In the middle years, investigation should continue into timbral description. As well, students should begin to discover how timbre can be changed and the effect this can have on a musical composition. Composers create various textures by combining sounds, instruments or voices to achieve expressive effects. The texture may be thick, thin, dense or transparent. Harmony is one aspect of texture.
Harmony occurs when two or more sounds are heard simultaneously.
Principles of Composition Principles of composition are tools or devices that help organize sounds and the elements of music into cohesive works. Middle years students should investigate such principles of composition as variety, repetition, balance, acoustics, transition, tension and resolution, and unity. Exploration related to the elements of music and principles of composition should be taught within a context of interest to the students. Students need to realize it is the interaction, not the isolation, of individual elements and principles that is important in music. The following outlines what the students should experience for the principles of composition in the middle years.