Harmonic and melodic minor
Raise the seventh and sixth degrees to get the harmonic and melodic minor, and hear how they differ.
The harmonic minor
In the natural minor, degree VII is a whole tone below the tonic and does not lean towards it. To make minor sound more settled, degree VII is raised a semitone: in A minor G becomes G♯. This is the harmonic minor.
Now degree VII is a semitone below the tonic, as in major, and leads to it. The raised degree is written with an accidental in the music; it is not in the key signature.
The harmonic minor scale on A: G♯ instead of G
A harmonic minor on the keyboard
Between degree VI and the raised VII there is a wide step of a tone and a half (F–G♯). It gives the harmonic minor its familiar exotic colour.
Practice: What the harmonic minor raises
Practice: The wide step
The melodic minor
To smooth out that wide step, degree VI is raised too: F → F♯. This is the melodic minor: going up it has raised VI and VII; coming down it is the natural minor, with nothing raised.
Melodic minor going up: F♯ and G♯
Coming down: the natural minor, G and F