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6686cq | Culture | How did baby boomers when they were young manage to pay for a house and raise a family while on single incomes (the dad working), yet today young couples can't even afford a small home and struggle to raise even one child while there's two incomes (mom and dad working)? What happened? | I have no scientific sources, but think a lot of it has to do with population growth. 1950 the US had 150 million people (2.5 billion worldwide), now there are 320 million (7.5 billion) So much more people want houses, but the land area is constant, so the property prices go up a lot. On the other hand, there are much more possible workers, so the wages go down. Supply/demand. | 76 |
aqbady | Culture | Why does the school bus driver get seatbelts but the students do not? | If there is a fire the bus driver will not have time to disconnect the seat belts of every student. The students might panic and won't be able to. It's safer for the students to remain unbuckled. | 23 |
72fcc6 | Other | Why does the USA have a jury in court? Why would you have citizens without a law degree decide on such important matters? | Let's imagine you're in class and one of your fellow students comes up and says "Miss Twinkle, Lord Von Redditstein stole my crayons!" And you're like "Woah, hold on, I did no such thing!" But the hall monitor takes you and puts you in time out anyway. They say you're facing up to three missed recess periods for this crime, but you maintain your innocence. Miss Twinkle gets Mrs Star from next door to get her class of 5th graders to listen to the case. Mrs Star tells her students that stealing crayons is a crime and the penalty is up to three missed recess periods. The principal and the assistant principal then come in, one to prosecute you, to tell the fifth graders why they should believe that you did indeed steal the crayons, and one to defend you, to tell them why they should believe that you did not steal the crayons. They are present as the principals ask all the witnesses and help to determine all the facts. At the end the fifth graders vote on whether you stole the crayons or not, based on the assessment of the crime that Mrs Star gave and the evidence or lack of evidence of crime that the principals gave. The teacher and the principal know the rules of the school, they are experts in it, just like judges and lawyers are experts in the laws of a country, state, county, etc. And while the 5th graders might not know all of the laws, rules, punishments, or facts, they can listen closely to the experts who do know these things. They're not the ones decided if such and such is a crime, rather they're the ones listening to two people debate about whether a crime had been committed or not and in the end deciding -- essentially -- which argument was more convincing. It's not a perfect system, but it does allow some protection from an all powerful judge who could easily just find those guilty he didn't like and innocent when he did. With these people being students as well, they can put themselves in your shoes and go "Huh, the principal says that Billy saw Lord Von Redditstein volunteering in the cafeteria during arts and crafts time, there's no way that he could have stolen the crayons!" And boom, not guilty, no matter how much Mrs Star wants to put you away for three recesses. | 4 |
6sfhl1 | Physics | Why is a real helicopter so hard to fly but a $20 toy helicopter can be flown by a 6 year old | Quadcopter rely on sensors and electronics to control the rotor speeds. Single rotor Helicopters, even RC ones, don't rely on sensors feedback mechanisms. In an RC helicopter, it's servos and motor speed controllers that are tied directly from the radio control stick. In real heli's, they're physical mechanical linkages. | 8 |
5mvfb9 | Chemistry | If the FDA (US) so strictly vets new drugs for safe use on humans, why then do TV adverts contain so many warnings against side effects? The United States Food and Drug Administration is responsible for vetting and approving new drugs slated for human use. With such a massive amount of efforts being conducted at the federal level ($4.7b in FY14), why then do new drugs for treating simple things, like acid reflux, seem to cause more problems than they treat? | They test to make sure that the drug is better than the thing it's curing. That doesn't mean it's completely harmless. Most of the side effects are quite rare, but they have to list pretty much anything that anyone on any of the studies reported experiencing while taking the drug. | 3 |
9qz3t6 | Technology | How does a suppressor work on a gun? | Didn't see this posted in the comments, but a sub sonic round fired through a suppressor will be drastically quieter than other rounds fired through a suppressor. Example: [ URL_1 ]( URL_0 ) | 12 |
nvvxyy | Economics | How does lowering interest rates increase the value of asset of real estate? What are the factors that affect real estate prices? | Lowering the interest rate allows people to borrow more money. In a hot housing market this pushes the price upward because people can afford to pay more for a home they want. | 2 |
km3h2d | Physics | what happens if an object is pushed past it's terminal velocity? | Nothing much. If whatever's pushing it is removed, it will slow back down to its terminal velocity. Terminal velocity is the point where air resistance and gravity cancel each other out. In your scenario, gravity is pushing less hard than air resistance (because it's going faster than its terminal velocity), so it will slow down until it's back in balance. Pretty much the same thing that happens as gravity speeds it up until air resistance stops it from speeding up any more, except with the two forces reversed. | 4 |
ck8s7x | Economics | Why does China have such undervalued currency and Qatar have the most overvalued currency while both being highly export dependent economy? | Before going into exchange rates it's probably helpful to add some definitions. In economics, there is a concept of "fundamental value". This is a value that could be expressed in any currency but we don't actually know what it is for any particular good or service. Knowing it would require perfect information. When economists and analysts say that a particular asset is over or under valued they mean that the price that this asset is trading at is above or below that fundamental value. No one can ever really know if this is true but you can get good hints that it was true if it rapidly changes to a new price. So if you take two currencies their exchange rate might be 2:1 but that doesn't tell you if it's over or undervalued. That might actually be the fundamental value. For example, imagine you have 2 countries, A and B. They both have 100 units of their respective currencies (let's call them $A and $B). In all respects the countries are identical (population, jobs, tech levels, etc) except that the government of B is willing to borrow money at some positive interest rate. Now a citizen of A might think to themselves, "Hey I'd like to get me some of that interest but B is only willing to borrow in $B. So I'll go to some citizen of B and trade them my $A for their $B." Of course the citizen of A thinks, "That's crazy. Why would I take some crappy $A when I can earn interest of my $B?" So instead of trading 1 $A for 1 $B they might eventually agree to exchange 1 $A for less than 1 $B. The exact amount would depend on the interest rate that $B is offering. That's your exchange rate. In real life, investors make similar decisions. People buy one currency using an other currency based on if they think one is more valuable than an other. But in real life everything is much more complicated. When looking at the value of any given currency you look at all kinds of factors; what is the interest rate, what is the default risk, what is inflation risk, etc. Some countries try to create an official exchange rate by just stating it. This always fails and you end up with a black market where people trade the currencies based on what they think the relative values are. China does something different. The Chinese government regularly buys dollars with RMB and uses them to buy US debt (they don't actually own as much as most people think they do but that's an other discussion). Since China is buying a bunch of dollars they bid up the dollar (and consequently bid down the RMB). They are manipulating the currency but they are not really causing the RMB to be undervalued. They are actually using market actions to change the fundamental value of the RMB relative to the dollar. As I said above, no one actually knows what the fundamental values of currencies are. But we have a few measures that try to estimate it. Economists usually use something called Purchasing Power Parity (PPP). This tries to compare the price of two sets of goods. The idea is that when I spend a dollar, I should be able to get the same amount of stuff whether I buy it directly or first exchange the dollar of some other currency and then buy the stuff there. This is a messy measure because it leaves out things like transport costs, differences in consumption preferences and so on. A poplar alternative measure is the Big Mac Index URL_0 It tries to compare currencies by comparing the price of a Big Mac in different countries. The idea is that you can buy one just about anywhere on earth, it's within just about everyone's budget and it's simple. By that measure every currency except the Swiss Franc is undervalued. | 2 |
kytl8u | Other | Why are there different variants of sign language? Couldn't one form become universal and be understood by all people regardless of language? | Same reason there are variants of spoken language. Things like BSL (British sign language) and ASL (American Sign Language) evolved after the US had parted ways with the UK but before international telecommunications were invented, so evolved mostly separate. They each have their own, separate, hard fought, histories that I suspect many signers would be unwilling to give up. As a note - BSL isn’t “British English in sign form”, similarly ASL isn’t American English in sign form either. Sign languages often/always have a radically different language structure to spoken ones, including things like “spatial grammar” that doesn’t even really exist in spoken languages. In order to learn to read written English (in the case of people in English language countries) signers need to learn a completely new language - English - that is has almost nothing in common with their own. | 8 |
