id stringlengths 5 6 | input stringlengths 3 301 | output list | meta null |
|---|---|---|---|
8e08ee | why is integral of velocity equal to displacement? | [
{
"answer": "An area under a function is the definition of an integral.\n\nOr think of it this way: you have a height of a function on a graph. The slope of the function indicates if the height is getting bigger or smaller. Ex: if your function is a line with positive (upwards) slope that means the height is ge... | null |
ettsci | how exactly is a person's phenotype determined? does every gene in our dna influence our phenotype? | [
{
"answer": "So to start, there are dominant and recessive genes. You have two sets of every gene (one from each parent), so when one is dominant and the other recessive, the recessive gene isn't contributing anything (in reality this can be a bit more complicated). \n\nThen there's \"non-coding\" DNA, sometime... | null |
4tso90 | how do laser range finders work? wouldn't the laser bounce away when it hits the target? | [
{
"answer": "if there is a visible dot on the surface, than atleast *some* of that light is being reflected back at you.\n\ndoesnt even need to be visible to you, as the device is going to be far more sensitive.",
"provenance": null
},
{
"answer": null,
"provenance": [
{
"wikipedia... | null |
3ak1u6 | The Anglican Church: Ancient Institution or Created by Henry VIII? | [
{
"answer": "Not to any greater a degree than in other regions of Europe. The church in England, in all its guises, has possessed national character, expressed through saints' lives, relics, and architecture. In terms of a church hierarchy the Pope was the official ruler of the English church right up until Hen... | null |
4plcsp | Whats stopping us from using H2O electrolysis as energy storage for solar arrays? | [
{
"answer": "People have been talking about the \"Hydrogen Economy\" since the 70s, but there are some significant issues that have plagued it, although a lot of smart people are working on the problems.\n\nThe first is how to store the hydrogen. First off, it is extremely flammable (think Hindenburg), and whil... | null |
6p4576 | how did people who found other people who speak a previously unknown language translate it to the point of perfection? | [
{
"answer": "The same way children who previously don't know any language learn it to perfection: someone learns the unknown language. As soon as you've got a few people that can translate, the accuracy of it snowballs. ",
"provenance": null
},
{
"answer": null,
"provenance": [
{
... | null |
7te4qe | What happened to General Montgomery after Operation: Market Garden failed? | [
{
"answer": "tl;dr - Almost nothing changed in Montgomery's situation, he continued in command of the 21st Army Group which included most (all?) of the Commonwealth combat divisions, and several US units, until the end of the war.\n\nFor a while since the invasion of Normandy Montgomery had been pressing for Ei... | null |
am9ewk | Are there any good online sources on the Opium Wars? | [
{
"answer": "It is difficult to prove a negative, but from my experience the answer is 'basically no, unless you count output on this subreddit.' While academic consensus on the Opium War has swung decisively in the revisionist direction, most online articles continue to exaggerate the impact of the war and fai... | null |
805q7a | How were the Persians able to field so vast armies? And what are the logistics behind such a monumental effort. | [
{
"answer": "Hi! You might be interested in [this post](_URL_0_) I wrote recently about the Persian army numbers you find in sources like Herodotos and Xenophon. In short, these numbers are not reliable historic facts, but estimates that were meant to look plausible enough not to undermine Greek authors' credib... | null |
qsbax | Is there a reason that the letters towards the end of the western alphabet (the last five in particular) are less frequently used than the others? | [
{
"answer": "keep in mind that they are less frequently used *in english*. spanish uses y and z quite a bit. french uses x all the time. italian also uses z a lot. so while they might not be common letters in english, they are common in other languages",
"provenance": null
},
{
"answer": null,
"... | null |
2l9m2s | what are the us voting for today? | [
{
"answer": "Congress gets voted in more often. The House of Representatives(like your House of Commons) gets completely re-voted every two years, so they're all up for election, and the Senate(vaguely similar to an elected House of Lords) is on staggered 6-year terms, so 1/3 of them are up for election. Also, ... | null |
3jn9fw | expiration dates for painkillers (details inside) | [
{
"answer": "You are looking at date Filled vs date expired. Not date manufactured vs date expired. These drugs are created in large quantities but that doesnt mean they all get distributed at the same time. So the ones you got in 2013 and the ones you got in 2015 could have all been made in 2013. Drugs do exp... | null |
u72k2 | To what extent is modern US law derived from Roman law? | [
{
