A utilização de modelos didáticos, na forma de analogias, no ensino de isomeria 3D : uma investigação dos saberes docentes junto a professores de química

Abstract

This research was carried out in order to examine how a group of three chemistry teachers of a federal educational institution experienced in the classroom at work a rather abstract content called the stereoisomerism or isomerism (3D), a term used in the research, aiming to contribute to the formation of this teachers class. This content involves geometrical isomerism and optical isomerism. This analysis involved the determination of educational models through the use of analogies used by teachers and the determination of knowledge mobilized by them during their classes or at least the knowledge that should be mobilized. Theteachers have given two lessons each on the isomerism (3D). These lessons were observed and shooted by a third agent and then the speeches of teachers were transcribed, and some observations were made about their ways of doing things in the classroom and the way theyexplained the contents. Preliminary analysis of the transcribed speech was carried out by an association between the steps taken by teachers in their classes using analogies and a rational use of methodology of analogies, the TWA (Teaching With Analogies). After an initial analysis of the teachers’ speeches a supplementary questionnaire was drawn up so that the teachers could answer itbased on these lines in the classroom and aiming to bring relations between the knowledge mobilized by teachers and analog models used in classes on the isomerism (3D). The results showed, in general, that teachers have used three types of analog models for their explanation of the isomerism (3D), concrete, operational and the model with multiple analogies. The teachers have used such models without rigor spontaneously and they have used analogies without worrying about the students' prior knowledge, for example, if they know the difference between the analogy used and the subject of the lesson. It was determined also that knowledge of the content, according to Shulman, presented by teachers is very significant; however, the curriculum knowledge and teaching are at lower levels than one would expect for such teachers who are experienced. Finally, we found some shortcomings regarding the training of these teachers, through the fault pointing the pedagogical reasoning that should have developed over the years, according to Shulman, as some steps you should follow and which relate to assessment during the process of reflection and teaching to resume the process, present in the pedagogical reasoning.