Musical Pendulum Built From Wood & Bowling Balls in North Carolina Mountains

Musical Pendulum

This amazing demonstration of a pendulum made from wood and bowling balls actually makes music. This is absolutely mesmerizing to watch and strangely hypnotic. It sucks you in and grabs your attention. This is an AWESOME physics demonstration and kids will love it!

Musical Pendulum

Published on Sep 7, 2014

“I did not make this – I simply took a video of it! This is a large-scale demonstration of the interaction between period and pendulum length, using 16 bowling balls hung from a wooden frame.

Here are answers to some common questions:

** What am I seeing? How does this work? ** 
The length of time it takes a ball to swing back and forth one time to return to its starting position is dependent on the length of the pendulum, not the mass of the ball. A longer pendulum will take longer to complete one cycle than a shorter pendulum. The lengths of the pendula in this demonstration are all different and were calculated so that in about 2:40, the balls all return to the same position at the same time – in that 2:40, the longest pendulum (in front) will oscillate (or go back and forth) 50 times, the next will oscillate 51 times, and on to the last of the 16 pendula which will oscillate 65 times. Try counting how many times the ball in front swings back and forth in the time it takes the balls to line up again, and then count how many times the ball in back swings back and forth in the same time (though it’s much harder to keep your eye on the ball in back!).

** Why are they not perfect at the end? ** 
This large frame is built from wood and is outdoors, which means it expands, contracts, and flexes. Because the position of the frame changes, the cycle lengths are not perfectly aligned. Variable energy loss due to air friction and the striking of the pipe at the bottom (which creates the music) also contribute to differences. Over time, the minor differences become more pronounced.

** Where is this? ** 
This was built on private property in the mountains of North Carolina (United States), near Burnsville. It is not open to the public. Visit a science museum near you – they may have a similar demonstration!

** Can I get a copy of this video to use in my classroom? ** 
You are encouraged to use this video for educational purposes! If you are sharing online, please provide a link back to this video. Contact me if you want to use the video in other ways or if you need a higher-quality version. This video is available under Creative Commons license BY-SA:…

** How can I make my own? Where can I learn more? ** 
Here are some links to information about the physics behind this demonstration. There are some small scale versions of this demonstration that can be purchased commercially as well, but if you want a 20’ version like this, you’ll have to make your own! I didn’t make this and I don’t have the plans for it, but work through the information at these links and design your own – you’ll learn a lot about physics, math, and construction!
— http://sciencedemonstrations.fas.harv…

***If you’ve read this far, will you do me a favor?***
Go to this link and vote for JJ to be the 2014 American Hero Dog:…
JJ is a very special little dog who protects a very special little girl named KK’s life by doing something just as magical as what you see in this video: JJ detects when KK is having a potentially life-threatening reaction, before any medical equipment can detect it. It’s hard to believe, but it’s absolutely real. I’ve seen it myself many, many times — but what’s more important is that her doctors have seen it, and they were so convinced that they invited JJ into surgery at Duke Medical Center last December! You can learn more about JJ at But please vote! The contest ends on September 15th and you can vote every day until then. If you like JJ’s Facebook page, you can get a picture and reminder in your newsfeed every day:
Thank you!”