In 1982 some cents were made of copper plated zinc, other were made of copper. The copper cents weight quite a bit more than the zinc. It's about half of the cents that year were copper, the other half zinc.
BonnieSue, if you don't already have this book, it would be a great help for you because it can give you information about every coin that has been used or produced in the US since colonial times. Just don't place any emphasis on the price guides. http://www.amazon.com/Guide-Book-United-States-Coins/dp/0794843042 Chris
1982 is a fun year to complete. There are the two different compositions from each mint, and then also large and small dates. Its actually a bit of a challenge (time consuming) to find them all in circulation.