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32wvn8 | what's the difference between a forest and a wood? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/32wvn8/eli5_whats_the_difference_between_a_forest_and_a/ | {
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"They're used interchangeably a lot. You'll get different answers from different resources, but the general consensus seems to be that woods are smaller than forests.\n\n > A wood is an area covered in trees, larger than a grove or a copse. A forest is also an area covered in trees, but it is larger than a wood\n\n > The U.S. National Vegetation Classification system differentiates them according to their densities: 25 to 60 percent of a a wood is covered by tree canopies, while 60 to 100 percent of a forest is canopied."
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1yc9zg | Are there any good source material on the Warsaw Ghetto to be had online? | Hi guys, I have a project I'm working on which requires unbiased primary sources on the Warsaw ghetto (demographics, population density, supplies, mortality rates, etc.). I've been scouring the net and my library for information about it, but I mostly seem to find holocaust denialist websites and websites referring to a book I can attain within my timeframe whilst providing incomplete information.
I'd really appreciate it, thanks!
Alternatively: Are there any better subreddits where I could ask for help? I figure I'll post this to /r/favors and /r/ask, but if there are any other good subs for this kind of stuff I'd appreciate you mentioning them.
Cheers! | AskHistorians | http://www.reddit.com/r/AskHistorians/comments/1yc9zg/are_there_any_good_source_material_on_the_warsaw/ | {
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"Many of the relevant primary sources wont contain the those specific details in an aggregated way. There are a few great examples of diaries and reports coming from the Warsaw Ghetto. The statistics you are looking for would likely come from secondary sources.\n\nOne great example is the Stroop Report. This is written by a commander (Stroop) and it documents the suppression of the uprising. I've included a link to the National Archive where you can get the the full report [here](_URL_1_). This document was used in the Nuremberg Trials.\n\nI would recommend you check out the [Yad Vashem site](_URL_2_). That is the Holocaust Museum in Israel. They have spent a lot of time collecting primary sources, photos, personal accounts etc, about the Holocaust of the Jews (Shoah). I've linked to the overview of the Warsaw Ghetto, but check out the digital collection at the top.\n\nA last little tip is diaries of the time. I don't know where you're located, or which libraries you have access to but here are a few WorldCat records for some notable ones: [The Warsaw diary of Adam Czerniakow](_URL_0_) and [Scroll of agony, the Warsaw diary of Chaim A. Kaplan](_URL_3_).\n\nHope this help.\n\nSource: I'm an academic reference librarian and Jewish history specialist"
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elzx1n | we do we instinctively grab a part of our body after it is hurt? | I just tweaked my wrist and my immediate reaction was to grasp it. I have no idea if grabbing it actually does anything, but it seems to be a natural reaction for most people when a body part hurts. Why is that? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/elzx1n/eli5_we_do_we_instinctively_grab_a_part_of_our/ | {
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"A) instinct. To protect it from further damage (if the damaging agent is ongoing) or to prevent bleeding and such.\n\nB) pain. Our brain knows that pressure sensation blocks pain sensation from experience. So we reflexively grab the injury site because it alleviates the pain.\n\nEdit: English and clarity",
"So you have 2 different types of pressure sensors in your skin, superficial or closer to the surface and deep. Pressure sensors report back to the brain faster than pain sensors do so you can \"jam the signal\" ish by applying pressure. Say you put your hand on a hot burner, the spine has limited commands it can give to the body in case the brain can't give commands (see stroke victims) or to protect the body from further damage. This means that the pain signal follows tracks of nerve impulses to the spine where a quick response is sent back while a detailed report of the pain is sent to the sensory part of the brain for further analysis. The brain follows up the damage report by checking sensation, applying pressure or grabbing the area. Typically you also visually check it as well to see how the skin in the area is doing."
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1j7pwx | Following the passing of the Thirteenth Amendment, were there any cases of slave-owners attempting to continue the practice illegally? | I'm curious as to whether there were any remote corners of The South where slaveowners evaded the government and continued to hold slaves for a few months or even years after the Thirteenth Amendment was passed. Black workers were still treated terribly of course, and human trafficking via criminal organisations persists, but were there any cases of land-owners or rich households refusing to let go of their "possessions", so to speak? | AskHistorians | http://www.reddit.com/r/AskHistorians/comments/1j7pwx/following_the_passing_of_the_thirteenth_amendment/ | {
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"All across the South during the years following the civil war, a series of \"Black codes\" were passed into law. Their purpose was to effectively re-enslave the freed slaves by justifying their forced labor by labeling them vagrants, essentially making unemployment illegal and thereby allowing a state to force a former slave to work by arresting them and then using them as convict labor.\n\nSometimes, the black codes were simply pre-civil war slave laws with the word \"slave\" replaced with \"negro.\"",
"It was less a few dark corners, and more a concerted effort by large swathes of society, who attempted to keep slavery alive in all but name. Here is the Fourth Circuit discussing some of this history:\n\n > The South was far from wholly reconciled to the abandonment of the system of forced labor that contributed significantly to the economic success of its agriculture. *See* [R. Fogel and S. Engerman, *Time on the Cross* (1974)](_URL_1_). Many planters felt strongly that they simply could not work their fields without compulsory service. *A Georgia Leader on Reconstruction and Conversation of Alabama Planters* in *R.N. Current, ed., Reconstruction [1865-1877]*, at 39, 46 (1969). Moreover, the war-torn South had large numbers of homeless uprooted people who today would probably be characterized as refugees but were then commonly seen as roaming, \"dangerous\" vagrants.\n\n > Some local authorities responded by permitting employers to engage laborers on a basis that essentially bound the worker for life. [C. V. Woodward, *The Strange Career of Jim Crow* 23 (3d Rev.Ed.1974)](_URL_6_). Many states enacted so-called \"Black Codes\" that severely restricted the freedom of the former slaves and provided tough criminal sanctions for those who violated their \"labor contracts\" with employers. [J. H. Franklin, *Reconstruction After the Civil War* 48-50 (1961)](_URL_4_); [J. L. Roark, *Masters Without Slaves* 139-40 (1977)](_URL_3_).\n\n > ...\n\n > In [*Bailey v. Alabama*, 219 U.S. 219 (1911)](_URL_7_), the Supreme Court held invalid an Alabama statute that prescribed criminal penalties for laborers who breached their employment contracts without satisfying debts owed their employer. The statute established a presumption of criminal intent to defraud the employer by the fact of the mere breach of the contract. The Court ruled that the statute effectively required compulsory service impermissible under the thirteenth amendment because the compulsion inherent in the threat of criminal sanctions was as strong as that inherent in the use of physical force.\n\n > In [*United States v. McClellan*, 127 F. 971 (_URL_0_.1904)](_URL_2_), the district court refused to quash an indictment that charged several defendants with the sale of a man into forced labor, holding that the [federal statutes] broadly regulated behavior of this type and were neither unconstitutional nor were to be confined to the narrow circumstances of the particular evils which they were intended to redress.\n\n[*United States v. Booker*, 655 F. 2d 562 (4th Cir. 1981)](_URL_5_) (some citations omitted and some spacing added).",
"PBS produced a beautiful documentary on exactly this subject: [Slavery by another name](_URL_0_)\n > Directed by Sam Pollard, produced by Catherine Allan and Douglas Blackmon, written by Sheila Curran Bernard, the tpt National Productions project is based on the 2009 Pulitzer Prize-winning book by Blackmon. Slavery by Another Name challenges one of our country’s most cherished assumptions: the belief that slavery ended with Abraham Lincoln’s Emancipation Proclamation of 1863. The documentary recounts how in the years following the Civil War, insidious new forms of forced labor emerged in the American South, keeping hundreds of thousands of African Americans in bondage, trapping them in a brutal system that would persist until the onset of World War II.\n\n > Based on Blackmon’s research, Slavery by Another Name spans eight decades, from 1865 to 1945, revealing the interlocking forces in both the South and the North that enabled this “neoslavery” to begin and persist. Using archival photographs and dramatic re-enactments filmed on location in Alabama and Georgia, it tells the forgotten stories of both victims and perpetrators of neoslavery and includes interviews with their descendants living today. The program also features interviews with Douglas Blackmon and with leading scholars of this period.\n \n"
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3qr7uu | In medieval and pre-modern times, political entities made marriage pacts between heirs in order to secure peace. Often times, this didn't last for more than 20 years, if not even less. Why did they even bother? | this peace didn't last*... | AskHistorians | https://www.reddit.com/r/AskHistorians/comments/3qr7uu/in_medieval_and_premodern_times_political/ | {
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"Twenty years of peace is much better than no peace at all. Twenty years is enough time for a generation of young men to forgo military service, time to build infrastructure, time to consolidate power, and time grow a treasury.\n\nThere are also plenty of examples of peaces that last longer than twenty years, or even result in permanent peace and consolidation. The nation of Spain was formed from [the union of the Kingdom of Castile and the Kingdom of Aragon](_URL_0_), a union that was set in motion when Isabella of Castile, the future queen, married Ferdinand the Catholic, a future king of Aragon. Their grandson Charles V and great grandson Phillip II would later become kings of a united Spain. James the VI of Scotland similarly oversaw the personal union of England and Scotland when he inherited the crown of England, becoming James I, in 1603. England and Scotland would later formally join together to become the Kingdom of Great Britain in 1707.\n\nYour question also implies that it is particularly unusual for a peace treaty to last less than twenty years. There are numerous examples of more modern treaties that did not maintain peace for much longer than twenty years. There were only twenty-one years between the World Wars (1918 to 1939) and only twelve years between the Gulf War (ended 1991) and the Iraq War (began 2003).\n\nI can try to include better sources if asked, but I don't think anything I've said here is controversial. "
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fvbxhi | What happened to German and Italian volunteers in the International Brigades of the Spanish Civil War after they were disbanded in 1938? | AskHistorians | https://www.reddit.com/r/AskHistorians/comments/fvbxhi/what_happened_to_german_and_italian_volunteers_in/ | {
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"I gave a relatively brief answer to this [here](_URL_0_), focusing more on the Germans (for whom I had a relevant source handy). If I get the chance later today, I'll try and expand on it!"
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31qce9 | What (if anything) did Native Americans think lay beyond the Pacific and Atlantic oceans? | Were there any religious or cultural assumptions about it being the edge of the world? Was there any speculation about there being other continents and civilizations? Mostly thinking of North America but if Central and South Americans had any ideas then I'd be interested to hear those too. | AskHistorians | http://www.reddit.com/r/AskHistorians/comments/31qce9/what_if_anything_did_native_americans_think_lay/ | {
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"The desert people of the American Southwest generally understood the concept of oceans as not being fundamentally different from a large lake or stream. Among the [recorded] creation myths of the O'odham peoples, at least two contain gods or demigods turning small rivers into vast oceans, splitting apart the original peoples of the Earth, although the survival of remote peoples is left ambiguous. One of these stories later goes on to discuss the people who survived the flood on the other side of the ocean, who were conveniently white-skinned. Another passage from the same source states that another group of people over the ocean were in fact dark brown. Both of these groups were the result of mistakes in creation, after which the perfectly colored Hohokam groups were created. As prophetic as these may sound, our one source of these tales was recorded from a drunkard by a priest in the 1930s. Given that it is the only semi-complete history of the O'odham remaining today, we have no means to determine how far back the individual elements go. \n\nAmong the Hopi and other Puebloan peoples, we have an understanding that the oceans were not the complete end of land. At the very least they understood that people lived in the islands off the Atlantic and Pacific coasts from trade with groups living nearer to the sea. \n\nBoth groups had an accurate understanding of the geography of their continent between the oceans and an understanding that humans could live on the water as their neighbors did. It's not impossible that they conceived of other lands similar to their own across the water, which was understood to be similar to a large river or lake. The stories we have hint at this understanding, but the near-complete absence of historical records about the O'odham and Yuman people make that suggestion speculative at best. The situation among the Puebloans is little better. While they clearly understood the concept of sailing quite well, the myths make scarce mention of foreign lands that would not have been visible from shore.\n\nBahr, Donald M., et al. *The short, swift time of gods on earth: The Hohokam chronicles.* Univ of California Press, 1994.\n\nCourlander, Harold, ed. *The fourth world of the Hopis.* UNM Press, 1971.\n\n"
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11j8u0 | Is it possible that in the distant future, an organism that exists right now on Earth, will evolve to the point that it can be considered intelligent life? Which animal comes the closest? | askscience | http://www.reddit.com/r/askscience/comments/11j8u0/is_it_possible_that_in_the_distant_future_an/ | {
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" > Is it possible that in the distant future, an organism that exists right now on Earth, will evolve to the point that it can be considered intelligent life?\n\nYes, it's possible, but by no means is it a sure thing. Evolution doesn't have a goal in mind, nor does it have specific end points that are inherently better than others. Evolution adapts to the environment, and what works works, what doesn't dies off.\n > Which animal comes the closest?\n\nWe have a difficult time defining intelligence *within our own species*. The difficulty goes up astronomically when you look at other species.\n\nAre you talking about technic intelligence? It's unlikely anything in the ocean will ever develop technology (at least, as far as we can tell - without fire lots of tools are going to be difficult to make).\n\nSocial intelligence? Well, insects seem to have a big advantage there... but they're probably a ways off on the tool front.\n\netc, etc, etc.\n\n\nYou see the difficulties? ",
"Evolution is not directed.\n\nWe can't answer this without speculation."
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1qfda2 | How much can you learn from someone's genome? | I've heard you can learn id someone by looking at their DNA, but what else can you learn if you know what to look for? | askscience | http://www.reddit.com/r/askscience/comments/1qfda2/how_much_can_you_learn_from_someones_genome/ | {
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"Well this is fun, we literally just covered this kind of stuff in my advanced molecular biology course.\n\nYour genome will contain variation depending on genetics that has been passed down from your parents. You may be homozygous for 11 copies of a short-tandem repeat (STR, 2-3 'letters' repeated over and over again in the sequence) where I will be heterozygous for 13 and 8 copies. Your \"DNA fingerprint\" that the FBI uses involves these regions, when the areas that contain them are amplified by PCR, they show up as different lengths.\n\nFurthermore, there are single-nucleotide-polymorphisms (SNPs) where you may have an A where I have a C (or C-A or T-G or T-A...you get the point). There are also \"indels\" - insersions or deletions relative to one genomre or another. These can serve as markers for disease or other traits, especially if they occur in protein coding genes. There are a very very large number of these variations, and I could predict (not even close to 100% certainty, though) some traits about you as well as heritable diseases you may carry. The debate on nature/nurture is how certain could I be given your genotype?\n\n[This database](_URL_0_) is called Online Mendellian Inheritance in Man and catalogs diseases/traits and contains a *wealth* of SNP and indel data about them. Doing some mining, you can find tables like [these](_URL_1_) that will list all known variants for a gene and link to more information about them. This example is the Von Willebrands Factor, mutations of which cause Von Willebrands Disease which is a mild bleeding disorder. I don't know your background, but this site contains a lot of very technical information.\n\nYou may have heard of [23andMe](_URL_2_) which is a commercial service that will assay your genome for specific markers as well.\n\nEDIT: If your family has submitted their genomes to a database as well, we could ID them as well"
]
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3s6g1h | why are hispanics included as whites in statistical polls instead of being considered their own independent demographic like blacks or native americans? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/3s6g1h/eli5_why_are_hispanics_included_as_whites_in/ | {
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"Hispanic is not a race. It's an ethnicity. There are white Hispanics, black Hispanics, Native American Hispanics, and even Asian Hispanics.\n\n",
"White is an ever shifting definition. It wasn't that long ago that Irish, Italians, Eastern Europeans and Jews weren't considered white.",
"Nothing about racial categories makes sense, and that's because race is a social, not biological construct.",
"Latinos/Hispanics (technically different but let's stay out of the weeds for this) are a label applied to a group that look incredibly different because it's defined as being descended from a Spanish speaking country, countries that aren't necessarily near or historically like each other.\n\nPeople from the Dominican Republic and Mexico tend to look very different for instance. Cameron Diaz, Jessica Alba, Rosario Dawson and Zoe Saldana are all Latina actresses, yet look different. Diaz has pale skin with blue eyes while Zoe Saldana would be classified as black by pretty much everyone in the U.S. despite being Puerto Rican. So, technically, the \"white\" Cameron Diaz and the \"black\" Zoe Saldana are the same ethnicity.\n\nThis is because the concept of people descended fromspanish-speaking places being the same group was made up [very recently](_URL_0_). \"Hispanic\" wasn't on U.S. forms until the 70s. The 1970s. That recently in the past.\n\nBasically, \"Hispanics\" are the group that really show just how silly the idea of race/ethnicity is. It's completely made up and it happened so recently we have documents that prove it. Yet, for some reason, we forget about this when talking about other groups who happen to have a longer history of being labeled as a group.",
"What if you thought of everyone from English speaking countries as a group...let's say Hugh Jackman, Bob Marley, and Narendra ModI (Prime Minister of India)...you could say that they're all Anglos...but they're not the same race.",
"You'll never get the right answer for this, because apparently there isn't one. There's always conflicts between who is and who isn't Latino. Also the word Hispanic gets a lot of incorrect definitions",
"You seem to be misunderstanding how the US Census Hispanic and White categories work. Have a look at [the race and ethnicity questions in the US Census](_URL_5_). You'll note that they ask two independent questions of each person that is reported in the form:\n\n* Is this person of Hispanic, Latino, or Spanish origin?\n* What is this person's race?\n\nThe first is a yes/no question, but the \"Yes\" options include choices for various Hispanic nationality groups (Mexican, Puerto Rican, Cuban, write-in). The second is a multiple-choice question—you can pick more than one choice—and also has a write-in option. People can fill in any combination of answers to those two questions, and the statistics count all the combinations. \n\nSo you can answer \"Yes\" to the Hispanic question and \"White\" to the race question—or \"Yes\" to Hispanic and \"Black\" to race, \"Yes/Native American,\" \"Yes/Asian,\" \"Yes/White+Black,\" etc. And none of those is an unusual answer! Watch these videos to understand why:\n\n* _URL_1_\n* _URL_3_\n* _URL_6_\n* _URL_0_\n* _URL_7_\n* _URL_4_\n* _URL_2_\n",
"Hispanic = from a Spanish speaking country. There are white, black, asian, and native peoples who originate from the many spanish speaking countries. ",
"Can someone help me out here. So all 4 of my grandparents were born in mexico. My maternal grandmother definitely had indigenous blood in her which was evident when you saw her. Same for my grandfather. I think my paternal grandmother might have been half german. My ethnicity is hispanic, but what would be my race? I always check the \"other\" box on documents and write mexican american. I don't look white, black, or native american. I look mexican. Wtf is my race?",
"Historically blacks and Hispanics follow the one-drop rule i.e if you have a drop of black blood you are black, a drop of Hispanic blood and you are Hispanic. The Hispanic race is from Spain a subset of white people, many Hispanics are mixed with Native American people. Objectively the classifications don't really make any sense.",
"as a person not from the US I was initially baffled that you guys didn't consider hispanics white",
"So that \"white\" can continue being the majority. Nothing like changing socially constructed definitions so you can keep oppressing people. ",
"What exactly is \"Hispanic\" and do Americans consider Spanish people to be non-white?",
"Former Census worker and anthropology geek here. Hispanic is NOT a race like white, black, Asian, etc.. It is a cultural definition. You can be a Hispanic and be of any race. The majority of Hispanics are mixed race anyways. Also, a large number of Hispanics consider themselves white and put that as their race on the Census.",
"I live in a country where race and ethnicity isn't registered anywhere.\n\nIs there any discussion about just do away with this categorization completely in the US? It's seems to be mostly confusing."
