Current reform in science education calls for teachers to understand student thinking within a lesson to effectively address students' needs (NRC in A framework for K-12 science education: practices, crosscutting concepts, and core ideas. National Academy Press, Washington, DC, 2012; NRC in Guide to implementing the Next Generation Science Standards. The National Academies Press, Washington, DC, 2015). This study investigates how to scaffold preservice teachers with learning to attend to students' thinking for the purpose of guiding curricular decisions. The study focuses on one team teaching a science unit during their early field experience. We sought to understand how participants' thoughts and abilities changed through participation in a moderated community of practice using video of their own teaching as a reflective tool. We examined how these changes affected both their classroom practice and their decision-making for future lessons. Evidence shows growth in participants' ability to identify opportunities to elicit, assess, and use students' thinking to guide instructional decisions. Implications for use of the approach used in this study to begin developing novice teachers' pedagogical content knowledge for teaching science are discussed.