Developing explanatory models is a central practice to scientific inquiry. When students create and test explanatory models for scientific phenomenon, they develop content knowledge, knowledge of the nature of science, and creative thinking skills. Unfortunately, such instruction rarely occurs in K-12 science. This is, in part, because teachers do not have the opportunity to develop sophisticated understandings of the process of modeling, but also because teaching in this way requires teachers to make real-time instructional decisions that are responsive to students' ideas. This is challenging for teachers, especially because this decision process is often invisible. In this talk, I will highlight the importance of providing opportunities for sophisticated science thinking for our youngest learners and consider how uncovering the decisions that shape physics courses for teachers may benefit their future students.