Fourth-Grade Writing Case: UnpackingThe fi rst example comes from a fourth-grade classroom that was in the middle ofa science unit studying force and motion using the Science and Technology forChildren (STC) Motion and Design unit (NSRC, 2003). Ms. Robinson decided todevelop a writing prompt as a formative assessment to go along with a scientifi cinvestigation focused on how the size of the force impacts the motion of a vehicle.She was interested in assessing her students’ understanding of the force and motionconcepts, as well as their ability to justify their claims with appropriate evidence andreasoning. Specifi cally, the investigation aligned with the fi rst half of the contentstandard in Table 6.2 from the Benchmarks for Science Literacy (AAAS, 2009): The