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9snnjc
Mesoamerican societies of the 9th century
Hello. I'm writing a short story about the **brazilian wizarding school from Harry Potter**, and I'm researching the inhabitants and cultures of its time of foundation. **The school is believed to have been founded in the 9th century**, and is historically known to accept students from all of South America, being c...
AskHistorians
https://www.reddit.com/r/AskHistorians/comments/9snnjc/mesoamerican_societies_of_the_9th_century/
{ "a_id": [ "e8q0z6d" ], "score": [ 2 ], "text": [ "Hi there - we're happy to approve your question related to your novel, and we are happy for people to answer. However, we should warn you that many flairs have become reluctant to answer questions for aspiring novelists, based on past experience...
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[ [] ]
1z7hux
As species evolve, where does extra genetic material come from?
I know as species evolve, they gain and lose genetic material. Where does it come from when it is gained?
askscience
http://www.reddit.com/r/askscience/comments/1z7hux/as_species_evolve_where_does_extra_genetic/
{ "a_id": [ "cfrfavp" ], "score": [ 3 ], "text": [ "I will give a preliminary answer, but i'm sure a good biochemist can go into more detail. There are a few sources of this DNA:\n\n[Transposons (Transposable elements)](_URL_2_) can \"reshuffle\" genes within the host organism, kind of like cut/co...
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[ [ "http://www.ncbi.nlm.nih.gov/pubmed/20728190", "http://en.wikipedia.org/wiki/Horizontal_gene_transfer", "http://en.wikipedia.org/wiki/Transposon" ] ]
1fn8p9
The unit of meter and the speed of light
It always fascinated me that, a unit of measurement(the meter in this case) that is derived from the geographic properties of our planet(distance between the north pole and equator) corresponds to the distance a photon covers in a vacuum in a second, so ''roundly''.So it's not,say 123.456km/s but it's 299.297km/s which...
askscience
http://www.reddit.com/r/askscience/comments/1fn8p9/the_unit_of_meter_and_the_speed_of_light/
{ "a_id": [ "cabw1qv", "cabw6q1", "cabw85g", "cabw86b", "cabwif9" ], "score": [ 2, 3, 6, 2, 8 ], "text": [ "There is no connection between the geographical definition of the metre and the modern-day figure's \"roundness\", no. In fact, \"roundness\" itself is not re...
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[ [], [], [], [], [] ]
11y88y
What exactly did the Ancient traders trade?
AskHistorians
http://www.reddit.com/r/AskHistorians/comments/11y88y/what_exactly_did_the_ancient_traders_trade/
{ "a_id": [ "c6qk3wb", "c6qkc86", "c6qky0d", "c6ql9zm", "c6qnb3d", "c6qq49g", "c6qq4yp", "c6qqyee" ], "score": [ 2, 29, 3, 11, 12, 2, 6, 3 ], "text": [ "Could you be a little more specific? The answer to this question is going to depend heavi...
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[ [], [ "http://en.wikipedia.org/wiki/Uluburun_shipwreck" ], [], [], [ "http://phoenicia.org/imgs/testavet.gif", "http://phoenicia.org/imgs/daggar.gif", "http://phoenicia.org/imgs/vase1.jpg" ], [], [], [] ]
2syjyq
why do senior citizens get discounts, and poorer people don't?
explainlikeimfive
http://www.reddit.com/r/explainlikeimfive/comments/2syjyq/eli5why_do_senior_citizens_get_discounts_and/
{ "a_id": [ "cnu1hs7", "cnu1iqm", "cnu1shz", "cnu2p3w" ], "score": [ 5, 3, 10, 3 ], "text": [ "There are plenty of programs and benefits for poor people, the problem is proving you're poor (it's much easier to prove you're a senior, just show your driver's license). For ex...
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[ [], [], [], [] ]
6aklnj
why is/has russia historically always been a poor country despite it's massive geographical and strategic location?
[deleted]
explainlikeimfive
https://www.reddit.com/r/explainlikeimfive/comments/6aklnj/eli5_why_ishas_russia_historically_always_been_a/
{ "a_id": [ "dhf8fat", "dhfbx0i", "dhffylp", "dhfhdvk" ], "score": [ 9, 3, 15, 3 ], "text": [ "it all comes down to size.\nRussia has a huge population but actualy a realy small population per square km. Same goes for natural rescourses and even for acces points. Russia is...
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[ [], [], [], [] ]
3173b4
why are dogs attracted to whistling?
explainlikeimfive
http://www.reddit.com/r/explainlikeimfive/comments/3173b4/eli5_why_are_dogs_attracted_to_whistling/
{ "a_id": [ "cpz4jjb" ], "score": [ 2 ], "text": [ "They are not attracted to whistling as much as they are trained, instructionaly or instinctively, to respond to whistling." ] }
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[ [] ]
1spf3u
why are works of art like the scream and the mona lisa considered masterpieces?
explainlikeimfive
http://www.reddit.com/r/explainlikeimfive/comments/1spf3u/eli5_why_are_works_of_art_like_the_scream_and_the/
{ "a_id": [ "cdzw1u4" ], "score": [ 3 ], "text": [ "If you search on the term \"Mona\" in this sub, you'll find a heck of a lot of answers for that part of your question.\n\nThe cliffnotes version for the Mona Lisa is that it's not *that* technically amazing, it's a fantastically well done piece b...
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2cgfcd
how does the cream on a ice cream cake not get frozen?
So I'm eating a Carvel Ice Cream right now and I was wondering......How is it that the whipped cream on the top of the cake stays warm even after being in the freezer while the rest of the cake is still frozen??
explainlikeimfive
http://www.reddit.com/r/explainlikeimfive/comments/2cgfcd/eli5how_does_the_cream_on_a_ice_cream_cake_not/
{ "a_id": [ "cjf7axm", "cjf7gfm", "cjfjhxn" ], "score": [ 4, 2, 2 ], "text": [ "Well, whipped cream has a lot of air in it. I mean, really, a *lot* of air. Air is a pretty bad conductor of heat. Bad conductor means that it won't change temperatures very easily.", "Probably beca...
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[ [], [], [] ]
8oivgf
why do passports expire?
It makes sense for things like a driver's license, where age/vision/etc could impact future driving. Why don't governments just make passports valid for a lifetime?
explainlikeimfive
https://www.reddit.com/r/explainlikeimfive/comments/8oivgf/eli5_why_do_passports_expire/
{ "a_id": [ "e03pe0o", "e03pmab", "e03styj", "e0459as" ], "score": [ 13, 16, 3, 2 ], "text": [ "I got my first passport at 17. I am now 49.\n\nIf I showed off that 1986 passport to a border/immigration official, he'd have a hard time reconciling the photo with the guy stand...
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[ [], [], [], [] ]
11dlw1
Why are there so many differences (racially, linguistically, etc.) between India and China?
For countries that are so close to each other it seems odd that the racial differences are so pronounced. Does it have to do with the mountains dividing them?
askscience
http://www.reddit.com/r/askscience/comments/11dlw1/why_are_there_so_many_differences_racially/
{ "a_id": [ "c6lirwe" ], "score": [ 5 ], "text": [ "The Himalaya Mountains separate India from China. That mountain range is *enormous*. It is easier to cross oceans than the Himalayas." ] }
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[ [] ]
4zdvca
how are people who live paycheck to paycheck able to budget their money so pefectly to end up with zero each week?
explainlikeimfive
https://www.reddit.com/r/explainlikeimfive/comments/4zdvca/eli5_how_are_people_who_live_paycheck_to_paycheck/
{ "a_id": [ "d6uxxqh" ], "score": [ 2 ], "text": [ "Honestly when I was paycheck to paycheck I just made sure to stock up food, get a bus pass, and then just spend till it was gone." ] }
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6mhvur
why do many websites make apps for themselves instead of updating their site for mobile users?
I was watching a [video](_URL_0_) by one of my favorite people to read and watch online, and this video (like most of his) made me think. Why do websites make a formatted mobile version of their site and make an app? Using Reddit as an example; how come the app misses features that the mobile browser version has, yet...
explainlikeimfive
https://www.reddit.com/r/explainlikeimfive/comments/6mhvur/eli5_why_do_many_websites_make_apps_for/
{ "a_id": [ "dk1rint" ], "score": [ 4 ], "text": [ "Apps have the potential to give much more information about you to the company than a website does." ] }
[]
[ "https://youtu.be/MTOa2Imauqk" ]
[ [] ]
2idyho
how much louder does a sound have to be to notice it got louder?
Does it depend on frequency?
explainlikeimfive
http://www.reddit.com/r/explainlikeimfive/comments/2idyho/eli5_how_much_louder_does_a_sound_have_to_be_to/
{ "a_id": [ "cl1c0e7" ], "score": [ 2 ], "text": [ "Each increase in sound is judged relative to the previous amount of sound. In general, the more sound already present, the more volume has to increase in order for the human perceptual system to notice the change. This generalization isn't always...
