Give students a melody (as a Sibelius or Finale file, accessible via school intranet if you want to save time). Using trial and error, asking students to write a harmony line, creating a duet. For the melody, you could use a nursery rhyme OR the Music: Count Us In song. EXTENSION: Explain how notes fit into chords. Ask students to write another duet, using only notes from each chord, and compare for the two duets.