In Western music, the small interval from one note to the next closest note higher or lower is called a half step or semi-tone. Three half-step intervals: between C and C sharp (or D flat); between E and F; and between G sharp (or A flat) and A. Listen to the half steps in Figure 4.8.
The distance between the 3rd and 4th notes and the 7th and 8th notes are half steps. Those are the two naturally occuring half steps in a major scale. In a major scale, there are two naturally occuring half steps. In the key of C Major, those two half steps are between B & C and E & F.
