Engineering representations guide student problem-solving in statics

Background: Engineering students inconsistently apply equilibrium when solving problems in statics, but few studies have explored why. Visual cognition studies suggest that features of the visual representations we use to teach students influence what domain knowledge they use to solve problems. However, few studies have explored how visual representations influence what problem-solving strategies and domain knowledge students of different levels of expertise use when solving problems that require them to create and coordinate multiple representations. Purpose/Hypothesis: This study addressed the following research question: How do students with different levels of expertise coordinate their problem-solving strategies, problem-solving heuristics, and representation features when sketching their shear force and bending moment diagrams?. Design/Method: We conducted think-aloud interviews while students sketched shear force and bending moment diagrams. These interviews were subsequently analyzed using the constant comparative method to examine the effect of representations on students' problem-solving approaches. Results: Three themes emerged from the data: Students used heuristics that are based on perceptually salient features to sketch their shear force and bending moment diagrams; students across levels of expertise rely on the object translation heuristic rather than equilibrium problem-solving schema to sketch and reason through their shear force and bending moment diagrams, and domain knowledge aids students' ability to resolve conflicting heuristics. Our findings suggest that students primarily rely on heuristics triggered by representation features they notice. Conclusions: Students engaged with shear force and bending moment diagrams not as a way to describe systems that are not accelerating but as a series of representations that “should go to zero” or arrows that make things “not zero.”.