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2023-12-23
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A 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 2023) 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 [hh:mm:ss.ms].