Pedagogic Content Knowledge that is knowledge of the subject being taught, and pedagogic knowledge, that is knowledge of how to teach (i.e. planning, assessment, etc).
Despite a teacher's deep understanding of a subject area s/he must also be able to foster understanding of subject or concepts for students. Shulman (1987) calls this pedagogical content knowledge. Pedagogical content knowledge includes
. . . the most regularly taught topics in one's subject area, the most useful forms of representation of those ideas, the most powerful analogies, illustrations, examples, explanations, and demonstrations - in a word, the ways of representing the subject that make it comprehensible to others. . .(I)t also includes an understanding of what makes the learning of specific topics easy or difficult: the conceptions and preconceptions that students of different ages and backgrounds bring with them to learning. (Shulman, 1987 p. 9)
Pedagogical content knowledge is grounded in the beliefs and practices of the teacher. It also includes conceptual and procedural knowledge, a repertoire of varied techniques or activities (which meet different learning styles or preferences) knowledge of techniques for assessing and evaluating, and knowledge of a variety of resources which can be easily accessed for use in the classroom. Pedagogical content knowledge "represents a class of knowledge that is central to teachers' work and that would not typically be held by nonteaching subject matter experts or by teachers who know little of that subject". (Marks 1990, p. 9)