Heavily ionizing charged particles produce radiation damage tracks in a wide variety of insulating materials. The experimental properties of these tracks and track recorders are described. The mechanisms by which the tracks are produced are discussed. (Author/KR)

A principle is presented to show that, if the time of passage of light is expressible as a function of discrete variables, one may dispense with the more general method of the calculus of variations. The calculus of variations and the alternative are described. The phenomenon of mirage is discussed. (Author/KR)

Mathematically analyzes the polarization of rainbows, a phenomenon which can be demonstrated in a laboratory simulation using polaroid sheets, perspex discs, and a white light source. (MLH)

Explains magneto-optical effects and describes techniques which may be used, in conjunction with certain materials, to reveal domain structures. In addition, simple experiments are described which enable domains to be observed under various conditions of applied fields. (Author/GA)

Describes a college level exercise in physics for measuring the earth's resistivity. (SL)

A low-cost procedure for metallizing a silicon p-n junction diode by electroless nickel plating is reported. The procedure demonstrates that expensive salts can be excluded without affecting the results. The experimental procedure, measurement, results, and discussion are included. (Author/KR)

Perturbation theory is presented as an invaluable tool for solving a majority of physically interesting problems involving both macroscopic and microscopic objects. Its use in Newtonian mechanics is emphasized.. The method is illustrated with three examples. (KR)

Reports on the international conference on physics education held in Edinburgh, Scotland, July 29 - August 6, 1975. Provides the list of topics discussed by the working groups and notes other activities of the conference. (CP)

Describes how to construct a simple on-axis hologram designed to illustrate the reconstruction of images in terms of Fresnel zone plates and gratings. (GA)

Describes an apparatus for an experiment on winding motion in three dimensions. Discusses theory and provides a calculation example. (JM)

Presents notes on three physics experiments on (1) light and lenses, (2) determination of the pVT surface of a freon, and (3) use of an eyepiece with microscopes and telescopes. (RH)

Describes an open-ended laboratory project suited to science materials. The students are asked to determine the structure, the properties and possible applications of a commercial material that is being developed and supplied by the manufacturer. (GA)

Describes a simple experiment to verify the reflectivity equations of Fresnel and for measurement of optical constants. (SL)