March 2010: Following the three major snow storms which occurred in the Baltimore region from December 2009 to February 2010, students examined data collected by BES Technician Dan Dillon from the same stream data classes had investigated in December. Through comparison of the data sets over several months, students discovered that Conductivity levels had sharply increased to values thousands of times greater than what they had found in the December 2009 “pre-blizzard” values. A hands-on activity students conducted as part of the March 2010 lesson included a simulation of point-source and non-point source pollution inputs resulting from hypothetical human activities which would be expected to occur along an urban or suburban waterway. In this activity, a clear, three-gallon container of water was placed at front of the classroom. Each student was given a small sample of a simulated substance that could reach a local stream as a result of nearby human activities. Ten different 2 oz simulated samples were prepared and sealed inside a 35 mm film canister. The samples were labeled so students knew in advance of the contents. To add an element of “change” to each, different amounts of “Blizzard Wizard” road salt (containing mostly KCl) was added, ranging from a trace to 2 teaspoons. This substance was added to include the road salt run-off component. The simulated samples ranged from diesel oil, gasoline and home insulation fiber to cigarette butts, waste solid food and beverages. Each time a student poured their simulated polluting substance in the water container, a Vernier Conductivity Meter and TI-83+/Lab Pro recorded change in the Conductivity levels. The student also read to the class a three sentence description of the situation which led to the substance being deposited in the local waterway. In each case, the human activities were presented as realistic actions that people have carried out. Examples included hikers throwing waste food and cigarettes in a stream, a suburban homeowner dumping waste oil or acute runoff from a salt pile in a roadway. At the conclusion of the activity, after ten different substances had been deposited in the simulated waterway, students were able to see that the Conductivity levels of the waterway, at approximately 3,000 microsiemens, were notably much higher than even their favorite sports drinks, observed at 600.