Grades K–2 · Arts & Music
How can a music box play a tune without fingers?
A tiny music box can play a whole tune even though nobody presses piano keys. Inside, a turning drum carries little pins. The pins are arranged to play the notes in a chosen order.
Beside the drum sits a metal comb. Its teeth are little strips of metal, not teeth for brushing hair. A pin catches a strip, bends it a little, and lets it go. The strip wiggles very quickly. That vibration makes a musical sound.
Follow the pin to the free end of one tooth. The dashed tooth shows another position during its vibration.
Different strips make different notes. As the drum turns, each pin reaches its own strip at the right moment. Pins placed together can make notes sound together. Gaps between pins leave time before the next sound.
A handle or a wound spring can turn the drum. The pin pattern carries the tune, while the moving strips make the sound. The box has a wonderfully small way of remembering which note comes next: bumps in just the right places.
About this explanation
The drawing shows one simplified arrangement; real instruments and performances vary.
Starting knowledge: Notice that movement can make sounds and that musicians can play together.
Sources
- Nidec Instruments — Music Movement