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7q2fw1 | Biology | How can certain animals such as frogs and flies freeze solid and survive, but most mammals suffer extreme tissue damage? | The main danger with freezing is that the ice crystals that form poke holes in the cell membranes. Without functional cell membranes there is nothing (or at least not enough) to keep your cell-stuff in place and the cell dies pretty quickly. This is also how all antibacterial _chemicals_ like soaps and alcohol work (NOT antibiotics). Antifreeze prevents the formation of these ice crystals, or at least keeps them limited in some way that they do less or no damage to the cell membranes. This is actually used in microbiological labs; if you want to freeze your cells or bacteria, you put them with a bit of some specific antifreeze component. Unfortunately for most cells and bacteria antifreeze is also very toxic. But, some animals have evolved components that act with a similar function as antifreeze. | 3 |
9njncy | Culture | With the push for equality across the board, wouldn't it make sense to do away with asking race on forms and allow for the best suited to be selected for positions and other such things, or is there a reason to keep it? | If a company keeps a record of the gender and race of their current and past employees, then it becomes much easier to see if there is any sort of bias (explicit or not) in their hiring practices. If you don't track this information, then demonstrating that a company has discriminatory hiring practices becomes all the more harder. | 3 |
9nwhq1 | Culture | Why did we "suck" at drawing realistically until the Rennaissance? | It's complex and also involves a lot of what has survived over the years as well as ideas about the purpose and function of artwork. Take a look at the Fayum Mummy Portraits if you want good examples of realism way before the Renaissance. | 7 |
cmdg87 | Other | what factors make it difficult for police officers to be criminally charged even with body cams and more videos available? | it's not a procedural or legal or evidentiary difficulty. the difficulties are practical and political. the people who charge everyone with crimes are prosecutors and police. prosecutors and police have a very close working relationship as a result -- think in terms of an episode of law and order, where you've got the police gathering up the evidence and apprehending a suspect, and then they hand off to the lawyers to convict the suspect with the evidence. so, if you're a district attorney or some other kind of prosecutor, you have a very strong incentive, most of the time, to be very supportive of and to have a strong, trusting relationship with, the police. you have lots of important goals in common, and in terms of relationships with everyone outside of that bubble, you're on the same side. you both are anti-crime, you both probably have similar views on what laws should/shouldn't be passed, you both face the same pressures from the public in terms of being "tough on crime," being accused of being discriminatory or unfair or biased, getting in lots of trouble for when crime is bad or something goes wrong, etc. so when a cop is accused of a crime, that drives a wedge right into the middle of that relationship. suddenly you've got police against police, police against prosecutor, and you're not on the same side of the issue anymore. and that gets really awkward. the same incentives still exist to still be on the same side. it's still beneficial to everyone involved if the public believes you're all non-corrupt and non-criminal. it's bad for everyone if evidence comes to light that "the good guys" weren't so good, and it's also bad internally because, you know, the district attorney charges cop 3 with a crime, and cops 4, 5 and 6 who were good buddies with cop 3 look at the district attorney like, well, fuck you, you're supposed to have our backs, and now you've got an entire workforce with a problem, and now the cops don't have the DA's back, and that is probably going to result in the DA having a problem keeping their job in the longterm, politics being what they are, and also you'll have other political leaders who rely on being "tough on crime" who need the police on their side, so they have to weigh in to try to keep the support of police leadership by backing up the police and speaking up for the accused, and so on... it's just a very heightened version of the same internal politics that happen within a lot of organizations. and it leads to a lot of slaps on the wrist or "administrative leave" or anything that makes the problem somewhat go away without it becoming a massive internal fight. it's not like the evidence in these cases is lacking. there's just active incentive to not move forward with prosecutions. | 1 |
dt2eqb | Technology | How do players and computers read CD's and DVD's? I'm just wondering physically how is it possible? Why is it that if I wanna pick one song from the CD the player 'knows' where the song I want is? | The backside of the label is made of a reflective coating, so that when light is shone through the plastic of the disc it is reflected back out. A laser shines upwards through the disc. In the plastic of the disc there are microscopic dimples or *pits* that change how the laser light is reflected. Specifically, they cause the waves of light to overlap in a way that causes destructive interference, which means no light reaches the detector next to the laser emitter. So either there's a pit, or a land. Light enters the detector, or it doesn't. The 1s and 0s of binary are encoded in the pits and lands. It is *not* that a pit or land is a 1 and the other is 0. Instead, a 1 is when the laser detects a *change* from land to pit or vice versa. The laser follows tracks, like the grooves in a record. A chip precisely controls the position of the laser, so the player knows exactly where on the disc the reader is. That means it also knows precisely how fast the disc is turning. It uses that to calculate the clock rate, or how fast 1s and 0s should be happening. DVDs use a more precisely controlled reader and more sensitive reader so the pits can be smaller and closer together, which means more data can be packed onto the disc. The format of the data is also different. Blue ray players use a blue laser, which has a smaller wavelength. That means it can read smaller pits, so they can be even smaller than in DVDs and pack in more data. Blue ray players and HD-DVDs both have multiple layers, too. The laser has a lens to change the focus to ignore or pick up different layers. | 2 |
cvm9mb | Technology | Why do battery chargers (the type that charges AA and AAA battery's) require 2 battery's before actually charging them? | Because they're low quality. A high quality smart charger caters to each battery individually to give it the perfect charge, and maximize its life. The funny thing is, the highest quality charger on the market only adds about $6 to the cost of these AA Eneloop NiMH batteries: * [AmazonSmile: Panasonic K-KJ17MCA4BA Advanced Individual Cell Battery Charger Pack with 4 AA eneloop 2100 Cycle Rechargeable Batteries: PANASONIC: Electronics]( URL_2 ) * [HKJ Review of Charger Panasonic BQ-CC17 - URL_1 ]( URL_0 ) > A nice -dv/dt termination with only a small temperature increase and no trickle charge, this looks very good. [...] The charger is very good at filling the batteries. You need that charger to get the full life out of Eneloops. If you take care of them, Eneloops will last at least a decade, maybe longer. The charger also works with other NiMH batteries. If you don't have good NiMH batteries yet, get the ones I linked to above, and make sure your battery specifications match the packaging in this photo *(there are fakes out there): * [New battery day! 24 AA Eneloop NiMH batteries in 16 and 8 cell packs. : r/AAMasterRace]( URL_3 ) | 1 |
kiye40 | Technology | How the heck do school computers take forever to start up and my one is instant? | Schools have to buy lots of computers without much money, so they buy cheap computers. Cheap computers are slow. No one on Reddit can tell you anything specific about your particular computer without seeing it. | 5 |
lrjxdg | Biology | What exactly is happening with our eyes/brain when the room is spinning? Not due to alcohol, but if you have a head cold or vertigo & you turn too fast & you get the spinnies. Why do you see things spinning like that? | Your brain uses information from your balance system (in your ears) to figure out how you're moving your head, then uses that to "back out" the motion that causes in your vision so that you correctly perceive motion of outside objects. When you move your eyeballs everything on your retina moves, so your brain needs a way to figure out if that was motion due to \*you\* moving (not that interesting) or the object moving (very interesting). If you have a head cold or vertigo or spin, you temporarily screw up the motion sensors in your ears; they tell your brain that your head is moving when it's not (or vice versa). Your brain tries to reconcile this with your eyeballs and gets totally confused...your eyes say you're staying still, your ears say you're moving, your brain says, "F it, I'm out of here and going to split the difference." | 1 |
i2yp84 | Technology | how come scientists/developers cant make phones that capture and send odors,scents,smells? | Light is photons, you can make photos with quantum mechanics out of nothing using electrons shifting between atomic orbitals. Smells are chemical compounds, they are matter. We do not have a technology to make matter out of nothing. | 2 |
