In Hot Water

Okay, this post will convince you that I am either brilliant or a moron...Anyway, the other day I started wondering: Why is it that when you increase the amount of cold water coming out of a faucet, the hot water no longer hurts? (I.e. if you're washing your hands and you originally have too much hot, you don't need to reduce the amount of hot water to stop the pain, you just need to increase the flow of cold water.)

What is heat, after all? It's random movement of molecules. So at first glance, it's not immediately clear why the addition of cold water will mitigate the damage caused by these rapidly vibrating molecules. Think about it like this: If somebody is throwing knives at you, you don't eliminate the danger by having someone stand right next to him and toss water balloons too.

I'm pretty sure I've figured out the solution, but I'll leave it to the class as an exercise.