Pendulum Waves

Fifteen uncoupled simple pendulums of monotonically increasing lengths dance together to produce visual traveling waves, standing waves, beating, and (seemingly) random motion.

For more details see http://sciencedemonstrations.fas.harv...

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.

Our apparatus was built from a design published by Richard Berg [Am J Phys 59(2), 186-187 (1991)] at the University of Maryland. The particular apparatus shown here was built by our own Nils Sorensen.

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Video courtesy of Harvard Natural Sciences Lecture Demonstrations, © 2010 President and Fellows of Harvard College

• Category

  Education

[Scott Wall]

Nice Effect !

[JoniTheFlipnoteMaker]

Whoa

Kinda reminds me of this:

/watch?v=Q0gs6ykCWis

[Ace0077]

I'm afraid you're wrong, it would eventually stop even in the vacuum. 

[ApertureBlack]

This hurts my eyes

[fracktar]

Well there are many factors in space such as the gravitational pull of planets that would cause it to stop but if we assume it's in the vacuum of space alone, it should eventually stop as the vacuum of space does not contain nothing. In space every cubic meter has 1 hydrogen atom so there would still be friction even though it would likely take millions of years to stop

There are 1062519581046650000000000000 hydrogen atoms in 1 cubicmeter of air here on earth. (rough estimate just worked it out)

[arlon wilder]

Even in the vacuum of space it would still eventually stop? You're teaching me so much, thank you.,

[fracktar]

Pushing through the air creates friction, it is known as wind resistance. Passing through any gas will cause friction it's just barely noticeable until you pick up a lot of speed, but it's always there and this is why the balls eventually will stop. Friction is all just molecules rubbing together whether they are gas, liquid or solid.

It would go for a very long time in the vacuum of space though where there is very little to create friction.

[arlon wilder]

does the wind resistance also create friction?? or are you referring to the slowing process of the weight?

[fracktar]

Also wind resistance