AN INTERACTIVE GROUNDWATER MODEL FOR MIDDLE SCHOOLS

The University of North Carolina at Wilmington has implemented a three-year project, funded by the NSF, to facilitate inquiry-based learning in local middle schools. A select group of science graduate students (GK-12 Fellows) from programs in chemistry, biology, earth sciences, and marine sciences are serving as classroom resource persons for middle school teachers and students. Year 1 focuses on the eighth grade. Using the eighth grade competency goals of the North Carolina Standard Course of Study, hands-on earth science-intensive activities have been developed that promote enthusiasm and awareness of earth systems.

An interactive model has been designed to educate students about the geologic structure and properties of aquifers, the movement of groundwater, and the methods by which geologists recognize point- and non-point sources of pollution. The model was constructed using gravel, bentonite clay, and medium-grained sand. A gravel aquifer lies above a “basement” constructed of pottery clay sealed with Silicon II caulking and is designed to resemble crystalline rock. A basement dipping at 20-30° permits down slope movement of the water. The gravel aquifer is approximately 10 cm thick and composed entirely of 2mm-sized pea-gravel. An overlying 2-3 cm thick clay layer completely confines the gravel aquifer. Above the confining layer sits a 30 cm layer of medium-grained sand. A second discontinuous clay layer interrupts this sand, creating both an unconfined and perched aquifer. Five plastic tubes, sealed at the bottom and perforated with holes near the base, serve as wells permitting students to saturate the aquifers, measure artesian flow in downdip wells, and track acidic “pollutants” throughout the system.