Ihlara Journal Educational Research

Abstract

This study presents an instructional design for the phase-based use of molecular models in teaching the concepts of physical and chemical change. The design includes an activity based on two phases and two sample cases in each phase. The design addresses the changes taking place at different levels in chemistry education. These changes are; melting of ice, evaporation of water, formation and decomposition of water. It is aimed to progressively draw attention to how to interpret the molecular model representation by giving the properties of the physical or chemical change that can be obtained by observation or experimentation. The instructional design can be reorganized for traditional teaching approaches and is responsive to many current approaches. At this point, in order not to make a limitation, only the phase-based nature of the design is emphasized. For this reason, the question-answer technique, which is the most common technique used by teachers in the teaching process, and discussion opportunities to some extent were highlighted. In this context, eight problems with their solutions are given to determine whether each molecular model's representation reflects the given properties. It is thought that the design will guide the teaching of physical and chemical changes in a substance at the secondary school, high school or undergraduate level through representations (molecule models) at the particle level. Besides, it is possible to use this study in teaching the properties (conservation of mass, atomic type in the molecule and the conservation of the number of each atomic type) in chemical change through the proposed representations.