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How do fruit flies start?	There's a very famous experiment where the scientist took two jars with meat and put a cloth over one but left exposed the other. Guess which one got flies - NOT the one with the cover. The flies are attracted to it even before it decays. They lay their eggs, which you don't see, and they later hatch. Only then do you see the flies. By the way, those disposable bags that attract flies really do work. I threw out about 2 POUNDS of flies the other day. it was the most disgusting thing I ever saw.I 've asked this question, but about wine, for years. Like "where WERE YOU, before I left out that finished bottle of merlot a few hours ago."
Why do human teeth get infected and die off so easily?	I also experienced tooth decay and I will give you advice. Teeth are physical structures, not chemical structures. Therefore, unlike other body organs, it is very simple to manage and if teeth are well managed, teeth are preserved until you are 70 years old.And conversely, because it is not a chemical structure, it can not be recovered unless management is done properly. 1. Please drink sugar free coffee instead of sugary coffeeSugar is the biggest factor in eroding your teeth. 2. And you should brush your teeth before you go to bed. Teeth are most likely to corrode while sleeping. Especially after drinking alcohol, you should not go to bed without brushing. 3. If you eat something, please brush your teeth immediately. When this becomes habitual, the teeth never rot. Until now, you didn't brush your teeth habitually, your teeth will already have a lot of corruption. But from now on, if you habitually brush your teeth, you can prevent any further tooth decay. The lifespan of your teeth depends entirely on your lifestyle.I also experienced tooth decay in my teens, but after living with the above things, I have not suffered tooth decay anymore.
why is rainbow curved?	A raindrop can refract light and, the same way a prism does, break the white light into the colors of the spectrum. A prism doesn't create a curved display though, because it's only one object doing the refracting. With the sun at your back and you see it shining on falling raindrops there are huge numbers of droplets refracting in every direction. Think of a rainbow as a graph of all of those raindrops that are in a position to refract the light in your direction, those that are 30 degrees away from the shadow of your point of view. When you and a friend are looking at a rainbow you are both seeing your own personal version of the rainbow.
Why does gold run in veins? All heavy metals like this come from supernovas. Why would they concentrate in some position when they eventually make it to Earth?	As I understand it, at a given heat and temperature, minerals become dissolved/melted and as they flow cool and condense at certain points and you wind up with concentrations. Gold may be a little more involved, since it's fairly inert, but this is how you get veins of crystals and the like.
If lightning is drawn to metal and the tallest objects in a given area, why doesn’t it always strike airplanes?	Even though there are around 9000 aircraft in the skies at any one time, that's still not many compared to the surface area of the planet, so thunderstorms do not often get the chance to zap one - as someone else has already posted, aircraft also tend to avoid thunderstorms if they have any option. They do get hit though - I know this from personal experience. A plane I was on took a lightning strike and I can confirm that it makes a loud bang, followed by a couple of nervous screams from passengers!
Why do fans make rooms colder? Wouldn’t faster moving air molecules make a room warmer?	Fans don't make rooms colder, they just blast you with air, that gives you this sensation. Its like when you put your hand outside of a really fast moving car, despite the temperature it always feels chilly.The same reason you can blow on a cup of hot soup to cool it off & #x200B; & #x200B; & #x200B; MAGIC
Why is it rude to ask how much someone’s salary is?	Humans are greedy, envious, prideful creatures. They want more than the person next to them and will do stupid, and sometimes hurtful things to each other just to be better off than their neighbors. If person A finds out person B gets paid more, person A will make it their goal to be paid at least the same as person B, and may act out trying to achieve said goal. On the otherhand, if person B finds they are paid more, they may think themselves better than person A and try and rub it in. This developed into a don't ask don't tell mentality so the problem doesn't occur. TLDR, humans being shitty to other humans made a social stigma
Why do modern cinemas still use projectors?	They don't still use film projectors. They use digital projectors. Projectors are necessary because a screen big enough for a movie theater would be insanely expensive.
What is intermittent fasting? I've been seeing posts describing they lost a ton of weight by doing it, can anyone explain?	It's just another way to try and limit your calorie intake. That's really all weight loss boils down to calories in versus calories expended. If you're using more than you're putting in, you will lose weight. Making it so there are times you're strictly prevented from eating, as long as you stick to it, generally translates to an overall decrease in your calories. Which for most people would mean you'll lose weight.
Why do railway tracks have stones around?	I didn't see any other responses mention ease of maintenance, so I guess I'll chime in. One of the main factors limiting the travel speed of trains is the dimensional consistency of the tracks. By using a very stable material like stone, the dimensional stability of the track bed is increased, as others have said, because water can drain and there will be less heaving in cold climates. In addition to this important aspect, the use of stone allows the geometries of the tracks to be maintained over time with tampers. These machines can quickly return tracks to their original shape by using vibratory tines to reset the stone under the track sleepers. They are pretty exotic machines if you like specialized mechanical equipment. [Here is a video of one in action]
How do anti-tank weapons kill tank crews after penetrating armor?	At least for WW2, survivability was largely a function of being able to get out before the stored ammunition caught fire. Fuel fires were kind of whatever, you have extinguisher systems and it's also mostly on the other side of a bulkhead from the crew. But ammo was generally stored in the open with the crew. And it burns extremely hot and very fast. For a typical five crew tank, you're probably looking at 1-2 casualties per KOed tank, about 75% of which are wounded and the rest dead. If you have enough well designed hatches and the ammo doesn't ignite, you're on the low end, and it's basically whoever's closest to the hit being hurt or killed and everyone else getting out. Assuming you get hit where the crew are, i.e. a hit through the side to the engine probably leaves the crew intact. At least, for that one shot. They don't get a kill announcement like an FPS, they'll shoot until your tank catches fire or changes shape . There's a famous piece of footage of an American M26 Pershing killing a Panther near the Cologne Cathedral, which shows most of this, including how quickly the ammo can ignite. Modern tanks generally have the ammo stored more separate from the crew. Example, current US Abrams stores it in the turret rear behind armored doors, while the roof is designed to blow off if it catches fire.Tankers die from spalling and/or heat. & #x200B; If the tank is hit anywhere in the crew compartment, survivability of the crew is essentially zero.
