q_id
stringlengths 6
6
| category
stringclasses 12
values | question
stringlengths 5
4.6k
| reponses
stringlengths 28
9.92k
| response_number
int64 1
489
|
|---|---|---|---|---|
mlhr6m | Other | Why social credit score system is such a bad idea? | Once a system like that is implemented it has a very high potential to slowly get changed into a tool for maintaining control and power by adding or changing the definitions of whats "good behavior". If people become dependent on social credit to live a functional life, and social credit is dictated by the State's criteria, then you are de facto beholden to behave as the state sees fit in order to live a functional life. If a a corrupt administration gains control it just becomes one more tool they can use to coerce people. No more protest or dissent, no more free speech etc. | 5 |
8aq1nw | Other | Why are barrel bombs so bad? | In short, barrel bombs are only really good at killing noncombatants in cities. They work well on military bases and in confined combat areas, too, but in cities they mostly kill civilians. They don't penetrate armor or break defenses. They just make everything burn and make the area uninhabitable for anyone not in a military vehicle or a bunker. | 5 |
bjxhtq | Biology | what is happening when doing nothing out of the ordinary and a ringing just starts in one ear and eventually fades? | This specifically is called "sudden-onset ringing tinnitus" and is caused by a temporary misadjustment in the way our inner ear amplifies quiet sounds. A high frequency is briefly set to over-amplify, but it takes a little while for the setting to be turned back down. This "turn it down" response accounts for the "cotton in my ears" feeling one sometimes gets when the ringing ends. This is a common occurrence, unrelated to age or injury. | 6 |
86dcs2 | Chemistry | Why are almost all flavored liquors uniformly 35% alcohol content, while their unflavored counterparts are almost all uniformly 40% alcohol content? | Taxes are part of the equation. The legal minimum for a lot of spirits is 40% ABV. You get taxed on the ABV of your product by the federal government. 5% less ABV could be millions of dollars excise tax savings. Supply and demand is another. If people will consume 35% ABV products, why not sell it to them at that rate? More water in the bottle and less excise tax. EDIT: To be more correct, you are taxed on the total amount of alcohol in the bottle. A 1.75L bottle and a 750ml bottle each at 40% ABV will be taxed differently as there is more alcohol in the 1.75L bottle. | 9 |
kxg2ka | Biology | How does blood circulate through your body after you've had an amputation? | You can kind of think of arteries carrying blood from the heart, and veins carrying blood back, as the two legs or sides of a ladder, with smaller arteries and veins, that branch off and connect via capillaries as kind of like the rungs. So blood flows up one side of the ladder, but at every rung, some blood crosses over to the other side, and starts to flow back. If you cut off the top part of the ladder so that several rungs are gone, the blood can still cross over at all the lower rungs. Also large vessels have some ability to narrow themselves and reduce flow, if they don't need to carry as much blood, and the smallest vessels can actually remodel and reroute themselves after a major disruption like an amputation or a bone graft or whatever, to make sure all areas of body tissue get the right amount of blood delivered. | 2 |
ipmxu9 | Physics | Why does the sun sometimes look red during sunrise or sunset? | When the sun is directly over head, blue light scatters more easily than red in the atmosphere, turning the sky blue. The same thing happens as the sun rises and sets, except that there's more atmosphere between the sun and you, so the blue light scatters too much, and you're left with the yellow/red light that makes up a sunset/sunrise. | 2 |
7e7e0a | Technology | How do old TV shows change their Aspect Ratio to 16:9? I was watching old Sitcoms and Cartoons, and noticed that alot of these have been 'converted' to the 16:9 aspect ratio. While their were originally shown in the 4:3 aspect ratio. The newer versions with the 16:9 aspect ratio don't look like they've been stretched or extremely cropped, but are still wider and have more background. How is this possible? | That largely depends on how the initial shows were shot. A lot of television dramas from the 90s, like ER or like X-Files, were shot on 35 mm film which usually has a default aspect ratio of 3:2 (which is larger than the aspect ratio of 4:3 that we consider to be full-screen). So while those dramas were broadcasted in 4:3 and even framed and directed as if it was 4:3, its source imagery is going to be 3:2 which can be easily converted in 16:9 for homevideo- or streaming-use. | 2 |
5s1nc0 | Biology | Why do obese people starve to death before they are super skinny? Why the body doesn't use that fat energy? | [If the body receives it's necessary vitamins/nutrients in addition to enough water, it's possible to basically "starve" for prolonged periods of time.]( URL_0 ) Therefore, if an obese person dies while fasting before they are super skinny, it is not due to starvation. | 10 |
6mv87h | Economics | how does homelessness cost cities money? I've come across articles in the past about cities saving money by offering housing to the homeless. What is it about homeless populations that cost money in the first place? How does building and maintaining housing cost less then letting them wander the city? | They have a tendency to make public disturbances which have to be broken up by law enforcement. They defecate and urinate in the streets and alleys requiring them to be cleaned. They utilize publicly funded homeless shelters and soup kitchens. If the homeless are not there these things are not needed. They utilize emergency medical care with no ability to pay. The idea of getting actual housing is in tandem with getting them actual jobs. They have extremely cheap minimal housing that gives them a stable safe address and the ability to seek employment. Which which they pay rents and taxes. | 4 |
7vkar9 | Biology | That sharp pain in your neck followed by a burning feeling after a wrong move with your head. | Short answer - You pinched a nerve. The sudden sensation of heat is usually a nerve response. So, if you move your neck a certain way and suddenly feel a rush of heat, you probably pinched a nerve. That doesn't necessarily mean that you "have a pinched nerve" in the sense most people mean (though it's totally possible. How long the symptoms last are a big indicator.) Degeneration of the discs or vertebrae or a direct injury can cause long term nerve impingement and damage. What I think you are describing is a short term pinch, like hitting your "funny bone" - which is actually your ulnar nerve. Anyway, if your neck is unusually tight, you are more susceptible to fiery, hot "kinks". Alternating hot/cold therapy, stretching and being aware of how you sleep can make a huge difference. Edit to add - every nerve that leaves your spine is surrounded by fascia, connective tissue and muscle. Those muscles that you can feel with your fingers along either side of your spine are really groups of much smaller muscles. If some of them are tight and you unknowingly move in a direction that puts stress on them, it hurts. If you pull those tight muscles too far, they could "tear" (sprains and strains are various degrees of tears). Your body works quickly to protect it against injury and will seize up neighboring muscles to offer stability. This all happens quickly - and most of you probably experience it in your low back as well. The two least stable areas of the spine are in the cervical and lumbar regions. When this happens, there are lots of nerves that can be caught in the cross fire and when they do, they will make you feel heat, sharp stabs, pins and needles, wetness or even electric shocks. But basically, the muscles and connective tissue that sandwich a nerve have seized up and the nerve in between them got pinched. Now that I finally typed that sentence out, I'm gonna copy/paste it to the top of my comment. Edit to reply to the sleeping part - First, never sleep on your belly. This kills the neck. Side sleeping is hard on your neck, shoulders and hips, too though. It is really hard to train yourself to sleep on your back, but it is the best way to sleep for your body. You need to have a low profile pillow for your neck, but your mid back and shoulders feel much more comfortable if they are slightly raised. Think wedge or a reclined position. Then your low back needs support, too. But you do that by supporting your knees! Sounds off, but it's true. Placing a pillow under your knees will change the angle where the femur inserts into the pelvis and therefore the pressure applied to the SI Joint - that's where your sacrum meets up with the top of your hip bones, which is the area most people point to as "low back pain". Anyway, I get that it sounds daunting and impossible, but it isn't. I'm a massage therapist and I give this same advice to lots of people. Some of them are no-fuss types who just throw away the pillows and force themselves to sleep on their backs. Done. (Rare, but they are out there). Some are more creative and they buy memory foam wedges to give them some lift under their mid back and shoulders, then stack a very thin pillow under their head/neck and put a body pillow under their knees. Others (like me) decide to throw a fuck ton of money at it and buy one of those beds that raises and lowers like a hospital bed. I went to school for massage therapy almost 10 years ago and while I was there, we learned a lot about postures and dysfunctional movement patterns that contribute to chronic pain. Before then, I had chronic shoulder and neck pain as an exclusive side sleeper. When I started addressing the way I sleep and either received regular massage or self-treated, I pretty much solved my pain issues. I still wake up on my side from time to time, but then I just roll back onto my back and go back to sleep. It takes years! But it's worth it. And, can I add that regular massage therapy is a great way to help manage pain!?!? It's not just a luxury for wealthy vacationers. 