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benjamin libet's free will experiment. | I'll try. Libet instructed his subjects to make a small wrist movement whenever they felt like it. He also instructed them to note the time on a clock regarding the moment they first became aware of deciding when to move. Of course they were all wired up to have their brains activity recorded.
Turns out that Libet consistently found an electrical spike called the readiness potential (RP) 200ms before the subjects reported becoming aware of their decision to move. This strongly suggests that at least some of what we assume to be free and conscious decisions are actually pre-decided unconsciously.
Libet himself didn't interpret the results as a refutation of free will, and has argued against those who have. He believes that we have free will in the form of veto power over unconsciously directed decisions. Critics say that even this "free won't" is nevertheless a product of unconscious activity and effectively the equivalent of free will.
Others have followed up on Libet's work and have found even greater lag times between the RP spikes and subjects' conscious awareness of having made a decision. | [
"In 2004, Conway and Simon B. Kochen, another Princeton mathematician, proved the free will theorem, a startling version of the 'no hidden variables' principle of quantum mechanics. It states that given certain conditions, if an experimenter can freely decide what quantities to measure in a particular experiment, t... |
Are rocket launches (to space) generally straight or curved? | As I understand it, getting something into orbit is more about going sideways really fast than going up really high. You have to go a bit up to get above the atmosphere but then go mad fast in the same direction as the Earth is spinning.. That spin gives a nice like speed boost.
Put those 2 needs together and you get a curved flight path. | [
"The diagram illustrates three cases. The middle rocket shows the straight-line flight configuration in which the direction of thrust is along the center line of the rocket and through the center of gravity of the rocket. On the rocket at the left, the nozzle has been deflected to the left and the thrust line is no... |
Need access to archives, what should I do? | I'm a librarian and an archivist. First off: contact your library. If librarians only advised on issues we were personally subject experts on we'd have to shut down right now. You think I answer questions about eunuchs all day? Of course not. Librarians are familiar with how to find anything, that's what we're trained on, not subject expertise. I can just as easily answer your question as help someone find car repair manuals for a 1988 Honda Accord, having no expertise in either, it is the same essential task to us. Also you're almost certainly going to need ILL with this, since it sounds like your school doesn't support a strong East Asian program? And you'll probably need help working with ILL because we don't typically teach it to freshman library instructional classes, usually just grad students.
Second: this is way too much for a freshman, slow your roll! No one expects a freshman to be churning out original archival research in a language they don't fluently read! There would be way less college graduates if so. I do archives instructionals with freshman and they typically are me presenting a single document (in English) carefully selected to relate to their classroom topics, and a worksheet with questions like "Who wrote this document? Who did the writers intend to read or use this document?" etc. [Talking this level](_URL_1_) is what I expect from a freshman, as an archivist working with freshmen.
What you can reasonably use at your level (though this is somewhat advanced for a freshman, but not crazy advanced) is translated published primary source collections. [Here is a good guide to what these are and how to find them.](_URL_0_) The main words to use when searching are "sources" and "documents." [This example search turns up what you should be looking for.](_URL_2_) | [
"These online archives serve many needs, such as storing the scholarly works of university authors; preserving information from specific research disciplines; and disseminating new scholarly work quickly, without a lengthy publication process.\n",
"Your Archives is a wiki for the National Archives on-line communi... |
if salt is so bad for cars, why do we use it on the roads? | salt is good for not dying in car crashes and car crashes are worse for cars then salt.
Some places use other things, but salt is really cheap compared to most alternatives, although sand is pretty good. | [
"As a result of Canada's icy winters, salt is needed in order to deice slippery roads. The primary ingredient of road salt is sodium chloride. Road salt, while helping cars and people to gain traction in the winter, can have serious consequences for soil. As National Geographic found, \"Road salt can pollute soil a... |
How could have people found and colonized islands in the Pacific almost 2000 years ago while it have took much more effort to do the same with the America? | 2 things:
To this day, the colonisation of the pacific islands stands as one of the most brillant feats of navigation. The time scale you describe speaks far more to the excellence and motivation of the Pacific islanders as navigators than it does to any ability of the Europeans. Cook established through his first contacts with Pacific islanders that they could navigate extraordinarily accurately using simply the stars and swells on the ocean as guides. The use of wave patterns in particular is not unlike the way waterstriders use triangulation to locate floating objects. It seems Pacific islanders used similar methods to locate new islands.
2 - There were other Europeans between the Vikings and Columbus, such as the Basque. | [
"The aim of the expeditions was to prove that the Pacific Islands could have been populated by migrations from South America in the centuries before the Spanish Conquistadors arrived. Alsar maintained that ancient mariners knew the Pacific currents and winds as well as modern humans know road maps.\n",
"Spaniards... |
how can websites display an overloaded page if they're overloaded? | Modern websites, especially popular ones are not a standalone computer running a webserver. They're usually part of a full network of servers.
Front end web servers that receive a request from users. Web caches that store commonly requested pages and data. Databases and file servers for a lot of the back end data.
So front end webserver can be programmed to follow this sequence:
1. check if page is available in the web cache, use that if possible.
2. if web cache is unavailable or slow to respond query database and file server, use that if possible
3. Fall back to an error page of "overloaded" or "down for maintenance" | [
"Consider a web browser which attempts to load a page while the network is unavailable. The browser will receive an error code indicating the problem, and may display this error message to the user in place of the requested page. However, it is incorrect for the browser to place the error message in the page cache,... |
what is stopping me from taking a loan out to pay another loan and then taking a loan out to pay that loan? | This is commonly done and is sometimes called *rolling over* a loan. The problem is that the amount due will keep increasing due to interest charge, and eventually it will be so large that no one will be willing to loan you that much. | [
"Borrowers can either opt for a short-term relief by having their mortgage payment suspended for a short period of time (known as forbearance in the U.S.), or they can apply for reduced payments over the life of the loan’s term (known as loan modification in the U.S.). Lenders are required to give a particular reas... |
why do scuba divers go into the water backwards instead of front first? | If they don't go back first, they go feet first. Both for several reasons.
1. Out of the water, the tank is **heavy**. Imagine doing a belly flop while wearing a backpack full of cinder blocks. You hit the water, then the pack hits you. Ouch.
2. Hitting the water face first means you get the mask smacked into your face. Ouch again.
3. Some kinds of SCUBA gear will have bits extending behind your head. Going face first means you have a good chance of smacking the back of your head on them. Not fun.
4. When you hit the water, you are less concerned about landing on the guy that is already in the water than you are about the next guy in line landing on *you*. Going back first means you can see what's going on above you and move if needed.
5. Lastly, sometimes shit happens and you need to quickly ditch your gear. If you are face down, you have to get out from under the stuff after you undo the buckles, risking getting something getting caught in a stray loop. Face up means everything is below you, thus much less risk of getting snagged. | [
"Because of the direction of thrust is mostly in line with the diver, or slightly upwards, it is suitable for situations where disturbing the silt on the bottom can cause dramatic loss in visibility, such as inside wrecks and caves, and at any other time when the diver needs to swim close to a silty substrate. Some... |
how is it that we are still discovering galaxies that are relatively close to our own galaxy when we’ve discovered millions of galaxies that are much farther away? | So... look at the sky.
Now. With your hand make a circle
Now through that circle, focus on only the sky you can see in the perimeters of your hand. Imagine zooming in almost endlessly, finding millions of different cosmic clusters just in those small confines.
Now pick another random part of sky. Do it again and voila! You found a new galaxy. | [
"BULLET::::- Astronomers report that the most distant known galaxy, UDFj-39546284, is now estimated to be even further away than previously believed. The galaxy, which is estimated to have formed around \"380 million years\" after the Big Bang (about 13.75 billion years ago), is approximately 13.37 billion light ye... |
do animals have body clock? | Well seeing as how humans are mammals. And mammals are animals. And we have have one.
Yes other animals do too | [
"Most animals and other organisms have \"built-in clocks\" in their brains that regulate the timing of biological processes and daily behavior. These \"clocks\" are known as circadian rhythms. They allow maintenance of these processes and behaviors relative to the 24-hour day/night cycle in nature. Although these r... |
why does your appetite decrease in extreme heat? | Your metabolism's job is to regulate the temperature of your body. "Metabolizing" food is basically like setting it on fire in your body and using the heat for energy.
In the extreme heat, your body temperature is already high. So your body doesn't burn the energy it has as aggressively (your metabolism slows down) so that you don't overheat. This decreases your appetite.
It's also why you have less energy and feel wiped out after a hot day. You still needed that energy, but your body converted less to avoid overheating. Basically put you in low power mode. | [
"BULLET::::4. Thermostatic hypothesis: According to this hypothesis, a decrease in body temperature below a given set-point stimulates appetite, whereas an increase above the set-point inhibits appetite.\n",
"The cessation of a desire to eat after a meal \"satiation\" is likely to be due to different processes an... |
what exactly is petrified wood and how does it become petrified? | It's when it's turned to stone after millions of years. The wood becomes buried underground where it's preserved because of the lack of oxygen, and as water flows through the ground on top, the minerals enter the wood and replace the organic material. Eventually all of the organic material is replaced by mineral, and the wood is now stone which has kept its original structure. | [
"Petrified wood are fossils of wood that have turned to stone through the process of permineralization. All organic materials are replaced with minerals while maintaining the original structure of the wood.\n",
"Petrified wood (from the Latin root \"petro\" meaning \"rock\" or \"stone\"; literally \"wood turned i... |
How close to the original texts is the New Testament today? | I guess I'd tackle this question by first addressing what "in the texts today" means. Biblical versions in modern languages are translated from what's called *critical editions* of the NT. A critical edition is produced by taking the earliest manuscripts of the NT we have, comparing their texts and--through certain (quite complicated and contentious) processes--determining the common "archetype" for these manuscripts, which is thought to be close(r) to the original texts. (Big caveat on the term "original text" [here](_URL_0_), if you're looking to get waaay into some hardcore stuff.).
Much more could be said about this process, but the salient point is that the "texts today" are really based on manuscripts (or reconstructed texts) from the 2nd-5th centuries--which doesn't lie *too* far away from the time of their original composition. (Though there are many other texts--for example the Homeric works, etc.--for which the earliest manuscripts are ~1,500+ years after the time of their original composition, and yet are almost certainly very close to the "original" texts.)
_____
The question is then this: if we can reconstruct, with good confidence, what the NT texts looked like in, say, the (mid-to-late) 2nd century, *how do we know that the texts weren't changed in the time between their original composition (in the mid-1st to early 2nd century) and then*?
There are some general methods for determining this. One of the main ways in that interpolations into the texts are often times *disruptive* to their style/vocabulary/syntax/flow, etc. Perhaps if one were unscrupulous enough to actually attempt to alter these texts, they were at the same time careless enough to not spend a lot of time making sure it wasn't an obvious intrusion into these elements of the text.
But there are other cases in which there is no consensus as to whether something is a secondary interpolation or not. Some of the most hotly-debated passages here include things like 1 Corinthians 14:34-35 and 2 Corinthians 6:14-7:1. People can be trigger-happy about proposed interpolations, though; and you can find discussion/analysis of tons of proposed interpolations in books like William Walker's *Interpolations in the Pauline Letters*.
____
Finally: there are a few instances in the Hebrew Bible where what we think of today as a single "book" was originally a shorter original work, with later redactors then taking another (later) related work and adding it to the original one, so that it's almost like a "collection" of books within a single one. For example, in the Wiki article for the book of Isaiah, you can find this:
> The scholarly consensus which held sway through most of the 20th century saw three separate collections of oracles: Proto-Isaiah (chapters 1–39), containing the words of Isaiah; Deutero-Isaiah (chapters 40–55), the work of an anonymous 6th-century author writing during the Exile; and Trito-Isaiah (chapters 56–66), composed after the return from exile. While one part of the consensus still holds – virtually no one maintains that the entire book, or even most of it, was written by one person – this perception of Isaiah as made up of three rather distinct sections underwent a radical challenge in the last quarter of the 20th century.
(The book of Enoch is another great example of this, with the divisions between the separate works that comprise the "one" book even more obvious.)
However, proposals of a similar process taking place in the NT have not held large sway. Yes, it's virtually uncontested that, say, the author of the gospel of Matthew copied large sections of the gospel of Mark; but this is merely a *utilization of another source*--it's not like Matthew is just Mark + another autonomous work tacked onto it.
Perhaps the most comparable thing in the NT is in the composite nature of things like the [Second Epistle to the Corinthians](_URL_1_): that this "single" epistle was actually several separate letters that were then compiled into one "collection." | [
"There is no scholarly consensus on the date of composition of the latest New Testament texts. Conservative scholars John A. T. Robinson, Dan Wallace, and William F. Albright dated all the books of the New Testament before 70 AD. But most scholars date some New Testament texts much later than this. For example, Ric... |
Generation War or Our Mothers Our Fathers | Disclaimer: I liked Generation War, for what it was, a piece of entertainment; and fairly decent combat scenes.
