This paper details a model of teacher development that allows students to demonstrate their understanding of basic astronomy concepts as well as communicating that understanding in creative ways. Key features of the model include starting from students' initial understanding about astronomical concepts and providing time for students to assess first their mental models and then their astronomical understanding, in both cases using 3-D models. These key features appear collectively to provide an appropriate creative environment for students. Two students adapted their original 3-D models in order to communicate specific aspects of seasons - different solar inputs and varying lengths of day/night throughout the
year. Interviews of the two students highlighted the thinking that led to the creation of the new components. The uptake by other students, during the modeling assessment task, demonstrated the effectiveness of the new components in communicating an astronomical understanding of seasons. The model of teacher development illustrates how teacher educators can teach for astronomy understanding as well as allow for creative ways to communicate that understanding to others - an essential aspect of being an effective astronomy educator in the classroom.