Physics is the study of forces and motion--the science of matter and energy and the interaction between the two. The big idea the children explore, as well as the question they ask as they engage in physical knowledge activities related to physics, is "How does it move?" Many teachers translate naturally as they come to know the children they teach. They use the language and concepts children understand to help them grasp the big ideas. Later, these concepts become more powerful and precise because of these prior experiences. When planning physical knowledge activities, specifically those that focus on physics concepts, DeVries and colleagues (2002) suggest four criteria: (1) Children must be able to produce the movement by their own action; (2) Children must be able to vary their actions; (3) The reaction of the objects must be observable; and (4) The reaction of the objects must be immediate. The goal of these activities is to encourage children's exploration of their own questions and problems that arise during experimentation. What may not always be clear to teachers is the best time or best way to support children's cognitive development during their play. In this article, the authors share examples of teachers' roles in supporting children's inquiry by focusing on the process of problem solving and the content of physics.