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ll2hxc
|
Biology
|
- how much stronger are men on average than women? What is the female potential for strength and muscle gain? How long would it take for a woman to become as strong as the average man?
|
I don't have numbers for averages. As for potential for women squat and deadlift is about 70% of men while bench press is about 50%.
| 5 |
bt7vzy
|
Biology
|
what makes a voice sound pleasant/unpleasant?
|
Ok, I teach music at a high school for a living and one of the ensembles I teach is a choir. I've spent a lot of time thinking about this so let me clarify a couple of points. Everyone can be a pleasing singer. The first challenge is having a solid sense of pitch. [ URL_0 ]( URL_1 ) has a bunch of really excellent explanations of music theory and then a great ear training segment that can help a person develop an idea of pitch. So anyone can learn this and be able to sing in their own voice if they are willing to experiment. THAT BEING SAID, some people have much more resonant voices than others and there is fuck all we can do about that. It's really all about being as relaxed as possible when one sings. Some people happen to have a very relaxed neck setup and sound amazing with little effort. I used to think it had something to do with having a bigger build with a resonant chamber but I've seen small framed people have amazing sounds as well. I've had the pleasure of working with some singers who were had more notes then other people and there isn't anything we can do about it. It's like working out, you might not be able to have the exact body you want but if you exercise and lift some weights, you can still be attractive in your own way. Even the best of voices doesn't function without a sense of pitch. The best singers I had weren't the ones with the most notes, but the ones who could hear pitches, sing expressively, and remember their music.
| 10 |
dh1let
|
Economics
|
How can multiple gas stations right next to each other, with wildly different gas prices, all stay in business?
|
When approaching a cluster of fuel stations, as described, can you lawfully enter all of them from your position? Likely not. Maybe there’s two you can turn into safely and legally, but one has no exit going in your desired direction. So there’s four stations but only one option. That’s how it works here.
| 10 |
a1hmrj
|
Technology
|
Why online videos featuring advertisements play perfectly during the ad, but may barely buffer for the featured video?
|
Video sites will often cache popular videos on a server that is very close to you. So an advert, which is viewed by many people, will be streaming from a nearby server, but the actual video, which may be something a bit more obscure, is being served from the other side of the world.
| 1 |
iaua3z
|
Technology
|
How do noise cancelling headphones work?
|
Do you know how sound is a wave of energy? Well imagine a flat horizontal line, representing a sound wave. When it’s flat, let’s say there’s no energy so we hear silence. Now imagine a sound, and we see the sound represented as big hill-shaped bump of energy appear on our wave. Now imagine the mirror opposite of that bump of energy- a big valley shaped bump of energy the same size as our hill. It’s the negative version, or phase. If you were to play that wave on a speaker, he positive one would tell the speaker diaphragm to move one way, and the negative one would tell it to move the other way. So If those two waves overlap, they cancel each other out, and we’re back to a flat line, silence. What Noise cancelling headphones do is listen for external noises. They have microphones on the outside, and when they hear a noise they immediately generate the opposite wave of the noise they’re hearing, and pipe it into what you’re listening to, which cancels out that noise. This works best or is more noticeable with droning noises that are steady and ongoing- like airplane cabin noise, or a fan or air conditioner.
| 2 |
neq9rj
|
Other
|
what is Gnosticism?
|
Gnosticism was a version of Christianity shortly after Jesus lived. They believed Jesus brought them secret knowledge (gnosis, from which their name comes) that would allow them to escape this world and our bodies to go to a better, spiritual world when they died.
| 17 |
5os4r9
|
Economics
|
If I had $10 trillion and wanted to pay off the U.S.'s national debt, whom do i pay?
|
Bondholders, which means you technically can't pay the debt off early. When the US borrows money, they hold an auction, in which people give them 10,000 (usually in large multiples of $10,000) for the right to receive a few interest payments per year and $10,000 when the bond matures. These bondholders can be almost anyone (it's likely tough for Cubans to collect) and the bonds can be resold on the secondary markets. The US collectively owes whomever owns the bonds at any given moment (which includes almost everyone via mutual funds that own at least a few bonds). The US pays its debts because it wishes to maintain it's stellar credit rating (the US has never defaulted on a debt in it's entire history). That means when the US wants to borrow money, nearly everyone in the world is interested in lending money to the US.
| 16 |
gk3csk
|
Other
|
How are rainbows always in the same color order? Can there be reverse rainbows?
|
Light of different colours has a frequency. Red light is one frequency, green is another, blue is another and so on. Sunlight is made up of photons of all different frequencies. When light goes through rain it gets diffracted. That is, the light gets bent. The amount of bending is related to the frequency. High frequency (blue) gets bent less low frequency (red) and varying amounts in between.
| 3 |
8wundx
|
Other
|
Why do airlines force people to keep their seat belts on for so long when people in private planes can lay down, sleep, party, etc.?
|
This is like asking why at McDonalds you have to stand in line at the counter to get food, but at home you can just go to fridge and grab something to eat.
| 29 |
hnok0f
|
Mathematics
|
Why is it so hard to predict the weather? Why is it so hard for meteorologists to predict the weather? And how come so many different sources yield different predictions?
|
In general, we can actually predict weather very accurately, however, it is how that information is portrayed that causes confusion. Even a local news program is going to cover a relatively large area and will mostly have human defined boundaries. It is simultaneously unlikely that the entire area will have the exact same weather over the whole day or even an hour. So meteorologists need to convey potentially very different weather patterns to a large location in a single data point. For i stance when you hear that it is going to have a 40% chance of rain, the normal person assumes that his area has a 4 in 10 chance of getting rain. When it is subsequently sunny and cloudless, we say the weatherman was wrong. If you do get rain, you still complain that the weatherman was wrong because it was only a 40% chance, "so it shouldnt have happened" In reality, when there is a 40% chance of rain, it typically means that approx. 40% of the coverage area will get rain, and 60% wont. There likely are mistakes and obviously rounding comes into play when displaying round numbers like 30, 40 or 60%. But we are able to fairly accurately predict weather. Also to note your second question about why two areas can yeild different results, you cant exactly know how the particular source is defining their coverage area. Two overlapping but different coverage areas for the forecast could lead to two different results.
| 3 |
a6uvqt
|
Physics
|
The newly discovered state of matter, "Time Crystals." What are it's properties, and what does it mean for scientific advancements?
|
Would this be a 4 dimensional object, the crystal is stable over set units of time just like regular crystals are stable over units of space?
| 13 |
gndb6g
|
Economics
|
Why are farmers forced to destroy their products instead of bringing them to market? Recently I've seen news articles of farmers dumping milk and destroying livestock instead of bringing their products to marker. The articles implied this is a practice that isn't new, but only happens in certain conditions with the market. What forces farmers to do this?
|
For a pig to be brought to market, there has to be a facility to kill and butcher it, then package it for distribution. If those plants are closed, then they have no way to do that... farmers can't just deliver live pigs to your local grocery store! But it costs money to keep pigs alive and fed, and there are space considerations for where to put the not yet mature livestock if the older animals are still around. Similarly, milk needs to be stored, transported, pasteurized, and packaged or used to make other dairy within a certain amount of time. If there aren't trucks to haul the milk, or plants to process it are closed, then they need to do something with it -- the cows are going to need to be milked again tomorrow! And they only have storage capacity on-site for so much.
