badatmetroid

badatmetroid t1_jegepc3 wrote

There may be one bouncer/bartender/etc who's a dick about it but I'm guessing most would just wish you a happy birthday and not mention the expiration date. If you're going with friends just mention the possibility to them and you should go in first (so they can easily bounce if you get bounced)

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badatmetroid t1_jca10rt wrote

In some sense they do. Ionic chemicals are just things that are attracted together and can pack together to make a solid. They aren't "bonded" like covalent chemicals, they are just attracted. We write NaCl, but really every sodium is just attracted to the six nearest chloride ions. The same principle applies to a statically charged balloon.

But with static electricity the charges involved are much smaller and the particles are bigger. In salt you have single atoms with missing (or extra) electrons. In static electricity the particles are huge (10^17 or so atoms of it's dust) and the charge is much smaller: like hundreds or millions of elections meaning the charge to mass ratio is 10^10 less. (these numbers are of the top of my head, but the principle is correct)

So lower charge + higher mass = weaker bond.

They also aren't consistently sized, so you can't get the consistent packing of particles like in a salt.

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badatmetroid t1_j8uly3e wrote

Since 1973 at least 190 innocent people have been executed. Those are just the one's who could be proven innocent after the fact. If you decrease due process, you increase the number of people who get executed before we can figure out that they were wrongly convicted.

https://deathpenaltyinfo.org/policy-issues/innocence

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badatmetroid t1_j3o46ab wrote

Bullshit. I'm from Salt Lake and I do not believe this. Mormons are obsessed with sugar.

A closer look at the methodology is a self reported google forms survey (uh... massive yikes) and only 1100 respondants (so 20 answers per state).

Seeing as states don't have equal numbers of people and randomness exists, I'm guessing some of these states had <5 respondants.

Also the numbers look nothing like this 56k respondent survey that I found with 2 seconds of googling.

https://www.cdc.gov/pcd/issues/2021/20_0434.htm

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badatmetroid t1_j3c1xpq wrote

They move (on average) at 500m/s but they are bouncing back and forth randomly. On average a molecule moves away from it's starting location at the square root of time. So if it takes 1 us to move 1 um then it takes 4 us to move 2 um, 1e6 us to move 1e3 um and 1e12 us to move 1e6 um (or 1 million seconds to move 1 meter).

I pulled those numbers out of my ass but if you know the root mean velocity (your 500m/s number) and the root mean path (average distance until collision) you can use the two numbers to derive the diffusion coefficient from first principles.

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badatmetroid t1_j3c0ket wrote

This question is deceptively complex. Because random motion is (wait for it) random the molecules move left as much as they move right. The result is that distance the average molecule grows with the square root of time. I'm pulling these number out of my ass, let's say it takes 1 microsecond for the average molecule to move 1 micrometer. How long does 2 micrometers take? Your gut instinct probably says 2 microseconds, but the random back and forth means it doesn't grow linearly.

It would take 4 microseconds to move 2 micrometers (because you doubled the distance and 2 squared is 4). It takes 8 microseconds to move twice as far as that and 16 to move twice as far as that... So to move a millimeter (1000x as far) it takes 1 second (1,000,000 times as long). To move a meter (1e6 micrometers) it takes 1e12 microseconds or 1 million seconds or ~11 days. 2 meters is 44 days, 4 meters is 176 days...

But that's diffusion. You said "stationary body of water" which means diffusion is the only thing acting on it. If only diffusion existed, our sense of smell would take days or even years to detect the fire across the room from us. But if the temperature is different in different parts of the room (like because of a fire or a human), then temperature differences lead to density differences which causes convection. The bulk of mass transport in fluids is caused by convection (wind, currents, etc). You waving your hand in the air is also convection (because your hand creates a pressure difference as it moves)

And just in case my graduated advisor is reading this, there's also migration which is caused by electrical gradients. Migration is relevant in electroplating, batteries, ion channels, and more. But that's like 5 lectures away from what we're talking about now.

Edit: someone in another comment used an actual diffusion coefficient and calculated that it takes years for a molecule to move from one side of a bath tub to the other. It's also worth pointing out that is the mean distance from the source, so half the molecules didn't move that far.

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badatmetroid t1_ivxvrd6 wrote

I think of myself as a member in a larger trend. If I think "my vote doesn't matter" and don't vote then people who think the most like me probably are also thinking the same. If we all do the same then suddenly our lack of voting does matter, and people like me won't get representation in government.

Then I suddenly remember voter turn out by age and realize that I basically just reinvented the age old problem of society being help back because the youth don't vote.

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