Ever walk along the beach and hear a low hum coming from a nearby sand dune? Or maybe it was a high pitched squeak? How about a loud roar? Whatever was heard, it was simply the music of the sands.
Marco Polo was one of the first people to document the natural phenomenon of singing sands over 700 years ago, however he credited the sounds of the Gobi Desert to evil spirits. Today, travelers might mistake the musically-inclined sand to come from a low-flying airplane.
What causes the Singing Sand?
To put it simply, the music happens when sand accumulates at the top of a dune and spontaneously avalanches down to the bottom of it. In some cases, the singing can come from feet shuffling through the sand, wind passing over it or just moving the sand around by hand.
The sound is generated by the stress and pressure of the grains of sand colliding with each other. The collision causes a synchronized movement among the grains, while the outer layer of the dune acts as a giant loudspeaker as the grains fall.
While some dunes are musically-inclined, are all others tone-deaf?
Not exactly. Certain conditions need to be present at the same time in order to create the music. Each grain of sand has to be dry and round. It also has to be between 0.1 and 0.5 millimeters in diameter. The sand needs to contain silicon, iron and manganese, and the air has to be a specific humidity for the music to occur. In "Singing to the Tune of Sand," a July 12, 2006, article by PhysicsWeb author Belle Dumé, researchers have found that the grains of sand need to be moving at a speed of at least 0.45 meters per second to make a noise as well.
Where is Singing Sand Heard?
Singing sands can be found in nearly 30 locations around the world, including California’s Kelso and Eureka Dunes, the Sand Mountains in Nevada, the Namib Desert in Africa, Porth Oer in Wales and the Indiana Dunes State Park.
Every location is different. Singing sands possess unique frequencies and notes that separate one area from the next depending on the size of the grain of sand. Songs can last for a few seconds, or can go on for minutes and sometimes even hours. In some locations the singing sands are loud enough to be heard from over a half mile away.
Test it out! Grab a friend or family member and take a trip to the beach. Walk through the sand, move it around and listen. Nature might just be playing its song.
Jessica Cochran - I've been writing for print publications ever since I was in high school. Actually, I began writing "articles" when I was eight, forcing ...
