Recent comments in /f/explainlikeimfive

Sloloem t1_iydwukt wrote

GOTO would work fine in a single threaded environment, you can't use it in javascript just because javascript doesn't have a GOTO statement. If it did it would probably look the same as it does anywhere that does have it where you pair GOTO some_label with a line of code reading :some_label to give the GOTO a target line. Not sure why they didn't include it.

1

Moskau50 t1_iydwi3f wrote

Insulin regulates blood sugar levels. It tells cells to start pulling glucose out of the bloodstream for storage as glycogen or as fat. Insulin levels are controlled by the pancreatic system, which helps regulate blood sugar levels.

Insulin resistance is when cells are not as responsive to insulin, so blood sugar levels rise to unhealthy levels. Temporary high blood sugar isn’t a problem, but if it’s sustained, it can lead to significant health problems, like kidney damage/failure and ketoacidosis (which can then lead to heart attacks), among other, more minor symptoms.

1

DecentChanceOfLousy t1_iydvi3w wrote

Yup. Programming languages or technical formulas end up having so many parenthesis that most editors support color coding or matched pair highlighting so you can sort out which is which. And you'd need more if every operation had to have parenthesis around it to clarify which order it's supposed to be done in. If you kept the left-to-right convention (despite throwing other conventions which are no more arbitrary away), you could reorder some things to remove a bit of the confusion. But it wouldn't help nearly as much as every symbol having an order of operations so you skip as many parenthesis as possible while remaining unambiguous.

1

Drops-of-Q t1_iydvhr8 wrote

Sound is simply vibrating air. These vibrations propagate as waves. The higher the frequency of that vibration, the higher the pitch of the sound, but the shorter the wavelengths.

The vibrations here are caused by the splashing of the water. These vibrations have tons of different pitches, but when you have air vibrating in an enclosed space the sound waves reverberate within that space which amplifies certain pitches, namely the ones with wavelengths that match the size of the space. As the space for the air to resonate gets smaller, the shorter the wavelengths are that get amplified.

This is exactly how brass instruments work. When you move the slide of a trombone out the tube gets longer so you get a longer wavelength and thus a lower note.

That's the basic explanation, but here is a more advanced explanation of why the wavelength is dependant on the space it can vibrate in, even when it has an open end as a glass has. Many differently shaped rooms have different effects on timbre and pitch. When we talk about this we tend to simplify it by talking about a tube that is open in one end, which conveniently is exactly what most glasses are.

The bottom of the glass is where the air vibrates the least freely, so here it forms what's called a node. You can imagine it as the ends of a jumping rope that barely move, while the center where there is most movement, is what's called the antinode.

If the tube of air were sealed in both ends there would be a node in both ends and an antinode (or several) in the middle just like the jumping rope, but when the tube is open in one and there will always be an antinode in that end where the air can vibrate the most freely.

The fundamental pitch of a tube is the biggest wavelength that can "fit" in it. For a tube that's sealed in both ends that is simply a wavelength the exact length of the tube, but for a tube that's open in one end the fundamental wavelength is twice the length. That's because you have an antinode in one end so it's almost as if only "half the sound wave" is inside the tube.

For a closed tube, the overtones of the fundamental simply have 1/2, 1/3, 1/4, 1/5 etc. the wavelength, because you'll always have a node in either end, but you can have more nodes and antinodes throughout the tube. But for a tube with an open end they are 1/1.5, 1/2.5, 1/3.5 etc. because you'll always have an antinode in one end.

2

Bacon003 t1_iydt794 wrote

You used to be able to use a scanner to listen to cell phone conversations decades ago before they were encrypted. It was actually kinda fascinating. The type of 850 mhz band scanner you needed was on the more expensive side at the time, but was still the sort of thing you could by at Radio Shack.

I have a pet theory that there's probably a few people who got rich using insider information they gleaned from picking up conversations in the Wall Street area that the participants thought were confidential.

1

explainlikeimfive-ModTeam t1_iydt1ll wrote

Please read this entire message


Your comment has been removed for the following reason(s):

  • ELI5 does not allow guessing.

Although we recognize many guesses are made in good faith, if you aren’t sure how to explain please don't just guess. The entire comment should not be an educated guess, but if you have an educated guess about a portion of the topic please make it explicitly clear that you do not know absolutely, and clarify which parts of the explanation you're sure of (Rule 8).


If you would like this removal reviewed, please read the detailed rules first. **If you believe it was removed erroneously, explain why using this form and we will review your submission.

1

pinkplacentasurprise t1_iydsz8q wrote

Think of a guitar string. If you play a note and then slide your finger up the frets, the pitch gets higher as the string gets shorter.

Same thing is happening in the glass. The sound you’re hearing is the air in the cup vibrating and resonating. As it fills, that column of air gets smaller and smaller, like a trombone player pulling the slide in.

