Details are given for the construction of a 70‐cm‐long Foucault pendulum to be mounted on the wall, and for a simple modification that will make it display local clock time. The possibility of having a Foucault pendulum of such short length is the result of finding new or improved ways of reducing four perturbing effects that become more severe as the length is decreased. They relate to: precession due to ellipticity in the motion, the drive system for maintaining the amplitude, the means of limiting the growth of ellipticity, and the method of gripping the suspending wire at the top. With those improvements, successful Foucault operation was attained in pendulums as short as 15 cm, support to center of bob. Following that severe test, the length for the ‘‘wall clock’’ was set at a conservative 70 cm. At that length it is highly reliable, and accurate to within 2% when timed for the full revolution. Uniformity in rate when comparing different intervals of azimuth is of course less. A simple method of making the pendulum read local time is described. Two clocks, one in the author’s office and one at home, have been in continuous operation for more than ten years.
Skip Nav Destination
Article navigation
January 1995
Papers|
January 01 1995
Foucault pendulum ‘‘wall clock’’
H. Richard Crane
H. Richard Crane
Physics Department, University of Michigan, Ann Arbor, Michigan 48109
Search for other works by this author on:
Am. J. Phys. 63, 33–39 (1995)
Article history
Received:
June 23 1994
Accepted:
June 25 1994
Citation
H. Richard Crane; Foucault pendulum ‘‘wall clock’’. Am. J. Phys. 1 January 1995; 63 (1): 33–39. https://doi.org/10.1119/1.17765
Download citation file:
Pay-Per-View Access
$40.00
Sign In
You could not be signed in. Please check your credentials and make sure you have an active account and try again.
Citing articles via
Ergodic Lagrangian dynamics in a superhero universe
I. L. Tregillis, George R. R. Martin
All objects and some questions
Charles H. Lineweaver, Vihan M. Patel
The most efficient thermodynamic cycle under general engine constraints
Christopher Ong, Shaun Quek
A story with twists and turns: How to control the rotation of the notched stick
Martin Luttmann, Michel Luttmann
The spinorial ball: A macroscopic object of spin-1/2
Samuel Bernard-Bernardet, Emily Dumas, et al.
Related Content
Short Foucault pendulum: A way to eliminate the precession due to ellipticity
American Journal of Physics (November 1981)
The precession of a Foucault pendulum viewed as a beat phenomenon of a conical pendulum subject to a Coriolis force
American Journal of Physics (September 1991)
Hannay angle study of the Foucault pendulum in action‐angle variables
American Journal of Physics (February 1993)
A new model of the Foucault pendulum
American Journal of Physics (April 1979)
The Crane Foucault pendulum: An exercise in action‐angle variable perturbation theory
American Journal of Physics (February 1983)