The “Golden Penny” demonstration appeals to many audiences given its visual links to alchemical lore. In the demonstration, a copper coin is plated with zinc, giving it a silver appearance; the zinc plated coin is then heated, generating an alloyed coating of brass (as the zinc and copper mix), making the coin appear gold. Despite the visual appeal of this demo, the methodology utilized for the traditional “Golden Penny” process faces issues relating to safety and obscures the underlying electrochemical nature of the zinc-plating step for most onlookers. Given these limitations, we have worked to develop an electrochemical method to deposit lustrous zinc coatings on copper pennies to improve the demonstration’s safety profile. The updated methodology is versatile and may be used in the classroom as a traditional demonstration or as a laboratory activity to illustrate introductory electrochemical concepts. In addition to the electrochemical methods developed, the straightforward construction and use of an inexpensive trim potential circuit highlight the interconnection of electric and chemical potential for students. Additionally, slight modifications to the base demonstration show students the role of each component of the electrochemical cell (i.e., electrode material, pH, electrolyte, etc.). The effectiveness of this augmented Golden Penny demo in improving both high-school and introductory university students’ understanding of electrochemical terminology and conceptual difficulties was assessed using multiple choice pre/post-test questions and self-reported postactivity evaluations. Students’ scores dramatically increased from the preactivity test (average score: 31.6%) to the postactivity test (average score: 56.1%) representing a 24.6% improvement in score.
Dauzvardis et al. (Thu,) studied this question.