In the museum wing of the Greenslade house is a clock with a two-second pendulum about one meter long. This ticks once per second, and every time it passes through dead center it completes an electrical circuit. When I came to Kenyon in 1964, this system was used to send signals to a series of telegraph relays, which ticked once per second.…

In a familiar demonstration, a hoop and a solid disk of the same diameter and mass are started from rest at the top of an inclined plane and race to the bottom. The disk reaches the bottom with a larger speed than the hoop and arrives first. Why?

Lissajous figures, and other harmonic curves, straddle the line between physics and art. The sight of a harmonograph tracing out its curves in the Amherst College physics library in 1957 was certainly one of the things that drew young Tom Greenslade into physics and inspired a career-long appreciation of them.

Physics students often have problems understanding waves. Over the years numerous mechanical devices have been devised to show the propagation of both transverse and longitudinal waves (Ref. 1). In this article an updated version of an early-20th-century transverse wave machine is discussed. The original, Fig. 1, is at Creighton University in…

Barlow's wheel has been a favorite demonstration since its invention by Peter Barlow (1776-1862) in 1822. In the form shown in Fig. 1, it represents the first electric motor. The interaction between the electric current passing from the axle of the wheel to the rim and the magnetic field produced by the U-magnet produces a torque that turns…

One of the rewards of walking up the scores of steps winding around the inside of the shaft of a lighthouse is turning inward and examining the glass optical system. This arrangement of prisms, lenses, and reflectors is used to project the light from a relatively small source in a beam that can be seen far at sea.

Describes experiments which could be performed on an 1860 rotating table apparatus. (CP)

Discusses physics of bicycles, presenting a model of the forces acting on the bicycle and its rider. Topics considered include maximum speed coasting down a hill, maximum speed on the level, and maximum speed up a hill. This material is suitable for homework problems, independent study, or regular class work. (JN)

Describes the construction and use of a set of "relativistic metersticks" that represent the apparent lengths of a meterstick passing a stationary observer at relative speed v/c. (WRM)