And that is the 'natural' minor; not the harmonic minor...right? And is there a simple rule to knowing the scales of a minor key? I know you take the 3rd note down a half step. is it a rule to take the 6th and 7th down a half step also. I am getting a little confused. I'm not even sure why I need to know this. But I imagine it is VERY useful down the road somewhere. Thanks
It refers to any minor: natural, melodic, or harmonic since it only gives the tonic.
To your question: Yes, a minor scale will have a lowered third note - C major starts C D E F G... (and you end up with a major chord C E G) while C minor starts C D Eb F G .... (and you end up with a minor chord (C Eb G) - but it's hard to remember the rest of the notes that way. This is where the circle of fifths comes in.
The scale that has the same key signature but starts 3 notes down (or 6 notes up = the same note) will be the relative minor scale. So: 3 flats gives us Eb major:
2F 3G 4Ab 5Bb 6C
7D Eb ..... If you start 3 notes lower you get C minor:
1C 2D 3Eb
4F 5G 6Ab 7Bb C
So C natural minor is the relative minor of Eb major. They share the same key signature and the same notes, except that C minor starts on the 6th note of the Eb major scale.
You can turn C natural minor into C harmonic minor by raising the 7th note (leading note) by a half tone. Bb becomes B. That brings it right next to the C making us feel the tonic more. It also allows for chords that are stronger in harmony.
So your natural minor
C D Eb F G Ab 7Bb
as harmonic minor
C D Eb F G Ab 7B
This has an "oriental" sound, and there is also a big leap of 3 half notes between Ab and B, so the melodic minor got invented. You have the same notes as harmonic minor, but this time you also raise the 6th note:
Eb F G Ab Bb C D Eb
C Natural minor
---- C D Eb F G Ab Bb
C Harmonic minor
---- C D Eb F G Ab B (natural)
C Melodic minor
---- C D Eb F G A (natural)
So this is the way to get minor scales by looking at the relative major scale that has the same key signature. If you start with the natural minor, then you can figure out the harmonic and melodic minor from there. If you want to remember what the intervals are between the notes, you can discover them by using this as your starting point. The easiest is probably A natural minor, since it's like C major that starts and ends on A with no black notes.
Anyway, that's what the circle of fifths is describing with the lower case scale names beside the upper case ones.