If you had been in our mod (our temporary building) yesterday you would probably have called the office with concerns about smoke and a burning smell. Most teachers on my hall did.
We've been studying states of matter (solid, liquid, gas) and how temperature affects them. The students wrote experiments to prove that increasing temperature will cause matter to go from solid to liquid to gas and decreasing temperature will do the opposite. I pushed my students to think about something else we could experiment with, besides water, to test this. They decided on marshmallows. So we put some water in a pan with a couple of marshmallows and melted them. We were all fascinated. Gradually we watched all of the water boil off. The students were able to figure out that if there was something left in the pan when all the water was gone then we would know that marshmallows don't become gas. So, this is what was left in the pan. We did talk about the fact that we couldn't get it any hotter to see if a hot enough temperature would cause it to become gas. Then we got interested in several other questions about marshmallows and began doing some research on the computer and smartboard. We left the pan on just to see what would happen. All of the sudden students got really excited and pointed over at the pan. It was bubbling up in a gooey mess and there was a lot of smoke. A couple of students ran over to open the windows (it was below freezing outside) and another opened our classroom door. I stood there waving the pan around trying to figure out how I would explain this to my administrators if we set of the smoke alarm and the whole school had to evacuate. We left the pan sitting in the room for the rest of the day (not on any heat, of course) and students kept stopping by to feel it and observe. I'm not sure what all they learned, but I'm sure they were asking questions, making observations, and behaving like scientists. Probably more than any other time this year.
And, it wasn't as bad as the HazMat visit last year.