question stringlengths 3 301 | answer stringlengths 9 26.1k | context list |
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how do headphones create sound by connecting a metal post into a metal housing and sending information through a wire into speakers? | They don't send "information", they send an analog electrical signal. That signal is run through a coil to produce a magnetic field. A small permanent magnet reacts to the field, moving a small speaker cone back and forth to produce sound waves that your ear can detect. | [
"Electrostatic and piezoelectric noise can also become an issue in exotic headphone systems, if the headphones have a relatively high input impedance compared to traditional speakers which have a nominal impedance of 8 Ohms. This is where a careful choice of insulating materials can make a difference. This type of ... |
why do so many people equate abortion with murder when an unwanted baby is often subject to a lifetime of pain and depression due to their parent's inability to care for the child? | Because apparently a life full of suffering and pain that likely ends tragically, is better than not being alive at all. | [
"Unsafe abortion is another major cause of maternal death. According to the World Health Organization in 2009, every eight minutes a woman died from complications arising from unsafe abortions. Complications include hemorrhage, infection, sepsis and genital trauma.\n",
"Unsafe abortions results in complications f... |
if dust in houses is mostly caused by dead human skin cells then why are old abandoned houses always so dusty? | You've been misinformed. Dust is not made up of mainly human skin. It's just that every sample of dust you take inside a home will always contain some human skin.
Dust isade of various small particles. Like fibers from clothing or plants, pollen aggregates, etc. And there's always some dust in the air as can be s... | [
"House dust mites are present indoors wherever humans live. Positive tests for dust mite allergies are extremely common among people with asthma. Dust mites are microscopic arachnids whose primary food is dead human skin cells, but they do not live on living people. They and their feces and other allergens which th... |
I wonder what historians think of Niall Ferguson. | I can only speak about his work on empire - which most historians dismiss as too one-sided and just bad. To put it bluntly, he gives a very distorted view of the British Empire, implying that, on the whole, it was an example of a "benevolent" imperial power who brought progress and modernity to the colonies in contra... | [
"Ferguson was sympathetic to traditional societies, such as the Highlands, for producing courage and loyalty. He criticized commercial society as making men weak, dishonourable and unconcerned for their community. Ferguson has been called \"the father of modern sociology\" for his contributions to the early develop... |
why can't i become the president of the united states (i was born in canada)? | Its the rules
**US Constitution, Article II, Section 1**
No person except a natural born citizen, or a citizen of the United States, at the time of the adoption of this Constitution, shall be eligible to the office of President; neither shall any person be eligible to that office who shall not have attained to the ag... | [
"Every president to date was either a citizen at the adoption of the Constitution in 1789 or born in the United States; of the former group, all except one had two parents with citizenship in what would become the U.S. (Andrew Jackson). Of those in the latter group, every president except two (Chester A. Arthur and... |
what does curiosity do besides taking pictures of mars? | It's got a chemical sniffer, a laser, and a drill. All for looking for chemistry of one form or another that might indicate prior life, or the possibility of future life. And when it meets Spirit and Opportunity they can join to become MegaRover™! | [
"Curiosity is a car-sized rover designed to explore the crater Gale on Mars as part of NASA's Mars Science Laboratory mission (MSL). \"Curiosity\" was launched from Cape Canaveral on November 26, 2011, at 15:02 UTC and landed on Aeolis Palus inside Gale on Mars on August 6, 2012, 05:17 UTC. The Bradbury Landing sit... |
When did a majority of Texans begin speaking English instead of Spanish? | Stephen Austin founded his colony in 1821. At that time, there were fewer than 8,000 Spanish-speaking *tejanos* and perhaps 15,000 Native Americans in Texas. These numbers should be taken with a grain of salt. Many of the Native Americans in Texas were nomadic and lived in Texas for only part of the year (or simply pas... | [
"After Mexico gained independence in 1821, Mexican Texas legally permitted an influx of English-speaking Anglo settlers from the United States (mainly the Southern United States), who within a decade outnumbered Hispanics in Texas, making English as common as Spanish in central and north Texas. After Texas became a... |
What source(s) (primary if possie) could be used as evidence for a paper on the Nazi regieme's efforts to conceal the Holocaust from the public eye? | Nazi-Germany did not try to conceal the holocaust in the east at all. Public mass shootings were common practice. Please read Mark Mazower's Dark Continent for background.
They did try to conceal the holocaust in the west however. Primary evidence could be the administrations of the different Jewish Councils and e.g. ... | [
"The pamphlet alleges that no documentary evidence exists of the Nazi plan to exterminate the Jews. The Crown adduced speeches by Heinrich Himmler, head of the SS, made on October 4, 1943, to his troops in Posen in which he refers to the program of extermination of the Jews. Himmler stated: \"I also want to talk to... |
What is the role of a neutral wire in an A/C? Does the return current in an A/C pass through the live or the neutral wire? | It's the same as the role of neutral wire in DC: in order for the current to move, it has to have a conductor to move through.
In a closed circuit, there is no difference between the live and the neutral wire; the only real difference is that if the circuit is open, touching one will electrocute you (because that's th... | [
"BULLET::::- Neutral wire is the return conductor of a circuit; in building wiring systems, the neutral wire is connected to earth ground at only one point. North American standards state that the neutral is neither switched nor fused except in very narrowly defined circumstances. The neutral is connected to the ce... |
how does glass work to help plants grow? | What do you mean?
Like greenhouses? They let in light and trap heat, allowing plants to grow in colder climates than they could otherwise. | [
"In cultivation this plant needs to be grown in a sharply-drained medium with a low nutrient content, at a minimum temperature of . In the United Kingdom, where it is best grown under glass due to high precipitation, it has gained the Royal Horticultural Society’s Award of Garden Merit.\n",
"Many commercial glass... |
why do red and blonde hair tend to run in the same families if there both recessive genes? | I'm not entirely sure of the allele frequencies of red/blonde hair but I'll continue regardless. By allele frequency I mean the number of people in the population who carry the particular gene variant/allele e.g. blonde/red hair
They must be at sufficiently high frequency that homozygotes (people with two copies of th... | [
"One phenotype (brown/blonde) has a dominant brown allele and a recessive blond allele. A person with a brown allele will have brown hair; a person with no brown alleles will be blond. This explains why two brown-haired parents can produce a blond-haired child. However, this can only be possible if both parent are ... |
how does turning on a lightbulb use more electricity than keeping it running? | There must be an initial surge of energy to get the filament to the proper temperature to produce the light. | [
"Single-pole illuminated switches derive the power to energize their in-built illuminating source (usually, a \"neon\" lamp) from the current passing through the lamp(s) which they control. Such switches work satisfactorily with incandescent lamps, halogen lighting, and non-electronic fluorescent fixtures, because ... |
What led to the development of marine infantry units? | This is a bit of a throughout history question, so it would be best to narrow it down. In broad strokes though there are advantages in having troops who are specialized in certain aspects of warfare, ready to deploy abroad, and under control of your branch of service.
