Coins and Paper Money
Elements and Compounds
Metal and Alloys

Why would changing the percent composition of a penny from 95 copper to 97.5 zinc make it less massive?

Answer

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Wiki User
10/05/2007

The coins are the same size, but zinc is a less dense metal than copper. That means the new coins' mass will be less (2.5 gm versus 3.11 gm). As an extreme example, aluminum cents were also considered back in the 1970s, but the experimental coins that were struck were so light they'd blow away in even a moderate breeze!

The only way to have the coins weigh the same would be to make the new cents thicker or larger, which would have caused all sorts of problems with vending machines and automated coin counters.