## Structure of a Scale

The standard tuning system with which most people are familiar (the one that is used on any piano) is known as equal temperament. According to this system of tuning, the distance between octaves is equally divided into twelve consecutive notes. The technical definition of a scale is simply a series of notes selected from these twelve, so theoretically there is an infinite number of possible scales.

Each one of the notes from a scale is known as a degree; each degree of a scale has its own name but is often refered to by a Roman Numeral. For example, the standard major scale consists of the degrees: I, II, III, IV, V, VI, and VII. These labels are merely used to define the relationship between the notes of a scale; as such, the eighth note of a major scale is refered to as degree I since the eighth note is the same as the first, apart from the fact that it is an octave higher.

Any two scales can be distinguished by two things:

1. The number of notes that they have in them (i.e. the number of degrees they have)
2. The distance between their degrees

For example, you can build seven different scales using just the seven natural notes (the white keys on a keyboard), all you need to do is change the note that you start on for each scale. Since there are seven different natural notes, there are seven different possible starting points, hence seven different possible scales. The major scale has semitones separating degrees III-IV and VII-I (remember that the eighth note of a major scale is refered to as I).

## Relative Scales

Relative scales are two different scales that share the same notes. For example, the major scale of C and the minor scale of A contain the same notes. They are both relative scales: C is the relative major of A, and A is the relative minor of C. The relative minor of a major scale is the same as the degree VI of the major scale, and the relative major of a minor scale is the same as the degree III of the minor scale.

## More about the Minor Scale

You may not like to hear this, but there are (in fact) three different types of minor scale. All three have different degrees VI and VII:

1. Natural minor: this is the one we’ve already looked at, and it consists of the same notes as its relative major. Hence the name natural.
2. Harmonic minor: degree VII is raised to form an augmented second between Degrees VI and VII. It also puts a distance of a semi-tone between degrees VII-I. This forms a dominant chord or dominant 7th chord on the fifth degree of the scale (these new terms are explained below).
3. Melodic minor: degree VI is raised along with degree VII to avoid the augmented second formed in the harmonic minor.

## Other Names for Scale Degrees

These are the names of the degrees mentioned earlier:

Degrees and their Names

Degree Name
I Tonic
II Supertonic
III Mediant
IV Subdominant
V Dominant
VI Submediant