Abstract
This research focuses on the specificities of the symbolic language of chemistry and proposes a didactic reconstruction based on the history of science. The didactic reconstruction should lead to introduce the chemical formulas by creating a dialectic between the empirical register, the register of models and the register of representations. The thesis is structured in three parts:- a preliminary survey to identify students' difficulties related to the learning of symbolic language and the difficulties of teachers at the moment when they introduce this symbolic language. For this investigation, six hundred students responded to a questionnaire and two teachers were followed in their class;- a historical inquiry giving access to the evolution of representations in chemistry and to controversies about the development of chemical formulas in the first half of the nineteenth century;- the development of didactic resources based on historical controversies pointed out by the historical investigation. These are analyzed from spaces of constraints and necessities. Finally, these resources are implemented by two teachers with their students.