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"https://www.youtube.com/watch?v=eIXNwj8biHY",
"https://www.youtube.com/watch?v=Bt__QuCmBEw",
"http://www.prb.org/Publications/Articles/2009/questionnaire.aspx",
"https://www.youtube.com/watch?v=NBaPG14cdkM",
"https://www.youtube.com/watch?v=SdbEMBmzo2U"
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3lv8jv | what causes "flashing lights", or blurry vision after strenuous physical activity? | Had this happen to my younger brother. My parents are convinced he has a concussion and are having him see multiple doctors and are preventing him from doing any physical activity until further notice, as well as most-likely inhibiting him from joining the wrestling team for his high school. I don't want this to happen.
He had no significant amount of water before an hour workout that included 10 minutes of jump roping followed by 50 minutes of lifting.
My brother claims to have seen flashing lights after he stood up from a 10 minute car ride home.
| explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/3lv8jv/eli5_what_causes_flashing_lights_or_blurry_vision/ | {
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"**NOTE**: I am not a medical doctor, and this is not a diagnosis; just the best attempt I can at explaining it.\n\nIt's likely caused by the gel inside of his eyes rubbing on or pulling at the retina. If he stood up after a car ride, it can cause a change in blood pressure as well, which would lead to less oxygen going to the brain and some experience flashes of light along with a narrowing of the field of vision."
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1rwxa7 | if an ambulance on its way to a call witnesses an accident, what do they do? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1rwxa7/eli5_if_an_ambulance_on_its_way_to_a_call/ | {
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"It depends on the severity of the accident compared to the severity of the call they're en route to. If they see a horrible car wreck, and they're on a call for a broken bone, they'll stop for the wreck and radio in to let the dispatcher know to send out a new ambulance for the initial call. However, if they were on their way to a heart attack victim, they'll likely radio in and request a new ambulance for the wreck.",
"Paramedic here.\n\nWe stop, have a short look and call dispatch. Ultimately, until we reach the patient it's their call so they set the priorities in such a situation."
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272ed8 | how do i know that i don't have depth perception? | Could I lack depth perception and just not know it? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/272ed8/eli5_how_do_i_know_that_i_dont_have_depth/ | {
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"Sure, if you've never experienced true binocularity (brain fusing each eye's image into one that is 3D), you might not realize you don't have it. It's possible to develop that skill so long as both eyes are physically intact and functional and so is your brain. Neuroscience ftw!\n\n A book that discusses this is \"Stereo Sue\" by Sue Barry about a lady scientist who didn't realize that very thing she was in her 50s and was able to regain it. It's an interesting story! "
]
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|
8oarq7 | since oil & water don't mix, how are essential oil soaks helpful? | Doesn't the oil just sit on the surface, like it looks, reaching the intended body parts only in the small area that intersects with the top of the water? Or does it slowly mix with the water? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/8oarq7/eli5_since_oil_water_dont_mix_how_are_essential/ | {
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"As far as I know there is no scientific proof that essential oils work anyway, but yes your skin can only absorb so much.",
"Essential oils are worthless for everything but smelling good anyway, so adding water certainly doesn't improve anything"
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75t27i | if a nuclear bomb is dropped on other nuclear bombs that are idle on the ground, will it create a double explosion or do these weapons need to become 'activated' in order for them to be able to detonate? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/75t27i/eli5_if_a_nuclear_bomb_is_dropped_on_other/ | {
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"a nuclear device functions by joining two or more chunks of radioactive material with explosive force together attaining a critical sustainable mass. A nuke dropped on nukes would not trigger this....the grounded nukes could only, theoretically, add to the radioactive fallout as their unspent nuclear material is scattered about \n\nPs your premise is a bit flawed as MOST nukes are detonated ABOVE a target, not on impact with it. ",
"Nuclear bombs need to be set off in a controlled way in order to explode in the massive yield they normally would. However they contain conventional explosives which would certainly spread radioactive material around. But if you are setting them off with a nuke that won't be a big impact.",
"In any design that's actually been built the nuclear bomb can't be detonated externally, they must be triggered through a very specific and carefully timed sequence of events.\n\nBombing them would just damage them and possibly scatter radioactive material.",
"Depends on a lot of things.\n\nNuclear bombs work by changing the critical mass of the nuclear fuel. \"Critical mass\" is the amount of nuclear material you need to have a sustained nuclear reaction. You can artificially make a smaller-than-critical mass into a critical mass in several ways. One way is to cover it with a material that reflects neutrons (which would cause all the neutrons that would've escaped outwards from the material to reflect back inwards, generally used in nuclear reactors and research), but another way is to change the temperature and pressure of the material (which is done in nuclear weapons by using \"explosive lenses\" which is a fancy way of saying you surround it with conventional explosives).\n\nWithout those explosives going off (and a few other things I'd guess) that nuclear weapon isn't actually fissile (able to undergo fission). A nuclear explosion above the silo where the bombs are stored is just as likely to vaporize the exposive as anything else, not to mention that unless that explosion is able to actually trigger the explosive correctly it's not going to explode. (C4 and TNT for example are completely safe to burn, and only explode with specific stimulii.)\n\n",
"Detonating a nuclear bomb is a very precise process, a lot of complicated things have to happen in just the right order. Even the most primitive bombs would be unlikely to go off in a high order explosion just because of a nearby explosion, nuclear or not. Modern nuclear weapons are actually deliberately designed so this is impossible, as a safety measure.",
"Nuclear weapons are conceptually simple, you smash together enough U-235 (a 'supercritical mass') and it goes boom. The hard part is making it go boom when you want it to, and NOT melt when it's sitting in a silo.\n\nThere are two kinds of 'explosions' that occur in a nuclear weapon. The most obvious one is the nuclear fission chain reaction that makes a nuke what it is, which I'll call 'nuclear detonation'. The second kind of explosion (technically the first to happen) is what I'll call a 'primary detonation', which is a bunch of high explosives rigged precisely to trigger or 'ignite' the big boom.\n\nThere are two main ways in which these parts are put together, the 'Gun' and the 'implosion' methods. In the gun device, a big slug of U-235 is shot at high speed into another mass of U-235 that fits it like a glove, bringing together a supercritical mass. This device was constructed during the Manhattan Project by essentially strapping a bunch of expensive equipment and U-235 to an artillery piece and firing it. The second method uses a hollow sphere (also known as a pit) made of Uranium. In its hollow shape, the mass is not supercritical, but when it is compressed by the primary detonation into a solid ball, the mass becomes supercritical. It's a lot like crushing a soda can, but your hands are TNT and the soda can is going to blow your block party off the map.\n\nIn both methods of detonation, the critical mass must be brought together very quickly and very precisely. Otherwise, instead of the desired nuclear ignition, a 'premature detonation' will occur, severely reducing the weapon's power (loads better for the world than premature ejaculation ;). \n\nSo, to answer the question, if a nuclear warhead were dropped on a warehouse full of nukes, it would NOT cause nuclear detonations in the other weapons. It would, however, cause lots of bad shit, including:\n\n-Big Boom from the original warhead\n\n-All of the nuclear materials in the bombs is now volatile nuclear waste that may be in various states of criticality and may or may not fissioning and creating more hazardous waste. To get an idea of what this could develop into in the worst case scenario, read up on the elephant's foot at Chernobyl. Its not exactly the same situation, but Chernobyl gives us an idea of how difficult it is to move and protect ourselves from uncontained fission materials.\n\n-Detonation of high explosives from primary detonation systems of other bombs. This is unlikely to cause any nuclear detonations because the precision of the detonation is completely overwhelmed by the initial warhead, but explosives are explosives. TBH the size of these explosions is nothing compared to the initial weapon's power, and amounts to something like a mosquito bite on an arm that a bear just tore off of you.\n\n-WWIII (Assuming some head-ass didn't bomb their own country, which almost happened once in North Carolina I think)\n\n\nTL;DR: No, it won't cause a 'Double Explosion', but it's still a nuke, and it's gonna kill the heck out of you.\n\n\nSide note: For similar reasons, nuking or crashing a plane into a nuclear power plant does not cause a nuclear detonation. Nuclear weapons are devices carefully orchestrated and calibrated to 'make the stars align' so to speak, and create the very narrow conditions that make a nuclear explosion possible. On the other hand, a power plant is designed to generate electricity in a sustained and controlled fashion, which inherently precludes the possibility of a nuclear detonation, simply because the specifications on how to trigger a nuclear detonation are so tight."
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7wy34p | why do bottles of liquid have a dent/semi circle at the bottom of them? | My brother told me a while ago that it prevents it from exploding or something. Is there an act | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/7wy34p/eli5_why_do_bottles_of_liquid_have_a_dentsemi/ | {
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"Its to make the plastic stronger. Without it they would have to add much more plastic to make it stable, which is more expensive. The bottle wouldn't explode, but it would cause the thinner areas to sag and deform. That would increase the chance of it bursting apart when force is applied. But with the divot, that sort of outcome is essentially impossible.",
"It can be for strength, if the contents are under pressure, or it can just be so it will sit flat on a surface without rocking. You could in theory do that with a perfectly flat bottom, but that requires more precise and expensive molds(have to account for distortion as it cools too). Or it can be to make the bottle look bigger, compared to its volume. \n\n",
"If you had a flat bottom it would simply bulge out. Now you would have a shitty bottle that can't stand. The dome simply distributes the forces evenly to the outside ring of the dome. It's the outside ring that has a bit more ridigity that prevents that from deforming.\n\nI suggest you look up the making and design of a soda can on YouTube. It explains the engineering behind it. Pretty cool stuff. ",
"The dent and curved rim on the bottom of a can gives it the strength to be stacked on without bursting",
"I can't speak much for glass bottles, but plastic bottles and aluminum cans have these features so that if they freeze, the plastic will bulge out and pop into a new position that gives the liquid more free volume to occupy. This prevents a sticky mess on the consumer's garage floor"
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5by6yg | the dow futures is reported to have dropped 700 points already. what does that mean for retirement funds, the market in general, etc...? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5by6yg/eli5_the_dow_futures_is_reported_to_have_dropped/ | {
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"It means that Mr. Market is scared, and the future looks really bleak. \n\nThe market believes a recession or worse is coming and that for the foreseeable future, things in an economic sense look bad. \n\nRetirement funds are based heavily on the stock market (not entirely) which will go down correspondingly. However, they are also based to some degree on bonds, which generally go up when stocks go down. \n\nGenerally....\n\nThe thing is, no one really truly knows the answer. And if they did, they could use that knowledge to make money. \n\nWhat it means for you and for me is that most experts foresee bad things happening. ",
"What u/Chumkil said but it is unlikely to be a long-lasting drop, the underlying economy is strong and, once the excitement has died down, the markets will return to their original state - i.e. rising.\n\nThe BBC were talking about this yesterday, apparently these flash-crashes are more to do with computer algorithm trading more than human sentiment. Their analyst's advice to investors was \"play the long game and sit tight, use any significant drop to expand your portfolio.\"",
"What I don't understand is how the market is falling, when markets have been closed since 4:00pm EST and the first polls don't close until 7....I mean I can see how people will forecast the drop tonight, but wouldn't the market have to open in the morning to actually drop?"
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1nfs65 | During the Cold War period, was Able Archer and The Cuban Missle Crisis the peak of tensions? | Were there any events that normal citizens wouldn't know about that would be even more tense than those moments? | AskHistorians | http://www.reddit.com/r/AskHistorians/comments/1nfs65/during_the_cold_war_period_was_able_archer_and/ | {
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"I would see a distinct difference between \"peak of tensions\" and \"closest we came to a nuclear exchange.\" The Berlin crisis of 1948 was potentially a higher \"peak of tensions\" than Able Archer 83, but because the nuclear situation was only one-sided, it is not cited as a \"close call.\" I would not consider Able Archer 83 a \"peak of tensions,\" as it was primarily one-sided, though it was definitely one of the top \"close calls.\" (What made it so dangerous was that the USA/NATO was so utterly unaware of how tense the Soviets felt about it.) \n\nSimilarly, there were other \"close calls\" that were not marked by \"peaks of tensions\" — such as the numerous \"false alarm\" scares that the US and USSR both suffered from errors in their early warning systems. \n\nI would disentangle these two categories. What makes the Cuban Missile Crisis so remarkable and interesting is that it is the rare confluence of the two — a peak of tension _and_ a close call. There were many other very tense moments that were not close calls, and many close calls that were not actually peaks of tensions."
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3cnjdg | what's in artificial food coloring that makes it so toxic to consume? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/3cnjdg/eli5_whats_in_artificial_food_coloring_that_makes/ | {
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"Food coloring is not considered toxic by most people. From Google:\n\n > \n > \n > While red dye #2 was subsequently banned from products sold in the United States, many health-conscious consumers continue to avoid foods with other artificial colors or dyes — **even though the U.S. Food and Drug Administration (FDA) still considers them safe for human consumption**.\n\n\n\nBut that doesn't even tell the full story. \n\nRed Dye #2 might have never been particularly unsafe to humans. \n\n > \n > \n > In 1976, the Food and Drug Administration (FDA) concluded that, in high doses, Red No. 2 could cause cancer in female rats. The FDA declared it an ingredient non grata in the United States because **although it had never been shown to pose health risks to humans, no one had been able to prove it safe, either**.\n\nBut the media painted a scary picture of Red Dye #2.\n\n > \n > \n > In 1971, however, Soviet scientists announced that Red No. 2 caused cancer. Public outcry in the U.S. against the dye quickly gained such fervor that the Mars candy company temporarily stopped producing red M & Ms despite the fact that they had never contained Red No. 2 in the first place.\n\n\nRed dye #2 was replaced in America by Red Dye #40, but #2 is still available and considered safe in Europe where one last bizarre fact enters the picture:\n\n > \n > \n > But in a twist of fate, the European Food Safety Authority recently recommended limiting children's intake of Red No. 40. As a result, while Red No. 2 is illegal in the U.S. but flows freely in the EU, the near-opposite is true for Red No. 40.\n\n\nYou can read more about it [here](_URL_0_)."
]
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65gxj9 | why does it feel like your stomach drops when your adrenaline kicks in? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/65gxj9/eli5_why_does_it_feel_like_your_stomach_drops/ | {
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"It's related to the fight-or-flight response. Your body prioritizes your extremities and blood is drawn away from \"non-essentials\" such as the digestive system. This leads to that uneasy stomach feeling you get."
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||
33eu1y | what happens to someone convicted of a felony that is going to die soon? | I'm curious to know, if someone is convicted of a felony and found guilty but is going to die soon, how does the justice system deal with it? I'm thinking of something like a person whom has cancer or some other non-contagious illness that will lead to their death in a foreseeable amount of time. Are there special prisons or something?
Mostly wondering because I've been binge watching cop shows... | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/33eu1y/eli5_what_happens_to_someone_convicted_of_a/ | {
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"There are Hospitals/infirmaries in prisons. They'd likely just spend their final time in there.\n\nOr they might just be put in with the general population if they don't need constant medical care.",
"They still go to prison, there was a nazi war criminal/guard recently convicted about a year or so ago. At 90 they shipped him off to Germany to be incarcerated",
"If they were convicted when already suffering from the disease, they would likely be held in prison as normal, and provided medical care for the rest of their natural life.\n\nThere's also a thing called compassionate release, where a prisoner that develops a terminal illness while in prison will be released, essentially to die with their family. Most states, and the federal government have some kind of program like this, though the number of people released under those programs is still pretty small."
