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37zcsv
|
why aren't 1 and 0 assigned letters of the alphabet on a telephone?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/37zcsv/eli5_why_arent_1_and_0_assigned_letters_of_the/
|
{
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"crr0jcc"
],
"score": [
12
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"text": [
"Because they have or had special significance for the telephone system. Zero was used to dial the operator, and 1 was the long-distance call code. You couldn't use them at the beginning of a dial sequence as pressing 0 would ring the operator and 1 would cause it to be a long-distance number.\n\n"
]
}
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[] |
[
[]
] |
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21s52r
|
how do i work out the valency of a chemical formula?
|
For example, Mg3Al2(SiO4)3
And I want to work out the valency of manganese in this particular formula.
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/21s52r/eli5_how_do_i_work_out_the_valency_of_a_chemical/
|
{
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"text": [
"Before we get started, that's Magnesium, rather than Manganese, which would be Mn.\n\nOkay, so the first thing to notice is that in this particular formula, there are several sub-parts - the Mg3Al2 part and the SiO4 parts. These are two ions which are stuck together by electrostatic attraction, and they are neutral together, which means that the + parts and the - parts have the same total charge.\n\nThe SiO4^4- aka silicate ion has (obviously) a 4- total charge, which gives you a negative total of -12.\n\nThis means that our Mg3Al2 part must sum up to -12. Now, with this example, it's fairly easy - Aluminium is very commonly in a +3 oxidation state, and Magnesium is almost always +2. If we multiply by each of the numbers of ions contained, we can see that we get 3x2+2x3 which conveniently = +12. Hence, the overall charge is 0. "
]
}
|
[] |
[] |
[
[]
] |
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2blt34
|
why do i need noise cancellation headphones, when i can use any decent headphones and turn on the volume to avoid outside noise?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/2blt34/eli5why_do_i_need_noise_cancellation_headphones/
|
{
"a_id": [
"cj6k8c5"
],
"score": [
6
],
"text": [
"Noise cancellation do what they say, cancel outside noise. So, you don't need to raise your volume so much that it could damage your ears.\n\nLook up: Ear damage from earphones."
]
}
|
[] |
[] |
[
[]
] |
||
5wirra
|
What is the 'corn' Caesar refers to in his Commentaries on the Gallic War?
|
My understanding is that corn, or maize, existed solely on the American continents up until the 15th century and the arrival of European explorers. But Caesar refers constantly to securing a supply of "corn" for his troops. Does the word have another meaning in this context, perhaps just a generic term for food? What food is he referring to? What would his army have been eating as they moved around Gaul throughout the seasons?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/5wirra/what_is_the_corn_caesar_refers_to_in_his/
|
{
"a_id": [
"deadkok"
],
"score": [
23
],
"text": [
"Caesar is likely using the Latin word \"frumento\" or perhaps its plural, \"frumenti,\" to refer to wheat or another grain crop. If you're reading a British translation of Caesar, they're most likely using \"corn\" in the British sense for a staple crop or grain crop, often wheat but not always. Using \"corn\" to refer to maize is a bit of an Americanism; you'll hear maize called \"Indian corn\" in Britain. \n\nThe British Corn Laws (tariffs on imported grain) in the mid-19th century always puzzle American students. "
]
}
|
[] |
[] |
[
[]
] |
|
159wkk
|
What benefits does resting without sleep have?
|
askscience
|
http://www.reddit.com/r/askscience/comments/159wkk/what_benefits_does_resting_without_sleep_have/
|
{
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"c7klf8j"
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"text": [
"Actually, naps are incredibly beneficial. The body has a sleep cycle which goes through 3 stages (previously 4) called Non-REM Sleep + REM sleep (when you're dreaming). The first two stages are really light sleep - in fact if you're woken up from Stage 1 you're likely to think you weren't sleeping at all. \n\nIf you make it into Stage 2 your brain starts to inhibit processing and ignores external stimuli that it deems non-dangerous. It also begins memory consolidation. Waking up out of either of these stages (which generally occur in the first 30 minutes) has been shown to increase **productivity, cognitive function, memory, creativity** and of course **feeling less tired**.\n\nSo chances are you never went into any of the deeper sleep stages, and so you didn't really feel like you *slept*. Regardless, stage 1 and 2 still have benefits for your brain and body! \n\n**TL;DR** Naps (light sleep) are great and actually rejuvenate your mind and body"
]
}
|
[] |
[] |
[
[]
] |
||
53wt7l
|
How was France able to afford an army conquer Europe during the french revolution if it was so poor?
|
I would guess that during the French revolution France was so poor and miserable that the people revolted and started the french revolution.
WHat I don't understand is how were they able to afford to have and supply the Grand Army commanded by Napoleon? A poor empire I would assume wouldn't be able to afford the most powerful Army in the world.
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/53wt7l/how_was_france_able_to_afford_an_army_conquer/
|
{
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"text": [
"Several reasons:\n\n1) France wasn't necessarily poor: the French *government* was because it had problems generating revenue since that required them to increase taxation on the nobility, who had a large degree of immunity from taxes as part of their privileges. The Revolution did away with those privileges, and in the more radical parts simply confiscated their asset wholesale. \n\n2) Occupied territories: one of the reasons why French revolutionary armies were so mobile is that they didn't depend as much on supply trains, which mean that they \"lived off the country\". This translated to looting and stealing from the locals, which meant that France did not have to pay as much for their upkeep. There was also more organized system of forcing \"liberated people\" to pay for French armies: in Belgium for instance this was done through taxation, in Holland through indemnities. In Italy Napoleon managed to extract a \"tribute\" of 60 million Francs during the first 3 month of his 1797 campaign.\n\n3) Rationalization of the internal economy: the revolution did do away with systems of internal tariffs which expanded markets. Traditional guild privileges were abolished, and the new government were somewhat more efficient administrators than the old one.\n\nSource: The French Revolution and the Birth of Modernity by Ferenc Fehér\n\nThe French Revolution By George Rude",
"I'd raise attention to a [splendid post](_URL_0_) by /u/_elos on this subject. "
]
}
|
[] |
[] |
[
[],
[
"http://www.reddit.com/r/askhistorians/comments/2akzlh/_/ciw8z2l"
]
] |
|
1t9eqk
|
How much do we now know about the Kingdom of Zimbabwe? Is this an active area of study?
|
As I grew up in what was then Rhodesia the history we were taught about Great Zimbabwe in particular was heavily censored at the time. Maybe this is why I find the idea of an Iron Age African Kingdom with established trade routes so fascinating, and I'd love to know more than what I've read on Wikipedia.
I understand the topic is pretty broad, so any suggested books for further reading would also be greatly appreciated!
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/1t9eqk/how_much_do_we_now_know_about_the_kingdom_of/
|
{
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"text": [
"Here is a BBC documentary from 2010 on this very subject, part of the 'Lost Kingdoms of Africa' series. \n\n_URL_0_\n\nThe whole series is worth watching in full. \n\nIncidentally Great Zimbabwe was the subject of the very first independent history project I ever did in school! But that's not gonna help us much here as I was about 7 or 8 and as I recall I just copied a few pages out of an old encyclopaedia and drew a bad map of Africa. \n\nBut I find it interesting that you were being censored from learning this stuff whilst growing up in the area whilst I was being encouraged to learn it growing up in the Old Colonial Power (U.K) \n\n",
"Rather than try to tell the story of Great Zimbabwe and its kingdom (or confederacy, or whatever we should consider it), I'll deal with the \"active area of study\" primarily. **Short answer: it's small (miniscule really when compared to archaeology of the same period in, say, Europe) but active.**\n\nInnocent Pikirayi and Thomas Huffman seem to be having the current running exchange about the site of Great Zimbabwe. I didn't know it had extended to the present so vigorously until /u/profrhodes pointed me at the journal *Azania*, where it's happening now. The question is in what the spaces represented, what chronology covers the construction of each part of the (very large) site (see Collett et al 1992 in *African Archaeological Review*), and discussions of material culture took center stage. The most recent of Pikirayi's articles (2013) in *Azania* tries to engage with Shona society and intellectual history more actively, in an effort to link worldviews with structures more integratively than even his own book *The Zimbabwe Culture* (2001).\n\nWhat seems certain is that monumental stone architecture (built in stages in the 12th/13th centuries on) had important roles for maintaining social hierarchies of class and authority, especially in communities built on the accumulation and exchange of wealth in cattle as Great Zimbabwe and its outlying client towns were. It reached its apex at Great Zimbabwe, but being a Zim you probably know that many other smaller stone zimbabwe are scattered around the southern plateau. We don't know the exact nature of the political and social connection between Great Zimbabwe and other zimbabwe, beyond there being one, so that's an open question. I'm not sure everyone yet agrees on which subgroup of Shona-speakers was closer to the builders of Great Zimbabwe, because various Karanga-speakers (and others, like vhaVenda) claim former ownership (or presence) there and there could be truth to any or all of those.\n\nAnother question, which Pikirayi has tried to answer with a decisive \"not really,\" was \"how necessary was coastal trade to these states?\" It was useful, and served to bring in exotic goods that marked status, but the power seems to have remained in the hands of the rulers of the interior--meaning that the southern Swahili coast was more dependent on *them* than vice-versa. When Great Zimbabwe had troubles, Kilwa Kisiwani did too, but based on later episodes the disruption of coastal trade didn't bring down states in the interior (like Mutapa or Butua Torwa). Trade with other people in the interior for various markers of wealth seems to have been more important, but GZ was more heavily involved with the coast than Mapungubwe and the Leopard's Kopje cultures before it, and northerly Mutapa after GZ would be more involved still. So there was an integrative trajectory at work.\n\nIn short we know a lot about the sites and what *material* is there, but not necessarily what it all means in terms of history (society, politics, and the like). That's still a point under discussion and study and it is benefiting from an increasing number of Zim-based academics (Pikirayi, Pwiti, Ndoro, Nyambara on heritage, etc) who can conduct new and more integrative fieldwork than was common in the descriptive archaeological mode of the 1970s or 80s. That work however was thorough enough that it still provides valuable data for newer researchers. The footnotes to the Wikipedia article are a little dated (much like mine, until /u/profrhodes pointed out newer work!) but if you follow them and search Pikirayi on Worldcat you'll find a good amount of material. \n\nThey also, IIRC, just reopened the site not too long ago--they were doing some clearing and reconstruction because tourist dollars (and yes, we do mean dollars literally, but rand in a pinch) like to go there. I'm sure /u/profrhodes, who is still a Zim, can add much more than I have here, and correct anything I've said that is wrong."
]
}
|
[] |
[] |
[
[
"http://www.youtube.com/watch?v=OTVShn1vKV0"
],
[]
] |
|
6qg9rt
|
Members of the German Royal Houses who served in WWII
|
I know that Prince Wilhelm of Prussia served in the Wehrmacht during the invasion of France in 1940 and died during the invasion itself, the reaction by the public following his death was enough to spook the German government into banning members of the Royal Houses (Prince Law?) from serving in the Wehrmacht from 1940 onwards. My question is, prior to the 1940 law, how many members of the former German royal houses served in the Wehrmacht? and then following the 1940 law, how many members served in the Kriegsmarine and/or Luftwaffe?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/6qg9rt/members_of_the_german_royal_houses_who_served_in/
|
{
"a_id": [
"dkx8fbk"
],
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2
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"text": [
"Wasn't \"Wehrmacht\", the general name of the german military under the 3rd Reich? Meaning that if the members of the royal houses were barred from joining the Wehrmacht after the 1940 law, it effectively meant they couldn't join the army (Heer), air force (Luftwaffe) and navy (Kriegsmarine)?"
]
}
|
[] |
[] |
[
[]
] |
|
4un98q
|
Is it possible for a planet to have mountainous terrain that extends past the troposphere?
|
The highest terrain on Earth is Mount Everest, at 8.848km and the troposphere ends at about 12km. Could continuing plate action over millions more years cause Everest and the rest of the Himalayas to extend past the troposphere or even further? Has any planet been observed with such characteristics?
|
askscience
|
https://www.reddit.com/r/askscience/comments/4un98q/is_it_possible_for_a_planet_to_have_mountainous/
|
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"text": [
"From a [related question](_URL_1_) about the tallest possible mountain three years ago by /u/cuddlebadger:\n\n > The tallest possible mountain on Earth is probably around the size of Mount Everest. The reason for this is that higher mountains cause the crust to depress/collapse under them due to sheer mass (the Grenville orogeny in eastern Canada and the northeastern USA is an example of this), and you reach an equilibrium called the isostatic limit (_URL_0_). Of course, this is a long-term equilibrium and can be cheated in the geological short term... like Mount Everest. If you allow for that kind of short-term change, the ultimate height would be dictated by the material's compressive strength, i.e. if mankind went and made a giant pile of rocks for kicks.\n\n > Olympus Mons on Mars is another example of a mountain hitting the isostatic limit. Because local gravity there is lower, the mountain can be much higher.\n\n > There is a whole branch of geology, called paleoaltimetry, that deals with this sort of question.\n\nGravity wants everything to be a sphere. Everest will sink eventually because it is already a bit too tall for the strength of the underlying crust.",
"As an example you have the planet Mars, with it's impressive Olympus Mons at 21 km height over the Mars local datum. ^1\n\n \n\n\nI couldn't find any measurement of Mars' troposphere's height, but the atmosphere's scale height is roughly 60% bigger than Earth's. ^2 Even when scaling up the limit for Earth's troposphere we get a height of 19.2 km. \n(I'm sorry I couldn't find any better sources. If someone has a source that defines the heights of the layers in Mars' atmosphere I'll be happy to update the post. Also, someone better at this - please correct me if I'm missusing the scale height. This is a new area for me.)\n\n\n**[Speculation, because I don't remember the sources]**\nOlympus Mons is a volcano, and from what I remember it was able to gain such an impressive height because of Mars' low gravity compared to Earth which allowed it to not collapse (by forcing the lava to settle lower and lower). And that's why I don't think we could get volcanos here on Earth that surpassed the troposphere's limit. But plate tectonics is very far outside my reach...\n\n\n^1\n Plescia, J. B. (2004). \"Morphometric Properties of Martian Volcanoes\". J. Geophys. Res. 109: E03003. Bibcode:2004JGRE..109.3003P. doi:10.1029/2002JE002031. (Found through: [Wikipedia](_URL_0_))\n\n^2\n_URL_1_\n\n",
"On Earth it's not possible given present conditions (or during the past based on our inferences of what various processes were active and what parts of the Earth system were like). As mentioned in other posts, one important limit is the isostasy and/or the effective elastic thickness of the lithosphere. Basically, as you load the crust (i.e. build a mountain), it deflects the lithosphere down like a sag in an elastic sheet. The amount of deflection depends on the 'effective thickness' of that sheet (I've provided a much more detailed discussion in a response to another comment in this thread). On Earth, another potent process is erosion. In most cases it is difficult for mountains (mostly thinking about entire ranges, but even individual peaks in this case) to extend much above the [equilibrium line altitude](_URL_2_) for glaciers as the glaciers efficiently remove material through erosion. This effect is often termed the 'glacial buzzsaw', which is [reasonably explained in this youtube video](_URL_0_), or you could [read a paper about it](_URL_1_). There are other processes at play as well that tend to keep mountain heights in check, [eclogitization and subsequent delamination of roots](_URL_3_ being one of them."
]
}
|
[] |
[] |
[
[
"http://en.wikipedia.org/wiki/Isostasy",
"https://www.reddit.com/r/askscience/comments/174cxr/how_high_was_the_highest_mountain_ever_on_earth/"
],
[
"https://en.wikipedia.org/wiki/Olympus_Mons#cite_note-Plescia04-5",
"http://nssdc.gsfc.nasa.gov/planetary/factsheet/marsfact.html"
],
[
"https://www.youtube.com/watch?v=lLfM1FB58yA",
"http://gis.ess.washington.edu/grg/publications/pdfs/QR2006_Mitchell.pdf",
"https://en.wikipedia.org/wiki/Ablation_zone",
"https://en.wikipedia.org/wiki/Delamination_(geology)"
]
] |
|
9rpdoj
|
Why do the noble gases change the way our voices sound?
|
askscience
|
https://www.reddit.com/r/askscience/comments/9rpdoj/why_do_the_noble_gases_change_the_way_our_voices/
|
{
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"text": [
"Any gas that is less dense or more dense than the atmosphere will cause sound waves in your mouth to move faster or slower (respectively), making your voice higher or lower pitched (respectively). \n\nNoble gasses are just the safest to do this with because they don't (easily) react with anything else so the only danger is filling your lungs with the gas and then not getting enough oxygen (even though it feels like you are)."
]
}
|
[] |
[] |
[
[]
] |
||
2abi9t
|
why fast food outlets like mcdonalds and subway have to display nutritional information but my local burger/sandwhich place doesn't.
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/2abi9t/eli5_why_fast_food_outlets_like_mcdonalds_and/
|
{
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"The law requiring calorie counts to be posted states that it only applies to restaurants with at least 20 locations. Other laws related to nutrition have their own conditions that apply specifically to chain restaurants. As a result, any restaurant that just operates in a single location is not affected by some of these regulations. ",
"This was a part of the ACA/Obamacare. It only applies to restaurants with 20 locations or more.\n\nThis had to be done in the laws to prevent undue hardship on small family-owned restaurants with just one location.\n\nOtherwise it wouldn't have made it through Congress.",
"I figured it was because of corporate attention. McDonalds is known by pretty much everyone, which means more people can see if they don't display that info and complain. Your local store is only seen by the local customers, so any issues with the lack of nutritional info are handled differently. Probably it'd become a \"if you don't like it, don't eat here\" situation."
]
}
|
[] |
[] |
[
[],
[],
[]
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||
18stgk
|
Idea on Black holes and origin of the Universe.
|
askscience
|
http://www.reddit.com/r/askscience/comments/18stgk/idea_on_black_holes_and_origin_of_the_universe/
|
{
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"text": [
"According to our current knowledge, there's something called dark energy that's actually pushing stronger than the collective gravitational pull that would cause a big crunch. The universe is expanding, and the rate at which it's expanding seems to be increasing, rather than slowing down.\n\nIf dark energy keeps propelling the universe to expansion, we'll end up with a \"big freeze\" instead of a \"big crunch.\" Essentially, everything spreads out, and gets so spread out that it cools down to near absolute zero, and everything is cold and dead and bleak.\n\nThe only way that a big freeze would happen is if dark energy somehow stops working. We can't rule that out as a possibility because we don't really know what it is, but it seems somewhat unlikely.",
"Black holes do [evaporate](_URL_0_). Additionally, while there are some sensationalized reports on other theories, there's no indication a black hole could itself contain a universe. Current, substantiated theories cannot explain the singularity in the black hole and so can make no predication about what's inside it, universe or not."
]
}
|
[] |
[] |
[
[],
[
"http://en.wikipedia.org/wiki/Hawking_radiation"
]
] |
||
1aq2e7
|
why some games absolutely hate being alt+tabbed out (tf2, civ v, skyrim, etc.) while other games don't seem to be bothered by it (wow, diablo 3, dishonored, etc.)
|
Sub-question: Why do you think the windowed fullscreen mode, as in WoW, isn't embraced by other games?
edit: Thanks for the explanations, everyone! Been wondering this forever.
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/1aq2e7/eli5_why_some_games_absolutely_hate_being/
|
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" A lot of games that run while fullscreened essentially \"take up\" the top priority for a job and the rest of the system sits quietly (this is what Source engine games do). Other games that run fullscreened aren't running \"fullscreen\" per se, but windowed and borderless, so it looks full screen but it's still running alongside everything else.\n\nEDIT: Horrendous wording on my part wording. Should have said they're running \"like\" the windowed and borderless modes on Source games. Usually, games like TF2 and CS:S take up a full core or, if you have multi core enabled, two to themselves and your GPU and put your OS and other tasks on the backburner. They'll take up the highest task priority aside from some system programs. When you alt+tab out of them, you have to essentially put the whole game on the backburner and devote your limited RAM to whatever other OS functions are going on and load it all in again. Seriously, go try playing a Source game in borderless windowed mode, and note your CPU usage graphs from the task manager and compare them to Source games in fullscreen. Then compare other games that don't have alt tab issues fullscreen vs windowed borderless CPU usage graphs. The difference is marginal and the option mainly exists in case you have problems with your mouse leaving the window (like is the case with Mount And Blade: Warband's windowed mode)",
"I've been able to Alt-Tab out of the \"Hated games\" you mentioned without any issues. I think it just varies with each person's system. Hell I've been able to run Skyrim windowed with Netflix streaming in Chrome next to it without any issues (no I wasn't watching; it was for my daughter.) ",
"If you can force the games into a maximised window, you should get rid of any 'tab' problems. As others have said, some of the problems with using Alt-Tab may well be system based.",
"[Here's a way](_URL_0_) to get most Source games to run borderless, solving the alt tab problems.",
" > When running in full screen mode, most of the time the game has exclusive rights to the video card and all its resources (most importantly, video memory). As soon as you alt-tab to another application, that's lost so when you come back the game is never sure what assets are still valid and what have been overwritten by other programs. \n > In the olden days of Direct3D this was 'Context Lost' event and the game would have to know everything that was in memory and reload it into DirectX assets (Textures, Models, shaders) which would load them back into video memory.\n[Source](_URL_0_)\n\nGames that handle this context lost event well keep a list of all loaded objects in video memory and restore this when they have focus again. Games that don't handle this haven't properly loaded everything back into memory.\nDX10 apparently solves a lot of these issues for developers.\n\nApologies for not actually explaining it like you're five!",
"Some games, when they are run, capture all of your screen in their frame. This is a good thing because then your computer doesn't have to worry about what's going on in the background and waste graphical power on that, but the flip side is that if you want to switch out of the frame your computer has to do a ton of work to change what it shows you.\n\nAs a note, if you are playing source games, you can set the options to -windowed -noborder to get this effect for a pretty minimal loss of performance",
"You might notice that when a game is running at a different resolution than your desktop your computer will take a minute to switch between the two. To mitigate this problem try matching your in game resolution to your desktop resolution, or vice versa.",
"Just try alt-tabbing out of Everquest pre-2001...",
"Biggest reason loads of people don't realize: Your desktop resolution and in-game resolution differ! Seriously, I had this problem with so many games and using the same resolution in-game and elsewhere fixed it. WoW is especially slow as a mofo if the resolutions don't match.",
"Whatever else you might think about Star Trek Online, they do it right in this regard. They actually give you a minimize button.",
"OP hasn't played FFXI. Without a third party mod, it will always crash if you alt-tab from full screen. They added a windowed mode much much later, but full screen still crashes when you alt-tab.",
"Tabbing out of WoW used to foul up stuff good for me, bugging the game (this was several years ago, early Wrath). I got in the habit of playing in windowed mode, and I still do.",
"Weird, as a rule Civ V has always been pretty kind to me when it gets alt+tabbed. ",
"I've noticed if you continue alt-tabbing you can get skyrim to continue working",
"I worked on a game about 4 years ago for PC and alt-tab was the devil to us. Long-story short: some processes don't handle being \"out of focus\" for very long. Unless you're architecting a system that can survive in a low-memory environment, it's going to get quaky, ESPECIALLY if your packet depot (whose job is to send and receive network packets) goes to sleep when it's out of focus. \n\n",
"I alt tab out of Civ V all the time. but good question for the others. ",
"It's because the company that released the game chose not to make it work; they might have been short on time, money, or talent. It's a question of priorities - sometimes (or more cynically, 'often times') developing a fun gameplay mechanic or designing beautiful graphics is more important to them than releasing a stable game.",
"related question hopefully someone can help with--\n\nI have dual screens and run CS:GO in borderless window mode. my game is on the right monitor, second screen to its left. if I'm flicking my mouse to the left, the pointer will poke out of csgo on to the second screen; if hit any if the buttons on my mouse while the pointer's flickering on the second screen, the game loses focus.\n\nsuuuuper frustrating. can anybody halp me do something that doesn't involve disabling my secondary screen?!",
"Hey, just feel like I should mention this. Skyrim does *not* bug out when you alt+tab. When you click to go back in, just Ctrl+Alt+Del, hit esc, and then click back on Skyrim.",
"Okay, so you know how your main screen is called a \"desktop\"? Let's go with that.\n\nImagine Timmy has a real desk, and he likes to build model planes and model ships on it. Timmy also has to do his homework sometimes. \n\nTimmy is neat and meticulous. When he starts on a new model plane kit, he lays out all the parts, puts little dividers into the box that the kit came in, and sorts all the parts into the dividers. Then, when his mom comes in and tells him to stop playing with his models and do some homework, he just puts all the bits into the appropriate divider sections, closes the box, and carefully sets the model on top of the box. When he comes back to the model, the glue has dried and everything is where he put it.\n\nBilly also likes to make model airplanes. He's not nearly as neat as Timmy, though. When his mom tells him to do his homework, he just throws all the parts back into the box, throws the plane into the box, shoves the box off his desk and starts doing his homework. He feels like this saves him a lot of time, and he's right - Timmy takes almost thirty seconds to clean his desk, while Billy only takes about five seconds. But later, when Billy comes back to his airplane, he finds that the wings bent funny and glued in a weird position, and the landing gear and the decal sheet are glued to the cockpit.\n\nSome Windows games are like Timmy - they go through this whole process of saving their current rendering state, then gracefully deallocating memory so that when you swap back to them, they look fine. This takes a bit of effort and a bit of extra coding, so some games are like Billy and don't bother - and when you swap in and out, they freak out and mangle the display."
