I like to use a Hoberman sphere (http://goo.gl/GTEmXh) as a tool to show my students how to play effective dynamics.
The expansion and contraction of the sphere is a fantastic visual that helps the students to play with contrast. It works best with crescendos and diminuendos. It is also a great way to reinforce correct breathing by expanding the sphere as the students take a deep breath.
Keith Ozsvath
Rotolo Middle School
Batavia Illinois
