Here's why:

* Vibrations create sound waves: Vibrations cause the particles in the surrounding air to vibrate as well. These vibrations travel outwards in waves, which we perceive as sound.

* Frequency and pitch: The speed of the vibration (its frequency) determines the pitch of the sound. Faster vibrations create higher-pitched sounds, while slower vibrations create lower-pitched sounds.

* Amplitude and loudness: The strength of the vibration (its amplitude) determines the loudness of the sound. Larger vibrations create louder sounds, while smaller vibrations create softer sounds.

So, next time you hear a sound, remember that it's caused by something vibrating!