Why Sand Dunes Go Boom for National Geographic News |October 20,
2004| It sounds like a low-flying propeller plane or maybe the
deep humming of an electric wire. The booming sound made by some
sand dunes has been a mystery for centuries. The sound is
produced when sand on the surface of a dune avalanches.
Scientists have long believed the friction between grains
creates the strange noise. But Melany Hunt, a mechanical-
engineering professor at the California Institute of Technology
in Pasadena, thinks there is something else at play too. For the
past three years she has been taking her students out to the
desert of eastern California and Nevada. By sliding down the
dunes on their bottomsliterally doing science by the seat of the
pantsHunt and her researchers set the sand in motion to measure
the sound waves it makes. They have found that the sound
continues even after the movement has stopped. Also, the sound
that a sand dune makes in winter differs from the sound it makes
in summer. Hunt believes that when th