G7-Beyond Visible – The New Photovoltaic Technologies-800-900L-03

Energy from the Sun

At one time, it was thought that the light we see was a single homogenous entity. We know now that white light is a combination of different colors. These colors represent different wavelengths of light. All of these wavelengths are just a small part of what scientists refer to as the electromagnetic spectrum (EMS). Some of the electromagnetic spectrum can be seen when viewing a rainbow. Rainbows occur when light passes through water droplets. As light hits the droplet, it is refracted or bent. This bending of light rays causes the light to be broken apart into its individual wavelengths or colors.

This same effect helped William Herschel to discover infrared (IR) radiation. The IR wavelengths are just beyond the red visible spectrum. It was quite the scientific breakthrough. What he had noticed was temperature differences in light passing through a prism. Passing white light through a prism splits it up into the several colors of light. Herschel noticed that the highest temperature was reddish light. Blue colors are cooler in temperature. A year later, Johann Ritter made another important discovery. He was working at the other end of the EMS when he found what he called “chemical rays”. These invisible light rays were capable of causing chemical reactions. These chemical rays were later renamed ultraviolet radiation. It is important to know that energy exists beyond the visible light spectrum we are able to see.