"answer": "In *The Common Law* Oliver Wendell Holmes looks at similarities between Roman and common law but I can't remember if he establishes that any common law doctrines were derived from, as oppose to merely resemble, Roman doctrines.",
"provenance": null
},
{
"answer": "Louisiana has a system... | null |
15wbgz | why do we say "on the plane", "on the train", but "in the car"? | [
{
"answer": "Presumably in this case because a car is ours, so we're *in* our possession.\n\nThe others are open to the public, so we're *on* the service.\n\nAt least, that's how I assumed it works.\n****\nEdit: Giraffebacon has an awesome theory that it doesn't depend on possession, but **control**. If you con... | null |
2iysqh | Light splits in all colors, so is light just a ray of photons with different colors? | [
{
"answer": "Yes. You can think of sunlight for example as a very large stream of photons of a variety of colors (wavelengths). For sunlight, the distribution looks like [this](_URL_0_).",
"provenance": null
},
{
"answer": "Yes! \n\nWhen light splits (like when you pass light through a prism) it is ... | null |
740d9n | How did the free peasant republic in Dithmarschen in the 15th and 16th centuries actually function? | [
{
"answer": "I've basically covered this on a podcast, so let me start with that.\n\nYour answer is in this episode:\n_URL_0_\n\nThat show was actually about the region south of Dithmarschen. But the cause of their freedom was the same:\n\nIt's swampy and tough economics there. There were NOT actually independe... | null |
960p8g | Catharism was a militant heresy that gained strong support in Southern France in the 13th century before being suppressed in the two decade Albigensian Crusade. Two or three centuries later, Southern France again became a bastion of militant religious heresy with French Huguenots. Any connection? | [
{
"answer": "I've asked a few questions about Cathars on this sub, and it seems that a lot of historians question whether the Cathars even existed at all. \nYou might want to look at this answer about Cathars from u/sunagainstgold\n\n_URL_0_\n",
"provenance": null
},
{
"answer": null,
"provenanc... | null |
5kmkqg | why is the tachometer (rpm counter) so large in a car's dashboard (as large as the speed dial)? how is the information useful to the average driver? | [
{
"answer": "Great if you drive a manual. Tells you if your revs are too high and you need to shift up, or too low and you need to shift down. No idea why you'd want one on an automatic. ",
"provenance": null
},
{
"answer": "It's mostly useless, even for a standard transmission. If all you drive is ... | null |
gn2uz | Would you hear an explosion in space from Earth/Endor? | [
{
"answer": "IANA explosion expert. But being historically inclined, I remembered that there have been a few nuclear explosions in the very high atmosphere, and so I went looking for information there. You can find more information than you want [here](_URL_0_) (pdf).\n\nPage 21 says they heard no sounds from... | null |
3gbdc4 | Were there any universally agreed upon "rules of engagement" for hand-to-hand combat in pre-firearm era battles? | [
{
"answer": " > I know some of the bloodiest combat happened after formations broke\n\nThe bloodiest combat would happen after the formation of *one side* broke, and almost all of the blood would come from them.\n\n > but were there rules to how you fought with the enemy, i.e. one-on-one.\n\nDon't do it becau... | null |
bx3c4t | how does the brain create brand new words? | [
{
"answer": "Creativity. You could have merged together \"rustles\" with \"cramp\" or just added a c to the beginning because it was amusing to 8 year old you. Or you just randomly thought of it and it stuck.\n\nFor an example not involving language, imagine a purple creature the size of a chihuahua with a hand... | null |
1ri567 | modern militia purposes? | [
{
"answer": "The are a remnant of an earlier time. The truth is they aren't all that important, but many states feel strongly about maintaining their right to have one (Which is the true point of the 2nd Amendment).\n\nIn theory, in the event of an invasion or the like they would join the fight. The thing is,... | null |
5bmvxf | In theory and practice, how did the fascism of Italy and Austria differ from the fascism of Nazi Germany? | [
{
"answer": "Italian Fascism was a hybrid ideology in practice: it drew elements from socialism (state interventions in economy, an emphasis on welfare policies like public housing schemes, state sanctioned free time activities), liberalism (a tendency to favor industrial and financial interests), totalitarian ... | null |
9i96y7 | why and how do electronic devices draw only as much current from a power source as required in that very moment? | [
{
"answer": "Everything draws only as much as it needs.\n\nElectricity flows a little like water, for ELI5. You open the radio a little when you need just a little, or all the way when you want a lot.\n\nYour television, to pick one, draws just a little power while it waits for you to turn it on. Then when it's... | null |
vcq00 | Is vaporizing really healthier than smoking? | [
{
