Describes the construction and use of an inexpensive, homemade polarimeter which can analyze optically active compounds. Ideas for activities using the apparatus are suggested. (JN)

A homemade device for testing particle scattering is described. Also described are experiments in zero gravity conducted in free fall in the cargo space of an airplane belonging to the National Aeronautics and Space Administration. (JN)

Describes a way to construct from aluminum foil and a tin can a detector of ionizing radiation in the environment. (Author/SA)

Describes an inexpensive apparatus for the detection of gravity waves traveling through the ionosphere. The detector consists of a modified transistor radio with a ferrite-core antenna. Numerous diagrams accompany a lengthy description. (CS)

Presents the plans for constructing a spectrophotometer which can scan the spectrum in a thirtieth of a second. The instrument can be used to determine the absorption characteristics of a solution compared to a pure solvent. The instrument allows time to investigate phenomena that occur quickly. (Author/SA)

Described is a way for an amateur to build a mercury-vapor ion laser which was devised by Dean Morelli. Morelli's laser emits bright pulses of green light and dimmer pulses of red-orange light and is the first gaseous-ion laser. (Author/DS)

Describes a simple seismograph which can be built quite easily and is sufficiently sensitive to record earthquake waves at home. (HM)

Discusses advantages of the Stirling engine. Describes the details of constructing one from common materials, and its use for studying thermodynamics. (YP)

A thermal oscillator is a self-sustained, nonlinear oscillating system. One part of the system vibrates continuously because of the transfer of heat. Four such devices, two new and two demonstrated in the 19th century are described. Although each depends on the periodic redistribution of heat, they are all quite different. (Author/JN)

Describes a method to detect the presence of microgram quantities of nearly any metal in samples of alloys, minerals, water, and air. This chemical-spot testing technique requires no elaborate equipment and can be done by an amateur. (SK)