly and willingly (also known as malice aforethough), but did not sit around plotting the crime; he did not sit around and plan a murder, he simply grabbed an available weapon and killed someone. * Scenario Five: Like scenario four, Adam comes out with the shotgun... only he misses, puts the slug through Bob's kitchen window and catches Bob's wife (Carol) in the back of the head, thoroughly rupturing her skull and splattering blood and brain all over the pie she was making. The trauma is fatal. Adam swears on everything holy that he was trying to hit Bob, he had no ill will towards Carol, and this whole thing is a horrible mistake. He still committed Second Degree Murder. He set out to kill someone with malice aforethought but without premeditation, and the fact that he cocked up and killed the wrong person doesn't help him any; the law doesn't really give a crap that he hit the wrong person, only that he set out with murder on his mind and killed someone. * Secnario Six: Adam and Bob share some words, things get a bit heated, but Adam turns off the grinder and Bob goes back home. Two weeks later, Bob's grown-up kid who lives out of town asks the police to do a wellness check on Bob and Carol because they haven't been picking up their phone. The police find that the back door has been forced open, Bob's car is gone, and a significant volume of blood is on the floor of the bedroom. After a search, the car is found in a scrapyard two counties over, with Bob and Carol's bodies in the trunk, and a chunk of steel lodged in Bob's throat. Forensic examination finds a partial fingerprint on the steel piece, and approximates a time of death. On a routine interview, a detective notes that Adam has metalworking gear in his garage, and inquires about Adams whereabouts on the evening in question; his claim that he was out at the local sports bar at the time is not corroborated by the staff or security cameras. Digging deeper, the police find evidence of Adam having bought a one-way bus ticket from the county where Bob's car was dumped. Adam is detained as a suspect, and following an interview is arrested. His fingerprint is found to match the partial on the murder weapon. At this point (against the advice of his lawyer) Adam tells all, admitting that the murder weapon is the workpiece from the day of the confrontation, and that the owner of the scrapyard was an old friend who would crush the car without asking a bunch of questions. Adam has committed two counts of First Degree Murder; not only did he explicitly set out to kill people, but he also sat down and plotted, making it a \"cold blooded\" or \"premeditated\" murder."
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7cfsyr | how can Jupiter and Venus pass in the sky when one is closer to the sun and one is further from the sun than us? | Physics | explainlikeimfive | {
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"It has to do with relative position in the three orbits. Have a look at [this diagram]( URL_0 ). Earth is in blue, Venus in green, and Jupiter in orange. Venus appears to pass in front of Jupiter, despite being closer to the sun than we are.",
"It seems confusing because it's easy to think of one as *behind* you and one as *in front* of you. Instead, imagine you're running a race around a track. You're in lane three, Venus is in lane two--closer to the center, and Jupiter is in lane five--farther from the center. At some point in the race, you might look across the track and see Venus and Jupiter running \"side-by-side\" even though they are actually separated by quite a distance.",
"Perspective. They aren't passing so they can high-five each other, it just appears so despite great distances between them."
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7cfu9o | what is the difference between Dow and Nasdaq? | Economics | explainlikeimfive | {
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"There are a variety of stock exchanges across the world. In the US, the biggest are the NYSE, AmEx, and NASDAQ. Each exchange has rules for companies that want to list their stock in their exchange, but, assuming the rules have been met, a company can choose whatever exchange they want. (There are some companies whose stocks are listed in multiple exchanges at the same time, but they're uncommon.) The Dow, more formally the Dow Jones Industrial Average, is a collection of 30 stocks from across multiple exchanges intended to show how the stock-based economy is doing in general. The stocks are chosen by the people who run the DJIA and are intended to be market leaders in a variety of different industries. NASDAQ also runs a similar index called the NASDAQ Composite that is comprised of basically every stock listed on that exchange. The NASDAQ exchange is significantly populated by modern technology companies like Apple and Google, so the index is generally noted as how well the computer and related technology industries are doing.",
"The Dow is an index of 30 stocks. It used to be just NY Stock Exchange listed stocks, but they began including NASDAQ stocks, too, 10 or 15 years ago due to rising importance of tech companies. The NASDAQ is an index of companies listed on the NASDAQ exchange. Companies going public have the choice of which exchange they want to list on."
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7cg4h0 | Why does FM stations starts at 86 to 110 rather than other numbers? (Atleast where im from, SEA) | Other | explainlikeimfive | {
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"The numbers represent the frequency, in megahertz (MHz) at which the radio station transmits. The reason that they're always odd (88.9, 89.1, 89.3, etc.) is because each station is allocated a 200 kilohertz (KHz) bandwidth. So those stations actually have a range of 88.8-89.0, 89.0-89.2 and so on. You're tuning the radio the center frequency. These frequencies are the result of science and regulations. Those frequencies allow the signal to travel far enough to be useful but not so far as to interfere with neighboring cities' stations on the same frequency. FM radio goes about 50-ish miles (AM goes much further in the right atmospheric conditions. At the same time, the FCC in the United States controls the radio frequency spectrum to prevent interference. TV, satellite, cell phones, air traffic control, CB, Wi-Fi, anything that transmits wirelessly takes up a spot on the spectrum and shit goes wrong when those interfere.",
"In the early days of radio, it was the wild west, anyone could broadcast anything on any frequency. This was a real problem, especially when it came to government communication, like keeping touch with ships at sea. By 1930, most developed countries decided the government \"owed\" the broadcast spectrum, and started to regulate it. In the US the FM band originally was 42 MHz to 50 Mhz These stations were affected by tropospheric skip that allowed the signal to bounce off the atmosphere and allegedly interfere with other distant stations. RCA, heavily invested in AM, championed the move to disrupt the rival FM band, so it is unclear to what extent this was a problem. In the late 1940s, the band was moved to 88 MHz through 108 MHz, a range less prone to skipping, where it remains today. [Here]( URL_0 ) is the current allocation spectrum the US uses.",
"Fun fact: if the stations call letters start with a W then the station is east of the Mississippi River. If it starts with a K it’s west of the Mississippi. Edit: ok is a fun almost fact.",
"Eli5, why do most US radio markets have similar programming in various frequency ranges? Ie, 86-90 religious, 90-29 NPR, etc? Are lower frequency stations cheaper to operate?",
"The low end of the FM spectrum butts up against the old analog VHF spectrum for TV. All the major stations have gone digital but low power stations were granted an exemption for analog. What does this mean? In some places you used to be able to pick up TV audio on the lowest couple frequencies of the FM band. To this day, there's a low power station in Chicago, WRME that is legally a low power analog TV station but they market themselves as a radio station.",
"Because those are the frequencies the local government(s) have assigned for commercial radio stations. Other frequencies are used for other things, and in other parts of the world commercial radio uses different ranges, too.",
"A neat infographic showing the allocation of radio frequencies URL_0 Relevant",
"The main thing here guys is that yes you can listen in and just listen to both the airplanes and tower but for the love of god don't try to talk to them. As an air traffic controller its just makes our day harder. Plus, not really sure about it but it may also be illegal.",
"Here is a cool map showing the uses of the frequencies and by whom URL_0",
"This is the actual frequency of the signal. By comparison, things with numbered channels, like TV or Wi-Fi or CB have a table somewhere matching the channel number to the frequency. As a side note, in the US, the channels for FM radio do have numbers but only the regulators use them. The lowest is channel 200 (87.9) and they go to 300 (107.9). The space immediately below 88 is used for TV and the space immediately above is for aircraft use. 87.9 actually overlaps a TV channel and can't be used except where the TV channel is not.",
"Because other frequencies are used for other things by law. I learned this when I was in the army and we used our military radio to listen to a rock station. Had we talked on that frequency people in their cars nearby would have heard us. (Training so no crypto loaded)"
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7cgag5 | I find myself getting Electrical / Static shocks a lot more than family, friends or colleagues. Is there a reason why a person might be prone to shocks? | Biology | explainlikeimfive | {
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"The most likely explanation that comes to mind is your clothing. You can generate static electricity via the [triboelectric effect]( URL_0 ). When dissimilar materials rub or separate it can cause a static charge to build up. The amount of charge depends a lot on the particular materials. One of the materials that is renowned for this is polyester. If you have polyester in your socks, or in your carpeting or rugs, it can be easy to build up a big charge. But polyester isn't the only material prone to this. A classic experiment is to rub a cat with a wool cloth, for example. I used to have a car that caused me to generate a lot of charge when I slid off the seat. I learned to first touch the outside door handle with the palm of my hand instead of my fingertips so that the shock wouldn't feel so intense."
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7cgcan | Why can you get shots to cure outdoor allergies (e.g. grass, pollen, mold, etc), but not for food allergies? | As I kid I went to the doctor once every two weeks for my outdoor allergy shots, and they worked wonders—got rid of my constant migraines and allowed me to go outside without having a hellish time. So why can’t I receive a shot that slowly introduces the protein involved with the problem food into my bloodstream, like outdoor allergy shots do? | Biology | explainlikeimfive | {
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"Remember, medicine proceeds only as fast as is driven by evidence. Something can look like logical science but when one tests it, it doesn't work. The fact is that there are lots of different types of allergies, driven by different facets of the immune system: some respond to desensitisation therapy (which is what you're asking about) and some don't. I've been in medicine for years and it has been frustratingly slow progress. Parenteral (injection) desensitisation therapy works really well for wasp and bee venom. It works well, but not as dramatically, for respiratory pollen allergy (usually upper airway more than lung). But the results for other areas have been disappointing. That's why it's not used... Oral desensitisation therapy, which is potentially a lot safer, has had mixed results - there has been research in this area for 20 years. As I said, very slow. Watch out for specialists who promise great results without questioning the evidence. It varies and it's worth doing some homework.",
"You absolutely *can* get food allergy treatment like this. For convenience, often it's done orally -- after all it is a food."
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7cgefm | Why do we scream when scared? | Biology | explainlikeimfive | {
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"To warn fellow members of our species so they can survive and carry on our species in our place.",
"Two reasons that spring to mind from animals: * Attract attention of others. * Attempt to scare off a predator by loud noises and exposure of teeth. Like dogs barking, cats screeching etc."
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7cggh8 | What happens in your body when you consume alcohol or do sports while taking antibiotics? | Biology | explainlikeimfive | {
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"Alcohol very-very sugary (has abnormally high amount of calories). Goes in your body. Body wants to add water to make alcohol less sugary (body needs water to make the high calory, sugar saturated alcohol dilute to digest it). You drunk, no water nearby. Brain 80% water. Body takes water from brain (not exactly brain, but the protective balloon like structure protecting it). Brain thirsty. Starts running merry-go-round (hangover). You become unconscious. This is the best way I can explain to a 5yo. You can ask me to explain it in a more elaborate manner when you grow up.",
"Someone with more time is probably typing a whole article for u so imma just simplify the answer till he posts. Bacteria can make you sick so your immune system fights them. Antibiotics assist ur immune system in killing bacteria cells that are sensitive to it. Alcohol and sports take some of ur body's focus off fighting the bacteria to heal muscles when u exercise. Well alcohol doesn't help ur body much either at this state. Both may not directly influence the drug mechanism but more ur body's healing process"
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7cgk50 | why is it sometimes we can't say a word or name even though we know it? When it's 'on the end of our tongue' but we literally just can't say it | Biology | explainlikeimfive | {
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"Error: Segmentation Fault Seriously though, I think that this is really what's going on. Our brains are constantly overwriting old information with new information. When it does so, there are some lingering neural pathways to concepts that were recently overwritten, akin to a dangling pointer in programming. The difference is that since our brains are massively adaptive, we can essentially extrapolate the missing information given enough time. Not a neuroscientist, but I think this is a plausible explanation. Maybe someone with more research experience in the area can comment on this further.",
"Great description! It’s actually called the Tip of the Tongue phenomenon (TOT) and it’s exact origin is up for debate. The most commonly accepted reason is it is a partial recall where one cannot recall exactly the word, but maybe a first letter, the circumstances where the word applies, or it’s syllabic stresses. It’s an issue of memory retrieval so it’s in there somewhere, it’s just a matter of retrieving it successfully!"