95% of my clients are regulars who come in to keep their pain at bay. I have truck drivers, carpenters, athletes, mail carriers, hair dressers, office workers*. It just so happens that massage therapy also feels good, so there's a bonus to using it as a tool for optimal health. Give it a try. *office workers - jutting your chin slightly forward to see the computer screen tightens up the suboccypital muscles at the base of the skull and can cause headaches. Also - the mouse hand - I often see chronic shoulder pain that seems like it is underneath the shoulder blade where you just never can quite reach it. Then pain/numbness will sometimes spread to the chest and/or down the arm and into the thumb and first couple of fingers. That's referral pain from the scalenes! Google "trigger point referral pain scalenes" and see if that pain pattern doesn't look familiar. Switching your mouse to the other side for a few weeks and getting a good massage can fix that. I'll stop now, but man, I could talk about bodywork all day LOL Ok, I have some time before I need to go to work, so I'll give you all a quick lesson on muscle tension. When I get a client who wants to try to self manage their muscle tension at home, they always ask "what are muscle knots, what causes them and how I get rid of them and/or stop them from coming back?" So here's how I try to explain it - First, imagine that you have long hair that's tied up in a tight ponytail. You get caught in the rain and after you run into the house you take your hair down to find that the outer layer is soaking wet but the inner layer is bone dry. The water can't really seep through where the hair was tightly bound by the rubber band. Your muscles are the same way. They are made up of lots of long muscle fibers very much like that ponytail. Now, here's the part that sounds crazy. When your muscles contract, those fibers attach to each other and kind of "choke up" to get a better grip. The contraction is automatic and the act of releasing that grip requires energy. "What!?!? It takes strength and energy to lift something, so the contraction should require energy and the release is when you relax and let go. Right?" Nope. Sorry, but it's the opposite. For a good example of this, think about rigor mortis. After a body dies and the muscle fibers stop receiving the oxygen and nutrients they need, they go into a permanent state of contraction. That's because they stopped receiving the energy they require to "let go". So, contraction is automatic and the release requires energy. Got it. That energy comes in via fluid, right? So, in order for a cell to receive the nutrients it needs, do its job and then create waste that also needs to be taken away, it needs to have fluid coming in and going out. We call this cellular respiration. In order to work properly, your muscles need a constant flow of fluid into the deepest fibers. If they are over used, the deepest fibers might not get the nutrients they need to release. This is what "muscles knots" are. So now, understanding what causes these "knots", it's easier to come up with ways to treat them. The first and fastest solution is to use brute force and manually separate the fibers to let the fluid in - as if you're trying to help get the center of that ponytail soaking wet while standing in the shower. But brute force can be very painful and, depending on the location, not really safe to do without proper training. For this you can hire a qualified massage therapist. Other, gentler ways include heat and ice. Heat will open up the capillaries and encourage a rush of blood into the area locally. Think of this as a soak in the tub instead of standing under the shower. Most people are familiar with how relieving heat can feel. The trouble is, though, that most people stop there. They open up all the things and get good blood flow into the area and then just leave it there. They forget how important it is to "exhale". Complete cellular respiration requires an inhale and an exhale. Drawing all that fluid in and then leaving it there can contribute to inflammation and result in more pain. Following up with cold therapy will push the fluid out. So my recommendation is to always start with hot and end with cold. Ice is no longer just for a sprained ankle! (Make an ice pack with a tube sock and rice. It has the same therapeutic value as ice with a less jarring, icey feeling) Repeat this cycle with some light stretching and I promise you'll notice a significant difference. And, speaking of pushing fluid in and out, it makes sense to hear that this whole process works much better if you're well hydrated, right? This is why hydration matters for muscle pain. If your rivers are dry, they can't bring in nutrients and remove waste, right? So help your body out by making sure it's well hydrated and can do it's jobs properly. | 10 |
6p8i29 | Economics | Why do doctors in the US seem like they're always over-booked with patients when there are huge waiting lists for people that want to go to medical school and become doctors? | It's really just supply and demand. The Wall Street Journal [reported]( URL_0 ) a decline in the number of doctors per capita and the American Association of Medical Colleges [predicted]( URL_1 ) a shortage of approximately 46,000 specialists and 45,000 primary care doctors by 2020. Additionally, the gov't gives authority to private medical boards to do things like issue medical licenses. There's a political process for the public to resolve complaints with public regulatory bodies but not state-appointed private ones. The Medical Board of California is an example. When there's few qualified doctors and quasi-private regulatory agencies restricting licensing, you're gonna see long wait times, high prices, etc. The doctors that practice now have sort of a baby monopoly in that their competition is artificially small and so they can get by offering a shitty service for high prices bc there isn't a bunch of newly licensed doctors. A doctor fresh out of college has to offer a cheaper price or a better service (e.g. short wait times) to incentivize people to use his service as opposed to the service of his more experienced peers. Without the new doctors coming in to the profession at the rate the demand merits, the already established doctors don't have as much of a reason to provide a great service as they dont have anything to lose providing a bad one | 3 |
cz048w | Other | - Why fibercloth is called fibercloth and what makes it so special for cleaning smudges of glass surfaces so good? Why other pieces of cloths cant do it properly? | I'm not sure if it's because English isn't your native language or if you've just been interpreting things incorrectly but I think you're talking about [microfiber]( URL_0 ) cloth - a cloth made from microfibers - rather than a tiny "fibercloth" (if that's even a thing). In short, a microfiber cloth is made up of a bunch of *really tiny* fibers which give you a massive amount of surface area for wiping an absorbing things (like oil smudges on your glasses). | 1 |
83emip | Other | why a helicopter can’t drop me on the top of Mount Everest | Pretend to be you having to get up in three different situations. One is a high ledge, two is a swimming pool and three is the air. When you want to get up a high ledge you can use your hands and arms to get up there. You are essentially trying to push the ledge down and in the process, because obviously you cant push a ledge down, your body goes up. In a swimming pool you essentially do the same. You push the water down in order to get up yourself. You can try to do the same in the air, but there is not enough resistance in the air to get you up. Without getting in too much detail, you can't push down the air in a same way a bird can, so you can't push the air down in order to lift yourself of the ground. This is in essence how a helicopter works. A helicopter flying beneath a certain altitude is like you swimming in water. The helicopter's wings can create enough lift by pushing the air down. How higher you go, how thinner the air gets. Essentially it will become harder to push air downwards and that way creating lift. There comes a point where a helicopter can't push enough air downwards so it cant climb any higher. In the same way as when you reach the surface of the water, you can't swim yourself into the air. Mount Everest is too high. | 3 |
gi1r65 | Biology | Why is it that, like in action movies, when you break someone's neck they die? Isn't it just like breaking your arm? I know there's your medula there, but why does it kill you? | Depending on how the break occurs, a spinal cord injury can paralyze your lungs. Even if this doesn't happen, most neck breaking grips also allow pressure on the windpipe and carotid arteries. Enough pressure on either is fatal. | 4 |
ebaegl | Repost | Why aren't illegal activities recorded in documentaries/youtube videos/any media prosecuted? | I have irrefutable proof on film that Arnold Schwarzenegger is a mass murdering robot from the future. Why haven't the police arrested him? Admitting something to a reporter is rarely, by itself, suitable grounds for prosecution. All your lawyer has to say is "he was lying because he wanted to be on TV". | 11 |
8unnl7 | Chemistry | Why doesn’t salt water keep a person hydrated even though sodium helps retain water? | The concentration of sodium in the water creates osmotic pressure on water molecules inside the body pulling them out into the consumed salt water to balance pressure. There is a lot more sodium in a glass of salt water than your body needs or can absorb. | 2 |
cbmw88 | Biology | Where does the bacteria that helps us digest come from? Are they generated from the body itself? What distinguishes it from a regular 'alien' bacteria? | Our microbiota (the collective term for all of the organisms that live on or in our bodies) come from the environment. Our bodies don't "make" bacteria and they can't just pop into existence from nothing. The very first of our gut flora enters our bodies right as we're born. As we emerge from the birth canal, all of our mother's vaginal flora (bacteria that live in the vagina) as well as bacteria on her skin around her pelvis goes into our mouths, and beings colonizing our digestive tract. Breast milk also has beneficial bacteria in it that colonize our digestive tracts as we consume it. The only distinction is whether or not they make us sick. The bacteria that live in our guts are actually good for us (or in some cases, not beneficial but not bad), and crowd out bad bacteria from taking hold. Everyone has a different gut flora, but there are are some common types that are found in almost everyone like *lactobacillus* and *bifidobacterium*. | 1 |
5wn9s6 | Biology | Why is heroin and meth so addicting? I find the subject of addiction so fascinating, like why would someone destroy their lives for a gram or two of these substances? | Bruce Alexander, a psychologist, conducted a study in the late 1970s where he challenged that the addictive hooks in the chemicals of heroine were what made people addicted. He looked at the experiment where they placed two water bottles in the cage and nothing else. He basically came to the conclusion that the rats had nothing to do. So he built rat park. It was basically a rat community that had everything a rat would need to be happy and content including members of the opposite sex. He had two water bottles in it. One clean and one laced with heroine. The rats almost exclusively drank from the clean bottle and rarely from the other one. He determined that it was society and not chemical addiction that played a bigger part in the behaviors of an addict. I am not discounting the chemical hooks in drugs, yet it has been clearly and scientifically argued that societal settings determine whether someone is recreational or an addict. | 7 |
7lio8l | Other | What is the strategy behind repeating a person’s name when talking to them? I’ve recently been shopping for a car, and when talking to the car salesman, I couldn’t help but notice that he kept saying my name when talking to me. I also remember hearing this type of dialogue when watching a video of an illusionist play a trick on someone, I’m assuming they are trying to distract their brain without realizing. Is there a specific strategy to this? Or is it just how the man talks? If so, how does it work? | The name repeat is a trick to build rapport, but also in my case, since I am no longer selling anything, it is merely a memory enhancer. It is easier to remember something you have heard if you also say the words. Normally I forget someone's name in less than five seconds after being introduced, By repeating it, I can easily remember it for over ten seconds. | 4 |
