Discusses a laboratory exercise simulating the paths of light rays through spherical water drops by applying principles of ray optics and geometry. Describes four parts: determining the output angles, computer simulation, explorations, model testing, and solutions. Provides a computer program and some diagrams. (YP)

Discusses the missing water on Mars. Describes five experiments simulating conditions on Mars: (1) behavior of dry ice; (2) low-pressure vacuum; (3) freezing point depression; (4) water in hydrated minerals and clay; and (5) properties of carbon dioxide. (YP)

Presents research results on photosynthetic, carbon monoxide utilizing bacteria. Discusses applications of the research and offers three sets of experimental procedures and data that students analyze to determine which bacterium from a soil sample uses carbon monoxide fastest. (Contains 21 references.) (MDH)

This article reports the adoption of new policies to restrict experiments on animals in the elementary or secondary school classroom. The controversy involving animal welfare groups is discussed as it relates to animal abuse by students. (SA)

Provides a running commentary on a chemistry instructor's first day in a first course in chemistry. Focuses on the use of fire and chemists' attempts to explain this phenomenon. Provides the ongoing descriptions of the experiments, a summary of the observations, and the key comments made by the instructor. (TW)