**Introduction**

An **interval** is the distance between two pitches. They can be **melodic **(played one after another) or **harmonic** (played simultaneously). All intervals are identified by number size and quality.

melodic interval:

harmonic interval:

**Interval number**

An interval is named by its **number size**–the number of scale steps it encompasses, including the first note as “1.” Thus, C up to E would be a *third*; G up to F would be a *seventh*; and E up to A would be a *fourth*.