I am fascinated by the chemistry of pennies. Dissolving a penny in nitric acid is one of the most visually stimulating chemistry reactions I have ever seen. The combination of a bubbling green solution and noxious brown gas that changes the color of an acid base indicator enlivens any discussion on redox chemistry.
Likewise, the golden penny experiment is pretty cool, too. In this experiment, a penny is plated a penny with a silvery zinc coat that subsequently turns a golden color when heated. There are a large number of other chemistry experiments that use pennies. Erica Posthuma-Adams recently described a boat building experiment in which students design and build boats; pennies are used as weights to test each boat’s seaworthiness. Finding the density of pennies is another classic chemistry experiment.
My favorite penny experiment is melting pennies. It is simple to conduct and it can be used to discuss a variety of chemistry topics. Check out the video below.
I would love to learn more about the chemistry of pennies and other coins. If you have any experiments to share, I would enjoy hearing from you.
You can find out more about the composition of pennies as well as more experiments to do with pennies in the Journal of Chemical Education. A small sample of articles on pennies is listed below.
N. C. Thomas and S. Faulk, A Simple Penny Analysis, Journal of Chemical Education, 2008 85 (6), 817. (accessed 2/13/19)
R. F. Mauldin, Introducing Scientific Reasoning with the Penny Lab, Journal of Chemical Education 1997 74 (8), 952. (accessed 2/13/19)
I. A. Leenson, More Experiments in the Penny Lab, Journal of Chemical Education, 1998 75 (11), 1362. (accessed 2/13/19)
P. D. McCormick, Chem 13 News Digest: Brass, Journal of Chemical Education, 1975 52 (2), 102. (accessed 2/13/19)
J. M. Miller, Analysis of 1982 Pennies, Journal of Chemical Education, 1983 60 (2), 142. (accessed 2/13/19)
Please refer to the ACS Guidelines for Chemical Laboratory Safety in Secondary Schools (2016). Some additional information on these guidelines can be found in a Pick at ChemEd X.
RAMP: Recognize hazards; Assess the risks of hazards; Minimize the risks of hazards; Prepare for emergencies