Yesterday, my students created a sinkhole. OK, they had a little help from Science World magazine, but still...they made a sinkhole.
If you do not live in a Karst region, you will not understand the significance of a sinkhole. Missouri is like the Sinkhole King. Take that, Mississippi! I, personally, am the proud owner of four sinkholes. That I am aware of. Three are right out the front door. Farmer H thinks a sinkhole is nature's wastebasket. He has been know to toss things in there without telling me. Such as a set of old kitchen cabinets that we tore out of our rental house. And a dead possum. But I put a stop to that. Because I do not want to drink dead possum water from our well.
Anyhoo, getting back to my students and their sinkholes...the materials used were sugar cubes and crackers. The sugar cubes represented limestone or dolomite, rocks that react with carbonic acid as water seeps down through the soil. They dissolve, and voila! Sinkholes and caves appear. The crackers were layers of rock that do not dissolve. The models worked quite well.
Of course, the kids were more interested in the crackers and sugar cubes.
Hey! Can I eat a cracker?
I want one of those sugar cubes.
I loooove crackers!
C'mon. There's enough.
I had to remind them of our safety rules, specifically about not eating the lab materials. The worst part was, one of the kids wanted to eat the stuff after it had been soaked with water. Water from a beaker that had brown residue around the top, where somebody had not cleaned it thoroughly. Soggy, soaky, pasty crackers. With mystery residue. And it was the class right after lunch.
You know that if the cafeteria had served crackers and sugar cubes, there would have been quite an outcry. "What do you mean we have to eat crackers and sugar cubes! That's downright nasty. I can't believe you expect us to eat that crap. Seriously. It's like torture."
Which just goes to show you that we, as educators, have to protect the students from themselves.