COMMUNICATING WITH LIGHT
What is light?
Visible light is the only type of electromagnetic energy that we can see with the naked eye. The sun is our main source of visible light, but it can also be emitted by fire, light bulbs, and other devices. Light is what gives things their visible form, shape, texture, and colour, but, over the centuries, light has been used as a form of communication, too 1.
DO 1
Can you think of any other ways in which you use light to communicate?
Light messages
In ancient times, light was used to convey messages through fire, and the Romans used polished metallic plates for sunlight reflection to carry out long distance signalling. Later on, ships started using signal lamps to transmit messages in Morse code.