Explorando episódios históricos no ensino de física: o calor como radiação em fins do século XVIII

Abstract

The study we conducted involving the relationship between History and Philosophy of Science and Science Teaching assumes that these two fields can be related at four levels: a conceptual, an epistemological, a socio-cultural and a motivation level (SEROGLOU and KOUMARAS, 2001; SEKER, 2012). Of these levels, this study aimed to explore a historical episode in which the conceptual and epistemological aspects were highlighted; more specifically, the first impressions on the relationship between the color of the light spectrum and the emission of radiant heat, and the experiments that sought to verify this relationship. To this end, we study in detail the experiments carried out by William Herschel (1738-1822) on radiant heat, more precisely the experiments in which he investigated the power of heat and light of different colors and verified the existence of radiation beyond the visible spectrum and its construction of spectra of light and heat. Based on the hypotheses developed by Herschel and the results he obtained, we propose the discussion of conceptual issues, such as the constitution of the light spectrum, the phenomena of refraction and reflection of infrared light and the measurements of light intensity. Epistemological and methodological aspects are also taken into account, such as the question of cause and effect, as well as the accuracy of measurements and the disagreements emerged by the experiment at the time. It is noteworthy that even containing a number of limitations from the experimental and methodological point of view, the experiment by Herschel is regarded as crucial in the detection of infrared radiation. As for the educational material, we adopted the historical case study (STINNER, et. al., 2003), by developing a paradidactic material in which we contextualize the activities of Herschel; present in detail one of his experiments and a possibility of didactic reproduction; and highlight the consequences of these results in current technologies involving infrared radiation.