What are Sedimentary Rocks?
Sedimentary rocks are made up of tiny bits worn off of other rocks by wind, water and ice. Those tiny bits, like the sand and pebbles in this kit, are called sediment. Over time, they pile up and turn back into solid rock. This experiment can be found in the book Rocks & Minerals by Steve Tomecek, which is available to borrow at the library. This kit contains enough material to make 2 rocks so you can experiment with how thin or thick you make each layer, and compare your final results!
Supplies: Disposable cup, sand, pebbles and glue
Step 1: Cover the bottom of the cup with a layer of sand (just enough to cover it). Then pour a thin layer of white glue on top of the sand. Make sure all of the sand is covered.
Step 2: Add a single layer of pepples, then cover with another layer of glue. Be careful to use just enough glue to cover the pebbles.
Step 3: Add another layer of sand, then a final layer of glue. Your cup should be no more than half full, and it’s ok if it’s less. You can see the layers when you look at the side of the cup.
Step 4: Find a safe spot to set your cup. After 1 week, check if your rock feels solid. If it still feels squishy, leave it longer to dry. Once it feels hardened, cut the cup and peel it away from the rock. If the bottom is still a bit wet, set it that side up and allow it to dry completely.
Examine and compare your finished rocks. How do they appear similar or different? How did the amount of material you added in each layer affect each rock? Share pictures of your final results with us by emailing to firstname.lastname@example.org or tag us on Facebook and Instagram!