How You See Color, part 2

How You See Color, part 2

In my previous post, I described how color is made up of light, and things that appear to be a certain color are actually reflecting that color.

Those colors of light are part of the visible spectrum – wavelengths that the eye perceives. There are many other wavelengths that the eye does not perceive. The whole spectrum is referred to as the electromagnetic spectrum. The longest waves are radio waves, and their wave length is the size of a building. Smaller waves, going down the spectrum, include microwaves, infrared, then visible, followed by ultraviolet, x-ray, and gamma ray. The visible spectrum has the longest wavelengths in red, getting shorter as you traverse the rainbow down to blue and violet. That is why heat, or infrared, has the word red in it. It comes right before red. Likewise, ultraviolet is just slightly shorter in length than visible violet light.

Theoretically, waves could be as long as the universe itself or infinitely short. The waves can carry information, like radio signals. Light also can transmit information, as in fiber optical cables.

Some wavelengths can be damaging to humans, like UV or ultraviolet, which sunblock can help protect against. Some wavelengths cannot easily penetrate the earth’s atmosphere. This group also includes UV, as well as most microwave, x-ray, and gamma ray.