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7cgkar | If a Hermaphrodite had full working sexual systems from both sides, would they be able to get themselfs pregnant? If so would it be classed as Cloning? If not. Why? | Biology | explainlikeimfive | {
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"OOH okay as a hermaphrodite I feel this is my time to shine!! It really isn’t the most documented condition in the world so it’s hard to say, I’ll be the first to admit I haven’t had a specialist examine me, just a dozen or so very helpful nurses and doctors from sexual health clinics and the like. A bit of science I don’t understand from several blood tests and tissue samples and it was discovered I have a 3rd sex chromosome, Likely a XXY so I have the double X to make all the girly bits and a Y for all the rest. The only problem is eggs and sperm take half of your dna randomly and they can’t have a half chromosome so you get some with single sex hormones, some with double, it’s a real clusterfluff. This means there’s a large number of possibilities on the sperm/ egg combos you can make from my dna just in terms of Xs and Ys and of course many of them will not produce a sustainable embryo. So to answer your question it’s a game of chance, you could theoretically have a child with the same DNA, it’s hard to say if it’s a clone as it blurs the line between sexual and asexual, and sadly there’s a large proportion of possibilities that will never survive. All the other not identical but survivable combinations would produce a child that has similar deformities to a child conceived by two siblings. Little end note for you I am pretty dyslexic so if that is worded terribly do ask what I mean and I can try break it down more:) This is just added in an edit, I should probably say that it’s not exactly a perfect set off both down there, I’m talking very theoretical here, if you could easily extract an egg and a sperm and neither have any super genome fucked side effects, that’d be the case, I don’t actually know if I am fertile in either sexes case. The practicality of this is sorta nil 😕",
"Generally a hermaphrodite doesn't have any fertile genitalia. Rarely they will have one set that is fertile, but the other set is not. I have never heard of a case where both sets are fertile, so I'm not sure if it's possible. If it theoretically did happen, then no it would not be cloning. You see cloning is when you copy both sets of something's dna. In this example you would have two different gametes that are each randomly mixing and matching genes from both sets, plus adding in random mutations. The result is more like super inbreeding.",
"Although the phenotype is fixed at conception, we start out as sexless embryos whose structures later differentiate. That is, the same gonadal structure differentiates into an ovaries or testicles. A penis and clitoris come from the same structure. The structure which becomes the uterus in a female becomes the vestigial [prostatic uricle]( URL_0 ) in the male. So that's why you can't have both, the structure can go one way or another or, in rare cases, stay intersexed, but you don't get a second set of gonads. In rare cases you could have mutiplied organs, like having a third arm. The interpretation of this is is that it's from an undeveloped twin, which may be a division into an identical twin that didn't finish, or a fraternal twin- which makes you a *chimera* (two organisms fused together). A person could be a chimera with a different-sexed twin and have a second set of gonads. However, it's not possible to develop as two genders with the same blood supply. The hormones that guide development are shared, and incompatible. One or both sets would be undeveloped and dysfunctional. IF, somehow, both sets DID develop and become functional, they would be gonads from fraternal twins, which is siblings. If they got themselves pregnant, somehow, the offspring would be the same as sibling incest, which comes with huge risk of birth defects. This has never happened with humans, or AFAIK any mammal in the lab. IF you had an identical-twin set of duplicate gonads, they would develop as the same gender (four testicles, lucky you! I guess...) IF you were literally a mad scientist and used two of them from the male embryo to replace another female embryo's ovaries with them via transplant, they retain the male phenotype and probably could not develop into ovaries. They would make testosterone and virilize the embryo into an intersexed individual incapable of reproduction. Also, you've committed a gross crime against humanity, but this is about the science.",
"URL_0 In theory, yes. In practice there have been no documented cases of a hermaphrodite with both reproductive systems working.",
"First off: hermaphroditism (having both functional male and female reproductive systems, either simultaneously or at different points in one’s life) does not exist in humans. Everyone in this thread seems to have confused it with intersex conditions, in which the reproductive system forms in a way that is not clearly male nor female. Intersex people have often been called hermaphrodites, but this is misleading and scientifically inaccurate. They do not have two separate reproductive systems; they have one which is neither male nor female and they are typically infertile. As for actual hermaphroditic organisms, self-fertilization is pretty common, especially in plants. It does not result in clones, because genes recombine during fertilization. Imagine shuffling a deck of cards; you’ll wind up with all the same cards, but getting them in exactly the same configuration again after shuffling would be astronomically unlikely. The child would be extremely genetically similar to their parent, but would not be a clone.",
"No the child would not be a clone. Genetically it would be the same as if two siblings mated. As far as I understand it, you can't create a clone through the germ DNA (sperm or egg) because that's always recombinant. Meiosis scrambles the genes during meiosis 1 so the combination of alleles is always different",
"I want the OP to go back and think about the question. Then take a look at brothers and sisters and ask why they don't look the same. That should be your question.",
"Meiosis, the generation of haploid gametes (eggs and sperm), guarantees some amount of genetic variation through genetic recombination for every single egg and sperm produced. You could have an offspring that might look and behave nearly identical to its parent, but to qualify as a clone, which means genetically identical, is next to impossible through self-fertilization."
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7cgn2s | What holds fingernails in place? How far under the skin do they go? | Biology | explainlikeimfive | {
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"Your fingernails and toenails are made up of cells that form into a hard surface called keratin. Keratin is also what makes up your hair and other parts of animals, like horse hooves and rhino horns. Underneath your fingernail is a soft surface called the nail bed. This is what produces the cells that harden and turn into keratin. The nail grows because it works kind of like the plates that make up the Earth’s crust: The nail bed forms new cells, which push on the older ones and make them grow outward. The whole structure inside your finger doesn’t extend much past the bottom of your visible fingernail.",
"The nail is generated (grows from) the germinal matrix and grows over the sterile matrix (nail bed). If the nail is crushed, injured, or removed, the germinal matrix and nail bed need to be protected . A defect to those structures can cause permanent nail deformities. So after a crush injury, it's standard practice to remove the nail and inspect those structures. We use a freer elevator to gently lift it off. Once any repairs are made, the nail is slid back into place and sutured back to hold it as a splint. The nail regrows and pushes the old nail off. If there is a nail deformity, we can either remove the nail and attempt to address the deformity, or remove the nail bed and matrix to eliminate the nail regrowth entirely.",
"To add to this why don't fingernails hurt when they grow? Shouldn't they tug on the skin underneath?"
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7ch067 | how does the body correctly sort food and fluid (especially when you eat and drink together)? | For example I have seen some eating contests where the participants eat huge quantities of food and drink water to held them “down” it quickly. When it gets down your food pipes* how does the stomach and bladder get their individual shares of what’s been consumed?? *forgot the sciency name. | Biology | explainlikeimfive | {
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"> When it gets down your food pipes* how does the stomach and bladder get their individual shares of what’s been consumed?? The sorting happens in the intestines. It makes intuitive sense that the solids you eat become poop and the liquids you drink become pee, but that isn't actually true! Everything you swallow goes to your stomach, where it all gets mixed and broken down into a soup-like consistency. Then it goes to the intestines. Your intestines absorb the water out of it (including water that used to be in solid food), and absorb the nutrients. What's left over at the end of all this absorbing is poop. Poop also contains a lot of old, dead cells from the intestinal walls, and bacteria. All the water and nutrients that got absorbed will flow around in your bloodstream, going where they need to go. Once this is done, the extra water is filtered out by the kidneys, because a lot of the waste products we need to pee out (like urea) have to be dissolved in water.",
"The bladder is not directly connected to the digestive system, so there's no \"sorting\" involved. The small intestine extracts water and nutrients from the food in to the blood, with the help of friendly bacteria, and you poop out what's not used with a lot of dead bacteria. The kidneys, on the other hand, filter impurities and waste products out of the blood, with some water, and sends them to your bladder."
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7ch0p9 | Why do smartphones need sometime hours to fully charge. Electricity and electrons are so fast... | they should be able to charge it in a second. Whatever the capacity of the battery shouldn't it instant charge with all that powers from the socket? | Technology | explainlikeimfive | {
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"Electrons do not move at the speed of light, they are pretty slow actually. What propagates at the speed of light is the electric field that makes the electrons move. Every conductive material is pretty much filled with movable electrons, like a garden hose that’s already full of water. As soon as you turn on the water, it comes out the other end because there’s already water there that is pushed out and it doesn’t need to fill the hose first. gravity is similar: a gravitational field propagates at light speed but the mass it affects doesn’t. That’s why meteors don’t fall to earth at the speed of light, which would be disastrous. In rechargeable batteries, there’s also the charging itself which is a chemical reaction that takes some time as well.",
"* Batteries are charged through a chemical reaction. Those don't happen instantly, especially in the case of batteries. * The faster a battery is charged the more current it draws (electrons smashing into things inside the wires) and the more heat it creates. * Heat is bad for batteries and can cause cell phone batteries to catch fire or explode. So the charge rate is limited to what is safe for the battery.",
"You can't charge in a second for a few reasons. Ignoring efficiency losses, a typical 10 w-hr cell needs 10 watts for one hour to fully charge. A one second charge would need 36,000 watts (10x60x60) for one second. That would require a huge expensive power supply with very heavy cables and connectors. You can't force 10,000 amps through a tiny wire. The chemical reaction in the cell which is responsible for charging can't be rushed. To do so would generate too much heat. The cell would explode. The maximum allowable voltage of lithium ion cells limits the speed of charge. Li-ion chargers can charge faster at the beginning of the cycle. The speed tapers off towards the end. Some battery chemistries like lead-acid or ni-cd allow for higher voltage fast charging for the entire cycle. Edit: Lead acid and ni-cd batteries still have charge speed limits."
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7ch12t | How does a "dead spot" occur on a tennis/basketball/whatever court? | Rather confused after seeing this URL_0 It isn't clever editing, apparently this actually happens, but why though? O.o | Physics | explainlikeimfive | {
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"It indicates a defect in the pavement -- an area where the surface is covering a bubble. When the ball hits this, it simply mashes down the bubble -- which is a soft surface, not a bouncy surface."
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7ch1fs | Why is it that when a vehicle reaches a certain speed, it’s rims/hubcaps appear as though they’re rotating backwards? | Physics | explainlikeimfive | {
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"Your eye can only pick out some of what's going on. When the wheel is spinning that fast you are seeing it at one moment and then the next moment the wheel has actually rotated 'almost' a complete rotation so it appears to have rotated slightly backwards."
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7ch4lq | Why is it unsafe to thaw meat outside the fridge? Won't cooking it destroy any added bacterial load? | Biology | explainlikeimfive | {
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"Cooking it kills any bacteria, yes, but if bacteria already grew and produced toxic materials, cooking may not destroy the toxic materials.",
"You're not guaranteed to get sick, but it increases the likelihood of it. A lot of bacteria that cause food poisoning secrete stuff that is the cause of making us sick. Some of the compounds they produce are stable enough that cooking doesn't destroy them, but will destroy all the living bacteria. It's generally recommended to thaw things in the refrigerator overnight, because it's cold enough to drastically slow bacterial growth, but warm enough to thaw frozen things.",
"I've literally defrosted meat outside my fridge my entire life.... never ever had a problem never ever got sick."
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7chf5d | How is a mathematical problem/equation “unsolvable” or “unsolved”? | Mathematics | explainlikeimfive | {
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"Mathematical problems are not arithmetic or algebra problems like you might see in school. While those skills are often necessary for mathematics, they are not a good representation of the actual questions considered by mathematicians. Research problems in mathematics are conjectures about some abstract structure, usually but not always infinite in size, and to \"solve\" the problem is to logically prove whether the conjecture holds. For example, one classic result is [the proof that there exist infinitely many prime numbers]( URL_0 ). This is not something you can check by testing all the cases (there are infinitely many numbers to check), or by manipulating an algebraic equation (what equation would you even use?) - you need to reason logically about what it means for numbers to be prime. This proof has been known for a long time, but there is a related conjecture that is still unsolved: whether there are infinitely many *pairs* of prime numbers that are 2 apart from each other (ex. 3 and 5, 11 and 13, 17 and 19). There are many such pairs known, but proving that there must be infinitely many has turned out to be very difficult.",
"This can be pretty neatly be answered by an example. So called Collatz conjecture is unsolved problem in mathematics, and it is easy to explain in just a few words and elementary school arithmetic. Take following rules: 1. Pick a positive integer N 2. If N is divisible by 2, divide it by 2. Otherwise, multiply it by 3 and add 1. 3. Repeat step 2. So if I pick 3 as my number, it's odd so I multiply by 3 and add 1 to get 10. That is even so I divide by 2, getting 5. That is odd, so I multiply by 3 and add 1, getting 16. Then I just keep dividing by 2 until I reach 1. That's odd, so I multiply by 3 and add 1, getting 4, then 2, then 1, then 4, then 2,.... So 4,2,1 loops endlessly. And the question is this: do all starting numbers eventually come back to that 4, 2, 1 loop? This is unsolved question. Feel free to try it out, but don't be discouraged if you don't solve it, the most brilliant mathematicians have tried to solve that one but it has remained unsolved for a long time. Problem being unsolvable means basically just that it cannot be solved, at all. If I have picked two numbers, a and b, and their sum is 5, can you tell me what a and b were? You obviously can't"
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7chi2a | Why do Home dishwashers need to take 3 hours? I know it’s for energy star requirements, but commercial machines get the job done in 90 seconds. Why the massive difference? Wouldn’t even a more powerful motor take less electricity for such a big time difference? | Technology | explainlikeimfive | {
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"The dish machines in kitchens are SUPPOSED to be sanitizers, not dish washers. The poor sucker getting paid barely enough money to survive is the dishwasher. All the machine is for is removing whatever small bits are left over after the dishwasher has already mostly cleaned them off. Long story short: If you want clean dishes quickly, you're gonna have to get your hands dirty. Source: Am Chef",
"also, it's important to note commercial restaurant washers don't have to deal with stuck-on, dried food. The plate comes back from the table, gets pre-scrapped, then rinsed with a high-pressure manual spray, with hot water. The plate is essentially clean now, save for a few random bits. Food never had a chance to dry, thus it is very easy to wash quickly. Silverware soaks in hot water up until the dishwasher has enough to do a full load, so they don't dry out either. The same plate might serve ten people in one weekend dinner service, it comes down to just how FAST plates move through a busy restaurant. Homes don't work like this. People let food dry out on the counter, or in the machine itself waiting on a full load. A longer cycle is necessary to re-hydrate the stuck-on food before it can be carried away. Take an average load of dried dishes from home, I guarantee most of them would not come out clean in a commercial dishwasher, and would require many, many cycles. The restaurant machine exists only to finish plates that are basically 99% clean already. The detergent just takes away remaining oil/butter, and the rinse cycle gets the plates to a high enough temperature to sanitize, with the help of a little bleach. Rinse aide makes them dry quickly. Within ten minutes it's heading back to a table. An average \"round trip\" is under an hour. Any plates or equipment with real stuck-on bits must be manually scrubbed. It's comparing apples to oranges.",
