Provided are procedures and list of materials needed to demonstrate that the pressure inside a container with a porous surface can be changed due to the rate of diffusion of low molecular weight gases. Typical results obtained are included. (JN)

Briefly considers the nature of physics laboratories and their role in the physics curriculum. Also considers three valuable outcomes of laboratory experiences: using equipment, doing real experiments, and handling phenomena. (JN)

Describes a self-taught optical mineralogy course which uses eleven 40-60 minute color videocassettes. Laboratory exercises, instructional strategies, and development of graphical manipulation and display exercises are considered. Content of each tape is listed. (BC)

Describes a laboratory investigation designed to analyze surface area to volume ratio related to cell division. Uses agar-gel "cells" with pH indicator added which are then "fed" acid for a measured time. Discusses procedures and materials used, providing a sample data table and important guiding questions. (JM)

Measurement of harmonic amplitude and phase response are discussed, focusing on an instrument used to demonstrate motion of a damped system when oscillating freely and motion of the same system when driven into harmonic oscillation. Includes procedures, sample results, and comparison of results to values calculated from geometry of the system. (JM)

Experiments which illustrate the effect of humidity on human hair and on paper are described. Also described are two ways to make a hygrometer. These methods were found in a series of British television programs (also available in the United States). Comments on the programs are included. (JN)

Discusses two activities suitable for group involvement or demonstration purposes. The first focuses on factors which determine how much time an object (such as a ball) will take to fall to the ground from a certain height. The second concerns the nonconservation of volume when two soluble liquids are added together. (JN)

Briefly discusses the theory of fatigue, and describes ways in which the fatigue rate in humans can be measured in the classroom using a simple physiological instrument, the ergometer. (JR)

Describes student activities with mercuric oxide and mercury that help them to form models of the solar system and its creation. (JR)

Describes several experiments, suitable for secondary school biology classes, using the bioluminescent marine bacterium, Achromobacter fischeri. (JR)

Describes demonstrations suitable for secondary school biology classes relating to the effects of the hormone IAA on plant growth. Demonstrations illustrate how hormone treatments affect stem elongation, callus formation, inhibition of axillary buds, stimulation of secondary growth and initiation of adventitious root development, root elongation,…