In this study subjects worked with a computer simulation (on the physics domain of oscillation) in which two supportive measures were used: model progression (gradually increasing the simulation model in complexity) and assignments (small exercises). In measuring results of learning from the simulation environments, special attention was given to assessing intuitive knowledge as compared to definitional knowledge. Three experimental conditions were created that differed with respect to the supportive measures available: one group of learners used both model progression and assignments, one group was only supported with model progression, and the third group was provided with neither model progression nor assignments. The results showed a small gain in definitional knowledge for all three conditions. The gain in intuitive knowledge was considerable and differed across the experimental groups in favour of the conditions in which assignments and/or model progression were present.