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As of march 2025 details of the new Sub-Meter pendulum are available.
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 severely delayed. The setup in the Vrijland Chapel became a once only experiment and it is now sure that there will be no follow-up there.
Nevertheless I continued improving my pendulum. Whether it will result in a publically accesible pendulum .. I don't know.
Here is a short movie of the pendulum at my home.
And below is the trajectory of the pendulum during a full precession period. (30.4 hrs in NL)
Time lapse at 5 minutes interval.
This is not simulated, this is Real Data from a Real Pendulum.
(*) 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].
Who Am I
My name is Jan Breemer.
I am a retired electronic technician living in the Netherlands, region Betuwe.
During my (payed) working life I gained also some knowledge in the fields of medical Xray equipment, medically used radio nucleïds, optics and machine control.
As hobby I do things in the fields of hifi sound reproduction for in the home (but without the nonsense often sold in that field), domotics, machined metalworking, all kinds of DIY in and around the house, and I assist with sound and lighting for an amateur theater group and a cultural institution.
I am also participant in the HackerSpace Hack42 in Arnhem, NL where I am involved with a.o. the construction of a large laser cutter, a multi-purpose CNC machine and the setup of the metal workshop.
I knew for decennia about the Foucalt Pendulum, but for some reason I had the fixed idea that only a very long pendulim would work, and that was beyond my reach. Until.... early 2016 at Hack42 the possibility came into view that we could move to the abandoned dome prison in Arnhem.
I was immediately thinking of a pendulum in that dome of 35 m height. From then on I dived into the physics and found that it could be done with a much shorter pendulum too.
The rest is history, and no, Hack42 did not move into that prison.
Websites die ik onderhou / Websites I maintain:
breem.nl janbeeprojects.nl and this site: foucaultpendulum.nl or foucaultslinger.nl
Disclaimer.
All information I present on this site is correct to my best knowledge, but I am not infallible.
You may use all information here for your own purposes, but at your own risk.
If anyone thinks that I illegally use or reproduce certain information, please let me know.
Jan.