The output from them is available on the net as you know. One thing all Camp classrooms have been interested in is the role community members can play in gathering information such as current weather patterns. They all report the same information. There are two sizes. Humans are still used sparingly but mainly now as weather spotters.
Rainbows are an optical phenomena due to the diffraction of light waves.
I must sign off now. It has been a pleasure spending time with each of you online. I hope that we can do it agin in the future. Today was a very interesting and valuable session. Look for an excellent review of the chat when it goes up on the web archives.