Theories and experiments of an essay on fire

Abstract

The study natural phenomena of interest to society figures among the purposes of science teaching in Basic Education. It is surprising, therefore, that fire receives little attention in science and almost none in education. Even though fire most certainly represents one of the most fascinating manifestations of Nature none of the chemistry collections approved by the National Textbook Program (PNLD 2015) presents any in-depth study on it. But things were different in the past. In order to recover a particular detail of the history of fire as an object of study in chemical philosophy, in this paper we analyze the work An essay on fire, published in 1790 by the celebrated philosopher from Geneva, Marc-Auguste Pictet. Based on the contemporary historiography of science we seek to analyze how fire was explained by some late 18th century theories. The results of this analysis reveal aspects of interest on chemists' style of thinking in the studied context. Pictet's text makes it clear that the word fire was used to designate not only the flame, but an agent responsible for several effects on the structure of natural bodies, such as dilation, changing states of aggregation and chemical decomposition itself. Describing series of experiments, the philosopher analyzes fire from four points of view: liberated fire, specific heat, latent heat, and combined fire. All experiments are preceded by theoretical speculations and results are used as means to accept or to reject such theories. It is also noteworthy that Pictet's approach often oppose corpuscular and vibrational assessments on fire as the causal agency to the effect that we call heat. We conclude that the study of Pictet's work allows us to access some nature of science features, highlighting the importance of communication between researchers, the interdependence between experiments and theories, and the coexistence of different models to represent a phenomenon under study.