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cbyb5z | What are Octonions, and how are they useful? | To understand Octonions you need to start with the complex numbers. A complex number is a real part plus an imaginary part: a + b\*i, where i is defined as sqrt(-1) and i\*i = -1. Multiplication of complex numbers represents rotation in 2d, and has relationships with two dimensional vectors.
Step up the dimensional ladder and you reach the 4d analog of the complex numbers: the quaternions. A quaternion is a real part plus 3 imaginary parts: a + b\*i + c\*j + d\*k (each of i, j and k are called bases). Each of i, j, k, when multiplied by itself, is equal to -1, and the rest follow the equation `i^2 = j^2 = k^2 = ijk = -1.` Each time you go up the dimensional ladder for these analogs of complex numbers (so called normed divisional algebras) you lose an algebraic property: the complex numbers are commutative, meaning **c1\*c2** = **c2\*c1**. For the quaternions, this is no longer true. Unit quaternion multiplication represent 3d rotations, and the imaginary part of the quaternion relates to the 3d-cross product.
Step up the dimensional ladder again and you reach the 8d analog of complex numbers: the octonions. From now you probably can infer the pattern: octonions are defined as a real part plus 7 imaginary parts: `x1 + x2*e2 + x3*e3 + x4*e4 + x5*e5 + x6*e6 + x7*e7 + x8*e8`. I changed the notation here to a bit to match how octonions are usually written, but it's mostly just because after a few consecutive letters it's easier to just identify things by their index instead of remembering "is that one m or n". Any `en^2` = -1, with a defined table for multiplying between different basis. As we saw with quaternions, we lose another algebraic property. This time we lose associativity, so **O1**\***O2**\***O3** does not necessarily equal **O1\*(O2\*O3).** Unit octonions correspond to 7-dimensional rotations and the imaginary part relates to the 7 dimensional cross-product. If you are versed on the cross product, you'll know they only are defined in 3 and 7 dimensions, this is not a coincidence but has a relation to the quaternions and octonions.
As it turns out, that's as high as you can go on the dimensional ladder for the traditional extensions to the complex numbers in this way: the normed divisional algebras. You can go further by specific constructions, giving the 16-dimensional sedonians and so on, but they have fewer nice properties and are generally not often used.
& #x200B;
So that's a lot of words on what they are mathematically, when are the used? Largely group theory and abstract algebra. That's not my expertise so I can't give the super specifics, however I can talk about where they are being explored in science: particle Physics. There are attempts to reformulate the standard model in the language of octonians instead of tensors, and they seem to have some relation to supersymmetric theories. None of this is widely used now, however. Additionally, they are useful in a 7-dimensional space, analogous to how quaternions are useful to a 3-dimensional space.
& #x200B;
Here's an article on the quest for octonion descriptions of the standard model: [_URL_0_](_URL_0_).
& #x200B;
That's the best simplification I can do. They are an abstract concept by nature, and higher dimensional than we can visualize. | 72872d41-c2e0-4f4a-811e-f199c3a8ea05 |
cbyotm | Why do baby turtles crawl towards the sea after hatching? | They follow the light, which at night is usually the moon reflecting off the ocean.
In recent years, artificial lights have confused this instinct and caused some nesting sites to have very poor survival rates. | 743c38a7-3694-44ad-8820-1a0eda7f187a |
cbysh7 | What is CGRP? How does it cause migraines and how do new medicines stop it? | CGRP is a a protein. The brain and nervous system use this to “talk” about pain. Your body has certain reactions to being told there is pain, and one of these reactions is that your blood vessels can shrink down, and when the blood vessels in your brain shrink down it can cause or worsen a headache. This is part of the way ibuprofen (Advil) works on headaches too-it’s a vasodilator so it helps to re-expand the vessels.
CGRP drugs stop CGRP from transmitting, so you can’t get a migraine if your body isn’t being told to get a migraine. | 9bded8c1-cdb6-4ceb-9e5d-220f46d3ba16 |
cbyus9 | Why do prosecuters/courts seek/sentence prison time greater than the expected lifespan of the offender (i.e. 150 years in prison)? Why not simply sentence those criminals to 'life' in prison instead? | Sentencing options are written into state laws. Life in prison is different in state laws than 150 years. Some of it comes into play with the "cruel and unusual punishment" clause in the Constitution too. Life in prison may not be "cruel and unusual" for a murder sentence, but it might be for, say, child sex trafficking. But if you trafficked 10 kids and the sentence is 15 years for each one, you get an effective life sentence that will also stand up, Constitutionally, against a "cruel and unusual punishment" defense. | 5fc35a62-e254-4772-b4a2-7293e312ba20 |
cbyvv5 | Why does the sound of poured water gets higher and higher as you keep pouring? | Because the sound you're hearing is sound coming out of a round chamber. When the glass fills with water, the size of the chamber changes, so the pitch changes. Large chamber, low pitch. Small chamber, high pitch. It's why digieridoos are deep and rumbly while ocarinas are high pitched and whiny. | c76ee3a1-cef3-4a9e-a130-1bf89ca26b85 |
cbyw1w | How do hybrid cars work? (Simple version please!) | Hybrid vehicles are electric vehicles which use a gasoline motor to charge the battery.
Why do they do this?
Gas engines are designed to work well and most efficiently within a certain RPM range. In a typical gas car, this means that in order to keep the gas engine working in its "optimal range" as the car moves through various speeds, you need a transmission - gears that convert the engine's speed into the car's speed. Transmissions are complex, heavy, prone to wear and failure... so if we can do without one we're better off.
Electric motors have (to simplify things) the benefit that they work most efficiently across a wider range of speeds. So we don't need a transmission. But batteries (currently anyway) don't have the same energy density as gasoline. You'd have to recharge an electric vehicle more frequently than refil the same size / performance gas vehicle. And batteries are _heavy_.
so lets combine the strengths of both. We get simplicity of an electric vehicle, but we can reduce the size of the battery by adding a small gasoline motor that is only there to charge the battery. Oh, and to help the brakes we can recoup some of our electricity as we brake. | f413c433-2630-4390-a88b-e9e981a7dc71 |
cbz4bs | Why does some food, such as oatmeal, seems to get more nutrisious when it has been heated | You break down the cellulose and other indigestable material with heat. What's left can be broken down more thoroughly and more of it can be absorbed to be used by the body. Breaking the food down first makes more of it available to your body. | 754331dc-c5e9-43a6-9086-806275a33de5 |
cbz5d5 | What are nuclear shadows? | The intense heat of the atomic explosion caused what are called nuclear shadows. The blast changed the colors of surfaces like steps, walls, and pavement because of the UV radiation that was emitted. When things that were soon to be vaporized blocked whatever what was behind them, they didn't allow this UV color change to happen. And, as a result, outlines of people and objects incinerated in the bombing left haunting shadow imprints behind on such surfaces.
Source and images of nuclear shadows: _URL_0_ | 5cc6949f-154e-42e1-8415-69d526573f19 |
cbzamx | What happens when a child breaks his leg right before a big growth spurt? | A kid in my elementary school broke his leg before a growth spurt and they broke the other leg so that they would match. He missed the rest of the year and was in a wheelchair for a while. | 3acff619-d97d-4d7a-aaaf-d372590509d1 |
cbzbuo | why does slouching and bad posture feel so much better than good posture? | Not always but it's usually because your muscles are not strong enough to hold your body in the proper position. So basically your muscles are getting tired holding yourself up and when they relax it feels good. In the long term however, your bones and joints will deteriorate and cause a lot of pain. | ec4ed6f2-327e-4c64-992b-29e370cb8864 |
cbzqjp | When a part of the body aches, we as a reflex immediately apply physical pressure using hands. Why? | It's not instinctive, I don't think.
People have learned that if you rub a part of the body, this floods the nerves with sensation, and the nerves going to the brain can only carry so much signal at a time, so some of the signal is lost, meaning some of the pain signals don't make it to the brain and so it feels like the body part hurts less. | 44a73a84-d7d4-4091-8873-f158469d217b |
cbzqmx | What's the difference between interstate highways and US highways? | The Interstate Highway System was created with the [Federal Aid Highway Act of 1956](_URL_1_).
Before then, the "US Highway" system was an ad-hoc system of state/locally maintained highways that were funded partially through grants on a "matching" basis, where the Federal government would match state investment in whatever highway was being constructed. This system lasted from about 1925 until 1956, when the Interstate system was adopted.
The interstate system was different in that it provided for a [Highway Trust Fund](_URL_0_) that would pay up to 90% of the costs of the interstate highway, with the remainder funded by the state. This trust was funded primarily through a federal fuel tax on gasoline and diesel fuel.
