In music, a whole tone scale is a scale in which each note is separated from the next one by an interval of a whole tone. There is always one note (a semitone) in between each neighbouring pair of notes of the whole-tone scale. Whatever note is started on, the whole tone scale will contain one of the following sets of notes:
- C, D, E, F#, G#, A#
- C#, D#, F, G, A, B
When a whole-tone scale is played on a piano, starting from a low note and moving up to high notes, while at the same time pressing the sustaining pedal (the right pedal), it makes a "dreamy" sound. It does not sound in any particular key, but floats along. It also sounds very good on a harp.
Debussy uses the whole-tone scale a lot in his music, but he was not the first to do so. Russian composers such as Glinka in his opera Ruslan and Ludmila and Borodin in Prince Igor used the whole-tone scale.