For a lot of history in many places naval warfare... | [
"Marines became prominent during the Pacific War. These soldiers were capable of amphibious warfare on a scale not previously known. As Naval Infantry, both Japanese and American Marines enjoyed the support of naval craft such as battleships, cruisers, and the newly developed aircraft carriers. As with conventional... |
What tactics did viking raid victims come up with to counter the invasions? | First of all this is my first post in r/askhistorians. Apologies if the formatting is incorrect, if I'm honest I'm procrastinating from doing reading on my thesis. I hope it's useful. The answer below focuses primarily on Ireland.
Sources:
Primary:
Annals of Ulster
Life of Blathmacc
Secondary:
Clarke, How... | [
"Viking raids often lacked formation. They have been described as \"bees swarming.\" However, what they lacked in formation they made up with brutality. This naturalistic sense of unconventional warfare is rooted in their lack of organized leadership. These small fleets brutally but effectively scared locals and ma... |
If water conservation is so vital to mammals, why do we pee? Why not transfer toxins into stool and recycle the water? Are there any animals that have evolved to do this? | Safely excreting waste tends to be a balancing act between water and energy. Land animals in non-desert climates tend to urinate in the sense you are familiar with. However, animals in climates in which water is very precious or those which can't carry a lot of water due to weight (birds) use a different method of ge... | [
"Excretion is performed mainly by two small kidneys. In diapsids, uric acid is the main nitrogenous waste product; turtles, like mammals, excrete mainly urea. Unlike the kidneys of mammals and birds, reptile kidneys are unable to produce liquid urine more concentrated than their body fluid. This is because they lac... |
Why do dogs walk in a circle before they lay down? | There are a couple of theories ranging from circling behaviour intended to pad down grass to be more comfortable, to circling in order to judge wind direction and lay nose facing the breeze. There's little conclusive agreement on the true reason however. | [
"Going down with front legs in a bowing position can be an invitation to play if the dog is moving legs from side to side in a playful manner. Just as often, the dog is standing still while bowing and is using the signal to calm someone down. These signals often have double meanings and may be used in many differen... |
In US Presidential election history, has there been cases where the losing candidate completely refused to recognize the results of the election? | Hi there, I'm going to approve this question because it asks about the historical record, but for potential respondents: Please remember that our subreddit rules explicitly forbid both [discussion of current events](_URL_1_) as well as [political discussion/soapboxing](_URL_0_). | [
"The U.S. presidential election occurred on November 2, 2004. However, as in the 2000 U.S. election, the election was too close for a winner to be declared that night. By the next morning, the Republican campaign was declaring a victory while the results in several states remained too close for the media to declare... |
how did columbus communicated with the aztecs if they didn’t speak their language and vise versa? | Columbus didn't communicate with the Aztecs. He never met them.
Hernan Cortes was the man responsible for destroying the Aztec empire.
When Cortes first landed in the Yucatan he met Geronimo de Aguilar, a Spanish Franciscan priest who had survived a shipwreck followed by a period in captivity with the Maya. This pr... | [
"The Aztec language, Nahuatl, was difficult for the Spanish troops stationed in Mexico to pronounce. The common ending \"tl\" sounded like \"te.\" Hernán Cortés' difficulties with the language was evident in the letters he sent, where he writes \"Temistitan\" instead of Tenochtitlan and the tribal god Huitzilopocht... |
Are new planets and stars currently being formed? | There are new planets and stars being formed all the time. And old ones being destroyed. We cannot directly or even indirectly observe most of this due to the distance between our solar system and these other systems and galaxies, but it is happening. In fact everything we are composed of, all of our atoms and those co... | [
"An increasing number of extrasolar planet discoveries are being made with planets in planetary systems known as of . Rare Earth proponents argue life cannot arise outside Sun-like systems. However, some exobiologists have suggested that stars outside this range may give rise to life under the right circumstances; ... |
how integrals can calculate areas? | > how could it ever be accurate?
As you add more rectangles the closer you get to the true answer (because each rectangle will better approximate the curve). The more rectangles you add the closer the "error" is to zero.
Once you have an infinite number of them the error *is* zero. If you know what limits are it's... | [
"In mathematics, a bilinear map is a function combining elements of two vector spaces to yield an element of a third vector space, and is linear in each of its arguments. Matrix multiplication is an example.\n",
"To define the Lebesgue integral requires the formal notion of a measure that, roughly, associates to ... |
Seeking for the translation of what Diogene said to Alexander the Great. | If I understand you right, you're asking for the Greek text? That's in Plutarch's Life of Alexander, 14.3. It looks like this:
> ‘μικρὸν’ εἶπεν, ‘ἀπὸ τοῦ ἡλίου μετάστηθι’
εἶπεν is "he said." So actual quote would be ‘μικρὸν ἀπὸ τοῦ ἡλίου μετάστηθι’
Writing Greek on an American keyboard is a pain in the ass. Ther... | [
"Aristippus was an envoy to Constantinople (1158-1160) when he received from the emperor Manuel I Comnenus a Greek copy of Ptolemy's \"Almagest\". A student of the Schola Medica Salernitana tracked down Aristippus and his copy on Mount Etna (observing an eruption) and proceeded to give a Latin translation. Though t... |
Is there number to acceleration of Universe expansion? | The expansion rate has units of inverse time (for practical reasons it is given as km/(s\*Megaparsec) but that is a length in numerator and denominator). How the expansion changes over time has units of inverse time squared: 1/s^(2).
It can be calculated with the second [Friedmann equation](_URL_0_). In the distant fu... | [
"The definition of \"accelerating expansion\" is that the second time derivative of the cosmic scale factor, formula_2, is positive, which is equivalent to the deceleration parameter, formula_3, being negative. However, note this does not imply that the Hubble parameter is increasing with time. Since the Hubble par... |
how does the same model of device get software updates at different times during a rollout? | Every device had a unique serial number. The device sends its serial number to the update server which uses it to decide whether the device gets an update. | [
"A rolling release is typically implemented using small and frequent updates. However, simply having updates does not automatically mean that a piece of software is using a rolling release cycle; for this, the philosophy of developers must be to work with one code branch, versus discrete versions. When the rolling ... |
do "not for individual sale" warnings on products have any legal binding? | The point of the label is that required legal statements (like nutrition and ingredients) aren't on the individually wrapped servings but rather on the box they came in. These warnings protect the manufacturer from charges that they made items without the required labeling. | [
"To avoid inquiry and punitive action by the United States Federal Trade Commission, cosmeceuticals which do not intend to be regulated as drugs by the FDA are carefully labeled to avoid making statements which would indicate that the product has drug properties. Any such claims made regarding the product must be s... |
why couldn't martin shkreli call the committee of congressmen imbeciles right at the hearing ? can he invoke his 5th amendment and still them to go take a hike? | Just like contempt of court, you can be fined or jailed for contempt of congress.
You have to respect the proceedings even if you do not respect the people. | [
"BULLET::::- Bannon appears at the House Intelligence Committee under subpoena. According to committee members, he answers only 25 questions that were pre-approved by the White House, answering “no” to each, and invokes presidential executive privilege to decline answering further questions. Republican and Democrat... |
why does a knife need to be moved to be sharp? if you touch a knife it's ok, but if you drag your finger down the edge it hurts. | Knives are still sharp straight-on and can cut that way. However, at a microscopic level, even straight-edged knives have tiny teeth. So when you move the edge against the item to be cut, you are actually running a tiny ultra-sharp saw across it.
