Donor's Legacy on Display in New Science Complex
The gently moving jewel swaying inside the new Ernest E. Tschannen Science Complex is a Foucault pendulum—shiny and slow-swinging, it is a piece of old-world technology the likes of which have kept track of the earth's rotation for the last 168 years.
It's a singular attraction in University's state-of-the-art Science Complex, which opened this fall.
The pendulum is a 235-pound polished-brass "bob," resembling a Christmas ornament and suspended by a cable affixed to a pivot point high above. It was bequeathed to the University by a former Sacramento State physics professor.
Chien Yuan Hu, born in China and educated in Taiwan and the University of Missouri, retired from Sacramento State in 1992, after 26 years as a professor of physics. He passed away in December 2001, leaving his nearly $2 million estate to the University. The Chien Hu Physics Endowment funds an annual scholarship for outstanding physics majors.
Hu had envisioned his endowment would be used to purchase a Foucault pendulum to hang in Sac State's new science building. Thanks to Hu's estate gift, this pendulum now finds its home in the first-floor Science Complex lobby, on display for students, faculty and visitors to enjoy.
The pendulum hangs over a flat plate marked with compass points and revolves a full 360 degrees, in the opposite direction of the Earth's west-to-east movement.
"The Foucault pendulum was the first-ever direct evidence that the Earth spins on its axis," says Chris Taylor, professor and chair of the Department of Physics and Astronomy. "People were pretty sure for hundreds of years that the Earth was spinning but couldn't prove it, because it looked like the sky was moving around them."
In 1851, French scientist Léon Foucault published findings of his revolutionary pendulum experiment, ending 200 years of attempts to demonstrate the planet's movement.
"Professor Hu was interested in the history and philosophy of science," says Chris. "It's pretty obvious now, especially after sending astronauts into space, that the Earth is spinning, but in the 1800s and before, how would you know?"