Mass from Classical Physics to Special Relativity: Learning Results

Mass is a fundamental multifaceted physical quantity, involved in courses from primary to secondary school. Its equivalence to rest energy is very important as well. Educational literature indicates remarkable problems in high school textbooks, misconceptions concerning E0=mc2, and a qualitative view of mass, with a teleological connotation. We therefore carried out a research into the learning paths of 42 skilled students attending a modern physics summer school, by means of an interactive tutorial. “Relativistic mass” conception was investigated too, as an important spin-off. Our main findings concerning the classical part of our working sheets were that 76% of students associated mass with mechanical phenomena and that the pre-theoretical conception quantitas materiae was rooted in some minds (between 12% and 15% of the sample); only 26% recognized mass explicitly as important in gravitational interaction between bodies, even if gravitational mass was considered by 50% as a parameter describing a generic interaction between bodies. Inertial mass was instead understood as given by Newton’s second law by most students. As for relativistic part, mental representations of mass seemed to be related to students’ learning environment. The young talents were very good at formalizing, mass-rest energy relationship being a striking exception: The “relational level of physical representation” prevails over other “levels”. Eventually, no statistical significant correlation was found between the presence of the concept of mass as rest energy and the understanding level of “relativistic mass” (even if a sort of negative correlation between the former and the latter can be seen in their plot).