A comparison of a pennies mass to the year it was minted

A comparison of a pennies mass to the year it was minted
By Trevor Gustafson



Introduction:
This experiment was done to discover the relationship between a pennies weight and the year it was minted. My assumption going into this experiment was that the pennies weight would slowly decrease over time due to wear.


Materials used:
· 1 penny from the 1960’s
· 2 pennies form different years in the 1970”s
· 3 pennies from different years in the 1980’s
· 3 pennies from different years in the 1990’s
· 1 penny from the 2000’s
· 1 scale
· 1 pencil
· 1 notebook


Procedure:

· Create a hypothesis
· Graph predicted outcome
· Weigh individual pennies and mark findings on a chart
· Mark findings along with classmates findings on a graph


Results:
· See attached Figure 1. “Predicted results of the comparison of a pennies mass to the year it was minted.”
· See attached Table 1. “Personal data concerning the comparison of a pennies mass to the year it was minted.”
· See attached Figure 2. “Group data concerning the relationship of a pennies mass to the year it was minted
· See attached Table 2. “Group data concerning the comparison of a pennies mass to the year it was minted.”






Analysis

1 Plot your data on graph paper as a scatter plot. Show the mass of each penny in grams on the y-axis and the year the penny was minted on the x-axis. Plot both the class data and your individual data on the same graph. Highlight the points that correspond to your individual data
· See Figure 2: “Group data concerning the relationship of a pennies mass to the year it was minted”

2 Are the experimental results consistent with you hypothesis? If not, propose a new hypothesis
· No.
· The older pennies were actually heavier than the newer pennies
· The change was not gradual, but happened suddenly around 1982
· My new hypothesis is
“When measuring the pennies to one decimal point, it appears that circulation has very little effect on a pennies weight. Something outside of circulation, such change in manufacturing the penny, must have played a part in the pennies weight.”

3 What effect might aging have on the mass of a nickel, a dime, or a quarter

· Those coins are made of different materials so we can’t know what affect aging would have on them from this experiment.

4 Would using a balance that was many times more sensitive have made a difference in your conclusion about the effect of aging on a penny?
· Possible. The greater sensitiveness might have yielded different results.

5 What improvements might you have expected in you graph if only one student had done all the weighing on a single balance.
· Taking out variables such as multiple students and balances would probably had yielded a more consistent graph.

6 Compare your individual graph to the graph of class data. Why might you expect better results with the entire class data set than with your individual data set?
· Because most of the dots up until 1982 fell on 3.1 and most of the dots after 1982 fell on 2.5. I believe that the few odd ball points on the graph may have been miss-calculations