How modern tanks are said to be indestructible against WW2 era tanks?	Same way you can't destroy a ww2 take with a bb gun. The armor is too strong to penetrate with ww2 Era ordinance. Honestly, you could either sit far enough away and kill a ww2 tank before they even know you're there, or drive circles around them faster than the turret can turn.
Why sometimes when you take a short nap for a half hour that it sometimes feels like you've been asleep for days?	You nap less times than you actually sleep. So you're used to be asleep for way longer than half an hour. When you wake up there is no way to know how much you have slept until you look at the time. So whenever you wake up and there is no clear sign of what time it is you automatically assume you've slept for a long time.Sleep cycles are cool and all but real reason is you didnt get enough oxygen, open a window, make sure you dont have nasal congestion, clean the room etc. All things to make you breathe betterLookup the app Sleepytime, I use it religiously as I have insomnia, so when I fall asleep is based on when I take medication and timing.
Why is it bad to "blank" fire a bow? to release the string with no arrow in it.	When you pull back the string, the actual bow frame, or the pulley system on a compound bow has an incredible amount of potential energy building up. By releasing the string, the bow snaps back to its original at rest position. All of that built up energy is imparted on the string. In a normal situating, the string then imparts all of the energy into the arrow, sending it rapidly towards its target. When you dry fire the bow, all of that energy is released, but the bow has no where to send the energy and has to absorb it all. It can snap the string, or more likely, the frame absorbs the energy, and it doesn't do it well. It can crack or even shatter a bow frame.
How do we know the verbal pronunciations of words and phrases from dead languages?	Just because a language is dead now doesn't mean it was always dead. Back when it was not dead, there was a valuable niche in being able to speak it. This often led to folks writing down relationships to sounds as well an word translations between the language and others of the period. It may take a few steps, but it's possible to work backwards to a fair approximation. The largest problems are languages without a written form, like Navajo, which was almost eliminated in only a couple of centuries.
Why does the USA have so many nuclear power plants, despite only producing 9.6% of its electricity from nuclear?	Where did you get the 9.6% figure? For the past few decades nuclear power has produced around 20% of America's electricity. According to [the U.S. Energy Information Administration] it is currently 19.7%.In Canada we have a lot of hydro power. We make the electricity and put it on the grid for everyone to use. The grid also includes the US. The US makes power as well for the grid. The US can’t shut down their nuclear power during times when electricity isn’t being used and sells the unused electricity to Canada at a discounted rate. Canada then sells the power back to the US during peak times at an inflated rateYou also need to take a look at the generating capacity of each of those plants. They could be rated at a higher wattage between the two nationsThe entirety of the country of France is 67 million people. The population of California is 39.75 million. The population of Texas is 29.1 million people. Texas has two nuclear plants with four total reactors, and California has one plant with two reactors. Three reactors for a population equal to that of the entire nation of France.Your numbers are off. The US gets 19.7% of it's electricity from nuclear, not 9.6%. As to why France gets more of its energy from nuclear with less reactors, as other people have mentioned, France has significantly less people, so it has more reactors and nuclear energy generation per capita.
What determines the center of the world map?	There are Chinese centered maps from ancient China and Mediterranean centered from ancient Rome. Many old maps didn't have North or south either, as they used stars instead to ubicate. At the end of the day, Europe got powerful and we use the maps used by them. And we use those old maps with Europe being the westest part, and something called India and China somewhere far on the east of Eurasia.
Why are triangles the most stable shape in construction/engineering?	I'll start with a square. If a square is made from four boards and every corner is a hinge like your elbow, there is a problem. This shape can easily be squished out of shape. Your square can easily be changed into a parallelagram, A triangle cannot. A triangle is said to be inherently rigid because of this. It's natural, and so we see it all around us. Sidenote: triangles can't be bent. Moving any vertex it will always spin around an axis. That's really useful in 3d modelling.
How do poems written in foreign languages still rhyme after translation? Is the rhyming kept at the expense of original meaning?	When translating poems you essentially have to choose between preserving the exact meaning of the poem or the exact structure of the poem: if you translate the words as faithfully as possible the rhymes and metre of the poem will most likely suffer. If you preserve the structure of the poem you're going to have to choose new words that fit that structure, and that alters the meaning. the job of a good translator is to strike as good of a balance as they can, trying to preserve the structure while disturbing the meaning as little as possible. You quickly learn that you can't translate word for word, so you're going to have to understand and capture the intended intent and meaning of the poem and recreate it.Sometimes the initial language and the translated one both have roots in Latin which means that some of the words in each language closely resemble each other including possibly rhyming.
How were 2 countries able to discover and build nuclear weapons from scratch, simultaneously during the 1940s but most countries today can't build them without decades of effort?	Building nukes is not actually all that technically difficult when you know the basics of how it is done. Almost any developed country could build their own nuke if they wanted too. The problem is that it would hard to do so without tipping anyone of and the countries who already have nukes don't want anyone else to join the club and that the people in many countries might not support such an endeavour. If you look at for example Japan and Germany, there is little doubt that they could have a working nuke in relatively short time based on the technical challenge alone. However there would be huge resistance to the idea from both the people in those countries as well as the rest of the world if they tried. Building the sort of infrastructure that gets you the raw materials to make a bomb with is hard to hide and for the most part dependent on imports. Considering their limited usefulness for anything other than acting as a threat or starting a nuclear war they simply aren't worth the trouble form most countries at this point. You can be sure however that if one of the major current nuclear powers started actually using nukes on anyone. The number of nuclear powers would shoot up within very short order after that.
Why does it take 24 hours for muscles to start hurting after a workout? Why not straight away?	Animals whose muscles ache the day after running for their lives don't have to stop running as a result of muscle aches, especially when they need to run for their lives.
Why is it common amongst animals to give multiple births but not in humans?	Humans are really bad at giving birth, even compared to other apes. Turning our posture permanently upright required narrower, oddly angled hips, while developing sapience required big brains . Our babies are born undercooked as a result, remaining helpless for far longer than other newborns, and they're still barely able to fit through the birth canal without killing the mother.
