Articles describing construction of an inexpensive spectrograph, improving focusing of Polaroid cameras, use of space satellites for instruction, and construction of an optics demonstration platform. (RH)

Describes the following: a low-pressure sodium light source; a design of hot cathodes for plasma and electron physics experiments; a demonstration cart for a physics of sound course; Bernoulli force using coffee cups; a spark recording for the linear air track; and a demonstration of the effect of altering the cavity resonance of a violin. (GA)

Describes three pieces of scientific apparatus and their demonstrational use: a high temperature apparatus for positron annihilation studies, a digitally synthesized classroom variable star, and a demonstration of plasma laser-beam focusing using paint stripper flames. (GA)

This collection of notes describes (1) an optoelectronic apparatus for classroom demonstrations of mechanical laws, (2) a more efficient method for demonstrated nuclear chain reactions using electrically energized "traps" and ping-pong balls, and (3) an inexpensive demonstration for qualitative analysis of temperature-dependent resistance. (CS)

Describes the following: an electric circuit for an expensive photometer, an amplifier circuit capable of demonstrating many aspects of behavior of free and driven oscillators, and finally a projection recording system which uses an unmodified XY or XT recorder and a separate overhead projector. (GA)

Describes an intelligent lightbulb, an optelectric feedback circuit which bridges the conceptual gap between manual and all-electric servos. The circuit is simple and easily understood in dc terms. Also describes a device for demonstrating wave motion constructed with plastic soda straws. (Author/SK)