Plate tectonics is the organizing paradigm of geosciences, but it is also conceptually complex, and students often struggle with developing a system level understanding of the earth. This article reports on research designed to create a characterization of the different levels of sophistication around plate tectonics in the form of a learning…

This study describes the process of defining a hypothetical learning progression (LP) for astronomy around the big idea of "Solar System formation." At the most sophisticated level, students can explain how the formation process led to the current Solar System by considering how the planets formed from the collapse of a rotating cloud of…