What exactly is light? Is it a wave? Is it a particle? Is it a mythical being? This question has been debated for many centuries. Some have claimed it was a wave. Others claimed it was a particle. In the early 19th century, Isaac Newton proposed that light was composed of particles, but the answer was not accepted until after an experiment by Thomas Young. Young's basic experiment consisted of a coherent light source such as a laser beam passing through and illuminating a plate containing two parallel slits and observed on a screen behind the plate. What exactly were the results of this historic experiment? Young's experiment showed that light behaves with the characteristics of both a particle and a wave. He observed that when the light source passed through the slits and was projected onto the screen, it diffracted and produced an interference pattern, or series of bright and dark lights on the screen. If the light contained the characteristics of a classical particle, as some such as Isaac Newton suggest, then the light would not have interfered with the passage of T....