[Micro photo of a razor's edge can be seen here.](_URL_0_) | [
"BULLET::::- Blade: The blade is the piece of steel that runs down the center of the knife that is secured by both handles when closed. One edge of the blade is sharp and will cut the user if they are not careful, especially when flipping the knife. The other edge, called the swedge, is blunt and won't cut the user... |
If one of an entangled pair of particles is entangled again, what happens to the entangled values in the system? | Three electrons can be maximally entangled as
uuu + ddd
uuu + ddu + dud + udd
uuu + udd + duu + ddd
These are all [GHZ](_URL_0_) states. They're triply entangled, so there are no 'individual states'. Any single measurement of any electron has a 50/50 chance of being up or down. Some measurements of one of the thre... | [
"It is also possible to create entanglement between quantum systems that never directly interacted, through the use of entanglement swapping. Two independently-prepared, identical particles may also be entangled if their wave functions merely spatially overlap, at least partially.\n",
"The scheme relies on two pr... |
as alcohol sterilizes stuff, when we drink booze it kills the good bacteria inside us? | Alcohol is absorbed in your small intestines and subsequently processed and broken down enzymatically by your liver long before it reaches your colon. The colon aka large intestines is where your gut bacteria live predominantly | [
"Several species of the benign bacteria in the intestine use fermentation as a form of anaerobic metabolism. This metabolic reaction produces ethanol as a waste product. Thus, human bodies contain some quantity of alcohol endogenously produced by these bacteria. In rare cases, this can be sufficient to cause \"auto... |
Does capillary action take salt water with it? Why or why not? | Yes, the water drawn up by capillary action would take the soluble salt with it, but you are right that the slightly larger mass of the sodium and chloride ions, compared to water, will make them "climb" slower, and therefore less high.
This is the basis of some types of molecular separation mechanisms/experiments, su... | [
"Normal saline is least irritating to the colon, at the opposite end of the spectrum. Like plain water, it simply functions mechanically to expand the colon, but having a neutral concentration gradient, it neither draws electrolytes from the body, as happens with plain water, nor draws water into the colon, as occu... |
how is it possible for something moving the speed of light to experience no time. | The concept at play here is called Special Relativity; it's one of Einstein's greatest achievements.
The ELI5 is that time slows down for *all* moving objects. You don't notice this on a day to day basis because you're moving *really* slowly; you need to be moving at a nontrivial fraction of the speed of light for th... | [
"According to Albert Einstein's theory of special relativity, \"instantaneous action at a distance\" violates the relativistic upper limit on speed of propagation of information. If one of the interacting objects were to suddenly be displaced from its position, the other object would feel its influence instantaneou... |
Do new scientific discoveries have the same relative significance over time? | It's important that we not mix up science and engineering. There's a lot of cross-pollination, obviously, but they're different things with different goals and means.
Broadly speaking, things can happen in one of two ways. Either we learn something new, then seek (and maybe find, maybe not) ways to apply that knowledg... | [
"Commonly cited examples of multiple independent discovery are the 17th-century independent formulation of calculus by Isaac Newton, Gottfried Wilhelm Leibniz and others, described by A. Rupert Hall; the 18th-century discovery of oxygen by Carl Wilhelm Scheele, Joseph Priestley, Antoine Lavoisier and others; and th... |
the metal thing they press on fighters faces between rounds. | Hits to bony areas usually cause large swelling very quickly. There is no fat/muscle to blunt the force.
The piece you see is actually an "eye iron." It is simply a cold piece of metal. That piece is applied and pressed into the swelling to minimize/reduce it.
It literally "pushes" the swelling down.
The cold hel... | [
"Fighters are covered in full modern produced protective armor, made from steel (or other metal alloy if permitted) made to aesthetically be as close to their historical counterparts as possible. Hits and blows may be aimed at any parts of the body (with the limitations set in the regulations); both wrestling and p... |
what's the deal with all those scammy looking "we buy houses" signs i see at so many intersections? | They buy houses. Why do you think them scammy? | [
"In the early 1980s, the Freelandville Improvement Club decided to put street signs up in town, as they had not had them before then. Oddly enough, there is no current street sign for Happy Street, as anytime one was put up, it was stolen.\n",
"Apart from the front gate structure, all buildings on International S... |
why do skilled nfl athletes still commit penalties? | For a penalty on the body like a facemask it can just be trying to grab their shoulder and missing. So in that instance it is just a case of things happening too fast. Remember, you may be one of the top linebackers in the sport but you're also playing against the best running backs and receivers in the sport.
For so... | [
"In addition to suspensions, Goodell has also fined players for on-field misconduct. For example, on October 19, 2010, the NFL handed out fines to Pittsburgh Steelers linebacker James Harrison, Falcons cornerback Dunta Robinson, and New England Patriots safety Brandon Meriweather after they were involved in controv... |
how bulletproof are dinosaurs? | Well, how does a bullet kill a person? It either damages an organ so badly that it can't work anymore, or it hits a big enough blood vessel that the person bleeds out.
So when you look at the I-Rex, it's basically a huge, scaly mass of muscle. Most bullets probably can't get through all of that dense muscle to actua... | [
"In 2005, the BBC program \"The Truth About Killer Dinosaurs\" used Stan's skull as a model for their hydraulic test of the \"T.rex\"'s bite force and estimated that it exceeded 6.8 tonnes. Additional tests, like those published by Karl T. Bates 2009, used Stan's remains to study the weight distribution of \"T.rex,... |
Is there any evidence that over the counter vitamin D supplements enhance mood? | In the unlikely chance that reduced sun exposure causes a severe Vitamin D deficiency, [you can experience depression](_URL_0_). However, taking supplements to prevent depression isn't quite established. | [
"Vitamin D supplements have been widely marketed for their claimed anticancer properties. Associations have been shown in observational studies between low vitamin D levels and the risk of development of certain cancers. It is unclear, however, if taking additional vitamin D in the diet or as supplements affects th... |
rules about reasonable suspicion vs. probable cause/just cause | Cop here:
Reasonable Suspicion:
An officer reasonably belives a crime *may have* occurred.
For example: An officer is patrolling an area where car break-ins have been a problem. He sees a man in a hoodie (even though it's warm outside) looking into a car window.
