Subset (10)

eli5 · 25k rows

Split (1)

train · 25k rows

query stringlengths 20 300	positive listlengths 1 1	negative listlengths 1 1
If tanning is your bodies defense against a bombardment of cosmic radiation, do those mirror tanning contraptions do anything at all?	[ "Tanning isn't related to cosmic radiation. It's a defense against ultra violet radiation, primarily from the sun. Consider: Cosmic radiation is the same at night, but you don't get a tan at night. A mirror reflects the visible spectrum of light, as well as ultra violet light. Have you ever used a mirror to shine s...	[ "From [Wikipedia](_URL_0_): > Traditional chemotherapeutic agents are cytotoxic, that is to say they act by killing cells that divide rapidly, one of the main properties of most cancer cells. This means that chemotherapy also harms cells that divide rapidly under normal circumstances: cells in the bone marrow, dige...
in a lot of film versions of A Christmas Carol Scrooge speaks with received pronunciation. is that accurate to what someone from his type of job & background would have sounded like?	[ "Scrooge attended boarding school (he revisits it in his first visit with the Ghost of Christmas Past) so received pronunciation (sometimes called \"public school pronunciation\", or PSP) makes sense. As a filmmaker, received pronunciation would also suggest power and authority, suggesting Scrooge is \"The Man\" an...	[ "Just in the Old Testament. In the New Testament, they made several changes to make it appear more civil. Some changes were even more controversial, such as making Satan shoot first and adding Dewbacks on Noah's Ark. I'm still waiting for the Old Testament to appear on Blu-Ray." ]
How do fans make the air cooler?	[ "They don't, it just feels cooler because there is always small amounts of moisture on your skin, even when you're not sweating, and the wind makes it evaporate faster." ]	[ "Modern computers use variable speeds that require a variable amount of power. When a computer needs to process information quickly it will increase its \"clock speed\" and that requires more power. That power is not used at 100% efficiency and therefor more power = more heat as the excess energy is converted to he...
Why euro coins have country specific designs but the notes haven't	[ "Coins are very rarely counterfeited, so there is little risk in having a variety of designs. Notes are often counterfeited, so having a variety of notes makes detection more difficult. A shopkeeper may not know all the designs and accept a bogus one by accident." ]	[ "They probably are testing out the waters to see how well the product does. In America where Apple has a dominance over what everyone thinks of when talking about tablets (sportscasters getting paid to advertise the Microsoft Surface and calling it an iPad on tv), they don't want to spend a bunch of money on advert...
How did Mayweather win that fight?	[ "Pacquiao was the aggressor for most of the fight, and he swung a lot more. The crowd was clearly on his side, and Mayweather rarely drove forward. But these things don't matter to the judges, or at least they shouldn't. Who was better at landing punches, who dictated the pace, who did the most damage, these thing...	[ "No one but the writers of the script know this for sure, but there have been many comic book where Superman and Batman disagree on something, maybe Batman took the last Natty light or something." ]
Is there a human limit to the 100m world record?	[ "Yes, there is: somewhere between 1s and 9.50s, but we don't know exactly where it is, because of the Sorites paradox." ]	[ "I would think the ultimate limitation is the grain size of the crystals in the film. Table 2 in this PDF gives sizes and scanning technology: _URL_0_" ]
Why does saying or pretending to be confident, happy or relaxed eventually make you feel that way?	[ "It goes along with the saying “fake it til you make it.” If you tell yourself you're going to act or feel a certain way, eventually it'll happen." ]	[ "It has to do with your sleep cycles. For the average person, a sleep cycle will last around 90 minutes. You have light sleep, medium sleep, deep sleep, and REM sleep, and they all take place within the cycle. When you wake up during REM sleep (at the tail end of the 90 minutes), you feel a lot better than when you...
How do scientists know that dinosaurs had lizard-like skins?	[ "We've found some [fossilized skin](_URL_0_). From there it's mostly educated guesses based on other anatomical features and comparisons to living animals." ]	[ "We didn't, where do you think jackets and coats came from? It started as long cloaks, which turned into shorter riding cloaks, which we gave sleeves and became jackets and coats." ]
How do they populate a newly built school? If you just have students moving up (i.e. from primary to a secondary school), you'll just have one year group.	[ "Typically a school is built in an area that has a need for additional seats, and will be populated with students migrating in from existing schools in the vicinity." ]	[ "It has to do with the contracts the networks sign for the show. Typically shows are contracted by the season - but often they will buy a season with a certain number of episodes with an option to buy more episodes under that contract if the show is successful. For example - They will sign a contract for 1 season o...
Programmers. Why does a semi-colon mean "new line" in some scripting langauges?	[ "It doesn't mean \"newline\". It means \"end of statement\". It's used instead of period because periods are used for other things. In a lot of languages, such as Java, and C, the semicolons are required. Other languages try to be more flexible and allow you to use either a new line or a semicolon." ]	[ "Imagine you are a travelling salesman, and you spend most of your time driving from place to place across the country. Today you need to get from Denver to Dallas. You could use High Level Navigation. You know how to get from Denver to Wichita, Wichita to Oklahoma City, and Oklahoma City to Dallas. String those to...
how a black man and a white man with all the same size body parts have distinct voices where you can tell their nationalities apart before even seeing them	[ "Accents don't have a physiological basis. It's learned behavior. There's nothing unique about people with the same accent." ]	[ "A lot of reasons: Old movies had the soundtrack imprinted on the film, it was analogue and intrinsically noisy - like cassettes, the same was true of video. Also copying the film to make a new print or change the format would introduce more noise. To deal with that Cinemas had quite sophisticated analogue noise re...
How electricity is generated, transmitted down massive wires, and ends up powering a small electric shaver in my home.	[ "Generators push and pull electrons creating a wave of electron motion similar to waving a rope held between two people back and forth to create a wave shape in the rope. The actual fibers of the rope (electrons) don't travel the whole distance between 1 person to the next, but that wave they make does. This wave i...	[ "[Here's a strike in slow motion](_URL_0_). The initial \"feelers\" follow randomish paths determined by which nearby bit of air happens to have the least resistance. As soon as one of those paths reaches the ground, it becomes the path of least resistance to the ground because it has left behind a trail of ionised...
