Scaffolding the structure of organic chemistry students’ multivariate comparative mechanistic reasoning

Problem solving in all sciences requires the integration of multiple causal variables. Organic chemistry students often limit their reasoning about multivariate mechanism problems to single variables. To our knowledge, no teaching instrument that uses the structure of mechanistic reasoning to explicitly foster the consideration of multiple variables has been empirically evaluated to date. To fill this gap, we developed a scaffold based on findings in philosophy of organic chemistry and tested it in a qualitative interview setting. The scaffold provides a stepwise reasoning structure to compare the activation energy required for two different molecules to undergo the same type of mechanistic step. We found that the scaffold builds on what students already do when engaging in comparative mechanistic reasoning by themselves and supports their multivariate reasoning. The applicability of the structure of the scaffold in other contexts of mechanistic reasoning including physics is discussed.