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[ [ "http://en.wikipedia.org/wiki/Weber%E2%80%93Fechner_law#The_case_of_sound", "Wikipedia.org" ] ]
5xm7pz
Was there a large risk that the Enola Gay could have been shot down prior to dropping the atomic bomb? What would have happened had it been shot down?
I was reading somewhere recently that in order to carry the bomb, the Enola Gay had had its turrets and additional armor removed. We're the allied commanders not worried about Japanese anti air resistance? (I can understand the removal of the turrets since Japanese air power at this point had been pretty crippled.)
AskHistorians
https://www.reddit.com/r/AskHistorians/comments/5xm7pz/was_there_a_large_risk_that_the_enola_gay_could/
{ "a_id": [ "dejg943" ], "score": [ 52 ], "text": [ "The Silverplate B-29s did have their turrets removed, save for the twin .50-caliber in the tail turret, but this was becoming par for the course for many B-29s operating in the Pacific. The switch from high-altitude day bombing to low/medium-alt...
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a4a46c
When the Russian Revolution happened, how many working-class Russians actually knew what Communism is?
The Russian Empire was very vast with many small populations hundreds of kilometres away from each-other. It seems inconceivable to me that most even really understood the nuances of their current events. When I say "Russian", I of course don't just mean ethnic Russians but also the many different ethnicities within t...
AskHistorians
https://www.reddit.com/r/AskHistorians/comments/a4a46c/when_the_russian_revolution_happened_how_many/
{ "a_id": [ "ebdyrup" ], "score": [ 15 ], "text": [ "By working class do you mean urban blue collar workers? Or does this term also include the rural peasants?" ] }
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[ [] ]
3fjrf3
Why didn't Lord Palmerston use the Trent Affair as a casus belli for siding with the Confederacy in the US civil war?
Prime Minister Palmerston was pro-confederate, nationalist, and had made his career as foreign minister by military intervention in similar circumstances (the Don Pacifico affair). What were the political checks and balances in the UK parliament that stopped Palmerston from intervening in the US civil war?
AskHistorians
http://www.reddit.com/r/AskHistorians/comments/3fjrf3/why_didnt_lord_palmerston_use_the_trent_affair_as/
{ "a_id": [ "ctpfr0d" ], "score": [ 27 ], "text": [ "The road to war was not as well paved with Palmerston as you imply.\n\nAt the outset of the Civil War, British subjects invested a lot of their savings in American securities, around 27% of the exports of Great Britain went to the United States,...
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2aigi0
how does wireless communication keep getting faster if radio waves already travel at the speed of light?
explainlikeimfive
http://www.reddit.com/r/explainlikeimfive/comments/2aigi0/eli5_how_does_wireless_communication_keep_getting/
{ "a_id": [ "civfle1" ], "score": [ 2 ], "text": [ "Sound generally travels at the same speed, but you can get better at talking faster and understanding faster speech. Same thing, basically. The signal takes the same time to get there but contains more data per second." ] }
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6swvwb
if a nuclear missile is shot down from the sky, say several miles above a large city, what would happen to the city below?
explainlikeimfive
https://www.reddit.com/r/explainlikeimfive/comments/6swvwb/eli5_if_a_nuclear_missile_is_shot_down_from_the/
{ "a_id": [ "dlg58el", "dlg5ces", "dlg6md3", "dlg6t5z" ], "score": [ 4, 12, 2, 4 ], "text": [ "Missile parts would fall from the sky\n\nThere would be no nuclear detonation, they're wayyyy harder to detonate than a normal bomb because if everything doesn't go perfectly you ...
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[ [], [], [ "http://mentalfloss.com/article/17483/8-nuclear-weapons-us-has-lost" ], [] ]
3g490g
It seems that most earth-like expo-planets are bigger than the earth. Who is this so?
*Exo-planets
askscience
http://www.reddit.com/r/askscience/comments/3g490g/it_seems_that_most_earthlike_expoplanets_are/
{ "a_id": [ "ctvnozn" ], "score": [ 7 ], "text": [ "Because of the way we look for them. There are two methods of findibg exoplanets. You can look of their shadow, or you can look for their gravitational effect on their star. If a star dims periodically and by a regular ammount it is probably due ...
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[ [] ]
x58xm
Suggestions for books on Lithuania?
I'm looking especially at Lithuania during the late Tsarist period (past 1900), and during the first period of independence in the interwar period. Any suggestions would be really appreciated. Alternatively, any books that have to do with the Baltics in general would be well-received.
AskHistorians
http://www.reddit.com/r/AskHistorians/comments/x58xm/suggestions_for_books_on_lithuania/
{ "a_id": [ "c5jbxk0" ], "score": [ 2 ], "text": [ "I know this may sound unhelpful, but I'm curious why the era of choice if the 20th century. To me, the Northern Crusades were far more interesting, and as a direct result of the Teutonic marches, one could argue that the concept of Lithuanian ide...
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d8sapq
why does salt so significantly change the flavor of tomatoes?
explainlikeimfive
https://www.reddit.com/r/explainlikeimfive/comments/d8sapq/eli5_why_does_salt_so_significantly_change_the/
{ "a_id": [ "f1cbzxh" ], "score": [ 12 ], "text": [ "Salt does two things, it increases salivation which helps deliver the flavor of tomatoes to your taste buds, and it supresses the bitterness receptors in your mouth, which helps tomatoes taste sweeter than they normally are." ] }
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3rk7h9
How do we find (-1)^pi? More generally, how do we find an irrational power of a negative number?
askscience
https://www.reddit.com/r/askscience/comments/3rk7h9/how_do_we_find_1pi_more_generally_how_do_we_find/
{ "a_id": [ "cwoubnv" ], "score": [ 17 ], "text": [ "Given two complex numbers *z* and *w*, z^(w) is generally defined as\n\n > z^(w) = e^(w log(z)^)\n\nwhere log(z) is a logarithm of *z*. I say ***a*** logarithm because the logarithm is not unique. (All logarithms differ by an integer multiple o...
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5o1d5s
Did the Soviet Union ever participate in UN Peacekeeping?
Basically what the title says. I've been trying to look through Wikipedia and other sources but to date have found no examples of USSR involvement in UN Peacekeeping efforts, either by supplying troops or material. If this is correct, any idea why they didn't? I would assume a major power with worldwide aspirations ...
AskHistorians
https://www.reddit.com/r/AskHistorians/comments/5o1d5s/did_the_soviet_union_ever_participate_in_un/
{ "a_id": [ "dcg007p" ], "score": [ 19 ], "text": [ "They never sent troops or police or materials. They did, occasionally, send observers, most notably in the 1973 Yom Kippur war, as part of the UNEF II mission. Their first involvement with actual troops and police was after the breakup of the US...
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[ [] ]
4ux5mb
even when there are clear blue skies all day, why does night time almost always bring clouds?
explainlikeimfive
https://www.reddit.com/r/explainlikeimfive/comments/4ux5mb/eli5even_when_there_are_clear_blue_skies_all_day/
{ "a_id": [ "d5tzrc3" ], "score": [ 3 ], "text": [ "It gets colder at night. Colder air can't hold as much water, and the water cools too, so it condenses into clouds. Clouds are liquid water, not gas. That water is still in the air during the day, it's just invisible vapor." ] }
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6xtvo4
Medieval Period quesion.
I'm looking for a factually accurate book(s) about life during the lower middle ages. Especially "peasant" life. There are so many myths and inaccuracies out there, I don't know where to start.
AskHistorians
https://www.reddit.com/r/AskHistorians/comments/6xtvo4/medieval_period_quesion/
{ "a_id": [ "dmj7zkj" ], "score": [ 3 ], "text": [ "When you say \"lower Middle Ages,\" do you mean in the French sense of *bas moyen age*, ~1000-1500? (English would usually say \"early\" and \"later\" rather than high and low).\n\nIf so, you might be interested in:\n\n* Ian Mortimer, *The Time T...
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[ [] ]
1um3sv
so what was b:\ drive? why isn't a:\ drive the primary and how did c:\ become king?
explainlikeimfive
http://www.reddit.com/r/explainlikeimfive/comments/1um3sv/so_what_was_b_drive_why_isnt_a_drive_the_primary/
{ "a_id": [ "cejgpii", "cejgpsn", "cejgqn1", "cejgsn9", "cejizpd", "cejjqg9", "cejkn16", "cejlt5l", "cejlys8", "cejmah0", "cejmbou", "cejqvd5", "cejvraz" ], "score": [ 13, 135, 36, 2, 3, 12, 2, 3, 9, 2, 2, 7, 2...
