Short pieces of accentuated music are played from tape. On every larger accent (e.g. drumbeat), a PET bottle rocket launches with a bang into the air and flies up to the ceiling.
How does it work?
The bottles contain a precisely measured mixture of petrol and air, which is ignited by means of an electrical spark. With a hand-held Tesla transformer flashovers are generated to the rhythm, which are passed on to ignition plugs in the bottle neck.
Safety reference
A small darting flame develops only when the bottle rocket is launched. The flame disappears after fractions of a second, so there is no danger of ignition. In case of doubt, please have the feasibility of this experiment on stage clarified by a fire watch.