Abstract:

The aim of this study is to investigate high school students’ cognitive structures and to identify their learning difficulties in physical and chemical changes through word association test (WAT) and to compare at different students grades. The study was comprised of 167 students who are attending at ninth (88 students) and tenth grades (79 students). The WAT was used as data a collection instrument developed by the researcher. Before WAT is developed, the physical and chemical change topic placed in high school chemistry curriculum was examined to select the stimulus words of WAT. The WAT comprised of eight total stimulus words, among them chemical reaction, energy, chemical property, and   physical property, is used to probe students’ cognitive structures. At the end of the study, it was found that differences in the students’ cognitive structures at ninth and tenth grades make it clear that instruction affects the cognitive structure. On the other hand, it was also concluded that students from both grades cannot associate with the concept of energy with other concepts of the subject.

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