Most rocks are not made of paper towels. Metamorphic rocks, especially, are not made of paper towels, though they are perhaps the most interesting of all rock types in terms of how they’re formed deep in the bowels of the earth. This handy dandy Demo Science science demo will help demonstrate how these decidedly not-made-of-paper-towels rocks are formed, using—you guessed it—paper towels.
Winner of the 2015 Golden Globe for Outstanding Performance in A Soil Element Role
This experiment is so simple you’ve probably something very similar to it countless times without even realizing it was, in fact, science. You’re quite crafty, but not very observant, apparently. No worries.
All you’ll need is a roughly one-foot length of paper towel(s) and water in a spray bottle. Any sort of liquid will work, really, but I’d advise against hot sauce or wolf urine. Experience is a harsh teacher, but an effective one.
Explain to your students (or whomever you’re demonstrating for) that the paper towel represents a layer of metamorphic rock. Metamorphic rocks, of course, are famous for their many folded layers, which can vary greatly depending upon the deformative forces in play during their creation.
Push the paper towel together from opposite ends; this will cause a bulge. Release the pressure, and the paper towel will flatten out again, returning to more or less its original shape (minor fluffling* may occur). Manually flatten it out as needed.
Spray the paper towel with your liquid of choice, then push it together from the ends again. This time, instead of billowing upward harmlessly, the paper towel with smush together and wrinkle, producing “folds” as one might “see them” in “metamorphic rock.”
And the Award for Best Supporting Science Goes To…
The first time through, the billow of the paper towel is analogous to a geologic uplift event. Tectonic plates in the earth’s crust press together, and the rock in between bulges upward (or downward, or sideward). After weathering (or being sprayed with liquid) and additional pressure, the rock folds, marking a permanent change in the rock itself.
These effects are part of what geologists call the “rock cycle,” which sounds like a motorbike one of the bad guys from Teenage Mutant Ninja Turtles would ride.
* A real word I just made up.