What would happen if you deleted all the electrons in the universe?	[ "Short version: Everything would explode. Quite litterally. Long(-ish) version: every bond between atoms is based on electrons (for example, H20 exists because each Hydrogen shares its one electron with Oxygen, which, in turn, does the same, forming a bond that keeps them attached). So, well, there'd be no molecule...	[ "It would actually cause the economy to contract. We spend all the money we have, plus money we don't have by going in debt. With no debt, we are only spending what we have and not spending what we don't have. I have $10 and can borrow $10 to spend. I can now insert $20 into the economy through spending. Without t...
why musicians on youtube need to wear headphones while they record but live musicians don't	[ "Live musicians use stage or in-ear monitors which do basically the same thing - allow them to hear themselves." ]	[ "It works the same way, speakers and microphones (in a reversed way) work. In order to understand this subject, a little knowledge in Physics is required. It's the Lorenz Force, which causes a conductor to move, when being within a magnetic field. This force is proportional to the strength of the magnetic field and...
Why is the author's name on a book so much bigger than the title of the book itself?	[ "The ultimate goal of the cover of the book is to sell the book. All of the choices involved in the layout, colors, images, text, and font sizes are made with the question of \"Will doing this thing sell more books?\" in mind. If the author's name is larger than the title of the book, it is because the publisher of...	[ "Consider two airlines: The first never overbooks. People regularly cancel and the airline is unable to rebook those seats quickly enough, so their planes tend to fly with lots of empty seats. The second overbooks. People regularly cancel. Since they have overbooked, they can keep the planes full. The first one has...
How did the idea develop from 'the sun is a ball of literal fire' to 'it is a nuclear fusion reactor'?	[ "In the 19th century, the proposed mechanism of the sun's heat was [Kelvin-Helmholtz contraction](_URL_0_). Basically this happens when a cloud of gas with mutual gravitational attraction starts to contract under gravity, and this contraction heats up the gas until it gets really hot. This mechanism is indeed respo...	[ "Artemis is the goddess of the moon, actually. But whether her gender played a factor in the choice of Apollo over Artemis is unknown to all but Abe Silverstein, the new Director of Space Flight, who named the project in 1960. According to Silverstein, he was captivated by the story in a book of Greek myths that ...
Air Quality Index (AQI) Reports	[ "There is no standardized way to measure \"air quality\", everyone is free to label it as they wish. The number indicated by one system isn't intended to be compared with other systems, but with itself over time. If the number is going up the quality is deteriorating, that kind of thing. It's like ranking temperatu...	[ "I see several versions available online. [This](_URL_0_) one looks pretty comprehensive, though I haven't used it myself. That link is part of a [larger project](_URL_1_) that put Charles Keppler's Indian Affairs: Laws and Treaties online." ]
does the use of decongestants and antihistamines lengthen the duration of a cold?	[ "A surprising number of sicknesses are not mediated so much by tissue damage from invading viruses and bacteria, but rather from the immune response itself. Examples would be in Tuberculosis, Acute Rheumatic Fever, and other hypersensitivity reactions. The common cold (usually either a rhinovirus or a coronavirus)...	[ "From [visual tim]( _URL_0_) I don't see why hummingbirds wouldn't operate faster. The hummingbird's metabolism is what fuels their high speed, and their nutrient rich diet supports it. If their nervous system can perform at such high speeds, it stands to reason their brain could. I wasn't going to mention this wit...
Why does iron rust faster in the presence of saltwater?	[ "Rust is iron oxide, the result of oxygen interacting with iron in the presence of water. When this happens, the iron oxide forms a barrier to the rest of the iron behind it, so other factors, like wind erosion, need to remove the rust to get to the iron underneath, to then change that to rust. With salt water, th...	[ "It increses the osmolarity of your blood: _URL_0_" ]
Why Does Base Ball Have Umpires and Every Other Sport Have Referees?	[ "couldn't tell you but baseball isn't the ONLY sport with umpires. Here in Australia we prefer to use the term umpire over referee so you have a basketball umpire, an AFL umpire, a cricket umpire. They're exactly the same thing anyway so why does it even matter? It's essentially aubergine vs. eggplant." ]	[ "You are expected to tip for other services. This includes hairdressers/barbers, cab drivers, valets, coat-check employees, bartenders, hotel doorman who helps you carry your bags, and a few others." ]
What are the chances of catching a venereal disease from poop splash in a public restroom?	[ "By placing a piece of toilet paper on the surface of the water where the projectile will enter you can effectively minimize any splashback. [video demonstration - SFW](_URL_0_). Your digestive tract is not really inside your body as it is a closed tube that runs from your mouth through to your anus. As the feces e...	[ "So do things like Malaria and Yellow Fever need significantly less virions to start the virus in someone or how do they spread while HIV does not?" ]
What exactly are orchestra conductors doing with their hands and/or conductor sticks?	[ "First and foremost keeping the beat and indicating the down stroke for each musical bar so that the players can keep communal time and know how many bars pass when resting or holding notes. Secondly they are indicating the dynamics, visual cues that remind players when to play louder, or softer, or with brevity, o...	[ "Basically, in countries that have private ownership of land, land surveyors give their opinion on where property lines actually are on the earth. We research deeds, maps, etc. to determine where the lines are thought to be and then go to the property to find evidence of where the original survey marked it. The ins...
Help identifying coat of arms scroll [x-post r/whatisthisthing]	[ "A brief Google search would lead to the Hislop family from Scotland. Having a search of the motto, I get the following: [link to discussion](_URL_1_). [House of names has a page with a very similar coat of arms](_URL_0_). It seems like a relatively popular family name. Is it possible that her maiden name / one of ...	[ "I don't know exactly what you mean by \"authentic\". There is no such map dating from the 9th century. The map itself is not very good - it overemphasizes the reach and coherence of a lot of polities. England, for example, doesn't exist, and what did exist certainly didn't look like that. EDIT: After some discussi...
When we look at a rocket launch, what causes the flight path/trajectory to have that curve?	[ "The curve is because being in orbit means going sideways, not up. The ISS is moving at 17000mph sideways (around the Earth), but not changing height/altitude. XKCD has a [phenomenal explanation](_URL_0_) of this, but here's the main point: Gravity in low Earth orbit is almost as strong as gravity on the surface. T...	[ "If you lived a few thousand years ago, you could make a good map of the constellations of the zodiac piece-by-piece at night. Then, at sunrise or sunset, you could measure the angle between the sun and celestial objects that are visible even in daylight: the Moon, Venus, and Jupiter are the best choices. You then ...
