Is It Possible to See Sound?

Welcome to Cymatics

Cymatics is the study of wave phenomena and its visual representations. It is commonly used in the study of sound waves, as light waves are just a little easier to see.

How are pictures like this possible?

After reading about cymatics, musical artist Nigel Stanford got the idea of making a music video in which the audience could see what they were hearing. One of the methods he used was sand on a Chladni Plate. This is a metal plate hooked to a speaker which vibrates when sound is introduced. The sand grains shift into place depending on the location of the nodes and antinodes of the sound waves. Pictures like the one above could be produced with some fancy lighting and water in a container hooked up to a speaker. Check out what Nigel Stanford was doing for his music video here.

How does sound work?

Let’s take a look. Sound can be conceptualized as density or pressure fluctuations in the air, or as a wave. In discussing most sound phenomena, seeing it as a wave is much simpler.

Some quick vocabulary:

  • Crests- Peaks of the wave
  • Troughs- Lowest points of the wave
  • Waveform- What a wave looks like
  • Wavelength- Distance between two crests or two troughs
  • Medium- Something through which the waves pass
  • Frequency- How many wavelengths pass the same point per second, measured in Hertz (Hz)
  • Amplitude- Height of wave from equilibrium point to crest or trough
  • Superposition- Multiple waves combining and interacting
  • Interference- The effect of superposition (constructive or destructive)

What about standing waves?

Now that we have some vocabulary under our belts, let’s look at standing waves like the one shown above. A standing wave is formed when one wave bounces off of something and reflects directly backwards. Waves don’t always reflect perfectly like above, but for cymatic purposes, we’ll focus on ones that do- standing waves. Nodes are points in which the amplitude is 0, and the antinodes are places where the amplitude is a maximum. If you ever performed an experiment in high school physics with a plastic tube full of air and a tuning fork, this all should sound familiar. The nodes are where the sound is loudest (fun fact: this point is called a harmonic).

Imagine these waves passing through and reflecting inside the thickness of a plate of metal (or any medium). The points in which there would be the most vibration would be the antinodes. At these locations, the sand on the plate would move away to areas of less vibration- the nodes. When we factor in additional waveforms interfering with each other, the possibilities are endless! You can make any shape you want! But with these 2D waves, cymatic shapes can only get so complicated, right?

Is sound really 2D?

I hate to break it to you, but sound isn’t this simple. Sound is 3D, not 2D. 2D waves are a simple way to conceptualize and graph sound waves, but a single sound “wave” is actually a sphere propagating from the source of the sound. I.e., sound is a bunch of spheres interacting with each other. The wave interpretation should not be disregarded, however, as this is still an accurate representation of sound phenomena used in everyday applications from GPS to radio stations.

So take a look at the first picture again and just reflect on the fact that it is possible to make images from sound. Many things seem to be impossible at first, but just remember that people used to think space travel was ridiculous. Sound can be just as visible as it can be audible.

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