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).
