Most all music that we know or hear is tonal - the melodies and harmonies are centered around a main note, or pitch, called a tonic. Scales are series of consecutive notes, ascending or descending, that are built on the tonic.
For example, here is a scale built on the note C.
C is the tonic. This particular scale is a major scale.
The major scale is one of the most common scales in music. It is the basis of the song "Do-Re-Mi" from The Sound of Music.
Go here for a full discussion of MAJOR SCALES.
Listening to music can evoke several emotional qualities - the two most common might be "happy" or "sad".
A "bright" or "happy" feeling is usually associated with songs in major keys - built on a major scale. A very large portion of music of all types and styles is build on major scales.
An equally large portion of music is built on minor scales. This music might be considered "somber or "dark"
There are three versions of the minor scale
The essential mood and characteristic of the major and minor qualities is determined by only one note: the 3rd of the scale.
The major scale has a major 3rd while all minor scales have a minor 3rd. The small difference between these two intervals results in a profound, powerful emotional change of mood.
Go here for a full discussion of MINOR SCALES.
Chromatic Scales are series of 12 consecutive notes, each a half step (or semitone) apart. So on the piano keyboard it uses all of the white and black keys of the musical alphabet.
For some amazing chromatics and chromatic scale playing, look at this video of a piano version of the "Flight of the Bumblebee." It's a transcription of an orchestral interlude written by Nikolai Rimsky-Korsakov for his opera The Tale of Tsar Saltan, composed in 1899–1900.
Go here for a full discussion of CHROMATIC SCALES.
The blues scale is fun to play. It resembles a minor pentatonic scale and to a lesser extent, a narural minor sale.
It's a 7 note scale that has a:
root - flat 3rd - 4th - flat 5th - 5th - flat 7th - root.
It is unique because the "blue notes of the scale (flat 3rd & flat 5th) technically clash with the standard chords that are used in a 12 bar blues progression.
The chords in a blues progression are usually all 7th chords - in the key of C they would be C7 - F7 - G7.
The flat 3rd and flat 5th technically clash with the 3rds and 5ths in the chord progressions, but that's the unique thing about the sound of the Blues and the blues scale.
Go here for a full discussion of The BLUES SCALE
The pentatonic scale is arguably one of the most widely used scales in music - it's easy to play and easy to improvise on.
If you have ever played around with or tried improvising with just the black keys on a piano, you have been playing with a Gb major pentatonic: Gb-Ab-Bb-Db-Eb
Bobby McFerrin demonstrates the power of the pentatonic scale, using audience participation, at the event "Notes & Neurons: In Search of the Common Chorus", from the 2009 World Science Festival, June 12, 2009.
Go here for a full discussion of The PENTATONIC SCALE
Follow these links for a more complete presentation of these scales.