Now, with that out of the way, I do agree there needed to be a huge suspension of disbelief. My eyebrows merged with my hairline when the 'Token Jewish Friend' made his first appearance. This was unheard of; the Series begins prior to Barbarossa so you wouldn't risk much more than negative attention from the regime at that time, but association or hiding of Jewish persons later on would be a death sentence. It wasn't just farfetched it was insulting; It *really* did seem like it was an alleviation of German guilt.
Others have taken issue with this as well. Poland did not take well to the depiction of the RKA. There has been arguments that there was heavy anti-semitism before and after WWII in Poland, but the series depicts them as so *collectively* anti semitic that it accomplishes nothing more but to say "See look, we weren't the only ones!" Its intellectually dishonest, and the Polish Newspaper "The Catholic Weekly" wrote a [good review](_URL_0_) (Use a good translator there) that echoes these sentiments and has some nuggets of info on the actual RK.
If I could inject my opinion here; I don't think the producers of Generation War meant to deliberately alleviate German guilt, however, based on how it was recieved abroad and the general touchiness of the subject, it certainly appeared that way. As a piece of entertainment, *of course* you need to be able to sympathize, empathize and relate to the main characters - so they become essentially decent people. The 5 main characters are meant to represent ''the typical Germans'' however, so its one big foggy looking-glass. | [
"Generation War (, literally \"Our mothers, our fathers\") is a German World War II TV miniseries in three parts. It was commissioned by public broadcasting organization ZDF, produced by the UFA subsidiary TeamWorx, and first aired in Germany and Austria in March 2013. The series tells the story of five German frie... |
In the Middle Ages, in times of war, how likely would princes participate with their father? | I can specify for Early Medieval rather than necessarily High Medieval, although there is some considerable overlap. In essence, the answer boils down to the fundamental values of medieval kingship. A medieval king has three major responsibilities: to defend his people, to justly uphold the law, and to maintain the faith. In particular when dealing with early medieval kingship, such as in Anglo-Saxon England, it was vitally important for a king to be seen as a brave and competent military leader. This is why, for example, Harold Godwinson fights on foot in the middle of the battle line at Hastings in 1066.
It may seem dangerous to have your heirs alongside you in a battle, but symbolically, it could almost be *more* dangerous for them to be seen to be avoiding battle, and thus be weak. The *Anglo-Saxon Chronicle* portrays a long tradition of heirs taking part in conflict, either alongside their fathers and brothers, or often leading armies independently. According to Asser's *Vita Ælfredi*, King Alfred, for example, was initially unlikely to be a king, and trained for priesthood, but as his oldest brothers were killed, he begins accompanying his older brothers into battle and learning to be a military leader.
Alfred's own son, Edward, campaigned extensively alongside his father in the 880s and 890s, and according to William of Malmesbury, his grandson and future King of England, Æthelstan, was raised in the Mercian court of his aunt Æthelflæd, and accompanied her military campaigns against both the Welsh and the Vikings. During Æthelstan's reign, his brothers and heirs Edmund and Eadred both take part in the Battle of *Brunanburh* alongside the king, and the *Anglo-Saxon Chronicle* describes them leading the charge into the Viking lines.
Where this tradition is not in effect, it can cause issues. The reign of Æthelred II "the Unready" is beset by issues, many of which stem from the fact that he takes the throne as a child and only comes of age to rule independently in the 980s, a decade after his accession. Lavelle (2002) and Roach (2016) both suggest that many of the political problems in Æthelred's reign begin after the deaths of his late father's ministers, who had been largely administering the kingdom. These men were widely respected as experienced leaders, and had fought and campaigned together, and the young Æthelred lacked the experience, symbolism or practiced charisma of leading men into battle. | [
"From the feudal obligation of chief princes to stand by the king's side in word and deed, a consequent duty was derived by the time of the High Middle Ages to appear in person, at the request of the king, at royal assemblies in order to offer counsel and participate in decision-making. This was the so-called court... |
why can they lose 10lbs+ a week on the biggest loser when weight loss resources for us normals say not to lose more than 2lbs a week? | What's more discouraging is the more common scenario, where you think you're going to lose 10 pounds a week and then gain 1 because you don't realize how hard dieting is.
The Biggest Loser, like all TV, is about entertainment. A realistic diet program would have half the people losing no weight and maybe the best 1% losing 2 pounds a week; that would be incredibly uninteresting to watch. | [
"According to LiveScience.com, \"physicians and nutritionists worry the show's focus on competitive weight loss is, at best, counterproductive and, at worst, dangerous\". Contestants on the show lose upwards of 10 pounds per week (in the very first week, some contestants have lost 20–30+ pounds in that one week alo... |
how do some cities (e.g.) baltimore, washington, d.c., st. louis, etc. have neighborhoods that are very well developed and safe, but then, just a mere 5 or 10 miles away, there be a very impoverished and dangerous neighborhood? | 1. Wealth distribution and property values make a self-feeding cycle. More money in one neighborhood means better upkeep of buildings and infrastructure. This increases property value, which in turn encourages developers to invest more money into high-end developments.
2. Cities (and states and countries) have a different attitude and approach to wealthy and poor areas. This is why government housing (projects) and industrial zones still exist and are built in poor areas, while nicer areas become zoned for parks, schools, and high-end businesses and residences.
3. Natural economics means the liquor stores and pawn shops continue popping up in bad areas, while designer clothing stores and fancy cupcake bakeries open in good areas. | [
"The city is known for a great diversity of neighborhoods and land uses very close to one another. Within its borders are the prominent Hackensack University Medical Center, a trendy high-rise district about a mile long, classic suburban neighborhoods of single-family houses, stately older homes on acre-plus lots, ... |
What was the first song with the I-V-vi-IV chord progression? | [Andalusian Cadence!](_URL_2_) Also known as the Diatonic Phrygian Tetrachord--sometimes written as i-bVII-bVI-V (or, in the key of A, the descending sequence A, G, F, E)
[the Dorian tetrachord--](_URL_1_) A popular melodic pattern of Ancient Greece[5] offers a possible starting point for the Andalusian cadence. A sequence more or less close to the Greek tetrachord structure might have been known to the[ Moors in Southern Spain](_URL_0_) and spread from there through Western Europe. The French troubadours were influenced by the Spanish music. | [
"The I–V–vi–IV progression is a common chord progression popular across several genres of music. It involves the I, V, vi, and IV chords; for example, in the key of C major, this would be: C–G–Am–F. Uses based on a different starting point but with the same order of chords, include:\n",
"In music, the vi–ii–V–I p... |
If the Moon was created by an asteroid hitting the Earth, why didn't Earth get knocked out of its orbit around the Sun? | Because the earth is a whole lot heavier than the moon. Even an asteroid large enough to crash and knock out a moon-sized piece of the Earth would barely change the orbital speed of the Earth. Think of it like standing on the highway and throwing a rock as hard as you can at an oncoming semi-truck. Then you wonder why the truck didn't slow down. Sure, you probably made a dent in the metal wherever you hit it, and it slowed down *a little*, but not nearly enough to send it hurdling into the sun (ok, the analogy falls apart there). Also, because of the mathematics of orbital mechanics, orbits can change considerably and still remain stable, so even if something so large were to hit us that our momentum changed by a considerable amount, the Earth wouldn't get "knocked out" of its orbit | [
"The carbonaceous boulder that would have been captured by the mission (maximum 6 meter diameter, 20 tons) is too small to harm the Earth because it would burn up in the atmosphere. Redirecting the asteroid mass to a distant retrograde orbit around the Moon would ensure it could not hit Earth and also leave it in a... |
why do most foods taste terrible while going through chemo, but others have no change at all? | "Everything changed for me"
"I'll never forget the day that everything tadted like tofu. Everything tasted like nothing."
Source, wife who went through chemo last year.
Tastebuds are fast turnover cells that regenerate and die quickly. Chemo kills the tastebuds before they can develop and mature. What taste you lose is specific to you individually.
Source, same wife who is also a doctor. | [
"This may be done for medically necessary reasons, such as to change the form of the medication from a solid pill to a liquid, to avoid a non-essential ingredient that the patient is allergic to, or to obtain the exact dose(s) needed or deemed best of particular active pharmaceutical ingredient(s). It may also be d... |
Happy New Year, AskHistorians! You may now have historical relations with 1998. | To be fair, you have to have a very high IQ to understand Askhistorians comments. The historical analysis is extremely subtle, and without a solid grasp of Critical Theory most of the posts will go over a typical reader's head. There's also the mod team's nihilistic outlook, which is deftly woven into their content curation - their personal philosophy draws heavily from Pyrrhonic literature, for instance. The flairs understand this stuff; they have the intellectual capacity to truly appreciate the depths of these stickied comments, to realize that they're not just warnings against shitposting- they say something deep about LIFE. As a consequence people who dislike the Askhistorians mod team truly ARE idiots- of course they wouldn't appreciate, for instance, the humour in Automod's existencial catchphrase "[deleted]", which itself is a cryptic reference to Abelard's epic *Logica nostrorum petitioni sociorum*. I'm smirking right now just imagining one of those addlepated simpletons scratching their heads in confusion as /u/sunagainstgold's genius unfolds itself on their computer screens. What fools... how I pity them. And yes by the way, I DO have a complete Subreddit Rules tattoo. And no, you cannot see it. It's for the ladies' eyes only- And even they have to demonstrate that they're within 5 karma points of my own (preferably lower) beforehand. | [
"Happy New Year, America is an American television special that aired on the CBS television network to celebrate the New Year. It first aired on December 31, 1979 (leading into 1980), and last aired December 31, 1995 (leading into 1996).\n",
"Ron Grossman, writing for the \"Chicago Tribune\", opined that the spir... |
do animals see different stars than those we see? | There are two reasons why they see the same stars.
1. Pretty much every star gives off light in the visible spectrum.
2. Pretty much every animal can see the visible spectrum.
So effectively, we all see the same stars. The only reason some animals might see more or less is their sensitivity to a star's brightness. Some stars that are just barely fainter than our sensitivity to light will be visible to more sensitive animals and vice versa. Stars might also look a little different if animals are colorblind to certain regions of the spectrum relative to others, but they will continue to be visible. | [
"Research shows that animals sensitive to more than three color channels are likely to see the world in a very different way from humans. These animals are likely to experience different and more numerous unique hues, along with additional ways of mixing them.\n",
"Other animals, such as tropical fish and birds, ... |
Why did Londoners reject Empress Matilda in 1141? | We don't exactly know, unfortunately.
There were legitimate reasons for English people not to accept her as queen. When William I died in 1087, William Rufus immediately went to London to be crowned at the Tower; when William Rufus died in 1100, Henry I immediately went to London to be crowned at the Tower. When Henry I died in 1135, Matilda ... stayed in France, where, despite her role of heir presumptive to the English throne and former Holy Roman Empress, she was the countess of Anjou. She was pregnant at the time, and since her previous pregnancy had been quite dangerous, it's likely that she didn't want to risk the travel. That's fair, but as her cousin Stephen of Blois *did* cross the Channel and had himself crowned in London just a few weeks after Henry's death without any real reaction from her, it seemed quite natural for people to consider him the rightful king. He persuaded the Archbishop of Canterbury that Henry had forced his unwilling barons to swear the oaths acknowledging her as heir, and that he'd repented of it on his deathbed, so the Archbishop performed the coronation and Stephen effectively had God's mandate to rule. There was no opposition at the time.
Matilda's husband had begun fighting for Normandy (which was an English possession at the time; remember, it was William I's home turf) soon after this, but Matilda didn't get involved in presenting herself as the rightful ruler of England until 1139. She appealed to the pope and Stephen counter-appealed and won. Turning to military means, she enlisted the help of her brother, Robert of Gloucester, and made his county her base. She would basically take over southwestern England - which is not the part with London in it. Once she captured Stephen in early 1141, however, she was broadly allowed to have become queen, with the backing of religious authorities that had previously supported her cousin, and that's when she decided to get herself crowned in London to get the divine stamp of approval. She moved to take the city with soldiers, but was met by Stephen's forces, under his wife's command; when she succeeded, she was at first welcomed, but then, as you know, the Londoners turned on her and she was forced to escape.
*The Lioness Roared: The Problems of Female Rule in English History* lists the reasons given by primary sources, chronicles of the period: Henry of Huntington said that God caused the city to rise up; the Worcester chronicler wrote that the citizens asked her to let them live under "the excellent laws of King Edward" rather than her father's "oppressive ones" and she refused; the author of the *Gesta Stephani*, overall not a fan of hers, demanded a tax they didn't want to pay. The author, Charles Breem, interprets these criticisms as discomfort with a queen taking on masculine hardline authority, instead of acting with forgiving gentleness and compromise. This was not just a simple "women shouldn't do men things" - Stephen's wife directed his soldiers in protecting and retaking London, and the chroniclers were clear that this was brave and virtuous of her - but in large part there were people using "this is not appropriately-gendered behavior" as a justification for issues they already had. In this case, whatever the specifics, the Londoners didn't really want Matilda in the first place, and they probably wouldn't have been happy if she *had* released Stephen or taken a very publicly gentle stance. | [
"Empress Matilda (c. 7 February 110210 September 1167), also known as the Empress Maude, was one of the claimants to the English throne during the civil war known as the Anarchy. The daughter of King Henry I of England, she moved to Germany as a child when she married the future Holy Roman Emperor Henry V. She trav... |
time crystals, can this idea be simplified? | > Time crystals, can this idea be simplified?
