Analyzes the motion of a charged point particle started from rest near the center of a charged circular ring. (CCM)

Dynamic field maps and contour curves provide a new way of depicting and analyzing the electric field of uniformly moving point charges. Presents an alternative way of graphically representing the electricity field of a uniformly moving point charge. (CCM)

Tries to clarify and explain some inaccuracies that appeared in a recent article dealing with a current induced in an external circuit due to charges moving within a device, an ionization chamber of planar geometry, in the circuit. (GA)

Investigates the change in weight associated with the electrostatic potential energy for a system of two point charges supported side by side against a weak gravitational field. (Author/GA)

Develops a theory to explain the effect that, when a current passes through a ball bearing, it can act as a motor. The motor can run in either direction on both DC and AC and can be self-starting on DC. Presents some experimental results in support of the theory. (Author/GA)

Describes an alternative set-up for demonstrating Lenz's Law in which the magnet can be seen during its fall. (WRM)

Explores the power transfer using (1) a simple electric circuit consisting of a power source with internal resistance; (2) two different mechanical systems (gravity driven and constant force driven); (3) ecological examples; and (4) a linear motor. (YP)

Discusses three topics related to physics: (1) the center of mass of a long stick thrown horizontally; (2) how electric current flows in metals; and (3) the theory of relativity in relationship with fictionalized time machines. (MDH)

A quantitative application of magnetic braking performed with an air track is described. The experimental measurement of the position of the glider as a function of time is calculated. (KR)

Materials needed and procedures for conducting two activities are provided. The first investigates drops of a liquid which float on water in a watchglass resting on top of a loudspeaker. The second investigates electromagnetic phenomena. (JN)

Reviews three videotapes for physics teachers: (1) "Determination of the Newtonian Constant of Gravitation" showing the Cavendish experiment; (2) "Preview Film for RAM-Tutor Media" introducing a series of seven videocassettes covering physics; and (3) "Determination of the Velocity of Light" using a rotating mirror. (YP)

Discusses: (1) construction of an integrated spherical reflectometer; (2) limitations of the NOAA Weather Radio Network; and (3) a simple experiment to demonstrate/measure influence of damping force on amplitude resonance. Also discusses whether or not a homemade electrophorus can lose its charge and then recharge itself. (JN)

Describes the implementation of a trajectory-plotting program for a microcomputer; shows how it may be used to demonstrate the focusing effect of a simple electrostatic lens. The computer program is listed and diagrams are included that show comparisons of trajectories of negative charges in the vicinity of positive charges. (TW)

Describes a series of laboratory experiments and computer simulations of the motion of electrons in electric and magnetic fields. These experiments, which involve an inexpensive student-built electron gun, study the electron mean free path, magnetic focusing, and other aspects. (Author/HM)

This book is a collection of 66 "How Things Work" columns from the journal "The Physics Teacher," 1983-1991. All the devices and phenomena are ones that are met in everyday life, involve physics principles, and require explanations that are not immediately obvious. Topics include: touch panels in elevators, liquid crystal…