Describes a simple way to demonstrate the principles involved in a drinking water plant. This demonstration developed for a general public lecture can be used in chemistry and biology courses for an ecological and environmental emphasis. (HM)

Examines two instructional strategies, the traditional and learning cycle approaches, and compares them with regard to the variables of sequence, format, and necessity. Concludes that students exposed to the laboratory and discussion type had higher test scores than those in the lecture or reading groups. (Author/RT)