A research programme for the improvement of science teaching is described, exemplified, and discussed. Briefly, the idea of the programme is that researchers in science education and teachers in schools should work together to design teaching sequences and to assess how they function in practice. Research results concerning pupils’ everyday conceptions, as well as analyses of the conceptual structure of a given area and the reasons for teaching it, play an important role when working on a design. The most important product of the design phase is a detailed guide for teachers, which we look upon as a tool for further knowledge-building. In our paper we suggest that the idea of domain-specific theories is worth examining and developing. It might contribute to strengthening science education as an autonomous discipline.