My 7 year old has been studying different types of rocks recently and this week we've been learning about metamorphic rock. Metamorphic rocks start out as igneous rock (volcanic rock) or sedimentary rock (made from sediment) but are changed by exposure to extreme heat and pressure within the Earth. This process is called metamorphism and can change both the physical appearance and the chemical make up of the rock. In this post I'll share a simple but fun way to demonstrate how metamorphic rock is formed.
For this demonstration you'll need a few colors of modeling clay, a sheet of waxed paper, and a few heavy books. Start by making small balls of clay in several colors. About 10-15 should be enough.
These are your "rocks". Arrange your clay rocks into a pile.
Next, cover your clay rock pile with the waxed paper, waxed side down. Then stack your heavy books on top. You can even apply extra pressure with your hand if necessary. This is to simulate high pressure caused by tectonic activity.
Remove the books and peel the waxed paper.
The pressure has caused your clay rocks to change, just like real tectonic activity can change igneous and sedimentary rocks into new rocks. They no longer look the same on the outside or the inside.
Use a butter knife to cut your new clay rock in half to see that it has also changed on the inside.
If you enjoyed this post check out my post about our geology hike and my post about how to make your own mineral identifying kit.
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