Provides contributed physics activities and laboratory techniques. (CP)

Details construction of an inexpensive electronic auditory device in which the resistance in parallel with the device is inversely proportional to the frequency of sound produced. (CP)

Provides schematics and discussion needed to construct an inexpensive device for classroom demonstrations involving beats and interference. (CP)

Describes a method of measuring the speed of sound that can be done in front of a class on a lab table in 15 minutes, be understood by junior high school students, and be engaging and instructive for students at high school and college levels as well. Provides schematic for sound trigger. (MVL)

Describes an X-Y scanner used to create acoustic holograms. Scanner is computer controlled and can be adapted to digitize pictures. Scanner geometry is discussed. An appendix gives equipment details. The control program in ATOM BASIC and 6502 machine code is available from the authors. (JM)

Described are the purposes, laboratory set-ups, and procedures of four classroom experiments: ultrasound speedometer; vibrating-bar depth gauge; folding three-dimensional model of equipotential surfaces; and a simple optical system for the reconstruction of images from computer-generated holograms. Diagrams and pictures are provided. (YP)

Discusses the effect of silhouetting a vertical vibrating string against a television screen. The article also reports the usefulness of the effect in tuning stringed instruments and as a possible basis for lecture demonstrations and student discussions and investigations. (HM)