whole tone scale
The two whole tone scales. All 12 notes in the octave are contained in these two scales.
A whole tone scale, as the name implies, is a scale in which all the successive notes are a whole tone apart. For example, the whole tone scale starting on G is: C D E F♯ G♯ A♯. The E whole tone scale is: E F♯ G♯ A♯ C D. Notice that these two scales are made from exactly the same notes. In fact there are only two distinct whole note scales in 12-tone equal temperament, namely those starting on C and D♭. Every other whole tone scale uses one or the other of the set of notes in these two scales. The starting note gives the name of the scale.
The whole tone scale is known as a symmetric scale because it divides the octave into equal parts – six of them in this case. It's also said to be an inversionally symmetrical scale because intervals between scale degrees are symmetrical if read from the "top" (high end) or "bottom" (low end) of the scale.
Although a particular whole tone scale has a starting note, it has no tonal center and thus has a floating quality when played. It can be a useful compositional device because it allows harmonic transitions that are not possible with conventional diatonic harmony.