Coin Weighing

The purpose of this game is to find out a fake coin by using a scale. There's is only one fake coin in the pile of coins and the fake coins is either heavier or lighter than the real ones but you do not know whether it is heavier or lighter. You can use the scale only a few times depending on the number of coins in the scale. In the end you have to tell which coin is fake and whether it is lighter or heavier than the real ones.