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[]
[ [], [], [], [], [], [ "http://i.imgur.com/4CG9Dyx.jpg" ], [], [], [], [], [], [], [] ]
4vzqv6
Do we lose our ability to remember dreams as we get older? If so, why?
askscience
https://www.reddit.com/r/askscience/comments/4vzqv6/do_we_lose_our_ability_to_remember_dreams_as_we/
{ "a_id": [ "d6495y8" ], "score": [ 2 ], "text": [ "as you get older you spend less and less time sleeping, and the time spent in REM (dreaming) sleep is proportionally less. so, knowing that alone, you would expect to notice fewer dreams (since they happen less frequently, you will notice them le...
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[ [] ]
3kmqxa
why is autotune used excessively in songs these days?
explainlikeimfive
https://www.reddit.com/r/explainlikeimfive/comments/3kmqxa/eli5_why_is_autotune_used_excessively_in_songs/
{ "a_id": [ "cuyqjvr", "cuyqk8z" ], "score": [ 6, 15 ], "text": [ "It's practically am instrument of its own at this point.\n\nUsing autotune, you can mask errors in your singing, yes, but you can also get voice effects not possible with natural voices. Many artists thus incorporate it int...
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[ [], [] ]
7ivr8d
graphene, graphite, and why one is an amazing super-material and the other is pencil lead and skateboard layers?
explainlikeimfive
https://www.reddit.com/r/explainlikeimfive/comments/7ivr8d/eli5_graphene_graphite_and_why_one_is_an_amazing/
{ "a_id": [ "dr1qgt6", "dr2qx79", "dr2ud0t" ], "score": [ 16, 2, 2 ], "text": [ "*Graphite* is many *graphene* sheets layered on top of eachother.\n\nGraphene is only a single atom thick, and this gives it some odd properties because so many electrons are exposed in identical confi...
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[ [], [], [] ]
f1w6so
how do house builders avoid weather damage while the buildings are under construction?
Whenever I see unfinished houses in a downpour all I can think about is all the places water is seeping in to cause damage. How does the potential damage get mitigated by the time a roof and siding gets added? Does the wood really just dry out enough in the sun that it is not an issue?
explainlikeimfive
https://www.reddit.com/r/explainlikeimfive/comments/f1w6so/eli5_how_do_house_builders_avoid_weather_damage/
{ "a_id": [ "fh8t2gi", "fh8xyho", "fh97yq9", "fh9ca0k" ], "score": [ 7, 13, 2, 2 ], "text": [ "you build them let it dry out. Dupont Tyvek is special sheet that allows moisture to go one way but not the other.", "Depends on what phase of construction they are in. In n...
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[ [], [], [], [] ]
12yoya
electromagnetic spectrum
explainlikeimfive
http://www.reddit.com/r/explainlikeimfive/comments/12yoya/eli5_electromagnetic_spectrum/
{ "a_id": [ "c6zaxgm", "c6zbjke" ], "score": [ 3, 2 ], "text": [ "I do suppose you should rephrase this to include what exactly it is you want to know: The electromagnetic spectrum is just a range of wavelengths (frequencies) of electromagnetic waves. There really isn't much more to say th...
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[ [], [] ]
bv4uxe
what keeps venomous/poisonous animals from harming themselves? are they born with a genetic antidote?
explainlikeimfive
https://www.reddit.com/r/explainlikeimfive/comments/bv4uxe/eli5_what_keeps_venomouspoisonous_animals_from/
{ "a_id": [ "eplbuzu", "eplufn3", "eplzcid" ], "score": [ 6, 4, 2 ], "text": [ "Some actually can harm themselves. It depends on the animal. Others are immune to their own toxin, or super resilient to it.", "Yep. I think for some, they are just resilient. So for example - not v...
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[ [], [], [] ]
1964qs
why does star wars transcend typical sci-fi fandom and hit home for so many people.
I am a huge Star Wars fan. With all the recent talk about the ongoing storyline, something occurred to me. Not only are my sci-fi buddies excited, but everyone I know is excited. My theory is that despite its sci-fi orgins; the Star Wars series hits home for a lot of people. Why is that? TELL ME. I WANT TO KNOW.
explainlikeimfive
http://www.reddit.com/r/explainlikeimfive/comments/1964qs/eli5_why_does_star_wars_transcend_typical_scifi/
{ "a_id": [ "c8l4qem", "c8l9cta", "c8lbqbd", "c8lngnd" ], "score": [ 12, 2, 2, 2 ], "text": [ "Well it was first (sort of).\n\nBefore Star Wars, Scifi in movies was very pulpy and bad.\n\nIt was proof that it could be done well.\n\nIt also has a lot of cultural significance...
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[ [], [], [], [] ]
rrxbx
What was it actually like being a spy in the Cold War?
How close does our perception of a gentlemanly and cultured spy fit into reality? What was it really like? What important information did we receive from these spies? Where they effective?
AskHistorians
http://www.reddit.com/r/AskHistorians/comments/rrxbx/what_was_it_actually_like_being_a_spy_in_the_cold/
{ "a_id": [ "c489vbv", "c48t4bw" ], "score": [ 8, 2 ], "text": [ "Also not my area of expertise completely, but while doing the Cold War you do run into them quite often:\n\n1 ) Gentlemanly and cultured spy - they existed, but not quite in the same way you might want them to exist. No suav...
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[]
[ [ "http://en.wikipedia.org/wiki/List_of_Soviet_agents_in_the_United_States" ], [] ]
6mljvl
Why don't we use exile as a punishment any more?
AskHistorians
https://www.reddit.com/r/AskHistorians/comments/6mljvl/why_dont_we_use_exile_as_a_punishment_any_more/
{ "a_id": [ "dk2t5q2", "dk378yg" ], "score": [ 1240, 42 ], "text": [ "Post-WWII, exile as a form of judicial punishment would be a violation of international law:\n\n[Article 15 of the Universal Declaration of Human Rights](_URL_3_) states that:\n\n > Everyone has the right to a nationalit...
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[ [ "http://www.bbc.co.uk/news/av/magazine-37376130/the-bbc-journalist-assassinated-with-a-poison-tipped-umbrella", "http://blogs.reuters.com/felix-salmon/2012/05/17/eduardo-saverin-joins-the-stateless-billionaires/", "http://www.newstatesman.com/culture/books/2017/01/now-there-was-no-way-back-me-strange-...
6c34z3
If electrons are so much smaller than than protons and neutrons, why can't we easily see atom nuclei with an electron microscope?
askscience
https://www.reddit.com/r/askscience/comments/6c34z3/if_electrons_are_so_much_smaller_than_than/
{ "a_id": [ "dhrnyog" ], "score": [ 13 ], "text": [ "There is a difference between the size of the electron and its wavelength. Its generally the wavelength that determines the resolution of a microscope. On top of that, the atomic core is orders of magnitude smaller than the electron cloud and th...
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[ [] ]
vhoma
Are there biomes that are theoretically possible or used to exist, but not represented on Earth currently?
askscience
http://www.reddit.com/r/askscience/comments/vhoma/are_there_biomes_that_are_theoretically_possible/
{ "a_id": [ "c54m4lb" ], "score": [ 8 ], "text": [ "The type of biome represented in a region is a function of two things: its temperature, and its precipitation. [This Chart](_URL_0_) gives an approximation of this function. Everything else you associate with a biome (the type of flora and faun...
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[ [ "http://www.marietta.edu/~biol/biomes/whittaker.jpg" ] ]
30oali
why did fever used to be such a dread and often lead to death? i just rest and drink lots of water, no antibiotics or anything.
explainlikeimfive
http://www.reddit.com/r/explainlikeimfive/comments/30oali/eli5_why_did_fever_used_to_be_such_a_dread_and/
{ "a_id": [ "cpu918q", "cpu99xw" ], "score": [ 2, 18 ], "text": [ "because you couldn't just drink tons of water. fresh, clean, easily accessible water is a fairly new thing. \nplus, most fevers were more than just a fever.", "Two reasons.\n\n1 - The illnesses we fight today are relati...
[]
[]
[ [], [] ]
5e0b51
How does a website know a credit card number is invalid?
I have noticed before that if I make a typo, it can tell that a number is invalid. How? It can also tell if a number is Visa or MasterCard. How does it know?
askscience
https://www.reddit.com/r/askscience/comments/5e0b51/how_does_a_website_know_a_credit_card_number_is/
{ "a_id": [ "da8q4q9", "da9kggl" ], "score": [ 58, 2 ], "text": [ "I actually had to write the credit card number validation algorithm as the [very first problem set](_URL_2_) in my intro CS class. Here's the gist:\n\n* American Express numbers all start with 34 or 37; MasterCard numbers a...
