With the aid of satellites we are able to quickly communicate over long distances. This demonstration uses a light beam to represent a radio signal being relayed from one place to another via a "mirror satellite."
Explain to the class that our telephones work via satellite. When someone calls us, for example, their telephone company's transmitter sends a signal up to its satellite. The signal is bounced off the satellite and received then translated into words by our telephone.
Ask for three volunteers and position them as the points of a large triangle. Give the CALLER a flashlight; the SATELLITE a mirror; and have the RECEIVER just stand. (You can also "put the SATELLITE in the sky" by having him/her stand on the teacher's desk.)
Darken the room and have the CALLER light the flashlight and shine it to the SATELLITE. He/she is sending a signal. The SATELLITE receives the signal from the CALLER and positions the mirror so that the light shines onto the RECEIVER.
IMPORTANT CONCEPT: In this demonstration, the students sent a beam of light from one location to another a few feet away. Satellites are able to transmit information quickly from one part of the earth to another.