Marion Usiak, age 10, of Pittsburgh, Pennsylvania, for his question:

Why does the mint make dimes smaller than nickels?

One would expect a big coin to be worth more than a little one. But coins are made of metals and gold is worth more than silver and silver is worth more than nickel or copper. Most likely the first coins were made to use exact weights of valuable metals for trading. Naturally, a gold coin was worth more than a silver coin of the same size and weight. At one time American dollars and half dollars, quarters and dimes were minted from 90 per cent silver and ten per cent copper. Nickels were minted from nickel and copper. That is how a small silver dime came to be worth two nickels. Silver is worth more than nickel.

Times changed and so did the ingredients used to mint our coins. The amount of silver was reduced and replaced with less expensive alloys. The metal in these coins was less valuable. But by this time we had grown used to them. It was decided to mint them in the same styles. So you can still swap one little dime for two bigger nickels.