Learn how the British used sound mirrors to detect enemy aircraft in this video from NOVA: Zeppelin Terror Attack. During WWI, Germany used zeppelins to attack the British. Because the airships flew at night and were impossible to see, the British developed a method to detect incoming zeppelins by amplifying their engine noise. Sound mirrors—concrete structures with a concave surface—could reflect and focus sound waves, allowing a listener to deduce the direction of an approaching airship. An experiment with a sound mirror, microphones, and an airplane demonstrates how the system works to provide advance warning of an aircraft miles away.
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