John Fischer, Ashwaubenon HS, Green Bay, WI, has created an artificial “Two Liter Creek” in his classroom for water quality studies in the middle of a Wisconsin winter. It is simply a 50-gallon aquarium with a pump that lifts water into an array of 15 two-liter bottles that have been mounted on a pegboard. This closed-loop creek has gravel in the bottles and in the aquarium. Over time, the artificial creek forms an ecosystem, as does a real creek. John’s students become experts at using our sensors to monitor this creek and they are ready to tackle the outdoor water when spring comes. The students have even intentionally “polluted” the creek and monitored its recovery.