You should share thin on /r/cinemagraphs as well! Looks amazing.

Both answers aren't right. On a test only one of those is right, and one is wrong. When you write:

1+2x3

That means "multiply two x three, then add one". There is only one right answer to this. It's 7. 9 is wrong.

If what you actually meant was add 1+2, then multiply by 3, than you have to write it as (1+2)x3, and then the only right answer is 9.

The rules we're talking about here are only about how to write the math so that it means what you intend it to mean (like multiply 2 by 3 then add 1, vs add 1+2 then multiply by 3). But for whatever you write, there's only one right answer.

The math itself is fundamental. It would work no matter what convention we chose. The only arbitrary thing we're deciding on here is how to WRITE math so other humans know what you mean when there's more than one possibility.

(more than one possibility for what math you're trying to describe, NOT more than one way that the math itself could go!!!)

It's something we agreed on. Like you pointed out,

1+2x3

would have more than one possible answer unless there was a convention. It would be ambiguous what you actually meant. So people created "order of operations" rules to make it possible to write math without the ambiguous confusion that would happen if there was no agreed convention.

>Why not just set the minimum bid at the lowest price you’d be willing to sell at

Because if the buyers know you'd be willing to sell it for [x low price], there's less reason for them to bid any higher than that.

Even if you get lucky as a seller and there's a bidding war, if all the sellers know you'd be willing to sell for $100, odds are nobody's going to bid $1000. If the "lowest price you'd be willing to sell for at all" is a mystery to the bidders, it encourages higher bids.

https://www.reddit.com/r/Showerthoughts/comments/blgsqe/rubbing_alcohol_is_for_outside_wounds_drinking/

https://www.reddit.com/r/Showerthoughts/comments/bk6ao9/rubbing_alcohol_is_for_outside_wounds_drinking/

https://www.reddit.com/r/Showerthoughts/comments/bbkp5z/rubbing_alcohol_is_for_outside_wounds_and_alcohol/

https://www.reddit.com/r/Showerthoughts/comments/az6h58/rubbing_alcohol_is_for_outside_wounds_but/

https://www.reddit.com/r/Showerthoughts/comments/az3ivt/rubbing_alcohol_is_for_outside_wounds_drinking/

https://www.reddit.com/r/Showerthoughts/comments/aju2fk/rubbing_alcohol_is_for_outside_wounds_drinking/

https://www.reddit.com/r/Showerthoughts/comments/ajq6p2/rubbing_alcohol_is_for_outside_wounds_drinking/

Other people are giving you the right answer - it's about surface area and the gills collapsing. But I feel like that needs a more ELI5 description:

Picture someone with long straight hair going underwater. In water, a fish's gills are like a person's hair behaves under water. It's all spread out in the water and every individual strand is floating freely. There's a lot of hair surface touching the water.

When a fish leaves the water into air, their gills act like wet hair when you get out of the water. It all "collapses" into clumps. The amount of contact between hair strands and the surroundings is a tiny % of what it is under water.

Fish rely on their gills being all spread out and free-floating to have enough surface area to pick up enough oxygen. It's not that gills are unable to extract oxygen from air and can only get it from water. The problem is their physical structure prevents them from touching enough air to keep the fish alive.

When you bring the tiny guy onto the field, it would become obvious what you're about to do. And you only have 3 tries to add up to 10 yards gained. It would be very hard to average over 3 yards of forward progress past the line of scrimmage with the other team fully aware of what's coming and lining all their own big guys up front-and-center to block the flying little person (or interrupt the hammer-throw process, which would take a few seconds to set up after the snap).

When water freezes, all the individual water molecules (which are roughly "V" shaped) click together into a highly structured repeating 3D crystal pattern that looks like this. Note all the waters form hexagons, kind of like a honeycomb - that's why snowflakes are hexagonal and have 6-sided symmetry.

So yes the water does "purify" itself as it crystallizes into solid ice. Basically, the salt molecules don't really fit or snap into this hexagonal pattern very well, so they mostly get left behind as all the waters start clicking together into their big solid scaffold.

Plants are mostly made of cellulose, which is a bunch of sugar molecules linked into a strong chain.

Humans can't digest cellulose. For us, eating grass is just fiber, zero calories.

For herbivores like buffalo and cows, they have multiple stomachs and special enzymes and bacteria that let them break down cellulose into usable sugars. For herbivores, eating grass is like eating bread for humans. It's a form of carbs for them.

The other factor is large herbivores spend hours and hours a day eating like 50 lbs of grass. If you eat 10 loaves of bread a day you'd be 800 lbs in a few years too.

Things need prescriptions when they're potentially dangerous or abusable. Epipens (a bunch of adrenaline in rapid-injection device) are both.

How commonly people need a medicine isn't a factor in whether it's available over the counter or only with prescription.

From the sidebar:

>For recommendations of new artists similar to those you already like, use /r/ifyoulikeblank.

You might get good additional answers there. Good luck!

