One of the most fascinating aspects of fluorescent lights is that despite the uniquely bright light that they emit, they rely heavily on a part of the light spectrum we cannot see.

Conventional fluorescence works by using electricity to activate a combination of an inert gas (such as neon), mercury, and electricity to cause the former two to emit UV light that is converted to fluorescent light via a phosphor coating.

Interestingly, the concept of ultraviolet radiation was discovered by a pioneering German chemist based largely on a hunch.

In 1800, William Herschel discovered infrared radiation (at the time known simply as “heat rays”) as part of his fascination with astronomy, finding a light that was impossible to see but was detectable with a thermometer.

This inspired Johann Wilhelm Ritter, and he spent the better part of a year looking for a way to test the opposite, assuming that if there was light beyond one end of the visible spectrum, there must be one at the other side. If there was an infrared, there must be an ultraviolet.

In between his early works in electrochemistry, electrolysis and electroplating, he strove to prove 

a core belief of his that “forces of nature” are caused by the relationship between two extreme ends of polarities. 

Whilst this was not universally true, it happened to be correct when it came to the light and colour spectrum, although he ultimately proved it by accident as well.

He did not necessarily find it to be an exact opposite force; he was looking for “cooling” radiation 

at the opposite end of the spectrum and ultimately did not find it.

However, he did find ultraviolet light through experiments with silver chloride, which reacts to heat by turning from its typical white hue to black.

What he found was that silver chloride exposed to a form of invisible light beyond violet reacted faster than any other colour, and these “chemical rays” were quickly found to be connected.