Describes a simple, inexpensive system that allows students to have hands-on contact with simple experiments involving forces generated by induced currents. Discusses the use of a dynamic force sensor in making quantitative measurements of the forces generated. (JRH)

Describes the construction of a new lighting system that uses a sulfur light source no bigger than a golf ball that emits enough light for an entire large room. Discusses the theory behind the system. (JRH)

Presents a derivation of Kepler's Third Law for elliptical orbits that requires students to have a knowledge of angular momentum and conservation of energy. (JRH)

Discusses the theory behind a study of motion where a hollow plastic sphere racing against a steel sphere in two parallel sections of inclined channeling always reaches the bottom first; once on the floor, however, the steel sphere travels faster, speeding past the plastic sphere when both are about one meter from the base of the track. (JRH)

Presents experiments that use Microcomputer Based Laboratory (MBL) techniques to enable freshmen physics students to investigate complex systems, such as nonlinear oscillators or coupled harmonic oscillators, at a level appropriate for an independent project. (JRH)

Discusses the theory behind the changes in the times of sunrise and sunset and the sun's apparent gradual week-to-week motion. (JRH)

Presents a simple activity to determine the layout of the magnetic poles in a flat rubber or plastic refrigerator magnet. (JRH)

Discusses the events in the ninth century that moved astronomy away from the pursuit of mystical hermetic sciences and astrology back toward observation and measurement. Describes the achievements of astronomers and the instruments and calculations used during that period. (JRH)

Presents the theory behind the spots of light observed inside a balloon when it is exposed to light. Discusses the use of this phenomenon in teaching optics lessons. (JRH)

Presents the temperature profile of the Duracell Test Strip obtained using a Inframetrics 740 thermal imaging radiometer and ThermaGRAM95 software and compares this to the theoretical profile derived by Clark and Bonicamp. (JRH)

Presents a method to measure the mass of a definite amount of a gas that occupies a known volume at a given pressure in order to determine experimentally the root mean square speed of molecules of a gas. (JRH)

Presents a demonstration of kinematics principles that stresses conceptual analysis over equation manipulation. Aims at focusing students' attention on concepts by using comparative problems, allowing students to predict the outcome of the demonstration and explain the reasoning behind their predictions, and extending the context in which the…

Presents a simple variation on multiple-choice testing that overcomes some of its drawbacks but still permits easy hand or machine grading. Gives student partial credit for partial knowledge and reduces frustration because students are no longer forced to choose between answers that they think might be correct. (JRH)

Discusses the discovery of radioactivity by Henri Becquerel in 1896. Describes his experiments and communications. (JRH)

Uses Newton's laws of motion to describe the theory behind the observation that when bread falls off a table it always lands butter-side down. (JRH)