j0yo6f | Biology | How can social media platforms be bad for a person’s health? | They trick you to use them as much as possible, which is a kind of addiction. Also, prolonged device use can lead to insomnia (and who are we kidding, of course we're taking our phones to bed). Not to mention if you waste a lot of time on social media, you lose time which you could potentially use for exercise or other healthy habits. But that's just a potential that you lose. And if you hold your phone in a wrong way a lot you could probably get carpal tunnel syndrome ;) | 1 |
cdacvm | Economics | How much does it really matter where I buy my gas? Are “name brand” gas stations any different? | It used to matter. Gasoline is a formula of fraction products of petroleum. Before standards, some brands were famous for smelling different. Some charged more and were more expensive, or had a following. It hasn't really mattered since before widespread regulation on the quality of gas, maybe 70 years or so. | 8 |
6tjh66 | Technology | How do we take pictures of things in space millions of light years away from us? | We point a camera at it, and wait. Because the light from such distant objects is very dim the exposure time must be very long. The famous Hubble Deep Field picture took 342 separate exposures over 10 days. | 2 |
6e4n21 | Economics | Why does the price of name brand foods vary at different stores but the price of electronics such as video game consoles are the same at every store? | Most all our electronics are bound to a MAP (Manufacturer Agreed Pricing) contract. Apple is probably the strictest on MAP enforcement. Three strikes and we get our products yanked. | 6 |
dubbvj | Biology | Why do most animals follow the same facial structure/layout? Two eyes, a nose between them, a mouth with teeth under that, with ears on either side of the head. I know why they have those individual pieces, but all together they all seem to follow the same kind of layout. | ELI5 why most animals share the same features is because of the evolution tree: they have developed out of the same ancestor, like siblings look a lot like their parents, and thus like each other, but are A BIT different. Do this a lot more often and you have very different, but related faces. ELI5 why two eyes: the common ancestor had an advantage in hunting, feeding and moving when they have 3d vision and thus depth-perception compared to 2d vision and no depth perception. Thus all children and children's children got those features and this ancestor had a lot more successful children that survived and reproduced again. ELI5 two eyes and a nose in the same place: most likely because it evolved that it is most favorable if the nose and eyes are close together as the brain is there too. Signal travel shortest this way and also you only need one central brain instead of two. You know that the brain is essential and thus a weakness, so it always is better to have one instead of two weaknesses. ELI5 ears on either side of the head allows for direction-identification. As sound travels at a specific speed, it hits one ear before the other. The brain notices this and can thus locate things better. Moveable ears probably have evolved in order to THEN have more hearing accuracy when you have the location, in order to identify the origin of the sound (friend or foe) or in order to hear more clearly what happens and where it moves to (hunting). All in all: common ancestry is the reason for common features, and "survival of the fittest" is the reason why it is THOSE features and not others. Edit: I was confronted on the evolution of the eye and remembered I have seen an amazing video that clearly and understandably explains it better than words ever could and want to add it now (at 53 upvotes, sorry yall missed this): [ URL_0 ]( URL_0 ) u/In-Kii | 4 |
bh3pxr | Biology | About Natural Selection - how can useless features on creatures disappear, as they are useless, but not actually a disadvantage? For experience tails in human.. etc? Isn’t it Lamarck’s theory, which was proven wrong? | You don’t need to select against a useless trait for it to go away. Mutations are happening in your sex cells and being passed on to your offspring all the time. If it’s a bad mutation, the offspring will not survive or have decreased or no offspring and the bad mutation will not be passed on. If it’s a useful mutation, it will be passed on and increase in the population over time due to natural selection. If it’s a mutation that has neither benefit nor detriment, the n sometimes it will be passed on, sometimes not, but over time, such mutations will eventually increase in the population because they’re not actively being selected against. | 4 |
dmqcge | Economics | How does the $1 store stay in business with inflation, rising wages, etc.? Wouldn't their margins be getting thinner and thinner every year? | It would if their profits per sale were the same. Are there any dollar stores left that actually sell everything for $1, anyway? | 4 |
6vbahv | Engineering | why do bombs and missiles explode in the air above their target? Instead of hitting the ground/target and exploding? Edit: thanks for all your informative responses! I have a lot to read through | Exploding in the air means that the shrapnel hits a larger area and goes into trenches that a ground detonation would miss. The devices used to achieve this are called proximity fuzes. | 11 |
b9l1tq | Other | why pillows, blankets, etc have those tags that are "penalized by law" if removed by anyone but the consumer | It's similar to food labeling laws, you'd see similar penalties if you blanked out best before dates. Those tags have manufacture dates on them that are mandated by whatever authority the distributor is based in to be displayed. Bedding believe it or not has a sell by date like food, although the shelf life is obviously much longer. As for wether these laws are enforced anymore, you'd need to ask a lawyer. I don't think you'd see any fines, nor would it be economically advantageous to remove the tags. | 3 |
6m6sk3 | Physics | Why is time "relative"? | It's a complex notion, really hard to dumb URL_0 suggest to go and look PBS science on YouTube, it's really interesting. Anyhow. Imagine having a massless box (meaning a box without matter, impossible, but just imagine it). Inside there's a single photon, the light particle. Every second, it goes up and down. So every time it touches the bottom, a second passes. Now imagine that I'm standing in front of you, and I too have the same box. I'm on a train, and gonna move forward: the light particle has more distance to cover now, because it's not attached to the box. So my time actually slows down. But this is by your perspective. By my perspective my time is moving normal, and since to me you're the one who's moving, it's your particle that has more distance to cover. So to me, your time is slowing down. This doesn't mean that both times ate slowing down, it just depicts the relativity of it all. | 2 |
bcvggg | Biology | If too much salt is considered bad for you, how do people in countries like Japan and other Asian countries stay so healthy when their food is so high in sodium? | I'm Chinese and grew up in China/eating Chinese cuisine. Chinese/other East Asian food IS generally much lower in sodium than the Western/Canadian food I have now. The thing is, using your pickled plum example, we're not shoving forkfuls of this stuff down like pasta. Yes, lots of things are pickled and very very salty by themselves, but they're usually used as basic side dishes to accompany rice. I might eat 4-5 tiny pickles or like, half a salted duck egg per large bowl of plain rice or porridge. Overall, not that much sodium. | 21 |
cbwgro | Chemistry | How does henna work? It’s on your skin for less than half an hour, how does the color stay for weeks? | It's a dye and binds to proteins in the top layers of the skin, staying until the skin is shed. It's not particularly different than any other staining dye, and is left on long enough to pass deeper than just the top of the epidermis which is quickly shed so that is it more persistent. It is unlike a tattoo which pushes ink deeper than the epidermis into the dermis, which is not constantly shed. | 1 |
6cy93m | Other | How can there be so much opiate prescription drug abuse when, in theory, the number of manufactured pills and the number of prescriptions are known? Isn't it obvious the pills are being abused? It seems like it would be easy to see either the total number of pills made is roughly equal to the total number of pills prescribed. Of course there would be error, but the apparent market of the illicit opiate abuse seems to dwarf the actual intended purpose. | Very nearly all of the prescription opioids used in the US are almost certainly obtained with prescriptions and then used or sold. The issue is that those prescriptions are not necessary or obtained by patients faking pain (which is remarkably easy to do and difficult for someone else to prove you're doing it). | 55 |
8touhf | Physics | How does dust just “settle?” Title says it all but to add to it: I’m just finished lwatching an abandoned video and these two guys were looking in the home then they went out to look in the barn and found an old ass Mercedes but it was almost completely covered in dust. How is this possible especially with wind blowing (I realize not constantly and generally not hard enough) on any given day and the barn was old af and had open holes which would allow for the wind to blow some of it off? I realize this isn’t always the scenario bc the wind doesn’t blow *every* day (same with a home that isn’t well-ventilated) but it still baffles me how dust and dander can just cling to a surface and not move. | Dust settles because it is heavier than air is. Unless it is being constantly mixed up, by winds or air currents, it will end up falling slowly through the air until it lands on a surface. It then takes quite a strong wind to blow it off that surface. In your case, you have a drafty barn. But even in a gale, there won't be more than a gently draft in the barn - not enough to lift dust from the surface. When there is a gale, dust will be blown into the barn, and when that dies down to a normal breeze, there won't be much air movement in the barn, and it will settle. The gentle air movements in the barn won't be enough to lift dust from the surface, so it remains and builds up. | 3 |
