Minor
Minor is the darker, sadder-sounding mode. A natural minor scale follows the pattern whole, half, whole, whole, half, whole, whole, and a minor triad has a minor third (three half steps) at the bottom.
The simplest minor scale is A minor: the same white keys as C major, but from A to A. The half steps still fall between B and C and between E and F, yet in the scale they land in other places – after the second note and after the fifth. That is why minor sounds different.
C major and A minor share a key signature – no sharps or flats – and differ only in their tonic. Keys like these are called relative keys. The relative minor starts on the sixth degree of the major scale: for G major it is E minor, for F major D minor. The textbook teaches the natural minor; in the harmonic minor the seventh degree is raised a half step (G♯ in A minor).
The minor triad A–C–E: from A to C is three half steps, a minor third; from C to E four, a major third. The minor third at the bottom makes the triad minor: its middle note is one key lower than in a major triad.
What it sounds like
Minor sounds darker and sadder than major – thoughtful, sometimes dramatic. The difference comes down to one half step: the third above the tonic.
Where it is taught: the studio’s interactive textbook, chapter 8, “Minor: A minor and relative keys” and chapter 9, “Triads: C, F, G”.