The way light is emitted is by electrons circling around the nucleus of an atom. An electron that has a low energy level, travels closest to the nucleus. The level of energy throughout the atoms circling the nucleus changes all the time. And then we're back on the subject of a photon because of the fact that the electron emits energy in the form of a photon.

There is a different level of energy for each atom making it unique. An atoms "fingerprints" are the spectrum which is emitted by photons. What is quantum theory? They're like the laws of atoms.

Electric and magnetic fields go along with light when it is in the form of a wave. Electromagnetic waves are little force fields that stay around to charge particles. Eletromagnetic waves vibrate. All natural sources of light have irregular light waves.

O.K., now we're going to talk about wave length. A wave length is basically the distance between two wave peaks. Nanometers (nm) are the unit of measurement used to measure visible light waves. They are very, very, very, very, very small! They are about 0.4 ten-millionth of an inch long. That's very, very small.

The entire range of frequencies and or wave length of electromagnetic waves is the electromagnetic spectrum.

A lot of us know light as a range of frequencies that can be seen by human beings. These waves of light have very high frequencies. They're always from 400-700 nm.

Infrared lights are waves with frequencies that are a little lower than human vision. Ultraviolet rays are the opposite. Our eyes see a slightly different color with each wavelength or frequency of visible light. The very longest wavelength that humans can see is a deep red that is about 700 nm long and the very shortest is violet or deep blue which is about 400 nm long. Our eyes respond best to light that is green which is 550 nm long.

I know you're getting tires of photons but we're going to learn some more. You could describe them as packets of light energy. They are very unlike conventional particles like little pieces of dust or marble. Electromagnetic waves and photons are always associated. A photon carries just a little energy. A large number of photons are produced from the sun.

Hot atoms collide with each other when in an incandescence light source. Some electrons get energy from these collisions, therefore boosting them to higher energy levels. They emit photons when they emit this energy. (Oh no! Not more photons?!)