gpbwgx | Technology | Why did so many computers use “control alt delete” to “unlock,” was there a reason? | Ctrl-Alt-Delete is a special set of keys that Windows doesn't pass through to programs on the other side which makes it a bit more secure and very unlikely to happen accidentally When you press keys on your keyboard they get handed to the motherboard which passes them off to the OS which then gives them to the focused program. Except Ctrl-Alt-Delete, when Windows sees that 3 key command come in it just snags it for itself and doesn't pass it along. This also protects you against programs that may create a fake windows Login screen as pressing Ctrl-Alt-Delete will bring up real Task Manager and hopefully make you realize that login screen isn't a real one. | 3 |
d0m7wp | Engineering | Why do major tunnels have buildings at the entrance? What is inside? Like this: URL_0 | They house all the equipment needed to operate the tunnels systems. Ventilation, monitoring systems, etc. They often have offices in them for the people that support the tunnel. It's much more complicated than just a hole in the mountain. | 1 |
hgu75m | Other | Why are majority of promotional offers not available in Alaska, Hawaii and Puerto Rico? | Because for most products, the nearest distribution hub can be thousand of miles away and products must be flown or shipped in at a much higher cost than sending by truck. So much higher that the cost to the offerer isn't worth the expected benefit of the promotion. | 2 |
8uqsjv | Biology | Why do spiders shake and vibrate when scared? | The leading theory seems to be that creatures with less acute eyesight than humans (a lot of them) will be unable to resolve the quickly moving spider as anything but an indistinct blur. Because of this it is unlikely they will be able to eat the spider. | 1 |
8y8ubz | Biology | why are we unaware of the passing of time while asleep? | So the answer to *why* our bodies do anything is often the same across ELI5 - natural selective pressures when we were still in the food chain. You are the product of a long and unbroken chain of *surviving* organisms, stretching back to before the distinction between plant and animal was even clear. So the question is *why have our bodies not been given a sense of how much time is passing when asleep*. The answer being **there was no selective pressure to make it so**. Nobody was getting removed from the gene pool for not having it. Nobody with it was getting mad-pussy from females because it was such an attractive thing to have. It only mattered that you were able to rouse *quickly* to an alert state if another ape detected a threat in the vicinity of your group. Hence our robust flight-or-fight response that floods your system with adrenaline if something goes bump in the night. But as for tracking the passing of time, it didn't really matter. The sun would rise, it would get lighter, and your body would wake up. | 6 |
8vgnc3 | Technology | how are we set to release 5G soon if we haven't acheived true 4G? | How many Gs do we need and when will we know when there can’t be anymore Gs to be had? | 9 |
63gj5k | Technology | Why do turn signals always flash at different rates? | It's a very simple circuit where a capacitor builds up a charge over x time then releases that charge over x time. Like a battery, capacitors don't all hold the exact same charge so their cycles are slightly off. Here is an explain it like I'm 10. URL_1 Here is an ELI5. Imagine the water is electricity and the bucket is your blinker. Imagine there are many buckets that are almost the same size but not exact. URL_0 The water buckets would be filling and emptying slightly differently. That's basically how the circuit works. | 2 |
cri21d | Economics | why do streaming companies give a discount if you pay for an an entire year vs. monthly? I understand why you get a discounted price per measurement on physical items, as a lot of the price is for packaging, but why does that same concept apply to streaming services where there is no physical product to package/deliver? | If you pay up front, they have that money in hand and can count on it in their profits, it goes in the bank and earns interest (for you, it wouldn't be much, but for a company with thousands of accounts, even a few cents adds up). Paying monthly, you cost them a little extra in bookkeeping, because they have to track did you pay them this month, how long until you have to pay them again, etc, and there's the possibility you may stop paying them, so they can't depend on your money coming in add reliably. So, discount for making their work easier. | 1 |
kigz4b | Biology | How am I able to blur my vision at will? i am a bit worried about doing it too much, does it do any harm if i do it too much? its is a new tic that just started and im scared it may do damage to my vision [here]( URL_0 ) there's a post that explains what i mean, i just want to know if it does any harm if i do too much? & #x200B; | When you say “at will” what part of your eye anatomy are you actually controlling? Are you merely changing the focus of your eyes? Because that is something that basically anyone can do and it is totally harmless. | 1 |
etplsy | Biology | Why you can still whisper if you have lost your voice but if you try to talk nothing come out? | Talking uses vibrations of your vocal cords. Whispering uses the same jaw, lip, and tongue movements to create speech, but only pushing air through open vocal cords. No vibrations = no voice. | 1 |
9wh4ft | Technology | How do lightning tracker websites work? Sitting on the toilet just now during a thunderstorm and a huge bolt of lightning flashed outside that must have been 2-3 miles away. I was watching the live lightning map on [ URL_1 ]( URL_0 ) and the flash that just saw was on my live map within 10 seconds! How is it possible to track the sky on a global scale like that? | /u/krystar78 describes the community data sharing, but as for the science: they use radio waves. The stations detect the VLF (very low frequency) radio signals emitted by lightning flashes, precisely measure the time the signal arrives, and use the speed of light to calculate a distance. By measuring the distance from several different observing stations, they can triangulate the lightning's position. You can watch the URL_2 system doing this in real-time here. Sometimes stations on the opposite side of the planet from the lightning strike will "hear" its radio pulse, just milliseconds later! URL_1 Info on the network: URL_0 | 2 |
7wttk0 | Other | What does the "in A minor" or "in D minor" in classical music songs mean? | If a piece of minor is in "A minor" or "D minor", it is telling you two things: (a) which is the tonal center, and (b) which is the quality. Both of them make "the key" of the piece and it isn't limited to classical music, modern songs (like a song by Led Zeppelin or Bruno Mars) are also in keys, but they don't include them in the title, *i.e.* Uptown Funk in D minor. A tonal center is the particular pitch where the song gravitates to, where it feels fully resolved, "at home". [Listen to this]( URL_1 ), the whole song gravitates towards A, if you were to end in any other chord, the song would feel unresolved, or incomplete. The tonal center is noted by the note letter, it can be any of the [twelve tones commonly found in western music]( URL_0 ). The quality is the "feel" of the song, so to speak. There are two qualities, major and minor, which one is being used depends on the set of notes that accompany the tonal center. With some ease, you can tell if a song is major because it feels "happy", and a minor song feel "sad". [Here you can listen to some songs]( URL_2 ) played in their original key and then they're transformed to the opposite quality, if the song is in G major, it then will be played in G minor. Some songs, like most blues, jazz, and funk, can't be quite contained inside a single quality because they're often using notes that are "outside" the original set of notes dictated by the key. In that case, the closest key is the one you have to notate in the music sheet. | 2 |
64n99i | Repost | Why are controversial moments in sport or politics dubbed "gate", e.g "towelgate" or "deflategate" | Um, because of watergate? EDIT: Oh right, most of reddit was born long after Watergate, forgot :) Well this happened, it was a thing: URL_0 | 1 |
bywmk6 | Engineering | Why are most eggs, egg shaped and some eggs are spherical? | Birds and most reptiles hold their eggs inside them for a longer period, resulting in eggs that are larger in comparison to their body than the eggs of things like fish and amphibians. So the traditional egg shape one thinks of associated with chicken eggs is mostly an adaptation necessary to fit through a comparatively small cloaca compared to the size of those eggs. For creatures like fish and amphibians, almost all development, including fertilization, occurs after the eggs are laid, so the egg can afford to be very small. And for a very small object, a spherical shape is the most efficient since it minimizes the amount of surface area per unit of volume. | 2 |
f7y67l | Other | How are calories measured? | Very basic explanation: They take a small amount of whatever food you are trying to measure the calories for and burn it inside a cylinder. The cylinder is surrounded by water. The heat from the food warms the water and they measure the temperature change. Based on how much the water temperature increases they give it a caloric value. | 2 |
