Piano Power: Diatonic Scales
The two most popular diatonic scales used in Western music are the Major and Minor scales. In this article, we'll discuss major scales, their construction and how they relate to each other. Before we go any further though, please read the following definitions:
* Diatonic scale: a scale consisting of whole steps and half steps.
* Interval: the distance between and including any two notes.
* Half Step: the smallest interval on the piano. (e.g.. C-C#, E-F, B-C, Bb-B, etc...)
* Whole Step: the interval formed by combining two half steps. (e.g.. C-D, Eb-F, E-F#, Bb-C, etc...)
Now let's take a look at the definition of a major scale.
A major scale is a series of eight consecutive notes whose adjacent pairs of notes are all whole steps, except for the intervals formed by steps 3-4, 7-8 which are half steps. Here's an example of the C major scale:
Looking at C Major we notice several things:
* The notes or letter names are consecutive. Each note is followed by the very next letter in the musical alphabet. (The musical alphabet consists of the first seven letters of the alphabet A,B,C,D,E,F,G).
* Half steps exist between 3-4 (E-F) and 7-8 (B-C).
* All other adjacent intervals are whole steps (C-D, D-E, F-G, G-A, A-B).
* There are no accidentals (sharps or flats). Therefore, if played on the piano, all of the notes are white keys.
We now have a model for constructing the next major scale, G Major. We begin with eight consecutive notes beginning with G, the 5th note of C major.
Upon closer scrutiny we note that there's a problem. All of the conditions (whole and half steps) are met for steps 1-6. However, interval 6-7 (E-F) is a half step and should be a whole. Additionally, interval 7-8 (F-G) is a whole step and should be a half.
Remedy: Raising the F to an F# serves the dual role of changing interval 6-7 to a whole step (E-F#) and interval 7-8 to a half step (F#-G).
Looking at G Major we notice several things:
* The root of the scale (G), is the 5th note of the C scale.
* A new sharp was added to the 7th step of the scale.
* It is the exact same set of notes as the C scale, except for the new note, F#. Therefore, we could say that G Major inherited all of the notes of C Major, except for the F#.
Let's continue by going to the 5th step (D) of the G scale and constructing a scale.
Once again, there are problems. Intervals 2-3 and 6-7 are half steps, while intervals 3-4 and 7-8 are whole steps.
Remedy: Raise F and C a half step to F# and C# respectively.
Looking at D Major we notice several things:
* The root of the scale (D), is the 5th note of the G scale.
* A new sharp (C#) was added to the 7th step of the scale. (F# is no longer considered a new sharp because it was already introduced in the G scale.)
* It is the exact same set of notes as the G scale, except for the new note, C#. Therefore, we could say that D Major inherited all of the notes of G Major, except for the C#.
Using the information above, we can predict the following for the next major scale in our cycle:
* It will begin on the 5th step of the D scale
* It will inherit all of the notes of the D scale (including the F# and C#), except for the note on the 7th step.
* The 7th step will be raised a half step thus adding a new sharp to the scale.
You now have enough information to construct the remainder of the scales that use sharps. They are
A, E, B, F#, and C# major. In our next lesson, we'll take a look at the major scales that use flats to make them sound correct.