"answer": "It's healthier since you do not inhale the ash and carcinogens that are present when substances are burned. Smoking involves burning the weed/tobacco, thus chemically carcinogens are formed. Vaporizing relies on heating the substance to a state where certain chemicals are released and ingested via ... | null |
1xig8h | Light travels so fast that, for all intents and purposes, it's either there or it's not. So what am I seeing when I turn a light off and slowly watch the bulb or housing dim and glow faintly in the dark? | [
{
"answer": "If this is a lamp you \"burn\"; one with a filament or an arc-lamp. These work by heating an excitable gas inside the bulb, that gas releases light. That gas and filament are pretty hot, and don't cool instantly, just because you've turn the power off. \nI've seen this with CFLs and oth... | null |
199scy | How does Gesture Recognition work? (Computing) | [
{
"answer": "There's a lot of techniques for this, and it's an active research area in man-machine interaction and artificial intelligence. If all you have to do is write an introductory section, look up some survey or review papers on the field. [This](_URL_1_) ([PDF](_URL_2_)) is a good one, as is [this one](... | null |
1y0e72 | how significant was finding the rosetta stone? | [
{
"answer": "From an archaeological and histological perspective, massively significant. Before the discovery of the Rosetta Stone we were unable to decipher hieroglyphics from ancient Egypt. The Rosetta Stone had 3 blocks of characters on it, the top was Egyptian Hieroglyphics, the middle was Demotic script an... | null |
1l0sbi | how were cameras allowed inside of concentration camps? | [
{
"answer": "Well the Nazi's documented and kept thourough records of the concentration camps. plus the vast amounts of scientific literature garnered from the medical experiments performed on prisoners has proven very usefull in modern medicine",
"provenance": null
},
{
"answer": "A lot of what wen... | null |
br0njb | how does the price of the dollar affect the economy of foreign countries? | [
{
"answer": "If the price of the dollar (exchange rate) is low, it means that countries with a different currency can buy the same US products for less money. Example: company A sells 100 products for 100 USD to a foreign company B. Now the exchange rate falls and 100 products now cost 95 dollars. This might lo... | null |
4hw4mf | what stops the bones in your foot from ripping through your flesh and skin with all the pressure from walking and running? | [
{
"answer": "The bones aren't that sharp and your skin isn't that weak. That's really the long and short of it.",
"provenance": null
},
{
"answer": "Where your bones bear on the outside world they have pads - your heel, for example, has quite a thick pad of for want of a better word, gristle.\n\nEls... | null |
2b1grt | on reddit, why are links to youtube, sometimes written as "_url_0_" (dot after u, before b), next to the title | [
{
"answer": "Because that's what youtube gives you when you click the \"link\" option from the \"share\" box. It's designed to save a few extra letters for stuff like twitter where that matters.",
"provenance": null
},
{
"answer": "_URL_0_\n\nIt's just a way to make your link appear shorter. If you ... | null |
4kw2is | Did the Persians really have massive casualties at the battle of Thermopylae? | [
{
"answer": "They suffered heavy casualties *but* that's relative to the losses incurred by a winning side. The thing with ancient and medieval battles is that the majority of losses in a battle were suffered by losers when they routed - the winners could cut them down as they fled. The actual losses on the win... | null |
7323do | physical nature of genes. | [
{
"answer": "DNA is a string of nucleotides. some of it codes for proteins, some of it controls the expression of genes, some of it is junk. All of it looks the same, it's the same four amino acids in billions of different patterns.\n\nSections that translate into proteins have special bits at each end tat are ... | null |
5qzj1n | Clothing in Archaic, Classical and Hellenistic Greece | [
{
"answer": "Clothes in ancient Greece are basically just a variety of rectangles. The most basic garment is a chiton and that is essentially piece of cloth folded around the body in a U shape. The opening fell on one side of the body, under the arm. The garment is then pinned on the shoulder and tied at the wa... | null |
axn6g7 | How did amber encapsulations happen? | [
{
"answer": "It probably landed on this poor guy or he fell into it. The weight of the Amber is irrelevant, once it's encapsulated the antenna have plenty of time to spring back before the Amber hardens. Bugs die of oxygen deprevation relatively quickly. Amber is not this pretty in nature, this was almost defin... | null |
9sgnxo | if 52*7 is 364 where do we get our extra day to make a 365 day calendar year? | [
{
"answer": "52 is just a rough enough guide to how many days there are in a year but if you add the days of each month, you'll get 365.",
"provenance": null
},
{
"answer": "There are 52 FULL weeks in a year, and 365 FULL days. Those extra fractions make the extra day each year and the extra day eve... | null |
2wkwh4 | Can something be genetically modified "on the fly" and see results in a (relatively) short period of time or is that something that has to be done before birth? | [
