Video: From the Soil
And on to grades 6-8:
In grades 6-8, students can understand that systems may interact with other systems; they may have sub-systems and be a part of larger complex systems. They can use models to represent systems and their interactions—such as inputs, processes and outputs—and energy, matter, and information flows within systems. They can also learn that models are limited in that they only represent certain aspects of the system under study.
—Next Generation Science Standards, Crosscutting Concept 4
Lesson idea: Show From the Soil. Then develop the balancing and reinforcing loops and the stock and flows model as described in the background essay and activity. Ask students to consider: