Physics- Electromagnetic Waves

History on the electromagnetic waves

Visible light (red, orange, yellow, blue, indigo, violet) is a type of electromagnetic wave. However light did not need to be discovered- everyone knew of its excistence. 

In the year 1800 a famous German/British astronomer William Herschel made an important discover. He was experimenting with light and a prism. Herschel added a twist to the experiment Isaac Newton had done over 100 years beforehand. Herschel's most excellent experiment was when he put a thermometer above the red light that came out of the prism. When he did this he discovered that the thermometer started reading higher temperatures, he had discovered invisible rays that caused heating near the red light of the spectrum. These are now called infra red rays.

A year later this experiment was the inspiration for another German Physicist (Johann Ritter) to see if there were anymore invisible rays the other side of violet. This time a thermometer wasnt used, instead a photographic chemical (silver chloride) was used. When the silver chloride was placed below the violet it turned dark. The silver chloride even turned darker quicker than it normally would with visible light. This meant another…