| Matter & Interactions, an innovative introductory physics curriculum developed by Ruth Chabay and Bruce Sherwood, emphasizes computer modeling and fundamental physical principles. Two think-aloud protocol studies were conducted to investigate the performance of students from this curriculum in solving physics problems that require computer modeling. Experiment 1 examined whether Matter & Interactions students would, given the choice, use computer modeling to solve difficult problems that required predicting motion, and how their solution approaches differed from those of students from a traditional introductory physics course. Though they did not overwhelmingly choose computer modeling, some M&I students did write computer models successfully or apply the iterative algorithm by hand. The solution approaches of M&I students and traditional course students differed qualitatively in their use of the momentum principle and pre-derived special case formulas.; In experiment 2, Matter & Interactions students were observed while they wrote programs in the VPython language in order to examine their difficulties with computer modeling. Areas of difficulty included determining initial conditions, distinguishing between simulated time and the time step, and updating momentum and position. Especially troublesome for students was the multistep procedure for calculating a force that changes with time. Students' understanding of the structure of a computer model improved by the end of the semester as shown by their performance on a line sorting task. Students with fewer difficulties proceeded through the computer model in a more linear, straightforward fashion. Instruction was revised based on initial findings from the first phase of the experiment. Students in the second phase of the experiment, who had used the revised instruction, had fewer difficulties on the same tasks, though other factors may have been involved in the improvement. |
