As estratégias de ensino utilizadas por dois professores de química para auxiliar no desenvolvimento de habilidades de visualização e representação molecular

Abstract

In this work we analyze the strategies used by chemistry teachers to assist in the development of visualization skills and molecular representation by students. In addition, we investigated, through the analysis of interviews with teachers, aspects of the professional trajectory that influenced their practices, outlining their current performance. We rely on the Mediated Action Theory proposed by Wertsch (1998) and their properties: (i) irreducible tension between the agent and the mediation instrument, (ii) the mediation instruments are material, and (iii) the mediation instruments restrict and allow action. We selected a professor of General Chemistry at UFMG and a professor of chemistry at a high school in the private system of Santa Luzia. In the development of this research, we describe the strategies used by teachers, when acting with visualization tools, to evidence how they help students develop visualization and molecular representation skills in their Chemistry classes. To do this, we constructed episodic maps, coding maps of the use of visualization tools throughout the classes analyzed, graphs of percentage of use of visualization tools, among others. With this, it was possible to describe the analyzed classes, to categorize the visualization tools used and to identify the strategies that each of the teachers used in their classes to favor the students the development of the mentioned skills. The research results showed that teachers plan how and when the visualization tools will be used in their classrooms. Therefore, the order in which they appear is an essential factor in achieving the objectives proposed by teachers, even if they appear as idiosyncratic. We found that the visualization tools have their own potential, restricting or allowing the action of teachers. Due to this property of the Mediated Action, it was possible to perceive the complementarity in the use of the different visualization tools in the classes of the analyzed teachers. We realized that several strategies could allow the development of molecular visualization skills and / or molecular representation. Some strategies were coincidental for teachers. This fact may indicate that the potentialities of these visualization tools can lead teachers to create similar strategies to reduce these limitations. We perceive that the actions of teachers in the classroom, show the irreducible tension between the teacher and the visualization tools. We believe that the results of this work bring contributions to the area of chemistry teaching by presenting significant results on the strategies used by chemistry teachers, at two levels of teaching, to teach contents related to the molecule concept, with a view to engaging students and the development of skills