‘Bread Rocks’ Make a Fun Metamorphic Science Experiment

Bread Metamorphic RocksBread Rock Experiment – Learning how Metamorphic Rocks from from sedimentary rocks.

As sediments build up in layers over time, they may become compressed and turn into a sedimentary rock. 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 will allow you to create your own sedimentary rock then with exposure to heat and pressure, change it into a metamorphic rock!

You will need:

  • Bread (at least three slices – try to use different colors like white, wheat, and/or rye)
  • Mini Marshmallows
  • Mini Chocolate chips
  • White Chocolate chips
  • Butterscotch chips
  • Wax paper
  • Foil

To Do the Experiment:

Bread Rocks Experiment Steps

Step 1: Layer the bread slices with mini marshmallows, chocolate chips, white chocolate chips and butterscotch chips. 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 stove top. If you have access to a microwave, you can also heat it for a few seconds on low power.

Observe:  Did the heat cause any changes in the bread rock? Did the marshmallows or chocolate chips begin to melt and change from their original state?

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. Usually, we equate one minute of standing for each one million years of pressure.

Observe:  Did the pressure cause any changes in the bread rock? Did the marshmallows or chocolate chips change shape or pattern? Are the rocks layers easy or difficult to separate after the metamorphism?

This experiment is great for kids of any age. Beware, many of the kids will want to eat their metamorphic rocks (eew, gross!) so make sure you wrap them well before the kids stand on them. This is one of the great experiments in our Rock Detectives Camp Guide. If you have any questions about this experiment or any others in our guide or on our site, contact us and we will be happy to help.

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