# Twelve notes

Why does the piano have twelve notes in each octave? If you build notes by going up in fifths, after twelve steps you come back very close to where you started, so twelve notes make an almost closed circle. Twelve is also small enough to fit under the hands. Fewer notes would give poor fifths, and many more would be hard to play and to learn. On the keyboard, the seven white keys come from the first seven fifths, and the five black keys fill the gaps with the next five.

Connects to:
- [Continued fractions](https://mapideas.org/i/mu_contfrac)
- [Temperament](https://mapideas.org/i/mu_temper)
- [The fifth](https://mapideas.org/i/mu_fifth)
- [Pentatonic and diatonic](https://mapideas.org/i/mu_scales)
- [Clock arithmetic](https://mapideas.org/i/mu_clock)

Sources:
- [Wikipedia: Equal temperament](https://en.wikipedia.org/wiki/Equal_temperament)
- [What is music? Module 6, why the octave has twelve notes](https://sofiagallego.com/what-is-music/)

Source: https://mapideas.org/i/mu_twelve · open on the map: https://mapideas.org/#mu_twelve