This resulted in the steel mixing with the copper for the first few pennies produced that year. No one noticed the error, and the pennies entered circulation. The US Mint estimates that 40 of them ...

During World War II, the U.S. Mint switched to zinc-coated steel pennies to conserve copper for military use. However, a small number of 1943 pennies were mistakenly struck in copper ...

Re “So long, penny! Trump orders U.S. to ditch 1-cent coin after decades of complaints” (Feb. 10): Consider this solution to the penny problem. In 1943, copper became so dear that to ...

A copper penny is heated and suspended above the surface of acetone in a beaker. The copper demonstrates heterogenous catalysis in the combustion of acetone to carbon dioxide and water. This exotherm ...

A copper penny appears to turn to silver after heating in an evaporating dish with a mixture. The penny then appears to turn to gold when heated in a flame. Heat causes a fusion of zinc and copper to ...

In the early 1940s, the U.S. used zinc-coated steel instead of copper to make pennies because the latter was needed for World War II. Today, wheat pennies are considered the most commonly ...