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3imr6u | Why can a person safely receive platelets donated by anyone, but can only receive a particular type of whole blood? | askscience | https://www.reddit.com/r/askscience/comments/3imr6u/why_can_a_person_safely_receive_platelets_donated/ | {
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"Platelets don't have antigens (the things antibodies recognize) on them. What might be a good way to remember this is that they're not made from red blood cells where the ABO blood group antigens are, they're shed from cells in the bone marrow called megakaryocytes. \n\nThat's not to say platelets are JUST floating bits of cytoplasm. They've got glycoproteins on the outside to recognize various signals that, if received, may then induce them to release granules filled with clotting factors.\n\nBut why don't people have antibodies to these glycoproteins? People have antibodies against certain glycoproteins on red blood cells, right? Yes, they do. However, basically EVERYONE has the same platelet glycoproteins. Developing an immune reaction against them would almost certainly mean death. Super bad thrombocytopenia (low platelets) AND what's basically a bad transfusion reaction, which can kill a person in minutes.\n\nThat being said, there are bleeding disorders where people lack some of these platelet factors (von Willebrand disease, for example). That's different from their bodies actively attacking any cell that has them, and they have problems with clotting and blood vessel damage, for the most part."
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41k6y7 | why don't people get tolerance from orgasms like they do from drugs? | [deleted] | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/41k6y7/eli5_why_dont_people_get_tolerance_from_orgasms/ | {
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"Well you can. Masturbate everyday, and compare it to not masturbating for a month. You do build up a tolerance if you will. It's less intense.",
"I can confirm this too, from exhaustive experimenting. Then more frequent you repeat it, the smaller a kick you get."
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230tie | Is the shield wall fighting depicted on the show "Vikings" historically accurate? | It seems like they have made an effort to depict something other than usual hollywood 1v1 fighting but is it accurate for the times with them pushing as a group and occasionally creating gaps for people behind to stab/shoot? | AskHistorians | http://www.reddit.com/r/AskHistorians/comments/230tie/is_the_shield_wall_fighting_depicted_on_the_show/ | {
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"Awesome thank you. I checked the FAQ and totally missed it."
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|
db5xd6 | what is the difference between inches, millimeters and caliber when talking about guns? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/db5xd6/eli5_what_is_the_difference_between_inches/ | {
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"Caliber is a measure of the internal diameter of a gun barrel. Inches are an SAE unit, and millimeters are a metric unit. Either can be used to describe the caliber, based on the manufacturer's preference.",
"Oh boy, this one is a rabbit hole because there's no real standards and *a lot* of marketing nonsense.\n\nFirst, the basics: When a firearm is described as \"thirty caliber\" (.30) that means that the internal diameter of the barrel is .3 inches. Since the late 1800s most of the world outside of the UK and USA has used metric measurements (millimeters) for the same thing. So a gun that is \"nine millimeter\" (9mm) has a barrel with an internal diameter of 9mm.\n\nNow comes the confusing stuff, because there is another set of important measurements, cartridge length. For example, the most common 9mm cartridge is 9x19mm, and it is 9mm wide and 19mm long. It is commonly known as 9mm Parabellum or 9mm Luger. It is not interchangeable with 9x18mm (9mm Makarov), 9x20mm (9mm Browning Long), 9x17mm (9mm Kurz), etc.\n\nImperial measurements play an even dumber game, because they are often just lies. .38 Special is actually .357 inches in diameter, the same width as .357 Magnum. .45 ACP is actually .451\" and .45 Colt is .452\". It gets real silly.\n\nThen you have OLD stuff, which was often measured in caliber and charge. So you get .45-70 Government (.45 caliber, 70 grains of powder) and 30-30 (.30 caliber, 30 grains). \n\nDon't even get me started on naming conventions for artillery because they are twice as insane."
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ca8tzl | why is hydrogen so common on earth and helium quite rare? | They are the two lightest elements and one atomic number apart. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/ca8tzl/eli5_why_is_hydrogen_so_common_on_earth_and/ | {
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"Hydrogen is highly reactive, it bonds to oxygen, forming water. Water is quite dense, even as a vapor, and is therefore quite durable in the atmosphere.\n\nHelium is a noble gas and nearly perfectly inert. Being unbound to any heavier elements, it quickly rises to the top of the atmosphere and is lost to space by various mechanisms. \n\nHydrogen is lost over time, but only slowly.",
"A partial answer:\nMolecular hydrogen is both reactive and escapes easily. Helium, although not reactive, escapes more easily due to its low mass. Additionally, the only source of helium is radioactive do decay. \nHTH"
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pmni3 | Why do the Russian scientists have to wait till December to study the water they took from Lake Vostok? (Lake under Antartica) | askscience | http://www.reddit.com/r/askscience/comments/pmni3/why_do_the_russian_scientists_have_to_wait_till/ | {
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"Vostok Station is one of the most [inhospitable places for humans to work](_URL_0_). December is the Antarctic summer, so the weather will be better, temperatures warmer, and up to 24 hours of daylight."
]
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1cpgy5 | I hear a lot about rape from the Red Army in Berlin during WWII. Did the German army (and SS) rape women too? If so, why isn't it talked about as much? | Particularly in their occupation of the Soviet Union, but in the rest of occupied Europe as well. I was just kind of shocked when I searched 'rape WWII Soviet women' on google and all that came up were articles about Soviet soldiers rapes. | AskHistorians | http://www.reddit.com/r/AskHistorians/comments/1cpgy5/i_hear_a_lot_about_rape_from_the_red_army_in/ | {
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"Yes, there was definitely rape committed by the Wehrmacht/SS. This is from Timothy Snyder's *Bloodlands*: \n > [The Wehrmacht] would also rape Jewish women, casually, as though this were not an offense for which they could be punished. When they were caught, they were reminded of German laws against racial mixing. \n\nRape of 'sub humans' was fairly common on the Eastern Front. I can't answer the second part of your question unfortunately. I'm in no place to speculate on that. ",
"There was far less documentation about rape under the Nazis, because Nazi race-defilement laws specifically forbid German men to have sex with Jewish women or even to kiss them. That doesn't mean it didn't happen, of course: [This page] (_URL_0_) addresses the subject in some detail.\n",
"Rape as a weapon and/or collateral atrocity of war was all too common in WWII, including by [American servicemen](_URL_0_) stationed in occupied Japan after the end of the war.\n\nAs my old Social History of War professor emphasized over and over, wherever there's war, there's rape.",
"A book that might interest you is: Soldaten: On Fighting, Killing, and Dying. It's composed of transcripts of recordings made in British prisons, mostly Wehrmacht troops talking to each other. I've been meaning to get it for a while now but I haven't gotten around to it.",
"This topic is very well covered in two Russian books: [this one](_URL_3_), called \"For What the Soviet People Were Fighting\" and [this one](_URL_2_), called \"Unknown Faces of War\". The Nazis invaded the Soviet Union in WWII with the overall mindset of creating Lebensraum and the getting rid of most of the local population (keeping some for slave labour), since Russians, Belorussians, Ukranians and Jews alike were all considered Untermenschen. When the Soviet Army was pushing the Nazis back and liberating captured towns and villages it was very often the case that they were discovered entirely empty. Houses were burnt, wells were filled with bodies and trenches filled with bodies were all over the place. \n\nRape of the local populace by the advancing Nazis was as commonplace as the fighting itself and in addition to the \"unorganised\" rape carried out normally, organised brothels were set up to service the officers and soldiers. [Here](_URL_0_) and [here](_URL_1_) are fragments from the respective two books which summarise the extent of what was going on. The sources for the books are Nuremberg trial materials and eyewitness accounts from both sides. \n\nEDIT: The following is a particularly telling excerpt: \"We went to the village near the town of Gatchina Rozhdestvenno - told who served on the Seversky airport Private Peter Shuber. - We had a mission: to bring the girls the officers. We have successfully carried out the operation, all cordoned off the house. We collected a truckload of girls. All night the girls kept the officers, but in the morning they gave us - the soldiers. In large cities, organized stationary brothels. It was standard practice Wehrmacht. \"There were soldiers' brothels,\" puffs \"were called - remember shturmbannfyurera SS Avenir Bennigsen. - Almost all fronts. Girls from all over Europe, of all nationalities, from all camps collected. By the way, an indispensable accessory of a German soldier and an officer were two condoms, which are regularly issued in the army. \" But while in Europe the Wehrmacht brothels staffed with more or less voluntarily, on Soviet soil invaders such delicacy is not going to show. Girls and women for the German soldiers for the most part collected by force - a scene that will forever remember the people trapped under the occupation. In Smolensk, for example, women dragged by the arms and hair, dragged on the pavement - in the officer's brothel, organized in one of the hotels. In case of refusal to stay in a brothel followed the shooting. After the Red Army drove the Germans out of Kerch, views of Red terrible sight presented itself: \"In the prison yard was found mutilated shapeless pile of naked girls' bodies, wild and tortured by the Nazis cynically.\"\n\nThe way the advancing Nazi army treated the captured territories was known to the people fighting in the Soviet Army, and after the turning point occurred and the captured territories were liberated, the extent of the brutailty only served to increase the anger felt by the Soviets, resulting in the mass rape that occurred in East Germany when the war came there. The Soviet materials regarding the matter are still classified, but the German director, Helke Sander, states that a million women were raped by the Soviets in [this film](_URL_4_). However, reading the accounts of what the Germans did, it's really no wonder that the Soviets responded in kind, and helps explain why Victory Day (VE Day) is marked on a much larger scale in Russia today than in the Western Allied countries.",
"Possibly because the Nazis killed so many soviets and burned their villages that it takes a lot of attention away from the rape. Soviet causalities were obscenely high for both civilians and military. ",
"The German army raped, and that has been well documented. Maybe interesting to note because it's seldom talked about, is that (for example) a lot of women were raped in Normandy by the allied forces. It's not really talked about much because the allied forces were the liberators of France, and as the liberators and it was ... uncouth to talk about the bad/horrible things the allied forces did to the local populace, or seems to have been considered so by the French authorities/populace. \n\nThis continued on to road into Germany as well - where the allied transgressions are far less publicized as well.\n\n[BBC article](_URL_0_) based amongst others on Hitchcock's Bitter Road to Freedom.",
"The answer to the second part of the question is quite obvious.\n\nCold war , the war that still exists partially today. One of the most common tactics of psychological conditioning of your own troops, was imprinting the fact : you represent order , morality , your men are best and showing that the enemy is worse trained ,equiped poorly and will inflict major attrocities on the people. In order to increase the effect you should remove the enemies reason to do so and display it as their nature.\n\nThis is the reason why we have these myths :\n\nRed army had 1 rifle per two men . (this was an isolated incident during defense of Moscow).\n\nRussians had no other tactics than frontal assaults.\n\nMillions raped on territory of Germany. (In the begging there were many incidets , but there was an order according to which any attrocities against the local population were punshable by death.) ",
"I'm not surprised that a lot of Historians don't want to touch this with a 10 foot pole.. .particularly the ones on here that are knowledgeable about Soviet Russia, Nazi Germany or World War II.\n\nThere are misconceptions about the Soviet Army in World War II, particularly when it comes to their level of technical and Organisational sophistication. \n\nThey weren't some sort of Asiatic horde riding out from the Steppes, they were an Army with a high degree of discipline and professionalism. Which makes the mass rapes that took place all the more horrifying as they couldn't have taken place without the support of the chain of command.\n\nAs for the German military, a rape would have been punished because It violated the NAZI race laws, military discipline was unconcerned about whether it was rape, but having sex with someone that was classed as less than Aryan was something that was punished serverely.\n\nDuring the NAZI occupation of western Europe, rape by the Germans of local civilian women was actually far less common than by the Allied liberators... largely because German military discipline was far harsher."
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3ioidq | Do different types of wood have different specific heats? | [deleted] | askscience | https://www.reddit.com/r/askscience/comments/3ioidq/do_different_types_of_wood_have_different/ | {
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"Wood in general is a very complicated material. The specific heat of any particular piece of wood is going to be dominated by the amount of water in that wood. So it can vary significantly not only from species to species but also within species according to what treatment, if any, the wood has undergone."
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7a7jmi | why is the greek language used in science so much? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/7a7jmi/eli5_why_is_the_greek_language_used_in_science_so/ | {
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"The Greeks in antiquity did a *lot* of science, and we kept a lot of their words for things. I've said more than once in my anatomy class that “if it's not Latin, it's Greek.” To stay on topic, Greek has a lot more words in biology and physics (including those words), and Latin is more for chemical symbols and engineering.",
"Most of what we consider 'Science' was developed in the European university system post-Renaissance. Since such universities were almost always affiliated with the Church, they created a common course of study that included Latin and Greek.\n\nAs a result, while scientists in different nations spoke different native languages, they *all* had familiarity with Latin (and, to a lesser extent, Greek). The Greek *letters* in particularly came to be used for many mathematical formulas because they were distinct from the standard alphabet, but still recognizable.",
"Greek (and Latin, which occupies a very similar position) isn't directly used in science, but Greek and Latin words are very frequently mashed together to form technical (from Greek techn-: art, skill, craft) terms. Prior to English becoming the main language of science, Greek and Latin were used because those languages were spoken and read by nearly all highly educated Europeans regardless of their national origin. For example, Newton and Linnaeus wrote in Latin. These languages also had a reputation thanks to their connection to Classical writers whose thoughts formed the starting point for education at the time. \n\nAs people stopped writing in Latin and Greek they carried over the use of terms and even expanded it. A couple contributing factors may be at play. Less nobly, it acts as a sort of gatekeeping. You have to be educated to know the meanings. Every industry has a tendency toward jargon. But there's another more practical and probably more important reason, which is that it allows greater precision. Words in English or another language already have a meaning in that language. Roots may have multiple meanings or senses to a native speaker that may shift with time. But scientific roots in Greek or Latin have defined meanings that don't shift or change. And they can also be repurposed from their original meanings and used for specific scientific meanings. For example, haploid just comes from the Greek word for single. But scientifically Haploid doesn't mean \"single\" it means \"having a single set of chromosomes\". If we tried to call cells \"single cells\" in English it would be confusing because \"single cells\" also means \"there's just one cell\". But we can use haploid for a specific meaning of the word \"single\" that strips out the ambiguity and keeps us from having to explain what we mean exactly (as long as we know what haploid means anyway). \n\nEdit: another great example of how this works is with words surrounding \"knowledge\". The very word \"science\" comes from a Latin word scientia, which simply means \"knowledge.\" But of course we use it to mean a specific _type_ of knowledge. The _Greek_ root for knowledge is _gnos_, from which we derive things like \"Diagnosis\" and \"Cognition\"...other specific terms related to knowledge. So having another language of roots to draw on can really help you come up with specific terms for more specific versions of things your language already has a word for. ",
"This is true in English and other European countries. Less so elsewhere, except to the extent that they've adopted Western scientific terminology.\n\nSo, most early Christian texts were either in Latin or certain Greek dialects.\n\nThrough most of the middle ages, the people who carried on scholarly traditions of reading and penmanship, were christian clergy, or people taught by them. So you learned the \"old languages\" by means of translating and copying old religious documents. That meant that if you were a wealthy, educated person, you knew some Greek or Latin.\n\nMoreover If you wanted to publish something in and have it understood by scholars in other countries who might not speak your language, or if you wanted people in the future to understand it......Latin or Greek. And chances are, if you wanted to quote something someone said in the past....you guessed it.\n\nMuslim scholars in the middle ages also had a role in this as well. The middle Eastern world was trading with 3 continents and collecting ideas from all of them at the time when most of Europe was constantly warring over farmland. I feel that Muslim scholarship traditionally takes accuracy in of copying religious works especially seriously. They had an advantage of dry climate where paper/parchment was a lot less likely to deteriorate.\n\nSo, middle Eastern scholars were able to preserve the writing of classical Greek philosophers. They then combined that with maths traded from India and China.\n\n Then there was a major flourishing of science in Renaissance Europe. Lots of people publishing what turned out to be pertinent and timely stuff... using Greek or Latin terms to describe things.\n\n\n\n\n",
"Latin is a so called dead language and doesn't change, so does the meaning of what you express in latin.\n\nLet's use an actual example for greek. Todays leading language in IT is english. People from all over the world can talk about IT topics in english and understand each other."
