How do minor and major scales relate with each other?
As you might know, there are songs written in minor keys and songs written in major keys. But do you know that you can play a minor scale over a major key song and a major scale over a minor key song?
Let's first take a step back and look at how a major scale and a minor scale are build up. Whether a scale is defined as major or minor, is defined by the combination of half steps and whole steps between the notes.
A half step is the distance from one note to the next, while a whole step is the distance from one note jumping over the next one.
To give you a visual aid, here are all the 12 notes, with the notes of the C major scale marked in bold:
C C# D D# E F F# G G# A A# B C
As you can see, a major scale is build up by 2 whole steps, followed by a half step, followed by 3 whole steps, followed by a half step.
Here are all the 12 notes, with the notes of the C minor scale marked in bold:C C# D D# E F F# G G# A A# B C
A minor scale is build up by a whole step, followed by a half step, followed by 2 whole steps, followed by a half step, followed by 2 whole steps.
The relation of minor and major scales:
For every major scale, there is a minor scale that contains the exact same notes in it. But how does it work?
Let's have a closer look at the C major scheme from above, by expanding it:
C C# D D# E F F# G G# A A# B C C# D D# E F F# G G# A A# B
What you can see here, is that I've written the C major scale two times in a row. If there is a minor scale that contains the same notes, it has to be starting on one of the notes of the C major scale.
We already discussed that a minor scale has the following order:
Whole step, half step, 2 whole steps, half step, 2 whole steps.
If we are trying to lay that minor scheme above the notes of C major, we will find that it fits perfectly on the starting note 'A':
A A# B C C# D D# E F F# G G# A
That means that the A minor scale and the C major scale contain exactly the same notes and both of the keys have the same chords in them. So, if you are playing a piece in C major you can play the A minor scale over it and when you have a piece in A minor you can play the C major scale over it.
As you can see, the A minor scale starts from 3 half steps below the C major scale, so here is a general rule:
If you are in a major scale, the relative minor scale starts from 3 half steps below the major scale and vice versa.
So why do we bother at all with making a distinction between minor and major keys and don't just call all songs in A minor C major songs?
The reason why we make a separation between minor or major keys, is that they create a different feeling and that the key refers to the 'root chord' (The chord that is used at the foundation of the piece). So if you have a song in the key of A minor, you would emphasize and resolve the song to an A minor chord and if you are in C major, you would emphazise and resolve the song to a C major chord.
How to play the minor and major scale on guitar:
Here are the standard minor and major scale shapes you would use for improvisations on guitar, in case you are not already familiar with them.
Here is the minor scale shape:
and here is the major scale shape:
You would start both, minor and major scale from the root note of the key. So if you are in A minor, you would start the minor scale shape from the 5th fret of the low E-String (which is the note A) and if you are in A major, you would start the major scale shape from the 5th fret.
Since we have already discussed that the minor scale is always 3 frets lower to it's relative major scale, we know that the major scale must start 3 frets higher than the minor scale. So if we are in A minor on the 5th , we can also play the C major scale shape on the 8th fret (which is 3 frets or half steps higher).
The same goes with other keys, for example if you are in D major, with the major scale starting on the 10th fret, you can also play the B minor scale, which is starting 3 frets lower on the 7th fret.
I hope you found this article helpful, my name is Marco von Baumbach and I'm a guitar teacher from Germany. Please check out my online presence Gitarrenunterricht in Wuppertal