Sunday, May 22, 2016

Foucault's pendulum

French physicist Léon Foucault is credited with the notion that the movement of Earth as it rotates can be perceived in the rotation of a pendulum's plane of oscillation. Can you say that three times, fast? What's French for "bazinga!"?

Foucault's pendulum swings from the center of the Panthéon's impressive central dome. The blurry gold ball is the "bob."

The pendulum in the Panthéon is the oldest surviving of Foucault's original pendula (that is an acceptable plural form!). The actual original, hanging in the museum of Arts et Métiers in Paris, was destroyed in 2010 when its cable snapped. There are many versions of the Foucault pendulum around the world. One of the more famous, and one that I saw as a schoolboy on a field trip, hangs (swings?) in the United Nations headquarters in New York City.


  1. The Foucault's pendulum is certainly one of the best known of the Pantheon's highlights.

  2. The pendulum bob at Arts et Métiers wasn't destroyed, but it has been irreparably damaged. It now sits in a glass case next to the working reproduction. The church at Arts et Métiers isn't its original location either. It's been moved around from the Observatory to the Panthéon to Arts et Métiers (and back and forth between the Panthéon and the Museum at least once).

  3. I missed allllllll of this when I visited the Pantheon. It was all there, but I had no good background to appreciate what I was looking at! I don't think I've been back since I first got to Paris in '81, and I've learned so much since then :) Age is good :)

  4. Saw it on our first trip to France in 2006 as we stayed nearby - We both love that area of Paris. Thanks for a memory flash back Walt.

  5. chm, one among many!

    susan, I understand it busted up the marble floor when it fell.

    judy, my memories from then are sketchy, too. I've got a long list of things I want to see again, especially as many of them have been restored since '81-'82. Versailles and Fontainbleau head up the list now.

    leon, it's a great neighborhood, that's for sure!

  6. we have one at the franklin institute in philadelphia.


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