Why Clouds are White--Part 1.895

  My story of Why Clouds are White reminds me of the children's book If You Give a Mouse a Cookie in which a young boy is run ragged by a mouse who asks for a cookie, then a glass of milk to go with the cookie, then a straw for the milk, then a napkin to wipe is little mouse lips...et cetera.  My story is called If you Give a Writer a Question... 
   She will probably enter "why clouds are white" into a search engine. When she reads over and over that clouds are white "because they scatter all wavelengths of visible light," she thinks everyone is chickening out of answering the question, so she studies "scattering" in her meteorology books and eventually draws some pictures (below) and writes a few things about scattering. 

  She will understand the idea of scattering (being a bit scatter-rained herself) but doesn't understand why the sky is blue and not white and why the clouds are white and not blue or rainbow colored. She has read that it has something to do with size of wavelengths and particles, but "big" and "small" have become meaningless and she is way down in the rabbit hole where she finds an answer. Only it looks like this: 


    Which does not make for very compelling reading.* So the writer plunges head first into figuring out what this means with the help of several books on physics, optical phenomena, and atmospheric antics. 
  And then when she has just enough learning to be dangerous, she heads back onto the Internet with a very  question about the interaction between sunlight and water, specifically, how the wavelengths of light interact with the water molecules that make up the cloud droplet. Having asked this question, the writer will probably want to spend an entire week on understanding the answers. 
    She will find herself on the NASA website and then the Max Planck Research School for Atmospheric Chemistry and Physics where she will giggle when she  discovers her answer might come from a group of scientists called SATCHMO, the acroymn for Synergetic ATmospheric Transport CHemistry MOdellers. But they are in Mainz, Germany, and because she does not speak German or understand physics, she decides to bookmark the site and move on.
   She is lured into  hyperphysics, where she spends an entire day there (due to her Attention Surplus Disorder), she e-mails a few meteorologists,  joins Open Study--a  website where 100,000 students from 1,600 schools in 170 countries can ask questions, give help, and connect. The site claims that "75% of questions are answered in 5 minutes."
   At 10:39 a.m., she submits her question. She waits. And waits. Five minutes passes. She is the 25%. She waits some more. In an hour comes a reply. It is a link. She clicks it and is transported to a classroom at MIT where she watches a Physics 803 lecture  on Rainbows given by Professors Walter Lewin. Lewin is charming and articulate and she sits there for 50 minutes and learns how light can behave inside a raindrop. It goes something like this:
     But not how light behaves inside a cloud droplet, which is much smaller than a raindrop. And moreover, this looks like geometry! The raindrop is just a circle and the light is just straight lines. She posts a thank you and follow up question on OpenStudy and is told her question is beyond the scope of first year Physics. Certainly someone can tell me what is going on inside that circle and along those lines. Anyone? Anyone?

Next posting...
The Accidental Naturalist goes to the library and finds Mr. Anyone: Richard Feynman

...describes the relationship between the circumference of a particle (pi times the diameter) and the wavelength (lambda symbol). If the particle is larger than the wavelength (particle size divided by wavelength), X will be greater than 1; if the particle is smaller, X will be less than 1; if the particle and wavelength are the same size, X will be 1. That number, 1, is not a measurement of size but a parameter. The size of what is being measured is in micrometers and nanometers. Depending on the value of X (=,<,> 1) the light will be scattered in different ways. But why? I don't know yet. Stay tuned for the why of blue skies and white clouds and rainbows.