Why are objects in the rearview mirror closer than they appear?	[ "In order for it to be effective, the passenger side mirror is parabolic. This means the surface of the mirror is curved, allowing for a wider range of visibility. However, curving the mirror also effects the accuracy of its magnification, which is why things in the passenger side mirror appear to be further than t...	[ "It depends on the aerodynamics of the cars involved. Pull your minivan a couple car lengths behind a semi-trailer, you'll feel the drafting effect. If you have two fast cars with good aerodynamic coefficients, you need to be less than a foot apart." ]
Why do cacti always seem to have spikes or barbs?	[ "Because the cacti have adapted to live in harsh and hot environments, they evolved into spikes. Normally those spikes are considered as leaves of the plant. Having a classical shaped leaf would cause cacti to loose excessive amounts of water in hot and arid climates via evaporation so they evolved into spikes in ...	[ "[Carbonated water](_URL_1_) is better known as a solution of carbonic acid and has a pH between 3-4 (read: fairly acidic). The [receptors](_URL_2_) that [register \"hot\" or \"spicy\"](_URL_0_) from things like [capsacin](_URL_3_) (the chemical that makes the hot spice of chilis) are actually cation channels in ad...
How does someone born without a birth cirtificate or Social Security number obtain identification later in life?	[ "In the past, it was very common for poor people or people living in rural areas to not have a birth certificate. Born at home, far from any doctors or hospitals with the assistance of other women. At least 2 of my father's brothers have the same \"birthday\" on their birth certificates, for pretty much that reaso...	[ "It depends. In the US and other 1st-world countries, you can use tax records, asset prices (assets are stocks, real estate, etc.), salary data and other freely-available data to come up with a good guess. Other countries might require some more guesswork, but the principle is the same." ]
Why does winter get colder after the solstice when days start to become longer?	[ "Temperatures will lag behind the solstice like this because the earth retains energy. The solstice is the shortest day, so on that day the smallest amount of energy is received from the sun, but the ground and the lakes and oceans will still retain a lot of energy. The ground is basically a giant reservoir that ma...	[ "> How does that happen with constant sunlight? Are the Sun's rays weaker due to the angle or something? Yes, the angle is the issue. Consider that there is a certain amount of energy per area of exposure to sunlight. Imagine a sheet of paper which is flat vs edge on to you. The more angled the sheet of paper is to...
Why does almost all EM radiation pass through solids easily, but visible light is stopped by the smallest obstacle?	[ "All radiation has different penetration. Even light. UV is damaging because it penetrates the skin. X rays are stopped by bone and gamma passes through. On the opposite end, different frequencies of radar can be used to better image rainstorms because they penetrate varying degrees of water saturation in the cloud...	[ "I had to consult his Nobel prize lecture to get some of the experimental details. It is well worth a read. _URL_0_ Lenard seems to have worked with electrons with energies around 30 keV (that is, accelerated by 30000 volts). Electrons of these energies will be fairly efficiently absorbed by materials on a length s...
What's the difference between a moth and a butterfly?	[ "Both moths and butterflies belong to the order Lepidoptera. Butterflies actually evolved from within the moths, they're like a specialized group of moths, making the moths a paraphyletic grouping while all butterflies share a common ancestor. Morphologically I usually use the antennae to tell them apart, it's the ...	[ "[The Straight Dope covered this](_URL_0_). Basically, they started out as being made by two different production teams, but after a certain point, they became essentially interchangeable, but they kept both names going." ]
Is MDMA really harmless?	[ "Layman here, but I did spend a lot of time doing drugs and researching on [erowid](_URL_0_) in my younger days. It seems like you know what you are talking about and already know this information, but this information needs to be in this thread for someone who clicks across it an decides to use this thread as ...	[ "the long term health risks, also have you ever been around someone on a cycle?" ]
What causes people to lose large chunks of memories after psychologically traumatic events? Is there any fix/cure?	[ "It's not that they lose it afterwards so much as they weren't properly recording it during the event. Panic does not allow for hardly any memory processing to occur. Too many things happening at once and survival depends on things outside of remembering and recording." ]	[ "One word: Repetition. You know all those song lyrics because you listened to the songs thousands of times. Names are easily forgotten because in our own minds, names are not nearly as important as the idea behind them. You often forget names quickly because you instead incorporate the idea of the person (who t...
- why does it hurt to get water in your eyes, but not when you cry?	[ "I'm gonna take a stab in the dark Saline eye drops don't hurt when you use them, right? Salinity of water...salt content? Tears taste salty so they don't hurt...? //drunk as shit" ]	[ "Probably just because you haven't practised doing it one way but do practice the other way because you do it out of habit. I've never really thought can do it both ways without a problem, and if you tried for about a week you probably would be able to as well. I think this because I remember what it was like learn...
How do we feel pain in dreams when we're perfectly fine and unharmed in the real world	[ "Like other senses, pain doesn't come straight from the nerves--the experience of pain is the brain's interpretation of the nervous signals. Dreams or your imagination can cause very real pain, just like you can have highly realistic hallucinations." ]	[ "Good question!! I do it a lot and have no idea why. I suppose it's a kind of primitive thing. Animals do the same. They nip at us and" ]
How do astronomers/scientists know so much (in fine detail) about our universe?	[ "Its just the results of observation plus math. More recently also computation and virtual modeling." ]	[ "To a 5 year old? Only Carl Sagan can do that.... _URL_0_ _URL_1_" ]
Sometimes when i get maybe 2 -3 hours sleep i feel great when i wake up, but sometimes i get 8 - 10 hours sleep and feel like crap and have to go back to bed later because im tired. Why does this happen?	[ "It has to do with your sleep cycles. For the average person, a sleep cycle will last around 90 minutes. You have light sleep, medium sleep, deep sleep, and REM sleep, and they all take place within the cycle. When you wake up during REM sleep (at the tail end of the 90 minutes), you feel a lot better than when you...	[ "Some of it: A lot of it has to do with the chemicals released after ejaculation: \"men release a cocktail of brain chemicals, including norepinephrine, serotonin, oxytocin, vasopressin, nitric oxide (NO), and the hormone prolactin\". [ref](_URL_0_). These chemicals make us sleepy afterward. So doing this sever...
What was the ANZAC contribution to the Vietnam War?	[ "It's an old post, but I've previously answered a question on \"[how did Australian Counterinsurgency tactics and strategies differ from those employed by the US in Vietnam?](_URL_0_)\" which might interest you." ]	[ "You do realise that Australia has the AFL Draft right?" ]
Why is it that in some situations minutes feel significantly longer than in other situations?	[ "“When you sit with a nice girl for two hours you think it’s only a minute, but when you sit on a hot stove for a minute you think it’s two hours. That’s relativity.” -Einstein" ]	[ "Similar questions have been asked several times before. You may be interested in the following posts: _URL_3_ _URL_8_ _URL_6_ _URL_0_ _URL_1_ _URL_4_ _URL_7_ _URL_2_ _URL_5_ _URL_9_ There are lots of really great questions and answers in /r/askscience that unfortunately get buried because of the high volume. It's ...
