# VIDEO: Pendulum Waves

Let me start off by saying that if you are prone to motion sickness, this might not be the best video for you. With just 15 beads attached by string to a beam above, this incredible trick is just out of control! I can’t believe this is actually possible. These pendulum waves create intricate designs one after another. All I could do is wonder what was coming next. Take a good look at this work of art and lets see who can figure out how its all possible.

I mean it starts off going in a wavelike motion, but then it takes an entirely new direction and starts spiraling around with the numerous beads going in all different directions. The beads start swaying from side to side before forming into two lines and create a wonderful back and forth design. Just when you think you have it figured out, the beads end up separating into individual units and sway in an entirely different motion! Next thing you know, the beads are swaying in a few groups before they join together and start the motion all over again.

How is it that these pendulum waves are able to do all of these different motions with just a single swipe of the beads to get them started? I don’t know about you, but I have yet to figure out how this whole thing works. It had me the minute the beads started doing all different movements and swaying in a variety of different ways. These pendulum waves perform so many different movements that it’s hard to keep up with them all. What are your thoughts on this? Would you consider it as an optical illusion? This video is definitely ideal at keeping the kids and pets entertained and amazed.

## 7 Replies to “VIDEO: Pendulum Waves”

1. Alex says:

It happens because the oscillation period of a pendulum is proportional to the square root of it’s length. In that assembly, each pendulum will have a slightly different frequency and the phase difference between them will vary on time, and will be “visible” on the different patterns we observe.

2. Christian Hilton says:

Definitely cool – but it’s merely a frequency of one in ratio to another, clearly there is an exact science at work – like a note’s octave, say the 12 fret on the A string, it’s at a certain point and the frequency is 440hz. There’s a point during the video where it all seems to revert to the initial motion but some are a little off, appearing like a bump – essentially the same as being out of tune – further calibration would correct this. Would have like to have seen it from start to completely finished.

Also compare the wave effect you can apply in an image editor, with frequency and amplitude settings – a single black line on a white background with the adjustment for whether the line is vertical or horizontal will do to get you started.
…The result may be not much to look at, but save it [e.g. image01.jpg] and undo the effect then apply again with another setting – make about ten ‘frames’ in this way changing the setting some more each time,
e.g.
image01 – freq=10
image02 – freq=20
image03 – freq=30
image04 – freq=40
image05 – freq=50
image06 – freq=60
image07 – freq=50
image08 – freq=40
image09 – freq=30
image10 – freq=20
image11 – freq=10

…and compile them together as a gif animation that opens them all in a sequence – use a frame rate of about 4 to 8/100ths of a second so it’s changing faster than your eyes can see and the result is a smooth wave like effect…
Spend a while and you can get some great results
Here’s a slightly more detailed one (100 frames)

3. Jazzizhep says:

I would love to see that same demonstration in a vacuum with an ultra low friction set up. Perhaps the pattern will eventually repeat from the beginning (i am sure there is a mathematical way determine if/when it repeats, but it is well beyond my capabilities and not nearly as fun). I would also like to see the demonstration from different angles simultaneously.

4. Christine says:

Wow! That’s really cool!

5. Chris Smith says:

It has everything to do with the frequency each ball swings at. The shorter ones swing faster and slow down more quickly while the longer ones swing slower and take longer to lose their momentum.

6. suor de sapo says:

wait until the and click on the “blue in the dark” related video

7. wolfwoman says:

I don’t understand any of the scientific explanations. But I am always amazed that such beautiful and fluid patterns are all based on mathematical formulas.