ELECTROMAGNETIC SPECTRUM

Electromagnetic radiation is a form of energy that can move through empty space. The category includes X-rays, visual light, and radio waves. The problem with radiation is that it's not just a particle, and it's not just a wave. It's neither -- and it's both. In other words, it's indecisive.

T he rainbow of colors that we see in visible light represents only a very small portion of the electromagnetic spectrum. On one end of the spectrum are radio waves with wavelengths billions of times longer than those of visible light. On the other end of the spectrum are gamma rays. These have wavelengths millions of times smaller than those of visible light. The following are the basic categories of the electromagnetic spectrum, from longest to shortest wavelength: