Faire concevoir le protocole de mesure de l'angle facial à des élèves de terminale S : difficultés et recommandations

Session 6 : EDUCATION ET CULTURE : Les publics, les primates et l'évolution; International audience; Experimental design procedure task is largely studied by several researches in education in the aim to understand its characteristics and to study what added values for students when they have to design it. The results show that students designing their own experiments advanced their scientific abilities such as ―to identify and evaluate sources of uncertainty, their ability to minimize uncertainty, their ability to identify the implicit assumptions, and their ability to evaluate their experimental result by means of an independent method‖ (Etkina el al, 2010, p. 89). Students involved in designing experimental procedures spend much time to discuss about their experiments, to critic them and to revise them. Designing activity involve them in metacognitive reflexion such as planification, evaluation of methods and results. This study investigates students' design of measurement procedures as a way of attaining a more direct understanding of the underlying scientific concepts involved in experimentation itself. The classical experimental procedure studied in this article of measuring facial angle might be employed by students of human evolution at higher secondary level to find out the species identity of a human cranium. This might be done in a recipe type manner. As opposed to simply carrying out an experimental procedure as is often the case in lab work, we here present students with a cognitive task which involves the construction of their own procedure and we then analyse carefully the merits of this approach for understanding not only the processes of experimental design but also ways of improving such science practice and pedagogy. Our qualitative analysis of the devised student methods revealed four obstacles: Choice of an appropriate referential system (support table and sheet), graphical notation of angles, reproducibility of points on other crania, and the communication demands of the situation. We suggest that asking students to design an experimental procedure is a valued and valid problem solving activity, in which students conceptions are ate root of both procedural strategy and hypothesis making.