Metamorphic rocks can form from igneous, sedimentary or other metamorphic rocks. Metamorphism means changed form and involves the recrystallization of existing rock. The agents of change are heat and pressure. See how all of this works together when you make your own metamorphic "rock".
Recipe for Metamorphism
What you will need: One box of Kellogg's Rice Krispies cereal, with recipe for Rice Krispies Treats, marshmallows, margarine, 1 cup chocolate chips, saucepan or microwaveable bowl, rectangular baking pan, rangetop or microwave for cooking
The challenge: How does metamorphism work? How does it change the pre-existing "ingredients" for the new rock?
Try it this way: Measure the ingredients for the "metamorphic treats" and place the Rice Krispies, marshmallows and chocolate chips in three separate containers. These are the minerals in your rock. Note their shape and texture so that you can later describe the transformation. Crush the Krispies before you make the treats. Follow the recipe for making the treats, adding the cup of chocolate chips after the marshmallows are melted, and the pan has been removed from the heat. When the treats are completed and cooled, cute them into squares. Before you eat them, look carefully at their crystal structure.
What happens and
why: Describe the changes in the three minerals of your metamorphic
"rock." What caused the changes? How do these changes relate
to metamorphism in real rocks? You introduced a pressure change by crushing
the Krispies. How does this differ from the usual metamorphic process?
The Rock Cycle Web Site