"Oh, finally... My time to shine! I didn't read through all the comments so others may have mentioned all of this already. I work for a major appliance manufacturer and this comes up quite often. One main reason is the fact that they are using so much less water - we're talking just a few gallons. That water is run through the wash arms at different times, so not all of the dishes are being sprayed and cleaned at once. Another reason is due to the sensors inside that tell the dishwasher how dirty the water is. So many people think they are supposed to essentially wash the dishes before putting them in the dishwasher - STOP THIS! It needs to sense the food/drink particles in order to clean properly. And as mentioned in other comments, heated dry. While it adds to the time, heated dry, along with rinse aid, is essential to getting your dishes (and the inside tub) dry. If you don't do these things and your dishes aren't dry, don't call the manufacturer. Read the manual that gives with it. Any other fancy options you may add on, say sanitize, are going to add to the time as well. Mind you all of this applies to the brands I work with, but I'm sure there is some crossover to others as well. Edit: my first ever gold! Thanks, my fellow Redditor! I'm so glad this random knowledge has finally paid off.",
"Commercial dishwashers take 45 mins to heat up when you turn them on, then keep the water hot all day, which saves a massive amount of time in the wash cycle but uses a lot of power. domestic dishwashers heat the water every time.",
"More complex chemicals, which are surprisingly expensive. Significantly higher temperatures and pressures. Higher voltage. They basically turn your dishtank into a loud sauna too, you probably wouldn't want your kitchen like that.",
"They run on very hot water, use dangerous chemicals, and are far too forceful for normal dishes. That's part of why restaurant dishes and mugs are so thick.",
"The commercial dishwasher has a tank with pre-heated water, i.e. in the very moment you close the cover, a wet hot hell with chemicals goes down on the dishes, and everything is done when your dishwasher at home is still thinking how much water to take in and heat.",
"Additional Eli5: why does my household dishwasher from '05 take 88 minutes per load and my girlfriend's 2017 washer take 180 minutes?",
"Along with everything else is dry time. Commercial dishwashers you a drying chemical and air drip dry. Your dishwasher turns into an oven and baked the moisture away. It needs to do this because your not there to open the door and create air flow as soon as it finishes. If you didn't open your dishwasher for a day or two those dishes would not be clean any more, mold would have started to form",
"You hit it on the head. Residential dishwashers are bound by EPA regulations. Lower water/electric consumption. Commercial dishwashers do not follow these. Sinners circle explains how proper balance of chemicals, mechanical power, time and temperature need to be balanced for cleaning. URL_0 If you reduce temperature/mechanical power (to save energy) you must increase time to balance sinners circle. This is where commercial dishwashers can clean in 15 minutes or less. Extremely high water temperature and pressure = low time.",
"Residential dishwashers don't need to take 3 hrs, as many have \"quick\" or 1hr cycles. But if you want to use less water(and electricity to meet Energuide or energy star guidelines) a residential dishwasher will utilize sensors to measure the turbididy of the water(which can eat up a portion of the cycle time and uses a fraction of a penny for each use and some dishwashers will reactivate the sensor portion up to 3 times per load at anywhere from 5-10 mins approx per sense). The filling process will also take time and others have pointed out that heating water through an element will also add time(if you have a 'high heat' option it will add more time as to heat the water up even further, in most cases surpassing what your hot water tank heats to). Then filtering the water. Most \"newer\" dishwashers can filter and reuse up to 75% of the water, some like KitchenAid, in some models, after filtering and reusing water only use about 2.25 gal per load(compared to the average 5-7 gal per load of most other models).The filtering process can also eat up some of the overall cycle time. Also drying. Condensation drying, which is used by most brands can take a long time. Having heated dry option uses more electricity but has a shorter run time(and \"newer\" options like adding fan assisted heated dry help reduce overall times as well). Also unlike commercial applications where you can have a person target a powerful sprayer at baked on foods, at home the machine will operate the bottom sprayer for a time then utilize the middle and top sprayer and cycle back and forth(some machines like Maytag use all the arms at once as the motors on those machines are more powerful but won't reduce cycle times by doing this) hoping to get all the food off(as some have mentioned the need to \"rehydrate\" soils to help get them off is factored in the programming/cycle choices which also plays a part in the overall timing). Source: I work for an appliance manufacturer and spend time with the engineers who build/design/program them. TL; DR: residential dishwashers don't need to take so long but to enjoy resource efficiency(and get dishes clean without you assisting them)they need to do stuff that adds more time. Edit: formatting",
"You do not have the pressure and the temperatures that a commercial system has. Those things are monsters and the water is at boiling temperature. Here is a video. URL_0",
"Temperature, chemicals and manual labor is the difference. For the commercial dishwashers: You need to scrub debris off the items you want to wash as much as you can (someone said something about sanitizing plates... this is what is happening.. just at a faster rate of speed due to the temperature and chemicals) Temperature: wash temperature is about 160F(very hot) in most commercial dishwashers. Home dishwashers could get there but only if your water heater is up to it... most water heaters at home do not have a booster heater like the commercial dishwashers (they are powerful) and they are installed in the machine IN the water tank. The rinse cycle comes right about the end of the trip and the temperature of the water gets to about 180-190F(Extremely hot1!)... the chemical evaporates over 200 degrees and it is worthless then. Most newer machines have a computer that monitors the temperature and keep it at that level. they also let you know when the chemicals are low or at zero level. Chemicals: soap is present at wash cycle. most machines have nozzles that spray the plates/hardware you are washing. All this is pressurized but it wont take all the heavy debris (hence the manual step) then the rinse chemical allows for a faster drying time. Usually all the items that go thru the cycle come out clean, sanitized and dry after the cycle(about 2 min tops). Rinse chemicals allows for a faster dry time. The home dishwasher does not have the chemicals, temperature of the commercial machine. Which translates in longer time to clean the dishes. So, the difference is the temperature and the chemicals. If restaurants do not follow these procedures or skip part of it... they will go the way of the Dodo. Washing dishes one of the most important part of the restaurant business. Source: I have been in the restaurant business for about 30 years. I started as a dishwasher. Yes, I still help wash dishes and check they are being washed properly. Clean plates saves the business. I check daily that my machine has proper temperatures, chemicals and the water gets changed at least every two hours(that also affects how clean the plates come out)",
"Since no one seems to answer the obvious answer, I'll say it. Commercial dishwasher **are not** energy efficient. You can either have quiet and energy efficient, or loud and quick. Commercial dishwashers take the latter and residential dishwashers take the former.",
"When I was younger and worked in commercial kitchens the dishwasher wasn't s washer at all. It was just a hood you pulled down that sprayed boiling hot water and rinse aid on the contents to sanitize the dishes and make them sparkle!",
"Professional dishwashers only have to remove \"fresh\" remains that are still moist and relatively easy to wash off. They use pretty aggressive detergents that should only be handled by professionals. They are great for greasy stuff but are not that great washing off starch and proteins (eggs in particular). Your dishwasher at home on the other hand may have to wash of dried stuff from two days ago and uses milder detergents that are safe for home use. Also, they have different components that are good at decomposing starch and proteins that may take a little longer to be effective. A good part of the home dishwasher cycle is soaking/rinsing. Most modern dishwashers have a quick cycle that skips this step mostly and only takes about 30 minutes and it's useful if you have to wash a full load right after a meal. The professional dishwasher skips it completely and just goes at it with high water pressure and agressive detergent.",
"Did dishes in a big old age home when I was a teenager. The dishwashers operate at such high temps that even if you end up with something left on the dish, it's sterile. Recently helped at a soup kitchen.... naturally, with my experience from many years ago I helped with the dishes. They had a small unit that washed the dishes after initial hand rinse and it worked really well. Guy who did it all the time said he wished he had that unit at home. But I imagine it would be quite expensive. Plus it was designed for a single rack of dishes at one time. Home units are designed with practicality in mind. You load it up over a few hours then run it. Not very convenient if you have to fill a single rack then run it, then dry your stuff by hand. The old Hobart unit we used at the old ago home was a beast. Dishes came out so hot you'd practically burn your hands when taking them out of the racks. Everybody slags dishwashing as a job but I didn't mind it. We had union pay and it was OK. Certainly had a lot worse jobs that that when I was young. Washing dishes we just worked fast and you're like on an assembly line. It's mindless work but you still have to do it right and you have to do it fast. Besides, most work becomes brain stem function after a while. People just don't like to admit this about their work so they say things like, \"Yeah, every day is different\". Honestly....if every day was so different you wouldn't be happy because you wouldn't become any good at your job."
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7chjz6 | Where did all the sand in the desert come from? | Other | explainlikeimfive | {
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"Essentially eroded rock. The ice age melted into oceans, oceans dried up and the wind eroded the rock bed into sand."
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7chqxn | Why is marine life clustered around reefs so colourful when marine life in general is typically dull (silver, grey, blue etc) | Biology | explainlikeimfive | {
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"Best answer I can give, it is because there are places to hide. When you are brightly colored you make sure to show off for potential mates. But you are also more visible to predators. Around the reef, there are many other places to hide if a predator were to come through. Out in the open ocean, if you can't be seen easily, you have a better chance of being passed over. If you are a brightly colored fish out in the middle of nowhere, you will be noticed much faster.",
"It's camouflage. Water absorbs light-color wavelengths, turning most of them to black and white. (EDIT: It's actually more like blue and white, since \"blue\" is the last wavelength to be absorbed by the water.) So the fish do not actually see the bright colors that we see on fish (and divers don't see them either unless the fish are close to the surface or we bring our own light to illuminate them). In monochrome, the colors form disruptive patterns that hide the fish against the background of rocks, corals, and shadows. (That's why if you look at a black and white photo of a reef, it's hard to see the fish.)",
"One theory for this \"peacocking\" is that its typically seen were there is an abundance of life and survival is easier. In these scenarios survival of the sexiest often shapes evolution more than survival of the fittest. In the open ocean the duller more camoflauged critters are the only ones who survive long enough to reproduce. But where the environment is more forgiving and being colorful doesn't get you offed immediately, the fish that fornicates the most is the evolutionary winner. So they reproduce more successfully by being very noticeable to their mates even if it puts them at more risk of predation. I think this is the stronger theory as fish have been evolving eyes to see underwater longer than we have been evolving them to see in open air, so many can see color pretty well and some see more color wavelengths and even bends in light thay we can't see. Also, reefs don't really exist too much deeper than 50 ft where you would start to see more of the colors being filtered out."
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7chv8a | Why can gravity bend light even though light has no mass? | Physics | explainlikeimfive | {
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"Gravity bends the *space*, not the light. Light just takes a straight course. If that course is over curved space, the light \"bends\"."
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7chxcb | How does matter transform into energy, visually speaking? | Physics | explainlikeimfive | {
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"Well if you split an atom intramolecular bonds change from matter to energy. So what would it look like visually is a nuclear explosion. The sun would be a good example of energy turning into matter actually, also a huge explosion. Due to its nature I don't think anyone has an actual visual representation of the transformation, there isn't a stable intermediate so its matter, then its just energy, like electrons switching between energy levels.",
"Everything is energy. Mass is simply the energy that's contained within a system regardless of what you do. It doesn't matter who is viewing the system, there's a minimum amount of energy that simply will always be there. A baseball has a certain amount of energy. It's got the nuclear energy in all it's atoms, the chemical energy in all the binding between atoms, thermal energy in the random motion if the atoms, and kinetic energy in how fast the ball as a whole is moving. It's \"mass\" is nuclear, chemical, thermal energy combined, the internal energies. However, the thermal energy and chemical energy are insignificant next to the nuclear energy. If a professional baseball player through the ball, relative to you standing there it's gained a lot of energy. Does this energy mean it gained mass? Well, it depends if everyone sees it with that energy, and the answer is no. If you were in a car traveling along side the ball, it's not moving. It has no kinetic energy. There is always a viewpoint you can take where an object has zero motion, zero kinetic energy. Therefore, kinetic energy isn't mass. And whatever energy is left then is the mass. The energy internal to it. Now, I said thermal energy contributes (a trivial amount) to mass of a ball. But if thermal energy is just random kinetic motion of the atoms, how does that work? Because the mass of a baseball is the mass of the entire system staying together, that is the ball. It's not the mass of the individual atoms summed up. Energy confined to a system becomes mass to that system. An atom moving left and another moving right within a ball in still there even if the ball is stationary, therefore that kinetic energy is part of the ball's mass. That means if I took a mirrored box and weighed it, and then filled it with a lot of light to continually bounce around inside and wieght it again, the box would weigh more. Add light, completely massless pure energy, to a box will make the box have more mass. Just as adding pure kinetic energy in the forming of moving atoms (heat) made the baseball slightly heavier. So what about converting matter into energy? Well, what is matter? It has mass and it's made of atoms. Atoms are made of electrons, protons, and neutrons. Protons and neutrons contribute the vast majority of the mass to an atom. What are protons and neutrons? They are three even smaller particles called quarks held together. What is the mass of a quark? Only a tiny insignificant fraction of the mass of a proton or neutron. 3x the mass of a quark isn't even close to the mass of a proton or neutron. What does that mean, where is the rest of the mass of an atom, of all matter, coming from? The vast majority of the mass of matter isn't actually the mass of what's it's made of, it's energy. Nuclear binding energy is the vast majority of the mass of matter. It's as much pure energy as light it. And just like light is made of a massless entity called a photon, the nuclear energy is made of a massless entity called a gluon (literally because it glues things together). It manifests itself as mass only because it's confined within an atom, and confirmed energy is mass. So what happens in a nuclear reaction and mass is converted to energy that we always hear about? Well, the subatomic particles rearrange themselves. This rearrangement has slight less nuclear binding energy so it has slightly less mass. Where did the mass go? It was converted to energy that was no longer confined to the atoms, such as light or kinetic energy. And hence, the atom lost mass. All the same particles are still there though. It's the same for chemical reactions too. In this case it's just electrons rearranging themselves, changing the energy in the chemical bonds, and therefore changing the mass too. Just not as much of a change in energy as a nuclear reaction, so less of a change in mass. That said, there are some things with fundamental mass. An electron has mass. It's not made of anything smaller, it simply has mass. That is, it has energy even if you stop it from moving. Where this mass comes from is a little complicated. Nonetheless, it isn't fixed. You can annihilate an electron (using its positively charged cousin the positron), and they both vanish into light. So why doesn't light have mass? There's no way to view light in a way that it has a fixed minimum energy. If you have an electron whizzing by, you can always move the same speed as it and see it with zero kinetic energy. With light, you can't do this. If you move closer and closer to the speed of light to chase a particle of light, it simply gets more and more red. Less energy, until it essentially vanishes with zero energy. Very crudely, light is just kinetic energy. You can't stop it and still have energy left sitting there."