Think about a salt crystal, it has a regular cubic structure which repeats in each of the three spatial dimensions. You can imagine a 3D lattice with each axis having a repeating sequence of atoms bonded together.
Now imagine that time is a dimension just like the spatial ones. A crystal in the dimension of time would have a repeating structure over time; basically it would cycle between states in a regular fashion. A "time crystal" then is a form of matter which cannot exist in a static equilibrium and instead cycles between states over time. | [
"The idea of a time crystal was first described by Nobel laureate Frank Wilczek in 2012. Later work developed a more precise definition for time crystals. It was proven that they cannot exist in equilibrium. Then, in 2014 Krzysztof Sacha predicted the behaviour of discrete time crystals in a periodically-driven man... |
why do i shake when i'm really hungry | Sounds like low blood sugar. You may have a prediabetic condition. It would be good to see a doctor. | [
"BULLET::::- Louder rumbles may occur when one is hungry. Around two hours after the stomach has been emptied, it sends signals to the brain, which tells the digestive muscles to restart peristalsis in a wave called the migrating motor complex. Food left behind after the first cycle is swept up, and the vibrations ... |
During World War II on the Pacific Front, how did American fighter planes get on equal footing with superior Japanese A6M2 Zeros? | [By developing this.](_URL_0_)
Also by [capturing one of them,](_URL_2_).
What was known was that the thing could turn like a beast and climb like a Valkyrie. It was very maneuverable and fast. Nothing the US had could come close to it. However once the US captured one they found that it could turn great but when forced to roll it performed horrible. Also if you dove and made them chase you the engine of the Zero would stall out. With this knowledge strategies where adopted. Once the F6F came into the picture it was game over.
Also of note was that like with almost EVERYTHING in military terms the best pilots/soldier wins. The Japanese had pilots that where REALLY good and experienced that flew the Zero's. Once they started losing them they where not able to refill their ranks fast enough and keep the staffed long enough before the US killed them. This led to a feedback loop of great planes being staffed by worse and worse pilots while the US got better and better pilots.
Edit: Also to Add to Backgrinders comment [Joe Foss](_URL_1_) a Marine Pilot ripped 4 Zero's apart in one pass to show you how vulnerable they where. Also I may be incorrect but Zeros did not have resealing gas tanks so one bullet = bad news. | [
"At the start of the war, the United States and Japan were well matched in aircraft carriers, in terms of numbers and quality. Both sides had nine, but the Mitsubishi A6M Zero carrier fighter plane was superior in terms of range and maneuverability to its American counterpart, the F4F Wildcat. By reverse engineerin... |
entropy, enthalpy, and hess's law | **Entropy** is the amount of energy in a system that is not available to do work - that is, it is "waste heat" that isn't useful. We know from thermodynamics that entropy is a measure of how likely a particular process will happen. Because a process that produces more randomness in the system is statistically favored, we say it has higher entropy. And while it is possible to increase the amount of order in the system (think of water freezing), we can only do this by using another process that produces even more entropy than you lose. This is the Second Law of Thermodynamics: the amount of entropy in the universe will always increase (ΔS_universe > 0).
For your class, just imagine that each substance in your chemical equation has a temperature-dependent amount of "randomness", which we track as the variable "S". A change in entropy is written as "ΔS". Entropy is a "state variable" - practically, this means that the value of S doesn't depend on how the substance arrived in that state (the path didn't matter, just the destination).
Entropy is measured in units of energy/temperature (i.e. Joules/Kelvin).
***
**Enthalpy** is a measure of the total energy of a system. For your class, you can just visualize it as the amount of "useful work" a system can do. We track it as the variable "H", which we can't directly measure. Because of this, we are ever only interested in "ΔH", the change in the energy of the substance. Enthalpy has units of energy, usually expressed per mole of material (Joules/mol). Like entropy, it's also a state variable, which will be important when we get to Hess' Law.
Every chemical equation has a "ΔH_rxn", which is the amount of heat absorbed or released by the reaction. If the system has less energy than before, ΔH is negative, and heat has gone from the system to the surroundings ("exothermic"). If it has more energy, ΔH is positive, and heat has gone from the surroundings into the system ("endothermic"). We can measure ΔH directly by using a calorimeter (you've probably used one in your class experiments).
Every substance has a "ΔH_formation", which is the ΔH of the reaction used to form it from its elemental parts. For example, ΔH_f of methane (CH4) comes from the reaction C + 4H -- > CH4 (notice we're using elemental hydrogen, not hydrogen gas). You can think of ΔH_f as "the amount of energy in this particular compound".
***
**Hess' Law** is what makes that last paragraph useful. Remember how I said enthalpy is a state variable? That means that it doesn't matter what reaction path we take to form a particular compound - ΔH will be the same no matter what. This allows us to use ΔH_f's to compute the ΔH of any reaction we want!
Imagine the combustion of methane: CH4 + 2 O2 -- > CO2 + 2 H2. We want to know how much energy is released or absorbed (ΔH_rxn). We could use a bomb calorimeter to measure it directly, but your school was forced to sell all its lab equipment due to budget cuts. But it's okay! Visualize all the atoms of the reactants breaking apart into all their separate C's, H's, and O's. Because this is the opposite of a formation reaction, we can write ΔH = -[sum of ΔH_f_reactants]. Now imagine all those letters recombining to form the compounds on the other side of the equation; this is a formation reaction with ΔH = [sum of ΔH_f_products].
Now for the big finish - since enthalpy is a state variable, it didn't matter that we took two steps instead of one! So just add the enthalpy changes of the two steps together:
> ΔH_rxn = [sum of ΔH_f_products] - [sum of ΔH_f_reactants]
So using Hess' Law is really just playing accountant. First, use the table in the back of your textbook to find ΔH_f for each of the compounds in your reaction. Then, sum together all the heats from the products and subtract those of the reactants. Don't forget to multiply each term by its stoichiometric coefficient (two moles have twice as much heat as one).
Hope all that helps! | [
"The enthalpy of solution is the solution enthalpy minus the enthalpy of the separate systems, whereas the entropy is the corresponding difference in entropy. Most gases have a negative enthalpy of solution. A negative enthalpy of solution means that the solute is less soluble at high temperatures. The sum of the e... |
If the Hubble Telescope was in orbit around Alpha Centauri, pointing at our solar system, how many of the planets and other orbiting bodies could it see? | If we were lined up just right then they could probably see a transit of Venus and Earth. Essentially a mini-eclipse as the planets crossed the disk of the sun. The problem with Jupiter and Saturn is their years are so long they would take a long time to be confirmed. Jupiter takes 12 years to go around the sun, so you'd need to be observing for at least 36 years to confirm a transit. (2 times to determine a year length and a third to confirm it was a planet and not a large sunspot)
As for seeing the planets directly, nope. The glare from the sun is way too much. If you look at the list of exoplanets which have been directly observed, they are very far out (most are more than Pluto distances away) and much larger than Jupiter. Also the planets are relatively young, so they are hotter and are seen because of the energy emitted by the planet, not reflected from the star.
_URL_0_ | [
"More recent (and accurate) astrometric observations by the Hubble Space Telescope ruled out the existence of such an object entirely. The 1995 study predicted an astrometric movement of roughly 90 mas (0.09 arcseconds), but Hubble was unable to detect any location anomaly to an accuracy of 5 mas (0.005 arcsec). Th... |
why does medicine get into your system faster than food? | Most pills are basically small molecules designed to disolve and go right in. Most food is large molecules that need to be broken down first. | [
"Some drugs, such as the prokinetic agents increase the speed with which a substance passes through the intestines. If a drug is present in the digestive tract's absorption zone for less time its blood concentration will decrease. The opposite will occur with drugs that decrease intestinal motility.\n",
"The amou... |
what are the actual benefits to eating ones placenta? | Despite the belief of the many health benefits of eating your placenta, there is no conclusive evidence that placentophagy provides any substantial nutritional value. In fact the preparation process (cooking the placenta or drying it for encapsulation) removes a large portion of its nutrients by reducing protein hormones and other things.
Some suggest that the health benefits perceived by people who consume their placenta is caused by the placebo effect.
Eating your placenta will provide you with about enough caloric energy and nutrition to make it to your next meal in the day (which is the most likely reason wildlife can be observed performing this practice as well). | [
"Those who advocate placentophagy in humans believe that eating the placenta prevents postpartum depression and other pregnancy complications. Obstetrician and spokesperson for the Royal College of Obstetricians and Gynaecologists Maggie Blott disputes the post-natal depression theory, stating there is no medical r... |
Were there any women that left an impact during Renaissance Italy? | Oh, yes! I have [an earlier answer](_URL_0_) on "Renaissance women" bouncing off the idea of Leonardo da Vinci as a "Renaissance man" that might interest you. :D
But that post was narrow in scope to intellectual/polymath types. There were so many more ways that individual women made an impact! Religious leaders claiming gifts of ecstatic prophecy like bitter archrival nuns Domenica dal Paradiso and Dorotea da Lanciuole played active, even leading roles in post-Savonarolan religious politics--their feud spanned a decade and involved the entire city's mendicant community. Catherine of Genoa was a mystic who, more quietly, dictated her teachings to a circle of students.
Women also involved themselves in the flourishing art scene. Catherine of Bologna is probably the most famous one today. Antonia Pulchi was a playwright, composer, and lyricist of religious dramas and music that were performed in her native city of Florence.
And then, of course, there were the aristocrats and politicians. Even though women were barred from holding formal office and in Italy, specifically, were almost never heads of household, as mediators and as proxies for male relatives they wielded a surprising amount of indirect influence and direct power. Alfonsina Orsini ruled Florence from 1517-1519 during yet another period of *male* Medici exile from the city.
There are two important points to raise here. First, nearly all the standout women from Renaissance Italy we can point to were not married: they were nuns, tertiaries (informal nuns), or widows. With the intellectual/humanist women in particular, the sad pattern is a father providing his daughter the best education possible, she flourishes as a young woman author/philosopher/theologian--and as soon as she marries, ceases public literary activity.
Second, when we talk about "Renaissance" Italy, we are necessarily speaking primarily or exclusively of the upper crust. There are some women among the tertiaries who would have had a more middle class background. But in general, "the Renaissance" and its developments were an urban and elite phenomenon. We don't hear about peasant widows making great art or writing religious plays for their village confraternity.
Nevertheless, there are some really excellent stories based around phenomenal--for good or ill--women to come out of 15th-16th century Italy. And thanks to the literary grounding of its elite society, we can tell those stories in quite a bit of depth today. | [
"The Renaissance (15th–16th centuries) challenged conventional customs from the Medieval period. Women were still confined to the roles of \"monaca, moglie, serva, cortigiana\" (\"nun, wife, servant, courtesan\"). However, literacy spread among upper-class women in Italy and a growing number of them stepped out int... |
Why did Saudi Arabia back Communist South Yemen against the US backed Republic of Yemen in the 1994 Yemeni Civil War? | The Saudis had long backed and had long-standing connections with traditionalist forces in North Yemen. In the 1962-70 North Yemen Civil War (really a proxy war) they backed the Zaydi Shia Mutawakkilite Kingdom of Yemen against the Egyptian-backed Yemen Arab Republic. The death of Nasser in 1970 helped bring an end to the hottest phase of the Arab Cold War and Saudi Arabia recognized the victorious Yemen Arab Republic and worked in coordination with various factions in North Yemen, preferring it over the Marxist South.
Yemen's unification in 1990 came at a precarious time. The overall Cold War was ending with a Soviet collapse and Saddam Hussein's invasion of Kuwait threatened to rip apart the Middle East. The president of the newly re-united Yemen, Ali Abdullah Saleh, backed Saddam in sharp contrast to the rest of the Gulf States.
Partly as a result of that the GCC countries split from Saleh, and flirted with the secessionist movement in 1994. As it happened, the 1994 Civil War so brief that I'm not sure you should quite read into it the way the wording of your question suggests.
[Saleh claimed US support](_URL_2_) but it wasn't a major break from the rest of the US' GCC partners.
Saleh won so quickly that the war couldn't become the kind of protracted proxy conflict that characterized the North Yemen Civil war decades prior, or for that matter that characterizes the conflict in Syria today.
The other motivating issue that remains relevant are accusations that Saudi Arabia is concerned about the potential power of a united Yemen on its southern border. The population of Yemen is at least equal to Saudi Arabia, and that's only if you believe the official Saudi population figures, which are dubious and likely inflated.
You're not likely to find much in the way of concrete discussion/documentation of any of these factors from Saudi officials, however. Saudi Arabia remains one of the most opaque polities in the world, these Carnegie Endowment articles would be a good overview though:
_URL_0_
_URL_1_
| [
"Southern leaders, supported by the Saudis, declared secession and the establishment of the Democratic Republic of Yemen (DRY) on May 21, 1994, but the Democratic Republic of Yemen was not recognized by the international community. Although the southerners had their own motives for fighting, northern leaders have l... |
how are asynchronous calls used? | Synchronous call - I'll drop you off at the store and wait her until you come back
Asynchronous call - I'll drop you off at the store and periodically check to see if you are done
Most calls are synchronous because the caller usually wants something right now and can't really proceed without it.
