- form 3 groups of 4 balls each
- First weighing:Pick any 2 groups and weigh them they will balance or not, if they balance then the heavy ball is in the 3rd group, if they don't balance then you have identified the group of 4 that contain the heavier ball.
- Second weighing: make 2 groups of 2 balls and weigh them on the balance. One side will be heavier choose those 2 balls
- Third weighing:weigh the 2 balls on the balance one side will be heavier that side is the odd ball.

Jim