A Table-Top Cloud Chamber to Observe Radioactivity in the Uranium Decay Chain

As part of their third-year general chemistry program, students at the University of the Cote d'Azur are taught the basics of radioactivity. The view that third-year university students have of the periodic Table of the Elements is often reduced because it ignores the vast majority of isotopes. As part of this program, a practicum devoted to the observation of alpha and beta particles has been put in place and a table-top version of a cloud chamber of the Langsdorf type was designed, but in its simpler, static version. With a simple experiment and a source of natural uranium, concepts that normally belong to the distinct disciplines of thermodynamics, classical point physics, nuclear instability, and even chemistry are being addressed in a complementary manner. This article gives a full description of the various concepts that may be taught during the practicum, together with the basic equations. Numerical applications performed with observed data are proposed and discussed together with tabulated data. Through this practicum, students can actually observe radioactivity directly and come to understand that nuclides may be stable or unstable.