plastic whistle

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It was a little whistle that controlled the audience
For fans, the most heard on the court, in addition to the shouting of mountains and tsunami, must be the referee's whistle. Modern whistle is mostly made by plastic manufacturers.
People who have played the whistle should have the impression that there are many small balls in the whistle. The small balls will jump under the action of the air flow, the frequency of sound will also change, and the whistle will change.
And this type of whistle with a ball has a more "professional" name-the pea whistle. It was invented by an inventor named Joseph Hudson around 1884
The whistle originally appeared as a musical instrument or toy. The referees never thought of using a whistle. At the time of the football game, the referees were not holding a whistle, but a handkerchief. They controlled the game by waving a handkerchief. Joseph's client was not a referee, but-the British police. It was later used in competitions and has been used to this day, becoming the most widely used whistle in the world. If you want to own a whistle, you can buy it from a party supplies manufacturer