{
"answer": "You can't just re-engineer a somatic cell (non-sex cell) and expect to see changes in the whole body just because of that one change (all of its daughter cells will be different, but only them). You can re-engineer somatic cells with a virus (a.... retrovirus?) which actually changes the DNA of a c... | null |
zzd7f | How can I make water boil faster? | [
{
"answer": "Start with hot water",
"provenance": null
},
{
"answer": "change your elevation",
"provenance": null
},
{
"answer": "If you aren't already doing this, putting a lid on the pot brings water to boil much more quickly. The salt question is addressed [here](_URL_0_), essentiall... | null |
p3ou9 | how to legitimately change your last name? | [
{
"answer": "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 pref... | null |
114kfu | Would there ever be a way to dissolve plaque without damaging teeth? | [
{
"answer": "Not quite, dental plaque is a biofilm formed by bacteria, not a crystal. Certainly not made of enamel. As for alternative methods to remove it, I'm not in the field, so I not sure what's available.",
"provenance": null
},
{
"answer": null,
"provenance": [
{
"wikipedia_... | null |
1tzb5w | Did medieval armies have NCO's or something like a centurian to help lead troops into battle? | [
{
"answer": "For the albeit limited examples of the Holy Orders, the Templars had Sergeants. [Literary Source here](_URL_1_), as did the Hospitallers. [Additional source here, ](_URL_0_) \n\nI do not know about the Teutonic Knights. \n\n",
"provenance": null
},
{
"answer": "Your officers and NCOs w... | null |
3qn8vd | why do some radio stations (usually more popular or "mainstream ones) raise the pitch or speed up the songs they play? | [
{
"answer": "Just so the song is shorter. Sometimes they will cut sections out of songs too. What comes to mind is when Metallica released death magnetic back in '08.\n\n[The shortest song is 5 minutes, and the next shortest is 6:25](_URL_0_)\n\nI forget which songs they were always playing exactly. \"The da... | null |
20dxn5 | "for every action there is an equal and opposite reaction". is there anything in the universe where this isn't true? | [
{
"answer": "Well, sure. There are all kinds of situations of one thing \"acting\" on another without getting \"acted\" on back, because \"acting\" is not a scientific word. That definition of Newton's Third Law is very vague and actually has no real meaning. A better definition is:\n\n\"For every force ther... | null |
3gyt91 | Why did the silk road and the other primary east-west trade routes cross through the desert instead of going north through the Eurasian steppes? | [
{
"answer": "It's important to remember that very few (if any) traders travelled the entire length of the silk road- it was more like a relay of different traders.\n\nThe central Asian deserts were already populated by nomadic people with a long tradition of trade, which facilitated the establishment of the gre... | null |
12g9ax | What obscure folk tale/s from your area of speciality might have rivalled Grimm's fairytales if they had been helped to spread among Western culture at the right time? | [
{
"answer": "The tales of Hershele of Ostropol are quite entertaining. They're relatively well known amongst some Jews and Ukrainians.",
"provenance": null
},
{
"answer": "I'll refer you to [this story](_URL_0_), which isn't even very well known among Russians, I don't think.\n\nThere's also a hagio... | null |
2a78y0 | WW2 - U-boats vs the D-Day invasion fleet | [
{
"answer": "It was infeasible because it was suicidal. The invasion convoys were escorted by several dozen destroyers, frigates or other escort ships with Anti Submarine weapons on board. The RAF coastal command flew numerous patrols over the English Chanel, Particularly ... | null |
2qqx2h | how /r/adviceanimals isn't a default sub even though it has more subscribers than /r/explainlikeimfive? | [
{
"answer": "It used to be, and redditors got tired of the same misused full-of-shit memes clogging the page. I'm guessing reddit admins did as well.",
"provenance": null
},
{
"answer": null,
"provenance": [
{
"wikipedia_id": "53910445",
"title": "Location-based recommenda... | null |
42lgk0 | how much money is there in the world in total and how's it measured? | [
{
"answer": "For a while counting is the simplest way to measure money. I say that because eventually it gets tricky.\n\nThere is of course the cash money. Money in our pockets and in the cash drawers of registers. That is the smallest amount. It is counted as it is produced and banks count it as it comes in.\n... | null |
1vno20 | why you can get a heart attack if you're shocked or scared. | [
{
"answer": "An increase in heart rate and/or blood pressure can dislodge fatty deposits in the arteries that feed the heart. If they break off they can block the supply of blood to parts of the heart. That's a heart attack. The heart muscle then begins to die. ",
"provenance": null
},
{
"answer... | null |
2ofydt | Why did French revolutionaries prefer an emperor to a king? | [
{
