Scales
A scale is a collection of several pitches presented in either ascending or descending order. In this section we will look at the major, minor, and chromatic scales, which are the most common scales in Western music. We will also cover the whole-tone, octatonic, and pentatonic scales which play smaller, but important roles in Western music.
Diatonic Scales: Major and Minor
The major and minor scales are used in the vast majority of Western music written since the 17th century. These scales are considered diatonic, as opposed to chromatic (see below), as are melodies and harmonies that use the collection of pitches available in a major or minor scale.
Both major and minor scales use seven discreet pitches in a specific pattern of whole and half steps. To modern listeners, the major scale communicates a mood of happiness, triumph, joy, or contentment, whereas the minor scale can sound sad, sinister, and restless. The reason that these scales sound so different is surprisingly simple: the whole and half steps are in a different order.
Major Scale
As we consider the major scale, our primary example will be the C major scale, which uses only the white keys of the piano. Looking at the piano keys to the right, you will see that the pattern of whole and half steps going up from C to C (left to right) is Whole - Whole - half - Whole - Whole - Whole - half. This pattern is the same in all major scales.
Scale Degrees
Before we consider minor scales, we must establish some new terminology that is necessary for comparing the major and minor scales. A scale degree is a number or name unique to each note in a scale. Note names (letter names such as C and F-sharp) are different from scale degrees because a C may be the 3rd scale degree in one scale, but the 1st scale degree in another. The most important scale degrees to remember are tonic (1st [and 8th]), dominant (5th), and leading tone (7th).
| Scale Degree Number: | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 (1) |
| Scale Degree Name: | Tonic | Supertonic | Mediant | Subdominant | Dominant | Submediant | Leading Tone | Tonic |
Since scale degrees 1 and 8 are the same note name and scale degree name, we will use 'tonic' to refer to these equally from here on. These numbers and names apply to both major and minor scales with one exception: scale degree 7. See below for more details on this.
Minor Scale
Unlike the major scale, there are several different versions of the minor scale: natural (or modal) minor, harmonic minor, and melodic minor. The most essential form of the minor scale is the natural minor, so we will focus on that version.
The natural minor scale uses the same pattern of whole and half steps as the major scale, but begins in a different place in the sequence. To put it another way, if you play a major scale, but begin and end on the 6th scale degree, you will in fact be playing a natural minor scale. Our primary example of a minor scale will be the A minor scale, which, like the C major scale, uses only white keys on the piano.
| Major Scale: | W | W | h | W | W | W | h | |||||
| Natural Minor Scale: | W | h | W | W | h | W | W | |||||
Since scale degree 7 is a whole step below the tonic note, it is called the subtonic. When it is raised by a half step so that it is only a half step below the tonic (which happens very often), then it is called the leading tone just as scale degree 7 of a major scale is a leading tone.
Relative and Parallel Scales
The C major and A minor scales share the same collection of pitches. They are therefore considered to be relative scales. For example:
| C major: | C | D | E | F | G | A | B | C | |||||
| A natural minor: | A | B | C | D | E | F | G | A | |||||
| B-flat major: | B-flat | C | D | E-flat | F | G | A | B-flat | |||||
| G natural minor: | G | A | B-flat | C | D | E-flat | F | G | |||||
But there is another way that scales can be related to each other. Major and minor scales are considered parallel if they share the same tonic. In these cases, the two scales will not share the same collection of pitches: the 3rd, 6th, and 7th scale degrees will differ. For example:
| Scale Degree: | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 1 |
| C major: | C | D | E | F | G | A | B | C |
| C natural minor: | C | D | E-flat | F | G | A-flat | B-flat | C |
| Scale Degree: | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 1 |
| B-flat major: | B-flat | C | D | E-flat | F | G | A | B-flat |
| B-flat natural minor: | B-flat | C | D-flat | B-flat | F | G-flat | A-flat | B-flat |
Transposition
Transposition occurs when a segment of music is raised or lowered by a given interval, keeping all the internal intervals the same. To put it another way, when the pattern of whole and half steps of the C major scale is preserved, but we begin on C-sharp instead of C, we have transposed the C major scale into a C-sharp major scale. There are 12 possible transpositions of the major and minor scales because there are 12 discreet pitches in the Western system. Here are all 12 major scales:
Here are all 12 natural minor scales:
These scales form the basis for the system of keys which we will discuss in a later section.
Chromatic Scale
The 12 discreet pitches within an octave are C, C-sharp/D-flat, D, D-sharp/E-flat, E, F, F-sharp/G-flat, G, G-sharp/A-flat, A, A-sharp/B-flat, and B. That pattern is the chromatic scale, and it is created by simply ascending (or descending) by half-steps and thus playing all possible pitches.
Since the pattern and collection of notes are the same no matter which is the starting pitch, the chromatic scale cannot be transposed. There is only one chromatic scale.
Using the chromatic scale can make a piece sound exotic and give melodies the impression of being sinuous or elusive. Melodies of this kind are themselves called chromatic. Furthermore, any melodies and harmonies that use pitches that cannot be contained by a single diatonic (major or minor) scale are often considered chromatic as well.
In the example of the chromatic scale below, notice that it is notated using sharps when it is ascending, but when it is descending the sharped notes are replaced with their enharmonic equivalents so that only flats are used. This is a common convention for notating chromatic scales.
Other Scales
Whole-Tone
Just as the chromatic scale is built using only half steps, the whole-tone scale uses only whole steps. Because the distance between each successive pair of notes is the same, there is no way for the listener to know which note is the tonic. This makes the whole-tone scale tonally ambiguous. The same is true of the chromatic scale.
There are only two possible collections of notes that can be used to create whole tone scales. Any further transpositions will only duplicate one of these collections. For our purposes, we will call these the C and C-sharp whole-tone scales.
The tonal ambiguity of the whole-tone scale makes it appealing to composers who wish to avoid traditional tonality or who want to communicate the idea of disorientation or vagueness.
Octatonic
The octatonic scale is a combination between the principles behind the chromatic scale and the whole-tone scale in that it alternates between whole and half steps. In the examples below, the scale begins with a half step, but beginning with a whole step is also acceptable. Whichever interval comes first, there are only three collections of pitches that can be used to create octatonic scales. Like the whole-tone scale, any transpositions beyond these will only duplicate an existing collection.
Pentatonic
The word 'pentatonic' can refer to any scale or system of music that uses only five pitches, but is generally understood to indicate the scale pattern shown here, which is by far the most common five-note scale. The pattern is made up of whole steps and minor thirds (between E and G as well as A and C, in this case).
To the Western ear this scale often seems exotic, but it functions more similarly to major and minor scales than the whole-tone or octatonic scales. In the video below Bobby McFerrin demonstrates the universality of the pentatonic scale.
For more fun with the pentatonic scale, see ToneMatrix, a beautiful flash app that allows you to compose using the pentatonic scale.