k8u66q | Biology | How do certain ingredients in foods cause cancer? For example, Splenda. I know this causes cancer, but what do these things do in your body to cause the growth of a tumor of some sort? | So let me explain something about cancer studies to identify carcinogens. _Possible_ carcinogens are discovered by science using the following procedure. Rats, which always die of cancer, are exposed to large doses of these chemicals. Then, if the rats die sooner from cancer, that chemical is a possible carcinogen. Now the rub here is you know being exposed to a large dose of a chemical may cause cancer. That’s called a screening test. Very useful to know which chemicals you should be careful when handling. But getting small doses may be safe. We don’t know. Now I’m not gonna say you need not to be concerned when you here “possible carcinogen,” but it’s also not cause for alarm. Mouthwash is a contains a _known_ carcinogen. Heavy doses will kill you. Yet it’s considered safe for topical applications. “The difference between medicine and poison is dosage.” | 2 |
61g1ab | Technology | If flash drives are so cheap and fast why aren't they a good replacement for a SSD? So I've been wondering this for a while now, basically there are loads of benefits to flash drives to a solid state drive that i can think of off the top of my head, they're small and compact, portable, and most of all, very cheap compared to the counterpart. So why instead of using a SSD for you computer to store things like games and so on don't we use these helpful little sticks? Am i missing something and is there more to this than what i understand?? | A typical SSD connects directly to your computer's internals via a protocol called SATA. SATA is fast. SATA is also simple: you plug a storage device (and only a storage device, such as a hard drive, SSD, or DVD drive) into a short cable to your computer's motherboard. A flash drive connects via USB. USB is slow. It is also flexible: the USB protocol knows how to handle flash drives, keyboards and mice, wi-fi adapters, charging cables, and myriad other devices. And it is convenient: you can plug and unplug devices at will, chain cables reasonable distances, split a single port using a hub. But these features come at a substantial performance cost. When you use a typical internal SSD, you're using a specialized system designed and optimized for fast access to drives. When you use a flash drive, you're using a generalized system that can conveniently accommodate all sorts of devices. The former will almost always be faster. | 3 |
6yfp2v | Other | what happens to animals who live in the ocean beneath where a hurricane is? | They freak the geek out but in most cases they'd be fine. Closer to shore is far more dangerous. | 19 |
hkez6a | Economics | If humans manufacture currency, why can't we manufacture more money and hand it out to the less fortunate /lower class? | Without something backing it, money is just paper. Economies are massive in scale, but not infinite. Each bank note is essentially a portion of a government's wealth. Printing more money, but not generating more wealth is simply dividing that wealth further among currently circulating notes, not creating more. Hyperinflation is basically that on steroids. Eventually you get to the point that the money isn't worth the paper it's printed on. | 4 |
avl2qh | Technology | On older game consoles (NES, etc.), how is movement not bound to the shown pixels? It's difficult to put into words, but on older consoles, how is it possible that the player is able to stand, say, in between pixels? | Because the player position is stored as a number in memory. The precision of that number is greater than what the pixels can render. It calculates the nearest pixel to draw the image to given the player position. | 2 |
7lby8u | Biology | Do animals understand music? | I definitely saw some study a while ago claiming that dogs enjoy reggae- [here’s something about that]( URL_0 ) - so I assume that other animals probably have similar understandings of music. | 4 |
n4v6yb | Biology | why is yawn so communicable? Some say its a presentation of sleep ,where as some say its because of lack of oxygen can someone put more light? | Mirror neutrons probably. As you see someone yawn you experience yawning on your end and that process of you understanding their yawn makes you yawn too. E: neurons. yep. | 1 |
8blrjo | Technology | Why does "game mode" on TV and monitors look worse and other settings? | The biggest thing game mode does is turn of the chip that processes the video to make it smoother and have less noise on normal TV viewing or movies. This can have a huge response on the TV response time at the expense of, in some cases like your describing, the *smoothness* of the images. | 5 |
bt955a | Mathematics | Why is it so hard to imagine 4D objects | Because we see the world mostly in 2D. We infer 3D from context and to a minor degree by stereoscopic vision (seeing slightly different images from our two eyes lets us determine how far things are). 4D objects require us to really SEE 3D- to know what’s inside a closed box just by looking at it. To see the form of an object and not just its exterior. This is tough to wrap our minds around. Try reading FLATLAND by Edwin A. Abbott for the classic book trying to understand dimensions | 4 |
bpbsr8 | Other | How do we know, that there is no solid ground on Saturn? Hey, So Saturn had been always referred to as a "Gas giant". I always understood it the way that the plant is basically completely composed by gases and there is no solid ground below the thick layer of gases/clouds that we can observe from the far distance, or recently closer distance (like in [this]( URL_0 ) post). However, how do we actually know for sure that there is indeed no "solid ground" beneath this layer? AFAIK no probe ever managed to penetrate it and send back the data confirming this. Or Am I wrong? Is it basically just a theory, or how did scientists obtain a solid proof that there's indeed only gases beneath the upper layer of the planet? | First we can know the mass of Saturn by observing it's orbit. Basically, the mass of the Sun, the mass of Saturn, the distance between those two and the speed or the orbit are all in relation. So by knowing the mass of Earth we can calculate the mass of the Sun, with telescope and trigonometry we can measure the distance and the speed of the orbit. So that give us the mass of Saturn. & #x200B; Then against with a telescope and some trigonometry we can measure the size of Saturn, so we can calculate the volume, which together with mass give us the density. The density of Saturn is really low, so we know that it's made of a gas since no liquid or solid with a similar density can be found in large quantity in nature. & #x200B; Secondly, when light pass through matter, some of it will be absorbed. Each atoms will absorb a very specific and unique set of wavelength. It's like a finger print of the atom the light pass through. We can analyse the spectrum of the Sunlight and then compare that to the sunlight that passed through or was reflected by Saturn. We will see some black lines in the spectrum and those indicate which element is present in the atmosphere on Saturn. Those black lines won't all be the same. The more of one element there is, the more of that wavelength will be absorbed. So by looking at the spectrum we can estimate the ratio of each element. & #x200B; Thirdly, now we know what the atmosphere of Saturn is made off hydrogen and helium. Which make sense since those are the two most abundant atoms in the universe. But if Saturn was made entirely of hydrogen and helium, it would be less dense than was we calculated. That mean that even if the atmosphere is made of gas, there must be a core made of denser material. | 2 |
dqu51z | Other | how can humans distinguish melodies,harmonies, etc. in pieces of music apart from just random notes being played? | A lot of you are answering this question as if OP was asking how melodies/harmonies are constructed from the perspective of music theory (describing intervals, etc.). It is important to note that this is not the question OP is asking. The question is how *humans can distinguish* melodies/harmonies from random notes. In other words, the question is about perception and musical cognition. For instance, why is it that a particular sequence of notes is *perceived* as a melody, and another sequence is not? The question OP is asking is arguably much more interesting than the one most of you are answering. I’d love to see someone well-versed in music psychology give an ELI5 answer to this question. | 14 |
b8vt36 | Biology | Why is it okay to eat parma ham raw but not smoked bacon? I was told that you have to cook smoked bacon before consuming but you can just eat parma ham raw. | Parma ham is air dried, which is a conservation method that makes it ready for human consumption. Bacon is treated with salts, which conserve it, but still require cooking. | 3 |
7d286g | Biology | Why is it important to do stretches before exercising (i.e. pull-ups, push-ups, weightlifting, etc)? | it's actually not important at all. You'd be best just warming up, and a warm up is literally just a warm up for your muscles. And the best warm up for an activity is just to do that activity at a lower intensity. | 18 |
8alsbi | Repost | Why does hearing your own voice through a recording sound so much different than how you hear/perceive your voice when speaking in general? | Slightly different question, why does hearing your own voice through a recording always sound bad? Why isn’t anyone ever pleasantly surprised at how their recorded voice sounds instead of disgusted and horrified??? Edit: it appears some people do in fact like the way their recorded voice sounds! TIL! | 24 |
goh6hl | Economics | - With governments pouring so much money into economies right now, why is no-one talking about hyperinflation? | No, hyper inflation generally only occurs when a country is trying to print money to buy a lot of something on another currency, the Weimar Republic was trying to buy Francs, Venuzuela imports the majority of its food. That's not something we've seen happening so far. | 2 |
f0qhuk | Other | Why is it that spicy food always seems so much spicier when hot (temperature)? | I forget the actual receptor name - it’s been a while (Trpv1 from a quick google search) but we call the sensation hot because it quite literally is binding to receptors on your tongue and in your mouth that relate to sensing/ regulating temperature (and can produce pain/irritability responses etc). Eating foods that are hot in temperature (another trigger for these receptors/related thermal receptors) then is an additive effect for your overall sensation of sensing hot/increased temperature. Menthol (like menthol cigarettes) has the opposite effect that works in a similar way in that it binds to tprm8 to create a cooling effect. | 9 |
