Changes

The "distance" from one note to the next in the chromatic scale is called a ''semi-tone '' or ''half-tone''. So A - A# or E - F is one semi-tone. A ''whole-tone '' is 2 semi-tones. So A - B is a whole-tone, just as A - A# and A3 - B are two semi-tones.

Sometimes whole-tones are called ''whole steps '' and semi-tones are called ''half steps''.

'#' means "sharp". 'b' means "flat". These terms indicate the named note is raised or lowered one semi-tone. Multiple sharps and flats can be used. For example, Abb is 2 semi-tones below A. Abb corresponds to the same frequency as G. Similarly, G# is the same frequency as Ab, and B# is the same frequency as C. For our purposes, we are unlikely to ever deal with double (or more) sharps or flats. But it's important to understand what they are to remove some of the mystique from them.

The major scale is composed of root, +1 whole step, +1 whole step, +1 half step, +1 whole step, +1 whole step, +1 whole step. Another +1 half step gets us to the octave of the root note. In other words, 2 whole-tonessteps, a semi-tonehalf step, 3 whole-tonessteps, and a semi-tonehalf step. Below is the chromatic scale starting on C, then the C Major scale. The sh's represent half steps (semi-tones ) and the w's represent whole-tonessteps. The chromatic scale consists of 12 semi-tones.

s h s h s h s h s h s h s h s h s h s h s h sh

w w s h w w w sh

w w s h w w w sh

Notice how the major scale is really just a whole, whole, semi half sequence, then a single whole tone, then another whole, whole, semi half sequence. (w w sh) w (w w sh). The (w w sh) sequence is called a tetrachord (actually has 4 notes), and is historically very important in the development of music. It is our Do Re Mi Fa melody from above.

Notice also how we say Do Re Mi Fa So La Ti Do, and not Do Ti La So Fa Mi Re Do. In other words, by default, we are singing the ascending version of the scale. Whether we sing it ascending or descending doesn't change the fact that these notes form the major scale. However, it does reveal a bit about the scale itself. When we sing the scale, we encounter two semi-tones. Semi-tones, by nature are the most dissonant (non-harmonic) two notes in the 12 tone scale. Notice the location of the semi-tones in the major scale. There is one between the third and fourth note in the scale, and one between the seventh and the octave. If we are singing the scale ascending, that means our seventh note will be the most dissonant and create the most tension. Remember that our tonic note is like gravity - we find the most release there. So not only is the seventh note the most dissonant note in comparison to the tonic, it is its neighbor in the scale, and will occur directly before reaching the tonic note in the ascending scale. The seventh is often called the "'''''leading tone" ''''' because it leads into the tonic.