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1ukppx | Just finished watching "12 Years a Slave": Was life for slaves in the southern U.S. during the 1800's really as bad as these movies depict? What was the average life like for an average slave on an average plantation? | Believe me, not trying to undermine the abhorrence of slavery but these plantations in these slavery movies (Django, 12 Years...etc.) are always depicted so horribly, where the slave masters are literally the second coming of Hitler/Satan. I wonder if this done for effect because these are movies. I find it a bit hard to believe the average slave owner was so cruel, I can see being raised to think slaves are your property, just as you might oxen or horses, but people don't beat their horses to within one inch of their life. Because most people are just not that evil/sadistic and why do that to your property? Better to treat your property well and take care of it so it is a well performing asset. But maybe it really was so bad. Anyone have any idea? | AskHistorians | http://www.reddit.com/r/AskHistorians/comments/1ukppx/just_finished_watching_12_years_a_slave_was_life/ | {
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"I wrote a report on slave narratives. I read Frederick Douglas', Harriet Jacob's and W.E.B. DuBois (although DuBois was not a slave himself). Not every slave owner was cruel to their slaves. Although there was a stigma of a man that wasn't stern with his slaves, as the community would think that he was not doing his job as a slave owner. However, Douglas had an awful story about how he was nearly beaten to death. And Jacob's story was about how she lived in an attic for 7 years in order to avoid her master in the hopes of one day finding an escape. \nRegardless, the average slave was property, therefore given the bare essentials and often lacking that. The system was all about making money. If a slave owner thought that he'd make more productive slaves by beating them and occasionally making serious examples, then it was reasonable to do so. \nBut regardless of how they are currently depicted or whatever stories we hear from that time period, we need to be respectful of what happened and realize that it was despicable because of their status, not only their conditions. \n",
" > but people don't beat their horses to within one inch of their life. \n\nOf course they do. \n\nIn the 1930s the WPA interviewed more than 2000 slaves, who describe their treatment in detail. These are available [online](_URL_1_). [Here](_URL_0_) is a selection with brief descriptions of their contents. The first link takes you to a master link of narratives. They're quite brutal. It is not pleasant reading in any sense. Of course, Solomon Northrup's own account can also be found online, [here](_URL_1_) for example. ",
"There was a reason why masters beat slaves much more severely than they beat animals--slaves were a lot smarter. Tie an animal to a post and the animal won't and can't run away. Not so with people. If you read the book upon which 12 Years a Slave was based, you'll learn that 24/7 policing was necessary to prevent slaves from running away. You'll also note that in 12 Years a Slave, the cruelty and torture to which Northup was subjected, was not limited to just one person--it was a large number of different people in different circumstances and different states who committed it. As the WPA interviews, and other slave narratives, demonstrate, such cruelty was indeed widespread. Some slaves were lucky enough to avoid some of it. But most could not. White men could basically rape their enslaved women any time they felt like it, with no punishment or even acknowledgement that anything was wrong. In the delicate language of the 19th century, this is described in all the literature. Every slave was subject to being parted from their loved ones at any time, forever. In short, yes, things were as bad for the average slave as were depicted in the film. Not for every slave, but for a very large percentage of them. And actually, if you read the book, you'll see that things were quite a bit WORSE than were depicted in the movie. But if they had depicted it accurately, it would have become redundant and the audience would have been desensitized to the violence and degradation. What we today say is evil, was at that time considered to be normal, necessary, and GOOD. Spare the rod, spoil the child. Bible passages were quoted aplenty to show why it was important to make slaves obey and work. ",
"I didn't want to make another thread about the movie, but I wanted to ask a side question: How often were black people kidnapped and forced into slavery. It always seemed like a very plausible thing to do as record-keeping was spotty.",
"There was no average life for an average slave on an average plantation -- that's one of the reasons I really enjoyed the film *12 Years a Slave*. It shows the multiple ways that slaves existed, and the numerous strategies that slave owners adopted. One strategy was essentially a paternalist approach, epitomized in the film by Benedict Cumberbatch's character. The idea is that the slave owner won't face as much resistance from slaves if he treats them with some measure of decency, and develops a bond of some kind between slave and master. In case you're interested, this way of mediating between master and slave was famously charted by Eugene Genovese in his book *Roll, Jordan, Roll*. \n\nThe other major strategy was to inspire terror. I think that you err in assuming that these slave owners' infliction of violence on their slaves was irrational. Your comparison between them and \"Hitler/Satan\" and your example of people not beating their horses suggests this, at least to me. Rather, slave owners' violence was often quite calculated and strategic. As someone else noted in this thread, slaves were much smarter than horses. They saw that they could be beaten or killed for any act of defiance. In the antebellum South, many slave owners maintained a constant atmosphere of violence and fear, in order to keep slaves under control. Slave owners were not simply cruel for no reason. Admittedly, in the film, Epps seemed to be motivated by simple malice. Fassbender's portrayal didn't allow for much nuance. However, slave owners would have known precisely why they were attacking or beating their slaves. \n\nA final point I'll make tonight is that if we look beyond the antebellum South, prior to the abolition of the slave trade, it was not uncommon for slave owners to beat or work their \"property\" to death, knowing that they could cheaply replace them. Admittedly, this changed to an extent after the slave trade was abolished, but I would argue that the logic was not really that much different in the mid-nineteenth century United States. Slaves were replaceable, and a slave that resisted his/her master's tyranny in any way might seem to be more trouble than he or she was worth. This logic certainly holds for other kinds of property - horses, in your example.",
"I'd respond to your question with a definitive yes. I'd suggest reading up on how Cecil Rhodes exploited black South Africans in the 1800's as a way to extract minerals that were plentiful in the area, or how black people were treated in King Leopold's Congo Free State. To imperialists like these, blacks were considered to be less than human beings,were seen as instruments for economic advancement, and were treated accordingly. ",
"I find your question fascinating in that it proves that the post-war propaganda of former confederate leaders was really successful. They managed to make it sound, against all evidence, like the war was not about slavery, and that slavery was not that bad. Their declarations during or before the war attest to their dishonesty. \n\nAs for your comparison with Hitler, as far as I know he never got his hands dirty killing jews. In fact if I'm not mistaken he saved at least one, his childhood doctor and his family. At the same time, the actual perpetrators were, in their own words, \"just following orders.\" Even if the end result is similarly horrible as what you describe, nazism was thus actually much easier for the human psyche. \n\nThus it took extremely bad people, or a system powerful enough to turn normal ones into very bad ones. That's probably why racism is still so rampant in the Southern US, it had to be extreme so as to have cognitive dissonance resolve towards treating slaves like chattel.",
"Note: strictly speaking this is not an answer to this question, it is more of a meta-answer, but it provides some points which I think are important so I'm posting it regardless.\n\nFirst off, realize that it is fundamentally impossible to truly understand the nature of slavery (anywhere) through any narrative, no matter how intimate. The fact is that without spending years and years of your life as a slave, without having the sure certain knowledge that you will live all the rest of your years and die as the property of another man burned into your consciousness you can only possibly understand the rudimentary outlines of slavery.\n\nSecond, the truth does not solve this problem. The truth is, was, that the day to day life of many slaves wasn't all that bad. In fact, compared to the average experience of the average \"free\" citizen of North America through the mid 19th century it really wasn't so bad at all, and some slaves lived lives that might seem preferable compared to many non-slaves in America, even up through, say, 1850. If you were an alien from a remote stellar system who had no knowledge of the history of slavery and through some high-tech device you were able to watch, say, an entire week's worth of footage of some random subset of American slaves circa 1850 you might not think it was such a bad deal.\n\nBut such conclusions would be erroneous, and hugely so. The problem here is that humans are great at coping, it's one of our most powerful features, and statistics can lead you to incorrect conclusions because outlier events can be so important that they define the nature of a thing. As a hypothetical, imagine a father who rapes his pre-teen daughter every year on her birthday. Statistically that incest/rape is an outlier, but that event is so important that the fact that it happens at all, let alone repeatedly, makes a huge qualitative and categorical difference.\n\nAnd that's the situation with oppression in general and slavery in particular. If the master only whips one of many slaves on a plantation once over a period of a decade the fact that such a thing ever happened and that it's possible for such a thing to happen utterly characterizes the master/slave relationship. You can look into someone's eyes, you can talk with them, you can spend hours and hours with them, you can think you know them but there is a good chance that you may never learn that for them every waking moment they are living in fear. There are thousands of abused spouses in this county who are living in fear and hiding their fear from even their closest friends. Imagine what it must have been like to live as a slave in 19th century America. To know the degree to which it is codified in the informal and formal rules of society and in the laws of the land that you are less. That any white man can say anything he wants to you or order you around. That your master controls your fate not you. That your master could force you to marry whoever he chose. That your master could sell your children or your wife and you could do nothing about it. That your master could rape your wife or your daughter and you could do nothing to stop it. Less. Powerless. Worthless. Hopeless.\n\nCould you imagine how that would affect your thinking, your personality, your capacity for happiness every single waking moment of your life? And imagine how it must feel to build up little mental rationalizations in your mind, to think that your master isn't so bad, that he doesn't seem likely to ever rape you or your friends or loved ones, or sell you or them off to some other plantation. And then one day something happens that's just slightly out of character for your master, maybe he gets angry and is verbally abusive when he's never been before, who knows. Or maybe he just takes ill for a little while and you're faced thinking about what will happen if you're forced to work for another master. Suddenly your little house of rationalizations is in doubt, suddenly there is nothing that you can depend on in your life. Suddenly the possibility of being whipped repeatedly, casually executed for sport, raped or see your loved ones raped, all of that becomes a lingering possibility at the back of your mind.\n\nThat's the true horror of slavery. And it's that sort of thing that is impossible to get across without dressing up slavery in \"stage makeup\" and focusing on abuses more than ordinary daily life, because those events are by and large more relevant.\n\nAbuses were not universally the norm, they were often the exception. But the fact that they did still happen and the fact that they could happen at any time is what characterized slavery in that setting and time period. As I said, there is absolutely no way to get across the entirety of the experience of slavery through the medium of film, television, or literature, so then it becomes necessary to provide a sketch, an impression of the nature of slavery. And any such sketch which does not include abuses as a fundamental aspect of the nature of slavery in America is one that is irredeemably flawed.",
"It depends (as everything else) on *when* you are talking about. Before Slavery began to be restricted in terms of import/export, it was cheaper in French Caribbean and British West Indies sugar producing colonies to import slaves, and simply work them to death and purchase new ones, afterwards, it was not. \n\nIn that time before restriction, on sugar plantations, your idea of a slave as a performing asset held little weight and the death tolls were staggering, and are often overlooked. \n\nBut, post 1807 for the Brits, and 1808 for the US, the actual trade if not the condition of slavery ended. This made it harder to obtain slaves. The British on one track, having not had slavery in Britain itself, were on the way to freeing slaves in the imperial colonies by 1834. The US on the other hand, demurred from making a nationally binding decision and continued chattel slavery in their slave states until the American Civil War decided the question. \n\nThis makes the idea of a slave as a performing asset somewhat more valid, as simply buying up a load of new people became far more expensive, new slaves had to be bred, or bought instead of simply harvested. \n\nBut the literature and narratives often show us that far from being the kind of class that would treat a slave like one should a productive asset, and ensure full output, they instead opted for what is called the BPM in Poli/sci and economics, and that is do just enough to succeed and no more than necessary. So slaves were fed, and clothed, but not exceptionally well. They were disciplined, sometimes harshly, sometimes to death. And let us not be naïve, part and parcel of the condition of being a slave was the mental conditioning that kept them from rebelling or running away, which to the present mind, is cruel beyond comprehension. And the possibility of rape, the division of family, and of punishment unto death, hangs heavy on the present mind. These all existed, like Damocles’ sword above their heads, whether they were inflicted or not. \n\nAlthough, it also has to be said that not every slave tried to escape and some didn't see any hope in an attempt, the condition and conditioning thereof was designed to convince them of same, round the clock, their entire life. \n\nAnd furthermore, underneath that conditioning, that lay upon the human spirit like a blanket, the slave was still a thinking human being who without that conditioning, had a natural desire for freedom and a natural desire to use all of their powers to obtain that freedom, if they had not been broken. This made a strong motivation for the owning class to keep them alive and working, but not too much else, less they gain enough faculty or strength to overcome their condition by force. So treating them too well, was expressly against good management practice of the time period. \n\n\n",
"I wrote an essay in my undergrad on the sexual lives of slaves in antebellum south. [The primary source I used were interviews with surviving slaves, most of whom were children during the war.](_URL_0_) The conclusions I drew were that masters controlled virtually every aspect of a slave's sexual life, except that which the slave could carve out for him/herself in private. \n\nMasters controlled who slaves had sex with, and would \"breed\" them. They would separate them from their spouses and chidlren, and *might* consider selling families together, but pretty much only if they were convinced that such a sale would increase their productivity. \n\nMasters would have sex with their female slaves, who had virtually no way of resisting. They would use rape as punishment, as well as just because they could."
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5resu2 | why does sunset time sometimes decrease or increase by 2 minutes instead of 1? | it can get clogged and then decrease by 2 minutes
how is this so? if the earth spins once a day | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5resu2/eli5_why_does_sunset_time_sometimes_decrease_or/ | {
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"Daylight time changes vary by latitude; in July the North pole experiences 24 hours of daylight while in December it experiences 0, so there must be a change of at least 24 hours daylight time in 180 days, which turns out to average about 8 minutes a day change. At the equator no change is perceived at all (0 minutes per day).\n\nMore than that, the *rate* of change varies through the year. At the winter and summer solstices the changes are relatively slow. At the autumn and spring equinoxes the rates of change are at their highest. This is because during winter and summer the earths pole is pointing directly away or toward the sun (depending on hemisphere and season), while at spring and autumn the earths axis is perpendicular to the sun.\n\nAs a result the daily change in daylight hours varies by how North or South you are, as well as the time of year. You can explore the range of impact here: _URL_0_"
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3ph28l | why do humans have fetishes and animals appear to do not? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/3ph28l/eli5_why_do_humans_have_fetishes_and_animals/ | {
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"Let me disect your question.\n\nWhat is a fetish? Whoever you ask, be it a psychologist, a biologist or a sociologist, you probably will in detail receive very different answers.\nHowever, they will most likely all have one thing in common:\n\nSexual behaviour outside the norm.\n\nThe differences will most likely be regarding the answer of \"what is the norm / normal\"\n\nTo answer your question we will go with what the biologist may have to say about that: \nAny sexual behaviour which does not directly produce offspring.\n\nRecreational sex is simply a waste of energy.\n\nWith this - granted - very narrow definition of what a fetish is, you will be able to observe them with animals as well. \n\nBonobos, for example, the so-called \"hippie apes,\" are known for same-sex interactions, and for interactions between mature individuals and sub-adults or juveniles.\n\nOral sex also occurs with some frequency throughout the animal kingdom. It's been observed in primates, spotted hyenas, goats and sheep. Female cheetahs and lions lick and rub the males' genitals as a part of their courtship ritual.\n\nWe humans did just take it to the extrem, just like with everything else.",
"Depends on what you call a fetish.\n\nMale goats have been shown to like pee play and seeing female goats simulate sex. "
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7o45zk | Can you transmit the flu through semen? What about sweat? | Got into an interesting discussion with the wife about whether she could get my flu from a little WHOOPEE. Then I went to play hoops with friends and was wondering if my sweat could transmit it as well? | askscience | https://www.reddit.com/r/askscience/comments/7o45zk/can_you_transmit_the_flu_through_semen_what_about/ | {
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"It is primarily an infection involving the upper respiratory tract. The virus is primarily shed through coughing/sneezing. The likelihood of semen or sweat containing the virus is low and unless those fluids are inhaled it wouldn't cause an infection. "
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2qrl9b | Why are pipe organs used to play songs or jingles at hockey games? | AskHistorians | http://www.reddit.com/r/AskHistorians/comments/2qrl9b/why_are_pipe_organs_used_to_play_songs_or_jingles/ | {
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"For the same reason that they're used (or used to be used) at baseball games: volume. Even a small hockey stadium is a huge place, filled with screaming fans, and the pipe organ has the oomph to be heard in that environment.\n\nNowadays, most use \"electronic pipe organs.\" The one in Chicago's United Center, for example, uses recorded pipe organ sound, and cost something near $150,000.\n\nIt's not as fun as the one that was demolished with \"The Madhouse on Madison,\" but it still sounds good."
