- James Clerk Maxwell, combined three major fields of science into one theory when he introduced the Electromagnetic theory. This theory comprised of electricity, magnetism and light. According to Maxwell, light was an electromagnetic wave, and so he concluded that light carried the same proprties as all the other electromagnetic waves. He realised that electric and magnetic fields in the waves could support each other and be self-propogating, but only at one speed...the speed of light.

- This concept is a tricky one to understand, since most waves are 2D, but this one is 3D. In the example above, the electric field continues on it's wave motion on the Z plane, whereas the magnetic field continues it's wave motion on the Y plane. The whole wave propogates along the X plane.

- The Visible Light range can be simplified further to give us the visble light spectrum, whcih can also be achieved through dispersion of light, when white light is shown through an upright triangular prism.

- Newton had shown that white light could be dispersed into the colours of the visible spectrum through the use of a prism, he alos showed that the spectrum could b put through another inverse prism to produce white light again. The colours of the visible spectrum are of a similar wavelength. White light consists of all the wavelength in close to equal amounts.