This article aims to shed light on teaching practices in didactic institutions that are located at the "frontiers" of the School. We are interested in the partnership between classes and scientists within the framework of a project of citizen sciences deployed in Europe (the Oak bodyguards project). Our work is based on the articulation of three conceptual sets: teaching practices, continuity of experience and knowledge in science. The first results highlight in particular that all the teachers say they have enrolled their students in this project so that they can practice “authentic” science.