]
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efpfyw | What was the Roman Empire's opinion of the crusades, and how did they feel about the outcomes? | AskHistorians | https://www.reddit.com/r/AskHistorians/comments/efpfyw/what_was_the_roman_empires_opinion_of_the/ | {
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"I'm not well versed on their reaction to all of the Crusades, but their opinion of the First Crusade was initially very positive. Emperor Alexius had extracted oaths of loyalty from the prominent Crusader leaders, and promises to restore reconquered territory in Anatolia to the Romans, and this is what happened initially. Alexius gave the Crusader armies extensive supplies for their journey, as well as knowledgeable guides. He sent his navy along the coasts to help them whenever possible, and eventually sent armies in their wake to protect the conquests of the Crusaders (which, naturally, he wanted to see restored to his empire). Cooperation between the Romans and the Crusaders was effective and relation were relatively positive - both parties had the same objectives; to defeat the Seljuks and restore land to the Christians. However, things took a sharp turn when the Crusaders refused to hand over Antioch to the Romans following its capture in 1098. Alexius was understandably angry, since it was in direct violation of their previous agreements. \n\nThings took a further negative turn when the Crusaders revealed their intention of invading the Fatamid Caliphate and retaking the Holy Land. Alexius was on good terms with the Fatamids, since both of them viewed the Seljuks as a more serious threat than each other, and they agreed that it was in both of their best interests to focus their attention on defending against the Seljuks rather than fighting each other. Alexius warned the Crusaders not to start a war with the Fatamids, but they ignored him and marched down the Levant coast. The Emperor was furious and promptly cut off all aid he was giving them, including supplies and naval assistance. For the rest of the First Crusade (which at that point continued for only a few more months) there was no cooperation between the Romans and Crusaders. Alexius saw the invasion of the Holy Land as pointless from a strategic perspective and in nobody's best interests, and quickly distanced himself from the Crusaders and tried to maintain positive relations with the Fatamids, telling them he had nothing to do with it.\n\nThe only Crusader state that the Romans had somewhat positive (or at least not overtly negative) relations with was the Principality of Antioch, since its prince, Bohemund, swore fealty to Alexius as his overlord. This took some of the sting off the Crusaders' refusal to hand over the city, although Roman control of the principality was minimal and tensions were always high, since the princes simultaneously were influenced by the Kingdom of Jerusalem as well.\n\nSource: *God's War: A New History of the Crusades* by Christopher Tyreman",
"u/Wonderfully_Mediocre’s not at all mediocre post already goes over the First Crusade, so I’ll just link to some previous answers of mine about that: [When the Crusaders left Anatolia, was the Levant still covered by their oath to return territory to the Byzantine Empire?](_URL_2_) and [Why did Bohemund declare himself the Prince of Antioch, not the King?](_URL_1_)\n\nAfter the First Crusade, the Byzantines were happy that Jerusalem and the other holy sites were in Christian hands again, but they wanted to make sure that the rights of Greek Christians were respected (which they were very often not, under crusader rule). Otherwise they didn’t really think anything of it from a political point of view, since Jerusalem was strategically unimportant to them. They did have a fairly good relationship with the crusader kingdom in Jerusalem; the royal families intermarried, and they tried to conduct military expeditions together (particularly against Egypt), but the Byzantines didn’t really want to rule anything except Antioch.\n\nFor the Second Crusade, both Louis VII of France and Conrad III of Germany travelled through Constantinople, as the First Crusade had done. In that case, the Byzantines were fairly worried: \n\n > “The appearance of a large crusading army was a cause for grave concern in Constantinople. Unlike in the background to the First Crusade, when Alexius I had requested a western force to come to his aid, there was no such invitation in 1146-7.” (Phillips, *The Second Crusade*, pg. 170)\n\nSicily had been attacking Byzantine territories around the same time, so the Byzantines worried that the crusaders were working with the Sicilians. They were also worried that the crusade would besiege Constantinople, but the crusaders had no intention of attacking the empire and they were eventually ferried across the Bosporus and made their way to Jerusalem. \n\nConrad wasn’t technically the Holy Roman Emperor, so there was no problem with two emperors both claiming to be the Roman Emperor, as there was on the Third Crusade. I answered [a previous question](_URL_0_) about that as well: Holy Roman Emperor Frederick Barbarossa and Byzantine Emperor Isaac II both claimed to be the legimitate Roman emperor so it was extremely difficult for them to agree to anything. The other problem for the Third Crusaders was that the crusaders believed the Byzantines were [secretly allying with Saladin](_URL_3_) to destroy them. The Byzantines were probably just exploring all their diplomatic options though, not conspiring against the crusade specifically. \n\nIn any case, the problems on the Third Crusade were also overcome and the German crusaders made their way to the Holy Land (although Emperor Frederick died along the way). The other contingents from England and France avoided the overland route and took the sea route, but the English managed to somewhat accidentally conquer the Byzantine province of Cyprus. The Byzantines were not particularly happy about that, but Cyprus was ruled by a rebellious lord, so it was really already outside of the authority of Constantinople.\n\nThe Fourth Crusade is of course an entirely different matter…the Byzantines, in hindsight, obviously felt that it was a huge disaster for them. Very briefly, the emperor at the time, Alexios III, had deposed the previous emperor, his brother, the aforementioned Isaac II. Isaac’s son Alexios IV came to an agreement with the leaders of the crusade to divert it from its original target (Egypt) to Constantinople to restore Isaac to the throne. So, there were at least some Byzantines who were in favour of that…but not many, since the people actually living in Constantinople were opposed. Alexios IV and the crusaders did manage to restore Isaac to the throne, with Alexios IV as co-emperor, but then Isaac died. Alexios IV was then overthrown and murdered by yet another Alexios, who became Alexios V. The crusaders were still there though so they attacked and conquered the entire city. The disastrous part of this in Byzantine eyes was not the rapid overthrow and murder of various emperors (which happened often enough), but the crusader sack of the city. The Byzantines were always paranoid that a crusader army showing up at their door would sack the city, and finally with the Fourth Crusade, it actually happened. \n\nThe other crusades then largely bypassed Constantinople, because it was already under Christian control - interestingly, the problems faced by the First, Second, and Third Crusades, arriving at a somewhat hostile Constantinople, would have no longer been problems for the Fifth, Sixth, and Seventh Crusades, but the later crusades avoided it anyway and took the faster sea route.\n\nSources:\n\nCharles M. Brand, Byzantium Confronts the West (Harvard University Press, 1968)\n\nJonathan Harris, *Byzantium and the Crusades* (Hambledon and London, 2003)\n\nJonathan Phillips, *The Fourth Crusade and the Sack of Constantinople* (Pimlico, 2005)\n\nJonathan Phillips, *The Second Crusade: Extending the Frontiers of Christendom* (Yale University Press, 2007)"
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"https://www.reddit.com/r/AskHistorians/comments/c32r3y/in_1185_holy_roman_emperor_frederick_barbarossa/eroprbo/",
"https://www.reddit.com/r/AskHistorians/comments/dzjznq/why_did_bohemund_declare_himself_the_prince_of/f8a1qi0/",
"https://www.reddit.com/r/AskHistorians/comments/diaqov/when_the_crusaders_left_anatolia_was_the_levant/f7lzlyr/",
"https://www.reddit.com/r/AskHistorians/comments/ddnhst/during_the_third_crusade_why_did_byzantine/f3axyo9/"
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6szlkx | how are you assigned to classes in college? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/6szlkx/eli5_how_are_you_assigned_to_classes_in_college/ | {
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"You'll talk to an advisor who will give you a schedule based on the program you are enrolling in. "
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9535js | why does throwing an extremely light object, for example a golf ball, strain the arm as opposed to a baseball that is relative in mass? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/9535js/eli5_why_does_throwing_an_extremely_light_object/ | {
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"The same reason you should never dry fire a bow (shooting a bow without an arrow in place). If there is no arrow to transfer the energy of the pulled bowstring, all of that energy will go into the bow itself and can damage or shatter the bow.\n\nYour arm functions the same way as a bow: transfering energy into the ball (arrow). A lighter or smaller ball doesn't require as much energy to launch. If you perform your normal throw on the lighter ball, the excess energy not transferred to the ball will travel back through your arm and can strain it especially if you don't do a full follow-through to help release the energy."
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10p2r8 | Why is there so much Carbon-14 in these fossils? | I searched this sub for similar posts. There were some close matches but nothing regarding fossils with such a high concentration of C14.
Here is the article: _URL_0_
This topic was discussed over in /r/DebateAChristian, and I was asked to pose this question to the experts.
Thanks in advance.
| askscience | http://www.reddit.com/r/askscience/comments/10p2r8/why_is_there_so_much_carbon14_in_these_fossils/ | {
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"That's quite a lot to read over for so little potential gain. Could you be more specific?",
"There's a lot of crap on that page.\n\nFirst, carbon dating doesn't work for things like dinosaur fossils. They're too old.\n\nThe number 22,380 has no reference next to it so I'm not sure which reference at the bottom they're referring to.\n\nThe premise of the article is that in 2005 a fossil was dated to 20-30k years. None of their references seems to point to this event, nor does Google come up with anything that's not a blog or some anti-evolution web site. Hugh Miller comes up a few times, he's apparently a creationist.\n\nThere's nothing on that page that can be responded to without vomiting."
]
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4tob1b | As the needle approaches the centre of a record, its speed increases, right? Are the grooves cut differently towards the middle of a record to account for this? | Is it magic or is it science?
Edit: [6], in case you were wondering | askscience | https://www.reddit.com/r/askscience/comments/4tob1b/as_the_needle_approaches_the_centre_of_a_record/ | {
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"The grooves aren't intentionally cut differently, but the wavelength representation is longer near the edge compared to the center because the speed of the track increases from the center to the edge. Since the grooves are cut directly into the recording material, no external adjustment is necessary, since it's always going to be a 1 to 1 correspondence when played back at the same speed it was cut.",
"Early floppy-drive computers included some models which varied the speed of the disc drive, as the head moved across the radial distance. This is constant linear velocity, as opposed to constant angular velocity.\n\nLP cutting heads are often linear track. The cutting needle is on a screwshaft. LP reading heads are typically designed to pivot. Audiophiles used to argue if this mattered, if the parallelogram of forces on the needle didn't accurately track what was cut. Some LP players therefore had linear drive reader heads, but not all golden ears agree they sound better.",
" > As the needle approaches the centre of a record, its speed increases, right? \n\nIncorrect.\n\nThe record always spins at, say, 33-1/3 rpm. The diameter of a standard LP is 30 cm, so when the needle is at the outer edge, it passes along about 90 cm of groove for each revolution, or about 52 cm per second. If the diameter of the label is about 10 cm, then when the needle gets in to the center, it passes along only about 30 cm per revolution, or 17 cm per second."
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7pw6gm | How was the East India Company able to maintain rule over the massive subcontinent for over 100 years? Was it stable? Was it more than a loose administration? How much indigenous resistance was there? Did this change under direct British rule? | AskHistorians | https://www.reddit.com/r/AskHistorians/comments/7pw6gm/how_was_the_east_india_company_able_to_maintain/ | {
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"While there were a numerous way in which the English East India company were able to maintain control over their massive Indian territory , I will cover some important ways in which they exerted control :\n\n#**Part 1**\n\n#**Control over the rulers**\n\nOne of the important pillars of power of company support were a loyal class of local rulers . These rulers were helpful because \n\n1) They helped maintain an illusion of indigenous rule when in reality they were nothing more than company stooges .\n\n2) They helped in suppression of local rebellions and other minor disputes that were not big enough or important enough to warrant the use of the company army\n\n3) By getting support and loyalty of these indigenous rulers , They hoped to obtain a sense of legitimacy as they often touted themselves as the protector of mughal empire and in later years as successors of the mughal state\n\nBut how did the company develop this class of royal rulers?\n\nThe Company exerted control over the rules and various kingdoms via mainly the \n\n* Subsidiary Alliance system \n* Protection alliance and protective custody \n* Picking sides in succession disputes to install a puppet \n* Doctrine of Lapse and Adoption \n* Using wars between rival Indian kingdoms to their advantage\n\nLet us understand each of the above in a brief manner\n\n***Subsidiary alliance system***\n\nUnder the subsidiary alliance system , The ruler agreed to enter an alliance with the company . The terms of these alliance were as follows:\n\n > An Indian ruler entering into a subsidiary alliance with the British would accept British forces within his territory and to pay for their maintenance.\n\n > * The ruler would accept a British official (resident) in his state.\n\n > * The ruler who entered into a subsidiary alliance would not join any alliance with any other power or declare war against any \n power without the permission of the British.\n > * The ruler would dismiss any Europeans other than the British and avoid employing new ones.\n > * The ruler would let the British rule on any conflict any other state.\n > * The ruler would acknowledge the East India Company as the paramount power in India.\n > * The ruler would have his state be protected by the Company from external dangers and internal disorders.\n > * If the rulers failed to make the payments that were required by the alliance, part of their territory would be taken away as a penalty.\n > * Indian rulers have to maintain British troops in his state. \n\nAs you can see after reading the above terms , Any kingdom which entered / or was forced to enter into a subsidiary alliance was reduced to nothing but a kingdom with a rubber stamp ruler who were official puppets of the company on almost all matters of importance \n\n*Examples of kingdoms which entered the subsidiary alliance system : Awadh , Many maratha princely kingdoms ,Tanjore , Indore etc*\n\n***Protection alliance or protective custody***\n\nMany Indian rulers or royal families who were afraid of being attacked by their rivals or by members of their own house often entered British protective custody . These forms of agreements generally involved the Company defeating/killing/driving off the enemies of the person seeking protection . In return for these , The ruler would become predisposed to the company and do what the company advised them in case they needed the company protection in the future again \n\n***Picking sides in succession disputes to install a puppet***\n\nThe company often took advantage of succession disputes to further their own advantage . They would select one of the people involved in the disputes and offer their support , resources and help to get the throne . In return , the ruler would have to promise to be favor and have good relations with the Company when he becomes the ruler \n\nSuch actions were also often done when they felt that a ruler soon to come to power in a throne would be bad for the prospects of the company \n\nIn most of the cases , Getting the official support of company on your side generally meant that the game was over for the opposing side more or less\n\nThus , by helping these rulers ascend the throne , they got a loyal group of rulers who they could rely on in times of difficulty \n\n***Doctrine of lapse and adoption***\n\n > Under an ancient Hindu custom, to avoid a disputed succession to the throne, a ruler with no born-to heir could adopt a male of any age from another branch of the ruling family and appoint him heir apparent. This parallels similar customs in ancient Rome and during the Chinese Qing Dynasty.\n\n > When the British Empire came to India in 1757, among the land-grabbing stratagems devised was the Doctrine of Lapse, which abrogated the ancient custom. Under this doctrine the British arrogated to themselves the right to veto the succession of an adopted heir, and instead, to annex the territory concerned, although the adopted successor and his heirs were usually allowed to keep their titles and a substantial annual allowance. \n\nThus , this one more method to install a puppet regime in many kingdoms . Many big Indian princely thus fell to this policy \n\n~~**# Part 2 to follow soon**~~\n\n# ***Part 2*** \n\n# ***Military power of the company***\n\nThe army of the East India Company were one of the most feared and powerful in the subcontinent uptil its dissolution in 1857 \n\n* Company army had massive superiority over indigenous kingdoms in terms of artillery , firepower and firearms ,military discipline and military tactitcs\n\n* To help the company further , they had a exceptional and experienced class of military commanders and officers who had experience fighting in many terrains and countries in different parts of the world . In many wars , the company won not to due to superior quality of equipment , but rather due to the experienced officers and commanders leading the charge during the war .\n\n* The trademark red coat and bucket coat that the company is now famous for stuck fear in many Indian kingdoms. In order to increase troop morale , many Indian kingdoms introduced a similar looking uniform for their own army \n\n* The payment system of the company was **extremely punctual**. The company placed a great emphasis on ensuring that due salary payments were done to all troops . This ensured that the Company army became a lucrative job for many Indians . The best and smartest of various kingdoms often tried their hands to get a job in the company army \n\n* Any disturbance anywhere in the country that had the potential to weaken company hold over power invited a visit from the Company army . Many regiments in the company evoked special fear such as the Bengal regiment which were the backbone of company power in the country \n\n# Part 3 to follow soon\n\nMeanwhile you can read my answer regarding opinion of various sections of the Indian society towards East India company to understand the flames of discontentment that were rising in the Indian society\n\n[Answer](_URL_0_)\n\n\n# ***How much indigenous resistance was there?***\n\nLet me quote you a section which will directly answer this part of question\n\n > Among the myths which became current in the wake of the rebellion of\n1857-8 was the idea that it was a unique event, something that had to\nbe explained in terms of the peculiar folly of the revenue policy of the\n\n > With this in mind, several broad types of dissidence can be isolated\nfrom the great range of revolts between 1800 and i860. Most notable\nwere the periodic revolts of zamindars and other superior landholders\nfighting off demands for higher revenue or invasions of their status as\n'little kings' in the countryside. Then there were conflicts between\nlandlords and groups of tenants or under-tenants objecting to the\ntransformation of customary dues into landlord rights or to some violation of the obligations between agrarian lord and dependant.\nNext there was a range of conflicts arising from tension between wandering\nor tribal people and settled peasant farmers which usually\ncentred on the control of forests, grazing grounds or other communally\nexploited resources. Finally, there were frequent revolts in cities\nand towns. These had many causes: some were riots over market control\nand taxation. Some involved bloodshed between religious or caste\ngroups or the protests of embattled artisan communities. All these\ntypes of conflict were widespread but they surfaced in exaggerated\nform in the course of the Mutiny and Rebellion of 1857.\n\nSource for the above quoted text :Indian society and makings of british empire",
"[1/2]\n\nI would like to add a few points here, because u/HarshKarve's posts seems to me very strongly (if not to say solely) informed by a British perspective, leading to a rather positive overall assessment of the East India Company. Although they quote a short paragraph on resistance at the end, it basically seems in the post as if the British were in control due to their superior strategies and military. This is misleading, because in fact indigenous resistance to colonial rule was continuos from the beginning in the Raj in the late 18th c. roughly until the rebellion of 1857, which led to the British Crown taking over. Also and crucially it reinforces colonial stereotypes that don't ascribe agency to non-Europeans (here from South Asia), effectively writing them out of history. So it's important to keep in mind that British rule was far from secure even as late as 1857, where in the first months it was not clear at all that the British could regain control. \n\nHaving said that, I'll especially focus on two points below: 1) native resistance, and 2) (more briefly) changes under British rule. \n\nThe EIC increasingly formed a parallel state in India, with private armies and great administrative control. It had managed over decades to take over princely states and form an economic basis. To do so it had increasingly built on indigenous sources and networks of information gathering since the 1760s (cf Bayly, Empire and Information). However, all this came at a cost (C.A. Bayly, Indian Society making British Empire, 106):\n\n > The [EIC] rose to power because it had provided a secure financial base for its powerful mercenary army. The land revenues of Bengal, combined with the capital - Indian as much as European - generated in the coastal trading economy, allowed the Company's Indian operations to sustain the massive debts incurred in its fight to finish with the Indian kingdoms. However, political dominion did not solve the Company's financial problems. The ominous presence and constant pressure of this part-oriental, part-European state continued to tempt petty rulers within and outside its domains into revolt. Though aspects of the social and political conflict which had drawn the Company into expansion were suppressed under its ruler, so too was much of the economic dynamism which had given rise to that conflict. India's huge agricultural economy was not performing well enough to underwrite the costs of European dominion. The [EIC]'s rule widely came to be seen as a dismal failure long before the Great Rebellion of 1857 blew up its foundations. \n\nWe should note that this perception of the Company's failure was not just from Indian perspectives, but that there were important discussions in British parliament in the 19th c. over restricting the company's influence. One major criticism there was the perceived corruption of the EIC's leading administrators. Another point to add here is that the perceived \"low performance\" of the native economy is connected also to British tactics of importing British textiles to India which would over the long-term weaken this important branch of South Asian economies (among other influences). Adding to this was that the \"*needs of its financial and military machine had tended to snuff out that buoyant entrepreneurship of revenue farmers, merchants and soldiers which had kept the indigenous system functioning*\" (ibid). As mentioned such developments taken together led to resistance in various forms and for various reasons.\n\n.\n\n**Indigenous resistance to colonial rule**\n\nI'll begin by quoting [an earlier reply of mine](_URL_1_) on the time preceding the rebellion of 1857:\n\n > The rebellion took place 100 years after the beginning of the rule of the Easty India Company (EIC) in South Asia, and has to be understood as a continuation of a long tradition of local resistance to colonial rule (that continued up to independence). In this light, the rebellion was particular in its scope, but not in its goals and demands. There were many different kinds of and motivations for resistance: Among others religious insurrections, banditry, acts of revenge – but also peaceful opposition. Most of those insurrections were connected in some way to the very common economic exploitation and political marginalisation through the EIC, and thus to popular discontent. \n\n > It's also interesting to note that such discontent ran through all social classes. As a common ideology we can identify the central role of the community principle to the rural populace (including the caste system), and that of traditional land rights. Most (if not all) of these motivations for and forms of resistance played major roles during 1857. On the other hand, the lack of a coordinated, unified organisation meant that the British could count on parts of the local population, and was a major influence in the rebellion's failure.\n\nLet's look a bit closer at those earlier revolts: At almost any moment during colonial times a rebellion or revolt took place somewhere in SOuth Asia. There are reports of hundreds of revolts already in the 17th century, and according to Kathleen Gough there were at least 77 agrarian revotls from the 18th c., drawing tens to hundreds of thousands of peasants. While they were officially called 'localized', they actually took place on larger territories than those of the well-known European agrarian revolts when considerian South Asia's huge size. Certain areas had more frequent revolts taking place, esp. Bengal, but also tribal areas of modern-day Andhra Pradesh (Hyderabad) und Kerala (in the South West).\n\nAs a larger ideology behind such resistance we can see the central role of the *community* principle for the rural populace, especially the spiritual foundation of the caste system and traditional land rights: \"*Community as 'the characterisitc unifying feature of peasant consciousness*\" (Chatterjee). This served to seperate friends from traditional foes during revolts - between, but also within religious groups. Another feature of the community was the major role of politico-social justice. Justice could take the form of rights to complaint, peaceful forms of protest such as migration. An important result of this was that even people of the lower classes could reclaim their rights before local authorities -- which was not possible anymore in this way under the _URL_0_ many revolts can be connected to a pre-colonial sense of justice not compatible with British conceptions, which because of this were often not succesful. Then again, revolts often led to adaptions of the colonial system, e.g. throiugh agreements with local leaders and groups from which they could profit. \n\nI'll now look in a bit more detail at forms of resistant other than those agrarian revolts, and then turn to consequences of the revotl of 1857 (1857 itself falls sort of outside of the scope of this):\n\n- Revolts of land owners/ *zamindars*: These went against larger tributes and the lowering of their status. E.g. when the British tried to move one of their candidates onto the throne of a realm (as mentioned in the above post), contrary to the political alliances of a given region. Especially frequent was resistance in regions that had never been under Mughal control, but were now supposed to be controlled by the EIC (or its rulers). Examples include Awadh and Bundelkhand. Privileges were accorded by the British to local leaders in order to thwart further rebellions.\n\n- *Resistance of village leaders:* Here often the sole possibility was moving away or deserting, but also revolts took place (Dekkan 1850s/'60s, Konkan 1857-'59). In addition there were conflicts within rural societies, between landowners and tenants, which only increased with the stronger influence of cash cropping. Tenants often reisted the transformaton of their land rights; and conlficts between non-sedentary tribes and sedentary farmers were also quite frequent.\n\n\n\n- *Religious unrest*: Oftentimes agrarian conflicts took on religious character through the influence of reformist Islam. This was the case with the Faraizi movement in Eastern Bengal (1820s to '50s), which revolted in favor of weavers and their taxation, and attacked Hindu money-lenders as well as European indio-estates. Moreoever there was an increase in revolutionary messianism taking place, esp. in Muslim (but also in Hindu) communities reeling from theri increasing social deracination. These were collective movements looking towards a sacred realm on earth, and for an imminent huge change through supernatural means. Apocalyptical preachers (like Tipu Sahib in East Bengal) prophetised the end of British rule and mobilized mountain tribes in this way.\n\n\n\n- *Urban revolts*: Were connected to economic and religous difficulties. Once more the decrease of urban weavers and artisans led to revolts of these groups. In their own organisations muslim faith would often strengthen communal ties, and strikes against local officials and traders happened often. The most frequent resistance in cities came from the elites -- they were against colonial taxations and taxation of houses. The replacement of traditional guardians of the law through colonial officials further led to agitation.\n\n.\n"
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2p89e4 | In a chemical reaction, if the product has a lower energy than the reactant, why doesn't all reactant convert to product? | If there is a reaction: A-- > B and B is more stable or has a lower energy than A, then the equilibrium position will typically be more B than A. But, why doesn't all A convert to B if B has lower energy? | askscience | http://www.reddit.com/r/askscience/comments/2p89e4/in_a_chemical_reaction_if_the_product_has_a_lower/ | {
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"Reactions have an [activation energy](_URL_0_) associated that acts as a barrier from all reactants rapidly and spontaneously turning into products. That is, there requires some extra energy put into the reaction before it can proceed. Commonly this is heat energy - hence reactions occurring faster at higher temperatures."
