Finds that first-year college students can understand in detail the origin of the equivalent mass. Provides both a simple calculation derivation of this result as well as a noncalculus derivation. Argues that for every soft spring, the equivalent mass should be somewhere between m0/3 and m0/2. (CCM)

Describes how to build your own drop tower. Notes that these demonstrations are part of a portable and compact demonstration kit that fits entirely into a trunk, television and all. (CCM)

Describes a quantitative approach to the demonstration that the energy of a photon is proportional to its frequency. (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)

Explains a change in sign convention for thermodynamic work. (CCM)

Presents a simple extension of the standard demonstration of the Meissner Effect which shows the superconductor to be a perfect conductor. (CCM)

Finds that quick estimates or mental calculations are usually easier if distances are stated in focal lengths and the equation is written as a function of magnification. (CCM)

Describes how students in an introductory physics and astronomy lab used computer and data interface units to sample a 15 second portion of a prerecorded audiotape of two broadcast stations to measure the speed of light. (CCM)

Outlines a way for instructors to teach astronomy and the nature of scientific inquiry. Highlights a discussion with students during coverage of the Earth-Moon system. (CCM)

Describes an activity that centers around advertisements for alternative medical therapy devises based on magnets. (CCM)

Presents a collection of curious findings from one of the first textbooks studied, a 1958 edition of a fairly popular text. Concludes that the book presents a chance for teachers to enrich their physics classes. (CCM)

Explains some of the properties of refrigerator magnets by conceptualizing their makeup as a line of tiny, consecutive horseshoe magnets. (WRM)

Describes a lesson in which students perform simple body movements in order to gain insight into the relationship between time and the astronomical motions of the earth, and how these motions influence what we see in the sky at various times of the day and year. (WRM)

Describes a contest in which students attempt to build a device that produces a donut-shaped air pulse that will travel the greatest distance with the most accuracy. (WRM)

Explains how a toy called "Sound Bites" can be modified to demonstrate the transmission of sound waves. Students can hear music from the toy when they press it against any bone in their heads or shoulders. (WRM)