We present results from a Swedish school development program in science where researchers together with a team of secondary school teachers have worked to accomplish a transformation of epistemic practices, starting from a practice which students using their current experiences can make sense of, and which gives them epistemological agency, into a more scientific one, with more scientific purposes, which to begin with are unfamiliar to the students, but which eventually changes their epistemologies and afford students to learn new content (Wickman & Ligozat, 2011). We worked in cycles where researchers together with the teachers planned and evaluated successive units. We report from two cycles on a unit about nutrients in Grade 8. The planning and evaluations where based on classroom recordings, which were analyzed to jointly situate the theoretical framework in actual classroom consequences, to support teachers in making the practices continuous in action and to see that students were given epistemological agency together with teachers. Our study contributes to how epistemic practices can be organized to support students’ engagement and learning. In our presentation we will give transcripts to support our claims.