How to legitimately change your last name?	[ "I just recently did this! I can't tell you about maybe something weird in your county, but you go to your county of residence. It was super easy. I filled out forms and showed up on the date and time that they have open for name changes. The judge asked why I wanted to change it, I just said I preferred my mother'...	[ "In the middle ages, local churches kept many forms of records regarding baptisms, consanguinity, etc. If you were a serf, there were also manorial records." ]
How can guitar players still have the finger dexterity to play well when they are drunk? MIC	[ "I would propose muscle-memory to be an important factor in helping them play while intoxicated." ]	[ "This is a loaded question Is the music industry filled with drug abuse compared to other industries? Do you have some metric on this? Actually not music, but there are lots of research on industries as a whole Sure musicians use drugs, so do miners, people working in retail, bankers, teachers, and construction wor...
Why when you look directly at a light source and then close your eyes see the shape of the light?	[ "Looking at something exercises the rod and cone cells in the back of your eyeballs which then send the signal down your optic nerves to allow your brain to process the information. If the subject is very bright, then your rod and cone cells get overworked and start to become less sensitive to whatever type of ligh...	[ "Natural depth perception is limited to about ~10 meters. Beyond that the brain uses certain clues (objects being smaller when farther away, also shadows, contrasts, etc). The brain is good at guessing how an object would look if it were closer and farther away to build a 3D image. But this is not \"true\" depth pe...
Does fire reflect light, an if so, what color is it? In other words, what color would fire be if it didn't emit light?	[ "Since the light emitted by fire is simply the result of electrons jumping energy states during a strongly exothermic chemical reaction, fire would have no color if it didn't emit light. If you spray a bunch of AXE body spray on the sidewalk and light it at night, you usually see a faint blueish color to it. The bl...	[ "It isn't the lava that is turning into flames- it is the material it is touching. The lava is (as opposed to magma) at the surface and there is oxygen in the air. This is how the combustion can occur. There are plenty of videos online you can watch of lava burning things- [such as a ravioli can](_URL_2_). You can...
The closest star to earth is 4.3 light years away. Is this par for the course in the Milky Way?	[ "The density of stars decreases as you move away from the galactic centre. There, stars are much closer together." ]	[ "We don't know for sure... but assuming Earth is average, we can look at how long it took for multi-cellular life to arise here and assume that's how long it takes, then apply that to how long we believe Mars might have been conventionally habitable. I haven't looked up the numbers recently, but I'm fairly confiden...
If flying a plane or helicopter can be so simple using a controller or keyboard in a video game, why do their real controls need to be so elaborate?	[ "Because there are far more variables in real life than there are in a video game. In a video game you are flying without wind, usually with sub-par physics (i.e, game physics != real physics, even in only minute differences), you don't have to worry about other planes or listen to traffic control, your vehicle is...	[ "_URL_0_ Short answer: the physics change with the scale. If you built a house exactly to scale, but 3 times its normal size, it would collapse under its own weight. Conversely, if you build the house at 1/10th scale, you could probably drop it several times its height without much damage." ]
How does industrial-scale bottled tea production work? Do they just boil tea leaves in huge vats?	[ "Depends on the company. Honest tea does actually get the tea leaves and boil then in huge vats and then bottle them. However, most other bottled teas are just powders that they mix into water and then bottle. Learned this on the 'How I Built This' podcast." ]	[ "You know those ridiculously low shipping prices you sometime get on items from China? They get that low because they ship in bulk, so they have to wait until enough items are ordered and they can send it to the local (American, European etc) sorting station. Which results in low prices but takes a long time." ]
Is there a material that blocks magnetic attraction ?	[ "A magnetic shield doesn't really stop a magnetic field, it just redirects it. It turns out that materials that are good shields are those that are attracted to magnets. For example, steel. If you put a big enough and/or thick enough steel wall between you and a magnet, you can stop the magnetic field from reaching...	[ "search askscience for a better answer but it would have to be very strong, I think there might be affects before you get strong enough to make the dimagnetism of water what kills you" ]
Why isn't there ever lightning in snowstorms?	[ "There is, sometimes. It's called thundersnow. But the reason that it's not as common as with rain is because snowstorms are less energetic than thunderstorms." ]	[ "Commercially frozen meat is often flash frozen, this means that the ice crystals formed are small and don't damage the meat cells very much. If you freeze meat at home it's a much slower process, Large ice crystals form an like little spears puncture the cell walls of the meat. This means that when it defrosts the...
Why does steel wool burn?	[ "well, first off, burning and rusting are both oxidation. one occurs quickly and the other occurs slowly. the main reason steel wool burns is that it is very porous and so air can get inside it to speed up the oxidation process. pretty much all that is happening is that the steel is giving up electrons to the oxyge...	[ "Have you ever broken a glass and you get those tiny (almost microscopic) shards of glass under your skin? You can feel that they are there, and it is a mix of itchy and maybe some slight discomfort? Same thing for the insulation. It has tiny shards of glass in it." ]
Why do movies playing at 24 fps look so much smoother than games running at 24 fps?	[ "Live action movies naturally have motion blur. For CG films it's added in. This makes it appear smoother. Games can add it in, but at a performance cost. Many games don't because the developers decided the processing power would be better used on other effects, or to keep the frame rate higher. edit - That's only ...	[ "Your muscles are innervated by motor neurons - nerve cells that signal to the muscle to contract. To activate a muscle, the central nervous system sends a signal via the motor neurons and the motor neurons \"fire\" on the muscle with pulses. There are generally speaking three types of motor neurons which are class...
Why and how does a panic attack occur? Is it describable by words?	[ "Several months ago, I witnessed a phenomenon which can only be described as a \"chain panic attack\". Friend #1 had a panic attack which induced a panic attack in friend #2 and so on until it caused panic attacks for 5 different people. Has anyone else seen this before? Because I find it very difficult to comprehe...	[ "Can someone explain the difference between Dementia and Alzheimer's, please?" ]
Why do we feel "refreshed" after a shower?	[ "There was a recent reddit about the swim reflex claiming that when you get water on your face, your body's physiology alters and assumes you are underwater. Breathing, heart rate decrease. Calmness takes over (to prevent panic of drowning from taking over all energy in brain). Etcetera. I am not sure how valid thi...	[ "Someone correct me if I am wrong but it goes back to when we had much hairier bodies and when alarmed we as well as a lot of other mammals would puff up our hair to make ourselves look bigger. Think of how when you scare a dog or a cat it hunches up and its hair stands on end, same thing happens to us just we dont...