"answer": "In 1799, the French Directory was a corrupt political machine that used war to divert attention away from problems within France (such as how corrupt they were) and using war to gain funds for both the government and themselves. The coup of 18 Brumaire would drive the corrupt Directory away and pla... | null |
1foogw | What is the most significant historical artifact that has been stolen or appropriated by a state after rediscovery? | [
{
"answer": "I can't say that this was a re-discovery, but one of the more interesting examples of something like this was when Texas revolutionists attacked and killed General Santa Anna and his army. They stole his wooden leg, and it was held in a museum in what I believe was Illinois. Apparently, Mexico hate... | null |
1gte4l | What makes gecko feet walk on whatever surface? | [
{
"answer": "The idea is that Van der Waals force comes into effect as the \"hairs\" on the bottom of gecko's feet are so small.\n\n\nWiki has a good explanation of what this force is:\n > \"The van der Waals force is the sum of the attractive or repulsive forces between molecules (or between parts of the same ... | null |
dxmbcq | 5: why is it so hard to replace plastics with another material with similar properties? | [
{
"answer": "Cost: plastic is extremely cheap to produce (also to recycle), currently nothing as cheap exists so companies will keep using what makes them the most money. \n\nProperties: there actually aren't many materials with similar properties: \n- recycled/compostable plastics aren't as maleable and mess u... | null |
2rgt4a | why farmers give their cows nose rings | [
{
"answer": "It's to attach a leash to. It's very painful for a cow to pull against a lead when it's attached by the nose, so this allows humans to walk them around. If it were around their neck, there's no wah you'd get them to move unless they wanted to.",
"provenance": null
},
{
"answer": null,... | null |
4ajrel | how does mental illness start? | [
{
"answer": "It's a large category, including different illnesses with several different causes. These can include:\n\n- Chemical imbalances\n- Traumatic experiences\n- Inadequate care during the first 3 years of life\n- Brain injury\n- Genetic abnormalities\n- Long-term stress",
"provenance": null
},
{... | null |
9l0yl8 | Why doesn't the water from the river mix with the water from the sea? | [
{
"answer": "It is mixing. Just slowly and in places you can't see. The different densities, salinities and turbidities are very large so it will always take a long time to mix. Furthermore both bodies of water are being replenished so the mixing is counterbalanced. It is likely you are seeing the top of a less... | null |
fdhmsz | I don't understand how a serf and a slave in Medieval Europe were different? Was serfdom just slavery with extra steps? | [
{
"answer": "Serfs were a bit similar to slaves, but a slight bit more well off. While slaves were considered the property of their owners, serfs were not. And while they did not live the luxurious lifestyles of those they served, they still had their place, and had their limited rights (even if these rights ma... | null |
4ti7z2 | why does it mess up my counting when someone starts saying random numbers | [
{
"answer": "It's not just counting which is effected by other people talking. A similar experience can be had when someone else talks to you about a similar topic at the same time as you try to speak (it's often used as a demonstration of what it's like to live auditory hallucinations). Sadly I can't find a vi... | null |
6k90nb | How did the Romans communicate their laws to newly conquered, non-Latin speaking territories? | [
{
"answer": "I'm going to speak in broad and general terms here, since you've asked a question that concerns a wide area both geographically, as well as temporally and in terms of existing, previous legal practices (conquered Greek or Hellenistic cities, f.e. would have their own extensive bodies of law, while ... | null |
2xwfo9 | What were the most sought after professions in the Ancient and Classic era? | [
{
"answer": "Could you please specify more exactly what you're interested in? Antiquity encompasses a period of several thousand years, with myriad peoples and cultures interacting with each other for every moment of that time. Depending on time and place there are vastly different cultural and social attitudes... | null |
153rk4 | is there an actual quote from bible that condems homosexuality? | [
{
"answer": "It depends on what you believe 1 Corinthians 6:9 says\n\nThe Apostle Paul warns people against being \"arsenokoitai\" in the original Greek language text. Arsenokoitai were male shrine prostitutes that claimed to sell religious ritual sexual experiences.\n\nSome people believe the sin of the arseno... | null |
afzqqn | how do you get four first degree murder charges from one death? | [
{
"answer": "This is a case of 'throwing everything at the wall and seeing what sticks'.\n\nOr to put this another way - if you really piss the government or wrong person off they can really fuck up your life.\n\nNormally if you punch your girlfriend that's one count of domestic violence. But if the prosecutor ... | null |
a6w7zv | why do foreign names get spelled and pronounced differently in english? | [
{
