The Hollow Penny

Pennies are made of copper, aren’t they? The outside is certainly made of copper, but that’s not the whole story. Before 1982, pennies contained about 95% copper and 5% zinc. After 1982, however, the composition of pennies was changed to contain mostly zinc and only a small amount of copper. In this activity, the percentage of copper and zinc in post-1982 pennies will be determined.