My 8 years old daughter was blowing soap bubbles. Most of the bubbles had color. She randomly choses a bubble with colors and lands it on the wand. Instantly it's color is gone. If she blows this bubble again in air it remains colorless, while the surviving bubbles in the air still show colors. Why is this happening, what is happening on impact that causes the bubble to lose its colors permanently? I have done it multiple times and the observation is constant irrespective of the bubble size. Let me clarify from the onset that I am not a physicist, in fact I am a biologist. But thus caught my attention and hence positing.
I cannot be sure the following is the correct mechanism, but maybe part of liquid moves from the bubble to the wand, the bubble becomes thin, so the interference conditions are not satisfied for any wavelength of visible light, so the bubble loses colors. When you blow the bubble again, it does not become thicker and so it does not acquire colors.