  Detailed investigations of student reasoning show that students approach the
topic of wave physics using both event-like and object-like descriptions of
wavepulses, but primarily focus on object properties in their reasoning.
Student responses to interview and written questions are analysed using diSessa
and Sherin's coordination class model which suggests that student use of
specific reasoning resources is guided by possibly unconscious cues. Here, the
term reasoning resources is used in a general fashion to describe any of the
smaller grain size models of reasoning (p-prims, facets of knowledge, intuitive
rules, etc) rather than theoretically ambiguous (mis)conceptions. Student
applications of reasoning resources, including one previously undocumented, are
described. Though the coordination class model is extremely helpful in
organising the research data, problematic aspects of the model are also
discussed.