]
}
|
[] |
[] |
[
[],
[],
[],
[
"http://forums.steampowered.com/forums/showthread.php?t=1929378"
],
[
"http://hardforum.com/archive/index.php/t-1606740.html"
],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[]
] |
|
4l027d
|
why time theoretically stops at the speed of light
|
Also, do objects travelling at the speed of light simply perceive other things around it as not moving? Or does time literally pass slower for these objects?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/4l027d/eli5why_time_theoretically_stops_at_the_speed_of/
|
{
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"text": [
"I don't know that it's accurate to say \"time stops.\" There is no perspective of time for an object moving at the speed of light. If you do the math we have now, you wind up with an equation that is undefined at c. ",
"The explaination I know has to do with the consistency of the speed of light. If two observers measure the speed of light, both will get the same values, no matter how fast they are moving relative to another. \nImagine a spaceship travelling at near the speed of lieght. Their experiment to measure c would be a laser beam that is pointed at a mirror (in flight direction) and a device that stops the time that the beam needs to get to the mirror and back. \nBecause the spaceship is travelling so fast, it would take more time for the beam to come back to the measurement device. It would measure different values for c when the spaceship is travelling at different speeds. But light is travelling at a constant speed.\nHowever, when the time slows down with the increase of velocity, c is a the same constant in every system.\nWhen travelling at the speed of light, you can not expect any values, because the light can't get back to the point where it came from, making measurements impossible.",
"what you need to understand is that \"time\" and \"space\" are not separate things. They exist in one 4 dimensional space called \"spacetime\"\n\nin spacetime, everything is always moving at \"the speed of light\" through the 4 dimensional space. Usually, this is almost fully expressed in the \"time\" dimension.\n\nAs your speed increases as movement through the 3 \"space\" dimensions, your speed in the \"time\" dimension must decrease, since the vector sum of all 4 dimensions must always be a vector with speed \"c\". In other words: the faster you move through space, the slower you move through time.\n\nIf you move at the speed of light, this means your movement in through spacetime lies fully in the 3 space dimensions. The vector length in the \"time\" dimension is 0. Thus, if you travel at the speed of light through space, time stands still for you.",
"Imagine an old analog clock ticking forward, measuring time.\n\nNow get in a ship and fly away from that clock at the speed of light. \n\nIf you and the light leaving the clock's hand are moving at the same speed, the movement of the clock would appear to freeze.\n\nMove faster than the speed of light and the hands would appear to tick backwards."
]
}
|
[] |
[] |
[
[],
[],
[],
[]
] |
|
3amv19
|
Why doesn't the body break down drugs like caffeine during digestion before they reach the blood stream?
|
askscience
|
http://www.reddit.com/r/askscience/comments/3amv19/why_doesnt_the_body_break_down_drugs_like/
|
{
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"text": [
"Two reasons: \n\n* the absorption rate/location of the drug\n* the metabolism rate/location of the drug.\n\n-\nI'll use caffeine as the example, per your request. Caffeine is absorbed into the blood stream from your mouth, throat, stomach, and intestines. This absorption happens rapidly as you drink a cup of coffee for example, since caffeine is both water- and lipid-soluble. So, it gets into the blood stream pretty quickly and pretty freely. \n\nFurthermore, The enzymes that metabolize many drugs (caffeine included) are expressed in the highest amounts in the liver, not the digestive tract. Caffeine is thus not \"broken down\" until after it reaches the liver through the blood stream. In the liver, caffeine is then metabolized at a much slower rate, leading to a half-life of around 5 hours.\n\n-\nTL;DR: The body doesn't break down caffeine during digestion because it can't.",
"Short answer? Digestion doesn't deal with metabolising drugs. The liver does that.\n\nYour digestive tract isn't there to metabolize your food. it digests it-- beating the complex tissues down into easily aborted and utilized sugars, amino acids, etc. Using acids and reactive lytic enzymes.\n\nNow, when that food gets aborted, the very first place it goes is to the liver, through the hepatic portal vein. Your liver does not digest. It has an utterly REDICULOUS number of enzymes to deal with xenobiotics (chemicals that are not produced in your body, basically.) A well known group of enzymes that do this is the cytochrome family. These enzymes all have the general function of modifying a xenobiotic so that it can be attached to a carrier molecule and excreted (through your pee, often!) A huge amount of drug design is knowING how your liver will metabolise your drug, and very often the drug you take is a prodrug; an inactive form of the drug that, when metabolized by your liver are turned into the active form that has its effect. Drugs like caffeine only last till your liver deals with them.\n\nYour liver also stores sugars and controls a lot of your bodies metabolic and energy processes. Your gut is just the way to break down food into manegable bits, useful or not. It's the Liver that does something with them."
]
}
|
[] |
[] |
[
[],
[]
] |
||
3qqih2
|
if there is a laser razor, then aren't we not that far off from laser hand held weaponry?
|
If human hair has the same strength as copper, and something the size of a safety razor is able to cut through it, then aren't we pretty close to having lazer guns that can damage people?
_URL_0_
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/3qqih2/eli5_if_there_is_a_laser_razor_then_arent_we_not/
|
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"score": [
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"text": [
"Lasers have a number of problems with battlefield application. For instance, there tends to be less dust and debris or other problems like fog and rain between your face and your razor (unless I guess you're a really adventurous shaver). These can provide difficulties for a beam of light that a regular old bullet can ignore with quite a bit more enthusiasm. As well, other things like mirrors present a risk for a laser operating team that a bullet operating team (especially a bullet operating team with mirrors) can scoff at. No mirror is going to reflect perfectly, so a good enough laser could destroy them ultimately, but... well, so does a gun. \n\nYou've not just got to make a laser gun that damages people. You've got to make one that does a better job of it than a gun. ",
"That thing is pretty obviously a hoax. If you watch their videos, you can clearly see the super-heated wire used for actual shaving. Also, the practical explanation they give for the thing makes absolutely no sense.\n\nAlso, all the engineers in their videos have full beards. ",
"There are several problems with that - you'd need a lot of power (big heavy expensive batteries), energy will dissipate as heat and you'd have to get rid of this too and inflicted damage wlil be relatively small - but it's doable.\n\nHowever, as long as you intend to go beside burning enemy's retina, it wlil be really expensive and ineffective. Think of sword heavily decorated with gems. Expensive and not convenient.",
"The U.S. Military DOES have prototypes for laser weapons, but they take up entire rooms and take several minutes to set up and fire something with a trivial amount of firepower. The technology is still too primitive for practical combat usage.",
"There is not a laser razor. That Kickstarter was removed because the group failed to provide a working prototype. ",
"Laser weapons at the moment tend to be good at destroying missiles. Lasers are great at heating up part of the missile and destroying, say, the part in charge of navigation or targeting or even the fuel-tank.",
"Even when we do have combat-ready laser weapons, we will still be a long way off from hand-held laser weapons. There is simply no energy storage method currently that could be miniaturized to that degree and still remain instantly lethal."
]
}
|
[] |
[
"https://www.kickstarter.com/projects/skarp/the-skarp-laser-razor-21st-century-shaving/updates"
] |
[
[],
[],
[],
[],
[],
[],
[]
] |
|
1r7lsp
|
how does a director have any impact on the story itself, since he doesn't write the screenplay?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/1r7lsp/eli5_how_does_a_director_have_any_impact_on_the/
|
{
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"cdkgmyo",
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"score": [
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2
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"text": [
"The writer writes the dialogues, scene setting and some actions. The director directs the actors how the actors are to deliver the dialogues, where they're to stand on the scene, where they're to look and the expressions they're to have, where they're to move in the scene and how they're going to interact with the other characters and the environment around them. As a lot of human conversation is based not just on dialogue but also on body language and emotional cues, its the job of the director to making all these non verbal aspects of human interaction believable, interesting, appropriate for the situation and powerful. \n\nAlso how much the director actually does depends on the director. Some directors only care about the actors and how they're to move, behave and say their dialogues. Then the set director chooses and designs the environment and director of photography (or cinematographer) looks over how the scene is to be framed and focused. Other directors are a lot more involved in the set direction and cinematography too. Stantley Kubrick is a good example of a director with a strong photography background who was also very much involved in not just what the actors are doing but also how each shot was to be framed and focused and how the sets were designed. Many of the big/famous directors are a lot more involved in all the different aspects of the film from set design to photography so they dictate lot more of the overall look of the film than simply it's content. \n\nWhen the direction of the film is bad the actors appear wooden. Like they're simply reading their lines of a script instead of appearing to be having an actual emotional conversation or that the body language and movements of the actor just don't correlate with the dialogue and the actor appear emotionless or just odd. Watch The Room or Birdemic for some really really bad direction. \n\nWhen a film is directed well everything binds together. You feel connected to the characters. Every character appears that they're a real person who exist in the real world and not just an actor reading their lines. There is proper pacing in the story where you don't feel the film is getting bogged down in boring conversations or scenes where nothing happens or things are happening so fast that you don't understand what's happening. And the whole story itself is interesting. ",
"These other two comments do a pretty solid job of explaining the logistics in all of it, so I'm going to leave that be. But I figured I might as well chime in with the best example I can think of, just so you can get a simple and clear idea.\n\nImagine the movie *Jaws*. All of the tension and build up comes from this sense of the 'unknown'. We don't know what's lurking in the water; we don't know if it's a shark or something else, or maybe nothing at all. That's because we never really see it--the camera just bobs in and out of the water, essentially creating the effect that *we're* in the water. Which is scary, because like I said, that would mean we're in the water and we have no way of knowing what's in there with us.\n\nNow, imagine if the director, Steven Spielberg, had filmed it the way it was originally intended. The shark was supposed to be the **STAR**. We were supposed to see the shark all the time, and watch him swim around. (The mechanical shark actually broke in the salt water, which is why they made the decision to not show it quite as much, but that's not the point.)\n\nBasically, what I'm trying to say is that yes, the writer did the writing. But a movie where we watch the shark is a VERY different story than the *Jaws* we know.\n\n**TL;DR-** If we saw the shark in *Jaws* more, the movie would have been tacky and campy."
]
}
|
[] |
[] |
[
[],
[]
] |
||
5j7uzf
|
why do states have different regulations for "open" vs "concealed" carry?
|
Which restrictions are usually more strict - restrictions for open or concealed? Why are the restrictions and regulations different?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/5j7uzf/eli5why_do_states_have_different_regulations_for/
|
{
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"dbe0510"
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"text": [
"Many generations ago, open carry was culturally seen as less threatening (people considered those who carried arms openly as not posing a threat, and those who carried arms secretly as up to nefarious purposes). In that era, laws and regulations were passed that favored open carry of arms. Think of most westerns where almost everyone has a gun in their hip holster, but the bad guy usually has a few concealed weapons. \n\nDuring the 1960s when activists realized that open display of arms could be used as a political weapon, the cultural view flipped, with open carry getting more of a stigma, and concealed carry being favored in the newer regulations. \n\nHowever, the law is very slow, so in many states the law has all sorts of half passed and half rescinded changes that result in a hodge podge of favorable and unfavorable restrictions for both that vary from state to state. \n\nThe general trend in most states for the last decade or two has been to broadly reduce restrictions on carry, with more of a focus on reducing them for concealed carry rather than open carry. "
]
}
|
[] |
[] |
[
[]
] |
|
10kbl7
|
"Melting metal with magnets." What exactly is happening in this gif?
|
_URL_0_
|
askscience
|
http://www.reddit.com/r/askscience/comments/10kbl7/melting_metal_with_magnets_what_exactly_is/
|
{
"a_id": [
"c6e71in"
],
"score": [
3
],
"text": [
"This has been asked many times since that .gif was on the front page."
]
}
|
[] |
[
"http://i.minus.com/ibhivyegZTuldq.gif"
] |
[
[]
] |
|
6hn0w3
|
why, after so many years of living near and around plants, does hay fever still exist
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/6hn0w3/eli5_why_after_so_many_years_of_living_near_and/
|
{
"a_id": [
"dizjclw"
],
"score": [
2
],
"text": [
"Hay fever, particularly mild hay fever, doesn't have a substantial impact on the survival or odds of procreation for over the whole of the human population. \n\nAdditionally, the prevalence and severity of allergies is dependent on many factors, some of which (like more severe allergies developing in people who grow up in clean, largely animal free environments) didn't exist for the overwhelming majority of human history. \n\nNatural selection doesn't care much about inconvenience or even pain, it cares about sex and death. "
]
}
|
[] |
[] |
[
[]
] |
||
xnkpd
|
Let me get this straight: Is space infinite? If yes, then is there infinite matter? If no, does that mean that there is finite matter expanding into infinite space? Does that mean the size of the universe is infinite but the size of the observable is finite?
|
askscience
|
http://www.reddit.com/r/askscience/comments/xnkpd/let_me_get_this_straight_is_space_infinite_if_yes/
|
{
"a_id": [
"c5nxkyw"
],
"score": [
7
],
"text": [
" > Is space infinite?\n\nThe data we have suggests that this is the case, but it's not conclusive. See [here](_URL_1_) and [here](_URL_0_) for more details.\n\n > If yes, then is there infinite matter?\n\nThat is a likely consequence.\n\n > the size of the observable is finite?\n\nThe observable universe is definitely finite in extent and in matter content. The radius of the observable universe is right around 47 billion light-years."
]
}
|
[] |
[] |
[
[
"http://www.reddit.com/r/askscience/comments/xms81/if_all_the_matter_in_the_universe_was_compressed/c5nqva3",
"http://www.reddit.com/r/askscience/comments/xnb4u/how_can_space_be_infinite/c5nx3bg"
]
] |
||
2p74v9
|
why are metal slivers so much more painful than wood slivers?
|
I work in construction and get both frequently but the metal ones are always much more painful. Even a tiny metal sliver hurts more than a larger wood one.
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/2p74v9/eli5_why_are_metal_slivers_so_much_more_painful/
|
{
"a_id": [
"cmty9kd"
],
"score": [
2
],
"text": [
"Moist wood is somewhat flexible. It also isn't really very sharp. Metal is inflexible and can be made to be and stay very sharp."
]
}
|
[] |
[] |
[
[]
] |
|
dfyhxf
|
Why were the various tribes in the Philippines not drastically affected by the Bubonic Plague and Smallpox upon Magellan's (and subsequent Spanish landings) unlike many Indians, and Meso-American societies?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/dfyhxf/why_were_the_various_tribes_in_the_philippines/
|
{
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5
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"text": [
"The answer is pretty straightforward: the Philippines were never isolated from the landmass of continental Asia, unlike the Americas. Therefore, diseases could spread from Asia to the Philippines with relative ease, from contacts with China, India and the Islamic World (as both Chinese and Islamic traders had established regular contacts with the Philippines well before Magellan set foot there). \n\nFor this reason, the advent of the Spanish did not have the devastating impact that they had in the New World, which had been isolated for much longer. \n\nFor pre-Spanish contacts, I would recommend Patanne, *The Philippines in the Sixth to Sixteenth Centuries*. \n\nInterestingly, the earliest known document discovered in the Philippines - the Laguna Copperplate Inscription of around 900 ad - apparently refers to trading relationships with Sumatra. The interconnection of the Philippines and the rest of the world is very ancient. \n\n_URL_0_",
"To get the sorts of deadly \"plagues\" that we see in the Black Death or in the devastation of North American indigenous populations, pathology indicates you need two things. One, you need a source for these pathogens to come from, and two, you need a population large enough to foster these deadly diseases in. While North America indeed had a large enough population to harbor these diseases (as evidenced in the collapse of indigenous cultures when the plagues did eventually arrive), they lacked the source of human borne pathogens that would have exposed them and given them some immunity to the most devastating effects. What is the source of these pathogens? Animals. Usually domesticated ones.\n\nTuberculosis, smallpox, pertussis, measles and many, many more of the earth's greatest hits of diseases all started as animal-borne pathogens passed to humans. Almost certainly this happened because of agriculture and domestication putting a lot of humans and animals in close proximity. As Civilization developed in the old world, so did it's diseases. Especially dangerous were diseases that local populations hadn't been exposed to. Unlike the North America and South America, there were no shortage of domestic animals to serve as disease reservoirs. Almost as if to compensate for the variety, Europe, Africa and Asia had extensive trade and migration which in turn brought rats and fleas carrying each others diseases.\n\nEven with a deadly disease and the presence of a vector, all of that doesn't garuntee a deadly outbreak. Yersina Pestis, the bacteria that causes Plague has existed within human society for millennia, but hasn't always been a constant killer. A complex web of biological, geographical, and cultural factors can play a role in the difference between a handful of people getting sick, and 9/10ths of your population dying. Even in relatively urban environments, it could take centuries for the exact right conditions for a deadly epidemic to come about.\n\nIt might be helpful to consider the timescale of some of new world epidemics. While some outbreaks, like the Cocoliztli epidemics (caused by Salmonella) happened almost immediately with Spanish contact in Mexico, it took centuries for Smallpox to work its way into the Plains tribes, leading the the epidemics of the late 1700s and early 1800s where millions would die from it.\n\nSo, the answer as to why the Philippines didn't suffer immediate outbreaks with Magellan (they would suffer from smallpox in the 1800s) is a combination of getting lucky with their particular arrangement of factors, and partial exposure to disease.\n\nThey key, in my personal opinion, is that they weren't so remote compared to the Americas. They had far more exposure to European, Asian, and African animal vectors. There was at least some immunity within the population, unlike North American people. Long before rats bearing the plague reached the Americas (which happened as late as the 19th century), plague could be found all over eastern Asia, and even today is home to several disease reservoirs. Japan suffered a smallpox outbreak in the 8th century. The Philippines would have been exposed to much of what Magellan could bring long before he arrived via trade with India and other areas. Exposure and immunity don't prevent an outbreak, but it does seem to make one a little less pathologically likely.\n\nWe cannot really prove a negative, and it's often very hard to say why something didn't happen, but at least we can point to a few pathological factors that effect the likelihood, and we can compared and contrast to other cultures."
]
}
|
[] |
[] |
[
[
"http://paulmorrow.ca/lcieng.htm"
],
[]
] |
||
mhodh
|
Is painting on tree trunks okay for tree health?
|
There is a tree at my university that everyone paints on as a sort of billboard/advertising space, and it really bothers me. I'm curious as to what negative effects, if any, this has on the health of the tree. They paint with either housepainting paint/primer, or spraypaint, and it's starting to layer up on the trunk. It seems like it'd be bad for it, but I would like some scientific reasons to argue against painting it. Thanks in advance.
|
askscience
|
http://www.reddit.com/r/askscience/comments/mhodh/is_painting_on_tree_trunks_okay_for_tree_health/
|
{
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"c3107a5",
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"score": [
2,
2
],
"text": [
"The bark on trees isn't especially useful for gas exchange, or photosynthesis since it is dead on the outermost layers. The harm will be minimal, but only so much better than carving your name in it.",
"The bark on trees isn't especially useful for gas exchange, or photosynthesis since it is dead on the outermost layers. The harm will be minimal, but only so much better than carving your name in it."
]
}
|
[] |
[] |
[
[],
[]
] |
|
nwfci
|
Hummingbird inside a car
|
If there's a hummingbird inside your car flying mid-air and the car starts moving, does the hummingbird move with the car or will it go into the rear window? Would it make a difference if the windows are down?
|
askscience
|
http://www.reddit.com/r/askscience/comments/nwfci/hummingbird_inside_a_car/
|
{
"a_id": [
"c3chbvx",
"c3chbvx"
],
"score": [
5,
5
],
"text": [
"As the car accelerates, it will move back relative to the car, but as it reaches a constant velocity it will move with the car.",
"As the car accelerates, it will move back relative to the car, but as it reaches a constant velocity it will move with the car."
]
}
|
[] |
[] |
[
[],
[]
] |
|
8pyf1a
|
batteries have two poles, negative and positive. they can be explained by being a pole with excessive electrons and another one lacking electrons. but what about magnets? we have the north and the south pole? what are them? excess of something, lack of something? what?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/8pyf1a/eli5_batteries_have_two_poles_negative_and/
|
{
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"text": [
"Though the poles of a battery are sort of able to be explained by one having more electrons than the other (this is a better analogy for capacitors than it is for batteries), the poles are actually defined by the behavior of the electric field generated. \n\nCharged particles produce an electric field, which we represent with “field lines.” For an electron, field lines point towards the particle, and away for protons. When you have an object with two poles, one positive and one negative, it’s called a dipole. If you look at the field lines for an electric dipole, they radiate from the positive end and loop around to the negative end. This is very similar (actually looks identical) to the field lines for a magnetic dipole. \n\nMagnetic fields are just like electric fields, save for one important fact: there are (as far as we know) no magnetic charges (monopoles). This means there’s no “north charge” and “south charge.” Magnetic “charges” always come in pairs.\n\nSo to your question, magnetic fields don’t come from a collection of things bunching up like electric fields. Magnetic fields are the result of electric currents (or changing electric fields, but that’s a bit more complex). For example, a wire conducting current will create a magnetic field that wraps around the wire in concentric circles. \n\nI hope this helps!",
"Changes in the “electric field” are due to the intrinsic property of “charge” (positive/negative) whereas changes in the “magnetic field” are due to the intrinsic property of “particle spin” (up/down)\n\nNote: particle spin does not mean that the particles are actually spinning. A more accurate name for this property is “angular momentum” "
]
}
|
[] |
[] |
[
[],
[]
] |
||
636sex
|
why humans come down with minor illnesses all the time but when a pet gets sick it's typically a more serious problem.
|
[deleted]
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/636sex/eli5_why_humans_come_down_with_minor_illnesses/
|
{
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"dfrqs99",
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"dfruvn4",
"dfrv3pf",
"dfs7lpf",
"dfs8e7e"
],
"score": [
73,
6,
12,
7,
8,
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"text": [
"Typically one of the key ways that you tell a human has a minor ailment is they complain about it. Generally it is only serious medical conditions where you can walk into a room and instantly identify that a person is sick by sight alone. (source: EMT, and I walk into a lot of rooms with sick people in, and it nearly always requires questions to identify sometimes ailment). \n\nAnimals can't complain about it if they have the sniffles, or indigestion, or even more serious condition like diverticulitis or rheumatic pain, or sciatica. You might notice a change in personality, you might not, but when they have kidney failure, or a twisted bowel, you will definitely see a significant behavioural change. ",
"I'm not sure the premise of your question is accurate. Pets get 'bugs' and minor ailments just like humans do.",
"It happens all the time, actually. Since I was a kid I've had around a dozen cats. They'll stay in bed even more, move more slowly, throw up and sneeze. ",
"I'd argue this is just response bias. If your pet came down with a 'minor illness,' how would you know? You only realize they're sick when they're really sick. ",
"Its not that they don't. Its more that you don't notice it as much since they can't relay to you that they're sick. You notice when they are really really sick but it is a lot harder to tell when they have the cold for example",
"Unless they are really sick they usually won't show signs besides maybe sleeping more or being a bit lethargic. In general animals try not to show weakness as that is a sure fire way to be preyed upon. ",
"Pets do get minor illnesses all the time. You just never find out about it because animals hide their sicknesses so that predators don't notice them and single them out as weak. And yes, they do actually sneeze, vomit, and other stuff."
]
}
|
[] |
[] |
[
[],
[],
[],
[],
[],
[],
[]
] |
|
2zpywr
|
is it possible to improve your memory to a point where you can memorise a full page of numbers?how?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/2zpywr/eli5is_it_possible_to_improve_your_memory_to_a/
|
{
"a_id": [
"cpl81m6"
],
"score": [
2
],
"text": [
"It's possible to memorize that page using various mnemonic devices such as turning them into a song, or a story, or by breaking them into manageable chunks.\n\nBut it's not like your \"memory is improving\". You're just using a trick to convert the information into a form that your memory can handle."