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60avpy | Why is there such a thing as "critical mass" for a radioactive material? Why couldn't the chain reaction sustain itself with less mass than the critical amount? How is this mass calculated? | askscience | https://www.reddit.com/r/askscience/comments/60avpy/why_is_there_such_a_thing_as_critical_mass_for_a/ | {
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"The reason for the chain reaction in the first place, is a chance for a neutron emitted by an atom to hit another atom. This event in turn emits even more neutrons. If those manage to hit an atom, the chain will continue.\n\nCritical mass ensures that emitted neutrons do not just miss everything and fly away, but they keep hitting more atoms (because there are enough atoms around). This gives you a sustainable chain reaction.\n\nThere is no simple formula for calculating the exact value of the critical mass. It depends on cross section of the material, energy of emitted neutrons, presence of neutron reflecting shield around the material etc. Figuring out the critical mass value for a particular material is basically what physicists get paid for. ",
"Fission results in the release of 2 to 3 free neutrons. To sustain a critical chain reaction, on average, one of these neutrons should be captured by a fissile nucleus and cause it to fission.\n\nSo what you need to understand is the parameters that affect how likely it is for a free neutron to be captured in this way.\n\nOne important parameter is the shape of the material. If a neutron escapes the material it is lost from the system and doesn't contribute to the chain reaction. This is called leakage. A sphere is the most efficient shape as it has the smallest surface area from which leakage will occur for a given volume. We also want to maximise the density of the material as this will also minimise the surface area for a given mass.\n\nThe larger the mass of the sphere the less likely it is a neutron will escape i.e. a neutron will on average have to pass by more fissile nuclei before it can escape the edge of the sphere. For each pure fissile material of full density in a vacuum there is an ideal spherical mass where a just critical chain reaction will occur. Any less material and there will be too much leakage and the system will be subcritical.\n\nThis critical mass can be reduced by adding a reflector around the fissile material. Beryllium is an excellent reflector, as it has a high neutron scatter cross section and a low neutron capture cross section (I'll come back to these terms in a bit). By adding a thick shell of beryllium around our spherical critical mass we minimise leakage and thus reduce our critical mass.\n\nThe next thing to understand is how neutron capture or scatter cross sections vary with neutron energy. Cross sections are measured in barns, a unit of area. The bigger the cross section, the more likely it is that a neutron will be absorbed or scattered when its comes into proximity with a nucleus. After a fission the free neutrons are \"fast\" and have an energy in the MeV range. By slowing down neutrons to a \"thermal\" energy in the eV range the cross sections increase significantly and neutrons can more easily captured. So if we reduce the average neutron energy then we need on average fewer interactions between a neutron and fissile nuclei before a capture occurs. In which case the volume needed for a chain reaction reduces further. Slowing down neutrons is achieved by including a \"moderator\". This is a material with a low atomic mass which reduces the energy of a neutron by elastically scattering it. This is analogous to a pool ball being slowed down by multiple collisions with other balls by transferring some of its energy to them. The best moderator is one with a similar mass to a neutron as momentum transfer is most efficient at equal mass. A secondary factor is that the moderator should not capture too many neutrons. Hydrogen-1 is by far the most effective moderator. The next best, deuterium, is much less efficient at absorbing momentum energy. Again we want to minimise the size of our sphere so we want a material with a high hydrogen density. Water has a good hydrogen density, but polythene is even better.\n\nSide note: Moderation also has a secondary benefit in that thermal fission produces slightly more neutrons per fission than fast fission on average. This further improves our balance of neutrons available for the chain reaction.\n\nThe next point to make is that a nucleus can absorb a neutron without contributing to fission. This is called parasitic absorption. This can happen with the fissile nuclei itself, which is unavoidable, with the moderator and the reflector and also with any impurities that may be present. To minimise this we want to exclude any impurities and to use just enough moderator mixed in a ideal way with the fissile material (a homogeneous mix for high enriched uranium and plutonium or a lattice for very low enriched uranium).\n\nTaking all of that into account we can now design our system with a minimum critical mass. Most minimum critical masses reported will be for pure u-233, u-235, pu-239 and pu-241 mixed homogeneously at maximum density with an ideal concentration of polythene, surrounded by beryllium.\n\nThe differences between the masses for each fissile isotope are due to there different capture-fission and capture-parasitic absorption cross sections and the differences in the average number of free neutrons produced per fission.\n\nTechnically there are some ways we could produce an even smaller minimum critical mass. In theory beryllium hydride is an even better moderator than polythene and could result in a critical mass of as little as 87 grams for pu-239. Additionally some of the higher transuranics are also fissile and have very very small minimum critical masses (a few grams, maybe less). Both of these cases are a bit academic and not really relevant in industrial settings (e.g. Where want want to know the minimum critical mass for safety control purposes).\n\nEdit: How is it calculated? These days we use computer software to very accurately model a system. The most accurate tools are Monte Carlo models that individually model the fate of many postulated neutrons until the statistical error is negligible. These models are validated against a library of test data. The better validated the data, the more accurate the model. There are analytical approaches that can be used, with formulas to estimate the effects of geometry, moderation, etc (try googling geometric and material buckling as an example). These are rarely used outside of a classroom as the software models are more effective and widely available."
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5uk349 | how do hackers hack a web cam? | And is it possible for them to record without the indicator light turning on?
EDIT: specifically a laptop's built-in webcam - if that makes a difference... | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5uk349/eli5how_do_hackers_hack_a_web_cam/ | {
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"Generally speaking, they don't. The public Webcam feeds you can find online are usually there because of shit security settings on peoples' networks and computers.\n\nIf someone had the skills to rewrite or modify the webcam driver file, it would be pretty easy to change the settings to not turn on the light.",
" > How do hackers hack a web cam?\n\nBugs. A lot of software is insecure. Not all. A standalone webcamera is an \"Internet of Things\" device. Oh god, there are so many poorly secured IoT devices. \n\n > And is it possible for them to record without the indicator light turning on?\n\nDepends. If the light is hardwired to the power of the camera, no. But other devices, like [logitech cameras](_URL_1_) or [macbooks](_URL_0_) don't even need the firmware flashed. So, that's a solid yes. \n\n > specifically a laptop's built-in webcam - if that makes a difference...\n\nAs a device that's part of a real laptop, with a real OS, then it's probably more secure. But on the flip side, OS's do a lot more stuff which are more vectors for an attack. \n"
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35ej48 | Do Historians studying Colonial America *need* to be fluent in Native American Languages? | I'm an undergraduate History student interested in studying Colonial America (and more specifically, relations between Europeans and Natives) as a graduate student. All programs I've looked into require reading proficiency in only one language (I'm learning French).
I've had it mentioned to me that as a Historian of Early America, I'll also need fluency in Native American languages to translate primary sources. All primary sources I've been able to locate are in English, even those from Native Americans to Europeans.
Is this true? I'm not opposed to learning a NA language, but there doesn't seem to be much opportunity to do so in my surrounding area, either. | AskHistorians | http://www.reddit.com/r/AskHistorians/comments/35ej48/do_historians_studying_colonial_america_need_to/ | {
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"Probably not. Many of the indigenous languages at that point were only spoken languages and were not written, which is why you aren't finding many, if any, sources in an indigenous language. You should be fine if you focus on one of the European languages (French or Spanish if you are studying an area colonized by the Spanish). In the unlikely event that you need an indigenous language for your area of research, your future advisor will tell you and help you find a way to learn it.",
"To move through graduate school you would not *need* to be fluent in Native American languages. It sounds like it could not hurt, given what you would like to study, but the fact is, most historians of colonial America do not know any Native American languages, much less have fluency. The major reason for this is not necessary euro-centrism, though that doesn't help, but rather that most historians gather their data and evidence from written sources, which, almost by default, are filtered through Europeans and European languages before being recorded (or as they are recorded). This means that there are few truly Native American sources available in that form, so many historians, even of those who look at European-Native American interactions, are not what you would call fluent in any Native American language. Of course, if that will be your main focus, it cannot hurt to learn as much as you can, and also to investigate the Native American cultures you'll study such as they exist today. Generally, a historian of such interactions tries to get as much perspective as possible, by approaching the subject from as many angles as possible. I highly recommend \"Facing East From Indian Country\" by Daniel Richter for you, as his introduction discusses exactly this issue of recovering Native American perspectives and opinions when the overwhelming majority of information about them and their interactions has been filtered through Europeans and Colonists first. The rest of the book attempts to engage in just such recoveries in a number of instances.",
"A lot of this depends on your particular subject. For example, if you're doing work that connects to extant groups and potentially their oral histories (a methodology that requires mastery in itself!) you may. However, often the acquisition of those languages happens in the field, precisely because they are not normally taught in an instructional setting. In learning certain southern African languages, that was my only choice--even going to teachers who work in the language wouldn't help, because they were already dealing with native speakers, not second-language speakers. So you may well not be able to acquire a relevant one to you until the need is apparent.\n\nI will say that having such a language, and more importantly a demonstrated ability to work in that language, is a helpful differentiator on the market. But for the era you're discussing, it's not an absolute requirement for the general field. When we did our colonial US search, none of the finalists had a Native American language. Constrast that, if you're curious, to our most recent US West/18th-19th search, where two of the four finalists had research ability in a Native American language. As /u/Mictlantecuhtli points out below, the need is very subject- and geography-dependent.",
"Even if you don't need it for translating primary sources, I think that it would be a sign of respect and thoughtfulness to learn the language that is or was most prevalent in the main location of your research. It might give you insight into the structure, interests, and investments of the culture you're studying\\*. Studying the protocols that go along with language in conversational settings with peers and with elders may help you to develop relationships, and thereby gain appropriate, respectful access to oral histories directly from the source in an ethical, non-exploitative manner. \n\nCould you do some research without this knowledge? Absolutely. Could you do more, more interesting, and maybe more groundbreaking research with it? I think so. But you'd probably have to seek out a graduate institution with the programs, training opportunities, and community links to help you on your way. \n\n\\*For example, as far as I understand it, the Cree language uses different grammatical structures for animate vs. inanimate nouns, but the dividing line does not line up with a Western scientific/biological understanding of what constitutes an animate object. "
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144z2t | Will Solar Energy Ever Surpass the Efficiency of Fossil Fuels and Will it be a Viable Source of Energy for the Future? | I read [here](_URL_0_) that photovoltaic cells are ~13-16% efficient (not sure how accurate that is). It got me thinking because I watched [this](_URL_1_) and I was put under the impression that fossil fuels are extremely efficient. Is the efficiency of a photovoltaic cell and/or battery holding us back from a solar energy dominant civilization? How can photovoltaic cells be made more efficient? | askscience | http://www.reddit.com/r/askscience/comments/144z2t/will_solar_energy_ever_surpass_the_efficiency_of/ | {
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"You're comparing apples to oranges. You can't/shouldn't compare efficiency across different methods of extracting energy. What you should care about is dollar pr watt hour. ",
"The major problem with solar is it only works about 8-12 hours a day. Then not at all during the night. So, if you wanted 100 % solar 100 % of the time, then you have to design a system for the extremes of weather patterns. I live in Alabama, and over the summer we went 5 straight days with thick overcast. That is some huge batteries. \n\nThe main reason fossil fuels are winning, and will continue to do so, is because they provide on demand power and are more reliable. Germany's wind turbines are currently facing this problem. They produce so much during the night, which is when energy is in the least demand. That it causes issues on the grid. ",
"I'm certaily not qualified to give a definite answer for your overlying question, but I can give a couple details/points of clarifiation:\n\nCurrent photovoltaic (PV) cells (made of mostly silicon) have an efficiency of ~22 %. The upper limit for singly layered silicon PV cells is ~33 %. This is considering three phenomena: that silicon (and pretty much everything else, called blackbody radiation) radiates at all times (~7 % drop), that not all excitations will last long enough to be useful (~10 % drop) and that some sunlight will be too low energy to induce excitations, while high energy sunlight will not be used to its fullest (~52 % drop) ([ref for these](_URL_0_), [alternately the wiki article](_URL_2_)). Silicon-based PVs are generally considered a pretty mature technology.\n\nA type of solar that shows some promise is called a dye-sensitized solar cell. Unfortunately, that's where my knowledge ends, so the best I can do it [reference you to the wiki article](_URL_1_).\n\nEdit: sorry about some overlap hithisishal's comment"
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3bn75c | why do marathoners and triathletes tend to have small body frames? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/3bn75c/eli5why_do_marathoners_and_triathletes_tend_to/ | {
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"Most body frames (skeletons) are very similar, and most \"shape\" comes from fat or muscle on those bones.\n\nThe heavier you are, the more work you have to do. It's easier to move 150 pounds 100 feet than 200 pounds 100 feet.\n\nRunning results in injury to heavier people more often. Joints stand up better to 150 pounds coming down on them than 200 pounds. This is a \"[squares and cubes](_URL_0_)\" problem. Stuff gets heavier basically in a cubic function, stuff gets stronger basically in a square function. n^3 grows much faster than n^2.\n\nMarathoning and training burns a lot of calories. Compared to eating less, running isn't usually as effective for weightloss, but when you start talking 20 miles, you're talking about burning in the area of 2500 calories, which is more calories than the average person should consume per day. ",
"Running long distances or doing aerobic exercise is very taxing in terms of calories burned. In short distance sprints, very tall and muscular people have the advantage due to length of stride and the power that extra muscle bulk provides, but with long distances, those muscles and that extra height becomes just extra baggage that you have to carry for 20 or so miles. Adding 50 pounds and half a foot of height can bring up the amount of calories required to complete the run by about 1000. This goes up even further if you want to be competitive."