As the air column gets smaller, the length of the sound waves gets shorter too which results in a higher pitch.

1

stairway2evan t1_iydss2f wrote

The Earth is dong two types of movement in space - it's rotating on its axis, and it's revolving around the sun. Rotating on its axis gives us day and night - because sometimes we're facing the sun, and sometimes we're not. Revolving around the sun gives us our seasons, because of the Earth's tilt relative to the axis of the sun.

But here's the thing - those two movements don't quite match up. It would be really cool if they did, but they're just a little off. So today is November 30th, and it would be awesome if next year on this day (Nov 30, 2023), the Earth was in the exact same place relative to the sun. But it's not - it's about a quarter of a day behind. It's not a big difference, but over the years, that difference will add up. We're used to the winter solstice being around December 21, for example, but if we didn't adjust our calendar, it would start creeping up sooner and sooner. Which isn't a bad thing, but we're creatures of habit, and it's nice to have these things be more consistent.

So for consistency, we just mess with our calendar so that the year's movement and the day's rotations keep on track with each other. That maths out to roughly one day added every 4 years to keep us on track - we also skip leap years every century (except every 4th century) to keep that on track even closer to the true value. It's just a necessity because our day measurements and our year measurements don't exactly correspond with each other as neatly as we'd like.

3

_Connor t1_iydsrh0 wrote

Shares aren’t necessarily synonymous with voting shares nor is there necessarily a 1:1 vote to share ratio. Someone can hold 75% of the total equity in a company but if someone else owns preferred shares that give them 1000 votes per share, then that person will have more voting power than the person who owns 75% of the company. In that case then yes, the person with the voting super majority could fire the person who has 75% of the total equity.

Elizabeth Holmes owned 51% of the equity in Theranos but her voting power was pretty much 100% because her class of shares gave 100 votes per share whereas everyone else's only gave them 1 vote.

It all depends on share structure.

1

wjbc t1_iydsfa9 wrote

The Earth takes a few minutes less than 365-1/4 days (365.24219) to go completely around the Sun. Once every four years we add a day to the Gregorian calendar — February 29 — to make up for most of this difference. That’s a leap year.

However, because the difference is a few minutes short of 1/4 day, any year that is evenly divided by 100 would not be a leap year unless it is evenly divided by 400. Thus 1600, 2000, and 2400 are leap years, but 1700, 1800, 1900, 2100, 2200, and 2300 are common years, even though they are all divisible by 4.

1

MagicalPizza21 t1_iyds4jg wrote

A leap year is a year that has an extra day. This extra day is added at the end of February: February 29th. It's added every four years because Earth does not actually take exactly 365 days to orbit the Sun, but closer to 365 1/4 days. If not for leap years, we'd gradually shift our calendar relative to Earth's orbit.

1

BurnItNow t1_iyds2oh wrote

Think of it like a rubber band. When the glass is empty the rubber band is loose. If you pluck the rubber band it will give you a low pitched “boioioing”

As you tighten the tension on the rubber band it gets higher pitch and less boioioioing and more “boing boing bing bing bin bin” tighter rubber band- higher pitch- less vibration.

Same thing but with the cup being the rubber band. As the water fills there is less cup to vibrate.

0

mydoglikesbroccoli t1_iydrot7 wrote

You have good answers above, but one thing I didn't see is a mention that how much something will dissolve in hot water and how fast it dissolves in hot water are two different things. They usually go together, but not always.

Most, but not all, things will dissolve more in hot water than cold. It's tough to explain why that is in li5, but has to do with the universe liking it when things can move around more (we call this higher entropy), and that's what happens when most things dissolve in water- they get to float around and mix. When things are hotter the universe apparently likes it even more when things can move around more, so more stuff dissolves. There are some things that dissolve even less in hot water because the water has to organize or be shaped a certain way to get the thing to dissolve (the water is inconvenienced and can't move around as much), but that doesn't happen too often. I don't know why the universe likes it when things move around more, and likes it even more at higher temperature, but that's what a math equation called the Gibbs Free Energy equation tells us, and it seems to work.

But with washing hands what may be more important is that anything that's going to happen in water will happen faster when it's hot. I think this is always true- apparently water even freezes faster when it's warmer, as long as it's still cold enough to freeze. As others have explained above this is because the water (is "water molecules" acceptable for ELI5?) is moving around faster when it's hot, and a hotter temperature is very much like having a fast forward setting on, and cold water like being in slow motion. Your hands would probably wash ok in cold water, but it'd take longer (unless youre using one of those soaps that's made to work best in colder or room temperature water).

Another effect is that hot water is a little bit thinner and sticks to itself less than cold water, but that's probably not the main reason it cleans better. It should help dirt and germs get "wet" and start to loosen up a little bit faster though.

1