Preppy Physics

Many interference phenomena that are seen in the natural world are characterized by alternating bands of pinkish-purple and aqua colors. These can be seen in oil films, soap bubbles, interference from scratches, supernumerary rainbows, glories, and other places where multiple orders of interference are present and the light source is broad band white light. It was such a clear manifestation of a common optical effect that it was very early on incorporated into computer simulation software. The effect also shows up in many basic optics experiments, such as on the edges of single-slit interference patterns. Why does white light multiple-order interference tend to produce aqua and pink colors?