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Geologic Recipes

Teach kids geology as they play with their food.



Potato, or meteorite?

Photo (c) Andrew Alden, licensed to About.com (fair use policy)

This is a contribution to Acretionary Wedge #30

All children play with their food, but what about kids who grow up to become Earth scientists? I know that long before I went to college, I was making my mashed potatoes into mountains. As they say, when I became a man I put away childish things. Mostly. I couldn't stop making lakes of butter or gravy atop my potato mountains, then sending the liquid down their flanks in molten eruptions.

One day I saw the great tectonicist J. Tuzo Wilson speak to a college audience. Here was the man who first grasped how the Earth's crustal plates fit together, one of the most eminent scientists in his field. And he said again and again that the crust behaves like large slabs of toffee—brittle where it's cool, near the surface, but plastic and yielding under deep heat and stress.

If J. Tuzo Wilson could look at geology that way, then we certainly can too. So let's reassess our children's table manners and turn their hijinks into some recipes for your budding geologists!

Potatoes are good for lots of things. A plain baked potato could be a boulder, or maybe a meteorite. Stuff it with something and call it a geode, or a thunder egg. But how about potato volcanoes? They're a regular on my table during the cold months. Just make your favorite mashed potatoes, then put a big crater in the middle of each serving. Fill this with any number of savory things—cheese, chili, mixed vegetables with good olive oil, spicy dal, soft lima beans with butter and pepper.

Rock candy is always there to introduce your child—or remind yourself—of the beauty of crystals. And loose sugar is a good sand substitute. But did you know that experimentalists use heavy syrups to model the behavior of various underground bodies, like salt domes or magma chambers?

Geology teachers often compare sedimentary rock explosures to layer cakes. But we can go further into desserts and consider rocky-road candy as an example of various "mixed stones" like breccia, or even chondritic meteorites. And raisin cookies illustrate phenocrysts in a magma quite nicely.

Then there's metamorphism, where deeply buried rocks and sediments become altered under the heat and fluids down there. Some minerals break down and liberate water, and other minerals incorporate it. Salts and acids become active, and the result is a sediment transformed into something new. The process is a great deal like baking a set of distinct ingredients into a savory lasagna.

All right, maybe some of that is far fetched. But remember the next time you bake cookies and they come out a little dark or rough—just call them "rocks" instead. Maybe your kids have done the cookie mining exercise at school and they'll eat your mistakes enthusiastically. That and many other activities are listed at the Kentucky Geological Survey's first-rate educational site, on the Geologic and Paleontologic Cook Book page.

PS: I've written another article about recipes for volcanoes that touches on this subject too. The soufflé, for example, demonstrates some important behaviors of violent eruptions.

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