* Resonance: The shape of the whistle is designed to create a resonant cavity. This cavity amplifies specific frequencies of sound waves, preferentially amplifying higher frequencies.
* Air Pressure: When you blow into a whistle, you create a fast-moving stream of air. This high-velocity air creates a low-pressure area within the whistle.
* Vibrating Air Column: The air inside the whistle is forced to vibrate as it is pushed back and forth by the pressure changes created by the blowing air. This vibration creates sound waves.
* Frequency: The frequency of the sound waves is determined by the length and shape of the whistle's resonant cavity. Shorter cavities produce higher frequencies (higher pitch). Whistles are typically designed with small cavities, resulting in a high-pitched sound.
* Overtones: Whistles often produce multiple frequencies (overtones) in addition to the fundamental frequency. These overtones further contribute to the overall high-pitched sound.
In simpler terms:
Think of a whistle like a tiny pipe. When you blow into it, you force air to vibrate inside the pipe. The shorter the pipe, the faster the air vibrates, and the higher the pitch of the sound.