oa556e | Physics | How Do Military IR cameras work? How do those cameras manage to show you a clear picture opposed to heat cameras one can use to get to know where insulation on house for example is leaking? | Two completely different technologies. Heat cameras aren't looking for light, they are sensing temperatures and converting that to an image. That's why the images look all blobby and blurry. A lot have a feature where they do capture an image and use it as an overlay/underlay to the temperature info to make it easier to interpret. IR cameras emit infrared light like a flashlight, and then capture the reflection just like any other camera. Since it is primarily only capturing the infrared light rather than the full spectrum, the image is presented to the user as black and white rather than color | 2 |
a0bam7 | Biology | Why aren’t babies born immune to every illness their mother is immune to? | 1) the mother can provide passive immunity in the form of antibodies during breastfeeding. Those are temporary and not lasting. 2) the baby has its very own immune system that is separate from the mother's. The two do not interact or the mother's immune system would attack the developing baby and the baby would not survive. The immune system sees things as self or foreign. That's it really. The baby's system needs exposure and survival to develop immunity just like all other humans. Has to be taught how to be used. | 3 |
isa5o1 | Biology | - How do spiders build their webs horizontally sideways? How do spiders build a web across a horizontal plain with no downward angle? Surely that would defy physics... Eli5 | Spiders can dangle a thread to blow into the wind and snag onto another point. It's called a bridge thread. If we're talking orb webs, the spider will then make another line down from the center of the bridge and start working from there | 2 |
f2pkzi | Biology | Why is there a part of our nails that hurts to clip and a part that doesn't? | There is a part that is connected to your skin and a part that grows beyond. Clipping hurts accordingly. When growing, the nail gets pushed forward, and some part gets pushed beyond the part | 2 |
bbg5f8 | Chemistry | How do brands like Smartfood pop their popcorn so that it's so much fluffier than what I make at home? | There’s so many different types of corn, it’s unreal. They all make different sizes and shapes. You can buy variety bags of kernels and see for yourself! The cooking process can have an effect too. Hot air poppers will make a slightly different popcorn that cooking it in oil on a stovetop. | 10 |
7thisp | Repost | What's the difference between LTE and 4G? | When your phone displays 4G it means it's using an HSPA+ connection. HSPA+ doesn't meet the 4G standards (it's an upgraded 3G standard) but LTE does. Some American carriers decided to market hspa+ as 4G in order to compete with other networks who had true 4G (LTE). | 2 |
bjinsa | Biology | I know cracking your knuckles isn’t bad for you, but it seems like everyone has a different opinion on cracking your neck. Is it actually bad for you? Why/Why not? | Anyone else get the urge to crack your neck while reading this? Edit: but there are definitely more nerves in your neck. You could possibly pinch a nerve if you do it the wrong way. | 10 |
fq8sue | Psychology | what’s the difference between bipolar disorder and borderline personality disorder? Asking for a friend. | I'm not a professional and self-diagnosis doesn't help. however I'm bipolar and can tell you it's like a roller-coaster, some days it feels like everything and everyone is out to get you. Then you have days where you can do everything, you have all these Ideas that is going to get you rich, you make very rash decisions without worrying about the outcome. My SO often walks on egg shells not knowing what mood I'm in because anything can piss me off. And that's with me on meds. I've been on medication for over 25 years, some work for awhile, some make it worse. The medication never stopped the roller-coaster just makes the swings better. The highs aren't as high and the lows aren't as low. Just remember, there's help out there. Seek help and a good support system helps out. Tell your friend never be scared to ask for help. | 5 |
cslkaz | Biology | why plants don’t suffer negative effects from inbreeding | There are issues with inbreeding plants. A major issue is that they will all be susceptible to the same diseases. Bananas are all clones, and if there's a particular disease that develops, it could wipe out all of the bananas in the world. In fact the world used to commonly eat the Gros Michel banana, but it got decimated by a fungus in the 1950s and now we eat Cavendish bananas instead. | 2 |
a0hufn | Biology | What is CBD Oil and how does it work? | Short answer: It doesn't. Longer answer: It does have some documented beneficial effects for epilepsy and anxiety, but they're largely overstated by people who want to sell you CBD oil. Very minimal evidence exists for its effectiveness at treating anything else. If someone tells you it can cure cancer, run. | 14 |
ixgpkd | Other | How is it that when multiple animators are making something, they all have the same style? The clone wars for example, all the episodes have the same style, with the only change being effort/time spent going up. | There are internal style guide documents. e.g URL_0 | 3 |
5pvtwx | Other | How exactly did OJ Simpson get a not guilty verdict? The evidence seemed insurmountable | The short version is that to be convicted, you need to be convinced "beyond a reasonable doubt." Even if there is strong evidence, if the case is not made well, or if there is not faith in the strength of the evidence, that can undermine the verdict. In addition, things like police or investigators mishandling or making assumptions can damage the case. In the Simpson case, despite the evidence, the defense was able to convince the jury that there was enough reasonable doubt in the strength of the case presented and the evidence gathered that it was not enough to convict Simpson. | 7 |
5q3ul6 | Other | why does North America get so many more tornadoes than the rest or the world? I was reading that about 3/4 of tornados happen in North America. Why? | A long north-south stretch of relatively flat terrain known as the Great Plains. The cold air in the north wants to push toward the equator because of centrifugal force, which in turn displaces warmer, lighter air currently near the equator. By the quirks of the Great Plains' geography, these can pick up a lot of speed in opposite direction, so where they scrape the edges of each other, it creates a spinning vortex (yes, I know that is redundant) known as a tornado. | 2 |
alwmwl | Biology | How do we know whether an alternate medicine works or not when there are people around us who claim that their disease was diagnosed and cured by it? I specifically mean Ayurveda and homeopathy here. They say that Ayurveda has cured cancer without any nasty side-effects of chemo. We know that these alternate disciplines don't have proper diagnostic methods for most of the diseases because there were no microscopes or MRI equipment back then. Then they say they didn't need all those stuff and they diagnosed diseases just by checking your pulse or whatever. Doctors and scientists, please help me. Thank you very much for your comments and replies. | The cancer was cured through sheer luck / randomness. Who's to say the cancer wouldn't have cured itself if the person took nothing? If there was actually a cure that entailed drinking random juices, then it would be an actual cure and not an 'alternative' one | 29 |
b3t1bm | Biology | Why are humans more susceptible to sickness than our pets? | You meet more members of your species in a day than your dog will meet in its life. That provides far more chances for pathogens to spread, and encourages them to evolve efficient means of airborne transmission. | 3 |
9k5bq4 | Biology | Why does reading a book in a moving car cause nausea? | your provoking the situation the leads ot motion sickness a disconnect between your eyes and your inner ear your eyes are focused on the book(that isnt moving much) but your inner ear is registering motion to the brain this disconnect leads ot nausea | 2 |
90z3v7 | Biology | Why do hangovers get worse as you get older? | For me personally, I ran out of money when I was younger and I had to call it a night. Now, however, I can keep drinking long after I should stop. | 9 |
c2hemo | Chemistry | What exactly is dirt? | If by dirt, you mean soil, take a look at: [ URL_0 ]( URL_0 ) . As the other person said, soil is a complex mixture of different things, including sand, silt, and clay at various percentages (take a look at the triangular diagram 1/4 of the way down), lots of other trace minerals, and then lots of organic matter (plant, animal, waste; some alive, some deceased), and water. 'Dirt', as distinct from soil, is the mineral (i.e. dead) part or it is disturbed soil that isn't supporting life. | 3 |
awxa7p | Other | Why do astronomers assume for any planet to have possible alien life it has to have the same habitable zone as planets in our own solar system? I know it has to do with water so is it just a way to narrow down the millions and millions of planets to those in a similar habitable zone as ours because it's all we know? Or do most astronomers just write off the possibility if alien life having different needs to survive? | Basically, while we know that it is theoretically possible for non-water-based life to exist, we have no idea at all how that would work, and thus can't actually look for it. We don't have Star Trek-style "scan for life signs" devices. We don't know how to look for life that doesn't at least partially resemble that found on Earth, so we focus on looking for water because that is something we know how to do. | 4 |
864uz2 | Biology | How does a bird separate a seed from its shell? I have a bird feeder and watch the birds eat sunflower seeds with shells on all the time. They bite the seed, and spit out the shell, apparently eating the inner seed, and it all happens very quickly. How does that work? A human could do it with some effort, but our mouths are much larger, and it still wouldn't be easy. | It depends on the bird. You may be seeing finches. Finches have a groove in their beak, so they use their tongue to place the seed in the groove, then crack the shell and use their tongue to pull the kernel out. They're pretty fast about it. Some birds like chickadees have to take one seed at a time and take it to a perch where they peck away at it. Other birds like bluejays have the digestive system to just eat the whole seed. | 1 |
