Explicit teaching of problem categorisation and a preliminary study of its effect on student performance – the case of problems in colligative properties of ideal solutions

Abstract

Research in science education suggests that the way knowledge is organised affects its availability for problem solving. It also constitutes the important difference between experts and novices. The retrieval of learned schemata from long-term memory is facilitated by categorisation of the problem. In this work, first we suggest a categorisation scheme for problems in the special topic of colligative properties of ideal solutions. Secondly, we report on the results when such a scheme was taught to an experimental group (n = 41) of eleventh-grade upper secondary students (age 16-17) in Greece. The group was reduced by considering only students who demonstrated knowledge of the categorisation scheme (n = 24), and was compared with a control group (n = 26) who were taught in the traditional manner. The experimental group showed a superior performance, but it was not statistically significant. Next, we divided the students into high-, intermediate- and low-achievement subgroups on the basis of their performance in two nationally-examined chemistry courses. No differentiation was found for the students of high and low performance. However, in the intermediate subgroup, students of the experimental group outperformed those of the control group. Because of the limitations (mainly small samples) in the research study, the findings should be treated as preliminary ones. The implications for teaching are discussed. [Chem. Educ. Res. Pract., 2006, 7 (2), 114-130]