On Joule’s paddle wheel experiment in textbooks II

Abstract Joule’s paddle wheel experiment has become famous in the history of physics. Illustrations of the experiment have appeared in textbooks since the 19th century. However, the textbook diagrams of Joule’s experiment differ from each other, and most differ from the original diagram. The differences appear to be significant. The question of whether the results of the experiments are the same in each of the experimental configurations is addressed in this paper. In order to answer this question, a replica of the original calorimeter was built. The results obtained were compared with those obtained using machines that corresponded to the schematics of the experiment in physics textbooks. This comparison gives us a new insight into the potential energy transformed into heat.