Students will enjoy learning about how the timpani are tuned by exploring the effect of the skins tightness on its pitch. With a coffee can drum (see lessons on Untuned Percussion), pull on the edges of the drumhead to put varying degrees of tension on it, while a student plays a steady drumbeat on it.
here is a few fairly simple ideas for creating music lesson plans about percussion instruments. To help students understand how timpani can be tuned, demonstrate the effect of membrane tension on pitch. With a simple home made drum, you can often vary the tension of the skin by simply pressing or pulling at the edges