This article and associated formative assessment probe can be used to determine students' prior knowledge and misconceptions about weathering and erosion. Implemented before or during a weathering/erosion unit, it is best used as a tool to determine the necessity for additional instruction. The associated article connects the probe to appropriate NGSS disciplinary core ideas, providing background knowledge on weatheringand erosion for teachers, common misconceptions to look for, and different methods for using the probes with various groups of students.