j8hkdc | Biology | If chemically nothing is ever created or destroyed but simply transformed, where does the matter come from when a sperm cell grows to a full body? I know obviously how the cell divides and becomes more and more complex over time. I get that the biological code is in the original cell, but where does the matter come from? In my mind, I imagine the first cell as an architect with all the blueprints, but without any material. It doesn't pop out of nowhere, right? | During the very early stages of pregnancy the fetus gathers nutrients and “materials” from glands in the uterus. After around the two month mark, a placenta and umbilical cord form which then serve as the source of nutrients, though they are still gathered from the mother. This is also why pregnant women can have extremely specific cravings, their bodies are secreting hormones that make them crave things the fetus needs. | 2 |
dfi3c6 | Physics | How is it that everything in life is in a constant state of entropy (where everything degrades over time), and yet it's the general consensus that the universe/life has naturally progressed on it's own? (Related to the URL_0 .beautiful post from this morning) I'm agnostic/atheist and still have a hard time wrapping my brain around this. | The universe experiences entropy increase as a whole (in theory), but that doesn't mean that localized organization is not possible. I can go to the beach with a bucket and shovel and take a disorganized section of beach sand and turn it into a castle (well, in theory. My building skills might not be up to the task), which is an organized structure. That might look odd, but in order to do so, I was breathing air, converting it into waste product, and using up energy from food I had consumed, converting it into waste product, as so on. "Life" is mostly a result of earth's components being able to make use of the radiation from the Sun. It may be less entropic than the Sun's radiation just bombarding the Earth uselessly, but even still using that energy leads to entropy increasing as a whole. It's like sticking a water bottle into the spray of a broken water main. Yeah, you can divert some of the water to yourself, and drink it to stay alive, but eventually you're spreading that water as well as opposed to it just spilling all over the street. | 4 |
msrfeh | Biology | How do pregnancy tests work? | Pregnancy tests check your pee or blood for a hormone called human chorionic gonadotropin (hCG). Your body makes this hormone after a fertilized egg attaches to the wall of your uterus. This usually happens about 6 days after fertilization. Levels of hCG rise quickly, doubling every 2 to 3 days. URL_0 | 3 |
6lxv7i | Other | Why are there normally protests at G20 summits? | Because G20 summits are where are the leaders of all the major economic countries of the world meet together. And if there's one thing you can count on about the leaders of those countries, it's that some group of people somewhere are angry at them about something. This, that, the other thing. Doesn't matter. Being a leader puts you in a position to piss people off with your decisions, that's just how it works, and you will almost certainly piss off at least one group of people 100% of the time. So, with all the leaders in one place, it's an easy place to find a bunch of groups protesting because they are angry about one thing or another and want to voice their displeasure to the leaders involved. | 1 |
j4dpay | Biology | Why does singing tend to neutralise people’s accents? | Singing and speaking have different neural pathways. There are people with brain damage who can't say the lyrics, but ask them to sing the song and they have no problem. There is no clear precise knowledge of why ans how that happens, but fmri studies show different neural patterns. | 6 |
gu5wdg | Other | What are job unions and what do they do? | A union is a group of employees who have organized in solidarity to collectively deal with an employer. Unions were started back in the early 1900s, when employees had few protections from abusive corporations. Laborers were often subject to long hours, low pay, and dangerous working conditions with no protections from being fired on a whim. The workers banded together because they were basically fed up from shit working conditions. They deployed a form of protest known as a strike, where all the employees basically agree to not come to work, until their demands are met in a bargain with the company via the union leaders. Many times, the striking workers would form a picket line - a human chain - a tactic to block replacement workers (scabs) from replacing them in their positions. Also, A union worker would also pay dues to their union, where the money is pooled amongst the workers to use for payments in the case of a layoff or strike, that would supplement their pay. Nowadays, unions are a lot different than the early days, and some would even argue that there isn’t a place for them in today’s modern workplace. | 4 |
bw46f8 | Physics | When you cut something in half, what happens to the stuff in the middle? Does it fall off or is it destroyed? Or has it just been pushed to either side? | short answer: it depends. things are made of atoms. atoms are extremely small. atoms bond together in different ways to make up hard objects. some of the ways they bond are strong, and some are weaker. when you cut something it breaks some of these weaker bonds and separates the atoms. & #x200B; so the stuff in the middle usually ends up on either side, like when you cut with a knife, or winds up as sawdust or powder when you cut with a saw. | 1 |
ekaedm | Culture | Canadian here. I'm having a hard time understanding the term 'deep state' as referenced in American political commentary. Can someone break down what that means or implies? Thank you. | It's an Americanism for the Establishment: a shorthand for the very real oligarchic influences on democratic government, generally via senior civil servants, advisors, consultant bodies and the ilk. Kind of laughable to have the Republican party talking about it, as they are the very fountainhead of oligarchy. | 12 |
iory4d | Mathematics | How does blackjack work for casinos? All the games have the odds in the houses favor, but isn’t the dealer essentially just a player in blackjack? Wouldn’t that make the odds of winning equal across players and the house? | There are quite a few things that each give the house a small advantage, and these small advantages add up. Not every casino uses every modifier, but some common ones include: Using multiple decks, including partial decks - this diminishes predictability Dealer wins on push - having ties be automatically decided in favor of the house Dealer plays last, unless dealer has Blackjack - it’s possible for every player for every player to bust without the dealer even playing Insurance - this rarely pays out to the player, and usually has a reduced payout | 3 |
6apjl9 | Other | Why do so many websites (mainly news sites) now have a "continue reading" button a few lines down the page? Why not just show the whole article to begin with? | It forces you to interact with the page itself, which shows that the content pulled you in. Helps them differentiate between you and users who might just keep going without using the site. That interaction can also harvest more data on you, such as the browser and platform you are using, etc. | 13 |
6r19tw | Biology | Why does blue light from a phone trick my brain into thinking it's daylight, but blue lighting in a movie or play makes it look like night time? | You are confusing two different things here. The first effect is a chemical reaction that removes the sleepy drug (melatonin) from our bodies when our eyes are exposed to blue light. The second is a theatrical representation of night time that is culturally accepted as a substitution for darkness because plays and films would be pretty rubbish if you just turned off all the lights to represent a lack of light. | 1 |
gg8vlk | Technology | Why do ads show up for things I’ve only talked about and not searched for online? | Marketing companies hooving up all of the data that they can. They use any piece of information that will increase your chance of buying something. Youll see it referred too as data driven marketing. How do they get this data? By trying to record your every action. Whether it be a app that is recording everything in the background and analyzing it, how you interact with a webpage, who your friends are, Location data, etc. Even your smart TV and Fridges are recording what you do. If you go and buy a movie ticket, there is a good chance that someone will buy that data and analyze what movie did you buy, did you upgrade to a greater experience, what did you buy at the concessions, etc. Though its worth keeping in mind that this process is almost entirely automated and a computer is just trying to sort through it to figure out what your most likely to buy Even your ISP will spy on you. Not just with supercookies but your DNS records, http traffic, etc. [ URL_1 ]( URL_1 ) [ URL_2 ]( URL_0 ) (You can stop this one by using a third party DNS server) | 10 |
eoifc8 | Other | How do we find full waves frozen in mid flow? Like they are crashing on the shore when they instantly froze? | If you're referring to the "frozen waves" in [Antarctica]( URL_1 ), those aren't waves. They are formed by pressure deforming the ice and creating odd formations or alternatively, melting the ice in odd patterns. If you are referring to the "frozen" waves in [Nantucket a few years ago]( URL_0 ), they weren't frozen. They were slush waves. They were still in motion. Note how water is spraying up where the top of the wave has curled over and begun crashing in to the slush below it. | 1 |
jldsic | Biology | Why does that skin layer form when you heat up milk? | let me simplify what u/fadedwiggles said. protein in milk gets hot and break apart and it also combines with milk's fat and..uh.. | 2 |
