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UB helps pendulum get back in the swing

Physics professor, student help power museum’s Foucault pendulum

Published: August 31, 2006

By KEVIN FRYLING
Reporter Staff Writer

The Buffalo Museum of Science's impressive 75-foot Foucault pendulum is no longer out of commission, thanks to the efforts of a professor and undergraduate student in UB's Department of Physics.

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John Cerne installs the circuit needed to power the Buffalo Museum of Science’s Foucault pendulum.
PHOTOS: NANCY J. PARISI

The project is the first significant upgrade the pendulum has seen since its construction in the 1970s, said John Cerne, assistant professor of physics who was involved in the installation of the electric "kicker" circuit that now powers the exhibit.

"A lot has changed in electronics in the last 30 years," Cerne said. "As long as there's no power outage, the pendulum will run forever."

Prior to the repair, the pendulum never ran more than about eight hours at a time, he pointed out.

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Dan Crowe sets the pendulum in motion. Crowe built the circuit that now allows the pendulum to run indefinitely.

Daniel Crowe, a sophomore who plans to major in mathematical physics, built the circuit this summer while participating in the SUNY Louis Stokes Alliance for Minority Participation (LSAMP) Minority Summer Research Internship Program. He said the circuit he built for the science museum was patterned on the one that runs the Foucault pendulum that was installed this spring in Fronczak Hall as part of a permanent, interactive exhibition. Cerne served as Crowe's mentor throughout the eight-week LSAMP program.

Cerne, who studied the Foucault pendulum at the science museum last spring, and others involved with the Fronczak pendulum selected a more modern circuit for the science museum, based on a pendulum at the University of Louisville.

The LSAMP summer internship program was the perfect chance to turn the idea into an educational experience, said Cerne. The program enables undergraduate students from underrepresented minorities to participate in graduate-level science and mathematics research as part of a summer stipend program. A Native American student involved in UB's Daniel Ackers Scholars Program, Crowe learned about LSAMP through his advisor in Cora P. Maloney College.

Students in the summer program participate in a three-credit research methods course, seminars and other enrichment activities.

"I thought it was a good chance for him to learn some basic electronics and build something that could also be useful," said Cerne.

Crowe worked in the lab next door to Cerne's office and called it a great experience to work "one-on-one" with him. This was not the first time Crowe and Cerne had met, however. Crowe had shadowed Cerne several years earlier as an 11th-grade student from Kenmore West High School.

"I came into this program very young," noted Crowe. He said the pendulum project offered a glimpse into graduate-level activities and hours in the lab while at the same time providing hands-on experience with such basic physics concepts as magnetism, mechanics and electricity.

"A good number of undergraduates do research in our labs," Cerne added.

After a crash course in electronics, Crowe spent most of his time constructing the circuit. He explained that James Burnett, a graduate student in the physics department, designed the original circuit and his role was to build a reproduction.

He said the new-and-improved circuit at the Buffalo Museum of Science eliminates the loss of power that takes place as the pendulum oscillates by using an electromagnet to tug the weight or "bob" and restore momentum. The magnet is triggered in short bursts based on information it receives from two laser sensors. The original circuit at the museum used a less-efficient system that controlled the magnet with broken beams of light, rather than lasers.

Foucault pendulums behave independently of the planet, and therefore the circular progression of their swing is an illusion that reveals the rotation of the Earth. The planet—not the pendulum—is in motion. It is the sole scientific instrument that shows the rotation of the Earth without access to the sky.

Cerne explained that it is significant that the science museum pendulum now runs more than several hours at a time because it takes about 35 hours to trace a complete loop at Buffalo's latitude. This length of time stretches towards the infinite as a pendulum travels from the poles to the equator.

"These pendulums need to run 24 hours a day, seven days a week," said Crowe.

Crowe presented his work on the pendulum as part of a poster presentation at the 12th annual Western New York Ronald E. McNair Research Conference, held last month in Niagara Falls. UB hosts one of the largest McNair conferences in the United States, with more than 350 participants from across Western New York and nationwide. The conference provides a professional forum in which McNair scholars and other undergraduates can present research to faculty, graduate students and peers.

"The main idea is a conference for students to get their first chance at presenting material," said Crowe, who received the LSAMP Character and Leadership Award. "It's a great thing; I liked going and would like to go again."

"I want to keep doing research," he added. "I want to go to these conferences and see people from my field."

The new circuit to run the science museum pendulum was installed last week. All labor and most of the parts were provided to the museum free of charge, said Cerne. Plans are also in the works to provide the museum with informational posters on the pendulum based on those for the Fronczak Hall exhibit, in as well as one on the circuit based on Crowe's poster presentation at the McNair conference.

Cerne noted that most people never realize that physics takes place all around them. With the restoration of the pendulum at the Buffalo Museum of Science, visitors once again can witness with their own eyes that we live on a planet that is in constant motion.