| One important goal of physics education is to help students develop reasoning patterns similar to those of expert physicists. To achieve this goal, physics educators must know what makes physics experts so successful at solving challenging physics problems. However, this dimension of physics expertise has not been fully explored by the physics education research (PER) community. In this dissertation, I describe several studies I have conducted that further the PER community's understanding of physics expertise. In these studies, I investigate how expert physicists reason as they solve unfamiliar, challenging physics problems by using a resource-based model of cognition to analyze videotaped recordings of problem solving sessions. By developing a way to determine when experts are making conceptual breakthroughs I analyze what resources experts use during conceptual breakthroughs. In the first study, I show that physics conceptual breakthroughs are characterized by reasoning which combines resources related to intuitive knowledge, higher level physics based conceptual knowledge, and epistemological knowledge. In the second study, I develop a way to reliably code for epistemological resources and determine what epistemological resources experts rely on most during conceptual breakthroughs. My findings show that experts rely on contrasting cases more often than any other epistemological resource. In the third study, I use variation theory to investigate how experts use contrasting cases. I look for patterns across all instances when experts use contrasting cases to make a conceptual breakthrough and show how scientific epistemology can be used to better understand experts' use of contrasting cases. I discuss how the findings of each study can be used to inform physics education. |