But if what the call is doing is low priority, can take a long time, or is outside the control of the system, asynchronous calls make more sense. The drawback is they require extra logic to periodically check to see if the call has completed, or if it fails to complete. | [
"In Windows, an asynchronous procedure call (abbreviated APC) is a function that executes asynchronously in the context of a specific thread. APCs can be generated by the system (kernel-mode APCs) or by an application (user mode APCs).\n",
"In multithreaded computer programming, asynchronous method invocation (AM... |
how when using a proxy such as tunnelbear, google maps can still pinpoint my correct location. | can't be sure of the exact method, but at the very least you can be sure that Google Maps was not relying on the IP address of your http request to determine your location. | [
"Location inference is the method of identifying the location profiles of users on social media platforms such as Twitter and Facebook from their message content, friends' network and social interaction even when they did not explicitly disclose such on their account profiles or geotag their messages.\n",
"Probab... |
Is there a physical reason for why some mental tasks require more effort? | The best why I can describe this is how a computer works. A computer processes data and displays that data on a screen. A single core computer is of like the windows 95 or 97 version. The more cores you have the better the computer processes data. This is kinda like what IQ means. IQ isn't how smart you are, it's how well you can process information. The Questions in an IQ test are to specifically to see what you can process and if you can come up with the right answer in a fast enough time. So basically some tasks require a deeper thinking. Those with high IQs can process high amounts of information or the core of a problem at a better rate than someone with a low IQ. Think of someone with mental disabilities. It takes them a while to do a simple task that would be a normal task for someone without those disabilities. | [
"A desirable difficulty is a learning task that requires a considerable but desirable amount of effort, thereby improving long-term performance. The term was first coined by Robert A. Bjork in 1994. As the name suggests, desirable difficulties should be both desirable and difficult. Research suggests that while dif... |
- how does high octane fuel actually benefit a car in the real world? | Higher octane fuel is more stable at high temperatures and pressures than lower octane fuel. In an engine, there is a thing called 'Knocking' that can happen if you squeeze/heat fuel too much, and it's basically the fuel spontaneously combusting instead of being ignited by the spark plug.
Why is that a problem? Well in a diesel engine it isn't, because they are designed for it. A gasoline engine, however, is not built for it (literally: less metal, thinner walls, etc). When the fuel spontaneously combusts, two bad things can/do happen.
1. The explosion happens too soon, the piston is in the wrong position.
2. The explosion starts in the wrong spot, and so it puts stress on parts of the cylinder from directions they were not built to handle.
This can cause tremendous damage to an engine. Higher octane fuel prevents this premature detonation.
edit: The engineers know what your engine will do under normal operation. IF your engine says it needs 87 octane, you do NOT need higher octane fuel to prevent knocking unless you install a turbo or some other compression/temperature modification to the car. | [
"The octane rating of a given fuel is a measure of the fuel's resistance to self-ignition. A fuel with a higher numerical octane rating allows for a higher compression ratio, which extracts more energy from the fuel and more effectively converts that energy into useful work while at the same time preventing engine ... |
What's causing the strange ice behavior in this video? | Hi there, since this is a crosspost linked to a very popular video on Reddit at the moment, I figured I should welcome some redditors unfamiliar with AskScience.
Welcome to AskScience! We have a few specific rules on this subreddit, you can find them on the sidebar that way --- >
In a nutshell, please do not respond with personal anecdotes or speculations. Please stay on topic, even though you might have a funny tangent to get that sweet sweet karma (you can post that [joke here instead](_URL_0_)!).
Thanks
AskScience Mod Team | [
"An ice hummock is a boss or rounded knoll of ice rising above the general level of an ice-field. Hummocky ice is caused by slow and unequal pressure in the main body of the packed ice, and by unequal structure and temperature at a later period.\n",
"The video for \"Ice\" consists mostly of two scenes. The first ... |
let's say i have 10.000 dollars and wanna get into the stock market. what do i do? | Go to a quality site like _URL_0_, create a portfolio (used to be free, now it might require basic membership of around $7 a month, not sure), and set the parameters (such as how much the assumed cost is per transaction fee, account value, etc...)
Now, this imaginary portfolio will be tracked and charted as though it was real. Spend a few months learning about the stock market, and buying and selling the money in this portfolio as you think you should.
As you learn and develop new strategies, create new portfolios and test them in a the same fashion. After a few months, you can see EXACTLY how successful the different strategies were... review what worked and what didn't.
THEN, and only then, open a real account and put it on the line. I would recommend Scottrade.
If you figure out a formula that works, the HARDEST THING IN THE WORLD is to stick to it. Don't get greedy... it is easier than you think. Stick to your plan, or stop, scrap the plan in its entirety and re-evaluate before continuing.
SOURCE: Used to daytrade a LOT... as in, highest volume year had a 40 page transaction report on my tax return with almost $4 million in trades. | [
"\"My job is constant— like the stock market, I have to know value of how much people pay— Sweden, France. I know what he can make in MLS, China, Germany. I know that and I am up-to-date with the market. You have to know the world markets in terms of how much people earn and the values of certain players.\n",
"Th... |
Tidal effect of the Moon on Earth in perspective.. | There are a couple of diagrams [here](_URL_0_) that illustrate the direction and *relative* magnitude of tidal acceleration over the surface of the earth.
Note that I would not describe this exactly as "the moon's gravity tugging on the Earth's surface water." This can at least potentially be misleading; for example, consider the example presented in the link above: what would be the effect on the tides of a *second* moon, on the opposite side of the earth (at the same distance)? Would the gravitational "tugging" of the two moons "cancel" the tides, or increase them? (Answer: the latter.)
| [
"In a like manner, the lunar surface experiences tides of around amplitude over 27 days, with two components: a fixed one due to Earth, because they are in synchronous rotation, and a varying component from the Sun. The Earth-induced component arises from libration, a result of the Moon's orbital eccentricity (if t... |
can someone [eli5] all or at least most of ron paul's ideas? | In a nutshell, "Mind your own damned business." | [
"David Weigel of \"Reason\" reviewed the book favorably, comparing Paul's political ideas to those of fellow anti-war conservative Sen. Chuck Hagel. \"Paul has a grand unified theory to offer readers, knowing full well that he's opening minds, not programming them,\" Weigel wrote, adding that Paul \"offers readers,... |
when a body of water reaches boiling temperature, why does it not all become steam at once? | _URL_0_
> Latent heat of vaporization.
It's generally accepted that water always boils when it reaches exactly 100 Celsius. This is not entirely the case, but we'll assume that it's true for the explanation since it illustrates the point.
Once water hits 100 degrees, all heat added to the system no longer raises its temperature; instead the extra energy allows water molecules to break free from the surface tension and escape into the atmosphere, even if the atmosphere is already saturated with water. This is what we characterize as the state change from liquid to gas.
This extra energy is not added symmetrically to the collection of liquid; rather, it's transferred as radiant or conducted heat from one or multiple directions. The thin layer of water closest to the heat source absorbs the energy and creates a localized state change into a gas, which can then be reabsorbed by the water and the energy distributed, or can rise as a bubble with more gaseous water and escape the liquid. The more energy you add at the boiling point, the more water that turns to a gas, and the more violent the boil. Convection then replenishes the water against the heat source, which absorbs sufficient heat to vaporize and the cycle continues.
If you have a sufficiently hot source and a sufficiently small amount of water, you can flash boil an entire collection of water, like if you throw a cup of water on a lava flow or hot fire - nearly all of the water vaporizes at once. However, this requires a great amount of surface area for the water to contact the heat source, and a very large heat differential between the two.
courtesy of /u/techadams | [
"Water and other homogeneous liquids can superheat when heated in a microwave oven in a container with a smooth surface. That is, the liquid reaches a temperature slightly above its normal boiling point without bubbles of vapour forming inside the liquid. The boiling process can start explosively when the liquid is... |
How exactly does cartilage "join/stick" to bone? | Cartilage transition happens in 4 zones, with details [here](_URL_1_).
All parts of the cartilage is important for load distribution, but where a transition from cartilagenous histology to more bone-like histology appears at the *tidemark* zone. A really good picture of this can be found [here](_URL_0_) showing the transition from more pliant non-calcified cartilage to the hardened calcified cartilage. | [
"Osteons are components or principal structures of compact bone. During the formation of bone spicules, cytoplasmic processes from osteoblasts interconnect. This becomes the canaliculi of osteons. Since bone spicules tend to form around blood vessels, the perivascular space is greatly reduced as the bone continues ... |
when you drink a glass of water, how does it get around your body to become saliva or tears? | The water you drink travels through your digestive system to get absorbed by cells lining your small intestines and large intestines. These cells pass the water on into your bloodstream, and hence water circulates as blood around your body.
Blood vessels supply the cells in your body with water, oxygen, and other nutrients via diffusion and through other channels. These nutrients are essential for every cell in your body to perform their function
Similarly, cells in your lacrimal glands (which produce tears) and salivary glands (comprising submandibular, submental, and parotid glands) will use these nutrients as well, and they function to combine water with other substances to form tears and saliva respectively. | [
"The sodium ions in the ECF also play an important role in the movement of water from one body compartment to the other. When tears are secreted, or saliva is formed, sodium ions are pumped from the ECF into the ducts in which these fluids are formed and collected. The water content of these solutions results from ... |
why are human penises so long compared to most other primate penises? | There's a very interesting theory about this, called the sperm (or semen) displacement theory. It goes a little something like this.
Way back when, humans, and in particular, human males, weren't so much into the pair-bonding thing, and women regularly had sex with multiple men. This meant that the sperm in the woman's vagina (which can live for a few days) wasn't necessarily 100% yours. Larger penises with coronal ridges (that is, a long shaft with a slightly wider head) created a "vacuum scraper" that essentially allowed the most recent male mate to scrape away the semen from the previous mate. Larger penises achieved this more effectively than smaller penises, giving them the selective advantage necessary to become a relatively common trait among human males. | [
"The human penis is thicker than that of any other primate, both in absolute terms and relative to the rest of the body. Early research, based on inaccurate measurements, concluded that the human penis was also longer. In fact, the penis of the common chimpanzee is no shorter than in humans, averaging 14.4 cm (5.7 ... |
if i drive at a constant speed up and over a hill, coasting down the other side, will the extra fuel i consume on the way up be equal to the fuel i'll save on the way back down? | No. You'll burn extra fuel getting up the hill, but you won't save that much going down the other side, because your engine will be (at least) idling, which consumes some fuel. | [
"Fuel economy-maximizing behaviors also help reduce fuel consumption. Among the most effective are moderate (as opposed to aggressive) driving, driving at lower speeds, using cruise control, and turning off a vehicle's engine at stops rather than idling. A vehicle's gas mileage decreases rapidly with increasing hig... |
us school system from 0 to phd. (details in post) | 0-4ish: pre-school, this is optional but is correlated with higher socioeconomic status and attending is shown to be a good predictor of future success.
5-11: kingergarten (grade 0) and grades 1-6, this is called elementary or primary school.
12-13: middle school, or junior high school. grades 7-8
14-17: high school or senior high school, grades 9-12, with years referred to as freshman, sophomore, junior, and senior. These schools are separated differently depending on the school districts. My schooling has grades 0-6 in one school and 7-12 in another school. This is compulsory until the age of 16.
18+ is university, which typically starts with about 4 years of an undergraduate program, and usually culminates with a bachelor of science or a bachelor of arts, but there are also other programs, such as 5 year engineering programs which end with a masters, or other vocational programs like nursing, etc. Some people decided to go to community college first, which are typically local to each county, and have 2-year programs that reward an associates degree, which can later be applied to the first two years of a 4-year program at a university. Community colleges also have vocational programs like the trades (carpentry, electrician, mechanic), and may have other programs like nursing.
After you have a 4-year degree, you can choose to pursue higher (postgraduate) education. Most masters and doctorate programs are examples of postgraduate education.
In the sciences, most candidates pursuing PhDs are fully funded by their university, and some receive a Masters degree along the way. PhD programs typically take about six years and must include original research.
In engineering or the liberal arts, you can go for a masters or PhD but these programs are less likely to be funded. A masters usually takes 2-3 years.
There are also the professions, such as medicine, dentistry, and law, which have their own separate schools and processes, but are still likely to be part of the major universities. These programs are all very expensive, and can be extremely competitive to get into. A typical MD will graduate with $250,000 in debt. | [
"All schools offer undergraduate degrees at the level of Licenciatura (5 years) and graduate degrees at the level of master's degree (2 years) and PhD (3–4 years) from the Graduate School. The Graduate School, founded in 1941, offers 222 different specializations, 109 Master's degrees and 40 PhDs.\n",
"The United... |
differences between summer seasons on the north and south hemispheres | you seem to be confused - the days do not get longer at just one end of the day. both sunrise and sunset get earlier and later at roughly an equal rate. the closer you are to the poles, the more drastically they change, and the closer you are to the equator the less they change.
the graphs below help demonstrate this. go to the link, and slide your mouse along the big blue graph with the red line. underneath you will see the sunrise and sunset times growing and shrinking together. (those jumps near the beginning and end is when daylight savings comes in). i chose london and melbourne as the cities to use as examples, both relatively far north and south respectively.
