Building on dual-space theories, the three-space theory of problem solving suggests to add search of a model space in addition to search of experiment and hypothesis space. This study aimed at exploring the three postulated spaces, especially model space, by means of verbal protocols. Participants (n=32) were asked to think aloud while working with a computer based learning program. With this program they could learn about torques in physics using interactive graphics in which experiments could be conducted. Their knowledge about torques was tested before and after working with the program. Verbal protocols were analyzed with regard to the amount of search of the three spaces and regarding the quality of the participants’ models for torques. Our results add to the validity of model space, showing that the three postulated spaces could be reliably identified in the protocols and that the model quality score predicted final knowledge beyond prior knowledge.