When you burn rocket fuel, it makes a bunch of hot gas. By pushing all that gas out of a (moveable) nozzle in one direction, it pushes the ship in the opposite direction.

ELI5:

It's like blowing up a balloon and then letting go of the neck. It flies off because every action has an opposite reaction. The balloon squeezes the gas out the neck, which pushes the balloon off in the other direction. This would happen in space with no outside air around the balloon too! We just use rockets instead of huge balloons because rocket fuel is a convenient way to bring up a large volume of solid or liquid fuel in a small space and then turn it into gas to shoot out the nozzle as needed.

Or maybe I'm the weird one! Let's wait and see what others say.

This is not normal. It has never happened to me and I can hardly even imagine what you're talking about. Colors appear exactly the same viewed through both of my eyes, all the time. You may want to get a medical opinion on this.

Plane crashes are rare because when they do happen they're so horrible. Dozens or hundreds of people may die, and millions of dollars in damage could result. So to minimize plane crashes, we've set up a whole system of safely building and flying planes with tons of regulations and years of training for the few people that we let fly planes at all.

In a car crash, only a few people might die, and often just the driver...so we let pretty much everyone drive a car with minimal training. Therefore, quite predictably, there are more car crashes than plane crashes.

But if we wanted to, we could make car crashes just as rare as plane crashes! Getting a drivers license would be limited to a few thousand people, require thousands of hours of training to get, require frequent re-certification, and there'd be nearly no tolerance on having a license ever again after making even a small accident. We do all of the above for pilots, precisely because plane crashes are horrific when they do happen. But for cars that much control is unnecessary vs the smaller risk presented by car crashes.

So, at least for your example and other human-related things, it's kind of self-balancing: The worse a potential outcome is, the more time and money it's worth spending to make that event as rare as possible.

Sugar itself isn't bad for you, TOO MUCH sugar is bad for you.

For like 99.99999% of our evolutionary history, food was scarce and unpredictable. It was practically impossible to find enough calories to eat too much. Therefore, having the trait "whenever you encounter an energy-rich food source, eat as much as you can and turn any excess energy consumed into fat" was a GOOD thing. Any animals that had this trait, including our ancestors, had a survival advantage! If you craved to eat as much high-energy food as you could find, you were more likely to survive a famine, drought, injury, or illness.

On the time scale that evolution creates changes, food becoming cheap and plentiful in the modern age happened extremely recently. It's only been like ~150 years that regular non-rich people could afford enough food that it's easily possible to eat too much. To evolution, that's essentially nothing. That's a single-digit number of generations! Human evolution takes tens of thousands of years or more to produce changes.

So that's the problem: We're all still running a program in our brains that says "eat as much sugar as you can find" because that strategy gave our ancestors a survival advantage for like a billion years, and now it's backfiring for the last hundred years or so and there hasn't been time to change the program yet.

Me too!

What a beast! Always blows my mind seeing Temple, especially from this side, that it can be summited by scrambling with no gear.

Birds have the ability to sense the Earth's magnetic field, giving them a sense called "magnetoreception" that acts like an internal compass. The actual physical mechanism allowing this magnetic perception to function is currently poorly understood, unless this textbook chapter from 2015 is out of date (in which case someone with more relevant knowledge in the field please update us!).

Chapter 8 - Magnetoreception in Birds and Its Use for Long-Distance Migration

As others have said, yes it's due to entropy. But I want to get to the "why" a little more.

It's probability. There are thousands, millions, maybe infinite different tangled states a cord can be in, and exactly one non tangled state. Being tangled is the "natural state" simply because it's by far the most likely state.
Every time you put the cord in your pocket and scrunch it around, you're picking another random configuration. Since "untangled" is vanishingly unlikely when picking randomly from all possible configurations, it "spontaneously" comes out tangled ~every time.

The exact phenomenon you're looking for is Spontaneous Knotting of an Agitated String by the way. Here's the landmark paper on it:

Spontaneous knotting of an agitated string - Raymer and Smith 2007

Math blog explaining the above paper.

Video of Raymer doing a talk on the topic.

Yes it's a case for entropy.

>Their natural state is to be tangled. We impose order on them by making them straight.

Even more than this, the "why" can be explained with probability. There are thousands, millions, maybe infinite different tangled states a cord can be in, and exactly one non tangled state. Being tangled is the "natural state" simply because it's by far the most likely state.

Every time you put the cord in your pocket and scrunch it around, you're picking another random configuration. Since "untangled" is vanishingly unlikely when picking randomly from all possible configurations, it "spontaneously" comes out tangled ~every time.

Yes. "Terminal velocity" is just the fastest something will go in freefall in air, when air resistance cancels out gravity.

It's not some sort of speed limit. You can throw something faster than its terminal velocity by hand. For human bodies, terminal velocity is about 190 mph. So if you've ever flown in an airplane or ridden a bullet train, you've gone faster than your terminal velocity too.