Abstract

This article presents a cognitive map proposed to be associated with understanding of the “system concept,” one component of the physics principle of Newton's second low. A definition of the concept is followed by the results of a problem‐solving experiment designed to investigate whether or not good problem solvers possess cognitive structures similar to the one proposed. Think‐aloud protocols were collected as subjects solved a series of physics problems involving Newton's second law. Coding schemes were used to analyze these protocols and to develop a quantitative index intended to reflect the extent to which subjects possessed certain components of the proposed structure. This index proved a highly significant predictor of performance on Newton's second law transfer problems contained in a written exam. In contrast, performance on a set of familiar problems in the same written exam was not a good predictor of performance on transfer problems. These results indicate that cognitive structures that connect the equation ΣF = ma and the concept of choosing appropriate systems are at least part of what constitutes understanding of the principle of Newton's second law. Implications for physics education and problem‐solving research are presented.