In this self-study, Pamela, a new science teacher educator, adopted Just-in-Time Teaching (JiTT) in the context of an elementary science education methodology course. JiTT is a teaching and learning strategy involving interaction between web-based study assignments and face-to-face class sessions. Students respond electronically to web-based assignments that are due shortly before class. The teacher reads students' submissions just before class and adjusts teaching and learning activities based on the students' online feedback. This study was guided by the research question: How do an instructor's pedagogical content knowledge and classroom practice develop during Just-in-Time Teaching?