Attempt 1: Pink Balloon

Our goal was and still is to achieve really sweet examples of cymatics. Wikipedia defines cymatics as "the study of wave phenomena. It is typically associated with the physical patterns produced through the interaction of sound waves in a medium." We had seen examples of this in our Acoustics Labs, but we sought for even cooler examples of this. We were particularly inspired by a video by Hans Jenny, "Cymatics: Bringing Matter to Life Through Sound" available here, & a highly informative website for DIY Cymatics.

Our set up was pretty simple. We borrowed a oscillator from Mathew Deady (holler), hooked this up, via some broken RCA cables, to my Mackie mixer, and then hooked this up to an amplifier.

We decided it “best” to take apart a small guitar amplifier of mine, a cheap Fender Champ. With the grill and speaker taken out we arranged the amplifier so that the speaker could rest inside the hole that it used to be mounted behind.

(What have I done?!)

This way, we could stretch the balloon over the speaker, duct tape all cracks and holes in the cabinet of the amplifier, and, theoretically, any substance placed on the balloon would either vibrate in a standing wave, or fall off of the speaker onto the amplifier’s surface. We hoped that this would keep things neat.

It looked pretty sweet. We figured we were ready to go.

Almost immediately however, we realized that solids, when placed on the balloon, reacted too strongly. The salt did seem to gather in certain places, but we never got a stable pattern out of a standing wave. Even at extremely low frequencies with very small amplitudes, the salt seemed overly excited.
It was time to reconsider our vibrating mediums.

tupperware + a crappy amp + water

We had seen experiments done with liquids, and decided that this would be a more readily controlled environment. After a considerable amount of improvisation, we devised a system in which an old tupperware container (we liked the fact that it was square, round surfaces seemed to produce predictable and boring standing waves, mostly comprised of rings of various number and size) sat atop the speaker. In this way, we could fill our rectangular playground with different liquids without the unfortunate side effects of liquids all over an electrically charged amplifier. Team Thunderclap only likes the thunder. We didn’t want to be struck by lightning.A bird's eye view of the tupperware atop the amplifier. This would be our home for a couple of hours while playing with this.



(Water before being bombarded with sound. Lacks serious coolness).

attempt 2: oil & water

First, we started with water. Around 60 hz, the water suddenly transformed, with numerous polygons disturbing the previously static surface. We assumed that the shapes we got were a product of a standing wave for, at certain frequencies, the beaded polygons seemed to stand still. Doubling the frequency, 120 hz, seemed to produce similar results, but with smaller polygons.


In order to better illustrate this, we dropped a little oil in the very center of our water. We immediately noticed that the resonant frequencies of the oil was dramatically lower than that of water. At 40 hz, for instance, the oil changed, producing a circular standing wave. The water was not effected by such a low frequency. Taking the frequency up to 60 hz, the two mediums switched, with the water now being effected but the oil remaining stationary.

We got bored with water.


Next, we combined oil and vinegar. Besides the obvious effect of having a more colorful substance, we were tickled by the mixing of the two liquids, the volatile nature of the vinegar within the oil, and the overall splatter effect of the two substances. Again we saw the oil create a circular standing wave, but it was a little lackluster. Thus, we moved on. Heads and swords held high.

The Final Attempt: Sweetness

Then, Team Thunderclap stumbled across that which can only be labeled as freaking awesome.



Having mixed cornstarch and water (one of those freakish concoctions that we discovered as children mixing different things together in the toilet) we put it in our tupperware and sweeped from 20 hz- 120 hz. At low frequencies, you can actually see the pulse of the frequency increasing as we move higher and higher in pitch. At about 110 hz, you can see the wave appear to stand still. The video, with its rather low frame rate, actually makes this easier to see. I must say that this, perhaps, is the best example that we got of a true standing wave within liquid. (1:08–1:20 secs)

Revising Our Final Attempt

To better see the waves, we added a little vinegar to the substance for color. Now, we started to get amazing, not to mention beautiful, results.

Our first standing wave with this new colored concoction came at about 58 hz, slightly below our prediction of 60 hz that we had seen in water. It sounds more like shaking than a low frequency, but you can actually see the pulsing within the liquid. While the liquid did not produce perfectly static waves, the video illustrates that there must have been a resonant frequency that had been struck. One important thing to remember is that our tupperware and speaker were both slightly slanted, the tupperware being bent and the speaker having been taken out of its housing. I suspect that, had we possessed a level with which to perfectly balance our vibrating medium, the results could have been even more impressive.

Other frequencies, all below 120 hz, produced astounding results. You can hear our “oohs” and “aahs” in the accompanying video.
At about 14 seconds, you can see the waves emmerge as we take the frequency down for a second, and then bring it back up the resonant frequency. Pretty astounding.

So where do we go with this? There are an abundance of different mediums to try. It would be fun to do a lot more with this. Our equipment was, for the most part, improvised toys. Using professional equipment (that might actually be flat, how luxurious) I imagine that we could get even cooler results.
One major regret that both of us had was that we only tried sine waves. Square waves and triangle waves would have been really interesting, especially when using liquids. Sine waves, after all, seem a little too friendly with liquid, both being so smooth and curvy.
We encourage all who read this and see our results using rather pathetic means to try and do better. Seriously. There isn't necessarily something significant left to learn in cymatics, but how can you look at this without wanting to get your own results? Surely you could do better.