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Old Aug 23, 2006, 3:52 AM   #1
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I had a hard time getting the right exposure here, because the pendulum (as it's name says) made really very chaotic movements.



They had a little blue LED on the "loose" pendulum arm so you can guess/see the motion even better.

A bit more "action" on the 2nd shot (I won't give you the ones with real long exposure, the pendulum is barely visible on those, but nice blue rays of the LED )



Now I know this challenge is limited to 2 pics per post, just say a word and I'll delete the 3rd one, this is only to show you what the pendulum looks like without much motion, you can see the fixed and the rotating arm better that way:



You can lookup the theory behind this experiment, there are other "chaotic" things like this.

Enjoy!
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Old Aug 24, 2006, 7:03 AM   #2
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Interesting shots. I think I prefer the top one.
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Old Aug 24, 2006, 12:08 PM   #3
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The middle shot comes closest to showing the chaotic motion you were aiming at.

As vsch1 says an interesting series.

Aloha
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Old Aug 28, 2006, 7:15 PM   #4
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An interesting series of photos, indeed. I have seen one of these clocks somewhere but I don't recall exactly how the pendulum moves. Could you explain it so that my 61-year old brain can understand it. Then, once I understand it, I have to go out and buy one!

Cal

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Old Aug 29, 2006, 7:04 AM   #5
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@Calr
Well - it's not a clock to show the time... although it looks a bit alike. You may get the idea looking here (Java required), this is like half of "my" pendulum (the half with the moving arm):

http://www.myphysicslab.com/dbl_pendulum.html

The chaotic pendulum (CP) my pictures show consists of a center arbor/staff in the center where the pendulum itself is mounted.

The pendulum consists of a long arm in the middle and a fixed (90°) arm on one side. The other arm (the one with the LED) can rotate freely. Picture #3 shows the fixed arm on the left and the moving arm on the right.

When you turn the arbor the fixed arm stays in position but the moving arm gives its impulse to the whole construction PLUS the pendulum itself moves around the arbor.

The result is a chaotic movement of the pendulum. Try the link I gave and drag the pendulum there with your mouse to different starting position and watch it a while...

I am really sorry, it's a bit hard to explain since I am not a native speaker when it comes to english, I hope it helps what I said and makes some sense to you.

I add two more pictures to show a more chaotic behaviour - with all the explanation one can now understand and maybe appreciate them - but without any explanations they are not for "public viewing" to say so. Watch the traces of the blue LED!





Regards,
Th.
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