Show Details

Sound Laser

November 22, 2005

One listener asks: Can sound be directed into a beam, like a laser? The answer might surprise you.

Transcript

BOB HIRSHON (host):
A spotlight of sound. I’m Bob Hirshon and this is Science Update.

Skye Williams of North Potomac, Maryland, asked us whether sound can be directed into a beam like a laser.

Well, Skye, acoustician Jim West of Johns Hopkins says yes. New devices that project clear, focused sound beams are coming on the market. They work by generating ultrasonic waves, which move in a line instead of spreading out. The ultrasonic waves then beget lower-frequency sound waves that we can hear.

JIM WEST (Johns Hopkins University):
And so the audio frequency sort of rides on this high-frequency sound more or less like radio waves. And if you’re not in the beam you don’t hear what’s going on.

HIRHSON:
These devices are already being used in museums, advertising, and the military. If you have a science question, call us at 1-800-whyisit. I’m Bob Hirshon, for AAAS, the science society.