q_id
stringlengths 6
6
| category
stringclasses 12
values | question
stringlengths 5
4.6k
| reponses
stringlengths 28
9.92k
| response_number
int64 1
489
|
|---|---|---|---|---|
6w2hlh | Biology | Why do toddlers love to hand you things? I'm babysitting for my nephew (20 months old) and for the past hour we've done nothing but essentially play fetch. He's grabbed just about every toy in the room and runs to bring them to me. By the time I've tossed it back, he's grabbed another and is running it over to me with a smile on his face as wide as the Mississippi. I'm curious as to what part of development makes this so joyous for him. | Play schema is an interesting concept and it's the study of how all children who are developing normally go through various "schema" Rotation, Trajectory, Enveloping, Orientation, Positioning, Connection, Enclosure/Container, Transporting and Transformation are urges that show in all children starting as early as their first birthday, some times before. Handing you things is sort of "pre schema". It's the most basic form of interaction. Next, he may get into transportation and like to put things into something in order to move them elsewhere...or he might like positioning...so he will line stuff up. | 48 |
8wr9z1 | Economics | How do luxury watches like Rolex keep so many stores open when you hardly see anyone ever walk in there and buy anything? | Well the reason there’s hardly anyone in the store is because even if you had the money you could not buy the Rolex models that are most in demand. | 13 |
nn7iti | Biology | How do body builder’s bones support them when lifting high amounts of weight? How do body builder’s bones support them when lifting high amounts of weight? | Well, human bones are remarkable strong. If I remember correctly, your patella alone is strong enough to support the weight of an entire elephant balancing on top. While they’re not super resistant to impact forces, like landing hard or being hit, whilst they’re fairly well built to handle other things like weight or compression. The easiest way to imagine it is like having a long metal rod, and a hammer. If you hit it in the middle (simulating a fall or impact) it bends, but you can hit it a hundred times on top (simulating lifting) with little to no effect | 3 |
minra0 | Engineering | Why do old freezers slowly develop a massive build up ice which need deicing/defrosting, whilst newer ones don't? What technology has changed? | There’s tubing inside of the freezer behind a piece of plastic that zigzags back and forth so it looks like a squiggly line. Inside of that tubing is refrigerant and it makes the tubing very cold. Above the the tubing is a fan which moves the air across the tubing and through the rest of the freezer to make everything cold. Overtime, the tubing gets so cold that the moisture in the air will freeze to it. Eventually, it freezes so much that the ice can prevent the fan from working and moving the cold air around. Once that happens, the cold air just settles to the bottom of the freezer and the rest of the freezer gets warm and your ice cream melts. With an old freezer, this is when you’d have to defrost it. With new freezers, there’s a small separate tube under the cold tubes. The small separate tube is sometimes on a timer or hooked up to a temperature sensor. Once the timer reaches the set time frame (like every 24 hours) or the temperature sensor gets too cold, the small tube will heat up really hot. Because the small tube and the zigzagging tube are behind a piece of plastic and because hot air rises, the heat from the small tube is forced to travel up and around the zigzagging tube which melts all of the ice off of the zigzagging tube. The ice melts and falls down into a tray in the bottom of the freezer behind the plastic and another piece of tubing allows the water to drain underneath the fridge where it can evaporate into the air. | 3 |
76htpp | Technology | What is the difference between a GPU and a CPU? Which would yield higher gaming performance? I'm trying to upgrade my computer for the first time ever. It was a prebuilt one that is seven years old now. I'd like to think I am knowledgeable in the subject but I'm really not. I don't have a lot of money so if I were to buy one thing that would help me catch up to play better looking games I need to understand the difference between a CPU and GPU. I thought a graphics card was all I needed but I see talk of CPU increasing FPS. | GPU is what makes your graphics pretty. CPU is what makes your computer think better and faster. CPUs don’t really need to be upgraded that often. I have a gaming desktop from 2012 and my CPU works fine on max ultra settings for most games. However, it is the GPU which I had to upgrade since then. CPU is mostly notable for games which require a lot of computation but most games just make the GPU do all the work. Get a decently priced i7 (no need to go crazy) and get a 1080 and you’ll be set for another 5 years. | 2 |
hb88qx | Other | - Why is Uncle Ben's Rice Logo/Brand Name Racist? | Some people add the “Uncle Tom” connotation to it, a literary character with widely unacceptable racial tones in today’s society. Iirc Uncle is also a term that was used for the eldest/highest of the house boys who, by virtue of their position in the owners household, had seniority and rights over the rest of the estate slaves, as kind of a sergeant in the ranks. | 6 |
8lk7ic | Technology | Why can movies run at 24 frames per second and look relatively smooth, but if video games run at 24 FPS they seem very choppy? | When a real camera capture a frame, it capture ~~1/24th~~ 1/48th of a second worth of information (see below). Moving objects will appear blurry, so a single frame will still give a some sense of movement. Video games don't do that. They simulate the world frame per frame. The world doesn't exists in between frames, there is no real movement: objects are basically teleported during the simulation. This means that when the game renders a frame it can only display the world as it is at this exact point in time, all information about movement is lost, it thus need to display at a higher framerate to appear as smooth as a real camera. [edit] Motion blur tries to circumvent this (by computing the difference between the current and last state). While it helps a bit, it is an approximation (like anything else in real-time CG) and isn't as good as true, physically correct, motion blur. | 1 |
633u1m | Other | Why are they trying to remove Earth monitoring from NASA's budget? Neil Degrasse Tyson just mentioned his opinion on the matter in an AMA. What's the back story? | There can only be speculation with this question but one may jump to a conclusion that Trump as president is/will pass stuff that benefits his business affairs and interests. While I don't believe Trump has any ties to any fossil fuel companies; he can very much so try to disprove climate change for himself, others or just out of pure negligence. And, how he is trying to disprove climate change is by saying it's fake and not allowing any research to get done to backup his claim. | 9 |
eg4ua8 | Biology | How come canned fish have crumbly bones? I opened a canned tuna and found bones that were crumbly. It wasn't like how fresh fish bones feel. | The high heat of the pressure cooking that is used in the canning process breaks the bones down to be soft. | 2 |
9azwnv | Economics | Why has the price of college tuition skyrocketed? | Schools have no incentive to keep costs low, because students keep paying the ridiculous costs. Students keep paying the ridiculous costs, because they're not using "real" money up front—they don't understand the real costs until after they graduate and start paying the bills. A nation full of 18-year-olds takes this risk, though, because they've been fed the lie you *need* a college degree or you'll never have a fulfilling career. Schools also have no reason to keep costs low, because loans are federally insured. This means they'll get their money one way or another. They can price as high as they want, and people will continue to pay for the reasons previously stated. Throw in a bunch of overpaid, do-nothing administrators to increase the overhead even more, and you have the next economic bubble. **Edit:** Formatting. | 3 |
lbmodb | Biology | how does a solid like asparagus seems to go straight to urine within 30mins, instead of stool 3 days later? what other solid have this same impact? | Are we asking if you pee asparagus instead of pooping it? | 6 |
92ot70 | Economics | how do restaurants that sell extreme portions of food for a very low price (like a giant slice of pizza for a dollar) stay in business? | If a store like Costco is selling food for that cheap, it's because they are luring people into the store with that, and not trying to make a profit on it. Just like you'll see Target selling 12 packs of coke for $2, they use that as a "loss leader" to get customers into the store where they hopefully will leave with tons of other items. However you won't see Dominos or Pizza Hut doing that, because they need to have their pizza turn a profit every time. | 6 |
