Possibly a dumb question, but my school / parents never taught about discharge. I actually spent years thinking I was broken because I didn't know what it was.

Obviously I know it's normal now and it changes throughout my cycle, but I don't think anyone ever explained to me why our bodies make it in the first place.

Is it basically the vagina cleaning itself? Does it have something to do with ovulation? ELI5

Rear view windows have a tab you can pull down for night driving. When you pull this tab, the rear view window changes its angle a precise amount. At one angle it shows the roadway behind you, at the other angle the roadway is much darker, and therefore headlights behind you aren't as bright. However, you couldn't see the roadway to back up at the darker angle.

My question is, how do these mirrors work? The mirrors look like any other mirror in daytime mode. You don't see anything odd from it being able to reflect at a different angle. I don't understand it.

I hope I explained this well enough... Thanks.

what exactly is happening that makes them shake?

I've always wondered about this. If I'm driving 60 mph instead of 80 mph, I'm obviously going slower, but I'm also spending more time on the road. So why does driving faster end up burning so much more gas, even though you reach your destination sooner?I know wind resistance has something to do with it, but can someone explain how that actually works in simple terms?

I get the difference between kilo and mini but why is one in Amps and other in Watts?

Is a single photon just the smallest possible wave of light in an EM field? And how did we discover that size?

So photons don't have mass and don't "take up space" in the sense that unlimited photons can be in the same space, but they can still be measured to have a "size"?

Is this like if I took a tape measure to a ghost, I could say it is 5' tall, but the ghost doesn't actually take up space( like it can go through me)?

I understand how a sheet can feel cool when you first touch it, but I’m confused about whether bedding can actually lower body temperature in any meaningful way. Is the feeling mostly caused by heat moving away from your skin faster for a short time, while room temperature and airflow still determine what happens later? I’m also wondering how moisture changes the feeling, since a fabric could feel comfortable when dry but different after several hours of sleep. Could someone explain the difference between initial coolness, heat transfer, breathability, and actual body-temperature regulation in simple terms? I’m asking how it works, not looking for a product recommendation.

Capoeira has a colored belt system, much like all the other martial arts, only they're ropes. The thing I don't get is it seems like the highest you can achieve is white? So it's backwards? No, it also starts at white? What's the difference between graduação white and mestre white?

Who creates new words? I read somewhere that when enough people start calling something by a particular word, everyone accepts and follows. Looks ok for nouns like places, animals etc. but...

Let us take English as an example. Words like perseverance, assassination, fulcrum, pendulum etc. require some effort to form for the first time ever and propagate down the line. Words for language foundation required for communication. Who thinks about it and makes it for the first time? Is there any authorization required for a new word to enter a dictionary?

edit: reddit has some real experts with patience to explain things that they already know. This is awesome, I got some very good explanations in the first few answers itself.

The earliest form is said to have started close to 85 million years ago, are the two species just that hardy?

Intuitively, I thought it was light reflects off an object (like you) then reflects off the mirror then hits your eyes and you see it.

But then someone said it was the light just directly reflects off the mirror to then hit your eyes (nothing else like light from the sun hits the mirror then you) but that makes no sense because then you shouldn’t see the objects in front of the mirror in the mirror???

I understand that Q-Max is used to describe how cool a fabric feels on first contact, but I’m still not clear on what the number physically represents. Does a higher value mean heat leaves your skin faster in that first moment of touching the fabric, rather than the sheet staying cooler all night? I’m also trying to understand how two sheets can feel similarly cool at first but feel different later, once body heat, humidity, and the rest of the bedding are involved. Could someone explain the measurement with a simple everyday comparison, without turning it into a product recommendation?

Hi, good morning. I'm uneducated in this discussion. I'm considered doing a Dependant Care FSA, which has a $5000 max per year($192.30/paycheck). This is a "Pre-Tax" Deduction.

I would then, as i understand it, pay the 383/week for Daycare, submit a request for reimbursement, and get that back. How exactly does this actually "save" money?

Secondly as a continuation, same thing for Roth IRA vs 401k?

I drove around 500 kms with my friend. My car has a 1.6 engine; his has a 1.4. We went together, so roughly the same speed (around 110 km/h most of the time).

In that distance, my car consumed more gas than his (let's say, for example, 6 litres).

If that gas is not converted into speed, then what is it being used for? Heat? The engine is heavier, so it needs more gas to move it?

Thanks, and sorry for any mistake in my English.

I have seen magicians give a Rubik's Cube to a random audience member while keeping one for themselves. The audience member randomly scrambles their cube, and so does the magician. At the end, the patterns on both the audience member's cube and the magician's cube are exactly the same. How is this done?

Basically the title, why do some liquids evaporate slowly even when way below boiling temperature like water and alcohol, but my desk isn't slowly turning liquid?

Bonus question, do all liquids evaporate or is there a specific subset?

What does "hard" here mean? I know that if all NP problems can be reduced to this problem in polynomial time, then this problem is NP-hard. But when you reduce a problem, don't you reduce it to a simple problem so that it's easier to solve 😂 So NP-hard is actually NP-easy?

Happened moments ago with a remote- opened it and switched the 2 AAs' positions and VOILÀ! Realized how often this works with all kinds of devices and started wondering "But... why?" 🤔