8y3rt2 | Biology | How do female astronauts deal with their period in space? I just watched [this]( URL_0 ) video of a female astronaut showing around the ISS, including showing the bathroom and how it works. I noticed that she didn't explain what happens if/when she or another female astronaut gets their period in space. | When Sally Ride went to space a NASA engineer actually asked her how many tampons they should pack for her one week trip and asked if 100 was enough. Copied from a web cache of an old popular science article. > By the 1970s, NASA knew that the cardiovascular system was greatly affected by spaceflight. Because humans evolved in Earth's gravity, our bodies got really good at fighting gravity to pump blood from the lower extremities to the chest, where that blood can be reoxygenated and recirculated through the body. But when there's no gravity to fight, the system gets sort of “lazy.” The heart doesn't need to work as hard, and blood and fluids pool in the upper body and head, giving astronauts the characteristic puffy face/chicken legs look. > Knowing this, engineers and flight surgeons weren’t sure if something similar might happen to a menstruating woman in space. If blood in the body pools in the torso and head, could menstrual blood float upwards and pool in the abdomen? Retrograde menstrual flow was a real worry because the consequences could be significant. Worst case, this could cause a condition known as peritonitis, an inflammation of the membrane lining the abdominal wall and organ inside the abdomen. Left untreated, peritonitis can be a life-threatening condition. No one wanted to send a woman into space only to have her die because of her body's natural cycle. > But there's a pretty big difference between blood circulation and menstruation (lots of differences, really, to be clear): the former is controlled by a network of arteries and veins that work all the time while the latter is controlled by hormones. **The flow of menstrual blood isn’t guided the way circulating blood is. So while male engineers were worried about retrograde bleeding, the female astronauts weren’t worried at all; they expected a period in space to be the same as a period on Earth and wanted to treat it as a non-issue until it became an issue.** The problem was, there was no way to prove the women right. Someone would have to menstruate in space to close the issue. URL_0 | 4 |
5nq30s | Other | Who is Brodin and what is /r/swoleacceptance all about? | It started out as a parody of the fat-acceptance movement. In /r/swoleacceptance people posted ironic stories about being oppressed in their lives because of their muscular physique ('swole' meaning muscular/ripped) in much the same way as people on fat-acceptance subs do. But it kind of evolved over time as members started making jokes about weight-lifting being a kind of religion, and eventually Lore was established, along with its own terminology. The whole thing was a joke, but it's actually quite a nice sub where people who are into weight training support each-other in a light hearted way. Brodin (based on the Norse god Odin) is the god to which we pray. He guides us on the Iron Path (weight training) towards a state of perfect Swolyness. We pray (lift) in the Iron Temple (gym). But sometimes we are tempted from the path by Broki (based on the Norse trickster god, Loki) who wants to stop us from progressing and steal our gainz (muscle growth). Sometimes we talk of being "swole of heart" which means that while a muscular physique is, of course, the most important thing in life - it is important to be strong on the inside too, and develop muscular feels. We end our prayers with the interjection, Wheymen (a pun on amen - many of us use whey powder to supplement our protein intake) - a call to Brodin to help protect our gains, and give us the grace to help others along the Iron Path, even though they may be weak or overweight. So if you wish to join us, Brodin commands us to help you and we will gladly offer encouragement and advice. | 9 |
o9us7n | Physics | --- Higher dimensions. just can't get my head around it. please. someone. I have read the book Flatland so i get how there can be a higher dimension but I just can't comprehend it. If you have a way it can be visualised or even explained a lil bit, please tell me. Thankyou for your time! | [this]( URL_0 ) is one of the best explanations I have seen on all the higher dimensions. | 7 |
9ew0xh | Biology | Why does holding my breath for a really long time stop the hiccups? Is is psychosomatic or is there a physiological reason for it? | Hiccups is caused by spasmodic contractions of the diaphragm, holding your breath keeps the diaphragm contracted, it's kinda like stretching a muscle to aliviate a cramp. | 3 |
5sa8ps | Other | whats the difference beween a politician accepting a donation and a politician accepting a bribe? | TL;DR: A surprisingly wide variety of things done for a politician could count as a "bribe," but *only* if done with the intention for the politician to perform a surprisingly narrow set of acts. According to recent Supreme Court precedent, to be a "bribe", there *must* be what's called a "quid pro quo", i.e., something done for a politician (doesn't have to be a payment directly to him!) to induce him to take some kind of *official* act. Let's unpack that a bit, starting with the "something done for a politician" bit. The stereotypical bribe involves handing a politician an envelope full of cash. While that still [definitely happens]( URL_1 ), particularly on the state and local level, it's so obvious as to be kind of, well. . . tacky, I guess. In the US anyway, a lot of what goes down in terms of bribery isn't direct payments to the politician as such, but nonetheless involves some kind of favor done for or on behalf of the politician. Possible examples: donations to a favored charity, pulling strings for the politician's kid, getting his wife a seat on some local non-profit board, etc. What makes the above a *bribe*, instead of just a friendly favor ("elite" social circles involve *tons* of mutual back-scratching), is when it's done to induce the politician to take some specific "official act," i.e., exercise some power specific to their office that only they can exercise. Could be almost anything, depending on the office in question, e.g., voting a certain way on a particular issue, approving an application, awarding a government contract, etc. But it does have to be an *official* act. Just because something is a manifest conflict of interest, in an ethical sense, does not make it a "bribe". There's a whole lot of what could fairly be described as "influence peddling," corrupt as the day is long, which is still not technically "bribery," pr even necessarily illegal, as it doesn't involve the official actually doing anything *as a function of their office*. Making introductions and endorsements? Making "friendly" phone calls to other officials over whom the subject official has no actual authority? Probably doesn't count. Certainly didn't for [Bob McDonnell]( URL_0 ), anyway. | 16 |
5xr0ow | Other | when an image of earth is released how come the satellites orbiting it aren't visible? | Relative size. Satellites are very small compared to the size of the earth, so you'd have to be zoomed in to where a satellite happened to be in order to see it. | 1 |
99abi9 | Engineering | How do nails pounded into wood create permanent walls for a structure? How do thin shards of steel in wood make a wall that lasts for so long? You think that wind, or shifting or whatever would pop all the nails out within a couple years. Is there a physics reason why this doesn't happen? | carpenter here. we use different types of nails for different nailing. the common types are 16p nails and 8p nails. 16p nails are long, and have a shear strength of about 500lbs. meaning one nail can hold 500 lbs. 8p nails are ring-shank. the shear is much less, say 100 lbs per nail. but the pull-out is incredible. it's nearly impossible to pull a ring-shank nail. btw, carpenters building houses use air-powered guns that can fire dozens of nail per minute. source: i fired a few hundred 16p and many hundred 8p nails today. edit: add a bit - 16p (p for penny. 16 penny nails) nails are used to build the "bones" of a house - the stuff that holds up the house. studs, joists, rafters, etc. fairly easy to pull out. 8p nails attach the "skin" on a house - the plywood that ties everything together. ring shank means the nail has lots of little ridges on the shank (shaft) of the nail, so once it's in, it's locked in, by the compression of the wood as mentioned by /u/Venic_ | 2 |
g8ahls | Physics | What exactly is a superposition? I’ve been looking for hours and can’t find a straight forward answer. I have no idea what people mean by “color” and “hardness”, but I heard they are supposed to represent momentum, energy, and mass, but idk which of them it is representing. Also, does this just apply to electrons and protons? After hours, I haven’t been able to find anything that says anything about anything. I am confused as hell, and need answers. Help would be appreciated! | Superposition is essentially existing in various states of existence simultaneously. We know it applies to particles (all particles), and it seems to apply to collections of particles, and may even apply to the entire universe. To tie it into things like quantum spin, it just means that if there are multiple states of spin a particle can have, then it simultaneously has all of them (at least until you measure it - more on that later). So if an electron can spin clockwise or counterclockwise, it's actually in a superposition of spinning both clockwise ad counterclockwise at the same time. That's not a typo - superposition means that it is spinning both ways simultaneously. Now we don't know whether it actually is doing that, or whether our limited knowledge or lack of access to what's really going on deep down (to be colloquial) is to blame, but from our perspective, the electron referenced above is truly and really spinning both clockwise and counterclockwise at the same time. To accept this, you have to drop all expectations that the quantum world of particles behaves anything like the classical world you can see, touch, etc. In our classical world, superposition seems not to exist (although Schrodinger's Cat implies that it does). There are various schools of thought about this - some say the world exists in superposition until we "observe" it (and there's plenty to discuss about what observe means), some say the entanglement involved in classical systems eliminates superposition at the classical level, some say it's illusory and that all possible quantum states exist simultaneously, including other realities where another version of you (which is NOT you) is reading this. But this is all way beyond ELI5. And if you're confused by it all, that just means you're on the right track - no one understands quantum mechanics (as Prof. Feyman says), but some people are able to follow the math and work out what it seems to imply. Regarding terms like "spin" and "color" as applied to particles - these are labels of convenience we apply that have at best a loosely analogous connection to how a particle behaves and the properties it has that distinguish it from other particles. While electrons have something we call "spin," there's literally nothing to spin the way we think of a ball spinning. It seems there is some feature of an electron akin to angular momentum, but it's not angular momentum. Still, we use the concept and term to do the math. Same with terms like color, flavor, etc. These are just labels used by physicists that represent distinct properties of particles and systems, but there's no color or flavor possible at the sub-atomic levels involved. Don't know whether this clears anything up or just leaves things murkier, but if it's the latter, you're in good company. Physicists will do the math, but generally won't claim to have any intuitive understanding of the ins and outs of quantum mechanics. | 1 |
