Colour is light, which travels to us in waves from the sun, on the same electro-magnetic spectrum as radio and television waves, microwaves, x-rays etc. Light is the only part of the spectrum that we can see, which perhaps explains why we take it less seriously than the invisible power of the other rays. Sir Isaac Newton demonstrated that light travels in waves, when he shone white light through a triangular prism and, when the different wavelengths of light refracted at different angles, he was able to demonstrate that the colours of the rainbow (the spectrum) are the component parts of light.