Interstate Highways replaced some of the older US Highways, but quite a few routes still remain. The numbering system is largely maintained by the [American Association of State Highway and Transportation Officials \(AASHTO\)](_URL_2_) | f147e6ae-e335-4a12-9264-3445a664a53a |
cc0091 | How did the letter Z become associated with sleeping or snoring? | & #x200B;
"How and when did the letter Z become to be associated with sleeping?"
First of all, zzzz (or z-z-z-z) is sound of snoring, from at least 1918. (Sometimes "a tiny saw cutting through a log" \[1948\] would be used, and both the snore and saw would make the same z-z-z-z sound.) Over time, this became associated with sleep in general, but most comic reference books (e.g. 2006's *KA-BOOM! A Dictionary of Comic Book Words, Symbols & Onomatopoeia*, 2008's *Comic books: how the industry works*) still mainly associate it with snoring. | e769d028-9592-448a-8335-3fcb51bc3ca3 |
cc02dq | How do STDs form/ where do the originate? | STDs are just diseases. At some stage in their evolution they mutated, maybe one branch of their family tree spread by making victims cough out particles and others spread by sexual contact. There are pros and cons to each strategy, lots of coughs happen with nothing around and coughing people "seem sick" to their peers. On the other hand, sex isn't as frequent as coughing.
The diseases we call STDs today evolved from the branches that spread by sex. It's not a different disease concept, it's just a label humans put on STDs. | 680d814e-1382-4ec4-b8fc-5c0d5ee065c4 |
cc06ru | Why can't a steel chef's knife slice a piece of steel rebar? | Cutting is based on two things. Having enough force to break through the material you want to cut and using something tougher than the material so the material gets cut instead of bending what to are cutting with.
You cannot cut steel with a feather, applying more force causes the feather to bend not the steel to get cut, because the steel is harder than the feather.
Asteel knife is about as hard as rebar so it might scratch it. But applying more force will bend the knife because it is thinner and therefore weaker than the rebar | 77513b1d-5921-4d71-8193-f73c967a5417 |
cc09nm | Horror Motif in Literature | A motif is just a recurring concept or idea in literature, so, presumably, a horror motif is a motif that, in some way, shape, or form, instills horror. | 842f4a0e-f725-4ae5-a866-8bc8a865381b |
cc0ar2 | Why isn't all plastic recyclable? | It's all about cost. If you have pristine poly-carbonate packaging from a pharma factory that's been handled by skilled workers in a super clean factory - sure, that's easy to recycle for what it will sell for.
On the other hand, if you've got a plastic straw from the rubbish bin of a McDonalds with smudge-proof lipstick on one side, molding sugary soft drink on the other side = > that's not so appealing. Plus, if it's mixed in with even-less-recyclable food waste, separating it will cost more than the end product is worth. It could be done, but not for money.
Plastic straws are an easy target, because paper straws. Plastic straws have a compostable competitor that's functionally good enough. Plastic drink lids, not so much. | 29991ac3-31de-4420-ab07-5c47077db70e |
cc0pyl | the difference between shower gel and normal body soap. | Body wash, shower gel, liquid soap, etc. are all the same things. Any variations are purely cosmetic - they're intended to look, smell, or feel different, but they're functionally pretty much the same idea. The differences lie between any of them vs. bars of traditional soap.
Bars of soap are made from fat of some kind or another and lye, which creates surfactants (things that reduce the "grip" between different materials, letting the surface materials be washed away more easily). Body washes and shower gels are made from detergents - they're pretty much just diluted surfactants - but different ones than the ones that you get from mixing fat + lye. That difference causes body wash to have a lower pH than soap - closer to your skin's pH, in fact, which ends up with the body wash feeling more "moisturizing" versus the soap feeling like it's "drying your skin out". | 1b976e28-1267-4679-a32f-1ab3681a8876 |
cc12ez | How bugs (not referring to tiny ones) somehow get through screened windows with no noticeable entrances. | Info: are you talking like stuck between the screen and a closed window?
If so, many screens, while sealed into the screen frame itself, are able to be open and closed. They can run on a little track in the side of the window frame and can actually leave a small gap at the top (between the screen frame and window frame). While many bugs, like cockroaches, look huge, some can slide into places as thin as the thickness of a quarter. So even a small gap that you don’t notice or can’t see can be an exploitable entrance for bug kind. | ee8030c5-6e42-4bcc-a82d-7d576563d8d9 |
cc12uj | Why is there not a movement to ban junk mail that is equivalent to the movement that banned plastic straws? | Straws make up a very small portion of "how much waste" that is created. The reason that they're the first target of bans is because they're the easiest. Seeing at how much people freaked out over the tiniest, most trivial, "sacrifice", we're fucked. | 1315f9a2-2413-4594-9adf-0aca7689c795 |
cc1dzo | Why do you get better performance when playing a PC game in Windowed (Borderless) than you do in Fullscreen? | The only thing I can think of which would cause full screen to work worse than windows mode (borderless or otherwise) is because of:
* outdated drivers
* resolution outside optimal settings (such as resolution set too high or too low)
* v-sync and other anti aliasing settings too high or game graphic settings set to too demanding
* a program/app/window in the background is trying to gain focus while your game is running (such as an app set to "always on top" or some sort of overlay like steam, origin, uplay, twitch.
* you have a 2nd monitor and the frame rate/resolution do not match your primary monitor resolution
* you have a 2nd monitor and you have a video playing.
Edit
I though I was in a tech support subreddit for some reason.
Here is the ELI5:
Video game use a combination of either the CPU (the brain of your computer) and/or your graphics card to render ( or draw) what you see on your screen in the form of a single picture, called a frame. Your computer will process multiple frames per second to show you a smooth picture that has movement.
The more frames you have the smoother the image.
When you have multiple requests to your video card or CPU to render (or draw) images to your screen, you are using up resources that your computer has.
Generally the beefier your computer is the more resources you have. Such as more ram, better processing speeds etc.
When you run in full screen you are telling your pc not to draw the desktop and icons and instead draw the game you are playing. This mode gives your computer more resources it can use to give you more frames per second or better quality. However the higher the details/graphic settings for your game, the more your computer has to work to finish the rendering. If it gets to the point where it's taking too long to render the game at high settings the more lag you experience in the form of low frame count or frame drops.
There are some games that benefit from high frames such as first person shooters and other multiplayer games.
Generally you want to have lower graphic settings for these games so that you can have higher frames per second and thus see movement much faster and cleaerer.
On the other hand if you have a single player game that dosent require fast reactions, a higher graphic setting will give you a more vibrant and detailed environment at a lower fps ( frames per second ). | 9ee4e5d7-9a02-4b96-96db-1571b903ed36 |
cc1e9x | How to read classical song's title ? | Common abbreviations include:
*op.* - opus
*no.* - number
*mov.* - movement
Sometimes you’ll see a weird abbreviation at the end, like K. in Mozart or B.W.V. in Bach and those reference whoever cataloged the work. | f6ad3e55-2f00-4c5b-986e-b7c28aacf433 |
cc1fpv | why do 78% of Americans live paycheque to paycheck? | Wages are low, prices are high, and any progress you make can be wiped out in a day by an accident or illness. | c838267e-b18f-46ee-a5d8-119cb260a878 |
cc1fqz | What’s the difference between different sound file extensions like .mp3 vs. .wav? Is there any cost to converting from one to another? | In some cases, the extensions indicate the container types and not necessarily what is in them. Most times, like in the example case, the extension indicates the types of CODEC (file compression) was used to reduce the audio. The [MP3 uses MPEG1 (or 2) Audio Level 3](_URL_1_) but the [WAV is a container type that could house different audio types](_URL_0_). A good playback app will just read the header to determine what's inside.
Theoretically, you could have MP3 compressed audio in a WAV file.
That said, converting from one CODEC to the other is bad, m'kay. This is because during the compression phase, a good portion of the original data was thrown away, never to return. And each time you run a compressed audio file through a CODEC--even the same CODEC--you will lose additional data and the quality will be degraded [even more]. | e008e219-bfa4-4fca-b660-b5b88ebf0481 |
cc1luy | Why can't all plastics be recycled? | It's all about cost. If you have pristine poly-carbonate packaging from a pharma factory that's been handled by skilled workers in a super clean factory - sure, that's easy to recycle for what it will sell for.
On the other hand, if you've got a plastic straw from the rubbish bin of a McDonalds with smudge-proof lipstick on one side, molding sugary soft drink on the other side = > that's not so appealing. Plus, if it's mixed in with even-less-recyclable food waste, separating it will cost more than the end product is worth. It could be done, but not for money.
