Pendulum Waves

Thanks to Desiree for this find.

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

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.

About Kylie Sturgess

Kylie Sturgess is a Philosophy teacher, media and psychology student, blogger at Patheos and podcaster at Token Skeptic. She has conducted over a hundred interviews including artists, scientists, politicians and activists, worldwide.
She’s the author of the ‘Curiouser and Curiouser‘ column at the Committee for Skeptical Inquiry website and travels internationally lecturing on feminism, skepticism, and science.

  • http://stripeyunderpants.blogspot.com/ silverbuttons

    Beautiful and mesmerizing!

  • Hank Fox

    Whoops. I discovered and posted this too, on Blue Collar Atheist. I swear I didn’t steal it from you.

    On the other hand, I now know you have cool things worth stealing. :D

    • Kylie Sturgess

      Hope you stick around for more reading!

  • Francisco Bacopa

    Tried figuring out the math on this; Failed! Its not that it’s that complex, it’s just that there’s so much of it and I can’t figure out a way to simplify the problem.

  • jnorris

    I hope you can get enough of these made in time for the Christmas toy rush.