Describes an experiment which makes use of a number of concepts from geometrical optics. The apparatus and method which is intended for students in elementary college physics classes are included. (HM)

This article focuses on discoveries in astronomy during the past 20 years using a wide range of observing techniques. The future is seen as a time when astronomers will learn more about the distribution of mass in the universe, the physics of energetic sources, and the intricate interconnections of astrophysical processes. (Author/SA)

Describes a modification in the use of artificial substrates to study attached micro-algae. Apparatus is based on glass microscope slides immersed in natural water environments; biomass and primary productivity are assessed by measurement of alpha-chlorophyll. Describes use in studies of colonization, succession, and populational fluctuation. (CS)

Provides illustrated directions for the construction and use of a low-cost thermistor device. Attached to a servo-type millivolt chart recorder, the device will record minute temperature changes and will simulate data obtained from an oxygen polarograph. Includes results of experiments with baker's yeast. (Author/CS)

Lists and describes a variety of major national astronomy organizations which amateurs can join. It also lists stores and institutions across the U.S. that offer a discount to members of the Astronomical Society of the Pacific (ASP). (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)

Described is a method for bringing the sea into the classroom by setting up a saltwater aquarium. Included is selection of an aquarium, filtering systems, water (whether natural salt or synthetic sea salts), bottom materials, setting up an aquarium, system stabilization, stocking an aquarium, and maintenance of the aquarium. (DS)

Describes the photodiode array and the electrical connections necessary for it. Also shows a few of the optical demonstration possibilities-shadowgraphs for measuring small objects, interference and diffraction effects, angular resolution of an optical system, and a simple spectrometer. (Author/DS)

Described is an apparatus for determining the Curie temperature of a Ferromagnetic material which enables large specimens to be heated up to a maximum of 1100K in 20 minutes. Included is the theory, magnetic circuit apparatus, electrical circuit, and results using this apparatus. (DS)

Describes details of the construction of a simple compact schlieren experimental setup as an instructional aid. This new optical method is easy to apply, noninterfering, nondestructive, free from inertia, and can produce instantaneous records of transient phenomena, and is comparatively inexpensive. (Author/SK)

Describes an apparatus that uses a microcomputer as a timing device in which the Coefficient of Restitution (COR) is measured. Diagrams of a circuit for timing measurements and a flow chart of a program that measures COR are provided. A list of COR for some common objects is also included. (CS)

Presents the construction, operation, and theory of a Sargent-Welch scattering apparatus. Procedures for using the apparatus are also presented for high school teachers. (HM)

Presents details of anodic stripping analysis (ASV) in college chemistry laboratory experiments. Provides block diagrams of the analyzer system, circuitry and power supplies of the automated stripping analyzer, and instructions for implementing microcomputer control of the ASV. (CS)

Describes the process of collecting and maintaining a culture of protozoa. Instructions are also given for constructing a micropipette for transfering small organisms. (SA)

Investigates the "photographic" appearance of a cube moving at relativistic speeds, and shows that it depends upon whether the camera is held fixed with the optic axis perpendicular to the direction of motion or panned to follow the cube as it moves. (Author/GA)