Presented is an exercise for high school students which illustrates the principle and practice of measuring energy flow through a community. Included are worksheets, instructions, a flow diagram, and a list of ecosystem parameters. (Author/CW)

Described are three experiments on the photometric, Gaussian, and image-forming properties of a helium-neon gas laser. Details of the experimental method and typical calculations with diagrams and graphs are provided. (YP)

Four questions related to rain concerning aerodynamic drag force, pressure from the impact of raindrops, impact of wind on the pressure, and stopping force extended on the car by the water are proposed. (YP)

Described are several physics activities developed by a high school: research corner, exploring an invention, construction projects, archives report and archives update, short term research and design projects, essay contest, and special projects. (YP)

This was an experiment to test the extended discretion laboratory approach versus a guided-inquiry approach for teaching biology in a university setting. Among three criterion variables (examination, reports, and quizzes), only the laboratory report scores showed differences between groups and group-by-instructor interaction. (Author/YP)

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)

Discussed is the historic development of Snell's law and derivation of the law without using mathematical expressions. Describes laboratory procedures using diagrams. (YP)

Describes exercises in which tabs from aluminum beverage cans are used to introduce principles of classification, biostratigraphy, and evolution. Provides diagrams which represent dorsal and ventral views of species and a table which graphs units of time in relation to species duration. (RT)

Described is a laboratory study designed to demonstrate loss of vegetation, alterations in the species composition of a community, and the impoverishment of a community with respect to desirable food plant species when herbivore feeding exceeds the rate of vegetation regrowth. The laboratory uses a classroom aquarium. (CW)

Contained in this issue is a variety of creative crafts involving nature. Each of the 17 ideas contains directions, a list of materials, and an illustration of the finished craft. A final section lists different craft books and includes an index to NatureScope and Ranger Rick crafts. (CW)

Described is an experiment for measuring the coefficient of restitution with a meter stick, balls of different types, and scraps of material for the plates. Provides the experimental procedure and an apparatus diagram. (YP)

Describes principals of physics that are manifested in simple biological systems of heat conservation structures. Outlines materials needed, data collection, analysis, and discussion questions for construction and operation of two models, one that is a countercurrent heat exchange model and one that is not. (RT)

Describes teaching ecology by using highway travel. Provides an outline for the travel observation checklist. Discusses some practical information for using the activity. (YP)

Discusses an astronomy simulation activity introducing the concepts of rotation, revolution, and retrograde motion. Describes the activity procedures in classrooms. (YP)

Presents a treasure hunt activity done as a culmination of a discussion of animal languages concentrating on visual, auditory, and chemical messages. (MKR)