- According to the Explorium website, the colors in a soap bubble originate from white light, which contains all the colors in a rainbow. Think back to basic science and the explanation of the properties of white and black. White contains every color of the rainbow, while black is the absence of any colors of the rainbow. When a white light is shining on a soap bubble, it interacts with the properties of the bubble. Every color will shimmer, disappear and reappear on the bubble until it finally pops.
- White light is composed of waves, such as seen in a body of water. Light waves are the same as frequency; this is the number of times a wave vibrates in a single second. The faster the frequency or wave, the deeper and more intense the colors on a bubble will be. If the electromagnetic vibration is approaching 732,000 times in 1 billionth of a second, you will see a violet color on the skin of the bubble. Look at a picture of a rainbow. Violet is the most intense color, meaning the vibrations are at the fastest possible rate for one of the colors of the rainbow. When you see "white light," you are seeing light waves of several frequencies taking place simultaneously. When a light (from a flashlight) is directed on the surface of a bubble, you will see every color in the rainbow moving and shimmering on the bubble.
- Light waves from different sources can interact with each other. One wave can cancel the other out: For instance, if one wave pushes in one direction while the other one pushes in the other direction, the effect is called "destructive interference." When this kind of interference takes place, some colors of the rainbow will be canceled out. However, if the waves work together (pushing up or down at the same time) the colors will become brighter and more intense. This is called "constructive interference." An individual soap bubble is composed of several layers--one is a layer of soap, the other is a layer of water and the last layer is another layer of soap. As one set of light waves from one soap bubble layer interacts or interferes with the light waves from the second layer of the soap bubble, both sets of light waves interfere with each other. As each set of light waves works with each other or against each other, the colors that are left are called "interference colors." These interference colors depend on the thickness of the bubble's skin and how far the light waves have to travel before they bump into each other. This is influenced by the bubble's thickness. At its thinnest, the waves will cancel each other out and the soap film will look black--and then the bubble pops. Light waves and color on a bubble will show up the best with a white light and a black background.