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3oux22 | How is the primality of extremely large numbers tested/proven? | There are know primes with few million digits. How do we actually know this numbers are indeed prime? | askscience | https://www.reddit.com/r/askscience/comments/3oux22/how_is_the_primality_of_extremely_large_numbers/ | {
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"This probably isn't exactly how they do it computationally, but intuitively you could do this:\n\nEvery number can be uniquely factored into primes, i.e. 10 = 2*5, 28 = 2^2*7, etc. \n\nIf a number is prime it only has one factor, itself. If a number is composite, it is made of of 2 or more prime factors. \n\nIt's not too difficult to see that a composite number, call it n, has some factor less than sqrt(n). So all you have to do is divide n by all the primes less than sqrt(n). \n\nIf you don't get a whole number for any of those divisions n is prime.",
"For very large prime numbers we use probabilistic tests like Fermat's test or Miller-Rabin and others.\n\nThe largest known primes are at the moment Mersenne Primes and they are found primarily by using the Lucas–Lehmer primality test.\n(And other algorithms in a certain context.)\n\nEDIT: A Miller-Rabin test e.g. will not give us a 100% accurate answer, but we can \"tweak\" the algorithm to give us a very good accuracy.\n\nEDIT2: If we really want to be 100% sure we can do an expensive trial division, but that takes some time.",
"There are fast primality tests: _URL_0_. These tests aren't easy to understand, and we only proved that they are \"fast\" (polynomial time in the number of digits) recently. Historically, we used imperfect algorithms that basically just tell you that a number is \"not prime\" or \"almost certainly prime.\"\n\nIf your goal is just to hunt for very large primes, then one way is to use the Lehmer-Lucas test. Given a prime p, it's computationally easy to find out if a number of the form 2^p - 1 is prime.",
"Wrote an honors thesis on this.\n\nFirst, start with Fermat's Little Theorem: (x^(p-1) - 1)/x is a whole number if (but not only if) p is prime.\n\nThe contrapositive statement: \"p is not prime if (x^(p-1)-1)/x is not an integer\" identifies most composite numbers in one test. But there are numbers - called Carmichael numbers - that fool this test. 1729 = 7 * 13 * 19 is one such number - (4^1728 - 1) is a multiple of 1729, and this is true if you replace 4 with any whole number that isn't a multiple of 7, 13 or 19.\n\nSecondly, you hunt for Carmichael numbers by the following method: You hunt for a square root of 1, modulo p, that is not equal to -1 or +1. (That means you look for x such that x^2-1 is a multiple of p, but neither x-1 nor x+1 is a multiple of p). For 1729, an example of such a square root would be 246. 246^2 - 1 = 35 * 1729.\n\nThe existence of such a square root enables you to find a proper factor of p.\n\nThe way to do this is to consider each of x^1728, x^(1728/2), x^(1728/4), x^(1728/8)... until you are raising x to an odd power for each of dozens of values of x. There is a theorem that if p is prime, no more than 1 in 4 possible values of x will fail to have a proper square root of x in this series.\n\n\nThis provides a practical test that allows you to probabalistically test if a number is prime. PROVING it is prime beyond a sliver of doubt then requires elliptic curve primality proving - where you construct a mathematical group (the abstract algebra concept of group) of points with certain properties on a curve of the form y^2 = x^3 + ax + b and define an operation on those points. This allows you to reduce the problem of 'is p prime' to be equivalent to 'is p1 prime' for a number p1 with p1 < p^0.5. Repeated iteration of this allows you to then get to a number small enough to check it against a table of known primes (in practice, usually once you get under 100 billion you just do this)."
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kb7n7 | Is MDMA really harmless? | I keep hearing that it is. Then there's [this picture](_URL_0_) from The Lancet.
At the same time I can recall reading that the rush of seratonin confuses and overloads the reuptak mechanism that usually deconstructs seratonin in the synapse before transporting the parts back into the cell, leading the reuptake enzymes to cut and bring back everything they see, including dopamin. Dopamin which produces bleach when cut in this way, thus killing seratonin cells in bulk.
Not only that, but receptors can get overexcited and retreat into the cell, leaving you feeling dulled if only some do it while giving you a full blown chemical depression if many do, lasting for anything from years to forever.
And apparently there's also other toxic byproducts that users claim to be able to thwart using 5-HTP and inhibitors. How much truth in this?
So which one is it, relatively safe (low risk of dangers mentioned above or dangers mentioned above are a fiction of my imagination) or not?
| askscience | http://www.reddit.com/r/askscience/comments/kb7n7/is_mdma_really_harmless/ | {
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"One of the problems you'll note when reviewing literature on MDMA is the recent influx of research on MDMA assisted psychotherapy. This research tends to be biased towards showing the safety of the substance, and it's making it harder and harder for unbiased research to make clear conclusions about MDMA. It might be part of the reason why you're getting mixed messages.\n\nWith that said, even within the unbiased scientific research, there isn't a clear understanding on what exactly the relationship is between MDMA and permanent neuronal dysfunction. It is well accepted that high dose MDMA use is associated with long-term dysfunction of serotonergic circuitry, and for a long time it was thought that the dysfunction was actually from neuronal death. However, more recently there have been studies that challenge this because with CNS death you should see certain glial cell markers, and those markers aren't seen in high dose MDMA associated serotonergic dysfunction. So with serotonin at least, we know that MDMA disrupts normal functioning, but we don't know the exact mechanisms. Similar findings of acute dysfunction with dopamine and norepineprhine have been reported, but it's generally felt that the monoamines are not disrupted as severely as serotonin or with as much concern for permanence. \n\nThe last thing I'll mention is that most of this research is done on primates and occasionally rats, and less is known about the specifics in humans. With all of that said, I certainly wouldn't classify it as \"safe\" or \"harmless\" especially when used in high doses, but the exact mechanisms and potential for permanent neural dysfunction are not clear at this point.",
"Layman here, but I did spend a lot of time doing drugs and researching on [erowid](_URL_0_) in my younger days. It seems like you know what you are talking about and already know this information, but this information **needs** to be in this thread for someone who clicks across it an decides to use this thread as justification for taking a tab.\n\nThe problem with street MDMA is that it's rarely pure. One tab might contain 25% mdma, 25% meth and 50% caffeine, while another will contain 50% psilocybin and 50% mephedrone. This makes determining the safety of a tab very difficult without a test kit and the proper reference materials to check on the behaviors of different chemicals when mixed and their safe doses.",
"One of the problems you'll note when reviewing literature on MDMA is the recent influx of research on MDMA assisted psychotherapy. This research tends to be biased towards showing the safety of the substance, and it's making it harder and harder for unbiased research to make clear conclusions about MDMA. It might be part of the reason why you're getting mixed messages.\n\nWith that said, even within the unbiased scientific research, there isn't a clear understanding on what exactly the relationship is between MDMA and permanent neuronal dysfunction. It is well accepted that high dose MDMA use is associated with long-term dysfunction of serotonergic circuitry, and for a long time it was thought that the dysfunction was actually from neuronal death. However, more recently there have been studies that challenge this because with CNS death you should see certain glial cell markers, and those markers aren't seen in high dose MDMA associated serotonergic dysfunction. So with serotonin at least, we know that MDMA disrupts normal functioning, but we don't know the exact mechanisms. Similar findings of acute dysfunction with dopamine and norepineprhine have been reported, but it's generally felt that the monoamines are not disrupted as severely as serotonin or with as much concern for permanence. \n\nThe last thing I'll mention is that most of this research is done on primates and occasionally rats, and less is known about the specifics in humans. With all of that said, I certainly wouldn't classify it as \"safe\" or \"harmless\" especially when used in high doses, but the exact mechanisms and potential for permanent neural dysfunction are not clear at this point.",
"Layman here, but I did spend a lot of time doing drugs and researching on [erowid](_URL_0_) in my younger days. It seems like you know what you are talking about and already know this information, but this information **needs** to be in this thread for someone who clicks across it an decides to use this thread as justification for taking a tab.\n\nThe problem with street MDMA is that it's rarely pure. One tab might contain 25% mdma, 25% meth and 50% caffeine, while another will contain 50% psilocybin and 50% mephedrone. This makes determining the safety of a tab very difficult without a test kit and the proper reference materials to check on the behaviors of different chemicals when mixed and their safe doses."
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fs4px3 | what is economic contagion? | Don't want to bring any recent news, but I hear about this phrase called "Economic Contagion".
Could somebody please explain to me what this means and why does it have to do with a global economic crisis? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/fs4px3/eli5_what_is_economic_contagion/ | {
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"Without bringing current events into it:\n\nAn \"economic contagion\" or \"financial contagion\" is the idea that effects in the economy - particularly bad ones - have a way of spreading from one market to another.\n\nA \"market\" can be an industry - for instance, if the housing industry sees fewer people buying houses, then in turn the banking industry is impacted when fewer people take out loans, which in turn impacts other businesses who rely on the banks' strength.\n\nA \"market\" can also be a country - if a country's production takes a major hit, then its trade partners will be affected, any places relying on tourism or other cashflow from the country will be affected, etc.\n\nThe idea of an economic contagion is an attempt to explain real-world events. The word \"contagion\" is kind of controversial because these effects don't really have much in common with an infectious disease in any way; they are simply an effect of financial interdependence.",
"Most business and currency is based on confidence and belief. \n\nBelief that things will largely be worth tomorrow, what they are today.\n\nConfidence that the systems and structures that are useful and effective today, will remain so for the indefinite future.\n\nWith these ideas, you can plan on a micro-level how to allocate your time and money. On a macro-level, economies do the same thing.\n\nProblems arise when you lose confidence and belief. Should you plant your fields? Can you sell your produce in six months? Should you build a new expansion? Where should you put your money? Stocks? Guns? Gold?\n\nNothing has actually happened, but you are starting to consider or make choices that don’t follow the usual pattern. I see you doing that and I get spooked and change my behaviour. Now you and I are both acting unusually and spending or saving money in ways that spook our suppliers and customers... Things start spiraling, even though again, nothing has changed except you got a little panic-y."
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25psxq | Why is there such a hard cut-off in the glacial lakes in Canada and northern US? | I'm from north eastern Indiana, and there are still a sort of large number of lakes around where I'm from. I go to (went to) school at Purdue, and there are no lakes, but there is the Wabash River. If you keep going north, it is lakes all day, all the way up to the north pole, with ever increasing frequency.
So why are there so many glacial lakes up there, how deep are they, and what keeps them there, rather than becoming rivers or something?
I read [this askscience post from 2 years ago](_URL_0_), but I still have questions. I would also really enjoy being pointed to more information resources so I can just read about it for a while. | askscience | http://www.reddit.com/r/askscience/comments/25psxq/why_is_there_such_a_hard_cutoff_in_the_glacial/ | {
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"It has to do with comparing the previously glaciated terrane with areas which were not (or minimally) glaciated. The lake-rich northern terranes are underlain by glacial sediments. These typically include large proportions of poorly sorted material (such as till) as well as glacio-lacustrine clays, both of which give rise to poor drainage. The landforms created by deglaciation also create all sorts of variations in topography (kames, thermokarst, moraine, etc.) where small shallow lakes can form in these relatively impermeable deposits. \n\nYou will find that the unglaciated areas are much better drained, and probably generally flatter.\n\nYour state is sort of half and half - the northern part was glaciated while the southern part was not."
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2c16kp | How can fish swim their entire lives? | I know that not all fish need to keep moving in order to prevent suffocation, but that some fish do. For the ones who do - how are they able to swim their entire lives? I realise that fish are perfectly adapted for life in the water, and that they probably use very little energy by swimming, but surely even then their muscles must get fatigued eventually? If I was to leave my house now and walk an infinite distance, I'd get far, but at some point I'd have to stop and rest my muscles. Don't fish have this problem? | askscience | http://www.reddit.com/r/askscience/comments/2c16kp/how_can_fish_swim_their_entire_lives/ | {
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"How do you breath all your life? Your diaphragm muscles must surely tire of pulling air in all the time, if you spend all your life breathing. Or your heart, which pumps blood nonstop your whole life.\n\nSome muscles don't tire because they can't. They're too important.",
"Its not just their muscles that are specialized for swimming constantly. Fish also have a whole specialized organ called a swim bladder that allows them to adjust their buoyancy by pumping water in and out of the swim bladder. Since buoyancy is a hydrostatic force produced by the water itself, the fish expends very little metabolic energy when using the swim bladder to adjust its position. A fish can adjust its swim bladder at any depth so that its weight is supported entirely by the water. This means that a fish can float on the surface of a body of water, or float at the bottom. Wherever it is in the water, a fish is *always* floating. A fish experiences virtually no gravitational resistance thanks to the swim bladder and buoyancy. This cuts down on metabolic expenditure massively. The fish's relatively weak and small striated muscles can focus entirely on lateral movement, while the swim bladder can be used to adjust vertical position at very very small metabolic cost.",
"Those fish that need to keep moving to prevent suffocation often simply place themselves in a way that they face an underwater current. This has the same effect as moving around in still water and the fish are thus able to relax for a while."
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3j5hm7 | What role did pike phalanxes play in late 16th and 17th century warfare? | With the prevalence of firearms and artillery, it seems to me like dense formations of pikemen would be slaughtered on a battlefield in the late 1600's. My question is: How would a typical commander of the time deploy and utilize his pike infantry effectively? | AskHistorians | https://www.reddit.com/r/AskHistorians/comments/3j5hm7/what_role_did_pike_phalanxes_play_in_late_16th/ | {
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"By the time period in question, the pike blocks [(*not* phalanxes)](_URL_0_) have taken further and further secondary roles to shot/firearm troops. \n\nIn the early 16th century, the shot troops are there to support friendly pike blocks and harass enemy pike blocks when contact is made. By the 17th century the proportions have changed drastically. A figure from *\"Fighting Techniques of the Early Modern World\"* shows:\n\n* 1622: 10 deep formation, 3 pikes for every 2 muskets.\n* 1630: 8 deep formation, 1 pike vs. 1 muskets.\n* 1650: 6 deep, 1 pike vs. 2 muskets. \n\nYou can guess where the trend was heading. Swedish infantry in the 30YW deployed about 1-1 pikes-muskets, and this isn't much different from what the Imperial and Spanish troops deployed, even if the Swedish ran smaller squadrons than their adversaries. \n\nBy the 1650s period, the pike block was a smaller contingent with muskets on both sides. Or rather, perhaps it is more accurate to say that an infantry squadron was a 6-deep line of muskets with a few pikes concentrated in the center. If that squadron is threatened by horse, the pikes then move forward and muskets back behind them to get protection. \n\nYou may want to read through [previous answers](_URL_1_) on pike and shot formations in battle. "
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3tu0f3 | how someone like marvel can copyright something like thor and loki? | These are creations/myths that are centuries old. How can you just lay claim to them? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/3tu0f3/eli5how_someone_like_marvel_can_copyright/ | {
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"They can't. What they can do is copyright their portrayal of them, so if you write a story or draw cartoons about one of them which is so close as to be mistaken by the man in the street for their version, then they'll jump on you.\n\nOf course, they might well try anyway, which is enough to put many people off - which is an abuse of the copyright system, but i suspect it happens all the time.",
"They don't. They lay claim to their specific versions of Thor and Loki / the specific elements they wrote into the story. You are still completely free to write a different version of them, or write a version based solely on the myths. You just can't use the stuff Marvel added to the stories.",
"What they hold the copyright on is the specific imagery that they created and the stories they wrote. Their copyright doesn't extend to things they didn't create.\n\nAs a result, you can absolutely make a movie about Thor, as long as it's not based on Marvel's character. For example, there was a [mockbuster](_URL_0_) that did exactly this, captalizing on all the publicity for Marvel's Thor; The Asylum release [Almighty Thor](_URL_1_) that was based on Nordic mythology and their own writers.",
"They can copyright the look/design of *their* interpretation of Thor/Loki and they can copyright their screenplay/etc. but the concepts and names of the characters are not copyrightable outside of a narrow context.",
"First off, you're confusing copyright and trademark. The comics that Thor and Loki are in are copyrighted. The Marvel characters \"Thor\" and \"Loki\" are trademarked.\n\nTrademarks work a lot differently than copyright, and the two have different purposes. A copyright protects the artist from their work being sold/distributed without their permission (e.g. uploading a movie to YouTube). A trademark protects it's owner from others profiting off of that's trademark's popularity (e.g. Motorola can't put the Apple logo on their phones).\n\nMarvel's \"Thor\" and \"Loki\" and trademarked characters. Anyone else who uses Thor and Loki in a way that might make consumers think that Marvel Comics produced or endorsed those products would be trademark infringement. That doesn't stop people from using those characters (the show up in a lot of other media. The book \"American Gods\" comes to mind). But it does stop those characters (when they show up elsewhere) from looking extremely similar to their Marvel incarnations, or from talking about their last adventure with The Avengers.\n\nIn another example, T-Mobile has a trademark on the color magenta. Does that mean no one can use the color magenta? No. Does it mean that Verizon can't put up big magenta signs that say promoting a \"switch from T-Mobile and get your first month free!\" - yes.",
"Short Answer - Marvel can't copyright Thor and Loki outright. They can only copyright their particular interpretation of them.\n\nCopyright protects original artistic expression for a limited amount of time. Copyright law also recognizes that very few artistic expressions are truly 100% original. So instead of only protecting those things that are 100% original, the law allows separate protection of adaptations/arrangements/reinterpretations to the degree that they provide a new expression of an existing idea. \n\nExamples - The novel *The Hobbit* was published in 1937 and is still protected by copyright. In order to use the characters and storylines from the book, one must have the rights to the book. Since the recent films are an adaptation to a new medium (and many things from the books were changed), the filmmakers can claim a copyright on things particular to the film adaptation, such as particular depictions of characters, dialogue original to the film, or new storylines. \n\nIn the case of Thor & Loki, Marvel does not own the rights to anything from Norse Mythology, but only the characters as they have created them and the stories they have written for them to the degree they are new. For example, the fact that Thor uses a hammer, Loki is a trickster, and Odin is the chief god are pulled from Norse mythology and cannot be copyrighted. But the particular visual character designs, location designs, and new storylines are protectable. Nothing can legally stop others from creating content using characters named Loki and Thor and elements of Norse mythology, but the closer those interpretations get to the Marvel interpretations, the greater chance they have of violating Marvel's copyright."