dk4dx2 | Biology | Why is it that when we touch a very hot surface, we have the same sentation as touching a cold surface before the pain kicks in ? | reminded me of this old punisher movie: he was torturing someone to get information. well, "torture". he showed the torturee a flame grill thing, told him that the temperature can go up to 2000 degree celcius or something, and told him that when this was applied on his back, he would smell burned fat, but he will not feel the heat. instead, he would have the cold sensation. punisher just used the flame thing on a piece of fat and used a popsicle on his back. | 6 |
5n8xgh | Technology | Why can't my front windshield have those defroster lines my rear window has that defrost the rear window really quickly? | Automotive HVAC engineer here! My job literally is responsible for windshield clearing. As other people have pointed out, there are some cars that use the heated wiring up front. I sat in a Range Rover that had it. They were very, very fine zigzag wires across the windshield that could only be seen when focusing your eyes on it. When driving, it wasn't noticable in the slightest. Something that new cars have now is what's called a PTC. This is essentially an electric heater that provides warm air before the engine has had time to warm up the coolant running through the heater core. The air that comes out of it isn't hot, but it's still warm and instantly available on a cold day. Also, most cars offer remote start, which does wonders for clearing the glass in the morning. | 30 |
d4yfub | Technology | How can a group of hobbyists or whatever make a deepfake that sounds exactly like Bill Gates, while digital assistants made by the world's biggest tech companies still sound like robots? | Its not that they can't, its that they choose not to. Making a digital assistant sound too human could be uncomfortable for some according to a lot of market research. There is still a lot of trust issues abound when it comes to interactive technology so they risk alienating their client base by making the voice too human. | 7 |
gs25du | Physics | The sun converts about 4 million metric tons of its mass into energy every second. Does this mean that it's mass reduces significantly over the span of, say, ten years? 4 million tons a second is a lot of mass to be lost given enough time. Considering the fact that the sun is over four billion years old, does this mean that the sun was physically bigger when it formed? What about a couple of hundred years ago? Or a few years ago? Could the suns loss of mass imply that it's shrinking over time? | With questions like this I like to write it out. The sun loses 4,000,000,000kg of mass per second. Or 174,000,000,000,000,000kg a year. But it has a mass of 1,989,000,000,000,000,000,000,000,000,000kg | 6 |
6578f7 | Other | Does the opioid-related "prescription drug abuse epidemic" exist outside the USA? What makes it such a huge issue there and not so much elsewhere? | In the UK, we have around 1,500 opioid related deaths per year for 60 million people. URL_0 | 48 |
o9c50d | Earth Science | How do we decide where one ocean begins and another ends? | It's arbitrary. All of the oceans are a single contiguous body of water. Different organizations have different definitions of where the boundaries are, but the International Hydrographic Organization (IHO) is the main one, along with the National Geographic Society, various national authorities, and others. But none are any more objectively correct than any other. | 1 |
aqcjd9 | Chemistry | Why does wasabi and horse radish kick you in the nose unlike other spicy stuff? | The active chemical in hot peppers is capsaicin. Wasabi has allyl isothiocyanate, which, unlike capsaicin, is able to vaporize and get up your nose. Allyl isothiocyanate is also not oil based like capsaicin, so it doesn't linger as long in your body. | 3 |
9n1swp | Technology | What did people use home PCs for in the 70s and early 80s? | It was a mix of hobbyists and people who had some kind of business related reason to have one. Word processing and spreadsheet applications for bookkeeping were both a big part of the early appeal of owning a computer. | 3 |
jxroij | Other | Why does it take up to 2 years to make a two hour movie, but only one year to produce a 20 episode tv show season? | Your timelines are off, but I get the idea of your question Movies are meant for perfection. You have one shot to get it right or your movie flops. That means you spend a lot of time making sure each an every scene, shot, sound, everything is absolutely perfect. You spend tons and tons of time planning beforehand, than shooting, then (especially for CGI heavy movies) a massive amount of time in post-production actually making the movie look and feel exactly the way you want it to. This takes a lot of time and money. Because you only have one shot, it needs to be right. TV shows are designed and written to shoot fast and cheaply and almost pumped out like factory style. Each episode, scene, whatever doesn't need to be perfect, what it needs is to be done quickly and at the right price so you can move on to the next scene and next episode, audiences will quickly forget a scene that wasn't perfect or an episode that didn't completely nail it once the next one starts. They don't have a lot of effects (usually) so the post-production process to add those isn't very long or expensive. This is pretty much for all TV shows, except you're highest of the high-end budget shows like a Game of Thrones, which exist in a category all their own and are more movie-like, because they can afford it. | 4 |
ai53ql | Biology | Why has the average height of humans drastically increased over the past 100 years? How tall will humans be in 100 years? What about the year 3000? Is there a height that our bodies will definitely cap out at? | Sweden has had a "growth spurt" during the last century or so, but it's flattening out. 30 years ago, I was considered tall at 1.90, but, even though more are in that vicinity, it's still considered tall, and few are significantly taller. So, basically, the average is moving up, but the maximums stay pretty uch where they are. | 14 |
8capog | Biology | Why does travelling make you feel so tired when you've just sat there for hours doing nothing? | One potential cause is dehydration. One of my jobs was a road guy where I drove a minivan for 500 kms a day and I was exhausted. Then an experienced guy told me I was likely dehydrated. After that I took a large water bottle with me. Problem solved. This is also why small children get cranky one road trips. They're thirsty. We gave our kids small water bottles and filled them regularly. Problem solved. | 16 |
a5zapw | Economics | What is money, really? | It is literally just everyone agreeing that it has value. Some of it is printed as cash, but most of it is just someone recording its existence in a ledger, and everyone, especially the federal reserve blessing said existence. | 2 |
im6ddg | Other | why does 68 degrees F feel great outside but freezing indoors? | To throw my towel in the ring, I'm going to bring up exposure to sunlight. Here in the southwest US, being in the shade (or better indoors) makes a world of difference. 90F(32.2C) in the shade is nice, but in the sun it sucks. | 4 |
97w6bn | Biology | How do medical professionals seem to accurately predict when someone “is getting close “ to dying when the cause of death is vague such as old age or a long suffered disease? | EDIT: i am amazed and humbled by the kind words and beautiful stories shared here. they are treasures. please write them down so your sons and daughters can read them. I threw this list together really fast and posted it. imagine my surprise when i saw my in box and almost fell over. so i made some changes, mainly in explaining more thoroughly and in more detail to "explain like i am five". i also added a few, that i had forgotten. the list was very errr, cold and clinical and i did not convey my love for this work. some of your responses reminded me i need to address this. we live in a "youth worship" western country, often where the wise elders are forgotten, death and dying are hidden, not discussed, taboo, whereas at one time in our past, death was as normal as birth, with the working close to the land and animals, we knew and were familiar with the natural swing of life and death. we run from death, we do everything we can to make ourselves younger, and to avoid that inevitable experience we will all have. working for hospice allows me to become a part of an elder's life, to bring my support to them when it may be needed most. i consider it a calling to bring more awareness of the normal reality of death. and more awareness of the incredible sweetness of being able to support a loved one through their passage. i cannot convey to you the blessing of being able to walk with a patient from the beginning of their journey, to the end of their life. it is the most vulnerable, most tender of mercies to be able to have the privilege to witness that passage. if you have the opportunity to be present for an elder during this journey, please try to. It may change you forever in a good way. It is the most spiritual of moments I have had in my lifetime. You may want to even volunteer for hospice to be able to serve our wise elderly and walk with them through this time, to acompany them at a time they may be abandoned (it happens). You will be rewarded greatly. ______________________________________ Hospice worker 26 years. 1. Withdrawing from interaction. 2. No interest in food or water (beware, pt can aspirate at this point if forced to eat or drink). 3. 02 (oxygen blood saturation level often called "sats" or "sat level") levels dropping (70 and below), Normal is 90s. I find using the oximeter is very helpful. 4. Color changes.. skin can go very pasty and grey 5. Mottling of knees, elbows. Mottling is a kind of blue/ white effect on the skin that may look a bit like bruising. 6. Blueness of fingernail beds, slight facial blueness around nose, mouth. Blank staring at ceiling or corner and or talking to a family member long deceased. 8. Muscle wasting at temples and eyes sinking into boney orbits 9. Apneic and or shallow respiration. Near the end a patient will often start to breathe irregularly. This is called apnea and or cheyne stokes respiration. what you will see is the patient breathes, then pauses. then breathes again. this can go on for a while or it can be near the end. as the patient gets closer to passing, the pauses will start to be longer than the breathing. i.e. starting... 