The Spectrum

Light illuminates our world and is all around us.  The suns light is the primary source of heat for our planet. Without the heat from the sun, the earth would be so cold that life as we know it would not exist. Light makes it possible for us to see and it also provides us with colour. Without light we would live in total darkness, but it must reflect off objects before we are able to see them. Lastly, light provides us with food. The way it does this is through photosynthesis. Without photosynthesis green plants would die. Without green plants to eat, animals count not live. Carnivores would also die because they would not have plant-eating animals to eat.

One of the most fascinating facts about colour is that all colours come from white light. White light contains all the colours in the colour spectrum. From these colours, all other colours are made. When substances are uneven in their thickness such as a wedge of glass, the combination of colours can break up and the colour waves separate.

Sir Isaac Newton was one of the first people to study light scientifically. He experimented with light, so he could learn more about it. One experiment he did was to direct a beam of white light through a triangular bar of glass, called a prism. He discovered that the light coming out of the prism was separated into bands of colours.

Sir Isaac Newton
1643 - 1727

Scientists call the arrangement of colours produced by a prism a spectrum. We now know that water droplets in the air, also act like tiny prisms which is why we often see a rainbow, after it rains.  There are many ways of producing light. Different sources of light give off different colours of light. This suggests that the study of light involves more than the white light produced by the sun.