Prior to 1982, pennies should have a density of 8.96 g/cm3, which is almost the same as pure copper. After 1982, pennies should have a density of 7.14 g/cm3, which is almost the same as pure zinc.
Pennies minted prior to 1982 in the United States were predominantly composed of copper.
The density of copper is approximately 8.96 g/cm³. This similarity in density indicates that the pre-1982 pennies were likely made from nearly pure copper.
The uniformity in composition during this period was integral to maintaining the intrinsic value of the coin.
Conversely, post-1982 pennies underwent a significant change in composition due to rising copper prices.
To reduce production costs, the U.S. Mint transitioned to a zinc core with a thin copper coating.
The density of zinc is approximately 7.14 g/cm³. This alteration aimed to preserve the visual and tactile characteristics of the penny while utilizing a less expensive material.
In a well-conducted experiment, the measured average mass and deviation of pre-1982 copper pennies and post-1982 zinc pennies should align with the respective densities.
If the data deviates significantly, it may suggest variations in the penny composition or experimental errors.
The correlation between expected and measured densities provides valuable insights into the consistency of coin production and the economic considerations influencing material choices in minting.
Question
what was the average mass and deviation of the copper pennies (pre- 1982) and zinc pennies (post-1983)? Is the difference in the average mass greater than the deviation? What does the difference in mass tell you about the relative density of copper versus zinc?