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7chyey | How does caffeine works? And how the effects stack up by taking bigger doses? | Biology | explainlikeimfive | {
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"The cells in our body have various adenosine receptors that normally bind with adenosine and this acts like a car brake for them. The more adenosine binds to its receptors, the more cells slow down. Caffeine works through blocking these receptors. So the cell basically thinks all the receptors are free, but in fact adenosine cant bind because caffeine prevents them. And because most of the adenosine receptors are in the brain, we get more alert and our cognitive functions increase for a while. Also our heart speeds up, some hormones like adrenaline get released etc. Long story short, caffeine acts like a rock under the brake pedal, even if you press the pedal the car wont slow down like it used to be. Taking bigger doses are like changing the size of the rock, the bigger it is the more it will block."
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7chz47 | What happens to your body but more specifically your brain when you are shot in the head? | Biology | explainlikeimfive | {
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"The bullet travels through your brain faster than the speed at which your tissues tear. This means that it's actually pushing tissues out of the way, stretching them beyond their breaking points. When high velocity long arms are responsible, bullets traveling at thousands of feet per second will exit your body before your tissues have a chance to rip. The ability to process information and solve problems? All gone when the bullet shoves its way through your prefrontal cortex. Your ability to index memories? Gone. In the bullet's wake, a long temporary cavity is left. When the tearing finally does happen, your tissues will snap back toward the initial opening and overshoot their original position. You know that back and forth thing that happens when you kick one of those springy door stops? Well that's what your tissues do when the shock waves kick them. Your brain stops functioning almost immediately. In just a fraction of a second, you're gone. Edit: TL;DR ur ded"
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7cibw2 | How a box fan can cause an FM station to be heard in a room (without a radio) whenever it's running? | Physics | explainlikeimfive | {
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"The box fan must be vibrating at the perfect frequency to pick up and amplify the radio frequency. It's a process called demodulation I wanted to add some to this now that I have some time. The radio waves that are in the air all around us are made of two parts, the signal wave and carrier wave. The signal wave contains the information, in the case of radio that would be the sounds you hear. The carrier wave is what we call the channel take the channel 91.4 FM which is broadcast on 91.4 megahertz. That means it is vibrating at 91 million times per second. A radio works by vibrating at the same rate as the signal. Once the receiver in the radio is vibrating at 91.4 Mhz it can then \"read\" the signal wave. FM (frequency modulation) is pretty tricky compared to AM (amplitude modulation) so more than likely your fan is picking up an AM signal. Edit: got some free time and decided to add some information. I'm no expert but I've learned about radio waves and demodulation in an industrial electronics course."
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7cim7u | why is it easier to balance on a bike while going faster rather than slower? | Physics | explainlikeimfive | {
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"NOT because of gyroscopic force, as many people think... If you look at a bicycle, where the front wheel attaches is further forward than the head tube (where the fork attaches to the rest of the bike). This is an important design feature, because it means that when the bike veers to one side, the front wheel has a tendency to turn to that side, causing the bike to turn instead of fall over. It's a sort of auto-correction: even if you just shove a bicycle forward with no one steering it fast enough, the bike may turn, but will resist falling until it slows down to the point that it makes too drastic of an adjustment and falls over."
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7cinnr | Beveridge Model vs Single Payer system | On the Wikipedia page for [Single Payer Healthcare]( URL_0 ), the [single payer section]( URL_0 #Regions_with_single-payer_systems) and the ["Beveridge Model" section]( URL_0 #Regions_with_.27Beveridge_Model.27_systems) both have different countries listed, but aren't they synonymous? What's the different between a Beveridge Model and a Single Payer Model? | Economics | explainlikeimfive | {
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"The answer to your question is written in black and white in the links you provided. From the Beveridge Model section: > The term 'Scandinavian model' of health care systems has a few common features: largely public providers, limited private health coverage, and regionally-run, devolved systems with limited involvement from the central government.. Due to this third characteristic, they can also be argued to be single-payer only on a regional level, or to be multi-payer systems, as opposed to the nationally run health coverage found in Canada, Taiwan and South Korea."
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7cisku | Why does it snow at sea level in America, but not at sea level in Australia? | It snows in New York City during Winter, and they are sitting at sea level, yet when Winter comes to Australia, it only snows at the highest parts of the country, and never anywhere near sea level. | Other | explainlikeimfive | {
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"Australia is 25.2744° S, sitting at the Tropic of Capricorn, while New York is 40.7128° N, far away from the Tropic of Cancer, which is in México. Since New York is further away from the Equator, on average, it's colder than Australia. Now, why places at the Equator tend to be hotter than those at the Poles? The Equator is closer to the Sun, but that only plays a minor role in this. If you concentrate sunlight on a piece of paper using a magnifying glass it will burn, right? That's because the sunlight is focused on a small area. If you rotate the paper so the light reaches at a 45° angle, you'll notice it takes more time to burn. That's because the same amount of light is concentrated on a broader area. Now try rotating it 80°. You can't burn the paper now. That's the same that happens on Earth. The Equator is perpendicular (mostly) to the sunlight, while the Poles are parallel. This is also why the Sun doesn't bother as much during sunrise and sunset.",
"Look at the map and look at the latitudes of New York and Australia. The closer you get to the poles (higher latitudes), the colder its get. Then look at the seacurrents nearby if they're warm or cold. You could look to New York it's get very cold there. The current there is cold. You look at London it's not getting so cold there. The current there is warm. Thats why Murmansk is not really freezing in winter. That makes for warm or cold for the most part. And global warming of course.",
"Whether it snows or not doesn't depend where you are. It depends on the temperature. In NYC the temperature is below 32 degrees F sometimes. So it snows. In Australia, it may be below 32 degrees F but there is no precipitation above you (clear skies) or you area never reaches 32 degrees F. As you getting higher and higher into the atmosphere, it gets colder and colder. That's why most really tall mountains have snow on them, a) the temp around them at this altitude is below 32 and b) they are physically in the clouds, clouds are just water vapor. That water vapor turns into snow or ice"
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7cix06 | What is an autonomous province? | All I know about them is that Kosovo was one and Vojvodina is one. What are they? A middle ground between countries and normal provinces? | Other | explainlikeimfive | {
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"A province is typically not a country or a state, but a region governed by some other authority, like a child not yet old enough to make its own decisions. An autonomous province is an area that governs itself while still operating under some other authority, like a teenager who decides when and where they go but could still be grounded by the parent if they make bad choices.",
"I'm Chinese, so I will explain with Hongkong. Also I'm just explaining what I'm told and it may not be the truth as politics is always complicated. And also this might not be how Kosovo and Vojvodina operates. I don't know how it's regarded internationally. In Mainland China, Hongkong is regarded as a \"self-governed district\" (or autonomous city as you might call it) of China. This means on paper, Chinese government would generally not interfere with Hongkong government's operation or decision. While officially, Hongkong is still part of China. The reason is, China is a socialist/communist country. Previously, Hongkong was a British colony and adopted capitalism. When hongkong was returned to China in 1997, Chinese goverment decided that it was the best to keep capitalism in Hongkong so that it doesn't cause drastic change for them. So it turned into a autonomous city operating under a different ideology. As you can see in the last couple years, Chinese government seems to be interfering in some way. So the main government body is definitely in control but choose not to. When interfering does happen, it probably wouldn't be well received by the locals."
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7cixy5 | Why do we shake our hands when we hurt them but no shake other parts of our bodies when we hurt them? | Biology | explainlikeimfive | {
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"It also has to do with the nerves in that area. If you shake your hand when it gets hurt it activates the nerves in the hands and your brain can’t really differentiate between pain and the shaking sensation. Same reason we press on an injury like if you stub your toe or hit the side of a table with your hip."
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7cj1zj | How do illnesses cause blisters similar to the ones caused from friction? | Biology | explainlikeimfive | {
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"Blisters form when the topmost layer of the skin gets detached from the underlying tissue. The gap then fills with liquid. The skin can get detached from friction (a mechanical force) It can also come off due to heat, which breaks down the proteins that keep it together. A third way for this to happen is due to a disease where you dont make the right protein, so it detatches with little force. A fourth way would be an infection, which causes inflamation and protein breakdown. In this case the fluid inside the blister will have a different composition (pus)"
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7cj2t7 | What are the industry benefits for 'blue laws?' | Hi ELI5: I live in Indiana, where it is illegal to buy alcohol on Sunday throughout the state. Some counties are dry counties, but the entire state goes 'dry' for Sunday. When I was younger, I thought this was due to pressure from religious groups. I've come to understand (perhaps wrongly, but...) that this is actually due to pressure from liquor store owners? Why would an industry lobby against attempts to let it sell its products more often? What is the benefit to the liquor stores if **no one** can sell liquor on Sundays? | Economics | explainlikeimfive | {
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"Say I'm the proprietor of a liquor store, and I want to take Sunday off. But I don't want to lose business to my competitor should he decide to work on Sunday. I have a great idea, let's force him to take Sunday off as well! Notably, my competitor can be thinking the same thing, but with the roles reversed. So you collude with your competition using the state (or county) as the mediator and enforcer. Since collusion without government mediation is both illegal and hard to enforce, this is a great deal for you. (But my experience from the next state north, I think your understanding is wrong. The strictness of the blue laws correlated with the county's religiosity, not with its liquor-store-ownerosity.)",
"Hello fellow Hoosier! For a time I worked in one of our state's many alcohol manufacturing facilities so my experience may help answer your question. There are now a multitude of reasons we cannot buy alcohol on Sundays. In addition to holding strong to certain religious beliefs, there is also a belief among some members of the population and law enforcement agencies that increased availability of alcohol is a likely contributor to instances of DUI, domestic disputes, drug use, etc. Now, this is in a way non-sensical because as a rational human being (and one who may be prone to forget to stock up on Saturdays) you may say \"well we can get it at any restaurant and bar.\" And you would be entirely correct. This, however, seems to be the first line of defense against Sunday sales and one that has in the past been a shutdown to the argument in favor of Sunday sales. Another avenue that you might not have thought about is the various manufacturing facilities (i.e. wineries, breweries, and distilleries) themselves advocating against Sunday sales. A \"loophole\" in the Indiana laws allows breweries, wineries, and distilleries to sell their wares for carry-out on Sundays. Why would they relinquish an exclusive privilege (not to mention one that brings in a higher dollar-per-unit profit than traditional sales) and give it to the package liquor stores and grocery stores? This argument too may be going by the wayside as brewery and distillery guilds begin to lobby state lawmakers for Sunday sales. Why, after all, would they limit themselves to only one point-of-sale when they could have many, many points-of-sale? This point-of-sale consideration obviously works better for the bigger, established brands who have bigger marketing budgets (like Sun King), but does not tend to favor smaller manufacturers who would take a smaller piece of the proverbial Sunday-sale pie. The Sunday carry-out ban has been brought up for consideration in the Indiana legislature for several years running. It would not be surprising if it passed either this upcoming legislative session or the next."
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7cj6sl | When going over a hill in a car, what causes that fluttery feeling in your stomach? | My daughter asked me this question while we were driving earlier today and I was completely stumped. | Physics | explainlikeimfive | {
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"That's your stomach jumping up in your abdomen. You might be (hopefully) strapped in with a seatbelt, but your organs as such aren't. They can move a little bit when you're in a car going over a hill, and that's all it is.",
"Inertia. Your body wants to keep going in the direction that the car was headed (upward, up the hill) and as you round the hill, gravity is now pulling you in a new direction than your insides were headed. What you're experiencing is basically a drop in G-force. A brief moment of lower gravity that causes your stomach and organs to float around a bit before they succumb to gravity and it pulls you back down. The principle is pretty similar to how [weightless flights]( URL_0 ) are done."