Plastic straws are an easy target, because paper straws. Plastic straws have a compostable competitor that's functionally good enough. Plastic grocery bags use a **very small amount of plastic** so they are not very valuable, and they have a lot of surface area to collect contaminants, like writing. | be5dfdc6-43e6-42ab-bc83-d367e03e7e27 |
cc1y08 | If blood is circulated only in veins, then why do you bleed of any part of your body is cut? | Because blood isn't moving just through the veins. There are other types of blood vessels, too.
The ones that reach every part of your body are called "capillaries", and they're basically really tiny blood vessels that are present pretty much everywhere in your body. Your veins and arteries are much larger, which is why you can see some of them through your skin.
Since the capillaries reach everywhere, you bleed from everywhere. | 018464cf-3ebd-4d6c-83b6-3b28e94edfd5 |
cc28f9 | How does an Anti-Thef system knows if an item's bar code was scanned or not, which makes it goes off(if the thing wasn't scanned)? I feel like there is something more than scanning some lines and *poof* no alarm | From what I know the thing that triggers the alarm gets destroyed by a strong magnetic field that is built into the cash desk. | 17d24480-253b-45fa-91f9-f2bb0925a9fe |
cc2bch | What is a bond? I'm looking into getting a peddlers license and it says theres a 2000 dollar bond, and I have no idea on what that is | A bond is, essentially, a check, that someone holds so that they can cash it if you owe them money and aren't able to pay.
Bonds are issued by a group called a surety. The surety puts the bond up for you, and you pay a premium to the surety. I'd guess the premium for a $2000 bond would be on the order of $100 or so - it's usually a pretty small percentage because the surety is assuming most of their bonds will never be cashed.
The point of the bond is that if you rip off one of your customers and you skip town, the city can cash the bond to pay back the customer. Or if you default on your sales taxes, or a few other possible reasons. | 25bf4c6e-532e-461e-a34a-9e1e83cf2549 |
cc3082 | What happens when our brains "zone out" | A special collection of brain regions becomes active to focus our attention inward - this collection is called the default mode network (DMN). Meanwhile, other brain areas, used to focus on things happening around you, become less active. The DMN has essentially taken over.
Source: I teach biopsychology and just covered the DMN today in class. | 28d39fef-aa83-4b71-b536-847e22425776 |
cc377e | How are we able to get such crisp pictures of astronomical objects, when the earth is constantly moving and destabilizing the image? | I mean while we're constantly moving (and at a pretty snappy pace), the objects we're photographing are so far away that relative to us they seem relatively static over short time periods - just like when you're in the car driving and the Moon seems to stay in the same place in the sky no matter how fast the car goes.
Plus a lot of the more incredible images are space telescopes, and so the actual rotation of the Earth isn't a factor, just it's orbit. | 7333f273-9e0e-4193-80df-91c58c894598 |
cc37dj | Crude oil is black, but gasoline is clear. What is the black stuff, and where does it go during the refining process? | Crude oil depending on where in the world it was extracted, is anywhere from a dark brown, to an almost golden color.
_URL_0_
The darker the color, generally the thicker it is, and the more sulfur it has. Light sweet is just that, light in color and apparently tastes sweet. Thicker and sour crude oil has more sulfur and apparently tastes sour.
When oil is refined, depending on what oil they started with, and what the refinery prefers to make during the distillation and cracking, they'll get different stuff.
Bunker oil and asphalt/bitumen/tar is pretty much the left over sludge that's a very thick and dark in color. Bunker oil is used to power large cargo ships. Various lubricants and greases are also made from the thicker darker stuff.
Gasoline for a long time was the "waste" from making kerosene which was used to light oil lamps, it's a very light distillate, and thus more light honey-bluish in color. | 2cf8ac8b-6df1-44b2-8b8e-92842917e512 |
cc3a9m | Is perfect pitch cultural? | There are indications that culture contributes, yes. That is, there is evidence that most people can *learn* perfect pitch but most do not.
The usual comparison is to frequencies of light, which everyone sees as their absolute value. Red is always red, regardless of whether it's next to green or blue or anything else. Sure, our eyes and brain compensate for lighting and other conditions, but for the most part you're looking to know what the color is, not its relation to other colors around it.
The opposite is true of sound. We care more about the pitch relative to pitches around it. If you pitch shift a song up or down it's still very recognizable as that same song. Most people can't discern exactly what pitch they're listening, although most people *can* tell you if a pitch is higher or lower than the one before it.
But the presence of people who have perfect pitch suggests that our brains are perfectly capable of discerning absolute pitch, they just choose not to. They're discarding that information in favor of its relation to pitches around it. Why? Because absolute pitch largely doesn't *mean* anything. Relative pitch *does*. A person with a bass or tenor speaking voice isn't angry or upset when they speak normally. A person who speaks in roughly an alto range who suddenly shifts to a tenor *is* angry or upset. Someone with a soprano voice isn't perpetually excited, but someone shifting up into soprano is. So is someone shifting from bass to tenor, even though the alto shifting *down* to tenor is probably upset or angry. So the fact that it's a tenor voice doesn't mean anything unless it's in the context of their normal voice changing.
So our brains learn very quickly as we acquire language that relative pitch matters and absolute pitch doesn't. There is no *grammatical* difference between a word said in a high pitch or that same word said in a low pitch. It means the same whether Andre the Giant says it or Alvin the Chipmunk says it. Pitch only changes the *affect* of the speech, not grammar, and only relative pitch. Even when we learn music, relative pitch still matters more. You don't *need* perfect pitch to be able to play or write music, it just helps.
However, there are cultures in which absolute pitch definitely does matter. In tonal languages, the pitch of the word *does* change the grammar. The exact same mouth shape, the same vowels and consonants spoken together will mean different things if said in a different pitch. They don't just convey emotion, they can completely change the definition of a word, the same way that adding or removing a letter in English completely changes a word (for instance: "word" vs "sword"). In cultures with tonal languages, people with perfect pitch appear to be more common. This makes sense: instead of discarding the information about pitch, the brain kind of needs that information. It's still not as important as relative pitch, but it's a *little* more important than it otherwise would be. As a result, they are more likely to *learn* to hear pitch as absolute instead of only relative. | 06fd45f6-44ac-4514-95ca-3dceb81b607b |
cc3iu1 | How do dryer sheets work? | Dryer sheets are used to counteract the static charge that builds up from the friction of the clothes and the dryer.
When you shuffle your feet on a carpet and then touch a doorknob, you might generate a little static electricity and get a shock. It has to do with electrons shifting around in the different materials.
But if you rubbed a little oil on your shoes before shuffling on the carpet, the oil would essentially prevent the transfer of a bunch of those electrons, and you wouldn't get shocked. It has to do with the non-polarity of the oil.
Dryer sheets contain chemicals that prevent the electron transfer.
Check this out:
_URL_0_ | 0dfe5c5a-090d-45bc-ac96-f8b6ed6af8ce |
cc3n4b | Why is it useful to understand the Greek idea that Gods are a personification of human emotions, personality, etc? | It would depend on your definition of “useful.” It might be helpful in understanding the mentality of people from times past. It would certainly be important in understanding the history of religion, or possibly cultural history. I’ll also add that the way you worded the question makes it seem like you were told it’s important and aren’t sure why. In that case, perhaps ask the person who told you - it may be important for a particular reason to a particular person | ce9b6ba0-6ec0-4a5c-9327-3e0a1c5bf1a7 |
cc3tyo | Can someone explain mortgage points to me? It’s just not clicking for me. | They're a bit tough to wrap your head around. As best as I can explain it, "points" on your mortgage is an offer to allow you to pay some extra money to the bank in order to lower your interest rate by a specific amount. Usually it's 1% of the loan amount per point, and a point will lower the interest rate by 0.25%. The end result is that you pay a little less in each monthly payment.
For example, a $200,000 mortgage at 4.5% will run you \~$1,013/month. But if you can afford an additional $2,000 up front, you can buy a point, and the interest rate will be 4.25% or \~$984/month, a $29/month savings. As long as you're going to keep the mortgage for long enough for your total savings to exceed the amount you paid for the points, it becomes a worthwhile investment. In the example, thats ($2,000/$29 per month \~69 months, or 5 years, 9 months). So the additional $2000 will save you more than it costs as long as you keep that mortgage for that long.
There are additional things to consider when trying to figure out if points make sense for you, from paying extra principal each month also/instead, to tax implications (though with the latest tax cuts, I'm not sure if those exist anymore), to the opportunity cost of spending that $2000 up front rather than investing it or keeping it as an emergency fund. I'd advise learning how to set up a spreadsheet with formulas for different options and running the numbers in each case to see what ends up saving the most money (especially in total interest paid) and/or keeping the most money available for use.