fr0lp9 | Biology | Does "flattening the curve" actually reduce the total number of people infected, of just delay/spread-out the timing of their infection? | You may get less cases overall but that’s not the aim. The point is to prevent hospitals from being overwhelmed at one specific time. Instead they deal with a more gradual increase and an extended peak but one that’s far lower than a worst case scenario apex. | 7 |
mw4blo | Earth Science | Why is Southern Europe considerably warmer than Canada which sits on the same latitude? | Air and ocean currents. Western Europe in general has a bunch of warm water coming up from the Caribbean through the Gulf Stream. Meanwhile, the bit of North America where most of Canada's people are is sitting right under a big air current that pulls cold air down from the North. Also, the west coasts of things tend to be warmer than the east coasts because of the way Earth's rotation influences currents. | 18 |
apgz4r | Chemistry | Why can't you feel contacts when they're on your eyes? | The same way your eyes filter out the fact that you can clearly see your nose all the time. | 8 |
5ututa | Chemistry | Why is coffee almost impossible to be reheated without it tasting burnt and is there anyway to prevent this? | Coffee tastes different when it's been sitting out for a while because compounds in it become oxidized from exposure to the air and because the high temperature (for hot coffee anyway) accelerates chemical reactions which ultimately affect the flavor. There are other factors that affect staling of coffee but the big ones are oxidation and temperature. These chemical reactions can't (realistically) be reversed so you wont ever get the freshness back, and by reheating old coffee you'll only increase the rate of chemical reactions which lead to it being stale in the first place. If you kept brewed coffee somewhere with no oxygen and at a low temperature then you could reheat it later and it would probably taste fresh. Once you pour coffee into a mug and it's exposed to the air and ambient temperature then it's just a matter of time before it becomes stale. | 6 |
5moo37 | Economics | What's going on in Mexico right now with the raising of gas prices and other amenities? Why are people looting stores and pissed off? | Some context is needed first. For years, all energy products had to be purchased through a monolithic organization called Pemex which was the only entity in Mexico allowed to purchase the product from the producers. Pemex then sold this to distributors, sometimes using heavy government subsidies. In 2013, however, the government passed an energy reform bill that was to remove power from Pemex in phases that kicked in at the beginning of the year. This was to make the market more competitive, and made Pemex go from having a government-sponsored monopoly to being a government-owned competing business. Over the past year, the Mexican Peso has devalued significantly from the last few years hovering around 13-15 pesos per US dollar to today's price of 22 pesos per dollar. Oil, being handled in US dollars, would thus be relatively more expensive as the peso has devalued. However, because Pemex still controlled gasoline they heavily subsidized the price of gasoline to remain relatively stable. The 2017 phase of the energy reform kicked in at the beginning of the year though, and has raised the price of gas to be more in line with what it should be. It should be noted that the government is STILL somewhat subsidizing gas, and that people's requests for the government to subsidize gasoline again would just add to income inequality by putting money hand over fist in the hands of the rich. The other request people have is to lower the amount the government taxes gasoline from the current 3.5 pesos per liter of gasoline, but this will put a heavy dent in the government's income. It's a difficult situation all around | 2 |
b9cgvd | Biology | Why do babies cry immediately after exiting the womb? | Somebody may correct me if I'm wrong but I think it's mostly because it's pretty painful to change from breathing uterus liquid to air. | 2 |
a55x1k | Engineering | Why do Russian/Soviet fighter jets have a distinctive look over their western counterparts? Do they have different understandings or knowledges of engineering? | They serve similar functions but were designed by different people with different design philosophies in isolation. You’d think they’d become more similar over time, even if that isolation continued, but aerospace is different. Change is expensive and risky so remnants of old designs remain because they work. | 2 |
6pz5kg | Repost | Why are under cooked burger patties are safe to eat? | It's basically... not. Everyone eating a medium rare patty that's not recently fresh ground from a whole steak is risking food poisoning. You just luck out more often than not due to meat processing factories keeping to pretty strict cleaning routines. | 5 |
86b93l | Biology | Characters in movies that wake up in the hospital, only to pull out all their IV's and tubes to walk out because of plot reasons, you couldn't do that in real life could you? What are all of those for and what would happen (if anything) if you did just yank them all out? | One time I was hospitalized from drinking too much. I was still drunk when I woke up and tried to sneak out of the hospital and ripped out the IV, the nurse caught me trying to run away lol. She made me get back to my bed and called my friends to pick me up and proceeded to tell them I sucked my thumb the whole time and that I asked for a pacifier (I doubt I really did), they still make fun of me for that. | 11 |
67mncg | Culture | The significance/obsession of USA citizens with prom and high school graduation. Is there something that I'm missing here? I thought it's normal to finish high school and prepare to go to pre U than Uni. But after seeing limousine being rented, hundred plus USD dress, another hundred plus USD for shoes, and top that with another couple of hundred USD for other necessary stuff, I'm questioning my own logic. It doesn't stop there, it seems, graduating high school is widely celebrated even to a point that parents give out paid vacation trips or a car as gift. As for the students theme self, OMG they spent months preparing for prom and the fight for Queen and King is actually real. I thought it was just TV shit. Back to the question, why? what is it I'm missing here? | Celebrating high school graduation is a tradition carried forward from the early 20th century when graduating from high school was not as prevalent as it is today. Back when my grandparents were young, maybe 50% of students actually completed high school, as many opted to drop out and take up working on the family farm or the family business. Of those who did graduate, maybe 20% actually went on to college as there were no student loans at the time and you really didn't need a college degree to get a decent job. So, in those days it was a pretty big milestone to actually graduate high school, as most people would then move on to full time work and essentially be considered adults. This carried forward for many years, even into my parents generation, where the majority of kids did make it through high school, but only about 50% went on to college. Again, the other 50% started full time work. This traditions has been carried forward through each generation. Also, of note is the fact that upon turning 18 and graduating high school, you become eligible to be drafted to the military. At times of war, this was a big deal, like during WWII for my grandfather or Vietnam for my father. As far as prom goes, this is essentially a coming of age ceremony in the USA. Seniors have their first truly formal dance as adults. As far as expenses go for prom, it is really a function of the economic status of the students that attend any given school. As you can imagine, students in wealthy areas spend a lot of money and student from poorer areas spend less. My high school was mostly upper-middle class and some upper class, so some people went crazy, but most people were spent around $300 or $400 total. We had rented a limo, but it was split between 4 couples, so it only cost me around $40 for my share. My suit was rented for about $100 and a group of about 40 of us rented a giant beach house for the after party, which I think was about $100 per person. Most people form groups that pool resources to have an awesome party, but at reasonable prices. Of course, the movies aren't going to depict an average prom, so those only show super extravagant and somewhat unrealistic depictions of prom. So, really prom and graduation are time honored traditions here in the USA. Does it make as much sense these days? Probably not, but I'm not going to turn down a reason to have a giant party. | 5 |
kyhajr | Chemistry | why is it so much more difficult to wash oil off plastic containers than glass or metal ones | Plastic is porous in a way that oils like to slip in to it. Which is why greasy and oily foods can colour the container, especially when the surface is worn and scratched. Meanwhile metal* and glass isn't. (Steel and aluminium are, but not so much that oil or greasy can soak in to the structure in a practical sense, but give it a long time and you'll never get that smell out of it). | 1 |
