LIFT A SHELL from the sand to your ear and everyone knows you can hear the sea. But listen carefully enough and you can hear shells in the sand too. Sand, it turns out, has a signature sound of its ...

"And it's a sound that's very similar to kind of the tones you'd get on a cello." Melany Hunt, a mechanical engineer at Caltech. The dunes sing when sand avalanches down the side, "which would then be ...