If we have the ability to cultivate and grow our own food as well as being able to create it in laboratories, why is world hunger still a problem?	World hunger is an economic problem, not a production problem. Rich areas have excess food. Poor areas lack. Rich areas have limited motivation to give away and ship food , and poor areas can't afford the tech for massive production.
Why do all the other rocky planets in photos look covered in craters from meteors, yet earth doesn’t seem to have any?	I just compeleted a degree in Earth Science and have some insight. I am seeing a lot of answers talking about how our atmosphere protects us from asteroids. While this is true it is not the main reason we don't have large craters on Earth. The key reason is actually plate tectonics and erosion. In the beginning of the solar system there were A LOT more asteroids and a shit ton hit the Earth, the Moon and every other planet. The reason craters aren't here anymore is because our crust where these craters are in is constantly being subducted into the mantle and renewed fresh. The moon and plants like Mars are too small and now too cool to have plate tectonics so the craters on the moon are billions of years old where the crust of the earth is almost entirely less than 200 million years old.There are a few craters, although you’d have to zoom in decently far to see them. Most of the asteroids that would have formed these craters burned up upon entry into Earths atmosphere. Even if a decent size crater were to form, it would eventually get weathered away over millions of years. Earths oceans have also been struck by asteroids but left no craterThe atmosphere surrounding earth does a very good job at either breaking apart large objects falling into earth, or even bouncing them back into space, depending upon the angle they enter our atmosphere. The other planets dont have atmospheres. That said, there are large meteor craters on our planet, most are just covered in waterLook to Arizona if you want to see one. Otherwise the earths atmosphere protects us from most impacts.
why are solar-powered cars not a thing? think of the battery recharge on a sunny day sitting in rush hour!	They are a thing, it's just not really viable unless you live in southern California or a place with a similar climate.
Why are there “acquired tastes”? Why do some things, like beer, whiskey, and food delicacies take a few tries to become palatable?	We rely more on primal defences when we are children. Intense, bitter, or weird flavours cause a knee-jerk reaction that the food could be bad or dangerous. As adults we have the cognitive ability to override our initial reactions to something, we have more experience and can make positive associations towards certain kinds of pain or displeasure. We also can assign contextual desirability towards things that in another context could be considered gross or undesirable. That being said, we sometimes underestimate children and so don't even try giving them certain foods ensuring their food aversions. My friend gave his toddler everything from a young age, the four year old now even likes black olives and sardines.
Why do medications for mood/depression (Zoloft, Celexa, etc) take weeks to "kick in"?	Part of it is because we tell people it will take weeks to kick in. If we didn't, then a substantial amount of patients would feel a difference straight away. On a side note, have you ever seen the actual efficacy of anti-depressants? They are barely better than a placebo. To the extent they work at all no one really knows how. Same is true for ADHD drugs, based on subjective responses they are very effective, based on objective measures they are not.
Why is the current weather in Europe much more dangerous (at least as reported in the news) compared to other locations at similar latitudes?	High humidity . Houses built with large thermal mass Lack of exposure to high heat . Lack of AC, because we don't usually have to deal with fatal temperatures.
why would the death penalty cost more per year than a system of life (in prison) without possibility of parole?	The death penalty itself isn't all that expensive. But the amount of court appeals leading up to it are typically costly and lengthy.In the US death penalty cases have mandatory appeals. Because the states have a very bad history with unjust application of the death penalty the courts have imposed upon them a system of mandatory appeals in capital cases. This system helps prevent bad trials from resulting in executions, and it is very expensive. Significantly more expensive than simply housing a prisoner for the rest of his life.
Why is the air cold when you fan yourself on a very hot day? Doesn't motion generate heat?	It blows away the warm air that you'r body heats up.After that you' sweat can evaporate again which drains heat from you'r body.
Tablet screens vs E-Reader screens	It's e-ink, or electric ink. Imagine a tiny magnetic ball painted half white, half black. It will rotate according to the magnetic field around it, showing either its white face up, or black face up. Put thousands of them together, you have e-ink. Now you can imagine why backlight is not necessary.
what's the difference between gas grades, i.e. 87, 88 "the new standard" and flex fuel?	88 octane won't do any harm, but it won't gain you anything either. Read the owner's manual, if it says flex fuel is ok, then you can use that. Expect worse mileage on E85 gas though.
Why don’t law enforcement officers use tranquilizer guns to subdue perpetrators?	Because they don't work fast enough. When someone is charging you with a knife, you can't wait 20 seconds for drugs to take effect.Knocking people out chemically without killing them is [difficult. ] Weight, age, preexisting conditions etc make it extremely dangerous to try a one size fits all approach. There is a reason anaesthetist is a profession I think it all comes down to dosage. There would be one that would kill a perp if he weighed say 150 pounds and do almost nothing to the guy that weighs 250.
Why do nuclear reactors rely on diesel generators in emergencies?	> Is there a reason that power generated by normal operation can't be stored for emergency use? In a large scale battery or something like that? It can be, that gets you through a couple days. What do you do when you need to keep the coolant pumping for weeks or months? Its impractical to build a big enough battery bank, you'd need warehouses of batteries that are useless for normal operation. Diesel generators are cheap, powerful, space efficient, and work indefinitely as long as you keep pouring diesel and oil in the top. You can even have a couple extra one's that you rotate in so you can perform maintenance on the others. They'll be incredibly reliable and reasonable sized. Remember that almost all nuclear power plants in the world were built before Lithium Ion batteries were remotely common so all the backup storage would be with lead acid batteries. If you need 10,000 liters of diesel to power the generators until the problem is fixed then you'd need 70,000 liters or 2,700 tons of lead acid batteries to get you through the same outage. Its just not remotely practical for an outage where you might need 1,000,000 liters of diesel to cool the core all the way to a safe level
If gravity can bend light and distort images, why isn't earth's (and other planets) images distorted when we look at them through a telescope?	[This is how] gravity distorts images, and you need A LOT of gravity to really see the effect in a telescope. Otherwise, defects in the lens / mirror of the telescope, and the shimmering of the atmosphere, distort images MUCH more than what Earth's gravity does. This is why space telescopes have much clearer images than ground telescopes, even though their lenses and mirrors are much are smaller.Gravity has many interesting properties, but it is a very, very weak force. It causes tiny distortions,which can be detected in some geometries, but only with specialized instruments.