958o4e | Other | Why is it against the law to make false statements to the FBI but not against the law to lie to other law enforcement agencies in the US? | Cop here: The FBI is federal law enforcement that operates under different rules than state or local law enforcement. In my state, lying to a police officer can be considered a crime under certain conditions, like giving a fake name. In my state it's the same as resisting arrest, which is a catch-all charge for obstructing in general. | 1 |
ksaybl | Technology | How did technology grow so fast only in the last 200 years? And especially enormously in the last 40 years? Did humans become more intelligent? | 2 words: Exponential growth. And the beauty of it is that it only requires one circumstance: the rate of change (=progress) depends on the amount of stuff already there. The more you know, the better you can generate new knowledge. The more tech already exists, the easier it is to build better. | 12 |
6j7zfd | Culture | What is Cultural Marxism? A term I often seen tossed around, it is often used as derogatory, and I would like to know why. As well, who coined the term? | In it's original usage, it refers to the Marxist critique of culture and society. Broadly speaking, this *critical theory* suggests that the social superstructure must be reproduced with every generation, and that this reproduction is done through codifying the dominant ideology of society through culture, media and daily interaction with society. In this way, culture reflects and promotes systems of oppression, inequality and injustice. In that context, "Cultural Marxism" is typically used as a criticism by more orthodox Marxists who feel that viewing culture through the lens of race, sexuality, gender, disability, etc. detracts from analysis of the class struggle, from which all other forms of inequality ultimately originate. In 99% of cases today, however, the exact phrase "Cultural Marxism" is one used by right-wing, reactionary movements to refer to a conspiracy theory that the advancement of progressive ideologies within culture, media, academia and society is the result of a deliberate plot by the secret rulers of society (the Jews, left-wing academics) to undermine Western civilization and control the masses. It is the Nazi theory of "Cultural Bolshevism" with a slightly different name. | 2 |
n3h037 | Mathematics | If math is a such a definite subject with solid answers, how are there still unsolved math problems? How do people even come up with them? Edit: y'all have given me a lot to think about. And I mean a lot, especially as someone who has failed more than one math class lmao. I appreciate the thoughtful responses! Edit 2: damn, I'm glad my offhanded question has sparked such genuine conversation. Thought I'd touch on a sentiment I've seen a lot: tons of people were wondering how I'd come to conclusions that would bring me to ask this question. I'm sure it's not just me, but at least in my experience vis-á-vis the shitty american public education/non math major college, math ain't taught very well. It's taught more as "you have these different shaped blocks, and they each have a firmly defined meaning and part of that meaning is what they can do to the other blocks. Therefore we know everything the blocks can do, or can at least theorize it" and less "the blocks can be held and put together in infinite ways and be applied to infinite things that have yet to be fully imagined or understood and we're still coming up with new blocks every now and then". Buuut now I know that thanks to reddit! | Mathematics is a Hydra. Everytime we solve a problem, we see at least 2 new rising up from that. | 31 |
cdk4j6 | Culture | Why are silent letters a thing? | In addition to previous answers about letters originally being articulate or to mark etymology, one other cause is that there are more sounds in English than the Latin alphabet, so inevitably the leftover letters either have to have new letters created for them, or just use combinations of existing ones. When the language became standardized due to the printing press and education, extra letters dropped out of use. For example, you know that "Ye Olde Shoppe" thing you always see in things? In addition to the final silent e's which used to be pronounced, the phrase has another history hiding in there: the "Ye" is actually a simplification of "Þe" where "Þ" is capital thorn, the old letter used for what we now use the digraph "th" for. The letter "Y" happened to look like a capital thorn to English speakers then, so that's why it replaced it when things were getting simplified and standardized. Add one more change down the timeline, and you realize that the phrase is really "The Olde Shoppe." | 17 |
h08sfz | Physics | How do scientists know that nuclear fusion is the source of energy of the Sun? | Nuclear fusion is a comparative really recent thing we figured out. It was only in 1904 that we suggested it. Before that they thought the sun was powered by the heat of a gravitational collapse. IE the heat made when stuff was falling down and hitting other stuff. Lord Kelvin (the guy that scientific temperatures are named after) did the math, and concluded the sun had to be 20-400 million years old. Later on, we found many things on earth that were obviously older than that. So, something had to be wrong. So Ernest Rutherford suggested that maybe nuclear decay was heating it up in 1904. By 1920 we figured out that fusion could happen, so that was proposed by Arthur Eddington with hydrogen being a possible source. In 1925 Cecilia Payne use spectroscopy to figure out that the sun was mostly hydrogen. That is she study the light coming from the sun, and certain elements emit certain kinds of light. So they knew hydrogen could fuse to make energy, the sun was big enough to cause fusion, and there was a lot of hydrogen. So put it all together, and they concluded the sun fuses hydrogen to make energy. | 3 |
646sz4 | Culture | How did the USA get the "I have the right to be offended and you shouldn't offend me" culture when they have protected free speech? | Freedom of Speech is only with regard to the federal government. From the Constitution: > Amendment I > **Congress shall make no law** respecting an establishment of religion, or prohibiting the free exercise thereof; or **abridging the freedom of speech, or of the press**; or the right of the people peaceably to assemble, and to petition the government for a redress of grievances. | 28 |
5zbcfl | Other | How do they crack/break glasses in movies (without CGI)? I know that they use prop glass/sugar glass in movies. But how do they break glass on their own? Like maybe for a scene where a telekinetic breaking a glass door or explosion wave shattering windows. Edit: I'm asking about the mechanism the production team use to break the glass on its own to shot a scene where, well, the glass breaks on its own. | They put a little spike in the glass frame that, when triggered, shoots into the side of the glass | 1 |
5sacqb | Physics | When holding a seemingly heavy small object, why does it seem to weigh less if it's in a large box? | It's won't always but your points of leverage are much better if you can keep your shoulders square and keep the load as close to your torso as possible. A small object will force you to carry it at at a hunch and pull your shoulders inward which puts more stress on your spine and takes away good lifting form. | 3 |
mhqeim | Biology | Why does hearing yourself speak with a few seconds of delay, completely crash your brain? | Former FOH engineer here. It actually starts at around 110msec for most males, and peaks about 200msec. It is called delayed auditory feedback. Most females are not affected at all, perhaps due to females being better at multitasking. (My thoughts). Ironically it helps some stutterers. | 22 |
lvmzim | Other | What is a drycleaner? How exactly does a person clean clothes without getting them wet. How does a person dry clean clothes? | "Dry" is referring to not using **water**, not not using any liquid at all. It's just washing with non-water solvents, often tetracholorethylene or other halogenated solvents. | 4 |
6mimi2 | Biology | Why do babies eat anything, then become extremely picky, then slowly start having a wider palette again? | It varies from kid to kid - go watch the mostly silent "Babies" movie to see how nurture impacts behavior. My babies eat *everything* - no picky behavior at all. (One eats broccoli like there's no tomorrow). They would eat rocks, sand, seaweed and crabs on the beach if I'd let them 😝 They do reject food say if it's too warm/hot/cold or if the want something hard/chewy (if they are teething). Older kids tend to associate food with other qualities of social learning and so develop that picky behavior... until they are old enough to be curious again through self or social interactions. Note, some adults never expand their palette again. | 9 |
