Shirley Magnusson, Joseph Krajcik and Hilda Borko 4. Nature, Sources, and Development of Pedagogical Content Knowledge for Science Teaching

“What shall I do with my students to help them understand this science concept? What materials are there to help me? What are my students likely to already know and what will be difficult for them? How best shall I evaluate what my students have learned?" These questions are common for every teacher, and central to describing the knowledge that distinguishes a teacher from a subject matter specialist. In this paper, we argue that such knowledge is described by the concept known as pedagogical content knowledge, and that this concept is critical to understanding effective science teaching. We describe pedagogical content knowledge as the transformation of several types of knowledge for teaching (including subject matter knowledge), and that as such it represents a unique domain of teacher knowledge. This chapter presents our conceptualization of pedagogical content knowledge and illustrates how this concept applies to understanding science education from the perspective of the teacher, the science teacher educator, and the science education researcher.