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?