| 4 |
5xl43i
|
Culture
|
Why are so many US veterans homeless? Why are they in this position or how did they get to this point (generally speaking)
|
Honestly, certification. When I was in, I maintained servers, worked on equipment worth billions in operations and in support of the entire Pacific Rim. I was a system administrator as well and could debug accounts as well as work on the circuits to connect two persons on a line through multitudes of different cryptographic and plain systems - from the highest of Classifications to Unclass bullshit. None of that is transferable. They all want college degrees or certs from COMP-TIA. Don't have it? It doesn't matter what the fuck that training paper says you can do when you get out. I went from that straight to unemployment while looking for any civilian job. If I wasn't charismatic and able to talk my way into work when I really need to, I'd be homeless as well. Now I Scuba Dive. I went from facilitating international rendezvous over secure circuits and globally administrative duties... to working at a tattoo shop, then an arcade, now Scuba Diving and doing college. None of your skills are marketable. Nobody gives a shit. They tried to remedy this with TAPS - when you get out they make you take a class for resume writing. Guess what? No civilian certs? You have a really long piece of toilet paper unless you want to go back into government work.
| 43 |
c1ehj3
|
Technology
|
Why do some tail lights appear to flicker in dashcam videos?
|
Old filament lights won't do this, modern LED lights will, the brightness of the light is varied by switching the supply on and off rapidly the on time and off time can be varied, the longer it's on the brighter the light, this switching happens at something like a thousand times a second, the human eye can't detect that flicker but the dash cam has a frame rate that, although different from the LED flashing speed, will occasionally syncronise and capture several frames when the LED is off. It won't capture the same off event but just a series of different ones but it allows you to see the flashing, it is called aliasing, and it happens with digital sampling of many different types of signals.
| 2 |
dksxei
|
Economics
|
How is America the wealthiest country with the amount of debt it has?
|
It's not. Also, US government debt is also considered a good investment opportunity and would freak people it if they tried to pay it all off
| 1 |
g1kwzi
|
Biology
|
When you close your eyes and try to hear a familiar voice in your head, what’s really happening? How are our brains so good at recreating almost every voice we know? The same applies to reading any given text/ sentence using someone else’s voice
|
I dont think this, along with imagining people's faces, is true for everyone - strange stuff!
| 1 |
dfteul
|
Economics
|
What exactly does “cash back” mean on credit cards, car purchases, etc?
|
The cynical answer is: you get a very small percentage of any item spend transferred back into your account/balance. This tiny amount is usually more than offset by the crappy interest rate and charges you are suffering with, but it supplies a "feelgood" factor to the customer.
| 1 |
h7ndoj
|
Physics
|
There are colors beyond our comprehension? I was explaining to my younger sibling the concept of the spectrum of light more specifically the fact that only a sliver of light can be seen by humans. I know that other animals see in infrared and ultraviolet but what exactly does that mean? What color is infrared? What color is ultraviolet? And why can’t we see these colors? Many thanks! -a fellow older bro
|
We have little sensors in our eyeballs that respond to different wavelengths of light. Our brain interprets different mixes of these little sensors firing off as the 'colour'. Colour is our subjective interpretation of this sensor data. Animals that can see different wavelengths of light have different sensors. The colour of infrared or ultra-violet to them would be their brain's subjective interpretation of this sensor data. We can't see these colours because evolution has not deemed it necessary for our survival, ergo we never developed the sensors to do it.
| 4 |
f21pdq
|
Biology
|
Why is it best for someone with frostbite to warm up slowly? It seems like the best idea would be to warm them up as quickly as possible, but I’ve heard that’s not the right course of action. Why should you warm them up slowly? And what happens if they warm up too quickly? I’m from the Southeastern US, so I have no experience with extreme cold or frostbite, I’m merely curious
|
Frostbite or hypothermia? In hypothermia, or low body temperature, you rewarm slowly because a rapid change would put stress on the heart.
| 5 |
9ulr05
|
Other
|
Left vs. Right in politics
|
I have a degree in political science and I don’t know the true answer to this. The correct answer is probably that politics is much more complex to be summed up in terms of simply left and right and we should probably modify the term. I see left and right as simply and solely an economic spectrum. I think claiming Fascism to be a far-right form of government is a misnomer. It’s pure authoritarianism and isn’t really a free market capitalist ideal. Nor a socialist or communist one either. While the opposite of Fascism might be Anarchy, I wouldn’t characterize that as far left either... Explain Politics to a 5 year old, Eh. Well it doesn’t matter five year olds can’t vote.
| 5 |
o5n9nw
|
Chemistry
|
How can people have fires inside igloos without them melting through the ice? Edit: Thanks for the awards! First time i've ever received any at all!
|
What happens is the rough inside later of the igloo melts a little bit at first but the super cold ice behind it which is being kept cold by the outside temperatures freezes it again in to a smooth crust. Because there's now less surface area the warm inside air is less effective at melting the surrounding ice. So basically it's a constant battle between the fire inside warming up the air and the ice and cold air keeping the structure frozen, and the achieve a balance at some point.
| 18 |
acpww2
|
Economics
|
Why are we taxed when we get our paycheck and then again when we spend the money? Isn't this double taxing? I just feel I'm getting taxed twice for all the money I make. What's the deal here?
|
Whenever money changes owners, a little bit of it gets taken as a fee(tax). When money goes to you, it is from your employer. (so you pay Income tax) When money goes to a store, it is from you. (so the store pays Sales tax) Just so happens that the store is transparent in passing that cost on to you, so it feels like a double whammy. The real real crazy one is property tax, which is basically rent you pay to the government every year for the privelidge of "owning" land.
| 3 |
6os8fm
|
Biology
|
Why do my eyes get all bloodshot when my allergies flair up?
|
Causes the activation of allergenic mediated mast cells which subsequently release histamine into the body, which THEN causes vasodialiation or expansion of the blood vessels, causing a perceivable "redness" in the eyes and elsewhere
| 1 |
lxamui
|
Physics
|
Maybe explain like I'm 1 years old... Just read an article on a team of researchers who recently created a video of a Space-Time crystal. Pls can someone explain in the most basic way possible what a time crystal is? I've read previousposts on this and I still don't understand :( Link to article is [here]( URL_0 ).
|
From my understanding this is basically a metronome. It’s a crystal that moves on the atomic level in a patterns at regular intervals. So this could be used to measure time extremely accurately. A lot of times you see that a watch has quartz in it and that is because quartz is a crystal that is used for measuring time.
| 3 |
7nt1z0
|
Culture
|
IF hot peppers originated in North America, how did they become such crucial parts of so many nation's cuisines? How long would it have taken?
|
They were brought by the Spanish and Portuguese to their homelands and trading partners. And not just hot peppers: potatoes and tomatoes, too. Indian food was very, very different before.
| 2 |
j1d94z
|
Technology
|
Why did old dial up internet make that screeching sound while connecting? [dial up screeching sound]( URL_0 )
|
Dial-up connections send/receive data as sounds over the phone line. The "screeching sound" you're referring to is the handshake, where both modems were negotiating how to communicate with each other. That part was purposefully configured so that the user could hear it, so that you could troubleshoot common problems, like a busy signal, or a wrong number. Once the connection was established, the sound stopped being played through speakers for you to hear, but they kept being played over the phone line between the two modems, because that's how data was transferred. [This blog post]( URL_0 ) has a great dissection of the parts of a dial-up handshake.
