Describes a photogate electronic flash trigger that synchronizes flash discharge with high-speed events. Presents a photographic study of a high-speed collision demonstrating the passage of a BB through an elastic strip. Provides the schematic of the delay circuit utilized in the trigger. (MDH)

Uses diagrams and text to illustrate the use of Lissajous figures (the figures that are traced out when two simple harmonic motions are combined at right angles to each other) in teaching basic physics concepts. Covers the mathematics of the Lissajous Figure; demonstrating Lissajous Figures; and a typical class. (ZWH)

Describes a community-college curriculum that incorporates Socratic Dialogue Inducing (SDI) laboratories into a new calculus-based preengineering physics sequence. SDI allows for group discussion labs that emphasize the concepts being taught in the lectures. (ZWH)

Presents a laboratory exercise to reinforce the concepts of conductivity and resistance. Students measure resistance over rolled out Play-Doh of differing lengths and widths using the four-point resistance measurement method. (MDH)

Describes a safe but qualitative alternative to an experiment in which bullets are shot into wooden blocks from below, with some bullets hitting the blocks in the center and others off-center. Explains why the off-center blocks reach greater heights in spite of the fact that the bullet's energy is divided between translational and rotational…

Discusses the merits of the Spectrum Techniques gamma spectroscopy system as used by university students to determine the mass-energy of an electron from measurements of the energies of Compton-scattered gammas. (WRM)

Describes the use of potassium chloride in quantitative project investigations into radioactivity. (WRM)

According to historical stories, the Saxons placed a bowl with a hole in its bottom in water and used the time it took the bowl to submerge to limit orations. Describes a science activity in which students find a relationship between the diameter of the hole and the time to submergence. (WRM)

Summarizes the results of a 1969 experiment survey made for learning the impact of special publications and the trend of experimentation in colleges. Describes some new or modified apparatus that has appared since the 1956 survey. (GS)

Describes construction of an inexpensive wind tunnel and a water manometer; experiments with model airplanes; and the calibration of the manometer and its use to measure wind velocity and lift on an airplane wing. Additional experiments with an electric fan are suggested. Diagrams are included. (GH)

A capacitor is discharged to generate an acoustical pulse and start a digital counter which is stopped by a microphone. Differences are accurately measured by positioning the sensing microphone on an optical bench. Results are discussed and extended experiments are suggested. The sources of some components are given. (GH)

Describes three simple experiments using Fermat's principle; a single reflection, Schwarz's triangle problem, and light triangle inscribed inside a circle. (GA)

A simple device used to demonstrate the main features of primary color addition is described. Materials needed to construct the device, procedures used, and typical results are discussed. (JN)

Described is a technique for utilizing television video equipment to display diffraction and interference phenomena for elementary physics courses. (SL)