In a teacher professional development meeting, teachers were asked a question about potential energy and then to discuss why students might give a particular response to it. Working together in a large group, they came up with responses and explanations that touched on multiple ways of thinking about energy and how these might affect student responses. We observed that teachers were aware of common metaphors for thinking about energy (like energy-as-a-substance) and that they gave multiple explanations for how students might have difficulties in applying these metaphors (e.g., energy is "used up" because of travel time, travel distance, or the effort exerted during travel). Additional explanations showed that teachers recognized how students might bring these ideas to the classroom. We discuss the need for teachers to respond to multiple grain sizes of student thinking, including the metaphors they use and the different facets of each. Assessments that help with this will be of greater value to teachers than the assessment we present.