| 4 |
hlzjid
|
Biology
|
when we accidentally breath in water, how does the body remove that water from the lungs?
|
Most of it: cough it out! What's left of that: the lungs have a microscopic conveyer belt called "cilia" that can bring some up (probably mixed with mucous, probably still coughing it up too) What's left after that: can be absorbed. Pee it out eventually.
| 3 |
677gc8
|
Biology
|
If parrots are so smart, why can't they be potty trained?
|
Some animals have a natural instinct to control their defecation. Some do it for sanitation, others to prevent detection. Other do not, and just poop when and wherever. You have that luxury when you are high up in a tree, above everything else. Controlling it would be like you trying to blink only at certain times. You could do it for a while, but it would be unnatural and exhausting.
| 3 |
azue0q
|
Other
|
If marbling of the meat determines its quality, why do people trim off the fat? Just curious, shouldn't leaner meats be higher value if were gonna trim the fat anyways?
|
It's like saying: If you like butter on your toast, why don't you just eat a stick of butter?
| 4 |
n1nxe7
|
Other
|
How did human civilisation come to a consensus on how long a second is?
|
It originated with the ancient Sumerians, who had a sexagesimal system of mathematics (a numeral system with sixty as its base). The Babylonians adopted the Sumerian method, which later was adopted by the Greeks, and then adopted by the Romans. Thereafter the practice spread throughout Western Europe and eventually the world, via the Roman Empire and later, via European colonization and trade.
| 3 |
912jug
|
Physics
|
How is that the people that do Parkour don't break/hurt their legs when jumping from ridiculous heights by just rolling when they land ? Some of the dont even seem like they took a lot of speed to make the jump, more like they just jumped down straight to the floor, but even so they manage to land unscratched by rolling when they land, where does the force of the fall goes ?
|
Basically what the roll does is slow down how fast a person loses their downward momentum, which reduces the amount of pressure that the body has to endure, allowing a person to fall further without being injured
| 2 |
e9gbf9
|
Biology
|
why do you pee so much from drinking alcohol? Like even if it's just a few shots, why does the body produces so much urine from just a few shots or drinks?
|
It's not just the volume of liquid you consume. Alcohol is itself a diuretic, meaning it makes you pee more. Alcohol reduces the production of a hormone called vasopressin, which tells your kidneys to reabsorb water rather than flush it out through the bladder. Basically, it disrupts the normal process of your kidneys reabsorbing water and instead tells them to send it to your bladder as urine instead.
| 3 |
jc41at
|
Biology
|
Why does scratching feel so good when it ends up in a much worse rash than before?
|
Scratching sends a low level pain that distracts your brain from focusing on the itching. It can also help to slap the itchy area so that you can get the same distraction without causing damage with scratching.
| 1 |
5s0whp
|
Other
|
Why is a terrorist organization like ISIS so difficult to defeat? With so many powerful nations actively fighting them, how do they still have a leg to stand on?
|
Let's not forget that the US is still lowkey supplying and financing ISIS, so they'll destabilize the Middle East. Don't have time to link any articles right now. Ut spend more than 5 seconds on Google and you'll fund plenty about it, from reputable sources.
| 61 |
ceo827
|
Chemistry
|
How the human body can lose tolerance to alcohol if it has not been exposed to alcohol over a long period of time.
|
Here’s my response from your first post that got removed. Not sure if you can see it anymore: Well, your body is always trying to maintain homeostasis, or a constant healthy state. When you regularly consume alcohol, your body learns this and is prepared to adapt its metabolism of the drug and other things to maintain homeostasis better, even when you’re drunk/high. Essentially your body is trying to keep you from being drunk because being drunk is bad and your body interprets alcohol as a poison. When you stop consuming alcohol or any drug for an extended period of time, your body sees the substance as “less of a threat” to its homeostasis, and thus lets its guard down and “forgets about it.”
| 2 |
60u2yk
|
Engineering
|
Why can you switch gears without using the clutch? New to this. A co-worker was trying to explain to me how he can shift without using the clutch, but I'm pretty sure he confused himself while confusing me.
|
If you find the sweet spot in the rpm's, then the clutch becomes unnecessary. Since there is no tension on the gears it can shift in and out smoothly.
| 3 |
5slz5w
|
Biology
|
What determines if seeds grow to be a plant? I had this really weird conversation with a colleague, and unfortunately, I could not give a good rebuttal. My colleague claims that not all seeds grow into plants because only a few of them are "ensouled" (I am German, he used the word "beseelt"). His example was that a lot of acorn fall of an oak but the do not grow into a new tree unless they are, well, ensouled. So, what is the scientific reason that not all seeds grow into plants?
|
It depends on a lot. Some of them need certain fungi, others need to be set on fire before they can sprout. Some need the right soil, some need a certain amount of water, some need to explode, some need to be eaten first, and some need enough nutrients. Genetics does not play much of a factor because they're tough and mutations rarely stop a plant from growing.
| 3 |
jn9059
|
Biology
|
What difference does it make to the body to do 5x20 push-ups with short breaks vs. 5x20 push-ups spread throughout the day?
|
The same difference between walking a marathon in one day and walking the same distance over the course of a month. Your muscles get time to rest.
| 4 |
7tdz5x
|
Biology
|
Why is water indispensable for all living things?
|
Basically, life is a bunch of chemical reactions that can only really take place in a watery environment. In order for the parts of your cells to do their business they must be in a watery environment.
| 1 |
5p6p49
|
Engineering
|
why does the tech industry advance so much faster than most other industries? I feel like every 2 years our technology is almost transformed. 10 years ago I would never imagined the technologies today (Alexa, Surface Pro whatnot) yet most other industries has not experienced this rapid of a growth. For example, in the medical industry, we are still using the same antibiotics we did 20 years ago. Why is this?
|
The fastest innovations in tech are in the area of computers and software. The reason innovation happens so fast in that space is that the cost to building and trying out an idea is so small. If you think of an idea, you can try it out and build it right away. Compare that to something like medicine, where it takes years to figure out if a drug is working or not - or mechanical engineering, where it might take weeks or months to physically construct a device or machine to test out an idea. In software, you can think of something, program it, and try it out immediately. That leads to rapid iteration and much faster development cycles.
| 1 |
dkdx20
|
Physics
|
Why isn’t Ohm’s law universal?
|
Ohms law holds for a simple conductor, but not everything is simple. A diode, for instance - you can't apply ohms law to a diode, because the current through it changes markedly when it exceeds its junction voltage or its breakdown voltage. The resistance of substances also changes with temperature. While you hold the temperature constant, ohms law applies; but current flow through a resistor will heat it up, which will increase its resistance. This is what we mean when we call a light globe a 'non-ohmic conductor', because its resistance when cold is lower than when it is glowing. So, in the real world, Ohms law becomes a useful approximation.
| 1 |
5pqu41
|
Other
|
Why does the water from a plastic bottle taste fine after being on the store shelf for months, yet the day after I put my own tap water in there it tastes of plastic?
|
It also has not been in contact with air while inside the bottle. You'll note that water tastes different when left in a glass overnight as well. That's because the water is absorbing CO2, etc. from the air, altering the taste and making it seem "flat."
