If you blow across the top of an empty bottle you'll hear a clear, steady note. Now, engineers have used that same concept to power tiny robots that move without a single motor on board.
These new devices are powered entirely by sound. When the right frequency is aimed at them, hollow chambers built into their structure resonate and push out a jet of air, generating enough thrust to steer a small boat or lift a tiny flying robot off the ground.
The scientists described their innovation in a study published Aug. 12 in the journal Science Advances.
A 19th-century tuning trick, miniaturized
The effect behind it, known as Helmholtz resonance, was first studied in 1856 by the German physicist Read Entire Article
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