Knowledge base and models of teacher education

What must a teacher know? More than the subject, certainly: how children learn, how to explain, how to manage a class, and what the curriculum intends. Shulman called the blend of subject and teaching method pedagogical content knowledge — knowing not just the topic but how to make it understandable. Worked example: a physics teacher who knows Newton's laws (content) and also knows that pupils commonly think a moving object needs a constant force (a misconception to address) has pedagogical content knowledge.