Experiment of The Month
A Short, Driven, Foucault Pendulum
Our Science Design driven pendulum has been running for three years now. There is also a traditional monumental Foucault pendulum online, the Kirchhoff Institute of the University at Heidelberg
1) The new science building at Millersville has a
2) Dr. Nolan found an article by Richard Crane showing that a short driven Foucault pendulum could be built. The reference is:
A Foucault Pendulum "Wall Clock"
by Richard H. Crane
American Journal of Physics 63, (1) 33-39 (1995).
3)Meron Wollie showed that we can parametrically drive a short pendulum with equipment readily at hand
To see a live image of the swinging pendulum click here. Log in as
At Millersville's latitude of about 40 degrees North, the pendulum should take about 36 hours to
The rate of rotation of the plane of oscillation is not constant, partly because of imperfections in the pivot point. More interestingly, the driving mechanism pulls up on the pivot each time the pendulum passes its low point. The brief upward velocity couples via the Coriolis force to induce a slight elliptical component to the motion. The elliptical path is clockwise
The parametric drive mechanism used here is not the most common method of keeping up the motion of the pendulum. A monumental pendulum using a parametric drive was built in 1988 by Sir Brian Pippard, a physicist noted for his work on the properties of electrons in metals.
Click here for a bookmark with a quick explanation of the Foucault pendulum.
Click here for teaching suggestions for integrating the driven pendulum into an introductory physics course.
Click here for a discussion of the rotation of the plane of oscillation of the pendulum.
Click here for a discussion of how elliptical motion can make the pendulum plane rotate "too fast."
Click here for a large figure, showing 12 photos of one of our pendulums, in various positions throughout a single day.
Click Foucault pendulum at home for some "home-brew" ideas.
Click here for a discussion of the driving mechanism.
For a minute-by-minute record of another kind of real-time earthly motion, check out the MU Earth Science Seismograph page.