10 seconds of pause, 50 seconds of respiration. then 20 second pause, 40 seconds of respirations (i use the second hand of my watch to count). As the time passes, the pauses become longer and longer. This is the place of truly near death.. as the pauses become longer and longer, the pauses will gently last until the patient gently passes. it can be an almost seamless and very peaceful thing to watch. they drift into death, and you wait for the next breath, and it just doesn't come. these are the deaths one hopes for, the good deaths with family around the bed, as the patient literally just slips away. 10. Sweaty, hot skin and or clammy cold skin. 11. Small dove like sounds on exhalation. 12. Inability to interact verbally. Remember the sense of hearing lingers .. your loved one will hear you to the very very end despite showing no outward signs or inability to move or respond verbally. 13. Cooling of extremities (hands and feet). 14. Phlegmy sounds. This is what is commonly called the "death rattle". Pt cannot swallow their oral secretions at end of life and these may build up in the throat. The sound you hear is the sound of the inhalation and exhalation air going over around and through those secretions in the throat. Lay the patient on their side and the secretions can come out. There is also a medication that can be used to help with this (drops) (can't remember name of it sorry) but the medication can take a while to take effect. I have been told that though this is difficultf for us to hear, it is not painful for the patient. This can be hard. Sometimes the nurse can drain the mucousy secretions with a machine, but it is said that the more the machine is used, the more secretions are manufactured. 15. There is a type of respiration that is often seen near the end, and it is best described as breathing "like a fish out of water". Patient will often use auxillary muscles (like their shoulders and upper torso) to try to breathe. 16. Pain. A) Physical pain. What I have found is that it is very very difficult to die if you are in intractable pain. the muscles are tense and hard, the body is wracked, the pain becomes all encompassing. the goal is to make the patient comfortable and to ease pain. this could mean trying differrent medications to assist with pain reduction. I cannot tell you the many times that finally, once the patient is relieved of physical pain, they can RELAX and let go. B) MYTH.. we do NOT kill our patients with medications. this is ILLEGAL. What we try to do is find the balance of pain relievers that will allow the patient to be pain free, and also allow them to still carry on with their normal activities and at the end, be able to speak or communicate if they are able. example: some patients are in so much pain when they come to us, they are unable to do anything. with the right meds, one lady was able to take her crafts to her regular craft fair out of state with her hubby in their RV, for the last time, to say goodbye to all her craft fair colleagues she had known and worked with for 30 years. another man was able to go spend a last visit at the cabin he built up in the mountains. Another patient was able to go to disneyland with her family, one last time. Medications are a wondrous thing. We learn what the patient would like to do and we try to find the medications that will allow them to do that. We will often pay for a final wish like this. C) Emotional Pain. Sometimes called spiritual pain. releasing emotional pain can come with counseling with spiritual counselors and social workers (both available through hospice). At end of life there may be issues that are unresolved with family members that have caused patient deep regret and grief. EMOTIONAL PAIN CAN TURN INTO PHSYSICAL PAIN THAT NO PHARMACOLOGICAL MEDICATION CAN TOUCH. Although sometimes resolution may be impossible, our counselors do their best to help patient resolve conflicts and issues that are a burden to patient and a burden to the family members. NOTE: these resolutions could mean the diffference between a peaceful death and a difficult death. There is something we can see, a definite change of pallor, expression, something hard to explain, that can tell an experienced eye that it is soon. It is very hard to tell you exactly when it will happen but the above are some things to watch for. ______________________________________ Many of your comments were around hearing at end of life. Here's just one article. URL_0 | 58 |
7w08to | Biology | Why can't we control our heartbeat like our breathing? Usually we don't need to aware that we are constantly breathing and if we want, we can always control it. But we can't control heartbeat. Why is it better this way? | Think of all of the times in your life when you’ve controlled your breathing.. all the bad smells, hot ovens, swimming. Now think of all the times you’ve needed to stop your heart.... | 4 |
5w974x | Culture | How do cultures who use non-Latin characters (China, Japan, Korea, etc.) make their signatures "unique"? | In Japan we mainly use rubber stamps of our names. There are lots of little shops that will sell you a rubber name stamp. You can get cheap plastic ones or really expensive metal/bone ones. I have several, including one on the top of a pen I got as a gift from work. The security of them is somewhat dubious, but they are a part of the culture now and I can't see them disappearing any time soon. | 4 |
jpyaet | Biology | What determines if the pus in a pimple/cyst is liquid or more solid? | The other answer makes no sense. The real answer is that a cyst and pimple are different things. A pimple is a tiny collection of bacteria and pus due to a blocked gland that becomes infected because all the bacteria are trapped inside. The pus is a mixture of fluid from inflammation and dead white blood cells. This can go from thicker goop to thinner goop but is always somewhat liquid. Most commonly cysts are trapped bits of cells that aren’t necessarily infected. The contents of these cysts are more solid because it’s mostly dead skin cells that instead of being shed off into the world are being shed into the cyst. There is obviously a lot more to it and a lot of caveats but this is ELI5 | 1 |
ea5csw | Biology | How is it that Cows can consume the same fibrous grass that makes every other herbivores scat into tight balls, somehow manage to produce turds of such low density as to be called "cow patties"? ? | Ok so there are 2 types of plant eating animal. There are foregut digesters and hindgut digesters. Why are they called this? Because it takes a lot of time to digest plants and nature has evolved two ways of doing this. Foregut digesters do most of the digesting at the START of the digestive tract. Cows have several stomachs filled with digestive juices that do this BEFORE the food enters the intestine. Ever hear of chewing cud? That's a cow swallowing some grass, then regurgitating it up into its mouth to give it another chew. The idea is it's as mashed up as much as possible. Then digested as much as possible before getting to the intestine where the nutrients are absorbed. Hindgut digesters do their digesting at the END of the intestine. They normally have a very large appendix filled with digestive juices that digest plant matter. Just like the foregut digesters have in their stomachs. This means that they need to eat more plants. Because they digestion happens at the end, they don't get as much nutrients. So they need to eat more to make up for it. Some hindgut digesters like rabbits will eat their own droppings to give them a second pass. Because of the different nature of their digesting systems they have very different poop. If you look at horse poop you can actually see the grass blades. Cow poop, not so much. | 8 |
j5quog | Physics | why cant we see (most) stars during the day | The light from our sun is so bright that we can't spot the other stars in the sky. In some areas this can even happen just from man made lights at night. | 4 |
cjvgj0 | Biology | How old are the hairs on my body? I’m talking body hair not head hair. I know some hairs fall off but is there an average age of hair follicles? Are hairs on limbs older than, say, chest hair? Could I have a hair follicle that I’ve had since teenhood? And does a hair “turn” grey or sprout fresh as a grey hair? Does my ethnicity or where I live matter when it comes to hair age? | I can't answer the whole question, but I can answer the one part about turning grey. No, they do not turn grey while hanging off your head. Hair has color because of cells called pigments which are like color deposits (you can see them in your hair under microscopes, pretty cool!). When hair grows out of your follicles, it will keep its pigments forever. When you get old, your hair follicles have trouble producing these pigments. So as your hair grows out, the new hair is simply grown without pigment, therefore grey. Quick edit to try my hand at really ELI5: You have little hair factories on your body that always are pushing out hair, bit by bit making your hair longer. The factory paints the hair as it goes out, but when you get old, they run out of paint! So the stuff that is already painted stays painted, but the new stuff is just unpainted grey. But eventually the painted hairs fall off, leaving only unpainted hair. | 1 |
jr8l65 | Technology | How does the start/stop feature in newer cars save fuel and not just wear out the starter? | They have electronic starters (two starters) stopping the motor running for even a short period of time reduces emissions. | 14 |
jqmgqx | Biology | why do people get annoyed? What’s triggered in the brain to feel irritated and why do we have pet peeves? | Annoyance is essentially a stress response in your brain and body, which causes the release of hormones and neurotransmitters to help you respond to that stress. Some annoyances cause this reaction because they make things more difficult for you (annoyances like being made late, being hindered toward a goal, anything that means you have to do more work, do something differently than how you were planning to do it, do something faster than you wanted to, skip doing something etc). Some annoyances cause this reaction because they cause something called "cognitive dissonance." This is basically when your brain is getting input that is different from what it knows, which it does not like, as a rule. This would be annoyances like someone acting hypocritical (doing something that you know to be wrong, that they know is wrong, but they are acting like it's not wrong - this generates cognitive dissonance), or annoyances like people disagreeing with you on something you're passionate about. Some annoyances cause this reaction because they present potential physical danger (or something that your brain thinks might be danger). Examples might be a loud irritating noise, or an internal problem like hunger, lack of sleep, pain, etc. These and many other triggers make up the concept of "annoyance," and the stress response causes you to feel less relaxed and more vigilant (that feeling of being on edge), and somewhat blocks the transmission of certain relaxing neurotransmitters, like seratonin and dopamine. As to pet peeves and other individual differences in what people find annoying, this depends a lot on the learned pathways on your brain. If something has presented more serious issues for you in the past, or something frequently presents problems for you, it's more likely to annoy you more strongly because the pathways in your brain relating to that thing have gotten more "exercise," so to speak. Also, some things may cause stronger cognitive dissonance in some people than others, based on their unique set of thoughts and beliefs, causing greater annoyance when they are violated. Lastly, some people's stress responses are more finely tuned to be triggered by certain things, while others are more numb to the same thing. You can imagine how, if you grow up in a really noisy household, your stress response will probably not be as sensitive to noise as someone who grew up in a really quiet home, because you will be more used to it, and your brain will have learned that it is not really a danger or a hindrance. | 1 |
