Samford University

Hidden Gems: Samford's Pendulum Swings

By Jimmy Lichtenwalter

Descending to the bottom floor of Samford University's William Self Propst Hall, it is hard to miss the pendulum swinging by the stairwell. Even harder to miss is the large, enclosed compass etched into the basement over which the pendulum swings. The compass depicts the official university seal and the motto in Latin: Deo, Doctrinae, Aeternitati. (for God, for learning, forever).

PendulumThis particular kind of pendulum, called a Foucault pendulum, is no mere decoration. It was installed in 2001 when the building first opened. Despite its elegance, it actually serves as a constant reminder that the Earth is rotating.

Created by and named after French physicist Léon Foucault, this pendulum was designed as an experiment to prove that Earth is rotating. It debuted at the 1851 World's Fair in Paris. While the idea of Earth's rotation was nothing new, Foucault's experiment was the first to simply demonstrate visual proof of the planet's rotation.

When a fixed pendulum is left free to swing, it appears to travel around compass it is swinging over. Yet, this is an illusion. The pendulum actually is swinging along the same plane. As the Earth and the compass below the pendulum rotate, it only appears that pendulum's swing has shifted planes as the day progresses.

To determine how many degrees a Foucault pendulum will shift in 24 hours (N) the equation N = sine of latitude x 360 is used. According to that equation, the Foucault pendulum in Propst Hall travels about 198 degrees within 24 hours, according to university officials.


Jimmy Lichtenwalter is a news and feature writer in Samford's Office of Marketing and Communication and a sophomore journalism and mass communication major.

[Editor's Note: This article is one in a recurring series on "hidden gems" on the Samford University campus.]