People normally think of light as what we see when we open our eyes. Specifically, the light that lets us distinguish different colours and what makes the difference between day and night. But what we see on a daily basis is only part of the spectrum.
Light, in the scientific sense, is electromagnetic radiation. It consists of eight regions, depicted in the figure above. The most well-known regions are visible light, infrared, and ultraviolet light (UV light) The human eye can only see, as the name implies, visible light. This part contains all the colours in a rainbow. Infrared light and UV light are not visible to the human eye.
Ultraviolet light, which is literally “past violet,” has its own various regions. The first is UV-A light, this is also called blacklight. This light consists of long waves and is known for speeding up the ageing process. UV-B Light consists of middle length waves and causes sunburn and tanning.