]
}
|
[] |
[] |
[
[]
] |
||
378dk6
|
Why is the chicxulub crater still intact?
|
Wouldn't the crater be broken up by the continents moving?
|
askscience
|
http://www.reddit.com/r/askscience/comments/378dk6/why_is_the_chicxulub_crater_still_intact/
|
{
"a_id": [
"crl04ug"
],
"score": [
4
],
"text": [
"Hello!\n\n1. Have a solid \"basement rock\" floor.\n2. Build a stable carbonate platform on top.\n3. Smash it with a bolide. \n4. Bury the resulting crater in tonnes of sediment.\n5. Do this over a relatively geologically fast timeframe. \n6. Do this in a passive rather than active margin.\n\nWhile the Chixculub crater is undoubtedly one of if not the best preserved of the largest impact craters we know about, just how \"well\" preserved it is may be a bit misleading if you're just looking at the Yucatan coastline and a schematic of the impact area. \n\nCompare to this, which is perhaps the most current suite of mapping information we have on the crater:\n\n_URL_1_\n\nAnd even as recently as 2008, there was still vigorous debate about what the actual impact structure was comprised of, in terms of features: \n\n_URL_0_\n\nBecause our actual information about the crater features was still that primitive. "
]
}
|
[] |
[] |
[
[
"http://onlinelibrary.wiley.com/doi/10.1029/2007JB005393/full",
"http://onlinelibrary.wiley.com/doi/10.1002/rog.20007/full"
]
] |
|
3lw5oy
|
Interested in Military History
|
This is a question about the use of infantry support weapons in ww2. I have heard many descriptions about how infantry weapons such as the Thompson and BARs were issued in the squad in ww2. For instance, some say the Thompson was issued to the officers, etc. My father fought in the south Pacific in the Philippines. I once asked him this question and he reported that sub-machine guns and automatic weapons were rotated around the squad so that; if one man went down, the other could pick it up and not find it unfamiliar. Every man gained equal experience with each weapon. It was a very team oriented approach. Has anyone else heard of this?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/3lw5oy/interested_in_military_history/
|
{
"a_id": [
"cv9vmkv"
],
"score": [
3
],
"text": [
"The Thompson wasn't usually *issued* to officers per se, but they could scrounge for them. Thompsons were usually issued to drivers and the crews of armored vehicles; officers carried M1 carbines or M1911 pistols. \n\nSubmachine guns evidently found their way into rifle squads at an early time, before the Tables of Organization were updated, but per TO 7-17 and the amendment of June 1944, they were finally \"officially\" issued. Two Thompson submachine guns were issued to the battalion headquarters, and six Thompson submachine guns were issued to the headquarters of each rifle company to be meted out as the commander saw fit; these inevitably found their way to the rifle squads. On paper, the squad leader still carried the M1 rifle. All members of the squad usually carried a few extra magazines for the BAR, giving the gunner potentially several thousand rounds at his disposal. A second BAR sometimes found its way into the Army rifle squad, and on paper, the F-Series Marine rifle squad had *3* BARs.\n\nSources: \n\nTO 7-17 Rifle Company, dated 26 February 1944 (with Change no. 1, 30 June 1944)\n_URL_1_\n\nMarine Rifle Squad\n_URL_0_"
]
}
|
[] |
[] |
[
[
"http://www.ww2gyrene.org/rifle_squad.htm",
"http://www.militaryresearch.org/7-17%2026Feb44.pdf"
]
] |
|
3r59ww
|
why do health inspectors give warnings to restaurants before inspections? wouldn't it make more sense to surprise restaurant owners?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/3r59ww/eli5_why_do_health_inspectors_give_warnings_to/
|
{
"a_id": [
"cwl0076"
],
"score": [
4
],
"text": [
"I don't think they need to warn the restaurants. When they inspect, they typically will give them a certain amount of time in which they need to fix violations before returning. "
]
}
|
[] |
[] |
[
[]
] |
||
4ffl7i
|
why does the same logic not apply to music and other "pirating?"
|
_URL_0_
The Google Books case just got put to rest, why does this reasoning not apply to all copyright infringement cases?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/4ffl7i/eli5_why_does_the_same_logic_not_apply_to_music/
|
{
"a_id": [
"d28fg2c",
"d28g2k9"
],
"score": [
3,
2
],
"text": [
"The key difference is that Google isn't publishing copies of the books that they scan. If they were letting anyone download the full books, that would almost certainly lead to a different court decision.\n\nGoogle is sharing small samples of the books when they're relevant to search results, just like they do with websites and news articles.",
"Fair use. Basically it's OK to use copyrighted works in certain ways that aren't considered a violation of copyright. Google books is undertaking a massive archival process, which is generally viewed as adding value to the original works. Also, Google books only allows you to view small snippets of a book (2-3 pages, i think) at a time. The key point here is if Google books is acting as a \"replacement\" for the original works or is causing them \"irreparable harm\" by somehow driving customers away from paying for the books on the service. \n\nBasically the courts weigh the alleged infringement against the 4 factors test:\n\n the purpose and character of your use.\n the nature of the copyrighted work.\n the amount and substantiality of the portion taken, and.\n the effect of the use upon the potential market.\n\nIf your work is for an approved purpose (review, archiving, searchability, etc) you are good. If you're only using small portions, you're good. If it is unlikely that someone is going to view your \"use\" and then not have a reason to pay for the original, you're good. \n\nIt's important to note that you don't need to hit all 4 points, and can even fail a couple and still have your use considered fair if the other points weight heavily enough in your favor. This is why if you upload a 3 minute scene of a movie to youtube it will get taken down, but if you upload the same scene and provide sufficient commentary on it, you'll be ok (as long as the company that owns it plays by the rules which is an iffy proposition.)\n\nTL;DR Google books is \"fair use\" because it hasn't been shown to adversely affect book sales, and if it has, it's been doing it for good enough reasons."
]
}
|
[] |
[
"http://arstechnica.com/tech-policy/2016/04/fair-use-prevails-as-supreme-court-rejects-google-books-copyright-case/"
] |
[
[],
[]
] |
|
9qfam5
|
how to calculate how many valence electrons there are in a element/atom
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/9qfam5/eli5_how_to_calculate_how_many_valence_electrons/
|
{
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"e88sarx",
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],
"score": [
2,
2,
2
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"text": [
"Valence electrons are defined as the electrons important for chemical bonding, not necessarily the number of electrons in certain orbitals. Periods 4, 5 and 6 have the typical families (alkali, alkaline, etc...) and the transition metals. The typical families have the typical number of valence electrons: alkali=1, alkaline=2, ..., noble=8. The transition metals though have a lot of electrons in orbitals that are easy to break free from the nucleus. Depending on what the metal is interacting with, the number of important electrons can change. The easiest way to think of this is that a given transition metal can have a variable number of valence electrons depending on the type of reaction. (Remember \"valence electrons\" are those that are important to chemical bonding.) So it's not easy to define that number. Transition metals usually have at least 3 valence electrons, no matter the reaction. For some transition metals in some reactions, the number can be as high as 12.",
"If you have a full periodic table you can still count valence electrons left to right in each period (just insert the side groups in between). \n\nIn any case, s- and p-electrons (main group numbers) dominate chemical behaviour which is why side group metals act so similar - they only differ in the number of d- and f-electrons. \n\nBesides that, orbitals only hold 2 electrons each (with opposite spin)- but there are 1 s, 3 p, 5 d and 7 f orbitals per 'shell', with higher order orbitals only available with increasing 'shell-numbers': Shell 1 contains only a s-orbital, shell 2 contains s- and p-orbitals, shell 3 s-,p- and d-orbitals and so on. Due energetic differences d- and f-orbitals only contain electrons one(two) shell(s) later than expected which is why there is a 'two period step' between the main groups and side groups and lanthanides/actinides. All of this can be derived from electron quantum numbers defining the electron state which explains very well the layout of the periodic table - might go a little far though.",
"What you have been told is a simple explanation of what is going on and holds true for the first 20 atoms and for almost all chemical bonds. But a shell can have more then 8 electrons. We have currently identified elements with 32 electrons in a single shell but you can assume no elements have more then 8 atoms in its outer shell. So elements 21 Scandium and 30 Zink have two electrons in its outer shell. However they have different number of electrons in their 3rd shell. The number of electrons in each shell tend to form as a triangle with 2, 8, 18, 32 electrons and then in reverse order back down. However unlike the 20 first elements the rest of the periodic table is full of exceptions to this simple rule so it is harder to teach."
]
}
|
[] |
[] |
[
[],
[],
[]
] |
||
32xa5h
|
Can stars/sky in a photograph give us the location from where the photograph was taken? If so, how does it work?
|
I've seen this happen in movies/TV many times. Also someone was talking about it(confused celestial coordinates with coordinates on earth) in /r/space today. Feel free to go deep about it in your answers if you want.
Edit: A lot of you were confused...Assume that the photographs have timestamps and the angle of the photo with respect to the horizon.
Thanks!!
|
askscience
|
http://www.reddit.com/r/askscience/comments/32xa5h/can_starssky_in_a_photograph_give_us_the_location/
|
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"text": [
"Relevant link below (search star sighting). Currently our submarine launched ICBMs also called SLBMs use a \"star sighting\" system to locate themselves. This is highly accurate and allows them to operate without a communication link to anything. _URL_0_",
"What kind of photograph are we talking here? Just a photograph of a small patch of sky? In that case, it would be really hard. If, on the other hand, it was a photo of stars in the sky with a time stamp and we knew the direction (as in, how the stars are compared to the horizon) then yes, you could figure it out if you wanted but it would be really difficult. Far easier to just work it out from the GPS signals you can get anywhere on Earth.\n\nFun random little fact: it's not from a photograph, but stellar timing is a thing because of pulsars, which are accurate to the nanosecond level and are often used in what are called [pulsar timing arrays](_URL_0_). You can use pulsar information to know where you are within 5km of a location- not bad at all, I think!- but the nice thing is this also works *in outer space*, not just on Earth. So maybe it's the radio astronomy bias showing here, but this is the stellar navigation I would work backwards from myself. :)",
"It's called celestial navigation and has been used for a thousand years or more.\n\nIt's very good at telling you your lattidue (how far north/south you are). For example, if you can see the Northern Star you know you're in the northern hemisphere. If that star appears directly above you you're really close to the North pole. If it appears nearly on the horizon, you're really close to the equator. \n\nKnowing the exact angle to the North star can give you extremely accurate latitude.\n\nLikewise, knowing the angle of the sun at precisely noon (it's zenith) can give you latitude as well. If you know exactly when the sun reaches its highest point in the sky for a day, you can determine how far east/west you are (because you can determine which longitude you're on).\n\nSo yes, celestial navigation is an art that's been nearly lost thanks to GPS. It's still used by satellites and other things in space (like ICBMs, SLBMs, and a variety of space probes). ",
"Generally speaking, it's not possible to do that from just a photograph of the sky, though I might be misunderstanding the question. (Maybe link the /r/space discussion?) The issue here is that astronomical objects are really far away, so everyone on Earth is essentially seeing them from the same angle relative to each other -- therefore, the relative positions of stars on the sky don't tell you about your location on Earth in a useful way.*\n\nHowever, this changes if you have two additional pieces of information: the exact time the photo was taken, and/or the position of the photo in the sky when it was taken (i.e., the angle of the photo with respect to the horizon and cardinal points). You can calculate the position from these additional pieces of information because...\n\n1) the positions of stars generally don't move relative to each other (at least not very quickly as seen from Earth), so we can effectively create a fixed map of all the stars in the night sky (from straight above the north pole, to straight over the equator, to straight over the south pole) that just rotates around us in a simple way as the Earth revolves;\n\n2) any photo of the sky that includes 3 or more stars can almost certainly be uniquely identified to a position on this map based on the relative positions and brightnesses of the stars (by matching with a catalog of stars that can be seen from Earth);\n\n2) the part of this map you can see at a given angle from your reference horizon only depends on where you are on Earth and what time it is (ok, I'm assuming no clouds or ceilings).\n\nThis is basically how ancient mariners, etc., figured out where they were using the stars... they needed 1) to know where on the \"star map\" they were looking (hence maps of constellations), 2) where the star they were seeing was above the horizon (hence sextants), and 3) what time it was (hence the importance of clocks that stay accurate on a moving ship).\n\n_URL_1_\n_URL_2_\n\n(* Big caveat here: if you move a *really* big distance, you *can* actually see stars move relative to each other (in that the positions of nearby stars move with respect to more distant stars). This is called stellar parallax, and it's actually the most fundamental way we calculate distances to nearby stars, using the fact that the Earth moves a very large distance (2 AU) in its orbit every 6 months. *)\n\n_URL_0_"
]
}
|
[] |
[] |
[
[
"http://en.m.wikipedia.org/wiki/Trident_%28missile%29"
],
[
"http://nanograv.org/science/pta.html"
],
[],
[
"http://en.wikipedia.org/wiki/Stellar_parallax",
"http://en.wikipedia.org/wiki/Marine_chronometer",
"http://en.wikipedia.org/wiki/Sextant"
]
] |
|
2lrc4n
|
what causes comment threads in eli5 to be deleted or locked?
|
I have been looking through old posts and I keep seeing deleted comments with replies or whole comment threads deleted or locked posts. I've read the rules but it seems random in the actual threads
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/2lrc4n/eli5_what_causes_comment_threads_in_eli5_to_be/
|
{
"a_id": [
"clxeu1q"
],
"score": [
2
],
"text": [
"We delete comments that violate the rules. So rude comments directed at other redditors, or top level comments that are irrelevant to the question (jokes, etc), and that sort of thing. Threads get locked mostly because they have been adequately answered already but are attracting large numbers of comments that break those rules, and moderating them is more trouble than it is actually worth. "
]
}
|
[] |
[] |
[
[]
] |
|
1086ob
|
Have there ever been any groups of people whose soldiers would hold their funerals BEFORE going into battle/dying?
|
I know I've read of this before, but I can't recall whether or not it was history or something I'd read in fiction.
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/1086ob/have_there_ever_been_any_groups_of_people_whose/
|
{
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"text": [
" > read in fiction.\n\nPerhaps your thinking of the Legion of the Dead in Dragon Age Origins? ",
"Didn't the Kamikase hold ceremonies prior to them taking off? I'm not sure if you'd call it a funeral, but they were very much openly acknowledging they would not be returning. ",
"Allegedly in the Romance of the Three Kingdoms (keep in mind this is semi-historical work based on a biased and embellished version of real historical events) Pang De, before joining the relief expedition of Fan City, held a feast in which he paraded his own coffin to demonstrate his dedication to emerging victorious and to reaffirm with his subordinates his loyalty and willingness to die for Cao Cao."
]
}
|
[] |
[] |
[
[],
[],
[]
] |
|
18y8mc
|
is it really possible to hear the difference between an uncompressed .wav and 320kbit .mp3?
|
I cant really figure out, what all that is about.
where exactly are the big "problems" of mp3 encoding, even if using a high bitrate?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/18y8mc/eli5_is_it_really_possible_to_hear_the_difference/
|
{
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"text": [
"Many people think or like to think that they can, but they will fail in blind tests. The same kind of people who will praise cheap wine if they're seeing it poured from an expensive wine's bottle.\n\nA computer can tell the difference of course because it can mathematically discern the difference. MP3 also cuts off extra high frequencies. Ones that we can't hear anyway, mind you.",
"Well *some* people claim they can tell the difference. Though I'm not so sure I believe them.\n\nIsn't the important question whether *you* can tell the difference? If so, [give it a try](_URL_0_) using the blind test.",
"Compression is achieved by crushing parts of a file that humans don't normally hear so well. Most people don't hear above 16kHz and that goes down with age. You can safely compress everything from about 12kHz and up, as well as roll off everything above about 20kHz (considered the threshold of human hearing). Same thing is done on the low end. \n\nConsidering most music is heard on cheap earbuds through devices that are not capable of accurately reproducing extreme high or low frequencies, there's no point in having them (although audio enthusiasts will argue differently). \n\nYou specifically asked about 320kbps mp3s, which are pretty dang close to wavs. Almost pointless to keep that level of mp3 instead of a wav if you have the storage. Remember that media players aren't just playing back music, they're decoding the compression as they go. When you have a large file decoding, you might notice your player having trouble uncompressing as it plays (might might might might.... might). \n\nOn the subject of wav files, they're ideal for music and film production because they store frequency ranges (with the right data rate) that are far outside of human hearing. That's not particularly useful for the end listener, but considering how much processing occurs during the production process, you lose a lot of data along the way. If you start with the bare minimum, you won't have any room to lose. \n\n**TL;DR**: It depends on your hearing levels and the quality of gear you reproduce it on. Probably not, but it is a measurable difference. ",
"I don't really know anything about what makes the encoding different that someone hasn't already said here, but I can occasionally tell the difference in some songs depending on how they're mixed.\n\nBeing a drummer, I tend to listen primarily to drums and in some cymbal-heavy songs, higher-pitched cymbals in lower-bitrate encoded songs tend to sound a little bit buzzy, for lack of a better term.\n\nLike /u/freakame mentioned below, it's because the compression is built to crunch parts of the audio that humans don't hear well, such as extreme highs and lows. Since cymbals (especially higher ones like crashes) are catching a lot of that range, I can sometimes catch that it doesn't sound quite natural.",
"Yes. Not to sound like a snooty audiophile, but with some tracks, I can definitely hear a difference. I'm 34, with some midrange hearing loss (though my high frequency hearing is still intact). \n\nThe track can't be anything that's been hit with too much dynamic range compression in the studio. Most of the differences I hear between a WAV and an MP3 is a slight loss in dynamic range. Transients lose a little of their impact. The WAV just sounds... bigger. \n\nThat said, I don't keep all my audio in FLAC or WAV, but in ~225kbps MP3s. Is there a difference? Yes, but I only ever hear it with A/B comparisons. It really is good enough, even with good headphones. \n"
]
}
|
[] |
[] |
[
[],
[
"http://nigelcoldwell.co.uk/audio/"
],
[],
[],
[]
] |
|
kkd8g
|
What would the lifespan of someone born in the past two decades be?
|
I'm curious. I'm 21 and wondering what my generation's average lifespan is relative to, say, my parents'. Anyone have any idea?
|
askscience
|
http://www.reddit.com/r/askscience/comments/kkd8g/what_would_the_lifespan_of_someone_born_in_the/
|
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"text": [
"our increasing lifespans are largely due to medical advances, new drugs and treatments..\n\nSo unless somebody wants to go out on such a limb as to predict the next 50 years of medical advances, the question can't be answered reliably..",
"Here are the [actuarial tables](_URL_0_) the US Social Secuirty administration uses.\n\nA 21 year old male can expect to live to be 76, a female 81.",
"our increasing lifespans are largely due to medical advances, new drugs and treatments..\n\nSo unless somebody wants to go out on such a limb as to predict the next 50 years of medical advances, the question can't be answered reliably..",
"Here are the [actuarial tables](_URL_0_) the US Social Secuirty administration uses.\n\nA 21 year old male can expect to live to be 76, a female 81."
]
}
|
[] |
[] |
[
[],
[
"http://www.ssa.gov/oact/STATS/table4c6.html"
],
[],
[
"http://www.ssa.gov/oact/STATS/table4c6.html"
]
] |
|
20ictq
|
how is veto power fair?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/20ictq/eli5_how_is_veto_power_fair/
|
{
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"text": [
"If you mean in the US government, it ensures (in theory) that no one branch of the government is all-powerful. It's part of the system of checks and balances.",
"It's one of the powers of being a chief executive, either of a state or the nation as a whole. It's a privilege of being the boss!\n\nBut - as with most things - there are checks to this power. In the US, vetoes are never airtight - there's always an ability to prevent a veto. In most cases, this means a certain percentage of votes (ex. 75%.) So if a legislature voted and passed a bill overwhelmingly, and then sent it to the President's desk, he or she couldn't veto it if the bill passed with a certain margin. So the President or governor would know that he or she would need to sign the bill in that case...but it's very unlikely that any executive leader would be forced to sign something he or she didn't want to. \n\nTL;DR it's one of the powers of being an executive leader, but can be circumvented. The veto power is not absolute. ",
"The Veto in the UN is a very powerful tool. Unfortunately, it results in resolutions being stuck in transition if it affects one of the 5 countries with veto rights. In light of Russia using their veto against the resolution of Crimea, one can tell that it isn't fair. Russia and any of the P5 are pretty much immune to international law, which is not helping matters in Crimea, in Syria and will not help things in the future."
]
}
|
[] |
[] |
[
[],
[],
[]
] |
||
t3vqd
|
Where can I get a tl;dr/simple rundown of Greek mythology, specifically the gods and titans
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/t3vqd/where_can_i_get_a_tldrsimple_rundown_of_greek/
|
{
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"c4jbpfp",
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],
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6,
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"text": [
"This is exactly what [Wikipedia](_URL_0_) is good for. It hyperlinks to articles on more specific topics (such as more detailed breakdowns of the Olympians).",
"The book you want is [Bullfinch's Mythology](_URL_0_)",
"[op might want to try this](_URL_0_), or, for a bit more thorough/historically minded view - which I personally recommend - [this](_URL_1_)."
]
}
|
[] |
[] |
[
[
"http://en.wikipedia.org/wiki/Greek_mythology"
],
[
"http://www.amazon.com/Bulfinchs-Mythology-Modern-Library-Classics/dp/0375751475"
],
[
"http://www.amazon.com/Oh-My-Gods-Modern-Retelling/dp/1451609973",
"http://www.amazon.com/Myths-Ancient-Greeks-Richard-Martin/dp/0451206851"
]
] |
||
556eb3
|
Is Sanskrit the oldest written language? If not; what is?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/556eb3/is_sanskrit_the_oldest_written_language_if_not/
|
{
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"d887pse",
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"score": [
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3
],
"text": [
"No, not by far. The oldest writing systems used for Sanskrit, Brahmi and Kharoshti Script, developed in the 3rd century BC. By that time, there were a number of other writing systems around already (both scripts are actually theorized to be derived from the Phoenician Alphabet, which is as well the origin of the Latin alphabet). What is generally assumed to be the first writing system is Sumerian cuneiform, for which the earliest sources date back until ca. 3300 BC. ",
"As DucklingsOfDoom points out, Sanskrit does not approach the status of our oldest language of which we have attestation of a written tradition. But moreover, I phrase that characterisation precisely as I do because it is even further from being the language of which we have the oldest extant texts. \n \nSanskrit's claim to fame is really the antiquity *within the Indo-European sphere* of the *composition* of the *oral* tradition of Vedic literature. Outside the Indo-European sphere or in a manuscript context, the antiquity of Vedic literature is not especially remarkable. In the Indo-European sphere, Hittite and Mycenaean Greek, for example, immensely predate it. And outside the European sphere, Egyptian, Sumerian, and the various cuneiform scripts (for unrelated languages) which proceeded from the latter, and alphabetic scripts (mostly Afroasiatic) which proceeded from the prior, do so even more extremely."
