The world’s biggest Foucault pendulum

The world’s biggest Foucault pendulum has been within an easy day trip of Seattle for more than 20 years. Despite being a frequent visitor to Portland, Oregon, I never knew about this wonder of the Rose City until I stumbled upon it this week.

Spires of the Oregon Convention Center

The world’s largest Foucault pendulum swings inside the north tower of the Oregon Convention Center in Portland. Photo: Greg Scheiderer.

I was in Portland for the annual conference of an organization called Net Impact. The gathering was held at the Oregon Convention Center, distinctive and noticeable from all over the city for its twin, 320-foot glass spires. Hanging inside one of them is “Principia,” a Foucault pendulum that swings 20 feet above the convention center floor from the end of a 70-foot cable.

Foucault pendulum, Oregon Convention Center

A bird’s-eye view of “Principia,” the Foucault pendulum at Oregon Convention Center. Photo: Greg Scheiderer.

OCC claims to be the largest convention center in the Northwest, and “Principia” is part of the center’s art collection valued at more than $2 million. As a testament to the size of the building, I hadn’t even seen the pendulum until the third day of my conference. It was way around the building and up another wing from where Net Impact was meeting. I likely would not have seen it at all had I not opted for a nice long walk after lunch on Saturday.

There’s some disagreement about the weight of the 36-inch diameter sphere of the pendulum. A plaque near the installation says it weighs in at 750 pounds, but the website of the artists who built it, Kristin Jones and Andrew Ginzel of New York, puts it at 950 pounds. At any rate, it is big and heavy. The pendulum swings just above a suspended gilt crown 40 feet in diameter. The blue terrazzo floor is spectacular, inlaid with brass rings and colored stone planets that depict a fantasy solar system. It was all installed in 1990 when the Oregon Convention Center was first built.


A detail of the floor. Photo: Greg Scheiderer.

I shot a quick video of the pendulum with my iPhone camera, and that’s posted below. You can get a much better-quality look at it on the convention center’s 360 tour. It’s a flash feature and the link doesn’t go directly to the Foucault pendulum. When you get there select “exhibit spaces/Exhibit Halls A and B – Pre-function lobbies” from the green tab in the menu on the left of the page. And you can find a bunch of photographs that are a bit better than mine on the OCC Flickr page.

It’s pretty spectacular. Definitely worth a look the next time you’re in Portland.