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7cj8dx | What are some examples of things that would be acceptable under Thomas Hobbes' system which wouldn't be allowed under Locke's? | Citizens can rise up against Hobbes' absolutist leader if they don't feel protected, but still Locke focuses on general freedom and law yet is still ok with a monarch, for example. But I was just wondering, what are a few practical examples of the difference in everyday life in each regime. | Other | explainlikeimfive | {
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"Both are supporters of a strong central government, but where Hobbes' leviathan describes the reasons for forming and philosophy of maintaining an absolute government (not necessarily a single person), Locke's work focuses on a religious rational for killing a particular sort of corrupt king. Hobbes has strong feelings about rebellion, but he also includes a lot of advice for the leviathan to make revolution/rebellion less likely. To avoid the state of nature (which Hobbes considers to be the *worst* thing ever), a leviathan must be able to protect its people from things like foreign invasion, and it must be able to protect itself from rebellion. Hobbes recommends the leviathan behave in various ways to make rebellion less likely (basic freedoms, consistent and fair application of the law, yadda yadda), and he recommends absolute brutality in shutting down any rebellion that does crop up. Locke on the other hand agreed with the merits of a strong central government, but in his case the King was amassing personal riches at the cost of the taxpayer. Locke equates it to highway robbery and moves from there to how government should be limited. The life of the average joe is pretty similar, but where Hobbes instructs the leader(s) on how to create a strong and successful government, Locke instructs the citizens on what kinds of governments need to be torn down. Edit to actually answer your question: there is a ton of overlap (if not complete overlap) between the various lifestyles that would be acceptable under leviathan and the central government as envisioned by Locke. The difference is that where Hobbes says, \"The citizens might rebel if you do this. They're not allowed to, and you should crush them ASAP, but they might rebel, so don't do this,\" Locke responds, \"If the government does these things, you have a god-given duty to rise up and fix it.\""
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7cjase | Why is alligator tail meat as white as (if not whiter than) poultry—i.e. chicken breast? Is it similar muscle? What makes it that way? | Biology | explainlikeimfive | {
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"Light meat is a meat with smaller amounts of myoglobin than dark meat. Myoglobin is related to hemoglobin, which is the red part of your blood. Both molecules use iron to hold on to oxygen. Dark muscles with myoglobin are used for endurance. This is why leg muscles on chicken are dark meat...chickens run around all day, but fly in short bursts. Birds that fly steadily for long periods of time have dark breastmeat. You can see this in fish, too. Tuna, which swim constantly their whole lives, have dark meat, while flounder, which spend most of the day lying on the bottom, have light meat. Alligators spend most of the day hanging around rather than actively swimming, but they need bursts of power from their tail to surge forward in order to attack prey. So they have light meat back there. But what about mammals, you ask? Mammals differ from most birds and reptiles because they tend to have light and dark muscle fibers mixed together in the same muscle. So you get \"red meat\" instead of light vs dark",
"it's not. it's our modern farming techniques that make chicken that boldly beige (or whatever you call it) colored. Purdue got famous/big by selling chickens it claimed were more healthful because it had a bolder color, that is you could see it was more healthy. He achieved this by feeding the birds marigolds; the carotenoids in the petals got absorbed into the fatty tissues/tissues in general and turned the meat a stronger, darker hue. Eventually this became standard industry practice In general the more wild forage an animal is allowed to eat, the more color compounds it eats which change it's meat. If you take chickens and just feed them without letting them root around, I've been told the meat is pretty damned white. In the same theme of color compounds , alligator tail meat is extremely lean (color compounds are fat soluble)"
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7cjgjv | How do Therapist/Psychologist treat mental illnesses and disorders? | For example: Someone with extreme anger issues most likely have problems relating to chemical imbalances in their brain. Do mental doctors usually prescribe pills mainly? I can't see talking as a way to simply solve problems like these since it is like putting a band-aid in an open wound that requires stitches or surgery and expecting it to heal on its own. | Other | explainlikeimfive | {
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"One of the weird things about healthcare is that \"yes/no\" questions usually beat \"why\" questions. If something is proven to work, but we don't know why, we shrug and keep doing it. Lots of people get Botox injections for migraine, which works really well but is a complete mystery. So, when it comes to helping people with any given mental problem, the question isn't \"Should it work?\" but \"Does it work?\" In this case, it's worth remembering that brains are supposed to change depending on what they do. If brain cells didn't make new connections based on input and forget old ones that don't get used, we wouldn't be able to learn or adapt to anything. You learned to speak and walk because you did things and your brain kept rewiring. You remember what you ate for breakfast because your brain changed a little bit. Sure, it's technically true that any brain problem is sort of chemical, but so is any heart or lung or skin problem. Humans are 100% made of chemicals. The \"chemical imbalance\" business was peddled hard by drug companies, but doesn't have much of a role in modern psychiatry. So, let's pretend a patient comes in with major depression. The odds are good they have a lot of hard, automatic negative thoughts that set off, worsen, or reinforce their persistent low mood. They've stopped doing things that might make them feel better, like being with people or staying active. Different forms of therapy focus on challenging those thoughts and replacing them with more helpful ones, or doing things that make you feel better. And it works. A solid body of evidence suggests that talk therapy is about as effective as standard antidepressants for most major depression, and likely better for not-quite-major depression. When it comes to treating mental disorders with therapy, medication, or both, it really depends on the problem. Medication works better for schizophrenia, therapy works better for social anxiety, and the combination is often a reasonable bet."
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7cjnzz | Why is having an overbite a problem? | Are there any actual medical issues or is it just cosmetic? | Biology | explainlikeimfive | {
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"My understanding is that a person with a pronounced overbite will have issues with teeth growing incorrectly and or accelerated wear i.e. grinding",
"Having a poor bite makes eating more difficult. It can also result in speech issues. In extreme cases, if your teeth aren't making contact with the ones on the other side, they can eventually work loose and fall out.",
"Not an overbite here, but an underbite. I was set to have corrective surgery, but didn't for reasons. The surgeon explained that if I didn't have my bite fixed, later in life I could develop severe migraines, and that my teeth would wear down quicker, and in weird spots. He said the eating bit was personal preference, and to be honest, I don't tear through my food like normal, it's more me ripping it apart, because my teeth don't do the scissor action normal teeth do. It doesn't bother me though. I haven't had any migraines yet, although my jaw does pop and sometimes get stuck shut/open."
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7cjqtg | The final scene in Trading Places. | Economics | explainlikeimfive | {
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"Past threads on this: URL_1 Older thread on this: URL_0 My Answer from older thread: /u/Pobody is right, but to clarify a bit, here's the stages (numbers are made up, just to illustrate): 1.) **That morning** - The Dukes have a fake crop report, saying that there is an orange shortage. They take out a short term loan so that they can buy orange futures at the current price. Say the price is $10, because people are unsure of whether there will be a shortage. 2.) **That afternoon** - Murphy and Akroyd show up. The price now is at $15, because the Dukes, and many others following the Dukes, have been buying all day, driving up the price. Murphy and Akroyd start to SELL. They don't own any shares (or own just a few), but that's alright, since they don't have to \"settle up,\" meaning actually give the shares they \"have\" to the person buying, until the end of the day. 3.) **Just before the bell** - the crop report comes out. There is no orange shortage. Now, the price drops from $15 to $5, since everyone knows there are too many oranges, and so everyone starts selling. Once the price gets low enough, Murphy and Akroyd start to buy, which is easy, since everyone else is trying to sell. They buy enough to cover the sales they made earlier in the day, and pocket the difference (15-5 = $10 per share). The Dukes, on the other hand, are stuck. They sell what they can, but every sale is a loss. 4.) **after the bell** - the Dukes haven't made enough to cover their short term loans. They are bankrupt. 5.) **way after the bell** - Murphy's unrelated, identical twin, a wealthy African Prince, happens upon the Dukes living on the street, gifts them tens of thousands of dollars. they are back."
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7cjs9i | Why do some cell phones have area codes different from the geographical area in which they were purchased? | For example, I live in a suburb of Minneapolis where the area code is 952. But my cell phone's area code is 612 - the area code for Minneapolis city proper - even though I purchased it in the suburbs where the area code is 952. | Technology | explainlikeimfive | {
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"Phone carriers are assigned numbers in blocks. For example Verizon with have 612-512-0001 through 612-512-9999 to assign to accounts and AT & T will have a different set of numbers. In major metro areas there are often multiple area codes simply because one got used up. It's not really downtown v. the burbs but that's how it pans out for practical reasons. All the established numbers are on the old area code and downtown. All the new numbers area from newer areas."
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7cjt6e | Why do we forget bad memories or long periods of trauma? | I have forgotten some of the most traumatic details of my life, things that you'd think would be burned into the brain. I struggle trying to recount things to my therapist and it frustrates me and makes me almost believe i'm incorrect when i'm not. Why is this? | Biology | explainlikeimfive | {
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"With PTSD specifically, it has to do with how the brain fails to process a traumatic event in the first place. When we experience threat, the “fight or flight” stress cycle kicks in. The limbic system is highly involved in this process, which also has the nervous system flooded with stress hormones like adrenaline. What makes trauma a unique occurrence is the actual failure of “fight or flight” - if neither course of action is deemed safe, a special emergency function gets triggered which results in something called tonic immobility, also known as freezing. This is the doe in the headlights reaction. During tonic immobility, the limbic system is completely overcome with a mixture of hormones that effectively debilitate all other processes. However, the limbic system is responsible for our conception of time. This is why trauma survivors almost universally report a sense of time “slowing down” or “time standing still” during the event. It is also why the memory of the event is often lost: the brain is literally unable to “file it away” as an event located in the past because the part of the brain that can understand past/present/future is so tied up. Intuitively, this explains two of the most common yet seemingly contradictory symptoms of PTSD: we do not store memory in the typical sense and therefore suffer from amnesia of the actual event; but simultaneously, *bodily* feelings from the event “linger” in the nervous system because they were not processed as past at the time. This is why a trauma survivor, when triggered, quite literally re-experiences the trauma all over again; the neurological signature of the event is still left intact following a tonic immobility response. Source: science learned mostly from The Body Remembers by Babette Rothschild (highly recommended btw, if you’re willing to wade through a little bit of terminology) also 2+ years of PTSD treatment and therapy Hope you’re okay OP!",
"This is a process known as \"[dissociative amnesia]( URL_0 )\" — that is, your mind is actively suppressing your recall of these memories in order to avoid experiencing the trauma again. A good strategy for working with repression is propping up the details on either side, and hopefully the memories will return. Alternatively, sometimes [the memories are never coded into long-term memory at all]( URL_1 ), due to their nature. This type of trauma usually resurfaces as PTSD once your mind finally writes the trauma into long-term memory. You can't recall memories that aren't in there to begin with.",
"I am the opposite. I remember traumatic events but find it hard to remember the happy moments",
"Not sure - I have found the complete opposite. The memories don't fade. Instead, I remember something else just about every day. Just adds to the pile."
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7cjugw | Can a flu shot make you feel sick? | Biology | explainlikeimfive | {
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"Yes. Headache, fever, nausea, and muscle aches are common side effects of flu vaccines. They are usually mild and go away by themselves after a day or two.",
"Yes, a flu shot is basically an injection of the flu itself but in a weaker condition so that your body can fight it and build the necessary chemical compounds to fight the flu if your immune system sees the flu again."
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7cjwo7 | Why is it that batteries don't go dead when you connect their ends with wire? | I'm trying to understand Ohm's law and resistance behind circuits. If you take a battery and connect its two ends using a copper wire without any resistance (like a light bulb), your resistance is around zero. Because the voltage is constant, your current going through the wire seems to be absurdly high, which would result in a massive flow of electrons from one end of the battery to the other. So what prevents batteries from going dead if you do this? Because I'm still pretty new to circuits, please forgive me if my question wasn't clear enough. Edit: Also, is "technology" the right flair? I'm still kind of new to this sub. | Technology | explainlikeimfive | {
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"The point is, resistance isn't around zero. A battery might have 2500mAh capacity at 1.5V. The battery itself has a resistance of about 0.2 ohms. A wire connecting both terminals might have about 0.002 ohms. According to Ohm's law, this setup will draw around 7.5 amps, or 7500mA. A 2500mAh battery can deliver 2500mA for one hour, or 7500mA for 1/3 of an hour. So, if the circuit doesn't catch fire or melt it will manage to deliver this current for about 20minutes before it runs dead.",
"Nothing. The battery will go dead. Rather quickly. Not instantaneously, though, because, as you said, the voltage can only go so high. More likely, though, your battery is going to overheat and, if it's a LiPO, probably explode. So it won't have time to empty completely. But yeah, if that didn't happen it would go dead."
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7cjwu2 | Why do cacti always seem to have spikes or barbs? | I get that it is for protection, but why specifically cacti? Is that what defines the family Cactaceae? | Biology | explainlikeimfive | {
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"Because the cacti have adapted to live in harsh and hot environments, they evolved into spikes. Normally those spikes are considered as leaves of the plant. Having a classical shaped leaf would cause cacti to loose excessive amounts of water in hot and arid climates via evaporation so they evolved into spikes in order to decrease the surface area and water loss. Also it contributes as a defence mechanism to outside threats so thats an advantage too."
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7cjz26 | What are “knots”? | Other | explainlikeimfive | {
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"A knot is a unit of speed. It's similar to miles per hour except instead of using statute miles (the mile you're probably more familiar with which is 5280 feet) it uses nautical miles which are roughly 15% longer than statute miles. The reason nautical miles are used is because a nautical mile is exactly one minute of latitude so it relates to travelling by sea (and air) more easily. It's important to note that the term knot means nautical miles per hour so you would never say a ship is travelling at 25 knots per hour. You would simply say a ship is travelling at 25 knots. Also interesting to note that commercial airliners (and in fact about 99 percent of planes) measure speed in knots. Older planes used to use mph but that's pretty much long gone now.",
"Knots is a measure of speed for a ship traveling a nautical mile per hour. Sailors user to throw a rope with a board tied to it over the stern of a ship, flip a sand timer and count the knots tied in the rope that passed within the 30 second sand timer to figure out how many knots they were going."
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7cjz8y | Why do you feel sick and not hungry when you haven't eaten | Biology | explainlikeimfive | {
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"After years of dealing with an illness, I can say that it's the buildup of gases in the stomach that aren't being pushed down by more food. Chewing gum and burping is a quick fix. If you haven't eaten in a whole day or two, your blood sugar really levels out and you don't feel the urge to constantly consume at regular intervals anymore. During this period, the blood sugar is pretty low, and you start to feel dizzy and confused on top of that.",
"It’s basically your body going “fuck this, they obviously aren’t going to eat, why make them hungry?” The basis is there’s really no point in inhibiting the search of food by making you feel hungry"
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7ck0ea | Why are apartment buildings still using call boxes that look like they were made in the 80s? | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"Because they don't want to spend money to replace them with something newer? If it still \"works\" then why spend a few grand getting a new system?"
],
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7ck0or | Where do all the leaves eventually go after Autumn? | Biology | explainlikeimfive | {
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"They get broken down by the elements, bugs, fungi, and bacteria and turned into soil. The dirt under your feet is just a mix of minerals and dead stuff.",
"They get continually broken down by mechanical force (wind, rain, etc) to smaller bits or by living forces (bugs, fungi, etc) until they're tiny bits of matter. That matter eventually becomes a very thin layer of soil. Through of years of this cycle, we get [soil layers]( URL_0 ) that you've seen in text books. After thousands of years, ancient items will be buried and that's why we find evidence of ancient people and animals underground.",
"In the wild they just pile up and eventually rot away into mud. It can take some time for this to occur, and the floor of a largely deciduous forest can be pretty well coated with discarded leaves from the last few years. On your lawn they'll get mulched by the lawnmower in spring if you don't rake them up."