]
}
|
[] |
[] |
[
[],
[]
] |
||
1ksn79
|
Did fear of Communism play a significant role in the granting of civil rights to American blacks?
|
I've read that the Soviets saw the black underclass in the USA as potential allies, and I know that groups like the Black Panthers embraced a kind of revolutionary Marxism. But is there any evidence that the political will to end segregation and Jim Crow was stimulated by fear of an African-American "fifth column" in the USA?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/1ksn79/did_fear_of_communism_play_a_significant_role_in/
|
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"text": [
"From what I have read, In Manfred Berg's Ticket to Freedom. It appears that the fear of communism, took more of a center stage in american politics, and put civil rights on hold. There is a theory of the \" Long Civil Rights movment\" which describes the movement as something much longer than the popular 50-60's movement. According to the long civil rights idea, The civil rights movement started in the 30's with the help of American Communists and socialists as they found the blacks to be the most oppressed people in the United States. Druring the Red Scare, which it seams is the period you would like to know about, many civil rights groups like the NAACP tried to destance themselves from the communists. They were afraid of being associated with the communists because, many still believed that civil rights was a communist plot. More moderate groups like the NAACP didn't like many of the early soviet communists becasue some suggested taht it would be better to isolate and create a seperate black nation, rather than integrate. This question really can be answered hundreds of different ways, and with many different perspectives, but from what I understand, The red scare era, really put civil rights in the back of the line of the political adjeda. I'm sure though, somebody will come shortly to give you a well thought out answer.",
"You could also look at the question of Communism on an international level.\n\nMy university lecturer did a module last year on the Civil Rights movement, and argued that one reason for 'appeasing' the CRM was to ensure continued influence globally.\n\nThink about it - post-WWII, developing countries were being granted independence, and obviously the majority of the population in these countries was black. While America and the USSR competed for influence in the country, America was being hindered in doing so by the seemingly contradictory nature of disadvantaging the black population in its own borders (or so my lecturer argued).\n\nThus, the American government's granting of Civil Rights was arguably a tool for countering Communism in the developing world.",
"An interesting article from NPR on the topic.\n\n_URL_0_\n",
"Wow, it's almost like I planted this question myself, it's so right up my alley! I hope I can help!\n\nFirst, let's talk African American communists. In 1928, the Sixth Congress of the Communist International in Moscow passed “The Resolution to the Negro Problem.” The resolution held that African Americans in the South constituted as an oppressed group and they had the right national self-determination. Furthermore, the resolution ordered the Communist Party of the United States to “come out openly and unreservedly for the right of Negroes to national self-determination in the southern states, where the Negroes form a majority of the population.” (Harvey Klehr, *The Heyday of American Communism: The Depression Decade*) By recognizing these rights to national self-determination and the Party's responsibility to African Americans, the leaders Communist Party of the United States placed the “Negro Questions” at the center of their work. The CP focused a good amount of attention on organizing African Americans, especially in the south. (see Robin D.G. Kelley, *Hammer and Hoe: Alabama Communists During the Great Depression*) In addition, local Communist Parties addressed issues facing African Americans on local grass-roots levels, like aiding in strikes where the majority of workers are African Americans. While African Americans never joined the CP in huge numbers, the working class was generally receptive to their message (prior to World War II) (for more, see Mark Solomon, *The Cry Was Unity: Communists and African Americans, 1917-1936*). \n\nHowever, the efforts of African American communists, as well as their non-black comrades, were stymied at every step (many times, by their own organization). Like /u/ahump pointed out, more moderate African American organizations disagree with the Communist Party's efforts and often sought to distance themselves from their radical activity. In worst cases, the NAACP and moderate African Americans would sell out the Communists at the expense of civil rights. In *Eyes off the Prize: The United Nations and the African American Struggle for Human Rights, 1944-1955*, Carol Anderson argues that initially, African Americans approached the international scene after WWII asking for human rights. When that term became contested and associated with communism, moderate groups, like NAACP, withdrew that component and instead demanded civil rights. That is, instead of focusing on human rights, like the Communists (purportedly) did, the NAACP narrowed their focus to civil rights, i.e. legal rights in the United States because it was easier politically to sustain. The LAST thing the NAACP wanted was any association with the Communists. For their part, the Communists accused the NAACP of being race-traitors, Uncle Toms, and worse.\n\nIn terms of how African American communists fared under a Cold War American government, they carried the double burden of racism and anti-communism. However, they were not more feared than any other communist, and certainly their radical alliance was no reason to enact civil rights legislation. **So in a seriously truncated answer to your question, NO. The US wasn't frightened by African Americans' relationship with the communists enough to pursue civil rights.** Civil rights were achieved because of international and domestic, legislative as well as social, moderate and conservative, reasons. \n\nIn short, the answer is complicated (but what isn't in history?!), but the civil rights agenda took priority over more radical revolutionary ideas espoused by the Communists. Indeed, the threat of communism actually helped African Americans in the international sense. When African Americans went abroad or published internationally, they related their experiences of a Jim Crow America. The United States claimed itself a bastion of freedom and equality in contrast to the Soviet Union. When images of dogs lunging at black protesters in Birmingham went worldwide, it was first embarrassing to the United States, and second dangerous because it could turn international sentiment toward the Soviets (Penny von Eschen, *Race against Empire: Black Americans and Anticolonialism, 1937-1957*). In fact, the federal government so feared their treatment of African Americans could endanger international relations, they sent popular jazz musicians Dizzy Gillespie, Louis Armstrong, and others around the world in a good-will tour that really served to show how well African Americans were treated (Penny von Eschen, *Satchmo Blows Up the World: Jazz Ambassadors Play the Cold War*). \n\n\n\nI also wanted to point out that you're right that the Black Panthers espoused a revolutionary Marxism, but that was post-Jim Crow era (though the Panthers argued that the Civil Rights movement did very little). And their type of Marxism was not the same Marxism feared in the Red Scare. The Huey Newton (the theoretician behind the Black Panthers) founded the Party's revolutionary theory around Mao-ism, Franz Fanon, and the anti-capitalist sentiments of late Malcolm X. While the Black Panthers were sympathetic to the Soviet Union, their general politics focused on domestic issues in the United States."
]
}
|
[] |
[] |
[
[],
[],
[
"http://www.npr.org/templates/story/story.php?storyId=123771194"
],
[]
] |
|
3r6ov9
|
why is it that when a bottle of coke is shaken the bottle might explode because of the gas built up ? it's not like the co2 isn't there before it was shaken.
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/3r6ov9/eli5_why_is_it_that_when_a_bottle_of_coke_is/
|
{
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"cwle81p"
],
"score": [
6
],
"text": [
"Actually, that's exactly what it's like. The CO2 is bound up in carbonic acid inside the drink itself, and isn't in gaseous form. Shaking it actually produces CO2. So you're right - the gas actually _isn't_ there before it's shaken. "
]
}
|
[] |
[] |
[
[]
] |
||
202dya
|
Did Nazi Germany or the Nazi Party ever acknowledge the fact that Hitler wasn't blonde haired and blue eyed?
|
It strikes me as something that would have been a huge elephant in the room. The Nazis advocated for the position that blonde, blue eyed individuals were the most racially pure, and the man leading the party had black hair and brown eyes. Was this ever addressed, at any time, or did everyone pretend like they didn't notice?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/202dya/did_nazi_germany_or_the_nazi_party_ever/
|
{
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],
"score": [
7,
10,
3
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"text": [
"He had blue eyes: _URL_0_",
"The idea that blonde hair and blue eyes were the epitome of Aryan purity is actually a major oversimplification of Nazi propaganda.\n\nIt's true that the blonde haired blue eyed type was often featured in propaganda posters (although even then, not exclusively), but it was not promoted as literally the most perfect physical type.",
"To add to what /u/daedalus_x has said, blue eyes and blonde hair was an ideal, but German propaganda actually tended to downplay physical features when discussing the ideal Aryan. A Hitler Youth booklet called \"Faith and Action\" says: \"Race means to be able to think in a certain way. He who has courage, loyalty and honor, the mark of the German, has the race that should rule in Germany, even if he does not have the physical characteristics of the “Nordic” race. The unity of the noble soul and a noble body is the goal to which we strive. But we despise those whose noble body carries an ignoble soul.\"\n\nHitler's actual definition of 'Aryan' changed based on what was politically convenient. Originally it was \"white, non-Jewish\" but it became necessary for him to add Slavs to those who were white but not Aryan. The lack of a specific definition allowed him to change it when it was convenient, as was the case in Yugoslavia with the Serbs being considered the \"most Aryan\" in the region... until a Serbian anti-Nazi coup forced him to declare the Croats the most Aryan."
]
}
|
[] |
[] |
[
[
"http://rarehistoricalphotos.com/rare-color-photo-adolf-hitler-shows-true-eye-color-date-unknown/"
],
[],
[]
] |
|
2wzmux
|
investment bankers on wall street are known for working insanely hard (100+ hour weeks). what exactly are they doing that requires them to work so long?
|
I basically understand what investment bankers do, but I don't get where 100+ hours per week of work comes from.
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/2wzmux/eli5_investment_bankers_on_wall_street_are_known/
|
{
"a_id": [
"covjm08",
"covjwpb"
],
"score": [
3,
3
],
"text": [
"Trading is a very time-critical activity. Global markets never shut down completely. Every second that you are not on the job can mean a missed opportunity. Good opportunities are rare and it's hard to predict when they arise. That leads some traders to chase big wins, almost like gambling addicts.\n\nAlso, some Wall-Street companies have highly competitive, cut-throat work cultures, where the poorest performers get culled regularly.",
"The job has a ton of reading, writing, and talking at the most basic level. The lowest level jobs are usually analysts who are paid to be experts on all the major companies in an industry. They usually read several hundred pages of [corporate reports](_URL_0_), read all the external news about the industry, write 5-10 page summaries, and talk to clients about their conclusions for a few hours a day.\n\nAbove them are junior bankers who read hundreds of pages of reports, legal filings, and create strategies and options for clients (who've shifted from large investors to corporate management). They'll prepare pesentations outlining strategies for mergers, selling stock for the first time, and bond placements. "
]
}
|
[] |
[] |
[
[],
[
"http://www.sec.gov/Archives/edgar/data/320193/000119312514383437/d783162d10k.htm"
]
] |
|
5sy1gc
|
How is it possible that 100,000,000 people died in the Taiping Rebellion?
|
The Wikipedia page on the Taiping Rebellion lists the death toll at one hundred million people, but doesn't give an answer as to how this is possible. How did it happen? And have there been more deaths ever before?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/5sy1gc/how_is_it_possible_that_100000000_people_died_in/
|
{
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"dditeyh",
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2
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"text": [
"Just want to point out, the [wikipedia article](_URL_0_) says:\n\n > **Total dead**: 20-30 million dead (best estimate)^[7]\n > Highest estimate: 100,000,000\n\nThe source cited for [7] is Stephen R. Platt. *Autumn in the Heavenly Kingdom: China, the West, and the Epic Story of the Taiping Civil War*. (New York: Knopf, 2012)\n\nI don't have an answer, just doing this for clarification purposes",
"I know I'm a little late here, but in the episode of [In Our Time](_URL_0_) on the subject, Prof. Mitter says that the higher estimates of 70-100 million are generally given by the Chinese government, and they include the next generation of children that were never born in the list of \"casualties\".\n\n20 million seems to be the accepted estimation."
]
}
|
[] |
[] |
[
[
"https://en.wikipedia.org/wiki/Taiping_Rebellion"
],
[
"http://www.bbc.co.uk/programmes/b00yqvqt"
]
] |
|
25xdux
|
Why do certain sounds sound appealing and others don't?
|
askscience
|
http://www.reddit.com/r/askscience/comments/25xdux/why_do_certain_sounds_sound_appealing_and_others/
|
{
"a_id": [
"chlv477"
],
"score": [
12
],
"text": [
"Three incomplete explanations:\n\n1. A sound can be appealing because it is associated with a pleasant experience. If you grew up near the ocean, for example, a distant foghorn might be a pleasant sound.\n\n2. As for the quality of sound, it might be that we are born appreciating certain sounds that are associated with well-being or survival, such as kind human voices or trickling water. Both could indicate safety and security.\n\n3. In music, we tend to appreciate certain harmonies. These tend to feature a moderate amount of dissonance. Two tones played in unison (both the same tone) sounds nice but is uninteresting, as the frequencies (as measured in Hertz) have a simple 1:1 ratio. An octave has a 1:2 ratio and sound a little more colorful. Other harmonies have more complex ratios like 2:3, 3:5, etc. These are more colorful still. As the ratios get more complex they start to sound sad, and then eventually hideous. The most complex ratio within an octave on a piano keyboard is 45:32, known as a tritone. It sounds very \"ugly\". To hear a tritone, play the notes C and F# simultaneously."
]
}
|
[] |
[] |
[
[]
] |
||
2q0oo6
|
why does curling up into the fetal position help stomach/period cramps?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/2q0oo6/eli5_why_does_curling_up_into_the_fetal_position/
|
{
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"text": [
"I believe it minimize the use of those muscles and allows them to relax, therefore hurt less. ",
"Not sure why it is that way for some people. \nI've actually found that laying on my side isn't the best sleeping position when I'm having menstrual pains. I prefer to lay on my back with a pillow under my knees, and a heating pad on my stomach.\n\nI found that tip in a Women's Health mag article about sleeping positions for different ailments, and it's worked for me so far!\n\n_URL_0_\n\n",
"It relaxes all the abdominal muscles and makes it so the stomach isn't stretched out as much. "
]
}
|
[] |
[] |
[
[],
[
"http://www.womenshealthmag.com/health/sleep-positions"
],
[]
] |
||
1snfft
|
chemistry bonds
|
Explain the differences between a covalent bond and an ionic bond. Please, I really don't understand it.
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/1snfft/eli5_chemistry_bonds/
|
{
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2
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"text": [
"In a covalent bond, the electrons are being shared by the the atoms. In an ionic bond, one atom had completely taken done electrons from the other. In this case, bbot atoms become oppisitely ccharged, and the electrical aattraction between their charges keeps them together.",
"Now how does polarity play a role in the bonds?",
"Thank you so much"
]
}
|
[] |
[] |
[
[],
[],
[]
] |
|
y33j4
|
Physics - Nuclear Fusion
|
I was trying my best to explain nuclear fusion to somebody today and I came to one important question: If you perform nuclear fusion with, let's say, Deuterium and Tritium, having Helium 4 and a Neutron as a result, with incredible amounts of energy of course, where do the matter destroyed by the fusion go?
Wikipedia says that the Neutron is "freed" in the reaction, but in my opinion you actually reduced some matter to an energy status. Can matter and energy be the same thing, something we would call "being" generally speaking? I understand that the sun takes hydrogen and makes helium and so on. Could we say then that the end of the universe will come when all matter have been fusionned in very heavy atoms, freeing energy but emptying the world at the same time?
|
askscience
|
http://www.reddit.com/r/askscience/comments/y33j4/physics_nuclear_fusion/
|
{
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"text": [
"Mass and energy are the same thing. Think of rest mass as energy that is \"trapped\" in one place. Some of this \"trapped\" energy is freed in the D-T fusion reaction.",
" > where do the matter destroyed by the fusion go?\n\nWhat destroyed matter? You start with a Deuterium atom (p + n) and a Tritium atom (p + 2n) and end with an alpha particle (2p + 2n) and a free neutron (n): two protons and three neutrons go in; two protons and three neutrons come out.\n\n > Wikipedia says that the Neutron is \"freed\" in the reaction\n\nThat's what I just said as well.\n\n > but in my opinion you actually reduced some matter to an energy status.\n\nI really wish I had a better way to say this, because I find myself saying it an awful lot and I think it offends people, but your opinion isn't relevant to this discussion. All that's relevant is what our theories predict and what experiments reveal, and on this they agree.\n\n > Can matter and energy be the same thing\n\nEnergy isn't a *thing*, it's a quantity (of certain systems) that can be measured. Things *have* energy.",
"E=mc^2\n\nThis is why nuclear fission reactions are so violent. Mass can be converted to energy and when released that conversion scales the mass by the speed of light squared. The same occurs in fusion. An interesting thing about atoms is that the mass of the whole does not equal the mass of its parts. This difference is described by the equation above and we can measure the energy put out by a reaction to prove it's true. "
]
}
|
[] |
[] |
[
[],
[],
[]
] |
|
im254
|
Can insects eventually evolve into higher, more intelligent lifeforms?
|
Why haven't they done this already? The Earth was dominated by reptiles, now mammals... why not insects next?
|
askscience
|
http://www.reddit.com/r/askscience/comments/im254/can_insects_eventually_evolve_into_higher_more/
|
{
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"text": [
"Sure, why not.\n\nWhy they haven't? They've got it pretty good already, survival wise. Insects are already some of the most \"highly evolved\" things out there, with some extremely sophisticated strategies in play.\n\nEvolution doesn't go \"forward\" to \"more intelligent\" species. Evolution goes towards what is immediately useful for survival.",
"Your question presumes that the world is dominated by mammals, but by all measures of biomass, productivity, and evolutionary longevity, insects have been much more successful than mammals.\n\nEDIT: I also think you have a flawed view of evolution. Modern insects are quite advanced evolutionarily, with many examples of highly derived features. Further, evolution doesn't have any \"goal\" in mind beyond encouraging survivability of species. Your question is akin to asking \"I think humans would be better if they could also see in infrared. Why haven't humans evolved infrared vision?\"\n\nThe wikipedia page on evolution gives a great rundown of the concept, as well as common misconceptions.",
"I believe a big problem is lack of size for a large brain. Insects don't have lungs; they absorb oxygen through diffusion pores in their bodies, which severely limits their size. So they would need to evolve another way to increase their size, and there doesn't seem to be selection pressure for that right now. ",
"(1) Insects are already \"higher\" life forms by most metrics. If you use the broadest possible definition of \"mammal\", insects have been around for 100 million years longer than mammals. If you use a more realistic definition of \"mammal\", then insects have been around 275 million years longer. We don't have any right to feel superior on that basis. \n\n(2) It seems doubtful that insects will ever evolve to be significantly more intelligent than they already have. \n\nWithout major changes to their anatomy and physiology (such that they would no longer be \"insects\"), they can't be hugely larger than they are now (say, couldn't realistically weigh more than a guinea pig, or if we want to stretch it, more than a cat.)\n\nA brain has to be a certain minimum size to be intelligent (why you don't see too many guinea pigs or cats with human-level intelligence), so intelligent insects are right out. "
]
}
|
[] |
[] |
[
[],
[],
[],
[]
] |
|
1stbwf
|
how a rubik's cube can be solved using a set pattern each and every time.
|
I know that Rubik's cubes have certain patterns of moves you can use to solve them, but how is this possible with the billions of possible configurations of a Rubik's cube? How does one set pattern or a couple of patterns work for every possible combination?
Thanks! :D
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/1stbwf/eli5_how_a_rubiks_cube_can_be_solved_using_a_set/
|
{
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"text": [
"They aren't. What professional solvers have are set patterns to 'fix' particular parts of the cube, and then they fix the cube piece by piece.",
"You're refering to solving a Rubik's Cube with [Macro-operators.](_URL_0_) Macro-operators are sequences of moves that will always move part of the cube into the desired position without messing up the positions of any other parts of the cube. This allows you to split up the problem of solving the Rubik's Cube into a set of several 'sub-problems', for example:\n\n1. Solve the top cross\n2. Solve the top corners\n3. Solve the middle layer\n\nand so on. Each sub-problem has it's own macro-operators for solving it. Because macro-operators don't mess up other parts of the cube, you can solve the sub-problems 1 by 1 and end up with a solved cube."
]
}
|
[] |
[] |
[
[],
[
"http://www.dtic.mil/dtic/tr/fulltext/u2/a221571.pdf"
]
] |
|
60b4b2
|
Did Hitler ever have any plans to build a colosseum esque building?
|
Considering his fascination with the roman empire.
I know he wanted to build gigantic buildings in Berlin, he hated Jews enough to create a Gladiator like theater. But maybe the Germans didn't?
Perhaps it's a bit of a odd question, or i have just watched 'gladiator' too recently, this question has me fascinated for the last couple of days though.
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/60b4b2/did_hitler_ever_have_any_plans_to_build_a/
|
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"In terms of fights to the death? No. You seem to have the idea that the Nazis wanted to make a spectacle out of the murder of the Jews. They certainly wanted to make a spectacle out of their opposition to the \"Jewish conspiracy\" - for example, the widely publicised boycott of Jewish-owned businesses - but the idea of having gladiatorial fights was never considered.\n\nHowever, Albert Speer's plans for the gigantic buildings you mention included a stadium that would seat 405,000 people, in addition to two enormous parade grounds - to be named the Zeppelin Field and (appropriately enough) the Mars Field. These could be considered akin to the Colosseum in that they would be enormous public spaces for shows, contests and other, similar events.\n\nSource: R.J. Evans, *The Third Reich in Power*, Evans himself citing several primary sources including Speer's memoirs."
]
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[] |
[] |
[
[]
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3ec5yh
|
why did the greece government all the sudden vote for austerity measures? didn't the people vote no? does their vote not count? how does this work?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/3ec5yh/eli5why_did_the_greece_government_all_the_sudden/
|
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"The referendum in Greece to which Greek voters voted \"no\" was a symbolic gesture that Alexis Tsipras (the prime minister) thought would give him leverage in negotiations with creditors. To be blunt, it did not. Greece ultimately needs the bailout money and the EU more than they need to avoid austerity. It is rumored that EU leaders told Tsipras that Greece would go it alone, geopolitically, if it chose to abandon the Euro and that the EU would not rush to their aid if, say, Turkey were to grow belligerent. \n\nInstead of leading his country immediately into a painful collapse of the economy and financial system and an uncertain future, Tsipras and some of his colleagues chose to back down. Opposition parties in the Greek parliament are supporting the agreement while about half of the Syriza coalition is rebelling. It's very likely that there will be new elections once things have calmed down more.",
"So, here is the situation.\n\nGreece owed money to private investors. To save the Euro's reputation, Germany took over that debt in a hostile takeover, buying it out during the 08 crash and assuming responsibility.\n\nNegotiations had been ongoing. Greece voted 'no' to a specific package of Austerity suggested on a specific day. Because of that, that exact package can't be used.\n\nSo, Germany gave Greece a choice. They said \"Alright, you can leave Europe, print drachma or declare bankruptcy or whatever you need to, and come back later when things are sorted out\" or 'You can agree to this package of Austerity that's different enough from the last one that the referendum doesn't apply to it'. The new package being substantially worse.\n\nGreece was supposed to leave Europe. Everyone thought that Tsipras had a plan to do so and that all of this was about posturing surrounding the leave. Merkel gave him an ultimatum that would have made it easy for them to leave Europe politically, and in 5-10 years to come back. \n\nBut apparently Tsipras was only bluffing, and expected Germany to relent after the referendum. He didn't understand that the Germans were overwhelmingly against a better deal. Maybe he got greedy after realizing that it's better to be the head of an Austerity state than a poor country. \n\nMoving forward, France and Germany are discussing greater centralization to prevent another Greek-like crisis, with stricter borrowing limits set into EU policy and a representative EU parliament capable of voting on EU-wide economic policy to make it more representative. The details are still hard to decide. France and Germany have always vied for control over Europe - the EU was meant to be a way for them to share power and integrate. Germany leads a block of countries that want to keep Europe highly autonomous but with debt controls and more limited immigration, and France leads a block of southern European states that are flooding with refugees and need greater integration and support to cope, including an EU-wide representative parliament with the power to legislate and levy taxes to spend money on EU-wide issues such as the refugee crisis.\n\nIt remains to be seen how that will play out, but for now, Greece's choices are to either impeach Tsipras, leave Europe, and sort their mess out, or to deal with the only Austerity package that wasn't invalidated by the referendum and hope that the IMF's struggle to force Germany to postpone their debt repayments for 40 years goes through."
]
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[],
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||
5ribp8
|
why is the kkk still allowed to exist?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/5ribp8/eli5_why_is_the_kkk_still_allowed_to_exist/
|
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"text": [
"Freedom of speech prevents the government from discriminating against people who hold different - even objectionable - beliefs. Threats are where the line is drawn. People are free to hate other people as long as they do not threaten.",
"There's danger in limiting free speech. Yes, the KKK is pretty much universally reprehensible. But how do you word a law as to draw the line on free speech without giving the government the ability to decide for itself what is and is not acceptable speech? What if Donald Trump decided that any speech criticizing him was not acceptable?\n\nRight now your right to free speech ends when you incite violence. The KKK isn't telling people they should go out and kill black people anymore, so while their message is racist, it has not elevated to the point of being illegal.",
"Because we decided that we would prefer having an evil organization like the KKK rather than letting the government decide what speech is acceptable or unacceptable.\n\nIf you let the government decide to prohibit people who say \"evil\" things, what other organizations do you think they would declare to be \"evil?\" Abortion providers? Gun-control advocates? Anti-war protestors?\n\nOur newest President tells blatant lies and then throws a tantrum when people point out the fact that he is lying. What do you think he would do if he had the power to determine what people can and cannot say?"
]
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[] |
[] |
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[],
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2q7sk2
|
Gavrilo Princep lived untill 1917, did he ever voice his opinion on the war?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/2q7sk2/gavrilo_princep_lived_untill_1917_did_he_ever/
|
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"text": [
"Gavrilo Princip wrote a poem in his prison cell. There is a [link in Serbian](_URL_1_).\n\nBelow is my impromptu translation of the poem\n\n\n\nSarajevo 1914\n\n\n\nSlowly the time is dragging\n\nAnd there is nothing new\n\nToday is same as yesterday\n\nTomorrow will be too.\n\n\nAnd instead in war\n\nWhile battle trumpets are crying\n\nHere we are in a casamate\n\nChains on us are rattling.\n\n\nEvery day is the same life\n\nTrampled, stomped, crushed\n\nI am not an idiot\n\nThis is death for me.\n\n\nThe truth said [Žerajić](_URL_0_) before me\n\nWho wants to leave let him die\n\nWho want to die let him live.",
"It looks like [a similar question was asked before](_URL_0_). It would be nice to see some more info or verification of those answers, but hopefully that's a good starting point."
