Model-based reasoning in a Year 10 classroom

Studies have shown that secondary school students experience difficulties making scientific models meaningful, yet explanatory models are central to the development of scientific understanding. This study investigated the extent and nature of students' model- based reasoning in a laboratory investigation. It was an interpretive study involving a single Year 10 science class investigating the influence of six factors on electrical resistance. Before commencing their practical investigations students were re- familiarised with the 'electron-drift' model of metals. Data sources included videotapes of classroom interactions, audiotaped interviews with students, student workbooks showing their experimental procedures and results, and explanations of those results. The research suggest that spontaneous use of the model in explanations increased over the duration of the task but that the explanations were restricted mainly to model-based reasoning with lower order relational mapping. Even after further formal instruction on the model after the initial experimental investigations, many students were still unable to use the model effectively, displaying mainly the same level of reasoning. As model-based reasoning is an important part of learning some aspects of science, it is imperative that science educators take appropriate steps to facilitate the development of such reasoning in appropriate contexts.