9nuh4v | Biology | When I'm awake, my body sends hormones to keep me awake. When I'm about to sleep, my body sends hormones to make me sleep. What would happen if my body did neither of those? | Probably become an insomniac. You would remain awake until you collapse from exhaustion. Your body would attempt to wake you up to go search for food. If it cannot wake you then your stomach eats itself until you die from dehydration. | 1 |
etj2w3 | Technology | Why are satellites put into "graveyard" orbits instead of being de-orbited entirely? ELI5: Why are satellites put into "graveyard" orbits instead of being de-orbited entirely? [DirecTV rushes to dispose of satellite that might explode ]( URL_0 ) | Most satellites that get put into graveyard orbits are in geostationary orbit which means they're 35,786 km above the surface of the Earth and orbit once per day. They're really far away and simply don't have enough fuel to deorbit themselves. The DirectTV satellite will be going into a graveyard orbit about 100 km further out than the standard geostationary orbit, its going to be really really far from any other satellites that we care about, and any debris that it creates will be in a similar orbit and unlikely to cross into the geostationary orbit ring that we care about. So how many satellites can you shift to this graveyard orbit? Well if you space them 100 km apart you can fit around 2600 satellites into that specific graveyard orbit, but you could also park some 150 km out or 200 km out. Space is big and its really easy to hide a satellite so its unlikely to ever bother anything you care about ever again. | 2 |
kmt1lq | Other | Why do we make road markings white, even in areas that get heavy snow? This has always bothered me. Why do they continue to make most road markings white, when they are almost impossible to see in any kind of snow? | If the road is covered in snow then it doesn't really matter what colour the paint underneath is, does it? | 2 |
9ua41g | Physics | What is Voltage? I’ve taken two years of physics in high school and can calculate voltage in circuits, but what is a definition of voltage that doesn’t use a bunch of formulas? | You can basically think of voltage as being like "electron pressure". It's how hard electrons are "pushing" between two points in a circuit. Even if those points aren't connected by a wire, there can still be voltage between them. Just like if you have water up in a water tower, and you close off all of the pipes that the water can flow down through, the water in the tower is still exerting pressure downward. | 3 |
ipvrne | Biology | why do humans feel the urge to lick cuts/minor wounds. | We are still just animals at the end of the day and have many associated instinctual responses. Saliva has antimicrobial properties, licking cleans the wound and clotting is promoted. There's a reason why other mammals do the same. | 3 |
77bvdo | Biology | Why is CPR for drowning different than CPR for people who collapse from heart problems? e.g rescue breaths are recommended for one but not the other. | Short version: Current American Heart Association CPR teaching is NOT different for pulseless victims of drowning. People who drown generally aspirate water, and experience respiratory arrest which leads to cardiac arrest (death.) AHA guidelines for an adult with no pulse and "death rattle" (agonal) breathing or no breathing is the same every time - check for pulse and breathing simultaneously for no more than 10 seconds. Delegate someone else to call 911 and get an AED. Start compressions. Perform 30 compressions followed by 2 breaths. Continue until the AED arrives. Turn on the AED. Follow the instructions. Continue CPR. Follow the AED prompts until the patient responds or help arrives. In drowning, there is an obstruction (inhaled water) that isn't allowing gas to exchange in the lung tissue - this is why it is very important to get advanced life support as soon as possible. These patients need advanced airway management, ACLS (advanced cardiac life support), and to be kept warm. Source: EMT, CPR instructor | 6 |
c2byrv | Biology | when you’re in the hospital and considered to be dehydrated, what exactly is the whole process of IV fluids? What exactly is in a “fluids” bag and how does it help? | If you're dehydrated and receiving normal saline solution, literally all that you're getting is distilled water with just enough sodium in it to make it *isotonic,* or matching the concentration of sodium in normal blood. Introducing this saline solution keeps your sodium balance in check, and keeps your cells supplied with water. Other issues might need higher or lower concentrations of sodium, but for normal cases of dehydration, you'll be getting normal saline. | 2 |
5vf245 | Biology | Donated human blood only has a shelf life of about 21 days, what happens to the gallons of un-used human blood if it never finds a recipient? | I read Jack Kevorkian's book for research on a paper about assisted suicide. In it he talks about having procured expired blood & using it to paint with. BTW, in an unrelated note, he wasn't right in the head. | 11 |
5xuxeo | Economics | Why is it so frowned upon to be friendly with Russia? | I've read a lot of comments, and I, as a Russian, want to express my opinion. I dont like Putun, neither I like his politics. But actions of your government harms us, russian people, not Putin. He only exploits these actions to show that you are our enemy and to unite the majority against common enemy (it's not that bad actually, just most people don't like your government). For example, Putin's rating increased to about 90% after Eu and Us sanctions. On other hand, prices increased significantly, and the quality of products dropped(russian cheese, for example, is just garbage). So I was really happy to hear that our relationship may stabilize, because I don't think that you can help us to get rid of him. It's our problem and it's up to us to help ourselves. I think we both can benefit from cooperation and it's better for the world. Sorry, for my English) | 30 |
5p24ne | Biology | Doctors : why has there been a female contraceptive pill for decades but only now is there one being made for men? | The Patriarchy. Kidding! Women naturally go through a complex monthly cycle which governs their fertility. They can only get pregnant during a very limited window. If she fails to become pregnant, levels of hormones such as estrogen and progesterone naturally fall in the body and the cycle begins anew. When we give oral contraceptives, we are supplying those hormones artificially, extending one of the nonpregnant phases indefinitely. When we take them away, she can resume her normal cycles. This system is reliable, extremely effective and has (usually) relatively minor side effects (though some of them can be fatal! So they're not right for everyone). In contrast, there isn't any natural process in men to easily take advantage of. There have been a wide variety of strategies employed but they have typically ran into things like...uh..making you sterile. Permanently. Or they don't work so reliably. Or they have other significant and potentially dangerous side effects. | 2 |
5tbwzu | Biology | It is estimated that some sharks lose over 30,000 teeth in a lifetime - where does a shark obtain the levels of calcium necessary for such rapid tooth replacement? | Well they don't have bones to worry about. We have a whole skeleton to upkeep, and we manage. But sharks eat a lot of things that have bones, and calcium in them, and what's more many calcium compounds can be dissolved in water, there are calcium ions just floating around the ocean, about 400mg/L of water. They don't really need anything to get calcium, they're swimming in a solution of calcium among other salts. | 1 |
ivj1fr | Engineering | Why is it since so many electronics and applications require batteries in pairs, there isn't simply one larger equivalent? | AAA and AA batteries both output 1.5 volts. If two are linked together in series, that increases to 3 volts which some applications need. Two AAA batteries are not worth a single AA battery in that sense. | 4 |
acpfth | Biology | How do Advil and Tylenol help with headaches and general pain relief, and does taking more make it work faster, last longer, or do nothing? . | Advil is an NSAID (non-steroidal anti- inflammatory drug) which, as the name implies, counteracts inflammation and therefore, pain. IIRC, the mechanism of action of tylenol's analgesic properties are not well understood, but it is centrally-acting (brain) to the heat-regulatory center (hypothalamus) to treat fever. I suppose pain control just follows from there. Perhaps there is a pharmacologic specialist who can help me here, too. Typically, the higher the dose, the longer the duration and more intense the effect. I need to qualify the above statement by adding my PSA, always use the lowest effective dose and dont EVER take more than prescribed. You can fuck some shit up. | 3 |
g0himw | Economics | Why are American stocks rising when unemployment rates are exploding? | Because profits is more important than people, and the federal reserve is printing money and is artificially creating value. With the initial drop, the logic is that now all that was priced in, thus increasing. However, what is baffling, compared to fundamentals of the market is that whenever bad news comes out about a company (i.e. Boeing, American Airlines, United and Delta), their stocks start climbing. If that doesn't set a red flag at the SEC, I don't know what should. | 5 |
