The Internet to the rescue once again!

Last night, while reviewing the different forms of chemical weathering for today's Soils class, I got to thinking about hydration (one of the common weathering events). And I got to thinking about those little pink and blue humidity indicators that you used to be able to get in Cracker Jacks, back when they had marginally decent prizes (instead of the piece-of-crud "temporary tattoos" and poorly-glue-bound "riddle books"). But I couldn't remember what chemical it was, or whether it was pink for nice weather or pink for rain.

And so I did a Google search. After a few false starts (did you know that "kitchen chemistry" turns up some verrrry weird sites?), I found it:

make your own Cracker Jack-style weather predictor. It uses cobalt chloride, which frankly doesn't sound like something I'd want stuffed in with my candy coated corn and peanuts, but then again there were a lot of things I consumed as a kid that I'd probably be horrified at today.

and for the record: it's pink for a storm, blue for a clear day, purple for rain. Supposedly. But since it's just a humidity meter, I know if I had one, it'd be showing "storm" all summer long even though we're in a drought because the summers where I live are approximately 164% humidity* all day every day.

More simple and more or less harmless chemical demonstrations

*and don't lecture me about how you can't have more than 100% of anything. I know that. I'm doing that for effect.