Section 2.2 The Major Scale
A major scale contains a specific succession of whole and half steps. It is helpful to think of the pattern as consisting of two tetrachords. (A tetrachord is a four-note scale segment.) The lower tetrachord consists of the pattern whole step, whole step, half step. A whole step joins the lower tetrachord to the upper tetrachord. The upper tetrachord duplicates the pattern in the lower one: whole step, whole step, half step. If we use W for whole step and H for half step, the major scale pattern is W–W–H, Whole–step connection, W–W–H.
All major scales use the notes of the musical alphabet in order; no notes are skipped and no notes occur twice. In the example above, the first four notes are \(\text{D}\)–\(\text{E}\)–\(\text{F}^♯\)–\(\text{G}\), not \(\text{D}\)–\(\text{E}\)–\(\text{G}^♭\)–\(\text{G}\). In \(\text{D}\)–\(\text{E}\)–\(\text{G}^♭\)–\(\text{G}\), \(\text{G}\) erroneously occurs twice and the \(\text{F}^♯\) between \(\text{E}\) and \(\text{G}\) is skipped.