9lppd1 | Chemistry | Why can’t one re-pop popcorn kernels that didn’t pop the first time around? | If I know correctly, there is a small amount of water in them. The first time, the water boils out with out popping. So there is none left to pop it the 2nd time | 2 |
7mdnnh | Repost | How does a diamond, the hardest substance on earth, still get shattered by a hydraulic press? | Hardness, as an intrinsic property of a material is understandably important but it is also easiest to define (see Mho’s scale of hardness); Other engineering properties however, such as Toughness and Strength, are not. On the Mho’s scale, every subsequently harder type of material will ‘scratch’ all materials that are softer. The second hardest substance for example - Corundum, that sapphires are made of, can only be scratched with a piece of diamond (which makes it an excellent choice for ‘sapphire-crystal’ glass such as on a high end watch). But in most cases, hard materials are almost always ‘Brittle’. Brittleness of a material implies that it is susceptible to shattering - the way that glass shatters. A hard material may be resistant to ‘scratching’ at the surface level, but at the bulk level, instead of deforming when struck with enough force or put under sufficient stress (like under a press) will fracture into smaller pieces. The most appropriate example to demonstrate these properties (in fashion with diamond) would be steel (both are crystalline). Steel is also extremely versatile and can be heat treated to either be Hard & Brittle or Soft & Tough (also see malleability and ductility). As an engineered implementation, Japanese swords make use of both forms of steel because neither is desirable by itself (hard steel can hold a sharp edge but can easily shatter and break while softer steel might be tough and resilient but fails as a sword). TL;DR : Hardness is not the only notable physical aspect of a material. There are only other equally significant attributes like Toughness and Strength. (Titanium shakes head in neglect) | 3 |
7fxfka | Culture | How does bowing work in Japanese culture. I've heard there are so many subtleties to bowing that a Westerner should never attempt it. Is this true? What are some of these subtleties? | White guy living in Japan for over a decade here. If you don’t look Japanese everyone here will assume you are completely ignorant of the culture and language and most indiscretions will be forgiven. Any attempt at anything “Japanese” will generally be met with happiness and cultural pride that you are trying and interested. The only things you can do off the top of my head to piss people off that you might not know to do or not do: don’t talk on the phone in trains or on busses, stand on the left side of elevators (or the right side in Kyoto/Osaka), let people get off trains before you get on. Maybe more, but that’s all I can think of. Edit: Whoops! Why did I say elevators?! I meant escalators! | 40 |
7shu6w | Economics | How is shorting companies not gambling? I understand how buying shares in a company isn't because that money is used to allow the company to function. But when you short a company, isn't none of the money going to the company involved so the investment has no direct influence on the outcome? | You misunderstand how securities are used. Companies only see money from selling stock when they first sell it to the primary market, which is referred to as an IPO. Trading between you and I is the secondary market, which the company does not participate in such profits and losses unless it is participating in the secondary market and its own stocks. Companies don't care about stocks, but it's management does, because it's not uncommon for executive and senior management to have significant stake in the company in terms of stock, and salary incentives and stock options as part of their compensation. So a company's interest in it's own stock is from derivative consequences, which I won't get into much more detail. A company stock can be worthless and a company can still function, even profitably so. Once you are invested in a security, you have what is called a position, which is a commitment that you will buy or sell. When you open a position by becoming invested, you can't realize the monetary value of that security until you divest, and close the position. Owning a stock is called a long position, and as a stakeholder and part owner of that company, it is a prospect that the value of the company will increase. You buy the stock at a low price expecting its value to increase, and then you sell it, and your profit is the difference (commission, taxes, and inflation not withstanding). So if there is a prospect that the value of a security will increase, is there a prospect the value of a security will decrease? Why yes there is. And that is your short position. You have to find a lender who will give you stock, and you are under contract to return to them their stock. You sell it at a high price, expecting the price to fall, when you buy the stock back for cheaper. Sell high, buy low, and profit from the difference. God help you if you break your contract with your lender, though. > But when you short a company, isn't none of the money going to the company involved so the investment has no direct influence on the outcome? That's just it, long or short, the money was never going to the company. And it does have an effect on the *market position* of the stock. This might be a tricky detail, but the exchange has no concept of long or short, only buy and sell, and the price of the last transaction. And remember, there is no selling without buying, and no buying without selling. Every position on the market is influencing the market - when you offer to sell your share at a given price, when you bid to buy a share at a given price, you are participating in the overall market decision of what the value of that security is. | 3 |
nzrbf6 | Biology | Why inbreeding causes offsprings to be inferior? | Concentration of bad mutations. Quite a few bad genes are only a problem if you have two copies of them. This is called a recessive trait. When inbreeding occurs there is a higher likelyhood that these bad genes will stack up since both parents will have the same bad genes. | 5 |
fv7o7t | Biology | Why do people have less energy as they grow older? I understand old age causes muscles to wear down and bones to ache, but how does this process start during someone's 30's? There are always people in their 30's or 40's complaining that they can't be out late anymore or can't drink as much as they used to in their 20's. What causes this? Does this happen to everyone? | There's a lot of reasons. Physical damage adds up, also things like your metabolism slows, your body produces less growth hormone, less testosterone and other hormones. That's just a part of it, if it was as simple as some hormonal changes then we could supplement those hormones. Most people 40,60,70 etc would kill to be as energetic and recover as quick as when they were 20. | 2 |
chbyli | Physics | If 25 degrees Celsius (77°F) is a comfortable ambient temperature, why does it feel so cold when you bath in water of the same temperature? | Water is more effective than air at transferring heat (feeling cold is really just another way to say heat was transferred from you). Air around you (assuming it's not windy) will heat up close to your body temperature quickly. You are now in your little heat bubble. Air doesn't take much energy to heat up. & #x200B; Blow a fan on you while it's 25C, and you now feel colder. & #x200B; Get into 25C water, and the water will do the exact same thing the air does, try to match your temperature, except that water takes a huge amount of energy to heat up compared to air. | 1 |
benrb2 | Physics | why are trucks and larger vehicles often slower even on a downhill? | Actually, if you let a truck just roll down a hill by itself it'll accelerate and accelerate and accelerate and...assumably crash. A truck will, literally, need to use the brakes all the time downhill, to maintain the same speed. Since that is pretty damn impractical (brakes that you use all the time get warm. Warm brakes are less efficient. Less efficient brakes means that you can't stop and...uh...again, that crash I mentioned earlier.) there is *an extra braking system* called a retarder. It's often an exhaust retarder. A hatch in the exhaust pipe that closes, so that the engine is literally choked by it's own exhaust fumes. By controlling the flow of the exhaust fumes (so, it's not *just* a hatch, it's a gradually controlled thing) it's possible to make the engine work *against* the momentum of the vehicle, rather than with it, as it usually would. Adding to that, if the truck is registered in Europe, it has a mandatory speed limiter. Kind of like cruise control, except it refuses to go faster than the government approved maximum speed. If you try to go faster (or go faster because you go downhill), the truck will activate the retarder, all by itself, just to ensure that you are not going faster than you are allowed to. | 4 |
i0ewra | Technology | What prevents an internet provider from offering higher speeds? I moved and the only provider available offers one plan. 3mbps for $49.99 a month. I feel like that should be illegal. | Absolutely no science behind my opinion but my first thought is greed. We pay for it but don’t receive it. | 3 |
bjprx6 | Biology | Why were prehistoric animals so much bigger than their present counterparts? | One thing to keep in mind: This is not a general rule, and visiting a museum can be very misleading in that aspect. Larger fossils are just easier to find and they get more attention because they are so unusual. Why were the largest (land) animals larger than today? See the other answers: A higher oxygen concentration helps, more food can help, competition can lead to that. But this doesn't mean everything else was larger. | 16 |
ez306h | Culture | Why are 'Dad Bod's' Veiwed so Positively and 'Mom Bod's' viewed so Negatively? | A quick Google search using the term 'milf' might change your mind on this. The fact is that making the claim that dad bods are sexy is in fashion at the moment. It is a trope that the media likes to use right now. That doesn't mean that they are objectively more attractive than six packs. | 2 |
hqy4z4 | Biology | Where do certain insects get their energy from if they don't eat and their sole purpose is just to reproduce and die? | All insects eat. They may not eat in their adult stage but as larva at least they do. To reproduce is the sole purpose of all life. Any symbiosis or pollination or anything else beneficial to other life ultimately serves that goal. To reproduce is the end all be all of life | 2 |