Brainteasers that I managed to solve - 2

I got this wrong the first time but I figured out how to solve it given the correct answer:

There are 8 billiard balls of the same size. One of them is slightly heavier than the rest. You are given a classical two-pan balance. What is the minimum number of time you need to put the balls onto the balance to tell which ball is heavier.


The answer is:

Two
Take any 6 of the 8 balls and split them into two groups of 3. Place each group of the balls onto each side of the balance. If they weigh the same, the heavier ball is one of the two left behind. If one of the groups is heavier, put any two of the 3 onto each side of the balance. It will tell you either one of the two is heavier, or if they weigh the same, the one left behind is the heavier one.