]
}
|
[] |
[] |
[
[
"http://en.wikipedia.org/wiki/Bogdan_%C5%BDeraji%C4%87",
"http://www.telegraf.rs/vesti/1132690-jedina-sacuvana-pesma-gavrila-principa-ove-stihove-je-noktima-urezao-na-zid-zatvora"
],
[
"https://www.reddit.com/r/AskHistorians/comments/29dvmf/considering_the_assassin_of_franz_ferdinand/"
]
] |
||
4jylr9
|
why do companies still put the "as seen on tv" log on their merchandise? doesn't the logo represent "cheap" in american culture?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/4jylr9/eli5_why_do_companies_still_put_the_as_seen_on_tv/
|
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"Not to that product's target demographic. That demographic thinks, \"Hey, that is that awesome vegetable peeler I saw on TV! It worked great; I should buy it!\"",
"There's an as seen on TV store in my mall. It's always packed. Never been in there though. ",
"In a word: Yes, the \"As Seen On TV!\" logo often *does* represent a low-quality purchase.\n\nStrangely enough, though, it doesn't matter.\n\nThere's an interesting [psychological effect](_URL_1_) that marketers tend to use to their advantage. When presented with an array of similar options for products or services, humans will almost always choose the ones with which they are most familiar. This is true regardless of whether a potential customer consciously assesses quality or not, and it can even override past negative experiences. Catchy slogans, jingles, recognizable characters, and attention-grabbing designs are all used to capitalize on this phenomenon, with the end result being better sales.\n\nWhen a company includes that \"As Seen On TV!\" logo on their product's packaging, they aren't making a statement about quality. What they're really doing is saying \"Hey, you know about this!\" It evokes that feeling of familiarity, which gives the item a significant advantage over others of a similar nature. In fact, [most advertising](_URL_0_) is meticulously designed to make consumers aware of things they can buy. Many commercials go the extra mile and make their subjects seem appealing in some way (particularly in the case of food advertisements), but that recognition factor is one of the most important goals.\n\nIn other words: Reminding someone that they've already seen a product on television - regardless of what they thought about it - goes a long way toward making a sale.\n\n**TL;DR: Familiarity breeds consumerism.**"
]
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|
[] |
[] |
[
[],
[],
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"http://vivaldipartners.com/pdf/BrandFamiliarity.pdf",
"https://www.psychologytoday.com/blog/sapient-nature/201201/familiarity-breeds-enjoyment"
]
] |
||
4mpf60
|
why is menthol "cold"?
|
Edit: This blew up a lot more than I thought it would.
To clarify, I'm specifically asking because the shaving soap that I used today is heavily mentholated, to the point that when I shave with it my eyes get wet.
_URL_0_ This soap, specifically. It's great. You should buy some.
It's *cold*™
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/4mpf60/eli5_why_is_menthol_cold/
|
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"The people saying it's because of evaporative cooling are wrong. Menthol's boiling point is 212 Celsius, much warmer than your body. \n\nMenthol isn't really cold, it just tricks your body into thinking it is. There's a type of nerve cell that responds to things like temperature, pressure, pH, etc. Some of these cells have what's called a TRPM8 receptor on their surface. When menthol comes into contact with a TRPM8 receptor it binds to it, which makes the affected cell open an ion channel that admits sodium and calcium ions into the cell. This in turn causes the nerve cell to send a signal to the brain that the brain interprets as coldness. A similar receptor, TRPV1, is why the capsaicin in hot peppers feels 'hot'.\n\nBasically, menthol binds to a receptor on certain temperature-sensitive nerve cells, causing them to fire, and your brain interprets this nervous activity as coldness.\n\nEDIT: Okay, evaporative cooling probably does have something to do with it, and it isn't necessary for a substance to reach it's boiling point to evaporate. However, I'm willing to bet that the cooling sensation is caused overwhelmingly by TRPV8 activation.\n\nEDIT: JESUS CHRIST YES VAPOR PRESSURE I GET IT",
"If you combine menthol and capsaicin in water (so the pure forms of the molecule), is it possible to get to an exact ratio where the coldness feels the same as the hotness?\n\nWill your skin feel like it's both freezing and burning or will it feel normal?",
"It's the same as capsaicin being hot just cold. It triggers a nervous system response that makes you feel cold when it's not the case",
"I hope this isn't a stupid question, but could someone explain whether it is actually possible to get a cold from using menthol-heavy shampoo? I and several family members have somehow developed colds right after some serious shivering (in the dead of summer) caused by this awful, awful torture-shampoo. \n\nBasically, is it possible that these chemicals can mimic your brain's perception of cold so accurately, they actually suppress your immune system like *really* being in a cold environment does, causing dormant bugs to flourish? Does your body just switch on the *full* response to coldness?",
"Easier ELI5:\n\nEverything is an illusion. Your brain only senses reality through the nerves.\n\nLike a pain killer, menthol binds to your temperature sensors to send information to your brain that is interpreted as a feeling of cold. In a similar way that a pain killer binds to your pain sensors to block the signal of pain.",
"your tongue and skin has little blobs of protein on it called receptors. when the temperature changes, these change shape and send a signal to your brain. some receptors detect high temperatures. these bind to capsaicin to tell your brain its hot. some receptors detect low temperatures. menthol can bind to them and make them trick your brain into thinking its cold"
]
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[] |
[
"http://www.queencharlottesoaps.com/Vostok_p_31.html"
] |
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bexzt6
|
where do our eyes focus when sleeping?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/bexzt6/eli5_where_do_our_eyes_focus_when_sleeping/
|
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"Your eye focus is determined by the activity of the [ciliary muscle](_URL_0_). When it contracts, this warps your lens and makes it longer than it is wide, and you can see things up close. When it relaxes, the lens warps and becomes thinner, and you can see things at a distance. \n\nJust like all the other muscles in your body, the ciliary muscle is relaxed when you are asleep. So to answer your question, they focus for \"distance\" vision. \n\nAs for the 20/20/20 rule, that doesn't have to do with focus. Eye strain from using computers and reading isn't that your eyes need to change their focus to stop being stiff or whatever, it's that when you're focused on a computer or a book or anything else up close you stop blinking. When you look away for a while, you remember to blink. That's why it helps."
]
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]
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||
1j5n2o
|
How common was filming from aircrafts during WWII?
|
I watched the film Red Tails last night, George Lucas's take on the experience of black US airmen in 1944 Italy. Whilst I'm sure it's full of inaccuracies, one thing that I was left wondering is how common was filming from aircrafts during the war? In the film, after each mission the airmen watch back clips from their last mission on an old reel projector.
I'm presuming this is mostly a dramatic device for narrative reasons... But did this ever happen? If so, how common was it? How many planes carried cameras?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/1j5n2o/how_common_was_filming_from_aircrafts_during_wwii/
|
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"text": [
"it was not extremely common but not usual for some planes to have a [gun camera](_URL_0_). The camera is triggered to start recording when the pilot pulls the trigger and fires planes guns and stays recording for a short period of time. This footage is used to review the missions and to help train new pilots and or help pilots correct their mistakes. It was also more heavily used on ground attack aircraft so that after the missions they could slow the footage down and count how many tanks, planes, trains etc they actually hit during the mission and estimate success of the mission"
]
}
|
[] |
[] |
[
[
"http://en.wikipedia.org/wiki/Gun_camera"
]
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|
3je7cw
|
why don't laptops use simcards?
|
As the title says.
In most major cities, the mobile data net is fast enough to handle data transmissions - hell, where I live, my phone (with wifi off) is faster than my own 100/50mbps network.
Why don't laptops come with a place to put a simcard, just like a phone?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/3je7cw/eli5_why_dont_laptops_use_simcards/
|
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"Because you just have to buy [one of these](_URL_0_) or [one of these](_URL_1_). So, on the manufacturing aspect, they don't have to add a port and the functionality for no reason.",
"The simcard doesn't work by itself, it requires a *cellular radio chip* and an antenna. These add significant cost to the product. Since most laptop users don't want it, it's not worth building in.\n\nA good option instead is to use your mobile phone, either as a mobile hotspot or (using less power) tethered to your USB port.",
"In addition to what the other users have said: some laptops (especially those geared towards business use) do ship with cellular cards built in, which you are then able to pop a sim card in to and use for mobile Internet. If I remember correctly, Lenovo's Thinkpad line is one example of a brand that comes with a cell card option. At least it used to be: I have a Thinkpad at home that has a slot for a cell card, but I've never had need to add one. "
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[] |
[] |
[
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"http://mb.cision.com/Public/MigratedWpy/85065/699656/9a780df5c46cf19e_org.jpg",
"http://www.verizonwireless.com/internet-devices/ellipsis-jetpack-mhs800l/"
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frn8st
|
We found several more SARS related coronaviruses in bats. Could we create vaccines for them now using these strains that would be effective if they ever transferred to humans?
|
askscience
|
https://www.reddit.com/r/askscience/comments/frn8st/we_found_several_more_sars_related_coronaviruses/
|
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"Making a vaccine against a virus that hasn’t actually infected any people isn’t realistic or practical.\n\nThe last and most important phase in testing a vaccine is to give it to a lot of people, to see if it prevents them from catching the disease the vaccine is supposed to protect against.\n\nYou can’t do this if there’s no actual disease in the community.\n\nIt’s why the development of the SARS vaccine was never completed; by the time it was almost ready for large human trials, SARS had died out."
]
}
|
[] |
[] |
[
[]
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||
pmbbj
|
How many plants would I need to have in a sealed room with me to never run out of oxygen?
|
Is there a specific plant that is best at the process of creating oxygen?
Edit:
Factors for a specific scenario:
Unlimited access to water and sunlight (source of energy) The soil has all necessary nutrients. (Optimal conditions)
An average male at 80 kilos at 180 cms and age 20.
The person has no threats that will cause them to need to increase their consumption but the risk should still be considered ensuring a few extra plants are in the room.
( These are factors I assume change oxygen production and consumption, I could be wrong)
|
askscience
|
http://www.reddit.com/r/askscience/comments/pmbbj/how_many_plants_would_i_need_to_have_in_a_sealed/
|
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"**tl:dr - answer: 17.5 trees** - madmaxola\n\nOne of the things you have to be concerned about is that the room itself, depending on its material, will absorb a large amount of potential oxygen unless the surfaces have been cured. I know I've seen some research done on this...\n\n[I found this on Yahoo Answers](_URL_1_) which led to [some information on the Biosphere II project] (_URL_4_) (ignore the hideous colors) that explains: \"A vast majority of Biosphere II was built out of concrete, which contains calcium hydroxide. Instead of being consumed by the plants to produce more oxygen, the excess carbon dioxide was reacting with calcium hydroxide in the concrete walls to form calcium carbonate and water.\n\nCa(OH)2 + CO2 -- > CaCO3 + H2O\"\n\nFrom NASA: [the average man needs 0.63 kg of oxygen per day] (_URL_3_) (near the bottom of the page). They estimated 17.5 trees per person, so you need to find the equivalent number of house plants. \n\n[Or, as another source suggests, algae:](_URL_0_) \"A net production of 500 g to 600 g of dry algae per man per day is required for oxygen regeneration, CO2 absorption, water regeneration, nutrient removal and organic waste treatment.\"\n\nThis is mostly relevant: [scientist seals himself in a box with plants.](_URL_2_) It's not a research paper, but it has some information.\n\nAs for all those who are commenting on the validity of the information contained in this post due to where it was obtained: rather than judge the origin of the information, judge the information itself - if there is incorrect information, please let me know so I can fix it. Information.\n\n*I edit for science*",
"Your best bet is algae. I couldn't find good numbers on the amount needed per person, but it's going to depend on species and lighting.",
"Watch this TED talk: \n\n_URL_0_",
"unlimited water...the water would bring in oxygen as well",
"Kind of related to this, but what plant/tree/algae removes the most CO2 from the atmosphere? ",
"_URL_0_ Watch this documentary.\n\nThe presenter gets into a sealed box with a bunch of plants for 24 hours and sees how his body reacts and if the plants can supply enough oxygen. Its around 13 mins in.",
"[Here is your answer.](_URL_0_) As tested in \"the healthiest building in New Delhi\", leading to a 20% productivity boost.\n\nYou need:\n\n* areca palm - 4 shoulder height plants per person\n\n* mother-in-law's tongue - 6-8 waist-high plants per person\n\n* money plant - does not mention how many you need\n\nHe specifically says you could be in a sealed bottle with these plants and not die.",
"It's been done in the [Eden project, UK](_URL_0_)",
"Kind of related to this: why do humans exhale CO2? Where does the extra carbon come from?",
"Problem: plants don't just produce oxygen, at certain times they ALSO consume it. In general it's advised you dont keep too many plants where you're going to be sleeping in a closed room - at night plants release CO2 and consume O2. \n\nJust an aside.. \n\n(source: preliminary bio undergraduate class) ",
"Somewhat relevant: \n\nMy mom is a patent agent, and one of the patent applications that came across one of the partners' desks at her firm was an application for a dome that was worn on a person's head. Inside the dome were, I believe, cacti arranged on shelves. Wasn't sure I would be able to find it, but I found it first try: [Enjoy](_URL_0_)",
"Is there a way to possibly make a gas mask type apparatus to convert exhaled CO2 directly into oxygen and some other byproduct?",
"I went and looked in my copy of Spaceflight Life Support and Biospherics (by Peter Eckart), and found it had this to say:\n\n* You can expect 0.636-1kg/man-day of Oxygen consumption, depending on activity levels. (Best to assume the higher limit.)\n* Oxygen production is directly proportional to the amount of plant *growth*, not the amount of plant biomass present. A small but fast-growing plant produces more oxygen than a large but slow-growing tree.\n* Humans produce about 0.85 moles of CO2 per mole of O2 consumed.\n* Plants consume about 0.95 moles of CO2 per mole of O2 produced.\n* Plants filter some trace gasses, but emit a variety of others as bi-products of their metabolism.\n* Wheat produces about 2.7kg/m^2 of biomass every 8 weeks.\n\nCO2 is about 44g/mole, O2 32g/mole. So for every kg of O2 produced by plants, ~1.3kg of CO2 will be consumed, but for every kg of O2 consumed by a human, only ~1.2kg of CO2 will be produced. So you're going to have to find a source for ~100g/day of CO2. One way to do this is to recycle excess plant biomass somehow. Also, since you're essentially sealed in a box with these plants, you're going to have to filter the trace gasses the plants produce from the air, or else they'll just build up until they're lethal. Or produce headaches, hallucinations, or whatever. It's not really wise to breath high concentrations of any complex organic molecules, no mater how \"natural\" they are.\n\nNow, the next bit is a very rough estimate based on the above: since you need 1kg of O2/day, the plants will have to grow by about 1.3 - 1.0 = 0.3kg/day. (Am I forgetting any mass inputs here? H2O maybe?) Given the rate wheat grows, you could manage that with about 6 or 7 square meters of wheat (in ideal conditions). You'll probably need more (double?) to continuously recycle some of the biomass grown back into CO2 to keep the atmosphere in your box balanced. For comparison, you need about 40 square meters of wheat and other plants to keep one person fed continuously, according to Eckart.\n",
"you know, before you ask a question here, you should really search. this exact same question was asked about 2 months ago, and the exactly same \"top\" answers were given. ",
"it takes 7 FULL GROWN TREES to process the amount of Co2 that a single human produces into an equal amount of oxygen.",
"Just wondering, but if you had access to unlimited sunlight and water, couldn't you create enough oxygen for yourself without having to involve plants?",
"What area of study would I pursue if I wanted to learn more about this kind of thing and work towards developing my own 'biosphere'?",
"This is a short list of the best air cleaning (toxin removing & oxygen producing) plants which are also safe for your pets if they decide to nibble on them.\n\n+ Spider Plant (Chlorophytum comosum)\n\n~ fast growing\n\n~ hanging plant, so have to have off the ground\n\n~ lots of oxygen\n\n+ Dracaena reflexa var. augustifolia\n\n~ AKA Red-edged dracaena (Dracaena marginata)\n\n~ grows up like a tree w/ a woody stalk, up to 10 feet tall\n\n~ plants edges are sharper than spider plants\n\n+ Weeping Fig (Ficus benjamina) tree\n\n~ grows slower, but beautiful tree\n\n~ good for larger spaces if it's been growing a while.",
"I read somewhere that a 40m2 lawn can make enough oxygen for one person. Will find a reference for that once I get onto a computer...",
"This guy figured it out with NASA and had some amazing results implementing his findings: _URL_0_\n\n",
"Here you go: [Ted Talk](_URL_0_)",
"One other thing you need to take into consideration is that in the dark plants will be respiring and using up oxygen as well, while I don't know how significant this will be in the given scenario it does become an issue in small water bodies with large algae blooms\n",
"Also, would you make enough CO2 for the plants to exchange back to oxygen?",
"According to this [TED talk](_URL_1_), one person can survive with just 3 species of common houseplants in fairly small quantities: 4 [Chrysalidocarpus Lutescens](_URL_0_) plants, 6-8 [Sansevieria Trifasciata](_URL_3_) plants, and an unspecified number of [Epipremnum Aureum](_URL_2_) plants. I haven't fact checked this, but it's a really fascinating TED talk, and I would like to know if someone could evaluate his claims here. He has used these plants in a building in Delhi and improved the air quality.",
"Here is a [Ted talk]( _URL_0_) on the subject. ",
"The question then becomes how long till the plants die without sun to process the carbon dioxide?",
"NASA has a [CELSS](_URL_0_) project that studies renewable life support via plants and other biological methods. (There is a partner project that does it all with chemistry.) Their standard test chambers hold 9 square meters of growing space. Wheat is the baseline crop. In rough numbers, 9 m^2 of wheat will provide...\n* oxygen for 1 person.\n* water for 1/2 person.\n* food for 1/6 person.",
"Was this Ted talk [referenced](_URL_0_)? "
]
}
|
[] |
[] |
[
[
"http://cedb.asce.org/cgi/WWWdisplay.cgi?7000907",
"http://answers.yahoo.com/question/index?qid=20090116111953AAeaWw5",
"http://www.dailymail.co.uk/sciencetech/article-2038180/TV-scientist-suffers-blinding-headaches-experiment-living-airtight-box-surviving-solely-oxygen-emitted-plants-comes-end.html",
"http://settlement.arc.nasa.gov/Contest/Results/96/winner/seis.html",
"http://biology.kenyon.edu/slonc/bio3/2000projects/carroll_d_walker_e/whatwentwrong.html"
],
[],
[
"http://www.ted.com/talks/kamal_meattle_on_how_to_grow_your_own_fresh_air.html"
],
[],
[],
[
"http://www.bbc.co.uk/iplayer/episode/b01bywvr/How_to_Grow_a_Planet_Life_from_Light/"
],
[
"http://www.ted.com/talks/kamal_meattle_on_how_to_grow_your_own_fresh_air.html"
],
[
"http://www.dailymail.co.uk/sciencetech/article-2035007/Scientist-spend-48-hours-airtight-box-plants-alive.html"
],
[],
[],
[
"http://www.google.com/patents?id=-n4uAAAAEBAJ&printsec=abstract&zoom=4#v=onepage&q&f=false"
],
[],
[],
[],
[],
[],
[],
[],
[],
[
"http://www.ted.com/talks/kamal_meattle_on_how_to_grow_your_own_fresh_air.html"
],
[
"http://greenspaces.in/blog/ted09/"
],
[],
[],
[
"http://en.wikipedia.org/wiki/Dypsis_lutescens",
"http://www.ted.com/talks/kamal_meattle_on_how_to_grow_your_own_fresh_air.html",
"http://en.wikipedia.org/wiki/Epipremnum_aureum",
"http://en.wikipedia.org/wiki/Sansevieria_trifasciata"
],
[
"http://www.ted.com/talks/kamal_meattle_on_how_to_grow_your_own_fresh_air.html"
],
[],
[
"http://en.wikipedia.org/wiki/Controlled_Ecological_Life_Support_System"
],
[
"http://www.youtube.com/watch?v=gmn7tjSNyAA&feature=youtube_gdata_player"
]
] |
|
56c18d
|
why do we drive on a side of the car? wouldn't it make more sense to drive from the center?
|
Title.
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/56c18d/eli5_why_do_we_drive_on_a_side_of_the_car_wouldnt/
|
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"Early cars did this. It wasn't until later that it was shifted to the side.\n\nUltimately it was moved to the side, with early inconsistency. The logic was probably greatly influenced by increased passenger comfort/space, but was argued as either aiding you in avoiding oncoming traffic, or aiding you in not falling into the ditches that were always to the side of roads. Needless to say, the \"oncoming traffic\" concern prevailed.",
"You need to get out of the car at some point so sitting in the center would be awkward. Also it might make it hard to determine the exact position of the side passing oncoming cars, so there is a good reason. Also you need to fit another person in there so... You going to split them in two?",
"Driving on the side allows you to see oncoming traffic easier when attempting to pass another vehicle."
]
}
|
[] |
[] |
[
[],
[],
[]
] |
|
20mg15
|
How common were prison escapes in the middle ages? What are some notable escapes and attempts?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/20mg15/how_common_were_prison_escapes_in_the_middle_ages/
|
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"Duke Kestutis, pagan Duke of Trakai, brother and close ally to Grand Duke Algirdas of Lithuania escaped from Marienburg, where he was held by the Teutonic Order 1361.\n\nBeing an important nobleman and someone the Teutonic Order hoped to convert to christianity, Kestutis was kept in relative comfort and not in cell far down the dungeon. Still, his escape was, according to German chronicler Wigand of Marburg, quite daring and quite demanding.\n\nKestutis, who was supposedly 65 at the time, but in fine physical shape (he would go on to lead Lithuanian military campaigns 1363 and 1370, the latter at the age of 74), escaped from his cell or room through a locked door, climbed up through a chimney, stole a Teutonic Knight's cloak/mantle and simply went out in the courtyard, mounted the Grand Master's own horse and rode out of Marienburg (which was the largest and strongest castle in Europe) like no-one's business.",
"Maybe not completely what you are looking for, but in 1618, just after the middle ages, Hugo Grotius, a member of the States General, the government of the Dutch Republic was among those imprisoned by the Remonstrants, who staged a coup and overthrew the States General. \n\nGrotius had it fairly well in his prison, he was allowed to write, correspond with outsiders and had access to books, but he was scared the authorities would revisit his case and impose a harsher punishment, they had executed some other members. So he decided to escape.\n\nIn March 1621, his wife shipped a large chest to him. He then had it sent away, pretending it contained books. In reality, he hid in it and had himself shipped away. The escape attempt was succesful and he fled via Antwerp to Paris where he rejoined his family. \n\nThis escape attempt is fairly famous in The Netherlands and you won't find many people who don't know about the bookcase of \"Hugo de Groot\", as he is known there.\n\n[Source.](_URL_0_)",
"Not a \"prison escape\" as such but he was a prisoner at the time...\n\nKing Henry III of England was facing a rebellion led by Simon de Montfort, the Earl of Leicester, Henry's own brother-in-law. The king had become unpopular with the baronial class due to his costly building projects (most notably the construction of Westminster Abbey as we know it today) and an unsuccessful attempt to intervene on the Pope's behalf in Sicily. The rebellious barons also opposed the influence over the king, both actual and perceived, that certain \"foreigners\" had. I'm not quite sure what constituted a \"foreigner\" in the mid-13th century, as de Montfort himself was French-born and never set foot on English soil, that I know of, until he was over 20 years old.\n\nAnyways!\n\nPrince Edward (would later become King Edward I of England, or Edward Longshanks) was taken as a hostage after the royalist defeat at Lewes in order to ensure that Henry III abided by de Montfort and the barons' demands.\n\nFrom the admittedly little I've read (I'm going off of Simon Schama's A History of Britain, 3000BC-1603AD, I've just read up to Edward's coronation), it sounds like his imprisonment was pretty lax, and he was allowed visits from friends and learnt of the movements of royalist armies (de Montfort still had plenty of enemies, even with the king defeated and the prince a prisoner).\n\nSo Edward was out on a hunting trip, under the supervision of his captors. He asked to inspect their horses and proceeded to run them into the ground, exhausted. After tiring out all the horses but one, he took the last one and fled to freedom.\n\nJust five months later, in August 1265, Edward defeated de Montfort's army at Evesham. With de Montfort killed in the course of battle, the leader of the civil war was dead and much of the opposition to the king and prince disintegrated.\n",
"I think this question is premised on a misconception; the idea that something analogous to modern prisons existed in the middle ages. The governments of the various kingdoms, towns, etc. in the middle ages would be much less centralized and generally much less powerful than our modern national, state, and local institutions. Local law enforcement would generally have been handled by local volunteers at the manorial level, and by a sheriff or similar official appointed or approved by the king at the shire or county level. \n\n\nWith the number and resources of local law enforcement being limited, there was no money or staff to run a prison that would hold someone for years at a time. A large town or castle would likely have some cells, but these would function as a jail. That is, it would be a temporary place to hold a prisoner before sentencing was carried out; not somewhere to hold someone as their punishment. The average punishment for minor crimes in the middle ages would involve some form of public shaming or financial punishment; time in the stocks, a fine, or restitution to the victim. For more serious crimes, the offender might be branded as a thief, have their hand cut off, or be whipped or flogged. For the most serious crimes, the death penalty was most common. \n\n\nThe thread that ties all these punishments together is that they could be performed immediately following trial, and at little cost in time and money. You would capture the criminal, sentence them, flog them (for example), and then let them go on their way. No costly business of maintaining a roof over their head, feeding them, guarding them, etc. The modern conception of a prison, a large building that people are sentenced to live at for years at a time as their punishment, would not start to be common until the late 1700s. ",
"I don't have detailed sources nearby, but Sir Thomas Malory, author of the deservedly famous *Le Morte d'Arthur,* was in and out of prison for much of his life. Not terribly surprising that he'd be put in in the first place, given that he was a politically active man during the Wars of the Roses, but he did do rather more escaping than your average medieval prisoner. If I recall correctly, he even swam across a moat in one of his escapes. Luckily for posterity, he eventually found himself in the Tower of London, a prison both escape-proof and well stocked with books. It was there that he wrote his *magnum opus*.",
"I hope someone with more knowledge can verify and add to this, but didn't Napoleon escape exile, return to France, gain power, and attempt to take over Europe again?"
