For several years now, the LDP has been focusing specifically on the difficulties pupils and students have in learning physics. The didactics of physics is specifically concerned with the elements intrinsic to the disciplinary content taught that constitute genuineepistemological obstacles to the construction of knowledge. Indeed, physics, because it presents a high degree of conceptualization, is particularly difficult to understand, to learn and therefore to teach. These obstacles to learning are essentially revealed in learners by the mobilization of their so-called primary or spontaneous conceptions. Thisprimitive knowledge, generally false, is generated during reasoning that is described as naive, because easy to mobilize, but scientifically incorrect. Being able to detect, in learners, these false reasonings, generators of primary conceptions, means setting up teaching devices, a more effective didactic engineering in order to improve learning. For example, the use of a video capsule of a physics experiment is not as efficient as one might initially think.

• Gabriel DIAS DE CARVALHO JUNIOR