9xokwz | Biology | What kind of cells are generated in scars? Why are some different than its' original cells Are the cells generated in scars more generic version of its nearby cells? How is it that the liver can regenerate its cells with its original function, but scars, where hair used to be, doesn't grow hair? & #x200B; & #x200B; | The cells produced are "backup cells". They are long cells arranged parallel to each other in order to regrow as fast as possible. Unfortunately, these cells are not as strong and may not match the original tissue. | 1 |
h0x6ck | Chemistry | If a poison is expired, is it more poisonous or less poisonous? | It really depends on two things 1) what dows the expiration mean, is it a reagent with a specific purpose? It may be expired but still quite lethal 2) what does it break down into? | 5 |
hk3bjw | Biology | How can competitive eaters digest and eat all that food in one sitting? | Your stomach is a muscular organ and is able to expand and shrink based on use. Competitive eaters train to expand their stomachs to hold more food. Also when you eat the food is held and broken down by acids in your stomach for hours before it passes through your intestines to be actually digested. This means that technically the competitive eaters are probably not digesting anything during the meal. | 1 |
ac6fd9 | Physics | How can the same side of the moon always face earth? Doesn't it rotate? The fact that the Chinese just landed on the dark side makes it seem stranger. | The dark side of the moon is actually the light side of the moon in terms of mass, the heavy hemisphere points towards the earth, imagine a half filled ball in a pool. | 115 |
dlmb0l | Technology | Why are there still BLACK BARS on the top and bottom of some TV shows and movies despite viewing them on a widescreen TV? | Cinema is often shot at 2.39:1 (that was intentionally wide in order to differentiate films from 4:3 television). When it was relatively new, movies could be considerably wider. A few movies from the very wide era, remain classics today. Your 16:9 television was picked as a compromise between the classic movie format of 2.39:1 and the then 4:3 standard of TV. The idea being that there would be bars on each type of content but the bars would average out to being smaller than if other sizes were used. TV pretty quickly matched the new screen size, and some movies followed, while other movies are still shot in the older wide formats. In both 4:3 and 16:9 television formats, movies can be shown with black bars, or cropped to fit the narrower screen. Broadcasters make a choice based on what they believe their audience would prefer. | 10 |
8f4lvt | Biology | Why can't music damage the dopamine system in brain like drugs do? | In theory it could, but the sheer number of receptors being triggered etc is just massively different | 3 |
5yblxf | Other | What is the purpose of all the fake profiles on Tinder? | Gets people to use the paid survice, more "girls" in the area, more chances a guy will pay to get more swipes and vice versa(but not really). | 1 |
b877bu | Biology | If a kidney is deteriorating and doctors don't know what's causing the issue, can't the patient be put on a dialysis system indefinitely until the problem is found and solved? Is there a way to remove the organ that is struggling to keep up from the mechanism until the cure can be found? For instance, if an infection is shutting down the kidneys, can't they just take the kidneys out of the equation so that they don't continue to deteriorate? Solve the infection, cure the patient, then reintroduce the kidneys? | As someone on dialysis I can at least speak to the process. Even when you are on dialysis your kidneys are not "removed from the equation." Dialysis is performed from once a week up to six times a week. I myself perform dialysis five days a week for three hours a day. During treatment my blood is filtered and the toxins that would normally be removed by the kidneys are removed and disposed of. Additionally, as a function of the kidneys is to remove excess fluid the dialysis machine will also remove additional fluid from my blood to prevent fluid overload causing edema (swelling) and the issues related to it. Now the reason why your idea won't work. My kidneys are still connected to my circulatory system. Meaning, that although they are not really working blood is still passing through them. In my case I have around 8% of my kidney function left. That means that my kidneys are still filtering out some fluid and a very small amount of the toxins. I still produce urine. Which is not the case for all dialysis patients. Although as they say, it is not "good" urine. Dialysis is not a kidney replacement. It is not performed continuously or is a bypass for the kidneys. It is a support for the kidneys and is done to help relieve the body of the toxins and fluids the kidneys can no longer remove on their own. The kidneys continue to function and remain "in the loop" even when the patient is receiving dialysis. So even on dialysis the damaged kidneys would continue to deteriorate from whatever condition is causing it. Although in some instances by allowing the kidneys to "work less" through dialysis the progression of the deterioration can be slowed down. | 1 |
7l57ap | Other | Does sign language provide the predominant message for hearing impaired people? Or does the lip reading do most of it and the signs are just there for context? EDIT: Who the fuck is downvoting this? | 1) Think for 2 seconds : lips reading would mean that you already know the language of that person. I you don't understand French and I speak French, what use will lips reading be ? 2) Sign language, as others have pointed out, is actually sign language**s**, BUT these languages have a lot in common, meaning that an American could have a conversation with a European in sign languages, without having to learn any of the European languages at all. This has actually happened to me, as I was working as a translator : I saw people from different countries who hadn't the slightest clue in other people's languages having conversations in sign languages, even having fun at noticing the slight differences between the signs used for this and that in each language. That was a pretty humbling experience, as I've been studying Japanese for more than 10 years and suddenly saw people who never did having fluent conversations with their deaf Japanese colleagues. A true WTF? moment. | 4 |
5q7910 | Other | What would happen if the US stopped giving aid to foreign countries? | The countries we aid would have more people die due to lack of food and medicine. At least they will if the slack is not taken up by other countries giving aid. | 1 |
gxoj2j | Mathematics | Uses of complex numbers. I recently got interested in the topic of complex numbers, I watched a few videos on YouTube about the subject and I think I got the general idea of what they are. But I still don't understand what uses they have in real life. | There's this step up from complex numbers called quaternions, where on top of i there's j and k as well, which are all square roots of minus one. The interesting part is there's now 3 imaginary numbers. Since there are 3 dimensions as well, these quaternions can be used to describe rotations in 3D space. Quaternions are widely used in games and other 3D applications because they are more reliable than Euler angles and prevent Gimbal lock. | 6 |
6c6zsk | Other | Why does eating spicy food make you sweat and make your eyes water? | The eyes watering thing and the sweat are actually caused by two different systems reacting to the same things in their own way. Spicy food usually contains Chili which contain a substance called capsaicin. Your eyes are watering and your nose is probably running because almost all humans are essentially allergic to capsaicin. So you get the same reaction you would get if you had something like a pollen allergy. Your body's immune system has tagged capsaicin as a threat, and is doing everything it can to flush it out of your eyes and your nose. You are sweating because your nerves are telling your body its hot, because capsaicin is essentially causing them to lie. You body has nerves called thermoreceptors. When it's hot, microscopic holes open up on the cell walls and let charged ions through, causing the cell to be come electrically charged and fire. Capsaicin gets stuck in those holes and jams them open, causing the cell to fire telling the body it's hot. So the body reacts by trying to cool itself. | 2 |
9mu8u2 | Biology | How Does Voluntary/Involuntary Breathing Work? | The trigger for involuntary breathing is a rising co2 level. The medulla can measure how acidic the blood is and triggers breathing. | 2 |
glkl63 | Physics | Are there points in space where any past event is observable? We can through telescopes, observe events from far distant locations. Is it also true that if you were able to travel to any location in space, that there would exist a location from which you could observe any past event, even up to the big bang? | Yes, here on Earth you can see past events, just go outside at night and look at the sky. The Moon you see has moved several feet by the time you observe the light that reflected from it's surface. The planets, which are more distant, have moved even more by the time you see them. The stars you see? They are all millions of miles from where you see them, and some may not even exist right now. You are seeing them as they were years, or even billions of years ago. Photons are time machines. They do not experience time. They travel unchanged by any event until they are destroyed or altered by contacting something, which in this case is your eyeball. In fact, you never see something as it is *now*, but only as it was when the photon from it hits your eye. | 3 |
