The structure in steps
A major scale follows the pattern whole – whole – half – whole – whole – whole – half. C major looks like this: C D E F G A B C.
The natural minor scale follows whole – half – whole – whole – half – whole – whole. A minor is: A B C D E F G A.
The third makes the difference
The biggest difference lies in the third note, the third. In major it sits four semitones above the root (major third), in minor three (minor third). That's why major often sounds bright and minor darker or more melancholic.
The sixth and seventh notes also sit a semitone lower in natural minor than in major.
Relative keys
C major and A minor use exactly the same seven notes. We call A minor the relative minor of C major. You always find the relative minor three semitones below the major root.
The difference is which note feels like 'home': in C major, melodies like to end on C, in A minor on A.
Practice tip
On the fretboard map, select C major and then A minor. The notes stay the same, only the orange root note shifts. Play the scale from both roots and listen to the difference.
Read also

Guitar Fretboard Notes
How the twelve notes are laid out across the strings and frets.

Pentatonic Scale Guitar
Five notes that let you start soloing straight away.

Soloing over the 12-bar blues
The most famous chord progression in the blues, and how to solo over it.

Pentatonic licks that always work
Four classic licks in A minor, with tab.