bakpg8 | Other | what is traded in a nuclear trade deal? Isn't nuclear power a known science? | Mostly it's about fuel. Nuclear power (and weapons) are pretty well understood and, in many cases, even *simple* technologies. What's hard is enriching fissile material. You have to mine tons and tons of ore, refine it, then run it through a lot of very precise centrifuges for a long time to get a usable amount of fuel. A lot of the time, nuclear trade deals are actually lifting sanctions and/or other restrictions that would make it difficult for a country to process their own enriched fuel. They also often put up specific restrictions that make it hard to make weapons, like prohibiting the refinement of weapons-grade plutonium and requiring that certain byproducts be exported to certain countries. | 4 |
bztrp7 | Physics | What caused the sound associated with a balloon popping? Seemingly it would just be a balloon tearing, which is rubber and wouldn’t make much, if any, sound. | Sound is a pressure wave, when the balloon is inflated it had many times the normal atmospheric pressure. When you pop it, that pressure is released in all directions causing a sound wave | 1 |
jx9w4o | Physics | Why does it take such a massive amount of thrust to break free of Earth's gravity and enter orbit? I'm having trouble conceptually because it seems like it would actually become easier to escape gravity the further up into the atmosphere a rocket goes, since the effects of gravity and drag diminish with altitude. | Getting to orbit does NOT involve breaking free of gravity. There is basically the same amount of gravity in low earth orbit as there is at ground level. You get into orbit by going fast enough horizontally to where the trajectory that gravity pulls you down equals the curvature of the Earth, which means that for every foot gravity pulls you downward you've traveled far enough that the ground is now a foot further down than it was before. You never get any closer to the earth, and so you just keep going around and around. The hard part of getting into orbit isn't the altitude, it's reaching the horizontal speed necessary to orbit. It's VERY fast, and so it takes a lot of thrust to get there. | 1 |
6qvksf | Repost | When things are loading on my computer, why does the status bar often jump quickly to 99% and then stay there for a long time? | It can depend on what is being loaded. Sometimes, when you file transfer or download something the final step of the process is something called a "Cyclical Redundancy Check" or an "Integrity Check." When you download a file or an email, the place you are downloading the data will run what's called a hashing algorithm(SHA/MD5) against the file(s) you are downloading. The hashing algorithm will spit out a series of numbers and letters unique to that specific file or set of data and attach it to that data set or file. Once the step completes the download begins. SHA - Security Hashing Algorithm MD5 - Message Digest 5(although there may be more recent versions now.) At the 99% on your side of the download, the file has been received and the same algorithm is run again. The resulting series of numbers and letters that the algorithm on your end runs must match the original results that were generated on the other end of the download. This insures that the data has not changed in any way during the download process. Depending on the program you are using to download, it can also check for known hashes for that match malware. Example: You want to download a reddit app on your phone. Step 1. You connect select the app from the app store and tell it to download. Step 2. The app store accepts you request and runs the hash and spits out 12345 against the app. Step 3. The download begins Step 4. Your phone hits 99% and runs the same hashing process on the phone device itself. Step 5. The hash results show 12345 thus the integrity of the file is intact. Step 6. Install app | 3 |
b0qvqy | Economics | Why does denser housing construction seem to make housing prices go up? Shouldn't the opposite happen? Talking about in the US specifically. Cities with lower population and housing density seem to have lower housing costs compared to those with greater housing density (Ex\Houstin, Phoenix and Atlanta vs NY, DC, SF) | It's still supply vs. demand. And you've probably heard the saying, the three most important criteria for real estate are Location, Location, and Location. & #x200B; In the case of what you're talking about the price is going up because more people want to live there, necessitating a higher density of people. & #x200B; Cities where no one wants to live are always going to be cheaper and more spread out than cities where everyone wants to live. | 2 |
7k2hbi | Culture | What is the ideology of the political party 'Britian First' and how are they seen socially in england? | They're racist, xenophobic nationalists. They're seen as the lowest of the low by most people who have heard of them. The vast majority of people who show up to their rallies are there to protest against them. To be honest, most people have probably never heard of them. They're barely an active political party. | 3 |
6uof81 | Biology | How are people able to understand a language but not speak it? What happens in the brain? I was just with a friend and he talks English to his mum, but she speaks Polish to him. He understands everything, but can barely string a sentence together in Polish. (It's also not a pronunciation thing, he's good on that front). Surely after listening to a language for years, you should be able to speak it yourself? Especially as you have the vocabulary seeing as you understand everything. | This is just an anecdote, but I know a lot of Spanish words so when someone says a sentence in Spanish I can usually understand it through use of context. However, I was never formally taught how to speak Spanish, so I can't conjugate verbs or string together a sentence that makes much sense. I speak Spanish like a three year old child. Sure, I can say things like "Give me that sandwich" but I can't communicate on an adult level. Edit: If someone says the word "cerveza" I instantly know it means "beer". However, if I try to speak Spanish then I have to spend a few seconds searching my brain to find the right translation for every single word I am saying. It's too slow to communicate effectively. | 18 |
a1d7pz | Biology | Why are we not able to manually controll when to sleep but have to rely on the process of "falling asleep"? | The main modulators of sleep are the hormones melatonin and serotonin which are produced by a gland in your brain called the pineal gland. The interaction between these two will affect how quickly you get to bed and how good your sleep is. Basically the relationship between these two is quite complex but I’ll try and sum it up; Melatonin: used for “body clock” and feelings of tiredness. Is synthesised from serotonin. A lot of over the counter sleeping pills have this substance, and it essentially mimics what your brain would normally release. Serotonin; responsible for wakefulness and mood among other things. Has different effects (sometimes opposite) when In different parts of the brain. Some drugs that release serotonin (amphetamines) prevent people from getting to sleep. These are the 2 main components of regulating when you feel tired and you can’t really actively control them. However you also get build up of products during the day that eventually make you feel tired (e.g adenosine), which is why if you do a lot of strenuous exercise you will feel tired more quickly than not. Also there is some evidence to suggest that your blood sugar (measure of how well you’re fed) affects sleep. As well as other factors like being Iron deficient or anaemic. Sensors in your brain also integrate information such as light and sound subconsciously into your sleep cycle. This is why you’re told not to look at certain types of light, at night e.G laptops. They can prevent you from synthesising the correct hormones that you need to sleep. Basically there’s a lot of very intricate processes, and because of that there’s a lot you can’t control. However having good sleep hygiene can make a huge difference. | 3 |
7uobr1 | Culture | What is the difference between dubstep and brostep? I am very confused about the differences. I heard that brostep is usually “harder,” is that true? | You pretty much have it right. Brostep is a sub-genre of Dubstep, and Dubstep is much less specific. Really, the only requirements for something to be dubstep are to be ~140-150 BPM, have a 2-step drum pattern (except for Carnival, which is 4 on the floor) and have prominent bass. "Dubstep" has many subgenres, and when most people hear Dubstep they think of Brostep, which is dubstep but "hard" and "aggressive". I know that sounds vague but I don't have any other way to describe it. | 1 |
gmpns2 | Physics | Bell’s Spaceship Paradox I understand basic concepts like C as a constant and now some about relativity, but after watching numerous YouTube videos (which move much too quickly) and reading the Wiki article, I’m still pretty stumped. | Bell's paradox is a paradox because it utilizes a non-relativistic reference frame. This is a mistake, and the mistake causes a paradox. > Two spaceships connected by a thread accelerate to a relativistic interesting speed. The ships contract, but what about the distance between them, and what about the thread? This presumes the distance between the ships can somehow be "measured" by an independent bystander. That's not possible at relativistic speeds. What you can do is measure the distance with a light beam from ship A to ship B and back. This measurement will show that the distance and the thread are shorter, a classic Lorentz contraction. | 1 |