[]
[]
[ [ "https://en.wikipedia.org/wiki/Luhn_algorithm", "http://1.bp.blogspot.com/-TdbElQU7gxg/T8zFgVIc8nI/AAAAAAAAQ38/1tZocdiPQtE/s640/checksum+number.jpg", "https://cdn.cs50.net/2015/x/psets/1/hacker1/hacker1.html#bad_credit" ], [ "https://web.archive.org/web/20080102150024/http://www.merriampark.co...
2ic3w5
why was the citizens united ruling passed in the first place and what benefits does it provide for the average citizen?
explainlikeimfive
http://www.reddit.com/r/explainlikeimfive/comments/2ic3w5/eli5_why_was_the_citizens_united_ruling_passed_in/
{ "a_id": [ "cl0sf9s", "cl0sg5l" ], "score": [ 3, 3 ], "text": [ "For the average citizen, it arguably has negative benefits. \n\nFor big companies, it allows them to give as much money as they want to candidates in an election.\n\nAs for the reason it was made, despite the corruption inhe...
[]
[]
[ [], [] ]
fkhdjj
why do most online resources seem to be predominantly american?
explainlikeimfive
https://www.reddit.com/r/explainlikeimfive/comments/fkhdjj/eli5_why_do_most_online_resources_seem_to_be/
{ "a_id": [ "fkss59b", "fkss5p6" ], "score": [ 4, 3 ], "text": [ "America invented the Internet. American companies built the machines that ran the Internet in the early days, and still represent the vast majority of Internet developers.", "There are about 320 million Americans. Japan...
[]
[]
[ [], [] ]
xou08
Using the laws of entropy: if the universe is both expanding and cooling, does that not suggest the existence of a larger, cooler area outside the universe itself?
askscience
http://www.reddit.com/r/askscience/comments/xou08/using_the_laws_of_entropy_if_the_universe_is_both/
{ "a_id": [ "c5o9d7o" ], "score": [ 3 ], "text": [ "Just to clarify: the total entropy of the universe does not decrease as the universe expands, it is the entropy *density* that decreases. There's no violation of the laws of thermodynamics in a universe that cools as it expands, in the same way ...
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[]
[ [] ]
3hdyyb
Is Diatomaceous Earth safe for comsumption and are there any studies that show if it has actual health benefits?
I read an article that said it had a lot of health benefits but when i looked it up, I found a lot of sites about it being a pesticide. I'm trying to find credible info on its consumption.
askscience
http://www.reddit.com/r/askscience/comments/3hdyyb/is_diatomaceous_earth_safe_for_comsumption_and/
{ "a_id": [ "cu6sqio" ], "score": [ 3 ], "text": [ "The answer is actually both yes and no. If you are going to consume Diatomaceous earth it must be of a food grade quality or it's not recommended from consumption. Finding sources that are credible will likely be a bit challenging as natural prod...
[]
[]
[ [] ]
6ygh74
Has anyone ever attempted to fuse heavy elements by artificial nucleosynthesis? What would make such a process difficult?
askscience
https://www.reddit.com/r/askscience/comments/6ygh74/has_anyone_ever_attempted_to_fuse_heavy_elements/
{ "a_id": [ "dmn79jr" ], "score": [ 27 ], "text": [ "Yes, we do this all the time using particle accelerators. This is how superheavy elements are produced, for example.\n\nThe Coulomb barrier, the negative Q-values, and the kinematic thresholds pose problems for these reactions happening in natur...
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[]
[ [] ]
a3396w
Late Imperial China had a tax rate of only 3-4%. How did they pay for extensive bureaucracies and large armed forces with such low taxes?
The Ming and Qing dynasties, according to [Wikipedia, citing the Cambridge History of China](_URL_0_), collected only 3-4% as a percentage of income for land taxes. Yet they had extensive bureaucracies going down to the centrally appointed country magistrates and large "permanent" armed forces in the hundreds of thous...
AskHistorians
https://www.reddit.com/r/AskHistorians/comments/a3396w/late_imperial_china_had_a_tax_rate_of_only_34_how/
{ "a_id": [ "eb38btw", "eb3nd0i", "eb3ozyv" ], "score": [ 16, 2, 4 ], "text": [ "The short answer is that by the mid-1850s, they couldn't, but then found alternatives.\n\nYou must excuse me for failing to give exact figures; I'm on holiday and can't access many of my books, includi...
[]
[ "https://en.wikipedia.org/wiki/Taxation_in_premodern_China" ]
[ [], [], [] ]
a9ccdr
Why do dogs tilt their heads when curious / confused?
askscience
https://www.reddit.com/r/askscience/comments/a9ccdr/why_do_dogs_tilt_their_heads_when_curious_confused/
{ "a_id": [ "ecjz6zz" ], "score": [ 80 ], "text": [ "This was answered by 99 trumpets (don't want to ping them)\n > Biologist here. Head tilting allows an animal to gain information about the vertical placement of the sound (how far up/down it is, relative to the axis of the skull). It is assumed ...
[]
[]
[ [ "https://np.reddit.com/r/LifeProTips/comments/3vsc6p/lpt_when_trying_to_take_a_picture_of_your_dog_or/cxqxp40/", "https://www.reddit.com/r/LifeProTips/comments/3vsc6p/lpt_when_trying_to_take_a_picture_of_your_dog_or/cxqxp40/" ] ]
20e6d6
[Serious] Was farting considered gross in Medieval times? (x-post from /r/askashittydoctor)
The title kind of says it all. As sewerage wasn't invented yet and body odors were common, were farts still considered rude/ gross?
AskHistorians
http://www.reddit.com/r/AskHistorians/comments/20e6d6/serious_was_farting_considered_gross_in_medieval/
{ "a_id": [ "cg2l8e6" ], "score": [ 6 ], "text": [ "It seems to have been, at least in certain contexts. The [Urbanus Magnus](_URL_0_), an etiquette book written in the early 13th century, advised people not to fart indoors." ] }
[]
[]
[ [ "http://bedejournal.blogspot.co.uk/2009/04/urbanus-magnus-civilised-man.html" ] ]
9rge7q
Why do electrical arcs produce their signature buzzing sound?
askscience
https://www.reddit.com/r/askscience/comments/9rge7q/why_do_electrical_arcs_produce_their_signature/
{ "a_id": [ "e8gscrp", "e8ieli9" ], "score": [ 20, 4 ], "text": [ "That’s the sound of the wire buzzing at 60hz or whatever the frequency of our English counter parts use. Your electricity in the overhead wires is alternating current and it alternates at a frequency of 60Hz and if the curr...
[]
[]
[ [], [ "https://youtu.be/_fTC_Ud_k3U?t=458", "https://www.youtube.com/watch?v=HdwcZX07NFk", "https://www.youtube.com/watch?v=DZjNI_48rY0" ] ]
dnqt2p
Was the Amerivan Revolution unpopular in Britain during the war?
AskHistorians
https://www.reddit.com/r/AskHistorians/comments/dnqt2p/was_the_amerivan_revolution_unpopular_in_britain/
{ "a_id": [ "f5qr8y5" ], "score": [ 2 ], "text": [ "In a nutshell, yes. \nVery. \n\nThe origins of British opposition to the America War of Independence are varied, but to simplify brutally:\nYou had large groups of Protestant merchants who by inclination and attitude, felt a large degree of sympa...
[]
[]
[ [] ]
9y5d9z
Does the body consume more calories when it's recovering from a surgery or an accident ?
askscience
https://www.reddit.com/r/askscience/comments/9y5d9z/does_the_body_consume_more_calories_when_its/
{ "a_id": [ "ea0uu7l", "ea39foo" ], "score": [ 3, 2 ], "text": [ "I can answer this on a cellular level but I'm not too well-versed in physiology. To heal cuts and other tissue damage cells will generally undergo mitosis at a much higher rate than normal. Going through DNA synthesis and mi...
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[]
[ [], [] ]
5z4dft
what are operating system or network backdoors?
Also what actually a backdoor is? Like a bug in code?
explainlikeimfive
https://www.reddit.com/r/explainlikeimfive/comments/5z4dft/eli5_what_are_operating_system_or_network/
{ "a_id": [ "dev72yh", "devbfs6", "devinrw" ], "score": [ 2, 2, 2 ], "text": [ "Back door is just alternative access to some part of a program / software / website that's used to facilitate the programmer to edit that part.\n\nRegular users should not have access to it: they should...
[]
[]
[ [], [], [] ]
71nysr
Were the early American colonists disproportionately from any specific places in England or were all places in England fairly equally represented in the American colonies?
Were there any specific areas of origin in England that were over or under represented? If so what were they and what was the reason for this disparity in representation?
