Singing Mirror

When you tap the mirror, the whole sheet starts to vibrate. Those vibrations push on the air around it, and that moving air is what reaches your ears as sound.

A mirror this size is thin and wide, so it rings in many ways at once — high tones and low tones layered together, arriving and fading at different rates. That is what gives it a gong-like voice rather than a single clear note.

Watch the reflection while it rings. The image shakes because the surface itself is moving. Sound is usually invisible; here you can see it.

Tap it softly, tap it hard, tap it in different places. Each spot sets the mirror moving in a different pattern, and each pattern has its own sound.