jtk5ap | Technology | How can website detect that you are using a adblocker? | Adblock detection is done in couple of ways. The most common way is to look for elements that should be displayed and aren't (ads.js for example). Another way is to check if a CSS property has the value you expect it to have or check for hidden browser windows. | 2 |
6t8lbr | Mathematics | What are the practical uses of logarithms in real life ? | There are several measurement scales which are logarithmic in nature. The two most popular ones are the Richter scale and decibels. Each step in the Richter scale represents a 10x increase in power of the earthquake. So a 6.0 is ten times more powerful than a 5.0 which is ten times more powerful than a 4.0 (which means a 6.0 is one hundred times more powerful than a 4.0). Decibels are similar but the 10x happens every 10 steps. So 30 decibels is ten times more powerful than 20 which is ten times more powerful than 10. | 11 |
5t411m | Repost | Why is there a flu "season"? Also, do other viruses and bacteria have time frames during which they are more active? | It's cold outside. Everyone goes inside to be warmer, and to avoid hypothermia. Now you have many people concentrated in a small area. Germs now pass along easier. Viruses die quickly without a host but now they can find hosts easily. | 1 |
im3ccs | Technology | What or why do geiger counters make this "krkrkrkr" sound when measuring radiation. | Geiger counters are used to usually detect two things, beta particles and gamma rays. There is a tube in this apparatus which is filled with a special kind of gas. When a special type of particle hits this gas in the tube it can conduct electricity. The radiation can penetrate the tube and rubs with the gas, releasing electrons, if this happens enough there is enough electricity to flick a switch "krk". Lots of "krks" is lots of ionisation happening. | 3 |
o3s2i6 | Technology | If all noise cancelling headphones do is reverse the soundwaves coming into them in order to ‘cancel’ the background noise, why can’t they cancel a sine wave completely? | They can. But only at very specific spots and, since your ears capture sound over an area, they can't completely make you not hear it. If you have a pure sine wave signal (a pure tone) and broadcast the exact opposite, you will indeed cancel to exactly zero wherever the loudness (amplitude) and alignement (phase) of the reversed wave exactly opposes the incoming wave. Assuming that the cancelling signal is louder than the incoming signal, this will always happen \*somewhere\*. But it'll be a very small region. Your eardrum is a whole area so you can't cancel the incoming signal across your whole ear, so some will get through, so you'll always hear some of it. Edit:typo | 5 |
gg0xk7 | Technology | How can you dial the emergency numbers without a sim card? How does it work actually without network too ? | Well, it doesn't work without network. Its a regulatory requirement that if the phone can see or be seen by any cell network (of the same technology, GSM, 4G whatever) it HAS to always be able to make an emergency call. All cell phones have the potential to contact any network its compatible with - however the network simply ignores it unless it has a SIM card that proves the holder of that SIM has paid to use the network. I think emergency mode on phones also kills background apps and anything else to prioritize signal strength and battery life too, but I've been out of the field for a while, so not sure about that. I'd be interested to know though, if a SIMless phone was within coverage range of multiple compatible networks what the criteria for which it would use for an emergency call would be. Probably best signal strength. Would be curious to know what the handover between networks would be in that case. So there's a LPT for you. In your emergency go-bag or car emergency kit, keep your old phone w/o a SIM and a battery pack thing, you'll always be able to make an emergency call. | 1 |
82whcz | Biology | Where does the cerebral fluid go when they cut your skull open for neurosurgery? Not necessarily just for neurosurgery, I see a lot of beheading videos on r/watchpeopledie and I never see cerebral liquid leaking. What happens to it when our skull is cut open? | It pours out like the rest of you. It isn't very thick and there isn't a lot of it so it's not going to really show up or overpower the blood. It also isn't going to squirt out like blood because it isn't pumping through your body. | 3 |
7erp6m | Biology | How do small, isolated groups of people (like the people who live on small islands) maintain enough genetic diversity to avoid genetic defects in the long term, both in modern times and in antiquity? | They don't. These places typically do have higher risks of inherited genetic diseases. That said, inbreeding isn't instant madness, just a higher risk. | 9 |
9ifb2v | Chemistry | Why do things like bread and cheese go stale when exposed to air? There will always be air inside whatever you seal it with, so why does new air make things go stale? | Unpacked food will either be dried out and/or exposed to bacteria and bugs that makes it go bad. Packed food is either in a vacuum or a protective (non oxidating) gas to keep it from reacting in such ways. Source: worked in food retail | 1 |
izhsuc | Other | Why do we consider the western most region of Asia the “Middle East” | It’s a quirk of English language and time. At first “the East” was called “the Orient” and was as far as the current “Middle East.” Then European explorers went further east than the Orient. That became “the Far East” and what was once “the East” or “the Orient” became “the Middle East” because it wasn’t as far east as you could go anymore. Same thing in the USA with the “Midwest.” | 1 |
6ejdlf | Mathematics | the Golden Ratio / Fibonacci sequence. Are the "natural" patterns associated with this number simply selection bias or is the universe somehow guided / structured around them? If you watch any video on the Fibonacci sequence they typically show the pattern seemingly reoccurring in most aspects of the universe; From the structures of atoms, to our DNA, to snail shells and flowers all the way to spiral galaxies. Is there something to this or are we just finding things to fit the narrative? | As far as I can tell, the answer lies somewhere in the middle. There's a lot of mysticism around φ and the Fibonacci sequence and people are finding coincidences that fit the narrative. However, φ does often show up in nature. We seem to have an intuition that very simple interactions should result in simple and uninteresting patterns. However, that's only accurate in the context of everyday life. When the number of interacting things is large and/or they interact for a long time, they can produce intricate and beautiful patterns. For example, the interactions between atoms of a soap bubble cause it to take the exact shape that minimizes ratio of surface area to volume. And for evolution to occur, it's enough that organisms undergo random mutations and the best adapted ones have more offspring on average. This results in a slow but definite statistical trend towards better and better adaptation. Over thousands of generations, it can give rise to astounding complexity. While finding elegant patterns in the Universe can be surprising to our intuition, it's not unexpected philosophically. The math that people find profound is usually simple but has unexpected conclusions. We know from Occam's Razor that a priori, logically simpler hypotheses (and mathematically simpler relationships) are more likely. So the weird thing would be if we didn't find many profound mathematical relationships in nature! φ is actually pretty simple. It's the positive solution to x^2 = x + 1 and it's the ratio of lengths such that the ratio of the larger to the smaller one is equal to the ratio of their sum to the larger one. The reason that some plants follow this pattern is explained in [part 3 of Vi Hart's series on the topic]( URL_0 ). The short of it is that new leaves are created in the center at regular intervals and move outwards while repelling each other; a new leaf is repelled mainly by two previous ones, which results in an angle of approximately φ. The relation to the Fibonacci sequence is that the further you go in the sequence, the more the ratio of consecutive terms starts approaching φ. This is actually a property of any sequence defined by the relation aₙ = aₙ₋₁ + aₙ₋₂. You can start the sequence with any positive numbers. There's a nifty trick to find the ratio: pretend for a moment that the sequence consists of just consecutive powers of a number, call it q. Then q^n = q^n-1 + q^n-2 so q^2 = q + 1. This has two solutions; the positive one is (√5 + 1)/2, which equals φ. You can also do this for other sequences; for example, if you take a sequence defined by aₙ = aₙ₋₁ + 3 aₙ₋₂ + aₙ₋₃, the ratio you get is √2 + 1. Finding the non-recursive equation for the nth term of the sequence is possible but more involved. You can use a procedure from linear algebra called diagonalization. This answer is already getting long so I won't go into it. | 3 |
