You have three bags of gold coins and 1 penny.

You know that in two of the bags contains real gold but the other containts "Fools Gold".

In the bags with real gold, each coin weighs exactly one pound.
In the bag with "Fools Gold", each coin weighs exactly one pound and one ounce.

You have one penny for a penny scale. How would you determine which bag contains the "Fools Gold"?