The study of students’ mental representations of Natural Sciences concepts and phenomena constitutes a central part of Science Education research, as they play a decisive role in teaching. In the study presented here, we investigate 157 ninth grade students’ mental representations of the magnetic field, after they were taught about it in school. The empirical data was gathered through an interview using 4 tasks which involved the evaluation of actual or hypothetical situations. The research data included mental representations that cause difficulty in the comprehension of the properties of the magnetic field.
The results of all four tasks show that the students face considerable difficulty in evaluating actual or hypothetical experimental situations involving the application of the properties of the magnetic field. It is indicative that, with the exception of the task concerning the exertion of magnetic forces in air to which approximately 4 out of 10 students responded adequately, in the remainder of the tasks only about 1 out of 10 students are able to fully process the situations presented, to express reasoning and formulate hypotheses based on declarative school knowledge. Of course, this is not solely due to the inadequate comprehension of magnetic properties (as in Task 4, concerning the permanent magnetisation of certain substances), as well as the inability to correlate characteristics caused by the magnetic field and the rest of the characteristics of the experimental situation. For example, as we saw in Task 3, the exertion of interactive forces on the magnetic field is closely linked to the question of interactive forces within a field, which is a problem we generally come across (Solomonidou & Kolokotronis, 2001). We could, therefore, address the question of organising the appropriate teaching activities in order to make the properties of the magnetic field better understood, as well as the question of reorganising sections of the curriculum in order for the study of magnetic properties to become systematically linked to questions of the general properties and the nature of fields. Especially, the discussion about tasks 2 and 3 indicates that any teaching intervention about magnetic field is fruitful to be designed in connection students’ mental representations about Newtonian model.
Moreover, it appears that a discussion concerning a satisfactory comprehension of the magnetic field has to encompass not only the specific properties of the magnetic field, but also the special applications of these properties in various experimental situations. This will make it possible for students to elaborate magnetic properties in a functional way and to alternate back and forth between the model and reality, finally arriving at the construction of the model of the magnetic field. This sequence of steps is very important since, as the results of our study have shown, students who merely followed conventional lessons on the magnetic field and had already completed the first round of a qualitative approach to magnetic and electromagnetic phenomena have considerable difficulty in using the fundamental properties of the magnetic field.