A scale is a set of notes arranged from low to high within an octave, starting from a home note called the root or tonic. Most Western music picks its notes from a scale, which is why a melody and its chords sound like they belong together.
Half steps and whole steps
The smallest distance on a piano is a half step (semitone): from one key to the very next, black or white. Two half steps make a whole step (tone). On a keyboard, C to C♯ is a half step and C to D is a whole step.
Two places on the white keys have no black key between them: E to F and B to C. These are half steps, and they are the reason the white-key pattern is not evenly spaced.
The major scale
Every major scale uses the same pattern of steps, where W is a whole step and H is a half step:
W W H W W W H
Starting on C, that gives C D E F G A B C: the white keys. Apply the same pattern from G and you need one sharp, F♯, to keep the pattern intact: G A B C D E F♯ G.
| Degree | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
|---|---|---|---|---|---|---|---|
| C major | C | D | E | F | G | A | B |
| Step to next | W | W | H | W | W | W | H |
The natural minor scale
The natural minor scale uses a different pattern:
W H W W H W W
From A this gives A B C D E F G A, again only white keys. Compared with major, the 3rd, 6th and 7th degrees are lowered by a half step. The lowered 3rd is what gives minor its darker character. Natural minor is also the mode called Aeolian; see the article on modes for the others.
Relative major and minor
C major and A minor contain exactly the same notes. They are relative keys. The relative minor starts on the 6th degree of the major scale, so it sits three half steps below the major root. The relative major of any minor key is three half steps above its root.
Shared notes means shared key signature, but the home note differs. Music that keeps returning to C sounds like C major; music that keeps returning to A sounds like A minor.
Pentatonic scales
A pentatonic scale has five notes per octave instead of seven. The two common versions are derived from the major and natural minor scales by removing the two notes that sit a half step from another scale note.
- Major pentatonic: degrees 1 2 3 5 6. In C: C D E G A.
- Minor pentatonic: degrees 1 ♭3 4 5 ♭7. In A: A C D E G.
Because the half-step clashes are gone, almost any note sounds acceptable over a matching chord. That makes pentatonics popular for melodies, riffs and improvisation. C major pentatonic and A minor pentatonic share the same five notes, just like their parent scales.
Using scales in practice
- Choose a key first, then keep melody notes mostly inside its scale.
- Notes outside the scale still work as passing tones, but they stand out, so place them deliberately.
- When a piece feels stuck, try the relative minor or major of the same notes for a different mood.
Hear it yourself
Open the Scale & Mode Explorer, pick a root and switch between major, natural minor and pentatonic. Keeping the root fixed makes the difference in step pattern easy to hear.