These three terms are often confused. They refer to the same subject but in different ways.
Scale
- A scale is a series of (usually 7) consecutive note pitches finishing an octave above the first note.
- The series can be extended over several octaves and is either played in ascending or descending order.
- The first (and last) note of a scale is called the root note or tonic.
Mode
- A mode is the pattern of intervals between the notes of a scale.
- The pattern is based on the first note of the scale, the root note.
- Western modes are made up of an irregular combination of (usually 1 and 2 semitone) intervals. This gives each mode a unique character called its tonality.
Key
- A key is the use of the notes and tonality of a scale in a piece.
- A piece is “in a key” when it uses the notes of a scale in such a way that the tonality of its mode is apparent overall when listening/playing.
Tonality
- Tonality is the unique character of a mode, common to all keys in that mode.
- The tonality of a mode is simply indicated by the mode’s name.
We should learn to recognise the tonality of the more common modes, both in a scale of that mode and in music written/played in that mode.
Names Of Scales And Keys
Scales and keys have the same names. They are named as the name of the root note followed by the name of the mode. For example:
- the major scale on C is called C major.
- Music using the notes of C major is in the key of C major.
For more on scales, modes and keys see 8. What is a scale?, 10. How To Find The Notes Of A Scale, 11. Introduction To Keys And Key Signatures: Major Keys.
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