AskHistorians
https://www.reddit.com/r/AskHistorians/comments/71nysr/were_the_early_american_colonists/
{ "a_id": [ "dnecid3" ], "score": [ 2 ], "text": [ "The best way to think about early American colonists is to see them in terms of their individual colonies, which often had very different origins in terms of why they were settled, and thus, by whom. Many of these early colonies were indeed stron...
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[ [] ]
bgmw5l
what is the point of medications that you need to dissolve under your tongue before swallowing? isn’t it all going to the same place anyway?
I’ve been taking a new brand of melatonin, that says to hold it under your tongue for 30 mins before you swallow it. The previous brand I was using didn’t say to do that, so what’s the difference?
explainlikeimfive
https://www.reddit.com/r/explainlikeimfive/comments/bgmw5l/eli5_what_is_the_point_of_medications_that_you/
{ "a_id": [ "elm1iph", "elm24eh", "elm2u64" ], "score": [ 9, 4, 19 ], "text": [ "It dissolves faster and passes into your bloodstream by way of the veins under your tongue to take effect faster.", "Absorbed in to your blood stream via the veins under your tongue versus going th...
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[]
[ [], [], [] ]
3tew69
how do animals like bees, butterflies and eel completely change their physical structure when moving from larva to adult form?
explainlikeimfive
https://www.reddit.com/r/explainlikeimfive/comments/3tew69/eli5how_do_animals_like_bees_butterflies_and_eel/
{ "a_id": [ "cx5kc17" ], "score": [ 2 ], "text": [ "Ok, once an insect is in a cocoon/chrysalis/whatever, it pretty much *melts*. Well, not completely, but most of it does. Just turns back to goo, or rather into the basic building blocks of an organic entity. But, again, not all of it. Some parts ...
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[ [] ]
3prldp
why is there so much air below ice?
I've noticed that when water puddles freeze there is often a very thin layer of ice with an air chamber many times as thick below it. I would expect that ice should be touching water instead. Why do those airbags form?
explainlikeimfive
https://www.reddit.com/r/explainlikeimfive/comments/3prldp/eli5_why_is_there_so_much_air_below_ice/
{ "a_id": [ "cw8tk8i" ], "score": [ 2 ], "text": [ "The water level of the puddle has gone down since the ice formed. Either some soaked into the ground, or it found some channel to drain away through." ] }
[]
[]
[ [] ]
3ak10r
If an alpha particle is a helium nucleus, can it combine with electrons to form helium?
askscience
http://www.reddit.com/r/askscience/comments/3ak10r/if_an_alpha_particle_is_a_helium_nucleus_can_it/
{ "a_id": [ "csdc5vf", "csdmxtt", "csdo3ql", "csdsf3o" ], "score": [ 1003, 9, 64, 5 ], "text": [ "You got it boss. A helium nucleus + 2 electrons = helium atom. ", "Few references: \n[-Where nuclear engineering meets materials science](_URL_1_) \n[-Radiation Damage/Ma...
[]
[]
[ [], [ "http://www.sciencedirect.com/science/article/pii/S0022311514001822", "http://nucleararcher.blogspot.co.uk/2010/04/some-basic-ideas-in-nuclear-material.html", "https://cams.llnl.gov/cams-competencies/radiation-damage-materials-modification" ], [], [] ]
43ufvs
the top candidates for the upcoming presidential election. i have no idea who to vote for, because i pretty much disagree with all them on at least one major issue.
explainlikeimfive
https://www.reddit.com/r/explainlikeimfive/comments/43ufvs/eli5_the_top_candidates_for_the_upcoming/
{ "a_id": [ "czl0dy7", "czl0nu4" ], "score": [ 7, 5 ], "text": [ "The thing is, it's unreasonable to expect 100% agreement with a candidate. If that's what you really want, you'll need to run yourself because no one else will ever agree with you on every issue.\n\nSo you need to set prior...
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[]
[ [], [] ]
5n2zby
How was 60 to 80 percent of a Russian cavalry corps destroyed in a single day while assembling in formation?
[As per Wikipedia:](_URL_0_) "...60 to 80 percent of the 6th Cavalry Corps were destroyed on June 22 as they struggled to assemble in formation)." How can most of a cavalry corps be destroyed in a single day? Would they not be able to retreat? Could it have been ambush of a camp? I'm just confused as to how such a l...
AskHistorians
https://www.reddit.com/r/AskHistorians/comments/5n2zby/how_was_60_to_80_percent_of_a_russian_cavalry/
{ "a_id": [ "dc8il7h" ], "score": [ 10 ], "text": [ "The 6th Cavalry Corps was part of the 10th Army in 1941. Now, I can't actually properly answer your question because the sources I've seen don't entirely agree with the statement that the 6th was largely destroyed trying to assemble in formation...
[]
[ "https://en.wikipedia.org/wiki/Horses_in_World_War_II#Debacle_of_1941" ]
[ [] ]
43esqw
can someone explain the whole finebros controversy?
explainlikeimfive
https://www.reddit.com/r/explainlikeimfive/comments/43esqw/eli5can_someone_explain_the_whole_finebros/
{ "a_id": [ "czho3x8" ], "score": [ 6 ], "text": [ "They did something that was unoriginal but funny. \n\nGot a following and then told the government they own the format and title kids react to \"xyz\". \n\nThe government said sure. Other people were doing the same unoriginal but funny idea, like...
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[ [] ]
pciiw
Can eating certain foods cleanse your body of heavy metals?
I was told by someone that cilantro will take heavy metals out of your body. I thought about it and couldn't figure how it would work if true. I did some searching online but couldn't find any reputable sources to support such a claim. Every site that stated it looked like new age health stuff trying to sell you pills ...
askscience
http://www.reddit.com/r/askscience/comments/pciiw/can_eating_certain_foods_cleanse_your_body_of/
{ "a_id": [ "c3o9w3f", "c3oa4f2" ], "score": [ 2, 2 ], "text": [ "Nope - utter bullshit.\n\nThe only effective treatment (sometimes only somewhat) is chelation therapy (_URL_0_)", "Heavy metals usually bind to polar organic molecules in our bodies, cilantro will not change this.\n\nIt'...
[]
[ "http://en.wikipedia.org/wiki/Chelation_therapy" ]
[ [ "http://en.wikipedia.org/wiki/Chelation_therapy#Medically_diagnosed_heavy_metal_poisoning" ], [] ]
1jkcsd
why coffee shop coffee tastes so much better
Why is it that the coffee that's sitting in the dispenser for hours at the downtown coffee shop tastes like the nectar of the gods, and my fresh brewed (machine) coffee tastes like bitter burnt ass water?
explainlikeimfive
http://www.reddit.com/r/explainlikeimfive/comments/1jkcsd/eli5_why_coffee_shop_coffee_tastes_so_much_better/
{ "a_id": [ "cbfi7l1", "cbfius4" ], "score": [ 5, 3 ], "text": [ "It's the coffee beans. Coffee shops buy higher quality whole beans than you are likely to purchase yourself (although purchasing quality whole beans is an option, they just cost more and should be handled differently).", ...
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[ [], [ "http://www.bonavita.ca/bonavita_8_cup_coffee_maker_glass.htm", "http://www.amazon.com/Baratza-Virtuoso-Conical-Coffee-Grinder/dp/B000FLWCOG" ] ]
ch69sn
why does english have so many strange and varied collective nouns for animals?
It just seems like itd make more sense to have one simple word for all or at least a handful. School for fish. Flock for all birds. Herd for mammals? But no a group of cheetahs is called a coalition? A group of ferrets is a business? These just seem like jokes and considering most of us have never used or heard of them...
explainlikeimfive
https://www.reddit.com/r/explainlikeimfive/comments/ch69sn/eli5_why_does_english_have_so_many_strange_and/
{ "a_id": [ "eupsbv1", "eupvkkj", "euqfs6i" ], "score": [ 28, 8, 2 ], "text": [ " > These just seem like jokes \n\nPretty much, yes. [Terms of venery](_URL_0_) are essentially an in-joke from the 1400s that happened to get written down. Some modern English speakers like them, most ...
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[]
[ [ "https://en.wikipedia.org/wiki/Collective_noun#Terms_of_venery" ], [], [] ]
6w040p
Why did the landing craft on D-Day open straight out into the open where the soldiers could all be mown down by machine gun fire? Was there any plan to limit their exposure when landing on the beach?
AskHistorians
https://www.reddit.com/r/AskHistorians/comments/6w040p/why_did_the_landing_craft_on_dday_open_straight/
{ "a_id": [ "dm53cxj" ], "score": [ 16 ], "text": [ "The plan, such as it was, was to barrage the defenders with aircraft, naval gunfire support and then rockets and other artillery from landing vessels themselves. That was supposed to suppress the defenders enough to give the lads attacking somet...
