According to the U.S. Mint, one penny weighs 2.5 grams, which means 100 pennies weigh 250 grams. That equals 8.81 ounces or a little over half a pound.
As for a diameter, a penny is 3/4 of an inch across, and it is 1.52 mm thick (0.06 of an inch). Though most people think pennies are completely made of copper, they are only covered in copper; they are mostly zinc as copper only makes up 2.5 percent of the penny. The U.S. penny has been minted in some form since 1793. Other coins never made it past the end of the 19th century, including the half-cent, the two-cent, and both the silver and nickel three-cent coins. In fact, one coin, the 20-cent piece, was only manufactured from 1875 to 1878.