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7ckc3s | Why people think gentrification of an urban area is a bad thing | Other | explainlikeimfive | {
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"Basically people think it's bad because as a low income area becomes \"gentrified\" More higher end shops and stores and people move in driving the prices and costs up (rent etc) forcing the people who lived there already out because they can no longer afford it.",
"The \"reasonable\" argument that gentrification is bad comes in two flavors. The first is a sort of \"localism\" argument. This is the argument that the characters in the musical Rent are employing: that areas that become wealthier tend to become the same type of area, without any of the local quirks and interests. So the five individual coffee shops become five identical Starbucks, and all the interesting characters are pushed out of the neighborhood to be replaced by interchangeable investment bankers. The second is a sort of \"fairness\" or community argument. The idea here is that gentrification brings higher rents which benefits land owners, but not the poorer residents who live in the neighborhoods. And, those poorer residents don't just get moved back incrementally, but are forced piecemeal to resettle in shittier area farther from jobs/services than their current locations, and now separated from the friends and communities that they and possible their parents and grandparents and so on called home. Of course, your mileage may vary on these arguments, but these are the two that are the most non-ridiculous."
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7ckdcu | Why are we able to perform tasks, such as filling a cup of water without looking at it? Is it a learnt experience, or is simply knowing the sound of a full sounding cup enough? | Biology | explainlikeimfive | {
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"It's you brain using a collective sensory input to deliver a particular muscular output, this is more commonly known as muscle memory and used extensively by musicians when the learn a particular musical passage or technique. Once the right sequence is perfected, repetion creates muscle memory so that they no longer need to apply the same level of concentration as when the task was first attempted. The brain is capable of doing this for a wide variety of tasks, other examples are driving a car, riding a bicycle and so on."
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7ckmcx | is static electricity harmful to our bodies? | I work in a paper mill and there is crazy static build up. I’ve seen guys dropped to their knees after the loud crack of getting zapped. I’m wondering if it’s more just an inconvenience or if there are long term side effects from continuous zaps. Thanks! | Biology | explainlikeimfive | {
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"Static electricity isn't dangerous. Dynamic electricity is. It depends on how much energy these guys are absorbing. This question can really only be answered by a doctor who does research in this area. How big is your plant on safety? Have you talked to OSHA? The body of the machines should be grounded to avoid these discharges. I've never designed a paper mill before, but it seems like a safety hazard."
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7ckom4 | How come multiple wireless providers can all claim they have the best speeds? Isn’t wireless connectivity and accessibility something that can be objectively measured and ranked? | Technology | explainlikeimfive | {
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"They use different metrics to determine what is \"best\", because \"best\" is a subjective term in marketing. They could be referring to \"the best wireless speed compared to two other local service providers that haven't upgraded their equipment in twenty years\", or \"the best wireless speed available in Sedona, Arizona.\" You have to read the fine print to determine what their metric is. When it's all big-brand companies, they often use metrics gathered from different sources. For example, Verizon might use URL_0 to determine \"best speed\", but they also might throttle their speeds outside of the URL_0 domain; whereas Comcast might use average speed for the top 10 most popular websites.",
"Technically, not to get afoul of the FCC, all they need is to be the best in one small area to be able to make the claim. So, if they are the fastest wireless provider in Podunk, USA where they are the only one, then they can make the claim. It is the same as all the truck companies saying they are #1 selling truck in the US. It is all in the fine print, which no one likes to read.",
"You would think that but not really since there are a lot of metrics out there as to what they mean. Those claims are very broad and can refer to any number of metrics. Not to mention that advertising has a lot of wiggle room for things like puffery.",
"Speeds vary based on location and congestion so where, when, and how it is measured makes a big difference. They only need one test basically to point at to show they are fastest. One method providers will use is they will perform their tests immediate after launching an upgrade to their system... but before most of their userbase gets the update to actually utilize it. That way, they can get \"optimal\" speeds that are crazy fast, but once a million people are using it, it slows down a lot.",
"Let's say three cars are being tested to see which one is the fastest by their manufacturers. Manufacturer A tests all 3 cars and uses the speed displayed on the speedometer, this result lets them say their car is the fastest. Manufacturer B tests all 3 cars and uses GPS data to compute the speed, this result can let them say their car is the fastest. Manufacturer C tests all 3 cars and uses a speed-trap setup to compute the speed, this result can let them say their car is the fastest. By choosing the way they collect data, or the location they collect data, companies can manipulate the results of a 'see who's fastest' test to ensure they win."
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7ckqhp | How does our brain subconsciously pick a laugh to use and why does it change over time? | Biology | explainlikeimfive | {
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"I would say this is as much social as it is biological. There are always social factors determining how one ought to laugh in a given situation, and social sanctions (\"his laugh is so weird\") are in place to punish and discourage laughs that are outside what a culture says is okay at any moment. There's a biological response to laugh in certain situations as ways to defuse fear, or to express emotion to listeners, etc. but HOW someone laughs is social, even moment to moment (\"God that was funny. Oh man am I really laughing this loud during Aunt Janet's fancy dinner party? That's so awkward, but i can't help it. Everyone is looking at me! Ah fuck it.\" =like 7 different laughs). Ultimately, our brain is very very good at picking up on and internalizing social cues because we're social animals. We learn what works and what doesn't in many different situations when we laugh and it becomes a part of how we express ourselves.",
"My laugh changed once I started doing breathing exercises and laughter yoga. I went from an automatic \"heheheh\" to a more deeper \"Hohahaha\". Now everyone compliments me on my jolly laugh... which makes me self conscious about it.",
"I think that it's something that bonds people, like a tribe thing. Your laughs will get closer to match each other the more you spend good time with them or someone."
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7ckro0 | Why is an average global temperature rise of a mere 1.3°C over the course of 50 years environmentally impactful? | Other | explainlikeimfive | {
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"How much energy does it take to heat a cubic meter of air by 1.3°C? Now, how much energy is that in total, when you spread out that 1.3° of average surface warming across the entire surface of the Earth? If expressed in terms of detonations of 15KT equivalent TNT nuclear bombs, it would be like the energy released at Hiroshima multiplied by more than [2,549,000,000 times]( URL_1 ) at the time of this writing (Based on heat accumulation data and calculations [here]( URL_8 )). It would be astounding if that much energy was released and there were no meaningful environmental impact whatever. So what impacts have we seen so far? 1. Hundreds of billions of tons of ice has been lost to the sea from glaciers and the polar ice caps. 2. The average sea level has risen 20cm over the past century. 3. Arctic sea ice has declined by millions of square kilometers over the past half a century. 4. Plants and animals have migrated upwards in altitude and polewards in latitude. 5. Wildfires and droughts have increased in duration and intensity. 6. Extreme precipitation events have increased in duration and intensity. 7. The structure of the atmosphere is changing: the tropopause is rising, and the stratosphere is cooling. 8. This is a side effect of carbon dioxide emissions rather than warming per se, but the oceans are becoming more acidic. Now at this time, there is some cause for concern in some places. Nothing that is particularly threatening to global civilization, and perhaps not even that much harm has occurred to life on Earth specifically because of climate change. However, fossil fuel emissions are like the steering controls of a supertanker or a cruise ship. The final result of the last emission is carried forth by tremendous inertia. So whatever carbon dioxide has already been emitted, will stay in the atmosphere for [tens of thousands of years]( URL_2 ). Of course, fossil fuel emissions will not magically stop today or tomorrow. We are already committed to at least 1.5°C of warming, but realistically we may be looking at 3-4.5°C of warming by the end of the century. The world doesn't end in 2100, of course, so the maximum warming will certainly be higher than that in the 22nd century. Sea level rise will continue for [thousands of years]( URL_4 ) and dramatically change the coastlines of the Earth. 4.5°C of warming, to put it in perspective, is the [same magnitude]( URL_0 ) of change as the depths of the last ice age, when Boston was under a mile of ice. Such a world is almost unimaginable, as we have no geologic analogue for any prehistoric time when the Earth warmed that fast. Values beyond 4.5°C cannot be discounted. If things get very bad, parts of the Earth may be [rendered uninhabitable]( URL_3 ) for humans who stand outside of air-conditioned buildings for too long. For more information, a [new report]( URL_5 ) has just been released by the American government that summarizes the scientific community's latest understanding of the environmental impacts of climate change and related issues. Naturally, you should also consult the [IPCC]( URL_6 ) for the gold standard in climate science and policy analysis, if you have *a lot* of spare time. For a comprehensive list of rebuttals to various climate change myths that are circulating in the media and on the internet, [this]( URL_7 ) is a great resource.",
"Among other things, warmer air holds more moisture, making storms effectively worse. With each degree Celsius increase in sea surface temperature, the atmosphere holds 4% more moisture, which can make for worse hurricanes and typhoons. Warm temperatures mean glaciers melt faster, and so do the polar ice caps. Glaciers are a main source of river water.. we need rivers.. Melting ice caps means higher sea levels and this is also a disaster for animals that need ice covered areas, such as polar bears in the north.. and penguins in the south have a harder time finding food thanks to the warming. It goes on and on really",
"It isn't a \"mere\" 1.3 degrees. Global average temperatures changing by 1.3 degrees in under 50 years is an unprecedented rate of change, rivaled only by climate changes resulting from catastrophic events like extreme volcanism or meteor impacts or other mass extinction events.",
"This is enough to melt a fair bit of ice, causing sea levels to rise perhaps a meter or so -- more in the most affected areas. Also, the temperature rise won't be even -- some places may not warm at all, while others may warm by several degrees. This will affect the prevailing winds and drastically alter the climate in some locations.",
"Let's play a game. For 180 days starting March 1st, you give me $100. Then for 180 starting September 1st, I give you $100. Overall, we break even, right? Now let's change the game by a \"mere\" $1. In the summer, you give me $101, and in the winter I give you $99. Now I am making $360 a year off of you. Still think that $1 is insignificant? That's how a global temperature increase works. It not about a barely perceptible change, it is about heating more and cooling less, day after day, shifting the equilibrium. That means glaciers melting more, lakes evaporating more, crop-eating insects active longer, until the reach a new equilibrium, one we might not like."
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"http://www.pnas.org/content/107/21/9552.abstract",
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7ckxr9 | Why does Molasses spoil while Honey doesn't? | By my understanding, Honey is so concentrated in sugar content that it sucks water out of the bacteria. Wouldn't Mollasses do the same? | Chemistry | explainlikeimfive | {
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"It's a threshold issue: A fluid compound need 20% water to support bacterial growth. Molasses is about 25% water whereas honey is about 17-18% water. That's is why Molasses will 'go bad' but honey will not.",
"Sure, but honey has more sugar than molasses does, as a result the effect is worse for the bacteria in honey than molasses and more can survive in molasses."
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7cm02r | How does supernova have shockwave that can travel through space and trigger star formation? | AFAIK, the space is vaccuum, or near-vacuum in some parts, so I'm wondering why can a supernova have shockwave (as stated in a book I read in library, I forgot the book's name) that can also trigger star formation. I know shockwave is a concussion that can only travel through a medium. | Physics | explainlikeimfive | {
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"That shockwave is radiation and matter(particles) that are accelerated outwards at closed to the speed of light and doesn't require any medium to travel.",
"Deep space isn't empty, there's still around 10,000 hydrogen atoms per cubic metre. The shockwave passes through this very sparse \"gas\". Space also has [true voids]( URL_0 ) but they are uncommon.",
"In this case you seem to be ruling out space-time itself as a medium. So the shockwave is comprised of all kinds of shit (think a really really really fucking huge nuclear bomb), but some of that shit is elements from the star that exploded. These elements can form giant gas clouds called nebulae. Over time some of this gas might collect around a more massive area of gas (basically creates a gas planet like Jupiter) and keep on collecting more and more gas until it's so massive and dense that a sustained fission reaction begins and that's pretty much it as far as we know. edit: spiced it up with a few sentence enhancers.",
"You are right the space is in fact (mostly) vacuum and completely empty. The thing is stars are full of matter, ranging from Hydrogen, the smallest atoms to Iron which is the heaviest atoms formed in stars. Now, when the star goes supernova, it is because the pressure is so high it explodes. that is how the matter in the stars is thrown out into the empty space. So basically the shock-wave consists of these materials (more matter is formed during the supernova and that is how we have heavier elements in the universe like gold). This material is the one responsible for some nebulae you can see in space and planets formation. Hope that helps",
"Stars travel around the core of their galaxy, and sometimes they reach the end of their life (or fuel) when they are near a gas cloud. If a star goes supernova, it emits enormous amounts of matter, basically most of the stuff around the reactive core. The matter is blown out into space at enormous speeds. Now imagine a huge gas cloud, all those gas molecules resting there, evenly distributed (simplification). So, a few thousand years after the star exploded, the matter wave hits the cloud, and the molecules of the gas cloud get pushed together a bit. Next, you need to know that every bit of matter has mass, even those tiny molecules. And more matter means that there is more mass. And what comes along with mass? Right! Gravity! Little mass has little gravity, more mass has more gravity. Lets get back to our gas cloud. It got compressed a bit, so now there is more mass and more gravity compared to other parts of the cloud. This imbalance is enough for the surrounding gas molicules to be pulled closer by the force of gravity, leading to even more imbalance. This takes a while to happen but ultimately its leading to a huge ball of gas, with ever more gas being pulled in. It gets huge enough so that in its inner core there is such a high pressure and temperature that fusion reaction is setting in. A new star is born!"
