MASS CONSERVATION IN CHEMICAL REACTIONS: THE DEVELOPMENT OF AN INNOVATIVE TEACHING STRATEGY BASED ON THE HISTORY AND PHILOSOPHY OF SCIENCE

Abstract

A detailed analysis of recent Portuguese Curricular Reform materials (low secondary school, 13-15 years old students) shows that the topic of "mass conservation in chemical reactions" is a central one. However, the proposed teaching approach is a traditional one, emphasizing the learning of isolated concepts and science processes. New and different teaching approaches are necessary and these must consider the history and the philosophy of science, so that aspects related to the context of discovery are also considered. This is an important point in the light of new Science Education aims, which take into account the development of adequate images of science and scientific knowledge. The main aim of this study is to present and discuss a new teaching approach based on research carried out in the last four years. The main lines of the approach presented is epistemologically based on the New Philosophy of Science. It departs from the combustion reactions and their contemporary economical, environmental, social and political contexts (exploring STS perspectives in the teaching of science). Its exploration is centred upon the context of oxygen theory discovery and the main teaching aims are discussed. Strategies, activities and materials used are presented and their educational purposes are accounted for with reference to the theoretical framework developed. Internal evaluation based on feedback of the two teachers who developed the strategy and of the students involved converge towards the acknowledgment of the interest of the new proposal. [Chem. Educ. Res. Pract. Eur.: 2000, 1, 201-215]