If you are a musician, or not a musician, you may have noticed that when two different notes are played a regular series of pulses is heard. An advantage of the wave theory of light is that it explains how light can bend around objects. Though the waves cannot penetrate the pier, at the end of the pier the waves bend around this obstacle. This bending of waves around objects is know as diffraction . You can experiment with this phenomenon while taking a bath.
Red light is diffracted more than blue light.
Diffraction of light around a small object results in bright and dark bands that result from the interference of the light waves striking different sides of the object. You will see bright and dark bands of light. On a bright day, carefully look at a shadow cast by a pencil on a piece of paper and you'll see a bright region around the tip. If you had an occasion to wear glasses at night with drops of rain on them, you may have noticed bright and dark rings around the drops when you looked at a light. The color bands result as different colors are removed from the sun's light due to destructive interference, while other colors are enforced due to constructive interference.