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[]
[ [ "https://www.reddit.com/r/AskHistorians/comments/620zob/why_did_the_american_forces_land_on_normandy_with/dfix9nk/" ] ]
5suh9p
analog to digital converter
ELI5: How is an analog to digital converter work? Am I wrong in assuming the output as a digital bit i.e. 1 or 0? Can you cite an example?
explainlikeimfive
https://www.reddit.com/r/explainlikeimfive/comments/5suh9p/eli5_analog_to_digital_converter/
{ "a_id": [ "ddhvvua", "ddhw289", "ddhx5sn", "ddi1sup", "ddikz7c" ], "score": [ 6, 2, 2, 2, 2 ], "text": [ "Input: a continuous signal, like a voltage\n\nOutput: a binary number that indicates the measurement of the voltage. Usually a number of bits, like 8 bits or...
[]
[]
[ [], [], [ "https://en.wikipedia.org/wiki/Resistor_ladder" ], [ "http://i.imgur.com/ymd74sx.jpg", "https://en.wikipedia.org/wiki/Operational_amplifier_applications#Summing_amplifier" ], [] ]
35cyah
dr. oz's credibility (or lack thereof)
I hear a lot about Dr. Oz being illegitimate and spreading false information. Conversely, I know people who act as if everything that comes out of his mouth is a universal truth. Can someone explain, using true facts and information from an unbiased perspective, how credible Dr. Oz really is?
explainlikeimfive
http://www.reddit.com/r/explainlikeimfive/comments/35cyah/eli5_dr_ozs_credibility_or_lack_thereof/
{ "a_id": [ "cr39akr", "cr39lis", "cr3azhv" ], "score": [ 8, 6, 2 ], "text": [ "He has been paid by multiple supplement companies to restate their unsubstantiated claims. It's a disgrace. Last week tonight did a fantastic episode and follow up on it. Please have those you know that...
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[]
[ [ "https://youtu.be/WA0wKeokWUU", "https://youtu.be/TucUMpWWe8A" ], [ "http://www.washingtonpost.com/news/morning-mix/wp/2014/12/19/half-of-dr-ozs-medical-advice-is-baseless-or-wrong-study-says/" ], [] ]
476w8i
Does anyone know of a good book/report detailing the history of England from the Romans leaving until 1066?
Like perhaps a historical review of the Anglo Saxon chronicles but without the dramatization and fiction?
AskHistorians
https://www.reddit.com/r/AskHistorians/comments/476w8i/does_anyone_know_of_a_good_bookreport_detailing/
{ "a_id": [ "d0aqbv1" ], "score": [ 2 ], "text": [ "My personal recommendation would be R. Fleming, *Britain After Rome*. It makes good use of new archaeological evidence to tell a compelling historical narrative, it's recent, it's credible, and it's also inexpensive and very readable.\n\nIf you'r...
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[]
[ [] ]
996498
Pan-European Identity prior to the European Union
While it would be disingenuous to directly equate George of Podebrady with the modern day EU, I've heard some talk floated that he had ideas pertaining to a Pan-European institution. Were there any other notable examples of monarchs, religious leaders, or scholars advocating for or theorizing about Pan-European institu...
AskHistorians
https://www.reddit.com/r/AskHistorians/comments/996498/paneuropean_identity_prior_to_the_european_union/
{ "a_id": [ "e4lot1x" ], "score": [ 7 ], "text": [ "It would be quite tempting, there, to exclaim \"of course!\"; yet there is a dangerous teleological trap to be wary of. As you yourself noticed, it is not because a project or vision of some kind of union has been in the past proposed *in Europe*...
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[]
[ [ "https://en.wikipedia.org/wiki/Europa_regina#/media/File:Europe_As_A_Queen_Sebastian_Munster_1570.jpg", "https://en.wikipedia.org/wiki/Hussites" ] ]
6ol3gc
In the 1860s , Teams of Engineers Used Human-Powered Screwjacks to Lift Entire City Blocks of Chicago. Where Could I Find Technical Information About How This Was Accomplished?
[I was reading a bit](_URL_0_) about all of the tremendous civil engineering taking place in Chicago, even before the fire, and I wanted to know how the screwjacks used were put into position in the first place. I couldn't find any firsthand sources outside of the Chicago Tribune archives, which tended to focus more on...
AskHistorians
https://www.reddit.com/r/AskHistorians/comments/6ol3gc/in_the_1860s_teams_of_engineers_used_humanpowered/
{ "a_id": [ "dkj0phg", "dkj7vog" ], "score": [ 2, 2 ], "text": [ "The site you found is actually about the most comprehensive research I've ever found on the effort (you did follow [the links at the end,](_URL_0_) right?) It's possible there was a contemporary report in *Scientific Americ...
[]
[ "http://users.ox.ac.uk/~sedm1912/lch.html" ]
[ [ "http://users.ox.ac.uk/~sedm1912/csc.html" ], [ "https://www.wolfehousebuildingmovers.com/news/chicagos-harriet-f-rees-house-relocation/", "https://www.wolfehousebuildingmovers.com/project/rees-house-chicago/" ] ]
162hgq
Islamic historians: What was the age of Aisha when she married Mohammed?
This may seem like a rather controversial question and it may offend people of faith which is not what I'm trying to do at all. While researching Islam, I found many different reports on her age when she married the prophet, some say she was married to the prophet at 6 and it was consummated at 9. Others reports say sh...
AskHistorians
http://www.reddit.com/r/AskHistorians/comments/162hgq/islamic_historians_what_was_the_age_of_aisha_when/
{ "a_id": [ "c7s38tv", "c7s6egu" ], "score": [ 20, 7 ], "text": [ "The marriage contract was written when she was 6 and she moved in with him after the migration at age 9. \n\nActually it's only very recently that this has become controversial. None of the early sources felt the need to ju...
[]
[]
[ [], [] ]
201k3r
why do politicians support charter schools? do they not have faith in public schools?
Charter schools are tax payer funded schools that make a profit and have a strong lobby. I see they are supported by republicans and democrats like Gov. Cuomo in NY, which was totally surprising to me. I think it is a waste of tax payer money to give to private/public ventures. Is there something I'm missing? Why are c...
explainlikeimfive
http://www.reddit.com/r/explainlikeimfive/comments/201k3r/eli5_why_do_politicians_support_charter_schools/
{ "a_id": [ "cfyxian" ], "score": [ 6 ], "text": [ "There are charter schools, then there are charter schools. As a parent, I chose a charter school for my son because of their charter - they are run as a non-profit, by a council made of parents elected by their peers. We get some funding from the...
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[]
[ [] ]
2eqzfh
what happens when a car engine is "broken in"? do engines even get broken in?
Some say they are faster, get better fuel economy, etc. Then there are two apparent break-in periods. 1 being the factory 3500 mile (give or take) break it, and then the one that owners supposedly get way down the line. Are either of these real things?
explainlikeimfive
http://www.reddit.com/r/explainlikeimfive/comments/2eqzfh/eli5what_happens_when_a_car_engine_is_broken_in/
{ "a_id": [ "ck235x3" ], "score": [ 2 ], "text": [ "Metal parts that contact each other have tiny manufacturing defects, stich as burrs. When they are assembled into an engine and the engine runs, they rub against each other. Over time, some of the defects are worn away and the parts move again...
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[]
[ [] ]
3ibci1
why can't noise-cancellation be achieved with an app
There are many notable noise-canceling headphones that achieve this with hardware. Why isn't there an app that does that with the existing hardware of the smartphone?
explainlikeimfive
http://www.reddit.com/r/explainlikeimfive/comments/3ibci1/eli5_why_cant_noisecancellation_be_achieved_with/
{ "a_id": [ "cuewtir" ], "score": [ 2 ], "text": [ "Active noise cancellation headphones rely on small microphones on the earcups of the headphones to work out what noise they're trying to cancel out. If you're relying on the microphone on a phone headset, or even the one on the handset itself, yo...
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1eowot
Did English Civil War soldiers wear ribbons in their hair?
I was told by a colleague that some soldiers in the English Civil War would grow their hair longer on the left and would tie a ribbon from their loved one in it. Can anyone provide an image that I can copy? I'm going to a reenactment this weekend and would like to imitate the look. Thanks in advance.
AskHistorians
http://www.reddit.com/r/AskHistorians/comments/1eowot/did_english_civil_war_soldiers_wear_ribbons_in/
{ "a_id": [ "ca2g7rf" ], "score": [ 2 ], "text": [ "I have never heard of this practice before. I am fully aware of ribbons or sashes being worn around the waist or abdomen to show allegiance but nothing worn in the hair, especially for something so personal or sentimental." ] }
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3sn3ta
Why is the Israeli military so good?
