The pentatonic scale: why every note sounds good
Short answer: the pentatonic scale uses five notes and leaves out the two that usually create tension. With nothing to clash, any order of its notes sounds pleasant, which is why so many folk songs, riffs and children's tunes use it.
Five notes instead of seven
A regular major scale has seven notes. The major pentatonic drops the 4th and 7th, the two notes that sit a half step away from their neighbors. In C that leaves C, D, E, G and A.
Why nothing clashes
Clashing sounds come from notes only a half step apart played together or back to back. The pentatonic scale has no half steps, so even random sequences stay smooth.
Major vs minor pentatonic
Start the same five notes on A instead of C and you get A minor pentatonic: darker, bluesy, great for moody tunes. Same notes, different home.
Hear it in a minute
On a piano, play only the black keys. Or open Doodletune, which uses the pentatonic scale by default: draw any scribble, press play, then switch the scale to major or minor to hear how the same drawing changes mood.
FAQ
How many notes are in a pentatonic scale?
Five per octave. In C major pentatonic they are C, D, E, G and A.
Is pentatonic the same as the black keys on a piano?
The five black keys form a pentatonic scale, which is why playing only black keys sounds pleasant.
Major or minor pentatonic, which should I use?
Major sounds bright and open, minor sounds moody. They share the same five notes starting from a different home note.