The purpose of this manuscript is to characterize the ways highschool students can grasp nanotechnologies controversies and to identify how they critically consider different discourses held by different actors about these technoscientific developments. As a first step, we completed an analysis of the controversies raised in France by nanotechnologies. It showed that in addition to questions about the products of nanotechnologies and their effects, the ways nanotechnologies' programs are developped and currently exist in our societies constitute a bone of contention. We used this epistemological and sociological analysis of the controversies as a touchstone to progressively design a set of school activities. To elaborate them, we also resorted to a design-based research approach and implemented them with four groups of about 30 15-17 years old students. The final pedagogical sequence consisted of a role play, a webquest and a last activity were students completed a text summarizing their collective stance on nanotechnologies developments. The analysis of students' oral and written productions that we have carried out, is twofold. In order to characterize their collective understanding of the controversies raised by nanotechnology, we analyzed the contents of students' interventions by using Albe's (2007) model on schooling socioscientific controversies. Moreover, attention was paid on how students' critically consider discourses on nanotechnology, in particular by identifying fallacies in their argumentation. This was performed following a pragma-dialectical approach of argumentation (van Eemeren and Grootendorst, 1996, 2004). These analyses showed students grasped many aspects of the controversy. They proved able to understand some documents directly emanating from the social space. They also critically discussed some discourses held on nanotechnologies, in particular the ones they regarded as acceptability discourses. However, when expressing their opinions, students tended to reproduce a common and vague stance asserting that nanotechnologies developments is to breed benefits but also entails some “ risks that have to be taken into account ” and that the public has to be informed about them.
