Hear from deep space. Pupils learn how satellites transfer information back to Earth. They learn about three different ways to modulate radio waves and how a satellite sends information with only 0s and 1s. Using sound, class members...

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...