_URL_1_
_URL_0_ | [
"Where a seasonal lag of half a season or more is common, reckoning based on astronomical markers is shifted half a season. By this method, in North America, summer is the period from the summer solstice (usually 20 or 21 June in the Northern Hemisphere) to the autumn equinox.\n",
"Summer is the hottest of the fo... |
Who/what have been the biggest and most interesting gangs in history? | It you'd classify them as a "gang" (I would) Blackbeard's pirates are interesting. | [
"A number of gangs have gained notoriety in the course of history, including the Italian Mafia, the Russian mafia, the Irish mob, the Polish mob, the Jewish mob, the Albanian mafia, the Yakuza in Japan, the Kkangpae in Korea, the Triads in China, the gangs of New England, the Jamaican Shower Posse and Yardies, the ... |
regarding numbers, if i have an infinite decimal such as .999999.... is it the same as 1 because it infinitely approaches 1? | I think the easiest way to explain it is: 1/9 = 0.111..., and 9 x 0.111... would be 0.999... for the same reason that 4 x 111 = 444. So we have 9 x 1/9 = 0.999..., and 9 x 1/9 = 9/9 = 1. So we have 1 = 0.999... | [
"Some proofs that 0.999... = 1 rely on the Archimedean property of the real numbers: that there are no nonzero infinitesimals. Specifically, the difference 1 − 0.999... must be smaller than any positive rational number, so it must be an infinitesimal; but since the reals do not contain nonzero infinitesimals, the d... |
what's with all the smoke or steam that comes out of the street in big cities, primarily new york? | It's steam and it's most likely blowoff from the steam heating system. Power plants generate excess steam and instead of dumping it into the air, they pipe it all over the city to heat buildings. | [
"Outside of the imposing free-standing stone building, a coin-operated \"steampunk\" engine greets visitors, complete with lights, engine and train while noises, and fire breathing out of its chimney. The building's exterior walls are decorated with creations such as giant flies made from metal and industrial parts... |
What influence did the Iroquois Confederacy, Pre-Kings Israel, and other non-Hellenstic precedent have on the forming of the U.S. Constitution? | I'm probably going to offend you in saying this, but this sounds a *lot* like a homework question. If so, we can provide you with good sources, but we can't answer it for you. | [
"In the 20th century, some writers have credited the Iroquois nations' political confederacy and democratic government as being influences for the development of the Articles of Confederation and the United States Constitution. In October 1988, the U.S. Congress passed Concurrent Resolution 331 to recognize the inf... |
why is happening psychologically in a murder suicide when the victims are not even people the killer knows? why would somebody who intends to take their own life want to kill others before doing so? | Typically such a person believes he has been treated unjustly by society, so he is striking back at society in general -- which includes basically everyone.
_URL_0_ | [
"A murder–suicide is an act in which an individual kills one or more people before (or while) killing oneself. The combination of murder and suicide can take various forms, often linked to the first form:\n",
"There are two broad categories of \"suicide by cop\". The first is when someone has committed a crime an... |
Chances of survival in a tsunami? | I'm not sure that swimming skills would help much. Someone looking at tsunami videos [estimated](_URL_0_) the velocity of the recent tsunami in Japan over land near the Sendai airport at 5-6 m/s. World-caliber swimmers go about 2 m/s during a race -- but that's in nearly-perfect conditions. In a tsunami, you'd be wearing clothes and swimming in extremely rough water.
So you wouldn't have much choice about where you'd be going, you'd be in rough (and possibly very cold) water with tons of debris and unpredictable currents, you'd be weighed down with wet clothing, and you might be submerged at unexpected times. If you hit something stationary, it'd be like you swam into it twice as fast as an Olympic swimmer goes. Imagine hitting a pool wall like that, and then getting pinned there (the water's still coming!) while debris comes your way at that same speed and the water level possibly continues to rise -- that probably wouldn't end well.
If you absolutely couldn't avoid the wave, I'd say you'd probably want to find something large and buoyant and hope for the best. You really wouldn't want to swim for it. | [
"The risk of a tsunami wave between 4 m and 7 m high is estimated as a possibility every 600 to 1500 years. The occurrence of an event comparable to that of 1603, could have grave social and economic consequences as areas near the sea are largely built up, in particular for tourist activity in the region of Sliema.... |
why do aerial pictures of cities show flat top buildings from different angles? | If you wanted a picture of every building from exactly overhead you would need to fly exactly over every one. That is a ton of flying, it is much easier just to fly where you can see them. | [
"Aerial picture pairs, when viewed through a stereo viewer, offer a pronounced stereo effect of landscape and buildings. High buildings appear to 'keel over' in the direction away from the centre of the photograph. Measurements of this parallax are used to deduce the height of the buildings, provided that flying he... |
why do "luxury" cars have bad gas mileage, while 15-20 thousand dollar cars have good gas milage? | People who can afford and purchase luxury cars aren't usually concerned by mpg. Also these cars often serve as a status symbol, so the bigger the engine, the more expensive and exotic the car is, you look "better" with that car. Whereas cheaper cars are aimed towards people who commute, and have to go from A to B while spending the least, so it's a great selling point to be able to travel more for less. | [
"Critics of the Gas Guzzler Tax contend that the increased fuel economy of the US passenger car fleet observed since 1978 must be considered in the context of the increased market share of mid-size and full-size SUVs. Many consumers' stated reasons for SUV purchase (comfort, interior room, and a perception of safet... |
how/why do we simultaneously have eye contact with another individual although we were not thinking about it. | random chance and recognizing false patters.
How many faces do your eyes shift to in a full room? 10? 20? A hundred? How often do you catch people's eyes just at the right time? Maybe once? It's not that it happens that often, its that when it does happen, its memorable. | [
"Eye contact occurs when two people look at each other's eyes at the same time. In human beings, eye contact is a form of nonverbal communication and is thought to have a large influence on social behavior. Coined in the early to mid-1960s, the term came from the West to often define the act as a meaningful and imp... |
if transistors in computers are so small and there are billions of them, then how are computers so cheap (relatively speaking)? shouldn't it take a lot of effort to put all of the transistors in the right places? | > Shouldn't it take a lot of effort to put all of the transistors in the right places?
Transistors aren't "put in place". All of the billions of transistors are created together at the same time, using a technique called [photolithography](_URL_0_). In simple terms, CPUs are manufactured in a manner similar to how you would develop a photograph from a piece of film.
Yes, it's expensive, but most of the expense is in the development of new processors, and the equipment needed to manufacture them. That cost is spread out across all of the millions and millions of processors that are sold. | [
"As it becomes more difficult to manufacture ever smaller transistors, companies are using Multi-chip modules, Three-dimensional integrated circuits, 3D NAND, Package on package, and Through-silicon vias to increase performance and reducing size, without having to reduce the size of the transistors. \n",
"The tra... |
why are brains wrinkly? | > that doesn't answer why a smooth brain wouldn't be able to hold the same amount of grey matter with a similar volume to a wrinkly brain.
Your head can only get so big before your neck can no longer support it. So in order for more neurons to fit in the skull, the increase in surface area must be in wrinkles rather than over a smooth area. | [
"A characteristic of the brain is the cortical folding known as gyrification. During fetal development, the cortex starts off smooth. By the gestational age of 24 weeks, the wrinkled morphology showing the fissures that begin to mark out the lobes of the brain is evident. Scientists do not have a clear answer as to... |
how do theft detectors in shops know you've bought the item? is it to do with scanning the barcode, or is there something else that gets scanned? | Most theft detectors rely on one of two mechanisms. Small tags and large tags.
Large tags get removed by the cashier, and are either attached in a way that damages the item if you try and force it open or locked in a larger and more cumbersome package.
Small tags are usually small magnetic stickers, and are demagnetized during the checkout process. You may see in some stores that there is a large circle on the counter that the clerk slides everything across. That's for small tags.
With the tags demagnetized, you can pass through the theft detectors without setting off alarms. | [
"When checking out at a grocery store, the cashier will scan the barcode of each item to determine the total cost. A thief could replace barcodes on his items with those of cheaper items. In this attack the cashier is a confused deputy that is using seemingly valid barcodes to determine the total cost.\n",
"Elect... |
entropy. | Here we have a cardboard box, about the size of a shoebox, filled with coins. Not a ton of them, just enough so that the all lay flat on the bottom of the box.
There are three possible states for that box to be in: all coins heads-side-up, all coins heads-side-down, and the other thing where some of the coins are heads-up and some are heads-down.
Imagine the box starts out in the all-coins-up state. We put the lid on and shake it. Without opening the lid, what state do you expect the box to be in?
The answer is obvious: Some of the coins will be heads-up and some will be heads-down. Why? Because the all-heads-up and all-heads-down states correspond to *exactly one arrangement of coins* each, while there are *many* arrangements of coins that correspond to the some-up-some-down state.
The "all-up, all-down, some-of-both" states are what we call *macrostates.* They're the states we care about, the ones we can easily observe. The individual position and heads-up-or-down-ness of all the coins comprises what we call a *microstate.* It's a state that is normally invisible to us, hidden from view, either because we just don't care about that much detail, or because that much detail is practically impossible for us to measure.
Entropy is, in a sense, how many microstates correspond to a particular macrostate. In this example, the all-heads-up and all-heads-down macrostates each correspond to just a single microstate; that's a very low-entropy condition. But the some-of-each macrostate corresponds to *many* microstates, making that a high-entropy condition.
When we started out, all the coins were heads-side-up, but when we put the lid on the box and shook it, the system moved from a low-entropy state to a high-entropy state.
In nature, systems always tend to move from low-entropy to high-entropy states. In the most abstract sense, this is just because of pure dumb luck: There are more combinations of coins that add up to "some of each" than either "all up" or "all down," so *pure random chance* dictates that we're far more likely to go from the all-up state to the some-of-each state than the other way around … and furthermore, that as we continue to shake the box, we're far more likely to *stay* in the some-of-each state, because the odds against getting all the coins to land heads-side-up are enormous.
In reality, this use of pure-dumb-luck-based statistics to describe complex systems is a mathematical approximation. After all, things like the motions of molecules in a bathtub of water aren't really random. They're actually the product of a *huge* number of very simple interactions … but that's the thing. When you take something that's fundamentally simple but that becomes vastly complex because of sheer scale, that thing tends to behave very much like a purely random system governed by dumb luck. So it turns out those dumb-luck-based statistical approximations are actually incredibly useful and predictive.
So basically, entropy can be thought of as a way of quantifying just how likely or unlikely it is that a complex system will evolve in a particular way. If the evolution you're imagining is from a low-entropy state to a high-entropy state, in general that's pretty likely. If it's the other way around, from a high-entropy state to a low-entropy state, then in general that's probably not going to happen. The more complex the system you're thinking about, the better statistical methods tend to be for predicting the evolution of that system over time. | [
"In information theory, \"entropy\" is the measure of the amount of information that is missing before reception and is sometimes referred to as \"Shannon entropy\". Shannon entropy is a broad and general concept which finds applications in information theory as well as thermodynamics. It was originally devised by ... |
why do some substances stain certain types of clothing while others don't? | It's an inverse relationship - the less you want your SO to know you ate it, the more it stains. | [
"A stain is a discoloration that can be clearly distinguished from the surface, material, or medium it is found upon. They are caused by the chemical or physical interaction of two dissimilar materials. Staining is used for biochemical research, metal staining, and art (e.g., wood staining, stained glass).\n",
"T... |
supply and demand, price elasticity of demand, marginal cost, and monopolies. | Supply and demand work hand in hand to regulate price in an economy. When a new iPhone comes out, the demand for it is high, so Apple can charge a high price for it.
But if Apple overestimates the number of iPhones it could have sold, it will flood the market with surplus iPhones (the supply of iPhones exceeds the demand for them) and they will have to drop the price to convince people to buy these iPhones.
Price elasticity of demand is a measure of how much the demand of a good changes in comparison to its price. Say Apple starts charging $1000 for new iPhones. The demand would drop drastically because no one wants to pay that kind of money for a cell phone. So the iPhone has an elastic demand.
But if your city starts charging you 3 or even 5 times for water, your demand will not change much (in fact you may start using exactly what you need and stop wasting water - this will be your true demand since you did not need that excess water). So water has a price inelastic demand.
Marginal cost is the cost of producing each additional good. Say Apple opens a new iPhone manufacturing plant. The cost of producing the first iPhone will be in millions of dollars (the land, building, machines, labor etc), but the next unit will be much cheaper (plastic, glass, processor, microphone, speaker etc). Over a period of time, Apple can produce iPhones for dirt cheap and this is when they start making profit. If that first iPhone sold for $500, Apple lost millions. But when they sell their 1 millionth iPhone, they made a huge profit.
