Applies the narrow-band model to the instruction of intrinsic and extrinsic semiconductors along with the phenomenon of compensation. Advocates the model for undergraduate instruction due to its intuitive appeal and mathematical simplicity. (CP)

Explains the necessity for a domain concept in understanding ferromagnetism and discusses various factors influencing the domain configuration in a crystal. (MLH)

Describes a simple experiment to verify the reflectivity equations of Fresnel and for measurement of optical constants. (SL)

Continues a discussion of magnetic fluids by providing background information on and procedures for conducting several demonstrations. Indicates that, with a little patience and ingenuity, only modest magnetic fields and about 20 ml of low-viscosity, commercial magnetite-water-based magnetic fluid are required. (JN)

Basic physical concepts of importance in understanding magnetic fluids (fine ferromagnetic particles suspended in a liquid) are discussed. They include home-made magnetic fluids, stable magnetic fluids, and particle surfactants. (DH)

Suggests using musical instruments to demonstrate physics concepts. Topics include: pitch and frequency; string vibrations; string-resonator system; wind instruments; harmonic content; transients; scales and temperament; psycho-acoustical affects; and electronic music. (SK)