Bob A. writes: I write instructional stuff for middle school and high school math-science. I’ll write several units about pennies, pre-1982, 1982, and post-1982. My measurements indicate that pennies from 1994 to now are slightly thinner than earlier pennies, but have the same mass. Can you enlighten me? Was there a change in the way pennies are manufactured in 1994?
Not officially. The current cent is minted from zinc with a plating of pure copper. The total content is 97.5% zinc and 2.5% copper, at least that is what it is supposed to be. The United States went off the silver standard in 1964 and subsequently the Assay Commission was abolished. So the body that used to check the specifications of the “coins of the realm” no longer exists. It doesn’t matter since the coins are now essentially tokens and used for convenience only (note that coins are no longer legal tender). Other researchers have also found discrepancies in the weights of current coins. This never would have be tolerated in the days when coins were real money.
