In this four-lesson unit, students collect evidence to construct explanations that rain causes changes to their school yard. They develop models to explain rapid and slow changes to the school yard, and observe these changes at a broader watershed level. Finally the students apply the information to an engineering problem where they use their model to develop a solution that will slow down or stop rainwater from changing their school yard.

In this lesson, on the fourth day of the unit, students develop a model to explain that water flow causes different changes to various surfaces on the school yard, and there are patterns in the changes they found. Students also analyze data to figure out that changes to the land can occur rapidly and more slowly. Students will investigate, make observations, and construct scientific claims of slow vs. rapid changes made to the Earth. Students deepen their thinking about the phenomenon of water flow and systems interactions between the hydrosphere (water and weather), the biosphere (plants and insects), and the geosphere (soil, surface materials, and rocks). They are using the relationships they found between the water flow and changes to the earth materials to apply the concept of temporal scales (a few minutes vs. many years).