& #x200B;
FWIW, I have never bought points on any of the mortgages I've taken, preferring instead to pay a little extra principal each month and maintain a slightly larger emergency fund. Of course, most of that was back when the mortgage interest paid tax deduction was available to me. | 84c0c0c5-ae4e-433a-a120-e1b02ebcd948 |
cc4793 | How does _URL_0_ work? I find it is very accurate; the thunder projection is almost always spot on, but i don't get how they can detect lightning. | There are lots of antennas that are registered with _URL_0_
Those antennas detect lightning by means of picking up their electromagnetic waves they create when lightning occurs. If you get an AM radio, you can do the same by tuning it to the lowest frequency and listen for the static that happens when lightning strikes. Each of these antennas have their location known by GPS, so each antenna that detects a strike reports the strike and the system knows the gos location of each antenna and triangulates the strike and displays it on the map. | d7e57729-98ce-43ac-808d-0fb2581257a2 |
cc4cux | Is it true that baling wet hay after a frost won't start on fire vs baling wet hay after rain will? If so, what makes the difference? | The percentage of water moisture in the hay.
Frost is very little actual water and just on the top whereas a typical rain will wet all the hay.
The amount of water determines if the hay dries (no problem) or if there is enough moisture that the hay will begin to decompose (problem). The decomposition is what creates the heat. Enough heat and the bale catches on fire. | 9c704243-a79d-4a07-88fa-15dc6b6bf770 |
cc4dzb | How is only the music score removed from a film for when orchestras play live along with the movie? | Movies have multiple sound files that can be changed while still watching the same video file. They are seperate.
For example, many DVD's have an option to play either the English version or a version that's in another language such as Spanish. You can toggle between these two different audio tracks while watching the movie.
For Jaws they would have simply removed the audio tracks with the music.
Edit: oh and this has been common practice for a while. Even movies before being digital would have different audio tracks. | d3736df4-8e70-42ee-95fe-306188825082 |
cc4l85 | why are plastic bottles such a hot topic for pollution but glass bottles are never mentioned? Is glass better for the environment? | Glass is super easy to recycle, and 100% of the material can be recycled. You just have to break it up, heat it up, and reshape it. You can throw beer bottles in with milk bottles in with window panes and all sorts of other glasses together, and it's not a problem at all. It's all the same glass. And you can recycle it over and over and over again, never losing material, and never having to use new material. We could recycle it hundreds of times and never need new stuff. AND the energy we save in recycling them, compared to making new glass, is enough to power a 60 watt light bulb for four hours. That may not seem like a lot, but it does mean it's actually CHEAPER to recycle glass than it is to make new glass.
There are a ton of different kinds of plastics. They all have different methods of recycling, so your plastic bottle with a plastic lid and a plastic retaining ring need to be separated, shipped to different recycling plants, and then only a portion of that plastic can be recycled. It's a polymer material, so it's made of lots of different compounds (oil being one of them!). These different materials may not even be recyclable with current technology. So we have to keep adding these different materials, and that drives up the cost significantly. It's more expensive to recycle plastic than it is to make new plastic. | 321e26d7-d704-40ac-be9d-97504c1781b9 |
cc4nbv | How do observations of early history of universe work? Most of the times it is mentioned that light emitted 10-13 billion years ago is being observed. But doesn't it fly against the 'big bang' theory? | One part of the Big Bang Theory is Expansion.
Early after the explosion of matter, spacetime unfolded rapidly, because it was no longer being warped by all of the matter sitting in one place.
That spacetime didn't just unfold around the freshly exploded matter, it unfolded in between stars and gas clouds.
This essentially added space in between groups of matter, and effectively sped them up beyond the speed of light.
This allows for matter to be more than 14B light-years away from the center, even though there wasn't enough time for it, and allows observers on Earth to see objects as they were billions of years ago, and sometimes 80B light-years away, even though only 14B years have passed. | 470f44ff-6e8f-4d7f-a628-09120ad7cebc |
cc4qmk | Why does food that’s hot taste so different to the same thing cold? | Answer. Taste is a combination of your sense of smell and your taste buds. For example, if you are blindfolded and hold your nose, you cannot tell the difference between bbq sauce and ketchup.
When food is hot, there is more of a smell that comes off of it. Pizza being a good example, the meat, cheese and sauce let's us a unique smell that combines with the taste buds to tell you what it taste like.
When food is cold, it does not release as much of the smell. A hot pizza smell will fill a room. Cold pizza wont. | 006a5b04-c51e-4af7-905c-7f653fc56e69 |
cc4r0l | what are flies doing when they buzz around you but dont land? | Flying around because it’s fun as hell. Looking for food. Looking for fly coochie. Trying to avoid spiders. I spent a summer as a fly in France. It was pretty neat. Wouldn’t want to do it again though. | eea93688-28cb-482c-88ff-643dc40495bb |
cc4rt6 | Inspired by recent meme on r/steam, How does verifying the cache of a steam game (TF2, CS:GO, etc) solve so many problems that could be lengthy fixes? | To explore what cache verification does, it's important to be passingly familiar with a particular concept in computer science: that of the *checksum.*
A file's checksum, briefly, is a small piece of data that a computer can create by looking at the ones and zeroes that make it up. A checksum, then, is sort of like a fingerprint. Each file (theoretically) has an individual, unique checksum, and altering a file even slightly produces a different value.
Why is this important? Well, what cache verification does is instruct Steam to take checksums of every file in your game directory and compare them to the checksums in Steam's servers. If there are any differences, that means that a file you have doesn't match what Steam says you should have, and so your client will replace it with a known good copy from Steam's servers. | 7f571001-2f2d-45c1-a1f3-3e315bde7b64 |
cc4sc1 | Why do larger species of fish have darker meat than smaller species of fish? | White meat = fast twitch muscles which are used for short bursts of energy.
Dark meat = slow twitch muscles which have myoglobin (that’s why it’s dark) and are used for sustained swimming, long periods of activity.
Most small fish only use short bursts of energy, whereas larger fish are swimming for longer periods of time | 715c8922-965f-4f90-8606-ff09698a4f20 |
cc4vhh | How do astronauts shower? | Astronauts on the ISS don't actually shower like we do on Earth with running water. They basically take towel bathes. They use liquid soap and a little water on the skin, scrub with a towel, and then wipe once more with a wet towel to "rinse". For hair, they use rinseless shampoo and a little water, and use either a towel or their hands to massage it in. [Here's a video of astronaut Karen Nyberg washing her hair on the space station](_URL_0_).
Skylab, The U.S. space station from 1973-1975, had a zero-g shower similar to what you'd use here on Earth, but it wasn't very efficient in terms of both the amount of water used and the time it took to use it, so they abandoned the idea for the ISS. | cf693efe-05f6-46c3-b9b3-4b8d3600cfe7 |
cc4wan | What is the “black web?” How is it different from the regular web and how do you access it? Does it look different? | Deep web is a term for any World Wide Web content not indexed by search engines. That could mean dangerous or illegal sites with random URLs (or none, only accessible by IP address) that have chosen to hide themselves from search engines and most users. But it could just as easily by people's personal web servers, sensitive government stuff, corporate employee portals, online banking, services requiring paid subscriptions etc.
Dark web is a term for a web-like network that exists on the internet, but is not accessible via normal web browsing. The biggest example is the Tor network. It's usually encrypted and requires special software or authorisation to access. It *can* be totally legitimate content/services that people want to keep secure; for their personal use, within a trusted group, or just generally from malicious governments or other authorities. But a lot of the time it means hiding illegal activity from law enforcement and ensuring anonymity. Besides the fact that it's typically encrypted, anonymous and hosts a lot of illegal stuff, it's otherwise the same as the regular web and uses HTML, web browsers, servers etc.
"Black web" is not a term I've heard, presumably it's the same as dark web. | 6211f425-2300-470a-9d0d-4a01bae2124c |
cc4xwp | What is a sourcecode? | The "source code" of a program or application is just what it sounds like: the original code that a programmer wrote to create the program or application. | b77fdf8a-c07f-439b-ac09-facf8cac11f7 |
cc56y3 | How do blankets and other objects keep us warm? How do they produce heat? | They don’t produce heat. But your body produces tons of heat and the blanket keeps it close to your body rather than letting it disperse into the air.