]
}
|
[] |
[] |
[
[],
[
"http://www.historyoflaw.info/hugo-grotius-escape-from-prison.html"
],
[],
[],
[],
[]
] |
||
22alrw
|
why don't civilian police stop truckers?
|
All I ever see is troopers stopping them or sheriffs
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/22alrw/eli5_why_dont_civilian_police_stop_truckers/
|
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"I'm not sure what you mean by \"civilian police\". If you mean *city* police, they do, if truckers break traffic laws. That's pretty uncommon though.",
"City police can pull over any drivers on highways, they just usually leave that part of patrolling to state troopers in most areas.",
"DOT enforcement is usually on our case. ",
"I'm Californian so my answer may be different than the reality in your state: \n\nIn California, local police officers can pull over any vehicle that is breaking the law. Truckers, however, are rarely pulled over by local police for two reasons: 1) Truckers usually are on the highways which local police rarely get onto because the Highway Patrol controls it. 2) Truckers have complex laws regarding tickets and the likes which is why the CHP has it's own division that deals with them, local police usually don't want to get involved. \n\nIf a trucker is clearly breaking the law and being a danger to the public, the local police can and will pull them over. All police officers (sheriff, highway patrolman, cops) are equal in California - they can all pull over and arrest criminals wherever the strike in the state of California. "
]
}
|
[] |
[] |
[
[],
[],
[],
[]
] |
|
53mrtl
|
Stone age Europeans reaching the Americas?
|
So I've seen a decent amount of different newssites post something similar to [this](_URL_0_). But I can't seem to find the original studies or anything about it.
Anyone that knows for sure whether this is the case or not?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/53mrtl/stone_age_europeans_reaching_the_americas/
|
{
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"text": [
"There's always room for discussion, but perhaps these previous topics found through the search function will answer your inquiry.\n\n* [Who are the Solutreans and did they migrate to America?](_URL_1_) by /u/Reedstilt\n\n* [\nWhat evidence is there that Caucasians inhabited the New World, prior to the arrival of Columbus and his men?](_URL_0_) by /u/Reedstilt"
]
}
|
[] |
[
"http://www.independent.co.uk/news/world/americas/new-evidence-suggests-stone-age-hunters-from-europe-discovered-america-7447152.html#gallery"
] |
[
[
"https://www.reddit.com/r/AskHistorians/comments/2lcsto/what_evidence_is_there_that_caucasians_inhabited/",
"https://www.reddit.com/r/AskHistorians/comments/1jrwal/who_are_the_solutreans_and_did_they_migrate_to/"
]
] |
|
2etpn7
|
Do anthropologists agree with Steven Pinker that the average rates of violence in hunter/gatherer societies are higher than peak rates in World War 2?
|
_URL_0_
|
askscience
|
http://www.reddit.com/r/askscience/comments/2etpn7/do_anthropologists_agree_with_steven_pinker_that/
|
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"While not of the quality of a scientific journal article, the following article (by the director of Survival International) does question Pinker's view, giving some examples of how Pinker's views may be flawed. It also links to other sources which take the same opposing view:\n\n_URL_0_",
"The Better Angels of Our Nature certainly is a convincing tome of data and statistics. The arguements I've seen against it have not been nearly as convincing as his book, but I imagine that refuting his data fairly would be a huge task that most people, even in academia, would lack the resources do effectively. ",
"Here's an article about an anthropologist that went to study an uncontacted tribe in Venezuela in 1964: \n\n_URL_0_\n\n\n > Chagnon’s observations led him into dangerous intellectual areas. From his initial contacts with the Yanomamo, he’d noticed how prevalent violence was in their culture. He determined that as many as 30 percent of all Yanomamo men died in violent confrontations, often over women. Abductions and raids were common, and Chagnon estimated that as many as 20 percent of women in some villages had been captured in attacks. Nothing in his academic background prepared him for this, but Chagnon came to understand the importance of large extended families to the Yanomamo, and thus the connection between reproduction and political power.\n\n ...\n\n > Undaunted, Chagnon plunged even further into the thicket of political incorrectness. In a 1988 Science article, he estimated that 45 percent of living Yanomamo adult males had participated in the killing of at least one person. He then compared the reproductive success of these Yanomamo men to others who had never killed. The unokais—those who had participated in killings—produced three times as many children, on average, as the others. Chagnon suggested that this was because unokais, who earned a certain prestige in their society, were more successful at acquiring wives in the polygamous Yanomamo culture. “Had I been discussing wild boars, yaks, ground squirrels, armadillos or bats, nobody . . . would have been surprised by my findings,” he writes. “But I was discussing Homo sapiens—who, according to many cultural anthropologists, stands apart from the laws of nature.”\n\n",
"As a professional anthropologist (but one who does not work in this area), I see excellent evidence for interpersonal violence and war during the last 10,000 years, often at high levels, but very evidence little prior to that.\n\nTwo examples. First, the Saunaktuk massacre:\n\n > The remains of at least 35 individuals (women, children, and the elderly) were recovered from the Saunaktuk site (NgTn-1) in the Eskimo Lakes region of the Northwest Territories. Recent interpretations in the Arctic have suggested a mortuary custom resulting in dismemberment, defleshing, chopping, long bone splitting, and scattering of human remains. On the evidence from the Saunaktuk site, we reject this hypothesis. The Saunaktuk remains exhibit five forms of violent trauma indicating torture, mutilation, murder, and cannibalism. Apparently these people were the victims of long-standing animosity between Inuit and Amerindian groups in the Canadian Arctic. This animosity is explored by examining in detail the skeletal evidence of violence and the rare commodity of an ethnohistory in the form of a local oral tradition. The ethnohistory serves to confirm the conclusions reached from the skeletal analysis. A detailed description of the lesions present on the remains chronicles the tragic events that took place at this site in precontact times.\n\n_URL_2_\n\nAnd second, if you have the stomach for it, this eyewitness account by the English explorer Samuel Hearne of a massacre by arctic Native Americans c. 1771:\n\n_URL_3_\n\nTwo examples do not prove the case, of course, but even critics of Pinker's \"Hobbesian\" view, such as anthropologist Brian Ferguson, admit that rates were high in many (but not all) prehistoric societies:\n\n > The case has been forcefully made archaeologists \"pacified the past\" by not looking for signs of war, or neglecting them when found. Sometimes that has been true. But also true is that in many places and periods, evidence simply does not appear, even when diligently sought--in striking contrast to plenty of other places where war signs are very clear.\n\n_URL_1_\n\nHere is Ferguson's critique of Pinker:\n\n_URL_0_\n\nAs an aside, I see little difference between Ferguson and Pinker: both agree that many societies have warred, and both argue that, nonetheless, humans can choose peace.\n"
]
}
|
[] |
[
"http://youtu.be/2nJaeiOeqRA?t=25m22s"
] |
[
[
"http://truth-out.org/opinion/item/16880-the-case-of-the-brutal-savage-poirot-or-clouseau-or-why-steven-pinker-like-jared-diamond-is-wrong"
],
[],
[
"http://www.city-journal.org/2014/bc0413sm.html"
],
[
"http://www.ncas.rutgers.edu/sites/fasn/files/Pinker's%20List%20-%20Exaggerating%20Prehistoric%20War%20Mortality%20(2013).pdf",
"http://www.ncas.rutgers.edu/sites/fasn/files/The%20Prehistory%20of%20War%20and%20Peace%20in%20Europe%20and%20the%20Near%20East%20(2013)_0.pdf",
"http://www.jstor.org/stable/40316364",
"http://books.google.com/books?id=NcBigmkKFqYC&lpg=PT3&ots=aEvMRybZqi&dq=samuel%20hearne&lr&pg=PT311#v=onepage&q&f=false"
]
] |
|
28rvql
|
the possibility of a world war 3
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/28rvql/eli5_the_possibility_of_a_world_war_3/
|
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"text": [
"Somewhat likely. Russia is pissing everyone off with their Ukraine crap, but mutually assured destruction will certainly keep everyone from firing nuclear arms. The closest the world has been to nuclear war was the Cuban missile crisis of the 1960s in the Cold War.",
"It's doubtful that a war between super powers would happen. Mainly because of the sheer destruction super power countries are capable of. Way too much damage would be inflicted by each side to make it worth it. Nuclear weapons really have changed the world more than people realize. The risk of entire cities being leveled out-weighs any kind of benefit that could be had by engaging in war. Countries like China, Russia and the US have a vested interest in each other financially too. It would be a lose-lose for any country involved. ",
"I think at this point highly unlikely the world is too highly connected and dependent on each other + of course there's the everyone has nukes aspect. It's like at this point that sort of war would have no upside for anyone involved\n",
"Unlikely, in that it would take something catastrophically awful to kick it off. Like, Russia invades Alaska or Iran nukes Jerusalem and rallies other Muslim nations against the West. \n\nWW1 and WW2 were both piles of kindling waiting for a spark to ignite them. Plus, you had various treaties and pacts that lead to \"An attack against X is an attack against Y also\". \n\nNow, the world is so connected that there isn't two major \"sides\" anywhere. Every superpower more or less depends on all the others to a degree. It would take a nation truly go rogue to start something on a global scale."
]
}
|
[] |
[] |
[
[],
[],
[],
[]
] |
||
7qw5l8
|
how can freezing have a "burning" effect?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/7qw5l8/eli5_how_can_freezing_have_a_burning_effect/
|
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"From a feeling point of view, they both set off nerves and can be intense enough to not be able to tell the difference. \n\nFrom a damage point of view they both damage cells and can cause similar looking injuries even though the cause is different. \n\nUnder a microscope burnt and frozen cells look different but at the scale the human eye can see, a patch if destroyed cells can look the same as an entirely different patch of destroyed cells. ",
"Burning and freezing both kill cells by making them a temperature they can't handle. They also kill cells in about the same shape, because temperature changes spread from cell to cell.\n\nSo while the method of killing each cell is different, the outcome is similar. Cells are dead where you burn or freeze them."
]
}
|
[] |
[] |
[
[],
[]
] |
||
148w5o
|
How much would you have to compress a single atom for it to turn into a black hole?
|
Does this question even make sense given the math of the matter?
|
askscience
|
http://www.reddit.com/r/askscience/comments/148w5o/how_much_would_you_have_to_compress_a_single_atom/
|
{
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"text": [
"If you're using a hydrogen atom (i.e., a proton), the Schwarzschild Radius is [2.5 x 10^-54 meters](_URL_0_).\n\nA black hole's event horizon is 3 kilometers per solar mass."
]
}
|
[] |
[] |
[
[
"http://www.wolframalpha.com/input/?i=3+km+*%28mass+of+proton%29+%2F+%28solar+mass%29"
]
] |
|
27xk0l
|
If chewing is the first step in digestion, would you get more energy from a food if you swallowed it before chewing it?
|
askscience
|
http://www.reddit.com/r/askscience/comments/27xk0l/if_chewing_is_the_first_step_in_digestion_would/
|
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"The purpose behind chewing our food is to reduce its size and introduce some initial enzymes (in our spit) that start the digestive process going. If the food isn't chewed enough, the lumps of food are larger and the surface area is smaller, which makes digestion of the food more difficult. That would mean that you'd be *less* able to digest food if you didn't chew it first."
]
}
|
[] |
[] |
[
[]
] |
||
1f0xj0
|
how autotune works
|
I understand that the frequency of a sound wave determines its pitch.
Let's say we have three notes, of 1 second each, and each of different pitches. I understand that if a computer could determine where one note ends and another one starts (which isn't too difficult to do), it could easily speed up the sound wave for each note, repeating it to make sure it still lasts the required amount of time. So if we want to go up by an octave, the frequency doubles, and we'll need to repeat the sound wave twice.
But "real" sounds and voices aren't like that. They're constantly changing their frequency and shape. You can't just speed up a sound wave and repeat it twice - the words would be doubled in speed and repeated!
How is it possible to change the pitch of such a complicated wave shape, while still keeping the shape intact so that they words can still be clearly heard and not sped up? I'm guessing there must be some complicated maths required to do that... or is there a really simple way to do it that I'm missing?
Thank you!
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/1f0xj0/eli5_how_autotune_works/
|
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"text": [
"Well this is really hard to explain like you're five years old because of the advanced nature of the science and technology involved.\n\nI should first say that I don't really KNOW this for sure, I'm not as familiar with the technology but I do work in sound design so I still have a little background and knowledge and this is what I'm basing my post on.\n\nEvery sound has a given frequency, whether it's a sine wave or a more complex waveform like a voice. Imagine a person saying \"AAAAA...\" into a microphone. You can see a repeatable pattern in the waveform when it's presented digitally, on screen. How often this pattern occurs/repeats decides the *pitch* or *tone* of the sound, and the frequency is measured by looking at how often the pattern is repeated in one second (one cycle in one second = 1 Hertz).\n\nBecause there is such a repeatable pattern in a constant sound wave, the auto-tuner can approximate its frequency (and therefore its pitch) by looking at *what* is repeating (the wave cycle itself) and how often, and then corrects it to the nearest pitch frequency. I think if the tone is lower than the closest note, the \"missing\" wave cycles are synthesized, based on the input sound's wave shape, and then \"thrown into the mix\" to account for the time shift. If it's higher, then cycles are omitted.\n\nDue to how the technology works, short sounds like \"K\", \"P\" and similar percussive sounds are not auto-tuned because of a non-constant waveform (it evolves and changes over time); only constant sounds that could in theory go on forever (like a person who does not need to breathe, and has an infinite amount of air in his lungs, saying AAAAA...) are auto-tuned.\n\nAll pitches/tones has a set frequency, and in Western music it's always measured in 12th root factors starting at 440 Hz, which is a natural A (in the fourth octave). This \"table\" of known frequencies is used to shift sounds towards the closest pitch."
]
}
|
[] |
[] |
[
[]
] |
|
2xy8ul
|
Does the sun's parent star have a name?
|
We know that the sun was created in a molecular cloud. If I'm not mistaken, that type of cloud comes from an exploding star. I'm curious as to whether or not scientists have named that star. (and the cloud too.)
On a side note, how long did the cloud last? Does it still exist in some way? Do we know of any sibling suns that were created in the same place, and by the same star? If so, which ones?
I'm pretty curious about our solar system's origins but I wasn't able to find anything online, so I was hoping maybe reddit might know.
|
askscience
|
http://www.reddit.com/r/askscience/comments/2xy8ul/does_the_suns_parent_star_have_a_name/
|
{
"a_id": [
"cp6pe56"
],
"score": [
3
],
"text": [
"I'm only a major in astrophysics, so I don't yet have super advanced knowledge, but it's my understanding that only a portion of the cloud formed our solar system, meaning there are other bodies from the same cloud. It does not still exist, though it is entirely possible that a star created from it made another cloud and this cycle continued until today, meaning there would still be some of the original hydrogen currently in a different cloud.\n\nEdit: sorry for the accidental double post."
]
}
|
[] |
[] |
[
[]
] |
|
7qfcbl
|
Byzantine Army in the 15th Century
|
I realize that Byzantine is a wholly inaccurate term, but I’m using it in this post for simplicity.
So my question is, what was the army of the Eastern Romans (both standing - if there was such a thing - and levied - if levies still were widely used)? I’m curious about troop composition, equipment, and even doctrine and way of fighting. Were they like their Western European counterparts at this time and beginning to become professionalized, or were they still consisted of spear and shield wielding levies (an example question)?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/7qfcbl/byzantine_army_in_the_15th_century/
|
{
"a_id": [
"dspot23"
],
"score": [
6
],
"text": [
"One of the only good books on this subject is Mark C. Bartusis 'The Late Byzantine Army: Arms and Society, 1204-1453'. Even though the 15th century is more recent to us compared to the rest of Byzantine history, evidence of what their armies were actually like during this period is fairly fragmentary.\n\nHowever, from what we do know, late Byzantine armies were fairly unimpressive affairs. Unfortunately, in contrast with the well-trained, equipped and organised armies of the thematic system of the middle Byzantine period, the armies of the late Byzantine period were quite ad hoc. \n\nLate Byzantine rulers adopted the self-defeating attitude that Byzantines made better farmers than soldiers and so were reticent to pull them off the land. Obviously they still raised levies of militia when required for defence, however these were usually poorly trained, equipped and organised, relying on formidable Byzantine fortifications to hold out against the enemy until they withdrew. Late Byzantine rulers never invested the time, effort or money into developing and maintaining a quality army.\n\nOn the rare occassion that late Byzantine armies went on the offensive, foreign mercenaries (most often western Europeans, but sometimes Turks or others) were prefered. These generally performed better than native armies, although their loyalty was always dubious and they were quite expensive. Considering how poor and decentralised 15th century Byzantium was, only small contingents of foreign mercenaries could be afforded (although sometimes larger bands were hired and not paid, causing them to either desert or start pillaging Byzantine lands).\n\n"
]
}
|
[] |
[] |
[
[]
] |
|
3o009a
|
What kind of interactions happened between the underground hip-hop and punk scenes in 1970s NYC?
|
I'm not talking about things like Blondie's Rapture or 'World Destruction', or the Beastie Boys. I'm more curious about the rise of both musical cultures affected each other on a personal level, in the streets and venues in NYC. Was there any kind of significant crossover in fan bases? Memorable concerts with both kinds of music?
Side note: This 'Pop Music' topic is producing some really interesting stuff. I like.
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/3o009a/what_kind_of_interactions_happened_between_the/
|
{
"a_id": [
"cvt9jix"
],
"score": [
2
],
"text": [
"Just commenting to say I'm super interested in this question! I was pretty involved with the DIY punk and hardcore scene in my early 20s and I often thought that there were a lot of similarities between punk and hip-hop. Would love to explore this!"
]
}
|
[] |
[] |
[
[]
] |
|
3a97xl
|
Was there a concept of racial supremacy before the 1500s?
|
Or with the discovery of the new world came supremacy based on race?
The only thing i can think of is between local tribes.
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/3a97xl/was_there_a_concept_of_racial_supremacy_before/
|
{
"a_id": [
"csaka0d"
],
"score": [
8
],
"text": [
"Yes, very much so.\nWe can see the beginning of a proto-racist culture (as opposed to jingoism say between Sparta and Athens) in classical antiquity.\n\nThe idea of superior and inferior peoples is explored especially well by [this book](_URL_0_) by Benjamin Isaac. Check the first chapter out, most of it is available there.\n\nYou can see in some authors like Herodotus that the Greeks were already associating certain physical features with the regions in which they were found, and had ways to explain it.\n\nConsequently, they tried to associate personality traits in a similar way, with Aristotle famously arguing nomads were the \"idlest of peoples.\" \n\nThe way in which these traits were analyzed certainly led to a kind of proto-racism in which the notion of the superiority of certain peoples was being explored, and often advocated. Still, we must accept that this appears to be a view that is still establishing itself, and it relatively subtle and could well be scientific in its endeavours. Whether it carries the same kind of malice as, say, biological works on black people during the peak use of slavery in the US, is doubtful, though."
]
}
|
[] |
[] |
[
[
"https://books.google.co.uk/books/p/princeton?id=jfylyRawl8EC&printsec=frontcover&source=gbs_ViewAPI&hl=en&redir_esc=y#v=onepage&q&f=false"
]
] |
|
3xiqnh
|
why don't the swiss speak a single language?
|
Why would three small regions that speak totally different languages unify like that? I get why they don't have their own language, but it's kind of weird that three areas that don't even speak the same language could feel connected enough culturally to become a single country.
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/3xiqnh/eli5_why_dont_the_swiss_speak_a_single_language/
|
{
"a_id": [
"cy4zjug"
],
"score": [
3
],
"text": [
"They are remnants of the many, many independent states in that region of Europe in the middle ages, that were able to maintain their independence in the age of state-building because alpine warfare is no joke."
]
}
|
[] |
[] |
[
[]
] |
|
97ovx6
|
why can bodies last 8+ hours without peeing during the night, but that would be a huge challenge during the day?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/97ovx6/eli5_why_can_bodies_last_8_hours_without_peeing/
|
{
"a_id": [
"e49vd3y",
"e49vsu1"
],
"score": [
4,
3
],
"text": [
"It's not a huge challange when you're busy. I don't know how exactly, but human body can tell when it's not the right time to go to the restroom. During work, for example, or during sleep.\n\nI have no urge to pee when I work 12 hour shifts, so it's possible when you're busy enough.",
"It is my understanding that when one is about to sleep, a hormone is released that limits urine production.\n\nAlso. You may want to discuss this frequent urination with your medical professional. It CAN be a sign of diabetes."
]
}
|
[] |
[] |
[
[],
[]
] |
||
1p0uy9
|
Can astronomers see further back in time than Hubble eXtreme Deep Field?
|
none
|
askscience
|
http://www.reddit.com/r/askscience/comments/1p0uy9/can_astronomers_see_further_back_in_time_than/
|
{
"a_id": [
"ccxqgc9",
"ccxr2j4"
],
"score": [
3,
3
],
"text": [
"Yes. We can see back to the cosmic microwave background. That's about 380.000 years after the beginning of the big bang. There's an argument that you could look back even further by looking at the neutrinos from the early universe, but that's far beyond our technology",
"With galaxies, sometimes but the XDF is definitely the biggest sample of extremely-distant galaxies we have. Beyond that, we can see the [cosmic microwave background](_URL_2_), light which has been travelling nearly unimpeded since 380,000 years after the Big Bang. That's the earliest light we'll ever be able to see, because before then the Universe was opaque, as light would bounce around from atom to atom, never getting far before smacking into another one.\n\nHowever, we can probe deeper in time than that indirectly. The CMB, for example, contains information about the Universe at 380,000 years, and that in turn tells us about the tiny wiggles and lumps in the density of the cosmos. We believe those were created during a period of accelerated expansion called [inflation](_URL_1_) which took place a tiny fraction of a second into the history of the Universe. Using increasingly accurate CMB measurements, we've been able to put excellent constraints on the nature of physics during inflation, physics at energies far higher than we could ever dream of probing here on Earth.\n\nWe can also get a very good (less speculative) sense of what the Universe was like a few seconds to minutes after the Big Bang, because that was the era when the Universe had the right temperature to [produce light elements](_URL_0_) like helium and deuterium. By measuring the abundances of these elements, we can indirectly test the Universe at those very early times.\n\nFinally, in the future we may be able to \"see\" using radiation which isn't light, and which has been travelling freely for far longer than light. Two main candidates are neutrinos and gravitational waves. These would both give us a whole new eye onto the early Universe - gravitational waves especially - but the exact same reason that they're good probes (they don't interact much with matter) is the reason they're almost impossible to detect! So stay tuned on that."