A producer is called a monopoly when it and only it is capable of providing a certain good or service. If tomorrow Samsung/Motorola/Nokia all disappeared and Apple was the only manufacturer of smartphones, it would have a monopoly in that market segment. Governments everywhere try their hardest to prevent monopolies because these are generally not healthy for a free market at all. Microsoft had a near monopoly in the Operating System (and the internet browser segment) market for a long time. You can
easily google the anti-trust charges against them in several countries and the lawsuits they have fought and lost.
| [
"BULLET::::- \"Supply Curve\": in a perfectly competitive market there is a well defined supply function with a one-to-one relationship between price and quantity supplied. In a monopolistic market no such supply relationship exists. A monopolist cannot trace a short term supply curve because for a given price ther... |
why my two week disposable contacts need to be disposed of after two weeks? | A few different reasons, actually. One, the most prominent, is that your eyes will build up protein deposits on the contacts. The solution you clean them in helps with this, but any solution powerful enough to clean the lens completely is going to be powerful enough to physically break down the lens itself.
Also, soft lenses will begin to change shape over time to fit your eye, which means their ability to adjust your vision degrades. Hard contact lenses do not have this problem, they will actually slightly reshape your eye, but you lose a lot of the comfort and ease of soft lenses.
Contacts are a lot like motor oil in a car. Even if you don't use it, the material that makes it up will eventually just break down and deteriorate over time, but having them in your eye accelerates this process. | [
"A slight variant has multiple contacts designed to engage in rapid succession. The first to make contact and last to break will experience the greatest contact wear and will form a high-resistance connection that would cause excessive heating inside the contactor. However, in doing so, it will protect the primary ... |
how do laboratories find out what chemical that random sample is? | They have plenty of methods. Let's go with gas chromatography:
Vaporize your liquid and inject it into a gas chromatograph (a long column coated with an inert substance). The test substance moves through the column, interacting with the inert coating, causing the various chemicals inside it to separate out (as some "stick" to the coating and move slowly through it, while others just flow right through).
A detector at the end senses when each component comes through, and compares the time with the time of other chemicals on a database (for example, chemical x took 7.03 seconds to emerge, which matches up with chemical A on the database - therfore x is A).
It's not 100% accurate, since some chemicals will take 7.031 seconds and others 7.029, so if both are present, one will "hide" behind the other and it'll be difficult to distinguish between them. But the guys who do this are pretty smart, so they'd figure chemical x is more likely to be carbon than uranium (using completely random examples there). | [
"Chemical tests use reagents to indicate the presence of a specific chemical in an unknown solution. The reagents cause a unique reaction to occur based on the chemical it reacts with, allowing one to know what chemical is in the solution. An example is Heller's test where a test tube containing proteins has strong... |
How was literacy in colonial America leading up to the revolutionary? | So, this really depends on where in colonial America you are talking about. It's really important to understand that there were deep geographical differences in colonial America. In New England, during the eighteenth century, the literacy rates were upward of 90%. This has a lot to do with the Puritan influence in New England, which required that everyone be able to read the Bible. The literacy rate in the South was lower, being around 80% in South Carolina, for instance. This does not include slaves, however, so if you are including the entire population, the numbers are lower. So, most people probably would have been able to read the pamphlets you're talking about.
Many people, however, may not have actually read it. Colonial America was still very rural and agricultural, which meant that it took a little while for literature to penetrate into the countryside. And the language may well have been obtuse to most people. By and large, these pamphlets were directed at what we might think of as the middle and upper classes, which were in the minority then as they are today. It's a mistake to think that, just because they may not have read it, people weren't familiar with the ideas. People were talking about these issues at the common level.
There is an argument, however, that the ideology of the revolution was not as influential in kicking of the whole thing as the economic problems. Woody Holton has argued that the elite of Virginia, like Washington and Jefferson, didn't really want a revolution, but were pushed into it by the lower classes. Essentially, the new taxes and laws that Great Britain passed hit the lower classes disproportionately hard, and that the lower classes were the ones really pushing for revolt, rather than the idealistic upper class. While I personally find his argument incredibly persuasive, there's little doubt that the revolutionary ideals trickled down to all levels of society. There's even quite a bit of evidence that the American Revolutionary ideas even got as far as the slaves in Haiti.
Sources: F. W. Grubb, "Growth of Literacy in Colonial America," Woody Holton, *Forced Founders*, T. H. Breen, *Marketplace for Revolution*. | [
"Colonial America in the 1700s saw an expansion in printing industry, precipitating a culture shift from the idea that only the wealthy should have access to books and to education, to the premise of equitable access to education and books for all society. Earlier, in 1638, Harvard University established the first ... |
what is white feminism? | The term is usually used when white women(mainly from higher economic classes) fight for gender equality while not being invested/interested in fights that other women face, like racism for women of color, homophobia for queer women and transphobia for trans women. | [
"White feminism is an epithet used to describe feminist theories that focus on the struggles of white women without addressing distinct forms of oppression faced by ethnic minority women and women lacking other privileges.\n",
"White feminism portrays a view of feminism that can be separated from issues of class,... |
Which offers a more "realistic" sound reproduction, high quality headphones or high quality speakers? | It depends on the recording.
Most modern music is made by recording instruments individually and mixing them together, with plenty of effects and some electronic instruments added in. There's actually no realistic way to listen to this music since the composite sound never existed on its own to be recorded. Asking how to get a realistic representation of this music is like asking what kind of TV gives you the most realistic representation of The Simpsons.
Some recordings are made with stereo microphones in a sound field. Many classical and jazz recordings are made this way. Since these are recordings of real sounds, it's possible to achieve a more realistic reproduction. Since the microphones intercept the sound field, speakers that reproduce that sound field will be your best bet for a realistic listening experience.
Headphones aren't usually good for realism for stereo recordings because they wrap the sound field around your head and you lose location information. The sound appears to come from the center of your skull, and it moves when you move your head.
The most realistic recordings however, are meant to be listened to with headphones. They are called binaural recordings. Binaural recordings are made with a dummy head that has microphones embedded in the ears. This captures all of the subtle details that result from the shape of a person's head and ears. Good binaural recordings are scarily realistic when listened to on quality headphones. | [
"Most designs produce high quality sound, even though some audiophiles consider chip-based amplifiers to be inferior to their discrete counterparts. The chips have been designed to incorporate a number of desirable features, including excellent power supply rejection ratio, fast response, accurate bias current, ove... |
Does exposure to bacteria increase the immune system? | Yes, that is what the adaptive immune system is all about.
For many things exposure to bacteria is necessary for a proper development. Things like immune function and GI development are often used as examples (in mice and zebrafish) as sterile (no germs) raised individuals lack the development seen in ones with regular exposure.
Additionally a paper last year showed that after feeding a soil living bacteria to some mice their serotonin levels in creased and they did better on a maze or memory task then mice who were not fed the bacteria. The effects lasted for 2 weeks after the bacteria had been wiped out (hinting at an enzyme or mRNA mediator) | [
"The microbial communities residing inside the host body have now been recognized to be important for effective immune responses. Yet the molecular mechanisms underlying this protection are largely unknown. Bacteria can help the host to fight against pathogens either by directly stimulating the immune response or b... |
why do featurless/emotionless faces create feelings of unease and fear? | There is a great video from Vsauce about the "uncanny valley": _URL_0_
Basically, things that don't look at all like humans don't cause any special emotions by themselves. As things begin to look more human, they become more "friendly", and "ususal".
Imagine a curve in a graph going up, and up... Until it drops drastically at a point where something very closely reassembles a human... Although it isn't. That is the uncanny valley. Masks, clowns, corpses, statues, robots, toys - all of these have the potential to look very similar to a person, and yet there's something not quite right. So your mind is prepared to trust the thing as a person... And then it takes a few steps back when it realizes it was deceived. | [
"According to psychology professor Joseph Durwin at California State University, Northridge, young children are \"very reactive to a familiar body type with an unfamiliar face\". Researchers who have studied the phobia believe there is some correlation to the uncanny valley effect. Additionally, clown behavior is o... |
What are the relative efficiencies of resting if I can't fall asleep? | Psychiatrist here. No. You can rest, but you cannot substitute for sleep. In fact, if you can't sleep, just laying there after a while is countertherapeutic, as you start allowing your brain to do other activities in bed at night instead of sleeping. Good sleep hygiene involves getting up after you've tried sleeping, doing a non stimulating activity for a while until you are tired again (NOT reddit or TV or video games which compel further use... Open ended stuff like reading a long novel or working on athe soothing craft project.) then try to sleep again. Rinse. Repeat.
One of the best resources for sleep hygiene that I've come across and give to all my patients.:
_URL_0_ | [
"BULLET::::- Get enough rest. Rest allows body tissues and joints the time they need to repair. Sleeping is a great way to maintain health and helps both body and mind. Lack of sleep, stress levels and symptoms might get worsen. Immunity to other infections or diseases is reduced when sleep is not adequate. Rest co... |
floating | It's all about density.
As an object enters water, it displaces some of the water proportional to its *volume*. For example, a cube one meter per side will displace exactly 1 cubic meter of water when fully submerged.
However, as you submerge an object, the water pushes back up on it, and it turns out that the force that the water exerts is exactly equivalent to the *weight* of the amount of water that the object has displaced.
So if an object can managed to displace enough water to match the weight of the object, and if it can do this before it is totally submerged, it will simply stop sinking. It will float.
Now, ships may seem kind of odd, because there's a lot of steel construction, and still obviously sinks, being much denser than water. However, most of the volume of the ship is actually air, so the entire ship taken as a whole is actually less dense than water, and thus it float. | [
"The term floating island is sometimes used for accumulations of vegetation free-floating within a body of water. Due to the lack of currents and tides, these are more frequently found in lakes than in rivers or the open sea. Peaty masses of vegetable matter from shallow lake floors may rise due to the accumulation... |
For being one of thegreatest civilizations that this world has ever seen, how did the Indus or Harappan civilzation end? | I feel like there has been a bubble of references to the Indus Valley/Harappan civilization (just called "IVC" from here on) this week. Was there a documentary on it or something? Regardless, I'm glad you brought the question here because there is an enormous amount of disinformation on it. The IVC exists in the center of a Venn diagram of nationalism, orientalism, and lack of good information. That even the greatest experts on the topic have difficulty answering very basic questions means that statements taken out of context, uninformed and incautious speculation, and outright falsities spread very quickly.
I need to qualify this because, generally speaking, when people talk about the IVC they do so divorced from other cultures at the time. Our ignorance of it is not so much greater than that for, say, Minoan Crete, where we face many of the same issues, and we know considerably more about the IVC than about, say, the Sanxingdui Bronze Age culture of Sichuan (in fact, we only know marginally more about pre-Zhou Bronze Age China in general). The reason scholars stress their ignorance of the IVC is because we lack the crucial element of greater cultural context. We may not know much about the Minoans, but we know a great deal about the context of the eastern Mediterranean and can make inferences about that. Our ignorance about pre-Zhou China is profound, but we know a great deal about what came after. The IVC exists in a vacuum. People have made heroic attempts to connect it to later accounts in Iron Age Indian literature, like the Vedas and Upanishads, but to no real avail. Every solution raised by this method contains so many difficulties that most scholars choose to simply avoid it altogether. The IVC exists almost within a vacuum, and the paltry connections found to contemporary Mesopotamian civilizations leave us with frustratingly little.
People also often look at its seemingly impressive advances as divorced from other advances at the time. The IVC's city planning and sewage system were quite impressive, but such things were far from unheard of at the time--the Minoan colony at Akrotiri has city planning and sewage as well. The IVC may have had more "advanced" in these matters, but such things are rather difficult to prove when looking at 3500 year old brickwork. Oftentimes therefore the statements about the impressive IVC remains come with the implicit suggestion that the rest of the work was just hitting themselves over the head with rocks to pass the time, which I think is [just a](_URL_0_) [trifle](_URL_1_) [unfair](_URL_2_).
This is not to deny the impressive scale of the IVC. Something very remarkable and very interesting was going on in the Indus Valley during the bronze age. But it is unfair to the civilization to throw unwarranted speculation and hyperbolic figures at it, or to co-opt it either for our political, nationalist, or ideological advantage or our orientalist fantasies.
Now, to answer your question, the IVC is usually said to have collapsed due to a confluence of climatic and other natural factors, which may have exacerbated social stresses caused by, or leading to, internal or external conflict. This is archaeologist speak for "hell if I know". | [
"Previously, scholars believed that the decline of the Harappan civilisation led to an interruption of urban life in the Indian subcontinent. However, the Indus Valley Civilisation did not disappear suddenly, and many elements of the Indus Civilisation appear in later cultures. The Cemetery H culture may be the man... |
why is gum brittle at first, then stretchy? | The elastic, chewable properties of bubble gum come from the other ingredients, such as polymers, plasticizers, and resins that act as stabilizers. These ingredients give bubble gum its texture and elasticity.
