Discusses two procedures for the identification of nitrate, the standard test ("Brown Ring" test) and a new procedure using triphenylbenzylphosphonium chloride (TPBPC). Effectiveness of both procedures is compared, with the TPBPC test proving to be more sensitive and accurate. (JM)

Presents a novel approach to identification of unknown alcohols using experimental measurements of boiling point and viscosity which are easily obtained without expensive equipment of instrumentation. Provides instructions for preparing capillary viscometer, listing special hints for obtaining good results. (JM)

Presents a series of experiments built around the bacteria found in the intestinal tract of formalinized rats as a model for discussing microbial ecology. Describes methods of examination of intestinal content, student tasks, and discussion questions; also gives a challenge problem to solve.

Describes a recently discovered and translated work by Archimedes in which he constructed a balance to determine the amount of gold in an alloy of gold and silver. A description of the balance (translated verbatim) as found in Archimedes' work "On Balances" is included. (JN)

Objectives, materials needed, procedures, discussion questions, and follow-up activities are provided for five experiments. They include (1) testing for sugars; (2) comparing sugar to artificial sweeteners; (3) chewing gum scientifically; (4) soap making; and (5) making toothpaste. (JN)

Recommends an experiment which will help students experience the physical evidence that floors, tables, and walls actually bend when pressure is exerted against them. Set-up includes: laser, radio, solar cell, and wall-mounted mirror. When the beam is moved by pressure on the wall, participants can "hear the wall bend." (DH)

Peroxides are unstable, shock-, thermal-, and friction-sensitive compounds whose sensitivity increases with concentration. In addition, peroxides can form in aging organic solvents and stored alkali metals. Cautions related to storage, use, and disposal of peroxides in the secondary school chemistry laboratory are discussed. (JN)

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)

A laboratory experiment that involves solving problems with conflicting evidence or inconsistent data. The experiment gives students opportunities to reason as scientists. (EB)