The Construction Of Middle School Students' Mental Models Of Atoms And Molecules

Models are frequently used to explain science concepts at all levels of chemistry teaching and learning. Teachers induced the change of students’mental models by a variety of teaching models to make it consistent with the scientific models, thereby contributing to their understanding of the chemical knowledge and the material world. However, little is known about how each student’s mental models interact with the various models presented by teachers and in textbooks. Therefore, exploration of students’mental models are bound up with the model and modeling of chemical education.On the basis of the literature review, this paper pointed out the deficiency of the existing model classification, proposed a new view of model classification, and constructed a structural model of the relationship between different models of chemical science and teaching. In the empirical study, we induced360students of9-11grade to express the mental models of atoms and molecules by semi-structured interviews; Through the analysis of their own mental models, this paper summarized the modeling process of them, and concluded their modeling features, rules and differences; At the same times, We probed the difficulties that students encountered in constructing the model of atoms and molecules, and proposed appropriate teaching suggestions for teachers.The outcomes suggest:(i) students preferred models that are both simple and concrete, their mental model are incompleteness, inaccuracy and instability.(ii) The large number of students hadn’t fully understood the "electron cloud","shells" and "atomic orbital", some of them even produced misconceptions. The root of the mistakes is that the students failed to properly understand the exercise form of extranuclear electron;(iii) the gender had no effect on the construction of atomic mental model, the environment and the teachers are the factors that affected the construction of atomic mental model.