He has reasonable suspicion a crime may be occurrin... | [
"Reasonable suspicion is a legal standard of proof in United States law that is less than probable cause, the legal standard for arrests and warrants, but more than an \"inchoate and unparticularized suspicion or 'hunch; it must be based on \"specific and articulable facts\", \"taken together with rational inferenc... |
what role does a director actually play in creating a movie and what are the signs of a poorly directed movie? | The Director of a film (or a play, or a television show episode) is the person responsible for the creative vision of the piece. They create a concept from the script (which may or may not be something concretely found in the script, it may be metaphorical or tangential) and from the concept lead the design and product... | [
"The out-of-work director has a shady past. A witness to his shady past is an aspiring actor, who was subsequently thrown out of the acting circuit. This actor started a catering service for the film unit.\n",
"Since the film director depends on the successful cooperation of many different creative individuals wi... |
What sources are there to suggest that Nero blamed the fire in Rome in 64 CE on Christians? Do we know how he became aware of the movement? Would these suggestions be the earliest independent recognition of Christians as a distinct group in the historical record? | The only source that mentions Nero's blaming of the Christians is Tacitus ([Annals 15.44](_URL_2_)):
> Therefore, to scotch the rumour, Nero substituted as culprits, and punished with the utmost refinements of cruelty, a class of men, loathed for their vices, whom the crowd styled Christians. Christus, the founder o... | [
"The exact cause of the fire remains uncertain, but much of the population of Rome suspected that Emperor Nero had started the fire himself. To divert attention from himself, Nero accused the Christians of starting the fire and persecuted them, making this the first documented confrontation between Christians and t... |
why do so many great mma fighters have multiple losses on their record compared to boxers? | A couple of reasons:
1) MMA is more physically tolling on the body. Even in training, you get hit, get slammed and get submissions put on you. More parts of the body are involved so there are more places to get injured. You are pretty much safe below the belt in boxing and don't have to worry about falling unless you ... | [
"During career mode, all of the attributes are increased by allotted training bonuses. As the boxer progresses from match to match, his statistics start to fade. After 35 fights, his hair turns from normal to grey. Finally after 40 fights, the player is forced to retire even if he or she has never beaten the champi... |
How come soldiers in Mesoamerica and Japan didn't make widespread use of larger shields like in Eurasia? | Define large.
In Mesoamerica, different shield designs were used at various points in time. Ross Hassig talks about changes in Mesoamerican shield design in his book *War and Society in Ancient Mesoamerica*.
The Central Mexican city of Teotihuacan, which fell some 500 years before the Aztec empire arose, appears to ... | [
"During the 19th century, non-industrial cultures with little access to guns were still using war shields. Zulu warriors carried large lightweight shields called Ishlangu made from a single ox hide supported by a wooden spine. This was used in combination with a short spear (assegai) and/or club.\n",
"In Italy, t... |
why, as an adult, i take the same amount of cough syrup or other medicines as a 12 year old when i am heavier and more physically mature? | The dosage is just what they know is safe but still effective generally. If you feel like the recommended dosage is insufficient you can go above. Of course if something goes wrong you can't sue the company because you went against recommendations, and you didn't hear it from me that it should be safe, but for the very... | [
"No good evidence exists for or against the effectiveness of over-the-counter cough medications for reducing coughing in adults or children. Children under 2 years old should not be given any type of cough or cold medicine due to the potential for life-threatening side effects. In addition, according to the America... |
Did WW2 had any cultural impact on arts or music in Europe? | Huge, post modernism was in part a reaction to the world wars and the changes they brought.
In Europe the grief was palpable, imagine if 20% of your population died. It made many artists think that any attempt at meaning or beauty was hopeless and futile in the face of such horror.
It was really shattering to many ... | [
"These works are a few of the examples of some of the musical thought taking place at the turn of the century. However, many European thinkers found fewer resources and more censorship with the incoming Second World War. In response, Charles Seeger helped found the American Society for Comparative Musicology to hou... |
When and why did golf become the default "upper-class hangout/dealmaking" activity? What filled that role before? | In ancient Persia, there was quite an exciting sport that we've been able to reconstruct from artistic depictions, and also the preserved fragments from the ancient Persian *On the art of entertaining officials*, an important handbook for satraps and other royal officials. Whenever a group of royal officials were serio... | [
"Golf became widely popular during the economic bubble, when golf club passes became useful tools for currying favor with corporate executives. Many mid-level salarymen were pressured into taking up golf to participate in golfing events with their superiors. The collapse of the economic bubble led to the closing of... |
When Canada changed its flag, what did they do with all the old ones? | There's never been any legislation covering flag disposal in Canada. The rules of Flag Etiquette are laid out in a [publication by the Department of Canadian Heritage](_URL_0_) and the rule for disposal is pretty vague. It just says that old flags "should be destroyed in a dignified way." But of course that's just the ... | [
"Shortly after Canadian Confederation in 1867, the need for distinctive Canadian flags emerged. The first Canadian flag was that then used as the flag of the Governor General of Canada, a Union Flag with a shield in the centre bearing the quartered arms of Ontario, Quebec, Nova Scotia, and New Brunswick surrounded ... |
if gravity is actually the earth accelerating upwards and the earth is spherical, how can it accelerate upwards in all its surface? | Did you get the bit where it mentioned frames of reference? Because that's what this is all about.
Now, ignore the planet. Ignore all the big stuff around here. Ignore me, ignore you. We're going to talk about two tennis balls in deep space. They're just there, in space - they're not sitting on a table, they're not si... | [
"Gravity acceleration is a vector quantity. In a spherically symmetric Earth, gravity would point directly towards the sphere's centre. As the Earth is slightly flatter, there are consequently slight deviations in the direction of gravity.\n",
"The Earth is massive enough that the pull of gravity created and main... |
what the hell did people think sports concussions were before? | Well the expression for a concussion was usually something like "he got his bell rung" to explain the immediate symptoms of concussion. CTE is different that a concussion though. It is caused by many concussions over time, slowly building, as we understand it now, but is often seen later in life.
So a normal guy racks... | [
"In the 2010s, there has been much controversy about football and brain health, with a number of studies focusing not just on the occasional concussion, but also on the large number of sub-concussive hits. One game in particular in 2012 resulted in five concussions. In 2015, a family sued Pop Warner over the suicid... |
the brain is very important, and very complex and exists in a confined space; given that why is it that tumors in the brain are able to get so large before being noticed? | The common symptoms of brain tumors are just that, common. Headaches, nausea, dizziness, and so on can be caused by a lot of other things and the symptoms themselves can come and go. It's usually once more serious symptoms appear or a pattern of symptoms is recognized that a patient undergo MRI. | [
"The signs and symptoms of brain tumors are broad. People may experience symptoms regardless of whether the tumor is benign (not cancerous) or cancerous. Primary and secondary brain tumors present with similar symptoms, depending on the location, size, and rate of growth of the tumor. For example, larger tumors in ... |
Can anyone tell me about a specific American flag? | hi! it might be worth x-posting this question to the flag aficionados in /r/Vexillology | [
"The flag of the United States of America, often referred to as the American flag or U.S. flag, is the national flag of the United States. It consists of thirteen equal horizontal stripes of red (top and bottom) alternating with white, with a blue rectangle in the canton (referred to specifically as the \"union\") ... |
openoffice vs. libreoffice (vs. microsoft office) | I haven't used OpenOffice since the split, nor MS Office since before then, so I can't comment on the differences between them today. But I can give a little background on the split itself.