I've always heard that not eating breakfast is bad for you, but what are the actual consequences if you skip breakfast?	The consequences depend on your physical state and what you are doing. If you're an office worker in normal health, the worst consequence would probably be you getting hangry or overeating at lunch. If you're a diabetic who is taking medication when you wake up, not eating then could result in dangerously low blood sugar. If you're an endurance athlete and you skip breakfast, you may risk bonking or otherwise having a non-productive workout session.
Why are there so many sign languages?	> It would just seem to make more sense if there was one universal sign language. Well yes, but you could say the same thing about spoken languages. Signed languages are no different. So the reason that signed languages haven't coalesced into a single language is the same reason that spoken or written languages haven't.The short answer is yes, they are connected to specific languages. Each verbal language will.vary because the culture and location have different words, expressions, etc. Sign language reflects the local language, usually. ASL has roots in French, most ASL signs from original ASL are actually French signsAmerican Sign Language is actually closely tied to French. There are so many signed languages for the same reason there are so many spoken ones.
How does instinct work? How does an organism know how to do something without learning it from something else?	I probably shouldn't be saying anything on this subject because I am not educated in the area but Its not really known. They are starting to theorize that DNA might store some type of memories. Like I said its above my head I am just rambling BS that I have heard from others.
Why do people usually have to fast before an operation, and how does this work in case of an urgent, unplanned operation where the person has not been fasting?	Has to do with the sedatives the patient is given to knock them out/ keep them unconscious. Food in the digestive system can make the patient vomit or need to eliminate upon coming to. This is an especially bad thing if the operation is near an area where muscles violently contract . Also reduces the risk of rupturing digestive system and having partially or wholly digested material where it doesn't belong in the body. There are bacteria in your gut that you would die if they weren't there, but will make you seriously ill or kill you if they manage to get anywhere else in the body.
How did the United States historically handle previous mass migrations into the country?	There is no blanket answer here, as the US has handled immigration differently over the course of its history. One of the most famous periods was between the 1890's and 1950's. In this time period, immigrants took a boat to Staten Island, were checked for diseases, then disembarked. Passengers underwent an interview , had their belongings checked for contraband or taxable goods, then sent to Ellis Island. On Ellis Island, they had another medical exam, another interview , then sent on your way. Only about 10% were detained for various reasons and only 2% were denied entry altogether. Barring these cases, the process only took a few hours.Following high levels of migration around the turn of the century , congress passed the [1921 Emergency Quota Act] that restricted immigration from to any nation to 3% of their in the US population as of the 1910 census. At that time there was relatively little immigration from Latin America, and significantly more from Europe, which meant it was much harder to slip across the border or overstay a temporary visa . [Shortly after] the quotas were reduced to 2%, and Asian immigration restrictions got even more stringent.Historically speaking, almost everyone in the USA is either a migrant or some great grandson of a migrant. The Europeans travelled to America, after Columbus discovered it, and captured the whole land. It was either one of the following two: 1. Give the land and all's good.2. Natives die.
if a nuclear war would produce an ecological catastrophe, why hasn't nuclear tests produced it yet?	Many of these were done either under ground or far away from where the fallout could touch land. They also we're not all at once on one day as a nuclear war would almost certainly be or be close to. Firing them in the atmosphere above land and causing the radioactive dust particles of fallout would cause many of the plants and animals to slowly, or in a lot of cases, quickly die off. This can cause food chain issues, unbreathable air and toxic water. Radiation poisoning isn't exactly missing in test areas either. Bikini Atoll is still radioactive and so is the Trinity sight so I'd say comparing test areas to mass nuclear weapons usage is not a good comparison.
Why can't we use materials with lower boiling points to generate power?	You are correct that it doesn't matter what is spinning the turbines, as long as they are spinning. The reason that we use water instead of something else comes down to two reasons. First, we've got lots and lots of water, so it's easy to get and super cheap. Second, water is good at making pressure. The turbine spins because the evaporated stuff takes up more space than the liquid stuff, and that creates pressure. Water takes up more space than a lot of other things when it evaporates . There are certainly going to be things that are better at making pressure , but the cost-to-output isn't going to be as good because of that first reason.
How is the Universe expanding, but it's not expanding into a larger containing space?	Don't think of the balloon analogy as us being inside the balloon, but on the surface of the balloon. We're 2d, but expanding 3 dimensionally into an environment. So what are we expanding into? No idea. The answer is probably an equation that doesn't make a lot of sense anyways. Like n-dimensional matrix algebra.You might find it easier to think of it more like the definition of "distance" is changing. That is: it's effectively the case that "1 metre" is becoming a smaller bit of distance in the universe than it used to be.
What is the benefit of doctors and nurses in hospitals working shifts longer than 8 hours?	More days off. I work 12 hour shifts as an EMT - they keep exploring the possibility of changing to 10 hours or a mix of 12 and 8 hour shifts, but they can get fucked if they think I am giving up my 4 on 4 off pattern. I love 4 day weekends every single week . I work full time hours, but am off work 50% of the time, it's great. Makes it easy taking long holidays as well - 8 days of leave gets me almost 3 weeks off, fully paid.
How does Russia manage to antagonize much of the West when its economy is not much bigger than Australia or Spain???	Russia still has a robust intelligence system from the cold war. Human Intel isn't as expensive as fancy equipment. A single B2 bomber costs a billion dollars, that's enough to employ tens of thousands of agents for decades.
Why are mobile game ads are so bad?	Mobile games are first of all, hard to program and at the same time mobiles are not big on gaming, not many people invest in making big and good video games on phone. Also mobile game developers are usually reputable and have big companies like Supercell and such, advertising is not that necessary for them. So it's the low tier programmers and companies that advertise there programs on platforms that have a cheap price for advertising. That's why you are most likely to see a bad ad for a game on some random app than YouTube.
What happens to the brain when you zone out?	It goes into a fifth dimension beyond that which is known to man. It is a dimension as vast as space and as timeless as infinity. It is the middle ground between light and shadow, between science and superstition, and it lies between the pit of man's fears and the summit of his knowledge.
