A diatonic scale is either a major or minor scale, containing 8 notes counting the tonic twice (top and bottom). The degrees of the diatonic scale can be numbered or named in several ways, described here. The diatonic scale is contrasted with the chromatic scale in which all intervals are semi-tones, and which has 13 notes. You may choose major, harmonic minor, melodic minor, or chromatic scales by clicking one of the 4 option buttons at top left.
Major scales have a bright , lively sound, and have been used more than any other type of scale since around 1600. The interval between the tonic and the 3rd note of the scale (mediant) is a major third, and the interval between the tonic and the sixth note of the scale is a major sixth. The notes in the scale may be identified by numbers from 1 to 7, often written as roman numerals I to VII, or by formal names 1=Tonic, 2=super-tonic,3= mediant, 4=sub-dominant, 5=dominant, 6=sub-mediant, 7=leading note.
Minor scales have a sadder sound. The mediant is a minor third above the tonic, and the sub-mediant is a minor sixth above the tonic. Each minor scale starts on a note one minor third below the tonic of the major scale with the same key signature. This major scale is called the relative major. The minor scale may be used in its natural state, that is, using exactly the same notes as the relative major, but starting 3 notes lower. However, more often it is used in one of two other forms, the harmonic minor and the melodic minor. You may select melodic or harmonic minor scales instead of major from the option buttons on the top left panel.