While earning his PhD from the University of Washington Physics Education Group, he researched student learning of linear momentum, angular momentum, and rigid body dynamics. His current research interests are in the application of conceptual metaphor, embodied cognition, interaction analysis, and history and philosophy of science to learning about physics and about physics teaching. Presently he is pursuing these interests in the context of the Energy Project at Seattle Pacific University, the purpose of which is to study and support the learning of energy and the development of teachers' proximal formative assessment skills for energy. He also runs the Physics Learning Assistant Program and has developed the Physics Interview Project at SPU.