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)

Describes construction of two flashing light sources: an adjustable-rate battery-powered flasher and a neon tube powered by a 60-hertz electrical outlet. Both devices may be used for a variety of activities, including studies of free-falling object, pendulum period variation, and acceleration due to gravity. (JN)

Electrography is a technique in which unknown metals are identified by the precipitates they form with known electrolytes. The technique illustrates both electrochemistry and precipitation reactions. Describes the technique, suggesting its use in science and forensic science classes. (JN)

Four ways in which microcomputers can be turned into laboratory instruments are discussed. These include adding an analog/digital (A/D) converter on a printed circuit board, adding an external A/D converter using the computer's serial port, attaching transducers to the game paddle ports, or connecting an instrument to the computer. (JN)

Describes an inexpensive device (around $8.00) for measuring light. The circuit used includes five resistors, three small capacitors, a cadmium sulfide light sensor, two integrated circuits, and two light-emitting diodes. The unit is constructed on a small perforated circuit board and powered by a 9-V transistor radio battery. (JN)

Explains strategies for motivating and getting student's attention in science. Presents a laboratory procedure for generating hydrogen using an Erlenmeyer flask and a one-holed stopper apparatus to fill a balloon which is used to produce a dramatic explosion. Safety precautions are cited. (RT)

With an aquarium and a few tools, a simple apparatus to quantitatively illustrate absorption rates of light passing through fresh, salt, and other waters (such as distilled water) can be constructed. Students learn that extinction rates are different and that the intensity/depth relationship is exponential. (DH)

Macrolab (located at New Jersey Institute of Technology) develops devices, training models, and experiments for the scientific education of handicapped students. The construction and operation of a spectrophotometer for blind and visually impaired students are discussed. Construction details are available from authors. (JN)

Describes experiments on diffusion of gases, volumetric approach to water of hydration, and toxicity of chemicals in the laboratory. Also describes an inexpensive automatic pipette, overhead projection of chemical reactions, and an alternative method for demonstrating flame tests. (JN)

Describes procedures for examining a beetle's anatomy with microsurgical tools. Instructions for experimental exercises dealing with the insect's structure and digestive enzymes are outlined. Tips on how to make a microscalpel are also included. (TW)

Water rockets are used to present Newton's three laws of motion to high school physics students. Described is an outdoor activity which uses four students per group. Provides a launch data sheet to record height, angle of elevation, amount of water used, and launch number. (MVL)

Describes the use of a precalibrated stainless steel thermistor, interfaced with an Apple computer, in chemistry experiments. Discusses the advantages of "instant" temperature readings in experiments requiring that readings be taken at certain intervals. Outlines such an experiment which investigates freezing point depressions. (TW)

Presents two models and two demonstrations targeted at student understanding of projectile motion as the sum of two independent, perpendicular vectors. Describes materials required, construction, and procedures used. Includes a discussion of teaching points appropriate to each demonstration or model. (JM)