Foucault Pendulum Google Doodle for September 18th

Google's Foucault Pendulum doodle for today is an animation that shows the current time according to pegs that have been knocked down by a swinging pendulum, in commemoration of Jean Bernard Léon Foucault's birthday on September 18, 1819. It is very cool. After watching its motion over a period of many minutes, the update appears to occur only when the web page is refreshed, rather than with real-time action. I also noticed what looks like an error in the displayed position of the pendulum on the near side of the peg array that is illustrated in the screen capture below. Unless the pendulum has just been released, it is impossible for the path to lie between two standing pegs.

The pendulum bob's path should never pass between two standing pegs unless it had just been initially released.

Probably most widely seen Foucault Pendulum is (or was) at the Smithsonian Institution's National Museum of American History, in Washington, D.C. I remember seeing it during a class field trip when I was in the 6th grade (Annapolis, Maryland). When Melanie and I took our kids to see the museums back in the 1990s, the most of the building was closed to the public due to renovation, so we didn't get to see it. As it turns out, the pendulum was removed from display in 1998. Bummer. There are, however, many other locations in the U.S. and around the world where very nice Foucault Pendulums are in operation. It is mesmerizing to stand and watch a big one in action. Even the little-known Besser Museum in Alpena, Michigan, has its own Foucault Pendulum.

I remember many moons ago in the late 1970s when I was working as an electrician prior to entering the USAF, I made a service call to St. John's College in Annapolis, Maryland. There, in a pit in the basement of the Observatory building, was a functional Foucault Pendulum. Its cable was attached to a point at the ceiling of the building's fourth story. At the time it had only been less than a decade since seeing the one at the Smithsonian, and seeing it really made my day. A restoration project was begun by the Class of 2011 (see their Facebook page and a real-time stream).

Oh, if my memory serves me correctly, the service call had to do with an outdoor lighting circuit that kept blowing a fuse. It was an 18th century building with knob and tubing wiring in many parts of it, and circuit breakers had not been installed yet. The problem was caused by a short inside a section of buried galvanized conduit. Navigating through a nasty section of crawl space that was filled with nasty cricket spiders, slugs, cockroaches, and every other type of Indiana Jones and the Temple of Doom critter had a lot to do with my decision to make a trip to the Air Force recruitment office.

Click on the clock icon to display slider controls for time and time zone.

After September 18th, look for the Foucault Pendulum doodle on the archive page.

Video of the Foucault Pendulum at the Besser Museum in Alpena, Michigan

(very nicely done by Mary Beth Stutzman)

Posted September 18, 2013