hal4t9 | Engineering | Installing new set of tires on car | You could, but it'd be a bad idea. The *wheel balance* is necessary because wheels aren't made perfect, as much as people try. Wheel balancing involves spinning the wheel and tire on a sensitive machine, then adding weights to correct the imbalances that exist. *Wheel alignment* refers to how the wheels are, well, aligned with respect to the arms on which they're mounted and the road. Because the alignment is done with the wheels on, every time you move wheels from one arm to another, it's recommended to realign them. Failure to align can result in faster tire wear, or a perceptibly bad ride. | 1 |
6eivmy | Biology | Is it possible for a person needing an organ transplant to obtain one from their own stem cells? Suppose a person is diagnosed very early on with some sort of disease that will eventually deteriorate an organ and requires a transplant. Is it possible if medical professionals can harvest some of the afflicted patient's stem cells and grow the specific organ for them? Would this eliminate the need for organ transplants from different donors? Will their body's immune system still reject the new organ even though they are from the host's body? | To piggy back this, suppose our own stem cells were stored from birth for our own personel use? | 3 |
cfwkdi | Technology | How did Super Mario Bros on the NES look blocky, have no detail, and lack a bunch of features; yet Super Mario Bros 3, also on the NES, with the same hardware, have a fully fledged world map, Siginificantly higher quality sprites, and more content? While on the same cartridge? | How do you become better at maths over time, despite the rules of math remaining the same, and you being the same person? You learn more. You work out faster ways to do the same thing. Programming is the same way. Also; the cartridges are unlikely to have been the same; as time moved on memory became cheaper and its much more likely that SMB3 had significantly more available memory than SMB1. Not to mention things like co-processors such as the later SuperFX chip for the SNES cartridges. | 6 |
eq9uhs | Engineering | How are dams/structures in contact with water maintained? How are structures that are constantly in contact with water repaired or maintained? I imagine there has to be some sort of preparation or specific process for this? | Concrete 100% submerged is significantly less susceptible to deterioration than concrete that goes through wet/dry cycles which would be in shallower depths. For shallow depth repair work, you can install temporary cofferdams around the work area to dewater the immediate area to complete the required work. Also divers can do many repairs, albeit slower/costlier in general. | 5 |
6fpumz | Biology | Why are animals, including people symmetrical? | Internally, we're not. You have paired organs, you have non paired organs, your great vessels are not symmetrical, the heart is on the left, having it on the right is not good for you, having your abdomen flipped as well is worse. While the lungs are paired they're different, with the right having 3 lobes and the left having an underdeveloped lobe. Your gut is a nonsymmetrical loop. | 2 |
dz860l | Biology | How come we don't get hurt when we throw up if our stomach is filled with acid? I know our stomachs have a special coating that protects it from it's own acid, but when we throw up the stomach's contents get ejected back from where it came from, passing through the esophagus and the mouth; how come these two don't get damaged when we vomit? | If you remember the last time you threw up because something actually made you sick as opposed to making yourself vomit, you would have noticed a few minutes of hyperdrooling thick slimy saliva that you probably spit out. That was to protect your mouth and teeth from the acid. | 4 |
muxzui | Technology | How do animators match a character's mouth animation to a voice actor's speech? | They mostly don't, it's been basically figured out that there is some pretty simple tricks to animating mouths. Like they match a small list of sounds so those match then people basically will ignore anything else. So you just make a round mouth on like "ooh" sounds then a few others then the rest is basically random lip flapping and no one really cares or notices. | 1 |
8wyre4 | Engineering | How do pilots know ahead of time when turbulance is going to occur? | Meteorological information can be used to predict turbulence with reasonable precision. Also, aircraft will report when encountering turbulence and air traffic control will relay that to other aircraft in the area. | 2 |
k3llo4 | Biology | If you could see DNA with the naked eye, what color would it be? | *Anything* roughly the size of the wavelength of visible light or smaller (roughly a micrometre or smaller) doesn't interact with visible light in the same way that large objects do. Anything this small essentially has no colour - it's really that it doesn't even make sense to talk about it having a colour in the sense we're used to. For an object smaller than the wavelength of light, you can't even *see* it using normal light - not even through the most powerful optical microscope. You need to use an electron microscope or something, which generates images using electrons instead of light. This is why electron microscope images are all greyscale (unless they've been artificially coloured). However if you get enough of something tiny together to make an aggregate size larger than about a micron, you can start to sensibly ask what colour it is. Then the colour will depend on the physical reflective and absorptive properties of the aggregate, just like large objects. | 3 |
8j5gds | Biology | What is the role/point of the interstitium in the body? | Every cell in your body needs to be able to exchange nutrients with your blood. However, it's obviously not very feasible for every cell to be able to directly exchange nutrients with blood since, by the nature of how the process works (diffusion), it is only effective over very short distances. So the interstitial fluid is where the exchange happens. Since all cells in your body are surrounded by interstitial fluid, blood can just dump oxygen into the interstitial fluid, which can be picked up by your cells. Your cells can also dump waste products into the interstitial fluid to be picked up by blood tl;dr easier exchange of stuff between intracellular fluid and plasma. | 1 |
6xd9i4 | Biology | Why do some people always feel tired after waking up (no matter how many hours they have slept), and others always wake up with a burst of energy? | I read your comments here about how many snooze alarms you set, and we might be related. I don't do it anymore, but when I used to have to be at work at 6, I would set an alarm for 4 to be awake at 5:15 I was constantly late because I had moved in with my wife (then GF) that year and she always turned it off instead of snoozing. She would see me sit up completely in bed and assume I was up and turn it off. I would be too exhausted to get up though and I was late like twice a month. It would have been more, but I didn't go in that early every day. I am much better now, but I HAVE to exercise. It doesn't matter if I gain weight, eat healthy or poorly, etc. I have to run every single day or I sleep like garbage. I also really only need 5-7 hours of sleep. If I sleep 8 or 9 hours, I get tired just like I used to do first thing. I do 6.5-7 hours of sleep when I can, I exercise, and it's MUCH better now. | 22 |
8dts2v | Biology | How dental health contributes to cardiac health. | Bacteria enter your bloodstream through your gums when you brush your teeth etc. Bacteria in the bloodstream cause 'inflammation' - lots of cells and chemicals that try to kill the bacteria. Inflammation in your bloodstream over a long time can increase the build up of fat in the walls of your blood vessels (pipes). The vessels get stiff which makes the blood pressure in them go up. High pressure damages the small vessels that go to places like your eyes and kidneys. It makes your heart work harder, so it has to grow, increasing it's chance of having a heart attack or an electrical failure. The important vessels in the heart and the brain get narrowed increasing the risk of heart attacks and strokes. If very bad bacteria get into your bloodsteam in quantities your body cant fight, they can latch onto your heart valves and destroy them. | 9 |