The controversy around the reliability of Wikipedia	Since Wiki can be edited by anyone at any time there is no way of guaranteeing anything in Wiki is accurate. However since it is so often used, errors do tend to be rapidly corrected and you can track the links to find where the information is supposedly coming from. So Wiki shouldn't be used as a sole or primary source of information, but that doesn't make it useless.
What is a good scenario to use the lower gears of an automatic transmission vehicle and why?	If you're getting ready to pass on a two-lane road, downshift in preparation of accelerating instead of waiting for the transmission to do it. Some automatics are slow to downshift when you hit the gas.When driving downhill to use engine braking and avoid relying too much on your brake pedal. This one applies mostly to the immediately lower gear , but if you're driving on a highway in certain conditions, such as a long uphill, or towing a trailer, your transmission might constantly shift between highest and 2nd-highest gear, trying to "hunt" for the best balance between power and efficiency. To stop the transmission from doing this you would downshift, but only 1 gear downGetting out of snow/mud. Keeping it in a lower gear allows more control and the slower the tires spin the less likely they will lose traction with the surface.Edit: words. Not enough of them.In addition to what other people have said, they're also useful on loose or slippery surfaces like snow, ice, or gravel when you're trying to maintain traction.
how do cameramen and women in films hide the cameras whilst filming so well when there is a scene with reflections?	As others have said, CGI and/or simple disguises . For a stunning example of the CGI approach, check out this shot from the Kenzo ad: _URL_0_ So many mirrors. All the reflections replaced with CGI. ", 'Sometimes they just drape something dark around the camera and hope the audience doesn't notice. Google "matrix door knob camera" for an example.
Why are computers and electronics in general restricted to binary system (0 and 1)? Why not 0,1 and 2?	At the deepest level, a computer still requires analog mechanisms. To use a 2, you have to define a 2 in some way in hardware. It's much easier to use 0 for off and 1 for on with high speed switching transistors. Using 1s and 0s in the right order gives you a way to represent 2 in binary: 0010.Modern flash memory is an exception. Each cell can store one of four, eight or even sixteen possible digits. The different digits are stored internally as varying voltage levels but these are converted to and from 2, 3 or 4 binary digitsBecause binary is really simple to implement and allows for full Turing completeness. There is nothing that can be represented in trinary but not in binary.
Is there any scientific reason why the US's shuttle launches were about as far East as they can possibly manage on their home soil?	Rockets launch to the East so they can use the Earth's spin to help them get the speed they need to stay in space. They are located as East as possible so that the lower bits of rocket they dump and the rockets that mess up all crash into the ocean rather than places where there are people living. The Soviet Union didn't really have such a place, so they launched from a place in Kazakhstan called Baikonur. Their failed rockets and rocket bits all fell on land, they claimed they would pick up their stuff, but they never really did. As a result the place east of their launch site is really really bad, because of the rocket bits falling on it and the poison in the rocket fuels the soviets used.
why isn’t it possible to keep Great White Sharks healthy and alive, as all attempts cause the sharks to die rather quickly in a contained environment?	I've heard that it is basically impossible to accommodate their swimming needs, and the only real solution was a literally impossibly sized pool with all corners rounded off so the shark couldn't keep running itself into them and had endless room to swim. I dont think that has been tested, and if it has, it wasn't a success that we heard about. Also that would be more like a saltwater lake than an aquarium at that point.
Why does rain have a calming effect on people?	This is a pretty subjective question. Not everyone feels calmed by the sound of rainfall. Ombraphobia and astraphobia are both somewhat common phobias. But for me personally, I feel calmed by rain because it reminds me that I'm safe, warm, and dry in my apartment or other building. It makes me aware of the fact that I'm protected from the elements, which can be a very calming feeling.
Why can a thermal flask keep items cold for 24 hours, but only hot for 12 hours.	All the more technical answers are totally true and good, but I would like to offer a simpler to understand alternative: Heat = energy. There is no such thing as cold energy that makes something cold, there is simply the absence of energy. So, when you have a hot drink you have a cup full of energy that radiates outward to its surroundings where there is less energy. The vacuum seal of the thermos attempts to keep it all locked in, but energy radiates, man. It's what it does. On the other hand, if you have a cold drink in a thermos you have a low-energy zone in your hand, which radiates nothing . Instead, it is the outside environment that has the energy and wants to get in, but the energy difference isn't that big so the vacuum is more effective at keeping the low-energy zone from the higher-energy environment.
the reflection on highways we see from a distance that disappears as we approach that point?	That's a [mirage]. The light from high-up things gets bent down to where you'd think the road would be.
How are paintings proven real or fake?	If the painting was supposedly painted before the first atomic bomb test samples of the blue paint can be analyzed to see if it contains radioactive isotopes of cesium and strontium that aren't found in nature until the first atomic bomb test.
Why do antidepressants dampen emotions?	Is this just with SSRI's because I start Wellbutrin at the end of the week and would rather not feel gray all of the time.
why does slouching and bad posture feel so much better than good posture?	It only feels better if you're used to it. I used to have a bad slouch that fucked up my back muscles, and for the first couple months of PT and good posture, I felt miserable, but a year and a half later, it actually hurts me to slouch.
Why do you get better performance when playing a PC game in Windowed (Borderless) than you do in Fullscreen?	Assuming it's the same resolution, you should get the same performance. If it's a lower resolution - perhaps because it's not taking up the whole screen, then it doesn't have to work so hard.
The saying goes “never add water to acid”. How come your stomach acid does not react when you drink water?	The issue is mainly with concentrated solutions of strong acids, and mainly of sulfuric acids. Because they heat up as they mix with water, there is a danger of so much heat being produced that it boils the solution and splashes concentrated acid all over you. Your stomach acid is HCl, where this effect isn't that strong anyways, and it is too dilute for that to be any real danger.
