Foucault Pendulum Made in America

Foucault Pendulum Made in America

Local machinist, Cary Ponchione, may not have a degree in physics, like Léon Foucault, whose birthday is being celebrated with an animated “doodle” on the Google homepage today, but he understands the working of the Foucault pendulum better than most. He’s been making the 235-pound, 16-inch bob that demonstrates the rotation of the earth, for over 34 years and his pendulums can be seen in universities, planetarium foyers, and museums throughout the world.  Although Léon Foucault was French, his famous Foucault pendulum design is made by Ponchione in his workshop in California, right here in America.

Ponchione, a metal fabricator, worked for 34 years in the basement shop of the California Academy of Sciences Museum in San Francisco, filling pendulum orders from other institutions. “We would get calls from time to time for a pendulum exhibit and it was my job to create that,” said Ponchione in a telephone interview.  When the Academy moved to a new, smaller location, Ponchione elected to take early retirement, but orders for the pendulums kept coming into the Academy and they called on Ponchione once again to fill them. Now under his own company name, Academy Pendulum Sales, the semi-retired Ponchione provides these beautiful brass pendulums for permanent installations, which are purchased as kits.

Ponchione is much like Foucault, although separated by more than a century, both men are talented at building tools and devices. Ponchione will be the first to tell you, “Foucault was more toward the science of things, I’m more interested in machines.” Sequestered in his workshop in a residential area of Richmond, California, Ponchione assembles the pendulum kits with the help of vendors, who assist in the casting, joining, turning and finishing. “The spheres are complicated to get made. It takes big machines to make these small spheres.” The pendulum ball is made of two hemispheres, dovetailed and secured through a complex heating and cooling process, then welded together to form the hollow sphere. The end caps are then secured separately.

It is Ponchione alone who assembles the smallest parts and hand-winds the important electromagnet that, together with the friction of the air, makes the pendulum swing without stopping. After each pendulum is completed, he tests the precision of each one before sending it to its new home.   The price tag for a Foucault pendulum is $35,000 and all parts are made in America. Besides the polished brass ball with its sculptured end caps, the kit includes a 1/8” cable to suspend the ball, a support tower and pivot, the magnetic drive system and an electronics control package. The kit also features a brass wall plaque on a walnut base with information about Léon Foucault, explaining his contribution to science and how the pendulum works.

With over 90 locations in the Unites States, the Academy Pendulum Sales’ Foucault pendulum is housed in some of the most prestigious museums in the country, such as the Science Museum of Richmond, in Virginia, Museum of Science in Boston, Massachusetts and Denver Museum of Natural History, in Denver, Colorado. Universities to feature the pendulum include the University of Washington, Seattle and the University of Florida in Tampa. Internationally, the pendulums are in Turkey, Scotland, Kuwait, Pakistan, Thailand, and Japan.  Academy Pendulum Sales also offers an online study unit for teachers to help them explain to students what the pendulum means and how it came into being.

The beauty of the ever-swaying brass ball is only surpassed by what it is telling us about the planet on which we live. Although the creation of the first pendulum may have been in the workshop of a French physicist, a local machinist, continues to offer the insights of the Foucault pendulum made here in America.

By Lisa Nance

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