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How does a bull-roarer produce sound when it is whirled through the air?
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wind instrument
The Japanese end-blown flute, or shakuhachi.
The bull-roarer produces sound by disturbing the air as it is whirled around on a string. Unlike many other wind instruments that rely on an enclosed air column within a tube, the bull-roarer is classified as a free aerophone, meaning the vibrating air is not contained.12
As the device—typically a flat piece of wood, stone, or bone—is swung through the air, its movement creates sound waves in the open atmosphere. The resulting howling or whirring noise is determined by the speed at which the instrument is whirled.12