The Major Scale

Lesson 25 details the origins of the Western scale.

This lesson concentrates on what a major scale is, and how starting from any of the twelve notes in the chromatic scale one derives the twelve major scales.

Examine the keyboard again. Starting from the key marked middle C (that is, the key C with an asterisk), play the naturals (i.e. the white keys) in ascending order, C, D, E, F, G, A, B and finish on the C above middle C. This sequence or row of eight notes is the C major scale, the major scale for which the key-note is C. Music written using the notes of this scale is said to be ' in the key of C '. The different notes are called the degrees of the scale such that the key note, C, is called the 'first degree of the scale', D is the 'second degree of the scale', and so on.

The eight degrees of the scale may be numbered using 1 - 8 or Roman numerals I - VIII (i.e. I, II, III, IV, V, VI, VII, VIII) or i - viii (i.e. i, ii, iii, iv, v, vi, vii, viii).

What makes this a major scale is the distinctive sequence of tones (whole steps) and semitones (half steps). If we write down the intervals between the notes rather than the note names then the C major scale becomes tone-tone-semitone-tone-tone-tone-semitone, seven intervals between eight notes.

If you play any other ascending row of eight consecutive naturals you will find many different sequences of intervals. C major is the only major scale, that is a scale obeying the interval sequence tone-tone-semitone-tone-tone-tone-semitone, using only the white keys.

In 'whole step-half step' notation this sequence is written whole step - whole step - half step - whole step - whole step - whole step - half step.

The Tetrachord

There is another way of looking at the major scale. It is derived from a pattern of four notes called the tetrachord (Greek: tetra = four, chorde = string or note: originally from tetrachordon, an ancient Greek four-stringed instrument). The ancient Greeks applied the term originally to a falling sequence of four notes with a number of patterns including the interval pattern tone - tone - semitone. Today, we use the term to mean a rising sequence of four notes including that using the interval pattern tone - tone - semitone. The word tetrachord can be applied to the interval, a perfect fourth, between the first and last note of the four note sequence as well as to all the notes in the sequence itself.

The C major scale is in fact two tetrachords, one after the other, separated by a tone, in which case the two tetrachords are said to be combined by disjunction.

Thus:

C - tone - D - tone - E - semitone - F : the first tetrachord
G - tone - A - tone - B - semitone - C : the second tetrachord

The interval between F, the last note of the first tetrachord, and G, the first note of the second tetrachord, is a tone.

If we start on G, to produce the G major scale, the pattern will be

G - tone - A - tone - B - semitone - C : the first tetrachord
D - tone - E - tone - F# - semitone - G : the second tetrachord

The interval between C, the last note of the first tetrachord, and D, the first note of the second tetrachord, is a tone and so again the two tetrachords are said to be combined by disjunction.

The Twelve Major Scales

We return to the chromatic scale starting on middle C which has been written twice: on the upper line with only naturals and flats and on the lower line with only naturals and sharps. Both scales 'play' the same row of notes.

Deriving Major Scales

Using the distinctive major scale interval sequence, tone-tone-semitone-tone-tone-tone-semitone we can construct each of the scales in turn.

We have provided two 'worked examples' below.

Let us examine first one of the 'sharp' scales, the ' A major scale '.

Notice that we have used C sharp rather than D flat to avoid using D twice in the scale. Similarly F sharp and G sharp must be chosen in preference to their enharmonic names G flat and A flat.

We have laid out the A major scale on the treble clef below, the upper line showing the notes themselves, missing only superfluous natural signs, and the lower line showing how, by using a key signature, (the three sharps displayed on the left hand side of the stave), the sharp signs are 'understood' and need not be displayed again within the score. You will notice that the three sharp signs in the key signature mirror the three sharps in the scale on the upper line.

And now, let us derive one of the 'flat' scales, the ' E flat major scale '.

Again we have chosen flat names rather than their enharmonic sharp names to satisfy the requirement than all note letter names be different.

We have laid out the E flat major scale on the treble clef below, the upper line showing the notes themselves, missing only superfluous natural signs, and the lower line showing how, by using a key signature, (the three flats displayed on the left hand side of the stave), the flat signs are 'understood' and need not be displayed again within the score.

Chart of the Major Scale

In the next lesson we will examine the way key signatures are used and the 'conventions' associated with the use of 'natural', 'sharp' and 'flat' signs.