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)

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)