9ullug | Other | Insider trading is illegal. If someone comes to you, completely unsolicited and divulges nonpublic information that spell disaster for a company, would you be at fault if you were to try and exit the company at that point in time? | Technically/legally, it's probably not insider trading, although colloquiually most people would assume it is. While we often shorthand insider trading as anything that's "cheating", strictly speaking it's illegal because you're using someone else's info that you're obligated not to (ie, an employee insider trading is "stealing" from their employer), or you got a "personal benefit". However, a jury might convict you anyway, so there is still risk. The line is kind of fuzzy since it's kind of a terrible kludge. (Also, other countries have a much more common sense definition- the US is the outlier.) A wonderful (and funny) read on these sorts of scenarios is Matt Levine's articles on insider trading. Here's just a few: URL_0 URL_2 URL_1 | 5 |
elrn96 | Other | How do fish end up in new bodies of water that aren't connected to a previously existing body of water? | For some species like carp they'll swim across land during floods etc. For others, their eggs get caught up in winds, evaporation, birds etc and get carried to new waterways. | 1 |
ndetci | Physics | How exactly does electricity "know" to not flow backwards in a transmission line (or circuit)back to the source? Why does it move in one direction? | Think of it like water: water flows through the path of least resistance If you dump water out of a bucket at the top of a slope for example, it will flow downward, not necessarily in a straight path, but following areas that have less impediment Likewise, electricity will flow from higher voltage to lower voltage = there is higher voltage behind it and lower voltage in front of it. The system operates on a push-pull, tension-type approach. | 4 |
5uftef | Other | Why haven't we domesticated chimpanzees? It seems to me the utility of having quasi-human pets is so high that we should have been working towards this by now. | Some people tried to bring up a chimp just like a baby. A newborn chimp got sent to a family and they were treating him just like a normal baby. His name was Nim Chimpsky, you can google his wiki page, theres a lot about him. But! there is a certain comedy podcast that made an episode about him. It's super funny, you can check it out [here]( URL_0 ) | 12 |
9wpnmp | Physics | What does it mean when they say nothing existed before the big bang? | Actually the theory says nothing about nothing existing before the big bang. All we know is that from the way everything is moving now it appears as though if you rewind the clock everything started at the same point. So the theory really is that before the big bang everything in the universe existed in a tiny little space that was really really hot and then it just exploded and everything got spread out to how it is now. | 6 |
gbmecs | Biology | Do different species birds understanand each other? Does a sparrow understand a crow for an example? | There's a lotta mockingbirds on my block, sometimes a hawk will show up. The mockingbirds make a bunch of racket. Eventually, a bunch of crows will show up, and help them run off the hawk. On some level, that shows that the crows know what the mockingbirds are raising the alarm for. I thought it might be a coincidence but I've seen this multiple times | 7 |
6xhtie | Chemistry | What exactly is going when a ballpoint pen seems unwilling to write in one area of a piece of paper but writes just fine elsewhere? | You have to get the ball rolling so to speak. The way ball point pens work is by rolling a ball through ink then onto paper. Pen ink dries when exposed to air, this lets it flow onto the paper then stay there without smudging or making an outright mess, the ball serves not only to transfer the ink in a controlled manner but to seal the unused ink from air. The seal isn't complete though since there needs to be enough space for the ink to get out. When this ink dries it takes a fair bit of friction to break up the dried ink and free the ball to roll and the ink to flow. Even without dried ink there is still a minimum amount of friction that is needed to roll the ball, sometimes there are parts of the paper that are too smooth where as the rest of the paper is fine. | 3 |
5qp32o | Other | In a democracy, what is supposed to stop hypothetical 90% majority from literally killing off minority 10%? My first thought was the Constitution. But leaders elected by the majority can amend constitution and make new laws. So, ultimately, what stops majority rule from killing off (or persecuting) the minority if it was so inclined to? In other words, is there any *moral obligation* ANYWHERE in the tenets of le democracy? | There are several examples of this happening in democracies. The problem is that if you establish that killing off the minority is acceptable there is nothing stopping you from killing off the next minority, and the next, etc. In a working democracy a lot of people will fight for rights that does not apply to them because it may be their rights that is challenged next. | 14 |
c0azpw | Engineering | why MRI machines make so much noise. My boyfriend got an MRI of his brain the other day and will not stop talking about all the noises it made and has been obsessing over the “Why” of it. Can someone ELI5 so I can give him the answer he so desperately needs? | I think ICP said it best. “Magnets, how do they work?” | 4 |
6qjg5i | Biology | Why do humans need pillows and what would happen if we slept without them on a regular basis? Would this cause long term spinal problems? | [What about ancient civilizations that used neck rests instead of pillows?]( URL_0 ) I've seen plenty of these in museums, but didn't see this discussed here. I actually use something like this on occasion. When I take a nap in my car, using an empty water bottle (with the cap on to keep in air) under my neck really helps how I sleep. Of course, anything that keeps the natural curve of the neck would work too. | 20 |
7ldsfz | Other | How do flares stop missiles? | Heat-seeking missiles home in on the heat being generated by the jet's engine. Countermeasure flares are launched out of an aircraft and immediately ignite in a *very* hot flame. Now instead of seeing only one big hot target the missiles sees a dozen targets, and has to choose one. There is a constant battle between missile engineers and countermeasure engineers to design better and better systems. Missiles that can more accurately discriminate between an engine and a flare, and flares that can more accurately simulate the heat of an engine. | 5 |
bcqdl4 | Technology | How is the protocol UDP useful in gaming. I know it doesn’t check for missing packets, but how does that show in gaming (e.g. less lag...if so, how?) | TCP requires a back and forth conversation between a server and a client. If the client says they didn't get a packet it will ask for it again. And again. The server will try to send it whatever packets it needs. This can be really chatty but it does ensure both sides have the right packets. UDP protocol doesn't care if the other side got the packets. All that back and forth discussion, that TCP has, is overhead and can cause latency. UDP just sends new packets and anything that got lost is lost. For games (live broadcasts and other things) UDP is used frequently. In a game you don't necessarily want your computer doing that intensive "hey I sent you something. I didn't get it resend it. Okay I sent it again did you get it. Yes!" conversation for each packet. You just want the next one since the game is continuing. You'll see it in games where a player just teleports across the map. You lost those packets and your system just grabbed the next ones and put the character where it needed to go. You only care about what's happening right now on a game server. Same thing with live broadcasts. You may see it get garbled when you lose connection/packets but when you get it back you are still live. You don't waste time trying to recover those lost packets because those happened in the past. | 1 |
f2xtx2 | Technology | They say my phone has more computing power than the computers that got Apollo 11 to the moon. Does that mean, theoretically, my iPhone could orchestrate a moon landing from take off to touchdown? | Not really. That statement means that in terms of pure computational power - literally how much maths can be done in a certain time, your iPhone can do more and do it faster. But keep in mind that you're asking one computer to do all the work by itself (well, usually 2 to 8, because it actually had multiple computers (processors) running at the same time. NASA used many many computers simultaneously to do different jobs, and each had its own processor that it didn't have to share. The computers each had a specific function to perform, and didn't have to wait to process the data. There's no question your iPhone is more powerful than all those individual computers and even all of them combined. But there is the question is it able to process the data correctly. If your iPhone has a 4 processorvCPU and you need to execute 5 pieces of data simultaneously, you're out of luck. And maybe on your way to Mercury. Think of it this way: A Bugatti Chiron automobile generates 1,479 horsepower. This is more than 7 school buses combined. Does that mean it can get 400 kids to school every day? | 20 |
eti2xl | Biology | Why does our body feel so hot when we get increased body temperature by like 1-2 °C when everywhere else that increase in temperature is barely noticable? | Your body regulates its own internal temperature to keep it consistent. A small change in outside won’t change your internal temperature that easily since your body works very hard to maintain it. When your internal temperature changes e.g. because of a fever, it’s that times 1000 - this is what your body constantly tries to avoid by sweating. Maintaining correct internal temperature is very important for cell function, so 1-2 degrees is a big change. | 1 |
