However, if you examine each scale individually, you will see that a scale consists of eight intervals (notations). Let us refer to them as they ascend as numerals — 1, 2, 3, 4, 5, 6, 7, 8. Let's place those numbers on a Keyboard in the scale of the Key of C:

If you were to play the notes of 1 and 5, you will hear an interval called a fifth. Further, if you were to play (or voice) an interval (or, notes) of 1 and 2 together you will hear a certain dissonance. If you were to play an interval of 1 and 3, you will hear a harmonic duo called a third. If you were to play an interval of 1 and 4, you will hear a duo called a fourth. If you were to play an interval of 1 and 5 you will hear a duo called a fifth. If you were to play an interval of 1 and 6, you will hear a duo called a sixth. If you were to play an interval of 1 and 7, you will hear a duo called a major seventh. If you were to play an interval of 1 and 8, you will be playing an octave; notice that 1 and 8 are the same notes, only the pitch is different (one sounding lower, one sounding higher to your ear).

Progression by Fifths--how it works

When examining The Music Wheel clockwise, notice that the V chord of each new slice becomes a I chord in the neighbor slice. Further, notice that the I chord in a slice shows up in the next slice as a IV chord.

For instance, examine the I, IV, V chords of the Key of C. Now examine the I, IV, V chords of the Key of G. What have you discovered?

Moving through the 12 Keys by Fifths

The most effective way I have taught the method of playing music through the 12 Keys by fifths is to direct a student to play the old “Heart ‘n Soul” chord progressions. Its pattern of chord progressions in the Key of C is I=CEG; i= ACE; IV=FAC; V=GBD. (Notice that you are using the C chord’s relative minor as your second chord. This is typical of a simple music composition to include one of its minor relatives). On a keyboard, the first three chords are played in a descending pattern. Each descending succession retains two of the preceding chord’s notes, so that only one note changes with each succession. The last chord ascends by one step. That chord is the V=GBD chord. That V chord now shows up as the I chord of the next slice.

Key of G: Now you can begin to play “Heart ‘n Soul” progressions through the Key of G. You will play I=GBD; i=EGB; IV=CEG; V=DF#A. Now you have arrived at the Key of D.  

Key of D: Begin to play “Heart ‘n Soul” chord progressions like this: I=DF#A; i=BDF#; IV=GBD; V=AC#E. Now you have arrived at the Key of A.  

Key of A: Now you can begin to play “Heart ‘n Soul” with the Key of A progressions: I=AC#E; i=F#AC#; IV=DF#A; V=EG#B. Now you have arrived at the Key of E.  

Key of E: Now you can begin to play “Heart ‘n Soul” with the Key of E chord progressions: I=EG#B; i=C#EG#; IV=AC#E; V=BD#F#. Now you have arrived at the Key of B. As you proceed through each new slice, notice that you are adding a sharp until you reach the maximum sharps allowed, then the progressions move into the flats.