Organizing energy instruction around the work and energy relation to support knowledge integration in secondary physics

Energy is a central idea in physics, but students often learn energy as a set of loosely connected terms, equations, and conservation statements rather than as an integrated explanatory framework. Prior physics education research (PER) has shown that students have persistent difficulty identifying appropriate systems, tracing energy changes across systems and forms, and applying energy conservation in unfamiliar contexts. Drawing on the knowledge integration perspective and on research on systems-based energy reasoning, this study developed a conceptual framework for a ninth-grade energy unit in which the work and energy relation served as the central organizing relation linking energy change, energy conservation, and contextualized problem solving. We implemented a conceptual-framework-based instructional intervention and compared it with regular textbook-sequence instruction in a quasi-experimental study involving two intact ninth-grade classes in China. Both groups studied the same curriculum content for the same amount of instructional time and were taught by the same teacher. Analysis of covariance showed that, after controlling for pretest performance, the intervention group significantly outperformed the control group on the overall post-test score and on the three conceptual categories of energy change, energy conservation, and the work and energy relation. Statistical mediation analyses further showed that the intervention group’s post-test advantage was associated with students’ performance on the work and energy relation. In the post-test mediation model, this indirect association was larger for atypical context performance than for typical context performance. These findings provide classroom-based evidence that reorganizing energy instruction around a core conceptual relation can support students’ integrated understanding and application of energy ideas. The study contributes to PER by extending conceptual-framework-based instruction to a broader secondary energy unit and by clarifying how a work-centered organization may support reasoning beyond familiar surface features.