bb93qa | Biology | Why is hunger satisfied almost instantly? I understand your body needs to take time to convert food to energy but how come when Im hungry and I eat im not hungry anymore the second its swallowed? | This would be your reaction. It's not universal. It depends on your brain's reaction to signals from the stomach, mouth, and intestines (including those generated by your microbiome, i.e. bacteria and friends). Chewing gum sends signals to the brain from the mouth, which can temporarily hold off hunger pangs. This a surprisingly complex system. It also depends on how you define hunger. If hunger is a lack of satiation, then you will be hungry until your stomach says it has enough, which isn't the first bite. However, there is satisfaction from food that can counter hunger, even if only a little bit. Hunger can be your body's need for specific nutrients. You can have a full belly of rice, but still be hungry because you didn't get what you needed. Those pictures of pot-belly starving children shows this unfortunate phenomenon. Those kids are still starving after eating only bread. | 3 |
92v3zu | Biology | Only the biggest and strongest lions get to pass on their genes, so why do lions stay approximately the same size and strength? Why aren't they constantly getting bigger and stronger? | "Survival of the fittest" doesn't necessarily mean strongest. It actually means that the animal that can best fit into it's environment will survive | 12 |
5sbwxk | Other | What happened in the Superbowl and how did the losing team choke? | Falcons were playing guns blazing up until the half. Then, their fatigue and inexperience (playing @ Super Bowl) caught up with them and Patriots saw that and did what they do best. Win. | 1 |
7ft9x3 | Biology | Why does pain seem to shoot through our body in waves sometimes, why is not a consistent feeling? | Someone else might be able to give you a more complete answer, but it is related to the fact that we have different classes of nerve fibres running through our bodies, which operate at different speeds. The conduction speed of a nerve is mostly dependant on it being myelinated, which means insulted by fat and increases the conduction velocity. Our sensory nerves come in three categories - A, which are thickly myelinated and so carry signals very quickly; A delta, which are thinly myelinated so carry slower than A; and C fibres, which conduct relatively slowly as they have no myelination. Pain conduction is carried out mainly by C fibres, and by some A delta fibres. This is why you experience a sharp sensation when you first get hurt (A delta) followed by slower pain which can feels like throbs or waves, which come through the slower C fibres. | 1 |
672rb2 | Other | how are we able to consciously read while zoning out at the same time? You could be reading a book but then your mind starts to wander off about something completely different as you are reading each word and come to find that at the end of the page, you didn't take in anything you read. | So, I don't know for sure so don't quote me. But it could be tied to visual word form area. It's a part of the brain that develops as a direct result of learning to read. It has direct connections (via white matter tracts) to our auditory centers, motor planning, occipital, semantic hub, etc. So, when you see a word, you instantly know the word because of this region. Usually, the incoming visual stimulus has to go through the different areas of the occipital lobe that processes specific qualities about what you're seeing (retinotopy) but the VWFA just makes that whole process automatic (more or less) for text. I honestly don't remember what part(s) of the brain are active for sustained attention, maybe the parietal? Either way, if you're not paying attention you're not committing the incoming information to long-term memory. | 13 |
dffaue | Biology | how come sometimes the more you sleep the more tired you get? | How energized you feel when you wake up has nothing to do with how much you sleep, but has to do with when you wake up. When you sleep you go through [many stages of sleep]( URL_0 ). If you wake up when you're in deep sleep (stage 4), you feel like crap. If you wake up when you're in light sleep (stage 1), you feel refreshed. Each cycle is ~90 minutes, so many people recommend figuring out how long your cycles are and timing your sleep and wake up times to match your stage 1 sleep. | 3 |
gnfig6 | Physics | Why was/is e=mc2 such a revolutionary equation? | The operations of Einstein's E=mc2 pervade our universe. The sun itself can be seen as a giant pumping station, floating in space. Every second, millions of tonnes of hydrogen within it vanish from existence. In its place, great amounts of energy emerge: enough to heat our planet, and glow on through the solar system. Our very existence stems from the equation, for it also operates in "reverse". Not only does it say that mass can explode apart into energy, but energy can be squeezed tight to end up as ordinary mass. This means that if two beams of pure light are shined right at each other, solid particles can pop into existence where they collide. Ordinary torch beams won't be strong enough to do this. But when the universe was very young, it was filled only with light, carrying tremendous amounts of energy. | 4 |
kf55tl | Other | Why do cigarettes have to contain all the nasty carcinogens, toxic chemicals, and poisons that they do? Why can't people just smoke tobacco like they would marijuana? | All smoke contains carcinogens. However, it is true that cigarettes usually contain a number of additives besides tobacco, many of which may increase their unhealthiness. Some of these may be unintentional consequences of the cigarette manufacturing process, but others are intentionally added to the cigarettes by their manufacturers. This can be done for a variety of purposes, but generally speaking, the goal is to enhance the cigarette-smoking experience by doing things such as: * Affecting lung tissues in ways that increase the rate of nicotine absorption * Affecting mouth, throat, and trachea tissues to reduce irritation * Affecting taste * Affecting the rate of tobacco burn, so that cigarettes will self-extinguish if not actively smoked, to reduce the danger of starting housefires Many of these additives could have their own bad health effects beyond what burning tobacco by itself has. You can buy cigarettes that don't have any intentional additives, such as American Spirits, or you can of course roll your own using loose tobacco. But these aren't necessarily going to be significantly more healthy, because most of the carcinogens are in the tobacco smoke itself. | 5 |
kcf9tw | Biology | Why do people tend to adopt a lesser tolerance for sweet things as they get older? | As you are growing and developing calorie intake is vital for survival so there is a high priority for fatty and sugary food. As you get older your demand for high calorie food drops and the requirements for minerals and vitamins are key. | 3 |
hdxxxg | Other | Disney’s endless copyright I have two questions, how can a company like Disney own fairytales that they stole from folklore, doesn’t that fall under fair use or public domain? Also, how does Disney still own copyright for their characters pass the 50 year copyright statue of limitation? | Disney doesn't own the copyright to the fairy tale characters themselves; they own the copyrights to their versions of the characters. I can write my own Cinderella story today, for example, but I couldn't use the image or specific characteristics of Disney's Cinderella or the other characters, I couldn't use any of their songs, and I probably couldn't use plot elements that they introduced which weren't in the original (like, for example, the adorable talking mice). All they own is their *interpretation.* Don't get me wrong, Disney is famous for aggressively defending their copyrights and I wouldn't be surprised if they challenged someone using Cinderella (or whatever story), based on a couple of similarities that they can base a case on, simply because they have a lot of money and resources to fight with. But in theory, they don't own the rights to many of the original stories, whose characters would be public domain so long as you can prove that they bear no extra similarities to the Disney versions. | 3 |
7280ws | Biology | Why are drinks more “refreshing” or taste better (i.e. water) when cold? | It is cultural or personal preferences. In places like China, it is usually specified that you want chilled or iced water when ordered because some places will bring hot water. Some people like warm beer, iced coffee, warmed saki, cold soup, and other preferences that they feel tastes better. | 6 |
krn2uk | Physics | what is/causes airplane turbulence? I know I could easily google this question myself but I’m worried that the answer might be something that causes me to be afraid of it when I experience it in the future. Much like when you’re sick and google your symptoms and it jumps to cancer, I don’t want to google this and learn that every time I’m in a turbulent plane I’m likely going to crash and die. So I thought if it’s explained to me like I’m 5, I’ll get a straightforward answer but one that also assures me that there is no need to be afraid of flying either. | Sun heat ground. Ground heat air on top of it. Hot air go up. But not all ground heat air at same speed or intensity. So some air go up fast but some go up slow. That creates the bounces we call turbulence. Fun fact. Fly low in a smaller plane over the ground and get rocked by turbulence. Take it out over a large lake (Great Lakes or ocean) and watch the turbulence magically disappear bc that ground (water) will heat uniformly thus heating the air uniformly. | 2 |
