We’ll start with the BASIC sandwich of musical form, what we might call an “Open faced” sandwich.
In a Nutshell:
Music with this form has two contrasting parts,
A: the “bread”
B: the “cheese”
One of the main things we need to remember is that the B section needs to do something different, maybe a different type of melody, new rhythm, or hanging out in a new harmonic land.
Here is a song that has a VERY basic BINARY form. This form is written as
A | B
or bread + cheese
You can hear that the B section “Land where my fathers” is definitely centered around a new note, and has a new tune. What you get here is an open-faced cheese sandwich.
Topics In Depth:
In Classical Music, Binary form often has repeats after both A and B
||: A : ||: B : ||
If those funny lines and dots are looking strange to you, then please go back to Music: Getting Oriented to Reading to learn about notation!
Here is a piece by Bach, the Orchestral Suite No. 2 “Minuet,” which includes those repeats.
The A section is centered around I/i, or tonic in Major and minor.
The B section is most likely going to be in V or Dominant in Major and III or Mediant in minor.