Major scales
Tones and semitones
A semitone is the smallest step on a piano: from one key to the very next one, black or white. A tone is two semitones, with one key in between.
Most neighbouring white keys are a tone apart. There are two pairs with no black key between them, so they are only a semitone apart: E to F and B to C.
The major scale pattern
A scale is a run of notes from one note up to the same letter an octave higher. A major scale always uses the same pattern of steps:
tone, tone, semitone, tone, tone, tone, semitone
The semitones fall between notes 3 and 4 and between notes 7 and 8. C major uses only the white keys, because E to F and B to C fall in exactly the right places.
G, D and F major
Start the pattern on another note and some steps need a sharp or a flat to keep it right:
- G major needs F sharp, so that 7 to 8 (F sharp to G) is a semitone.
- D major needs F sharp and C sharp.
- F major needs B flat, so that 3 to 4 (A to B flat) is a semitone.
A scale can be written going up (ascending) or coming down (descending): the notes are the same, in reverse order. In exam questions scales are written in semibreves, one octave, with or without a key signature.
Worked example: add the accidentals
Here are the letters of the D major scale. Which accidentals does it need?
- D to E is a tone. E to F is only a semitone, but we need a tone, so F becomes F sharp.
- F sharp to G is now a semitone, which is right for 3 to 4.
- Carry on: G, A, B are tones. B to C is a semitone, but 6 to 7 needs a tone, so C becomes C sharp; then C sharp to D is the semitone for 7 to 8.
- D major needs F sharp and C sharp.
This question is in Brainlag Plus