5mpdop | Other | Why does orange juice from Tropicana taste different from Simply Orange if they're both 100% Orange Juice? I've taste tested both of these. They taste different, despite both saying 100% Orange Juice with no preservatives or additives. Neither has pulp, and both bottles were bought on the same day. | There are dozens of types of oranges: navels, tangelos, tangerines, temples, mercots, hamlins, valencias, parson brown, etc. Just like apples, every different type of orange looks and tastes a bit different. Some are better for eating fresh and some are better for juice. Some are very popular, some are not as popular, and some are cheap since there is a huge supply and some are expensive. Some are grown in Florida, some in California, and some in Brazil. So every manufacturer sources their oranges from a different place and of course that makes them taste a bit different. And as other posters mentioned, December is the main time for oranges to be harvested, with some a bit before that to a bit after that. Freezes can damage or reduce the crop forcing juice manufacturers to change the mix of oranges they use. Since we need orange juice year round, some manufactures put the juice in giant oxygen-free holding tanks at 33 degrees and keep it there for up to six months. This damages the taste so they add in "flavor packs" which are also made from orange oils (which I think is somehow distilled out of the orange peels, but I'm not really sure). So you can see, there are hundreds of variables which go into how orange juice tastes, and the big companies spend tons of money making sure that their juice tastes the same no matter what time of year it is, or what materials they have to make it with. | 15 |
67zl41 | Economics | How are counterfeit bills smaller than $20 prevented from entering circulation? I reckon a good counterfeit $10 would go unspotted for a while. How would we know if we are in possession of one? | Here's another question. When the business goes to the bank, who takes the hit? The business because the bank doesn't recognize the bill as legal tender? I'd be interested in knowing the answer if anybody knows | 30 |
eluost | Biology | How does your body burn 2000 calories a day, but you have to run a mile to burn 100 extra? Basically the title. I saw this thing about how much you have to exercise to burn off certain foods and was wondering how your body burns so many calories by doing nothing. | The normal processes running in the background use up the majority of your resources, running a few other programs for an hour or so only takes a little bit of extra. You're normal every day survival is basically like chrome. | 24 |
hq4w3f | Other | Is there more than a 4th wall? I think I know what the 4th wall is, it's like an imaginary wall that separates the audience from the story of the characters in the television, as it has become more common with movies like Blank-pool and show's like Rick and Morty "breaking the 4th wall." I don't know why I haven't really thought of it until recently, but I've been wondering what exactly are the 1st, 2nd, and 3rd walls? And does it go farther than the 4th wall, or does it stop there and why? | The idea came from the sets of plays, where you'd have the back and two side walls of a house, but no "fourth wall" that would complete that house, as that would keep the audience from seeing the action. | 1 |
hpl9cc | Engineering | "Why do Torque Wrenches use Nm?" Would someone explain how torque wrenches use this unit of measure? it doesn't seem to apply as a newton is a measure of acceleration and a torque wrench is used to set a specific amount of twisting force (to a bolt or nut for example). How long it takes to turn the torque wrench is not part of using it. The Newton would imply that it is. a gram/meter or kilogram/meter I would understand. Like the lbFt, they measures how much pressure is applied at a specific distance from the center of rotation. | Newton is a measure of *force*, not acceleration. The newton-meter is the standard measurement of torque. If a torque wrench is set to 1 Nm, then this means that it will slip when you apply 1 newton of force one meter down the handle of the wrench, or half a newton at a distance of two meters, or two newtons at half a meter. | 2 |
nb8i2z | Chemistry | What does the weather forecaster mean by dewpoint? How does it relate to humidity? | There is pretty much always water in the air. Humidity tells us how much water is in the air, relative to how much *could be* in the air. The amount of water that *could be* in the air depends upon the temperature of the air. So, let's say it's 75 degrees out and the humidity is 80%. If the temperature dropped, the humidity percentage would go up, even if the actual amount of water in the air did not, since the maximum amount of water that *could be* in the air has decreased. So, what happens when the air cools down so much that it hits 100% humidity? If it cooled down any more, there would be more water than the air can hold. At this point, the water in the air drops out as a liquid, forming fog or dew or rain, so that the humidity never rises above 100%. The temperature where this happens is the dew point. For almost any amount of water in the air, there is a temperature where it will reach 100% humidity and liquify. So, for any humidity/temperature pair, there is a dew point where the water in the air will start to drop out. | 2 |
5uqm17 | Technology | When you turn the volume up on a radio or tv, what actually happens to the soundwaves? | An amplifier does not generally have adjustable gain at a circuit level. In other words when you create a circuit that amplifies a signal, it amplifies it a set amount, and adjusting the volume knob doesn't change these physical properties of the circuit. So most volume control is handled using either a potentiometer, a digital mixer, or a relay/stepper system. Potentiometers or volume pots are the most simple. It's a resistor that increases or decreases resistance as the knob is turned. The downside is that they can be fouled by dust, grime, grease, and wear and tear. If you've ever adjusted the volume knob on something and heard scratchy static, that's what you were hearing. Digital mixers adjust the output level in the digital domain. For instance in a 16bit PCM sound sample, 65,356 is the decimal value for the loudest possible sound IE the highest analog voltage. If you want to lower the output voltage, you simply subtract from that digital value and the DAC or digital to analog converter, simply goes with the lower and quieter number. The windows volume adjustment in your taskbar is an example of this. Lastly you have relay volumes which step through combinations of resistance by changing the path the signal takes through a circuit, causing it to increase or decrease at regular intervals depending on the state of the relays. They are complicated but offer a good compromise of actual voltage adjustment, without suffering from noise and dust. So you have your source, which could be a record player, or a CD player (DAC chip) which outputs at 0 to 2 volts usually which is too low to hear with headphones or speakers. That signal goes into a pre-amplifier which is where the volume control is usually done. This adjusts the voltages before they go to the final output stage which is the main amplifier. Then the main amplifier amplifies the signal however much it was designed to and a quieter pre-amp source causes lower volume, and a higher pre-amp source causes louder volume. | 2 |
das4f5 | Biology | What happens when someone goes into an unplanned surgery (eg. after accident) with full anesthesia having eaten in the last few hours? I know that the reason for the fasting is because during full anesthesia, the body muscles including tje stomach relax and this might cause stomach acid to go to the lungs. | Yes, that’s still a concern, but it’s simply made irrelevant by the higher priority of the fact that if they don’t get this surgery they’ll die. The chance of a complication is outweighed by the certainty of death. | 4 |
l2ktr0 | Other | Why does money always take a few days to arrive when you send it to a bank account. And why can you sometimes send it instantly and sometimes not? Thanks :) | If the accounts are held in the same bank, transfers are usually immediate. If not, the transaction is usually sent for clearing which might be batched at the end of the day. What happens depends on the systems in the particular country. International transfers will take even more time. Of course, the cynical response is that there is no direct incentive (other than customer satisfaction and marketing) for a bank to want to speed this up for standard account holders. When you are sending money, the money is deducted immediately from your account (or put on hold) and the recipient doesn't necessarily get access to those funds until a few days later. Note: the US is a bit primitive in some respects, many countries have systems that allow for nearly immediate fund transfers between accounts at different banks at very low cost. EDIT: assuming you are in the US. | 1 |
ez4h7p | Physics | why jumping on top of a moving train is not like jumping inside it? Imagine you’re on top of a moving train, if you jump, you won’t land at the same spot before the jump, but you’ll land behind where you jumped and you may even fall. But when you’re inside you’ll land in the same spot. I don’t understand that. | Air resistance brother. Take the train out of the equation. Throw a basketball straight up inside a gym, comes straight down. Next time you got some 40mph winds throw it straight up while outside, you will be chasing it. | 3 |
