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 are no aural cues that let the listener 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.
whole-tone scale on C
whole-tone scale on C-sharp
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.
The octatonic scale alternates between whole and half steps, and is therefore a combination of the principles behind the chromatic scale and the whole-tone scale. In the examples below, the scale begins with a half step, but beginning with a whole step is also possible. 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 further transpositions will only duplicate an existing collection.
the three transpositions of the octatonic scale
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 (major seconds) and minor thirds (between E and G as well as A and C, in this case).
the (common) pentatonic scale
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.
World Science Festival 2009: Bobby McFerrin Demonstrates the Power of the Pentatonic Scale
For more fun with the pentatonic scale, check out ToneMatrix, a beautiful flash app that allows you to compose using the pentatonic scale.