Fragmentation is an interesting tool which composers can use to generate a plethora of melodic material with very little effort. In my opinion, there are two primary types of fragmentation, subtractive and motivic.
Subtractive fragmentation is easy to do and, if used properly, creates syncopation. All you have to do is substitute rests for notes. Example No. 1 is an original melody which I have used in a number of previous blog posts. Example No. 2 is the same melody with rests replacing some of the notes. Play both examples and listen to the difference. Example No. 2 is clearly the same melodic idea, but it has more rhythmic punch because the rests create accented upbeats in measures 2 and 4. The quarter rest in measure 3 creates additional rhythmic interest.
Example No. 1
Example No. 2
Motivic fragmentation is more common than subtractive. In fact, it is an integral part of classical period repertoire and is common in compositions by Haydn, Mozart, and Beethoven. In general, the primary thematic structures used in classical period music where the sentence and period. It is beyond the scope of this blog post to discuss thematic structures in classical period music, but, in general, a basic idea is introduced (usually two measures), repeated creating a four measure theme, then a fragment of the basic idea is extracted and sequenced three times to create a classic eight-measure sentence structure. In example No. 3, the eighth notes in measure 2 are extracted and sequenced three times to create an ascending melodic line which cadences in measures 7-8. This creates a sense that the melody is accelerating toward a cadential point.
Example No. 3
Comment if you can think of any other types of fragmentation. In the meantime, apply these techniques to your own compositions and listen to the results. Happy composing!