The Mysterious Singing Sand Dunes

… and his hands formed the dry land. Come, let us bow down in worship, let us kneel before the LORD our Maker;  Psalm 95: 5-6

God’s power and wisdom can be seen in the things He created. Nature teaches us about obedience to the will of its creator.

When Marco Polo first heard it in China, he believed it was the work of strange beings. The Chileans named a sandy hill, El Bramador – the roarer or bellower, due to its deep groaning roars. Now, it is called “singing or whistling sand” denoting sand that produces sound.

Sand grains, round and between 0.1 and 0.5 mm in diameter, when sliding down the slopes of sand dunes produce a hum that echoes for miles. The roaring and booming sound or “Song of the Dunes”, can last for more than a minute, usually at a frequency of 450 MHz. People can push the sand downhill setting it in motion, or the wind can trigger sand avalanches, leading to a sudden, squeaking chorus.

New research indicates that it is not the motion of the sand grains that determine the pitch of the note, but it is the size of the grains. Moreover, sand grains of certain sizes tend to produce resonant notes in the range of 90 to 150 Hz or about F-sharp to D, a scale of nine notes.