"answer": "Because they have different origin languages. English is Germanic in origin, converts semi-ok to Romanic languages but not really. Nordic languages have different letter sets, and the Chinese has different inflections on syllables, makes its tough",
"provenance": null
},
{
"answer": " ... | null |
3bvb0b | What is the actual rarity of male calico cats? | [
{
"answer": "It's a surprisingly complicated question as there's more than one way to get a calico/tortie male cat, including mutant coat patterns that look like calico but aren't produced by the same genes that produce a calico pattern in females. As such, there's no simple answer for \"how rare\".\n\nMore in-... | null |
2e9yc3 | why does starting task manager when my computer is frozen seem to unfreeze it? | [
{
"answer": "Task manager has top priority, so if any other program is hogging up the computer in an endless cycle you can force it to shut down.",
"provenance": null
},
{
"answer": "Well, I can't say the same for my computer...\n_URL_0_",
"provenance": null
},
{
"answer": "Context: Task... | null |
5n6daw | what's the deal with yellowstone? | [
{
"answer": "Yellowstone National Park sits over what is known as the Yellowstone Caldera. This is the mouth of what's called a supervolcano. There are many predictions online on what would happen if the supervolcano erupted. [Here is one](_URL_0_).\n\nThe worst part, other than the immediate effects is such an... | null |
1ua3k7 | why do people get diarrhea when they are dehydrated? | [
{
"answer": "It does, and it's responsible for quite a lot of deaths annually in less developed areas.\n\nThe mechanics of diarrhea are not your body having too much liquid, but rather the balance of things dissolved on one side of your colon versus the other being off. This can happen even when you're dehydrat... | null |
m5cum | What is the best scientific paper you have read? | [
{
"answer": "Francis Crick - Molecular Structure of Nucleic acids(DNA)\n_URL_0_\nGreat paper, and very short!",
"provenance": null
},
{
"answer": "I would have to go with [The Hallmarks of Cancer](_URL_0_). (pdf [here](_URL_1_)).\n\nIf you have ever wanted to know how cancer works, this is the pape... | null |
eqs5re | why are other standards for data transfer used at all (hdmi, usb, sata, etc), when ethernet cables have higher bandwidth, are cheap, and can be 100s of meters long? | [
{
"answer": "You had the misconception of ethernet cables having higher bandwidth. That's where your root of your confusion.",
"provenance": null
},
{
"answer": "USB cabling and receptacle buses are cheaper than ethernet cables.\n\nUSB has greater port density, and will fit cleanly into thinner form... | null |
2i4ze3 | how do the moon's phases work | [
{
"answer": "The bright part of the moon is simply light reflecting off the sun. So the phase completely depends on the angle between the sun, earth, and moon. So you'll notice on a night with a full moon, the moon is approximately on the complete opposite side of the earth. During a new moon, it's approxmiatel... | null |
3x37yd | what is so special about the blu-ray format? | [
{
"answer": "Blu Ray isn't a type of video. It is a type of data storage system.\n\nBlu-Ray just uses lower wavelength (bluer) light in the laser it uses to read the disk when compared to a DVD. This lets the system read smaller spots on the disk. The ability to read smaller spots means that a disk of a given s... | null |
f12kb | I've always wondered: if I am in an airplane that is traveling JUST under the speed of sound, and I sprint down the aisle, would I break the sound barrier? | [
{
"answer": "No because the air that you're in is moving as fast as you are so your person is never near the speed in its immediate surroundings to break the sound barrier.\n\nNow if you were on the wing or top of said aircraft somehow and could run against the wind, I hypothesize that you would break the sound... | null |
20gj0v | Can a beam of light bend if the source rotates or moves in the same way water does from a rotating sprinkler? | [
{
"answer": "I am as far from an expert on this subject as you can get, but I'm pretty sure that once water or a laser beam, or any other sort of \"stream\" of particles or molecules leaves whatever source releases it, the source no longer has any effect on it. The water stream bends because gravity pulls it do... | null |
1hs9zm | i'm 27 and i'm starting to notice something. are adults looking and acting younger? or is it my perspective on age that's changing? | [
{
"answer": "That's just ageing. Everyone notices that sooner or later. I'll be 40 this year, and the local university students look like they shouldn't even be able to drive yet. I can remember thinking my parents were old at an time when, in retrospect, they were a fair amount younger than I am now. Then ... | null |
4ja8zo | how can margins of error be trusted? | [
{
"answer": "The margin of error isn't \"We know we're only possibly wrong by this much\" it's \"This is the known accuracy of our instrument under what we believe are operational conditions.\"\n\nYou can still be wrong.",
"provenance": null
},
{
"answer": "Physics has certain ways to calculate unce... | null |
