Describes an experiment illustrating a lesson in wave interference using bright colors in a soap film. Illustrations provided. (MA)

Describes the necking of polymer sheets that occurs when they are stretched. Discusses the effect and the mechanisms of necking. Lists four references. (YP)

Describes an experiment that allows the students to verify the assumption that light travels in straight lines. (GS)

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)

Electrets, the electrical counterparts of magnets, are polarized dielectrics that are permanent on a scale of months. Describes procedures for making electrets out of plastic sheets like Mylar, for testing them and measuring their pole strengths, and for establishing necessary and sufficient demonstrations that they are not simply surface charged.…

Describes an experiment in which the free-electron cyclotron resonance of electrons trapped in a microwave cavity by a Penning trap is observed. The experiment constitutes an attractive alternative to one of the Gardner-Purcell variety. (Author/GS)

Described is a simple demonstration that provides a way to determine if a given sample contains even a small fraction of superconducting material. The repulsion of the powder from a magnetic field is indicative of superconductivity. (RH)

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

Describes an experiment in which a recycling oscillator has been designed having a fiber optic data link that closes the loop. Outlines the use of this wink-around system to determine the speed of light and suggests additional application for measuring integrated circuit propagation delays to subnanosecond resolution. (GS)