High school teachers who agreed to participate in the study met briefly with faculty researchers during the previous summer to discuss the approach and guidelines for its implementation. All of the physics classes were selected to be non-advanced algebra-based courses (for example, advanced placement courses were avoided due to their inflexible schedule). During the fall, the teachers were provided with various materials: example problems using the CPS manipulation, a poster to be used to illustrate the structure of mechanics topics, and tests to be given at the end. The first two authors observed each teacher at least once during each physics topic (3-4 times) and maintained weekly e-mail communication.