Put 6 balls on each side. One side will be heavier.

Take the 6 balls from the heavier side, split them into 3 each, and put them on different sides. One side will be heavier.

With the 3 balls from the heaiver side remaining, take TWO, put 1 on each side. If one side/ball is heavier, then that's the one. If they both weigh the same, then the third ball is the heavier one.



Give me another one, I'm bored at work