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7cm9ks | had had usage and the logical deconstruction of the following punchline | A teacher wants his two students, James and John, to describe a man who, in the past, had suffered with a cold. James said, "the man had a cold," which the teacher said was incorrect. John said, "the man had had a cold," which the teacher was pleased with. So in conclusion, while James had had had had had had had had had had had a much better effect on the teacher. | Other | explainlikeimfive | {
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"That's a wrong punchline I assume. This makes sense. John, while James had had “had”, had had “had had”; “had had” had had the teacher’s approval."
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7cmfhj | Why do ADHD meds like Vyvanse have a tendency to cause headaches? | Biology | explainlikeimfive | {
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"Medical student here. Headaches are finnicky because they can have many causes, and it's hard for us to pin down the exact cause of any single headache. Could be low blood sugar, could be dehydration, could be tension/stress, could be a brain tumor. It's all over the place. With stimulants like Vyvanse, there's a few possible variables at play. The most likely -- and the one that affects people most often -- is dehydration. You can get headaches from being dehydrated, and stimulants like Vyvanse will dry you up in a hurry if you're not drinking more water than normal. Stimulants also increase your metabolism while lowering your appetite, potentially dropping your blood sugar to the point that you have a headache or migraine. These medications also cause your blood vessels to constrict, which can also cause headaches when it happens in your face/head. This is less common in patients who have taken a stimulant safely for quite a while, as your body doesn't experience these effects less strongly than a first-time user. If you are experiencing headaches from Vyvanse or Adderall, my advice in order of \"most likely fix\" would be: drink more water, eat more food, give it a few weeks of regular dosing."
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7cnigq | why does the skin used on grafts for burns look different to normal skin and will technology be able to improve this? | Biology | explainlikeimfive | {
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"Usually the skin used for skin grafts has been meshed---cut into a sort of honeycomb pattern using a machine. This allows a smaller skin graft to cover a large area of skin, and curve to fit the shape of the body. The problem is, that the lines of the mesh will show up in the healed skin. There are two ways around this. One is not to do the meshing. The problem with this, is that more skin is needed for the graft, leading to more scaring and pain at the donor site. The other is to use a different type of graft: new technology is allowing skin to be \"grown\" in the lab, using the patient's skin cells. This takes more time, as the cells need to be taken to a lab and grown up, so it's not helpful for emergency surgeries, but is used in other cases.",
"even full grafts do not look the same as the rest of your skin it just doesn't have the fish net pattern. I'm not sure if they will ever be able to perform a flawless graft. The scar site is active for atleast a year after surgery, pressure garmets are used to help with scarring, but since the human body is always moving, growing, and not perfectly flat it's hard to get a consistent pressure on the area. my daughter burnt her arm/hand when she was just under 2 years old. It sucks.",
"Surgeon here. There are different forms of skin grafts, but the two most common are split thickness and full thickness. Split thickness is often meshed to allow it to cover more area (and typically takes better) whereas full thickness typically look better. The reason that skin is meshed is that you only take a portion of the dermal layer and the donor area will heal on its own. On a full thickness graft, the original donor has to be sutured shut. Meshed grafts look worse. One thing to keep in mind is that a scar takes about 18 months to fully form. It softens and the color matches better with time.",
"Aside from meshing the skin for expansion, all the various cell types may not survive the transplantation. This can cause differences in pigmentation and is due to the thickness of the graft, the amount of dermis left in the wound bed, and the composition and allignment of the extracellular matrix between the graft and wound site. Source: Am PhD in burn injury research.",
"Let’s also remember that due to the nature of deep burn injuries that the underlying fat layers underneath the skin are also damaged and often removed in the debridement. Any grafting of these fascial deep debridements will not look normal in any way shape or form due to missing that fatty layer.",
"Skin gun is a new way to treat burn patients. It's not obtrusive and grows new skin back much better than grafts. Look it up. It's pretty cool. I'm no expert so I don't know how it works for very bad severe 3rd degree burns. Is there a doctor that had experience with this that can answer?",
"2 reasons: consistency and scar tissue Skin grafts are put into a machine that turns it into a mesh. This allows large areas to be covered, and allows them to scape less skin off of a donor area. The problem is that this new skin is mostly a mixture of very basic skin structures, and the regrowth in turn, is also very basic. Natural skin is wavy and blotchy and overall a complicated organ, so when you replace it with a basic and uniform material, it will only grow basic and uniform, and the replacement areas will grow into a scar tissue, which also only grows in one direction (uniform shape, color, and consistency), and lacks the elastic properties of the original skin.",
"Wound Contraction.. Without a full thickness graft the burn area will undergo a process of contracture to fuse the wound site to prevent infection. This leads to more scarring.. A full thickness graft without meshing is difficult for large burns without meshing",
"Because the grafts aren't able to regain as much functionality as healthy skin. Right now research is trying to recover the ability to grow hair, grow sweat glands, and sense of touch, but its really diffiulcult to do so while being biocompatible. The main purpose of these grafts are to regrow the outer skin layer, but they don't do much else.",
"I recently saw this kind of stem cell spray which is used to treat burnso. Apparently the stem cells are harvested from the patient and then sprayed onto the burn area. The skin then grows back and looks amazing in comparison to conventional treatment. I did see this on reddit though, so you know... Pinch of salt and all that.... Edit: URL_0"
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7cnrc3 | The difference between the Thor: Ragnarok light technology and conventional slow-mo technology | Technology | explainlikeimfive | {
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"[Watch this]( URL_0 ) Several things are happening to achieve the look from Thor Ragnarok. 1) The camera is shooting at an extremely high FPS. Thus giving you slow motion. 2) The lights and the camera are also moving extremely fast. 3) The result is a visual effect that makes the slow motion footage look slow AND normal speed at the same time. The subject is slow but the camera motion and light movement is fast.",
"Conventional slo-mo takes many frames per second and plays them back at normal speed. This makes things see to move more slowly. Strobe-tach, and related technology, are very different. If you have multiple flashes per frame, you get multiple images, but regardless you get no motion blur because the light is only on for a tiny bit of time. If you shoot a moving thing at 24 FPS, traditional movie speed, you get motion blur of approximately 1/24^th of a second. If you shoot that same motion at 240 FPS and play it back at normal speed everything is slowed down and you get 1/240^th of a second motion blur. If you shoot the same motion at 24 FPS under a 240 Hz strobe, you get 10 unblurred images per frame and no slow down. If you shoot at 240 FPS under a 1200Hz strobe you get five clear images per frame and those five overlapped images move slowly. It looks a lot different because your eye integrates the multiple images differently than it handles motion blue.",
"The way I understand it, the lighting, in this rig, moves very quickly across the subject so that when you slow down the action, the light looks like it's moving normal speed (giving you the impression you're viewing the scene in real time) but the actors are moving in super slow-motion. The effect gives it a surreal, dreamlike quality.",
"The title is a bit misleading I think. If I understand this correctly it's conventional slow-mo from the cameras perspective except that you add an array of appropriately synchronized strobes. This way you can \"move\" the light source by a significant amount even during super fast slow-mo since you don't actually try to move a physical light source at absurd speeds but you fire strobes along the path in sequence. Similar things were done for cameras in the matrix movies IIRC. Essentially they set up a ton of photo cameras along a camera path and then triggered them all at the same time. That way you can move along the path of the setup cameras while the action remains frozen."
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7cnv5d | Why do we no longer have to dial a one or zero before placing a long distance call? | Other | explainlikeimfive | {
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"Assuming you mean in North America. The URL_0 The +1 was a way to accept toll charges, most phone plans now include no long distance charges. so the 1 is no longer required. * 10-digit dialing: NPA NXX xxxx * 11-digit dialing: 1 NPA NXX xxxx (1 is the NANP trunk prefix for long distance circuits) Since most phone companies now include national long distance. the 1 is no longer needed. The reason that almost everyone has to dial the area code even for local calls is because of the overlay of area codes over existing areas. source: Wikipedia, and I work for a phone provider",
"Old phone systems would listen to numbers as they were dialed, so when you pressed the first key, it registered that number, then when you pressed the second key, it registered that number, and so on. The \"1\" indicated that you were entering a ten digit number with an area code. Otherwise after the seventh key, the phone system would not know if you were going to enter three more digits, or if it should connect the call. That's also why you had to enter \"9\" on business phone systems, so that it'd know if you were dialing outside and should expect a 7-10 digit number, or dialing an extension and should expect a 3-4 digit number. Modern phone systems are way more intelligent, making the \"1\" no longer necessary. Particularly for cell phones, since they send the number all at once, so the phone system can just look at the whole number instead of reading it digit-by-digit."
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7cnwg6 | How do muscles grow by lifting heavy weights | Other | explainlikeimfive | {
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"Imagine all the parts of your body are like different departments in an office, and they're constantly sending each other messages to make sure the business runs smoothly. If you don't make sure each of the departments are properly stocked up with supplies, your business comes to a screeching halt and you are in trouble. When you work out, it's like all of a sudden one department has a bunch of extra work because you got a big business client. So they start sending out messages to all the other departments, 'hey we need more gas to make all these deliveries'. For a little while, they have to make it work just having some people work over time, but they end up tired and grumpy with all the extra work they have to do. But they think this big client will stay with the business, so the department with the extra work says 'hey, we need more people to keep up with all this work'. So they get to hire more people, and the department gets bigger, but they have more costs associated with just day to day stuff since the department is bigger. So when they don't get any work from that client for a while, they have to fire some people and downsize.",
"The muscle rips/tears slightly when strained. It repairs the rip by growing over it. Repeat. Repeat. Repeat. If your diet is right as well you will lose the fat around the muscle too which allows more definition to be seen under the skin.",
"To be a little more specific, there's 2 types of muscle growth. One involves the muscle cells themselves growing actually growing (myofibril hypertrophy). This is brought about by lifting very heavy weights. It causes the muscle to increase the size of the tiny little fibers inside the cells that are what make the muscle move. This actually has somewhat of an upper limit and outside of taking steroids it won't really cause as much visible muscle growth, mostly strength growth. The other type is when the energy supply your muscles need gets an increase in how much they can and do store (sarcoplasmic hypertrophy). This is mostly brought about by draining the muscles supply of energy with less weight but more repetitions. This will actually lead to more physical size increase, but doesn't necessarily mean more absolute strength. On a funny note, it's entirely possible for a person to not look very big and muscular to actually be much stronger than your average body builder. Size of muscle doesn't strictly translate to how strong you are."
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7cnykg | In cartoons, certain clothing patterns such as checkered or plaid, it seems like it's a static pattern that the characters move around on. Why is this, and how is it done? | Other | explainlikeimfive | {
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"On a technical level, their shirt is actually transparent, and there is a layer with the picture of the pattern behind the layer the character is drawn on. The character and their shirt moves, but the background layer does not, resulting in what you've described. The reason for doing this is that its a cheaper/faster/easier way to animate clothing with those types of patterns. The alternative is redrawing the whole thing each time the character moves slightly.",
"In whatever animation software they use, the shirt layer is transparent and above a motionless layer of plaid underneath it. It's done because it's cheap, lazy and easy compared to actually animating a plaid textured shirt."
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7cnz8b | Why can't we outrun bears? | Biology | explainlikeimfive | {
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"Because they are good runners. I’m sorry they don’t seem that way, but bears, and many other animals are considerably faster than humans. We cannot outrun them because they are faster than we are. Nothing magical about it",
"Bears are huge and most of that is muscle. Depending on species they are capable of reaching speeds of up to 30 mph. Now, like most animals, these high speeds are sprints. What separates humans from most animals is our ability to maintain high speeds for long periods of time."
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7co6e0 | How are IP addresses allocated when using mobile data such as 3G/4G? | Technology | explainlikeimfive | {
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"Same way, it's still a network of routers and switches. Think of the cell towers and 4g antennae as the wireless access point. Your pc and cell phone access the same isp infrastructure after a certain point.",
"Still DHCP servers as with any other ISP. The cellular nature of the network doesn't change the principles involved. Note that the backbone networks in telecom companies aren't always the same as the routed IP networks in companies. Things are changing, but many still use a different, connection-based packet switching technology called ATM. ELI5 version: in this setup, each cellphone tower isn't a router or DHCP server itself, but instead \"tunnels\" all its traffic straight to a more central location to be separated and handled appropriately. Addresses are allocated at that point. Switching between towers doesn't trigger a new DHCP address process every time."
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7cobrx | Why does the Salt in McDonald's Salt Packets Taste Different from the Salt They're Prepared with? | Chemistry | explainlikeimfive | {
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"It's all just salt. The difference is the size of the grains. The salt that is used when making french fries has super-fine crystals - it's almost a powder while the salt in the packets is more like a traditional table salt. The size of the salt crystals greatly influences how it impacts your taste buds."
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7coh9m | How do dancers not get dizzy when they spin around super fast? | Biology | explainlikeimfive | {
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"It’s called spotting. It’s a technique where you spin your head faster than your body and focus on one spot throughout the rest of the turn. [video example]( URL_0 )",
"We call it turning, not spinning. Usually the turns you see are pirouettes, where the dancer is on the toes of one foot and the other leg is bent at the knee. We set up by bending our knees (while both feet are still flat on the ground), get some momentum going by starting to move our arms in the direction we’ll be turning, keep our eyes locked on one spot slightly above eye level in front of us, and push off one leg to the toes of the other. Focusing on one spot with our eyes keeps us balanced straight up and down, allows us to do multiple turns without stopping, and keeps us from getting dizzy. We have to turn our body while keeping our head in place for as long as possible until it absolutely must turn, and then immediately focus on the same spot again."