Electric blankets do produce heat. But that’s different. | 9006687e-6fb8-4204-abe4-b34b9c59609b |
cc58hv | How can bugs crawl on the ceiling? I understand they might have really good grip, but does the blood not rush to their head? | Bugs do not have a circulatory system that works the same as ours at all. They really only have a heart and a single aorta going from the back end to the front and then their "blood" just circulates freely through them amongst the other organs back to the rear to be pulled in by the heart again. But that's not the main thing...
Because we walk upright our circulatory system is optimised for needing higher pressure to get blood back from the feet and legs to the heart and much lower to get blood back from the head to the heart. When we are upside down blood pressure increases in the head becuase we are the wrong way around.
Most bugs though walk with their heads on the same level as their heart anyway so when they are upside down it makes no real difference since the head is still at the same level as the heart. | c0fc2efd-1bf4-4cf8-b177-91812e6b73fb |
cc58mf | The saying goes “never add water to acid”. How come your stomach acid does not react when you drink water? | You don't want to add water to acid because some strong acids can react violently to the water, heating it quickly and causing it to boil, splashing acid out of the container. In the stomach there is both no danger of the acid splashing out, and also the acid employed in the stomach simply isn't that strong so there is no danger of that level of reaction. | 84f707e5-6cb5-4bb0-be72-3903dbff7262 |
cc5gcn | Price Elasticity | The "Price elasticity of Good X with respect to Y" is the percentage change in Y induced by a 1% increase in the price of Good X.
To make a more concrete example, suppose that X is hamburgers and Y is demand for hamburgers. The current price of hamburgers is $1, and 1,000 people are willing to buy a hamburger at that price. Imagine raising the price to $1.01. This higher price may drive away buyers, specifically people who were willing to buy at $1 but not at $1.01. But how big will the response be? That's what elasticity is for.
Suppose the new demand for hamburgers is 995 people. Then the price elasticity of demand for hamburgers is 0.5. Economists would say that this is an "inelastic" response. In percentage terms, the demand for hamburgers fell LESS than the increase in the price. Money spent on hamburgers went up (from $1,000 to 1,004.95).
We could instead observe that the new demand for hamburgers is 985 people. Then the price elasticity of demand for hamburgers is 1.5. Economists would say that this is an "elastic" response. In percentage terms, the demand for hamburgers fell MORE than the increase in the price. Money spent on hamburgers went down (from $1,000 to $994.85). | 613f0d40-5fa2-4300-aae0-9a0d565373bb |
cc5ibd | How is the Gold Standard a fiat currency, and how does Gold Standard currency go through inflation? | The gold standard can be thought of as a fiat currency because, like a normal fiat currency, gold only has value because we say it does. Gold has no more intrinsic value than aluminum (under Napoleon, aluminum was more valuable than gold) | 49aff66e-1af3-4a76-9e6a-7c0918b8b8bd |
cc5u61 | why is it that some features (like a GPS) are bought once while others (like in car wifi) need subscriptions, when they both use satellites? | GPS is operated by the government. WiFi needs a internet provider which needs money to maintain the network. | bfb9106b-f9d2-4f95-b400-aeaab5f0e6f1 |
cc5yoh | What causes animals to die of old age? | The cells in your body are constantly replicating themselves and then dying off. Your hair and nails are made of these dead cells (and that's why your hair and nails grow).
However, every time a cell replicates, it's not exactly perfect. There's a piece of the cell that acts almost like a timer. Every time the cell replicates, that timer piece gets a tiny, tiny bit shorter.
Have you ever photocopied something? You know that the photocopy isn't quite the same? There's always a slight be a degradation.
Well, that's what happens with a cell. So eventually, the degradation becomes so bad that the cell can't perform it's function correctly. That's why we get symptoms of old age as well.
Then eventually, the replicated cells just start to fail and that eventually leads to death. | bdc3d42b-ff72-4160-8e73-164e40bf5194 |
cc63az | How come Google-translate is so bad when everything else google does works so well? | It’s absurdly good, machine translation was thought of as impossible magic that would never get even this good. Language translation requires a deep understanding of two or more languages in a way a machines are normally totally without. | 0e94848b-a54d-4f83-9e11-7e9a5f723ed4 |
cc674h | Octonions - what exactly are they? | The complex numbers are a sort of two-dimensional extension of the real number line, with an imaginary axis (i, 2i, 3i, ...) along with the ordinary real axis (1, 2, 3, ...). It turns out that you can extend this idea even farther to have four distinct axes ("quaternions"), or eight ("octonions"), or sixteen ("sedenions"), and so on for any power of 2. While a real number might just look like 3, and a complex number might look like 3+2i, a quaternion could look like 3+2i+4j+6k, where i, j, and k are distinct values with the property that i^2 = j^2 = k^2 = -1. Octonions would then have eight distinct components, one "real" component and seven distinct "imaginary" components.
The farther you go with this, the more nice properties about numbers you lose. When you go from the real numbers to the complex numbers, you lose the fact that numbers have a neat linear ordering. When you move from the complex numbers to the quaternions, you lose the fact that multiplication is commutative: for quaternions, it need not be the case that x\*y = y\*x. When you move from the quaternions to the octonions, you lose the fact that multiplication is associative: for octonions you aren't even guaranteed to have x\*(y\*z) = (x\*y)\*z.
Despite the fact that the octonions are both rather abstract and lack many of the properties we expect number systems to have, they show up occasionally in theoretical physics. | 2580c158-d679-4fff-8094-4049ac8d6bfc |
cc689k | If a neutrino is hypothetically stopped and observed, how could the flavour be determined? | The way you pose the question is a bit confusing so I'll clarify that oscillation refers to the probability of measuring the neutrino to be a certain flavour. It happens no matter what speed the neutrino is moving. If it didn't, that would be a violation of special relativity.
The problem with a neutrino at rest is you can only measure flavour by producing a charged lepton via charged-current scattering. There needs to be enough energy to create any of the leptons. You could try to do this by firing a proton beam at your stopped neutrino, but any scattering products will be at a very small angle to the beam and probably not measurable. | 86d4f19c-30ee-4326-aa91-8b70b0790d9d |
cc6e8b | How do places like Churches or MacDonald's avoid losing internet over illegal download copyright strikes from ISP's due to random folks who use their net? | I had no idea that churches had wifi.
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But any big company will have a specific type of networking that disallows connection until a browser is opened to a specific webpage(usually it will open if you are connected and haven't been there yet) that is a ToS saying "We are not responsible for dumb shit and will comply with any legal investigation" before it allows you to connect.
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Smaller open wifi networks are not protected by this, even with a password protection. There is a possibility they may be held accountable for illegal activity. However, there are general laws, which protect sites like Reddit too, that say that the provider is generally not liable for what it's users do. | a8883dd1-49ac-4619-bd99-f229099ba61b |
cc6fd6 | My modem is experiencing “T3 timeouts” and the condo building I live in is “noisy” as far as my connection goes. Why is this causing disconnects from game servers? | a T3 timeout is your modem saying "screw this, I can't keep my connection stable. Maybe if I reconnect and renegotiate I'll get a better connection". When that happens, the modem has no connection between it and the cable head end and thus no internet connection.
I'd complain to building management or whoever is in charge of the internet. You're paying for the service somewhere, you need to bitch until you get it. | 4a55ff5d-585f-4381-b5e6-acd8d42df5c1 |
cc6msr | Is "yawning because of boredom" a cultural thing that is (unintentionally) taught to us or is it natural? And why? | As far as i know, yawning has the intention of causing to awaken you to some degree.
It causes a lot of your muscles to tense/activate and the big breather you do is meant to get more oxygen into your system.
I could imagine due to your inactivity when bored, your body is thinking that you're tired, or your body wants to keep you more active. | c4669983-8a43-4509-b751-f56f694a7015 |
cc6p8q | Plato’s Tripartite Soul | Hi! This might not be very ELI5-ish because philosophy is pretty hard to explain to 5 year olds, but I hope this helps!
Socrates claims that since the soul has opposing features, the soul must be divided into parts: appetite (physical desires) , spirit (anger), and reason (logic lol). Socrates explains to Glaucon that, “It is obvious that the same thing will not be willing to do or undergo opposites in the same part of itself, in relation to the same thing, at the same time.” (436 c) By saying this, Socrates is applying the law of noncontradiction. This law states that the statements ‘A is F’ and ‘A is not F’ cannot be true at the same time, since they contradict each other. However, Socrates brings up an example which implies that ‘A is F’ and ‘A is not F’ can be true at the same time if ‘A’ refers to different parts of an item. For example, Socrates talks about a spinning top saying, “...whole spinning tops stand still and move at the same time…” (436 d). In most cases, it's pretty normal to say that standing still and moving are two opposing actions– you can't really move and be still at the same time– yet, in this case, we can say that while the top is moving (A is F) because it is spinning, it is also not moving (A is not F) because it is staying in place. The ‘A’ in this case refers to two different things: moving by spinning and moving by going along a path or in a certain direction.