OpenOffice used to be run by Sun. [In 2009 Oracle bought Sun](_URL_0_) and maintenance of OpenOffice became less of a prior... | [
"LibreOffice is available for a variety of computing platforms, including Microsoft Windows, macOS, and Linux (including a LibreOffice Viewer for Android), as well as in the form of an online office suite LibreOffice Online. It is the default office suite of most popular Linux distributions. It is the most actively... |
- when you dent your car and the auto body shop uses filler to fill the dent, what are they using? | Polyester resin/putty, sometimes mixed with fiberglass for extra strength. Bondo is a fairly common brand, and other brands are often referred to as "bondo" as a result. | [
"BULLET::::- Body filler: Body filler (or Bondo) is a two-part putty often used to fix dents in automobiles. Case modders use it to fill and sculpt their own creations. When mixed with a paste catalyst the filler hardens in a short period of time and can be sanded, ground or cut to a desired shape. An alternative s... |
is it pitch black in space or is there enough ambient light to see something held in front of you? | Light would be very dim.You would probably be able to make out objects at close range, but not read or see fine details.
[Here's a good r/askscience post on the subject](_URL_0_) | [
"Olafur has been developing various experiments with atmospheric density in exhibition spaces. In \"Room For One Colour\" (1998), a corridor lit by yellow monofrequency tubes, the participants find themselves in a room filled with light that affects the perception of all other colours. Another installation, \"360 d... |
how do cinema projectors have such high quality compared to personal home projectors? | They got a light source (think: a bulb) that is consuming so much energy it's crazy compared to the tiny box you got in your own living room.
And bulbs always create excess heat that needs to be cooled away with active cooling. i.e, fans. Fans are noisy.
But no-one in the cinema cares, because that projector is in it... | [
"Although usually more expensive than film projectors, high-resolution digital projectors offer many advantages over traditional film units. For example, digital projectors contain no moving parts except fans, can be operated remotely, are relatively compact and have no film to break, scratch or change reels of. Th... |
why do chiggers and/or mosquitos seem to bite around a person's joints (e.g. ankle) | In short, evolution or The Fall, depending on your religious flavor or lack thereof.
The most prominent reason is the fact that the blood vessels are very close to the surface of the skin over these areas. Mosquitos have the capacity to sense heat as well as (some speculate) the capacity to sense the blood pumping th... | [
"Chiggers seem to affect warm covered areas of the body more than drier areas. Thus, the bites are often clustered behind the knees, or beneath tight undergarments such as socks, underwear, or brassieres. Areas higher in the body (chest, back, waist-band, and under-arms) are affected more easily in small children t... |
How exactly was Jefferson Davis elected President of the Confederacy? | While a perfectly fine question, more of our Civil War experts are sticking around in [this AMA thread today, so I would suggest you repost it here!](_URL_0_) | [
"Jefferson Davis was named provisional president on February 9, 1861, and assumed similar commander-in-chief responsibilities as would Lincoln; on November 6, 1861 Davis was elected President of the Confederate States of America under the Confederate Constitution. Alexander H. Stephens was appointed as Vice Preside... |
What factors contribute to resting metabolic rate? | First question; not my area
Second question, relating to the first:
[Not much](_URL_0_)
> One study noted that one standard deviation of variance for resting metabolic rate (how many calories are burnt by living) was 5-8%; meaning 1 standard deviation of the population (68%) was within 6-8% of the average metaboli... | [
"T increases the basal metabolic rate and, thus, increases the body's oxygen and energy consumption. The basal metabolic rate is the minimal caloric requirement needed to sustain life in a resting individual. T acts on the majority of tissues within the body, with a few exceptions including the spleen. It increases... |
how is facebook exploiting me? | Basically anything you submit to Facebook becomes their property; Pictures, personal information, everything.
People complain about privacy and then go and spill every single detail of their life to Facebook, thus Facebook is "exploiting" idiots. | [
"Recently, Facebook, knowingly agreed and facilitated a controversial experiment; the experiment blatantly bypassed user privacy and demonstrates the dangers and complex ethical nature of the current networking management system. The \"one week study in January of 2012\" where over 600,000 users were randomly selec... |
where does the sound from the car's blinker actually come from? | It's a relay with a reed switch. Makes noise when activated. They're usually under the dash on the driver's side.
| [
"The result was an engine which idled at 150 rpm and ran with uncanny silence \"the only audible sound made by a Double-Six (if you opened the bonnet and went right up to it) was the almost imperceptible tick as the ignition points opened and the faint breathing of the carburettor\".\n",
"While the car is idling,... |
Why are there distinct lines between the states of matter, instead of just a gradual scale of change? | So, addressing a few misconceptions:
It really isn't a terribly meaningful statement to describe a single molecule as having a temperature. That said, I assume your idea here is that the entire material is in the same "condition" (pressure, temperature, etc).
Next, while it is still "just water", it is incorrect to s... | [
"Classically, states of matter are distinguished by changes in the properties of matter related to external factors such as pressure and temperature. States are usually distinguished by a discontinuity in one of those properties: for example, raising the temperature of ice produces a clear discontinuity at 0 °C as ... |
How and when were all the clocks (time) around the world synced? | As the UK became a maritime nation, boats kept one [chronometer](_URL_0_) on-board so they knew how far away they were from the Greenwich meridian (which is considered to have longitude zero degrees). The chronometer wasn't treated as the actual time, because that was calculated by solar time, depending on where they w... | [
"The 24-hour time system has its origins in the Egyptian astronomical system of decans, and has been used for centuries by scientists, astronomers, navigators, and horologists. In East Asia, time notation was 24-hour before westernization in modern times. Western-made clocks were changed into 12 dual-hours style wh... |
Can anyone name an example of a country that fared poorly as a result of having a really open immigration policy? | Our [subreddit rules](_URL_0_) don't allow "throughout history" questions, so I'm afraid I've had to remove your post. We've found that questions like this end up attracting low effort trivia rather than the in-depth responses people like to see here. If you're interested, I'd encourage you to post a question about imm... | [
"Immigration may be the outcome of problems in the migrants' countries of origin. Open immigration policies and efforts do not address these problems. However, just keeping borders closed does not address them either.\n",
"BULLET::::- \"Migration policy: from control to governance : In the United States and Europ... |
paralysis, specifically if you are paralyzed below the waist, is your genitalia also paralyzed? can a man never have an erection for the rest of his life? | It depends.
Some people are (effectively) paralyzed because of a muscle issue. So, the nerve connection between brain and muscle is still there, but the muscles can't contract when the signal reaches them, or they're too weak to truly move. So, if it's just an issue of "the muscles in the leg no longer function proper... | [
"The onset of paralysis (spastic paraparesis) is sudden and symmetrical and affects the legs more than the arms. The resulting disability is permanent but does not progress. Typically, a patient is standing and walking on the balls of the feet with rigid legs and often with ankle clonus.\n",
"Paralysis can occur ... |
theresa may's announcement of the snap election | May's Blue party think they're currently doing a lot better than Jeremy's Red party. Because the Blue party are in charge of the tree house just now, they've decided to hold the next election earlier than they need to, which is called a 'snap' election.
