  We are interested in better understanding ways that students collaborate to
solve conceptual physics problems in the context of spherical unit vectors in
upper-level E&M, especially problems that have been shown to be difficult for
students to solve individually on their own, but which groups of students have
been more successful at. Using think-aloud interviews with students in small
groups, we ask them to solve together on a large whiteboard conceptual problems
from this E&M context. The interviews were video and audio recorded, and
qualitatively analyzed using an emergent coding method and the resources
framework. Through this analysis, we observed one common mechanism in all three
group-interviews whereby students collaborated effectively: first one student
activated a conceptual resource and expressed it, then another student took up
that idea, and finally the whole group together used that idea to move forward
with the problem. This mechanism exemplifies a newer framework: shared
resources. We further analyzed students' collaboration through the lens of
shared resources and identified multiple instances. We propose that the shared
resources construct could be a potential tool to help understand how students
collaborate in solving conceptual physics problems. In this paper, we report
our methodology and the results from one group interview to illustrate one
shared resource we identified and the role it played in helping students
collaboratively solve the conceptual problem in this context. Future work and
implications for instruction are suggested.