When gum is made, these ingredients are in a "sleeping" state and when you start chewing your saliva and teeth "wake them up" causing the gum to become more like rubber. | [
"A cracker is a flat, dry baked food typically made with flour. Flavorings or seasonings, such as salt, herbs, seeds, or cheese, may be added to the dough or sprinkled on top before baking. Crackers are often branded as a nutritious and convenient way to consume a staple food or cereal grain. \n",
"The viscosity ... |
"dolby surround sound". how it's different than normal surround sound? | [Dolby](_URL_0_) is a company which designed a system for surround sound. When something says Dolby surround sound, it simply means that it uses that companies technology. | [
"In the motion picture industry, as far as it concerns distribution prints of movies, the Dolby A and SR markings refer to Dolby Surround which is not just a method of noise reduction, but more importantly encodes two additional audio channels on the standard optical soundtrack, giving left, center, right, and surr... |
Is there a lifeform which does not use DNA/RNA for its genetic code? | I’ve taken more genetics courses and read more genetics papers than I care to admit to, but I’ve never heard of such a thing. DNA/RNA is one of the basic necessities of life. Are you sure you didn’t read a paper that was extrapolating the idea of DNA-less life? | [
"Even the simplest members of the three modern domains of life use DNA to record their \"recipes\" and a complex array of RNA and protein molecules to \"read\" these instructions and use them for growth, maintenance and self-replication. The discovery that some RNA molecules can catalyze both their own replication ... |
Why was the Golden Horde called like this? | According to John Man^1 it was called this as Genghis's family was known as the 'Golden Clan', and the Mongolian word ord/orde meant a palace, or for the Mongols a tent. Hence Batu's (initial leader of the khanate) apparent use of a gold coloured tent as his 'palace', and the shift of ord/orde to horde led to the khanate being called the Golden Horde.
Worth noting that initially it was known as the Khanate of Qipchak^2 (named after the nomads who previously inhabited that area) and according to David Morgan the popularization of Golden Horde came about later.
---
^1: The Mongol Empire, John Man
^2: David Morgan, The Mongols | [
"The name Golden Horde is said to have been inspired by the golden color of the tents the Mongols lived in during wartime, or an actual golden tent used by Batu Khan or by Uzbek Khan, or to have been bestowed by the Slavic tributaries to describe the great wealth of the khan. But the Mongolic word for the color yel... |
What did people in the 1800's use as conversational fillers (i.e um, you know, like) ? | This recording of Thomas Edison from 1906 is full of "uh" as conversational filler or "verbal disfluency". It doesn't sound much different than speech today. I'll see if I can find an earlier recorded example
_URL_0_ | [
"Diseuse (, ), French for \"teller\", also called talkers, storytellers, dramatic-singers or dramatic-talkers, is a term, at least on the English-speaking stage, that appears to date back only to the last decade of the 19th century. The early uses of “diseuse” as a theatrical term in the American press seem to coin... |
What kind of currency was in mesopotamia? | The Mesopotamians didn't really use "currency" as such, which we can define as a centrally issued object having the function of store of account, medium of exchange and measure of value. In short, they did not have coins. But they did have standardized systems of weights and measures that, in practice can fulfill one or the other functions of currency. In Sumerian documents for example you will see value expressed in units of silver even if no silver is involved in the transaction. Currency in the form of coinage does not really come into being until the Iron Age in Anatolia, and it was taken up by the Persian Empire. | [
"Korean currency dates back as far as the Goryeo dynasty (918–1392) when the first coins were minted. The coins, cast in both bronze and iron, were called \"tongbo\" and \"jungbo\". Additionally, silver vases called \"ŭnbyŏng\" were widely used and circulated as a currency among the aristocracy of Goryeo.\n",
"A ... |
who decides if art is 'good' and what it's worth? | Usually it's based on the body of work of the artist.
For example, by the end of his work life Joan Miró was placing a single stripe of paint on a canvas and these are very prized even though *anybody* could place a stripe of paint on a canvas.
Like he'd stare at the canvas for a while and then in one fluid movement put a single stroke down and he'd love it and everyone else would love it.
This is because he spent his whole life evolving from being a talented painter that you'd probably call "normal" (i.e. he made pretty pictures with paint) to becoming a more and more abstract painter.
He kept reducing the complexity of his forms to see how to express emotions and form in an ever increasingly abstract way so that after decades of doing this he had developed a kind of language of form that was uniquely his.
So if you're aware of his progression and have an understanding of how to "read" his abstraction you can see how his single stripe of paint has meaning and is different and special compared to a stupid stripe of paint that just *anyone* could do. | [
"Components of a work of art, like raw stone, tubes of paint or unpainted canvas, in general have a value much lower than the finished products, such as a sculpture or a finished painting. Also, the amount of labour needed to produce an item does not explain the big price differences between works of art. It seems ... |
how can amazon prime carry / get any item anywhere in the world within 24 hours? | It can't and it doesn't
Amazon prime provides free *two day* delivery for *many* items in *many* locations. There are a fair number of locations where Amazon Prime gets you free *three to five day* shipping rather than two day
Amazon does not proclaim that you can get any item anywhere in the world within 24 hours. | [
"In 2005, Amazon announced the creation of Amazon Prime, a membership service offering free two-day shipping within the contiguous United States on all eligible purchases for a flat annual fee of $79 (), and discounted one-day shipping rates. Amazon launched the program in Germany, Japan, and the United Kingdom in ... |
Why do historians reject moral presentism? | Presentism does not facilitate or encourage an answer to (one of) the main historical question(s): "Why did these people do what they did?... what led them to that train of thought and chain of actions?"
History seeks understanding and comprehension, and that is best achieved in many cases by viewing the world *not* through the hind-sight of 21st century righteousness, but by trying to view and understand people and events in the contexts of their own times, places, and actions.
Sure, it's easy enough to say, "but Naziism was bad." Pretty low fruit, that. But what about... other historical questions? What happens if and when we start breaking off from the Modern Western morality spectrum altogether?
What happens when we start asking why Genghis Khan felt justified in doing what he did? Is a 21st Century "well, killing is bad and inhumane" presentist viewpoint going to help or hinder that answer? Or how about if we ask into An Lushan's justifications for killing 2/3 of the Chinese population in the 8th century? Or Alexander the Great's justifications for invading half of Asia?
Presentism isn't helpful because it is essentially a moral judgement. That's not helpful to history because history seeks to understand *how* and*why*, rather than seeking to place arbitrary blame against those who are no longer capable of explaining or defending themselves or their actions, in many cases.
Judging an ancient battlefield or political tangle from a modern perspective will render judgement, to be sure... but in doing so it will warp what actually happened and *why* it happened beyond any actual comprehension or meaning. | [
"Presentism is also a factor in the problematic question of history and moral judgments. Among historians, the orthodox view may be that reading modern notions of morality into the past is to commit the error of presentism. To avoid this, historians restrict themselves to describing what happened and attempt to ref... |
What are the consequences of missing a full night of sleep, if you make up for it by sleeping more the next night? | During sleep, the brain clears away toxic waste products which accumulate during the day. One of these products is beta-amyloid, the protein involved in Alzheimer's disease. It's been found that a single night of sleep deprivation greatly increases beta-amyloid ([source](_URL_0_)). In the long run, it could potentially increase Alzheimer's risk. | [
"There is a small amount of evidence that skipping a night's sleep may improve depressive symptoms, with the effects usually showing up within a day. This effect is usually temporary. Besides sleepiness, this method can cause a side effect of mania or hypomania.\n",
"Sleep is known to be cumulative. This means th... |
How was Hitler able to build such a massive and powerful army during the great depression? And why didn't France and England stop him? | The post-WW1 Reichswehr did not generally agree with the bounds of the treaty of Versailles, but its commanders (like Hans von Seeckt) did their best to abide by the letter of the law while maintaining the basic structure of a capable army.
For one thing, the General Staff was officially abolished, but went underground as the Truppenamt (Troop Office) for most of the interwar years. The army itself was limited to 100,000 men, which von Seeckt organized into 7 divisions. When the prewar officer corps was severely purged to a significantly smaller number, the army generally chose to retain men born within a certain time period, neither too old nor too young, with an eye toward expansion once the 'unjust' treaty was done away with. The junior officers and NCOs of the interwar Reichswehr were eventually to serve as an elite cadre around which the later Wehrmacht would form.
As for the French and British, they had other priorities during the interwar years, and were none too keen on another European war. Some people within Britain (including, arguably, Edward VIII) did not regard Hitler as a threat in the prewar years. The German military did expand, secretly at first, but later openly when no protests came. The Rhineland was reoccupied with only the slightest complaint from France and Britain, so it's no real surprise that the Germans believed they could get away with anything. Until the French and British made good on their guarantee of Polish independence, those Germans were right. The Allies did nothing about the Anschluss of Austria, the Czech cessation of the Sudetenland, and eventually Neville Chamberlain came home after the total annexation of Bohemia with a piece of paper bearing Hitler's signature proclaiming "Peace in our time!". | [
"Hitler followed an autarky economic policy, creating a network of client states and economic allies in central Europe and Latin America. By cutting wages and taking control of labor unions, plus public works spending, unemployment fell significantly by 1935. Large-scale military spending played a major role in the... |
Do black holes have a "surface"? | The answer to your question lies somewhere between "no" and "we can't know".
If the [no-hair conjecture](_URL_0_) holds, there's nothing you can know about a black hole except for its mass, angular momentum and charge. You're not allowed to know anything about the mass distribution within the black hole, and hence if there is a surface in there. In general relativity, the general assumption is that there is no surface, just a spacetime singularity. We don't yet know how this fits with quantum mechanics, but we'll have to wait until a theory of quantum gravity is established. | [
"A widely used model of a black surface is a small hole in a cavity with walls that are opaque to radiation. Radiation incident on the hole will pass into the cavity, and is very unlikely to be re-emitted if the cavity is large. The hole is not quite a perfect black surface — in particular, if the wavelength of the... |
The Roman Architecture was heavily influenced by the Greeks, but were the Greeks themselves influenced in this area by other civilizations? | As far as Classical Greece goes, much of it was an indigenous development within the confines of that historical period, but it does build upon earlier foundations, which are also Greek, but not considered part of Classical Greece, namely Mycenaean and Kretan architecture. Mycenaen architecture largely seems to have been an indigenous development as well, and appears in such similarity to the very inception of architecture in the neolithic that it is amply clear that it would rather have developed from neolithic precursors than external influence. If I recall correctly, however, there are some theories which trace its origin to the Balkans - I'm not sure about the merit these theories deserve.
Minoan, that is Kretan, culture was subject to Egyptian influences, which reflected in aesthetics and architecture, although Krete remained very distinct from Egypt in both fields. | [
"The architecture and urbanism of the Classical civilizations such as the Greek and the Roman evolved from civic ideals rather than religious or empirical ones and new building types emerged. Architectural \"style\" developed in the form of the Classical orders. Roman architecture was influenced by Greek architectu... |
Why would an individual phospholipid switch sides in a phospholipid bilayer? | The two surfaces of a typical cell membrane have very different lipid compositions because they need to have different physical properties. For example the outer surface of a mammalian cell's plasma membrane has mostly charge-neutral lipids, and thus presents am inert surface to the outside world. Good for preventing unwanted interactions, perhaps. The inner surface has many negatively charged lipids which are the site of interaction for proteins that need to interact with the inner cell surface. The proteins that flip lipids across the bilayer are called flipases (seriously). | [
"The phospholipid bilayer is formed due to the aggregation of membrane lipids in aqueous solutions. Aggregation is caused by the hydrophobic effect, where hydrophobic ends come into contact with each other and are sequestered away from water. This arrangement maximises hydrogen bonding between hydrophilic heads and... |
Are humans, by preserving the weaker members of our species, hurting our evolution? | Evolution selects the individuals who are most fit for their environment. This is not always the most physically imposing specimen (ask the T-Rex how that worked out) but rather one who is able to survive under the given circumstances.
Since humans are a highly social species our "circumstance" consists largely of other humans and our mental capacity is far more valuable to our survival than pure physical might.
The average IQ has been increasing over the decades so it would appear we're going in the right direction. Brute strength is no match for human ingenuity.
If it's any consolation, the *homo* genus has been selecting intelligence over strength for several million years, this isn't a new phenomenon. | [
"Opponents also cite that the genetic health and social behaviors of species is adversely affected because hunters often kill the largest or most significant male of a species. The removal the most significant animals (because of the size of their horns or mane for example) can severely affect the health of a speci... |
how is power generated in antarctica during polar night? | same way it's generated during the rest o the year. big ass diesel generators and wind turbines.