All the members of the tree house get to vote in whether or not t... | [
"On 18 April 2017, Prime Minister Theresa May announced she would seek an unexpected snap election on Thursday 8 June 2017. Corbyn said he welcomed May's proposal and said his party would support the government's move in the parliamentary vote announced for 19 April. The necessary super-majority of two-thirds was a... |
How serious was the Madagascar plan? | Transcript from the Eichmann trial.
The plan took its final shape during the War. Eichmann admitted that it had been devised and passed on by his Section after consultations and discussions with other authorities. Under this plan all the local inhabitants of Madagascar, about four million persons were to be uprooted, ... | [
"BULLET::::- Madagascar Plan – a scheme devised by the Nazis in 1940 to globally alleviate the perceived Jewish problem by shipping them en-masse to the French colony known as the island of Madagascar. Instead of sending the Jews to Palestine, which the Nazis believed belonged to the Christians and Muslims, the ide... |
how military units get their numbers? like where does 25th id come from? wheres 24th id? | It's largely random. In WWII we had the first, second, and third armies, but then you get reasons like:
-SEAL Team 6: Actually the second SEAL Team, but we wanted the Russians to think we had more.
-112th Airborne: Made up of 2 different units, something like the 50th and 62nd, couldn't decide whose number to take wh... | [
"Wartime service numbers of the Regular Army and the Army of the United States began at 10 000 000 and extended to 19 999 999. A subset of this series was reserved solely for those who had enlisted from recruiting stations outside of the 48 contiguous states of the United States. The first number after the \"ten\" ... |
why should one's beliefs impede another's rights, especially if the other doesn't subscribe to their belief system? | Christians believe being around gay people or being forced to serve them food in their restaurant is the same as "being forced to accept homosexuality". In Christianity, homosexuality is a sin punishable by death, no different from murder.
Also, they believe gay marriage or gay rights are special rights. They beli... | [
"While direct discrimination on grounds of religion or belief is automatically unlawful, the nature of religions or beliefs leads to the conclusion that objective justification for disparate impact is easier. Beliefs often lead adherents to the need to manifest their closely held views, in a way which may conflict ... |
plato's theory of forms and aristotle's criticism to it | Little Kid: "Dad, what's a dog?"
Dad: "Well, we have Buster at home. Buster is a dog."
Little Kid: "Yeah, but what *makes* Buster a dog?"
Dad: "Well, he walks on four legs and is covered in fur."
Little Kid: "Yeah, but so does our cat Oscar."
Dad: "Yeah... well, Buster barks."
Little Kid: "But bears walk on four ... | [
"Aristotle argued at length against many aspects of Plato's forms, creating his own doctrine of hylomorphism wherein form and matter coexist. Ultimately however, Aristotle's aim was to perfect a theory of forms, rather than to reject it. Although Aristotle strongly rejected the independent existence Plato attribute... |
why are videogame consoles and other electronics arranged in rectangular prisms rather than cubes? | They're based around circuit boards which tend to be flat and not square. Making a cube would either result in a *giant* cube, forcing you to make your circuit board really tiny or splitting the electronics into multiple square boards & adding some sort of interconnect between them, none of which are ideal solutions... | [
"In three-dimensional variants, the playing field is a cube (containing smaller cubes) instead of a rectangle, and the player has the ability to rotate the cube. \"Cubes\" for iPhone OS uses this approach.\n",
"In the fields of computer and video games and pixel art, the technique has become popular because of th... |
Serious: Is the increase in detection and diagnosis of all Cancers in any way related to the increased levels of radioactive materials in circulation globally? | In short: no. Only a [small fraction of cancers](_URL_0_) is attributable to radiation.
There are several reasons that cancer is more prevalent (or appears more prevalent) in recent years.
1) Age is the #1 risk factor for cancer. In other words, the older you are, the more likely you are to develop it. This means ... | [
"There has been considerable research done on the effect of low-level radiation on humans. Debate on the applicability of Linear no-threshold model versus Radiation hormesis and other competing models continues, however, the predicted low rate of cancer with low dose means that large sample sizes are required in or... |
why do veins swell when you constrict your blood flow? | Blood flows out from your heart along arteries, and back to the heart along veins. Blood pressure is very high in the arteries, and low in the veins - it's the drop in pressure that carries it through your circulatory system.
So, grab your arm above the elbow, and what's happening? You're constricting the whole area, ... | [
"Veins may become temporarily blocked if the internal lining of the vein swells in response to repeated injury or irritation. This may be caused by the needle, the substance injected, or donating plasma. Once the swelling subsides, the circulation will often become re-established.\n",
"When blood vessels dilate, ... |
what is border adjustment and how will it let trump force mexico to pay for the wall? | I'm not an expert. But as I understood it, the border adjustment simply means import/export toll (I don't know the English word; I mean the fee you or a company has to pay to be allowed to transport goods to another country) is changed. Less import taxes for US Companies, and more export taxes for Foreign (Mexican) com... | [
"Trump repeatedly said that Mexico will pay for the construction of the border wall, but did not explain how the U.S. government would compel Mexico to do so. Trump stated that \"there will be a payment; it will be in a form, perhaps a complicated form\". The Mexican government has rejected Trump's statements and h... |
Why isn't matter evenly distributed across the universe? | It is, just not on small scales. The basic structure of the universe on large scales is galactic superclusters, to clusters, to galaxies, to stars. At supercluster level, the universe is very evenly distributed.
[this](_URL_0_) link gave a good description of how the local distributions came about.
To paraphrase, mat... | [
"As a matter of fact, the great majority of ordinary matter in the universe is unseen, since visible stars and gas inside galaxies and clusters account for less than 10 per cent of the ordinary matter contribution to the mass–energy density of the universe.\n",
"The remaining 4.9% of the mass–energy of the Univer... |
When And Why Did Children's Books Emerge? | I did an overview of pretty much the entire history of children's literature in [this answer about the rise of YA lit](_URL_0_), though I skirt around spending a lot of time doing in-depth discussion surrounding the beginnings of children's literature. If you're not satisfied with that answer and would like me to go mo... | [
"Children's literature has been a part of American culture since Europeans first settled in America. The earliest books were used as tools to instill self-control in children and preach a life of morality in Puritan society. Eighteenth-century American youth began to shift away from the social upbringing of its Eur... |
the rick perry indictment | Lehmberg is an elected district attorney. As such, she cannot be fired directly by Governor Perry. Lehmberg was charged with a DWI back in 2013, did some jail time, and successfully defended her position in a civil suit. Governor Perry does not want Lehmberg to remain in office, so he threatened to veto $7.5 M in fu... | [
"On August 15, 2014, Perry was indicted by a Travis County grand jury. The first charge of the indictment was abuse of official capacity, which has since been ruled unconstitutional, for threatening to veto $7.5 million in funding for the Public Integrity Unit, a state public corruption prosecutors department. The ... |
how do shows like last week tonight identify clips for a clip montage? | Studios have library / archive services that will sell you clips to use. For example, [NBCUniversal Archives] (_URL_0_) has clips from their news shows.
| [
"Footage from the show is usually edited from an entertainment perspective that relies on \"suspense building mechanisms\" such as brief segments involving team members becoming agitated or startled, asserting they have seen or heard something of interest and then followed by a sudden cut to a commercial break. Con... |
How did early films get copied and mass-produced? | While I can't give a good answer, I can say what I would do if I had their technology.
