Pieces of music are written in patterns/structures called form. Two of the simplest forms are binary and ternary form.
Binary form
Pieces in binary form have two distinct parts. These are usually indicated by the letters A and B. Below is the children’s piece This Old Man. It is an example of binary form.
Note that not all pieces in binary form have exact equal sections. For example, the A section could be 8 bars and the B section 12 bars.
The note that finishes the first A section is very often not the tonic note (i.e. the “do” note of the key of the piece). A binary melody sometimes has each half repeated. However, this is not compulsory as is the case with the examples in this article
Sometimes the A and B sections of a binary form piece have similar melodic shapes. An example of this is Lavender Blue (shown below). However, this is not always the case as can be seen in “This Old Man”.
More examples of binary form can be found here.
Ternary Form
Pieces in ternary form have three distinct sections. The three sections are described as ABA. The second section is different from the first and third sections. The first part often ends on the tonic or a note that is part of the tonic chord. The B section usually ends on ‘sol’, ‘ti’ or ‘re’. Twinkle Twinkle Little Star (shown below) is an example of a piece in ternary form
Another example of ternary form can be found here.
I hope you have enjoyed this article and now have a good understanding of binary and ternary form. If you are interested in learning more music theory or would like to learn a musical instrument, we would love to hear from you. Either call us on 02 95892535 or click here to find out more about our music lessons.