To understand how the soul is divided into parts, Socrates explains how appetite, reason , and spirit oppose each other. Socrates begins by using an example of a person that is both impelled to drink, but is also impelled not to drink. This example explains how the appetite and reason conflict with each other. Socrates reasons that, “...what drives and drags them to drink is a result of feelings and diseases” (439 d). The appetitive part in this situation is the person wanting to drink because they are thirsty. What makes this thirsty feeling appetitive and not something else is because this feeling is derived from the bodily senses. On the contrary, the logical part, also known as reason, doesn't want to drink because they are ill with a disease that worsens the illness if they drink. (Which you can't really understand from the book unless you have good footnotes/professor that explains this part. I can't really remember details but basically people back in the day used to think that drinking when you're sick would make you worse or something along those lines.)
Socrates then explains how spirit comes into conflict with the appetite. Socrates uses the example of Leontius and the corpses, to which he says, “He had an appetite to look at them but at the same time he was disgusted and turned away.” (440 a) In this case, Leontius is both impelled to look at the corpses and impelled not to look. The appetitive part of Leontius wants to look because he finds beauty from looking at their pale faces. (Not so fun fact: he was aroused by how pale young boys looked when they were dead) On the other hand, the spirited part of Leontius is impelled not to look because he gets angry with himself, since it is unjust to take pleasure in looking at corpses.
Although Socrates states in the beginning that parts of the soul can be found by looking for opposition or psychological conflict, he does not have a good example of how spirit and reason oppose each other because spirit and reason are natural allies with one another. However, in this case, Socrates is able to explain that spirit and reason are separate parts because they can appear without each other in certain circumstances. Socrates says that,“Even in small children, one can see that they are full of spirit right from birth, while as far as rational calculation is concerned, some never seem to get a share of it, while the majority do so quite late.” (441 b) What Socrates means by this statement is that children are born with spirit but lack reason until they are more mature. which demonstrates how spirit exists in a being even when the being is without reason.
TL;DR: Basically, Socrates split the soul into three parts because the three parts (that he decided makes up how human beings work) either contradict (apettite vs reason/appetite vs spirit) or just exist on their own (spirit). | 196afe97-4d9a-4e6b-8d9b-96e7889b3e09 |
cc6q4e | How does an airplane (especially passanger ones) fly. | So. The first thing required is speed, but not for speed’s sake. There isn’t an arbitrary ‘flight’ speed. The plane must accelerate by some means (prop, jet, rocket) to sufficient speed where the air being forced over the control surfaces generates enough ‘lift’ to overcome the weight of the plane. Lift is generated by the design of the wings, which force air “Down” which lifts the plane up, the inverse of how race cars are designed to force air “up” and push the car down to create grip.
Once the plane is in the air, the pilot can move the control surfaces to determine where the air should be forced, and thus what pitch the plane will fly at. The control surfaces can also be moved independently to achieve Asymetrical lift, making the plane roll (Those are called ailerons).
However once at speed, a plane can only go so fast before resistance from the very air that lifts it prevents further acceleration, just like a car.
And unless specifically designed to handle high pressure, like fighter jet, a plane going too fast and pulling maneuverers can rip it’s own wings off as the construction cannot handle the pressures of the air pulling at the airframe, this doesn’t happen often these days.
As for staying high for long periods at speed, this is achieved because the air at high altitude is thinner than low, which results in less drag for planes which can reach those heights, like passengers jets. That reduced drag means the plane can both go faster, and use less fuel. This is known as ‘cruising altitude’ and it is the most efficient altitude for a given plane based on it’s engine power and fuel consumption.
For example a prop aircraft like an old B17 has a much lower cruising altitude than a modern 747 because it’s combustion engines could not function well that high up, as they require more oxygen than a jet engine. | 5553f043-d7bf-42e5-aba1-6db9860a0aa6 |
cc6sbf | - Why does asking someone to help us choose between things help us to solidify our answer, even if it is not the choice that the other person suggested? | You're probably already leaning toward one answer. If they agree with you, it reaffirms that you made the right choice. If they disagree with you, but you disagree with their reasoning, that can again reaffirm you made the right choice. If they disagree with you, and manage to convince you of their reasoning, your choice has changed **and** someone agrees with you, so that's basically the same as if you agreed initially. | 5bac3445-4864-4148-97d6-489b356f7b95 |
cc6wdi | Why do some animal's horns (such as rams) grow long enough to get pierce right in the face? | "Nature" isn't an intelligent entity. The ram's horns grow in such a way that normally they don't become a problem, or at least don't prevent the ram from breeding. But if it does then that ram's genes don't reach the next generation and the result will be fewer rams which have their horns grow in such a way. | 92d69fdf-291b-4199-8745-41949b843edc |
cc6yde | Why does one violin sound raspy but multiple violins sound soft? | It has to do with the sound and the way it moves. If you get one, you hear all the imperfections. If you get a group, the sound molds together so all the little imperfections get drowned out and you just hear a single note as opposed to scratches everywhere | 1ff9434b-e921-46df-96af-6912669e73c2 |
cc73co | why is there an alligator loose in Chicago? | Because people are idiots.
More than likely, someone thought the idea of a croc was cool, got themselves a baby and, when it grew up and got big, they dumped it. | 20683edd-330d-4916-863c-f2380bbe1e12 |
cc78oc | Why do some food and drink products state on the back to eat or drink it within one week or one month of opening? | the inside of the bottle is sterile when it's sealed at the factory, and opening it exposes the inside to the bacteria in your home. If the food is suitable for growing bacteria, it will go bad soon after the bacteria is introduced, but would be fine if the bacteria were never introduced in the first place.
This is the same reason a lot of foods say to refrigerate after opening - they can grow bacteria at room temperature, but before they've been opened, there's no bacteria in there to grow. | e534a6de-c1f4-455b-89ae-aa646d6a002a |
cc7eie | Are there any restrictions on the world’s richest people and how they could spend their money? For instance are they allowed to just buy out an entire city companies and just fire everyone for the sake of causing chaos in the economy? | It depends on where you live and where you plan to use your money that way.
Some countries have more laws than other about what people are allowed to do with their own money.
Many countries have laws that in theory should prevent people from creating a monopoly or acting in ways that negatively affect society as a whole. Enforcing such rules on people who can afford the best lawyers and officials that money can buy can be difficult.
For example Article 14 of the German Basic Law (constitution) says that "Property entails obligations" an idea somewhere between Peter Parker's "with great power comes great responsibility" and the classic "Noblesse oblige". Of course trying to make a case for this is not easy, but with a case like you suggest it should be possible. | 288d14b8-5946-4a13-a7c5-0c007ce7bd4b |
cc7g09 | The differences between method and methodology | Comic response: Undergraduates who want to sound more intelligent say 'methodology' rather than 'method'
Correct response: A method described the apparatus, procedure, etc. of a single study. A methodology is an established set of apparatus, procedures, etc. that are regularly used in similar studies. | f601828e-d41e-467c-a51c-991915d57d17 |
cc7o4k | If seemingly nobody agrees with the current drinking age of alcohol being 21 in the USA, why is it still illegal and taboo? | It's a cultural thing. America had a strong temperance movement wich lead to the prohibition. This was later removed again but drinking was still seen as problematic by many so they made this strict age limit.
If really a majority was for a reduced drinking age, and would be loud about it, it would get changed. I imagine if politicians tried to the outrage by "protect our children" activists would be stronger than any current movements for reducing the age (are there even any?)
Same why cannabis isn't widely legalized even though experts agree that it's not more dangerous than alcohol for adults. | 1e1fe415-41fb-42d3-898d-9a01b9ce2b3a |
cc7tkc | Why is Pi irrational? What is it about the properties of a circle that causes its circumference to never be a precise ratio of its diameter? | Here's another way to look at it. Rational numbers are ones that end with an infinite series of zeros (2.4000000...), or an infinite series of repetitions (0.1428571428571428571̅4̅2̅8̅5̅7̅.....). Now, what is the chance that any value, chosen at random, would end in an infinite pattern?
Effectively zero.
So you would expect that rational numbers would be the rare and unusual ones. And that is what we find. Pretty much any mathematical constant - like Pi, e, phi and the square roots of every single non-square whole number, are irrational.
