### Patterns - Even in Sound!

 Resonance Sound Experiment
As you know, all math is based on patterns.  In fact, patterns are everywhere.  This year, my husband is going to do an experiment with his students on sound and vibration.  He was looking for some ideas on You Tube, and came across The Amazing Resonance Experiment.

If you click under the picture on the left, you will see an incredible thing happen when salt is put on the surface of a metal plate connected to a tone generator and then vibrated with different sound frequencies. Different patterns emerge in a seemingly graceful dance.  As the plate vibrates at different frequencies, the salt particles fall into different resonant﻿ patterns.  It is mind-boggling how the frequencies create such detailed and meticulous patterns of the salt grains. When the video began, I﻿ expected all of the patterns to be symmetrical, but many were not (although, as a mathematician, I thought they were trying!).  I do think it is beautiful how one pattern morphs into﻿ the next. Notice how the patterns become﻿ more complex as the tone increases in frequency.  Also take note of how the individual shapes (circles, squares,﻿ etc.) that form the patterns keep getting smaller and smaller as the frequency becomes higher.

According to physics, everything is frequency and vibration. "These salt patterns are a result of micro bendings in the material due to the vibration waves going through it. The salt gathers at stationary points on the plate where there is the energetic most convenient place. In other words, the salt gathering results﻿ from vibrating the plate at different frequencies.  However, the patterns are not connected solely to the frequency, but rather to the frequency﻿ combined with the shape of the metal plate.  Using the same frequencies on differently shaped plates (round, triangular, etc.) would produce different patterns. Even changing the material would affect the result." The experiment has been tried with flour, sand and sugar with the flour forming clumps (not a desired result).

So take five minutes to watch the video and see the﻿ shape of sound which is beautiful, remarkable as well as fascinating !  Don't you love science?  It's﻿ just as amazing as math!!