A major challenge in preparing elementary teachers to teach inquiry-based science is finding qualified mentor teachers who use research-based approaches to teach science in their classrooms. This situation means preservice teachers often see few connections between the research-based principles for teaching science they learn in university-based coursework and the science teaching practices they see in their classroom field placements. We attempted to resolve this situation by creating opportunities for preservice and mentor teachers to learn together. We developed colearning tasks where preservice and mentor teachers collaborated to apply principles of science inquiry and equitable learning to analyze and modify common elementary science curriculum materials. We borrowed from the field of ecology to develop an edge effects framework that enabled an analysis of when and how preservice and mentor teachers connected principle- and practical-based discourses while engaged in the colearning tasks. Our findings suggest that the colearning tasks supported preservice and mentor teachers in connecting research-based principles to practical classroom contexts. However, working on these tasks together was sometimes challenging for both preservice and mentor teachers. We discuss the affordances and constraints of the colearning tasks and the framing of the principle-practical divide as an edge rather than a gap.