Changes

Remember that F is a fifth below C and G is a fifth above. We notice that if we change the key by moving in the root note by perfect fifths, only one note changes. While no two major scales will have different tonic notes but identical sets of notes, some scales are more ''inter-related'' or harmonic than others.

The circle of fifths lists keys in 5ths, which is useful to determine how interrelated any two keys are. The points opposite each other (12 vs. 6, 3 vs. 9, 11 vs. 5, etc.) are the least related, while the points nearest each other (12 and 1, 1 and 2, etc.) are most related. As we go right or clockwise, we sharp the 4th of the current key to get the next key. For example in C Major, sharping the 4th (F) gives us the scale of G Major. As we move left or counter-clockwise, we flatten the 7th of the current key to get the next key. For C Major, we flat the B to get F Major.

The full circle only consists So each movement is a single note difference, always adjusting the leading tone of the 12 tones, which can be arranged like key on the clockwise side of the hours on an analog clockpair. The points opposite each other (12 vs. 6, 3 vs. 9, 11 vs. 5, etc.) are Note that the least relatedmajor scale has two half-steps, while the points nearest which means two notes right next to each other (12 and 1, 1 and 2, etc.) are most related. As we go right Every other major or clockwisenatural minor scale has to contain at least one of these notes, we sharp since the 4th of largest movement between neighboring notes is a whole step. So the current key to get the next keyleast related scales will share 2 notes. For example , C and C{{s}} don't share any notes by name - every note in C Major, sharping is the 4th (F) gives us the scale of G Major. As we left or counter-clockwise, we flatten the 7th of the current key to get the next keysame note in C{{s}} but sharped. For C MajorHowever, we flat the E{{s}} = F and B to get F Major{{s}} = C; so they still have two notes in common.

So each movement is a single note difference. Note that the major scale has two half-steps, which means two notes right next to each other. Every other major or natural minor scale has to contain at least one of these notes, since the largest movement between neighboring notes is a whole step. So the least related scales will share 2 notes. For example, C and C{{stop}} don't share any notes by name - every note in C is the same note in C{{s}} but sharped. However, E{{s}} = F and B{{s}} = C; so they still have two notes in common.