The relation between the control-of-variables strategy and content knowledge in physics in secondary school

Abstract

The control-of-variables strategy (CVS) is considered a hallmark in the development of scientific reasoning. It holds that informative experiments need to be contrastive and controlled. Prior evidence suggests that CVS is connected to the acquisition of science content knowledge. In a cross-sectional study involving 1283 high school students (grades 5–13), we investigate whether students’ mastery of CVS is related to their science content knowledge in physics. A latent variable model indicates that CVS is substantially associated with students’ science content knowledge, even when controlling for common effects of general reasoning abilities. Substantial differences in students’ CVS skills and their science content knowledge exist between the lower grade levels in secondary school when students receive physics education. A latent profile analysis shows that the most difficult aspect of CVS is understanding the impact of confounding. This sub-skill emerges in late secondary school and it requires that students master more procedural sub-skills of CVS. These findings indicate that CVS and science content knowledge are closely related within secondary school science contexts. In addition, the findings emphasize that students show various distinct patterns of CVS skills. The identified skill patterns can inform researchers and science educators about the CVS skills that students typically show and thus can be utilized in inquiry activities in different school grades, while the CVS skills students are lacking might be trained in focused interventions.