The Influence of Different Models on 15-years-old Students' Understanding of the Solid State of Matter

Different models are an indispensable part of teaching and learning chemistry for students to develop adequate mental models of solid states of matter. The aim of this study was to establish the importance of using physical models (teachers' demonstrations and students' modelling) and virtual models of solid states in the educational process for students' to acquire a better understanding of the crystal structures of substances. First year grammar school students (average age 15.4 years) participated in the study. All students were divided into three groups, depending on what sort of activity involving models was used in the chemistry teaching and learning process. The solid state of matter was taught in the first group by students' constructing physical models. In the second group virtual models were used, while the third group was taught by teachers' demonstration of physical models. Students' understanding of the solid state structures was assessed with a knowledge test after the educational strategy, whereas the knowledge retention was evaluated one month following the applications of the teaching strategies with the delayed test. The students who modelled physical models scored better on the test than did the students who used virtual models and also those who were taught the solid state of matter by the teachers' demonstration of physical models. Those students who used virtual models or modelling during chemistry learning achieved statistically the same results on the delayed test, whereas the students who were exposed to the teachers' model demonstration achieved the lowest test score. It can be concluded that students who are engaged in active learning strategies that include modelling or computer interaction using virtual models develop more adequate mental models of solid state substance structures.