dc2c3b | Other | Is there an objective reason why people keep encountering / noticing the same number sequence over and over again? Is there any sort of psychological effect that can explain this? Not numerological/astrological or whatever other superfiction, but more like a cognitive bias of some sort. For example, I keep seeing 14:47 on the clock almost every day, in the different documents (14.47, 1.447, etc.). | Confirmation bias. How many times do you look at a clock throughout the day? Probably a lot. But you dont mentally take note of the significance of the time (unless it is the time you have mentioned) because our brains would become too overburdened by taking note *of the ordinary* Its only when something out of the norm happens that you stop and take note, so when you think back, you only recall what stood out to you. | 1 |
l6ptb7 | Economics | what is a hedge-fund? I’ve been trying to follow the Wall Street bets situations, but I can’t find a simple definition of hedge funds. Help? | A hedge fund is a kind of investment firm that specializes in low risk, high dollar trading. Only profitable if you are VERY rich or representing some kind of group fund. The name comes from the practice of doing paired, opposing bets to reduce risk. Say you bet a lot that Tesla does well this year, but also bet a little on the off chance they do poorly. You're literally hedging your bets. | 15 |
c7bj28 | Other | Why is it that, when someone tells you to do something, you want to do it less? | Funnily enough, I feel the complete opposite at work. It usually gets slow so there’s nothing to do but stand at the register, so when a manager asks me to do anything I hop to it. Otherwise time moves hella slow | 18 |
mejqxz | Engineering | . How do seatbelts know when to lock?? | I'd like to add though it is not in the realm of your question exactly, I recently learned that because of the locking function it will leave a stretch mark in the belt during a crash and investigators use this mark to determine if the driver or passenger was wearing their seat belt. The marks can also correspond to a mark on the person's body like a bruise. This can help determine who was the driver, like if they switched places with the passenger to avoid charges or some such reason. | 4 |
8emg49 | Technology | what SAP does for companies? [SAP]( URL_0 ) is the biggest software company come out of europe for sure. but what it does? compaies use it for what? | It's software that help connect all of the business functions together, so sales, payroll, inventory, and other information are all in one place to help management get a better complete picture of what is going on. In theory anyway, it's ridiculously hard to set up and even then it's never really "done" being set up . . . | 4 |
f89oqz | Engineering | Why does electricity appear blue but sparks from electricity are yellow-ish Orange Driving down the road yesterday they were repairing some electrical lines and I guess one of them sparked and it left a trail of blue sparks on the ground. But when I hook up a battery and short it with a wire sparks appear an orangish-yellow color. Anyone know why? | blue = glowing nitrogen (high voltage through a stable gas makes it glow - this is how fluorescent lights and Neon signs work) orange = Burning oxygen & #x200B; Electrical arcs are blue, because they go through the air and make it glow, and since the air is mostly nitrogen, you get nitrogen blue. & #x200B; When you hook up a battery you should see both blue AND orange sparks, blue as you get close, and then orange after contact, because the orange sparks are from oxygen, a fuel source, and heat all meeting to create combustion together. | 6 |
m9a19y | Chemistry | Why water feels soft in some houses and hard in others? Is it minerals? Some places the water just feels so soft during a shower or when washing your hands. Other places, especially old buildings the water can feel a lot less comfy when washing your hands etc. Why is this? | Along with mineral content having different feels, it can also be the type of aerator or sprayer. Adding air bubbles to the water make it "softer" and better at "wetting" surfaces than a solid stream of just water (which has a single surface tension rather than one subdivided/perforated/weakened by air). Also air bubbles added to water underneath a floating object such as a boat, will cause the item to sink quite rapidly. Structural integrity of the surface tension is destroyed by subdivision (aside from air compresses and water doesn't, so bubbly water is "extra squishy" and can't carry loads). | 3 |
fm69ce | Technology | When you put two phones or radios next to each other and start a call between then they make a loud ringing sound why is that | It is a feedback loop. Basically, there is some noise, be it interference, someone's voice, footsteps, etc. This is broadcast from the speaker of one device at a slightly amplified level. The other device recurved it, then plays it back again at a more amplified level. The two go back and forth like this over and over again, each time raising the volume. | 1 |
5pfk9x | Physics | How can the living cells in our body be made up of molecules that in turn are made up of non-living atoms? | The same way that my computer monitor is made up of little tiny dots of silicon and glass at one level, but at another level is showing a beautiful painting. It's all in the level of detail at which you wish to look, and the *organization* and *interaction* among the component pieces. If I just took a random 34982439823098298 pieces of silicon and glass and plopped them on a table, I'd never get anything resembling my computer monitor. If I put them in a very specific pattern, however, and let the system operate over time, and give it energy that it can consume, I get pictures or websites, or whatever. The definition of "life" is somewhat fluid, but generally requires that an entity react to its environment, consume resources, excrete waste, and be able to reproduce. No individual atoms can do that, but specific organizations of them (e.g. what we call "living" cells) can, via chemical reactions. | 3 |
dyxxjd | Biology | iS the voice we hear 'talking' in our head the brain itself? Or is it just another part of our brain? | And it’s absolutely fine that mine is more of a dialogue, eh... right? Yeah all good, ya. We are grateful for that validation. Ta. | 5 |
6zde8l | Biology | If all of the cells in our body (including our brain) are constantly being replaced, how is our consciousness still "us"? | That's an interesting and unanswered philosophical question. When you wake up, are you the same person that went to bed? From a biological perspective, who you are is constantly changing. But the individual doesn't exist any one part of the body, we arise from the *pattern* of cell activity--including the brain but also the hormone system and so on. New cells mostly organize themselves to take part in that pattern, though it's never identical from one moment to the next. Think of it like adding or removing instruments to a song, or changing the key; it's different, but there's a recognizable continuity of the essential pattern. | 2 |
c5up82 | Culture | Aaarrrr there reasons why we think pirates sounded like this? | It comes from the depiction of Long John Silver by the actor Robert Newton in the 1950 Disney film adaptation of 'Treasure Island.' | 8 |
gvaqaf | Technology | Why do you need to change your password when you forget it? I'd much prefer to just be reminded of it by email, for curiosity and for convenience. | 1. For security reasons, they don't actually store your password. They store a thing called a hash. When you input your password into a website, the website actually generates the hash and compares it to what the website has on file, not your actual password. It is practically impossible to recover the original password from the hash. 2. They would have to send you your password over plain text in an e-mail which is an insecure delivery method for anything but a one-time password (and even that is not a good practice). 3. Also, if you forgot it, then it really wasn't a good password as passwords should be easily remembered so you aren't tempted to write them down. As an alternative, you can have hard-to-remember passwords in conjunction with something like a password manager, eliminating the need to remember lots of different passwords. | 5 |
nv8hgb | Biology | How do flavors work? I was sharing a can of bacon flavored pringles at work with some coworkers and we got into discussing the different types of "weird" flavored chips we've eaten. Cheeseburger flavor, taco flavor, and oven roasted chicken flavor, pizza flavor, etc. How the heck do they manage to get the chip to taste like a cheeseburger? Bread, cheese, meat, and all? How? | Flavor all comes down to two basic things (as far as I'm aware): chemical composition, and temperature (this affects the movement of the molecules). If a scientist is able to break down the general composition of a cheeseburger to the basic elements and then create a flavor powder that contains most of the more important chemicals, then with a little bit of psychological suggestion people will taste what they are told it's supposed to taste like. Generally speaking, the more complex flavors like oven roasted chicken or pizza you wouldn't associate with those foods if you were blind tasting the product. For the oven roasted chicken you might think it's chicken broth flavored and for pizza you might think it's tomato and cheese flavored. | 2 |
mi0ez4 | Physics | Why does smoke travel the way it does? What determines it’s “shape?” | It simply is carried along with wind. Smoke from fire typically rises because the air containing the smoke has been heated by the fire, making it less dense than surrounding air which subsequently pushes it upward. | 1 |
lxi0at | Technology | How can themeparks snap a crystal clear picture of you on a rollercoaster going 70mph | They can use a fast shutter speed because they have the flash lights. If the lights didnt flash when you went past there wouldn't be enough light hitting the lense in the time you were there, so the image would be dark. If the shutter speed is lower you get motion blur. | 5 |