As you well know, soap bubbles exhibit wonderful iridescent color patterns. their origin is similar to the effect that makes oil slicks colorful (see explanation in muller's book): the reflection of light at the two sides of the very thin soap film. look up what the word "iridescence" actually means and explain, why this effect occurs for soap films. if you feel a little schematie picture might your argument, feel free to supply one. (hint: interference! )