Challenging models of elastic collisions with a computer simulation

A number of techniques were used to elicit 16–17 yr old physics students' understanding of collisions. The students appear to use two different models of reasoning, namely a linear causal and a resistance/reciprocal causal model. These models however break down when the students are confronted with a computer simulation, if conservation of energy is not understood. The computer simulation allows pupils time to run experiments which they think will confirm their faulty models but which facilitate a shared understanding of energy conservation