What does "thinness" or "thickness" of air imply and how does it happen and change?	[ "Thick and thin are referring to density, I.e. how much air is contained in a given volume. On planets like earth the atmosphere's density changes because gravity pulls it down. The air high in the atmosphere pushes down on the air lower in the atmosphere, compressing it and increasing its density. So, in places wi...	[ "It does! Water at 10 C is about 4 times as viscous as water at 90 C. Because the viscosity is so low at any temperature you can't see or feel the difference, but it affects the sound of pouring water in a way you can hear. _URL_0_ _URL_1_ Viscosity arises from the interactions between molecules, and for liquids is...
How did the Thai soccer team get trapped in a cave?	[ "Ya they walked in, then the cave flooded due to monsoon rains. Way out became blocked by water." ]	[ "HIPAA only restricts certain types of organizations from revealing health information (basically healthcare providers and insurers, plus their agents). The Hospital---without a release from the patient---couldn't say much of anything about a famous person's injury or treatment, but the coach or the team can. It is...
Why is there a prevalence of negative news broadcasted on the media on a common basis.	[ "\"Everything's fine, nothing happened\" isn't really exciting or interesting. Disaster and mayhem draw attention much more readily and thus increases a news station's viewership. More views, more revenue, and thus more negative news." ]	[ "commercialism. if you were happy with your old stuff, you wouldn't need to buy new stuff. all the designers and manufacturers come out with new looking stuff and market the old stuff as ugly and new stuff as pretty in order to make money. our tastes are hugely influenced by others." ]
Why does tuna have to come "in water" or "in vegetable oil?" Why can't I just get some tuna?	[ "Because it's seafood. Seafood does not last for long, and if you want to eat some tuna in Nebraska, you'll have to accept the current systems that we have for keeping it fresh enough to eat." ]	[ "I know what you're getting at. Space is pretty easy to see. We can see loads of it with the naked eye and small telescopes. We can see even more of it with really big telescopes and radiotelescopes and we can work out a lot of it using data and mathematics. On the other hand, the oceans are pretty big and pretty ...
If copper and its alloys are naturally antimicrobial, why aren't they used for cutlery?	[ "Copper is a very soft metal, so any knife would dull very quickly. Also copper is very reactive and will tarnish to a green patina. Not exactly something that looks great when you are trying to cut food. If you look at copper pots, the copper is on the outside, not in contact with food. The copper is there for hea...	[ "You could test it. E.g. cover yourself in grease and then shower 1) with water only 2) with water and the product. Compare results. That would be a (pretty crude) experiment, which is how we learn answers to those kinds of questions. Also you could compare two pieces of perishable food, one of them treated with th...
In the Bible, kings sometimes offer someone "whatever you ask, even up to half of my kingdom." Do we know of anybody who called them on that?	[ "In the Scroll of Esther (the Jewish text which details the events commemorated by the holiday Purim), King Achashverosh makes this offer to Queen Esther. I am not aware of any other instances in Jewish religious texts. Queen Esther asks instead for the King to spare her life and that of the Jews living in Persia."...	[ "It’s a lot more of a principle that’s been born out by data over a long time and many tests than something that justifies itself in explanation. It helps to just think of it as the “80/20 rule.” It’s supposed to apply universally, such as 80% of all events are triggered by 20% of all possible causes. But the most...
Why are eggs and sperm immune to the effects of aging?	[ "Eggs and sperm are in fact NOT immune to the effects of aging. Although a woman has a set number of eggs, the DNA inside those eggs are subject to degeneration, through processes like mutagenesis. The same goes for the DNA in sperm cells. One of the reasons it becomes riskier for a woman to have children at an old...	[ "Every time you make a copy of a cell, there is a chance for errors. For example when you photocopy a first print, it is pretty crisp and close to the original, but there are a few minor discrepencies. Now if you photocopy the copy, it gets more distorted, and so on until some letters get hard to read, it gets diff...
Why do we say "Redditor" instead of "Redditer"?	[ "The \"-or\" suffix is generally found on Latin-derived words, whereas \"-er\" is an English addition to basically any word we choose. So if the word originates from Latin, it is likely to use the \"-or\" suffix (of course, as with any language, there are some exceptions). It is very likely that Redditor was chosen...	[ "Some websites that update (webcomics, blogs, etc) have something called an RSS feed, which you can view in an RSS reader. With an RSS reader you can subscribe to sites with an RSS feed, so that you just have to go to your reader to see all the updates you care about and you don't have to go check them all individu...
How do people "hack" keys for software licenses?	[ "You can either hack the license generation scheme,. Or just hack the software. Somewhere in the software there's a line that says: Did the user input a correct license key? If so, proceed. If not, show license error and exit program. Change that piece so it always thinks you did enter a correct key." ]	[ "It's like you're driving a car down the highway and you need to replace the tires because they're old and worn out. You could engineer a really complicated system that would allow you to safely change the tires while you're still moving. Or, you could just stop the car, replace the tires, then get going again. ...
Why do we think verbally?	[ "I've been pondering this question too for a long time. I like to think that it's similar to our nervous system. You touch a hot stove, and a signal is sent to your brain that you're in pain. That transmission is nonverbal and instantaneous, but once you perceive it you have a verbal reaction. In other words, I don...	[ "CGP Gray has a pretty good take on this question. [This Video Will Make You Angry](_URL_0_) Time: 7:25 Subject: Transfer of ideas from person to person. It is a pretty awesome video if you feel like giving it the time to watch." ]
Why does the USA celebrate Cinco De Mayo, so much; compared to even Mexico?	[ "Americans love an excuse to get drunk, and the liquor industry loves excuses to boost sales. I'm pretty sure we make a bigger deal out of St. Patrick's day than Ireland does for the same reason." ]	[ "\"Just about everyone here\" Where is \"here\" for you? It sounds like your question's premise is based on a small sample set based on personal observation. Before your question is addressed, you should be making sure the premise is valid..." ]
Why is it a bad thing if America and Russia become friends?	[ "First off, Putin has acted in ways more akin to the Soviets during the Cold war than any leader since the fall of the USSR, such as invading Ukraine, having opposition politicians and journalists killed. Secondly, the evidence suggest it's not about being best friends or equal super powers with them, but Russia ga...	[ "Hi, I've approved the post, but just a note to you and potential respondents: this subreddit has a 20-year rule against discussing current events, so any answers will have to cut off at 1997. If you're looking for answers that can include 1998-2012, do consider x-posting elsewhere, eg. a foreign affairs sub like /...
