Describes the computer generation of random and regular arrays of apertures on photographic film and their applications for classroom demonstrations of the Fraunhofer patterns produced by simple and complex apertures, Babinet's principle, resolution according to the Rayleigh criterion, and many other aspects of diffraction. (LC)

Described is a simulator that illustrates the different operations of a mass spectrometer. (CS)

Procedures for constructing an inexpensive, illuminated, monocular, low-powered microscope are presented. Materials include a commercial lens and a specially designed plastic moulded stand which incorporates a bulb holder and opaque plastic stage. (Author/DC)

Describes a milk bubble machine to be used to demonstrate the acceleration of gravity in the classroom. Instructions are given for the construction of the milk-bubble-acceleration-of-gravity machine. (Author/DS)

Describes refinements and modifications in the construction of an apparatus to study the kinetics of fast reactions. (CS)

Describes an undergraduate laboratory project that combines microprocessor programing, interfacing, and system design to produce an inexpensive multichannel analyzer. (Author/CS)

Deals with the conversion of electronic hand calculators to timing devices. This article illustrates a conversion of a rather versatile calculator by means of simple and inexpensive circuitry. (HM)

Describes a "flat" linear air track, glider and spark timer system for use in the physics laboratory. The results of experimental tests using the system are briefly stated. (SA)

Describes and evaluates the Tel-X-Ometer, its performance, and its accessories. The apparatus, with its low intensity x-ray beam, is specifically designed to make x-ray experiments safe, practical, and affordable for the students. (GA)

Presents an activity that encourages students to think as scientists and explores microgravity. Employs a drop tower built with simple materials. (DDR)

Presents a variety of activities that support the development of an understanding of Newton's laws of motion. Activities use toy cars, mobile roads, and a seat-of-nails. Includes a scoring rubric. (DDR)