d1xulv | Economics | why is Africa so underdeveloped? | there's a really good book that goes into this, amongst why there's a "First World" and a "Third World", called Guns Germs & Steel. Some surprising reasons why the Northern Hemisphere continents are generally better off than the Southern Hemisphere continents. | 3 |
7c0mb6 | Economics | How does valuation work for tech startups? Like it says in the title, how do people decide how much a tech startup is worth? I've seen countless tech companies that seemingly produce very little but are still valued at astronomical numbers | I've worked at silicon valley startups for 10+ years and I can tell you, with my hand on my heart that the numbers for early seed rounds are basically made up. I mean, there's a *logic* at play but it's based on what you're able to raise to deliver a prototype of your vision. If you have an idea for "umbrella drones" you spec out your engineering cost to build the devices and a fabrication facility, then you need to hire people so you cost out those salaries, you need office space and marketing etc and you arrive at a number. Call it $2mn. Then you start meeting investors, you give them your pitch which will go something like "there's 3bn people affected by rain every year, and 1.8bn buy umbrellas every year, which creates an umbrella market worth $4tn / year. We believe we can produce and sell 120k $1000 drone umbrellas / year at a market cap of $120mn, we're looking to raise $2mn in return for 5% as a series A" etc etc (i'm being flippant, but you get the idea). Investors want to give the least amount of money for the most return at the lowest risk, so they tend to partner up with other Angels or VC companies. So 1 investor might give $100k and someone else might give $500k, but each of those transactions will establish a value based solely on the cost of producing the initial idea (and frequently, just a prototype version of the idea) and the founders ability to sell his pitch. Investors also like to call the shots, so while the founder wants to execute his vision, he still has to go and report back to the VCs on progress (usually via board meetings), if the company is not growing fast enough, or the VCs have started seeing trends in other sectors that will yield a safer return, they can and frequently do, make strategy changes they expect the company to embrace. The founder is free to ignore the request, but he won't get another round of investment from that investor. Profit is rarely a factor in the equation. Everyone *wants* a profitable company but companies can operate solely by raising cash, and they raise cash by talking about their appeal and using metrics that verify their appeal, ie how many users, 40% year on year growth, subscriber penetration, repeat visits, unique impressions etc. It's why twitter, a company that makes almost no money, is worth $7bn. It's madness when you think about it. Once that initial investment is raised, a public valuation now exists and all subsequent valuations are essentially an evolution of it. | 4 |
m9x55k | Technology | Do Ancestry tests like 23andMe misrepresent what genetics is able to objectively say about a person? | Could you be more specific? They are private companies with a sales pitch, so you have to do your own due diligence. They both find relatives who are third cousins and closer pretty easily. Both try to assign nationalities. Those results can be a bit fuzzy. They aren’t bad when the percentage is at least an 1/8. I wouldn’t trust anything under 2%. That’s just noise. 23andMe adds whether or not you have certain markers associated with health risks. I’d ask a doctor how important or accurate this information is. | 4 |
a7v8rf | Biology | How come my 4y old remembers last years christmas very well. And remembers everything we did last summer. And I don’t remember anything from my first 4 years? Can’t be the years cause a 60y old remembers his high school pretty well. | There's a point at which you start forgetting things from your childhood. It happens after the four-year mark. It's not like a four year old has no memories at all, they'll just forget them later. | 3 |
m2jnyy | Other | . Why does 70 degree (Fahrenheit) air feel warm but a 70 degree shower feel cool? Why does 70-80 degree feel warm, but 70-80 degree water feel cool? | Air is a very poor thermal conductor. Heat doesn't easily move from the air into your body or vice versa. Water on the other hand is very good at conducting heat. So water that is substantially colder than your body temperature will pull heat from your body. This transfer of body warmth to an object is the sensation we feel as "cold". As a side note, sweat takes advantage of this because air is so poor at conducting heat but water will pull excess heat from your body and evaporate more easily to cool you down after exertion. Without sweat or other means of cooling humans would overheat from moderate exertion. | 3 |
81y6vq | Biology | Why do primates such as gorillas, baboons, and chimps (especially those in a zoo) retain so much muscle and strength doing little to no muscle building activities. Yet, humans must consistently work out properly to retain muscle and strength? | Myostatin. Myostatin is a hormone that (statin) stops muscle (myo) growth. Humans produce a large amount of myostatin, whereas most animals don't. Cattle can be selectively bred to have myostatin deficiency, and then produce more muscle mass relative to effort. Why? Probably for reasons such as dexterity and fine motor control. Our motor units do not all fire simultaneously, which lowers our relative strength but leads us to have more refined movements. | 17 |
dl6yhn | Physics | How does atomic bombing leave permanent shadows? | It does not leave permanent shadows, per se. Nuclear weapons have such a large blast radius that the different parts of the explosion separate. The first wave to hit is the heat wave, which is all of the light from the blast cooking anything it touches nearby. The result is that areas where the light cannot reach will not get cooked, and if the entire area does not burn down, this uncooked area is visible. | 3 |
62e856 | Other | Why did contact with the Vikings not have the same effect on Native American population that contact with Europeans at a later date did? After contact with Columbus and Europeans in the 14-1600's Native Americans lost massive amounts of people due to exposure to diseases they had no natural resistance to. Why wasn't there a similar effect when the European Vikings came to love settle in in North America. Wouldn't they have brought similar diseases with them? Wouldn't they have caused a similar effect? EDIT. It seems like it comes to the point that Viking society wasn't dense enough to produce the plagues that the later settlers brought. I never would have thought about that. Thank you guys so much!! | They very well could have spread disease. I know one very early account of the new world includes seeing smoke pillars dotting the shore as far as the eye could see from miles out from said shore. Before the classical Thanksgiving/Puritan settlement there were numerous prosperous tribes. I think Squanto may have been a "survivor" of one. My history is a bit rusty. Keep in mind that Native American/Vikings were not much for written history and also if "History is written by the victors" a lot of history has been erased. | 17 |
g9n3fy | Engineering | How are bridges tested for how much weight they can hold without breaking the bridge? | disregard all other answers, the true answer is & #x200B; they make the bridge so fuckin big that they know it cant possibly break with a sensible number of cars on it | 4 |
68hzh8 | Other | Howcome anxiety and depression are so common? Is it something to do with society and lifestyles or how children are raised? Or is it simply because it's more acceptable to talk about it which means it's more easily diagnosed? | There is not a direct answer to this. I will put some factors: * Impossible to archive standards: I think this is the biggest. Instagram accounts with beautiful people 24/7. Those people are posing for the photos and they have all arranged to look perfect. Still it gives us the impression that that's how they live and "OH I WANT TO BE LIKE THAT". That creates a fear of under-archiving. The "Fear of missing-out". Anxiety. * Massive Social networks. This is the source of anxiety. Everyone is exposed at all times on FB, IG, etc. (you can choose to dont join/quit, But let's be honest: Any person from 16-23 that does not have a FB account does not exist...) This create a need to be accepted in society. "Oh, I want 1000 likes". Major anxiety source. Also bullying * Global economic crisis made everything harder: College, New clothes / technologies, families, payments, savings, vacations, getting jobs, travelling... Leading to frustration and depressions specially in adults. There are a lot of answer for that question. I think I've talked about some majors | 3 |
b16u37 | Other | How do hotels decide what rooms to put guests in? I have never understood how hotels decide guest placement in rooms. I feel like I'm always so far from the elevator or right next to another guest when the hotel is empty. Is there logic behind it? Is it random? Am I overthinking the process? | How do you request a bigger room? “I’d like a nicer room for free, please?” | 3 |
5pl4gz | Physics | Why does ice on tile flooring melt substantially faster versus being on carpet? Have a four legged buddy who loves to eat ice cubes and leaves them laying around sometimes. My kitchen has tile and the ice melts within minutes. Other times he leaves them on the carpet. I've picked some up after at least 2 hours and it seems minimally smaller. I'm sure it has a big thing to due with surface contact but why such a big difference? | Ceramic tile has a much higher thermal conductivity than carpet. This allows heat from the tile to transfer more quickly to the ice, and thus melt it faster. Carpet is essentially an insulator by comparison. If you're wondering about the relative thermal conductivity of other surfaces, then just touch them. The cooler they feel, the higher their thermal conduction. | 2 |
8m689i | Biology | Is intelligence hereditary? | The maximum IQ of a person is mostly determined by genes. However, many things can lower a person's IQ and a few things, beyond healthy diet and exercise, may even increase IQ. Height is often compared to IQ and is a mostly effective comparison, both are very heritable compared to other personal characteristics. IQ is the broadest form of intelligence that can be reliably measured. It can be thought of as the average speed that a person learns a variety of different things. It is widely recognized that there are other forms of intelligence. These other forms are harder to measure, and heritability is therefore hard to determine. However, IQ is so highly heritable that other forms of intelligence are likely less heritable. | 3 |