Is "yawning because of boredom" a cultural thing that is (unintentionally) taught to us or is it natural? And why?	It isn't known why we yawn at all. Yawning while bored isn't universal even within the same culture. It's unlikely to be a learned behavior because it is a reflex, but it's possible it is a conditioned behavior. For example, if you were bored a lot while you were tired, you could associate boredom with fatigue and that could make it more likely that you yawn while bored.You think we are unintentionally taught to yawn?', "I'm not sure what the reason is, but reading this thread sure is making my jaw tense asking for a yawn..! _/¯ )", '"Stuff You Should Know" did a great podcast episode on this. Worth a listen. Essentially most of theroies in the comments here are proven incorrect though they were leading theories for awhile. Current supported theories are that yawning cools the brain or is signals some type of alertness . In fact, it's been shown in some animals that yawning can be both contagious and an indicator of horniness.
How does the DMAS (divide first then multiply then add then subtract) hold true in real word physics and situations?	It doesn't and does. You could use any order as long as you were consistent and formed the equations correctly. Or just skip all order of operations and nestle things inside brackets working outwards.
Why is everyone blaming the "boomers" for today's economy?	Simple: They took advantage of everything the Greatest Generation left them, and then they closed the door behind them. They dialed back the necessary anti-crony policies that were put into place after the Great Depression, and they enshrined trickle-down economics for decades, a system that obviously, painfully, doesn't work for anyone except those at the top of the pyramid.
How does cruise control work?	All new cars have electronic throttle control, meaning the gas pedal is hooked up to an electronic switch that is then connected to the ECU . In older cars, the gas pedal was connected to a metal cable that opened or closed the throttle valve which increased airflow into the engine. The increased airflow would be sensed by the ECU and it would increase fuel flow. In older cars, the cruise control does directly connect to the gas pedal, instead it is connected directly to the throttle valve. You may still feel the gas pedal move, that's because the pedal is still physically connected to the valve, which is being moved by the cruise control. In modern cars, the valve is controlled electronically, so the cruise control just tells the ECU what to do.
how jumping in to water from a high place is a suicide	Water is only soft if you move slow. You know how a belly flop hurts from a 6' diving board? Now imagine 60'
Tuition Reimbursements and what it entitles.	If your tuition was $2000 or $5000 or $8900, etc. then they'll reimburse 100%. If it's $20,000 they'll reimburse $9000. Some companies might only cover, say, 50% of tuition costs instead of all . I believe the cost is taxable as a benefit.
why is bacon so different from the rest of the pig?	Back fat, belly fat, it all has it's own flavor, bacon obviously, is the most healthy choice!
Why do restaurants bother serving free bread/chips etc.?	That little bit of food actually makes you hungrier. I'm sure it helps with making customers friendlier. Most people are irritable when hungry. This is also the reason why Costco and other stores give free samples. You buy more food when you are hungry, and the samples help that process along.
Why do horses have horse shoes	Horse hooves are pretty soft. They're great for walking around on soft surfaces like wild grasslands and areas with softer soil, with the occasional running thrown in. They aren't great in mountainous areas or places with a lot of hard rocks and hard soils. They're really not great for pavement, tracks, or roads. And they're really not great when there is a lot of debris around. They're really, really not great when you have that horse pull a six hundred pound cart laden with goods, and/or throw a rider on top of them. Think about it like the shoes you wear. If you went and lived in the woods/plains in a nice, fertile area with soft ground, you really wouldn't need to wear shoes. Your bare feet would be more than enough to protect you. When you start having to walk around in cities, towns, or do any amount of physical labor that requires you to stand and move around a lot, it becomes important to protect your feet.
If Ethernet cable can transfer so much data, why not use this instead of HDMI and other cables for data.	* Ethernet is actually a system for transferring information. It happens to use Category 5 or 6 cable * You can do lots of stuff with CAT5 cables that has nothing to do with ethernet like your physics class and your Line 6 guitar.* There already are products that use CAT5 and CAT6 to get things like audio and video signal from one place to another.* BUT! The reason we have HDMI is because the movie studios wanted a technology they could control. * In order to make an HDMI cable, or a device that has an HDMI connector, you need to pay a license fee and agree to a legal contract that says you won't design your device in a way that lets people make illegal copies of protected content. * Back when DVDs were the main way you could watch movies at home, they forced everyone to switch their DVD players and TVs to HDMI.* Laptops went along with it and now basically everything relating to consumer video is HDMI.well, usb 3.2 with type c connectors seem to be becoming the "master cable" you speak of. I think that throughput is just better, and most importantly, it's really small.
How do medical examiners know that a victim was still alive when cuts/bruises etc occured?	Heart pumps when you're alive. Blood leaks, pools, spills, and all that fun stuff. Person dies, heart stops, no more moving blood.
Why do common household items (shampoo, toothpaste, medicine, etc.) have expiration dates and what happens once the expiration date passes?	I agree with other replies. Also though, sometimes it's just a messed up way companies try to persuade you to trash and repurchase a product you already bought.Related question: What happens if you leave OTC medicine in your hot car all summer? Does it lose its effectiveness to the point of being useless or even harmful?Shampoo does not have an expiration date. At least, there’s no requirement. You may have some brand that’s made a choice to put one on, but it’s purely for marketing. Unless it’s one for dandruff or some other condition or if they’re making an SPF claim or another claim for actives. Then it needs one because it’s considered an OTC drug. Source: I work for one of the largest contract manufacturers of personal care items in North America. And I write the instructions for how we fill and package the shampoo. So I need to know which ones take an expiration date.I've used toothpaste years after its expiration date. If anything it actually worked better. Think the oldest tube I used was maybe 8 years old. Used to know a guy who worked for Crest and had a storage unit full of tooth paste and other Crest things.
