Basic Intervals: Half and Whole Steps – The distance between two tones is termed an interval. The smallest intervals are those of half and whole steps. These occur between adjacent letter names on the staff. On the white keys of the piano, there is a half step between E-F and B-C. Between all of the other letters, there is a whole step. It really is that simple.

Fig. 57

The whole steps may be divided into half steps by the use of sharps and flats.

Fig. 58

If the two tones comprising an interval occur together in time the interval is harmonic. If they occur one after the other then the interval is melodic. In order to name intervals accurately, it is necessary to have two terms.

1. Quantitative – This represents the number of letters involved, including the first and last.
2. Qualitative – This requires an additional modifying term. For example, C to D is called a major second (a whole step), while E to F is a minor second (half step). While it is possible to describe larger intervals in terms of the number of half steps each contains, this is usually not done because larger intervals are described by relating them to the normal occurrences in the major scale.