In this lesson, students will become familiar with the Water Pumping base model. Students will (1) review math basics necessary for understanding the model, (2) decode the base model, run simple experiments, make observations, and identify complex systems characteristic of the model (3) add an evaporation slider and run an experiment, using the slider, and (4) finally, be asked to think of ways to improve the model, based on what they know about the hydrologic cycle and water as a resource.