The scale you saw in the last lesson has a certain pattern of whole tones and semitones.
C to D | whole tone |
D to E | whole tone |
E to F♯ | whole tone |
F♯ to G | semitone |
G to A | whole tone |
A to B | whole tone |
B to C | semitone |
If you form a scale using the same notes, but start on a different pitch (D in this case), the pattern will change:
D to E | whole tone |
E to F♯ | whole tone |
F♯ to G | semitone |
G to A | whole tone |
A to B | whole tone |
B to C | semitone |
C to D | whole tone |
Each different pattern in a scale is called a mode. We will learn more about modes later, but for now we are going to focus on one specific mode called the Ionian, more commonly known today as major. Using the scale from the example, we will get this mode by starting on G.
G to A | whole tone |
A to B | whole tone |
B to C | semitone |
C to D | whole tone |
D to E | whole tone |
E to F♯ | whole tone |
F♯ to G | semitone |
This pattern can be applied to any note to build an Ionian (major) scale.
Each pitch-class, or letter, must appear exactly once in any given scale. This determines the correct "spelling" (i.e. whether to use F♯ or G♭.)