In this article we describe an educational activity on radioactive equilibrium we performed with
secondary school students (17–18 years old) in the context of a vocational guidance stage for
talented students at the Department of Physics of the University of Pavia. Radioactive equilibrium
is investigated experimentally by having students measure the activity of 214 Bi from two different
samples, obtained using different preparation procedures from an uraniferous rock. Students are
guided in understanding the mathematical structure of radioactive equilibrium through a modelling
activity in two parts. Before the lab measurements, a dice game, which extends the traditional
‘radioactive dice’ activity to the case of a chain of two decaying nuclides, is performed by
students divided into small groups. At the end of the laboratory work, students design and run a
simple spreadsheet simulation modelling the same basic radioactive chain with user defined decay
constants. By set…