Induced misinterpretations: The case of the sulfur phase diagram Interpretaciones erróneas inducidas: el caso del diagrama de fases del azufre

Abstract

Pure substance phase diagrams, as pressure versus temperature graphs, are usually introduced in first university courses in chemistry. In general, off-scale schematic diagrams are used to cover a full range of pressures and temperatures. In them, to highlight certain behaviors of the substances, some details are accentuated or exaggerated, and this implies a greater risk of inducing comparative misconceptions than using scale diagrams. Taking in account that graphic representations are important tools in the teaching of concepts and in the recognition of physical and chemical phenomenologies, to avoid conceptual errors, schematic diagrams and their inherent distortions should be carefully discussed with students. In the present work, the sulfur phase diagram is taken as an example, because, both in textbooks and in scientific articles, it is often shown with some qualitative errors.