Discusses the change in pressure as a balloon expands. Describes the pressure change in a spherical soap bubble and a rubber membrane on the tube. Provides demonstrations when two balloons are connected by a tube. Lists five further reading materials. (YP)

Presents a procedure by which cytokinins are used to induce a population of dividing and differentiating cells on the cut surface of the roots of an intact plant. Includes the method used, results, and suggestions for a variety of variables that may be tested. (RT)

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 the construction and use of an osmometer that is low in cost, easy to make, and durable. Materials needed and procedures are outlined. Diagrams show an assembled instrument and individual parts. (RT)

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)

Explains the problem of analyzing a phase object, separating the contribution due to thickness variations and that due to refractive index variations. Discusses the design of an interferometer and some applications. Provides diagrams and pictures of holographic images. (YP)

Presents arguments against lab dissection in the science classroom. Author discusses adult negative memories associated with earlier school dissections. Asserts that, for the early adolescent, dissection may be mingled with messages pertaining to sex, excretion, identity, and privacy. Suggests that dissection arouses a feeling of "defilement": a…

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)

Uses a Vygotskian framework to examine students' (n=26) use of tools in a ninth-grade physical science classroom during a unit on electric circuits. Indicates that conceptual progress may be hindered by students' need to first understand the tools in terms of everyday application. Advocates selection of laboratory tools and activities that match…

Shares background information on the National Vocational Qualification (NVQ) and Scottish Vocational Qualification (SVQ) assessment systems which were developed from the United Kingdom's national standards for laboratory technicians working in schools and colleges. Offers recommendations for individuals or institutions that are preparing to…

Relays one school science technician's experiences in taking a course designed to improve and standardize technician credentials in the United Kingdom. (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)

The work done in a chemistry laboratory is compared to cooking, as both processes use books for reference. It is felt that cooking and chemistry are complex processes and are creative endeavors that require skills beyond those developed by merely following the directions.

Molecular biological methods, such as the polymerase chain reaction (PCR) and gel electrophoresis, are now commonly taught to students in introductory biology courses at the college and even high school levels. This often includes hands-on experience with one or more molecular techniques as part of a general biology laboratory. To assure that most…

An introductory undergraduate physical organic chemistry exercise that introduces the harmonic oscillator's use in vibrational spectroscopy is developed. The analysis and modeling exercise begins with the students calculating the stretching modes of common organic molecules with the help of the quantum mechanical harmonic oscillator (QMHO) model.