This experiment develops the students' ability to carry out a simple recrystallization effectively, and demonstrates how a solvent may be selected or rejected for the recrystallization of a specific organic compound. (Author/BB)

The setup described here for recording chemical transient phenomena is intended to be simple and an instructive example of interfacing experiments that can be performed on any microcomputer possessing adequate memory and input-output facilities. (BB)

Reports on an experiment that measured passage-dependency in an ESL test. Results suggest that passage-dependency is one measure that can be used to select good reading comprehension tests. (Author/AM)

Provides five secondary level investigations designed to examine allelopathy, the inhibition of plant growth by chemicals produced by another plant. (MA)

Describes the experiment and the apparatus used to measure electrostatic forces between charged parallel plates and points out possible pitfalls in constructing the apparatus. (GA)

A practical exercise is described that allows students to investigate a specific problem using a variety of biochemical techniques. The need for a thorough understanding of the theoretical principles underlying these processes is emphasized. A program of private study and assessment is suggested to enable the progress of students to be followed.…

A new scale is suggested, with the objective of simplifying relationships between the various scales and units used in spectroscopy. Although there are certain drawbacks to such a scale, it is hoped that the suggestion will stimulate discussion on the relevance of the many scales and units that are used. (Author/BB)

Discusses some high school physics demonstrations and experiments on a variety of topics: such as uses of the dipole, the vapour-liquid critical point, velocity of sound in metallic rods, the flux-density near a bar magnet, and a different style logic gate using basic units. (GA)

Surveys new laser techniques and a variety of spectroscopic experiments that can be used to detect, measure and study very small numbers of atoms on molecules. The range of applicability of these techniques is also included. (HM)

Describes several experimental results selected from typical inorganic and organic reaction systems, along with a brief description of the physical parameters needed to determine if a pressure increase will help solve a synthetic problem. (HM)

Describes a college student chemistry laboratory experiment that illustrates the construction of a polarimeter from inexpensive, readily-available materials. (HM)

Lists several ideas for experiments for the amateur scientist to try or design. The list covers a wide range of topics; sound, mechanics, thermodynamics, fluids, optics, and electrostatics. (GA)

Gives a perturbation analysis to recurrence effects of the spring pendulum. The recurrence depends on two conservation laws which determine the motion in an intermediate region; oscillations outside this region are unstable and must return. Gives the relation to Fermi-Pasta-Ulam problem together with the explicit solution. (Author/GA)

Describes an inexpensive double-beam laser photometry experiment to determine the molar heat of sublimation of I-2. The experiment employs common laboratory materials and components and gives results with a two percent to three percent accuracy. (Author/GA)

Gives an outline description of electronic circuitry which is analogous to the optical diffraction grating or to crystals used in the Bragg reflection of X-rays or electron waves, and explains how to use it. (Author/GA)