In this activity, students explore how sound production was used by ancient cultures as a communication tool over long distances.
The bullroarer is an ancient musical instrument used in rituals for communicating over extended distances and in ambushing animals. It consists of a rectangular slat of wood attached to a long cord. As the instrument travels around its circular path, the pitch appears to rise and fall as it moves closer to and farther away from the listener (Doppler Effect). By modifying the cord's length and/or the speed with which it is turned, the sound can be altered. This can be used to code messages over far distances.