The beta decay and the conservation of energy: A historical case-study to overcome learning difficulties in the upper secondary school

This theoretical paper provides a case-study in the history of nuclear physics that could likely help overcoming a learning difficulty that upper secondary school students have in dealing with conservation of energy topics. As reported in the physics education literature, among the learning difficulties encountered by the students figures indeed limiting the validity of the principle of conservation of energy to mechanical and thermodynamic processes. The historical case-study here proposed concerns Bohr-Pauli controversy in late 1920s to early 1930s about the continuous beta decay spectra. As it is well known, in order to explain this feature of the beta decay, Bohr suggested a violation of the principle of conservation in radioactive processes. On the contrary, Pauli defended the view that the unobserved portions of energy was carried off by one, or more, very light neutral particles, eventually named neutrinos.