Foucault Pendulum, Introduction            vlag_nl.gif                           Latest change 2019-12-15


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FoucaultAnimation.gifA Foucault Pendulum consists of a thin wire on which a weight is suspended. The weight can swing freely in any direction, and suppose it is swinging in East-West direction at a certain moment, a few hours later it will swing in another direction because the earth is rotating below it.(*)
The behaviour of a Foucault Pendulum gives a rather direct evidence that the earth is rotating.

The challenges are:
 - Mounting and driving the pendulum such that there is no preference for a certain direction.
 - Suppressing the elliptical orbit any free hanging pendulum tends to develop.
 - The technique for tracking and logging the behaviour of the pendulum.
 - The web technique to stream real-time images and to present the logged data.

My plan was to:
 - Build a pendulum in my home and evaluate the requirements for driving and tracking (winter - summer 2016/2017)
 - Mount a pendulum in the Chapel at Vrijland. Here we can implement the web-technique.

(dec 2019) Due to all kind of circumstances the work has been delayed severely. The setup in the Vrijland Chapel became a once only experiment and it is now sure that there will be no follow-up there.

Here is a short movie of the pendulum at my home.

(*) Only at the North- or Southpole the plane of swinging will rotate in 1 day(**). At lower lattitudes it goes slower, with 1/sin(lattitude) and on the equator it does not work at all because sin(lattitude) will be zero and the swinging plane will take infinite time to rotate.
(**) This is the siderial day, that is the time in which the earth makes one revolution w.r.t. the far, fixed stars. That time is 23:56:04.140 [].