From the Bekaa valley turkey shoot to the Six day war to Operation Opera, the Israeli military seems to be ridiculously ahead of its neighbours. Even during the Yom Kippur war when caught with their pants down against new missile technology, they turned the tables and were only prevented from destroying the enemy throu...
AskHistorians
https://www.reddit.com/r/AskHistorians/comments/3sn3ta/why_is_the_israeli_military_so_good/
{ "a_id": [ "cwyxrek" ], "score": [ 13 ], "text": [ "The usual answer points out the financial and technical help Israel receives from the US, which should certainly not be neglected, but was limited before 1967 and doesn't really explain much, since the US also help many militaries and government...
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[ "http://www.meforum.org/441/why-arabs-lose-wars" ]
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c2da9l
We get crushed if we go too deep into the ocean. What happens to creatures that live too deep in the ocean if they are brought to the surface?
Also, how tf do they exist with all that pressure?
askscience
https://www.reddit.com/r/askscience/comments/c2da9l/we_get_crushed_if_we_go_too_deep_into_the_ocean/
{ "a_id": [ "erlydw4" ], "score": [ 4 ], "text": [ "They're uniquely adapted for the pressure. Many of them don't have \"air pockets\" in their body so that pressure doesn't affect them like it does us. Some organisms that don't love in the abyss but in relatively deep water can survive being br...
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ai0joe
Is it fair to say that Timur/Tamerlane was one of the greatest conquerors in history? What were his greatest achievements?
I’ve heard that he could be and should be considered in the same breath as even Alexander the Great. Would you say this is fair?
AskHistorians
https://www.reddit.com/r/AskHistorians/comments/ai0joe/is_it_fair_to_say_that_timurtamerlane_was_one_of/
{ "a_id": [ "eeku1dc" ], "score": [ 19 ], "text": [ "Timur is almost the archetype of the cruel Central Asian conqueror, building on a tradition started with Alp Arslan and ended with Nader Shah. As a military commander, he was unparalleled by his contemporaries, and often used his military brilli...
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1peqny
If something has a non-zero chance of happening, will it definitely happen given an infinite time period?
It seem intuitive that given infinite time even the most unlikely events will happen. Flipping heads 1 trillion times in a row followed by flipping tails 100 trillion times in a row (with a fair coin). Or perhaps winning the lottery every day for 5 years. However, I have also heard that things like this can 'just not ...
askscience
http://www.reddit.com/r/askscience/comments/1peqny/if_something_has_a_nonzero_chance_of_happening/
{ "a_id": [ "cd1oq5w" ], "score": [ 28 ], "text": [ "There are two very different questions here. :\n\n > It seem intuitive that given infinite time even the most unlikely events will happen. Flipping heads 1 trillion times in a row followed by flipping tails 100 trillion times in a row (with a ...
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2ljwfp
Why do communist states so often lead to dictatorships?
AskHistorians
http://www.reddit.com/r/AskHistorians/comments/2ljwfp/why_do_communist_states_so_often_lead_to/
{ "a_id": [ "clviom5", "clvmi7g" ], "score": [ 5, 4 ], "text": [ "The most challenging part of any revolution is re-establishing order; just look at the French Revolution or the USA's original Articles of Confederation. Marx and Engels foresaw this in the *Communist Manifesto*:\n\n > If th...
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9hsgrt
how do surgeons remember every little step for every surgery they may need to perform?
explainlikeimfive
https://www.reddit.com/r/explainlikeimfive/comments/9hsgrt/eli5_how_do_surgeons_remember_every_little_step/
{ "a_id": [ "e6e55lt", "e6eaq6s" ], "score": [ 5, 2 ], "text": [ "They usually specialize in just a few operations, and yes there are checklists. For more complicated operations there may be people assigned specifically to the logistics of tools and staff coming and going from the operati...
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6tupl4
Were King James I and George Villiers lovers?
AskHistorians
https://www.reddit.com/r/AskHistorians/comments/6tupl4/were_king_james_i_and_george_villiers_lovers/
{ "a_id": [ "dlnwh1a" ], "score": [ 3 ], "text": [ "BTW, there was [an answer about this](_URL_0_) just a few days ago by /u/whateverismyusername." ] }
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[ [ "https://www.reddit.com/r/AskHistorians/comments/6sofpk/is_there_any_proof_that_king_james_vi_of_scotland/dlecqyw/?context=3" ] ]
39uxnt
what's that feeling in your testicles when you drive quickly over an incline in the road?
You know what I'm talking about.
explainlikeimfive
http://www.reddit.com/r/explainlikeimfive/comments/39uxnt/eli5_whats_that_feeling_in_your_testicles_when/
{ "a_id": [ "cs6o28k", "cs6u457" ], "score": [ 10, 4 ], "text": [ "I'm not sure about testicles, but usually it's a feel in the stomach area. \n\nYou're in a small free fall so your organs (and the liquid in them) are moving about without the gravity to keep them pinned down like they norm...
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fyn71q
why does someone’s pulse randomly get very strong on random parts of the body?
explainlikeimfive
https://www.reddit.com/r/explainlikeimfive/comments/fyn71q/eli5_why_does_someones_pulse_randomly_get_very/
{ "a_id": [ "fn0u6xi" ], "score": [ 2 ], "text": [ "Those places are where an artery is sufficiently close to the surface and/or is sufficiently large, to have a pulse strong enough to detect by touch." ] }
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1cz05h
How feasible would it be to use a weather balloon/rocket combination to put a 1/2 kilogram satellite into low earth orbit?
Having seen some of the near space photography done with weather balloons I am left wondering how much more would be required to transition from such a high altitude into orbit? I would think that having gained such a significant proportion of orbital altitude above thick atmosphere that it would be somewhat more strai...
askscience
http://www.reddit.com/r/askscience/comments/1cz05h/how_feasible_would_it_be_to_use_a_weather/
{ "a_id": [ "c9lbwb7" ], "score": [ 2 ], "text": [ "I think its feasible, but not practical to accomplish. The main reasons have to deal with the fact that the balloon is losing lift exponentially as you get further away from sea level such that by the time you reach 250,000ft (47.348miles) you'l...
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3o0ov4
Is the pressure near the underwater mountain different than the pressure when there's no mountain?
I am talking about the pressure just next to the bottom of the mountain
askscience
https://www.reddit.com/r/askscience/comments/3o0ov4/is_the_pressure_near_the_underwater_mountain/
{ "a_id": [ "cvtcuoh" ], "score": [ 3 ], "text": [ "It depends. If the water is perfectly still, then yes, the pressure on the ocean floor would be the same, mountain or no mountain. This is because the only contribution to the pressure at that point is the column of water stacked immediately abov...
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[ [ "https://en.wikipedia.org/wiki/Bernoulli%27s_principle" ] ]
b1defy
Why is Norse mythology so well-known compared to other contemporaneous Germanic religions?
AskHistorians
https://www.reddit.com/r/AskHistorians/comments/b1defy/why_is_norse_mythology_so_wellknown_compared_to/
{ "a_id": [ "eil3vi8", "eil7nhb" ], "score": [ 780, 98 ], "text": [ "In very short answer: Shortage of the sources. Norse mythology has 'relatively' abundant written (textual) sources compared with next to none reliable for continental German or very fragmentary Anglo-Saxon one, though rec...
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[ [ "https://www.reddit.com/r/AskHistorians/comments/arzthx/howwhy_was_christianity_able_to_replace_pagan/", "https://www.reddit.com/r/AskHistorians/comments/afi9lp/why_did_snorri_write_the_prose_edda/", "http://daten.digitale-sammlungen.de/~db/bsb00000876/images/index.html?seite=60", "https://www.red...
23qhrj
Can anyone help my grandfather find a castle he was near during WWII? He was in the 22nd Infantry Regiment of the 4th Infantry Division.
I have tried for a few years now to find a photo of a castle my grandfather was stationed near during WWII with no success. He is getting older and I am running out of options, it would mean the world to him. He was in the 22nd Infantry Regiment of the 4th Infantry Division. He remembers being near this castle but not ...
AskHistorians
http://www.reddit.com/r/AskHistorians/comments/23qhrj/can_anyone_help_my_grandfather_find_a_castle_he/
{ "a_id": [ "cgzqym3", "cgzrr88" ], "score": [ 5, 3 ], "text": [ "Well, this is kind of a shot in the dark but...\n\n_URL_1_ Puts them in the Moselle Valley Dec.3 -7 of 1944. \n\nThe Moselle Valley has a castle [[_URL_0_\n\n(sorry I'm not sure how to format links in reddit)\n\nThere is a ...