3vgiyq | in the u.s. why are female locker rooms (showers etc.) so private when male locker rooms are almost always wide open practically forcing young boys and men into group showering etc.? | [
{
"answer": "As a guy who found the shower situation in highschool to be extremely awkward, I think men are just raised to be cool with it. I was never cool with it but my class mates had absolutely no problem with it. I was unaware the girls showers were different. We had a square room with shower heads lining... | null |
465wv3 | what will happen with opec planning to halt production? how does it affect oil prices? who is winning and losing? | [
{
"answer": "No one is planning to halt production. Saudi Arabia and Russia have agreed to freeze production at current levels. Considering Russia is already running 100% production and Saudi Arabia is damn near 100% and neither Iraq nor Iran will agree to the freeze it is unlikely to mean much of anything.",
... | null |
62w1df | why aren't our pupils always dilated so that we see more all the time? | [
{
"answer": "Stare into a bright light. How much can you see?\n\nWhen your pupils dilate it is to allow more light into your eyes. Letting in more light in dark situations helps you see better, but letting in more light in a bright situation makes it harder to see and can damage your eyes.",
"provenance": n... | null |
6rq8s0 | how can there be cameras with large resolutions like 42mp and be just a couple thousand dollars, yet a video camera of that resolution be $40-70,000? why does it seem to be so much more difficult to make? | [
{
"answer": " Take your phone into a dim room and take a picture. Now take a video. The picture will be brighter and more detailed even though it's using the exact same sensor. It requires a lot more light sensitivity to take 30 pictures a second than one picture. \n\nIt also takes a lot faster data transfer. (... | null |
681wvm | How wide are rainbows if we consider all wavelengths? | [
{
"answer": "This has been asked before: _URL_0_\n\nThe gist of it is that water absorbs most light below about 200nm and above perhaps 2000nm, so the edges of the rainbow beyond the visible spectrum start to get dimmer. ",
"provenance": null
},
{
"answer": null,
"provenance": [
{
... | null |
au1umt | why dont car batteries need recharging? | [
{
"answer": "The alternator uses engine power to charge it while you’re driving. So it is being recharged, but you don’t need to plug it in. ",
"provenance": null
},
{
"answer": "They actually do have to be recharged, and they get recharged while the car is running by a belt moved by what's called t... | null |
8tpl4i | AskScience AMA Series: I'm Andrew Revkin, the strategic advisor for environmental and science journalism at the National Geographic Society-AMA! | [
{
"answer": "I feel like [this article](_URL_0_) from 2010 was a wake-up call to the poor state of science journalism. Do you think things have gotten better or worse since then?",
"provenance": null
},
{
"answer": "How, from your experience, has the awareness and care about the climate and the envi... | null |
24jiw1 | What kind of sounds does a human fetus hear in the womb? | [
{
"answer": "Babies hear the lower end of the frequency spectrum when they're in the womb. They can get a lot out of that, though. Byers-Heinlein 2010 presents some compelling evidence that newborns of bilingual mothers actually come out of the womb with an ability to distinguish their mother's two languages. T... | null |
3j99br | Concerning the SR-71 Blackbird: What did the USSR know about the plane? What did they think it was capable of? Did they attempt any similar designs of their own? | [
{
"answer": "You might consider asking r/aviation too.",
"provenance": null
},
{
"answer": "Finally something I can help answer! My senior thesis was done on the A-12 program. \n\nSo firstly, I need to mention that the SR-71 was a variant of the A-12 Oxcart program developed by Lockheed for the CIA.... | null |
5qq755 | Why is it impossible for objects weighing less than 0.02 milligrams to form a black hole? | [
{
"answer": "A black hole of mass less than around .02 milligrams or so would have a Schwarzschild radius of around a Planck length or less. At this scale, general relativity cannot be trusted; we need a theory that incorporates general relativity and quantum field theory. Thus, at the very least, we can say ... | null |
2lnwvz | why are humans and most other species dependant on water? is it just coincidence that 70% of earth is covered in it? | [
{
"answer": "If 70% of earth was covered in liquid methane, it's likely we would have evolved to drink methane.",
"provenance": null
},
{
"answer": "We need a liquid that can act as a medium for our bodies to do all the important things it does. \n\nWater is an easily accessible one that is made up ... | null |
4uv4jt | How well does the movie "Master and Commander" portray the life of 19th century British sailors? | [
{
"answer": "Pretty well, actually. The costumes, props, sets, everything was pretty meticulously researched and they do a very good job of avoiding anachronisms or introducing stuff that's just flat out fiction. About the only thing that *really* made me raise my eyebrows was the fact that the *Acheron* was ... | null |
