Pendulum Perfector
Academy could no longer make kept coming
in. “They asked me to take [them],” Ponchione
says of the pendulum orders, and a small business, Academy Pendulum Sales, was born.
A friendly, outgoing machinist and fabricator, Ponchione keeps a spare, tidy shop by
the tracks in Richmond, Calif., where he
assembles pendulum kits for customers to
install. “As you can imagine,” the semi-retired
maker deadpans, “it’s not a full-time job.”
Though he has others join, turn, finish,
and polish the cast brass hemispheres that
make the 235-pound, 16-inch bob, Ponchione
makes and assembles most of the small
parts, and still hand-winds the ring electromagnet, which adds the perfectly timed kick
that keeps each pendulum swinging.
—William Abernathy
If you’ve visited enough science museums,
you’ve seen a Foucault pendulum. Named
after its inventor, French physicist Léon
Foucault, the pendulum demonstrates the
Earth’s rotation by knocking down pins
arrayed around the pit over which it swings.
Although the pendulum appears to swing
around the pit, it’s the pit, and Earth it stands
on, that rotate beneath the pendulum. And
there’s a good chance the pendulum you
know is one of more than 100 made so far
by Cary Ponchione.
California Academy of Sciences
For 34 years, Ponchione worked in the
basement shop of the California Academy
of Sciences museum in San Francisco. Shortly
before moving from its home of 87 years in
Golden Gate Park, the Academy downsized
its in-house exhibit-building shop and offered
early retirement to Ponchione.
» Foucault Pendulums: calacademy.org/products/pendulum
But calls for the pendulums that the
25 Follow us @make