If adrenaline boosts our mental quickness and physical strengths, how come it isn't always pumping through our veins?	For an example of why you wouldn't want adrenaline constantly being released at high levels, look up pheochromocytoma. This is a problem where an adrenaline secretion tumor does exactly what you have suggested. Instead of a super human, you get high blood pressure, headache, sweating, high heart rate, high blood sugar , and anxiety . Elevated adrenaline is useful in short bursts in specific situations, but outside of that it is not going to feel good or make someone super human.I’m not a biologist or doctor. But my understanding is that we don’t constantly run adrenaline for the same reason we don’t run computers at the full theoretical capacity - it would wear you out too quickly. Adrenaline boosts quickness and physical strength by clocking up the amount of energy you burn, reducing your awareness of pain, and withdrawing supplies from your periphery. It also increases your fear response and other negative responses to stimuli. This means you would have trouble digesting food and recovering from injuries, would endure increased stress levels, and wouldn’t be as capable of creating the solid social bonds that would do a better job of keeping you alive. Overall, being constantly on edge isn’t as worthwhile as having some time to relax.It's like red-lining your car. It gives you slightly better performance at great cost. It's like running at 110%. You usually don't need the extra benefits it gives you except in an emergency. With humans, we have 18 or so hours a day where we have to operate, and we're already a well-tuned machine, in evolutionary terms.
Why is Mercury poisonous? What exactly is it doing to the body, and why can it not be resisted?	Elements come in different oxidation states . When Mercury lacks two electrons ), it gets confused with other metals like Magnesium ) by certain proteins that usually contain Magnesium. These proteins incorporate Hg instead, which renders them useless. Since Hg stays in your body this process continues even after the useless protein got destroyed by the cell. Hg just slips into another comfy pocket of a protein. That's why Hg^ is poisonous.I can’t answer your question, but “The Disappearing Spoon: And Other True Tales of Madness, Love, and the History of the World from the Periodic Table of the Elements” is a fascinating book on how the elements were discovered and worth a read if the topic interests you.Elemental mercury is actually fairly nonreactive and does not cause much damage if ingested it's been used in fillings like gold. Other metals can also be fairly toxic in different oxidative states, even gold for example. It is mercury cations and mercury containing compound like dimethyl mercury as well as mercury vapour that cause major damage and accumulate in parts of the body where other elements would naturally be, messing up the chemistry of the body causing proteins to function incorrectly, resulting in brain damage among other problems that will eventually result in death if they are left untreated and continue to accumulate in the body, since we have a hard time excreting certain heavy metals once they form compounds within the body. Chelation therapy is the main treatment for heavy metal poisoning.
How much does it really matter where I buy my gas? Are “name brand” gas stations any different?	It used to matter. Gasoline is a formula of fraction products of petroleum. Before standards, some brands were famous for smelling different. Some charged more and were more expensive, or had a following. It hasn't really mattered since before widespread regulation on the quality of gas, maybe 70 years or so.
Why aren't there many naturally occurring liquid substances on Earth? Does matter have a "preference" for being in a solid and gaseous state?	What do you mean? Our whole planet is covered in water, but even that is insignificant. Below the fifteen or so miles of crust is an entire planet of liquid rock. We're like 99% liquid, dawg.
what does tax withholding mean?	You have a job, which means you have income, which means you owe income tax and social security tax. There are two ways that you can pay: 1) You take all the money home, but then tax season comes around you owe the government $2,000, and have 2 weeks to pay. Hopefully you were saving up for that expense. 2) Your boss withholds $20 per paycheck, and sends it to the government once every few months when the business does its taxes. Then when you do your taxes, you owe the government $2,000, but they already received $2,200 from your boss, so now the government owes you $200. & #x200B; If you want your boss to withhold money for you, you can have him hold more or less. That will then effect how much you owe, or get refunded, in April. All states do this. Some states call it withholding, some call it credits, some call it exemptions. It's usually filled out when you start a job, on a W-4 form. When you file your taxes, your boss will give you a W-2 which records all the withholdings they paid in your name for that year.
If we've discovered recently that modern humans are actually a mix of Homo Sapiens Neanderthalensis and Homo Sapiens Sapiens DNA, why haven't we created a new classification for ourselves?	In terms of taxonomy something isn't a different species if interbreeding is still possible. Neanderthals were physically and culturally different but still bred with homo sapiens to produce offspring that could themselves pass on their traits. We named them before we knew what the path was that led to Neanderthals was. When I was in grade school we were taught that homo sapiens descended from Neanderthals . It was a big deal when we learned that we lived side by side with them and even interbred with them. I'm culturally different from the French and I am physically shorter and weaker that my neighbor but we're still the same species.Additionally, not all modern humans have Neanderthal ancestry. There were a few subspecies of H. sapiens in Europe and Asia that were interbreeding, and some people never encountered any of them and have no ancestry from those other subspecies. Sometimes taxonomic categories are invented to describe significant but biologically inconsequential differences between otherwise very similar populations.It's also worth keeping in mind that there are modern humans with no Neanderthal DNA in sub-Saharan Africa. You really wanna go opening that can of worms and making Africans a different species to Eurasians?
How does skin tan? Why is it so dangerous without proper sunscreen?	Dropped biology last year but I'll try, please correct me if I'm wrong. When you skin is in the sun it produces melanin I believe, which protects your skin against harmful radiation from the sun, and as a side effect browns your skin. The radiation is harmful because it can screw with the genetics of individual cells , possibly turning those cells cancerous.
How do you store medicine properly when it's hot?.	Your refrigerator is not humid, it's cold, but the all the humidity inside the refrigerator condenses on the evaporator coils. That's why you need to store vegetables in the crisper drawer
How hasn’t natural selection weeded out individuals with bad eyesight, fatal allergies, and everything of the sort?	Because survival in modern society isn't reliant on such things. Think about maybe 2000 years ago. Say you have poor eyesight, you would be more prone to being robbed as you may not be able to make out people approaching at night or may not be suited for high paying jobs. You end up poor and no woman wants you. Lets say you have gluten allergy back then and the only thing you can afford is bread. Sucks to be you. There hasn't been enough time for natural selection to take place on these things and at this point in time, it's completely halted due to modern civilization
How are emergency numbers (e.g. 911) handled near borders of countries?	Well here in Australia our emergency number is 000 but if a US citizen is here and needs emergency services and just instinctively dials 911 it will redirect to 000. So tl;dr I think any emergency number will just redirect to the country you are in. I could be completely wrong as I'm just basing it on what happens in Australia.
why is it that when you massage your own scalp/body you feel no satisfaction vs. the pure satisfaction when someone else massages you?	I assume it's at least partially because you have to strain your arm/shoulder muscles to massage something else, so you can never fully relax. And partially because physical contact releases endorphins.It may have something to do with our ancestors and their social grooming habits as bonding mechanisms. The things that help us survive and reproduce tend to make us feel good, like the constant touch of others / deepening social bonds.Same reason you can't tickle yourself. Part of it is that if you're the tickler, you know when it's coming.
