Instructor Framing and Incentives Shape Physics Students’ Engagement and Learning Gains from an Inquiry-Based Electrostatics Tutorial on the Method of Images

The method of images (MoI) is a valuable technique for solving certain electrostatic boundary value problems consisting of charge density near conductor(s). We developed and validated an inquiry-based tutorial on MoI to help students learn to identify the problems involving symmetry in which MoI is applicable and then apply it by finding the correct image charge configuration. We implemented the inquiry-based tutorial accompanied by pretest and posttest, across three instructors’ classes to evaluate student learning. We also conducted think-aloud interviews with advanced physics students, which helped us gain insights into their problem-solving strategies, evaluate their understanding developed through the tutorial and make necessary refinements to the MoI tutorial. The study identified common student difficulties, which were subsequently integrated into the inquiry-based tutorial as a guide to provide support to students. One important finding is that advanced students have common difficulties related to physics concepts similar to those found in introductory physics courses. The performance difference in the pretest administered after lecture-based instruction and the posttest administered after working through the tutorial reflects students’ ability to apply what they learned from the inquiry-based tutorial compared to traditional lecture. Another important and unanticipated finding of this study is the potential impact of the framing of the inquiry-based tutorial and accompanying tests by one of the instructors on the engagement and performance of students. In particular, the instructor of one of the classes offered students a small amount of extra credit for engaging with the inquiry-based tutorial and tests, explicitly noting that these activities were not part of the current course syllabus and were primarily conducted to support physics education research. This kind of framing likely influenced students’ motivation and engagement, which underscores how the way the instructor frames the inquiry-based instructional tasks to their students can have a significant impact on student performance. Overall, this iterative multi-year design-based comparative research with mixed-method triangulation provides valuable insights on the challenges involved in such studies that educators and researchers alike can greatly benefit from.