Friday, September 28, 2012

Volcano Unit Lesson Plan, Igneous Sugar, and Frosting Island Chain

I knew our study of volcanoes (or is it volcanos? "Volcanos" is listed as an alternate spelling in the dictionary, but neither way looks right to me!) would be fun, because the children have always loved volcanoes! Well . . . who doesn't? (The citizens of Pompeii, perhaps?) There were tons of good books at the library (even a non-ruined pop-up book!) and of course, there are millions of good volcano projects to do!

One of the first things we did, because this takes a few days to finish, was make "igneous sugar."  We found it on The Happy Scientist---it's a great experiment with crystal formation that helps show the difference between intrusive and extrusive igneous rocks---and, correspondingly, magma and lava. You have to let the sugar cool and crystallize for several days---although it doesn't have to be set all the way through; it just needs a "crust" that you can break off on top. The quick-cooling sugar is like lava (extrusive), and forms small crystals like this. It's analogous to basalt:
Here's a picture of both kinds together. Kind of hard to see. The top formation, like magma under earth's crust, cooled slowly and thus formed larger crystals.

Like granite! You can see it much better here.
This project took some patience but the children loved it---it was such a memorable way to remember the difference between the types of igneous rocks.
They also liked eating pieces of the sugar crystals!

Another thing we tried was making an island chain over a magma (frosting) "hot spot" in the earth's crust.  You just  poke holes in a foil-covered piece of cardboard, put frosting into a bag, and squeeze it out slowly as someone moves the cardboard over the tip of the bag. The idea is that the frosting extrudes up through the  holes and forms islands. It was a good idea, but didn't work too well (our plastic bag kept breaking---I needed an icing bag, I guess). Luckily I had the good sense to put newspaper on the floor first, but Daisy still ended up with frosting in her hair!

Oh yes---for this unit, if we hadn't made this stratovolcano model, we would definitely have made our favorites, these volcano cakes! We have discussed what to call them (most recipes say "Lava cakes") and we like volcano cakes best. "It wouldn't be lava cakes, anyway---it would be magma cakes," Sebby said. "Until you bit into them and it came out as lava!" Abey countered. The point was moot, as we didn't make them. But no doubt we will again soon!

1 comment:

  1. I'm stealing this idea next spring when we study rocks. You are awesome.


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