Lesson Objectives:
To understand the use of ternary form
To analyse and understand the harmonic structure
To understand what is meant by modulation
To understand what relative keys are
To choose a performance or composition task
Ternary Form
Purcell chooses to use ternary form (ABA) for his setting of ‘Music For a While’
The B section contrasts with the A section and the return of the A section is changed slightly and is shorter with only the 1st two lines being repeated.
Harmonic Structure
We know ‘Music For a While’ is in A minor but like much music, it doesn’t stay in the same key.
Here is a diagram of the harmonic structure (different keys visited) and how that ‘fits’ with the ground bass repetitions.
Modulation
When a piece of music changes key, we say that it has modulated (moved) to another key. In ‘Music For a While’ the music modulates in the B section
If you are composing in a minor tonality the two most common keys to modulate to are the dominant and the relative major and this is what Purcell does!
Relative Keys
Keys are called relative because the major and minor scales share the same key signature (how many sharps or flats) A bit like sharing the same eye colour as one of your parents!
Review Questions:
1) What is the structure of ‘Music for a While’?
2) Name three keys that Purcell modulates to in the B section
3) What is the relative major of A minor?
4) What is the dominant of A minor?
5) What is the relative major of this key?