Activity 8

Metamorphism is the change that takes place within a body of rock as a result of it being subjected to conditions that are different from those in which it is formed. It is from the Greek word “meta” means change and “morphe” means form. 

        As sediments build up in layers over time, they may become compressed and turn into sedimentary rocks. A significant increase in pressure with low to moderate temperature increases may cause metamorphism to take place and turn the rock from sedimentary to metamorphic.

 This experiment lets kids create their own sedimentary rocks, expose them to high heat and pressure, and observe the changes. These fun “Bread Rock” are made of all edible materials from the grocery store so they are easy and fun to make.

To simulate the effects of pressure.

Bread (at least three slices – try to use different colors like white, or  wheat)- or any available bread

Mini Marshmallows

Mini Chocolate chips

White Chocolate chips

Butterscotch chips or any available chips

Wax paper or any available clean paper

Foil

Step 1: Layer three or more bread slices with mini marshmallows, chocolate chips, white chocolate chips, and butterscotch chips in between each layer. You can create the sediment layers in any manner you choose. If you choose to make patterns on one or more of the layers it will help you to see changes in your “rock.” Sketch your rock on a sheet of paper so you remember the pattern.

Step 2: Place the bread rock onto the waxed paper or foil and sit in a warm location such as outdoors on a hot day or on a stovetop. If you have access to a microwave, you can also heat it for a few seconds on low power.

Step 3: Place a piece of waxed paper or foil on top of the bread rock and stand on the rock for one to three minutes to represent millions of years of pressure on the rock. Stand on the bread rock for one minute for each one million years of pressure.

Step 4: Take pictures of every step in the experiment

1. Did the heat cause any changes in the bread rock? How?

2. Did the marshmallows or chocolate chips begin to melt and change from their original state? How?

3. How did the pressure cause any changes in the bread rock?

4.  Did the marshmallows or chocolate chips change shape or pattern? Why?

5. Are the rocks layers easy or difficult to separate after the metamorphism?