Types of Scales: Whole Tone and Octatonic scales

Sails

Although most of the music we commonly hear is in one or more of the diatonic modes, composers have used two or three other types of scale.  To understand these other scales, we must first consider the sizes of intervals. 

In the United States we talk about whole steps and half steps.  In practical terms, a half step--called a semitone in Great Britain--is the distance between two adjacent keys on the keyboard.  From C to C# is a half step.  So is C# to D, D to D# and D# to E.  From E to Eb, Eb to D, and D to Db are all half steps.  If there is no key in between, the interval is a half step, even if the keys are the same color, like E to F.  The interval of two half steps, like from C to D or from C# to D#, is called a whole step, a tone in Great Britain. 

Keyboard

Now we can see what the intervals are in pentatonic scales.  From DO to RE is a whole step; RE to MI is a whole step; from MI to SOL is 1 1/2 steps; and from SOL to LA is a whole step. 

In Major Scales, the most commonly used scale in Western music, the pattern is like this: DO to RE=whole; RE to MI=whole; MI to FA=half step; FA to SOL=whole; SOL to LA=whole; LA to TI=whole; TI to the higher DO=half step.  In abbreviated form, Major is WWHWWWH.  Starting on any note, using this pattern of whole and half steps, in that order, creates a major scale. 

We can create a scale using any combination of intervals. For example, we could use a scale consisting only of whole steps. It is known as a whole-tone scale.

On YouTube, listen to this dreamy scale used by Debussy (1862-1918) in “Voiles” (“Sails”). One of the recordings also shows the musical score. Notice the large number of sharps and flats. This is because our standard notation, the five line staff, is based on the diatonic scale, so a whole-tone scale doesn’t fit as neatly as a diatonic scale does. We often hear whole tone scales in TV and movie scores to accompany dream sequences.

Another scale, famously used by Bela Bartok (1881-1945) is called octatonic. It consists of alternating half-steps and whole steps. You can hear it in this 4-minute recording by going to Movement III allegro molto.

Each type of scale has its own character and personality!