| 2 |
8zfau6
|
Chemistry
|
Why do (AA & AAA) batteries in a package seem to very rarely leak even after sitting in the cupboard for years and batteries left in a dormant device leak after a much shorter time? Why do (AA & AAA) batteries in a package seem to very rarely leak even after sitting in the cupboard for years and batteries left in a dormant device leak after a much shorter time? (....And then ruin the controller unit on my gas fireplace)
|
The corrosion is caused by hydrogen gas escaping the battery, allowing the battery to leak, this still happens when on the shelf, but at a slower rate. When your device is 'off' there's a small amount of drain happening causing extra gas to be produced, also depending on what the contacts are made of on the device they made corrode as well (causing it to look like more battery corrosion).
| 2 |
hnb5ld
|
Physics
|
what is happening when a cloud is formed around a Jet when breaking the sound barrier? ELI5: what is happening when a cloud is formed around a Jet when breaking the sound barrier?
|
I think you are referring to vapor cones, during transonic speeds (around mach 1) low pressure and temperature zones are created around the aircraft which lower the dew point of air. This will cause water to condensate and form clouds. A similar effect is observed when aircraft perform high g manoeuvres
| 2 |
kt6zn9
|
Technology
|
how those "I'm not a robot" checks on websites work.
|
They're usually measuring how fast clicks happen and how the mouse is moving across the screen. A bot is usually programmed to "snap" or teleport instantly to the images or checkbox, and that's a giveaway that it's almost certainly not a human checking the box. Same thing if it just receives an instant click as soon as the box appears, since most people don't have that fast of a reaction time.
| 1 |
9jvmzn
|
Other
|
why do people look better/worse in person than in a photo?
|
There could be lots of reasons to consider: * Depth - when you see something in 3D you see lots of features and structure that doesn't look the same as on a 2D picture. * Angles - When you look at a person in real life, they're mostly moving around, and our brain has a tendency to add up the things it knows are there but can't see. There are features that can be hidden in pictures but blatant in real life and vice versa. * Lighting - Really the same as angles but important enough to highlight on its own -- Shadows and lighting can play a big role in hiding or making certain features more prominent. * Lens - they can distort shapes/structures, making something seem more slender/wide/tall/short etc. * Quality - should be obvious but again it can blur some unappealing features or emphasize appealing ones. * Focus - see lens/shadows/lighting And finally, the fact you see something move in 3D versus a static 2D image. There's just a psychological feel that I can't really explain but I know exists across at least my friend group. You just feel the warmth of a person in front of you, that isn't there when you look at their photo with no emotions attached to it.
| 1 |
abyh4n
|
Biology
|
If the natural temperature of the human body is around 37 celsius, how come an outside temperature of 35 celsius *feels* like hot hell? Shouldn't it feel normal?
|
37 is the inside of your body. your body constantly generates heat, and thus you need to constantly lose heat to not cook. Your body doesn't actually measure temperature, it measures how fast you are losing heat. If its too fast you feel cold, if its too slow you feel hot.
| 1 |
hxnjnl
|
Other
|
How do bugs get home when they get stuck in your car and then let out far away? Such as if a wasp gets in your car and you let it out after you get on the highway. Does it sense pheromones from home or something? Does it join a new colony? Does it create a new one, does it die?
|
Wasps: No. No. Possibly. Maybe. Bees: No. No. No. Yes. You would think wasps/bees would use pheromones to find the nest but they don't. They scout the area around it, making note of objects in the area, and just keep widening that area around home as much as they need to.
| 2 |
b54gku
|
Chemistry
|
Why is "proof" on alcoholic beverages twice the percentage of alcoholic content? Why not simply just label the percentage?
|
TLDR: Because that's the way it was defined. Back in the 16th century a relatively simple way to proof that a product had at least a certain amount of alcohol in it was mixing a bit of it with a bit of gunpowder and then lighting it on fire. If it burned it had at least 57.15% alcohol by volume. That was considered 100 proof (back then). That was important since if you for example sent a ship to the Carribbean you wouldn't want to go through all that expense to transport rum that was watered down. Eventually more accurate measurements were developed and specifying alcohol content by percentage of volume (ABV) became the norm. Still, people liked the sound of "100 proof rum" and such so that stuck around mostly for advertising. But converting between the original proof measurement and the new ABV wasn't convenient. So it was decided to just redefine proof as twice the ABV (it also probably didn't hurt that "new proof" was slightly weaker and thus cheaper to make than "old proof").
| 10 |
o5nok5
|
Other
|
options trading.
|
With respect to stocks, options contracts are essentially bets that the underlying stock price will (or will not, if writing them) move at least a certain amount in a single direction by a certain expiration date.
| 1 |
cy76qp
|
Biology
|
When you're lying/sleeping on your side why do you sometimes get an overwhelming urge to roll onto your other side?
|
It's probably to prevent bedsores. If you never moved when sleeping you'd end up with damage at certain pressure points depending on how your weight was distributed. Moving around prevents that damage. But I don't have a link proving this.
| 4 |
6pa1qs
|
Technology
|
What purpose did modems serve before the internet? I was born in 2000 so I'm obviously a bit too young to have any firsthand knowledge of pre-internet computing, but I've taken up an interest in certain retro tech channels like The 8-Bit Guy and I see that a lot of older computers have ports to connect modems onto them, even computers from as far back as 1981. I know the internet didn't come around until the early 90s, so what were modems used for in those days? Did they all have some equivalent to a BBS or was there some other use that I'm just not seeing?
|
The *World Wide Web* (which is the Internet as anyone born after 2000 would know it) began in the early 90s with the creation of the Domain Name Service. With DNS, you can type an address into a browser and the computer handles all the back-end things for connecting and downloading. Before that point, we **still had internet** but it was a lot more primitive. Early modems were even as simple as [A device you literally plug your phone handset into]( URL_0 ) and you'd dial a physical phone number. Your computer would then "handshake" with the other computer and they'd begin sending data over the analog phone line. The earliest data being sent back and forth were military and university communications. Fun fact: You may think the internet was invented in the 90s, but [the first email was sent in 1971]( URL_1 )
| 4 |
9v9fir
|
Technology
|
How do Mesh Wifi sustain speeds when a Repeater drops a speed to half? I understand that, using a Repeater results in our internet speed being cut in half as it has to re-encode the packets before broadcasting. But, isn't mesh wifi basically a primary router coupled with a number of repeaters?
|
Using a repeater does not necessarily need to cut the speed in half. Many repeaters and mesh routers use different channels and sometimes frequencies to communicate with each other. So you could have full speed on client side and between the APs.
| 4 |
fmu1bg
|
Biology
|
How is cancer so deadly but a person feels fine one day then the next they are told they have 4 months to live?
|
Why does Cancer come back after a successful treatment?
| 13 |
9d3vtc
|
Technology
|
Why do solar panels stop working? According to a recent BBC article, after 30 years or so solar panels are end-of-life and the scrap is no good for anything but landfill. What stops them working? What makes the scrap unusable?
|
A quick search on the BBC website reveals no such article, do you have a source? You might be interested to hear that [a solar panel recycling plant has opened in France]( URL_0 ), so your statement that "the scrap is no good for anything but landfill" seems to be false. According to the Reuters article "The robots in Veolia’s new plant dissemble (sic) the panels to recuperate glass, silicon, plastics, copper and silver, which are crushed into granulates that can used to make new panels." and "Veolia said it aims to recycle all decommissioned PV panels in France".
