Describes the construction of a small (portable), inexpensive, and easy to build Foucault pendulum. Includes photographs of the apparatus, a schematic of the electrical circuit used, and discussion of the amount of accuracy to be expected during classroom investigation. (JM)

Describes an experiment with resolving ability and how it varies according to the aperture of the telescope used (including the human eye). Although designed for use in college laboratory classes, a method is included that amateur astronomers can use to determine the actual resolving powers of their telescopes. (JN)

Describes an experiment enabling students to apply concept of diffraction, determine limits of their color perception, learn how to measure wavelength with a simple apparatus, observe continuous and line spectra, and associate colors with corresponding wavelengths. The homemade diffraction-grating spectrometer used is easily constructed. (JN)

Describes a low priced ripple tank with accessories for use with an overhead projector as well as the assembly of a variable speed wave source. Photographs are included. (GH)