Theories associated with the gravitational collapse of a star into black holes" are described. Suggests that the collapse and compression might go through the stages from white dwarf star to neutron core to black hole." (TS)

Einstein's equivalence principle relates effects seen by an accelerating observer to those experienced by an observer in a gravitational field, providing an explanation of bending of a light beam by gravity. Because the calculations lead to results one-half the value found experimentally, obtaining the correct light deflection is discussed.…

Presents an exercise that examines the lever systems that function in the chelae of the American lobster. Involves calculating the mechanical and distance advantages of the crusher and pincer chelae and estimating the actual forces generated by the contraction of the muscles and the magnitude of the forces transmitted around the fulcrum to the tip…

Presents activities that use a simple homemade apparatus called "the cannon" to demonstrate Newton's Third Law. Reviews the chemistry concepts behind the ignition of the cannon and presents the Momentum Lab and the Projectile Motion Lab. (JRH)

Presents an activity designed for introductory physics courses that enhances students' understanding of the concept of waves, especially the superposition of waves. Uses two different approaches that end with the same result and enable students to see the connection between spatial and temporal properties of waves and their superposition. (JRH)

Presents a brief life history of Maria Goeppert Mayer who won the Nobel Prize in Physics in 1963 for her work in atomic physics. (JRH)

Describes the behavior of a pulse during inversion of the pulse in a string when it reflects from a fixed end. Discusses the forces it exerts on the fixed end. (JRH)

Describes a method to eliminate the nonlinearity from a spring that is used in experimental verification of Hooke's Law where students are asked to determine the force constant and the linear equation that describes the extension of the spring as a function of the mass placed on it. (JRH)

Presents experiments that use a video cassette recorder (VCR) to demonstrate polarization of radio waves using two dipole antennas and a spark gap transmitter tuned to a frequency of either 60-66 MHz or 66-72 MHz with wavelengths of 5 or 4.3 meters, close to the wavelengths of the original work done by Heinrich Hertz. (JRH)

Examines the everywhere-observable phenomena of waveforms, and how waves transport energy across a distance within some given medium. Discusses how waves are described, what happens when waves meet, the specifics of standing waves and echoes, and an introduction to Fourier analysis. (JJK)

Defines the vibrations of a tuning fork against a computer monitor screen as a pattern that can illustrate or explain physical concepts like wave vibrations, wave forms, and phase differences. Presents background information and demonstrates the experiment. (Author/YDS)

Describes an experiment in an algebra-based introductory physics course to determine the power expenditure formulation for a person walking on a treadmill. (YDS)

Introduces an activity concerning air pressure. Using an egg and a heated bottle, the air inside the bottle draws the egg into the bottle. (YDS)

An atlatl is a thrower for propelling a flexible dart through the air. Describes a class investigation for making an atlatl using a piece of dowel. (Author/MM)