Pendulum Honors Professor Emeritus, Puts New Spin on the World

Following dedication of the Engineering Building and Physics Addition on Oct. 13, physics alumni, students and faculty will gather in the new physics atrium to honor one of their own.

As they officially name a pendulum for Lawrence Hadley, emeritus professor, the pendulum will maintain a straight line as the audience spins around it.

The device at the center of the celebration is called a Foucault pendulum, invented in 1851 by French physicist J. B. L. Foucault..

Knowing that a pendulum always moves in a straight line, Foucault reasoned that the apparent turning of the pendulum’s plane was in fact due to the east-to-west rotation of the earth underneath it.

The Foucault pendulum dedicated to Lawrence Hadley is suspended by a 25-foot cable, with the ball at the bottom weighing 265 pounds. Built by departmental staff members Dave Warner, Bob Adame and Jay Jablonski, it swings back and forth clockwise over a polished stone compass rose set in the atrium’s floor. A device at the fulcrum in the ceiling gives the pendulum a magnetic "kick" to overcome air resistance and keep it moving.

For Hadley, who taught at Colorado State in 1947 and again from 1955 to 1982 and who remains active in department affairs, this will be the second Foucault pendulum he’s seen in the physics department-although the first named in his honor. The first device was in the original building, built in 1957, that now has been renovated.

Hadley was a Kansas native and high school student when Louis Weber, then a physics professor at Friends University, went on the road in an old car full of physics equipment and presented lecture-demonstrations for high school students. Hadley was taken enough with the subject to earn a bachelor’s degree from Friends University, a master’s from the University of Oklahoma and a doctorate from the University of Michigan in 1947. Weber, who had 10 years earlier become chairman of the Colorado State physics department, hired his protégé for a year (1947). Hadley taught at Dartmouth College but returned to Colorado State in 1955

Hadley specialized in solid state physics, thin films, optics and acoustics and related matters but taught everything. Again, his model was Weber

"He was an excellent teacher and I tried to follow in his footsteps," Hadley said. "Weber was really a very strong influence in my life."

As to having Colorado State’s second Foucault pendulum dedicated to him, Hadley said, "Well, I’m honored. It came as a complete surprise to me."

It is Hadley’s commitment to students and to physics that is being honored, said James Sites, chairman of the physics department.

"His professional specialty was and is dedication to Colorado State’s Department of Physics and to the educational process by which students learn science," Sites said.

The pendulum was funded with private donations to the Department of Physics.

A live web cam of the pendulum can be seen at or