As part of the first authorís PhD project, year 9 and 10 students were given a system dynamics model of the impacts of visitors on a National Park. The students were given a pre- and post-test to determine whether their knowledge of the environment changed. Students were randomly assigned to either the individual learning condition (students interrogated the model as individuals) or the collaborative learning condition (students interrogated the model with one other student). There was a significant increase in the environmental knowledge score for those students in the collaborative learning condition, but not in the individual learning condition. The implications of this finding for the use of system dynamics models in educational settings are discussed.