Puzzle #3

This one is compliments of some of my college friends. I wasted almost two hours on this one...

You are given 12 balls and a balance. One of the balls is either lighter or heavier than the rest (you don't know which). In three uses of the balance, figure out which is different.

Want a hint?

Think you know the answer? Send me email with your solution. You won't win anything, but if you like I'll add your name to the " List of People With Too Much Free Time".

Kevin Fink's Home Page (http://www.fink.com/Kevin.html)