We think it is important for students to compose the bulk of their piece linearly with just one instrument. This does two things:
Keeps them focused on the melodic content for each section of their piece.
Allows students to think on a large enough scale to plan out the overall form of their piece.
After students have their piece in A-B-A form we can begin to explore consonance and dissonance when adding a second instrument to create harmony.
If you have come across this topic note that it relates to the Melody Module on the Music Works 1 collection here. Check it out for more info!