QUESTION: How does the mint date of a U.S. penny affect its density?

VARIABLES MV: Mint date of penny RV: Density of penny CV: All pennies are U.S. currency CV: Pennies are in moderate condition CV: Standard currency, not special edition or collectible

HYPOTHESIS If the penny has an older mint date, then the penny will have a lower density than a newer penny because the older penny will most likely only have one type of metal in it instead of several.

PROCEDURE Materials: Nine to ten U.S. pennies, one per decade One graduated cylinder and one scale Beaker of water, about 80 mL Steps: 1.Sort out pennies oldest to newest 2.Fill cylinder, make mental note of water amount 3.Place oldest penny into water and record water displacement 4.Repeat steps 2 and 3 with all pennies 5.Place the oldest penny on the scale and record mass 6.Repeat step 5 with all pennies and calculate density

DIAGRAM Items not to scale

DATA TABLE

CONCLUSION In conclusion, if the mint date of a penny is older than a newer penny, it will have a lower density than the older penny. I reached this conclusion by measuring the densities of nine pennies. The oldest penny (1902) had a density of 3.1 grams per milliliter while the newest penny (2003) had a density of 5 grams per milliliter. My hypothesis was correct, in which I stated that an older penny would have a lower density. There's a difference of 1.9 grams per milliliter between the two densities. The highest density was 6.2 grams per milliliter, which both the 1953 penny and 1973 penny had. The lowest density was 3.1 grams per milliliter which the 1902, 1935, and 1964 pennies had. There's a difference of 3.1 grams per milliliter between the two densities. Finally, an older penny will generally have a lower density than a newer one, based on my findings.

WHY ITS IMPORTANT Pennies are a coin that are used every day in every state of America. Pennies are generally associated with copper, however most modern day pennies are made of copper plated zinc.