In part E, you’ll use your answers from parts B, C, and D to find the average density of each type of penny. Recall that density is mass divided by volume:

D = m/v.

Question 1

Calculate the average density of a penny (in g/mL) made before 1982. Show your work.

Question 2

Now calculate and record the average density of a penny (in g/mL) made after 1982. Show your work.

Part F

Analyze the previous results by answering these questions.

Question 1

Do the pennies from the two time periods have the same volume? Do they have the same mass? Give evidence for your answers.

Question 2

Compare the densities of the two groups of pennies. What do you think caused them to have different densities?

Question 3

Study the densities of the metals in the table below. Based on your experimental data, which metal was likely used to make the pre-1982 pennies? Describe what led you to this conclusion.

Metal Density (g/mL)
Aluminum 2.70
Titanium 4.50
Zinc 7.14
Iron 7.87
Copper 8.92
Silver / Gold 10.46 / 19.3
Lead 11.34

Question 4

Based on your experimental data, which metal was likely used to make pennies after 1982?

Question 5

The actual density of pennies made before 1982 is about 8.8 g/mL. The actual density of pennies made after 1982 is about 7.2 g/mL. Compare your results with these accepted values. What could you have done differently to obtain results closer to the accepted values?