Put simply, a chromatic scale involves playing all the notes (including sharps/flats) between two notes that are an octave apart.
For example, picture the keys on a piano – the heptatonic (seven-note) scale of C Major involves playing only the white keys: C, D, E, F, G, A, B, before reaching C again an octave higher. However, if you were to play a chromatic scale starting on C, you would play 12 notes before reaching C again –playing each white and black key (each semitone) in turn: C, C#, D, D#, E, F, F#, G, G#, A, A#, B.
Playing chromatic scales can be useful when learning a new instrument, as each note is practised in turn, but this type of scale is also used within pieces of music. For example, Nikolai Rimsky-Korsakov’s Flight of the Bumblebee makes use of chromatic scales, which help create the frantic feel of the piece when combined with its fast tempo.
When playing a piece of music in a particular key, any accidentals (sharps or flats not usually contained in that key) are also known as chromatic notes.
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