61lg7s | Biology | What are the medical effects of THC vs CBD in marijuana? | CBD is non-psychoactive, anti-inflammatory, anti-anxiety, neuroprotective and in many cases anti-tumor. It won't make you feel 'high' in the traditional sense, but it make many people, myself included, calm. THC is psychoactive. It is what gives the intoxicating effect that recreational users are after. When it converts to THCA in the body is provides relaxation and pain relief effects. Pure THC is generally unpleasant, and can lead to psychosis in extreme cases. THC and CBD in balance produce elevating experiences. If you are too high from consuming too much THC, you can ingest CBD and the effects of THC will be diminished. | 1 |
bekwdt | Biology | How are 'waves' created? I see people with curly short hair put on a durag and a few hours later they take it off and it creates this wave pattern. How on earth does that work? | It works because the hair is naturally curly. Just putting on a Du-Rag or Wavecap doesn't necessarily work. When you see a black guy constantly brushing his hair, he is trying to get waves. This is because the hair is naturally coiled. Brushing the hair consistently straightens and lengthens this coiled hair. But not completely straight. It's slightly curved. This curving motion creates a wave-like pattern. The wavecap is put on to keep the hair laid down. and to prevent it from coiling back up. After doing this for a long enough time, the hair is "trained" to grow like this. | 1 |
gn03de | Technology | How much more powerful are movie industry standard computers used for CGI, than a $3000 home gaming PC? Is there a limit to how much processing they can do? | The final version is rendered on hundreds of computers networked together in a render farm. While working on the CG they use a lower quality version of their assests they can work with in real time. Sometimes it's very real time. There's a video from Infinity War showing an overlay of Thanos face over the actor so they could see a lower quality image of how the CG face will look. The Mandalorian uses a partial CG set where they have the rendered image displayed on giant screens on set. This allows everybody to see what the CG environment look like, and lights the physical set properly at the same time. Render time is measured in hours per frame, but they can work on multiple scenes at the same time. If you look at the credits after a Marvel movie you'll see a lot of visual effects studios work on the movies. | 2 |
cjn8ne | Biology | Can a body that currently needs 7-8 hrs of sleep get used to 6hrs of regular sleep? | Used to: yes. Work as well as with it's required amount of sleep: no. At day time, your brain has to sort through a lot of new impressions and experiences and stores all that. When you sleep, your brain does maintenance work to sort through all this and to decide what to keep and what to toss. Some brains have a lot of maintenance workers who also work really fast, someone else's also work fast, but there are less. And then there are brains where much more time is needed to clean up. The fastest maintenance workers have their task completed in four hours. Those are very rare. The majority of brains have the workers sweep through all the alleys and corners in about eight hours. And some even need nine to ten to complete their task. When the owner of that brain is still growing, there is more to sort through from the day, and the maintenance is less experienced, so it might take even longer than that and over age, they might need less time. So your best amount of sleep varies over age. If you get less than that amount of sleep, the stuff just piles on and on and the workers cannot finish their job. The next day, you might feel groggy, this is because there is still stuff not collected in the streets and your daytime workers need to climb around that stuff. You will also notice that the workers did not have time to store away all your newly learned information, and this is why you are more forgetful. You can find out the natural amount of time your brain's cleaning force needs by going to bed when tired, sleeping and waking up without an alarm clock over a few days. Your workers also work in shifts, called REM phases. Those phases last about 90 minutes and your body wakes up easiest between shifts. So if you often feel tired, you might be waking up inmidst of an ongoing shift. If your brain cannot concentrate solely on being cleaned, because for example, there is noise going on or light shining into your room, the workers become less efficient even interrupt their shifts, all leading to being more tired. You cannot train your workers to "be more" or faster. You just have to work with what you've got, but understanding the work that is being done and how your body does it can help you feeling more refreshed in the same amount of time. | 3 |
9qz3t6 | Technology | How does a suppressor work on a gun? | There are 3 sounds to a firearm: -movement of the action as the firearm cycles -sonic boom (subsonic ammunition does not have this) -gasses escaping the barrel Suppressors reduce the noise of a firearm by using baffles to slow down the gasses that way they produce less noise when they start escaping the barrel. Please note that supressed guns, even with subsonic ammunition and all the tricks in the book to improve how effective the suppressor works, the firearm will still have a loud, identifiable report, but now it is closer to a loud paintball marker. | 12 |
g2umr9 | Biology | Why don’t plants get dusty? We have a lot of plants in our home and realize none of them ever accumulate dust. Meanwhile, our fake plant does. Is there some sort of biological process that prevents dust from collecting on plants? | I’m pretty sure that even real indoor plants do accumulate some dust; at least mine do - although they don’t accumulate it as much as other surfaces. The plastic or fabric leaves on fake plants may have a surface that attracts or retains dust, due to stickiness or static electricity. Also, real plants do move slightly on their own, to follow the sun - either daily or seasonally. This slight movement might be enough to reduce the amount of dust that accumulates. | 1 |
7uu3h8 | Other | - What led to the early to mid '00s shift away from beige as the standard colour for the computer. | I was assuming you meant the colorful iMacs not the later all black machines. Throughout the 90s supply chain management software radically changed what could efficiently be manufactured. This led to a much broader array of colors in manufactured items including computers. Apple’s wild colors was all about being able to efficiently sell a big ticket item in multiple colors. They weren’t always successful and had to force some colors on retailers. Their foray into aluminum was also driven by tech efficiency, there’s a great video out there about how the various computers pieces are all cut from single aluminum blocks with minimal waste, driven by 3D modeling and manufacturing software. Apple has lead the way most likely because they get away with charging a premium to cover their experimentation. Even if you’re not a fan of their pricey machines, they’ve had a radical influence on industrial manufacturing that’s interesting in its own right. | 2 |
7q5krh | Economics | What is the GDP Even with all the research online, I can’t warp my head around what the GDP really is. | GDP is gross domestic product, a measurement of the total value of goods and services produced by a country in a given year. Every t-shirt, car, Apple, candlestick, massage, medical treatment... Every thing people in a country buy or service people pay for. This measures roughly the economic output generated by that country over the course of time. It's one of many measurements used to reflect what is going on in an economy. More useful is GDP per capita, which is simply the GDP divided by the number if people living in the country. So a country with a high GDP but also a high population such as China would have a lower GDP/cap than the United States which has a higher GDP and a lower population. | 3 |
d6nwlb | Biology | Why exactly do we age? Can it be slowed down systemically? | New episode of the joe Rogan podcast with David Sinclair talks a lot about aging and genetics and stuff. Maybe check it out? | 2 |
74zk2j | Biology | How did we find out our brain was the thinking organ? | A likely explanation is effects of physical damages. If you get hit in another part you might bleed and die or if you survived have local problem in that part. Damages to the head might resulting changed behavior or other easy observed thinking problem. So when head damages result in that kind of damages it is not hard to guess that you think with that part. The explikation is also a part of how we know what different parts of the brain does. A damage to the same part can often have the samma effect in different people so that have been used to identify function. | 2 |
5qcygn | Economics | How does taxing Mexican imports 20% to build a border wall not just pass the costs on to American consumers? | You need to consider what the imports are and whether there is an alternate source. From the US govt trade site we get the top export categories from Mexico. The top export categories (2-digit HS) in 2015 were: machinery ($42 billion), electrical machinery ($41 billion), vehicles ($22 billion), mineral fuels ($19 billion), and plastics ($17 billion). Now interestingly, Mexico doesn't make a lot of this stuff internally. What happens is foreign manufacturers use Mexico as a cheap landing ground for NAFTA. So what would happen if we taxed mexican imports 20% ? Without a full analysis of the total cost models it's tough to say. We can make a reasonable guess that the total value of exports would begin to drop off a cliff as customers looked to alternate sources, or suppliers re-routed their operations probably through Canada or possibly direct to the US. This would have a small impact on us but a devastating one on Mexico, meaning it's a very effective threat. | 7 |
6dskxu | Mathematics | Gambler's Fallacy. After a fair coin is tossed & lands on "heads" 500 times the chances of it landing heads again are 50/50. In older post asking the same question someone explained it like this: "The fallacy lies in being confused about when you should start counting." That as independent events the chances are 50/50. But they're not independent events when you are you're taking into account the staggering unlikeliness of a fair coin landing on same side 500 times... The chances of a coin landing on heads AGAIN in that series isn't 50/50, is it? Because that seems to be what ppl argue with this... If so I can't wrap my head around it. I'm 5!! | People love the gambler's fallacy because they like melting people's minds. But it's not so simple. When people ask "what's the chance of flipping 99 times, getting heads 99, times, then getting heads again on the 100th flip?" They're asking two questions at once. 1. On this next flip, what is the chance of me getting heads? 2. What is the chance of me getting heads 100 times in a row? The answer to the first question is 50%. Coin don't know about your other coin flips, coin don't care. The answer to the second question is 1 / 2^100. That's how unlikely it is to get any one specific sequence of coin flips. It's the combination of 100 50% chances. The fallacy comes from people thinking those two questions are the same question. | 11 |
