Name:_________________________________________________________Date:___________________Period:______
What’s In A Penny?
Introduction: Prior to 1982, all pennies were made of copper. The United States government changed the composition
of the penny at this time because of an increase in the price of copper. By comparing the densities of pennies minted
before 1982 and after 1983, we will demonstrate that the composition of these pennies is different.
Purpose: In this lab, you will calculate the density of sets of pennies minted before 1982 and after 1983 to identify which
metals they contain.
Density formula: Fill in the triangle to the right using the density formula.
Materials: Pre-1982 and post-1983 pennies, a 50 mL graduated cylinder, a beaker of water, a balance and a calculator.
Experimental Procedure:
Part 1: Pick out at least 15 pennies with dates before 1982 and use your mass and volume by displacement
measuring skills and knowledge of density to fill out the table below:
Pre-1982 Pennies
Number of
pennies used
Trial 1
5
Trial 2
10
Trial 3
15
Mass of
pennies used
(g)
Original Volume
(you can use a
convenient
marking)
Volume after
set of pennies
was added
Volume of
Pennies
Used (mL)
Density of
Pennies
AVERAGE DENSITY
Part 2: Pick out at least 15 pennies with dates after 1983 and use your mass and volume by displacement
measuring skills and knowledge of density to fill out the table below:
Post-1983 Pennies
Number of
pennies used
Trial 1
5
Trial 2
10
Trial 3
15
Average Density
Mass of
pennies used
(g)
Original
Volume (you
can use a
convenient
marking)
Volume after
set of
pennies was
added
Volume of
Pennies
Used (mL)
Density of
Pennies
Graphing Data: Graphs are used to visually illustrate data. You will be graphing your 3 data points for the pre-1982 and
post-1983 penny sets, placing volume on the x-axis and mass on the y-axis. Be sure to include everything that is required
in a double line graph.
Conclusion Questions:
1. Should the volume of increasing numbers of pennies used in the trials (circle the correct answer)
a) increase
b) decrease
or c) remain the same
In at least 1 complete sentence, explain your logic:
2) Should the mass of increasing numbers of pennies used in trials (circle the correct answer)
a) increase
b) decrease
or c) remain the same
In at least 1 complete sentence, explain your logic:
3) Should the density of increasing numbers of pennies used in trials (circle the correct answer)
a) increase
b) decrease
or c) remain the same
In at least 1 complete sentence, explain your logic:
4) Examine your data carefully in order to answer the following questions:
a) For pre-1982 pennies, were your calculated densities for trials 1-3 similar?__________
b) For post-1983 set pennies, were your calculated densities similar?____________
c) Which of the sets of pennies had a higher density?_____________________________
6) Assuming that pennies minted before and after 1982/1983 are the same volume, explain which set should be heavier
and why?
Compare your calculated densities to the densities of the following metals:
Symbol
Ni
Al
Fe
Zn
Cu
Hg
Pb
Element/Metal
Nickel
Aluminum
Iron
Zinc
Copper
Mercury
Lead
Density in g/mL
8.9
2.7
7.9
7.1
9.0
13.5
11.5
7) Which metal(s) best match your calculated post-1983 density?