Invented by French scientist Léon Foucault in 1851, the pendulum consists of a polished ball weighing 200 pounds swinging from a three-story cable over a compass rose on the floor beneath it. As the Earth rotates, it appears the plane of the pendulum swing is moving. But it’s not; it’s the Earth beneath it that is moving.
“More than just a decoration, a Foucault pendulum is actually a scientific instrument,” FLC spokesman Mitch Davis said. “The Geosciences, Physics and Engineering Hall will be home to an array of scientific equipment to help study the Earth and beyond, including the Foucault pendulum, an invention that continues to inspire and educate since the mid-1800s.”
The pendulums show different results based on where they are located in the world, Davis said. A pendulum at the North Pole makes one clockwise rotation per day. A pendulum at the South Pole also makes one rotation each day but it’s counterclockwise. The plane of a pendulum suspended at the equator is fixed relative to Earth.
The pendulum, which hangs in the northeast corner of the hall, is the gift of Grace Deltscheff, on behalf of herself and her late husband, Gustav Deltscheff. It was created by Academy Pendulum Sales in California, which specializes in Foucault pendulums.
The hall is scheduled to be completed in November, and while professors will begin moving in equipment, extensive rock and fossil collections and their offices at that time, the building will not open for classes until the second semester begins in January.
“We’re planning the grand opening for April when the weather’s nicer,” Davis said. “We’d like to do some stargazing stuff and don’t want people to freeze.”