The model underlying the simulation is visible, manipulable, and represented in a form that easily connects with the students' theoretical understanding.
Students construct their own models to explain the behavior of the system.
We created and tested a prototype in June, 1995. The results of this test led us to believe that merely allowing students to view an underlying model was not enought to get them to trigger a modeling process. Further testing of students actual performance solving modeling problems suggests that students have difficulty determining the boundaries of the system to be modeled, as well as difficulty with dynamic quantities such as volume vs mass flow. In this screen the student can edit the physcial prameters of the system, either numerically or by dragging pieces in the picture. In this screen the student links the equation pieces to attributes of the system, chooses a specific pump to place in the system and solves the equations.