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216k2t | appears to be water on the road ahead. | When you're driving on a flat road and it appears to be covered in water only to disappear as you move closer. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/216k2t/eli5_appears_to_be_water_on_the_road_ahead/ | {
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"It's a mirage. \n\n_URL_0_"
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ikjza | If deaf people put their fingers against the diaphragm on a speaker, could they "feel" the music? | [Diaphragm](_URL_0_) | askscience | http://www.reddit.com/r/askscience/comments/ikjza/if_deaf_people_put_their_fingers_against_the/ | {
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"Deaf people actually dance to music. Anyone can feel the music, especially if it is very bass heavy, without touching a speaker. \n\nOne of the best concerts I've been to had an amazing sound engineer and you could feel everything. "
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43769n | why do only some animals have recreational sex, while other animals only have sex purely with the intent of reproduction? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/43769n/eli5_why_do_only_some_animals_have_recreational/ | {
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"There are several factors, the main ones that come to mind are that the animals are more advanced and therefore can understand pleasure, while more \"simple\" creatures only know mating, feeding, dying. Secondly, some organisms do not experience orgasms, so sex is not a pleasurable experience even from the start. Other factors which come in to play all sort of branch off from these.",
"It has mostly to do with the mating behaviors of specific animals. If we're talking about higher vertebrates (mammals, birds), lots of animals will engage in coitus if given the opportunity, presumably because it feels good and/or they have a strong natural instinct to do so. However, not all animals have the opportunity to engage in recreational sex because they don't form stable pair-bonds like humans. Take rutting animals, like elk for example. Pretty hard to go in for a casual lay if every time you make a move, some bro-elk comes along and tries to smash his antlers into your face to c-block you.",
"The simplest explanation is that pleasure is for those who can feel it. Pleasure is a motivational tool given to animals by evolution to seek out what's good for them; therefore, sex is pleasant *because* it leads to fertilization. For others mating is instinctive behavior.\n\nSome mammals like bonobos, capuchin monkeys, lions, macaques, cheetahs and dolphins were reported to perform some form of sexual activity when fertilization wasn't possible, which indicates pleasure-driven motivation for sex. The urge to seek that pleasure is believed to be **a combination of instinct and desire for reward** (e.g. orgasm). "
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hu6z3 | Is it really possible to colonize other planets considering the laws of special/general relativity? | When I was in high school I read Brian Greene's "The Elegant Universe" and I remember it crushing my dreams of an intergalactic future. Specifically, even if we could somehow create spaceships that flew fast enough to move between solar systems or galaxies, the time paradox (or whatever) would mean that by the time I left Earth and arrived on a different planet, hundreds of years would have passed back home but only a few years (or something) on the ship.
I obviously don't actually know that much about it all, but whenever people bring up "colonization" of other planets I just think about that time difference, even just the time difference based on the speed and gravity of a planet, and how impossible it would be to ever stay interconnected/organized with off-world civilization.
So, AskScience, what's your knowledge say about this subject? | askscience | http://www.reddit.com/r/askscience/comments/hu6z3/is_it_really_possible_to_colonize_other_planets/ | {
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"It's not as crazy as you imagine. The entirety of human civilization is a small place today, it takes mere hours (or sometimes minutes) to travel to the other side of the planet, and it takes mere milliseconds for messages to travel around the world. But it wasn't always that way. For much of human history it took years for news and trade to make its way from one region to another. And some regions were effectively cut off from each other (such as the Americas and the rest of the world). In comparison, being able to send and receive huge volumes of data at the speed of light is a massive improvement, even if it takes tens, hundreds, or thousands of years for that data to be received. Interstellar colonization is technologically possible, but it'll result in a different sort of civilization than we're used to.",
"Barring some absolutely groundbreaking discovery, I doubt we will ever get outside of the solar system. The distances are pretty extreme.",
"If we create the technology to travel at close to light speed relativity kicks in and makes things possible. According to Carl Sagan's Cosmos you could travel to the center of the Milky Way in 21 years ship time. Earth on the other hand would have experienced 30,000 years. In addition, with a ship that can keep accelerating getting ever closer to the speed of light you could circumnavigate the known universe. Earth however would have gone through tens of billions of years with the sun having long ago charred it to ashes. So it's certainly a one-way trip and your issues with trying to stay connected to the home world are valid.\n\nWormholes however bring up other possibilities since this connects two points in the universe. I highly doubt we'll ever be able to create, maintain, and travel through one though. ",
"As long as you don't care about communicating with the people back on Earth, this doesn't pose a problem."
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e7ptdq | why don’t all phone services send texts over the internet (like apple’s imessage does)? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/e7ptdq/eli5_why_dont_all_phone_services_send_texts_over/ | {
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"The short answer is that they don't because they didn't originally.\n\n*Short Message Service*-messages, as they are called in the GSM standard among other more recent standards, is a technical feature offered in the communication protocol used to communicate to and from the phones.\n\nInternet traffic relies on one or several other technical substandards that are also offered in the communication protocols.\n\nFrom the phone operators point of view, a SMS is awesome. Because they have full control.\n\nThe problem, if you wish, is that since they have full control, they also have pretty pricey business models. Or had, at least.\n\niMessage, WhatsApp, Line, Facebook Messenger, Google Hangouts, Signal, Telegram and all the others are internet services that happen to be linked to your phone number. SMS is a phone network service that is offered to your phone number. It doesn't necessarily have anything to do with the internet.\n\nThe idea is pretty much that if the phone plan has a pretty decent cost for data (and often there is a monthly allowance of sorts in the data plan...) it's cheaper to use the data plan for your messages than to pay for each individual message that you send out.\n\nBut. Smartphones too must follow the phone network communication standard. They *must* be able to receive SMS. Which means that they all can. No matter if your grandma has a brand new iPhone 11 (or whatever the newest one is?) or if she runs around with a Motorola from 1996, the terminal has SMS reception capabilities. And probably sending capabilities too.\n\nIt's also a pretty dumb thing if you compare an iPhone and an Android phone; Google has their text messaging app. Apple has theirs. They don't work well together. If you want to communicate with others, you have to first agree on which app to use for your communications.\n\nWith SMS, you don't. You just have to know the phone number, and that's it. Which is why your phone falls back on SMS every time it tries to communicate with someone who is not on iMessage. Because SMS always works. If you typed in the correct number, the message will be received."
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2vmvdt | Did fighting cease at night during the Battle of Stalingrad, or did soldiers fight 24 hours a day? | AskHistorians | http://www.reddit.com/r/AskHistorians/comments/2vmvdt/did_fighting_cease_at_night_during_the_battle_of/ | {
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"Since I would imagine fighting never stopped and only slowed , I would like to ask an additional question. Did either the Russians or German troops have any tools to aid in thier night vision? I always hear about the Japanese Navy having great night optics but did generals or armies have access to night optics? ",
"Please keep in mind that answers in this subreddit need to follow our rules. An answer consisting of four sentences is not an acceptable answer. We value answers that are **in-depth** and comprehensive.\n\nTo quote our rules:\n\n > Answers in this subreddit are expected to be of a level that historians would provide: comprehensive and informative. As such, all answers will be assessed against the standards of Historiography and Historical Method. You should cite or quote sources where possible. A good answer will go further than a simple short sentence. As described here, \"good answers aren't good just because they are right – they are good because they explain. In your answers, you should seek not just to be right, but to explain.\"\n\nIf you are not completely certain about what you're writing, then refrain from writing. Also refrain from writing if all that you can contribute is a quote from a website, a link to a website or if you do not have the time to contribute more than a couple of sentences. This applies to **all** answers, not only the top level comments.",
"In reading just now excerts from \"Stalingrad: The Fateful Siege: 1942-1943 By Antony Beevor\", Its talks of how Chuikov had ordered an emphasis on night raids because the Luftwaffe could not respond and that he was convinced it struck fear into the Germans. It talks about the use of flares to constantly trick soldiers into a belief of an imminent attack. \n\nIn addition a comment from a corporal about the \"eerie change in sound\" of the U-2 bi-planes used for night time bombing as the pilot would turn off the engine on assault until the bomb hit. \n\nSo a constant psychological onslaught from the Russians, the author comments as well that the Germans were exhausting ammo as they would fire at anything during the night. \n\nedit: type in: \"Stalingrad night raid\" the piece i read should be in Google books.\n\n"
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1zlnw6 | Why does water form the shape it does when poured? | I was just pouring water from my cup into the sink after dinner and I thought it was interesting why the water formed the shape it did when falling from the cup. I can best describe it as perpendicularly 3d sin graphs with the same x-axis, if that helps. First things first - is there a name for this formation? But to answer my main question, why does water do this? Is this shape only (or more) applicable to polar substances like water? If so, is the shape caused by the polarity of the water molecules? I tried pouring a non-polar substance (olive oil) from a cup of the same type but it was hard to tell how different the fall really was from that of water.
[Sub-par stock image for reference](_URL_0_) | askscience | http://www.reddit.com/r/askscience/comments/1zlnw6/why_does_water_form_the_shape_it_does_when_poured/ | {
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"The shape is dependent on a lot of things. Some are properties of the water itself like viscosity, density, and surface tension. Some are properties of the environment like gravity, density/viscosity of the air you are pouring into. Some are properties of the way you actually pour the water like the shape of the container and its mouth, the velocity of the water as it crosses the mouth and the distance that it falls.\n\nThe shape of the stream of water is dependent on all of things and probably some I didn't mention. The system is complicated enough that you can't say the shape is because of this one thing - they all influence the shape. The best way I could describe it is to say that the stream gets its shape from the edge of the mouth of the container and the amount of fluid flowing over the edge. Once it clears the edge, it's original momentum will be conserved and it will be accelerated by gravity. That will stretch it out as it falls, but surface tension will hold it as a single stream for a certain distance. The sine like shape you see is some combination of all these things. "
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2f9qyi | If island chains like Hawai'i were formed by the continuous movement of a plate over a magma plume in the mantle, why do they take the form of separate islands rather than a continuous ridge? | askscience | http://www.reddit.com/r/askscience/comments/2f9qyi/if_island_chains_like_hawaii_were_formed_by_the/ | {
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"Easy. Because the volcanoes do not put out magma (which forms the islands) at the same, consistent rate that the plate is moving. Kilhuea is erupting steadily right now, but that's after a long lull in activity. The eruptions go in all directions as well, changing from eruption to eruption. But for most of the island's history the plate has been moving steadily.",
"To form a continuous line, you would have to assume that magma plumbing is continuous; that is that you apply magma at the base of the crust at position x and it comes out at y above, apply at x+1 and it will come out at y+1. That is not the case.\n\nMagma plumbing is highly discontinuous; magma will preferentially propagate along fractures and pre-existing weaknesses in a system. A pool of magma accumulating at the base of the crust will tend to propagate along the same route it first successfully found. That route will be used until the low-level magma suipply is cut off. At this point a new low level accumulation will form, until it too finds itself a new plumbing route.\n\nConsider too that the ocean floor is cut by numerous large faults which cut through pretty much the entire plate - these and their related structures can form preferentially weak loci for magma injection.\n\nThe vast majority of magma never even makes it out to the surface - most is simply crystallised at depth in magma chambers which dead-end several kilometres below the surface, or are injected as dykes or sills within the host strata.\n\nIt's a bit like considering the population living around a city, and thinking that you should be able to draw a straight line from their house to the centre, and that will be their route in, resulting in a perfectly radial distribution of travel. In reality, they move along main arterial roads because that is the *easiest* route, rather than climbing over fences, walking through other peoples houses, and navigating the *shortest* route.",
"The plate's movement is more or less constant (~10cm per year) while the magma activity experiences periods of flow. It seems like once a volcanic feature is formed, magma tends to want to keep flowing within that structure. Once the plate moves far enough the magma is forced to find a new path of least resistance and breaks through the seafloor creating a new volcano. These older features can remain occasionally active; Hawaii has three volcanoes still considered active.\n\nIn addition, the islands are being constantly eroded. This is why the oldest islands are the smallest. Maui, Molokai, Lanai and Kahoolawe all used to be one big island. In the future Maui will eventually be divided into two islands. Most of this erosion is due to fresh water via rainfall and wind. At higher elevations freeze/thaw contributes ~~greatly~~ to the breaking up of rock.",
"This assumes plate motion is actually constant. When we determine rates of plate motion, we are often looking at evidence of movement over time scales in thousands to millions of years. While rates may average out to a few millimeters per year, that is still just an average. Movement along fault lines or plate boundaries consists of discrete events with long periods of dormancy in between.\n\nThis coupled with the discontinuous activity of mantle plumes and changes in the direction of plate motion, as described elsewhere in the comments, give us small islands instead of a single strip of land.",
"I saw a great video explaining it. You know that stereotypical steam train where there's little puffs coming out at regular intervals? That's what it's like with Hawaii, except the steam is magma. So the plates move while the magma gives little puffs making a really long chain of islands that actually goes all the way to Kamchatka. These little islands formed on \"hot spots\". So you get a poof on the hot spot, an island forms, plate moves, hot spot gets hot again, poofs, and it keeps moving in a chain like that. Like a conveyor belt. \n\n\nEdit: found the video. Sorry there's an ad. _URL_0_",
"The word \"continuous\" is a little misleading here. It doesn't mean a perfectly even, smooth movement, releasing magma at a constant rate in a regular and unchanging plume. The reality of any large-scale natural process is that there's frequently a large amount of variation over time, caused by the surrounding environment, the driving forces behind the process etc.\n\nAs an illustration, here's something you can try: Place your hand on a surface like a table or counter top, and exert a little pressure downwards. Now move your hand forwards slowly and continuously...",
"Near Brisbane, Australia there is North and South Stradbroke Island, which used to be a solid island before a cargo ship salvage operation using explosives put a nick in the middle of it with sea erosion eventually separating the two halves within two years. \n\n_URL_0_\n\nSo, one answer to your question could be separation by erosion which would likely happen to any magma formed long island to create island chains. ",
"Because the level of activity is not constant enough for one caldera to stay open continuously. It will become less active and the existing caldera will close. Then activity will pick up, and a new one will open. "
]
} | [] | [] | [
[],
[],
[],
[],
[
"http://www.history.com/topics/us-states/hawaii/videos/how-was-hawaii-formed"
],
[],
[
"http://en.wikipedia.org/wiki/Stradbroke_Island#Island_division"
],
[]
] |
||
364ctn | why do brownie corners taste better than brownie centers? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/364ctn/eli5_why_do_brownie_corners_taste_better_than/ | {
"a_id": [
"cralseb",
"craqje7"
],
"score": [
27,
3
],
"text": [
"Brownie center lovers are going to debate you on this, but the reason is because the brownie edges simply taste different due to a process called a [maillard reaction](_URL_0_).",
"Off topic, but who would want that shriveled up crunch edge? I'd much rather have a gooey, decadent middle slice. "
]
} | [] | [] | [
[
"http://en.wikipedia.org/wiki/Maillard_reaction"
],
[]
] |
||
1pt58w | what is the difference between gdp and ppp? | Is PPP simply GDP per capita? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1pt58w/eli5_what_is_the_difference_between_gdp_and_ppp/ | {
"a_id": [
"cd5qr9a",
"cd5re5q"
],
"score": [
3,
2
],
"text": [
"GDP is the gross domestic product, the total output of the entire nation's industries and workers. Sometimes they list this as \"GDP per capita\" which means how much each person would contribute to that total if it were divided equally.\n\nPPP is purchasing power parity, it's a determination of how much one person could buy with their income, by comparing their currency to another country's. This is sometimes different than GDP per capita because of exchange rates, artificial price controls or tariffs, and various subsidies.",
"The gross domestic product is the estimated total value of all \"final goods and services\" produced within a nations geographic borders. In this case final goods are things that are sold to consumers and are not resources that are going to be used to manufacture another product. It includes goods that are produced within a nation, but the manufacturer doesn't necessarily have to be a company of that nation. It is used as an economic indicator to basically judge if a national economy is expanding or contracting but can also be used for other purposes like comparing one nations economy to another. There are a couple of different ways to calculate it, one is based off of how much money we spend, and the other is based on how much money we earn, and the two different methods will produce two different results.\n\nThe Purchasing Power Parity is used to compare the buying power of money in different nations and compare different currencies to establish exchange rates. Basically they assume that units of currency are equivalent, for example 1 dollar equals 1 euro, and then they see how much of each it would cost to buy the same or similar goods in their respective nations. If it costs less euros to buy something in Europe than it does dollars to buy it in the US, then that shows that the euro has more purchasing power than the dollar and by how much."
]
} | [] | [] | [
[],
[]
] |
|
eow4ic | In curling, how do sweepers influence the path of the rock? | askscience | https://www.reddit.com/r/askscience/comments/eow4ic/in_curling_how_do_sweepers_influence_the_path_of/ | {
"a_id": [
"feia8up"
],
"score": [
2
],
"text": [
"The ice has little bumps on it. Sweeping away the bumps to smooth the ice allows the stone to speed up on the left or right side therefore making essentially different drag on the left or right causing it to turn."
]
} | [] | [] | [
[]
] |
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