In spite of the new lighter total coin weight of 2.5 grams each, these newer coins are identical in diameter and thickness, and nearly in appearance, to the mostly copper (95%) cents issued before mid-1982, which weighed 3.11 grams each. A few pennies were struck by error in brass dated 1983 and are extremely rare.
When did pennies get lighter?
1982
The change from copper to zinc took place in 1982. The mint was also experimenting with the size of the date so there are actually 7 different types of pennies dated 1982. For this reason the heavy pennies in the exercise will be dated 1980-82. The lighter pennies will be from 1982-85.
Why are pennies before 1982 heavier?
Upon changing the composite from solid copper to the zinc and copper alloy, so to did the weigh of the coins themselves. Prior to 1982, a penny made completely of copper was significantly heavier than the zinc and copper alloy counterparts.
When did the composition of the US penny change?
However, in 1982, the United States Treasury anticipated an increase in the price of copper, which opened the door for a new coin composition. The once solid copper coin is now comprised of a solid zinc base and coated in a copper alloy.
How does the mass of a penny change?
The mass of a penny has changed significantly whenever the metals that make up the penny have been changed. Different metals change the mass of a penny because they have different densities. While pennies were made of pure copper until 1837, but switched to bronze for a few years until 1857, when it was returned to copper.
What was the mass of a penny before 1982?
Before 1982, pennies were 95% copper and 5% zinc. Then after 1982, the compostion was 97.6% zinc, and 2.4% copper. So this means that the pennies made before 1982 will have a different mass from those made after 1982. In a modern physics textbook, the mass of a penny was used as part of a word problem.
What was the mass of a penny before World War 2?
Mass of a Penny. The composition of the penny was pure copper from 1793 to 1837. Then following that, it was made of bronze, and in 1857, it was made out of copper. In 1943, the content of the coin was changed to zinc coated steel because of the copper shortage during World War II. Before 1982, pennies were 95% copper and 5% zinc.