So Pi being irrational is nothing special. Indeed, it would be really, really strange if it wasn't. | 3da68097-41ad-469f-821a-e6338274177d |
cc7z28 | Why is it sometimes very difficult to clench your fists in the morning? | When you’re sleeping your body makes it so your muscles don’t move. So when you dream you don’t flail around irl. When you wake up your body is transition back into freely moving and it can take a minute to recover. | 28c09271-6f59-44b1-8bad-0f3dfa35a04b |
cc8gzn | How does the DMAS (divide first then multiply then add then subtract) hold true in real word physics and situations? | This choice has no effect on the real world. It just allows people to communicate mathematics to each other unambiguously.
It's a bit like wondering if the order of the alphabet is important. Well no, not really. | 5a9dbce6-9e22-4bbc-ac72-3a476d5f4d15 |
cc9cge | Why were animals so much bigger in the ancient past? | [_URL_0_](_URL_0_) according to this we had bigger insects because of a higher oxygen concentration. they actually had to to avoid oxygen poisoning. | f71930d9-2238-45e4-b5c4-a0495c748116 |
ccadw7 | When and why did humans take up meat in their diet if a plant life is sustainable? | As near as we can tell, human started eating meat regularly long before we became modern humans, and sometime after our ancestors evolved an upright gait. This made us more efficient runners, and allowed us to hunt animals by chasing them until they were exhausted and could no longer run or effectively fight. At that point we would stab them with pointy sticks.
At the time, sustainability was a complete non-issue for us. We did not yet have the language necessary to form thoughts necessary to understand the concept. | f4ed85d4-7e7b-48b4-bca2-e0527df78211 |
ccan9b | Do baby hairs on our hairlines grow to full length if we let it grow? And why do they exist? | No, they don't! The simple explanation is this:
In one hair follicle, the hair grows in "phases". In Phase 1, you have new cells attaching to the end of the hair (at the base/root) and pushing out, "growing" the hair. In Phase 2, new cells stop attaching and you basically have a 'dead' hair follicle - your hair won't grow any longer.
In Phase 3, NEW cells start forming a NEW hair right underneath that last hair, and eventually push it out completely - now you have one long hair that fell out, and a new *tiny* hair that's growing in its place.
& #x200B;
Every type of hair has different lengths of time for this cycle - this is why your head hair can be three feet long, but you never end up with 10" long eyebrow hairs or arm hairs. It's mostly related to genetics, but in general head hair cycles are a lot longer, while those "baby hairs" are shorter life cycles.
& #x200B;
As an extra piece of information - each follicle is on its own clock, which would be good - otherwise, once every 6 months, all your eyebrows would fall out at the same time and you'd have to wait for them to regrow again. | ea40b9fb-5725-476e-bdac-0c08a719ab68 |
ccaqvz | Why is signal strength halved/doubled for every 3 dB of attenuation? | This is a dimensionless measure of power/intensity. It is a ratio of a signal level (power typically) to a reference level. It is a logarithmic scale. A decibel is one tenth of a bel. A difference of 1 bel means a ratio of 10:1. So a measure of 0 dB means the signal is at the reference level. 10db = 1 bel is 10 times larger than reference, 20 db is 100 times larger, 30 db is 1000 times larger and so on. So a measure of 60 dB is 1 million times larger than reference.
Since the square root of 10 is approx 3, therefore 3 db increase is approximately represents a doubling of the measured signal (using properties of logs and exponents).
You can convert the ratio to an actual signal level as long as you know the reference (or 0db) level. It is 10\^(db/10) \* reference level. | 9795c50e-21a3-402a-9150-d442b7ff5479 |
ccaven | What exactly is mental stamina and how does it work? | It's also called "mental toughness". It's the ability to carry on doing something difficult or painful, when you feel you are out of strength. It's pushing through the mental or physical pain. To endure it and come out the other side feeling stronger and better. It's to not give up in the face of adversity. The military is great at giving people mental stamina. Teaching people they are way more capable than they think they are. Watch the following show and you will learn about mental stamina and who has it and how it works.
_URL_0_ | 0698a3dc-0844-4f43-a1a2-85d04dcc7bd8 |
ccb133 | What happens when our body parts “fall asleep”? | It's due mostly to nerves, not loss of blood.
> We've got nerves running through our bodies that act as lines of communication between the brain and the other body parts, transmitting commands from the brain and relaying sensory information back to it for processing. With a "sleeping" limb, your nerves are going a little haywire because prolonged pressure has actually cut off communication between that limb and the brain. (The tingling sensation is technically called paresthesia.)
_URL_0_ | 7884d01c-daea-4a37-99e1-60d175d4846e |
ccb29h | Why is the driver's seat on a north american boat on the right side? | Because the "right of way" rules for boats are international, and they are "yield to other boats on your right". So sitting on the right gives you a better view to make sure you avoid a collision when it's your responsibility to turn to avoid one. | bf098ba9-a08f-4176-9a5b-0b15c4fa8b83 |
ccb5yf | Why do ulcers in my mouth taste metallic? | If i had to guess, it would be the blood coming from the ulcer, even if in small amounts/not actively bleeding. Blood tastes metallic due to iron content | b1953b8f-6a66-4751-8d60-b550e95226f1 |
ccbbc9 | Why is everyone blaming the "boomers" for today's economy? | To add to what others had said, they created a tax policy that incentivized outsourcing jobs and paying workers as little as possible while shifting as much of the money and profits as possible to the already-wealthy investors.
They decreased the funding for government research & development that helped the US be a tech leader in the 50s and 60s while cutting their own taxes and driving up the national debt.
They focused on making themselves as wealthy as possible at the cost of the environment while pushing the debt and cleanup costs to the next generation. Privatized profits and socialized debt.
Edit: I want to add that this is not a problem of the past. The Trump tax cuts tripled the deficit, adding trillions to the national debt while almost all of the benefits are going to the already wealthy boomers that are now in their 60s, 70s, and 80s. | b8a9f556-bea3-47b3-ae81-006597307e34 |
ccbca5 | In the UK, under the equality act 2010, you cant discriminate someone when they apply for a job under protected characteristics, so example, if someone has no arms and applies for a office job and dont get it can they sue for discrimination even if they physically cant do the job ( because no arms) | No.
For one thing, there may be ways in which a person with no arms can actually do an office job, with prostheses, or voice-control, or what have you.
But leaving that aside, the law does not allow people to sue for discrimination when they are rejected for a job they can't do. The law states:
& #x200B;
\ > A person (A) discriminates against a disabled person (B) if—
\ > (a)A treats B unfavourably because of something arising in consequence of B's disability, and
\ > (b)A cannot show that the treatment is a proportionate means of achieving a legitimate aim.
& #x200B;
The ability to do the job is a 'legitimate aim,' so the hypothetical armless person, if unable to do the job applied for because of that disability, would lose the case. | c50d5c34-fde3-492c-b990-70df35a7c26d |
ccbct8 | How are nutritional facts calculated? | I can't speak on if this is the method used in industry but there is a device called a calorimeter. I used it in college while studying chemistry it's basically a closed and sealed container that you ignite something in (in my case a piece of a candy bar) in a closed system and calculate the overall energy given off when the substance is completely ignited. It's a novel way to calculate calories. | 662f9f8f-546e-4ea4-8db6-6ace231b930d |
ccbf9t | If our bodies run on ATP and we can "replenish" that ATP from eating alone, why do we need to sleep to feel refreshed? | sleep isn't for collecting energy, it's for cleaning up chemical buildup in your brain (which is why you can't think right) and your muscles (which is why you feel fatigued) | c3d82d12-945f-4688-99b5-4b400c392628 |
ccbgd9 | how come when you get stabbed, at first you don’t feel anything? I heard it feels more like getting punched and you only notice until later. What causes you feel this? | Adrenaline is the number one hormone, when tensions are high you are temporarily unable to feel pain.
This allows you to fight or run from whatever is attacking you.
As you calm down, the level of adrenaline falls and you feel pain again and you notice you've been stabbed or shot | 78d0f181-fe24-4faf-b666-436ebca093db |
ccbh0y | Does air have surface tension? | Intermolecular forces in a gas a very weak compared to a liquid as they are generally much further apart except in high pressure situations. There is a level of "clumping" from these forces that could happen, but it's not going to be something like a droplet of gas floating through space, rather it's more likely to make the gas have a smaller volume than it otherwise would. | 8b8bfd90-af3a-4069-8188-49809cad098b |
ccbh0z | how does Bayesian inference work? | Where you go to school it rains half the time. So half the days during recess it's raining, and half it's not. When the recess bell rings, I ask you if it's raining or not. The best you can do is guess (say by flipping a fair coin). What if you *also* knew that little Timmy hated to get wet. Timmy will only go outside in the rain when he's really excited to play, about 10% of the time. And if it's sunny, he almost always goes out to play, except when he's in trouble. So 90% of the time if it's sunny he goes outside. So now if I tell you "it's raining, does Timmy go to recess?" you can look at the information and say, "probably not, Timmy hates rain." What Bayes theory tells you is how to turn this information around: What if you go to the restroom just before recess, and when you come back to class, you see Timmy at his desk doing homework. Now, *how likely is it that it's raining?* Your gut instinct is that it's probably raining, because you know Timmy would probably go outside if it were sunny. Bayes Theorem tells you how to calculate those odds.
