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customcutter
07-16-2012, 11:21 PM
I wonder how hard it would be to build on of these?

http://sciencedemonstrations.fas.harvard.edu/icb/icb.do?keyword=k16940&pageid=icb.page80863&pageContentId=icb.pagecontent341734&state=maximize&view=view.do&viewParam_name=indepth.html#a_icb_pagecontent34173 4

Also wondering how to change all of that to "here".

Ken

randyjaco
07-16-2012, 11:51 PM
Man, that thing makes my dizzy watching it. It probably wouldn't be any more difficult than the old bouncing type, as long as you knew the proper length to hang the balls.

Randy

customcutter
07-16-2012, 11:57 PM
Man, that thing makes my dizzy watching it. It probably wouldn't be any more difficult than the old bouncing type, as long as you knew the proper length to hang the balls.

Randy

Yes, that's the hard part, figuring the mathmatics involved in calculating the string lengths. It might take a few minutes, or maybe years, with trial and error.:eek:

Ken

Evan
07-17-2012, 12:08 AM
There is no difficulty in working out the periods. They describe it there.


The period of one complete cycle of the dance is 60 seconds. The length of the longest pendulum has been adjusted so that it executes 51 oscillations in this 60 second period. The length of each successive shorter pendulum is carefully adjusted so that it executes one additional oscillation in this period. Thus, the 15th pendulum (shortest) undergoes 65 oscillations.

The period calculations are here:

http://hyperphysics.phy-astr.gsu.edu/hbase/pend.html#c2

customcutter
07-17-2012, 12:15 AM
There is no difficulty in working out the periods. They describe it there.



The period calculations are here:

http://hyperphysics.phy-astr.gsu.edu/hbase/pend.html#c2

I'll look at that again tomorrow. It's after 11pm here in sunny central Fl. I don't know what time it is in Kanuckstan(sp). Also, it's been over 40 years since I gradumatated from skool.

thanks for the link,
Ken

aostling
07-17-2012, 12:59 AM
There is no difficulty in working out the periods.


Evan,

You may recall that you previously transformed this pendulum motion to sound, here: http://bbs.homeshopmachinist.net/showthread.php?t=48454&highlight=pendulum

Forrest Addy
07-17-2012, 05:58 AM
Golf balls and 2# test fish line. A staple in each golf ball. Wood frame. You would need a few tweaks to refine sync oscillation.

lynnl
07-17-2012, 01:01 PM
At about the 1:28 or 1:29 time it looks like one or two of the shorter ones are a little bit out of whack (phase).

...but still close enough to be pleasing to the eye.

Evan
07-17-2012, 02:10 PM
I just revisited the audio I created to see if it could be manipulated to produce a more pleasing result. I'm afraid that if one sticks to the basic frequency relationships there is no improvement by slowing or speeding the tempo or changing the pitches proportionately.

It looks much better than it sounds.