Describes (1) a tri-color light-emitting diode (LED) and (2) modification of a demonstration using a dollar bill held between two soft drink bottles, one inverted upon another mouth-to-mouth. The modification consists of filling the bottles with water to increase their mass. (JN)

Presents three ideas to help hold costs down in purchasing and using science equipment. These include (1) use of pencils and other graphite rods as sensors in potentiometric titrations, (2) rubber bulb modification for pipetting, and (3) a heater for a glassware bath. (JM)

Describes a modular approach to help select the most effective instruments for particular applications. In the approach, an instrument is considered to be a system composed of modules, each module performing a particular function. General input/output functions of various modules, how they modify signals, and module sensitivity are discussed. (JM)

Describes (1) use of VELA (a stand-alone programmable instrument); (2) forced harmonic motion of galvanometers; (3) holographic interferometry and measurement of small angular displacement; and (4) an analogy useful on teaching capacitors at A-level. Also describes a comparison of fuses and circuit breakers using a microcomputer as a storage…

Describes an undergraduate experiment for the potentiometric determination of urea based on the physical entrapment of urease on the tip of an ammonia gas sensor. An advantage of this technique is the ease with which the ammonia electrode can be converted to a urea electrode. (JN)

Presents a list of books, test kits, and audiovisual material available for studies of the environment and provides prices and opinions on each. (GS)

Discusses the theory of radiometric force and the historical development of the radiometer. (MLH)

Discusses the teaching potentialities of scaler-timers in the physics laboratory, and describes the circuitry and design of scaler-timers. (MLH)

Describes the construction of simple microwave sources of centimeter wavelength with bulk-effect diodes, and accessory equipment for experiments and demonstrations in physical optics. (MLH)

Describes a low-cost wave analyzer; how to convert an incandescant light bulb to an x-ray tube; how to use an electric toothbrush to generate waves; the use of a light-emitting diode as a point light source; how to rejuvenate helium-neon lasers; and calibration of an ammeter. (MLH)

Describes the use of the magnetometer in an introductory undergraduate geology course. (SL)

Described is the construction and utilization of a Dewar assembly for measuring the heat of vaporization of liquid nitrogen. The device is fabricated from a thermos bottle replacement filler. (SL)

Described and evaluated is a new wave form analyzer and an electrolysis apparatus. (SL)

Describes the construction and application of two new types of detectors that use the discharge provoked in a gas by the passage of a charged particle as the means of detection. (MLH)

Includes five brief articles on: solar-heating demonstration equipment, mercury or sodium vapor lamp spectroscopy, an apparatus for simulating variable stars, a voltage-to-frequency converter, and an introductory absorption experiment for low-energy beta particles. (MLH)