This paper explores the role that technology can play in engaging pre-service teachers with the iterative, "messy" nature of model-based inquiry. Over the course of 5 weeks, 11 pre-service teachers worked in groups to construct models of diffusion using a computational animation and simulation toolkit, and designed lesson plans for the toolkit. Content analyses of group discussions and lesson plans document attention to content, representation, revision, and evaluation as interwoven aspects of modeling over the course of the workshop. When animating, only content and representation were heavily represented in group discussions. When simulating, all four aspects were represented to different extents across groups. Those differences corresponded with different planned uses for the technology during lessons: to teach modeling, to engage learners with one another's ideas, or to reveal student ideas. We identify specific ways in which technology served an important role in eliciting teachers' knowledge and goals related to scientific modeling in the classroom.