Análise histórica do conceito de calor nos trabalhos de Joule e a transposição didática equivalente do mecânico do calor nos livros didáticos de Física

Abstract

The present work aimed to carry out a critical analysis Joule's original texts, written in the middle of the XIX century, trying to understand how the changes in heat concept occurred throughout his work and present a comparative analysis of how the mechanical equivalent of heat theme was presented by the English scientist and how it is approached by high school physics didactic books, investigating the processes suffered by the concept, based on the Didatic Transposition. To support the theoretical analysis, a literature review was made with texts about the Science history and the study of alternative conceptions about heat. Guided by this literature review, the Discursive Textual Analysis was used as the methodology to examine which factors influenced Joule in changing hi conception of the nature of heat. Joule initially accept the caloric theory and, instigated by internal aspects of his research and work by other researchers such as: Rumford, Davy and Herapath, he begins to understand the heat as a state of motion of the particles. We seek to verify how the Joule's work is approached by didactic books, in particular the concept of mechanical equivalent of heat. We found that the concepts suffer depersonalization, desyncretization and decontextualization, resulting in a knowledge devoid of its historical and epistemological context. In addition, didactic books have many distortions and simplications about the images used to illustrate the Joule's famous experiment, the calorimeter shovels. These conclusions serve as warning to those using the didactical books as theoretical teaching, since they reduce the history of science into names, dates and seek to reaffirm inductivists positions. We believe this work will provide subsidies for a possible didactic and pedagogical application, werewas the study of Joule's work can contibute so that there is a heat concept of reframing for students.