Sounds can be made by twanging a string or an elastic band, blowing down a pipe, banging something together, and scraping or shaking something. There are three families of musical instruments - string, wind and percussion. When a string is plucked on an instrument such as a guitar, the vibration is passed into the air and you hear a sound. Blowing into panpipes or a horn makes the air inside the pipes vibrate. Bongos and other percussion instruments produce vibrations when you bang them.
Sit the children in a circle. Demonstrate a simple drum rhythm, then pass the drum around the circle, asking everyone to first copy the rhythm and then to extend it. Introduce a glockenspiel in a similar way, so two instruments now travel the circle. Ask a pupil to introduce a third instrument. In smaller groups, pupils could improvise short pieces using instruments from two or three different families (percussion, strings or wind instruments). Encourage one member of each group to provide a steady beat for the others to work around. If using a xylophone, glockenspiel or chime bars, a pattern with harmonies is particularly satisfying. The following combinations work well: C G and A, or F C and D, or G D and E, or D A and B. Pupils could add claps, whistles, finger-clicks and their voices to the mix. When the children have had time to explore and improvise, encourage them to settle on patterns of sound they can remember and repeat. Allow time for each group to share their work with the class.