| 3 |
8v1s26
|
Biology
|
What is it about mint that causes the cold sensation?
|
Simply put - the receptors in your mouth that respond to menthol (mint) are the same receptors that respond to cold temperatures. When these receptors are activated it sends the signal for cold to our brains
| 1 |
9xtjxh
|
Technology
|
What does it mean when a computer crashes?
|
Computers follow orders, and they do it (for the most part) blindly. If an impossible order is given (like when you send it looking for something that doesn't exist), it crashes. Similarly if an infinite order is given (you can literally order your computer to loop infinitely, and it'll get stuck in the infinite loop), the computer will "crash" in the sense that 100% of available resources are tied up in something literally infinite. In the most general sense, a computer is the ultimate grammar nazi combined with the most obedient servant. Grammar error in your code? Computer says "This whole book is unreadable" and your program crashes. If the grammar error is in the *operating system itself*, then the computer crashes entirely unless the programmers also included a path around the crash (programmers commonly create orders for the computers that are essentially "Try to do A, but if that creates an error, then do B").
| 1 |
9tu6rg
|
Biology
|
If brain cells (neurons) are specialized cells which don't divide, how does brain cancer exist?
|
The brain cancers are usually not the neurons but the supporting cells around them, like glial cells. Those supporting cells do replicate more frequently than neurons do, and is typically what is referred to as brain cancer
| 12 |
kn9m3f
|
Biology
|
How do we know, wether a sound is made in front or behind us, even though we only have ears on the sides?
|
For starters: [here is a really amazing video]( URL_0 ) that goes into tons of details and demonstrates how we determine the direction of a noise. We use two main ways to determine the direction of a noise. First we determine left and right based on the time delay from one ear to the other. If a sound comes from your right side it reaches your right ear a fraction of a second sooner and is a little louder. Sensing if a sound is above, below, or behind you is a bit harder. Your ear lobes reflect sound into your ear drum differently depending on the way the sound bounces off them. In the video I linked he messes with this ability by packing some play dough into his subject’s ear lobes. While they can still determine if a sound is from the left or right, it totally ruins the ability to determine other directions. The play dough changes the way sound is reflected and the brain doesn’t know how to compensate. The video is really worth a watch, smarter everyday is one of the best channels on YouTube.
| 1 |
d1ms44
|
Biology
|
Why does your nose get stuffy or run when you cry?
|
From what I've read before, your head has a bunch of tubes and holes in it, and basically everything is connected. What I've read is that some of the tears "drain" into your nose, and that's one of the main reasons why your nose runs when you cry
| 1 |
jkz1ah
|
Economics
|
how come a company can beat all forecasts in earnings and the stock can still take a plunge?
|
There's a ton of factors that go into how investors see the value of a company - they are looking at the short-term (how much a company is making now) and the long-term (what the company will be doing in a year, five years, ten years). A company can make a gazillion dollars in one quarter, but if the CEO announced he is retiring and the new CEO has a reputation of ruining companies, that can affect the value of the stock. Maybe they announced they're going to invest 80% of that money into some completely new area of operations that they have no experience in and could wind up losing a lot of money. Maybe the government is considering new regulations that could severely limit what the company does in the future, so even if they made a ton of money this year, they might not have the same environment/conditions to make that money next year.
| 2 |
gujwyk
|
Technology
|
Why do OLED screen burn ? I've seen plenty of sources telling it's because some pixels stayed static for so long, ok, but that's not an issue with LCD. Why is it different for OLED and how come you can damage a screen just like that ?
|
An LCD works by filtering the light from an always-on white backlight. In older/cheaper screens, that backlight would be white fluorescent tubes, in newer ones it's a bank of white LEDs. On top of this is a coloured filter layer, and then the LCD layer itself, which restricts light. If you're displaying a black screen it filters all the light, if you're displaying a perfectly red screen it filters out all the blue and green, for example, leaving just the red. Point is, the white backlight is the light source. In an OLED screen, every pixel consists of a red, blue, and green LED, and it generates its own light. LEDs naturally get dimmer as they age, anyone who has used a set of LED christmas lights over multiple years will have noticed this - older sets get dimmer. So in areas of the screen that display a brighter image, for a long time, the LEDs responsible for those areas will get dimmer overall compared to the rest of the LEDs. So if you then try and display a white screen, the LEDs that are more worn out will show as a dimmer area of the screen (or more likely, show a colour cast, because certain colours of LEDs wear faster than others)
| 3 |
5siojz
|
Technology
|
If electricity travels so fast, why does it take so long to charge a battery?
|
Actually the electricity travels slow. It's the energy which travels fast. Pipe full of tennis balls, where the balls are the electricity? Push one ball into the pipe, and a different ball pops out of the far end. Electricity is like pedaling a bike with a very loooong chain, and your rear wheel is at the end of a mile-long bike frame. The chain is the electricity. The bike wheel wheel still turns almost instantly as soon as you pedal. In other words, all wires are already full of electricity, and "charging" a battery is only forcing electricity through it and back out again. A battery is a chemically-powered electricity pump. Charging a battery is converting some waste-products into the chemical fuel (it's usually a metal like zinc, lithium, lead.) Battery charge rate, that's a separate issue. Charging a battery is a bit like winding up an old-style watch or alarm clock. You can turn the little winding key quite fast, but it still takes a whole lot of turns in order to wind the spring up all the way. And if you spin it too fast, the gears will be damaged. Hey, why don't we just charge batteries using much higher current? After all, the more the amperes, the faster the battery drains out (and the faster it recharges.) Only trouble is, batteries have a sort of "internal friction." If we run the electricity through them too quickly, they heat up inside. That might be OK, but you take a chance in ruining the battery. ALso, batteries are full of wet chemicals, and **don't let the water boil, or the battery will explode.** That's where insurance companies come in. In products for sale, the rate of charging is carefully controlled, and it's kept far from "the edge." Unsafe battery recharge, we might call it... "edging?" To charge a battery at max rate, you'll want to have it right on the edge of a violent explosion. (Cold water might help.)
| 4 |
7qckts
|
Biology
|
Why is 70% isoprpyl alcohol better than 99%? The title says it all. Edit: actually the title didn't say it all. I meant a better disinfectant.
|
my ex was a clinical biochemistry lab instructor and told me this: 100% alcohol causes the exterior of the cell membrane to harden right up, forming a good barrier to protect the inside. A 70% solution is deadly to the cell membrane and innards, because the water component slows down the hardening and allows the alcohol to penetrate the membrane before it toughens up. So the alcohol that rides through the membrane into the inner part of the cell does its work quite well, killing it.
| 4 |
9fntaw
|
Biology
|
why non-human mammals stop drinking mother's milk. I realize that humans drink mother's milk as infants. I also realize that we make a transfer, at some point, to drinking cow's milk. I dont want to get into why we shouldn't be drinking cow's milk. My question is: why do other mammals stop feeding from the mother's teet at a certain point in their physical development? Do they become inable to process the enzymes? I did a couple quick searches on Google, and only got results for "A MILLION REASONS WHY YOU ARE AN IDIOT FOR DRINKING MILK!!!"
