Whats the difference between earlier pennies and later pennies?

Answer 1

older pennies contain more copper, a valuable metal. Newer pennies still contain metals worth more than 1 cent but not as much as older pennies. Wheat pennies are an example. They were minted from 1909-1958 and are made of 95% copper. One exception is the steel penny, minted in 1943 to reserve copper for ammo in World War 2.

Answer 2

Pre-decimal British Pennies were a large bronze coin weighing 9.396 grams and were 30.8mm in diameter and, considering their value, were relatively expensive to produce.

At Britains changeover to decimal currency in 1971, a smaller and therefore cheaper to produce coin was designed.

The New Penny was still made from bronze, but was only a fraction of the size of its predecessor, weighing 3.56 grams and was 20.32mm in diameter.

To further reduce production costs of the Penny (and the Two Pence), from 1992 the Royal Mint reissued the Penny now made from copper plated steel.

The copper plated steel Penny is almost identical to the bronze Penny, but about 1mm thicker, and a little more durable.