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7col58 | Why does the human eye see more shades of green than any other color? | Physics | explainlikeimfive | {
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"The natural world is mostly green so it is better differentiate green colors from each other compared to other colors",
"> Why does the human eye see more shades of green than any other color? Differentiation between subtle shades of green can aid in identifying plants as well as seeing things within and around green plants. That leopard hiding in the leaves might be given away by subtle differences in shades of green, while there is less importance in being able to pick apart shades of yellow.",
"From a proximal (non-evolutionary) biological standpoint, the answer would be that green/yellow is the part of the frequency spectrum in which we have the best frequency resolution. Look at [this graph]( URL_0 ). You will notice that there are multiple different photoreceptor types that have some degree of sensitivity overlapping in the 'green' area. Compare that to the wavelengths under 400nm: There, we have essentially only ONE photoreceptor picking up those wavelengths, and this is why it is very hard to tell these colors apart / we can't perceive many different hues. Good color perception (ability to tell different shades apart) is a result of having multiple different photoreceptors with somewhat overlapping sensitivity ranges."
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7cop0f | What is actually happening when a car is done "warming up"? | I mean besides the literal "the engine is now warm." After I've started my vehicle, I notice the RPMs slowly dial back. Say, from 1200 to 900, over the course of about 3-5 minutes. What is actually occurring that causes the RPMs to start at a higher value, then go to a lower one while the car idles? | Technology | explainlikeimfive | {
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"In a modern car it's down to the engine computer making the engine run at a higher idle to increase the speed things warm up at. One of the big ones is the catalyst in the catalytic converter. This is basically a bunch of exotic elements in the catalytic converter that need to be warm before they properly do their job of reducing the emissions from the engine. As well as that when the engine is stone cold, fuel doesn't want to vaporise as easily, and it's the vapour that burns, not the liquid. So basically to get up to efficient running the engine has to be warm, so the computer makes it rev a little to get it there faster. Other points are getting oil warmed up so it flows properly around the engine. All in all there are several pretty good reasons for the engine warming up, but in a modern car, it's literally the computer monitoring temperatures, and making the engine rev a little bit more till those temperatures are reached.",
"I would add that there is no need to warm up modern engines. Most processes are controlled by a computer. You just supposed to start moving without high load first 5-10 minutes."
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7copag | How is mains AC turned into usable DC power, particularly in the context of a desktop computer PSU? | Technology | explainlikeimfive | {
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"AC is converted to DC using a rectifier. Diodes (which restrict current flow in one direction) are used in a bridge circuit so that each half of the AC waveform is output at the same polarity, and then capacitors are used to eliminate the ripple and smooth the DC output. To drop voltage, a transformer may be used on the input AC, or a DC-DC converter (inverter / rectifier) may be used on the output side.",
"Here's a [circuit diagram of a rectifier]( URL_0 ). On the left is where the AC is coming in (assuming it's already been stepped down from mains voltage). AC current reverses direction several times a second: as a waveform, it has the appearance of a sine wave. Then we come to the actual bridge rectifier, consisting of four diodes, represented by the arrowheads, labelled D1 to D4. A diode will only let current pass in one direction, as signified by the arrowhead. Imagine the AC current flowing into the circuit\\* along the wire to the junction between D1 and D4 (the connection at the top of the bridge). It can't flow through D4, because it's pointing the wrong way, so it flows instead through D1. This takes it to the + terminal, where it meets D3, which it can't flow through. Its only exit is to follow the arrows around the circuit (\"load\" means \"whatever thing you're providing power to\") and back to the - terminal. There it flows through D2 and back to finally complete the circuit. When the AC current reverses direction, it enters the bridge at the bottom. From here, it can only flow through D3 to the + terminal, where it follows the arrows around the circuit and back to the - terminal: there it flows through D4 and out. So whichever way the AC current is flowing, it can only flow through the DC part in one direction. The resulting waveform is seen below: it's the pink line. Now, instead of reversing direction several times a second, the current flows in one direction, but in pulses. This is where the capacitor, marked C on the circuit diagram, comes into play. A capacitor is an interesting component: it charges up with electricity, and then releases that electricity again. So when a pulse of current comes, some of it is diverted to the capacitor and charges it up; when the pulse has passed, the capacitor discharges and dumps the electricity it has collected back into the circuit. This smooths out the pulses: it's not perfect (there's still a ripple), but usually good enough. -------- \\* Note: I'm talking about the current here, which flows from positive to negative. However, the actual electrons themselves are negatively charged, so they flow in the opposite direction. I'm talking about the *current*, not the electrons. The reason for this is that the positive and negative poles were so named before the nature of electrons was understood: at the time, scientists had a 50/50 chance of getting it right, and they picked the wrong option.",
"It's a combination of a half- or full-wave [rectifier]( URL_0 ) with a capacitor at the output to flatten and stabilize the voltage. At the core, it's really just one or more diodes which only lets current flow one way, thereby turning off or inverting the negative side of the waveform which moves the average positive (and thus the DC equivalent voltage)."
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7cotmo | What makes your spit all thick and gloppy? | Biology | explainlikeimfive | {
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"text": [
"Physiologist here. Your saliva contains mucins. Mucins are proteins that are attached to long branched chains of sugar molecules. Mucins play an important role in defending against bacterial infection, particularly against pathogenic (harmful) bacteria. When you dissolve long-branched chains into water, you make the water more viscous (thick). The long branches of sugar molecules attached to salivary mucin proteins make your saliva thicker than pure water - they also bind to harmful bacteria, clump them together, and help your immune system to destroy them.",
"dehydration would be one reason coughing up mucus from your lungs/pipes would be another reason"
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7cox7v | why is EA games facing so much backlash from Redditors? | Technology | explainlikeimfive | {
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"text": [
"Most recently it is because of their release of Star Wars Battlefront 2. It takes 40 hours of playing to unlock darth vader, or you could just buy him... Microtransactions have always faced a lot of criticism, as well as dlc that should have been included in the main game. Basically EA always rushes their games, released the unfinished bits as dlc, and charges microtransactions (not to mention their insistance on using EA origin). They are just a bit to blatantly cash grabby as a company. Which is a shame considering their roots. Here is their recent comment that got 371k downvotes: URL_0",
"Basically EA is like the video game equivalent of Comcast in terms of greedy, malevolent business decisions and contempt for consumers. One of their most hated practices is buying respected studios, running them into the ground, and closing them l when there's nothing left but a empty shell with a tarnished name. The latest act to draw ire however is the upcoming title *Star Wars Battlefront II* giving those who buy in-game items with real money a competitive advantage in a game that already costs $60 at the very least."
],
"score": [
18,
5
],
"text_urls": [
[
"https://www.reddit.com/r/StarWarsBattlefront/comments/7cff0b/seriously_i_paid_80_to_have_vader_locked/dppum98/?st=j9y91vfu&sh=16f42e2a"
],
[]
]
} | [
"url"
] | [
"url"
] |
|
7coxo6 | How would charging a charger work? | If I were to take a 5000mah battery pack (like the ones used to charge cell phones) and use it to charge another 5000mah battery pack, could i do so indefinitely, or would there be a constant loss in the transfer? | Technology | explainlikeimfive | {
"a_id": [
"dprhsop",
"dprhp37"
],
"text": [
"There would be losses. As the pack charges up, it also heats up. That heat eventually dissipates out into the air around it and is essentially lost. That heat comes from the energy stored in the other pack so if you constantly charged one pack with the other and then swapped and charged the other pack, eventually all the energy would be converted to heat and then lost.",
"Both parts of the cycle (converting cell voltage to USB voltage, and vice versa) have an efficiency far less than 100%, not including minor loses such as resistance in the cables/connectors/cells/etc. If such a cycle were let to run, both batteries would eventually end up discharged."
],
"score": [
10,
3
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
7cp33o | Why does putting salt on ice cause it to melt? I understand that salt water has a lower freezing point, but doesn't the salt have to dissolve into liquid water for that to ocurr? | Chemistry | explainlikeimfive | {
"a_id": [
"dpriubj"
],
"text": [
"it does, and it does. there is always a little bit of water on the surface of ice. that water now mixes with salt and does not refreeze, and then interacts with the ice under it, little by little. It is far more effective when you put the salt out before the ice though, so it can create a nice salt water base to absorb the flakes as they fall."
],
"score": [
4
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
7cp4yo | How do our bodies know how to grow while in utero? | I understand DNA is the building block, but how do the original cells know how to divide in to, say, finger bones, or a stomach; and in the correct order? | Biology | explainlikeimfive | {
"a_id": [
"dprkkw8"
],
"text": [
"Scientists don’t understand all parts of the process fully, but basically, after a sperm fertilises an egg, that one big cell is set up to have a front and back, and a top and bottom - an axis. So imagine a line going from your head to your butt and your chest to your back. The instructions within your DNA then create gradients of different proteins along the axes - it’s really complicated with lots of genes and proteins involved. I kind of think of it as an orchestra and instruments come into play at different times according to how the piece develops. The genes involved are called homeobox, which is a bit like a stamp within the gene that indicates its group - like the Nike tick indicates sports clothing. These homeobox, or hox genes, set up the body plan because they are instructions that make proteins called transcription factors. Transcription factors in turn are proteins that control which genes are activated. They do this because they recognise specific sections of genes to either allow or stop them from activating. Biologists sometimes also call them master regulators, which does have a bit of a dominatrix sound to it outside of a group of biologists. So, a hox gene that directs development of the head will activate genes that begin to make head regions, like a sheet of brain cells that curls into a tube shape to make the beginnings of the brain. Once this basic structure is made, it grows and gets refined throughout development of the embryo. Source: I am a developmental biology PhD"
],
"score": [
9
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
7cp7p0 | why are so many historical East Asian figures like Sun Tzu or Ghengis Khan portrayed in paintings as fat or slightly chubby | Other | explainlikeimfive | {
"a_id": [
"dprk2g6"
],
"text": [
"Because many wars were literally about food, securing food, transporting food, and a person with any amount of chub had to be particularly wealthy/prosperous."
],
"score": [
10
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
7cp9hl | They say people who wash their hands alot and use alot of hand sanitizer are always getting sick because they dont let their immune systems build up. But if their always getting sick then in theory wouldnt they have the strongest immune systems ? | Biology | explainlikeimfive | {
"a_id": [
"dprle6s",
"dpry734",
"dprobw7"
],
"text": [
"I think its just a saying, I don't think data would actually show that people who have better hand hygiene are always getting sick.",
"This is the \"Hygiene Hypothesis\". Completely unproven, but based on the idea people are getting sicker more often in western societies. People do not get sick more in western societies, but when diphtheria is not a risk, you notice the common cold more.",
"In theory, the reason is that the average person who gets more exposure encounters little things that your immune system easily defeats without you experiencing any symptoms- this keeps it active and strengthens it so that when something slightly more nasty comes along your body can handle that too without you getting symptoms. Assuming the above is true, then by using something that kills off those very weak germs, your body doesn't have the practice to instantly defeat the slightly nastier germs, so you actually get sick and show symptoms when exposed to something that another person would have never even noticed. Alternatively, it's also possible that the natural flora on your skin (that is to say, benign bacteria that lives on everyone's skin, and won't get you sick under normal circumstances) blocks other bacteria from getting a foothold on your hands, because they are taking up all the resources available on your skin, or even actively combat the intruding germs."
],
"score": [
11,
3,
3
],
"text_urls": [
[],
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
7cpbtz | How are people able to fast for long periods at a time yet stay healthy? | How are people able to fast for long periods at a time yet stay healthy? I saw something about a man fasting 365 days. How that possible if the body needs Food to survive? | Biology | explainlikeimfive | {
"a_id": [
"dprlewp",
"dprsh23"
],
"text": [
"Fasting can be a pretty flexible term, especially when used in a religious context. The people who “fast for 365 days” are eliminating a specific thing, like red meat or bread, for a specific duration, and many of them rotate that “thing” every week or month. So they say they’re fasting, but really they are going without bread for one month, then without soda for a month, then without red meat for a month, etc. This demonstrates personal determination and commitment, but it’s hardly going without food altogether.",
"As /u/loveandsubmit points out, \"fasting\" can be very ambiguous when presented without qualifiers. What he describes is one possibility. Another case might be when one is very obese. There is an amount of body fat that is maintained when a person is at a normal weight, but excess body fat is stored when a person overeats. So if one eats much more than they need to live, they can store a significant amount of calories/energy in the form of fat. When fasting, the body switches over to use stored fat for energy, since none is available from food. Our bodies need food for energy, but also for protein and vitamins/minerals that are necessary for maintaining body systems and rebuilding damaged tissues. So those things would be the concern for an overweight person fasting for an extended period. There was a case of a man who fasted for over a year, while monitored by doctors, in which he consumed vitamin and mineral supplements, and I think a yeast supplement? He started out over 450 pounds and lost something like 270. So his calorie needs were provided by using up body fat, and his doctors provided supplements for other necessary nutrients, particularly when they found him deficient. Normally, a person cannot go for long periods without food like that."
],
"score": [
12,
4
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
7cpdzt | why do our muscles get sore when we get sick? | Biology | explainlikeimfive | {
"a_id": [
"dprt944"
],
"text": [
"When your body senses that something has gone wrong, say for example, that you fell down and cut yourself, it sends blood rushing towards the injured spot hoping to repair it. This is because in your blood, you have small units called white blood cells (WBC), which you have undoubtedly heard of before Now, the white blood cells get to the site of injury and they have multiple functions: getting rid of bacteria and helping to deal the wound One of the ways that WBCs work is by secreting a family of molecules called cytokines, which help send signals through the body to stimulate inflammation, pain, and recruitment of the repair systems in your body, since these are all defense mechanisms intrinsically programmed into you. Now, you're sick and feel awful and sore. What happened was your body, in response to the virus/bacteria/spore or whatever made you sick, pumped up WBC levels to deal with the foreign invaders What did we already say that WBCs do though? They make cytokines, which stimulate your fever and can make you feel all achy everywhere."
],
"score": [
6
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
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