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)

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)

Discusses and suggests some solutions for three problems related to chemistry laboratory management, including disappearance of teaching assistants, check in/out procedures, and slow students. (YP)

Explores a way of analyzing laboratory activities that can help middle and high school science teachers to match their instructional goals with one of three appropriate types of activities: confirmation, generalization, or resolution. Examples and guiding principles for each kind of activity are given. (Contains 23 references.) (MDH)

This photosynthesis exercise is intended for introductory college biology or botany courses. It is based on the principle that a closed suspension of algal cells may be expected to produce more dissolved oxygen with a greater photon fluence rate, but within limits of the photosynthetic capacity of the system. Describes materials and methods. (LZ)

A procedure for purifying DNA using either bacteria or rat liver is presented. Directions for doing a qualitative DNA assay using diphenylamine and a quantitative DNA assay using spectroscopy are included. (KR)

Described is an interactive video system that reconstructs three-dimensional representations of the brain and its components from two-dimensional serial cross-sections. (KR)

Discusses a microcomputer program that was created to simulate the behavior of a computerized "animal" so that students could practice the shaping of behavior. Describes mathematical algorithms that allowed the "animal" to show gradual improvements in directional movements after appropriate shaping. Reports that students were…

Antagonism is the production of substances by microorganisms that inhibit or prevent the growth of other bacteria. This paper demonstrates the antagonistic behavior of gram-positive coccus on the B. subtilis and Enterococcus faecalis gram-positive microorganisms, showing that the process of antagonism is sometimes dependent on the nutritional…

Describes a microbial bioassay, using molds as test organisms, that demonstrates toxicities of environmental pollutants. Includes laboratory methods and applications for the experiment. (MDH)

Discusses the complexity of chemistry concepts and the identification of instructional barriers in terms of current learning theories. Recommends teaching to improve students' conceptual understanding. Contains 34 references. (WRM)

Examines the thinking processes of 16 eighth grade science writers during laboratory report writing and explores the possibility that writing can contribute directly to science learning. Five students exhibited no mental reflection during writing whereas nine students demonstrated scientific problem solving including hypothesis and evidence…

Presents an activity that involves dropping spherical party balloons onto a sonic motion sensor to show that the force associated with the air resistance is proportional to both the square of the velocity and the cross-sectional area of the balloon. (Author/WRM)

Describes a procedure based on the assumption that during the rated lifetime of a light bulb roughly half of the radius of the filament evaporates. Explains how the filament's operating temperature can be deduced. (DDR)

Presents an authentic semi-guided student research project. Studies the impact of a regional invasion of non-indigenous worm species on decomposition in forest soils. Describes the experimental design, data analysis, and interpretation of the data. (Contains 16 references.) (YDS)