]
}
|
[] |
[] |
[
[],
[
"http://en.wikipedia.org/wiki/Big_Bang_nucleosynthesis",
"http://en.wikipedia.org/wiki/Inflation_%28cosmology%29",
"http://en.wikipedia.org/wiki/CMB"
]
] |
|
3j6suv
|
What is the considered the most accurate drawing of Achilles' shield?
|
Not sure if this question belongs here or not, but I'm looking to find the most accurate picture or drawing of Achilles' shield as described in the Iliad.
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/3j6suv/what_is_the_considered_the_most_accurate_drawing/
|
{
"a_id": [
"cumwt47"
],
"score": [
7
],
"text": [
"There can be no question of accuracy, because it's a purely fictional object. That said, the description of the shield in the Iliad does adapt various late artistic motifs that started to come in ca. 700 BC or a bit later, so it's possible to at least visualize bits of it. It has a lot in common with the shield in the Hesiodic poem called the Shield, which is probably getting on for a century later than the Iliad, but the two descriptions taken together strongly imply a tradition of elaborate shield descriptions, with many shared motifs.\n\nBut don't think of accuracy. Don't even think of ways that the shield description could feasibly be realized at the time - because it couldn't. Think instead of potential ways for audiences of the time to *imagine* the various scenes describes.\n\nWith that in mind, [this schematic representation](_URL_0_) is an accurate rendering of what M. M. Willcock calls \"a possible distribution of the figures\" (*A Companion to the Iliad*, p. 210).\n\nIn terms of specifics, the depictions shown in [the Wikipedia article](_URL_2_) would not be potential ways for 7th century audiences to imagine the shield, since the styles draw on artistic conventions from centuries later. [This one](_URL_5_) is slightly less horrible, but still uses techniques from a good 200-300 years later than the Iliad. Out of the ones that turn up in a Google search, [this one](_URL_3_) is probably the least silly, but it's still *pretty* silly because actual Greek art from ca. 700 BC [looked more like this](_URL_1_) or [this.](_URL_4_)"
]
}
|
[] |
[] |
[
[
"http://www.mlahanas.de/Greeks/Mythology/Images/AchillesShD.gif",
"http://content.ngv.vic.gov.au/col-images/api/EPUB001301/1280",
"https://en.wikipedia.org/wiki/Shield_of_Achilles",
"http://www.mlahanas.de/Greeks/Mythology/AchillesShieldImage.html",
"https://upload.wikimedia.org/wikipedia/commons/7/77/Amphora_Athens_Louvre_A512.jpg",
"http://meieus.com/achillesshield/FullShieldMap.html"
]
] |
|
lkzx2
|
how does a quartz clock work? what the heck does a crystal have to do with keeping time? thanks in advance.
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/lkzx2/eli5_how_does_a_quartz_clock_work_what_the_heck/
|
{
"a_id": [
"c2tj4f5",
"c2tj4yj",
"c2tjbwf",
"c2tl60z",
"c2tj4f5",
"c2tj4yj",
"c2tjbwf",
"c2tl60z"
],
"score": [
17,
207,
4,
4,
17,
207,
4,
4
],
"text": [
"ELI5: Something really weird happens when you hook a piece of quartz up to a battery: it vibrates. If you know how fast it vibrates, you can use it to measure time. \n[ELI12](_URL_0_)",
"[Here you go](_URL_0_)",
"The Engineer Guy is a great guy and engineer.",
"A quartz watch works by hooking up a battery to a tiny piece of quartz in the shape of a fork. Doing this makes the quartz jump around because it's getting shocked by the battery.\n\nThe cool part is that the quartz moves around a very precise amount, so the only thing the circuits in the watch have to do is count how many times the quartz moves back and forth. If the quartz has moved back and forth 30,000 times then one second has gone by.",
"ELI5: Something really weird happens when you hook a piece of quartz up to a battery: it vibrates. If you know how fast it vibrates, you can use it to measure time. \n[ELI12](_URL_0_)",
"[Here you go](_URL_0_)",
"The Engineer Guy is a great guy and engineer.",
"A quartz watch works by hooking up a battery to a tiny piece of quartz in the shape of a fork. Doing this makes the quartz jump around because it's getting shocked by the battery.\n\nThe cool part is that the quartz moves around a very precise amount, so the only thing the circuits in the watch have to do is count how many times the quartz moves back and forth. If the quartz has moved back and forth 30,000 times then one second has gone by."
]
}
|
[] |
[] |
[
[
"http://www.physlink.com/education/askexperts/ae559.cfm"
],
[
"http://www.youtube.com/watch?v=1pM6uD8nePo"
],
[],
[],
[
"http://www.physlink.com/education/askexperts/ae559.cfm"
],
[
"http://www.youtube.com/watch?v=1pM6uD8nePo"
],
[],
[]
] |
||
fxowk7
|
when, where and why did the no-vax movement appear?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/fxowk7/eli5_when_where_and_why_did_the_novax_movement/
|
{
"a_id": [
"fmvmzs0"
],
"score": [
10
],
"text": [
"In 1998 a British Doctor, Andrew Wakefield, published a medical paper linking the MMR vaccine to Autism.\nHe did so because he wanted to make money selling the individual vaccines.\nThis was eventually found out and all the \"research\" he did was discredited but unfortunately it was out there and so the information spread and people became hostile to vaccines.\n\nHe's been completely revoked as a doctor but that doesn't stop him using the title when he attends events in the US where he speaks at anti vaccination talks and so on."
]
}
|
[] |
[] |
[
[]
] |
||
37bzvm
|
what is an analog computer (like the antikythera mechanism), and how does it work?
|
I read an article this morning on the Antikythera mechanism and I pretty much didn't understand a word of it. How did they make a "computer" in Ancient Greece? What is an "analog" computer anyway? What are they capable of doing?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/37bzvm/eli5_what_is_an_analog_computer_like_the/
|
{
"a_id": [
"crldlgk",
"crldyur"
],
"score": [
5,
2
],
"text": [
"Analog computers perform some (usually specialised) mathematical operations using wheels, cogs, levers, or slides.\n\nSome examples, in addition to the antikythera:\n[The Slide Rule](_URL_2_), used for finding approximations for certain mathematical operations;\n\n[The Curta Calculator](_URL_1_), capable of performing addition, subtraction, multiplication *and* certain types of division;\n\n[The Harmonic Analyser](_URL_0_), a mechanical computer that performs Fourier decomposition analysis on waveforms and can re-create waveforms from digital Fourier representations. (Every video this guy makes is superb, and worth watching).\n\nThose are some of the more general-purpose analog computers that have existed; some are incredibly specialised for their purposes (during WWII, for example, some bombers used specialised analog computers to calculate bomb drop timing.\n",
"Analog stuff works by having moving mechanical parts, rather than electronic wires, this restricts a lot their capacity, they get bulky and prone to break downs.\n\n They can perform basic math though, like the one that that french guy who made one to help his accounting father (sorry no link mobile)"
]
}
|
[] |
[] |
[
[
"http://www.youtube.com/watch?v=NAsM30MAHLg",
"http://en.wikipedia.org/wiki/Curta",
"http://en.wikipedia.org/wiki/Slide_rule"
],
[]
] |
|
16u2ku
|
What are the advantages of being "cold-blooded"?
|
And if being "warm-blooded" is the superior, how come animals have not all evolved with "warm-blood"?
|
askscience
|
http://www.reddit.com/r/askscience/comments/16u2ku/what_are_the_advantages_of_being_coldblooded/
|
{
"a_id": [
"c7zcyac",
"c7zczjo",
"c7zdnz8"
],
"score": [
7,
22,
2
],
"text": [
"Animals that are cold blooded tend to originate from an environment where the temperature doesn't change by much (e.g. oceans).\n\nIn this case it is meaningless and wasteful to put energy into maintaining heat levels, and so they don't. However when in an environment subject to varied temperatures this is life threatening. Hence why more or less all of the warm blooded animals you see are land-dwelling. So one is superior for low temperature changes (cold blooded) and one for high temperature changes (warm blooded) each has advantages so both have occurred.\n\nThis is partly exemplified by amphibians who are land dwelling but cold blooded. As a result they have to continuously return to an area of water to maintain the right body temperature, a process which is effortful but advantageous as it allows them to reap the benefits of both land and water environments.",
"It is far less energy-use intensive. the animal's metabolism is substantially more economical because they don't have to continually burn energy just to maintain homeostasis. If these animals exist in a region where temperatures stay at a fairly constant range, they don't have to waste energy maintaining that range themselves, like we as warm blooded mammals would have to do. \n\nAs a consequence, some cold-blooded animals can go months between feedings, whereas we have to eat much more frequently. This also means some environments will have a higher carrying capacity for cold blooded species than warm blooded (they need to consume less resources individually and thus a larger population can be sustained).",
"Also be aware that 'cold' vs 'warm' isn't what is up, the notation is much more specific, [see the wiki](_URL_0_)\n\nmain points\n > ectothermy, controlling body temperature through external means, such as by basking in the sun\npoikilothermy, the ability of an organism to function over a wide internal temperature range\nbradymetabolism, the ability to greatly alter metabolic rate in response to need; for example, animals that hibernate"
]
}
|
[] |
[] |
[
[],
[],
[
"http://en.wikipedia.org/wiki/Cold-blooded"
]
] |
|
wbu1g
|
my 10 year old nephew wants to know, where does sound go? does it just disappear?
|
Well, what happens to sound and does it continue traveling ?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/wbu1g/my_10_year_old_nephew_wants_to_know_where_does/
|
{
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"text": [
"Sound results from vibrations in the air, similar to ripples in still water if you drop a pebble. Eventually the sound just runs out of energy and can't overcome the resistance of the air, so it peters out into nothing.",
"It eventually dissipates into the environment as a tiny amount of heat.",
"Let's do this in true five year old fashion.\n\nThe air around us is made up of molecules and particles. These molecules and particles aren't too unlike rubber balls. If I were to throw a rubber ball, the movement I gave it - the energy - would cause it to go flying towards whatever is in its path. Sometimes it's more rubber balls, and sometimes it's into the wall or the floor. Think of sound as someone throwing a rubber ball in this case.\n\nIf the rubber ball that I threw goes into more rubber balls, each one that it hits takes some of the energy in my ball and moves along its own path. But this leaves my ball with less energy since the other ball took some. Each time one ball hits another, they split the energy up until each rubber ball has almost no energy. This sometimes seems like the energy is disappearing, but it's still there in each ball.\n\nThe balls can sometimes hit the floor or walls as well. If the wall is solid, the ball will bounce off and keep most of its energy. Think of throwing the rubber ball against wood or cement. It bounces back to you pretty easily, right? Some other materials act more like a sponge and steal the energy from the ball. If you throw a rubber ball against a foam wall it doesn't bounce as far back. These walls steal more energy from the ball.\n\nThis is what happens with sound. When sound is made, it's like someone throws these rubber balls. Louder sounds are like they're throwing more balls very very hard. Quieter sounds are like they're throwing fewer balls and not very hard. This energy they make with the sound doesn't disappear, it just gets spread out until we can't hear it anymore through the air and through the walls and floor.",
"Sound is energetic air movements. So, take for instance, your voice. When you speak, you use the energy within your body to push air out of your lungs, through your vibration vocal chords, and into the air. Now that it is in the air, that little sound you made has a lot of space to cover! So it spreads out in three dimensions away from your mouth-- Kind of like a balloon expanding. \n\nLet's take a minute to think about a balloon, as it paints a good (simple) mental picture for expanding sound waves. A balloon starts out as a semi-thick piece of rubber. Now you blow into it and it expands in every direction. Blow into it again and it expands more. But now, that thick rubber that we started out with it being stretched and becoming thinner! We're forcing the same amount of mass to occupy more space. This is why sound levels get weaker the farther you are from the source. What started as a tight ball of energy when it left your mouth has now ballooned to cover the space between its point of origin (you mouth) and the listeners ears. The amount of energy lost follows what is called the inverse square law. Which is a fancy way of saying that every time you double the distance between the sound source and the your ears, the sound pressure drops by half (for the sake of argument). \n\nNow what happens to the stuff that doesn't go in your ears? Why doesn't it go on forever? Couple of reasons. The first is that, if your outdoors, thanks to the inverse square law, the sound eventually gets soooo spead out that there is no more energy left to transmit the original sound. \n\nIf you're indoors, it's a little different. For the sake of analogy, you can think of sound kind of like a basket ball. What happens if you drop a ball from should height? It bounces a few times before coming to a stop, right? Now why doesn't it bounce forever? That's because each time the ball hits the ground, it loses some of its energy in the form of heat (which it gives to the ground), there is also resistance in the air that is constantly leeching energy from the ball's movement. Now this is the same thing of what happens in a room! Sound leaves your mouth, or a stereo, or whatever, collides with your wall, and looses some of its energy to the wall. Combine that with the inverse square law and you can see why things don't go on forever! They're always losing their initial energy to either the air, or obstacles in their way! Pretty neat! \n\n(My first Explain it like I'm five answer! Tried to actually imagine explaining it to a youngin', so a lot of stuff is left out, and some is fudged for the sake of example.)",
"imagine a gust of air hitting a piece of wood and bouncing back and the air slows down. thats basically what happens but slowly.",
"ELI5 style:\n\nFill a bathtub with a little water and make a small splash. The ripples are like sound waves. He'll see them bounce around and eventually disappear. This is what happens. The energy in the sound wave gets dissipated into heat, but I can't think of a good way to illustrate that.",
"Sound excites particles not actually moves them. Think of it as a pendulum that eventually slows down and stops. The longer it goes the weaker it gets. Therefor the sound energy just fades away.\n\nSo if you try yelling in space, you wouldn't be able to hear along with everyone else because there are no particles for sound to excite.",
"like ripples on a pond, they just spread out until they are no longer recognizable compared to the usual waves",
"This topic relates to the long misunderstood question. \"If a tree falls in the woods, and nothing is around to hear it, does it make a sound.\"\n\nShort answer - No.\n\nThe tree will make vibrations shoot everywhere around it, but sound only happens when those vibrations interact with an eardrum, and your brain interprets those vibrations as \"sound\". Similar to the double-slit experiment. ",
"Sound is a form of energy like heat and light, though it is very very weak in comparison. As a sound is produced, particles and molecules in the air are jostled around outwardly from the sound's source in all directions.\n\nDrop a rock in a pond and you'll see waves heading outwardly and subsequently diminishing. Sounds is not so different. When sound continues outwardly, it spreads, this causes it to get weaker for a number of reasons; \n1) some of the energy transforms into movement energy, such as when you yell loudly in a small space and feel the vibrations on the wall.\n2) when the sound waves move outwardly they spread widely, and the energy must also spread out, thereby growing weaker to cover more distance.\n3) The sound energy is absorbed by substances in the air or any softer materials in nature in the surrounding area, i.e. trees, or soft human materials like foam.",
"Sound isn't a 'thing', like a ball or a shoe; it's a kind of movement, like the circle your bike's wheel moves in when you pedal.\n\nIf you stop pedaling your bike, it'll coast for a little while, but eventually the wheel will stop turning. In the same way, if you stop making noise, the air will keep moving that way for a little while (much less than a second, unless it's a really loud sound that has the strength to travel a long way, so you probably won't notice it), but it'll eventually stop moving."
]
}
|
[] |
[] |
[
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[]
] |
|
2lgk3u
|
Was Nebuchadnezzar psychologically confused/schizophrenic?
|
I've heard sources where he was said to have voices speaking to him and somewhat insane, is there any truth to this?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/2lgk3u/was_nebuchadnezzar_psychologically/
|
{
"a_id": [
"clupk6v",
"clusqz3",
"cluzat8"
],
"score": [
2,
2,
2
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"text": [
"To my knowledge, the only source for this legend of Nebuchadnezzar as having a mental illness is the Bible, specifically [the book of Daniel, Chapter 5.](_URL_0_) I am not sure what modern historians think about using the Bible as a historical document, but I know I wouldn't use it to support claims made about a character depicted as an adversary of the Hebrew people.\n",
"[Did Nebuchadnezzar actually go insane and live in a cave like the bible said?](_URL_0_)",
"As the other posters here have noted, the Biblical references to Nebuchadnezzar's mental imbalance appear to be garbled references to the last Babylonian king Nabonidus; whether or not Nabonidus was actually imbalanced he was certainly somewhat of a religious eccentric or at least an innovator who was portrayed in a negative light by the Babylonian priesthood for his changes as is recorded in for example the Nabonidus Chronicle. In particular he was accused of sponsoring the cult of the moon god Sin at Ur and especially Harran at the expense of the traditional Babylonian cult of Marduk. But again this is as much a matter of the efforts of his political enemies to delegitimize him."
]
}
|
[] |
[] |
[
[
"https://www.biblegateway.com/passage/?search=Daniel+5&version=NIV"
],
[
"http://www.reddit.com/r/AskHistorians/comments/2jvxcc/did_nebuchadnezzar_actually_go_insane_and_live_in/"
],
[]
] |
|
8f40cw
|
What did the Han Dynasty know about Rome and Vice Versa?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/8f40cw/what_did_the_han_dynasty_know_about_rome_and_vice/
|
{
"a_id": [
"dy0f8nq"
],
"score": [
2
],
"text": [
"Asking questions again is fine. Mentioning previous answers is not intended to discourage discussion. Further questions, data, or debate are welcome. Especially here, where the FAQ is more general, talking about diffusion along the Silk Road as well as direct knowledge.\n\nThere's an FAQ section at _URL_0_ . In the app, the # anchor doesn't work, so you look for \"Rome and ancient China\" near the bottom of the page.\n\nThere are answers by /u/Tiako , /u/octaviusromulus , and /u/leprechauns_scrotum ."
]
}
|
[] |
[] |
[
[
"https://www.reddit.com/r/AskHistorians/wiki/antiquity#wiki_rome_and_ancient_china"
]
] |
||
brow6j
|
what is sensory overload?
|
ELI5 , Is it common?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/brow6j/eli5_what_is_sensory_overload/
|
{
"a_id": [
"eofengh",
"eofexzn"
],
"score": [
5,
2
],
"text": [
"Too much stuff for your senses to keep track of happening at once - a lot of stimulus can become disorienting.",
"My niece’s son has and from what I understand it occurs when one or more of the body's senses experiences over-stimulation from the environment. There are many environmental elements that affect an individual. Examples of these elements are urbanization, crowding, noise, mass media, technology, and the explosive growth of information.\n\nI think it’s actually on the autism spectrum and can be quite challenging to deal with."
]
}
|
[] |
[] |
[
[],
[]
] |
|
78lsjc
|
when you stop the flow of water at the end of the hose does it keep increasing in pressure or equal out?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/78lsjc/eli5_when_you_stop_the_flow_of_water_at_the_end/
|
{
"a_id": [
"douuavh",
"douuc1h",
"douuff3"
],
"score": [
3,
2,
2
],
"text": [
"If you stopped the flow of water but the pressure kept increasing, some failure point would eventually give and burst.\n\nGiven every time you shut off the water at a hose/sink/faucet there isn't some leak/burst, the pressure must hit a maximum and then equalize. ",
"If a hose is suddenly closed at one end, the pressure at the closed end will very quickly reach an equilibrium state: about the same pressure as elsewhere in the hose, give or take any effect of gravity. Once established, there is no more flow of water to cause further pressure changes from that.",
"You think the plumbing in your home forever keeps building pressure too? Why buy a pressure washer at all? Not trying to sound condescending, I think you need sleep bud. \n\nPressure is relatively constant. Blocking a hose is just like turning off the water valve. "
]
}
|
[] |
[] |
[
[],
[],
[]
] |
||
52z61u
|
When did it become common for civilizations to assist others after catastrophic events?
|
I assume this type of assistance predates the UN significantly, but how far back does it go? Would ancient cultures/tribes commonly assist neighbors if they had good relations? Or is this a more modern behavior?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/52z61u/when_did_it_become_common_for_civilizations_to/
|
{
"a_id": [
"d7onpc5"
],
"score": [
2
],
"text": [
"It has ancient antecedents. A particularly famous example occurred in 226 BC, when the city of Rhodes was struck by a tremendous earthquake which wrecked havoc in the city and toppled the famous Colossus of Rhodes. The historian Polybius provides a list of the kings and potentates who offered aid to the (independent) city.\n\n\n\"For Hiero and Gelo [rulers of Syracuse in Sicily] not only gave seventy-five silver talents, partly at once and the rest very shortly afterwards, to supply oil in the gymnasium, but dedicated silver cauldrons with their bases and a certain number of water-pitchers and in addition to this granted ten talents for sacrifices and ten more to qualify new men for citizenship, so as to bring the whole gift up to a hundred talents. They also relieved Rhodian ships trading to their ports from the payment of customs, and presented the city with fifty catapults three cubits long. And finally, after bestowing so many gifts, they erected, just as if they were still under an obligation, in the Deigma or Mart at Rhodes a group representing the People of Rhodes being crowned by the People of Syracuse. \n\nPtolemy also promised them three hundred talents of silver, a million artabae of corn, timber for the construction of ten quinqueremes and ten triremes, forty thousand cubits of squared deal planking, a thousand talents of coined bronze, three thousand talents of tow, three thousand pieces of sail-cloth, three thousand talents for the restoration of the Colossus, a hundred master builders and three hundred and fifty masons, and fourteen talents per annum for their pay, and besides all this, twelve thousand artabae of corn for the games and sacrifices and twenty thousand artabae to feed the crews of ten triremes. Most of these things and the third part of the money he gave them at once. Antigonus in like manner gave them ten thousand pieces of timber ranging from eight to sixteen cubits in length to be used as rafters, five thousand beams of seven cubits long, three thousand talents of silver, a thousand talents of pitch, a thousand amphorae of raw pitch and a hundred talents of silver, while Chryseis his wife gave them a hundred thousand medimni of corn and three thousand talents of lead. Seleucus, the father of Antiochus, besides exempting Rhodians trading to his dominions from custom duties, presented them with ten quinqueremes fully equipped, two hundred thousand medimni of corn, ten thousand cubits of timber and a thousand talents of hair and resin. Similar gifts were made by Prusias and Mithridates as well as by the other Asiatic princelets of the time, Lysanias, Olympichus,and Limnaeus. As for towns which contributed, each according to its means, it would be difficult to enumerate them.\" (Polyb. 5.88.5-90.2).\n\n\nAll of these monarchs were so interested in helping Rhodes because Rhodes was a hugely important city. In the normal course of events, she was wealthy enough to pick and choose her benefactors. But the earthquake left her in need of so much help that she could hardly refuse anyone, and so ended up owing favors to half the kings of the known world. \n\nThere are probably even older examples of this sort of disaster-relief, though none spring immediately to mind. It was not uncommon for wealthy foreigners to donate to a particularly renowned temple if it was struck down by earthquake or fire. Nor was it uncommon for rulers to grant remissions in taxes and tributes to cities struck by some disaster. But neither of these types of benefactions as closely mirrors modern international disaster relief as the Rhodian example."
]
}
|
[] |
[] |
[
[]
] |
|
391p83
|
why do they put punch holes in the side of kraft mac & cheese boxes?
|
You have to rip the box open to get to the cheese packet regardless, and if you try to pour it without opening the box first the big ass packet just blocks the hole anyway.
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/391p83/eli5_why_do_they_put_punch_holes_in_the_side_of/
|
{
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],
"score": [
2,
3
],
"text": [
"Apperently a hole at the side is more convenient? or less likely to make all the pasta fall out of the box in case of an accident? :s",
"The hole isn't for a spout, it's so you can more easily open the box. \nInsert thumb, then rip open top of box. \n\n_URL_0_"
]
}
|
[] |
[] |
[
[],
[
"http://imgur.com/BV7f3"
]
] |
|
4a9pp6
|
why do some police units, like the "gang unit" i saw last night at a concert dress in casual clothes other than their vests?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/4a9pp6/eli5_why_do_some_police_units_like_the_gang_unit/
|
{
"a_id": [
"d0yige9"
],
"score": [
5
],
"text": [
"Probably because they're undercover. Here in the UK that happens at concerts and shopping stores - they're more likely to catch people selling and using drugs if they aren't wearing a uniform."