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[ [ "https://www.google.com/search?q=Moselle+Valley&client=firefox-a&hs=W5s&rls=org.mozilla:en-US:official&channel=sb&tbm=isch&imgil=1bqv7rIGXa2U_M%253A%253Bhttps%253A%252F%252Fencrypted-tbn3.gstatic.com%252Fimages%253Fq%253Dtbn%253AANd9GcRQt6JtpgzOqeU6UE3Sck6v8BPOQw6Z2YcybYFjeJKhfin1RF3pk...
1bvsuv
that feeling you get in the pit of your stomach that something has gone wrong or is going to
Pretty simple, that feeling you get that something has gone wrong somewhere or is going to go wrong, I've only had this feeling a few times and last time I had it I broke my collarbone.
explainlikeimfive
http://www.reddit.com/r/explainlikeimfive/comments/1bvsuv/eli5_that_feeling_you_get_in_the_pit_of_your/
{ "a_id": [ "c9aja78" ], "score": [ 5 ], "text": [ "This is called \"confirmation bias\". Our brains are very complex pattern-recognition machines. Often we associate unrelated events to real world results, like a lucky jersey causing our favored team to win. In this case you felt uneasy and then ...
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56qold
why does every single company make you sign up with a credit card for a free trial?
Deters me more than making me want to sign up more..
explainlikeimfive
https://www.reddit.com/r/explainlikeimfive/comments/56qold/eli5_why_does_every_single_company_make_you_sign/
{ "a_id": [ "d8lku4u", "d8lkve7", "d8ll367", "d8lp6sv" ], "score": [ 15, 4, 13, 6 ], "text": [ "Most times the free \"trial\" is actually a subscription where the first month is free, and you're automatically billed afterwards if you don't cancel before then.\n\nIt's shady ...
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u5rvo
baseball stats
Reddit, I'm fairly "sports literate" for a girl but I did not grow up with baseball. Living in Phoenix I developed a love for the game by going to spring training games every year but only recently have I started paying attention during the regular season. I understand the basics of how the game is played, how runs ...
explainlikeimfive
http://www.reddit.com/r/explainlikeimfive/comments/u5rvo/eli5_baseball_stats/
{ "a_id": [ "c4skamq", "c4sm7wc" ], "score": [ 3, 2 ], "text": [ "I'm more than willing to help but I really think it would be more efficient for both of us if you named things you didn't know and I explained them to you. It helps no one if I explain in detail something you already know.\...
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[ "MLB.com" ]
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bw99hh
what is the reasoning behind us getting excited when meeting celebrities, asking them for photos, signatures, and such?
explainlikeimfive
https://www.reddit.com/r/explainlikeimfive/comments/bw99hh/eli5_what_is_the_reasoning_behind_us_getting/
{ "a_id": [ "epwmys3" ], "score": [ 2 ], "text": [ "For the same reason that a person may get excited if they see a super rare car, or rare animal, or an astronomical phenomena that only occurs every 100 years. It is an unusual occurrence that may only happen a couple of times within your life tim...
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64og67
how does an antibiotic know how to destroy infections in random places in the body?
How does the antibiotic even find the infection and does it just flat out kill infection?
explainlikeimfive
https://www.reddit.com/r/explainlikeimfive/comments/64og67/eli5how_does_an_antibiotic_know_how_to_destroy/
{ "a_id": [ "dg3sjk9", "dg3t0cy", "dg3zq8v", "dg404mb", "dg44oa2", "dg54hwi" ], "score": [ 55, 19, 22, 2, 2, 2 ], "text": [ "It affects your whole body. Some people suffer adverse affects after taking antibiotics because they can throw off your entire syste...
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56bh0r
what defines a different species ?
For example, there's like 350,000+ species of beetles, but I'm pretty sure it's impossible for all of them to look different to one another. So there are lots of beetles that are considered different species but look exactly the same to the naked eye. I've also read that species are considered different when they can'...
explainlikeimfive
https://www.reddit.com/r/explainlikeimfive/comments/56bh0r/eli5_what_defines_a_different_species/
{ "a_id": [ "d8hvx04" ], "score": [ 6 ], "text": [ "This is actually a very [hard question](_URL_0_) because the real answer is that nature doesn't provide a hard, definitive line. Life exists on a rather continuous spectrum and any lines we draw between \"species\" are just ones humans have made ...
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[ [ "https://en.wikipedia.org/wiki/Species_problem" ] ]
2nvz71
Why were the Indians so weak that Europeans were so able to conquer their whole continent?
AskHistorians
http://www.reddit.com/r/AskHistorians/comments/2nvz71/why_were_the_indians_so_weak_that_europeans_were/
{ "a_id": [ "cmhg774", "cmhs7ho" ], "score": [ 6, 4 ], "text": [ "Just to clarify- do you mean Indians or the indigenous peoples of the Americas? Those are each very different stories.", "If you mean Indians in India, they weren't weak, just disunited. The British arrived at a lucky m...
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6s93a5
Why are so few cave paintings of people?
I've recently been enjoying looking at various cave paintings, particularly from Europe. The detail and skill of many of them are absolutely astonishing. However, I suddenly realised that I'd not seen any of people - only animals. Looking around I found some aboriginal drawings of people but that's about it - why are...
AskHistorians
https://www.reddit.com/r/AskHistorians/comments/6s93a5/why_are_so_few_cave_paintings_of_people/
{ "a_id": [ "dlazwo2", "dlb31vi" ], "score": [ 8, 7 ], "text": [ "You might get a good answer here, but I recommend cross-posting this to r/AskAnthropology.", "We can't be sure why this is the case because the artists left no written record of what they were thinking or what motivated ...
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[ [], [ "http://www.visual-arts-cork.com/prehistoric/lascaux-cave-paintings.htm", "https://en.wikipedia.org/wiki/The_Sorcerer_(cave_art)" ] ]
6hoopj
why some videogames take a long time to install but other games can be put in and played instantly
For example the wii plays games without any installation but games on the Xbox and PlayStation take time to install
explainlikeimfive
https://www.reddit.com/r/explainlikeimfive/comments/6hoopj/eli5_why_some_videogames_take_a_long_time_to/
{ "a_id": [ "dizxbnf" ], "score": [ 3 ], "text": [ "If it has to install, that means it's putting at least some (but usually most, I think?) of the game files on the consoles hard drive and then running the game off that. The game doesn't need the disc to play after that but makes you insert it an...
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20bvr9
construction workers of reddit, what is that tripod thing i see you guys using every other day for hours on end on roads and construction sites?
A few Google searches and I *think* its called an electric theodolite? Sure looks like that!
explainlikeimfive
http://www.reddit.com/r/explainlikeimfive/comments/20bvr9/eli5_construction_workers_of_reddit_what_is_that/
{ "a_id": [ "cg1pauh" ], "score": [ 9 ], "text": [ "There are many tools that have been used historically. The people using them are called surveyors.\n\nThere's one called a level that can be used to find the elevation of terrain. There's a theodolite that is used to measure vertical and horizont...
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7bmyh9
why do we celebrate someone’s birthday? why do we celebrate the day someone was born?
explainlikeimfive
https://www.reddit.com/r/explainlikeimfive/comments/7bmyh9/eli5_why_do_we_celebrate_someones_birthday_why_do/
{ "a_id": [ "dpj6wzp" ], "score": [ 3 ], "text": [ "Essentially, when we celebrate a birthday, we're saying, \"we really value you as a person, so much in fact, that we've decided to hold a celebration honoring the day you were born.\" It's also nice to make someone feel special every now and then...
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4wn5az
why is it that humans have no knowledge of reproduction at birth, while most animals have it hardwired into their genetics?
explainlikeimfive
https://www.reddit.com/r/explainlikeimfive/comments/4wn5az/eli5_why_is_it_that_humans_have_no_knowledge_of/
{ "a_id": [ "d68byxp", "d68c05z", "d68ee30", "d68frsf", "d68gfoj", "d68o2c6", "d6926f2" ], "score": [ 56, 12, 20, 3, 6, 6, 9 ], "text": [ "Humans also have it hard wired into their genetics. The programming just doesn't seem to turn on until puberty....
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a1dyjx
what exactly is a bayou, and what makes it different than a creek or a swampy area?
I live in central NJ and there’s a muddy creek in the nearby woods; is that a bayou? Or would it only be a bayou if it was in Louisiana?
explainlikeimfive
https://www.reddit.com/r/explainlikeimfive/comments/a1dyjx/eli5_what_exactly_is_a_bayou_and_what_makes_it/
{ "a_id": [ "eaoztgm", "eap8yhm" ], "score": [ 4, 3 ], "text": [ "A swamp is a piece of wet, spongy land; low ground saturated with water; soft, wet ground which may have a growth of certain kinds of trees, but is unfit for agricultural or pastoral purposes while bayou is a slow-moving, of...
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