Why are most Western Languages written using a common alphabet but more Eastern/African alphabets written using different sets of symbols?	[ "The Latin alphabet was used in Rome and its territories, and over the centuries Rome had a LOT of territory. Asia and Africa are different cases, but at this point a fair number of people in Africa use Arabic or French, or even Dutch/Afrikaans in South Africa, though there are still many peoples in Africa who spea...	[ "In symmetric cryptography, the same key is used to encrypt and decrypt the message. If Alice wants to send a message to Bob, she first has to send the message to Bob. This presents a problem - if the key is sent in plaintext, an attacker could intercept it and then use it to decrypt the message. If the key is sent...
Why doesn't Android support flash?	[ "You have it all wrong. Isn't not that Android doesn't support Flash, but that Flash stopped being developed for Android. This was Adobe's decision, NOT Google/Android." ]	[ "To put simply, infrastructure costs and up keeping requires a huge amount of money. Which cannot be covered by advertisements ." ]
How can a person die from pain?	[ "The sensation of pain is not lethal on it's own. You can, however, go into shock and then organ failure, which is definitely lethal. Otherwise, I assume the cause of the pain would be lethal in almost all cases." ]	[ "Yes, there is another way. It's called a cardiopulmonary bypass, and the machine basically takes over the function of the heart by pumping blood to the rest of the body." ]
Why are we weak right after waking up?	[ "Your body immobilizes you while you sleep. It does so chemically. The chemicals have to wear off." ]	[ "Dude, I typically experience the opposite, usually you're wiped out before making the trip back, and energized and active on the way there." ]
How do we know where to search for precious metals? How do we know that 100 ft underneath my yard isn't the largest gold deposit in the world?	[ "Certain rock types are more likely to have certain minerals than others, but for the most part they look around where they found some precious metals and hope there is more. Lot's of guesswork, gambling, and sampling. Maybe you find nothing, maybe you strike it rich." ]	[ "Have you ever walked into a room that had an odd smell, but three minutes later you couldn't really tell that the smell was there? Have you ever suddenly realized how hungry you are when someone passes by with a tasty looking snack? Have you ever had to pee, but you were busy doing something so it didn't really se...
Is it possible for the human body to recover naturally from cancer?	[ "Yes and it happens all the time. You don't notice because the cancer cells are so few in number. It's when the body can't keep up that most cancers develop into a tumor." ]	[ "Work is being done on getting spinal nerves to regrow and attach. So far its still in the rat testing stage but they are having good results. Also, there have been experiments with jumping the gap with electronics technology that are also showing promise. Turns out, if your can transmit the signals reliably across...
What causes your eyes to go grey when you die?	[ "Apparently this is linked to circulation/temperature of the inner layer of the cornea. _URL_0_" ]	[ "Analog TVs had a circuit called the [\"color killer\"](_URL_0_). It was designed to eliminate any color from the screen when B+W programming was being received. The B+W signal did not have a [color burst](_URL_1_) reference signal, and it is the absence of this color burst which triggers the color killer. Static m...
Why no major car brand will manufacture a small pickup truck?	[ "I work for a Nissan dealer. We market the Frontier, which can be had for as little as 20k. It does not sell. Largely, this is due to the fact that a truck, to be useful, must have a body on frame design and a bed. Both of these kill gas mileage, which is a priority for most cheap vehicle buyers. In addition, the c...	[ "Dealers carry insurance to pay for such things. If the accident is clearly your fault, or you were reckless/unduly negligent they could go after you for compensation." ]
The Venus figurines of the Upper Paleolithic are known for their voluptuousness to the point of looking obese. During this period, however, there is almost no way someone could have sustained such a large amount of body fat. How, then, did the idea/inspiration for these figurines come about?	[ "I'm curious as to why you say nobody from that time period coulf maintain that level of body fat." ]	[ "The foods one I can answer. We evolved to like high caloric foods because we needed the calories when we were struggling to survive. Thus fatty or sugary foods taste good to us because it used to be great to eat them. Well now it's too easy to overindulge and weve made processed foods that have way more fat or sug...
why does my cat come sit with me and follow me around when I'm ill?	[ "Take a paracetamol pill and check again in about 30 min when your body temperature is decreased. Cats like warm objects. But they can love you too... It may even bring a sparrow or a mouse to feed you while you can't hunt efficiently." ]	[ "Imagine your body is a phone. Not a Samsung Galaxy S56XL, just a regular one. You go and open 30 apps and the phone suddenly starts slowing down, right? Well, now imagine the common cold is a VERY consuming app for your cellphone, some kind of new Fortnite 2 game or whatever. Your body doesn't work as well when yo...
Why aren't any planes covered in dimples, yet every golfball is?	[ "The dimples drag reduction apply to really low speeds, like takeoff. Actually it's really low Reynolds Numbers but they're similar. At transonic speeds, where airliners fly, those dimples would disrupt the shock leading to potentially massive drag spikes. In addition, the increased stress on a wing around the dimp...	[ "Google doodles take a lot of effort to create, even the simplistic ones, and usually hope to serve the interests and audiences of multiple countries. So you have to understand even significant tragedies don't always get doodles (9/11 didn't get one this year either.) However, you're not wrong in that it's a littl...
Why is a computer keyboard set up the way it is?	[ "QWERTY was initially developed to help keep typewriters from jamming. Early models would jam if two keys were hit too quickly in succession. So people got used to it. Once the jamming problem was solved, you were still left with all the typists who learned QWERTY. So if you're a firm hiring typists you would sever...	[ "Long story short, we write it like we speak it." ]
If 'nothingness' can't exist, what fills the gap between electrons and the nucleus?	[ "Can you explain why you think it's impossible for \"nothing\" to exist?" ]	[ "When you drive, your wheels are always between you and the road. Does this mean that you do not move up and down with the road? (Negating the effects of your shocks) you will still feel the entire topography of the road as if you were in direct contact with it. To avoid confusion it is better not to look at the fo...
