Describes a laboratory activity which can be done with equipment normally available for introductory college courses. It measures the ratio of the radioactivity per unit mass of a unicellular alga to the radioactivity per unit mass of the medium in which it grows. (HM)

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

Presents an experiment on the bending of light in a medium with a continuously varying index of refraction. Several theoretical approaches for the analysis of this experiment, designed for college physics students, are also presented. (HM)

Describes an advanced undergraduate physics experiment which permits the measurement of ultrasound velocity and absorption in liquid systems. A description of the tasks the student is expected to perform is also included. (HM)

Discusses a demonstration in which the near and far focusing distances of a student volunteer are measured and his or her glasses prescription is computed. (HM)

Describes a demonstration in which the local inertial frame of reference can be obtained in the laboratory by allowing a cage to fall freely without rotation under the influence of gravity. (HM)

Describes a laboratory scale reactor that determines the kinetics of a gas-solid catalytic reaction. The external recycle reactor construction is detailed with accompanying diagrams. Experimental details, application of the reactor to CO oxidation kinetics, interphase gradients, and intraphase gradients are discussed. (CS)

Describes an air track experiment which involves a massive particle incident on a fixed wall with a light particle trapped in between. An analysis for this experiment, which is intended for junior and senior college students, is also included. (HM)

Presents four notes that report new equipment and techniques of interest to physics teachers. These notes deal with collosions of atoms in solids, determining the viscosity of a liquid, measuring the speed of sound and demonstrating Doppler effect. (HM)

Provides procedures appropriate for a high school chemistry class that demonstrate the Arrhenius law by determining the heat of vaporization of a volatile liquid. (CS)

Described are the components for a high-fidelity sound-reproducing system which focuses on various program sources, the amplifier, and loudspeakers. Discussed in detail are amplifier power and distortion, air suspension, loudspeaker baffles and enclosures, bass-reflex enclosure, drone cones, rear horn and acoustic labyrinth enclosures, horn…

Describes a simple hydraulic analog which allows students to explore some physical aspects of the cardiovascular system and provides them with a means to visualize and conceptualize these basic principles. Simulates the behavior of arterial pressure in response to changes in heart rate, stroke volume, arterial compliance, and peripheral…

Two implanted slide techniques are described by which activity of proteolylic bacteria and the growth of algae in the soil can be readily studied by school students using simple apparatus and methods. Variations are suggested for studying the effects of agricultural practices and environmental conditions on the soil bacteria and algae. (Author/DS)

Presents recommendations sent to schools by the Laboratory Safeguards Sub-Committee in the United Kingdom to prevent hazards of a number of chemicals. How to avoid phosphorous fires and accidents from doing dangerous experiments in chemistry are also included. (HM)

Discusses the Weinberg-Salam theory of the weak and electromagnetic interactions which is an attempt at a partially unified theory for physics. (HM)