ip5uvz | Biology | how is the brain able to give us images when we are imagining something? | So someone asked this same question about 5 years back. There was a pretty good explanation there from u/michaelhyphenpaul that I'm going to paste below. Something to note would be that 5 years is quite a long time for a field like neuroscience where we're learning more almost every day, but nothing about their answer seems off to me. Anyways, here it is! > Going for an explanation a 5 year old might really get: Part of your brain (the back part) controls vision. When you see a real banana, that part of your brain responds to the light coming into your eyes, and it tells the rest of your brain about what the banana looks like. It says things like "it's yellow," "it's curved," and "it has a brown spot right in the middle." > When you imagine something, the visual part of your brain isn't responding to the light coming into your eyes. Instead, it's responding to what you're thinking about. You remember what a banana looks like, so you can imagine it. The same kind of messages are being sent by the visual part of the brain to other parts (yellow, curved, brown spot). But when you're imagining, the messages are less clear then when you really SEE a banana. That's why "it's there, but it isn't there." > But, this is really a good thing. Think about this: what would happen if you COULD really see something when you imagined it? Every time you imagined a tiger, you'd see a tiger appear in the room! That would be bad; you'd probably run around screaming and being scared a lot. So your brain has evolved a way to let you imagine things without being confused whether or not you're really seeing them. > OK, bonus ELI-25 time: There's a really cool study that came out recently, which looked at exactly this question. They used functional MRI to examine how responses in the visual cortex differ when people saw a set of 5 familiar paintings, versus when they imagined them. They found similar (but for the sake of simplicity, messier) response patterns during imagery versus perception, even in the lowest levels of visual cortex, suggesting that imagining a picture activates these parts of the brain in a similar way to actually seeing it. > Here's a link to the paper: URL_0 > In the interest of full disclosure, I'm friends and colleagues with some of the authors, and I was around when they were working on this project (was finishing my PhD in neuroscience at the time), though I wasn't directly involved in their work. | 11 |
8kmtou | Technology | How did Google manage to get 3d models of every building on Google earth? | The footprint is taken from the satellite \(or top down image\) or map. The height can be calculated by referencing the building from different vantage points, this can be from multiple plane positions or even the street view images. Another method is to analyse the shadow length against the time of day. Some are produced by hand \(google used users to contribute to their model collection\). Some are provided by the building owners, if you want your building to be found, the more information you give google on it the better. Some are taken from public data such as planning documents. IMany new buildings are planned using the principles and technology of "BIM", which would submit the model shell to the planning boards. | 10 |
e7dshx | Physics | how does the shape of an airplane's wings generate lift? And how does the retractable wing flaps affect that? | The shape of the wing when viewed from the side is called an aerofoil. As the aerofoil moves, the wind / air splits into 2 streams. The air passing above the aerofoil generates higher velocity (speed in simpler terms). Whereas the air velocity below the wing is low. Without going into the intricate details of fluid dynamics, higher velocity creates a low pressure and vice versa. Since the pressure below the wing is higher (due to the lower air velocity) it generates lift, hence enabling the aircraft to be airborne. A similar concept is applied to the rear spoiler of a car (the opposite) to create downforce. | 1 |
aemfe5 | Technology | How does a helicopter fly forward, and not just up/down? | In order to fly forward, a helicopter will tilt slightly forward. Now that it is tilted forward some of the downward thrust will actually push it forward instead of just up. | 3 |
8vtghl | Biology | Why do stairs always exhaust me so easily if I’m in pretty good shape? | i used to do the stairmaster at highest setting for 45 mins a day 5x a week. Fat fucking fell off. I was 6'5" 250 12% bfat and the 5 flights I had to take at work STILL made me breath heavy once I got to the top. | 17 |
9lsmlu | Other | What caused the deserts across the Sahara, Middle East, and Central Asia? What weather conditions created [this]( URL_0 )? Or did ancient civs have access to nukes? All I've heard for central asia is that the Himalayas block moisture from the Indian Ocean leading to a rainshadow effect. Edit: I still think this is the result of the Finno-Korean Hyperwar | I wish we could keep this near the top because I have two follow on questions related. 1. Could the amount of sands in the deserts be contributing to global warming similar to the asphalts in our streets? I mean if you go to a patch of grass on a hot summer day - the soil and grass is cool to the bottom of your feet. But if you walk on hot cement sidewalk or asphalt driveway it literally burns your feet at high noon - that absorption of heat has got to be contributing to global warming. And I never thought of it until I saw this picture today URL_0 - I was always thinking the sands acted as a mirror similar to ice and reflected the sun's heat energy - but sand is not a reflector of heat - it's an absorber - it you walk on stagnant *dry* sand barefooted - you can burn your feet - so the sands of the sahara are not reflecting that heat energy - they are absorbing it. ((Not saying human's pollution and greenhouse gases are not contributing to global warming)) - certainly they are the main factor. But I wonder if the sands (and cement roads/streets etc) that cover *(random estimate here) maybe 15% of earth's land mass might also be contributing to global warming. Someone mentioned above that planting trees that could live in the desert would be expensive and difficult - but I am now wondering if it might have a huge impact on the environment world wide? | 14 |
80y35k | Biology | What is the reason that animals such as humans and orangutans kiss their kids? | I’ve always heard that it’s most likely antibody and bacteria sharing. Kind of a rudimentary vaccine. Hey here are the things I’ve been exposed to, I give them to you so your immune system can fight them and you don’t get sick. | 3 |
ckcnnv | Technology | Why do airplane passengers need to turn off cellphones or electronic devices while a plane takes off/lands? | Its nonsense. Its based on old avionics devices that could have radio interference , afyer that it was because "holy shiit you never know". but today's technology has changed the game. Did years ago. | 6 |
e3gwxz | Technology | How did old school shooter gun games like duck hunt or arcade shooters accurately track your shots with only the gun and without a sensor bar or camera? | Back then, the screens used a different technology, they mostly only lit one pixel at a time (pixels kinda faded away after being lit, but quickly faded away from the brightest they got), the image looked whole to the human eye due to persistence of vision, but with [high speed cameras]( URL_1 ) you can kinda see how it works. The way games like Duck Hunt worked, is the moment the trigger is pressed, the game first draws a fully black screen to get a base level of light (to deal with environment light and such), and then it would paint white only the area where the target was; it would then check if the light sensor on the tip of the gun picked white or not (it was basically like a single-pixel camera with strong zoom), at the exact moments where the white parts of the screen were being lit up to detect a hit (if there were multiple targets present, it would light up each target in order to identify which of them was hit). | Those games have a hard time working on modern screens because with modern screens the consoles no longer control individual pixels directly, they send the whole picture and the screen displays the frame when it feels like it; so the precise timing trick can't be trusted anymore. edit: Someone else posted [this video]( URL_0 ) on a reply to another comment here that illustrates how the tech works. | 18 |
f74668 | Biology | How do rape kits/paternity tests work if sperm only has 50% of the father's DNA? | I mean...spermatozoa contains 50% of DNA compared to the othet cells. But 100% of this 50% DNA belong to the guy who ejaculated. | 2 |
m7hf77 | Biology | Why is waking up earlier than usual so difficult no matter what time you fall asleep? | Your body has an internal clock that it keeps sync’d through a combination of routine and sunlight/darkness cycles. Thus your body “knows” what time it is, and attempts to keep to a rough schedule by getting tired and waking up around the same time each day, based on when you’ve been going to sleep and waking up most recently. When you wake up is thus a combination of both how much rest you have gotten and also what time you have been waking up for the last several days/weeks/months. It is easiest to wake up when you fulfill both of these triggers and get adequate rest during the regularly scheduled sleep period. It is hardest to wake up when you aren’t hitting both of these targets. So trying to wake up early with inadequate sleep is very difficult. Trying to wake up early after going to bed earlier is better, because you are getting adequate sleep, but still harder than if you were keeping to your regular sleep schedule. | 1 |
k227u9 | Chemistry | If rice have arsenic (a kind of toxic elements) and can cause health problems and increase risk of chronic diseases, then why Asian people who consuming rice every single day have no problem whatsoever? | Rice is prone to contamination by arsenic etc. because of the way it's grown (in flooded conditions with low oxygen). If the water is contaminated the rice will be too. But most of the arsenic sits in parts of the plant that aren't eaten. Arsenic is found in groundwater all over the world, and in places where its levels are high enough to cause problems, people *do* have symptoms. If you get your rice from places with highly arsenic-contaminated water you might have issues, but most countries can (and do) grow their own rice. | 4 |
