Transformation of didactic intentions by teachers: the case of geometrical optics at grade 8 in France
Colette Hirn
This investigation is grounded on the following idea : as regards the implementation of research based innovations, teachers are not passive transmitters, and there are some general trends in the way they transform the proposed teaching strategies. This thesis deals with the particular case of elementary optics at grade 8 in France, a syllabus launched at national level in 1993. Four sets of data -interviews before teaching, logbooks, assessment tasks and video recorded class observations - lead to converging conclusions. In particular, the great importance of practical devices is shown, as vehicles for pedagogical strategies: if these devices are classical, they entail ways of doing that are classically linked to these devices, and therefore they contribute to blocking innovative strategies in teachers. If they are innovative, they seem to foster the actual introduction of the suggested new ways of teaching. More generally, the "seeing is enough to understand " perpective seems to have inspired a large part of teachers' actions - planning of sessions, assessment tasks, actions in class - and comments in interviews. "Reasonned experimentation", although presented by the conceptors as a major focus of the syllabus, leaves a non negligible fraction of teachers on their initial position, that is an emphasis on showing and classifying objects more than analysing the underlying concepts and laws. This investigation shows, with some examples analysed in detail, that beyond a global "view on science" the very understanding of some concepts is affected by the coexistence of the old and the new in teachers' practice. Outcomes for teacher training are discussed. These conclusions suggest the interest of extending such research to others topics and provide some hints on how to design innovations with maximised chances of appropriate implementation by teachers.