A chromatic scale is a musical scale that consists of twelve pitches, each a half step apart. It includes all the notes in an octave, which are represented by the keys on a piano. The scale can be played ascending or descending, and it provides a complete set of notes for creating melodies and harmonies. In Western music, the chromatic scale is often used to add color and complexity to compositions. It contrasts with the diatonic scale, which contains seven notes and follows a specific pattern of whole and half steps. Musicians frequently use the chromatic scale for improvisation and to enhance their musical expression.