An Interactive Simulation to Evaluate Student Understanding of Moon Phase Formation

The development of student understanding of phases of the moon is notoriously difficult due to the spatial reasoning requirements posed by the relative motion of three celestial bodies. We have used the Greek version of Physics by Inquiry to develop two alternative three-body models with a class of prospective elementary teachers. At the end of the semester we used a computer-based evaluation instrument that we developed in order to assess student understanding of the formation of the phases of the moon as well as the evidence on which students base their models. In this paper, we discuss the design of the simulation software and the interpretation of the assessment results we obtained in the context of this application.