Hazmats

(Class of weds 2 May)

There's been a steady level of interest in rocks and fossils, chert and flint. Reading up on these, I stumbled on an interesting tidbit of information: limestone, when you add hydrochloric acid, should fizz. That sounds like good demo material! sez I, and immediately rummage for the concentrated hydrochloric acid, which is in the garage of course (you can buy it at professional plumbing supply houses under the brand name Vanisol).
I also figured this was a good time to show the similarity between shell and limestone, so now I had two things to douse with acid. And every experiment needs a control, so I also got a chunk of granite. Also a nice chunk of deer bone from the back acreage, because you might wonder Is Bone The Same As Shell?
I was not too excited about the idea of bringing concentrated acid into a kindergarten classroom, though, which is where the TeeVee and digicam come to the rescue. I could do all the dousing and fizzing at home, take little bitty movies on the digicam, and then pipe them into the class TV and show everybody!

It worked! So we had Home Movies of Science Demo.

I suppose I could post the actual movies but they add up to about 200MB. Suffice it to say, the limestone and shell both fizzed gratifyingly and then dissolved away to absolutely nothing. The bone (which was one of those old white dry things that look like they've been there an awfully long time) didn't fizz (it's CaPO4, not CaCO3), but interestingly enough after awhile it mostly dissolved but left behind a little gummy mass which was obviously the protein portion - - even after a few seasons of ants and bacteria and rain and drought, there was a good deal of protein intermixed with the mineral part of the bone. Whadda ya know - - next time you're lost in the wilderness, don't turn your nose up at old bones!