]
}
|
[] |
[] |
[
[]
] |
||
5w3gge
|
what does it mean when mathematicians "find" a big number, like graham's number?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/5w3gge/eli5_what_does_it_mean_when_mathematicians_find_a/
|
{
"a_id": [
"de70d2j",
"de70x65"
],
"score": [
9,
3
],
"text": [
"It means they have proved that a particular number has some property.\n\nFor example, it's no secret that the following number exists...\n\n6353526374303929879127012501290127402919200192601923419028340912401927492180129801297012912012912261202912061\n\nWe don't need to go hunting for it. It's right there. However, is it prime? Is it a square? Is it a solution to < some famous equation > ?\n\nSome of these questions are hard or time consuming to answer. If I were to crunch a bunch of numbers and discover that the number above is prime, I could say that I \"found\" a prime number.",
"Suppose you left your diary on a table in Starbucks and you wanted to find how many people had read it before you realised. You might not be able to know the exact number (even though there is an exact solution) but you know it can't be more than, say, 100, as you weren't gone for long and the store isn't that popular. 100 probably isn't the actual solution but it's come about from the problem.\n\n\nThe same is true with 'finding' large numbers. For Graham's number, there was a problem in graph theory about how big a graph needed to be to have a certain property. We still don't know the exact answer, but it was proved that if the graph is at least as big as Graham's number it has the property (so Graham's number is an upper bound for the solution). It has since been shown that you can get away with using a much lower number instead, so Graham's number doesn't actually have that much use (only really in popularising mathematics). Other very large numbers come about in the same way, and usually they are quickly made redundant as mathematicians find much smaller upper bounds on the problem."
]
}
|
[] |
[] |
[
[],
[]
] |
||
mj3fm
|
the difference between art deco and art nouveau.
|
Ive always heard this two terms and I can't tell what's the difference between the two.
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/mj3fm/eli5_the_difference_between_art_deco_and_art/
|
{
"a_id": [
"c31brry",
"c31brry"
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2,
2
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"text": [
"They're related, and fairly similar, as art movements of the early 20th century and to a certain extent the difference is more gradual than anything else, but on the whole art nouveau is more on the decorative, ornamental side of things, where as art deco worked with cleaner, more stylized forms. That being said, I tend to think there's a large gray area of things that could be classified as part of either style.",
"They're related, and fairly similar, as art movements of the early 20th century and to a certain extent the difference is more gradual than anything else, but on the whole art nouveau is more on the decorative, ornamental side of things, where as art deco worked with cleaner, more stylized forms. That being said, I tend to think there's a large gray area of things that could be classified as part of either style."
]
}
|
[] |
[] |
[
[],
[]
] |
|
5t8o24
|
what happens to current debt during times of great inflation?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/5t8o24/eli5_what_happens_to_current_debt_during_times_of/
|
{
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"ddkxsxt",
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"text": [
"The value of that debt goes down.\nThat's why lenders factor inflation risk into their risk premium.",
"Suppose you took out a loan of $500 with the agreement that, one year later, you'd pay $1000. (obviously this is a terrible loan, just go with me) Over the course of that subsequent year, inflation was 10% (yikes!)\n\nYou still owe the $1000, but that money is only worth about $909 to the bank. That is unfortunate for the bank, but good for you. A low amount of steady inflation is generally considered a good thing for an economy, because it rewards the taking out of loans and spending of money today without making banks terrified to give out those loans. On the other hand, deflation (the opposite of inflation) is generally considered bad, because it makes people want to save their money rather than spend it.",
"You still owe a billion shekels in debt, but it become less valuable in terms of a stable currently like the dollar or the euro.\n\nCountries will often inflation devalue their currency as a way reduce a debt burden. That's part of the reason Greece was in so much trouble, being on the euro, this wasn't an option to them.\n\nThe prospect of debt being devalued is factored in to the terms of the debt. The bonds for most countries run pretty close to their inflation rates. If you are experiencing 15% inflation, do not expect to be able to borrow money at 5%."
]
}
|
[] |
[] |
[
[],
[],
[]
] |
||
5l3nev
|
Why does sublimation occur in some substances instead of melting?
|
What causes a material or element to skip a "stage" of matter and go immediately from a solid to a gaseous state?
|
askscience
|
https://www.reddit.com/r/askscience/comments/5l3nev/why_does_sublimation_occur_in_some_substances/
|
{
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"text": [
"The explanation is that solids can be in equilibrium with a gas just like liquids. In other words, atoms can (and do!) fly away from solid into a vapor and vice verse all the time. The atoms coming off from the solid create a finite [vapor pressure](_URL_0_) that depends on the specific material and its state. In some cases this vapor pressure is so low that you can safely treat an object (say a metal coin) as unchanging over years. On the other hand in other cases, say ice cubes in your fridge, the rate can be sufficiently high that you will see the cubes get smaller over the course of days. ",
"It's due to the pressure and temperature of the substance. Take a look at these phase diagrams:\n\n[Water](_URL_0_)\n\n[Carbon Dioxide](_URL_1_)\n\nOn the water diagram, look at the red line ~100kPa (1 atm). This is the typical pressure we find on Earth. Follow it along the x-axis (temperature) and you'll see the familiar solid until 0 C, liquid until 100 C. Now if the pressure was slightly under 1 kPa, you'll see we hit a triple point, this is the temperature/pressure at which water will exist in all three phases at the same time. Below that pressure, water sublimes, going directly from solid to gas. You'll also notice water has a bunch of different solid forms, this is due to rearrangements in the crystalline structure of ice at different pressures/temperature.\n\nOn the CO2 diagram, you'll see at 1 atm, it sublimes from solid to gas. We would need to put dry ice in a container pressurized above 5.11 atm to get liquid CO2.\n\nPhase diagrams are different for every single substance. Pressure and temperature, along with intermolecular forces and such, will determine what phase a substance will be, and whether it is able to sublime or will pass through a liquid phase.",
"Sublimation, and indeed any phase change, is determined by several intensive properties of the system, including temperature, pressure, and the molar density of the compound in each phase. The ultimate reason any phase change occurs is because the molecules can do work to move from one phase to another. This may seem like a somewhat cyclical definition, but in order to relate phase changes to thermodynamic quantities we need to start out simple.\n\nThe way we formally describe phase changes is through the quantity of chemical potential µ, AKA the amount of free energy per molecule. The formal definition of µ includes a term that is the \"standard\" free energy, a function of the temperature and pressure of the system, and a term that increases as density increases. \n\nNow free energy is the amount of energy available to do work, i.e. the total energy minus the random thermal energy. We can think of a phase change as the phenomenon where molecules move from one phase with energy G to another phase of energy G', which takes an amount of G' – G work to accomplish. Phase changes occur spontaneously if the molecule can move to a lower, more stable state. G is just the macroscopic analogue of µ, so this is analogous to saying that molecules will move from a higher µ to a lower µ'. This is much like how gasses move from higher pressure to lower pressure, however µ is even more general since it accounts for pressure, temperature, and density. IIRC Josiah Gibbs (the guy who formalized all of this science) originally referred to µ is \"pressure of mass action\" or something like that, which I think is a good intuitive description.\n\nSo now I think the crux of your question is how can it be that you can skip liquid when sublimation occurs. Don't you have to step up through each phase of matter sequentially as you gain chemical potential? \n\nThe answer is no. If you have enough chemical potential then the matter will simply not be able to condense into liquid and will fly out straight into the gas phase. Note that pretty much every substance has a certain ranges of temperature and pressure at which it can sublimate. Even water. The important thing is that these occur at relatively lower *pressures* compared to your normal solid-liquid phase change. If pressure is low, then molecules have to do less work to change from solid to gas because they have fewer other gas molecules to push out of the way. If they don't have to do much work to make the phase change, then basically as soon as they have enough thermal energy to do the work, they will escape the solid phase. This is an entropically-driven process that is exactly the same as a going from liquid to gas or solid to liquid. Sublimation is a specific special case where it just so happens that so little work needs to be done by the solid phase molecules that when they do the work, its enough to shoot right past the liquid phase and enter the gas phase. \n\nSo thats the \"what causes\" part of your question. The \"why\" part of this answer is quite complex. The why depends specifically and critically on the chemical properties of the molecules themselves. These properties make their contribution to chemical potential in the \"standard\" term that I was talking about earlier. You can always increase µ by increasing density, but some compounds just intrinsically have lower µ than others. A good example is water vs. CO2. Water can engage in lots of H bonding interactions, which effectively hold the molecules together more strongly. This means they have lower overall chemical potential than say CO2 molecules, which cannot engage in H bonding and therefore can move around and do work more easily. So now if we think about solid CO2 and solid H2O at 1 atm and 30ºC, you would expect the CO2 to sublimate and the water to melt. The liquid water can grab other H2O molecules more easily with those sticky H bonds, but the CO2 is relatively weak, and so those molecules just shoot straight out into the gas phase.\n\nThats kind of a hand-wavey intuitive answer, but you could also solve for the boundary mathematically by assuming µ(solid) = µ(liquid) and µ(solid) = µ(gas). Chemical potentials are equal at phase boundaries, so solving these equations is how people figure out how to draw the lines on phase diagrams. You would find that at 1 atm, there are no human-scale thermodynamic solutions in which you could make µ(ice) = µ(liquid) for CO2. Solutions will only appear in excess of 5.1 atm, because at these higher pressures the gas molecules can't just fly off into the atmosphere. The atmosphere itself does enough work on the evaporating molecules to trap them in a condensed phase, i.e. liquid.\n\nedit: words",
"Lots of answers here on the phase characteristics that substances show, but those just explain 'what' happens, not the intuition for the 'why' behind it, so lets take another approach.\n\nFor the purposes of building some insight, its actually better to think of matter as having only two distinct phases... bound and unbound. \n\nAn unconfined gas in in an unbound state, in that each gas molecule is essentially 'free' to move around without being 'bound' by other molecules.\n\nOn the other hand, solids and liquids are much better thought of as 'bound' states, where each molecule is held in a network of forces by other molecules around it that 'bind' it to them. \n\nWhen looked at this way, solids and liquids are very similar, with the only difference that solids are bound rigidly whereas liquids are bound and therfore can't escape the liquid body, but can move around internally. In fact, it is even more deeper... For instance, if you start heating a mtal rod, long before it gets to melting point, it will start becoming soft and flexible, almost to the extent of a wet noodle. So molecules there ARE indeed moving around internally, just with more difficulty. And indeed, if you think about it, even in cold hard solids, many are malleable that you can hammer them to change shapes etc. \n\nFurther, solids themselves often have various other phase transitions before the phase transition to liquid state which we call melting. So in fact, melting is NOT all that special from a solid's point of view. For instance, water ice itself has various phases that it transitions through in colder/denser environments before it gets to the liquid phase. And in all of these cases, the same fundamental phenomenon is happening internally, in that the molecules are reorgnizing into a configuration that is most energetically stable at that given temperature and pressure.\n\nNow regarding the 'bound' and 'unbound' stages, any molecule in a bound state that momentarily attains high enough energy will escape from the bound state to be unbound, and 'vaporize' into what we call gaseous stage. When this happens from liquids, we call it evaporation. When it happns from solids we call it sublimation, but it is the same phenomenon! Meaning that, there is always some 'vapor pressure' from these bound stages, whether it be some phase of solid, or liquid. \n\nSo looked at this way, the question is only about WHEN exactly the vapor pressure of a 'bound' stage reaches higher than the ambient pressure in that environment. If it is high enough when it is in a solid stage, then it will directly sublimate before/during any possible phase transition to liquid stage. \n\nFor instance, regular water ice has some 17 different solid phases, and for most of them, the only transition they can make is from one solid stage to another, but some 5 of those phases can transition into liquid phase, and some two of them can transition directly to gas phase, in some temperature and pressure conditions.\n\nCaveat : Finally, its worth noting that although we talked of 'gas' being in fully unbound stage, of course there is some small amount of inter-molecular attraction there too, and this will become more relevant as we pack more and more molecules in a confined space at high pressure. If you keep reducing the effective intermolecular distance more and more in this way, eventually the behavior will become similar to liquids because practially they are no longer 'unbound' and this state is what we'd call reaching a super-critical fluid, where liquids and gas behavior merges, and there is only 'bound' behavior left."
]
}
|
[] |
[] |
[
[
"https://en.wikipedia.org/wiki/Vapor_pressure"
],
[
"https://upload.wikimedia.org/wikipedia/commons/thumb/0/08/Phase_diagram_of_water.svg/700px-Phase_diagram_of_water.svg.png",
"https://stevengoddard.files.wordpress.com/2010/09/co2_phase_diagram.gif"
],
[],
[]
] |
|
hodzp
|
Are dental x-rays more dangerous than they're letting on? (Or Why is it that my vitals and reproductive organs need protection and my brain does not?)
|
I went to the dentist today. They tell me that they need some x-rays because it's been 6 months. First they pull out this big heavy led apron and cover up my vital organs and my crotch area. Then they point the gun directly at my brain, then they leave the room and from a safe distance zap the hell out of my brain.
There seems to be a disconnect here. They take precautions over my chest and pelvis but none for my brain. It makes me wonder if either the safety precautions are not really necessary or if they just decide that there's no good way to protect your brain when you need to x-ray teeth, so they just chalk it up to collateral damage. Or maybe the brain is not susceptible to whatever dangers they're trying to protect my heart/lungs/testicles from.
I hope this is a good question for askscience. I'm sure that if I searched the internet for "are dental xrays safe" I would find all sort of crackpot sites mixed in with whatever legitimate information (for or against).
I fully expect the consensus to be that dental xrays are low-strength highly focused and that the blankets are just done for good measure - and that the real question is whether dental xrays are necessary every 6 months. But I think maybe this is an educational opportunity. Besides the whole time I sat there with my mouth gaping open I thought about how I would ask this on askscience and it would be worth it if I got at least one good answer, so now I need to fulfill that promise to myself.
Thanks in advance!
|
askscience
|
http://www.reddit.com/r/askscience/comments/hodzp/are_dental_xrays_more_dangerous_than_theyre/
|
{
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"I took a ton of radiation safety classes because I operated/worked on nuclear reactors in the US Navy for several years. In those classes they told us that the human reproductive system is more sensitive to ionizing radiation than the rest of the body because those cells multiply more often than other cells. Brain cells, on the other hand, multiply less often than cells in other parts of the body, so they are at a lower risk of receiving radiation damage from xrays. As I understand it, cells that mutate from radiation damage and then multiply cause cancer. That's not to say bad things can't happen when your brain gets xrayed, just that they are less likely to happen than other parts of your body. Hope that's helpful. The other answers are also right but I thought this was a simpler explanation.",
"Well, ideally you would be covered in those protective lead clothes except for the specific area being x-rayed. Practically, however, it would be rather costly and time consuming to find the correct helmet for each patient, so they cover what is easy to cover. And then you have to worry about the patient's ability to keep their head still with added weight.\n\nYou shouldn't worry about it too much. X-rays in those very low doses won't harm you significantly. The detrimental effect of the x-ray will be countered by the benefit of the information gained from the x-ray. The reason the doctor, nurse, dentist, or assistant steps out of the room to start the x-ray is because they are performing these every day, and the radiation would add up over time for them.\n\nI can't speak to the frequency with which you should get x-rays of your teeth, you'd have to discuss that with your dentist.",
" > It makes me wonder if either the safety precautions are not really necessary or if they just decide that there's no good way to protect your brain when you need to x-ray teeth, so they just chalk it up to collateral damage. \n\nBoth. There's no real way to shield your brain while passing xrays through your jaw, but the exposure is pretty minimal. According to Wikipedia:\n\n\n > The dosage of X-ray radiation received by a dental patient is typically small (around 0.005 mSv), equivalent to a few days' worth of background environmental radiation exposure, or similar to the dose received during a cross-country airplane flight \n\nThe reason that the dentist leaves the room is that they give multiple dental x-rays every day, and that adds up pretty quickly, so they have to limit their exposure as much as possible.\n\n**Edit:** I'm not an expert. I had both AskScience and AskReddit open, and thought I was in the latter. However, I still believe my response is accurate, if perhaps not complete.",
"[Wikipedia](_URL_0_) may have your answer. It appears to be a precaution more than a requirement.",
"Ionizing radiation is believed to be inherently dangerous even in low doses at a linear rate compared to the dose. (At very low levels we don't really know if its still dangerous, but the most straightforward assumption is that it is. Most of our understanding of the dangers of radiation is from studying exposure to high doses; e.g., Hiroshima/Nagasaki. Its much more difficult to find the much smaller expected effect). \n\nThe average American gets exposed to about ~350 mrem of exposure to radiation in a year from natural sources (e.g., breathing radon gas coming up from decaying uranium in the earth, exposure to UV sunlight, cosmic rays, airplane flights (less protective atmosphere)). A set of dental x-ray is typically under 5 mrem. Now if your normal chance of getting cancer in a year due to ionizing radiation with 350 mrem may be something like 1 in 10000 (all cancers are not necessarily linked to ionizing radiation; e.g., genetics, exposure to toxic chemicals, viruses, etc also increase cancer risk). The linear models would have you that you will increase your risk, e.g., dental x-rays increase your chances from 1 in 10000 to 1.01 in 10000 for a given year (1 in 10000 was made up; but the percent increase should be about 1% from a single set of dental x-rays). So its just precautionary to reduce the dose as much as reasonable possible, especially to reproductive regions as they potentially grow rapidly and are particularly susceptible to mutations.\n\nThere has been talk about some danger from the newer [tooth CTs](_URL_0_) that some dentists have been buying which have considerably higher doses (instead of 2 mrem; it may give you ~200 mrem). But generate impressive looking 3-D models of teeth that wow patients into thinking their dentist/orthodontist is high tech.",
"I made a post a couple months ago about the general effects of radiation on your body [here](_URL_0_), which you may find useful. The context was the March earthquake in Japan and the ensuing nuclear concerns, but this may be a good place for you to get an idea about how dangerous radiation sources are.\n\nI would agree with everything you said in the original post--the machines are low power and highly focused--but since I don't have any experience in dentistry, I can't say how often you *should* be getting these x-rays. Since you're only going into the dentist every 6 months anyway, it seems reasonable to me to submit to one or two x-rays a year. The bonus for your dentist is that x-ray is an excellent diagnostic tool with which they may identify any problems below the gum line.\n\nAnyway, although the beams are highly focused, it's still very difficult to expose *only* the teeth; in other words, there is always some radiation leakage. As mentioned in my earlier post, different tissues absorb radiation differently, which leads to many different outcomes. The dentist will shield your torso because it's easily done and helps ensure you are maximally protected. On the other hand, the reason why your brain is left \"unprotected\" is probably because (1) there aren't any comfortable solutions to shield your head from dental x-rays and (2) you already have a hard, calcium wall (your skull) which probably already impedes the advance of ionizing radiation. (However, I will concede that this final point depends on the type of radiation and associated energy levels.)\n\nIn the end, I wouldn't worry about it."
]
}
|
[] |
[] |
[
[],
[],
[],
[
"http://en.wikipedia.org/wiki/X-ray#Health_risks"
],
[
"http://www.nytimes.com/2010/11/23/us/23scan.html"
],
[
"http://www.reddit.com/r/askscience/comments/g312j/japanese_are_being_advised_to_close_doors_and/c1kl2s8"
]
] |
|
1hwvmr
|
Why do humans see in the "visible" spectrum of light? Why not a higher, lower, larger or smaller spectrum?
|
askscience
|
http://www.reddit.com/r/askscience/comments/1hwvmr/why_do_humans_see_in_the_visible_spectrum_of/
|
{
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"text": [
"A couple of reasons.\n\nFirstly, the atmosphere isn't actually totally transparent. It blocks some wavelengths more than others. There's a couple of nice big transparent \"windows\", and these are radio waves and visual light. So if you want to see a large distance, you want to choose one of these. (This is why x-ray and gamma-ray telescopes are in space, while we have big radio and optical telescopes on the ground).\n\nSecondly, you need light that will nicely interact with molecules and cause chemical/electrical reactions, otherwise a chemistry-based lifeform won't be able to detect the light. Visual light does this too. That's why you likely won't ever find a life-form that can see radio or gamma waves.",
"You can see [here](_URL_0_[1].png) the peak optical intensity of sunlight occurs at ~400-700nm so if you are going to evolve to see really well during the day this is the range you want to be working with. \n\nLonger wave IR is hard to detect without the sensing organ being very sensitive to low energy photons, which in turn would be excited by higher energy visible photons. You can actually sense long wave IR rather well by your skin you just dont have good resolution. ",
"I'll quote from [_URL_1_](_URL_0_) (emphasis mine if you feel like skimming)...\n\n > As the [diagrams](http://www._URL_1_/HP/WCL/IMG/lumbias.gif) at right show, **there is an especially close correspondence between the human visual span and the wavelengths of minimum water absorptance**, including liquid and water vapor — and the large bead of mostly water, the vitreous humor, that inflates the eye and sits between the pupil and retina. Human light sensitivity is located on the \"uphill\" side of this lowest point, away from UV radiation and toward the infrared side of the light window. **All vertebrates have inherited visual pigments that evolved in fishes, which may explain why our pigments are tuned to these wavelengths**. \n\n > **A second possible constraint is the range of chemical variation in photopigments**, for example as expressed in all known animal photopigments. The [figure](http://www._URL_1_/HP/WCL/IMG/pigspan.gif) below shows the wavelengths of maximum sensitivity for the four human photopigments in relation to animal photopigments with the lowest and highest peak sensitivities — from 350 nm (in some birds and insects) to 630 nm (in some fish). This puts the outer boundaries of animal light sensitivity between 300 nm to 800 nm. **Human vision is in the middle of the range that other animals have found useful**. \n\n > A third constraint has to do with the span of visual pigment sensitivity, because **the sensitivity curves must overlap to create the \"triangulation\" of color**. For Dartnall's standard shape at 50% absorptance, this implies a spacing (peak to peak) of roughly 100 nm. If we include the \"tail\" responses at either end of the spectrum, **a three cone system could cover a wavelength span of about 400 nm**.\n\n > The fourth and last constraint is more subtle but equally important: **avoiding useless or harmful radiation**.\n\n > **At wavelengths below 500 nm (near UV), electromagnetic energy becomes potent enough to destroy photopigment molecules and, within a decade or so, to yellow the eye's lens**. Many birds and insects have receptors sensitive to UV wavelengths, but these animals have relatively short life spans and die before UV damage becomes significant. Large mammals, in contrast, live longer and accumulate a greater exposure to UV radiation, so their eyes must adapt to filter out or compensate for the damaging effects of UV light. In humans these adaptations include the continual regeneration of receptor cells and the prereceptoral filtering of UV light by the lens and macular pigment.\n\n > **At the other extreme, wavelengths above 800 nm are heat, which is less informative about daylight object attributes: it is dimmer than shorter wavelengths, is heavily absorbed by liquid water or water vapor, and lacks the nuanced spectral variations that can be interpreted as color**. In mammals, the visual system's heat sensitivity would have to be shielded from the animal's own body heat at wavelengths longer than 1400 nm, and the very long photopigment molecules (or artificial dyes) necessary to absorb radiation in wavelengths between 800 nm to 1400 nm are known to oxidize or decompose readily. These complications make long wavelength energy more trouble than it is worth.\n\n > On balance, then, it seems that animal vision is limited at the wavelength extremes as much as it is anchored by a radiance peak or an inherited range of photopigment possibilities. ",
"The three biggest reasons are: 1: The sun's peak emissions are in the optical range. 2: They're relatively easy to detect. And 3: They penetrate through the atmosphere extremely well."
]
}
|
[] |
[] |
[
[],
[
"http://www.apptechy.com/OpticalMeasure/Solar_Spectrum"
],
[
"http://www.handprint.com/HP/WCL/color1.html#monochromat",
"handprint.com",
"http://www.handprint.com/HP/WCL/IMG/pigspan.gif",
"http://www.handprint.com/HP/WCL/IMG/lumbias.gif"
],
[]
] |
||
2p7ea1
|
what are the steps taken to ensure that mold doesn't grow in a bathroom?
|
I understand some people may have mold growing in their bathrooms but I don't have any in my bathroom and I shower everyday which causes a lot of water vapor in the air. Why haven't I seen mold growing from all that vapor??
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/2p7ea1/eli5_what_are_the_steps_taken_to_ensure_that_mold/
|
{
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"cmu4t2j"
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2
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"text": [
"It can depend a lot on your climate, and how often the bathroom is cleaned. If you clean it often, or had very good grout put in to start with, then that makes it harder for mould to grow.\n\nVentilation is also a factor, if you have an extractor fan or leave a skylight open a bit (we do where I live), then that gets the moisture out fairly fast, but if your shower is in a small room, that has very little airflow and has the door shut most of the time, then the increased amount of water vapour that gets trapped will make mould growth more likely."
]
}
|
[] |
[] |
[
[]
] |
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