Creative Science Centre: A Voice on a Sunbeam

Here is described a simple process to 'put a voice on a sunbeam' and transmit it over a distance. It is a fascinating example of amplitude modulation of light using sound vibrations. It then describes how the modulated light is detected and demodulated in a receiver so that we can hear the sound. A wide range of physics and engineering experience can be learnt through these exciting 'sunbeam' experiments. These activities are inexpensive and can be made in a school laboratory or at home.