Why is human (and many other animals) faeces brown?	[ "Although your stool colour is influenced by what you eat, the brown colour is generally caused by bile. Bile is produced in the liver and channelled into the intestines via the gallbladder. Bile helps digest fats in the food you eat, and also allows the body to excrete bilirubin, a byproduct of the normal breakdow...	[ "Different things you eat have different densities. Dense things, like when you have a protein heavy diet, tend to sink. Less dense things, like vegetables with lots of fiber float. Also, depending on how fast it moves through you, different quantities of water are extracted in your intestines." ]
Why doesn’t Coke stain?	[ "I don’t know what you’re talking about. I can tell you for a fact that coke stains. There are still stains on the carpet in my parents house that can prove that." ]	[ "I found [this paper](_URL_0_) from 1982 that studied the virus 'survival' of influenza A and B on non-porous and porous surfaces. They found that, as you said, the viruses survived longer on the non-porous. They didn't dwell on this finding for long, but did mention that: > Both influenza A and influenza B viruses...
The state of nuclear physics/modeling?	[ "I can't discuss modelling techniques, but regarding your last question, the model of the nucleus is similar to the orbital model of the atom, except that the protons and neutrons each have their own energy levels. There's also the more rudimentary liquid drop model which is useful for figuring out the mass of a nu...	[ "There is no full life. Suppose I give you a really large number of something. After an hour, I take away half of that number. After another hour, I take away half of what remains. After another hour, I take away half of what remains from that. So after one half-life, I've lost half the sample. But the whole sample...
How is the evolution of animals such as bees and ants influenced by the low percentage of induviduals who can reproduce?	[ "When you're talking about the evolution of bees and ants you're essentially thinking of every colony as a \"superorganism\", with all the inhabitants operating as a single entity and reproduction occurring via queens and drones. The fact that ants can sometimes select a new queen complicates the model somewhat. Bu...	[ "Imagine a huge machine. You'll find screws, nuts, bolts, gear wheels, cambelts and whatnot. Each part has a purpose. If part A doesn't work, part B may not be functioning as well. Nature is way more complex. Animal A maybe a source of food for animal B. Animal B helps animal Z to survive via a long chain. If anim...
Please help me verify a fact/bet please. Did London/City streets in the UK grow significantly in height historically due to excrement and chippings constantly thrown on them? To the point where ground floors became basements.	[ "Cities and other places where people live do tend to grow upwards over time, though for reasons other than chips and excrement. [This thread](_URL_0_), in particular the top answer from /u/kookingpot but also the one from /u/alriclofgar, explain what happens in cities that have been in constant use for some thousa...	[ "Usually not. During construction at least, adding a basement is the cheapest way to add square footage to your home. Adding a second story to a home isn't as easy as it sounds - with a second floor, the first floor has to be engineered to hold up the weight of the second floor. Also, in some areas, basements are b...
Why/how university became just as well known for partying, sex and drugs as for educational purposes?	[ "i honestly have no idea why it is that when you put 50,000 teenagers on their own for the first time in their lives..they tend to have sex and party. not a clue." ]	[ "It's similar to the way 125% subprime mortgages spread (without getting into the debate about whether that caused the recession) - you get a few groups who think a similar way, with broadly the same ideas, motivations, worldview, that sort of thing, and when one of them comes up with a policy that fits those ways ...
Why do some people float on water easily when others a similar size can't?	[ "We're mostly water, so it doesn't take much either way to make us dense enough to sink, or a little more buoyant to float. I found out when I was little that I was almost neutral, and could float if I filled up my lungs, but would sink if I emptied them, scaring the lifeguards at the pool, so it's a pretty close b...	[ "You're eating less than you think, and he's eating more than he claims. He probably does minimal exercise at the gym, and downs a couple of sugary gatorades while he's at it. Both of you start a food diary on _URL_0_ (or anything similar), compare after a few days. You'll see what's really up." ]
The "Pause/Break"-button next to the "PrintScreen"-button on your keyboard. Every PC keybard has one, why doesn't it ever function?	[ "its only used at very specific times, and unlikely ever needed for the average user _URL_0_" ]	[ "The US Board on Geographic Names oversees this, and makes up rules to keep spellings consistent. For example, it was this agency which decreed that all the various place names ending in -borough and -burgh should all instead be spelled -boro (with Pittsburgh being the honourable exception): that way, nobody gets c...
Why has samurai swordfighting (kendo/kenjutsu) consistently survived while European knightly swordfighting has little practitioners?	[ "Because Japan tried to turn back the clock/restrict progress and western influence for 300 years, while Europe continued to develop technologically (both with guns and swords). By the time the world was wealthy enough to pursue martial arts for sport, relatively modern guns had greatly reduced (but not eliminated)...	[ "Many missions do use multiple slingshot encounters (aka \"Gravity Assist Maneuvers\"). If I recall correctly, the Rosetta mission performed two Earth GAMs and a Mars GAM. Cassini performed two GAMs past Venus, one past Earth, and another at Jupiter. However, this takes time. In order to pull off the double-earth s...
Why didn't all the matter and antimatter cancel each other out after the big bang?	[ "That, currently, is a mystery. It is hypothesized that some interactions favour matter over antimatter (called charge parity violation), and experiments at the LHC (LHCb) and elsewhere are testing this." ]	[ "I've thought about this quite a bit, and Carroll is absolutely right in saying that if there is an effect carrying away information - which obeys the laws we are used to - then we would be able to detect it. The problem is that if you really want to believe in god or the afterlife or whatever, then you can just s...
Does old blood get phased out of circulation after a certain amount of time or does it circulate until a laceration?	[ "Blood is continuously filtered by the body, and the specific mechanism depends on which part you're talking about. The liquid fraction of the blood is continuously filtered by your kidneys, for instance, which filter out waste products to be disposed of through urination. There is no concept of \"old\" vs. \"new\"...	[ "They distribute it to banks, so when you get paid (let's say your employer deposits your pay electronically) and you withdraw some of it in cash, sometimes that's brand-new money they're handing you." ]
Do tides affect a sailors viewing distance on the open sea? If so, how much?	[ "Negative. On the open sea, it's very difficult to judge viewing distance. Takes a long time to learn, lots of practice, and lots of standing duty. I never was any good at it. I would spot something in the distance, report it, what direction it's in. The radar guys would find it and be able to tell the distance. An...	[ "[This post](_URL_0_) has links for pictures of all the Apollo landing sites. These pictures were taken by a satellite around the moon. It's essentially impossible to take pictures of these sites from Earth. Kind of hard to believe at first, but it's true. You would need an unbelievably large telescope because the ...
