Students' ability to explain phenomena were compared when they were provided a model versus asked to draw their own model. As part of a pilot test, 1,405 students in the fourth through twelfth grades from across the United States responded to one of three different modeling tasks. Each task presented students with a phenomenon related to energy and asked them to either draw a model or use a provided model to explain the phenomenon. Students were then prompted to write explanations of the phenomenon and answer several multiple-choice questions assessing their knowledge of the topic of energy. Students' explanations, drawn models, and responses to the multiple-choice questions were then scored and compared. Our results indicated that students who were provided a model wrote better explanations than students who had to draw their own model, and that students' drawn models added little to their explanation that wasn't captured in their written responses. When comparing students' drawn models, we found that students who drew the most sophisticated models had significantly more understanding of the energy concept then students who drew the least sophisticated models.