|
Animals usually become lactose intolerant as they grow up. They can't drink milk from their mother because of a few reasons: 1. Momma don't live forever. 2. Chuldren usually separate once they grow up, and live on their own. 3. The amount of energy required to sustain oneself, as well as to produce milk *for an adult* is just too much. We too were mostly lactose intolerant, except the rare few of us, who, during periods of starvation, were much more likely to survive off of raw cow milk. Now most of us are tolerant to milk.
| 6 |
7r5ryn
|
Physics
|
Why do cars slightly move up when your foot isn’t touching the gas pedal?
|
Only ones with automatic transmissions do. A torque converter is between the engine and drive wheels. When the wheels are not turning but the engine is, the torque converter still tries to rotate the wheels.
| 2 |
a69ffp
|
Mathematics
|
Is there a scientific principle which explains the constant flow and presence of people in airplanes / at stores / restaurants / calling Support lines etc? This is a question that has always fascinated me from the psychological or scientific perspective. Why is it that there are always people (I would assume mostly different people) doing a given activity such as being on an airplane, shopping at a store, eating at a restaurant, etc? Why isn’t there a day that the scientific law does not hold true and nobody psychologically determines a need or desire to show up at a given place and it goes empty for that day, just by sheer chance? I’m sure the law of averages has something to do with it, but is there something deeper that explains this phenomenon? Thank you!
|
Oh my gosh, I didn’t know there was a name for this! For me it always came to me with regard to streets and intersections in all the various towns I’ve lived in. Many times I would think, there will always be a car at this intersection, always, no matter what time of day or night, no matter where I am, some other person will be driving here. And then I would appreciate how “weird” that is that there will always be a person awake and driving at, say 3am, every night, and every other time every night, everywhere, etc.
| 3 |
5xegx5
|
Other
|
Why do coupons have a little note that says that their cash value is 1/100 of a cent?
|
Follow up question(s): If a coupon has a cash value, does that value expire, as does that coupon's intended effect? What I'm trying to get at is: should I stop throwing away expired fast food coupons in order to save up for a shiny new penny or would it be for naught? And if they do expire, then would it even be possible to ever redeem them for the cash value? Can I redeem, say, an individual coupon worth 1/100 of a cent before it expires and get a check or something? Or do you have to redeem them in 1 cent multiples?
| 3 |
lj2vrk
|
Other
|
Why do shoes narrow at the toes? This is not how feet are shaped. What's the deal?
|
Good question. Aesthetics. Not all shoes do. In some designs, the toe area is wider, mimicking your actual foot, like Crocs and clogs. They are popular bc they are comfortable.
| 3 |
63dbw1
|
Other
|
Do glass marbles have any industrial, commercial, or manufacturing use - or are they 100% purely a plaything?
|
I know some reflux column stills will use them as a condenser medium. The vapors collect, cool, and flow back into the still. This is done in this style still to keep the column clean.
| 16 |
9hvzg9
|
Technology
|
How do movies make such realistic-looking fictional characters? I'm talking about the likes of [Thanos]( URL_0 ) from Infinity War; these characters look so incredibly detailed and their movements and voicing so natural, that it's almost hard to imagine how they were made. Are they simply modelled in extremely detailed 3D? Are they computer-edited scenes of real people in heavy makeup? Why are video games so behind on character movements and face animations compared to these movie characters?
|
In movies you use motion and face capture of real actors most of the time so you can create another face using there movement and voice. You can look hot they are captured URL_0 That in combination with a large special effect team that can look at the face and change how it move compared to a human face. So you need to preform all possible moment with a actor and find a way to stitch them together as you can constantly look at a character in a game but a movie will cut to another scene. So you could do a full motion but you would need to do more then in a move as the number of possible motion is a game is large compare to a simple fix script in a move. Doing it for a film is expensive but game would be more complex and you would need to do that for all characters. So it would be expensive. Another problem is the uncanny valley. look at URL_2 and notice that the human face look ok but the alien look good. The problem is that we know how human looks so we can see any imperfection. So a almost perfect human look worse then bad human imitation. The bad imitation is obvious not a human so we accept it. But the almost human face is intreprited as a human but there is somting wrong with them. So we like the bad face better A example is the Recreated Grand Moff Tarkin and princess Leia from Rogue One URL_1 Ships, androids and aliens look good but the human does not. So it is extremely hard to create good human faces that is what is common in games.
| 2 |
a5w3u9
|
Engineering
|
What's a blow off valve and why is it being used mostly in Track cars?
|
Blow a lot of air out of your mouth and while doing that cover your mouth. The air has nowhere to go right? That’s what a blow off valve is for. When your turbo is producing boost and you let off the throttle all of that air runs into your closed throttle valve. The BOV allows that air to escape so you don’t get a backup of air into the turbo. That backup of air can damage the turbo and it can also slow it down which makes it much more laggy when you get back on the throttle.
| 1 |
72av5j
|
Technology
|
Why do 'bionic' hands/arms have such stilted and unrealistic animations, when this creepy robot puppet can have such natural fluid motion? Compare [this dancing...thing]( URL_0 ), to what is apparently humanity's best attempt at creating a natural looking and functional [prosthetic limb]( URL_1 ). I get that the limb has to be functional (able to grip and hold objects without crushing or dropping them) and that the puppet is probably a very lightweight material such as styrofoam, but it seems like the servos powering the bionic limb should be able to be programmed with the same sort of inverse/forward(?) kinematic animations. Perhaps the puppet is using some sort of string/ligament system instead, perhaps giving it the naturalistic movement, but then why can't a functional limb be built around this system? What limitations are preventing such a realistic looking arm (at least in terms of behaviour) and is anybody actively trying to overcome these limitations?
|
Cost is a factor too. The programming and engineering needed for making something functional and practical is one cost. Then there’s the programming and engineering needed to make it realistic and fluid, that would tack on the cost for people who need the limbs. There’s also the likelihood that you will sacrifice the former when including the latter. And people who need arms or hands would be better off with functionality than fluidity.
| 3 |
lm2wan
|
Biology
|
If a person is brain dead, but kept alive by machines, why does the brain itself not start to decompose?
|
The brain is still alive in the sense that the cells that make it up are still alive. The machines are providing oxygen and nutrients to the cells of the body. Brain death is a bit of a misname because the brain is still alive, but it is no longer functioning as it normally would.
| 2 |
iwf1s5
|
Engineering
|
Why are disposable razors only good for one use while something like a safety razor can be reused for multiple shaves? I can’t decide whether it’s a difference in steel quality that causes disposables to dull quicker, or if it’s related to microbe buildup on the blade and avoidance of folliculitis (in which case, wouldn’t you want to dispose or sterilize both after each use?). Or maybe it’s just a marketing strategy to sell more disposables?
|
Disposable razors are quite often difficult to clean, so they clog up with bristles. Have a look; sometimes there’s no “vents” behind the blade so they’re useless after one shave. Safety razors can be cleaned more easily and don’t clog.
| 6 |
cqmu67
|
Culture
|
meaning of neo Nazis vs Nazi? What is the difference between a neo nazi be a Nazi if there is any? My assumption is that a neo nazi is someone that supports Nazi beliefs after Hitler died.
|
It's rather simple. "Neo-nazi" is a terms created by political scientist who thought nazism couldn't exist without hitler, and where a bit dissapointed.
| 3 |
87xk1i
|
Culture
|
Why is Easter typically represented by a Bunny giving eggs? Whats the connection of a Rabbit to Christianity?