7a4hzm | Musketball vs. Bayonet | [
{
"answer": "You may be interested in [this older answer](_URL_0_) from u/PartyMoses on bayonets and their (non)use in warfare, which posits that bayonets were never much actually used for stabbing, but for intimidation. ",
"provenance": null
},
{
"answer": null,
"provenance": [
{
... | null |
1ukwox | why do middle/high schools start so early when students are going through growth spurts and need the most sleep? | [
{
"answer": "It's mostly for extra-curricular activities. Most sports need reasonable daylight hours, and it would be tough to get faculty to work later through normal dinner / family hours.\n\nIt students need more sleep, they can go to bed earlier.",
"provenance": null
},
{
"answer": "I was once ... | null |
a4nmr5 | how do you order complex numbers? | [
{
"answer": "There's no total order for complex numbers, at least not one that is consistent with the arithmetic operations on the complex numbers. ",
"provenance": null
},
{
"answer": "I suppose if you want order, the magnitude would help not only with purely imaginary numbers following the real nu... | null |
1yuuzq | what is groundhog day and why is it important? (i'm from the uk) | [
{
"answer": "It's February 2nd. If the groundhog sees its shadow (i.e. if it's sunny), then there will be six more weeks of winter, otherwise spring will come early. It is not important whatsoever.",
"provenance": null
},
{
"answer": "Groundhog day is a movie directed by Harold Ramis (who died today... | null |
8ae7be | What is the current state of Japanese historical scholarship in Japan itself? | [
{
"answer": " > how much access do Western (English-speaking, primarily) historians have to Japanese primary sources?\n\nAre you asking how easy is it for foreign historians to gain physical access to Japanese primary sources or are you asking to what extent have Japanese primary sources been translated into f... | null |
2zty7o | In one my my professor's lectures, he mentioned that Japan tried to surrender before Hiroshima, and the US rejected the proposal. After Nagasaki, they accepted a nearly identical proposal to the one they rejected. Is this true? | [
{
"answer": "Like most stuff that gets introduced in lecture courses, it's mostly right, but more complicated.\n\nPrior to the decision to drop the bomb, some members of the Japanese political leadership were working behind the scenes to try to negotiate a conditional surrender whose terms did (in many ways) cl... | null |
1sxrw4 | why did it snow recently in the middle east and why does it happen so rarely? | [
{
"answer": "Deserts aren't big on precipitation of any kind. They also play host to violent temperature extremes. Below zero temperatures in winter nights contrast with sun hot enough to kill. The cold is just as bad for snow as the heat, as you need water in the air to form the snow, before it can fall.",
... | null |
5nz8cg | if someone really did have multiple personalities and each personality had no idea what the others do, what would happen if one of the personalities murdered someone or committed another terrible crime? | [
{
"answer": "Realistically, if we're assuming this is in the United States, this condition would be brought forward and evaluated by a designated mental health official. If it was determined that the crime was committed as a result of these personalities, the individual would likely get to plead insanity and be... | null |
8j7jlm | what is that pressure sensation we feel in our chest when we get a spike of anxiety? | [
{
"answer": "I believe it is adrenaline, the fight or flight reflex. But modern man doesn’t necessarily have the same fight or flight reflex as our ancestors - it’s more fight, flight or freeze. Most people freeze but the body still release the adrenaline used from the original fight or flight.",
"provenanc... | null |
662tph | why are people so polarised? | [
{
"answer": "In my opinion, that polarization has been there. The difference is that now everyone has an anonmomous voice and the more extreme elements are the ones that get all the attention. Not every Christian wants to kill abortion doctors. Not every Liberal is a Sociallist. Most people just want to live th... | null |
anfgg8 | how does removing a storage device from a computer too soon damage the files on the storage device? | [
{
"answer": "The computer could be in the middle of writing to the device and you'd get corrupted stuff. Especially bad if it was updating the file index which tells the computer where everything is on the drive.\n\nGenerally if you've written your files and give it maybe a second or two more it's perfectly saf... | null |
7zf0fz | Is there any evidence to suggest that biracial people are less susceptible to genetic diseases? | [
{
"answer": "There are certain diseases that are more common in populations with more restricted gene pools--Tay-Sachs and Ashkenazi Jews, for example.\n\nHowever, keep in mind that what we think of as \"race\" is not a particularly useful concept in terms of genetics. [There's likely more genetic diversity *wi... | null |
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