What Is a Diatonic Scale?
A diatonic scale is a type of musical scale that contains seven tones of a note per octave (the distance between one note and the following note that also bears its name).
Diatonic scales consist of five whole tones, also known as whole steps or the major second, and two half steps (semitones), which are the shortest musical intervals (the distance between tones) in Western music, separated by either two or three tones. A whole step on a piano keyboard represents two keys, while a half step is a single key.
Also known as a heptatonic scale in music theory, diatonic scales use all seven letter names, or notes in a sequence. Chords built from the seven notes in each key are called diatonic chords. Tonality, or the system of organizing keys and chords in Western music, has been based on the diatonic system from the Middle Ages to the present day.
Diatonic scales include both the major scale, or Ionian mode, which is the most frequently used musical scale, and the natural minor scale, or Aeolian mode, which uses the same number of notes as the major scale, but in a different pitch. Both scales are part of the six “church mode” scales established for religious music during the medieval period, which continue to form the basis for contemporary diatonic scales.
Tonic - the root note
These scales always have a tonal center to which all the notes relate and lead to in different ways. It is called the root note of the scale or tonic.