Friday, June 20, 2014

Fossils and Seashells

Like things that fly and all things medieval, fossils have the power to capture children's imaginations in an instant. The beauty of a long extinct life-form transformed into rock is a mystery that most children are eager to investigate. 

Combine the wonder of fossils with a walk through a real, naturally-made limestone cave and you have a recipe for inquiry that might last for weeks. Alas, we only have a week of school left, so we're delving into fossils without getting too deep (no pun intended!)

In preparation for our upcoming class trip to the amazing Bonnechere Caves, we've been learning about geology and fossils. The Caves are our local geological wonder. 500 million year-old fossils embedded in the mud and sand layers of an ancient sea have created a limestone bed on which much of our present-day farmland sits. 

About 10 000 year ago when the last of the Ice Age's glaciers were receding, the run-off eroded the cracks that naturally occurred in this ancient limestone. As limestone is a relatively soft rock, the crack widened over time, eventually forming a beautiful series of subterranean caverns.

Now a popular tourist destination, the Caves staff offer guided tours throughout the summer and fall.

I wanted to give my class some background in hopes that they would have lots of questions by the time we take our tour at the Caves next week. Having been a tour guide at the Caves in my late teens and early twenties, I gave them the short version using chart paper to draw ancient sea creatures! 

We watched this Bill Nye video about fossils, and in it we saw some children making fossils using shells, plasticine, and plaster of Paris. When the questions arose: could we do that?, all I could do was what I always try  to say: I said, YES!

I found a carton of plaster that I'd seen sitting in the supply cupboard for years. It didn't take much to organize small groups to knead their plasticine, squish a shell into it to create an imprint, then carefully pour or spoon some plaster of Paris into their mold. 

Within an hour they were ready to pop out, and now they're curing on the sunny windowsill till Monday. 

It was quick, it was messy, it was hands-on, and it was fun! The children were very excited to see their "fossils", and I know they'll have lots to think about as we embark on our subterranean adventure next week!

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