I don’t know a kid who does not have a rock collection, even if it’s just one favorite stashed on a shelf somewhere. I personally have piles of rocks all over my house. Rocks fascinate kids — it’s not hard to get them excited about a cool rock. They’re beautiful, they feel good in the hand, and because they come from the inside of the earth, they’re mysterious. Let’s find out some easy ways to have fun with kids and rocks.
The basics of rocks
In school, we learn that rocks come in three types. Igneous rocks come from cooled and hardened magma, which is what we call melted minerals below the earth’s surface. Igneous rocks can be formed above or below ground, and igneous rocks can have holes or pockets (like pumice), be smooth (like obsidian), or rough (like granite).
Sedimentary rock forms when sand, mud and other small rocks are laid down in layers, usually at the bottom of an ocean, river or lake. When more and more layers form, the layers on the bottom are squashed so much that they harden into rock. Some examples are sandstone, shale and coal.
Metamorphic rocks form when other rocks get squashed and heated enough that they change shape. They can be made from any other kind of rock. Some examples are marble, gneiss, and schist.
So why does geology matter to us? Well, rocks are literally the basis for everything we do. They make up the soil that allows us to grow food, like our fruit trees. The kinds and sizes of rock in the soil determines what kinds of food we can grow. Also, we have to know about the rocks under our feet before we build houses and roads, or they might collapse. Geology can even give us warnings when a volcano is about to erupt, and let us know where we can expect a landslide. This means geology not only rocks, but it’s important to human life too!
Exploring rocks with kids
Children don’t need a whole lot of encouragement to play with rocks, but here are a few activities if you need a bit of prompting.
With any topic, my first recommendation is to get out and experience it for yourself! Go for a rock hunt! Head out on our local trails and try to see as many different kinds of rocks as you can find. Be thoughtful when you want to collect rocks, knowing that the one rock you take might not be noticeable — but what if everyone took a rock? Instead, take photos. Compare and contrast. We are lucky to live in an area with all three kinds of rock — see if you can find all three kinds.
I like to explore the rock cycle using food. Here’s a recipe for rock cycle brownies:
Sixteen graham crackers and ½ cup butter are your igneous rock. Melt the butter in a bowl. Using a blender or a Ziploc and a rolling pin, become a force of erosion and mash the graham crackers into little tiny crumbs. Talk to your kids about how erosion happens because of wind and water breaking bigger rocks into little ones. Now, we’ll make sedimentary rock. Lay down your weathered graham cracker into a layer, and pour a layer of melted butter on top. Press down to form your first layer of sedimentary rock. Then, add one can of condensed milk (mud), and a layer of coconut flakes (1.5 cups – this is your shells, leaves, wood, etc.), and chocolate chip (1 cup — this represents pebbles, rocks and boulders). Now you have your sedimentary rock. Finally, to turn all this into metamorphic rock (and a delicious treat), press gently and heat in a 350-degree oven for 25-30 minutes.
Hillary Schwirtlich, membership and education coordinator for the Chelan-Douglas Land Trust, loves introducing people of all ages to the beauty and wonder of North Central Washington.