Cart
Article
Do New Pennies Lose Their Shells? Hypothesis Testing in the Sophomore Analytical Chemistry Laboratory
Hi-Res PDFPurchase the full-text
- PDF/HTML,
figures/images,
references and tables,
(where available)
Abstract
Post-1982 pennies have a varying copper content that can be investigated in the introductory analytical chemistry lab. Groups of four students analyzed ten pennies sampled from the entire minting period to test the hypothesis that the copper shell wears out with time. The results of the flame atomic absorption spectrometry measurements disproved the hypothesis. Four groups observed an increase of 2 mg of copper per year of circulation, the opposite of the behavior expected if the hypothesis were true. Two groups reported a strong positive correlation between copper content and original penny mass. Only one group observed random variations in copper content. Copper-clad copper pennies have a dynamically changing copper content that could be the result of minting variability or changes accompanying the storage of pennies. Student reactions to these results are noted. Future experiments are suggested.
Keywords (Audience):
Second-Year UndergraduateKeywords (Domain):
Laboratory InstructionKeywords (Pedagogy):
Hands-On Learning / ManipulativesKeywords (Subject):
Quantitative AnalysisCiting Articles
Citation data is made available by participants in CrossRef's Cited-by Linking service. For a more comprehensive list of citations to this article, users are encouraged to perform a search in SciFinder.
This article has been cited by 1 ACS Journal articles (1 most recent appear below).
The Penny Experiment Revisited: An Illustration of Significant Figures, Accuracy, Precision, and Data Analysis
Joseph BularzikJournal of Chemical Education2007 84 (9), 1456The Penny Experiment Revisited: An Illustration of Significant Figures, Accuracy, Precision, and Data Analysis
Joseph BularzikJournal of Chemical Education2007 84 (9), 1456Measuring the mass of many pennies has been used as an easy way to generate data for exercises with statistical analysis. In this general chemistry laboratory the densities of pennies are measured by weighting the pennies and using two different methods ...
Tools
-
Add to Favorites
-
Download Citation
-
Email a Colleague -
Permalink
Order Reprints
Rights & Permissions
Citation Alerts
History
- Received: August 03, 2009
ACS
Network
Facebook
Tweet This
CiteULike
Newsvine
Digg This
Delicious