|
Christianity had a habit of incorporating pagan symbolism in an effort to convert those people to Christianity. So, it was a little bit of heresy for the greater good. God understands.
| 2 |
ejr5av
|
Biology
|
If we move because of electrical impulses, how and where is the first impulse generated? I learned that our heartbeat is controlled by a node that depolarizes because it's unstable, leading to other depolarizations, and contractions of the heart. I also learned that voluntary movement requires depolarization, starting in the brain. Where does the initial depolarization for voluntary movement start? What makes this depolarize? I know I have to think about and plan an action before I carry it out, but how does "thinking" get the electrical impulse started? In fact, what starts the impulse that creates "thinking" itself?
|
The ion pumps in your nerves will generate action potentials (voltage differentials across a membrane) that are occasionally strong enough to cause neurons to fire without external stimuli.
| 2 |
94chq3
|
Other
|
why do many young children walk around in their heels raised off the ground I see it all the time at the mall and places where kids aged like 4-10 congregate. They just stand on their toes and walk. Why? Is this a psychological thing or is it like training muscles or something? Our oldest is 5 and I've never seen her to this yet. It seems most prevent around 8 or 9 I think. Edit: some googling triumphs over eli5 on this one. Apparently what I'm observing is called "idiopathic toe walking" and we don't really know why it happens, but it may be an early sign of ADHD, autism, and a bunch of other stuff. The kids I commonly notice it with haven't appeared outwardly to have a mental condition (but I also wouldn't be surprised if it were solidly linked to adhd.) There's another non idiopathic category that we know is caused by cerebral palsy apparently too.
|
I still do that sometimes. I feel like it's because I'm paranoid about the ground being dirty or too cold
| 6 |
6zlq41
|
Repost
|
Why do Helicopters work?
|
The rotor is not just flat blades spinning through air, they're angled like a propeller or fan. With large enough blades moving fast enough, that gives you lift. That, of course, just gets you off the ground. There's a fairly complex machinery inside the rotor that makes the blades change their angle ("pitch") as they rotate, giving you control over the craft.
| 3 |
93aohm
|
Physics
|
can someone explain Dr. Hawking's concept of "Imaginary Time" like I'm 5? What does it exactly mean in laymen's terms?
|
Oh boy, this is a tough one to ELI5, but I'll try. Without getting into too much detail, the important part of general relativity is what is known as a metric tensor (the name is kinda intimidating, but try not to worry about it). Basically, this is the thing that gives you all of the information about your spacetime. However, the only difference between a space dimension and a time dimension is a negative sign (so the time term gets a negative and the space term gets a positive or vice versa depending on convention). It also turns out that, usually, these terms are all squared. So, if you multiply the time term by the square root of -1, you get back a space term. But the square root of -1 is an "imaginary" number, hence the name imaginary time. But what's the point of it? Well there are a lot of thermodynamic implications of imaginary time, but I think you are more asking about the big bang type of deal. Essentially, what Hawking (and others with him) found is that, by considering imaginary time and using it with standard time, you can "cap off" certain types of universe. Basically, at early times, you can consider time to be imaginary and therefore act more like space. What this does is actually closes up the boundary of the spacetime so that it looks like it is all originating from one point. It gives you a big bang. This is known as a Hartle-Hawking state and has actually been a very valuable tool for understanding quantum gravity.
| 9 |
5sy5nk
|
Technology
|
Why does the iPhone require a passcode after restart if the fingerprint scanner is secure?
|
Because you need a warrant for the password, and cops can scan your finger onto your phone as legally as they can your finger onto a finger print card. TLDR: turn off your iPhone if ever arrested. Edit: in the US anyway.
| 3 |
62y5na
|
Other
|
Why are coathangers used in illegale abortions, and what harm does it do to the body?
|
Coat hangers have been used by women to try to hook the fetus and drag it out. The inserted device can easily puncture the cervix and cause infection, or simply be unremovable without surgery. This makes self-induced abortion via this method a very dangerous procedure. Pro-choice advocates often argue that if a woman is desperate enough to risk death for an abortion, it makes little sense to withhold a safe abortion from her. Many have claimed that actual coat hangers have never been used for attempted abortions. This is false. Knitting needles, bike spokes and umbrella wire have also been reportedly used.
| 3 |
7b12l6
|
Other
|
How do individuals and companies void taxation by putting their money in the Cayman Islands?
|
In part by breaking the law. The Cayman Islands have pretty strict finance privacy laws, so it is difficult for law enforcement to trace money once it makes it to a Cayman bank. Let's say I want to buy a house from you. I could pay from my US bank from your US, but that money would be completely traceable and you would have to be honest when you reported that income as a capital gain. But if we both use Cayman banks, you can pretty much tell the IRS whatever you want, even that you took a loss on the house and deserve a deduction. It is illegal, but there is little to be done to prevent it. The only downside is that your money is kind of stuck in a Cayman bank, and it can be hard to get it back into the US. But if you do business with a lot of people who also have Cayman banks, it is less of a big deal.
| 1 |
6t45c2
|
Biology
|
What makes my brain go "I don't know how to do this therefore I don't want to do it"?
|
Noob here but I'm 99% sure it's the same part of your brain that is responsible for fear. We fear the unknown because of it's inherant risk. Therefore lack of experience can be enough to scare us away from new pursuits.
| 2 |
5xepq4
|
Biology
|
What causes an Existential Crisis to trigger in our brain?
|
The realization of death, and the questioning of our purpose and actions in life, which gets ever shorter.
| 42 |
6p50ig
|
Chemistry
|
Why do pancakes/pop tarts smoke in the microwave after only 1 minute? This has happened to me on multiple occasions and i'd like some answers. (Curious)
|
Pop tarts don't belong in there for a minute. At most, 15 seconds. You are delivering too much energy into something that can't take it and will start igniting bits of the food.
| 2 |
5ll6g5
|
Other
|
In a box of tissue paper, how does the next piece of tissue come out when you pull out the one above it?
|
Some fairly clever origami. Each tissue in the box is folded both to fit better in the box and to have a little flap that connects to the next tissue. When you grab the top tissue, the next tissue starts to come too. Eventually the friction force holding the next tissue to the tissue that you are pulling is smaller than the friction force of it being dragged through the opening. When this happens, the next tissue stops partway out of the box and separates from the tissue that you are pulling, leaving one tissue in your hand and the next tissue poking out of the box for convenient grabbing.
| 1 |
6lyfg1
|
Biology
|
What happens in our brain that makes it seem like time is slowing down during intense situations?
|
Adrenaline. Your brain is overclocked and responds faster to stimuli. Time isn't slowed down. But it SEEMS to slow down. Because you're, essentially, experiencing time at a faster rate. Consequently, it's believed that flies experience time faster. Their response time is really small. I think that's due to the physical size of their brain/whatnot leading to small lag-time. The signal just doesn't have as far to travel. I think that also means elephants would then experience time going by slower. But it's a hard thing to study as it's pretty subjective. Maybe they've tested elephants response time? Which is probably about as close you're going to get to measuring how fast time seems to be going for someone. I have no idea how adrenaline does what it does as I suck at chemistry.
| 1 |
c0auxt
|
Economics
|
How are unprofitable companies/services like Hulu worth so much money?
