Blown bottle
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A blown bottle is a musical instrument that produces sound when the musician blows air over the bottle opening.[1][2]
Blown bottles generate sound by utilizing a vibrating column of air, a phenomenon known as Helmholtz resonance.[3][4] The bottles may be tuned by adding various amounts of water or sand to the vessel.[5]
Blown bottles, like the musical jug, are sometimes used by performers of folk music.[6] The blown bottle is assigned to note number 76 (or 77, for numbering starting with 1) in the General MIDI specification.[7]