Introduction to note intervals
To understand how the notes which make up a music scale is derived, the intervals between notes in Western music must be known. The intervals between the notes are either a full tone (T) or a semi-tone (H). The notes in an octave are: C, C#/D♭, D, D#/E♭, E, F, F#/G♭, G, G#/A♭, A, A#/B♭, B, C. These notes correspond to each key on a piano. Between a note and the next in the series is a semi-tone. Two semi-tones equal a full tone. So between E and F is a semi-tone and between E and F# is a full tone.
Deriving a major scale
The major scales follow the pattern:
T T S T T T S
where T stands for a full tone and S stands for a semi-tone.
So if we were to derive the D major scale, we would first start with the tonic (the first note of the scale) which will be D, then following the pattern, the first interval is a tone so the next note will be the one which is a full tone after D which is E. The second interval is again a tone and the note that is a full tone ahead of E is F#. The third interval is a semi-tone so this time the next note is G. After that, following the pattern we get the remaining notes in the D major scale which are A, B, C#, D. So D major is composed of D, E, F#, G, A, B, C#, D. The other major scales are derived using the same pattern but with a different starting note.
A major
A♭ major
B major
B♭ major
C major
D major
D♭ major
E major
E♭ major
F major
G major
G♭ major