What are scientists doing to combat drug-resistant bacteria and superbugs?	[ "One area gaining increased interest recently is study into bacteriophages. These are organisms that have evolved to hunt bacteria, including those that affect us. Even drug-resistant bacteria is susceptible to the power of evolution and predation. The challenge is that you have to identify positively the actual di...	[ "This does not quite fit the bill of \"rival country\" but in 1989, a self described \"ecoterrorist group\" known only as \"The Breeders\" took credit for the recent infestation of California by medflies, which began destroying crops. Opinion is divided today as to whether it was a real attack, an out of control pr...
If I inhale different gases, like you do with helium, will my voice change?	[ "The gases should be reasonably non-toxic. Sulfur hexafluoride gas is often used for demonstration purposes. SF6 is about 5 times more dense than air, and is quite inert, though less so than helium. Interestingly this doesn't actually change the fundamental pitch of your voice, as that's solely determined by the si...	[ "It varies, but not much individually. The problem is when everyone does it. It's kind of like why you're taught not to pick a flower from a garden when growing up. You alone, picking one flower, is not going to be noticed, it's not going to affect the plant or garden overall, but if everyone picks just 1, very s...
Other than its touted face-melting properties, what other ways did the Nazis weaponize the Ark of the Covenant?	[ "The Nazi's never had a chance to uncover additional applications. I'm told it's still being worked on in the US by top men. Who? Top. Men. Source: _URL_0_" ]	[ "Awesome question, you’re right that the research about this kinda sucks. If you are good at interpreting/understanding research articles then check this out, if not then I’ll cover the details below so don’t worry: _URL_0_ Generally, research of this nature is done using model organisms, in the case of this study...
Whats the different between AC and DC voltage supplies?	[ "AC Stands for alternating current, meaning that the charges are moving in alternating directions (moving charges = current) while for direct current (DC) they are moving in in one direction. AC currents are generally speaking easier to generate and transmit and can be transformed. This is why AC is what is comi...	[ "One of them shits on the poor and tells them to dodge. The other shits on the poor while pretending it's sending gifts." ]
Can someone explain the Laplace operator in terms of surface integrals?	[ "By the Laplace operator I'm assuming (based on the context) you mean the divergence rather than the Laplacian given by \\sum_i d^(2)/dx_i^2 . Gauss' law certainly has an equivalence between the differential and integral form that follows from the divergence theorem and tells you that divergence of the electric fie...	[ "The SEIR model is one way of projecting how many individuals in a population are Susceptible Exposed Infected and Recovered when considering an epidemic that allows an infected individual to immediately transfer the parasite to another individual. Some parasites have latency periods where an indiv...
If i stay up late and have work/class in the morning, at what point (if any) is it better for me to stay up instead is sleeping?	[ "one REM cycle is an hour and a half. it takes an average of 15 min to get to sleep. therefore, if you have 1h 45min, you can take a nap and feel well rested. Edit: source: Article on sleep cycles: _URL_0_ Also note these are averages, individuals may have different varying REM cycles, and varying lengths of time ...	[ "Good posture generally uses muscles to hold you in a certain position, requiring effort. Slouching basically means relaxing these muscles and letting the weight of your body rest on ligaments and joints. It’s always easier to not put in effort. Also, slouching is only really bad if you do it for a long time with ...
Do different isotopes of an element exhibit different Bremsstrahlung?	[ "The spectrum of Bremsstrahlung cannot \"shift,\" except in its intensity. Bremsstrahlung is \"braking radiation\" and depends only on the charge of the atomic nucleus. A given electron interacting with the nuclear charge can be slowed down by any amount, producing a spectrum of radiation essentially from the acc...	[ "There is [this] (_URL_2_) famous picture taken on the roof of the reactor. The radiaton level is so high that the workers were allowed only 60 seconds on the roof. ~~The white streaks at the bottom of the picture are caused by radiation leaking through the camera body (not the lens). There is a film advancing cog...
If a meteorite from another solar system landed on earth, would it be obvious after an analysis of its composition that it didn't originate in ours?	[ "Yes it would be obvious because their isotope ratios would be completely absurd. We have tiny grains that we think are presolar (i.e., formed before the sun) and this would fit your criteria. _URL_0_" ]	[ "It depends on how close the explosion was to ground level, and how big it was, how much protective gear you are wearing, and how long you would be staying (are you coming out of hiding just to leave the area, or are you planning to live there?) TLDR: Bigger warheads, and detonations that are closer to the ground ...
Is it in our DNA to enjoy music?	[ "I just finished reading a book called This Is Your Brain On Music. I can recommend it if you want to know more about why music exists, why we enjoy it etc. As for answering your question, I am the polar opposite of an expert on the subject but one of the strongest theories in the book was that music kind of piggyb...	[ "Because we are very close relatively speaking in terms of evolution. We are, in a broad sense, not \"very\" different to each other. That's why it's hard. For example, Nicotine (and caffeine) were created by plants to attack insect \"brains\" and those molecules also bind to humans brains. But it can be done!, one...
Why Don't Identical Twins Have The Same Personalities If Their DNA Is The Same?	[ "Because personality isn't molded exclusively, or even primarily, by DNA. It is molded by life experiences, interactions with people and things, by chance events and strokes of luck." ]	[ "The descriptions in the link provided seem to exemplify something called the [Barnum effect](_URL_0_). Note how very few of the descriptions will contradict each other; every description can apply to every person with a fair amount of accuracy. Within the descriptions, though, contradictory statements appear fairl...
Why are the numbers on an analog radio dial irregularly spaced?	[ "Actually it's not logarithmic, it's closer to a 1/x relation since what you turn is not a resistor, but a variable capacitor. A capacitor and an inductor are used in the tunning circuit attached to the antenna. But log scales are indeed used in frequency plots since it better represents the behavior of systems." ]	[ "Basically if you plot the image density versus integrated energy on a pixel, you will find that no system is perfectly linear. Even the time of exposure (shutter speed) can affect the results. Film was especially bad in this respect. And lead to things like [\"Black lightning\"](_URL_1_) on photographs. Caused by ...
How are skyscrapers from, say, the early 1900s safe given the limitations of technology back then?	[ "Well partly because people keep an eye on buildings to make sure they're still good every now and then, repairing and renovating as needed, and partly because steel girders and concrete are quite sturdy." ]	[ "The crushing pressures in the ocean among other things. And how would you remotely operate it? with miles of umbilical cabling or with radio that can only penetrate so far?" ]

Subsets and Splits

No community queries yet

The top public SQL queries from the community will appear here once available.