Andrew Heckler Ohio State University Department of Physics How diagrams help and hinder problem solving This study examines student construction and use of diagrams and equations to solve traditional physics problems. Student responses are studied under two conditions: when diagrams are or are not explicitly required. Results indicate that requiring diagrams can help students by leading them to more abstract and formal solution paths, but can also hinder performance by focusing attention on a single solution path, even if incorrect, limiting their ability to consider alternative solutions. Requiring force diagrams also compels students to depict incorrect concepts involving force more frequently in their diagrams. When diagrams are not required, students tend to draw them nevertheless and tend to depict only the concrete and salient features of the stated problem. In turn, these students tend to follow solution paths based on these concrete and physically intuitive features. Finally, diagrams are found to be more consistent with the students' equation paths when diagrams are not required, indicating that the extent to which student-produced diagrams or equations reflect student understanding depends on the task required.