Developed at the University of Washington and the Ambitious Science Teaching Project, Studio Days are a form of job-embedded professional development that take place during a school day. School teams develop a vision of “what is possible” in instruction and to take principled risks with practices. Multiple role-actors (classroom teachers, coaches, administrators and researchers) collaborate to provide real-time feedback within current lessons. Although Studio Days feature a wide variety of science content, the goal of each science studio day is the same: to support students in improving explanations, models and arguments of scientific phenomena. Prior to the studio the MSTF advisor and mentor will help facilitate a common planning meeting with teachers from a school; they design a unit of instruction and lessons to be used for the following studio day. On the day of the studio, teachers and others attending studio days engage in multiple rounds of co-planning, co-teaching, and co-debriefing.