The "Singing Sands" of Lake Michigan

"The sands near the water's edge, in dry weather, emit a peculiar but definite and unmistakable sound when the foot of the pedestrain pushes through them in an abrasive way. This unusual sound from an unusual origin is a source of great delight to children and an inciter of the curiosity of their elders, who, however, rarely pursue the subject far enough to arrive at an explanation for it." (From W.D. Richardson, "The Singing Sands of Lake Michigan," referenced below )

"The combination of quartz crystals, moisture, pressure, and friction from your feet creates a musical tone - a clear ringing sound of singing sand." (http://www.savedunes.org/html/nlsdoc1.html)

"Singing Sand" is a relatively rare occurance on Earth, and Lake Michigan happens to be one place where you can hear it for yourself. Have you noticed that only the sand near the water makes noise? After walking about thirty to one-hundred feet away from the water's edge, there's a definint line, beyond which the sand doesn't "sing" anymore. And did you know that on Lake Michigan beaches, nine out of every ten sand grains is quartz?

There are two theories about why the sand squeaks when you walk on it: one theory from W.D. Richardson in 1919 is that a thin film of salts (including calcium and magnesium carbonates) is deposited on the sand from Lake Michigan. This film creates considerable friction when rubbed and and causes sound to be emitted. Click here to read this theory. 3 pages.

A more recent theory from Sholtz, Bretz, and Nori in 1997 is that the sound results from non-linear oscillations of dispersive stress along the sand's shear plane. If you understand what that means, perhaps you could explain it to the rest of us... Click here to read this theory. 17 pages.

"[Lake Michigan] dunes are to the Midwest what the Grand Canyon is to Arizona and Yosemite to California. They contribute a signature of time and eternity."   Carl Sandburg