Résumé
Many decisive issues for our society’s future are linked with sciences and technologies. With an education to citizenship in mind, train students to reflectively take part in debates on Socio- Scientific Issues (SSI) has become a major concern. In particular, pupils need to develop their critical thinking and argumentation skills, and to grasp the complexity and openness of SSIs. In this respect, computer-mediated debates provide new learning opportunities to carry out debates in classrooms. But what is precisely their contribution? In particular, what are the contributions to help students develop argumentative skills and critical thinking on SSIs and grasp the complexity of these issues? In this PhD work, i present and analyze the implementation of a teaching sequence in nine high school classes. This sequence is centered on a computer-mediated debate, using an online platform which starts the debate from a text and not a question. To assess the quality of argumentation and the structure of the debates, I used an analysis grid based taking into account its process and product aspect, and its dialogical and monological dimensions. The analysis could not highlight significative evolutions of pupils’ argumentative skills, notably because of the high context-dependency of the argumentation. This leads to develop our teaching sequence and assessing method. Nevertheless, the analysis show that a text-based computer-mediated debate helps students grasp and give rise to questions which are meaningful for them. It also allows them to tackle the various dimensions of the SSI while collectively and simultaneously investigating the issue.