I would take an unexposed reel and match it up with the film's reel. Laying the two strips over one another, shine a light through the original and then through the new film. The original film will filter the light that will the... | [
"The potential of movies as long term sources of revenue was unknown to early movie industry executives. Films were made quickly, sent into distribution channels and mostly forgotten soon after their first runs. Surviving prints were wontedly stored haphazardly, if at all. Early film stock was chemically volatile a... |
how does a thermal explosion cause a human to get knocked back, as often seen in action movies? | Movies aren't always representative of real life. Action movies even less so.
Of course, it's possible for an explosion to knock people back. Because of the rapidity with which explosion take place, they almost always create a shock wave. The problem with being knocked back with the shockwave from a thermal explosion,... | [
"The shock wave from an explosion can be reflected by an inversion layer in much the same way as it bounces off the ground in an air-burst and can cause additional damage as a result. This phenomenon killed three people in the Soviet RDS-37 nuclear test when a building collapsed.\n",
"A thermal wave is created by... |
how broadcasters get such good sound of professional athletes while they are on the field. | The use [parabolic microphones](_URL_0_). They put a directional microphone at the focal point of a big bowl, and it makes it ultrasensitive towards sounds from a particular spot. | [
"In sports broadcasting, a sports commentator (also known as sports announcer, sportscaster or play-by-play announcer) gives a running commentary of a game or event in real time, usually during a live broadcast, traditionally delivered in the historical present tense. Radio was the first medium for sports broadcast... |
How does density affect the speed of seismic waves through the Earth? | Waves travel more slowly through denser material. A lot of people have this misconception because, for example, sound travels faster in water than air, and faster in steel than water. But actually the increasing density is impeding the speed of sound. It's the increased stiffness (elastic modulus) of these materials th... | [
"The density profile through Earth is determined by the velocity of seismic waves. Density increases progressively in each layer largely due to compression of the rock at increased depths. Abrupt changes in density occur where the material composition changes. \n",
"The propagation velocity of seismic waves depen... |
Historians, what was Christmas like during the American Revolution? | Christmas night 1776 General Washington crossed the Delaware river to mount a surprise attack on Hessian mercenaries in Trenton New Jersey. Not the heart warming story you were looking for but a Christmas story none the less.
Edit:
The following year Washington's Army was at winter quarters in Valley Forge where rough... | [
"In the aftermath of the American Civil War, Christmas became the festival highpoint of the American calendar. The day became a Federal holiday in 1870 under President Ulysses S. Grant in an attempt to unite north and south. During the 19th century, the Puritan hostility to Christmas gradually relaxed. In the late ... |
What was the result of the location of pangea, and the resulting difference in earth's centermass? | Firstly, Pangea was only the [most recent](_URL_0_) of at least 6 supercontinents that have existed in Earth's history. It formed about 300 million years ago, and started breaking up about 175 million years ago.
Secondly, as far as mass of the planet is concerned, the vast, vast majority is contained in the mantle and... | [
"Pangea broke apart after 70 million years. The supercontinent was torn apart through fragmentation, which is where parts of the main landmass would break off in stages. There were two main events that led to the dispersal of Pangea. The first was a passive rifting event that occurred in the Triassic period. This r... |
Does fungus build up a resistance to treatment like bacteria does? | What kind of anti-fungal treatment do you mean? Fungi can certainly evolve resistance to [agricultural fungicides](_URL_3_) but it sounds like you're more interested in [antifungal medication](_URL_4_) to which fungi have also evolved resistance: [1](_URL_2_) [2](_URL_0_) [3](_URL_1_). It seems as if whoever said that ... | [
"Development of fungal resistance can be prevented by not using cyproconazole \"repeatedly alone in the same season\" or by not using it late in the infection, that is, curatively. Fungi can develop resistance if the same fungicide is used repeatedly or when fungicides with the same mode of action are repeatedly.(p... |
What is more expensive - mail or plate armour? | At least in the Burgundian accounts, the mail armour is cheaper (in general) as the plate armour, but some very high grade mail armour could be a lot more expansive than low quality plates armour. For exemple, a full plate armour could cost between 37£ 3 s and 76£ 10s, a mail shirt, between 5£ 13s and 50£, a higher pri... | [
"By the 14th century, plate armour was commonly used to supplement mail. Eventually mail was supplanted by plate for the most part, as it provided greater protection against windlass crossbows, bludgeoning weapons, and lance charges. However, mail was still widely used by many soldiers as well as brigandines and pa... |
How long does it take for a cell to travel through your body? | [This page](_URL_2_) says that in a 120-day span, it will travel the body about 75,000 times. That gives you a bit over [2 minutes](_URL_0_). However, it will flow at different rates depending on the type of blood vessel it is in (see [here](_URL_3_)) and probably spends some time moving through your heart and also I t... | [
"Interphase is the phase of the cell cycle in which a typical cell spends most of its life. If, we consider that the total event (interphase and mitotic cell division) take place about 24 hrs. then the interphase is of 23 hrs. Interphase can also be thought of as lasting for 90% of the cell's life, while Mitosis us... |
How are multiple sounds transmitted through gases simultaneously? | One way of thinking of it is that you only hear *one* sound, which is the sum of all the individual sounds. If you look at a sound waveform, it's a single line travelling up and down as air pressure changes. A steady tone has a very simple wave (a sine wave). In fact any sound can be considered to be made up of sine wa... | [
"In low molecular weight gases such as helium, sound propagates faster as compared to heavier gases such as xenon. For monatomic gases, the speed of sound is about 75% of the mean speed that the atoms move in that gas.\n",
"In a non-dispersive medium, the speed of sound is independent of sound frequency, so the s... |
What is happening on the cellular level when you rub lotion into your skin, and why is it good for you? | When you say lotion you can mean one of a few different things. Products known as [emollients](_URL_0_) are lipid (fat) heavy solutions that restore barrier function to disrupted skin. Another sub-class of "lotions" are humectants, which hydrate the skin by trapping water. Generally speaking, the lotion (vehicle) has l... | [
"Absorption through the skin is increased when lotions are applied and then covered with an occlusive layer, when they are applied to large areas of the body, or when they are applied to damaged or broken skin.\n",
"All topical products, including lotions, can result in the percutaneous (through the skin) absorpt... |
why is it so hard to find alcohol that doesn't taste...like alcohol? you'd think someone would make a killing off of 40% koolaid-flavoured alcohol. | Haven't you ever heard of flavored vodka? Tastes like candy. Especially caramel vodka, thats some good stuff. | [
"Excessive concentrations of some alcohols other than ethanol may cause off-flavors, sometimes described as \"spicy\", \"hot\", or \"solvent-like\". Some beverages, such as rum, whisky (especially Bourbon), incompletely rectified vodka (e.g. Siwucha), and traditional ales and ciders, are expected to have relatively... |
does true randomness exist in the universe? if i replayed the universe exactly the same from the start, would it be exactly the same? | Does true randomness exist in the universe?-Yes. At a quantum level randomness happens all the time. Would the universe be exactly the same if we re-ran it? Probably not, if our quantum theories are correct, although not everyone agrees. Whether we could notice the difference is anyone's guess. | [
"Randomness can be seen as conflicting with the deterministic ideas of some religions, such as those where the universe is created by an omniscient deity who is aware of all past and future events. If the universe is regarded to have a purpose, then randomness can be seen as impossible. This is one of the rationale... |
How did tribes like the Seminole in the Everglades deal with alligators? | To start out with, by the time the Seminoles started settling Florida, they already had guns. So lets turn the clock back a bit more. For thousands of years, alligators were on the menu for people living in Florida. They weren't really a common meal, of course, but their bones do show in trash middens alongside other g... | [
"Alligator boats were a type of amphibious vehicle used in the forestry industry throughout Ontario, Quebec, the Maritime provinces of Canada and the northern United States from the mid-19th century to the beginning of the 20th century. These boats were so named because of their ability to travel between lakes by p... |
how are wild plants domesticated? | It's a very very long process, where farmers basically just breed plants with traits they like, in an effort to make those traits more prevalent over time. | [
"The process of domestication of wild plants cannot be described with any precision. However, Bruce D. Smith and other scholars have pointed out that three of the domesticates (chenopods, \"I. annua\", and \"C. pepo\") were plants that thrived in disturbed soils in river valleys. In the aftermath of a flood, in whi... |
why does my heart rate drop when i exhale? | It's called sinus arrhythmia, and it's perfectly normal and benign, especially in young people. I have it too.
