The use of stop motion in researching of mental models of high school students on concepts related to electrolysis

Abstract

In this research, mental models expressed about electrochemical systems were analyzed, specifically related to the aqueous electrolysis of sodium hydroxide. The methodology consisted of applying a short course for high school students from a state school in the west of São Paulo, with the conducting of experiments and development of animations using the Stop Motion technique by the students, through which their mental models were analyzed regarding the processes of transfer of electrons that occur in the electrodes, in addition to the release of different gases as a consequence of ion discharge reactions, and to the kinematics of subatomic species. The methodological analysis was based on Johnson-Laird's theory of mental models, in which the collected material, whether imaged or written, was analyzed according to the presence of elements (tokens) characteristic of the expressed mental models. The results of a previous questionnaire showed that students have superficial notions about electrochemistry in general, as they had difficulties in how electrolysis occurs, in locating the cathode and anode and in understanding how the flow of electrons in systems through oxidation-reduction reactions. The explanation of the concepts involved, the carrying out of experiments and the subsequent production of stop motion animations by the students allowed them to locate their main difficulties in understanding electrolysis. Through the animations, it was possible to locate incoherent aspects and flaws in the mental models, related to the notions of loss and gain of electrons, reaction stoichiometry and movement of chemical species. From a knowledge of the students' expressed models, it was possible to work on specific points in the explanation of electrolysis and contribute to construction of more adequate models by students about the content at its submicroscopic level. The use of the Stop Motion application in the development of animations proved to be interesting in the teaching of Chemistry and Science, as it stimulated imagination, creativity, critical reflection and logical thinking regarding the dynamics of chemical species.