Cette recherche, s’appuyant sur les spécificités du langage symbolique de la chimie, propose une reconstruction didactique fondée sur l’histoire des sciences. Celle-ci doit permettre d’introduire les formules chimiques en créant une dialectique entre le registre des représentations, le registre empirique et le registre des modèles. La thèse se structure en trois parties :- une enquête préalable permettant d’identifier les difficultés liées à l’apprentissage du langage symbolique, à partir d’un questionnaire auprès de 600 élèves, et à l’enseignement du langage symbolique de la chimie à partir de deux études de cas d’enseignants dans leur classe ;- une enquête de nature historique donnant accès à l’évolution des représentations utilisées en chimie et aux différentes controverses qui ont traversé la première moitié du XIXe siècle au moment de l’élaboration des formules chimiques ;- l’élaboration de ressources, à partir des controverses repérées dans l’enquête historique et analysées à partir d’espaces de contraintes et nécessités, puis la présentation de leur mise en œuvre réalisée par deux enseignants avec leurs élèves. / 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.

My PhD study 'Educational application of models of complex biochemical processes' discusses the possibility of integrating simple bioorganic teaching experiments, modelling complex biochemical processes in living systems into a curriculum of secondary schools, and universities, and even elementary schools in some cases. The aim of these experiments is simplified, but illustrative and appropriate for approaching complex problems of biochemical processes in a transparent experiment, running in spite of conditions comparable to real natural clauses in a living system. The theoretical part is divided into three thematic circuits: biochemistry and bioorganic chemistry, bioorganic models and their characteristics and selected specific forms of applying bioorganic models into teaching chemistry. The next part dealing with bioorganic models and their characteristics is further divided on the base of some specific models. These are consisted of models of enzymes and their catalytic activity, models of biochemical reactions and antidotal and toxic substances affecting life-forms and their carcinogenic efficiency. The practical part contains methodic treatment of six selected models that demonstrate specific biochemical processes or structure of complex organic compounds. These models include modeling biuret...