_URL_0_ | [
"Each station uses diesel fuel to generate electricity. At McMurdo Station, wind turbines installed by Antarctic New Zealand in 2010 supply about a third of the station’s electricity in a cooperative agreement with ANZ. Field camps have been increasingly using solar power, taking advantage of the 24 hours of daylig... |
Are there groups of animals where "A and B can have fertile offspring", "B and C can can have fertile offspring", but "A and C cannot"? | [Ring Species](_URL_0_) sounds like what you're asking about. From the page:
> a ring species is a connected series of neighbouring populations, each of which can interbreed with closely sited related populations, but for which there exist at least two "end" populations in the series, which are too distantly related to interbreed | [
"The sister species \"Drosophila subquinaria\" and \"Drosophila recens\" overlap in geographic range and are capable of hybridization, meaning they can successfully reproduce with each other; however the offspring are very sickly. Thus, these two species are almost fully reproductively isolated, despite overlapping... |
Are artificial satellite's orbits disrupted by the moon? | Yes, absolutely. When planning the orbit of a spacecraft, the gravitational fields of the Moon, the Sun and even the other planets can be taken into consideration. For an Earth orbiter, the non-spherical shape of the Earth also significantly affects the orbit. Solar radiation pressure is another major component of the force model.
The higher the orbit of the spacecraft, the more significantly the Moon (and Sun) will affect the orbit. Similarly, accounting for the non-spherical gravity field of the Earth is more important the lower your spacecraft's orbit.
As a source, I picked an low Earth orbiter, ICESat, which measured the topography of the ice sheets, oceans, and the globe in general:
_URL_0_
"ICESat’s repeat groundtrack orbit was designed using a disturbing force model that includes only the Earth geopotential. Though the third body effect from the Sun and the Moon was neglected in the orbit design, it does in fact disrupt the repeatability condition of the groundtrack and consequently implies orbit correction maneuvers. The perturbations on ICESat orbit due to the third body effect are studied as a preliminary work towards including these forces in the design of the future ICESat-II repeat groundtrack orbit."
While ICESat's orbit may have been planned without considering the Moon's gravity, for precise orbit determination, an accurate force model-- including the Moon's gravity-- is vital.
edit:
The force on a spacecraft can be divided into components: the force due to the Earth's gravity plus the force due to the Moon's gravity plus...
F_total = F_earth + F_moon + F_sun + ...
It's a continuum, with the importance of each component depending on where the spacecraft is. On one hand, you have ICESat, whose orbit was planned without even considering the moon...on the other hand, you have spacecraft like Artemis, whose orbit doesn't even exist, can't even be approximated, without considering the Moon's gravity: _URL_1_ | [
"Lunar mascons alter the local gravity above and around them sufficiently that low and uncorrected satellite orbits around the Moon are unstable on a timescale of months or years. The small perturbations in the orbits accumulate and eventually distort the orbit enough that the satellite impacts the surface.\n",
"... |
in movies, how do they film in governmental areas (ex. the capitol and the white house)? | I'm not sure, but I think it's either with a green screen or a custom built movie set
Edit: here's an example of what amazing things you can achieve with a chroma key (green or blue screen) and some talented artists: _URL_0_ | [
"In many cases a second unit is dispatched to film on location, with a second unit director and sometimes with stand-in actors. These shots can then be edited into the final film or TV program alongside studio-shot sequences, to give an authentic flavor, without the expense or trouble of a full-scale location shoot... |
What was the Egyptian military like in World War 2 and after? | Hate to be needy, but Ill ping some of the relevantly flaired users:
/u/JoelWiklund /u/BeondTheGrave /u/British-Empire | [
"In 1914 the Egyptian Army was a largely native home-defence force. It comprised 17 battalions of infantry (8 Sudanese and 9 Egyptian), 3 companies of mounted infantry, a Camel Corps, support services and various local militia groups. It was organised, expanded and equipped by the British during the prewar years, a... |
How did they discover that Europa had liquid oceans underneath its ice? | The short answer is that geologists sat down and created models to show how the surface features could be created by tidal movement.
A person I've had the pleasure of working with over the years is, quite literally, the top authority in the world on this specific subject. He was the one who discovered this. I was just chatting with him, and he provided this insight as well:
"The real smoking gun was that the magnetometer on Galileo measured a dipole during close flybys of Europa. If Europa has an ocean (with salts) then an induced magnetic field should be detectable. And it was"
I'm trying to see if he can create an account and provide a more detailed answer. | [
"It is estimated that Europa has an outer layer of water around thick; a part frozen as its crust, and a part as a liquid ocean underneath the ice. Recent magnetic-field data from the \"Galileo\" orbiter showed that Europa has an induced magnetic field through interaction with Jupiter's, which suggests the presence... |
What were the Germanic "Tribes" really like? Were they nomads without cities? Or were they more sedentary like Rome? | Romans wrote a lot of BS about 'the Germanic tribes', mostly because they defined 'Germans' as 'those who are not like us and who live outside the borders of the empire'. This definition lumps quite a lot of people together, while still throwing in loads of cultural bias as well.
It is much more interesting to look at 'people who lived outside the Empire' outside of their classification as 'Germanics'. We then see that settlements change over this time period. In the centuries BC (and up to 200 or so), the regular person would live on his own farmstead, within viewing distance (or walking distance) of his neighbours. A farmstead would have its own fences, wells, and outbuildings and would generally be mostly self-sufficient, though some regional specialisation (some areas focused on cattle raising, some on cereal cultivation etc.) did take place. Some areas that were particularly suitable for resource exploitation (close to forest for suitable timber, or close to iron ores for iron mining, or near the sea for salt extraction, or near a peat bog for peat digging) did have this 'industry' as a household activity 'on the side', but this is secondary to the main function of the household as a farm.
Around the 2nd century or so, the village (collection of farmsteads) becomes more popular. While villages did exist in the earlier period as well (but were not the norm), the village of the late roman period becomes more common and more formalised. We now see a collection of these farmsteads. Archaeologists have tried to make statements about elite dominance within these farms on the basis of the size of the stable (and hence the capacity for cattle, and hence wealth), but this is very difficult. Generally, it seems that farms within a village were 'equal'. This does not mean that everyone within the village was equal, just that everyone lived in the same kind of house. It is also later, in the Migration period, that the size differences between households within a village gets more expression, and the larger farmstead collects also more small outbuildings, including a temple and more craft workshops. The first of these is Gudme in Denmark around the year 200, but by 400 these kind of places exist in many regions.
Parallel to this, you should also keep in mind that in the south of 'Germania', in modern Southern Germany and Austria, village organisation had already taken place in much earlier periods, including task differentiation between households.
We can see no traces of nomadism in Germany, the Netherlands and Denmark in this period. They did travel to cattle grazing grounds in the summer, but this type of seasonal movement, called transhumance, is restricted to cattle herders, and not common within society in general. It is also highly regulated and occurs within fixed 'grazing areas', relatively close to the stationary 'home base', and not at all 'migratory'.
Farms (and hamlets) also did move around within a landscape, so a field that in one decade might have been used for grain, might become a building plot a decade later, and grazing lands 30 years after. However, this cycle of rebuilding the farm (related to pest control) also happens within a local area. | [
"Ultimately, the Germanic groups in the Western Roman Empire were accommodated without \"dispossessing or overturning indigenous society\", and they maintained a structured and hierarchical (but attenuated) form of Roman administration.\n",
"Early Roman sources, such as Tacitus and Pliny the Elder, knew little co... |
Why are camera lenses the size they are, and why can't they be scaled down to phone-size? | Miniaturizing the fancy lenses on SLR cameras would be a lot of work—they require extremely precise optical glasswork and tons of fiddly mechanical gizmos for focusing and such.
The really insurmountable difference between big cameras and small ones, though, is sensor size. The sensors used in digital cameras have tiny electronic "photosites" which convert photons into electrons. Making these smaller has a serious adverse effect on the quality of the images you can produce, for physics reasons.
There's nothing magical about the 35mm size, of course. That just happens to be the size of the imaging region of standard photographic film, so lots of equipment was made to that standard for a very long time. When digital SLR cameras hit the scene, photographers and manufacturers wanted to keep using their old lenses, so they kept the same physical layout and just replaced the film with a digital sensor of comparable size. | [
"Larger lenses may block a portion of the view seen through the viewfinder, potentially a significant proportion. A side effect of this is that lens designers are forced to use smaller designs. Lens hoods used for rangefinder camera may have a different shape to those with other cameras, with openings cut out of th... |
how are games "ported" to mac or linux? | Rewriting any code that's locked to a particular system to work for the other ones. The OS has 'toolboxes' for things, but each OS's is a different. You have to rewrite to use the other tools. | [
"However, there are many ports of games from other platforms, mostly Linux, to the GP2X. Popular ports include \"SuperTux\" and \"Frozen Bubble\" as well as the \"Duke Nukem 3D\", \"Quake\", and \"Doom\" engines (which can run the original games if the user owns a copy with the correct data files). There are also h... |
How do you weigh a blue whale in the ocean? Some kind of device or math? | By the Archimedes' principle, a buoyant body (that is, stationary without expending energy to remain that way) submerged in water, is equal in mass to water of equal volume to the part of the body submerged underwater. For fully submerged bodies, that means it's mass is equal to the mass of the water of equivalent volume.
Since a blue whale can remain stationary underwater, it follows this principle. By approximating the volume of the whale, we can calculate it's mass by calculating how massive is water of equivalent volume. In open ocean, exact volume calculation could be difficult, but a reasonable estimation is possible with visual means.
For more controlled environments such as a large swimming pool (not applicable to a blue whale, but applicable to orcas or dolphins), a more precise volume approximation may be done using another law attributed to Archimedes, the Equal Displacement rule, stating that a body submerged in water displaces an equivalent volume to its own. By measuring the height of the water with and without the animal, we can calculate the animal's volume, and then proceed with the Archimedes' principle above to calculate it's mass. | [
"The craft weights 2,100 kilograms out of water and is 7 or 8 meters long according to type. It resembles a torpedo but has two cockpits for the crew. Many some models have a roof with sliding doors for the cockpits. In some models the rear cockpit is long and can seat two divers for a total crew of three. Its batt... |
truecrypt full disk encryption/decryption | Hi there! I use this at work. I'll give it a super ELI5 shot:
Imagine your friend wrote a paper in Swahili and gave it to you. Cool, but you don't speak Swahili. So what he did was also send you the phone number to a guy who *does* speak Swahili. You call him up, he comes over, and he reads the paper aloud to you. That's how TrueCrypt works.
Paper in Swahili - HDD with encrypted data **written down**. This is the important part, that it's only written down in encrypted format.
Guy who speaks Swahili - TrueCrypt. For the purposes of this analogy, we'll say that lots of people speak Swahili, but only if you call them up using that exact phone number will any of them actually talk to you. He can turn the Swahili into data you can use. This is TC turning encrypted data into useful data 'on-the-fly' as it says in that document.
Phone number - Code that you use to "mount" the TrueCrypt volume.
Guy reading it aloud - Loading the encrypted data into RAM. Notice that the guy is reading it aloud to you and it's going into your head. This means that there is **no** decrypted copy in long-term storage anywhere. This is important. It's not like the guy copies the paper into a language you do understand and leaves it for you. With this, you *have* to have a Swahili-speaker to use it, and there is no decrypted copy anywhere but in your head (and his, but his memory sucks).
Now, what about the other way? Sure. When you write to a TrueCrypt encrypted volume, you're dictating in English to a guy who writes it down in Swahili. Only if you have the phone number to get this guy again can you get it back out. Same deal, there is no unencrypted copy anywhere.
Basically, TC is a magic door that makes everything passing through one-way gibberish, and turns everything passing through the other way from gibberish to useful data.
Did that help at all? | [
"Expressions \"full disk encryption (FDE)\" or \"whole disk encryption\" signify that everything on disk is encrypted, but the master boot record (MBR), or similar area of a bootable disk, with code that starts the operating system loading sequence, is not encrypted. Some hardware-based full disk encryption systems... |
If one HotPocket takes two minutes to cook in a standard microwave, will two HotPockets take more time, less time, or the same amount of time? | For microwave you will have an increased time.
The food will have to absorb twice the energy.
Some energy will be lost in the oven itself. Also microwaves are not good at penetrating water and will only be good at heating the top layers. So that can case some water to evaporate. (Lost heat)
But in general you will need to supply twice the energy to heat twice the mass of food.
Some exceptions apply like tiny food stuff that only gets hit by very few waves and causes the loss to occur inside the over mostly.
P.s.: I have no clue what a hot pocket is ;)
| [
"In addition, hot food must be held at a minimum interval of 135°F (57°C) if it is not immediately consumed. The temperature must be checked every 4 hours or else labeled with a discard time. Although monitored hot food can be held indefinitely in this way without a food safety concern, the nutritional value, flavo... |
Can you trap a beam of light inside a box? | Optical cavities exist but you have to keep in mind that no mirror is perfect and even if, say, a mirror reflected 99.9% of light, given a 1 meter cubed box, light would reflect 300 million times a second. So that means that after 10 microseconds there'll only be about 1% of that light left.
However, generally when we build an optical cavity we are continuously GENERATING new light within it and an optical cavity is a big part of, for example, the design of a laser. In this case it is by design that the light get out, rather than be reabsorbed and you don't want perfect reflection (though you do want really good reflection) but rather higher transmission than absorption | [
"Almost any item can be booby-trapped in some way. For example, booby trapping a flashlight is a classic tactic: a flashlight already contains most of the required components. First of all, the flashlight acts as bait, tempting the victim to pick it up. More importantly, it is easy to conceal a detonator, some expl... |
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