|
Pretty much every business ever starts out unprofitable. It takes time and money to build up to profitability. So when we discuss the value of a company there is more to it than "well are they making money right this second". Hulu has the *potential* to be insanely profitable because once the infrastructure is set up each additional user is virtually all profit. In addition, we need to look at why they aren't profitable. If they aren't profitable because they aren't selling anything that is a problem, but if they aren't profitable because they are investing heavily in growing their business then they might be even more valuable than if they were just collecting cash. In short - because the market thinks that their future value is a lot higher than their present.
| 2 |
ataxb6
|
Biology
|
What was/is Spanish Influenza and why did it kill so many people?
|
Back at the turn of the century (1918-19) when a new type of flu (H1N1) appeared (originally thought to have originated in Spain which is where it got its name). Nobody on the planet had previous exposure to it so nobody had any antibodies/immunity built up to it. More sick people + more people susceptible = even more sick people. Travel was becoming much cheaper/easier so sick people were capable of travelling further and spreading the disease as well. A few more things as well but that's about the ELI5 of it.
| 7 |
f71lle
|
Other
|
How did brothels work before birth control?
|
Barrier methods: copper coins, sponges, condoms made from animal intestines. Douching with strong vinegars or alcohols. Herbal abortificients like yarrow and pennyroyal. Edit: Lots of people asking about the copper coin thing. Copper has some spermicidal properties. They use it to make some IUDs. But seriously, please don't get contraceptive advice from this thread. Talk to a doctor. And please don't start shoving strange things in your vaginal canal. The lives of old-timey prostitutes were short and painful for many reasons. Lack of sanitary birth control was absolutely one of those reasons.
| 32 |
6i881n
|
Biology
|
Went on vacation. Fridge died while I was gone. Came back to a freezer full of maggots. How do maggots get into a place like a freezer that's sealed air tight?
|
They didn't "get in" exactly. The horrible truth is you've probably never taken a bite of food that WASN'T adulterated by bug eggs. They're in EVERYTHING and can withstand crazy bad environmental conditions until the right circumstances come about to hatch. The eggs those maggots hatched from got there when the food was still alive or during processing. Enjoy your dinner!
| 28 |
c8mlxn
|
Physics
|
What would be the real dangers of putting water on a nuclear meltdown? So I watched Chernobyl and they had some nice ELI5 moments in the show but what confused me was the part where the water tanks were full and they said that if the fuel hit the water tank then it would explode again. So I tried Googling it and found some articles that says it wouldn't have exploded and the show got it wrong. So what I'm wondering is if the scientists weren't worried about it exploding then why was it such a huge deal to drain the water tanks? Especially since they state several times that water cools the fuel.
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in the show they mention another explosion. While this isn’t physically possible to the degree the show expresses, in 1986 they didn’t know that. Superheated fuel hitting water can cause a lot of rapid steam and hydrogen generation and can cause a steam release. However no explosion. You have to put water on the fuel to stop a core melt in most cases. The question is usually, how much. If you put too little water on you just make more steam and hydrogen without actually cooling the fuel and risk a hydrogen explosion (see Fukushima). If you put too much on you make more heavily contaminated water and risk making a big mess of things. The goal we have for boiling water reactors is to use around 3000-5000 gallons per minute to quench the fuel. This is high enough to cool it down even though it’s going to have chemical reactions to this, and low enough to not flood out your containment vent paths and create more of a challenge than necessary. Once the core mass is quenched you drop down to only injecting the minimum debris retention injection rate, which is the lowest amount of water required to prevent melting through the reactor or containment (typically by the time you get here it’s 200 gpm or less). The unknown fears the engineers and scientists had in 1986 were that you might cause the reactor to become critical again and explode, or you might have a large hydrogen explosion, which not only would be a big mess on site but might also impact the other 3 reactors on site and possibly turn it into a multi reactor accident. The reality is that a melted core mass does not have the geometry and proper moderation to become critical again, and the hydrogen would be a challenge but would not be megaton level.
| 2 |
kvgqdp
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Technology
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Why are Cpus so tiny compared to a gpu? Would it not make more sense to make a fist sized cpu so manufacturers don't have to figure out ways to pack more into each generation they can just use the space?
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> Why are Cpus so tiny compared to a gpu They aren't. [This]( URL_0 ), strictly speaking, is not the GPU. We tend to call it the GPU, but it's not. The actual GPU is [a little chip]( URL_1 ) on the circuit board inside that thing. Everything else is the stuff that supports the GPU: memory, capacitors, voltage regulators, that sort of thing.
| 3 |
azuy7e
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Physics
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How is it that things such as Centrifugal Force are obviously real and can be felt in normal everyday life, but yet isn’t classified as a real force in Physics?
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It has everything to do with the reference frame of an observer. Calling something a "fictitious force" is actually a misnomer: the proper term is "inertial force," which means that the observer is in an accelerating reference frame. The force is called "fictitious" because, in a stationary rest frame, the force doesn't act on the observer, as opposed to, say, gravity, which will act on you whether or not you're standing still or accelerating. & #x200B; Consider a situation in which you're on a ship that's moving at a constant speed; it's not accelerating. If you drop a rock from the top of the mast to the deck, the rock is going to fall in a straight line and land right next to the mast. This is a stationary reference frame. Now, assume that the ship is accelerating. If you drop the rock from the mast, the rock is going to land some distance away from the mast. In order to figure out where the rock will land, you can pretend that the ship is still in a stationary frame. From the rock's point of view (its reference frame), it "feels" a force pulling it into a curved trajectory. But a stationary observer doesn't feel the force acting on the rock, so the force is "fictitious." & #x200B; Now consider a rock being spun around on a string. From the rock's reference frame, it feels a force pulling it outwards: the centrifugal, inertial force, which acts away from the center. While the rock is being spun, it's in an accelerating reference frame. But say you let go of the string. The centrifugal force is called fictitious because the rock doesn't continue moving around in a circle: it's going to fly off tangentially, in a straight line. While the rock was being spun, the centrifugal force was indeed pulling it in a circle, but it becomes fictitious once the angular acceleration is no longer being applied. Hope this helps!
| 2 |
h9txzc
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Other
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Why are there so many ticks these days?
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I live in Florida. I've had to remove two ticks from my body on separate occasions, during my childhood. One on the crown of my head and the other in my left arm pit. I would imagine changes in climate have something to do with a northern migration. Ticks need a warm body to survive.
| 12 |
bg55s6
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Biology
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Being a marine animal, why haven’t dugongs developed the ability to breathe underwater?
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Being able to breath underwater would require almost a complete "redesign" of the mammalian respiratory structure. And evolution doesn't seek to maximize theoretical fitness, it's just a tendency for populations to slowly drift towards higher fitness. Is it theoretically possible for marine mammals to develop the ability to breathe underwater over many millions of years? Yes. But right now, breathing air works well, even for completely aquatic species like whales, so it seems unlikely that it would change any time "soon"
| 2 |
ikxohy
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Other
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Why is there a minimum age (35 y.o.) to run for US president, but not a maximum age?
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In theory, the 25th Amendment would prevent a president who was unfit for any reason (age, sudden onset of disease, etc.) from continuing in office. Political pressure makes that extremely unlikely to actually be practiced though.
| 10 |
djdg90
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Chemistry
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Why does water make a grease fire bigger?
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Since water and oil don't mix, when you dump water on a grease fire, it sinks right through to the bottom of the pan and evaporates instantly, causing the flaming oil to splash everywhere
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