Major & Minor Modes
Here's a C major scale. I've left marks at each half-step, but only labeled the notes that are actually in our scale:
C D E F G A B C +--+--+--+--+--+--+--+--+--+--+--+--+
7 Modes Derived from a Major Scale
We can get different "modes" by starting the scale in different places.
Music based on these different modes have a different "feel", or character.
C D E F G A B C (Ionian) +--+--+--+--+--+--+--+--+--+--+--+--+
D E F G A B C D (Dorian)
+--+--+--+--+--+--+--+--+--+--+--+--+
E F G A B C D E (Phrygian)
+--+--+--+--+--+--+--+--+--+--+--+--+
F G A B C D E F (Lydian)
+--+--+--+--+--+--+--+--+--+--+--+--+
G A B C D E F G (Mixolydian)
+--+--+--+--+--+--+--+--+--+--+--+--+
A B C D E F G A (Aeolian)
+--+--+--+--+--+--+--+--+--+--+--+--+
B C D E F G A B (Locrian)
+--+--+--+--+--+--+--+--+--+--+--+--+
Aligned to the same start
Let's repeat this, shifting them all back to the same starting point:
C D E F G A B C (Ionian) +--+--+--+--+--+--+--+--+--+--+--+--+
D E F G A B C D (Dorian) +--+--+--+--+--+--+--+--+--+--+--+--+
E F G A B C D E (Phrygian) +--+--+--+--+--+--+--+--+--+--+--+--+
F G A B C D E F (Lydian) +--+--+--+--+--+--+--+--+--+--+--+--+
G A B C D E F G (Mixolydian) +--+--+--+--+--+--+--+--+--+--+--+--+
A B C D E F G A (Aeolian) +--+--+--+--+--+--+--+--+--+--+--+--+
B C D E F G A B (Locrian) +--+--+--+--+--+--+--+--+--+--+--+--+
With numbers!
What's important is the relative pitches, not where we actually start. Music in each mode could be rooted on any note, so let's rewrite these with numbers.
As is common, I'm using unaltered numbers for the common (major) scale and adjusting those up or down with a "#" or "b".
1 2 3 4 5 6 7 1 (Ionian) +--+--+--+--+--+--+--+--+--+--+--+--+
1 2 3b 4 5 6 7b 1 (Dorian) +--+--+--+--+--+--+--+--+--+--+--+--+
1 2b 3b 4 5 6b 7b 1 (Phrygian) +--+--+--+--+--+--+--+--+--+--+--+--+
1 2 3 4# 5 6 7 1 (Lydian) +--+--+--+--+--+--+--+--+--+--+--+--+
1 2 3 4 5 6 7b 1 (Mixolydian) +--+--+--+--+--+--+--+--+--+--+--+--+
1 2 3b 4 5 6b 7b 1 (Aeolian) +--+--+--+--+--+--+--+--+--+--+--+--+
1 2b 3b 4 5b 6b 7b 1 (Locrian) +--+--+--+--+--+--+--+--+--+--+--+--+
Major/Minor Modes
Now I'll also group these into the major and minor modes. The 3rd and 5th nodes of the scale are special. Only Locrian has a different 5th than the others, so that's very special. So for most of these it's not the 5th that guides our grouping, but the 3rd:
Modes with a major 3rd are "major", and modes with a minor(/flat/lowered) 3rd are minor:
Major modes:
1 2 3 4 5 6 7 1 (Ionian) +--+--+--+--+--+--+--+--+--+--+--+--+
1 2 3 4# 5 6 7 1 (Lydian) +--+--+--+--+--+--+--+--+--+--+--+--+
1 2 3 4 5 6 7b 1 (Mixolydian) +--+--+--+--+--+--+--+--+--+--+--+--+
Minor modes:
1 2 3b 4 5 6 7b 1 (Dorian) +--+--+--+--+--+--+--+--+--+--+--+--+
1 2b 3b 4 5 6b 7b 1 (Phrygian) +--+--+--+--+--+--+--+--+--+--+--+--+
1 2 3b 4 5 6b 7b 1 (Aeolian) +--+--+--+--+--+--+--+--+--+--+--+--+
And Locrian, which has a minor 3rd, but also that lowered 5th, so I'll put it by itself:
1 2b 3b 4 5b 6b 7b 1 (Locrian) +--+--+--+--+--+--+--+--+--+--+--+--+
No need to remember!
Alright, this section is why I wrote the post. I was excited when I realized I don't need to memorize which modes are major vs minor.
I still have trouble remembering the names (except Dorian and Aolian, since we can get them by starting on D and A respectively... and "Locutus of the Borg" makes me think of Locrian with its disturbing lowered 5th).
But I no longer have trouble remembering where in a C major scale the major or minor modes would start. The key is where are the half steps. I'll mark those here with "!!":
C D E F G A B C +--+--+--+--+!!+--+--+--+--+--+--+!!+
Where would we start to get Locrian, our mode with a lowered 5th (three whole steps and two half steps)? We've only got two half steps, so it's very hard to travel 5 notes in the scale and pick up both of them. In fact, there's only one way to do it: We can start on B right before one of the half steps, and just barely pick up the other one. That's Locrian! Starting anywhere else, we'd have 4 whole steps and 1 half steps between our "1" and "5".
For the rest:
- major: two whole steps between the "1" and the "3"
- minor: one whole step and one half step between the "1" and the (flat) "3"
Starting on C, we get our two whole steps for a major 3rd. Where else can we start? The only other place with multiple whole steps in a row is "F G A". Starting on either F or G gives two whole steps.