Creating music lesson plans about percussion instruments is easy with a few ideas detailed below.
To help students understand how timpani can be tuned, demonstrate the effect of membrane tension on pitch. With a simple home made drum, pull on the edges of the drumhead to put varying degrees of tension on it, while a student plays a steady drumbeat on it. Students can get into pairs and take turns exploring the effect of tension of skin on the drum’s pitch.
Explain how the bars on the glockenspiel, xylophone, and marimba are laid out like the keys on a piano, with a row of “white” keys along the bottom and “black” keys (chromatic tones) along the top. Have students make a “paperphone.” Students can cut out rectangular bars of continually smaller sizes out of paper and glue them to thick cardboard or a large sheet of paper. You can then put labels on the bars.
Show the students how resonance amplifies the sound of a musical instrument. With a xylophone or marimba you can remove one bar and try and play it with no resonator (pipe or box) underneath. Then compare the difference with placing it over the resonating chamber. It may necessary to have a go first with the instruments around the school first to make sure you can clearly demonstrate this using your instruments.
Here is a great recording to check out: Béla Bartók, Music for Strings, Percussion, and Celesta, III. Adagio. This movement has prominent parts for xylophone and timpani. The timpani performs glissandi throughout, an excellent demonstration of its pitch capabilities.