Visite guidée d’un laboratoire de physique, une situation didactique

This paper presents a case study of a researcher in physics of granular matters who is explaining to a visitor the experimental research conducted in his lab. We consider the situation as a didactic transaction. We refer to the theoretical framework of the Joint Action Theory in Didactics, and of resources systems of teachers. The central data we analyze are videos shot during the visit. We collect data such as scientific productions of the researcher (posters, papers and thesis). We analyze how the researcher organizes resources, how he introduces knowledge in the ‘milieu’ to communicate his scientific activity and his results, to a public of non-science specialists. We show the relationship between didactic contract and didactic “milieu”, and we show their evolution in a very short episode.