Please note that this is an assessment tool and not a unit lesson plan. Performance expectation 5-LS2-1 is in two parts. As we were developing our formative assessment and summative task, we thought about teaching the learning performance sequentially and decided these spots would be a good place to check in for student understanding. Our thinking of a model is a representation and explanation of a phenomenon. You may want to choose the format your students create (flow chart, drawing, plus/delta, etc.) There are several templates in the formative and summative assessments that may help you and your class.