# Music Theory Reference

## Scale

Let's look at a fragment of a piano keyboard having an interval of 1 octave (e.g. between two C notes).

How many ways are there to get from the first C note going up to the next one on the piano keyboard? Apparently, a lot! Here are three examples:

1. Let's play without missing a single note. Each step is a semitone and we reach the next C in 12 steps (an octave has 12 semitones):
CHROMATIC SCALE (13 NOTES, 12 STEPS)
2. The next is a repeating “semitone - tone - semitone - tone” sequence and it takes 8 steps:
DIMINISHED SEVENTH CHORDS SCALE (9 NOTES, 8 STEPS)
3. And this one takes just 7 steps - "tone - semitone - tone - tone - semitone - tone and a half - semitone":
HARMONIC MINOR SCALE (8 NOTES, 7 STEPS)

Each of the ways to walk an octave in one direction is called a scale. The note you start at is called the root.

The distance between two sequential notes in a scale is called a scale step. E.g. in the last example the 1st scale step is from the 1st scale note C (root) to the next scale note D, the 2nd scale step is from the 2nd scale note D to the next scale note D♯.