Name: _______________________________________ Per: ____
A Penny for your Thoughts
This lesson utilizes the following Science and Engineering
Practices (http://standards.nsta.org/Standards/DisplayStandard.aspx?view=topic&id=19)
Planning and Carrying Out Investigations
Planning and carrying out investigations to answer questions or test solutions to problems in 3–5
builds on K–2 experiences and progresses to include investigations that control variables and
provide evidence to support explanations or design solutions.
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Conduct an investigation collaboratively to produce data to serve as the
basis for evidence, using fair tests in which variables are controlled and
the number of trials considered.(5-PS1-4)
Make observations and measurements to produce data to serve as the
basis for evidence for an explanation of a phenomenon.(5-PS1-3)
Using Mathematics and Computational Thinking
Mathematical and computational thinking at the 3–5 level builds on K–2 experiences and
progresses to extending quantitative measurements to a variety of physical properties and using
computation and mathematics to analyze data and compare alternative design solutions.

Measure and graph quantities such as weight to address scientific and
engineering questions and problems.(5-PS1-2)
This lesson encompasses the following Disciplinary Core Ideas
Measurements of a variety of properties can be used to identify materials. (Boundary: At this
grade level, mass and weight are not distinguished, and no attempt is made to define the unseen
particles or explain the atomic-scale mechanism of evaporation and condensation.)(5-PS1-3)
This lesson deals with the following Crosscutting Concepts
Standard units are used to measure and describe physical quantities such as weight, time,
temperature, and volume.(5-PS1-2), (5-PS1-3)
Name: _______________________________________ Per: ____
Materials
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A collection of pennies from the 60’s/70’s through the present. It’s helpful to have students
bring in and sort the pennies into coin envelopes or plastic containers labeled with the penny
year.
A set of either triple beam or electronic balances measuring to 1/100 of a gram
A spreadsheet program, e.g. Microsoft Excel, to communicate their findings in the form of a
graph or table. Graphs can also be made by hand if this is more convenient.
o Note: MS Excel can only deal with numbers. Penny sounds will need to be represented
by numbers, e.g. 1=high ringing sound, 2=low dull sound
Exploration
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Ask students what would happen if pennies were made of gold and the value of the metal in the
coin was more than the value of the coin.
o Try to steer students to the idea of pulling up to your local bank, asking for all of your
money in pennies and then selling them for scrap and making millions of dollars
Drop a copper penny (pre-1982) and a zinc penny (post-1982) on a table/desk and ask student
to listen to the sound
o The pre-1982 (copper) penny with have a high ringing sound and the post-1982 (zinc)
one will have a dull, lifeless sound
Read through “Background” and “Purpose” section of the lab with students
Put students into groups of 2-3 students
Allow groups to test either sound or mass. If they choose to test sound, provide them with a
known copper penny(old) and a known zinc penny(new) to compare penny sounds to.
Note: Penny material change happened in 1982. Some 1982 pennies will be zinc and some
copper
Instead of assessing students using a lab report, you could turn this into a class discussion or
create a more structured laboratory experience by giving students pre-made tables to fill in
A fun thing to do is to get a hold of some 1943 zinc-coated steel pennies (available on Ebay) and
show these to students
Name: _______________________________________ Per: ____
Example data for both sound and mass
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
3.11
3.1
3.05
3.35
3.14
3.23
3.08
2.04
3.09
3.09
2.18
2.53
2.52
2.5
2.63
2.63
2.42
2.72
2.82
2.5
2.5
Sound
(2=high,
1=low)
2
2
2
2
2
2
2
2
2
2
2
1
1
1
1
1
1
1
1
1
1
Penny Sound and Year
3
Sound 2=High, 1=Low
Mass
(g)
2
1
0
Year
Penny Year and Mass (g)
4
Mass in Grams
Penny
Year
3
2
1
0
1972 1974 1976 1978 1980 1982 1984 1986 1988 1990 1992
Year
Name: _______________________________________ Per: ____
Penny Lab Report Activity
Background:
The materials that make the U.S. Penny have changed many times in the past
150 years. For many years, copper was the main ingredient in the penny.
Pennies were 95% Copper and 5% Zinc. During World War II, copper was
needed to make ammunition so pennies were made of zinc-coated steel
in 1943. After World War II, the penny’s composition went back to 95%
copper and 5% zinc. This stayed the same for some time, but as copper
got more expensive, the material value (cost of the materials) of the
penny approached 1 cent. Because of the increasing price of copper, the
U.S. mint (where money is made) decided that they could no longer use that
much copper and needed to use different metals for the penny. As a result, the
mint switched the values for zinc and copper, and today the penny is 95% zinc, and
only 5% copper (coating).
Purpose:
Design, conduct, and report on a Lab experiment using mass or sound that will determine what year the
composition of the U.S. Penny changed from 95% copper to 95% Zinc.
Key things to think about when planning your lab experiment:
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Copper pennies weigh more than zinc pennies.
When dropped on a hard surface, zinc pennies make a higher pitched sound than copper
pennies.
What is a controlled experiment?
What is going to be your manipulated variable?
What is going to be your responding variable?
How are you going to measure your data?
What kind of graph could you use to help communicate your data?
How much data do you need to collect to make sure your results are reliable?
The experiment can be designed and completed in groups of 2 or 3. Each person needs to complete a
lab report. You will have three days to design, complete, and collect data on your experiment. You’ll
have two days to complete your lab report.
Name: _______________________________________ Per: ____
Include the following parts in your lab report:
1. Purpose:
The purpose of this lab is to investigate the relationship between_________ and penny year.
2. Background:
Background information you provide to help the reader better understand the lab report (this
has been given to you already)
3. Question/Problem statement:
What question are you trying to solve or better understand?
4. Hypothesis/Prediction:
What do you expect the results to be?
Why do you expect to get these results?
5. Procedure:
Steps should be listed and numbered
Steps should be clearly written giving necessary details.
6. Data:
Data and correct graph
7. Analysis:
Describe the data. Are there any patterns? Are there any irregularities in the data (outliers)?
Provide possible explanations for these.
8. Conclusion:
Restate the purpose.
What did the data tell you? Can you draw a conclusion about the relationship of the variables?
What additional questions do your findings raise? (follow up questions you’re curious about)
9. References:
List of references