8gaf48 | Physics | What is the TeV mass scale and what does it have to do with particles beyond the standard model? Title is self-explanatory. I'm researching this PDF: URL_0 for an assignment. | Ohh thats my paper! Its a rather old one of course, our latest version is [here]( URL_0 ) with a preliminary result [here]( URL_1 ). Anyways I feel honour bound to do an ELI5 of it now! Will do my best although its very late in Geneve so appologies if its not clear First, what do we mean by a scale? A scale refers to a rough “order of magnitude” and the physics happening depends on this scale. For example you can completely ignore relatively at the speeds we encounter in our daily life, these are "non relativistic scales". So at a given "scale", different physics processes become important. And particle physicists like to measure everything in terms of eV (and I do mean everything!), when an eV is an electron volt and is the energy an electron will gain when it passes though a potential of one volt. Through the magic of E= mc2, this relates to masses. A proton weighs 1 million electron volts (GeV) while the heaviest known particles way ~125 (the Higgs) and 174 GeV. A TeV would be 1000 GeV. So physicists have this great model which describes almost all known physics, this is known as the standard model. And its got a bunch of particles. There are the eV scale particles (neutrinos), the MeV scale particles (electrons, muons, light quarks), GeV scale particles (protons, taus) and a bunch of 100 GeV scale particles (Higgs, W, Z bosons, top quark). And thats as far as the previous colliders could really go. Energy is conserved so to make a TeV particle, you have to put a TeV in, previous colliders just didnt have the omph. So for this paper, we had a shiny new toy, the LHC which can go up to 7 TeV (although not all the energy you put in can be used). That paper was in 2011 when the LHC was brand spanking new, simply we were exploring a region we had never seen before so we were seeing if there were any lovely new particles to find there. Exploring the unknown to see what is out there! Turns out there was nothing there but it was a reasonable assumption if you’ve seen new particle every time you increase your energy by a factor 10 in the past, you might see a new particle going from around 100 GeV to around 1 TeV. But we havent given up and we’re still looking for them to this [day]( URL_1 ), we have lots more data on the way! And why did we hope there were new particles there even though our standard model didnt predict any, well thats a story for another time... | 3 |
5qnxq9 | Physics | Why are things wrapped in aluminium foil to keep them warm but never cool? From my understanding, aluminium foil reflects both light and heat. I've seen things wrapped in foil in order to lock heat in (e.g. jacket potatoes) but I never see things wrapped in foil to keep them cool. Is it possible? | In high school I used to wrap my soda cans in foil for my lunch. Pretty sure that did nothing. | 4 |
73wuk9 | Biology | Why can't people who have had cancer in the past donate blood? Edit: well this blew up overnight. Thanks for the informative answers everyone. My mother kicked breast cancers ass the second time just over a year ago and was told she could not donate blood ever again. It had spread to get lymph nodes so maybe that's why? From the responses I gather that unless it's a cancer of the blood you're allowed to donate after 1-5 years clear. | Wait. So if you transfuse the blood of a cancer patient to someone healthy, you can give them cancer? Like a virus? | 18 |
8yehst | Engineering | why is it that sometimes some electric windmills are not spinning despite facing the same direction as windmills that are spinning? | It takes a fair bit of oompf to get them going. Some have starter motors, but if the wind is just a bit slower for that one than others, it may not kick in. Also, they can have brakes put on so they're not spinning during maintenance. | 2 |
blvkn0 | Biology | If fruits exist to entice animals to eat them (and thereby spread the seeds), did fruit develop in response to the existence of animals? Or did fruit exist prior to animals (and if so, why)? | Fruit came after animals. When dinosaurs started walking the earth there was no grass or trees evolved yet. We think of plants as being evolved first, but modern plants are fairly new | 2 |
9aod7k | Biology | Why is anxiety so common right now? | Social media! Everyone is comparing their lives to people with “immaculate” lives. Also porn, In my opinion, porn is a problem of the new age that other ages have never had to deal with and in 20-30 years we’ll know that porn addiction is the same as drug addiction | 21 |
e3amzq | Mathematics | Why every number to the power of 0 is equal to 1? I'm too dumb to get it | I'll expand on what I said before, since it was not enough information. (And hope this doesn't count as trying to outsmart the moderators) & #x200B; Your question is not entirely accurate - not every number to the power of 0 is equal to 1. 0 itself raises a special case. Let us start with two basic statements: x^(0) = 1 0^(x) = 0 So, if we put 10 in to there, 10^(0) = 1, and 0^(10) = 0. What if we put zero in? 0^(0) = 1, and 0^(0) = 0. This is impossible, and as such 0^(0) is undefined. & #x200B; For the non-zero cases, the other people here have given a better explanation than I could, just be careful of that one case where it all falls apart. | 20 |
gg4e7d | Physics | The idea that travelling at the speed of lìght makes one age at a different rate to those of their home planet. I need someone to make sense of it for me. I appreciate the clock scenario where it stays at 12 o'clock if you move away from it at the speed of lìght, but regardless of how fast someone travels, their body will still age just as fast as anyone else (roughly). I don't understand how just putting distance between someone's self and the rest of Earth would somehow make them age at a slower rate? You're aging, just further away.. Hope this makes sense! | The time dilation of special relativity is not an optical result of light taking longer to catch up. It is an objective fact - if I move relative to you near the speed of light, time will in actual fact be moving slower for me. This has been experimentally confirmed with extremely accurate clocks. There is an additional observational factor that has to do with light's finite speed of travel, but as you suspect that doesn't affect how much time passes for us, it just affects how we see something. If you take all the light you see and put it through the calculations to correct for the mere finite speed effects, you will still see time dilation happening. | 4 |
hek5bl | Physics | How do scientists know the Big Bang happened? What proof is there that the Big Bang happened? How do they formulate that theory with what is observable with the human eye? | We can literally see it. Or more specifically, a moment in time very shortly after it. Because light travels at a fixed speed, the further away you look, the further back in time you looking. Our sun is eight light-minutes away, so when you see it in the sky you are basically seeing an eight minute old video of it. Same thing with a star five light-years away being basically a five-year old video of that star. Look about 14.5 billion light years out in any direction, take into account the expansion of the universe and how it stretches light, and you can see an incredibly hot, dense explosion that was at one point everywhere in the universe. That explosion is made of one-visible light stretched into the microwave band, and it is essentially a baby picture of the universe. | 5 |
ak2pj1 | Chemistry | How do carbohydrates (excluding sugars) affect your insulin levels? Is a gram of non-sugar carbohydrates the same as a gram of sugar on the body? | “Sugar” is a bit of a vague term here. What we think of as “sugar” is sucrose, a.k.a. table sugar. Sucrose is one molecule of glucose attached to one molecule of fructose. Most “sweet” things are heavier in fructose, e.g. fruits, corn syrup etc. most carbohydrates that are not sweet to the taste are predominantly made of starches that break down into glucose, e.g. rice, potatoes. Exactly how it affects insulin levels, I’m not entirely sure. But I do know that fructose is not generally well accessible to your muscles and other tissues for energy. It needs to be converted to glycogen in the liver prior to being useful to a significant degree. So, as I understand it, if you consume sugar, your digestive process would break apart the glucose and fructose, sending your glucose out to your tissues as glycogen almost immediately and sending most of the fructose to the liver. Meanwhile, a starchy carbohydrate would be broken down quickly into glucose and would likely create a higher blood sugar level. As a result, my guess would be that pure glucose would have a more significant effect on insulin than sugar would. After all, an oral glucose tolerance test is given with a glucose rich drink that is, by all accounts, horrid. If fructose didn’t differ from glucose in usage, they’d just give you a coke. Chronic fructose over-absorption in the liver can cause some negative consequences. It can cause the build up of fat around the liver which causes similar health consequences to alcoholism. Research Non Alcoholics Fatty Liver Disease for more info. Last thought: the general digestibility probably matters a lot too. It’s probably much easier to break apart a simple sugar in the form of a sweetener than it is when it’s in a more complex substrate like a potato, which has amino acids and fiber that will likely take more processing to get out pure glucose. This probably affects the timing of the insulin spike. And the total glucose load will cause a proportional insulin secretion, so the absolute peak is only one metric, while the total amount secreted is another. Hope I made some sense. You’re sharp for 5! :-p TLDR: what we think of as “sugar” is a specific chemical and differs from starches that are also sugars. Yes, table sugar is different in physiological impact than other carbohydrates. | 3 |
ckybpq | Biology | - What is it that makes people contract every muscle and scream really loud when they get scared. | Instincts. Some, if not most, animals make loud noises to intimidate/scare their enemies away. Muscles contracting would store up potential energy for fight or flight. Contraction of some muscles act to make animals look bigger (eg cat arching their back or birds fluffing their feathers), this acts to intimidate the enemy as well. | 1 |
jvgy48 | Biology | Why does there have to be a plecebo/control group in a drug test? | Because what would you compare the results against? If X number of people survived after taking the drug, how would you know how that compared to the number of people that survived without drugs. | 2 |
5wn9s6 | Biology | Why is heroin and meth so addicting? I find the subject of addiction so fascinating, like why would someone destroy their lives for a gram or two of these substances? | I agree a lot with /u/femmejean . While chemical dependence can be hard to overcome it isn't the hardest part. One of the worst drugs when it comes to dependence is alcohol and that one is legal (quitting alcohol can kill you). The hardest thing about 'curing' addiction is to make it so that the addict doesn't crave the drug so much. The way to do that is to make him happy without the drug - fix his relationships, mental and physical health, living conditions, etc... The reason people crave that gram or two of substance is they feel bad. Maybe they tried it once out of curiosity but kept using because it felt nice. Then shit just keeps piling up and they just need to relax and have fun once in a while - what better way to relax than to have a bit of your favourite drug? As time goes on you find it hard to enjoy anything else but your drug and even that is loosing it's magic so you up the dose - you're already addicted for some time at that point. So, while to you it looks like they are destroying their lives to them it feels like they are holding on to the last straw of positivity. Now, whats special about meth and heroin? They are easy to get into (no heavy halucinations or side effects) and seem actually harmless when you try them. Most people describe it as just feeling nice (heroin) or energized (meth). Only when they are already addicted and are upping dosages you start seeing all the side effects. | 7 |