Bayesian inference is the general process of using those ideas and any probabilities you can measure to make predictions by taking advantage of how those probabilities are related to each other. | 75a75eb4-e92d-4a0b-82cb-3a9308d19a4b |
ccbv3w | Why does pain often give a "throbbing" sensation? | Depending on what’s causing the pain, there are a few reasons that it might be felt as ‘throbbing’, aka coming periodically, or in waves:
First, the throbbing you’re feeling is most likely your own pulse.
Second, there are also other systems in your body that move to a rhythm - think of involuntary muscle movements, like giving birth, or vomiting, or orgasm.
Third, your nervous system functions like a circuit board - there are capacitors, which need to ‘fill up’ before they pass a signal on, and gates, which need to receive the right combination of inputs before outputting. Or think of how waves combine on the water - every once in a while two smaller waves will overlap and to make one big wave.
Finally, while all of those hint at mechanical reasons for why pain ‘signals’ might be read in waves, consider the practical reason: it’s harder to ignore a flashing light than it is to ignore a light that’s on full bright all the time. Your body is built to alert you to potentially dangerous conditions, pain is one mechanism for that. | bfcf75ed-3912-41c1-814a-8066e7bb5669 |
cccdb5 | How does cruise control work? | The rate at which fuel is pumped into the engine adjusts the speed of the vehicle. This is done through a valve that can be adjusted to allow more or less fuel in. That valve has two possible ways to open it. One is connected to the accelerator pedal which the driver presses. The further the pedal is pressed, the more the valve opens. The second method is through a cable which is connected to some electronics which adjust it depending on the vehicle's current speed. This second method is how the cruise control adjust acceleration. | e13198b0-0262-4ca7-aa99-65d083f183a6 |
ccclol | how jumping in to water from a high place is a suicide | When you hit water at high speed, it’s no longer soft and doesn’t flow around you. The force it applies back to the body is very large, so the impact you get is more or less the same as hitting concrete.
The upper limit to survive a fall into water is around 75m. That results in a ~95% fatality rate. | 0c08b415-a3bd-40b9-ae18-2e50a6b8f34f |
cccnx4 | Tuition Reimbursements and what it entitles. | It'll vary from company to company. In your example, your company will pay 100% of your tuition up to a maximum of $9000. So if you spend $1 or $9000 on tuition in a year and meet any other requirements such as grades/etc, they will reimburse you for 100% of that. If you spend $15000 on tuition in one year, they'll pay $9000. | 95a5ea26-7345-4761-a23a-db2ef6b1157c |
cccul5 | why is bacon so different from the rest of the pig? | Bacon is cured and often smoked. The curing and smoking process dramatically alters the flavour of the meat. If you smoked and cured a pork chop it would taste a lot like bacon (though it has less fat so it would be dry and tough, which is why we don't do this to chops or leaner cuts of meat). | df7ba5d7-b9a2-4b69-bc46-eff1bca3958c |
ccdhp8 | Why is a PIN more secure than a password in Windows 10? and why is considered a passwordless method? | PIN is tied to the device
One important difference between a password and a Hello PIN is that the PIN is tied to the specific device on which it was set up. That PIN is useless to anyone without that specific hardware. Someone who steals your password can sign in to your account from anywhere, but if they steal your PIN, they'd have to steal your physical device too!
Even you can't use that PIN anywhere except on that specific device. If you want to sign in on multiple devices, you have to set up Hello on each device. | e58a8c7a-f93c-4949-98ea-d0834e7848d7 |
ccdo67 | Why did Japan go further into a recession at 0% interest rates? | So everything in modern business is funded through debt. That means we can buy what will make us successful TODAY instead of grinding an inefficient business model until we can save enough to pay in cash. So long as everyone makes their payments, this is great because that means growth can start right away!
However, if the bank cuts loans to too many bad borrowers, and the borrowers take out too many loans that they know they can't make payments on, the bank will start running short on cash.
That means they need to up the interest rates, and that means growth stops, and that means businesses start failing, which means people lose jobs, which means more people stop making loan payments, which means the banks have less cash, which means interest rates go higher, which means more businesses fail, which means...failcascade.
That's a recession. Until someone injects the machine with some cash to get the money pump flowing again, the whole economy will come to a grinding halt because all but the safest borrowers now have to pay in cash because debt is expensive.
Japan's economic team tried to help their recession by offering 0% interest rates. That would theoretically encourage businesses to borrow, and start injecting money into the economy to get things going again. But that also implies the banks have money to give to these borrowers, which they don't, so the problem only gets worse.
Conversely, Obama started cutting checks from the US Treasury for the 2008/9 recession to fund infrastructure projects, the automotive industry, and giving the banks some liquid capital to start working with. Elizabeth Warren seems to favor a bottom-up approach and intends to tax the super-rich and start zeroing student loan debt to prevent a predicted recession around 2021. Which approach is better is extremely debatable.
However, all of these solutions only solve the "Today" problem. If lenders keep handing out loans to shit borrowers, the situation will just happen again. Drastic economic measures like 0% loans and bailout checks must be coupled with regulatory fixes to prevent the problem happening again.
But we all know that's not going to happen. It would be bad for business wouldn't it? | 38950df4-cd46-4331-84dc-6eab73de1b07 |
cceerk | Why is there no large animal with more than 2 eyes but spiders have a lot of eyes? | The last common ancestor of all vertebrates had two eyes and that's worked well enough. No mutation that gives more than two eyes has given a significant survival or reproductive advantage, so we've stuck with what works.
The arthropod body plan is a bit more flexible when it comes to numbers of things. You can have anywhere from 6 to 100 legs, plus 0 to 4 wings, 2 simple eyes, compound eyes, or 8 or whatever. | eedeaa1b-aacd-4da5-8d3b-0bbe5235a6ef |
ccenst | Why do tortoises live so long? | They have extremely slow natural processes. No real fear of predator also means no rush to pump out babies, slowing things down even further.
No offense, but I personally didn't know the answer to this question, so I literally just searched "Who do tortoises live so long" into google and regurgitated the info back to you.
_URL_0_ | 45079646-d94e-4d19-b89d-60e6a17e546f |
ccf7c4 | Why does the nose burn easier in the sun? Is it really because it is 1 inch closer to the sun? | It's because the sunlight is hitting it flat instead of at a really steep angle, so you're getting more energy per square inch.
There's no useful difference between 92.96 million miles and 92.96 million miles + one inch.
Now, you would burn easier on top of a mountain because there's significantly less atmosphere to shield you. | 0e2af61a-aadf-4c3d-ad81-9674de287e63 |
ccf83l | at the molecular level what is the difference between a dominant gene and a recessive gene? What makes the dominant gene dominant and the recessive gene recessive? | It depends, but in a simple case if it takes multiple pieces to make the the final time e.g multiple protein "subunits" to make a "protein-complex" then if any of them are defective, the whole thing doesn't work. Think of car tires where one or two of the four tires is flat (from the mutant gene) and the other two or three are fine. The care is not going anywhere with flat tires, so having one good gene does not help. Other genes/proteins work solo and if you have one bad copy the other good copy *might* be able to make up for it. Just one example.
Another way is if you have half as much of the good protein is that enough? If yes then the mutation is recessive, if not it is dominant. | ab9eeb33-6613-4a52-93c0-6b52abbcaec5 |
ccfaox | Why does the planet Venus rotate in the opposite direction than most other planets in the solar system? | We believe it had suffered a massive impact with a Mars sized object which was so devastating, at the right angle, and with enough energy, that it reversed it's rotation. During the formation of the solar system, we were a cloud of dust and gas. Over time, gravity caused that dust to clump together. This doesn't happen in a straight line, but along a curve in space. As the cloud condensed, that curve became more apparent. Gravity tugs on all, causing everything to fall in and along the same plane. This angular momentum normalizes, and the cloud of dust flattens out to an accretion disk. It's why all the planets orbit in the same direction, too. Over enough time, Venus's orbit will halt, and slowly start rotating back in the right direction. I don't know if the sun will explode or not by then... | fe15f60b-87c2-4f98-8dcf-8b563dc845ed |
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