We describe a two-year study of a rich secondary science curriculum that was codesigned in close partnership with teachers, technology specialists and even school administrators. The goal of the research was to provide empirical support for a recent model of learning and instruction that blends the two perspectives of knowledge communities and scaffolded inquiry. A design-oriented method was employed, where the first iteration of the curriculum was evaluated in terms of its fit to the model, as well as its impact on student learning. Based on a set of design recommendations, a much more substantive curriculum was developed for the second iteration, leading to rich measures of student collaboration and deep understanding of the targeted science concepts. This paper describes our co-design process, which allowed teachers to lead the curriculum design and classroom enactment while researchers contributed design guidelines according to the theoretical model.