This activity focuses on getting students to think about bacteria, water quality and water treatment processes. Students develop and test their hypotheses about the "cleanliness" of three water samples prepared by the teacher. Then they grow bacteria in Petri dishes from the water samples. They learn how private septic systems and community sewage and wastewater treatment plants work, the consequences to the surrounding environment and wildlife from human wastewater, and what measurements of the released "clean" water are monitored to minimize harm to receiving rivers and lakes.

Contamination in drinking water sources or watersheds can negatively affect the organisms that come in contact with it. The affects can be severe causing illness or, in some cases, even death. It is important for people to understand how they can contribute to the contaminants in drinking water and what treatment can be done to counter these harmful effects. Students will learn about the various methods developed by environmental engineers for treating drinking water in the United States.

Students develop an understanding of visible air pollutants with an incomplete combustion demonstration, a "smog in a jar" demonstration, building simple particulate matter collectors, and exploration of engineering roles related to air pollution. In an associated literacy activity, students learn basic marketing concepts and techniques, and the principles of comparative analysis, while creating an advertisement for a hybrid vehicle. Note: You may want to set up the activities for Air Pollution unit, Lessons 2 and 3, simultaneously as they require extended data collection time and can share test sites.