I'm a little fuzzy on the details, but I believe it's because the expansion of your lungs as you inhale puts pressure on a nerve that controls heart rate. | [
"During exhalation, the diaphragm relaxes, moving upward, and decreases the size of the chest cavity, causing an increase in intrathoracic pressure. This increase in pressure inhibits venous return to the heart resulting in both reduced atrial expansion and reduced activation of baroreceptors. This relieves the sup... |
the difference between unlawful and illegal. | They're pretty much interchangeable. You might define "illegal" as "forbidden by the law" and "unlawful" as "not permitted by the law", but they boil down to the same thing. "Illegal" also tends to be used more for criminal law, while a civil wrong is more likely to be described as unlawful, but that's not a clear cut ... | [
"In US law, the term illegal \"per se\" means that the act is inherently illegal. Thus, an act is illegal without extrinsic proof of any surrounding circumstances such as lack of \"scienter\" (knowledge) or other defenses. Acts are made illegal \"per se\" by statute, constitution or case law.\n",
"Natural-law the... |
lasers and mirrors | If a mirror reflects 90% if light that means it absorbs 10% of the light. If 10% of a laser is enough to burn a thing then the mirror burns. There is no 100% reflective mirrors. | [
"BULLET::::- Active mirrors are mirrors that amplify the light they reflect. They are used to make disk lasers. The amplification is typically over a narrow range of wavelengths, and requires an external source of power.\n",
"Light from the medium, produced by spontaneous emission, is reflected by the mirrors bac... |
why do home thermostats have a "heat/ cool" switch? why can't you simply set a range and have it automatically determine whether to use the ac or the heater? | There are actually thermostats that have an 'auto' mode that does switch from heat to cool and vice versa. Typically, only higher end thermostats have this, though. This is because it takes more advanced temperature sensors to allow an 'auto' function to work.
Say it's summer and you have the thermostat set to 'cool... | [
"A home thermostat is an example of a closed control loop: It constantly measures the current room temperature and compares this to a desired user-defined set point and controls a heater and/or air conditioner to increase or decrease the temperature to meet the desired set point. A simple (low-cost, cheap) thermost... |
why are data caps for mobile phones still so small? | Phone companies are greedy so they set data limits low to either a) make you use less of their product than you normally would or b) pay more for using your natural level of usage. | [
"Because of its nature data at rest is of increasing concern to businesses, government agencies and other institutions. Mobile devices are often subject to specific security protocols to protect data at rest from unauthorised access when lost or stolen and there is an increasing recognition that database management... |
Does the wobble of our sun caused by Jupiter's gravity effect the weather on Earth? | Jupiter's gravity does affect the climate on Earth but it's over many thousands of years. The variations in Earth's axial tilt, orbital obliquity, etc caused by Jupiter are called the Milankovich cycles and are associated with ice ages. As for the 12 year orbit of the Sun/Jupiter system...the 11 year sunspot cycle like... | [
"The Jupiter Effect is a 1974 book by John Gribbin and Stephen Plagemann, in which the authors predicted that an alignment of the planets of the Solar System would create a number of catastrophes, including a great earthquake on the San Andreas Fault, on March 10, 1982. The book became a best-seller. The predicted ... |
How different is breast milk to formula in terms of the baby's health? | Please remember that this is /r/askscience. While it may be tempting to share your own experiences as a parent, this forum is for a discussion of science. **Please refrain from sharing your own experiences or speculation/guesses.**
There is a lot of research on this topic, so please make sure to use scientific sourc... | [
"Though it now is almost universally prescribed, in some countries in the 1950s the practice of breastfeeding went through a period where it was out of vogue and the use of infant formula was considered superior to breast milk. However, it is now universally recognized that there is no commercial formula that can e... |
Rhodesia & NIBMAR | The policy of 'No Independence Before Majority Rule' came out of the September 1966 meeting of the Commonwealth of Nations. At that meeting, Commonwealth members from the Caribbean, Asia and Africa (minus Southern Rhodesia) caucused together and proposed that the Commonwealth position should be No Independence Before M... | [
"Rhodesians made up an integral component of the Long Range Desert Group (LRDG), a mechanised reconnaissance and raiding unit formed in North Africa in 1940 to operate behind enemy lines. Initially made up of New Zealanders, the unit's first British and Rhodesian members joined in November 1940. It was reorganised ... |
Is analytic continuation of the Riemann-Zeta function more than just a reflection over a vertical line? | It's almost a reflection about the line Re(s)=1/2 (the critical line), but not exactly. If it were a reflection, then if s were a point to the left of this line, its value there would be equal to the value of the point exactly opposite on the right side of the line, and this point is 1-s. That is, we would have Z(s) = ... | [
"BULLET::::- The calculations in show that the zeros of the zeta function behave very much like the eigenvalues of a random Hermitian matrix, suggesting that they are the eigenvalues of some self-adjoint operator, which would imply the Riemann hypothesis. However all attempts to find such an operator have failed.\n... |
what do underwriters for insurance companies do? | Underwriters are the people actually taking on responsibility for the insurance claim; the people who will actually pay.
In a lot of cases this is the same company, but if for instance you use an insurance **broker**, that's where things would be different, because they would search around for the best company for wh... | [
"BULLET::::- Insurance underwriting - Personal lines insurance underwriters actually underwrite insurance for individuals, a service still offered primarily through agents, insurance brokers, and stock brokers. Underwriters may also offer similar commercial lines of coverage for businesses. Activities include insur... |
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