This document discusses pedagogical content knowledge (PCK) for elementary teachers. PCK refers to a teacher's knowledge of how to represent subject matter to students, an understanding of students' misconceptions, and knowledge of topic-specific learning difficulties. The document outlines components of PCK for teaching elementary science and from a constructivist perspective. It also discusses PCK for teaching preservice teachers and notes that PCK has a hierarchy from general science down to specific topics. For elementary teachers, PCK focuses on specific topics rather than whole disciplines. Their foundation for PCK includes substantive and syntactical content knowledge, as well as STEM experiences. Finally, the document distinguishes between espoused/planned PCK