Information about the Hadley Pendulum

The Hadley Pendulum is a Foucault Pendulum named in honor of Professor Emeritus Lawrence Hadley, who originally joined the CSU (then Colorado Agricultural and Mechanical College) Physics faculty in 1947, departed for a few years, and then returned in 1955 and has remained a CSU faculty member ever since. He served as Chairman of the department from 1965 to 1968.

What is a Foucault Pendulum? It is really just a pendulum, that is to say, a heavy "bob" swinging on a cable suspended from a fixed point above, but which swings for a sufficiently long time that one can observe the effects of the Earth's rotation on the motion of the bob. If the Earth did not rotate, then the motion of the bob should lie in a fixed (vertical) plane; but since the Earth does rotate, anywhere on the surface of the Earth (except along the equator) the plane of motion also rotates. A fairly detailed "cartoon physics" discussion of the Foucault Pendulum is presented by the California Academy of Sciences.

This particular pendulum has a period of about 5 seconds. The mass of the polished steel bob is about 270 pounds. In order to keep the pendulum swinging, there is an actively controlled electromagnetic drive located near the top of the cable. The observed precession rate of the pendulum is very close to the theoretical value of 9.76 degrees/hour.

Credits for design, construction, and installation of the Hadley Pendulum go to Dave Warner, Jay Jablonski, and Bob Adame.