ns5wqv | Other | how are there more than 2 genders? I just don't get that. There's male, female and... what? Please explain | So this is gonna get deleted by mods I bet, but here goes: The concept is that gender is a social construct separate from physical sex (although there are also people proposing that physical/genetic sex are artificial social constructs too. Basically, because the male/female genders are ideas created by people, its possible for people to create more than just the two to cover different social positions/feelings/concepts. | 5 |
5va6ep | Economics | If a store buys something for $1 and sells it for $10 and it gets stolen, do they say they lost $1 or $10? | I deal with the couriers at my work who deliver our products to our customers. They frequently lose our packages (so much so I'm looking in to other couriers to take our business to). I have to send a proof of purchase to show how much we bought it for, not how much we charge the customer. What makes it worse is we have to pay for it to be redelivered also. That company really sucks. | 17 |
7d286g | Biology | Why is it important to do stretches before exercising (i.e. pull-ups, push-ups, weightlifting, etc)? | I will give you a simple answer: stretching before work-out is not a good idea as it creates micro-tears in your muscle and compromises performance when doing heavy duty lifting. Here is when stretching is actually beneficial: long-term. Stretching will allow blood to flow into your damaged muscle and allow more better development and flexibility long-term. Stretching essentially changes the way your pain-receptor picks up signals when muscle is elongated. Your muscle does not get longer. | 18 |
5w3t59 | Other | Why does smoking marijuana allegedly not contribute to lung cancer? I read somewhere that smoking marijuana does not contribute to lung cancer. Why? | Read somewhere else from here on out. Inhaling burned plant particles, no matter the source, releases bad things that contribute to the likelihood of you getting cancer. Same with any other pollutant. | 6 |
idkngp | Economics | Why are store prices sometimes listed as fractions ("3/$5" or "4/$2") or "buy X, get Y free", instead of just being mathematically straightforward? Is there some psychology behind it? I've always wondered this. I don't even know who to ask, and Google turned up nothing. When I'm shopping and I have to do some mental math to figure out the real price of buying one, two, etc. of something, why is it that stores do this in the first place? Why advertise something like 2 for $7? Why not just $3.50? Please ELI5 because it just doesn't click with me. The math isn't hard, but it seems like an unnecessary layer of complexity when it comes to shopping, like if I want 2 of something advertised as 3/$5, or if I want 3 of something that is Buy One, Get Free. And I noticed stores will say that something is "buy one, get one free" but they jack the price up from the previous week that it wasn't on sale. That happens a lot with Cheez-Its. | Stores essentially have to use these sort of tactics in order to remain competitive. Awhile back JCPenny did away with these tricks with a campaign about being honest with the consumer (no having things "on sale" perpetually, no having products be $19.99 instead of $20.00, etc etc) and this complete screwed them over. Look up the "JCPenny Effect" Another reason for pricing things as described in your title is that it creates mental fatigue that will drain your mental resources and get you to make more impulsive purchases the longer you shop for. This is why you should *always* have a list when you go shopping, only go shopping on a full stomach (when buying food), and *only* get what is on your shopping list. | 3 |
mix7tb | Biology | Why are people able to eat/drink gold leaf and not get metal poisoning from it? It’s fairly common for gold leaf to be added to alcohol or desserts to make them appear more luxurious. Why is it possible to get lead or mercury poisoning just from skin contact but gold seems to be safe to ingest? | Gold is non-reactive with the human body. It doesn't trigger an immune response, and it doesn't tend to chemically bind with anything important in our bodies. That's the same reason Gold doesn't corrode, it doesn't react with Oxygen to rust (oxidize) That's why Gold is edible and why it's often used in dental work. | 3 |
bnrfv4 | Other | Why do people write see ID on the back of their cards? | They think it’ll help prevent identity theft because the cashier will ask for id before allowing the transaction to go through. Now a days with swiping/inserting cards yourself, or tapping them, it’s fairly outdated. (Not to mention if they didn’t have ID or refused to show it, cashiers usually don’t know how to proceed. We aren’t trained to prevent identity theft like that.) In my experience, the times I would actually ask for ID, the person would usually become angry at the “inconvenience of it” and huff at me as they handed over their ID. I usually just didn’t ask because it wasn’t worth the possibility of being yelled at by customers for following THEIR OWN instructions. | 4 |
98ehyn | Culture | Why is the term "austerity" seemingly never used in the US? I constantly hear about austerity measures to reduce debt and such in European countries, but in the United States, I never hear conservatives/Republicans use the term "austerity" to describe reducing government spending. Instead they call it "fiscal responsibility" or "measures to reduce the deficit" or "reducing the national debt". Why does the US seem to not use the word "austerity"? Or do they use it and I've just been missing it? | Because the US is able to pay off its debts and there is no reason to believe this won't continue. Austerity starts when a country is in danger of not paying its debts. Fiscal responsibility is "the balance on our credit card is getting high, let's try to manage it a little better." Austerity is "they are about the foreclose on the house...sell the car, get a second job, eat nothing but beans and rice, do whatever it takes to keep the house!" | 3 |
7a5z7t | Biology | why do people gain weight as they get older? | Mostly it is that people don't work off the meals they eat. We are coming up on the holidays where just about everyone over eats. But most people never really pay for that over eating. So they gain a pound or two. Same goes for birthdays and vacations. You over eat a bit and don't work it all off. Well gaining a few pounds is nothing, but multiplied by 10+ years and there you are 20 or 30 pounds overweight. | 5 |
6kih6k | Biology | Why do some people have anxiety disorders and others don't? / What factors create anxiety disorders? | Step 1: get chased by predators for thousands of years Step 2: become a civilization with advanced technology where no one has to worry about getting eaten alive Step 3: Suffer from the genetic aftermath of anxiety that never went away, even when there is seemingly nothing to be anxious about On a serious note, it all depends! Some people are genetically predispositioned to have anxiety. You have to remember, every animal in the wild has some form of anxiety at all times. It's how they survive. We have just slowly over time gotten rid of the need to be anxious about stuff without actually getting rid of the anxiety part. Evolution is a slow son of a bitch! Other reasons are man made! Getting picked on in school, not having a stable home life, etc can all lead to anxiety in social settings or anxiety in any setting. It all depends! Bottom line is, you're lucky if you have no form of anxiety whatsoever. | 14 |
83etmd | Other | How do headphones end up getting tangled? | Simply - there are few ways you can position a headphone cable that would not be called 'tangled', but near infinite ways that it can be tangled. As headphones jiggle around, they end up in a random state - which most of the time would be tangled. It's just like how you might throw a dice 5 times. How often would you expect the numbers to come in an order? How often would you expect them to be mixed up? | 1 |
a3m04c | Biology | How do people develop stage 4 cancer without noticing until it’s too late? | Not all cancers actually cause symptoms until they are quite advanced. Notorious for this are gall bladder, oesophageal, lung and pancreatic cancer. By the time people even have any symptoms, and then wait a period to see if they will resolve before seeking help, the cancer is already advanced. Other cancers do cause symptoms much earlier, but people ignore them. I quite often come across people who have known something is wrong, but haven’t come to the doctor because they don’t want to be told that they have cancer. Ignorance is bliss. It’s a strange but common quirk of human psychology. | 2 |
9k041l | Biology | How do ADHD medications like Adderall and Ritalin work? What exactly do they do to the brain at a physiological level, and how does that work to treat symptoms of ADHD? | Think of the ADHD brain like a dry sponge: a dry sponge needs more water to function properly than one that’s already been wetted. This is kind of the case with ADHD and the brain, with dopamine—a chemical our brain cells use to communicate—as the water. A neurotypical brain is like a wetted sponge, and the ADHD brain is like a dry sponge—needing more dopamine for the neurons to communicate properly. The ADHD brain is constantly under-stimulated due to this lack of dopamine, causing people with ADHD’s brains to seek out activities that cause the brain to release dopamine—this results in many of ADHD’s symptoms. Stimulant medications—like Adderall—cause the brain to release more dopamine (Ritalin actually prevents the reabsorption of dopamine by neurons—akin in the sponge analogy to preventing water evaporating) so that the neurons do not need as much of the chemical to work properly and the brain functions more similarly to a neurotypical brain. | 15 |
lex6o1 | Biology | What impact does stress have on the growing brain? | Stress is terrible on the brain and body at any age. I'm 59 and I'm losing my ability to spell. | 10 |
6kiagh | Other | Why does it seem that U.S. construction projects, roadwork, etc. take so long to complete while in other countries it appears to be much shorter? | Regulations, EPA, unions and local/government safety guidelines. I live in Boston which has been under construction for 2 decades and a few friends in the industry here. The big dig double cost was just a scam job for criminals to take from the piggy bank on something little had done before. Now we bid out contractors to "save" money. It must be local unions and a certain number of hours for each crew to guarantee an even job force. They also require a cop on double overtime to watch it all. They tried flaggers for 1/3 the cost, but they had police protesting and driving the wrong way down street. They were complaining the flaggers told them to and were a safety hazard. Any money/time saved is lost elsewhere. Not against any of these things or groups; it's just how it happens. | 49 |