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Visitors to the Albertus Magnus Science Hall on the California campus of 91����� Aquinas College will see a large brass sphere, dangling some 25 feet from the ceiling in the building�s lobby. On the floor beneath stands a circle of pegs, which the swinging sphere steadily knocks over, one at a time, at a rate of one every 1 hour, 10 minutes, and 42 seconds.

This marvelous device is called a Foucault Pendulum, named for the French physicist Léon Foucault, who created the first of its kind in 1851 to give simple, direct evidence of the earth�s rotation.  How it works, and what it tells us, is the subject of the above video, featuring 91����� Aquinas College tutor and alumnus Dr. Gregory L. Froelich (�83).

�In Sophomore Mathematics we ask the question, �How do we know the earth in spinning on its axis?�� Dr. Froelich begins. From there, he discusses the design and the motion of the pendulum, referencing material from his September 2021 lecture, Science and Freedom. �It�s not the pendulum twisting about, but the floor under the pendulum,� he concludes. �In fact, if the floor, then the whole building; and if the whole building, the whole earth.