why is using cruise control more efficient than simply maintaining the speed manually?	Because the exact amount of engine revolutions needed to maintain that speed is being used. This means that provided you don't suddenly go up hill or have to make sudden changes in direction, the amount of fuel used is constant. When you drive manually you are constantly speeding up and slowing down based on the pressure of your foot on the accelerator. This is less efficient overall.It's because cruise control has sensors to determine current speed and growth or decline rate of said speed to use minimal gas to get back to cruising rate with minimal fuel usage - as opposed to human who goes "fack too slow" "fack. Speeding." repeat. Tldr. Math is faster on a computer than any human mind. Maintaining speed given current velocity varies based on your terrain. Cpu wins. Sorry if this was said.
Why are animals that are much stronger, faster and can easily kill us afraid of us?	I don't know about easily. Intelligence beats strength, and a lot of animals are cautious of things that could be a threat. You lose some teeth or claws in the wild and it could spell the end.
How does Netflix stay in business?	You have to consider, that they could pay back the debt with their returns, but they make even more money reinvesting that debt into production then paying back the money to the banks. If you owe the bank 100 million and they're charging 8% interest you could pay them the 108 million back, and that's that or you can pay them 8 million, and reinvest that 100 million to make another stranger things or making a murderer, which drives up your subscription base another 200 million pay the bank their 8 mill, rinse repeat.
Why are gold, silver, gemstones, etc. considered valuable?	Gold is very hard to counterfeit, because of it's very high density. It's also very stable . Characteristics like those make gold a very good currency when there's no trusted authority to back something else.
Why does fire turn from orange to blue the hotter it gets and why is the sun (a very hot thing) stay orange?	The sun looks orange to yellow but it's really white. It looks orange for the same reason the sky looks blue. White light is made up of all the colors in a rainbow, but the blue and violet get scattered more heavily, and so when you look at the sun, most of the blue light has basically been washed out, leaving the more orange and yellow hues.Blue light require more energy to create than red light. This means that you need a hotter flame. The reason the sun is yellow/white rather than blue, despite being far hotter than everyday fires here is due to a few factors. First is the material, probably hydrogen and helium. On Earth the main elements of the air are nitrogen and oxygen. These will enjoy light differently. The other big difference is the pressures of the gasses involved, with the suns atmosphere under far larger pressure.
Why just landing on the moon is a big deal and how will it benefit us?	back in the 60's, it was a big waste of money. but it was deemed worthy because it was a dick waving space race with the commie Soviets. & #x200B; a good reason for going to moon is using it for either mining or scientific research. ISS already does alot of research in this area. but a continuous resupply mission to the moon will cost 10x more than a ISS resupply. the moon surface is much more harsh than ISS orbiting the Earth. it would make the cost of going to, maintaining, and extracting resources from the moon extremely expensive.The moon is made out of cheese. what do you want to be when you grow up? A coward afraid of their own shadow? No, and thats why.Now shut up and eat your Soylent Green, there are kids starving in North Korea.
how do people know which mushrooms are fit for consumption and which are poisonous	By trial and error, but carefully. How do you eat food carefully: [_URL_0_] Plants are not usually either definitely fatal or perfectly safe. You start with very small amounts and test them in various ways. If it is bad or you react to it, don't eat it.
why do you need to bring your temperature down?	This helps increase immune system activity and decrease viral infection rates, but it's also dangerous. Your central nervous system can only function properly in a very narrow temperature range, and keeping it too hot for too long will cause permanent damage. A low grade fever is a normal part of the immune response, high fevers from an overzealous response to an aggressive infection do more damage than they prevent.
Why does soap clean your body and yet make the shower filthy with grime at the same time?	Soap clings to the dirty stuff and makes it easier for it to wash off. The soap isn't perfect and can drop the dirty stuff in the tub. i think
How does the 5th amendment work and why is it not taken as an automatic admission of guilt?	The state can't torture you to get a confession. The state can't trick you into confessing to another crime while you're testifying against a different criminal. The state has to try to convict you based off other people's testimony.
What determines music taste? Why are some sounds or genres more pleasing than others?	I think it all boils down to music you relate to. So you will be attracted to similar music. There's also the understanding of a genre. Once you understand it and can see patterns or know how different sections are made you appreciate them more. It's also why you can like vastly different genres
What causes ripening fruits to change color?	Really ELI5: Fruits change color as they ripen because the chemicals inside of them are getting them ready to feed the seeds inside. Thorough explanation: i actually don't know much more than that, just that it has to do with enzymes and such
why the more blades on a propellor is not better	Welp yes, but actually no. The more blades on a propellor the more surface area you have. This means that yes you would have more thrust, but you would also have more drag. More drag means that you would need a bigger and stronger engine or motor to spin that propeller. Adding larger engines increases weight and larger engines typically require more fuel, also increasing weight. I'm not an engineer, but I'm sure there's a formula out there that can calculate the weight to thrust ratio of different engines with different number and sizes of props.
Why is ingesting nicotine toxic but we can smoke cigarettes constantly?	You know, injecting heroin is actually less of a direct rush than smoking it. Lungblood gets to the brain faster than that in the arm. Injection is just less wasteful for the homeless guy who doesn't have a lot of heroin money. You could eat as much nicotine as is in a cigarette and be fine. You'd get maybe even less of a rush, because the lungs get it there faster. It's because vape juice is super concentrated before it's vaporized, that causes it to prove fatal to the curious kid who took a swig.
why are housecats terrified of getting wet, when their instincts include catching fish?	Cat fur gets heavy when it gets wet. Imagine wearing a wet tshirt that you can't take off untill it dries. Also, unlike dogs, cats can't shake themselves dry, the only way they can get the water out is to lick it out.
What exactly makes McDonald's hamburgers so unhealthy.	Sauce mostly. It's also generally accepted that the burger will come with cheese, and fries, and a soda, leaving the consumer with few daily calories left if they want to avoid weight gain

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