Ninth grade students at two different schools worked on the same conceptual questions about freely falling objects. This chapter presents the first of two case studies about what happened. In this case study, Matt Reese analyzes his students' written responses to the questions. It is recommended that participants start by reading only the introduction to Matt's case study, containing the background information about the class and the question set. Then spend some time looking through the student work before continuing with the rest of Matt's account. This gives participants a chance to interpret the students' responses for themselves, before reading Matt's interpretations.