1. Ritter and Herschel
Aim

2. Sir Frederick William Herschel
Discovered the planet Uranus and 2 of its moons in 1781.
Discovered Infrared radiation in1800.
Discovered two moons of Saturn.
Sir Frederick William Herschel
(15 November 1738 – 25 August 1822)

3. He measured the temperature of different colors of the spectrum by placing a thermometer on each colour.
He found to his amazement that the hottest part of the spectrum was in a place where there was no colour at all.
It was a region beyond the red end of the spectrum. For the first time it was possible to talk about invisible light.
This hot light became known as Infrared (below the red) because it was shown to have longer wavelength than visible light.

4. After learning about William Herschel's discovery of infrared light, Johann Ritter began to conduct experiments to see if he could detect invisible light beyond the violet portion of the spectrum as well.
Johann Wilhelm Ritter
(16 December 1776 – 23 January 1810)

5. In 1801, Ritter was experimenting with silver chloride, a chemical which turned black when exposed to sunlight. He showed that silver chloride turned black faster when exposed to a region which was beyond the violet region. (UV radiation).