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Why do soap bubbles have many colors? Why do they sometimes swirl?

Rainbowing of any sort is caused by the differential refraction of light waves, breaking the light into its component parts which we call colors. In the question you asked about rainbowing on the bottom of a stainless steel pot, the rainbowing you see is due to different thickness is of oxide taking the light in your environment and breaking it into its component colors depending on the thickness of the oxide in the various areas. With the soap bubbles, the different thickness' of the soap film forming the bubble will also separate the light differently depending on the soap film thickness. The reason you see the swirling is that, as you blow on the bubble, or as air hits it, the areas of thicker/thinner soap film thickness move on the surface of the bubble, and you see the light reflected off the bubble changing according to the diffraction caused by the changing soap film thickness. I hope this answer is clear to you. Please write to me, or ask your teacher or parents if you need further explanation.


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