Discusses the working of a dial lock using a scaled-up model. (JRH)

Describes the concepts behind the working of the Seiko "Kinetic" watch that uses ultracapacitors to store energy. (JRH)

Describes the construction of a new lighting system that uses a sulfur light source no bigger than a golf ball that emits enough light for an entire large room. Discusses the theory behind the system. (JRH)

Explains the physics principles behind the VT (variable time) fuze, also called the proximity fuze, that was used in World War II in a radio device built into the nose of an aircraft shell or bullet that made it explode at the instant of passing an airplane in a near miss. Discusses other uses of the proximity fuze. (JRH)

Introduced is a magnetic compass with no moving parts. Presented are the principles of the compass and the method to make the compass. Shows a lodestone compass which is the most primitive compass form. (YP)

Presents an apparatus, a solid-state sound generator in a plastic ball. Includes pictures of the ball and a diagram of the piezo horn. (YP)

Provides an explanation for the observed motion of frisbees, can lids, "clay pidgeons," and flat stones when these objects are thrown through the air. Explanation focuses on forces (gravity and air), torque, and gyroscopic precession. (JN)

Discusses the making of a light engine powered by sunlight or a lamp. Describes the materials and construction method with detailed specifications and diagrams. (YP)

Discusses the development, workings, and research on piezo motors. Also called ultrasonic motors or vibration motors, piezo motors move by a wave produced by a piezoelectric crystal. (MVL)

Describes the working of an exhibit in the Ann Arbor Hands-On Museum in which separated water drops from two nozzles collide to make interesting shapes. Discusses the calculation of the vibration frequency after the drop breaks away from the nozzle and the effect of drop size and surface tension on this frequency. (JRH)