The Colors of a Soap Film

Loved the small book "Soap-Bubbles and the Forces Which Mould Them" [1], [2], [3] by C. V. Boys.

He talks about the colors of soap bubbles (among other things). After reading it I watched a large bubble-sheet exhibit at the Exploratorium in San Francisco with fascination—noting how the colors were different at the top of the film, (where it is thinner) compared with the lower part of the film (where it is thicker).

As the bubble begins to evaporate and get thinner, it eventually becomes colorless (black, I suppose) just before popping.

Aside from the section on color, the whole book is a beautiful example of reasoning, the scientific method, etc. (as though presented to Physics students—but it is nonetheless easy for the layman to follow along).

[1] https://archive.org/details/soapbubblestheir0000cvbo/

[2] https://archive.org/details/SoapBubbles-English-C.V.Boys/

[3] https://www.gutenberg.org/ebooks/33370

Invert the process - That would allow you to build a thickness gauge from just white light and 3 sensors. Or maybe add a few more (there are multislectral sensors from ams osram) for robustness.

Not sure why you would need that though..

Similar effect in devices to measure polarization of light. You introduce white light and crossed polarization filters. Depending on the amount of rotation similar colour patterns emerge. I haven't seen an automatic device yet, but manual evaluation of the colors

What a lovely gradient pattern.

I’m also reading other content on the website right now, and I like the post “kaleidoscope-in-an-elevator.” I think it explains things very well.