Didactic and epistemological study of the difficulties of studying the concept of redox in secondary education (Morocco)

Abstract

The concept of redox presents difficulties in its teaching and learning. The purpose of this research is to make a double epistemological and didactic analysis of the achievements of two hundred and fifty Moroccan students of scientific sections on this concept and to locate the difficulties they encounter in this regard. The didactic analysis is based on the content set by the curriculum; and the epistemological analysis is carried out through a questionnaire on the knowledge, understanding and application of this concept during the school year 2019/2020.

The results showed that redox reactions are only taught in the 1st year of the baccalaureate, whereas in the 2nd year, students use the basic concepts of redox already seen. Most of the students questioned are unfamiliar with the concept of redox, the conceptual network associated with it and its application. Indeed, learning about redox centered on the electron transfer model does not allow the learners to make the link between electron transfer and the transfer of hydrogen and oxygen. Also, the percentages obtained show that the students are far from mastering all the basic notions related to this topic.

The main difficulty was related to conceptual difficulties. Students had great difficulty in differentiating between the terms oxidant and reductant, and reduction and oxidation, as well as in identifying the equations of redox reactions. This leads us to think about the use of mnemonic models suitable for these purposes, and especially to propose to the teachers a training based on new approaches (TPaCK) to improve and facilitate the learning of this kind of concept through the creation of adequate digital teaching resources.