If a drug's half-life is, say, 3 hours, 1/2 the dose is gone in 3 hours, and then half of what's left (so, 1/4 of the original dose) is gone in another 3 hours (meaning 3/4 has cleared in 2 half-lives, or 6 hours), etc.

Is that a physics half-life? I was (am) a dummy when it comes to physics.

That is a physics half-life. Why does it work like that? I don't understand why it works like that in physics, either. To me it indicates the molecules are talking to each other. "Okay, me and Jorge are outta here. That's half of us gone. The rest of youse guyz, you got 3 hours to clear exactly half of youse outta here. Draw straws or something. Talk amongst yerselves."

I've been in a crowd at open mic night that exited the building in exactly that manner.

Spooky.

The cancellation of debt document says 2013.

But, if you don't get the money until 2014, shouldn't it count as 2014 income? Taxes are confusing.

Exponential decay! It's like compound interest in reverse.

Explain to me how the particles know there's half of them left and they should slow down decay by half! There's a subatomic messaging service. It's weird, dammit.

It's just a simplified way of describing the rate of decay. You can also do it with one of those equations that have a lot of squiggles in them.

The debt cancellation is dated 2013, therefore that's counted as income. The lease payment isn't officially mine till the check gets here in 2014. Fortunately I don't have to pay the taxes on that till next year, cue the interest bearing account I don't touch for a year.

Suppose you have a hundred dice. You roll them all and any that come up one disappear. You'll lose a sixth of them every time you roll, right? That's pretty much my understanding of radioactive decay on an atomic level, though of course the dice aren't six-sided. They point is, they don't have to know the state of any other dice, each just has to know it's own state.