McElhaney, K. W., & Linn, M. C. (2010). Helping Students Make Controlled Experiments More Informative. In K. Gomez, L. Lyons, J. Radinsky (Eds.). Learning in the Disciplines: Proceedings of the 9th International Conference of the Learning Sciences, Volume 1 (pp. 786-793). Chicago, IL: International Society of the Learning Sciences.
We examine how encouraging students to compare rather than isolate variables affects their experimentation strategies and insights. We designed a week-long, technology-advanced inquiry model on car collisions that logs student’s interactions with a visualization. Physics students (N=166) were assigned to conditions that prompted them either to isolate or compare variables. Students responded to pretests, post tests, and embedded prompts that assessed student’s understanding of motion graphs and collisions. Both groups made significant pretest to post test gains. Students in the compare treatment used more diverse experimentation strategies than students in the isolate treatment. Compare students made nuanced interpretations of collision events based on threshold values. Case studies illustrate how comparing rather than isolating helped students use wide-ranging strategies to reach complex insights. The findings illustrate the value of encouraging multiple approaches to experimentation and connecting experimentation to real-life contexts.