Singing sand
Singing sand is
sand that
emits sounds of either high or low
frequency under pressure. The sound emission is usually triggered by wind passing over dunes or by walking on the sand. The sound is generated by shear stress.
Certain conditions have to come together to create singing sand:
- The sand grains have to be round and between 0.1 and 0.5 mm in diameter
- The sand has to contain silica gel
- The sand needs a certain humidity
The most common frequency emitted seems to be close to 450
Hz.
Other sounds that can be emitted by sand have been described as "roaring" or "booming".
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