Whistle

A whistle is a musical instrument which produces sound from a stream of gas, most commonly air.

Whistles have been around since early humans first carved out a gourd or branch and found they could make sound with it.

The conversion of flow energy to sound comes from an interaction between a solid material and a fluid stream.

Boatswain pipes were also used in the age of sail aboard naval vessels to issue commands and salute dignitaries.

[5] In 1883, he began experimenting with pea-whistle designs that could produce an intense sound that could grab attention from over a mile away.

Observing how the discordant sound of the breaking strings travelled (trill effect), Hudson had the idea to put a pea in the whistle.