This short video (3:13 minutes) introduces complex adaptive systems and agent-based modeling concepts to middle-school students. It shows beautiful footage of birds flocking as an example of a complex adaptive system.
A portion of a PBS NOVA video discussing the concept of emergence (or complex adaptive systems) where patterns emerge in nature where agents follow simple rules.
This is an example of how a computer modeler uses various aspect of computational thinking while designing, creating and using a computer model as a tool to think with.