a4r2mk | Biology | What causes that 'gut feeling' that something is wrong? Is it completely psychological, or there is more to it? I've always found it bizarre that more often than not, said feeling of impending doom comes prior to an uncomfortable or dangerous situation. | URL_0 Some of it is instincts coming from senses you don't normally pay attention to in modern society. Like smelling aggressive pheromones on someone, or maybe aggressive body language that you cant put a label on, but 2 million years of primate instinct are telling you something's wrong. THis is the gut feeling, the old part of the brain screaming at you to pay attention, were about to get killed but we don't know why. Also, they have found that the gut has a massive nerve ganglion thing going on, almost a second brain, so it might literally be your gut telling you something. | 22 |
71mml1 | Biology | How is it that sperm and eggs can be frozen for years to be used later but we can't freeze a living person without killing them? | lets say 90% of cells survive this. for sperm and eggs this is not a problem, because you can use the 90% surviving cells. for persons this is a problem. it 10% of your biomass is dead, you will die. | 17 |
gx720y | Biology | If your skin regenerates over time, how does tanning or getting a sun burn when you’re young contribute to getting skin cancer when you’re older? | When your skin regenerates it is by cells dividing - basically copying themselves. If one cell gets damaged in a way that doesn't make it unable to copy itself it makes copies of itself with the same damage, so you go from one damaged cell to two, then 4 then 8 ect. If another little big of damage happens then the new copied cells have 2 damages on them. If enough of these little damages add up or damage happens at the correct spot then the cell becomes cancerous. UV light causes the little damages to the cells that can add up to causing cancer. Tanning is your bodies response to attempt to limit the amount of damage that can happen, sun burn is your body killing off damaged cells. Every time your body does that there is a chance that damaged cells can make it past the defenses and become cancerous. | 5 |
m0kvul | Physics | What’s with all the fire warnings on kids’ sleep clothes? Are they gonna roll themselves into starting a fire? *totally confused* | In the '50s there were hundreds of lawsuits over some Halloween costumes catching fire. This led to the 1953 Flammable Fabrics Act. | 5 |
c3sm34 | Chemistry | How does sunscreen/sunblock work? | Sunblock is a layer of liquid you apply to your skin to protect your self from UV-Rays. Basically there is a type of radiation emitted by the sun called Ultraviolet, which is very damaging to humans and living organisms because it causes damage to our DNA. Sunblock and sunscreen puts a layer that is capable of absorbing the UV and therefore protects us. Here is a video of how sunblock looks in UV camera, notice how the layer added looks pure black, because it means ALL the UV is absorbed (or most of it) by the sunblock and protects your precious skin. Video of application in UV camera: [ URL_0 ]( URL_0 ) | 2 |
90rkw9 | Chemistry | How does fruit get sweeter as it ripens on my counter? One week it is bland and tart and the next it is rich and sweet with seemingly no outside influence. How do? | The fruit break down the starch is it to sugar so it taste sweater. Starch and other carbohydrate is food is long chains of sugar molecules connected together. Even cellulose tat wood is made of is long chains of sugar. | 1 |
eh0n9a | Biology | Why are men’s marathon runners legs so skinny but female marathon runners legs are so thick? | Women naturally carry more weight in their thighs and hips than men. Therefore most non-elite marathon female runners will be carrying their excess weight there vs. men who tend to carry it in their gut and upper body. But at the world class elite level, both men and women are essentially twigs in their legs along with the rest of their bodies. | 3 |
6skul6 | Mathematics | If the economist predicts a growth of 3% but it comes to be 4% in reality, was the economist off by 25% or 33%? | ...Did you just ask us a simple math question in a story problem? | 25 |
8mkvwb | Culture | why indigenous ancestry is a source of pride in the US, but a source of shame in Latin America? | I can't speak for America but in Canada it was always a source of shame. Something people hid. Education would be the major change. The country started teach about their part in our history it was celebrated more and more. Now people are proud of the rich shared history. | 3 |
ggvi9i | Biology | What makes you lose the "sleepiness" when you have to get up to get some water or turn off the lights? | When you wake up, your body goes through several physiological changes, mostly due to hormone secretions. When you sleep, melatonin levels are high (between 12 and 8am in most people) and makes you sleepy. Melatonin is inhibited by exposure to light, which is why limiting my screen time before bed helps you fall asleep better. Typically, shortly before you wake up, your anterior pituitary gland secretes a hormone called ACTH or adrenocorticotropic hormone. This travels to your adrenal glands near your kidneys, and makes them secrete hormones like cortisol that brings your body from a sleeping state to a more alert state by increasing your metabolism. Another hormone change is aldosterone, which plays a role in how your body handles sodium and potassium, and by extension causes water retention. This is what allows you to normally not need to pee at night. If the levels of aldosterone are too low at night, you will produce more urine and your bladder will fill, making you wake up. The levels of aldosterone drop when you wake up to allow water to leave your blood stream again and be made into urine. When you wake up at night to go to the bathroom, your body secretes hormones to help you be awake enough to function. Those hormones must now be eliminated from your bloodstream before you can sleep again. Luckily there is some leftover melatonin after you go to the bathroom which allows you to go back to sleep once the cortisol has gone. Edit: you go to the bathroom, not the bloodstream Second edit: pituitary not pineal | 3 |
6uimc7 | Engineering | Why does a smart phone touch screen work after the glass has been broken? | The glass is separate from the digitizer piece. Digitizer is it's own clear plastic panel under the glass. | 2 |
8ivu8b | Culture | Why is a lion seen repeatedly in British, specifically English Imagery? A lion can be seen in their league and national football team badges, as statues in Trafalgar Square and a lion is even found in one of the names of a former king of England (Richard the Lion Heart). | There were European Lions as well. I believe they were called cave lions. Different than African lions and now extinct. | 3 |
6rzvk9 | Economics | How was 8 hours/day determined to be a regular work day? | 24 hour day. 8 hours to work. 8 hours to sleep. 8 hours to live your life. Businesses gave in on the 8 hour day and weekends off on Henry Fords lead. He wanted his workers to have the time to spend the money they earned. Unions fought for it, but businesses gave in because they saw a way to benefit from it. | 12 |
k208s4 | Technology | What does the printer do when it goes chrrrzh-gurhh-mbeerrch-beep-boop scrchraaaa | The initial sounds might also come from self calibration and homing of all the moving parts. Basically the printer is rather dumb, it doesn't really know where each part is (like the ink carriage etc) so to start each time with a known configuration it performs routines to move the parts until it reaches hardware limits (either micro switches or optical sensors). | 7 |
7rbmcl | Physics | Why didn't this bottle of water freeze? | It's possible there wasn't enough room for it to expand in to. When water freezes, the air in it is basically separated which causes it to expand, and if there's no room for it to expand, it would require greater force (in this case, cold) to make it happen (and would then break out of the bottle). I'm honestly surprised it didn't freeze. | 5 |
l7ckr5 | Economics | Stock Market Megathread There's a lot going on in the stock market this week and both ELI5 and Reddit in general are inundated with questions about it. This is an opportunity to ask for explanations for concepts related to the stock market. All other questions related to the stock market will be removed and users directed here. How does buying and selling stocks work? What is short selling? What is a short squeeze? What is stock manipulation? [What is a hedge fund?]( URL_0 ) What other questions about the stock market do you have? In this thread, top-level comments (direct replies to this topic) are allowed to be questions related to these topics as well as explanations. Remember to follow all other rules, and discussions unrelated to these topics will be removed. **Please refrain as much as possible from speculating on recent and current events.** By all means, talk about what has happened, but this is not the place to talk about what will happen next, speculate about whether stocks will rise or fall, whether someone broke any particular law, and what the legal ramifications will be. Explanations should be restricted to an objective look at the mechanics behind the stock market. EDIT: It should go without saying (but we'll say it anyway) that any trading you do in stocks is at your own risk. **ELI5 is not the appropriate place to ask for or provide advice on stock buy, selling, or trading.** | At what stage do the hedge funds actually lose money? Can’t they all just ride it out and wait for the bubble to burst and stock prices return to normal? | 489 |
6gjsse | Other | Orange Harvest Moons ELI5: Why is a harvest moon orange? Is it something with the earth's atmosphere that gives it the orange tint? | First of all, the harvest moon is just the name of the full moon closest to the autumnal equinox. It's no more orange than any other full moon on average. As to why the moon is sometimes orange, yes, it's the atmosphere. It's the same reason the sunset is orange. When the moon is near the horizon, there's more air in the way to scatter the blue light away, leaving the red and orange light to get to your eyes. | 1 |
758f9p | Biology | why do your gums bleed if you don’t floss for awhile, but they’ll stop bleeding if you floss regularly? | It's a combination of things - and not all of them will be true for every individual. Firstly, people who don't floss have a higher incidence of gum disease. This can lead to the gums becoming inflamed and they will bleed when brushed or when eating. This is the most common cause of bleeding gums, and it can be at least partially treated by flossing, which removes food particles and tartar from between the teeth, reducing the likelihood of infection and allowing the gums to repair themselves. Secondly, flossing "toughens" the gums through repeated physical stimulation of the tissue. This results in the gums becoming firmer, and closer to the teeth, reducing the likelihood of bleeding or infection. There's a growing body of research that suggests flossing is in fact not as amazing as most dentists claim - interdental brushes are likely far more effective, and are actually easier to use. | 1 |
7wt4yo | Physics | Why Do dancers’ ribbons follow a pattern they trace rather than just being pulled along in the direction of travel? [This is what inspired my question]( URL_0 ). Why does the ribbon follow out the pattern she draws? Especially noticeable is the tight turn in the last few frames. | The ribbon follows the path due to conservation of momentum, which is a physical quantity that relates to velocity (I.e. it depends on where and how fast you're going). As I mentioned above, physical laws tell us that this quantity has to be conserved. This is for example why you are being pushed to one side of your car, rather than immediately changing direction when you're driving trough a curve. The momentum you had before entering the curve keeps you going in the initial direction until you are stopped by, say, your seatbelt. Now, switch the car in the analogy with the ribbon of the dancer and imagine what happens when she flicks her wrist. The ribbon is just like the body in your car that wants to travel in it's initial direction. | 3 |
j6ji7u | Other | why do different accents exist from different parts of the world? Not only from countries far apart, but even different states in the US? | Languages change. Pronunciations shift, grammar and vocabulary change (consider: when was the first time you heard the word “extra” used in the form “that was so extra of him”?), and any attempts to artificially keep a language stable are doomed to failure. And when languages change, they change differently in different places. A community in Ohio might start adding ‘r’ sounds to words like “wash” (my Ohian father pronounces it “worsh.”) People in California might start shifting their vowels to start further front in their mouths. Gradually, these changes build up until you have regional accents. | 2 |
b0208i | Biology | When you eat citrus or anything that strips away the enamel on teeth, your teeth get sensitive. I learned that enamel does not grow back, so how is it that over time your teeth are no longer sensitive? | Your teeth are filled with these tube like canals, when those canals are open your teeth are sensitive but over time those canals close (or with the help of sensitivity toothpastes they close) no longer causing the sensitivity | 2 |
n99tpx | Other | On long drives when you realize you were completely zoned out from point A to B, are we aware of what's going even though you're zone out ? | This is known as [highway hypnosis]( URL_0 ). Let's say you have a journal where you write down important events. One of the days, you didn't write down anything for a lunch period because nothing major happened. Without that entry, you can't remember what you ate but you don't feel hungry. You obviously didn't choke on your food or forgot how to breathe so you were functioning normally. The same thing happens when driving sometimes. Your body is alert during those driving times but because there were no notable events, it doesn't record that time period into memory. When you try thinking back to it, you can't recall it since the information was not saved. | 4 |
kuf15n | Other | What is dropshopping and why instagram kids boasting about million-dollar sales? | The general way retail works is that retailer buys products from a manufacturer or distributor to mark up and sell. This means needing money or credit to buy inventory to sell. Drop shipping is taking an order for a product and then paying the manufacturer or distributor to ship it directly to the end customer, meaning it bypasses your possession, warehousing, and you collect payment for item before paying for the product. But it’s hard to do successfully, particularly as a small operator, so it’s more get rich quick scheme than real business opportunity. But it can be used successfully by larger businesses for certain types of items, like furniture where it’s more cost effective to only ship from factory to final retail customer, or as a way to offer more product/deeper catalog than is practical for a business to keep in inventory (say an auto parts store wanting to sell parts for classic cars). | 4 |
7hnl67 | Physics | Why do balloons heat up when stretched and cool down when relaxed again? For example, if you hold a balloon against a part of your body sensitive to heat (I use my upper lip) and stretch it, you can feel heat, and when you let it compress again it rapidly cools. | Its origin is in entropy. [Entropy]( URL_0 ) is a measurement of disorder. Now consider that a rubber is composed of a bunch of polymer strands (looking like a bowl of cooked spaghetti). When stretched the polymer strands should be more aligned and straighten out along the direction of the stretching. So when you relax it the strands go in all directions, or become more disordered. Entropy is related to heat, and during relaxation the entropy is increased. So if the system (aka balloon) heat is positive, heat must go into the strands of polymer. If the heat goes into the rubber, where does it come from? The heat comes from the environment - the balloon feels cold. [Source.]( URL_1 ) And when you stretch it, the reverse thing happens. | 2 |
aaaxf3 | Economics | How do Buffet restaurants make money? | [ URL_0 ]( URL_0 ) Actually answering OP's question, the wholesale cost of food is actually really really cheap. In most restaurants, food cost runs 20-30% of total costs. Buffets cut back on most of the other variable costs. | 19 |
77i5gl | Repost | Why do beverages taste different in cans than they do in plastic or glass bottles? | Probably not what you're looking for, but I know that plastic bottles don't hold carbonation as well because of the way the molecules bond together compared to glass or aluminum cans. | 1 |
6gckvl | Culture | Where did some of the more common anime tropes, such as naming attacks or having blood shoot out of a person's nose to show arousal, originate and how did they develop over time? | I'm gonna piggy back on this and ask a few: The trope that individuals gives solemn or dramatic lines while having their back back face their audience. In western culture we face our audience and look them in the eyes when talking to them. In anime, a character (usually a badass, a villain, or a father-figure) says a plot reveal while their back is facing the hero or cast, followed by usually disappearing or walking away once the punchline is delivered). The trope that androgenous males with thin and waifish builds are extremely powerful and only need to use the slightest, most effortless motions to employ extremely destructive or precise and deadly attacks (Kurama, Griffith, etc). As opposed to the trope in western culture of big brawny muscular guys being strong and powerful and waifish men being weak and poor fighters. *Does this have any basis in Japanese culture of Samurai not being muscular and brawny but being highly technical and precise in their swordsmanship, also perhaps roots in Zen Buddhism to go with the flow//Water Scroll from Musashi? Perhaps a notion in Japanese culture that raw strength is barbaric/gortesque, and elegant and refined technique and aesthetics are better marks of a finer warrior?* | 39 |
cw9tuf | Other | Why is underwear "a pair"? | I know it’s not exactly related but.. Nordstrom will sell a single shoe of any kind, even designer, at half the price for amputees. A consolation I know but I find it kind of cool. | 13 |